【摘要】 本文针对IEEE802.11a前导序列无法精确定时的缺点,设计了一种新的前导序列,能够通过平台检测实现数据到达预警,之后利用有尖锐峰值的共轭对称结构做精确定时,因此误捕获率低,且不受频率偏移的影响。针对LS算法未考虑噪声带来估计误差的缺点,改进算法将LS算法估计的频域信道传输函数转换到时域,在时域利用信道脉冲响应的有限性,消除一部分噪声,再将其变换到频域替代LS算法所估计的信道传输函数。仿真结果表明,改进算法的均方误差较LS算法约有8dB的性能增益。更多还原

【Abstract】 Considering the defect of inaccurate capture of timing instant based on the preamble structure of IEEE 802.11a,this paper proposes a new preamble structure which utilizes the monitor of the arriving of the plateau to detect packet and the structure of conjugate symmetry with impulse-like trajectory for fine timing synchronization,hence having a low probability of wrong capture and avoiding the influence of frequency offset. Since LS algorithm does not consider the estimation error imposed by noise,resulting in bad performance,our new algorithm first transfers the channel transfer function(CTF) in frequency domain estimated by LS algorithm to time domain and makes use of the limitation of channel impulse response(CIR) to reduce the impact of noise. Then we transfer it back to frequency domain to replace the previous CTF estimated by LS algorithm. Simulation results show that the mean square error(MSE) can be significantly improved by about 8dB compared with that of conventional LS scheme.更多还原