LDPC coded adaptive multiresolution modulation for Unequal Error Protection

Wireless Communications system in the coming future will need to support a large amount of services, each with a different Quality of Service (QOS). This paper proposes a system model which uses Adaptive Multiresolution Modulation (AMM) of 16, 64 and 256 Quadrature Amplitude Modulation (QAM) along with Low Density Parity Check (LDPC) codes of different code rates as a Forward Error Correcting (FEC) code to provide UEP for the heterogeneous traffic and also for maintaining the (QOS) of the different services at the desired level. Comparing with previous works, the difference with the proposed system is that channel coding is accounted while determining the shape of QAM at which the system performs best. Also, a multiresolution modulation is designed which does not degrade the performance of the least important message as that of the most important one is increased. A BER performance gain of 36.6 dB arises for the high priority message with the proposed scheme when compared to a fixed modulation scheme with the same coding used.