2008/10/04 by Pedram Pad, Mahdi Soltanolkotabi, Pad, Pedram +7
Computer Science · Engineering · Mathematics · #Advanced Wireless Communication Techniques #Advanced Wireless Network Optimization #FOS: Computer and information sciences #Information Theory (cs.IT) #Wireless Communication Networks Research #cs.IT #math.IT
paper · pdf · doi:10.48550/arxiv.0810.0763
arxiv created 2008/10/04 · openalex publication_date 2008/10/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper we introduce a new class of codes for over-loaded synchronous wireless CDMA systems which increases the number of users for a fixed number of chips without introducing any errors. In addition these codes support active user detection. We derive an upper bound on the number of users with a fixed spreading factor. Also we propose an ML decoder for a subclass of these codes that is computationally implementable. Although for our simulations we consider a scenario that is worse than what occurs in practice, simulation results indicate that this coding/decoding scheme is robust against additive noise. As an example, for 64 chips and 88 users we propose a coding/decoding scheme that can obtain an arbitrary small probability of error which is computationally feasible and can detect active users. Furthermore, we prove that for this to be possible the number of users cannot be beyond 230.