Rate-adaptive convolutional coded fixed spreading length (CCFSL) scheme for multi-rate MC-CDMA

In this paper, a new rate-adaptive convolutional coded fixed spreading length (CCFSL) multi-rate transmission scheme is proposed for MC-CDAM system. By using rate-compatible punctured convolutional (RCPC) codes and nested codes, all lower rate users are rate-adaptively encoded to become virtual highest rate users, which significantly improves their spectral utilization efficiency. With this new scheme, great flexibility in rate matching can be achieved. An upper bound is derived for the performance in the correlated Rayleigh fading channel. Furthermore the BER performance versus signal-to-noise ratio (SNR) and interference-to-signal ratio (ISR) of this scheme are compared with the VFSL and block coded fixed spreading length (BCFSL) scheme by simulation.