Low latency timing synchronization scheme for IEEE 802.11a/n/ac systems

This paper addresses the problem of timing synchronization at the receiver of an IEEE 802.11a/n/ac communications system. In such systems, typically with multiple antennas at the transmitter, cyclic delay diversity (CDD) is implemented in the transmitted signal to provide diversity and hence, performance improvement in the error rates. However, the use of CDD creates pseudo-multipaths which degrade the performance of conventional timing synchronization algorithms, due to the increased delay spread of the channel. This paper proposes a method that achieves fine timing synchronization with low latency in two concurrent steps. The proposed scheme first achieves a coarse synchronization point so that important receiver operations can first take place. A fine timing synchronization algorithm operates concurrently to achieve a more accurate synchronization point and, to avoid incurring additional latency, post-processing is performed on the frequency domain samples of the preambles to compensate for the difference in synchronization points. The proposed scheme is shown to achieve excellent packet error rate performance with low latency requirements.