JP4761306B2 - Wireless communication network system - Google Patents

Description

  The present invention relates to a wireless communication network system, and more particularly to a wireless communication network system that performs wireless communication by selecting a wireless system suitable for a wireless communication environment from a plurality of different wireless systems.

  In recent years, the use of various wireless systems such as mobile phones, PHS (Personal Handyphone System), IEEE802 wireless LAN (Local Area Network), and Bluetooth has been expanded. In ubiquitous communication, a sensor network is configured, and the use of short-range wireless systems such as ZigBee is also expected.

  Such wireless systems are rapidly expanding and diversifying their use, becoming a wireless communication environment in which various wireless systems having different frequency bands and different communication methods are mixed, and various applications are expected to be used. ing.

  On the other hand, since radio resources are limited, there is a concern that radio resources will be depleted as the use of radio systems expands and diversifies. As a technique for solving this problem, a cognitive radio technique has been proposed (Non-Patent Document 1).

And in cognitive radio technology, in a network of a base station equipped with a plurality of different radio systems and a terminal equipped with a plurality of similarly different radio systems, a plurality of radio systems are arranged according to radio communication conditions and user requests. It is a technique that is used properly or used at the same time.
Harada, “Basic study on communication system using cognitive radio”, IEICE Technical Report, SR2005-17, pp. 117-124, 2005. D. Bertsekas, and R. Gallager, Data Networks, Prentice-Hall Inc 1987.

However, in the current cognitive radio network, each of the plurality of radio systems performs radio communication directly between the terminal and the base station, so that each terminal accesses the desired base station with high efficiency. There is a problem that it is difficult to do.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a wireless communication network system capable of accessing a desired base station with high efficiency.

  According to the present invention, the wireless communication network system includes a plurality of base stations, a plurality of wireless devices, and a control unit. The plurality of base stations are equipped with a plurality of mutually different wireless systems, and perform wireless communication using the wireless systems equipped with each. The plurality of wireless devices access at least one base station of the plurality of base stations using at least one wireless system each selected from a plurality of wireless systems and a multi-hop wireless system. The control unit selects at least one radio system from the plurality of radio systems and the multi-hop radio system so that the number of standby traffic in the plurality of radio apparatuses is relatively reduced, and radio communication by the selected at least one radio system And a plurality of wireless devices are controlled to access at least one base station according to the determined route.

  Preferably, the wireless communication network system further includes a route control station. The route control station includes control means, generates route selection information for selecting a route determined by the control means, and transmits the route selection information to a plurality of wireless devices. Each of the plurality of wireless devices includes a plurality of wireless modules, a multi-hop wireless module, and a control module. The plurality of radio modules are provided corresponding to the plurality of base stations, and are equipped with a plurality of different radio systems and access the corresponding base stations via a path for performing radio communication by the radio systems equipped with each. . The multi-hop wireless module accesses one of a plurality of base stations via a path for realizing wireless communication by the multi-hop wireless system. The control module integrally controls the plurality of radio modules and the multi-hop radio module so as to access a desired base station using the path indicated by the path selection information from the path control station. The control module more preferably integrates the plurality of radio modules and the multi-hop radio module so as to access at least one base station using the route indicated by the route selection information transmitted from the route control station. To control.

  Preferably, the route control station generates route selection information including at least a route for performing wireless communication by the multi-hop wireless system, and transmits the route selection information to a plurality of wireless devices.

  Preferably, the path control station performs the wireless communication by the first wireless system included in the plurality of wireless systems and the total number of standby traffic in the wireless communication network system when the wireless communication by the multi-hop wireless system is not used. A first minimum traffic number that is a minimum value of the number of standby traffics in a plurality of wireless devices when a plurality of wireless devices are switched to a first route for performing wireless communication by a multi-hop wireless system, and included in the plurality of wireless systems A second minimum traffic number that is a minimum value of the number of standby traffic in a plurality of wireless devices when the second route and the first route for performing wireless communication by the second wireless system are used simultaneously. And the calculated first and second minimum traffic and the total number of standby traffic calculated. Based on the Fick number, select the first path or the first and second paths, it generates and transmits a route selection information indicating the selected route to a plurality of wireless devices.

  Preferably, when the first minimum traffic number is smaller than the total waiting traffic number and the second minimum traffic number, the route control station generates route selection information indicating the first route and transmits the route selection information to the plurality of wireless devices. To do.

  Preferably, when the second minimum traffic number is smaller than the total waiting traffic number and the first minimum traffic number, the routing control station generates route selection information indicating the first and second routes used simultaneously. To multiple wireless devices.

  Preferably, the plurality of wireless systems have different wireless communication areas. The second route is a route for performing wireless communication by a wireless system having a relatively narrow wireless communication area among a plurality of wireless systems.

  Preferably, the plurality of wireless systems have different communication speeds. The second route is a route for performing wireless communication by a wireless system having a relatively high communication speed among a plurality of wireless systems.

  Preferably, the control means includes a selection means, an instruction means, and a route search means. The selecting means selects at least the multi-hop wireless system so that the number of standby traffic in the plurality of wireless devices is relatively reduced. The instructing unit instructs to search for a route for performing wireless communication by the multi-hop wireless system. The route search means searches for a route for performing wireless communication by the multi-hop wireless system in response to an instruction from the instruction means. Each of the plurality of wireless devices, when the multi-hop wireless system is selected by the selection unit, accesses at least one base station along the route searched by the route search unit.

  Preferably, the plurality of base stations include a wide area base station and a plurality of narrow area base stations. The wide area base station is a base station having the widest wireless communication area. The plurality of narrow area base stations are arranged in the radio communication area of the wide area base station, and each has a radio communication area that is narrower than the radio communication area of the wide area base station. The selection means and the instruction means are mounted on the wide area base station. The route search means includes a plurality of search means. The plurality of search means are installed in a plurality of wireless devices and a plurality of narrow area base stations, and each searches for a route that minimizes the number of standby traffic in the wireless apparatus or the narrow area base station. The instruction means instructs a plurality of search means to search for a route. Each of the plurality of search means, upon receiving an instruction from the instruction means, generates an initial value of the number of standby traffic in the wireless device or the narrow area base station in which the search means is installed and transmits the initial value to all search means other than itself. When an initial value is received from one search process and another search means other than itself, the received initial value is used to calculate the number of at least one standby traffic in the wireless device or narrow base station in which the self is mounted. At the same time, the first waiting traffic number which is the minimum waiting traffic number among the calculated at least one waiting traffic number is detected, and the detected first waiting traffic number is transmitted to all search means other than itself. When the first waiting traffic number is received from the second searching process and other searching means other than itself, the received first waiting traffic is received. And calculating the number of at least one waiting traffic in the wireless device or narrow base station on which the self is mounted using the number, and the second waiting time that is the minimum number of waiting traffic among the calculated at least one waiting traffic number The number of traffic is detected, and the minimum number of standby traffic in the wireless device or the narrow base station on which the self is mounted is updated by the detected second standby traffic, and the second standby traffic number is searched for all other than the self. And a third search process for repeatedly performing the update process to be transmitted to the means. Each of the plurality of wireless devices and the plurality of narrow base stations performs wireless communication by the multi-hop wireless system using a route having the minimum number of standby traffic.

  Preferably, the instructing unit transmits an upper limit value of the number of standby traffics to the plurality of radio apparatuses and the narrow area base station. Each of the plurality of searching means detects the first and second waiting traffic numbers from the waiting traffic number equal to or less than the upper limit value, and calculates at least one waiting traffic number calculated in the second and / or third searching process. When all of the above exceed the upper limit, transmission of the first and / or second waiting traffic number is stopped. Each of the plurality of wireless devices and the narrow area base station stops wireless communication by the multi-hop wireless system when the search means in itself stops transmitting the first and / or second waiting traffic numbers.

  Preferably, the instruction unit transmits a predetermined period for performing the first to third search processes to the plurality of radio apparatuses and the narrow area base station. Each of the plurality of search means stops the first to third search processes when the period for performing the route search reaches a certain period.

  Preferably, the fixed period is set to a relatively short period when the total number of the plurality of base stations and the plurality of wireless devices is relatively large, and the total number of the plurality of base stations and the plurality of wireless devices is relatively small When it is set to a relatively long period.

  Preferably, the instructing unit transmits the number of update processes to the plurality of radio apparatuses and the narrow area base station. Each of the plurality of search means repeatedly performs the update process until the number of updates reaches the number of update processes.

  In the wireless communication network system according to the present invention, at least one wireless system is selected from the plurality of wireless systems and the multi-hop wireless system so that the number of standby traffic is relatively small, and depends on the selected at least one wireless system. Access to a desired base station is performed using a path for performing wireless communication.

  Therefore, according to the present invention, a desired base station can be accessed with high efficiency.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a schematic diagram of a radio communication network system according to Embodiment 1 of the present invention. The wireless communication network system 100 includes wireless WAN (Wide Area Network) terminals 1 to 4, wireless LAN terminals 5 and 6, a wireless WAN base station 10, wireless LAN base stations 20 and 30, and a route control station 40. Prepare.

  The wireless LAN terminal 5 and the wireless LAN base station 20 exist in the wireless LAN cell 60, and the wireless LAN terminal 6 and the wireless LAN base station 30 exist in the wireless LAN cell 70. Then, the wireless LAN terminals 5 and 6 access the wireless LAN base stations 20 and 30 by the wireless LAN system, respectively.

  The wireless WAN terminals 1 to 4, the wireless LAN terminals 5 and 6, the wireless WAN base station 10, and the wireless LAN base stations 20 and 30 exist in the wireless WAN cell 80. Then, the wireless WAN terminals 1 to 4 access the wireless WAN base station 10 independently.

  The wireless WAN base station 10, the wireless LAN base stations 20 and 30, and the route control station 40 are connected to a network 50 such as the Internet by wired cables 41 to 44, respectively. The terminals 51 to 54 are composed of a personal computer, a server, and the like, and are connected to the network 50.

  Each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 periodically transmits a Hello packet including its own ID, and an adjacent terminal list including IDs of wireless LAN terminals or wireless WAN terminals adjacent to itself. And the traffic generation rate of the mobile station itself are transmitted to the wireless WAN base station 10 or the wireless LAN base stations 20 and 30.

  In addition, each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 includes a plurality of wireless systems and a multi-hop wireless system, as described later, and a plurality of equipped wireless terminals according to instructions from the route control station 40. A radio system and a multi-hop radio system are properly used or used at the same time to access a desired base station.

  The wireless WAN base station 10 or the wireless LAN base stations 20 and 30 receive the adjacent terminal list and the traffic generation rate from the wireless WAN terminals 1 to 4 or the wireless LAN terminals 5 and 6, and the received adjacent terminal list and the traffic generation rate. Is transmitted to the route control station 40 via the wired cables 41 to 44.

  The path control station 40 receives the adjacent terminal list and the traffic occurrence rate from the wireless WAN base station 10 or the wireless LAN base stations 20 and 30, and based on the received adjacent terminal list, the wireless WAN terminal in the wireless communication network system 100 1 to 4 and the topology of the wireless LAN terminals 5 and 6 are created. Then, the route control station 40 determines that each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 becomes a desired base station by a method described later based on the created topology and the received traffic occurrence rate. A route for access is selected, route selection information including the selected route is generated, and transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6.

  The wireless communication network system 100 has the following characteristics.

  (A) One or more wireless LAN base stations are uniformly distributed in an access network that is a communication area covered by the wireless WAN base station 10. Both wireless LAN base stations are accommodated in a common access network.

  (B) The wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 can communicate with the wireless WAN base station 10 and the wireless LAN base stations 20 and 30, and have a multihop inter-terminal communication function and multihop inter-terminal communication. To the wireless WAN base station 10 or the wireless LAN base stations 20 and 30.

  (C) The wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 simultaneously perform three types of communication: access to the wireless WAN base station 10, access to the wireless LAN base stations 20 and 30, and communication between multihop terminals. It can be implemented and has a function of branching traffic into these three types of communications.

  FIG. 2 is a schematic block diagram showing the configuration of the wireless WAN terminal 1 shown in FIG. The wireless WAN terminal 1 includes an antenna 11, wireless modules 12 to 14, a switching unit 15, a controller 16, an application processor 17, and a bus BS.

  The switching means 15, the controller 16, and the application processor 17 are connected to each other by a bus BS. The radio modules 12 to 14 are connected to the switching unit 15.

  The antenna 11 receives data from other wireless WAN terminals or wireless LAN terminals via the wireless communication space, and outputs the received data to at least one of the wireless modules 12 to 14. Data from at least one is transmitted to another wireless WAN terminal or wireless LAN terminal via the wireless communication space.

  Each of the wireless modules 12 to 14 is equipped with a different wireless system. More specifically, the wireless module 12 includes a wireless WAN system (IEEE802.16e), the wireless module 13 includes a wireless LAN system (IEEE802.11g or IEEE802.11j), and the wireless module 14 includes a plurality of wireless modules 14. Equipped with a multi-hop wireless system that performs wireless communication via the terminal.

  The wireless module 12 performs wireless communication with the wireless WAN base station 10 via the antenna 11 using the wireless WAN system. In this case, the wireless module 12 uses a frequency of 2 to 11 GHz, a transmission rate of about 15 Mbps, an OFDM (Orthogonal Frequency Division Multiplexing) modulation scheme, and a CSMA / CA (Carrier Sense Multiple Access Amplification Association Access Access scheme).

  The wireless module 13 performs wireless communication with the wireless LAN base station 20 or 30 via the antenna 11 using a wireless LAN system. In this case, the wireless module 13 uses a frequency of 2.4 GHz, a transmission rate of 54 Mbps, an OFDM modulation scheme, and a CSMA / CA access scheme.

  Further, the wireless module 14 uses a multi-hop wireless system to establish a wireless communication path with the wireless WAN base station 10 and the wireless LAN base stations 20 and 30 as a transmission destination, and the established wireless communication path Wireless communication with the transmission destination. In this case, the wireless module 14 uses a frequency of 2.4 GHz, a transmission rate of 11 Mbps, a DSSS (Direct Sequence Spread Spectrum) modulation scheme, and a CAMA / CA access scheme.

  As described above, the wireless modules 12 to 14 are equipped with different wireless systems, and transmit the packets received from the switching means 15 singly or simultaneously according to the control from the switching means 15 using the equipped wireless systems.

  The switching means 15 receives the route selection information from the controller 16 via the bus BS, and uses the route indicated by the received route selection information to select a desired base station (wireless WAN base station 10 and wireless LAN base station 20,. The wireless modules 12 to 14 are controlled in an integrated manner to access any one of 30). In this case, “integrated control” means that the wireless modules 12 to 14 are entirely controlled so that wireless communication is realized by at least one wireless module selected from the three wireless modules 12 to 14. To tell.

  Then, the switching unit 15 transmits the packet received from the application processor 17 to a wireless module (at least one wireless module of the wireless modules 12 to 14) that performs wireless communication using the route indicated by the route selection information.

  The controller 16 receives a Hello message from another wireless WAN terminal or another wireless LAN terminal, extracts an ID of another wireless WAN terminal or an ID of another wireless LAN terminal from the received Hello message, and extracts the extracted An adjacent terminal list including the IDs is created.

  In addition, the controller 16 acquires a traffic occurrence rate in the wireless WAN terminal 1.

  Furthermore, the controller 16 receives the route selection information from the route control station 40 and transmits the received route selection information to the switching means 15.

  The application processor 17 generates a packet and transmits the generated packet to the switching unit 15.

  Note that each of the wireless WAN terminals 2 to 4 and the wireless LAN terminals 5 and 6 shown in FIG. 1 has the same configuration as that of the wireless WAN terminal 1 shown in FIG.

  FIG. 3 is a schematic diagram showing a partial configuration of the wireless WAN base station 10 shown in FIG. The wireless WAN base station 10 is the same as the wireless WAN terminal 1 except for the wireless module 14 of the wireless WAN terminal 1 shown in FIG.

  In the wireless WAN base station 10, the wireless module 12 performs wireless communication with the wireless WAN terminals 1 to 4 using the wireless WAN system and transmits packets by the multihop wireless communication using the multihop wireless system to the wireless WAN terminals 1 to 4. 4, the wireless module 13 performs wireless communication with the wireless LAN terminals 5 and 6 using the wireless LAN system and receives packets from the wireless LAN terminals 5 and 6 by multihop wireless communication using the multihop wireless system. To do.

  Each of the wireless LAN base stations 20 and 30 shown in FIG. 1 has the same configuration as the wireless WAN base station 10 shown in FIG.

  In the wireless communication network system 100 shown in FIG. 1, each of the wireless WAN terminals 1 to 4, the wireless LAN terminals 5 and 6, the wireless WAN base station 10, and the wireless LAN base stations 20 and 30 includes a Hello message including its own ID. Generate and send periodically. Then, each of the wireless WAN terminals 1 to 4, the wireless LAN terminals 5 and 6, the wireless WAN base station 10, and the wireless LAN base stations 20 and 30 receives the Hello message from the adjacent terminal or base station, and the received Hello An ID of an adjacent terminal or base station is extracted from the message, and an adjacent terminal list including the extracted ID is created.

  In addition, each of the wireless WAN terminals 1 to 4, the wireless LAN terminals 5 and 6, the wireless WAN base station 10, and the wireless LAN base stations 20 and 30 calculate their own traffic occurrence rate.

  Then, the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 transmit the calculated traffic occurrence rate and the created adjacent terminal list to the wireless WAN base station 10 or the wireless LAN base stations 20 and 30. Further, the wireless WAN base station 10 controls the route of the adjacent terminal list and the traffic occurrence rate received from the wireless WAN terminals 1 to 4 and the adjacent terminal list and the traffic occurrence rate created by itself through the wired cables 41 and 44. Transmit to station 40. Further, the wireless LAN base stations 20 and 30 transmit the adjacent terminal list and traffic generation rate received from the wireless LAN terminals 5 and 6 and the adjacent terminal list and traffic generation rate created by the wireless LAN base station 20 and 30 via the wired cables 42 to 44. Transmit to the route control station 40.

  Then, the route control station 40 receives the adjacent terminal list and the traffic occurrence rate from the wireless WAN base station 10 and the wireless LAN base stations 20 and 30, and based on the received adjacent terminal list, the wireless WAN terminals 1 to 4 And the topology of the wireless LAN terminals 5 and 6 are recognized, and the number of standby traffic in the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 is minimized based on the recognized topology and the received traffic occurrence rate. A route is selected as described above, and route selection information indicating the selected route is generated. Then, the route control station 40 transmits the generated route selection information to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 via the wireless WAN base station 10.

  That is, in the present invention, when each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 accesses a desired base station, the route control station 40 is connected to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 5. 6 shows at least one of a wireless WAN system, a wireless LAN system, and a multi-hop wireless system so that the number of standby traffics in 6 is minimized, and shows a path for performing wireless communication by the selected at least one wireless system Route selection information is created and transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6.

  And as a case where the number of standby traffics in the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 becomes relatively small, the following two wireless communication methods may be used.

  (MTH1) A wireless communication system for performing wireless communication by switching direct communication between any one of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 and the wireless WAN base station 10 to multihop wireless communication.

  (MTH2) A wireless communication system that uses both direct communication between the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 and the wireless LAN base stations 20 and 30 and multi-hop wireless communication.

  Hereinafter, the effectiveness of the wireless communication systems MTH1 and MTH2 when any one of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 accesses a desired base station with high efficiency will be described.

  First, a mathematical model for verifying the effectiveness of the wireless communication schemes MTH1 and MTH2 will be described.

[Mathematical model]
In order to verify the effectiveness of the wireless communication systems MTH1 and MTH2, the following three routes were defined.

(R1) W-route The W-route is a route by direct communication between any one of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6, and the wireless WAN base station 10, and includes a single link.

(R2) L-route The L-route is a route by direct communication between any one of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6, and the wireless LAN base stations 20 and 30, and consists of a single link. .

(R3) Terminal cooperation access route The terminal cooperation access route is a communication route to a base station by multi-hop wireless communication between terminals, and a plurality of links are connected and configured. In the following, the terminal cooperation access route is also referred to as a “multi-hop wireless communication route”.

  The wireless communication network system 100 shown in FIG. 1 is composed of a large number of terminals, and the traffic at each terminal is considered to be sufficiently smaller than the traffic of the entire wireless communication network system 100.

  Therefore, the links constituting the routes R1 to R3 are regarded as an M / M / 1 queuing system, and the effectiveness of the wireless communication systems MTH1 and MTH2 is verified using the cost of each link.

  However, in the verification, protocol mechanisms such as mobility and retransmission of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 are not considered, and communication branching is not performed in multihop wireless communication.

  FIG. 4 is a conceptual diagram for explaining a single link and a connection link. According to the M / M / 1 queuing system, the data arrival interval is a Poisson process, and the data transfer time follows an exponential distribution.

In this case, it is assumed that the average data arrival rate at the terminal i, that is, the average traffic generation rate is F _i (Mbps). If the communication capacity between the terminal i and the terminal j is C _ij (Mbps), the average data transfer rate is C _ij , and the cost d _ij in this link is expressed by the following equation (in FIG. 4). (See (a)).

Expression (1) is a function obtained by multiplying the average communication delay time 1 / (C _ij −F _i ) of the link by the traffic F _i and is the number of traffic in the link. Therefore, in the present invention, the cost d _ij means “the number of traffic in the link”.

The cost d _ij increases when large traffic is generated on a link having a small communication capacity, and decreases when traffic is appropriately allocated according to the communication capacity.

  Next, the average communication delay time in a plurality of links connecting a single link (see FIG. 4B) is determined based on Burke's theorem (Non-patent Document 2) and Jackson's theorem (Non-patent Document 2). It is calculated as the sum of the average communication delay times. The traffic at each terminal is considered as the sum of the traffic that arrives after being transferred and the traffic that occurs within each terminal.

  If it does so, the cost of the path | route by connection of several links will be represented by following Formula.

  FIG. 5 is a conceptual diagram for explaining a branch link. The cost of each link when traffic is distributed (branched) from a terminal to a plurality of terminals and transferred is represented by the following equation (see FIG. 5).

_{However, p ij} is the rate at which traffic _{F i} are distributed from the terminal i to the terminal _{j, p ik} is the rate at which traffic _{F i} are distributed from the terminal i to the terminal _{k, p ix} is traffic _{F i} is This is the ratio of distribution from terminal i to terminal x.

The communication capacity C _ij in each link described above strongly depends on the radio wave characteristics. In the present invention, the communication capacity C _ij in each link is set by the following method.

(A) The communication capacity C _ij of each of the L-path and the W-path is represented by a fraction of the number of terminals in the wireless LAN cells 60 and 70 and the wireless WAN cell 80.

(B) The communication capacity C _ij of the route by multi-hop wireless communication is represented by 1 / (number of hops × number of multi-hop routes relayed in the same cell).

(C) When the sum of the coverage of the route by multi-hop wireless communication (the number of terminals x (area / terminal) plus the communication coverage) exceeds the coverage of the wireless WAN system, the communication capacity of the route by multi-hop wireless communication C _ij is represented by (number of hops × number of multi-hop routes relayed in the same cell) × 1 wireless WAN coverage / (sum of coverage of multi-hop routes).

  In order to evaluate the route by multi-hop wireless communication, the total cost G of the entire wireless communication network system 100 is obtained by the following equation using the cost of each link (= the number of standby traffic) used in route selection.

  In equation (4), N is the total number of links.

  The verification of the effectiveness of the wireless communication systems MTH1 and MTH2 using the mathematical model described above will be described.

[Verification using mathematical model]
In the verification of the effectiveness of the wireless communication systems MTH 1 and MTH 2, one wireless WAN base station 10, a plurality of wireless LAN base stations 20 and 30 uniformly distributed in the wireless WAN cell 80, and the wireless WAN cell 80 Consider a wireless communication network system 100 including wireless WAN terminals 1 to 4 and wireless LAN terminals 5 and 6 that are uniformly distributed.

  Each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 forms the above-described three routes R1 to R3 in the wireless communication network system 100 as follows.

  When each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 exist in the wireless LAN cells 60 and 70, the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 are connected to the wireless LAN base stations 20 and 30 to form an L-path.

  Further, when the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 do not exist in the wireless LAN cells 60 and 70, the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 connect to the wireless WAN base station 10 to form a W-path.

  Further, each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 is connected to an adjacent terminal capable of communicating using a wireless LAN system different from the L-path to form a multi-hop wireless communication path.

  Note that the traffic generated in the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 is the same.

  Then, the evaluation function in the wireless communication network system 100 is as follows.

However, D ^W is the sum of the cost of each W- pathway, D ^L is the sum of the cost of each L- pathway, D ^T is the sum of the cost of each multi-hop wireless communication path.

(Effectiveness of wireless communication method MTH1)
The case where the W-path is switched to the multi-hop wireless communication path is verified. FIG. 6 is a conceptual diagram showing switching from the W-path to the multi-hop wireless communication path. The multi-hop wireless communication path is configured by connecting the same number of wireless WAN terminals as the number of hops and one wireless LAN terminal according to the number of hops.

  Further, the traffic of the terminals constituting the multi-hop wireless communication path is transferred to the wireless LAN base stations 20 and 30 through the multi-hop wireless communication path. That is, as shown in FIG. 6, one multi-hop wireless communication path (wireless WAN terminal 2 -wireless WAN terminal 3 -wireless WAN terminal 4 -wireless LAN terminal 5) has the same number of wireless WAN terminals 2 as the number of hops in the path. Formed by switching ˜4 W-paths to multi-hop wireless communication paths.

  In this case, the costs of the wireless WAN system, the wireless LAN system, and the multi-hop wireless system are expressed by the following equations (6) to (8), respectively.

However, ^{U W} is the number of wireless WAN terminal, ^{u x} is the number of paths of a multi-hop wireless communication path, ^{C W} is the communication capacity of W- path, Hop a multi-hop wireless communication hops is a number, U ^L is the number of wireless LAN terminals, C ^L is the communication capacity of L- path, C ^T is the communication capacity of each link constituting a multi-hop wireless communication path, F is , Traffic of each terminal.

  7 and 8 are first and second diagrams showing the relationship between the cost and the number of multi-hop wireless communication paths, respectively. 7 and 8, the horizontal axis represents the number of multi-hop wireless communication paths, and the vertical axis represents the cost. Curves k1 to k5 shown in FIG. 7 indicate cases where the number of hops is 1 hop, 2 hops, 4 hops, 8 hops, and 16 hops, respectively. Further, a curve k6 shown in FIG. 8 shows a case of multi-hop wireless communication, and a curve k7 shows a case of L-path wireless communication. A curve k8 indicates a case of W-path wireless communication, and a curve k9 indicates a total of multi-hop wireless communication, L-path wireless communication, and W-path wireless communication.

  Note that the relationship between the cost indicated by the curves k1 to k9 and the number of multi-hop wireless communication paths is that the total number of terminals in the wireless communication network system 100 is 1000, the radius of the wireless WAN cell 80 is 1000 m, and the maximum communication of the wireless WAN system is The capacity is 15 Mbps, the radius of the wireless LAN cells 60 and 70 is 100 m, the maximum communication capacity of the wireless LAN system is 54 Mbps, the communicable distance of multihop wireless communication is 100 m, the maximum communication capacity of multihop wireless communication is 54 Mbps, It is a simulation result when traffic is 0.01 Mbps.

  In any number of hops, the cost of the link decreases as the number of multi-hop wireless communication paths increases (see FIG. 7). Therefore, it is effective to perform wireless communication by switching the W-path to the multi-hop wireless communication path.

  This is because the number of terminals accommodated in the wireless WAN cell 80 is larger than the number of terminals accommodated in the wireless LAN cells 60 and 70 (10002: 1002 = 100: 1). This is because the communication capacity and the communication capacity of the multi-hop wireless communication path are significantly reduced.

  However, when the number of multi-hop wireless communication paths with a large number of hops increases, the evaluation function starts to increase. This is because when the number of multi-hop wireless communication paths with a large number of hops increases, radio resources for performing multi-hop wireless communication are depleted and the communication delay time of the multi-hop wireless communication path increases (see FIG. 8).

  That is, traffic is distributed from a path with a small communication capacity (W-path) to a path with a large communication capacity (multi-hop radio communication path) by the multi-hop wireless communication path, and the cost of the link is improved. Therefore, the cost of the link can be optimized by the multi-hop wireless communication path (the number of paths and the number of hops), and the effectiveness of the wireless communication method MTH1 that performs wireless communication by switching the W-path to the multi-hop wireless communication path is high. That is, the wireless LAN base stations 20 and 30 are accessed using a multi-hop wireless communication path having a relatively large communication capacity compared to accessing the wireless WAN base station 10 using a W-path having a relatively small communication capacity. The access to the wireless WAN base station 10 via the wireless LAN base stations 20 and 30 can relatively reduce the link cost (= number of link communications), thereby realizing highly efficient wireless communication.

(Effectiveness of wireless communication method MTH2)
First, a case where the W-route and the L-route are used simultaneously will be described. The evaluation function in this case is the sum of the cost of the W-path and the cost of the L-path. The cost of the ^W -path is D ^W = F ^W / (C ^W −F ^W ), and the cost of the ^L -path is D ^L = F ^L / (C ^L −F ^L ). However, ^{F W} is a traffic volume to be distributed to the W- path, ^{F L} is a traffic volume to be distributed to the L- path. Therefore, F ^W + F ^L = F.

When D ^W and D ^L are functions of traffic F ^W and F ^L , respectively, since D ^W and ^DL are convex functions, the optimal solutions f ^W and f ^L of the respective functions are expressed by the following two expressions: Meet.

From equations (9) and (10), the optimum solutions f ^W and f ^L are expressed by equations (11) and (12), respectively.

FIG. 9 is a diagram showing the relationship between the optimal solutions f ^W and f ^L calculated by the equations (11) and (12) and traffic. In FIG. 9, the horizontal axis represents traffic, and the vertical axis represents optimum solutions f ^W and f ^L. Curve k10 represents the relationship between the optimal solution ^{f L} and traffic, straight k11 represents the relationship between the optimal solution ^{f W} and traffic.

As can be seen from FIG. 9, when the traffic volume is small, it is advantageous to use only the L-path having a large communication capacity, the traffic volume increases, and a certain threshold value (F ≧ C ^W − (C ^W C ^{If L} ) 1/2) is exceeded, it is advantageous to use the L-path and the W-path with a small communication capacity at the same time.

  FIG. 10 is a diagram showing a usage pattern when two routes are used simultaneously. FIG. 10A illustrates a usage mode in which the wireless WAN terminal 1 simultaneously uses the W-path for accessing the wireless WAN base station 10 and the L path for accessing the wireless LAN base station 30, and FIG. ) Includes an L-path for the wireless WAN terminal 6 to access the wireless LAN base station 30 and a multi-hop wireless communication path for accessing the wireless LAN base station 20 via the wireless WAN terminals 2 to 4 and the wireless LAN terminal 5. The usage form used simultaneously is shown.

  As described with reference to FIG. 9, there are cases where it is advantageous to use the W-route and the L-route at the same time. Therefore, the usage mode MOD1 shown in FIG. 10A and the configuration shown in FIG. The effectiveness is compared with the usage mode MOD2 shown in FIG.

  In usage mode MOD2, the multi-hop wireless communication path includes one wireless LAN terminal 6 that distributes traffic, (number of hops-1) wireless WAN terminals 2 to 4, and wireless LAN terminal 6 that is a traffic transmission source. A wireless LAN terminal 5 (having a destination L-path) existing in different wireless LAN cells 60 is connected (see FIG. 10B).

  In order to determine only the effect of simultaneous use in the multi-hop wireless communication path, the multi-hop wireless communication path does not transfer the traffic of the wireless WAN terminals 2 to 4 in the path.

  When the L-path and the W-path are used at the same time, the costs of the W-path, the L-path, and the multi-hop wireless communication path are expressed by Expression (13) to Expression (15), respectively.

  Further, when the L-path and the multi-hop wireless communication path are used at the same time, the costs of the W-path, the L-path, and the multi-hop wireless communication path are expressed by Expression (16) to Expression (18), respectively. .

However, p ^W is the ratio that is allocated to traffic W- route, p ^L is the ratio that is allocated to traffic L- route, p ^T is the rate at which traffic is distributed to multi-hop wireless communication path is there. Therefore, p ^W + p ^L = 1 or p ^T + p ^L = 1.

  FIG. 11 is a diagram illustrating the cost when two routes are used simultaneously. In FIG. 11, the horizontal axis represents the number of wireless LAN connection terminals when two routes are used simultaneously, and the vertical axis represents the cost. A straight line k12 indicates a case where the W-route and the L-route are simultaneously used. A straight line k13 to k16 and a curve k17 indicate the number of hops in the simultaneous use of the L-route and the multi-hop wireless communication route. The case of 1 hop, 2 hops, 4 hops, 8 hops and 16 hops is shown.

  In addition, FIG. 11 distributes 0.0009 of the traffic amount of the L-path (the distribution ratio capable of reducing the cost in the simultaneous use of the L-path and the W-path) to the W-path or the multi-hop wireless communication path. Shows cost fluctuations. The traffic volume was 5.2 Mbps for half of all wireless LAN terminals, and 0.01 Mbps for other terminals.

  From the results shown in FIG. 11, in any number of hops, it is possible to obtain a lower cost by using the L-path and the multi-hop wireless communication path simultaneously than using the W-path and the L-path simultaneously. .

  FIG. 12 is another diagram showing the cost when two routes are used simultaneously. In FIG. 12, the horizontal axis represents the number of wireless LAN connection terminals when two routes are used simultaneously, and the vertical axis represents cost. The straight lines k18 to k20 and the curves k21 and k22 indicate the cases where the number of hops is 1 hop, 2 hops, 4 hops, 8 hops, and 16 hops in the simultaneous use of the L-path and the multi-hop wireless communication path, respectively. Show.

  FIG. 12 shows the cost fluctuation when 0.95 of the L-path traffic is distributed to the multi-hop wireless communication path.

  From the results shown in FIG. 12, when the number of hops increases in the multi-hop wireless communication path, the multi-hop delay increases and the cost starts to increase (see curves k21 and k22). Further, as described above, there is an optimum amount for traffic distribution according to the traffic amount.

  Therefore, when using the L-path and the multi-hop wireless communication path at the same time, it is important to control traffic distribution and optimize the cost in the multi-hop wireless communication path.

  From the above, when two paths are used simultaneously, it is effective to use the L-path and the multi-hop wireless communication path simultaneously. That is, the effectiveness of the wireless communication method MTH2 was verified.

  As described above, since the effectiveness of the wireless communication systems MTH1 and MTH2 has been verified, in the present invention, each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 uses the wireless communication systems MTH1 and MTH2. To access the desired base station.

Therefore, the routing control station 40 uses the multi-hop wireless communication for each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 based on the topology of the wireless communication network system 100 and the wireless communication status (traffic occurrence rate). The total cost G ⁰ (= total number of standby traffic) of the entire wireless communication network system 100 when there is not, and each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 from the W-path to the path by multi-hop wireless communication The minimum value G1 (= first minimum traffic number) of the total cost G ¹ (Hop, u ^x ) of the entire wireless communication network system 100 according to the number of hops and the number of routes when switching, the L-path and the multi-hop Depending on the number of hops, the number of routes, and the traffic distribution ratio when using wireless communication routes simultaneously Total cost ^G 2 of the entire line communication network system ^{100 (Hop, u x, p} ) the minimum value ^G 2 (= minimum traffic speed of the second) of computing a.

Then, the path control station 40 compares the calculated total cost G ⁰ and the minimum values G ¹ and G ² with each other. When G ¹ <G ⁰ and G ¹ <G ² , multi-hop wireless communication is performed. Route selection information indicating a route for performing the transmission is generated and transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6. In this case, the communication form of wireless communication is the communication form shown in (b) of FIG. Further, when G ² <G ⁰ and G ² <G ¹ , the route control station 40 is used simultaneously with route selection information indicating a route for performing the L-route and multi-hop wireless communication. The traffic distribution ratios for the two routes are generated and transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6. In this case, the communication form of wireless communication is the communication form shown in (b) of FIG.

The path control station 40 calculates G ⁰ as the sum of D ^W , D ^L , and D ^T calculated by substituting u ^x = 0 into the above-described equations (6) to (8). Further, the path control station 40 calculates G ¹ as the minimum value of the sum total of D ^W , D ^L , and D ^T calculated by substituting u ^x ≠ 0 into Equations (6) to (8). Furthermore, path control station 40, ^D W that is calculated by the equation ^{(16) ~ (18),} D L, and calculates the ^{G 2} as the minimum value of the sum of ^{D T.}

  FIG. 13 is a flowchart for explaining the operation of wireless communication in the wireless communication network system 100. In the flowchart shown in FIG. 13, a case where the wireless WAN terminal 2 or the wireless LAN terminal 6 accesses the wireless WAN base station 10 will be described as an example.

  When a series of operations is started, the path control station 40 uses the wireless WAN base station 10 or the wireless LAN base stations 20 and 30 to determine the adjacent terminal lists and traffic occurrence rates of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6. (Step S1).

Then, the route control station 40 calculates the total cost G ^{0 of the} entire wireless communication network system 100 when the multi-hop wireless communication is not used by the above-described method (step S2).

Thereafter, the route control station 40 uses the above-described method to switch the W-route to the route for performing multi-hop wireless communication, and the total cost G1 of the entire wireless communication network system 100 according to the number of hops and the number of routes. The minimum value G ¹ of Hop, u ^x ) is calculated (step S3).

Subsequently, the route control station 40 uses the above-described method to change the wireless communication network system according to the number of hops, the number of routes, and the traffic distribution ratio when the L-route and the route for performing multi-hop wireless communication are used simultaneously. The minimum value G ² of the total cost G ² (Hop, u ^x , p) of the entire 100 is calculated (step S4).

Then, path control station ^40, G 1 ^{<G 0 and,} it is determined whether or not ^G 1 <G ² (step ^{S5), G 1 <G 0} , ^and G 1 ^{<G 2} is not satisfied Then, it is further determined whether or not G ² <G ⁰ and G ² <G ¹ (step S6).

When it is determined in step S6 that G ² <G ⁰ and G ² <G ¹ , the path control station 40 selects a path indicating an L-path and a path for performing multi-hop wireless communication. Information and a traffic distribution ratio are transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 via the wireless WAN base station 10 (step S7).

  The controllers 16 of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 receive from the wireless WAN base station 10 route selection information indicating a route for performing L-route and multihop wireless communication, and a traffic distribution ratio. Then, the received route selection information and traffic distribution ratio are transmitted to the switching means 15.

  The switching means 15 receives the route selection information and the traffic distribution ratio from the controller 16, and based on the received traffic distribution ratio, the traffic on the L-path indicated by the route selection information and the path for performing multi-hop wireless communication And the wireless modules 12 to 14 are integratedly controlled to perform wireless communication using the distributed traffic. More specifically, the switching unit 15 controls the wireless module 12 to stop wireless communication, controls the wireless module 13 to perform wireless communication through the L-path, and performs multi-hop wireless communication. The wireless module 14 is controlled.

  Thereby, each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 accesses the wireless WAN base station 10 by simultaneously using the L-path and the path for performing multi-hop wireless communication.

On the other hand, when it is determined in step S6 that G ² <G ⁰ and G ² <G ¹ are not satisfied, the series of operations ends.

Further, when it is determined in step S5 that G ¹ <G ⁰ and G ¹ <G ² , the path control station 40 switches the path for performing multi-hop wireless communication to be used by switching from the W-path. And the generated route selection information is transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 via the wireless WAN base station 10 (step S8).

  The controllers 16 of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 receive route selection information indicating a route for performing multihop wireless communication to be used by switching from the W-route from the wireless WAN base station 10, The received route selection information is transmitted to the switching means 15.

  The switching unit 15 receives the route selection information from the controller 16 and integrates the wireless modules 12 to 14 so as to perform wireless communication using a route for performing multihop wireless communication indicated by the received route selection information. To control. More specifically, the switching unit 15 controls the wireless modules 12 and 13 so as to stop the wireless communication, and controls the wireless module 14 so as to perform the multi-hop wireless communication.

  Accordingly, each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 switches the wireless communication using the W-path to the multi-hop wireless communication and accesses the wireless WAN base station 10.

  When it is determined “NO” in step S6, or after step S7 or after step S8, the series of operations ends.

  In the flowchart shown in FIG. 13, the minimum value G1 is the minimum value of the total cost in the above-described wireless communication method MTH1, and the minimum value G2 is the minimum value of the total cost in the above-described wireless communication method MTH2. The wireless communication methods MTH1 and MTH2 are communication methods that have a lower total cost than wireless communication using the W-path.

  Therefore, when each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 accesses a desired base station, the desired base station is accessed by the wireless communication method MTH1 or MTH2 rather than accessing the desired base station by direct communication. In order to confirm that the total cost is smaller when accessing the network, the determinations shown in steps S5 and S6 are made.

  Further, in steps S7 and S8, the route control station 40 transmits route information for performing wireless communication to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 by the wireless communication methods MTH2 and MTH1, respectively. Even if the wireless WAN terminal 2 or the like cannot be directly accessed because the wireless communication to the wireless WAN base station 10 is congested, the wireless WAN terminal 2 and the like are connected via the wireless WAN terminals 3 and 4 and the wireless LAN terminal 5. By the multi-hop wireless communication, the wireless WAN base station 10 can be accessed with high efficiency.

  Then, according to the flowchart shown in FIG. 13, when each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 accesses a desired base station, it accesses the desired base station using the wireless communication methods MTH1 and MTH2. Therefore, the route control station 40 in the present invention is connected between the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6, and between the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 and the wireless WAN base station 10. Wireless WAN system, wireless LAN, and wireless LAN terminals 1 to 4 and wireless LAN terminals 5 and 6 and wireless LAN base stations 20 and 30 so that costs (= number of standby traffic) are relatively reduced. Selecting at least one radio system from the system and the multi-hop radio system and selecting the selected at least one radio system To the wireless WAN terminal 1-4 and the wireless LAN terminal 5,6 and generates routing information indicating a route for performing wireless communication by beam.

  In this case, the route control station 40 preferably generates route selection information indicating a route for performing at least wireless communication by the multi-hop wireless system, and transmits the route selection information to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6. .

  In step S7, the route control station 40 performs wireless communication using both the wireless LAN system and the multi-hop wireless system, which have a relatively small wireless communication area, among the wireless WAN system and the wireless LAN system. Route selection information indicating a route to be performed is generated and transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6.

  Furthermore, in step S7, the path control station 40 performs wireless communication using both the wireless LAN system having a relatively high communication speed and the multi-hop wireless system among the wireless WAN system and the wireless LAN system. Route selection information indicating a route for the transmission is generated and transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6.

  Further, in step S8, the route control station 40 switches a route for performing wireless communication by switching a wireless WAN system having a relatively wide wireless communication area from the wireless WAN system and the wireless LAN system to a multi-hop wireless system. The route selection information shown is generated and transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6.

  Further, in step S8, the route control station 40 indicates a route for performing wireless communication by switching a wireless WAN system having a relatively low communication speed from the wireless WAN system and the wireless LAN system to a multi-hop wireless system. Route selection information is generated and transmitted to the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6.

  In the above description, the wireless WAN system and the wireless LAN system are shown as wireless systems having different communication areas. However, in the present invention, in addition to the wireless WAN system and the wireless LAN system, a wireless MAN (Metropolitan Area Network) system and a wireless system are used. A PAN (Personal Area Network) system may be used, and two or more wireless systems selected from a wireless WAN system, a wireless MAN system, a wireless LAN system, and a wireless MAN system may be used.

  In the present invention, each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 may include a wireless module that performs wireless communication in accordance with the standards of IEEE 802.15x and IEEE 802.20.

  Furthermore, in the above description, the route control station 40 has been described as being independent of the wireless WAN base station 10 and the wireless LAN base stations 20 and 30. However, in the present invention, the route control station 40 is not limited to this. The wireless WAN base station 10 or the wireless LAN base stations 20 and 30 may be incorporated.

  Furthermore, in the present invention, the operation of each step of the flowchart shown in FIG. 13 may be shared by the route control station 40 and the wireless WAN terminals 1 to 4, and the operation of each step of the flowchart shown in FIG. The control station 40 and the wireless LAN terminals 5 and 6 may be shared.

  In the present invention, the wireless WAN base station 10 and the wireless LAN base stations 20 and 30 constitute “a plurality of base stations”.

  The wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 constitute a “plurality of wireless devices”.

  Further, the wireless modules 12 and 13 constitute “a plurality of wireless modules”.

  Further, the wireless module 14 constitutes a “multi-hop wireless module”.

  Further, the switching means 15 constitutes a “control module”.

  Further, the L-route constitutes a “route for performing wireless communication by a wireless LAN system having a relatively narrow wireless communication area”.

  Furthermore, the L-path constitutes a “path for performing wireless communication by a wireless LAN system having a relatively high communication speed”.

  Further, the wireless WAN system, the wireless MAN system, the wireless LAN system, and the wireless PAN system constitute “a plurality of wireless systems”.

  Further, the route control station 40 is configured to use a plurality of wireless systems and multi-hop wireless systems so that the number of standby traffic in the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 (= a plurality of wireless devices) is relatively reduced. At least one wireless system is selected, a route for performing wireless communication by the selected at least one wireless system is determined, and at least one base station (wireless WAN base station 10 and wireless LAN base is determined by the determined route) A control means for controlling a plurality of wireless devices so as to access any one of the stations 20 and 30) is mounted.

[Embodiment 2]
FIG. 14 is a schematic diagram of a wireless communication network system according to the second embodiment. The wireless communication network system 100A according to the second embodiment deletes the route control station 40 and the wired cable 44 of the wireless communication network system 100 shown in FIG. 1, and performs wireless WAN terminals 1 to 4, wireless LAN terminals 5 and 6, wireless WAN. The base station 10 and the wireless LAN base stations 20 and 30 are replaced with the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, the wireless WAN base station 10A, and the wireless LAN base stations 20A and 30A, respectively. Is the same as the wireless communication network system 100.

  The wireless LAN terminals 5A and 6A access the wireless LAN base stations 20A and 30A by the wireless LAN system, respectively. The wireless WAN terminals 1A to 4A independently access the wireless WAN base station 10A by the wireless WAN system.

  The wireless WAN base station 10A and the wireless LAN base stations 20A and 30A are connected to a network 50 such as the Internet by wired cables 41 to 43, respectively.

  Each of the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A calculates the minimum cost of the route in itself within a certain period in accordance with an instruction from the wireless WAN base station 10A, and wirelessly calculates the calculated minimum cost. Flooding is performed in the communication network system 100A. Note that “flooding” refers to transmitting packets or the like to all of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, the wireless WAN base station 10A, and the wireless LAN base stations 20A and 30A of the wireless communication network system 100A. Say.

  The wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A perform the same functions as the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6, respectively.

  The wireless WAN base station 10A receives the adjacent terminal list and the traffic generation rate from the wireless LAN base stations 20A and 30A via the wired cable 41, the network 50, and the wired cables 42 and 43, and receives the received adjacent terminal list and traffic generation. Based on the rate, topologies of the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A in the wireless communication network system 100A are created. Then, the wireless WAN base station 10A is a wireless device that minimizes the costs in the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A by a method described later based on the created topology and the received traffic occurrence rate. A communication method is selected, and the selected wireless communication method is output to the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A.

  When the wireless WAN base station 10A selects at least a wireless communication system based on a multihop wireless communication system as a wireless communication system that minimizes the cost in the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A, An instruction is transmitted to the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A so as to search for a route for performing wireless communication by the communication system.

  The wireless LAN base stations 20A and 30A receive the adjacent terminal list and the traffic generation rate from the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A, and the received adjacent terminal list and the traffic generation rate are respectively transmitted to the wired cables 42, 43, and transmitted to the wireless WAN base station 10A via the network 50 and the wired cable 41. In addition, the wireless LAN base stations 20A and 30A have the same functions as the wireless LAN base stations 20A and 30.

  The wireless communication network system 100A has the same characteristics as the wireless communication network system 100 shown in FIG.

  FIG. 15 is a schematic block diagram showing the configuration of the wireless WAN terminal 1A shown in FIG. The wireless WAN terminal 1 </ b> A is obtained by adding a search module 18 to the wireless WAN terminal 1 shown in FIG. 2, and is otherwise the same as the wireless WAN terminal 1.

  The search module 18 is connected to the switching means 15, the controller 16, and the application processor 17 by the bus BS and is also connected to the antenna 11.

  The search module 18 receives a route search instruction from the wireless WAN base station 10A via the antenna 11, and performs wireless communication by the multi-hop wireless system according to the received route search instruction by a method described later. Search for a route.

  Each of the wireless WAN terminals 2A to 4A and the wireless LAN terminals 5A and 6A has the same configuration as that of the wireless WAN terminal 1A shown in FIG.

  FIG. 16 is a schematic diagram illustrating a partial configuration of the wireless WAN base station 10A illustrated in FIG. The wireless WAN base station 10A is the same as the wireless WAN base station 10 except that the controller 16 of the wireless WAN base station 10 shown in FIG.

The controller 16A calculates G ⁰ , G ¹ , and G ² by the same method as the path control station 40 in the first embodiment. Then, the controller 16A ^is, G 1 ^{<G 0 and,} it is determined whether or not ^{G 1 <G 2, G 1} <G 0 ^and, when G 1 ^{<G 2} are not ^{satisfied, G} 2 <G It is further determined whether ⁰ and G ² <G ¹ or not.

When it is determined that G ² <G ⁰ and G ² <G ¹ , the controller 16A selects the wireless LAN system and the multi-hop wireless system, and indicates that the wireless LAN system and the multi-hop wireless system are selected. The packet PKT_MT1 is transmitted to the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A via the switching unit 15, the wireless module 12, and the antenna 11.

Further, when the controller 16A determines that G ¹ <G ⁰ and G ¹ <G ² , the controller 16A selects the multi-hop radio system and switches the packet PKT_MT1 indicating that the multi-hop radio system has been selected to the switching unit 15. Then, the data is transmitted to the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A via the wireless module 12 and the antenna 11.

  Furthermore, when the controller 16A selects at least the multi-hop wireless system, the controller 16A sends a route search instruction for instructing a route search for wireless communication by the multi-hop wireless system to the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A. And transmitted to the wireless LAN base stations 20A and 30A.

  FIG. 17 is a schematic diagram showing the configuration of the wireless LAN base station 20A shown in FIG. The wireless LAN base station 20 </ b> A is obtained by adding a search module 18 to the wireless WAN base station 10 shown in FIG. 3, and the other configuration is the same as that of the wireless WAN base station 10.

  The search module 18 performs the same function as the search module 18 of the wireless WAN terminal 1A shown in FIG.

  The wireless LAN base station 30A has the same configuration as that of the wireless LAN base station 20A shown in FIG.

  In the first embodiment, in the wireless communication network system 100, each of the wireless WAN terminals 1 to 4 and the wireless LAN terminals 5 and 6 performs wireless communication by one of the wireless communication systems MTH1 and MTH2. Thus, it has been explained that a desired base station (at least one of the wireless WAN base station 10 and the wireless LAN base stations 20 and 30) can be accessed with high efficiency.

  Therefore, also in the second embodiment, each of the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A performs wireless communication by one of the wireless communication systems MTH1 and MTH2. That is, each of the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A performs wireless communication by at least a multi-hop wireless system.

  FIG. 18 is a diagram illustrating the relationship between communication delay time and throughput in the case of 8 hops. In FIG. 18, the vertical axis represents the communication delay time, and the horizontal axis represents the throughput. Curves k23 to k28 show the relationship between the communication delay time and the throughput when the number of paths is 10, 30, 60, 70, 82, and 98, respectively.

  From the results shown in FIG. 18, it can be seen that in multi-hop wireless communication with the number of hops being “8”, the communication delay time decreases and the throughput improves as the number of routes increases. The link cost in the multi-hop wireless communication with the number of hops “8” decreases as shown by a curve k4 in FIG. Therefore, a path configuration with a low link cost (= 8 hop multi-hop) improves the throughput while suppressing the communication delay time of the entire wireless communication network system 100A.

  As described above, the wireless communication by the multi-hop wireless system is effective for suppressing the communication delay time and improving the throughput in the entire wireless communication network system 100A.

  Accordingly, a method for searching for a route when each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A performs wireless communication by the multihop wireless system will be described.

  In searching for a route in wireless communication by a multi-hop wireless system, a plurality of wireless devices involved in wireless communication by the multi-hop wireless system are used in order to suppress communication delay time of the entire wireless communication network system 100A and improve throughput. A route is searched so that the sum of a plurality of route costs in the device (= a plurality of wireless devices selected from the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A) is minimized. The The route cost is the number of traffic on the route for each wireless device to perform wireless communication with an adjacent wireless device.

  Each route cost is obtained by the equation (1). This equation (1) is an equation for obtaining a route cost in a steady state that is independent of time (measurement time is infinite). Therefore, in the second embodiment, in order to perform wireless communication using a multihop wireless system so as to adapt to a changing wireless communication environment, a route for performing wireless communication using a multihop wireless system is set to a small time interval Δt. Search in.

  The number of waiting traffic for each link is represented by the following two equations as a function of time Δt.

Note that P _n (t + 2Δt) is the probability that the number of waiting traffics in the period [t + Δt, t + 2Δt] is n, and P _n (t + Δt) is the probability that the number of waiting traffics in the period [t, t + Δt] is n. Yes, F (t + Δt) is the traffic arrival rate in the period [t, t + Δt], and C (t + Δt) is the communication rate in the period [t, t + Δt].

  Then, when the formula (19) and the formula (20) are expanded, the following formula is obtained.

  From equation (21), it can be seen that the expected value of the number of waiting traffic on the link is obtained from the ratio of the traffic arrival rate to the transmission rate in the period [t, t + Δt] and the number of waiting traffic on the link in the period [t, t + Δt]. . That is, the link cost is obtained by the following equation.

  However, Q (t + Δt) is an average value of the number of standby traffics on the link in the period [t, t + Δt].

  The controller 16A of the wireless WAN base station 10A instructs the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A to generate and flood the initial value of the path cost.

Then, assuming that each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A is a terminal d, the search module 18 of the terminal d responds to an instruction from the wireless WAN base station 10A. The route cost D _d ^d = 0 addressed to itself is generated as an initial value, and the generated route cost D _d ^d = 0 is transmitted to the nearby terminal s.

Upon receiving the route cost D _d ^d = 0 from the terminal d, the search module 18 of the terminal s uses the received route cost D _d ^d = 0 to minimize the cost among the route costs of the terminal s according to the following equation: The route cost D _d ^s is calculated.

Here, N (s) is a set of neighboring terminals of the terminal and the base station in the wireless communication network system 100A, and d _sm is a link cost between the terminal s and the neighboring terminal m. Further, since Expression (23) is an expression derived based on the number of standby traffics at the constant time Δt shown in Expression (19) and Expression (20), the path cost D _d ^s in Expression (23) is a steady state. It is not the route cost in, but the route cost in the short period Δt.

When the search module 18 of the terminal s receives the initial value D _d ^d = 0, the search module 18 calculates d _sm using the equation (22), substitutes the calculated d _sm into the equation (23), and sets the initial value D _d. ^The path cost D _d ^s is calculated by substituting ^d = 0 into D _d ^m in the equation (23). Then, the search module 18 of the terminal s floods the minimum path cost among at least one path cost D _d ^s calculated using the equation (23).

Also, the search module 18 of the terminal s, the initial value _D ^d After calculating the route cost _D ^{d s} with d = 0, when receiving the route cost _D ^{d s} from the vicinity terminal m, route cost _{D d} with the received Substituting ^s into equation (23), the path cost D _d ^s is newly calculated. Then, the search module 18 of the terminal s floods the minimum path cost among at least one path cost D _d ^s newly calculated using the equation (23).

That is, the search module 18 of the terminal s repeatedly calculates at least one path cost D _d ^{s according} to the equation (23) until the search time reaches a certain period ΔT, and the minimum is calculated from the calculated at least one path cost D _d ^s. The route cost is selected and flooded repeatedly. As a result, the minimum route cost is repeatedly updated. Accordingly, the search module 18 of the terminal s repeatedly updates the minimum route cost until the search time reaches a certain period Δt.

  Then, a route having a minimum route cost when a certain period ΔT has elapsed is determined as a route for performing wireless communication by the multi-hop wireless system.

  The search module 18 of each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A uses the above-described method to perform a wireless communication by the multihop wireless system for a certain period ΔT. Explore.

  In searching for a route for performing wireless communication by the multi-hop wireless system, the controller 16A of the wireless WAN base station 10A includes the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A. The wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the upper limit value of the route cost when searching for a route for performing wireless communication by the multi-hop wireless system, the minimum number of times of updating the route cost, and the fixed period ΔT It transmits to the search module 18 of wireless LAN base station 20A, 30A.

  The upper limit value of the route cost is used by the search modules 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A to discard the route cost exceeding the upper limit value. The fixed period ΔT is a value set according to the number of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A in the wireless communication network system 100A. When the number of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A is relatively large, the fixed period ΔT is set to a relatively short value, and the wireless WAN terminal 1A When the number of wireless LAN terminals 5A and 6A and wireless LAN base stations 20A and 30A is relatively small, the predetermined period ΔT is set to a relatively long value.

  The wireless WAN base station 10A detects the power on / off of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A, thereby providing a wireless WAN existing in the wireless WAN cell 80. The number of terminals 1A to 4A, wireless LAN terminals 5A and 6A, and wireless LAN base stations 20A and 30A is detected. Therefore, the wireless WAN base station 10A can easily set the fixed period ΔT according to the number of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A.

  FIG. 19 is a flowchart for explaining an operation of selecting a wireless system in which the number of standby traffic is relatively small in the wireless communication network system 100A. The flowchart shown in FIG. 9 is the same as the flowchart shown in FIG. 13 except that steps S7 and S8 in the flowchart shown in FIG. 13 are replaced with steps S7A and S8A, respectively.

When the controller 16A of the wireless WAN base station 10A executes steps S1 to S6 described in the first embodiment and determines that G ² <G ⁰ and G ² <G ¹ in step S6, The LAN system and the multi-hop wireless system are selected (step S7A), and the selection of the wireless LAN system and the multi-hop wireless system is performed via the wireless module 12 through the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN. Transmit to the base stations 20A and 30A.

If the controller 16A of the wireless WAN base station 10A determines that G ¹ <G ⁰ and G ¹ <G ² in step S5, the controller 16A selects a multi-hop wireless system (step S8A), and multi-hop wireless. The fact that the system has been selected is transmitted to the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20AA and 30A via the wireless module 12. Thereby, a series of operation | movement is complete | finished.

As described above, in the second embodiment, the wireless WAN base station 10A includes the topology of the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A and the wireless WAN terminals 1A to 4A and the wireless LA terminals 5A and 6A. Based on the traffic occurrence rate, the total costs G ⁰ , G ¹ , G ² are calculated, and based on the calculated total costs G ⁰ , G ¹ , G ² , the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A, At least a multi-hop wireless system is selected as a wireless system in which the number of standby traffic in 6A is relatively small.

FIG. 20 is a flowchart for explaining an operation of searching for a route for performing wireless communication by the multihop wireless system. When a series of operation is started, the controller 16A of the wireless WAN base station 10A generates the initial value _D ^d d = 0 of the path cost, instruction DIR for Furradingu the initial value _D ^d d = 0 which is the product Is transmitted to the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A (step S11).

In each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A, the search module 18 receives the instruction DIR via the antenna 11, and responds to the received instruction DIR. The initial value D _d ^d = 0 of the path cost is generated, and the generated initial value D _d ^d = 0 is flooded via the antenna 11 (step S12).

After that, the search module 18 of the terminal or base station (each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A) that has received the initial value D _d ^d = 0 Substituting _d ^d = 0 into equation (23) to calculate at least one path cost D _d ^s 1 of the terminal or base station on which it is mounted, and the minimum is calculated from the calculated at least one path cost D _d ^s 1 The route cost D _d ^s 1_min is detected (step S13).

Then, the search module 18 of the terminal or base station (the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A) that received the initial value D _d ^d = 0 detects the minimum The path cost D _d ^{s 1 —} min is flooded via the antenna 11 (step S14).

  Thereafter, the search module 18 of each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A sets the elapsed time t in each terminal or each base station to t = 0 (step S15), it is determined whether or not the elapsed time t has reached a certain time Δt or more (step S16).

When each of the search modules 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A determines in step S16 that the elapsed time t has reached a predetermined time Δt or more. The link cost d _ij is recalculated using the equation (22) (step S17), and the route time t is set to t = 0 (step S18). In this way, the search module 18 of each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A has a traffic arrival rate F ( t + Δt), transmission rate C (t + Δt), and number of waiting traffic Q (t + Δt) are used to recalculate the link cost d _ij . Thereafter, the series of operations proceeds to step S20.

On the other hand, each search module 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A determines that the elapsed time t has not reached the predetermined time Δt or more in step S16. Then, it is further determined whether or not the route cost D _d ^s has been received (step S19). When it is determined in step S19 that the route cost D _d ^s has not been received, the series of operations proceeds to step S23.

On the other hand, when it is determined in step S19 that the path cost D _d ^s has been received, or after step S18, each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A. The search module 18 calculates at least one path cost D _d ^s 2 by substituting the minimum path cost D _d ^s 1 — min received from another terminal or another base station into D _d ^m in Equation (23), from at least one route cost _D ^{d s} 2 and the operation for detecting the minimum path cost _D ^d s _{2_min} (step S20).

Thereafter, each of the search modules 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A can detect the terminal or base on which the wireless LAN terminals 1A to 4A are mounted by the detected minimum path cost D _d ^s 2_min. The minimum path cost in the station is updated (step S21), and the updated minimum path cost D _d ^s 2_min is flooded via the antenna 11 (step S22).

  When it is determined in step S19 that the route cost has not been received, or after step S22, the search modules 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A, respectively. Determines whether the search time has reached a certain period ΔT or more (step S23). The fixed period ΔT is a time that defines the route search time in the entire wireless communication network system 100A.

  When it is determined in step S23 that the search time has not reached the fixed period ΔT or more, the series of operations returns to step S16, and in step S23, until it is determined that the search time has reached the fixed period ΔT or more. The above-described steps S16 to S23 are repeatedly executed.

  When it is determined in step S23 that the search time has reached the predetermined period ΔT or more, the search modules 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A are The search of the route is stopped, and the plurality of search modules 18 in the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A are connected to each terminal and each base station when the search is stopped. A route having the minimum link cost is determined as a route for performing wireless communication by the multi-hop wireless system (step S24). Thereby, a series of operation | movement is complete | finished.

When steps S20 and S21 shown in FIG. 20 are executed once, the search module 18 of each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A has a minimum path cost D. _d ^s 2_min1 (a kind of D _d ^s 2_min) is detected, and the minimum path cost in the terminal or base station on which it is installed is updated by the detected minimum path cost D _d ^s 2_min1.

This minimum path cost D _d ^{s 2 —} min1 is a minimum path cost reflecting the minimum path cost D _d ^{s 1 —} min1 (minimum path cost detected in step S13) in another terminal or another base station. is there. Therefore, the path having the minimum path cost _D ^d s _{2_min1} is a path associated with the path having a minimum path cost _D ^d s _{1_min1} in another terminal or another base station.

For example, when the search module 18 of the wireless WAN terminal 3A illustrated in FIG. 14 receives the minimum path cost D _d ^s 1_min1 from the search module 18 of the wireless WAN terminal 2A, the received minimum path cost D _d ^s 1_min1 is reflected. and calculates at least one route cost _D ^{d s} 2 by the equation (23), detecting a minimum path cost _D ^d s _{2_min1} from route cost _D ^{d s} 2 that its operation.

Then, the search module 18 of the wireless WAN terminal 3A is (see step S13) minimum path cost _D before detecting the ^d s ^2_min1, and detects the minimum route cost _D ^d s _{1_min1,} minimum path in step S20 When the cost D _d ^s 2_min1 is detected, the minimum path cost in the wireless WAN terminal 3A is updated with the detected minimum path cost D _d ^s 2_min1.

Therefore, the route having the minimum route cost D _d ^s 2_min1 in the wireless WAN terminal 3A is a route associated with the route having the minimum route cost D _d ^s 1_min1 in the wireless WAN terminal 2A.

When steps S20 and S21 shown in FIG. 20 are executed twice, each search module 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A The cost D _d ^{s 2 —} min 2 (a kind of D _d ^{s 2 —} min) is detected, and the minimum path cost in the terminal or base station in which the terminal is mounted is updated by the detected minimum path cost D _d ^s 2 — min 2.

The minimum path cost D _d ^s 2_min2 is different from other terminals or other base stations that transmitted the minimum path cost D _d ^s 1_min1 received when steps S20 and S21 are executed for the first time. Is the minimum path cost reflecting the minimum path cost D _d ^{s 2 —} min1 received from the terminal or other base station. Therefore, the path having the minimum path cost _D ^d s _{2_min2} is a path associated with a plurality of paths having the lowest path cost _D ^d s _{2_min1} In another plurality of terminals or a plurality of other base stations.

For example, when the search module 18 of the wireless WAN terminal 3A illustrated in FIG. 14 receives the minimum path cost D _d ^s 2_min1 from the search module 18 of the wireless WAN terminal 4A, the received minimum path cost D _d ^s 2_min1 is reflected. and calculates at least one route cost _D ^{d s} 2 by the equation (23), detecting a minimum path cost _D ^d s _{2_min2} from route cost _D ^{d s} 2 that its operation.

Then, the search module 18 of the wireless WAN terminal 3A is (see first step S20) minimum path cost _D ^d s _{2_min2} before detecting the, and detects the minimum route cost _D ^d s _{2_min1,} the second time When the minimum path cost D _d ^{s 2 —} min 2 is detected in step S 20, the minimum path cost in the wireless WAN terminal 3 A is updated with the detected minimum path cost D _d ^s 2 — min 2.

Therefore, the route having the minimum route cost D _d ^s 2_min2 in the wireless WAN terminal 3A is a route associated with the route having the minimum route cost D _d ^s 2_min1 in the wireless WAN terminal 4A. Then, the route having the minimum route cost _D ^d s _{2_min1,} as described above, since the path associated with the path having a minimum path cost _D ^d s _{1_min1} the wireless WAN terminal 2A, after all, the wireless WAN terminal path having a minimum path cost _D ^d s _{2_min2} in 3A is a path having a minimum path cost _D ^d s _{1_min1} the wireless WAN terminal 2A, and a path having a minimum path cost _D ^d s _{2_min1} the wireless WAN terminal 4A These routes are associated with the two routes.

  Then, each of the search modules 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A repeatedly executes steps S20 and S21, thereby increasing the number of other terminals or others. The minimum path cost associated with the minimum path cost at the base station is detected at the terminal or base station in which the base station is mounted. In step S23, when the search time reaches a certain time ΔT or more, the minimum path cost associated with the minimum path cost in many other terminals or other base stations at that time is determined by each terminal or each base station. Is detected. As a result, a route for performing wireless communication by the multi-hop wireless system is determined so that the sum of route costs in the wireless communication network system 100A is minimized (see step S24).

  When each of the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A is determined, wireless communication by the multi-hop wireless system is performed along the determined path. Communicate and access the desired base station.

  In steps S13 and S20 of the flowchart shown in FIG. 20, the search modules 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A are transmitted from the wireless WAN base station 10A. The minimum route cost may be detected by discarding the route cost exceeding the upper limit value of the received route cost.

  The upper limit value of the route cost may be set according to the state of wireless communication in the wireless communication network system 100A, or set for the purpose of the wireless WAN base station 10A controlling wireless communication in the wireless communication network system 100A. May be.

  When the upper limit value of the route cost is set according to the state of the wireless communication in the wireless communication network system 100A, the wireless WAN base station 10A determines the upper limit value of the route cost as follows and the wireless WAN terminals 1A to 4A The wireless LAN terminals 5A and 6A and the wireless LAN base stations 20A and 30A are transmitted.

  As described above, since the wireless WAN base station 10A knows the number of traffics in the wireless WAN terminals 1A to 4A and the wireless LAN terminals 5A and 6A, it can grasp the traffic number in the wireless communication network system 100A. Accordingly, the controller 16A of the wireless WAN base station 10A, for example, sets a relatively large upper limit value when the number of traffic in the wireless communication network system 100A is relatively large, and sets the wireless WAN terminals 1A to 4A and wireless LAN terminals. 5A, 6A and wireless LAN base stations 20A, 30A, if the number of traffic in the wireless communication network system 100A is relatively small, a relatively small upper limit value is set and the wireless WAN terminals 1A-4A, wireless LAN The data is transmitted to the terminals 5A and 6A and the wireless LAN base stations 20A and 30A.

  When the upper limit value of the path cost is set for the purpose of the wireless WAN base station 10A controlling the wireless communication in the wireless communication network system 100A, the controller 16A of the wireless WAN base station 10A determines the cost of the entire wireless communication network system 100A. The upper limit value of the route cost is determined so that becomes the target value and transmitted to the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A.

  In this way, the wireless WAN base station 10A is detected by discarding the route cost exceeding the upper limit value of the route cost (that is, selecting the route cost lower than the upper limit value of the route cost) and detecting the minimum route cost. Can control wireless communication by the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A existing in the wireless WAN cell 80.

  When the minimum route cost is detected by discarding the route cost exceeding the upper limit value of the route cost, at least one route cost calculated in steps S13 and S20 shown in FIG. 20 may all exceed the upper limit value. In this case, each of the search modules 18 of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A cannot detect the minimum path cost, and therefore steps S14 and S22 shown in FIG. Do not execute.

  Accordingly, a terminal or base station that has not been able to detect the minimum path cost cannot search for a path for performing wireless communication by the multihop wireless system, and therefore does not perform wireless communication by the multihop wireless system. As a result, the wireless communication network system 100A does not perform wireless communication using the multi-hop wireless system. That is, since there is no route having the minimum route cost that satisfies the route cost set by the wireless WAN base station 10A, each of the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A. Does not perform wireless communication by a multi-hop wireless system.

  For example, in FIG. 14, when the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminal 5A, and the wireless LAN base station 20A are searching for a route for performing wireless communication by the multihop wireless system, the wireless WAN terminal 4A When there is no route cost equal to or lower than the upper limit value of the route cost, the wireless WAN terminal 4A does not perform wireless communication using the multihop wireless system.

  The wireless WAN terminals 2A and 3A, the wireless LAN terminal 5A, and the wireless LAN base station 20A except the wireless WAN terminal 4A perform wireless communication by the multihop wireless system, but the wireless WAN terminal 4A performs wireless communication by the multihop wireless system. Therefore, after all, the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminal 5A, and the wireless LAN base station 20A do not perform wireless communication by the multi-hop wireless system. That is, in this case, the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminal 5A, and the wireless LAN base station 20A cannot perform wireless communication by the multihop wireless system requested by the wireless WAN base station 10A.

  Further, in step S23 of the flowchart shown in FIG. 20, when the update count of the minimum route cost does not reach the update count transmitted from the wireless WAN base station 10A, steps S16 to S23 are repeatedly executed, and the minimum route cost is determined. When the number of cost updates reaches the number of updates transmitted from the wireless WAN base station 10A, the process may proceed to step S24.

  As described above, even when the wireless WAN base station 10A sets the update count of the minimum path cost in each of the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A, The wireless WAN base station 10A can control wireless communication by the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base stations 20A and 30A that exist in the wireless WAN cell 80.

  As described above, the plurality of search modules 18 in the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A express the minimum path cost in each terminal or each base station using the equation (23 ) As needed to search for a route for performing wireless communication by the multi-hop wireless system so that the route cost in the entire wireless communication network system 100A becomes relatively small. Each of the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A performs wireless communication by the multi-hop wireless system according to the searched route. Therefore, each of the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A can access a desired base station with high efficiency.

  Further, according to the equation (23), the wireless LAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A each calculate the minimum path cost and perform wireless communication by the multi-hop wireless system. By determining a route to be performed, a route for performing wireless communication by the multihop wireless system can be determined while avoiding a congested route in the wireless communication network system 100A. This is because if the route is crowded, the communication capacity C is reduced and the route cost is increased, so that it is not selected as the route having the minimum route cost in each terminal or each base station. As a result, the throughput of the entire wireless communication network system 100A can be improved.

  Further, according to the equation (23), the wireless LAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A each calculate a minimum path cost and perform wireless communication by the multi-hop wireless system. By determining the route to be performed, it is possible to determine a route for performing wireless communication by the multi-hop wireless system while avoiding a route having a poor radio wave environment. This is because if the radio wave environment is deteriorated, the communication capacity is reduced and the route cost is increased, so that each terminal or each base station is not selected as a route having the minimum route cost. As a result, it is possible to perform wireless communication using the multi-hop wireless system by selecting a route having a favorable radio wave environment.

  Further, as described above, the wireless WAN base station 10A determines the upper limit value of the route cost, the minimum number of times of update of the route cost, and the fixed period ΔT as the wireless WAN terminals 1A to 4A, the wireless LAN terminals 5A and 6A, and the wireless LAN base. Since the wireless communication in the wireless communication network system 100A is controlled by transmitting to the stations 20A and 30A, the method for searching for a route for performing wireless communication by the multihop wireless system described above is particularly a wireless communication network performing cognitive radio. This is a method suitable for searching for a route for performing multi-hop wireless communication in the system.

  Furthermore, in the present invention, the route searching method described above may be applied to a mesh type wireless communication network system. In this case, the access point serves as the wireless WAN base station 10A.

  Furthermore, the route search method described above can be generally applied to a wireless communication network system including a control device that controls wireless communication and a plurality of wireless devices that perform wireless communication according to control by the control device.

  The controller 16A of the wireless WAN base station 10A and the search modules 18 of the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A constitute “control means”.

  Further, the controller 16A that selects at least the multi-hop wireless communication system in accordance with the flowchart shown in FIG. 19 constitutes “selecting means”.

  Furthermore, the controller 16A that transmits an instruction to the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A and the wireless LAN base stations 20A, 30A according to step S11 shown in FIG. 20 constitutes “instruction means”.

  Further, the plurality of search modules 18 in the wireless WAN terminals 2A, 3A, 4A, the wireless LAN terminals 5A, 6A, and the wireless LAN base stations 20A, 30A constitute “route search means” or “plural search means”.

  Further, the wireless WAN base station 10A constitutes a “wide area base station”, and the wireless LAN base stations 20A and 30A constitute “a plurality of narrow area base stations”.

  Furthermore, the process shown in step S13 shown in FIG. 20 constitutes a “first search process”, and the process of executing step S20 shown in FIG. 20 for the first time constitutes a “second search process”. The process of repeatedly executing step S20 shown in FIG. 20 a plurality of times after the second time constitutes a “third search process”.

  Others are the same as in the first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a wireless communication network system capable of accessing a desired base station with high efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of the radio | wireless communication network system by Embodiment 1 of this invention. It is a schematic block diagram which shows the structure of the wireless WAN terminal shown in FIG. It is the schematic which shows the structure of a part of radio | wireless WAN base station shown in FIG. It is a conceptual diagram for demonstrating a single link and a connection link. It is a conceptual diagram for demonstrating a branch link. It is a conceptual diagram which shows switching from a W-path | route to a multihop radio | wireless communication path | route. It is a 1st figure which shows the relationship between cost and the number of multihop radio | wireless communication paths. It is a 2nd figure which shows the relationship between cost and the number of multihop radio | wireless communication paths. It is a figure which shows the relationship between the optimal solution calculated by Formula (11), (12), and traffic. It is a figure which shows the utilization form in the case of using two paths | routes simultaneously. It is a figure which shows the cost at the time of using two paths | routes simultaneously. It is another figure which shows the cost at the time of using two paths | routes simultaneously. It is a flowchart for demonstrating operation | movement of the radio | wireless communication in a radio | wireless communication network system. FIG. 3 is a schematic diagram of a wireless communication network system according to a second embodiment. It is a schematic block diagram which shows the structure of the wireless WAN terminal shown in FIG. It is the schematic which shows the structure of a part of radio | wireless WAN base station shown in FIG. It is the schematic which shows the structure of the wireless LAN base station shown in FIG. It is a figure which shows the relationship between the communication delay time in the case of 8 hops, and a throughput. 15 is a flowchart for explaining an operation of selecting a wireless system in which the number of standby traffic is relatively small in the wireless communication network system shown in FIG. It is a flowchart for demonstrating the operation | movement which searches the path | route which performs radio | wireless communication by a multihop radio | wireless system.

Explanation of symbols

  1-4, 1A-4A wireless WAN terminal, 5, 5A, 6, 6A wireless LAN terminal, 10, 10A wireless WAN base station, 11 antenna, 12-14 wireless module, 15 switching means, 16, 16A controller, 17 application Processor, 18 Search module, 20, 20A, 30, 30A Wireless LAN base station, 40 Route control station, 41-44 Wired cable, 50 network, 51-54 terminal, 60, 70 Wireless LAN cell, 80 Wireless WAN cell, 100 , 100A Wireless communication network system.

Claims (14)

A plurality of base stations that are equipped with a plurality of different radio systems, and that perform radio communication using the radio systems equipped with each,
A plurality of radio devices each accessing at least one base station of the plurality of base stations using at least one radio system selected from the plurality of radio systems and a multi-hop radio system;
At least one wireless system is selected from the plurality of wireless systems and the multi-hop wireless system so that the number of standby traffic in the plurality of wireless devices is relatively small, and wireless communication by the selected at least one wireless system Control means for controlling the plurality of wireless devices so as to access the at least one base station according to the determined path .
The number of standby traffic is the reciprocal of the subtraction result obtained by subtracting the average occurrence rate of traffic in the one wireless device from the communication capacity in the link between one wireless device and the wireless device adjacent to the one wireless device. A wireless communication network system consisting of multiplication results obtained by multiplying the average incidence rate . The control means is mounted, further comprising a route control station that generates route selection information for selecting a route determined by the control means and transmits the route selection information to the plurality of wireless devices,
Each of the plurality of wireless devices is
A plurality of radio modules provided corresponding to the plurality of base stations, and equipped with the different radio systems and accessing the corresponding base stations via a path for performing radio communication by the radio systems equipped with the radio systems. When,
A multi-hop wireless module for accessing any of the plurality of base stations via a path for realizing wireless communication by a multi-hop wireless system;
A control module that integrally controls the plurality of radio modules and the multi-hop radio module to access a desired base station using a path indicated by path selection information from the path control station;
The control module integrates the plurality of radio modules and the multi-hop radio module to access the at least one base station using a route indicated by the route selection information transmitted from the route control station. The wireless communication network system according to claim 1, wherein the wireless communication network system is controlled.   The wireless communication network system according to claim 2, wherein the route control station generates route selection information including at least a route for performing wireless communication by the multi-hop wireless system, and transmits the route selection information to the plurality of wireless devices.   The routing control station performs wireless communication by the first wireless system included in the plurality of wireless systems and the total number of standby traffic in the wireless communication network system when wireless communication by the multi-hop wireless system is not used. A first minimum traffic number that is a minimum value of the number of standby traffic in the plurality of wireless devices when the route is switched to a first route for performing wireless communication by the multi-hop wireless system, and the plurality of wireless devices A second value that is a minimum value of the number of standby traffic in the plurality of wireless devices when the second route for performing wireless communication by the second wireless system included in the system and the first route are simultaneously used; The minimum traffic number is calculated, and the calculated total waiting traffic number and the calculated traffic number are calculated. Based on the first and second minimum traffic numbers, the first route or the first and second routes are selected, and route selection information indicating the selected route is generated to generate the plurality of The wireless communication network system according to claim 2 or 3, wherein the wireless communication network system transmits to a wireless device.   When the first minimum traffic number is smaller than the total waiting traffic number and the second minimum traffic number, the route control station generates route selection information indicating the first route and generates the plurality of radios. The wireless communication network system according to claim 4, wherein the wireless communication network system transmits to a device.   When the second minimum traffic number is smaller than the total waiting traffic number and the first minimum traffic number, the route control station stores route selection information indicating the first and second routes used simultaneously. The wireless communication network system according to claim 4, wherein the wireless communication network system is generated and transmitted to the plurality of wireless devices. The plurality of wireless systems have different wireless communication areas,
The wireless communication network system according to claim 6, wherein the second route is a route for performing wireless communication by a wireless system having a relatively narrow wireless communication area among the plurality of wireless systems. The plurality of wireless systems have different communication speeds,
The wireless communication network system according to claim 6, wherein the second route is a route for performing wireless communication by a wireless system having a relatively high communication speed among the plurality of wireless systems. The control means includes
Selection means for selecting at least the multi-hop wireless system so that the number of standby traffic in the plurality of wireless devices is relatively small;
Instruction means for instructing a search for a route for performing wireless communication by the multi-hop wireless system;
Route search means for searching for a route for performing wireless communication by the multi-hop wireless system in response to an instruction from the instruction means;
2. Each of the plurality of wireless devices, when the multi-hop wireless system is selected by the selection unit, accesses the at least one base station along a route searched by the route search unit. The wireless communication network system described. The plurality of base stations are
A wide area base station with the widest wireless communication area,
A plurality of narrow area base stations arranged in a radio communication area of the wide area base station, each having a radio communication area narrower than the radio communication area of the wide area base station,
The selection means and the instruction means are mounted on the wide area base station,
The route search means is mounted on the plurality of wireless devices and the plurality of narrow area base stations, and each of the plurality of search means searches for a route that minimizes the number of standby traffic in the wireless apparatus or the narrow area base station. Including
The instruction means instructs the plurality of search means to search for the route;
Each of the plurality of search means, upon receiving the instruction from the instruction means, generates an initial value of the number of standby traffic in the wireless device or the narrow area base station in which the search means is mounted, to all search means other than itself When the initial value is received from the first search process to be transmitted and other search means other than itself, at least one standby traffic in the wireless device or the narrow base station on which the self is mounted using the received initial value The number is calculated, and the first waiting traffic number which is the minimum waiting traffic number among the calculated at least one waiting traffic number is detected, and the detected first waiting traffic number is searched for all other than self. When the second search processing to be transmitted to the means and the first waiting traffic number from other search means other than the self are received, the received The number of standby traffic is calculated using at least one standby traffic number in the wireless device or the narrow base station on which the self is mounted using the number of standby traffic of 1, and is the minimum number of standby traffic among the calculated at least one standby traffic number The second standby traffic number is detected, the minimum standby traffic number in the wireless device or the narrow base station on which the mobile station is mounted is updated by the detected second standby traffic, and the second standby traffic number is updated. A third search process for repeatedly performing an update process to be transmitted to all search means other than
The wireless communication network system according to claim 9, wherein each of the plurality of wireless devices and the plurality of narrow base stations performs wireless communication by the multi-hop wireless system using a path having the minimum number of standby traffic. . The instructing means transmits the upper limit value of the waiting traffic number to the plurality of wireless devices and the narrow area base station,
Each of the plurality of search means detects at least one of the first and second standby traffic numbers from the number of standby traffic numbers less than or equal to the upper limit value, and is calculated in the second and / or third search processing. When all of the waiting traffic numbers exceed the upper limit, the transmission of the first and / or second waiting traffic number is stopped,
Each of the plurality of wireless devices and the narrow base station stops wireless communication by the multi-hop wireless system when search means in itself stops transmitting the first and / or second waiting traffic numbers. The wireless communication network system according to claim 10. The instructing means transmits a predetermined period for performing the first to third search processes to the plurality of radio apparatuses and the narrow area base station,
12. The wireless communication network according to claim 10, wherein each of the plurality of search means stops the first to third search processes when a period for performing a route search reaches the predetermined period. system.   The fixed period is set to a relatively short period when the total number of the plurality of base stations and the plurality of radio apparatuses is relatively large, and the total number of the plurality of base stations and the plurality of radio apparatuses is relatively The wireless communication network system according to claim 12, wherein the wireless communication network system is set to a relatively long period when the number is small. The instructing means transmits the number of times of the update process to the plurality of wireless devices and the narrow area base station,
14. The wireless communication network system according to claim 10, wherein each of the plurality of search units repeatedly performs the update process until an update count reaches the update process count.

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