Threshold-free erasure decoded multicarrier local transmission over multipath channels

In order to exploit fully the frequency diversity benefits of multicarrier modulation (MCM), and the very nature of the frequency selective radio chan nel, we investigate an erasure decoded pi/4 QDPSK MCM (ED-MCM) by employing simple Hamming (block) code. We propose the threshold-free criteria, i.e. relative minimum receive power test (RMRPT) and relative maximum decision e rror test (RMDET) for erasure generation and evaluate ED-MCM's performance by applying these tests tn average received power, average decision error, instantaneous symbol/bit decision errors. At a normalized delay spread of 1 /64, computer simulation results indicate a coding gains of 6.0 - 7.0 dB wi th ED-MCM at a BER of 10(-3) RMDET/RMRPT based erasure decoding yields a 1. 5 - 2.5 dB improvement over the conventional forward error correction (FEC) decoding at a BER of 10(-5). The simulation results at other normalized de lay spreads, i.e., 1/32, 1/16 are also obtained. The erasure criteria (RMRP T and RMDET) applied to average values of received power/decision error yie ld consistently better performance over error only decoding. The results in dicate that the erasure decoding based on relative (threshold-free) measure s clearly promises an improved performance of the MCM system.