Abstract—CDMA is the access technique adopted in the third generation wireless system. In this technique, all users share the same bandwidth simultaneously but with different codes. This sharing generates interferences that can reduce the overall throughput of the WCDMA network when using a weak code allocation algorithm. In this paper we propose a code management and allocation scheme that ensures to a great extend an unrestricted access to the Wideband Code Division Multiple Access (WCDMA) network and greatly reducing the fragmentation of the code tree. Rather than simply keeping the code tree as compact as possible by merely depending on the request rate, we design an improved Region Division Allocation (IRDA) of OVSF codes a scheme for OVSF code tree management for the universal mobile telecommunication system (UMTS) by considering characteristics of traffic and dynamic resource allocation (DRA) to make the management efficient and satisfy different quality-of-service (QoS) requirements requested by diverse multimedia. According to our proposal, users would not only be restricted to their pre-defined code region but are allowed to borrow from other code regions and return to their home code if released by initial users. The simulation result indicates that optimum and fair usage of the available code was achieved
Index Terms—Code blocking, fragmentation, OVSF Code, spreading factor, WCDMA.
Authors are with Beijing Univeristy of Post and Telecommunication. No: 10 Xitu Cheng Lu, Haidian District. Beijing-100876, China (e-mail: bkumar52@hotmail.com; jxiaojun@bupt.edu.cn; slsun@bupt.edu.cn).
Cite: Mala Umar Mustapha Bakura, Jing XiaoJun, and Sun Songlin, "An Improved OVSF Code Assignment Scheme at the Forward Link of WCDMA 3G System," International Journal of Machine Learning and Computing vol. 2, no. 2, pp. 150-155, 2012.