JP6605874B2 - Wireless resource allocation method and system, roadside system, and computer program - Google Patents

Description

  The present invention relates to a radio resource allocation method and the like.

  In order to perform wireless communication with mobile stations such as in-vehicle devices, many roadside devices are installed near intersections. When a plurality of roadside units use the same radio resource, radio mutual interference occurs. Therefore, it is desired to allocate radio resources to a plurality of roadside units so that interference does not occur as much as possible. Non-Patent Documents 1 and 2 disclose radio resource allocation methods.

Hirozumi Yamaguchi et al., “Radio Mutual Interference Arbitration Algorithm Suitable for Operation Scenarios of ITS Roadside Units Installed Closely”, Information Processing Society of Japan Research Report. ITS, 2014-ITS-59 (28), 1-8, 2014-11-13 Hirozumi Yamaguchi et al., “Space Division Scheduling Technology for Radio Interference Arbitration of Dense Base Stations”, Transactions of Information Processing Society of Japan, Vol. 55, no. 2, pp. 826-837, 2014

  Each of the plurality of target areas may be under the jurisdiction of a different institution, and each institution may be independently responsible for assigning radio resources to roadside units within the jurisdiction of the subject area. For example, when X and Y prefectures adjacent to each other are assumed as a plurality of target areas, an organization having jurisdiction over X prefecture decides radio resource allocation to roadside devices in X prefecture, and has another jurisdiction over Y prefecture. An institution may decide to allocate radio resources to roadside devices in Y prefecture.

  If an organization in each prefecture independently decides radio resource allocation considering only within its own prefecture, there is a risk of interference between roadside devices near the border between the prefectures X and Y. On the other hand, when an organization in each prefecture determines radio resource allocation in its own prefecture in consideration of radio resource allocation in other prefectures, operation unique to each prefecture becomes difficult. In addition, if the institution of each prefecture decides the radio resource allocation in its own prefecture considering the radio resource allocation of other prefectures, the amount of radio resources required in its own prefecture will increase significantly, or the radio resource allocation in its own prefecture There is a risk that the frequency of changes will increase.

  A technique for appropriately performing radio resource allocation in each of a plurality of areas is desired.

  The present invention from one viewpoint is a radio resource allocation method in a target area, in which at least part of the first radio resource is allocated to a first roadside device installed in a first area included in the target area. Allocating, allocating at least part of a second radio resource different from the first radio resource to a second roadside device installed in a second area included in the target area, the first The area is adjacent to the boundary of the target area, the second area is adjacent to the first area, and is further away from the boundary than the first area.

  Another aspect of the present invention is a roadside machine system, which is installed in a first area included in a target area, and a plurality of first roadside machines to which at least a part of a first radio resource is allocated; A plurality of second roadside devices installed in a second area included in the target area and assigned with at least a part of a second radio resource different from the first radio resource, the first area Is adjacent to the boundary of the target area, and the second area is adjacent to the first area and is further away from the boundary than the first area.

  Another aspect of the present invention is a radio resource allocation method, in which at least a part of a first radio resource is allocated to a first roadside device installed in a first area included in a first target area. Allocating at least part of a second radio resource different from the first radio resource to a second roadside device installed in a second area included in the first target area, and in the second target area Allocating at least a part of the fourth radio resource to a fourth roadside device installed in the included fourth area, to a fifth roadside device installed in the fifth area included in the second target area Allocating at least a part of a fifth radio resource different from the fourth radio resource, wherein the first area is adjacent to a boundary of the first target area, and the second area is the Adjacent to one area, farther from the boundary than the first area, the second target area is governed by an organization different from the first target area, is adjacent to the boundary, and the fourth area is The fifth area is adjacent to the boundary, is adjacent to the fourth area, and is further away from the boundary than the fourth area.

  From another viewpoint, the present invention is a computer program for causing a computer to function as a processing unit and a storage unit that stores area information indicating the positions of the first area and the second area included in the target area. The first area is adjacent to the boundary of the target area, the second area is adjacent to the first area, and is further away from the boundary than the first area, and the processing unit is a roadside machine. Is acquired, and based on the area information, if it is determined that the installation position of the roadside machine indicated by the position information is included in the first area, the roadside machine is assigned a first allocation process. And determining that the installation location of the roadside device indicated by the location information is included in the second area based on the area information, the second allocation process is performed. The first allocation process is a process of allocating at least a part of the first radio resource to a roadside device installed in the first area, and the second allocation is performed. The process is a process of assigning at least a part of a second radio resource different from the first radio resource to a roadside device installed in the second area.

  Another aspect of the present invention is a radio resource allocation method, which allocates at least a part of a first radio resource to a first roadside device installed in a first area based on a first algorithm. Allocating at least a part of a second radio resource to a second roadside machine installed in a second area having a higher roadside machine installation density than the first area based on a second algorithm, The one algorithm obtains an interference relationship between the plurality of first roadside devices based on the installation positions of the plurality of first roadside devices, and determines which radio included in the first radio resource to the first roadside device. The second algorithm is an algorithm for determining whether a resource is allocated, and the second algorithm is arranged for each of a plurality of partial areas obtained by dividing an area where the second roadside device is installed. Which radio resource is allocated included in the scan is Arigorizumu which is predetermined.

  Another aspect of the present invention is a radio resource allocation system, which is a process of allocating at least a part of a first radio resource to a first roadside device installed in a first area based on a first algorithm. A process of allocating at least a part of the second radio resource to a second roadside machine installed in a second area having a higher roadside machine installation density than the first area, based on the second algorithm. The first algorithm is configured to obtain an interference relationship between the plurality of first roadside machines based on the installation positions of the plurality of first roadside machines, and to the first roadside machine, It is an algorithm for determining which radio resource included in the first radio resource is allocated, and the second algorithm is a plurality of sections that divide an area where the second roadside unit is installed. For each partial area, what radio resources are assigned included in the second radio resource is a Arigorizumu determined in advance.

  According to another aspect of the present invention, a process for allocating at least a part of a first radio resource to a first roadside device installed in a first area based on a first algorithm and a second algorithm And a process for allocating at least a part of the second radio resource to a second roadside machine installed in a second area having a higher roadside machine installation density than the first area. A computer program, wherein the first algorithm obtains an interference relationship between the plurality of first roadside machines based on installation positions of the plurality of first roadside machines, and sends the first roadside machine to the first roadside machine; This is an algorithm for determining which radio resource included in a radio resource is allocated, and the second algorithm is a complex that divides an area where the second roadside device is installed. For each partial area of, what radio resources are assigned included in the second radio resource is a Arigorizumu determined in advance.

It is a block diagram of a radio | wireless resource allocation system. It is a radio | wireless resource allocation figure of prefectural border vicinity. It is a figure which shows the change of the resource amount and resource change rate with respect to the increase in installation density. It is a radio | wireless resource allocation figure of prefectural border vicinity. It is a radio | wireless resource allocation figure of prefectural border vicinity. It is a figure which shows the area division of the prefectural border of three prefectures. It is a radio | wireless resource allocation figure of X prefecture. It is a radio | wireless resource allocation figure of Y prefecture. It is a radio | wireless resource allocation figure of X prefecture. It is a flowchart of an area determination process. It is explanatory drawing of a 1st radio | wireless resource allocation process. It is explanatory drawing of a 2nd radio | wireless resource allocation process. It is a figure which shows the change of the number of resources and the number of allocation changes with the increase in installation density.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[1. Outline of Embodiment]

(1) The method according to the embodiment is a radio resource allocation method in a target area, and at least a part of the first radio resource is transmitted to a first roadside device installed in a first area included in the target area. And allocating at least a part of a second radio resource different from the first radio resource to a second roadside device installed in a second area included in the target area. The first area is adjacent to a boundary of the target area. The second area is adjacent to the first area and is further away from the boundary than the first area. By making the radio resources different between the first area adjacent to the boundary and the second area far from the boundary, problems that occur in radio resource allocation near the boundary can be concentrated in the first area. Since the second area is far from the boundary and has different radio resources from the first area, it is possible to reduce problems that occur in radio resource allocation near the boundary. Note that the order in which the step of allocating at least a part of the first radio resource and the step of allocating at least a part of the second radio resource are performed in any order, and either may be performed first.

  Here, the target area is an area to which radio resources are allocated. The target area is, for example, a jurisdiction target area of a road management organization. The target area is, for example, a prefecture area, a municipal area, or the like. The target area may be an area where a plurality of prefectures are gathered or an area where a plurality of municipalities are gathered. If the target area is a prefecture, the boundary is the boundary of the prefecture. The target area does not need to correspond to the administrative division. The radio resource is, for example, time and frequency.

(2) It is preferable that the target area further includes a third area adjacent to the second area and further away from the boundary than the second area. Preferably, the method further includes allocating at least a part of radio resources including the first radio resource and the second radio resource to a third roadside device installed in the third area. Since the third area is away from the first area, the first radio resource allocated in the first area can be used in addition to the second radio resource allocated in the second area.

(3) The first radio resource is different from the fourth radio resource allocated to the fourth roadside device installed in the fourth area, and the fourth area is controlled by an organization different from the target area. It is preferably included in the non-target area and adjacent to the boundary. Since the first radio resource in the first area is different from the fourth radio resource outside the target area, adjustment with an organization having jurisdiction over the non-target area becomes unnecessary when radio resources are allocated in the first area.

(4) It is preferable that the second radio resource includes at least a part of the fourth radio resource. In this case, radio resources used outside the target area can also be used in the second area.

(5) The assignment of at least a part of the first radio resource to the first roadside device is performed based on a first algorithm for radio resource assignment, and the second roadside device has the second radio resource assigned to the first roadside device. The assignment of at least a part is preferably performed based on a second algorithm for radio resource assignment, which is different from the first algorithm. The first area near the boundary and the second area away from the boundary may have different area characteristics. Therefore, by assigning radio resources using different algorithms, appropriate allocation according to the area characteristics can be performed. It becomes possible.

(6) The first algorithm obtains an interference relationship between the plurality of first roadside machines based on the installation positions of the plurality of first roadside machines, and sends the first radio resource to the first roadside machine. The second algorithm is determined for each of a plurality of partial areas that divide an area where the second roadside unit is installed. It is preferably an algorithm that determines in advance which radio resources to be allocated. The first algorithm is suitable for an area where the roadside machine installation density is low, and the second algorithm is suitable for an area where the roadside machine installation density may be high. In the first area near the boundary, the roadside machine installation density is often low, so the first algorithm is suitable. The second area is preferable because the second area is likely to include an urban area, and a place with a high roadside machine installation density is likely to occur.

(7) The first radio resource is common to a fourth radio resource allocated to a fourth roadside device installed in the fourth area, and the fourth area is controlled by an organization different from the target area. Preferably, it is included in a non-target area and adjacent to the boundary. In this case, in the first area near the boundary, radio resource allocation is determined in cooperation with the non-target area.

(8) Allocating at least a part of the first radio resource to the first roadside device is considered to be a first area installed in the first area, considering the first area and the fourth area as one area. Allocating at least a part of the first radio resource to one roadside machine and a fourth roadside machine installed in the fourth area based on a first algorithm for radio resource allocation, It is preferable that the assignment of at least a part of the second radio resource to the two roadside device is performed based on a second algorithm for radio resource assignment, which is different from the first algorithm. In this case, radio resources are allocated together in the first area and the fourth area. In the second area, appropriate radio resource allocation can be performed using an algorithm different from that in the first area.

(9) A roadside machine system according to an embodiment is installed in a first area included in a target area, and includes a plurality of first roadside machines to which at least a part of a first radio resource is allocated, and the target area And a plurality of second roadside devices to which at least a part of second radio resources different from the first radio resources are allocated. The first area is adjacent to the boundary of the target area, and the second area is adjacent to the first area and is further away from the boundary than the first area.

(10) The method according to the embodiment is a radio resource allocation method, and allocates at least a part of the first radio resource to a first roadside device installed in a first area included in the first target area. Allocating at least a part of a second radio resource different from the first radio resource to a second roadside device installed in the second area included in the first target area, in the second target area Allocating at least a part of the fourth radio resource to a fourth roadside device installed in the fourth area included in the fifth area side device installed in the fifth area included in the second target area Allocating at least a part of a fifth radio resource different from the fourth radio resource. The first area is adjacent to a boundary of the first target area. The second area is adjacent to the first area and is further away from the boundary than the first area. The second target area is governed by an organization different from the first target area and is adjacent to the boundary. The fourth area is adjacent to the boundary. The fifth area is adjacent to the fourth area and is further away from the boundary than the fourth area.

(11) A computer program according to an embodiment causes a computer to function as a processing unit and a storage unit that stores area information indicating positions of the first area and the second area included in the target area. It is. The first area is adjacent to a boundary of the target area. The second area is adjacent to the first area and is further away from the boundary than the first area. When the processing unit acquires position information where the roadside machine is installed and determines that the installation position of the roadside machine indicated by the position information is included in the first area based on the area information, the roadside A machine is determined as a target of the first allocation process, and when it is determined that the installation position of the roadside machine indicated by the position information is included in the second area based on the area information, the roadside machine is 2. Processing including determining as an assignment processing target is performed. The first allocation process is a process of allocating at least a part of the first radio resource to a roadside device installed in the first area. The second allocation process is a process of allocating at least a part of a second radio resource different from the first radio resource to a roadside device installed in the second area.

(12) The method according to the embodiment is a radio resource allocation method, and allocates at least a part of the first radio resource to the first roadside device installed in the first area based on the first algorithm. Allocating at least a part of a second radio resource to a second roadside machine installed in a second area having a higher roadside machine installation density than the first area, based on a second algorithm, The first algorithm obtains an interference relationship between the plurality of first roadside devices based on the installation positions of the plurality of first roadside devices, and determines which of the first radio resources includes the first roadside device. The second algorithm is an algorithm for determining whether a radio resource is allocated, and the second algorithm is provided for each of a plurality of partial areas obtained by dividing an area where the second roadside device is installed. A Arigorizumu of what radio resources are allocated in the source is determined in advance. By assigning radio resources with different algorithms for each area, it is possible to appropriately assign according to the characteristics of the area.

(13) Preferably, the second area is adjacent to the first area, and the second radio resource is different from the first radio resource.

(14) The system according to the embodiment is a radio resource allocation system, and a process of allocating at least a part of the first radio resource to the first roadside device installed in the first area based on the first algorithm. And a process of allocating at least a part of the second radio resource to a second roadside device installed in a second area having a higher roadside device installation density than the first area, based on a second algorithm. A processing unit that executes processing, wherein the first algorithm obtains an interference relationship between the plurality of first roadside devices based on the installation positions of the plurality of first roadside devices, and , An algorithm for determining which radio resource included in the first radio resource is allocated, and the second algorithm classifies an area in which the second roadside unit is installed For each of the plurality of partial areas have, what radio resources are assigned included in the second radio resource is a Arigorizumu determined in advance.

(15) The computer program according to the embodiment is based on the second algorithm based on the first algorithm, the process of allocating at least a part of the first radio resource to the first roadside device installed in the first area. And a process for allocating at least a part of the second radio resource to a second roadside machine installed in a second area having a higher roadside machine installation density than the first area. It is a program. The first algorithm obtains an interference relationship between the plurality of first roadside devices based on the installation positions of the plurality of first roadside devices, and is included in the first radio resource in the first roadside device. It is an algorithm that determines which radio resources are allocated. The second algorithm is an algorithm in which which radio resource included in the second radio resource is allocated in advance for each of a plurality of partial areas obtained by dividing the area where the second roadside device is installed. .

[2. Details of Embodiment]
[2.1 Radio resource allocation system]
The plurality of radio resource allocation systems 10 shown in FIG. 1 are a radio allocation system 10 for X prefecture and a radio resource allocation system 10 for Y prefecture, respectively. The radio resource allocation system 10 includes a storage unit 11 and a processing unit 12. The radio resource allocation system is configured by a computer in which a computer program that performs processing for radio resource allocation is installed. The computer exhibits functions as the storage unit 11 and the processing unit 12 illustrated in FIG. 1 by executing the computer program.

  The storage unit 11 stores the computer program and area information 11a. The area information 11a is information for determining an area in the prefecture. The area information 11a will be described later. The processing unit 12 executes various processes 12a to 12c shown in FIG. The area determination process 12a is a process for determining which area (described later) the roadside machine belongs to. The first allocation process 12b and the second allocation process 12c are processes for allocating radio resources to roadside devices. These processes 12a to 12c will be described later.

[2.2 Radio resources and roadside system]
The radio resources to be allocated in the present embodiment are time slots SL1 to SL16 shown in FIG. Time slots SL1 to SL16 are assigned to ITS roadside units (base stations) 10A, 10B, 10D, and 10E. As shown in FIG. 2A, a plurality (16) of time slots SL1 to S16 are set within a control cycle having a predetermined time length (100 ms). The control cycle occurs repeatedly. In the control cycle, a period between each of the time slots SL1 to S16 is used for communication by a mobile station such as an in-vehicle device.

  Such time slots SL1 to SL16 are defined in the 700 MHz band intelligent transportation system (ARIB STD-T109). In the intelligent transportation system of this embodiment, time slots SL1 to SL16 shown in FIG. 2A are handled as usable radio resources. In the present embodiment, at least one of these 16 time slots SL1 to SL16 is assigned to each roadside device. The radio resource allocation to each roadside device may be performed in units of a part of time (sub time slot) in each time slot.

  FIG. 2B shows a plurality of roadside machines 10A, 10B, 10D, and 10E arranged in the vicinity of the prefectural border B between the X and Y prefectures. In FIG. 2B, the upper left side of the prefectural border B is the area of X prefecture (first target area), and the lower right side of the prefectural border B is the area of Y prefecture (second target area). In X prefecture, a roadside machine system 1A having a plurality of roadside machines 10A, 10B is provided, and in Y prefecture, a roadside machine system 1B having a plurality of roadside machines 10D, 10E is provided. Yes.

  In FIG.2 (b), each roadside machine 10A, 10B, 10D, 10E is installed in the intersection of a grid-like road, and is shown by the circle. The numbers in the circles indicate the slot numbers of the time slots SL1 to SL16, and are values in the range of 1 to 16. For example, if the number in the circle is “1”, it indicates that the first time slot SL1 is assigned to the roadside device indicated by the circle. If the number in the circle is “15”, it indicates that the 15th time slot SL15 is assigned to the roadside machine indicated by the circle. When a plurality of roadside devices to which the same time slot is assigned are close to each other, radio interference is likely to occur. Therefore, the distance between the plurality of roadside devices to which the same time slot is assigned should be sufficiently large. preferable.

  In the present embodiment, radio resource allocation for the roadside devices 10A and 10B in the X prefecture is performed on the responsibility of the first institution having jurisdiction over the X prefecture. Wireless resource allocation to the roadside devices 10D and 10E in Y prefecture is performed under the responsibility of the second organization having jurisdiction over Y prefecture. In other words, the first target area under the jurisdiction of the first institution is X prefecture, and the second target area under the jurisdiction of the second institution is Y prefecture. For the first institution, Y prefecture is not a jurisdiction but a non-target area, and for the second institution X prefecture is not a jurisdiction but a non-target area. The radio resource allocation in the X prefecture is performed by the radio resource allocation system 10 in the X prefecture, and the radio resource allocation in the Y prefecture is performed by the radio resource allocation system 10 in the Y prefecture.

  The first engine and the second engine are separate engines. Each institution manages and operates an intelligent road traffic system according to the 700 MHz band intelligent road traffic system (ARIB-STD T109) within the target area under its jurisdiction. That is, the first engine basically independently determines the time slot assignment for the plurality of roadside machines 10A and 10B constituting the roadside machine system 1A in the X prefecture. The second engine basically independently determines time slot assignments for the plurality of roadside machines 10D and 10E that constitute the roadside machine system 1B in Y prefecture.

  When each of the first engine and the second engine decides the allocation of the time slots SL1 to SL16 in consideration of only within its own prefecture, the X-prefecture roadside machine 10A and the Y-prefecture roadside machine 10D near the prefectural border The same time slot may be assigned. In this case, radio interference occurs from X prefecture to Y prefecture, and mutual interference occurs from Y prefecture to radio interference in X prefecture.

  Therefore, in this embodiment, radio resource allocation as shown in FIG. 2 is performed. In FIG. 2, X prefecture and Y prefecture are each divided into two areas. That is, X prefecture is divided into a mutual interference area (first area) 101 adjacent to the prefectural border B with Y prefecture, and an independent area (second area) 102 inside the mutual interference area 101. The roadside machine 10A installed in the mutual interference area 101 is called a first roadside machine, and the roadside machine 10B installed in the independent area 102 is called a second roadside machine. Y prefecture is divided into a mutual interference area (fourth area) 104 adjacent to the prefectural border B with X prefecture, and an independent area (fifth area) 105 inside the mutual interference area 104. The roadside machine 10D installed in the mutual interference area 104 is called a fourth roadside machine, and the roadside machine 10E installed in the independent area 105 is called a fifth roadside machine.

  Most of the prefecture areas in each prefecture are independent areas 102 and 105, and areas near the prefectural border are mutual interference areas 101 and 104. Since the independent areas 102 and 105 are most areas in the prefecture, they often include urban areas and often have places where the roadside machine installation density is relatively high. On the other hand, since the mutual interference area is near the prefectural border B, it is often in the suburbs and the roadside machine installation density is relatively low.

  The mutual interference areas 101 and 104 are areas in which the roadside devices 10A and 10D installed therein may interfere with roadside devices in other prefectures and may receive interference from roadside devices in other prefectures. The mutual interference areas 101 and 104 are narrow areas along the prefectural border B, respectively. The area widths W1 and W2 of the mutual interference areas 101 and 104 are about 1.5 km to 2 km. The area widths W1 and W2 are intervals from the boundaries 111 and 121 between the mutual interference areas 101 and 104 and the independent areas 102 and 105 to the prefectural border B, respectively.

  On the other hand, the independent areas 102 and 105 are areas that are unlikely to interfere with roadside machines in other prefectures and are less likely to receive interference from roadside machines in other prefectures. The independent areas 102 and 105 are adjacent to the mutual interference areas 101 and 104, but are separated from the prefectural border B more than the mutual interference areas 101 and 104, so that mutual interference does not occur or mutual interference is weak.

  In FIG. 2, among the 16 time slots SL1 to SL16, the radio resources (time slots) that can be allocated to the roadside device are divided in the mutual interference areas 101 and 104 and the independent areas 102 and 105. As shown in FIG. 2A, of the 16 time slots SL1 to SL16, ten time slots from the first time slot SL1 to the tenth time slot SL10 are roadside units 10B in the independent areas 102 and 105. , 10E. The remaining six time slots from the eleventh time slot SL11 to the sixteenth time slot SL16 are for allocation of the mutual interference areas 101 and 104 to the roadside devices 10A and 10D.

  In FIG. 2, the independent areas 102 and 105 have more assignable radio resources than the mutual interference areas 101 and 104. The independent areas 102 and 105 are very large compared to the mutual interference areas 101 and 104, and it is assumed that the installation density of roadside units will be high. Therefore, since there are many assignable radio resources, radio resource allocation is easy. Become.

  Here, the time slots SL11 to SL16 allocated to the first roadside device 10A in the mutual interference area (first area) 101 of the X prefecture are referred to as first radio resources, and the first slots in the independent area (second area) 102 of the X prefecture. The time slots SL1 to SL10 assigned to the two roadside device 10B are referred to as second radio resources. Also, the time slots SL11 to SL16 allocated to the fourth roadside device 10D in the mutual interference area (fourth area) 104 in Y prefecture are also referred to as fourth radio resources, and the fifth in the independent area (fifth area) 105 in Y prefecture. The time slots SL1 to SL10 assigned to the roadside device 10E are also referred to as fifth radio resources. Here, as shown in FIG. 2, the first radio resource and the fourth radio resource are common, and the second radio resource and the fifth radio resource are also common.

  Since the independent areas 102 and 105 are separated from the prefectural border B, the radio resource allocation system 10 of each prefecture does not consider other prefectures for the roadside devices 10B and 10E in the independent areas 102 and 105. Independently, radio resource allocation can be determined. That is, the system 10 in the X prefecture allocates at least a part of the slots SL1 to SL10 that are the second radio resources to the plurality of roadside devices 10B in the independent area 102 without considering the allocation in the Y prefecture. . In addition, the system 10 in Y prefecture allocates at least a part of the slots SL1 to SL10, which are the fifth radio resources, to the plurality of roadside devices 10E in the independent area 105 without considering the allocation in the X prefecture. . The wireless resource allocation process is performed when a roadside device is newly installed. When a new roadside unit is installed, the radio resource allocation process may only determine the radio resource allocated to the newly installed roadside unit, but with a change of the radio resource allocated to the existing roadside unit. Also good.

  Regarding the mutual interference areas 101 and 104, each prefecture is not determined independently, but radio resources are allocated to the roadside devices 10A and 10D in the mutual interference areas 101 and 104 while coordinating with the institutions of the neighboring prefectures. Can be determined. The radio resources for allocation to the mutual interference areas 101 and 104 (time slots SL11 to SL16) are different from the radio resources for allocation to the independent areas 102 and 105 (time slots SL1 to SL10). , 104 can be made without considering the assignment in the independent areas 102, 105 of the own prefecture and other prefectures.

  Here, regarding the radio resource allocation of the mutual interference areas 101 and 104 in the X and Y prefectures, the two mutual interference areas 101 and 104 are regarded as one area. That is, a plurality of mutual interference areas existing via the prefectural border B are regarded as one area. In the radio resource allocation processing in the plurality of mutual interference areas 101 and 104 regarded as one area, the first radio resource for the mutual interference area (= first) is set so that mutual interference does not occur in each of the roadside devices 10A and 10D. By determining the allocation within the range of (4 radio resources), it is possible to prevent the occurrence of mutual interference near the prefectural border B. The mutual interference area may be a small part of the prefecture area and the roadside equipment installation density is assumed to be low, so even if the mutual interference area across multiple prefectures is considered as one area, each prefecture's organization is unique. Can be kept high.

[2.3 Considerations on radio resource amount and radio resource allocation change frequency]
FIG. 3 shows how the radio resource amount and the radio resource allocation change frequency (change rate) change as the roadside device installation density increases. In addition, the roadside machine installation density increases because new roadside machines increase as time elapses. FIG. 3 (a) is a case where X prefecture and Y prefecture each determine resource allocation in a self-centered manner, and FIG. 3 (b) is a case where only X prefecture determines a resource allocation with compromise, FIG. 3C shows a case where both prefectures make a compromise to determine resource allocation.

  In the self-centered decision, each prefecture decides allocation of the time slots SL1 to SL16 completely independently, considering only within the prefecture. In this case, the uniqueness of each prefecture will increase, but since the allocated resources will not be changed in other prefectures for other prefectures, the number of roadside machines will increase as shown in FIG. As the roadside machine installation density increases, the number of required radio resources increases in both X and Y prefectures. This causes a shortage of radio resources. However, in the self-centered decision, it is not necessary to change the already allocated resources in other prefectures for other prefectures, so the increase in resource change rate will be moderate.

  Depending on the way of allocating resources in Y prefecture, when only X prefecture makes a compromise and changes the already allocated resources in X prefecture, Y prefecture can determine the allocation considering only within its own prefecture. Therefore, as shown in FIG. 3B, the roadside machine installation density in Y prefecture is moderate. On the other hand, in the X prefecture, when the roadside machine installation density increases to some extent, the synergistic effect with the increase in the roadside machine installation density in the Y prefecture increases the need to change the already allocated resources in the X prefecture. As a result, the resource change rate increases rapidly, and the adjustment load such as allocation change and operation check after change increases. In X prefecture, the amount of resources necessary to perform resource allocation that does not cause interference tends to increase.

  Thus, self-centered decisions and compromises in one prefecture tend to increase the amount of radio resources and the frequency of changing radio resource allocation. On the other hand, as shown in FIG. 3 (c), when both prefectures compromise and decide resource allocation, it is possible to prevent the radio resource amount and the resource change rate from greatly increasing, The degree of increase and increase in resource change rate can be kept within an appropriate range in each prefecture.

  Since the radio resource allocation shown in FIG. 2 is a compromise between the mutual interference areas 101 and 104, the increase of the radio resource amount and the increase of the resource change rate can be suppressed to an appropriate range in each prefecture. . In addition, since the independent areas 101 and 104 can determine radio resource allocation in a self-centered manner, the uniqueness of each prefecture can be maintained.

[2.4 Allocation of radio resources for mutual interference area by prefecture]
FIG. 4 shows a resource allocation method when time slots SL11 to SL16 for allocation to the mutual interference areas 101 and 104 are allocated in advance to each prefecture. The first time slot SL1 to the tenth time slot SL10 are for allocation to the roadside devices 10B and 10E in the independent areas 102 and 105 as in FIG. On the other hand, the eleventh time slot SL11 to the sixteenth time slot SL16 are for allocation to the mutual interference areas 101 and 104, but the eleventh time slot SL11 to the sixteenth time slot SL16 are divided in advance for each prefecture. Yes. That is, the roadside units 10A and 10D in the mutual interference areas 101 and 104 of the prefectures use different time slots.

  For example, an eleventh time slot SL11 and a twelfth time slot SL12 are reserved for allocation to the mutual interference area 101 in X prefecture, and a thirteenth time slot SL13 and a thirteenth time allocation for allocation to the mutual interference area 104 in Y prefecture. It is assumed that 14 time slots SL14 are secured. In this case, the number of time slots that can be used in the mutual interference areas 101 and 104 of each prefecture is reduced, but the time slots used in the mutual interference areas 101 and 104 of each prefecture are different. 10 can independently perform radio resource allocation in the mutual interference areas 101 and 104 as well.

  Here, as shown in FIGS. 4A and 4B, the time slots SL11 and SL12 assigned to the mutual interference area (first area) 101 of X prefecture are referred to as first radio resources, and the independent area ( The time slot allocated to (second area) 102 is referred to as a second radio resource. In addition to the time slots SL1 to SL10 for the independent areas, the second radio resource includes time slots SL13 to SL13 that are not used in the mutual interference area 101 in the X prefecture (own prefecture) among the time slots SL11 to SL16 for the mutual interference area. SL16 is also included. In the independent area 102 of X prefecture, even if the time slot used in the mutual interference area 104 of Y prefecture (other prefecture) is not used in the mutual interference area 101 of X prefecture (own prefecture), mutual interference occurs. Absent. Therefore, in the independent area 102 of X prefecture, the time slots SL13 to SL16 can be used as the second radio resources, and the amount of resources that can be used increases.

  Also, the time slots SL13 and SL14 assigned to the mutual interference area (fourth area) 104 in Y prefecture are referred to as fourth radio resources, and the time slots assigned to the independent area (fifth area) 105 in Y prefecture are designated as the fifth radio. It is called a resource. In addition to the time slots SL1 to SL10 for independent areas, among the time slots SL11 to SL16 for mutual interference areas, the fifth radio resource includes time slots SL11, which are not used in the mutual interference area 104 of Y prefecture (own prefecture). SL12, SL15, and SL16 are also included. In the independent area 105 of Y prefecture, even if the time slot used in the mutual interference area 101 of X prefecture (other prefecture) is not used in the mutual interference area 104 of Y prefecture (own prefecture), mutual interference occurs. Absent. Therefore, in the independent area 105 of Y prefecture, the time slots SL11, SL12, SL15, and SL16 can be used as the fifth radio resource, and the amount of resources that can be used increases.

  As shown in FIGS. 4A and 4B, the second radio resource used in the independent area 102 in the X prefecture and the fifth radio resource used in the independent area 105 in the Y prefecture are partially (SL1 to SL10). ). The first radio resources SL11 and SL12 used in the mutual interference area 101 of the X prefecture are different from the fourth radio resources SL13 and 14 used in the mutual interference area 104 of the Y prefecture. The second radio resources SL1 to SL10 and SL13 to SL16 used in the independent area 102 of the X prefecture include fourth radio resources SL13 and SL14. The fifth radio resources SL1 to SL10, SL11, SL12, SL15, and SL16 used in the independent area 105 of Y prefecture include the first radio resources SL11 and SL12.

  Among the second radio resources SL1 to SL10 and SL13 to SL16 used in the independent area 102 of X prefecture, the time slots SL1 to SL10 that are originally for the independent area are set as basic radio resources for allocation in the independent area, Mainly, the time slots SL13 to SL16 for the mutual interference area can be used as backup radio resources. For example, in the independent area 102 of X prefecture, in the normal radio resource allocation, only the basic radio resources SL1 to SL10 are used. On the other hand, the roadside unit is densely installed, and there is a specific interference relationship. By assigning spare radio resources SL13 to SL16 to the machine, it is possible to flexibly implement resource assignment in an area where roadside machines are densely installed. The same allocation method can be performed in the independent area 105 of Y prefecture.

[2.5 Wireless resource allocation in independent area center]
FIG. 5 shows a radio resource allocation method in the case where the independent area (area excluding the mutual interference area) of each prefecture is divided into the peripheral part 102 and the central part 103. In FIG. 5, the independent area 1020 in X prefecture is divided into a peripheral part 102 and a central part 103. Hereinafter, the peripheral portion 102 of the independent area 1020 is referred to as a second area, and the central portion 103 of the independent area 1020 is referred to as a third area. The third area 103 is adjacent to the second area 102 and is farther from the prefectural border B than the first area which is a mutual interference area.

  Therefore, in FIG. 5, X prefecture has a mutual interference area (first area) 101 adjacent to the prefectural border B, an independent area peripheral part (second area) 102 adjacent to the mutual interference area 101, and an independent area peripheral part 102. And an independent area central portion (third area) 103 adjacent to each other. The roadside machine 10A installed in the mutual interference area 101 is called a first roadside machine, and the roadside machine 10B installed in the independent area peripheral part 102 is called a second roadside machine, installed in the independent area center 103. The roadside machine 10C is referred to as a third roadside machine.

  Most of the area in the prefecture of X prefecture is the independent area center 103. The independent area peripheral portion 102 of X prefecture is an area where there is a risk of mutual interference with the mutual interference area 101 of X prefecture but no mutual interference with Y prefecture. The independent area central part 103 of X prefecture is an area where no mutual interference occurs with the mutual interference area 101 of X prefecture. In FIG. 5, the central part of the independent area of Y prefecture is not shown, but Y prefecture is similarly divided into three areas.

  The independent area peripheral portion 102 is a narrow area along the boundary 111 between the mutual interference area 101 and the independent area. The area width W1 of the independent area peripheral portion 102 is about 1.5 km to 2 km. Note that the area width W1 of the independent area peripheral portion 102 and the distance from the boundary 111 between the mutual interference area 101 and the independent area to the boundary 112 between the independent area peripheral portion 102 and the independent area central portion 103 are shown.

  In the independent area peripheral portion 102 in FIG. 5, the second radio resource can be used as in the independent area 102 in FIG. In the independent area center 103, not only the second radio resource but also the first radio resource for allocation to the mutual interference area 101 can be used. That is, in the independent area center 103, all the time slots SL1 to SL16 can be used. Since the independent area center part 103 does not cause mutual interference with the mutual interference area 101, many wireless resources including the wireless resources used in the mutual interference area 101 can be used.

  The radio resource used in the independent area center 103 can include a radio resource for the mutual interference area 101 in its own prefecture (X prefecture), and a radio resource for the mutual interference area 102 in another prefecture (Y prefecture). Can also be included.

  Among the wireless resources SL1 to SL16 used in the independent area center 103 of X prefecture, the wireless resources SL1 to SL10, SL13, and SL16 that can also be used in the independent area peripheral section 102 are allocated for allocation in the independent area center 103. As basic radio resources, radio resources SL11 and SL12 that can be used in the mutual interference area 101 can be used as backup radio resources. For example, in the independent area center 103 of X prefecture, in the normal radio resource allocation, only the basic radio resources SL1 to SL10 and SL13 to SL16 are used in the same manner as the independent area peripheral part 102 of X prefecture. Is allocated, and reserve radio resources SL11 and SL12 are allocated to the roadside devices in the area where the specific interference relationship occurs, so that resource allocation in the area where the roadside devices are closely installed is flexibly performed. it can. The same allocation method can be performed in the independent area 1050 of Y prefecture.

  FIG. 6 shows a state in which each of the X prefecture, the Y prefecture, and the Z prefecture adjacent to each other is divided into the above-described three areas. In FIG. 6, the prefecture X is in contact with the prefecture Y through the prefectural border B1, and is in contact with the prefecture Z through the prefectural border B2. The mutual interference area 101 of X prefecture is provided along the prefectural borders B1 and B2. An independent area 1020 is provided inside the mutual interference area 101 of X prefecture. The independent area 1020 includes an independent area peripheral portion 102 adjacent to the mutual interference area 101 and an independent area central portion 103 provided inside the independent area peripheral portion 102.

  Y prefecture is in contact with X prefecture through the prefectural border B1, and is in contact with Z prefecture through the prefectural border B3. The mutual interference area 104 of Y prefecture is provided along the prefectural borders B1 and B3. An independent area 1050 is provided inside the mutual interference area 104 of Y prefecture. The independent area 1050 includes an independent area peripheral portion 105 adjacent to the mutual interference area 104 and an independent area central portion (sixth area) 106 provided inside the independent area peripheral portion 106. The roadside machine installed in the independent area peripheral part 105 is called a fifth roadside machine, and the roadside machine installed in the independent area center part 106 is called a sixth roadside machine.

  The mutual interference area 107 of Z prefecture is provided along the prefectural borders B2 and B3. An independent area 1080 is provided inside the mutual interference area 107 of Z prefecture. The independent area 1080 includes an independent area peripheral portion 108 adjacent to the mutual interference area 107 and an independent area central portion 109 provided inside the independent area peripheral portion 108. The roadside machine installed in the mutual interference area 107 is called the seventh roadside machine, and the roadside machine installed in the independent area peripheral part 108 is called the eighth roadside machine, and is installed in the independent area center 109. This roadside machine is called the ninth roadside machine.

  FIG. 7 shows time slots that can be assigned to roadside devices in the mutual interference area 101, the independent area peripheral part 102, and the independent area center part 103 of X prefecture shown in FIG. In the mutual interference area 101, radio resources that can be allocated to the first roadside device 10A are time slots SL11 and SL12. In the mutual interference area 101, other time slots cannot be used. In the independent area peripheral portion 102, the radio resources that can be allocated to the second roadside device 10B are used in the mutual interference areas 104 and 107 in other prefectures in addition to the time slots SL1 to SL10 that can be originally used in the independent area 1020. At least a part of the time slots SL13 to SL16. That is, in the independent area peripheral portion 102, the time slots SL11 and SL12 used in the mutual interference area 101 cannot be used. On the other hand, in the independent area central portion 103, at least a part of the time slots SL11 and SL12 that cannot be used in the independent area peripheral portion 102 can be used. Here, all the time slots SL1 to SL16 are used for the third roadside device 10C. Assignable.

  FIG. 8 shows time slots that can be allocated to roadside devices in the mutual interference area 104, the independent area peripheral part 105, and the independent area center part 106 of Y prefecture shown in FIG. In the mutual interference area 104, radio resources that can be allocated to the fourth roadside device 10D are time slots SL13 and SL14. In the mutual interference area 104, other time slots cannot be used. In the independent area peripheral part 105, the radio resources that can be allocated to the fifth roadside device 10E are used in the mutual interference areas 101 and 107 in other prefectures in addition to the time slots SL1 to SL10 that can be essentially used in the independent area 1050. Time slots SL11, SL12, SL15, and SL16. That is, in the independent area peripheral portion 105, the time slots SL13 and SL14 used in the mutual interference area 104 cannot be used. On the other hand, in the independent area central part 106, at least a part of the time slots SL13 and SL14 that cannot be used in the independent area peripheral part 105 can be used. Here, all the time slots SL1 to SL16 are assigned to the sixth roadside device. Is possible.

  FIG. 9 shows time slots that can be assigned to roadside devices in the mutual interference area 107, the independent area peripheral portion 108, and the independent area center portion 109 in the Z prefecture shown in FIG. In the mutual interference area 107, radio resources that can be allocated to the seventh roadside device are time slots SL15 and SL16. In the mutual interference area 107, other time slots cannot be used. In the independent area peripheral portion 108, the radio resources that can be allocated to the sixth roadside machine are used in the mutual interference areas 101 and 104 in other prefectures in addition to the time slots SL1 to SL10 that can be originally used in the independent area 1080. It is at least a part of the time slots SL11 to SL14. That is, in the independent area peripheral portion 108, the time slots SL15 and SL16 used in the mutual interference area 107 cannot be used. On the other hand, in the independent area central portion 109, at least a part of the time slots SL15 and SL16 that cannot be used in the independent area peripheral portion 108 can be used. Here, all the time slots SL1 to SL16 are assigned to the ninth roadside device. Is possible.

  As shown in FIGS. 7 to 9, since the radio resources used in the mutual interference areas 101, 104, and 107 can be used in the independent area central portions 103, 106, and 109, many radio resources can be secured.

[2.6 Processing by Radio Resource Allocation System]
Radio resource allocation is performed by separate processing in the mutual interference area and the independent area. Here, the process for allocating radio resources to roadside devices in the mutual interference area is referred to as a first allocation process 12b, and the process for allocating radio resources to roadside machines in an independent area is referred to as a second allocation process 12c. (See FIG. 1). Each of the processes 12b and 12c may perform radio resource allocation using a common algorithm. However, in the present embodiment, radio resource allocation is performed using different algorithms in view of differences in area characteristics.

  Since the allocation processes 12b and 12c are different between the mutual interference area and the independent area, the radio resource allocation system 10 of each prefecture determines whether the roadside equipment installed in the prefecture is located within the mutual interference area. It is necessary to distinguish between the two. In addition, when the independent area is divided into the peripheral part and the central part, the available radio resources differ between the peripheral part and the central part, so whether the roadside device in the independent area is located in the peripheral part or not. It is necessary to distinguish between the two.

  FIG. 10 shows an area determination process 12a (see FIG. 1) for determining which area the roadside machine belongs to. The area determination process 12a is performed by the radio resource allocation system 10 for each prefecture. In this area determination process 12a, the position of the roadside machine (position within the prefecture) is acquired as step S11. The position may be expressed as a position in a geographic coordinate system, or may be a position on a road map. The acquisition of the position may be performed by user input, for example, or may be acquired from the storage unit 11a or acquired from communication with another system.

  The position information acquired in step S11 is compared with the area information 11a stored in the storage unit 11 in step S12. The area information 11a is information obtained by dividing the prefecture area into mutual interference areas (first areas) 101, 104, 107, independent area peripheral parts 102, 105, 108, and independent area central parts 103, 106, 109. When the independent area is not divided into the peripheral part and the central part, the area information 11a is information obtained by dividing the prefecture area into the mutual interference areas 101 and 104 and the independent areas 102 and 105.

  Based on the comparison between the position information and the area information 11a, in step S13, it is determined to which area the position of the roadside machine indicated by the position information belongs. If it is determined in step S13 that the position of the roadside device is within the mutual interference area, which is the first area, the roadside device is determined as a target of the first assignment process 12b (step S14). For example, in the case of X prefecture, since the radio resources that can be used in the mutual interference area 101 are the time slots SL11 and SL12 that are the first radio resources, the time slot SL11 is assigned to the roadside device by the first allocation process 12b. , SL12 is assigned.

  If it is determined in step S13 that the position of the roadside device is within the peripheral area of the independent area that is the second area, the roadside device is determined as a target of the second allocation process 12c (step S15). ). For example, in the case of X prefecture, the radio resources that can be used in the independent area peripheral portion 102 are the time slots SL1 to SL10 and SL13 to SL16 that are the second radio resources. Thus, one of the time slots SL1 to SL10 and SL13 to SL16 is assigned.

  Furthermore, when it is determined in step S13 that the position of the roadside device is within the central area of the independent area that is the third area, the roadside device is determined as a target of the second assignment process 12c (step S16). ). For example, in the case of X prefecture, the radio resources that can be used in the independent area central portion 103 are the time slots SL1 to SL16 that are both the first radio resource and the second radio resource. Any one of the time slots SL1 to SL16 is assigned by the assignment process 12c.

  If there are a plurality of roadside devices that require radio resource allocation, the area determination process 12a is performed for all the plurality of roadside devices.

  The first allocation process 12b is performed on one or more first roadside devices determined in the mutual interference area, which is the first area, in the determination process 12a. The first allocation process 12b is performed based on a first algorithm for radio resource allocation. The first algorithm of the present embodiment is an algorithm for determining radio resource allocation by obtaining an interference relationship between a plurality of roadside devices based on a position where the roadside device is actually installed. As such a 1st algorithm, there exists a Station-based Greddy (SG) algorithm (refer nonpatent literature 1, 2), for example.

  The SG algorithm calculates mutual interference (giving interference and interference) for each roadside unit (Station) based on the installation position of the roadside unit, and uses the same resource (time) for a plurality of roadside units without mutual interference. Slot). In the SG algorithm, radio resources are allocated from a densely installed roadside device. By deciding radio resource allocation from a dense area with little room for resource selection, the number of required resources can be reduced compared to deciding radio resource allocation from an area where roadside equipment is sparse.

  FIG. 11 shows how to determine radio resource allocation based on the SG algorithm. In FIG. 11, A1 to A26 are roadside machines, respectively, and are installed at intersections. First, as shown to Fig.11 (a), roadside machine A15 with the highest installation density is selected as object roadside machine, and radio | wireless resources (for example, time slot SL11) are allocated. At this time, the roadside machine A15 is the first roadside machine to which the time slot SL11 is assigned. Subsequently, a roadside device to which the same radio resource as the roadside device A15 is assigned is searched. Specifically, the interference relationship between the target roadside machine A15 and the other roadside machines A1 to A14, A16 to A26 is calculated, and the target roadside machine A15 is the first non-interfering roadside machine ( A roadside machine that does not receive interference from the target roadside machine A15 is extracted (see FIG. 11A). For example, if the radio wave interference given from the target roadside machine A15 into the communication area E of the roadside machine A9 is calculated and the radio wave interference is weak, the roadside machine A9 is extracted as the first non-interfering roadside machine.

  Subsequently, based on the calculation result of the interference relationship, among the first non-interfering roadside machines shown in FIG. 11A, a second non-interfering roadside machine (target roadside machine that does not serve as an interference source to the target roadside machine A15). A roadside machine that does not interfere with A is extracted (see FIG. 11B). For example, among the first non-interfering roadside machines, the roadside machine A4 and the roadside machine A9 calculate the radio wave interference given to the communication area E of the target roadside machine A15, and if the radio wave interference is strong, the roadside machine A4 and the roadside machine A9 Is not extracted as the second non-interfering roadside machine. In FIG.11 (b), roadside machine A1, A5, A6, A8, A21, A22, A26 is extracted as a 2nd non-interference roadside machine.

  The second non-roadside interference roadside device can be assigned the same radio resource as the target roadside device A15 to which radio resources have already been assigned. Among these, the same radio resource (for example, time slot SL11) as the target roadside machine A15 is allocated to the roadside machine having the shortest distance from the target roadside machine A15 or the highest density of the roadside machine. Here, for example, the same radio resource as that of the target roadside machine A15 is allocated to the roadside machine A22. Subsequently, in the second non-interfering roadside machine, when the roadside machine A8 has the shortest distance from the target roadside machine A15 next to the roadside machine A22 or the roadside machine having the highest density is the roadside machine A8. If the roadside machine A8 has no mutual interference relationship with the roadside machine A22 in addition to the roadside machine A15 to which radio resources have already been assigned, the same radio resource as the target roadside machine A15 is also assigned to the roadside machine A8. On the other hand, if there is a mutual interference relationship, an attempt is made to allocate different radio resources to the roadside device A15 and the roadside device A22. At this time, if there is no other roadside device to which the different radio resource (for example, time slot SL10) is assigned, the same processing as that of the roadside device A15 is performed. If there is another roadside device to which the different radio resource is assigned, the same processing as that performed when the roadside device A15 is the time slot SL11 is performed. By repeating this for a plurality of second non-interfering roadside devices in the time slot SL11, roadside devices A6, A8, A22, A26 to which the same radio resource (time slot SL11) as the target roadside device A15 can be assigned are determined. (Refer FIG.11 (c)).

  When the above processing is completed, the processing in FIGS. 11A to 11C is repeated with the roadside machine (for example, roadside machine A10) in the vicinity of the target roadside machine A15 as the next target roadside machine. Thereby, it is determined which radio resource included in the first radio resources (SL11, SL12) is allocated to each roadside device installed in the area (mutual interference area) targeted by the first allocation process.

  As shown in FIGS. 4 and 5, when the radio resources used in the mutual interference areas 101 and 104 of each prefecture are different, the first allocation process 12b is performed independently by the radio resource allocation system 10 of each prefecture. Can be executed. Adjustment necessary for a plurality of prefectures is only adjustment of which radio resource each prefecture uses in the mutual interference areas 101 and 104 before allocation. On the other hand, as shown in FIG. 2, when using the common radio resources SL11 to SL16 in the adjacent mutual interference areas 101 and 104, the radio resource allocation system 10 of each prefecture cooperates with the first allocation process 12b. Will be executed. Alternatively, the radio resource allocation system 10 of one prefecture (for example, X prefecture) regards the plurality of mutual interference areas 101 and 104 including the mutual interference area 104 of Y prefecture as one mutual interference area, and performs the first allocation process. 12b may be executed to determine radio resource allocation to the roadside devices 10A and 10D in the plurality of mutual interference areas 101 and 104.

  The second allocation process 12c is determined in the determination process 12b as the second roadside machine determined to be in the peripheral area of the independent area that is the second area and the third roadside determined to be the central area of the independent area that is the third area. It is performed for both machines. However, any time slot included in the first radio resource and the second radio resource can be assigned to the third roadside machine in the independent area center, but the second roadside machine in the independent area peripheral part can be assigned to the second roadside machine. Only radio resources can be allocated, and the first radio resource used in the mutual interference area of the prefecture is not allocated.

  The second allocation process 12c is performed based on the second algorithm for radio resource allocation. The second algorithm of the present embodiment uses cell allocation information in which which radio resource is allocated for each of a plurality of partial areas (cells) that divide an area (independent area) where roadside devices are installed. Thus, it is an algorithm that determines which radio resource is allocated to the roadside device. As an algorithm for determining such cell allocation information, for example, refer to the Vector-based cell Cover (VC) algorithm (Non-Patent Documents 1 and 2).

  In the VC algorithm, as shown in FIG. 12A, an area (for example, an independent area) where a roadside unit is installed is divided into mesh-shaped partial areas (cells) of a certain size. In FIG. 12A, the area where the roadside machine is installed is an area having a grid road R, and the intersection where the roadside machine is installed is indicated by a black circle. The size of the cell is preferably such that one roadside machine can enter one cell.

  In the VC algorithm, not the actual installation position of the roadside unit, but the interference relationship between cells is calculated, and for a specific cell, a cell of an appropriate size with a short interference distance and regularity between cells is searched. The same radio resource (time slot) as that of the specific cell is allocated to a cell that is a distance away from each other (non-interference vector). For example, when the cell C1 and the cell C2 shown in FIG. 12A are in an interference relationship, different radio resources are allocated to the cell C1 and the cell C2. Moreover, when the cell C1 and the cell C3 are non-interfering, the same radio resource can be allocated to the cell C1 and the cell C3. FIG. 12B shows cell allocation information in which radio resources (time slots) are allocated for each cell. In FIG. 12B, the numbers in the cells indicate the time slot numbers (values 1 to 16), the cell C2 is assigned a fifth time slot SL5 different from the cell C1, and the cell C3 is assigned to the cell C3. , The same third time slot SL6 as cell 1 is allocated. In FIG. 12B, only one time slot is assigned to one cell, but a plurality of time slots can be assigned to one cell.

  In addition, any time slot included in the first radio resource and the second radio resource can be allocated to the cell in the independent area center, but only the second radio resource can be allocated to the cell in the peripheral area of the independent area. And the first radio resource is not allocated.

  In the second allocation process 12c, a cell corresponding to the position of the roadside device is extracted from the cell allocation information based on the location information of the roadside device in the independent area (second area or third area), and the extracted cell is The allocated radio resource (time slot) is determined as a radio resource allocated to the roadside device. In addition, when a plurality of time slots are assigned to one cell, it is possible to cope with a case where a plurality of roadside devices are installed in one cell.

  FIG. 13 shows a comparison between the SG algorithm and the VC algorithm. FIG. 13 shows how the number of radio resources (amount) and the number of resource allocation changes (resource change rate) change with an increase in roadside equipment installation density in each algorithm. In FIG. 13, “SG” is a case in which, when a roadside device is newly established, the allocation of radio resources of the newly installed roadside device is determined while allowing the change of the allocated radio resources of the existing roadside device in the SG algorithm. Show. On the other hand, “SG ′” in FIG. 13 indicates a case in which, in the SG algorithm, a radio resource allocated to an existing roadside device is not allowed to be changed, and a radio resource allocated to a new roadside device is determined.

  As shown in FIG. 13, in SG, if there is a new roadside device, resource reassignment is performed including the existing roadside device. Therefore, the required number of resources is relatively small, but the number of allocation changes increases, and the allocation changes. Adjustment load such as operation check after change is large. On the other hand, VC performs resource allocation for each cell in advance, so that the number of resources increases even when the installation density (number of installations) is small, but the resource change rate decreases. The adjustment load is small. SG 'does not change the resources of the existing roadside machine, so the number of resource changes is smaller than SG, but unlike VC, it cannot be assigned systematically, so the number of roadside machines increases as roadside machines are installed. Then, the number of necessary resources tends to increase.

  Thus, the number of required resources and the number of allocation changes (adjustment load) differ depending on the algorithm. Therefore, by changing the algorithm according to the characteristics of the area where resource allocation is performed, it is possible to allocate radio resources appropriately according to the characteristics of the area. For example, SG and SG ′ increase the number of allocation changes or increase the number of resources as the installation density increases. This algorithm is suitable for areas with low installation density. That is, the SG algorithm is suitable when it is an area near the prefectural border, such as a mutual interference area (first area), and the installation density of roadside devices is low.

  On the other hand, VC is an algorithm suitable for an area where the roadside machine installation density may increase because the number of allocation changes does not increase even if the installation density increases. In other words, the VC algorithm is suitable when the urban area is often included as in the independent area (second area) and the roadside machine has a high installation density.

  Even in the mutual interference area (area near the prefectural border), the VC algorithm can be used when the installation density is high, and even in the independent area, the SG algorithm can be used when the installation density is low.

[3. Addendum]
The above-described embodiments and modifications should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1A Roadside machine system 1B Roadside machine system 10 Radio resource allocation system 10A Roadside machine 10B Roadside machine 10C Roadside machine 10D Roadside machine 10E Roadside machine 11 Storage unit 11a Area information 12 Processing unit 12a Area determination process 12b First allocation process 12c Second allocation Process 101 1st area 102 2nd area 103 3rd area 104 4th area 105 6th area 107 7th area 108 8th area B Prefectural border

Claims (8)

A wireless resource allocation method in a target area by a computer ,
The computer allocates at least a part of a first radio resource to a first roadside device installed in a first area included in the target area;
The computer allocates at least part of a second radio resource different from the first radio resource to a second roadside device installed in a second area included in the target area;
Including
The first area is adjacent to the boundary of the target area,
The second area is adjacent to the first area and is further away from the boundary than the first area ;
The first radio resource is common to a fourth radio resource allocated to a fourth roadside device installed in a fourth area,
The fourth area is a radio resource allocation method that is included in a non-target area managed by an organization different from the target area and is adjacent to the boundary . The target area further includes a third area adjacent to the second area and farther from the boundary than the second area,
The method further includes the computer allocating at least a part of radio resources including the first radio resource and the second radio resource to a third roadside device installed in the third area. Item 2. The radio resource allocation method according to Item 1. Allocating at least a part of the first radio resource to the first roadside device is performed based on a first algorithm for radio resource allocation;
Allocating at least a portion of the second radio resource to the second roadside device, it said different from the first algorithm, to claim 1 or claim 2 is performed based on a second algorithm for radio resource allocation The described radio resource allocation method. The first algorithm obtains an interference relationship between the plurality of first roadside devices based on the installation positions of the plurality of first roadside devices, and is included in the first radio resource in the first roadside device. An algorithm that determines which radio resources are allocated,
The second algorithm is an algorithm in which which radio resource included in the second radio resource is allocated in advance for each of a plurality of partial areas that divide the area where the second roadside device is installed. The radio | wireless resource allocation method of Claim 3 . Allocating at least a part of the first radio resource to the first roadside device is to consider the first area and the fourth area as one area and to install the first roadside device in the first area. And allocating at least a part of the first radio resource to a fourth roadside device installed in the fourth area based on a first algorithm for radio resource allocation,
The allocation of at least a part of the second radio resource to the second roadside device is performed based on a second algorithm for radio resource allocation different from the first algorithm . The radio | wireless resource allocation method of any one of Claims . A roadside machine system,
A plurality of first roadside devices installed in a first area included in the target area, to which at least a part of the first radio resource is allocated;
A plurality of second roadside devices installed in a second area included in the target area and assigned with at least a part of a second radio resource different from the first radio resource;
Including
The first area is adjacent to the boundary of the target area,
The second area is adjacent to the first area and is further away from the boundary than the first area ;
The first radio resource is common to a fourth radio resource allocated to a fourth roadside device installed in a fourth area,
The fourth area is a roadside machine system that is included in a non-target area controlled by an organization different from the target area and is adjacent to the boundary . A radio resource allocation method comprising:
The first computer allocates at least a part of the first radio resource to a first roadside device installed in the first area included in the first target area;
The first computer allocates at least a part of a second radio resource different from the first radio resource to a second roadside device installed in a second area included in the first target area;
The second computer allocates at least a part of the fourth radio resource to a fourth roadside device installed in a fourth area included in the second target area;
The second computer allocates at least a part of a fifth radio resource different from the fourth radio resource to a fifth roadside device installed in a fifth area included in the second target area;
Including
The first area is adjacent to a boundary of the first target area;
The second area is adjacent to the first area and is further away from the boundary than the first area;
The second target area is governed by an organization different from the first target area, adjacent to the boundary,
The fourth area is adjacent to the boundary,
The fifth area is adjacent to the fourth area and is further away from the boundary than the fourth area ;
The first radio resource is common with the fourth radio resource.
Radio resource allocation method. Computer
A computer program for causing a processing unit and a storage unit to store area information indicating positions of the first area and the second area included in the target area,
The first area is adjacent to the boundary of the target area,
The second area is adjacent to the first area and is further away from the boundary than the first area;
The processor is
Get the location information where the roadside machine is installed,
Based on the area information, when it is determined that the installation position of the roadside machine indicated by the position information is included in the first area, the roadside machine is determined as a target of the first allocation process,
When it is determined that the installation position of the roadside device indicated by the position information is included in the second area based on the area information, the processing includes determining the roadside device as a target of second allocation processing. Done
The first allocation process is a process of allocating at least a part of the first radio resource to a roadside device installed in the first area,
The second allocation process, the roadside device installed in the second area, Ri processing der allocating at least part of a different second wireless resource to the first radio resource,
The first radio resource is common to a fourth radio resource allocated to a fourth roadside device installed in a fourth area,
The fourth area is a computer program that is included in a non-target area controlled by an organization different from the target area and is adjacent to the boundary .