Patent Publication Number: US-9408017-B2

Title: Communication apparatus, control method, and storage medium

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a power saving technology for application in the case where a plurality of communication methods are available. 
     2. Description of the Related Art 
     In recent years, the number of mobile terminals equipped with a near field communication (NFC) function that is defined by the NFC Forum and can be used for settling accounts and the like have been increasing. Meanwhile, in order to transmit or receive large amounts of data, an increasing number of mobile terminals have wireless LAN communication functions conforming to the IEEE 802.11 standard, for example. 
     Increased power consumption is a problem when these wireless communication functions are left on all the time. In response to this, Japanese Patent Laid-Open No. 2008-283590 discloses a technology for suppressing power consumption of the wireless LAN function by using NFC to perform communication required to set up a wireless LAN connection. Also, Japanese Patent Laid-Open No. 2010-028753 discloses a technology that, in order to suppress power consumption by a proximity wireless communication function, provides the communication apparatus with a proximity detection function having lower power consumption than the wireless communication function, and returns the wireless communication function from a sleep state in the case where another apparatus is detected in proximity. Furthermore, Japanese Patent Laid-Open No. 2007-306201 discloses placing the wireless LAN function in the sleep state as a rule, in order to reduce power consumption when wireless LAN communication is not being performed, and activating the wireless LAN function of a partner apparatus using wireless communication having low power consumption in the case where data communication is required. 
     However, there is a problem with the technology disclosed in Japanese Patent Laid-Open No. 2007-306201 in that, in order for the communication function that uses wireless LAN to be activated, it is necessary to maintain a state in which communication by wireless communication having low power consumption is possible at all times. That is, placing the communication function that uses wireless LAN in the sleep state is premised on the wireless communication having low power consumption being in a communicable state, and no consideration whatsoever is given to the state of the wireless communication having low power consumption. 
     The present invention has been made in view of the above problem, and provides a power saving technology for an apparatus that is capable of using a plurality of communication methods. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, there is provided a communication apparatus having a first communication unit configured to periodically transmit a predetermined signal and communicate with another apparatus and a second communication unit configured to communicate with another apparatus by producing an electric field or magnetic field, comprising: a determination unit configured to determine whether a partner apparatus exists in a communicable range of the second communication unit; and a control unit configured to control the first communication unit to stop transmission of the predetermined signal in a case where it is determined that the partner apparatus exists in the communicable range. 
     According to one aspect of the present invention, there is provided a communication apparatus having a first communication unit configured to communicate wirelessly with another apparatus and a second communication unit configured to perform at least one of receive power reception from another apparatus or communicate communication with the other apparatus by an electric field or magnetic field produced by the other apparatus, comprising: a determination unit configured to determine whether the communication apparatus exists in a communicable range of a second third communication unit of the partner apparatus, which is corresponding to the second communication unit; and a control unit configured to control the first communication unit to enter a sleep state, in a case where it is determined that the communication apparatus exists in the communicable range. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing an exemplary configuration of a wireless communication system. 
         FIG. 2  is a block diagram showing an exemplary configuration of a first communication apparatus (STA). 
         FIG. 3  is a block diagram showing an exemplary configuration of a second communication apparatus (AP). 
         FIG. 4  is a flowchart showing first processing by the STA. 
         FIG. 5  is a flowchart showing second processing by the STA. 
         FIG. 6  is a flowchart showing third processing by the STA. 
         FIG. 7  is a flowchart showing fourth processing by the STA. 
         FIG. 8  is a flowchart showing first processing by the AP. 
         FIG. 9  is a flowchart showing second processing and fourth processing by the AP. 
         FIG. 10  is a flowchart showing third processing by the AP. 
         FIG. 11  is a first sequence diagram showing the flow of processing executed by the STA and the AP. 
         FIG. 12  is a second sequence diagram showing the flow of processing executed by the STA and the AP. 
         FIG. 13  is a third sequence diagram showing the flow of processing executed by the STA and the AP. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     An exemplary embodiment(s) of the present invention will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of the components, and the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. 
     System Configuration 
     An exemplary configuration of a wireless communication system according to the present embodiment is shown in  FIG. 1 . The wireless communication system includes, for example, as shown in  FIG. 1 , a first communication apparatus (STA  100 ), a second communication apparatus (AP  120 ), and a third communication apparatus (STA  140 ). In the present embodiment, the STA  100  and the AP  120  have a first communication function that uses wireless LAN and a second communication function that uses NFC (Near Field Communication), and communicate with each other as partner apparatuses. Note that AP denotes an access point in wireless LAN communication, and STA denotes a station (terminal) in wireless LAN communication. 
     The STA  100  and the AP  120  are able to communicate with each other using the first communication function, which conforms to the IEEE 802.11 standard, for example. Note that the STA  140  and the AP  120  may communicate wirelessly using the first communication function, or wired communication between the STA  140  and the AP  120  may be established via another AP, for example. 
     The AP  120  produces an electric field or magnetic field using the NFC function, and is able to at least one of communicate with the STA  100  and supply power to the STA  100 . Similarly, the STA  100  is able to at least one of communicate with the AP  120  and receive power that is supplied from the AP  120 , by using the electric field or magnetic field produced by the AP  120  using the NFC function. Note that it is possible for the STA  100  to be able to produce an electric field or magnetic field using an NFC function and communicate with the AP  120  or supply power to the AP  120 , and for the AP  120  to be able to communicate or receive power using the electric field or magnetic field produced by the STA  100 . Note that, unless stated otherwise, the NFC function is assumed to conform to the standards of the NFC Forum. 
     In the present embodiment, when the STA  100  and the AP  120  exist in the communicable range of the NFC function as a result of the STA  100  moving in proximity to the AP  120 , the STA  100  and the AP  120  perform control for causing the first communication function that uses wireless LAN to enter the sleep state. Note that the sleep state referred to here is a state in which the wireless LAN function is turned OFF in the STA  100 , and is, furthermore, a state in which the AP  120  does not periodically transmit a predetermined signal such as a beacon, and the beacon reception function in the STA  100  is also stopped. That is, since the STA  100  also does not perform periodical activation for waiting for a beacon as a result of causing the wireless LAN function to enter the sleep state, power consumption relating to wireless LAN can be greatly reduced. Also, the STA  100 , by also placing a control unit that controls the whole apparatus in the sleep state, enters a state in which only the NFC communication function can be driven. The NFC communication function, by being driven with power that is supplied from the AP  120 , greatly reduces power consumption for the apparatus as a whole, with zero power consumption being possible in some cases. 
     When the STA  100  moves out of the communicable range of the NFC function after the wireless LAN has entered the sleep state, the STA  100  and the AP  120  perform control so as to cancel the sleep state of the first communication function that uses wireless LAN and activate communication by wireless LAN. Also, when data addressed to the STA  100  reaches the AP  120  from the STA  140 , for example, after the wireless LAN has entered the sleep state, the AP  120  uses the NFC function to notify the STA  100  that there is data to be transmitted. The STA  100  and the AP  120  activate the wireless LAN communication function from the sleep state, and perform transmission and reception of the data. In the case where the STA  100  still exists in the communicable range of the NFC function of the AP  120  after transmission/reception of the data, the wireless LAN function is caused to enter the sleep state. 
     It thereby becomes possible for the STA  100  and the AP  120  to cause the wireless LAN communication function to enter the sleep state or to activate the wireless LAN communication function from the sleep state, according to whether the STA  100  exists within the communicable range of the NFC function of the AP  120 . Also, since it is possible to communicate using NFC when the wireless LAN communication function is in the sleep state, it is possible, in the case where there is data to be transmitted, to notify the partner apparatus that the data exists using the NFC function. Hereinafter, each apparatus that performs this processing and the processing that is executed will be described in detail. 
     Configuration of STA  100   
     An exemplary configuration of a first communication apparatus (STA  100 ) is shown in  FIG. 2 . The STA  100  has, for example, a timer  111 , a power storage unit  112 , and a common unit  110  of which the AP  120  has a similar function. Also, the common unit  110  has a control unit  101 , a storage unit  102 , a data processing unit  103 , an operation unit  104 , an output unit  105 , a power supply unit  106 , a wireless LAN functional unit  107 , and an NFC unit  108 . These functional units are connected, as shown in  FIG. 2 , by a bus  109  and other wirings  113  to  115 . 
     The control unit  101  is a functional unit that executes control programs stored in the storage unit  102 , and is constituted by a CPU or the like, for example. The storage unit  102  stores control programs that are executed by the control unit  101 , data for performing control, and the like. The storage unit  102  is constituted by a nonvolatile ROM, a volatile RAM, or the like. Controls discussed later are executed by the control unit  101  executing control programs stored in the storage unit  102 . The data processing unit  103  executes signal processing, calculations, clocking, and the like. The operation unit  104  is a functional unit that detects user operations, and consists of buttons, a mouse, a touch panel, and the like. The output unit  105  is constituted by a display, a speaker output, and the like. The power supply unit  106  supplies power to the functional units of the STA  100 . 
     The wireless LAN functional unit  107  is a functional unit for executing wireless LAN communication, and is, for example, a module consisting of an LSI, an antenna or the like that incorporates a control function relating to wireless LAN. The NFC unit  108  is a functional unit for executing NFC communication, and is, for example, a module consisting of an LSI, an antenna or the like that incorporates a control function relating to NFC. 
     The timer  111  is initialized (reset) by a confirmation signal (e.g., NFC polling) being received in the NFC unit  108  from a partner apparatus, and measures elapsed time after being reset. The timer  111  then gives an interrupt signal to the control unit  101 , in the case where the elapsed time that is measured exceeds a predetermined value. The power storage unit  112 , which is, for example, constituted by a capacitor, stores power received by the NFC unit  108  and continuously operates the timer  111 . 
     Configuration of AP  120   
       FIG. 3  shows an exemplary configuration of the second communication apparatus (AP  120 ). The AP  120  has, for example, a wired communication unit  121 , an AP functional unit  122 , and a common unit  110 . The wired communication unit  121  communicates using Ethernet™. The AP  120  is connected by a cable to a network, for example, and in the case where a signal is received from the network, that signal is received by the wired communication unit  121 . The AP functional unit  122  is a functional unit for executing the function of an access point that does not exist in the STA  100 . Note that the functions of the common unit  110  are common to the STA  100 . 
     The control unit  101  of the STA  100  operates while transitioning between the sleep state in which power is not consumed and an awake state in which power is consumed. The control unit  101  of the STA  100  transitions to the awake state upon receiving an event, an interrupt or the like in the sleep state. At this time, the control unit  101  of the STA  100  can be restored to the state immediately before entering the sleep state by loading settings information, for example. 
     The STA  100  also has a sleep state and an awake state, similarly to the control unit  101 , for the wireless LAN functional unit  107 . Note that the wireless LAN functional unit  107 , in the sleep state, is unable to transmit and receive signals, since the high frequency circuit for use in communication is stopped. Furthermore, in a general doze state, the reception circuit is operated according to a cyclic timer, but in the sleep state described hereinafter it is assumed that such a timer operation is also not executed. That is, it is assumed that the wireless LAN functional unit  107  does not have a function of autonomously operating the high frequency circuit, and is returned to the awake state by being activated by another functional unit. 
     Note that, hereinafter, description will be given assuming that the wireless LAN functional unit  107  of the STA  100  is in the sleep state but that the wireless LAN functional unit  107  of the AP  120  is not in the sleep state even though periodical transmission of a beacon is stopped. However, the wireless LAN functional unit  107  of the AP  120  may also be caused to enter the sleep state to realize a further reduction in the power consumption of the AP  120 . 
     Operations of STA  100   
     The processing that is executed by the STA  100  is broadly divided into four types of processing. The first processing is “processing from initial setup to entering sleep state”, the second processing is “routine processing in the sleep state”, the third processing is “processing when there is reception data”, and the fourth processing is “NFC departure detection and related processing”. Hereinafter, these four types of processing will be described using  FIGS. 4 to 7 , respectively. 
     1. Processing from Initial Setup to Entering Sleep State 
     The operation of the first processing is shown in  FIG. 4 . Note that at the time of starting the processing of  FIG. 4 , it is assumed that the STA  100  operates the NFC unit  108  in a two-way communication mode, and that the wireless LAN functional unit  107  is in a reception state. Also, it is assumed that the control unit  101  of the STA  100  is in an idle state of waiting for an event from the functional units. 
     Note that the NFC unit  108 , in the two-way communication mode, is able to perform at least one of communicating with a partner apparatus and supplying power to a partner apparatus by producing electromagnetic coupling itself. The two-way communication mode in NFC is also called active mode or reader/writer mode. Note that the NFC unit  108  is also able to operate in a passive mode. The NFC unit  108 , in the passive mode, is driven by electromagnetic coupling energy produced by a partner apparatus, and is able to perform at least one of communication and power reception. Note that the passive mode is also called a tag/card emulation mode. 
     When processing is started, the STA  100  first performs initial setup for the sleep state (S 401 ). Initial setup includes setting the NFC polling method and the temporal conditions for NFC departure in the wireless LAN functional unit  107  and the NFC unit  108 . Note that it is assumed that the wireless LAN functional unit  107  and the NFC unit  108  are provided with a control function equivalent to the control unit  101 . That is, it is assumed that the wireless LAN functional unit  107  and the NFC unit  108  are capable of operating without being instructed by the control unit  101  once they have been initialized by the control unit  101 . 
     After initial setup, the control unit  101  determines whether a partner apparatus is in proximity using the NFC unit  108  (S 402 ). When a partner apparatus is detected in proximity (YES at S 402 ), the STA  100  notifies information relating to its “NFC beacon function” and “NFC departure detection function” to the partner apparatus (AP  120 ) (S 403 ). For example, the STA  100  notifies that it has these functions, executable conditions (parameters), and the like to the AP  120 . At the same time, the STA  100  requests that the partner apparatus execute the NFC beacon operation. 
     Here, the “NFC beacon function” is a function for receiving notification that wireless LAN data exists from the partner apparatus via the NFC unit  108 , when the NFC unit  108  is operating in the passive mode, and conveying this notification to the wireless LAN functional unit  107  or the control unit  101 . Note that methods of notifying that data exists by NFC include the following two methods, for example. The first method involves indicating the existence of wireless LAN data by accessing a certain specific tag type or card mode. The second method involves indicating the existence of data by writing a specific value in a specific area during card mode operation. The AP, which has the NFC beacon function, notifies at least the Traffic Indication Map (TIM), out of the information included in a normal wireless LAN beacon, to the partner apparatus (STA) by NFC communication. The TIM is an information element notifying that there is data to be transmitted to a terminal under a power save mode. Also, the “NFC departure detection function” is a function for returning the control unit  101  to the awake state when access by NFC does not occur for a given period of time, in the case where the NFC unit  108  is operating in the passive mode and the control unit  101  is operating in the sleep state. 
     The STA  100  determines whether the AP  120  accepted the NFC beacon operation request, after notifying information relating to the NFC beacon function and the NFC departure detection function to the AP  120  (S 404 ). For example, the STA  100  determines whether the NFC beacon operation request was accepted by notification from the AP  120 . 
     In the case where the AP  120  does not accept the NFC beacon operation request (NO at S 404 ), the STA  100  deal with wireless LAN beacon operation (S 411 ), and ends the processing. In this case, the STA  100  does not cause the wireless LAN function to enter the sleep state, due to being unable to determine whether the STA  100  exists within the communicable range of the NFC unit  108  of the AP  120 . The STA  100  is thereby able to cause the wireless LAN functional unit  107  to enter the sleep state on condition of being communicable with the AP  120  by NFC, and is able to ensure that control of the wireless LAN functional unit  107  can be executed by NFC. That is, situations where communication using NFC cannot be performed can be prevented from arising, while maintaining the premise of performing state control of the wireless LAN functional unit  107  by NFC. 
     On the other hand, in the case where the AP  120  accepts the NFC beacon operation request (YES at S 404 ), an NFC connection handover (HO) procedure is executed (S 405 ). NFC connection handover is a procedure defined by the NFC Forum, and involves two communication apparatuses that have established NFC communication shifting from communication using NFC to communication using another wireless communication function such as wireless LAN. Hereinafter, this processing and procedure will be simply referred to as handover or HO. 
     Thereafter, the STA  100  executes wireless LAN connection setup with the AP  120  (S 406 ). Note that this procedure may be omitted in the case where wireless LAN connection has already been established. After completion of connection setup, the STA  100 , in the state where a wireless LAN connection is established with the AP  120 , notifies the AP  120  that the wireless LAN communication function will be entering the sleep state (S 407 ). Note that, at this time, the STA  100  holds the information relating to the wireless LAN functional unit  107  that is used in connecting to the AP  120  in the storage unit  102 . In this way, the STA  100  is able to perform communication by wireless LAN immediately after activation from the sleep state, by performing connection setup with the AP  120  before causing the wireless LAN functional unit  107  to enter the sleep state. Note that notification of entering the sleep state may be performed using either wireless LAN or NFC. 
     Next, the control unit  101  of the STA  100  sets the NFC unit  108  so as to be able to deal with an NFC beacon (S 408 ). The control unit  101  of the STA  100  then controls the wireless LAN functional unit  107  so as to enter the sleep state (S 409 ). The control unit  101  then enters the sleep state (S 410 ). 
     2. Routine Processing in Sleep State 
     This processing is executed by the NFC unit  108 , the timer  111  and the power storage unit  112 , after the control unit  101  has entered the sleep state. This processing will be described with reference to  FIG. 5 . In this processing, the timer  111  operates such that the timer is updated periodically (S 412 ). Also, the timer  111  determines whether the timer value has reached a predetermined value set in order to timeout (S 413 ), and, when the value of the timer  111  exceeds the predetermined value (YES at S 413 ), interrupts the control unit  101 . Thereafter, the processing shifts to the fourth processing which will be discussed later. Here, the period of the timer and the timeout value may be set at the stage of initial setup (S 401 ) before causing the wireless LAN to enter the sleep state. Note that the timeout value of the timer  111  is set to a value greater than the time interval for transmitting a confirmation signal (NFC polling) for confirming whether the STA  100  exists in the communicable range of the NFC unit  108  of the AP  120 . This is because a timeout will occur even when the STA  100  exists in the communicable range of the NFC unit  108  of the AP  120  when the timeout value is set to a value less than the time interval at which NFC polling is transmitted. Thus, the STA  100  may, for example, receive information indicating the transmission time interval of NFC polling from the AP  120 , and set the timeout value based on the received time interval information. 
     In the case where the value of the timer  111  is less than or equal to a predetermined value (NO at S 413 ), the NFC unit  108  next determines whether NFC polling is being received (S 414 ). The NFC unit  108 , in the case where NFC polling is being received (YES at S 414 ), returns a response to the NFC polling (S 415 ). Here, the response may be a logical information frame, or may be a simple ack signal in an electromagnetic field. Furthermore, the NFC unit  108  resets the counter of the timer  111  (S 416 ). Furthermore, if possible, the NFC unit  108  sends power received by NFC polling to the power storage unit  112  and charges the power storage unit  112 . Note that the power with which the power storage unit  112  is charged is, for example, power of the electric field produced by NFC polling that is the left over after driving the NFC unit  108 . The timer  111  can be operated continuously as a result of this power. Thereafter, the NFC unit  108  checks whether an NFC beacon has been received (S 417 ), and if not received (NO at S 417 ), returns the processing to S 411 . On the other hand, if the NFC unit  108  is receiving an NFC beacon (YES at S 417 ), the processing shifts to the third processing which will be discussed later. 
     3. Processing when there is Reception Data 
     This processing involves activating the wireless LAN from the sleep state when there is data addressed to the STA  100  and receiving the data from the AP  120 , and then causing the wireless LAN to enter the sleep state again after transmitting data if necessary. This processing will be described with reference to  FIG. 6 . 
     This processing is started in S 417 , upon receiving the NFC beacon (YES at S 417 ). The NFC unit  108  issues a trigger for activating the wireless LAN functional unit  107 , when the NFC beacon is received (S 418 ). As a result, the wireless LAN functional unit  107  then enters the awake state from the sleep state (S 419 ). The wireless LAN functional unit  107 , upon entering the awake state, transmits a PS-Poll frame to the AP  120  (S 420 ). This transmission processing is similar to processing that is executed, in general wireless LAN communication, in the case where the TIM included in the beacon indicates that data exists. That is, the STA  100  notifies the AP  120  that the wireless LAN functional unit  107  of the STA  100  has been activated from the sleep state, by the PS-Poll frame. The STA  100  is thereby able to notify the AP  120  that communication by wireless LAN is possible and that data reception preparation is completed. 
     After transmission of the PS-Poll frame, the wireless LAN functional unit  107  waits for data from the AP  120  (S 421 ), and receives all data that should be received (S 422 ). After all data that should be received has been received, the wireless LAN functional unit  107  sends a receive interrupt to the control unit  101  (S 423 ). In response to this interrupt, the control unit  101  processes the received data (S 424 ). The control unit  101  then determines whether there is any data to be transmitted as a result of this processing (S 425 ) and, if data to be transmitted exists (YES at S 425 ), transmits the data using the wireless LAN functional unit  107  (S 426 ). On the other hand, in the case where data to be transmitted does not exist (NO at S 425 ), the control unit  101  notifies the AP that the wireless LAN will enter the sleep state (S 427 ). Thereafter, the STA  100  returns the processing to the first processing (S 409  of  FIG. 4 ). 
     4. NFC Departure Detection and Related Processing 
     This processing involves causing the wireless LAN to enter the awake state from the sleep state, in the case where a timeout occurs during sleep without receiving NFC polling from a partner apparatus. This processing is executed in the case where a timeout occurs in S 413  of  FIG. 5 . This processing will be described with reference to  FIG. 7 . 
     When a timeout occurs without receiving polling, the operating state of the control unit  101  returns to the awake state from the sleep state (S 428 ). The control unit  101 , which is now in the awake state, recognizes that the STA  100  has departed from the communicable range of the NFC unit  108  of the AP  120 , and causes the wireless LAN functional unit  107  to enter the awake state from the sleep state (S 429 ). The STA  100  then transmits a notification indicating that the NFC beacon function is disabled to the AP  120  by wireless LAN communication (S 430 ). The AP  120  then resumes transmission of the beacon in response to having received the NFC beacon function disabled notification, and the STA  100  connects to the AP  120  by wireless LAN. The STA  100  is thereby able to cause the wireless LAN functional unit  107  to enter the sleep state on condition of being communicable with the AP  120  by NFC, and is able to ensure that control of the wireless LAN functional unit  107  is executable by NFC. 
     Note that methods of recognizing that the STA  100  has departed from the communicable range of the NFC unit  108  of the AP  120  include the following two methods, for example. The first method involves the control unit  101  reading out the time measured by the timer  111  and performing the determination, after returning to the awake state from the sleep state. That is, the control unit  101  recognizes that the STA  100  has departed from the communicable range of the NFC unit  108  of the AP  120  in the case where the measured time exceeds a predetermined value when the control unit  101  returns to the awake state from the sleep state. The second method involves the control unit  101  confirming the state of the wireless LAN functional unit  107  and the NFC unit  108 . In this case, the control unit  101  determines that a timeout has occurred when the wireless LAN functional unit  107  is in the sleep state at the time that the control unit  101  returns to the awake state. 
     Operation of AP  120   
     Next, the processing that is executed by the AP  120  will be described with reference to  FIGS. 8 to 10 . The processing that is executed by the AP  120  is broadly divided into four types of processing, similarly to the processing that is executed by the STA. The first processing is “processing until the terminal enters the sleep state”, the second processing is “routine processing when terminal in the sleep state”, the third processing is “processing when data addressed to the terminal is received”, and the fourth processing is “NFC departure detection and related processing”. This processing is executed by the control unit  101  of the AP  120 , unless specifically stated otherwise. 
     1. Processing Until Terminal Enters Sleep State 
     This processing will be described with reference to  FIG. 8 . The AP  120  first detects whether the partner apparatus (STA  100 ) exists in the communicable range of the NFC unit  108  (S 801 ). NFC communication is then executed with the STA  100 , which exist in the communicable range, and information about “NFC beacon function” capability is acquired (S 802 ). 
     If the STA  100  requests NFC beacon operation, the AP  120  then confirms whether a NFC beacon method that it has matches a method of the STA  100  (S 803 ). If matching methods do not exist, the AP  120  determines that NFC beacon operation is not possible (NO at S 803 ), notifies the NFC partner apparatus that a wireless LAN connection will be established using a wireless LAN beacon (S 804 ), and ends the processing. On the other hand, the AP  120 , in the case where it is determined that NFC beacon operation with the STA  100  is possible (YES at S 803 ), notifies the NFC beacon method (S 805 ). 
     The AP  120  then executes an NFC connection handover (HO) procedure (S 806 ). Thereafter, the AP  120  executes wireless LAN connection setup according to the contents of the HO procedure (S 807 ). Note that this procedure may be omitted in the case where wireless LAN connection setup has already been executed. The AP  120  then waits for notification of entering the sleep state from the STA  100 , after the end of connection setup (S 808 ). Note that, at this time, the AP  120  holds information relating to the connection of the wireless LAN functional unit  107  with the STA  100  in the storage unit  102 . In this way, the STA  100  is able to perform communication by wireless LAN immediately after activation from the sleep state, by performing connection setup with the AP  120  before causing the wireless LAN functional unit  107  to enter the sleep state. Note that waiting for the notification of entering the sleep state is executed by the control unit  101  controlling the wireless LAN functional unit  107  or the NFC unit  108 . 
     The AP  120 , upon receiving notification of entering the sleep state from the STA  100  (YES at S 808 ), then confirms that the STA  100  is the only connected wireless terminal, and stops transmission of the periodical wireless LAN beacon (S 809 ). Note that notification of entering the sleep state may be executed via the NFC unit  108 , or may be executed via the wireless LAN functional unit  107 . 
     2. Routine Processing by Terminal in Sleep State 
     This processing will be described using  FIG. 9 . The AP  120 , after stopping transmission of the wireless LAN beacon (S 809 ), shifts to the present processing and operates NFC polling processing periodically (S 810 ). This periodical operation is activated as a process or a task of software that operates in the control unit  101 , and operates independently of the flow of shifting the processing to S 811  which will be discussed later. 
     In polling processing, first a period timer is activated (S 901 ). The control unit  101  realizes this timer function with the data processing unit  103 , for example. Note that the difference from the timer operation of the STA  100  is that the control unit  101  of the AP  120  has not entered the sleep state. The AP  120  then transmits NFC polling (S 902 ) and waits for the response of the STA  100  to this polling (S 903 ). The AP  120 , in the case where there is a response from the STA  100  (YES at S 903 ), then resets the period timer (S 904 ), and executes the third processing which will be discussed later. On the other hand, for the period that there is no response from the STA  100  (NO at S 903 ), the AP  120  continually checks whether a timeout has occurred (S 905 ). If the period timer reaches the timeout value (YES at S 905 ), the AP  120  then advances the processing to S 818 , and executes the fourth processing which will be discussed later. 
     3. Processing when Data Addressed to Terminal Received 
     This processing will be described using  FIG. 10 . This processing is executed by the control unit  101  of the AP  120 , in the case where data to be transmitted to the STA  100  exists in the AP  120 . Note that, in the present embodiment, this processing is described as being executed in S 810  of  FIG. 9  in the case where an NFC polling response is received, but may be executed after S 809  of  FIG. 8  or during or after S 810  of  FIG. 9 , for example. 
     In this processing, the AP  120  waits for data addressed to the STA  100  (S 811 ). The AP  120 , upon data addressed to the STA  100  being received (YES at S 811 ), transmits an NFC beacon to the STA  100 , using the NFC unit  108  (S 812 ). Note that  FIG. 10  shows exemplary processing in the case of waiting until data to be transmitted is acquired, although a configuration may be adopted in which the AP  120  returns to the processing of  FIG. 9  and repeats periodical polling operation if data to be transmitted is not acquired. Also, a configuration may be adopted in which the processing of  FIG. 10  is only executed in the case where the data to be transmitted has arrived, and the processing may repeated from S 902 , rather than shifting to the processing of  FIG. 10 , in the case where a response to the polling is received in  FIG. 9 , for example. 
     The AP  120  waits for a PS-Poll from the STA  100  after beacon transmission (S 813 ). The AP  120 , upon receiving a PS-Poll (YES at S 813 ), then transmits the data addressed to the STA  100  with the wireless LAN functional unit  107  (S 814 ). This transmission processing is continually performed until all the data addressed to the STA  100  is transmitted. The AP  120  then waits for data from the STA  100  after all the data has been transmitted (S 815 ), and if data is received (YES at S 815 ), transfers this data in accordance with the address information (S 816 ), and advances the processing to S 817 . On the other hand, if data is not received from the STA  100  (NO at S 815 ), the processing advances to S 817 . The AP  120  then repeats the processing of S 815  and S 816  until the notification of entering the sleep state is received from the STA  100  (S 817 ). In S 817 , the AP  120 , in the case where notification of entering the sleep state is received from the STA  100  (YES at S 817 ), returns the processing to S 810  of  FIG. 9  and executes the NFC polling operation again, for example. Note that in this case, the AP  120  may return the processing to S 811  and wait for data addressed to the STA  100 . 
     4. NFC Departure Detection and Related Processing 
     This processing is performed when the control unit  101  detects a timeout in S 905  of  FIG. 9 . The AP  120 , upon detecting a timeout (YES at S 905 ), executes processing that is performed in the case where an NFC response is not received, as shown in  FIG. 9  (S 818 ). This processing involves, for example, outputting a warning message using the output unit  105 . Note that a configuration may be adopted in which the AP  120  resumes periodically sending out the wireless LAN beacon and connects to the STA  100  by wireless LAN, rather than outputting a warning message. 
     Operations of System 
     Next, the flow of processing between the STA  100  and the AP  120  will be described using the sequence diagrams of  FIGS. 11 to 13 .  FIGS. 11 and 12  are sequence diagrams regarding processing that is performed in the case where the STA  100  does not depart from the communicable range of the NFC unit  108  of the AP  120 .  FIG. 13  is a sequence diagram regarding processing for determining whether the STA  100  has departed from the communicable range of the NFC unit  108  of the AP  120 . 
     First, processing in the case where the STA  100  has not departed from the communicable range of the NFC unit  108  of the AP  120  will be described using  FIGS. 11 and 12 . When processing is started, the STA  100  recognizes a sleep state setup operation by the user, and performs sleep state setup (F 1001 ). The STA  100  and the AP  120  then detect the NFC proximity state (F 1002 ), and establish a connection using NFC. Thereafter, the STA  100  performs notification of “NFC beacon function” and “NFC departure detection function” capabilities (F 1003 ), and the AP  120  determines the method of the NFC beacon function and notifies the STA  100  (F 1004 ). After notifying the method of the NFC beacon function, the AP  120  and the STA  100  perform the NFC connection handover (HO) procedure (F 1005 ), and perform wireless LAN connection setup (F 1006 ). 
     The STA  100  then transmits notification of entering the sleep state to the AP  120  after completing the wireless LAN connection setup (F 1007 ). The AP  120 , upon receiving notification of entering the sleep state, then stops sending out the wireless LAN beacon (F 1008 ). On the other hand, the STA  100  enables the NFC beacon function after transmitting the notification of entering the sleep state (F 1009 ). Note that it is assumed that the NFC beacon function of the AP  120  is already enabled in F 1004 . Thereafter, the STA  100  causes the wireless LAN functional unit  107  to transition to the sleep state (F 1010 ), and furthermore causes the control unit  101  to enter the sleep state (F 1011 ). 
     In this state, in the STA  100 , the control unit  101  and the wireless LAN functional unit  107  will have stopped functioning, and only the NFC beacon function (and the timer  111 ) will be active. In this case, the NFC beacon function can be activated by an electric field or magnetic field that is produced by the AP  120 , and power for the timer  111  can similarly be obtained from the AP  120  by the NFC unit  108 . Accordingly, it becomes possible for the STA  100  to wait for data without consuming power. Also, it becomes possible for the AP  120  to suppress power consumption, since sending out of the wireless LAN beacon is stopped. Also, in the AP  120 , as long as there is no data to be transmitted to or received from the STA  100 , is able to stop (put to sleep) the wireless LAN function. Accordingly, it becomes possible for the AP  120  to greatly reducing power relating to wireless LAN. 
     Here, as shown in  FIG. 12 , it is assumed that after the STA  100  has caused the control unit  101  and the wireless LAN functional unit  107  to enter the sleep state, the AP  120  receives data addressed to the STA  100  (F 1012 ). In this case, the AP  120  transmits the NFC beacon to the STA  100  (F 1013 ). With this NFC beacon, the wireless LAN functional unit  107  of the STA  100 , as a result of being triggered (F 1014 ), enters the awake state (F 1015 ), and transmits the PS-Poll (F 1016 ). The AP  120 , upon receiving the PS-Poll, transmits data to the STA  100  (F 1017 ). When the wireless LAN functional unit  107  of the STA  100  detects the end of data reception (F 1018 ), the control unit  101  of the STA  100  enters the awake state (F 1019 ). Thereafter, if necessary, the STA  100  transmits data to the AP  120  (F 1020 ), and confirms that data transmission has ended (F 1021 ). Thereafter, the STA  100  transmits notification of the wireless LAN entering the sleep state to the AP  120  (F 1022 ). After notification, the wireless LAN functional unit  107  of the STA  100  enters the sleep state (F 1023 ), and then the control unit  101  of the STA  100  enters the sleep state (F 1024 ). 
     Next, processing for determining whether the STA  100  has departed from the communicable range of the NFC unit  108  of the AP  120  will be described with reference to  FIG. 12 . In this processing, first, the AP  120  transmits NFC polling to the STA  100  (F 1025 ), and the STA  100  transmits a polling response to the AP  120  (F 1026 ). In this case, since the STA  100  is considered to exist in the communicable range of the NFC unit  108  of the AP  120 , the timer  111  of the STA  100  is then reset (F 1027 ). 
     Here, it is assumed that the STA  100  departs from the communicable range of the NFC unit  108  of the AP  120  by having moved or the like, and that NFC communication is disconnected (F 1028 ). In this case, the NFC polling transmitted by the AP  120  will not be received by the STA  100 , and the AP  120  will not receive a response from the STA  100  (F 1029 ). In this way, the AP  120  confirms that no response has been received from the STA  100  as a result of the timer timing out (F 1030 ), and detects that the STA  100  has departed from the communicable range of the NFC unit  108  of the AP  120 . On the other hand, in the STA  100 , since NFC polling is not received, the timer  111  exceeds the predetermined value and a timeout occurs (F 1031 ). Then the control unit  101  of the STA  100 , as a result of being interrupted (F 1032 ), transitions to the awake state (F 1033 ). The wireless LAN functional unit  107  of the STA  100  also transitions to the awake state (F 1034 ). The STA  100  then transmits a notification indicating that the NFC beacon function is disabled to the AP  120  (F 1035 ), and thereafter the STA  100  and the AP  120  execute similar processing to when wireless LAN communication is executed in the case where NFC communication is not possible (F 1036 ). That is, the AP  120  resumes sending out of the wireless LAN beacon, and the STA  100  connects to the AP  120  by wireless LAN. 
     In this way, the availability of communication using NFC can be linked to the wireless LAN entering the sleep state, by placing the wireless LAN in the sleep state in the case where the STA  100  exists in the communicable range of the NFC unit  108  of the AP  120 . In this way, in the case where communication using NFC cannot be performed, a state where communication is possible by wireless LAN can be maintained, instead of placing the wireless LAN in the sleep state. Also, it becomes possible to suppress power consumption while securing a state where communication can be performed by wireless LAN, by placing the wireless LAN in the sleep state when communication can be performed using NFC. Furthermore, communication having high power efficiency becomes possible in the case where communication can be performed using NFC after the wireless LAN has entered the sleep state, by only canceling the sleep state in the case where there is data to be transmitted. 
     Note that, in the embodiments, reducing power consumption by stopping transmission of signals that are transmitted periodically, such as the wireless LAN beacon and the like, and transitioning to the sleep state when communication apparatuses are able to communicate using NFC was described. However, the embodiments are merely for illustrative purposes, and the present invention is not limited thereto. For example, a configuration may be adopted in which power consumption is reduced by stopping or restricting transmission of predetermined signals other than signals that are transmitted periodically such as the beacon or the like, when communication apparatuses are able to communicate using NFC. For example, a configuration may be adopted in which transmission of signals such as a wireless LAN probe request or probe response is stopped or restricted, when communication apparatuses are able to communicate using NFC. 
     According to the present invention, it becomes possible to reduce power usage in apparatuses that are capable of utilizing a plurality of communication methods. 
     Other Embodiments 
     Embodiments of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions recorded on a storage medium (e.g., non-transitory computer-readable storage medium) to perform the functions of one or more of the above-described embodiment(s) of the present invention, and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more of a central processing unit (CPU), micro processing unit (MPU), or other circuitry, and may include a network of separate computers or separate computer processors. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2013-133093 filed on Jun. 25, 2013, which is hereby incorporated by reference herein in its entirety.