多频带OFDM超宽带系统同步及信道估计算法

针对标准多频带正交频分复用超宽带系统，基于前导训练序列研究其同步及信道估计算法。相关检测用取中点来减小粗定时误差范围。细定时利用系统零保护间隔的特点找相邻窗口最小能量比，对频偏不敏感且抗多径干扰。对定时位置进行修正，避免了信息数据的丢失及符号间串扰。采用基带数字域跳频解跳的机制，使载波频偏的影响归结为与单频带系统一致，简化了同步算法。仿真表明，在较恶劣的信道条件下，残余定时误差仍很小，并由信道估计及均衡有效的吸收，频率同步及系统差错性能良好。

Synchronization and channel estimation for MB-OFDM based UWB systems

An intact scheme of synchronization and channel estimation for the standard multi band orthogonal frequency division multiplexing (MB OFDM) based ultra wide band (UWB) system is presented. The midpoint of the correlation peak is considered as the coarse timing position to reduce the error range. Fine timing is achieved by searching the minimum energy ratio of adjacent data windows according to the zero padding characteristic. This scheme is neither sensitive to frequency offset nor to multipath. Revision of timing position is performed twice to prevent the loss of information data and inter symbol interference (ISI). Frequency hopping and de hopping are performed in baseband digital domain that the carrier frequency offset impact is equal to that of single band systems. Simulation results show that in the severe channel, the residual timing error can be kept at a small scale which can be compensated by channel estimation and equalization. The performances of frequency synchronization and system error rate are high.