Interference mitigation techniques for asynchronous multiple access communications in SIMO FBMC systems

In this paper we derive linear equalizers for FBMC systems. We focus on the multiple access channel where signals transmitted by different users may have different carrier frequency offsets and time delays. Aiming at reducing the bandwidth requirements of the periodic ranging messages we formulate two SIMO solutions that are tolerant to time and frequency misalignments. Simulation-based results show that the same performance can be achieved in the BER range [10^-2, 10^-4] in comparison to an OFDM multi-user minimum mean square error receiver. Considering a guard interval between users, the BER range in which FBMC and OFDM perform equally can be broadened. However, the OFDM solution requires a complexity 8.6 times higher and its spectral efficiency is reduced by 0.72 b/s/Hz due to the cyclic prefix.