FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“SYSTEM AND METHOD OF DETERMINING LOCATION OF AN INTERNATIONAL IN-ROAMING SUBSCRIBER”
We, RELIANCE JIO INFOCOMM LIMITED, an Indian National, of 3rd Floor, Maker Chamber-IV, 222, Nariman Point, Mumbai- 400021, Maharashtra, India.
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
The present disclosure relates generally to wireless communication and more particularly, to a method and system for determining location of an international in-roaming subscriber user equipment.
BACKGROUND OF THE DISCLOSURE
The following description of related art is intended to provide background information pertaining to the field of the disclosure. This section may include certain aspects of the art that may be related to various features of the present disclosure. However, it should be appreciated that this section be used only to enhance the understanding of the reader with respect to the present disclosure, and not as admissions of prior art.
Wireless communication networks are widely deployed to provide voice as well as data services. These wireless networks may be multiple-access networks which are capable of supporting multiple users by sharing the available network resources. Examples of multiple access network formats include Universal Terrestrial Radio Access Network (UTRAN), Evolved UTRAN (E-UTRAN), Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) Networks, and Single-Carrier FDMA (SCFDMA) networks.
A typical wireless communication network may include a number of base stations or eNodeB that can support voice and data communication for multiple user equipment (UEs). In a traditional cellular deployment, suitable powered macrocells are being deployed to cover sufficiently large areas. However, with macrocells only deployment, it generally suffers from quick capacity degradation as the number of user equipment (UE) operating in the macrocells coverage areas increase.

The evolved UMTS Terrestrial Radio Access (E-UTRA) of the long term evolution (LTE) is an entirely new air interface system, unlike the High-Speed Packet Access (HSPA), which is unrelated to and incompatible with the wireless code division multiple access (WCDMA). It provides higher data rates, lower latency and is optimized for packet data. The earlier UTRAN is the radio access network (RAN) was defined as a part of the UMTS, a third-generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP).
The UMTS technology, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as W-CDMA, Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as the HSPA, which provides higher data transfer speeds and capacity to associated UMTS networks. As the demand for mobile data and voice access is increasing, the research and development to advance these technologies are also upgrading, not only to meet the growing demand for access, but also to advance and enhance the user experience with a user device. A few of the technologies that have evolved starting with GSM/EDGE, UMTS/HSPA, CDMA2000/EV-DO and TD-SCDMA radio interfaces with the 3GPP Release 8, e-UTRA is designed to provide a single evolution path for providing enhancement in the data speeds, and spectral efficiency and allowing the provision of more functionality.
In recent years, there has been an immense proliferation of wireless devices
ecosystem that helps in providing both voice and data services simultaneously which is of much utility-oriented particularly for the countries where there are plurality of service providers. For e.g., the mobile devices allow the user to implement different service plans or service providers on the same mobile device. Further, the mobile device allows the user to obtain services while travelling outside the operating zones where the user may obtain roaming

services in those zones or targeted destinations. The user may take advantage of different pricing plans for data and voice and save on the voice and the data usage in roaming scenarios.
In an international roaming scenario, the LTE roaming architecture as shown in Fig. 1 is deployed. As shown in Fig. 1, the architecture shows a Home Public Land Mobile Network (HPLMN) [100A] and a Visited Public Land Mobile Network (VPLMN) [100B]. When a foreign operator subscriber user equipment [102] comes into or visits the VPLMN [100B], it latches to the Mobility Management Entity (MME) [104] of the VPLMN [100B] via the E-UTRAN [106]. The MME [104] of the VPLMN is configured to authenticate the foreign operator subscriber user equipment [102] by interacting with the Home Subscriber Server (HSS) [112] of the HPLMN [100A] over an S6a interface. Pursuant to the authentication, the foreign operator subscriber user equipment [102] successfully latches to the MME [104]. The HSS [112] of the HPLMN [100A] is aware of the MME [104] of the VPLMN [100B] to which the foreign operator subscriber user equipment [102] is latched.
In operation, when a foreign operator subscriber user equipment [102] wants to use voice or data services, a request is sent to the serving gateway [108] of the VPLMN [100B] via the E-UTRAN [106], wherein the serving gateway [108] checks if the request is coming from a roaming subscriber. This may be performed by analyzing the MCC/MNC of the user equipment from which the request is received and concluding that the request comes from a roaming subscriber if the MCC/MNC is not of the VPLMN [100B]. Once the serving gateway [108] determines that the request is received from foreign operator subscriber user equipment [102], the request is routed to the home PDN gateway [104] of the HPLMN [100A] over the S8 interface. The PDN gateway [114] then provides the requested services through the foreign operator subscriber user equipment [102]. Thus, voice and data services requested by a foreign operator subscriber user equipment [102] are anchored by the home IMS network itself.

As per the regulatory guidelines, all services (data as well as voice, video & messaging) of an in-roaming international subscriber should be intercepted at the respective roaming partner’s network where the subscriber is latched. In this case, the interception of data, as well as voice traffic takes place at the serving gateway [108]. In addition to this requirement, the location of international In-roaming subscriber also needs to be captured. For providing location of any subscriber, the location services (LCS) platform is currently used.
Typically, there are four categories of usage of the location service, i.e. (i) Commercial LCS, (ii) the Internal LCS, (ii) the Emergency LCS and (iv) the Lawful Intercept LCS. The Commercial LCS (or Value Added Services) will typically be associated with an application that provides a value-added service to the subscriber of the service, through knowledge of the UE location and the positioning method used to obtain the location (if allowed by the operator). The Internal LCS will typically be developed to make use of the location information of the UE for Access Network internal operations, for example, location assisted handover, etc. The Emergency LCS is typically part of a service provided to assist subscribers who place emergency calls. In this service, the location of the UE caller and, if available, the positioning method used to obtain the location estimate is provided to the emergency service provider to assist them in their response. This service may be mandatory in some jurisdictions. Lastly, the Lawful Intercept LCS will use the location information to support various legally required or sanctioned
services.
A typical call flow for a location query when a user equipment is in its home network, is shown in Fig. 2. As shown in Fig. 2, location information of a UE [216] may be requested by a lawful intercept (LI) client [202]. Such a location query request may be sent to a Gateway Mobile Location Centre (GMLC) [204] that is

configured to provide a network-based location to any requesting application. In order to determine the location, the GMLC [204] has to identify the MME to which the UE [216] is latched. Since MME is required to perform authentication with the Home Subscriber Server (HSS) [208], the HSS is aware of the MME [212] to which the UE [216] is currently latched. Thus, as a first step, the GMLC [204] sends a Routing Information Request to the HSS [208]. Upon receiving this request, the HSS [208] responds back with the Routing Information Answer comprising the current MME address. Thereafter, the GMLC [204] sends a location query Provide Subscriber Location to the MME [212]. To compute the location, the MME [212] sends the location to the Enhanced-Serving Mobile Location Center (ESMLC) [210], wherein the ESMLC [210] computes the current location of the UE [216] by standard positioning procedure and transmits the location response back to the MME [212]. The MME [212] then transmits the location information to the GMLC [204] which provides it further to the LI Client [202].
For a similar location query, when the user equipment is in the visited network, is more complex and challenging. There are techniques for finding the location of the User Equipment (UE) in international roaming environment to provide Location Based Services (LBS). In the existing solutions, for international in-roaming and out-roaming, the service operators are required to establish interconnect with a vendor, i.e. an international interconnect operator that provides the functionality of international roaming gateway. Such international interconnect operators provide interconnect with other International operators based on the location of the subscriber. Figure 3 shows the LTE roaming architecture wherein the VPLMN and the HPLMN are interconnected via international interconnect operator. As shown in Figure 3, the international in-roaming subscriber UE [102] in the VPLMN [100B] is latched on to an MME [104] via the E-UTRAN [106]. The UE [102] is also connected to the serving gateway [108] via the E-UTRAN [106]. In order to avail data and voice services, request

from the MME [102] is routed to the serving gateway [108] and is further routed to the PDN gateway [114] of the HPLMN [100A], via the international interconnect operator [300].
In the above scenario shown in Fig. 3, if a location query is received at the GMLC [204] of the VPLMN, such a query is to be routed to the home HSS [112] to receive the address of the serving MME [104]. As part of the 3GPP standards, S6a international roaming tie-up, SLh/Sh interface is not part of this implementation. For this reason, the service provider is not able to perform location query by itself for any international in-roaming subscriber latched on to its network and has to depend on the IPX Interconnect Gateway vendor for such location query of the international in-roaming subscriber on its network.
However, the issue with this approach is that the HSS [112] of the HPLMN [100A] does not allow access by any foreign operator. This is primarily because the HSS contains the subscriber data for all the subscribers of the network, and owing to the confidential nature of the data the HSS has restricted access for security reasons. To overcome this problem, the network operator is required to get in an agreement with each of the thousands of network operators throughout the world in order to gain access to query the HSS of such networks. This is not only time consuming but also very expensive to have an individual agreement between different operators such that it is impractical to take this approach.
Thus, collecting real-time location data of the international subscriber is a major challenge for the service provider, that may be required to provide the subscriber location data to multiple applications serving the subscriber. As per regulatory guidelines, all services of the in-roaming international subscriber are required to be intercepted at the roaming network where the subscriber is latched, due to which location information is necessary for the service provider.
Therefore, considering the need for capturing the location data of the in-roaming international subscriber and the limitations of the existing architecture, there

exists a need in the art to provide for a technical solution to determining a location of an in-roaming subscriber user equipment in a visited PLMN without having the need for the service provider/ operator in the VPLMN to enter into individual agreements with all other operators across the world.
SUMMARY OF THE DISCLOSURE
In order to overcome at least some of the drawbacks mentioned in the previous section and those otherwise known to persons skilled in the art, an object of the present disclosure is to provide a s solution for finding the location of a international in-roaming subscriber User Equipment (UE) and also to provide Location Based Services (LBS) by the service provider. Another object of the present invention is to reduce the cost of finding the location by not deploying any third-party vendor that will reduce the operation cost. Another object of the present invention is to support emergency scenarios like location-specific throttling, Location during emergency calling and barring based on the regulatory requirements. Yet another object of the present invention is to provide location-based control where network can control the access of subscriber in very flexible manner like from restricting one’s usage or to make allow access to all places except one and different combination thereof. Further, another object of the present invention is to provide solution on the basis of location such as location-specific plans, location-specific portal, location-specific advertisements, locations specific alerts and notification, location-specific analytics, predictive service, etc. Yet another object of the present invention is that the newly designed architecture provides solution for network operator that is independent of network vendor limited policies and provide an open platform where an operator can introduce number of location-based as well as aware use cases that are relevant to the given operator.
To accomplish these and other objectives, one aspect of the present disclosure relates to a method for determining a location of a first international in-roaming

subscriber user equipment. The method begins with receiving dynamically, at a proxy Home Subscriber Server (proxy HSS) from a Diameter Edge Agent (DEA), at least one location update message exchanged between a serving Mobility Management Entity (MME) and a Home Subscriber Server (HSS) for one or more international in-roaming subscriber user equipment. The proxy HSS processes the received at least one location update message to determine a current attach status of said one or more international in-roaming subscriber user equipment and stores the same. Thereafter, the proxy HSS receives a location query for said first international in-roaming subscriber user equipment from a location server via a Diameter Routing Agent (DRA). This location query is then processed by the proxy HSS to determine a serving MME address of said first international in-roaming subscriber user equipment based on said stored current attach status. Subsequently, the proxy servers transmit said determined serving MME address to the location server, wherein the location of the first international in-roaming subscriber user equipment is determined using said serving MME address.
Another aspect of the present disclosure relates to a proxy Home Subscriber Server (HSS) to determine a location of a first international in-roaming subscriber user equipment. The proxy HSS comprises at least a transceiver unit configured to receiving dynamically from a Diameter Edge Agent (DEA), at least one location update message exchanged between a serving Mobility Management Entity (MME) and a Home Subscriber Server (HSS) for one or more international in-roaming subscriber user equipment. The proxy HSS further comprises a processing unit connected to said transceiver unit, said processing unit configured to process said received at least one location update message to determine a current attach status of said one or more international in-roaming subscriber user equipment. Further, the proxy HSS also comprises a memory unit connected to said transceiver unit and said processing unit, the memory unit configured to store said determined current attach status of said one or more international in-roaming subscriber user equipment. The transceiver unit is

further configured to receive from a location server via a Diameter Routing Agent (DRA), a location query for said first international in-roaming subscriber user equipment. Also, the processing unit is further configured to process said location query to determine a serving MME address of said first international in-roaming subscriber user equipment based on said stored current attach status, wherein the transceiver unit is further configured to transmit to the location server, said determined serving MME address, wherein the location of the first international in-roaming subscriber user equipment is determined using said serving MME address.
Yet another aspect of the present disclosure relates to a method for determining a location of a first international in-roaming subscriber user equipment. The method begins with receiving, at a Diameter Edge Agent (DEA), at least one location update message exchanged between a serving MME and a home HSS for one or more international in-roaming subscriber user equipment. This location update message is duplicated by the DEA and dynamically transmitted to a proxy HSS. Thereafter, the proxy HSS processes said received duplicated at least one location update message to determine a current attach status of said one or more international in-roaming subscriber user equipment; and stores the same. Subsequently, a location query for said first international in-roaming subscriber user equipment is received at a location server, and is transmitted by the location server to the proxy HSS via a DRA. The proxy HSS then processes said location query to determine a serving MME address of said first international in-roaming subscriber user equipment based on said stored current attach status; and transmits said determined serving MME address to the location server. Lastly, the location server retrieves from said serving MME, the location of the first international in-roaming subscriber user equipment.
BRIEF DESCRIPTION OF DRAWINGS
The accompanying drawings, which are incorporated herein, and constitute a

part of this disclosure, illustrate exemplary embodiments of the disclosed methods and systems in which like reference numerals refer to the same parts throughout the different drawings. Components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Some drawings may indicate the components using block diagrams and may not represent the internal circuitry of each component. It will be appreciated by those skilled in the art that disclosure of such drawings includes disclosure of electrical components, electronic components or circuitry commonly used to implement such components.
Figure 1 illustrates the current LTE roaming architecture in an international roaming scenario.
Figure 2 illustrates a typical call flow for a location query when a user equipment is in its home network, in accordance with the existing systems.
Figure 3 illustrates the LTE roaming architecture wherein the VPLMN and the HPLMN are interconnected via international interconnect operator, in accordance with existing systems.
Figure 4 illustrates the network architecture diagram in which the proxy HSS is implemented in accordance with exemplary embodiments of the present invention.
Figure 5 illustrates the system architecture of the proxy HSS, in accordance with exemplary embodiments of the present invention.
Figure 6 illustrates the method of determining a location of an international in-roaming subscriber user equipment, in accordance with exemplary embodiments of the present invention.
Figure 7 illustrates the call flow diagram of determining a location of an international in-roaming subscriber user equipment, in accordance with exemplary embodiments of the present invention.

The foregoing shall be more apparent from the following more detailed description of the disclosure.
DESCRIPTION OF THE INVENTION
In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address all of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein.
The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth.
Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.

Also, it is noted that individual embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional steps not included in a figure.
The present invention relates to a method and system for determining a location information of an in-roaming international subscriber user equipment. As described above, when any location query is received, a request is required to be sent to the HSS of the home network to get the address of the serving MME. However, in international roaming, the network operator of the home network does not allow the visited network to query the HSS of the home network. To solve this issue, whenever an in-roamer international subscriber latches to the visited network, and the MME of the visited network performs authentication with the HSS of the home network over the diameter interface, this in-roamer signaling traffic is duplicated at the DEA and sent to the proxy HSS. This data includes at least the Mobile Station International Subscriber Directory Number (MSISDN) of the in-roamer international subscriber user equipment as well as the Fully Qualified Domain Name (FQDN) of the current serving MME. The proxy HSS maintains this data dynamically such that it always has the updated information of the current serving MME of all the in-roamer international subscriber user equipment. Thereafter, all location queries can thus be routed to the proxy HSS at the visited network itself which returns the current serving MME address, wherein the current serving MME address can be used to query the serving MME for the current location of the user equipment. Thus, the location services are not required to communicate with the home HSS to retrieve the address of the serving MME and location information of the user equipment.

Figure 4 illustrates the network architecture diagram in which the proxy HSS is implemented in accordance with exemplary embodiments of the present invention. As shown in Fig. 4, a home network or HPLMN [401] includes a Home Subscriber Server [402] which is connected to a Diameter Routing Agent (DRA) [404] of the International Interconnect operator’s network [403]. The DRA [404] is further connected to one or more Diameter Edge Agents (DEA) [406(1), 406(2), etc. collectively referred to as 406] of the serving operator’s network or the VPLMN [419]. The DEAs [406] are connected to the VoLTE network [408] as well as the proxy Home Subscriber Server (proxy HSS) [414]. The Location Services platform (LCS) [418] are connected to the proxy HSS [414] via a DRA [416]. Further, the VoLTE network comprises one or more eNodeB [410] and MME (such as [420]). The in-roaming international subscriber user equipment [412(1), 412(2)… 412A] latches on to a MME in the VPLMN [419]. In this description, all the international in-roamer subscriber user equipment are numbered as [412] collectively; while the international in-roamer subscriber user equipment for which a location query is received is numbered as [412A] only for the purpose of clarity.
The home network [401] is the network to which the user equipment [412] is originally registered. The HSS [402] stores all the user subscription information of all user equipment that are subscribers of the home network [401]. This user subscription information or subscriber data includes the International Mobile Subscriber Identity (IMSI) and Mobile Subscriber ISDN Number (MSISDN) of the subscriber UEs. The subscriber data may also include user profile information such as service subscription states and user-subscribed Quality of Service information. The HSS [402] is also configured to generate security information for Mutual network-terminal authentication and Radio path ciphering and integrity protection. The HSS [402] performs other functions as already known to a person skilled in the art and described by the technical specifications. Due to the sensitivity of the information in the HSS [402], the home network operator

does not allow any visited network operator to query the HSS [402].
The International Interconnect operator’s network [403] is an interconnect network that connects the home network [401] to the visited network [419]. The Diameter Routing Agent (DRA) [404] is a routing entity that helps in routing traffic between the home network [401] and the visited network [419]. More specifically, the DRA [404] routes traffic/ signaling between the HSS [402] and the DEAs [406]. The DRA [404] may also perform other functions such as load balancing, routing certain messages to specific nodes in the network, etc.
As shown, the serving operator network or visited network [419] includes one or more DEAs [406] that are configured to connect the visited network [419] with the International interconnect network [403]. The DEAs [406] enable communication with the International interconnect network [403] over a single connection. The DEAs [406] may also implement other functions like topology hiding to ensure that the network elements of the visited network [419] and the addressed thereof are not exposed to the International interconnect network [403].
The DEAs [406] are also configured to receive the location update message/s exchanged between a serving MME and the home HSS [402] for one or more international in-roaming subscriber user equipment [412], and duplicate the same. The DEAs [406] are also configured to transmit the dynamically duplicated location update message/s to the proxy HSS [414].
The visited network [419] comprises of the LTE network [408], further comprising elements such as Enhanced Packet Core (EPC) including Mobility Management Entity (MME), Home Subscriber Server (HSS), Serving gateway, Packet data network (PDN) gateway, Policy and Charging Rules Function (PCRF), etc. Such elements are not shown in the Figure for the sake of clarity. The HSS and gateways as mentioned in this paragraph pertain to the Visited network and must not be confused with the HSS [402] of the home network. The EPC of the

LTE network [408] is connected to E-UTRAN comprising one or more eNodeB [410(1), 410(2), 410(3), etc.]. The eNodeB communicate directly and wirelessly with the in-roamer international subscriber user equipment [412].
As used herein, the user equipment or user device refer to any electrical, electronic and computing device that is capable of communicating wirelessly and perform standard cellular operations. The user equipment may include but is not limited to a mobile phone, a smartphone, personal digital assistant, tablet computer, general-purpose computer, wearable devices such as smartwatches, or any other electronic or computing device as may be obvious to a person skilled in the art.
The proxy HSS [414] is connected to the one or more DEAs [406]. The proxy HSS [414] receives from the DEAs [406], location update message/s exchanged between the serving Mobility Management Entity (MME) and a Home Subscriber Server (HSS) [402] for one or more international in-roaming subscriber user equipment. The location update messages include Update Location Request (ULR) messages and an Update Location Answer (ULA) messages.
The proxy HSS [414] is further configured to process said received location update message/s to determine a current attach status of said one or more international in-roaming subscriber user equipment [412]; and stores said determined current attach status of said one or more international in-roaming subscriber user equipment [412].
Further, the proxy HSS [414] is configured to receive from the location server [418] via the Diameter Routing Agent (DRA) [416], a location query for a first international in-roaming subscriber user equipment [412A]. The proxy HSS [414] processes the location query to determine a serving MME address of said first international in-roaming subscriber user equipment [412A] based on said stored current attach status. The proxy HSS [414] is also configured to transmit said determined serving MME address to the location server [418], wherein the

location of the first international in-roaming subscriber user equipment [412A] is determined using said serving MME address. The detailed architecture and functionality of the proxy HSS [414] is described with reference to Fig. 5.
The location server [418] is configured to receive requests for determining a location of a user equipment from one or more sources such as third-party application servers, emergency service server, other network elements, lawful intercept client, etc. The location server [418] is configured to receive such requests, service requests and send back responses to the requests. The location server [418] is configured to implement the positioning functionality in a cellular network. In the present invention, the location server [418] is configured to route the location service requests via the DRA [416] to the proxy HSS [414] so as to retrieve the current serving MME address. The location server [416] also hosts a number of functionalities or interface to functionalities like portal server, app server, notification client, provisioning server, Identity management server, ad server, etc.
Although Fig. 4 shows an implementation of the invention in an LTE network, however, it will be appreciated by those skilled in the art that the same is done for exemplary purposes only. The invention encompasses to be implemented in any other networks such as the GSM network, 5G network, etc. Further, although only a few DEAs [406(1) and 406(2)] have been shown in Fig. 4, it will be appreciated by those skilled in the art that the invention encompasses lesser or more number of DEAs [406] based on the traffic in the serving operator network [419]. Further, the DEAs [406] may be dynamically added or removed based on the traffic conditions in the visited network [419].
Figure 5 illustrates the system architecture of the proxy HSS, in accordance with exemplary embodiments of the present invention. As shown in Fig. 5, the proxy HSS [414] comprises at least of a transceiver unit [502], a processing unit [504] and a memory unit [506], all components connected to each other. The

transceiver unit [502] comprises a combined radio receiver and transmitter and also a switch that connects the radio receiver and transmitter to an antenna (components not shown in the figure). The transceiver unit [502] may be operated in half-duplex mode (i.e. transmitter and receiver operate on same frequency) or full-duplex mode (i.e. transmitter and receiver operate on different frequencies). The transceiver unit [502] is configured to receiving dynamically from a Diameter Edge Agent (DEA) [406], at least one location update message exchanged between a serving Mobility Management Entity (MME) and a Home Subscriber Server (HSS) [402] for one or more international in-roaming subscriber user equipment.
The transceiver unit [502] is further configured to receive from a location server [418] via a Diameter Routing Agent (DRA) [416], a location query for a first international in-roaming subscriber user equipment [412A]. Further, the transceiver unit [502] is also configured to transmit to the location server [418], said determined serving MME address, wherein the location of the first international in-roaming subscriber user equipment [412A] is determined using said serving MME address.
The processing unit [504] comprises of one or more processors. As used herein, a “processor” or “processing unit” includes one or more processors, wherein processor refers to any logic circuitry for processing instructions. A processor may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor, a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits, Field Programmable Gate Array circuits, any other type of integrated circuits, etc. The processor may perform signal coding data processing, input/output processing, and/or any other functionality that enables the working of the system according to the present disclosure. More specifically, the processor or processing unit is a hardware processor.

The processor unit [504] is configured to receive the location update message from the transceiver unit [502] and process the same to determine a current attach status of said one or more international in-roaming subscriber user equipment [412]. The processing unit [504] is further configured to receive location query from the transceiver unit [502] and process said location query to determine a serving MME address of said first international in-roaming subscriber user equipment [412A] based on said stored current attach status.
The memory unit [506] is configured to receive data from the transceiver unit [502] as well as from the processing unit [504]. As used herein, “memory unit” refers to a machine or computer-readable medium including any mechanism for storing information in a form readable by a computer or similar machine. For example, a computer-readable medium includes read-only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory devices or other types of machine-accessible storage media.
More specifically, the memory unit [506] is configured to store said determined current attach status of said one or more international in-roaming subscriber user equipment [412(1), 412(2), etc.]. The current attach status comprises an International Mobile Subscriber Entity (IMSI) of said one or more international in-roaming subscriber user equipment [412], a Mobile Station International Subscriber Directory Number (MSISDN) of said one or more international in-roaming subscriber user equipment [412], a serving MME fully qualified domain name (FQDN) and a last attach timestamp of said one or more international in-roaming subscriber user equipment [412]. The memory unit [506] may store this information in the form of a table or a database. For instance, data may be stored in the memory unit [412] in the following format:

MSISDN IMSI FQDN of current serving MME Registration Timestamp
123456789 082967203634923126 xxx 01:34;22112019
234567890 082967203634923127 yyy 12:42;21112019
… … … …
… … … …
Table 1
The memory unit [506] is configured to store the updated information of each UE connected to the visited network [219]. The memory unit [506] therefore stores a dedicated database for the international in-roamer subscriber user equipment.
Figure 6 illustrates the method of determining the location of an international in-roaming subscriber user equipment, in accordance with exemplary embodiments of the present invention. The method begins at step [602] wherein the proxy Home Subscriber Server (proxy HSS) [414] receives dynamically, from a Diameter Edge Agent (DEA) [406], at least one location update message exchanged between a serving Mobility Management Entity (MME) and a Home Subscriber Server (HSS) [402] for one or more international in-roaming subscriber user equipment [412]. As discussed the above paragraphs, whenever a location update message such as an Update Location Request (ULR) message and an Update Location Answer (ULA) message, is exchanged between the MME [420] and the HSS [402], a copy of the same is transmitted by the DEA [406] to the proxy HSS [414]. Thus, this location update messages are received at the proxy HSS [414] in real-time and dynamically with minimal or no delay. Further, the invention encompasses establishing a connection between said proxy HSS [414]

and said DEA [406] over a diameter interface.
The ULR message may additionally comprise of a Session-Id, Vendor-Specific-Application-Id, Auth-Session-State, Origin-Host, Origin-Realm, Destination-Host, Destination-Realm, Username, Supported-Features, Terminal-Information, RAT-Type, ULR-Flags, Visited-PLMN-Id, SGSN-Number, etc. The ULA message may additionally comprise of Session-Id, Vendor-Specific-Application-Id, Result-Code, Experimental-Result, Auth-Session-State, Origin-Host, Origin-Realm, Supported-Features, ULA-Flags, Subscription-Data, AVP, Failed-AVP, Proxy-Info, Route-Record, etc.
Next, at step [604], said received at least one location update message is processed by the proxy HSS [414] to determine a current attach status of said one or more international in-roaming subscriber user equipment [412]. This processing of said received at least one location update message to determine the current attach status of said one or more international in-roaming subscriber user equipment [412] comprises extracting from said location update message at least one of an International Mobile Subscriber Entity (IMSI) of said one or more international in-roaming subscriber user equipment [412], a Mobile Station International Subscriber Directory Number (MSISDN) of said one or more international in-roaming subscriber user equipment [412], a serving MME fully qualified domain name (FQDN) and a last attach timestamp of said one or more international in-roaming subscriber user equipment [412]. This extracted information indicates the current attach status of the one or more international in-roaming subscriber user equipment [412] since it provides the current serving MME address, i.e. the FQDN of the MME that is currently serving the user equipment [412] or to which the user equipment [412] is latched.
Thereafter, at step [606], said determined current attach status of said one or more international in-roaming subscriber user equipment [412] are stored at the proxy HSS [414]. As indicated above, this information on the current attach

status of said one or more international in-roaming subscriber user equipment [412] may be stored in the form of a database or table as indicated in an exemplary table 1 above.
Subsequently, at step [608], a location query for said first international in-roaming subscriber user equipment [412] is received at the proxy HSS [414] from a location server [418] via a Diameter Routing Agent (DRA) [416]. This location query may be received at the location server [418] from a third-party application, emergency service server, lawful intercept client, etc. The location query pertains to a specific first user equipment [412A] whose location is desired to be determined.
At step [610], this location query is processed by the proxy HSS [414] to determine a serving MME address of said first international in-roaming subscriber user equipment [412] based on said stored current attach status. Processing of this location query includes identifying/ extracting the IMSI and/or MSISDN of the first user equipment [412A]. Thereafter, this extracted IMSI/ MSISDN of the first international in-roaming subscriber user equipment [412A] is searched in the stored database and a corresponding current attach status of the first user equipment [412A] is identified. Lastly, the serving MME address corresponding to said identified IMSI/MSISDN of said first international in-roaming subscriber user equipment [412A] is identified from the stored current attach status.
Lastly, at step [612] the proxy HSS [414] transmits said determined serving MME address to the location server [418], using which the location of the first international in-roaming subscriber user equipment [412A] is determined. Thereafter the method terminates.
By way of an example, say, one or more international in-roamer user equipment [412(1), 412(2)] visit the serving operator visited network [419] and latch on to the LTE network [408] via one or more MME. Another first user equipment

[412A] that is also an international in-roamer user equipment latches on to the LTE network [408] via the MME [420]. Thus, MME [420] is the current serving MME of the first user equipment [412A]. Within the LTE network [408], any user equipment [412] may switch from one MME to another within the network [408]. During this switching, the MME sends a location update message, i.e. ULR to the HSS [402] via DEA [406]. This ULR message is duplicated by the DEA [406] and sent to the proxy HSS [414], where the message is processed and the IMSI, MSISDN, FQDN of the serving MME [420] and the timestamp is stored. Say for instance, for the user equipment 412(1), 412(2) and 412(A) are stored as follows in Table 2:

UE MSISDN IMSI FQDN of current serving MME Registration Timestamp
412(1) 1234567890 082967203634923126 xxx 01:34;22112019
412(2) 2345678901 082967203634923127 yyy 12:42;22112019
… … … …
412(A) 3456789012 082967203634923128 abcd 10:40;22112019
Table 2
Now, say a request for determining a location of a first user equipment [412A] is received at the location server [418]. This request is sent by the location server [418] to the proxy HSS [414]. From this request, the proxy HSS [414] extracts the MSISDN and IMSI of the first user equipment [412A], i.e. 3456789012 and 082967203634923128 respectively. Thereafter, the proxy HSS [414] looks up in the stored table for this MSISDN and IMSI of the first user equipment [412A] and

identifies the address of the current serving MME [420] from the last row as extracted below in Table 2.1.

412(A) 3456789012 082967203634923128 abcd 10:40;22112019
Thus, the MME address identified by the proxy HSS [414] is “abcd”.
Thereafter the proxy HSS [414] transmits the MME [420] address back to the Location Server [418]. The Location Server [418] now queries the specified/identified MME for the location of the first user equipment[412A]. The MME [420] upon receiving this request, queries the ESMLC [708] for location information and upon receipt of the same, the MME [420] transmits this location information of the first user equipment [412A] back to the location server [418]. In this manner, the current location of the first user equipment [412A] is determined without querying the HSS [402] of the home network [401].
Figure 7 illustrates the call flow diagram of determining a location of an international in-roaming subscriber user equipment, in accordance with exemplary embodiments of the present invention. As shown, the method call flow begins at step 7A, wherein an in-roamer international subscriber user equipment [412A] registers itself in the visitor network [419]. Subsequently, at step 7B, ULA/ULR messages are exchanged between the HSS [402] of the home network [401] and the serving MME [420]. At step 7C, these messages are duplicated by the DEA [406] and transmitted to the proxy HSS [414]. At step 7D, the messages are processed by the proxy HSS [414] and a current attach status of the user equipment [412A] is determined and subsequently stored therein. At step 7E, a location query request is received at the GMLC [706], wherein said GMLC [706] is located in the location server [418].
Next, at step 7F, the location request is routed to the proxy HSS [414] via the DRA [404]. At step 7G, the proxy HSS [414] sends the MME address back to the

GMLC [706]. Thereafter, the GMLC [706] sends a request for subscriber location to the serving MME [420] at step 7H.
Subsequently, at step 7I the MME [420] sends the location request to the ESMLC [708] that calculates the current location of the UE [412] using any positioning procedure and sends back the location information to the serving MME [420] at step 7K. At step 7L, the ESMLC transmits this location information to the GMLC [706] which provides it to the requesting LI Client [704] at step 7M. Thereafter the method terminates.
Thus, as evident from the above disclosure, the deployment of proxy HSS [414] at the visited network [419] helps in easy determination of the location information of the in-roamer international subscriber user equipment [412A] without having the need to query the HSS [402] of the home network [401] for such location information.
The interface, module, memory, database, processor and component depicted in the figures and described herein may be present in the form of a hardware, a software and a combination thereof. The connection shown between these components/module/interface in the proxy HSS [414] is exemplary and any components/module/interface in the proxy HSS [414] may interact with each other through various logical links and/or physical links. Further, the components/module/interface may be connected in other possible ways.
Though a limited number of module, memory, database, processor and other components have been shown in the figures, however, it will be appreciated by those skilled in the art that the overall system of the present invention encompasses any number and varied types of these entities/elements.
While considerable emphasis has been placed herein on the disclosed embodiments, it will be appreciated that many embodiments can be made and that many changes can be made to the embodiments without departing from the principles of the present invention. These and other changes in the embodiments

of the present invention will be apparent to those skilled in the art, whereby it is to be understood that the foregoing descriptive matter to be implemented is illustrative and non-limiting.

We Claim:
1. A method of determining a location of a first international in-roaming subscriber user equipment [412A], the method comprising:
- receiving dynamically, at a proxy Home Subscriber Server (proxy HSS) [414] from a Diameter Edge Agent (DEA) [406], at least one location update message exchanged between a serving Mobility Management Entity (MME) [420] and a Home Subscriber Server (HSS) [402] for one or more international in-roaming subscriber user equipment [412];
- processing, by the proxy HSS [414], said received at least one location update message to determine a current attach status of said one or more international in-roaming subscriber user equipment [412];
- storing, at the proxy HSS [414], said determined current attach status of said one or more international in-roaming subscriber user equipment [412];
- receiving, at the proxy HSS [414] from a location server [418] via a Diameter Routing Agent (DRA) [416], a location query for said first international in-roaming subscriber user equipment [412A];
- processing, by the proxy HSS [414], said location query to determine a serving MME address of said first international in-roaming subscriber user equipment [412A] based on said stored current attach status; and
- transmitting, by the proxy HSS [414] to the location server [418], said determined serving MME address, wherein the location of the first international in-roaming subscriber user equipment [412A] is determined using said serving MME address.

2. The method as claimed in claim 1, wherein said location update message is at least one of an Update Location Request (ULR) message and an Update Location Answer (ULA) message.
3. The method as claimed in claim 1, wherein processing, by the proxy HSS [414], said received at least one location update message to determine the current attach status of said one or more international in-roaming subscriber user equipment [412] comprises extracting from said location update message at least one of an International Mobile Subscriber Entity (IMSI) of said one or more international in-roaming subscriber user equipment [412], a Mobile Station International Subscriber Directory Number (MSISDN) of said one or more international in-roaming subscriber user equipment [412], a serving MME fully qualified domain name (FQDN) and a last attach timestamp.
4. The method as claimed in claim 1, wherein processing, by the proxy HSS [414], said location query to determine the serving MME address comprises:

- extracting, by the proxy HSS [414] from the location query, an International Mobile Subscriber Entity (IMSI) of said first international in-roaming subscriber user equipment [412A];
- identifying said IMSI of said first international in-roaming subscriber user equipment [412A] in the stored current attach status of one or more user equipment [412]; and
- identifying the serving MME address corresponding to said identified IMSI of said first international in-roaming subscriber user equipment [412A] in the stored current attach status.
5. A proxy Home Subscriber Server (HSS) [414] to determine a location of a
first international in-roaming subscriber user equipment [412A], the

proxy HSS [414] comprising:
- a transceiver unit [502] configured to receiving dynamically from a Diameter Edge Agent (DEA) [406], at least one location update message exchanged between a serving Mobility Management Entity (MME) [420] and a Home Subscriber Server (HSS) [402] for one or more international in-roaming subscriber user equipment [412];
- a processing unit [504] connected to said transceiver unit [502], said processing unit [504]configured to process said received at least one location update message to determine a current attach status of said one or more international in-roaming subscriber user equipment [412]; and
- a memory unit [506] connected to said transceiver unit [502] and said processing unit [504], the memory unit [506] configured to store said determined current attach status of said one or more international in-roaming subscriber user equipment [412],
wherein said transceiver unit [502] is further configured to receive from a location server [418] via a Diameter Routing Agent (DRA) [416], a location query for said first international in-roaming subscriber user equipment [412A],
wherein the processing unit [504] is further configured to process said location query to determine a serving MME address of said first international in-roaming subscriber user equipment [412A] based on said stored current attach status,
wherein the transceiver unit [502] is further configured to transmit to the location server [418], said determined serving MME address, wherein the location of the first international in-roaming subscriber user equipment

[412A] is determined using said serving MME address.
6. A method of determining a location of a first international in-roaming subscriber user equipment [412A], the method comprising:
- Receiving, at a Diameter Edge Agent (DEA) [406], at least one location update message exchanged between a serving MME [420] and a home HSS [402] for one or more international in-roaming subscriber user equipment [412];
- duplicating, by the DEA [406], said received at least one location update message;
- dynamically transmitting, by the DEA [406] to a proxy HSS [414], said duplicated at least one location update message;
- Processing, by the proxy HSS [414], said received duplicated at least one location update message to determine a current attach status of said one or more international in-roaming subscriber user equipment [412];
- storing, at the proxy HSS [414], said determined current attach status of said one or more international in-roaming subscriber user equipment [412];
- receiving, at a location server [418], a location query for said first international in-roaming subscriber user equipment [412A];
- transmitting, by the location server [418] to the proxy HSS [414] via a DRA [404], said location query;
- processing, by the proxy HSS [414], said location query to determine a serving MME address of said first international in-roaming subscriber user equipment [412A] based on said stored current attach status;

- transmitting, by the proxy HSS [414] to the location server [418], said determined serving MME address; and
- retrieving, by the location server [418] from said serving MME [420], the location of the first international in-roaming subscriber user equipment [412A].
7. The method as claimed in claim 6 further comprising establishing a connection between said proxy HSS [414] and said DEA [406] over a diameter interface.