An effective SINR mapping models for 256QAM in LTE-Advanced system

In this paper, we derive an effective SINR mapping algorithm based on Mutual Information (MI) Effective SINR Metric (ESM) model for 256QAM modulation system. Since recently 256QAM modulation is proposed in 3GPP LTE-A Rel.12 and IEEE 802.11ac standard, the design of Link-to-System (L2S) interface for 256QAM needs to be considered. Based on the Log Likelihood Ratio (LLR) receiver model, we derive the LLR probability density function (PDF) of each bit in the 256QAM modulation constellation, and approximate them as mixture Gaussian distributions. Then based on the MI ESM model definition, we compute the MI function of 256QAM by Monte Carlo integration, which can be used in the L2S interface of LTE-A or other 256QAM modulation based system. Numerical results demonstrate the accuracy of this model.