Channel information feedback method and wireless communication device using the same

A wireless communication device, comprising:

• 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;
• and
• the 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.

A channel information feedback method, adapted to a multi-antenna system, comprising:

• 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;
• and
• recovering, 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;
• and
• determining, at the wireless communication device, a dimension of the M×N pre-configured random matrix according to the compression ratio.

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, and
• receiving 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.