Abstract:
A communication apparatus includes: a transmitter configured to transmit to an external apparatus a search signal for requesting the external apparatus to transmit an address that is uniquely assigned to the external apparatus; a receiver configured to receive a response signal being transmitted from the external apparatus in response to the search signal, the response signal containing positional information and the address of the external apparatus; and an extractor configured to extract the positional information from the response signal received by the receiver.

Description:
CROSS-REFERENCE TO THE RELATED APPLICATION(S) 
       [0001]    The present application is based upon and claims priority from prior Japanese Patent Application No. 2009-280932, filed on Dec. 10, 2009, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    This embodiment relates to a communication apparatus and a positional information communicating method. 
         [0004]    2. Description of the Related Art 
         [0005]    Techniques of acquiring current positional information using a GPS position determining system or the like are known. To utilize such a technique, it is necessary to prepare a module having a position determining function. However, an apparatus incorporating such a module may become heavier, larger in size, and more expensive. A technique is therefore desired that enables acquisition of current positional information even in an apparatus that is not equipped with a module having a position determining function. 
         [0006]    In these circumstances, techniques are available which detect a current position by acquiring position data from a communication apparatus having a GPS position determining function or the like. In a conventional system, a portable terminal receives position data from a communication apparatus having a GPS position detecting section or the like by a narrow-band communication and sends the received position data to a center. 
         [0007]    However, in acquiring positional information by communicating with an apparatus having a position determining function, a communication destination may be set in advance, before establishment of communication connection. Furthermore, communication connection processing takes long time. As a result, positional information may not be acquired easily. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    A general configuration that implements the various features of the present invention will be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. 
           [0009]      FIG. 1  shows an example usage of a communication system to which a first embodiment of the present invention is applied. 
           [0010]      FIG. 2  shows the configuration of another communication system to which the first embodiment of the invention is applied. 
           [0011]      FIG. 3  shows pieces of information contained in an EIR which is transmitted in the first embodiment of the invention. 
           [0012]      FIG. 4  shows an information table which is generated in the first embodiment of the invention. 
           [0013]      FIG. 5  shows a position selection screen which is displayed in the first embodiment of the invention. 
           [0014]      FIG. 6  shows an operation sequence of a communication system which performs a conventional Bluetooth communication. 
           [0015]      FIG. 7  shows an operation sequence of a communication system to which the first embodiment of the invention is applied. 
           [0016]      FIG. 8  shows the procedure of an operation that a communication apparatus sends an EIR in the first embodiment of the invention. 
           [0017]      FIG. 9  shows the procedure of an operation that a communication apparatus determines its position in the first embodiment of the invention. 
           [0018]      FIG. 10  shows a positional information display screen which is displayed by the communication apparatus of  FIG. 9  in the first embodiment of the invention. 
           [0019]      FIG. 11  shows pieces of information contained in an EIR which is transmitted in a second embodiment of the invention. 
           [0020]      FIG. 12  shows the procedure of an operation that a communication apparatus determines its position in the second embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The scope of the claimed invention should not be limited to the examples illustrated in the drawings and those described in below. 
       First Embodiment 
       [0022]      FIG. 1  schematically shows an example usage of a communication system to which a first embodiment is applied. This communication system is provided with a cell phone  10 , a car navigation apparatus  20 , a cell phone  30  and a digital camera  40 . 
         [0023]    Equipped with a GPS module  11  and a Bluetooth (registered trademark) module  12 , the cell phone  10  is capable of acquiring current positional information when the GPS module  11  receives a signal from a GPS satellite  50 . Equipped with a GPS module  21  and a Bluetooth module  22 , the car navigation apparatus  20  is capable of acquiring current positional information using the GPS module  21  like the cell phone  10  can. In the cell phone  30  which is quipped with a base station position determining module  31  and a Bluetooth module  32 , the base station position determining module  31  is capable of acquiring positional information of a closest cell phone base station  60  from the cell phone base station  60 . 
         [0024]    The digital camera  40  is equipped with a Bluetooth module  41 , however, is not provided with a dedicated module for determining its own position. 
         [0025]    This embodiment allows an apparatus having no dedicated position determining module such as the digital camera  40  to acquire positional information from, for example, an apparatus having a position determining module such as the cell phone  10 , the car navigation apparatus  20 , or the cell phone  30 . 
         [0026]    In this communication system, the digital camera  40  sends, to unspecified apparatus inquiry signal (signal “Inquiry”), which is a search signal used in Bluetooth communication. Inquiry signal is to request an apparatus that has received the inquiry signal to send back a response signal containing its own Bluetooth address. The Bluetooth address is a unique address that is assigned to each Bluetooth module. 
         [0027]    When receiving inquiry signal from the digital camera  40 , each of the cell phone  10 , the car navigation apparatus  20 , and the cell phone  30  sends, to the digital camera  40 , an EIR (extended inquiry response) which is a response signal containing positional information. The digital camera  10  receives the EIRs and extracts pieces of positional information contained in the respective EIRs. In this manner, the digital camera  10  can easily acquire pieces of positional information without the need for establishing communication connections to unspecified apparatus. The EIR will be described later with reference to  FIG. 3 . 
         [0028]    Bluetooth modules are incorporated in various apparatus. For example, there are cell phones and car navigation apparatus that are equipped with a Bluetooth module to send audio data to a hands-free headset or the like. Furthermore, there are such electronic apparatus as digital cameras that are equipped with a Bluetooth module to enable data exchange with a PC or the like. 
         [0029]    That is, the embodiment not only makes it possible to easily acquire pieces of positional information from unspecified apparatus by receiving response signals containing the respective pieces of positional information but also enables using existing communication modules such as Bluetooth modules. 
         [0030]    Next, another communication system to which the embodiment is applied will be described with reference to  FIG. 2 . This communication system is provided with a communication apparatus  100  and a communication apparatus  200 , each of which can perform a wireless communication according to the Bluetooth standard. The communication apparatus  100  is equipped with a communication module  101 , a signal level detector  102 , a communication controller  103 , an information extractor  104 , a position determining module  105 , an user interface  106 , a memory  107 , a video processor  108 , and a display device  109 . Examples of the communication apparatus  100  are a cell phone, a digital camera, and a PC, each of which is not provided with a dedicated position determining module. 
         [0031]    The communication module  101  sends and receives a signal to and from an external communication apparatus. When receiving an inquiry signal transmission command from the communication controller  103 , the communication module  101  sends, to unspecified communication apparatus, inquiry signal for requesting sending-back of a Bluetooth address. When receiving an EIR containing positional information from the communication apparatus  200  or the like, the communication module  101  supplies the received EIR to the communication controller  103 . After receiving the EIR, the communication module  101  establishes a communication connection to the external apparatus having the Bluetooth address contained in the received EIR by sending a connection request signal to the external apparatus (i.e., to the received Bluetooth address). 
         [0032]    When the communication module  101  receives an EIR, the signal level detector  102  detects reception signal level of the EIR and supplies information indicating the detected reception signal level to the information extractor  104 . 
         [0033]    The communication controller  103  generates inquiry signal and supplies it to the communication module  101 , and supplies an inquiry signal transmission command to the communication module  101 . The communication controller  103  may perform generation of inquiry signal and output of an inquiry signal transmission command either automatically at regular time intervals or in response to a certain manipulation of the user. 
         [0034]    The communication controller  103  supplies the information extractor  104  with an EIR that is received from the communication module  101 . The communication controller  103  determines whether or not a prescribed time T (sec) has elapsed from the transmission of inquiry signal by the communication module  101 . The prescribed time T is a preset timeout period of EIR reception processing. When the prescribed time T has elapsed from the transmission of inquiry signal, the communication controller  103  supplies the information extractor  104  with a notice to that effect and causes timeout of the EIR reception processing. 
         [0035]    The information extractor  104  extracts Bluetooth address information, positional information, etc. that are contained in each EIR that is input from the communication controller  103 . The information extractor  104  generates an information table in which the extracted pieces of positional information etc. are correlated with the respective reception signal level values received from the signal level detector  102 . The information extractor  104  updates the information time every time it receives an EIR. When receiving a notice to the effect that the prescribed time T has elapsed, the information extractor  104  supplies the information table to the position determining module  105 . The information table will be described later with reference to  FIG. 4 . 
         [0036]    The position determining module  105  performs position determination processing for determining the position of the communication apparatus  100  based on the information table received from the information extractor  104 . In the position determination processing, if an EIR was received from only one external apparatus, the position determining module  105  employs, as a position of the communication apparatus  100 , the position indicated by the positional information that was extracted from the received EIR. If EIRs were received from plural external apparatus within the prescribed time T from the transmission of inquiry signal, the position determining module  105  determines the position of the communication apparatus  100  based on the plural pieces of positional information that were extracted from the received EIRs. The position determining module  105  supplies positional information indicating the determined position of the communication apparatus  100  to the memory  107  and the video processor  108 . 
         [0037]    Among methods of position determination which is performed by the position determining module  105  are a method of calculating an average of plural positions and employing it as a position of the communication apparatus  100  and a method of selecting positional information based on EIR transmission signal level values and EIR reception signal level values. The details of the position determination processing as well as the details of the information table will be described later with reference to  FIG. 4 . 
         [0038]    The user interface  106  receives an operation command input by the user. An example user operation command is a user operation command that is made through a position selection screen which is displayed in the position determination processing, which will be described later with reference to  FIG. 4 . 
         [0039]    The memory  107  serves as a storage medium for storing positional information that is supplied from the position determining module  105 . Example storage media are a hard disk drive, a memory, and an optical disc. The memory  107  may output stored positional information to the video processor  108 . The memory  107  may be stored with map images etc. and output positional information and a map image to the video processor  108 . Where the communication apparatus  100  is a digital camera, the memory  107  may store positional information as part of Exif data of an image taken by itself. 
         [0040]    The video processor  108  generates a positional information display screen for display of the position of the communication apparatus  100  based on the positional information received from the position determining module  105  or the memory  107 . The positional information display screen may be a screen in which the positional information is displayed in the form of a latitude and a longitude, an address, or the like or a screen in which a map image including the position of the communication apparatus  100  and its neighborhood is displayed based on the positional information and a map image that is input from the memory  107 . 
         [0041]    When the communication apparatus  100  has received EIRs from plural external apparatus, the video processor  108  may display a position selection screen for allowing the user to select, as a position of the communication apparatus  100 , one of the positions indicated by the pieces of positional information of the plural external apparatus. The pieces of positional information etc. of the plural external apparatus contained in the received EIRs are displayed in the position selection screen to allow the user to select one of the pieces of positional information. The details of the position selection screen will be described later with reference to  FIG. 5 . 
         [0042]    The video processor  108  supplies a signal of the generated positional information display screen or position selection screen to the display device  109 , and the display device  109  displays the received screen. 
         [0043]    Next, the communication apparatus  200  will be described. The communication apparatus  200  is equipped with a positional information acquiring section  201 , a communication controller  202 , a communication module  203 , etc. 
         [0044]    The positional information acquiring section  201  acquires positional information using the GPS, a position determining system using cell phone base stations, or a like system. And the positional information acquiring section  201  supplies the acquired positional information to the communication controller  202 . The positional information acquiring section  201  acquires positional information every 10 seconds, for example, and supplies the acquired positional information to the communication controller  202 . 
         [0045]    The positional information acquiring section  201  need not always be such as to use a position determining system. For example, where the communication apparatus  200  is fixed at a particular location, the positional information acquiring section  201  may such as to acquire positional information that, for example, is input by the user. 
         [0046]    The communication controller  202  controls reception of inquiry signal and transmission of an EIR. When receiving inquiry signal from the communication module  203 , the communication controller  202  generates an EIR and supplies it to the communication module  203 . The communication controller  202  generates an EIR which contains a Bluetooth address of the communication apparatus  200 , positional information which is received from the positional information acquiring section  201 , and transmission signal level at which the EIR is sent. The EIR will be described later with reference to  FIG. 3 . 
         [0047]    The communication controller  202  may be provided with a storage area for buffering positional information that is input from the positional information acquiring section  201 . In this case, the buffered positional information can be updated every time new positional information is input from the positional information acquiring section  201 . The communication controller  202  generates an EIR which contains the buffered positional information. 
         [0048]    The communication module  203  receives inquiry signal and transmits an EIR. When receiving inquiry signal, the communication module  203  supplies it to the communication controller  202 . When receiving an EIR from the communication controller  202 , the communication module  203  sends it to the communication apparatus  100 . After sending the EIR to the communication apparatus  100 , the communication module  203  establishes a communication connection to the communication apparatus  100  by performing authentication processing on a connection request signal that is transmitted from the communication apparatus  100  and contains the Bluetooth address of the communication apparatus  200  and other processing. 
         [0049]    Next, the EIR which is sent from the communication apparatus  200  will be described with reference to  FIG. 3 , which shows an EIR data structure. The EIR is information which is sent in responding to inquiry signal which is a search signal for searching for Bluetooth-compatible apparatus. The EIR can contain, in addition to an apparatus Bluetooth address A 1  etc. which are contained in an ordinary inquiry signal response, various kinds of information such as transmission signal level A 2 , an apparatus vender name (not shown), and an apparatus product name (not shown). The transmission signal level is signal level at which the communication apparatus  200  sends the EIR. In the embodiment, apparatus positional information A 3  is contained in the EIR as additional data. Example forms of the positional information A 3  are a latitude/longitude combination and an address. The positional information A 3  may contain such information as an altitude in addition to a latitude/longitude combination, an address, or the like. 
         [0050]      FIG. 4  shows an example of the information table which the information extractor  104  updates when it receives EIR data from the communication controller  103 . In the information table, the positional information, the transmission signal level, etc. that are contained in each EIR supplied to the information extractor  104  and reception signal level detected by the signal level detector  202  are correlated with the designation of the EIR. The information table may be such that the vender name, the product name, the apparatus type, and other information contained in each EIR supplied to the information extractor  104  are also correlated with the designation of the EIR. If the communication apparatus  100  has received an EIR which contains positional information indicating a latitude N 40.35.48 and a longitude E 135.30.23 and transmission signal level +10 dBm and the signal level detector  102  has detected EIR reception signal level −40 dBm, the information extractor  104  updates the information table so that information B 1  is added (see  FIG. 4 ). The information extractor  104  updates the information table every time it receives a new EIR. 
         [0051]    When EIRs have been received from plural external apparatus, the position determining module  105  performs position determination processing for determining the position of the communication apparatus  100  based on the information table. One method of the position determination processing is to use reception signal level values contained in the information table. 
         [0052]    In this method, the position determining module  105  selects, as positional information of the communication apparatus  100 , the positional information that is contained in an EIR that was received at highest reception signal level among the plural positional information. For example, in the example of  FIG. 4 , since an EIR 1  has highest reception signal level, the position determining module  105  selects, as positional information of the communication apparatus  100 , the positional information that is contained in the EIR 1 . Where EIR transmission signal level values are approximately the same, the EIR reception signal level is higher when the external apparatus is closer to the communication apparatus  100 . Therefore, the positional information of an external apparatus that is closer to the communication apparatus  100  can be selected by selecting the positional information that is contained in an EIR having higher reception signal level. 
         [0053]    Another method is possible in which attenuation amounts of EIR signal level are calculated based on reception signal level values and transmission signal level values that are contained in the information table and the positional information that is extracted from an EIR that is lowest in the degree of signal level attenuation is selected. An attenuation amount of signal level is calculated according to the following equation: 
         [0000]      (Attenuation amount)=(Transmission signal level)−(Reception Signal Level)
 
         [0054]    For example, for the EIR 1 , EIR 2 , and EIR 3  shown in  FIG. 4 , attenuation amounts are calculated as follows according to this equation: 
         [0000]      +10−(−40)=50 dBm  EIR1
 
         [0000]      +4−(−60)=64 dBm  EIR2
 
         [0000]      +15−(−50)=65 dBm  EIR3
 
         [0055]    Since the attenuation amount of the EIR 1  is smallest, the position determining module  105  employs, as a position of the communication apparatus  100 , the positional information that was extracted from the EIR 1 . 
         [0056]    In this manner, even in the case where EIRs containing different transmission signal level values are received from plural external apparatus, the position indicated by the positional information of an external apparatus that is closest to the communication apparatus  100  can be selected as a position of the communication apparatus  100  based on EIR signal level attenuation amounts. 
         [0057]    Furthermore, in determining the position of the communication apparatus  100 , the position determining module  105  may calculate a position based on plural pieces of positional information. For example, the position determining module  105  calculates an average of plural positions and employs it as a position of the communication apparatus  100 . 
         [0058]    Still further, when EIRs have been received from plural external apparatus, the position determining module  105  may determine the position of the communication apparatus  100  based on a operation command of the user. More specifically, the position determining module  105  supplies the video processor  108  with an information table that has been generated based on plural EIRs. The video processor  108  generates, based on the received information table, a position selection screen that allows the user to select one of plural pieces of positional information, and the display device  109  displays the position selection screen. 
         [0059]      FIG. 5  shows an example position selection screen which is generated by the video processor  108 . This position selection screen is generated based on the information table received from the position determining module  105  so as to contain sets of positional information and transmission signal level, reception signal level, and other information that correspond to the positional information. The position selection screen may also contain an apparatus vender name, an apparatus product name, and other information in such a manner that they are correlated with each piece of positional information. The position selection screen also contains selection buttons D 1 , D 2 , and D 3  that allow the user to select the position indicated by one of the plural pieces of positional information as a position of the communication apparatus  100 . When the user interface  106  receives a manipulation on the selection button D 1 , D 2 , or D 3 , the position determining module  105  employs, as a position of the communication apparatus  100 , the position indicated by the positional information that has been selected by the user operation command. 
         [0060]    Next, an operation sequence of a communication system which performs an ordinary Bluetooth communication will be described with reference to  FIG. 6 . This communication system is provided with communication apparatus  400 ,  500 , and  600  etc. Each of the communication apparatus  400 ,  500 , and  600  is equipped with a module which performs a Bluetooth communication. 
         [0061]    First, at step S 401 , the communication apparatus  400  sends inquiry signal to external apparatus to search for external apparatus capable of wireless communication according to the Bluetooth standard and to acquire their Bluetooth addresses. The communication apparatus  400  sends inquiry signal to a large number of unspecified external apparatus rather than particular external apparatus. At steps S 402  and S 403 , when receiving the inquiry signal, the communication apparatus  500  and  600  send back inquiry signal responses which are response signals to the inquiry signal, respectively. The inquiry signal responses which are sent from the communication apparatus  500  and  600  contain their respective Bluetooth addresses. 
         [0062]    At step S 404 , the communication apparatus causes timeout of inquiry signal response reception processing if a time T (sec) has elapsed from the transmission of the inquiry signal at step S 401 . The time T is a preset timeout period of the inquiry signal response reception processing. The communication apparatus  400  does not process an inquiry signal response that is received after a timeout. 
         [0063]    At step S 405 , the communication apparatus  400  employs, as a connection destination, one of the Bluetooth addresses contained in received inquiry signal responses and sends a connection request that contains the Bluetooth address as the connection destination. If the Bluetooth address that has been employed as the connection destination is the Bluetooth address of the communication apparatus  500 , for example, at step S 406  the communication apparatus  400  and  500  start connection establishment processing. In the connection establishment processing, the communication apparatus  400  and  500  perform verification of an authentication key and other processing. If the connection establishment processing is completed, at step S 407  the communication apparatus  400  and  500  exchange image data, audio data, or the like by performing a communication. 
         [0064]    Next, an operation sequence of a communication system according to the embodiment will be described with reference to  FIG. 7 . Whereas in the operation of  FIG. 6  data is transferred after establishment of a connection, in the operation of  FIG. 7  positional information can be incorporated in an EIR. 
         [0065]    This communication system is provided with communication apparatus  100 ,  200 , and  300 . It is assumed that the communication apparatus  100  and  200  have the same configurations as those described above with reference to  FIG. 2  and the communication apparatus  300  has the same configuration as the communication apparatus  200 . 
         [0066]    At step S 501  and S 502 , the communication apparatus  200  and  300  acquire positional information. At step S 503 , the communication apparatus  100  sends inquiry signal. When receiving the inquiry signal, at step S 504  and S 505  the communication apparatus  200  and  300  send, to the communication apparatus  100 , as response signals, EIRs containing their respective pieces of positional information and pieces of other information. At step S 506 , the communication apparatus  100  causes timeout of EIR reception processing when the time T (sec) has elapsed from the transmission of the inquiry signal. 
         [0067]    Whereas the transmission of inquiry signal, the transmission of an EIR in response to the inquiry signal, etc. correspond to the transmission of inquiry signal, the transmission of an inquiry signal response, etc. that are performed in the communication system of  FIG. 6  which performs an ordinary Bluetooth communication, the communication system of  FIG. 7  according to the embodiment is different from the communication system of  FIG. 6  in that each response signal (EIR) to the inquiry signal contains positional information. 
         [0068]    When a timeout has occurred in the EIR reception processing, at step S 507  the communication apparatus  100  performs position determination processing. In the position determination processing, as described above, the communication apparatus  100  determines its position based on the pieces of positional information extracted from the received EIRs. 
         [0069]    Then, steps S 508 - 510  can be performed. That is, at step S 508 , the communication apparatus  100  sends, to the communication apparatus  200 , for example, having the Bluetooth address that was contained in one of the received EIRs, a connection request containing that Bluetooth address. At step S 509 , the communication apparatus  100  and  200  perform connection establishment processing. After establishment of a connection, at step S 510  the communication apparatus  100  and  200  performs a communication. In the embodiment, pieces of positional information can be acquired without the need for executing step S 508 - 510 . 
         [0070]    Next, an operation that the communication apparatus  200  sends an EIR containing positional information will be described with reference to  FIG. 8 . 
         [0071]    First, at step S 601 , the positional information acquiring section  201  acquires positional information. This can be done by using the GPS, a position determining system using cell phone base stations, or a like system. Where the communication apparatus  200  is fixed at a particular location, the positional information acquiring section  201  may acquire positional information that is manipulation-input by the user. The positional information acquiring section  201  supplies the acquired positional information to the communication controller  202 . 
         [0072]    When the communication module  203  receives inquiry signal at step S 602 , at step S 603  the communication controller  202  generates an EIR containing the positional information and the communication module  203  sends out the EIR. 
         [0073]    With the above operation, the communication apparatus may send positional information easily without the need for establishing a communication connection to the communication apparatus  100 . Since it is not necessary to establish a communication connection, the time that is taken by the positional information transmission processing can be shortened. Since the communication apparatus  200  sends an EIR containing positional information in response to inquiry signal that is transmitted from the communication apparatus  100 , the communication apparatus may send positional information when the communication apparatus requires the positional information. 
         [0074]    Next, an operation that the communication apparatus  100  determines its position will be described with reference to  FIG. 9 . 
         [0075]    First, at step S 701 , the communication module  101  sends inquiry signal to unspecified external apparatus. At step S 702 , when the communication module  101  receives an EIR as a response to the inquiry signal at step S 702 , at step S 703  the signal level detector  102  detects reception signal level of the EIR and supplies information indicating the reception signal level to the information extractor  104 . At step S 104 , the information extractor  104  extracts the positional information etc. that are contained in the EIR. At step S 705 , the information extractor  104  generates (or updates) an information table using the extracted positional information, the information indicating the reception signal level supplied from the signal level detector  102 , and other information. 
         [0076]    At step S 706 , the communication controller  103  determines whether or not the time T (sec) has elapsed from the transmission of the inquiry signal. If the time T has not elapsed yet (S 706 : no), the communication apparatus  100  executes steps S 702 -S 706  again. In this manner, reception signal level is detected, positional information is extracted, and the information table is updated every time an EIR is received. 
         [0077]    If the time T has elapsed from the transmission of the inquiry signal (S 706 : yes), at step S 707  the communication controller  103  determines whether or not an EIR(s) has been received. If an EIR(s) has not been received (S 707 : no), this operation is finished. If an EIR(s) has been received (S 707 : yes), the communication controller  103  supplies the information extractor  104  with a notice to the effect that the time T has elapsed. When receiving this notice, at step S 708  the information extractor  104  supplies the generated information table to the position determining module  105 . And the position determining module  105  performs the above-described position determination processing based on the received information table and supplies positional information indicating a determined position of the communication apparatus  100  to the memory  107 . 
         [0078]    At step S 709 , the memory  107  (memory, hard disk drive, or the like) stores the positional information received from the position determining module  105  (permanent or temporary storage) and supplies the positional information to the video processor  108 . At step S 710 , the video processor  108  generates a positional information display screen for display of the positional information indicating the determined position of the communication apparatus  100  and supplies a signal of this screen to the display device  109 . 
         [0079]      FIG. 10  shows an example positional information display screen which is displayed by the display device  109 . In the screen of  FIG. 10 , positional information is displayed in the form of a latitude/longitude combination and an address. A map image including the position of the communication apparatus  100  and its neighborhood may be displayed in the positional information display screen. Where the communication apparatus  100  is a digital camera, an image taken by itself may be displayed so as to be correlated with the positional information or the positional information may be stored as part of Exif data of an image taken by itself. 
         [0080]    With the above operation, the communication apparatus  100  can easily acquire pieces of positional information from unspecified external apparatus without the need for determining communication destinations, establishing communication connections, and performing other processing. Since the communication apparatus  100  is capable of acquiring pieces of positional information without establishing communication connections or performing other processing, the time taken to acquire pieces of positional information can be shortened. The communication apparatus  100  is capable of acquiring pieces of positional information with proper timing by sending inquiry signal when it needs them. Furthermore, when receiving EIRs containing respective pieces of positional information from plural external apparatus, the communication apparatus  100  can select positional information indicating a position that is determined closest to the communication apparatus  100  based on sets of reception signal level, transmission signal level, and other information. 
       Second Embodiment 
       [0081]    Next, a second embodiment of the invention will be described with reference to  FIGS. 11 and 12 . In this embodiment, the communication apparatus may send an EIR which contains, in addition to transmission signal level and positional information, information indicating whether or not the positional information is of an apparatus that is fixed at a particular location. When receiving plural EIRs, the communication apparatus  100  preferentially selects (pieces of) positional information of a fixed apparatus among the pieces of positional information contained in the received EIRs. The term “apparatus fixed at a particular location” means an apparatus that is installed at such a location as a sightseeing spot or a location (e.g., the inside of a building or underground) where a position determination module such as the GPS cannot be used and that can send an EIR in response to inquiry signal, or a like apparatus. Since such an apparatus is fixed and does not vary in position, it need not be equipped with a position determination module. Such an apparatus may acquire positional information by, for example, causing the user to manipulation-input positional information. In this manner, the communication apparatus  100  can preferentially select correct positional information at a location where a position determination module cannot be used or a famous location. 
         [0082]    The configurations of the apparatus will not be described in detail because they are substantially the same as in the first embodiment. 
         [0083]      FIG. 11  shows an example structure of data that are contained in an EIR which is sent by the communication apparatus  200  in the embodiment. The EIR contains a Bluetooth address C 1 , transmission signal level C 2 , positional information C 3 , and a flag C 4  indicating whether the position is fixed or not. 
         [0084]    Next, an operation of the communication apparatus  100  according to the embodiment will be described with reference to  FIG. 12 . Steps S 801 -S 803 , steps S 806  and S 807 , and steps S 811  and S 812  in  FIG. 12  are the same as steps S 701 -S 703 , steps S 706  and S 707 , and steps S 709  and S 710  in  FIG. 9 , respectively. Steps that are different than in the operation of  FIG. 9  will mainly be described below. 
         [0085]    After the communication apparatus  100  sent inquiry signal and detected reception signal level of a received EIR at steps S 801 -S 803 , at step S 804  the information extractor  104  of the communication module  100  extracts, from the EIR, the Bluetooth address, positional information, transmission signal level, information indicating whether or not the position is fixed, and other information. At step S 805 , the information extractor  104  generates (or updates) an information table based on the pieces of information extracted from the EIR. 
         [0086]    If the time T (sec) has elapsed from the transmission of the inquiry signal (S 806 : yes), at step S 807  the communication controller  103  determines whether or not an EIR(s) has been received. If an EIR(s) has not been received (S 807 : no), this operation is finished. If an EIR(s) has been received (S 807 : yes), the information extractor  104  receives a notice to the effect that the time T has elapsed from the communication controller  103 . At step S 808 , the information extractor  104  supplies the information table generated at step S 805  to the position determining module  105 . And the position determining module  105  determines whether or not the information table received from the information extractor  104  contains positional information of a fixed apparatus. If the information table contains positional information of a fixed apparatus (S 808 : yes), at step S 809  the position determining module  105  performs the above-described position determination processing using the (pieces of) positional information of the fixed apparatus and supplies positional information indicating a determined position of the communication apparatus  100  to the memory  107 . If the information table contains only one piece of positional information indicating a fixed position, the position determining module  105  employs, as a position of the communication apparatus  100 , the position indicated by the one piece of positional information and supplies it to the memory  107 . 
         [0087]    At steps S 808  and S 809 , if at least one EIR contains positional information indicating a fixed position, a position selection screen for selection of one of plural pieces of positional information including (pieces of) positional information of a fixed apparatus and pieces of positional information of non-fixed apparatus may be displayed on the display device  109  so that the position of the communication  100  will be determined based on a user operation command through the position selection screen. The display device  109  displays the position selection screen in such a display form that the user can recognize which of the plural pieces of positional information is positional information of a fixed apparatus. 
         [0088]    On the other hand, if the information table does not contain positional information of a fixed apparatus (S 808 : no), at step S 810  the position determining module  105  performs the same position determining processing as performed at step S 708  (see  FIG. 9 ) and supplies positional information indicating a determined position of the communication apparatus  100  to the memory  107 . 
         [0089]    At step S 811 , the memory  107  stores the positional information received from the position determining module  105  (permanent of temporary storage) and supplies the positional information to the video processor  108 . At step S 812 , the video processor  108  generates a positional information display screen based on the positional information received from the memory  107  and the display device  109  displays the screen generated by the video processor  108 . The operation of the communication apparatus  100  is thus completed. 
         [0090]    With the above operation, if received EIRs include an EIR(s) transmitted from a fixed apparatus, the communication apparatus  100  can preferentially select the (pieces of) positional information of the fixed apparatus and determine the position of the communication apparatus  100  using that (those pieces of) positional information. Therefore, if an apparatus capable of sending an EIR in response to inquiry signal is installed at such a particular location as a sightseeing spot, the communication apparatus  100  is capable of acquiring correct positional information of the particular location. 
         [0091]    Although the embodiments according to the present invention have been described above, the present invention is not limited to the above-mentioned embodiments but can be variously modified. Constituent components disclosed in the aforementioned embodiments may be combined suitably to form various modifications. For example, some of all constituent components disclosed in the embodiments may be removed or may be appropriately combined. 
         [0092]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.