WO2024002472A1

WO2024002472A1 - State switching for passive terminal device

Info

Publication number: WO2024002472A1
Application number: PCT/EP2022/067879
Authority: WO
Inventors: Oana-Elena Barbu; Benny Vejlgaard
Original assignee: Nokia Technologies Oy
Priority date: 2022-06-29
Filing date: 2022-06-29
Publication date: 2024-01-04

Abstract

Disclosed is a method comprising receiving, by an apparatus in a radio access network, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching, by the apparatus, to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

Description

STATE SWITCHING FOR PASSIVE TERMINAL DEVICE

FIELD

The following example embodiments relate to wireless communication.

BACKGROUND

In the passive internet of things, there may be passive terminal devices that are not equipped with a battery or other power source. There is a challenge in how such passive terminal devices can obtain energy and communicate over long distances.

BRIEF DESCRIPTION

The scope of protection sought for various example embodiments is set out by the independent claims. The example embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments.

According to an aspect, there is provided an apparatus in a radio access network, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: receive, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switch to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided an apparatus in a radio access network, the apparatus comprising means for: receiving, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a method comprising: receiving, by an apparatus in a radio access network, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching, by the apparatus, to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a computer program comprising instructions which, when executed by an apparatus in a radio access network, cause the apparatus to perform at least the following: receiving, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a computer program comprising instructions for causing an apparatus in a radio access network to perform at least the following: receiving, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus in a radio access network to perform at least the following: receiving, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus in a radio access network to perform at least the following: receiving, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided an apparatus in a radio access network, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: receive, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switch to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided an apparatus in a radio access network, the apparatus comprising means for: receiving, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a method comprising: receiving, by an apparatus in a radio access network, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching, by the apparatus, to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a computer program comprising instructions which, when executed by an apparatus in a radio access network, cause the apparatus to perform at least the following: receiving, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a computer program comprising instructions for causing an apparatus in a radio access network to perform at least the following: receiving, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus in a radio access network to perform at least the following: receiving, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus in a radio access network to perform at least the following: receiving, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided an apparatus in a radio access network, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: transmit, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

According to another aspect, there is provided an apparatus in a radio access network, the apparatus comprising means for: transmitting, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

According to another aspect, there is provided a method comprising: transmitting, by an apparatus in a radio access network, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

According to another aspect, there is provided a computer program comprising instructions which, when executed by an apparatus in a radio access network, cause the apparatus to perform at least the following: transmitting, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

According to another aspect, there is provided a computer program comprising instructions for causing an apparatus in a radio access network to perform at least the following: transmitting, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

According to another aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus in a radio access network to perform at least the following: transmitting, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

According to another aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus in a radio access network to perform at least the following: transmitting, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

According to another aspect, there is provided a system comprising at least a first terminal device, a second terminal device, and an access node of a radio access network. The first terminal device is configured to: receive, from the second terminal device or the access node, a trigger signal indicating to switch to one or more states; and switch to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

According to another aspect, there is provided a system comprising at least a first terminal device, a second terminal device, and an access node of a radio access network. The first terminal device comprises means for: receiving, from the second terminal device or the access node, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

LIST OF DRAWINGS

In the following, various example embodiments will be described in greater detail with reference to the accompanying drawings, in which

FIG. 1 illustrates an example embodiment of a cellular communication network;

FIG. 2 illustrates an example embodiment of a horizontal new radio passive internet of things architecture;

FIG. 3 illustrates an example embodiment of a fixed vertical new radio passive internet of things architecture;

FIG. 4 illustrates an example embodiment of an opportunistic vertical new radio passive internet of things architecture;

FIG. 5 illustrates a signaling diagram according to an example embodiment;

FIG. 6 illustrates a signaling diagram according to an example embodiment;

FIG. 7 illustrates a flow chart according to an example embodiment;

FIG. 8 illustrates a flow chart according to an example embodiment;

FIG. 9 illustrates a flow chart according to an example embodiment;

FIG. 10 illustrates a flow chart according to an example embodiment;

FIG. 11 illustrates an example embodiment of an apparatus; and

FIG. 12 illustrates an example embodiment of an apparatus.

DETAILED DESCRIPTION

The following embodiments are exemplifying. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

In the following, different example embodiments will be described using, as an example of an access architecture to which the example embodiments may be applied, a radio access architecture based on long term evolution advanced (LTE Advanced, LTE-A), new radio (NR, 5G), beyond 5G, or sixth generation (6G) without restricting the example embodiments to such an architecture, however. It is obvious for a person skilled in the art that the example embodiments may also be applied to other kinds of communications networks having suitable means by adjusting parameters and procedures appropriately. Some examples of other options for suitable systems may be the universal mobile telecommunications system (UMTS) radio access network (UTRAN or E-UTRAN), long term evolution (LTE, substantially the same as E- UTRA), wireless local area network (WLAN or Wi-Fi), worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communications services (PCS), ZigBee®, wideband code division multiple access (WCDMA), systems using ultra- wideband (UWB) technology, sensor networks, mobile ad-hoc networks (MANETs) and Internet Protocol multimedia subsystems (IMS) or any combination thereof.

FIG. 1 depicts examples of simplified system architectures showing some elements and functional entities, all being logical units, whose implementation may differ from what is shown. The connections shown in FIG. 1 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system may also comprise other functions and structures than those shown in FIG. 1.

The example embodiments are not, however, restricted to the system given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties.

The example of FIG. 1 shows a part of an exemplifying radio access network.

FIG. 1 shows user devices 100 and 102 configured to be in a wireless connection on one or more communication channels in a radio cell with an access node 104, such as an evolved Node B (abbreviated as eNB or eNodeB) or a next generation Node B (abbreviated as gNB or gNodeB), providing the radio cell. The physical link from a user device to an access node may be called uplink (UL) or reverse link, and the physical link from the access node to the user device may be called downlink (DL) or forward link. A user device may also communicate directly with another user device via sidelink (SL) communication. It should be appreciated that access nodes or their functionalities may be implemented by using any node, host, server or access point etc. entity suitable for such a usage.

A communication system may comprise more than one access node, in which case the access nodes may also be configured to communicate with one another over links, wired or wireless, designed for the purpose. These links may be used for signaling purposes. The access node may be a computing device configured to control the radio resources of communication system it is coupled to. The access node may also be referred to as a base station, a base transceiver station (BTS), an access point or any other type of interfacing device including a relay station capable of operating in a wireless environment. The access node may include or be coupled to transceivers. From the transceivers of the access node, a connection may be provided to an antenna unit that establishes bi-directional radio links to user devices. The antenna unit may comprise a plurality of antennas or antenna elements. The access node may further be connected to a core network 110 (CN or next generation core NGC). Depending on the system, the counterpart on the CN side may be a serving gateway (S-GW, routing and forwarding user data packets), packet data network gateway (P-GW) for providing connectivity of user devices to external packet data networks, user plane function (UPF), mobility management entity (MME), access and mobility management function (AMF), or location management function (LMF), etc.

The user device illustrates one type of an apparatus to which resources on the air interface may be allocated and assigned, and thus any feature described herein with a user device may be implemented with a corresponding apparatus, such as a relay node.

An example of such a relay node may be a layer 3 relay (self-backhauling relay) towards the access node. The self-backhauling relay node may also be called an integrated access and backhaul (LAB) node. The 1AB node may comprise two logical parts: a mobile termination (MT) part, which takes care of the backhaul link(s) (i.e., link(s) between 1AB node and a donor node, also known as a parent node) and a distributed unit (DU) part, which takes care of the access link(s), i.e., child link(s) between the 1AB node and user device(s), and/or between the 1AB node and other 1AB nodes (multi-hop scenario).

Another example of such a relay node may be a layer 1 relay called a repeater. The repeater may amplify a signal received from an access node and forward it to a user device, and/or amplify a signal received from the user device and forward it to the access node.

The user device may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal, terminal device, active terminal device, passive terminal device, or user equipment (UE) just to mention but a few names or apparatuses. The user device may refer to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (mobile phone), smartphone, personal digital assistant (PDA), handset, device using a wireless modem (alarm or measurement device, etc.), laptop and/or touch screen computer, tablet, game console, notebook, multimedia device, reduced capability (RedCap) device, wireless sensor device, or any device integrated in a vehicle.

It should be appreciated that a user device may also be a nearly exclusive uplink only device, of which an example may be a camera or video camera loading images or video clips to a network. A user device may also be a device having capability to operate in Internet of Things (loT) network which is a scenario in which objects may be provided with the ability to transfer data over a network without requiring human- to-human or human-to-computer interaction. The user device may also utilize cloud. In some applications, a user device may comprise a small portable or wearable device with radio parts (such as a watch, earphones or eyeglasses) and the computation may be carried out in the cloud or in another user device. The user device (or in some example embodiments a layer 3 relay node) may be configured to perform one or more of user equipment functionalities. Various techniques described herein may also be applied to a cyberphysical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the implementation and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question may have inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals.

Additionally, although the apparatuses have been depicted as single entities, different units, processors and/or memory units (not all shown in FIG. 1) may be implemented.

5G enables using multiple input - multiple output (M1M0) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and employing a variety of radio technologies depending on service needs, use cases and/or spectrum available. 5G mobile communications may support a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applications (such as (massive) machinetype communications (mMTC), including vehicular safety, different sensors and realtime control. 5G may have multiple radio interfaces, namely below 6GHz, cmWave and mmWave, and also being integrable with existing legacy radio access technologies, such as the LTE. Integration with the LTE may be implemented, at least in the early phase, as a system, where macro coverage may be provided by the LTE, and 5G radio interface access may come from small cells by aggregation to the LTE. In other words, 5G may support both inter-RAT operability (such as LTE-5G) and inter-Rl operability (inter-radio interface operability, such as below 6GHz - cmWave - mmWave). One of the concepts considered to be used in 5G networks may be network slicing, in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the substantially same infrastructure to run services that have different requirements on latency, reliability, throughput and mobility. The current architecture in LTE networks may be fully distributed in the radio and fully centralized in the core network. The low latency applications and services in 5G may need to bring the content close to the radio which leads to local break out and multi-access edge computing (MEC). 5G may enable analytics and knowledge generation to occur at the source of the data. This approach may need leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. MEC may provide a distributed computing environment for application and service hosting. It may also have the ability to store and process content in close proximity to cellular subscribers for faster response time. Edge computing may cover a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing also classifiable as local cloud/fog computing and grid/mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and/or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications).

The communication system may also be able to communicate with other networks, such as a public switched telephone network or the Internet 112, or utilize services provided by them. The communication network may also be able to support the usage of cloud services, for example at least part of core network operations may be carried out as a cloud service (this is depicted in FIG. 1 by “cloud” 114). The communication system may also comprise a central control entity, or a like, providing facilities for networks of different operators to cooperate for example in spectrum sharing.

Edge cloud may be brought into radio access network (RAN) by utilizing network function virtualization (NFV) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head (RRH) or a radio unit (RU), or an access node comprising radio parts. It may also be possible that node operations are distributed among a plurality of servers, nodes or hosts. Carrying out the RAN real-time functions at the RAN side (in a distributed unit, DU 104) and non- real time functions in a centralized manner (in a central unit, CU 108) may be enabled for example by application of cloudRAN architecture.

It should also be understood that the distribution of labour between core network operations and access node operations may differ from that of the LTE or even be non-existent. Some other technology advancements that may be used include big data and all-lP, which may change the way networks are being constructed and managed. 5G (or new radio, NR) networks may be designed to support multiple hierarchies, where MEC servers may be placed between the core and the access node. It should be appreciated that MEC may be applied in 4G networks as well.

5G may also utilize non-terrestrial communication, for example satellite communication, to enhance or complement the coverage of 5G service, for example by providing backhauling. Possible use cases may be providing service continuity for machine-to-machine (M2M) or Internet of Things (loT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, and future railway/maritime/aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano) satellites are deployed). At least one satellite 106 in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on- ground cells may be created through an on-ground relay node 104 or by a gNB located on-ground or in a satellite.

6G networks are expected to adopt flexible decentralized and/or distributed computing systems and architecture and ubiquitous computing, with local spectrum licensing, spectrum sharing, infrastructure sharing, and intelligent automated management underpinned by mobile edge computing, artificial intelligence, short-packet communication and blockchain technologies. Key features of 6G may include intelligent connected management and control functions, programmability, integrated sensing and communication, reduction of energy footprint, trustworthy infrastructure, scalability and affordability. In addition to these, 6G is also targeting new use cases covering the integration of localization and sensing capabilities into system definition to unifying user experience across physical and digital worlds.

It is obvious for a person skilled in the art that the depicted system is only an example of a part of a radio access system and in practice, the system may comprise a plurality of access nodes, the user device may have access to a plurality of radio cells and the system may also comprise other apparatuses, such as physical layer relay nodes or other network elements, etc. At least one of the access nodes may be a Home eNodeB or a Home gNodeB.

Furthermore, the access node may also be split into: a radio unit (RU) comprising a radio transceiver (TRX), i.e., a transmitter (Tx) and a receiver (Rx); one or more distributed units (DUs) that may be used for the so-called Layer 1 (LI) processing and real-time Layer 2 (L2) processing; and a central unit (CU) (also known as a centralized unit) that may be used for non-real-time L2 and Layer 3 (L3) processing. The CU may be connected to the one or more DUs for example by using an Fl interface. Such a split may enable the centralization of CUs relative to the cell sites and DUs, whereas DUs may be more distributed and may even remain at cell sites. The CU and DU together may also be referred to as baseband or a baseband unit (BBU). The CU and DU may also be comprised in a radio access point (RAP).

The CU maybe defined as a logical node hosting higher layer protocols, such as radio resource control (RRC), service data adaptation protocol (SDAP) and/or packet data convergence protocol (PDCP), of the access node. The DU may be defined as a logical node hosting radio link control (RLC), medium access control (MAC) and/or physical (PHY) layers of the access node. The operation of the DU may be at least partly controlled by the CU. The CU may comprise a control plane (CU-CP), which may be defined as a logical node hosting the RRC and the control plane part of the PDCP protocol of the CU for the access node. The CU may further comprise a user plane (CU- UP), which may be defined as a logical node hosting the user plane part of the PDCP protocol and the SDAP protocol of the CU for the access node.

Cloud computing platforms may also be used to run the CU and/or DU. The CU may run in a cloud computing platform, which may be referred to as a virtualized CU (vCU). In addition to the vCU, there may also be a virtualized DU (vDU) running in a cloud computing platform. Furthermore, there may also be a combination, where the DU may use so-called bare metal solutions, for example application-specific integrated circuit (ASIC) or customer-specific standard product (CSSP) system-on-a-chip (SoC) solutions. It should also be understood that the distribution of labour between the above-mentioned access node units, or different core network operations and access node operations, may differ.

Additionally, in a geographical area of a radio communication system, a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which may be large cells having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The access node(s) of FIG. 1 may provide any kind of these cells. A cellular radio system may be implemented as a multilayer network including several kinds of radio cells. In multilayer networks, one access node may provide one kind of a radio cell or radio cells, and thus a plurality of access nodes may be needed to provide such a network structure.

For fulfilling the need for improving the deployment and performance of communication systems, the concept of “plug-and-play” access nodes may be introduced. A network which may be able to use “plug-and-play” access nodes, may include, in addition to Home eNodeBs or Home gNodeBs, a Home Node B gateway, or HNB-GW (not shown in FIG. 1). An HNB-GW, which may be installed within an operator’s network, may aggregate traffic from a large number of Home eNodeBs or Home gNodeBs back to a core network.

Regarding loT applications, the 3^rd generation partnership project (3GPP) has specified narrowband loT (NB-loT), enhanced machine type communication (eMTC), and NR reduced capability (RedCap) before NR Release 18 to satisfy the requirements on low-complexity and low-power devices for wide-area loT communication. For example, these loT devices may consume tens or hundreds of milliwatts of power during transceiving. However, to achieve the internet of everything, loT devices with even lower power consumption may be needed, for example for applications that need batteryless devices.

The number of loT connections has been growing rapidly in recent years and is predicted to be hundreds of billions by 2030. With more and more 'things’ expected to be interconnected for improving production efficiency and increasing the comforts of life, further reduction of size, complexity, and power consumption may be needed for loT devices. For example, replacing the battery of loT devices may be impractical due to the large consumption of materials and manpower.

However, energy may be harvested from the environment to power loT devices for self-sustainable communications, for example in applications with a very large number of devices (e.g., ID tags and sensors). For example, energy may be harvested by collecting solar power, piezoelectric energy, or radio wave energy. Radio wave energy conversion may be used to collect, for example, RFID, NFC, Bluetooth, 4G, 5G, WiFi and other radio wave energy in the surrounding environment and convert it into electrical energy. Currently, it may be possible to collect 5G radio frequency energy in a specific frequency band within a range of 180 meters in order to collect up to 6pW of electricity.

One issue with current 3GPP technologies for the target use cases is the capability of cooperation with energy harvesting considering the limited device size. Cellular devices may consume tens or even hundreds of milliwatts of power for the transceiving processing. Taking an NB-loT module as an example, the current absorption for receive processing may be approximately 60mA with a supply voltage higher than 3.1V, and 70mA for transmitting processing at OdBm transmit power. However, the output power provided by an energy harvester may be below 1 milliwatt, considering the small size of a few square centimeters for practical devices. Since the available power may be far less than the consumed power, it may be impractical to power cellular devices directly by energy harvesting in most cases.

One possible solution is to integrate energy harvesting with a rechargeable battery or supercapacitor. However, there are still a few issues to be solved. Firstly, both the rechargeable battery and supercapacitor may suffer from a shortened lifetime in practical cases. It is difficult to provide a constant charging current or voltage by energy harvesting, while long-time continuous charging may be needed due to the very small output power from the energy harvester. An inconstant charging current and long-time continuous charging are both harmful to battery life. For a supercapacitor, the lifetime may be significantly reduced in high-temperature environments (e.g., less than 3 years at 50 degrees centigrade).

Secondly, the device size may be significantly increased, if the device is equipped with a battery or supercapacitor. As a small-size button battery can provide a current of just a few tens of milliamperes, a battery with a much larger size (e.g., AA battery) may be needed to power cellular devices, but the size of the battery may be even larger than the NB-loT module itself. To store energy for a proper duration of working (e.g., one second), the required capacitance of a supercapacitor may be at the level of a hundred milli-farads. The size of such supercapacitors may also be larger than the NB-loT module itself.

Radio frequency identification (RFID) is a technology supporting batteryless tags (devices). The power consumption of commercial passive RFID tags may be as low as 1 microwatt. The key techniques enabling such low power consumption are envelope detection for downlink data reception, and backscatter communication for uplink data transmission. RFID is designed for short-range communications, whose typical effective range is less than 10 meters. As the air interface of RFID remains almost unchanged since 2005, this simple transmission scheme may become an obstacle for improving its link budget and capability of supporting a scalable network.

Backscatter communication is an energy-efficient communication technology for loT devices, for example. With backscatter communication, the loT devices may reflect or backscatter an external excitation signal (e.g., power beacon) by tuning a set of antenna impedances. Subsequently, the frequency, phase, and/or amplitude of the excitation signal may be modulated according to the data of these loT devices. Backscatter communication may enable the loT devices to transmittheir data without active transmission of radio frequency (RF) signals, which results in lower energy consumption. loT devices and/or other terminal devices can use backscattering to communicate with their peers and/or relay information to other devices.

There may be three types of backscatter communication systems: monostatic backscatter communication, bistatic backscatter communication, and ambient backscatter communication. In monostatic backscatter communication, the backscattering device (e.g., loT device) modulates and reflects a dedicated excitation signal that is transmitted by the intended receiver of the data.

In bistatic backscatter communication, the loT device modulates and reflects a dedicated high-power excitation signal from an RF source (e.g., a base station or a TV tower), which is different from the intended receiver.

In ambient backscatter communication, the dedicated high-power excitation signal is replaced by an RF data signal that is intended for other device(s). Hence, ambient backscatter communication does not require the generation of dedicated excitation signals.

Attracted by the low power consumption of backscatter communication, many non-3GPP technologies begin to put efforts into related research, such as WiFi, Bluetooth, ultra-wide band (UWB), and long range (LoRa). Various research shows that a few or tens of microwatts of power consumption can be achieved for passive tags based on or with small modifications to the above air interfaces. A significant proportion of the studies are targeting long-range communication. Among them, a LoRa tag implemented with commercial off-the-shelf components can send its sensing data to the receiver from 381 meters away, for example. Currently, most of the studies are focusing on independent detailed techniques for various optimization targets. It is difficult to see a comprehensive system design fully meeting the requirements of the target use cases.

To support and integrate passive loT in 5G NR network infrastructure, two challenges may need to be overcome first. The first challenge is how passive loT devices can obtain energy, since they themselves are not equipped with a power source. The second challenge is how to achieve long-distance backhaul, i.e., how can a batteryless passive loT device send a powerful enough signal that can reach the NR gNB, which may be located kilometers away from the passive loT device.

The latter challenge may be more difficult than the former one, and it may be the first time when such a problem occurs in practice. The reason for this is that previous passive loT deployments were based on Bluetooth or WiFi technologies, where the loT device just needs to cover short distances, in the order of meters.

However, an NR integration of passive loT may be challenging. This is because the energy obtained by the passive loT device through various techniques of energy harvesting may be very weak compared to what an NR UL signal power needs to be to compensate for the path loss of a radio link to the gNB, which may be a kilometer or more away from the passive loT device.

In summary, to enable a passive loT device to successfully communicate with the NR backhaul, there may be a need to provide a passive loT infrastructure for NR.

Some example embodiments are described below using principles and terminology of NR technology without limiting the example embodiments to NR communication systems, however.

Some example embodiments provide a framework comprising: a baseline set of NR passive loT architecture variants and their associated use-cases, NR states of terminal devices belonging to the above architecture variants, and state-change triggers that enable the integration of a passive loT device into the 5G NR network.

The NR passive loT (NR-ploT) architecture may support a horizontal or vertical deployment, depending on the use-case scenario. The horizontal NR-ploT (H- NR-ploT) hierarchy may be suitable for NR small-cell deployments. The vertical NR- ploT (V-NR-ploT) hierarchy may be suitable for NR macro-cell deployments.

FIG. 2 illustrates an example embodiment of the H-NR-ploT architecture, in which one or more passive loT devices 201, 202, 203 are in coverage of a short-range NR network 204 (e.g., NR small cells, indoor deployments, smart homes, etc.).

Herein a passive loT device may also be referred to as a passive loT terminal, a passive terminal device, a tag, a passive tag, or a passive radio. A passive terminal device (passive loT device) may be defined as a terminal device that is not equipped with a battery or any other power source. However, the passive terminal device may comprise a capacitor for storing harvested energy.

In the H-NR-ploT architecture, a given passive loT device 201 may be configured to: 1) communicate directly with the gNB 204, 2) offload its measurements to a neighboring passive loT device 202, 203 upon receiving an explicit trigger from the gNB 204 or from a neighboring passive loT device 202, 203, 3) relay measurements of one or more neighboring passive loT devices 202, 203 to the gNB 204, if the passive loT device 201 was instructed to do so by the gNB 204 via an explicit trigger, and/or harvest energy from radio signals transmitted by one or more neighboring passive loT devices 202, 203 and/or by the gNB 204.

The V-NR-ploT hierarchy may be used, when the passive loT devices are in coverage of a long-range NR network (e.g., macro-cell deployment). Three variants for the V-NR-ploT hierarchy are defined herein: 1) fixed V-NR-ploT for sparsely populated NR cells, 2) an opportunistic V-NR-ploT for densely populated NR cells, and 3) a hybrid V-NR-ploT for any other situation.

The V-NR-ploT variants may comprise passive loT device(s) and NR active device(s) that act as NR heads and enable the interactions between the passive loT terminals and the NR backhaul.

FIG. 3 illustrates an example embodiment of the fixed V-NR-ploT architecture, in which one or more passive loT devices 301, 302, 303 are in the immediate vicinity of an active NR terminal device 300. For example, the active NR terminal device 300 may be an NR relay, NR road-side unit, etc. The fixed V-NR-ploT architecture may be deployed in sparsely populated NR cells, and/or with a large passive loT device deployment, for example for automatized agriculture applications such as crop monitoring, fishery monitoring, etc.

The active terminal device 300 may act as a fixed or semi-fixed collectioncommunication unit, and it may enable the transfer of information (control signals and/or data) between the passive loT device(s) 301, 302, 303 and the gNB 304. In other words, the active terminal device 300 may be deployed in a known fixed position, or the active terminal device 300 may be moving between known positions to facilitate the radio link of the passive loT device(s) 301, 302, 303 to the NR backhaul 304. The active terminal device may refer to a terminal device that is equipped with a battery or connected to a power grid or other external power source, for example. The active terminal device 300 may also act as an enabler for energy harvesting by the passive loT device(s) 301, 302, 303 via the radio signals it relays to and from the gNB 304.

In the fixed V-NR-ploT architecture, a given passive loT device 301 may be configured to offload data (e.g., measurements) to one or more neghboring passive loT devices 302, 303, offload data (e.g., measurements) to the active terminal device 300, relay data (e.g., measurements) from a neighboring passive loT device 302, 303 to the active terminal device 300 and vice versa, and/or harvest energy by collecting radio signals to and from any neighboring passive loT device 302, 303 and/or the active terminal device 300.

FIG. 4 illustrates an example embodiment of the opportunistic V-NR-ploT architecture, in which one or more passive loT devices 401 are in the immediate vicinity of a random active NR terminal device 400, for example any moving NR UE that comes close to the passive loT terminal 401. In other words, the active NR terminal device 400 is being assigned the role of facilitating the radio link of the passive loT device(s) 401 to the NR backhaul 404. The gNB 404 may use an approximate location of the active terminal device 400, such as its serving beam information, to identify whether the active terminal device 400 is in the vicinity (e.g., within a pre-defined distance) of the one or more passive loT devices 401. Upon identifying that the active terminal device 400 is in the vicinity of the one or more passive loT devices 401, the gNB 404 may request the active terminal device 400 to relay radio signals (control signals and/or data) between any of the passive loT device(s) 401 and the gNB 404. The opportunistic V-NR-ploT architecture may be deployed in densely populated NR cells, for example smart homes, offices, smart factories, etc.

In the hybrid V-NR-ploT architecture, some active terminal devices may be purposely deployed at fixed locations, while other active terminal devices may be randomly assigned the relaying role by the gNB.

A passive loT device belonging to any of the H-NR-ploT or V-NR-ploT architectures described above may be triggered to switch to any of the following states: peer offloading, head offloading, energy harvesting, peer relay, peer control relay, and/or backhaul offloading.

In the peer-offloading state, the passive loT device transfers its measurements to another (neighboring) passive loT device. The passive loT device may embed the measurements into a raw transmit signal, i.e., a signal without a payload. The measurements may comprise sensor data such as temperature, humidity, etc. The peer-offloading state may be used, for example, if the passive loT device is running out of storage space in its internal memory, and/or it does not have any active terminal device in its vicinity. The peer-offloading state may be denoted as state A herein.

In the head-offloading state, the passive loT device transfers its measurements to an active terminal device. The head-offloading state may be denoted as state B herein.

In the energy-harvesting state, the passive loT device harvests and stores energy in a capacitor for a dedicated time period, by listening to any incoming radio signal(s). The energy-harvesting state may be denoted as state C herein.

In the peer-relay state, the passive loT device relays (by broadcast) measurements of another (neighboring) passive loT device. The peer-relay state may be denoted as state D herein.

In the peer-control-relay state, the passive loT device relays (by broadcast) an NR control signal targeting another (neighboring) passive loT device. The NR control signal may be a DL control signal or a relayed DL signal. For example, the control signal may be used to indicate the passive loT device to perform an operation such as collecting sensor data, or providing an identifier of the passive loT device to the network for locating/positioning the passive loT device. The peer-control-relay state may be denoted as state E herein.

In the backhaul-offloading state, the passive loT terminal transfers its measurements to the gNB. The backhaul-offloading state may be denoted as state F herein.

An active terminal device belonging to any of the V-NR-ploT architecture variants described above may be triggered to switch to any of the following states: collection, data relay, and/or control relay.

In the collection state, the active terminal device collects measurements from one or more passive loT devices. The collection may mean that the active terminal device stores the received measurements in its internal memory, and/or forwards them to the gNB. The collection state may be denoted as state G herein.

In the data-relay state, the active terminal device relays measurements of one or more passive loT devices to the gNB. The data-relay state may be denoted as state H herein. In the control-relay state, the active terminal device relays an NR control signal targeting a passive loT device. The NR control signal may be a DL control signal or a relayed DL signal. The control-relay state may be denoted as state 1 herein.

A terminal device (passive or active) may be statically configured or triggered to switch dynamically to one or more of the states described above via explicit trigger signals.

The trigger signal for an active terminal device may be in the form of an encoded payload sent over a dedicated control channel. For example, the active terminal device may be triggered by the gNB to switch to a certain state G/H/l or a combination of states via a short message indicator (SMI) sent over a physical downlink control channel (PDCCH), where three flags G, H, 1 may be configured, together with at least the time period P over which they are active, and the start S of the time period.

For example, if (G, H, 1) = (1, 0, 0) with P = 10 subframes, S = 0 subframes, then the active terminal device may collect data (e.g., measurements) according to state G from one or more passive loT devices for a duration of P=10 subframes, from the moment when the SMI was received.

Similarly, a passive loT device may be triggered by the gNB (via direct DL signaling or relayed DL signaling) to switch between the states A to F described above. Due to the limited processing capability of the passive loT device, the trigger signal may be realized by sending a known signal, for example a raw reference signal (RS), over state-specific radio resources. For example, an RS received over PRB_A may trigger the passive loT terminal to switch to state A (peer-offloading state). As another example, an RS received over PRB_E may trigger the passive loT terminal to switch to state E (peer-control-relay state). PRB is an abbreviation for physical resource block. It should be noted that the known signal transmitted over state-specific radio resources may also be used as a trigger signal for an active terminal device.

FIG. 5 illustrates a signaling diagram according to an example embodiment for the H-NR-ploT architecture. In this example embodiment, an access node (e.g., a gNB) of a radio access network may transmit, to a first passive terminal device in the radio access network, one or more trigger signals indicating the first terminal device to switch to one or more states. The one or more states indicate terminal requirements to support communication in the radio access network.

Referring to FIG. 5, in block 501, the access node transmits, to the first passive terminal device, a trigger signal indicating to switch to state C (i.e., the energyharvesting state described above). The first passive terminal device switches to state C as indicated by the trigger signal. State C indicates the first passive terminal device to harvest energy from one or more received radio signals.

In block 502, in response to switching to state C, the first passive terminal device harvests energy from the one or more received radio signals. The first passive terminal device may store the harvested energy in a capacitor. in block 503, the access node transmits, to the first passive terminal device, a trigger signal indicating to switch to state A (i.e., the peer-offloading state described above). The first passive terminal device switches to state A as indicated by the trigger signal. State A indicates the first passive terminal device to embed a first set of measurements into a raw transmit signal, i.e., a signal without a payload, to be transmitted to a neighboring terminal device.

In block 504, in response to switching to state A, the first passive terminal device transmits the raw transmit signal embedded with first set of measurements to the neighboring terminal device, for example to a second passive terminal device. In other words, the first passive terminal device offloads its measurements to the neighboring terminal device. The first passive terminal device may use the energy harvested in block 502 to transmit the first set of measurements.

Herein the terms “first passive terminal device” and “second passive terminal device” are used to distinguish the terminal devices, and they do not necessarily mean specific identifiers of the terminal devices.

In block 505, the access node transmits, to the first passive terminal device, a trigger signal indicating to switch to state D (i.e., the peer-relay state described above). The first passive terminal device switches to state D as indicated by the trigger signal. State D indicates the first passive terminal device to relay, by backscattering, a second set of measurements from the neighboring terminal device to the access node.

Herein the terms “first set of measurements” and “second set of measurements” are used to distinguish the measurement sets, and they do not necessarily mean a specific order of the measurement sets.

In block 506, the first passive terminal device receives the second set of measurements from the neighboring terminal device.

In block 507, in response to switching to state D, the first passive terminal device relays, by backscattering, the second set of measurements received from the neighboring terminal device to the access node.

In block 508, the access node transmits, to the first passive terminal device, a trigger signal indicating to switch to state E (i.e., the peer-control-relay state described above). The first passive terminal device switches to state E as indicated by the trigger signal. State E indicates the first passive terminal device to relay, by backscattering, one or more control signals received from the access node to the neighboring terminal device.

In block 509, the first passive terminal device receives a control signal from the access node.

In block 510, in response to switching to state E, the first passive terminal device relays, by backscattering, the control signal received from the access node to the neighboring terminal device. in block 511, the access node transmits, to the first passive terminal device, a trigger signal indicating to switch to state F (i.e., the backhaul-offloading state described above). The first passive terminal device switches to state E as indicated by the trigger signal. State F indicates the first passive terminal device to transmit, by backscattering, the first set of measurements (or a third set of measurements) to the access node (i.e., to offload the measurements of the first passive terminal device to the access node).

In block 512, in response to switching to state F, the first passive terminal device transmits, by backscattering, the first set of measurements (or the third set of measurements) to the access node. In other words, the first passive terminal device offloads its measurements to the access node.

FIG. 6 illustrates a signaling diagram according to an example embodiment for the V-NR-ploT architecture. In this example embodiment, an access node (e.g., a gNB) of a radio access network may transmit, to a first passive terminal device, via an active terminal device, one or more first trigger signals indicating the first terminal device to switch to one or more first states. Furthermore, the access node may transmit, to the active terminal device, one or more second trigger signals indicating the active terminal device to switch to one or more second states. The one or more first states and the one or more second states indicate terminal requirements to support communication in the radio access network.

Referring to FIG. 6, in block 601, the access node may identify that a second terminal device is within a pre-defined distance (e.g., in vicinity) to a first terminal device. The second terminal device may refer to the active terminal device, and the first terminal device may refer to the first passive terminal device.

In block 602, the access node transmits, to the first passive terminal device, via the active terminal device, a trigger signal indicating to switch to state A (i.e., the peer-offloading state described above). The first passive terminal device switches to state A as indicated by the trigger signal. State A indicates the first passive terminal device to embed a first set of measurements into a raw transmit signal, i.e., a signal without a payload, to be sent (transmitted) to a neighboring terminal device.

In block 603, in response to switching to state A, the first passive terminal device transmits the raw transmit signal embedded with the first set of measurements to the neighboring terminal device, for example to a second passive terminal device. In other words, the first passive terminal device offloads its measurements to the neighboring terminal device.

In block 604, the access node transmits, to the active terminal device, a trigger signal indicating to switch to state G (i.e., the collection state described above). The active terminal device switches to state G as indicated by the trigger signal. State G indicates the active terminal device to collect a set of measurements from one or more passive terminal devices, for example from the first passive terminal device and/or the second passive terminal device.

The trigger signals of blocks 602 and 604 may be transmitted in response to identifying that the active terminal device is within the pre-defined distance to the first passive terminal device. In block 605, the access node transmits, to the first passive terminal device, via the active terminal device, a trigger signal indicating to switch to state B (i.e., the head-offloading state described above). The first passive terminal device switches to state B as indicated by the trigger signal. State B indicates the first passive terminal device to transmit, by backscattering, the first set of measurements (or a third set of measurements) to the active terminal device.

In block 606, in response to switching to state B, the first passive terminal device transmits, by backscattering, the first set of measurements (or the third set of measurements) to the active terminal device. In other words, the first passive terminal device offloads its measurements to the active terminal device.

In block 607, in response to switching to state G, the active terminal device collects the first set of measurements (or the third set of measurements) received from the first passive terminal device. For example, the active terminal device may store the received measurements in its internal memory.

In block 608, the access node transmits, to the active terminal device, a trigger signal indicating to switch to state H (i.e., the data-relay state described above). The active terminal device switches to state H as indicated by the trigger signal. State H indicates the active terminal device to relay a set of measurements received from one or more passive terminal devices, for example from the first passive terminal device and/or the second passive terminal device, to the access node.

In block 609, the first passive terminal device transmits, by backscattering, the first set of measurements (or a fourth set of measurements) to the active terminal device.

In block 610, in response to switching to state H, the active terminal device relays the first set of measurements (or the fourth set of measurements) received from the first passive terminal device to the access node. The active terminal device may relay the first set of measurements with active transmission of one or more RF signals (instead of using backscattering).

In block 611, the access node transmits, to the first passive terminal device, via the active terminal device, a trigger signal indicating to switch to state D (i.e., the peer-relay state described above). The first passive terminal device switches to state D as indicated by the trigger signal. State D indicates the first passive terminal device to relay, by backscattering, a second set of measurements received from the neighboring terminal device to the active terminal device.

In block 612, the first passive terminal device receives the second set of measurements from the neighboring terminal device.

In block 613, in response to switching to state D, the first passive terminal device relays, by backscattering, the second set of measurements received from the neighboring terminal device to the active terminal device.

In block 614, in response to switching to state H, the active terminal device relays the second set of measurements received from the first passive terminal device to the access node. The active terminal device may relay the second set of measurements with active transmission of one or more RF signals (instead of using backscattering).

In block 615, the access node transmits, to the first passive terminal device, via the active terminal device, a trigger signal indicating to switch to state C (i.e., the energy-harvesting state described above). The first passive terminal device switches to state C as indicated by the trigger signal. State C indicates the first passive terminal device to harvest energy from one or more received radio signals.

In block 616, in response to switching to state C, the first passive terminal device harvests energy from the one or more received radio signals. The first passive terminal device may store the harvested energy in a capacitor.

In block 617, the access node transmits, to the active terminal device, a trigger signal indicating to switch to state 1 (i.e., the control-relay state described above). The active terminal device switches to state 1 as indicated by the trigger signal. State 1 indicates the active terminal device to relay one or more control signals received from the access node to one or more passive terminal devices, for example to the first passive terminal device and/or the second passive terminal device.

In block 618, the access node transmits, to the active terminal device, a first control signal targeted for the first passive terminal device.

In block 619, in response to switching to state 1, the active terminal device relays the first control signal received from the access node to the first passive terminal device. The active terminal device may relay the first control signal with active transmission of one or more RF signals (instead of using backscattering).

In block 620, the access node transmits, to the first passive terminal device, via the active terminal device, a trigger signal indicating to switch to state E (i.e., the peer-control-relay state described above). The first passive terminal device switches to state E as indicated by the trigger signal. State E indicates the first passive terminal device to relay, by backscattering, one or more control signals received from the access node to the neighboring terminal device.

In block 621, the access node transmits, to the active terminal device, a second control signal targeted for the second passive terminal device.

In block 622, in response to switching to state 1, the active terminal device relays the second control signal received from the access node to the first passive terminal device. Alternatively, or additionally, the active terminal device may relay the second control signal directly to the second passive terminal device. The active terminal device may relay the second control signal with active transmission of one or more RF signals (instead of using backscattering).

In block 623, in response to switching to state E, the first passive terminal device relays, by backscattering, the second control signal (targeted for the second passive terminal device) received from the active terminal device to the second passive terminal device.

FIG. 7 illustrates a flow chart according to an example embodiment of a method performed by an apparatus such as, or comprising, or comprised in, a passive terminal device in a radio access network. The passive terminal device may also be referred to as a first terminal device herein.

Referring to FIG. 7, in block 701, a trigger signal indicating to switch to one or more states is received from a terminal device (e.g., an active terminal device or a neighboring passive terminal device) or from an access node in the radio access network. For example, the trigger signal may comprise a reference signal received over one or more state-specific radio resources, wherein receiving the reference signal over the one or more state-specific radio resources indicate to switch to the one or more states. In block 702, the apparatus switches to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

For example, the terminal requirements may comprise performing at least one of: embedding, in a raw transmit signal, a first set of measurements to be sent to a neighboring terminal device, transmitting, by backscattering, the first set of measurements to the terminal device, transmitting, by backscattering, the first set of measurements to the access node, relaying, by backscattering, a second set of measurements from the neighboring terminal device to the terminal device or to the access node, relaying, by backscattering, a control signal from the terminal device or from the access node to the neighboring terminal device, and/or harvesting energy from one or more received radio signals.

The first set of measurements may comprise sensor data, such as temperature, humidity, etc., measured by the apparatus. The second set of measurements may comprise sensor data, such as temperature, humidity, etc., measured by the neighboring terminal device.

The control signal may be used to indicate the apparatus or the neighboring terminal device to perform an operation such as collecting the sensor data, or providing an identifier of the apparatus or the neighboring terminal device to the access node for locating/positioning the apparatus or the neighboring terminal device.

FIG. 8 illustrates a flow chart according to an example embodiment of a method performed by an apparatus such as, or comprising, or comprised in, an active terminal device in a radio access network. The active terminal device may also be referred to as a second terminal device herein.

Referring to FIG. 8, in block 801, a trigger signal indicating to switch to one or more states is received from an access node of the radio access network.

For example, the trigger signal may comprise a short message indicator comprising one or more state-specific bit flags, wherein a value of the one or more state-specific bit flags indicates to switch to the one or more states. The short message indicator may further indicate a time period over which to keep the one or more states active. The short message indicator may further indicate a start of the time period. In block 802, the apparatus switches to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

For example, the terminal requirements may comprise performing at least one of: collecting a set of measurements from one or more passive terminal devices, relaying the set of measurements from the one or more passive terminal devices to the access node, and/or relaying a control signal from the access node to the one or more passive terminal devices.

FIG. 9 illustrates a flow chart according to an example embodiment of a method performed by an apparatus such as, or comprising, or comprised in, an access node (e.g., gNB) in a radio access network.

Referring to FIG. 9, in block 901, the apparatus transmits, to a first terminal device (e.g., a passive terminal device) or to a second terminal device (e.g., an active terminal device) in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network. If the first trigger signal is transmitted to the second terminal device (active terminal device), then the second terminal device may relay or forward the first trigger signal to the first terminal device (passive terminal device).

For example, the first trigger signal may comprise a reference signal transmitted over one or more state-specific radio resources, wherein transmitting the reference signal over the one or more state-specific radio resources indicates to switch to the one or more first states.

For example, the first terminal requirements may indicate the first terminal device to perform at least one of: embedding, in a raw transmit signal, a first set of measurements to be sent to a neighboring terminal device, transmitting, by backscattering, the first set of measurements to the second terminal device, transmitting, by backscattering, the first set of measurements to the apparatus, relaying, by backscattering, a second set of measurements from the neighboring terminal device to the second terminal device or to the apparatus, relaying, by backscattering, a first control signal from the second terminal device or from the apparatus to the neighboring terminal device, and/or harvesting energy from one or more received radio signals.

FIG. 10 illustrates a flow chart according to another example embodiment of a method performed by an apparatus such as, or comprising, or comprised in, an access node (e.g., gNB) in a radio access network.

Referring to FIG. 10, in block 1001, the apparatus transmits, to a first terminal device (e.g., a passive terminal device) or to a second terminal device (e.g., an active terminal device) in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network. If the first trigger signal is transmitted to the second terminal device (active terminal device), then the second terminal device may relay or forward the first trigger signal to the first terminal device (passive terminal device).

In block 1002, the apparatus transmits, to the second terminal device, a second trigger signal indicating the second terminal device to switch to one or more second states, wherein the one or more second states indicate second terminal requirements for the second terminal device to support communication in the radio access network.

Herein the terms “first trigger signal” and “second trigger signal” are used to distinguish the trigger signals, and they do not necessarily mean a specific order of the trigger signals. Similarly, the terms “one or more first states” and “one or more second states” are used to distinguish the states corresponding to the first terminal device and the second terminal device, respectively. Similarly, the terms “first terminal requirements” and “second terminal requirements” are used to distinguish the terminal requirements corresponding to the first terminal device and the second terminal device, respectively.

For example, the second trigger signal may comprise a short message indicator comprising one or more state-specific bit flags, wherein a value of the one or more state-specific bit flags indicates to switch to the one or more second states. The short message indicator may further indicate a time period over which to keep the one or more second states active. The short message indicator may further indicate a start of the time period.

For example, the second terminal requirements may indicate the second terminal device to perform at least one of: collecting a set of measurements from the first terminal device, relaying the set of measurements from the first terminal device to the apparatus, and/or relaying a second control signal from the apparatus to the first terminal device.

Herein the terms “first control signal” and “second control signal” are used to distinguish the trigger signals, and they do not necessarily mean a specific order of the control signals.

The blocks, related functions, and information exchanges (messages) described above by means of FIGS. 5-10 are in no absolute chronological order, and some of them may be performed simultaneously or in an order differing from the described one. Other functions can also be executed between them or within them, and other information may be sent, and/or other rules applied. Some of the blocks or part of the blocks or one or more pieces of information can also be left out or replaced by a corresponding block or part of the block or one or more pieces of information.

FIG. 11 illustrates an example embodiment of an apparatus 1100, which may be an apparatus such as, or comprising, or comprised in, a terminal device in a radio access network. The terminal device may be, for example, a passive terminal device (passive loT device) or an active terminal device as described above.

The apparatus 1100 comprises at least one processor 1110. The at least one processor 1110 interprets computer program instructions and processes data. The at least one processor 1110 may comprise one or more programmable processors. The at least one processor 1110 may comprise programmable hardware with embedded firmware and may, alternatively or additionally, comprise one or more applicationspecific integrated circuits (ASICs).

The at least one processor 1110 is coupled to at least one memory 1120. The at least one processor is configured to read and write data to and from the at least one memory 1120. The at least one memory 1120 may comprise one or more memory units. The memory units may be volatile or non-volatile. It is to be noted that in some example embodiments there may be one or more units of non-volatile memory and one or more units of volatile memory or, alternatively, one or more units of non-volatile memory, or, alternatively, one or more units of volatile memory. Volatile memory may be for example random-access memory (RAM), dynamic random-access memory (DRAM) or synchronous dynamic random-access memory (SDRAM). Non-volatile memory may be for example read-only memory (ROM), programmable read-only memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash memory, optical storage or magnetic storage. In general, memories may be referred to as non-transitory computer readable media. The at least one memory 1120 stores computer readable instructions that are executed by the at least one processor 1110 to perform one or more of the example embodiments described above. For example, non-volatile memory stores the computer readable instructions, and the at least one processor 1110 executes the instructions using volatile memory for temporary storage of data and/or instructions.

The computer readable instructions may have been pre-stored to the at least one memory 1120 or, alternatively or additionally, they may be received, by the apparatus, via an electromagnetic carrier signal and/or may be copied from a physical entity such as a computer program product. Execution of the computer readable instructions causes the apparatus 1100 to perform one or more of the functionalities described above.

In the context of this document, a “memory” or “computer-readable media” or “computer-readable medium” may be any non-transitory media or medium or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

The apparatus 1100 may further comprise, or be connected to, an input unit 1130. The input unit 1130 may comprise one or more interfaces for receiving input. The one or more interfaces may comprise for example one or more temperature, motion and/or orientation sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons and/or one or more touch detection units. Further, the input unit 1130 may comprise an interface to which external devices may connect to.

The apparatus 1100 may also comprise an output unit 1140. The output unit may comprise or be connected to one or more displays capable of rendering visual content, such as a light emitting diode (LED) display, a liquid crystal display (LCD) and/or a liquid crystal on silicon (LCoS) display. The output unit 1140 may further comprise one or more audio outputs. The one or more audio outputs may be for example loudspeakers.

The apparatus 1100 further comprises a connectivity unit 1150. The connectivity unit 1150 enables wireless connectivity to one or more external devices. The connectivity unit 1150 comprises at least one transmitter and at least one receiver that may be integrated to the apparatus 1100 or that the apparatus 1100 may be connected to. The at least one transmitter comprises at least one transmission antenna, and the at least one receiver comprises at least one receiving antenna. The connectivity unit 1150 may comprise an integrated circuit or a set of integrated circuits that provide the wireless communication capability for the apparatus 1100. Alternatively, the wireless connectivity may be a hardwired application-specific integrated circuit (ASIC). The connectivity unit 1150 may comprise one or more components, such as: power amplifier, digital front end (DFE), analog-to-digital converter (ADC), digital-to- analog converter (DAC), frequency converter, (de) modulator, and/or encoder/decoder circuitries, controlled by the corresponding controlling units.

It is to be noted that the apparatus 1100 may further comprise various components not illustrated in FIG. 11. The various components may be hardware components and/or software components.

The apparatus 1200 of FIG. 12 illustrates an example embodiment of an apparatus such as, or comprising, or comprised in, an access node of a radio access network. The access node may also be referred to, for example, as a network node, a network element, a radio access network (RAN) node, a next generation radio access network (NG-RAN) node, a NodeB, an eNB, a gNB, a base transceiver station (BTS), a base station, an NR base station, a 5G base station, an access point (AP), an integrated access and backhaul (1AB) node, an IAB donor node, a distributed unit (DU), a central unit (CU), a baseband unit (BBU), a radio unit (RU), a radio head, a remote radio head (RRH), or a transmission and reception point (TRP).

The apparatus 1200 may comprise, for example, a circuitry or a chipset applicable for realizing one or more of the example embodiments described above. The apparatus 1200 may be an electronic device comprising one or more electronic circuitries. The apparatus 1200 may comprise a communication control circuitry 1210 such as at least one processor, and at least one memory 1220 storing instructions which, when executed by the at least one processor, cause the apparatus 1200 to carry out one or more of the example embodiments described above. Such instructions may, for example, include a computer program code (software) 1222 wherein the at least one memory and the computer program code (software) 1222 are configured, with the at least one processor, to cause the apparatus 1200 to carry out some of the example embodiments described above. Herein computer program code may in turn refer to instructions that cause the apparatus 1200 to perform one or more of the example embodiments described above. That is, the at least one processor and the at least one memory 1220 storing the instructions may cause said performance of the apparatus.

The processor is coupled to the memory 1220. The processor is configured to read and write data to and from the memory 1220. The memory 1220 may comprise one or more memory units. The memory units may be volatile or non-volatile. It is to be noted that in some example embodiments there may be one or more units of nonvolatile memory and one or more units of volatile memory or, alternatively, one or more units of non-volatile memory, or, alternatively, one or more units of volatile memory. Volatile memory may be for example random-access memory (RAM), dynamic random-access memory (DRAM) or synchronous dynamic random-access memory (SDRAM). Non-volatile memory may be for example read-only memory (ROM), programmable read-only memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash memory, optical storage or magnetic storage. In general, memories may be referred to as non-transitory computer readable media. The memory 1220 stores computer readable instructions that are executed by the processor. For example, non-volatile memory stores the computer readable instructions and the processor executes the instructions using volatile memory for temporary storage of data and/or instructions.

The computer readable instructions may have been pre-stored to the memory 1220 or, alternatively or additionally, they may be received, by the apparatus, via an electromagnetic carrier signal and/or may be copied from a physical entity such as a computer program product. Execution of the computer readable instructions causes the apparatus 1200 to perform one or more of the functionalities described above.

The memory 1220 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and/or removable memory. The memory may comprise a configuration database for storing configuration data. For example, the configuration database may store a current neighbour cell list, and, in some example embodiments, structures of the frames used in the detected neighbour cells.

The apparatus 1200 may further comprise a communication interface 1230 comprising hardware and/or software for realizing communication connectivity according to one or more communication protocols. The communication interface 1230 comprises at least one transmitter (Tx) and at least one receiver (Rx) that may be integrated to the apparatus 1200 or that the apparatus 1200 may be connected to. The communication interface 1230 may comprise one or more components, such as: power amplifier, digital front end (DFE), analog-to-digital converter (ADC), digital-to- analog converter (DAC), frequency converter, (de) modulator, and/or encoder/decoder circuitries, controlled by the corresponding controlling units.

The communication interface 1230 provides the apparatus with radio communication capabilities to communicate in the cellular communication system. The communication interface may, for example, provide a radio interface to one or more user devices. The apparatus 1200 may further comprise another interface towards a core network such as the network coordinator apparatus and/or to the access nodes of the cellular communication system.

The apparatus 1200 may further comprise a scheduler 1240 that is configured to allocate radio resources. The scheduler 1240 may be configured along with the communication control circuitry 1210 or it may be separately configured.

It is to be noted that the apparatus 1200 may further comprise various components not illustrated in FIG. 12. The various components may be hardware components and/or software components.

As used in this application, the term “circuitry” may refer to one or more or all of the following: a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry); and b) combinations of hardware circuits and software, such as (as applicable): i) a combination of analog and/or digital hardware circuit(s) with software/firmware and ii) any portions of hardware processor(s) with software (including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone, to perform various functions); and c) hardware circuit(s) and/or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (for example firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of example embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chipset (for example procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of the systems described herein may be rearranged and/or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

It will be obvious to a person skilled in the art that, as technology advances, the inventive concept may be implemented in various ways. The embodiments are not limited to the example embodiments described above, but may vary within the scope of the claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate, not to restrict, the example embodiments. LIST OF ABBREVIATIONS

3GPP: 3rd generation partnership project

4G: fourth generation

5G: new radio / fifth generation

6G: sixth generation

ADC: analog-to-digital converter

AP: access point

ASIC: application-specific integrated circuit

BBU: baseband unit

CN: core network

CPS: cyber-physical system

CSSP: customer-specific standard product

CU: central unit

CU-CP: central unit control plane

CU-UP: central unit user plane

DAC: digital-to-analog converter

DFE: digital front end

DL: downlink

DRAM: dynamic random-access memory

DSP: digital signal processor

DSPD: digital signal processing device

DU: distributed unit

EEPROM: electronically erasable programmable read-only memory eMTC: enhanced machine type communication eNB: evolved NodeB / 4G base station

FPGA: field programmable gate array

GEO: geostationary earth orbit gNB: next generation NodeB / 5G base station

GPU: graphics processing unit

HNB-GW: home node B gateway

H-NR-pIoT: horizontal new radio passive internet of things IAB: integrated access and backhaul

IMS: internet protocol multimedia subsystem loT: internet of things

LI: Layer 1

L2: Layer 2

L3: Layer 3

LCD: liquid crystal display

LCoS: liquid crystal on silicon

LED: light emitting diode

LEO: low earth orbit

LoRa: long range

LTE: longterm evolution

LTE-A: long term evolution advanced

M2M: machine-to-machine

MAC: medium access control

MANET: mobile ad-hod network

MEC: multi-access edge computing

M1M0: multiple input and multiple output

MME: mobility management entity mMTC: massive machine-type communications

MT: mobile termination

NB-loT: narrowband internet of things

NFV: network function virtualization

NGC: next generation core

NR: new radio

NR-ploT: new radio passive internet of things

PCS: personal communications services

PDA: personal digital assistant

PDCCH: physical downlink control channel

PDCP: packet data convergence protocol

P-GW: packet data network gateway PHY: physical

PLD: programmable logic device

PRE: physical resource block

PROM: programmable read-only memory

RAM: random-access memory

RAN: radio access network

RAP: radio access point

RAT: radio access technology

RedCap: reduced capability

RF: radio frequency

RFID: radio frequency identification

Rl: radio interface

RLC: radio link control

ROM: read-only memory

RRC: radio resource control

RRH: remote radio head

RU: radio unit

RX: receiver

SDAP: service data adaptation protocol

SDN: software defined networking

SDRAM: synchronous dynamic random-access memory

S-GW: serving gateway

SIM: subscriber identification module

SL: sidelink

SMI: short message indicator

SoC: system-on-a-chip

TRP: transmission and reception point

TRX: transceiver

TX: transmitter

UE: user equipment

UL: uplink UMTS: universal mobile telecommunications system UTRAN: UMTS radio access network

UWB: ultra-wideband vCU: virtualized central unit vDU: virtualized distributed unit

V-NR-ploT: vertical new radio passive internet of things

WCDMA: wideband code division multiple access

WiMAX: worldwide interoperability for microwave access

WLAN: wireless local area network

Claims

1. An apparatus in a radio access network, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: receive, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switch to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

2. The apparatus according to claim 1, wherein the terminal requirements comprise performing at least one of: embedding, in a raw transmit signal, a first set of measurements to be sent to a neighboring terminal device, transmitting, by backscattering, the first set of measurements to the terminal device, transmitting, by backscattering, the first set of measurements to the access node, relaying, by backscattering, a second set of measurements from the neighboring terminal device to the terminal device or to the access node, relaying, by backscattering, a control signal from the terminal device or from the access node to the neighboring terminal device, and/or harvesting energy from one or more received radio signals.

3. The apparatus according to claim 2, further being caused to: transmit, to the neighboring terminal device, the raw transmit signal embedded with the first set of measurements in response to switching to the one or more states, wherein the neighboring terminal device comprises a second passive terminal device.

4. The apparatus according to any of claims 2-3, further being caused to: relay, by backscattering, the second set of measurements received from the neighboring terminal device to the terminal device or to the access node in response to switching to the one or more states.

5. The apparatus according to any of claims 2-4, further being caused to: relay, by backscattering, the control signal received from the terminal device or from the access node to the neighboring terminal device in response to switching to the one or more states.

6. The apparatus according to any preceding claim, further being caused to: transmit, by backscattering, the first set of measurements to the terminal device in response to switching to the one or more states, wherein the terminal device comprises an active terminal device.

7. The apparatus according to any preceding claim, further being caused to: transmit, by backscattering, the first set of measurements to the access node in response to switching to the one or more states.

8. The apparatus according to any preceding claim, further being caused to: harvest energy from one or more received radio signals in response to switching to the one or more states.

9. The apparatus according to any preceding claim, wherein the trigger signal comprises a reference signal received over one or more state-specific radio resources, wherein receiving the reference signal over the one or more state-specific radio resources indicate to switch to the one or more states.

10. The apparatus according to any preceding claim, wherein the trigger signal is received from the access node via the terminal device.

11. The apparatus according to any preceding claim, wherein the apparatus comprises, or is comprised in, a first passive terminal device.

12. An apparatus in a radio access network, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: receive, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switch to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

13. The apparatus according to claim 12, wherein the terminal requirements comprise performing at least one of: collecting a set of measurements from one or more passive terminal devices, relaying the set of measurements from the one or more passive terminal devices to the access node, and/or relaying a control signal from the access node to the one or more passive terminal devices.

14. The apparatus according to claim 13, further being caused to: collect the set of measurements from the one or more passive terminal devices in response to switching to the one or more states.

15. The apparatus according to any of claims 13-14, further being caused to: relay the set of measurements received from the one or more passive terminal devices to the access node in response to switching to the one or more states.

16. The apparatus according to any of claims 13-15, further being caused to: relay the control signal received from the access node to the one or more passive terminal devices in response to switching to the one or more states.

17. The apparatus according to any of claims 12-16, wherein the trigger signal comprises a short message indicator comprising one or more state-specific bit flags, wherein a value of the one or more state-specific bit flags indicates to switch to the one or more states.

18. The apparatus according to claim 17, wherein the short message indicator further indicates a time period over which to keep the one or more states active.

19. The apparatus according to claim 18, wherein the short message indicator further indicates a start of the time period.

20. The apparatus according to any of claims 12-19, wherein the apparatus comprises, or is comprised in, an active terminal device.

21. An apparatus in a radio access network, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to: transmit, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

22. The apparatus according to claim 21, wherein the first terminal requirements indicate the first terminal device to perform at least one of: embedding, in a raw transmit signal, a first set of measurements to be sent to a neighboring terminal device, transmitting, by backscattering, the first set of measurements to the second terminal device, transmitting, by backscattering, the first set of measurements to the apparatus, relaying, by backscattering, a second set of measurements from the neighboring terminal device to the second terminal device or to the apparatus, relaying, by backscattering, a first control signal from the second terminal device or from the apparatus to the neighboring terminal device, and/or harvesting energy from one or more received radio signals.

23. The apparatus according to any of claims 21-22, wherein the first trigger signal comprises a reference signal transmitted over one or more state-specific radio resources, wherein transmitting the reference signal over the one or more statespecific radio resources indicate to switch to the one or more first states.

24. The apparatus according to any of claims 21-23, wherein the first trigger signal is transmitted to the first terminal device via the second terminal device.

25. The apparatus according to any of claims 21-24, further being caused to: transmit, to the second terminal device, a second trigger signal indicating the second terminal device to switch to one or more second states, wherein the one or more second states indicate second terminal requirements for the second terminal device to support communication in the radio access network.

26. The apparatus according to claim 25, wherein the second terminal requirements indicate the second terminal device to perform at least one of: collecting a set of measurements from the first terminal device, relaying the set of measurements from the first terminal device to the apparatus, and/or relaying a second control signal from the apparatus to the first terminal device.

27. The apparatus according to any of claims 25-26, wherein the second trigger signal comprises a short message indicator comprising one or more statespecific bit flags, wherein a value of the one or more state-specific bit flags indicates to switch to the one or more second states.

28. The apparatus according to claim 27, wherein the short message indicator further indicates a time period over which to keep the one or more second states active.

29. The apparatus according to claim 28, wherein the short message indicator further indicates a start of the time period.

30. The apparatus according to any of claims 25-29, wherein the second trigger signal is transmitted to the second terminal device in response to identifying that the second terminal device is within a pre-defined distance to the first terminal device.

31. The apparatus according to any of claims 21-30, wherein the first terminal device is a passive terminal device, and the second terminal device is an active terminal device.

32. The apparatus according to any of claims 21-31, wherein the apparatus comprises, or is comprised in, an access node of the radio access network.

33. An apparatus in a radio access network, the apparatus comprising means for: receiving, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

34. An apparatus in a radio access network, the apparatus comprising means for: receiving, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

35. An apparatus in a radio access network, the apparatus comprising means for: transmitting, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

36. A method comprising: receiving, by an apparatus in a radio access network, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching, by the apparatus, to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

37. A method comprising: receiving, by an apparatus in a radio access network, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching, by the apparatus, to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

38. A method comprising: transmitting, by an apparatus in a radio access network, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

39. A computer program comprising instructions for causing an apparatus in a radio access network to perform at least the following: receiving, from a terminal device or an access node in the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

40. A computer program comprising instructions for causing an apparatus in a radio access network to perform at least the following: receiving, from an access node of the radio access network, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

41. A computer program comprising instructions for causing an apparatus in a radio access network to perform at least the following: transmitting, to a first terminal device or to a second terminal device in the radio access network, a first trigger signal indicating the first terminal device to switch to one or more first states, wherein the one or more first states indicate first terminal requirements for the first terminal device to support communication in the radio access network.

42. A system comprising at least a first terminal device, a second terminal device, and an access node of a radio access network; wherein the first terminal device is configured to: receive, from the second terminal device or the access node, a trigger signal indicating to switch to one or more states; and switch to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.

43. A system comprising at least a first terminal device, a second terminal device, and an access node of a radio access network; wherein the first terminal device comprises means for: receiving, from the second terminal device or the access node, a trigger signal indicating to switch to one or more states; and switching to the one or more states, wherein the one or more states indicate terminal requirements to support communication in the radio access network.