CN1251498C

CN1251498C - Digital broadcasting system transmitter and method

Info

Publication number: CN1251498C
Application number: CNB031234801A
Authority: CN
Inventors: 金纪甫
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2002-10-19
Filing date: 2003-05-09
Publication date: 2006-04-12
Anticipated expiration: 2023-05-09
Also published as: CN1491035A; CN1801950A; CN1245835C; KR100918819B1; KR20040035296A; CN1491038A

Abstract

A transmission device of a digital broadcasting system having an inner interleaver with an improved structure is provided to perform a bit interleaving process by a convolution interleaving method, and to carry out a symbol interleaving process by using an optional random lookup table, thereby improving randomized properties of an inner interleaver. The first and second RS encoders(12,22) RS(Read-Solomon)-encode the first and second TSs(Transport Streams). The first and second outer interleavers(14,24) re-array data encoded in the first and second RS encoders(12,22), respectively. The first and second convolution encoders(16,26) convolution-encode the re-arrayed data, respectively. An inner interleaver(30) consists of a bit interleaver(31) and a symbol interleaver(33). The bit interleaver(31) re-arrays the encoded data in bit unit by the convolution encoders(16,26). The symbol interleaver(33) re-arrays the data in symbol unit by a predetermined interleaving address of a lookup table. A modulator portion(50) digitally modulates the re-arrayed data, and transmits the modulated data.

Description

Digital broadcasting system transmitter and method

Technical field

The present invention relates to a kind of dispensing device and method of digit broadcasting system, more specifically, relate to the digit broadcasting system and the method for the randomness that can improve interleaver.

Background technology

Compare with analog broadcasting, digital encoding system is used in digital broadcasting, has the advantage of system synthesis and interactive operation.Therefore, by means of computer and network, the requirement that so-called medium are concentrated the center has been satisfied in digital broadcasting.In addition, the also more unidirectional analog broadcasting of the interactive features of digital broadcasting has obtained great progress.

In order to guarantee the comprehensive and interactive operation of digital broadcasting, at first, need the introducing standard.At present, the sending method of the Digital Terrestrial Television Broadcast of recommendation has the 8-VSB (residual sideband) of the U.S. and the COFDM (OFDM of coding) in Europe.

Because digital broadcasting needs the compressed signal source sending mass data, so a small amount of mistake that occurs in the passage is appreciable to the influence of whole system.Therefore, must reduce the mistake that occurs in the passage.In order to reduce errors, can increase transmitted power to improve signal to noise ratio (snr).But this can bring the cost that causes such as the height output owing to big transmitted power and dispensing device to increase and interchannel interference.In order to alleviate these problems, digit broadcasting system uses error correcting code, can not increase transmitted power mistake is corrected.Error correcting code can not increase transmitted power and correct the mistake that occurs in the passage, reduces the possibility that goes wrong in the receiver.

Error correcting code is divided into automatic repeat request (ARQ) and forward error correction (FEC) dual mode substantially.According to ARQ, if detect mistake in receiver, receiver sends the request signal of these data of request repeat to transmitter.Thereby transmitter is retransmitted this data.Because ARQ need allow the backward channel of receiver to transmitter transmission re-send request may signal, so this method is not suitable for using in digital broadcasting.Simultaneously based on FEC, signal is to send with the diacritic that is attached to this signal, thus the mistake that receiver occurs in can sense channel, and correct it with algebraic method.

FEC is divided into block code and convolutional code substantially.Block code carries out Code And Decode by block unit to information, and it comprises Hamming code, BCH code and RS (Rui De-Saloman) sign indicating number.In these sign indicating numbers, the RS sign indicating number is good on range performance, comprises effective Code And Decode algorithm, therefore is widely used in digit broadcasting system.The RS sign indicating number is very outstanding in correcting burst error, because it detects and correct mistake by block unit.

Simultaneously, for convolution code, its carry-out bit is subjected to over the influence of input position and current input position, and it is being effective aspect correction random error.Viterbi decoder is generally used for decode convolutional codes.

Usually, the interleaver according to European DVB-T standard has: position interleaver and symbol interleaver.The position interleaver is used for step-by-step unit's interleaving data; And symbol interleaver is used for by the symbolic unit data that the OFDM subcarrier carries that interweave.For example, interweave by the OFDM symbolic unit, corresponding to the quantity of the valid data symbol of 2K FFT pattern with the symbol interleaver of 2K FFT pattern.

The interleaver of DVB-T, interleaver and the symbol interleaver of ascending the throne produces interleaving address according to the structure interlacing rule.Structure interweaves and refers to that promptly the ad hoc rules according to mainly being Arithmetic Formula produces interleaving address.

The advantage that structure interweaves is to have simplified the design of transmitter and receiver, rather than the improvement on performance at random.

Summary of the invention

Exploitation of the present invention is in order to solve the aforementioned problems in the prior.Therefore, an object of the present invention is to provide a kind of dispensing device and method thereof with digit broadcasting system of the interleaver that randomness improves.

Above-mentioned purpose is to realize by the dispensing device that a kind of digit broadcasting system is provided, and described dispensing device comprises: first and second outer encoders, respectively first and second transmission (TS) streams of input are carried out coding; First and second external interleavers, execution interweaves to the first and second outer encoder coded datas respectively; First and second inner encoders are carried out coding to the data that first and second external interleavers interweave respectively; Interleaver, comprise: the position interleaver, be used for the first and second inner encoder coded data execute bits are interweaved, and symbol interleaver, the data that the predetermined interleaving address contraposition interleaver that is used for using question blank (LUT) to provide carries out after the position interweaves are carried out symbol interleaving; And modulating unit, the data that are used for that interleaver is interweaved are carried out digital modulation and are sent this data.

Symbol interleaver comprises: first and second memories are used for reading and write the data that interweaved by the position interleaver by symbolic unit; Address generator is used for producing interleaving address based on LUT; And controller, be used for the control address generator, make reading of first and second memories carry out according to interleaving address with write operation.

Modulating unit uses OFDM to carry out digital modulation.Modulating unit comprises: mapping/OFDM modulator block is used for according to mapping method the data that interleaver interweaves being shone upon, and carries out the OFDM modulation; Pilot tone/system information is inserted piece, is provided for the pilot signal of signal Synchronization and signal estimation and the information of relevant sending mode to mapping/OFDM modulator block; Piece is inserted in protection (GI) at interval, is used for GI is inserted into from the signal of mapping/OFDM modulator block output; Numeral is used for the signal that has inserted GI is carried out the D/A conversion to simulation (D/A) conversion block; And radio frequency (RF) piece, be used for the conversion of signals through the D/A conversion is become high-frequency signal and sends this signal.

Dispensing device also comprises: first and second scramblers are used for respectively the first and second TS streams being carried out randomization, so that the first and second TS streams after the randomization are provided to first and second outer encoders.

First and second outer encoders are to use Rui De-Saloman () encoder of Rui De-Solomon code.

Dispensing device also comprises second interleaver.Second interleaver comprises: second interleaver is used for the second inner encoder coded data execute bit is interweaved; And second symbol interleaver, the predetermined interleaving address that is used for using question blank (LUT) to provide carries out symbol interleaving to the data that second interleaver carries out after the position interweaves; Wherein said position interleaver is used for the first inner encoder coded data execute bit is interweaved; And described symbol interleaver is used to use interleaving address that the data that institute's rheme interleaver carries out after the position interweaves are carried out symbol interleaving.

Above-mentioned purpose is to realize by the sending method that a kind of digit broadcasting system is provided, and this sending method comprises step: (a) respectively first and second input transmission (TS) streams are carried out error correction coding and exported first and second coded datas; (b) execution interweaves to first and second coded datas respectively, and exports first and second interleaving datas; (c) respectively first and second interleaving datas are carried out coding; (d) interweave to carrying out the position from first and second coded datas of step (c); (e) use the predetermined interleaving address that provides in the question blank (LUT) that the data that interweave through the position are carried out symbol interleaving; And the data that (f) the process interleaver interweaved are carried out digital modulation and are sent data.

Step (e) is carried out symbol interleaving based on the predetermined interleaving address that provides to the data that interweave through the position in question blank.

Step (f) uses OFDM to carry out digital modulation.

Step (f) comprises step: (f1) shine upon the data that interweave through interleaver and carry out the OFDM modulation by mapping method; (f2) be provided for the pilot signal of signal Synchronization and signal estimation and the information of relevant sending mode to the data in mapping/OFDM modulation step; (f3) GI is inserted into the signal of exporting from mapping/OFDM modulation step; (f4) signal that has inserted GI is carried out the D/A conversion; And (f5) will become high-frequency signal and send this signal through the conversion of signals of D/A conversion.

In step (a) before, described method also comprises step: respectively the first and second TS streams are carried out scrambling.

Step (a) uses Rui De-Saloman (RS) sign indicating number to encode.

According to the present invention, the randomness of interleaver can interweave and uses the symbol interleaving of specific randomized LUT to improve by carrying out by carrying out position according to the convolutional interleave method.Therefore, can improve the error correction coding performance at receiver place.

Description of drawings

To the detailed description of the preferred embodiments of the present invention, it is clearer that above-mentioned purpose of the present invention and advantage will become by with reference to the accompanying drawings, wherein:

Fig. 1 is the block diagram according to the dispensing device of the digit broadcasting system of the embodiment of the invention;

Fig. 2 mode by way of example shows the symbol interleaver of the Fig. 1 that uses question blank (LUT);

Fig. 3 is the flow chart of method of operation of dispensing device of the digit broadcasting system of Fig. 1; And

Fig. 4 is the block diagram of the dispensing device of digit broadcasting system in accordance with another embodiment of the present invention.

Embodiment

Hereinafter, will be with reference to the accompanying drawings, describe the preferred embodiments of the present invention in detail.

Fig. 1 is the block diagram according to the dispensing device of the digit broadcasting system of the embodiment of the invention.

With reference to Fig. 1, comprise according to the dispensing device of the digit broadcasting system of this embodiment: first and

second scramblers

10 and 11, forward error correction (FEC) unit 40 and modulating unit 50.FEC unit 40 comprises: first and second

outer encoders

12 and 22, first and second

external interleavers

14 and 24, first and second

inner encoders

16 and 26 and interleaver 30.Modulating unit 50 comprises: pilot tone/system information is inserted piece 51, mapping/OFDM modulator block 53, protection (GI) insertion piece 55, digital simulation (D/A) conversion block 57 and radio frequency (RF) piece 59 at interval.

According to this embodiment, the dispensing device of this digit broadcasting system is supported the Delamination Transmission pattern, so the separator (not shown) is divided into high priority (HP) layer and low priority (LP) layer with transport stream (TS stream).A TS stream that sends by the HP layer is input to first scrambler 10, and the 2nd TS stream that sends by the LP layer is input to second scrambler 11.

First and

second scramblers

10 and 11 are according to the data value randomization of preassigned pattern with the first and second input TS streams.That is,, can remove the correlation between the input signal by the pseudo-random binary sequence scrambling being become input TS stream.This has prevented because the problem that the system synchronization that the repeating data such as 00000000b or 11111111b during the transmission synchrodata causes is lost.Reversibly carry out this processing at the receiver place to recover original value.

The 40 pairs of data by first and

second scramblers

10 and 11 inputs in FEC unit are carried out coding to be corrected in the mistake that occurs during data send.That is, first and second

outer encoders

12 and 22 use the RS coding to receive from the data of first and

second scramblers

10 and 11 outputs, and these data are pressed block unit carry out the RS coding so that error correction.RS coding adds the parity check code that is used for error correction, is same to each other or different to each other by the size of first and second

outer encoders

12 and 22 parity check codes that add.

First and second

external interleavers

14 and 24 pairs first and second

outer encoders

12 and 22 are carried out by each data of module unit coding and are interweaved, and thus, break up potential burst error.First and second

inner encoders

16 and 26 are pressed the data execution convolutional encoding of block interleaving respectively to first and second

external interleavers

14 and 24.

Interweaved once more by interleaver 30 by first and second

inner encoders

16 and 26 coded datas.

Interleaver 30 has an interleaver 31 and symbol interleaver 33.Position interleaver 31 uses traditional position interleaver to interweave.Therefore, this paper omits the structure and the operation of an interleaver 31.

Fig. 2 shows the more detailed block diagram of using question blank (LUT) to carry out the symbol interleaver 330 that interweaves.

Symbol interleaver 330 comprises: first and second switches 331 and 337, and control it by predetermined control signal and open and close; First and second memories 335 and 336 are used to read and write the OFDM symbolic unit stream (available data symbol number) of input; Address generator 332, the interleaving address that is used for providing according to LUT produces the address; And controller 338, the interleaving address that is used for providing with LUT is controlled reading and write operation of first and second memories 335 and 336 accordingly.

First and second memories 335 and 336 size (interlacing frames) are determined according to 2K, 4K and 8K FFT pattern.Therefore for example, when 2K FFT pattern, the data available symbolic number is 1512, and first and second memories 335 and 336 size (frame number interweaves) are 1512, and correspondingly, the frame number that interweaves of 8K FFT pattern is 6048 (1512 * 4).That is, interweave by the OFDM symbolic unit execution that constitutes by 1512 data available symbols.

For example, under the control of controller 338, when the 2nd OFDM symbol of input write first memory 335, second memory 336 read and exports the OFDM symbol in preceding input.When first memory 335 used the interleaving address that produces based on LUT in address generator 332 that the 2nd OFDM symbol of being imported is write, second memory 336 used the interleaving address that produces based on LUT to read and export an OFDM symbol that writes in second memory 336.As mentioned above, when a memory was in reading state, another memory was in write state, thereby pressed OFDM symbolic unit interleaving data.

50 pairs of data combine digital modulation that interweaved by the interleaver 30 that improves randomness of modulating unit, this digital modulation is suitable for the sending method of described digit broadcasting system.Fig. 1 mode by way of example shows the modulation based on for example DVB-T that modulating unit 50 is carried out.

The mapping of modulating unit 50/OFDM modulator block 53 will become the symbol such as QPSK (Quadrature Phase Shift Keying), 16-QAM (quadrature amplitude modulation) and 64-QAM from the data map of interleaver 30 outputs, and use IFFT (invert fast fourier transformation) to carry out the OFDM modulation.Before carrying out the OFDM modulation, pilot tone/system information is inserted piece 51 insertions and is used for the pilot signal of signal Synchronization and signal estimation and the information of relevant sending mode.GI inserts piece 55 and inserts the protection interval (GI) that prevents intersymbol interference in the multi-path environment (ISI).And 57 pairs of D/A conversion blocks have inserted the conversion of the signal combine digital of GI to simulation (D/A), and RF piece 59 will be amplified to high frequency through the signal of D/A conversion, and by this signal of antenna transmission.

Fig. 3 is the flow chart of the method for operation of dispensing device according to digit broadcasting system of the present invention shown in Figure 1.

With reference to this flow chart, the separator (not shown) is divided into TS stream that sends by high priority (HP) layer and the 2nd TS stream that sends by low priority (LP) layer with the transport stream (TS stream) of input.The one TS stream is input to first scrambler 10, and carries out scrambling by first scrambler 10, and the 2nd TS stream is input to second scrambler 11, and by second scrambler, 11 scramblings (S100).First and second

outer encoders

12 and 22 pairs of data from first and

second scramblers

10 and 11 scramblings output are pressed block unit and are carried out the RS coding so that error correction (S200).

According to the RS coding, a piece that comprises k incoming symbol is encoded into the piece with n code sign, and wherein n is greater than k.Therefore, added n-k redundant symbol, it is called as Rui De-Saloman parity check code.The quantity of the parity check code that adds by RS coding depends on transmitting system, and for example, the symbol of each 188 byte adds 16 or 20.The data that the RS decoder uses the parity check code inspection to receive.If as check result for detecting mistake, then the position of this RS decoder searches mistake, correct the data of distortion and recover original symbol.Usually, the number of errors of correction be at most add half of parity check number of codes, and can not correct exceed add the mistake of half quantity of parity check number of codes.

First and second

external interleavers

14 and 24 pairs first and second

outer encoders

12 and 22 are carried out outer interweave (S300) by the block unit coded data.In the method for first and second external interleavers 14 and the 24 various interleaving datas that use, use convolutional deinterleaver usually.

First and second

inner encoders

16 and 26 pairs of data from first and second

external interleavers

14 and 24 outputs are carried out convolutional encoding (S400).The line of input that convolution code is used for the k position that each is continuous is encoded into n carry-out bit, and should be made up of the convolution of input position and binary pulse response by coding.The DVB-T transmitting system use have limited length be 7 and encoding rate be 1/2 convolution coder.At this, adopt first and second inner encoders 16 of convolution coder and 26 encoding rate to change, for example be 2/3,3/4,5/6 and 7/8.

31 pairs of the interleavers in position of interleaver 30 are from the data execute bits of first and second

inner encoders

16 and 26 outputs interweave (S500).After this, use the interleaving address that produces based on LUT as shown in Figure 2, the data after contraposition interweaves are by symbolic unit interweave (S600).

For by having the data that the interleaver 30 that improves randomness carries out error correction coding, modulating unit 50 is carried out and is suitable for the digital modulation that data send, and sends these data (S700).

Fig. 4 is the dispensing device of digit broadcasting system according to a further advantageous embodiment of the invention.

In Fig. 4, except using the first and second interleaver 30-1 and 30-2, remainder is identical with Fig. 1's, omits the explanation of same section at this.

The first interleaver 30-1 comprises first the interleaver 31-1 and the first symbol interleaver 33-1, interweaved once more by the first interleaver 30-1 by first inner encoder, 16 coded datas, first interleaver 31-1 step-by-step carried out and interweaved, and the first symbol interleaver 33-1 interweaves by the symbol execution of carrying in the OFDM subcarrier.

The second interleaver 30-2 comprises second the interleaver 31-2 and the second symbol interleaver 33-2, is interweaved once more by the second interleaver 30-2 by second inner encoder, 26 coded datas.Second interleaver 31-2 step-by-step carried out and interweaved, and the second symbol interleaver 33-2 interweaves by the symbol execution of carrying in the OFDM subcarrier.

The structure of first and second interleaver 31-1 and 31-2 is identical with the position interleaver 31 of Fig. 1, and the structure of the first and second symbol interleaver 33-1 and 33-2 is identical with the symbol interleaver 33 of Fig. 1.

Therefore, the randomness of the interleaver 30 of the dispensing device by improving digit broadcasting system can be improved the error correction coding performance of receiver.

The foregoing description and advantage only are exemplary, are not limited to the present invention.This explanation can easily be applied to the device of other type.Specification of the present invention attempts to describe rather than limit the scope of claims.To those skilled in the art, it is obvious obtaining various deformation, improvement and change.In claims, device adds the statement of function and attempts to cover the structure of the described function of execution as described herein, and is not only structural equivalence, also comprises structure of equal value.

Claims

1. the dispensing device of a digit broadcasting system comprises:

First and second outer encoders are carried out coding to first and second transport stream of input respectively;

First and second external interleavers, execution interweaves to the first and second outer encoder coded datas respectively;

First and second inner encoders are carried out coding to the data that first and second external interleavers interweave respectively;

Interleaver, comprise: the position interleaver, be used for the first and second inner encoder coded data execute bits are interweaved, and symbol interleaver, the data that the predetermined interleaving address contraposition interleaver that is used for using question blank to provide carries out after the position interweaves are carried out symbol interleaving; And

Modulating unit, the data that are used for that interleaver is interweaved carry out digital modulation and send this data.

2. dispensing device as claimed in claim 1, wherein symbol interleaver comprises:

First and second memories are used for reading and write the data that interweaved by the position interleaver by symbolic unit;

Address generator is used for producing interleaving address based on question blank; And

Controller is used for the control address generator, makes reading with write operation of first and second memories carry out according to interleaving address.

3. dispensing device as claimed in claim 1, wherein modulating unit uses OFDM to carry out digital modulation.

4. dispensing device as claimed in claim 1, wherein modulating unit comprises:

Mapping/OFDM modulator block is used for according to mapping method the data that interleaver interweaves being shone upon, and carries out the OFDM modulation;

Pilot tone/system information is inserted piece, is provided for the pilot signal of signal Synchronization and signal estimation and the information of relevant sending mode to mapping/OFDM modulator block;

Protection is inserted piece at interval, is used for protection is inserted at interval from the signal of mapping/OFDM modulator block output;

Numeral is used for having inserted protection signal combine digital at interval to analog-converted to the analog-converted piece; And

Radio block is used for and will becomes high-frequency signal and send this signal through the conversion of signals of numeral to analog-converted.

5. dispensing device as claimed in claim 1 also comprises:

First and second scramblers are used for respectively first and second transport stream being carried out randomization, so that first and second transport stream after the randomization are provided to first and second outer encoders.

6. dispensing device as claimed in claim 1, wherein first and second outer encoders are to use the Rui De-solomon encoder of Rui De-Solomon code.

7. dispensing device as claimed in claim 1 also comprises second interleaver, comprising: second interleaver is used for the second inner encoder coded data execute bit is interweaved; And second symbol interleaver, the predetermined interleaving address that is used for using question blank to provide carries out symbol interleaving to the data that second interleaver carries out after the position interweaves.

8. dispensing device as claimed in claim 7, wherein second symbol interleaver comprises:

First and second memories are used for reading and write the data that interweaved by second interleaver by symbolic unit;

9. the sending method of a digit broadcasting system comprises step:

(a) respectively the first and second input transport stream are carried out error correction coding and exported first and second coded datas;

(b) execution interweaves to first and second coded datas respectively, and exports first and second interleaving datas;

(c) respectively first and second interleaving datas are carried out coding;

(d) interweave to carrying out the position from first and second coded datas of step (c);

(e) use the predetermined interleaving address that provides in the question blank that the data that interweave through the position are carried out symbol interleaving; And

(f) data that interweave through interleaver are carried out digital modulation and sent data.

10. sending method as claimed in claim 9 wherein in the step (e), is carried out symbol interleaving based on the predetermined interleaving address that provides to the data that interweave through the position in question blank.

11. sending method as claimed in claim 9, wherein step (f) uses OFDM to carry out digital modulation.

12. sending method as claimed in claim 9, wherein step (f) comprises step:

(f1) shine upon the data that interweave through interleaver and carry out the OFDM modulation by mapping method;

(f2) be provided for the pilot signal of signal Synchronization and signal estimation and the information of relevant sending mode to the data in mapping/OFDM modulation step;

(f3) will protect the interval to be inserted into the signal of exporting from mapping/OFDM modulation step;

(f4) to having inserted protection signal combine digital at interval to analog-converted; And

(f5) will become high-frequency signal and send this signal through the conversion of signals of numeral to analog-converted.

13. sending method as claimed in claim 9 also comprises step before in step (a):

Respectively first and second transport stream are carried out scrambling.

14. sending method as claimed in claim 9, wherein step (a) uses Rui De-Solomon code to encode.