Content for  TR 22.861  Word version:  14.1.0

As described in the Smart Wearables and Bio-connectivity related use cases in [2], the Internet of Things will support various connectivity models. The devices can connect with the network directly or connect with the network using another device as a relay UE, or they may be capable of using both types of connections. The devices can range from simple wearables, such as a smart watch or a set of sensors embedded in clothing, to a more sophisticated wearable device monitoring biometrics. They can also be non-wearable devices that communicate in a Personal Area Network such as a set of home appliances (e.g., smart thermostat and entry key), or the electronic devices in an office setting (e.g., smart printers), or a smart flower pot that can be remotely activated to provide water to the plant. The relay UE can access the network using 3GPP or non-3GPP access networks (e.g., WLAN, fixed broadband access). Essentially, one or more of the following connection models will apply for any device. Figure 5.2-1 illustrates the connection models,

• Direct 3GPP connection (e.g., a sensor that communicates with an application server or with another device through 3GPP network)
• Indirect 3GPP connection (e.g., a smart wearable that communicates through a smart phone to the 3GPP network)
• Direct device connection (e.g., a bio metric device that communicates directly with other biometric devices or with a smart phone associated with the same patient).

3GPP and non-3GPP RATs may be supported for connectivity scenarios. 3GPP RAT over licensed band or unlicensed band may be supported for connectivity scenarios.

Various combinations of these connectivity scenarios will also need to be supported, including the following.

• Devices that can switch between a direct 3GPP connection and an indirect 3GPP connection
• Devices that can switch between indirect connection using 3GPP RAT and indirect 3GPP connection using non-3GPP RAT
• Devices that only support a direct device connection (e.g., does not support 3GPP connection)
• Groups of devices that communicate among themselves using a direct device connection, and also through an indirect 3GPP connection to the network through one of the devices (e.g., personal area network, home office network)

An example of a combination connectivity scenario is a Personal Area Network for biometric devices. Figure 5.2-2 illustrates a group of biometric devices that communicate among themselves using a direct device connection and also communicate with a 3GPP network through an indirect 3GPP connection. When used in a hospital setting, the biometric devices may communicate with each other and provide information to local display equipment for doctors and nurses to monitor. However, these biometric devices do not need to operate only in a direct device connection mode. When information needs to be uploaded to a server, for example to update the patient's records, it can be done through a relay UE. In this scenario, the relay UE will need to provide 3GPP connection for multiple devices supporting only direct device connection.

Some additional scenarios might apply when a Personal Area Network of devices (e.g., a person wearing several smart wearables) is in indirect 3GPP connection mode:

• A relayed device (e.g., smart watch) and relay UE can belong to the same subscriber or different subscribers of the same PLMN.
• A relayed device (e.g., smart watch) and relay UE can have subscriptions associated with different PLMNs. This is a roaming case.

In either case, the relay UE needs to determine that the device is authorized for an indirect 3GPP connection before a 3GPP connection is established. Both devices also need to be authenticated with the network before the 3GPP connection is established. In all of the scenarios described above, key aspects for 5G include the following:

• Providing secure communications between the devices using direct device connection and direct or indirect 3GPP connection,
• Taking into consideration QoS when choosing connection mode and RAT,
• Supporting the desired end user services, including real-time voice and data,
• Minimizing power consumption on devices,
• Supporting roaming access to the network, whether the relayed device or a relay UE is roaming,
• Supporting multiple relayed devices behind a relay UE,
• Providing service continuity for devices that switch between an indirect 3GPP connection and a direct 3GPP connection,
• Providing service continuity for devices that switch from one indirect 3GPP connection to another indirect 3GPP connection,
• Ensuring devices using a direct device connection, or using a relay UE for an indirect 3GPP connection, are authorized to do so,
• Providing flexibility in the choice of RAT (e.g., 3GPP RATs, non-3GPP RATs) used by the devices.

In each of the connectivity models, use of different type of access to the network (3GPP and non-3GPP RAT), will imply different types of requirements:

• Some requirements will be specific to devices connecting to the 3GPP system through a 3GPP-RAT
• Some requirements will be specific to devices connecting to the 3GPP system through a non-3GPP RAT
• Some general requirements will apply regardless of the RAT used for the direct device connection or the 3GPP connection.