CN104243389A - Sound wave communication method on basis of OFDM (orthogonal frequency division multiplexing) - Google Patents
Sound wave communication method on basis of OFDM (orthogonal frequency division multiplexing) Download PDFInfo
- Publication number
- CN104243389A CN104243389A CN201410500397.0A CN201410500397A CN104243389A CN 104243389 A CN104243389 A CN 104243389A CN 201410500397 A CN201410500397 A CN 201410500397A CN 104243389 A CN104243389 A CN 104243389A
- Authority
- CN
- China
- Prior art keywords
- signal
- data
- sound wave
- ofdm
- wave communication
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
The invention discloses a sound wave communication method on the basis of OFDM (orthogonal frequency division multiplexing). The sound wave communication method includes steps of modulating original data subjected to channel coding into sound wave signals of a data frame composed of a plurality of ODFM symbols, transmitting the sound wave signals via a loudspeaker, subjecting the sound waves received by a microphone to demodulating and channel decoding to restore the original data. During communication, the symbols are synchronized by pilot frequency information, the data frames are synchronized by inserting barker codes, processing is simplified, bit error rate is low, efficiency of sound wave communication is improved, the sound wave communication is developed, and the sound wave communication method has good application prospect.
Description
Technical field
The present invention relates to a kind of sound wave communication method based on OFDM, belong to wireless communication technology field.
Background technology
Frequency of sound wave can make full use of existing video/audio playback equipment and receiving system at below 24kHz, without the need to the loud speaker of specific customization and microphone, the frequency that people's ear cannot be discovered easily, can not produce more impact to daily life, therefore, sound wave communication is widely applied, but, traditional sound wave communication technical field, complex disposal process, the error rate is higher, inhibits the efficiency of sound wave communication, hinders the development of sound wave communication.
OFDM (OFDM) technology is a kind of multi-carrier digital modulation technique, although the concept of OFDM has been present in for a long time, but up to date, it is just recognized it is a kind of good method realizing two way high speed data communications by people, and be common in electric communication, also do not relate in sound wave communication technical field, how OFDM (OFDM) technology is applied in sound wave communication, with simplify processes process, reduce the error rate, improving communication efficiency, is the current technical issues that need to address.
Summary of the invention
The object of the invention is to overcome traditional sound wave communication, complex disposal process, the error rate is higher, inhibits the efficiency of sound wave communication, hinders the problem of the development of sound wave communication.Sound wave communication method based on OFDM provided by the invention, simplify process, the error rate is low, improves efficiency and the synchronism of sound wave communication, has a good application prospect.
In order to achieve the above object, the technical solution adopted in the present invention is:
Based on a sound wave communication method of OFDM, it is characterized in that: comprise the following steps,
Step (1), carries out chnnel coding by initial data, and realize expanding initial data, be expanded data;
Step (2), based on OFDM, channel is divided into some orthogonal sub-channels, comprise data-signal subchannel, constant signal subchannel, zero energy signal subspace channel and Barker code signal subspace channel, described data-signal subchannel is used for the data of transmission to assign to each data channel; Described constant signal subchannel is used for fixing transmission signal; Described zero energy signal subspace channel is used for emending frequency; It is synchronous that described Barker code subchannel is used for achieve frame;
Step (3), sign map, converts the growth data of step (1) to parallel low speed sub data flow, and is mapped as planisphere by often organizing low speed sub data flow, and the subchannel being modulated to correspondence transmits;
Step (4), carries out inverse Fourier transform in the lump by the planisphere of all subchannels, completes the conversion of frequency domain amount to time domain amount;
Step (5), to the OFDM symbol after inverse Fourier transform, carries out signal extension, obtains digital audio and video signals;
Step (6), carries out DA by digital audio and video signals and is converted to simulated audio signal, and simulated audio signal is inputed to loud speaker, and analogue audio frequency letter is wirelessly transmitted to the microphone of far-end by loud speaker;
Step (7), it is digital audio and video signals that the simulated audio signal of reception is carried out AD conversion by microphone;
Step (8), carries out Fourier transform by digital audio and video signals and realizes demodulation, completes the conversion of time domain amount to frequency domain amount, obtains the planisphere of each sub-channels;
Step (9), carries out synchronization catch to each OFDM symbol, if catch successfully, then performs step (10); If catch unsuccessfully, then slide Capture window, repeats step (8), until catch successfully;
Channel decomposing is some orthogonal sub-channels by step (10);
Step (11), symbol inverse mapping, is converted to parallel low speed sub data flow by the sub-channel data after synchronous, and the low speed sub data flow for walking abreast is converted to the identical growth data of step (1), and enters channel and transmit;
Step (12), carries out decoding to the growth data that step (11) obtains, growth data is reduced to initial data, completes acoustic communication.
The aforesaid sound wave communication method based on OFDM, it is characterized in that: step (3), sign map, planisphere is mapped as by often organizing the circulation of low speed subdata, conversion process is, each bit often organizing low speed subdata is assigned in the subchannel of its correspondence according to planisphere, by the OFDM symbol after inverse Fourier transform.
The aforesaid sound wave communication method based on OFDM, it is characterized in that: step (5), to the OFDM symbol after inverse Fourier transform, the method of carrying out signal extension is reduce the energy leakage when adjacent two OFDM symbol switch, need to copy the continuation of part original signal as transitional region, the rear transition region of previous OFDM symbol and the front transition region of a rear OFDM symbol superimposed, the gradual change window function of forward and backward transition region is followed successively by:
The aforesaid sound wave communication method based on OFDM, is characterized in that: be provided with protection interval region between described front transition region and original signal, and described protection spacer region is the continuation of original signal tail signal.
The aforesaid sound wave communication method based on OFDM, is characterized in that: step (9), carries out synchronization catch to each OFDM symbol, is provided with two kinds of seizure situations,
(1) original position of DFT window drops in Cyclic Prefix, and the value of the sample value that DFT window comprises for this reason in OFDM symbol, then do not exist and produce intersymbol interference, correct demodulation, synchronization catch success;
(2) original position of DFT window drops on outside Cyclic Prefix, the sample value that DFT window comprises contains the value of next OFDM symbol, then there is intersymbol interference, synchronization catch failure, DFT window is needed to be slided backward by sliding unit, demodulation again, so that correct demodulation, synchronization catch success.
The aforesaid sound wave communication method based on OFDM, is characterized in that: describedly slided backward by sliding unit by DFT window, and the computational process of slide displacement is,
(1) length being provided with IDFT unit generation sample of signal is L, then after expansion, the length of data is 2.75L;
The transitional region of (2) two OFDM symbol overlaps on together, and transitional region is 0.25L, then the spacing of two OFDM symbol heads is 2.75L-0.25L=2.5L;
(3) DFT length of window is L, and sliding distance is 2.5 L/2=1.25L.
The aforesaid sound wave communication method based on OFDM, it is characterized in that: each OFDM symbol is equipped with a Barker code, by Barker code successively stored in shift register, the length of shift register equals the length of Barker code, when the sharp peaks of the microphone decision level of receiving terminal occurs, judgment frame starts and end position, and achieve frame is synchronous.
The aforesaid sound wave communication method based on OFDM, is characterized in that: step (1), and initial data is carried out chnnel coding, comprises the first Bose-Chaudhuri-Hocquenghem Code, intertexture, the second Bose-Chaudhuri-Hocquenghem Code three steps.
The aforesaid sound wave communication method based on OFDM, is characterized in that: step (12), carries out decoding to the growth data that step (11) obtains, and comprises a BCH decoding, deinterleaving, the 2nd BCH decoding three steps.
The invention has the beneficial effects as follows: the sound wave communication method based on OFDM provided by the invention, initial data is launched by loud speaker by the acoustic signals being modulated into the Frame be made up of multiple OFDM symbol after chnnel coding, after separating mediation channel decoding, initial data is reduced to again after microphones to acoustic signals, in communication process, sign synchronization is realized by pilot frequency information, data-frame sync is realized by the mode inserting Barker code, simplify process, the error rate is low, improve the efficiency of sound wave communication, advance the development of sound wave communication, have a good application prospect.
Accompanying drawing explanation
Fig. 1 is the flow chart of the sound wave communication method based on OFDM of the present invention.
Fig. 2 is the flow chart of chnnel coding of the present invention.
Fig. 3 is the flow chart of channel decoding of the present invention.
Fig. 4 is that subchannel purposes of the present invention distributes schematic diagram.
Fig. 5 is the schematic diagram of growth data of the present invention.
Fig. 6 is the synchronization catch schematic diagram that the original position of DFT window of the present invention drops in Cyclic Prefix.
Fig. 7 is the synchronization catch schematic diagram that the original position of DFT window of the present invention drops on outside Cyclic Prefix.
Fig. 8 is the schematic diagram of the encoding and decoding of one embodiment of the invention.
Fig. 9 is the planisphere of the QPSK mode modulating data of one embodiment of the invention.
Figure 10 is the schematic diagram of the signal extension of one embodiment of the invention.
Figure 11 is the synchronization catch of one embodiment of the invention and the schematic diagram of slip.
Embodiment
Below in conjunction with Figure of description, the invention will be further described.Following examples only for technical scheme of the present invention is clearly described, and can not limit the scope of the invention with this.
As shown in Figure 1, the sound wave communication method based on OFDM of the present invention, comprises the following steps,
Step (1), carries out chnnel coding by initial data, and realize expanding initial data, be expanded data; Here initial data, namely the content-data of the information sent is needed, it can be any binary data, include but not limited to the data of the types such as word, picture, video, audio frequency, digital audio-frequency data produces in signal debugging module, and expansion by adding monitoring data, the error accumulated in communication process to be corrected;
Step (2), based on OFDM, channel is divided into some orthogonal sub-channels, comprise data-signal subchannel, constant signal subchannel, zero energy signal subspace channel and Barker code signal subspace channel, described data-signal subchannel is used for the data of transmission to assign to each data channel; Described constant signal subchannel is used for the fixing signal that sends and is used for OFDM symbol synchronously, sign synchronization success, correctly by the planisphere inverse mapping of data channel, if sign synchronization failure, can need slip demodulation window until synchronously success; Described zero energy signal subspace channel is used for emending frequency; It is synchronous that described Barker code subchannel is used for achieve frame;
Step (3), sign map, converts the growth data of step (1) to parallel low speed sub data flow, and is mapped as planisphere by often organizing low speed sub data flow, and the subchannel being modulated to correspondence transmits;
Step (4), carries out inverse Fourier transform in the lump by the planisphere of all subchannels, completes the conversion of frequency domain amount to time domain amount;
Step (5), to the OFDM symbol after inverse Fourier transform (IDFT), carries out signal extension, obtains digital audio and video signals;
Step (6), carries out DA by digital audio and video signals and is converted to simulated audio signal, and simulated audio signal is inputed to loud speaker, and analogue audio frequency letter is wirelessly transmitted to the microphone of far-end by loud speaker;
Step (7), it is digital audio and video signals that the simulated audio signal of reception is carried out AD conversion by microphone;
Step (8), carries out Fourier transform (DFT) and realizes demodulation, complete the conversion of time domain amount to frequency domain amount, obtain the planisphere of each sub-channels by digital audio and video signals;
Step (9), carries out synchronization catch to each OFDM symbol, if catch successfully, then performs step (10); If catch unsuccessfully, then slide Capture window, repeats step (8), until catch successfully;
Channel decomposing is some orthogonal sub-channels by step (10);
Step (11), symbol inverse mapping, is converted to parallel low speed sub data flow by the sub-channel data after synchronous, and the low speed sub data flow for walking abreast is converted to the identical growth data of step (1), and enters channel and transmit;
Step (12), carries out decoding to the growth data that step (11) obtains, growth data is reduced to initial data, completes acoustic communication.
By carrying out transfer of data lower than below 24kHz communication channel between described loud speaker and microphone, here frequency of sound wave can make full use of existing video/audio playback equipment and receiving system at below 24kHz, without the need to the loud speaker of specific customization and microphone, the frequency that people's ear cannot be discovered easily, can not produce more impact to daily life;
As shown in Figure 2, step (1), channel coding process, comprises the first Bose-Chaudhuri-Hocquenghem Code, intertexture, the second Bose-Chaudhuri-Hocquenghem Code three steps, realizes expanding initial data, data after being expanded;
As shown in Figure 3, step (12), channel decoding process, comprises a BCH decoding, deinterleaving, the 2nd BCH decoding three steps, realizes data convert after expansion to become initial data;
Audio frequency digital signal is in the transmission often due to a variety of causes, make to produce error code in the data flow transmitted, by this link of channel coding and decoding module, logarithmic code stream processes accordingly, there is certain error correcting capability and antijamming capability, the generation of error code in can greatly avoiding code stream to transmit;
Step (3), meet mapping, after packet, often will organize data-mapping is a planisphere, detailed process is: be assigned in the subchannel of its correspondence by each bit often organizing data according to planisphere, here the frequency partition of 0-24kHz is that (signal converted by DFT is orthogonal to multiple orthogonal sub-channels certainly by step (2), the quantity dividing channel equals the half of counting of DFT), people's ear cannot be discovered easily subchannel and take out distribution as different purposes (data channel, Barker code channel, zero energy channel, constant signal channel), suppose to be 50 DFT, 25 sub-channels are divided, the bandwidth of every sub-channels is 1kHz, if the frequency that so people's ear cannot be discovered easily is 15kHz ~ 24kHz, so can by 16-25 totally 10 sub-channels go to divide different purposes, every sub-channels is all got on by data-mapping by the mode of planisphere, for example bpsk modulation then each channel can map 1bit, qpsk modulation is 2bit, 8psk modulation is 3bit, qam modulation is 4bit, the planisphere that different modulation systems is corresponding different, data signal channel, each data channel is assigned to needing the data of transmission, Barker code channel is using the position of specified point in constellation as+1 and-1, and achieve frame is synchronous, zero energy signaling channel, does not send any data, is 0, for emending frequency at this some place power, constant signal signal, the signal that fixing transmission is constant, as pilot tone (as sign synchronization, channel estimating and channel equalization), zero energy signal pilot (being used as checking sign synchronization) and Barker code signal pilot (as frame synchronization), meeting inverse mapping unit is its inverse process, and sign map as shown in Figure 4.
Step (11), meet inverse mapping process, by the intensity of constant signal channel and phase signal known, by its intensity to doing normalized to the intensity of other channels, calculate the decay of overall signal or the value of gain, side-play amount τ when can learn demodulation by formula (1)
τ＝(θ-θ’)N/2πk (1)
Wherein, sum when N is DFT; K is the kth point after conversion, i.e. kth sub-channels, and k is for N/2 conjugation; θ is the actual phase of this point; (when alignment original position, θ=θ ' draws side-play amount τ=0 according to above-mentioned formulae discovery to the phase place that θ ' calculates for (signal by receiving), when do not align original position time, namely θ and θ ' is unequal goes out side-play amount τ by above-mentioned formulae discovery);
After the intensity of other signals and phase place being revised according to constant signal, just can draw planisphere according to revised intensity and phase place, then draw the data of its correspondence according to planisphere.
The present invention directly by IDFT cells modulate, can modulate multiple subchannel simultaneously simultaneously, save high pass filter equipment, when outputting digital audio signal without the need to filtering low-pass signal.
The present invention directly by the demodulation of DFT unit, can carry out demodulation to multiple subchannel simultaneously simultaneously, save high pass filter equipment, when input digital audio signal without the need to filtering low-pass signal.
Step (5); carry out signal extension; for reducing the energy leakage when adjacent two OFDM symbol switch; as shown in Figure 5; need to copy the continuation of part original signal as transitional region; in order to ensure that the periodicity of signal needs to copy original signal tail signal as front transitional region and protection interval; copy original signal head signal as rear transitional region; the rear transition region of previous OFDM symbol and the front transition region of a rear OFDM symbol superimposed, the gradual change window function of forward and backward transition region is followed successively by:
Here the length that the gradual change window function of transitional region and stacked system shorten transitional region decreases the value of energy leakage simultaneously, and when symbol is switched, people's ear cannot be discovered easily.
Be provided with protection interval region between described front transition region and original signal, described protection spacer region is the continuation of original signal tail signal.
Step (9), synchronization catch process, is provided with two kinds of seizure situations, and timing slip during demodulation is τ sampling,
(1) as shown in Figure 6, the original position of DFT window drops in Cyclic Prefix, and the value of the sample value that DFT window comprises for this reason in OFDM symbol, then do not exist and produce intersymbol interference, correct demodulation, synchronization catch success;
(2) as shown in Figure 7, the original position of DFT window drops on outside Cyclic Prefix, the sample value that DFT window comprises contains the value of next OFDM symbol, then there is intersymbol interference, synchronization catch failure, needs DFT window to be slided backward by sliding unit, demodulation again, so that correct demodulation, synchronization catch success.
Describedly slided backward by sliding unit by DFT window, the computational process of slide displacement is,
(1) length being provided with IDFT unit generation sample of signal is L, then after expansion, the length of data is 2.75L, be specially, the afterbody 0.5L of replicating original signal as the head 0.25L of the complete primary signal+replicating original signal in 2L, front transitional region and protection interval+copy as rear transitional region;
The transitional region of (2) two OFDM symbol overlaps on together, and transitional region is 0.25L, then the spacing of two OFDM symbol heads is 2.75L-0.25L=2.5L;
(3) DFT length of window is L, and sliding distance is 2.5 L/2=1.25L.
Described each OFDM symbol is equipped with a Barker code, by Barker code successively stored in shift register, the length of shift register equals the length of Barker code, when the sharp peaks of the Identifier With Barker Code of receiving terminal occurs, judgment frame starts and end position, achieve frame is synchronous, Identifier With Barker Code principle: Barker code is successively stored in register simply, when the Barker code in every bit register is identical with the Barker code preset, 1 level should be exported for register, the output of every bit register is added by adder, meeting when Barker code be the output of i.e. adder is peak value.
According to the sound wave communication method based on OFDM of the present invention, introduce a specific embodiment,
Suppose that every frame sends 256bit initial data (expanding to 1024bit after chnnel coding), use 16 transfer of data subcarriers, use QPSK planisphere (2bit), then every frame data have 32 OFDM symbol (1024/16/2=32), the sampling precision of digital audio and video signals is 16bit, sample frequency is 44.1kHz, be an OFDM symbol with 640 sampled points, then the length of every frame signal is: 32*640/44100 ≈ 0.4644 (second), implementation procedure
Chnnel coding and decoding
Following cataloged procedure is carried out to the initial data of every frame:
(1) initial data is divided into 16 groups, after often group 16bit does BCH (31,16) coding, obtains the data of 496bit, then add the trailer information of 16bit;
(2) data are sent into successively by row the interleaver of 2 16 bit*16bit, then press leu time taking-up;
(3) Data Placement is 32 groups, and after often group 16bit does BCH (31,16) coding, obtain the data of 992bit, then add the trailer information of 32bit, here the process of specific design coding and decoding is the prior art of those skilled in the art
Decoding is its inverse process, encoding and decoding process, as shown in Figure 8;
Signal madulation and demodulation
(1) sign map and inverse mapping
17kHz ~ 21kHz frequency range is marked off 23 sub-channels (16 for transmission of data signals, 3 for transmitting constant signal, 2 for transmitting Barker code signal, 2 for transmitting zero energy signal).Owing to adopting 256 IDFT generate signal therefore have 128 frequencies, wherein:
Data-signal frequency is: 99,100,101,102,103,104,105,106,107,108,110,111,112,113,114,115
Constant signal frequency is: 98,119,120
Barker code signal frequency point is: 109,118
Zero energy signal frequency point is: 116,117
By QPSK mode modulating data, use planisphere as shown in Figure 9, at data-signal frequency, each frequency transmission 2bit data; At constant signal frequency, constant transmission " 11 "; Barker code signal frequency point, " 11 " expression "+", " 00 " (expression) "-", in the frame after using 13 Barker codes (in frame, each OFDM symbol sends 1, when 13 Barker codes) to be sent, (residue) OFDM symbol sends zero-signal; Zero energy signal frequency point, sends zero-signal;
(2) signal extension
By the digital audio and video signals that 256 are generated by IDFT unit, the mode done as shown in Figure 10 is expanded,
(3) synchronization catch and slip
When use 256 sample windows do the demodulation of DFT unit, demodulation window is position drop point in fact, as shown in Figure 10, the original position of demodulation DFT window between A and B time can with correct demodulation, as shown in figure 11, cannot correctly demodulation between C and D, AB=CD, namely first seizure has the probability of 50% to catch successfully, when catching unsuccessfully for the first time, only need slide backward 320 samples and get final product 100% seizure success, average 1.5 seizure can realize sign synchronization, sign synchronization efficiency is high, the situation of sign synchronization is introduced here by concrete numerical value, namely the sample length that IDFT generates is x, by expansion after length be x+x+x/2+x/4=2.75x, because the transitional region of 2 OFDM symbol in front and back overlaps on together, therefore the spacing of 2 OFDM symbol heads is 2.75x-x/4=2.5x, the DFT length of window of each demodulation is x, sliding distance is 2.5x/2=1.25x, numerical value above in citing is according to this ratio setting, just can reach average 1.5 times and catch the effect that can realize sign synchronization.
(4) frame synchronization
When receiving the 13rd OFDM symbol in frame successively, there is sharp peaks in Barker code, just can judgment frame start and end position according to this.
More than show and describe general principle of the present invention, principal character and advantage.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; what describe in above-described embodiment and specification just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.Application claims protection range is defined by appending claims and equivalent thereof.
Claims (9)
1. based on the sound wave communication method of OFDM, it is characterized in that: comprise the following steps,
Step (1), carries out chnnel coding by initial data, and realize expanding initial data, be expanded data;
Step (2), based on OFDM, channel is divided into some orthogonal sub-channels, comprise data-signal subchannel, constant signal subchannel, zero energy signal subspace channel and Barker code signal subspace channel, described data-signal subchannel is used for the data of transmission to assign to each data channel; Described constant signal subchannel is used for fixing transmission signal; Described zero energy signal subspace channel is used for emending frequency; It is synchronous that described Barker code subchannel is used for achieve frame;
Step (3), sign map, converts the growth data of step (1) to parallel low speed sub data flow, and is mapped as planisphere by often organizing low speed sub data flow, and the subchannel being modulated to correspondence transmits;
Step (4), carries out inverse Fourier transform in the lump by the planisphere of all subchannels, completes the conversion of frequency domain amount to time domain amount;
Step (5), to the OFDM symbol after inverse Fourier transform, carries out signal extension, obtains digital audio and video signals;
Step (6), carries out DA by digital audio and video signals and is converted to simulated audio signal, and simulated audio signal is inputed to loud speaker, and analogue audio frequency letter is wirelessly transmitted to the microphone of far-end by loud speaker;
Step (7), it is digital audio and video signals that the simulated audio signal of reception is carried out AD conversion by microphone;
Step (8), carries out Fourier transform by digital audio and video signals and realizes demodulation, completes the conversion of time domain amount to frequency domain amount, obtains the planisphere of each sub-channels;
Step (9), carries out synchronization catch to each OFDM symbol, if catch successfully, then performs step (10); If catch unsuccessfully, then slide Capture window, repeats step (8), until catch successfully;
Channel decomposing is some orthogonal sub-channels by step (10);
Step (11), symbol inverse mapping, is converted to parallel low speed sub data flow by the sub-channel data after synchronous, and the low speed sub data flow for walking abreast is converted to the identical growth data of step (1), and enters channel and transmit;
Step (12), carries out decoding to the growth data that step (11) obtains, growth data is reduced to initial data, completes acoustic communication.
2. the sound wave communication method based on OFDM according to claim 1, it is characterized in that: step (3), sign map, planisphere is mapped as by often organizing the circulation of low speed subdata, conversion process is, each bit often organizing low speed subdata is assigned in the subchannel of its correspondence according to planisphere, by the OFDM symbol after inverse Fourier transform.
3. the sound wave communication method based on OFDM according to claim 1, it is characterized in that: step (5), to the OFDM symbol after inverse Fourier transform, the method of carrying out signal extension is reduce the energy leakage when adjacent two OFDM symbol switch, need to copy the continuation of part original signal as transitional region, the rear transition region of previous OFDM symbol and the front transition region of a rear OFDM symbol superimposed, the gradual change window function of forward and backward transition region is followed successively by:
4. the sound wave communication method based on OFDM according to claim 3, is characterized in that: be provided with protection interval region between described front transition region and original signal, and described protection spacer region is the continuation of original signal tail signal.
5. the sound wave communication method based on OFDM according to claim 3, is characterized in that: step (9), carries out synchronization catch to each OFDM symbol, is provided with two kinds of seizure situations,
(1) original position of DFT window drops in Cyclic Prefix, and the value of the sample value that DFT window comprises for this reason in OFDM symbol, then do not exist and produce intersymbol interference, correct demodulation, synchronization catch success;
(2) original position of DFT window drops on outside Cyclic Prefix, the sample value that DFT window comprises contains the value of next OFDM symbol, then there is intersymbol interference, synchronization catch failure, DFT window is needed to be slided backward by sliding unit, demodulation again, so that correct demodulation, synchronization catch success.
6. the sound wave communication method based on OFDM according to claim 5, is characterized in that: describedly slided backward by sliding unit by DFT window, and the computational process of slide displacement is,
(1) length being provided with IDFT unit generation sample of signal is L, then after expansion, the length of data is 2.75L;
The transitional region of (2) two OFDM symbol overlaps on together, and transitional region is 0.25L, then the spacing of two OFDM symbol heads is 2.75L-0.25L=2.5L;
(3) DFT length of window is L, and sliding distance is 2.5 L/2=1.25L.
7. the sound wave communication method based on OFDM according to claim 1, it is characterized in that: each OFDM symbol is equipped with a Barker code, by Barker code successively stored in shift register, the length of shift register equals the length of Barker code, when the sharp peaks of the Identifier With Barker Code of receiving terminal occurs, judgment frame starts and end position, and achieve frame is synchronous.
8. the sound wave communication method based on OFDM according to claim 1, is characterized in that: step (1), and initial data is carried out chnnel coding, comprises the first Bose-Chaudhuri-Hocquenghem Code, intertexture, the second Bose-Chaudhuri-Hocquenghem Code three steps.
9. the sound wave communication method based on OFDM according to claim 1, it is characterized in that: step (12), decoding is carried out to the growth data that step (11) obtains, comprises a BCH decoding, deinterleaving, the 2nd BCH decoding three steps.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410500397.0A CN104243389B (en) | 2014-09-25 | 2014-09-25 | Sound wave communication method based on OFDM |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410500397.0A CN104243389B (en) | 2014-09-25 | 2014-09-25 | Sound wave communication method based on OFDM |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104243389A true CN104243389A (en) | 2014-12-24 |
| CN104243389B CN104243389B (en) | 2018-02-02 |
Family
ID=52230757
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410500397.0A Active CN104243389B (en) | 2014-09-25 | 2014-09-25 | Sound wave communication method based on OFDM |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104243389B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104868956A (en) * | 2015-04-14 | 2015-08-26 | 陈景竑 | Sound wave channel based data communication method |
| CN108631884A (en) * | 2018-05-15 | 2018-10-09 | 浙江大学 | A kind of sound wave communication method based on nonlinear interaction |
| CN114172776A (en) * | 2021-11-06 | 2022-03-11 | 青岛鼎信通讯股份有限公司 | Timing synchronization method based on medium-voltage carrier system |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040001553A1 (en) * | 2002-07-01 | 2004-01-01 | Jack Steentra | Communication using audible tones |
| CN1494244A (en) * | 2002-10-31 | 2004-05-05 | 电子科技大学 | Method of proceeding OFDM rapid synchronization using Barke code and training sequence |
| CN101390315A (en) * | 2006-02-22 | 2009-03-18 | 株式会社Ntt都科摩 | Acoustic signal transmission system, modulation device, demodulation device, and acoustic signal transmission method |
| CN101631099A (en) * | 2009-08-05 | 2010-01-20 | 华南理工大学 | Multi-input and multi-output selectivity OFDM underwater sound communication system and method |
-
2014
- 2014-09-25 CN CN201410500397.0A patent/CN104243389B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040001553A1 (en) * | 2002-07-01 | 2004-01-01 | Jack Steentra | Communication using audible tones |
| CN1494244A (en) * | 2002-10-31 | 2004-05-05 | 电子科技大学 | Method of proceeding OFDM rapid synchronization using Barke code and training sequence |
| CN101390315A (en) * | 2006-02-22 | 2009-03-18 | 株式会社Ntt都科摩 | Acoustic signal transmission system, modulation device, demodulation device, and acoustic signal transmission method |
| CN101631099A (en) * | 2009-08-05 | 2010-01-20 | 华南理工大学 | Multi-input and multi-output selectivity OFDM underwater sound communication system and method |
Non-Patent Citations (2)
| Title |
|---|
| 田文鹤: "OFDM技术在周期性钻柱中信息传输的研究与应用", 《中国优秀硕士学位论文全文数据库（基础科学辑）》 * |
| 陈杰: "基于OFDM的多用户接入及同步技术研究", 《中国优秀硕士学位论文全文数据库（信息科技辑）》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104868956A (en) * | 2015-04-14 | 2015-08-26 | 陈景竑 | Sound wave channel based data communication method |
| CN104868956B (en) * | 2015-04-14 | 2017-12-26 | 陈景竑 | Data communications method based on sound wave channel |
| CN108631884A (en) * | 2018-05-15 | 2018-10-09 | 浙江大学 | A kind of sound wave communication method based on nonlinear interaction |
| CN114172776A (en) * | 2021-11-06 | 2022-03-11 | 青岛鼎信通讯股份有限公司 | Timing synchronization method based on medium-voltage carrier system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104243389B (en) | 2018-02-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104243388B (en) | Acoustic communication system based on OFDM | |
| US7881398B2 (en) | FFT numerology for an OFDM transmission system | |
| CN108092712B (en) | Visible light communication system, method and application apparatus based on probability shaping coding | |
| CN102484504A (en) | Transmitter and method for applying multi-tone OFDM based communications within a lower frequency range | |
| WO2006090742A1 (en) | Code type transmitting device, and code type receiving device | |
| CN105357160A (en) | Method and device for sending reference signal, and method and device for receiving reference signal | |
| WO2010091617A1 (en) | Mobile multimedia broadcast transmission system | |
| WO2010091618A1 (en) | Mobile multimedia broadcast transmission system | |
| US11546193B2 (en) | Data compression method and apparatus | |
| CN104243389A (en) | Sound wave communication method on basis of OFDM (orthogonal frequency division multiplexing) | |
| CN103595677A (en) | A method and an apparatus for beacon signal generation in a communication system | |
| CN1984110B (en) | Method for decreasing peak equilibrium ratio and orthogonal frequency division multiplexing system | |
| CN106100810A (en) | Communicator and method based on carrier aggregation technology | |
| CN103581096A (en) | OFDM modulating and demodulating method and digital signal emitting and receiving system | |
| CN106972891B (en) | Digital modulation method, digital transmission device and equipment | |
| CN103259758B (en) | A kind of ofdm communication system based on companding and method | |
| WO2010091620A1 (en) | Mobile multimedia broadcast transmission system | |
| CN107733830B (en) | Method, device and system for generating multi-carrier signal | |
| CN103825855A (en) | Method reducing peak average power ratio in OFDM system based on amplitude limiting technology | |
| CN106899400A (en) | Bursty data frame sending method and device | |
| CN103051580A (en) | Transmission method of uplink control channel in TDMA (Time Division Multiple Address, system | |
| WO2020016397A1 (en) | A method and a device to generate an amplitude-based modulation wireless signal using ofdm to be received by a low-power non-coherent receiver | |
| CN102957635B (en) | Based on digital broadband communication means and the system of information block transmission | |
| CN105453607A (en) | Transmission method and transmission equipment for wireless local area network | |
| CN110808752A (en) | Communication method and system of Internet of things |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |