An Energy Sequencing Based Partial Maximum Likelihood Detection Method for Space-Frequency Joint Index Modulation System

Abstract

In this paper, an energy sequencing based partial Maximum Likelihood (ML) detection algorithm is proposed for the complex characteristics of receiver detection in space-frequency joint index modulation system. This algorithm can solve the problems of high complexity from ML detection and poor Bit Error Rate (BER) performances by Minimum Mean Square Error (MMSE) detection. The major idea of the proposed algorithm is to demodulate the activated sub-carrier sequence number, antenna sequence number and constellation symbol step by step, where the sub-carrier sequence number is equalized with MMSE and the energy value of each sub-carrier is calculated and sorted. And the P value is set as the number of candidate sub-carriers. Finally, the sequence numbers of alternative sub-carriers, antenna serial numbers and constellation symbols are detected by ML. Simulation results show that the proposed algorithm can reduce both search range of traditional ML methods and the complexity according to the selection of P value. For example, when $P = 3$, the BER can be reduced to 10⁻⁴ at the SNR of 20 dB in the proposed algorithm.

This work was supported in part by the National Natural Science Foundation of China under Grant 61271262, and in part by the Natural Science Basic Research Plan in Shaanxi Province of China under Grant 2017JM6099, and in part by the Fundamental Research Funds for the Central Universities of China under Grant 300102248307.