Capacity and turbo equalization for truncated root‐raise cosine‐pulsed modulation systems in the presence of timing offset

Abstract

SummaryIn communication systems, in order to increase spectrum efficiency, pulses with limited bandwidth that meet the Nyquist zero intersymbol interference criterion are usually used for transmission. However, the truncated pulse is conducive to the realization of the partial response signal transmission system. The actual method is to cut the finite bandwidth pulse into a finite and sufficient length in the time domain. This will make the overall impulse response no longer meet the Nyquist criterion and at the receiving end will produce intentional intersymbol interference, so demodulation requires complex sequence detection. In this paper, we consider the truncated root raised cosine modulation system with timing offset and compare the channel capacity of partial response signals with different parameters. At the receiving end, demodulation uses the turbo equalization with different equalization methods to eliminate the intersymbol interference of partial response signals. Among them, we use fewer symbol paths in the BCJR algorithm to calculate the maximum posterior probability to construct low‐complexity equalization and compare according to the computational complexity and performance results of different equalizations.