TECHNICAL FIELD The present invention pertains to the field of radio communications; and more specifically to the part of this field which is concerned with threshold control in wireless local area networks .

BACKGROUND Recently, the wireless communication technology known as wireless local area network (WLAN) has been the subject of increased interest from cellular network operators. WLAN is often also referred to as Wi-Fi (Wireless Fidelity) , which is, strictly speaking, a trade name for WLAN solutions used by the so-called Wi-Fi alliance. For convenience, the terms WLAN and Wi-Fi will be used interchangeably herein. The interest is partly about using the WLAN technology as an extension, or alternative to cellular radio access network technologies to handle the ever increasing wireless bandwidth demands. Cellular operators that are currently serving mobile users with, for example, any of the 3GPP (third generation partnership project) technologies, such as LTE, UMTS / WCDMA or GSM, see WLAN as a wireless technology that can provide good support in their regular cellular networks. The term "operator-controlled Wi-Fi" points to a WLAN deployment that on some level is integrated with a cellular network operator's existing network and where the 3GPP radio access networks and the WLAN wireless access may even be connected to the same core network and provide the same services.

WLAN is standardized in the IEEE 802.11 Working Group (WG) specifications.

WLAN is a technology that currently mainly operates on the 2.4 GHz or the 5 GHz bands. In WLAN, radio nodes referred to as access points (APs) provide wireless communication services to wireless communication devices usually referred to as stations (STAs) in the WLAN standard. The IEEE 802.11 specifications regulate the APs and the STAs physical layer, media access control (MAC) layer and other aspects to secure compatibility and inter-operability between APs and STAs. WLAN is generally operated in unlicensed bands, and as such, communication using WLAN may be subject to interference sources from any number of both known and unknown devices. WLAN is frequently also used as wireless extensions to fixed broadband access, for example, in domestic environments and hotspots, like airports, train stations, restaurants etc.

Currently, when a STA comes within communication range (coverage) of an AP, the STA might try to connect (associate) to that AP. Communication range is here defined as the minimum received signal strength that could support a reliable communication between the STA and the AP. This is known as "Wi-Fi-if-coverage" network selection. However, in certain situations, it has been seen as beneficial for the STA to not connect the instant it comes under coverage, but rather when its received signal strength reaches a desirably high value (usually associated with a certain quality level) . This may, for example, be applicable to situations, when a STA has an alternative connection via another access network (e.g. a cellular network such as a 3GPP network) and it would only connect to the WLAN if the WLAN connection is of a better quality than the cellular one. Alternatively, the AP may instead monitor its received signal strength, associated with a transmission from the STA, and based thereon decide if the STA can be associated to the AP. Such mechanisms are proposed, for example, in WO 2014/011094 Al . The minimum received signal strength that the STA (AP) must observe in order for the STA to be able to associate with the AP is herein referred to as the admission threshold (ADMT) . The ADMT can be dynamically adjusted in order to reflect radio conditions, network conditions, etc. However, from the above, it should be clear that the ADMT is usually set higher than the Wi-Fi-if-coverage threshold.

WLAN is a contention based technology using a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) . This demands that a device (AP or STA) that wishes to send data first senses whether or not a common (shared) communication channel is in use before performing a transmission on the channel. This is done in order to avoid multiple simultaneous transmissions by several devices on the channel - which would usually result in a loss of data and a need of retransmissions. This procedure, where it is checked if the channel is clear (not busy/occupied) for use, is usually referred to as a Clear Channel Assessment (CCA) . In order for a device to deem the channel busy, it has to detect a transmission, the received signal strength of which exceeds a threshold, herein referred to as the Clear Channel Assessment Threshold (CCAT) .

The "Wi-Fi-if-coverage" threshold and the CCAT are usually not set to have any predetermined relationship, meaning that the AP might "listen" to a STA, which is not within "Wi-Fi-if-coverage", when performing the CCA; and if this STA happens to be transmitting, the AP will then need to back off and wait for a certain amount of time before transmitting. This clearly reduces the efficiency of the communication system.

Some attempts have, however, been made to set the CCAT in a more efficient manner.

US 2006 0046739 Al proposes a coupling between the CCAT and a communication sensitivity threshold that controls a cell size associated with an AP. This method seems to improve intra-cell and inter-cell network efficiency by adjusting detection and communication sensitivities according to an AP cell coverage area, and may realize available network capacity gain. However, if a cell size is incorrectly determined this may result in low system efficiency. If the cell size is underestimated, a "hidden node" problem may occur, causing collisions within the cell. If the cell size is overestimated, there may be an unnecessarily high sensitivity within the cell.

JP 04406650 B2 proposes that the CCAT is adjusted based on a trigger condition, for example, that a packet error rate exceeds a target maximum limit. A sensing range is adaptive to the reception quality which is affected by an amount of interference in an area. This is a reactive approach, working upon the trigger, which means that performance degradation has happened before the adjustment. Furthermore, the packet error rate is not a direct measure of user experience. In practice, link adaptation (LA) algorithms usually use packet error rate as an input to adjust modulation and coding schemes (MCS) . Therefore, the LA and the CCAT adjustment may interfere with each other in an undesired manner.

Consequently, a main problem addressed herein is to provide ways and means for improved control of the CCAT.

SUMMARY

According to one aspect, the above-stated problem may be solved with a method in a device for controlling a CCAT usable by an AP of a WLAN. The method comprises obtaining an ADMT associated with the AP. The method further comprises determining the CCAT based on the ADMT.

In exemplary embodiments, the method may further comprise the obtaining of a margin value MAR, which is used in the determining of the CCAT to establish an amount of deviation of the CCAT from the ADMT.

In exemplary embodiments, the MAR may be a fixed value. However, in other exemplary embodiments, the method may comprise updating the MAR and determining the CCAT anew based on the updated MAR and the ADMT. According to a second aspect, the above-stated problem may be solved with a device for controlling a CCAT usable by an AP of a WLAN. The device comprises processing circuitry, which is configured to obtain an ADMT associated with the AP and to determine the CCAT based on the ADMT.

In exemplary embodiments, the processing circuitry of the device may be further configured to obtain a margin value MAR and to determine the CCAT also based on the MAR such that the MAR establishes deviation of the CCAT from the ADMT.

In exemplary embodiments, the MAR obtained by the processing circuitry may be a fixed value. However, in other exemplary embodiments, the processing circuitry may be configured to update the MAR and to determine the CCAT anew based on the ADMT and the updated MAR.

According to other aspects, the above-stated problem may be solved with an AP or an AP controller comprising a device according to the second aspect or exemplary embodiments thereof.

A main advantage, as will explained in more detail below, is that basing the CCAT on the ADMT leads to a more efficient use of communication resources. Another advantage is that the above- indicated aspects do not require any modification of the STAs. Moreover, basing the CCAT on ADMT also avoids many of the above- indicated difficulties with the prior art. A main advantage, associated with embodiments applying the MAR, is that the MAR provides a mechanism for balancing between efficiency and quality.

The inventions will now be described further using exemplary embodiments and referring to the drawings. The persons skilled in the art will appreciate that further aspects, objects and advantages may be associated with particular embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagram illustrating a use of communication thresholds in a WLAN network.

Figure 2 is block diagram illustrating a device for controlling a CCAT according to an exemplary embodiment. Figure 3 is block diagram illustrating an example location of a device for controlling a CCAT.

Figure 4 is a block diagram illustrating an example location of a device for controlling a CCAT.

Figure 5 is a flowchart illustrating a method of controlling a CCAT according to an exemplary embodiment.

Figure 6 is a flowchart illustrating an updating procedure according to an implementation example.

Figure 7 is a flowchart illustrating an updating procedure according to an implementation example. Figure 8 is a table providing non-limiting examples of performance indicators.

Figure 9 is a block diagram illustrating a non-limiting implementation design of processing circuitry.

Figure 10 is a block diagram illustrating a non-limiting implementation example of processing circuitry.

DETAILED DESCRIPTION

Figure 1 is a diagram illustrating an AP la and a use of various thresholds according legacy procedures as well as according to proposed exemplary embodiments. The AP la is part of a WLAN 3 and is configured to provide wireless communication services to (wireless) stations which may be in the vicinity of the AP la. Figure 1 depicts, by way of example, three STAs 2a, 2b and 2c. The term "station", or abbreviated "STA", is used in the WLAN standard and will here be used generally for denoting any wireless communication device which is capable of wireless communications comprising WLAN communications. The term STA consequently comprises, by way of example, any device which may be used by a user for wireless communications. The term STA may in particular comprise a mobile terminal, a fixed terminal, a user terminal (UT) , a wireless terminal, a wireless transmit/receive unit (WTRU) , a mobile phone, a cell phone, a table computer, a smart phone, etc. Yet further, the term STA may comprise MTC (Machine Type Communication) devices, which do not necessarily involve human interaction. MTC devices are sometimes referred to as Machine-to-Machine (M2M) devices.

The terms wireless communication device and station (STA) will be used interchangeably herein.

A contour CI is shown in figure 1, and CI corresponds to a legacy set CCAT . That is, the contour CI may be interpreted such that a received signal strength experienced by the AP la, from transmissions from any STA which is on or within the contour CI, is above the legacy CCAT. A legacy set CCAT is typically less than or equal to -72 dBm for 20 MHz channel widths, -75 dBm for 10 MHz channel widths and -78 dBm for 5 MHz channel widths. Since the legacy set CCAT is usually relatively small, the contour CI is correspondingly relatively far away from the AP la and may even, as mentioned, extend beyond a Wi-Fi-if-coverage range. Figure 1 also shows a contour C2, which corresponds to an ADMT . That is, STAs on or within the contour C2 will experience received signal strengths, from transmissions from the AP la, that exceed the ADMT. In figure 1, the STAs 2a and 2b are within the contour C2 and they are therefore allowed to connect to the AP la. The STA 2c is, however, exterior to the contour C2 and may therefore not connect to the AP la. The STA 2c is however interior to the contour CI and is therefore still taken into account for purposes of legacy CCA despite the fact that it is a fairly long way from the AP la and will not connect to the AP la, at least not until it has moved much closer to the AP la. Exemplary embodiments are therefore mainly directed to controlling the CCAT in ways which make more efficient use of communication resources.

Figure 2 is a block diagram illustrating a device 5 for controlling the CCAT in accordance with an exemplary embodiment. For convenience, the device 5 is here referred to as a CCAT controller. The CCAT controller 5 is connected to the AP la and comprises processing circuitry 7, which is configured to control a CCAT used by (at least) the AP la. The processing circuitry 7 is configured to obtain an ADMT associated with the AP la. The ADMT may, for example, be delivered to the CCAT controller 5 from the AP la or from some other node, such as an AP controller. Alternatively, the CCAT controller 5 may be responsible for determining the ADMT and to inform the AP la about the applicable ADMT. It is here proposed that the processing circuitry 7 is configured to determine the CCAT based on the ADMT, which will be described in greater detail below. Upon determining the CCAT, the processing circuitry 7 may be configured to send the determined CCAT to the AP la, which is then responsible for implementing the CCAT when performing CCA.

As further illustrated in figure 2, the AP la may have one or more neighbour APs lb, and transmissions from the AP la and/or STAs associated with the AP la may cause interference 9 toward the neighbour AP(s) lb and any STAs associated therewith. In exemplary embodiments, the processing circuitry 7 may obtain information 11 relating to such neighbour AP interference 9 and may be configured to account for such information when controlling the CCAT, as will be described in greater detail below. The information 11 may be provided by neighbour AP(s) lb directly or, as illustrated in figure 2, via an intermediate device 13, which may be a node of the WLAN 3, such as, for example, an AP controller. In figure 2, the CCAT controller 5 is depicted as a stand-alone device which is connected to the AP la. However, the CCAT controller may also be comprised as a part of some other device of the WLAN 3. For example, as illustrated in figure 3, the CCAT controller 5 may be comprised in the AP la, or as illustrated in figure 4, in an AP controller 15.

Figure 5 is a flowchart that illustrates a method which may be applied for controlling the CCAT of the AP la according to an exemplary embodiment. The method of figure 5 may for example be executed by the processing circuitry 7 of the CCAT controller 5.

At an action 21, the ADMT associated with the AP la is obtained. The currently used ADMT may be provided by the AP la or be provided by some other node of the WLAN 3. The action 21 may in exemplary embodiments entail the actual determination of the ADMT, in which case the AP la will also be informed of the determined ADMT.

The method continues with an action 23 (optional) of obtaining a margin value MAR, the use of which will soon be explained. In some embodiments, the obtained MAR may be a fixed value, indicated as an optional action 23a. That is, the MAR is in this case never changed. However, in other embodiments, the MAR may subsequently be updated. Irrespective of whether the MAR is fixed or not, the obtaining of the MAR in action 21 may be performed in various ways. The MAR may be a predetermined value which is obtained from storage (not shown) in, for example, an electronic data memory, a database or from some centrally located node of the WLAN 3. The MAR may alternatively be based on input data, which may be real time or historical data. Such input data may comprise data relating to transmission efficiency of the AP la, data relating to signal quality relating to STAs associated with the AP la, data relating to the neighbour AP interference 9 etc.

The method continues with an action 25 of determining the CCAT based on the ADMT. The CCAT may, for example, be determined as a predetermined function of the ADMT. A simple example could be to set CCAT equal to the ADMT or to an affine transformation of the ADMT.

However, in exemplary embodiments, it is suggested to base the determination of the CCAT also on the MAR, indicated as an optional action 25a in figure 5. A purpose of the MAR is then to establish an amount of deviation - a margin - of the CCAT from the ADMT. As an example, CCAT could for example be determined as CCAT = f (ADMT, MAR), where f is a function such that f (ADMT, 0 ) = AMDT and f (ADMT, MAR) ≠ ADMT, provided MAR ≠ 0 of course. Preferably, the function f is such that the larger the absolute value of MAR, the more the CCAT will deviate from the ADMT. A very simple example could be to set CCAT = ADMT - MAR.

An advantage of using the MAR is that it provides a mechanism for a balancing between transmission opportunities on the one hand and transmission quality on the other hand.

In exemplary embodiments, the action 25 may be subject to a restriction involving bounds on the CCAT, indicated as an optional action 25b in figure 5. That means that there is a set lower bound CCAT_min, which the CCAT may not fall below, and a set upper bound CCAT_max, which the CCAT may not rise above. In this case the CCAT may, for example, be determined as

CCAT = max (min (ADMT, CCAT_max) , CCAT_min) ,

CCAT = max (min ( f (ADMT, MAR) , CCAT_max) , CCAT_min) , or CCAT = max (min (ADMT-MAR, CCAT_max) , CCAT_min) .

The lower bound CCAT_min may, for example, be determined based on a given receiver sensitivity. In exemplary embodiments, the lower bound CCAT_min could be mandated by "high-level" system settings, for example, from an AP controller, in order to limit an independence of the individual APs . It is envisioned that spectrum legislations or regulations could demand or suggest a value for the upper bound CCAT_max.

The method continues with an action 27 (optional) of updating the MAR. The updating of the MAR may be performed periodically and/or in response to one or more predefined trigger events. After (each) update of the MAR the method returns to actions 25 and 25a, wherein the CCAT is determined anew, now of course based on the updated MAR.

Figure 6 is a flowchart 27a that illustrates as a non-limiting implementation example one way of performing the MAR update 27.

The flowchart 27a begins with an action 27al of obtaining a measure of a communication quality of communications between the AP la and one or more STAs associated with the AP la. The measure of a communication quality may relate to uplink communications, downlink communications or combinations thereof.

The flowchart 27a continues with an action 27a2 of comparing the measure of a communication quality with a communication quality target (target for short) .

The flowchart 27a continues with an action 27a3 of updating the MAR based on the comparing in action 27a2.

In exemplary embodiments, the action 27a2 may entail determining whether the measure of a communication quality is below or above the target. If the measure of a communication quality is below the target, the action 27a3 may entail increasing the MAR, for example, by a predetermined step MAR_step. In exemplary embodiments, the increased MAR may be obtained as min (MAR+MAR_step,MAR_max) , where MAR_max is a set upper bound for the MAR. If, instead, the measure of a communication quality is above the target, the action 27a3 may entail decreasing the MAR, for example, by the predetermined step MAR_step. In exemplary embodiments, the decreased MAR may be obtained as min (MAR- MAR_step,MAR_min) , where MAR_min is a set lower bound for the MAR. In the unlikely event that the measure of a communication quality should equate the target, various actions can be contemplated, for example, the MAR may be increased, decreased or left unchanged. Naturally, if the MAR is unchanged, there is no need to perform the actions 25 anew.

In exemplary embodiments, the target may be a configurable target, which may be configured, for example, by an operator or based on selected input data.

In exemplar embodiments, the measure of a communication quality may be based on one or more performance indicators. A performance indicator is here a value or a collection of values that provide an indication of the performance, e.g. in terms of success, efficiency, quality or amount, of communications between the AP la and one or more STAs associated with the AP la. Figure 8 is table with a non-limiting list of performance indicators 31 which may be used to obtain the measure of a communication quality. The list comprises Modulation and Coding Scheme (MCS) 31a used by the AP la, a retransmission rate 31b associated with the AP la, number of retransmissions from the AP la due to collisions 31c, data throughput 31d and latency 31e.

Figure 7 is a flowchart 27b that illustrates one non-limiting way of performing the MAR update 27. The procedures indicated in figures 6 and 7 are however not mutually exclusive.

The flowchart 27b begins with an action 27bl of obtaining information 11 relating to neighbor AP (NAP) interference 9. NAP interference 9 is here interference toward one or more NAPs lb of the AP la which is caused or contributed to by transmissions from the AP la and/or one or more STAs connected to the AP la.

The flowchart 27b continues with and action 27b2 of updating the MAR based on the information 11 relating NAP interference 9. In exemplary embodiments, the information 11 relating to NAP interference 9 may simply be a message indicating that one or more NAPs lb experience an undesirable level of interference. The action 27b2 may then entail increasing the MAR, for example, by predetermined step MAR_step.

With reference again to figure 1, it is now assumed that a CCAT has been determined based on ADMT in accordance with embodiments disclosed or indicated above. A contour C3 corresponds to this CCAT in the sense that the received signal strength at the AP la from transmissions from STAs on or within the contour C3 is above the CCAT. Since the CCAT is based on the ADMT, the contour C3 is clearly within the contour CI corresponding to the legacy set CCAT, which is much lower than the ADMT. There is also used a positive MAR in this example, so that the contour C2 is within the contour C3 by distance D, which depends on the value of the MAR. The STA 2c is within the contour CI but on the outside of the contour C2. With the legacy set CCAT, the STA 2c would be taken into account for CCA, although it is too far away from the AP la to be allowed to connect to the AP la. That is, in case the STA 2c is transmitting, the AP la will have to back off and wait, which reduces an efficiency of the communications. However, with the CCAT corresponding to the contour C3, transmissions from the STA 2c will not be taken into account in the CCA, so that the channel will be viewed as free. Hence by linking the CCAT to the ADMT, the AP la will only, for the purpose of CCA, consider STAs which are likely candidates to contend for communication resources and/or which can more significantly contribute to interference levels.

Above, it has been tacitly assumed that the MAR is a value that is greater than or equal to zero, such that an "uptake area" (the area within the contour C2) within which STAs may connect to the AP la is contained within a "blocking area" (the area within the contour C3) within which STAs will be taken into account for purposes of CCA. Naturally, it is possible to make an opposite sign convention for the MAR, that is, the MAR is assumed to be a value smaller than or equal to zero. If so, the above-described procedures should of course be modified mutatis mutandis, if the relationship between "uptake area" and the "blocking area" is to remain.

The processing circuitry 7 of the CCAT controller 5 may be configured to perform CCAT control in accordance with any one the methods disclosed or indicated above. The persons skilled in the art will appreciate that the processing circuitry 7 may be implemented with conventional electronic circuit technologies, which exist in profusion. The processing circuitry 7 may, for example, be implemented using circuitry with individual hardware components, application specific integrated circuitry, programmable circuitry or any combination thereof. The processing circuitry 7 may also fully or partially be implemented using one or more digital processors and computer readable memory with program code which may be executed by the one or more digital processors to perform one or more functions performed by the processing circuitry 7. Consequently, in an embodiment, the processing circuitry 7 is configured to obtain the ADMT, which is associated with the AP la. Moreover, the processing circuitry 7 is configured to determine the CCAT based on the ADMT.

In exemplary embodiments, the processing circuitry 7 may be further configured to obtain the MAR and to determine the CCAT also based on the MAR such that the MAR establishes an amount of deviation of the CCAT from the ADMT. In exemplary embodiments, the MAR may be a fixed value.

In exemplary embodiments, the processing circuitry 7 may be configured to determine the CCAT such that the CCAT is restricted by bounds. That is, the CCAT is restricted to values between a lower bound CCAT_min and an upper bound CCAT_max. In exemplary embodiments, the processing circuitry 7 may be configured to update the MAR and to determine the CCAT anew based on the ADMT and the updated MAR.

In exemplary embodiments, the processing circuitry 7 may be further configured to obtain a measure of a communication quality of communications between the AP la and one or more STAs connected to the AP la. The processing circuitry 7 may be further configured to compare the obtained measure of a communication quality with a communication quality target and to update the MAR based on the comparison.

In exemplary embodiments, the processing circuitry 7 may be configured to obtain the measure of a communication quality based on one or more performance indicators. In exemplary embodiments, the one or more performance indicators may comprise at least one of the performance indicators 31 listed in figure 8.

In exemplary embodiments, the processing circuitry 7 may be configured to obtain information 11 relating to neighbour AP interference 9 generated by the AP la and/or one or more STAs serviced by the AP la and to update of the MAR in dependence of the information 11 relating to neighbour AP interference 9.

Figure 9 is a block diagram 7a illustrating one non-limiting implementation design for the processing circuitry 7 of the CCAT controller 5.

The block diagram 7a comprises obtaining circuitry 41, which is configured for obtaining data, for example, one or more parameters to be used in CCAT control. Here the obtaining circuitry 41 comprises circuitry 41a configured to obtain the ADMT of the AP la, e.g. in ways described or indicated earlier.

Optionally, the obtaining circuitry 41 may comprise circuitry 41b configured to obtain the MAR, e.g. in ways described or indicated earlier . Optionally, the obtaining circuitry 41 may comprise circuitry 41c configured to obtain a measure of a communication quality of communications between the AP la and one or more STAs connected to the AP la, e.g. in ways described or indicated earlier. Optionally, the obtaining circuitry 41 may comprise circuitry 41d configured to obtain information 11 relating to neighbour AP interference 9, e.g. in ways described or indicated earlier.

The processing circuitry of the block diagram 7a further comprises CCAT determining circuitry 43. The CCAT determining circuitry 43 comprises circuitry 43a configured to determine the CCAT based on the ADMT obtained by circuitry 41a, e.g. in ways described or indicated earlier.

Optionally, the CCAT determining circuitry 43 may comprise circuitry 43b configured such that the determination of the CCAT is based also on the MAR obtained by circuitry 41b, e.g. in ways described or indicated earlier.

Optionally, the CCAT determining circuitry 43 may comprise circuitry 43c configured such that the determination of the CCAT is restricted by bounds (CCAT_min and CCAT_max) , e.g. in ways described or indicated earlier.

Optionally, the processing circuitry of the block diagram 7a may comprise MAR updating circuitry 45 configured to update the MAR. The updating circuitry 45 may be configured to provide the updated MAR to the CCAT determining circuitry 43 which may be configured to determine the CCAT anew based on the ADMT and the updated MAR.

Optionally, the MAR updating circuitry 45 may comprise circuitry 45a configured to update the MAR based on the measure of a communication quality obtained by circuitry 41c, e.g. in ways described or indicated earlier. Optionally, the MAR updating circuitry 45 may comprise circuitry 45b configured to update the MAR based on the information 11 relating to neighbour AP interference 9 obtained by circuitry 41d, e.g. in ways described or indicated earlier. In exemplary embodiments, the blocks of the block diagram 7a may be implemented as separate but operationally connected units.

Figure 10 is a block diagram 7b illustrating another non-limiting implementation design for the processing circuitry 7 of the CCAT controller 5. The processing circuitry of block diagram 7b comprises one or more digital processors 49 for carrying out functions relating to the CCAT control using computer executable program code (code for short) instructions stored on a computer readable memory (memory for short) 50. In exemplary embodiments, the digital processor (s) 49 may, for example, comprise microprocessor ( s ) , digital signal processor ( s ) , micro controller ( s ) , or combinations thereof.

In the example of figure 10 there is also provided an input/output (I/O) interface 47, via which the digital processor (s) may receive or transmit data. In general, this is, however, optional. In particular, if the CCAT controller 5 is comprised in another device, it may be that the digital processor (s) 49 instead receive and transmit data via some internal system of the device, such as, for example, an internal data bus or similar. The memory 50 comprises obtaining code 51, with instructions for obtaining data, for example, one or more parameters to be used in CCAT control. Here the obtaining code 41 comprises code 41a with instructions to obtain the ADMT of the AP la, e.g. in ways described or indicated earlier. Optionally, the obtaining code 51 may comprise code 51b with instructions to obtain the MAR, e.g. in ways described or indicated earlier. Optionally, the obtaining code 51 may comprise code 51c with instructions to obtain a measure of a communication quality of communications between the AP la and one or more STAs connected to the AP la, e.g. in ways described or indicated earlier. Optionally, the obtaining code 51 may comprise code 51d with instructions to obtain information 11 relating to neighbour AP interference 9, e.g. in ways described or indicated earlier.

The memory 50 further comprises CCAT determining code 53. The CCAT determining code 53 comprises code 53a with instructions to determine the CCAT based on the ADMT obtained by the code 51a, e.g. in ways described or indicated earlier.

Optionally, the CCAT determining code 53 may comprise code 53b with instructions such that the determination of the CCAT is based also on the MAR obtained by the code 51b, e.g. in ways described or indicated earlier.

Optionally, the CCAT determining code 53 may comprise code 53c with instructions such that the determination of the CCAT is restricted by bounds (CCAT_min and CCAT_max) , e.g. in ways described or indicated earlier. Optionally, the memory 50 may comprise MAR updating code 55 with instructions to update the MAR. The updating code 55 may contain instructions to provide the updated MAR as input to the CCAT determining code 53 which may in turn comprise instructions to determine the CCAT anew based on the ADMT and the updated MAR. Optionally, the MAR updating code 55 may comprise code 55a with instructions to update the MAR based on the measure of a communication quality obtained by the code 41c, e.g. in ways described or indicated earlier.

Optionally, the MAR updating code 55 may comprise code 55b with instructions to update the MAR based on the information 11 relating to neighbour AP interference 9 obtained by the code 51d, e.g. in ways described or indicated earlier.

Above, the invention has been described with various embodiments. These embodiments are only to be viewed as non-limiting examples, and the scope of protections is instead defined by the appending claims. In particular, a technical feature should not be viewed as essential only because it has been mentioned in connection with an exemplary embodiment.