毫米波无线通信中的定时跟踪方案
Timing tracking methods in millimeter-wave wireless communications

为了解决毫米波无线通信中模数转换器（analog to digital converter，ADC）无法在接收信号上实现高倍的过采样以及多径影响所导致的定时跟踪问题，该文基于2倍过采样数据，根据相关波形，利用Farrow插值给出2种适用于多径信道的定时跟踪方案，分别在频域均衡之前和之后进行误差精补偿。仿真结果表明：在Rummler信道下，定时频偏为时钟频率的20×10-6、误比特率为10-5时，这2种方案的信噪比（signal-to-noise ratio，SNR）与无定时频偏时的只相差2.5 dB左右，说明这2种方案在多径信道下具有良好的定时跟踪性能。
Abstract：The timing tracking of millimeter-wave wireless communications is very challenging since the analog to digital converters (ADCs) cannot provide high oversampling on the received signals and the multi-path channel causes tracking problems. Two timing tracking schemes based on twice over-sampled data and the waveform of the correlation values using Farrow interpolation are described in this paper for multi-path channels. The first scheme compensates for the timing error before channel equalization while the other compensates afterwards. Simulations show that with a timing error of 20×10-6 and a bit error rate (BER) of 10-5, the difference in the signal-to-noise ratios (SNRs) between these two systems and a system with no timing error is about 2.5 dB less than with the Rummler channel. Thus, both schemes provide good timing tracking for multi-path channels.