Patent application number | Description | Published |
20110059705 | ROBUST LINEAR PRECODER DESIGNS FOR MULTI-CELL DOWNLINK TRANSMISSION - Methods and systems for optimizing the utilities of receiver devices in a wireless communication network are disclosed. Precoder design formulations that maximize a minimum worst-case rate or a worst-case sum rate are described for both full base station cooperation and limited base station cooperation scenarios. In addition, optimal equalizers are also selected to optimize the worst-case sum rate. | 03-10-2011 |
20110243017 | MU-MIMO-OFDMA SYSTEMS AND METHODS FOR MULTI-RANK CQI COMPUTATION AND PRECODER SELECTION - Methods and systems for determining attributes of communication channels of MU-MIMO users in an OFDMA system are disclosed. One method comprises receiving from a base station, for at least one sub-band of contiguous sub-carriers, an indication of an estimate of or an upper-bound on a total number of streams that are co-scheduled by the base station on the at least one sub-band. In addition, the method further comprises determining one or more signal quality measures for the at-least one sub-band based on the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band. Moreover, an indication of the one or more signal quality measures is transmitted to the base station. | 10-06-2011 |
20110243018 | MU-MIMO-OFDMA METHODS AND SYSTEMS FOR SIGNALING MULTI-RANK CQIs AND PRECODERS - Methods and systems for determining attributes of communication channels of MU-MIMO users in an OFDMA system are disclosed. One method includes receiving from a base station, for at least one sub-band of contiguous sub-carriers, an indication of an estimate of or an upper-bound on a total number of streams that are co-scheduled by the base station on the at least one sub-band and an indication of a fraction of a transmit power at the base station that is applied to streams that are scheduled for transmission to a particular user. The method further includes determining one or more signal quality measures for the at least one sub-band based on at least one of the fraction or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band. In addition, an indication of the one or more signal quality measures is transmitted to the base station in the method. | 10-06-2011 |
20110243019 | MU-MIMO-OFDMA MULTI-RANK CQI AND PRECODER SIGNALING SCHEMES - Methods and systems for determining attributes of communication channels of MU-MIMO users in an (OFDMA) system are disclosed. One method includes receiving from a base station, for at least one sub-band of contiguous sub-carriers, an indication of an estimate of or an upper-bound on a total number of streams that are co-scheduled by the base station on the at least one sub-band. The method further includes determining one or more signal quality measures for the at least one sub-band based on the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band in accordance with at least one of single-user scheduling rules or multi-user scheduling rules. In addition, the method includes transmitting to the base station an indication of the one or more signal quality measures and at least one tag identifying each signal quality measure as being determined in accordance with the single-user scheduling rules or the multi-user scheduling rules. | 10-06-2011 |
20110255582 | SELECTIVE JOINT DEMODULATION - Systems, methods and apparatuses for jointly demodulating data signals are disclosed. In accordance with the method, pilot signals are received from a base station and are processed. In addition, from a set of expected co-scheduled data streams, a subset of the co-scheduled data streams that are actually transmitted by the base station are determined based on the pilot signals. Further, a group of the transmitted co-scheduled data streams are selected from the determined subset. The data signals are received and jointly demodulated by employing the selected group of co-scheduled data streams and by suppressing non-selected data streams from the determined subset. | 10-20-2011 |
20110255632 | SIGNALING OF MIXTURE COMBINATION SETS - Systems and methods for conveying and determining modulations schemes employed by co-scheduled users are disclosed. In addition, methods and systems for designing signaling schemes that convey such information are also disclosed. In accordance with one method, an index is received and a table of indices in which the received index denotes a plurality of different sets of modulation schemes is referenced. Further, one or more modulation schemes of at least one co-scheduled user is determined based on the referencing. In addition, data signals are received and are processed by utilizing the one or more modulation schemes. | 10-20-2011 |
20110304504 | Adaptive Beamforming - A computer implemented method for generating transmit (TX) and receive (RX) antenna weight vectors (AWVs) for beamforming without utilizing explicit channel estimation. | 12-15-2011 |
20110305299 | WIDEBAND CODEBOOK CONSTRUCTION AND APPLICATIONS - A precoding scheme in which the downlink channel is estimated and an optimal precoding matrix to be used by the multi antenna transmitter is determined accordingly. The optimal precoding matrix is selected from a codebook of matrices that includes matrices having a structure matched to that of the eigenvectors of the spatial covariance matrix, wherein the spatial covariance matrix is modeled as a Hermitian and Toeplitz matrix parameterized by a single complex-valued scalar. | 12-15-2011 |
20120039411 | FEED-FORWARD CONTROL SIGNALING AND DECODING SCHEMES - Systems and methods for conveying wireless transmission allocation information are disclosed. In accordance with one method, an index indicating selected data stream parameters is received. In addition, an indication of a number of transmit antennas at a transmitter from which the data stream is transmitted is also received. Further, the selected parameters are determined from the index based on the number of transmit antennas at the transmitter. Moreover, data signals are received and processed with a processor in accordance with the selected data stream parameters. | 02-16-2012 |
20120069757 | Low Complexity Link Adaptatation for LTE/LTE-A Uplink with a Turbo Receiver - An inventive method for link adaptation for an LTE/LTE-A uplink with a turbo SIC receiver includes the steps of determining a precoding matrix index PMI and rank index RI selection for an LTE/LTE-A uplink when precoding of the uplink is enabled, responsive to channel state information of a subcarrier in the uplink; determining a decoding order for codewords in the uplink i) when the precoding of the uplink is not enabled and ii) if needed when the precoding of the uplink is enabled; performing modulation and coding scheme MCS assignment for the uplink based on a hard decision successive interference cancellation SIC rule (without intra-CW cancellation) or a partial hard decision successive interference cancellation SIC rule (with intra-CW cancellation), responsive to the determined PMI and RI selection; and influencing data transmission in the uplink responsive to the MCS assignment for detection by a turbo SIC receiver. | 03-22-2012 |
20120069928 | ROBUST PRECODER AND RECEIVER FILTER DESIGN FOR GAUSSIAN INTERFERENCE CHANNEL - A system and method for providing at least one transmit precoder includes transforming at least one of a weighted sum-rate and max-min rate objective into two or more sub-problems by introducing at least one slack variable. The two or more sub-problems are iterated on a computer readable storage medium to provide at least one transmit precoder for each transmitter. | 03-22-2012 |
20120082259 | Precoding Selection for Retransmission in Uplink MIMO Hybrid ARQ - A method includes obtaining a precoder for retransmission of one codeword responsive to a known precoding matrix of a certain rank and modulation and coding scheme assignments used in an original transmission, and a desired retransmission rank', forming an approximate channel covariance matrix; stimating an a minimum mean square error receiver signal-to-noise-interference-ratio for each layer to be retransmitted responsive to the prior forming; and finding a precoding matrix from a preceding codebook that maximizes a sum-rate for enabling precoding selections for retransmissions in uplink multiple-input multiple-output MIMO hybrid automatic repeat request HARQ. | 04-05-2012 |
20120114030 | Power Scaling for Retransmissions in Uplink MIMO Hybrid ARQ - A method includes obtaining a precoder for retransmission of one codeword responsive to known precoding matrix P of rank r and modulation and coding scheme MCS assignments used in an original transmission, and a desired retransmission rank r′; and scaling power in the retransmission responsive to at least two of 1) information parameters Index of UL precoder in previous transmission, 2) rank r of uplink UL precoder in previous transmission, 3) MCS assignments in previous retransmission (MCS | 05-10-2012 |
20120163332 | COORDINATED LINEAR BEAMFORMING IN DOWNLINK MULTI-CELL WIRELESS NETWORKS - System and methods are disclosed for optimizing wireless communication for a plurality of mobile wireless devices. The system uses beamforming vectors or precoders having a structure optimal with respect to the weighted sum rate in a multi-cell orthogonal frequency division multiple access (OFDMA) downlink. A plurality of base stations communicate with the mobile devices and all base stations perform a distributed non-convex optimization exploiting the determined structure. | 06-28-2012 |
20120170530 | METHOD FOR LTE DOWNLINK SCHEDULING WITH MIMO - A method for LTE or WiMAX scheduling includes collecting, by a basestation BS, channel feedback from multiple mobiles with downlink traffic. The channel feedback enables the BS to determine an achievable rate or block error probability if transmitting to a mobile with a given modulation and coding scheme MCS and multiple-input multiple-output MIMO mode. The method includes determining, by the BS, which of the mobiles is scheduled on each resource block RB and what the MCS and MIMO mode is selected for each scheduled mobile, and allocating bits on the set of the RBs assigned to each scheduled mobile. | 07-05-2012 |
20120170531 | RESOURCE ALLOCATION IN 4G MIMO CELLULAR UPLINKS - Methods and systems for allocating resources in a cellular uplink include iteratively allocating uplink resource blocks (RBs) to a plurality of user devices in a multiple-input multiple-output network. Allocation is performed subject to constraints and incremental utility maximization according to an approximation that has a worst-case guarantee. | 07-05-2012 |
20120170676 | Robust Linear Precoder Designs for Multi-Cell Downlink Transmission - Methods and systems for optimizing the utilities of receiver devices in a wireless communication network are disclosed. Precoder design formulations that maximize a minimum worst-case rate or a worst-case sum rate are described for both full base station, cooperation and limited base station cooperation scenarios. In addition, optimal equalizers are also selected to optimize the worst-case sum rate. | 07-05-2012 |
20120170677 | COORDINATED LINEAR BEAMFORMING IN DOWNLINK MULTI-CELL WIRELESS NETWORKS - System and methods are disclosed for optimizing wireless communication for a plurality of mobile wireless devices. The system uses beamforming vectors or precoders having a structure optimal with respect to the weighted sum rate in a multi-cell orthogonal frequency division multiple access (OFDMA) downlink. A plurality of base stations communicate with the mobile devices and all base stations perform a distributed non-convex optimization exploiting the determined structure. | 07-05-2012 |
20120250804 | Efficient Square-Root Free 2 Symbol Max-Log Receiver - The present invention employs a look up table based implementation for the metric computations which eliminate redundancy and substantially reduce the number of multiplications. Moreover, inventive method exploits the fact that the un-normalized constellation symbols are complex integers so that the product of a real-number and an un-normalized constellation symbol can be implemented by only additions. The inventive method also enables a greater efficiency for whitening colored noise prior to demodulation, one of which involves no square-root operation. The invention results in less complexity, faster operation, lower power consumption, without sacrificing performance | 10-04-2012 |
20120257664 | Method for Improving Multiuser MIMO Downlink Transmissions - A method for improving multiple-input multiple-output MIMO downlink transmissions includes obtaining a channel state information CSI report including preferred matrix index PMI for precoding, channel quality index CQI and rank index RI at a base station from user terminals through a channel feedback; applying selectively a signal-to-interference-plus-noise-ratio SINR offset to a SINR of said CSI report; applying selectively a rate matching responsive to SINR offset or the CSI report; and controlling or adjusting the SINR offset. | 10-11-2012 |
20120263467 | Polmux-OFDM-DD Transmitter and Receiver for Reduced Complexity and Overhead in Optical Access/Metro Transmission - An optical communication system includes a polarization multiplexed orthogonal frequency-division multiplexing POLMUX-OFDM transmitter for generating a POLMUX-OFDM double sideband signal, an optical processing path for processing the double sideband signal from the transmitter; an analog-to-digital convert ADC-OFDM receiver coupled to the optical processing path for receiving the double sideband signal processed by the optical path; and a block-diagonal multiple-input multiple-output MIMO equalizer responsive to the receiver for enabling correct operation for a completely random incoming signal polarization state without adaptive polarization control at said receiver, which enables complexity. | 10-18-2012 |
20120275313 | Enhancement of Download Multi-User Multiple-Input Multiple-Output Wireless Communications - A method implemented in a user equipment configured to be used in a multi-user (MU) multiple-input multiple-output (MIMO) wireless communications system is disclosed. In an aspect, the user equipment transmits to a base station a first channel state information (CSI) report determined according to a single-user (SU) MIMO rule and a second CSI report based on a residual error. | 11-01-2012 |
20120275314 | Enhancement of Download Multi-User Multiple-Input Multiple-Output Wireless Communications - A method implemented in a user equipment configured to be used in a multi-user (MU) multiple-input multiple-output (MIMO) wireless communications system is disclosed. In an aspect, the user equipment transmits to a base station a first channel state information (CSI) report determined according to a single-user (SU) MIMO rule and a second CSI report determined according to an MU-MIMO rule. | 11-01-2012 |
20120294381 | Multi-User Multiple Input Multiple Output Wireless Communications - A method implemented in a user equipment used in a multi-user multiple input multiple output (MU-MIMO) wireless communications system is disclosed. The method includes receiving from a base station an indication of a first modulation type for the user equipment, receiving a first data signal for the user equipment, receiving a second data signal for a co-scheduled user equipment, where a second modulation type for the co-scheduled user equipment is unknown to the user equipment, and deciding the second modulation type. Other methods, systems, and apparatuses also are disclosed. | 11-22-2012 |
20130034176 | ROBUST LINEAR PRECODER DESIGNS FOR MULTI-CELL DOWNLINK TRANSMISSION - Methods and systems for optimizing the utilities of receiver devices in a wireless communication network are disclosed. Precoder design formulations that maximize a minimum worst-case rate or a worst-case sum rate are described for both full base station cooperation and limited base station cooperation scenarios. In addition, optimal equalizers are also selected to optimize the worst-case sum rate. | 02-07-2013 |
20130072210 | LTE and LTE-Advanced UL Power Control - A method for LTE and LTE-A uplink power control includes open loop power control where user equipment UE measures downlink pathloss which is sent to an eNodeB that determines uplink UL transmit power based on the downlink pathloss. | 03-21-2013 |
20130101063 | DFT-BASED CHANNEL ESTIMATION SYSTEMS AND METHODS - DFT-based channel estimation methods and systems are disclosed. One system includes an inverse discrete Fourier transform module, a noise power estimator, a noise filter and a discrete Fourier transform module. The inverse discrete Fourier transform module is configured to determine time domain estimates by applying an inverse discrete Fourier transform to initial channel estimates computed from pilot signals. Additionally, the noise power estimator is configured to estimate noise power by determining and utilizing time domain samples that are within a vicinity of sinc nulls of the time domain estimates. The noise filter is configured to filter noise from the time domain estimates based on the estimated noise power to obtain noise filtered time domain estimates. Further, the discrete Fourier transform module is configured to perform a discrete Fourier transform on the noise filtered time domain estimates to obtain frequency domain channel estimates for channels on which pilot signals are transmitted. | 04-25-2013 |
20130170422 | Precoder Design for Physical Layer Multicasting - A method for a transmit precoder for multicast communication over a downlink in a wireless network, including: initializing a transmit precoder, a channel estimate for each user in the wireless network; updating for each user a receive filter and a slack matrix; updating the transmit precoder by solving a second order cone routine solvable in closed form; determining if a predetermined convergence is met; and outputting the updated transmit precoder responsive to the convergence criteria. | 07-04-2013 |
20130229992 | Coordinated Multiple Point Transmission and Reception - A method implemented in a mobile communications network supporting coordinated multiple point transmission and reception (CoMP) is disclosed. The method includes transmitting, to a user equipment (UE), data in a physical downlink shared channel (PDSCH), and transmitting a reference signal to the UE, wherein a union of resource elements (REs) allocated for reference signals transmitted from a subset of a plurality of transmission points (TPs) in a CoMP set are excluded from resource mapping for transmitting the data to the UE. Other methods, systems, and apparatuses also are disclosed. | 09-05-2013 |
20130250868 | User Pairing and Resource Allocation for Downlink Multiuser Multi-Input-Multi-Output In Long Term Evolution Advanced Systems - A method for user pairing and resource allocation, includes performing a multiuser multi-input-multi-output (MU-MIMO) user pairing process to maximize an objective metric without common rank restriction; performing a rank balancing process to determine a uniform transmission user rank along all allocated resource blocks for each user; and with the uniform transmission user rank fixed for all the users, determining optimal user pairing and allocation for each of the resource blocks for each user. | 09-26-2013 |
20130286971 | SIGNALING OF MIXTURE COMBINATION SETS - A method implemented in a user terminal used in a wireless communications system is disclosed. The method comprises receiving an index, referencing a table of indices in which the received index denotes at least a total number of co-scheduled streams and one or more modulation schemes, determining at least one modulation scheme of at least one co-scheduled user based on the referencing, and receiving data signals and processing the data signals by utilizing the at least one modulation scheme, wherein each index of a plurality of the indices in the table denotes a total number of co-scheduled streams and denotes one or more stream indices for a user terminal to which the index is directed. Other methods, systems, and apparatuses also are disclosed. | 10-31-2013 |
20130329677 | FEED-FORWARD CONTROL SIGNALING AND DECODING SCHEMES - A method implemented in a base station used in a wireless communications system is disclosed. The method comprises transmitting an index indicating data stream parameters, and transmitting an indication of the number of transmit antennas at the base station, wherein the data stream parameters for 8 transmit antennas are indicated by the index according to a first table, and wherein the data stream parameters for 4 transmit antennas are indicated by the index according to a second table. Other methods, apparatuses, and systems also are disclosed. | 12-12-2013 |
20140087783 | Uplink Power Control - A method for uplink power control implemented in a wireless communications system including one or more user equipment, a serving base station, and at least one neighboring base station is disclosed. The method comprises measuring, at each user equipment, pathloss, sending, from each user equipment to the serving base station, the pathloss, and determining, at the serving base station, uplink transmit power based on the pathloss. Other methods, systems, and apparatuses also are disclosed. | 03-27-2014 |
20140133325 | Feedback and Scheduling for Coordinated Multi-Point (CoMP) Joint Transmission (JT) in Orthogonal Frequency Division Multiple Access (OFDMA) - A method implemented in a user equipment (UE) used in an orthogonal frequency division multiple access (OFDMA) wireless communications system supporting coordinated multi-point (CoMP) joint transmission (JT) is disclosed. The method includes measuring reference signal received power (RSRP), transmitting, to a network, first feedback on the RSRP, receiving, from the network, a CoMP measurement set, conducting pre-scheduling CoMP UE fallback according to the CoMP measurement set, computing channel quality and direction information according to a UE category, and transmitting, to the network, second feedback on the channel quality and direction information. Other methods, apparatuses, and systems also are disclosed. | 05-15-2014 |
20140140429 | COORDINATED MULTI-POINT TRANSMISSION AND RECEPTION SCHEMES FOR CELLULAR DOWNLINK - There is provided a method for generating transmit precoders for a communication system having a plurality of transmitters and a plurality of receivers forming a plurality of transmitter-receiver pairs. Each of the transmitters and receivers has a respective plurality of antennas. The method includes initializing the transmit precoders. The method further includes updating a plurality of receiver filters and a plurality of slack variables using closed form expressions. The method also includes updating the transmit precoders responsive to an output of said prior updating step. The method additionally includes iteratively repeating the updating steps until convergence is reached to obtain a final set of transmit precoders. The transmit precoders are updated to perform precoding for multiple stream data transmission for each of the plurality of transmitter-receiver pairs on each of a plurality of slots under a per-antenna power constraint imposed on each of the plurality of antennas. | 05-22-2014 |
20140198750 | Multi-User (MU) Multiple-Input and Multiple-Output (MIMO) Enhancement - A method implemented in a base station used in a mobile communications system is disclosed. The method includes configuring for a user equipment (UE) a channel state information (CSI) process for multi-user (MU) multiple-input and multiple-output (MIMO), the CSI process for MU-MIMO being associated with a channel part and an interference part, and according to the interference part, configuring the UE to measure or estimate inter-cell interference (ICI) and to compute or estimate intra-cell interference. Other apparatuses, systems, and methods also are disclosed. | 07-17-2014 |
20140198751 | Channel Feedback for Vertical and Full-Dimensional Beamforming - A method implemented in a base station used in a wireless communications system where different antenna arrays are employed for transmissions to different co-scheduled users in a cell is disclosed. The method includes configuring multiple channel state information (CSI) processes for a user equipment (UE), and configuring, for the UE, a plurality of non-zero power (NZP) CSI reference signal (RS) resources, each of which is associated with an antenna array. Other apparatuses, systems, and methods also are disclosed. | 07-17-2014 |
20140204865 | Exploiting Hybrid-Channel Information For Downlink Multi-User Scheduling - A method for determining an optimal network utilization maximization in a communication system with wireless links in which current and coarse channel state information CSI is available from all users, along with a limited amount of fine CSI by way of a frame based entails a scheduling and feedback under which a virtual queue is associated with each user with virtual rates being determined at start of each frame and policy of each frame being determined by solving a decision process. | 07-24-2014 |
20140219379 | Precoding Selection for Retransmission in Uplink MIMO Hybrid ARQ - A method implemented in a user terminal is disclosed. The method comprises obtaining known precoding matrix P of rank r and modulation and coding scheme assignments used in an original transmission, and a desired retransmission rank r′, forming an approximate channel covariance matrix, estimating a minimum mean square error receiver SINR for each layer to be retransmitted responsive to said forming, and finding a retransmission precoding matrix from a preceding codebook that maximizes a sum-rate for enabling precoding selections for retransmissions in uplink multiple-input multiple-output MIMO hybrid automatic repeat request HARQ. Other methods, apparatuses, and systems also are disclosed. | 08-07-2014 |
20140233414 | MU-MIMO-OFDMA METHODS AND SYSTEMS FOR SIGNALING MULTI-RANK CQIs AND PRECODERS - A method for determining attributes of communication channels of multi-user (MU)-multiple input multiple output (MIMO) users in an orthogonal frequency division multiplexing based multiple access (OFDMA) system is disclosed. The method comprises receiving from a base station, for at least one sub-band of contiguous sub-carriers, an indication of an estimate of or an upper-bound on a total number of streams that are co-scheduled by the base station on the at least one sub-band or an indication of a fraction of a transmit power at the base station that is applied to streams that are scheduled for transmission to a particular user, determining one or more signal quality measures for the at least one sub-band based on at least one of the fraction or the estimate of or the upper-bound on the total number of streams that are scheduled by the base station on the at least one sub-band, and transmitting to the base station an indication of the one or more signal quality measures. Other methods, apparatuses, and systems also are disclosed. | 08-21-2014 |
20140241449 | Codebook Construction - A method implemented in a base station used in a wireless communications system is disclosed. The method comprises having a codebook including a plurality of precoding matrices, precoding data with one of the plurality of precoding matrices, and transmitting, to a user equipment, the precoded data, wherein each precoding matrix W satisfies W=W | 08-28-2014 |
20140241450 | Codebook Construction - A method implemented in a base station used in a wireless communications system is disclosed. The method comprises having 1-layer, 2-layer, 3-layer, and 4-layer codebooks for 4 transmit antenna (4TX) transmission, each codebook including a plurality of precoding matrices, precoding data with one of the plurality of precoding matrices, and transmitting, to a user equipment, the precoded data, wherein each of the 1-layer and 2-layer codebooks comprises a first codebook and a second codebook, and wherein each precoding matrix in the first codebook comprises a first index and a second index. Other apparatuses, systems, and methods also are disclosed. | 08-28-2014 |
20140341064 | Enhancement of Download Multi-User Multiple-Input Multiple-Output Wireless Communications - A method implemented in a user equipment configured to be used in a multi-user (MU) multiple-input multiple-output (MIMO) wireless communications system is disclosed. The method includes transmitting to a base station a first channel state information (CSI) report determined according to a single-user (SU) MIMO rule, and transmitting to the base station a second CSI report determined according to an MU-MIMO rule. Other methods, apparatuses, and systems also are disclosed. | 11-20-2014 |
20140362783 | Channel State Information (CSI) Feedback and Subsampling - A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI), and a second PMI, the RI and the first PMI being jointly encoded, wherein 5 bits are used for transmission of the jointly encoded RI and first PMI, and wherein first 8 values of values expressed by the 5 bits are used for RI=1, second 8 values of the values expressed by the 5 bits are used for RI=2, a third value of the values expressed by the 5 bits is used for RI=3, a fourth value of the values expressed by the 5 bits is used for RI=4, and remaining 14 values of the values expressed by the 5 bits are reserved. Other methods, apparatuses, and systems also are disclosed. | 12-11-2014 |
20140362784 | Channel State Information (CSI) Feedback and Subsampling - A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI), and a second PMI (codebook index i | 12-11-2014 |
20140362940 | Channel State Information (CSI) Feedback and Subsampling - A method implemented in a base station used in a wireless communications system is disclosed. The method comprises receiving, from a user equipment, rank indication (RI), a first precoding matrix indicator (PMI) (codebook index i | 12-11-2014 |
20150063254 | LOW-COMPLEXITY PRECODER DESIGN FOR LARGE-SCALE MIMO COMMUNICATION SYSTEMS - A method and system are provided. The method includes providing transmit precoders for a multiple-input and multiple-output communication system having a plurality of transmit antennas. The plurality of transmit antennas are for forming, using precoding, a plurality of channels such that each of the plurality of channels are configurable to serve a respective one of a plurality of users. The providing step includes imposing a respective average transmit antenna power constraint on each of the plurality of transmit antennas. The providing step further includes determining a diagonal precoder responsive to applying column scaling to a downlink channel matrix having a plurality of rows and a plurality of columns. The providing step additionally includes generating, from the diagonal precoder, a weighted precoder in accordance with the respective average antenna power constraint by optimizing a weighted sum-rate obtained upon transmitting respective signals over the plurality of channels. | 03-05-2015 |