JP2014003581A - Communication device, method for controlling communication device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform power saving control according to the transmission interval of control information transmitted by another communication device.SOLUTION: A communication device includes: an acquisition unit for acquiring the transmission interval of control information transmitted by another communication device; and a transition unit for shifting the communication device, according to the transmission interval, to a power saving mode in which communication is switched between an awake state of receiving data from the other communication device and a doze state of not receiving data from the other communication device.

Description

  The present invention relates to a communication device, a communication device control method, and a program.

  In recent years, products equipped with wireless communication typified by wireless LAN compliant with the IEEE802.11 series are rapidly spreading. Products equipped with a wireless LAN include portable devices such as cameras and PDAs (Personal Digital Assistants). Many portable devices are battery powered, and power saving is one of the challenges for these products.

  In response to this problem, the IEEE 802.11 specification defines a power saving mode. In the power saving mode, there exist a doze state (a state where power supply to the transmission / reception circuit is stopped) and an awake state (a state where power is supplied to the transmission / reception circuit). These states are controlled so as to change according to the beacon interval of the network. Usually, a communication apparatus changes in a doze state, and performs power saving control by changing to an awake state when there is a timing at which an access point (AP) transmits a beacon or a packet to be transmitted / received.

  However, the doze state is a state in which power supply to the transmission / reception circuit is stopped, and thus transmission / reception of packets is impossible. It is necessary for the communication apparatus to grasp whether the own apparatus is currently in the doze state or the awake state, and when transmitting / receiving a packet, it is necessary to carry out after the transition to the awake state. Therefore, when the beacon interval of the connected network is short, the communication apparatus must perform power management mode state management at a short interval, and may not satisfy the control time constraint.

  In order to solve the above problem, in Patent Document 1, the communication I / F unit is turned on and off by a method other than the power saving mode defined in the IEEE 802.11 specification to reduce the power consumption of the communication device. A method to realize it has been proposed. Specifically, this is a technique for performing power saving control using a flow control mechanism in data communication.

International Publication No. 2008/032750

  However, in the communication device described in Patent Document 1, the communication device performs power saving control by a method other than the power saving mode defined in the IEEE 802.11 specification. Therefore, the AP to which the communication device is connected determines that the communication device is in an active mode (a state that is not in the power saving mode), and may transmit data at an arbitrary timing. There is a possibility of spilling. In addition, the communication device described in Patent Document 1 performs power saving control using a flow control mechanism in data communication. In order to use this mechanism, the communication partner device needs to be installed with the same software as the software installed in the communication device, so that there is a problem of lack of versatility.

  In view of the above problems, an object of the present invention is to implement power saving control according to the transmission interval of control information transmitted by another communication apparatus.

A communication device according to the present invention that achieves the above object is as follows.
Acquisition means for acquiring a transmission interval of control information transmitted by another communication device;
Transition means for shifting the communication device to a power saving mode for switching between an awake state in which data is received from the other communication device and a doze state in which data is not received from the other communication device in accordance with the transmission interval. When,
It is characterized by having.

  ADVANTAGE OF THE INVENTION According to this invention, power saving control according to the transmission interval of the control information which another communication apparatus transmits can be implemented.

The network block diagram concerning 1st Embodiment. The block block diagram of the communication apparatus which concerns on 1st Embodiment. The flowchart which shows the process sequence of the communication apparatus which concerns on 1st Embodiment. The flowchart which shows the process sequence of the communication apparatus which concerns on 2nd Embodiment. The flowchart which shows the process sequence of the communication apparatus which concerns on 3rd Embodiment.

(First embodiment)
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, when a communication apparatus operable in the power saving mode shifts to the power saving mode, the access point checks the interval at which the beacon is transmitted (this is referred to as the beacon interval), and the beacon interval is equal to or longer than a predetermined unit time. An example of shifting to the power saving mode in the case of

  FIG. 1 is a diagram illustrating a configuration of a network according to the first embodiment. The network includes a communication device 10 (STA) and an access point 11 (AP11), and the communication device 10 is connected to the AP 11 in the infrastructure mode. In the present embodiment, a case where a printer is used as the communication device 10 will be described as an example.

  FIG. 2 is a block diagram illustrating an example of the configuration of the communication device 10 according to the first embodiment. The communication device 10 includes an input unit 201, a control unit 202, an output unit 203, a storage unit 204, a communication unit 205, and a printing unit 206. The communication device 10 alternately repeats the awake state in which data is received from other communication devices and the doze state in which data is not received from other communication devices, and is synchronized with the transmission cycle of control information periodically transmitted from the AP 11. Thus, it is possible to execute a power saving mode in which communication is performed by switching the state of the communication device 10.

  The input unit 201 receives various inputs from the user. The input unit 201 can also accept settings related to the wireless LAN. The control unit 202 controls the operation of each component. The control unit 202 controls the communication unit 205 using the communication parameters stored in the storage unit 204, transmits / receives data to / from other devices via the communication unit 205, and performs connection processing to the wireless LAN network. It is possible to go. The output unit 203 performs various outputs (notifications) to the user through display output such as an LCD (Liquid Crystal Display) and LED (Light Emitting Diode), and audio output such as a speaker. Further, the output unit 203 outputs, for example, settings related to the wireless LAN received by the input unit 201. The storage unit 204 stores various information such as a computer program executed by the control unit 202 and communication parameters. The communication unit 205 communicates with other devices. The communication unit 205 performs processing related to communication such as processing related to MAC (Media Access Control) with respect to the received control information and data. In the present embodiment, the control information is a beacon transmitted by the AP 11. The control information transmission interval is a beacon interval acquired from a beacon. The printing unit 206 executes a printing process for data received through the communication unit 205.

  With reference to the flowchart of FIG. 3, the process procedure of the communication apparatus 10 which concerns on 1st Embodiment is demonstrated. More specifically, an operation when the communication apparatus 10 is connected to the infrastructure network configured by the AP 11 will be described.

  In S301, the communication device 10 performs a search process for an AP that is a connection destination when performing a connection process to an AP.

  In S302, the communication apparatus 10 determines whether a predetermined AP (AP11 in this embodiment) has been found. When it is determined that it has been found (S302; YES), the process proceeds to S303. On the other hand, when it is determined that it has not been found (S302; NO), the process returns to S301.

  In S303, the communication apparatus 10 performs a connection process to the discovered AP 11. In S304, the communication apparatus 10 determines whether the connection process is successful. When it is determined that the connection process is successful (S304; YES), the process proceeds to S305. On the other hand, when it is determined that the connection process has failed (S304; NO), the process returns to S303.

  In S <b> 305, the communication device 10 stores the connected network information in the storage unit 204. The network information to be stored includes SSID (Service Set Identifier), BSSID (Basic Service Set Identification), beacon interval, DTIM (Delivery Traffic Indication Message) interval, and the like.

  In S306, the communication device 10 is operating in the active mode (the state that is not the power saving mode). In S307, after connecting to the network, the communication apparatus 10 checks the power saving mode flag information stored in the storage unit 204 and determines whether or not the power saving mode flag is ON. Here, the power saving mode flag information is a flag for determining whether or not to shift from the active mode to the power saving mode when the communication apparatus 10 is connected to the AP (transferability determination information). Take OFF value. When the power saving mode flag is ON, it means an instruction to permit shifting to the power saving mode, so that the shifting process is performed, and when it is OFF, the shifting process to the power saving mode is not performed. The communication device 10 holds a value of ON or OFF as the initial value of the power saving mode flag. The user can also set a power saving mode flag (transition determination information) using the input unit 201.

  When it is determined that the power saving mode flag is ON (S307; YES), the process proceeds to S308. On the other hand, when it is determined that the power saving mode flag is OFF (S307; NO), the process is terminated without performing the process of shifting to the power saving mode. In S308, the communication apparatus 10 determines whether the beacon interval (control information transmission interval) transmitted by the AP 11 is equal to or longer than a predetermined unit time (a predetermined value). If it is determined that the beacon interval is equal to or longer than the predetermined unit time (predetermined value) (S308; YES), the process proceeds to S309. On the other hand, when it is determined that the beacon interval is less than the predetermined unit time (less than the predetermined value) (S308; NO), the process ends without performing the process of shifting to the power saving mode. In S309, the communication device 10 shifts to the power saving mode. Thereafter, the process ends.

  Here, the unit time is a unit of beacon transmission interval defined in the IEEE 802.11 specification, and one unit time is 1024 microseconds. The value of the predetermined unit time used in the determination in S308 is determined according to the processing capability of the communication device 10 and the degree of power saving effect that the communication device 10 requires.

  As described above, according to the present embodiment, the communication apparatus 10 determines a condition for enabling the transition to the power saving mode from the setting of the own apparatus and the information of the connected network, and shifts to the power saving mode. By shifting to the power saving mode only under possible conditions, it is possible to implement power saving control that is not constrained by the time constraint due to the short beacon interval. In the present embodiment, the case where the beacon transmitted by the AP 11 is used as an example of the method for the communication apparatus 10 to acquire the control information transmission interval has been described. However, the probe response (search response) transmitted by the AP 11 is used. The included control information transmission interval may be used. The probe response is a signal transmitted by the AP 11 when the AP 11 receives a probe request (search request) from the communication device 10.

  In this embodiment, the case where the connection destination AP search process (S301) is repeated until a predetermined AP is found in the connection destination AP search process (S302) has been described as an example. If a predetermined AP cannot be found even after performing the AP search process (S302), the process may be terminated.

  Further, in the present embodiment, the case where the connection process to the predetermined AP (S303) is repeated until the connection to the predetermined AP has been described as an example. However, the connection process (S303) to the AP a specified number of times including one is performed. Even if it is not possible to connect to a predetermined AP, the process may be terminated.

  Further, in the present embodiment, the case has been described as an example where the process is terminated without shifting to the power saving mode when the beacon interval transmitted by the AP is less than the predetermined unit time. In this case, the output unit 203 may be used to further notify the user that the user has failed to enter the power saving mode. Alternatively, the current communication mode may be notified to the user using the output unit 203 before the processing ends.

(Second Embodiment)
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The configuration of the network and the configuration of the communication device 10 according to the second embodiment are the same as those of the first embodiment described with reference to FIGS.

  A processing procedure of the communication apparatus 10 according to the second embodiment will be described with reference to the flowchart of FIG. In the present embodiment, when the communication device 10 is connected to the AP and is in the active mode, it is determined whether or not the state of the own device can be shifted to the power saving mode and the mode is shifted to the power saving mode. Is different.

  In S401, the communication apparatus 10 is operating in the active mode (a state that is not the power saving mode).

  In S402, the communication apparatus 10 determines whether or not the own apparatus is in a state where it can shift to the power saving mode. Here, the state that can be shifted to the power saving mode is a state in which a certain time has elapsed since the user operated the input unit 201, or a state in which another certain time has elapsed since the operation of the printing unit 206 was completed. Can be given. If it is determined that the power saving mode can be entered (S402; YES), the process proceeds to S403. On the other hand, when it is determined that the power saving mode cannot be entered (S402; NO), the system waits until the status becomes transitionable.

  In S403, the communication apparatus 10 checks the beacon interval stored in the storage unit 204 and determines whether the beacon interval is equal to or longer than a predetermined unit time. When it is determined that the beacon interval is equal to or longer than the predetermined unit time (S403; YES), the process proceeds to S404. On the other hand, when it determines with a beacon interval being less than predetermined unit time (S402; NO), a process is complete | finished, without implementing the transfer process to power saving mode. In S404, the communication apparatus 10 shifts its communication mode to the power saving mode. Thereafter, the process ends.

  As described above, according to the present embodiment, when the communication apparatus 10 is connected to the AP in the active mode, the communication apparatus 10 shifts to the power saving mode only when it is determined that it can shift from the state of the own apparatus to the power saving mode. By doing so, the control time constraint can be satisfied.

  In this embodiment, the user is not notified that the communication apparatus 10 has shifted to the power saving mode, but may be notified to the user using the output unit 203 that the communication apparatus 10 has shifted to the power saving mode. Good. Alternatively, the current communication mode may be notified to the user using the output unit 203 before the processing ends.

(Third embodiment)
Hereinafter, the third embodiment will be described in detail with reference to the accompanying drawings. The configuration of the network and the configuration of the communication device 10 according to the third embodiment are the same as those of the first embodiment described with reference to FIGS.

  With reference to the flowchart of FIG. 5, the process procedure of the communication apparatus 10 which concerns on 3rd Embodiment is demonstrated. In the present embodiment, when the communication device shifts to the power saving mode, the transmission interval of the beacon transmitted by the access point and the DTIM interval (access point (other communication device) included in the beacon are for a plurality of communication devices. An example of shifting to the power saving mode when the product of the beacon transmission interval and the DTIM interval is equal to or smaller than a predetermined value will be described. In the flowchart of FIG. 5, the processing from S301 to S308 is the same as the processing described in FIG.

  In S509, the communication device 10 obtains the product using the beacon interval and the DTIM interval from the network information stored in the storage unit 20, and when the value is determined to be equal to or less than the predetermined value (S509; YES), the process proceeds to S510. . On the other hand, when it is determined that the product of the beacon interval and the DTIM interval exceeds a predetermined value (S509; NO), the process is terminated without performing the process of shifting to the power saving mode. In S510, the communication device 10 shifts to the power saving mode. Thereafter, the process ends.

  Here, for example, the communication device 10 determines YES when the beacon interval transmitted by the AP 11 in S308 is 100 unit time or more, and YES when the product of the DTIM interval and the beacon interval is 500 or less in S509. I will explain.

  At this time, if the beacon interval is 100 and the DTIM interval is 5, the value of these products is 500, and the communication apparatus 10 shifts to the power saving mode in the determination of S509. On the other hand, if the beacon interval is 100 but the DTIM interval is 6, the communication device 10 does not enter the power saving mode according to the determination in S509. If the beacon interval is 90, the process ends without shifting to the power saving mode in the determination of S308 regardless of the value of the DTIM interval.

  The transmission timing of the multicast packet or broadcast packet transmitted by the AP 11 depends on the beacon interval and the DTIM interval. Therefore, as in this embodiment, by using the value of the beacon interval and the value of the DTIM interval for the determination to shift to the power saving mode, it is possible to prevent the reception of multicast packets and broadcast packets from being delayed for a predetermined time or more. .

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (7)

A communication device,
Acquisition means for acquiring a transmission interval of control information transmitted by another communication device;
Transition means for shifting the communication device to a power saving mode for switching between an awake state in which data is received from the other communication device and a doze state in which data is not received from the other communication device in accordance with the transmission interval. When,
A communication apparatus comprising:   The communication apparatus according to claim 1, wherein the shift unit shifts to the power saving mode when the transmission interval is equal to or greater than a predetermined value. A setting unit that allows a user to set whether or not to shift to the power saving mode;
The transition unit, when transition to the power saving mode is permitted by the setting unit, causes the communication apparatus to transition to the power saving mode according to the transmission interval. 2. The communication device according to 2.   A notification means for notifying the user that the power saving mode is not set when the setting means permits the shift to the power saving mode and the transmission interval is smaller than a predetermined value; The communication apparatus according to claim 3, further comprising: The control information includes a predetermined control information transmission interval at which the other communication device transmits data to a plurality of communication devices,
Further comprising obtaining means for obtaining the predetermined control information transmission interval from the control information;
3. The communication apparatus according to claim 1, wherein the shift unit does not shift to the power saving mode when a product value of the transmission interval and the predetermined control information transmission interval exceeds a predetermined value. 4. . A communication device control method comprising:
Acquiring a transmission interval of control information transmitted by another communication device;
According to the acquired transmission interval, the communication apparatus is shifted to a power saving mode in which communication is performed by switching between an awake state in which data is received from the other communication apparatus and a doze state in which data is not received from the other communication apparatus. Process,
A control method characterized by comprising:   The program for making a computer perform each process of the control method of the communication apparatus of Claim 6.

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