Patent ID: 9131412
Filing Date: 2015-09-08
Classification: H04W

Abstract:
1. A method, comprising: detecting a single radio voice call continuity activation event indicating a handover of control plane signaling radio bearers for a voice call of a user equipment between a packet switched domain and a circuit switched domain; consistent with a serving radio network subsystem relocation procedure, suspending the control plane signaling radio bearers; resetting the suspended control plane signaling radio bearers; and after the handover, resuming the suspended control plane signaling radio bearers in a domain handed over to, where resuming comprises protecting the control plane signaling radio bearers of the voice call in the domain handed over to using a security key that is used to cipher user plane radio access bearers for the voice call in the domain handed over to, and synchronizing a sequence number of the resumed control plane signaling radio bearers of the voice call, where the synchronizing comprises synchronizing a sequence number of the control plane signaling radio bearers with a sequence number of the user plane radio access bearers for the voice call in the domain handed over to, where the security key is mapped to a same security key used to protect the control plane signaling radio bearers of the voice call prior to the handover in a source one of the packet switched domain and the circuit switched domain.