Wireless communications network incorporating voice over IP using shared supplemental spreading codes

摘要

Disclosed is a method and system thereof for transmitting a Voice over Internet Protocol (VoIP) packet over a primary channel and a supplemental channel belonging to a shared pool of supplemental channels in a wireless communications network such that Orthogonal Variable Spreading Factor (OVSF) codes associated with higher spreading factors (SF) may be used, thereby minimizing the adverse effects on system resources associated with implementing VoIP over downlink Dedicated CHannels (DCH). In the method and system, if an entire VoIP packet cannot be transmitted over a single transmission time interval on a primary channel, a specific supplemental channel (or code associated therewith) is assigned to a User Equipment (UE) to which the VoIP packet is intended. A portion of the VoIP packet is transmitted to the UE over a Dedicated Physical Data CHannel (DPDCH) on the primary channel, and another portion of the VoIP packet is transmitted to the UE over a DPDCH on the supplemental channel. The assigned specific OVSF code (or supplemental channel associated therewith) belongs to a set of supplemental OVSF codes assigned to the UE, and the set of assigned supplemental OVSF codes belongs to a shared pool of supplemental OVSF codes reserved at Node B. The identity of the assigned specific supplemental OVSF code used for the supplemental channel is indicated to the UE over a Dedicated Physical Control CHannel (DPCCH) on the primary channel. The UE examines the DPCCH on the primary channel to determine whether a specific supplemental channel (or code associated therewith) has been assigned to it. If a specific supplemental channel was assigned, then the UE will decode the data on the assigned specific supplemental channel along with the data on its primary channel. Otherwise, the UE will only decode the data on its primary channel.