Patent application number | Description | Published |
20080225763 | Group MMSE-DFD with Rate (SINR) Feedback and Without Pre-Determined Decoding Order for Reception on a Cellular Downlink - In accordance with the invention, a method includes the steps of: i) initializing with channel matrix estimates and inner codes of all co-channel transmitter sources in a wireless network, modulation and coding schemes of all sources not of interest; ii) converting each channel matrix estimate into an effective channel matrix responsive to the inner code of the corresponding transmitter source; iii) selecting iteratively from a first set of transmitter sources transmitting at fixed rates, a transmitter source which maximizes a first metric; iv) computing iteratively a filter for the transmitter source which maximizes the first metric; v) selecting iteratively from a second set of transmitter sources of interest, a transmitter source which maximizes a second metric; vi) computing iteratively a rate and a filter for the transmitter source which maximizes the second metric; and vii) obtaining an ordered set of indices of all transmitter sources that will be decoded along with their corresponding filters, and feedback rates for all transmitter sources of interest. | 09-18-2008 |
20080225781 | Group MMSE-DFD with Order and Filter Computation for Reception on a Cellular Downlink - A method for decoding in a wireless downlink channel, where all dominant transmitting sources use inner codes from a particular set, including the steps of: estimating a channel matrix seen from each dominant transmitter source in response to a pilot or preamble signal transmitted by each such source; converting each estimated channel matrix into an effective channel matrix responsive to the inner code of the corresponding transmitting source; obtaining the received observations in a linear equivalent form whose output is an equivalent of the received observations and in which the effective channel matrix corresponding to each dominant transmitting source inherits the structure of its inner code; i) determining an order for processing each of the transmitting sources; ii) computing a filter for each transmitting source that will be decoded; iii) demodulating and decoding each transmitting source responsive to the determined order from step i) assuming perfect cancellation of signals of preceding or previously decoded transmitting sources; and iv) re-encoding the decoded message of each transmitting source, except the source decoded last, responsive to the modulation and coding scheme employed by the source and the corresponding effective channel matrix and subtracting it from the received observations in the equivalent linear form. | 09-18-2008 |
20080225974 | Max-Log Receiver for Multiple-Input Multiple-Output (MIMO) Systems - A method includes the steps of i) listing out all possibilities for a first symbol of a two stream signal; ii) determining a second symbol of the two stream signal for each of the first symbol listed out, iii) evaluating a metric for each of the first symbol and second symbol pair, iv) listing out all possibilities for second symbol, v) determining a first symbol for each choice of the second symbol listed out, vi) evaluating a metric for each of the second symbol and first symbol pair, vii) determining an exact maximum log likelihood ratio for all bits using the metrics, and viii) decoding codeword(s) in the two stream signal using the determined exact maximum log likelihood ratio for all bits. | 09-18-2008 |
20080225976 | METHOD FOR MULTIPLE-INPUT-MULTIPLE-OUTPUT SYSTEM DEMODULATION - A MMSE-based deterministic sequential Monte Carlo (SMC) method for MIMO demodulation exhibiting square root complexity in terms of constellation size. Further extensions to the method reduce the search space resulting in significant reduction in computational requirements while minimally impacting performance. As a hard decision algorithm, the methods achieve sphere decoder performance while imposing a much smaller computational load. | 09-18-2008 |
20080225979 | Group MMSE-DFD with Rate (SINR) Feedback and Pre-Determined Decoding Order for Reception on a Cellular Downlink - A method for decoding and rate assignment in a wireless channel, where all dominant transmitter sources use inner codes from a particular set, comprising the steps of: i) estimating channel matrices seen from all dominant transmitter sources in response to a pilot or preamble signal transmitted by each such source; ii) converting each estimated channel matrix into an effective channel matrix responsive to the inner code of the corresponding transmitter source; iii) obtaining the received observations in a linear equivalent form (linear model) whose output is an equivalent of the received observations and in which the effective channel matrix corresponding to each dominant transmitter source inherits the structure of its inner code; iv) processing the transmitter sources according to the specified (or pre-determined) order of decoding; v) for each transmitter source, assuming perfect cancellation of signals of preceding transmitter sources; vi) computing a signal-to-interference-noise-ratio SINR responsive to the effective channel matrix of the transmitter source and the covariance matrix of the noise plus signals from remaining transmitter sources; and vii) feeding back all computed SINRs to respective transmitter sources. | 09-18-2008 |
20080227397 | Group LMMSE Demodulation Using Noise and Interference Covariance Matrix for Reception on a Cellular Downlink - A method for filtering in a wireless downlink channel, where all dominant transmitting sources use inner codes from a particular set, includes the steps of estimating a channel matrix seen from a desired transmitter source in response to a pilot or preamble signal; converting the estimated channel matrix into an effective channel matrix responsive to the inner code of the desired transmitting source; estimating a covariance matrix of noise plus interference in a linear model whose output is an equivalent of the received observations and in which the effective channel matrix corresponding to each dominant transmitting source inherits the structure of its inner code; computing a signal-to-noise-interference-ratio SINR responsive to the covariance matrix and the effective channel matrix corresponding to the desired source; and feeding back the computed SINR to the transmitter source. | 09-18-2008 |
20090129328 | Wireless Communication Rate Allocation on a Gaussian Interference Channel - There is provided a method for allocating transmission rates in a wireless network, includes the steps of associating transmitters with corresponding receivers for communicating on an interference channel in the wireless network, and allocating a transmission rate to each transmitter for decoding by its corresponding receiver, the allocated transmission rate being equal to a desired rate of a fixed user rate and being no less than a minimum rate of a variable user rate. The step of allocating can include a sequential allocation that meets the minimum rate requirement of all users and assigns excess rates to variable rate users in a sequential fashion according to specified priorities. The step of allocating can include a parallel symmetric rate allocation when all variable rate users have the same priority and that meets minimum rate requirements of all users and is symmetric fair. The step of allocating can include a parallel iterative rate allocation with the sequence of rate allocations obtained for each user being non-decreasing and a rate allocation vector obtained after each iteration meets minimum rate requirements for all users and is max-min fair when all variable rate users have the same priority. | 05-21-2009 |
20090262872 | RECEIVER WITH PREFILTERING FOR DISCRETE FOURIER TRANSFORM-SPREAD-ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (DFT-S-OFDM) BASED SYSTEMS - A receiver for discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) based systems, including a prefilter for received signal codeword(s); and a log-likelihood ratio LLR module responsive to the prefilter; wherein the prefilter includes a pairing and whitening module that based on channel estimates and data rate enables the LLR module to perform either a Serial-In-Serial-Out (SISO) based log likelihood ratio processing of an output from the paring and whitening module or a two-symbol max-log soft output demodulator (MLSD) based log likelihood ratio processing of an output from the pairing and whitening module. | 10-22-2009 |
20090276679 | Hybrid ARQ Transmission Method With Channel State Information - A method for decoding of multiple wireless signals by a chase combining hybrid-automatic-repeat-request CC-HARQ receiver includes demodulating wireless signals received from respective mobile sources using an effective channel matrix and decision statistics; updating log-likelihood-ratios LLRs and decoding the received codewords using the corresponding updated LLRs; determining set of correctly decoded codewords using a cyclic redundancy check; updating the effective channel matrix and decision statistics responsive to the step of determining; and resetting the effective channel matrix and decision statistics in the event that the number of decoding errors for a codeword exceeds its maximum limit after storing the updated LLRs of all remaining erroneously decoded codewords for which the number of decoding errors is below the respective maximum limit. | 11-05-2009 |
20100157924 | MU-MIMO-OFDMA SYSTEMS AND METHODS FOR SERVICING OVERLAPPING CO-SCHEDULED USERS - Methods and systems for conveying or transmitting to any given user in an OFDMA-MU-MIMO system scheduling information of other co-scheduled users to permit the user to perform error-correction on received data and/or interference reduction on its received signals. The scheduling information can include resource block assignment, modulation constellations employed, coding rates employed, power levels utilized and precoder matrix indices used. Further, the scheduling information can be conveyed in part through dedicated reference symbol layers or pilot streams. Moreover, a base station may transmit a preliminary estimate of the total number of users the base station expects to schedule, or an upper-bound on the total number of users, to the MU-MIMO users to permit the MU-MIMO users to determine preferred precoder matrix indices and indications of channel quality indices. | 06-24-2010 |
20120057557 | Method and Systems for Conveying Scheduling Information of Overlapping Co-Scheduled Users in an OFDMA-MU-MIMO System - Methods and systems for conveying or transmitting to any given user in an OFDMA-MU-MIMO system scheduling information of other co-scheduled users to permit the user to perform error-correction on received data and/or interference reduction on its received signals. The scheduling information can include resource block assignment, modulation constellations employed, coding rates employed, power levels utilized and precoder matrix indices used. Further, the scheduling information can be conveyed in part through dedicated reference symbol layers or pilot streams. Moreover, a base station may transmit a preliminary estimate of the total number of users the base station expects to schedule, or an upper-bound on the total number of users, to the MU-MIMO users to permit the MU-MIMO users to determine preferred precoder matrix indices and indications of channel quality indices. | 03-08-2012 |
20120057558 | Method and Systems for Conveying Scheduling Information of Overlapping Co-Scheduled Users in an OFDMA-MU-MIMO System - Methods and systems for conveying or transmitting to any given user in an OFDMA-MU-MIMO system scheduling information of other co-scheduled users to permit the user to perform error-correction on received data and/or interference reduction on its received signals. The scheduling information can include resource block assignment, modulation constellations employed, coding rates employed, power levels utilized and precoder matrix indices used. Further, the scheduling information can be conveyed in part through dedicated reference symbol layers or pilot streams. Moreover, a base station may transmit a preliminary estimate of the total number of users the base station expects to schedule, or an upper-bound on the total number of users, to the MU-MIMO users to permit the MU-MIMO users to determine preferred precoder matrix indices and indications of channel quality indices. | 03-08-2012 |
20120281662 | Scheduling Information of Overlapping Co-Scheduled Users in an OFDMA-MU-MIMO System - A user equipment (UE) used in a multi-user (MU)-multiple input multiple output (MIMO) orthogonal frequency division multiple access (OFDMA) system is disclosed. The UE includes a receiving unit to receive from a base station an indication of an estimate of or an upper-bound on the total number of MU-MIMO user equipments (|S|) that are scheduled on a sub-band by the base station, wherein the sub-band includes one or more resource units, a calculation unit to calculate channel quality based on the indication of the estimate of or the upper-bound on the total number of MU-MIMO user equipments, and a transmission unit to transmit to the base station an indication of the channel quality. Other methods and apparatuses also are disclosed. | 11-08-2012 |
20130242926 | METHODS AND SYSTEMS FOR CONVEYING SCHEDULING INFORMATION OF OVERLAPPING CO-SCHEDULED USERS IN AN OFDMA-MU-MIMO SYSTEM - A method implemented in a base station for conveying scheduling information in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system is disclosed. The method includes transmitting to a first user equipment (UE) the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of at least one second UE, wherein the scheduling information includes a resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE. Other methods, systems, and apparatuses also are disclosed. | 09-19-2013 |