An Improved Region Division Allocation of Orthogonal Variable Spreading Factor Code in the Forward Link of WCDMA Network

Unrestricted access to the Wideband Code Division Multiple Access (WCDMA) network depends on availability of and unrestricted access to Orthogonal Variable Spreading Code Factor (OVSF) codes. The OVSF codes, if not carefully assigned to users are easily exhausted. Here we propose an improvement to an existing algorithm, Region division Allocation and tagged it as Improved Region Division Allocation (IRDA) of OVSF codes. According to our algorithm, not only that a user uses codes within its allotted region but would be able to borrow channelization codes from other code regions. In situations where it borrows from other regions, our algorithm enables the user to return to its home code region as soon as it finds an available code. The simulation result indicates optimum and fair usage of the available code.