Throughput enhancement scheme in an OFCDM system over slowly-varying frequency-selective channels

Abstract

We propose multilevel transmit power allocation (MTPA) scheme and outer-loop control scheme to increase bandwidth efficiency and to guarantee a required bit error rate (BER). The system considered is orthogonal frequency-code division multiplexing (OFCDM) under slowly-varying frequency-selective Rayleigh fading channels. In the proposed schemes, modulation level and transmit power for each subcarrier is simultaneously controlled corresponding to channel condition to maximize transmitted bits per symbol (BPS) while keeping both total transmit power and BER constant. Computer simulations elucidate that our proposed schemes are effective in terms of throughput and complexity. © Springer-Verlag Berlin Heidelberg 2005.