A Novel Scattered Pilot Design for FBMC/OQAM Systems

Abstract: Filter bank multi-carrier with offset quadrature amplitude modulation (FBMC/OQAM) has been heavily studied as an alternative waveform for 5G systems. Its advantages of higher spectrum efficiency, localized frequency response and insensitivity to synchronization errors may enable promising performance when orthogonal frequency division multiplexing (OFDM) fails. However, performing channel estimation under the intrinsic interference has been a fundamental obstacle towards adopting FBMC/OQMA in a practical system. Several schemes are available but the performance is far from satisfaction. In this paper, we will show the existing methods are trapped by the paradigm that a clean pilot is mandatory so as to explicitly carry a reference symbol to the receiver for the purpose of channel estimation. By breaking this paradigm, a novel dual dependent pilot scheme is proposed, which gives up the independent pilot and derives dual pilots from the imposed interference. By doing this, the interference between pilots can be fully utilized. Consequentially, the new scheme significantly outperforms existing solutions and the simulation results show FBMC/OQAM can achieve close-to-OFDM performance in a practical system even with the presence of strong intrinsic interference.