Coverage Shrinking and Available Data Rate Variations for 3G CDMA Mobile Cellular Systems

Yuh-Ren TSAI  Kai-Jie YANG  

IEICE TRANSACTIONS on Communications   Vol.E89-B   No.3   pp.739-747
Publication Date: 2006/03/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.3.739
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Network
mobile cellular,  cell coverage,  code division multiple access,  outage probability,  link adaptation,  

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In 3G CDMA mobile communication systems, high data rate services are essential for many key applications. When an MS approaches the cell border, link performance is degraded and more power should be allocated to maintain the link performance. Since the maximum available signal power is limited, the link adaptation mechanism may diminish the data rate to maintain link performance. This implies that the valid coverage shrinks when the data rate increases. The shrinking of valid coverage under a predetermined data rate will strongly impact on the reliability of high data rate services. In this work, the encoded bit error probabilities of 3G CDMA mobile communication systems, over large-scale and large-small-scale fading channels, were analyzed based on SGA and SIGA methods. Analytic methods were also proposed to investigate the issues of coverage shrinking and service data rate variations. Furthermore, the outage probability, cell coverage percentage and the staying probabilities of available data rates were well examined. The proposed analytic methods can be applied, as a preliminary research, to the design of cellular-system-related techniques, such as QoS control, available data rate prediction, power reservation, and service adaptation.