Controlling Radio Frequency Transmission in a Cellular System

Abstract

This document discloses a solution for controlling radio transmissions in a cell of a cellular communication system. According to one aspect, a method includes: determining a set of cells in a sector having a spatially overlapping coverage area, wherein the set of cells includes at least a first cell and a second cell; determining a maximum total radiation level of the sector; determining a priority for each cell in the set of cells such that the first cell has a higher priority than the second cell; and allocating a parameter indicating a maximum radiation level in the respective cell to each cell in the set of cells based on the maximum total radiation level and the priority, wherein the allocation is performed such that a smaller power reduction from the maximum transmission power is allowed for the first cell than for the second cell.

Description

Technical Field

[0001] The various embodiments described herein relate to the field of wireless communications and, in particular, to controlling radio transmissions in a cell of a cellular communication system. Background Art

[0002] As new radio access technologies evolve on top of existing radio access technologies, radio transmissions caused by various radio transmitters are bound to increase. To limit the amount of radio transmissions, regulations for radio transmissions have been designed. Operators of cellular communication systems are given parameters that define the maximum transmission power or the effective (isotropic) radiated power (EIRP) for each spatial region, such as a cell or a sector of a cellular system. Summary of the Invention

[0003] The independent claims define some aspects of the invention.

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

[0005] Embodiments and features described in this specification that do not fall within the scope of the independent claims (if any) are to be construed as useful examples for understanding the various embodiments of the invention. The independent claims define some aspects of the present disclosure.

[0006] According to one aspect, there is provided an apparatus for controlling radio transmissions in a cell of a cellular communication system, comprising: at least one processor; and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform the following operations: determining a set of cells in a sector having a spatially overlapping coverage area, wherein the set of cells includes at least a first cell and a second cell; determining a maximum total radiation level of the sector; determining a priority for each cell in the set of cells such that the first cell has a higher priority than the second cell; and allocating a parameter indicating a maximum radiation level in the corresponding cell to each cell in the set of cells based on the maximum total radiation level and the priority, wherein the allocation is performed such that a smaller power reduction from the maximum transmission power is allowed for the first cell than for the second cell.

[0007] In one embodiment, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform the following operations: determining a current radiation level for each cell in the set of cells and further performing the allocation based on the current radiation level of each cell.

[0008] In one embodiment, each cell in the cell set includes a plurality of segments, and the at least one memory and computer program code are further configured to cause the device, with the at least one processor, to perform the following operations: determine the current radiation level of each segment, and select the current radiation level of the segment with the highest radiation level in the corresponding cell as the current radiation level of each cell.

[0009] In one embodiment, the at least one memory and computer program code are further configured to cause the device, with the at least one processor, to perform the following operations: determine the margin between the sum of the current radiation levels and the maximum total radiation level, allocate the margin to the cells in the cell set according to the determined current radiation levels and the priority ranking, and adjust the parameters of the cells in the cell set according to the allocation.

[0010] In one embodiment, the current radiation level is the measured effective radiation power, and wherein the parameter is a power reduction factor for reducing the maximum transmission power in the cell.

[0011] In one embodiment, the at least one memory and computer program code are configured to cause the device, with the at least one processor, to perform the following operations: allocate the maximum total radiation level to the cells in the cell set when allocating the parameters, and rebalance the allocation of the maximum total radiation level among the cells in the cell set by changing the parameters of at least two cells in the cell set.

[0012] In one embodiment, the first cell is configured to operate according to a first radio access technology, and the second cell is configured to operate according to a second radio access technology different from the first radio access technology, and wherein the priority ranking is based on the radio access technology, such that the first radio access technology providing a higher quality of experience or a higher quality of service is prior to the second radio access technology providing a lower quality of experience or a lower quality of service.

[0013] In one embodiment, the first cell is a primary cell of the first radio access technology, and the second cell is a secondary cell of the first radio access technology, and wherein the at least one primary cell is prior to the at least one secondary cell.

[0014] According to one aspect, there is provided a computer-implemented method for controlling radio transmission in a cell of a cellular communication system, comprising: determining a set of cells in a sector having a spatially overlapping coverage area, wherein the set of cells includes at least a first cell and a second cell; determining a maximum total radiation level of the sector; determining a priority for each cell in the set of cells such that the first cell has a higher priority than the second cell; and allocating a parameter indicating a maximum radiation level in the corresponding cell to each cell in the set of cells based on the maximum total radiation level and the priority, wherein the allocation is performed such that a smaller power reduction from the maximum transmission power is allowed for the first cell than for the second cell.

[0015] In one embodiment, the method further comprises: determining a current radiation level for each cell in the set of cells, and further performing the allocation based on the current radiation level of each cell.

[0016] In one embodiment, each cell in the set of cells includes a plurality of segments, and the method further comprises: determining a current radiation level for each segment, and selecting the current radiation level of the segment having the highest radiation level in the corresponding cell as the current radiation level of each cell.

[0017] In one embodiment, the method further comprises: determining a margin between the sum of the current radiation levels and the maximum total radiation level, allocating the margin to the cells in the set of cells according to the determined current radiation levels and priority ranking, and adjusting the parameters of the cells in the set of cells according to the allocation.

[0018] In one embodiment, the current radiation level is the measured effective radiation power, and the parameter is a power reduction factor for reducing the maximum transmission power in the cell.

[0019] In one embodiment, when allocating the parameter, the maximum total radiation level is allocated to the cells in the set of cells, and the method further comprises: rebalancing the allocation of the maximum total radiation level among the cells in the set of cells by changing the parameters of at least two cells in the set of cells.

[0020] According to one aspect, there is provided a computer program product embodied on a computer-readable medium and including computer-readable computer program code, wherein the computer program code configures a computer to perform a computer process for controlling radio transmissions in a cell of a cellular communication system, the process including: determining a set of cells having a spatially overlapping coverage area in a sector, wherein the set of cells includes at least a first cell and a second cell; determining a maximum total radiation level of the sector; determining a priority for each cell in the set of cells such that the first cell has a higher priority than the second cell; and allocating, based on the maximum total radiation level and the priority, a parameter indicating a maximum radiation level in each cell in the set of cells, wherein the allocation is performed such that a smaller power reduction from a maximum transmission power is allowed for the first cell than for the second cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Embodiments are described below by way of example only with reference to the drawings, in which:

[0022] Figure 1 and Figure 2 illustrates a wireless communication scenario to which some embodiments of the present invention may be applied;

[0023] Figure 3 illustrates a process for controlling a maximum radiation level in a cell according to an embodiment;

[0024] Figure 4 illustrates an embodiment of a process for controlling a radiation level within a margin to a maximum total radiation level of a sector;

[0025] Figure 5 illustrates an embodiment of a process for rebalancing maximum radiation levels in cells of a sector; and

[0026] Figure 6 illustrates a block diagram of the structure of an apparatus according to an embodiment. DETAILED DESCRIPTION

[0027] The following embodiments are examples. Although the present specification may refer to "one", "a" or "some" embodiments in several places, this does not necessarily mean that each such reference refers to the same embodiment(s) or that the feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments. Further, the words "comprising" and "including" should be understood not to limit the described embodiments to only the features that have been mentioned, and such embodiments may also include features / structures that have not been specifically mentioned.

[0028] 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 these embodiments can be applied, without limiting the embodiments to such an architecture. Those skilled in the art will recognize that by appropriately adjusting parameters and processes, these embodiments can also be applied to other types of communication networks having suitable components. Some examples of other options for suitable systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, the same as E-UTRA), Wireless Local Area Network (WLAN or WiFi), Worldwide Interoperability for Microwave Access (WiMAX), Bluetooth®, Personal Communications Service (PCS), ZigBee®, Wideband Code Division Multiple Access (WCDMA), systems using Ultra-Wideband (UWB) technology, sensor networks, Mobile Ad-hoc Networks (MANET), and Internet Protocol Multimedia Subsystem (IMS) or any combination thereof.

[0029] Figure 1 An example of a simplified system architecture is depicted, which shows only some elements and functional entities (all logical units), and their implementation may be different from the one shown. Figure 1 The connections shown in are logical connections; the actual physical connections may be different. It will be apparent to those skilled in the art that the system generally also includes other functions and structures in addition to Figure 1 the functions and structures shown in.

[0030] However, these embodiments are not limited to the systems given as examples, but those skilled in the art can apply the solution to other communication systems provided with the necessary properties.

[0031] Figure 1 The example of shows a part of an exemplary radio access network.

[0032] Figure 1 Terminal devices or user equipments 100 and 102 are shown, which are configured to make a wireless connection with an access node (such as, (e / g)NodeB) 104 providing the cell on one or more communication channels in the cell. (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 the uplink or reverse link, and the physical link from the (e / g)NodeB to the user equipment is called the downlink or forward link. It should be appreciated that (e / g)NodeB or their functions can be implemented by using any entity such as a node, host, server, or access point suitable for such use.

[0033] A communication system typically includes more than one (e / g) NodeB. In this case, the (e / g) NodeBs can also be configured to communicate with each other via wired or wireless links designed for this purpose. These links can be used not only for signaling purposes but also for routing data from one (e / g) NodeB to another (e / g) NodeB. An (e / g) NodeB is a computing device configured to control the radio resources of the communication system coupled thereto. A NodeB can also be referred to as a base station, access point, access node, or any other type of docking device, including a relay station capable of operating in a wireless environment. An (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 that establishes a bi-directional radio link to a user equipment. The antenna unit can include multiple 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 of the user equipment (UE) to an external packet data network, or a Mobility Management Entity (MME), etc.

[0034] A user equipment (also referred to as UE, user equipment, user terminal, terminal device, etc.) illustrates a type of device to which resources on an air interface are allocated and assigned, and thus any feature described herein for a user equipment can be implemented with a corresponding device such as a relay node. An example of such a relay node is a layer 3 relay towards a base station (self-backhauling relay). The 5G specification defines two relay modes: out-of-band relay, where the same or different carriers can be defined for the access link and the backhaul link; and in-band relay, where the same carrier frequency or radio resources are used for both the access and backhaul links. In-band relay can be considered the baseline relay scenario. The relay node is referred to as an Integrated Access and Backhaul (IAB) node. It also has built-in support for multiple relay hops. IAB operation assumes a so-called split architecture that has a CU and multiple DUs. The IAB node contains two separate functions: the DU (Distributed Unit) part of the IAB node, which facilitates the gNB (access node) function in a relay cell, i.e., it acts as the access link; and the Mobile Terminal (MT) part of the IAB node, which facilitates the backhaul connection. The donor node (DU part) communicates with the MT part of the IAB node and it has a wired connection to the CU, which also has a connection to the core network. In a multi-hop scenario, the MT part (sub-IAB node) communicates with the DU part of the parent IAB node.

[0035] A user equipment generally refers to a portable computing device including a wireless mobile communication device operating with or without a subscriber identity module (SIM), including but not limited to the following types of devices: mobile station (mobile phone), smart phone, personal digital assistant (PDA), cellular phone, device using a wireless modem (such as an alarm or measurement device, etc.), laptop and / or touch screen computer, tablet, game console, notebook computer, and multimedia device. It should be appreciated that the user equipment may also be an almost exclusive uplink-only device, an example of which is a camera or video camera that loads images or video clips onto a network. The user equipment may also be a device capable of operating in an Internet of Things (IoT) network, which is a scenario where objects are provided with the ability to transmit data over a network without the need for human-to-human or human-to-computer interaction. The user equipment may also utilize the cloud. In some applications, the user equipment may include small portable devices with a radio part (such as a watch, headphones, or glasses), and the computing is performed in the cloud. The user equipment (or in some embodiments, a layer 3 relay node) is configured to perform one or more of the user equipment functions. The user equipment may also be referred to as a subscriber unit, mobile station, remote terminal, access terminal, user terminal, or user equipment (UE), just to mention a few names or devices.

[0036] The various techniques described herein may also be applied to cyber-physical systems (CPS) (systems of collaborative computing elements that control physical entities). CPS may enable the realization and utilization of a large number of interconnected ICT devices (sensors, actuators, processors, microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems - where the physical systems under discussion have inherent mobility - are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronics transported by humans or animals.

[0037] In addition, although the apparatus has been depicted as a single entity, different cells, processors, and / or memory units may be implemented ( Figure 1 not all shown).

[0038] 5G enables the use of multiple-input multiple-output (MIMO) antennas, beamforming and / or massive MIMO technologies, and many more base stations or nodes than LTE (the so-called small cell concept), which includes macro sites collaborating with smaller stations, and various radio technologies are adopted depending on service requirements, use cases, and / or available spectrum. 5G mobile communications support a wide range of use cases and related applications, including video streaming, augmented reality, different ways of data sharing, and various forms of machine-type applications (such as (massive) machine-type communication (mMTC), including vehicle safety, different sensors, and real-time control. 5G is expected to have multiple radio interfaces, namely below 6 GHz, centimeter wave, and millimeter wave, and is also capable of integrating with existing traditional radio access technologies (such as LTE). At least in the early stage, the integration with LTE can be implemented as a system where macro coverage is provided by LTE, and 5G radio interface access comes from small cells by aggregating 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 6 GHz - centimeter wave, below 6 GHz - centimeter wave - millimeter wave). One of the concepts considered for use in 5G networks is network slicing, where multiple independent and dedicated virtual sub-networks (network instances) can be created within the same infrastructure to run services with different requirements for latency, reliability, throughput, and mobility.

[0039] The current architecture in LTE networks is fully distributed in the radio and is generally fully centralized in the core network. The low-latency application and service requirements in 5G bring content closer to the radio, which leads to local breakout and multi-access edge computing (MEC). 5G enables analysis and knowledge generation to occur at the source of the data. This approach requires leveraging resources that may 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 cellular subscribers for faster response times. Edge computing encompasses a wide range of technologies, such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed peer-to-peer ad hoc networking and processing, which can also be classified as local cloud / fog computing and grid / mesh computing, dew computing, mobile edge computing, microclouds, distributed data storage and retrieval, self-healing autonomous networks, remote cloud services, augmented reality and virtual reality, data caching, the Internet of Things (massive connectivity and / or latency-critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications).

[0040] The communication system is also capable of communicating with other networks 112, such as the public switched telephone network or the Internet, or using the services they provide. The communication network is also capable of supporting the use of cloud services. For example, at least part of the core network operations can be implemented as cloud services (which is depicted by the "cloud" 114 in Figure 1 ). The communication system may also include a central control entity or the like to provide facilities for the networks of different operators to cooperate, for example, in terms of spectrum sharing.

[0041] The edge cloud can be brought into the radio access network (RAN) by leveraging network function virtualization (NFV) and software-defined networking (SDN). Using the edge cloud may mean implementing access node operations at least partly in a server, host, or node operatively coupled to a remote radio head or base station including a radio part. Node operations will also be possible to be distributed among multiple servers, nodes, or hosts. The application of the cloud RAN architecture enables the implementation of RAN real-time functions at the RAN side (in the distributed unit DU 105) and the implementation of non-real-time functions in a centralized manner (in the centralized unit CU 108).

[0042] It should also be understood that the functional distribution between core network operations and base station operations may be different from that of LTE or may not even exist. Some other technological advancements that may be used are big data and all-IP, which may change the way the network is 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 Node B (gNB). It should be appreciated that MEC can also be applied in 4G networks.

[0043] 5G can also enhance or supplement the coverage of 5G services by using satellite communication, for example, by providing backhaul. Possible use cases are to provide service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or for passengers on vehicles, or to ensure the availability of critical communications and future railway, maritime, and / or aviation communications. Satellite communication can utilize geosynchronous earth orbit (GEO) satellite systems and also low earth orbit (LEO) satellite systems, especially mega-constellations (systems in which hundreds (nanosatellites) of satellites are deployed). Each satellite 109 in the mega-constellation can cover several network entities that support satellites and create an on-ground cell. The on-ground cell can be created by ground relay nodes or by gNBs located on the ground or in satellites.

[0044] It will be apparent to those skilled in the art that the depicted system is only an example of a part of a radio access system and, in fact, the system may include multiple (e / g) NodeBs, a user equipment may be able to access multiple radio cells, and the system may also include other devices such as physical layer relay nodes or other network elements, etc. At least one of the (e / g) NodeBs may be a home (e / g) nodeB. Additionally, in the geographical area of a radio communication system, multiple different types of radio cells as well as multiple radio cells may be provided. The radio cells may be macro cells (or umbrella cells), which are large cells, typically having a diameter of up to several tens of kilometers, or smaller cells such as micro cells, femto cells or pico cells. Figure 1 The (e / g) NodeBs may provide any of these types of cells. A cellular radio system may be implemented as a multi-layer network including several types of cells. Generally, in a multi-layer network, one access node provides one type of (one or more) cells and thus multiple (e / g) NodeBs are required to provide such a network structure.

[0045] As described above, modern cellular systems include several cells that cover the same space or geographical area. These cells may employ the same radio access technology (RAT), such as any of the above-described RATs, or may employ various RATs, such as several 3GPP RATs and / or several RATs specified in other forums (such as IEEE). Figure 2 The overlapping RATs are illustrated in more detail. The base station site 210 is illustrated at the center of a plurality of sectors 200, 202, 204 (hexagons in this illustration) provided around the base station site. A sector may be defined as a geographical area in which multiple overlapping cells are provided. The sector may be omni-directional with respect to the base station site 210, or the sector may be in a certain direction from the base station site 210. In the case of using directional antennas, this concept is currently more suitable than the basic concept in which the base station site is at the center of a hexagonal cell. Multiple cells may be provided for coverage within each of the sectors 200 to 204, where the cells may be provided according to various RATs. Some of the cells in the same sector may support the same RAT but at different frequencies. An example of such a situation is where a primary cell and a secondary cell of the same RAT are provided in the same sector for improved capacity and / or coverage (such as a hot spot). In the case of using highly directional beamforming technology, a cell may be covered by multiple radio beams directed from the base station site in different directions, thus providing combined coverage of the cell. Different beams may be transmitted at different transmission power levels (the beams are indicated by the dashed lines on sector 204), thus causing different radiation levels in different segments of the cell and the sector.

[0046] As described in the background art, there are regulatory limits on the maximum radiation level in a spatial area, and an operator of a cellular communication system must necessarily ensure that the maximum radiation level is not exceeded in the coverage area of the cellular communication system. The operator can run a computer-implemented solution for controlling the radiation level in a cell based on radiation measurements in the cell. The radiation level of each cell can be measured according to the transmission power of the radio transmitter in each cell. In the following description, the focus is on the transmission of the access node in the cell. Given the transmission power level in each cell, a direct mapping to the radiation level can be implemented to obtain information about the current radiation level in the cell and in each sector. This method can also be used to distribute the available radiation "resources" to the cells. Figure 3 FIG. illustrates an embodiment of a computer-implemented method for controlling radio transmission in a cell for a sector (e.g., any one of sectors 200 to 204). The method can be implemented by a radiation controller 220 coupled to an access node of a cellular communication system to control the radiation level of the access node.

[0047] Referring to Figure 3 , the computer-implemented process includes: determining (block 300) a set of cells in the sector having a spatially overlapping coverage area, where the set of cells includes at least a first cell and a second cell; determining a maximum total radiation level 320 for the sector; determining (block 302) the priority of each cell in the set of cells such that the first cell has a higher priority than the second cell; and allocating (blocks 304 to 312) to each cell in the set of cells a parameter indicating the maximum radiation level in the corresponding cell based on the maximum total radiation level and the priority, where the allocation is performed such that a smaller power reduction from the maximum transmission power is allowed for the first cell than for the second cell.

[0048] Figure 3 The method of

[0049] Let us refer to Figure 3 The allocation will be described in more detail. Once the priority of the cells in the sector is determined, the allocation can be implemented. A parameter defining the maximum allowable radiation based on the transmission power can be assigned to each cell. In one embodiment, the parameter is a power reduction factor (F that reduces the maximum transmission power of the cell. PR). A power reduction factor can be applied to limit the maximum power of a cell such that the actual transmission power is controlled under the limit set by the power reduction factor. The power reduction factor can be applied by the access node managing the cell to reduce the maximum transmission power of the cell by the amount defined by the power reduction factor. The true maximum transmission power can be defined as the maximum power that the radio transmitter used by the access node of the cell can transmit. The access node can then configure the maximum limited transmission power, which can be defined as the maximum transmission power that the operator has configured for the cell. This may be the same as or lower than the maximum true maximum transmission power. For example, the reason for this difference may be to adjust the coverage area of the cell in order to reduce interference towards adjacent cells. The power reduction factor can then be applied to the maximum limited transmission power to define the transmission power at which the cell is allowed to radiate. If the power reduction factor is set to 0 dB, the cell can transmit up to 100% of its maximum limited transmission power. If the power reduction factor is configured to -3 dB, the cell is only allowed to transmit up to 50% of its maximum limited transmission power, and so on. Another definition of the power reduction factor is a multiplicative factor applied to the time-averaged maximum transmission power in order to obtain its actual maximum from its cumulative distribution function. Then, the actual transmission power in the cell can vary to be lower than the maximum limited transmission power reduced by the power reduction factor.

[0050] The access node managing the cell can use this parameter to define a ceiling for the transmission power and then enforce the transmission in the cell such that the ceiling will not be exceeded. Conventionally, the power reduction factor is defined in decibels (dB) with respect to the maximum transmission power. In block 304, the first cell in the set of cells is selected, and in block 306 its priority level is determined. This parameter can be assigned based on the above principles and based on this priority. Thus, if the priority is high, a higher maximum transmission power (lower power reduction factor) can be allowed for the cell (block 308). On the other hand, if the priority is low, a lower maximum transmission power (higher power reduction factor) can be assigned to the cell (block 310). Thus, the actual value of this parameter that specifies the maximum transmission power is bound to the priority level, and the actual correlation between different priority levels and the value of this parameter may depend on the design. Some embodiments are described below. Once the parameter value is assigned to the cell, the process can proceed to block 312, where it is determined whether all cells have been assigned a parameter value. If at least one cell has not been assigned a parameter value, the process can return to block 304 to select the next cell. Otherwise, the process can end.

[0051] Priority can be understood as: sorting cells into a certain order according to a criterion that indicates the importance of a cell from a certain perspective. Then, this order can be used to define the allocation of parameters for the maximum allowable radiation level in the cell.

[0052] In one embodiment, the priority sorting is based on radio access technology, such that a first radio access technology that provides a higher quality of experience (QoE) of service quality is prioritized over a second radio access technology that provides a lower QoE of service quality. Thus, a first cell can operate according to the first radio access technology, while a second cell operates according to the second radio access technology. Quality of experience (QoE) and quality of service (QoS) can be defined based on the characteristics of the cellular access service provided by the cell. Conventionally, more advanced evolved versions provide higher QoE and QoS than older evolved versions. Thus, a cell providing 5G access can be prioritized over a cell providing LTE or 3G access. Characteristics affecting QoS typically include data throughput capacity, latency at lower protocol layers (such as at the network layer or below the network layer), the number of faults, etc. Characteristics affecting QoE are: access to a service (such as a mobile broadband service for a certain application such as high-definition video streaming), the operation of such a service from the user's perspective (usually proportional to the effective data rate), and the user-level latency (how long the user has to wait for the start of video playback).

[0053] In one embodiment, the cell set includes at least one primary cell of a first radio access technology and at least one secondary cell of the first radio access technology, and wherein the at least one primary cell is prioritized over the at least one secondary cell. The primary cell can be a macro cell that provides a larger coverage area than the secondary cell. The secondary cell can be a micro cell or a pico cell that provides a hot spot within the coverage area of the primary cell. Thus, the priority sorting can ensure that the primary cell is provided with sufficient margin for radiation to ensure that there are no interruption problems in the cellular network. The primary and secondary cells can support the same RAT.

[0054] Another embodiment combines the embodiments of the above two paragraphs. Thus, one level of prioritization can be the RAT, and the other level can be the order of the cells (primary, secondary, etc.). Thus, the prioritization order in decreasing priority order can be as follows: the primary cell of the first RAT, the primary cell of the second RAT, the secondary cell of the first RAT, and the secondary cell of the second RAT. Thus, the prioritization can ensure that sufficient margin for radiation (transmission power) is provided to all RATs. As defined in the order of priorities, the secondary cells may have a more limited margin. It should be appreciated that the cells may have unique transmission power capabilities, and thus the actual radiation levels may even be significantly different for each cell. For example, even if the secondary cell of the first RAT is prioritized over the primary cell of the second RAT by assigning a lower power reduction factor to the secondary cell of the first RAT, due to the wider coverage area and larger transmission power capabilities, this primary cell will likely still transmit a higher transmission power and have a higher radiation level.

[0055] Yet another embodiment uses the operating frequency as a criterion for prioritization. This may be related to the prioritization based on the primary, secondary, etc. nature of the cells in a scenario where different cells operate at different operating frequencies in a sector.

[0056] In one embodiment, for example, the current radiation level of each cell in the sector is collected from the (one or more) access nodes managing the set of cells, and the allocation is further performed based on the current radiation level of each cell. The current radiation level can be used to determine the total radiation of the sector for comparison with the maximum total radiation level allowed for the sector. The maximum total radiation level can be set by the regulatory limits described above. Thus, information about the current state of radiation in the sector can be obtained, and it can be decided whether there is further margin to the available maximum total radiation level. If there is margin, the radiation controller can adjust the parameter values according to the Figure 4 process. If there is no available margin and instead the measurement results show that the radiation is higher than the maximum total radiation level, the radiation controller can use the Figure 4 process to reduce the parameter values and the radiation level in the cells. If it is found that the measured radiation is substantially at the maximum total radiation level, the radiation controller can use the Figure 5 process to rebalance the radiation levels allowed for the cells.

[0057] In which the cells include as described above in connection with Figure 2In the case of multiple segments with different measured radiation levels as described, the current radiation level of each segment can be determined, and the current radiation level of the segment with the highest radiation level in the cell can be selected as the current radiation level of the cell. This is more feasible than the sum radiation level of the segments because the segments are spatially separated.

[0058] In one embodiment, the radiation level can be measured over a long time interval. The time interval can be one day, one week, one month, or even longer. The time interval can be at least several hours to obtain statistical significance. The current radiation level can be represented in the form of a distribution function (e.g., a cumulative distribution function). The cumulative distribution function can sort the measured radiation levels of the cell in ascending or descending order. The radiation controller can determine a threshold level based on the cumulative distribution function, and this threshold level specifies the minimum target level of the power reduction factor. The threshold level can be set to a level associated with a determined percentile of the cumulative distribution function (e.g., the 100th percentile, the 99th percentile, or the 97th percentile). The percentile X can be understood such that X percent of the measured radiation levels remain below the threshold level. In other embodiments, the threshold level can be set manually or automatically according to another logic, e.g., as determined by the operator of the cellular communication system. This threshold level can be used as a lower limit on how much the maximum radiation level can be reduced for the cell. Since the measurement results and the cumulative distribution function are provided for each cell, different threshold levels can be specified for each cell.

[0059] Now, let's describe Figure 4 the process, which is Figure 3 an embodiment of the process of Figure 4 Referring to Figure 5The process can be used to implement rebalancing of parameter values between cells.

[0060] If the current total radiation level is lower than the maximum total radiation level, the radiation controller can determine that there is a margin between the current total radiation level and the maximum total radiation level, and allocate the margin to the cells in the cell set according to the determined current radiation levels and priority order. In other words, the radiation controller can adjust the parameters of the cells according to the new allocation. Blocks 406 to 412 represent this embodiment. In block 406, the radiation controller can generate a list of cells in decreasing order of priority. The cell with the highest priority can be the first in the list, and the cell with the lowest priority can be the last in the list. Then, in block 408, the first cell (highest priority cell) in the list is selected, and in block 410, the parameter value that defines the maximum radiation level (maximum transmission power) of the cell is changed such that the maximum radiation level of the cell is increased. The upper limit of the increase can be either the maximum total radiation level of the cell or the maximum limited transmission power of the cell, whichever is reached first. When the upper limit is reached, the cell can be removed from the list, and the margin to the maximum total radiation level can be reduced by the increase implemented in block 410. Then, the process can continue to block 412, where it is determined whether there is still a margin to the maximum total radiation level and whether the list is not yet empty. If there is still available margin and the list is not empty, the process returns to block 408, and the next cell in the list is selected. Thus, the parameter value is increased until either the list is empty or the margin is used up, and then the process can end.

[0061] If the current total radiation level in block 404 is higher than the maximum total radiation level, the radiation controller can determine that there is a negative margin between the current total radiation level and the maximum total radiation level, and reduce the maximum radiation level of the cell according to the priority ranking. In other words, the radiation controller can adjust the parameters of the cell according to the thus obtained new allocation of the parameters. Blocks 414 to 420 represent this embodiment. In block 414, the radiation controller can generate a list of cells in increasing order of priority. The cell with the lowest priority can be the first in the list, and the cell with the highest priority can be the last in the list. Then, in block 416, the first cell (the lowest priority cell) in the list is selected, and in block 418, its parameter value that defines the maximum radiation level (maximum transmission power) of the cell is changed such that the maximum radiation level of the cell is reduced. The lower limit of the reduction can be the threshold level (minimum target level) described above or the maximum total radiation level, whichever is reached first. When the lower limit is reached, the cell can be removed from the list, and the negative margin to the maximum total radiation level can be reduced by the reduction implemented in block 418. Then, the process can continue to block 420, where it is determined whether there is still a negative margin remaining to the maximum total radiation level. If there is still a negative margin, the process returns to block 416, and the next cell in the list is selected. Thus, the parameter value is reduced until either the list is empty or the negative margin is removed, and then the process can end. If the list becomes empty before the negative margin has been removed, the radiation controller can redefine at least some of the thresholds to a lower level. Then, blocks 414 to 420 can be repeated.

[0062] In this way, the radiation controller can find the appropriate level for the maximum radiation in each cell such that the performance of the cells is maintained high by assigning higher transmission power limits to lower priority cells and lower transmission power limits to higher priority cells.

[0063] In one embodiment, the current radiation level of a cell used in the embodiments described herein is the measured effective isotropic radiated power (EIRP) or effective radiated power (ERP). For example, ERP is the IEEE standardized definition of the RF power radiated by a radio transmitter. ERP indicates both the actual radiated power and the directivity of the radiated power in a specific direction. ERP can be understood as the input power to the antenna multiplied by the antenna gain, by means of which a radio transmitter can measure the EIRP by measuring its transmission power. EIRP is the hypothetical power that would have to be radiated by an isotropic antenna to give an equivalent signal strength in the direction of the strongest beam of the antenna. The difference between EIRP and ERP is that ERP compares the actual antenna to a half-wave dipole antenna, while EIRP compares the actual antenna to a theoretical isotropic antenna. There is a direct correlation between ERP and EIRP via the gain of the half-wave dipole antenna compared to the isotropic antenna of 1.64 (2.15 dB).

[0064] In one embodiment, when allocating parameters, the radiation controller allocates the maximum total radiation level to the cells in the cell set and rebalances the allocation of the maximum total radiation level among the cells in the cell set by changing the parameters of at least two cells in the cell set. This can be carried out in combination with and after the process of Figure 4 or carried out as an independent process. Figure 5 An embodiment of this rebalancing is illustrated in the flowchart of Figure 5 . Referring to

[0065] In response to this detection, the radiation controller then generates, in block 502, a list of cells for which its maximum allowed radiation will be decreased. This list can be generated based on the measured current radiation levels determined in block 400. For example, if the cumulative distribution function of a cell shows that the current radiation level of the cell is significantly lower than the maximum allowed radiation level assigned to the cell, then the cell can be added to the list in block 502. In other words, a margin can be allocated to another cell that will require a higher maximum allowed radiation level. For example, by determining the measured radiation level representing the determined percentile and comparing the determined measured radiation level with the maximum allowed radiation level, a determination can be made based on the cumulative distribution function when the current radiation level of a cell is significantly lower than the maximum allowed radiation level. If there is at least the determined amount (which can be configurable) of difference, then it can be determined that there is available radiation margin. Similar to block 414, the list can be prioritized, where the cell with the lowest priority is the first on the list.

[0066] Additionally, in response to this detection, the radiation controller generates, in block 504, a list of cells for which its maximum allowed radiation will be increased. This list can be generated based on the measured current radiation levels determined in block 400. For example, if the cumulative distribution function of a cell shows that the current radiation level of the cell is at the maximum allowed radiation level assigned to the cell, then the cell can be added to the list in block 504. In other words, the margin of another cell will be allocated to this cell, which requires a higher maximum allowed radiation level. For example, by determining the measured radiation level representing the determined percentile and comparing the determined measured radiation level with the maximum allowed radiation level, a determination can be made based on the cumulative distribution function when the current radiation level of a cell is at the maximum allowed radiation level. If there is less than the determined amount (which can be configurable and / or can be the same amount as in block 502) of difference, then it can be determined that the margin is needed for this cell. Similar to block 406, the list can be prioritized, where the cell with the highest priority is the first on the list.

[0067] Once the lists in blocks 502 and 504 are completed, the radiation controller can perform rebalancing of the maximum allowed radiation levels between the cells of the sector in block 506. The radiation controller can pick a first cell from the list generated in block 502 and a first cell from the list generated in block 504, and reduce the power reduction factor (maximum allowed radiation level) of the cell picked from the list in block 502 and increase the power reduction factor (maximum allowed radiation level) of the cell picked from the list in block 504. As described above, there can be a lower limit for the power reduction factor of the cells in the list of block 502 and an upper limit for the power reduction factor of the cells in the list of block 504. The thresholds that define the lower and upper limits for each cell can be determined based on priority, in the same manner as described above in conjunction with Figure 4 the manner described. Thus, the radiation controller can increase the power reduction factor of the cell picked from the list in block 504 up to the upper limit and reduce the power reduction factor of the cell picked from the list in block 502 by the same amount. If the lower limit is reached before the upper limit, the radiation controller can remove the cell from the list in block 502 and select the next cell in that list. When the upper limit is reached, the radiation controller can remove the cell from the list in block 504 and select the next cell in that list. In this way, the process can continue until either list (or both) is empty. Since the radiation limits are only transferred between cells, this change will not affect the total radiation level in the sector. When performing the rebalancing, the corresponding power reduction factor or the corresponding parameter can be applied to the cell.

[0068] It should be appreciated that the rebalancing can also be performed in conjunction with Figure 4 For example, if there is a margin to the maximum total radiation level in the sector, the radiation controller can reduce the maximum transmission power of at least one cell in the sector to perform the rebalancing. Similarly, if there is a negative margin to the maximum total radiation level in the sector, the radiation controller can increase the maximum transmission power of at least one cell in the sector to perform the rebalancing.

[0069] Figure 6 illustrates an apparatus including components for performing the Figure 3 process or any one of the embodiments described above. The apparatus can include at least one processor 10 and at least one memory 20 including computer program code (software) 24, wherein the at least one memory and the computer program code (software) with the at least one processor are configured to cause the apparatus to perform Figure 3The process or any of the embodiments described above. The apparatus can be used in a radiation controller 220 included in the network infrastructure of a cellular communication system. The apparatus can be a circuit or an electronic device implementing some embodiments of the present invention in the radiation controller. Thus, the apparatus for performing the above functions can be included in the radiation controller. For example, the apparatus can include circuits such as chips, chip sets, processors, microcontrollers, or a combination of such circuits for the radiation controller. The radiation controller can be part of an operation and maintenance (O&M) controller, an entity of a self-organizing network (SON), a radio access network intelligent controller (RIC), or another entity that controls the operating parameters of a cellular network.

[0070] 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 include a database or record of the maximum total radiation level 320 of sectors or a plurality of sectors managed by the radiation controller. In addition, the at least one memory 20 can store a database 26 of other configuration parameters required for radiation control (e.g., the priority level of cells in each sector). The (one or more) processors can include subcircuits or submodules defined by physical circuits or a combination of physical circuits and software 24.

[0071] The at least one processor 10 can include a data collector 12 configured to collect the measured current radiation levels in the cells, as described above in connection with block 400. It can also construct the cumulative distribution function described above. The priority setting circuit 17 can be configured to set the priority of each cell in the sector, i.e., perform any of blocks 302, 406, and 414 or 502 and 504. Then, the radiation control circuit 14 can perform the allocation of the maximum allowable radiation level for each cell in the sector based on the priority and, in some embodiments, based on the measured current radiation level. The radiation control circuit 14 can be configured to perform, for example, any of blocks 304 to 312. The radiation control circuit can include a margin controller 18 configured to monitor the current radiation level with respect to the maximum total radiation level and, upon detecting a positive or negative margin, perform Figure 4 a process to reallocate the maximum radiation level for each cell in the sector. The radiation control circuit can include a rebalancing circuit 16 configured to rebalance the maximum radiation levels in response to a changed priority level among the cells of the sector. The rebalancing circuit can be configured to perform Figure 5 a process to reallocate the parameters that define the maximum radiation levels of the cells of the sector.

[0072] The apparatus may further include a communication interface 22, which includes hardware and / or software for providing the apparatus with communication capabilities with an access node that manages cells in a (or more) sectors as described above. The communication interface 22 may include, for example, the hardware and software required to communicate through the required interfaces of a cellular communication system according to the specifications of an LTE or 5G interface.

[0073] As used in this application, the term "circuit" refers to one or more of the following: (a) only hardware circuit implementations, such as those implemented only in analog and / or digital circuits; (b) a combination of circuits and software and / or firmware, such as (if applicable): (i) a combination of (one or more) processors or processor cores; or (ii) a portion of (one or more) processors / software, including (one or more) digital signal processors, software, and at least one memory, which work together to enable the apparatus to perform a specific function; and (c) a circuit, such as (one or more) microprocessors or a portion of (one or more) microprocessors, which requires software or firmware for operation, even if the software or firmware is not physically present.

[0074] This definition of "circuit" applies to the use of the term in this application. As a further example, as used in this application, the term "circuit" will also cover implementations that are only a processor (or processors), or a portion of a processor (e.g., one core of a multi-core processor), and its (or their) accompanying software and / or firmware. The term "circuit" will also cover, for example and if applicable to a particular element: a baseband integrated circuit, an application specific integrated circuit (ASIC), and / or a field programmable gate array (FPGA) circuit for a device according to an embodiment of the present invention.

[0075] Figure 3 The processes or methods described in any of its embodiments may also be implemented in the form of one or more computer processes defined by one or more computer programs. The (one or more) computer programs may be in source code form, object code form, or in some intermediate form, and it may be stored in some carrier, which can be any entity or device capable of carrying the program. Such carriers include transient and / or non-transient computer media, such as recording media, computer memories, read-only memories, electrical carrier signals, telecommunication signals, and software distribution packages. Depending on the required processing capabilities, the computer program may be executed in a single electronic digital processing unit, or it may be distributed among multiple processing units.

[0076] The embodiments described herein are applicable to the wireless network defined above and also to other wireless networks. The protocols, wireless networks, and the specifications of their network elements used are evolving rapidly. Such developments may require additional changes to the described embodiments. Accordingly, all words and expressions should be construed broadly and they are intended to illustrate rather than limit the embodiments. It will be apparent to those skilled in the art that, as technology advances, the concepts of the present invention may be implemented in various ways. The embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. An apparatus for controlling radio transmission in a cell of a cellular communication system, comprising: at least one processor; and at least one memory, including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform the following operations: determine a set of cells having a spatially overlapping coverage area in a sector, wherein the set of cells includes at least a first cell and a second cell; determine a maximum total transmission power level of the sector; determine the priority of each cell in the set of cells such that the first cell has a higher priority than the second cell; and based on the maximum total transmission power level and the priority, allocate a parameter indicating the maximum transmission power level in each cell of the set of cells, wherein the allocation is performed such that the power reduced from the maximum transmission power allowed for the first cell is less than the power reduced from the maximum transmission power for the second cell.

2. The apparatus according to claim 1, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform the following operations: determine the current transmission power level of each cell in the set of cells, and further perform the allocation based on the current transmission power level of each cell.

3. The apparatus according to claim 2, wherein each cell in the set of cells includes a plurality of segments, and wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform the following operations: determine the current transmission power level of each segment, and select the current transmission power level of the segment having the highest transmission power level in the corresponding cell as the current transmission power level of each cell.

4. The apparatus according to claim 2 or 3, wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to perform the following operations: determine the margin between the sum of the current transmission power levels and the maximum total transmission power level, allocate the margin to the cells in the set of cells according to the determined current transmission power levels and the priority order, and adjust the parameters of the cells in the set of cells according to the allocation.

5. The apparatus according to claim 4, wherein the current transmission power level is the measured effective radiated power, and wherein the parameter is a power reduction factor for reducing the maximum transmission power in the cell.

6. The apparatus according to claim 1, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to perform the following operations: allocate the maximum total transmission power level to the cells in the set of cells when allocating the parameters, and rebalance the allocation of the maximum total transmission power level among the cells in the set of cells by changing the parameters of at least two cells in the set of cells.

7. The apparatus according to claim 4, wherein the first cell is configured to operate according to a first radio access technology, and the second cell is configured to operate according to a second radio access technology different from the first radio access technology, and wherein the prioritization is based on the radio access technology such that the first radio access technology providing a higher quality of experience or a higher quality of service has priority over the second radio access technology providing a lower quality of experience or a lower quality of service.

8. The apparatus according to claim 1, wherein the first cell is a primary cell of a first radio access technology, and the second cell is a secondary cell of the first radio access technology, and wherein at least one primary cell has priority over at least one secondary cell.

9. A computer-implemented method for controlling radio transmission in a cell of a cellular communication system, comprising: determining a set of cells in a sector having a spatially overlapping coverage area, wherein the set of cells includes at least a first cell and a second cell; determining a maximum total transmission power level of the sector; determining the priority of each cell in the set of cells such that the first cell has priority over the second cell; and allocating to each cell in the set of cells a parameter indicating a maximum transmission power level in the corresponding cell based on the maximum total transmission power level and the priority, wherein the allocation is performed such that the power allowed to be reduced from the maximum transmission power for the first cell is less than the power allowed to be reduced from the maximum transmission power for the second cell.

10. The computer-implemented method according to claim 9, further comprising: determining the current transmission power level of each cell in the set of cells and further performing the allocation based on the current transmission power level of each cell.

11. The computer-implemented method according to claim 10, wherein each cell in the set of cells includes a plurality of segments, and the method further includes: determining the current transmission power level of each section and selecting the current transmission power level of the section having the highest transmission power level in the corresponding cell as the current transmission power level of each cell.

12. The computer-implemented method according to claim 9 or 10, further comprising: determining a margin between the sum of the current transmission power levels and the maximum total transmission power level, allocating the margin to the cells in the set of cells according to the determined current transmission power levels and the prioritization, and adjusting the parameters of the cells in the set of cells according to the allocation.

13. The computer-implemented method according to claim 10, wherein the current transmission power level is the measured effective radiated power, and wherein the parameter is a power reduction factor for reducing the maximum transmission power in the cell.

14. The computer-implemented method according to claim 9, wherein when allocating parameters, a maximum total transmission power level is allocated to a cell in a set of cells, and the method further comprises: rebalancing the allocation of the maximum total transmission power level among the cells in the set of cells by changing the parameters of at least two cells in the set of cells.

15. A computer program product embodied on a computer-readable medium and including computer-readable computer program code, wherein the computer program code configures a computer to perform a computer process for controlling radio transmission in a cell of a cellular communication system, including: determining a set of cells in a sector having a spatially overlapping coverage area, wherein the set of cells includes at least a first cell and a second cell; determining a maximum total transmission power level of the sector; determining the priority of each cell in the set of cells such that the first cell has priority over the second cell; and Allocating a parameter indicating a maximum transmission power level in each cell of a set of cells based on a maximum total transmission power level and the priority, wherein the allocation is performed such that the power allowed to be reduced from the maximum transmission power in a first cell is less than the power allowed to be reduced from the maximum transmission power in a second cell.

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