Design of unequal error protection for MIMO-OFDM systems

Most multimedia source data exhibit unequal bit error sensitivity. Therefore, it is desirable to design a system where important data should be recovered with high priority. In this paper, we present unequal error protection (UEP) schemes, which exploit differences in bit error protection levels of M-ary QAM symbols, in order to support multimedia transmission in orthogonal frequency division multiplexing (OFDM) systems over frequency selective fading channels. We introduce an UEP scheme which significantly improves the performance with multiple transmit antennas. Also, we propose a receiver based on two stage maximum likelihood detection (MLD) schemes which can approach the performance of a full search MLD receiver with much reduced computational complexity. Simulation results show that the proposed schemes achieve a significant performance gain over the conventional equal error protection (EEP) scheme.