JP4924948B2 - Wireless communication program - Google Patents

Description

  The present invention relates to a wireless LAN system, and more particularly to a technique for grasping in real time a communication status with a communication destination terminal in an ad hoc network.

  In recent years, wireless LAN systems based on the IEEE 802.11 standard have become widespread. Wireless LAN systems include an infrastructure network that communicates with devices or devices on a wired LAN via an access point, and an ad hoc network that communicates directly between wireless terminals without using an access point. In an ad hoc network, wireless terminals having a wireless communication function are interconnected as necessary to form a wireless LAN system.

  In the case of an infrastructure network, since communication is performed via an access point, the access point can centrally manage the communication quality (such as radio wave conditions) between the access point and each wireless terminal.

  On the other hand, in the case of an ad hoc network, there is no device that centrally manages communication like an access point. Therefore, individual wireless terminals that make up an ad hoc network cannot grasp the communication quality with a communication destination terminal in real time. Without any communication (communication using a data frame based on the IEEE 802.11 standard) and no response, the deterioration of communication quality has been confirmed. That is, in the conventional ad hoc network, the wireless terminal cannot individually know the communication quality with the communication destination terminal (see Non-Patent Document 1).

IEEE, “ANSI / IEEE Std 802.11, 1998 Edition”, 1998

  However, in the conventional method of not being able to individually know the radio wave status of other wireless communication destination terminals and confirming the deterioration of communication quality by performing some communication and no response, in the ad hoc network, the wireless terminal However, there is a problem that processing corresponding to a change in communication quality with the wireless communication destination terminal cannot be performed quickly.

  For example, as shown in FIG. 6, in a situation where the wireless terminal 50a establishes communication with a plurality of wireless terminals, for example, the wireless terminal 50d and the wireless terminal 50d Even if the communication quality deteriorates, the wireless terminal 50a cannot acquire the information immediately. In this case, the user of the wireless terminal 50a knows that communication is not possible until the wireless terminal 50d is used (for example, data is transmitted to the wireless terminal 50d). Further, when the communication quality with a wireless terminal (50b or 50c) other than the wireless terminal 50d is good, there is a possibility that a display indicating that the communication quality of the affiliated wireless network is good is displayed on the display unit of the wireless terminal 50a. In this case, the communication with the radio base station 50d cannot be performed even though the communication quality is displayed as good, which causes the user to be confused.

  The present invention has been made in view of the above problems, and an object of the present invention is to allow a wireless terminal to check communication quality with a communication destination terminal in real time in an ad hoc network.

  A first invention is a program for wirelessly communicating with an ad hoc network, the first step of transmitting a wireless probe request to an arbitrary wireless terminal belonging to the ad hoc network at an arbitrary timing, and the other wireless A second step of receiving a wireless probe response from a terminal; and, when receiving the wireless probe response, obtaining radio wave signal strength at the time of reception, identifying information of the other wireless terminal that has transmitted the wireless probe response, and The wireless terminal is caused to execute a third step of associating the signal strength with a radio signal strength and registering it in a communication quality table and a fourth step of referring to information registered in the communication quality table.

  2nd invention is the program as described in 1st invention, Comprising: The said communication quality table contains the transmission timing information which designates the timing which transmits a radio | wireless probe request | requirement, The said 1st step is the said transmission timing. The wireless probe request is transmitted according to the information.

  A third invention is the program according to the first or second invention, wherein the communication quality table includes wireless terminal designation information for designating a wireless terminal that is a transmission target of a wireless probe request. The step of transmitting a wireless probe request only to the wireless terminal designated by the wireless terminal designation information among the other wireless terminals, and when the third step receives a wireless probe response, Only when it is a wireless probe response from a wireless terminal designated by wireless terminal designation information, the radio signal strength at the time of reception is associated with the wireless terminal designation information and registered in the communication quality table.

  4th invention is the program in any one of 1st thru | or 3rd invention, Comprising: When the radio | wireless probe response was not received from the radio | wireless terminal registered into the said communication quality table, it was not received The wireless terminal is further caused to execute a step of registering the fact in the communication quality table.

  According to the present invention, since the wireless terminal periodically performs probe communication with the communication destination wireless terminal, the communication quality with the communication destination wireless terminal can be grasped in real time. The upper layer program can perform control in accordance with the communication quality with the communication destination wireless terminal.

(First embodiment)
FIG. 1 is an example of an ad hoc network according to the first embodiment of the present invention. The SSID of the ad hoc network 1 is “AdHoc_SSID”. Further, the wireless terminal 2a has established a connection in the wireless LAN with the wireless terminal 2b, the wireless terminal 2c, the wireless terminal 2d, and the wireless terminal 2e, and is in a communicable state.

  FIG. 2 is a diagram illustrating a hardware configuration example of a wireless terminal according to the present invention.

  The wireless terminal 2 is a personal computer, for example, and includes a CPU 10, an HDD 14, a ROM 12, a RAM 11, and a wireless LAN I / F (wireless LAN interface) 13. The CPU 10 controls each unit of the wireless terminal 2 according to an operating system and various programs stored in the HDD 14 or the ROM 12. The RAM 11 is a work area of the CPU 10 and temporarily stores programs and data being executed. The HDD 14 or the ROM 12 stores various programs such as an operating system and a wireless driver. The wireless LAN I / F 13 is a wireless communication circuit for performing wireless communication with an ad hoc network.

  FIG. 3 is a diagram illustrating a software configuration example of the wireless terminal according to the present invention.

  Each software shown in FIG. 3 is stored in the HDD 14 or the ROM 12. The operating system (OS) 20 is basic software for controlling the wireless terminal 2. The wireless driver 23 is a driver that controls the wireless LAN I / F 13, and manages and updates the probe communication described later and the communication quality table 23b. The wireless driver 23 provides an API (Application Program Interface) 23a, and the application 21 and the upper layer program 22 access resources (communication quality table and the like) managed by the wireless driver 23 by using the API 23a. You can also give orders. The upper layer program 22 is a program located in an upper layer of the wireless driver 23, and is, for example, a program such as IP (Internet Protocol) that manages communication in the Internet layer. The application 21 is application software that provides a user with a specific function, such as a Web browser, and operates on the operating system 20.

  FIG. 4 is a diagram illustrating an example of a communication quality table managed and updated by the wireless driver.

  The communication quality table is held on the RAM 11, for example. Index 30 is an identifier of each entry. The identification information 31 is information that uniquely identifies the wireless terminal of the communication destination, and stores the MAC address of the communication destination terminal as an example. The RSSI (Received Signal Strength Indication) 32 indicates the strength of the radio signal received by the wireless terminal.

  Next, the operation of the wireless LAN system in the first embodiment will be described with reference to FIG. 1, FIG. 3, and FIG.

  In FIG. 1, a wireless terminal 2a, a wireless terminal 2b, a wireless terminal 2c, a wireless terminal 2d, and a wireless terminal 2e form an ad hoc network having the SSID “AdHoc_SSID”. The wireless terminal 2a can communicate with the wireless terminal 2b, the wireless terminal 2c, the wireless terminal 2d, and the wireless terminal 2e.

  Hereinafter, the operation of the wireless terminal 2a will be described. First, the wireless terminal 2a periodically transmits a ProbeRequest to the wireless terminals of the communication destination (wireless terminal 2b, wireless terminal 2c, wireless terminal 2d, wireless terminal 2e).

  The wireless terminals (wireless terminal 2b, wireless terminal 2c, wireless terminal 2d, wireless terminal 2e) as communication destinations respond to the probe response when receiving the probe request. The probe response includes identification information (such as a MAC address) of a communication destination wireless terminal.

  When the wireless driver 23 of the wireless terminal 2a receives the probe response, the wireless driver 23 acquires the radio signal strength at the time of reception and registers the content in the communication quality table 23b. Specifically, identification information (MAC address or the like) of the communication destination terminal included in the probe response is associated with the acquired radio wave signal intensity and registered in the communication quality table 23b. In FIG. 1, since there are four wireless terminals (wireless terminal 2b, wireless terminal 2c, wireless terminal 2d, and wireless terminal 2e) as communication destinations, when a response of ProbeResponse is received from all of them, the communication quality table 23b includes Four pieces of information are registered.

  Here, it is assumed that the communication quality table 23b has the contents shown in FIG. Index “1” indicates information of the wireless terminal 2b, “2” indicates information of the wireless terminal 2c, “3” indicates information of the wireless terminal 2d, and “4” indicates information of the wireless terminal 2e.

  The application 21 and the upper layer program 22 can refer to the contents of the communication quality table 23b by calling the API 23a of the wireless driver 23. In the case of FIG. 4, it can be seen that the communication quality with the wireless terminal 2 e is deteriorated because the radio signal intensity with the wireless terminal 2 e registered in the index “4” is weak.

  For example, the application 21 and the upper layer program 22 lower the communication rate with the wireless terminal 2e, or notify the user of the wireless terminal 2a that the communication quality with the wireless terminal 2e has deteriorated. Processing can be performed.

  The wireless terminal 2a periodically updates the communication quality table 23b by performing probe communication (transmitting a probe request and receiving a probe response). Therefore, it is possible to know how much communication quality is ensured for each communication for the wireless terminal existing in the ad hoc network “AdHoc_SSID”. In addition, when the wireless terminal 2a does not receive the probe response from the wireless terminal of the communication destination, the wireless terminal 2a can quickly know that the wireless terminal has left the ad hoc network “AdHoc_SSID”.

  Thus, since the wireless terminal 2a can quickly grasp the communication quality with the communication destination terminal by referring to the communication quality table 23b, it can perform various processes according to the communication quality. For example, the wireless terminal 2a can change the settings of the multicast rate and the broadcast rate according to the change in communication quality. In addition, a threshold value is set in RSSI, a multicast address is changed based on the threshold value, and communication destination terminals that have good communication quality and high-speed packet communication can be used for communication requiring high speed or communication with a large data size. The communication method can be changed according to the communication quality so that the communication destination terminal that can perform only low-speed packet communication due to degraded communication quality performs communication with a small data size without requiring a speed.

  As described above, according to the first embodiment, the wireless terminal periodically performs probe communication with the communication destination wireless terminal, thereby grasping the communication quality with the communication destination wireless terminal in real time. Therefore, the application and the upper layer program can perform control according to the communication quality with the communication destination wireless terminal.

(Second Embodiment)
In the first embodiment, the wireless terminal periodically performs the probe communication with respect to all the communication destination wireless terminals. However, in the second embodiment, the communication destination terminal that performs the probe communication is specified. Explain the case. A case where a communication interval for performing probe communication is designated will also be described.

  The configuration example of the ad hoc network in the second embodiment is the same as that in FIG. Also, the hardware configuration example of the wireless terminal is the same as that shown in FIG. 2, and the software configuration example is the same as that shown in FIG. The content of the communication quality table is different from that in the first embodiment.

  FIG. 5 is a diagram illustrating an example of a communication quality table according to the second embodiment.

  The communication quality table is managed by the wireless driver as in the first embodiment. Index 40 is an identifier of each entry. The RSSI (Received Signal Strength Indication) 42 indicates the strength of the radio signal received by the wireless terminal. The registered terminal information 41 is information that uniquely identifies a wireless terminal that is an object of Probe communication, and stores the MAC address of the wireless terminal as an example. ReloadInterval 43 indicates an interval at which the wireless terminal performs Probe communication. In the case of the second embodiment, the registered terminal information 41 and the ReloadInterval 43 are designated in advance by the user of the wireless terminal.

  Of the information registered in the communication quality table, the registered terminal information 41 and the reload interval 43 are information set by the user, so that the settings may be effective even at the next startup after the power is turned off. . In this case, these pieces of information may be stored in a ROM, HDD, or the like.

  Next, the operation of the wireless LAN system in the second embodiment will be described with reference to FIG. 1, FIG. 3, and FIG.

  The operation of the wireless terminal 2a will be described. First, the user of the wireless terminal 2a registers in advance the wireless terminal information (registered terminal information) and ReloadInterval for checking the communication quality in the communication quality table 23b. Specifically, the user may access and register the registered terminal information 41 item and the reload interval 43 item in the communication quality table 23b from the UI (User Interface) of the wireless terminal 2a.

  Here, it is assumed that the user of the wireless terminal 2a has registered the registered terminal information shown in FIG. In FIG. 5, three wireless terminals are registered, and Index “1” is wireless terminal 2c, Index “2” is wireless terminal 2d, and Index “3” is wireless terminal 2e. The wireless terminal 2b is not registered.

  When the registered terminal information and Reload Interval are set by the user, the wireless terminal 2a connects to the ad hoc network having the SSID “AdHoc_SSID”.

  In FIG. 1, a wireless terminal 2a, a wireless terminal 2b, a wireless terminal 2c, a wireless terminal 2d, and a wireless terminal 2e form an ad hoc network having the SSID “AdHoc_SSID”. The wireless terminal 2a can communicate with the wireless terminal 2b, the wireless terminal 2c, the wireless terminal 2d, and the wireless terminal 2e.

  The wireless terminal 2a transmits a probe request to the wireless terminals (wireless terminal 2c, wireless terminal 2d, and wireless terminal 2e) registered in the communication quality table 23b at an interval of ReloadInterval 43 registered in the communication quality table 23b. . In the case of FIG. 5, since the wireless terminal 2c, the wireless terminal 2d, and the wireless terminal 2e are registered, the wireless terminal 2e is spaced every 5 seconds for the wireless terminal 2c and every 10 seconds for the wireless terminal 2d. Is sent at 8 second intervals.

  When the wireless terminal of the communication destination receives the Probe Request, it responds with a Probe Response. The probe response includes identification information (such as a MAC address) of a communication destination wireless terminal.

  When the wireless driver 23 of the wireless terminal 2a receives the probe response, the wireless driver 23 acquires the radio signal strength at the time of reception and registers the content in the communication quality table 23b. Specifically, the identification information (MAC address or the like) of the communication destination terminal included in the probe response is acquired, and it is determined whether or not the identification information matches the registered terminal information registered in the communication quality table 23b. If they match, the radio signal strength is acquired and associated with the matching registered terminal information and registered in the communication quality table 23b. In FIG. 1, the registered wireless terminals are the wireless terminal 2c, the wireless terminal 2d, and the wireless terminal 2e. Therefore, even if a ProbeResponse is received from another wireless terminal (for example, the wireless terminal 2b), the information is not registered. The wireless terminal 2a updates the communication quality table by performing probe communication (transmission of probe request and reception of probe response) at intervals specified by the reload interval.

  If a Probe Request is transmitted to a wireless terminal registered in the communication quality table 23b, but a Probe Response is not received from the wireless terminal (for example, the wireless terminal 2e), this is indicated in the communication quality table 23b. sign up. According to FIG. 5, the RSSI of the wireless terminal 2e registered in the index “3” is registered as “0”, which indicates that the probe response from the wireless terminal 2e has not been received.

  The application 21 and the upper layer program 22 can refer to the contents of the communication quality table 23b by calling the API 23a for acquiring the communication quality information of the wireless driver 23. The processing performed by the application 21 and the upper layer program 22 is the same as in the case of the first embodiment, and a description thereof will be omitted.

  In the case of the second embodiment, since the wireless terminal 2a transmits a ProbeRequest to the wireless terminals registered in the communication quality table 23b, for example, a wireless terminal (for example, a wireless terminal) that wants to detect participation in an ad hoc network. 2f (not shown)), the information may be registered in advance in the communication quality table 23b of the wireless terminal 2a as registered terminal information. In this way, it is possible to quickly detect that the wireless terminal 2f has joined the ad hoc network.

  As described above, according to the second embodiment, probe communication is performed only for wireless terminals registered in advance, so that it is possible to avoid an increase in the load on the ad hoc network due to the probe communication packet.

  Also, according to the second embodiment, since ProbeRequest is transmitted to a wireless terminal registered in advance, if the identification information of the wireless terminal that wants to detect participation in the ad hoc network is known, that information Is registered in the communication quality table, it is possible to quickly detect that the wireless terminal has joined the ad hoc network.

  The present invention is useful in a wireless ad hoc network when a wireless terminal grasps communication quality with a communication destination terminal in real time.

It is a figure which shows the structural example of the ad hoc network in the 1st and 2nd embodiment of this invention. It is a figure which shows the hardware structural example of the radio | wireless terminal in the 1st and 2nd embodiment of this invention. It is a figure which shows the software structural example of the radio | wireless terminal in the 1st and 2nd embodiment of this invention. It is a figure which shows an example of the communication quality table in the 1st Embodiment of this invention. It is a figure which shows an example of the communication quality table in the 2nd Embodiment of this invention. It is a figure which shows the structural example of the conventional ad hoc network.

Explanation of symbols

1 Ad hoc network 2a, 2b, 2c, 2d, 2e Wireless terminal

Claims (2)

  A program for causing a wireless terminal to perform wireless communication with an ad hoc network,
  The wireless terminal includes a wireless communication quality table including wireless terminal designation information related to a registered wireless terminal to which the wireless terminal transmits a wireless probe request.
  A first step of transmitting a wireless probe request at an arbitrary timing only to wireless terminals registered in the wireless communication quality table among other wireless terminals belonging to the ad hoc network;
  A second step of receiving a wireless probe response from the wireless terminal;
Only when the identification information of the wireless terminal included in the wireless probe response matches the identification information related to the registered wireless terminal, the radio signal intensity at the time of reception is acquired, and the identification information of the wireless terminal that has transmitted the wireless probe response And a third step of associating the radio signal strength with the communication quality table,
  A fourth step of referring to information registered in the communication quality table;
A program that causes a wireless terminal to execute. The program according to claim 1, wherein if a wireless probe response is not received from a wireless terminal registered in the communication quality table, the wireless terminal further executes a step of registering in the communication quality table that the wireless probe response has not been received. .

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