This brief video and presentation introduces the concept of : Mobile Initiated Connection Only (MICO). This mode is designed for IoT devices that send small amounts of data. MICO mode has to be negotiated between the device and AMF in 5GC. A device in MICO mode cannot be paged as it would not listen to paging to conserve battery power. This extreme power saving mode can ensure that the battery can last for very long time, ideally years thereby making this vision of billions of connected IoT devices a reality. All our #3G4G5G slides and videos are available at: Videos: https://www.youtube.com/3G4G5G Slides: https://www.slideshare.net/3G4GLtd 5G Page: https://www.3g4g.co.uk/5G/ Free Training Videos: https://www.3g4g.co.uk/Training/

1. Mobile Initiated Connection Only
(MICO)
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2. High Level Architecture of M2M/IoT
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Sensor/Machine/Thing
Connectivity
Base Station
Flow of data
Control Information /
Software Updates
Core Network /
Network Server
Backhaul
(Wired / Wireless)

3. Defining Mobile Initiated Connection Only (MICO)
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• MICO is a mode of operation for 5G only devices, connected to 5G Core
(5GC)
• A device can request the AMF to enable MICO mode.
• When a MICO activated device is in an Idle state, the 5G network will
consider the device to be unreachable.
• The device will only receive MT (Mobile Terminated) data when it
transitions to a Connected state.
• This transition to Connected whilst in MICO mode is always triggered
by the mobile.
• The mobile will not be paged whilst in MICO mode.
• MICO does not apply for non-3GPP access

4. The Registration Procedure
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5. Registration Request Message
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6. The Registration Procedure
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7. Registration Accept Message
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8. Registration Accept Message
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9. Registration Accept Message
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10. MICO & Power Saving Enhancements
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(source: 3GPP TS 23.501 V16.4.0 (2020-03))
5.31.7 Power Saving Enhancements
5.31.7.1 General
To enable UE power saving and to enhance MT reachability while using MICO mode, e.g. for CIoT, the following
features are specified in the following clauses:
- Extended Discontinuous Reception (DRX) for CM-IDLE and CM-CONNECTED with RRC-INACTIVE;
- MICO mode with Extended Connected Time;
- MICO mode with Active Time;
- MICO mode and Periodic Registration Timer Control.
If a UE requests via NAS to enable both MICO mode with Active Time and extended idle mode DRX, e.g. based
on local configuration, Expected UE Behaviour, if available, UE requested Active Time value, UE subscription
information and network policies etc, the AMF may decide to enable MICO mode with or without Active Time,
extended idle mode DRX or both.

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12. References
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• 3G4G: 3GPP 5G Specifications (link)
• 3GPP TS 24.501: Non-Access-Stratum (NAS) protocol for 5G System (5GS)
• 3GPP TS 23.501: System architecture for the 5G System (5GS)
• 3GPP TS 23.502: Procedures for the 5G System (5GS)
• Apis: What Does the Word “Reachability” Really Mean in 5G?, Mar 2019 (link)
• Wireless Moves: Connection-, Registration- And Session Management, May
2018 (link)

13. Thank You
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