PATENT DOCUMENT

Publication Number: US-10638449-B2
Application Number: US-201414771859-A
Country: US
Kind Code: B2

Title: Systems and methods using a centralized node to collect ran user plane congestion information

Abstract:
A centralized node collects and stores radio access network (RAN) user plane congestion information (RCI) that is reported from the RAN to a core network. The centralized node provides a congestion information collection function (CICF) and includes one or more interface to communicate with a mobility management entity (MME) and/or a serving general packet radio service (GPRS) support node (SGSN). The MME and/or SGSN allows the centralized node to determine user equipments (UEs) and associated access point name (APNs) impacted by RAN congestion. The centralized node reports the RCI to a policy and charging rules function (PCRF) associated with the APNs for congestion mitigation.

Claims:
The invention claimed is: 
     
       1. A radio access network (RAN) congestion awareness function (RCAF) element, the RCAF element comprising:
 a first interface between the RCAF element and an operations and maintenance (O&amp;M) system to receive RAN user plane congestion information (RUCI) from the O&amp;M system, the RCAF element to process the RUCI to determine a congestion level of a base station or a cell; 
 a second interface between the RCAF element and a mobility management entity (MME) to request and receive a list of international mobile subscriber identities (IMSIs) served by the base station or cell, and to receive, in response to the request for the list of IMSIs, a corresponding list of access point names (APNs) of active packet data network (PDN) connections from the MME; and 
 a third interface between the RCAF element and a policy and charging rules function (PCRF) serving the PDN connection for congestion mitigation to report the RUCI to the PCRF, wherein the PCRF is identified from a plurality of PCRFs using the list of APNs, wherein the RCAF element uses the RUCI from the first interface to determine a congested base station or congested cell, uses the list of IMIs from the second interface to determine a user equipment (UE) served by the congested base station or congested cell, and uses the third interface to report the RUCI to the PCRF associated with the list of APNs from the second interface. 
 
     
     
       2. The RCAF element of  claim 1 , wherein the RCAF element is configured to receive a UE identifier, wherein the UE identifier comprises an international mobile subscriber identity (IMSI) corresponding to the UE served by the base station or cell. 
     
     
       3. The RCAF element of  claim 1 , wherein the RUCI includes one or more information element (IE) selected from a group comprising a first IE for a congested interface direction and node, a second IE for a congestion severity level, a third IE for a congestion situation indicating a change in whether or not congestion is detected, a fourth IE for congestion cell location information, a fifth IE for identifying the UE, a sixth IE for identifying a user associated with the UE, a seventh IE for identifying an APN from the list of APNs, an eighth IE for packet data protocol (PDP) context information, and a ninth IE for a bearer identifier. 
     
     
       4. The RCAF element of  claim 3 , wherein the first IE for the congested interface direction and node includes at least one interface or node identifier selected from a group comprising a radio interface downlink identifier, a radio interface uplink identifier, a network interface downlink identifier, a network interface uplink identifier, a RAN node identifier. 
     
     
       5. The RCAF element of  claim 3 , wherein the fifth IE for identifying the UE comprises an international mobile equipment identity (IMEI), and wherein the sixth IE for identifying a user associated with the UE comprises an international mobile subscriber identity (IMSI). 
     
     
       6. The RCAF element of  claim 1 , further comprising:
 a memory device to store the RUCI received through the first interface; and 
 a processor to process the stored RUCI and to trigger the PCRF to modify an internet protocol connectivity access network (IP-CAN) session. 
 
     
     
       7. A method for user plane congestion awareness in a mobile network, the method comprising:
 receiving and storing an event or report indicating a change in a radio node or cell user plane congestion status with an radio access network (RAN) congestion awareness function (RCAF) element from an operations and maintenance (O&amp;M) system, the event or report including an indication of one or more congested areas and corresponding congestion levels; 
 determining one or more mobility management entities (MMES) associated with the one or more congested areas; 
 establishing an interface between the one or more MMES and the RCAF element; 
 determining, through the interface, wireless communication devices and associated active connections in the one or more congested areas, wherein determining the wireless communication devices comprises:
 querying, via the interface, for the wireless communication devices; 
 receiving, via the interface, a list of international mobile subscriber identities (IMSIs) associated with the wireless communication devices; and 
 receiving, via the interface, a list of access point names (APNs) of the associated active connections corresponding the list of IMSIs; 
 
 identifying one or more network elements from a plurality of network elements configured to adjust a quality of service (QoS), the one or more identified network elements configured to adjust QoS for the one or more congested areas, respectively, wherein the one or more network elements configured to adjust QoS for the one or more congested areas are identified using the list of APNs, wherein the one or more elements comprise respective policy and charging rules function (PCRF) nodes; and 
 communicating, using the RCAF element, user plane congestion information to the one or more identified network elements serving the wireless communication devices. 
 
     
     
       8. The method of  claim 7 , wherein receiving and storing the event or report comprises:
 receiving the event or report from a radio access network (RAN); and 
 storing the event or report for a predetermined period of time. 
 
     
     
       9. The method of  claim 8 , further comprising sending a request to the RAN for the event or report based on a configured time interval. 
     
     
       10. The method of  claim 7 , wherein receiving and storing the event or report comprises receiving the event or report from one or more network elements selected from a group comprising the O&amp;M system, a access network discovery and selection function (ANDSF) server, a mobility management entity (MME), a serving gateway (S-GW), serving gateway general packet radio service (GPRS) support node (SGSN), a gateway GPRS support node (GGSN), and a packet data network (PDN) gateway (P-GW). 
     
     
       11. The method of  claim 7 , wherein determining the one or more MMES associated with the one or more congested areas comprises:
 determining tracking area identities (TAIs) based fully qualified domain name (FQDN) for MME discovery; and 
 receiving, from the O&amp;M system of a radio access network (RAN), a list of the TAIs supported by the one or more congested areas. 
 
     
     
       12. A server comprising:
 a processor; 
 a storage device to store an indication from an operations and maintenance (O&amp;M) system that demand for radio access network resources exceeds available capacity in an identified area of a wireless cellular network; 
 a radio access network (RAN) congestion awareness function (RCAF) comprising instructions that, when executed by the processor, manage congestion information for the wireless cellular network, the RCAF configured to:
 establish a first interface between an RCAF element and the O&amp;M system; 
 discover a mobility management entity (MME) serving the identified area of the wireless cellular network; 
 establish a second interface between the MME and the RCAF element; 
 request and receive, from the MME, a list of international mobile subscriber identities (IMSIs) associated with the identified area of the wireless cellular network; 
 receive, from the MME in response to the request for the list of IMSIs, a corresponding list of access point names (APNs) of active packet data network (PDN) connections; 
 discover a network node associated with the list of IMSIs from a plurality of network nodes configured to initiate an internet protocol connectivity access network (IP-CAN) session modification procedure; 
 establish a third interface between the RCAF element and the network node; and 
 notify the network node configured to initiate the IP-CAN session modification procedure of the demand for radio access network resources. 
 
 
     
     
       13. The server of  claim 12 , wherein the RCAF is further configured to:
 receive, from the O&amp;M system, the indication that demand for radio access network resources exceeds available capacity. 
 
     
     
       14. The server of  claim 13 , wherein the RCAF is further configured to:
 receive, from the O&amp;M system, tracking area identity (TAI) supported by the identified area of the wireless cellular network; and 
 use the TAI to discover the MME. 
 
     
     
       15. The server of  claim 12 , wherein the discovered network node associated with the list of IMSIs comprises a policy and charging rules function (PCRF) associated with the corresponding list of APNs. 
     
     
       16. The server of  claim 12 , wherein the RCAF is further configured to:
 receive the indication that demand for radio access network resources exceeds available capacity through one or more interface selected from a group comprising a user plane interface, a control plane interface, and a network management plane interface. 
 
     
     
       17. A computer program product comprising a non-transitory computer-readable storage medium storing program code for causing one or more processors to perform a method, the method comprising:
 storing an indication that demand for radio access network resources exceeds available capacity from an operations and maintenance (O&amp;M) system in an identified area of a wireless cellular network; and 
 performing a radio access network (RAN) congestion awareness function (RCAF) comprising:
 establishing a first interface between an RCAF element and the O&amp;M system; 
 receiving the indication that demand for radio access network resources exceeds available capacity; 
 receiving tracking area identity (TAI) supported by the identified area of the wireless cellular network; 
 discovering, using the TAI, a mobility management entity (MME) serving the identified area of the wireless cellular network; 
 establishing a second interface between the MME and the RCAF element; 
 requesting and receiving, from the MME, a list of international mobile subscriber identities (IMSIs) associated with the identified area of the wireless cellular network; 
 discovering a network node associated with the list of IMSIs from a plurality of network nodes configured to initiate an internet protocol connectivity access network (IP-CAN) session modification procedure; 
 establishing a third interface between the RCAF element and the network node; and 
 notifying the network node configured to initiate the IP-CAN session modification procedure of the demand for radio access network resources. 
 
 
     
     
       18. The computer program product of  claim 17 , wherein performing the RCAF further comprises receiving, from the MME in response to the request for the list of IMSIs, a corresponding list of access point names (APNs) of active packet data network (PDN) connections. 
     
     
       19. The computer program product of  claim 18 , wherein the discovered network node associated with the list of IMSIs comprises a policy and charging rules function (PCRF) associated with the APNs. 
     
     
       20. The computer program product of  claim 17 , wherein performing the RCAF further comprises receiving the indication that demand for radio access network resources exceeds available capacity through one or more interface selected from a group comprising a user plane interface, a control plane interface, and a network management plane interface. 
     
     
       21. A computer program product comprising a non-transitory computer-readable storage medium storing program code for causing one or more processors to perform a method, the method comprising:
 receiving, via a first interface between a radio access network (RAN) congestion awareness function (RCAF) element and the an operations and maintenance (O&amp;M) system, radio access network (RAN) user plane congestion information (RUCI) from the O&amp;M system; 
 processing the RUCI to determine a congestion level of a base station or a cell; 
 determining a mobility management entity (MME) serving an identified area of a wireless cellular network; 
 requesting and receiving a list of user equipment (UE) identifiers for UEs served by the base station or the cell from the MME over a second interface between the RCAF element and the MME; 
 receiving, in response to the request for the list of UE identifiers, a list of access point names (APNs) of an active packet data network (PDN) connections corresponding to the list of UE identifiers from the MME over the second interface; 
 discovering a policy and charging rules function (PCRF) associated with the list of UE identifiers from a plurality of PCRFs; and 
 reporting the RUCI to the PCRF identified from the plurality of PCRFs as serving one of the PDN connections associated with the list of APNs for congestion mitigation over a third interface between the PCRF and the RCAF element. 
 
     
     
       22. The computer program product of  claim 21 , further comprising receiving a UE identifier, wherein the UE identifier comprises an international mobile subscriber identity (IMSI) corresponding to the UE served by the base station or the cell. 
     
     
       23. The computer program product of  claim 21 , wherein the RUCI includes one or more information element (IE) selected from a group comprising a first IE for a congested interface direction and node, a second IE for a congestion severity level, a third IE for a congestion situation indicating a change in whether or not congestion is detected, a fourth IE for congestion cell location information, a fifth IE for identifying a UE, a sixth IE for identifying a user associated with the UE, a seventh IE for identifying an APN, an eighth IE for packet data protocol (PDP) context information, and a ninth IE for an evolved packet system (EPS) bearer identifier. 
     
     
       24. The computer program product of  claim 23 , wherein the first IE for the congested interface direction and node includes at least one interface or node identifier selected from a group comprising a radio interface downlink identifier, a radio interface uplink identifier, a network interface downlink identifier, a network interface uplink identifier, a RAN node identifier. 
     
     
       25. The computer program product of  claim 23 , wherein the fifth IE for identifying the UE comprises an international mobile equipment identity (IMEI), and wherein the sixth IE for identifying a user associated with the UE comprises an international mobile subscriber identity (IMSI). 
     
     
       26. The computer program product of  claim 21 , wherein the method further comprises:
 storing the RUCI; and 
 processing the stored RUCI to trigger the PCRF to modify an internet protocol connectivity access network (IP-CAN) session.

Description:
RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 61/816,662, filed Apr. 26, 2013 which is hereby incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to wireless communication systems. More particularly, the present disclosure relates to radio access network user plane congestion awareness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating example radio access network (RAN) user plane congestion in a wireless communication system. 
         FIG. 2  is a block diagram of a non-roaming architecture including a centralized node according to one embodiment. 
         FIGS. 3A and 3B  are block diagrams of roaming architectures including centralized nodes according to certain embodiments. 
         FIG. 4  is a block diagram of another architecture including a centralized node according to one embodiment. 
         FIGS. 5A and 5B  illustrate example processes for reporting RAN user plane congestion information (RCI) via the control plane according to certain embodiments. 
         FIGS. 6A and 6B  illustrate example processes for reporting RCI via the user plane according to certain embodiments. 
         FIGS. 7A and 7B  illustrate example processes for reporting RCI using policy and charging control (PCC) according to certain embodiments. 
         FIGS. 8A, 8B, and 8C  illustrate example processes for reporting RCI via the network management plane according to certain embodiments. 
         FIGS. 9A and 9B  illustrate example processes for reporting RCI via the control plane according to certain embodiments. 
         FIGS. 10A and 10B  illustrate example processes for reporting RCI via the user plane according to certain embodiments. 
         FIGS. 11A and 11B  illustrate example processes for reporting RCI using PCC according to certain embodiments. 
         FIGS. 12A, 12B, and 12C  illustrate example processes for reporting RCI via the network management plane according to certain embodiments. 
         FIG. 13  illustrates an example process for managing RCI in a core network according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Wireless mobile communication technology uses various standards and protocols to transmit data between a base station and a wireless communication device. Wireless communication system standards and protocols can include, for example, the 3rd Generation Partnership Project (3GPP) long term evolution (LTE), global system for mobile communications (GSM), and enhanced data rates for GSM (EDGE) standards. In 3GPP radio access networks (RANs) in LTE systems, the base station can include Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node Bs (also commonly denoted as evolved Node Bs, enhanced Node Bs, eNodeBs, or eNBs) and/or Radio Network Controllers (RNCs) in an E-UTRAN, which communicate with a wireless communication device, known as user equipment (UE). 
     Mobile operators are seeing significant increases in user data traffic. For some operators, user data traffic has more than doubled annually for several years. Although the data capacity of networks has increased significantly, the observed increase in user traffic continues to outpace the growth in capacity. This is resulting in increased network congestion and in degraded user service experience. 
     RAN user plane congestion occurs when the demand for RAN resources exceeds the available RAN capacity to deliver the user data for a period of time. RAN user plane congestion leads, for example, to packet drops or delays, and may or may not result in degraded end-user experience. Short-duration traffic bursts are normal conditions at any traffic load level, and generally are not considered to be RAN user plane congestion. Likewise, a high-level of utilization of RAN resources (based on operator configuration) is generally considered a normal mode of operation and might not be RAN user plane congestion. Further, RAN user plane congestion includes user plane congestion that occurs over air interface (e.g., LTE-Uu interfaces), in the radio node (e.g., eNB), and/or over the back haul interface between the RAN and the core network (e.g., S1-u interface). 
     I. Overview of Ran User Plane Congestion Information 
       FIG. 1  is a block diagram illustrating example RAN user plane congestion in a 3GPP system  100 . The system  100  includes a first cell  110  served by a first eNodeB  112 , a second cell  114  served by a second eNodeB  116 , and a third cell  118  served by a third eNodeB  120 . The cells  110 ,  114 ,  118  communicate user data through a 3GPP RAN  122 , backhaul interface  124 , evolved packet core (EPC or “core network”)  126 , and the internet  128  or other network. In this example, the cells  110 ,  114 ,  118  each have a radio capacity of 75 Mbps and the backhaul interface  124  between the RAN  122  and the EPC  126  has a capacity of 100 Mbps. In one example scenario, user plane congestion occurs when the traffic volume exceeds the capacity of a cell. User plane congestion  129  occurs in the second cell  114 , for example, when UEs  130 ,  132  in the second cell  114  are generating user plane traffic totaling the cell capacity, and then an additional or an existing UE  134  attempts to generate additional user plane traffic. 
     By way of another example, user plane congestion  136  may also occur when the user plane data volume of the UEs  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142  being served by the cells  110 ,  114 ,  118  totals more than the actual capacity of the interface  124  between the RAN  122  and the EPC  126 . Such user plane congestion  136  may limit the performance of each of the UEs  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142  involved. This may lead to excessive data rate reduction or service denial. Even though each cell  110 ,  114 ,  118  may have the necessary capacity to support the respective UEs  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142  it is serving, the capacity of the backhaul interface  124  has an impact on each UE  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142  and may in the worst case actually prevent one or more of the UEs  130 ,  132 ,  134 ,  136 ,  138 ,  140 ,  142  from being offered any capacity at all. 
     Thus, in certain embodiments, the system  100  attempts to mitigate RAN user plane congestion to overcome or lessen the negative impact on the perceived service quality for data traffic. Congestion mitigation may include, for example, traffic prioritization, traffic reduction, and/or traffic limitation (e.g., throttling). Depending on an operator&#39;s mitigation policies, different congestion mitigation measures may be selected based on the user&#39;s subscription class, the type of application, and/or the type of content. To provide congestion mitigation, certain network elements outside the RAN  122  may need to become aware of the congestion status. 
     In certain embodiments disclosed herein, the RAN  122  (and/or one or more other network element) determines a congestion level using RAN measurements based on monitoring RAN resources. RAN user plane congestion information (RUCI or simply RCI) indicates the congestion level from the RAN  122  to the core network  126 . RCI may indicate the level of congestion by, for example, a scalar value. RCI may, in some embodiments, include other information such as the location of the congested RAN (e.g., the RCI may include a cell identifier (ID) corresponding the RAN  122  or a particular cell of the RAN  122 ). 
     In addition, or in other embodiments, the RCI may include one or more of the following information elements: a congested interface element indicating whether the congestion is in the radio interface (e.g., LTE-Uu, Uu) or in the network interface (e.g., Gb, Iu-PS, S1-U); a congestion severity level element including a predefined number indicating the level (e.g., 0 to 7, where a smaller value means more severe, or vice-versa); a congestion situation element that indicates whether there currently is congestion (e.g., a value of 0 indicates no congestion and a value of 1 indicates congestion); for cell-based user plane congestion notification, a cell ID element; for UE-based user plane congestion notification, a UE ID element; for APN-based user plane congestion notification, an access point name (APN) element; and/or for packet data protocol (PDP) context or evolved packet system (EPS) bearer based user plane congestion notification, a relative ID element. 
     In various embodiments, RCI can be transferred to the core network via the user plane (e.g., extending the GTP-U extension header), the control plane (e.g., S1-MME, S11, S5/S8, Gx, Rx interfaces, or other signaling interfaces), or the network management plane (e.g., the operations and maintenance (O&amp;M) system, the access network discovery and selection function (ANDSF), or other server or management plane element). Regardless of whether the RCI is transferred via the user plane, the control plane, or the network management plane, a policy and charging rules function (PCRF) within the core network may provide policies for congestion mitigation. However, core network elements, such as the gateway general packet radio service (GPRS) support node (GGSN) or the packet data network (PDN) gateway (P-GW), are not designed to store the RCI, which may be stateful. Further, in roaming cases, the number of eNodeBs that have indirect user plane or control plane interfaces may be very large. It may be very difficult for the GGSN or P-GW to store this large amount of information in addition to performing its regular routing functionality. 
     II. Centralized Node for Reporting RCI to the Core Network 
     In certain embodiments, a centralized node terminates RCI reporting from the RAN to the core network. The centralized node may be a logical function entity, and may be referred to herein as either a RAN congestion awareness function (RCAF) or a congestion information collection function (CICF). Regardless of whether the centralized node is referred to as RCAF or CICF, the centralized node uses the reported RCI to coordinate the rules so that the PCRF applies the same adjusted quality of service (QoS) on the same QoS class identifier (QCI) across different APNs using different P-GWs. As discussed below, the RCAF or CICF collects RCI, stores the RCI for a period of time, discovers the proper PCRF for an impacted UE, and queries for and receives a list of UEs and related APNs for each UE connected to a given eNodeB experiencing user plane congestion. The RCAF or CICF communicates with PCRFs serving the impacted UEs for RAN user plane congestion information reporting. 
     A. Example Architectures 
       FIG. 2  is a block diagram of a non-roaming architecture for E-UTRAN including a centralized node  210  according to one embodiment. In this example, and in other examples discussed herein, the centralized node  210  is referred to as CICF  210 . However, as discussed above, the term RCAF may also be applied to the centralized node  210 . The CICF  210  may be a standalone function or may be collocated with other network elements within a public land mobile network (PLMN)  200 . The PLMN  200  includes an interface S 101  between the CICF  210  and an eNodeB  212 , an interface S 102  between the CICF  210  and a mobility management entity (MME)  214 , an interface S 103  between the CICF  210  and a serving gateway (S-GW)  216 , an interface S 104  between the CICF  210  and a serving GPRS support node (SGSN)  218 , an interface S 105  between the CICF  210  and an O&amp;M system  220 , an interface S 106  between the CICF  210  and a P-GW  222 , and an interface S 107  between the CICF  210  and a PCRF  224 . The interfaces S 101 , S 102 , S 103 , S 104 , S 105 , S 106 , S 107  may also be referred to herein as references points. The eNodeB  212  is in wireless communication with one or more UEs  226 . The SGSN  218  may provide core network access to a GSM EDGE radio access network (GERAN)  228  and/or a UTRAN  230 . 
     The CICF  210  collects and stores RCI. Based on the stored RCI, according to certain embodiments, the CICF  210  triggers the PCRF  224  to modify an internet protocol connectivity access network (IP-CAN) session. The PCRF  224  may then provide policies for congestion mitigation. 
     In one embodiment, the CICF  210  collects raw user plane congestion information from the O&amp;M  220  through the interface S 105 . The O&amp;M  220  may correspond to operation support system (OSS) level features of the RAN operator (the O&amp;M  220  is not assumed to be within the eNodeB or RNC). The CICF  210  determines the list of UEs  226  impacted by the user plane congestion. The CICF  210  may also integrate the RAN congestion status with an integration time fitting with core mitigation tools (e.g., to provide the PCRF  224  only with information on sustained congestion). In addition, or in other embodiments, the CICF  210  also provides “spatial” integration of the RAN congestion information (due to mobility and to one of more of the UEs  226  possibly being served by multiple cells, the RCI associated with a cell may depend on the congestion status in the neighboring cells). 
     The CICF  210  sends the RCI over the interface S 107  between the CICF  210  and the PCRF  224 . Over the interface S 102 , the MME  214  provides the CICF  120  with a list of impacted UEs  226  (e.g., a list of international mobile subscriber identities (IMSIs) associated with the UEs  226 ) in a given eNodeB ID or E-UTRAN cell global identifier (ECGI). For each of the IMSIs in the list, the SGSN sends the APNs of the active PDN connections. The interface S 104  between the CICF  210  and the SGSN  218  is used, for a set of IMSIs, to provide the CICF  210  with the list of APNs of the active PDN connections of each of these IMSIs. In certain embodiments, no congestion information is sent over the interface S 102  or the interface S 104 . 
     In certain embodiments, the RCI is defined over the interface S 107  and includes congestion and/or abatement location information (e.g., eNodeB ID, cell ID, or 3G service area ID). The congestion location information may provide an indication of the congested interface direction and node including, for example, radio interface downlink information (e.g., LTE-Uu, Uu), radio interface uplink information, network interface downlink information (e.g., Gb, Iu-PS, S1-U), network interface uplink information, and/or RAN node information (e.g., eNodeB, RNC, and/or base station subsystem (BSS) information). 
     The RCI defined over the interface S 107  also includes congestion level information (e.g., a congestion severity level based on a scale of 0-7, or 0-10, or some other scale), and/or congestion situation information indicating the existence of congestion (e.g., a value of 0 indicating congestion disappears, and a value of 1 indicating congestion appears). The RCI may also include a validity time associated with the congestion information. When the validity time elapses and no further congestion information has been received, for example, the congestion is assumed to be over. In addition, or in other embodiments, the RCI includes a UE identifier (e.g., international mobile equipment identity (IMEI)), a user identity (e.g., IMSI), an APN, and/or a PDP context or EPS bearer ID. 
       FIGS. 3A and 3B  are block diagrams of roaming architectures for E-UTRAN including a visited centralized node (V-CICF)  310  and a home centralized node (H-CICF)  312  according to certain embodiments. The V-CICF  310  is in a visited PLMN (VPLMN)  314  and the H-CICF  312  is in a home PLMN (HPLMN)  316 . In this example, the one or more UEs  226  wirelessly communicate with the eNodeB  212  in the VPLMN  314 . Similar to the discussion of the PLMN  200  shown in  FIG. 2 , the VPLMN  314  includes the MME  214 , the S-GW  216 , the SGSN  218 , and the O&amp;M  220 , along with their respective interfaces S 101 , S 102 , S 103 , S 104 , S 105 . An interface S 108  is between the V-CICF  310  in the VPLMN  314  and the H-CICF  312  in the HPLMN  316 . 
       FIG. 3A  illustrates a home-routed roaming architecture for E-UTRAN where the HPLMN  316  includes the P-GW  222  and the PCRF  224 , along with their respective interfaces S 106 , S 107 .  FIG. 3B  illustrates a local-breakout roaming architecture for E-UTRAN where the VPLMN  314  includes the P-GW  222 , along with the interface S 106  between the V-CICF  310  and the P-GW  222 . The local-breakout roaming architecture also includes a visited PCRF (V-PCRF)  318  having an interface S 107 ( a ) with the V-CICF  310  in the VPLMN  314 , and a home PCRF (H-PCRF)  320  having an interface S 107 ( b ) with the H-CICF  312  in the HPLMN  316 . 
     In both roaming architectures shown in  FIGS. 3A and 3B , the V-CICF  310  collects and stores the RCI from the network elements located in the V-PLMN  314 . The H-CICF  312  collects and stores the RCI from network elements located in the H-PLMN  316 . In the home-routed roaming architecture shown in  FIG. 3A , the V-CICF  310  sends its RCI to the H-CICF  312  through the interface S 108 , and the H-CICF  312  provides both the RCI that the V-CICF  310  has collected and the RCI that the H-CICF has collected to the PCRF  224 . In response, the PCRF  224  implements policies for congestion mitigation in the HPLMN  316  and/or the VPLMN  314 . In the local-breakout roaming architecture shown in  FIG. 3B , the V-CICF  310  sends its stored RCI to the V-PCRF  318  through the interface S 107 ( a ), and the H-CICF  312  sends its stored RCI to the H-PCRF  320  through the interface S 107 ( b ). In response, the V-PCRF  318  implements policies for congestion mitigation in the VPLMN  314 , and the H-PCRF  320  implements policies for congestion mitigation in the HPLMN  316 . 
       FIG. 4  is a block diagram of an architecture for GERAN/UTRAN including a centralized node (CICF)  210  according to one embodiment. In this example, the one or more UEs  226  wirelessly communicate through a GERAN  412  and/or a UTRAN  414  (e.g., Node B) within a PLMN  400 . 
     Similar to the discussion of the PLMN  200  shown in  FIG. 2 , the PLMN  400  includes an interface S 104  between the CICF  210  and an SGSN  218 , and an interface S 105  between the CICF  210  and an O&amp;M system  220 . The PLMN  400  also includes an interface S 109  between the CICF  210  and the GERAN  412 , an interface S 110  between the CICF  210  and UTRAN  414 , and an interface S 111  between the CICF  210  and a GGSN  416 . Although not shown, the interface S 107  defined for the E-UTRAN architecture shown in  FIG. 2  can also be used for the GERAN/UTRAN architecture shown in  FIG. 4 . 
     The CICF  210  collects and stores RCI. Based on the stored RCI, according to certain embodiments, the CICF  210  triggers the PCRF (not shown) to modify an IP-CAN session. As discussed above with respect to  FIG. 2 , the PCRF may then provide policies for congestion mitigation. 
     B. Example Procedures for E-UTRAN to Report RCI to the Core Network 
       FIGS. 5A and 5B  illustrate example processes for reporting RCI via the control plane according to certain embodiments. In  FIG. 5A , the P-GW  222  reports RCI to the CICF  210  via the control plane (e.g., S1-MME, S11, and/or S5/S8). The P-GW  222  includes a policy and charging enforcement function (PCEF). The process includes the eNodeB  212  reporting  510  the RCI to the MME  214 , which responds by reporting  512  an acknowledgment (Ack). The MME  214  reports  514  the RCI to the S-GW  216 , which responds by reporting  516  Ack. The S-GW  216  reports  518  the RCI to the P-GW  222 , which responds by reporting  520  Ack. The P-GW  222  may also respond to receiving the RCI by triggering an IP-CAN session modification procedure to accommodate a changed user plane congestion condition. The P-GW  222  reports  522  the RCI to the CICF  210 , which responds by reporting  524  Ack. 
     In  FIG. 5B , the MME  214  reports RCI to the CICF  210  via the control plane (e.g., S1-MME). The process includes the eNodeB  212  reporting  526  the RCI to the MME  214 , which responds by reporting  528  Ack. The MME  214  may also respond to receiving the RCI by triggering an IP-CAN session modification procedure to accommodate a changed user plane congestion condition. The MME  214  reports  530  the RCI to the CICF  210 , which responds by reporting  532  Ack. 
       FIGS. 6A and 6B  illustrate example processes for reporting RCI via the user plane according to certain embodiments. In  FIG. 6A , the P-GW  222  reports RCI to the CICF  210  via the user plane. The process includes the eNodeB  212  reporting  610  the RCI in the GTP-U extension header via the user plane to the S-GW  216 , which responds by reporting  612  Ack. The S-GW  216  reports  614  the RCI in the GTP-U extension header via the user plane to the P-GW  222 , which responds by reporting  616  Ack. The P-GW  222  may also respond to receiving the RCI by triggering an IP-CAN session modification procedure to accommodate a changed user plane congestion condition. When the P-GW  222  perceives the RCI, the P-GW  222  reports  618  the RCI to the CICF  210 , which responds by reporting  620  Ack. 
     In  FIG. 6B , the S-GW  216  reports RCI to the CICF  210  via the user plane. The process includes the eNodeB  212  reporting  622  the RCI in the GTP-U extension header via the user plane to the S-GW  216 , which responds by reporting  624  Ack. If the reported RCI indicates S1-U congestion, the S-GW  216  may modify QoS mapping on S1-U and handle that internally. The S-GW  216  may also respond to receiving the RCI by triggering an IP-CAN session modification procedure to accommodate a changed user plane congestion condition. When the S-GW  216  perceives the RCI, the S-GW  216  reports  626  the RCI to the CICF  210 , which responds by reporting  628  Ack. 
       FIGS. 7A and 7B  illustrate example processes for reporting RCI using policy and charging control (PCC) according to certain embodiments. In  FIG. 7A , RCI is reported to the CICF  219  via the PCRF  224  and PCEF collocated with the RAN node. The process includes the eNodeB  212  and PCEF collocated with the RAN node reporting  710  the RCI to the PCRF  224 , which responds by reporting  712  Ack. When the PCRF  224  receives the report, the PCRF may initiate an IP-CAN session modification procedure to accommodate or apply PCC rules provisioned in the PCEF. The PCRF  224  reports  714  the RCI to the CICF  210 , which responds by reporting  716  Ack. 
     In  FIG. 7B , RCI is reported to the CICF  210  via a proxy  718  and the PCRF  224 . The proxy  718  may be, for example, an O&amp;M server, an ANDSF server, a new server, an MME, or one or more other network element configured to collect RCI from the RAN side. The process includes the eNodeB  212  reporting  720  the RCI to the proxy  718 , which responds by reporting  722  Ack. When the proxy  718  receives the reported RCI, the proxy  718  may trigger a UE or the PCRF  224  to enable a related provisioned rule or initiate a relative rule provision or modification procedure. The proxy  718  reports  724  the RCI to the PCRF  224 , which responds by reporting  726  Ack. The PCRF  224  reports  728  the RCI to the CICF  210 , which responds by reporting  730  Ack. 
       FIGS. 8A, 8B, and 8C  illustrate example processes for reporting RCI via the network management plane according to certain embodiments. In  FIG. 8A , RCI is reported to the CICF  210  directly from the RAN node. The process includes the eNodeB  212  reporting  810  the RCI to the CICF  210 , which responds by reporting  812  Ack. In  FIG. 8B , RCI is reported to the CICF  210  via a server  814 . The server  814  may be, for example, an ANDSF server, an O&amp;M server, or a new type of server. The process includes the eNodeB  212  reporting  816  the RCI to the server  814 , which responds by reporting  818  Ack. The server  814  reports  820  the RCI to the CICF  210 , which responds by reporting  822  Ack. In  FIG. 8C , RCI is reported to the CICF  210  via the proxy  718  and the server  814 . The process includes the eNodeB  212  reporting  824  the RCI to the proxy  718 , which responds by reporting  826  Ack. The proxy  718  reports  828  the RCI to the server  814 , which responds by reporting  830  Ack. The server  814  reports  832  the RCI to the CICF  210 , which responds by reporting  834  Ack. 
     C. Example Procedures for GERAN/UTRAN to Report RCI to the Core Network 
       FIGS. 9A and 9B  illustrate example processes for reporting RCI via the control plane according to certain embodiments. The following examples apply to a GERAN/UTRAN  912 . See, for example, the architecture shown in  FIG. 4 . In  FIG. 9A , the GGSN  416  reports RCI to the CICF  210  via the control plane. The process includes the GERAN/UTRAN  912  reporting  914  the RCI to the SGSN  218 , which responds by reporting  916  Ack. The SGSN  218  reports  918  the RCI to the GGSN  416 , which responds by reporting  920  Ack. The GGSN  416  may also respond to receiving the RCI by triggering a context modification procedure to accommodate a changed user plane congestion condition. The GGSN  416  reports  922  the RCI to the CICF  210 , which responds by reporting  926  Ack. 
     In  FIG. 9B , the SGSN  218  reports RCI to the CICF  210  via the control plane. The process includes the GERAN/UTRAN  912  reporting  914  the RCI to the SGSN  218 , which responds by reporting  930  Ack. The SGSN  218  may also respond to receiving the RCI by triggering PDP context and/or an IP-CAN session modification procedure to accommodate a changed RAN user plane congestion condition. The SGSN  218  reports  932  the RCI to the CICF  210 , which responds by reporting  934  Ack. 
       FIGS. 10A and 10B  illustrate example processes for reporting RCI via the user plane according to certain embodiments. In  FIG. 10A , the GGSN  416  reports RCI to the CICF  210  via the user plane. The process includes the GERAN/UTRAN  912  reporting  1010  the RCI in the GTP-U extension header via the user plane to the SGSN  218 , which responds by reporting  1012  Ack. The SGSN  218  reports  1014  the RCI in the GTP-U extension header via the user plane to the GGSN  416 , which responds by reporting  1016  Ack. The GGSN  416  may also respond to receiving the RCI by triggering a context modification procedure to accommodate a changed user plane congestion condition. The GGSN  416  reports  1018  the RCI to the CICF  210 , which responds by reporting  1020  Ack. 
     In  FIG. 10B , the SGSN  218  reports RCI to the CICF  210  via the user plane. The process includes the GERAN/UTRAN  912  reporting  1022  the RCI in the GTP-U extension header via the user plane to the SGSN  218 , which responds by reporting  1024  Ack. The SGSN  218  may also respond to receiving the RCI by triggering PDP context and/or an IP-CAN session modification procedure to accommodate a changed RAN user plane congestion condition. The SGSN  218  reports  1026  the RCI to the CICF  210 , which responds by reporting  1028  Ack. 
       FIGS. 11A and 11B  illustrate example processes for reporting RCI using PCC according to certain embodiments. 
     In  FIG. 11A , RCI is reported to the CICF  219  via the PCRF  224  and a PCEF collocated with the RAN node. The process includes the GERAN/UTRAN  912  and PCEF collocated with the RAN node reporting  1110  the RCI to the PCRF  224 , which responds by reporting  1112  Ack. When the PCRF  224  receives the report, the PCRF may initiate an IP-CAN session modification procedure to accommodate or apply PCC rules provisioned in the PCEF. The PCRF  224  reports  1114  the RCI to the CICF  210 , which responds by reporting  1116  Ack. 
     In  FIG. 11B , RCI is reported to the CICF  210  via the proxy  1118  and the PCRF  224 . The proxy  1118  may be, for example, an O&amp;M server, an ANDSF server, a new server, or one or more other network elements configured to collect RCI from the RAN side. The process includes the GERAN/UTRAN  912  reporting  1120  the RCI to the proxy  1118 , which responds by reporting  1122  Ack. When the proxy  1118  receives the reported RCI, the proxy  1118  may trigger a UE or the PCRF  224  to enable a related provisioned rule or initiate a relative rule provision or modification procedure. The proxy  1118  reports  1124  the RCI to the PCRF  224 , which responds by reporting  1126  Ack. The PCRF  224  reports  1128  the RCI to the CICF  210 , which responds by reporting  1130  Ack. 
       FIGS. 12A, 12B, and 12C  illustrate example processes for reporting RCI via the network management plane according to certain embodiments. In  FIG. 12A , RCI is reported to the CICF  210  directly from the RAN node. The process includes the GERAN/UTRAN  912  reporting  1210  the RCI to the CICF  210 , which responds by reporting  1212  Ack. In  FIG. 12B , RCI is reported to the CICF  210  via a server  1214 . The server  1214  may be, for example, an ANDSF server, an O&amp;M server, or a new type of server. The process includes the GERAN/UTRAN  912  reporting  1216  the RCI to the server  1214 , which responds by reporting  1218  Ack. The server  1214  reports  1220  the RCI to the CICF  210 , which responds by reporting  1222  Ack. In  FIG. 12C , RCI is reported to the CICF  210  via the proxy  1118  and the server  1214 . The process includes the GERAN/UTRAN  912  reporting  1224  the RCI to the proxy  1118 , which responds by reporting  1226  Ack. The proxy  1118  reports  1228  the RCI to the server  1214 , which responds by reporting  1230  Ack. The server  1214  reports  1232  the RCI to the CICF  210 , which responds by reporting  1234  Ack. 
     D. Example CICF Procedures 
     In one embodiment, a CICF collects RCI directly from a RAN node or from one or more other network elements such as an O&amp;M system, an ANDSF server, a different or new type of server, an MME, an S-GW, an SGSN, a GGSN, and/or a P-GW. The CICF stores the RCI for a period of time, and discovers one or more proper PCRFs for UEs impacted by user plane congestion. The CICF also queries for and receives a list of UEs and related APNs for each UE from the MME and SGSN by supplying a cell ID (cell global ID). 
       FIG. 13  illustrates an example process for a CICF  210  to manage RCI in a core network according to one embodiment. In this example, the CICF  210  communicates with one or more MME/SGSN  1310  and one or more PCRF  1312  (such as the MME  214 , SGSN  218 , and PCRF  224  shown in  FIG. 2 ). In summary, the process includes the CICF  210  receiving  1314  one or more RAN congestion information event or report, determining  1316  impacted UEs and APNs, and reporting  1318  RCI to the one or more PCRF  1312 . 
     As discussed in detail above, there are several embodiments for the CICF  210  to receive  1314  one or more RAN congestion information event or report. See, for example,  FIGS. 5A-8C . In addition, or in other embodiments, an event or report is sent to the CICF  210  due to a change of radio node/cell user plane congestion status (e.g., when a pre-configured congestion/congestion abatement threshold has been reached). This notification includes an indication of the affected area (e.g., ENB-ID or service area ID), as well as the congestion level. The CICF  210  may also solicit the RCI based on a configured interval. In certain embodiments, one or more CICFs is configured to serve a geographical area. 
     The CICF  210  determines  1316  the list of UEs impacted by the RAN congestion in a cell by communicating with the one or more MME/SGSN  1310 . In certain E-UTRAN embodiments, the CICF  210  subscribes onto an MME to get a list of UEs in the affected area. To achieve this, the CICF  210  constructs a tracking area identity (TAI) based fully qualified domain name (FQDN) for MME discovery. The CICF  210  may, for example, receive the TAIs supported by the affected area from the RAN&#39;s O&amp;M. 
     The CICF  210  receives the list of MMEs serving the TAIs supported by the affected area and establishes an interface (e.g., the interface S 102  shown in  FIG. 2 ) towards those MMEs. Once the interface has been established, the CICF  210  queries via the interface for the list of UEs in the affected area. In response, the MMEs provide the list of IMSIs and the list of APNs of the active PDN connections of each of those IMSIs to the CICF  210 . In certain embodiments, the CICF  210  does not need to remember the list of IMSI(s) (and their activated APN) as it is refreshed each time the CICF  210  interacts with the MME. The CICF  210  uses the list of APNs of the UEs&#39; active PDN connections to discover the serving PCRFs. 
     For E-UTRAN embodiments, the CICF  210  also indicates whether it requests the list of UEs per ECGI or eNB ID. Consequently, depending on the level of granularity requested by the CICF  210 , the MME may need (or may not need) to activate location reporting over S1-AP. Whether the CICF  210  requests the list of UEs per ECGI or eNB ID may, for example, be based on local configuration. 
     For UTRAN embodiments, the CICF  210  receives the list of UEs (IMSIs) impacted by a change of RCI in a cell from the RAN&#39;s O&amp;M. The O&amp;M may have received this information from the RAN (e.g., the IMSI is sent by the SGSN over the Iu interface in a radio access network application part (RANAP) common ID message). Thus, in certain UTRAN embodiments, the CICF  210  queries the SGSN only for the APNs of the active PDN connections of a given impacted IMSI. To achieve this according to certain embodiments, the CICF  210  constructs a routing area identity (RAI) based FQDN for SGSN discovery. The CICF  210  may, for example, receive the RAIs supported by the affected area from the RAN&#39;s O&amp;M. 
     The CICF  210  receives the list of SGSNs serving the RAIs supported by the affected area and establishes an interface (e.g., the interface S 104  shown in  FIG. 2 ) towards those SGSNs. Once the interface has been established, the CICF  210  passes the list of UEs (IMSIs) in the congested area to the SGSNs. In response, the SGSNs provide the list of APNs of the active PDN connections of each of the reported IMSIs to the CICF  210 . The CICF  210  uses the list of APNs of the UEs&#39; active PDN connections to discover the serving PCRFs. 
     It should be noted that as both temporal and “spatial” integration are provided, the RCI sent to the PCRF according to certain embodiments does not intend to provide the PCRF with information on the instantaneous congestion status in a given cell. This may be consistent with the information being used to act on a sustained congestion status in an area. In some cases, the PCRF still considers that a fast moving UE is in a congested area while the UE has already moved to a non-congested area. It should also be noted that in some scenarios, the core network may not know all the cells and/or eNodeBs that a given UE is using (multi-site CA, small cells). As a consequence, in certain embodiments, the RCI reporting may not reflect the actual congestion status of all the cells from which the UE is currently using resources. 
     In certain embodiments, the CICF  210  may, based on local policies, further process the information received from the RAN in order to build the RCI. For example, the CICF  210  may integrate the RAN congestion status based on time (e.g., to provide the PCRF  210  only with sustained congestion levels). In addition, or in another embodiment, the CICF  210  may provide “spatial” integration of the RAN congestion information due to mobility and to the UE possibly being served by multiple cells (e.g., due to multi-cell carrier aggregation). Thus, the RCI associated with a cell may depend on the congestion status in the neighboring cells. As another example for LTE, as many RAN features (e.g., carrier aggregation, CoMP, etc.) may involve multiple cells of an eNodeB and as intra-eNodeB mobility reporting is generally not activated (e.g., to save signaling), RCI at the eNodeB level may provide enough information. This does not, however, preclude RCI reporting at the cell level. In an example embodiment of network sharing, the CICF  210  and the PCRF belong to different operators. The CICF  210  may apply local policies related to the information it sends to PCRFs of different operators. In another example embodiment, the CICF  210  uses the IMSI to determine the PLMN of the UE and whether it should apply local policies related to the information it sends to PCRFs of different operators. In another example embodiment cased on local policies, the RCI being sent may also depend on the relative RAN usage of the various operators sharing RAN resources. 
     In the process shown in  FIG. 13 , the CICF reports  1318  RCI to the PCRFs that are serving the impacted UEs. In certain embodiments, the CICF  210  reports RCI per IMSI/APN to the PCRFs. Based on the list of impacted UEs (IMSIs) and on the list of APNs of their active PDN connections, the CICF  210  notifies the PCRFs serving those UEs and APN(s). In embodiments with networks including multiple PCRFs, a diameter routing agent (DRA) may be deployed. The CICF  210  use the DRA to contact the PCRF(s). When the Gx interface gets established, the DRA “assigns” a PCRF for a given IMSI/APN combination and remembers the relationship (e.g., IMSI, APN, selected PCRF). Based on this relationship, DRAs support finding the PCRF serving an IMSI/APN combination. 
     III. Additional Example Embodiments 
     The following are examples of further embodiments: 
     In Example 1, a core network node in a wireless communication system. The core network node comprises a first interface, a second interface, and a third interface. The first interface to receive RCI. The core network node to determine a UE associated with the RCI. The second interface to communicate with an SGSN. The core network node to identify the UE to the SGSN through the second interface. The core network node to receive an APN corresponding to the UE from the SGSN. The third interface to report the RCI to a PCRF associated with the APN for congestion mitigation. 
     Example 2 includes the core network node of Example 1, wherein the wireless communication system comprises an E-UTRAN. The core network node further comprising a fourth interface to communicate with an MME. To determine the UE, the core network node is configured to receive a UE identifier from the MME through the fourth interface. 
     Example 3 includes the core network node of Example 1, wherein the wireless communication system comprises a UTRAN and GERAN. To determine the UE, the core network node is configured to receive a UE identifier from an O&amp;M system of the RAN. 
     Example 4 includes the core network node of Examples 2 or 3, wherein the UE identifier comprises an IMSI corresponding to the UE associated with the RCI. 
     Example 5 includes the core network node of Example 1, wherein the RCI includes one or more IE selected from a group comprising a first IE for a congested interface direction and node, a second IE for a congestion severity level, a third IE for a congestion situation indicating a change in whether or not congestion is detected, a fourth IE for congestion cell location information, a fifth IE for identifying the UE, a sixth IE for identifying a user associated with the UE, a seventh IE for identifying the APN, an eighth IE for PDP context information, and a ninth IE for an EPS bearer identifier. 
     Example 6 includes the core network node of Example 5, wherein the first IE for the congested interface direction and node includes at least one interface or node identifier selected from a group comprising a radio interface downlink identifier, a radio interface uplink identifier, a network interface downlink identifier, a network interface uplink identifier, a RAN node identifier. 
     Example 7 includes the core network node of Example 5, wherein the fifth IE for identifying the UE comprises an IMEI, and wherein the sixth IE for identifying a user associated with the UE comprises an IMSI. 
     Example 8 includes the core network node of Example 1, and further includes a memory device to store the RCI received through the first interface, and a processor to process the stored RCI and to trigger the PCRF to modify an IP-CAN session. 
     In Example 9 a method for user plane congestion awareness in a mobile network includes receiving and storing an event or report indicating a change in a radio node or cell user plane congestion status. The event or report includes an indication of one or more congested areas and corresponding congestion levels. The method further includes determining, based on the received event or report, a list of UEs and associated active connections in the one or more congested areas, identifying one or more network elements configured to adjust a QoS for the one or more congested areas, respectively, and communicating user plane congestion information to the one or more identified network elements serving the list of UEs. 
     Example 10 includes the method of Example 9, wherein receiving and storing the event or report comprises receiving the event or report from a RAN, and storing the event or report for a predetermined period of time. 
     Example 11 includes the method of Example 10, and further includes sending a request to the RAN for the event or report based on a configured time interval. 
     Example 12 includes the method of Example 9, wherein receiving and storing the event or report comprises receiving the event or report from one or more network elements selected from a group comprising an O&amp;M system, an ANDSF server, an MME, an S-GW, an SGSN, a GGSN, and a P-GW. 
     Example 13 includes the method of Example 9, wherein determining the list of UEs comprises determining one or more MMEs associated with the one or more congested areas, establishing an interface toward the one or more MMEs, querying, via the interface, for the list of UEs, and receiving, via the interface, a list of IMSIs associated with the list of UEs. 
     Example 14 includes the method of Example 13, and further includes receiving, via the interface, a list of APNs of the associated active connections corresponding the list of IMSIs, and using the list of APNs to identify the one or more network elements configured to adjust the QoS for the one or more congested areas, wherein the one or more elements comprise respective PCRF nodes. 
     Example 15 includes the method of Example 13, wherein determining the one or more MMEs associated with the one or more congested areas comprises determining TAIs based FQDN for MME discovery, and receiving, from an O&amp;M system of a RAN, a list of the TAIs supported by the one or more congested areas. 
     Example 16 includes the method of Example 9, wherein determining the list of UEs comprises receiving, from an O&amp;M system of a RAN, a list of IMSIs associated with the list of UEs, determining one or more SGSNs associated with the one or more congested areas, establishing an interface toward the one or more SGSNs, querying, via the interface, a list of APNs of the associated active connections corresponding the list of IMSIs and using the list of APNs to identify the one or more network elements configured to adjust the QoS for the one or more congested areas. The one or more elements comprise respective PCRF nodes. 
     In Example 17 a server includes a processor, a storage device, and a CICF. The storage device to store an indication that demand for radio access network resources exceeds available capacity in an identified area of a wireless cellular network. The CICF comprises instructions that, when executed by the processor, manage congestion information for the wireless cellular network. The CICF configured to discover an MME serving the identified area of the wireless cellular network, request and receive, from the MME, a list of IMSIs associated with the identified area of the wireless cellular network, discover a network node associated with the list of IMSIs and configured to initiate an IP-CAN session modification procedure, and notify the network node configured to initiate the IP-CAN session modification of the demand for radio access network resources. 
     Example 18 includes the server of Example 17, wherein the CICF is further configured to receive, from an O&amp;M system, the indication that demand for radio access network resources exceeds available capacity. 
     Example 19 includes the server of Example 18, wherein the CICF is further configured to receive, from the O&amp;M system, TAI supported by the identified area of the wireless cellular network, and use the TAI to discover the MME. 
     Example 20 includes the server of Example 17, wherein the CICF is further configured to receive, from the MME in response to the request for the list of IMSIs, a corresponding list of APNs of active PDN connections. 
     Example 21 includes the server of Example 20, wherein the discovered network node associated with the list of IMSIs comprises a PCRF associated with the APNs. 
     Example 22 includes the server of Example 17, wherein the CICF is further configured to receive the indication that demand for radio access network resources exceeds available capacity through one or more interface selected from a group comprising a user plane interface, a control plane interface, and a network management plane interface. 
     In Example 23 an RCAF node in a core network of a wireless communication system includes means for receiving and storing an event or report indicating a change in a radio node or cell user plane congestion status. The event or report including an indication of one or more congested areas and corresponding congestion levels. The RCAF further includes means for determining, based on the received event or report, a list of UEs and associated active connections in the one or more congested areas, means for identifying one or more network elements configured to adjust a QoS for the one or more congested areas, respectively, and means for communicating user plane congestion information to the one or more identified network elements serving the list of UEs. 
     Example 24 includes the RCAF node of Example 23, and further includes means for receiving the event or report from a RAN, and means for storing the event or report for a predetermined period of time. 
     Example 25 includes the RCAF node of Example 24, and further includes means for sending a request to the RAN for the event or report based on a configured time interval. 
     Example 26 includes the RCAF node of Example 23, wherein receiving and storing the event or report comprises receiving the event or report from one or more network elements selected from a group comprising an O&amp;M system, an ANDSF server, an MME, an S-GW, a SGSN, a GGSN, and a P-GW. 
     Example 27 includes the RCAF node of Example 23, and further includes means for determining one or more MMEs associated with the one or more congested areas, means for establishing an interface toward the one or more MMEs, means for querying, via the interface, for the list of UEs, and means for receiving, via the interface, a list of IMSIs associated with the list of UEs. 
     Example 28 includes the RCAF node of Example 27, and further includes means for receiving, via the interface, a list of APNs of the associated active connections corresponding the list of IMSIs, and means for using the list of APNs to identify the one or more network elements configured to adjust the QoS for the one or more congested areas, wherein the one or more elements comprise respective PCRF nodes. 
     Example 29 includes the RCAF node of Example 27, and further includes means for determining TAI based FQDN for MME discovery, and means for receiving, from an O&amp;M system of a RAN, a list of the TAIs supported by the one or more congested areas. 
     Example 30 includes the RCAF node of Example 23, and further includes means for receiving, from an O&amp;M system of a RAN, a list of IMSIs associated with the list of UEs, means for determining one or more SGSNs associated with the one or more congested areas, means for establishing an interface toward the one or more SGSNs, means for querying, via the interface, a list of APNs of the associated active connections corresponding the list of IMSIs, and means for using the list of APNs to identify the one or more network elements configured to adjust the QoS for the one or more congested areas, wherein the one or more elements comprise respective PCRF nodes. 
     In Example 31 a method includes receiving RCI through a first interface, determining a UE associated with the RCI, communicating through a second interface with an SGSN an identity of the UE, receiving an APN corresponding to the UE from the SGSN, and reporting through a third interface the RCI to a PCRF associated with the APN for congestion mitigation. 
     Example 32 includes the method of Example 31, and further includes communicating, through a fourth interface, with a MME. Determining the UE comprises receiving a UE identifier from the MME through the fourth interface. 
     Example 33 includes the method of Examples 32, wherein the UE identifier comprises an IMSI corresponding to the UE associated with the RCI. 
     Example 34 includes the method of Example 31, wherein the RCI includes one or more IE selected from a group comprising a first IE for a congested interface direction and node, a second IE for a congestion severity level, a third IE for a congestion situation indicating a change in whether or not congestion is detected, a fourth IE for congestion cell location information, a fifth IE for identifying the UE, a sixth IE for identifying a user associated with the UE, a seventh IE for identifying the APN, an eighth IE for PDP context information, and a ninth IE for an EPS bearer identifier. 
     Example 35 includes the method of Example 34, wherein the first IE for the congested interface direction and node includes at least one interface or node identifier selected from a group comprising a radio interface downlink identifier, a radio interface uplink identifier, a network interface downlink identifier, a network interface uplink identifier, a RAN node identifier. 
     Example 36 includes the method of Example 34, wherein the fifth IE for identifying the UE comprises an IMEI, and wherein the sixth IE for identifying a user associated with the UE comprises an IMSI. 
     Example 37 includes the method of Example 31, and further includes receiving the RCI through the first interface, and processing the RCI and triggering the PCRF to modify an IP-CAN session. 
     In Example 38, an apparatus includes means to perform a method as claimed in any of Examples 9-16 or 31-37. 
     In Example 39, a machine-readable storage including machine-readable instructions, when executed, to implement a method or realize an apparatus as claimed in any preceding Example. 
     Various techniques described herein, or certain aspects or portions thereof, may take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, a non-transitory computer readable storage medium, or any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the various techniques. In the case of program code execution on programmable computers, the computing device may include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. The volatile and non-volatile memory and/or storage elements may be a RAM, an EPROM, a flash drive, an optical drive, a magnetic hard drive, or another medium for storing electronic data. The eNB (or other base station) and UE (or other mobile station) may also include a transceiver component, a counter component, a processing component, and/or a clock component or timer component. One or more programs that may implement or utilize the various techniques described herein may use an application programming interface (API), reusable controls, and the like. Such programs may be implemented in a high-level procedural or an object-oriented programming language to communicate with a computer system. However, the program(s) may be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language, and combined with hardware implementations. 
     It should be understood that many of the functional units described in this specification may be implemented as one or more components, which is a term used to more particularly emphasize their implementation independence. For example, a component may be implemented as a hardware circuit comprising custom very large scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A component may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, or the like. 
     Components may also be implemented in software for execution by various types of processors. An identified component of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions, which may, for instance, be organized as an object, a procedure, or a function. Nevertheless, the executables of an identified component need not be physically located together, but may comprise disparate instructions stored in different locations that, when joined logically together, comprise the component and achieve the stated purpose for the component. 
     Indeed, a component of executable code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within components, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network. The components may be passive or active, including agents operable to perform desired functions. 
     Reference throughout this specification to “an example” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of the present invention. Thus, appearances of the phrase “in an example” in various places throughout this specification are not necessarily all referring to the same embodiment. 
     As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on its presentation in a common group without indications to the contrary. In addition, various embodiments and examples of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention. 
     Although the foregoing has been described in some detail for purposes of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles thereof. It should be noted that there are many alternative ways of implementing both the processes and apparatuses described herein. Accordingly, the present embodiments are to be considered illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims. 
     Those having skill in the art will appreciate that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.

Metadata:
Filing Date: 20140328
Publication Date: 20200428
Grant Date: 20200428
Priority Date: 20130426
Inventors: SHAN, CHANG HONG
Assignee: APPLE INC
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