JP2011010001A - Portable terminal, communication system, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display content of a portable terminal on a television receiver.SOLUTION: The portable terminal is provided with a broadcast wave transmitting/receiving part which transmits a television broadcast radio signal of weak radio waves modulated using the content of the portable terminal, on an available channel of television broadcast. A transmission terminal 100 transmits the content using the available channel of the television broadcast, the content can be viewed without adding a special function to the television receiver. Furthermore, the content is also simultaneously shared by a plurality of reception terminals.

Description

  The present invention relates to a mobile terminal, a communication system, and a communication method.

  Mobile terminals include mobile phones and mobile terminal devices (PDAs). Taking a mobile phone as an example, in order to transmit images, document data, etc. from a mobile phone to another mobile phone, ADSL, CATV, broadband wired internet access and wireless access using optical lines, and short-distance communications such as IR (infrared) and Bluetooth (registered trademark) were used. In addition, in order to enlarge and display small characters such as e-mails displayed on a mobile phone, the content displayed on the mobile phone is converted into TV display content, and IrDA, Bluetooth (registered trademark), wireless LAN, etc. A technology for transmitting to a large screen display device, for example, a TV (television receiver) using a communication control method for short-range wireless connection or a communication control method for wired connection such as USB (registered trademark) or IEEE1394, and displaying on the TV. Has been proposed.

JP 2003-244289 A

  In the short-range communication according to the above-described conventional technique, one-to-one communication is possible, but there is a problem that a plurality of people cannot share content in real time. In addition, when a TV broadcast wave is used, there is a possibility that it may be browsed by an unspecified number of people, leading to information leakage. In addition, when transmitted in a specific format, browsing may not be possible.

  The present invention has been made in consideration of such circumstances, and the purpose thereof is to easily transmit / receive content, to prevent or reduce the risk of secret leakage, and to content on a plurality of portable terminals. It is an object of the present invention to provide a mobile terminal, a communication system, and a communication method that can easily share information.

  In order to solve the above-described problem, the present invention includes a broadcast wave transmission / reception unit that transmits a TV broadcast radio signal of a weak radio wave modulated using content of a mobile phone using an empty TV broadcast channel. It is a terminal.

  According to the present invention, in the above invention, the channel of the TV broadcast wave signal is scanned to search for an empty channel that is not used for TV broadcasting, and the information on the empty channel searched by the empty channel search unit Transmitting channel information notifying means for transmitting to other portable terminals as transmission channel information, and a TV broadcasting radio for transmitting a TV broadcasting radio signal modulated using content data on an empty channel searched by the empty channel searching means. A portable terminal comprising a signal transmission means.

  According to the present invention, in the above invention, in place of the empty channel search means, position information means for acquiring position information indicating a current position, and broadcast station information of a television broadcast wave for each region according to the position information. Based on broadcast station information storage means to be stored, position information acquired by the position information means, and broadcast station information stored in the broadcast station information storage means, an empty channel that is not used for television broadcasting is specified. The transmission channel information notifying unit notifies the other portable terminal of the information on the empty channel specified by the empty channel specifying unit as transmission channel information.

  The present invention provides the empty channel changing means for changing the empty channel for transmitting the content at a predetermined timing in the transmission process of the television broadcast radio signal modulated using the content data by the television broadcast radio signal transmitting means in the above invention. The transmission channel information notifying unit notifies the transmission channel information to another portable terminal every time the empty channel is changed by the empty channel changing unit.

  In the above invention, the present invention further comprises encryption means for encrypting a television broadcast radio signal modulated using content data, transmitted by the television broadcast radio signal transmission means, wherein the transmission channel information notification means is Along with the transmission channel information, the encryption key used for encryption by the encryption means is notified to another portable terminal.

  In the above invention, the present invention further comprises short-range communication means for communicating with other portable terminals by short-range communication, and portable terminal storage means for storing other portable terminals that share content in advance, The information notifying means notifies the other mobile terminal of the transmission channel information by the short-range communication means when the short-range communication means detects another mobile terminal stored in the mobile terminal storage means. It is characterized by that.

  In order to solve the above-described problem, the present invention is not used for television broadcasting by a television broadcast receiving unit that receives a television broadcast wave signal, a communication unit that communicates with another portable terminal, and the communication unit. When transmission channel information indicating an empty channel is received, the television broadcast reception unit is activated, a setting unit that sets the transmission channel notified by the transmission channel information as a reception channel, and the reception set by the setting unit A portable terminal comprising: presentation means for presenting content included in a television broadcast radio signal from the other portable terminal received by the television broadcast receiving means on a channel.

  According to the present invention, when transmission channel information is received by the communication means in the above invention, a shortcut icon for starting the television broadcast receiving means on the reception channel set by the setting means is created on the standby screen. An icon creating means is further provided.

  The present invention is the above invention, further comprising biometric authentication means for performing biometric authentication of the user, wherein the transmission channel information includes viewing user information capable of sharing content in addition to the empty channel, When the user who is biometrically authenticated by the biometric authentication unit matches the viewing user information, the content received by the television broadcast receiving unit is presented on the reception channel set by the setting unit. .

  According to the present invention, in the above invention, a television broadcast radio signal modulated using the content is encrypted with a predetermined encryption key, and the transmission channel information includes the encryption key in addition to the empty channel. And further comprising decryption means for decrypting the encrypted content received by the television broadcast receiving means on the reception channel set by the setting means, wherein the presenting means is set by the setting means The content included in the television broadcast radio signal received by the television broadcast receiving unit and decoded by the decoding unit via a reception channel is presented.

  In order to solve the above-described problem, the present invention is a communication system in which content of a transmission terminal is shared by a plurality of reception terminals, and the transmission terminal scans a channel of a television broadcast wave signal to Empty channel searching means for searching for empty channels not used for broadcasting, transmission channel information notifying means for notifying information of empty channels searched by the empty channel searching means to other portable terminals as transmission channel information, and content TV broadcast radio signal transmitting means for transmitting a TV broadcast radio signal modulated using data on an empty channel searched by the empty channel search means, and each of the plurality of receiving terminals receives a TV broadcast wave signal. TV broadcast receiving means for receiving, communication means for communicating with other portable terminals, When the transmission channel information from the transmission terminal is received by the means, the television broadcast reception means is activated, a setting means for setting the transmission channel notified by the transmission channel information as a reception channel, and setting by the setting means And a presenting means for presenting content included in a television broadcast radio signal from the transmitting terminal received by the television broadcast receiving means on the received channel.

  In order to solve the above-described problem, the present invention provides a communication method for sharing content of a transmission terminal among a plurality of reception terminals including a television broadcast reception unit, wherein the transmission terminal transmits a channel of a television broadcast wave signal. And searching for empty channels that are not used for television broadcasting, the transmitting terminal notifying the plurality of receiving terminals of information on the searched empty channels as transmission channel information, A transmitting terminal transmitting a television broadcast radio signal modulated using content data on an empty channel searched by the empty channel searching means, wherein the plurality of receiving terminals transmit a transmission channel from the transmitting terminal. Receiving information, and the plurality of receiving terminals transmit channel information from the transmitting terminal. When receiving, the step of activating the television broadcast receiving unit and setting the transmission channel notified by the transmission channel information as a reception channel; and the plurality of receiving terminals using the set reception channel in the television broadcast receiving unit Presenting content included in a television broadcast radio signal from the transmitting terminal received by the transmission terminal.

  According to the present invention, since broadcast waves are used, content can be easily transmitted and received without adding a special function to the receiving side. In addition, content can be shared by a plurality of portable terminals. In addition, since the transmission channel is switched, secret leakage can be prevented or reduced.

It is a block diagram which shows the external appearance structure of the mobile telephone by 1st Embodiment of this invention. FIG. 3 is a block diagram illustrating a configuration of a mobile phone on the content transmission side according to the first embodiment. It is a schematic diagram which shows the condition where a content is shared using the mobile telephone by this 1st Embodiment. It is a conceptual diagram which shows an example of the email for the transmission terminal by this 1st Embodiment to notify empty channel information. It is a schematic diagram which shows the example of a screen in the receiving terminal which received the mail by this 1st Embodiment. FIG. 6 is a sequence diagram for explaining the operation of the mobile phone according to the first embodiment. It is a block diagram which shows the structure of the transmission terminal by this 2nd Embodiment. It is a sequence diagram for demonstrating operation | movement of the mobile telephone by this 2nd Embodiment. It is a sequence diagram for demonstrating operation | movement of the mobile telephone by this 3rd Embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

A. First Embodiment FIG. 1 is a block diagram showing an external configuration of a mobile phone according to a first embodiment of the present invention. In the figure, the mobile phone 1 is provided with a liquid crystal panel or an organic EL (Electro-Luminescence) panel, and is selected on various setting screens, a main display unit 11 for displaying TV broadcasts, mails, etc., various setting screens, and the like. A cursor key 12 for moving the cursor, a decision key 13 for determining a selection item, various keys 14 including a numeric keypad, *, #, etc., a speaker 15 for outputting a call and TV broadcast sound, and a microphone 16 used for sound collection during a voice call , LCD panel or organic EL (Electro-Luminescence) panel, when the mobile phone 1 is closed, the sub display unit 17 displays the date and time, incoming mail, etc., and shoots the subject to generate image data A camera 18 and an LED light 19 functioning as a light source for photographing with the camera It is equipped with a television signal receiving antenna 20 for the reception of television broadcasting.

FIG. 2 is a block diagram showing a configuration of the mobile phone 100 on the content transmission side according to the first embodiment. The mobile network communication unit 101 performs data communication such as voice call and mail via the mobile network. The mobile network communication control unit 102 controls the mobile network communication unit 101 under the control of the control unit 121. The broadcast wave transmission / reception unit 103 transmits and receives a television broadcast wave. In particular, in the first embodiment, a search is made for an empty channel that is not used for broadcasting, and the content is transmitted to another mobile phone using the television broadcast wave. To do.
The broadcast wave transmission / reception unit 103 includes a tuner 1031, an OFDM (Orthogonal Frequency Division Multiplexing) demodulation circuit 1032, a decoder 1033, an encode 1034, an OFDM modulation circuit 1035, and a broadcast wave transmission circuit 1036. . The tuner 1031 selects a one-segment broadcast by selecting the frequency of the broadcast signal received by the antenna. The tuner 1031 performs the above-described channel selection according to an operation input from the operation input unit 115 or an instruction from the empty channel search unit of the control unit 121.
The OFDM demodulation circuit 1032 demodulates the broadcast signal of the one-segment broadcasting and outputs it as a TS (Transport Stream) defined by the MPEG-2 (Moving Picture Expert Group-2) system. The decoder 1033 outputs video data, audio data, and character data by decoding the TS. The encoder 1034 outputs TS by encoding video data, audio data, and character data. The OFDM modulation circuit 1035 performs modulation by using the OFDM method, which is a modulation method used for one-segment broadcasting of TS. The broadcast wave transmission circuit 1036 receives the signal modulated by the OFDM modulation circuit 1035, converts it to a broadcast wave frequency, and transmits it via an antenna. The broadcast wave total receiving circuit 103 transmits a signal using a channel notified by the transmission channel information notification means at a frequency (UHF (Ultra High Frequency) or VHF (Very High Frequency)) used in digital terrestrial broadcasting. Do.
The ROM 104 stores programs executed by the control unit 121, various data, and the like. The RAM 105 stores various rewritable data.

  The Bluetooth (registered trademark) communication unit 106 transmits and receives data to and from other mobile phones that are close to each other in accordance with the Bluetooth (registered trademark) standard, which is one of short-range communications. In particular, in the first embodiment, it is used as one communication means for notifying vacant channel information indicating a channel when content is transmitted to another mobile phone using a television broadcast wave. The IR (infrared) communication unit 107 is also one of short-distance communications, and transmits and receives data to and from other mobile phones using infrared rays. In particular, in the first embodiment, similarly to the Bluetooth (registered trademark) communication unit 106, one communication for notifying free channel information indicating a channel when content is transmitted to another mobile phone through a television broadcast wave is performed. Used as a means.

  The vibration unit 108 notifies a mail or voice call by vibration. The display processing unit 109 controls display on the main display unit 110 and the sub display unit 111 under the control of the control unit 121. The voice processing unit 112 outputs the received voice data from the speaker 113 and converts the voice input from the microphone 114 into voice data and captures it in a voice call or the like. The operation input unit 115 is various keys 14 including the cursor key 12, the determination key 13, the numeric keypad, *, #, and the like shown in FIG. The input processing unit 116 processes the input from the operation input unit 115. The operation unit illumination 117 is disposed below each key of the operation input unit 115 and lights up during operation. The camera 118 corresponds to the camera 18 shown in FIG. The LED light 119 corresponds to the LED light 19 shown in FIG. The imaging processing unit 120 controls an imaging operation by the camera 118, capturing of a captured image, turning on / off of the LED light 119, and the like.

  The control unit 121 controls each unit described above. In particular, in the first embodiment, as an operation when transmitting content on a television broadcast wave, empty channel search means for searching for an empty channel of the television broadcast wave and the searched empty channel are notified as transmission channel information. Transmission channel information notifying means, and television broadcast radio signal transmitting means for performing broadcast transmission of content using a television broadcast wave signal. Note that the control unit 121 also includes means not shown in the figure for operations other than transmitting content by television broadcast waves, such as voice call means and imaging means.

As the cellular phone on the content receiving side, the same cellular phone 100 described in FIG. 2 can be used. 2 may be such that the control unit 130 does not execute the TV application, but the control unit of the mobile phone on the content receiving side can execute the TV application. Further, a television tuner may be provided instead of the broadcast wave transmitting / receiving unit 103 of FIG. That is, a mobile phone that does not transmit television broadcast waves may be used.
Further, the transmission terminal 100 may transmit a radio transmission wave to the television receiver. When the channel of the television receiver is matched with the channel through which the transmission terminal 100 transmits, the TV tuner of the television receiver picks up this radio transmission wave and performs processing such as demodulation. The television receiver displays the demodulated content image and emits sound.
Further, when the power of the television receiver is turned off, the power may be connected by a signal from the transmission terminal 100. For example, a remote control signal for connecting the power supply of the television receiver is transmitted from the IR communication unit of the transmission terminal. Similarly, the reception channel of the television receiver may be set by a signal from the transmission terminal 100.

  FIG. 3 is a schematic diagram illustrating a situation in which content is shared using the mobile phone according to the first embodiment. Four mobile phones are shown in total, and the names of the transmitting terminal 100 and the receiving terminals A to C are given to each of them. The transmission terminal 100 on the content transmission side receives transmission channel information for broadcasting content using a mail via a mobile network or near field communication such as wireless LAN communication or Bluetooth (registered trademark) communication. 200-1, 200-2, and 200-3 are notified, and then the content is broadcast using a television broadcast signal. The content includes video, audio, data (text), video + audio, video + audio + data, and the like. Further, the content data may be stored in advance in the RAM 105, or may be capture data of the content currently displayed on the screen.

  The receiving terminals 200-1, 200-2, and 200-3 are transmission channels indicating channels through which content is broadcast by short-distance communication such as mail via a mobile network, wireless LAN communication, or Bluetooth (registered trademark) communication. When the information is received, the TV application is started, the received transmission channel (empty channel) is set as the reception channel, and the content transmitted by the transmission terminal 100 using the TV broadcast signal is received.

  FIG. 4 is a conceptual diagram showing an example of a mail for the transmission terminal according to the first embodiment to notify the transmission channel information. The mail notifying the transmission channel information includes “open TV” which is a command for instructing to start up the TV application of the receiving terminal, “Taroh” indicating the transmitting user, “to all user” indicating the receiver, It is sufficient that “ch23” indicating the transmission channel is indicated, and the description format is not limited thereto. Further, whether or not the mail is for notifying the transmission channel information can be determined by the mail content or the mail title.

  FIG. 5 is a schematic diagram illustrating a screen example on the receiving terminal that has received the mail according to the first embodiment. If the information received from the transmitting terminal is transmission channel information, the receiving terminal creates a shortcut icon 300 on the standby screen as shown in FIG. When the user of the receiving terminal selects the shortcut icon 300 and presses the enter key 13, as shown in FIG. 5B, a selection screen 301 consisting of options from who the connection request is and whether to connect. Is displayed. When the user of the receiving terminal selects “Yes” and presses the enter key 13, the TV application is activated and the operation proceeds to the TV broadcast receiving operation on the transmission channel. If “No” is selected, the screen returns to the standby screen.

Next, the operation of the first embodiment will be described.
FIG. 6 is a sequence diagram for explaining the operation of the mobile phone according to the first embodiment. First, the transmitting terminal 100 that wants to share content scans an empty channel of broadcast waves and notifies the receiving terminals 200-1 to 200-3 as transmission channel information to the receiving terminals 200-1 to 200-3 as transmission channel information (step Sa1). . Then, after a predetermined time has elapsed, the broadcast wave signal modulated using the content is broadcasted by the broadcast wave transmission / reception unit on an empty channel. That is, the content is converted into content for TV broadcasting and broadcast transmission is performed on an empty channel (step Sa2).

  If the received information is the transmission channel information, the receiving terminals 200-1 to 200-3 that have received the communication of the transmission channel create a shortcut icon on the standby screen as shown in FIG. When “Yes” is selected on the selection screen of (b), the TV application is activated (step Sa3), and the designated transmission channel is set as the reception channel (step Sa4). Then, the TV tuner receives a broadcast wave signal broadcast from the transmitting terminal and views the content.

  As described above, since the transmission terminal 100 transmits content using a TV broadcast empty channel, the reception terminal can view the content without adding a special function. In addition, content can be shared simultaneously by a plurality of receiving terminals.

B. Second Embodiment Next, a second embodiment of the present invention will be described.
FIG. 7 is a block diagram showing the configuration of the transmission terminal according to the second embodiment. It should be noted that parts corresponding to those in FIG. In the second embodiment, a GPS control unit is provided on the transmission terminal 100 side. The position information detection unit 122 detects position information using base station information of a mobile network or GPS (Global Positioning System). In addition, the RAM 105 stores broadcast station information (used channels, empty channels) for each region according to the position information. The control unit 121 obtains the position information that the position information means controls and acquires the position information acquisition unit 122, and broadcast station information stored in the RAM 105 (broadcast station information storage means), and is not used for broadcasting. The empty channel specifying means determines the channel as a content transmission channel. The transmission channel information notifying means notifies the transmission channel information as described with reference to FIG. In addition, as described with reference to FIG. 2, the control unit 121 includes means not shown in the figure for operations other than transmitting content by television broadcast waves, such as voice call means and imaging means.

Next, the operation of the second embodiment will be described.
FIG. 8 is a sequence diagram for explaining the operation of the mobile phone according to the second embodiment. First, the transmitting terminal 100 that wants to share content detects position information by the position information acquisition unit 122 (step Sb1), and is not used for broadcasting from the position information and the broadcast station information stored in the RAM 105. The vacant channel is determined as the transmission channel, and the transmission channel information is notified to the receiving terminals 200-1 to 200-3 by mail or near field communication (step Sb2). Then, after a predetermined time has elapsed, the broadcast wave signal modulated using the content is broadcasted by the broadcast wave transmission / reception unit 103 via an empty channel (step Sb3).

  If the received information is the transmission channel information, the receiving terminals 200-1 to 200-3 that have received the communication of the transmission channel create a shortcut icon on the standby screen as shown in FIG. When “Yes” is selected on the selection screen of (b), the TV application is activated (step Sb4), and the designated transmission channel is set as the reception channel (step Sb5). The TV tuner 203 receives a broadcast wave signal broadcast from the transmission terminal 100 and views the content.

  Thus, since the transmitting terminal 100 determines an empty channel according to the position information, it is not necessary to search for an empty channel, and the search time can be reduced.

C. Third Embodiment Next, a third embodiment of the present invention will be described.
In the present invention, the content is shared with other mobile phones by broadcasting the content using a television broadcast wave signal. Since a TV broadcast wave signal uses an unused channel that is not normally used, it is unlikely to be viewed by an unspecified number of people, but it is not always viewed. Therefore, the third embodiment is characterized in that information leakage is prevented by changing the channel for transmitting content at a predetermined time, such as page feed timing. The configuration of the mobile phone is the same as that described in Embodiment 1 with reference to FIG.

  FIG. 9 is a sequence diagram for explaining the operation of the mobile phone according to the third embodiment. First, the transmitting terminal 100 that wants to share content scans a vacant channel of broadcast waves and notifies the receiving terminals 200-1 to 200-3 of transmission channel information by mail or near field communication (step Sc1). Then, after a predetermined time has elapsed, the broadcast wave signal modulated using the content is broadcasted by the broadcast wave transmitting / receiving unit 103 via an empty channel (step Sc2).

  If the received information is the transmission channel information, the receiving terminals 200-1 to 200-3 that have received the communication of the transmission channel create a shortcut icon on the standby screen as shown in FIG. When “Yes” is selected on the selection screen of (b), the TV application is activated (step Sb3), and the designated transmission channel is set as the reception channel (step Sb4). The TV tuner 203 receives a broadcast wave signal broadcast from the transmission terminal 100 and views the content.

  The transmission terminal 100 determines whether or not a predetermined time has elapsed after the broadcast of the content (step Sc5), and scans another empty channel of the broadcast wave again every time the predetermined time elapses, and transmits the transmission channel information by e-mail or near. Receiving terminal 200-1 to 200-3 is notified by distance communication (step Sc6). Then, after a predetermined time elapses, the television broadcast wave signal modulated using the content is broadcasted on an empty channel changed by the broadcast wave transmitting / receiving unit 103 (step Sc7).

  Receiving terminals 200-1 to 200-3 that have received notification of the transmission channel set the designated transmission channel as the reception channel if the received information is transmission channel information (step Sc8). The TV tuner 203 receives a broadcast wave signal broadcast from the transmission terminal 100 and views the content.

  As described above, since the transmission terminal 100 changes the channel and transmits the content every time a predetermined time elapses, it is possible to prevent or reduce the possibility of secret leakage to a third party who does not receive the empty channel information.

  In the first to third embodiments described above, the receiving terminal 200 is further provided with means for performing biometric authentication, and the transmitting terminal 100 transmits the transmission channel information and the viewing user information together and receives them. In the receiving terminal 200, viewing of content may be permitted if the user who has been biometrically authenticated matches the viewing user information. Since personal identification by biometric authentication is a well-known technique, description thereof is omitted.

  Further, in the first to third embodiments described above, the TV broadcast wave signal transmitted from the transmission terminal 100 is further encrypted, and the encryption key is transmitted to the reception terminal 200 together with the transmission channel information. The television broadcast wave signal may be restored with the encrypted key and the content may be viewed. Note that information encryption and decryption are well-known techniques, and thus description thereof is omitted.

  In the first to third embodiments described above, when the transmission channel information is notified, a shortcut icon is displayed on the standby screen, and a selection screen for determining whether to start the TV application is displayed. However, the present invention is not limited to this, and a TV application may be automatically started when transmission channel information is notified.

  In addition, when a receiving terminal 200 that may share content in advance is registered in the transmitting terminal 100 and the registered receiving terminal 200 is detected by short-range communication (Bluetooth (registered trademark) or the like), the corresponding reception is performed. The transmission channel information may be transmitted to the terminal 200 by the short-range communication used for communication, and the content may be broadcast by an empty channel.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 100 Transmission terminal 200 Reception terminal 101,201 Mobile network communication part 102,202 Mobile network communication control part 103 Broadcast wave transmission / reception part 104,204 ROM
105, 205 RAM
106, 206 Bluetooth (registered trademark) communication unit 107, 207 IR (infrared) communication unit 108, 208 Vibration unit 109, 209 Display processing unit 110, 210 Main display unit 111, 211 Sub display unit 112, 212 Audio processing unit 113, 213 Speaker 114, 214 Microphone 115, 215 Operation input unit 116, 216 Input processing unit 117, 217 Operation unit illumination 118, 218 Camera 119, 219 LED light 120, 220, Imaging processing unit 121, 221 Control unit 122 Position information detection unit 203 TV tuner

Claims (12)

  A portable terminal comprising: a broadcast wave transmission / reception unit that transmits a television broadcast radio signal of a weak radio wave modulated using content of a cellular phone using an empty channel of television broadcast. An empty channel search means for scanning a channel of a TV broadcast wave signal and searching for an empty channel that is not used for TV broadcasting,
Transmission channel information notifying means for notifying other portable terminals of information on empty channels searched by the empty channel searching means as transmission channel information;
The mobile terminal according to claim 1, further comprising: a television broadcast radio signal transmission unit that transmits a television broadcast radio signal modulated using content data on an empty channel searched by the empty channel search unit. Instead of the empty channel search means,
Position information means for acquiring position information indicating the current position;
Broadcast station information storage means for storing broadcast station information of TV broadcast waves for each region according to the position information;
Based on the position information acquired by the position information means and the broadcast station information stored in the broadcast station information storage means, further comprising: empty channel specifying means for specifying an empty channel that is not used for television broadcasting,
The transmission channel information notifying means notifies the information of the empty channel specified by the empty channel specifying means to other portable terminals as transmission channel information.
The mobile terminal according to claim 2. A vacant channel changing means for changing a vacant channel for transmitting content at a predetermined timing in the transmission process of the television broadcast radio signal modulated using content data by the television broadcast radio signal transmitting means;
The transmission channel information notification means notifies the transmission channel information to another portable terminal every time an empty channel is changed by the empty channel change means.
The portable terminal according to claim 2 or 3, wherein Further comprising encryption means for encrypting a television broadcast radio signal modulated using content data, transmitted by the television broadcast radio signal transmission means,
The transmission channel information notification means notifies the portable key together with the transmission channel information of the encryption key used for encryption by the encryption means.
The mobile terminal according to claim 2, wherein the mobile terminal is a mobile terminal. Short-range communication means for communicating with other mobile terminals by short-range communication;
Portable terminal storage means for storing other portable terminals that share content in advance,
The transmission channel information notification means detects the transmission channel information by the short-range communication means when another short-distance communication means detects another portable terminal stored in the portable-terminal storage means. To notify,
The portable terminal according to claim 2, wherein the portable terminal is a portable terminal. A television broadcast receiving means for receiving a television broadcast wave signal;
Communication means for communicating with other mobile terminals;
Setting that sets the transmission channel notified by the transmission channel information as the reception channel when the transmission channel information indicating an empty channel not used for the television broadcast is received by the communication unit Means,
A portable terminal comprising: presentation means for presenting content included in a television broadcast radio signal from the other portable terminal received by the television broadcast receiving means on the reception channel set by the setting means.   When the transmission channel information is received by the communication means, it further comprises an icon creating means for creating a shortcut icon on the standby screen for starting the television broadcast receiving means on the reception channel set by the setting means. The mobile terminal according to claim 7. Further comprising biometric authentication means for performing biometric authentication of the user,
The transmission channel information is:
In addition to the vacant channel, including viewing user information that can share content,
The presenting means is
When the user who is biometrically authenticated by the biometric authentication unit matches the viewing user information, the content received by the television broadcast receiving unit is presented on the reception channel set by the setting unit.
The mobile terminal according to claim 7 or 8, characterized in that. The TV broadcast radio signal modulated using the content is
It is encrypted with a predetermined encryption key,
The transmission channel information is:
In addition to the empty channel, the encryption key is included,
Further comprising decryption means for decrypting the encrypted content received by the television broadcast reception means on the reception channel set by the setting means;
The presenting means is
Presenting the content included in the television broadcast radio signal received by the television broadcast receiving means on the reception channel set by the setting means and decoded by the decoding means;
The mobile terminal according to claim 7, wherein the mobile terminal is a mobile terminal. A communication system in which content of a transmitting terminal is shared by a plurality of receiving terminals,
The transmitting terminal is
An empty channel search means for scanning a channel of a TV broadcast wave signal and searching for an empty channel that is not used for TV broadcasting,
Transmission channel information notifying means for notifying other portable terminals of information on empty channels searched by the empty channel searching means as transmission channel information;
A television broadcast radio signal transmitting means for transmitting a television broadcast radio signal modulated using content data on an empty channel searched by the empty channel search means,
Each of the plurality of receiving terminals is
A television broadcast receiving means for receiving a television broadcast wave signal;
Communication means for communicating with other mobile terminals;
When transmission channel information from the transmission terminal is received by the communication unit, the television broadcast reception unit is activated, and a setting unit that sets the transmission channel notified by the transmission channel information as a reception channel;
And a presenting means for presenting content included in a television broadcast radio signal from the transmitting terminal received by the television broadcast receiving means on the reception channel set by the setting means. A communication method for sharing content of a transmission terminal among a plurality of reception terminals including a television broadcast reception unit,
The transmitting terminal scans a channel of a television broadcast wave signal and searches for an empty channel that is not used for television broadcasting; and
The transmitting terminal notifying the plurality of receiving terminals as information of the searched empty channel as transmission channel information;
The transmitting terminal transmitting a television broadcast radio signal modulated using content data on an empty channel searched by the empty channel searching means; and
The plurality of receiving terminals receiving transmission channel information from the transmitting terminal;
When the plurality of receiving terminals receive transmission channel information from the transmitting terminal, the television broadcast receiving unit is activated, and the transmission channel notified by the transmission channel information is set as a reception channel;
The plurality of receiving terminals presenting content included in a television broadcast radio signal from the transmitting terminal received by the television broadcast receiving unit on the set reception channel.

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