PDA detector For DS-CDMA cooperative system

This paper considers the uplink of a cooperative Code-Division Multiple-Access (CDMA) sys-tem where parts of mobile nodes serve as source nodes while the others serve as relay nodes at any instant in time. When the non-orthogonal spreading codes are adopted, Multiple Access Interference (MAI) will exist at both the relay nodes and the base node, causing diversity gain to diminish. To mitigate MAI and exploit full advantages of cooperation, the Probabilistic Data Association (PDA) is developed at the relay nodes and the base node. Simulation results demonstrate that some performance gains can be obtained by the PDA de-tector over the Minimum Mean Square Error (MMSE) detector at high Signal-to-Noise Ratio (SNR) and conversely at low SNR.