Patent Application
20180337961
The disclosed embodiments relate generally to wireless communication, and, more particularly, to method of synchronization of UE capability and registration status when UE fails to notify network capability change.
The wireless communications network has grown exponentially over the years. A Long-Term Evolution (LTE) system offers high peak data rates, low latency, improved system capacity, and low operating cost resulting from simplified network architecture. LTE systems, also known as the 4G system, also provide seamless integration to older wireless network, such as GSM, CDMA and Universal Mobile Telecommunication System (UMTS). In LTE systems, an evolved universal terrestrial radio access network (E-UTRAN) includes a plurality of evolved Node-Bs (eNodeBs or eNBs) communicating with a plurality of mobile stations, referred to as user equipments (UEs). The 3rd generation partner project (3GPP) network normally includes a hybrid of 2G/3G/4G systems. With the optimization of the network design, many improvements have developed over the evolution of various standards.
As set forth in the 3GPP, IP Multimedia Subsystem (IMS) is a core network that provides IP multimedia services to user equipments (UEs) over an Internet Protocol (IP) network. Historically, mobile phones have provided voice call services over a circuit-switched (CS) network, rather than strictly over an IP packet-switched (PS) network. Alternative methods of delivering voice or other multimedia services over IP have become available on smartphones (e.g. VoIP or Skype), but they have not become standardized across the industry. IMS is an architectural framework to provide such standardization. IMS is able to communicate with UEs through different types of access network, such as a wireless local area network (WLAN), an Ethernet network, a packet data network (PDN), or another type of access network. IMS is a new way to dial PS call on LTE (Voice over IP or Voice over LTE) instead of fallback to 2G/3G legacy CS call.
Rich Communication Services (RCS) is a communication protocol between mobile-telephone carriers and between phone and carrier, aiming at replacing short message service (SMS) messages with a text-message system that is more rich provide phonebook polling (for service discovery), and transmit in-call multimedia. RCS combines different services defined by 3GPP and Open Mobile Alliance (OMA) with an enhanced phonebook. Another phone's capabilities and presence information can be discovered and displayed by a mobile phone. RCS reuses 3GPP specified IMS system as the underlying service platform taking care of issues such as authentication, authorization, registration, charging and routing.
Both IMS and RCS contain several a plication services such as voice call (VoLTE), SMS, instant message (IM), discovery presence (DP), etc. over the IP network. UE will send SIP REGISTER to the network to inform UE's capability. When UE cap change for an IMS registered UE, UE will send a new SIP REGISTER message the latest capability to the network. If the SIP REGISTER sent failed UE will start a timer to resend the SIP message. During the retransmission, me registration status between UE and the network is un-sync. As a result, the network may use wrong way to notify UE for acquiring service. In one example, the service attempt may fail. In another example, the service attempt may succeed if the network retries other UE supported way, but the performance is affected.
A solution is sought.
A solution for synchronizing capability and registration status between a user equipment (UE) and a network application server is provided. After a UE registers with an IMS/RCS server for SIP-based application services, the UE capability and registration status is synchronized between the UE and the network. Later, the UE capability may change and the UE will try to send a SIP message to the network with an updated UE capability. However, error may occur due to UE out of service or network error, which requires the UE to re-sync with the network. Upon detecting a re-sync condition, the UE will then trigger re-sending the SIP message to the network or releasing the PDN connection such that the updated UE capability and registration status will be synchronized with the network.
In one embodiment, a user equipment (UE) establishes a packet data network (PDN) connection for transmitting and receiving IP layer data in a mobile communication network. The UE registers with the network for a list of session initiation protocol-based (SIP-based) services. The UE detects a UE capability change of the list of SIP-based services and notifying the network on the UE capability change. The UE transmits a SIP message to re-sync with the network upon detecting a re-sync condition of UE capability between the UE and the network. In one example, the list of SIP-based services belongs to IP Multimedia Subsystem (IMS) application service. In another example, the list of SIP-based services belongs to Rich Communication Service (RCS) application service. In one scenario, the re-sync condition is detected when the UE is out of service and then returns to service when the UE capability changes. The UE sends the SIP message to the network immediately upon the UE returns to service to PUBLISH an updated service list. In another scenario, the re-sync condition is detected when the UE has not successfully updated its registration status after a predefined time threshold. The UE sends the SIP message to the network to release the PDN connection and to reestablish a new PDN connection to REGISTER with the updated service list.
Other embodiments and advantages are described in the detailed description below. This summary does not purport to define the invention. The invention is defined by the claims.
The accompanying drawings, where like numerals indicate like components, illustrate embodiments of the invention.
Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings.
As set forth in the 3GPP, IP Multimedia Subsystem (IMS) is a core network that provides IP multimedia services to UEs over an Internet Protocol (IP) network. IMS application service includes telephony, fax, email, Internet access, voice over IP, instant message, and videoconference. Similarly, Rich Communication Service (RCS) reuses 3GPP specified IMS system as the underlying service platform to provide enhanced messaging services. RCS works with text, images, video, group text messages, and location sharing. RCS also provides an enhanced phone book with service discovery.
Both IMS and RCS contain several application services such as voice call, SMS, IM, DP, etc. over the IP network. UE will send SIP REGISTER to the network to inform UE's capability. When UE capability change for an IMS/RCS registered UE, UE will send a new SIP REGISTER message with the latest capability to the network. If the SIP REGISTER sent failed, UE will start a timer to resend the SIP message. During the retransmission, the registration status between UE and the network is un-sync. As a result, the network may use wrong way to notify UE for acquiring service. In one example, the service attempt may fail. In another example, the service attempt may succeed if the network retries other UE supported way, but the performance is affected.
In accordance with one novel aspect, a solution of synchronizing with UE capability and registration status between the UE and the network application server is provided. As depicted in
Similarly, UE 201 has an antenna 235, which may transmit and receive radio signals. RF transceiver module 234, coupled with the antenna, may receive RF signals from antenna 235, convert them to baseband signals and send them to processor 232. RF transceiver 234 may also convert received baseband signals from processor 232, convert them to RF signals, and send out to antenna 235. Processor 232 may process the received baseband signals and invoke different functional modules to perform features in the UE 201. Memory 231 may store program instructions and data 236 to control the operations of the UE 201. At the network side, application server 203 maybe an IMS server or an RCS server that provides various IMS/RCS application services to UE 201.
UE 201 may also include a set of control circuits that may carry out functional tasks of the present invention. A UE capability synchronization module 290 may detect UE capability change and the un-sync status with the network and triggering corresponding actions accordingly to re-sync with the network. Capability synchronization module 290 may further comprise a PDN connection circuit 291 that may establish PDN connection for data/voice services over the IP network, a registration circuit 292 that may register and/or publish the UE capability, a service detector 293 that may detect UE capability change, and a sync status detector 294 that may detect the un-sync status of UE capability and such un-sync is caused by a recoverable or an unrecoverable error. If the error is recoverable due to out of service, then the UE can re-send SIP message to re-sync capability and registration status after recovery. If the error is unrecoverable, then the UE can release the PDN connection to force to reset capability and registration status.
In accordance with one advantageous aspect, upon detecting the re-sync condition, e.g., UE RCS capability change and UE returns to service from out of service, the UE immediately sends a new SIP PUBLISH message to the network such that the RCS capability and registration status between the UE and the network is synchronized right away to avoid potential error. Otherwise, when the UE returns to service, the network still thinks that the UE has IM capability and may send an instant message to the UE. As a result, the IM service attempt may fail. By immediately resending a new SIP PUBLISH message upon the UE returning to service regardless of the timer expiry status, the potential service error can be avoided to improve performance and user experience.
In accordance with one advantageous aspect, upon detecting the re-sync condition, e.g., UE IMS capability change and network error for failing to register the updated capability after a predefined time threshold, the UE releases the PDN connection such that the IMS capability and registration status between the UE and the network is forced to be reset and then re-synchronized to avoid potential error. Otherwise, when another user dials an MT call, the network still thinks that the UE has VoLTE capability and may send an INVITE message to the UE for the MT VoLTE call. As a result, the VoLTE service attempt may fail. By forcing to release the PDN connection upon detecting the unrecoverable network error for registration, the potential service error can be avoided to improve performance and user experience.
Although the present invention has been described in connection with certain specific embodiments for instructional purposes, the present invention is not limited thereto. Accordingly, various modifications, adaptations, and combinations of various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.
