Capacity analysis of the successive AF relaying aided cooperative DS-CDMA uplink

An amplify-and-forward (AF) based successive relaying aided network (SRAN) is designed for a multi-user spread-spectrum scenario conceived for noncoherent (NC) detection in order to convert the typical 50% half-duplex relaying-induced throughput loss to a potential user-load reduction of the CDMA system, where the NC detector allows us to avoid the extra power consumption imposed by channel estimation. With the same “green agenda” in mind, we limit the extra complexity imposed on the relay node (RN) by invoking the AF, rather than the more complex decode-and-forward protocol. We theoretically characterize the proposed AF based SRAN in the context of the DS-CDMA uplink by evaluating its noncoherent Discrete-input Continuous-output Memoryless Channel (DCMC) capacity. We demonstrate that the cooperative DS-CDMA uplink achieves a higher capacity gain with respect to its conventional direct transmission based counterpart, when the system has to support a high number of DS-CDMA users.