Unified MIMO transmission and reception
A “unified” MIMO system that supports multiple operating modes for efficient data transmission is described. Each operating mode is associated with different spatial processing at a transmitting entity. For example, four operating modes may be defined for (1) full-CSI or partial-CSI transmission and (2) with or without steering transmit diversity (STD). An appropriate operating mode may be selected for use based on various factors (e.g., availability of a good channel estimate). With steering transmit diversity, data is spatially spread and transmitted on multiple spatial channels, and a single rate may then be used for all spatial channels used for data transmission. A receiving entity may utilize a minimum mean square error (MMSE) technique for all operating modes. The receiving entity may derive a spatial filter matrix and perform receiver spatial processing in the same manner for all operating modes, albeit with different effective channel response matrices.
1. A method of processing data in a multiple-input multiple-output (MIMO) communication system, comprising:
selecting an operating mode from among a plurality of operating modes supported by the system, each operating mode being associated with different spatial processing by a transmitting entity, wherein at least one of the plurality of operating modes utilizes steering transmit diversity and at least one of the plurality of operating modes supports data transmission on one or more spatial channels without steering transmit diversity, wherein the steering transmit diversity is achieved by performing spatial processing with a plurality of steering matrices at the transmitting entity, and wherein each element of the plurality of steering matrices belongs in a set comprising +1, −1, +j, and −j, where j is a square root of −1; and
performing spatial processing for data transmission or data reception in accordance with the selected operating mode.
2. The method of claim 1 , wherein the selected operating mode supports data transmission on one or more spatial channels without steering transmit diversity.
3. The method of claim 2 , wherein the performing spatial processing for data transmission comprises
multiplexing data symbols into a plurality of streams of data symbols for transmission from a plurality of transmit antennas.
4. The method of claim 2 , wherein the performing spatial processing for data reception comprises
performing spatial processing on symbols received from a plurality of receive antennas with at least one spatial filter matrix derived based on at least one channel response matrix for a MIMO channel used for data transmission.
5. The method of claim 1 , wherein the selected operating mode supports data transmission on one or more spatial channels with steering transmit diversity.
6. The method of claim 5 , wherein the performing spatial processing for data transmission comprises
multiplying data symbols with a plurality of steering matrices to obtain a plurality of streams of transmit symbols for transmission from a plurality of transmit antennas.
7. The method of claim 5 , wherein the performing spatial processing for data reception comprises
performing spatial processing on symbols received from a plurality of receive antennas with a plurality of spatial filter matrices derived based on at least one channel response matrix for a MIMO channel used for data transmission and a plurality of steering matrices used by the transmitting entity for steering transmit diversity.
8. The method of claim 1 , wherein the selected operating mode supports data transmission on one or more orthogonal spatial channels.
9. The method of claim 8 , wherein the performing spatial processing for data transmission comprises
multiplying data symbols with at least one eigenmode matrix to obtain a plurality of streams of transmit symbols for transmission from a plurality of transmit antennas, each eigenmode matrix being used to transmit the data symbols on the one or more orthogonal spatial channels.
10. The method of claim 8 , wherein the performing spatial processing for data reception comprises
performing spatial processing on symbols received from a plurality of receive antennas with at least one spatial filter matrix derived based on a channel estimate for a MIMO channel used for data transmission.
11. The method of claim 1 , wherein the selected operating mode supports data transmission on one or more orthogonal spatial channels with steering transmit diversity.
12. The method of claim 11 , wherein the performing spatial processing for data transmission comprises
multiplying data symbols with a plurality of steering matrices to obtain spread symbols, and
multiplying the spread symbols with at least one eigenmode matrix to obtain a plurality of streams of transmit symbols for transmission from a plurality of transmit antennas.
13. The method of claim 11 , wherein the performing spatial processing for data reception comprises
performing spatial processing on symbols received from a plurality of receive antennas with a plurality of spatial filter matrices derived based on a channel estimate for a MIMO channel used for data transmission and a plurality of steering matrices used by the transmitting entity for steering transmit diversity.
14. The method of claim 1 , wherein a pilot is transmitted on one or more spatial channels used for data transmission.
15. The method of claim 1 , wherein a pilot is transmitted with steering transmit diversity on one or more spatial channels used for data transmission.
16. The method of claim 1 , wherein the MIMO system utilizes orthogonal frequency division multiplexing (OFDM), and wherein a plurality of steering matrices are used for a plurality of frequency subbands for steering transmit diversity.
17. An apparatus in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
a controller operative to select an operating mode from among a plurality of operating modes supported by the system, each operating mode being associated with different spatial processing by a transmitting entity, wherein at least one of the plurality of operating modes utilizes steering transmit diversity and at least one of the plurality of operating modes supports data transmission on one or more spatial channels without steering transmit diversity, wherein the steering transmit diversity is achieved by performing spatial processing with a plurality of steering matrices at the transmitting entity, and wherein each element of the plurality of steering matrices belongs in a set comprising +1, −1, +j, and −j, where j is a square root of −1; and
a spatial processor operative to perform spatial processing for data transmission or data reception in accordance with the selected operating mode.
18. The apparatus of claim 17 , wherein the selected operating mode supports data transmission on one or more spatial channels without steering transmit diversity.
19. The apparatus of claim 17 , wherein the selected operating mode supports data transmission on one or more spatial channels with steering transmit diversity.
20. The apparatus of claim 17 , wherein the selected operating mode supports data transmission on one or more orthogonal spatial channels.
21. The apparatus of claim 17 , wherein the selected operating mode supports data transmission on one or more orthogonal spatial channels with steering transmit diversity.
22. An apparatus in a wireless multiple-input multiple-output (MIMO) communication system, comprising:
means for selecting an operating mode from among a plurality of operating modes supported by the system, each operating mode being associated with different spatial processing by a transmitting entity, wherein at least one of the plurality of operating modes utilizes steering transmit diversity and at least one of the plurality of operating modes supports data transmission on one or more spatial channels without steering transmit diversity, wherein the steering transmit diversity is achieved by performing spatial processing with a plurality of steering matrices at the transmitting entity, and wherein each element of the plurality of steering matrices belongs in a set comprising +1, −1, +j, and −j, where j is a square root of −1; and
means for performing spatial processing for data transmission or data reception in accordance with the selected operating mode.
23. The apparatus of claim 22 , wherein the selected operating mode supports data transmission on one or more spatial channels without steering transmit diversity.
24. The apparatus of claim 22 , wherein the selected operating mode supports data transmission on one or more spatial channels with steering transmit diversity.
25. The apparatus of claim 22 , wherein the selected operating mode supports data transmission on one or more orthogonal spatial channels.
26. The apparatus of claim 22 , wherein the selected operating mode supports data transmission on one or more orthogonal spatial channels with steering transmit diversity.
27. A non-transitory computer-readable medium having one or more software modules stored thereon, the one or more software modules being executable by one or more processors and the one or more software modules comprising:
code for selecting an operating mode from among a plurality of operating modes supported by the system, each operating mode being associated with different spatial processing by a transmitting entity, wherein at least one of the plurality of operating modes utilizes steering transmit diversity and at least one of the plurality of operating modes supports data transmission on one or more spatial channels without steering transmit diversity, wherein the steering transmit diversity is achieved by performing spatial processing with a plurality of steering matrices at the transmitting entity, and wherein each element of the plurality of steering matrices belongs in a set comprising +1, −1, +j, and −j, where j is a square root of −1; and
code for performing spatial processing for data transmission or data reception in accordance with the selected operating mode.
28. The computer-program apparatus of claim 27 , wherein the selected operating mode supports data transmission on one or more spatial channels without steering transmit diversity.
29. The computer-program apparatus of claim 27 , wherein the selected operating mode supports data transmission on one or more spatial channels with steering transmit diversity.
30. The computer-program apparatus of claim 27 , wherein the selected operating mode supports data transmission on one or more orthogonal spatial channels.
31. The computer-program apparatus of claim 27 , wherein the selected operating mode supports data transmission on one or more orthogonal spatial channels with steering transmit diversity.