Research Problem:

Frame/Symbol synchronization for IEEE 802.11a (OFDM-based) WLANs


OFDM is employed as the transmission technique in the IEEE 802.11a WLAN standard.  Frame synchronization in OFDM systems is very important since misalignment of the frame position leads to severe ISI.  In the IEEE 802.11a standard, a preamble is dedicated to various synchronization tasks.  However, there is no mention in the standard how to use the preamble to achieve synchronization.  In this study, we developed a wide range of frame synchronization algorithms for IEEE 802.11a WLANs that outperform the existing state-of-the-art algorithms in terms of performance, complexity and robustness to multipath.

Representative Publications:

Yik-Chung Wu, Kun-Wah Yip, Tung-Sang Ng and E. Serpedin, ``Maximum-Likelihood Symbol Synchronization for IEEE 802.11a WLANs on Unknown Frequency-Selective Fading Channels,'' IEEE Trans. on Wireless Communications, vol. 4, no. 6, pp.2751-2763, Nov. 2005.  [PDF]

Kun-Wah Yip, Yik-Chung Wu and Tung-Sang Ng, “Timing-synchronization analysis for IEEE 802.11a wireless LANs in frequency-nonselective Rician fading environments,” IEEE Transactions on Wireless Communications, vol. 3, no. 2, pp.387-394, Mar. 2004.   [PDF]