System and method of dynamic switching of advanced calling feature in LTE networks

#The present application relates generally to wireless networks and, more specifically, to a wireless network providing Voice over LTE (VoLTE) service.

#Cell phone carriers operating Internet Protocol (IP) Multimedia Subsystem (IMS) networks are introducing new services to wireless subscribers. One service, known as Advanced Call Feature (ACF), enables a user equipment (e.g., mobile phone, laptop, tablet, etc.) to make Voice over LTE (VoLTE) phone calls. VoLTE uses IP packets to support voice calls, potentially offering much higher quality calls and faster set-up times, among other things, than traditional 2G services that provide circuit-switched voice calls.

#However, the quality and availability of VoLTE is determined by the quality of the coverage of the local LTE network. This means that a user equipment (UE) that is connected to an LTE network in a weak coverage area may attempt a VoLTE call even though the network conditions may not be sufficient to give the end-user the same good experience the mobile phone subscriber may be accustomed to with a legacy radio access technology (RAT), such as CDMA 1×RTT. This can result in dropped calls, muted audio, and distorted audio, among other things. Additionally, this may cause the subscriber to blame the mobile phone for the poor quality of the phone call, rather than the LTE network conditions.

#For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

#FIG. 1 illustrates user equipment in a coverage area in which VoLTE service is provided by an advanced radio access technology and conventional voice service is provided by a legacy radio access technology according to one embodiment of the disclosure.

#FIGS. 2A and 2B are flow diagrams depicting dynamic switching of Advanced Calling (DSAC) feature according to one embodiment of the disclosure.

#FIGS. 1 through 7, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably-arranged wireless user equipment.

#The present disclosure describes a new capability for wireless user equipment that provides a dynamic switching of the Advanced Calling Feature (VoLTE) service in weak LTE coverage areas. The DSAC service results in fewer dropped calls and improved audio quality for those users (or subscribers) who are in a weak LTE coverage area, while allowing the device to remain attached to LTE for packet switched data. The DSAC service implements service quality thresholds that allow the user equipment to switch in and out of VoLTE service based on the network RF conditions.

#FIG. 1 illustrates user equipment (UE) 121 in coverage area 100, in which VoLTE service is provided by an advanced radio access technology (RAT1) network and a conventional voice service is provided by a legacy radio access technology (RAT2) network according to one embodiment of the disclosure. Coverage area 100 includes base station (BS) 111, which is part of the RAT1 network and provides VoLTE service to UE 121. Coverage area 100 includes base station (BS) 112, which is part of the RAT2 network and provides a legacy voice service, such as 1×RTT CDMA) to UE 121. BS 111 and BS 112 are both connected to a communication backbone, which may include, for example, Internet protocol (IP) network 100 (hereafter, Internet 100) and/or a circuit-switched network (not shown), which may include a mobile switching center (MSC).