Patent application number | Description | Published |
20080247442 | Method, Apparatus, and System for Modulating and Demodulating Signals Compatible with Multiple Receiver Types and Designed for Improved Receiver Performance - A method, apparatus, and system for modulating and demodulating signals compatible with multiple receiver types and designed for improved receiver performance. The invention includes the use of hybrid impulse radio (H-IR) ultra-wideband (UWB) with forward error correction coding, recursive modulation and other techniques designed to enable one transmitter to transmit a waveform capable of being demodulated concurrently by a coherent receiver, a differentially coherent receiver, and/or a non-coherent receiver. | 10-09-2008 |
20080259896 | Device, Method And Protocol For Private Uwb Ranging - An apparatus, system, method and computer program product for secure ranging between at least two devices in radio communications with each other. In particular, an apparatus, system, method and computer program product for secure ranging between at least two devices communicating via ultra wideband (UWB) protocols. Either ternary-IR or time-hope-IR sequences are used for ranging and security. A first device transmits a range packet. A second device responds to the range packet after a delay time known only to the first and second devices. The delay time can be selected randomly by either to the first device or the second device and made known to the other device in an encrypted notification packet. | 10-23-2008 |
20090016372 | Signaling and Training for Antenna Selection in OFDMA Networks - A method selects antennas in an OFDMA wireless network including a base station and a mobile station. The mobile station measures a channel state of a downlink in a downlink subframe using different subsets of available antennas, and selects a subset of receive antennas for downlink reception based on the channel states between the base station and the different subsets of antennas at the mobile station. The base station measures the channel state in an uplink using an uplink subframe received in the base station from the mobile station, and selects a subset of transmit antennas for mobile station's uplink transmission based on the channel states between the base station and different subset of antennas at the mobile station. | 01-15-2009 |
20090088176 | Method for Reducing Inter-Cell Interference in Wireless OFDMA Networks - Protocols for OFDM/OFDMA/SC-FDMA based wireless networks provide adaptive inter-cell interference management without explicit spectrum or frequency planning. Base stations and mobile stations acquire information about subcarrier allocation from a handoff protocol. The mobile stations can also acquire this information using cognitive sensing. Cognitive sensing can be rewarded by the base station. Using this information, subcarriers can be allocated randomly, with blind optimization, or by joint optimization. The stations can use game theory to select among the different optimization strategies. | 04-02-2009 |
20090091400 | Method and Apparatus for Generating Dynamically Varying Time Hopping Sequences for UWB Signals - A method and apparatus modulate a polarity of a burst of pulses of the impulse radio signal using a first pseudo noise sequence generated by a shift register and a position of the burst of pulses using a second pseudo noise sequence generated by the shift register. | 04-09-2009 |
20090117911 | Cooperative Base Stations in Wireless Networks - The embodiments of the invention provide an adaptive method for base station cooperation in a wireless network. In a multi-user communications network that includes base stations, and in which each base station is associated with a cell, and in which each cell includes one or more mobile stations, each base station determines pre-coding matrices for full-cooperation, semi-cooperation and non-cooperation. Each base stations also determines a sum rate SR | 05-07-2009 |
20090124290 | Antenna Selection for SDMA Transmissions in OFDMA Networks - A method for selects antennas in a spatial division multiple access (SDMA) wireless network that includes a base station and a set of mobile stations, in which the set of mobile stations includes one or more designated mobile stations, and in which each designated mobile station has a set of multiple antennas. Channel state information (CSI) is acquired for a channel between each mobile station in the set of mobile stations and the base station, and in which the CSI for each designated mobile station is acquired for different subsets of the set of multiple antennas at each designated mobile station. For each designated mobile station, a globally optimal subset of the set of antennas is selected based on the CSI acquired from all the mobile stations. | 05-14-2009 |
20090180568 | Hybrid Automatic Repeat Requests Coding in MIMO Networks - A method transmits a block of symbols in a multiple-input multiple-output (MIMO) network including a transmitter having a set of transmit antennas and a receiver having a set of receive antennas. A block of symbols is coded with a first code to generate a first block, which is transmitted and received. If a decoding of the first block is incorrect, then block of symbols is coded with the first code and then a second code different than the first code to generate a second block. The second block is transmitted, received and combined with the first block to recover the block of symbols. | 07-16-2009 |
20090262852 | Coding for Large Antenna Arrays in MIMO Networks - A method transmits a sequence of symbols in a multiple-input multiple-output (MIMO) network including a transmitter having a set of transmit antennas and a receiver having a set of receive antennas. The sequence of symbols is represented by a vector S=[S | 10-22-2009 |
20090286471 | Method for Allocating Power to Source and Relay Stations in Two-Hop Amplify-and-Forward Relay Multi-Input-Multi-Output Networks - Disclosed is a method for static power allocation to source and relay stations in a two-hop amplify-and-forward (AF) relay multi-input-multi-output (MIMO) network including of a source station (SS), a relay station (RS), and a destination station (DS) each transmitting signals using multiple antennas. The method performs power allocation to the SS and the RS according to the path loss, or equivalently, according to a distances, between the SS and the RS and the RS and DS. The transmit power of each transmit antenna at the SS and the power amplifying gain of the RS are determined from the power allocation outputs. | 11-19-2009 |
20100097985 | Method for Randomly Accessing a Wireless Network - In a wireless network including a base station (BS) and a set of mobile stations (MS), a MS transmits a ranging request message to the BS, using random access, when the MS enters the cell. The ranging request message includes request MS specific information for identifying the MS. The MS receives a ranging response message broadcast from the BS, which includes response MS specific information, request and response specific information to determine whether the BS received the request, or whether a collision occurred. | 04-22-2010 |
20100182982 | Method for Broadcasting Alert Message in Mobile Multi-Hop Networks Using Inferred Distance Prioritization - A method and system broadcasts an alert packet in a wireless multi-hop network of nodes. An event is sensed in a source node of the network, and an alert packet is broadcast in response to sensing the event. The alert packet is received in a set of candidate nodes within a broadcast range of the source node. Each candidate node infers a distance between the candidate node and the source node based on a receive power of the received alert packet, and determines a priority for rebroadcasting the alert packet, wherein the priority is based on the distance to minimizing a probability of collisions while rebroadcasting the alert packet and extend a range of the rebroadcasting. | 07-22-2010 |
20100188966 | Feedback for Transmit Precoding in Wireless Networks - Channel state information for closed-loop transmit precoding in MIMO networks is fed back from the MSs to the BSs. The feedback is quantized using codebooks shared by the MSs and BSs to reduce overhead. The codebooks can be full-rank or rank-one. The quantized feedback is applicable to any definitions of MIMO channel covariance matrix as well as MIMO channel matrix. Since these codebooks are designed for closed-loop MIMO precoded transmissions, no additional memory is needed to store the codebooks at the BS and the MS only for the quantized feedback purposes. | 07-29-2010 |
20100195751 | Method for Estimating Channels in Two-Hop MIMO AF Networks - A method estimates interim channels in a two-hop multi-input-multi-output (MIMO) amplify-and-forward (AF) relay network including a source station (SS), a relay station (RS), and a destination station (DS). The estimate is according to the overall channel obtained at the DS or the SS. By varying an amplifying matrix of the RS over time, the method establishes a linear equation group with respect to the elements of the interim channels over the first (SS-RS) and second (RS-SS) hops, based on which low-complexity estimation of the interim channels is performed. | 08-05-2010 |
20100220682 | Method for Optimizing Performance in Multi-Cell OFDMA Networks - A method optimizes a performance of a multi-cell orthogonal frequency-division multiple access (OFDMA) network that includes a set of base stations (BSs) located in a cell, and each BS transmits data on downlink channels to a set of mobile stations (MSs) in the cell. Each BS acquires channel state information (CSI) and inter-cell interference information (ICI) for each downlink channel to each MS in the cell. Each BS selects a power level and a modulation coding scheme level (MCS) for transmitting the data to each MS on the downlink channels based on the CSI and ICI, such that a bit rate is maximized and the ICI is minimized. Then, time and frequency resource are allocated for transmitting the data on the downlink channels to the set of MSs, such that the allocated resources are minimized to optimize the performance of the network. | 09-02-2010 |
20100246375 | Carrier Allocation and Time Sharing FOR OFDMA/TDMA Networks - A method allocates bandwidth to channels in an orthogonal frequency division multiple access and time division multiple access (TDMA) network. The network includes a master device (master) communicating with a set of slave devices (slaves). The master defines a set Ψ | 09-30-2010 |
20100246703 | Unified STTC Encoder for WAVE Transceivers - A transmitter encodes an input bitstream using space-time trellis coding (STTC). The encoder includes a serial to parallel convertor to produce a first and second output bitstreams. First and second three bit shift registers are connected to produce first and second output bitstreams. A multiplier applies a code generating weight to each bit of the shift registers to encode the bitstreams. A first switch is connected between a last bit of the first shift register and a first bit of the second shift register. A second switch is connected between the second output and the first bit of the second shift register. The first set of encoded bit streams and the second set of encoded bitstreams are combined and mapped to a frequency domain. | 09-30-2010 |
20100246718 | STTC Encoder for Single Antenna WAVE Transceivers - An encoder in a transmitter uses space-time trellis coding. An input bitstream is multiplexed to produce in parallel a set of output bitstreams. A multiplier applies a code generating weight to each output bitstream, which are combined, mapped and transmitted by a single antenna. | 09-30-2010 |
20100248672 | Beamforming in Wireless Vehicular Networks - Beams are used to communicate in a wireless network including mobile and stationary receivers. The network operates according to the IEEE 802.11p in wireless access to vehicular environments (WAVE). A direction from the mobile transceiver to the stationary receiver is predicted using geographic information available to the mobile transceiver. A set of signals are received in the mobile transceiver from the stationary transceiver, wherein the signals are received by an array of antennas, and wherein the signals are received using a set of beams, and wherein each beam is approximately directed at the stationary receiver. A signal-to-noise ratio (SNR) is measured for each beam, and the beam with an optimal SNR is selected as an optimal beam for communicating data between the mobile transceiver and the stationary transceiver. | 09-30-2010 |
20100254369 | Cooperative Ultra-Reliable Wireless Communications - A network includes a master node (master) and a set of slave nodes (slaves). The network uses orthogonal frequency-division multiplexing (OFDM) and time division multiple access (TDMA) symbols on sub-carriers. During a first downlink transmission from the master to the set of slaves using downlinks and all of the sub-carriers, a broadcast polling packet including data packets for each slave and sub-carrier assignments for the slaves is broadcast. Each slave transmits simultaneously to the master using uplinks and the assigned sub-carriers, a first response packet after receiving the broadcast polling packet. The master then broadcasts using the downlinks and all of the sub-carriers, a group acknowledgement packet, wherein the broadcast polling packet, the response packet, and the group acknowledgement packet include one superframe in one communication cycle, and wherein the broadcasting on the downlinks and the transmitting on the uplinks are disjoint in time. | 10-07-2010 |
20100260276 | Zero Correlation Zone Based Preamble for Oversampled OFDM Networks in URWIN - In an oversampled orthogonal frequency-division multiplexing (OFDM) orthogonal network, the preamble used for time synchronization does not have an ideal autocorrelation function due to guard bands, which degrade the accuracy of symbol timing. Therefore, a zero-correlation-zone (ZCZ) based preamble is used for time synchronization. Across correlation function (CCF) used for time synchronization is forced to 0 within a certain region around a main lobe. The length of the ZCZ is guaranteed to be larger than a cyclic prefix length of OFDM data symbols synchronization accuracy. | 10-14-2010 |
20100272014 | Parametric Compression of Rank-1 Analog Feedback - Channel state information in a closed-loop, multiple-input, multiple-output wireless networks is fed back from each mobile station to a base station by first determining a transmit covariance matrix R, and applying a singular value decomposition (SVD) R=UΣV | 10-28-2010 |
20110044158 | Cross-Talk Cancellation in Cooperative Wireless Relay Networks - Cross-talk is canceled in a cooperative wireless relay network that includes a base station (BS), a relay station (RS), and a mobile station (MS). A coupling channel between a transmit antenna and a receive antenna colocated at the RS is estimated. Cross-talk interference determination is based on a previous transmitted signal by the transmit antenna, and the coupling channel. The cross-talk interference is subtracted from a currently received signal by the receive antenna to obtain a residual signal. The residual signal is then transmitted as a next transmitted signal by the transmit antenna. | 02-24-2011 |
20110044172 | Method and Protocol for Congestion Control in a Vehicular Network - In a vehicle ad-hoc network (VANET), a transceiver node is arranged in a vehicle. The node includes a protocol stack, which includes an application layer, a link layer; and a congestion control layer arranged between the application layer and the link layer. The congestion layer transfers short messages between the application layer and the link layer. The short messages are defined according to a standard for the VANET, and the congestion layer optimizes a network-wide rate allocation for the short messages. | 02-24-2011 |
20110129234 | Iterative Carrier Phase Compensation in Coherent Fiber Optic Receivers - A method and an optical receiver compensates for an error in a phase of an optical signal in a receiver. The signal includes blocks of symbols in a sequence. Each block is decoded based on a partially phase compensated symbols, and an average phase error for the block is estimated. Forward phase compensation and backward phase compensation is performed on the block based on the average phase error, and the decoding, estimating, performing is iterated until a termination condition is satisfied to produce a phase compensated block. | 06-02-2011 |
20110176624 | OFDM Networks with Pseudo-Random Phase Precoding - In an orthogonal frequency division multiplexing (OFDM) network, a set of pseudo random sequences (PRS) are stored at a transmitter and a receiver. Each OFDM symbol is mapped to subcarriers for a set of transmit antennas to produce a mapped symbol. The mapped symbol is encoded using a pseudo-random phase precoder (PRPP) and the PRS to produce a precoded symbol. An inverse fast Fourier transform (IFFT) is applied to the precoded symbol, and the encoded symbol is transmitted to the receiver using the set of transmit antennas. | 07-21-2011 |
20110237198 | Method and System for Super-Resolution Blind Channel Modeling - Propagation channels are reconstructed from measurements in disjoint subbands of a wideband channel of interest. By using high-resolution estimation of multipath parameters, and suitable soft combining of the results, a channel estimate and subseqeuntly channel models can be extracted that accurately interpolate between the measured subbands. | 09-29-2011 |
20120002753 | Method for Encoding Data Symbols with Implicitly Embedded Pilot Symbols in Resource Blocks for Wireless Networks - A set of data symbols is selected from a set of modulation constellation, and a sample-mean of the set of data symbols is determined. Each data symbol is first shifted by the sample-mean to obtain a shifted data symbol, and then the shifted symbol is multiplied by a first constant to obtain a scaled data symbol. A second constant is added to the scaled data symbol to obtain a mapped data symbol. The sample-mean is multiplied by a third constant to obtain a sample-mean mapped symbol. The set of mapped data symbols and the sample-mean mapped symbol are then transmitted as a resource block. | 01-05-2012 |
20120129458 | Wireless Communication Network for Transportation Safety Systems - In a network for a safety system in a transportation system, the transportation system includes a shaft and a car arranged in the shaft. A first wall node is at a first end of the shaft and a second wall node is at a second end of the shaft to communicate safety messages with the car. Each wall node includes at least one wireless transceiver connected to one or more antennas. Each car in the shaft includes at least two wireless transceiver connected to one or more antennas, wherein the first transceiver of the car uses a first frequency and the second transceiver of the car uses a second frequency to communicate each safety messages in duplicate. A wired backbone connects the set of wall nodes to a controller of the safety system of the transportation system. | 05-24-2012 |
20120147864 | Synchronous Data Transmission in Hybrid Communication Networks for Transportation Safety Systems - A hybrid communication network for a transportation safety system includes a wired network including a set of fixed nodes. Each fixed node includes a wired interface for connecting the fixed node to the wired network and at least one wireless interface. The set of fixed nodes further includes a head node at a first end of the wired network connected to a controller, a terminal node at a second end of the wired network, and a set of relay nodes arranged between the head node and the terminal node. A wireless network includes a set of mobile nodes and a set of fixed nodes connected to the wired network. Each mobile node includes at least one of the wireless interfaces, and each mobile node is arranged in a moveable car. | 06-14-2012 |
20120147879 | Method for Scheduling Data Transmission in Hybrid Communication Networks for Transportation Safety Systems - A hybrid communication network for a transportation safety system includes a fixed wired nodes and mobile wireless nodes. Because the wired nodes operate independently packets transmitted by the wired nodes to the wireless nodes need to be synchronized. A downlink travel time for downlink packets traveling from a controller to the wireless nodes is determined. Then, the controller schedules downlink data intervals (DDI) based on the downlink travel time; and transmits downlink packets to the wireless nodes during the DDI, such that a latency requirement of the transportation safety system is satisfied. | 06-14-2012 |
20120170684 | Method and System for Decoding OFDM Signals Subject to Narrowband Interference - A method estimates a wireless channel at a receiver. The signal is transmitted using narrowband orthogonal frequency division demultiplexing (OFDM) and frequency subcarriers, and the signal includes a set of data tones and a set of pilot tones. The channel and pilot tone interference are estimated based on all the pilot tones extracted from the signal and a channel model. The set of data are equalized based on the channel estimate. Data interference is detected according to the pilot interference and the equalized data tones. Subcarrier interference-to-noise ratios are determined based on the data interference. Signal strengths of the data tones are determined based on the equalized data tones, log-likelihood ratios of bits represented by the data tones are determined based on the subcarrier interference-to-noise ratios and the signal strength of the data tones. | 07-05-2012 |
20120183020 | Non-Coherent Space-Time Trellis-Coded Modulations for Network-Coded Wireless Relay Communications - This invention provides a method for jointly optimizing network coding, channel coding, and signal constellations in non-coherent wireless multiple-input multiple-output (MIMO) wireless relay networks for the case when transceivers cannot obtain any knowledge of channel state information (CSI) due to high-speed mobility of the transceivers. In the relay networks, two terminal transceivers simultaneously transmit data to an intermediate relaying transceiver, which in turn broadcasts mixed data using physical-layer network coding to both terminals. The embodiments of this invention exploit different blind space-time trellis-coded modulations (ST-TCM) for each user, whose codebook is jointly generated over a Grassmannian manifold. The method is provided by exponential mapping with affine-lattice convolution for joint optimization of channel coding, modulations, and network coding. The method is designed for fast fading channels with and without interleaving. The method significantly improves performance in non-coherent bidirectional relaying MIMO networks. | 07-19-2012 |
20120263454 | Crosstalk-Free High-Dimensional Constellations for Dual-Polarized Nonlinear Fiber-Optic Communications - A method reduces time-varying polarization crosstalk due to XPolM by transmitting multi-dimensional orthogonal constellations. Three variants of crosstalk-free constellations are provided: Grassmann constellations, unitary constellations, and rotation codes. The method uses the Grassmann constellations and the unitary constellations to deal with fiber nonlinearity by applying as a polarization-time coding. The rotation codes exploit a fiber channel characteristic to improve performance and to reduce computational complexity. The underlying orthogonality behind those constellations enables the receiver to decode it as if there is no polarization crosstalk. Moreover, the required computational complexity at the receiver is significantly reduced because neither crosstalk cancellers nor channel estimators are needed. | 10-18-2012 |