WO2021039587A1 - Wireless communication system - Google Patents

Wireless communication system Download PDF

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Publication number
WO2021039587A1
WO2021039587A1 PCT/JP2020/031461 JP2020031461W WO2021039587A1 WO 2021039587 A1 WO2021039587 A1 WO 2021039587A1 JP 2020031461 W JP2020031461 W JP 2020031461W WO 2021039587 A1 WO2021039587 A1 WO 2021039587A1
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radio
wireless
communication system
wireless communication
station
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PCT/JP2020/031461
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French (fr)
Japanese (ja)
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慶 柳澤
達也 阿部
雅之 石▲ざき▼
清志 山本
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株式会社日立国際電気
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Priority to JP2021542813A priority Critical patent/JPWO2021039587A1/ja
Publication of WO2021039587A1 publication Critical patent/WO2021039587A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/06—Optimizing the usage of the radio link, e.g. header compression, information sizing, discarding information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/04—Terminal devices adapted for relaying to or from another terminal or user

Definitions

  • the present invention relates to a time-division relay type wireless communication system having a network topology in which a plurality of wireless stations are connected.
  • the time-divided relay type wireless communication system is a system that has a plurality of wireless stations such as a base station, a relay station, and a terminal station, and can perform data transmission by wireless relay using these wireless stations.
  • wireless communication systems are used, for example, for transmitting camera images taken at remote locations, and are being applied to fields such as medical care, disaster prevention, and disaster mitigation.
  • a control scheduler as shown in FIG. 5 is used.
  • the control scheduler shown in the figure is connected to a radio of a base station, which is a type of radio station, and includes a sensing result aggregation unit 201, an optimum topology calculation unit 202, and a radio frame allocation unit 203.
  • the sensing result (received power and radio quality measured for a radio station other than the one connected to the own station) by each radio station in the relay network is sent to the sensing result aggregation unit 201 of the control scheduler.
  • the optimum topology calculation unit 202 calculates the optimum network topology based on the sensing result.
  • the wireless frame allocation unit 203 allocates the requested number of frames to each wireless station in the relay network.
  • Patent Document 1 discloses an invention in which the allocation of wireless frames is devised in order to suppress the reduction of the communication area.
  • the conventional time-division relay method has a problem that the amount of data transmission decreases as the number of connected radio stations increases. This is because the control scheduler connected to the base station does not manage the frame in which the radio stations under the base station communicate in time, and each radio station connects directly underneath. This is because it is a distributed control that allocates radio frames in order to the radio stations. Therefore, even in a wireless section that is not affected by radio wave interference, wireless frames cannot be reused in time (that is, duplicate allocation of wireless frames), and as a result, data increases as the number of wireless stations connected increases. The amount of transmission was supposed to decrease.
  • the network topology generally represents a connection state when two or more wireless stations maintain a wireless connection, and may include a connection with a wired network.
  • BS represents a base station which is an example of a radio station
  • RS1 to RS6 represent a relay station which is another example of a radio station.
  • the solid line arrow between the radio stations indicates that the two radio stations are actually wirelessly connected
  • the broken line arrow between the radio stations indicates that the two radio stations can be wirelessly connected according to the sensing result. It represents that.
  • the frame allocation is as shown in FIG. That is, since the allocation is such that the wireless frames do not overlap in all the wireless sections, the data transmission amount decreases as the number of connected wireless stations increases, and the communication efficiency decreases.
  • the present invention has been made in view of the above-mentioned conventional circumstances, and provides a wireless communication system capable of suppressing a decrease in data transmission amount due to an increase in the number of connected wireless stations.
  • the purpose is to suppress a decrease in data transmission amount due to an increase in the number of connected wireless stations.
  • the wireless communication system is configured as follows. That is, in a time-division relay type wireless communication system having a network topology in which a plurality of wireless stations are connected, a wireless station other than the wireless station connected to the wireless station detected by each of the plurality of wireless stations Calculation unit that collects the sensing results of the above, a calculation unit that calculates the allocation mode of the radio frame for all the radio sections in the network topology based on the sensing result collected by the collection unit, and the calculation unit. It is characterized by including an allocation unit that allocates radio frames to all radio sections in the network topology according to the assigned allocation mode.
  • the calculation unit specifies a combination of radio sections that are not affected by radio wave interference based on the sensing result collected by the collection unit, and allows duplication of radio frames in the combination of the specified radio sections. It may be configured to calculate the assigned allocation mode.
  • the radio station senses a known signal transmitted from a radio station other than the radio station connected to its own station to measure received power or radio quality, and the measured value is sent to the collection unit as a sensing result. It may be configured to transmit.
  • the present invention it is possible to provide a wireless communication system capable of suppressing a decrease in data transmission amount due to an increase in the number of connected wireless stations.
  • FIG. 2 shows a configuration example of a control scheduler used in the wireless communication system according to the embodiment of the present invention.
  • the control scheduler of this example is connected to the radio of a base station, which is a kind of radio station, and has a sensing result aggregation unit 101, an optimum topology calculation unit 102, a radio frame allocation unit 103, and an optimum time frame allocation. It is provided with a calculation unit 104.
  • the sensing result aggregation unit 101 collects the sensing results of each radio station in the relay network.
  • each radio station senses a known signal (for example, preamble) transmitted from a radio station other than the radio station connected to its own station, and senses the received power and the measured value of the radio quality. Has been acquired as. Then, each radio station aggregates the sensing results in the sensing result aggregation unit 101 by transmitting the sensing results in response to a request from the sensing result aggregation unit 101 or spontaneously.
  • a known signal for example, preamble
  • the optimum topology calculation unit 102 calculates the optimum network topology based on the sensing results of each radio station aggregated in the sensing result aggregation unit 101. As a result, if the optimum network topology is different from the current network topology, the radio station that needs to change the connection destination of the radio link is instructed to switch the radio link so that the optimum network topology can be realized. And rebuild the network topology. Reconstruction of the network topology is performed when the optimum network topology changes due to the movement of radio stations or changes in the communication environment, when a new radio station enters the relay network, or when one of the radio stations enters the relay network. It is also performed when leaving the relay network.
  • the optimum time frame allocation calculation unit 104 calculates a radio frame allocation mode for each radio section in the network topology based on the sensing results by each radio station aggregated in the sensing result aggregation unit 101.
  • the radio frame allocation unit 103 notifies each radio station of the radio frames that can be used by the radio station according to the calculation result by the optimum time frame allocation calculation unit 104. That is, the radio frame allocation unit 103 centrally controls the allocation of radio frames for all the radio sections in the relay network.
  • the specific processing content of the optimum time frame allocation calculation unit 104 will be described using the network topology shown in FIG.
  • the network topology in the figure consists of one base station (BS) and six relay stations (RS1 to RS6), including BS and RS1, RS1 and RS2, RS2 and RS3, RS3 and RS4, and RS4.
  • RS5, and RS5 and RS5 are actually wirelessly connected. That is, a network topology (BS-RS1-RS2-RS3-RS4-RS5-RS6) having six radio sections connected in series in multiple stages is formed.
  • the optimum time frame allocation calculation unit 104 first considers these connection information (information on the radio section) and the sensing results by each radio station aggregated in the sensing result aggregation unit 101, as shown in FIG. Create a matrix.
  • the combinations in the wireless connection state are indicated by " ⁇ "
  • the wireless connection is possible according to the sensing result.
  • the found combinations are represented by " ⁇ ”
  • the combinations that could not be detected by sensing are represented by "x”.
  • the optimum time frame allocation calculation unit 104 analyzes the above matrix and calculates a combination in which the wireless frames can be reused in time (a combination in which the wireless frames can be allocated in duplicate).
  • a procedure for identifying a reusable radio frame in the radio section of RS4 and RS5 will be described. First, the combinations of radio stations that could not be detected by sensing in both RS4 and RS5 (radio stations with a common "x") are listed. That is, the radio sections that are not affected by radio wave interference are listed for both RS4 and RS5.
  • the radio stations that could not be detected by sensing in both RS4 and RS5 are BS, RS1 and RS2, three combinations of BS and RS1, BS and RS2, and RS1 and RS2 are listed.
  • the wireless stations that are actually connected wirelessly are picked up from these, two wireless sections of BS and RS1 and RS1 and RS2 are picked up. Therefore, it is determined that the optimum time frame allocation calculation unit 104 can reuse the radio frames assigned to the radio sections of BS and RS1 or RS1 and RS2 for the radio sections of RS4 and RS5. .. If the same calculation is performed for the radio sections of RS4 and RS5, it is determined that the radio frames assigned to the radio sections of BS and RS1, RS1 and RS2, or RS2 and RS3 can be reused.
  • FIG. 4 shows an example of radio frame allocation in consideration of the matrix of FIG.
  • the radio frames assigned to the radio sections of BS and RS1 are reused.
  • the radio frames assigned to the radio sections of BS and RS1 are reused.
  • a total of 3 frames of radio frames are reused, so that the total number of radio frames used in the entire section between BS and RS6 is reduced from 21 frames to 18 frames.
  • the amount of data transmitted from the terminal radio station will increase by about 18%.
  • the reuse mode of the radio frame shown in FIG. 4 is only an example, and of course, a radio frame of another radio section determined to be reusable in time may be assigned.
  • the sensing result aggregation unit 101 of the control scheduler is a wireless station connected to the wireless station detected by each of the plurality of wireless stations in the network topology.
  • the optimum time frame allocation calculation unit 104 of the control scheduler collects the sensing results for radio stations other than the above, and based on the sensing results collected by the sensing result aggregation unit 101, the radio for all the radio sections in the network topology.
  • the frame allocation mode is calculated, and the radio frame allocation unit 103 of the control scheduler allocates radio frames to all the radio sections in the network topology according to the allocation mode calculated by the optimum time frame allocation calculation unit 104. It is configured as follows.
  • control scheduler centrally controls the allocation of radio frames to all the radio sections in the network topology based on the sensing results detected by each of the plurality of radio stations in the network topology. doing. Therefore, even if the number of connected wireless stations increases, the wireless frames can be allocated without waste in consideration of the sensing result of each wireless device, so that it is possible to suppress a decrease in the amount of data transmission.
  • the optimum time frame allocation calculation unit 104 identifies a combination of radio sections that are not affected by radio wave interference based on the sensing results collected by the sensing result aggregation unit 101, and the specified radio section It is configured to calculate an allocation mode that allows duplication of radio frames in combination. As a result, it is possible to optimize the allocation of wireless frames within the range not affected by radio wave interference, and it is possible to realize efficient data transmission.
  • the term "radio section that is not affected by radio wave interference” is not limited to a radio section that is not affected by radio wave interference at all, and is not limited to a radio section that is not affected by radio wave interference, that is, radio wave interference. It also includes radio sections that are present but do not interfere with wireless communication.
  • each radio station senses a known signal (for example, a preamble) transmitted from a radio station other than the radio station connected to its own station to measure received power or radio quality, and measures the received power or radio quality.
  • the measurement value is transmitted to the collecting unit as a sensing result. In this way, since the sensing is performed by using the function provided by the conventional radio station, it is not necessary to add the function for sensing to each radio.
  • the sensing result aggregation unit 101 realizes the function of the collection unit according to the present invention
  • the optimum time frame allocation calculation unit 104 realizes the function of the calculation unit according to the present invention
  • the wireless frame allocation unit 103 has realized the function of the allocation unit according to the present invention, but each function according to the present invention may be realized by another configuration. Further, in this example, each function according to the present invention is realized by a single device (control scheduler), but it may be realized by a plurality of devices connected so as to be able to communicate with each other.
  • the present invention has been described in detail above, it goes without saying that the present invention is not limited to the above-described configuration and may be realized by a configuration other than the above. Further, the present invention provides, for example, a method or method for executing the process according to the present invention, a program for realizing such a method or method by a computer having hardware resources such as a processor or memory, and such a program. It is also possible to provide it as a storage medium for storing.
  • the present invention can be used in a time-division relay type wireless communication system having a network topology in which a plurality of wireless stations are connected.
  • BS Base station
  • RS1 to RS6 Relay station 101,201: Sensing result aggregation unit, 102,202: Optimal topology calculation unit, 103,203: Wireless frame allocation unit, 104: Optimal time frame allocation calculation unit

Abstract

Provided is a wireless communication system capable of suppressing a reduction in a data transfer amount caused by an increase in the number of connected wireless stations. A sensing result aggregation unit 101 collects sensing results that are detected by each of a plurality of wireless stations in a network topology relating to a wireless station other than wireless stations connected to the plurality of wireless stations. An appropriate time frame allocation calculation unit 104 calculates, on the basis of the sensing results collected by the sensing result aggregation unit 101, an allocation mode of wireless frames with respect to all wireless sections in the network topology. A wireless frame allocation unit 103 allocates, in accordance with the allocation mode calculated by the appropriate time frame allocation calculation unit 104, the wireless frames with respect to the all wireless sections in the network topology.

Description

無線通信システムWireless communication system
　本発明は、複数の無線局を接続したネットワークトポロジを有する時分割中継方式の無線通信システムに関する。 The present invention relates to a time-division relay type wireless communication system having a network topology in which a plurality of wireless stations are connected.
　時分割中継方式の無線通信システムは、基地局、中継局、端末局などの複数の無線局を有し、これら無線局を用いた無線中継によりデータ伝送を行うことが可能なシステムである。このような無線通信システムは、例えば、遠隔地で撮影したカメラ映像を伝送する用途などで使用されており、医療、防災・減災などの分野への適用も進められている。従来の時分割中継方式の無線通信システムでは、図５に示すような制御用スケジューラが使用されている。同図の制御用スケジューラは、無線局の一種である基地局の無線機に接続されており、センシング結果集約部２０１と、最適トポロジ算出部２０２と、無線フレーム割当部２０３とを備えている。 The time-divided relay type wireless communication system is a system that has a plurality of wireless stations such as a base station, a relay station, and a terminal station, and can perform data transmission by wireless relay using these wireless stations. Such wireless communication systems are used, for example, for transmitting camera images taken at remote locations, and are being applied to fields such as medical care, disaster prevention, and disaster mitigation. In the conventional time-division relay type wireless communication system, a control scheduler as shown in FIG. 5 is used. The control scheduler shown in the figure is connected to a radio of a base station, which is a type of radio station, and includes a sensing result aggregation unit 201, an optimum topology calculation unit 202, and a radio frame allocation unit 203.
　従来の時分割中継方式では、中継ネットワーク内の各無線局によるセンシング結果（自局が接続している以外の無線局について測定した受信電力や無線品質）を制御用スケジューラのセンシング結果集約部２０１に集約し、最適トポロジ算出部２０２がセンシング結果に基づいて最適なネットワークトポロジを算出している。また、時分割による無線フレームの割り当てについては、無線フレーム割当部２０３が中継ネットワーク内の各無線局に対して要求されたフレーム数を割り当てている。 In the conventional time-division relay method, the sensing result (received power and radio quality measured for a radio station other than the one connected to the own station) by each radio station in the relay network is sent to the sensing result aggregation unit 201 of the control scheduler. Aggregated, the optimum topology calculation unit 202 calculates the optimum network topology based on the sensing result. Further, regarding the allocation of wireless frames by time division, the wireless frame allocation unit 203 allocates the requested number of frames to each wireless station in the relay network.
　なお、複数の無線局間の無線フレームの割り当てについて、これまでに種々の発明が提案されている。例えば、特許文献１には、通信エリアの縮小化を抑制するために、無線フレームの割り当てを工夫する発明が開示されている。 It should be noted that various inventions have been proposed so far regarding the allocation of wireless frames between a plurality of wireless stations. For example, Patent Document 1 discloses an invention in which the allocation of wireless frames is devised in order to suppress the reduction of the communication area.
国際公開第２０１８／０１６０６０号International Publication No. 2018/016060
　従来の時分割中継方式は、原理的に、無線局の接続台数が増えればその分のデータ伝送量が減少してしまうという問題がある。これは、基地局に接続された制御用スケジューラが、その基地局配下の無線局が時間的にどのフレームで通信を行っているかまでは管理しておらず、各々の無線局が直下に接続している無線局に対して順番に無線フレームを割り当てる分散型制御となっているためである。このため、電波干渉の影響がない無線区間でも、無線フレームを時間的に再利用すること（つまり、無線フレームの重複割り当て）ができず、その結果、無線局の接続台数の増大に伴ってデータ伝送量が減少してしまうことになっていた。 In principle, the conventional time-division relay method has a problem that the amount of data transmission decreases as the number of connected radio stations increases. This is because the control scheduler connected to the base station does not manage the frame in which the radio stations under the base station communicate in time, and each radio station connects directly underneath. This is because it is a distributed control that allocates radio frames in order to the radio stations. Therefore, even in a wireless section that is not affected by radio wave interference, wireless frames cannot be reused in time (that is, duplicate allocation of wireless frames), and as a result, data increases as the number of wireless stations connected increases. The amount of transmission was supposed to decrease.
　上記の問題について、図１に示すネットワークトポロジを用いて説明する。ここで、ネットワークトポロジとは、一般に、２台以上の無線局同士が無線接続を維持しているときの接続状態を表すものであり、有線ネットワークとの接続を含む場合もある。図１において、ＢＳは、無線局の一例である基地局を表し、ＲＳ１～ＲＳ６は、無線局の別の例である中継局を表している。また、無線局間の実線矢印は、２つの無線局が実際に無線接続していることを表し、無線局間の破線矢印は、センシング結果によれば２つの無線局が無線接続が可能であることを表している。 The above problem will be described using the network topology shown in FIG. Here, the network topology generally represents a connection state when two or more wireless stations maintain a wireless connection, and may include a connection with a wired network. In FIG. 1, BS represents a base station which is an example of a radio station, and RS1 to RS6 represent a relay station which is another example of a radio station. Further, the solid line arrow between the radio stations indicates that the two radio stations are actually wirelessly connected, and the broken line arrow between the radio stations indicates that the two radio stations can be wirelessly connected according to the sensing result. It represents that.
　従来方式では、単純に各無線局が自局の直下に接続している無線局に対してのみ無線フレームの割り当てを行うため、図６のようなフレーム割り当てとなる。すなわち、全ての無線区間で無線フレームの重複が無いような割り当てとなるので、無線局の接続台数が増えるほどデータ伝送量が減少してしまい、通信効率が低下することになる。 In the conventional method, since each radio station simply allocates a radio frame only to a radio station connected directly under its own station, the frame allocation is as shown in FIG. That is, since the allocation is such that the wireless frames do not overlap in all the wireless sections, the data transmission amount decreases as the number of connected wireless stations increases, and the communication efficiency decreases.
　本発明は、上記のような従来の事情に鑑みて為されたものであり、無線局の接続台数の増加に伴うデータ伝送量の減少を抑制することが可能な無線通信システムを提供することを目的とする。 The present invention has been made in view of the above-mentioned conventional circumstances, and provides a wireless communication system capable of suppressing a decrease in data transmission amount due to an increase in the number of connected wireless stations. The purpose.
　本発明では、上記目的を達成するために、無線通信システムを以下のように構成した。
　すなわち、複数の無線局を接続したネットワークトポロジを有する時分割中継方式の無線通信システムにおいて、前記複数の無線局の各々により検出された、該無線局と接続状態にある無線局以外の無線局についてのセンシング結果を収集する収集部と、前記収集部により収集されたセンシング結果に基づいて、前記ネットワークトポロジ内の全ての無線区間に対する無線フレームの割り当て態様を算出する算出部と、前記算出部により算出された割り当て態様に従って、前記ネットワークトポロジ内の全ての無線区間に対する無線フレームの割り当てを行う割当部と、を備えたことを特徴とする。 In the present invention, in order to achieve the above object, the wireless communication system is configured as follows.
That is, in a time-division relay type wireless communication system having a network topology in which a plurality of wireless stations are connected, a wireless station other than the wireless station connected to the wireless station detected by each of the plurality of wireless stations Calculation unit that collects the sensing results of the above, a calculation unit that calculates the allocation mode of the radio frame for all the radio sections in the network topology based on the sensing result collected by the collection unit, and the calculation unit. It is characterized by including an allocation unit that allocates radio frames to all radio sections in the network topology according to the assigned allocation mode.
　ここで、前記算出部は、前記収集部により収集されたセンシング結果に基づいて、電波干渉の影響がない無線区間の組み合わせを特定し、前記特定した無線区間の組み合わせでの無線フレームの重複を許容した割り当て態様を算出する構成であってもよい。 Here, the calculation unit specifies a combination of radio sections that are not affected by radio wave interference based on the sensing result collected by the collection unit, and allows duplication of radio frames in the combination of the specified radio sections. It may be configured to calculate the assigned allocation mode.
　また、前記無線局は、自局と接続状態にある無線局以外の無線局から送信される既知信号をセンシングして受信電力又は無線品質を測定し、その測定値をセンシング結果として前記収集部へ送信する構成であってもよい。 In addition, the radio station senses a known signal transmitted from a radio station other than the radio station connected to its own station to measure received power or radio quality, and the measured value is sent to the collection unit as a sensing result. It may be configured to transmit.
　本発明によれば、無線局の接続台数の増加に伴うデータ伝送量の減少を抑制することが可能な無線通信システムを提供することができる。 According to the present invention, it is possible to provide a wireless communication system capable of suppressing a decrease in data transmission amount due to an increase in the number of connected wireless stations.
多段中継のネットワークトポロジの構成例を示す図である。It is a figure which shows the configuration example of the network topology of multi-stage relay. 本発明の一実施形態に係る無線通信システムで使用される制御用スケジューラの構成例を示す図である。It is a figure which shows the configuration example of the control scheduler used in the wireless communication system which concerns on one Embodiment of this invention. 本発明方式の無線フレーム割り当ての際に使用されるマトリクスの例を示す図である。It is a figure which shows the example of the matrix used at the time of the radio frame allocation of the present invention method. 本発明方式による無線フレームの割り当て例を示す図である。It is a figure which shows the allocation example of the wireless frame by the method of this invention. 従来方式の無線通信システムで使用される制御用スケジューラの構成例を示す図である。It is a figure which shows the configuration example of the control scheduler used in the conventional type wireless communication system. 従来方式による無線フレームの割り当て例を示す図である。It is a figure which shows the allocation example of the wireless frame by the conventional method.
　本発明の一実施形態に係る無線通信システムについて、図面を参照して説明する。
　以下では、図１に示したネットワークトポロジを有する無線通信システムを例にして説明する。図２には、本発明の一実施形態に係る無線通信システムで使用される制御用スケジューラの構成例を示してある。
　本例の制御用スケジューラは、無線局の一種である基地局の無線機に接続されており、センシング結果集約部１０１と、最適トポロジ算出部１０２と、無線フレーム割当部１０３と、最適時間フレーム割当算出部１０４とを備えている。 A wireless communication system according to an embodiment of the present invention will be described with reference to the drawings.
In the following, a wireless communication system having the network topology shown in FIG. 1 will be described as an example. FIG. 2 shows a configuration example of a control scheduler used in the wireless communication system according to the embodiment of the present invention.
The control scheduler of this example is connected to the radio of a base station, which is a kind of radio station, and has a sensing result aggregation unit 101, an optimum topology calculation unit 102, a radio frame allocation unit 103, and an optimum time frame allocation. It is provided with a calculation unit 104.
　センシング結果集約部１０１は、中継ネットワーク内の各無線局によるセンシング結果を収集する。本例では、それぞれの無線局が、自局と接続状態にある無線局以外の無線局から送信される既知信号（例えば、プリアンブル）をセンシングし、その受信電力や無線品質の測定値をセンシング結果として取得している。そして、それぞれの無線局が、センシング結果集約部１０１からの要求に応じて又は自発的にセンシング結果を送信することで、センシング結果集約部１０１にセンシング結果を集約させている。 The sensing result aggregation unit 101 collects the sensing results of each radio station in the relay network. In this example, each radio station senses a known signal (for example, preamble) transmitted from a radio station other than the radio station connected to its own station, and senses the received power and the measured value of the radio quality. Has been acquired as. Then, each radio station aggregates the sensing results in the sensing result aggregation unit 101 by transmitting the sensing results in response to a request from the sensing result aggregation unit 101 or spontaneously.
　最適トポロジ算出部１０２は、センシング結果集約部１０１に集約された各無線局によるセンシング結果に基づいて、最適なネットワークトポロジを算出する。その結果、最適なネットワークトポロジが現在のネットワークトポロジと異なる場合には、最適なネットワークトポロジが実現されるように、無線リンクの接続先の変更が必要な無線局に対して無線リンクの切り替えを指示し、ネットワークトポロジを再構築する。ネットワークトポロジの再構築は、無線局の移動や通信環境の変化などに伴って最適なネットワークトポロジが変化した場合のほか、新たな無線局が中継ネットワークに参入する場合や、いずれかの無線局が中継ネットワークから離脱する場合などにも行われる。 The optimum topology calculation unit 102 calculates the optimum network topology based on the sensing results of each radio station aggregated in the sensing result aggregation unit 101. As a result, if the optimum network topology is different from the current network topology, the radio station that needs to change the connection destination of the radio link is instructed to switch the radio link so that the optimum network topology can be realized. And rebuild the network topology. Reconstruction of the network topology is performed when the optimum network topology changes due to the movement of radio stations or changes in the communication environment, when a new radio station enters the relay network, or when one of the radio stations enters the relay network. It is also performed when leaving the relay network.
　最適時間フレーム割当算出部１０４は、センシング結果集約部１０１に集約された各無線局によるセンシング結果に基づいて、ネットワークトポロジ内の各無線区間に対する無線フレームの割り当て態様を算出する。
　無線フレーム割当部１０３は、最適時間フレーム割当算出部１０４による算出結果に従って、各無線局に対して、その無線局が使用可能な無線フレームを通知する。すなわち、無線フレーム割当部１０３が、中継ネットワーク内の全ての無線区間について無線フレームの割り当てを集中制御する。 The optimum time frame allocation calculation unit 104 calculates a radio frame allocation mode for each radio section in the network topology based on the sensing results by each radio station aggregated in the sensing result aggregation unit 101.
The radio frame allocation unit 103 notifies each radio station of the radio frames that can be used by the radio station according to the calculation result by the optimum time frame allocation calculation unit 104. That is, the radio frame allocation unit 103 centrally controls the allocation of radio frames for all the radio sections in the relay network.
　最適時間フレーム割当算出部１０４の具体的な処理内容について、図１に示すネットワークトポロジを用いて説明する。同図のネットワークトポロジは、１台の基地局（ＢＳ）と６台の中継局（ＲＳ１～ＲＳ６）で構成されており、ＢＳとＲＳ１、ＲＳ１とＲＳ２、ＲＳ２とＲＳ３、ＲＳ３とＲＳ４、ＲＳ４とＲＳ５、およびＲＳ５とＲＳ５が実際に無線接続している。つまり、直列に多段接続された６つの無線区間を持つネットワークトポロジ（ＢＳ－ＲＳ１－ＲＳ２－ＲＳ３－ＲＳ４－ＲＳ５－ＲＳ６）が形成されている。 The specific processing content of the optimum time frame allocation calculation unit 104 will be described using the network topology shown in FIG. The network topology in the figure consists of one base station (BS) and six relay stations (RS1 to RS6), including BS and RS1, RS1 and RS2, RS2 and RS3, RS3 and RS4, and RS4. RS5, and RS5 and RS5 are actually wirelessly connected. That is, a network topology (BS-RS1-RS2-RS3-RS4-RS5-RS6) having six radio sections connected in series in multiple stages is formed.
　最適時間フレーム割当算出部１０４は、まず、これらの接続情報（無線区間の情報）と、センシング結果集約部１０１に集約された各無線局によるセンシング結果とを考慮して、図３に示すようなマトリクスを作成する。図３のマトリクスは、中継ネットワーク内の全ての無線局（ＢＳ，ＲＳ１～ＲＳ６）の組み合わせについて、無線接続の状態にある組み合わせを「◎」で表し、センシング結果により無線接続が可能であることが判明した組み合わせを「〇」で表し、センシング検出できなかった組み合わせ（無線接続できない組み合わせ）を「×」で表している。 The optimum time frame allocation calculation unit 104 first considers these connection information (information on the radio section) and the sensing results by each radio station aggregated in the sensing result aggregation unit 101, as shown in FIG. Create a matrix. In the matrix of FIG. 3, for all the combinations of wireless stations (BS, RS1 to RS6) in the relay network, the combinations in the wireless connection state are indicated by "◎", and the wireless connection is possible according to the sensing result. The found combinations are represented by "○", and the combinations that could not be detected by sensing (combinations that cannot be wirelessly connected) are represented by "x".
　最適時間フレーム割当算出部１０４は、上記のマトリクスを分析し、無線フレームを時間的に再利用することが可能な組み合わせ（無線フレームを重複して割り当てても支障がない組み合わせ）を算出する。
　一例として、ＲＳ４とＲＳ５の無線区間で再利用可能な無線フレームを特定する手順について説明する。まず、ＲＳ４、ＲＳ５ともにセンシング検出できなかった無線局同士（「×」が共通についている無線局同士）の組み合わせをリストアップする。つまり、ＲＳ４、ＲＳ５の両方に対して電波干渉の影響がない無線区間をリストアップする。本例では、ＲＳ４、ＲＳ５ともにセンシング検出できなかった無線局はＢＳ、ＲＳ１、ＲＳ２であるため、ＢＳとＲＳ１、ＢＳとＲＳ２、ＲＳ１とＲＳ２の３つの組み合わせがリストアップされる。この中から実際に無線接続中の無線局同士をピックアップすると、ＢＳとＲＳ１、ＲＳ１とＲＳ２の２つの無線区間がピックアップされる。したがって、最適時間フレーム割当算出部１０４は、ＲＳ４とＲＳ５の無線区間については、ＢＳとＲＳ１、又はＲＳ１とＲＳ２の無線区間に割り当てられた無線フレームを再利用することが可能であると判断される。
　ＲＳ４とＲＳ５の無線区間について同様に計算すると、ＢＳとＲＳ１、ＲＳ１とＲＳ２、又はＲＳ２とＲＳ３の無線区間に割り当てられた無線フレームを再利用することが可能であると判断される。 The optimum time frame allocation calculation unit 104 analyzes the above matrix and calculates a combination in which the wireless frames can be reused in time (a combination in which the wireless frames can be allocated in duplicate).
As an example, a procedure for identifying a reusable radio frame in the radio section of RS4 and RS5 will be described. First, the combinations of radio stations that could not be detected by sensing in both RS4 and RS5 (radio stations with a common "x") are listed. That is, the radio sections that are not affected by radio wave interference are listed for both RS4 and RS5. In this example, since the radio stations that could not be detected by sensing in both RS4 and RS5 are BS, RS1 and RS2, three combinations of BS and RS1, BS and RS2, and RS1 and RS2 are listed. When the wireless stations that are actually connected wirelessly are picked up from these, two wireless sections of BS and RS1 and RS1 and RS2 are picked up. Therefore, it is determined that the optimum time frame allocation calculation unit 104 can reuse the radio frames assigned to the radio sections of BS and RS1 or RS1 and RS2 for the radio sections of RS4 and RS5. ..
If the same calculation is performed for the radio sections of RS4 and RS5, it is determined that the radio frames assigned to the radio sections of BS and RS1, RS1 and RS2, or RS2 and RS3 can be reused.
　図４には、図３のマトリクスを考慮した無線フレームの割り当て例を示してある。同図では、ＲＳ４とＲＳ５の無線区間について、ＢＳとＲＳ１の無線区間に割り当てられた無線フレームを再利用している。また、ＲＳ５とＲＳ６の無線区間についても、ＢＳとＲＳ１の無線区間に割り当てられた無線フレームを再利用している。これにより、合わせて３フレーム分の無線フレームを再利用するので、ＢＳとＲＳ６の間の全体的な区間で使用される無線フレーム数の合計が２１フレームから１８フレームに減少する。その結果、末端の無線局からのデータ伝送量が１８％程度増加することになる。なお、図４に示した無線フレームの再利用態様は一例に過ぎず、当然ながら、時間的に再利用が可能と判断された他の無線区間の無線フレームを割り当ててもよい。 FIG. 4 shows an example of radio frame allocation in consideration of the matrix of FIG. In the figure, for the radio sections of RS4 and RS5, the radio frames assigned to the radio sections of BS and RS1 are reused. Further, as for the radio sections of RS5 and RS6, the radio frames assigned to the radio sections of BS and RS1 are reused. As a result, a total of 3 frames of radio frames are reused, so that the total number of radio frames used in the entire section between BS and RS6 is reduced from 21 frames to 18 frames. As a result, the amount of data transmitted from the terminal radio station will increase by about 18%. The reuse mode of the radio frame shown in FIG. 4 is only an example, and of course, a radio frame of another radio section determined to be reusable in time may be assigned.
　以上のように、本例の無線通信システムは、制御用スケジューラのセンシング結果集約部１０１が、ネットワークトポロジ内にある複数の無線局の各々により検出された、該無線局と接続状態にある無線局以外の無線局についてのセンシング結果を収集し、制御用スケジューラの最適時間フレーム割当算出部１０４が、センシング結果集約部１０１により収集されたセンシング結果に基づいて、ネットワークトポロジ内の全ての無線区間に対する無線フレームの割り当て態様を算出し、制御用スケジューラの無線フレーム割当部１０３が、最適時間フレーム割当算出部１０４により算出された割り当て態様に従って、前記ネットワークトポロジ内の全ての無線区間に対する無線フレームの割り当てを行うように構成されている。 As described above, in the wireless communication system of this example, the sensing result aggregation unit 101 of the control scheduler is a wireless station connected to the wireless station detected by each of the plurality of wireless stations in the network topology. The optimum time frame allocation calculation unit 104 of the control scheduler collects the sensing results for radio stations other than the above, and based on the sensing results collected by the sensing result aggregation unit 101, the radio for all the radio sections in the network topology. The frame allocation mode is calculated, and the radio frame allocation unit 103 of the control scheduler allocates radio frames to all the radio sections in the network topology according to the allocation mode calculated by the optimum time frame allocation calculation unit 104. It is configured as follows.
　このように、本例では、制御用スケジューラが、ネットワークトポロジ内にある複数の無線局の各々により検出されたセンシング結果に基づいて、ネットワークトポロジ内の全ての無線区間に対する無線フレームの割り当てを集中制御している。このため、無線局の接続台数が増えても、各無線機のセンシング結果を考慮して無線フレームを無駄なく割り当てることができるため、データ伝送量の減少を抑制することが可能となる。 As described above, in this example, the control scheduler centrally controls the allocation of radio frames to all the radio sections in the network topology based on the sensing results detected by each of the plurality of radio stations in the network topology. doing. Therefore, even if the number of connected wireless stations increases, the wireless frames can be allocated without waste in consideration of the sensing result of each wireless device, so that it is possible to suppress a decrease in the amount of data transmission.
　また、本例では、最適時間フレーム割当算出部１０４が、センシング結果集約部１０１により収集されたセンシング結果に基づいて、電波干渉の影響がない無線区間の組み合わせを特定し、当該特定した無線区間の組み合わせでの無線フレームの重複を許容した割り当て態様を算出するように構成されている。これにより、電波干渉の影響がない範囲で無線フレームの割り当てを最適化することが可能となり、効率的なデータ伝送を実現することができる。なお、ここでいう「電波干渉の影響がない無線区間」とは、電波干渉の影響が全くない無線区間に限定するものではなく、電波干渉の影響が実質的にない無線区間、すなわち、電波干渉があるものの無線通信に支障をきたす程度ではない無線区間も含むものである。 Further, in this example, the optimum time frame allocation calculation unit 104 identifies a combination of radio sections that are not affected by radio wave interference based on the sensing results collected by the sensing result aggregation unit 101, and the specified radio section It is configured to calculate an allocation mode that allows duplication of radio frames in combination. As a result, it is possible to optimize the allocation of wireless frames within the range not affected by radio wave interference, and it is possible to realize efficient data transmission. The term "radio section that is not affected by radio wave interference" is not limited to a radio section that is not affected by radio wave interference at all, and is not limited to a radio section that is not affected by radio wave interference, that is, radio wave interference. It also includes radio sections that are present but do not interfere with wireless communication.
　また、本例では、各々の無線局が、自局と接続状態にある無線局以外の無線局から送信される既知信号（例えば、プリアンブル）をセンシングして受信電力又は無線品質を測定し、その測定値をセンシング結果として前記収集部へ送信する構成となっている。このように、従来の無線局が備えている機能を利用してセンシングを行うので、センシングのための機能を各無線機に追加する必要がない。 Further, in this example, each radio station senses a known signal (for example, a preamble) transmitted from a radio station other than the radio station connected to its own station to measure received power or radio quality, and measures the received power or radio quality. The measurement value is transmitted to the collecting unit as a sensing result. In this way, since the sensing is performed by using the function provided by the conventional radio station, it is not necessary to add the function for sensing to each radio.
　ここで、本例では、センシング結果集約部１０１が本発明に係る収集部の機能を実現し、最適時間フレーム割当算出部１０４が本発明に係る算出部の機能を実現し、無線フレーム割当部１０３が本発明に係る割当部の機能を実現しているが、本発明に係る各機能を他の構成により実現しても構わない。また、本例では、本発明に係る各機能を単一の装置（制御スケジューラ）で実現しているが、互いに通信可能に接続された複数台の装置で実現しても構わない。 Here, in this example, the sensing result aggregation unit 101 realizes the function of the collection unit according to the present invention, the optimum time frame allocation calculation unit 104 realizes the function of the calculation unit according to the present invention, and the wireless frame allocation unit 103. Has realized the function of the allocation unit according to the present invention, but each function according to the present invention may be realized by another configuration. Further, in this example, each function according to the present invention is realized by a single device (control scheduler), but it may be realized by a plurality of devices connected so as to be able to communicate with each other.
　以上、本発明について詳細に説明したが、本発明は上記のような構成に限定されるものではなく、上記以外の構成により実現してもよいことは言うまでもない。
　また、本発明は、例えば、本発明に係る処理を実行する方法や方式、そのような方法や方式をプロセッサやメモリ等のハードウェア資源を有するコンピュータにより実現するためのプログラム、そのようなプログラムを記憶する記憶媒体などとして提供することも可能である。 Although the present invention has been described in detail above, it goes without saying that the present invention is not limited to the above-described configuration and may be realized by a configuration other than the above.
Further, the present invention provides, for example, a method or method for executing the process according to the present invention, a program for realizing such a method or method by a computer having hardware resources such as a processor or memory, and such a program. It is also possible to provide it as a storage medium for storing.
　本発明は、複数の無線局を接続したネットワークトポロジを有する時分割中継方式の無線通信システムに利用することができる。 The present invention can be used in a time-division relay type wireless communication system having a network topology in which a plurality of wireless stations are connected.
　ＢＳ：基地局、　ＲＳ１～ＲＳ６：中継局
　１０１，２０１：センシング結果集約部、　１０２，２０２：最適トポロジ算出部、　１０３，２０３：無線フレーム割当部、　１０４：最適時間フレーム割当算出部 BS: Base station, RS1 to RS6: Relay station 101,201: Sensing result aggregation unit, 102,202: Optimal topology calculation unit, 103,203: Wireless frame allocation unit, 104: Optimal time frame allocation calculation unit

Claims (4)

  1. 　複数の無線局を接続したネットワークトポロジを有する時分割中継方式の無線通信システムにおいて、
    　前記複数の無線局の各々により検出された、該無線局と接続状態にある無線局以外の無線局についてのセンシング結果を収集する収集部と、
    　前記収集部により収集されたセンシング結果に基づいて、前記ネットワークトポロジ内の全ての無線区間に対する無線フレームの割り当て態様を算出する算出部と、
    　前記算出部により算出された割り当て態様に従って、前記ネットワークトポロジ内の全ての無線区間に対する無線フレームの割り当てを行う割当部と、を備えたことを特徴とする無線通信システム。     In a time-division relay type wireless communication system having a network topology in which a plurality of wireless stations are connected,
    A collecting unit that collects sensing results of radio stations other than the radio stations connected to the radio stations detected by each of the plurality of radio stations.
    Based on the sensing result collected by the collecting unit, a calculation unit that calculates a radio frame allocation mode for all radio sections in the network topology, and a calculation unit.
    A wireless communication system including an allocation unit that allocates radio frames to all radio sections in the network topology according to an allocation mode calculated by the calculation unit.
  2. 　請求項１に記載の無線通信システムにおいて、
    　前記算出部は、前記収集部により収集されたセンシング結果に基づいて、電波干渉の影響がない無線区間の組み合わせを特定し、前記特定した無線区間の組み合わせでの無線フレームの重複を許容した割り当て態様を算出することを特徴とする無線通信システム。     In the wireless communication system according to claim 1,
    The calculation unit identifies a combination of radio sections that are not affected by radio wave interference based on the sensing result collected by the collection unit, and allows duplication of radio frames in the combination of the specified radio sections. A wireless communication system characterized by calculating.
  3. 　請求項１に記載の無線通信システムにおいて、
    　前記無線局は、自局と接続状態にある無線局以外の無線局から送信される既知信号をセンシングして受信電力又は無線品質を測定し、その測定値をセンシング結果として前記収集部へ送信することを特徴とする無線通信システム。     In the wireless communication system according to claim 1,
    The radio station senses a known signal transmitted from a radio station other than the radio station connected to its own station, measures the received power or radio quality, and transmits the measured value as a sensing result to the collection unit. A wireless communication system characterized by this.
  4. 　請求項２に記載の無線通信システムにおいて、
    　前記無線局は、自局と接続状態にある無線局以外の無線局から送信される既知信号をセンシングして受信電力又は無線品質を測定し、その測定値をセンシング結果として前記収集部へ送信することを特徴とする無線通信システム。     In the wireless communication system according to claim 2,
    The radio station senses a known signal transmitted from a radio station other than the radio station connected to its own station, measures the received power or radio quality, and transmits the measured value as a sensing result to the collection unit. A wireless communication system characterized by this.
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