WO2013132745A1 - 放送システム、それに用いる送信機及び受信機、受信再生方法及びプログラム、並びに通信方法 - Google Patents
放送システム、それに用いる送信機及び受信機、受信再生方法及びプログラム、並びに通信方法 Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
- H04N21/238—Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams
- H04N21/2383—Channel coding or modulation of digital bit-stream, e.g. QPSK modulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/53—Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers
- H04H20/57—Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers for mobile receivers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H60/00—Arrangements for broadcast applications with a direct linking to broadcast information or broadcast space-time; Broadcast-related systems
- H04H60/02—Arrangements for generating broadcast information; Arrangements for generating broadcast-related information with a direct linking to broadcast information or to broadcast space-time; Arrangements for simultaneous generation of broadcast information and broadcast-related information
- H04H60/07—Arrangements for generating broadcast information; Arrangements for generating broadcast-related information with a direct linking to broadcast information or to broadcast space-time; Arrangements for simultaneous generation of broadcast information and broadcast-related information characterised by processes or methods for the generation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
- H04N21/438—Interfacing the downstream path of the transmission network originating from a server, e.g. retrieving encoded video stream packets from an IP network
- H04N21/4383—Accessing a communication channel
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
- H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
- H04N21/234—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
- H04N21/2343—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements
- H04N21/234327—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements by decomposing into layers, e.g. base layer and one or more enhancement layers
Definitions
- the present invention relates to a broadcasting system to which terrestrial digital broadcasting is applied, a transmitter and a receiver used therefor, a broadcasting method and a program, and a reception reproduction method and a program.
- Broadcasting of contents such as news and regional information by multimedia broadcasting for mobile terminals and Area One Seg using technology of Terrestrial Digital Broadcasting is under consideration. For example, in a fixed broadcasting area centered on each station, broadcast unique content for each station (sightseeing information around the station, introduction of stores, etc.) and content common to all stations (for example, news) at regular time intervals. It is considered to broadcast on.
- multimedia broadcasting for mobile terminals and Area One Seg a large number of empty channels are prepared, and the reception status does not depend on the number of receivers in the broadcasting area, which is suitable for the distribution of news and regional information.
- multimedia broadcasting for mobile terminals and area one seg information is unilaterally distributed, and handover between areas with different broadcast frequencies (channels) is not assumed. For this reason, when moving across a plurality of broadcast areas, it is necessary to search for available channels in the destination broadcast area. While such a channel search is being performed, broadcast content cannot be received at the mobile station.
- the receiving apparatus described in Patent Document 1 includes information on adjacent communities adjacent to the community corresponding to the current position of the receiver, and information on channels broadcast in each community, and is broadcast in adjacent communities. By selecting a channel and determining whether or not a broadcast signal can be received, it is possible to quickly determine a receivable channel.
- the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a broadcasting system that does not cause missing content to be reproduced even when moving to a different broadcasting area.
- the broadcasting system includes a transmitter and a receiver, and broadcasts data including content from the transmitter to the receiver.
- a transmitter is provided for each broadcast area where transmission signals of one channel or more can be received, and an input unit for inputting a transport stream of a data frame corresponding to the content and a dummy data frame unrelated to the content are generated.
- a processing unit that generates a transmission signal including a dummy broadcast frame including only dummy data frames, and a transmission unit that transmits the transmission signal through a channel determined for each broadcast area.
- the receiver includes a receiving unit that receives a transmission signal of the selected channel, a decoding unit that decodes the transmission signal received by the receiving unit, a reproducing unit that reproduces a data frame decoded by the decoding unit, A channel search unit that measures reception strength of transmission signals of channels corresponding to different broadcast areas at a timing at which a dummy broadcast frame is received, and determines a channel to be selected based on the reception strength.
- the channel search is performed during the reception of the dummy data, it is possible to eliminate the possibility that the content to be reproduced is lost even when the receiver moves across the broadcast area.
- FIG. 1 is an explanatory diagram showing the overall configuration of the broadcast system in the present embodiment.
- FIG. 2 is a block diagram showing the configuration of each part of the broadcast system in the present embodiment.
- FIG. 3 is a block diagram illustrating a configuration of a signal conversion unit of the transmitter according to the present embodiment.
- FIG. 4 is an explanatory diagram showing a configuration of an OFDM output frame in which a dummy frame is inserted in the present embodiment.
- FIG. 5 is an explanatory diagram showing the list contents of the representative channel information in the present embodiment.
- FIG. 6 is a flowchart showing the operation of the receiver in this embodiment.
- FIG. 7 is a flowchart showing a channel search operation in the present embodiment.
- FIG. 8 is an explanatory diagram showing timing for performing channel search in the receiver in this embodiment.
- FIG. 9 is an explanatory diagram showing how the receivable area varies in the present embodiment.
- FIG. 10 is an explanatory diagram showing a configuration of a broadcasting system in
- One aspect of the present invention is a broadcasting system, which includes a transmitter and a receiver, and broadcasts data including content from the transmitter to the receiver.
- a transmitter is provided for each broadcast area where transmission signals of one channel or more can be received, and an input unit for inputting a transport stream of a data frame corresponding to the content and a dummy data frame unrelated to the content are generated.
- a processing unit that generates a transmission signal including a dummy broadcast frame including only dummy data frames, and a transmission unit that transmits the transmission signal through a channel determined for each broadcast area.
- the receiver includes a receiving unit that receives a transmission signal of the selected channel, a decoding unit that decodes the transmission signal received by the receiving unit, a reproducing unit that reproduces a data frame decoded by the decoding unit, A channel search unit that measures reception strength of transmission signals of channels corresponding to different broadcast areas at a timing at which a dummy broadcast frame is received, and determines a channel to be selected based on the reception strength.
- the transmitter of the transmitter may further transmit a timing signal that is period information for inserting the dummy data frame
- the channel search unit of the receiver detects and selects the dummy broadcast frame.
- the channel to be tuned may be determined, and then the channel to be tuned may be determined at the timing when the dummy broadcast frame is received based on the timing signal without detecting the dummy broadcast frame.
- the dummy data frame may be inserted into the transport stream while common content is being transmitted in a plurality of transmission areas. As a result, it is possible to switch the reception channel to a different broadcast area without causing the content being viewed to be missing.
- F ⁇ I where F is the number of dummy data frames inserted and I is the interleave length in time interleaving. This makes it possible to reliably generate a dummy broadcast frame that includes only dummy data frames.
- the receiver may store a list of candidate channel information indicating channels that can be received in the adjacent broadcasting area for each broadcasting area, and the channel search unit detects a dummy broadcasting frame.
- the reception strength of the received signal by the candidate channel may be measured, and the channel to be selected may be determined based on the determination result of reception availability.
- the broadcasting system further includes a receiving unit that receives reception intensity information from a receiver, an intensity information collecting unit that collects reception intensity information for each broadcasting area, and insertion of dummy data frames according to fluctuations in the reception intensity information.
- the transmitter may comprise a dummy cycle determining unit for determining an interval, and a transmitter control unit having a transmitter for transmitting insertion interval information indicating the determined insertion interval of the dummy data frame to the transmitter. Then, when the insertion interval information is received, the insertion interval of the dummy frame may be updated.
- Another aspect of the present invention is a transmitter in the above broadcasting system, and yet another aspect is a receiver in the above broadcasting system.
- a transmitter for each broadcast area in which a transmission signal of one channel or more can be received, and reception is performed by receiving and reproducing a transmission signal including content broadcast from the transmitter.
- a reproduction method for receiving a transmission signal of a selected channel, a decoding step for decoding a transmission signal received by a reception unit, and a reproduction step for reproducing a data frame decoded by the decoding unit And a channel search step for measuring the reception strength of transmission signals of channels corresponding to different broadcast areas at the timing when a dummy broadcast frame unrelated to the content is received, and determining a channel to be selected based on the reception strength.
- Still another aspect of the present invention is a reception program characterized by causing a receiver to execute the above reception reproduction method by being executed by the receiver.
- Still another aspect of the present invention is a communication method that includes a transmitter and a receiver, and broadcasts data including content from the transmitter to the receiver.
- this transmission method at the transmitter, an input step of inputting a transport stream of a data frame corresponding to the content, a dummy frame generation step of generating a dummy data frame unrelated to the content, and a transport stream are multiplexed.
- a re-multiplexing step for inserting a dummy data frame and a process including time interleaving for the transport stream multiplexed in the re-multiplexing step, and a transmission signal including a dummy broadcast frame consisting only of dummy data frames
- a transmission step of transmitting a transmission signal through a channel determined for each broadcast area, and a reception step of receiving a transmission signal of the selected channel at the receiver, and a reception step Decodes the received transmission signal The reception strength of the transmission signal of the channel corresponding to the different broadcast area is measured at the timing when the dummy broadcast frame is received and the reproduction step of reproducing the data frame decoded in the decoding step.
- a channel search step for determining a channel to be tuned based on. Even with this configuration, even when the receiver moves to a different broadcast area, there is no loss of content played back by the receiver, and smooth handover can be realized.
- FIG. 1 is an explanatory diagram showing the overall configuration of the broadcasting system of the present embodiment.
- the broadcasting system includes a plurality of transmitters 10 and a plurality of receivers 30, and the transmitters 10 and the receivers 30 communicate wirelessly.
- the transmitter 10 can be installed at an arbitrary place, and the receiver 30 can move while receiving a transmission wave from the transmitter 10.
- each transmitter 10 a range 51 to 53 (broadcast areas A to C) that can be received by a transmission wave (a radio signal including content information) from each transmitter 10 is formed.
- a transmission wave a radio signal including content information
- each broadcast area one or a plurality of contents are simultaneously transmitted from the transmitter 10 via different channels (frequencies), and the user can view desired contents by selecting a channel with the receiver 30. it can.
- different channels are used in adjacent broadcast areas.
- the receiver 30 passes the route indicated by the dotted line in the figure, for example, after receiving the content broadcast on the channel f1, it is switched to the channel f2 when moving to an adjacent area, and then the channel It is switched to f3. In this way, by switching the reception channel in each reception area, the content can be continuously viewed on the moving receiver.
- the transmitter 10 is provided with a distribution schedule according to a predetermined schedule, and the content is broadcast within the corresponding broadcast area according to the schedule.
- FIG. 1 shows an example of a content distribution schedule.
- common content for example, news
- individual content for example, store introduction, facility introduction
- the broadcast start time and end time of the common content do not necessarily coincide with each other, and it is only necessary that the time zones during which the common content is broadcast overlap.
- the broadcast content is provided to the transmitter 10 from a server (not shown).
- the present invention is not limited to this, and each transmitter 10 may be configured to generate broadcast content.
- FIG. 1 only three broadcast areas A to C are shown, but it goes without saying that the number of broadcast areas may be four or more.
- the transmission of data from the transmitter 10 to the receiver 30 is based on the ISDB-T system compliant with the transmission system standard (ARIB STD-B31) for digital terrestrial television broadcasting. Therefore, in the following, the technical contents defined in this standard will be briefly described or omitted.
- the transmitter 10 includes an input unit 11, a signal conversion unit 12, and a transmission unit 13.
- the input unit 11 receives content information to be broadcast and outputs a video signal, an audio signal, and a data signal to the signal conversion unit 12.
- the input unit 11 generates a video signal by shooting and generates an audio signal by recording.
- the input unit 11 includes an operation unit, and generates a data signal based on a user operation on the operation unit. Further, the input unit 11 may acquire part or all of the video signal, the audio signal, and the data signal from the outside of the transmitter 10.
- the signal conversion unit 12 is an OFDM (Orthogonal Frequency Division Multiplexing) transmission signal (hereinafter referred to as “OFDM”) for transmitting the video signal, audio signal, and data signal input from the input unit 11 from the transmission unit 13 to the receiver 30. Also referred to as “transmitted wave”).
- OFDM Orthogonal Frequency Division Multiplexing
- the transmission unit 13 wirelessly transmits the OFDM transmission signal generated by the signal conversion unit 12.
- FIG. 3 is a diagram illustrating a configuration of the signal conversion unit 12 of the transmitter 10 according to the present embodiment.
- the signal conversion unit 12 includes an information source encoding unit 15, an MPEG-2 multiplexing unit 16, and a transmission path encoding unit 17.
- the information source encoding unit 15 includes a video encoding unit 18 that inputs and encodes a video signal, an audio encoding unit 19 that inputs and encodes an audio signal, and data that receives and encodes a data signal And an encoding unit 20.
- Video encoded data encoded by the video encoding unit 18, audio encoded data encoded by the audio encoding unit 19, and data encoded data encoded by the data encoding unit 20 are MPEG-2. Input to the multiplexing unit 16.
- the MPEG-2 multiplexing unit 16 multiplexes the video encoded data, the audio encoded data, and the data encoded data to form a transport stream (Transport Stream: hereinafter referred to as “TS”) defined by MPEG2 Systems. Output.
- Transport Stream hereinafter referred to as “TS”
- the transmission line encoding unit 17 receives one or a plurality of TSs, performs re-multiplexing, performs a plurality of transmission line encodings as one TS according to the service intention, and outputs the result as an OFDM transmission wave .
- the transmission path encoding unit 17 includes a TS remultiplexing unit 21 and an OFDM frame generation unit 22.
- the TS re-multiplexing unit 21 receives one or a plurality of TSs from the MPEG-2 multiplexing unit 16 and multiplexes and outputs data frames constituting the TS.
- the TS remultiplexing unit 21 includes a dummy frame generation unit 23 and a memory 24 for inserting a dummy data frame for channel search.
- the dummy frame generation unit 23 generates a plurality of dummy data frames at regular time intervals. This dummy frame is inserted between data frames corresponding to common content (for example, news) in FIG. The number of dummy data frames inserted at a time is determined according to the time interleave length in the interleave unit 26 described later. The dummy data frame has a predetermined bit pattern so that the receiver 30 can identify it. Information on the interval at which dummy data frames are inserted and the number of dummy data frames to be inserted at a time are provided in the memory 24 in the TS remultiplexing unit 21 and can be changed as appropriate.
- the TS re-multiplexing unit 21 converts a plurality of TSs input from the MPEG-2 multiplexing unit 16 into a burst signal format in units of 188 bytes using a clock four times the IFFT (Inverse FourierformTransform) sample clock. Convert, add outer code, and convert to single TS.
- IFFT Inverse FourierformTransform
- the OFDM frame generation unit 22 includes a hierarchical parallel processing unit 25, an interleaving unit 26, and an IFFT unit 27.
- the hierarchical parallel processing unit 25 divides the TS input from the TS remultiplexing unit 21 into layers according to the designation of the hierarchical information, and performs processing for each layer.
- the hierarchical parallel processing unit 25 performs processing including error correction coding, byte interleaving, convolutional coding, and carrier modulation for each layer.
- the hierarchical parallel processing unit 25 synthesizes the signals that have undergone the above processing for each hierarchy.
- the interleaving unit 26 performs time interleaving and frequency interleaving on the synthesized signal in order to effectively exhibit error correction coding capability against electric field fluctuations and multipath interference in mobile reception.
- the time interleave length I is set to 4, for example, and convolutional interleaving is performed on the data for the previous and subsequent four frames.
- the IFFT unit 27 adds a synchronous pilot signal, a TMCC (Transmission and Multiplexing Configuration and Control) signal, and an AC (Auxiliary Channel) signal to the interleaved signal, and configures and outputs an OFDM frame.
- the IFFT unit 27 performs an IFFT operation on the OFDM frame, generates an OFDM transmission signal, and outputs the OFDM transmission signal to the transmission unit 13.
- FIG. 4 is a diagram for explaining how the TS is multiplexed by the signal conversion unit 12.
- the frames multiplexed and output by the TS remultiplexing unit 21 include the data frame 151 input from the MPEG-2 multiplexing unit 16 and the dummy data frame generated by the dummy frame generating unit 23. 152.
- the frame output from the TS remultiplexing unit 21 is subjected to various processes in the hierarchical parallel processing unit 25, subjected to convolutional interleaving with a cycle of 4 in the interleaving unit 26, and output to the transmission unit 13 as an OFDM frame 153.
- the frame output from the TS remultiplexing unit 21 is subjected to various processes in the hierarchical parallel processing unit 25, subjected to convolutional interleaving with a cycle of 4 in the interleaving unit 26, and output to the transmission unit 13 as an OFDM frame 153.
- dummy data frames 152 are inserted from the dummy frame generation unit 23, and convolutional interleaving with a period of 4 is performed in the interleaving unit 26 (that is, interleaving using four frames before and after is performed).
- an OFDM frame (dummy OFDM frame) 154 composed only of dummy data frames is generated.
- the number F of dummy data frames inserted from the dummy frame generation unit 23 may be equal to or greater than the time interleave length I in the interleave unit 26 (F ⁇ I), and is not necessarily limited. It need not be the same as the interleave period.
- the dummy OFDM frame corresponds to a “dummy broadcast frame”.
- the receiver 30 is, for example, a mobile phone terminal, and includes a receiving unit 31, a decoding unit 32, a reproducing unit 33, a channel search unit 34, and a memory 35.
- the receiving unit 31 receives the OFDM transmission wave transmitted from the transmitting unit 13 of the transmitter 10.
- the receiving unit 31 measures the electric field strength of the OFDM transmission wave from the transmitter 10 and outputs the measurement result to the channel search unit 34.
- the decoding unit 32 decodes the OFDM transmission signal received by the receiving unit 31 and detects a dummy OFDM frame.
- the decoding unit 32 restores the TS by performing processing such as FFT (Fast Fourier Transform), frequency deinterleaving, time deinterleaving, and error correction on the received OFDM transmission signal.
- FFT Fast Fourier Transform
- the decoding unit 32 includes a dummy frame detection unit 36 that detects whether or not a dummy OFDM frame is included in the received OFDM transmission signal.
- the dummy data frame is composed of a predetermined bit pattern, and the dummy OFDM frame also has a predetermined bit pattern.
- the dummy frame detection unit 36 detects a dummy OFDM frame, the dummy frame detection unit 36 outputs a signal for starting a channel search to the channel search unit 34.
- the reproduction unit 33 reproduces the video signal, the audio signal, and the data signal obtained by the decoding in the decoding unit 32.
- the reproduction unit 33 includes a display and a speaker. The video signal and the data signal are displayed on the display, and the audio signal is output from the speaker.
- the decoded data signal may be used for controlling the reproduction unit 33.
- the channel search unit 34 performs a channel search for determining whether or not to select a channel in an adjacent broadcast area when a dummy OFDM frame is detected.
- the channel search unit 34 includes an adjacent area information storage unit 37 and a broadcast channel information storage unit 38.
- the adjacent area information includes, for each broadcast area, information on transmitters corresponding to adjacent (or partially overlapping) broadcast areas and candidate channels (electric fields that can be received in the adjacent broadcast area). Information on channels used for intensity measurement is stored in association with each other.
- the channel search unit 34 measures the electric field strength of the frequency indicated by the candidate channel in the adjacent broadcast area, and stores the obtained electric field strength information in the memory 35. The channel search unit 34 determines that the electric field strength obtained in this way is the strongest and has moved to an adjacent area when the threshold value is exceeded, and the content broadcast on the channel with the strongest electric field strength. Receive.
- the broadcast channel information storage unit 38 stores information on channels that can be received in each broadcast area, and switches the channels that can be received in each area by operating an operation unit (not shown) provided in the receiver 30. Playback output is possible.
- the memory 35 stores various information such as a measured value of the electric field strength of the candidate channel obtained by the channel search for the past several times, a broadcast area corresponding to the current position of the receiver, and a selected channel.
- broadcast area information corresponding to the current position of the receiver 30 may be extracted from the broadcast channel information storage unit 38.
- a GPS receiver (not shown) may be provided in the receiver 30, and a broadcast area corresponding to the current position may be specified based on position information obtained by the GPS receiver.
- FIG. 6 is a flowchart showing the reception / reproduction operation of the receiver 30.
- the receiver 30 receives the OFDM transmission signal from the transmitter 10 at the receiver 31 (S10).
- the dummy frame detection unit 36 provided in the decoding unit 32 of the receiver 30 determines whether or not the OFDM frame included in the received OFDM transmission signal is a dummy OFDM frame (S11).
- the decoding unit 32 decodes the received data frame to generate a TS frame, and outputs the TS frame to the playback unit 33, which is broadcasted.
- the content is reproduced (S12).
- the process proceeds to step S13 and a channel search described later is performed.
- FIG. 7 is a flowchart showing a channel search procedure.
- the channel search unit 34 reads out the broadcast area information corresponding to the current position of the receiver 30 from the memory 35, and selects the adjacent area candidate channels stored in the adjacent area information storage unit 37. Select (S20). Then, the receiver 30 measures the electric field strength at the frequency corresponding to the selected candidate channel, and the channel search unit 34 stores the measurement result in the memory 35 (S21). The selection of the main channel and the measurement of the electric field intensity are performed until the measurement of the electric field intensity of all candidate channels is completed (S22).
- the channel search unit 34 determines whether or not the electric field strength in the candidate channel exceeds a predetermined receivable threshold (S24).
- the receiving unit 31 selects the same channel as that before the channel search and continues receiving the same content as before (S26).
- FIG. 8 is an explanatory diagram showing how a channel search is performed when the receiver 30 moves from a certain broadcast area 51 to an adjacent broadcast area 52.
- the receiver 30 continuously receives the OFDM frame 153 corresponding to the content broadcast in the broadcast area 51 in the broadcast area 51 before moving. Then, when the receiver 30 detects the dummy OFDM frame, the receiver 30 performs the above-described channel search.
- the channel search channel search [1]
- the electric field strength from the adjacent broadcast area 52 is low, and the channel is not changed (the channel f1 corresponding to the broadcast area 51 before movement is selected).
- the receiver 30 selects the representative channel f2 in the broadcast area 52, and Reception of content broadcast in the broadcast area 52 is started.
- the receivable range varies. As shown in FIG. 9, the receivable range (viewable area) in a certain broadcast area is reduced from the area 60 a indicated by the dotted line to the area 60 b indicated by the solid line, and an overlapping portion 62 with the adjacent broadcast area 61 is formed. When the reduction is performed, there is a possibility that the dummy OFDM frame is not received when the receiver 30 passes through the overlapping portion 62. In such a case, the content to be reproduced is lost.
- the transmitter control device 70 collects the electric field strength information, and controls the dummy frame insertion interval in the transmitter 10 based on the obtained electric field strength information.
- the transmitter control device 70 includes a receiving unit 71, an intensity information collecting unit 72, a dummy cycle determining unit 73, and a transmitting unit 74.
- the receiving unit 71 is a wireless communication device compliant with, for example, the 3GPP standard, and receives the electric field strength data obtained by the channel search from the receiver 30 at regular time intervals.
- the intensity information collecting unit 72 collects the electric field intensity data received from the receiver 30 for each viewable area.
- the dummy period determining unit 73 takes statistics of the electric field strength information of each viewable area obtained in the strength information collecting unit 72 and determines the dummy frame insertion interval. For example, when the statistical value of the electric field strength received in a certain viewable area becomes small, it is determined that the overlapping portion with the adjacent viewable area has become small, and the dummy frame insertion interval is shortened. For such statistical processing, a known method such as calculating an average value of electric field strength or performing a known weighting operation can be used.
- the transmission unit 74 updates the dummy frame insertion interval by transmitting the dummy frame insertion interval information determined by the dummy cycle determination unit 73 to each transmitter 10. In this way, by taking statistics of the field strength information obtained at each receiver and determining the dummy frame insertion interval according to the size, it is possible to ensure dummy OFDM frames in the overlapping portions of adjacent viewable areas. Can be received.
- the receiver 30 is provided with a configuration for detecting a dummy OFDM frame.
- the number of detected OFDM frames is counted and a predetermined value (FIG. In the example of FIG. 8, when only m) is detected, it may be determined that the next received frame is a dummy OFDM frame and a channel search is performed. Thereby, the structure for detecting a dummy OFDM frame can be omitted.
- the channel search is performed every time the dummy OFDM frame is detected.
- the dummy OFDM frame insertion timing information may be notified from the transmitter 10 in advance by a broadcast wave or another line.
- the receiver 30 acquires dummy OFDM frame insertion timing information, and once the dummy OFDM frame can be detected, the dummy OFDM frame insertion timing is known thereafter, so that the channel search is performed at that timing. Is possible. This eliminates the need to detect a dummy OFDM frame every time, thereby reducing the channel search time.
- the common content and the local content are broadcast at regular intervals.
- the plurality of types of content may be broadcast by dividing into layers. Thereby, multiple types of content can be received simultaneously.
- the series of processes described above can be executed by hardware or software.
- the program can be executed by installing the program in a computer from a program storage medium storing a program constituting the software.
- the broadcasting system of the present invention has an effect of preventing loss of content to be reproduced and realizing stabilization of video, a broadcasting system applying terrestrial digital broadcasting, a transmitter and a receiver used therefor It is useful as a broadcasting device, a broadcasting method and program, and a reception and reproduction method and program.
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Abstract
Description
11 入力部
12 信号変換部
13 送信部
21 TS最多重部
22 OFDMフレーム生成部
23 ダミーフレーム生成部
26 インターリーブ部
30 受信機
31 受信部
32 復号部
33 再生部
34 チャネルサーチ部
36 ダミーフレーム検出部
37 隣接エリア情報記憶部
51、52、53 放送エリア
70 送信機制御装置
151 データフレーム
152 ダミーデータフレーム
153 OFDMフレーム
154 ダミーOFDMフレーム
Claims (12)
- 送信機と受信機とを含み、前記送信機から前記受信機に対してコンテンツを含むデータを放送する放送システムであって、
前記送信機は1チャネル以上の送信信号が受信可能とされている放送エリア毎に設けられ、
前記コンテンツに対応するデータフレームのトランスポートストリームを入力する入力部と、
前記コンテンツとは無関係のダミーデータフレームを生成するダミーフレーム生成部と、
前記トランスポートストリームを多重化するとともに、前記ダミーデータフレームを挿入する再多重部と、
前記再多重部で多重化されたトランスポートストリームに対して、時間インターリーブを含む処理を行い、前記ダミーデータフレームのみからなるダミー放送フレームを含む送信信号を生成する処理部と、
前記送信信号を放送エリア毎に定められたチャネルで送信する送信部とを備え、
前記受信機は、
選局されたチャネルの前記送信信号を受信する受信部と、
前記受信部にて受信した前記送信信号を復号する復号部と、
前記復号部にて復号された前記データフレームを再生する再生部と、
前記ダミー放送フレームが受信されるタイミングで、異なる放送エリアに対応するチャネルの送信信号の受信強度を測定し、当該受信強度に基づき選局すべきチャネルの決定を行うチャネルサーチ部と、を備えたことを特徴とする放送システム。 - 請求項1に記載の放送システムであって、
前記送信機の送信部は、さらに前記ダミーデータフレームを挿入する期間情報であるタイミング信号を送信し、
前記受信機のチャネルサーチ部は、前記ダミー放送フレームを検出して選局すべきチャネルの決定を行い、次いで、前記ダミー放送フレームを検出することなく、前記タイミング信号に基づき前記ダミー放送フレームが受信されるタイミングで前記選局すべきチャネルの決定を行うことを特徴とする放送システム。 - 前記ダミーデータフレームは、複数の前記送信エリアで共通のコンテンツが送信されている間に、前記トランスポートストリームに挿入されることを特徴とする、請求項1または2記載の放送システム。
- 前記ダミーデータフレームの挿入数をF、前記時間インターリーブにおけるインターリーブ長をIとしたときに、F≧Iであることを特徴とする請求項1または2記載の放送システム。
- 前記受信機は、放送エリア毎に、隣接する放送エリアで受信可能なチャネルを示す候補チャネル情報のリストを記憶しており、
前記チャネルサーチ部は、前記ダミー放送フレームを検出したときに、前記候補チャネルによる受信信号の受信強度を測定し、受信可否の判断結果に基づいて選局すべきチャネルを決定することを特徴とする、請求項1または2記載の放送システム。 - 前記受信機より受信強度情報を受信する受信部と、前記放送エリア毎に前記受信強度情報を収集する強度情報収集部と、前記受信強度情報の変動に応じて前記ダミーデータフレームの挿入間隔を決定するダミー周期決定部と、決定されたダミーデータフレームの挿入間隔を示す挿入間隔情報を、前記送信機に送信するための送信部とを有する送信機制御装置をさらに備え、
前記送信機では、前記挿入間隔情報を受信したときに、前記ダミーデータフレームの挿入間隔を更新することを特徴とする、請求項1または2記載の放送システム。 - 携帯端末向けマルチメディア放送又はエリアワンセグの放送を行なう請求項1乃至6のいずれか一項に記載の放送システム。
- 1チャネル以上の送信信号が受信可能とされている放送エリア毎に設けられ、受信機に対してコンテンツを含むデータを放送する送信機であって、
前記コンテンツに対応するデータフレームのトランスポートストリームを入力する入力部と、
前記コンテンツとは無関係のダミーデータフレームを生成するダミーフレーム生成部と、
前記トランスポートストリームを多重化するとともに、前記ダミーデータフレームを挿入する再多重部と、
前記再多重部で多重化されたトランスポートストリームに対して、時間インターリーブを含む処理を行い、前記ダミーデータフレームのみからなるダミー放送フレームを含む送信信号を生成する処理部と、
前記送信信号を放送エリア毎に定められたチャネルで送信する送信部とを備え、
前記受信機では、選局されたチャネルの前記送信信号を受信し、前記受信した前記送信信号を復号し、前記復号されたデータフレームを再生し、前記コンテンツと無関係のダミー放送フレームが受信されるタイミングで、異なる放送エリアに対応するチャネルの送信信号の受信強度を測定し、当該受信強度に基づき選局すべきチャネルの決定を行うことを特徴とする送信機。 - 1チャネル以上の送信信号が受信可能とされている放送エリア毎に送信機が設けられ、前記送信機から放送されたコンテンツを含む送信信号を受信して再生する受信機であって、
選局されたチャネルの前記送信信号を受信する受信部と、
前記受信部にて受信した前記送信信号を復号する復号部と、
前記復号部にて復号されたデータフレームを再生する再生部と、
前記コンテンツと無関係のダミー放送フレームが受信されるタイミングで、異なる放送エリアに対応するチャネルの送信信号の受信強度を測定し、当該受信強度に基づき選局すべきチャネルの決定を行うチャネルサーチ部とを含む受信機。 - 1チャネル以上の送信信号が受信可能とされている放送エリア毎に送信機が設けられ、前記送信機から放送されたコンテンツを含む送信信号を受信して再生する受信再生方法であって、
選局されたチャネルの前記送信信号を受信する受信ステップと、
前記受信部にて受信した前記送信信号を復号する復号ステップと、
前記復号部にて復号された前記データフレームを再生する再生ステップと、
前記コンテンツと無関係のダミー放送フレームが受信されるタイミングで、異なる放送エリアに対応するチャネルの送信信号の受信強度を測定し、当該受信強度に基づき選局すべきチャネルの決定を行うチャネルサーチステップとを含む受信再生方法。 - 受信機にて実行されることにより、該受信機に請求項10の受信再生方法を実行させることを特徴とする受信再生プログラム。
- 送信機と受信機とを含み、前記送信機から前記受信機に対してコンテンツを含むデータを放送する通信方法であって、
前記送信機にて、
前記コンテンツに対応するデータフレームのトランスポートストリームを入力する入力ステップと、
前記コンテンツとは無関係のダミーデータフレームを生成するダミーフレーム生成ステップと、
前記トランスポートストリームを多重化するとともに、前記ダミーデータフレームを挿入する再多重ステップと、
前記再多重ステップで多重化されたトランスポートストリームに対して、時間インターリーブを含む処理を行い、前記ダミーデータフレームのみからなるダミー放送フレームを含む送信信号を生成する処理ステップと、
前記送信信号を放送エリア毎に定められたチャネルで送信する送信ステップとを備え、
前記受信機にて、
選局されたチャネルの前記送信信号を受信する受信ステップと、
前記受信ステップにて受信した前記送信信号を復号する復号ステップと、
前記復号ステップにて復号された前記データフレームを再生する再生ステップと、
前記ダミー放送フレームが受信されるタイミングで、異なる放送エリアに対応するチャネルの送信信号の受信強度を測定し、当該受信強度に基づき選局すべきチャネルの決定を行うチャネルサーチステップと、を備えたことを特徴とする通信方法。
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JP2009005048A (ja) * | 2007-06-21 | 2009-01-08 | Mitsubishi Electric Corp | デジタル放送受信装置 |
JP2011507325A (ja) * | 2007-12-07 | 2011-03-03 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | 分散無線システムにおける多重チャネルサポート |
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JP2009005048A (ja) * | 2007-06-21 | 2009-01-08 | Mitsubishi Electric Corp | デジタル放送受信装置 |
JP2011507325A (ja) * | 2007-12-07 | 2011-03-03 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | 分散無線システムにおける多重チャネルサポート |
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