When a fixed free-running crystal is used for sampling time generation at a DMT receiver, Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI) are introduced by sampling time error. The ICI becomes more serious as the DMT symbol length increases. In this letter, the effects of sampling clock offset are investigated in the time domain using a new notion of Inter-sample Interference (IsI) instead of ISI and ICI. Based on the IsI analysis, we propose a new frequency domain timing error correction scheme.

This letter presents a simple joint estimation method for residual frequency offset (RFO) and sampling frequency offset (STO) in OFDM-based digital video broadcasting (DVB) systems. The proposed method selects a continual pilot (CP) subset from an unsymmetrically and non-uniformly distributed CP set to obtain an unbiased estimator. Simulation results show that the proposed method using a properly selected CP subset is unbiased and performs robustly.