CN1490944A - Sectional demodifying computing method for effectively reducing interfaces between sub-carrier - Google Patents
Sectional demodifying computing method for effectively reducing interfaces between sub-carrier Download PDFInfo
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- CN1490944A CN1490944A CNA031573886A CN03157388A CN1490944A CN 1490944 A CN1490944 A CN 1490944A CN A031573886 A CNA031573886 A CN A031573886A CN 03157388 A CN03157388 A CN 03157388A CN 1490944 A CN1490944 A CN 1490944A
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- 230000011218 segmentation Effects 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims abstract description 8
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 238000005516 engineering process Methods 0.000 abstract description 3
- 230000009466 transformation Effects 0.000 abstract 1
- 230000005540 biological transmission Effects 0.000 description 8
- 230000009897 systematic effect Effects 0.000 description 5
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L25/03159—Arrangements for removing intersymbol interference operating in the frequency domain
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
- H04L25/03006—Arrangements for removing intersymbol interference
- H04L2025/0335—Arrangements for removing intersymbol interference characterised by the type of transmission
- H04L2025/03375—Passband transmission
- H04L2025/03414—Multicarrier
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Abstract
The segmentation demodulation method that efficiently lowers the interference between the subcarrier ( ICI ) belongs to OFDM modulation and demodulation technology field, the feature is: divides OFDM symbol time domain of a N point into several segment, every segment adds zero to N point and makes FFT transformation, then makes frequency domain equilibrium adding. It increases the frequency deviation and expending width of frequency in system tolerance.
Description
Technical field
Effectively reduce and disturb the segmentation demodulation method of (ICI) to belong to PFDM system modulation demodulation techniques field between subcarrier.
Background technology
In the next generation mobile communication, require to support higher data transfer rate and translational speed faster.OFDM a kind ofly can improve the availability of frequency spectrum, obtain effective multi-carrier modulation demodulation method of high-speed transfer digit rate, it utilizes the multicarrier transmission mode of quadrature, base band data is regarded as the modulating data of each subcarrier on the frequency domain, earlier base band data is adopted the IFFT conversion at transmitting terminal, be transformed into time-domain signal and arrive receiving terminal by wireless transmission channel then, transform to frequency domain and obtain each modulating data above subcarrier thereby the time-domain signal that receives is carried out the FFT conversion again.The transmission speed of the adjustment data on each subcarrier is not very high, but thereby the parallel Data transmission of multicarrier makes the transmission rate of system be greatly improved, and be quadrature between each subcarrier, so can simply use IFFT and FFT to finish the time-frequency conversion.Integrate OFDM and have that system is simple, anti-multipath disturbs, high advantages such as the availability of frequency spectrum.
But because OFDM is the multicarrier system of quadrature, so Frequency Synchronization and frequency stability all will become the key factor that influences systematic function.Under the wireless transmission channel condition of high-speed mobile, frequency displacement and frequency bandspread are all bigger, and for the OFDM multi-carrier modulation, inter-carrier interference (ICI) will produce a very large impact systematic function.Under mobile environment,, so just between each subcarrier, produced the phase mutual interference because Doppler effect has produced frequency shift (FS) and video stretching.If under quasi-static environments, channel remains unchanged in the OFDM symbol, then can not produce between subcarrier and disturb; But the OFDM modulating system is under the fast moving channel, and channel can produce very fast time change, will cause frequency displacement and frequency bandspread to produce big interference between subcarrier, thereby causes systematic function to descend.
For a long time, how to resist and disturb the emphasis that becomes a research between the subcarrier of ofdm system under the mobile environment, simple frequency domain equalization algorithm is considered from whole OFDM symbol, patient frequency displacement of institute and frequency bandspread are all smaller, when moving velocity of terminal improved, the applicable performance of these algorithms can very big destruction, makes to receive to produce large stretch of error code and mistake symbol, system can't operate as normal, and this has just limited the raising of the translational speed of wireless terminal.Especially under the many situations of number of sub carrier wave, it is bigger that the influence of other subcarrier interference that each subcarrier is subjected to can become, and it is big that the distortion of frequency domain equalization also will become.
Based on such background technology, present patent application proposes a kind of effective reduction ICI and improves a kind of scheme of frequency displacement and frequency bandspread tolerance.It is divided into several sections with many subcarriers in symbol of ofdm system, and every section utilization mid point characteristic of channel value is separately carried out frequency domain equalization, then the addition of each section demodulation result is obtained whole demodulation result.The algorithm that experiment showed, this segmentation demodulation can resist bigger frequency deviation and frequency expansion scope under lower signal to noise ratio condition, effectively reduce between subcarrier more and disturb.
Summary of the invention
The object of the present invention is to provide the segmentation demodulation method that disturbs (ICI) between a kind of effective reduction subcarrier.
The invention is characterized in: the OFDM symbol segmentation that a N is ordered is a plurality of sections, carries out the balanced addition in the laggard line frequency of FFT conversion territory that N is ordered respectively.Be on average to cut apart this cutting apart.
Emulation experiment shows: it can effectively reduce between system subcarrier disturbs, and effectively improves systematic function, and the frequency deviation that system tolerated was compared with frequency bandspread originally and is proportional to institute's segments without the multiple that system improved of crossing the segmentation demodulation.
Description of drawings
Fig. 1 segmentation demodulating algorithm flow chart
Fig. 2 zero padding details of operation
Embodiment
The entire block diagram of segmentation demodulating algorithm thinking as shown in Figure 1.This algorithm can be divided into cutting, FFT, frequency domain equalization three parts to be finished, and introduces the detailed process of various piece below respectively.
Obtaining to cut the OFDM symbol of a time domain earlier on the synchronous basis, below operation all will be finished based on the OFDM symbol.Might as well establish the OFDM symbol is the N point, and the N OFDM symbol of ordering is cut into M part with this symbol equality on time domain hereto, and every piece of data length is N/M, still keeps its corresponding data point position in former OFDM symbol, so just finishes cutting earlier and operates.
After time domain data is finished cutting, will be on time domain with total points N (accompanying drawing 2) of each piece of data zero padding to the OFDM symbol, note the first piece of data back zero padding in the time of the zero padding operation, second piece of data is 1～N/M zero padding, and 2*N/M～N zero padding not that is to say and only the N point arrived in the second piece of data back zero padding, other piece of data similar operations, that is to say the data that each part N/M is long according to its invariant position in former OFDM symbol, other position zero paddings make the length of each piece of data all become the N point.After zero padding operation is finished each piece of data carried out the FFT that N orders and transform to frequency domain, so just can on the basis that does not change original data message, obtain the frequency domain value of segment data.
Data conversion will be carried out the operation of frequency domain equalization behind frequency domain.This step will be utilized the result of OFDM channel parameter estimation.Behind the data sementation, the frequency domain channel estimated value that we get the mid point of corresponding every segment data is made the frequency domain equalization of this segment data, that is to say with the removal of the numerical value after this segment data FFT conversion and finish frequency domain equalization with the frequency domain channel estimated value of this section mid point, remove the influence of channel, recover the original transmission data message of each section.
After finishing the frequency domain equalization of each segment data, with the frequency domain value addition that each N is ordered, finish the data that promptly obtain after this operation after the segmentation demodulation, these data can prove be exactly the OFDM symbol data of original transmission in step.
Use the method for M section segmentation demodulation system's patient frequency deviation of institute and frequency bandspread can be increased approximate M doubly, reduce between system subcarrier and disturb, effectively improve systematic function.
Claims (2)
1. effectively reduce the segmentation demodulation scheme that disturbs (ICI) between subcarrier, it is characterized in that: the OFDM symbol that a N is ordered on average is divided into plurality of sections, carries out the balanced addition in the laggard line frequency of N point FFT conversion territory respectively.
2. disturb the segmentation demodulation method of (ICI) between reduction subcarrier according to claim 1, it is characterized in that: be average and cut apart described cutting apart.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 03157388 CN1246983C (en) | 2003-09-19 | 2003-09-19 | Sectional demodifying computing method for effectively reducing interfaces between sub-carrier |
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| CN 03157388 CN1246983C (en) | 2003-09-19 | 2003-09-19 | Sectional demodifying computing method for effectively reducing interfaces between sub-carrier |
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| CN1490944A true CN1490944A (en) | 2004-04-21 |
| CN1246983C CN1246983C (en) | 2006-03-22 |
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101132386A (en) * | 2007-09-24 | 2008-02-27 | 杭州国芯科技有限公司 | Interference restraining method for orthogonal frequency division multiplexing signal |
| CN1973505B (en) * | 2004-07-16 | 2010-12-08 | 富士通株式会社 | Frequency domain equalization method and device in single-carrier receiver |
| CN101478525B (en) * | 2009-02-04 | 2011-03-30 | 北京天碁科技有限公司 | Method for multi-carrier separation and multi-carrier separation apparatus |
| CN101204057B (en) * | 2005-04-21 | 2011-04-06 | 艾利森电话股份有限公司 | Time domain windowing and inter-carrier interference cancellation |
| CN101692664B (en) * | 2009-10-13 | 2012-02-08 | 清华大学 | Multi-carrier wireless transmission method for adopting discontinuous carrier wave interference code |
| CN101355541B (en) * | 2008-07-18 | 2012-02-22 | 中国人民解放军理工大学 | Blocking equalizing method for OFDM system under Quick-Change channel condition |
| CN101018219B (en) * | 2006-02-10 | 2012-07-25 | 联想(北京)有限公司 | Space frequency signal processing method |
| CN101340409B (en) * | 2008-08-20 | 2012-08-22 | 中国电子科技集团公司第五十四研究所 | Frequency domain equalizer based on sub-band splitting |
| CN101366216B (en) * | 2006-01-31 | 2013-03-27 | 三菱电机株式会社 | Communication control method, receiving station device, sending station device and communication system |
| CN101641899B (en) * | 2007-03-21 | 2013-06-12 | 高通股份有限公司 | Simplified equalization for correlated channels in OFDMA |
| CN106878221A (en) * | 2015-12-14 | 2017-06-20 | 中兴通讯股份有限公司 | The generation method and device of a kind of multi-carrier signal |
-
2003
- 2003-09-19 CN CN 03157388 patent/CN1246983C/en not_active Expired - Fee Related
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1973505B (en) * | 2004-07-16 | 2010-12-08 | 富士通株式会社 | Frequency domain equalization method and device in single-carrier receiver |
| CN101204057B (en) * | 2005-04-21 | 2011-04-06 | 艾利森电话股份有限公司 | Time domain windowing and inter-carrier interference cancellation |
| CN101366216B (en) * | 2006-01-31 | 2013-03-27 | 三菱电机株式会社 | Communication control method, receiving station device, sending station device and communication system |
| CN101018219B (en) * | 2006-02-10 | 2012-07-25 | 联想(北京)有限公司 | Space frequency signal processing method |
| CN101641899B (en) * | 2007-03-21 | 2013-06-12 | 高通股份有限公司 | Simplified equalization for correlated channels in OFDMA |
| CN101132386A (en) * | 2007-09-24 | 2008-02-27 | 杭州国芯科技有限公司 | Interference restraining method for orthogonal frequency division multiplexing signal |
| CN101132386B (en) * | 2007-09-24 | 2013-01-30 | 杭州国芯科技股份有限公司 | Interference restraining method for orthogonal frequency division multiplexing signal |
| CN101355541B (en) * | 2008-07-18 | 2012-02-22 | 中国人民解放军理工大学 | Blocking equalizing method for OFDM system under Quick-Change channel condition |
| CN101340409B (en) * | 2008-08-20 | 2012-08-22 | 中国电子科技集团公司第五十四研究所 | Frequency domain equalizer based on sub-band splitting |
| CN101478525B (en) * | 2009-02-04 | 2011-03-30 | 北京天碁科技有限公司 | Method for multi-carrier separation and multi-carrier separation apparatus |
| CN101692664B (en) * | 2009-10-13 | 2012-02-08 | 清华大学 | Multi-carrier wireless transmission method for adopting discontinuous carrier wave interference code |
| CN106878221A (en) * | 2015-12-14 | 2017-06-20 | 中兴通讯股份有限公司 | The generation method and device of a kind of multi-carrier signal |
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| CN1246983C (en) | 2006-03-22 |
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