Real-time RLS-MLSE equalizer implementation for application to PDC (Personal Digital Cellular)

This paper investigates the experimental performance of the recursive least square adaptive algorithm-maximum likelihood sequence estimation equalizer (RLS-MLSE) implemented in a single DSP for application to the Japanese PDC (Personal Digital Cellular) system (operating at 900 MHz) under a harsh frequency-selective-fading environment. Frame synchronization and automatic frequency control (AFC) play an important role in making the equalizer effective, because the performance impairment of those functions causes serious degradation of the equalizer performance. In order to improve the total system performance under frequency-selective-fading, we apply a new high precision frame synchronization scheme using the recursive least square (RLS) algorithm and also a new AFC algorithm scheme taking advantage of a replica of the distorted unique word (UW). In the Rayleigh faded two-wave model with one symbol delay, a 1% BER can be achieved at an Eb/N0 equal to 16.0 dB with a maximum Doppler frequency equal to 40 Hz