Channel information feedback method and wireless communication device using the same
First Claim
1. A channel information feedback method, adapted to a multi-antenna system, comprising:
- estimating, at a wireless communication device, parameters of a MIMO channel as a MIMO channel matrix based on signals received from a transmitter, and vectorizing the MIMO channel matrix into a first vector as an estimated MIMO channel representation;
applying compressive sensing technique, at the wireless communication device, to take random measurements of the estimated MIMO channel representation by a pre-configured random matrix, so as to obtain compressive sensing measurements; and
feeding back the compressive sensing measurements to the transmitter from the wireless communication device,wherein the step of applying the compressive sensing technique to take random measurements of the estimated MIMO channel representation by the pre-configured random matrix comprises;
reducing, at the wireless communication device, dimension of the first vector from N to M by multiplying the first vector with a M×
N pre-configured random matrix to obtain a second vector, wherein N>
M and M and N are positive integers;
wherein the step of feeding back the compressive sensing measurements to the transmitter comprises;
transmitting, at the wireless communication device, the second vector to the transmitter;
wherein before the step of reducing dimension of the first vector from N to M by multiplying the first vector with a M×
N pre-configured random matrix to obtain the second vector, the channel information feedback method further comprises;
determining, at the wireless communication device, error rate based on the signals received from the transmitter;
comparing, at the wireless communication device, the error rate with pre-determined multi-level thresholds; and
determining, at the wireless communication device, a compression ratio corresponding to the value of M, in accordance to the comparison result of the error rate and the pre-determined multi-level thresholds.
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Abstract
A channel information feedback method for multi-antenna system, and a wireless communication device using the same method are provided. The proposed method could reduce feedback overhead for multiple-input multiple-output (MIMO) wireless channel information, and is based on compressive sensing technique. Prior to sending back channel information, a receiver estimates the channel and multiplies the vectorized channel with a random matrix to generate compressed feedback content. Upon receiving the compressed feedback content at a transmitter, the channel information could be restored with signal recovery algorithms of compressive sensing technique. In the other embodiment, the proposed method further adaptively adjusts compression ratio of the compressed feedback content in accordance to the prevailing channel quality. Further, for slow-varying MIMO channels, there is proposed another channel information feedback method which switches between a fixed sparcifying-basis and a signal-dependent sparcifying-basis.
31 Citations
19 Claims
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1. A channel information feedback method, adapted to a multi-antenna system, comprising:
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estimating, at a wireless communication device, parameters of a MIMO channel as a MIMO channel matrix based on signals received from a transmitter, and vectorizing the MIMO channel matrix into a first vector as an estimated MIMO channel representation; applying compressive sensing technique, at the wireless communication device, to take random measurements of the estimated MIMO channel representation by a pre-configured random matrix, so as to obtain compressive sensing measurements; and feeding back the compressive sensing measurements to the transmitter from the wireless communication device, wherein the step of applying the compressive sensing technique to take random measurements of the estimated MIMO channel representation by the pre-configured random matrix comprises;
reducing, at the wireless communication device, dimension of the first vector from N to M by multiplying the first vector with a M×
N pre-configured random matrix to obtain a second vector, wherein N>
M and M and N are positive integers;wherein the step of feeding back the compressive sensing measurements to the transmitter comprises;
transmitting, at the wireless communication device, the second vector to the transmitter;wherein before the step of reducing dimension of the first vector from N to M by multiplying the first vector with a M×
N pre-configured random matrix to obtain the second vector, the channel information feedback method further comprises;determining, at the wireless communication device, error rate based on the signals received from the transmitter; comparing, at the wireless communication device, the error rate with pre-determined multi-level thresholds; and
determining, at the wireless communication device, a compression ratio corresponding to the value of M, in accordance to the comparison result of the error rate and the pre-determined multi-level thresholds. - View Dependent Claims (2, 3, 6)
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4. The method of 2, further comprising:
transmitting, at the wireless communication device, an index indicating the adjusted compression ratio to the transmitter.
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5. The method of 2, wherein before the step of reducing dimension of the first vector from N to M by multiplying the first vector with a M×
- N preconfigured random matrix to obtain the second vector, the channel information feedback method further comprises;
determining, at the wireless communication device, whether detects any error; and determining, at the wireless communication device, a compression ratio corresponding to the value of M, in accordance to the determination result of detecting any error.
- N preconfigured random matrix to obtain the second vector, the channel information feedback method further comprises;
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7. A wireless communication device, comprising:
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a transceiver module, configured for receiving signals from a transmitter and feeding back information to the transmitter; a channel estimator, connected to the transceiver module, configured for estimating parameters of a MIMO channel as a MIMO channel matrix based on the signals received from the transmitter, and vectorizing the MIMO channel matrix into a first vector as an estimated MIMO channel representation; and a baseband processor, connected to the transceiver module and the channel estimator, configured for; applying compressive sensing technique to take random measurements of the estimated MIMO channel representation by a random matrix, so as to obtain compressive sensing measurements, and feeding back the compressive sensing measurements to the transmitter through the transceiver module; and reducing dimension of the first vector from N to M by multiplying the first vector with a M×
N random matrix to obtain a second vector, wherein N>
M and M and N are positive integers; andthe baseband processor is also configured for feeding back the second vector to the transmitter; wherein before obtaining the second vector, the channel estimator is configured for estimating instantaneous channel gain, and the baseband processor is configured for adaptively adjusting a compression ratio corresponding to the value of M in accordance to the instantaneous channel gain, and obtaining the second vector under the adjusted compression ratio. - View Dependent Claims (8, 9, 10, 11)
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12. A channel information feedback method, adapted to a multi-antenna system, comprising:
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transmitting, at a wireless communication device, signals to a receiver through a MIMO channel; receiving, at the wireless communication device, compressive sensing measurement parameters of the MIMO channel from the receiver; applying compressive sensing technique, at the wireless communication device, to recover the compressive sensing measurement parameters of the MIMO channel by using a N×
N sparcifying basis and a M×
N pre-configured random matrix, the step comprises;applying the compressive sensing technique, at the wireless communication device, to estimate a signal by using a first vector received from the receiver, the N×
N sparcifying basis and the M×
N pre-configured random matrix, wherein M<
N, N=Nr×
Nt, Nt is the number of transmitting antennas at the wireless communication device, and Nr is the number of receiving antennas at the receiver, where M, N, Nr, and Nt are positive integers; andrecovering, at the wireless communication device, a second vector from the N×
N sparcifying basis and the signal, and converting the second vector into an estimated MIMO channel matrix, wherein all entries of the estimated MIMO channel matrix are parameters of the MIMO channel;applying, at the wireless communication device, transmission parameters for a next session based on a recovered MIMO channel in transmission of signals; receiving, at the wireless communication device, an index indicating a compression ratio associated with the-first vector;
from the receiver, where the compression ratio is directly corresponding to a value of M; anddetermining, at the wireless communication device, a dimension of the M×
N pre-configured random matrix according to the compression ratio. - View Dependent Claims (13, 14, 15)
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16. A wireless communication device, comprising:
a transceiver module, configured for transmitting signals to a receiver through a MIMO channel and receiving signals from the receiver; and a communication protocol module, connected to the transceiver module, configured for; receiving compressive sensing measurement parameters of the MIMO channel from the receiver, applying compressive sensing technique to estimate a signal by using a first vector received from the receiver, a N×
N-sparcifying basis and a M×
N pre-configured random matrix,applying the compressive sensing technique to recover the parameters of the MIMO channel by using the N×
N sparcifying basis and the M×
N pre-configured random matrix,applying transmission parameters for a next session based on the recovered MIMO channel, wherein M<
N, N=Nr×
Nt, Nt is the number of transmitting antennas at the wireless communication device, and Nr is the number of receiving antennas at the receiver, where M, N, Nr, and Nt are positive integers,recovering a second vector from the N×
N sparcifying basis and the signal, and then converting the second vector into an estimated MIMO channel matrix, wherein all entries of the estimated MIMO channel matrix are parameters of the MIMO channel, andreceiving an index through the transceiver module from the receiver, wherein the index indicates a compression ratio associated with the first vector, and the compression ratio directly corresponding to a value of M; and
the communication protocol module is configured for further determining the M×
N pre-configured random matrix according to the compression ratio.- View Dependent Claims (17, 18, 19)
Specification