Asymptotically optimal power control in CDMA with random spreading and MMSE multiuser detector

• Published in: 2004 IEEE Infocom Vol. 2; pp. 1044 - 1054 vol.2
• Main Author: Rosberg, Z.
• Format: Conference Proceeding
• Language: English
• Published: Piscataway, New Jersey IEEE 2004
• Subjects: Applied sciences; Degradation; Detection, estimation, filtering, equalization, prediction; Detectors; Distributed control; Exact sciences and technology; Fading; Information, signal and communications theory; Land mobile radio cellular systems; Multiaccess communication; Power control; Power engineering and energy; Signal and communications theory; Signal, noise; Systems engineering and theory; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Wireless networks; Multiuser detection; Fading; Time variable channel; Outage; Wireless telecommunication; Mean square error; Random sequence; Power control; Optimal control; Synchronous transmission; Code division multiple access; Uplink; Signal detection; Asynchronous transmission
• ISBN: 0780383559; 9780780383555
• ISSN: 0743-166X
• DOI: 10.1109/INFCOM.2004.1356991

We derive two types of optimal uplink transmission power control in synchronous and asynchronous CDMA time varying fading channel with multiple user classes, random spreading sequences and MMSE multiuser detector. One optimal policy minimizes the outage probability subject to maximum average power budget and maximum transmission power constraints. The other minimizes the average power budget subject to maximum outage probability and maximum transmission power constraints. We show that for a system with a large number of users and a proportionally large processing gain, both optimal policies are threshold cut-off policies. We express the policies explicitly and show how to compute their outage probabilities.