Managing scrambling codes during serving radio network subsystem relocation

Abstract

The present invention provides a method and an apparatus for managing relocation of one or more scrambling codes in a spread spectrum wireless communications system. The method comprises detecting an indication for a serving radio network subsystem relocation that causes a user equipment to leave a first radio network controller and selectively transiting, through an intermediate transition, at least one scrambling code of the one or more scrambling codes associated with an uplink from the first radio network controller to a second radio network controller for the user equipment in response to the indication. The first radio network controller may maintain three pools of scrambling codes, namely, a first pool of one or more relocated scrambling codes (SCs), a second pool of one or more free scrambling codes and a third pool for each of one or more used scrambling codes. By avoiding an early reuse, an uplink scrambling code may be assigned to a particular UE because a target radio network controller, i.e., a new serving radio network controller may use the same scrambling code as long relocated user equipment maintains a current call. In this way, an uplink scrambling code defined for a serving radio network subsystem relocation procedure based on 3GPP standards may be consistent across disparate vendor solutions.