Efficient frequency domain (fd) mmse equalization weight updates in a multi-stage parallel interference cancellation receiver

A multi-stage Parallel Interference Cancellation (PIC) receiver for use in a multi-antenna wireless communication unit to provide Frequency Domain (FD) Minimum Mean Squared Error (MMSE) equalization when the communication unit is operating in a wireless network that supports multiple transmission layers, wherein the multi-stage PIC receiver is configured to:

• perform initial interference suppression for a total signal received from all receive antennas in the communication unit, the initial interference suppression being performed at each transmission layer-specific detector unit in a first stage of the PIC receiver using transmission layer-specific initial equalization weights applied to the total signal, wherein the total signal includes all signals received by each receive antenna for all transmission layers at a predetermined subcarrier, and wherein the initial interference suppression provides a corresponding equalized layer-specific signal for each transmission layer;
• process at least one equalized layer-specific signal to obtain a cleaned-up version of the total signal as a result of initial interference cancellation performed at the first stage of the PIC receiver;
• determine transmission layer-specific updated equalization weights by using the transmission layer-specific initial equalization weights;
• and
• apply corresponding transmission layer-specific updated equalization weights to the cleaned-up version of the total signal through a second stage of the PIC receiver.

A wireless communication unit configured to operate in a wireless network that supports multiple transmission layers, the communication unit comprising:

• a plurality of receive antennas, wherein each receive antenna in the plurality of receive antennas is configured to receive signals for all transmission layers;
• and
• a multi-stage Parallel Interference Cancellation (PIC) receiver coupled to the plurality of receive antennas, wherein the multi-stage PIC receiver is configured to:
• receive a total signal from all receive antennas in the plurality of receive antennas, wherein the total signal includes all signals received by each receive antenna for all transmission layers at a predetermined subcarrier,
• perform initial interference suppression for the total signal at each transmission layer-specific detector unit in a first stage of the PIC receiver using transmission layer-specific initial equalization weights applied to the total signal, wherein the initial interference suppression provides a corresponding equalized layer-specific signal for each transmission layer,
• process at least one equalized layer-specific signal to obtain a cleaned-up version of the total signal as a result of initial interference cancellation performed at the first stage of the PIC receiver, and
• apply corresponding transmission layer-specific updated equalization weights to the cleaned-up version of the total signal through a second stage of the PIC receiver, wherein the second stage is coupled to the first stage and wherein the transmission layer-specific updated equalization weights are determined without inverting a covariance matrix associated with the cleaned-up version of the total signal.

A system comprising:

• a first communication unit configured to operate in a wireless network that supports multiple transmission layers;
• and
• a second communication unit configured to be in wireless communication with the first communication unit via the wireless network, wherein the second communication unit has a plurality of receive antennas, and wherein the second communication unit is further configured to:
• receive a total signal from all receive antennas in the plurality of receive antennas, wherein the total signal includes all signals received by each receive antenna for all transmission layers at a predetermined subcarrier,
• perform initial interference suppression for the total signal using transmission layer-specific initial equalization weights applied to the total signal, wherein the initial interference suppression provides a corresponding equalized layer-specific signal for each transmission layer,
• process at least one equalized layer-specific signal to obtain a cleaned-up version of the total signal, and
• apply corresponding transmission layer-specific updated equalization weights to the cleaned-up version of the total signal, wherein the transmission layer-specific updated equalization weights are determined without inverting a covariance matrix associated with the cleaned-up version of the total signal.