Positive measures for reducing the impact of power back-off

Abstract

This document discloses a solution for the case where a terminal device (100) detects a power back-off event. A method comprises: detecting, in the terminal device, a need for a reduction of uplink transmission power in an antenna panel of the terminal device (504); in response to the detection, performing at least one measurement (510) associated with: at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; and reporting (512) at least the measurement and / or the need for a reduction of uplink transmission power to an access node (104) of a serving cell.

Description

TECHNICAL FIELD

[0001] Various embodiments described herein relate to the field of wireless communications, and in particular to countering adverse effects of power back-off situations in wireless devices. BACKGROUND

[0002] Transmission power of a terminal device is controlled by various mechanisms. Uplink transmission power control procedures performed by a serving access node, e.g. a base station, are traditionally used to control uplink interference and power consumption of a terminal device. Other mechanisms for controlling transmission power include, for example, controlling user exposure of a terminal device to radio frequency radiation. Maximum Permissible Exposure (MPE) and Specific Absorption Rate (SAR) guidelines have been established to define limits on radio energy exposure of users. A terminal device can have built-in functionality to limit transmission power to meet these limits. Other functionalities that can cause power back-off situations in a terminal device can equally be foreseen. SUMMARY

[0003] Some aspects of the application are defined by the independent claims.

[0004] Some embodiments of the application are defined in the dependent claims.

[0005] Embodiments and features that are not within the scope of the independent claims, if any, described in this specification will be interpreted as examples useful for understanding the various embodiments of the application. Some aspects of the disclosure are defined by the independent claims.

[0006] According to one aspect, there is provided an apparatus for a terminal device, the apparatus comprising means for: detecting a need for uplink transmission power reduction in a serving antenna panel of the terminal device; in response to the detection, performing at least one measurement associated with: at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; and reporting at least the measurements and / or the need for uplink transmission power reduction to an access node of a serving cell.

[0007] In one embodiment, the means is configured to detect a need for uplink transmission power reduction in a serving antenna panel of the terminal device.

[0008] In one embodiment, the at least one measurement comprises a measurement of at least one of: a signal strength or a signal quality of a downlink signal received from the at least one non-serving cell.

[0009] In one embodiment, the at least one measurement comprises a measurement associated with uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel.

[0010] In one embodiment, the uplink power reduction comprises a power back-off caused by a maximum permissible exposure limit.

[0011] In one embodiment, the component is further configured to report, to an access node of the serving cell, a metric associated with an uplink transmission power of the at least one non-serving cell and / or the at least one non-serving antenna panel.

[0012] In one embodiment, the metric indicates a power back-off associated with a maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel.

[0013] In one embodiment, the component is configured to report the metric together with a measured downlink signal strength indicator or a measured downlink signal quality indicator of the at least one non-serving cell.

[0014] In one embodiment, the component is configured to perform at least one measurement and report the at least one measurement prior to the uplink transmission power reduction.

[0015] According to an aspect, there is provided an apparatus for a terminal device, the apparatus comprising a component for performing the following operations: performing measurements of at least one non-serving cell and / or at least one non-serving antenna panel of the terminal device; and reporting a measurement report to an access node of a serving cell of the terminal device, the measurement report comprising measurement data related to the at least one non-serving cell and / or the at least one non-serving antenna panel, the measurement report further comprising an indication of a need for an uplink transmission power reduction in the terminal device.

[0016] In one embodiment, the measurement data indicates a signal strength or a signal quality of a downlink signal received by the terminal device from the at least one non-serving cell.

[0017] In one embodiment, the indication comprises at least one information element indicating an uplink transmission power of the terminal device in the at least one non-serving cell and / or in the at least one non-serving antenna panel.

[0018] In one embodiment, the uplink power reduction comprises a power back-off caused by a maximum permissible exposure limit.

[0019] In one embodiment, the at least one information element indicates a power back-off associated with a maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel.

[0020] In one embodiment, the component is configured to prevent a handover to the non-serving cell or the non-serving antenna panel associated with the uplink transmission power reduction.

[0021] In one embodiment, the component is configured to switch the terminal device to a non-serving cell or a non-serving antenna panel independent of the uplink transmission power reduction.

[0022] In one embodiment, the component comprises at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform.

[0023] According to one aspect, there is provided a method comprising: detecting, by a terminal device, a need for uplink transmission power reduction in an antenna panel of the terminal device; in response to the detection, performing at least one measurement associated with at least one of: at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; and reporting, by the terminal device, at least the measurement and / or the need for uplink transmission power reduction to an access node of a serving cell.

[0024] In one embodiment, the terminal device detects a need for uplink transmission power reduction in a serving antenna panel of the terminal device.

[0025] In one embodiment, the at least one measurement comprises a measurement of at least one of: a signal strength or a signal quality of a downlink signal received from the at least one non-serving cell.

[0026] In one embodiment, the at least one measurement comprises a measurement associated with uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel.

[0027] In one embodiment, the uplink power reduction comprises a power back-off caused by a maximum permissible exposure limit.

[0028] In one embodiment, the terminal device reports, to the access node of the serving cell, a metric associated with uplink transmission power of the at least one non-serving cell and / or the at least one non-serving antenna panel.

[0029] In one embodiment, the metric indicates a power back-off associated with a maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel.

[0030] In one embodiment, the terminal device reports the metric together with a measured downlink signal strength indicator or a measured downlink signal quality indicator of the at least one non-serving cell.

[0031] In one embodiment, the terminal device performs the at least one measurement and reports the at least one measurement prior to the uplink transmission power reduction.

[0032] According to an aspect, there is provided a method comprising: receiving, by an access node, a measurement report from a terminal device connected to the access node, the measurement report comprising measurement data related to at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device, the measurement report further comprising an indication of a need for uplink transmission power reduction in the terminal device; and performing, by the access node, a handover decision for the terminal device based on the measurement data and the indication.

[0033] In one embodiment, the measurement data indicates a signal strength or a signal quality of a downlink signal received by the terminal device from the at least one non-serving cell.

[0034] In one embodiment, the indication comprises at least one information element indicating the uplink transmission power of the terminal device in the at least one non-serving cell and / or in the at least one non-serving antenna panel.

[0035] In one embodiment, the uplink power reduction comprises a power back-off caused by a maximum permissible exposure limit.

[0036] In one embodiment, the at least one information element indicates a power back-off associated with a maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel.

[0037] In one embodiment, the access node prevents a handover to the non-serving cell or the non-serving antenna panel associated with the uplink transmission power reduction.

[0038] In one embodiment, the access node hands over the terminal device to a non-serving cell or a non-serving antenna panel that is not associated with the uplink transmission power reduction.

[0039] According to an aspect, there is provided a computer program product embodied on a computer readable medium and comprising computer readable program code readable by a computer, wherein the computer readable program code configures the computer to perform a computer process comprising: detecting, in a terminal device, a need for uplink transmission power reduction in an antenna panel of the terminal device; in response to the detection, performing at least one measurement associated with: at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; and reporting, to an access node of a serving cell, at least the measurement and / or the need for uplink transmission power reduction.

[0040] According to an aspect, there is provided a computer program product embodied on a computer readable medium and comprising computer program code readable by a computer, wherein the computer program code configures the computer to perform a computer process comprising: receiving, in an access node, a measurement report from a terminal device connected to the access node, the measurement report comprising measurement data related to at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device, the measurement report further comprising an indication of a need for uplink transmission power reduction in the terminal device; and performing a handover decision for the terminal device based on the measurement data and the indication. BRIEF DESCRIPTION OF DRAWINGS

[0041] Embodiments are described below, by way of example only, with reference to the accompanying drawings in which

[0042] Figure 1 A wireless communication scenario to which some embodiments of the application can be applied is illustrated;

[0043] Figure 2 Embodiments of a terminal device comprising multiple antenna panels pointing in different spatial directions are illustrated, and the effect of uplink power backoff is also illustrated;

[0044] Figure 3 And Figure 4 Embodiments of a procedure for countering the effect of power backoff are illustrated;

[0045] Figure 5 A signalling diagram illustrating embodiments for reporting neighbour cell measurements when a power backoff event is detected in a serving antenna panel is illustrated;

[0046] Figure 6 The effect of embodiments of Figure 5 is illustrated;

[0047] Figure 7 A signalling diagram illustrating embodiments for reporting neighbour cell measurements when a power backoff event is detected in a non-serving antenna panel is illustrated;

[0048] Figure 8 The effect of embodiments of Figure 5 is illustrated; and

[0049] Figure 9 And Figure 10 A block diagram illustrating the structure of an apparatus according to some embodiments of the application is illustrated. DETAILED DESCRIPTION

[0050] The following embodiments are examples. Although the specification can

[0051] In the following, different exemplary embodiments will be described using a radio access architecture based on Long Term Evolution Advanced (LTE-A) or New Radio (NR, 5G) as an example of an access architecture to which the embodiments can be applied without limiting the embodiments to such an architecture. Those skilled in the art will recognize that the embodiments can be applied to other kinds of Universal Mobile Telecommunication System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, same as E-UTRA), Wireless Local Area Network (WLAN or WiFi), Worldwide Interoperability (WiMAX), Bluetooth®, Personal Communications Service (PCS), Wideband Code Division Multiple Access (WCDMA), systems using Ultra- Wide Band (UWB) technology, sensor networks, Mobile Ad-Hoc Networks (MANETs) and Internet Protocol Multimedia Subsystem (IMS) or any combination thereof.

[0052] Figure 1 An example of a simplified system architecture is depicted, only some elements and functional entities are shown, they are all logical units whose implementation can differ from what is shown. Figure 1 The connections to the other functional entities have been left out for the sake of simplicity. It is apparent to a person skilled in the art that the system typically includes more functional entities than the ones shown and that the connections can be different. Figure 1 The shown functions and structures are logical ones and the actual physical implementation of the system and the functions and structures can differ from what is shown.

[0053] However, the embodiments are not limited to the system given as an example but a person skilled in the art can apply the solution to other communication systems provided with the necessary features.

[0054] Figure 1 An example shows a part of an exemplary radio access network.

[0055] Figure 1Terminal devices or user equipments 100 and 102 configured to wirelessly connect with an access node, such as a (e / g)NodeB, 104 providing a cell on one or more communication channels in the cell are shown. The (e / g)NodeB refers to an eNodeB or a gNodeB as defined in the 3GPP specifications. The physical link from the user equipment to the (e / g)NodeB is called uplink or reverse link, and the physical link from the (e / g)NodeB to the user equipment is called downlink or forward link. It should be understood that the (e / g)NodeB or its functionalities can be implemented by using any node, host, server or access point etc. entity adapted for such usage.

[0056] The communication system typically includes more than one (e / g)NodeB, in which case the (e / g)NodeBs can also be configured to communicate with one another over links, either wired or wireless, designed for the purpose. These links can be used not only for signalling purposes, but also to route data from one (e / g)NodeB to another. The (e / g)NodeB is a computing device configured to control the radio resources of the communication system it is coupled to. The NodeB can also be called a base station, an access point, an access node, or any other type of interfacing device including a relay node capable of operating in a wireless environment. The (e / g)NodeB includes or is coupled to a transceiver. From the transceiver of the (e / g)NodeB, a connection is provided to an antenna unit, which establishes the bi-directional radio link to the user equipment. The antenna unit can include a plurality of antennas or antenna elements. The (e / g)NodeB is further connected to a core network 110 (CN or Next Generation Core NGC). Depending on the system, the counterpart on the CN side can be a serving gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW, for providing a connection for the user equipment (UE) to a packet data network) or a mobility management entity (MME) etc.

[0057] A user device (also called UE, user equipment, user terminal, terminal device, etc.) shows one type of device to which resources on the air interface are allocated and assigned, and thus any feature of the user device described herein can be implemented with a corresponding apparatus, such as a relay node. One example of such a relay node is a base station oriented layer 3 relay (self-backhauled relay).

[0058] A user device typically refers to a portable computing device including 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), a smartphone, a personal digital assistant (PDA), a handset, a device using a wireless modem (alarm device or measurement device etc.), a portable computer and / or a touch screen computer, a tablet, a game console, a notebook and a multimedia device. It should be appreciated that a user device can also be a nearly exclusive uplink device, an example of which is a camera or video camera that loads images or video clips to a network. A user device can also be a device that has the capability to operate in an Internet of Things (IoT) network, in which scenario objects are provided with the ability to transfer data over a network without human-to-human or human-to-computer interaction. A user device can also utilize the cloud. In some applications, a user device can comprise a small portable device (such as a watch, earphone or glasses) with a radio part, and the computing is performed in the cloud. A user device (or in some embodiments a layer 3 relay node) is configured to perform one or more of the user device functions. A user device can also be known as a subscriber unit, mobile station, remote terminal, access terminal, user terminal, or user equipment (UE), to mention only a few names or devices.

[0059] The various techniques described herein can also be applied to a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). A CPS can implement and exploit the synergy between networking and computing / processing

[0060] In addition, although the apparatus is depicted as a single entity, different units, processors and / or memory units (not all shown in Figure 1

[0061] ​​5G supports the use of multiple input multiple output (MIMO) antennas, many more base stations or nodes than LTE (so-called small cell concept) depending on service requirements, use cases and / or available frequency spectrum including cooperation of macro sites and utilization of multiple radio access technologies. 5G mobile communications systems are expected to have multiple radio interfaces, i.e. below 6GHz, cmWave and mmWave, and also be able to integrate with existing legacy radio access technologies such as LTE. Integration with LTE can be implemented at least in early phases of the system in which macro coverage is provided by LTE and 5G radio interface access comes from small cells by aggregation to 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), above 6GHz (cmWave, mmWave)). One of the concepts considered to be used in 5G networks is network slicing, in which multiple independent and dedicated virtual subnetworks (network instances) can be created in the same infrastructure to run services having different requirements on latency, reliability, throughput and mobility.

[0062] Current architecture in LTE networks is fully distributed in radio and typically fully centralized in the core network. Low latency applications and services in 5G require bringing 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 where data is generated, closer to the source itself. This approach requires leveraging resources that can not be continuously connected to the 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 the subscriber for faster response times. 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, self-organizing and self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and / or delay critical), critical communications (autonomous vehicles, traffic safety, real-time analysis, time-critical control, healthcare applications).

[0063] The communication system is also 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 system can also be used to provide cloud services, for example the core network operations can be carried out as a cloud service (this is depicted in Figure 1 as "cloud" 114). The communication system can further include central control entities for different operators' networks that provide facilities for cooperation, such as in spectrum sharing.

[0064] Edge cloud can be brought closer to the network nodes of Radio Access Network (RAN) by utilizing Network Function Virtualization (NFV) and Software-Defined Networking (SDN). Using edge cloud can mean that at least part of the task of the access node is carried out in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. The node operations can also be distributed among a plurality of servers, nodes or hosts. Application of cloudRAN architecture enables real-time functionality of the RAN to be carried out at the RAN side (in the Distributed Unit, DU 104) and non-real-time functionality to be carried out in a centralized manner (in the Centralized Unit, CU 108).

[0065] It should also be understood that the distribution of functions between core network operations and base station operations can differ from that of the LTE or even be non-existent. Some other technological advancements that can be used are Big Data and All-IP, which can change the way the network is built and managed. 5G (or New Radio, NR) networks are designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or NodeB (gNB). It should be understood that MEC can also be applied to 4G networks.

[0066] 5G can also utilize satellite communication to enhance or complement the 5G service coverage, for example by providing backhauling. Possible use cases are providing service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, as well as for future railway, maritime, and / or aeronautical communications systems. The satellite communication can utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems or even mega-constellations (systems that deploy hundreds of (nano) satellites). Each satellite 106 of the mega-constellation can be covering several satellite-enabled network entities creating small cells on the ground. The ground cells can be created by ground relay nodes 104 or gNBs, either located on the ground or in satellites.

[0067] It is clear to 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 can comprise a plurality of (e / g)NodeBs, the user equipment can access a plurality of radio cells, and the system can also comprise other apparatuses, such as physical layer relay nodes or other network elements. The at least one (e / g)NodeB can be a home (e / g)NodeB. In addition, in the geographical area of the radio communication system, a plurality of different kinds of radio cells can be provided as well as a plurality of radio cells. The radio cells can be macro cells (or umbrella cells), which are large-sized cells with a diameter typically up to tens of kilometers, or smaller cells such as micro, femto, or pico cells. Figure 1 The (e / g)NodeBs can provide any kind of these cells. The cellular radio system can be implemented as a multi-tier network comprising several kinds of cells. Typically, in a multi-tier network one access node provides one or more cells of one kind, and thus a plurality of (e / g)NodeBs is needed to provide such a network structure.

[0068] To meet the need for improving the deployment and performance of the communication system, the concept of a "plug and play" (e / g)NodeB has been introduced. Typically, in addition to the home (e / g)NodeB (H(e / g)NodeB), the network capable of using "plug and play" (e / g)NodeBs also comprises a home NodeB gateway or HNB-GW (not shown in the figure). Figure 1 The HNB gateway (HNB-GW), which is typically installed within the operator's network, can aggregate traffic from a large number of HNBs back to the core network.

[0069] As the communication is moving towards higher frequencies, the terminal equipment can be equipped with a larger number of antenna panels to ensure efficient radiation characteristics. Figure 2 An embodiment is shown in which the terminal equipment 100 is equipped with four antenna panels 200-206, each pointing in a different radiation direction. Each antenna panel can provide a spherical radiation pattern, and the combined radiation pattern of the antenna panels can provide an omnidirectional radiation pattern. Each antenna panel 200-206 can comprise a plurality of antenna elements, providing the capability of adaptive spatial directivity, beamforming, or multiple-input multiple-output transmission and reception. Each antenna panel can form an antenna array, and examples of possible configurations of each antenna array include 8x1 (one row of eight antennas), 4x2 (two rows of four antennas), 8x2, and so on. As an example, the terminal equipment 100 can be equipped with four antenna panels 200-206, each comprising eight antenna elements, providing a total of 32 antenna elements. Figure 2As illustrated, each antenna panel can experience the environment differently due to different directivity. For example, the antenna panels can be able to detect different sets of access nodes and have different reception qualities. For example, antenna panel 200 can be best suited for communicating with access node 104 located in the radiation direction of antenna panel 200, while antenna panels 204, 206 can be best suited for communicating with access nodes 122, 120 located in the respective radiation directions of antenna panels 204, 206, respectively.

[0070] For mobility and beam tracking purposes, a terminal device connected to a serving cell or serving access node (e.g., access node 104) can be configured by the serving cell to report signal strength measurements of neighboring cells. One example of a reported signal strength is reference signal received power (RSRP). Other examples are reference signal received quality (RSRQ) and signal to interference and noise ratio (SINR). The reporting can be event triggered or periodic. Some triggers are described in specifications of the Third Generation Partnership Project (3GPP). For reporting neighboring cell measurements, the terminal device can combine measurements from multiple antenna panels by selecting, for example, the strongest measurement among all antenna panel measurements for a particular neighboring cell. Thus, a cell level measurement for a certain neighboring cell can be generated by using the best measurement among all antenna panels. The neighboring cell measurements can be downlink measurements.

[0071] Maximum permissible exposure (MPE) is mentioned in the background. Governments have established exposure guidelines to prevent health problems due to thermal effects. MPE is a regulation on power density for mmWave systems. The Federal Communications Commission (FCC) has defined a threshold for MPE as 10 W / m2(1 mW / cm2). For a certain distance separating human tissue from an antenna, power backoff (PBO) is needed to comply with the regulation. However, the PBO needed is often quite large (e.g., up to 30 dB for a device transmitting with a maximum effective isotropic radiated power (EIRP) limit). Such a large PBO can cause unexpected radio link failure (RLF) because such a backoff reduces the uplink transmission capability for successfully delivering uplink data packets. The PBO can be triggered at different user antenna separations depending on the EIRP. For example, a 4x1 antenna array with an EIRP of 34 dBm can need PBO when the user is 14 cm away from the antenna. When the user is almost touching the antenna (2 mm separation), the maximum allowed EIRP can be only 10 dBm, so the power needs to be backed off by 24 dB. The transmission range of a terminal device is thus affected by PBO, and a 20-dB PBO can reduce the range by up to 90%. PBO applies only to the uplink, so it causes severe link imbalance when the UE is in power limited. This is especially true for mmWave systems, where the path loss is much higher than for sub-6 GHz systems. The PBO can also cause a significant reduction in the uplink data rate. Figure 2As shown, a hand near antenna panels 200 and 204 causes a Page Break (PBO) at the antenna panels, resulting in a link imbalance in communication between the antenna panels and the corresponding access nodes 104 and 122. Terminal device 100 can detect downlink signals from access nodes 104 and 122 via the corresponding antenna panels 200 and 204, but uplink transmission capacity is reduced due to the PBO, leading to the imbalance. Even though this does not prevent propagation—for example, uplink and downlink path losses are unaffected by the hand—the PBO throttles the transmission power of the terminal device, reducing the received power of the access nodes, thereby reducing the uplink SINR. Antenna panels 202 and 206 are not subject to the PBO; therefore, link balance between antenna panel 206 and access node 120 can be maintained.

[0072] Handover decisions are typically made based on downlink measurements. This, combined with the link imbalance mentioned above, can lead to a situation where a terminal device's connection is switched to an access node communicating with an antenna panel that is PBO-limited. Therefore, handover can result in uplink quality degradation and potential radio link failures. Conversely, a terminal device's connection via a PBO-limited antenna panel may fail due to uplink failures caused by PBO.

[0073] Figure 3 and Figure 4 A flowchart is shown for the process of managing connections in the PBO case. Figure 3 The process of the terminal device is shown, and Figure 4 The process of network nodes serving terminal devices (such as access nodes that perform handover decisions for terminal devices) is illustrated.

[0074] refer to Figure 3 The process includes the following operations performed by the terminal device: detecting (box 300) the need for reduced uplink transmission power in the antenna panel of the terminal device; in response to the above detection, performing (box 302) at least one measurement associated with at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; and reporting (box 304) at least one measurement to the access node of the serving cell.

[0075] In one embodiment, blocks 302 and 304 are executed before the uplink transmission power in the terminal device is reduced.

[0076] In one embodiment, block 302 also includes reporting the need for reduced uplink transmission power.

[0077] refer to Figure 4The procedure comprises the following operations performed by the network node: receiving (block 400) a measurement report from a terminal device connected to the access node, the measurement report comprising measurement data related to at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device, the measurement report further comprising an indication of a need for uplink transmission power reduction in the terminal device; and performing (blocks 402, 404) a handover decision for the terminal device based on the measurement data and the indication.

[0078] Block 402 can comprise determining whether or not a handover is to be performed. If no handover is to be performed, the procedure can end. Otherwise, the procedure can proceed to block 206, where the connection is handed over to one of the non-serving cells of the terminal device, thereby also causing the connection to be handed over from one antenna panel of the terminal device to another antenna panel of the terminal device.

[0079] Embodiments provide several advantages. The measurement report is triggered before the PBO (uplink transmission power reduction) is in effect, so that the effects of the PBO can be counteracted before the PBO is implemented. The terminal device sends information about the PBO to the network (access node) to enable a more informed handover decision. The network can then redirect the connection to a cell and antenna panel that is not affected by the PBO. The network can also avoid handing over the connection to an antenna panel that is affected by the PBO. Thus, radio link failures can be avoided or reduced.

[0080] In embodiments of block 300, the terminal device detects a need for uplink transmission power reduction in a serving antenna panel of the terminal device. The serving antenna panel can be understood as the antenna panel that transmits wireless signals for the connection between the terminal device and the serving cell.

[0081] In embodiments of blocks 302 and 304, the at least one measurement performed and reported to the serving access node comprises a measurement of at least one of a signal strength (e.g. RSRP or SINR) or a signal quality (e.g. RSRQ) of a downlink signal received from the at least one non-serving cell.

[0082] In one embodiment, the uplink power reduction comprises a PBO caused by an MPE limit. The need for PBO as a result of MPE can be detected by using any proximity detection sensor for detecting proximity of a user (e.g. a hand of the user) by the terminal device. The proximity detection can be based on (passive) infrared proximity sensors, short-range radar built into the antenna panel, etc.

[0083] Figure 5 A combination of Figure 3 and Figure 4signaling diagram of an embodiment of the application, and shows an embodiment in which a PBO event is detected in a serving antenna panel (i.e., an antenna panel used for communicating with a serving cell over a connection). Reference is made to Figure 5 The terminal device (UE) and the access node 104 establish a radio resource control (RRC) connection in block 500. The terminal device can configure the antenna panel 200 for transmitting and receiving radio signals over the RRC connection (see Figure 2 As a result, the access node 104 becomes a serving access node and the antenna panel 200 becomes a serving antenna panel, while the access nodes 1200 and 122 are non-serving access nodes and the antenna panels 202 to 206 are non-serving antenna panels.

[0084] In step 502, data and signaling information is transmitted over the RRC connection. Then, it is assumed that the user brings his / her hand close to the serving antenna panel 200. As a result, a proximity detection in the terminal device detects the proximity of the hand and triggers a PBO event for the serving antenna panel in the terminal device. In addition, depending on the position and proximity measurement of the hand, a PBO event can be triggered for one or more non-serving antenna panels. As a result of triggering the PBO event, the terminal device can trigger the execution of block 302 (block 506). In embodiments of block 302, the terminal device measures downlink signals received from non-serving access nodes via non-serving antenna panels (steps 508, 510) and obtains measurement data based on the measurements. For example, the terminal device can establish Table 1 in block 510 based on the measurements performed in block 302.

[0085] Table 1

[0086] Cell Identifier Metric (RSRP) Antenna Panel Identifier PBO 122 - 200 122 -80 dBm 204 10 dB 122 - 206 122 -90 dBm 202 No 120 - 200 120 - 204 120 -90 dBm 202 No 120 -85 dBm 206 No

[0087] The terminal device can perform all measurements indicated in Table 1, e.g., try to measure all non-serving cells using all non-serving antenna panels. As shown in Table 1, due to the different directivity of the antenna panels, only some antenna panels are able to detect signals from a certain non-serving access node. The PBO level can only be incorporated when the respective antenna panel is able to detect the non-serving access node. From the content of Table 1, the terminal device can construct a measurement report in step 512 and transmit the measurement report to the serving access node. The measurement report can comprise, for example, the information indicated in Table 2 or Table 3.

[0088] Table 2

[0089] Cell Identifier Metric (RSRP) PBO 122 -80 dBm 10 dB 120 -85 dBm 0 dB

[0090] Table 3

[0091] Cell Identifier Metric (RSRP) RSU LP 122 -80 dBm -95 dBm 120 -85 dBm -85 dBm

[0092] Thus, the measurement report can comprise a cell identifier of the detected non- serving cell, a metric measured from a downlink signal received from the respective non- serving cell, and a PBO metric associated with each non-serving cell. In the embodiment of Table 2, the PBO metric is a PBO on the nominal uplink transmission power of the antenna panel capable of communicating with the reported non-serving cell. In the embodiment of Table 3, the PBO metric is an absolute uplink transmission power reported, e.g., in dBm (decibel per milliwatt). The terminal device can filter the content of Table 1 in that in case multiple antenna panels are capable of detecting a certain non-serving cell, the measurement report only indicates the metric of the non-serving antenna panel providing the best measurement quality or signal strength. The granularity of the PBO metric can be determined according to implementation. For example, eight states (three bits) can be sufficient.

[0093] The measurement of the PBO metric can be understood as an embodiment of a measurement associated with the uplink transmission power in at least one non-serving cell and / or at least one non-serving antenna panel. The terminal device can measure the PBO metric based on the proximity detection and using a mapping table mapping the proximity to a PBO metric value. The mapping table can comprise information enabling to map each of a plurality of proximities or proximity ranges to a certain PBO metric, e.g., a PBO degree in dBm. The mapping table can be specific to each terminal device. For example, different mobile phone models can have different radiation characteristics and thus different mapping tables and values of the PBO metric for various proximities.

[0094] As the user can move his / her hand relative to the antenna panel, the PBO state can change during the warning period or when performing and reporting the measurement. Thus, the PBO metric can be understood as an estimate of the expected PBO level or target PBO.

[0095] As mentioned above, the terminal device can report to the serving access node a metric associated with the uplink transmission power of at least one non-serving cell and / or at least one non-serving antenna panel, e.g., a PBO metric associated with the MPE limitation caused by the detected user proximity. And as mentioned above, the terminal device can report this metric together with a measured downlink signal strength indicator (e.g., RSRP) or a measured downlink signal quality indicator (e.g., RSRQ) of at least one non-serving cell.

[0096] In one embodiment, the terminal device also measures a corresponding metric of the serving access node via the serving antenna panel and / or via a non-serving antenna panel. As a result, the measurement report can additionally indicate a PBO metric of the serving antenna panel and a measured metric of the antenna panel providing the best connection quality with the serving cell.

[0097] After receiving the measurement report in step 512, the serving access node can analyze the measurement report and determine the need for handover. By using the reported PBO metric, the access node is able to incorporate the PBO metric into the handover decision and adjust the reported (RSRP, RSRQ, SINR, etc.) metrics by the PBO metric. Thus, the access node is able to take into account the effect of PBO and make a handover decision that can reduce the probability of radio link failure. For example, if the measurement report indicates that the quality of connection via the serving access node falls below a threshold level when the PBO metric is incorporated, the access node can trigger a handover (block 514) to a non-serving cell that is independent of the uplink transmission power reduction, e.g., cell 120 in the case of the measurement report of Table 2 or Table 3. Thus, in block 516, the RRC connection is handed over from access node 104 to access node 120. In connection with the handover, the terminal device switches the RRC connection from the serving antenna panel 200 to the antenna panel determined in block 518 to provide the best connection quality with access node 120, i.e., antenna panel 206. Thus, access node 120 becomes the serving access node and antenna panel 206 becomes the serving antenna panel.

[0098] Steps 504 to 518 can be performed before the PBO actually takes effect in the antenna panel 200 (block 520). For example, detecting the PBO event 504 can trigger a one-time measurement report that is measured and reported before the PBO takes effect. Thus, the PBO can be prevented from impeding the connection quality. In another embodiment, block 504 can trigger a monitoring interval in which the terminal device operates in a mode in which it periodically measures and transmits measurement reports including the PBO metric. Unless operating in a particular mode, the terminal device can exclude reporting the PBO metric. As described above, the trigger of the monitoring interval is the detection of the proximity of the user's hand or the like to the terminal device at a first distance. The first distance can be greater than a second distance that triggers the PBO (block 520). Using such a warning zone between the first distance and the second distance enables the transmission of multiple measurement reports and monitoring of the terminal device's status for handover. The warning zone also provides time to counteract the effect of PBO and take appropriate measures. The periodicity and parameters included in the measurement reports during the warning zone can be configured by the serving access node. The length or duration of the warning zone depends on various characteristics, such as the mobility of the terminal device, the state of the radio channel, etc.

[0099] Figure 6 The effects of embodiments of the application are illustrated. Figure 5 Figure 6 ​In the middle, the uplink and downlink received signal levels of the antenna panel 200 and the serving access node 104 are shown by solid lines, the uplink and downlink received signal levels of the non-serving antenna panel 204 and the non-serving access node 122 are shown by dashed lines, and the uplink and downlink received signal levels of the non-serving antenna panel 206 and the non-serving access node 120 are shown by dash-dot lines. Upon detecting the proximity of the hand and as a result executing block 504, the terminal device can begin the measurements of block 506. For example, the measurements can be performed upon detecting the hand in proximity to the terminal device or upon detecting the hand within a particular detection area of the proximity sensor. As shown, the PBO in both antenna panels 200 and 204 will cause the uplink transmission power to drop the received power level at the serving access node (gNB) below the receiver sensitivity level, thereby severely degrading the uplink communication quality and causing a possible radio link failure. Without knowledge of the PBO at the antenna panel 204, the access node can trigger a handover to the access node 122 because of the reported RSRP being higher (see Table 1 above), thereby again causing the problem of PBO and radio link failure. However, by incorporating the PBO metric into the measurement report, the access node can scale the RSRP accordingly and detect that the access node 120, which is not associated with PBO, will provide the best connection quality. As a result, a handover to the access node that provides satisfactory uplink performance can be made.

[0100] In one embodiment, the access node uses the measurement report to prevent a handover to a non-serving cell or non-serving antenna panel associated with a reduction in uplink transmission power. Figure 7 Embodiments are shown. In Figure 7 In the middle, the uplink and downlink received signal levels of the antenna panel 200 and the serving access node 104 are shown by solid lines, the uplink and downlink received signal levels of the non-serving antenna panel 204 and the non-serving access node 122 are shown by dashed lines, and the uplink and downlink received signal levels of the non-serving antenna panel 206 and the non-serving access node 120 are shown by dash-dot lines. Upon detecting the proximity of the hand and as a result executing block 504, the terminal device can begin the measurements of block 506. For example, the measurements can be performed upon detecting the hand in proximity to the terminal device or upon detecting the hand within a particular detection area of the proximity sensor. As shown, the PBO in both antenna panels 200 and 204 will cause the uplink transmission power to drop the received power level at the serving access node (gNB) below the receiver sensitivity level, thereby severely degrading the uplink communication quality and causing a possible radio link failure. Without knowledge of the PBO at the antenna panel 204, the access node can trigger a handover to the access node 122 because of the reported RSRP being higher (see Table 1 above), thereby again causing the problem of PBO and radio link failure. However, by incorporating the PBO metric into the measurement report, the access node can scale the RSRP accordingly and detect that the access node 120, which is not associated with PBO, will provide the best connection quality. As a result, a handover to the access node that provides satisfactory uplink performance can be made. Figure 5 In the middle, the uplink and downlink received signal levels of the antenna panel 200 and the serving access node 104 are shown by solid lines, the uplink and downlink received signal levels of the non-serving antenna panel 204 and the non-serving access node 122 are shown by dashed lines, and the uplink and downlink received signal levels of the non-serving antenna panel 206 and the non-serving access node 120 are shown by dash-dot lines. Upon detecting the proximity of the hand and as a result executing block 504, the terminal device can begin the measurements of block 506. For example, the measurements can be performed upon detecting the hand in proximity to the terminal device or upon detecting the hand within a particular detection area of the proximity sensor. As shown, the PBO in both antenna panels 200 and 204 will cause the uplink transmission power to drop the received power level at the serving access node (gNB) below the receiver sensitivity level, thereby severely degrading the uplink communication quality and causing a possible radio link failure. Without knowledge of the PBO at the antenna panel 204, the access node can trigger a handover to the access node 122 because of the reported RSRP being higher (see Table 1 above), thereby again causing the problem of PBO and radio link failure. However, by incorporating the PBO metric into the measurement report, the access node can scale the RSRP accordingly and detect that the access node 120, which is not associated with PBO, will provide the best connection quality. As a result, a handover to the access node that provides satisfactory uplink performance can be made. Figure 7 Figure 5

[0101] ​​The access node can use the received measurement reports and PBO metrics when making the next handover decision. For example, if the serving antenna panel has not experienced a PBO, the access node can trigger a handover in a conventional manner, such as when a downlink connection quality to the terminal device is detected to have degraded below a threshold. In this case, access node 104 can use the PBO metrics received in step 512 to select a target cell for handover that is not associated with a PBO (box 704). Accordingly, the access node can avoid the situation where the operational link is replaced by a link that has suffered a PBO. The handover can be performed in box 516 and the serving antenna panel can be selected in box 518 in the manner described above.

[0102] Figure 8 It shows Figure 7 The effect of the embodiment is as follows. Assume the terminal device is moving, causing the signal quality towards the serving access node 104 to degrade, while the signal quality towards other access nodes 120, 122 is increasing. When a PBO event is detected in the non-serving antenna panel 204, the terminal device can trigger the reporting of the PBO metric in the measurement report. When the signal quality of the serving access node drops below a handover threshold level, the serving access node can execute block 704 and make a handover decision. Without reporting the PBO metric, the access node might select access node 122 as the handover target because the reported downlink signal quality is higher. However, this would be a poor decision due to the PBO in the corresponding antenna panel 204, potentially leading to radio link failure due to poor uplink quality. By incorporating the PBO metric into the measurement report, the access node can consider the PBO metric in block 704 and select access node 120 as the handover target, thereby reducing the probability of radio link failure after handover.

[0103] Figure 9 An embodiment showing the structure of a device for performing the functions of a network node in the above embodiments is provided, for example, Figure 4 The process or any embodiment thereof. As described above, the means for a network node can be configured to perform handover decisions for a terminal device (e.g., terminal device 100 described above). In one embodiment, the means may be a circuit system or electronic device that implements some embodiments of the present invention in the network node. The means for performing the above functions can therefore be included in such a device, for example, the means may include circuit systems such as chips, chipsets, processors, microcontrollers, etc., or combinations of such circuit systems for a network node.

[0104] refer to Figure 9The apparatus can comprise a communications controller 10 that provides the apparatus with the ability to perform the above-described functions of a network node. In some embodiments, the apparatus can comprise a radio interface 25 that provides the apparatus with radio communications capability, and the communications controller 10 can employ the radio interface 25. The radio interface 25 can enable wireless communications with terminal devices served by the network node. The radio interface 25 can comprise a plurality of antennas and associated analogue components required for transmission and reception of radio signals, such as amplifiers, filters, frequency converters and analogue-to-digital converters. The communications controller 10 and / or the radio interface 25 can comprise a radio modem configured to perform transmission and reception of messages in a cellular network. In some embodiments, the radio interface is used for communication with other network nodes.

[0105] In some embodiments, the apparatus comprises a second communications interface 22 configured to provide the apparatus with communications capability towards the core network 110. In some embodiments, the communications interface 22 can also be used for communication with other network nodes via wired connections. In the context of a 5G network, the communications interface 22 can be configured to communicate over an Xn interface, an Fl interface and / or an NG interface.

[0106] The communications controller 10 can comprise at least one processor or processing circuitry. The apparatus can further comprise a memory 20 storing one or more computer program products 24 that configure the operation of the above-described processor of the apparatus. The memory 20 can 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 removable memory. The memory 20 can also store a configuration database 26 that stores operational configurations of the apparatus. For example, the configuration database 26 can store rules for incorporating uplink performance of terminal devices into handover decisions in the above-described manner.

[0107] The communication controller can comprise an RRC controller 12 configured to establish, operate and terminate RRC connections between the network node and terminal devices connected to the network node. The communication controller 10 can further comprise a handover controller 14 configured to make handover decisions (blocks 514 and 704). The handover controller can comprise as sub-circuitry a downlink estimation circuitry 19 and an uplink estimation circuitry 17. The downlink estimation circuitry 19 can be configured to process downlink measurement data received from a terminal device for which a handover decision is made. The downlink measurement data can comprise RSRP, RSRQ, SINR or other metrics measured by the terminal device from downlink signals received from neighbouring cells. The uplink estimation circuitry 17 can be configured to process uplink transmission power metrics received from the terminal device, e.g. PBO metrics associated with each neighbouring cell. The handover controller can then select a target cell for handover based on the output of both circuitries 17, 19, e.g. the combined performance of the uplink and downlink of each neighbouring cell as a candidate target cell for handover. The handover controller can thus select a target cell for handover that is able to provide acceptable downlink and uplink performance, e.g. a target cell that is independent of the PBO in the terminal device.

[0108] Figure 10 An apparatus is shown, comprising processing circuitry, such as at least one processor, and at least one memory 40 including computer program code (software) 44, wherein the at least one memory and the computer program code (software) are configured to, with the at least one processor, cause the apparatus to perform the procedures of Figure 3 or any one of its embodiments described above for a terminal device. The apparatus can be for use in a terminal device. The apparatus can be circuitry or electronics implementing some embodiments of the application in a terminal device. The apparatus performing the above described functions can thus be comprised in such a device, e.g. the apparatus can comprise circuitry or a combination of such circuitry, such as a chip, chipset, processor, microcontroller etc. for a terminal device. The processing circuitry can implement a communication controller 30 controlling communication with a cellular network infrastructure in the above described manner. The communication controller can be configured to establish and manage RRC connections and data transmission over the RRC connections.

[0109] The communication controller can include a proximity detection module 39 configured to perform proximity measurements during operation of the terminal device and to detect proximity of an object triggering a PBO event based on the measurements in the manner described above. Depending on the embodiment, the trigger can be responsive to detection of proximity in the serving antenna panel and / or in the non-serving antenna panel. Upon triggering a PBO event, the proximity detection module can cause the neighbor cell measurement circuitry 37 to perform additional neighbor cell measurements for handover of the terminal device. The neighbor cell measurement circuitry 37 can then measure downlink signals received from the neighboring cells detected by the antenna panels and generate the above-described measurement report including the neighbor cell measurement data. As described above, the neighbor cell measurement circuitry can include in the measurement report a PBO metric for each reported non-serving cell. As described above, the PBO metric can be indicative of PBO of the antenna module capable of detecting the non-serving cell.

[0110] The PBO event can also cause the proximity detection module 39 to cause the PBO controller 38 to control PBO of uplink transmission power in the terminal device. The proximity detection module or the PBO controller can insert a delay to enable PBO such that the neighbor cell measurement circuitry 37 has time to take and report measurements and the serving access node has time to react to the detected PBO event by issuing a handover to the terminal device. The PBO controller can output a PBO command to the antenna panel controller 35 to control selection and configuration of one or more serving antenna panels. The antenna panel controller 35 can then reduce transmission power of the serving antenna panel associated with the PBO event.

[0111] Reference Figure 9 The memory 40 can 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 removable memory. The memory 40 can include a configuration database 46 for storing configuration parameters, e.g., characteristics of the warning zone, types of measurements to be taken and reported in relation to PBO events, etc. The memory 40 can also store the above-described mapping table or mapping database 48 defining PBO metrics for various proximities or proximity ranges.

[0112] The apparatus can also include a communication interface 42 including hardware and / or software for providing the apparatus with radio communication capabilities with one or more access nodes, as described above. The communication interface 42 can include hardware and software needed to enable radio communication over a radio interface, e.g., according to the specifications of the LTE or 5G radio interface.

[0113] The apparatus can also include an application processor 32 that executes one or more computer program applications that generate a need to transmit and / or receive data through the communication controller 30. The application processor can form an application layer of the apparatus. The application processor can execute computer programs that form the main functionality of the apparatus. For example, if the apparatus is a sensor device, the application processor can execute one or more signal processing applications to process measurement data acquired from one or more sensor heads. If the apparatus is a computer system of a vehicle, the application processor can execute media applications and / or autonomous driving and navigation applications. The application processor can generate data to be transmitted in a wireless network.

[0114] As used in this application, the term "circuitry" refers to all of one or more circuits, such as, for example, a sole circuit or a combination of circuits, which work together to produce the desired result. For example, the term "circuitry" as used in this application can include one or more processors, such as a processor core, working in combination to produce the desired result. As another example, the term "circuitry" as used in this application can include one or more processors, such as a processor core, working in combination with software and / or firmware to produce the desired result.

[0115] This definition of "circuitry" applies to the use of this term throughout this application. As another example, as used in this application, the term "circuitry" would also cover an implementation in only an analog circuit (or a combination of only analog circuits) and / or an implementation in only a digital circuit (or a combination of only digital circuits). As yet another example, as used in this application, the term "circuitry" would also cover a system-on-a-chip implementation that is a combination of both analog and digital circuitry, such as an implementation that includes both a general- purpose processor (e.g., a microprocessor or microcontroller) and a digital signal processor. Figures 3-4 The processes or methods depicted in any embodiment or described herein can also be performed in the form of one or more computer processes defined by one or more computer programs. A computer program can be in source code form, object code form, or in some intermediate form, and the computer program can be stored in some sort of carrier, which can be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, electrical carrier signal, telecommunications signal, and software distribution package, for example. A computer program may

[0116] The embodiments described herein are applicable in the wireless networks defined above, but also in other wireless networks. The protocols used, specifications of the wireless networks, and their network elements are under rapid development. Such development can require additional changes to the described embodiments. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. The embodiment is not limited to the examples described above but can vary within the scope of the claims.

Claims

1. An apparatus for a terminal device, comprising means for: detecting a need for uplink transmission power reduction in a serving antenna panel of the terminal device, wherein the uplink transmission power reduction comprises a power back-off caused by a maximum permissible exposure limit; in response to the detecting, performing at least one measurement associated with: at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; reporting, to an access node of a serving cell: the at least one measurement; and the need for uplink transmission power reduction, wherein the at least one measurement comprises a measurement associated with uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel; wherein the at least one measurement comprises a measurement of at least one of: a signal strength or a signal quality of a downlink signal received from the at least one non-serving cell; and reporting, to the access node of the serving cell, a metric associated with uplink transmission power of the at least one non-serving cell and / or the at least one non-serving antenna panel, wherein the metric is indicative of the power back-off associated with the maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel.

2. The apparatus of claim 1, wherein the means are configured to report the metric together with a measured downlink signal strength indicator or a measured downlink signal quality indicator of the at least one non-serving cell.

3. The apparatus of claim 1 or 2, wherein the means are configured to perform the at least one measurement and report the at least one measurement prior to the uplink transmission power reduction.

4. An apparatus for an access node, comprising means for: receiving, from a terminal device connected to the access node, a measurement report comprising measurement data related to at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device, wherein the measurement data comprises a measurement associated with uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel; wherein the measurement data is indicative of a signal strength or a signal quality of a downlink signal received by the terminal device from the at least one non-serving cell, and the measurement report further comprises an indication of a need for uplink transmission power reduction in the terminal device, wherein the uplink transmission power reduction comprises a power back-off caused by a maximum permissible exposure limit, wherein the indication comprises at least one information element indicating uplink transmission power of the terminal device in the at least one non-serving cell and / or in the at least one non-serving antenna panel, wherein the at least one information element is indicative of the power back-off associated with the maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel; and the measurement report further comprises an indication of a need for uplink transmission power reduction in the terminal device, wherein the uplink transmission power reduction comprises a power back-off caused by a maximum permissible exposure limit, wherein the indication comprises at least one information element indicating uplink transmission power of the terminal device in the at least one non-serving cell and / or in the at least one non-serving antenna panel, wherein the at least one information element is indicative of the power back-off associated with the maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel; and performing a handover decision for the terminal device based on the measurement data and the indication.

5. The apparatus of claim 4, wherein the means are configured to prevent handover to a non-serving cell or non-serving antenna panel associated with the uplink transmission power reduction.

6. The apparatus of claim 4 or 5, wherein the means are configured to handover the terminal device to a non-serving cell or non-serving antenna panel that is independent of the uplink transmission power reduction.

7. A method for communication, comprising: detecting, by a terminal device, a need for uplink transmission power reduction in a serving antenna panel of the terminal device, wherein the uplink transmission power reduction comprises a power back-off resulting from a maximum permissible exposure limit; in response to the detecting, performing at least one measurement associated with: at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; reporting, by the terminal device to an access node of a serving cell, the at least one measurement and the need for uplink transmission power reduction, wherein the at least one measurement comprises a measurement associated with uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel; wherein the at least one measurement comprises a measurement of at least one of: a signal strength or a signal quality of a downlink signal received from the at least one non-serving cell; wherein the at least one measurement comprises a measurement of at least one of: a signal strength or a signal quality of a downlink signal received from the at least one non-serving cell; and reporting, by the terminal device to the access node of the serving cell, a metric associated with uplink transmission power of the at least one non-serving cell and / or the at least one non-serving antenna panel, wherein the metric is indicative of the power back-off associated with the maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel.

8. The method of claim 7, wherein the terminal device reports the metric together with a measured downlink signal strength indicator or a measured downlink signal quality indicator of the at least one non-serving cell.

9. The method of claim 7 or 8, wherein the terminal device performs the at least one measurement and reports the at least one measurement prior to the uplink transmission power reduction.

10. A method for communication, comprising: receiving, by an access node, a measurement report from a terminal device connected to the access node, the measurement report comprising measurement data related to at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device, wherein the measurement data comprises a measurement associated with uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel; wherein the measurement data is indicative of a signal strength or a signal quality of a downlink signal received by the terminal device from the at least one non-serving cell, and The measurement report further comprises an indication of a need for uplink transmission power reduction in the terminal device, and wherein the uplink transmission power reduction comprises a power back-off caused by a maximum permissible exposure limit, wherein the indication comprises at least one information element indicating an uplink transmission power of the terminal device in the at least one non-serving cell and / or in the at least one non-serving antenna panel, wherein the at least one information element indicates the power back-off associated with the maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel; and performing, by the access node, a handover decision for the terminal device based on the measurement data and the indication.

11. The method according to claim 10, wherein the access node prevents a handover to a non-serving cell or non-serving antenna panel associated with the uplink transmission power reduction.

12. The method according to claim 10 or 11, wherein the access node hands over the terminal device to a non-serving cell or non-serving antenna panel not associated with the uplink transmission power reduction.

13. A computer program product embodied on a computer readable medium and comprising computer program code readable by a computer, wherein the computer program code configures the computer to perform a computer process comprising: detecting, in a terminal device, a need for uplink transmission power reduction in a serving antenna panel of the terminal device, wherein the uplink transmission power reduction comprises a power back-off caused by a maximum permissible exposure limit; in response to the detection, performing at least one measurement associated with at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; reporting, to an access node of a serving cell, the at least one measurement and the need for uplink transmission power reduction, wherein the at least one measurement comprises a measurement associated with an uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel; wherein the at least one measurement comprises a measurement of at least one of: a signal strength or a signal quality of a downlink signal received from the at least one non-serving cell; and reporting, to the access node of the serving cell, a metric associated with an uplink transmission power of the at least one non-serving cell and / or the at least one non-serving antenna panel, wherein the metric indicates the power back-off associated with the maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel.

14. A computer program product embodied on a computer readable medium and comprising computer program code readable by a computer, wherein the computer program code configures the computer to perform a computer process comprising: detecting, in a terminal device, a need for uplink transmission power reduction in a serving antenna panel of the terminal device, wherein the uplink transmission power reduction comprises a power back-off caused by a maximum permissible exposure limit; in response to the detection, performing at least one measurement associated with at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device; reporting, to an access node of a serving cell, the at least one measurement and the need for uplink transmission power reduction, wherein the at least one measurement comprises a measurement associated with an uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel; wherein the at least one measurement comprises a measurement of at least one of: a signal strength or a signal quality of a downlink signal received from the at least one non-serving cell; and reporting, to the access node of the serving cell, a metric associated with an uplink transmission power of the at least one non-serving cell and / or the at least one non-serving antenna panel, wherein the metric indicates the power back-off associated with the maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel. receiving, in an access node, a measurement report from a terminal device connected to the access node, the measurement report comprising measurement data related to at least one non-serving cell of the terminal device and / or at least one non-serving antenna panel of the terminal device, wherein the measurement data comprises measurements associated with uplink transmission power in the at least one non-serving cell and / or the at least one non-serving antenna panel; wherein the measurement data is indicative of a signal strength or a signal quality of a downlink signal received by the terminal device from the at least one non-serving cell, and the measurement report further comprises an indication of a need for uplink transmission power reduction in the terminal device, wherein the uplink transmission power reduction comprises a power back-off caused by a maximum permissible exposure limit, wherein the indication comprises at least one information element, the at least one information element being indicative of an uplink transmission power of the terminal device in the at least one non-serving cell and / or in the at least one non-serving antenna panel, wherein the at least one information element is indicative of the power back-off, the power back-off being associated with the maximum permissible exposure limit of the non-serving cell and / or the non-serving antenna panel; and performing, based on the measurement data and the indication, a handover decision for the terminal device.

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