Performance evaluation of a new semi-orthogonal spreading code in an AWGN channel

摘要

Code Division Multiple Access (CDMA) emerges as one of the efficient multiple access techniques that can serve a large number of users simultaneously over the entire available channel bandwidth. Each user in this access system is accompanied with a unique spreading code which acts as its signature code. As a matter of fact, researchers have tried to maximize the number of distinct spreading codes while keeping in mind that the cross-correlation value between any two code members should be as low as possible to ensure little multi-user interference. In this paper, an algorithm has been proposed which can generate a new type of spreading code, named as SemiOrthogonal Modified Large-set Kasami (SOMLK) sequence. Characteristic of our proposed code has been investigated by means of a number of performance parameters and subsequently been compared with other spreading codes. Finally, SOMLK sequence has been used as a signature code in a multi-user CDMA system under Additive White Gaussian Noise (AWGN) channel and the resulting Bit Error Rate (BER) performance has been studied for different values of Signal to Noise Ratio (SNR) along with other existing spreading codes.