Performance analysis of orthogonal-code hopping multiplexing systems with repetition, convolutional, and turbo coding schemes

Abstract

In orthogonal-code hopping multiplexing (OCHM) systems, hopping-pattern (HP) collisions may degrade system performance. Previous studies on the effect of HP collisions in OCHM systems were based on computer simulations, and there was no mathematical analysis of the bit-error-rate (BER) performance. The HP collisions in OCHM systems differ from hits in frequency-hopping systems or intracell interference in direct-sequence code-division multiple-access (DS/CDMA) systems because they can effectively be controlled through synergy and perforation techniques. In this paper, we introduce a received-signal model for OCHM systems called a perforation-only model and analyze the BER performance for OCHM systems in both uncoded and coded environments. Repetition, convolutional, and turbo codes are considered in coded environments. Through the analysis of BER performance, OCHM systems can more clearly be characterized, and the allocated power at the base station (BS) can be estimated for OCHM systems. Furthermore, the user capacity is analyzed for a given channel coding scheme. The results show that the uncoded BER is saturated by the perforation probability, and the coded BER is degraded as the perforation probability increases. We investigate the allocated power at the BS according to the perforation probability and compare the user capacities of OCHM systems using the three different types of coding schemes.