An OVSF R-T-CCCA Assignment for WCDMA Systems to Reduce Code Blocking

Abstract

The proposed "Root-To-Code Compact Code Assignment" (R-T-CCCA) scheme for "Wideband Code Division Multiple Access" (WCDMA) system is proposed by using the "Orthogonal Variable Spreading Factor" (OVSF) code tree. In the previous "Compact Code Assignment" (CCA) algorithm [1], the codes of the OVSF are divided to groups according to the system capacity and the incoming call is treated by most congested group. In the proposed R-T-CCCA scheme, the codes are also divided into groups in the same way that in the CCA scheme, except that the proposed R-T-CCCA scheme check the capacity from the root to the desired vacant code, such that the capacity of the system that available after the assignment of the code is least fragmented than that in the CCA scheme with more reduction in code blocking comparable with the CCA scheme. This leads to increase the call treating capability of the WCDMA system.