A New Multi-Link Time-Reversal Prefilter Design for Indoor Wireless Communications

Abstract

A prefilter based on the time-reversal (TR) is proposed to control the multi-link interference (MLI) and the inter-symbol interference (ISI) for multi-link system. At first, we define a new parameter signal-to-sidelobe-plus-leakage ratio (SSLR) to represent the performance of the multi-link system. To improve the bit error rate (BER) performance, the proposed prefilter minimizes the MLI and the ISI and maximizes the peak power of received signal at the same time by maximization of the SSLR. We set an optimization problem to maximize the SSLR which is a quadratically constrained fractional quadratic problem. To solve the optimization problem, we use the epigraph form and the bisection method. Therefore, we find an ε-optimal solution which is a global optimal solution. Simulation results show that link interference power is reduced by the MLI-TR prefilter and the SSLR of the MLI-TR prefilter is higher than that of the conventional TR prefilter. Moreover, the BER performance of the MLI-TR prefilter is improved in overall signal-to-noise ratio range. INDEX TERMS Time-reversal prefilter, indoor radio communication, interference channels, signal processing, optimization.