Performance of an adaptive maximum-likelihood receiver for fast fading multipath channel

A receiver which utilizes a maximum-likelihood sequence estimator (MLSE) for application to the American Digital Cellular (ADC) system is described. A MLSE shows good performance for a static channel. However, for the fast time-varying channel like a mobile radio application, the tracking capability of a MLSE is a problem. The receiver consists of the adaptive MLSE having improved tracking properties, the carrier synchronization using a phase-locked loop (PLL) and the symbol synchronization which recover the optimum sample timing for the different delay of the multipath channel. Simulation results show that bit-error rates below 3% at all delay intervals of up to one symbol period can be achieved when E_b/N₀ is about 17 dB and the Doppler frequency is 80 Hz. The performance corresponds to a margin of more than 4 dB for the requirements