Use of synchronous code division multiple access techniques with short coding sequences in the development of a local communication network

Abstract

A local area communication network using code division multiple access (CDMA) techniques based on direct sequence spread spectrum modulation (DS-SSM) is presented. The wide bandwidth required by conventional CDMA systems is radically reduced in this network by using special short orthogonal coding sequences and thus allowing a much larger number of network users. More specifically, the proposed CDMA system for 15 users requires approximately 30 times less bandwidth than a conventional CDMA system of equivalent performance having the same number of users. A mathematical analysis of the multiplexing technique is also presented in order to clarify the design procedure of proper coding sequences. Computer simulation is used for the evaluation of the system performance in terms of the additive noise of the channel and the interference caused by the users of the network.