Patent application number | Description | Published |
20080219235 | System and Method for Frequency Division Multiple Access Communications - A method and system for wireless frequency division multiple access communications in the uplink and/or downlink directions, having an improved pilot insertion scheme for single carrier based communications is provided. A first time duration for transmission of a data payload block ( | 09-11-2008 |
20080232504 | Methods and Systems For Ofdm Multiple Zone Partitioning - Aspects of the invention include methods and devices for inserting data and pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) frames having a time domain and a frequency domain. A method involves inserting in at least one zone of a first type a two dimensional array of data and pilot symbols in time and frequency and inserting in at least one zone of a second type a two dimensional array of data and pilot symbols in time and frequency. In some implementations the zone of the first type comprises common pilot symbols that can be detected by all receivers receiving the OFDM frame. In some implementations the zone of the second type comprises dedicated pilot symbols that are only detectable by a receiver that is aware of pre-processing used to encode the dedicated pilot symbols. According to various embodiments of the invention, the zones of the first and second types can be partitioned in the OFDM frame based on time division multiplexing (TDM), frequency division multiplexing (FDM) or combined TDM/FDM. Examples of types of transmissions that could be transmitted in different zones of a single OFDM frame are OFDM multiple input multiple output (MIMO) transmissions and OFDM beam forming transmissions. | 09-25-2008 |
20080247479 | Pilot Scheme For A Mimo Communication System - The present invention employs a pilot scheme for frequency division multiple access (FDM) communication systems, such as single carrier FDM communication systems. A given transmit time interval will include numerous traffic symbols and two or more short pilot symbols, which are spaced apart from one another by at least one traffic symbol and will have a Fourier transform length that is less than the Fourier transform length of any given traffic symbol. Multiple transmitters will generate pilot information and modulate the pilot information onto sub-carriers of the short pilot symbols in an orthogonal manner. Each transmitter may use different sub-carriers within the time and frequency domain, which is encompassed by the short pilot symbols within the transmit time interval. Alternatively, each transmitter may uniquely encode the pilot information using a unique code division multiplexed code and modulate the encoded pilot information onto common sub-carriers of the short pilot symbols. | 10-09-2008 |
20080253279 | Pilot Design for Ofdm Systems with Four Transmit Antennas - Pilot, preamble and midamble patterns are provided that are particularly suited for four transmit antenna OFDM systems. Pilots are inserted in a scattered manner for each of the four antennas, either uncoded, space-time coded in pairs, space-time frequency coded in pairs, or space-time-frequency coded. | 10-16-2008 |
20080253469 | Methods and Systems for Ofdm Using Code Division Multiplexing - In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions. | 10-16-2008 |
20080268844 | Handoffs and Handoff Selection in a Wireless Access Network - The present invention facilitates handoffs for a mobile terminal in a wireless access network that is capable of supporting different types of handoffs. The different handoff types may include soft handoffs and fast base station switching (FBSS). In operation, context information associated with supporting wireless communications between the wireless access network and the mobile terminal are determined. Based on whether the context information is shared between base stations involved in the handoff or transferred from one base station to another of the base station involved in the handoff, a particular handoff type is selected from the different handoff types that are available. Selecting the specific type of handoff to use may also be based on the level of context information that is available, the actual content of the context information, application preferences, channel conditions, base station or mobile terminal capabilities, or any combination thereof. | 10-30-2008 |
20080285499 | System and Method for Unbalanced Relay-Based Wireless Communications - A method and system for wireless communication with a mobile device in which wireless communication is established with the mobile device. A base station is used to transmit directly to the mobile device in a downlink direction. A relay node is used to transmit to the base station communications received in an uplink direction from the mobile station. The relay node relays at least a portion of the uplink traffic received from the mobile station to the base station. | 11-20-2008 |
20080285500 | Wireless Relay Network Media Access Control Layer Control Plane System and Method - A method and system for using a communication network having a relay node to provide wireless communication with a mobile station. A ranging region is established with the mobile station in which the establishment of the ranging region includes the transmission of control information corresponding to the relay node. The mobile station is allowed to enter the communication network. The relay node is used to wirelessly communicate with the mobile station in at least one of the uplink and downlink directions. | 11-20-2008 |
20080285501 | Media Access Control Data Plane System and Method for Wireless Communication Networks - A method and system for using a communication network having a relay node to provide wireless communication with a mobile station. A protocol stack is implemented in the relay node in which the protocol stack includes a media access control layer defining a media access control protocol. The media access control protocol defines a set of headers providing media access control layer data plane functions in the relay node. | 11-20-2008 |
20090003466 | System and Method for Mapping Symbols for Mimo Transmission - Methods and devices are provided for MIMO OFDM transmitter and receivers having odd and/even numbers of transmit antennas. Various methods for pre-coding information bits before space time coding (STC) are described for enabling transmission of information bits over all antennas. Methods of decoding received signals that have been pre-coded and STC coded are also provided by embodiments of the invention. Pilot patterns for downlink and uplink transmission between a base station and one or more wireless terminals for three transmit antenna transmitters are also provided. Variable rate codes are provided that combine various fixed rate codes in a manner that results in codes whose rates are dependent on all the various fixed rate codes that are combined. | 01-01-2009 |
20090022098 | MULTIPLEXING SCHEMES FOR OFDMA - Methods and systems are provided for allocating resources including VoIP (voice over Internet Protocol) and Non-VoIP resources. In some embodiments, multiplexing schemes are provided for use with OFDMA (orthogonal frequency division multiplexing access) systems, for example for use in transmitting VoIP traffic, in some embodiments, various HARQ (Hybrid Automatic request) techniques are provided for use with OFDMA systems. In various embodiments, there are provided methods and systems for dealing with issuea such as Handling non-full rate vocoder frames, VoIP packet jitter handling, VoIP capacity increasing schemes, persistent and non-persistent assignment of resources in OFDMA systems. | 01-22-2009 |
20090028258 | Methods and systems for transmission of orthogonal frequency division multiplexed symbols - In some embodiments of the present invention there is provided a frame structure for transmitting an integer number of OFDM symbols in which some of the OFDM symbols are to be transmitted in a unicast format and some of the OFDM symbols are to be transmitted in a broadcast format. The frame structure includes partitioning of a frame into at least two portions to accommodate both unicast and broadcast modes in the frame. The frame structure is used for transmitting multiple frames in a serial manner from at least one transmitter. The unicast mode supports transmission of OFDM symbols from a single transmitter to a single receiver. The broadcast mode supports transmission of OFDM symbols from multiple transmitters to all receivers within range of the multiple transmitters. The multicast mode supports transmission of OFDM symbols from multiple transmitters to multiple receivers within range of the multiple transmitters. | 01-29-2009 |
20090046797 | Method and System for Retransmitting Data Packets - A method and system are provided for minimizing errors by retransmitting packets in a multiple-input-multiple-output (MIMO) space-time coded packet radio. A packet is transmitted using a first STC code mapping, the mapping including well-known symbol operations, and optional signal weighting. When transmission errors are detected the packet is re-transmitted using STC code mappings selected in turn from a deterministic sequence of STC code mappings. The STC code mappings are chosen in accordance with one or more principles. | 02-19-2009 |
20090060076 | SYSTEM ACCESS AND SYNCHRONIZATION METHODS FOR MIMO OFDM COMMUNICATIONS SYSTEMS AND PHYSICAL LAYER PACKET AND PREAMBLE - A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame. | 03-05-2009 |
20090060081 | Systems and methods for ofdm channelization - Systems and methods for OFDM channelization are provided that allow for the co-existence of sub-band channels and diversity channels. Methods of defining diversity sub-channels and sub-band sub-channels are provided, and systematic channel definition and labeling schemes are provided. | 03-05-2009 |
20090060088 | Detecting the number of transmit antennas in a base station - Data is scrambled at a transmitter according to one of a number of predetermined scrambling sequences which are associated with a particular one of a number of predetermined transmit antenna diversity schemes (i.e., a specific number of transmit antenna ports). Received data is decoded using one or more of the known transmit antenna diversity schemes and the scrambled data is descrambled according to a corresponding descrambling sequence (related to the scrambling sequence). Based on the descrambled data, the receiver determines which transmit antenna, diversity scheme (i.e., the number of antenna ports) is used by the transmitter. In one specific embodiment, CRC parity data is scrambled in the transmitter and the receiver descrambles the recovered CRC parity data according to a descrambling sequence, computes CRC parity data from the received data, and compares the descrambled CRC parity data to the newly computed CRC parity data. | 03-05-2009 |
20090073916 | RANGING REGIONS FOR WIRELESS COMMUNICATION RELAY STATIONS - One embodiment of the present invention provides a unique ranging technique in wireless communication environments that employ relay stations associated with a base station. Each relay station, and optionally the base station itself, can be allocated a unique ranging region having unique ranging resources that may be used by a mobile station to initiate a ranging function with the corresponding relay station or base station. | 03-19-2009 |
20090083604 | Ldpc encoders, decoders, systems and methods - An LDPC encoder with a complexity that increases linearly as a function of block size is provided. They arc implementable with simple logic consisting of a repeater with an irregular repeat pattern, an interleaver, and an accumulator that performs irregular accumulations. | 03-26-2009 |
20090086648 | Rank Adaptation for an Open Loop Multi-Antenna Mode of Wireless Communication - To perform rank adaptation for a mobile station in a wireless network, it is determined whether the mobile station is fast moving. In response to determining that the mobile station is fast moving, an open loop multi-antenna mode is selected to perform wireless communication between the mobile station and a base station. Also, selection is made from among plural ranks for the wireless communication according to the open loop multi-antenna mode between the mobile station and the base station. | 04-02-2009 |
20090103494 | SOFT HANDOFF FOR OFDM - The present invention relates to soft handoffs in an OFDM system. Each mobile terminal measures pilot signal strengths of transmissions from adjacent base stations. If the pilot signal strength for a base station exceeds the defined threshold, that base station is added to an active set list. Each mobile terminal notifies the base stations of their active set lists. By providing the set list to the base station controller and the servicing base station, the mobile terminal identifies the sole servicing base station or triggers a soft handoff mode when multiple base stations appear on the active set list. The soft handoff mode uses a combination of scheduling and space-time coding to affect efficient and reliable handoffs. | 04-23-2009 |
20090129334 | Soft handoff in Ofdma system - The soft handoff in an OFDMA system. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone have subcarriers with a subchannel definition, for example, an identical permutation. | 05-21-2009 |
20090175230 | MAPPING OF DISTRIBUTED RESOURCE BLOCK INDICES TO PHYSICAL RESOURCE BLOCKS - An apparatus for communication using a wireless communication network includes an interleaver and a transceiver. The interleaver co-exists with a localized transmission arrangement if the localized transmission arrangement is present and interleaves data packets for a distributed transmission arrangement by mapping a set of logical indices to a set of physical resource blocks. The set of logical indices include sequential logical indices that are separated by a maximum spacing within the set. The transceiver is in electrical communication with the interleaver. The transceiver is operable to transmit and receive data packets through the wireless communication network. | 07-09-2009 |
20090213948 | ADAPTIVE TWO-DIMENSIONAL CHANNEL INTERPOLATION - A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency). | 08-27-2009 |
20090219838 | CLOSED-LOOP MIMO SYSTEMS AND METHODS - Methods, devices and systems are provided for transmitting and receiving MIMO signals. Transmitting of the MIMO signals involves pre-coding each of at least two data symbols using a respective pre-coding codeword to preclude a corresponding plurality of pre-coded data symbols. A respective signal is transmitted from each of a plurality of antennas, the respective signal including one of the pre-coded signals and at least one pilot for use in channel estimation. The signals collectively further include at least one beacon pilot vector consisting of a respective beacon pilot per antenna, the beacon pilot vector containing contents known to a receiver for use by the receiver in determining the codeword used to pre-code the at least one data signal. Receiving of the MIMO signals involves receiving a MIMO signal containing data symbols pre-coded with a codeword. The MIMO signal includes pilots, and including at least one beacon pilot vector containing contents known to a receiver/each beacon pilot vector containing one symbol from each transmit antenna. Processing is performed on the at least one beacon pilot vector to determine which codeword was used to pre-code the data symbols. | 09-03-2009 |
20090245197 | Methods and systems to mitigate inter-cell interference - The present invention provides methods and devices for mitigating inter-cell interference in communication environments having a plurality of cells. In some embodiments, a time-frequency transmission resource that includes multiple sub-carriers over multiple OFDM symbol intervals is partitioned into a first zone and a second zone. In the first zone, transmissions are transmitted on at least one frequency sub-band which is common to all of the plurality of cells. In the second zone, transmissions are transmitted on at least one frequency sub-band which is used by less than all of the plurality of cells, so as to mitigate inter-cell interference. In some embodiments, in the first zone transmissions are transmitted using a transmission power which is common to all of the plurality of cells and in the second zone transmissions are transmitted using a transmission power which is used by less than all of the plurality of cells so as to mitigate inter-cell interference. | 10-01-2009 |
20090252079 | METHODS AND SYSTEMS FOR WIRELESS NETWORKS WITH RELAYS - Methods and systems are provided for use with wireless networks having one or more cell in which each cell includes a base station (BS), at least one relay station (RS) and at least one mobile station (MS). The at least one relay station can be used as an intermediate station for providing communication between the BS and MS. Methods are provided for allocating OFDM resources for communicating between the BS, RS and/or MS for example dividing transmission resources into uplink and downlink transmissions and methods of inserting pilot symbols into transmission resources used by the RS. In some embodiments on the invention, the methods are consistent and/or can be used in conjunction with existing standards such as 802.16e. | 10-08-2009 |
20090274112 | Initial Access Channel for Scalable Wireless Mobile Communication Networks - Physical layer structures and access schemes for use in such networks are described and in particular initial access channel (IACH) structures are proposed. A spectrum efficient downlink (DL) IACH design supports different types of User Equipment (UE) capabilities and different system bandwidths. An IACH includes the synchronization channel (SCH) and broadcast-control channel (BCH). A non-uniform SCH for all system bandwidths is provided, as well as scalable bandwidth BCH depending on system bandwidth. An initial access procedure is provided, as well as an access procedure. | 11-05-2009 |
20090291700 | GRADUATED SINGLE FREQUENCY NETWORK - The signals from adjacent transmitters reinforce one another. As a result of this over-the-air combining, signal quality is improved in the network and especially at or near cell boundaries. The present invention provides a graduated single frequency network (GSFN) wherein transmitters in cells throughout a geographic area cooperate to broadcast data to user terminals throughout the geographic area, and adjacent transmitters transmit signals that substantially reinforce one another. When transmitting the data, transmitters in certain adjacent cells throughout the geographic area may employ slightly different transmit parameters to provide slightly different transmission signals. The transmission signals used to transmit the data may be varied in a graduated fashion throughout the geographic area, wherein even when there is a difference in the transmission signals of transmitters in adjacent cells, the transmission signals reinforce one another despite being different. | 11-26-2009 |
20090303918 | ZONES FOR WIRELESS NETWORKS WITH RELAYS - Methods and systems are provided for use with wireless networks having once or more cell in which each cell includes a base station (BS), at least one relay station (RS) and at least one mobile station (MS). The at least one relay station can be used as an intermediate station for providing communication between the BS and MS. Methods are provided for an RS to initially access the network, access of the RS by MSs initially accessing the network, methods of allocating OFDM resources for communicating between the BS, RS and/or MS for example dividing transmission resources into uplink and downlink transmissions, and methods of inserting pilot symbols into transmission resources used by the RS. In some embodiments on the invention, the methods are consistent and/or can be used in conjunction with existing standards such as 802.16e. | 12-10-2009 |
20100002801 | PRECODING IN HIGH-ORDER MIMO - A high-order Multiple-Input-Multiple-Output (MIMO) transmitter implementing a covariance-based precoding scheme that exploits transmit channel correlation and a method of operation thereof are provided. In one embodiment, covariance-based precoding is performed at the high-order MIMO transmitter based on feedback from a remote high-order MIMO receiver regarding a covariance-based precoding matrix. The covariance-based precoding matrix is, or is derived from, a transmit channel correlation matrix determined by the high-order MIMO receiver for the high-order MIMO transmitter. The covariance-based precoding provides a beam-forming effect when there is a relatively high degree of transmit channel correlation, thereby improving performance of the high-order MIMO transmitter. Further, because changes in the transmit channel correlation occur relatively slowly over time, feedback overhead requirements are substantially reduced as compared to that required for traditional MIMO precoding schemes. | 01-07-2010 |
20100226334 | PHYSICAL LAYER STRUCTURES AND INITIAL ACCESS SCHEMES IN AN UNSYNCHRONIZED COMMUNICATION NETWORK - Physical layer structures and related access schemes for unsynchronized communication networks are provided. Access channel information, preferably including a common synchronization code associated with all transceiver stations in a communication network and a cell-specific synchronization code uniquely associated with one of the transceiver stations, is modulated onto at least one set of time-continuous signal components of a communication signal. In order to access the communication network, communication terminals search for the access channel information in one or more sets of time-continuous signal components and synchronization parameters are then determined based on a location of the access channel information in the sets of time-continuous signal components. Some embodiments of the invention provide for joint frame synchronization and coarse timing synchronization. In further embodiments, the communication signal also includes a scattered pilot channel onto which a portion of the access channel information, preferably the cell-specific synchronization code, is modulated. The pilot channels may then be re-used for initial access operations in addition to its conventional uses for such operations as channel estimation. | 09-09-2010 |
20100271930 | SCATTERED PILOT PATTERN AND CHANNEL ESTIMATION METHOD FOR MIMO-OFDM SYSTEMS - Methods and apparatus are provided for inserting data symbols and pilot symbols in an OFDM (orthogonal frequency division multiplexing) transmission resource utilizing frequency hopping patterns for the data symbols and/or the pilot symbols. Data symbols and pilot symbols are allocated for down link (base station to mobile station) and up link (mobile station to bases station) transmission resources in a two-dimensional time-frequency pattern. For each antenna of a MIMO-OFDM (multiple input multiple output OFDM) communication system, pilot symbols are inserted in a scattered pattern in time-frequency and data symbols are inserted in an identical frequency-hopping pattern in time-frequency as that of other antennas. | 10-28-2010 |
20100284480 | METHOD AND APPARATUS FOR CHANNEL QUALITY MEASUREMENTS - A method and apparatus are provided for measuring channel quality over which has been transmitted a sequence of symbols produced by encoding and constellation mapping a source data element sequence. The method includes receiving a sequence of received symbols over the channel whose quality is to be measured. The sequence of received symbols is de-mapped based on a first channel quality indicator previously transmitted to a transmitter of the sequence of symbols. The method also includes decoding the de-mapped symbols to produce a decoded output sequence. In some embodiments, the decoding may be based on the first channel quality indicator. The method also includes re-encoding the decoded output sequence to produce a re-encoded output sequence. The method also includes correlating the de-mapped symbols with the re-encoded output sequence to produce a second channel quality indicator. The second channel quality indicator is transmitted to the transmitter to adaptively select a type of mapping based on the second channel quality indicator. In some embodiments, the transmitter may adaptively select a type of encoding based on the second channel quality indicator. | 11-11-2010 |
20110019605 | MULTIMEDIA BROADCAST MULTICAST SERVICE (MBMS) UTILIZING SPATIAL MULTIPLEXING - Systems and methods are disclosed herein for an enhanced Multimedia Broadcast Multicast Service (MBMS) in a wireless communications network. In one embodiment, a number of base stations in a MBMS zone, or broadcast region, accommodate both Spatial Multiplexing (SM) enabled user elements and non-SM enabled user elements. In another embodiment, a number of base stations form a MBMS zone, or broadcast region, where the MBMS zone is sub-divided into an SM zone and a non-SM zone. In another embodiment, the wireless communications network includes multiple MBMS zones. For each MBMS zone, base stations serving the MBMS zone transmit an MBMS zone identifier (ID) for the MBMS zone. The MBMS zone ID may be used by a user element for decoding and/or to determine when to perform a handoff from one MBMS zone to another. | 01-27-2011 |
20110075651 | SYSTEMS AND METHODS FOR SC-FDMA TRANSMISSION DIVERSITY - The present application provides methods, devices and transmitters that mitigate increases in peak to average power ratio (PAPR) from transmission diversity in a single carrier frequency division multiple access (SC-FDMA) modulated uplink A PAPR preserving precode matrix hopping method that utilizes cyclic shift delays is provided, as well as a sub-band based transmit diversity scheme. The present application also provides methods, devices and transmitters that relax the scheduling restrictions associated with uplink scheduling in the LTE standard. | 03-31-2011 |
20110081943 | System and Method for Supporting Multi-User Antenna Beamforming in a Cellular Network - The present invention is a method and system for supporting a beamforming antenna system in a multiple user mobile broadband communication network including a process for setting and adjusting the magnitude and phase of the signal to user equipment from each antenna. Namely, the present invention supports the communication of power signal values or levels to user equipment in a manner that keeps pace with the rapid variations of the power levels that occur in the dynamic scheduling of transmissions on the cell site. The present invention satisfies this need for an improved signal strength signaling to user equipment for the situation where multiple users are located on the cell site. | 04-07-2011 |
20110096751 | SOFT HANDOFF FOR OFDM - The present invention relates to soft handoffs in an OFDM system. Each mobile terminal measures pilot signal strengths of transmissions from adjacent base stations. If the pilot signal strength for a base station exceeds the defined threshold, that base station is added to an active set list. Each mobile terminal notifies the base stations of their active set lists. By providing the set list to the base station controller and the servicing base station, the mobile terminal identifies the sole servicing base station or triggers a soft handoff mode when multiple base stations appear on the active set list. The soft handoff mode uses a combination of scheduling and space-time coding to affect efficient and reliable handoffs. | 04-28-2011 |
20110134772 | Methods of radio communication involving multiple radio channels, and radio signal repeater and mobile station apparatuses implementing same - A method of facilitating radio communications involves receiving a first message from a first remote radio station on a first radio channel, transmitting the first message to a second remote radio station on a second radio channel, receiving a second message from the second remote radio station on a third radio channel, and transmitting the second message to the first remote radio station on a fourth radio channel. A method of radio communication involves receiving a first radio signal from a first remote radio station on a first radio channel, transmitting a second radio signal to the first remote radio station on a second radio channel, receiving a third radio signal from a second remote radio station on a third radio channel, and transmitting a fourth radio signal to the second remote radio station on a fourth radio channel. Radio signal repeater and mobile station apparatuses are also disclosed. | 06-09-2011 |
20110149824 | SYSTEM AND METHOD FOR SPATIAL MULTIPLEXING-BASED OFDM BROADCAST/MULTICAST TRANSMISSION - A method of OFDM transmission/reception comprising: transmitting broadcast/multicast signals on a first antenna and unicast signals on a second antenna; segregating broadcast/multicast sub-channelization from unicast channels sub-channelization based on FDM (frequency division multiplexing)/TDM (time division multiplexing) sub-channelization. | 06-23-2011 |
20110158156 | METHOD AND SYSTEM USING RELAYS WITH AGGREGATED SPECTRUM - International Mobile Telecommunications (IMT) Advanced technology, also known as 4th Generation (4G) targets to support up to 100 MHz BW. LTE currently supports single carrier bandwidths of up to 20 MHz. The present application describes a multi-carrier approach in which some embodiments of the invention provide a simple solution of aggregating multiple single carrier bandwidths to obtain a wider bandwidth (>20 MHz). Such an approach may extend Long Term Evolution (LTE) bandwidth to greater than that provided by a single carrier, yet maintain full backward compatibility with technologies that predate 4G technology and utilize smaller, single carrier bandwidths. More generally, embodiments of the invention can apply to other communication standards than only LTE. | 06-30-2011 |
20110159811 | White Wireless Network - Aspects of the present invention provide a multi-band hybrid Gigabit wireless communication system which is enabled by a number of different complementary access technologies to realize ubiquitous hyper-connectivity, true broadband, seamless operation and low power consumption. The system is capable of serving fixed, nomadic and mobile scenarios. The multi-band wireless system is a low power wireless system which operates in different frequency bands covering the spectrum from radio wave to optical wave by making use of both regulated bandwidths and unregulated bandwidths. Using low power distributed antenna and low power indoor and outdoor antennas enables the use of unregulated bandwidths as well as regulated bandwidths as the low power nature of the signals reduces the possibility of interference with the regulated use of the signals. | 06-30-2011 |
20110164491 | METHOD AND SYSTEM FOR COMBINING OFDM AND TRANSFORMED OFDM - Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM. | 07-07-2011 |
20110164492 | METHOD AND SYSTEM FOR COMBINING OFDM AND TRANSFORMED OFDM - Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM. | 07-07-2011 |
20110164878 | METHOD AND SYSTEM FOR IMPLEMENTING A WIRELESS NETWORK - Aspects of the present invention provide a multi-band hybrid Gigabit wireless communication system which is enabled by a number of different complementary access technologies to realize ubiquitous hyper-connectivity, true broadband, seamless operation and low power consumption. The system is capable of serving fixed, nomadic and mobile scenarios. The multi-band wireless system is a low power wireless system which operates in different frequency bands covering the spectrum from radio wave to optical wave by making use of both regulated bandwidths and unregulated bandwidths. Using low power distributed antenna and low power indoor and outdoor antennas enables the use of unregulated bandwidths as well as regulated bandwidths as the low power nature of the signals reduces the possibility of interference with the regulated use of the signals. | 07-07-2011 |
20110199996 | METHOD AND SYSTEM FOR ALLOCATING MEDIA ACCESS CONTROL LAYER RESOURCES IN A WIRELESS COMMUNICATION ENVIRONMENT - A method and system for allocating shareable wireless transmission resources. A resource pool is established. The resource pool is divided into a plurality of physical layer allocation units usable for wirelessly transmitting control information and traffic data. The allocation units are assigned at the media access control layer for the wireless transmission of the control information and traffic data. The system and method of the present invention also allows mobile stations to be dynamically grouped into multicast groupings to reduce system overhead resource requirements. | 08-18-2011 |
20110200029 | WIRELESS COMMUNICATION CLUSTERING METHOD AND SYSTEM FOR COORDINATED MULTI-POINT TRANSMISSION AND RECEPTION - A method and system for identifying cell clusters within a coordinated multiple point wireless transmission network in order to reduce scheduling complexity while optimizing throughout and performance. The network includes a total number of cells served by corresponding base stations. The BSC divides the entire network of cells into clusters of cells and forwards this clustering information to all mobile devices. A cluster of cell candidates is a subset of the total number of cells within the network. The mobile device then provides to a base station controller the identity of a cluster of preferred cells selected from the cluster of cell candidates. The base station controller selects at least one base station located within the cluster of preferred cells to establish communication with the mobile device. A wireless connection is then established between the selected at least one base station and the mobile device. | 08-18-2011 |
20110216808 | SCATTERED PILOT PATTERN AND CHANNEL ESTIMATION METHOD FOR MIMO-OFDM SYSTEMS - Methods and apparatus are provided for inserting data symbols and pilot symbols in an OFDM (orthogonal frequency division multiplexing) transmission resource utilizing frequency hopping patterns for the data symbols and/or the pilot symbols. Data symbols and pilot symbols are allocated for down link (base station to mobile station) and up link (mobile station to bases station) transmission resources in a two-dimensional time-frequency pattern. For each antenna of a MIMO-OFDM (multiple input multiple output OFDM) communication system, pilot symbols are inserted in a scattered pattern in time-frequency and data symbols are inserted in an identical frequency-hopping pattern in time-frequency as that of other antennas. | 09-08-2011 |
20110222504 | PREAMBLES IN OFDMA SYSTEM - The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-I and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems. | 09-15-2011 |
20110228728 | METHOD AND SYSTEM FOR SPACE CODE TRANSMIT DIVERSITY OF PUCCH - Aspects of the invention are directed to a transmit diversity method for use in a wireless terminal having a plurality of antennas and a wireless terminal configured to implement the method. The transmit diversity method includes using a different orthogonal sequence for each antenna, or group of antennas, for transmitting an uplink control channel from a wireless terminal to a base station. A first step of the method involves assigning at least one orthogonal sequence to one or more of the plurality of antennas, each of the plurality of antennas being assigned at least one orthogonal sequence. Once the orthogonal sequence is assigned, a further step involves scrambling a signal to be transmitted on the physical uplink control channel (PUCCH) using the at least one orthogonal sequence for each antenna thereby producing a scrambled PUCCH for transmission by each antenna. The scrambled PUCCH can then be transmitted on the plurality of antennas. | 09-22-2011 |
20110235562 | SYSTEM AND METHOD FOR SPATIAL MULTIPLEXING-BASED MULTIPLE ANTENNA BROADCAST/MULTICAST TRANSMISSION - Methods and devices are provided for implementing two types of sub-channel arrangements. A first type of sub-channel arrangement involves defining a first traffic portion and a second traffic portion of a transmission resource, transmitting broadcast traffic on at least one first antenna of a plurality of antennas in the first traffic portion using a first sub-channelization, transmitting multicast traffic on at least one second antenna of the plurality of antennas, the at least one second antenna being distinct from the at least one first antenna, in the first traffic portion using a second sub-channelization, and transmitting unicast traffic on at least one antenna of the plurality of antennas in the second traffic portion using a third sub-channelization. A second type of sub-channel arrangement involves defining a first traffic portion and a second traffic portion, wherein for a portion of the transmission resource, a portion of the first traffic portion overlaps with a portion of the second traffic portion. In the portion of the transmission resource in which a portion of the first traffic portion overlaps with a portion of the second traffic portion, the channel arrangement involves transmitting broadcast/multicast traffic on at least one first antenna of a plurality of antennas using a first sub-channelization and b) transmitting unicast traffic on at least one second antenna of the plurality of antennas, the at least one second antenna being distinct from the at least one first antenna, using a second sub-channelization. The first, second and third sub-channelizations may be based on either one of or a combination of FDM sub-channelization and TDM sub-channelization. | 09-29-2011 |
20110261781 | METHOD AND SYSTEM FOR PROVIDING AN UPLINK STRUCTURE AND MINIMIZING PILOT SIGNAL OVERHEAD IN A WIRELESS COMMUNICATION NETWORK - A method and system are provided having an uplink control structure and a pilot signal having minimal signal overhead for providing channel estimation and data demodulation in a wireless communication network. The uplink control structures enable mobile terminals to communicate with corresponding base stations to perform various functions including obtaining initial system access, submitting a bandwidth request, triggering a continuation of negotiated service, or providing a proposed allocation re-configuration header. A dedicated random access channel is provided to communicatively couple the base station and the mobile terminal so that the mobile terminal can select a random access signaling identification. A resource request is received at the base station to uplink resource information from the mobile terminal and an initial access information request is received from the mobile terminal to configure the base station connection. Pilot signals with varying density configurations are provided to include low density symbol patterns for multiple contiguous resource blocks and high density symbol patterns for single resource blocks. | 10-27-2011 |
20110286349 | Method and System for User Equipment Location Determination on a Wireless Transmission System - Neighbor cell hearability can be improved by including an additional reference signal that can be detected at a low sensitivity and a low signal-to-noise ratio, by introducing non-unity frequency reuse for the signals used for a time difference of arrival (TDOA) measurement, e.g., orthogonality of signals transmitted from the serving cell sites and the various neighbor cell sites. The new reference signal, called the TDOA-RS, is proposed to improve the hearability of neighbor cells in a cellular network that deploys 3GPP EU-TRAN (LTE) system, and the TDOA-RS can be transmitted in any resource blocks (RB) for POSCH and/or MBSFN subframe, regardless of whether the latter is on a carrier supporting both PMCH and POSCH or not. Besides the additional TDOA-RS reference signal, an additional synchronization signal (TDOA-sync) may also be included to improve the hearability of neighbor cells. | 11-24-2011 |
20110299617 | X-mimo systems with multi-transmitters and multi-receivers - A method and apparatus for transmitting and receiving a wireless transmission of a plurality of data streams in a wireless communication system having a plurality of nodes is disclosed. Each node has multiple antennas. The method involves receiving first and second data streams from respective first and second nodes at a receiver node, causing the receiver node to generate a receive filter for decoding each of the received data streams, and causing the receiver node to transmit receive filter information for each of the first and second data streams, the receive filter information facilitating precoding of the first and second data streams for simultaneous transmission within a common frequency band to the receiver node. | 12-08-2011 |
20110306291 | ENABLING DOWNLINK TRANSPARENT RELAY IN A WIRELESS COMMUNICATIONS NETWORK - Methods and apparatus are described for enabling downlink transparent relay in a wireless communication network. In a wireless communications network, a base station and a mobile station may communicate with each other via a relay station, as needed. Transparent relay may allow for relay communication between a base station and a mobile station although the mobile station is unaware of the relay station. However, non-contiguous transmission of a relay station may lead to channel quality measurement and channel estimation degradation during downlink transparent relay. According to some aspects, a base station may schedule a mobile station to a transmission mode that utilizes dedicated pilot signals for downlink transparent relay, and a relay station may transmit data and dedicated pilot signals over the same channel resources as the base station. According to some aspects, the relay station may null common pilot signals transmitted by the base station. | 12-15-2011 |
20110310725 | SOFT HANDOFF IN OFDMA SYSTEM - Soft handoff in an OFDMA system is disclosed. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone has subcarriers with a subchannel definition, for example, an identical permutation. | 12-22-2011 |
20110310846 | SOFT HANDOFF IN OFDMA SYSTEM - Soft handoff in an OFDMA system is disclosed. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone has subcarriers with a subchannel definition, for example, an identical permutation. | 12-22-2011 |
20110310847 | SOFT HANDOFF IN OFDMA SYSTEM - Soft handoff in an OFDMA system is disclosed. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone has subcarriers with a subchannel definition, for example, an identical permutation. | 12-22-2011 |
20110310848 | SOFT HANDOFF IN OFDMA SYSTEM - Soft handoff in an OFDMA system is disclosed. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone has subcarriers with a subchannel definition, for example, an identical permutation. | 12-22-2011 |
20120020326 | METHOD AND APPARATUS FOR EFFECTING A HANDOFF IN A FREQUENCY-DIVISION MULTIPLEX NETWORK - In a frequency division multiplex network, a method involves employing spread-spectrum communication in addition to frequency-division multiplexing for facilitating handoffs. A portion of the total transmission resources is designated for spread-spectrum frequency division multiplexed signals. A communication between a base station and a mobile station takes place over a transmission resource block in the reserved designated portion at the moment of handoff and uses spread-spectrum frequency-division signals. A base station receiving the handoff can communicate over the transmission resource block even if it is already communicating over the transmission resource block since the communication is spread-spectrum encoded. | 01-26-2012 |
20120020403 | MULTI-ANTENNA SCHEDULING SYSTEM AND METHOD - A wireless communication method and system using virtual MIMO (“V-MIMO”) are provided. Post processing signal to interference and noise ratios (“SINR”) for a plurality of signals corresponding to a plurality of mobile terminals arranged as a V-MIMO group are estimated. The one of the plurality of mobile terminals having the highest post processing SINR is selected. Wireless communication for the selected mobile terminal is scheduled. The signal corresponding to the selected mobile terminal is cancelled. Post processing signal to interference and noise ratios (“SINR”) for the signals corresponding to the remaining mobile terminals is re-estimated. The one of the remaining mobile terminals having the highest post processing SINR is selected. Wireless communication for the selected remaining mobile terminal is scheduled. | 01-26-2012 |
20120020434 | TRANSMISSION USING COMMON AND DEDICATED PILOTS - A method, system, base station and wireless terminal are provided for transmission of a set of mixed pilots that includes both common and dedicated pilots. The method includes selecting a number D of dedicated pilots having regard to performance of the communication link, D≧0, selecting a first pre-coder for pre-coding D dedicated pilots based on some criteria, performing a first pre-coding of the D dedicated pilots with the first pre-coder to produce a set of pre-coded dedicated pilots, performing a second pre-coding of the set of pre-coded dedicated pilots and a set of common pilots to produce a set of mixed pilots, and transmitting data from the transmitter on the communication link with the set of mixed pilots. | 01-26-2012 |
20120027136 | SYSTEM ACCESS AND SYNCHRONIZATION METHODS FOR MIMO OFDM COMMUNICATIONS SYSTEMS AND PHYSICAL LAYER PACKET AND PREAMBLE DESIGN - A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame. | 02-02-2012 |
20120039419 | X-MIMO SYSTEMS WITH MULTI-TRANSMITTERS AND MULTI-RECEIVERS - A method and apparatus for transmitting and receiving a wireless transmission of a plurality of data streams in a wireless communication system having a plurality of nodes is disclosed. Each node has multiple antennas. The method involves receiving first and second data streams from respective first and second nodes at a receiver node, causing the receiver node to generate a receive filter for decoding each of the received data streams, and causing the receiver node to transmit receive filter information for each of the first and second data streams, the receive filter information facilitating precoding of the first and second data streams for simultaneous transmission within a common frequency band to the receiver node. | 02-16-2012 |
20120044849 | POWER ALLOCATION IN CLOSED-LOOP DOWNLINK COOPERATIVE MULTIPLE POINT (COMP) TRANSMISSION - Techniques for power allocation among a plurality of network nodes in a communication network for cooperative downlink transmission to a mobile terminal are provided. Cooperative transmission to a mobile terminal is done in a selected one of a plurality of frequency bands allocated for cooperative downlink transmission, wherein each network node has a respective predetermined frequency band transmission power level for each of the plurality of frequency bands allocated for cooperative downlink transmission. Selection of the frequency band on which the mobile terminal will be cooperatively transmitted to is based on channel state information indicative of the channel between the mobile terminal and each of the network nodes and, for each of the frequency bands, the respective plurality of predetermined frequency band transmission power levels corresponding to the plurality of network nodes. | 02-23-2012 |
20120063409 | SYSTEMS AND METHODS FOR UPLINK SIGNALLING - Methods, base stations and access terminals for uplink signalling are provided. Resource request channel characteristics such as location in time-frequency, sequence, time slot, are assigned to each access terminal to distinguish their resource requests from the resource requests of other access terminals. Access terminals make requests using a resource request on a resource request channel having the assigned characteristics. The base station can then determine which access terminal transmitted the resource request based on the resource request channel characteristics of the resource request channel upon which the resource request was received. The base station then transmits a response to the request which may for example be a new resource allocation, a default allocation or a renewal of a previous allocation. | 03-15-2012 |
20120087296 | NETWORK-RELAY SIGNALING FOR DOWNLINK TRANSPARTENT RELAY - A method of providing downlink retransmissions to a mobile station in a wireless communication network, the wireless communication network comprising a base station communicatively linked to a transparent relay station, the method comprising: at the base station: receiving a request for a retransmission from the mobile station; scheduling resources for the retransmission; signalling scheduling information for the retransmission to the transparent relay station via a control link; at the transparent relay station: receiving said scheduling information for the retransmission on the control link; and sending the retransmission to the mobile station in a retransmit subframe on a retransmit frequency band. | 04-12-2012 |
20120087335 | Multi-site mimo cooperation in cellular network - In a cellular communications network comprising a plurality of transmitting sites wherein each transmitting site comprises at least one antenna, a method of serving a given data stream to a target mobile terminal, comprising: designating at least two of the plurality of transmitting sites as cooperating sites; assigning tones to each transmitting site from a sub-band associated with the cooperating sites; dividing the data stream into at least two sub-data streams, each of the sub-data streams for transmission over selected tones; and interlacing tones of the cooperating sites in accordance with a selected one of a time switching and a frequency switching transmit diversity technique. | 04-12-2012 |
20120087394 | METHODS AND SYSTEMS FOR OFDM USING CODE DIVISION MULTIPLEXING - In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions. | 04-12-2012 |
20120087442 | DESIGN ASPECTS TO SUPPORT LTE-A DOWNLINK HI-ORDER MIMO - A method of operation of a MIMO transmitter, in a cellular network supporting both legacy standard-compliant mobile terminals and next generation standard-compliant mobile terminals, the method comprising defining a matrix of resource blocks within an information channel of the cellular network, wherein each resource block corresponds to a region of subcarriers of a transmission timeslot at a given frequency subband; assigning a first set of reference signals (RSs) for the legacy standard-compliant mobile terminals to resource blocks at specific locations within the matrix to be transmitted by the MIMO transmitter, the specific locations being defined by, the legacy standard; and assigning a second set of RSs for the next-generation standard-compliant mobile terminals to other resource blocks within the matrix to be transmitted by the MIMO transmitter. | 04-12-2012 |
20120106410 | MODULATION DIVISION MULTIPLE ACCESS - The present invention employs hierarchical modulation to simultaneously transmit information on different modulation layers using a carrier RF signal. Initially, first data to be transmitted is assigned to a first modulation layer and second data is assigned to a second modulation layer. In one embodiment of the present invention, the first and second data are assigned based on reliability criteria. The first and second modulation layers are hierarchical modulation layers of the carrier RF signal. Once assigned, the first data is transmitted using the first modulation layer of the carrier RF signal and the second data is transmitted using the second modulation layer of the carrier RF signal. In one embodiment of the present invention, information may be transmitted to one end user using one modulation layer, and information may be transmitted to a different end user using a different modulation layer. | 05-03-2012 |
20120121047 | COMMUNICATION SIGNAL DECODING AND SOFT DEMAPPING METHODS AND SYSTEMS - Symbol detection and soft dempapping methods and systems are provided. Individual subset symbol detection according to an embodiment of the invention involves identifying a search subset of a transmission symbol set for a transmission symbol. For each other transmission symbol in communication signals, multiple search subsets of the transmission symbol set are identified. The multiple search subsets include respective search subsets based on each transmission symbol in either the search subset for the first identified one of the transmission symbols or each of the multiple search subsets identified for a different one of the other transmission symbols. Symbol detection errors may be detected by identifying competing symbols and computing competing distances. Soft demapping may be provided by calculating soft decision results based on detected symbols and weighting the soft decision result. | 05-17-2012 |
20120163282 | Relay Techniques Suitable for User Equipment in Downlink - The present invention provides a solution to improve coverage and cell edge performance in a mobile user communication system is the use of fixed relays, which are pieces of infrastructure without a wired backhaul connection. The relays transmit or “relay” downlink messages between the base station (BS) and mobile stations (MSs) through a multi-hop communication. The present invention is a method and system for supporting a multiple user mobile broadband communication network that includes relay techniques suitable for user equipment in the downlink communication to the user equipment. | 06-28-2012 |
20120176960 | SYSTEM AND METHOD FOR UNBALANCED RELAY-BASED WIRELESS COMMUNICATIONS - A method and system for wireless communication with a mobile device in which wireless communication is established with the mobile device. A base station is used to transmit directly to the mobile device in a downlink direction. A relay node is used to transmit to the base station communications received in an uplink direction from the mobile station. The relay node relays at least a portion of the uplink traffic received from the mobile station to the base station. | 07-12-2012 |
20120188881 | Adaptive Transmission Systems and Methods - Abstract Spatial multiplexing and transmit diversity can improve the capacity of a wireless communication system. The system and method adapts communication schemes for communication systems with multiple antennas utilizing at least two transmission modes. The at least two transmission modes can, but are not necessarily, used for uplink communications. The two transmission modes may be chosen from the group consisting of a single antenna mode, a diversity mode a spatial multiplexed mode and a mixed diversity and spatial multiplexed mode. The at least two transmission modes may involve adaptation among multiple transmitters. At least one receiver may indicate a transmission mode to be used by a transmitter for a subsequent transmission. A transmitter may determine a transmission mode to be used for a subsequent transmission. The transmission mode can be based on channel sounding. | 07-26-2012 |
20120188946 | SYSTEM AND METHOD FOR FREQUENCY DIVISION MULTIPLE ACCESS COMMUNICATIONS - A method and system for wireless frequency division multiple access communications in the uplink and/or downlink directions. A first time duration for transmission of a data payload block is established, and the transmission is processed using a first frequency domain or a time domain. A second time duration for transmission of at least one pilot block is established, and the transmission is processed using a second frequency domain or the time domain, the second time duration is not greater than the first time duration. | 07-26-2012 |
20120207118 | CODING INFORMATION FOR COMMUNICATION OVER AN ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS (OFDMA)-BASED WIRELESS LINK - In a wireless access network, a transmitter provides a pool of sequences having a reduced peak-to-average power ratio. Information to be transmitted is mapped to a selected at least one of the pool of sequences. The selected at least one sequence is transmitted over an orthogonal frequency division multiple access (OFDMA)-based wireless link of the wireless access network. | 08-16-2012 |
20120219093 | METHOD AND APPARATUS FOR CHANNEL QUALITY MEASUREMENTS - A method and apparatus for measuring channel quality over which has been transmitted a sequence of symbols produced by encoding and constellation mapping a source data element sequence. A sequence of received symbols is received over the channel. The sequence of received symbols is de-mapped based on a first channel quality indicator previously transmitted to a transmitter of the sequence of symbols. The de-mapped symbols are decoded to produce a decoded output sequence. In some embodiments, the decoding may be based on the first channel quality indicator. The decoded output sequence is re-encoded to produce a re-encoded output sequence. The de-mapped symbols are correlated with the re-encoded output sequence to produce a second channel quality indicator. The second channel quality indicator is transmitted to the transmitter to adaptively select a type of mapping based on the second channel quality indicator. | 08-30-2012 |
20120224659 | PILOT DESIGN FOR WIRELESS SYSTEM - The description herein relates to pilot designs for an Orthogonal Frequency Division Multiplexing (OFDM) based communication system. In the preferred embodiment, the communication system is one operating according to the IEEE 802.16m, or WiMax, standard. In general, an OFDM transmitter operates to insert pilot symbols into a resource of a transmit frame according to a predetermined staggered pilot symbol pattern defining pilot symbol locations within the resource of the transmit frame. The predetermined pilot symbol pattern is defined such that pilot symbols are located at or near time boundaries of the resource, at or near frequency boundaries of the resource, or both. By doing so, when generating a channel estimate for the communication channel between the OFDM transmitter and an OFDM receiver based on the pilot symbols, extrapolations needed to estimate the channel near the boundaries of the resource are optimized, thereby improving overall channel estimation accuracy. | 09-06-2012 |
20120230233 | CLOSED-LOOP MIMO SYSTEMS AND METHODS - Methods, devices and systems are provided for transmitting and receiving MIMO signals. In one embodiment, transmitting_of the MIMO signals involves pre-coding each of at least two data symbols using a respective pre-coding codeword to preclude a corresponding plurality of pre-coded data symbols. A respective signal is transmitted from each of a plurality of antennas, the respective signal including one of the pre-coded signals and at least one pilot for use in channel estimation. The signals collectively further include at least one beacon pilot vector consisting of a respective beacon pilot per antenna, the beacon pilot vector containing contents known to a receiver for use by the receiver in determining the codeword used to pre-code the at least one data signal. | 09-13-2012 |
20120243626 | SYSTEM ACCESS AND SYNCHRONIZATION METHODS FOR MIMO OFDM COMMUNICATIONS SYSTEMS AND PHYSICAL LAYER PACKET AND PREAMBLE DESIGN - A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame. | 09-27-2012 |
20120250787 | SYSTEM ACCESS AND SYNCHRONIZATION METHODS FOR MIMO OFDM COMMUNICATIONS SYSTEMS AND PHYSICAL LAYER PACKET AND PREAMBLE DESIGN - A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame. | 10-04-2012 |
20120281676 | SOFT HANDOFF IN OFDMA SYSTEM - Soft handoff in an OFDMA system is disclosed. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone has subcarriers with a subchannel definition, for example, an identical permutation. | 11-08-2012 |
20120307928 | SIGNALING AND CHANNEL ESTIMATION FOR UPLINK TRANSMIT DIVERSITY - In a method of transmitting a data stream from a transmitter in a multiple-input-multiple-output (MIMO) wireless communication system, where the transmitter comprises a plurality of transmit antennas, a discrete Fourier transform (DFT) is applied to the data stream to generate a plurality of symbol sequences; symbols of a first symbol sequence from the plurality of symbol sequences are paired with symbols of a second symbol sequence from the plurality of symbol sequences to generate a plurality of symbol pairs, wherein the pairing results in an orphan symbol; a space-time block code (STBC) is applied to the symbol pairs to generate a plurality of sets of STBC symbols, each set of STBC symbols being associated with a corresponding one of the plurality of antennas; a cyclic delay diversity (CDD) operation is applied to the orphan symbol to generate a plurality of CDD symbols, each CDD symbol being associated with a corresponding one of the plurality of antennas; and each one of the antennas transmits the corresponding set of STBC symbols and the corresponding CDD symbol. | 12-06-2012 |
20120307930 | Scattered Pilot Pattern And Channel Estimation Method For MIMO-OFDM Systems - A method and apparatus are provided for reducing the number of pilot symbols within a MIMO-OFDM communication system, and for improving channel estimation within such a system. For each transmitting antenna in an OFDM transmitter, pilot symbols are encoded so as to be unique to the transmitting antenna. The encoded pilot symbols are then inserted into an OFDM frame to form a diamond lattice, the diamond lattices for the different transmitting antennae using the same frequencies but being offset from each other by a single symbol in the time domain. At the OFDM receiver, a channel response is estimated for a symbol central to each diamond of the diamond lattice using a two-dimensional interpolation. The estimated channel responses are smoothed in the frequency domain. The channel responses of remaining symbols are then estimated by interpolation in the frequency domain. | 12-06-2012 |
20120327905 | SOFT HANDOFF IN OFDMA SYSTEM - Soft handoff in an OFDMA system is disclosed. If the pilot signal strength for a base station exceeds the defined threshold, the base station is added to an active set list. Subcarriers in a plurality of orthogonal frequency division multiplexing (OFDM) symbols are divided and allocated into subchannels. The OFDM symbols are divided and multiplexed. A soft handoff zone with a first dimension of the subchannels and a second dimension of the divided and multiplexed OFDM symbols is defined. The soft handoff zone has subcarriers with a subchannel definition, for example, an identical permutation. | 12-27-2012 |
20120328040 | Detecting the Number of Transmit Antennas in a Base Station - Data is scrambled at a transmitter according to one of a number of predetermined scrambling sequences which are associated with a particular one of a number of predetermined transmit antenna diversity schemes (i.e., a specific number of transmit antenna ports). Received data is decoded using one or more of the known transmit antenna diversity schemes and the scrambled data is descrambled according to a corresponding descrambling sequence (related to the scrambling sequence). Based on the descrambled data, the receiver determines which transmit antenna diversity scheme (i.e., the number of antenna ports) is used by the transmitter. In one specific embodiment, CRC parity data is scrambled in the transmitter and the receiver descrambles the recovered CRC parity data according to a descrambling sequence, computes CRC parity data from the received data, and compares the descrambled CRC parity data to the newly computed CRC parity data. | 12-27-2012 |
20120331366 | Method and System for Retransmitting Data Packets in a Space-Time Coded Radio Communication System - A method and system are provided for minimizing errors by retransmitting packets in a multiple-input-multiple-output (MIMO) space-time coded packet radio. A packet is transmitted using a first STC code mapping, the mapping including well-known symbol operations, and optional signal weighting. When transmission errors are detected the packet is re-transmitted using STC code mappings selected in turn from a deterministic sequence of STC code mappings. The STC code mappings are chosen in accordance with one or more principles. | 12-27-2012 |
20130003649 | METHODS AND SYSTEMS FOR WIRELESS NETWORKS WITH RELAYS - Methods and systems are provided for use with wireless networks having one or more cell in which each cell includes a base station (BS), at least one relay station (RS) and at least one mobile station (MS). The at least one relay station can be used as an intermediate station for providing communication between the BS and MS. Methods are provided for allocating OFDM resources for communicating between the BS, RS and/or MS for example dividing transmission resources into uplink and downlink transmissions and methods of inserting pilot symbols into transmission resources used by the RS. In some embodiments on the invention, the methods are consistent and/or can be used in conjunction with existing standards such as 802.16e. | 01-03-2013 |
20130003893 | Detecting the Number of Transmit Antennas in a Base Station - Data is scrambled at a transmitter according to one of a number of predetermined scrambling sequences which are associated with a particular one of a number of predetermined transmit antenna diversity schemes (i.e., a specific number of transmit antenna ports). Received data is decoded using one or more of the known transmit antenna diversity schemes and the scrambled data is descrambled according to a corresponding descrambling sequence (related to the scrambling sequence). Based on the descrambled data, the receiver determines which transmit antenna diversity scheme (i.e., the number of antenna ports) is used by the transmitter. In one specific embodiment, CRC parity data is scrambled in the transmitter and the receiver descrambles the recovered CRC parity data according to a descrambling sequence, computes CRC parity data from the received data, and compares the descrambled CRC parity data to the newly computed CRC parity data. | 01-03-2013 |
20130010679 | METHODS AND SYSTEMS FOR WIRELESS NETWORKS WITH RELAYS - Methods and systems are provided for use with wireless networks having one or more cell in which each cell includes a base station (BS), at least one relay station (RS) and at least one mobile station (MS). The at least one relay station can be used as an intermediate station for providing communication between the BS and MS. Methods are provided for an RS to initially access the network, access of the RS by MSs initially accessing the network, methods of allocating OFDM resources for communicating between the BS, RS and/or MS for example dividing transmission resources into uplink and downlink transmissions, and methods of inserting pilot symbols into transmission resources used by the RS. In some embodiments on the invention, the methods are consistent and/or can be used in conjunction with existing standards such as 802.16e. | 01-10-2013 |
20130010729 | MULTIPLEXING SCHEMES FOR OFDMA - Methods and systems are provided for allocating resources including VoIP (voice over Internet Protocol) and Non-VoIP resources. In some embodiments, multiplexing schemes are provided for use with OFDMA (orthogonal frequency division multiplexing access) systems, for example for use in transmitting VoIP traffic. In some embodiments, various HARQ (Hybrid Automatic request) techniques are provided for use with OFDMA systems. In various embodiments, there are provided methods and systems for dealing with issues such as Handling non-full rate vocoder frames, VoIP packet jitter handling, VoIP capacity increasing schemes, persistent and non-persistent assignment of resources in OFDMA systems. | 01-10-2013 |
20130010808 | SCATTERED PILOT PATTERN AND CHANNEL ESTIMATION METHOD FOR MIMO-OFDM SYSTEMS - Methods and apparatus are provided for inserting data symbols and pilot symbols in an OFDM (orthogonal frequency division multiplexing) transmission resource utilizing frequency hopping patterns for the data symbols and/or the pilot symbols. Data symbols and pilot symbols are allocated for down link (base station to mobile station) and up link (mobile station to bases station) transmission resources in a two-dimensional time-frequency pattern. For each antenna of a MIMO-OFDM (multiple input multiple output OFDM) communication system, pilot symbols are inserted in a scattered pattern in time-frequency and data symbols are inserted in an identical frequency-hopping pattern in time-frequency as that of other antennas. | 01-10-2013 |
20130010840 | X-MIMO Systems with Multi-Transmitters and Multi-Receivers - A method and apparatus for transmitting and receiving a wireless transmission of a plurality of data streams in a wireless communication system having a plurality of nodes is disclosed. Each node has multiple antennas. The method involves receiving first and second data streams from respective first and second nodes at a receiver node, causing the receiver node to generate a receive filter for decoding each of the received data streams, and causing the receiver node to transmit receive filter information for each of the first and second data streams, the receive filter information facilitating precoding of the first and second data streams for simultaneous transmission within a common frequency band to the receiver node. | 01-10-2013 |
20130010887 | SCATTERED PILOT PATTERN AND CHANNEL ESTIMATION METHOD FOR MIMO-OFDM SYSTEMS - Methods and apparatus are provided for inserting data symbols and pilot symbols in an OFDM (orthogonal frequency division multiplexing) transmission resource utilizing frequency hopping patterns for the data symbols and/or the pilot symbols. Data symbols and pilot symbols are allocated for down link (base station to mobile station) and up link (mobile station to bases station) transmission resources in a two-dimensional time-frequency pattern. For each antenna of a MIMO-OFDM (multiple input multiple output OFDM) communication system, pilot symbols are inserted in a scattered pattern in time-frequency and data symbols are inserted in an identical frequency-hopping pattern in time-frequency as that of other antennas. | 01-10-2013 |
20130010893 | X-MIMO Systems with Multi-Transmitters and Multi-Receivers - A method and apparatus for transmitting and receiving a wireless transmission of a plurality of data streams in a wireless communication system having a plurality of nodes is disclosed. Each node has multiple antennas. The method involves receiving first and second data streams from respective first and second nodes at a receiver node, causing the receiver node to generate a receive filter for decoding each of the received data streams, and causing the receiver node to transmit receive filter information for each of the first and second data streams, the receive filter information facilitating precoding of the first and second data streams for simultaneous transmission within a common frequency band to the receiver node. | 01-10-2013 |
20130012119 | ENABLING DOWNLINK TRANSPARENT RELAY IN A WIRELESS COMMUNICATIONS NETWORK - Methods and apparatus are described for enabling downlink transparent relay in a wireless communication network. In a wireless communications network, a base station and a mobile station may communicate with each other via a relay station, as needed. Transparent relay may allow for relay communication between a base station and a mobile station although the mobile station is unaware of the relay station. However, non-contiguous transmission of a relay station may lead to channel quality measurement and channel estimation degradation during downlink transparent relay. According to some aspects, a base station may schedule a mobile station to a transmission mode that utilizes dedicated pilot signals for downlink transparent relay, and a relay station may transmit data and dedicated pilot signals over the same channel resources as the base station. According to some aspects, the relay station may null common pilot signals transmitted by the base station. | 01-10-2013 |
20130016603 | MULTIPLEXING SCHEMES FOR OFDMA - Methods and systems are provided for allocating resources including VoIP (voice over Internet Protocol) and Non-VoIP resources. In some embodiments, multiplexing schemes are provided for use with OFDMA (orthogonal frequency division multiplexing access) systems, for example for use in transmitting VoIP traffic. In some embodiments, various HARQ (Hybrid Automatic request) techniques are provided for use with OFDMA systems. In various embodiments, there are provided methods and systems for dealing with issues such as Handling non-full rate vocoder frames, VoIP packet jitter handling, VoIP capacity increasing schemes, persistent and non-persistent assignment of resources in OFDMA systems. | 01-17-2013 |
20130016650 | METHODS AND SYSTEMS FOR WIRELESS NETWORKS WITH RELAYS - Methods and systems are provided for use with wireless networks having one or more cell in which each cell includes a base station (BS), at least one relay station (RS) and at least one mobile station (MS). The at least one relay station can be used as an intermediate station for providing communication between the BS and MS. Methods are provided for allocating OFDM resources for communicating between the BS, RS and/or MS for example dividing transmission resources into uplink and downlink transmissions and methods of inserting pilot symbols into transmission resources used by the RS. In some embodiments on the invention, the methods are consistent and/or can be used in conjunction with existing standards such as 802.16e. | 01-17-2013 |
20130016693 | SCATTERED PILOT PATTERN AND CHANNEL ESTIMATION METHOD FOR MIMO-OFDM SYSTEMS - Methods and apparatus are provided for inserting data symbols and pilot symbols in an OFDM (orthogonal frequency division multiplexing) transmission resource utilizing frequency hopping patterns for the data symbols and/or the pilot symbols. Data symbols and pilot symbols are allocated for down link (base station to mobile station) and up link (mobile station to bases station) transmission resources in a two-dimensional time-frequency pattern. For each antenna of a MIMO-OFDM (multiple input multiple output OFDM) communication system, pilot symbols are inserted in a scattered pattern in time-frequency and data symbols are inserted in an identical frequency-hopping pattern in time-frequency as that of other antennas. | 01-17-2013 |
20130022020 | MULTIPLEXING SCHEMES FOR OFDMA - Methods and systems are provided for allocating resources including VoIP (voice over Internet Protocol) and Non-VoIP resources. In some embodiments, multiplexing schemes are provided for use with OFDMA (orthogonal frequency division multiplexing access) systems, for example for use in transmitting VoIP traffic. In some embodiments, various HARQ (Hybrid Automatic request) techniques are provided for use with OFDMA systems. In various embodiments, there are provided methods and systems for dealing with issues such as Handling non-full rate vocoder frames, VoIP packet jitter handling, VoIP capacity increasing schemes, persistent and non-persistent assignment of resources in OFDMA systems. | 01-24-2013 |
20130028122 | METHODS AND SYSTEMS FOR WIRELESS NETWORKS WITH RELAYS - Methods and systems are provided for use with wireless networks having one or more cell in which each cell includes a base station (BS), at least one relay station (RS) and at least one mobile station (MS). The at least one relay station can be used as an intermediate station for providing communication between the BS and MS. Methods are provided for an RS to initially access the network, access of the RS by MSs initially accessing the network, methods of allocating OFDM resources for communicating between the BS, RS and/or MS for example dividing transmission resources into uplink and downlink transmissions, and methods of inserting pilot symbols into transmission resources used by the RS. In some embodiments on the invention, the methods are consistent and/or can be used in conjunction with existing standards such as 802.16e. | 01-31-2013 |
20130034007 | Systems and Methods for OFDM Channelization - Systems and methods for OFDM channelization are provided that allow for the co-existence of sub-band channels and diversity channels. Methods of defining diversity sub-channels and sub-band sub-channels are provided, and systematic channel definition and labeling schemes are provided. | 02-07-2013 |
20130034049 | Modulation Division Multiple Access - The present invention employs hierarchical modulation to simultaneously transmit information on different modulation layers using a carrier RF signal. Initially, first data to be transmitted is assigned to a first modulation layer and second data is assigned to a second modulation layer. In one embodiment of the present invention, the first and second data are assigned based on reliability criteria. The first and second modulation layers are hierarchical modulation layers of the carrier RF signal. Once assigned, the first data is transmitted using the first modulation layer of the carrier RF signal and the second data is transmitted using the second modulation layer of the carrier RF signal. In one embodiment of the present invention, information may be transmitted to one end user using one modulation layer, and information may be transmitted to a different end user using a different modulation layer. | 02-07-2013 |
20130039388 | COMMUNICATION SYSTEMS AND METHODS - In accordance with embodiments, a communication system includes a first device and a second device in communication with the first device. The second device has at least a first pair and a second pair of antennas. The second device spreads a communication bit by a predetermined spreading factor and forms a first set of spatial block codes in frequency domain based on the spread communication bit. The first set of spatial block codes being consecutively transmitted on one of the first and second pairs of antennas. | 02-14-2013 |
20130064171 | Ranging Regions for Wireless Communication Relay Stations - One embodiment of the present invention provides a unique ranging technique in wireless communication environments that employ relay stations associated with a base station. Each relay station, and optionally the base station itself, can be allocated a unique ranging region having unique ranging resources that may be used by a mobile station to initiate a ranging function with the corresponding relay station or base station. | 03-14-2013 |
20130077468 | Preambles in OFDMA System - The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-1 and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems. | 03-28-2013 |
20130077469 | Preambles in OFDMA System - The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-I and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems. | 03-28-2013 |
20130083718 | System and Method for Spatial Multiplexing-Based OFDM Broadcast/Multicast Transmission - A method of OFDM transmission/reception comprising: transmitting broadcast/multicast signals on a first antenna and unicast signals on a second antenna; segregating broadcast/multicast sub-channelization from unicast channels sub-channelization based on FDM(frequency division multiplexing)/TDM (time division multiplexing) sub-channelization. | 04-04-2013 |
20130107857 | Pilot Scheme for a MIMO Communication System | 05-02-2013 |
20130122948 | Multi-Antenna Scheduling System and Method - A wireless communication method and system using virtual MIMO (“V-MIMO”) are provided. Post processing signal to interference and noise ratios (“SINR”) for a plurality of signals corresponding to a plurality of mobile terminals arranged as a V-MIMO group are estimated. The one of the plurality of mobile terminals having the highest post processing SINR is selected. Wireless communication for the selected mobile terminal is scheduled. The signal corresponding to the selected mobile terminal is cancelled. Post processing signal to interference and noise ratios (“SINR”) for the signals corresponding to the remaining mobile terminals is re-estimated. The one of the remaining mobile terminals having the highest post processing SINR is selected. Wireless communication for the selected remaining mobile terminal is scheduled. | 05-16-2013 |
20130128820 | METHOD AND APPARATUS FOR DETERMINING CHANNEL QUALITY INDEX IN MULTIPLE USER-MIMO COMMUNICATION NETWORKS - In order to minimize the control signaling overhead associated with transmitting CQI data from mobile stations to base stations in wireless communication networks supporting MU-MIMO, the CQI during MU-MIMO operation is estimated based on SU-MIMO CQI data, mobile station geometry data, and mobile station PMI (Precoding Matrix Index) data. More particularly, the base station maintains and updates a knowledge pool that correlates geometry data and learned impact of interfering precoder data to degradation of CQI values responsive to switching from SU-MIMO operation to MU-MIMO operations. Then, when the base station switches from SU-MIMO operation to MU-MIMO operation, it consults the knowledge pool to predict the degradation in CQI and subtracts them from the known, pre-switching SU-MIMO CQI feedback data for each relevant mobile station to predict the post-switching MU-MIMO CQIs for that mobile station. | 05-23-2013 |
20130128997 | Adaptive Two-Dimensional Channel Interpolation - A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency). | 05-23-2013 |
20130136205 | Adaptive Two-Dimensional Channel Interpolation - A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency). | 05-30-2013 |
20130223553 | Scattered Pilot Pattern And Channel Estimation Method For MIMO-OFDM Systems - A method and apparatus are provided for reducing the number of pilot symbols within a MIMO-OFDM communication system, and for improving channel estimation within such a system. For each transmitting antenna in an OFDM transmitter, pilot symbols are encoded so as to be unique to the transmitting antenna. The encoded pilot symbols are then inserted into an OFDM frame to form a diamond lattice, the diamond lattices for the different transmitting antennae using the same frequencies but being offset from each other by a single symbol in the time domain. At the OFDM receiver, a channel response is estimated for a symbol central to each diamond of the diamond lattice using a two-dimensional interpolation. The estimated channel responses are smoothed in the frequency domain. The channel responses of remaining symbols are then estimated by interpolation in the frequency domain. | 08-29-2013 |
20130265930 | Detecting the Number of Transmit Antennas in a Base Station - Data is scrambled at a transmitter according to one of a number of predetermined scrambling sequences which are associated with a particular one of a number of predetermined transmit antenna diversity schemes (i.e., a specific number of transmit antenna ports). Received data is decoded using one or more of the known transmit antenna diversity schemes and the scrambled data is descrambled according to a corresponding descrambling sequence (related to the scrambling sequence). Based on the descrambled data, the receiver determines which transmit antenna diversity scheme (i.e., the number of antenna ports) is used by the transmitter. In one specific embodiment, CRC parity data is scrambled in the transmitter and the receiver descrambles the recovered CRC parity data according to a descrambling sequence, computes CRC parity data from the received data, and compares the descrambled CRC parity data to the newly computed CRC parity data. | 10-10-2013 |
20130272458 | Communication Signal Decoding and Soft Demapping - Symbol detection and soft demapping methods and systems are provided. Individual subset symbol detection according to one or more embodiments involves identifying a search subset of a transmission symbol set for a transmission symbol. For each other transmission symbol in communication signals, multiple search subsets of the transmission symbol set are identified. The multiple search subsets include respective search subsets based on each transmission symbol in either the search subset for the first identified one of the transmission symbols or each of the multiple search subsets identified for a different one of the other transmission symbols. Symbol detection errors may be detected by identifying competing symbols and computing competing distances. Soft demapping may be provided by calculating soft decision results based on detected symbols and weighting the soft decision result. | 10-17-2013 |
20130287138 | Pilot Design for OFDM Systems with Four Transmit Antennas - Pilot, preamble and midamble patterns are provided that are particularly suited for four transmit antenna OFDM systems. Pilots are inserted in a scattered manner for each of the four antennas, either uncoded, space-time coded in pairs, space-time frequency coded in pairs, or space-time-frequency coded. | 10-31-2013 |
20130301400 | System Access and Synchronization Methods for MIMO OFDM Communications Systems and Physical Layer Packet and Preamble Design - A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame. | 11-14-2013 |
20130301510 | Method and System for Allocating Media Access Control Layer Resources in a Wireless Communication Environment - A method and system for allocating shareable wireless transmission resources. A resource pool is established. The resource pool is divided into a plurality of physical layer allocation units usable for wirelessly transmitting control information and traffic data. The allocation units are assigned at the media access control layer for the wireless transmission of the control information and traffic data. The system and method of the present invention also allows mobile stations to be dynamically grouped into multicast groupings to reduce system overhead resource requirements. | 11-14-2013 |
20130301513 | Multimedia Broadcast Multicast Service (MBMS) Utilizing Spatial Multiplexing - Systems and methods are disclosed herein for an enhanced Multimedia Broadcast Multicast Service (MBMS) in a wireless communications network. In one embodiment, a number of base stations in a MBMS zone, or broadcast region, accommodate both Spatial Multiplexing (SM) enabled user elements and non-SM enabled user elements. In another embodiment, a number of base stations form a MBMS zone, or broadcast region, where the MBMS zone is sub-divided into an SM zone and a non-SM zone. In another embodiment, the wireless communications network includes multiple MBMS zones. For each MBMS zone, base stations serving the MBMS zone transmit an MBMS zone identifier (ID) for the MBMS zone. The MBMS zone ID may be used by a user element for decoding and/or to determine when to perform a handoff from one MBMS zone to another. | 11-14-2013 |
20130301685 | Methods and Systems for OFDM using Code Division Multiplexing - In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions. | 11-14-2013 |
20130301761 | Methods and Systems for Orthogonal Frequency Division Multiplexing (OFDM) Multiple Zone Partitioning - Aspects of the invention include methods and devices for inserting data and pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) frames having a time domain and a frequency domain. A method involves inserting in at least one zone of a first type a two dimensional array of data and pilot symbols in time and frequency and inserting in at least one zone of a second type a two dimensional array of data and pilot symbols in time and frequency. In some implementations the zone of the first type comprises common pilot symbols that can be detected by all receivers receiving the OFDM frame. In some implementations the zone of the second type comprises dedicated pilot symbols that are only detectable by a receiver that is aware of pre-processing used to encode the dedicated pilot symbols. | 11-14-2013 |
20130329818 | PILOT DESIGN FOR WIRELESS SYSTEM - The description herein relates to pilot designs for an Orthogonal Frequency Division Multiplexing (OFDM) based communication system. In at least one embodiment, the communication system is one operating according to the IEEE 802.16m, or WiMax, standard. In general, an OFDM transmitter operates to insert pilot symbols into a resource of a transmit frame according to a predetermined staggered pilot symbol pattern defining pilot symbol locations within the resource of the transmit frame. The predetermined pilot symbol pattern is defined such that pilot symbols are located at or near time boundaries of the resource, at or near frequency boundaries of the resource, or both. By doing so, when generating a channel estimate for the communication channel between the OFDM transmitter and an OFDM receiver based on the pilot symbols, extrapolations needed to estimate the channel near the boundaries of the resource are optimized, thereby improving overall channel estimation accuracy. | 12-12-2013 |
20140010268 | PILOT DESIGN FOR WIRELESS SYSTEM - The description herein relates to pilot designs for an Orthogonal Frequency Division Multiplexing (OFDM) based communication system. In at least one embodiment, the communication system is one operating according to the IEEE 802.16m, or WiMax, standard. In general, an OFDM transmitter operates to insert pilot symbols into a resource of a transmit frame according to a predetermined staggered pilot symbol pattern defining pilot symbol locations within the resource of the transmit frame. The predetermined pilot symbol pattern is defined such that pilot symbols are located at or near time boundaries of the resource, at or near frequency boundaries of the resource, or both. By doing so, when generating a channel estimate for the communication channel between the OFDM transmitter and an OFDM receiver based on the pilot symbols, extrapolations needed to estimate the channel near the boundaries of the resource are optimized, thereby improving overall channel estimation accuracy. | 01-09-2014 |
20140023046 | SOFT HANDOFF FOR OFDM - Various embodiments relate to soft handoffs in an OFDM system. Each mobile terminal measures pilot signal strengths of transmissions from adjacent base stations. If the pilot signal strength for a base station exceeds the defined threshold, that base station is added to an active set list. Each mobile terminal notifies the base stations of their active set lists. By providing the set list to the base station controller and the servicing base station, the mobile terminal identifies the sole servicing base station or triggers a soft handoff mode when multiple base stations appear on the active set list. The soft handoff mode uses a combination of scheduling and space-time coding to affect efficient and reliable handoffs. | 01-23-2014 |
20140036823 | System Access and Synchronization Methods for MIMO OFDM Communications Systems and Physical Layer Packet and Preamble Design - A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame. | 02-06-2014 |
20140050144 | Method and System using Relays with Aggregated Spectrum - International Mobile Telecommunications (IMT) Advanced technology, also known as 4th Generation (4G) targets to support up to 100 MHz BW. LTE currently supports single carrier bandwidths of up to 20 MHz. The present application describes a multi-carrier approach in which some embodiments of the invention provide a simple solution of aggregating multiple single carrier bandwidths to obtain a wider bandwidth (>20 MHz). Such an approach may extend Long Term Evolution (LTE) bandwidth to greater than that provided by a single carrier, yet maintain full backward compatibility with technologies that predate 4G technology and utilize smaller, single carrier bandwidths. More generally, embodiments of the invention can apply to other communication standards than only LTE. | 02-20-2014 |
20140064243 | Method and Systems for OFDM Using Code Division Multiplexing - In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions. | 03-06-2014 |
20140072076 | System and Method for Mapping Symbols for MIMO Transmission - Methods and devices are provided for MIMO OFDM transmitter and receivers having odd and/even numbers of transmit antennas. Various methods for pre-coding information bits before space time coding (STC) are described for enabling transmission of information bits over all antennas. Methods of decoding received signals that have been pre-coded and STC coded are also provided by embodiments of the invention. Pilot patterns for downlink and uplink transmission between a base station and one or more wireless terminals for three transmit antenna transmitters are also provided. Variable rate codes are provided that combine various fixed rate codes in a manner that results in codes whose rates are dependent on all the various fixed rate codes that are combined | 03-13-2014 |
20140079152 | Adaptive Two-Dimensional Channel Interpolation - A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency). | 03-20-2014 |
20140119471 | Adaptive Two-Dimensional Channel Interpolation - A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency). | 05-01-2014 |
20140161068 | Method and System for Providing an Uplink Structure and Minimizing Pilot Signal Overhead in a Wireless Communication Network - A method and system are provided having an uplink control structure and a pilot signal having minimal signal overhead for providing channel estimation and data demodulation in a wireless communication network. The uplink control structures enable mobile terminals to communicate with corresponding base stations to perform various functions including obtaining initial system access, submitting a bandwidth request, triggering a continuation of negotiated service, or providing a proposed allocation re-configuration header. A dedicated random access channel is provided to communicatively couple the base station and the mobile terminal so that the mobile terminal can select a random access signaling identification. A resource request is received at the base station to uplink resource information from the mobile terminal and an initial access information request is received from the mobile terminal to configure the base station connection. Pilot signals with varying density configurations are provided to include low density symbol patterns for multiple contiguous resource blocks and high density symbol patterns for single resource blocks. | 06-12-2014 |
20140211726 | Systems and Methods for SC-FDMA Diversity Transmission - The present application provides methods, devices and transmitters that mitigate increases in peak to average power ratio (PAPR) from transmission diversity in a single carrier frequency division multiple access (SC-FDMA) modulated uplink. A PAPR preserving precode matrix hopping method that utilizes cyclic shift delays is provided, as well as a sub-band based transmit diversity scheme. The present application also provides methods, devices and transmitters that relax the scheduling restrictions associated with uplink scheduling in the LTE standard. | 07-31-2014 |
20140211778 | Systems and Methods for SC-FDMA Diversity Transmission - The present application provides methods, devices and transmitters that mitigate increases in peak to average power ratio (PAPR) from transmission diversity in a single carrier frequency division multiple access (SC-FDMA) modulated uplink. A PAPR preserving precode matrix hopping method that utilizes cyclic shift delays is provided, as well as a sub-band based transmit diversity scheme. The present application also provides methods, devices and transmitters that relax the scheduling restrictions associated with uplink scheduling in the LTE standard. | 07-31-2014 |
20140219240 | Method and System for Combining OFDM and Transformed OFDM - Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM. | 08-07-2014 |
20140219387 | Method and System for Combining OFDM and Transformed OFDM - Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM. | 08-07-2014 |
20140269489 | System and Method for Unbalanced Relay-Based Wireless Communications - A method and system for wireless communication with a mobile device in which wireless communication is established with the mobile device. A base station is used to transmit directly to the mobile device in a downlink direction. A relay node is used to transmit to the base station communications received in an uplink direction from the mobile station. The relay node relays at least a portion of the uplink traffic received from the mobile station to the base station. | 09-18-2014 |
20140314183 | Scattered Pilot Pattern And Channel Estimation Method For MIMO-OFDM Systems - A method and apparatus are provided for reducing the number of pilot symbols within a MIMO-OFDM communication system, and for improving channel estimation within such a system. For each transmitting antenna in an OFDM transmitter, pilot symbols are encoded so as to be unique to the transmitting antenna. The encoded pilot symbols are then inserted into an OFDM frame to form a diamond lattice, the diamond lattices for the different transmitting antennae using the same frequencies but being offset from each other by a single symbol in the time domain. At the OFDM receiver, a channel response is estimated for a symbol central to each diamond of the diamond lattice using a two-dimensional interpolation. The estimated channel responses are smoothed in the frequency domain. The channel responses of remaining symbols are then estimated by interpolation in the frequency domain. | 10-23-2014 |
20140348271 | Methods and Systems for Orthogonal Frequency Division Multiplexing (OFDM) Multiple Zone Partitioning - Aspects of the invention include methods and devices for inserting data and pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) frames having a time domain and a frequency domain. A method involves inserting in at least one zone of a first type a two dimensional array of data and pilot symbols in time and frequency and inserting in at least one zone of a second type a two dimensional array of data and pilot symbols in time and frequency. In some implementations the zone of the first type comprises common pilot symbols that can be detected by all receivers receiving the OFDM frame. In some implementations the zone of the second type comprises dedicated pilot symbols that are only detectable by a receiver that is aware of pre-processing used to encode the dedicated pilot symbols. | 11-27-2014 |
20150016394 | Pilot Scheme for a MIMO Communication System - The present invention employs a pilot scheme for frequency division multiple access (FDM) communication systems, such as single carrier FDM communication systems. A given transmit time interval will include numerous traffic symbols and two or more short pilot symbols, which are spaced apart from one another by at least one traffic symbol and will have a Fourier transform length that is less than the Fourier transform length of any given traffic symbol. Multiple transmitters will generate pilot information and modulate the pilot information onto sub-carriers of the short pilot symbols in an orthogonal manner. Each transmitter may use different sub-carriers within the time and frequency domain, which is encompassed by the short pilot symbols within the transmit time interval. Alternatively, each transmitter may uniquely encode the pilot information using a unique code division multiplexed code and modulate the encoded pilot information onto common sub-carriers of the short pilot symbols. | 01-15-2015 |
20150045057 | Method and System for User Equipment Location Determination on a Wireless Transmission System - Neighbor cell hearability can be improved by including an additional reference signal that can be detected at a low sensitivity and a low signal-to-noise ratio, by introducing non-unity frequency reuse for the signals used for a time difference of arrival (TDOA) measurement, e.g., orthogonality of signals transmitted from the serving cell sites and the various neighbor cell sites. The new reference signal, called the TDOA-RS, is proposed to improve the hearability of neighbor cells in a cellular network that deploys 3GPP EUTRAN (LTE) system, and the TDOA-RS can be transmitted in any resource blocks (RB) for PDSCH and/or MBSFN subframe, regardless of whether the latter is on a carrier supporting both PMCH and PDSCH or not. Besides the additional TDOA-RS reference signal, an additional synchronization signal (TDOA-sync) may also be included to improve the hearability of neighbor cells. | 02-12-2015 |
20150049738 | Pilot Scheme for a MIMO Communication System - The present invention employs a pilot scheme for frequency division multiple access (FDM) communication systems, such as single carrier FDM communication systems. A given transmit time interval will include numerous traffic symbols and two or more short pilot symbols, which are spaced apart from one another by at least one traffic symbol and will have a Fourier transform length that is less than the Fourier transform length of any given traffic symbol. Multiple transmitters will generate pilot information and modulate the pilot information onto sub-carriers of the short pilot symbols in an orthogonal manner. Each transmitter may use different sub-carriers within the time and frequency domain, which is encompassed by the short pilot symbols within the transmit time interval. Alternatively, each transmitter may uniquely encode the pilot information using a unique code division multiplexed code and modulate the encoded pilot information onto common sub-carriers of the short pilot symbols. | 02-19-2015 |
20150055725 | Pilot Design for Wireless System - The description herein relates to pilot designs for an Orthogonal Frequency Division Multiplexing (OFDM) based communication system. In at least one embodiment, the communication system is one operating according to the IEEE 802.16m, or WiMax, standard. In general, an OFDM transmitter operates to insert pilot symbols into a resource of a transmit frame according to a predetermined staggered pilot symbol pattern defining pilot symbol locations within the resource of the transmit frame. The predetermined pilot symbol pattern is defined such that pilot symbols are located at or near time boundaries of the resource, at or near frequency boundaries of the resource, or both. By doing so, when generating a channel estimate for the communication channel between the OFDM transmitter and an OFDM receiver based on the pilot symbols, extrapolations needed to estimate the channel near the boundaries of the resource are optimized, thereby improving overall channel estimation accuracy. | 02-26-2015 |
20150085820 | Scattered Pilot Pattern And Channel Estimation Method For MIMO-OFDM Systems - Methods and apparatus are provided for inserting data symbols and pilot symbols in an OFDM (orthogonal frequency division multiplexing) transmission resource utilizing frequency hopping patterns for the data symbols and/or the pilot symbols. Data symbols and pilot symbols are allocated for down link (base station to mobile station) and up link (mobile station to bases station) transmission resources in a two-dimensional time-frequency pattern. For each antenna of a MIMO-OFDM (multiple input multiple output OFDM) communication system, pilot symbols are inserted in a scattered pattern in time-frequency and data symbols are inserted in an identical frequency-hopping pattern in time-frequency as that of other antennas. | 03-26-2015 |
20150085821 | Methods and Systems for OFDM using Code Division Multiplexing - In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions. | 03-26-2015 |
20150085945 | Systems and Methods for OFDM Channelization - Systems and methods for OFDM channelization are provided that allow for the coexistence of sub-band channels and diversity channels. Methods of defining diversity sub-channels and sub-band sub-channels are provided and systematic channel definition and labeling schemes are provided. | 03-26-2015 |
20150085961 | Pilot Design for Wireless System - The description herein relates to pilot designs for an Orthogonal Frequency Division Multiplexing (OFDM) based communication system. In at least one embodiment, the communication system is one operating according to the IEEE 802.16m, or WiMax, standard. In general, an OFDM transmitter operates to insert pilot symbols into a resource of a transmit frame according to a predetermined staggered pilot symbol pattern defining pilot symbol locations within the resource of the transmit frame. The predetermined pilot symbol pattern is defined such that pilot symbols are located at or near time boundaries of the resource, at or near frequency boundaries of the resource, or both. By doing so, when generating a channel estimate for the communication channel between the OFDM transmitter and an OFDM receiver based on the pilot symbols, extrapolations needed to estimate the channel near the boundaries of the resource are optimized, thereby improving overall channel estimation accuracy. | 03-26-2015 |