Initial Synchronization for Multi-Cell OFDMA Systems

In this paper, a complete solution to the initial synchronization for multi-cell OFDMA (orthogonal frequency division multiple access) systems is proposed. The proposed method consists of the following operations: timing synchronization, fractional carrier frequency offset (CFO) estimation, fractional CFO compensation, and joint integer CFO and preamble index estimation. To estimate multiple fractional CFOs with pseudoperiodic preamble, we suggest an over-sampling approach. An ill-condition detection and noise suppression algorithm is also presented. For joint integer CFO and preamble index estimation, we use a differential detection based cross-correlation method. Simulation results have shown that the proposed method gives satisfactory performance for a wide SNR range even when the mobile station (MS) is on the cell boundaries.

[1]  Per Ola Börjesson,et al.  ML estimation of time and frequency offset in OFDM systems , 1997, IEEE Trans. Signal Process..

[2]  Alfred O. Hero,et al.  Space-alternating generalized expectation-maximization algorithm , 1994, IEEE Trans. Signal Process..

[3]  Hyung-Jin Choi,et al.  Robust OFDMA Frame Synchronization Algorithm on Inter-Cell Interference , 2006, 2006 Asia-Pacific Conference on Communications.

[4]  Jianzhong Zhang,et al.  Initial Synchronization for 802.16e Downlink , 2006, 2006 Fortieth Asilomar Conference on Signals, Systems and Computers.

[5]  P. Grünwald.  The Minimum Description Length Principle (Adaptive Computation and Machine Learning) , 2007 .

[6]  Marco Moretti,et al.  Integer frequency offset recovery in OFDM transmissions over selective channels , 2008, IEEE Transactions on Wireless Communications.

[7]  P. Grünwald.  The Minimum Description Length Principle (Adaptive Computation and Machine Learning) , 2007 .

[8]  Donald C. Cox,et al.  Robust frequency and timing synchronization for OFDM , 1997, IEEE Trans. Commun..

[9]  Michael D. Zoltowski,et al.  OFDM blind carrier offset estimation: ESPRIT , 2000, IEEE Trans. Commun..

[10]  Yu-Dong Yao,et al.  Low-Complexity Orthogonal Spectral Signal Construction for Generalized OFDMA Uplink With Frequency Synchronization Errors , 2007, IEEE Transactions on Vehicular Technology.

[11]  David W. Lin,et al.  Joint Detection of Integral Carrier Frequency Offset and Preamble Index in OFDMA WiMAX Downlink Synchronization , 2007, 2007 IEEE Wireless Communications and Networking Conference.

[12]  Yu-Dong Yao,et al.  Deterministic multiuser carrier-frequency offset estimation for interleaved OFDMA uplink , 2004, IEEE Transactions on Communications.