Spreading code and interleaver design for grouped CDMA-IDMA (G-CDMA-IDMA) based on a single parameter

Abstract

In this paper, we propose a new technique to generate the spreading code for "spread spectrum", and the interleaver matrix for interleaving the data stream, by using a single parameter. This parameter is the initial state of a new chaotic system, called new logistic map (NLM). To evaluate the performances of our proposed technique (called CI-NLM technique), we use a new multiple access scheme known as groupedcode division multiple access-interleave-division multiple access (G-CDMA-IDMA), where the users are divided into smaller groups. When each group transmits at the same time, over the same frequencies and the same interleaver, and wecan separate the user's information of a group by using the spreading code (the same interleaver is assigned to all users of a group and the same spreading codes are reused in adjacent groups). By means of simulation results, we show that our proposed technique can be used to reduce the computational complexity, the bandwidth consumption, and achieve the same correlation and better BER performances compared to the conventional IDMA system.