CN102088633B - Method for detecting carrier mode - Google Patents
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- CN102088633B CN102088633B CN2009102536065A CN200910253606A CN102088633B CN 102088633 B CN102088633 B CN 102088633B CN 2009102536065 A CN2009102536065 A CN 2009102536065A CN 200910253606 A CN200910253606 A CN 200910253606A CN 102088633 B CN102088633 B CN 102088633B
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Abstract
The invention relates to a method for detecting carrier mode. The method for detecting the carrier mode is applicable to a digital terrestrial multimedia broadcast (DTMB) system. The method for detecting the carrier mode comprises the following steps of: decoding system information of a receiving frame for the first time; according to a result of the first-time decoding, performing single carrier mode judgment on the receiving frame; if the receiving frame does not belong to the single carrier mode, converting the frame into frequency domain; decoding system information of the frame for the second time; and according to a result of the second-time decoding, performing multi-carrier mode judgment on the receiving frame.
Description
Technical field
The present invention relates to digital television broadcasting, particularly about a kind of in digital ground multimedia broadcast (DTMB) system, the method for detecting single carrier mode or multi-carrier mode.
Background technology
Digital ground multimedia broadcast (Digital Terrestrial Multimedia Broadcast, be called for short DTMB) system is a kind of in the middle of the various digital television broadcasting systems, mainly is used in China.In the DTMB system, each frame (frame) or package (packet) mainly are made up of head (header) and data subject (body).Because head mainly is that (pseudorandomnumber PN) produces, and therefore, head generally also abbreviates PN as by pseudo random number.According to the difference of head length, the DTMB system mainly contains following PN specification: PN420, PN945, PN595.For example, the head length of PN420 specification is 420 symbols (symbol) or position, add 3780 symbols of data subject, so each frame always has 4200 symbols; The head length of PN945 specification is 945 symbols, add 3780 symbols of data subject, so each frame always has 4725 symbols; The head length of PN595 specification is 595 symbols, add 3780 symbols of data subject, so each frame always has 4375 symbols.
Fig. 1 shows the structure of a kind of frame of DTMB system, wherein, data subject include 4 symbols foremost, to be used to represent the frame that is transmitted be single carrier (single carrier) pattern or be multicarrier (multi-carrier) pattern.Usually, single carrier mode is represented in " 0000 ", and multi-carrier mode is then represented in " 1111 ".Because single carrier mode is that each symbol is made primary modulation, therefore generally be called the C1 pattern again; Multi-carrier mode then is that 3780 symbols are made primary modulation, therefore generally is called the C3780 pattern again.
Ensuing 32 symbols are system information (system information), and it defines shown in table one.Wherein, sequence number (or index value) 1 has defined to 24, and all the other 40 sequence numbers are then for keeping (reserved) or still undefined.Other of data subject 3744 symbols then are real data.
Table one
| Sequence number | System information | Definition |
| 1 | 0001?1110?1010?1110 0100?1000?1011?0011 | The head frame indication (strange frame number) of superframe |
| 2 | 1110?0001?0101?0001 1011?0111?0100?1100 | The head frame indication (even frame number) of superframe |
| 3 | 0111?1000?1100?1000 0010?1110?1101?0101 | 4QAM-NR, LDPC speed 0.8, interleaving mode 1 |
| 4 | 1000?0111?0011?0111 1101?0001?0010?1010 | 4QAM-NR, LDPC speed 0.8, interleaving mode 2 |
| … | ||
| 21 | 0100?0100?0000?1011 0001?0010?0001?0110 | 64QAM, LDPC speed 0.6, interleaving mode 1 |
| 22 | 1011?1011?1111?0100 1110?1101?1110?1001 | 64QAM, LDPC speed 0.6, interleaving mode 2 |
| 23 | 0001?0001?0101?1110 0100?0111?0100?0011 | 64QAM, LDPC speed 0.8, interleaving mode 1 |
| 24 | 1110?1110?1010?0001 1011?1000?1011?1100 | 64QAM, LDPC speed 0.8, interleaving mode 2 |
| 25 | 0010?1101?0110?0010 0111?1011?0111?1111 | Keep |
| 26 | 1101?0010?1001?1101 1000?0100?1000?0000 | Keep |
| … | ||
| 61 | 0100?0100?0000?1011 1110?1101?1110?1001 | Keep |
| 62 | 1011?1011?1111?0100 0001?0010?0001?0110 | Keep |
| 63 | 0001?0001?0101?1110 | Keep |
| 1011?1000?1011?1100 | ||
| 64 | 1110?1110?1010?0001 0100?0111?0100?0011 | Keep |
The frame structure of earlier figures 1 is a kind of time domain (time domain) frame structure, and the DTMB system also has another kind of frequency domain (frequency domain) frame structure, and is as shown in Figure 2.From frequency domain, 4 symbols of representing list/multi-carrier mode are the central authorities that are positioned at data subject, and its both sides are system information, and both sides then are real data outward again.If frequency domain frame structure shown in Figure 2 is converted to time domain from frequency domain, then can obtain time domain structure as shown in Figure 1.
Though single carrier and multi-carrier mode can merely be judged by above-mentioned data subject 4 symbols foremost; But; Because frame generally all can receive the interference of noise or multipath (multi-path) when transmitting, therefore often cause the pattern judgement can't carry out perhaps wrongheaded situation and take place.Therefore, need the mechanism that proposes a kind of novelty badly, be used for effectively and correctly detecting single carrier mode or multi-carrier mode.
Summary of the invention
In view of above-mentioned, one of purpose of the embodiment of the invention is to propose a kind of method of detecting single carrier/multi-carrier mode, and the transmission frame sequence that is used to judge rightly belongs to single-carrier modulated, multi-carrier modulation actually or is invalid (invalid) signal.
According to the embodiment of the invention, at first, received frame is carried out time domain equalizationization (equalization).System information with a plurality of definition is carried out the degree of correlation first time (correlation) computing with the system information of received frame respectively; To obtain a plurality of relevance degrees, wherein each relevance degree is the result that the system information of system information and the received frame of a definition is carried out degree of correlation computing; If relevance degree is greater than preset critical, then the count value with corresponding system information adds one.Repeat above two steps; Reach up to the preset number of times of carrying out; Whereby, in the middle of these count values, exist a count value to judge then that greater than a predetermined count value received frame belongs to single carrier (single carrier) pattern than the bigger perhaps maximum count value of other count value.If do not belong to single carrier mode, then convert frame into frequency domain (frequency domain), and carry out frequency domain (frequency domain) equalization changeing the territory frame.System information with a plurality of definition is carried out the degree of correlation (correlation) computing with the system information of changeing the territory frame respectively; To obtain a plurality of relevance degrees, wherein each relevance degree is the result that the system information of a definition and the system information of changeing the territory frame are carried out degree of correlation computing; If relevance degree is greater than preset critical, then the count value with corresponding system information adds one.Repeat above two steps; Reach up to the preset number of times of carrying out; Whereby, in the middle of these second count values, exist a count value to judge then that greater than a predetermined count value received frame belongs to multicarrier (multi-carrier) pattern than the bigger perhaps maximum count value of other count value.If the first time and degree of correlation computing for the second time all can't be learnt the pattern of carrier wave, judge that then frame is an invalid signals.
Description of drawings
Fig. 1 shows the structure of a kind of time domain frame of DTMB system.
Fig. 2 shows the structure of a kind of frequency domain frame of DTMB system.
Fig. 3 shows the flow chart of the embodiment of the invention, is used to detect single-carrier modulated, multi-carrier modulation or invalid signals.
[main element symbol description]
The 30A-37A step
The 30B-37B step
38 steps
Embodiment
Because in the listed system information of aforementioned table one, therefore (32) number of symbols that each system information had, has bigger fault-tolerant or noise resisting ability far more than (4) number of symbols of list/multi-carrier mode position.The embodiment of the invention promptly according to the detecting of system information, belongs to single-carrier modulated, multi-carrier modulation actually or is invalid (invalid) signal and be able to judgement transmission frame sequence.
Fig. 3 shows the flow chart of the embodiment of the invention, is used to detect single-carrier modulated, multi-carrier modulation or invalid signals.At first, at step 31A, carry out time domain equalizationization (equalization) to the system information of received frame, it mainly is to be used to reduce the influence that multipath (multi-path) causes.Then,, carry out the decoding of system information, and, judge whether institute's received frame belongs to single carrier (single carrier) pattern according to decoded result at step 30A.In the present embodiment; At step 32A; The system information (system information of table one sequence number 1 to 24) of a plurality of definition is provided, system information and institute's receiving system information of each definition is carried out the degree of correlation (correlation) or coupling (matching) computing, to obtain a relevance degree.For considering the influence that noise causes, if the relevance degree that obtains can temporarily be regarded as effective information (step 33A) greater than a certain preset critical (for example 20), at this moment, the count value that is about to the system information (sequence number) of corresponding definition adds one (step 34A); Otherwise (being that each relevance degree is neither greater than a preset critical) got back to step 31A, carry out time domain equalizationization to the system information of next received frame, till a preset execution number of times (for example 60 times) has reached (step 35A).Behind completing steps 34A, also get back to step 31A, till a preset execution number of times (for example 60 times) has reached (step 35A).
When the preset number of times of carrying out reaches, then in step 36A, judge counts that whether uniquely defined system information (sequence number) is arranged than the counts of the system information (sequence number) of other definition more the counts of the system information (sequence number) of big or maximum definition greater than a counts (for example 50 times) of being scheduled to.If the result of determination of step 36A, is then assert institute's received frame for being for effectively, and belongs to single carrier (C1) pattern (step 37A).If the result of determination of step 36A is not for, domain operation when then leaving and get into the frequency domain computing.
At first, at step 31B, carrying out frequency-domain equalization (equalization), equally also is to be used to reduce the influence that multipath (multi-path) causes.In the present embodiment, be to use frequency-domain equalizer (frequency domain equalizer, FDE) or overlapping and addition-frequency-domain equalizer (overlap andadd-frequency domain equalizer, OLA-FDE).Because FDE and OLA-FDE belong to known technology, so its details is not given unnecessary details at this.After execution of step 31B, frame will be converted to frequency domain from time domain.Then,, carry out the decoding of system information, and, judge whether institute's received frame belongs to multicarrier (multi-carrier) pattern according to decoded result at step 30B.Step 32B provides the system information (table one sequence number 1 to 24) of definition as abovementioned steps 32A, system information and institute's receiving system information of each definition is carried out the degree of correlation (correlation) or coupling (matching) computing, to obtain a relevance degree.If the relevance degree that obtains can temporarily be regarded as effective information (step 33B) greater than a certain preset critical (for example 20), at this moment, the count value that is about to the system information (sequence number) of corresponding definition adds one (step 34B); Otherwise (being that each relevance degree is neither greater than a preset critical) got back to step 31B, carries out frequency-domain equalization to the system information of next received frame, till a preset execution number of times (for example 60 times) has reached (step 35B).Behind completing steps 34B, also get back to step 31B, till a preset execution number of times (for example 60 times) has reached (step 35B).Preset critical that it should be noted that step 33A and step 33B is not necessarily identical, and the preset execution number of times of step 35A and step 35B is also not necessarily identical.
When the preset number of times of carrying out reaches, then in step 36B, judge counts that whether uniquely defined system information (sequence number) is arranged than the counts of the system information (sequence number) of other definition more the counts of the system information (sequence number) of big or maximum definition greater than a counts (for example 50 times) of being scheduled to.If the result of determination of step 36B, is then assert institute's received frame for being for effectively, and belongs to multicarrier (C3780) pattern (step 37B).If the result of determination of step 36B judges then that for not institute's received frame is an invalid signals (step 38).According to the foregoing description, according to figure place system with more information, can be effectively and the frame sequence that receives of decision correctly belong to single carrier, multicarrier actually or be invalid signals.
The above is merely the preferred embodiments of the present invention, is not to be used to limit claims of the present invention; All other do not break away from the equivalence of being accomplished under the disclosed spirit of invention and changes or modification, all should be included in the scope of appended claims.
Claims (6)
1. a method of detecting carrier mode is used for digital ground multimedia broadcast (DTMB) system, and this method comprises:
Carry out the decoding first time to the system information of at least one received frame, and, this received frame is carried out single carrier (single carrier) mode decision according to a result who decodes for the first time; And
If this received frame does not belong to single carrier (single carrier) pattern; Then convert this frame into frequency domain (frequency domain); And carry out the second time to the system information of changeing the territory frame and decode; And, this received frame is carried out multicarrier (multi-carrier) mode decision according to a result who decodes for the second time;
Wherein above-mentioned first time, decoding step comprised:
The system information of a plurality of definition is provided, the system information of each definition and the system information of this received frame is carried out the degree of correlation (correlation) computing, to obtain a relevance degree;
If this relevance degree is greater than a preset critical, then the count value of the system information of this definition accordingly adds one; And
Next received frame is repeated above two steps, reach up to a preset number of times of carrying out;
Whereby, according to these a plurality of count values, judge to carry out single carrier mode;
In first time decoding step, in the middle of these a plurality of count values, exist a count value than other count value more greatly perhaps a maximum count value judge then that greater than a predetermined count value this received frame belongs to single carrier (single carrier) pattern;
Wherein above-mentioned second time, decoding step comprised:
The system information of a plurality of definition is provided, the system information of each definition is carried out the degree of correlation (correlation) computing with the system information of this commentaries on classics territory frame respectively, to obtain a relevance degree;
If this relevance degree is greater than a preset critical, then the count value of the system information of this definition accordingly adds one; And
Next received frame is repeated above two steps, reach up to a preset number of times of carrying out;
Whereby, according to these a plurality of count values, judge to carry out multi-carrier mode;
In second time decoding step, in the middle of these count values, exist a count value than other count value more greatly perhaps a maximum count value judge then that greater than a predetermined count value this received frame belongs to multicarrier (multi-carrier) pattern.
2. the method for detecting carrier mode as claimed in claim 1 before carrying out the decoding first time, also comprises and carries out time domain equalizationization (equalization).
3. the method for detecting carrier mode as claimed in claim 1 before carrying out the decoding second time, also comprises and carries out frequency domain (frequency domain) equalization.
4. the method for detecting carrier mode as claimed in claim 3; Wherein above-mentioned frequency-domain equalization is to use frequency-domain equalizer (frequency domain equalizer; FDE) or overlapping and addition-frequency-domain equalizer (overlap and add-frequency domain equalizer, OLA-FDE).
5. the method for detecting carrier mode as claimed in claim 1, wherein above-mentioned frame belongs to PN420 specification, PN945 specification or PN595 specification.
6. the method for detecting carrier mode as claimed in claim 1 if this first time and this second time of decoding judge that this received frame does not belong to single carrier or two carrier mode, judges that then this received frame is an invalid signals.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103546400B (en) * | 2013-05-13 | 2017-02-15 | 上海数字电视国家工程研究中心有限公司 | Single-multiple carrier signal recognizing device, method and receiver |
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| CN1791193A (en) * | 2004-12-17 | 2006-06-21 | 三星电子株式会社 | Digital multimedia signal receiver and its receiving method |
| KR20060070385A (en) * | 2004-12-20 | 2006-06-23 | 삼성전자주식회사 | A digital multimedia receiver for processing the multi-carrier modulated signal and the signle-carrier modulated signal and a digital multimedia receiving method thereof |
| CN101098151A (en) * | 2006-06-30 | 2008-01-02 | Lg电子株式会社 | Method for receiving broadcasting signal |
| CN101383919A (en) * | 2004-12-17 | 2009-03-11 | 三星电子株式会社 | Digital multimedia receiver and digital multimedia receiving method thereof |
| CN101415081A (en) * | 2006-09-04 | 2009-04-22 | 上海高清数字科技产业有限公司 | Digital television ground broadcasting system receiver supporting single/multi-carrier mode and method thereof |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1791193A (en) * | 2004-12-17 | 2006-06-21 | 三星电子株式会社 | Digital multimedia signal receiver and its receiving method |
| CN101383919A (en) * | 2004-12-17 | 2009-03-11 | 三星电子株式会社 | Digital multimedia receiver and digital multimedia receiving method thereof |
| KR20060070385A (en) * | 2004-12-20 | 2006-06-23 | 삼성전자주식회사 | A digital multimedia receiver for processing the multi-carrier modulated signal and the signle-carrier modulated signal and a digital multimedia receiving method thereof |
| CN101098151A (en) * | 2006-06-30 | 2008-01-02 | Lg电子株式会社 | Method for receiving broadcasting signal |
| CN101415081A (en) * | 2006-09-04 | 2009-04-22 | 上海高清数字科技产业有限公司 | Digital television ground broadcasting system receiver supporting single/multi-carrier mode and method thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103546400B (en) * | 2013-05-13 | 2017-02-15 | 上海数字电视国家工程研究中心有限公司 | Single-multiple carrier signal recognizing device, method and receiver |
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