Space time variable length coding for wireless multimedia communications

A binary space time variable length coding (STVLC) scheme is proposed for transmission of digital signals with non-uniform occurrence probability distributions in delay-sensitive wireless systems. The proposed STVLC scheme is a unified source coding, channel coding, and spatial diversity/multiplexing design. Specifically, two-dimensional variable length binary codewords in the space time domain are designed and modulated using binary phase shift keying (BPSK), and then transmitted diagonally across the space-time grid using multiple antennas. As the number of bits per codeword varies, by the nature of variable length coding, the number of activated transmit antennas, which equals the number of bits per variable length codeword, also varies. We show that our unified design approach effectively exploits the coding gain, power saving, diversity and multiplexing gain, and thus achieves good source symbol error performance.