Maximizing the Effective Channel Capacity of Power Controlled WCDMA Systems under Rayleigh Fading Environments

Jiabin LIU  Shihua ZHU  Wenyuan LI  

IEICE TRANSACTIONS on Communications   Vol.E89-B   No.3   pp.879-885
Publication Date: 2006/03/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.3.879
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Terrestrial Radio Communications
channel capacity,  power control,  WCDMA,  Rayleigh fading,  

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This paper studies the optimization of the effective channel capacity of wideband code division multiple access (WCDMA) systems under Rayleigh fading environments. Firstly, the results for Shannon capacity of fading channels with channel side information are reviewed, where the capacity is achieved by using an optimal power control scheme. Secondly, an optimal interference threshold is set for a given system outage probability Pout to minimize total interference. Finally, the effective channel capacity of WCDMA is defined and a target SIR level γ* is derived with the Lagrangian multiplier method to maximize the effective channel capacity. It is shown that is dependent on the power control interference ratio (PCIR) ρ, the number of diversity paths identified by the receiver M, and the outage probability of the system. Simulation results are provided to validate the theoretical deductions. We conclude that the total effective channel capacity will be maximized as long as M4, and ρ0.5 for a proper value of .