MMSE multiuser detection for uplink DS-CDMA with regenerative cooperative relaying

• Main Author: Liu, Yan.
• Other Authors: Gong Yi
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems
• Online Access: http://hdl.handle.net/10356/40251
• Institution: Nanyang Technological University

To meet contemporary and future demand for high speed and good quantity in communication transmission, advanced algorithms and techniques has been greatly studied and employed. In wireless mobile communication various forms of diversity has primary importance. Cooperative diversity transmission investigated in this paper is a kind of spatial diversity. We consider the MMSE Multiuser detection for Uplink DS-CDMA with regenerative cooperative relaying. Decode and forward (DF) relaying transmission is employed for synchronous Direct Sequence Code Division Multiple Access (DS-CDMA) systems. We focus on three cooperation strategies: 1. each user helps all other users (All-cooperation), 2. each user helps all successfully decoded users (Suc-cooperation), 3. each user helps a user with maximal observed signal to interference plus noise ratio (SINR), (Max-cooperation). We design MMSE detectors at the user-relays and at the destination node and evaluate the bi-error-rate (BER) performance. Simulation results within the above scope give that with user cooperation the BER is better than direct transmission. Max-Cooperation achieves the lowest BER among the three methods. When the number of users increases, the BER performance with direct transmission gets worse, but the BER performance of Max-Cooperate improves significantly. For the All-Cooperate and Suc-Cooperate selection strategies, the number of users does not have much impact on the BER performance.