LTE, M2M Device Addressing and IMSI

I was made aware of the following statement on the Verizon wireless brochure:

LTE’s inherent support for IPV6 addressing and IMSI-based telephone number identifiers makes mass deployments over LTE more easily achievable. The deployment of large numbers of mobile devices (think tens of thousands) becomes much more feasible because of LTE’s use of 15-digit IMSI telephone number identifiers for large-scale deployments, such as M2M or embedded wireless applications. 3G network technologies were limited by their use of 10-digit telephone number identifiers, which made large-scale deployments more difficult. With LTE, mass deployment of wireless services and applications, such as VoIP, smart metering, vending, and telematics, is now practical.

Now we know about the much touted 50 Billion connections by 2025 of which the majority would be M2M devices. So how are we going to handle the issue of addressing these many devices.

In the earlier presentation here, there was a mention of the direction for the solution as below:

The IMSI structure is as shown above. So depending on how it is used this can help alleviate the number shortage problem. 3GPP TR 23.888 gives the following information:

5.13      Key Issue - MTC Identifiers

5.13.1    Use Case Description

The amount of MTC Devices is expected to become 2 orders of magnitude higher than the amount of devices for human to human communication scenarios. This has to be taken into account for IMSI, IMEI and MSISDN. Regulatory bodies indicate shortages of IMSIs and MSISDNs.

The MTC Feature PS Only in TS 22.368 [2] includes a requirement that PS Only subscriptions shall be possible without an MSISDN. In principle an MSISDN is not used in any of the PS based signalling procedures. However, it will have to be assured that all PS procedures indeed work and subscriptions can be uniquely identified without providing an MSISDN. Furthermore, TS 22.368 [2] specifies that remote MTC Device configuration shall be supported for PS only subscriptions without an MSDISDN assigned. Current remote MTC Device configuration solutions (i.e. Device Management and Over-the-Air configuration) are based on SMS, which assumes the use of MSISDNs. So a solution to support remote MTC Device configuration that does not require the use of MSISDNs is needed.

The identifiers can be categorised into:

-     Internal Identifiers: used within the 3GPP system to identify a UE using a subscription (or the subscription itself e.g. when the UE is not registered).

-     External Identifiers: used from outside the 3GPP system (e.g. at the MTCsp interface), to refer to a UE using a subscription (or the subscription itself e.g. when the UE is not registered).

5.13.2    Required Functionality

-     It shall be possible to uniquely identify the ME.

NOTE 1:   This requirement relates to the ME which is generally identified by the IMEI.

-     It shall be possible to uniquely identify the UE using a subscription or the subscription itself.

NOTE 2:   The two requirements above also apply to human-to-human communications. However, for Machine-Type Communication identifiers will have to be able to cater for a number of identifiers up to two orders of magnitude higher than for human-to-human communications.

-     It shall be possible to use the following identifiers:

1.       IMSI, for internal usage within the 3GPP operator domain, and either

2.       E.164 MSISDN, for usage outside the 3GPP operator domain, or

3.       Unique identifier (e.g. FQDN), other than E.164 MSISDN, for usage outside the 3GPP operator domain.

NOTE 3: Use of IMSI outside the 3GPP operator domain is an operator option (i.e. not subject to standardization)

-     If no (unique or common) MSISDN is assigned to a PS only subscription, the Internal Identifier (IMSI) shall be used as charging identifier.

-     It shall be possible to associate one or more External Identifiers to the same Internal Identifier (e.g. several MSISDNs associated with the same IMSI).

-     Globally unique External Identifiers shall be supported for identifying UEs used for MTC that must be globally reachable (i.e. irrespective of which mobile operator owns the subscription)

-     Operator specific External Identifiers (e.g. based on a private numbering plan) may be supported for identifying UEs used for MTC that have to be reachable only from the operator domain to which they are subscribed.

-     The Internal Identifier shall be globally unique.

-     Remote MTC Device configuration shall still be supported for subscriptions without an MSISDN.

NOTE 4:   Current remote MTC Device configuration solutions (i.e. Device Management and Over-the-Air configuration) are based on SMS, which assumes the use of MSISDNs.

Any more information on this subject, more than welcome.