System and method for channel-adaptive antenna selection
View Patent ↗Systems and methods that provide channel-adaptive antenna selection in multi-antenna-element communication systems are provided. In one embodiment, a method that selects a subset of receive antennas of a receiver to receive a transmitted RF signal may include, for example, one or more of the following: establishing possible subsets of the receive antennas; determining sets of channel parameter statistics corresponding to the possible subsets of the receive antennas; computing output bit error rates of the receiver, each output bit error rate being computed based on at least one set of channel parameter statistics; selecting a particular possible subset of the receive antennas based upon a criterion predicated on the computed output bit error rates; and connecting one or more RF chains of the receiver to the receive antennas of the selected particular possible subset.
1. A method for selecting a subset of receive antennas of a receiver to receive a transmitted radio frequency (RF) signal, comprising:
establishing possible subsets of the receive antennas;
determining sets of channel parameter statistics corresponding to the possible subsets of the receive antennas;
computing output bit error rates of the receiver, each output bit error rate being computed based on at least one set of channel parameter statistics;
selecting a particular possible subset of the receive antennas based upon a criterion predicated on the computed output bit error rates; and
connecting one or more RF chains of the receiver to the receive antennas of the selected particular possible subset.
2. The method according to claim 1 , comprising: selecting transmission modes, each transmission mode being selected based on at least one set of channel parameter statistics; and predicating the criterion on at least the selected transmission modes.
3. The method according to claim 2 , wherein the selection of transmission modes comprises selecting a modulation level and a coding rate.
4. The method according to claim 2 , wherein each selected transmission mode comprises a modulation level and a coding rate.
5. The method according to claim 1 , wherein each set of channel parameter statistics comprises one or more of the following: an output signal-to-noise ratio, an output signal-to-interference-and-noise ratio, a log-likelihood ratio, and a Euclidian distance in a signal constellation of the receiver.
6. The method according to claim 1 , wherein each set of channel parameter statistics comprises one or more of the following: a first-order statistic, a second-order statistic, and a higher-order statistic.
7. The method according to claim 1 , wherein each set of channel parameter statistics is computed over a time domain.
8. The method according to claim 1 , wherein the criterion is based on a minimization of the output bit error rates.
9. The method according to claim 1 , wherein the criterion is based on one or more of the following: a maximization of a data rate within a first stage of the receiver and a minimization of the output bit error rates in a second stage of the receiver.
10. The method according to claim 1 , wherein at least one of the output bit error rates is approximated by a closed-form expression.
11. The method according to claim 1 , wherein each output bit error rate is approximated by a closed-form expression.
12. The method according to claim 1 , wherein at least one of the output bit error rates is approximated by a closed-form expression, and wherein the closed-form expression is based on one of the following: a) y=−tan h(x), b) y=−[(1−e −2√{square root over (x)} )+(1−e −1.8x )], c) y=−[(1−e −1.3√{square root over (x)} )+(1−e −x )], d) y=−(1−e −0.2x ), and e) y=−(1−e −0.35√{square root over (x)} ).
13. The method according to claim 1 , wherein at least one of the output bit error rates is approximated by a closed-form expression, and wherein the closed-form expression is dependent upon a coding or a modulation of the transmitted RF signal.
14. The method according to claim 1 , wherein at least one of the output bit error rates is approximated by a closed-form expression, and wherein the closed-form expression is a function of an output signal-to-noise ratio or an output signal-to-noise-and-interference ratio of the receiver.
15. The method according to claim 1 , wherein the receive antennas are greater in number than the number of RF chains, and wherein the number of receive antennas in each possible subset is equal to the number of the RF chains.
16. The method according to claim 1 , wherein the transmitted RF signal comprises one or more of the following: a code division multiple access signal, a single carrier signal, an orthogonal frequency division multiplexed signal, and an ultra-wideband (UWB) signal.
17. The method according to claim 1 , wherein the transmitted RF signal comprises one or more of the following: a spread spectrum signal, multiple carrier signals, space-time diversity signals, and spatially-multiplexed signals.
18. The method according to claim 1 , wherein the receiver is part of a multiple-input-multiple-output (MIMO) communication device.
19. The method according to claim 1 , wherein the receiver comprises M receive antennas and N RF chains, wherein M and N are integers, wherein N is less than M, and wherein the receiver performs the computing, the selecting, and the connecting.
20. The method according to claim 19 , wherein the receiver computes a respective output bit error rate for each possible N antenna subset of the M antennas,
wherein the receiver selects a particular N antenna subset based on a criterion predicated on the computed output bit error rates, and
wherein, in response to the selection of the particular N antenna subset based on the criterion, the receiver couples the N RF chains to the N antennas of the particular N antenna subset.