On a frame synchronization scheme for MC-CDMA systems in up-link asynchronous channels

We propose a frame synchronization scheme for multi-carrier code division multiple access systems in up-link asynchronous channels. We introduce a time domain sequence called as TD (transform and despread) sequence utilizing user specific spreading code. A TD sequence is used as coefficients of a TD filter whose output corresponds to the result of transforming an incoming signal into frequency domain equivalents and despreading it. The frame synchronization process is divided into data aided acquisition phase and non-data aided tracking phase. TD sequences appropriate for each phase are proposed. By finding the instance of the maximum output of TD filter for target user, frame synchronization for the target user´s signal could be achieved. Computer simulation shows that the proposed frame synchronization scheme could be used effectively in asynchronous transmission environments