# US 2020/0396262 A1 · Ims routing based on subscriber type

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- Number: US 2020/0396262 A1
- Document ID: US20200396262A1
- Status: Published application
- Kind: A1
- Application number: 16/442,343
- Filed: 2019-06-14
- Published: 2020-12-17
- Earliest claimed: 2019-06-14
- Assignees: T-Mobile USA, Inc.
- Applicants: T-Mobile USA, Inc.
- Inventors: Mohammed Al-Mehdar; Saqib Badar; Shujaur Mufti; Khurram Ahmad Mirza; Kalyan Kalepu
- Web page: https://patentgrep.com/patent/US20200396262A1

## CPC

- H04L 65/1069: Session establishment or de-establishment
- H04L 61/503: using an authentication, authorisation and accounting [AAA] protocol, e.g. remote authentication dial-in user service [RADIUS] or Diameter
- H04L 65/00: Network arrangements, protocols or services for supporting real-time applications in data packet communication (real-time or near real-time messaging, e.g. instant messaging [IM] H04L51/04; selective video distribution H04N21/00)
- H04L 65/1016: IP multimedia subsystem [IMS]
- H04L 65/1073: Registration or de-registration
- H04L 65/1104: Session initiation protocol [SIP]
- H04M 15/66: {Policy and charging system}
- H04W 8/04: Registration at HLR or HSS [Home Subscriber Server]
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A network operator can partition network elements, including elements of an IP Multimedia Subsystem (IMS) or Policy and Charging Rules Functions (PCRFs) into groups reserved for specific types of subscribers. When a user equipment (UE) registers with an IMS, elements of the IMS can contact a Home Subscriber Server (HSS) to determine a subscriber type associated with the UE. Based on the UE's subscriber type, an IMS element can determine an application server or other IMS element to contact about the UE based on identifying application servers or IMS elements that are also associated with the same subscriber type as the UE. Similarly, an IMS element can determine a PCRF to contact about the UE based on identifying a PCRF that is associated with the same subscriber type as the UE.

## Claims

### Claim 1

A method comprising:
receiving, by a serving call session control function (S-CSCF) of an IP Multimedia Subsystem (IMS), a registration message for a UE during registration of the UE with the IMS;
retrieving, by the S-CSCF, a subscriber type associated with the UE from a Home Subscriber Server (HSS);
generating, by the S-CSCF, a response message that indicates the subscriber type associated with the UE; and
sending, by the S-CSCF, the response message to a proxy call session control function (P-CSCF) associated with the UE.

### Claim 2 (depends on 1)

The method of claim 1, wherein the P-CSCF is configured to select a Policy and Charging Rules Function (PCRF) that is also associated with the subscriber type associated with the UE and to send information about the UE to the PCRF.

### Claim 3 (depends on 1)

The method of claim 1, wherein the S-CSCF receives the subscriber type associated with the UE from the HSS in a Diameter protocol message and wherein the S-CSCF generates the response message as a Session Initiation Protocol (SIP) message.

### Claim 4 (depends on 3)

The method of claim 3, wherein the Diameter protocol message includes the subscriber type in an attribute-value pair, and the SIP message includes the subscriber type in a header field.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
identifying, by the S-CSCF, an application server that is associated with the subscriber type associated with the UE; and
sending, by the S-CSCF, a third-party registration message about the UE to the application server.

### Claim 6 (depends on 5)

The method of claim 5, wherein the third-party registration message identifies the subscriber type associated with the UE to the application server.

### Claim 7 (depends on 1)

The method of claim 1, wherein the subscriber type is selected from at least a first value indicating that a user of the UE subscribes to services of a mobile network operator (MNO) and a second value indicating that the user of the UE subscribes to services of a mobile virtual network operator (MVNO).

### Claim 8 (depends on 1)

The method of claim 1, wherein the subscriber type is selected from at least a first value indicating that a user of the UE subscribes to a first type of subscription plan for Long-Term Evolution (LTE) services and a second value indicating that the user of the UE subscribes to a second type of subscription plan for fifth generation (5G) services.

### Claim 9 (depends on 1)

The method of claim 1, wherein the subscriber type is selected from at least a first value indicating that a user of the UE subscribes to a priority tier subscription plan and a second value indicating that the user of the UE subscribes to a standard tier subscription plan.

### Claim 10

An IP Multimedia Subsystem (IMS) comprising:
a proxy call session control function (P-CSCF) associated with a user equipment (UE); and
a serving call session control function (S-CSCF) configured to:
receive, during registration of the UE with the IMS, a registration message associated with the UE from the P-CSCF;
retrieve a subscriber type associated with the UE from a Home Subscriber Server (HSS);
generate a response message that indicates the subscriber type associated with the UE; and
send the response message to the P-CSCF.

### Claim 11 (depends on 10)

The IMS of claim 10, wherein the P-CSCF is configured to:
identify a plurality of Policy and Charging Rules Functions (PCRFs) that are associated with different subscriber types;
select a PCRF from the plurality of PCRFs that is associated with the subscriber type associated with the UE; and
send information about the UE to the PCRF.

### Claim 12 (depends on 10)

The IMS of claim 10, wherein the S-CSCF is configured to receive the subscriber type associated with the UE from the HSS in a Diameter protocol message and generate the response message as a Session Initiation Protocol (SIP) message.

### Claim 13 (depends on 10)

The IMS of claim 10, wherein the S-CSCF is further configured to:
identify an application server that is associated with the subscriber type associated with the UE; and
send a third-party registration message about the UE to the application server.

### Claim 14 (depends on 10)

The IMS of claim 10, wherein the subscriber type is selected from at least a first value and a second value, the first value and the second value being associated with subscribers to different network operators, subscribers to Long-Term Evolution (LTE) services or fifth generation (5G) services, or subscribers to different tiers of subscription plans.

### Claim 15

A method comprising:
receiving, by a call session control function (CSCF) of an IP Multimedia Subsystem (IMS), a registration message for a UE during registration of the UE with the IMS;
retrieving, by the CSCF, a subscriber type associated with the UE from a Home Subscriber Server (HSS);
identifying, by the CSCF, a next element of the IMS that is also associated with the subscriber type associated with the UE; and
sending, by the CSCF, a message about the UE to the next element.

### Claim 16 (depends on 15)

The method of claim 15, wherein the CSCF is a serving CSCF (S-CSCF), the next element is an application server that is also associated with the subscriber type associated with the UE, and the message is a third-party registration message sent by the S-CSCF to the application server.

### Claim 17 (depends on 16)

The method of claim 16, wherein the third-party registration message identifies the subscriber type associated with the UE to the application server.

### Claim 18 (depends on 15)

The method of claim 15, wherein the CSCF is an interrogating CSCF (I-CSCF), the next element is a serving CSCF (S-CSCF) that is also associated with the subscriber type associated with the UE, and sending the message about the UE to the next element comprises forwarding, by the I-CSCF, the registration message for the UE to the S-CSCF.

### Claim 19 (depends on 15)

The method of claim 15, wherein the subscriber type is selected from at least a first value indicating that a user of the UE subscribes to services of a mobile network operator (MNO) and a second value indicating that the user of the UE subscribes to services of a mobile virtual network operator (MVNO).

### Claim 20 (depends on 15)

The method of claim 15, wherein the subscriber type is selected from at least a first value indicating that a user of the UE subscribes to a first type of subscription plan for Long-Term Evolution (LTE) services and a second value indicating that the user of the UE subscribes to a second type of subscription plan for fifth generation (5G) services.