Broadcom Corporation

Chengjin Zhang

Jun Zheng

Pieter Van Rooyen

Vinko Erceg

Pieter Roux

Severine E Catreux-Erceg

Pieter Van Rooven

Jun c/o Broadcom Corporation Zheng

Certain aspects of a method and system for processing signals in a communication system may include maximizing system capacity for a communication system, based on a signal for a user within a search range and at least one other signal for one other user within the search range. The search range may be generated by sorting a plurality of signals based on a channel gain corresponding to each of the plurality of signals. The signal for the user may be selected from the search range corresponding to a channel gain that is greater than a channel gain corresponding to a remaining portion of the search range.

Method and system for a greedy user group selection with range reduction in TDD multiuser MIMO downlink transmission

Certain aspects of a method and system for processing signals in a communication system may include maximizing system capacity for a time division duplex (TDD) multiple-input multiple-output (MIMO) system, based on reducing a search range within which to find a group of signals having maximum channel gain. At least one of: a first signal for a first user and a second signal for a second user may be selected, which are both within the reduced search range, and which provides a maximum system capacity. The first signal for the first user may be selected from the reduced search range corresponding to a channel gain that is greater than a channel gain corresponding to a remaining portion of the reduced search range. The reduced search range may be generated by sorting a plurality of signals based on a channel gain corresponding to each of the plurality of signals.

Method and system for a double search user group selection scheme with range reduction in TDD multiuser MIMO downlink transmission

Various aspects of a method and a system for finding a threshold for semi-orthogonal user group selection in multiuser MIMO downlink transmission are presented. Aspects of a system for semi-orthogonal user group selection may include a processor that computes an orthogonality measurement between one of a plurality of signals and at least one of a remaining portion of the plurality of signals. The processor may compare each of the orthogonality measurements to a threshold orthogonality value based on a computed probability. The processor may select a user group, based on the threshold orthogonality value, including one of the plurality of signals and one or more signals selected from the remaining portion of the plurality of signals.

Method and system for finding a threshold for semi-orthogonal user group selection in multiuser MIMO downlink transmission

Aspects of a greedy search user group selection scheme with range reduction for FDD multiuser MIMO downlink transmission with finite-rate channel state information feedback are provided. The method may comprise receiving feedback information via a communication channel for a plurality of users in a frequency division duplex system. The system capacity may be maximized using the feedback information based on a signal from a single user within a reduced search range or based on the signal from the single user and at least one other signal from another user within a remaining portion of the search range. The feedback information may comprise quantized gain and/or direction of the channel state information of the users.

Method and system for greedy user group selection with range reduction for FDD multiuser MIMO downlink transmission with finite-rate channel state information feedback

A method for processing signals in a communication system includes selecting, from a plurality of users, a first user having a channel gain that is greater than a channel gain corresponding to a remaining portion of the plurality of users. At least a second user may be selected from a portion of the remaining portion of the plurality of users, based on a feedback channel gain of the second user. The selected second user may have a channel direction that is approximately orthogonal to a channel direction of the first user. System capacity may be determined based on the selecting of the first user and the selecting of the second user. The channel gain may be defined by a quantized channel gain. A quantized channel direction of the selected first user may be determined for the selecting of the second user.

Method and system for a simplified user group selection scheme with finite-rate channel state information feedback for FDD multiuser MIMO downlink transmission

A method and system for channel quantization for multiuser diversity are provided. A quantizer may utilize quantization levels determined based on an objective function J that corresponds to a performance metric for a finite-rate feedback multiuser downlink communication system. The quantization levels may be obtained based on the results of maximizing the objective function J by means of an optimization algorithm. The optimization algorithm may be a multivariate optimization algorithm that may be implemented utilizing an iterative approach. The quantizer may utilize the quantization levels to quantize channel state information (CSI) to achieve multiuser diversity in the finite-rate feedback multiuser system. The performance metric may be based on signal-to-noise ratio (SNR), bit error rate (BER), and/or system capacity. The quantization levels may be utilized in a multiuser system where distributed quantization is needed for optimal selection.

Channel quantization for multiuser diversity

Various aspects of a method and a system for a range reduction scheme for user selection in a multiuser MIMO downlink transmission are presented. Aspects of a system for range reduction may comprise a range reduction processor that determines a plurality of channel measurements corresponding to a plurality of signals. The range reduction processor may compute a plurality of channel capacities based on the channel measurements corresponding to a subset of the plurality of signals having channel gain that is greater than a remaining portion of the plurality of signals. Aspects of a method may comprise determining a plurality of channel measurements corresponding to a plurality of signals, and computing a plurality of channel capacities based on said channel measurements corresponding to a subset of the plurality of signals having a channel gain that is greater than a remaining portion of the plurality of signals.

Method and system for a range reduction scheme for user selection in a multiuser MIMO downlink transmission

Certain aspects of a method and system for processing signals in a communication system may include maximizing system capacity for a time division duplex (TDD) multiuser multiple-input multiple-output (MIMO) downlink system, based on a single signal for a single user within a reduced search range or the single signal for the single user and at least one other signal for one other user within a remaining portion of the reduced search range. The reduced search range may be generated by sorting a plurality of signals based on a channel gain corresponding to each of the plurality of signals. The single signal for the single user may be selected from the reduced search range corresponding to a channel gain that is greater than a channel gain corresponding to a remaining portion of the reduced search range.

A method and system for a double search algorithm of user group selection for multiuser MIMO downlink transmission are provided. The use of optimal brute-force user group selection may require high computational expense. A first search operation may be based on a first user having a channel gain greater than that of other users, while a second search operation may be based on a second user having a channel gain greater than that of the remaining users. A maximized system capacity may be determined based on the maximized system capacities determined in the first and second search loop. A receiver pair associated with the maximized system capacity may be selected as the user group. The double search algorithm may reduce the computational complexity while achieving performances that may exceed the TDMA scheme and be similar to that of systems with ideal CSI at the transmitter.

Double search algorithm of user group selection for multiuser MIMO downlink transmission

Aspects of a double search user group selection scheme with range reduction for FDD multiuser MIMO downlink transmission with finite-rate channel state information feedback are provided. The method may comprise maximizing system capacity using feedback information for a plurality of signals in a frequency division duplex system to reduce a search range within which a group of signals having maximum channel gain are located. The feedback information may comprise quantized gain for the signals. Quantized channel direction for the signals within the reduced search range may be requested and received by the transmitter. One or two signals from the reduced search range that maximizes system capacity may be selected. The receivers associated with these signals may then be selected as the user group.

Double search user group selection scheme with range reduction for FDD multiuser MIMO downlink transmission with finite-rate channel state information feedback

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Chengjin Zhang