Study on Cellular Internet of Things (CIoT) support and evolution for the 5G System (5GS)
This technical report studies and evaluates architecture enhancements to address the following objectives:
Objective I: Enable CIoT/MTC functionalities in 5G CN.
The objective is to study how to support identified CioT/MTC functionalities in 5G CN with potential connectivity to WB-EUTRA (eMTC) and/or NB-IoT for 5GS capable devices.
The following CIoT/MTC functionalities need to be evaluated and studied how to enable them in 5G CN, if needed:
- Equivalent overall functionalities as provided by SCEF for CIoT/MTC.
- Monitoring.
- Small data transmission (infrequent and frequent small data transmission including frequent small data transmission from tracking devices).
- Additional power saving functions unless those are supported for 5G system in Rel-15.
- Non-IP Data Delivery.
- Overload control (as relevant in 5G CN).
- Support of Coverage enhancement including adaptations in 5G CN required to support latencies.
- Equivalent to Group communication and messaging.
- Reliable communication via functionality equivalent to SCEF.
- Inter-RAT mobility support to/from NB-IoT.
- High latency communication.
- Include location services procedures for IoT in 5G location services.
NOTE: Attach without PDN connection and non-IP PDN Connection type is already supported in 5G CN (TS 23.501 [5]).
Ensure that regulatory requirements can be fulfilled at the same level as in EPC.
Objective II: Co-existence and migration from EPC based eMTC/NB-IoT to 5GCN.
Study solutions for coexistence and migration from EPC towards 5G CN for eMTC/NB-IoT.
This objective will study solutions where the same service is offered to some UEs connected to EPC and some UEs connected to 5G CN e.g. using SCEF and equivalent functionalities in 5GCN. Solutions that assume that 5G CN needs to support EPC NAS signaling for legacy IoT devices access are not considered.
Any modifications in the EPC-5GC interworking "baseline" specific to CIOT will also be discussed as part of Objective II.
Objective III: 5G System enhancements to address 5G service requirements (based on TS 22.261 [2] and TR 38.913 [3]).
To study system architecture enhancements to address related service requirements defined in TS 22.261 [2] and RAN requirements defined in TR 38.913 [3] and how to enable them in 5G CN, if needed. At least the following service requirements have been identified:
- Enable the change of association between subscription and address/number of an IoT device within same operator and in between different operators.
- Restricted Registration procedure to allow IoT device provisioning.
Any system implications for the RAN will be coordinated with RAN WGs.
This study is not going to study enhancements to EPC.