A novel synchronization method for bi-orthogonal modulation systems

A bi-orthogonal modulation system using a delay lock loop and a differential detector is proposed. Moreover, the bit error rate (BER) performance under complete synchronization, the synchronization performance, and the BER performance by taking account of the tracking error are evaluated by theoretical analysis. The proposed system uses concatenated sequences which consist of the two separate sequences, that is, an anterior sequence and a posterior sequence, as the spreading codes. Because the particular sequence always appears by multiplying the anterior sequence by the posterior sequence, the proposed system can extract the timing information from the received signal itself. Consequently, the BER performance of the proposed system is the same as the lower bound of the bi-orthogonal modulation system. It is found that the proposed system is superior to the conventional bi-orthogonal modulation system using the particular synchronizing code