A Novel Superposition Multi Rate Coded Modulation (SMRCM)

This paper is concerned with the design of a wireless data transmission which provides Un-equal Error Protection (UEP). A novel Superposition Multi Rate Coded Modulation (SMRCM) system has been introduced. In the proposed SMRCM, the user data bit stream can be divided into two bit streams. The first bit stream represents the region of High Priority (HP), while the second represents the region of Low Priority (LP). These two bit streams are encoded, spread and interleaved separately. The resultant chip interleaved sequences are modulated and superimposed together to achieve UEP at the receiver side. A simple Chip-By-Chip (CBC) iterative Multi User Detection (MUD) strategy is used. In AWGN channel, the proposed SMRCM performance is better than Un-coded Superposition Modulation (USM) and Un-equal Error Protection Superposition Coded Modulation (UEP-SCM) by dB, dB respectively, but degraded by 0.3 dB compared with Equal Error Protection Superposition Coded Modulation (EEP-SCM) at . The performance is investigated over AWGN and Rayleigh fading channels in the presence of High Power Amplifier (HPA). KeywordsSCM; UEP; HPA; CBC Iterative decoding.