Pseudo-noise preamble based joint frame and frequency synchronization algorithm in OFDM communication systems

• Published in: Journal of systems engineering and electronics 2014-02, Vol.25 (1), p.1-9
• Main Authors: Jing, Qingfeng, Cheng, Ming, Lu, Yuping, Zhong, Weizhi, Yao, Hongwei
• Format: Article
• Language: English
• Subjects: Algorithms; Channels; Communication systems; Frames; Frequency synchronization; Interference; OFDM系统; Offsets; Orthogonal Frequency Division Multiplexing; 伪噪声; 同步算法; 序言; 快速傅立叶变换; 载波频率偏移; 通信系统; 频率同步
• ISSN: 1004-4132; 1004-4132
• DOI: 10.1109/JSEE.2014.00001

Frame and frequency synchronization are essential for orthogonal frequency division multiplexing （OFDM） systems. The frame offset owing to incorrect start point position of the fast Fourier transform （FFT） window, and the carrier frequency offset （CFO） due to Doppler frequency shift or the frequency mismatch between the transmitter and receiver oscil ators, can bring severe inter-symbol interference （ISI） and inter-carrier interference （ICI） for the OFDM system. Relying on the relatively good correlation charac-teristic of the pseudo-noise （PN） sequence, a joint frame offset and normalized CFO estimation algorithm based on PN preamble in time domain is developed to realize the frame and frequency synchronization in the OFDM system. By comparison, the perfor-mances of the traditional algorithm and the improved algorithm are simulated under different conditions. The results indicate that the PN preamble based algorithm both in frame offset estimation and CFO estimation is more accurate, resource-saving and robust even under poor channel condition, such as low signal-to-noise ratio （SNR） and large normalized CFO.