Controlling aggregation level of a control channel

Abstract

Example embodiments may be related controlling aggregation level of a control channel in a cellular communication network. A computer-implemented method may comprise: obtaining performance data of a cell of a cellular communication network, the performance data comprising: control channel element utilization of a control channel of the cell, and transmission resource utilization of user data channels of the cell; and setting an upper limit for an aggregation level of the control channel, in response to determining that the control channel element utilization is above a first threshold and that the transmission resource utilization is below a second threshold.

Description

CONTROLLING AGGREGATION LEVEL OF A CONTROL CHANNELTECHNICAL FIELD

[0001] Various example embodiments generally relate to the field of wireless communications. Some example embodiments relate to controlling aggregation level of a control channel based on transmission resource utilization of data channel(s) and control channel element (CCE) utilization of the control channel.BACKGROUND

[0002] Wireless communication may be implemented with a cellular radio network comprising access nodes configured to offer communication services to devices via multiple cells corresponding to certain frequencies and / or geographical coverage areas. Control channels, such as for example a physical downlink control channel (PDCCH), may be used for carrying control data, e.g., downlink scheduling assignments or uplink scheduling grants, to the devices.SUMMARY

[0003] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0004] Example embodiments of the present disclosure provide a cell-specific control channel optimization method for improving transmission resource utilization in a cellular communication network. This and other benefits may be achieved by the features of the independent claims. Further example embodiments are provided in the dependent claims, the description, and the drawings.

[0005] According to a first aspect, method is disclosed. The method may be computer-implemented. The method may comprise: obtaining performance data of a cell of a cellular communication network, the performance data comprising: control channel element utilization of a control channel of the cell, and transmission resource utilization of user data channels of the cell; and setting an upper limit foran aggregation level of the control channel, in response to determining that the control channel element utilization is above a first threshold and that the transmission resource utilization is below a second threshold.

[0006] According to an example embodiment of the first aspect, the aggregation level is indicative of an amount of control channel elements for transmitting control channel data, and wherein transmission robustness of the control channel data is configured to increase along with the aggregation level.

[0007] According to an example embodiment of the first aspect, the method comprises: setting the upper limit for the aggregation level of the control channel, further in response to determining that a number of active users in the cell exceeds a third threshold.

[0008] According to an example embodiment of the first aspect, the method comprises: determining a daily busy period of the cell based on the number of active users in the cell; and determining the transmission resource utilization and the control channel element utilization based the daily busy period over a plurality of days.

[0009] According to an example embodiment of the first aspect, the method comprises: determining the transmission resource utilization based on a median or average of the transmission resource utilization on the daily busy period over the plurality of days; and determining the control channel element utilization based on a median or average of the control channel element utilization on the daily busy period over the plurality of days.

[0010] According to an example embodiment of the first aspect, the control channel is shared by the active users, and wherein the user data channels are configured to carry application data of the active users.

[0011] According to an example embodiment of the first aspect, the upper limit of the aggregation level is lower than a highest current aggregation level of the control channel.

[0012] According to an example embodiment of the first aspect, the method comprises: deactivating the upper limit for the aggregation level of the control channel, in response to determining that the control channel utilization is below a fourth threshold, wherein the fourth threshold is lower than the first threshold.

[0013] According to an example embodiment of the first aspect, the transmission resource utilization comprises uplink transmission resource utilization, and the number of active users comprises a number of active uplink users.

[0014] According to an example embodiment of the first aspect, the method comprises: increasing a share of transmission resources of the control channel allocated to control data associated with uplink transmission, in response to determining that the control channel utilization is above the first threshold and that the uplink transmission resource utilization is below the second threshold.

[0015] According to an example embodiment of the first aspect, the method comprises: further increasing the share of transmission resources of the control channel allocated to control data associated with uplink transmission, in response to determining that that downlink transmission resource utilization of the user data channels of the cell is above the second threshold and that a ratio of the uplink downlink transmission resource utilization and the downlink uplink transmission resource utilization is above a fifth threshold.

[0016] According to an example embodiment of the first aspect, the method comprises: decreasing the share of transmission resources of the control channel allocated to control data associated with uplink transmission, in response to determining that uplink transmission resource utilization of the user data channels of the cell is above the second threshold and that the ratio of the uplink downlink transmission resource utilization and the downlink uplink transmission resource utilization is below a sixth threshold.

[0017] According to an example embodiment of the first aspect, the share of transmission resources of the control channel allocated to control data associated with uplink transmission is configured to be maintained within a maximum value and a minimum value.

[0018] According to an example embodiment of the first aspect, the first threshold is in a range of 70-90 %, the second threshold is in a range of 70-90 %, wherein the third threshold is in a range of 5-20, the fourth threshold is within a range of 40-60 %, the fifth threshold is within a range of 1.1-1.3, the sixth threshold is in a range of 0.7-0.9, wherein the minimum value is in a range of 20-40 %, and / or the maximum value is in a range of 60-80 %.

[0019] According to an example embodiment of the first aspect, the transmission resource utilization comprises a physical resource block utilization, and / or the control channel comprises a physical downlink control channel.

[0020] According to a second aspect, an apparatus may comprise means for performing the method of the first aspect, or any example embodiment thereof.

[0021] According to a third aspect, computer program, a computer program product, or one or more (non-transitory) computer-readable media may comprise program code configured to, when executed by a processor, cause an apparatus at least to perform the method of the first aspect, or any example embodiment thereof.

[0022] According to a fourth aspect, an apparatus may comprise at least one processor; and at least one memory including computer program code; the at least one memory and the computer code configured to, with the at least one processor, cause the apparatus at least to perform the method of the first aspect, or any example embodiment thereof.

[0023] Any example embodiment may be combined with one or more other example embodiments. Many of the attendant features will be more readily appreciated as they become better understood by reference to the following detailed description considered in connection with the accompanying drawings.DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are included to provide a further understanding of the example embodiments and constitute a part of this specification, illustrate example embodiments and together with the description help to understand the example embodiments. In the drawings:

[0025] FIG. 1 illustrates an example of a communication network;

[0026] FIG. 2 illustrates an example of an apparatus configured to practise one or more example embodiments;

[0027] FIG. 3 illustrates an example of control channel structure in time and frequency domain;

[0028] FIG. 4 illustrates an example of extension of control channel data in accordance with aggregation level of a control channel;

[0029] FIG. 5 illustrates an example average transmission resource usage per transmission time interval (TTI) at downlink;

[0030] FIG. 6 illustrates an example average transmission resource usage per transmission time interval (TTI) at uplink;

[0031] FIG. 7 illustrates an example of a method for controlling aggregation level of a control channel;

[0032] FIG. 8 illustrates an example of a method for balancing share of transmission resources of a control channel associated with uplink and downlink transmission;

[0033] FIG. 9 illustrates an example of a workflow for implementing change of aggregation level in a communication network;

[0034] FIG. 10 illustrates an example of a sum of average transmission resource usage per transmission time interval (TTI) at uplink before and after change of aggregation level of a control channel;

[0035] FIG. 11 illustrates an example of a sum of average transmission resource usage per transmission time interval (TTI) at downlink before and after change of aggregation level of a control channel; and

[0036] FIG. 12 illustrates an example of a method for controlling aggregation level of a control channel.

[0037] Like references are used to designate like parts in the accompanying drawings.DETAILED DESCRIPTION

[0038] Reference will now be made in detail to example embodiments, examples of which are illustrated in the accompanying drawings. The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.

[0039] FIG. 1 illustrates an example of a communication network. Communication network 100 may comprise one or more devices, which may be also referred to as client nodes, user nodes, users, or user equipment (UE). An example of a device is UE 110, which may be configured to communicate with one or more access nodes 122, 124, 126 of a radio access network (RAN) 120. Signals transmitted by an access node to UE 110 may be referred to as downlink signals or downlink transmissions. Signals transmitted by UE 110 to an access node may be referred to as uplink signals or uplink transmissions. A signal may be transmitted using one or more logical channels and / or physical channels, for example a control channel such as the physical downlink control channel (PDCCH) or data channels such as the physical downlink shared channel (PDSCH) or the physical uplink shared channel (PUSCH). An access node may be also referred to as an access point or a base station.

[0040] Communication network 100 may be configured for example in accordance with the 4thor 5thgeneration (4G, 5G) digital cellular communication networks, as defined by the 3rdGeneration Partnership Project (3 GPP). In one example, communication network 100 may operate according to 3GPP (4G) LTE (Long-Term Evolution) or 3GPP 5G NR (New Radio). Communication network 100 may hence comprise a cellular communication network, e.g., a cellular radio network. Communication network 100 may comprise a 3 GPP communication network. It is however appreciated that example embodiments presented herein are not limited to these example networks and may be applied in any present or future wireless communication networks, or combinations thereof, for example other type of cellular networks, short-range wireless networks, multicast networks, broadcast networks, or the like. Access nodes 122, 124, 126 of RAN 120 may for example comprise 5thgeneration access nodes (gNB) or 4thgeneration access nodes (eNodeB).

[0041] An access node may be configured to provide communication services within one or more cells, illustrated with dotted circles. A cell may correspond to geographical area(s) covered by signals transmitted by the access node, for example at a particular transmission frequency. A cell may be configured to serve multiple users such as UE 110. For example, access node 122 may be configured to providecommunication services within cell 132 and optionally within one or more other cells. Access nodes 124, 126 may be configured to provide communication services within respective cells.

[0042] Communication network 100 may further comprise a core network 130, which may comprise various network functions (NF) for establishing, configuring, and controlling data communication sessions of users, for example UE 110. The data communication sessions may carry user data on the data channels. The user data may, for example, comprise application data associated with one or more applications executable on UE 110. Communication network 100 may further comprise a network controller 140, which may be responsible of monitoring and / or configuring various operations of RAN 120 and / or core network 130.

[0043] Network controller 140 may be external to core network 130. Even though some operations have been described as being performed by network controller 140, it is understood that similar functions may be alternatively performed by other network device(s) or network function(s) of communication network 100, for example by an access node or a device of core network 130.

[0044] Network controller 140 may be configured to control cells of RAN 120, for example to configure parameter(s) of the control channel and / or the data channel(s). Even though illustrated as being connected to core network 130, network controller 140 may be, alternatively or additionally, configured to directly communicate with access node(s) 122, 124, 126 of RAN 120. Direct transmission or reception of data may comprise transmitting data to the access node(s) without routing the transmitted data via core network 130 (e.g., via network functions of core network 130), or receiving the data from access node(s) 122, 124, 126 without the data being routed via core network 130. Network controller 140 may be for example configured to directly receive performance data, e.g., performance management (PM) data of configuration management (CM) data, from access node(s) 122, 124, 126 or directly transmit to an access node a request for changing configuration of the radio link to UE 110, e.g., the aggregation level of the PDCCH.

[0045] FIG. 2 illustrates an example embodiment of an apparatus 200 configured to perform one or more example embodiments. Apparatus 200 may be for example used to implement network controller 140, device of core network 130,UE 110, or any of access nodes 122, 124, 126. Apparatus 200 may comprise at least one processor 202. The at least one processor 202 may comprise, for example, one or more of various processing devices or processor circuitry, such as for example co-processor(s), microprocessor(s), controller(s), digital signal processor(s) (DSP), processing circuitry with or without an accompanying DSP, or various other processing device(s) including integrated circuit(s) such as, for example, application specific integrated circuit(s) (ASIC), field programmable gate array(s) (FPGA), microcontroller unit(s) (MCU), hardware accelerator(s), special-purpose computer chip(s), or the like.

[0046] Apparatus 200 may further comprise at least one memory 204. The at least one memory 204 may be configured to store, for example, computer program code 206 or the like, for example operating system software and application software. The at least one memory 204 may comprise one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination thereof. For example, the at least one memory 204 may be embodied as magnetic storage device(s) (such as hard disk drive, floppy disk, magnetic tape, etc.), optical magnetic storage device(s), or semiconductor memory (ies) (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.).

[0047] Apparatus 200 may further comprise communication interface 208 configured to enable apparatus 200 to transmit and / or receive information to / from other devices, functions, or entities, for example to / from access nodes of RAN 120 or network functions of core network 130. In one example, apparatus 200 may use communication interface 208 to receive performance data of cell(s) of RAN 120, for example from access node(s) 122, 124, 126 directly, or via core network 130. Apparatus 200 may use communication interface 208 to transmit configuration(s), e.g., aggregation level, or an upper limit thereof, to access node(s), 122, 124, 126. Apparatus 200 may further comprise a user interface 210, for example for configuring apparatus 200 or for providing user output by apparatus 200, such as for example visual and / or audible signal(s), for example by speaker(s), display(s), light(s), or the like.

[0048] When apparatus 200 is configured to implement some functionality, some component and / or components of apparatus 200, such as for example the at least one processor 202 and / or the at least one memory 204, may be configured to implement this functionality. Furthermore, when the at least one processor 202 is configured to implement some functionality, this functionality may be implemented using program code 206 comprised, for example, in the at least one memory 204.

[0049] The functionality described herein may be performed, at least in part, by one or more computer program product components such as for example software components. According to an embodiment, the apparatus comprises a processor or processor circuitry, such as for example microcontroller(s), configured by the program code when executed to execute the embodiments of the operations and functionality described. A computer program, a computer program product, or at least one non-transitory computer-readable medium may therefore comprise instructions for causing, when executed, apparatus 200 to perform the method(s) described herein. Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Array(s) (FPGA), applicationspecific Integrated Circuit(s) (ASIC), application-specific Standard Product(s) (ASSP), System-on-a-chip system(s) (SOC), Complex Programmable Logic Device(s) (CPLD), Graphics Processing Unit(s) (GPU).

[0050] Apparatus 200 comprises means for performing at least one method described herein. In one example, the means comprises the at least one processor 202, the at least one memory 204 including program code 206 configured to, when executed by the at least one processor 202, cause apparatus 200 to perform the method. Apparatus 200 may comprise a computing device such as for example an access point, an access node, a base station, a server, a network device, a network function device, or the like. Although apparatus 200 is illustrated as a single device it is appreciated that, wherever applicable, functions of apparatus 200 may be distributed to a plurality of devices, for example to implement example embodiments as a cloud computing service.

[0051] FIG. 3 illustrates an example of control channel structure in time and frequency domain. As noted above, the physical downlink control channel (PDCCH) is an example of a control channel in downlink direction. Even though some example embodiments have been described using PDCCH as an example of control channel, it is understood that example embodiments of the present disclosure may be applied to any suitable control channel on any suitable protocol layer. PDCCH therefore generally represents a control channel. A control channel may be configured to carry control data, e.g., data for configuring communication via the data channel(s). Each cell may have its own PDCCH channel. PDCCH may be used, for example, to schedule when a user is able to transmit data in downlink or uplink direction. PDCCH may be shared resource and therefore different users may share the PDCCH resources. PDCCH may be therefore sometimes a bottleneck in terms of increasing load in the associated cell. Load or load level of a cell may refer to the amount of user data communicated via the cell considering active users of the cell.

[0052] Mapping of control data and user data to respective data channels may be based on allocation of transmission resources such as physical resource blocks (PRB), which is an example of a set of time-frequency resources. A PRB may comprise time-frequency resource elements (RE). For example, in case of an orthogonal frequency division multiplexing (OFDM) system, one OFDM symbol may comprise a plurality of subcarriers. Each subcarrier may be modulated by a modulation scheme, such as for example quadrature amplitude modulation (QAM) or phase shift keying (PSK).

[0053] A resource element may comprise one subcarrier at one OFDM symbol. A resource element may be therefore configured to carry one modulated symbol. A PRB may comprise a set of resource elements, which may be carried by one or more OFDM symbols. A PRB may therefore comprise a set of time-frequency transmission resources. In general, different load levels of a cell may correspond to different time-frequency transmission resource utilization rates of data channels, an example of which is the PRB utilization. Other types of transmission resource utilization measures, such as for example the load of non-guaranteed bit rate (non- GBR) data traffic, may be alternatively used.

[0054] A resource element group (REG) may comprise a group of REs, for example four REs, for example within one OFDM symbol, and for example occupying consecutive subcarriers. A control channel element (CCE) of the PDCCH may comprise a set of REGs, for example nine REGs. A CCE may comprise a set of REGs in one OFDM symbol, for example over three PRBs, as illustrated in FIG. 3. A CCE may be configured to carry control data control data, for example the PDCCH. In general, a control channel element may be any portion of a control channel configured to carry control data, for example a predetermined amount of transmission resources for transmission of control data. The PRBs may further comprise reference signals, for example cell-specific reference signals corresponding to different antenna ports (e.g., port 0 and port 1), as illustrated in FIG. 3. The reference signals may be used by a receiver for estimating the state of the radio channel and equalizing, demodulating, and decoding received data accordingly.

[0055] FIG. 4 illustrates an example of extension of control channel data in accordance with aggregation level of a control channel. In general, access node 122 may be configured to determine the number of CCEs used for transmission of a particular PDCCH, for example based on the current radio channel conditions. The number of CCEs allocated for transmission of PDCCH data may be dependent on an aggregation level of the PDCCH. In one example, the aggregation level may be equal to the number of CCEs allocated for PDCCH transmission. The increased number of transmission resources enables access node 122 to apply stronger forward error correction (FEC) coding and thereby to increase robustness of PDCCH transmission. In general, the aggregation level may be indicative of the amount of CCEs for transmitting control channel data. The transmission robustness of the control channel data may be configured to increase along with the aggregation level.

[0056] For example, if the PDCCH data is intended for a UE with a good downlink channel, e.g., close to access node 122, access node 122 may be configured to determine to transmit one CCE (cf., FIG. 4a), which is likely to be sufficient under good radio channel conditions. However, access node 122 may be configured to determine to use a higher number of CCEs (cf., FIG. 4b) whentransmitting to a UE with a poor radio channel, e.g., near the cell border. For example, up to eight CCEs may be configured to be transmitted to achieve sufficient robustness. In addition, access node 122 may be configured to adjust the power level of PDCCH based on the radio channel conditions. To minimize the signaling overhead, it may be therefore desirable to have several different control channel message formats configured. For example, each format may be configured to contain the minimum payload (e.g., FEC encoded control channel data) required for a particular scenario.

[0057] In case of dynamic PDCCH OFDM symbol usage, access node 122 may be configured to dynamically change the number of OFDM symbols used for PDCCH, for example depending on the blocking rate. The blocking rate may comprise a ratio of users blocked due to insufficient capacity of the PDCCH channel to the number of all users attempting access at a particular cell. As illustrated in FIG. 3, access node 122 may be configured to extend the PDCCH capacity in time domain by allocating more OFDM symbols to the PDCCH channel, for example by increasing the aggregation level of the PDCCH.

[0058] An example of the relationship between the number of CCEs and aggregation levels in context of ETE is provided in Table 1 :Table 1Columns of the table indicate the number of CCEs with respect to different combinations of bandwidth and the number (#) of PRBs. Rows of the table indicate the number of CCEs for different numbers of OFDM symbols (cf., aggregation levels). According to the table, a maximum of 44 CCEs may be supported by an LTE cell having a bandwidth of 10 MHz. Note however that the aggregation levelmay be user specific. For example, configuring aggregation level 8 (e.g., 8 CCEs) in a 10 MHz cell with three OFDM symbols allocated for the PDCCH means that five users (44 / 8 = 5,5) can be supported per TTI.

[0059] It has been observed that in certain high load conditions, PDSCH or PUSCH resources may not be fully used. This may be the case for example in of LTE800 cells. These data channels may be configured to deliver user data between access node 122 and UE 110. Usage of these data channels may be measured for example by PRB utilization. Ideally, the PRB utilization of the fully loaded cell should be 100 %. Partial utilization might occur most frequently in uplink direction, for example on the PUSCH. This behaviour may be observed for example when a high number of active users are present in a cell. One reason for the partial utilization of the PUSCH is that users may be blocked due to insufficient capacity available at the PDCCH. For example, at uplink the data packets may be so small that it may not be possible to utilize a full TTI by the small packets. This comes combined with the limited capacity on PDCCH. For example, assuming that user data of five users can be scheduled on one TTI, each user consuming 10% of PRBs, the PRB utilization in this TTI would be only 50%. The behaviour of PRB utilization is illustrated in FIG. 4 and FIG. 5 for downlink and uplink, respectively. Each dot represents one time / cell pair. Values of PRB utilization for the different time / cell pairs has been plotted with respect to the number of active users. The number of active users may comprise a number of users considered by communication network 100 to be active, e.g., users configured to send data, for example users currently configured with uplink grant(s) for transmitting PUSCH data.

[0060] It can be observed that in downlink direction, a high number of users may result in high PRB utilization. However, in uplink direction, even very high number of users may result in 50% PRB utilization, that is, 50% of the resources may not be utilized. Example embodiments of the present disclosure enable to improve PRB utilization of data channels of communication network 100, for example by setting an upper limit for the aggregation level of PDCCH. This enables to free capacity of the PDCCH and thereby to increase utilization rate of the data channels.

[0061] FIG. 7 illustrates an example of a method 700 for controlling aggregation level of a control channel. As noted above, the methods disclosed herein may be performed by any suitable device, for example network controller 140, a device of core network 130, or an access node. For simplicity, the operations of FIG. 7 to 9 have been described using network controller 140 as an example of such a device. It is further noted that even though some the example embodiments have been described using PDCCH as an example, similar operations may be generally performed for any type of control channel whose capacity affects the number of users capable of accessing the data channels.

[0062] At operation 701, network controller 140 may obtain performance data of a cell of communication network 100, in this example cell 132 served by access node 122. The performance data may comprise key performance indicators (KPI) of cell 132, such as for example one or more of the following: CCE utilization of the PDCCH, transmission resource (e.g., PRB) utilization in downlink, transmission resource (e.g., PRB) utilization in uplink, or the number of active users (e.g., in uplink and / or downlink direction).

[0063] At operation 702, network controller 140 may determine a daily busy period. Network controller 140 may determine the daily busy period based on the number of active users at cell 132. The daily busy period may for example comprise a busiest hour or hours of over multiple days (e.g., seven says) in terms of the number of active users. For example, network controller 140 may be configured to determine the busiest hour(s) of the day based on an average of the number of active users at different hours of the day over multiple days.

[0064] At operation 703, network controller 140 may determine CCE utilization of PDCCH. Network controller 140 may determine the CCE utilization for example as the ratio between the number of REs used for transmission of PDCCH data (numerator) and the number of REs allocated for the PDCCH (denominator), e.g., the maximum CCE capacity with the configured bandwidth. Network controller 140 may receive this information from access node 122.

[0065] Network controller 140 may determine the CCE utilization based on the median or average of CCE utilization over a time period (e.g., a number of days). Network controller 140 may be configured determine the CCE utilization based ona median or average of the PRB utilization on the daily busy period determined at operation 702. It is however noted that network controller 140 may be configured to, alternatively or additionally, apply instant measurement of the CCE utilization, for example to enable faster control of the aggregation level and thereby to quickly attempt to resolve any resource utilization issues cell 132.

[0066] At operation 704, network controller 140 may determine PRB utilization of data channels(s), for example the PUSCH and / or the PDSCH. Network controller 140 may determine the uplink PRB utilization for example as the ratio between the number of PRBs used for uplink transmissions on PUSCH at cell 132 (numerator) and the number of PRBs available for PUSCH transmissions at cell 132 (denominator). Network controller 140 may determine the downlink PRB utilization as the ratio between the number of PRBs used for downlink transmissions on PDSCH at cell 132 (numerator) and the number of PRBs available for PDSCH transmissions at cell 132 (denominator). Network controller 140 may receive this information from access node 122.

[0067] Similar to CCE utilization, network controller 140 may determine the PRB utilization(s) based on the median or average of the PRB utilization(s) over a time period (e.g., a number of days), for example based on a median or average of the PRB utilization on the daily busy period determined at operation 702.

[0068] Determining the CCE and PRB utilization based on the median or average provides the benefit of improving reliability of the obtained CCE and PRB utilization values. Determining the CCE and PRB utilization considering the busiest hour(s) of a day provides the benefit of further improving reliability of the obtained CCE and PRB utilization values, because the measurements are directed to the hour(s) most likely causing blocking of users due to insufficient PDCCH capacity. It is however noted that network controller 140 may be configured to, alternatively or additionally, apply instant measurement of the PRB utilization, for example to enable faster control of the aggregation level and thereby to quickly attempt to resolve any resource utilization issues cell 132.

[0069] Network controller 140 may be configured to consider transmissions associated with any active users of cell 132, when determining the CCE and PRB utilization values. The PDCCH may be shared by the active users. The PUSCHand / or the PDSCH may be configured to carry application data of the active users. The CCE and PRB utilization values therefore provide information on the balance of the capacity allocated to the PDCCH and the data channels, which enables optimization of the capacity allocated to the PDCCH, e.g., by controlling the aggregation level.

[0070] At operation 705, network controller 140 may determine whether the CCE utilization of cell 132 is above a threshold (e.g., CCE utilization threshold), referred to herein as a first threshold. The first threshold may be in the range of 70- 90 %, for example 80 %. Values within this range have been observed to result in a good balance between capacity allocated for PDCCH and the data channels.

[0071] Network controller 140 may move back to execution of operation 701 to obtain further performance data of the cell, or perform similar operations for another cell, in response to determining that the CCE utilization is not above the first threshold. Network controller 140 may be for example configured to repeat method 700 for particular cell(s), for example periodically or according to a predetermined schedule.

[0072] At operation 706, network controller 140 may be configured to determine whether PRB utilization of data channel(s) of cell 132 is / are below a second threshold (e.g., PRB utilization threshold). The second threshold may be in the range of 70-90 %, for example 80 %. Values within this range have been observed to result in a good balance between capacity allocated for PDCCH and the data channels, e.g., when the first threshold is within the same range. In one example, the first threshold is equal to the second threshold. In this case, the first and second thresholds may be implemented as a single threshold.

[0073] Note that the procedure of FIG. 7 may be performed considering uplink or downlink direction. In case of uplink, network controller 140 may determine whether uplink PRB utilization of cell 132 is below the second threshold. In this case, the number of active users may comprise the number of active uplink users. Alternatively, network controller 140 may determine whether downlink PRB utilization of cell 132 is below the second threshold. In this case, the number of active users may comprise the number of active downlink users.

[0074] Network controller 140 may move back to execution of operation 701 to obtain further performance data of the cell, or perform similar operations for another cell, in response to determining that the PRB utilization is not below the second threshold. Alternatively, network controller 140 may end method 700, at least temporarily.

[0075] Considering the uplink, network controller 140 may be configured to move to execution of operation 707, or operation 708 directly, in response to determining that the CCE utilization is above the first threshold (cf. operation 705) and that the PRB utilization at the uplink is below the second threshold (cf. operation 706). Considering the downlink, network controller 140 may be configured to move to execution of operation 707, or operation 708 directly, in response to determining that the CCE utilization is above the first threshold (cf. operation 705) and that the PRB utilization at the downlink is below the second threshold (cf. operation 706).

[0076] At operation 707, network controller 140 may determine whether the number of active users (e.g., active uplink or downlink users) is above a third threshold (e.g., active user threshold). The third threshold may be in the range of 5- 20, for example set to ten active users. This provides the benefit of enabling to ensure reliability of the CCE and PRB utilization values, when configuring the aggregation level in cell 132.

[0077] At operation 708, network controller 140 may set an upper limit for the aggregation level of the PDCCH. This provides the benefit of enabling to limit the level of redundancy when transmitting PDCCH data and therefore enables the capacity of the PDCCH channel to be shared with a higher number of users. And, enabling more users to access cell 132 also increases the PRB utilization at the data channel(s). Network controller 140 may set the upper limit such that it is lower than the current aggregation level of the PDCCH at cell 132. In case different aggregation levels are configured for different users, network controller 140 may set the upper limit such that it is lower than the highest aggregation level of the current aggregation levels of the PDCCH at cell 132. By setting the upper limit, network controller 140 may ensure that aggregation level of the PDCCH is below or equal to the upper limit at cell 132.

[0078] Considering operations 705 and 706, network controller 140 may be configured to set the upper limit, in response to determining that the CCE utilization is above the first threshold and that the PRB utilization is below the second threshold. Also considering operation 707, setting the upper limit, e.g., based the determinations at operations 705 and / or 706, may be conditioned on the number of active users exceeding the third threshold. Network controller 140 may be therefore configured to set the upper limit, further in response to determining that the number of active users in cell 132 exceeds the third threshold (e.g., in addition to the conditions of operations 705 and 706 being met).

[0079] Considering the uplink, network controller 140 may be configured to set the upper limit, in response to determining that the CCE utilization is above the first threshold and that the uplink PRB utilization is below the second threshold. Considering the downlink, network controller 140 may be configured to set the upper limit, in response to determining that the CCE utilization is above the first threshold and that the downlink PRB utilization is below the second threshold. In both cases, the third threshold on the number of active users, in this case the number of active users on the relevant link (e.g., uplink or downlink) may be applied as described above.

[0080] It is noted that operations 705, 706, and / or 707 may be performed in any suitable order. If one or more of the conditions associated with these operation is / are not met, network controller 140 may move to execution of operation 701, or at least temporarily terminate execution of method 700.

[0081] Various alternative implementations may be construed from the operations of FIG. 7, FIG. 8, and / or FIG. 9. For example, network controller 140 may be configured to terminate, at least temporarily, execution of method 700 after setting the upper limit at operation 708. Alternatively, network controller 140 may be configured to move to execution of operation 709 to determine when to deactivate the upper limit, or to operation 801 of FIG. 8 in order to initiate balancing of PDCCH capacity allocated for control data associated with uplink and downlink transmissions.

[0082] At operation 709, network controller 140 may determine whether the CCE utilization is below a fourth threshold (e.g., deactivation threshold). The fourththreshold may be lower than the first threshold. The fourth threshold may be for example in the range of 40-60 % (e.g., 50 %). Deactivation of the upper limit enables the aggregation level to be freely raised for users in poor radio channel conditions, when there is enough capacity available in the PDCCH. Network controller 140 may continue monitoring the CCE utilization, for example as described with reference to operation 703 after application of the upper limit that was set at operation 708. Optionally, network controller 140 may terminate monitoring of the PRB utilization, in response to setting the limit for the aggregation level. This reduces power consumption while enabling deactivation on the upper limit when desired. Network controller 140 may move to execution of operation 701, remain at execution of operation 709, or move to execution of operation 801, in response to determining that the CCE utilization is not below the fourth threshold.

[0083] At operation 710, network controller 140 may deactivate the upper limit, which was set at operation 708. This may be in response to determining (cf., operation 709) that the CCE utilization is below the fourth threshold. Network controller 140 may for example enable the aggregation level of the PDCCH channel to be determined freely, or at least without the restriction posed by the upper limit. For example, network controller 140 may set the aggregation level to a default aggregation level, in response to deactivating the upper limit. Network controller 140 may move from execution of operation 710 to execution of operation 701, or to terminate execution of method 700, at least temporarily.

[0084] Method 700 enables to control the aggregation level of the PDCCH channel such that less users are blocked due to insufficient amount of transmission resources available at the PDCCH. This enables to improve PRB utilization at data channels, e.g., PUSCH / PDSCH.

[0085] FIG. 8 illustrates an example of a method 800 for balancing share of transmission resources of a control channel associated with uplink and downlink transmission. PDCCH is used again as an example of the control channel.

[0086] Balancing between PDCCH data associated with uplink and downlink transmission may be initially based on a default share (e.g., 50 %) of PDCCH resources allocated to PDCCH data associated with uplink transmissions. For example, half of the PDCCH resources may be allocated to data associated withuplink transmissions and half of the PDCCH resources may be allocated to data associated with downlink transmissions. Control data associated with uplink transmission may comprise configuration data of uplink transmissions, for example transmission parameter(s) (e.g., modulation and / or FEC coding parameters) or allocation of transmission resources (e.g., PRBs) to uplink transmission(s). Control data associated with downlink transmission may comprise configuration data of downlink transmissions, for example similar parameters and / or allocations as at the uplink. Network controller 140 may initiate method 800 for example in response to setting the upper limit at operation 708. It is however noted that operations of method 700 and 800 may be performed in any suitable order, or in parallel, where appropriate. For example, network controller 140 may perform operation(s) of method 800 in parallel, or sequentially, with monitoring the CCE utilization at operation 709 with respect to the fourth threshold for deactivation of the upper limit of the aggregation level.

[0087] At operation 801, network controller 140 may increase the share of PDCCH resources allocated to control data associated with uplink transmission. This may be in response to determining that the CCE utilization is above the first threshold and that the uplink PRB utilization is below the second threshold (cf. operations 705 and 706). The share of PDCCH transmission resources allocated to control data associated with uplink transmission may comprise a ratio between the number of PDCCH resources (e.g., REs) allocated for control data associated with the uplink (numerator) and the total number of PDCCH resources (denominator). Increasing the share of PDCCH resources associated with uplink transmissions may result in decrease of PDCCH resources associated with downlink transmissions. Network controller 140 may be configured to increase the share of PDCCH resources allocated to control data associated with uplink transmissions by a predetermined amount, such as for example by five percentage units at a time.

[0088] At operation 802, network controller 140 may determine whether the downlink PRB utilization is above the second threshold. If yes, network controller 140 may move to execution of operation 803. If not, network controller 140 may move to execution of operation 804. The threshold of operation 802 may be alternatively different from the second threshold. This provides the benefit ofenabling configuration of balancing method 800 such that the balancing is not tied to the same threshold as setting the upper limit for the aggregation level.

[0089] At operation 803, network controller 140 may determine whether the ratio of downlink PRB utilization (numerator) and uplink PRB utilization (denominator) is above a fifth threshold (e.g., an upper utilization ratio threshold). The fifth threshold may be in the range of 1.1-1.3, for example 1.2. If the ratio is above the fifth threshold, network controller 140 may move back to execution of operation 801 to further increase the share of PDCCH resources allocated to control data associated with uplink transmissions.

[0090] Network controller 140 may be configured to iterate operations 801, 802, and 803 to increase the share of PDCCH resources allocated to control data associated with uplink transmissions as long as the conditions of operations 802 and 803 are met. This provides the benefit of enabling to gradually increase the number of uplink users, which may be more critical in terms of achieving desired PRB utilization.

[0091] At operation 804, network controller 140 may determine whether uplink PRB utilization is above the second threshold. If yes, network controller 140 may move to execution of operation 805. If not, network controller 140 may move back to operation 802 to continue monitoring conditions for increasing the share of PDCCH resources allocated to control data associated with uplink transmissions. Alternatively, network controller 140 may move back to execution of method 700, for example at operation 701 or 709, or end execution of method(s) 700, 800, at least temporarily. The threshold of operation 804 may be alternatively different from the second threshold, for example have the same value as at operation 802.

[0092] At operation 805, network controller 140 may determine whether the ratio of downlink PRB utilization (numerator) and uplink PRB utilization (denominator) is below a sixth threshold (e.g., a lower utilization ratio threshold). The sixth threshold may be lower than the fifth threshold. The sixth threshold may be in the range of 0.7-0.9, for example 0.8. If the ratio is above the sixth threshold, network controller 140 may move to execution of operation 806. If not, network controller 140 may move to execution of operation 802, 701, 709, or end execution of method(s) 700, 800, at least temporarily.

[0093] At operation 806, network controller 140 may decrease the share of PDCCH resources allocated to control data associated with uplink transmissions, for example by a predetermined amount such as five percentage units. This may be in response to determining that the uplink PRB utilization of the data channels is above the second threshold, and / or that the ratio of the downlink PRB utilization and the uplink PRB utilization is below a sixth threshold. This provides the benefit of enabling to ensure that sufficient capacity is available at the PDCCH for signalling downlink transmissions.

[0094] When increasing or decreasing the share of PDCCH resources allocated to control data associated with uplink transmissions, network controller 140 may be configured to maintain the share within maximum and minimum values. The minimum value may be in the range of 20-40 %, for example 10 %. The maximum value may be in the range of 60-80 %, for example 70 %. This provides the benefit of enabling to ensure that there is still sufficient capacity for signalling uplink or downlink transmissions, even if the relative share of one of them were changed.

[0095] As noted above, various different combinations of the operations of method 700 and / or method 800 may be applied in different example embodiments. For example, network controller 140 may move to execution of any of operations 701, 709, 802, or to at least temporarily end the procedure, in response to determining that the condition of operation 804 or 805 is not met. From operation 806 network controller 140 may move to execution of operation 804 in order to determine whether to further decrease the share of PDCCH resources allocated to control data associated with uplink transmissions.

[0096] As a numerical example of methods 700 and 800, network controller 140 may be configured to operate as follows:

[0097] Network controller 140 may receive transmission resource (e.g., PRB) utilization at downlink. Network controller 140 may receive transmission resource (e.g., PRB) utilization at uplink. Network controller 140 may receive the number of active users at downlink of cell 132, where and active user may refer to a user that is sending data at cell 132. Network controller 140 may receive the number of active users at uplink of cell 132. Network controller 140 may a value of CCE utilization.

[0098] Network controller 140 may perform activation of the upper limit of the aggregation level as follows: Network controller 140 may select daily busy hour or a number of busiest hours based on the number of active uplink users. Network controller 140 may calculate the median or average of uplink PRB utilization, the number of active uplink users and CCE utilization, for example based on the busy hour(s) of the last seven days. If the median or average of the CCE utilization is above the first threshold of 80 % of the maximum CCE capacity of the configured bandwidth (cf. Table 1), e.g., 44 in case of 10 MHz bandwidth, the median or average PRB utilization is below the second threshold of 80 %, and the number of active uplink users is above the third threshold of 10 users, network controller 140 may set the upper limit for the aggregation level to 4 (e.g., from current level(s) of 8 and / or 16). In case of downlink direction, network controller 140 may use similar conditions, but use the number of active downlink users and downlink PRB utilization instead of active uplink users and uplink n PRB utilization, respectively.

[0099] Network controller 140 may perform the deactivation of the upper limit as follows: If the median of average of the CCE utilization is below the fourth threshold of 50 % of the maximum CCE capacity of that bandwidth, network controller 140 may deactivate the upper limit and set the aggregation level to a default aggregation level.

[0100] Network controller 140 may perform balancing between allocation of PDCCH resources to control data associated with uplink and downlink transmissions as follows: Network controller 140 may initially balance the PDCCH capacity by setting the balancing share parameter equal to 50 %, indicating that both uplink and downlink directions are allocated the same amount of PDCCH resources. When setting the upper limit for the aggregation level, network controller 140 may change balancing share parameter to indicate allocation of 65% PDCCH resources to control data associated with uplink transmissions.

[0101] If the upper limit has been set and downlink PRB utilization is above the second threshold of 80 %, and further if the ratio of PRB utilization at downlink and uplink (PRB UTIL DL / PRB UTIL UL) is above the fifth threshold of 1.25, network controller 140 may add weight 0.05 to the share of PDCCH resources allocated to control data associated with uplink transmissions (e.g., from 0.65 to0.7). However, if uplink PRB utilization is above the second threshold of 80 %, and further if the ratio of PRB utilization at downlink and uplink (PRB UTIL DL / PRB UTIL UL) is below the sixth threshold of 0.8, network controller 140 may add weight 0.05 to the share of PDCCH resources allocated to control data associated with downlink transmissions. This decreases the share of PDCCH resources allocated to control data associated with uplink transmissions accordingly (e.g., from 0.65 to 0.6). Regardless of any changes to the share of PDCCH resources, network controller 140 may maintain the share of PDCCH resources allocated to control data associated with uplink transmissions between the maximum and minimum values of value 0.75 and minimum value 0.30.

[0102] It has been observed that it is possible to improve data channel utilization of a cell for example from 50-60 % to close to the maximum, e.g., 90-95 %. However, as there may be a minor negative impact on RLC re-transmissions the users in bad radio channel conditions, network controller 140 may be configured to perform the method(s) for selected cells and not throughout communication network 100. Hence algorithms have been provided for detecting the cells that are likely to benefit from limiting the PDCCH aggregation level. Furthermore, the example embodiments enable optimizing balancing between uplink and downlink users are balanced on the PDCCH.

[0103] FIG. 9 illustrates an example of a workflow for implementing change of aggregation level in a communication network.

[0104] At operations 901 and 902, network controller 140 may receive and / or process configuration management (CM) data and / or KPI data of a cell, for example to determine the input parameters for controlling the aggregation level. As described above, the input parameters may comprise one or more of the following: CCE utilization, PRB utilization (e.g., at uplink and / or downlink), or number of active users (e.g., at uplink and / or downlink). Operation(s) 901 and / or 902 may be referred to as data retrieval.

[0105] At operation 903, network controller 140 may determine whether the aggregation level (AGG) is to be changed, for example by setting the upper limit. If yes, network controller 140 may change the aggregation level, for example asdescribed with reference to FIG. 7, and move to execution of operation 904. If not, network controller 140 may move to execution of operation 905.

[0106] At operation 904, network controller 140 may determine whether to perform balancing of the PDCCH resources allocated to control data associated with uplink and downlink transmissions. If yes, network controller 140 may perform balancing between PDCCH resources allocated to control data associated with uplink and downlink, for example as described with reference to FIG. 8, and move to execution of operation 905. If not, network controller 140 may move directly to execution of operation 905 without performing the balancing.

[0107] At operation 905, network controller 140 may determine whether to perform a rollback to previous configuration. Network controller 140 may perform the rollback for example in response to determining that the change(s) at operations cause KPIs to degrade, e.g., a number of re-transmissions (e.g., radio link control (RLC) layer re-transmissions) to increase, for example by a configured amount or above a threshold. If network controller 140 determined to perform rollback, network controller 140 may deactivate the upper limit. Network controller 140 may for example revert back to using a default aggregation level. If not, network controller 140 may move to execution of operation 906 without performing the rollback.

[0108] At operation 906, network controller 140 may create a configuration file, for example an extensible markup language (XML) file, comprising changes to aggregation levels of one or more users at one or more cells of communication network 100. Network controller 140 may provide the configuration file to RAN 120, e.g., access node(s) thereof, for implementation of the change.

[0109] FIG. 10 and FIG. 11 illustrate examples of the sum of average transmission resource usage per transmission time interval (TTI) at uplink and downlink before and after change of aggregation level of a control channel. The vertical line represents the time when the upper limit for the aggregation level was applied. It can be seen from FIG. 10, that after setting the upper limit for the aggregation level, uplink transmission resource utilization has significantly increased. Even downlink transmission resource utilization has improved, as can beseen in FIG. 11. It is further noted that these figures illustrate overall results for cells of a test cluster. The improvement may be more significant in individual cells. [001 10] FIG. 12 illustrates an example of a method for controlling an aggregation level of a control channel. The method may be at least partially computer implemented. The method may be implemented by network controller 140, an access node, or in general any network device.[001 1 1 ] At 1201, the method may comprise obtaining performance data of a cell of a cellular communication network, the performance data comprising: control channel element utilization of a control channel of the cell, and transmission resource utilization of user data channels of the cell.[001 1 2] At 1202, the method may comprise setting an upper limit for an aggregation level of the control channel, in response to determining that the control channel element utilization is above a first threshold and that the transmission resource utilization is below a second threshold.[001 1 3] Further features of the method directly result for example from the functionalities of network controller 140, access node(s) 122, 124, 126 or in general apparatus 200, as described throughout the specification and in the appended claims, and are therefore not repeated here. Different variations of the method may be also applied, as described in connection with the various example embodiments. [001 14] An apparatus, such as for example a network device configured to implement one or more network functions or entities, may be configured to perform or cause performance of any aspect of the method(s) described herein. Further, a computer program or a computer program product may comprise instructions for causing, when executed, an apparatus to perform any aspect of the method(s) described herein. Further, an apparatus may comprise means for performing any aspect of the method(s) described herein. According to an example embodiment, the means comprises at least one processor, and memory including program code, the at least one processor, and program code configured to, when executed by the at least one processor, cause performance of any aspect of the method(s). In general, computer program instructions may be executed on means providing generic processing functions. Such means may be embedded for example in computer(s), server(s), or the like. The method(s) may be thus computer-implemented, forexample based algorithm(s) executable by the generic processing functions, an example of which is the at least one processor 202.[001 1 5] Any range or device value given herein may be extended or altered without losing the effect sought. Also, any embodiment may be combined with another embodiment unless explicitly disallowed.[001 1 6] Although the subject matter has been described in language specific to structural features and / or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims.[001 1 7] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item may refer to one or more of those items.[001 1 8] The steps or operations of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the scope of the subject matter described herein. Aspects of any of the example embodiments described above may be combined with aspects of any of the other example embodiments described to form further example embodiments without losing the effect sought.[001 1 9] The term 'comprising' is used herein to mean including the method, blocks, or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements. [001 20] Although subjects may be referred to as ‘first’ or ‘second’ subjects, this does not necessarily indicate any order or importance of the subjects. Instead, such attributes may be used solely for the purpose of making a difference between subjects.[001 21 ] It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in theart. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from scope of this specification.

Claims

CLAIMS1. A computer-implemented method, comprising: obtaining performance data of a cell of a cellular communication network, the performance data comprising: control channel element utilization of a control channel of the cell, and transmission resource utilization of user data channels of the cell; and setting an upper limit for an aggregation level of the control channel, in response to determining that the control channel element utilization is above a first threshold and that the transmission resource utilization is below a second threshold.

2. The method according to claim 1, wherein the aggregation level is indicative of an amount of control channel elements for transmitting control channel data, and wherein transmission robustness of the control channel data is configured to increase along with the aggregation level.

3. The method according to claim 1 or 2, further comprising: setting the upper limit for the aggregation level of the control channel, further in response to determining that a number of active users in the cell exceeds a third threshold.

4. The method according to claim 3, further comprising: determining a daily busy period of the cell based on the number of active users in the cell; and determining the transmission resource utilization and the control channel element utilization based the daily busy period over a plurality of days.

5. The method according to claim 4, further comprising: determining the transmission resource utilization based on a median or average of the transmission resource utilization on the daily busy period over the plurality of days; anddetermining the control channel element utilization based on a median or average of the control channel element utilization on the daily busy period over the plurality of days.

6. The method according to any of claims 3 to 5, wherein the control channel is shared by the active users, and wherein the user data channels are configured to carry application data of the active users.

7. The method according to any of claims 1 to 6, wherein the upper limit of the aggregation level is lower than a highest current aggregation level of the control channel.

8. The method according to any of claims 1 to 7, further comprising: deactivating the upper limit for the aggregation level of the control channel, in response to determining that the control channel utilization is below a fourth threshold, wherein the fourth threshold is lower than the first threshold.

9. The method according to any of claims 1 to 8, wherein the transmission resource utilization comprises uplink transmission resource utilization, and wherein the number of active users comprises a number of active uplink users.

10. The method according to claim 9, further comprising: increasing a share of transmission resources of the control channel allocated to control data associated with uplink transmission, in response to determining that the control channel utilization is above the first threshold and that the uplink transmission resource utilization is below the second threshold.

11. The method according to claim 10, further comprising: further increasing the share of transmission resources of the control channel allocated to control data associated with uplink transmission, in response to determining that that downlink transmission resource utilization of the user data channels of the cell is above the second threshold and that a ratio of the downlinktransmission resource utilization and the uplink transmission resource utilization is above a fifth threshold.

12. The method according to claim 11, further comprising: decreasing the share of transmission resources of the control channel allocated to control data associated with uplink transmission, in response to determining that uplink transmission resource utilization of the user data channels of the cell is above the second threshold and that the ratio of the downlink transmission resource utilization and the uplink transmission resource utilization is below a sixth threshold.

13. The method according to any of claims 10 to 12, wherein the share of transmission resources of the control channel allocated to control data associated with uplink transmission is configured to be maintained within a maximum value and a minimum value.

14. The method according to any of claims 1 to 13, wherein the first threshold is in a range of 70-90 %, wherein the second threshold is in a range of 70-90 %, wherein the third threshold is in a range of 5-20, wherein the fourth threshold is within a range of 40-60 %, wherein the fifth threshold is within a range of 1.1-1.3, wherein the sixth threshold is in a range of 0.7-0.9, wherein the minimum value is in a range of 20-40 %, and / or wherein the maximum value is in a range of 60-80 %.

15. The method according to any of claims 1 to 14, wherein the transmission resource utilization comprises a physical resource block utilization, and / or wherein the control channel comprises a physical downlink control channel.

16. An apparatus comprising means for performing the method according to any of claims 1 to 15.

17. A computer program comprising program code configured to, when executed by a processor, cause an apparatus at least to perform the method according to any of claims 1 to 15.

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