Scrambling code planning and optimization for UMTS system

In this paper, the problem of scrambling code (SC) planning and optimization in 3G networks is addressed. Scrambling Codes are used to identify and distinguish cells from one another in WCDMA networks. These SCs are reported by the mobile users to the network to declare which cells they are able to connect to. Under the limitation of available SCs to be assigned to the cells we propose various allocation schemes that assign the scrambling codes according to the planner needs. In addition, a detection algorithm of SC clashes¹ has been developed and the recommended assignment is then proposed to decrease the overall interference. Our results were applied to a live WCDMA cellular network and the achieved performance benefit is presented.