Frequency-domain timing synchronization for IEEE 802.11n communications systems

This paper addresses the problem of timing synchronization in an IEEE 802.11n-based multiple-input single-output (MISO) communications system. In IEEE 802.11n systems, cyclic delay diversity (CDD) is implemented to avoid the problems associated with the unintentional beamforming effect which occurs when scalar multiples of one signal combine destructively after being transmitted through different antennas. However, the use of CDD results in the creation of pseudo-multipaths which will degrade the performance of correlation-based timing synchronization algorithms commonly used in such systems, due to the increased delay spread of the channel. Thus, a frequency domain timing synchronization algorithm, which is robust to the increase in delay spread due to the presence of pseudo-multipaths, is proposed. The proposed algorithm achieves a higher probability of timing synchronization than correlation-based timing synchronization algorithms typically implemented.