Patent Publication Number: US-11051218-B2

Title: Management of an internet protocol multimedia subsystem (IMS) media session for user equipment (UE)

Description:
RELATED CASES 
     This United States patent application is a continuation of U.S. patent application Ser. No. 15/071,539 that was filed on Mar. 16, 2016 and is entitled “A LONG TERM EVOLUTION (LTE) MOBILITY MANAGEMENT ENTITY (MME) MANAGEMENT OF AN INTERNET PROTOCOL MULTIMEDIA SUBSYSTEM (IMS) MEDIA SESSION SERVICE LEVEL FOR A USER EQUIPMENT (UE).” U.S. patent application Ser. No. 15/071,539 is hereby incorporated by reference into this United States patent application. 
    
    
     TECHNICAL BACKGROUND 
     Wireless communication systems provide User Equipment (UE), such as smartphones, tablet computers, and other media devices, wireless access to communication services and allow users to move about and communicate over the air with access communication networks. Data communication networks, such as Long Term Evolution (LTE), exchange data packets with UEs to provide services, such as internet access, media streaming, voice calls, and text messaging. 
     Using LTE, a UE detects, attaches to, and registers with an LTE base station, wherein the LTE base station serves as the access point into an LTE wireless network to provide access to LTE network elements, such as a Serving Gateway (S-GW), Mobility Management Entity (MME), Packet Data Network Gateway (P-GW), Policy and Charging Rules Function (PCRF), and other LTE network elements. The UE can register with the LTE base station when the UE is powered-on or when the UE moves into a coverage area of the LTE base station. LTE base stations may include evolved NodeBs (eNodeBs), mini-macrocells, picocells, femtocells, and various other LTE base station capable of providing a UE access to the LTE wireless network. 
     The UE also typically registers with an Internet Protocol Multimedia Subsystem (IMS) to facilitate the exchange of Internet Protocol (IP) packets between UEs for media sessions and other data transfer services. The UE registers an IP address with the IMS systems over the IP access networks and use the registered IP address to exchange messaging for the IP communication sessions. A UE may register with an IMS system directly using various access systems, including LTE, Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), Ethernet, and other access systems. 
     Enhanced communication services may be available for some LTE base stations. These enhanced services may include Carrier Aggregations, beamforming, Multiple Input Multiple Output (MIMO), and backhaul services. These enhanced services can often extend or enhance a service level available for an IMS media session for a UE, such as Voice over LTE (VoLTE) calls or Video over LTE (ViLTE) calls. Unfortunately, there is no efficient and effective way to modify service levels for an IMS media session when a UE is handed-over between LTE base stations having different enhanced service capabilities. 
     Technical Overview 
     A data communication system delivers voice-conferencing and video-conferencing to User Equipment (UE). A wireless communication network establishes a signaling bearer between the UE and an Internet Protocol Multimedia Subsystem (IMS). The IMS initiates a video-conference bearer for the UE over the wireless communication network. The wireless communication network exchanges video data over the video-conference bearer using Carrier Aggregation (CA). In response to a UE handover to a target wireless access node, the wireless communication network signals the IMS to convert the video-conference bearer into a voice-conference bearer based on Carrier Aggregation (CA) technology at the target wireless access node. The IMS initiates a voice-conference bearer for the UE over the wireless communication network. The wireless communication network exchanges voice data over the voice-conference bearer. After another handover, the wireless communication network and the IMS may convert the voice-conference bearer back into a video-conference bearer. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-3  illustrate a Long Term Evolution (LTE) communication network to manage a service level for an Internet Protocol Multimedia Subsystem (IMS) media session for a User Equipment (UE). 
         FIGS. 4-6  illustrate an LTE communication network to manage a service level for an IMS media session for a UE. 
         FIG. 7  illustrates an LTE MME to manage a service level for an IMS media session for a UE. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-3  illustrate LTE communication system  100  to manage a service level for an Internet Protocol Multimedia Subsystem (IMS) media session for a User Equipment (UE). LTE communication system  100  includes UE  101 , LTE access nodes  110 - 111 , Mobility Management Entity (MME)  120 , IMS  130 , and a Media Application Server. UE  101  and LTE access node  110  communicate over wireless link  150 . UE  101  and LTE access node  111  communicate over wireless link  151 . LTE access node  110  and MME  120  communicate over communication link  152 . LTE access node  111  and MME  120  communicate over communication link  153 . MME  120  and IMS  130  communicate over communication link  154 . IMS  130  and the Media Application Server communication over communication link  155 . 
     In operation, MME  120  manages a service level for an IMS media session for UE  101 . The IMS media session may be a conversational voice call, a conversational video call, media streaming, internet access, or some other IMS media service. In some examples, the IMS media session comprises a Voice over LTE (VoLTE) media session. In other examples, IMS media session comprises a Video over LTE (ViLTE) media session. The service level may be associated with the type of IMS media session, such as a conversational voice call. The service level may also be associated with a level of quality for the IMS media session, such as a High Definition (HD) conversational voice call. 
     MME  120  exchanges first control data with UE  101  to establish an IMS signaling bearer and a media session bearer. The first control data may be a codec, bit rate, Quality of Service (QoS) level requirements, or some other service level indicator. The first control data may be used as part of the IMS registration process to set up default bearers for UE  101 , such as a QoS Class Identifier (QCI)  5  to exchange SIP signaling messages. UE  101  may be capable of establishing multiple bearers. 
     The first control data may characterize service level for the IMS media session over LTE access node  110 . The first control data may also include a Radio Access Technology (RAT) type, a Packet Data Network (P-GW) identifier (ID), a Policy Charging Rules Function (PCRF) ID, a UE ID, or some other data that characterizes the IMS media session over LTE access node  110 . 
     MME  120  identifies a UE  101  hand-over between LTE access nodes  110 - 111  during the IMS media session and determines an access technology capabilities difference between LTE access nodes  110 - 111 . MME  120  may determine the access technology capabilities of LTE access node  110  and LTE access node  111  by transferring a request message to LTE access nodes  110 - 111  and receiving a response message from LTE access nodes  110 - 111  indicating the access technology capabilities. MME  120  may also determine access technology capabilities of LTE access nodes  110 - 111  based on data stored in MME  120  or by querying a Home Subscriber System (HSS). 
     The access technology capabilities difference may be based on LTE access node  111  capabilities to utilize beamforming services, Multiple Input Multiple Output (MIMO) services, Carrier Aggregation services, backhaul services, or some other service that may be available on LTE access node  110  and not on LTE access node  111 , or vice versa. The access technology capabilities difference between LTE access node  110  and LTE access node  111  may be due to LTE access node  110  and LTE access node  111  being a different type of LTE access node, such as an eNodeB, a picocell, a mini-macro cell, or some other LTE access node capable of exchanging data between UE  101  and MME  120 . 
     MME  120  determines when the service level for the IMS media session should be modified based on the access technology difference and exchanges service modification data with IMS  130 . MME  120  may determine that the service level for the IMS media session should be modified based on an upgraded service or downgraded service level. In some examples, MME  120  determines when the service level for the IMS media session should be modified based on the access technology difference by MME  120  exchanging session modification data with a PCRF. 
     In other examples, MME  120  may determine that the service level for the IMS media session should be modified and notify a Telephony Application Service (TAS) in IMS  130  to modify the data. In other examples, MME  120  may transfer a notification message to IMS  130  indicating the technology difference between LTE access node  110  and LTE access node  111  and the TAS in IMS  130  may determine whether the service level for the IMS media session should be modified based on the access technology difference. In some examples, IMS  130  may notify the Media Application Server of the IMS media session modification for UE  101 . 
     MME  120  exchanges second control data with UE  101  to indicate a modification to the service level for the IMS media session. The second control data may be a codec, bit rate, QoS level requirement, or some other service level indicator. The second control data may characterize service level for the IMS media session over LTE access node  111 . MME  120  may exchange second control data with UE  101  by transferring a request to modify the service level for the IMS media session in a Non Access Stratum (NAS) message. In some examples, MME  120  exchanges the service modification data with IMS  130  by exchanging Diameter Application Protocol messaging. In other examples, UE  101  may receive the second control data in a SIP message transferred by IMS  130  indicating the request to modify the service level for the IMS media session. 
       FIG. 2  illustrates a flow diagram of LTE communication system  100  to manage a service level for an IMS media session for a UE. MME  120  exchanges ( 201 ) first control data with UE  101  to establish an IMS signaling bearer and a media session bearer. MME  120  identifies ( 202 ) a UE  101  hand-over between LTE access nodes  110 - 111  during the IMS media session and determines ( 202 ) an access technology capabilities difference between LTE access nodes  110 - 111 . MME  120  determines ( 203 ) when the service level for the IMS media session should be modified based on the access technology difference. MME  120  exchanges ( 204 ) service modification data with IMS  130 . MME  120  exchanges ( 205 ) second control data with UE  101  to indicate a modification to the service level for the IMS media session. 
       FIG. 3  illustrates LTE communication system  100  to manage a service level for an IMS media session for a UE. MME  120  exchanges first control data with UE  101  over LTE access node  110 . UE  101  also exchanges LTE signaling with MME  120  and IMS signaling with IMS  130  to establish an IMS media session. For example, UE  101  may register with MME  120  and IMS  130  over LTE access node  110 , and establish an IMS signaling bearer, such as a QCI  5 . UE  101  may then initiate an HD conversational video call with a destination UE and establish a media session bearer for the HD conversational video call, such as a QCI  2 . In this example, MME  120  and UE  101  may exchange additional data over LTE access node  110  such as a RAT type, codecs, bits rates, and other control data to establish the conversational voice call for UE  101 . 
     MME  120  then identifies a UE hand-over between LTE access nodes  110 - 111  during the IMS media session and determines an access technology capabilities difference between LTE access nodes  110 - 111 . For example, LTE access node  110  may determine that UE  101  is moving out of a service area served by LTE access node  110  and transfer an instruction to UE  101  to attach to LTE access node  111 . UE  101  may then attach to LTE access node  111  which would transfer a notification message to MME  120  indicating that UE  101  has been handed-over from LTE access node  110  to LTE access node  111 . In this example, MME  120  may determine that LTE access node  110  had beamforming capabilities and LTE access node  111  does not have beamforming capabilities based on data stored in MME  120 . Beamforming uses multiple transmitting antennas to provide increased power for particular communications which may result in higher throughput signaling. Therefore, LTE access node  111  may not be capable of maintaining the service level required for the HD conversational video call for UE  101 . 
     MME  120  determines when the service level for the IMS media session should be modified based on the access technology difference and exchanges service modification data with IMS  130 . For example, if MME  120  determines that LTE access node  111  does not have beamforming capabilities and cannot maintain the service level required for the HD conversational video call for UE  101 , MME  120  may determine that the service level should be modified to maintain a standard, non-HD conversational video call for UE  101 . In this example, MME  120  may exchange downgrade modification data with IMS  130  using Diameter Application Protocol messaging. 
     MME  120  then exchanges second control data with UE  101  to indicate a modification to the service level for the IMS media session. For example, MME  120  may transfer second control data in a NAS message to UE  101  indicating a second codec data set and bitrates to be used for the standard, non-HD conversational video call. In this example, IMS  130  may also notify the Media Application Server of the service level modification by transferring modification data to the Media Application Server. 
       FIGS. 4-6  illustrate LTE communication system  400  to manage a service level for an IMS media session for a UE. LTE communication system  400  is an example of LTE communication system  100 , although LTE communication system  100  may use alternative configurations and operations. Referring to  FIG. 4 , LTE communication system  400  includes UE  401 , picocell  410 , eNodeB  411 , an LTE network, IMS  430 , and a Media Application Server. The LTE network includes MME  420 , an HSS, a Serving Gateway (S-GW), a P-GW, and PCRF  421 . The IMS system includes a Proxy Call Session Control Function (P-CSCF), a Interrogating Call Session Control Function (I-CSCF), Serving Call Session Control Function (S-CSCF), and TAS  430 . 
       FIG. 5  illustrates an operation of LTE communication system  400  to manage a service level for an IMS media session for UE  401 . In operation, MME  420  exchanges LTE signaling having first codec data with UE  401  over picocell  410 . UE  401  also exchanges IMS signaling with IMS  430  over picocell  410  and establishes IMS bearers, such as a QCI  5 . In this example, UE  401  initiates a ViLTE call but since picocell  410  does not have Carrier Aggregation, picocell  410  is unable to provide the level of service required to establish the ViLTE call. Therefore, a VoLTE call is established instead. In a next operation, UE  401  is handed-over from picocell  410  to eNodeB  411  and eNodeB  411  notifies MME  420  of the hand-over. 
     In response to identifying that UE  401  has been handed over from picocell  410  to eNodeB  411 , MME  420  queries the HSS and determines that eNodeB  411  has Carrier Aggregation capabilities. MME  420  then determines that eNodeB  411  is capable of providing the service level required for the initiated ViLTE call and exchanges session modification data with PCRF  421  to determine if the service level should be modified. In response to determining that the service level should be modified, MME  420  then exchanges modification data with IMS  430  over PCRF  421 . IMS  430  also notifies the Application Media Server to of the modified service level. MME  420  then exchanges second modified codec data with UE  401  over eNodeB  411  using NAS messaging. In a final operation, an IMS ViLTE media session is established between UE  401  and the destination UE over eNodeB  411 . 
       FIG. 6  illustrates another operation of LTE communication system  400  to manage a service level for an IMS media session for a UE. In operation, MME  420  exchanges LTE signaling and first bit rate data with UE  401  over eNodeB  411 . MME  420  also exchanges SIP signaling with IMS  430  and establishes an IMS bearer using PCRF  421 , such as a QCI  5 . In this example, UE  401  again initiates a ViLTE call with a destination UE over the LTE network and IMs  430 . In response to UE  401  initiating the ViLTE call, IMS  430  establishes a ViLTE media session over eNodeB  411  since eNodeB is capable of establishing the ViLTE media session. In a next operation, UE  401  is handed-over from eNodeB  411  to picocell  410 . 
     In response to identifying that UE  401  has been handed over from eNodeB  411  to picocell  410 , MME  420  determines that picocell  410  does not have Carrier Aggregation capabilities and that picocell  410  is not capable of providing the service level required for the initiated ViLTE call. MME  420  then notifies PCRF  421  of the difference in access technology between eNodeB  411  and picocell  410  using a trigger and PCRF  421  notifies IMS  430  to determine if the media session service level should be modified. In this example, it is determined that the service level should be modified. In response to determining that the service level should be modified, MME  420  then exchanges modification data with IMS  430  over a Diameter Application Protocol messaging. MME  420  then exchanges second modified codec data with UE  401  over eNodeB  411  using NAS messaging and IMS  430  transfers a notification to the Media Application Server indicating that the media session service level has been modified for UE  401 . In a final operation, a VoLTE media session is established between UE  401  and the destination UE over eNodeB  411 . 
       FIG. 7  illustrates MME  700  to manage a service level for an IMS media session for a UE. MME  700  is an example of MME  120  and MME  420 , although MME  120  and MME  420  may use alternative configurations and operations. MME  700  includes communication interface  701  and data processing system  702 . Data processing system  702  is linked to communication interface  701 . 
     Communication interface  701  comprises communication components, such as antennas, ports, amplifiers, filters, modulators, signal processors, and the like. Communication interface  701  exchanges first control data and second control data with a UE. Communication interface  701  also exchanges modification data with an IMS. 
     Data processing system  702  includes processing circuitry  703  and storage system  704  that stores software  705 . Processing circuitry  703  comprises a microprocessor and other circuitry that retrieves and executes software  705  from storage system  704 . Storage system  704  comprises a non-transitory storage medium, such as a disk drive, flash drive, data storage circuitry, or some other memory apparatus. Software  705  comprises computer programs, firmware, or some other form of machine-readable processing instructions. Software  705  may further include an operating system, utilities, drivers, network interfaces, applications, or some other type of software. When executed by processing circuitry  703 , software  705  directs processing system  702  to operate MME  700  as described herein. 
     In particular, when executed by processing circuitry  703 , UE attach module  706  directs processing circuitry  704  to drive communication interface  701  to exchange first control data with the UE to establish an IMS signaling bearer and a media session bearer. When executed by processing circuitry  703 , UE hand-over module  707  directs processing circuitry  703  to identify a UE hand-over between LTE access nodes during the IMS media session and determine an access technology difference between the LTE access nodes. 
     When executed by processing circuitry  703 , IMS service modification module  708  directs processing circuitry  703  to determine when the service level for the IMS media session should be modified based on the access technology difference. When executed by processing circuitry  703 , service modification module  708  directs processing circuitry  703  to drive communication interface  701  to exchange service modification data with the IMS. When executed by processing circuitry  703 , UE service modification module  709  also directs processing circuitry  704  to drive communication interface  701  to exchange second control data with the UE to indicate a modification to the service level for the IMS media session. 
     Referring back to  FIG. 1 , UE  101  includes a user interface, memory device, software, processing circuitry, Radio Frequency (RF) communication circuitry, or some other communication components. UE  101  may be a telephone, computer, e-book, mobile Internet appliance, wireless network interface card, media player, game console, or some other wireless communication apparatus—including combinations thereof. UE  101  is a dual mode device capable of communicating over multiple wireless protocols, including LTE wireless networks and non-LTE wireless networks. 
     LTE access nodes  110 - 111  may be eNodeBs, femtocells, picocells, repeaters, mini-macrocells, or some other type of wireless access points. LTE access nodes  110 - 111  comprise computers, bus interfaces, and communication ports that comprise processing circuitry and memory devices to store and execute various software modules. LTE access nodes  110 - 111  may also include other components such as a router, server, data storage system, and power supply. 
     MME  120  includes a computer, bus interface, and communication ports that have processing circuitry and memory to store and execute various software modules. MME  120  may also include other components such as a router, server, data storage system, and power supply. MME  120  may reside in a single device or may be distributed across multiple devices. 
     Wireless links  150 - 151  may use air, space, or some other wireless material that transports media. Wireless links  150 - 151  may use protocols, such as LTE, CDMA, EVDO, IP, or some other wireless communication formats—including combinations thereof. Communication links  152 - 155  may use metal, glass, optics, air, space, or some other material as the transport media. Communication links  152 - 155  may use Time Division Multiplexing (TDM), IP, Ethernet, Synchronous Optical Networking (SONET), communication signaling, wireless communications, or some other communication format—including improvements thereof. Communication links  152 - 155  may be a direct link, or can include intermediate networks, systems, or devices, and can include a logical network link transported over multiple physical links. 
     The above descriptions and associated figures depict specific embodiments to teach those skilled in the art how to make and use the best mode of the invention. The following claims specify the scope of the invention. Note that some aspects of the best mode may not fall within the scope of the invention as specified by the claims. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention and that the features described above can be combined in various ways to form multiple embodiments. As a result, the invention is not limited to the specific embodiments described above, but only by the claims and their equivalents.