Radio resource control system, radio resource control device, radio resource control method, and radio resource control program

Abstract

Provided is a radio resource control system for controlling radio resources for a plurality of aggressor radio devices 12-1 and 12-2 that cause interference in victim radio devices 20-1 and 20-2 of which communication quality should be protected. Included is a radio resource control device 34 that executes a resource inquiry (11) for inquiring regarding available radio resources, as a representative of the plurality of aggressor radio devices 12-1 and 12-2. Included is an AFC server 18 that, in response to the request inquiry, provides the radio resource control device 34 with information of radio resources that can be used by the aggressor radio devices 12-1 and 12-2 within a range in which the amount of interference that the victim radio devices 20-1 and 20-2 are subjected to is no greater than an admissible value, as a response (13). The radio resource control device 34 executes resource centralized control (14) with respect to the plurality of aggressor radio devices 12-1 and 12-2 within a range of the radio resources included in the response.

Description

Radio resource control system, radio resource control device, radio resource control method, and radio resource control program

[0001] This disclosure relates to a radio resource control system, a radio resource control device, a radio resource control method, and a radio resource control program, and in particular to a radio resource control system, a radio resource control device, a radio resource control method, and a radio resource control program that are suitable for efficiently centrally controlling radio resources for multiple interfering radio devices while minimizing the impact on an interfered radio device to be protected.

[0002] In a wireless communication environment, an interfered wireless device to be protected and an interfering wireless device emitting an interfering signal may be installed close to each other. In such an environment, AFC (Automated Frequency Coordination) for wireless LANs is known as a method for controlling wireless resources allocated to the interfering wireless device so that the amount of interference to the interfered wireless device falls within a tolerable value. Basic information about AFC is disclosed in, for example, the following non-patent documents 1 and 2.

[0003] In a system using AFC, each of multiple interfering wireless devices (hereinafter referred to as "APs" (Access Points)) sends a query message regarding the use of wireless resources to an AFC server via a network. The query message includes the AP's location information, the frequency range it wishes to use, and the required amount of transmission power. The AFC server determines the range of wireless resources to be granted to the AP so that the amount of interference experienced by the interfered wireless device falls within a predetermined tolerance, and returns the result to the AP as a response.

[0004] The AP that receives the response communicates with the wireless terminals under its control using the wireless resources permitted by the AFC server. As long as each AP uses the resources permitted by the AFC server, the amount of interference experienced by the interfered wireless device can be kept below the allowable value. Therefore, a system using AFC can appropriately protect the communications of the interfered wireless device.

[0005] “DRAFT AFC System to AFC Device Interface Specification”, Version 0.1.17, 2021, Wi-Fi Alliance“Wi-Fi Alliance furthers Automated Frequency Coordination specification and compliance development to accelerate Wi-Fi 6E”, 2022, Wi-Fi Alliance, <URL: https: / / www.wi-fi.org / news-events / newsroom / wi-fi-alliance-furthers-automated-frequency-coordination-specification-and>

[0006] In a system that uses AFC to share frequencies, multiple APs individually send inquiry messages about wireless resources to an AFC server. The AFC server considers the impact on the interfered wireless device, but replies to each AP without considering interference between multiple APs. This can result in overlapping resources used by multiple APs, which can lead to situations where the amount of interference and throughput for each AP are not optimized.

[0007] In order to solve the above-mentioned problems, a first object of the present disclosure is to provide a radio resource control system that efficiently allocates radio resources to multiple interfering radio devices while keeping the impact on the interfered radio device to be protected within an acceptable range.

[0008] A second object of the present disclosure is to provide a radio resource control device that efficiently allocates radio resources to a plurality of interfering radio devices while keeping the impact on an interfered radio device to be protected within an acceptable range.

[0009] A third object of the present disclosure is to provide a radio resource control method for efficiently allocating radio resources to a plurality of interfering radio devices while keeping the impact on the interfered radio device to be protected within an acceptable range.

[0010] A fourth object of the present disclosure is to provide a radio resource control program for efficiently allocating radio resources to multiple interfering radio devices while keeping the impact on the interfered radio device to be protected within an acceptable range.

[0011] A first aspect is a radio resource control system for controlling radio resources for a plurality of interfering radio devices that cause interference to an interfered radio device whose communication quality should be protected, comprising: a radio resource control device that executes a resource inquiry to inquire about available radio resources on behalf of the plurality of interfering radio devices; and a frequency coordination server that receives the resource inquiry and provides, in response to the radio resource control device, information on radio resources that the interfering radio devices can use within a range in which the amount of interference experienced by the interfered radio device is within an allowable value, and it is desirable that the radio resource control device is configured to execute centralized resource control for the plurality of interfering radio devices within the range of the radio resources included in the response.

[0012] Furthermore, a second aspect is a radio resource control device for controlling radio resources for a plurality of interfering radio devices that cause interference to an interfered radio device whose communication quality should be protected, and is desirably configured to perform the following: a resource inquiry to inquire of a frequency coordination server about radio resources that can be used on behalf of the plurality of interfering radio devices; receiving a response generated by the frequency coordination server in response to the resource inquiry, the response including information on radio resources that can be used by the interfering radio devices within a range in which the amount of interference experienced by the interfered radio device is within an allowable value; and centralized resource control for the plurality of interfering radio devices within the range of radio resources included in the response.

[0013] Furthermore, a third aspect is a radio resource control method for controlling radio resources for a plurality of interfering radio devices that cause interference to an interfered radio device whose communication quality should be protected, and preferably includes the steps of: a radio resource control device representing the plurality of interfering radio devices executing a resource inquiry to inquire about radio resources available for use by the plurality of interfering radio devices; a frequency coordination server receiving the resource inquiry and responding to the radio resource control device with information about radio resources available for use by the interfering radio devices within a range in which the amount of interference experienced by the interfered radio device is within an allowable value; and a radio resource control device executing centralized resource control for the plurality of interfering radio devices within the range of radio resources included in the response.

[0014] Furthermore, a fourth aspect is a radio resource control program for causing a computer to execute radio resources for a plurality of interfering radio devices that cause interference to an interfered radio device whose communication quality should be protected, and it is desirable that the program includes the following: a resource inquiry for inquiring of a frequency coordination server about radio resources that can be used on behalf of the plurality of interfering radio devices; reception of a response generated by the frequency coordination server in response to the resource inquiry, the response including information on radio resources that can be used by the interfering radio device within a range in which the amount of interference experienced by the interfered radio device is within an allowable value; and centralized resource control for the plurality of interfering radio devices within the range of radio resources included in the response.

[0015] According to the first to fourth aspects, by coordinating the centralized control of radio resources for multiple interfering radio devices with the radio resource control for protecting the interfered radio device, it is possible to optimize the entire system including the interfered radio device and multiple interfering radio devices.

[0016] FIG. 1 is a diagram illustrating an example of a system using AFC. FIG. 1 is a diagram illustrating a configuration of a radio resource control system according to a first embodiment of the present disclosure. FIG. 2 is a block diagram illustrating a hardware configuration of the radio resource control device shown in FIG. 1. FIG. 3 is a flowchart illustrating a process flow performed by the radio resource control device shown in FIG. 1. FIG. 4 is a diagram illustrating a configuration of a radio resource control system according to a second embodiment of the present disclosure. FIG. 5 is a flowchart illustrating a process flow performed by the radio resource control device shown in FIG. 7. FIG. 6 is a diagram illustrating a configuration of a radio resource control system according to a fourth embodiment of the present disclosure. FIG. 9 is a flowchart illustrating a process flow performed by the radio resource control device shown in FIG. 9. FIG. 7 is a diagram illustrating a configuration of a radio resource control system according to a fifth embodiment of the present disclosure. FIG. 8 is a flowchart illustrating a process flow performed by the radio resource control device shown in FIG.

[0017] First Embodiment [An Example of an AFC System] As a premise of a radio resource control system according to an embodiment of the present disclosure, a system using AFC will be described first. Fig. 1 is a diagram for explaining an example of a system using AFC.

[0018] The AFC system 10 shown in Figure 1 includes multiple interfering devices 12-1 and 12-2. Hereinafter, the interfering devices will be referred to as "APs." Furthermore, when there is no need to distinguish between the multiple APs 12-1 and 12-2, the subscripts of the reference symbols will be omitted and the APs will be referred to as "AP 12."

[0019] Each AP 12 is connected to a public network 16 via a relay device 14. An AFC server 18 is connected to the public network 16. Each AP 12 can communicate with the AFC server 18 via the relay device 14.

[0020] 1 includes a plurality of interfered radio devices 20-1 and 20-2 in addition to the AFC system 10. Hereinafter, when there is no need to distinguish between the interfered radio devices 20-1 and 20-2, the subscripts of the reference symbols will be omitted and the interfered radio devices will be referred to as "interfered radio devices 20."

[0021] The interfered wireless device 20 is a device whose communication quality needs to be protected. However, the frequency band used by the interfered wireless device 20 for communication may overlap with the frequency band used by the AP 12. If the AP 12 freely uses wireless resources in such an environment, the communication waves transmitted and received by the AP 12 may become interference waves for the interfered wireless device 20, and the communication of the interfered wireless device 20 may be disrupted.

[0022] To avoid such a situation, the AFC server 18 instructs the AP 12 on available wireless resources so that the amount of interference with the interfered wireless device 20 is kept below an allowable value. The lower part of Fig. 1 shows the flow of inquiries and responses regarding wireless resources exchanged between the AP 12 and the AFC server 18.

[0023] According to AFC, first, an AFC message is sent from an AP 12 for resource inquiry (Step 1). Resource inquiry is performed individually by each of the multiple APs 12. Here, it is assumed that AP 12-1 has issued the resource inquiry. The AFC message includes the location of the AP 12-1 that sent the message, the frequency range it requests to use, the required amount of transmission power, etc.

[0024] In the example shown in FIG. 1, the resource inquiry sent from the AP 12-1 is delivered to the AFC server 18 via the relay device 14 (step 2).

[0025] The AFC server 18 has registered in advance the location of the interfered radio device 20, the frequency band used by the interfered radio device 20, the allowable amount of interference in the interfered radio device 20, etc. Based on the location of AP 12-1 and other information contained in the received AFC message, the AFC server 18 determines whether the amount of interference experienced by the interfered radio device 20 is within the allowable amount using the radio resources requested by AP 12-1 (step 3).

[0026] The AFC server 18 returns a response to the resource inquiry based on the result of the determination (step 4). Specifically, if the use of the wireless resources requested by AP 12-1 will not cause the interfered wireless device 20 to experience an amount of interference that exceeds the allowable value, the AFC server 18 returns a response of "permitted" to the resource inquiry. On the other hand, if the amount of interference that exceeds the allowable value is predicted to occur, the AFC server 18 returns a response of "not permitted" or an allowable wireless resource.

[0027] The relay device 14 transmits the response received from the AFC server 18 to the AP 12-1. As a result, resource control for the AP 12-1 is implemented (step 5). Thereafter, the AP 12-1 communicates with the wireless terminals under its control using the wireless resources permitted by the received response.

[0028] The above processing is also performed for AP 12-2. As a result, the amount of interference experienced by the interfered wireless device 20 is kept below the allowable value, and the communications of the interfered wireless device 20 are appropriately protected. On the other hand, the AFC server 18 provides responses to AP 12-1 and AP 12-2 that are determined without considering interference between APs 12. For this reason, a situation may arise in which each AP 12 is unable to obtain satisfactory communication quality due to interference from other APs 12.

[0029] [Configuration of First Embodiment] Figure 2 is a diagram for explaining a radio resource control system according to a first embodiment of the present disclosure. The system of this embodiment has a function of solving the above-mentioned problems of the AFC system 10 shown in Figure 1. In Figure 2, elements that are the same as or correspond to elements shown in Figure 1 are assigned the same reference numerals, and their description will be simplified or omitted.

[0030] As shown in Fig. 2, the system of this embodiment has a configuration in which an AFC system 30 and a centralized control system for radio resources 32 are linked together. The link between the two is achieved by replacing the relay device 14 shown in Fig. 1 with a radio resource control device 34.

[0031] The radio resource control device 34 functions as an AFC representative device that performs resource inquiries on behalf of multiple APs 12. The radio resource control device 34 also functions as a centralized control device that appropriately allocates radio resources to multiple APs 12.

[0032] The operation of the radio resource control system of this embodiment will be described below with reference to the chart shown in the lower part of Fig. 2. In the system of this embodiment, the locations of all APs 12 belonging to the radio resource control device 34 are registered in advance. If it is necessary to ensure the accuracy of the location information, each AP 12 may be equipped with a GPS function and the AP 12 may report its location information to the radio resource control device 34.

[0033] When the time for resource inquiry arrives, the radio resource control device 34 performs resource inquiry on behalf of all APs 12 under its control (step 11). Specifically, on behalf of all APs 12, the radio resource control device 34 transmits an AFC message including the frequency range to be used and the required amount of transmission power to the AFC server 18.

[0034] 1, information on the location and amount of interference related to the interfered radio device 20 is registered in the AFC server 18. Based on the received AFC message, the AFC server 18 determines whether the queried radio resource is one that keeps the amount of interference from the interfered radio device 20 below an allowable value (step 12).

[0035] Depending on the result of the above determination, the AFC server 18 returns an AFC message to the radio resource control device 34 as a response, informing it of the radio resources that are permitted to be used (step 13). Specifically, this AFC message includes the available frequency bands (e.g., f1, f2), the upper limit of the transmission power for each frequency band (e.g., f1, f2), the expiration date of the permission to use, etc.

[0036] Upon receiving the response, the radio resource control device 34 performs centralized resource control for all APs under its control (step 14). Specifically, the authorized radio resources are allocated to the APs 12 under its control so as to be utilized most efficiently. More specifically, in the centralized resource control, radio resources are allocated to each AP 12 within the range of the authorized radio resources so as to prevent interference between the multiple APs 12 under its control. For example, in the situation shown in FIG. 2, frequency band f1 (and its transmission power) is allocated to AP 12-1, and frequency band f2 (and its transmission power) is allocated to AP 12-2.

[0037] The AFC server 18 manages radio resources to keep the amount of interference from the interfered radio device 20 below an allowable value. Therefore, frequency bands that do not interfere with the interfered radio device 20, that is, frequency bands that are not used by the interfered radio device 20, are not subject to management by the AFC server 18. Furthermore, frequency bands that are not subject to management do not affect the protection of the interfered radio device 20 even if permission has not been granted by the AFC server 18. For this reason, the radio resource control device 34 may allocate radio resources (frequency bands) that are not subject to management by the AFC server 18 to the subordinate APs 12 as necessary, in addition to the radio resources that have been granted permission by the AFC server 18.

[0038] In the configuration shown in Fig. 2, failures may occur in individual APs 12 due to the influence of surrounding wireless devices, etc. In order to eliminate the influence of such failures early, it is effective to periodically provide an opportunity to review resources and update wireless resources as necessary.

[0039] Therefore, in this embodiment, the centralized resource control is periodically and repeatedly executed for the AP 12. The chart in the lower part of Fig. 2 shows how the centralized resource control (step 14) is repeatedly executed at each "centralized control interval."

[0040] In order for the radio resource control device 34 to perform centralized resource control at the time when the "centralized control interval" has elapsed, it is necessary that the radio resource control device 34 has received a response from the AFC server 18 at that time. The response then arrives at the radio resource control device 34 after the "required inquiry time" including the calculation time of the AFC server 18 has elapsed since the radio resource control device 34 made a resource inquiry.

[0041] For this reason, in this embodiment, after performing centralized resource control for the AP 12, the radio resource control device 34 first reads out information about the predetermined "centralized control interval." Next, it estimates the "required inquiry time" including the calculation time of the AFC server 18. Then, it calculates the inquiry timing shown in the following formula 1, and waits for that timing to perform a new resource inquiry (step 15). Inquiry timing = (centralized control interval) - (required inquiry time) ... (formula 1)

[0042] Thereafter, the radio resource control device 34 receives a response (step 13) from the AFC server 18 and performs centralized resource control (15). As a result, centralized resource control for the AP 12 is periodically and repeatedly executed at each centralized control interval.

[0043] [Hardware Configuration of Radio Resource Control Device] Fig. 3 is a diagram illustrating the hardware configuration of the radio resource control device 34 of this embodiment. As shown in Fig. 3, the radio resource control device 34 includes a processor 36. The processor 36 is connected to a ROM 40, a RAM 42, and a storage 44 such as a hard disk via a communication path 38. In addition to a communication interface 46 and an input / output interface 48, dedicated hardware 50 is also connected to the communication path 38 as needed.

[0044] 3 is merely an example, and the functions realized by the configurations described herein may be implemented in circuitry or processing circuitry including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), a Central Processing Unit (CPU), conventional circuits, and / or combinations thereof, all programmed to realize the described functions. The processor 36 includes transistors and other circuits and is considered to be circuitry or processing circuitry. The processor may also be a programmed processor that executes programs stored in various memories.

[0045] In this specification, a circuit, a "part," a "unit," or a "means" refers to hardware that is programmed to implement a described function or that implements that function, and may be any hardware disclosed herein or any hardware that is programmed to implement the described function or that is known to execute that program.

[0046] If the hardware is a processor, which is considered to be a type of circuitry, then the circuitry, "part" or "unit" or "means" is the combination of the hardware and software used to configure the hardware and / or processor.

[0047] [Processing Flow in Embodiment 1] Fig. 4 is a flowchart for explaining the processing flow executed by the radio resource control device 34 in this embodiment. In the routine shown in Fig. 4, first, it is determined whether or not an inquiry trigger has occurred (step 100). Except for the first time, an inquiry trigger occurs at each inquiry timing calculated by the above (Equation 1). This processing corresponds to (step 11) and (step 15) shown in Fig. 2.

[0048] If it is determined that a query trigger has occurred, then a resource query is made to the AFC server 18 (step 102). This process corresponds to the process shown in FIG. 2 (step 11).

[0049] Next, it is determined whether a response has been received from the AFC server 18 (step 104).

[0050] If the response is received, centralized control of wireless resources for all APs 12 is performed within the range of wireless resources permitted for use (step 106). This process corresponds to step 14 shown in FIG. 2.

[0051] After the above process is completed, the time required from making an inquiry to the AFC server 18 until a response is received is acquired as the "inquiry time" in preparation for the next routine (step 108). Thereafter, the processes of steps 100 to 108 are repeatedly executed.

[0052] According to the above processing, the AFC function can be used to appropriately protect the communications of the interfered radio device 20, while allocating radio resources to multiple APs 12 so as not to cause mutual interference. Therefore, the radio resource control device 34 of this embodiment can achieve overall optimization in a system including the interfered radio device 20 and multiple interfering radio devices 12.

[0053] Second Embodiment. [Configuration of Second Embodiment] Next, a second embodiment of the present disclosure will be described with reference to Figures 5 and 6. Figure 5 is a diagram for explaining a radio resource control system according to the second embodiment of the present disclosure. The configuration shown in Figure 5 is similar to the configuration shown in Figure 2, except that the radio resource control device 34 is replaced with a radio resource control device 52, and the AP 12 includes four APs, AP 12-1 to AP 12-4. Note that in Figure 5, elements that are the same as or correspond to elements shown in Figure 2 are assigned the same reference numerals, and their description will be omitted or simplified.

[0054] As in the first embodiment, the location information of all APs under its control is registered in the radio resource control device 52. In the example shown in Fig. 5, APs 12-1 and 12-2 are located relatively close to each other, and APs 12-3 and 12-4 are also located relatively close to each other.

[0055] The AFC server 18 grants each AP 12 wireless resources that do not cause excessive interference to the interfered wireless device 20. The degree of interference caused to the interfered wireless device 20 by the AP 12 using a specific wireless resource is greatly affected by the relative positions of the AP 12 and the interfered wireless device 20. For this reason, the wireless resources granted to multiple APs 12 located close to each other will inevitably be similar. On the other hand, the wireless resources granted to multiple APs 12 located far from each other will likely be different.

[0056] In this embodiment, such characteristics are utilized to group multiple APs 12 that are located close to each other into a single area, and a resource inquiry is performed for each area. The chart shown in the lower part of Fig. 5 illustrates an example in which the radio resource control device 52 groups APs 12-1 and 12-2 into area 54-1 and APs 12-3 and 12-4 into area 54-2 based on the location information of the APs 12, and then performs a resource inquiry for each area.

[0057] 5, when resource inquiries are made for each area, the frequency of inquiries is reduced compared to when resource inquiries are made for each AP 12. Therefore, according to the system of this embodiment, it is possible to reduce the load associated with resource inquiries on both the radio resource control device 52 and the AFC server 18.

[0058] [Processing Flow in Embodiment 2] Fig. 6 is a flowchart for explaining the processing flow executed by the radio resource control device 52 in this embodiment. In the routine shown in Fig. 6, first, location information of all APs belonging to the control unit is acquired (step 110).

[0059] Next, areas are set based on the location information of the AP 12 (step 112). Each area is defined by its size, shape (circular or polygonal), and location (e.g., its center position). If multiple areas are set, an area number is assigned to each area.

[0060] After the above process is completed, it is determined whether or not a query trigger has occurred for area i (i is any area number) (step 114). It is assumed that a query trigger occurs for each area in the same way as in the first embodiment.

[0061] When it is determined that a query trigger has occurred, a resource query for area i is performed (step 116). In this embodiment, the resource query includes information defined for area i, such as its size, shape, and location, in the AFC message. The AFC server 18 returns a response containing wireless resources that are permitted for use within area i, taking into account the entire area i, rather than the locations of individual APs 12 included in area i.

[0062] The radio resource control device 52 then determines whether or not a response has been received from the AFC server 18 (step 118).

[0063] If it is determined that a response has been received, centralized control of wireless resources is performed for all APs 12 belonging to area i within the range of wireless resources permitted for use (step 120).

[0064] After the above process is completed, the time required from the inquiry to the response is acquired as the "inquiry time" for area i in preparation for the next routine (step 122). Thereafter, the processes of steps 110 to 112 are repeatedly executed, thereby performing resource inquiry and centralized resource control for all areas. Note that the processes of steps 110 and 112 may be executed only when there is an increase or decrease in the number of APs 12 subordinate to the radio resource control device 52, except for the initial process.

[0065] According to the above process, as in the first embodiment, it is possible to realize overall optimization in a system including the interfered radio device 20 and all of the interfering radio devices 12. Furthermore, by performing resource inquiries for each area, it is possible to reduce the load associated with resource inquiries compared to the first embodiment.

[0066] Third Embodiment Next, a third embodiment of the present disclosure will be described with reference to Figures 7 and 8. Figure 7 is a diagram for explaining a radio resource control system according to the third embodiment of the present disclosure. The configuration shown in Figure 7 is the same as the configuration shown in Figure 2 except that the radio resource control device 34 is replaced with a radio resource control device 55. In Figure 7, elements that are the same as or correspond to elements shown in Figure 2 are denoted by the same reference numerals, and their description will be omitted or simplified.

[0067] In the second embodiment described above, the radio resource control device 52 groups multiple nearby APs 12 into the same area based on pre-registered location information. However, depending on the environment in which the APs 12 are located, multiple nearby APs 12 may have different effects on the interfered radio device 20. In such a situation, the amount of interference that the area will cause to the interfered radio device 20 may be overestimated, resulting in an unnecessary restriction on the radio resources that can be granted to the area.

[0068] Therefore, in this embodiment, the AFC server 18 first individually determines the wireless resources that can be granted to each AP 12, and then APs 12 that give similar responses are grouped together in the same area. If similar responses are obtained for multiple APs 12, it can be determined that the effects that these APs 12 have on the interfered wireless device 20 are similar. Therefore, by setting an area for each AP 12 that meets such conditions, it is possible to avoid a situation in which APs 12 that give different effects on the interfered wireless device 20 are mixed together in the same area.

[0069] 5 shows how a resource inquiry for AP 12-1 and a resource inquiry for AP 12-2 both resulted in a response permitting frequency band f1 and transmission power p1, and how a resource inquiry for AP 12-3 resulted in a response permitting frequency band f2 and transmission power p2.

[0070] In this case, since AP12-1 and AP12-2 are permitted to use the same frequency band f1 with the same transmission power p1, it can be determined that it is acceptable to perform resource inquiries for them collectively. On the other hand, since AP12-3 is permitted to use different wireless resources, it can be determined that AP12-3 should not be grouped in the same area as AP12-1 and AP12-2.

[0071] 7 shows how, based on the above determination, the radio resource control device 55 groups AP 12-1 and AP 12-3 into the same area 56, while excluding AP 12-3 from the area 56. As shown in the figure, the radio resource control device 55 then performs resource inquiries for the area 56 as a whole, and separately performs resource inquiries for AP 12-3. This allows the system of this embodiment to avoid the coexistence of multiple APs 12 with different effects in the same area, while achieving the effect of reducing the load associated with resource inquiries compared to the first embodiment.

[0072] [Processing Flow in Embodiment 3] Fig. 8 is a flowchart for explaining the processing flow executed by the radio resource control device 55 for area setting in this embodiment. In this embodiment, the radio resource control device 55 sets an area by the routine shown in Fig. 8, and then performs resource inquiry and centralized resource control by the processing of steps 114 to 122 shown in Fig. 6.

[0073] 8, first, it is determined whether an area setting trigger has occurred (step 130). The area setting trigger occurs when control is started and when the number of APs 12 under the control of the radio resource control device 55 increases or decreases.

[0074] If the occurrence of the area setting trigger is recognized, a resource inquiry is performed for the i-th AP 12 (step 132).

[0075] Next, it is determined whether a response for the i-th AP 12 has been received from the AFC server 18 (step 134).

[0076] If it is determined that a response has been received, it is then determined whether resource inquiries and response reception have been completed for all of the subordinate APs 12 (step 136).

[0077] As a result, if it is determined that the processing has not yet been completed for all APs 12, i is incremented and the processing from step 132 onwards is repeated again.

[0078] On the other hand, if it is determined in step 136 that processing has been completed for all APs 12, a grouping process is performed to group APs 12 that have obtained similar responses into one area (step 138). Whether the responses are similar or not is determined based on whether the frequency bands are the same and whether the transmission powers can be considered to be the same. Specifically, responses in different frequency bands are determined to be non-similar. Furthermore, even if the frequency bands are the same, responses in which the transmission powers differ by more than a predetermined threshold are determined to be non-similar. On the other hand, responses in the same frequency band and in which the difference in transmission power is within a threshold are determined to be similar.

[0079] Next, multiple APs 12 that have received responses that are deemed similar are grouped into the same area. APs 12 that have not received responses that are deemed similar are not assigned an area and are individually subject to resource inquiries.

[0080] 6 is performed, overall optimization is achieved in the system including the interfered radio device 20 and all of the interfering radio devices 12, just as in the case of embodiment 1. Furthermore, since it is possible to prevent APs 12 that have a different type of effect on the interfered radio device 20 from being mixed in the same area, it is possible to achieve the above overall optimization at an even higher level than in the case of embodiment 2.

[0081] Fourth Embodiment Next, a fourth embodiment of the present disclosure will be described with reference to Figures 9 and 10. Figure 9 is a diagram for explaining a radio resource control system according to the fourth embodiment of the present disclosure. The configuration shown in Figure 9 is the same as the configuration shown in Figure 5 except that the radio resource control device 52 is replaced with a radio resource control device 58. In Figure 9, elements that are the same as or correspond to elements shown in Figure 5 are denoted by the same reference numerals, and their description will be omitted or simplified.

[0082] In the system of this embodiment, resource inquiries are performed by grouping APs 12 that are located close to each other into one area, as in the case of embodiment 2. Fig. 9 shows an example in which the radio resource control device 58 groups APs 12-1 and 12-2 into area 54-1 based on location information, and groups APs 12-3 and 12-4 into area 54-2.

[0083] Incidentally, the multiple APs 12 operate in different environments. For example, AP 12-1 may be placed in an environment surrounded by many wireless devices, while AP 12-2 may be placed in an environment where no interfering devices exist nearby. In this case, even if the effects of both APs on the interfered wireless device 20 are the same, a situation may arise in which the expiration date of the wireless resources allocated to AP 12-1 must be set shorter than the useful life of the wireless resources allocated to AP 12-2.

[0084] As described above, the AFC server 18 has the function of including the expiration date for the use of wireless resources in the AFC message sent to the AP 12. The chart in the lower part of Fig. 9 shows how, using this function, the AFC server 18 returns a response to a resource inquiry for area 54-1 by setting an expiration date t1 for AP 12-1 and an expiration date t2 for AP 12-2. Here, however, it is assumed that t1<t2.

[0085] As described above, the radio resource control device 58 of this embodiment performs resource inquiries for each area, not for each AP, when multiple APs 12 are located in the same area, similar to the radio resource control device 52 of embodiment 2. However, unlike the radio resource control device 52 of embodiment 2, the radio resource control device 58 of this embodiment has a function of processing resource inquiries performed for each area when different expiration dates are set for each AP 12, using the following method.

[0086] In other words, when different expiration dates are set for multiple APs 12 belonging to the same area, the radio resource control device 58 of this embodiment has a function of selecting the shorter of those expiration dates and applying it to the centralized control interval for that area. In the example shown in Figure 9, of the two expiration dates t1 and t2 included in the response to the resource inquiry for area 54-1, the shorter t1 is set as the "centralized control interval."

[0087] Then, after performing centralized resource control for area 54-1, the radio resource control device 58 performs a new resource inquiry for area 54-1 when the time calculated by subtracting the inquiry time from the centralized control interval t1 has elapsed. This process allows repeated resource inquiries to be made for the AP 12 that requests the shortest interval when multiple APs 12 with different radio resource update intervals exist within the same area. Therefore, this embodiment can achieve both the function of performing resource inquiries for each area and the function of appropriately performing resource updates for all APs 12.

[0088] Furthermore, the radio resource control device 58 of this embodiment also has a function of expanding or contracting the inquiry time depending on the load on the AFC server 18. The time required for the AFC server 18 to understand the content of a resource inquiry and generate an appropriate response varies depending on the number of APs 12 that are the target of the resource inquiry, etc. In this embodiment, this variation is taken into account in order to improve the accuracy of the timing of the resource inquiry. Therefore, this embodiment can effectively avoid the inconvenience of a response not being returned to the radio resource control device 58 in an appropriate time due to a high load on the AFC server 18.

[0089] [Processing Flow in Embodiment 4] Fig. 10 is a flowchart for explaining the processing flow executed by the radio resource control device 34 in this embodiment. Note that, in the routine shown in Fig. 10, steps 110 to 120 are the same as the steps shown in Fig. 6, and therefore their explanation will be omitted or simplified here.

[0090] 10, an area is set by the processing of steps 110 to 112, and after centralized resource control is performed for area i by the processing of steps 114 to 120, the load on the AFC server 18 is estimated (step 150). This estimation may be performed, for example, by receiving information on the operating status from the AFC server 18. Alternatively, the load may be estimated from the number of APs 12 included in the resource inquiry target.

[0091] Next, the inquiry time required for area i is obtained based on the result of the load estimation for the AFC server 18 (step 152).

[0092] Next, the centralized control interval for area i is set (step 154). As described above, the shortest validity period included in the response to the AP 12 included in area i is set as the control interval.

[0093] After the above process is performed, in the next routine, in step 114, the centralized control interval set in step 154 ​​and the inquiry time acquired in step 152 are applied to the above (Equation 1) to determine the inquiry trigger for area i. As a result, a new resource inquiry for area i is performed at an appropriate timing determined based on the shortest validity period and taking into account the load on the AFC server 18.

[0094] [Modification of the Fourth Embodiment] Incidentally, in the fourth embodiment described above, area division is performed using the method of the second embodiment, but the present disclosure is not limited to this. The area division method may be the method of the third embodiment instead of the method of the second embodiment.

[0095] Furthermore, in the above-described fourth embodiment, the process of reflecting the load of the AFC server 18 in the required inquiry time is combined with a configuration in which a resource inquiry is performed for each area, but the present disclosure is not limited to this. If load fluctuations on the AFC server 18 are expected, the process of reflecting the load of the AFC server 18 in the required inquiry time may be combined with a configuration in which a resource inquiry is performed for each AP 12, as in the first embodiment.

[0096] Fifth Embodiment [Configuration of Fifth Embodiment] Next, a fifth embodiment of the present disclosure will be described with reference to Figures 11 and 12. Figure 11 is a diagram for explaining a radio resource control system according to a second embodiment of the present disclosure. The configuration shown in Figure 11 is the same as the configuration shown in Figure 2, except that the radio resource control device 34 is replaced with a radio resource control device 60. Note that in Figure 11, elements that are the same as or correspond to elements shown in Figure 2 are assigned the same reference numerals, and their description will be omitted or simplified.

[0097] In the above-described fourth embodiment, the radio resource control device 58 determines the timing of resource inquiry based on the expiration date (e.g., t1, t2) included in the response from the AFC server 18. The radio resource control device 60 of this embodiment estimates the state of the APs 12 belonging to its control, and determines the need for early update based on the result of the estimation.

[0098] The chart shown in the lower part of Fig. 11 shows how the radio resource control device 60 first performs resource inquiries for each AP 12 at predetermined timing, and then performs centralized resource control based on the received responses. This chart also shows the operation when the radio resource control device 60 predicts the occurrence of a communication failure in some APs 12. Hereinafter, the AP 12 in which a failure is predicted will be referred to as the "failure device."

[0099] For example, if the radio resource control device 60 detects the presence of a wireless device in the vicinity of AP 12-1 whose resources overlap with those of AP 12-1, it identifies AP 12-1 as a failed device. In this case, the radio resource control device 60 determines that the resources of the failed device need to be updated early, separately from those of the other APs 12. The chart in Figure 11 shows how, based on the above determination, the radio resource control device 60 sends an early inquiry targeting the failed device to the AFC server 18 and performs early resource control targeting the failed device based on the response received as a result.

[0100] In this embodiment, the APs 12 other than the failed device are subject to resource inquiry performed in response to the occurrence of an inquiry trigger and centralized resource control based on the resulting response, as in the first embodiment.

[0101] [Processing Flow in Embodiment 5] Fig. 12 is a flowchart for explaining the processing flow executed by the radio resource control device 60 in this embodiment. In the routine shown in Fig. 12, first, it is determined whether any of the subordinate APs 12 should be subject to early update (step 160). For example, an AP 12 that is predicted to experience a communication failure is determined to be subject to early update.

[0102] If the presence of an AP 12 to be the target of early update is not confirmed, step 162 is skipped and the process of step 164 is executed next. On the other hand, if the presence of an AP 12 to be the target of early update is confirmed, a centralized resource control interval for the AP 12 is set (step 162). The execution interval is set to be shorter, for example, the higher the possibility of communication failure occurring for the AP 12 to be the target of early update. More specifically, the execution interval is set to be shorter the greater the number of wireless devices present around the AP 12 and the greater the degree of overlap in the resources used by the surrounding wireless devices and the AP 12.

[0103] Once the above process is complete, it is then determined whether an early or regular query trigger has occurred (step 164). The occurrence of a trigger is determined substantially similarly to step 100 shown in FIG.

[0104] If an early query trigger is detected in step 164, a resource query is performed for the AP that is the target of the early update. If a normal query trigger is detected, a resource query is performed for the APs 12 other than the AP 12 that is the target of the early update (step 166). This process is performed substantially in the same manner as step 102 shown in FIG. 4.

[0105] Next, it is determined whether a response has been received from the AFC server 18 (step 168).

[0106] If the response is received, centralized resource control is performed on the AP 12 to be updated within the scope of the permission included in the response (step 170). For example, if the AP 12 to be updated is an AP 12 that requires an early update, the wireless resources of that AP 12 are updated. If the AP 12 to be updated is a normal AP 12, centralized resource control is performed on one or more normal APs 12.

[0107] Next, the response time required for the AP 12 to be updated is obtained (step 178). This process is executed substantially in the same manner as step 108 shown in Fig. 4. Thereafter, the processes of steps 160 to 178 are repeatedly executed.

[0108] According to the above process, when a faulty device is included among a plurality of APs 12 under the control of the radio resource control device 60, it is possible to quickly update only the radio resources of the faulty device, rather than treating all APs 12 uniformly. Furthermore, the radio resource control device 60 centrally controls the radio resources of the other normal APs 12, taking into consideration the radio resources allocated to the faulty device. Therefore, according to the system of this embodiment, even when some APs 12 are faulty devices, it is possible to achieve overall optimization in the system including the interfered radio device 20 and all of the plurality of interfering radio devices 12.

[0109] [Variation of the Fifth Embodiment] In the fifth embodiment described above, the radio resource control device 60, as in the first embodiment, performs a resource inquiry without grouping the APs 12 belonging to it by area. However, the present disclosure is not limited to this. The process of performing an early resource inquiry only for a faulty device may be performed in combination with the process described in the second or third embodiment, that is, the process of performing a resource inquiry for each area including multiple APs 12. In this case, if one or more faulty devices are found in a certain area, only the faulty device may be extracted from that area and made the target of an early update, or the area including the faulty device itself may be made the target of an early update.

[0110] 12, 12-1 to 12-4: Interfering device (AP: Access Point) 18: AFC server 20, 20-1, 20-2: Interfered radio device 34, 52, 55, 58, 60: Radio resource control device 36: Processor 54-1, 54-2, 56: Area

Claims

1. A radio resource control system for controlling radio resources for a plurality of interfering radio devices that cause interference to an interfered radio device whose communication quality should be protected, comprising: a radio resource control device that executes a resource inquiry to inquire about available radio resources on behalf of the plurality of interfering radio devices; and a frequency coordination server that receives the resource inquiry and provides, in response to the radio resource control device, information on radio resources that the interfering radio devices can use within a range in which the amount of interference experienced by the interfered radio device is within an allowable value, wherein the radio resource control device is configured to execute centralized resource control for the plurality of interfering radio devices within the range of the radio resources included in the response.

2. The radio resource control system according to claim 1, wherein the radio resource control device is further configured to perform the following processes: acquiring location information of the plurality of interfering radio devices; and grouping the plurality of interfering radio devices into a plurality of different areas based on the location information; the resource inquiry is performed for each of the areas; and the resource centralized control is performed on the interfering radio devices belonging to the target area in response to a response to the resource inquiry for the target area.

3. The radio resource control system according to claim 1, wherein the radio resource control device is further configured to perform the following processes: execute an individual resource inquiry for each of a plurality of subordinate interfering radio devices; receive an individual response to the individual resource inquiry; and group the plurality of interfering radio devices into a plurality of different areas based on the similarity of the individual responses; the resource inquiry is executed for each of the areas; and the centralized resource control is executed for the interfering radio devices belonging to the target area upon receiving a response to the resource inquiry for the target area.

4. The radio resource control device is further configured to perform the following processes: a process of estimating the load of the frequency adjustment server; a process of estimating, based on the load, a query time required from executing the resource query to receiving the response; a process of acquiring a control interval, which is the execution period of the resource centralized control; and a process of determining the time obtained by subtracting the query time required from the control interval as a query trigger generation time; and the resource query following the resource centralized control is executed when the query trigger generation time has elapsed after the resource centralized control is executed. The radio resource control system of claim 1.

5. The radio resource control device is configured to further perform the following processes: extracting, from the plurality of interfering radio devices, an early update target that requires updating its radio resources earlier than other interfering radio devices; setting an early control interval, which is an execution period for applying the centralized resource control to the early update target based on the status of the early update target; and setting a control interval, which is an execution period for applying the centralized resource control to normal interfering radio devices other than the early update target; and the resource inquiry for the early update target is performed at a timing set based on the early control interval, and the resource inquiry for the normal interfering radio devices is performed at a timing set based on the control interval. The radio resource control system according to claim 1.

6. A radio resource control device for controlling radio resources for a plurality of interfering radio devices that cause interference to an interfered radio device whose communication quality should be protected, configured to perform the following: a resource inquiry to inquire of a frequency coordinating server about radio resources that can be used on behalf of the plurality of interfering radio devices; receiving a response generated by the frequency coordinating server in response to the resource inquiry, the response including information on radio resources that can be used by the interfering radio devices within a range in which the amount of interference experienced by the interfered radio device is within an allowable value; and centralized resource control for the plurality of interfering radio devices within the range of radio resources included in the response.

7. A radio resource control method for controlling radio resources for a plurality of interfering radio devices that cause interference to an interfered radio device whose communication quality should be protected, comprising: a step in which a radio resource control device representing the plurality of interfering radio devices executes a resource inquiry to inquire about radio resources available for use by the plurality of interfering radio devices; a step in which a frequency coordination server receives the resource inquiry and responds to the radio resource control device with information about radio resources that the interfering radio device can use within a range in which the amount of interference experienced by the interfered radio device is within an allowable value; and a step in which the radio resource control device executes centralized resource control for the plurality of interfering radio devices within the range of radio resources included in the response.

8. A radio resource control program for causing a computer to execute radio resources for multiple interfering radio devices that cause interference to an interfered radio device whose communication quality should be protected, the radio resource control program including a program for causing a computer to execute the following: a resource inquiry to inquire of a frequency coordination server about radio resources that can be used on behalf of the multiple interfering radio devices; reception of a response generated by the frequency coordination server in response to the resource inquiry, the response including information on radio resources that can be used by the interfering radio device within a range in which the amount of interference experienced by the interfered radio device is within an allowable value; and centralized resource control for the multiple interfering radio devices within the range of radio resources included in the response.

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