Efficient joint estimation of fine timing and channel impulse response for wideband wireless channels

Efficient joint time delay and channel estimation for wideband wireless channel measurement systems is investigated. Cyclic prefixed pilot segments are consecutively sent at the transmitter. The start position of the fast Fourier transformation(FFT) window is firstly determined according to the coarse synchronization at the receiver. Then, the accurate channel frequency response (CFR) is obtained using the modified least-square estimator and the following transform-domain filter. Next, with the estimated CFR, the time offset of the received pilot segments is estimated. Subsequently, the factional time delay of the received pilot segments is compensated. The channel estimator, the fine time delay estimator and the compensator are combined into the iterative coherent delay-locked loop (IC-DLL). Simulation results show that the proposed IC-DLL method significantly outperforms the non-coherent DLL.