JP4626206B2 - Receiving device, program, and recording medium - Google Patents

Description

  The present invention relates to a technology for receiving terrestrial digital broadcasting.

  In the Japanese terrestrial digital broadcasting system, a 6 MHz transmission band corresponding to a conventional analog broadcasting channel can be divided into 13 segments, which can be bundled and divided into a maximum of 3 layers. This is a measure for effectively utilizing radio waves by freely combining high-definition broadcasting (HDTV) and normal-quality broadcasting (SDTV) that require a wide transmission band. For example, 12 segments are required for HDTV, but 4 segments are sufficient for SDTV. Therefore, for SDTV broadcasting, three different programs can be broadcast simultaneously on one channel.

  In the terrestrial digital broadcasting system, 12 segments out of 13 segments are used as fixed reception broadcasting, and the remaining one segment is reserved for mobile broadcasting. This digital broadcasting using one segment is called one segment broadcasting. Although the transmission bandwidth is about 300 kbps and only video with low resolution and bit rate can be transmitted, the development of new services that take advantage of the characteristics of mobile terminals and the like is expected (non-patent literature on terrestrial digital broadcasting systems) 1).

  In the broadcast for partial reception for mobile terminals using 1 segment and the broadcast for fixed reception using 12 segments, the information source coding system is changed (1 segment is H.264, 12 segments is MPEG-2), It is scheduled to change the information rate and transmit the same program (simultaneous broadcasting).

  In the future, it is also expected that unique contents and data broadcasts using the band of one segment part will be transmitted.

As described above, in the Japanese terrestrial digital broadcasting system, one segment is prepared for a mobile body, but it is also possible to audition a 12 segment program for fixed reception on a mobile body. As described above, when a mobile unit receives a program for fixed reception, a receiver adopting a diversity reception (space diversity) system is being put into practical use for the purpose of improving reception quality.
ARIB STD-B31 "Transmission Method for Digital Terrestrial Television Broadcasting" May 31, 2001

  As described above, broadcasts in one segment prepared for mobiles in the Japanese terrestrial digital broadcasting system include simultaneous broadcasting of programs for fixed reception, broadcasting of original content for mobiles, and data broadcasting.

  At this time, it is very convenient if the viewer can display the sub-screen using the one-segment broadcasting of another channel while the viewer listens to the 12-segment program for fixed reception. Even if a sub-screen is displayed on the screen for fixed reception broadcast in 12 segments using 1-segment simulcast on the same channel, providing convenience to the user as long as both are the same program There is no. If one-segment broadcasting is broadcasting of original content for mobiles or data broadcasting, a certain effect can be expected by displaying other information on a sub-screen superimposed on the program for fixed reception. However, the data provided by the same broadcasting station It is only broadcast, and it is difficult to completely respond to the user's preference. In this regard, if the data broadcast of another channel can be displayed on the child screen while the fixed reception program is displayed, the user can select the child screen according to his / her preference. For example, a professional baseball broadcast being broadcast on another channel while watching a TV drama can be displayed on a small screen.

  Conventionally, in order to simultaneously display a program of another channel on the screen, in addition to a tuner + demodulator for viewing a program for fixed reception, another tuner + demodulator configuration is required. It was necessary to select and synthesize the program.

  In order to achieve the above object, a receiving apparatus according to the present invention is a receiving apparatus that receives a signal modulated by a digital multi-level modulation method with a plurality of antennas and performs demodulation processing, and receives the signals from the plurality of antennas. The complex information indicating the signal point of the received signal is output, the transmission parameter describing the information necessary for demodulation is extracted from the received signal, the demodulating means for outputting, and the complex information input from the demodulating means, the user Judges whether the complex information of the partial segment related to the specified channel and the complex information of the partial segment related to another channel can be replaced, outputs the determination result, and replaces the complex information if it can be replaced Transmission parameter comparison means for replacing the transmission parameter of the partial segment to be transmitted, and the transmission parameter comparison means Of the complex information input from the demodulating means based on the obtained determination result, the combining means for replacing the complex information of the partial segment related to the channel specified by the user and the complex information of the partial segment of the other channel; According to the transmission parameter output from the transmission parameter comparison means, there is provided a demapping means for restoring bit data of the complex information input from the synthesis means.

  According to the receiving apparatus of the present invention, it is possible to display a one-segment broadcast of another channel on a small screen while listening to a program for fixed reception of a certain channel.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an example of an embodiment of the present invention.

  In FIG. 1, 101a is antenna means, 102a is tuner means, 103a is A / D conversion means, 104a is quadrature detection means, 105a is FFT calculation means, 106a is demodulation means, 107 is transmission parameter comparison means, and 108 is synthesis means. 109 are deinterleaving means, 110 is demapping means, 111 is bit interleaving means, and 112 is error correcting means.

  On the other hand, 101b is antenna means different from 101a, 102b is tuner means, 103b is A / D conversion means, 104b is quadrature detection means, 105b is FFT calculation means, and 106b is demodulation means.

  In this embodiment, it is assumed that the antenna means 101a receives a broadcast radio wave related to channel a from the A broadcast station, and the antenna means 101b receives a broadcast radio wave related to channel b from the B broadcast station.

  The antenna means 101a converts the broadcast wave of channel a transmitted from the A broadcast station into an electric signal and outputs it. The tuner unit 102a extracts a signal in a specific frequency band from the signal obtained from the antenna unit 101a, and converts the signal into a signal in a baseband or a constant frequency band. The A / D conversion means 103a converts the analog signal obtained from the tuner means into a digital signal.

  The orthogonal detection means 104a detects the OFDM transmission signal, calculates and corrects the frequency error between the transmission signal and the frequency reference signal of the demodulation means, calculates the frequency OFDM symbol period and the guard interval period, and calculates the OFDM symbol period. The signal is output. Further, the transmission mode of the OFDM transmission signal and the length of the guard interval period are also determined.

  The OFDM signal is composed of a guard interval period and an effective symbol period, and the guard interval period is obtained by adding the rear part of the effective symbol period as it is in front of the effective symbol period. That is, since the signal in the guard interval period is a copy of a part of the OFDM signal, there are portions where the same signal is repeatedly included in the OFDM symbol (effective symbol period + guard interval period). When the correlation value in the time direction of the OFDM signal is calculated, a high correlation is shown in accordance with the guard interval period, so the guard interval length, the guard ratio indicating the ratio between the effective symbol period and the guard interval period, and the transmission mode can be determined. . Then, the quadrature detection means extracts only the signal corresponding to the effective symbol period and sends it to the subsequent FFT calculation means, and outputs the mode and guard ratio information to the transmission parameter comparison means 107.

  The FFT calculation means 105a performs FFT calculation processing on the signal in the time domain of the OFDM symbol period obtained from the quadrature detection means 104a and converts it into a signal in the frequency domain.

  The demodulating means 106a demodulates a TMCC (Transmission and Multiplexing Configuration and Control) signal inserted in the OFDM signal, and obtains various parameter information of the OFDM transmission signal. This transmission parameter information includes information such as the transmission mode, carrier modulation scheme, coding rate, layer information, and interleave length.

  Further, the demodulating means 106a extracts pilot signals that are arranged in the OFDM signal at regular intervals in the frequency and time directions. The demodulator 106a compares the extracted pilot signal with a reference value (known amplitude and phase), and calculates the channel characteristic (degree of amplitude and phase deviation) of the carrier in which the pilot signal exists from the change in amplitude and phase. To do. Next, the channel characteristics of the carrier with the pilot signal calculated by the pilot extraction means are interpolated in the time direction and the frequency direction, and the estimated values of the channel characteristics of all OFDM carriers are calculated and output. Interpolation is performed by using the transmission path characteristics of pilot carriers so as to increase or decrease sequentially according to the number of data carriers existing between pilot carriers, or by unifying them with an average value. Then, the signal obtained from the FFT operation means 105 a is divided by the estimated value of the transmission path characteristic, and a complex signal based on the division result is calculated and output to the combining means 108.

  Further, the demodulating means 106a outputs power information indicating the power amount of each OFDM carrier calculated using the channel characteristics estimated from the pilot signal and amplitude information indicating the amplitude amount of each OFDM carrier to the synthesizing means 108a.

  Regarding the configuration of 101b to 106b, the individual description is the same as that of 101a to 106a described above, and is omitted.

  The transmission parameter comparison unit 107 determines whether or not the partial reception segment (one segment part) of the channel a and the channel b can be replaced.

  FIG. 2 is a flowchart showing a procedure when the transmission parameter comparison means 107 determines whether or not the partial reception segments of the channel a and the channel b can be replaced. FIG. 3 is a conceptual diagram showing replacement of partial reception segments of channel a and channel b.

  The transmission parameter comparison unit 107 inputs a segment replacement command from a replacement instruction unit (not shown). This replacement instruction may be issued based on a sub-screen display instruction by the user. The transmission parameter comparison means 107 also obtains information on the mode and guard ratio of channel a and channel b from the demodulation means 106a and 106b. Further, various parameter information of the OFDM transmission signal demodulated from the TMCC signals of channel a and channel b is also obtained from the demodulation means 106a and 106b.

  The transmission parameter comparison means 107 that has obtained the information determines whether or not the segment can be replaced.

  When the antenna units 101a and 101b receive different channels as in the first embodiment (FIG. 2, step S001), the transmission parameter comparison unit 107 has the same channel a and channel b signal modes and guard ratios. A comparison is made (step S002). Here, when it is determined that one or both of the mode and / or guard ratio of the signals of channel a and channel b are different (step S003), the partial reception segment portion cannot be replaced (step S006). On the other hand, when it is determined that the channel a and channel b signal modes and guard ratios are the same (step S003), the transmission parameter comparison means 107 then receives both the channel a and channel b signals partially. It is determined whether or not there is a segment (step S004). This determination is made by referring to the partial reception flag of the TMCC signal input from the demodulation means 106a and 106b. If it is determined that either one or both of channel a and channel b do not have a partial reception segment, the partial reception segment is not replaced (step S006). On the other hand, if both of the above two conditions are met, the transmission parameter comparison means 107 determines that the partial reception segment can be replaced.

  In the above procedure, when the transmission parameter comparison unit 107 determines that the partial reception segment can be replaced, the transmission parameter comparison unit 107 outputs a determination result as to whether the segment can be replaced to the combining unit 108. Also, the transmission parameter comparison unit 107 replaces the transmission parameter information of the partial reception segment to be replaced among the transmission parameter information of the channels a and b obtained from the demodulation units 106a and 106b.

  For example, when channel a and channel b are broadcasting an HDTV1 program in a 12 segment portion, and channel a is displayed as a sub-screen with respect to the screen displaying channel b, transmission parameters relating to the broadcasting of the 12 segment portion of channel b Information and transmission parameter information related to broadcasting of one segment part of channel a are selected, and the regenerated transmission parameter information is sent to the subsequent block (deinterleaving means 109, demapping means 110, bit deinterleaving means 111, error correction means 112). Output.

  When the transmission parameter comparison unit 107 determines that the partial reception segment cannot be replaced, the determination result may be transmitted to a screen display unit (not shown) to notify the user that the sub screen cannot be displayed.

  The synthesizing unit 108 selects the segment of channel a and channel b based on the determination result input from the transmission parameter comparison unit 107. For example, when a determination result indicating that the partial reception segment can be replaced is input from the transmission parameter comparison unit 107, the partial reception segment of channel a and the 12 segment part of channel b are selected as shown in FIG. Specifically, the complex signal of one segment of the selected channel a is temporarily stored in the buffer, and the timing is adjusted so that the head position of the OFDM frame of the one segment portion matches the signal of 12 segments and output. In this case, the start position of the OFDM frame can be known from a pulse signal indicating the start of the frame.

  The synthesizing unit 108 outputs the selected complex signal to the deinterleaving unit 109. Further, the synthesizing unit outputs the power information or the amplitude information obtained from the demodulating units 106a and 106b to the deinterleaving unit 109 as reliability information.

  The deinterleaving means 109 rearranges the complex signals of the received signal points after selection obtained from the synthesizing means 108 in the frequency and time directions. The rearrangement method is defined in advance, and the rearrangement performed on the transmission side is restored.

  The demapping means 110 restores the bit data possessed by the signal based on the received signal point information obtained from the deinterleave means 109. The bit data is restored on the assumption that the code string assigned to the mapping point closest to the received signal point is the transmission code string. For example, when the received signal is carrier-modulated by 16QAM modulation, bit data is restored according to the rules shown in FIG. At this time, for each bit, the shortest distance between the mapping point where the transmission code point is 0 with respect to the reception signal point and the mapping point where the transmission code point is 1 is calculated, and the value obtained according to the distance is represented by the likelihood ( (0-likeness, 1-likeness) is transmitted to the error correction means in the subsequent stage (referred to as soft decision).

  When calculating the likelihood, the likelihood is corrected using the reliability information obtained from the synthesizing unit 108 via the deinterleaving unit 109. When the reliability information is a low value, the likelihood is corrected to 0 (the likelihood of 0 is equal to 1), and when the reliability information is a high value, the calculated likelihood is output without being corrected. Alternatively, the reliability value, which is the carrier power information or amplitude information obtained from the combining means 108, is multiplied by the previously obtained likelihood and output.

  As described above, the demapping unit 110 calculates and outputs the bit data string obtained from the information on the reception point obtained from the combining unit 108 and the likelihood for each bit.

  Next, the bit deinterleaving means rearranges the outputs of the demapping means 110. The rearrangement method is defined in advance, and the rearrangement performed on the transmission side is restored.

  The error correction unit 112 performs error correction using the bit data string obtained from the bit deinterleave unit 111 and the likelihood information of each bit data. At this time, an error correction method called Viterbi decoding is often used, and a Reed-Solomon correction code is often combined. However, the present invention is not limited to this, and any error correction using the above-described likelihood may be used. Such a method may be used.

  Thereby, it is possible to obtain a broadcast signal obtained by replacing only one segment portion among broadcast signals received in terrestrial digital broadcasting. In this way, a sub-screen display can be performed on a video display unit (not shown) using a broadcast signal in which only one segment portion is replaced. When displaying the sub-screen, the video display unit extracts one segment from the broadcast signal, and displays the sub-screen at any location specified by the user among the display units displaying the remaining 12-segment screen. Just do it. When one segment portion is data broadcasting, character information can be displayed at the lower end portion of the display screen.

  As described above, according to the receiving apparatus of the present invention, one segment broadcast of another channel can be displayed on a small screen while a program for fixed reception of a certain channel is being auditioned. In addition, since such two-screen display can be performed based on the decoding process of one synthesized broadcast signal, the decoding process of a plurality of video signals required by the conventional two-screen display function is not necessary, and the receiving device It is possible to reduce the number of parts and power consumption.

(Embodiment 2)
In the second embodiment, partial segment replacement according to the present invention is incorporated into a diversity receiver having a plurality of branches.

  FIG. 5 is a block diagram showing another example of the present invention.

  In FIG. 5, 101n to 106n correspond to 101a to 106a in the first embodiment.

  In the second embodiment, the user gives an instruction to a replacement instruction unit (not shown) as to which channel the main screen in the screen display is to be selected and which channel is to be displayed in the sub-screen. In this case, which channel each branch (101a to 106a, 101b to 106b...) Receives is based on a command from the replacement instruction unit. The tuner means 102a to 102n extract a signal in a specific frequency band from the signals obtained from the antenna means 101a to 101n in accordance with a command from the replacement instruction unit, and convert the signal into a baseband or a constant frequency band signal.

  Which branch receives which channel is determined based on a command from the replacement instructing unit, but how many branches receive the channel can be arbitrarily set. For example, in the case of a 4-branch diversity receiver, it can be determined that the branches a and b receive the channel a and the branches c and d receive the channel b. In this case, the broadcast signals from the branches a and b are diversity combined, and the broadcast signals from the branches c and d are diversity combined. Then, the segments of channel a and channel b may be synthesized. Thereby, it is possible to realize a good reception state even in the partial reception segment. On the other hand, when the diversity receiver is composed of three or more branches, the one-segment reception is usually more resistant to errors than the fixed reception broadcasting, so one branch is used for one-segment reception. In use, the remaining branches may receive 12 segments. In this case, the 12 segment portion performs a combining operation, and the transmission parameter information is selected for only one segment portion. Thereby, it is possible to perform sub-screen display while maintaining a good reception state for the main screen in screen display. When the data broadcast is included in one segment, the data broadcast may be stored in a storage medium such as a memory or a hard disk so that the user can select it later and display it on the screen.

  The transmission parameter comparison unit 107 and the synthesis unit 108 also perform respective processes based on a sub-screen display command from the replacement instruction unit. In other words, the transmission parameter comparison unit 107 determines whether or not the partial reception segment of the channel a or the channel b that becomes the sub screen display can be replaced based on the sub screen display command from the replacement instruction unit. The synthesizing unit 108 selects a segment of channel a or channel b based on a sub-screen display command from the replacement instruction unit. For example, when there is a command to display the sub screen of channel a from the replacement instruction unit, the transmission parameter comparison means 107 transmits transmission parameter information related to the broadcast of the 12 segment portion of channel b and transmission parameter information related to the broadcast of the 1 segment portion of channel a And the regenerated transmission parameter information is output to the subsequent block (deinterleaving means 109, demapping means 110, bit deinterleaving means 111, error correction means 112). The synthesizing unit 108 selects a 12-segment complex signal of channel b and a partial reception segment of channel a, adjusts the timing of both, and outputs the result to the deinterleaving unit 109.

  In the second embodiment, the synthesizing unit 108 performs not only the segment selection described in the first embodiment but also diversity combining of the complex signals output from the plurality of demodulating units 106. That is, the synthesizing unit 108 obtains a complex signal, power information, and amplitude information from the demodulating units 106a to 106n. Then, the complex signals obtained from the demodulation means 106a to 106n are synthesized. At the time of synthesis, weighting processing is performed based on the power amount or amplitude amount α, β, γ,... Of the carrier to which the received signal calculated by the demodulation means 106a to 106n is transmitted, and the signals are added. The electric power amount or the amplitude amount α, β, γ... May be a quantized value.

  Combining means 108 outputs complex information and reliability information of the received signal points after combining to deinterleaving means 109 at the subsequent stage.

  Since the subsequent operations are the same as those in the first embodiment, the description thereof is omitted.

  As described above, according to the receiving apparatus of the second embodiment of the present invention, even in a diversity receiving apparatus having a plurality of branches, it is possible to replace a partial receiving segment and realize a sub screen display and a data broadcast screen display. When the diversity reception apparatus is in a good reception condition and it is not always necessary to use a plurality of branches, it is possible to increase functions such as a small screen display by using “empty tuner + demodulation unit”. In addition, when the diversity reception device is in good reception, the channel selection channels of one branch are automatically switched sequentially, and the data broadcasts included in the partial reception segment portions of a plurality of channels are stored in a storage medium such as a memory or a hard disk. It is also possible to store it so that the user can select it later and display it on the screen.

  According to the receiving apparatus of the present invention, it is possible to display a one-segment broadcast of another channel on a small screen while listening to a program for fixed reception of a certain channel. It can be used industrially as a receiving apparatus that meets such user's needs.

The block diagram which shows the structure of the receiver in Embodiment 1 of this invention. The flowchart explaining operation | movement of the transmission parameter comparison means in Embodiment 1 of this invention. The figure explaining replacement of the partial reception segment in Embodiment 1 of this invention The figure which showed the restoration method of the bit data in Embodiment 1 of this invention The block diagram which shows the structure of the receiver in Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Antenna means 102 Tuner means 103 A / D conversion means 104 Quadrature detection means 105 FFT operation means 106 Demodulation means 107 Transmission parameter comparison means 108 Synthesis means 109 Deinterleave means 110 Demap means 111 Bit deinterleave means 112 Error correction means

Claims (8)

A replacement instruction means for the user to specify a sub-screen display channel;
First tuner means for receiving a signal modulated by a digital multi-level modulation method from an antenna and extracting a signal in a frequency band of a first channel that is a channel designated by the replacement instruction means ;
Second tuner means for receiving a signal modulated by a digital multi-level modulation method from an antenna and extracting a signal in a frequency band of a second channel which is another main screen display channel ;
Complex information indicating a signal point of a signal in the frequency band of the first channel, which is an output of the first tuner means, is output, and information necessary for demodulation is described from the signal in the frequency band of the first channel First demodulation means for extracting and outputting transmission parameters;
Complex information indicating the signal point of the frequency band signal of the second channel, which is the output of the second tuner means, is output, and information necessary for demodulation is described from the signal of the frequency band of the second channel Second demodulation means for extracting and outputting transmission parameters;
Based on the output of the first demodulating means and the output of the second demodulating means, the first channel and the second channel are different, and the signal modes of the first channel and the second channel are different. and if the a guard ratio of the same first channel signal of the second channel has a portion received segment together, said first portion received segments according to the channel complex information and the second channel A replaceable determination result that allows replacement of complex information of the partial reception segment is output, and the transmission parameter of the partial reception segment related to the first channel is changed to the transmission parameter of the partial reception segment related to the second channel. A transmission parameter comparison means to be replaced;
Combining means for replacing the complex information of the partial reception segment related to the first channel and the complex information of the partial reception segment related to the second channel based on the replaceable determination result which is the output of the transmission parameter comparison means When,
Demapping means for performing bit data restoration of complex information input from the combining means according to the transmission parameters output by the transmission parameter comparing means;
A receiving apparatus. A replacement instruction means for the user to specify a sub-screen display channel;
A signal modulated by the digital multilevel modulation method is received from an n-th (n is a positive integer) antenna, and a signal in the frequency band of the first channel, which is a channel designated by the replacement instruction means, is extracted. The complex information indicating the signal point of the signal in the frequency band of the first channel, which is the output of the tuner means, and the output of the n-th tuner means is output and necessary for demodulation from the signal in the frequency band of the first channel A first branch group, which is a group of reception systems, comprising: n-th demodulation means for extracting and outputting transmission parameters describing various information;
A signal modulated by a digital multilevel modulation method is received from an m-th antenna (m is a positive integer different from n), and a signal in the frequency band of the second channel, which is another main screen display channel, is extracted. The complex information indicating the signal point of the signal of the frequency band of the second channel which is the output of the mth tuner means and the mth tuner means is output and demodulated from the signal of the frequency band of the second channel A second branch group, which is a group of reception systems, comprising: m-th demodulation means for extracting and outputting transmission parameters describing information necessary for
Based on the output of the first branch group and the output of the second branch group, the first channel and the second channel are different, and the signal modes of the first channel and the second channel are different. and if the a guard ratio of the same first channel signal of the second channel has a portion received segment together, said first portion received segments according to the channel complex information and the second channel A replaceable determination result that enables replacement of complex information of the partial reception segment is output, and the transmission parameter of the partial reception segment related to the first channel is changed to the transmission parameter of the partial reception segment related to the second channel. A transmission parameter comparison means to be replaced;
Diversity combining of complex information that is the output of the first branch group is performed, diversity combining of complex information that is the output of the second branch group is performed, and output of the transmission parameter comparing means is performed on the complex information after diversity combining. a synthesizing means for performing the replacement of the complex information of the partial receiving segment with complex information according to the second channel of the partial reception segment of the first channel based on replaceable determination result is,
Demapping means for performing bit data restoration of complex information input from the combining means according to the transmission parameters output by the transmission parameter comparing means;
A receiving apparatus. The synthesizing unit temporarily stores the complex information of the partial reception segment related to the first channel, which is the channel designated by the user, in the buffer unit, and sets the stored start position of the partial reception segment as the other channel. The receiving apparatus according to claim 1, wherein complex information is replaced by outputting in accordance with a head position of a segment other than the partial receiving segment in the two channels. The receiving apparatus according to claim 2, wherein the constituent elements of the first branch group are one receiving system, and the constituent elements of the second branch group are a plurality of receiving systems. A program for causing a computer to function as the receiving device according to claim 1. A program for causing a computer to function as the receiving device according to claim 2. A computer-readable recording medium on which the program according to claim 5 is recorded. A computer-readable recording medium on which the program according to claim 6 is recorded.

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