Non-data-aided timing synchronization for cooperative MIMO OFDM systems

In cooperative multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems, signals transmitted from cooperating terminals arrive at the receiver on distinct timing due to diverse propagation delays. Therefore, timing synchronization is even more challenging in cooperative MIMO systems than in centralized MIMO configurations. Up to the present, various training sequence designs, along with synchronization algorithms, have been proposed. Among these data-aided approaches, a timing synchronization scheme utilizing unequal period synchronization patterns (UPSPs) was proposed. In this paper, from a non-data-aided perspective, we propose a generalized interleaved carrier assignment scheme that makes the resultant random OFDM data symbols themselves become UPSP-like, and develop a blind timing synchronization scheme accordingly. Simulation results show that the proposed non-data-aided approach with majority vote refinement (MVR) can achieve better performance than the original UPSP-based approach.