JP5085696B2 - Linked transmission system and linked transmission method - Google Patents

Description

  Embodiments described herein relate generally to a concatenated transmission system and a concatenated transmission method for concatenating a plurality of broadcast TSs and modulating and transmitting the signals using an OFDM (Orthogonal Frequency Division Multiplexing) method.

  ISDB-Tmm and ISDB-Tsb systems have been proposed as systems that satisfy the technical requirements of the “multimedia broadcasting for portable terminals” scheduled for 2011 and thereafter. Both systems are based on ISDB-T, and are characterized by the 13-segment transmission wave of the terrestrial digital television broadcast transmission system standard (ARIB STD-B31) and the terrestrial digital audio broadcast transmission system standard (ARIB). STD-B29) 1-segment or 3-segment transmission waves can be used as unit transmission waves, and these can be transmitted in a line on the frequency axis without a guard band, and effective use of frequencies can be achieved. As a method for realizing concatenated transmission, it is conceivable to perform an IFFT process on the concatenated signals collectively to generate an OFDM signal.

  On the other hand, from the viewpoint of reduction of energy used, economy, etc., it is desirable to stop transmission when broadcasting is stopped, but in the case of concatenated transmission, since adjacent unit transmission waves are shared, It is difficult to stop in units of connected transmission waves. Therefore, when broadcasting a certain unit transmission wave, even if there is no information to be broadcast, dummy data is generated instead (in many cases, the dummy data is MPEG2-NULL Packet), and the transmission path is encoded. Send continuously. At this time, it is known that when there are a plurality of unit suspension waves for broadcasting suspension, the probability of generation of a signal having a higher peak amplitude is higher than that of a normal broadcasting wave, and this affects the transmitting equipment.

  This is because the NULL packet inserted instead of the broadcast information described above takes the same data value in each unit transmission wave. In a unit transmission wave unit, energy diffusion processing is performed in order to maintain sufficient randomness of data no matter what data is input. However, when the unit transmission waves that are the unit of connection have the same transmission parameters, the same signal processing is performed, so when the same signal is input, it becomes the same output signal and is added in the same phase, so the peak amplitude increases. End up.

JP 2009-16923 A

  The objective of this embodiment is to provide the connection transmission system and connection transmission method which can suppress the increase in the peak amplitude at the time of connection transmission.

  The concatenated transmission system according to the present embodiment includes a plurality of multiple frame generation units that generate multiple frames of a plurality of unit transmission waves of at least one segment, and at least TS packets so that the correlation between the unit transmission waves is small. A plurality of dummy data generators for generating dummy data constituting a part, and data for selecting the data of the multiplexed frame for normal operation and for selecting dummy data of the TS packet for operation suspension for each unit transmission wave A selection unit; and a plurality of OFDM frame generation units that generate a plurality of OFDM (Orthogonal Frequency Division Multiplexing) frames based on the data selected by the data selection unit.

  In addition, the concatenated transmission method according to the present embodiment generates multiple frames of a plurality of system unit transmission waves composed of at least one segment, and configures at least a part of the TS packet so that the correlation between the unit transmission waves is reduced. Dummy data is generated, and for each unit transmission wave, the data of the multiplexed frame is selected during normal operation, the dummy data of the TS packet is selected during operation suspension, and a plurality of systems are selected based on the selected data. An OFDM (Orthogonal Frequency Division Multiplexing) frame is generated.

The block diagram which shows the structural example of the connection transmission system which concerns on 1st Embodiment. The figure which shows the structure of the dummy data insertion part which concerns on 1st Embodiment. The block diagram which shows the structural example of the connection transmission system which concerns on 2nd Embodiment. The figure which shows the structure of the dummy data insertion part which concerns on 2nd Embodiment. The figure which shows the structure of the dummy data insertion part which concerns on the modification 1. As shown in FIG. The figure which shows the structure of the dummy data insertion part which concerns on the modification 1. As shown in FIG. The figure which shows the structure of the dummy data insertion part which concerns on the modification 2. As shown in FIG. The figure which shows the structure of the dummy data insertion part which concerns on the modification 2. As shown in FIG. The figure which shows the structure of the dummy data insertion part which concerns on the modification 2. As shown in FIG. The figure which shows the structure of the dummy data insertion part which concerns on the modification 2. As shown in FIG.

  Hereinafter, the coupled transmission system and the coupled transmission method according to the present embodiment will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration example of a linked transmission system according to the first embodiment. FIG. 1 shows an example in the case of N connected transmissions.

  This concatenated transmission system includes multiple frame generators 11-1 to 11-N, dummy data inserters 12-1 to 12-N, a concatenated multiplexer 13, a transmission path 14, a concatenator 15 and an OFDM. Frame generation units 16-1 to 16-N, a batch IFFT processing unit 17, and a guard interval adding unit 18 are provided.

  First, the multiplex frame generation units 11-1 to 11-N generate a broadcast TS composed of multiplex frames for each of a plurality of system unit transmission waves including at least one segment. The output is input to the concatenated multiplexing unit 13 via dummy data insertion units 12-1 to 12-N, which will be described later, and has a multiplexed frame structure of concatenated transmission waves. This signal is input to the connection / separation unit 15 through the transmission line 14 and is separated for each multiplex frame structure of the original unit transmission wave to become a broadcast TS. The broadcast TS of the separated unit transmission waves is subjected to transmission path encoding processing by the OFDM frame generation units 16-1 to 16-N, respectively, and has an OFDM frame configuration for each unit transmission wave. The collective IFFT processing unit 17 performs signal processing necessary for concatenated transmission, and collectively performs an IFFT (inverse Fourier transform) process on the signals constituting the OFDM frame of each unit transmission wave. The guard interval adding unit 110 adds a guard interval to the signal and generates a baseband signal of a prescribed signal.

  In the configuration of FIG. 1, the dummy data insertion units 12-1 to 12-N may be arranged between the connection / separation unit 15 and the OFDM frame generation units 16-1 to 16-N. Further, in the actual configuration, a case where the block 102 in FIG. 1 is omitted and a plurality of broadcast TSs of each unit transmission wave are input as they are to the OFDM frame generation units 16-1 to 16-N is assumed. Further, in an actual apparatus, a case where the multiplexed frame generating units 11-1 to 11-N and the concatenated multiplexing unit 13 are realized in the same apparatus (configuration 101 in FIG. 1), OFDM frame generating units 16-1 to 16-1 A case (configuration 103 in FIG. 1) in which the 16-N and the connecting / separating unit 15 are realized in the same apparatus is also assumed.

  Next, the operation of the dummy data insertion unit will be described with reference to FIG. FIG. 2 is a diagram illustrating a configuration of the dummy data insertion unit according to the first embodiment. As an example of the dummy data, a NULL packet is used.

  The dummy data insertion unit 12-1 includes a dummy data generation unit 21-1 and a data selection unit 22-1. The multiplex frame TS of the unit transmission wave 1 is input to the port P1 of the data selection unit 22-1. The dummy data generation unit 21-1 generates a signal indicating a payload of a NULL packet having arbitrary fixed value (AA) data, and inputs the signal to the port P2 of the data selection unit 22-1. When the data selection unit 22-1 indicates that both the signal indicating the payload of the NULL packet and the control signal indicating that the unit transmission wave 1 is not in the normal operation state are valid, the data selection unit 22-1 uses the port P2 Is selected and a fixed value AA is output. In other cases, the input of the port P1 is output.

  The operations of the dummy data generating units 21-1 to 21-N and the data selecting units 22-1 to 22-N are basically the same, but the TS of the multiplexed frame of the input unit transmission wave is different. The control signal indicating that the unit transmission wave is not in the normal operation state is different. Among these, the fixed values generated by the dummy data generating units 21-1 to 21-N are set to different values (AA, BB,..., XX in the case of FIG. 2), so that dummy data is transmitted between unit transmission waves. The correlation is reduced.

  Therefore, according to the first embodiment, even when there are a plurality of broadcast-suspended unit transmission waves, since the correlation of dummy data between the unit transmission waves is reduced, it is possible to suppress an increase in peak amplitude at the time of concatenated transmission. It becomes.

(Second Embodiment)
In the second embodiment, dummy data is inserted into a signal after concatenation multiplexing. FIG. 3 is a block diagram illustrating a configuration example of the linked transmission system according to the second embodiment. 3 is different from FIG. 1 in that the dummy data insertion unit 19 is arranged in the subsequent stage of the connection multiplexing unit 13. Since other configurations are the same as those in FIG. 1, the same components are denoted by the same reference numerals, and detailed description thereof is omitted. In the configuration of FIG. 3, the dummy data insertion unit 19 can be disposed between the transmission line 14 and the connection / separation unit 15.

  FIG. 4 shows the configuration of the dummy data insertion unit 19. The dummy data insertion unit 19 includes dummy data generation units 31-1 to 31 -N and a data selection unit 32. A signal after concatenation multiplexing is input to the port P1 of the data selection unit 32. The dummy data generation units 31-1 to 31-N generate signals indicating the payloads of NULL packets having data of arbitrary fixed values (AA, BB,..., XX) different from each other, and the data selection unit 22-1. Input to ports P2-1 to P2-N, respectively.

  The data selection unit 32 selects and fixes the input of the port P2-1 when the signal indicating the payload of the NULL packet and the control signal indicating that the unit transmission wave 1 is not in the normal operation state are both valid. The value AA is output. In addition, when the signal indicating the payload of the NULL packet and the control signal indicating that the unit transmission wave 2 is not in the normal operation state are both valid, the data selection unit 32 selects the input of the port P2-2. A fixed value BB is output. Thereafter, the same operation is performed up to the unit transmission wave N. In other cases, the input of the port P1 is selected and output.

  Thus, even when configured as in the second embodiment, as in the first embodiment, even when there are a plurality of broadcast pause unit transmission waves, the correlation of dummy data between the unit transmission waves becomes small. It is possible to suppress an increase in peak amplitude during concatenated transmission.

(Modification 1)
5 and 6 show the configuration of the dummy data insertion unit according to the first modification. FIGS. 5 and 6 show cases where the payload data of the NULL packet is PRBS (Pseudo Random Binary Bit Sequence) in each of FIGS. Since it is the same except that the content of the payload of the NULL packet is different, detailed description is omitted.

  The dummy data generating units 21A-1 to 21A-N and 31A-1 to 31A-N generate different PRBS patterns (AA, BB,..., XX) between unit transmission waves. For example, the following method can be considered. In the first method, the generation formula for generating the PRBS is different between unit transmission waves. In the second method, the initial value of the generation formula for generating PRBS is different between unit transmission waves. In this embodiment, the method is not specified.

(Modification 2)
7, 8, 9, and 10 show the configuration of the dummy data insertion unit according to the second modification. 7, 8, 9, and 10, in each of FIGS. 2, 4, 5, and 6, since the selection range is the payload portion of the NULL packet, the header of the NULL packet is usually a fixed value, This is an example in which the entire NULL packet (header + payload) is selected. Since the operation / action is the same except for the difference in the selection range described above, a detailed description thereof will be omitted.

  7 and 8, dummy data generators 21B-1 to 21B-N, 31B-1 to 31B-N are all NULL packets (headers) having data of arbitrary fixed values (AA, BB,..., XX). + Payload) is generated. The data selection units 22-1 to 21-N and 32 indicate that both the signal indicating the entire NULL packet (header + payload) and the control signal indicating that the unit transmission wave is not in the normal operation state are valid. At times, the inputs of the ports P2, P2-1 to P2-N are selected and fixed values (AA, BB,..., XX) are output. In other cases, the input of the port P1 is output.

  9 and 10, dummy data generators 21C-1 to 21C-N and 31C-1 to 31C-N are NULL packets having different PRBS patterns (AA, BB,..., XX) between unit transmission waves. A signal indicating the whole (header + payload) is generated. The data selection units 22-1 to 21-N and 32 indicate that both the signal indicating the entire NULL packet (header + payload) and the control signal indicating that the unit transmission wave is not in the normal operation state are valid. At times, the inputs of the ports P2, P2-1 to P2-N are selected and a PRBS pattern (AA, BB,..., XX) is output. In other cases, the input of the port P1 is output.

  As described above, in the above embodiment, the value of the payload portion of the NULL packet inserted as dummy data at the time of broadcasting suspension is set to a different value for each unit transmission wave. By doing in this way, the peak power to average power ratio (PAPR) of the output signal at the time of broadcasting suspension in the concatenated transmission is increased as compared with the case where the unit transmission wave is transmitted alone. It is possible to suppress and operate in a transmission system having the same dynamic range as the unit transmission wave.

  In addition to the above-described embodiment, for example, the following two methods are conceivable as measures for suppressing an increase in peak amplitude at the time of concatenated transmission. In the first method, the transmission parameter of the unit transmission wave to be paused is set to be different from other unit transmission waves. In the second method, TS packets that do not become the same packet between unit transmission waves and cannot be received are generated for each unit transmission wave (for example, PSI information is discarded from data similar to a program that is actually broadcast). So that it cannot be received.)

  Since the first and second methods directly affect the parameter control and SI control in the operation system, it is necessary to verify including the influence on the unit segments other than the unit segment to be paused. In the first method, transmission parameters are always changed before and after the start of operation, which causes a problem in actual operation. In the second method, it is necessary to operate an apparatus that is an actual information source even when the apparatus is not in operation.

  On the other hand, since this embodiment does not cause a problem in actual operation, it is effective for suppressing an increase in peak amplitude during concatenated transmission.

  In addition, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  11-1 to 11-N: Multiple frame generation unit, 12-1 to 12-N: Dummy data insertion unit, 13: Connection multiplexing unit, 14: Transmission path, 15 ... Connection separation unit, 16-1 to 16-N ... OFDM frame generation unit, 17 ... Batch IFFT processing unit, 18 ... Guard interval addition unit, 21-1 to 21-N ... Dummy data generation unit, 22-1 to 22-N ... Data selection unit, 19 ... Dummy data insertion , 31-1 to 31 -N ... dummy data generation unit, 32 ... data selection unit.

Claims (6)

A plurality of multiple frame generation units for generating multiple frames of a plurality of unit transmission waves of at least one segment;
A plurality of dummy data generators for generating dummy data comprising at least a part of TS packets with different values between the unit transmission waves so as to reduce the correlation between the unit transmission waves ;
For each unit transmission wave, a data selection unit that selects the data of the multiplex frame during normal operation and the dummy data of the TS packet during operation suspension;
A concatenated transmission system comprising: a plurality of OFDM frame generation units that generate a plurality of OFDM (Orthogonal Frequency Division Multiplexing) frames based on the data selected by the data selection unit.   The concatenated transmission system according to claim 1, wherein the value of the dummy data is a fixed value different between the unit transmission waves.   2. The concatenated transmission system according to claim 1, wherein the value of the dummy data is PRBS (Pseudo Random Binary Bit Sequence) generated by different generation methods between the unit transmission waves. Generate multiple frames of multiple unit transmission waves consisting of at least one segment,
Generating dummy data comprising at least part of the TS packet with different values between the unit transmission waves so that the correlation between the unit transmission waves is small;
For each unit transmission wave, select the data of the multiple frame during normal operation, select dummy data of the TS packet during operation suspension,
A concatenated transmission method characterized by generating a plurality of OFDM (Orthogonal Frequency Division Multiplexing) frames based on the selected data.   5. The concatenated transmission method according to claim 4, wherein the value of the dummy data is a fixed value different between the unit transmission waves.   5. The concatenated transmission method according to claim 4, wherein the value of the dummy data is a PRB (Pseudo Random Binary Bit Sequence) generated by different generation methods between the unit transmission waves.

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