Cellular communication session management for user equipment (UES) in idle mode

1 . A method comprising:

receiving, by a mobile management entity (MME) and from an evolved-universal mobile telecommunications system (UMTS) terrestrial radio access network) (E-UTRAN) in a fourth generation (4G) network, a handover initiation message utilized to initiate a handover for a user equipment (UE) operating in idle mode;

transmitting, by the MME and to an access and mobility management function (AMF) in a fifth generation (5G) network, a handover request message based on the handover initiation message;

receiving, by the MME and from the AMF, a context request message utilized to request a first fully qualified domain name (FQDN) associated with a packet data network (PDN) gateway (PGW);

performing, by the MME, one or more domain name system (DNS) queries to identify service tag information associated with the PGW, the service tag information indicating whether the PGW supports 5G network compatibility;

determining, by the MME and based on the one or more DNS queries, that the service tag information indicates the PGW is compatible with third generation (3G) and fourth generation (4G) networks but not compatible with the 5G network;

deleting, by the MME and based at least in part on the context request message and the determination that the PGW is not compatible with the 5G network based on the service tag information, first PDN information associated with the first FQDN prior to transmitting a context response message without the first PDN information to prevent the AMF from transmitting unnecessary queries to a network function (NF) repository function (NRF);

transmitting, by the MME and to the AMF, the context response message;

receiving, by the MME and from the AMF, and based on the first PDN information associated with the first FQDN being absent from the context response message, a confirmation message indicating a 5G network PDN connection established by the AMF through an initial setup process instead of a 4G-5G handover process, the 5G network PDN connection being established utilizing second PDN information identified by the AMF, the second PDN information including a second FQDN associated with a session management function (SMF); and

utilizing, by the MME, the 5G network PDN connection to exchange communications with the 5G network.

2 . The method of claim 1 , wherein the 5G network PDN connection is established based on the AMF determining to refrain from transmitting a query message to a network function (NF) repository function (NRF), the AMF determining to refrain from transmitting the query message based on the context response message not including the first PDN information.

3 . The method of claim 1 , wherein the handover initiation message is a 4G-5G handover initiation message, and the handover is a 4G-5G handover, further comprising:

receiving, by the MME and from a mobile switching center (MSC) server in a third generation (3G) network, a third-generation (3G)-4G handover initiation message utilized to initiate a 3G-4G handover from a 3G network to the 4G network; and

transmitting, by the MME and to the PGW, via a serving gateway (SGW), a bearer message to perform the 3G-4G handover based on the handover initiation message, the 4G network being utilized by the UE based on completion of the 3G-4G handover for exchanging communications via an IP multimedia system (IMS) PDN connection.

4 . The method of claim 1 , wherein the context request message includes security related information utilized to register the UE with the 5G network, and wherein transmitting the context response message further comprises transmitting the context response message without the first PDN information, the AMF transmitting the confirmation message based on the AMF refraining from transmitting a query for session management function (SMF) information.

5 . The method of claim 1 , wherein the confirmation message is transmitted by the AMF based on the AMF receiving the context request message, registering the UE, transmitting an initial registration request message including UE information associated with the UE to a unified data management (UDM), and receiving a registration response message from the UDM.

6 . The method of claim 1 , wherein the confirmation message is received from the AMF based on the AMF refraining from configuring a session management function (SMF) as part of the handover based on the handover request message, the AMF determining to refrain from configuring the SMF based on the context response message being received from the MME and without the first PDN information.

7 . The method of claim 1 , wherein the 5G network PDN connection to be utilized by the UE is established based on the AMF ending a 4G session and establishing a 5G session, the 5G session being established based on the PGW being unusable as a session management function (SMF) of the 5G network.

8 . The method of claim 1 , wherein the first PDN information is deleted by the MME.

9 . The method of claim 1 , wherein the first PDN information is deleted based at least in part on the service tag information indicating one or more PGWs being utilized to manage non-5G network communication connections for the UE.

10 . A system comprising:

at least one processor; and

memory storing instructions that, when executed by the at least one processor, cause the at least one processor to perform operations comprising:

transmitting, by a mobile management entity (MME) and to an access and mobility management function (AMF) in a fifth generation (5G) network, a handover request to request a handover for a user equipment (UE);

receiving, by the MME and from the AMF, a context request message utilized to request 5G session management function (SMF) information associated with an SMF;

generating, by the MME, a context response without packet data network (PDN) information and including non-5g network PDN gateway (PGW) identity information stored in the MME, the non-5G network PGW identity information including a fully qualified domain name (FQDN);

receiving, by the MME and from the AMF, a confirmation indicating a 5G network PDN connection usable by the UE to exchange communications via the 5G network, the 5G network PDN connection being established utilizing second PDN information identified by the AMF, the second PDN information including a second FQDN associated with a session management function (SMF);

performing, by the MME, one or more domain name system (DNS) queries to identify service tag information associated with the PGW, the service tag information indicating whether the PGW supports 5G network compatibility;

determining, by the MME and based on the one or more DNS queries, that the service tag information indicates the PGW is compatible with third generation (3G) and fourth generation (4G) networks but not compatible with the 5G network;

deleting, by the MME and based at least in part on the context request message and the determination that the PGW is not compatible with the 5G network based on the service tag information, the PDN information prior to transmitting the context response without the PDN information to prevent the AMF from transmitting unnecessary queries to a network function (NF) repository function (NRF); and

transmitting, by the MME and to the AMF, the context response.

11 . The system of claim 10 , wherein the PDN information is first PDN information, and the operations further comprising:

setting a session information delete flag based at least in part on the confirmation; and

deleting, by the MME, the first PDN information based at least in part on the session information delete flag being set.

12 . The system of claim 10 , wherein generating the context response without the PDN information further comprises storing the PDN information until a confirmation is received from the AMF, the confirmation indicating a 5G network PDN connection established by the AMF.

13 . The system of claim 10 , wherein generating the context response without the PDN information further comprises:

deleting the PDN information; and

setting a session information deleted flag, and

wherein transmitting the context response further comprises transmitting, by the MME and to the AMF, the context response based at least in part on the session information deleted flag being set.

14 . The system of claim 10 , wherein the operations further comprising:

receiving, by the MME and from the AMF, a confirmation indicating a 5G network PDN connection established by the AMF;

setting a session delete flag based at least in part on the confirmation; and

transmitting the session delete flag to a session gateway (SGW), the SGW forwarding the session delete flag to a PGW, the PGW deleting session information based at least in part on the session delete flag, the session information including an international mobile subscriber identity (IMSI) associated with a previous session utilized by the UE.

15 . The system of claim 10 , wherein the operations further comprising:

receiving, by the MME and from the AMF, a confirmation indicating a 5G network PDN connection, the 5G network PDN connection being established based at least in part on the AMF utilizing the context request to determine to refrain from transmitting a query to a network function (NF) repository function (NRF).

16 . The system of claim 10 , the operations further comprising:

utilizing, by the MME and prior to transmitting the handover request, a third generation (3G) network to exchange communications for the UE; and

identifying, by the MME and prior to transmitting the handover request, a handover for the UE and from a 3G network to a fourth generation (4G) network,

wherein a confirmation is transmitted by the AMF based at least in part on the AMF utilizing establishment of a PDN connection to determine to transmit the confirmation, a PGW in the 4G network not being compatible with the 5G network, the 5G network including the SMF.

17 . The system of claim 10 , wherein, prior to the handover request being transmitted, the UE utilizes a third generation (3G) PDN connection including a PGW to exchange communications via a 3G network,

the operations further comprising performing, by the MME and prior to transmitting the handover request, a handover for the UE and from the 3G network to a fourth generation (4G) network, the handover being performed based at least in part on i) a UE context release performed by a NodeB of the 3G network, and ii) a resource allocation performed by an eNodeB of the 4G network, the PDN information being omitted from the context response based at least in part on the PGW being compatible with the 3G network and the 4G network but not the 5G network.

18 . A server comprising:

at least one processor; and

memory storing instructions that, when executed by the at least one processor, cause the at least one processor to perform operations comprising:

transmitting, by a mobile management entity (MME) and to an access and mobility management function (AMF) in a fifth generation (5G) network, a handover request;

receiving, by the MME and from the AMF, a context request message utilized to request first packet data network (PDN) information based at least in part on the handover request;

receiving, by the MME and from the AMF, a confirmation indicating a 5G network PDN connection usable by a user equipment (UE) to exchange communications via the 5G network, the 5G network PDN connection being established utilizing 5G network PDN information, the 5G network PDN information including an FQDN associated with a session management function (SMF);

performing, by the MME, one or more domain name system (DNS) queries to identify service tag information associated with a PGW, the service tag information indicating whether the PGW supports 5G network compatibility;

determining, by the MME and based on the one or more DNS queries, that the service tag information indicates the PGW is compatible with third generation (3G) and fourth generation (4G) networks but not compatible with the 5G network;

deleting, by the MME and based at least in part on the context request message and the determination that the PGW is not compatible with the 5G network based on the service tag information, second PDN information prior to transmitting a context response message without the second PDN information to prevent the AMF from transmitting unnecessary queries to a network function (NF) repository function (NRF); and

transmitting, by the MME and to the AMF, the context response without the second PDN information, the context response being utilized by the AMF to perform an initial setup.

19 . The server of claim 18 , wherein the second PDN information is non-5G network PDN information.

20 . The server of claim 18 , wherein the second PDN information is non-5G network PDN information, and receiving the context request further comprises deleting, by the MME, the non-5G network PDN information.