For the purposes of the present document, the terms given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905. eMTC NB-IoT RedCap

In the 5G era, various IoT technologies [2] [3] [4] [5] such as eMTC, NB-IoT, and RedCap have been developed to fulfil the increasing demand from verticals. These IoT technologies have achieved low cost, low power and massive connections and can meet requirements of many applications. However, there are still some use cases and applications that can benefit from an IoT technology that requires less power and has lower cost than previous IoT technologies. Improvements can be made where maintenance-free devices are required (e.g. where the devices are inaccessible and it is not possible to replace the device battery) or for devices in extreme environmental conditions. Finally, ultra-low complexity, very small device size/form factor (e.g. thickness of mm), longer life cycle, etc. are required for some use cases. Ambient IoT is a technology to fulfil these market requirements. This Technical Specification describes the Ambient IoT technology service requirements as part of the 5G system to enable new services and use cases. Ambient IoT has the potential to benefit a large number of vertical industries, e.g. smart manufacturing, logistics and warehousing, smart grid, agriculture, and smart home by providing functionalities that fulfil the needs of industrial use cases. Therefore, a new kind of IoT service for the vertical industries will be enabled by combining Ambient IoT with cellular networks, vastly benefitting the 3GPP ecosystem.

Not all Ambient IoT devices are the same. Nevertheless, Ambient IoT devices have the following characteristics.

• Energy harvesting: An Ambient IoT device is an IoT device powered by energy harvesting, being either battery-less or with limited energy storage capability (e.g. using a capacitor). Energy is provided through harvesting of radio waves, light, motion, heat, or any other suitable power source. Energy harvesting can be continuous or incidental (e.g. based on the vibration that a vibration sensor has to report). It cannot be assumed that Ambient IoT devices always have enough power to initiate or receive communication.
• Low complexity: Ambient IoT devices are expected to have lower complexity, smaller size, reduced capabilities and lower power consumption than previously defined 3GPP IoT devices (e.g. NB-IoT/eMTC devices). Low complexity of Ambient IoT devices is also expected to be reflected in efficient use of network resources. In general, Ambient IoT applications will deploy very large numbers of Ambient IoT devices.
• Low data rates: Generally, Ambient IoT data transmissions contain only a low amount of data.
• Life span: Ambient IoT devices can be maintenance free and can have long life span (e.g. more than 10 years). However, the life span of an Ambient IoT device can also be relatively short, e.g. when tracking a package through a logistics chain.
• Communication characteristics: Ambient IoT devices can have a variety of communication characteristics, different from other IoT devices, based on how the Ambient IoT devices are powered by energy harvesting and whether / how the harvested energy can be stored. Ambient IoT devices will only be able to communicate when they have enough power. This can be an issue, especially when communication is initiated towards the Ambient IoT device, while it is not known whether the Ambient IoT device has enough power to receive this communication. For communications initiated by the Ambient IoT device, the Ambient IoT device cannot transmit data until it has harvested / stored enough energy. Some Ambient IoT devices can be powered on demand when they need to communicate. Additionally, some Ambient IoT devices will be able to communicate on a regular basis and have communication characteristics similar to regular IoT devices.

Ambient IoT can support many different use cases. Nevertheless, in general the Ambient IoT use cases can be characterised in four different use case categories:

• Inventory taking: With inventory taking, the main purpose is to discover what goods (e.g. boxes, containers, packages, tools) are present in a specific area. Upon request sent by the network within the specific area, Ambient IoT devices attached to these goods report an identifier associated with the good, possibly supplemented with other information such as status, measurement results and/or location.
• Sensor data collection: With sensor data collection, the Ambient IoT device is associated with a sensor. Transfer of sensor data can be initiated by the Ambient IoT device, e.g. periodically or when the Ambient IoT device has power, or can be triggered by the network.
• Asset tracking: With asset tracking, the main purpose is to determine the location of goods. Ambient IoT devices attached to these goods report an identifier associated with the good. This can then be combined with location information. Asset tracking can also be initiated by an Ambient IoT capable UE (i.e. a UE that can communicate with an Ambient IoT device), thus finding the location of Ambient IoT devices within a particular range of the UE.
• Actuator control: With actuator control, the Ambient IoT device is associated with an actuator. Transfer of actuator commands is generally initiated by the network.

Ambient IoT devices are expected to be able to communicate with the 5G network and/or Ambient IoT capable UE using the one or more of the following communication modes: Ambient IoT Direct Network Communication: Ambient IoT Indirect Network Communication: Ambient IoT device to UE direct Communication: Figures depicting these communication modes are presented below:

The functional requirement for Ambient IoT service includes 6 aspects, i.e.

• Communication;
• Positioning/location;
• Management;
• Collected information and network capability exposure;
• Charging;
• Security and privacy

The Ambient IoT devices have some special characteristics such as Energy harvesting, Low complexity, Low data rates, Life span, and Reachability, etc. Ambient IoT capable UEs are 3GPP UEs with the capability to communicate with an Ambient IoT device.

Ambient IoT service can be categorized into 4 categories, namely inventory, sensor data collection, tracking and actuator control. The corresponding performance services requirements are listed in the following subclauses.