Synchronization Sequence Design for FBMC/OQAM Systems

In this paper, we propose a new sequence generation methodology to make a constant amplitude zero autocorrelation (CAZAC) preamble available in offset Quadrature Amplitude Modulation-based filter bank multicarrier (FBMC) synchronization. The role of the new sequence is to compensate the filtering and symbol overlap of the FBMC structure so as to finally be able to make a CAZAC preamble in time domain. To derive the new sequence, we formulate a symbol overlap model that shows the relation between the new sequence and a CAZAC preamble. On the other hand, the offset modulation format is a constraint that needs to be considered in the design of the new sequence. By using a property of this offset modulation constraint, we derive a closed-form expression of the new sequence from the symbol overlap model. In addition, we extend an advanced model to create a pseudo-CAZAC preamble that is not data-dependent, thus enabling convenience of implementation. Simulation results show the superiority of the proposed model with respect to synchronization accuracy, out-of-band radiation, and peak to average power ratio. Moreover, we verify that the proposed model is well-suited for use in the cellular environment through complexity and resource efficiency comparisons.