New frame synchronization technique for OFDM/OFDMA and MC-CDMA systems

In the context of orthogonal frequency division multiplexing (OFDM), most papers define OFDM symbol synchronization as frame synchronization. In this paper, a frame is defined as a block of several OFDM symbols in the time dimension. The main contribution of this work is to propose a novel, lowcomplexity, frame synchronization method for multi-carrier systems that does not require any transmission overhead; this increases the channel capacity, power and bandwidth efficiency. Also, it enables a flexible multiple-access scheme to be implemented in OFDM, whereby each user can have different frame size. The proposed frame synchronization method is compared with a conventional method using a preamble. Power compensation and frame averaging techniques are proposed to improve the performance of the frame synchronizer. The performance of the proposed frame synchronizer is evaluated over a Rayleigh fading channel for orthogonal frequency division multiple-access (OFDMA) and multi-carrier codedivision multiple-access (MC-CDMA) systems.