Receiver hardware reduction for spatially independent signals and associated methods
A communications device includes an antenna array comprising antenna elements for receiving at least N spatially independent signals, and a receiver coupled to the antenna array. The receiver includes an analog receiver circuit for receiving the N spatially independent signals, and has a bandwidth of at least N times an information bandwidth of the spatially independent signals. The receiver further includes a digital receiver circuit coupled to the analog receiver circuit, and samples the N spatially independent signals at a rate of at least N times a Nyquist rate which would have been required if a single antenna element had been used to receive the signals. A processor is coupled to the digital receiver circuit for demultiplexing the sampled N spatially independent signals.
1. A communications device comprising:
an antenna array comprising a plurality of antenna elements for receiving at least N spatially independent signals;
a receiver coupled to said antenna array and comprising
an analog receiver circuit for receiving the N spatially independent signals, and having a bandwidth of at least N times an information bandwidth of the spatially independent signals, and
a digital receiver circuit coupled to said analog receiver circuit, and sampling the N spatially independent signals at a rate of at least N times a Nyquist rate which would have been required if a single antenna element had been used to receive the signals, and comprising an analog-to-digital converter for converting the N spatially independent signals to N spatially independent digital signals;
a controller coupled to said antenna array and comprising
a switching circuit coupled to said antenna array for switching between said plurality of antenna elements for sampling the N spatially independent signals by said antenna array, and
a timing circuit coupled to said switching circuit for coordinating sampling of the N spatially independent signals by said antenna array based on sample timing of the N spatially independent digital signals by said analog-to-digital converter; and
a processor coupled to said digital receiver circuit for demultiplexing the sampled N spatially independent digital signals, and coupled to said timing circuit for providing the sample timing of the N spatially independent digital signals by said analog-to-digital converter.
2. A communications device according to claim 1 wherein said digital receiver circuit comprises a single analog-to-digital converter.
3. A communications device according to claim 1 wherein said processor demodulates in parallel the N spatially independent signals after having been demultiplexed, with the N demodulated signals then being combined for signal processing.
4. A communications device according to claim 1 wherein said processor reconstructs the N independently transmitted signals.
5. A communications device according to claim 1 wherein said plurality of antenna elements comprise N uncorrelated antenna elements.
6. A communications device according to claim 1 wherein said plurality of antenna elements comprise N correlated antenna elements.
7. A communications device according to claim 6 wherein said N correlated antenna elements comprise N active antenna elements so that said antenna array forms a phased array.
8. A communications device according to claim 6 wherein said N correlated antenna elements comprise at least one active antenna element, and up to N−1 passive antenna elements so that said antenna array forms a switched beam antenna.
9. A communications device according to claim 3 wherein the signal processing is based upon at least one of a knowledge based signal extraction process and a blind signal separation process.
10. A communications device according to claim 9 wherein the blind signal separation process is based on at least one of principal component analysis (PCA), independent component analysis (ICA) and single value decomposition (SVD).
11. A communications device according to claim 9 wherein the knowledge based signal separation process is based on at least one of a zero forcing (2F) process and a minimum mean squared estimation (MMSE) process.
12. A communications device according to claim 1 wherein the N spatially independent signals correspond to a single transmitted signal.
13. A communications device according to claim 1 wherein the N spatially independent signals correspond to N independently transmitted signals from a MIMO transmitter; and wherein said processor reconstructs the N independently transmitted signals.
14. A communications device according to claim 1 further comprising:
a transmitter; and
a switch coupled between said antenna array, said transmitter and said receiver so that the communications device operates in a half-duplex mode.
15. A communications device according to claim 1 further comprising:
a transmitter; and
at least one additional antenna element dedicated to said transmitter so that the communications device operates in a full-duplex mode.
16. A method for operating a communications device comprising an antenna array comprising a plurality of antenna elements, an analog receiver circuit coupled to the antenna array, a digital receiver circuit coupled to the analog receiver circuit comprising an analog-to-digital converter, a processor coupled to the digital receiver circuit, and a controller coupled to the antenna array and comprising a switching circuit coupled to the antenna array and a timing circuit coupled to the processor, the method comprising:
receiving at least N spatially independent signals by the antenna array;
providing the N spatially independent signals to analog receiver circuit, the analog receiver circuit having a bandwidth of at least N times an information bandwidth of the spatially independent signals;
sampling in the digital receiver circuit the N spatially independent signals at a rate of at least N times a Nyquist rate which would have been required if a single antenna element had been used to receive the signals;
converting in the analog-to-digital converter the sampled N spatially independent signals to N spatially independent digital signals;
operating the switch controller for
causing the switching circuit coupled to the antenna array to switch the plurality of antenna elements for sampling the N spatially independent signals by the antenna array based on operation of the switching circuit, and
causing the timing circuit coupled to the switching circuit to sample the N spatially independent signals by the antenna array based on a sample timing of the N spatially independent digital signals by the analog-to-digital converter; and
demultiplexing the sampled N spatially independent digital signals in the processor, and providing from the processor to the timing circuit the sample timing of the N spatially independent digital signals by the analog-to-digital converter.
17. A method according to claim 16 wherein the digital receiver circuit comprises a single analog-to-digital converter.
18. A method according to claim 16 wherein the processor demodulates in parallel the N spatially independent signals after having been demultiplexed, with the N demodulated signals then being combined for signal processing.
19. A method according to claim 16 wherein the processor reconstructs the N independently transmitted signals.
20. A method according to claim 16 wherein the plurality of antenna elements comprise N uncorrelated antenna elements.
21. A method according to claim 16 wherein the plurality of antenna elements comprise N correlated antenna elements.
22. A method according to claim 21 wherein the N correlated antenna elements comprise N active antenna elements so that the antenna array forms a phased array.
23. A method according to claim 21 wherein the N correlated antenna elements comprise at least one active antenna element, and up to N−1 passive antenna elements so that the antenna array forms a switched beam antenna.
24. A method according to claim 18 wherein the signal processing is based upon at least one of a knowledge based signal extraction process and a blind signal separation process.
25. A method according to claim 16 wherein the N spatially independent signals correspond to a single transmitted signal.
26. A method according to claim 16 wherein the N spatially independent signals correspond to N independently transmitted signals from a MIMO transmitter; and wherein the processor reconstructs the N independently transmitted signals.
27. A method according to claim 16 wherein the communications device further comprises a transmitter, and a switch coupled between the antenna array, the transmitter and the receiver so that the communications device operates in a half-duplex mode.
28. A method according to claim 16 wherein the communications device further comprises a transmitter, and at least one additional antenna element dedicated to the transmitter so that the communications device operates in a full-duplex mode.