Achievable-SIR-based predictive closed-loop power control in a CDMA mobile system

Chung Ming Lau, W. M. Tam

Research output: Journal article publicationJournal articleAcademic researchpeer-review

15 Citations (Scopus)

Abstract

A power control algorithm with two prediction models based on an achievable signal-to-interference power ratio (SIR) has been proposed under a multipath Rayleigh fading environment in a code-division multiple-access (CDMA) mobile system. An achievable SIR is defined as the maximum-minimum SIR among all users at a particular time step. The corresponding mobile transmission powers are denoted as the "optimum transmission powers." In the individual power predictor (IPP) model, a linear transversal filter is assigned to each user. The output of the IPP, which is a linear combination of the optimum transmission powers of the mobile during the current and previous power measurement periods, predicts the optimum transmission power of the mobile in the next time step. In the global power predictor (GPP) model, a single predictor, constructed by a linear neural network, is used to predict the optimum transmission powers of all mobiles in the next time step. In both predictor models, the weights of the predictors are updated by using the recursive least squares algorithm. To further improve the performance, a reduced power-measurement period has been studied. Simulation results show that the proposed power control algorithm can achieve a lower outage probability and a smaller dynamic range of transmission power compared with a conventional power control scheme.
Original languageEnglish
Pages (from-to)720-728
Number of pages9
JournalIEEE Transactions on Vehicular Technology
Volume51
Issue number4
DOIs
Publication statusPublished - 1 Jul 2002

Keywords

  • Code division multiple access (CDMA)
  • Mobile communications
  • Power control

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Computer Networks and Communications

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