Robust Time Synchronization Algorithm for IEEE 802.11ac WLAN Systems

Soohyun JANG  Jaeyoung ROH  Seongjoo LEE  Yunho JUNG  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E98-A   No.1   pp.441-444
Publication Date: 2015/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E98.A.441
Type of Manuscript: LETTER
Category: Communication Theory and Signals
Keyword: 
CSD,  MIMO-OFDM,  time synchronization,  WLAN,  

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Summary: 
In this letter, a robust time synchronization algorithm is proposed for MIMO-OFDM based WLAN systems. IEEE 802.11ac MIMO-OFDM WLAN standard specifies that the preamble with cyclic shift diversity (CSD) scheme is used for time and frequency synchronization. However, since the CSD scheme introduces multiple cross-correlation peaks at the receiver, serious performance degradation appears if the conventional cross-correlation based algorithm is applied. In the proposed algorithm, the time synchronization error due to multiple peaks is compensated by adding the cross-correlation value to its reverse cyclic-shifted version. Simulation results show that the proposed algorithm achieves an SNR gain of 1.5 to 4.5dB for the synchronization failure rate of 10-2 compared with the existing algorithms.