Abstract: In some embodiments, there are disclosed systems and methods in which, when a mobile device receives a message indicating that the mobile device is to release resources pertaining to a communication session for a voice call over an access network, the mobile device refrains from performing this action to allow for the possible arrival and processing of a delayed handover command. The arrival of the handover command causes the mobile device to handover to a second access network to continue the voice call using a second communication session. This may help address situations in which the handover command is delayed in the network and is therefore delayed in reaching the mobile device.

Abstract: A wireless communication network and a mobile device may support Circuit Switched (CS) and Packet Switched (PS) services. Some types of communication services (e.g. voice, text, data, etc.) may be supported using a CS service or using a PS service. In some embodiments, the PS service is an IMS service using Session Initiation Protocol (SIP) to provide a “CS-like” communication service such as voice or text message. According to the disclosure, a mobile device may detect that it is process data for the PS service. For example, a SIP component that supports the PS service may become inoperable. In response, the mobile device attempts to support the communication service using the CS service.

Abstract: A wireless communication network and a mobile device may support Circuit Switched (CS) and Packet Switched (PS) services. Some types of communication services (e.g. voice, text, data, etc.) may be supported using a CS service or using a PS service. In some embodiments, the PS service is an IMS service using Session Initiation Protocol (SIP) to provide a “CS-like” communication service such as voice or text message. According to the disclosure, a mobile device may detect that it is process data for the PS service. For example, a SIP component that supports the PS service may become inoperable. In response, the mobile device attempts to support the communication service using the CS service.

Abstract: In some embodiments, there are disclosed systems and methods in which, when a mobile device receives a message indicating that the mobile device is to release resources pertaining to a communication session for a voice call over an access network, the mobile device refrains from performing this action to allow for the possible arrival and processing of a delayed handover command. The arrival of the handover command causes the mobile device to handover to a second access network to continue the voice call using a second communication session. This may help address situations in which the handover command is delayed in the network and is therefore delayed in reaching the mobile device.