A Dynamic Downlink Load Control Scheme for WCDMA and HSDPA Systems

Chang Soon KANG  Junsu KIM  Dan Keun SUNG  

Publication
IEICE TRANSACTIONS on Communications   Vol.E92-B   No.6   pp.2327-2331
Publication Date: 2009/06/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.2327
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
Keyword: 
WCDMA,  HSDPA,  AMC,  downlink overload control,  

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Summary: 
Mutual interference among users can abruptly increase othercell interference and cause overload situation in coexisting WCDMA and HSDPA systems. Traffic overloading can degrade the performance of the systems. This letter proposes a new dynamic downlink load control (DDLC) algorithm to reduce performance degradation due to overload in the coexistence of WCDMA and HSDPA systems. With the proposed algorithm, the downlink load is controlled according to load states classified by two load-control thresholds, and traffic overloading is alleviated by dynamically adjusting the CQI values reported by users, based on the downlink load as well as channel variations. The proposed algorithm is simulated and results show that the DDLC scheme improves the performance of both WCDMA and HSDPA systems in terms of outage probability, total system throughput, and radio resource utilization.