1 Detectors and Asymptotic Analysis for Bandwidth-Efficient Space-Time Multiple-Access Systems Yi Wu * , Member, IEEE, Markku Juntti * , Senior Member, IEEE, and Teng Joon Lim † , Senior Member, IEEE * Centre for Wireless Communication, P.O. Box 4500 FIN-90014 University of Oulu, Finland Email:eewuy@ust.hk; markku.juntti@ee.oulu.fi † Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada Email:tj.lim@utoronto.ca Abstract In this paper, a narrowband multiple-channel transmission scheme with multiple transmit antennas is proposed and analyzed. The channelization is based on space-time signature matrices, which do not expand bandwidth, unlike conventional schemes such as code division or time division multiplexing (CDM or TDM). The channels can be used by multiple independent users in an uplink or downlink scenario (multiple access or broadcast channels respectively), or by one user in a multiplexing sce- nario. The data transmitted on each channel is convolutionally encoded, interleaved and then space-time block encoded before space-time channelization. Each channel has a unique interleaver and space-time signature, but the convolutional encoder and space-time block code (STBC) encoder can be identical across channels. It is shown that asymptotic single-user like performance can be achieved with optimal detection and decoding, in a Rayleigh fading channel. Practical receiver algorithms are developed based on the iterative (turbo) detection technique. The simulation results demonstrate that these suboptimal receivers achieve single-user performance at moderate signal-to-noise ratios, and moderate user loads. In This work was presented in part at the IEEE International Symposium on Information Theory, Chicago, USA, IL, July 2004. The research was supported by the National Technology Agency of Finland, Nokia, the Finnish Defence Forces, Elektrobit and Instrumentointi. July 21, 2005 DRAFT