JP4890476B2 - Communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication terminal which can suppress a decrease in the speed of the entire network and can reduce power consumption in a hub terminal by reducing the probability of collision of ATIMs in the hub terminal. <P>SOLUTION: The communication terminal is equipped with: a WLAN signal processing section 11, a WLAN protocol processing section 16, and a WLAN control section 19, which connect to and perform communications with a wireless base station of an infra-network; an EV-DO signal processing section 12, an EV-DO protocol processing section 17, and an EV-DO control section 20, which perform ad-hoc communications; and a storage section 14 for storing a standard ATIM window value and a reduced ATIM window value. When the infra-network communication section connects to the wireless base station, the ad-hoc communication section sets the ATIM window thereof to the reduced ATIM window value and includes, in a beacon, information indicating that the communication terminal is currently connected to the wireless base station. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a communication terminal that connects an infrastructure network (infrastructure network) and an ad hoc network (ad hoc network) as a hub terminal.

Conventionally, a network configuration for connecting an infrastructure network and an ad hoc network is known.
FIG. 17 is an explanatory diagram showing a network configuration for connecting a conventional infrastructure network and an ad hoc network. As shown in FIG. 17, the mobile devices 1a to 1d support wireless local area network (WLAN) ad hoc communication and EV-DO / 1x communication system, and have two systems of wireless communication units (RF). This is a terminal capable of simultaneous communication between WLAN and EV-DO / 1x.

The mobile device 1 a exists in the area 3 of the EV-DO base station 2 and communicates with the carrier network (infrastructure network) 4. Since the mobile devices 1b to 1d are located in the EV-DO / 1x out-of-service area, they communicate with the mobile device 1a by WLAN ad hoc communication. At this time, the mobile device 1a operates as a hub terminal that delivers communication of the mobile devices 1b to 1d connected by WLAN ad hoc to the infrastructure network 4 via EV-DO communication.
Next, a normal power saving mode in WLAN ad hoc communication will be described.
FIG. 18 is an explanatory diagram showing an outline of operation in WLAN ad hoc communication. As shown in FIG. 18, three of the mobile devices 1a to 1c are operating in the power saving mode, and the mobile device 1a sends out beacons at regular intervals. In the WLAN ad hoc mode, any mobile device that emits a beacon may be used, which is basically a first-come-first-served basis.

A certain period from the beginning of the beacon interval is referred to as an Annunciation Traffic Indication Message (ATIM) window, and during this period, an active state is maintained so that all mobile devices can receive the ATIM. When the mobile device wishes to perform data transmission, it transmits notification of data transmission after the ATIM window by transmitting the ATIM to the target mobile device within the ATIM window. The data is transmitted after the ATIM window ends.

  The mobile device that has received the ATIM does not enter the sleep state even after the ATIM window has passed, and remains in the active state until transmission data is received. When data is received, an ACK (ACKnowledge) is returned and a transition is made to sleep. However, an appropriate calculation method is not particularly defined for the size of the ATIM window, and if the size is too large, the active state is prolonged, so that unnecessary power consumption increases, and if the size is too small, an ATIM is transmitted. Since the period is shortened, it is waited until the next ATIM window.

  As a method for changing the ATIM window, there is “power management using an adaptive ATIM window in IEEE802.11IBSSWLAN” (see Patent Document 1). In the conventional “power management using an adaptive ATIM window in IEEE 802.11 IBS SWLAN”, the following method is used to appropriately determine the ATIM window.

When transmitting from a mobile station, transmission data is buffered if transmission is not possible within the ATIM window, and the ATIM window is lengthened when the number of buffers increases. When the ATIM is transmitted from the mobile device, if the place where the ATIM is transmitted from the end of the ATIM window is empty, the ATIM window is shortened. The ATIM window size is periodically updated by being embedded in the beacon.
JP-T-2006-519541

However, in the case of a network configuration that connects a conventional infrastructure network and an ad hoc network (see FIG. 17), the mobile device 1a uses two types of RF, WLAN RF and EV-DO / 1x RF at the same time. Compared with other mobile devices (1b to 1d) using the power consumption, the power consumption is extremely high.
Further, in the conventional “power management using an adaptive ATIM window in IEEE802.11IBSSWLAN” (see Patent Document 1), the ATIM window is optimized with priority on the execution speed, and thus power saving is not considered. As a result, the battery consumption increases and the power is turned off. As a result, the mobile device in communication via WLAN ad hoc cannot communicate.

Here, an ATIM collision in a network configuration (see FIG. 17) connecting a conventional infrastructure network and an ad hoc network will be described.
FIG. 19 is an explanatory diagram of ATIM collision in a network configuration connecting a conventional infrastructure network and an ad hoc network. As illustrated in FIG. 19, consider a situation in which the mobile device 1b transmits data to the mobile device 1a and the mobile device 1c transmits data to mobile devices other than the mobile devices 1a, 1b, and 1c during the power saving operation. The mobile device 1b transmits an ATIM to the mobile device 1a. The mobile device 1c also transmits the ATIM to another mobile device.

  However, when the mobile device 1a exists within the reach range of the ATIM transmitted by the mobile device 1c, the ATIM transmitted by the mobile device 1c also reaches the mobile device 1a. Then, the transmission timings of the ATIMs of the mobile device 1b and the mobile device 1c overlap, and both ATIMs collide and do not reach the transmission destination. The fact that the ATIM did not reach the transmission destination is detected because the ATIM ACK is not returned, so retransmission is attempted at the next timing.

If the frequency of occurrence of ATIM retransmission caused by this ATIM collision at a hub terminal (mobile device) where traffic is concentrated is high, the hub terminal becomes a bottleneck, which causes a decrease in throughput of the entire network. Although there is a possibility, the conventional “power management using an adaptive ATIM window in IEEE802.11IBSSWLAN” (see Patent Document 1) is not considered at all.
An object of the present invention is to provide a communication terminal that can reduce the probability of collision of ATIM in a hub terminal, suppress the influence of the speed reduction on the entire network, and reduce power consumption in the hub terminal. is there.

In order to achieve the above object, a communication terminal according to the present invention includes an infrastructure network communication unit that performs communication by connecting to a radio base station of an infrastructure network, an ad hoc communication unit that performs ad hoc communication, and a standard ATIM (Announcement Traffic Indication Message). ) A storage unit for storing a window value and a reduced ATIM window value, and the ad hoc communication unit uses the reduced ATIM window value when the infrastructure network communication unit is connected to the wireless base station. The ATIM window of the communication unit is set, and information indicating that the own terminal is a hub terminal is included in the beacon.

The communication terminal according to the present invention includes an ad hoc communication unit that performs ad hoc communication, and a storage unit that stores a standard ATIM window value and a reduced ATIM window value, and a beacon terminal received by the beacon received by the ad hoc communication unit Is included, the ad hoc communication unit sets an ATIM window used for communication with the communication terminal that is the transmission source of the beacon with the reduced ATIM window value. .

In the present invention, when the ad hoc communication unit receives a new beacon during connection with the hub terminal , the ad hoc communication unit uses the ATIM window used for communication with the communication terminal that is the transmission source of the new beacon. It is preferable to set a value obtained by subtracting the reduced ATIM window value from the standard ATIM window value.

  According to the present invention, the collision of ATIM at the hub terminal is distributed to mobile stations adjacent to the hub terminal, the probability of ATIM collision at the hub terminal is reduced, and the influence of the speed reduction on the entire network is suppressed. Since the ATIM collision is dispersed, the time for the hub terminal to be in the active state is shortened, and the power consumption of the hub terminal can be reduced.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a functional block diagram showing a schematic configuration of a communication terminal according to an embodiment of the present invention. As shown in FIG. 1, a mobile device (communication terminal) 10 includes a WLAN signal processing unit 11, an EV-DO signal processing unit 12, a control unit (Central Processing Unit: CPU) 13, a storage unit 14, and an input / output unit 15. have.
The WLAN signal processing unit 11 processes the WLAN signal, and the EV-DO signal processing unit 12 processes the EV-DO signal. The control unit 13 implements various functional elements by executing a control program or the like stored in the storage unit 14. The input / output unit 15 includes information input means such as various operation keys and information output means including a display screen such as a liquid crystal display.

The storage unit 14 also stores a standard ATIM window value and a window value for hub terminals (reduced ATIM window value).
FIG. 2 is a functional block diagram showing a schematic configuration of the control unit of FIG. As illustrated in FIG. 2, the control unit 13 includes a WLAN protocol processing unit 16, an EV-DO protocol processing unit 17, and a communication control unit 18. The communication control unit 18 includes a WLAN control unit 19 and an EV-DO control unit 20. The WLAN control unit 19 includes an EV-DO communication detection unit 21, a hub terminal detection unit 22, an ad hoc configuration unit 23, and power saving. The processing unit 24, the timing adjustment unit 25, and the ATIM window calculation unit 26, and the EV-DO control unit 20 each include an out-of-service determination processing unit 27.

  As shown in FIGS. 1 and 2, in the mobile device 10, the WLAN signal input via the antenna 11 a is input to the communication control unit 18 via the WLAN signal processing unit 11 and the WLAN protocol processing unit 16. The EV-DO signal input via the antenna 12 a is input to the communication control unit 18 via the EV-DO signal processing unit 12 and the EV-DO protocol processing unit 17. Also, the WLAN signal output processed in the communication control unit 18 is output via the antenna 11 a via the WLAN protocol processing unit 16 and the WLAN signal processing unit 11, and the EV-DO signal output in the communication control unit 18. Is output via the antenna 12a via the EV-DO protocol processing unit 17 and the EV-DO signal processing unit 12.

In the WLAN control unit 19, the EV-DO communication detection unit 21 detects that it is in the EV-DO communication state, the hub terminal detection unit 22 detects a mobile device to be a hub terminal, and the ad hoc configuration unit 23 The WLAN ad hoc communication is configured, the power saving processing unit 24 performs power saving processing, the timing adjustment unit 25 adjusts timing, and the ATIM window calculation unit 26 calculates an ATIM window. In the EV-DO control unit 20, the out-of-service determination processing unit 27 determines that the mobile device 10 is out of the EV-DO / 1x communication range. The ATIM window calculated by the ATIM window calculation unit 26 is stored in the storage unit 14.
As described above, the mobile device 10 supports the WLAN ad hoc communication and the EV-DO / 1x communication system, and has two wireless communication units, thereby enabling simultaneous communication of WLAN and EV-DO / 1x.

  FIG. 3 is an explanatory diagram showing an outline of operation in the power saving mode in the mobile device of FIG. As shown in FIG. 3, for example, three mobile devices 10a to 10c are operating in the power saving mode, and the mobile device 10a transmits beacons at equal intervals. During the period of the ATIM window, all mobile stations maintain an active state so that they can receive the ATIM, and when the mobile station wants to transmit data, the ATIM is transmitted to the target mobile station within the ATIM window. , Notify that data transmission is performed after the ATIM window. The data is transmitted after the ATIM window ends.

  The mobile device 10b that has received the ATIM from the mobile device 10a does not transition to the sleep state even after the ATIM window has passed, and maintains the active state until data from the mobile device 10 is received. When the data is received, an ACK (ACKnowledge) is returned to the mobile device 10a and a transition is made to sleep.

  Here, when the mobile device 10b detects that the mobile device 10a is a hub terminal, the mobile device 10b applies an ATIM window for the hub terminal that is shorter than the normal ATIM window. As an example, the length of the ATIM window for the hub terminal is about ½ of the length of the normal ATIM window. Within the ATIM window for the hub terminal having a length approximately half of the normal length, the ATIM between the hub terminal (here, the mobile station 10a) and the mobile station other than the hub terminal (here, the mobile stations 10b and 10c). In the period excluding the ATIM window for the hub terminal from the normal ATIM window, data transmission / reception between mobile devices other than the hub terminal, that is, ATIM transmission / reception is performed.

Thus, since the ATIM window for the hub terminal is shorter than the normal ATIM window, the active state when there is no communication data is shortened, so that the power consumption of the hub terminal is suppressed.
At this time, the mobile device other than the hub terminal must be able to detect whether the destination is the hub terminal when it transmits data. Therefore, when constructing a WLAN ad hoc network, the hub terminal embeds itself as a hub terminal using an unused field of the beacon and notifies a mobile device requesting a WLAN ad hoc connection.

  4 to 6 show a state in which information indicating a hub terminal is embedded in an unused field of the beacon. FIG. 4 shows information elements included in the beacon signal. As shown in the figure, the beacon signal includes an SSID (Service Set ID) field, a Capability information field, an ATIM information field, and the like.

  FIG. 5 shows information elements included in the Capability information field. The Capability information field includes an ATIM information include field indicating whether or not the ATIM information field is included in the beacon signal. The value of the ATIM information include field is 1 when the ATIM information field is included in the beacon signal. On the other hand, the value of the ATIM information include field is 0 when the ATIM information field is not included in the beacon signal.

FIG. 6 shows information elements included in the ATIM information field. The ATIM information field includes a Hubstation field, an ATIM Window field, and an ATIM Window for Hubstation field. The field length of each field is 8 bits.
Here, the three fields included in the ATIM information field shown in FIG. 6 are generated by the hub terminal (mobile device 10a). The mobile devices 10b and 10c can store the three fields shown in FIG. 6 received from the mobile device 10a in the ATIM information field.
Next, a case where the mobile device 10a starts EV-DO communication and the mobile devices 10b and 10c are connected to the mobile device 10a by WLAN ad hoc communication will be described.

FIG. 7 is a sequence chart illustrating a communication operation between a mobile device that is a hub terminal and a mobile device other than the hub terminal. As shown in FIG. 7, first, the mobile device 10a, which is a hub terminal, establishes an EV-DO session with, for example, the base station 28 and starts communication in the EV-DO area (step S11). .
Next, the mobile device 10b starts communication by EV-DO / 1x (step S12). However, since the mobile device 10b has detected that it is out of the EV-DO range (step S13), it attempts a WLAN ad hoc search. The mobile device 10a that has received the WLAN ad hoc search by the mobile device 10b sets only the ATIM window value for hub terminal transmission / reception (step S14).

  As a result of the WLAN ad hoc search, when the mobile device 10b detects the mobile device 10a (step S15), the mobile device 10a becomes a hub terminal based on information (hub terminal information) embedded in the WLAN frame sent from the mobile device 10a. It can be confirmed. By confirming that the mobile device 10a is a hub terminal, the mobile device 10b sets an ATIM window value for transmission / reception of the hub terminal and a normal ATIM window value for transmission / reception to other mobile devices (other than the hub terminal). (Step S16). As a result, a WLAN ad hoc session is established between the mobile device 10a and the mobile device 10b.

Furthermore, the mobile device 10c starts communication by EV-DO / 1x (step S17). However, since the mobile device 10c has detected that it is out of the EV-DO range (step S18), it attempts a WLAN ad hoc search. As a result of the search, when the mobile device 10c detects the mobile device 10b (step S19), it can be confirmed from the information embedded in the WLAN frame (no hub terminal information) that the mobile device 10b is not a hub terminal.
By confirming that the mobile device 10b is not a hub terminal, the mobile device 10c sets a value (ATIM window value) for a period obtained by subtracting the hub terminal ATIM window value from the ATIM window value (step S20). As a result, a WLAN ad hoc session is established between the mobile device 10b and the mobile device 10c, whereby the mobile devices 10b and 10c are connected to the infrastructure network via the mobile device 10a.

At this time, when transmitting data to the mobile device 10a, the mobile device 10b transmits an ATIM within the ATIM window for the hub terminal, and transmits data to the mobile device 10c from the normal ATIM window. ATIM is transmitted in a period excluding the terminal ATIM window.
Here, the dispersion of the collision probability of ATIM will be described.
Between the mobile device 10a and the mobile device 10b, since an ATIM window used only for data transmission / reception with the hub terminal is used, a mobile device other than the mobile device 10b transmits to the mobile device other than the mobile device 10a. Collisions are avoided.

Between the mobile device 10b and the mobile device 10c, the mobile device 10b transmits an ATIM in a period excluding the hub terminal ATIM window from the normal ATIM window, so that collision of the ATIM from the hub terminal is avoided.
However, since the ATIM window value that can be used in each mobile station decreases, it is expected that the collision probability of ATIM will increase to some extent.
From the above, it can be avoided that the ATIM collision probability of the hub terminal is distributed to the mobile devices other than the hub terminal (mobile devices 10b and 10c), and the hub terminal mobile device becomes a bottleneck state.

8 to 16 are flowcharts (Nos. 1 to 9) for explaining a communication operation between a mobile device that is a hub terminal and a mobile device other than the hub terminal.
FIG. 8 shows an operation when the mobile device 10a starts EV-DO communication and the mobile device 10b is connected by WLAN ad hoc communication. As shown in FIG. 8, first, the mobile device 10a starts EV-DO communication (step S101). Thereafter, the mobile device 10a starts loop processing, and sets the hub terminal ATIM window, the normal ATIM window, and the hub terminal information in the beacon (step S102). After the setting, the WLAN ad hoc is searched (beacon transmission periodically) (step S103), and it is determined whether or not a mobile device is newly detected (step S104).

As a result of the determination, when a new mobile station is detected (Yes), a WLAN ad hoc session is established (step S105), an ATIM window for the hub terminal is set (step S106), and the loop processing is terminated. On the other hand, when a new mobile device is not detected (No), the loop process is terminated as it is, and the connection operation is terminated.
FIG. 9 shows an operation when data is transmitted to the mobile device 10b while the mobile device 10a is operating as a hub terminal. As shown in FIG. 9, first, the mobile device 10a determines whether there is transmission data (step S201). As a result of the determination, when there is transmission data (Yes), the mobile device 10a transmits an ATIM within the hub terminal ATIM window (step S202). On the other hand, when there is no transmission data in step S201 (No), the mobile device 10a ends the process without performing the transmission operation.

  FIG. 10 shows an operation when the mobile device 10a receives data from the mobile device 10b while operating as a hub terminal. As shown in FIG. 10, the mobile device 10a first determines whether or not there is an ATIM addressed to itself in the hub terminal ATIM window (step S301). As a result of the determination, if there is an ATIM addressed to itself (Yes), data reception is performed (step S302), and then the process is terminated. On the other hand, when there is no ATIM addressed to itself (No), the mobile device 10a ends the process without performing the receiving operation.

  FIG. 11 shows an operation when the mobile device 10b connects to the mobile device 10a by WLAN ad hoc communication. As shown in FIG. 11, the mobile device 10b first starts communication by EV-DO / 1x (step S401), and detects that it is out of the EV-DO range (step S402). Thereafter, the mobile device 10b searches for a WLAN ad hoc (waits for reception of a beacon) (step S403), and determines whether a new mobile device is detected (whether a beacon is received) (step S404). .

  As a result of the determination, when a new mobile device is detected (beacon is received) (Yes in step S404), the mobile device 10b acquires the hub terminal ATIM window, the ATIM window, and the hub terminal information from the beacon (step S405). Thereafter, the mobile station 10b establishes a WLAN ad hoc session (step S406), sets a hub terminal ATIM window (step S407), and then subtracts the hub terminal ATIM window from the normal ATIM window. A terminal ATIM window is set (step S408). Subsequently, the hub terminal ATIM window and the normal ATIM window are set in the beacon (step S409), and the loop processing is terminated.

  On the other hand, as a result of the determination in step S404, when a new mobile device is not detected (a beacon is not received) (No in step S404), the mobile device 10b ends the loop process. The loop processing in this flowchart is continued during the normal ATIM window period, and the connection operation is terminated after the normal ATIM window period ends.

  FIG. 12 shows an operation when the mobile device 10b performs data transmission. As illustrated in FIG. 12, the mobile device 10b first determines whether there is transmission data (step S501). As a result of the determination, if there is transmission data (Yes), the mobile station 10b determines whether or not the destination is a hub terminal (step S502). If the destination is not a hub terminal (No) as a result of the determination, a normal ATIM The ATIM is transmitted during the period obtained by subtracting the hub terminal ATIM window from the window (step S503), and the transmission operation is terminated. On the other hand, when the destination is the hub terminal (Yes), the ATIM is transmitted in the hub terminal ATIM window (step S504), and then the transmission operation is terminated.

On the other hand, as a result of determining whether there is transmission data (step S501), if there is no transmission data (No), the mobile device 10b ends the transmission operation as it is.
FIG. 13 shows an operation when the mobile device 10b receives data. As shown in FIG. 13, the mobile device 10b first determines whether or not there is an ATIM addressed to itself in the hub terminal ATIM window (step S601). As a result of the determination, if there is no ATIM addressed to itself (No), it is determined whether or not there is an ATIM addressed to itself within the period excluding the hub terminal ATIM window from the ATIM window (step S602).

  On the other hand, as a result of determining whether or not there is an ATIM addressed to itself in the hub terminal ATIM window (step S601), it is determined whether or not the partner is the hub terminal (step S601). S603) If the result of determination is that the partner is a hub terminal (Yes), data is received (step S604). On the other hand, if the other party is not a hub terminal (No), no data is received. Subsequently, it is determined whether or not there is an ATIM addressed to itself within a period excluding the hub terminal ATIM window from the ATIM window (step S602).

  If the result of determination in step S702 is that there is no ATIM addressed to itself (No), the mobile device 10b ends the receiving operation. On the other hand, when there is an ATIM addressed to itself (Yes), the mobile device 10b determines whether or not the partner is other than the hub terminal (step S605). As a result of the determination, if the partner is other than the hub terminal (Yes), After receiving the data (step S606), the receiving operation is terminated. On the other hand, when the other party is not a hub terminal (No), the mobile device 10b ends the process without performing the reception operation.

  FIG. 14 shows an operation when the mobile device 10c connects to the mobile device 10b (or another mobile device other than the hub terminal) by WLAN ad hoc communication. As shown in FIG. 14, the mobile device 10c first starts communication by EV-DO / 1x (step S701), and detects that it is out of the EV-DO range (step S702). Thereafter, the mobile device 10c searches for WLAN ad hoc (waits for reception of a beacon) (step S703), and determines whether a new mobile device is detected (whether a beacon is received) (step S704). .

  As a result of the determination, when a mobile device is newly detected (beacon is received) (Yes in step S704), the mobile device 10c acquires the hub terminal ATIM window and the ATIM window from the beacon (step S705). Thereafter, the mobile device 10c establishes a WLAN ad hoc session (step S706), subtracts the hub terminal ATIM window from the normal ATIM window, and sets an ATIM window for a terminal other than the hub terminal (step S708), and continues. Then, the ATIM window for the hub terminal and the normal ATIM window are set in the beacon (step S709), and the loop process is terminated.

On the other hand, as a result of the determination in step S704, if a new mobile device is not detected (a beacon is not received) (No in step S704), the mobile device 10c ends the loop process. The loop processing in this flowchart is continued during the normal ATIM window period, and the connection operation is terminated after the normal ATIM window period ends.
FIG. 15 shows an operation when the mobile device 10c performs data transmission. As illustrated in FIG. 15, the mobile device 10c first determines whether there is transmission data (step S801). As a result of the determination, if there is transmission data (Yes), ATIM transmission is performed within a period obtained by subtracting the hub terminal ATIM window from the normal ATIM window (step S708), and then the process ends. On the other hand, when there is no transmission data (No), the mobile device 10c ends the process without performing the transmission operation.

  FIG. 16 shows an operation when the mobile device 10c receives data. As shown in FIG. 16, the mobile device 10c first determines whether or not there is an ATIM addressed to itself within a period obtained by subtracting the hub terminal ATIM window from the normal ATIM window (step S901). As a result of the determination, if there is an ATIM addressed to the user (Yes), the data is received (step S902), and then the process ends. On the other hand, when there is no ATIM addressed to itself (No), the mobile device 10c ends the process without performing the receiving operation.

  As described above, the mobile device 10 includes an infrastructure network communication unit (the WLAN signal processing unit 11, the WLAN protocol processing unit 16, and the WLAN control unit 19) that performs communication by connecting to a wireless base station of the infrastructure network, and ad hoc communication. An ad hoc communication unit (EV-DO signal processing unit 12, EV-DO protocol processing unit 17, and EV-DO control unit 20), a standard ATIM window (normal ATIM window) value and a reduced ATIM window (normal ATIM) Storage unit 14 that stores a value shorter than the window (ATIM window for a hub terminal), and the ad hoc communication unit ad hoc with a reduced ATIM window value when the infrastructure network communication unit is connected to a radio base station. While setting the ATIM window of the communication unit, the radio base station It includes information indicating that is being connected to the beacon.

  Further, the mobile device 10 includes an ad hoc communication unit (EV-DO signal processing unit 12, EV-DO protocol processing unit 17, and EV-DO control unit 20) that performs ad hoc communication, and a standard ATIM window (normal ATIM window). A storage unit 14 for storing a value and a reduced ATIM window (ATIM window for a hub terminal shorter than a normal ATIM window) value, and being connected to a wireless base station of an infrastructure network in a beacon received by an ad hoc communication unit Is included, the ad hoc communication unit sets an ATIM window used for communication with the communication terminal (mobile device) that is the transmission source of the beacon with a reduced ATIM window value.

  The ad hoc communication unit (EV-DO signal processing unit 12, EV-DO protocol processing unit 17, and EV-DO control unit 20) communicates with a communication terminal (mobile device) connected to a wireless base station of the infrastructure network. When a new beacon is received during connection, the ATIM window used for communication with the communication terminal (mobile device) that is the transmission source of the new beacon is reduced from the standard ATIM window (normal ATIM window) value. (ATIM window for a hub terminal shorter than a normal ATIM window) A value obtained by subtracting a value is set.

That is, the mobile device (communication terminal) according to the present invention has the following functions.
(1) When the mobile device is a hub terminal that connects WLAN ad hoc and EV-DO infrastructure network, the ATIM window during power saving mode operation is reduced from the ATIM window of mobile devices other than the hub terminal, and ATIM is transmitted. To do.
(2) When the mobile device is a mobile device other than a hub terminal connecting the WLAN ad hoc and the EV-DO infrastructure network and connected to the hub terminal, the mobile device of the hub terminal is only connected within the reduced ATIM window. ATIM is transmitted / received, and ATIM is transmitted / received to a mobile device other than the hub terminal within a period excluding the ATIM window reduced from the ATIM window.

(3) When the mobile device is a mobile device other than the hub terminal that connects the WLAN ad hoc and the EV-DO infrastructure network, data transmission / reception is performed within a period excluding the ATIM window reduced from the ATIM window.
As a result, during the WLAN ad hoc power saving mode communication, the hub terminal provides an ATIM window period during which only the ATIM for the hub terminal can be transmitted and received, so that the ATIM collision probability at the hub terminal is transferred to the mobile station adjacent to the hub terminal. Disperse. Dispersion of ATIM collisions shortens the time for the terminal to be in an active state when collisions occur frequently, thereby reducing power consumption.

Thus, according to the present invention, the probability of collision of ATIMs is distributed to mobile stations adjacent to the hub terminal, thereby suppressing the influence of the speed reduction on the entire network and aiming at the power saving effect at the hub terminal. The ATIM window can be adjusted appropriately.
Although the present invention has been described with reference to the above-described embodiment, it is not limited to this embodiment. Therefore, what is implemented as a change aspect without deviating from the meaning of the present invention is also included.

It is a functional block diagram which shows schematic structure of the communication terminal which concerns on one embodiment of this invention. It is a functional block diagram which shows schematic structure of the control part of FIG. It is explanatory drawing which shows the operation | movement outline | summary in the power saving mode in the mobile device of FIG. It is explanatory drawing which shows the information element contained in a beacon signal. It is explanatory drawing which shows the information element contained in a Capability information field. It is explanatory drawing which shows the information element contained in an ATIM information field. It is a sequence chart explaining a communication operation between a mobile device that is a hub terminal and a mobile device other than the hub terminal. It is a flowchart (the 1) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is a flowchart (the 2) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is a flowchart (the 3) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is a flowchart (the 4) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is a flowchart (the 5) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is a flowchart (the 6) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is a flowchart (the 7) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is a flowchart (the 8) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is a flowchart (the 9) explaining the communication operation | movement between the mobile apparatus which is a hub terminal, and mobile apparatuses other than a hub terminal. It is explanatory drawing which shows the network structure which connects the conventional infrastructure network and an ad hoc network. It is explanatory drawing which shows the operation | movement outline | summary in WLAN ad hoc communication. It is explanatory drawing of the collision of ATIM in the network structure which connects the conventional infrastructure network and an ad hoc network.

Explanation of symbols

10, 10a to 10c Mobile station 11 WLAN signal processing unit 11a Antenna 12 EV-DO signal processing unit 12a Antenna 13 Control unit 14 Storage unit 15 Input / output unit 16 WLAN protocol processing unit 17 EV-DO protocol processing unit 18 Communication control unit 19 WLAN control unit 20 EV-DO control unit 21 EV-DO communication detection unit 22 Hub terminal detection unit 23 Ad hoc configuration unit 24 Power saving processing unit 25 Timing adjustment unit 26 ATIM window calculation unit 27 Out-of-service determination processing unit

Claims (3)

An infrastructure network communication unit that communicates with a wireless base station of an infrastructure network; and
An ad hoc communication unit for performing ad hoc communication;
A storage unit for storing a standard ATIM (Announcing Traffic Indication Message) window value and a reduced ATIM window value;
The ad hoc communication unit
When the infrastructure network communication unit is connected to the radio base station, the ATIM window of the ad hoc communication unit is set with the reduced ATIM window value, and information indicating that the own terminal is a hub terminal is used as a beacon. A communication terminal characterized by including. An ad hoc communication unit for performing ad hoc communication;
A storage unit for storing a standard ATIM window value and a reduced ATIM window value;
When the beacon received by the ad hoc communication unit includes information indicating that it is a hub terminal , the ad hoc communication unit uses the ATIM window used for communication with the communication terminal that is the transmission source of the beacon. A communication terminal which is set with a reduced ATIM window value. The ad hoc communication unit
When a new beacon is received while connected to the hub terminal , the ATIM window used for communication with the communication terminal that is the transmission source of the new beacon is subtracted from the standard ATIM window value. The communication terminal according to claim 2, wherein the communication terminal is set to a predetermined value.

Images