Patent application number | Description | Published |
20080219361 | Adaptive Pilot Symbol Allocation Method and Apparatus - According to one embodiment, a wireless communication device estimates channel response based on a reduced-density common pilot signal comprising a plurality of regularly spaced common pilot symbols when the reduced-density common pilot signal is sufficient for estimating the channel response with a desired accuracy. The wireless communication device estimates the channel response based on the reduced-density common pilot signal and one or more additional pilot symbols adaptively allocated to the wireless communication device when the reduced-density common pilot signal is insufficient for estimating the channel response with the desired accuracy. | 09-11-2008 |
20090060063 | Method and Apparatus for Robust Control Signaling Distribution in OFDM Systems - Orthogonal Frequency Division Multiplex (OFDM) systems distribute some number of pilot subcarriers within the larger set of subcarriers comprising an OFDM signal. In that context, according to teachings presented herein, control signaling is sent on subcarriers selected for their proximity to pilot subcarriers. Correspondingly, an OFDM receiver is configured to receive an OFDM signal having a control signaling subcarrier positioned proximate in a frequency-time plane to a pilot subcarrier, and generate a scalar-valued channel estimate for demodulating symbols from the control signaling subcarrier based on observations limited to the proximate pilot subcarrier. Channel estimation with respect to the control signaling subcarriers thus is robust, yet simplified. The method may be applied to all control signaling, or selectively applied to higher-priority control signaling, such as paging. | 03-05-2009 |
20090103558 | Hybrid Contention-Based and Schedule-Based Access to a Communication Link - One or more embodiments taught herein provide a hybrid access arrangement using a contention-based channel and a scheduled channel on a communication link. As a point of significant efficiency, given users transmit autonomously on the contention-based channel, without need for scheduling overhead. However, if a contention overload occurs on the contention-based channel, the involved users are identified from unique signature sequences included in their user transmissions. The identified users are temporarily managed as scheduled users on the scheduled channel, which supplements the contention-based channel and therefore may use limited communication link resources in comparison to the contention-based channel. Users not involved in the contention overload generally continue operating on the contention-based channel. | 04-23-2009 |
20090233559 | Method and Arrangement for Reducing Feedback Data in a Mimo Communication System - The present invention relates to a method and arrangement for reducing feedback data in a communication system, said communication system comprising a number of transmitter antennas, n | 09-17-2009 |
20090285173 | PILOT DESIGN USING COSTAS ARRAYS - A multi-pilot frame handler ( | 11-19-2009 |
20100111231 | OFDM CHANNEL ESTIMATION METHOD AND APPARATUS - Smaller patterns of regularly-spaced pilot symbols are discerned from a larger pattern of irregularly-spaced pilot symbols transmitted in the time-frequency domain. Accordingly, the irregularly-spaced pilot symbols can be partitioned into at least two different groups of regularly-spaced pilot symbols in the time-frequency domain. Each group of regularly-spaced pilot symbols is individually processed with lower complexity and the results combined to generate an accurate time-frequency channel response estimate. According to an embodiment, a set of irregularly-spaced pilot symbols is transmitted over a time-frequency window. Channel response is estimated based on the pilot symbols by grouping the pilot symbols into subsets of regularly-spaced pilot symbols. An intermediate quantity is generated for each subset of regularly-spaced pilot symbols as a function of the pilot symbols included in the subset. The channel response is estimated over the time-frequency window as a function of the intermediate quantities. | 05-06-2010 |
20100167717 | COORDINATED MULTIPOINT WIRELESS COMMUNICATION - Multipoint wireless communications are coordinated in cells with radiation that is emanated from antennas in an inward direction. In an example embodiment, an apparatus includes a first antenna, a second antenna, a third antenna and a controller. The first antenna emanates radiation from a first location in an inwardly direction for a cell. The second antenna emanates radiation from a second location in an inwardly direction for the cell. The third antenna emanates radiation from a third location in an inwardly direction for the cell. The controller coordinates the emanation of the radiation via the first, second, and third antennas so as to reduce intra-cell interference for remote terminals located within the cell. The coordination may be effected in accordance with one or more coordinated multi-point (transmission/reception) (CoMP) techniques. Different numbers of sub-cells and antennas per cell and different CoMP cell organizations may be implemented. | 07-01-2010 |
20100238787 | DETECTION OF TIME-FREQUENCY HOPPING PATTERNS - The present invention relates to a method for detecting a pilot pattern, comprising a pilot signal s | 09-23-2010 |
20100261482 | INTER-CELL INTERFERENCE MITIGATION - A method and controller for reducing inter-cell interference within a Coordinated Multi-Point (CoMP) cellular network architecture. Multiple CoMP cells in the network architecture are grouped into a number of mutually exclusive subsets. The CoMP cells in each subset are sufficiently separated from each other geographically so that no inter-cell interference occurs among them, and thus they can be scheduled independently. Each subset then takes turn scheduling in a certain order. As each subset schedules its transmissions, it avoids causing interference to subsets that have already scheduled, and then passes sufficient information to the remaining subsets so that the same interference avoidance measures can be taken. The scheduling and passing of the information is preferably performed before the data transmission phase, which occurs once every Transmission Time Interval (TTI). | 10-14-2010 |
20100261493 | INTER-CELL INTERFERENCE MITIGATION - A method and Coordinated Multi-Point (CoMP) cell controller for reducing interference in a wireless communication network in which a first CoMP cell neighbors a second CoMP cell. The CoMP cell controller in the first CoMP cell gathers scheduling information from border sub-cells in the neighboring second CoMP cell in which transmissions to and from UEs cause inter-CoMP cell interference in at least one sub-cell in the first CoMP cell. The CoMP cell controller augments intra-CoMP cell scheduling information in the first CoMP cell with the scheduling information from the border sub-cells to create augmented scheduling information. The CoMP cell controller then utilizes the augmented scheduling information to schedule transmissions to and from UEs within the at least one sub-cell in the first CoMP cell to reduce the inter-CoMP cell interference. | 10-14-2010 |
20100290426 | REFERENCE SYMBOL DISTRIBUTION METHOD AND APPARATUS - At least some reference symbols dedicated to a particular communication device are transmitted in resource blocks allocated to other devices. This way, reference symbol assignments are not unduly restricted by other constraints placed on the boundary elements of a resource block. According to an embodiment, data and reference signals are transmitted by transmitting a resource block allocated to a first communication device. The resource block includes a plurality of resource elements, each resource element corresponding to a modulation symbol. At least one reference symbol associated with the resource block and dedicated to the first communication device is transmitted in a resource block allocated to a second communication device. On the receive side, the communication device can perform channel estimation based on reference symbols dedicated to the device that are transmitted in resource blocks allocated to the device and in resource block(s) allocated to other communication device(s). | 11-18-2010 |
20100291936 | EXTENDED COORDINATED MULTIPOINT CELLS TO MITIGATE INTER-COMP-CELL DOWNLINK INTERFERENCE - Inter-CoMP cell interference is reduced by “extending” at least one CoMP cell to include UEs served by a neighboring CoMP cell in the extended CoMP cell's transmission calculations, so as to minimize interference to the UEs served by other CoMP cells. Each UE in a border sub-cell identifies neighboring CoMP cells from which it receives interference in excess of a threshold value, and includes the interfering CoMP cells in a close-neighbor set. The close-neighbor set is transmitted to the UE's serving CoMP cell controller. When downlink transmissions are scheduled to the target UE, the controller notifies the neighboring CoMP cells in the close-neighbor set, identifying the target UE. Those CoMP cells then use information about the channel conditions from their transmit antennas to the target UE receive antennas to compute transmissions to UEs they serve, with the constraint that interference to the target UE is below a predetermined level. | 11-18-2010 |
20100322357 | METHOD AND APPARATUS FOR ENHANCED CHANNEL ESTIMATION IN WIRELESS COMMUNICATION SYSTEMS - A method and apparatus for channel estimation based on extracting channel information, including noise spectral density, from a received signal, and advantageously exploiting that information for improved channel estimation accuracy. One embodiment is directed to a method of generating channel estimates in a wireless communication receiver, for processing a received communication signal. The method includes generating first channel estimates from a set of pilot observations obtained from the received communication signal, using a first channel estimation process that is not dependent on knowledge of channel statistics. The method further includes estimating channel statistics and a noise variance from the first channel estimates, and generating second channel estimates from the set of pilot observations, the estimated channel statistics, and the estimated noise variance, using a second channel estimation process that is dependent on knowledge of the channel statistics. | 12-23-2010 |
20100323712 | NETWORK-WIDE INTER-CELL INTERFERENCE MINIMIZATION VIA COORDINATED MULTIPOINT CELL SCHEDULING COORDINATION - Network-wide inter-cell interference is reduced by aggregating cells (herein, sub-cells) into Coordinated MultiPoint (CoMP) cells, each having a controller. The CoMP cells are divided into sets, similar to a frequency reuse plan. Scheduling information regarding transmissions scheduled to and from UEs in one set of CoMP cells is transmitted to controllers in sets of neighboring CoMP cells, in advance of the transmissions. Controllers in the receiving sets of CoMP cells schedule transmission to minimize both inter-sub-cell interference and interference with the set of CoMP cells that transmitted the scheduling information, and assuming no interference from other CoMP cells. They then transmit scheduling information to subsequent set(s) of CoMP cells. The order of scheduling information transmission between sets of CoMP cells may be rotated for fairness. The scheduling information may range from bare threshold data indicating at least one transmission, to detailed information such as estimated path gains to each UE. | 12-23-2010 |
20120033754 | OFDM CHANNEL ESTIMATION METHOD AND APPARATUS - Smaller patterns of regularly-spaced pilot symbols are discerned from a larger pattern of irregularly-spaced pilot symbols transmitted in the time-frequency domain. Accordingly, the irregularly-spaced pilot symbols can be partitioned into at least two different groups of regularly-spaced pilot symbols in the time-frequency domain. Each group of regularly-spaced pilot symbols is individually processed with lower complexity and the results combined to generate an accurate time-frequency channel response estimate. According to an embodiment, a set of irregularly-spaced pilot symbols is transmitted over a time-frequency window. Channel response is estimated based on the pilot symbols by grouping the pilot symbols into subsets of regularly-spaced pilot symbols. An intermediate quantity is generated for each subset of regularly-spaced pilot symbols as a function of the pilot symbols included in the subset. The channel response is estimated over the time-frequency window as a function of the intermediate quantities. | 02-09-2012 |