Sampling Synchronization for OFDM-Based System with Unified Reference Clock

摘要

Due to the constraint of cost and size for mobile wireless communication terminals, many orthogonal frequency division multiplexing (OFDM) based systems required the same crystal driving the sampling and the channel frequency, which lead to the challenge of a more comprehensive sampling clock synchronization scheme needed. In this chapter, we proposed a two-stage scheme of sampling clock synchronization based on theoretical derivation: The preliminary sampling frequency offset(SFO) was jointly acquired with the carrier frequency offset by using the improved preamble-aided algorithm firstly. Secondly, the timing drift resulted from residual SFO and sampling timing error(STE) was derived together with performance analysis. The deviation properties of the estimation were achieved theoretically, which reveals that the variance of timing drift is in inverse proportion to SNR and grows linearly by square of the number of total subcarrier. The results of simulation show the proposed synchronization scheme can introduce preferable tracking and robust synchronizing performance for this kind of OFDM-based system.