FORM 2
THE PATENTS ACT, 1970 (39 OF 1970) & THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“METHODS AND SYSTEMS FOR USER EQUIPMENT (UE)
CONTEXT MANAGEMENT DURING AN IDLE MODE
MOBILITY PROCEDURE”
We, Jio Platforms Limited, an Indian National, of Office - 101, Saffron, Nr. Centre Point, Panchwati 5 Rasta, Ambawadi, Ahmedabad - 380006, Gujarat, India.
The following specification particularly describes the invention and the manner in which it is to be performed.

METHODS AND SYSTEMS FOR USER EQUIPMENT (UE) CONTEXT MANAGEMENT DURING AN IDLE MODE MOBILITY PROCEDURE
CROSS-REFERENCE
[0001] The present disclosure takes priority from Indian Patent Application
No. 202321060043 filed on 6th September 2023, and Indian Patent Application No. 202321063926 filed on 22nd September 2023.
FIELD OF THE DISCLOSURE
[0002] Embodiments of the present disclosure generally relate to mobility
management systems in networks. More particularly, embodiments of the present disclosure relate to methods and systems for a user equipment (UE) context management during an idle mode mobility procedure.
BACKGROUND
[0003] The following description of the 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 is used only to enhance the understanding of the reader with respect to the present disclosure, and not as admissions of the prior art.
[0004] Wireless communication technology has rapidly evolved over the past
few decades, with each generation bringing significant improvements and advancements. The first generation of wireless communication technology was based on analog technology and offered only voice services. However, with the advent of the second generation (2G) technology, digital communication and data

services became possible, and text messaging was introduced. The third generation (3G) technology marked the introduction of high-speed internet access, mobile video calling, and location-based services. The fourth generation (4G) technology revolutionized wireless communication with faster data speeds, better network coverage, and improved security. Currently, the fifth generation (5G) technology is being deployed, promising even faster data speeds, low latency, and the ability to connect multiple devices simultaneously. With each generation, wireless communication technology has become more advanced, sophisticated, and capable of delivering more services to its users.
[0005] In the 4G communication system, a plurality of network entities (NEs)
is provided, for example a Mobility Management Entity (MME), a Serving Gateway (S-GW), a PDN Gateway (P-GW), a Home Subscriber Server (HSS) and a Policy and Charging Rules Function (PCRF) and the like. One or more of the aforementioned network entities communicates with each other, to implement multiple activities on the 4G communication system. For example, for data transfer, the MME communicates with the SGW, to initiate the communication.
[0006] Similarly, in the 5G communication system, a plurality of network
functions (NFs) is provided, for example an Access and Mobility Management Function (AMF), a session management function (SMF), an Authentication Server function (AUSF), a Network Slice Selection Function (NSSF), a Policy control function (PCF), a Network Repository Function (NRF), a User Plane Function (UPF), a Unified Data Management (UDM) and the like. One or more of the aforementioned NFs communicates with each other, to implement multiple activities on the 5G communication system. For example, for data transfer, the AMF communicates with the SMF, to initiate the communication, which communicates with the UPF.

[0007] As is conventionally known, in a communication network, a user
equipment (UE) remains either in a connected mode or an idle mode. In idle mode, the network reduces usage of resources for saving power consumption of the UE and network resources processing. In the communication network, the UE may freely move anywhere. For example, the UE may move from one network coverage area such as 5G network coverage area to another network coverage area such as 4G network coverage area. The UE may also move within the same network technology having different control network entities such as moving from 4G to 4G in different regions with different MME entities. When the UE moves from one network coverage area to another network area, the AMF in the 5G network and the MME in the 4G network communicate over an N26 interface in the communication network.
[0008] Further, as may be known, when the UE is serviced by a particular
technology network coverage, the UE goes into the idle mode and then subsequently the UE goes into another technology network coverage, which is known as Idle mode mobility. When the UE is in a network coverage area which provides 4G network coverage, an old-MME temporarily assigns Globally Unique Temporary ID (GUTI) to the UE. Similarly, when the UE is in the service area of 5G network coverage, the AMF temporarily assigns GUTI to the UE.
[0009] But in the instant case the GUTI assigned by the AMF or the old-MME
is received in a Tracking Area Update (TAU) request, which is received from RAN/UE. However, this creates difficulty to select a correct instance of a process, a service group, an MME process, or a thread for further service access. It is difficult for MME modules to decode the information associated with the correct GUTI assigned by the AMF/old MME. Further, in the case of 5G-4G Idle mode mobility procedure, there is no identity available in the TAU request received from RAN/UE, which creates difficulty to select the correct process/MME process and/or the thread for further service access.

[0010] Thus, there exists an imperative need in the art to provide an efficient
system and method for designing MME in a way that maintains the user IMSI to Process/Thread affinity, during the period for which the UE is attached at MME. Further, there is a need for an architecture that helps in avoiding multiple race condition scenarios and also reduces lock contention. Also, there exists a need for a solution which optimises the CPU resource usage and provides a stable architecture. Furthermore, there is a need to maintain user context, at the process/services group/ MME PROCESS that is serving that particular user. There exists a need for avoiding scattering of context to multiple process/service groups and providing an efficient user context management.
SUMMARY
[0011] This section is provided to introduce certain aspects of the present
disclosure in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
[0012] An aspect of the present disclosure may relate to a method for a user
equipment (UE) context management during an idle mode mobility procedure. The method comprises receiving, by a transceiver unit, at a new mobility management entity (MME), a tracking area update (TAU) request from the UE. The method further comprises sending, by the transceiver unit, from the new MME, a context request to an access and mobility management function (AMF) based on the TAU request. The method further comprises receiving, by the transceiver unit, at the new MME, a context response from the AMF, wherein the context response comprises a user identifier associated with the UE. The method further comprises determining, by a determination unit, at the new MME, an old MME process of the UE based on the received context response. The method further comprises sending, by the

transceiver unit, from the new MME, a context acknowledgement to the AMF. The method further comprises handling, by a processing unit, at an old MME, the idle mode mobility procedure of the UE based on the old MME process.
[0013] In an exemplary aspect of the present disclosure, the idle mode mobility
is from 5G communication network to 4G communication network.
[0014] In another exemplary aspect of the present disclosure, the old MME
process is of the 5G communication network, and the new MME process is of the 4G communication network.
[0015] In another exemplary aspect of the present disclosure, the TAU request
is received via an S1 application protocol load balancer (S1AP LB) associated with the new MME.
[0016] In another exemplary aspect of the present disclosure, the new MME
and the AMF communicate over an N26 interface.
[0017] In another exemplary aspect of the present disclosure, the S1AP LB
identifies the TAU request as the 5G communication network to the 4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME.
[0018] In another exemplary aspect of the present disclosure, the user identifier
is an international mobile subscriber identity (IMSI).
[0019] In another exemplary aspect of the present disclosure, for sending the
context acknowledgement upon determining the old MME process, the method further comprises: piggybacking, by the processing unit, at the new MME, a core process transfer message with the context acknowledgement. The method further

comprises sending, by the transceiver unit, from the new MME, the piggybacked core transfer message to a GPRS tunnel protocol load balancer (GTP LB). The method further comprises forwarding, by the transceiver unit, from the GTP LB, the context acknowledgement to the AMF and the core process transfer message to the old MME process.
[0020] In another exemplary aspect of the present disclosure, the old MME
process maintains the user context of the UE comprising at least one of a Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities.
[0021] Another aspect of the present disclosure may relate to a system for user
equipment (UE) context management during an idle mode mobility procedure. The system comprises a transceiver unit, a determination unit, and a processing unit connected with each other. The transceiver unit is configured to receive, at a new mobility management entity (MME), a tracking area update (TAU) request from the UE. The transceiver unit is further configured to send, from the new MME, a context request to an access and mobility function (AMF) based on the TAU request. Further, the transceiver unit is configured to receive, at the new MME, a context response from the AMF, wherein the context response comprises a user identifier associated with the UE. The determination unit is configured to determine, at the new MME, an old MME process of the UE based on the received context response. The transceiver unit further configured to send, from the new MME, a context acknowledgement to the AMF. Further, the processing unit is configured to handle, at an old MME, the idle mode mobility procedure of the UE based on the old MME process.
[0022] Another aspect of the present disclosure may relate to a method for a
user equipment (UE) context management during an idle mode mobility procedure. The method comprises receiving, by a transceiver unit, at a new mobility

management entity (MME), a tracking area update (TAU) request from the UE. The
method further comprises sending, by the transceiver unit, from the new MME, a
context request to an old MME based on the TAU request. The method further
comprises receiving, by the transceiver unit, at the new MME, a context response
5 from the old MME, wherein the context response comprises a user identifier
associated with the UE. The method further comprises determining, by a
determination unit, at the new MME, an old MME process of the UE based on the
received context response. The method further comprises sending, by the
transceiver unit, from the new MME, a context acknowledgement to the old MME.
10 The method further comprises handling, by a processing unit, at the new MME, the
idle mode mobility procedure of the UE based on the old MME process.
[0023] In another exemplary aspect of the present disclosure, the idle mode
mobility procedure is between a first 4G communication network and a second 4G
15 communication network.
[0024] In another exemplary aspect of the present disclosure, the old MME is
of the first 4G communication network and the new MME is of the second 4G communication network. 20
[0025] In another exemplary aspect of the present disclosure, the TAU request
is received via an S1 application protocol load balancer (S1AP LB) associated with the new MME.
25 [0026] In another exemplary aspect of the present disclosure, the new MME
and the old MME communicate over an S10 interface.
[0027] In another exemplary aspect of the present disclosure, the S1AP LB
identifies the TAU request as the first 4G communication network to the second 4G
8

communication network idle mode mobility, prior to forwarding the TAU request to the new MME.
[0028] In another exemplary aspect of the present disclosure, the user identifier
5 is an international mobile subscriber identity (IMSI).
[0029] In another exemplary aspect of the present disclosure, for sending the
context acknowledgement upon determining the old MME process, the method comprises piggybacking, by the processing unit, at the new MME, a core process
10 transfer message with the context acknowledgement. The method further comprises
sending, by the transceiver unit, from the new MME, the piggybacked core transfer message to a GPRS tunnel protocol load balancer (GTP LB). The method further comprises forwarding, by the transceiver unit, from the GTP LB, the context acknowledgement to the old MME and the core process transfer message to the old
15 MME process.
[0030] In another exemplary aspect of the present disclosure, the old MME
process maintains the user context of the UE comprising at least one of a Protocol
data Unit (PDU) session context, a security key, mobility restriction list, UE radio
20 capability and UE security capabilities.
[0031] Another aspect of the present disclosure may relate to a system for a
user equipment (UE) context management during an idle mode mobility procedure. The system comprises a transceiver unit, a determination unit, and a processing unit
25 connected to each other. The transceiver unit is configured to receive, at a new
mobility management entity (MME), a tracking area update (TAU) request from the UE. The transceiver unit is further configured to send, from the new MME, a context request to an old MME based on the TAU request. The transceiver unit is further configured to receive, at the new MME, a context response from the old
30 MME, wherein the context response comprises a user identifier associated with the
9

UE. Further, the determination unit is configured to determine, at the new MME,
an old MME process of the user based on the received context response. The
transceiver unit is further configured to send, from the new MME, a context
acknowledgement to the old MME; The processing unit is configured to handle, at
5 the new MME, the idle mode mobility procedure of the UE based on the old MME
process.
[0032] Yet another aspect of the present disclosure may relate to a non-
transitory computer readable storage medium storing one or more instructions for
10 user equipment (UE) context management during the idle mode mobility procedure,
the one or more instructions include executable code which, when executed by one or more units of a system, causes the one or more units to perform certain functions. The one or more instructions when executed causes a transceiver unit of the system to receive, at a new mobility management entity (MME), a tracking area update
15 (TAU) request from the UE. The one or more instructions when executed further
causes the transceiver unit of the system to send, from the new MME, a context request to an access and mobility function (AMF) based on the TAU request. The one or more instructions when executed further causes the transceiver unit of the system to receive, at the new MME, a context response from the AMF, wherein the
20 context response comprises a user identifier associated with the UE. The one or
more instructions when executed further causes a determination unit of the system to determine, at the new MME, an old MME process of the UE based on the received context response. The one or more instructions when executed further causes the transceiver unit of the system to send, from the new MME, a context
25 acknowledgement to the AMF. The one or more instructions when executed further
causes a processing unit of the system to handle, at an old MME, the idle mode mobility procedure of the UE based on the old MME process.
[0033] Yet another aspect of the present disclosure may relate to another non-
30 transitory computer readable storage medium storing one or more instructions for
user equipment (UE) context management during the idle mode mobility procedure,
10

the one or more instructions include executable code which, when executed by one
or more units of a system, causes the one or more units to perform certain functions.
The one or more instructions when executed causes a transceiver unit of the system
to receive, at a new mobility management entity (MME), a tracking area update
5 (TAU) request from the UE. The one or more instructions when executed further
causes the transceiver unit of the system to send, from the new MME, a context request to an old MME based on the TAU request. The one or more instructions when executed further causes the transceiver unit of the system to receive, at the new MME, a context response from the old MME, wherein the context response
10 comprises a user identifier associated with the UE. The one or more instructions
when executed further causes a determination unit of the system to determine, at the new MME, an old MME process of the user based on the received context response. The one or more instructions when executed further causes the transceiver unit of the system to send, from the new MME, a context acknowledgement to the
15 old MME. The one or more instructions when executed further causes a processing
unit of the system to handle, at the new MME, the idle mode mobility procedure of the UE based on the old MME process.
OBJECTS OF THE DISCLOSURE
20
[0034] Some of the objects of the present disclosure, which at least one
embodiment disclosed herein satisfies are listed herein below.
[0035] It is an object of the present disclosure to provide a system and a method
25 for a user equipment (UE) context management during an idle mode mobility
procedure.
[0036] It is another object of the present disclosure to provide a system and a
method for maintaining process/thread and IMSI affinity during 5G-4G Idle mode
30 mobility procedure.
11

[0037] It is another object of the present disclosure to provide a system and a
method for maintaining process/thread and IMSI affinity during 4G-4G Idle mode mobility procedure. 5
[0038] It is another object of the present disclosure to provide a system and a
method for maintaining process/thread and IMSI affinity during Idle mode TAU with MME change procedure.
10 [0039] It is another object of the present disclosure to provide a system and a
method for efficient MME design and UE context management which retains Idle mode mobility procedure without affecting the standard procedure message flow.
BRIEF DESCRIPTION OF THE DRAWINGS
15
[0040] 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
20 necessarily to scale, emphasis instead being placed upon clearly illustrating the
principles of the present disclosure. Also, the embodiments shown in the figures are not to be construed as limiting the disclosure, but the possible variants of the method and system according to the disclosure are illustrated herein to highlight the advantages of the disclosure. It will be appreciated by those skilled in the art that
25 disclosure of such drawings includes disclosure of electrical components or
circuitry commonly used to implement such components.
[0041] FIG. 1 illustrates an exemplary block diagram representation of a
system architecture for a data session between 4G and 5G in a communication
30 network, in accordance with exemplary embodiments of the present disclosure.
12

[0042] FIG. 2 illustrates an exemplary block diagram of a computing device
upon which the features of the present disclosure may be implemented, in accordance with exemplary implementation of the present disclosure. 5
[0043] FIG. 3 illustrates an exemplary block diagram of a system for a user
equipment (UE) context management during an idle mode mobility procedure, in accordance with exemplary implementations of the present disclosure.
10 [0044] FIG. 4 illustrates a flow diagram of a method for a user equipment (UE)
context management during an idle mode mobility procedure, in accordance with exemplary implementations of the present disclosure.
[0045] FIG. 5 illustrates another method flow diagram for a user equipment
15 (UE) context management during an idle mode mobility procedure, in accordance
with exemplary implementations of the present disclosure.
[0046] FIG. 6 illustrates an exemplary block diagram of MME system diagram,
in accordance with exemplary embodiments of the present disclosure. 20
[0047] FIG. 7 illustrates an exemplary block diagram of AMF system diagram,
in accordance with exemplary embodiments of the present disclosure.
[0048] The foregoing shall be more apparent from the following more detailed
25 description of the disclosure.
DETAILED DESCRIPTION
13

[0049] 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
5 details. Several features described hereafter may each be used independently of one
another or with any combination of other features. An individual feature may not address any of the problems discussed above or might address only some of the problems discussed above.
10 [0050] 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
15 function and arrangement of elements without departing from the spirit and scope
of the disclosure as set forth.
[0051] Specific details are given in the following description to provide a
thorough understanding of the embodiments. However, it will be understood by one
20 of ordinary skill in the art that the embodiments may be practiced without these
specific details. For example, circuits, systems, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail.
25 [0052] It should be noted that the terms "first", "second", "primary",
"secondary", "target" and the like, herein do not denote any order, ranking, quantity, or importance, but rather are used to distinguish one element from another.
[0053] Also, it is noted that individual embodiments may be described as a
30 process which is depicted as a flowchart, a flow diagram, a data flow diagram, a
14

structure diagram, or a block diagram. Although a flowchart may describe the
operations as a sequential process, many of the operations may 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
5 steps not included in a figure.
[0054] The word “exemplary” and/or “demonstrative” is used herein to mean
serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any
10 aspect or design described herein as “exemplary” and/or “demonstrative” is not
necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,” and other similar words are used in either the detailed
15 description or the claims, such terms are intended to be inclusive—in a manner
similar to the term “comprising” as an open transition word—without precluding any additional or other elements.
[0055] As used herein, a “processing unit” or “processor” or “operating
20 processor” 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 Digital Signal Processing (DSP) core, a controller, a
25 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
30 processor.
15

[0056] As used herein, “a user equipment”, “a user device”, “a smart-user-
device”, “a smart-device”, “an electronic device”, “a mobile device”, “a handheld
device”, “a wireless communication device”, “a mobile communication device”, “a
5 communication device” may be any electrical, electronic and/or computing device
or equipment, capable of implementing the features of the present disclosure. The
user equipment/device may include, but is not limited to, a mobile phone, smart
phone, laptop, a general-purpose computer, desktop, personal digital assistant,
tablet computer, wearable device or any other computing device which is capable
10 of implementing the features of the present disclosure. Also, the user device may
contain at least one input means configured to receive an input from unit(s) which are required to implement the features of the present disclosure.
[0057] As used herein, “storage unit” or “memory unit” refers to a machine or
15 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. The storage unit stores at least the data
20 that may be required by one or more units of the system to perform their respective
functions.
[0058] As used herein “interface” or “user interface” refers to a shared
boundary across which two or more separate components of a system exchange
25 information or data. The interface may also refer to a set of rules or protocols that
define communication or interaction of one or more modules or one or more units with each other, which also includes the methods, functions, or procedures that may be called.
16

[0059] All modules, units, components used herein, unless explicitly excluded
herein, may be software modules or hardware processors, the processors being a
general-purpose processor, a special purpose processor, a conventional processor, a
digital signal processor (DSP), a plurality of microprocessors, one or more
5 microprocessors in association with a DSP core, a controller, a microcontroller,
Application Specific Integrated Circuits (ASIC), Field Programmable Gate Array circuits (FPGA), any other type of integrated circuits, etc.
[0060] As used herein the transceiver unit includes at least one receiver and at
10 least one transmitter configured respectively for receiving and transmitting data,
signals, information or a combination thereof between units/components within the system and/or connected with the system.
[0061] As discussed in the background section, the current known solutions
15 have several shortcomings. The present disclosure aims to overcome the above-
mentioned and other existing problems in this field of technology by providing a method and a system of a user equipment (UE) context management during an idle mode mobility procedure.
20 [0062] FIG. 1 illustrates an exemplary block diagram representation of a
system architecture [100] for a data session between 4G and 5G in a communication network, in accordance with exemplary implementation of the present disclosure. As shown in FIG. 1, the system architecture [100] includes a user equipment (UE) [102], an evolved universal terrestrial radio access network (E-UTRAN) [104], a
25 Mobility Management Entity (MME) [106], a serving gateway (SGW) [108], a next
generation-radio access network (NG-RAN) [110], an access and mobility management function (AMF) [112].
17

[0063] The E- UTRAN [104] may refer to an architecture of one or more base
stations providing the E-UTRA user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE [102].
5 [0064] The MME [106] is a 4G network process responsible for managing
mobility and session management aspects, such as UE registration, connection, and
reachability. It also handles mobility management procedures like handovers and
paging. In implementations of the present disclosure, MME process may refer to
one or more functions of the MME, such as without limitations, initial attachment
10 of the UE [102]; performing a tracking area update (TAU) operation, by generating
TAU requests; managing security of the UE using cryptographic tools like encryption, security key, etc.; and managing one or more sessions of the UE, such as voice calls, data transfer, media streaming, etc.
15 [0065] The SGW [108] is a component of evolved packet core architecture and
is responsible for routing user data between the base stations and the packet data network gateway (PGW), and also coordinates with the MME [106].
[0066] The NG-RAN [110] is the radio access network that provides the
20 wireless connectivity between the user equipment (UE) [102] and a 5G core (5GC)
network. It consists of radio base stations and the radio access technologies that enable wireless communication.
[0067] The Access and Mobility Management Function (AMF) [112] is a 5G
25 core network function responsible for managing access and mobility aspects, such
as UE registration, connection, and reachability. It also handles mobility management procedures like handovers and paging.
[0068] The system architecture [100] further comprises a user plane function
30 (UPF) and a packet data network gateway user plane function (PGW-U) [114]. The
18

UPF is a network function responsible for handling user data traffic, including
packet routing, forwarding, and QoS enforcement. The PGW-U is the component
responsible for providing an interface between the LTE network and other packet
data networks, such as the Internet or SIP-based IMS networks. The PGW-U is
5 made based on the control and user plane separation principles for evolved packet
core (EPC) nodes.
[0069] The system architecture [100] further comprises a Session Management
Function (SMF) and a packet data network gateway control plane function (PGW-
10 C) [116]. Session Management Function (SMF) is a 5G core network function
responsible for managing session-related aspects, such as establishing, modifying,
and releasing sessions. It coordinates with the User Plane Function (UPF) for data
forwarding and handles IP address allocation and QoS enforcement. The PGW-C is
the component responsible for controlling the functions performed by the PGW-U.
15 The PGW-C is made based on the control and user plane separation principles for
EPC nodes.
[0070] The system architecture [100] further comprises a Policy Control
Function (PCF) and a Policy and Charging Rule Function (PCRF) [118]. Policy
20 Control Function (PCF) is a network function responsible for policy control
decisions, such as QoS, charging, and access control, based on subscriber information and network policies. The PCRF (Policy Control and Charging Rules Function) is a functional element that encompasses policy control decision and flow-based charging control functionalities.
25
[0071] The system architecture [100] further comprises a home subscriber
server (HSS) and a Unified Data Management (UDM) [120]. The HSS is the master database for a given subscriber, acting as a central repository of information for network nodes. The UDM is a component responsible to control network user data
30 which may be split into the Authentication Server Function (AUSF) and the UDM.
19

[0072] The system architecture [100] further comprises a Serving GPRS
Support Node (SGSN) [122]. The SGSN [122] is the node that is serving the UE or the mobile station for performing security functions and access control. 5
[0073] Further, the system architecture [100] comprises various interfaces
enabling communication between various components. These various interfaces
may be an N1 interface, an N2 interface, an N3 interface, an N8 interface, an N10
interface, an N11 interface, an N15 interface, an N26 interface, an S1-MME
10 interface, an S1-U interface, an S3 interface, an S4 interface, an S5-U interface, an
S5-C interface, an S6 interface, and an S11 interface.
[0074] The N1 interface may refer to an interface responsible for providing
communication between the AMF [112] and the UE [102]. The N2 interface may
15 refer to an interface responsible for providing communication between the AMF
[112] and the NG-RAN [110]. The N3 interface may refer to an interface responsible for providing communication between the NG-RAN [110] and the UPF + PGW-U [114]. The N8 interface may refer to an interface responsible for providing communication between the AMF [112] and the HSS + UDM [120]. The
20 N10 interface may refer to an interface responsible for providing communication
between the SMF + PGW-C [116] and the HSS + UDM [120]. The N11 interface may refer to an interface responsible for providing communication between the AMF [112] and the SMF + PGW-C [116]. The N15 interface may refer to an interface responsible for providing communication between the AMF [112] and the
25 PCF + PCRF [118].
[0075] The N26 interface may refer to an interface responsible for providing
communication between the AMF [112] and the MME [106]. The N26 interface is
an inter-CN interface between the MME and 5GS AMF in order to enable
30 interworking between EPC and the NG core. Support of the N26 interface in the
20

network is optional for interworking. N26 supports a subset of the functionalities (essential for interworking) that are supported over S10.
[0076] The S1-MME interface may refer to an interface responsible for
5 providing communication between the E-UTRAN [104] and the MME [106]. The
S1-U interface may refer to an interface responsible for providing communication between the E-UTRAN [104] and the SGW [108]. The S3 interface may refer to an interface responsible for providing communication between the SGSN [122] and the MME [106]. The S4 interface may refer to an interface responsible for providing
10 communication between the SGSN [122] and the SGW [108]. The S5-U interface
may refer to an interface responsible for providing communication between the SGW [108] and the UPF + PGW-U [114]. The S5-C interface may refer to an interface responsible for providing communication between the SMF + PGW-C [116] and the SGW [108]. The S6a interface may refer to an interface responsible
15 for providing communication between the HSS + UDM [120] and the MME [106].
The S11 interface may refer to an interface responsible for providing communication between the MME [106] and the SGW [108].
[0077] It may be noted that all the components of the FIG. 1 are assumed to be
20 connected to each other in a manner as obvious to the person skilled in the art for
implementing features of the present disclosure.
[0078] FIG. 2 illustrates an exemplary block diagram of a computing device
[200] upon which the features of the present disclosure may be implemented, in
25 accordance with exemplary implementation of the present disclosure. In an
implementation, the computing device [200] may also implement a method for a user equipment (UE) context management during an idle mode mobility procedure utilising the system [300]. In another implementation, the computing device [200] itself implements the method for the UE context management during the idle mode
30 mobility procedure using one or more units configured within the computing device
21

[200], wherein said one or more units are capable of implementing the features as disclosed in the present disclosure.
[0079] The computing device [200] may include a bus [202] or other
5 communication mechanism for communicating information, and a hardware
processor [204] coupled with bus [202] for processing information. The hardware
processor [204] may be, for example, a general-purpose microprocessor. The
computing device [200] may also include a main memory [206], such as a random-
access memory (RAM), or other dynamic storage device, coupled to the bus [202]
10 for storing information and instructions to be executed by the processor [204]. The
main memory [206] also may be used for storing temporary variables or other
intermediate information during execution of the instructions to be executed by the
processor [204]. Such instructions, when stored in non-transitory storage media
accessible to the processor [204], render the computing device [200] into a special-
15 purpose machine that is customized to perform the operations specified in the
instructions. The computing device [200] further includes a read only memory
(ROM) [208] or other static storage device coupled to the bus [202] for storing static
information and instructions for the processor [204].
20 [0080] A storage device [210], such as a magnetic disk, optical disk, or solid-
state drive is provided and coupled to the bus [202] for storing information and instructions. The computing device [200] may be coupled via the bus [202] to a display [212], such as a cathode ray tube (CRT), Liquid crystal Display (LCD), Light Emitting Diode (LED) display, Organic LED (OLED) display, etc. for
25 displaying information to a computer user. An input device [214], including
alphanumeric and other keys, touch screen input means, etc. may be coupled to the bus [202] for communicating information and command selections to the processor [204]. Another type of user input device may be a cursor controller [216], such as a mouse, a trackball, or cursor direction keys, for communicating direction
30 information and command selections to the processor [204], and for controlling
cursor movement on the display [212]. The input device typically has two degrees
22

of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allow the device to specify positions in a plane.
[0081] The computing device [200] may implement the techniques described
5 herein using customized hard-wired logic, one or more ASICs or FPGAs, firmware
and/or program logic which in combination with the computing device [200] causes or programs the computing device [200] to be a special-purpose machine. According to one implementation, the techniques herein are performed by the computing device [200] in response to the processor [204] executing one or more
10 sequences of one or more instructions contained in the main memory [206]. Such
instructions may be read into the main memory [206] from another storage medium, such as the storage device [210]. Execution of the sequences of instructions contained in the main memory [206] causes the processor [204] to perform the process steps described herein. In alternative implementations of the present
15 disclosure, hard-wired circuitry may be used in place of or in combination with
software instructions.
[0082] The computing device [200] also may include a communication
interface [218] coupled to the bus [202]. The communication interface [218]
20 provides a two-way data communication coupling to a network link [220] that is
connected to a local network [222]. For example, the communication interface [218] may be an integrated services digital network (ISDN) card, cable modem, satellite modem, or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, the communication
25 interface [218] may be a local area network (LAN) card to provide a data
communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, the communication interface [218] sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.
30
23

[0083] The computing device [200] can send messages and receive data,
including program code, through the network(s), the network link [220] and the
communication interface [218]. In the Internet example, a server [230] might
transmit a requested code for an application program through the Internet [228], the
5 ISP [226], the local network [222], a host [224] and the communication interface
[218]. The received code may be executed by the processor [204] as it is received, and/or stored in the storage device [210], or other non-volatile storage for later execution.
10 [0084] Referring to FIG. 3, an exemplary block diagram of a system [300] for
a user equipment (UE) context management during an idle mode mobility procedure, is shown, in accordance with the exemplary implementations of the present disclosure. The system [300] comprises at least one transceiver unit [302], at least one determination unit [304], and at least one processing unit [306]. Also,
15 all of the components/ units of the system [300] are assumed to be connected to
each other unless otherwise indicated below. As shown in FIG. 3, all units shown within the system [300] should also be assumed to be connected to each other. Also, in FIG. 3, only a few units are shown; however, the system [300] may comprise multiple such units or the system [300] may comprise any such numbers of said
20 units, as required to implement the features of the present disclosure. Further, in an
implementation, the system [300] may be present in the UE [102] to implement the features of the present disclosure. The system [300] may be a part of the UE [102] or may be independent of but in communication with the UE [102]. In another implementation, the system [300] may reside in a server or a network entity. In yet
25 another implementation, the system [300] may reside partly in the server/ network
entity and partly in the UE [102].
[0085] The system [300] is configured for the UE context management during
the idle mode mobility procedure, with the help of the interconnection between the
30 components/units of the system [300].
24

[0086] As may be known, the UE Context management is a function that
allows the AMF [112] or the MME [106] to establish, modify or release a UE
Context in the AMF [112] or the MME [106] and the RAN node and also enables
5 the AMF to manage radio resource control (RRC) state notifications of a CM-
CONNECTED UE. Further, the idle mode mobility procedure may for example, be
Inter-RAT idle mode mobility between NB-IoT and WB-
EUTRAN/UTRAN/GERAN is supported. Mobility procedure may be defined as a
series of steps undertaken by the MME [106] or the AMF [112] to facilitate
10 handover of the UE [102] from one network to another, or from a node of a network
servicing one area to another node of the network servicing another area that the UE [102] has moved to.
[0087] Idle mode of the UE [102] is a state that the UE [102] may enter during
15 times when activities, such as transmission and/or reception of data is not occurring
in the UE [102. During the idle mode of the UE [102], the UE [102] enters into a low-power state in order to conserve energy.
[0088] For UE context management during idle mode mobility procedure, the
20 transceiver unit [302] receives a tracking area update (TAU) request. It may be
noted that the TAU request may be received at a new mobility management entity
(MME) [106] from the UE [102]. A tracking area update (TAU) may be performed
when a user equipment (such as the UE [102]) enters a new tracking area from an
older tracking area. In an embodiment, the TAU may further occur if the UE [102]
25 enters a tracing area whose identity is not currently registered for the UE [102], by
a network that the UE [102] is moving within. The TAU request may refer to a
request for initiation of TAU procedure by sending a message to the RAN together
with RRC parameters indicating the Selected Network and the old globally unique
MME identifier (GUMMEI) associated with the old MME. In another
30 implementation of the present disclosure, the old MME process may be of the 5G
25

communication network, and the new MME process may be of the 4G communication network.
[0089] In an implementation of the present disclosure, the idle mode mobility
5 procedure is from a 5G communication network to a 4G communication network.
In other words, the idle mode mobility procedure refers to the mobility of the UE [102] from a coverage area of the 5G communication network to another network coverage area of 4G communication network.
10 [0090] Further, in another implementation of the present disclosure, the TAU
request may be received via an S1 application protocol load balancer (S1AP LB) [604] associated with the new MME [106]. It may be noted that the S1AP LB [604] may be a component which acts as a load balancing function to ensure equally loaded MMEs within an MME pool area. In further implementation of the present
15 disclosure, the S1AP LB [604] identifies the TAU request as the 5G communication
network to the 4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME [106].
[0091] On receipt of the TAU request, the transceiver unit [302] then sends a
20 context request based on the TAU request. The context request may be sent from
the new MME [106] to an access and mobility function (AMF) [112]. As may be known, the context request may refer to a request message which is used for initiating the UE context management process for retrieving user information.
25 [0092] In one of the implementations of the present disclosure, the new MME
[106] and the AMF [112] may communicate over an N26 interface. The N26 interface may refer to an interface which interconnects the 5G Core network function AMF with 4G network node MME and enables interworking between 5G to 4G and vice-versa.
30
26

[0093] After the context request is received at the respective entities, then the
transceiver unit [302] receives a context response comprising a user identifier
associated with the UE [102]. Again, it may be noted that the context response may
be received at the new MME [106], from the AMF [112]. The context response may
5 refer to a response message comprising information requested in the context request
used for initiating the UE context management process for retrieving user information.
[0094] In one of the implementations of the present disclosure, the user
10 identifier may be an international mobile subscriber identity (IMSI). As may be
known in the art, the IMSI may refer to an identifier allocated to each mobile subscriber.
[0095] On receipt of the context response from respective entities, then the
15 determination unit [304] determines an old MME process of the UE [102] based on
the received context response. It may be noted that the determination of the old MME process may be done at the new MME [106].
[0096] A routing mechanism is defined for the MMEs that are required to find
20 the correct MME from multiple MMEs that are associated with a pool area. When
a UE roams out of the pool area and into the area of one or more MMEs that do not
know about the internal structure of the pool area where the UE roamed from, a
new MME will send the Context Request message to an old MME using the GUTI.
In such a case, the MME which was already connected with the UE is the old MME,
25 and the new MME is the MME which is required to be connected after roaming/
mobility procedure.
[0097] Thereafter, the transceiver unit [302] sends a context acknowledgement
from the new MME [106] to the AMF [112]. The context acknowledgement may
27

refer to an indication regarding a change in the serving gateway and providing information associated with a selection of a new serving gateway.
[0098] It may be noted that in one of many implementations of the present
5 disclosure, to send the context acknowledgement upon determining the old MME
process, the processing unit [306] piggybacks a core process transfer message with the context acknowledgement. Further, to send the acknowledgement the transceiver unit [302] sends the piggybacked core transfer message to a GPRS tunnel protocol load balancer (GTP LB) [606] (shown in FIG.6). Thereafter the
10 transceiver unit [302] forward from the GTP LB [606], the context
acknowledgement to the AMF [112] and the core process transfer message to the old MME process. A core transfer message is a message exchanged between core nodes in a network, such as the MME, and the AMF, and is used to indicate which gateway or node the UE [102] is to be switched to or attached to. In an example,
15 the core transfer message is used from the old MME [106]to the new MME [106]
(and/or vice versa), and the core transfer message may include an identifier of the old and/or new MME [106], a TAI associated with the old and/or new MME [106]. In another example, the core transfer message is used from the old MME [106] to the AMF [112] (and/or vice versa), and the core transfer message may include an
20 identifier of the old MME [106] and/or the AMF [112], a TAI associated with the
old MME [106] and/or the AMF [112].
[0099] Piggybacking is a process of data transfer between two nodes that
allows multiple streams of data to be exchanged simultaneously between any two
25 nodes. Hence, by piggybacking the transfer message with the context
acknowledgement, any lag or delay in providing mobility to the UE [102] between the old MME [106] and the new MME [106]/or the AMF [112] is significantly reduced.
28

[0100] After the context acknowledgement has been sent, the processing unit
[306] handles the idle mode mobility procedure of the UE [102] based on the old MME process. The processing unit [306] may handle the idle mode mobility procedure at the old MME [106]. 5
[0101] In another implementation of the present disclosure, the old MME
process maintains the user context of the UE [102] comprising at least one of a Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities
10
[0102] In a further implementation of the present disclosure, for UE context
management during idle mode mobility procedure, the transceiver unit [302] receives a tracking area update (TAU) request. It may be noted that the TAU request may be received at a new mobility management entity (MME) [106] from the UE
15 [102]. The TAU request may refer to a request for initiation of TAU procedure by
sending a message to the RAN together with RRC parameters indicating the Selected Network and the old Globally Unique MME Identifier (GUMMEI) associated with the old MME [106]. In another implementation of the present disclosure, the old MME process may be of the 5G communication network, and
20 the new MME process may be of the 4G communication network.
[0103] In an implementation of the present disclosure, the idle mode mobility
procedure may be between a first 4G communication network and a second 4G
communication network. In other words, the idle mode mobility procedure may
25 refer to the mobility of the UE [102] from a coverage area of the 4G communication
network to another coverage area of another 4G communication network.
[0104] In another implementation of the present disclosure, the TAU request is
received via an S1 application protocol load balancer (S1AP LB) [604] associated
30 with the new MME [106]. It may be noted that the S1AP LB [604] may be a
29

component which acts as a load balancing function to ensure equally loaded MMEs within an MME pool area.
[0105] In further implementations of the present disclosure, the S1AP LB [604]
5 may identify the TAU request as the first 4G communication network to the second
4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME [106].
[0106] On receipt of the TAU request, the transceiver unit [302] then sends a
10 context request based on the TAU request. It may be noted that the context request
may be sent from the new MME [106] to the old MME [106]. As may be known, the context request may refer to a request message which is used for initiating the UE context management process for retrieving user information.
15 [0107] In one of the implementations of the present disclosure, the old MME
[106] and old MME process may be of the first 4G communication network, and the new MME [106] may be of the second 4G communication network.
[0108] In one of the implementations of the present disclosure, the new MME
20 [106] and the old MME [106] may communicate over an S10 interface. The S10
interface may refer to an interface which connects one MME from a pool of multiple MMEs with other MMEs from the pool of multiple MMEs.
[0109] After the context request, then the transceiver unit [302] receives a
25 context response which comprises a user identifier associated with the UE [102].
Again, it may be noted that the context response may be received at the new MME [106] from the old MME [106]. The context response may refer to a response message comprising information requested in the context request used for initiating the UE context management process for retrieving user information. 30
30

[0110] It may be noted that in an implementation of the present disclosure, the
user identifier may be an international mobile subscriber identity (IMSI). As may be known in the art, the IMSI may refer to an identifier allocated to each mobile subscriber. 5
[0111] On receipt of the context response from respective entities, then the
determination unit [304] determines an old MME process of the UE [102] based on the received context response. It may be noted that the determination of the old MME process may be done at the new MME [106]. 10
[0112] Thereafter, the transceiver unit [302] sends the context
acknowledgement to the old MME [106].
[0113] A routing mechanism is defined for the MMEs that are required to find
15 the correct MME from multiple MMEs that are associated with a pool area. When
a UE [102] roams out of the pool area and into the area of one or more MMEs that
do not know about the internal structure of the pool area where the UE [102] roamed
from, a new MME [106] will send the Context Request message to an old MME
[106] using the GUTI. In such a case, the MME which was already connected with
20 the UE [102] is the old MME [106], and the new MME [106] is the MME which is
required to be connected after roaming/ mobility procedure.
[0114] In one of the implementations of the present disclosure, to send the
context acknowledgement upon determining the old MME process, the processing
25 unit [306] piggybacks a core process transfer message with the context
acknowledgement. Further, to send the acknowledgement the transceiver unit [302] sends the piggybacked core transfer message to a GPRS tunnel protocol load balancer (GTP LB) [606]. Thereafter the transceiver unit [302] forward from the GTP LB [606], the context acknowledgement to the AMF [112] and the core process
30 transfer message to the old MME process.
31

[0115] After the context acknowledgement has been sent, the processing unit
[306] handles the idle mode mobility procedure of the UE [102] based on the old
MME process. The processing unit [306] may handle the idle mode mobility
5 procedure at the new MME [106].
[0116] In one of the implementations of the present disclosure, the old MME
process maintains the user context of the UE [102] comprising at least one of a
Protocol data Unit (PDU) session context, a security key, mobility restriction list,
10 UE radio capability and UE security capabilities.
[0117] In an implementation, for idle mode mobility from 5GS to EPS, the UE
[102] performs either TAU or Attach procedure with EPS GUTI mapped from 5G-
GUTI sent as old Native GUTI and indicates that it is moving from 5GC. The UE
15 [102] includes in the RRC message a globally Unique MME Identifier (GUMMEI)
mapped from the 5G GUTI and indicates it as a native GUMMEI and should in
addition indicate it as "Mapped from 5G-GUTI". The MME [106] retrieves the UE's
MM and SM context from 5GC. For connected mode mobility from 5GS to EPS,
either inter-system handover or RRC Connection Release with Redirection to E-
20 UTRAN is performed. At inter-system handover, the AMF [116] selects target
MME [106] based on 2 octet TAC format used in the Target ID. During the TAU or
Attach procedure the HSS+UDM cancels any AMF registration associated with the
standard access (but not AMF registration associated with the non-standard access).
However, an AMF [106] that was serving the UE [102] over both standard and non-
25 standard accesses does not consider the UE [102] as deregistered over non 3GPP
access.
[0118] Referring to FIG. 4, an exemplary method flow diagram [400] for the
user equipment (UE) context management during the idle mode mobility procedure,
30 in accordance with exemplary implementations of the present disclosure is shown.
32

In an implementation the method [400] is performed by the system [300]. Further, in an implementation, the system [300] may be present in a server device to implement the features of the present disclosure. Also, as shown in FIG. 4, the method [400] starts at step [402]. 5
[0119] Initially, for user equipment (UE) context management during the idle
mode mobility procedure, the method [400] at step [404] involves receiving, by a transceiver unit [302], at a new mobility management entity (MME) [106], a tracking area update (TAU) request from a UE [102]. 10
[0120] In another implementation of the present disclosure, the old MME
process may be of the 5G communication network, and the new MME process may be of the 4G communication network.
15 [0121] In an implementation of the present disclosure, the idle mode mobility
procedure is from a 5G communication network to a 4G communication network.
[0122] Further, in another implementation of the present disclosure, the TAU
request may be received via an S1 application protocol load balancer (S1AP LB)
20 [604] associated with the new MME [106].
[0123] In further implementation of the present disclosure, the S1AP LB [604]
identifies the TAU request as the 5G communication network to the 4G
communication network idle mode mobility, prior to forwarding the TAU request
25 to the new MME [106].
[0124] At step [406], the method [400] comprises sending, by the transceiver
unit [302], from the new MME [106], a context request to an access and mobility management function (AMF) [112] based on the TAU request.
30
33

[0125] In one of the implementations of the present disclosure, the new MME
[106] and the AMF [112] may communicate over an N26 interface.
[0126] Then at step [408], the method [400] involves receiving, by the
5 transceiver unit [302], at the new MME [106], a context response from the AMF
[112], wherein the context response comprises a user identifier associated with the UE [102].
[0127] In one of the implementations of the present disclosure, the user
10 identifier may be an international mobile subscriber identity (IMSI).
[0128] On receipt of context response, then at step [410], the method [400]
comprises determining, by a determination unit [304], at the new MME [106], an old MME process of the UE [102] based on the received context response. 15
[0129] Thereafter, at step [412], the method [400] involves sending, by the
transceiver unit [302], from the new MME [106], a context acknowledgement to the AMF [112].
20 [0130] It may be noted that for sending the context acknowledgement upon
determining the old MME process, the method [400] may further comprise piggybacking, by the processing unit [306], at the new MME [106], a core process transfer message with the context acknowledgement. Then, for sending the context acknowledgement, the method further involves sending, by the transceiver unit
25 [302], from the new MME [106], the piggybacked core transfer message to a GPRS
tunnel protocol load balancer (GTP LB) [606]. Thereafter, for sending the context acknowledgement, the method [400] further involves forwarding, by the transceiver unit [302], from the GTP LB [606], the context acknowledgement to the AMF [112] and the core process transfer message to the old MME process.
30
34

[0131] After the context acknowledgement has been sent, then at step [414],
the method [400] involves handling, by a processing unit [306], at an old MME [106], the idle mode mobility procedure of the UE [102] based on the old MME process. 5
[0132] In another implementation of the present disclosure, the old MME
process maintains the user context of the UE [102] comprising at least one of a Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities 10
[0133] Thereafter, at step [416], the method [400] is terminated.
[0134] Referring to FIG. 5 another exemplary method flow diagram [500] for
the user equipment (UE) context management during the idle mode mobility
15 procedure, in accordance with exemplary implementations of the present disclosure
is shown. In an implementation the method [500] is performed by the system [300]. Further, in an implementation, the system [300] may be present in a server device to implement the features of the present disclosure. Also, as shown in FIG. 5, the method [500] starts at step [502].
20
[0135] For UE context management during idle mode mobility procedure, the
method [500] at step [504] involves receiving, by a transceiver unit [302], at a new mobility management entity (MME) [106], a tracking area update (TAU) request from the UE [102].
25
[0136] In an implementation of the present disclosure, the idle mode mobility
procedure may be between a first 4G communication network and a second 4G communication network.
35

[0137] In another implementation of the present disclosure, the TAU request is
received via an S1 application protocol load balancer (S1AP LB) [604] associated with the new MME [106].
5 [0138] In further implementations of the present disclosure, the S1AP LB [604]
may identify the TAU request as the first 4G communication network to the second 4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME [106].
10 [0139] Then at step [506], the method [500] involves sending, by the
transceiver unit [302], from the new MME [106], a context request to an old MME [106] based on the TAU request.
[0140] In one of the implementations of the present disclosure, the old MME
15 [106] and old MME process may be of the first 4G communication network, and
the new MME [106] may be of the second 4G communication network.
[0141] In one of the implementations of the present disclosure, the new MME
[106] and the old MME [106] may communicate over an S10 interface.
20
[0142] Continuing further, at step [508], the method [500] comprises
receiving, by the transceiver unit [302], at the new MME [106], a context response from the old MME [106], wherein the context response comprises a user identifier associated with the UE [102].
25
[0143] It may be noted that in an implementation of the present disclosure, the
user identifier may be an international mobile subscriber identity (IMSI).
36

[0144] Thereafter, at step [510], the method [500] comprises determining, by
a determination unit [304], at the new MME [106], an old MME process of the UE [102] based on the received context response.
5 [0145] Then, at step [512], the method [500] comprises sending, by the
transceiver unit [302], from the new MME [106], a context acknowledgement to the old MME [106].
[0146] It may be noted that for sending the context acknowledgement upon
10 determining the old MME process, the method [500] may further comprise
piggybacking, by the processing unit [306], at the new MME [106], a core process
transfer message with the context acknowledgement. Then, for sending the context
acknowledgement, the method [500] further involves sending, by the transceiver
unit [302], from the new MME [106], the piggybacked core transfer message to a
15 GPRS tunnel protocol load balancer (GTP LB) [606]. Thereafter, for sending the
context acknowledgement, the method [500] further involves forwarding, by the transceiver unit [302], from the GTP LB [606], the context acknowledgement to the AMF [112] and the core process transfer message to the old MME process.
20 [0147] Then at step [514], the method [500] involves handling, by a processing
unit [306], at the new MME [106], the idle mode mobility procedure of the UE [102] based on the old MME process.
[0148] In one of the implementations of the present disclosure, the old MME
25 process maintains the user context of the UE [102] comprising at least one of a
Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities.
[0149] Referring to FIG. 6 and FIG. 7, exemplary block diagrams of an MME
30 system diagram and the AMF system diagram, respectively, are provided in
37

accordance with exemplary embodiments of the present disclosure. It may be noted that both of the figures are taken collectively for the purpose of explanation of the implementation provided by the present disclosure in the foregoing description.
5 [0150] A radio access network (RAN) [602] may refer to the network node part
of a mobile telecommunications system that connects one or more user equipment
(UE) [102] to the core network (CN). Further, the RAN [602] may be technology
specific and may function similarly or differently based on the technology of
network communications being used. The RAN [602] may comprise radio base
10 stations and radio access technologies that enable wireless communication such as
E-UTRAN [104] and the NG-RAN [110].
[0151] It may be noted that there may be two cases. There may be a scenario
where for the UE context management during idle mobility procedure the UE
15 mobility is between different technology networks (hereinafter referred to as the
“first case” or “Case 1”). For example, between a 5G communication network and a 4G communication network as illustrated in FIG. 6. Another case may be that for the UE context management during idle mobility procedure there may be a case where the mobility is between the same technology network (hereinafter referred to
20 as the “second case” or “Case 2”). For example, between 4G and another 4G
network as illustrated in FIG. 7. Further, the MME [106] may include one or more core processes, which may be performed by core process modules SG1, SG2…SGn [108-1, 108-2…108-n].
25 [0152] For UE context management during idle mode mobility procedure, the
transceiver unit [302] receives a tracking area update (TAU) request. It may be noted that the TAU request may be received at a new mobility management entity (MME) [106] from the UE [102].
38

[0153] In one implementation of Case 1, the idle mode mobility procedure is
from a 5G communication network to a 4G communication network. However, in one implementation of Case 2, the idle mode mobility procedure is between a first 4G communication network and a second 4G communication network. 5
[0154] It may be noted that in both cases, the TAU request is received via an
S1 application protocol load balancer (S1AP LB) [604] associated with the new MME [106].
10 [0155] However, in case 1, the S1AP LB [604] identifies the TAU request as
the 5G communication network to the 4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME [106]. Further, in case 2, the S1AP LB [604] identifies the TAU request as the first 4G communication network to the second 4G communication network idle mode mobility, prior to
15 forwarding the TAU request to the new MME [106].
[0156] On receipt of the TAU request, the transceiver unit [302] then sends a
context request based on the TAU request. It may be noted that in Case 1, the context
request may be sent from the new MME [106] to an access and mobility function
20 (AMF) [112]. Further, in Case 2, the context request may be sent from the new
MME [106] to an old MME [106].
[0157] In implementation of case 1, the old MME process is of the 5G
communication network, and the new MME process is of the 4G communication
25 network. Further, in implementation of case 2, the old MME [106] and old MME
process is of the first 4G communication network, and the new MME [106] is of the second 4G communication network.
39

[0158] It may be noted that in the implementation of Case 1, the new MME
[106] and the AMF [112] communicate over an N26 interface. However, in Case 2, the new MME [106] and the old MME [106] communicate over an S10 interface.
5 [0159] After the context request is received at the respective entities, then the
transceiver unit [302] receives a context response comprising a user identifier
associated with the UE [102]. Again, it may be noted in case 1, the context request
may be received at the new MME [106], from the AMF [112]. Further, in case 2,
the context response may be received at the new MME [106] from the old MME
10 [106].
[0160] In both implementations of the present disclosure, the user identifier is
an international mobile subscriber identity (IMSI).
15 [0161] On receipt of the context response from respective entities, then the
determination unit [304] determines an old MME process of the UE [102] based on the received context response. It may be noted that the determination of the old MME process may be done at the new MME [106].
20 [0162] Thereafter, in case 1, the transceiver unit [302] sends a context
acknowledgement from the new MME [106] to the AMF [112]. Further, in case 2, the transceiver unit [302] sends the context acknowledgement to the old MME [106].
25 [0163] Further, in both cases, to send the context acknowledgement upon
determining the old MME process, the processing unit [306] piggybacks, a core process transfer message with the context acknowledgement. Further, the transceiver unit [302] sends, the piggybacked core transfer message to a GPRS tunnel protocol load balancer (GTP LB) [606] and then forward, from the GTP LB
40

[606], the context acknowledgement to the old MME [106] and the core process transfer message to the old MME process.
[0164] After the context acknowledgement has been sent, the processing unit
5 [306] handles the idle mode mobility procedure of the UE based on the old MME
process. In Case 1, the processing unit [306] may handle the idle mode mobility procedure at an old MME [106]. In Case 2, the processing unit [306] may handle the idle mode mobility procedure at the new MME [106].
10 [0165] It may be noted that in implementations of both cases, the old MME
process maintains the user context of the UE [102] comprising at least one of a Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities.
15 [0166] The present disclosure further discloses a non-transitory computer
readable storage medium storing one or more instructions for user equipment (UE) context management during the idle mode mobility procedure, the one or more instructions include executable code which, when executed by one or more units of a system [300], causes the one or more units to perform certain functions. The one
20 or more instructions when executed causes a transceiver unit [302] of the system
[300] to receive, at a new mobility management entity (MME) [106], a tracking area update (TAU) request from the UE [102]. The one or more instructions when executed further causes the transceiver unit [302] of the system [300] to send, from the new MME [106], a context request to an access and mobility function (AMF)
25 [112] based on the TAU request. The one or more instructions when executed
further causes the transceiver unit [302] of the system [300] to receive, at the new MME [106], a context response from the AMF [112], wherein the context response comprises a user identifier associated with the UE [102]. The one or more instructions when executed further causes a determination unit [304] of the system
30 [300] to determine, at the new MME [106], an old MME process of the UE [102]
41

based on the received context response. The one or more instructions when
executed further causes the transceiver unit [302] of the system [300] to send, from
the new MME [106], a context acknowledgement to the AMF [112]. The one or
more instructions when executed further causes a processing unit [306] of the
5 system [300] to handle, at an old MME [106], the idle mode mobility procedure of
the UE based on the old MME process.
[0167] The present disclosure further discloses another non-transitory
computer readable storage medium storing one or more instructions for user
10 equipment (UE) context management during the idle mode mobility procedure, the
one or more instructions include executable code which, when executed by one or more units of a system [300], causes the one or more units to perform certain functions. The one or more instructions when executed causes a transceiver unit [302] of the system [300] to receive, at a new mobility management entity (MME)
15 [106], a tracking area update (TAU) request from the UE [102]. The one or more
instructions when executed further causes the transceiver unit [302] of the system [300] to send, from the new MME [106], a context request to an old MME [106] based on the TAU request. The one or more instructions when executed further causes the transceiver unit [302] of the system [300] to receive, at the new MME
20 [106], a context response from the old MME [106], wherein the context response
comprises a user identifier associated with the UE [102]. The one or more instructions when executed further causes a determination unit [304] of the system [300] to determine, at the new MME [106], an old MME process of the user based on the received context response. The one or more instructions when executed
25 further causes the transceiver unit [302] of the system [300] to send, from the new
MME [106], a context acknowledgement to the old MME [106]. The one or more instructions when executed further causes a processing unit [306] of the system [300] to handle, at the new MME [106], the idle mode mobility procedure of the UE [102] based on the old MME process.
30
42

[0168] As is evident from the above, the present disclosure provides a
technically advanced solution for a user equipment (UE) context management
during an idle mode mobility procedure. The present solution provides a
configuration of MME in a way that maintains user IMSI to Process/Thread affinity,
5 during the period the user is attached at the MME. The architecture provided by the
present disclosure helps in avoiding multiple race condition scenarios, and reduces
lock contention. Further, the present solution leads to optimising CPU resource
usage, and provides a stable architecture. Also, by implementing the present
disclosure, the user context is maintained only at the process/ MME process that is
10 serving that particular user. Further, the present disclosure avoids scattering of
context to multiple process/service groups, and hence provides efficient user context management.
[0169] Further, the present solution also addresses the need for authenticating
15 the user at MME-new. The present disclosure provides that the MME sends SM
Command to S1AP LB (after receiving context response from MME-old) and piggyback MME transfer information as well. Accordingly, when SM complete is received from the UE, it is transferred to original MME by S1AP LB, and the rest of the process is handled from the original MME. 20
[0170] While considerable emphasis has been placed herein on the disclosed
implementations, it will be appreciated that many implementations can be made and
that many changes can be made to the implementations without departing from the
principles of the present disclosure. These and other changes in the implementations
25 of the present disclosure 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.
[0171] Further, in accordance with the present disclosure, it is to be
30 acknowledged that the functionality described for the various components/units can
43

be implemented interchangeably. While specific embodiments may disclose a particular functionality of these units for clarity, it is recognized that various configurations and combinations thereof are within the scope of the disclosure. The functionality of specific units as disclosed in the disclosure should not be construed as limiting the scope of the present disclosure. Consequently, alternative arrangements and substitutions of units, provided they achieve the intended functionality described herein, are considered to be encompassed within the scope of the present disclosure.

We Claim:
1. A method [400] for a user equipment (UE) context management during an
idle mode mobility procedure, the method [400] comprising:
- receiving, by a transceiver unit [302], at a new mobility management entity (MME) [106], a tracking area update (TAU) request from a UE [102];
- sending, by the transceiver unit [302], from the new MME [106], a context request to an access and mobility management function (AMF) [112] based on the TAU request;
- receiving, by the transceiver unit [302], at the new MME [106], a context response from the AMF [112], wherein the context response comprises a user identifier associated with the UE [102];
- determining, by a determination unit [304], at the new MME [106], an old MME process of the UE [102] based on the received context response;
- sending, by the transceiver unit [302], from the new MME [106], a context acknowledgement to the AMF [112]; and
- handling, by a processing unit [306], at an old MME [106], the idle mode mobility procedure of the UE [102] based on the old MME process.

2. The method [400] as claimed in claim 1, wherein the idle mode mobility is from 5G communication network to 4G communication network.
3. The method [400] as claimed in claim 2, wherein the old MME process is of the 5G communication network, and the new MME process is of the 4G communication network.

4. The method [400] as claimed in claim 1, wherein the TAU request is received via an S1 application protocol load balancer (S1AP LB) [604] associated with the new MME [106].
5. The method [400] as claimed in claim 1, wherein the new MME [106] and the AMF [112] communicate over an N26 interface.
6. The method [400] as claimed in claim 4, wherein the S1AP LB [604] identifies the TAU request as the 5G communication network to the 4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME [106].
7. The method [400] as claimed in claim 1, wherein the user identifier is an international mobile subscriber identity (IMSI).
8. The method [400] as claimed in claim 1, wherein for sending the context acknowledgement upon determining the old MME process, the method comprises:

- piggybacking, by the processing unit [306], at the new MME [106], a core process transfer message with the context acknowledgement;
- sending, by the transceiver unit [302], from the new MME [106], the piggybacked core transfer message to a GPRS tunnel protocol load balancer (GTP LB [606]); and
- forwarding, by the transceiver unit [302], from the GTP LB [606], the context acknowledgement to the AMF [112] and the core process transfer message to the old MME process.
9. The method [400] as claimed in claim 1, wherein the old MME process
maintains the user context of the UE [102] comprising at least one of a

Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities.
10. A system [300] for a user equipment (UE) context management during an
idle mode mobility procedure, the system [300] comprising:
- a transceiver unit [302], the transceiver unit [302] is configured to:
o receive, at a new mobility management entity (MME) [106], a
tracking area update (TAU) request from a UE [102]; o send, from the new MME [106], a context request to an access
and mobility function (AMF) [112] based on the TAU request;
and o receive, at the new MME [106], a context response from the
AMF [112], wherein the context response comprises a user
identifier associated with the UE [102];
- a determination unit [304] connected at least with the transceiver unit
[302], wherein the determination unit [304] is configured to:
o determine, at the new MME [106], an old MME process of the UE [102] based on the received context response;
- the transceiver unit [302] further configured to:
o send, from the new MME [106], a context acknowledgement to the AMF [112]; and
- a processing unit [306] connected at least with the transceiver unit [302],
wherein the processing unit [306] is configured to:
o handle, at an old MME [106], the idle mode mobility procedure of the UE based on the old MME process.
11. The system [300] as claimed in claim 10, wherein the idle mode mobility
procedure is from a 5G communication network to a 4G communication
network.

12. The system [300] as claimed in claim 11, wherein the old MME process is of the 5G communication network, and the new MME process is of the 4G communication network.
13. The system [300] as claimed in claim 10, wherein the TAU request is received via an S1 application protocol load balancer (S1AP LB) [604] associated with the new MME [106].
14. The system [300] as claimed in claim 10, wherein the new MME [106] and the AMF [112] communicate over an N26 interface.
15. The system [300] as claimed in claim 13, wherein the S1AP LB [604] identifies the TAU request as the 5G communication network to the 4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME [106].
16. The system [300] as claimed in claim 10, wherein the user identifier is an international mobile subscriber identity (IMSI).
17. The system [300] as claimed in claim 10, wherein to send the context acknowledgement upon determining the old MME process, the system [300] comprises:
- the processing unit [306] configured to:
o piggyback, a core process transfer message with the context acknowledgement;
- the transceiver unit [302] configured to:
o send, the piggybacked core transfer message to a GPRS tunnel protocol load balancer (GTP LB) [606]; and

o forward, from the GTP LB [606], the context acknowledgement to the AMF [112] and the core process transfer message to the old MME process.
18. The system [300] as claimed in claim 10, wherein the old MME process maintains the user context of the UE [102] comprising at least one of a Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities.
19. A method [500] for a user equipment (UE) context management during an idle mode mobility procedure, the method comprising:

- receiving, by a transceiver unit [302], at a new mobility management entity (MME) [106], a tracking area update (TAU) request from a UE [102];
- sending, by the transceiver unit [302], from the new MME [106], a context request to an old MME [106] based on the TAU request;
- receiving, by the transceiver unit [302], at the new MME [106], a context response from the old MME [106], wherein the context response comprises a user identifier associated with the UE [102];
- determining, by a determination unit [304], at the new MME [106], an old MME process of the UE [102] based on the received context response;
- sending, by the transceiver unit [302], from the new MME [106], a context acknowledgement to the old MME [106]; and
- handling, by a processing unit [306], at the new MME [106], the idle mode mobility procedure of the UE [102] based on the old MME process.

20. The method [500] as claimed in claim 19, wherein the idle mode mobility procedure is between a first 4G communication network and a second 4G communication network.
21. The method [500] as claimed in claim 20, wherein the old MME [106] is of the first 4G communication network and the new MME [106] is of the second 4G communication network.
22. The method [500] as claimed in claim 19, wherein the TAU request is received via an S1 application protocol load balancer (S1AP LB) [604] associated with the new MME [106].
23. The method [500] as claimed in claim 19, wherein the new MME [106] and the old MME [106] communicate over an S10 interface.
24. The method [500] as claimed in claim 22, wherein the S1AP LB [604] identifies the TAU request as the first 4G communication network to the second 4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME [106].
25. The method [500] as claimed in claim 19, wherein the user identifier is an international mobile subscriber identity (IMSI).
26. The method [500] as claimed in claim 19, wherein sending the context acknowledgement upon determining the old MME process comprises:

- piggybacking, by the processing unit [306], at the new MME [106], a core process transfer message with the context acknowledgement;
- sending, by the transceiver unit [302], from the new MME [106], the piggybacked core transfer message to a GPRS tunnel protocol load balancer (GTP LB) [606]; and

- forwarding, by the transceiver unit [302], from the GTP LB [606], the
context acknowledgement to the old MME [106] and the core process
transfer message to the old MME process.
27. The method [500] as claimed in claim 19, wherein the old MME process maintains the user context of the UE [102] comprising at least one of a Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities.
28. A system [300] for a user equipment (UE) context management during an idle mode mobility procedure, the system comprising:
- a transceiver unit [302], the transceiver unit [302] is configured to:
o receive, at a new mobility management entity (MME) [106], a
tracking area update (TAU) request from a UE; o send, from the new MME [106], a context request to an old
MME [106] based on the TAU request; and o receive, at the new MME [106], a context response from the old
MME [106], wherein the context response comprises a user
identifier associated with the UE [102];
- a determination unit [304] connected at least with the transceiver unit
[302], wherein the determination unit [304] is configured to:
o determine, at the new MME [106], an old MME process of the user based on the received context response; and
- the transceiver unit [302] further configured to:
o send, from the new MME [106], a context acknowledgement to the old MME [106]; and
- a processing unit [306] connected at least with the transceiver unit [302],
wherein the processing unit [306] is configured to:
o handle, at the new MME [106], the idle mode mobility procedure of the UE [102] based on the old MME process.

29. The system [300] as claimed in claim 28, wherein the idle mode mobility procedure is between a first 4G communication network and a second 4G communication network.
30. The system [300] as claimed in claim 29, wherein the old MME [106] and old MME process is of the first 4G communication network, and the new MME [106] is of the second 4G communication network.
31. The system [300] as claimed in claim 28, wherein the TAU request is received via an S1 application protocol load balancer (S1AP LB) associated with the new MME [106].
32. The system [300] as claimed in claim 28, wherein the new MME [106] and the old MME [106] communicate over an S10 interface.
33. The system [300] as claimed in claim 31, wherein the S1AP LB [604] identifies the TAU request as the first 4G communication network to the second 4G communication network idle mode mobility, prior to forwarding the TAU request to the new MME [106].
34. The system [300] as claimed in claim 28, wherein the user identifier is an international mobile subscriber identity (IMSI).
35. The system [300] as claimed in claim 28, wherein to send the context acknowledgement upon determining the old MME process, the system [300] comprises:
- the processing unit [306] configured to:

o piggyback, a core process transfer message with the context
acknowledgement; and - the transceiver unit [302] configured to:
o send, the piggybacked core transfer message to a GPRS tunnel
protocol load balancer (GTP LB) [606]; and o forward, from the GTP LB [606], the context acknowledgement
to the old MME [106] and the core process transfer message to
the old MME process.
36. The system [300] as claimed in claim 28, wherein the old MME process maintains the user context of the UE [102] comprising at least one of a Protocol data Unit (PDU) session context, a security key, mobility restriction list, UE radio capability and UE security capabilities.