A Joint Source-Channel Code Modulation Scheme Based on Variable-Length Code and Doping Modulation

A joint source-channel code (JSCC) modulation scheme based on variable-length codes (VLCs) and doping modulation is proposed. The parameters of the VLC source encoder are optimized to provide good compression and error-correcting properties. And a doping modulation is designed to match the source encoder with the aid of extrinsic information transfer (EXIT) chart analysis so that a significant coding gain can be achieved by iterative decoding and demodulation at the receiver. Moreover, by using many-to-one mapping we optimize the distribution of the modulation symbols, and further attainable capacity gain can be achieved. The simulation results show that compare to a JSCC modulation scheme based on VLC and unity-rate code, the proposed scheme has 0.5dBgain over AWGN channel and 0.3dBgain over Rayleigh fading channel. And its performance has only 1.2dB and 2dB away from the Shannon capacity of AWGN and Rayleigh channels respectively.