Evolutions of the Mobile Core Network to support M2M/IoT : LTE-M and NB-IoT

Course outline : The mobile core network evolves in Releases 3GPP R13 and R14 to efficiently support MTC (Machine Type Communication) devices. The result is called cIoT (Cellular Internet of Things) with two variants, LTE-M (LTE for MTC) and NB-IoT (Narrowband IoT) which concern the evolution of the LTE network to support IoT devices. Among these evolutions are:
• AESE (Architecture Enhancements for Services) to expose APIs associated with service capabilities to provide value-added services to external enterprise applications.
• DECOR (Dedicated Core Network) which concerns the use of a dedicated core network in order to provide specific characteristics and functions or in order to isolate specific users such as MTC users.
• PSM (Power Save Mode) and Extended DRX (Extended Discontinuous Reception) to optimize energy consumption by the MTC device and support battery saving.
• HLCom (High Latency Communication) to introduce buffering of MT data, when the device is in a power saving state and unreachable..
• MONTE (Monitoring Enhancements) to monitor various events related to MTC devices.
• GROUP (Group Based Enancements) which includes functionalities to manage groups of MTC devices in the mobile network: message delivery to a group of devices, congestion control of a group of devices, addressing of a group of devices , policy control relating to a group of devices.
• NIDD (Non-IP Data Delivery) to replace the establishment of energy-consuming IP data bearers with an extension of the NAS (Non-Access Stratum) protocol to allow small volumes of data to be transferred to the control plane (The IP protocol stack is no longer needed).
The course objective is to present all of these extensions with the associated architectures/interfaces, the underlying functionalities and the call flows to better understand these functionalities.

1. Evolution of mobile network architecture for MTC communications with service capability exposure functions (AESE)
1.1. Architecture without roaming
1.2. Architecture with roaming (home routed and local breakout)
1.3. Entities of the architecture
1.3.1. SCEF/MTC-IWF
1.3.2. MTC-AAA
1.3.3. IWK-SCEF
1.3.4. SCS/AS
1.3.5. HSS
1.3.6. MME
1.3.7. SMSC
1.3.8. PCRF
1.3.9. RCAF
1.4. Interfaces between the entities of the architecture
2. Dedicated core network for M2M/IoT devices (DECOR, Dedicated core)
2.1. Principles
2.2. Dedicated core architecture
2.3. Assignment of the MME of the dedicated core network
2.3.1. Assignment during Attach
2.3.2. Assignment during handover
2.3.3. Assignment during TAU
2.4. Dedicated SGW/PGW selection function
2.5. Reselection of dedicated core network nodes by the HSS during a charge in a subscription profile
2.6. Dedicated circuit swiched core network architecture and associated functions

3. MTC device trigerring procedure
3.1. Device triggering via T4
3.2. Device triggering via SMS
3.3. Call flows associated with different scenarios

4. Procedure for monitoring events related to MTC devices (MONTE, Monitoring Enhancements)
4.1. Event Types
4.1.1. Loss of connectivity
4.1.2. EU reachability
4.1.3. Location Report
4.1.4. Change of IMSI-IMEI association
4.1.5. Roaming status
4.1.6. Communication failure
4.1.7. Availability after DDN (Downlink Data Notification) failure
4.1.8. Number of UEs present in a geographical area
4.2. Monitoring types
4.2.1. Event monitoring via HSS
4.2.2. Event monitoring via MME
4.2.4. Event monitoring via PCRF
4.2.5. Event monitoring via GMLC
4.2.6. Event monitoring via RCAF
4.3. Call flows for the monitoring/notification of events via the different entities

5. MTC device group management procedure (GROUP, Group Enhancements)
5.1. Mobile network optimizations for MTC device groups
5.2. Group-based messaging
5.3. Policy control for groups of MTC devices
5.4. Groups and group identifiers

6. Extended DRX, PSM and HLCom
6.1. Extended idle mode DRX (eDRX) for reduced UE power consumption
6.1.1. Principles of Extended idle mode DRX
6.1.3. Paging for extended idle mode DRX with E-UTRAN
6.2. Power save mode (PSM) for UE power consumption reduction
6.3. High latency communication (HLCom) and Extended DRX
6.3.1. Approach based on extensive buffering of data traffic entering the Serving GW
6.3.2. Approach based on the event monitoring procedure where the events are either UE Reachability or Availability after DDN failure.

7. Options for data connectivity
7.1. IP on User-plane with or without user-plane optimization
7.2. IP on control plane with or without control-plane optimization
7.3. Non-IP on control plane with or without control-plane optimization

8. Delivery of Non-IP Data
8.1. NIDD approach (NIDD, Non-IP Data Delivery)
8.1.1. Establishment of T6a/T6b connection between MME and SCEF
8.1.2. NIDD Setup
8.1.3. NIDD procedure for incoming traffic
8.1.4. NIDD procedure for outgoing traffic
8.1.5. Release of the T6a/T6b connection between MME and SCEF
8.1.6. Modification of the T6a/T6b connection due to MME change
8.1.7. Establishment/Modification/release of the T6a/T6b connection in roaming situation via the IWK-SCEF entity
8.1.8. NIDD charging
8.2. Small data: Transfer of data via NAS without eRAB and reuse of the GTP-U network tunnel between SGW and PGW
8.2.1. Outgoing small data traffic
8.2.2. Incoming small data traffic

10. Conclusion