Title :
On bandwidth-efficient multiuser-space-time signal design and detection
Author :
Ng, Benjamin K. ; Sousa, Elvino S.
Author_Institution :
Dept. of Electr. & Comput. Eng., Toronto Univ., Ont., Canada
fDate :
2/1/2002 12:00:00 AM
Abstract :
Signals designed for transmission over multiple transmit antennas are capable for achieving significant capacity gain. Traditional approaches aim at improving the single-user link with a centralized control over the set of transmit antennas. In this paper, by considering a set of independent and synchronized users communicating with the base station on the up-link, the joint signal can be viewed as space-time coded signal without a centralized control. Co-channel/inter-antenna interference presents a major impairment that limits the capacity. We propose a novel multiuser signal structure called interference-resistant modulation (IRM) to improve performance without coding nor bandwidth expansion. IRM can also be combined with fading-resistant modulation or space-time coding to yield additional gain when each user employs multiple transmit antennas. We prove that, both analytically and by simulations, the IRM with maximum-likelihood (ML) detection achieves the single-user performance asymptotically. Furthermore, to reduce the prohibitive complexity posed by ML detection, we propose a simple minimum-mean-square-error based precombining group detector and an interference cancellation scheme. It is shown that the proposed detector combined with IRM provides significant improvement over previous approaches
Keywords :
antenna arrays; array signal processing; centralised control; cochannel interference; codes; interference suppression; land mobile radio; least mean squares methods; maximum likelihood detection; modulation; multiuser channels; radio links; radio receivers; signal synthesis; transmitting antennas; ML detection; MMSE based precombining group detector; bandwidth-efficient signal design; bandwidth-efficient signal detection; base station; centralized control; cochannel interference; fading-resistant modulation; interantenna interference; interference cancellation; interference-resistant modulation; maximum-likelihood detection; multiple transmit antennas; multiuser signal structure; multiuser-space-time signal design; multiuser-space-time signal detection; niinimum-mean-square-error; single-user performance; space-time coded signal; space-time coding; up-link; Analytical models; Bandwidth; Base stations; Centralized control; Detectors; Interference; Modulation coding; Performance analysis; Signal design; Transmitting antennas;
Journal_Title :
Selected Areas in Communications, IEEE Journal on