JP2011087061A - Radio communication system and radio equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide radio equipment allowing a transmission time interval of a control signal to be adjusted in accordance with a communication line, and to provide a radio communication system having the plurality of the radio equipment. <P>SOLUTION: A propagation delay time calculating part 330 receives an ACK signal from radio equipment 2 being a transmission destination of the data, acquires a time of receiving the ACK signal, and calculates a propagation delay time. An estimated distance calculating part 332 calculates an estimated distance between its own radio equipment 2 and the radio equipment 2 being the data transmission destination on the basis of the calculated propagation delay time. A line state acquiring part 334 acquires a parameter of a modulation system. A transmission time interval calculating part 336 calculates a transmission time interval of a path control message on the basis of the estimated distance between the radio equipment 2 calculated by the estimated distance calculating part 332 and the parameter of the modulation system acquired by the line state acquiring part 334. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wireless communication system and a wireless device.

  For example, in Patent Literature 1, in a radio station, an equalization unit equalizes a signal received from another radio station and detects an equalization error, and a quality determination unit detects the other radio station based on the equalization error. A wireless communication system in which a communication path determination unit determines a communication path from a local station to another wireless station by relaying one or more other wireless stations from the local station Disclose.

JP 2008-258702 A

  The present invention has been made from the background described above, and an object of the present invention is to provide a radio that can adjust a transmission time interval of a control signal according to a communication line, and a radio communication system having a plurality of radios.

  A wireless communication system according to the present invention is a wireless communication system that includes a plurality of wireless devices and communicates information via one or more wireless devices, and each of the plurality of wireless devices is connected to the wireless device. Distance calculating means for calculating the distance to each of the other wireless devices capable of communication, line status acquiring means for acquiring a parameter indicating a line status with the other wireless device, the calculated distance and the acquired And a time interval setting means for setting a time interval for transmitting a control signal for controlling a route of information communication to the other radio based on the parameter, and the control signal at the set time interval. Control signal transmitting means for transmitting to each of the wireless devices.

  In addition, the wireless device according to the present invention is a wireless device that communicates information via one or more other wireless devices, and calculates a distance from each of the other wireless devices that can communicate with the wireless device. In order to control the route of information communication based on the distance calculation means, the line status acquisition means for acquiring parameters indicating the line status with the other wireless device, and the calculated distance and the acquired parameters Time interval setting means for setting a time interval for transmitting the control signal to the other radio device, and control signal transmitting means for transmitting the control signal to each of the other radio devices at the set time interval. Have

  According to the wireless device and the wireless communication system according to the present invention, the transmission time interval of the control signal can be adjusted according to the communication line.

It is a figure which shows the radio | wireless communications system concerning 1st Embodiment. It is a sequence diagram which shows the process which mutually transmits / receives a path control message before each radio | wireless machine in a radio | wireless communications system communicates. It is a flowchart which shows the process after a radio | wireless machine receives a Hello message from another radio | wireless machine until it transmits a Hello message. It is a figure which shows the hardware constitutions of the radio | wireless machine concerning 2nd Embodiment. It is a figure which shows the radio | wireless communication program which operate | moves in the radio | wireless machine concerning 2nd Embodiment. It is a chart with which a transmission time interval calculation part calculates in order to calculate a transmission time interval. It is a flowchart which shows the process which the radio | wireless machine concerning 2nd Embodiment updates a transmission time interval.

[First Embodiment]
First, the first embodiment will be described.

FIG. 1 is a diagram illustrating a wireless communication system 1 according to the first embodiment.
The wireless communication system 1 includes wireless devices 100-1 to 100-3.
In the following description, when any one of a plurality of components such as the radio devices 100-1 to 100-3 is indicated without being specified, the radio device 100 may be simply abbreviated.
Also, hereinafter, the identifier of the wireless device 100-1 is # 1 and the wireless device 100-1 is referred to as "wireless device # 1", the identifier of the wireless device 100-2 is # 2, and the wireless device 100-2 is "wireless device". The wireless device 100-3 may be referred to as # 3, and the wireless device 100-3 may be referred to as “wireless device # 3”.
Hereinafter, devices such as the wireless device 100 that can be a subject of information processing and communication in the communication system may be collectively referred to as nodes.

In the wireless communication system 1, the wireless device 100-1 and the wireless device 100-2 exist in the communication area A, and the wireless device 100-2 and the wireless device 100-3 exist in the communication area B.
Each wireless device 100 can directly communicate within each communication area, but cannot directly communicate with the wireless device 100 outside the communication area.
For example, in the example of FIG. 1, the wireless device 100-1 cannot directly communicate with the wireless device 100-3.

Here, the wireless communication system 1 constructs an ad hoc network by the wireless devices 100-1 to 100-3.
That is, for example, the wireless device 100-1 can communicate with the wireless device 100-3 via the wireless device 100-2 that exists in both the communication areas A and B.
In the following description, radio devices existing in the same communication area may be referred to as adjacent nodes.

The wireless communication system 1 constructs a network that is compliant with OLSR (Optimized Link State Routing) protocol.
The OLSR protocol is a proactive type routing protocol, and, as will be described later with reference to FIG. 2, each wireless device 100 transmits a route control message such as a Hello message or a TC (Topology Control) message prior to communication. The communication path (link) is established before communication by transmitting / receiving.
As described above, in an ad hoc network compliant with the OLSR protocol, since a route is determined before communication, communication can be started immediately at any time.

Here, the Hello message is a path control message (control signal) transmitted periodically (for example, every 2 seconds) for the purpose of distributing information held by each wireless device 100.
The Hello message is transmitted (flooded) simultaneously from each wireless device 100 to all other wireless devices 100 that can communicate.
The radio device 100 receives the Hello message from the other radio device 100, collects its own peripheral information, establishes a logical connection with the other radio device 100, and configures a plurality of other radio devices 100. A relay node called MPR (multipoint relay) is determined from the inside.
By determining the MPR, the routing message is flooded efficiently.
The MPR is determined based on an index called Willingness that each radio device 100 has. The higher the Willingness value, the easier it is to select the MPR.

The TC message is a path control message periodically transmitted by the relay node selected as the MPR (radio device 100-2 in the example of FIG. 1). The relay node that transmitted the TC message, and the relay It includes information (topology information) related to a link with a set of radio devices 100 (MPR selector set) that has selected a node as an MPR.
Each wireless device 100 that has received the TC message calculates a route between any wireless device 100 based on the topology information, and creates a route table based on the calculation result.
With these route control messages, each wireless device 100 can communicate with all the wireless devices 100 in the wireless communication system 1 that has constructed an ad hoc network.

FIG. 2 is a sequence diagram showing a process (S10) of transmitting / receiving a path control message to / from each other before each wireless device 100 in the wireless communication system 1 performs communication.
Here, each wireless device 100 transmits a route control message according to its own transmission cycle (transmission time interval: for example, 30 seconds) in each of the following steps.
In step 100 (S100), the wireless device 100-2 transmits a Hello message to the wireless devices 100-1 and 100-3.
Here, in this step, since it is an initial stage, the link state is unknown. Therefore, this Hello message is of the “UNSPEC_LINK” type including the address (identifier # 2) of the radio device 100-2.

In Step 102-1 (S102-1), when receiving the Hello message (UNSPEC_LINK), the wireless device 100-1 confirms that a link from the wireless device 100-2 to the wireless device 100-1 is established.
Similarly, in step 102-2 (S102-2), when the wireless device 100-3 receives the Hello message (UNSPEC_LINK), it indicates that the link from the wireless device 100-2 to the wireless device 100-3 is established. Check.

In Step 104-1 (S104-1), the wireless device 100-1 transmits a Hello message to the wireless device 100-2.
Here, in this step, since it is unclear whether or not the link is a bidirectional link, this Hello message is an “ASYM_LINK” type indicating a one-way (asymmetric) link, and the radio 100-2 ( # 2) includes information indicating a link from the wireless device 100-1 (# 1).
Similarly, in Step 104-2 (S104-2), the wireless device 100-3 changes the wireless device 100-2 from the wireless device 100-2 (# 2) to the wireless device 100-3 (# 3). A Hello message (ASYM_LINK) including information indicating the link is transmitted.

In step 106-1 (S106-1), when the wireless device 100-2 receives the Hello message (ASYM_LINK) from the wireless device 100-1, the Hello message (UNSPEC_LINK) transmitted by the wireless device 100-2 is transmitted to the wireless device 100-1. 100-1 can confirm that it has been received.
Furthermore, since the wireless device 100-2 has received the Hello message from the wireless device 100-1, the wireless device 100-2 confirms that a bidirectional link between the wireless device 100-2 and the wireless device 100-1 has been established. .
Similarly, in Step 106-2 (S106-2), when the wireless device 100-2 receives the Hello message (ASYM_LINK) from the wireless device 100-3, the Hello message (UNSPEC_LINK) transmitted by the wireless device 100-2. Can be confirmed by the wireless device 100-3.
Furthermore, since the wireless device 100-2 has received the Hello message from the wireless device 100-3, it confirms that a bidirectional link between the wireless device 100-2 and the wireless device 100-3 has been established. .

In step 108 (S108), the radio device 100-2 transmits a Hello message (SYM_LINK), which is a bidirectional (symmetric) link type, to the radio devices 100-1 and 100-3.
The Hello message (SYM_LINK) indicates information indicating a bidirectional link between the wireless device 100-2 and the wireless device 100-1, and indicates a bidirectional link between the wireless device 100-2 and the wireless device 100-3, respectively. Contains information.

In step 110-1 (S110-1), when the wireless device 100-1 receives the Hello message (SYM_LINK), a bidirectional link has been established between the wireless device 100-2 and the wireless device 100-1. And that the bidirectional link is established between the wireless device 100-2 and the wireless device 100-3.
Similarly, in step 110-2 (S110-2), when the wireless device 100-3 receives the Hello message (SYM_LINK), a bidirectional link is established between the wireless device 100-2 and the wireless device 100-1. It is confirmed that a bidirectional link has been established between the wireless device 100-2 and the wireless device 100-3.

In Step 112-1 (S112-1), the wireless device 100-1 transmits a Hello message (SYM_LINK) to the wireless device 100-2.
This Hello message (SYM_LINK) is information indicating a bidirectional link between the radio device 100-2 and the radio device 100-1, and the radio device 100-3 is selected as the next adjacent node (NEXTHOP) of the radio device 100-2. Information (NEXTHOP: # 3), and information (MPR: # 2) indicating that radio apparatus 100-2 has been selected as the MPR.
Similarly, in Step 112-2 (S112-2), the wireless device 100-3 transmits a Hello message (SYM_LINK) to the wireless device 100-2.
This Hello message (SYM_LINK) is information indicating a bidirectional link between the wireless device 100-2 and the wireless device 100-3, and the wireless device 100-1 is selected as the next adjacent node (NEXTHOP) of the wireless device 100-2. Information (NEXTHOP: # 1), and information (MPR: # 2) indicating that the radio device 100-2 has been selected as the MPR.

Note that the order of the processes shown in FIG. 2 may be changed as appropriate.
The same applies to the flowcharts and sequences shown below.

In step 114 (S114), the radio device 100-2 selected as the MPR from the radio devices 100-1 and 100-3 transmits a TC message to the radio devices 100-1 and 100-3.
This TC message includes topology information indicating that a bidirectional link is established between the wireless device 100-2 and the wireless device 100-1, and between the wireless device 100-2 and the wireless device 100-3. Includes topology information indicating that a bidirectional link is established.
In Step 116-1 (S116-1), the wireless device 100-1 calculates a route to and from the wireless device 100-3 based on the received TC message, and creates a route table based on the calculation result. .
Similarly, in Step 116-2 (S116-2), the wireless device 100-3 calculates a route to and from the wireless device 100-1 based on the received TC message, and a route table based on the calculation result. Create

In Step 120-1 (S120-1), the wireless device 100-1 transmits data to the wireless device 100-3 via the wireless device 100-2 based on the created route table.
Similarly, in Step 120-2 (S120-2), the wireless device 100-3 transmits data to the wireless device 100-1 via the wireless device 100-2 based on the created route table. .

FIG. 3 is a flowchart showing a process (S20) from when the wireless device 100 receives a Hello message from another wireless device 100 until it transmits the Hello message.
In FIG. 3, the case where the wireless device 100-1 receives a Hello message from the wireless device 100-2 is illustrated.

In step 202 (S202), the wireless device 100-1 is activated, and software for ad hoc communication compliant with the OLSR protocol is activated.
In step 204 (S204), the wireless device 100-1 reads information (transmission time interval information) related to the time interval for transmitting the route control message from the database.
In step 206 (S206), the wireless device 100-1 receives a Hello message from the wireless device 100-2.
In step 208 (S208), the wireless device 100-1 analyzes the Hello message from the wireless device 100-2.

In step 210 (S210), the wireless device 100-1 determines whether or not the content of the Hello message is UNSPEC_LINK. If so, the process proceeds to S212, and if not, the process proceeds to S214.
In step 212 (S212), the wireless device 100-1 updates the link state with the wireless device 100-2 to ASYM_LINK.
In step 214 (S214), the wireless device 100-1 updates the link state with the wireless device 100-2 to SYM_LINK.
In step 216 (S216), the wireless device 100-1 adds information indicating the above-described link state to the Hello message transmitted to the wireless device 100-2.

In step 220 (S220), the wireless device 100-1 determines whether or not the transmission waiting time has become 0 seconds based on the transmission time interval information read in S204. If the transmission waiting time has not elapsed, the process returns to S206 (or S220 may be repeated).
In step 222 (S222), the wireless device 100-1 transmits a Hello message to the wireless device 100-2.
In step 224 (S224), the wireless device 100-1 determines whether or not to end the communication. If the communication is continued, the process returns to S206, and if the communication is to be ended, the process ends.

In the first embodiment, as described above, the wireless device 100 reads the transmission time interval information of the route control message from the database.
This database stores information related to optimal time intervals calculated in advance through experiments or the like, and this time interval is always constant.
Therefore, the wireless device 100 communicates with the case where the communication line changes frequently due to the movement of the other wireless device 100 at a long distance, and the case where the other wireless device 100 exists at a short distance and is almost stationary. A route control message is transmitted at the same time interval when the line is stable.

Here, when the communication line is stable, the link state with the other wireless device 100 does not change, so it is not necessary to frequently transmit a route control message for confirming the link state.
In addition, the processing capability of the wireless device 100 and the throughput of the communication line are reduced by the transmission of the route control message.
Therefore, there is a problem that the processing capability of the wireless device 100 and the throughput of the communication line are reduced due to unnecessary transmission of the routing control message, and data transmission / reception is not efficiently performed between networks.
The wireless device 2 described below is configured to solve the above problem.

[Second Embodiment]
Hereinafter, a second embodiment will be described.

FIG. 4 is a diagram illustrating a hardware configuration of the wireless device 2 according to the second embodiment.
In the wireless communication system according to the present embodiment, the wireless devices 100-1 to 100-3 are replaced with wireless devices 2-1 to 2-3 in the wireless communication system 1 according to the first embodiment described above. It has a configuration.

As shown in FIG. 4, the wireless device 2 includes an antenna 200, a transmission / reception circuit 202, an AD / DA conversion unit 204, a modem unit 206, a media access control unit 209, an input / output unit 210, a control unit 212, a storage unit 214, and a power source. Part 216.
The storage unit 214 includes an application unit 208.
In addition, hereinafter, each part constituting the wireless device 2 such as the transmission / reception circuit 202 may be collectively referred to as each constituent part.
Moreover, you may make it comprise the function of each component of the radio | wireless machine 2 shown in FIG. 4 with software.

The transmission / reception circuit 202 performs necessary processing on the high frequency received from another node via the antenna 200 and outputs the result to the AD / DA conversion unit 204.
The transmission / reception circuit 202 performs processing such as frequency conversion and amplification on the analog signal from the AD / DA converter 204.
Furthermore, the transmission / reception circuit 202 transmits the signal subjected to the above-described processing to another node via the antenna 200.
The AD / DA conversion unit 204 converts the analog signal from the transmission / reception circuit 202 into a digital signal and outputs the digital signal to the modulation / demodulation unit 206.
The AD / DA conversion unit 204 converts the digital signal from the modulation / demodulation unit 206 into an analog signal and outputs the analog signal to the transmission / reception circuit 202.

The modem unit 206 performs demodulation processing on the digital signal from the AD / DA conversion unit 204 and extracts information contained in the digital signal.
Further, the modem unit 206 outputs the extracted information to the media access control unit 209.
Also, the modem unit 206 performs modulation processing necessary for transmitting information from the media access control unit 209 to other nodes.
Further, the modem unit 206 outputs the modulated digital signal to the AD / DA converter unit 204.

The media access control unit 209 performs data transmission control such as wireless access.
The control unit 212 is an arithmetic device such as a CPU, for example, and controls each component of the wireless device 2.
In addition, the control unit 212 performs a predetermined process based on information from the application unit 208.
In addition, the control unit 212 controls the power supply unit 216 to control the power supply of each component other than the control unit 212.
Further, the control unit 212 executes a program stored in the storage unit 214.

The storage unit 214 is a memory, a storage medium, or the like, and stores information generated by the input / output unit 210 and information from other nodes.
The storage unit 214 stores a program necessary for realizing each function of the wireless device 2, and outputs a corresponding program in response to a request from each component.
The application unit 208 is a program executed by the control unit 212, and performs interface conversion for performing information processing between the input / output unit 210 and other components.

That is, the application unit 208 converts information received via the antenna 200 and the transmission / reception circuit 202 and information from each component into character information, image information, audio information, or the like so that the user can identify the information, Output to the input / output unit 210 under the control of the control unit 212.
In addition, the application unit 208 allows each component to process character information, image information, audio information, or the like from the input / output unit 210 or transmit the information to other nodes via the antenna 200. The data is converted and output to each component such as the modem unit 206.
Further, the application unit 208 stores information received from each component in the storage unit 214 or reads out necessary information from the storage unit 214.
The application unit 208 may perform processing such as routing control and adjustment of data transmission intervals.

The input / output unit 210 includes a user interface and includes, for example, a speaker, a microphone, a display, a keyboard, and the like, and may include a USB port and a LAN connection port for inputting / outputting data to / from an external device.
The input / output unit 210 outputs information input from an input device such as a microphone or a keyboard and information input from an external device or the like to the application unit 208.
The input / output unit 210 also outputs information from the application unit 208 to an output device such as a speaker or a display.

The power supply unit 216 supplies power to each component of the wireless device 2 under the control of the control unit 212.

FIG. 5 is a diagram illustrating a wireless communication program 30 that operates in the wireless device 2 according to the second embodiment.
As shown in FIG. 5, the wireless communication program 30 includes a communication processing unit 300, a transmission time interval information storage unit 302, a topology information storage unit 304, a link state information storage unit 306, a route control message generation processing unit 310, and a route control message. The transmission / reception unit 312, the path control message analysis unit 322, the topology information analysis unit 324, the propagation delay time calculation unit 330, the estimated distance calculation unit 332, the line status acquisition unit 334, and the transmission time interval calculation unit 336 are configured.
For example, the wireless communication program 30 is stored in the storage unit 214 and executed by the control unit 212 or the like.
That is, the wireless communication program 30 is executed by specifically using the hardware resources of the wireless device 2.

In the wireless communication program 30, the communication processing unit 300 performs processing necessary for performing communication with another wireless device 2 via a wireless network.
The transmission time interval information storage unit 302 stores transmission time interval information.
The topology information storage unit 304 stores topology information and manages a route table.
The topology information is information indicating the network configuration of the wireless devices 2-1 to 2-3, and is information indicating which wireless devices 2 are connected to each other.
The link state information storage unit 306 stores information (link state information) regarding the link state between the own wireless device 2 and another wireless device 2.
Furthermore, the link state information storage unit 306 stores routing information.
This routing information is information indicating the shortest path of data to be transmitted to the destination calculated based on the topology information. The destination and gateway identifier, the network identifier, the route weighting information, and the data are transmitted. Interface information.
Note that these link state information and routing information may be stored in separate components.

The route control message generation processing unit 310 acquires transmission time interval information from the transmission time interval information storage unit 302, acquires topology information from the topology information storage unit 304, and acquires link state information from the link state information storage unit 306. .
Further, the route control message generation processing unit 310 generates a route control message based on the acquired transmission time interval information, topology information, and link state information, and outputs it to the route control message transmission / reception unit 312.

The route control message transmission / reception unit 312 transmits (floods) a route control message to another wireless device 2 at a transmission time interval corresponding to the transmission time interval information stored in the transmission time interval information storage unit 302.
Further, the route control message transmission / reception unit 312 receives a route control message from another wireless device 2, and outputs the TC message to the route control message analysis unit 322 when the received route control message is a Hello message. Is output to the topology information analysis unit 324.
The path control message analysis unit 322 analyzes the Hello message, acquires the link state with the wireless device 2 that has transmitted the Hello message, and stores the link state information regarding the wireless device 2 in the link state information storage unit 306.
The topology information analysis unit 324 analyzes the topology information included in the TC message and creates a route table with other wireless devices 2.

The propagation delay time calculation unit 330 receives an ACK signal (acknowledgment signal) for data such as mail transmitted by the transmission / reception circuit 202 from the wireless device 2 that is the transmission destination of this data, and acquires the time when the ACK signal was received. To do.
Further, the propagation delay time calculation unit 330 is the time from the time when the data is transmitted to the time when the ACK signal is received, that is, the round trip of the signal between its own radio device 2 and the radio device 2 that is the data transmission destination. Time (propagation delay time) is calculated.

Based on the propagation delay time calculated by the propagation delay time calculation unit 330, the estimated distance calculation unit 332 calculates an estimated distance between its own wireless device 2 and the wireless device 2 that is the data transmission destination by, for example, the following equation: Calculate based on (1).
(1) Estimated distance [m] = (“propagation delay time [μsec]” − “data frame length [μsec]” − “CRC (Cyclic Redundancy Check) time [μsec]” − “shortest frame transmission interval (SIFS: short) interframe space) [μsec] ”−“ ACK frame length [μsec] ”) × (3.0 × 10 ² [m / μsec]) / 2
The calculation of the propagation delay time by the propagation delay time calculation unit 330 and the calculation of the estimated distance by the estimated distance calculation unit 332 are performed every time the wireless device 2 transmits data.

The line status acquisition unit 334 acquires a modulation scheme parameter in communication with another wireless device 2.
This parameter indicates which modulation method is used for communication.
Further, the line status acquisition unit 334 may acquire a modulation scheme parameter when the modulation scheme is changed by adaptive modulation or the like.

The transmission time interval calculation unit 336 transmits the route control message transmission time based on the estimated distance between the wireless devices 2 calculated by the estimated distance calculation unit 332 and the modulation scheme parameter acquired by the line status acquisition unit 334. Calculate the interval.
Also, the transmission time interval calculation unit 336 updates the transmission time interval information stored in the transmission time interval information storage unit 302 based on the calculated transmission time interval.
For example, the transmission time interval calculation unit 336 may calculate the transmission time interval periodically (for example, every 30 seconds).
Further, the transmission time interval calculation unit 336 may appropriately modify the weighting on the modulation scheme parameters and the like by the operation of the input / output unit 210 by the user.

The transmission time interval calculation unit 336 calculates the transmission time interval as follows, for example.
FIG. 6 is a chart provided for the transmission time interval calculation unit 336 to calculate the transmission time interval. FIG. 6A illustrates the communication quality management table, and FIG. 6B illustrates the correspondence between the inter-radio device distance and the time interval. The graph which shows is illustrated.
This communication quality management table is updated each time the processing of the propagation delay time calculation unit 330 and the line status acquisition unit 334 is performed.

FIG. 6A illustrates a communication quality management table of the wireless device 2-2 (wireless device # 2).
Since the adjacent nodes of the wireless device 2-2 are the wireless device 2-1 (wireless device # 1) and the wireless device 2-3 (wireless device # 3), a table is created for each wireless device 2-1 and 2-3. The
In the example of FIG. 6A, the current distance between the wireless device 2-2 and the wireless device 2-1 is 2 km, the distance 30 seconds before is 1 km, and the wireless device 2-2 and the wireless device 2- It is shown that the modulation method of communication with 1 is QPSK (Quadrature Phase Shift Keying).
From these pieces of information, the transmission time interval calculation unit 336 calculates the transmission time interval as 20 seconds using the graph shown in FIG.

Similarly, in the example of FIG. 6A, the current distance between the wireless device 2-2 and the wireless device 2-3 is 3 km, the distance 30 seconds before is 3 km, and the wireless device 2-2 is wireless. It is shown that the modulation method of communication with the device 2-3 is 16QAM (Qquadrature Amplitude Modulation).
From these pieces of information, the transmission time interval calculation unit 336 calculates the transmission time interval as 16 seconds using the graph shown in FIG.
Then, the shortest interval among the transmission time intervals for each wireless device is employed.
In the example of FIG. 6, the short time interval is 16 seconds, so the time interval at which the wireless device 2-2 transmits the route control message to the wireless devices 2-1 and 2-3 is 16 seconds. Is set.

Note that the slope of the graph in FIG. 6B can be changed as appropriate by a user operation.
In addition, in FIG. 6B, an example is shown in which the transmission time interval is calculated from the distance between the radios, but the difference between the distance 30 seconds before (previous) and the current distance, or The increase / decrease in the transmission time interval may be calculated based on both the difference and the distance between the wireless devices.
If the difference is calculated, the change direction and the change amount of the distance between the wireless devices can be known, so that an optimal transmission time interval can be set by predicting a future change in communication quality.
For example, when the distance changes in the increasing direction and the change amount is large, the transmission time interval is controlled to decrease more than when the change amount is small.
Conversely, when the distance is changing in the decreasing direction, the transmission time interval is controlled to increase as the change amount increases.

FIG. 7 is a flowchart illustrating processing (S30) in which the wireless device 2 according to the second embodiment updates the transmission time interval.
In FIG. 7, steps showing substantially the same processing as in FIG. 3 are denoted with the same reference numerals.
7 illustrates the case where the wireless device 2-1 receives a Hello message from the wireless device 2-2, the process illustrated in FIG. 7 is performed based on whether the wireless device 2 is selected as an MPR. Regardless, it is performed by all the radio devices 2 in the ad hoc network.

In step 302 (S302), the propagation delay time calculation unit 330 of the wireless device 2 receives an ACK from another wireless device 2 and calculates a propagation delay time.
In step 304 (S304), the estimated distance calculation unit 332 of the wireless device 2 calculates an estimated distance between the wireless device 2 of the wireless device 2 and the wireless device 2 that is the data transmission destination based on the calculated propagation delay time. To do.
In step 306 (S306), the channel status acquisition unit 334 of the wireless device 2 acquires a modulation scheme parameter indicating the channel status. In step 308 (S308), the transmission time interval calculation unit 336 estimates between the wireless devices 2. Based on the distance and the modulation scheme parameter, the transmission time interval of the route control message is calculated.

In step 310 (S310), the transmission time interval calculation unit 336 transmits the transmission time interval (interval A) corresponding to the transmission time interval information stored in the transmission time interval information storage unit 302 and the calculated transmission time interval (interval B). ) And determine whether or not the interval B is larger than the interval A.
If the interval B is larger than the interval A, the process proceeds to S312; otherwise, the process proceeds to S224.
That is, the interval A that is the initial value of the transmission time interval is the minimum time interval. This is because the initial value is set to a sufficiently small value in order to guarantee the path construction at the time of rising when the distance to the adjacent node is unknown.
In step 312 (S312), the transmission time interval calculation unit 336 updates the transmission time interval information stored in the transmission time interval information storage unit 302 based on the calculated transmission time interval (interval B).
Note that the initial transmission time interval stored in the transmission time interval information storage unit 302 may be, for example, a transmission time interval in the case of the maximum transmission distance.

By configuring an ad hoc network with the wireless device and the wireless communication system according to the second embodiment, it is possible to suppress the transmission of unnecessary route control messages, so it is possible to suppress a decrease in the processing capability of the wireless device and the throughput of the communication line, Data can be efficiently transmitted and received between networks.
Further, compared with the first embodiment, the wireless device according to the second embodiment can reduce the number of times of transmission of the route control message, thereby saving power consumption.
Further, compared with the first embodiment, the wireless device according to the second embodiment can reduce the transmission processing of the route control message, so that the capacity of the CPU and the like can be saved.

  The present invention is applicable to a radio device and a radio communication system.

DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 100 ... Radio equipment, 2 ... Radio equipment, 200 ... Antenna, 202 ... Transmission / reception circuit, 204 ... AD / DA conversion part, 206 ... Modulation / demodulation 208, application unit, 209 ... media access control unit, 210 ... input / output unit, 212 ... control unit, 214 ... storage unit, 216 ... power supply unit, 220 ... -Bus, 30 ... wireless communication program, 300 ... communication processing unit, 302 ... transmission time interval information storage unit, 304 ... topology information storage unit, 306 ... link state information storage unit, 310 ... route control message generation processing unit, 312 ... route control message transmission / reception unit, 322 ... route control message analysis unit, 324 ... topology information analysis unit, 330 ... at propagation delay Calculation unit, 332 ... estimated distance calculating section, 334 ... line status acquisition unit, 336 ... transmission time interval calculating unit

Claims (2)

A wireless communication system comprising a plurality of wireless devices and communicating information via one or more wireless devices,
Each of the plurality of radios is
Distance calculating means for calculating the distance to each of the other wireless devices capable of communicating with the wireless device;
A line status acquisition means for acquiring a parameter indicating a line status with the other wireless device;
Based on the calculated distance and the acquired parameter, a time interval setting means for setting a time interval for transmitting a control signal for controlling a route of information communication to the other radio device;
And a control signal transmission unit configured to transmit the control signal to each of the other wireless devices at the set time interval. A radio that communicates information via one or more other radios,
Distance calculating means for calculating the distance to each of the other wireless devices capable of communicating with the wireless device;
A line status acquisition means for acquiring a parameter indicating a line status with the other wireless device;
Based on the calculated distance and the acquired parameter, a time interval setting means for setting a time interval for transmitting a control signal for controlling a route of information communication to the other radio device;
A radio having control signal transmitting means for transmitting the control signal to each of the other radios at the set time interval.

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