Communication device and communication method

Abstract

The present disclosure relates to a communication device and a communication method. This communication device controls at least one AP that uses a plurality of wireless devices, and is configured to execute: a first process of setting one or more parameters including a channel that can be allocated to an AP; a second process of calculating a utility function for each of the parameters; a third process of selecting an optimal parameter on the basis of the result of the calculation; and a process of repeating the first process, the second process, and the third process for each of the at least one AP. The first process is performed so as to increase the probability that parameters currently in use are maintained for at least one of the plurality of wireless devices.

Description

Communication device and communication method

[0001] The present disclosure relates to a communication device and a communication method.

[0002] There is a technique for optimizing the throughput of the entire system by optimizing parameters such as the frequency channel and bandwidth to be used for a plurality of base stations (APs) possessed by the system.

[0003] The optimization of parameters can be realized, for example, by defining an evaluation value based on the frequency channel and bandwidth used by each AP and selecting a parameter that can maximize the minimum value or the sum of the evaluation values. As an example of this method, RATOP (Resource allocation based on Area Throughput Optimization Policy) is known (see, for example, Non-Patent Document 1).

[0004] In RATOP, the centralized control device grasps the state of mutual interference of each AP and allocates radio resources such as the frequency channel and bandwidth to be used by each AP. Also in RATOP, as an evaluation value, a utility function that is the satisfaction degree of the expected throughput with respect to the required traffic volume is defined.

[0005] The centralized control device performs control, for example, so as to maximize the total value of the utility function. When the system has a configuration in which APs perform wireless communication using devices in a plurality of frequency bands, the centralized control device optimizes the throughput for each frequency. The plurality of frequency bands are, for example, the 5 GHz band and the 6 GHz band. Note that all of the plurality of frequency band devices possessed by the AP may be devices corresponding to the same frequency band.

[0006] BAHirantha Sithira Abeysekera et al., "Network Controlled Frequency Channel and Bandwidth Allocation Scheme for IEEE 802.11a / n / ac Wireless LANs: RATOP", 2014 IEEE 25th International Symposium on Personal, Indoor and Mobile Radio Communications, pp.1041-1045

[0007] In centralized wireless resource control systems like RATOP, parameter updates for access points (APs) within the system are expected. These parameter updates can be performed either per frequency band or per AP. However, in either case, the parameter update process causes temporary communication interruptions that occur simultaneously for many wireless devices connected to each AP. This leads to a problem of unstable communication quality across the entire system.

[0008] This disclosure aims to provide a communication device and a communication method that can stabilize the overall communication quality of the system by reducing the frequency of communication interruptions when parameter updates are performed for each frequency band and for each AP, in order to solve the above-mentioned problems.

[0009] A first aspect of this disclosure is a communication device for controlling an AP using at least one or more wireless devices, configured to perform a first process of setting one or more parameters including channels that can be assigned to the AP; a second process of calculating a utility function for each of the parameters; a third process of selecting the optimal parameters based on the calculation results; and a process of repeating the first, second, and third processes so that each of the at least one AP is targeted, wherein the first process is preferably performed in such a way that the probability of maintaining the parameters currently in use for at least one of the wireless devices is increased.

[0010] Furthermore, a second aspect of this disclosure is a method to be implemented by a communication device that controls an AP using multiple wireless devices, comprising: setting one or more parameters including channels that can be assigned to the AP; calculating a utility function for each of the parameters; selecting the optimal parameter based on the calculation results; and repeating the setting, calculation, and selection process so that each of the at least one AP is targeted, wherein the setting is preferably performed in such a way that the probability of maintaining the parameters currently in use for at least one of the multiple wireless devices is high.

[0011] According to the embodiments of this disclosure, when parameter updates are performed for each frequency band and for each AP, the communication quality of the entire system can be stabilized by reducing the frequency of communication interruptions.

[0012] This figure shows an example configuration of a wireless communication system according to Embodiment 1 of the present disclosure. This figure shows the hardware configuration of a centralized control device according to Embodiment 1 of the present disclosure. This figure shows parameter updates according to Embodiment 1 of the present disclosure. This flowchart shows the processing performed by the centralized control device according to Embodiment 1 of the present disclosure. This figure shows the RATOP algorithm executed by the centralized control device according to Embodiment 1 of the present disclosure. This figure shows parameter updates according to a comparative example. This figure shows the options for allocating wireless resources according to Embodiment 2 of the present disclosure. This figure shows the allocation of wireless resources according to Embodiment 3 of the present disclosure.

[0013] Embodiments of this disclosure will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repetition of the description may be omitted.

[0014] Embodiment 1 Figure 1 is a diagram showing an example configuration of a wireless communication system according to Embodiment 1 of the present disclosure. The wireless communication system 100 includes a central control device 10. The central control device 10 grasps the state of mutual interference of each wireless device and allocates wireless resources such as frequency channels and bandwidth to be used by each wireless device. This allocation is performed in a manner that maximizes the overall throughput of the wireless communication system 100.

[0015] The wireless communication system 100 also includes an AP20a. The AP20a is a wireless device connected to the network 8. In this embodiment, the AP20a is connected to the central control unit 10 via the network 8.

[0016] AP20a includes wireless devices 22a and 22b. Wireless devices 22a and 22b each enable wireless communication using a specific frequency band. In other words, AP20a performs wireless communication using wireless resources in multiple frequency bands.

[0017] For example, wireless device 22a enables wireless communication using the 5 GHz frequency band. Also, for example, wireless device 22b enables wireless communication using the 6 GHz frequency band.

[0018] Here, AP20a is shown as performing wireless communication using wireless resources in multiple frequency bands by multiple wireless devices, but it is not limited to this. In other words, AP20a can be any form that performs wireless communication using wireless resources in at least one frequency band by multiple wireless devices, and may be, for example, an MLD (Multi-Link Device). Furthermore, this also applies to other APs related to this disclosure, which will be described later.

[0019] AP20a has a terminal 40 under its control. Terminal 40 has wireless devices 22a and 22b. AP20a and terminal 40 perform wireless communication using the 5GHz frequency band with the wireless device 22a that both have. Similarly, AP20a and terminal 40 perform wireless communication using the 6GHz frequency band with the wireless device 22b that both have.

[0020] The wireless communication system 100 includes an AP20b. The AP20b is a wireless device connected to the network 8. In this embodiment, the AP20b is connected to the central control unit 10 via the network 8. The AP20b also has wireless devices 22a and 22b.

[0021] The wireless communication system 100 also includes an AP20c, which is a wireless device connected to the network 8. In this embodiment, the AP20c is connected to the central control unit 10 via the network 8. The AP20c also has wireless devices 22a and 22b.

[0022] Hereafter, APs and terminals will sometimes be collectively referred to as wireless devices.

[0023] Here, dashed arrows indicate wireless devices that interfere with each other. That is, dashed arrows indicate wireless devices that allocate wireless resources to each other. In this disclosure, the central control unit 10 allocates the wireless resources that each AP should use, for example, based on RSSI (Received Signal Strength Indicator). More specifically, the central control unit 10 allocates wireless resources by determining the 5GHz band wireless resources that each AP will use and the 6GHz band wireless resources that each AP will use.

[0024] Figure 2 shows the hardware configuration of a centralized control device according to Embodiment 1 of the present disclosure. Each function of the centralized control device 10 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array), or it may be configured as a program executed by a processor such as a CPU.

[0025] For example, the centralized control device 10 can be implemented using a computer and a program, and the program can be recorded on a storage medium or provided via a network.

[0026] As shown in Figure 2, the centralized control unit 10 has an input unit 108, an output unit 101, a communication unit 102, a CPU 103, a memory 104, and an HDD 105 connected via a bus 106, and functions as a computer. The centralized control unit 10 is also capable of inputting and outputting data to and from a computer-readable storage medium 107.

[0027] The input unit 108 is, for example, a keyboard and mouse. The output unit 101 is, for example, a display device such as a display.

[0028] The communication unit 102 is, for example, a communication interface that communicates with a wireless device to be controlled.

[0029] The CPU 103 controls each component of the central control unit 10 and performs predetermined processing. The memory 104 and HDD 105 store data, etc.

[0030] The storage medium 107 is capable of storing programs and the like that cause the central control unit 10 to execute its functions. Note that the architecture of the central control unit 10 is not limited to the example shown in Figure 2.

[0031] Figure 3 is a diagram illustrating the parameter update according to Embodiment 1 of the present disclosure. The upper part of Figure 3 shows the parameter update using AP20a as an example when the parameter update is performed for each frequency band. The lower part of Figure 3 shows the parameter update using AP20a as an example when the parameter update is performed for each AP. Hereafter, the diagrams showing the parameter update according to the present disclosure will be indicated as (1) for the former case and (2) for the latter case.

[0032] In Figure 3, the horizontal axis represents time. Furthermore, Figure 3 shows AP20a, wireless device 22a, and wireless device 22b as wireless devices that perform parameter updates. When these wireless devices are shown with solid lines, it indicates that a parameter update has been decided. On the other hand, when these wireless devices are shown with dashed lines, it indicates that a parameter update will not be performed.

[0033] In this embodiment, the centralized control device 10 sequentially performs the necessary number of parameter updates in both cases (1) and (2). The contents described above for Figure 3 are the same for subsequent figures showing parameter updates related to this disclosure.

[0034] In this embodiment, the centralized control device 10 determines wireless resources separately for each of the multiple frequency bands. In this embodiment, an example is shown in which the centralized control device 10 determines wireless resources for the 5 GHz band and then determines wireless resources for the 6 GHz band.

[0035] In this case, if the central control unit 10 decides to update parameters for a specific frequency band, it will prioritize selecting the currently used parameters for at least one of the other frequency bands used by the AP using that frequency band. On the other hand, APs that do not update parameters in the 5GHz band can change the parameters in the 6GHz band without restriction.

[0036] Prioritizing the selection of currently used parameters can be achieved, for example, by excluding currently used parameters from parameter updates or by assigning them a lower priority for parameter updates.

[0037] For example, in case (1), let's assume that the parameter update for the 5GHz band is decided first. AP20a uses the 6GHz band in addition to the 5GHz band. Therefore, the central control unit 10 prioritizes selecting the parameters currently in use for the 6GHz band. More specifically, the central control unit 10 either excludes the 6GHz band from parameter updates or gives it a lower priority for parameter updates.

[0038] In case (2), let's assume that the parameter update for AP20a has been decided first. AP20a uses frequencies in the 6GHz band in addition to the 5GHz band. Therefore, the central control unit 10 prioritizes selecting the parameters currently in use for the 6GHz band. More specifically, the central control unit 10 either excludes the 6GHz band from parameter updates or gives it a lower priority.

[0039] As described above, by performing parameter updates, the number of parameter updates can be reduced in both cases (1) and (2). In other words, whether parameter updates are performed per frequency band or per AP, the overall communication quality of the system can be stabilized by reducing the frequency of communication interruptions.

[0040] Figure 4 is a flowchart showing the processing performed by the centralized control device according to Embodiment 1 of the present disclosure. First, in step 100, the centralized control device 10 determines whether it is an information collection trigger. If it is an information collection trigger, the process proceeds to step 102. If it is not an information collection trigger, the process proceeds to step 104.

[0041] In step 102, the centralized control device 10 performs information collection.

[0042] Next, in step 104, the centralized control device 10 determines whether it is a calculation trigger. If it is a calculation trigger, the process proceeds to step 106. If it is not a calculation trigger, the process returns to step 100.

[0043] In step 106, the centralized control device 10 performs a calculation and proceeds to step 108. Details of the calculation will be described later.

[0044] Next, in step 108, the centralized control device 10 determines whether it is a parameter setting trigger. If it is a parameter setting trigger, the process proceeds to step 110. If it is not a parameter setting trigger, step 108 is repeated.

[0045] In step 110, the centralized control device 10 performs parameter setting.

[0046] Figure 5 is a diagram showing the RATOP algorithm executed by the centralized control device according to Embodiment 1 of the present disclosure. This algorithm corresponds to the details of the calculation performed by the centralized control device 10 in step 108 of the flowchart shown in FIG. 4.

[0047] Prior to the description of the RATOP algorithm, the utility function will be described. The wireless communication system 100 according to the present embodiment has a plurality of APs connected to the network 8. The centralized control device 10 performs RATOP control on the plurality of APs. At this time, it is assumed that the evaluation value used as the control index is the utility function U (corresponding to the satisfaction degree) shown in Equation 1.

[0048] a: Identifier of APb: Bandwidthc: Channel (primary channel)R: Data rate (MCS)

[0049] Hereafter, APs with identifier 'a' will be collectively referred to as AP(a). The transmittable traffic amount of AP(a) is AP(a)'s expected throughput, which depends on the channel usage status of other APs, etc. The expected throughput of each AP is derived from the positional relationship between APs using the same frequency channel. This positional relationship is estimated using RSSI, for example. For example, if APs in interfering positions use the same frequency channel, it can be estimated that the throughput will decrease.

[0050] Furthermore, the amount of traffic to be accommodated (which depends on the amount of data generated) is, for example, the estimated maximum traffic of AP(a) shown in Equation 2.

[0051]

[0052] At this time, we assume that the maximum traffic estimate is the traffic capacity per terminal multiplied by the number of assumed terminals. The central control unit 10 then performs a process to maximize the sum ΣU of the utility functions U according to the following algorithm.

[0053] RATOP algorithm: (A) The central control unit 10 "provisionally allocates" the channels and bandwidth used by each AP according to predetermined rules. (B) The central control unit 10 calculates the sum ΣU of the utility functions U of each AP in the case of (A). (C) The central control unit 10 reallocates the channels and bandwidth to APs with low utility functions U and controls them so that ΣU does not decrease. The central control unit 10 then repeats (C) within a predetermined range.

[0054] Referring to Figure 5, the RATOP algorithm will be explained. As shown in Figure 5, the central control unit 10 performs Phase I (initial calculation) and Phase II (optimization) processing.

[0055] First, the central control unit 10 determines the 5GHz band wireless resources. In Phase I, the central control unit 10 selects one AP and designates it as AP-a (S200), selects the bandwidth b that can be allocated to AP-a (S202), selects the channel (primary channel) c that can be allocated to AP-a (S204), and calculates the utility function U of AP-a (S206).

[0056] The central control unit 10 then performs the processes in S204 and S206 for all channels c, and repeats the process for all bandwidths b. In other words, the central control unit 10 calculates the utility function U for each combination of bandwidth b and channel c that can be allocated to the selected AP. In the following embodiments, we will describe combinations of bandwidth and channel, but the processing may be performed on any combination of setting values ​​including channels, not limited to these combinations.

[0057] Next, the central control unit 10 selects a combination of (b, c) based on the utility function U (S208) and repeats the process for all APs. Specifically, if there are multiple choices of combinations of (b, c) that satisfy certain conditions for the utility function U, it checks if there is a combination of (b, c) currently in use among them. If there is a combination of (b, c) currently in use, that combination is given priority.

[0058] The certain condition that the utility function U satisfies is either that it reaches its maximum value, or that the difference between the utility function U at its maximum value and the current utility function U is below a certain threshold.

[0059] Furthermore, if there is an AP that has been continuously used for a time exceeding a certain threshold for a currently used combination of (b, c) whose utility function U satisfies certain conditions, that AP may be excluded from being controlled. This exclusion process can reduce the time and resources required to determine (b, c).

[0060] In Phase II, the central control unit 10 optimizes the utility function U (S210). For example, the central control unit 10 selects the AP with the smallest utility function U, and calculates a utility function for each of the (b, c) combinations that can be assigned to the selected AP, provided that the degradation of the sum ΣU of the utility functions U is within a certain range. Note that the certain range may include cases where the degradation is negative, i.e., an improvement. Then, based on the calculated utility functions, it selects a combination of (b, c) and repeats the process for all APs.

[0061] The central control unit 10 then determines the bandwidth and channel after allocation for each AP's selected combination of (b, c) (S212).

[0062] Next, the central control unit 10 determines the 6GHz band wireless resources. That is, the central control unit 10 performs Phase I and Phase II processing again for the 6GHz band wireless resources.

[0063] However, in steps 202 and 204, if the central control unit 10 decides to update the parameters for the 5GHz band, it restricts the selection of bandwidth b and channel c for APs using the 6GHz band. Specifically, for the 6GHz band used by APs using the 5GHz band, the currently used parameters are given priority.

[0064] Prioritizing selection may be achieved, for example, by fixing the currently used parameters. Alternatively, prioritizing selection may be achieved, for example, by replacing the utility function U related to the relevant AP with a utility function U', which is a function obtained by multiplying utility function U by a coefficient. The utility function U' is shown in equation 3.

[0065] a: AP identifier b: Bandwidth c: Channel (Primary Channel) R: Data Rate (MCS) A: Coefficient

[0066] This coefficient A is greater than 1 if (b, c) is a combination currently in use, and 1 if it is not a combination currently in use. In other words, if the combination of (b, c) is one currently in use, the corresponding (b, c) can be selected preferentially by making the value of the utility function U' larger.

[0067] Similarly, in step 210, if the central control unit 10 decides to update the parameters for the 5GHz band, it restricts the selection of bandwidth b and channel c for APs using the 6GHz band. Specifically, for the 6GHz band used by APs using the 5GHz band, it prioritizes selecting the parameters currently in use.

[0068] In this embodiment, the central control unit 10 is shown to perform parameter updates for the 5GHz and 6GHz bands at independent timings, but this embodiment is not limited to this. For example, the central control unit 10 may determine the wireless resources for the 5GHz and 6GHz bands separately and then perform parameter updates for both the 5GHz and 6GHz bands simultaneously. In this embodiment, since the number of communication interruptions does not increase in case (2), parameter updates for both the 5GHz and 6GHz bands may be performed.

[0069] Figure 6 shows the parameter update process for the comparative example. Referring to Figure 6, the advantages obtained by the RATOP algorithm according to this disclosure will be explained. The wireless communication system in the comparative example is assumed to have the same configuration as wireless communication system 100.

[0070] The centralized control device 10 in the comparative example determines wireless resources separately for each frequency band. Here, we show an example in which wireless resources are determined for the 5GHz band first, and then for the 6GHz band. The centralized control device 10 is assumed to have determined parameter updates for both the 5GHz and 6GHz bands based on the RATOP algorithm.

[0071] In case (1), the parameters for the 5GHz band are updated first, followed by the parameters for the 6GHz band. AP20a uses the 6GHz band in addition to the 5GHz band. Therefore, many wireless devices connected to AP20a will experience two communication interruptions due to the parameter updates for both the 5GHz and 6GHz bands. In particular, if AP20a and the terminal 40 under it are configured as an MLD, the communication interruptions occurring in both the 5GHz and 6GHz bands will result in the loss of the advantages obtained by the MLD configuration.

[0072] In case (2), the parameters for the 5GHz band are updated first, followed by the parameters for the 6GHz band. AP20a uses the 6GHz band in addition to the 5GHz band. Therefore, for many wireless devices connected to AP20a, two communication interruptions will occur across the entire AP due to the parameter updates for both the 5GHz and 6GHz bands.

[0073] As described above, in both cases (1) and (2), the centralized control device 10 in the comparative example experiences a temporary communication interruption due to parameter update processing, which occurs simultaneously in many wireless devices connected to each AP. This leads to the problem of unstable communication quality across the entire system.

[0074] In this embodiment, the central control device 10 restricts the selection of bandwidth b and channel c in the RATOP algorithm. Specifically, when it is decided to update parameters for the 5GHz band, the currently used parameters are prioritized for the 6GHz band used by APs using the 5GHz band. In other words, the parameter optimization algorithm is designed to reduce the number of frequency bands for which parameter updates occur for APs using multiple frequency bands. As a result, the frequency of communication interruptions can be reduced, thereby stabilizing the communication quality of the entire system.

[0075] Embodiment 2 Figure 7 is a diagram showing the options for allocating wireless resources according to Embodiment 2 of this disclosure. The centralized control device 10 according to this embodiment differs from Embodiment 1 in that it determines wireless resources for multiple wireless devices collectively and excludes or gives low priority to options that require parameter updates for all of the multiple wireless devices.

[0076] Note that in Figure 7, due to space limitations, the reference numerals that should be attached to AP20a, wireless devices 22a and 22b have been omitted.

[0077] The central control device 10 according to this embodiment allocates wireless resources according to the RATOP algorithm shown in Figure 5. However, in S202, 204, and 210, the central control device 10 restricts the selection of bandwidth b and channel c.

[0078] Specifically, the central control unit 10 first sets a list of combinations of parameters for the 5GHz band and parameters for the 6GHz band as options for bandwidth b and channel c. Furthermore, the central control unit 10 excludes or sets low priority options that require parameter updates for both the 5GHz and 6GHz bands, and selects one option from the combination list.

[0079] Figure 7 shows the options (a), (b), and (c) that the central control device 10 according to this embodiment can select. Option (a) is an option in which parameter updates are performed in the 5 GHz band, but not in the 6 GHz band. In other words, option (a) is not an option in which parameter updates are required for all of the multiple frequency bands. Therefore, the central control device 10 can select option (a) in either case (1) or (2).

[0080] Option (b) is an option to perform parameter updates in the 5GHz and 6GHz bands. In other words, option (b) is an option where parameter updates are required for all of the multiple frequency bands. Therefore, in both cases (1) and (2), the central control unit 10 excludes option (b) or gives it low priority.

[0081] Option (c) is an option in which parameter updates are performed in the 5GHz and 6GHz bands, and in which the parameter updates for the 5GHz and 6GHz bands are performed simultaneously. In other words, option (b) is an option in which parameter updates are required for all of the multiple frequency bands. For this reason, in case (1), the central control device 10 excludes option (c) or gives it low priority.

[0082] On the other hand, in case (2), even if the parameters for the 5GHz band and the 6GHz band are updated simultaneously, the number of communication interruptions will not increase. Therefore, in case (2), the central control unit 10 can select option (c).

[0083] As described above, the centralized control device according to this embodiment can stabilize the overall communication quality of the system by reducing the frequency of communication interruptions, even when wireless resources are determined collectively for multiple frequency bands.

[0084] Embodiment 3 Figure 8 is a diagram showing the allocation of wireless resources according to Embodiment 3 of the present disclosure. The central control device 10 according to this embodiment differs from Embodiments 1 and 2 in that, in case (2), it always updates the parameters of multiple frequency bands simultaneously.

[0085] The central control device 10 according to this embodiment allocates wireless resources using the method shown in Embodiment 1 or 2. If, as a result of allocating wireless resources, parameter updates become necessary in multiple frequency bands, the central control device 10 always performs parameter updates for multiple frequency bands simultaneously. As a result, the frequency of communication interruptions can be reduced, thereby stabilizing the communication quality of the entire system.

[0086] Embodiment 4 The central control device 10 according to this embodiment differs from Embodiments 1 to 3 in that it has under its control both an AP under which parameter updates are performed for each frequency band and an AP under which parameter updates are performed for each AP.

[0087] In this embodiment, the central control device 10 first acquires information on whether each AP under its control performs parameter updates per frequency band or per AP. This information may be acquired from the APs under its control, or it may be pre-configured by storing it in the internal memory of the central control device 10. Subsequently, the central control device 10 allocates wireless resources by performing different processing for each AP under its control based on the acquired information.

[0088] Specifically, the central control device 10 performs the processing shown in Embodiment 1 or 2 when the APs under its control perform parameter updates for each frequency band. Alternatively, the central control device 10 performs the processing shown in any one of Embodiments 1 to 3 when the APs under its control perform parameter updates for each AP. Note that when the APs under its control perform parameter updates for each AP, especially when parameter updates for multiple frequency bands are performed simultaneously, there is no need to restrict the parameters to be selected.

[0089] As described above, the centralized control device according to this embodiment can stabilize the overall communication quality of the system by reducing the frequency of communication interruptions, even when it has under its control both APs where parameter updates are performed per frequency band and APs where parameter updates are performed per AP.

[0090] The possible forms of disclosure are listed as an addendum.

[0091] [Note 1] A wireless communication system comprising: a plurality of APs equipped with a plurality of wireless devices; and a central control device that controls the parameters of the wireless devices according to the state of mutual interference between the plurality of wireless devices, wherein the control is performed to increase the probability that the channel currently in use is maintained for at least one of the plurality of wireless devices equipped with the AP. [Note 2] The wireless communication system according to Note 1, wherein the control is performed for each wireless device, and when a channel different from the currently in use is assigned to one of the plurality of wireless devices equipped with the AP, the wireless devices other than the wireless device are made to use the currently in use channel in a fixed manner. [Note 3] The wireless communication system according to Note 1, wherein the control is performed for each wireless device, and when a channel different from the currently in use is assigned to one of the plurality of wireless devices equipped with the AP, the wireless devices other than the wireless device are made to use the currently in use channel preferentially. [Note 4] The wireless communication system described in Note 1, wherein the control is performed simultaneously for all wireless devices and is realized by performing the following: setting a list of parameter combinations including assignable channels for each of the multiple wireless devices mounted on the AP; and selecting one wireless channel from the combination list, excluding or giving low priority to the option of having all wireless devices mounted on the AP use a channel other than the one currently in use. [Note 5] The wireless communication system described in Note 1, wherein the control is performed for each wireless device and, when assigning a channel different from the currently in use to one of the multiple wireless devices mounted on the AP, the process is performed by collecting information on whether the AP is an AP that performs parameter updates for each AP; and for APs that perform parameter updates for each AP, the process is performed to simultaneously update the multiple wireless devices mounted on the AP.

[0092] 10 Centralized control unit 20a AP 20b AP 20c AP 22a Wireless device 22b Wireless device 40 Terminal 100 Wireless communication system

Claims

1. A communication device for controlling an AP using at least one or more wireless devices, comprising: a first process of setting one or more parameters including a channel assignable to the AP; a second process of calculating a utility function for each of the parameters; a third process of selecting the optimal parameters based on the results of the calculation; and a process of repeating the first process, the second process and the third process so as to apply to each of the at least one AP, wherein the first process is performed in such a way that the probability of maintaining the parameters currently in use is increased for at least one of the multiple wireless devices.

2. The communication device according to claim 1, wherein the first process is a process in which, when it is decided to update the parameters of at least one of the plurality of wireless devices, the currently used parameters are preferentially selected for at least one of the wireless devices other than said wireless device.

3. The communication device according to claim 1, wherein the first process is achieved by performing the process of setting a list of parameter combinations including the assignable channels in each of the plurality of wireless devices, and the process of selecting one option from the combination list, excluding or lowering priority options for which all of the plurality of wireless devices require parameter updates.

4. A method to be performed by a communication device that controls an AP using at least one or more wireless devices, comprising: setting one or more parameters including channels that can be assigned to the AP; calculating a utility function for each of the parameters; selecting the optimal parameter based on the result of the calculation; and repeating the setting, calculation, and selection so that each of the at least one AP is targeted, wherein the setting is performed in such a way that the probability of maintaining the parameters currently in use is high for at least one of the multiple wireless devices.

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