Section: 6.9.1 Description
Content: The UE (remote UE) can connect to the network directly (direct network connection), connect using another UE as a relay UE (indirect network connection), or connect using both direct and indirect connections. Relay UEs can be used in many different scenarios and verticals (inHome, SmartFarming, SmartFactories, Public Safety and others). In these cases, the use of relays UEs can be used to improve the energy efficiency and coverage of the system. Remote UEs can be anything from simple wearables, such as sensors embedded in clothing, to a more sophisticated wearable UE monitoring biometrics. They can also be non-wearable UEs that communicate in a Personal Area Network such as a set of home appliances (e.g. smart thermostat and entry key), or the electronic UEs in an office setting (e.g. smart printers), or a smart flower pot that can be remotely activated to water the plant. When a remote UE is attempting to establish an indirect network connection, there might be several relay UEs that are available in proximity and supporting selection procedures of an appropriate relay UE among the available relay UEs is needed. Indirect network connection covers the use of relay UEs for connecting a remote UE to the 3GPP network. There can be one or more relay UE(s) (more than one hop) between the network and the remote UE. A ProSe UE-to-UE Relay can also be used to connect two remote Public Safety UEs using direct device connection. There can be one or more ProSe UE-to-UE Relay(s) (more than one hop) between the two remote Public Safety UEs.