Systems and methods for signal brokering in distributed evolved packet core (EPC) network architectures

Internet protocol (IP) address allocations in distributed EPC networks can be published to an IP address registry maintained at the central EPC entity in order to facilitate the routing of authentication authorization, and accounting (AAA) signaling of third party networks throughout the distributed EPC network architecture. The address allocations can be published directly to an address registry maintained by the central EPC entity, or indirectly via a cloud management server. Additionally, latencies associated with UE authentication in distributed EPC network architectures can be mitigated by triggering communication of the authentication or authorization profile upon reception of an update location request (ULR) message at the central EPC network entity.

TECHNICAL FIELD

The present invention relates generally to telecommunications, and, in particular embodiments, to systems and methods for signal brokering in distributed evolved packet core (EPC) Network architectures.

BACKGROUND

Conventional Long Term Evolution (LTE) and Evolved Packet System (EPS) architectures utilize centralized evolved packet core (EPC) networks to anchor internet protocol (IP) sessions of the user equipments (UEs). Next generation LTE and EPS architectures will likely employ distributed EPC networks due to the increased deployment of small cells, heterogeneous networks (het-nets), machine to machine (M2M) networks, and networks of devices. Distributed EPC network architectures typically include multiple distributed EPC entities comprising gateways, as well as a centralized EPC entity that serves as an intermediary between the distributed EPC entities and external third party networks.

SUMMARY OF THE INVENTION

Technical advantages are generally achieved, by embodiments of this disclosure which describe distributed signaling brokering agents for distributed evolved packet core (EPC) networks.

In accordance with an embodiment, a method for reserving resources in distributed evolved packet core (EPC) networks is provided. In this example, the method includes receiving an authentication, authorization, and accounting (AAA) protocol request from an application server at a brokering agent in a central EPC network. The AAA protocol request specifies an internet protocol (IP) address of a user equipment (UE) as a destination address of the AAA protocol request. The method further includes searching an address registry in accordance with the IP address to determine that the IP address is associated with a first one of a plurality of distributed EPC networks, and forwarding the AAA protocol request to a distributed policy and charging rules function (PCRF) entity in the first distributed EPC network. An apparatus for performing this method is also provided.

In accordance with another embodiment, a method for fast authentication in distributed evolved packet core (EPC) networks is provided. In this example, the method includes receiving an update location request/update location answer (ULR/ULA) message from a mobility management entity (MME) in a distributed EPC network at a brokering agent in a central EPC network. The ULR/ULA message specifies an international mobile subscriber identity (IMSI) of a user equipment (UE). The method further includes triggering communication of an authentication or authorization profile associated with the IMSI to a policy and charging rules function (PCRF) entity in the distributed EPC network in response to receiving the ULR/ULA message from the MME. The authentication or authorization profile is sent to the PCRF entity without receiving a corresponding profile request from the PCRF entity. An apparatus for performing this method is also provided.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of embodiments of this disclosure are discussed in detail below. It should be appreciated, however, that the concepts disclosed herein can be embodied in a wide variety of specific contexts, and that the specific embodiments discussed herein are merely illustrative and do not serve to limit the scope of the claims. Further, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of this disclosure as defined by the appended claims.

In EPC networks, a policy and charging rules function (PCRF) entity is responsible for making real-time policy decisions as well as accessing/maintaining subscriber databases. In centralized EPC networks, the PCRF entity maintains a central address registry that tracks IP address assignments of the gateway. The central address registry is used to route signaling received from third party networks. For example, a gateway in the central EPC network may dynamically assign an IP address to a user equipment (UE) when setting up the radio bearer. The PCRF entity in the central EPC network may then associate the IP address assignment with the RAN, which allows authentication, authorization, and accounting (AAA) requests received from third party networks to be appropriately routed to the RAN by mapping IP address carried by the AAA requests to the address registry.

One key distinction between centralized and the distributed EPC network architecture discussed herein is that this distributed EPC network architecture positions the PCRF entities and gateways at distributed EPC network locations. Traditionally, the distributed PCRF entities maintain local address registries that reflect IP address assignments made by the distributed gateways in their corresponding distributed EPC network locations. However, the local address registries in conventional distributed EPC networks do not track IP address assignments made by distributed gateways in other distributed EPC network locations, and are also not generally available to the central EPC entity. Accordingly, the central EPC entity may be unable to determine which distributed PCRF entity is associated with a destination IP address of incoming AAA requests, which makes the routing of said requests difficult (if not impossible)

Aspects of this disclosure provide techniques that publish IP address allocations in distributed EPC networks to an IP address registry maintained at the central EPC entity, which is then used to route AAA requests received from third party networks to the appropriate distributed EPC network. In an embodiment, the publication is triggered by an IP range allocation/re-allocation that allocates/reallocates ranges of IP addresses amongst distributed gateways in the distributed EPC networks. The ranges of IP address correspond to pools of address available for assignment by the corresponding distributed gateways. For example, a distributed gateway assigns addresses from that pool to a newly attached UE during link setup. In some embodiments, the address allocations are published directly to an address registry maintained by the central EPC entity. In other embodiments, the address allocations are first published to an address registry in a cloud management server, which updates the address registry at the central EPC entity.

Another potential issue in distributed EPC network architectures is that distribution of the PCRF entities adds latency to UE authentication, thereby delaying link setup. More specifically, link setup procedures usually include UE authentication at the EPC using an authentication or authorization profile stored at a subscription profile repository (SPR). In distributed EPC networks architectures, the subscription profile repository (SPR) is maintained at the central EPC network entity, and the authentication profiles are communicated from the central EPC network entity to the distributed PCRF entities upon request, e.g., upon the central EPC network entity receiving a corresponding profile request specifying the International Mobile Subscriber Identity (IMSI) of the UE. In conventional distributed EPC architectures, the profile request is communicated separately from (and after) the update location request (ULR) message, which is the message that initializes the link set-up. The time lapse between communication of the ULR and profile request messages adds latency to the UE authentication procedure, thereby delaying link setup in distributed EPC networks. Aspects of this disclosure avoid this latency by triggering communication of the authentication or authorization profile upon reception of the URL message at the central EPC network entity. These and other features are described in greater detail below.

FIG. 1illustrates a network100for communicating data. The network100comprises a base station110having a coverage area101, a plurality of mobile devices120, and a backhaul network130. As shown, the base station110establishes uplink (dashed line) and/or downlink (dotted line) connections with the mobile devices120, which serve to carry data from the mobile devices120to the base station110and vice-versa. Data carried over the uplink/downlink connections may include data communicated between the mobile devices120, as well as data communicated to/from a remote-end (not shown) by way of the backhaul network130. As used herein, the term “base station” refers to any component (or collection of components) configured to provide wireless access to a network, such as an enhanced base station (eNB), a macro-cell, a femtocell, a Wi-Fi access point (AP), or other wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., long term evolution (LTE), LTE advanced (LTE-A), High Speed Packet Access (HSPA), Wi-Fi 802.11a/b/g/n/ac, etc. As used herein, the term “mobile device” refers to any component (or collection of components) capable of establishing a wireless connection with a base station, such as a user equipment (UE), a mobile station (STA), and other wirelessly enabled devices. In some embodiments, the network100may comprise various other wireless devices, such as relays, low power nodes, etc.

FIG. 2illustrates a conventional centralized EPC network architecture200in which a gateway234and PCRF entity232in a central EPC network230serve as intermediaries between a third party network290and access points212,214in radio access networks (RANs). As shown, a GX interface extends between the PCRF entity232and the gateway234, and an S1-U interface extends between the gateway234and the access points212,214in the RAN. The S1-U and GX interfaces may correspond to backhaul network. During link setup, radio interfaces (solid arrows) are established between the access points212,214and the user equipments202,204, at which time the gateway234dynamically assigns IP addresses to the user equipments202,204. The PCRF entity232may maintain an address registry238that tracks the IP address assignments of the gateway234, and associates specific IP addresses (or address ranges) with specific RANs and/or access points.

After link setup, the user equipment204may attempt to access a service provided by the application server292by sending an SIP invite message to the application server292. The SIP message may include the IP address assigned to the UE204by the gateway234, and may prompt the application server292to send a AAA request to the PCRF entity232over an Rx interface in order to authenticate/authorize the user equipment204. The AAA request may specify the IP address carried by the SIP message as a destination address of the AAA request, and may be routed to the access point214via the gateway234in accordance with the address registry238.

The routing of AAA requests may be difficult in conventional distributed EPC network architectures, as the address registries are maintained in the distributed EPC networks, rather than at centralized EPC network entity.FIG. 3illustrates a conventional distributed EPC network architecture300in which distributed gateways334,344and distributed PCRF entities332,334in distributed EPC networks330,340serve as intermediaries between a third party network390and access points312,314,316in the RAN(s). As shown, Rx interfaces extend between an application server392in the third party network390and a central EPC entity350, as well as between the central EPC entity and the distributed PCRF entities332,342in the distributed EPC networks330,340. The distributed PCRF entities332,342and the distributed gateways334,344may behave similar to the PCRF234and the gateway232in that the distributed gateways334,344may assign IP addresses to the UEs302,304accessing their respective RANs, and the distributed PCRF entities332,342may maintain address registries338,348tracking those IP address assignments.

However, the address registries338,348in the conventional distributed EPC network architecture300are locally maintained such that the address registry338does not reflect IP address assignments of the distributed gateway344, and the address registry348does not reflect IP address assignments of the distributed gateway334. Moreover, in the conventional distributed EPC network architecture300, IP address allocation information is not available to the central EPC entity350. As a result, the central EPC entity350may be unable to determine which distributed EPC network340to route AAA requests (or other signaling) received from the third party network390.

Aspects of this disclosure provide techniques that publish IP address assignments of distributed EPC networks to an IP address registry that is available to the central EPC entity, thereby allowing the central EPC entity to appropriately route AAA requests received from third party networks.FIG. 4illustrates an embodiment distributed EPC network architecture400in which IP address assignments of distributed gateways434,444are published into an address registry458in available to a central EPC entity450. In one example, an IP address re-allocation occurs in which a range of IP addresses are allocated to the distributed gateway444. This prompts the distributed PCRF entity442to initiate a publication to one or both of the address registries458,468. In one example, the distributed PCRF entity442directly publishes the address range allocation to the address registry458in the central EPC entity450. In another example, the distributed PCRF entity442publishes the address range allocation to the address registry468in the cloud management entity450, and the cloud management entity450subsequently updates the address registry458in the central EPC entity450. At a later point in time, the UE404initiates establishment of a radio connection with an access point416, prompting the distributed gateway444to assign an IP address from the pool of allocated addresses to the UE404. Thereafter, the UE404attempts to access a service provided by the application server by sending an SIP request message to the third party network490. The SIP request message carries the IP address assigned to the UE404, and prompts the third party network490to send a AAA request to the central EPC network entity450. The AAA request is adapted to elicit an authentication and/or authorization of the UE404, and specifies the IP address assigned to the UE404as a destination address of the AAA request. The central EPC entity450references the address registry458to identify that the IP address specified by the AAA request is allocated to the distributed gateway444in the distributed EPC network440, and, as a result, the central entity450forwards the AAA request to the distributed PCRF entity442in the distributed EPC network440. The AAA request is then relayed to the UE404. In some embodiments, the CMBA456and the DMBAs436,446seamlessly relay the AAA requests between the central EPC network entity450and the distributed EPC networks430,440.

FIG. 5illustrates a communications sequence500for address registry publishing and AAA routing in the embodiment distributed EPC network architecture400. As shown, the communications sequence500begins with an address re-allocation procedure510, in which an IP address range is allocated to the gateway444. Address reallocation may allocate a range of addresses to a gateway for dynamic assignment. Thereafter, the address re-allocation510is published520to the address registry458available to the central EPC entity450. The publication may be directly communicated from the PCRF entity432to the CMBA456. Conversely, the publication may be indirectly communicated from the PCRF entity432to the cloud management server460, and then from the could management server460to the CMBA456. Thereafter, the UE404and access point414engage in a link setup530, during which time the distributed gateway444performs an IP address assignment540to assign a specific IP address (IP-N) to the UE404. Notably, the specific IP address (IP-N) is within the range of IP addresses allocated to the gateway444during the address re-allocation procedure510. Next, the UE404sends an SIP request550to the third party network490to request a service provided by the application server492. The SIP request550specifies the IP-N as a source address of the SIP request550, and prompts the third party network490to send a AAA request560specifying the IP-N as a destination address of the AAA request560to the central entity450for the purpose of authenticating the UE404.

The central EPC entity450will then reference the address registry458to determine that the IP-N is associated with the distributed EPC network440(or the distributed PCRF entity442), and forward the AAA request560to the distributed PCRF entity442. In some embodiments, the forwarding of the AAA request560may be facilitated by the CMBA456and the DMBA446, which may be transparent to the third party network490and/or other participating entities/components. The AAA request560is then forwarded from the distributed PCRF to the UE404via the distributed gateway444and the access point414.

FIG. 6illustrates a method600for routing AAA signaling between a third party network and distributed PCRF entities in distributed ECP networks, as may be performed by a central EPC network entity (e.g., a distribute message broker agent). As shown, the method600begins at step610, where the central EPC network entity receives a AAA request from a third party network. The AAA request specifies a destination IP address of the AAA request. Subsequently, the method600proceeds to step620, where the central EPC network entity searches an address registry to identify the distributed PPCRF entity associated with the IP address carried by the AAA request. Next, the method600proceeds to step630, where the central EPC network entity forwards the AAA request to the distributed PCRF entity.

Another potential issue with distributed EPC network architectures is the latency in providing an authentication or authorization profile to the distributed PCRF during link setup. More specifically, the authentication or authorization profile is typically stored in a Subscription profile repository (SPR) maintained by the central EPC network entity, and is communicated to the distributed PCRF entity to allow the distributed EPC network to authenticate the UE. Generally speaking, UE authentication is required to be performed during link setup, and therefore latency in communicating the authentication or authorization profile may delay link setup.

In conventional networks, the SPR communicates the authentication or authorization profile to the distributed PCRF only after receiving a corresponding profile request message from the distributed PCRF. The profile request message specifies the International Mobile Subscriber Identity (IMSI) of the UE, and is traditionally communicated separately from (and after) the update location request (ULR) message. Thus, the time between communication of the ULR and profile request messages adds latency to authentication of the UE in distributed EPC networks, thereby delaying link setup.

Aspects of this disclosure avoid this latency by triggering communication of the authentication or authorization profile based on the URL message.FIG. 7illustrates an embodiment distributed EPC network architecture700in which an authentication or authorization profile is triggered by a ULR message. As shown, the UE702connects to the AP712, which prompts an MME in the distributed EPC network730to send an update location request (ULR) or update location answer (ULA) message to the central EPC network750. The ULR/ULA message triggers communication of the authentication profile message from the central EPC network750to the distributed EPC network730without a profile request message being communicated from the distributed EPC network730to the central EPC network730. In some embodiments, this is facilitated by a DMBA in the central EPC network730, which submits a request to the SPR upon receiving the ULR message.

Notably, the DMBA can broker and cache subscriber information seamlessly. When a user attaches to the network, S6a signaling between the mobility management entity (MME) and HSS (steps 1, 2) is brokered via the DMBA. The DMBA subscribes to the UE's profile (step 3). The SPR notifies the DMBA with the UE profile (step 4) and the DMBA delivers this UE profile to PCRF (steps 5, 6). If there is any update in the UE profile, the SPR notifies the DMBA and steps 4, 5, 6 are repeated until the session terminates.

FIG. 8illustrates a method800for triggering communication of the authentication or authorization profile based on the URL message, as may be performed by a central EPC network entity (e.g., a distribute message broker agent). As shown, the method800begins at step810, where the central EPC network entity receives a ULR/ULA message from a distributed EPC network entity, e.g., an MME in a distributed EPC network. Subsequently, the method800proceeds to step820, where the central EPC network entity triggers communication of an authentication profile message to the distributed EPC network by virtue of receiving the ULR message, and without receiving a separate profile request message from the distributed EPC network.

FIG. 9illustrates a distributed EPC architecture, where functionality for handling sessions is hosted on virtual machines (VMs) in the distributed EPC. Other functions such as home subscriber service (HSS) and subscription profile repository (SPR) are located in a central cloud/data center (DC). Due to such a distribution, session handling is optimal for many cases. However, some signaling needs further mechanisms to operate seamlessly.

An embodiment enhances existing distributed EPC mechanisms and includes brokering and caching of authentication, authorization, and accounting (AAA) protocol (e.g., Diameter) messages and subscriber information.

FIG. 10illustrates an embodiment signaling broker distributed message brokering agent (DMBA). The DMBA brokers AAA, e.g., Diameter requests from various distributed EPC entities to the servers (online charging system (OCS), CDG, HSS, etc.) in the central DC.

An embodiment DMBA manages security associations similar to a Diameter edge agent (DEA) and supports mechanisms for handling requests from an external network (application server (AS)→Rx→PCRF). In these cases, the DMBA locates the right PCRF that is serving the UE. The DMBA also is used to optimize the download of a user profile to PCRF, OCS when the user attaches to the network.

FIG. 11illustrates PCRF discovery in a distributed EPC architecture. When a UE obtains service from a third party network (TPN) that has a quality of service (QoS)/service level agreement (SLA) relationship with the UE's operator, the TPN server (AS) may request for QoS for the flow. The extensions to support this in a distributed EPC are described below.

The cloud management entities—in this case the resource registry—of the distributed locations sync up on resources including Internet protocol (IP) address/prefix range associated with packet gateway (PGW) access point name (APN)/address assignments. The DMBA in each location subscribes to information on IP address ranges, associated PCRF as shown inFIG. 3.

When an Rx interface request (e.g., AA Request) from an AS arrives, the DMBA consults its table and maps the IP address/prefix in the request to the information of distributed EPC locations. The DMBA then proxies the request to the right PCRF (PCRF1 inFIG. 3).

FIG. 12illustrates OCS in a distributed EPC to optimize dynamic charging. Similar to the mechanism for PCRF, the DMBA can download the user profile to OCS. If the subscription profile for DMBA includes an online charging parameter/flag, the DMBA downloads the UE profile to OCS (steps 4, 5, 6). If there is any update in the UE profile, the SPR notifies the DMBA and steps 4, 5, 6 are repeated until the session terminates.

An embodiment distributed signaling brokering agent allows the various distributed functions to discover and message seamlessly. An embodiment mechanism for the brokering agent routes requests from outside the operator network (e.g., AS, PCRF and Rx signaling). An embodiment mechanism optimizes the download of the subscriber profile to the distributed PCRF and OCS entities. Embodiments may be implemented in packet core networks and devices, such as 3GPP evolved packet core networks and devices, and the like.

FIG. 13is a block diagram of a processing system that may be used for implementing the devices and methods disclosed herein. Specific devices may utilize all of the components shown, or only a subset of the components, and levels of integration may vary from device to device. Furthermore, a device may contain multiple instances of a component, such as multiple processing units, processors, memories, transmitters, receivers, etc. The processing system may comprise a processing unit equipped with one or more input/output devices, such as a speaker, microphone, mouse, touchscreen, keypad, keyboard, printer, display, and the like. The processing unit may include a central processing unit (CPU), memory, a mass storage device, a video adapter, and an I/O interface connected to a bus.

The bus may be one or more of any type of several bus architectures including a memory bus or memory controller, a peripheral bus, video bus, or the like. The CPU may comprise any type of electronic data processor. The memory may comprise any type of system memory such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), a combination thereof, or the like. In an embodiment, the memory may include ROM for use at boot-up, and DRAM for program and data storage for use while executing programs.

The mass storage device may comprise any type of storage device configured to store data, programs, and other information and to make the data, programs, and other information accessible via the bus. The mass storage device may comprise, for example, one or more of a solid state drive, hard disk drive, a magnetic disk drive, an optical disk drive, or the like.

The video adapter and the I/O interface provide interfaces to couple external input and output devices to the processing unit. As illustrated, examples of input and output devices include the display coupled to the video adapter and the mouse/keyboard/printer coupled to the I/O interface. Other devices may be coupled to the processing unit, and additional or fewer interface cards may be utilized. For example, a serial interface such as Universal Serial Bus (USB) (not shown) may be used to provide an interface for a printer.

The processing unit also includes one or more network interfaces, which may comprise wired links, such as an Ethernet cable or the like, and/or wireless links to access nodes or different networks. The network interface allows the processing unit to communicate with remote units via the networks. For example, the network interface may provide wireless communication via one or more transmitters/transmit antennas and one or more receivers/receive antennas. In an embodiment, the processing unit is coupled to a local-area network or a wide-area network for data processing and communications with remote devices, such as other processing units, the Internet, remote storage facilities, or the like.

The following references are related to subject matter of the present application. Each of these references is incorporated herein by reference in its entirety:3GPP TS 23.401 version 12.2.0, 3rd Generation Partnership Project, Technical Specification Group Services and System Aspects, General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access (Release 12) (September, 2013).