The performance of multi-user cooperative diversity in an asynchronous CDMA uplink

Abstract--This paper investigates the impact of interuser non-orthogonality and asynchronous communication on the information-outage probability performance of multi-user decode-and-forward (DF) cooperative diversity in a code-division multiple-access (CDMA) uplink. Each user in the proposed system transmits its own data towards the base station and also serves as a relay for other users. We assume full-duplex communication so that each user can transmit and receive simultaneously at the same frequency. Each user attempts to decode the messages of a plurality of other users and forwards the superposition of multiple re-encoded and re-spread messages. Our cooperative scheme employs a sub-optimum decorrelating receiver to suppress the multi-user interference at both the base station and the relay-side. We evaluate the informationoutage probability performance of the proposed scheme in an underloaded, fully-loaded and overloaded CDMA uplink. We consider combining schemes at the base stati...

• Type: Journal
• Year: 2008
• Where: TWC
• Authors: Kanchan G. Vardhe, Daryl Reynolds, Matthew C. Valenti
• Keywords: Base Station, Information-outage Probability Performance, Probability Performance, TWC 2008