Spatio-temporal processing for communication
A space-time signal processing system with advantageously reduced complexity. The system may take advantage of multiple transmitter antenna elements and/or multiple receiver antenna elements, or multiple polarizations of a single transmitter antenna element and/or single receiver antenna element. The system is not restricted to wireless contexts and may exploit any channel having multiple inputs or multiple outputs and certain other characteristics. Multi-path effects in a transmission medium cause a multiplicative increase in capacity.
1. An apparatus comprising:
an encoder operative to:
encode information for transmitting in accordance with an encoding scheme designed to take advantage of multiple spatial subchannels; and
form a plurality of encoded spatial subchannel signals for the multiple subchannels;
a spatial processor operative to accept the encoded spatial subchannel signals and spatially combine the encoded spatial subchannel signals to form orthogonal frequency subchannel information, one or more weights for a plurality of antenna elements defining the spatial combination;
a processor operative to accept the orthogonal frequency subchannel information and form time signals from the frequency subchannel information; and
an analog RF system operative to transmit the time signals via a plurality of antenna elements.
2. An apparatus as recited in claim 1 , wherein the spatial subchannels are orthogonal.
3. An apparatus as recited in claim 1 , wherein the processor operative to form time signals comprises one or more inverse discrete Fourier transformers.
4. An apparatus as recited in claim 1 , wherein the encoder unit comprises one or more interleavers, such that the spatial processor accepts encoded and interleaved spatial subchannel signals.
5. An apparatus as recited in claim 1 , wherein the encoder unit comprises one or more mapping units to assign QAM constellation points.
6. An apparatus as recited in claim 1 , wherein the spatial processor uses weights determined in accordance with a zero forcing procedure.
7. An apparatus as recited in claim 1 , wherein the spatial processor uses weights determined in accordance with a minimum mean square error procedure.
8. An apparatus comprising:
an encoder operative to encode information for transmitting and form a plurality of encoded spatial streams comprising the encoded information;
a spatial processor operative to accept the plurality of encoded spatial streams and spatially combine the spatial streams to form orthogonal frequency subchannel information, one or more weights for a plurality of transmit antenna elements defining the spatial combination;
a processor operative to accept the orthogonal frequency subchannel information and to form a time signal for each of the transmit antenna elements; and
a plurality of analog RF systems each operative to transmit one of the time signals via a corresponding one of the plurality of transmit antenna elements.
9. An apparatus as recited in claim 8 , wherein the processor configured to form time signals comprises one or more inverse discrete Fourier transformers.
10. An apparatus as recited in claim 8 , wherein the encoder unit comprises one or more interleavers, such that the spatial processor accepts encoded and interleaved spatial streams.
11. An apparatus as recited in claim 8 , wherein the encoder unit comprises one or more mapping units to assign QAM constellation points.
12. An apparatus as recited in claim 8 , wherein the encoder unit comprises one or more interleavers and one or more mapping units to assign QAM constellation points.
13. A method of operating a transmitting apparatus, the method comprising:
encoding information for transmitting in accordance with an encoding scheme that is designed to take advantage of multiple spatial subchannels, the encoding forming a plurality of encoded spatial subchannel signals for the multiple subchannels;
spatially combining the encoded spatial subchannel signals to form orthogonal frequency subchannel information, one or more weights for a plurality of antenna elements defining the spatial combination;
forming time signals from the frequency subchannel information; and
transmitting the time signals via a plurality of antenna elements.
14. A method as recited in claim 13 , wherein the spatial subchannels are orthogonal.
15. A method as recited in claim 13 , wherein the forming the time signals comprises inverse discrete Fourier transforming.
16. A method as recited in claim 13 , wherein the encoding comprises interleaving, such that the spatial combination is of interleaved spatial subchannel signals.
17. A method as recited in claim 13 , wherein the encoding comprises mapping to assign QAM constellation points.
18. A method as recited in claim 13 , wherein the spatial combination uses weights determined in accordance with a zero forcing procedure.
19. A method as recited in claim 13 , wherein the spatial combination uses weights determined in accordance with a minimum mean square error procedure.
20. A method of operating a transmitting apparatus, the method comprising:
encoding information for transmitting to form a plurality of encoded spatial streams comprising the encoded information;
spatially combining the spatial streams to form orthogonal frequency subchannel information, one or more weights for a plurality of transmit antenna elements defining the spatial combination;
forming a time signal for each of the transmit antenna elements from the orthogonal frequency subchannel information; and
transmitting each of the time signals via a corresponding one of the plurality of transmit antenna elements.
21. A method as recited in claim 20 , wherein the forming of the time signals comprises inverse discrete Fourier transforming.
22. A method as recited in claim 20 , wherein the encoding comprises interleaving, such that the spatial combination is of encoded and interleaved spatial streams.
23. A method as recited in claim 20 , wherein the encoding comprises assigning QAM constellation points.
24. A method as recited in claim 20 , wherein the encoding comprises interleaving and further comprises assigning QAM constellation points.