Method and apparatus for implementing space time processing with unequal modulation and coding schemes
A method and apparatus for implementing spatial processing with unequal modulation and coding schemes (MCSs) or stream-dependent MCSs are disclosed. Input data may be parsed into a plurality of data streams, and spatial processing is performed on the data streams to generate a plurality of spatial streams. An MCS for each data stream is selected independently. The spatial streams are transmitted via multiple transmit antennas. At least one of the techniques of space time block coding (STBC), space frequency block coding (SFBC), quasi-orthogonal Alamouti coding, time reversed space time block coding, linear spatial processing and cyclic delay diversity (CDD) may be performed on the data/spatial streams. An antennal mapping matrix may then be applied to the spatial streams. The spatial streams are transmitted via multiple transmit antennas. The MCS for each data stream may be determined based on a signal-to-noise ratio of each spatial stream associated with the data stream.
1. A method for transmitting multiple data streams, the method comprising:
generating a first spatial stream and a second spatial stream;
performing space time block coding (STBC) processing on the first spatial stream to generate at least two STBC processed space-time streams;
performing cyclic delay diversity (CDD) processing on each of the STBC processed space-time streams;
performing CDD processing on the second spatial stream to generate space-time stream, wherein the space-time stream is not STBC processed; and
transmitting each of the STBC processed space-time streams and the space-time stream via a plurality of transmit antennas.
2. The method of claim 1 , further comprising:
performing spatial mapping to map the STBC processed space-time streams and the space-time stream to the plurality of transmit antennas.
3. The method of claim 2 , wherein an antenna mapping matrix is multiplied to the STBC processed space-time streams.
4. The method of claim 3 , wherein the antenna mapping matrix is an identity matrix.
5. The method of claim 3 , wherein the antenna mapping matrix is for spatial spreading.
6. The method of claim 3 , wherein the antenna mapping matrix is a channel-specific steering matrix.
7. The method of claim 3 , wherein the antenna mapping matrix includes a set of channel eigenvectors.
8. The method of claim 1 , wherein a modulation and coding scheme (MCS) for each of the first spatial stream and the second spatial stream is determined independently based on a signal-to-noise ratio of each spatial stream.
9. The method of claim 1 , wherein each of the STBC processed space-time streams and the space-time stream are transmitted simultaneously via the plurality of transmit antennas.
10. A device comprising:
a plurality of transmit antennas; and
a processor configured to:
generate a first spatial stream and a second spatial stream,
perform space time block coding (STBC) processing on the first spatial stream to generate at least two STBC processed space-time streams,
perform cyclic delay diversity (CDD) processing on each of the STBC processed space-time streams,
perform CDD processing on the second spatial stream to generate a space-time stream, wherein the space-time stream is not STBC processed, and
transmit each of the STBC processed space-time streams and the space-time stream via the plurality of transmit antennas.
11. The device of claim 10 , wherein the processor is further configured to perform spatial mapping to map the STBC processed space-time streams and the space-time stream to the plurality of transmit antennas.
12. The device of claim 11 , wherein an antenna mapping matrix is multiplied to the STBC processed space-time streams.
13. The device of claim 12 , wherein the antenna mapping matrix is an identity matrix.
14. The device of claim 12 , wherein the antenna mapping matrix is for spatial spreading.
15. The device of claim 12 , wherein the antenna mapping matrix is a channel-specific steering matrix.
16. The device of claim 12 , wherein the antenna mapping matrix includes a set of channel eigenvectors.
17. The device of claim 10 , wherein a modulation and coding scheme (MCS) for each of the first spatial stream and the second spatial stream is determined independently based on a signal-to-noise ratio of each spatial stream.
18. The method of claim 1 , wherein the CDD processing further comprises:
cyclically rotating a vector of symbols on at least one of the STBC processed space-time streams or the space-time stream.
19. The device of claim 10 , wherein the processor is further configured to cyclically rotate a vector of symbols of the STBC processed space-time streams or the space-time stream.
20. The device of claim 10 , wherein each of the STBC processed space-time streams and the space-time stream are transmitted simultaneously via the plurality of transmit antennas.