Study On Timing Recovery In Wireless Communication

Wireless channel fading results in inter-symbol interference which occurs in the received signal. Because ISI is an important factor that worsens the performance of receiver, T-tap equalizer is commonly used in wireless receiver. T-tap equalizer is very sensitive to timing phase, and this is an inherent defect of T-tap equalizer. This paper studies this problem and makes further improvements over some other methods in the literature. To eliminate the effect of timing phase to the performance of T-tap equalizer, fractionally spaced equalizer can be used, but this increases the receiver complexity. Therefore timing recovery is a better choice than FSE.The traditional timing recovery uses phase-locked loop circuit and is based on maximum-likelihood timing estimation. A novel timing recovery scheme, which is based on the maximization of the spectrum of the sampled received signal at thefrequency of f= 1/2T, is proposed. The digital differential filtering (DDF) which isused for sampled signal increases the timing component of processed signal. This method gets optimum sampling phase from the handled series using iteration algorithm. Timing recovery is completely achieved with software, and this is a highlight point compared with traditional method. Simulation results show that the proposed algorithm is robust to lower signal to noise ratio and deep fading channel.