CN105450557A - Air sound wave communication channel equalization method and device based on channel characteristics - Google Patents
Air sound wave communication channel equalization method and device based on channel characteristics Download PDFInfo
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Abstract
The invention discloses an air sound wave communication channel equalization method and device based on channel characteristics. A frame structure, designed through the method, meets the requirements of time domain and frequency domain, and provides a basis for the combined processing of a receiving end. The method provided by the invention gives consideration to the advantages of time domain equalization and frequency domain equalization, avoids the high calculation complexity of a time domain equalization method under the condition that a channel structure is complex, improves the possibility of algorithm convergence, and also can improve the performance of frequency domain equalization in a Doppler frequency shift air sound wave channel, so as to achieve the reliable air sound wave communication in different channel environments.
Description
Technical field
The present invention relates to wireless communication technology, specifically, relate to a kind of air sound wave that utilizes and carry out the method and apparatus communicated, particularly relate to a kind of air-borne sound communication channel equalization methods based on channel characteristics and device.
Background technology
Along with the universal fast of smart terminal product and popularization, the important carrier that mobile phone has become information to transmit as a kind of mobile terminal.User can utilize mobile phone to pay, receive sound radio information etc., due to air-borne sound communication techniques can be adopted to carry out software development to realize above-mentioned functions at mobile terminals such as mobile phones, have convenience and good user experience, application prospect is very wide.
But utilize air-borne sound channel, some problems can be faced.Sound wave reflection and refraction can produce complicated multipath effect, and in addition, the Doppler effect caused due to the relative motion of receiving and dispatching process is serious.For the problems referred to above, adopt phase frequency shift key to modulate and can offset in conjunction with channel equalization technique the intersymbol interference that multipath effect brings, equilibrium can be divided into time domain equalization and frequency domain equalization two kinds of modes, wherein time domain equalization is owing to using character rate Automatic adjusument equalizer coefficients, follow the tracks of carrier phase, but when channel architecture too complexity such as channel time delay longer time, equalizer exponent number can be caused too high, the complexity calculated strengthens, and even can not restrain in some cases; Frequency domain equalization then can work under channel architecture complicated situation, but it is comparatively responsive to Doppler shift.Can find out all respectively have deficiency when time domain equalization and frequency domain equalization two kinds of modes are applied in the air-borne sound channel of complexity.
Summary of the invention
The technical problem to be solved in the present invention proposes a kind of air-borne sound communication channel equalization methods based on channel characteristics, make it to maximize favourable factors and minimize unfavourable ones, have the advantage of time domain equalization and frequency domain equalization two kinds of modes concurrently, the computation complexity of time domain equalization method under channel architecture complexity can be avoided large, improve the possibility of algorithmic statement, the performance of frequency domain equalization under Doppler shift air sound wave channel can be improved again, to realize the reliable air-borne sound wave communication under different channels environment.
In order to solve problem proposed by the invention, a kind of air-borne sound communication channel equalization methods based on channel characteristics of the present invention, be divided into transmitting terminal and receiving terminal two parts, transmitting terminal processing method concrete steps comprise:
Step one, use the Preudo-Random Sequences Generation synchronous head data of specific exponent number, it is synchronous that this synchronous head can be used for carrying out time-frequency two-dimensional at receiving terminal subsequently, obtains the Time and Frequency Synchronization information of Received signal strength, and carry out channel estimating;
Step 2, use as Frank sequence, Zadoff-Chu sequence and m sequence etc. have the sequence structure spy word UW sequence of good cycle correlation and permanent width characteristic, be used as the training sequence of receiving terminal time domain equalization and the Cyclic Prefix of frequency domain equalization, the precision of Signal estimation can also be improved further;
Step 3, set up Frame, this data frame structure comprises synchronous head, special word UW, data Data, special word UW and zero insertion ZP, and the advantage of this frame structure is the requirement simultaneously meeting time domain and frequency domain equalization, for the Combined Treatment of receiving terminal provides the foundation.
Receiving terminal processing method concrete steps comprise:
Step one, the synchronous head of received Frame to be carried out to time-frequency two-dimensional synchronous, obtains time and frequency synchronization information;
Step 2, according to time synchronization information, data intercept signal, according to frequency synchronization information, carries out Doppler shift compensation;
Step 3, carry out channel estimating;
Step 4, according to above-mentioned channel estimating, calculate channel length parameter L (unit is symbolic number) and multipath number M, and calculate channel judging operator Q
c=L × M;
Step 5, to channel judging operator Q
cadjudicate, if be greater than the threshold value of some settings, frequency domain equalization is carried out to the data after described Doppler shift compensates; Otherwise, then time domain equalization is carried out to the data after described Doppler shift compensation;
Result after step 6, output equilibrium.
As above based on the air-borne sound communication channel equalization methods of channel characteristics, carry out time-frequency two-dimensional and synchronously can adopt the method that copy is relevant, and described special word UW, operable sequence includes but not limited to Frank sequence, Zadoff-Chu sequence and m sequence etc.
Accompanying drawing explanation
Fig. 1 is the data frame structure schematic diagram that the method for the invention adopts;
Fig. 2 is the flow chart of the air-borne sound communication channel equalization methods based on channel characteristics of the present invention;
Fig. 3 is the schematic diagram of the air-borne sound communication channel balancer based on channel characteristics of the present invention.
Embodiment
For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail.Shown in accompanying drawing and the embodiments of the present invention described with reference to the accompanying drawings be only exemplary, and the present invention is not limited to these execution modes.
It should be noted that, in order to avoid the present invention fuzzy because of unnecessary details, illustrate only in the accompanying drawings with according to the closely-related structure of the solution of the present invention and/or treatment step, and eliminate other details little with relation of the present invention.
Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.
As shown in Figure 1, according to an embodiment, the data frame structure that the method for the invention adopts comprises synchronous head, zero insertion ZP, special word UW, data Data, special word UW and zero insertion ZP.The advantage of this frame structure is the requirement simultaneously meeting time domain and frequency domain equalization, for the Combined Treatment of receiving terminal provides the foundation, wherein special word UW can be used as the Cyclic Prefix of time domain equalizing training and frequency domain equalization simultaneously, can also improve the precision of channel estimation in frequency domain equalization.
In Fig. 1, take all to put in the front and back of data segment an identical known array as special word UW, special word UW before making data Data become data Data and after the special word UW Cyclic Prefix integrally that connects, the special word before data Data also can be used for doing channel estimating and training.Special word UW sequence needs good cycle correlation and permanent width characteristic, preferably its constant amplitude and non-zero offset periodic auto-correlation function is zero.The length of Frame needs setting coherence time with reference to traffic rate in practical application and channel.
According to an embodiment, the generation step transmitted is: (1) to produce an exponent number be 9 proper polynomials is that the m sequence of 1041 is as synchronous head with shift register; (2) with shift register, to produce an exponent number be 8 proper polynomials is that the m sequence of 435 is as special word UW; (3) special word UW is placed on the front and back of data segment; (4) form complete transmitting according to the ZP signal of the frame structure insertion 50ms shown in Fig. 1 to send.
Described special word UW, operable sequence includes but not limited to Frank sequence, Zadoff-Chu sequence and m sequence etc.
In Fig. 2, in transmitting, the data frame structure adopted is as Fig. 1, specifically, adopt 9 rank m sequences (proper polynomial is 1041) as synchronizing signal (synchronous head SynchronizationHead), adopt 8 rank m sequences (proper polynomial is 435) as special word UW sequence, the length of ZP sequence is 50ms.
As shown in Figure 2, after receiving terminal receives signal, process as follows:
First the complex baseband signal using the m sequence pair of transmitting to receive carries out time-frequency two-dimensional search, the synchronous and Frequency offset estimation of acquisition time;
According to time synchronization information data intercept signal, to data-signal according to Frequency offset estimation, use the mode of linear interpolation to carry out Doppler shift compensation, and utilize the part of corresponding special word UW sequence in data-signal channel to be carried out to the channel estimating of linear MMSE criterion (LMMSE);
Utilize the channel estimated to obtain the parameters such as channel length L (unit is symbolic number) and multipath number M, and calculate channel judging operator Q
c=L × M, according to the value of judgement operator, selects to adopt time domain equalization or frequency domain equalization to process the frame data obtained;
Such as, if Q
cvalue be greater than 20, adopt frequency domain equalization, and if Q
cvalue be less than or equal to 20, then adopt time domain equalization; Finally obtain balanced output signal.
In the present embodiment, to time-domain equalizer, use 1/2 fractional gaussian noise of embedded second order digital phase-locked loop, self application track algorithm is recursive least squares (RLS), and time-domain equalizer exponent number is 40 rank.The design of this time-domain equalizer effectively can resist the intersymbol interference that multi_path channel causes, and follows the tracks of the time-varying characteristics of channel fast, ensures the reliability and stability of communication.
In the present embodiment, to frequency-domain equalizer, first the data at ZP place, end are added with the UW Received signal strength after synchronous head, obtain transmitting and channel response function circular correlation signal of equivalence, then carry out linear MMSE criterion (LMMSE) optimum channel according to the UW Received signal strength after synchronous head to estimate, the frequency domain equalizer coefficients under utilizing channel estimating to obtain minimum mean square error criterion.The design of this frequency-domain equalizer has the low feature of computation complexity, can work under channel architecture complicated situation.
Fig. 3 shows the air-borne sound communication channel balancer based on channel characteristics of the present invention.As shown in Figure 3, this device comprises Time and Frequency Synchronization unit, Doppler compensation unit, channel estimating unit, channel judging operator computing unit, identifying unit, time-domain equalizer, frequency-domain equalizer and result output unit.
Time and Frequency Synchronization unit adopts the relevant method of copy to carry out time-frequency two-dimensional synchronously to the synchronous head of received Frame, obtains time and frequency synchronization information.Doppler compensation unit is according to time synchronization information, and data intercept signal, according to frequency synchronization information, carries out Doppler shift compensation.Channel estimating unit carries out channel estimating.Channel judging operator computing unit, according to above-mentioned channel estimating, calculates channel length parameter L (unit is symbolic number) and multipath number M, and calculates channel judging operator Q
c=L × M.Identifying unit is to channel judging operator Q
cadjudicate, if be greater than the threshold value of some settings, then frequency-domain equalizer carries out frequency domain equalization to the data after described Doppler shift compensation; Otherwise then time-domain equalizer carries out time domain equalization to the data after described Doppler shift compensation.Finally, the result after result output unit output equilibrium.
It should be noted that, above embodiment is only in order to illustrate the present invention and unrestricted, although with reference to preferred embodiment, the present invention will be described in detail, those of ordinary skill in the art is to be understood that, the change carried out the present invention under the premise without departing from the spirit and scope of the present invention, amendment and distortion or equivalently to replace, all should be encompassed in the middle of right of the present invention.
Claims (20)
1., based on an air-borne sound communication channel equalization methods for channel characteristics, it comprises:
The Preudo-Random Sequences Generation synchronous head data of specific exponent number are used at transmitting terminal;
Use the sequence structure special word UW sequence with good cycle correlation and permanent width characteristic; And
Set up Frame, this data frame structure comprises synchronous head, special word UW, data Data, special word UW and zero insertion ZP.
2. the method for claim 1, wherein said special word UW sequence comprises Frank sequence, Zadoff-Chu sequence and m sequence.
3. the method for claim 1, wherein synchronous head is exponent number to be 9 proper polynomials be 1041 m sequence, special word UW sequence is exponent number to be 8 proper polynomials be 435 m sequence, the length of zero insertion ZP sequence is 50ms.
4., based on an air-borne sound communication channel balancing equipment for channel characteristics, it comprises:
For using the device of the Preudo-Random Sequences Generation synchronous head data of specific exponent number at transmitting terminal;
For using the device of the sequence structure special word UW sequence with good cycle correlation and permanent width characteristic; And
For setting up the device of Frame, this data frame structure comprises synchronous head, special word UW, data Data, special word UW and zero insertion ZP.
5. equipment as claimed in claim 4, wherein said special word UW sequence comprises Frank sequence, Zadoff-Chu sequence and m sequence.
6. equipment as claimed in claim 4, wherein synchronous head is exponent number to be 9 proper polynomials be 1041 m sequence, special word UW sequence is exponent number to be 8 proper polynomials be 435 m sequence, the length of zero insertion ZP sequence is 50ms.
7., based on an air-borne sound communication channel equalization methods for channel characteristics, it comprises:
At receiving terminal, time-frequency two-dimensional is carried out synchronously to the synchronous head of received Frame, obtain time and frequency synchronization information;
According to time synchronization information, data intercept signal, according to frequency synchronization information, carries out Doppler shift compensation;
Carry out channel estimating;
According to this channel estimating, calculate channel length parameter L and multipath number M, and calculate channel judging operator Q
c=L × M;
To channel judging operator Q
cadjudicate, if be greater than the threshold value of setting, frequency domain equalization is carried out to the data after described Doppler shift compensates; Otherwise, then time domain equalization is carried out to the data after described Doppler shift compensation; And
Export the result after equilibrium.
8. method as claimed in claim 7, wherein, described Doppler shift compensates the mode comprising and use linear interpolation.
9. method as claimed in claim 7, wherein, described channel estimating comprises and utilizes the part of corresponding special word UW sequence in data-signal to carry out linear minimum mean square error estimation to channel.
10. method as claimed in claim 7, wherein, set threshold value is 20.
11. 1 kinds of air-borne sound communication channel balancers based on channel characteristics, it comprises:
Time and Frequency Synchronization unit, carries out time-frequency two-dimensional synchronously to the synchronous head of received Frame, obtains time and frequency synchronization information;
Doppler compensation unit, according to time synchronization information, data intercept signal, according to frequency synchronization information, carries out Doppler shift compensation;
Channel estimating unit, carries out channel estimating;
Channel judging operator computing unit, according to this channel estimating, calculates channel length parameter L and multipath number M, and calculates channel judging operator Q
c=L × M;
Identifying unit, to channel judging operator Q
cadjudicate, if be greater than the threshold value of setting, frequency-domain equalizer carries out frequency domain equalization to the data after described Doppler shift compensation; Otherwise then time-domain equalizer carries out time domain equalization to the data after described Doppler shift compensation; And
Result output unit, exports the result after equilibrium.
12. devices as claimed in claim 11, wherein, time-domain equalizer uses 1/2 fractional gaussian noise of embedded second order digital phase-locked loop, and self application track algorithm is recursive least squares RLS, and time-domain equalizer exponent number is 40 rank.
13. devices as claimed in claim 11, wherein, to frequency-domain equalizer, first the data at zero insertion ZP place are added with frame head data, obtain circular correlation, then the optimum channel under least mean-square error is adopted to estimate, the frequency domain equalizer coefficients under utilizing channel estimating to obtain minimum mean square error criterion.
14. devices as claimed in claim 11, wherein, described Doppler shift compensates the mode comprising and use linear interpolation.
15. devices as claimed in claim 11, wherein, described channel estimating comprises the channel estimating utilizing the part of corresponding special word UW sequence in data-signal channel to be carried out to linear MMSE criterion.
16. devices as claimed in claim 11, wherein, set threshold value is 20.
17. 1 kinds of air-borne sound communication channel balancing equipments based on channel characteristics, it comprises:
For carrying out time-frequency two-dimensional synchronously at receiving terminal to the synchronous head of received Frame, obtain the device of time and frequency synchronization information;
For according to time synchronization information, data intercept signal, according to frequency synchronization information, carries out the device of Doppler shift compensation;
For carrying out the device of channel estimating;
For according to this channel estimating, calculate channel length parameter L and multipath number M, and calculate channel judging operator Q
cthe device of=L × M;
For to channel judging operator Q
ccarry out the device of adjudicating, if be greater than the threshold value of setting, frequency domain equalization is carried out to the data after described Doppler shift compensates; Otherwise, then time domain equalization is carried out to the data after described Doppler shift compensation; And
For exporting the device of the result after equilibrium.
18. equipment as claimed in claim 17, wherein, described Doppler shift compensates the mode comprising and use linear interpolation.
19. equipment as claimed in claim 17, wherein, described channel estimating comprises the channel estimating utilizing the part of corresponding special word UW sequence in data-signal channel to be carried out to linear MMSE criterion.
20. equipment as claimed in claim 17, wherein, set threshold value is 20.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
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| CN201410270263.4A CN105450557A (en) | 2014-06-17 | 2014-06-17 | Air sound wave communication channel equalization method and device based on channel characteristics |
| HK16105266.8A HK1217386A1 (en) | 2014-06-17 | 2016-05-09 | An air acoustic communication channel equalization method and device based on channel characteristics |
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| CN201410270263.4A CN105450557A (en) | 2014-06-17 | 2014-06-17 | Air sound wave communication channel equalization method and device based on channel characteristics |
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| CN109391573A (en) * | 2017-08-02 | 2019-02-26 | 中国科学院声学研究所 | A kind of time-frequency two-dimensional synchronous method based on linear FM signal |
| CN115118560A (en) * | 2022-06-20 | 2022-09-27 | 中国电子科技集团公司第五十四研究所 | Single carrier frequency domain equalization method based on time domain adaptive threshold noise reduction |
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| CN109391573A (en) * | 2017-08-02 | 2019-02-26 | 中国科学院声学研究所 | A kind of time-frequency two-dimensional synchronous method based on linear FM signal |
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| CN115118560A (en) * | 2022-06-20 | 2022-09-27 | 中国电子科技集团公司第五十四研究所 | Single carrier frequency domain equalization method based on time domain adaptive threshold noise reduction |
| CN115118560B (en) * | 2022-06-20 | 2023-12-29 | 中国电子科技集团公司第五十四研究所 | Single carrier frequency domain equalization method based on time domain adaptive threshold noise reduction |
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