Equalizer development for wide-band 16 QAM/TDMA in land mobile communications

We developed an experimental equalizer for wide-band 16 QAM/TDMA in land mobile communications that works under frequency-selective fading environments, and performed an laboratory experiment. Frame synchronization is important for an equalizer to work properly. In conventional frame synchronization, false synchronization due to delayed-wave occurs under non-minimum-phase condition, leading to degraded performance. We propose a new frame synchronization method that examines the direct-wave and delayed-wave signal power ratio, and even under non-minimum-phase condition, can hold synchronization to the direct-wave, to maintain the equalizer performance. BER performance in the experiment is improved about 10 times at Eb/N0 equal to 20 dB with delay of 3 to 5 symbols in the maximum Doppler-frequency equal to 40 Hz.