Adaptive MCS Selection in OFDM Systems Based on Channel Frequency Coherence

Abstract

This paper presents a joint adaptive modulation and coding (AMC) scheme, which exploits the coherence bandwidth of the wireless channel to divide the transmitted frame into independent sub-channels that correspond to the channel coherence bandwidth. This strategy is implemented for orthogonal frequency division multiplexing (OFDM) systems with channel state information (CSI) feedback. Low density parity check (LDPC) codes are utilized for encoding by employing signal-to noise ratio (SNR) dependent coding rates, as well as distinct modulation schemes to achieve adaptivity to time-varying channel conditions. The performance of the proposed system was tested on Rayleigh fading channels that exhibit frequency coherent bands. Numerical results obtained via simulation demonstrate that the throughput of the proposed system and bit error rate (BER) performance are better than previously suggested approaches.