JP5489262B2 - Communication interface activation control method, wireless terminal, and program - Google Patents

Description

  The present invention relates to a communication interface activation control method, a wireless terminal, and a program. In particular, the present invention relates to a technique for transferring a data packet through another wireless terminal.

  In recent years, with the development of a wireless communication network represented by a wireless local area network (LAN), the communication area is expanding. On the other hand, it is necessary to further cope with a communication area where the communication link is unstable and disconnection is likely to occur. For example, it corresponds to a communication area such as a subway or a highway.

  In order to enable communication as much as possible even in such a communication area, there is a technology of a link disconnection resistant network (DTN (Delay, Disruption, Disconnect Tolerant Network) (or Challenged Network)) (for example, non-patent document). 1). This technique assumes that communication links are not always available (often broken) and are unreliable. The DTN includes the meanings of a delay tolerant network and a communication failure tolerant network. Here, the DTN is mainly used as a “link disconnection tolerant network”.

  FIG. 1 is a schematic explanatory diagram of a link disconnection resistant network.

  In DTN, an end-to-end route to a communication partner terminal cannot always be found. Therefore, DTN adopts an architecture that transfers data in a bucket relay manner. According to DTN, a wireless terminal as a relay destination temporarily receives and holds all application data (for example, data for one e-mail). Then, the wireless terminal carries the data, and then transfers all application data to another wireless terminal. A communication method for transferring data by repeating such steps is generally referred to as “Store-carry-forward”.

  The DTN is different from an architecture in which a packet relay is performed for each packet after an end-to-end route is constructed, such as a so-called AODV (Ad hoc On-Demand Distance Vector).

  As described above, according to DTN, other wireless terminals are not always present within the radio wave reach of the wireless terminal. Therefore, if the wireless terminal always activates the communication interface even though no other wireless terminal exists in the radio wave reachable range, power is wasted. The wireless terminal is equipped with a battery such as a lithium ion battery from the viewpoint of portability. It is important to extend the battery by reducing the waste of power as much as possible.

  On the other hand, there is also a technique for periodically activating a wireless LAN interface and sensing an access point (see, for example, Non-Patent Document 2). According to this technology, it is possible to automatically switch from a cellular phone communication system to a wireless LAN communication system.

  In addition, there is a technique that uses area information of a cellular communication system and area information of a wireless LAN communication system in order to prevent a mobile phone terminal equipped with a wireless LAN interface from always starting the wireless LAN interface (for example, Non-Patent Document 3).

  Furthermore, there is a technique in which a server accumulates area information of a wireless LAN communication system (see, for example, Non-Patent Document 4). According to this technology, a mobile phone terminal equipped with a wireless LAN interface transmits current position information to a server via a mobile phone network. On the other hand, the server determines whether or not the current position of the mobile phone terminal is covered by the wireless LAN communication area, and returns the determination result to the mobile phone terminal. When the current position is covered by the wireless LAN communication area, the mobile phone terminal activates the wireless LAN interface. This eliminates the need to always activate the wireless LAN interface.

  Furthermore, there is a technology in which a cellular phone terminal equipped with a wireless LAN interface activates the wireless LAN interface according to cellular radio wave quality behavior (see, for example, Non-Patent Document 5). According to this technology, it is possible to monitor the behavior of the radio wave quality of the cellular and infer indoor entry with a high possibility of a wireless LAN area.

  There is also a sensor technology that detects a suspicious person by receiving a reflected wave with respect to a detection transmission radio wave (see, for example, Patent Document 1).

JP 2005-283543 A

V. Cerf, S. Burleigh, A. Hooke, L. Torgerson, R. Durst, K. Scott, K. Fall, H. Weiss, “Delay-Tolerant Networking Architecture,” RFC4838, Apr. 2007, [online], [ Search on April 21, 2009], Internet <URL: http://www.ietf.org/rfc/rfc4838.txt> “KDDI, mobile phone, PHS, wireless LAN automatic switching tool provided free of charge”, BB Watch Impress, [online], [Search April 16, 2009], Internet <URL: http://bb.watch. impress.co.jp/cda/news/2670.html> SuKyoung Lee and Nada Golmie, “Power-EfficientInterface Selection Scheme using Paging of WWAN for WLAN in Heterogeneous Wireless Networks,” IEEE International Conference on Communications (ICC) 2006, Jun. 2006. M. Ylianttila, J. Makela and K. Pahlavan, “Analysis of handoff in a location-aware vertical multi-access network,” ComputerNetworks 47 (2), Feb. 2005. H. Izumikawa, Y. Kishi and R. Nagareda, "Terminal-driven Coverage Area Detection with Low Power Consumption," IEICE Technical Report, NS2007-130, Mar. 2008.

  According to the technique described in Non-Patent Document 1, under a DTN environment, a wireless terminal needs to reduce power consumption and extend battery life by not activating a communication interface unnecessarily. The wireless terminal preferably finds another wireless terminal within the shortest possible communication interface startup time.

  Further, according to the technique described in Non-Patent Document 2, in order to periodically activate the communication interface, the communication interface is often activated wastefully in the DTN environment. When the wireless terminal is located outside the communication range and is located in a place where other wireless terminals are unlikely to approach, for example, at home, power is wasted due to activation of a useless communication interface, Battery life is shortened. On the other hand, if the regular startup time interval is set long, discovery of other wireless terminals will be delayed.

  In a base station (access point) -wireless terminal system, generally, a base station has a secured power source and transmits beacon signals intermittently at a time interval of, for example, 100 ms. On the other hand, the wireless terminal can receive the beacon signal transmitted from the base station by activating the communication interface at a predetermined timing for 100 ms or more. In this case, when the communication interface is activated, it can be immediately determined whether or not it is within the radio wave reachable range of the base station, depending on whether or not a beacon signal is received.

  However, in a wireless terminal-wireless terminal system in a DTN environment, wireless terminals start communication interfaces at predetermined timings and transmit beacon signals. Therefore, when one wireless terminal activates the communication interface and transmits a beacon signal, the other wireless terminal needs to activate the communication interface. Therefore, it is necessary to lengthen the startup time of the communication interface or shorten the startup interval of the communication interface, which wastes power.

  Furthermore, all the techniques described in Non-Patent Documents 3, 4 and 5 are based on the assumption that a mobile phone network can be used. For this reason, the communication system cannot be used in a DTN environment where there is a possibility that the communication system may not be used at all.

  A wireless terminal in a DTN environment preferably extends the activation time interval of the communication interface in a place where the possibility of communication by the bucket relay is low (for example, indoors where there is no person outside the communication range). Thereby, consumption of electric power can be reduced and the lifetime of a battery can be extended. On the other hand, in places where there is a high possibility of communication by bucket relay (for example, underground shopping malls), it is preferable to shorten the communication interface activation time interval. This facilitates discovery of other wireless terminals that are relay destinations, and facilitates discovery from other wireless terminals.

  Therefore, the present invention provides a communication interface activation control method capable of increasing the probability of finding another wireless terminal as a relay destination without wastefully activating a communication interface for a wireless terminal connected to a link disconnection resistant network. An object is to provide a wireless terminal and a program.

According to the present invention, in a startup control method of a communication interface in a wireless terminal,
A wireless environment measurement step of measuring a wireless environment variation value associated with a variation in wireless quality, and setting a first timer value to the first timer based on the wireless environment variation value; 1 timer value is repeated,
A first step of activating the communication interface for a fixed time when the first timer times out;
A second step of measuring a reception level in a predetermined frequency band transmitted from another wireless terminal and executing a link connection sequence for the other wireless terminal when the reception level is higher than a predetermined threshold;
A third step of transmitting a radio wave including a link connection request when the reception level is equal to or lower than a predetermined threshold;
A fourth step of stopping a communication interface when a link connection response is received from another wireless terminal, a link connection sequence is executed with the wireless terminal, and a link connection response is not received for a predetermined time or more; It is characterized by having.

According to the present invention, in a startup control method of a communication interface in a wireless terminal,
A wireless environment measurement step of measuring a wireless environment variation value associated with a variation in wireless quality, and setting a first timer value to the first timer based on the wireless environment variation value; 1 timer value is repeated,
A first step of activating the communication interface for a fixed time when the first timer times out;
A second step of transmitting a radio wave including a link connection request;
A third step of measuring a reception level in a predetermined frequency band transmitted from another wireless terminal, and executing the link connection sequence for the other wireless terminal when the reception level is higher than a predetermined threshold;
When the reception level is below a predetermined threshold, when a link connection response from another wireless terminal is received, when a link connection sequence is executed with the wireless terminal and the link connection response is not received for a certain time or more It is also preferable to have a fourth step of stopping the communication interface.

  According to another embodiment of the activation control method for a wireless communication interface of the present invention, for the wireless environment measurement step, the wireless environment variation value is a radio wave including a link connection request transmitted by the wireless terminal itself using the communication interface. It is also preferable to be based on a reflected wave with respect to.

  According to another embodiment of the wireless communication interface activation control method of the present invention, it is also preferable that the wireless environment fluctuation value is based on broadcast radio waves received using the broadcast interface in the wireless environment measurement step.

  According to another embodiment of the activation control method for a wireless communication interface of the present invention, in the wireless environment measurement step, the larger the wireless environment variation value, the shorter the first timer value is set, and the smaller the wireless environment variation value is. The first timer value is preferably set to be long.

According to the present invention, in a startup control method of a communication interface in a wireless terminal,
Wireless terminal
A broadcast interface for receiving radio waves for broadcast;
A first timer that repeats timing of the first timer value;
A second timer that repeats timing of the second timer value;
Have
When the second timer times out, start the broadcast interface,
Measure the wireless environment fluctuation value for broadcasting accompanying the change of wireless quality of broadcasting radio wave,
A second timer value corresponding to the broadcast radio environment fluctuation value is set in the second timer;
Set the first timer value corresponding to the failure counter to the first timer,
Stop the broadcast interface
Wireless environment measurement step;
A first step of activating the communication interface for a fixed time when the first timer times out;
A reception level in a predetermined frequency band transmitted from another wireless terminal is measured via the communication interface, and when the reception level is higher than a predetermined threshold, a second link connection sequence is executed for the other wireless terminal. And the steps
A third step of transmitting a radio wave including a link connection request via a communication interface when the reception level is equal to or less than a predetermined threshold;
When a link connection response from another wireless terminal is received via the communication interface, the link connection sequence is executed with the other wireless terminal, the failure counter is reset, while the link connection response is constant. A fourth step of stopping the communication interface and incrementing the failure counter by one if reception is not possible for more than the time;
It characterized in that it has a.

According to another embodiment of the wireless communication interface activation control method of the present invention,
The larger the radio environment variation value for broadcasting, the shorter the second timer value is set, and the smaller the radio environment variation value for broadcasting , the longer the second timer value is set.
It is also preferable that the first timer value is set shorter as the failure counter increases, and the first timer value is set longer as the failure counter decreases.

According to another embodiment of the wireless communication interface activation control method of the present invention,
It is also preferable that a link with another wireless terminal is controlled by a protocol for a link disconnection resistant network (DTN (Delay, Disruption, Disconnect Tolerant Network)).

According to the present invention, in a wireless terminal having a communication interface,
A wireless environment fluctuation measuring means for measuring a wireless environment fluctuation value associated with a change in wireless quality;
First timer means for setting the first timer value to the first timer based on the wireless environment fluctuation value and repeating the time measurement of the first timer value;
A communication interface activation control means for activating the communication interface for a predetermined time when the first timer times out;
Carrier sense means for measuring a reception level in a predetermined frequency band transmitted from another wireless terminal;
Link connection request transmission means for transmitting a radio wave including a link connection request after starting the communication interface or when the reception level is a predetermined threshold value or less;
Link connection response receiving means for receiving a link connection response from another wireless terminal and when the reception level is higher than a predetermined threshold or when a link connection response from another wireless terminal is received, to other wireless terminal Link connection processing means for executing a link connection sequence
The communication interface activation control means stops the communication interface when the link connection response cannot be received for a predetermined time or longer.

  According to another embodiment of the wireless terminal of the present invention, the wireless environment fluctuation value is preferably based on a reflected wave with respect to a radio wave including a link connection request transmitted by the wireless terminal itself using a communication interface. .

  According to another embodiment of the wireless terminal of the present invention, the wireless environment fluctuation value is preferably based on broadcast radio waves received using a broadcast interface.

  According to another embodiment of the wireless terminal of the present invention, the larger the wireless environment variation value, the shorter the first timer value is set, and the smaller the wireless environment variation value, the longer the first timer value is set. It is also preferable.

According to the present invention, in a wireless terminal having a communication interface,
A broadcast interface for receiving radio waves for broadcast;
First timer means for setting the first timer value corresponding to the failure counter to the first timer and repeating the time measurement of the first timer value ;
A broadcast radio environment change detecting means for measuring a radio environment change value for broadcasting due to radio wave of the radio quality fluctuation for feeding release,
A second timer value corresponding to a radio environment change value for feed release is set to the second timer, the second timer means for repeatedly counting the second timer value,
Broadcast interface activation control means for activating the broadcast interface when the second timer times out, and stopping the broadcast interface after measuring the radio environment fluctuation value for broadcasting;
A communication interface activation control means for activating the communication interface for a predetermined time when the first timer times out;
Carrier sense means for measuring a reception level in a predetermined frequency band transmitted from another wireless terminal via a communication interface;
Link connection request transmission means for transmitting a radio wave including a link connection request via the communication interface after starting the communication interface or when the reception level is a predetermined threshold value or less;
Link connection response reception means for receiving a link connection response from another wireless terminal and when the reception level is higher than a predetermined threshold or when a link connection response from another wireless terminal is received via the communication interface A link connection processing means for stopping a communication interface when a link connection sequence is executed with a wireless terminal, and a link connection response is not received for a certain time or more.
A failure counter means for incrementing a failure counter by 1 when a link connection response is not received, and resetting the failure counter when a link connection sequence is executed with another wireless terminal;
The communication interface activation control means stops the communication interface when the link connection response cannot be received for a predetermined time or longer.

  According to another embodiment of the wireless terminal of the present invention, it is also preferable that the link connection processing means controls a link with another wireless terminal by a protocol for link disconnection resistant network (DTN).

According to the present invention, in a program for causing a computer mounted on a wireless terminal having a communication interface to function,
A wireless environment fluctuation measuring means for measuring a wireless environment fluctuation value associated with a change in wireless quality;
First timer means for setting the first timer value to the first timer based on the wireless environment fluctuation value and repeating the time measurement of the first timer value;
A communication interface activation control means for activating the communication interface for a predetermined time when the first timer times out;
Carrier sense means for measuring a reception level in a predetermined frequency band transmitted from another wireless terminal;
Link connection request transmission means for transmitting a radio wave including a link connection request after starting the communication interface or when the reception level is a predetermined threshold value or less;
Link connection response receiving means for receiving a link connection response from another wireless terminal and when the reception level is higher than a predetermined threshold or when a link connection response from another wireless terminal is received, to other wireless terminal Link connection processing means for executing a link connection sequence
The communication interface activation control means makes the computer function so as to stop the communication interface when the link connection response is not received for a predetermined time or more.

  According to the communication interface activation control method, wireless terminal, and program of the present invention, for the wireless terminal connected to the link disconnection resistant network, the communication interface activation time interval is changed based on the wireless environment variation value, and the communication interface is When activated, by detecting the presence of another wireless terminal by carrier sense, it is possible to increase the probability of finding another wireless terminal to be a relay destination without unnecessarily activating the communication interface.

It is outline | summary explanatory drawing in a link cutting | disconnection tolerance network. It is explanatory drawing showing the fluctuation | variation of a radio environment. It is a 1st flowchart of the radio | wireless terminal in this invention. It is a sequence diagram showing exchange of a link connection request and a link connection response. It is a 2nd flowchart of the radio | wireless terminal in this invention. It is a flowchart of the radio | wireless terminal which has a broadcast interface. It is a function block diagram of the radio | wireless terminal in this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is an explanatory diagram showing changes in the wireless environment.

  FIG. 2A shows an environment in which the fluctuation of the wireless environment is small. “Radio environment fluctuation” is represented, for example, by the fluctuation range of the radio wave reception level over time (hereinafter referred to as “radio environment fluctuation value”). The environment in which the fluctuation of the wireless environment is small is, for example, an environment in which the wireless terminal is in a stationary state and other wireless terminals that are relay destinations are not moving around the wireless terminal. That is, it means that there is a low probability that a link is connected to another wireless terminal as a relay destination and data is carried.

  FIG. 2 (a1) represents a state where the wireless terminal is stationary at home such that there are no other wireless terminals around it. Further, according to FIG. 2 (a2), the reception level with respect to the frequency is represented for each time (t1, t2,...). It can be understood that the waveform of the reception level with respect to the frequency is similar for a plurality of times. Furthermore, according to FIG. 2 (a3), the fluctuation range of the reception level (history) with respect to the passage of time is represented. It can be understood that the variation of the reception level is small for a plurality of times in the predetermined time range.

  FIG. 2B shows an environment where the wireless environment varies greatly. An environment with a large wireless environment variation value is, for example, an environment in which the wireless terminal itself is in a moving state or another wireless terminal that is a relay destination is moving around the wireless terminal. That is, it means that there is a high probability that a link is connected to another wireless terminal as a relay destination and data is carried.

  FIG. 2 (b1) represents a state in which the wireless terminal is moving in a suburb where other wireless terminals exist around it. Further, according to FIG. 2 (b2), the reception level with respect to the frequency is represented for each time (t1, t2,...). It can be understood that the waveform of the reception level with respect to the frequency is different for a plurality of times. Furthermore, according to FIG. 2 (b3), the fluctuation range of the reception level (history) with respect to time is shown. It can be understood that the reception level varies greatly for a plurality of times within a predetermined time range.

  FIG. 3 is a first flowchart of the radio terminal according to the present invention. FIG. 4 is a sequence diagram showing exchange of a link connection request and a link connection response. According to FIG. 4, the communication interface activation time is 3 s and the activation interval is 10 s, but these are only examples.

  First, a case where the wireless terminal includes only a communication interface will be described. An embodiment provided with a broadcast interface will be described later. In addition, S34 represented by the wavy line is not executed for the embodiment including the broadcast interface. On the other hand, S391 and S392 represented by broken lines are executed only in the embodiment having a broadcast interface.

  The flowchart of FIG. 3 is started by timeout of the communication IF timer. The communication IF timer is set with the first timer value and repeats the time counting.

(S30) The wireless terminal activates the communication interface when the communication IF timer times out.
(S31) Next, the wireless terminal performs carrier sense. Specifically, the reception level in a predetermined frequency band of the radio wave transmitted from another wireless terminal is measured. This corresponds to S31 in FIG.
(S32) Next, the wireless terminal determines whether the carrier-sensed reception level is equal to or less than a predetermined threshold. Here, that the reception level is higher than the predetermined threshold (NO) means that the wireless terminal is located in the radio wave reachable range of another wireless terminal. In this case, the process proceeds to S38 in order to execute a link connection sequence from the wireless terminal to another wireless terminal. Conversely, the reception level being equal to or lower than the predetermined threshold (YES) means that there are no other wireless terminals around the wireless terminal. In this case, the process proceeds to S33.

(S33) When the reception level is equal to or lower than the predetermined threshold (YES), the wireless terminal transmits a radio wave including a link connection request. This corresponds to S33 in FIG. The link connection request may be a beacon signal, for example.

(S341) Here, the wireless terminal receives the reflected wave with respect to the radio wave including the link connection request transmitted by itself by the communication interface. This corresponds to S34 in FIG. Here, as shown in FIG. 2 described above, the reception level is measured in time series, and the wireless environment fluctuation value at a predetermined time interval is calculated.

  Note that the wireless environment variation value may be based on broadcast radio waves received using a broadcast interface.

(S342) Next, the wireless terminal sets the first timer value in the communication IF timer based on the wireless environment fluctuation value. The larger the wireless environment variation value, the shorter the first timer value is set, and the smaller the wireless environment variation value, the longer the first timer value is set. That is, the larger the wireless environment variation value, the higher the probability that communication with another wireless terminal is possible, and therefore the next timing to start the communication interface is shortened. On the other hand, the smaller the wireless environment variation value is, the lower the probability that communication with another wireless terminal is possible. Therefore, the timing for starting the communication interface next is lengthened.

(S35) In response to the link connection request transmitted in S33, the wireless terminal expects to receive a link connection response from another wireless terminal. Other wireless terminals can receive the link connection request transmitted from the wireless terminal as long as the communication interface is activated. At this time, if another wireless terminal can be linked, it transmits a radio wave including a link connection response. The wireless terminal can receive a radio wave including a link connection response transmitted from another wireless terminal. This corresponds to S35 in FIG.

For example, there are the following two cases where the wireless terminal cannot receive a radio wave including a link connection response.
(1) When there is no other wireless terminal within the reach of radio waves transmitted from the wireless terminal (2) There is another wireless terminal within the reach of radio waves transmitted from the wireless terminal If the communication interface on the other wireless terminal is not activated

(S36) The wireless terminal determines whether a radio wave including a link connection response has been received or has not been received.
(S37) When the radio terminal cannot receive the radio wave including the link connection response (NO), the radio terminal stops the communication interface.
(S38) If the reception level is higher than the predetermined threshold (NO) (shift from S32) or if the radio terminal has received a radio wave including a link connection response (YES) (shift from S36), etc. The link connection sequence is executed for the wireless terminals. This corresponds to S38 in FIG. Accordingly, the wireless terminal connects a link with another wireless terminal.

  The wireless terminal can transfer an application data packet to be transferred after a link connection is established with another wireless terminal.

  FIG. 5 is a second flowchart of the radio terminal according to the present invention.

FIG. 5 differs from FIG. 3 only in S31 to S34 and S51 to S54. Hereinafter, only different processes will be described.
(S51) The wireless terminal transmits a radio wave including a link connection request immediately after starting the communication interface.
(S52) Next, the wireless terminal measures a reception level in time series using a communication interface or a broadcast interface, and calculates a wireless environment fluctuation value at a predetermined time interval. Then, the first timer value is set in the communication IF timer based on the wireless environment fluctuation value.
(S53) Next, the wireless terminal performs carrier sense. Specifically, the reception level in a predetermined frequency band of the radio wave transmitted from another wireless terminal is measured.
(S54) Next, the wireless terminal determines whether the carrier-sensed reception level is equal to or less than a predetermined threshold. If the reception level is higher than the predetermined threshold (NO), the process proceeds to S58 in order to execute the link connection sequence from the wireless terminal to another wireless terminal. Conversely, if the reception level is less than or equal to the predetermined threshold (YES), the process proceeds to S55.

  FIG. 6 is a flowchart of a wireless terminal having a broadcast interface.

  When the wireless terminal activates both the communication interface and the broadcast interface, power consumption also increases. Therefore, FIG. 6 operates so as to reduce the number of activations of the communication interface as much as possible compared to the cases of FIGS.

The flowchart of FIG. 6 is started by the timeout of the broadcast IF timer. The broadcast IF timer is set with a second timer value and repeats the time counting.
(S60) The wireless terminal activates the broadcast interface when the broadcast IF timer times out.
(S61) The wireless terminal receives a broadcast wave broadcast from a terrestrial AM / FM radio broadcast, a terrestrial television broadcast, or a broadcast satellite through a broadcast interface. Here, the broadcast wave is preferably a radio wave that can be received at all times and has high permeability. The wireless environment fluctuation value in the broadcast wave is measured in time series, and the wireless environment fluctuation value at a predetermined time interval is calculated.
(S62) Next, the wireless terminal sets the second timer value in the broadcast IF timer based on the wireless environment variation value. The larger the wireless environment variation value, the shorter the second timer value is set, and the smaller the wireless environment variation value, the longer the second timer value is set.
(S63) The wireless terminal stops the broadcast interface.
(S64) Finally, the wireless terminal sets the first timer value in the communication IF timer according to the failure counter. The smaller the failure counter, the shorter the first timer value is set, and the more the failure counter, the longer the first timer value is set.

Here, the “failure counter” represents the continuous number of times that the communication interface has been stopped without discovering other wireless terminals even though the communication interface has been activated. According to FIG. 6, the flowchart of FIG. 3 is also represented, and S391 and S392 are additionally processed.
(S391) If another wireless terminal is found and the link connection sequence is executed, the “failure counter” is reset.
(S392) If other communication terminals cannot be found and the communication interface is stopped, the “failure counter” is incremented by one.

  According to the flowchart shown in FIG. 6, when the wireless terminal detects the wireless environment variation value using the broadcast interface, the process of S34 corresponding to FIG. 3 is not executed. This is because it is not necessary to detect the wireless environment fluctuation value by the reflected wave of the communication radio wave.

  FIG. 7 is a functional configuration diagram of the wireless terminal according to the present invention.

  According to FIG. 7, the wireless terminal 1 includes a communication interface 101 and a broadcast interface 111. The communication interface 101 is a wireless interface for communication and is connected to an antenna. The antenna may be separately provided for transmission / reception. Thereby, the wireless terminal 1 can communicate with other wireless terminals existing within the radio wave reachable range of the wireless terminal 1 via the air. In particular, the communication interface 101 can transmit a transmission signal amplified by a transmission amplifier and receive a reflected wave with respect to the transmission signal. The communication interface 101 and the broadcast interface 111 are configured by hardware, and activation of these interfaces involves transmission / reception of radio waves, and thus power consumption is large.

  On the communication interface side, the wireless terminal 1 includes a communication IF timer 100, a communication interface activation control unit 102, a communication wireless environment change detection unit 103, a carrier sense unit 104, a link connection request transmission unit 105, and a link connection. The response receiving unit 106 and the link connection processing unit 107 are included. These functional components are realized by executing a program that causes a computer installed in the wireless terminal to function.

  The communication interface activation control unit 102 activates the communication interface 101 when the communication IF timer times out with the first timer value. Further, the communication interface activation control unit 102 stops the communication interface 101 when the link connection response cannot be received for a predetermined time or longer.

  The communication wireless environment variation detection unit 103 measures a wireless environment variation value in the communication interface 101. This wireless environment variation value is based on a reflected wave with respect to a radio wave including a link connection request transmitted by the wireless terminal using the communication interface 101.

  The communication IF timer 100 repeats counting the first timer value and generates a timing for starting the communication interface 101. The communication IF timer 100 sets the first timer value shorter as the communication radio environment fluctuation value is larger, and sets the first timer value longer as the communication radio environment fluctuation value is smaller.

  The communication IF timer 100 may hold a first timer value for the communication radio environment variation value as a table. If the difference between the previous fluctuation value and the current fluctuation value is large, the first timer value is shortened (for example, 1/2), and if the difference is small, the first timer value is lengthened (for example, 2). Times). In this case, it is also preferable to preliminarily define a minimum value and a maximum value for the first timer value.

  The carrier sense unit 104 uses the communication interface 101 to measure a reception level in a predetermined frequency band transmitted from another wireless terminal. When the reception level is higher than the predetermined threshold, the carrier sense unit 104 instructs the link connection processing unit 107 to execute a link connection sequence for another wireless terminal. On the other hand, when the reception level is equal to or lower than the predetermined threshold, the carrier sense unit 104 instructs the link connection request transmission unit 105 to transmit the link connection request.

  In response to an instruction from the carrier sense unit 104, the link connection request transmission unit 105 transmits a radio wave including a link connection request.

  When receiving a link connection response from another wireless terminal, the link connection response receiving unit 106 instructs the link connection processing unit 107 to execute a link connection sequence. On the other hand, when the link connection response is not received, the communication interface activation control unit 102 is notified to that effect.

  The link connection processing unit 107 executes a link connection sequence for other wireless terminals in response to an instruction from the carrier sense unit 104 or the link connection response receiving unit 106. For example, the operation shifts to the operation of IEEE 802.11 CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance). The link connection processing unit 107 mounts the DTN protocol unit as an upper layer of the transport protocol unit. As the transport protocol unit, for example, existing TCP (Transmission Control Protocol), SCTP (Stream Control Transmission Protocol), UDP (User Datagram Protocol), DCCP (Datagram Congestion Control Protocol) or wireless TCP can be used.

  According to DTN, communication links are not always established with other wireless terminals. In order to realize the storage and transfer method, the DTN protocol unit stores application data packets received from other wireless terminals in a buffer. The application data packet is held during communication disconnection with another wireless terminal. Thereafter, when the link is connected to another wireless terminal, the application data is transferred.

  In addition, the wireless terminal 1 includes a broadcast IF timer 110, a broadcast interface activation control unit 112, a broadcast wireless environment variation detection unit 113, and a failure counter unit 114 on the broadcast interface side. These functional components are also realized by executing a program that causes a computer installed in the wireless terminal to function.

  The broadcast IF timer 110 repeats counting the second timer value and generates a timing for starting the broadcast interface 111. The broadcast IF timer 110 sets the second timer value shorter as the broadcast radio environment fluctuation value is larger, and sets the second timer value longer as the broadcast radio environment fluctuation value is smaller.

  When the wireless terminal measures the wireless environment variation value by the broadcast interface, the communication IF timer 100 sets the first timer value according to the failure counter value. When the failure counter value is large, the first timer value is increased, and the probability that the communication interface is activated is decreased. Conversely, when the failure counter value is small, the first timer value is decreased, and the probability that the communication interface is activated is increased.

  The broadcast interface activation control unit 112 activates the broadcast interface 111 when the broadcast IF timer 110 times out with the second timer value. In addition, the broadcast interface activation control unit 112 stops the broadcast interface 111 after measuring the broadcast radio environment variation value.

  The broadcast wireless environment fluctuation detection unit 113 measures the broadcast wireless environment fluctuation value in the broadcast radio wave. The broadcast radio environment fluctuation value is output to the broadcast IF timer 110.

  The failure counter unit 114 increments the failure counter by 1 when a link connection response from another wireless terminal cannot be received, and resets the failure counter when a connection sequence is executed with another wireless terminal.

Finally, the following two effects can be obtained from the result of computer simulation.
(1) When reducing the number of activations of the communication interface (reducing the total number of connection request messages transmitted) in order to reduce power consumption and extend battery life:
According to the present invention, the number of connection response messages received from other wireless terminals is reduced by about 33% compared to the prior art that periodically activates the communication interface, but the total number of messages transmitted exceeds that. Can be reduced.
(2) Furthermore, if you want to increase the number of connection response messages received:
According to the present invention, the number of connection response messages from other wireless terminals is increased by reducing the activation interval of the communication interface, and the total number of connection request messages transmitted is reduced as compared with the prior art. be able to.
As a result, according to the present invention, it is possible to reduce the number of transmissions of connection request messages required to discover other wireless terminals by about 40% compared to the prior art.

  As described above in detail, according to the activation control method, wireless terminal, and program of the communication interface of the present invention, the activation time of the communication interface is determined based on the wireless environment variation value for the wireless terminal connected to the link disconnection resistant network. When the communication interface is activated while changing the interval, the presence of another wireless terminal is detected by carrier sense, so that the other wireless terminal that becomes the relay destination can be found without wastefully activating the communication interface. Can increase the probability.

  According to the present invention, even in a link disconnection-tolerant network, in a place where there is a low possibility that other wireless terminals exist, it is possible to improve the wireless terminal's startup time interval by increasing the communication interface activation time interval. Reduces power consumption and extends battery life. On the other hand, in a place where there is a high possibility that another wireless terminal exists, discovery of another wireless terminal can be accelerated by shortening the activation time interval of the communication interface.

  Various changes, modifications, and omissions of the above-described various embodiments of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 1 Wireless terminal 100 Communication IF timer 101 Communication interface 102 Communication interface starting control part 103 Communication wireless environment change detection part 104 Carrier sense part 105 Link connection request transmission part 106 Link connection response reception part 107 Link connection process part 110 Broadcast IF timer 111 Broadcast Interface 112 Broadcast Interface Activation Control Unit 113 Broadcast Radio Environment Change Detection Unit 114 Failure Counter Unit

Claims (15)

In a start control method of a communication interface in a wireless terminal,
A wireless environment measurement step of measuring a wireless environment variation value associated with a variation in wireless quality, and setting a first timer value to the first timer based on the wireless environment variation value; 1 timer value is repeated,
A first step of activating the communication interface for a predetermined time when the first timer times out;
A second step of measuring a reception level in a predetermined frequency band transmitted from another wireless terminal and executing a link connection sequence for the other wireless terminal when the reception level is higher than a predetermined threshold;
A third step of transmitting a radio wave including a link connection request when the reception level is a predetermined threshold value or less;
When a link connection response is received from another wireless terminal, a link connection sequence is executed with the wireless terminal, and when the link connection response is not received for a predetermined time or more, the communication interface is stopped. And a step of controlling the activation of the wireless communication interface. In a start control method of a communication interface in a wireless terminal,
A wireless environment measurement step of measuring a wireless environment variation value associated with a variation in wireless quality, and setting a first timer value to the first timer based on the wireless environment variation value; 1 timer value is repeated,
A first step of activating the communication interface for a predetermined time when the first timer times out;
A second step of transmitting a radio wave including a link connection request;
A third step of measuring a reception level in a predetermined frequency band transmitted from another wireless terminal, and executing the link connection sequence for the other wireless terminal when the reception level is higher than a predetermined threshold;
When the reception level is below a predetermined threshold, when a link connection response is received from another wireless terminal, a link connection sequence is executed with the wireless terminal, and the link connection response cannot be received for a certain time or more. And a fourth step of stopping the communication interface when the communication interface is activated.   The wireless environment variation value in the wireless environment measurement step is based on a reflected wave with respect to a radio wave including the link connection request transmitted by the wireless terminal using the communication interface. The start control method of the radio | wireless communication interface of 1 or 2.   The wireless communication interface activation control method according to claim 1 or 2, wherein, in the wireless environment measurement step, the wireless environment fluctuation value is based on a broadcast radio wave received using a broadcast interface.   In the wireless environment measurement step, the larger the wireless environment variation value, the shorter the first timer value is set, and the smaller the wireless environment variation value, the longer the first timer value is set. The method for controlling activation of a wireless communication interface according to any one of claims 1 to 4. In a start control method of a communication interface in a wireless terminal,
The wireless terminal is
A broadcast interface for receiving radio waves for broadcast;
A first timer that repeats timing of the first timer value;
A second timer that repeats timing of the second timer value;
Have
When the second timer times out, start the broadcast interface,
Measure the radio environment fluctuation value for broadcasting accompanying the radio quality fluctuation of the broadcasting radio wave,
A second timer value corresponding to the broadcast radio environment fluctuation value is set in the second timer;
Set the first timer value corresponding to the failure counter to the first timer,
Stop the broadcast interface
Wireless environment measurement step;
A first step of activating the communication interface for a predetermined time when the first timer times out;
A reception level in a predetermined frequency band transmitted from another wireless terminal is measured via the communication interface, and when the reception level is higher than a predetermined threshold, a link connection sequence is executed for the other wireless terminal. Two steps,
A third step of transmitting a radio wave including a link connection request via the communication interface when the reception level is a predetermined threshold value or less;
When a link connection response from another wireless terminal is received via the communication interface, a link connection sequence is executed with the other wireless terminal, and the failure counter is reset, while the link connection is performed. A fourth step of stopping the communication interface and incrementing a failure counter by 1 when a response is not received for a certain period of time;
No line activation control method for a communication interface you further comprising a. The second timer value is set shorter as the broadcast radio environment variation value is larger, and the second timer value is set longer as the broadcast radio environment variation value is smaller.
The start of the wireless communication interface according to claim 6, wherein the first timer value is set shorter as the failure counter increases, and the first timer value is set longer as the failure counter decreases. Control method.   The link between other wireless terminals is controlled by a protocol for a link disconnection resistant network (DTN (Delay, Disruption, Disconnect Tolerant Network)), according to any one of claims 1 to 7. An activation control method for the wireless communication interface according to the description. In a wireless terminal having a communication interface,
A wireless environment fluctuation measuring means for measuring a wireless environment fluctuation value associated with a change in wireless quality;
First timer means for setting the first timer value to the first timer based on the wireless environment fluctuation value and repeating the counting of the first timer value;
Communication interface activation control means for activating the communication interface for a predetermined time when the first timer times out;
Carrier sense means for measuring a reception level in a predetermined frequency band transmitted from another wireless terminal;
Link connection request transmission means for transmitting radio waves including a link connection request after starting the communication interface or when the reception level is a predetermined threshold value or less;
Link connection response receiving means for receiving a link connection response from another wireless terminal, and when the reception level is higher than a predetermined threshold, or when a link connection response from another wireless terminal is received, Link connection processing means for executing a link connection sequence for
The wireless terminal characterized in that the communication interface activation control means stops the communication interface when the link connection response is not received for a predetermined time or more.   The wireless terminal according to claim 9, wherein the wireless environment variation value is based on a reflected wave with respect to a radio wave including the link connection request transmitted by the wireless terminal using the communication interface.   The wireless terminal according to claim 9, wherein the wireless environment fluctuation value is based on broadcast radio waves received using a broadcast interface.   12. The first timer value is set shorter as the wireless environment variation value is larger, and the first timer value is set longer as the wireless environment variation value is smaller. The wireless terminal according to claim 1. In a wireless terminal having a communication interface,
A broadcast interface for receiving radio waves for broadcast;
First timer means for setting the first timer value corresponding to the failure counter to the first timer and repeating the time measurement of the first timer value ;
A broadcast radio environment change detecting means for measuring a radio environment change value for broadcasting due to variation in radio quality before Symbol broadcast wave,
Set the second timer value corresponding to a radio environment change value before Symbol broadcast to the second timer, the second timer means for repeatedly counting the second timer value,
Broadcast interface activation control means for activating the broadcast interface when the second timer times out, and stopping the broadcast interface after measuring the radio environment fluctuation value for broadcasting;
Communication interface activation control means for activating the communication interface for a predetermined time when the first timer times out;
Carrier sense means for measuring a reception level in a predetermined frequency band transmitted from another wireless terminal via the communication interface;
Link connection request transmission means for transmitting a radio wave including a link connection request via the communication interface after starting the communication interface or when the reception level is a predetermined threshold value or less,
Link connection response receiving means for receiving a link connection response from another wireless terminal and when the reception level is higher than a predetermined threshold, or when a link connection response from another wireless terminal is received via the communication interface A link connection processing means for executing a link connection sequence with another wireless terminal, and on the other hand, stopping the communication interface when the link connection response is not received for a predetermined time or more;
A failure counter means for incrementing a failure counter by 1 when the link connection response is not received, and resetting the failure counter when a link connection sequence is executed with another wireless terminal; ,
The wireless terminal characterized in that the communication interface activation control means stops the communication interface when the link connection response is not received for a predetermined time or more.   The wireless communication according to any one of claims 9 to 13, wherein the link connection processing means controls a link with another wireless terminal by a protocol for a link disconnection resistant network (DTN). Terminal. In a program for causing a computer mounted on a wireless terminal having a communication interface to function,
A wireless environment fluctuation measuring means for measuring a wireless environment fluctuation value associated with a change in wireless quality;
First timer means for setting the first timer value to the first timer based on the wireless environment fluctuation value and repeating the counting of the first timer value;
Communication interface activation control means for activating the communication interface for a predetermined time when the first timer times out;
Carrier sense means for measuring a reception level in a predetermined frequency band transmitted from another wireless terminal;
Link connection request transmission means for transmitting radio waves including a link connection request after starting the communication interface or when the reception level is a predetermined threshold value or less;
Link connection response receiving means for receiving a link connection response from another wireless terminal, and when the reception level is higher than a predetermined threshold, or when a link connection response from another wireless terminal is received, Link connection processing means for executing a link connection sequence for
The communication interface activation control means causes a computer to function so as to stop the communication interface when the link connection response is not received for a predetermined time or longer.

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