A new tracking loop for direct sequence spread spectrum systems on frequency-selective fading channels

A new tracking loop is proposed for direct-sequence spread-spectrum signaling on a frequency-selective fading channel. By exploiting the inherent multipath diversity of the channel, the new tracking loop overwhelmingly outperforms the traditional noncoherent delay-locked loop (DLL) for all cases under consideration. Linear and nonlinear methods are employed to analyze the new tracking loop with perfect channel estimation. The performance degradation caused by imperfect channel estimation is determined by computer simulations. Over a range of signal-to-noise-ratios (SNRs) of practical interest, the simulation results show that the degradation is less than 2 dB.