WO2022101073A1

WO2022101073A1 - Reducing effects of power back-off

Info

Publication number: WO2022101073A1
Application number: PCT/EP2021/080522
Authority: WO
Inventors: Ali Karimidehkordi; Daniela Laselva; Sari Kaarina Nielsen; Ingo Viering; Tero Henttonen
Original assignee: Nokia Technologies Oy
Priority date: 2020-11-12
Filing date: 2021-11-03
Publication date: 2022-05-19

Abstract

Apparatuses and methods in a communication system for reducing effects of power back-off are presented. Using of the application or service in the terminal device is detected (400). A probability of a maximum power exposure event based on the application or service that is in use in the terminal device is determined (402). A maximum power exposure event mitigation action is performed (404) based on the determined probability of a maximum power exposure event.

Description

REDUCING EFFECTS OF POWER BACK-OFF

Field

The exemplary and non-limiting embodiments of the invention relate generally to wireless communication systems. Embodiments of the invention relate especially to apparatuses and methods in wireless communication networks.

Background

Wireless telecommunication systems are under constant development. There is a constant need for higher data rates, high quality of service and enhanced capacity. New frequency ranges are taken into use, especially in millimetre-wave (mm-wave) frequencies. Transmissions on these higher frequencies have properties that must be considered.

Transmit power of terminal devices of communication systems is controlled by various mechanisms. Transmit power control in the uplink direction performed by a serving access node is conventionally used for ensuring sufficiently strong received signal at network node and controlling uplink interference. Other mechanisms for controlling the transmit power include, for example, controlling exposure of a user of the terminal device to radio frequency radiation. Maximum permissible exposure (MPE) and specific absorption rate (SAR) guidelines have been established to define limits for radiation of radio energy towards the user. The terminal devices may have built-in functions to limit the transmit power in order to meet such limits. Other functions that may cause a power back-off situation in the terminal device can be equally foreseen.

Summary

The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to a more detailed description that is presented later.

According to an aspect of the present invention, there are provided apparatuses of claims 1 ,10, 17 and 18.

According to an aspect of the present invention, there are provided methods of claims 12 and 14.

According to an aspect of the present invention, there are provided computer programs comprising instructions of claim 15 and 16.

One or more examples of implementations are set forth in more detail in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. The embodiments and/or examples 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 of the invention.

List of drawings

Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which

Figures 1 and 2 illustrate examples of simplified system architecture of a communication system;

Figure 3 illustrates an example scenario;

Figures 4A, 4B and 5 are flowcharts illustrating some embodiments;

Figure 6 is a signalling chart illustrating an embodiment, Figure 7 is a flowchart illustrating an embodiment; and Figures 8, 9 and 10 illustrate simplified examples of apparatuses applying some embodiments of the invention.

Description of some embodiments

Fig. 1 shows devices 100 and 102. The devices 100 and 102 may, for example, be user devices or user terminals. The devices 100 and 102 are configured to be in a wireless connection on one or more communication channels with a node 104 or with each other. The node 104 is further connected to a core network 106. In one example, the node 104 may be an access node, such as (eZg)NodeB, serving devices in a cell. In one example, the node 104 may be a non-3GPP access node. The physical link from a device to a (e/g)NodeB is called uplink or reverse link and the physical link from the (eZg)NodeB to the device is called downlink or forward link. It should be appreciated that (eZg)NodeBs or their functionalities may be implemented by using any node, host, server or access point etc. entity suitable for such a usage.

A communications system typically comprises more than one (eZg)NodeB in which case the (eZg)NodeBs may also be configured to communicate with one another over links, wired or wireless, designed for the purpose. These links may be used for signalling purposes. The (eZg)NodeB is a computing device configured to control the radio resources of communication system it is coupled to. The NodeB may also be referred to as a base station, an access point or any other type of interfacing device including a relay station capable of operating in a wireless environment. The (eZg)NodeB includes or is coupled to transceivers. From the transceivers of the (eZg)NodeB, a connection is provided to an antenna unit that establishes bidirectional radio links to devices. The antenna unit may comprise a plurality of antennas or antenna elements. The (eZg)NodeB is further connected to the core network 106 (CN or next generation core NGC).

The device (also called a subscriber unit, user device, user equipment (UE), user terminal, terminal device, etc.) illustrates one type of an apparatus to which resources on the air interface are allocated and assigned, and thus any feature described herein with a device may be implemented with a corresponding apparatus, such as a relay node. An example of such a relay node is a layer 3 relay (self-backhauling relay) towards the base station.

The device typically refers to a device ( e.g. a portable or nonportable computing device) that includes wireless mobile communication devices operating with or without an universal subscriber identification module (USIM), 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 andZor touch screen computer, tablet, game console, notebook, and multimedia device. It should be appreciated that a device may also be a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. A device may also be a device having capability to operate in Internet of Things (loT) network which is a scenario in which objects are provided with the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction, e.g. to be used in smart power grids and connected vehicles. The device may also utilise cloud. In some applications, a device may comprise a user portable device with radio parts (such as a watch, earphones or eyeglasses) and the computation is carried out in the cloud. The device (or in some embodiments a layer 3 relay node) is configured to perform one or more of user equipment functionalities.

Various techniques described herein may also be applied to a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the implementation and exploitation of massive amounts of interconnected information and communications technology, 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 has 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 or NR (New Radio) enables using multiple input - multiple output (MIMO) antennas, many more base stations or nodes than the Long Term Evolution, 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 supports 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) machine-type communications (mMTC), including vehicular safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, e.g. below 6GHz or above 24 GHz, 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 is provided by the LTE and 5G radio interface access comes from small cells by aggregation to the LTE. In other words, 5G is planned to support both inter-RAT operability (such as LTE- 5G) and inter-RI operability (inter-radio interface operability, such as below 6GHz - cmWave, 6 or above 24 GHz - cmWave and mmWave). One of the concepts considered to be used in 5G networks is network slicing in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the same infrastructure to run services that have different requirements on latency, reliability, throughput and mobility.

The current architecture in LTE networks is fully distributed in the radio and fully centralized in the core network. The low latency applications and services in 5G require to bring the content close to the radio which leads to local break out and multi-access edge computing (MEC). 5G enables analytics and knowledge generation to occur at the source of the data. This approach requires leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content in close proximity to cellular subscribers for faster response time. Edge computing covers 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 is also able to communicate with other networks 112, such as a public switched telephone network, or a VoIP network, or the Internet, or a private network, 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.

The technology of Edge cloud may be brought into a radio access network (RAN) by utilizing network function virtualization (NFV) and software defined networking (SDN). Using the technology of 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 or base station comprising radio parts. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. Application of cloudRAN architecture enables RAN real time functions being carried out at or close to a remote antenna site (in a distributed unit, DU 108) and non-real time functions being carried out in a centralized manner (in a centralized unit, CU 110).

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

5G may also utilize satellite communication 116 to enhance or complement the coverage of 5G service, for example by providing backhauling. Possible use cases are 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 utilise geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular megaconstellations (systems in which hundreds of (nano)satellites are deployed). Each satellite 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 or by a gNB located on-ground or in a satellite.

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 (eZg)NodeBs, the device may have an access to a plurality of radio cells and the system may comprise also other apparatuses, such as physical layer relay nodes or other network elements, etc. At least one of the (eZg)NodeBs or may be a Home(eZg)nodeB. 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 are large cells, usually having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The (eZg)NodeBs 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 cells. Typically, in multilayer networks, one access node provides one kind of a cell or cells, and thus a plurality of (eZg)NodeBs are required 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” (eZg)NodeBs has been introduced. Typically, a network which is able to use “plug-and-play” (eZg)Node Bs, includes, in addition to Home (eZg)NodeBs (H(eZg)nodeBs), a home node B gateway, or HNB-GW (not shown in Fig. 1 ). A HNB Gateway (HNB-GW), which is typically installed within an operator’s network may aggregate traffic from a large number of HNBs back to a core network.

Fig.2 illustrates an example of a communication system based on 5G network components. A user terminal or user equipment 100 communicating via a 5G network 202 with a data network 112. The user terminal 100 is connected to a Radio Access Network RAN node, such as (eZg)NodeB 206 which provides the user terminal a connection to the network 112 via one or more User Plane Functions 208. The user terminal 100 is further connected to Core Access and Mobility Management Function, AMF 210, which is a control plane core connector for (radio) access network and can be seen from this perspective as the 5G version of Mobility Management Entity, MME, in LTE. The 5G network further comprises Session Management Function, SMF 212, which is responsible for subscriber sessions, such as session establishment, modify and release, and a Policy Control Function 214 which is configured to govern network behavior by providing policy rules to control plane functions.

In 5G or NR system, utilization of spectrum in higher frequency bands has been proposed in order to achieve higher data rates with lower latency, enhance network capacity, and provide sufficient services for a large number of subscribers. In 5G networks, the use of mm-wave such as frequency range 2 (FR2) that comprises bands between 24 GHz and 52 GHz has been proposed. The use of mm-wave bands presents some challenges, such as high propagation loss, atmospheric absorption, and health issues.

Fig. 3 illustrates an example of a terminal device scenario. As the communication transits to higher frequencies, the terminal devices may be equipped with a higher number of antenna panels to ensure effective radiation characteristics. Fig. 3 illustrates an embodiment where the terminal device 100 is equipped with four antenna panels 300, 302, 304, 306, each directed to a different radiation direction. Each antenna panel may provide a spherical radiation pattern, and a combined radiation pattern of the antenna panels may provide an omni-directional radiation pattern. Each antenna panel 300 - 306 may comprise a plurality of antenna elements, thus providing capability for adaptive spatial directivity, beamforming or multiple-input-multiple-output transmission and reception. In an embodiment, each antenna panel may form an antenna array, and examples of possible configurations of each antenna array include an array of 8x1 antennas (eight antennas in a row), 4x2 (four antennas in two rows), 8x2, etc. Because of the different directivity, each antenna panel may experience the environment in a different manner. For example, the antenna panels may be capable of detecting different sets of access nodes and with different reception qualities.

Transmissions in mm-wave under high power density may cause thermal damages to the body especially eye and skin. New governmental limits have been introduced on maximum power exposure (MPE) regulations to avoid such hazards and to limit the absorbed electromagnetic power density when a user body is exposed to mm-wave radiation. Therefore, as illustrated in Fig. 3, whenever a user body 308 reaches the vicinity of a transmitting panel the terminal device has to perform a power back-off (PBO) and reduce its transmitting power. These regulations are known as maximum permissible exposure (MPE) or Maximum Permissible Radio Frequency exposure regulations and they specify the effective isotropically radiated power (EIRP) to be in compliance with. The maximum allowed EIRP is averaged over time and depends on some factors such as power density (as a function of power and antenna gain), the distance between user body and antenna panel, and uplink (UL) duty cycle. As an example, a class three terminal device with a 2x2 antenna may require reducing its power up to 20 dB when the user touches the device.

When a user body approaches close to a transmitting panel of a terminal device operating on NR FR2 and the distance between the body and the panel falls below a safety distance, the following cases may happen:

Based on the MPE regulations, the terminal device will immediately perform a power back-off (PBO) (denoted as Power Management UE Maximum Power Reduction (P-MPR) in the 3GPP specifications). This may reduce the received signal power at the intended receiver (such as gNodeB), when the terminal device operates in power limitation. The presence of the user body may act as a blockage and degrade the uplink channel. In this case, the terminal device is likely to operate in power limitation and the PBO will harm the uplink reception. Furthermore, it has been shown that in some cases also downlink transmission may also be affected by the presence of user which covers the receiving panel.

As the received signal power reduces due to the sudden power back-off, the gNodeB may not be able to successfully decode the uplink packets transmitted by the terminal device. In some severe scenarios this may lead to a radio link failure as the maximum number of retransmissions is reached. The gNodeB may be unaware of the MPE event unless the terminal device indicates it with an MPE event signalling. There are various actions that may be taken to combat a power back-off may be, depending on the MPE condition, service requirement and available time budget. These actions may be panel switching, multi-transmission point coordination, multi-node connectivity, a handover to a neighbouring cell, reducing the uplink duty cycle reducing uplink data rates, move to a lower frequency band (e,g, FR1 ), or beam widening, for example. However, even upon an MPE indication by the terminal device, the gNodeB may not be able to timely react and cope with a severe power back-off.

Thus, it would be beneficial to be able to predict an MPE event before it happens such that both the gNodeB and terminal device would have time to take appropriate actions to mitigate problems caused by a power backoff.

Current MPE prediction algorithms are mainly based on the sensors of the terminal device to detect user proximity. Further operation of the terminal device is not determined. However, it is important to emphasize that not all services suffer from MPE issue equally at the same time and/or in the same extent. This is because some services and device combinations require the user to hold the terminal device in a certain way and they have different quality of service requirements in terms of throughput, reliability, latency, availability, for example. Certain types of holding the terminal device are more prone to cause MPE problems than others. Some applications or services by nature have a higher potential for the user to hold the terminal device close to the user’s body (such as hands or head) and therefore are more likely to trigger a power back-off due to the MPE event. For example, a voice call, a WhatsApp call, online gaming, watching YouTube, Facebook check and an Instagram video call are some examples of such MPE-prone applications due to the way users usually hold the terminal device during the use of the application or service.

The flowchart of Fig. 4A illustrates an embodiment. The flowchart illustrates an example of the operation of an apparatus. In an embodiment, the apparatus may be a terminal device or user equipment, a part of a terminal device or user equipment or any other apparatus capable of executing following steps.

In step 400, the apparatus is configured to detect using of an application or service in the terminal device.

In step 402, the apparatus is configured to determine a probability of a maximum power exposure event based on the application or service that is in use in the terminal device.

In step 404, the apparatus is configured to perform a maximum power exposure event mitigation action based on the determined probability of a maximum power exposure event.

In an embodiment, the mitigation action comprises at least one of decreasing an uplink transmission power, triggering a beam change procedure, transmitting to the network a warning of a possible maximum power exposure.

The flowchart of Fig. 4B illustrates an embodiment. The flowchart illustrates an example of the operation of an apparatus. In an embodiment, the apparatus may be a terminal device or user equipment, a part of a terminal device or user equipment or any other apparatus capable of executing following steps.

In step 410, the apparatus is configured to determine a correlation between an application or service and a way of holding of the terminal device when the application or service is in use in the terminal device. In an embodiment, terminal device’s proximity of user body is taken into account.

In step 412, the apparatus is configured to determine, based on the correlation, a probability of a maximum power exposure event when the application or service is in use in the terminal device. In step 414, the apparatus is configured to detect using of the application or service in the terminal device;

In step 416, the apparatus is configured to transmit to the network a warning of a possible maximum power exposure based on the determined probability of the application or service running in the terminal device.

In an embodiment, the terminal device may predict a potential service-based MPE event - before it happens - based on information one or more of the following: the running applications or services, the way of holding the device near the user’s body given the phone characteristics, user ergonomics, and the antenna panel(s) in use. In an embodiment, the terminal device form factor and design (the antenna panel locations in the device, for example) and how the user is likely to hold the given device is taken into account.

Further, when a service-based MPE event has been predicted, the terminal device may transmit a warning to the gNodeB serving the terminal device. This would indicate the potential risk of MPE to the gNB and provide the gNodeB a possibility to determine actions to mitigate effects of a power back-off performed by the terminal device during MPE. In an embodiment, the actions may be service-specific solutions (that are adequate and optimal for the affected services).

In an embodiment, the warning may comprise service-based information. For example, the information may comprise data on current service(s) in-use that can be indicated by Service Data Flow (SDF) and/or QoS Flow Identifier (QFI) and/or Data Radio Bearer Identifier (DRB ID), which have been associated to the running application(s). Further, the information may comprise the quality of service (QoS) characteristics required by the service(s) current in-use including uplink data rate, reliability and latency requirement. In an embodiment, the terminal device could be configured to omit these whenever these can be implicitly known at the network based on e.g. QFI. Vice-versa, the terminal device can be configured to report this information for example for a DU (in case CU and DU are separated in RAN split architecture), since the DU would have no service information, but is responsible of the means to react to an MPE event (for example by performing beam switching). Further, the information may comprise the expected service duration, or device operational preferences that reflect the device capability based on the current running application and service requirement. In an embodiment, the information may be further data about the device or subscriber identity.

In an embodiment, all of or some of the above may be contained in a transparent container to the core network. This would allow the transparent container to be passed to the CN layers that can better react to according to the service requirements and Mobile Edge Computing (MEC) handling could also be used to monitor the event and even control that the appropriate actions are done.

In an embodiment, the terminal device may be configured to estimate or obtain the correlation between service or application in use and a way of user holding the terminal device (user body proximity). The device characteristics (such as antenna design/location, size of the device) and user ergonomics may be taken into account. In an embodiment, basic correlation patterns for combinations of services or applications can be pre-loaded to the terminal device, for example by the device manufacturer or chipset maker. In an embodiment, correlation information may be gathered on-the-fly. The terminal device may learn the use patterns of the user of the device from the history of usage and ergonomic of the user. In an embodiment, pre-loaded information may be refined using information obtained during use.

As non-limiting examples of the knowledge to be acquired about the end-user interaction with the terminal device for a given application may be as follows:

• The end-user answers 80% of the phone calls during office-time using a headset. In this situation the probability of MPE is quite low.

• The end-user answers 80% of the phone calls outside office time (when the headset is not connected) by holding the device close to the head (the body covers almost all the panels).

• The user responds to 60 % of WhatsApp video calls by holding device with his/her right hand (two panels are covered in this case).

In an embodiment, a look-up table comprising correlation information may be uploaded and stored in a memory of the terminal device. The table may comprise default application/service-specific body proximity risk, i.e. the risk to hold the phone close to some body parts associated to an application in use). Table 1 is an exemplary look-up table showing both the pre-loaded or default values and the refined values of the “body proximity risk” for a non-limiting list of relevant applications. For applications for which the correlation to hold the phone close to some body parts is high enough, the device will predict that an MPE event is likely to happen and vice-versa.

Table 1

In an embodiment, the terminal device may be configured to calculate an MPE likelihood when a given application is in use (the application is open or data for this application is created). The calculation of the MPE likelihood may take into account the given application, the antenna panel(s) in use, and information on the way to hold the phone for this application.

In an embodiment, a default estimation of the MPE likelihood may be based on the application and the panel(s) in use, which can be pre-loaded to the device by the device manufacturer or chipset maker, implicitly accounting for the default way the device will be likely hold by the end-user.

In an embodiment, the terminal device may refine these application specific MPE estimates that are pre-loaded by learning from the history of usage of an application and the actual MPE statistics related to the given application. This may lead to increase or decrease the default MPE likelihood value for a given application based on the actual MPE events that were experienced while the application was in use in the past in the terminal device.

In an embodiment, the terminal device may store in a memory a look-up table maintaining information on the MPE likelihood associated to a given application. Table 2 is an exemplary look-up table showing both the default values and refined values of the MPE likelihood for a non-limiting list of applications.

Table 2

In an embodiment, the MPE estimates can depend on the panel in use as illustrated in Table 3 assuming the panels disposition in the device according to Fig. 3 as panel 1 300, panel 2 302, panel 3 304 and panel 4 306.

Table 3

As an example, consider a situation where a user has a phone call without using a headset. The terminal device is configured to determine that the user is going to hold the phone close to his/her head. Because of that, it can be expected that almost all the antenna panels will be close to the user body and, therefore, the terminal device may calculate that an MPE event is likely to occur. This will trigger an MPE warning signalling and corresponding actions.

In an embodiment, calculating an MPE likelihood may take into account also the current activity of applications. For example, any background activity of an application that generates background traffic and/or notifications (e.g. heart-beat/keep-alive traffic from a messaging application, email clients and other apps, push notifications from various applications) may be performed without user interaction, resulting in a low MPE likelihood. In an embodiment, the network or gNodeB may configure the operation of the terminal device regarding the MPE likelihood operations.

The flowchart of Fig. 5 illustrates an embodiment. The flowchart illustrates an example of the operation of an apparatus. In an embodiment, the apparatus may be a gNodeB, or a network node or a part of a gNodeB or a network node or any other apparatus capable of executing following steps.

In step 500, the apparatus is configured to transmit to a terminal device a command to start monitoring maximum power exposure events.

In step 502, the apparatus is configured to transmit to the terminal device a command to inform occurrence of a maximum power exposure event or a cancellation of a warning.

In step 504, the apparatus is configured to receive from the terminal device a warning of possible maximum power exposure event. In an embodiment, the warning comprises service or application specific information.

In step 506, the apparatus is configured to determine actions to be taken if event occurs.

In step 508, the apparatus is configured to transmit information on actions to the terminal device.

Thus, in an embodiment, the gNodeB may configure the terminal device to trigger a service based MPE warning, which indicates the MPE likelihood for a given service. The gNodeB may further configure the terminal device to send service and user subscriber related information during the warning phase. The terminal device transmits a service-based MPE warning to the network, whenever it predicts a potential MPE when a certain service is in- use. In addition, the terminal device sends service-related information to the network (such information can be transmitted together with the MPE warning message or as a separate signalling. The gNodeB may configure the terminal device to send a service based MPE warning cancellation (false alarm indication) if the predicted MPE is not going to happen (for example if the application or service ceases to be in use) or a confirmation if the MPE event happens.

Fig. 6 is a signalling chart illustrating an embodiment of MPE reporting between a terminal device 100 and a gNodeB 206.

The gNodeB 206 transmits a Radio Resource Control, RRC, Configuration message 600 to the terminal device100. The message may configure the terminal device to start monitoring service based MPE events. The message may further command the terminal device to inform occurrence of a maximum power exposure event or a cancellation of a warning.

The terminal device 100 determines 602 that these is a likelihood of an MPE event.

The terminal device 100 is configured to transmit a warning message 604 to the gNodeB 206. In an embodiment, the message comprises service specific information. In an embodiment, the information may also be sent in a separate message or messages. This information may comprise service requirements in terms of data rate, latency, and reliability or other limitations such as energy consumption or processing constraints. For example, for a WhatsApp video call the UE requirements are high data rate, low latency, and moderate reliability. In an embodiment, the terminal device may report a list of terminal device preferences to mitigate power back-off which are generated by considering running service and device capabilities. Examples of preferences are switching to frequency range FR1 , multi-node connectivity and conditional handover.

In an embodiment, when detecting a potential MPE event risk, the terminal device may, in addition to transmitting a warning message to gNodeB, also start preliminary actions to be prepared for the potential MPE event. For example, the terminal device may be configured to trigger sensors to sense environment more frequently and precisely. Also, it may be configured to perform channel estimation and Channel Quality Indicator, CQI, measurement from other panels, for example. In an embodiment, the terminal device may be configured to perform MPE related backoff needs for other panels than the current serving panel.

When the gNodeB receives the warning and information sent by the terminal device, the gNodeB may determine 606 actions to mitigate effects of the possible MPE event and power back-off. The gNodeB may reconfigure the terminal device based on the received warning and corresponding service information and inform 608 the terminal device about the available alternative solutions.

The reconfiguration actions may be service specific. For example, if the terminal device requires moderate uplink data rate and receive adequate signal quality from a neighbouring cell, it may request a conditional handover. With moderate load the terminal device may request for multi-node connectivity and in case of high uplink load the terminal device may request for spectrum switching to a lower frequency range (such as FR1 ). It may be noted that switching to FR1 may help as MPE regulation is not defined for FR1 frequencies but only for higher frequencies like FR2. SAR regulation, which is valid for FR1 , is different from the MPE regulation.

If the predicted MPE then happens, the terminal device is configured to transmit 610 MPE confirmation to the gNodeB and take necessary actions (that are planned in coordination with gNodeB during the warning phase) to mitigate power back-off limitations. If the MPE does not happen (the application or service causing the warning ceases to run, for example), the terminal device transmits an MPE cancelation signal 610 and prepares to operate in normal state.

In an embodiment, after receiving MPE confirmation from terminal device, the gNodeB may transmit 612 further configuration commands to the terminal device.

When the MPE event and power back-off situation is resolved, the terminal device may transmit indication 614 to the gNodeB, which may respond with an RRC configuration instructing the terminal device to return to normal operation.

In an embodiment, the terminal device may utilize the outcome of previous steps to update its service based MPE statistics and correlations and learn for proper operation in succeeding cases.

The proposed solution has many advantages over the prior art. Predicting an MPE event provides enough time budget for the terminal device and network to mitigate impacts of power back-off by taking appropriate actions mentioned above. Service and applications in use can help the MPE prediction to be more accurate and to be omitted when not needed, for example when no uplink transmissions are expected to take place. Further, transmitting service information helps the gNodeB to select the best decisions among the possible options to mitigate power back-off limitations.

The flowchart of Fig. 7 illustrates an embodiment. The flowchart illustrates an example of the operation of the terminal device in the situation of Fig. 6.

In step 700, the terminal device is configured to receive RRC configuration message from the gNodeB. The message may configure the terminal device to start monitoring service based MPE events. The message may further command the terminal device to inform occurrence of a maximum power exposure event or a cancellation of a warning.

In step 702, the terminal device is configured to determine correlation between an application or service and holding of the terminal device when the application or service is in use in the terminal device.

In step 704, the terminal device is configured to determine if an application or service having a possible high risk for MPE event has bee started.

If so, the apparatus is configured in step 706 to transmit a warning message to the gNodeB. As described above in connection with 604, the message may comprise service specific information.

If the MPE event happens 708, the terminal device is configured to transmit MPE confirmation to the gNodeB and take necessary actions (that are planned in coordination with gNodeB during the warning phase) to mitigate power back-off limitations, as described in connection with 610 above.

If the MPE does not happen (the application or service causing the warning ceases to run, for example), the terminal device transmits 712 an MPE cancelation signal and prepares to operate in normal state.

In an embodiment, the terminal device may update 714 its service based MPE statistics and correlations and learn for proper operation in succeeding cases.

Figs. 8, 9 and 10 illustrate embodiments. The figures illustrate a simplified example of an apparatus applying embodiments of the invention. It should be understood that the apparatus is depicted herein as an example illustrating some embodiments. It is apparent to a person skilled in the art that the apparatus may also comprise other functions and/or structures and not all described functions and structures are required. Although the apparatus has been depicted as one entity, different modules and memory may be implemented in one or more physical or logical entities.

Fig. 8 illustrates an example of an apparatus which may be a base station, (eZg)NodeB 206 or a part of base station or (e/g)NodeB.

The apparatus 206 of the example includes a control circuitry 900 configured to control at least part of the operation of the apparatus.

The apparatus may comprise one or more memories 902 for storing data. Furthermore, the one or more memories may store software 904 executable by the control circuitry 900. The one or more memories may be integrated in the control circuitry. The apparatus may comprise one or more interface circuitries 906, 908. The interface circuitries are operationally connected to the control circuitry 900. An interface circuitry 906 may be a set of transceivers configured to communicate wirelessly with terminal devices or user equipment of a wireless communication network. The interface circuitry may be connected to an antenna arrangement (not shown). The apparatus may also comprise a connection to a transmitter instead of a transceiver. The apparatus may further comprise an interface 908 configured to communicate with other network elements such a core network or other corresponding apparatuses, for example a user interface.

In an embodiment, the software 904 may comprise a computer program comprising program code means adapted to cause the control circuitry 900 of the apparatus to realise at least some of the embodiments described above.

Fig. 9 illustrates an example of an apparatus which may be user equipment or terminal device 100 or a part of user equipment or a terminal device.

The apparatus 100 of the example includes a control circuitry 1000 configured to control at least part of the operation of the apparatus.

The apparatus may comprise one or more memories 1002 for storing data. Furthermore, the one or more memories may store software 1004 executable by the control circuitry 1000. The one or more memories may be integrated in the control circuitry.

The apparatus may comprise one or more interface circuitries 1006, 1008. The interface circuitries are operationally connected to the control circuitry 1000. An interface circuitry 1006 may be a set of transceivers configured to communicate with a RAN node such as an (e/g)NodeB of a wireless communication network. The interface circuitry may be connected to an antenna arrangement 1010. In an embodiment, the antenna arrangement 1010 may comprise one or more antenna panels as illustrated in Fig. 3. The apparatus may also comprise a connection to a transmitter instead of a transceiver. The apparatus may further comprise a user interface 1008.

In an embodiment, the software 1004 may comprise a computer program comprising program code means adapted to cause the control circuitry 1000 of the apparatus to realise at least some of the embodiments described above. In an embodiment, as shown in Fig. 10, at least some of the functionalities of the apparatus of Fig. 8 may be shared between two physically separate devices, forming one operational entity. Therefore, the apparatus may be seen to depict the operational entity comprising one or more physically separate devices for executing at least some of the described processes. Thus, the apparatus of Fig. 10, utilizing such shared architecture, may comprise a remote control unit RCU 1100, such as a host computer or a server computer, operatively coupled (e.g. via a wireless or wired network) to a remote distributed unit RDU 1102 located in the (e/g)NodeB. In an embodiment, at least some of the described processes may be performed by the RCU 1100. In an embodiment, the execution of at least some of the described processes may be shared among the RDU 1102 and the RCU 1100.

In an embodiment, the RCU 1100 may generate a virtual network through which the RCU 1100 communicates with the RDU 1102. In general, virtual networking may involve a process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization may involve platform virtualization, often combined with resource virtualization. Network virtualization may be categorized as external virtual networking which combines many networks, or parts of networks, into the server computer or the host computer (e.g. to the RCU). External network virtualization is targeted to optimized network sharing. Another category is internal virtual networking which provides network-like functionality to the software containers on a single system. Virtual networking may also be used for testing the terminal device.

In an embodiment, the virtual network may provide flexible distribution of operations between the RDU and the RCU. In practice, any digital signal processing task may be performed in either the RDU or the RCU and the boundary where the responsibility is shifted between the RDU and the RCU may be selected according to implementation.

The steps and related functions described in the above and attached figures are in no absolute chronological order, and some of the steps may be performed simultaneously or in an order differing from the given one. Other functions can also be executed between the steps or within the steps. Some of the steps can also be left out or replaced with a corresponding step. The apparatuses or controllers able to perform the above-described steps may be implemented as an electronic digital computer, processing system or a circuitry which may comprise a working memory (random access memory, RAM), a central processing unit (CPU), and a system clock. The CPU may comprise a set of registers, an arithmetic logic unit, and a controller. The processing system, controller or the circuitry is controlled by a sequence of program instructions transferred to the CPU from the RAM. The controller may contain a number of microinstructions for basic operations. The implementation of microinstructions may vary depending on the CPU design. The program instructions may be coded by a programming language, which may be a high-level programming language, such as C, Java, etc., or a low- level programming language, such as a machine language, or an assembler. The electronic digital computer may also have an operating system, which may provide system services to a computer program written with the program instructions.

As used in this application, the term ‘circuitry’ refers to all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of circuits and software (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

This definition of ‘circuitry’ applies to all uses of this term in this application. As a further example, as used in this application, the term ‘circuitry’ would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and/or firmware. The term ‘circuitry’ would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device.

An embodiment provides a computer program embodied on a distribution medium, comprising program instructions which, when loaded into an electronic apparatus, are configured to control the apparatus to execute the embodiments described above.

The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, and a software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst several computers.

The apparatus may also be implemented as one or more integrated circuits, such as application-specific integrated circuits ASIC. Other hardware embodiments are also feasible, such as a circuit built of separate logic components. A hybrid of these different implementations is also feasible. When selecting the method of implementation, a person skilled in the art will consider the requirements set for the size and power consumption of the apparatus, the necessary processing capacity, production costs, and production volumes, for example.

In an embodiment, an apparatus in a communication system comprising means for detecting using of an application or service in the terminal device; determining a probability of a maximum power exposure event based on the application or service that is in use in the terminal device and performing a maximum power exposure event mitigation action based on the determined probability of a maximum power exposure event.

In an embodiment, an apparatus in a communication system comprising means for transmitting to a terminal device a command to start monitoring maximum power exposure events; transmitting to the terminal device a command to inform occurrence of a maximum power exposure event or a cancellation of a warning; receiving from the terminal device a warning of possible maximum power exposure event; determining actions to be taken if event occurs; and transmitting information on actions to the terminal device. The warning may comprise service or application specific information.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1 . An apparatus in a terminal device of a communication network, comprising: at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus to: detect using of an application or service in the terminal device; determine a probability of a maximum power exposure event based on the application or service that is in use in the terminal device; perform a maximum power exposure event mitigation action based on the determined probability of a maximum power exposure event.

2. The apparatus of claim 1 , wherein the determining comprises determining a correlation between the application or service and a way of holding of the terminal device when the application or service is in use in the terminal device; and utilising the determined correlation when determining the probability of a maximum power exposure event.

3. The apparatus of claim 1 or 2, wherein the mitigation action comprises at least one of decreasing an uplink transmission power, triggering a beam change procedure, transmitting to the network a warning of a possible maximum power exposure.

4. The apparatus of claim 3, wherein the warning of a possible maximum power exposure comprises service or application specific information which comprises one or more of the following: applications or services in use; quality of service characteristics required by the applications or services;

23 expected application or service duration; device operational preferences and device information; subscriber information.

5. The apparatus of claim 3, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to: detect a maximum power exposure event, and transmit to the network a message regarding the maximum power exposure.

6. The apparatus of claim 3, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to: transmit to the network a message cancellation of the warning when the application or service causing the warning is no longer in use.

7. The apparatus of any preceding claim, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to: receive from the network instructions of actions to be taken if a maximum power exposure event occurs.

8. The apparatus of any preceding claim, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to: where the terminal device has multiple antenna panels, determine which one or more of the panels is used for the application or service, and use the determined information of which one of more of the panels is used for the application or service in the determining of the probability of a maximum power exposure event.

9. The apparatus of any preceding claim, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to: determine a probability of a maximum power exposure event based on at least one of: stored information on the usage of the application or service; measurements made when the application or service is in use in the terminal device.

10. An apparatus in a communication system, comprising: at least processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the apparatus to: transmit to a terminal device a command to start monitoring maximum power exposure events; transmit to the terminal device a command to inform occurrence of a maximum power exposure event or a cancellation of a warning; receive from the terminal device a warning of possible maximum power exposure event, the warning comprising service or application specific information; determine actions to be taken if a maximum power exposure event occurs; transmit information on actions to the terminal device.

11 . The apparatus of claim 10, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus further to: receive from the terminal device a cancellation of the warning when the application or service causing the warning is no longer in use.

12. A method in a terminal device in a communication system comprising the steps of: detecting using of an application or service in the terminal device; determining a probability of a maximum power exposure event based on the application or service that is in use in the terminal device; performing a maximum power exposure event mitigation action based on the determined probability of a maximum power exposure event.

13. The method of claim 12, wherein: the determining comprises determining a correlation between an application or service and a way of holding of the terminal device when the application or service is in use in the terminal device; and utilising the determined correlation when determining the probability of a maximum power exposure event.

14. A method in a network element in a communication system comprising the steps of: transmitting to a terminal device a command to start monitoring maximum power exposure events; transmitting to the terminal device a command to inform occurrence of a maximum power exposure event or a cancellation of a warning; receiving from the terminal device a warning of possible maximum power exposure event, the warning comprising service or application specific information; determining actions to be taken if event occurs; transmitting information on actions to the terminal device.

15. A computer program comprising instructions for causing an apparatus at least to: detect using of the application or service in the terminal device; determining a probability of a maximum power exposure event based on the application or service that is in use in the terminal device; performing a maximum power exposure event mitigation action based on the determined probability of a maximum power exposure event.

16. A computer program comprising instructions for causing an apparatus at least to: transmit to a terminal device a command to start monitoring maximum power exposure events; transmit to the terminal device a command to inform occurrence of a maximum power exposure event or a cancellation of a warning; receive from the terminal device a warning of possible maximum power exposure event, the warning comprising service or application specific information;

26 determine actions to be taken if a maximum power exposure event occurs; transmit information on actions to the terminal device.

17. An apparatus in a communication system comprising means for detecting using of an application or service in the terminal device; means for determining a probability of a maximum power exposure event based on the application or service that is in use in the terminal device and means for performing a maximum power exposure event mitigation action based on the determined probability of a maximum power exposure event.

18. An apparatus in a communication system comprising means for transmitting to a terminal device a command to start monitoring maximum power exposure events; means for transmitting to the terminal device a command to inform occurrence of a maximum power exposure event or a cancellation of a warning; means for receiving from the terminal device a warning of possible maximum power exposure event, the warning comprising service or application specific information; means for determining actions to be taken if event occurs; and means for transmitting information on actions to the terminal device.

19 An apparatus in a terminal device in a communications system, the apparatus being configured to perform the method of claim 12 or claim 13.

20. An apparatus in a network element in a communications system, the apparatus being configured to perform the method of claim 14.

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