JP2009159457A - Ad hoc communication system, communication method in the same, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption in each radio terminal for forming an ad hoc network when there are a plurality of communication paths relaying a packet, and to extend operation time in the entire ad hoc communication system. <P>SOLUTION: In the ad hoc communication system, a first terminal unit communicating with a radio terminal for forming an ad hoc network by radio sets the plurality of communication paths for transferring packets between the first terminal unit and a second one for communicating with one of the radio terminals by radio, collects information on the situation of the propagation of electric waves from at least one radio terminal for composing a communication path, turns on the radio terminals, prepares a schedule including an operation instruction for turning off the radio terminals for composing other communication paths based on information on the propagation range of the radio signal, and distributes the schedule to the radio terminal to be operated according to the operation instruction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ad hoc communication system, a communication method in an ad hoc communication system, and a computer program.

  In an ad hoc communication system, a plurality of wireless terminals forming an ad hoc network exchange their path information between these wireless terminals. Packets from the source wireless terminal are sequentially transferred using the other wireless terminal as an ad hoc relay device, and sent to the destination wireless terminal. It is desired to reduce power consumption of each wireless terminal and realize power saving in the entire network.

  Conventionally, as a technique for reducing the power consumption of communication terminals in an ad hoc network, a communication method in which a plurality of communication terminals enter a sleep state when one of the plurality of communication terminals transmits a first notification signal is known. (See Patent Document 1).

  As a technology to prevent the network connection time from being shortened due to a shortage of the storage battery of the master unit, when the slave unit can exchange data with the master unit, the transfer rate measured using the test signal and each A connection method of an ad hoc network system is also known in which a parent device collects the remaining amount of a storage battery of a child device and newly selects a true parent device based on the collected information (see Patent Document 2). ).

There has also been proposed a communication device including a control unit that switches a mode of a communication unit between a mode in which communication is performed while guaranteeing QoS and a mode in which communication is performed while performing power saving in an ad hoc mode (Patent Document 3). reference).
JP 2005-151476 A Japanese Patent Laid-Open No. 10-145276 JP 2007-124249 A

  In an ad hoc communication system, a plurality of different communication paths may be generated between a wireless terminal that is an information transmission source and a wireless terminal that is an information transmission destination. Although the packet is transferred according to any one of the communication paths, the wireless terminal as a node on the other communication path remains in a state where the transmission operation and the reception operation are performed.

  Since a plurality of ad hoc relay apparatuses forming an ad hoc network have a relay function, it is necessary to always operate the system and keep the entire system in an operating state. For this reason, these ad hoc relay apparatuses have a problem that their power consumption cannot be suppressed.

  Therefore, in view of the above problems, the present invention makes it possible to reduce power consumption of individual ad hoc relay devices that form an ad hoc network when there are a plurality of communication paths that relay packets in an ad hoc network. It is an object of the present invention to provide an ad hoc communication system, a communication method in an ad hoc communication system, and a computer program that can extend the operation time of the entire system.

  In order to solve such a problem, according to one aspect of the present invention, a first wireless communication is performed between a plurality of wireless terminals forming an ad hoc network and any one of these wireless terminals. A first terminal device and a second terminal device that performs wireless communication between any one of the wireless terminals forming the ad hoc network, and each wireless terminal wirelessly transmits and receives data to and from a wireless reception unit that receives wireless signals. A wireless transmission unit that wirelessly transmits route information indicating a plurality of wireless terminals capable of transmitting and information on a radio wave propagation state, and a first control unit that controls a transmission operation of the wireless transmission unit, the first terminal device Is configured to transmit a packet between the first terminal device and the second terminal device based on path information of each wireless terminal received by the wireless transmitting / receiving unit. Based on the information on the radio wave propagation status sent from each wireless terminal, the wireless terminal that configures any one of these communication paths is turned on or off And creating a schedule including an operation command with a content to turn off or turn on a wireless terminal constituting another communication path of the plurality of communication paths, and delivering the schedule to each of the wireless terminals. A second control unit that commands the radio transmission / reception unit, wherein the first control unit of each radio terminal is based on the operation command included in the schedule received via the radio reception unit. An ad hoc communication system is provided in which the transmission operation is suspended or activated.

  According to another aspect of the present invention, a first terminal device that performs wireless communication with any wireless terminal that forms an ad hoc network forms the first terminal device and the ad hoc network. A step of setting a plurality of communication paths for transferring packets to and from a second terminal device that performs wireless communication with any one of the wireless terminals, and the first terminal device is one of these communication paths Collecting information on radio wave propagation status from one or more wireless terminals constituting one communication path, and the first terminal device turns on one or more wireless terminals constituting one of the communication paths. And a schedule including an operation command with a content to turn off a wireless terminal constituting another communication path of the plurality of communication paths based on the information on the radio wave propagation status Providing a communication method in an ad hoc communication system, comprising: a step of distributing the schedule to a wireless terminal that the first terminal device operates according to the operation command. Is done.

  According to another aspect of the present invention, a first terminal device that performs wireless communication with any wireless terminal that forms an ad hoc network forms the first terminal device and the ad hoc network. A step of setting a plurality of communication paths for transferring packets to and from a second terminal device that performs wireless communication with any one of the wireless terminals, and the first terminal device is one of these communication paths Collecting information on radio wave propagation status from one or more wireless terminals constituting one communication path, and the first terminal device turns on one or more wireless terminals constituting one of the communication paths. And a schedule including an operation command with a content to turn off a wireless terminal constituting another communication path of the plurality of communication paths based on the information on the radio wave propagation status And causing the first terminal device to execute a step of distributing the schedule to a wireless terminal that operates in accordance with the operation command, on a computer mounted on the first terminal device. A featured computer program is provided.

  According to the present invention, in an ad hoc network, it is possible to reduce power consumption when individual wireless terminals operate, to extend the operation time of each wireless terminal, and to extend the operation time of the entire ad hoc communication system. Will be able to.

  Hereinafter, an ad hoc communication system, a communication method in an ad hoc communication system, and a computer program according to embodiments of the present invention will be described with reference to the drawings. In the drawings, the same portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a diagram showing an arrangement example in an area of a plurality of ad hoc relay devices constituting an ad hoc communication system according to an embodiment of the present invention. The ad hoc communication system according to the present embodiment is a transmission source terminal device 1 that is a transmission source of information and has a function of performing switching control of a packet transfer route, and a transmission that is a transmission destination of information from the transmission source terminal device 1 A plurality of ad hoc intervening between the destination terminal device 2 and the source terminal device 1 and the destination terminal device 2 respectively, and sequentially transferring packets from the source terminal device 1 and transmitting them to the destination terminal device 2 Relay devices 3, 4, 5, 6, 7, 8, 9 and 10 are provided.

  The ad hoc relay apparatuses 3 to 10 are all wireless terminals of the ad hoc communication system according to the present embodiment. The transmission source terminal device 1 is a first terminal device, and the transmission destination terminal device 2 is a second terminal device. The transmission source terminal device 1, the transmission destination terminal device 2, and the ad hoc relay devices 3 to 10 can all perform wireless communication using a wireless LAN, and an ad hoc network is formed by the ad hoc relay devices 3 to 10. ing.

  At a certain time, the ad hoc relay device 3 is located where it can communicate directly with the transmission source terminal device 1. The ad hoc relay device 4 is located where it can directly communicate with the ad hoc relay device 3, the ad hoc relay device 5 is located where it can communicate directly with the ad hoc relay device 4, and the ad hoc relay device 6 is located in the ad hoc relay device 5. The ad hoc relay device 7 is located where it can directly communicate with the ad hoc relay device 6 and the destination terminal device 2. These ad hoc relay apparatuses 3, 4, 5, 6 and 7 form a first communication path R1.

  At the same time, the ad hoc relay device 8 is located where it can communicate directly with the ad hoc relay device 3, the ad hoc relay device 9 is located where it can communicate directly with the ad hoc relay device 8, and the ad hoc relay device 10 It is located where it can communicate directly with the relay device 9. These ad hoc relay apparatuses 3, 8, 9, 10 and 7 form a second communication path R2. The ad hoc relay device 3 can directly communicate with both the ad hoc relay devices 4 and 8 and the transmission source terminal device 1, and the ad hoc relay device 7 can communicate with both the ad hoc relay devices 6 and 10 and the transmission destination terminal device 2. Can communicate directly with each other.

  In the ad hoc communication system according to the present embodiment, these ad hoc relay apparatuses 3 to 10 are used so as to remain at the same position for a certain period of time.

  The transmission source terminal device 1 is a terminal device having a wireless LAN communication function, and for example, a personal computer is used. FIG. 2 is a schematic configuration diagram of hardware of the transmission source terminal device 1. The transmission source terminal device 1 includes a wireless LAN communication unit (wireless transmission / reception unit) 11 that transmits and receives a radio signal in a high frequency band based on a communication procedure corresponding to a standard such as IEEE 802.11b / g, and an external peripheral device (not shown). An input / output unit (I / O) 12 for exchanging data between them, a CPU (central processing unit) 13 for performing calculations, and a storage device 14 for storing programs and data. Further, the transmission source terminal device 1 generates a GPS receiver 23 that outputs position information of its own terminal from positioning data of a GPS signal, a wireless LAN communication unit 11, an input / output unit 12, a CPU 13, a storage device 14, and a GPS. And a power supply 24 for supplying power to the receiver 23.

  The wireless LAN communication unit 11 transmits and receives a wireless signal in a band determined by IEEE802.11. For example, a wireless LAN card or a wireless LAN board is used as the wireless LAN communication unit 11. For example, a connector having an RJ45 type terminal, a USB connector, or the like is connected to the input / output unit 12. For example, the image data of the situation around the transmission source terminal device 1 photographed by a USB camera externally attached to the transmission source terminal device 1 is a communication path formed by several of the ad hoc relay devices 3 to 10. Via the transmission destination terminal device 2.

  The storage device 14 stores an OS for a personal computer and a computer program according to this embodiment executed on the OS. As the storage device 14, a magnetic disk such as a hard disk or a floppy (registered trademark) disk, an optical disk such as a CD-ROM, a DVD-ROM, or a BD-ROM, or a card memory is used. The storage device 14 may be configured using a USB memory attached externally via the input / output unit 12. These storage media or storage media can be combined as appropriate to be used as the storage device 14. The storage device 14 also has temporary storage means such as RAM.

  Further, the CPU 13 and the storage device 14 realize a function of a control unit (second control unit) 15 that controls suspension and activation of the ad hoc relay devices 3 to 10 as nodes on the communication paths R1 and R2. In the ad hoc communication system according to the present embodiment, the control for suspending the ad hoc relay apparatuses 3 to 10 is a state in which only the timer is operated while both the transmission and reception processes are stopped for the state of the ad hoc relay apparatuses 3 to 10. Refers to the control to make.

  The control unit 15 can exchange messages with the control units of the ad hoc relay apparatuses 3 to 10 in accordance with the communication procedure of the ad hoc routing protocol. The CPU 13 and the storage device 14 also realize a function as a path setting unit that sets a plurality of, for example, two communication paths R1 and R2.

  Further, the control unit 15 receives the received power level of these ad hoc relay devices 3 to 10 sent from the ad hoc relay devices 3 to 10 and the position information of these ad hoc relay devices 3 to 10 sent from the ad hoc relay devices 3 to 10. And a packet arrival rate which is a ratio of the number of packets received by the ad hoc relay devices 3 to 10 to a predetermined number of packets sent from the transmission source terminal device 1, and what percentage of the battery power is at full charge It collects the remaining battery level indicating whether or not there is. These received power level, position information, and packet arrival rate are the radio waves for predicting whether the local terminal is within the range where the radio signal from the ad hoc relay device reaches after a predetermined time, or whether the local terminal is outside this range. Information about the propagation status.

  The control unit 15 creates a schedule in which an operation command is described based on the received power level, the moving speed of the ad hoc relay device calculated from the position information, the packet arrival rate, and the remaining battery level.

  The operation command is to turn on the ad hoc relay devices 4, 5, 6 constituting the communication path R1, and to turn off the ad hoc relay devices 8, 9, 10 constituting the communication path R2. The devices 4, 5, 6 are turned off and the ad hoc relay devices 8, 9, 10 are turned on. The control unit 15 instructs the wireless LAN communication unit 11 to distribute this schedule to the ad hoc relay apparatuses 3 to 10. When there are two communication paths, these communication paths R1 and R2 are switched alternately based on this operation command.

  This schedule includes information on the command time such that the pause process is performed after several minutes from a certain time and the restart process is performed after a few minutes. The same schedule is relayed between the ad hoc relay devices 4, 5 and 6, and between the ad hoc relay devices 8, 9 and 10, respectively. Since all of the ad hoc relay apparatuses 3 to 10 measure the latitude and longitude using GPS, time synchronization can be established between these ad hoc relay apparatuses 3 to 10. Therefore, the ad hoc relay apparatuses 3 to 10 are configured to perform the switching operation at the same timing from the operation start time described in the operation command.

  The transmission source terminal device 1 is operated by an operator. In addition, various types of communication can be performed using the transmission source terminal device 1, and the operation of each ad hoc relay device can be controlled.

  The transmission destination terminal device 2 in FIG. 1 is a communication partner terminal of the transmission source terminal device 1 and is a terminal device such as a personal computer. The configuration of the transmission destination terminal device 2 is the same as that of the transmission source terminal device 1.

  The ad hoc relay devices 3 to 10 are terminal devices having a communication function using a wireless LAN and a function of outputting position information using GPS. For example, a notebook personal computer equipped with a wireless LAN card or a wireless LAN board is used for the ad hoc relay apparatuses 3 to 10.

  FIG. 3 is a schematic configuration diagram of hardware of the ad hoc relay apparatus 3. The ad hoc relay device 3 generates the position information of its own terminal from the wireless LAN communication unit 16 that transmits / receives a radio signal in a high frequency band based on the communication procedure corresponding to the IEEE 802.11 standard, and the positioning data from the GPS signal, and outputs the position information An input / output unit 18 for inputting / outputting data between an external peripheral device (not shown), a CPU 19 for calculation, a storage device 20 for storing programs and data, and these radios A LAN communication unit 16, a GPS receiver 17, an input / output unit 18, a CPU 19, and a power supply 21 that supplies power to the storage device 20 are provided.

  The wireless LAN communication unit 16 transmits and receives wireless signals in a band determined by IEEE 802.11. The wireless LAN communication unit 16 can output the value of the received electric field strength of the wireless signal. The value of the received electric field strength is read by the CPU 19 as the received power level.

  The GPS receiver 17 acquires positioning data, and generates and outputs position information of the terminal including the latitude and longitude from the positioning data. The input / output unit 18 has an interface function for connecting, for example, an RJ45 connector or a USB connector.

  The storage device 20 stores an OS for a personal computer and an application executed on the OS. The storage device 20 includes a hard disk, a floppy (registered trademark) disk, a CD-ROM, a DVD-ROM, a BD-ROM, a card memory, a USB memory externally connected via the input / output unit 18, or a recording medium thereof. Alternatively, an appropriate combination of storage media is used. The storage device 20 has temporary storage means such as RAM.

  The functions of the control unit (first control unit) 22 of the ad hoc relay device 3 are realized by the CPU 19 and the storage device 20. The control unit 22 can exchange messages with the control unit 15 of the transmission source terminal device 1 and the control units of the ad hoc relay devices 4 to 10 other than the ad hoc relay device 3. The controller 22 can also read the remaining battery level of the power source 21.

  The control unit 22 sets a timer value in the CPU 19 based on the schedule operating time information from the transmission source terminal device 1, and the CPU 19 gets up again by counting down the timer value. Thereby, the ad hoc relay apparatus 3 in a dormant state can be activated or resumed.

  The hardware configuration of the ad hoc relay device 4 to the ad hoc relay device 10 is the same as the hardware configuration of the ad hoc relay device 3.

  An example of the operation of the control unit 15 of the transmission source terminal device 1 in the ad hoc communication system according to the present embodiment having such a configuration will be described. FIG. 4 is a flowchart for explaining the processing contents of the control unit 15 of the transmission source terminal device 1.

  In step A1, the transmission source terminal device 1 wirelessly transmits, for example, a message for inquiring about the packet transfer route in accordance with the OLSR communication procedure, and each of these ad hoc relay devices 3 to 10 receives the message. 10 is collected as the route information. The transmission source terminal device 1 creates an ad hoc network topology based on the path information collected from the ad hoc relay devices 3 to 10, and distributes this topology to the ad hoc relay devices 3 to 10. Thereby, two communication paths from the transmission source terminal apparatus 1 to the transmission destination terminal apparatus 2 are formed, for example, a communication path R1 and a communication path R2.

  In step A2, the transmission source terminal device 1 collects the received power levels of the ad hoc relay devices 3 to 10 from the ad hoc relay devices 3 to 10 for a certain period of time. When the transmission source terminal device 1 determines that the reception power level of any one of the ad hoc relay devices 3 to 10 is decreasing with time, any of the ad hoc relay devices 3 to 10 is the transmission source terminal device. Predict that it is moving away from 1. When there is an ad hoc relay device that moves outside the range in which the radio of the terminal group reaches, the transmission source terminal device 1 creates a schedule for switching the communication routes R1 and R2 so that at least one communication route is secured.

  For example, if the source terminal device 1 estimates that the ad hoc relay device 5 will move to another location 30 minutes after the current location, the source terminal device 1 uses the ad hoc relay devices 4 to 4 constituting the communication path R1. 6 is suspended after 30 minutes, and the ad hoc relay apparatuses 8 to 10 constituting the communication path R2 are scheduled to wake up after 30 minutes. The transmission source terminal device 1 distributes this schedule to all the ad hoc relay devices 3 to 10.

  As another method in the case of determining using the power level, if the transmission source terminal device 1 determines that the received power level of any one of the ad hoc relay devices 3 to 10 is smaller than the threshold stored in advance, ad hoc A schedule for switching the communication paths R1 and R2 so that one of the relay apparatuses 3 to 10 is suspended or one of the relay apparatuses 3 to 10 is moved out of a wireless reachable range is secured. It can also be created.

  In step A3, the transmission source terminal device 1 collects the remaining battery levels of the ad hoc relay devices 3 to 10 from the ad hoc relay devices 3 to 10, respectively. If the source terminal device 1 determines that the remaining battery level of any one of the ad hoc relay devices 3 to 10 is smaller than a predetermined remaining battery level threshold, the ad hoc relay determined to be low. Estimate how many minutes the device can be operated, and create a schedule for switching communication paths so that at least one communication path is secured.

  For example, the transmission source terminal device 1 determines from the remaining battery level, and for example, the ad hoc relay device 4 can operate for about 20 minutes, but estimates that the power of the power source is insufficient after 20 minutes. . Based on the acquired topology of the ad hoc network, the transmission source terminal device 1 predicts that the ad hoc relay device 4 on the communication route R1 may leave the communication route R1 as a terminal group. The transmission source terminal device 1 creates a schedule so that another communication route R2 is secured as a communication route. The operation command of this schedule is such that each ad hoc relay device 4-6 on the communication path R1 is continuously activated until 20 minutes have passed, and after 20 minutes have elapsed, each ad hoc relay device 8-10 on the communication path R2 is suspended. It is.

  By this scheduling, since these ad hoc relay devices 8 to 10 can be kept in a dormant state until the ad hoc relay devices 8 to 10 are activated, the power of the power supply 21 of the ad hoc relay devices 8 to 10 can be saved. Can do.

  In step A4, the transmission source terminal device 1 collects the position information of each of the ad hoc relay devices 3 to 10 from each of the ad hoc relay devices 3 to 10. The transmission source terminal device 1 associates the IP address of the ad hoc relay devices 3 to 10 with the positional information including the latitude and longitude for each of the ad hoc relay devices 3 to 10 and stores the information in the storage device 14 of the transmission source terminal device 1. Write once. The transmission source terminal device 1 calculates the moving speeds of the ad hoc relay devices 3 to 10 based on changes in latitude and longitude values of the ad hoc relay devices 3 to 10 within a certain time. The transmission source terminal device 1 holds a movement speed threshold value in advance, and the transmission source terminal device 1 determines whether each movement speed obtained by the calculation is larger than this threshold value.

  If the source terminal device 1 determines that the moving speed is lower than the threshold value, it is assumed that the ad hoc relay device is stopped, or that the ad hoc relay device is present within a radio reachable range. When it is determined that the moving speed is greater than the threshold, the transmission source terminal device 1 estimates that the ad hoc relay device is operating or the ad hoc relay device is out of the terminal group.

  For example, if the source terminal device 1 predicts that the ad hoc relay device 4 on the communication route R1 may leave the terminal group on the communication route R1, based on the topology of the ad hoc network, the source terminal device 1 Create a schedule that instructs relay devices 4-6 to enter a dormant state 60 minutes after the current time, and instructs the resting ad hoc relay devices 8-10 to resume 60 minutes later. . The source terminal device 1 distributes this schedule to all the ad hoc relay devices 3 to 10, and after 60 minutes, the communication route is switched from the communication route R1 to the communication route R2 so that the communication route R2 is secured. Is called.

  Further, in step A5, the transmission source terminal device 1 sends out packets for measuring the packet arrival rate to the ad hoc relay devices 3 to 10 for a predetermined time, for example, 100 packets. These ad hoc relay devices 3 to 10 count how many of the 100 packets can be received, and send the counted result back to the transmission source terminal device 1 as a packet arrival rate. The transmission source terminal device 1 holds a threshold for the packet arrival rate in advance, and the transmission source terminal device 1 compares each packet arrival rate from the ad hoc relay devices 3 to 10 with the threshold value, When the rate is smaller than this threshold, it is determined that the radio signal propagation state between the ad hoc relay device having the packet arrival rate and the source terminal device 1 is bad. On the other hand, when the packet arrival rate is larger than the threshold, the transmission source terminal device 1 determines that the radio signal propagation state between the ad hoc relay device having the packet arrival rate and the transmission source terminal device 1 is good.

  As a result, the transmission source terminal device 1 can determine whether or not those devices are still in the positions of the ad hoc relay devices 3 to 10 that are grasped as the topology. In addition, when the value of the packet arrival rate is lower than the threshold value, the transmission source terminal device 1 determines to change from the communication path R1 to the communication path R2. In other words, the ad hoc relay apparatuses 4 to 6 configuring the communication path R1 are put into a dormant state, while the ad hoc relay apparatuses 8 to 10 configuring the communication path R2 functioning as a more stable transmission path are switched to the occurred state. Therefore, the transmission source terminal device 1 schedules the operation so that the terminal group composed of the ad hoc relay devices 4 to 6 and the terminal group composed of the ad hoc relay devices 8 to 10 are replaced, for example, after 60 minutes. It can be said that.

  Further, the control unit 15 of the transmission source terminal device 1 creates a schedule by combining at least one of the received power level, the remaining battery level, the moving speed, and the packet arrival rate of each of the ad hoc relay devices 3 to 10. You can also. The control unit 15 performs prediction based on the remaining battery level in addition to the received power level, the moving speed, and the packet arrival rate. For example, the control unit 15 predicts whether or not the ad hoc relay apparatus 5 exists as one node of the communication path R1 after 60 minutes, or the ad hoc relay apparatus 9 leaves the communication path R2 after 60 minutes. A prediction that the relay device continues to exist on the route R1 or R2 or the relay device leaves the communication route is performed according to the state of the radio link. Thereby, one of the communication paths R1 and R2 is selected.

  As another method for creating a schedule, the control unit 15 of the transmission source terminal device 1 sets a large threshold value in advance when determining by comparing the movement amount of the ad hoc relay devices 3 to 10 with the threshold value. By setting the schedule, any of the ad hoc relay apparatuses 3 to 10 stops the movement on the way, and the schedule is created in consideration of the movement speed error.

  In step A6, the transmission source terminal apparatus 1 determines the state of the communication paths R1 and R2 and determines the communication path R1 or R2 to be used, and then passes through the Yes route. In step A7, the transmission source terminal apparatus 1 In step A8, the transmission source terminal device 1 distributes this schedule to all the ad hoc relay devices 3 to 10.

  In step A9, the transmission source terminal device 1 continues to monitor whether there is an abnormality in the communication path. If it is determined that there is an abnormality in the communication path, the transmission source terminal device 1 passes through the Yes route, and determines whether communication is completed in Step A10. In step A10, if it is determined that the communication is not completed, the transmission source terminal device 1 passes the No route, returns to step A1, and if it is determined that the communication is completed, passes the Yes route and ends the processing. .

  In step A6, when the transmission source terminal apparatus 1 determines that switching between the communication paths R1 and R2 is necessary depending on the state of the wireless link such as the reception power level, the process returns to step A1 through the No route.

  All the ad hoc relay apparatuses 3 to 10 continue to monitor whether or not the switching time has arrived according to the schedule. When the switching time arrives, the operations of the wireless LAN communication unit 16 and the GPS receiver 17 are stopped and the schedule is stopped. It enters a standby state and pauses until the time commanded by. The control unit 22 of the ad hoc relay device that rises among the ad hoc relay devices 3 to 10 restarts the operations of the wireless LAN communication unit 16 and the GPS receiver 17. As a result, the ad hoc relay device configuring one communication path is set in an operating state, and all the ad hoc relay devices configuring other communication paths are set in a dormant state.

  In summary, in the ad hoc communication system according to the present embodiment, when there are two communication routes, the source terminal device 1 serves as each ad hoc relay device 3 as a node constituting the two communication paths R1 and R2. 10 to 10 schedules are created, and this schedule is distributed to all the ad hoc relay apparatuses 3 to 10.

  While the ad hoc relay apparatuses 4 to 6 constituting the communication path R1 are operating according to the generated operation schedule, the ad hoc relay apparatuses 8 to 10 constituting the communication path R2 stop the transmission / reception operation. . According to the schedule, the ad hoc relay apparatuses 8 to 10 are activated after a predetermined time has elapsed.

  The transmission source terminal apparatus 1 checks the communication path, confirms that the communication path R1 and the communication path R2 exist, and then stops the ad hoc relay apparatuses 4 to 6 constituting the communication path R1. These ad hoc relay apparatuses 4 to 6 are activated after a predetermined time according to the schedule.

  The transmission source terminal device 1 checks the communication route, confirms that the communication routes R1 and R2 exist, and then performs transmission / reception operations of the ad hoc relay devices 8 to 10 constituting the communication route R2. Stop.

  By repeatedly performing the above operation, in the ad hoc communication system according to the present embodiment, it is possible to extend the battery life of the ad hoc relay apparatuses 3 to 10 and to extend the operation time of the entire system. If the transmission source terminal apparatus 1 can confirm only one of the communication paths R1 and R2 when confirming the communication path, the transmission source terminal apparatus 1 changes the scheduling, and includes a schedule including the changed operation command. To deliver. As a result, the ad-hoc relay device of the communication path that has been used so far continues to be used.

  As described above, the ad hoc relay apparatuses 3 to 10 are managed and operated, so that the operation time of the entire system can be extended.

  Further, by causing the CPU 13 and the storage device 14 of the transmission source terminal device 1 to execute the computer program according to the present embodiment, the communication method in the ad hoc communication system according to the present embodiment is executed. The control unit 15 of the transmission source terminal device 1 performs ad hoc based on information that the ad hoc relay devices 3 to 10 are stationary or moving, or information that any of the ad hoc relay devices 3 to 10 is likely to move. It can be determined whether any one of the relay devices 3 to 10 is likely to go somewhere or whether it remains in that place.

  In addition, when the moving speeds of the plurality of ad hoc relay devices configuring the communication route R1 are high, the transmission source terminal device 1 preferentially uses the communication route R2. When the ad hoc relay devices 4 to 6 on the communication path R1 are not likely to move and the remaining battery level is sufficient, the transmission source terminal device 1 performs scheduling such as continuing to use the communication path R1.

  Specifically, the transmission source terminal device 1 detects that the remaining battery level of the ad hoc relay devices 8 to 10 constituting the communication path R2 is low, and the remaining battery level of the ad hoc relay device on the communication path R1 is sufficient. When this is detected, the transmission source terminal device 1 can use the communication path R1 to perform switching that causes the ad hoc relay devices 8 to 10 to pause. Further, in this state, when it is detected that any one of the ad hoc relay apparatuses 4 to 6 has moved slightly, but has not completely moved out of the wireless signal reachable range, the transmission source terminal apparatus 1 It is also possible to extend the time for using R1 and lengthen the time for resting the communication path R2. By distributing this schedule, it becomes possible to extend the operation time of the ad hoc relay apparatuses 8 to 10 constituting the communication path R2.

  As described above, a schedule can be created and distributed using the communication method and the computer program according to the present embodiment, and since this schedule is executed by the computers of the ad hoc relay devices 3 to 10, each ad hoc relay device 3 to 10 can suppress wasteful power consumption and extend the operation time of the entire system. In the case where there are a plurality of communication paths between the transmission source terminal apparatus 1 and the transmission destination terminal apparatus 2, it is avoided that the ad hoc relay apparatus configuring each communication path is always in a state of performing transmission / reception processing. .

  Thus, according to the ad hoc communication system according to the present embodiment, the communication method in this system, and the computer program used in this system, scheduling or time management is performed on the operation of the ad hoc relay device for each communication route. It is possible to reduce power consumption when operating an ad hoc wireless device, it is possible to extend the operation time of each ad hoc relay device, and it is possible to extend the operation time of the entire ad hoc communication system. .

(Modification)
(1) In the above embodiment, the ad hoc relay devices 3 to 10 suspend both the transmission and reception operations during the dormant state. However, in the ad hoc communication system according to the modification of the embodiment of the present invention, The ad hoc relay devices 3 to 10 can also perform the reception operation by pausing only the transmission operation. In this case, each of the ad hoc relay apparatuses 3 to 10 restarts the transmission process when receiving an activation command included in the schedule from the transmission source terminal apparatus 1. Any of the ad hoc relay devices 3 to 10 capable of direct wireless communication with the transmission source terminal device 1 receives this activation command from the transmission source terminal device 1 and resumes the transmission process. Thereafter, the resumed ad hoc relay device transmits a schedule including an activation command to any of the ad hoc relay devices 3 to 10 located in the transmission suspension state located downstream of the route, and the ad hoc relay device that has received this schedule Restart transmission processing. By performing this in sequence, each ad hoc relay device can be raised in turn.

  According to the ad hoc communication system according to this modification, the ad hoc relay devices 3 to 10 can monitor the surrounding radio conditions by continuing the reception process even after the suspension is instructed. This makes it easy to reconnect.

(2) Also, in the ad hoc communication system according to the present embodiment, the control unit 15 of the transmission source terminal device 1 monitors the moving speed of the ad hoc relay devices 3 to 10, and any of the ad hoc relay devices 3 to 10 is stationary. In this case, the control unit 15 can instruct the transmission process to be stopped only for the stationary ad hoc relay apparatuses 3 to 10. Alternatively, the control unit 15 may perform control such that only the ad hoc relay device having a large number of movements among the ad hoc relay devices 3 to 10 is stopped so that the transmission process is stopped and only the reception process is performed.

(3) Further, in the ad hoc communication system according to the present embodiment, the ad hoc relay apparatuses 3 to 10 can perform the intermittent reception process when the reception process is performed when the ad hoc relay apparatuses 3 to 10 are idle. . When intermittent reception is performed, various changes can be made such as shortening or extending the timing at which intermittent reception occurs.

(4) It should be noted that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

  In the above embodiment, the number of communication paths is two, but the number of communication paths may be three or more. Even when the number of communication paths is three or more, the control unit 15 of the transmission source terminal apparatus 1 pauses and resumes the transmission / reception processing of the ad hoc relay apparatus as a node configuring each communication path according to the schedule. In the above embodiment, OLSR is used as the routing protocol. However, the ad hoc communication system according to this embodiment can also use AODV as the routing protocol.

  Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment.

  The ad hoc communication system according to the present embodiment can be used for a communication infrastructure constructed by people dispatched to the site when a disaster or major accident occurs. The transmission source terminal device 1 and the transmission destination terminal device 2 are fixedly provided at two places away from each other in a place where the communication facility is broken or a large site for providing first aid. A plurality of persons each carry the communication terminal according to the present embodiment, and these persons temporarily cause each communication terminal to function as an ad hoc relay device at a position where each person is present. A plurality of communication paths are formed between the two points, and information data such as voices and images from each person is sequentially transferred from the transmission source terminal device 1 to the transmission destination terminal device 2 so that the person can grasp the situation at the site. It becomes possible to do. Even in this case, according to the ad hoc communication system according to the present embodiment, when each communication terminal as a node constituting the communication path moves, it is possible to suppress the waste of the power supply of these communication terminals. .

It is a figure which shows the example of arrangement | positioning in the area of the some radio | wireless terminal which comprises the ad hoc communication system which concerns on one Embodiment of this invention. It is a schematic block diagram of the hardware of a 1st terminal device. It is a schematic block diagram of the hardware of a radio | wireless terminal. It is a flowchart for demonstrating the process of the control part of a 1st terminal device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transmission source terminal device (1st terminal device), 2 ... Transmission destination terminal device (2nd terminal device), 3-10 ... Ad hoc relay apparatus (wireless terminal), 11 ... Wireless LAN communication part (wireless transmission / reception part), 12, 18 ... input / output unit, 13, 19 ... CPU, 14, 20 ... storage device, 15 ... control unit (second control unit), 16 ... wireless LAN communication unit (wireless transmission unit, wireless reception unit), 17, 23 ... GPS receiver, 21, 24 ... power source, 22 ... control unit (first control unit).

Claims (4)

A plurality of wireless terminals that form an ad hoc network, a first terminal device that performs wireless communication with any one of these wireless terminals, and any wireless terminal that forms this ad hoc network A second terminal device that performs wireless communication between them,
Each wireless terminal
Controls the transmission operation of the wireless reception unit that receives a wireless signal, the wireless transmission unit that wirelessly transmits route information indicating a plurality of wireless terminals capable of wireless transmission and reception, and information on the radio wave propagation status, and the wireless transmission unit A first control unit,
The first terminal device is
A wireless transmission / reception unit for transmitting / receiving a wireless signal and a route for setting a plurality of communication routes for transferring packets between the first terminal device and the second terminal device based on route information of each wireless terminal received by the wireless transmission / reception unit Based on the setting unit and the information on the radio wave propagation status sent from each of the wireless terminals, the wireless terminal configuring any one of these communication paths is turned on or off and the plurality of communications Create a schedule including an operation command with a content to turn off or turn on a wireless terminal that constitutes another communication path of the paths, and deliver the schedule to each wireless terminal to the wireless transceiver A second control unit for commanding,
An ad hoc communication system, wherein the first control unit of each wireless terminal pauses or activates the transmission operation of the wireless transmission unit based on an operation command included in the schedule received via the wireless reception unit .   The second control unit includes a reception power level of each wireless terminal received from each wireless terminal, a location of each wireless terminal, an arrival rate of packets from the first terminal device to each wireless terminal, and each wireless terminal The ad hoc communication system according to claim 1, wherein the schedule is created based on one or more of the remaining battery levels. A first terminal device that performs wireless communication with any wireless terminal that forms an ad hoc network performs wireless communication between the first terminal device and any wireless terminal that forms this ad hoc network. Setting a plurality of communication paths for transferring packets between the second terminal devices;
The first terminal device collects information on radio wave propagation status from one or more wireless terminals constituting any one of these communication paths;
Contents in which the first terminal device turns on one or more wireless terminals constituting any one of the communication paths and turns off a wireless terminal constituting another communication path among the plurality of communication paths. Creating a schedule including the operation command of the information based on the information on the radio wave propagation status;
The first terminal device distributes the schedule to a wireless terminal that operates in accordance with the operation command;
A communication method in an ad hoc communication system, comprising: A first terminal device that performs wireless communication with any wireless terminal that forms an ad hoc network performs wireless communication between the first terminal device and any wireless terminal that forms this ad hoc network. Setting a plurality of communication paths for transferring packets between the second terminal devices;
The first terminal device collects information on radio wave propagation status from one or more wireless terminals constituting any one of these communication paths;
Contents in which the first terminal device turns on one or more wireless terminals constituting any one of the communication paths and turns off a wireless terminal constituting another communication path among the plurality of communication paths. Creating a schedule including the operation command of the information based on the information on the radio wave propagation status;
The first terminal device distributes the schedule to a wireless terminal that operates in accordance with the operation command;
Is executed by a computer mounted on the first terminal device.

Images