A hardware testbed for UMTS/TDD joint detection base-band receivers

This paper describes a hardware platform that has been designed to validate joint detection receivers for UMTS/TDD. This testbed includes transmitters, a multipath baseband channel emulation and a receiver. The receiver includes channel estimation, multiuser detection (MUD) and channel turbo decoding. It consists of a set of DSP and FPGA boards host in a PC machine that achieves real-time computation of multiuser processing at 368 kbit/s (user rate). The flexibility of the platform enables various configurations: downlink (DL), uplink (UL) and various channel conditions. Joint detection (JD) based receivers have been tested on this platform. The first one performs the JD in the temporal domain, the second one in the frequency domain. Real-time performance, hardware complexity and performance improvement compared to the RAKE receiver are discussed in this paper.