Joint Symbol Timing and Channel Estimation for FBMC-OQAM Systems

Filter bank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) can achieve very low out-of-band radiation and is considered to be an important candidate waveform for future communication networks. However, the synchronization sequence design and channel estimation issues are complicated in FBMC-OQAM systems owing to the pulses overlap and the intrinsic interference. In this paper, we propose a new training sequence pattern with a high bandwidth efficiency. A pilot symbol and two auxiliary data symbols are used to generate a conjugate symmetric sequence in the time domain while protecting the pilots from the intrinsic interference. Thus, channel estimation can be performed directly by the pilots, and an auto-correlation symbol timing algorithm is introduced by exploiting the conjugate symmetry property. In addition, a pulse tail truncation method is proposed to improve the bandwidth efficiency for burst-mode transmission. Finally, some numerical simulation results are presented to validate the proposed symbol timing, channel estimation, and truncation methods in various scenarios.