IEEE802.20 OFDMA系统的上行接入同步算法  

Novel synchronization algorithms for IEEE802.20 OFDMA uplink access system

作　　者：周玥[1] 张朝阳[1] 程鹏[1] 仇佩亮[1] 

机构地区：[1]浙江大学信息与电子工程学系,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2008年第11期1894-1899,1976,共7页Journal of Zhejiang University：Engineering Science

基　　金：浙江省科技计划资助项目(2005C21005);国家自然科学基金资助项目(60572115);浙江省自然科学基金重点资助项目(Z104252)

摘　　要：针对IEEE 802.20正交频分复用接入(OFDMA)工作模式,提出并比较了2种简单有效的上行接入同步算法:时域算法和频域算法,分别利用了时域和频域相关特性.2种算法均包含符号定时估计、载波频偏估计和发送功率估计.时域算法利用时域自相关、互相关运算和自适应门限来检测接入信号.时域算法的优点在于相关窗长度可以灵活调节.频域算法由于分离了接入子载波和数据子载波,接入信号受到的数据干扰小,比时域算法更为精确,且计算量更小.仿真结果表明,2种算法均在低信噪比、多个接入用户的情况下性能良好,具有较高的鲁棒性和检测效率,是适合于IEEE 802.20及其他OFDMA蜂窝系统的高效上行接入同步算法.Two simple and efficient synchronization methods were proposed and compared for orthogonal frequency division multiplexing access （OFDMA） uplink access systems prescribed by IEEE 802.20. The first algorithm takes correlation operation in time-domain, called time-domain algorithm. Correspondingly, the other algorithm is called frequency-domain algorithm. Both algorithms include the estimation of symbol timing, carrier frequency offset and transmitted power. In the time-domain algorithm, timing offset estimation is based on the auto-correlation and cross-correlation in time-domain, and an adaptive threshold is defined to detect transmitted access probes. The time-domain algorithm has the advantage of a flexible correlation window size. The frequency-domain algorithm is more accurate since it bears less interference by extracting the sub-carriers used for accessing from data sub-carriers. Moreover, the frequency-domain algorithm needs fewer computations since it shares the FFT calculations with the data demodulation process. Simulation confirmed that both methods perform well even in the condition of low signal-noise-ratio values and several simultaneous access users. Both algorithms are robust, time efficient and very feasible for OFDMA cellular systems, especially IEEE 802.20 OFDMA systems.

关 键 词：IEEE 802.20 正交频分复用接入 上行接入同步 时频域相关 

分 类 号：TN91[电子电信—通信与信息系统]