The present invention makes it possible to increase a data rate between a transmitter and receiver using a multiple-input, multiple-output radio frequency channel. A multiple-stream, multiple-antenna receiver measures a composite channel between a multiple-antenna transmitter and a m
A method 600 of selecting an ARQ method for retransmitting a data frame based on an accumulated signal to noise ratio (SNR) of systematic bits in the data frame at a receiving unit 508. The sending unit 500 tracks the accumulated SNR of systematic bits by using channel SNR measurement