Waveform Optimization for FBMC in a Multiple Access Communication Framework

Abstract

This paper presents a comprehensive framework for waveform optimization in synchronous, partially synchronous, and asynchronous multiple-access filter bank multicarrier (FBMC) systems. We introduce the harmonic mean of the subcarriers' signal-to-interference-plus-noise ratio (SINR) as the equivalent SINR (ESINR) to provide a tractable optimization metric that accurately reflects communication quality. Then, we formulate the joint transmit-receive waveform optimization as generalized Rayleigh quotient maximization problems, which enables efficient iterative solutions through the ping-pong optimized pulse shaping (POPS) algorithm. Our numerical results demonstrate that the POPS-FBMC framework effectively addresses frequency and time misalignment, as well as power imbalance between multiple access communications. POPS-FBMC maintains positive ESINR values even under a 20 dB power imbalance between users-where conventional cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM) fails completely. Our system reduces the size of the frequency guard band by at least 60% compared to current Wi-Fi systems, which makes it ideal for grant-free and sporadic traffic patterns.