Method and apparatus for allocating downlink resources in a multiple-input multiple-output (MIMO) communication system

Claim 3

The method of claim 1 , further comprising: forming a plurality of sub-hypotheses for each hypothesis, wherein each sub-hypothesis corresponds to specific assignments of the transmit antennas to the one or more terminals in the hypothesis, and wherein the performance of each sub-hypothesis is evaluated and one of the evaluated sub-hypotheses is selected based on the performance.

Claim 4

The method of claim 1 , wherein the assigning includes identifying a transmit antenna and terminal pair with a best performance among all unassigned transmit antennas, assigning the transmit antenna in the pair to the terminal in the pair, and removing the assigned transmit antenna and terminal from consideration.

Claim 5

The method of claim 1 , wherein each hypothesis is evaluated based in part on channel state information (CSI) for each terminal in the hypothesis, wherein the CSI is indicative of channel characteristics between the transmit antennas and the terminal.

Claim 6

The method of claim 4 , wherein the CSI for each terminal comprise signal-to-noise-plus-interference ratio (SNR) estimates derived at the terminal based on signals transmitted from the transmit antennas.

Claim 7

The method of claim 5 , wherein each set of one or more terminals to be evaluated is associated with a respective matrix of SNRs achieved by the one or more terminals in the set.

Claim 8

The method of claim 5 , wherein one or more sets of antenna beams are evaluated by each terminal to be considered for scheduling to provide one or more vectors of SNRs, one vector for each set of antenna beams.

Claim 9

The method of claim 4 , further comprising: determining a coding and modulation scheme for each transmit antenna based on the CSI associated with the transmit antenna.

Claim 10

The method of claim 1 , wherein the one or more terminals in each set are selected from among a pool of terminals.

Claim 11

The method of claim 9 , wherein the pool of terminals includes one or more SIMO terminals each designated to receive a single data stream.

Claim 12

The method of claim 10 , wherein the selected hypothesis includes a plurality of SIMO terminals.

Claim 13

The method of claim 8 , wherein the pool of terminals includes one or more MIMO terminals each designated to receive multiple data streams from multiple transmit antennas.

Claim 14

The method of claim 12 , wherein the selected hypothesis includes a single MIMO terminal.

Claim 15

The method of claim 12 , wherein each scheduled MIMO terminal performs successive cancellation receiver processing to recover data transmitted to the MIMO terminal.

Claim 16

The method of claim 1 , wherein each set includes terminals having similar link margins.

Claim 17

The method of claim 1 , wherein the evaluating includes computing a performance metric for each hypothesis.

Claim 18

The method of claim 16 , wherein the performance metric is a function of throughput achievable by each terminal in the hypothesis.

Claim 19

The method of claim 16 , wherein the hypothesis having the best performance metric is selected for scheduling.

Claim 20

The method of claim 1 , further comprising: prioritizing terminals to be considered for scheduling.

Claim 21

The method of claim 19 , wherein the plurality of transmit antennas are assigned to the one or more terminals in each set based on the priority of the terminals in the set.

Claim 22

The method of claim 20 , wherein a highest priority terminal in the set is assigned a transmit antenna associated with a highest throughput, and a lowest priority terminal in the set is assigned a transmit antenna associated with a lowest throughput.

Claim 23

The method of claim 19 , further comprising: limiting terminals to be considered for scheduling to a group of N highest priority terminals, where N is one or greater.

Claim 24

The method of claim 19 , further comprising: maintaining one or more metrics for each terminal to be considered for scheduling, and wherein the priority of each terminal is determined based in part on the one or more metrics maintained for the terminal.

Claim 25

The method of claim 23 , wherein one metric maintained for each terminal relates to an average throughput rate achieved by the terminal.

Claim 26

The method of claim 19 , wherein the priority of each terminal is further determined based on one or more factors maintained for the terminal and associated with quality of service (QoS).

Claim 27

The method of claim 1 , wherein the one or more terminals in the selected hypothesis are scheduled for data transmission over a channel that includes plurality of spatial subchannels.

Claim 28

The method of claim 1 , wherein the one or more terminals in the selected hypothesis are scheduled for data transmission over a channel that includes plurality of frequency subchannels.

Claim 31

The method of claim 28 , wherein the evaluating includes determining a throughput for the one or more terminals in the sub-hypothesis based on the specific antenna assignments, and wherein the sub-hypothesis with highest throughput is selected.

Claim 32

The method of claim 28 , wherein one set of terminals is formed, and wherein the terminals in the set is selected based on priority of terminals desiring data transmission.

Claim 33

A multiple-input multiple-output (MIMO) communication system, comprising: a base station comprising a plurality of transmit antennas, a scheduler configured to receive channel state information (OSI) indicative of channel estimates for a plurality of terminals in the communication system, select a set of one or more terminals for data transmission on a downlink based at least in part on the received OSI, and assign the plurality of transmit antennas to the one or more selected terminals, a transmit data processor configured receive and process data for the one or more selected terminals based on the CSI to provide a plurality of data streams, and a plurality of modulators configured to process the plurality of data streams to provide a plurality of modulated signals suitable for transmission from the plurality of transmit antennas; and one or more terminals, each terminal comprising: a plurality of receive antennas, each receive antenna configured to receive the plurality of modulated signals transmitted from the base station, a plurality of front-end units, each front-end unit configured to process a signal from an associated received antenna to provide a respective received signal, a receive processor configured to process a plurality of received signals from the plurality of front-end units to provide one or more decoded data streams, and to further derive OSI for the plurality of modulated signals, and a transmit data processor configured to process the CSI for transmission back to the base station.

Claim 34

A multiple-input multiple-output (MIMO) communication system, comprising: a base station comprising a plurality of transmit antennas, a scheduler configured to receive channel state information (OSI) indicative of channel estimates for a plurality of terminals in the communication system, select a set of one or more terminals for data transmission on a downlink based at least in part on the received OSI, and assign the plurality of transmit antennas to the one or more selected terminals, a transmit data processor configured receive and process data for the one or more selected terminals based on the CSI to provide a plurality of data streams, and a plurality of modulators configured to process the plurality of data streams to provide a plurality of modulated signals suitable for transmission from the plurality of transmit antennas; and one or more terminals, each terminal comprising: a plurality of receive antennas, each receive antenna configured to receive the plurality of modulated signals transmitted from the base station, a plurality of front-end units, each front-end unit configured to process a signal from an associated received antenna to provide a respective received signal, a receive processor configured to process a plurality of received signals from the plurality of front-end units to provide one or more decoded data streams, and to further derive OSI for the plurality of modulated signals, and a transmit data processor configured to process the CSI for transmission back to the base station.

Claim 35

A base station in a multiple-input multiple-output (MIMO) communication system, comprising: a transmit data processor configured to receive and process data to provide a plurality of data streams for transmission to one or more terminals scheduled for data transmission, wherein the data is processed based on channel state information (OSI) indicative of channel estimates for the one or more scheduled terminals; a plurality of modulators configured to process the plurality of data streams to provide a plurality of modulated signals; a plurality of transmit antennas configured to receive and transmit the plurality of modulated signals to the one or more scheduled terminals; and a scheduler configured to receive OSI for a plurality of terminals in the communication system, select a set of one or more terminals for data transmission based at least in part on the received CSI, and assign the plurality of transmit antennas to the one or more selected terminals.

Claim 36

A base station in a multiple-input multiple-output (MIMO) communication system, comprising: a transmit data processor configured to receive and process data to provide a plurality of data streams for transmission to one or more terminals scheduled for data transmission, wherein the data is processed based on channel state information (OSI) indicative of channel estimates for the one or more scheduled terminals; a plurality of modulators configured to process the plurality of data streams to provide a plurality of modulated signals; a plurality of transmit antennas configured to receive and transmit the plurality of modulated signals to the one or more scheduled terminals; and a scheduler configured to receive OSI for a plurality of terminals in the communication system, select a set of one or more terminals for data transmission based at least in part on the received CSI, and assign the plurality of transmit antennas to the one or more selected terminals.

Claim 37

The base station of claim 32 , wherein the data stream for each transmit antenna is processed based on a coding and modulation scheme selected for the transmit antenna based on the CSI associated with the transmit antenna.

Claim 38

The base station of claim 32 , further comprising: a plurality of demodulators configured to process a plurality of signals received via the plurality of transmit antennas to provide a plurality of received signals, and a receive data processor configured to further process the plurality of received signals to derive CSI for the plurality of terminals in the communication system.

Claim 39

A terminal in a multiple-input multiple-output (MIMO) communication system, comprising: a plurality of receive antennas, each receive antenna configured to receive a plurality of modulated signals transmitted from a base station; a plurality of front-end units, each front-end unit configured to process a signal from an associated received antenna to provide a respective received signal; a receive processor configured to process a plurality of received signals from the plurality of front-end units to provide one or more decoded data streams, and to further derive channel state information (CSI) for each decoded data stream; and a transmit data processor configured to process the CSI for transmission back to the base station, and wherein the terminal is one of one or more terminals included in a set scheduled to receive data transmission from the base station in a particular time interval, and wherein the set of one or more terminals scheduled to receive data transmission is selected from among one or more sets of terminals based at least in part on OSI received from the one or more terminals in each set.

Claim 40

A terminal in a multiple-input multiple-output (MIMO) communication system, comprising: a plurality of receive antennas, each receive antenna configured to receive a plurality of modulated signals transmitted from a base station; a plurality of front-end units, each front-end unit configured to process a signal from an associated received antenna to provide a respective received signal; a receive processor configured to process a plurality of received signals from the plurality of front-end units to provide one or more decoded data streams, and to further derive channel state information (CSI) for each decoded data stream; and a transmit data processor configured to process the CSI for transmission back to the base station, and wherein the terminal is one of one or more terminals included in a set scheduled to receive data transmission from the base station in a particular time interval, and wherein the set of one or more terminals scheduled to receive data transmission is selected from among one or more sets of terminals based at least in part on OSI received from the one or more terminals in each set.

Claim 41

The terminal of claim 35 , wherein the terminal is scheduled to receive data transmission from one or more transmit antennas at the base station assigned to the terminal.

Claim 44

The apparatus of claim 37 , further comprising: means for forming a plurality of sub-hypotheses for each hypothesis, wherein each sub-hypothesis corresponds to specific assignments of the transmit antennas to the one or more terminals in the hypothesis, and wherein the performance of each sub-hypothesis is evaluated and one of the evaluated sub-hypotheses is selected based on the performance.

Claim 45

The apparatus of claim 37 , wherein means for assigning includes: means for identifying a transmit antenna and terminal pair with a best performance among all unassigned transmit antennas; means for assigning the transmit antenna in the pair to the terminal in the pair; and means for removing the assigned transmit antenna and terminal from consideration.

Claim 46

The apparatus of claim 37 , wherein each hypothesis is evaluated based in part on channel state information (OSI) for each terminal in the hypothesis, wherein the OSI is indicative of channel characteristics between the transmit antennas and the terminal.

Claim 47

The apparatus of claim 40 , wherein the OSI for each terminal comprise signal-to-noise-plus-interference ratio (SNR) estimates derived at the terminal based on signals transmitted from the transmit antennas.

Claim 48

The apparatus of claim 40 , further comprising: means for determining a coding and modulation scheme for each transmit antenna based on the OSI associated with the transmit antenna.

Claim 49

The apparatus of claim 42 , wherein means for evaluating includes: means for computing a performance metric for each hypothesis.

Claim 50

The apparatus of claim 43 , wherein the performance metric is a function of throughput achievable by each terminal in the hypothesis.

Claim 51

The apparatus of claim 37 , further comprising: means for prioritizing terminals to be considered for scheduling.

Claim 52

The apparatus of claim 45 , wherein the plurality of transmit antennas are assigned to the one or more terminals in each set based on the priority of the terminals in the set.

Claim 53

The apparatus of claim 45 , further comprising: means for maintaining one or more metrics for each terminal to be considered for scheduling, wherein the priority of each terminal is determined based in part on the one or more metrics maintained for the terminal.

Claim 56

The apparatus of claim 48 , wherein means for evaluating includes: means for determining a throughput for the one or more terminals in the sub-hypothesis based on the specific antenna assignments, and wherein the sub-hypothesis with highest throughput is selected.