Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A communications method implemented in a transmission point (TP) used in a coordinated multipoint transmission and reception (CoMP) system is disclosed. The communications method includes transmitting, to a user equipment (UE), an indication of a channel state information (CSI) process in a CSI pattern comprising a set of CSI processes, wherein the UE is configured with the CSI process for at least one of the other CSI processes in the CSI pattern, and wherein a reported rank indication (RI) for the CSI process is the same as an RI for said at least one of the other CSI processes. Other methods, apparatuses, and systems are also disclosed.

Abstract: A communications method implemented in a transmission point (TP) used in a coordinated multipoint transmission and reception (CoMP) system is disclosed. The communications method comprises transmitting, to a user equipment (UE), attributers for up to four indicators indicating at least physical downlink shared channel (PDSCH) resource element (RE) mapping, and transmitting, to the UE, one of the four indicators, each of which is conveyed in 2 bits, wherein the four indicators comprises ‘00’, ‘01’, ‘10’, and ‘11’ corresponding to a first set, a second set, a third set, and a fourth set of parameters, respectively. Other methods, apparatuses, and systems are also disclosed.

Abstract: 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.

Abstract: A wireless communications system is disclosed. The system comprises a baseband processing unit (BBU) pool including one or more baseband processing units (BBUs), and a plurality of remote radio heads (RRHs) connected to the BBU pool through a front-haul network, wherein the wireless communications system has a plurality of sectors, each of which includes one or more small cells, each of which is deployed by one of the plurality of RRHs, wherein a BBUs is mapped to two or more RRHs in a sector in a one-to-many configuration, and a BBU is mapped to a single RRH in a sector in a one-to-one configuration, and wherein a combination of the one-to-one configuration and the one-to-many configuration is applied to each sector. Other systems, apparatuses, and methods also are disclosed.

Abstract: A wireless system includes a transmitter with a baseband processor responsive to groups of transmitter antenna arrays for communicating over directional beams; and a receiver with a baseband processor responsive to groups of receiver antenna rays for communicating with the transmitter over the directional beams, the receiver including both a rank adaptation providing a transmit mode feedback to the transmitter and a blind beamforming providing a transmit beamformer index feedback to the transmitter and receiver groups of antenna arrays.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.