CN105450312B - Acoustic communication sending method and device - Google Patents
Acoustic communication sending method and device Download PDFInfo
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- CN105450312B CN105450312B CN201410385343.4A CN201410385343A CN105450312B CN 105450312 B CN105450312 B CN 105450312B CN 201410385343 A CN201410385343 A CN 201410385343A CN 105450312 B CN105450312 B CN 105450312B
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Abstract
The present invention discloses a kind of acoustic communication sending methods, comprising steps of a data cell is handled as follows: setting check code；The data cell is modulated on M carrier wave by pre-arranged code rule, M is the positive integer more than or equal to 2, and the M carrier wave meets the relationship of pairwise orthogonal, and the absolute value of the frequency difference of any two carrier wave is less than or equal to 22kHz in M carrier wave；The coding rule includes phase parameter or range parameter；Synchronous code is added；Cyclic prefix is added；Generate voice signal.Inventor additionally provides corresponding acoustic communication sending device.The present invention transmits safety, and transmission process can control transmission range by adjusting speaker volume；Strong interference immunity, signal quality is high, adaptable, decays weaker, and can effectively improve the adaptability of various terminal equipment.
Description
Technical field
The present invention relates to wireless communication field, in particular to the sending method of signal processing and transmission in a kind of acoustic communication
And device.
Background technique
Communicating pair is needed to carry out before communicating such as bluetooth and WiFi currently used local, near-field communication technology
Pairing, and need additional equipment；And NFC/RIFD technology is usually also required to special equipment, and is often used for the list of data
To transmission.For the acoustic communication field technology transmitted for data, the most commonly used is ultrasonic communications, this is also required to additional dress
Setting just can be achieved, this will all cause transmission cost to improve, while also be difficult to ensure technology efficiency of the practice.
Currently, the frequency range that general portable device can play and record is 0~22KHz.It is dry in 0~2KHz frequency range
More serious (including people's one's voice in speech, the sound etc. of ambient enviroment) is disturbed, data transmission is unsuitable for.It exists in the prior art and adopts
Use the frequency range of 16KHz~22KHz as the way of communication frequency, in fact for 16KHz~18KHz frequency range, play and
Signal decaying is serious when recording, since the microphone of mobile phone and the quality of loudspeaker are irregular, such sound
Frequency range can not be adapted to all types of mobile phones well, also not be suitable for data transmission.
One publication technology, which is referred to, carries out 20Hz~20kHz for data in such a way that frequency mapping is similar to FSK
Frequency of sound wave modulation, however for guarantee data reliable transmission, need the frequency by each transmission to be maintained at 50ms；Another public affairs
Opening then needs to guarantee the transmitting continuous 40ms of frequency in patented technology, and it also requires transmitting terminal is synchronous with receiving end.As one can imagine when
When data volume is larger, the transmission time that such transmission mode needs is very big, so its efficiency is lower.
OFDM (Orthogonal Frequency Division Multiplexing) i.e. orthogonal frequency division multiplexi, it is real
OFDM is MCM (Multi Carrier Modulation), one kind of multi-carrier modulation on border.The main thought of OFDM is: will
Channel is divided into several orthogonal sub-channels, and high-speed data signal is converted into parallel low speed sub-data flow, is modulated in every height
It is transmitted on channel.Orthogonal signalling can reduce subchannel by separating in receiving end using the relevant technologies in this way
Between interfere with each other (ICI).Signal bandwidth on every sub-channels is less than the correlation bandwidth of channel, therefore on every sub-channels
Flatness decline can be regarded as, so as to eliminate intersymbol interference, and since the bandwidth of every sub-channels is only former channel
The sub-fraction of bandwidth, channel equalization become relatively easy.
OFDM modulation technique has the characteristics such as anti-interference, anti-frequency decay, is generally used for high frequency, broadband transmission field,
And it is less applied to acoustic communication field.
Summary of the invention
Based on this, it is desirable to provide a kind of acoustic communication with good terminal adaptability, high-transmission efficiency, low cost investment
Technical solution.
To achieve the above object, a kind of acoustic communication sending method is inventor provided, comprising steps of
One data cell is handled as follows:
Check code is set；
The data cell is modulated on M carrier wave by pre-arranged code rule, M is the positive integer more than or equal to 2, institute
The relationship that M carrier wave meets pairwise orthogonal is stated, and the absolute value of the frequency difference of any two carrier wave is less than or waits in M carrier wave
In 22kHz；The coding rule includes phase parameter or range parameter；
Synchronous code is added；
Cyclic prefix is added；
Generate voice signal.
Further, in the acoustic communication sending method, the data cell " is pressed pre-arranged code rule tune by step
Make on M carrier wave " it specifically includes:
Data cell is converted into one group of sequence of complex numbers by default transformation rule, and presses default selection rule from the plural number sequence
M plural number is chosen in column, and this M plural number is formed into a length with default composition rule with (N-M) a 0 as the data group of N, and
N point inverse Fourier transform is done to the data group；Wherein N > M and N=2i, i is positive integer；
It connects all inverse Fourier transform consequential signals and obtains modulation result signal.
Further, in the acoustic communication sending method, the data cell include data length, grouping number or
Packet numbering, and the numerical value of data length, grouping number or packet numbering is respectively less than or is equal to 255.
Further, in the acoustic communication sending method, the value of M is 2-64, and any two carry in M carrier wave
The absolute value range of the frequency difference of wave is 86Hz-16kHz.
Further, in the acoustic communication sending method, the value of M is 2-16, and any two carry in M carrier wave
The absolute value range of the frequency difference of wave is 750Hz-3kHz.
Further, in the acoustic communication sending method, step " generating voice signal " voice signal generated
Frequency be located at following ranges:
(93.75*0.9*k-93.75*1.1*k) Hz,
(86.13*0.9*k-86.13*1.1*k) Hz,
(78.13*0.9*k-78.13*1.1*k) Hz,
(62.5*0.9*k-62.5*1.1*k) Hz, or
(43.1*0.9*k-43.1*1.1*k) Hz, wherein k=0,1 ..., 255.
Inventor additionally provides a kind of acoustic communication sending device, including verification setup module, modulation module, synchronous code mould
Block, cyclic prefix module and sound generation module；
The correction verification module is used to that check code to be arranged to data cell；
The modulation module is used to the data cell being modulated to M carrier wave by pre-arranged code rule, M to be greater than or
Positive integer equal to 2, the M carrier wave meet the relationship of pairwise orthogonal, and in M carrier wave any two carrier wave frequency difference
Absolute value be less than or equal to 22kHz；The coding rule includes phase parameter or range parameter；
The synchronous code module is for being added synchronous code；
The cyclic prefix module is for being added cyclic prefix；
The sound generation module is for generating voice signal.
Further, in the acoustic communication sending device, modulation module is advised the data cell by pre-arranged code
It is then modulated on M carrier wave and specifically includes:
Data cell is converted into one group of sequence of complex numbers by default transformation rule, and presses default selection rule from the plural number sequence
M plural number is chosen in column, and this M plural number is formed into a length with default composition rule with (N-M) a 0 as the data group of N, and
N point inverse Fourier transform is done to the data group；Wherein N > M and N=2i, i is positive integer；
It connects all inverse Fourier transform consequential signals and obtains modulation result signal.
Further, in the acoustic communication sending device, the data cell include data length, grouping number or
Packet numbering, and the numerical value of data length, grouping number or packet numbering is respectively less than or is equal to 255.
Further, in the acoustic communication sending device, the value of M is 2-64, and any two carry in M carrier wave
The absolute value range of the frequency difference of wave is 86Hz-16kHz.
Further, in the acoustic communication sending device, the value of M is 2-16, and any two carry in M carrier wave
The absolute value range of the frequency difference of wave is 750Hz-3kHz.
Further, in the acoustic communication sending device, the frequency of sound generation module voice signal generated
Positioned at following ranges:
(93.75*0.9*k-93.75*1.1*k) Hz,
(86.13*0.9*k-86.13*1.1*k) Hz,
(78.13*0.9*k-78.13*1.1*k) Hz,
(62.5*0.9*k-62.5*1.1*k) Hz, or
(43.1*0.9*k-43.1*1.1*k) Hz, wherein k=0,1 ..., 255.
It is different from the prior art, above-mentioned technical proposal is easy to use, and transmission process is without matching, with with biography；Transmission peace
Entirely, transmission process can control transmission range by adjusting speaker volume；Strong interference immunity is resisted using OFDM modulation technique
Frequency decay, while improving the environment resistant interference performance of system；Signal quality is high, adaptable, decays weaker, and can be effective
Raising various terminal equipment adaptability, can be flexibly applied on the terminal device with microphone and/or loudspeaker, including
Android, the mobile terminal of ios, windows phone operating system and PC of windows platform etc..
Detailed description of the invention
Fig. 1 is the flow chart of acoustic communication sending method described in an embodiment of the present invention；
Fig. 2 is the structural schematic diagram of acoustic communication sending device described in an embodiment of the present invention.
Description of symbols:
21- data split module
22- verifies setup module
23- modulation module
24- synchronous code module
25- cyclic prefix module
26- sound generation module
Specific embodiment
Technology contents, construction feature, the objects and the effects for detailed description technical solution, below in conjunction with specific reality
It applies example and attached drawing is cooperated to be explained in detail.
Referring to Fig. 1, for the flow chart of acoustic communication sending method described in an embodiment of the present invention；The method includes
Following steps:
S11, data to be sent are split by preset length condition, obtains several data cells.
In this step, particular content to be sent is selected or edited first, calculates the length of data to be sent, then root
Data to be sent are split with the length for being no more than 40 bytes according to the setting of system in practical application, obtain several data
Unit.Subsequent data processing will all be carried out respectively as unit of each data cell.In the original length sheet of data to be sent
When body has just met preset length condition, this step can be saved.
S12, check code is arranged to data cell.
In this step, each data cell after splitting is marked first, then the end of data cell with
1bit is that unit is set to the corresponding bit of front end data grouping.It is the data demodulation of receiving end by the way that check code is arranged
The foundation of redundancy error check is provided.The verification mode includes even-odd check, odd-even difference parity check sum CRC cyclic redundancy check,
It can also be that other can reach the conventional method of data check purpose.
S13, the data cell is modulated on M carrier wave by pre-arranged code rule.
This step specifically includes:
Data cell is converted into one group of sequence of complex numbers by default transformation rule, and presses default selection rule from the plural number sequence
M plural number is chosen in column, and this M plural number is formed into a length with default composition rule with (N-M) a 0 as the data group of N, and
N point inverse Fourier transform is done to the data group；Wherein N > M and N=2i, i is positive integer；
It connects all inverse Fourier transform consequential signals and obtains modulation result signal.
The default transformation rule can be BPSK or QPSK.It converts, then adjusts " 0 " in Serial No. according to BPSK
It is made as " -1 ", " 1 " in Serial No. is modulated to " 1 ", to obtain positive and negative staggered bpsk signal；It is converted according to QPSK,
" 00 " in sequence is then modulated to " -1-i ", " 01 " is modulated to " -1+i ", and " 10 " are modulated to " 1-i ", and " 11 " are modulated to " 1+
I " facilitates the carrier modulation of follow-up data to obtain the QPSK data flow of four phases, provides safeguard for data transmission.
The default selection rule may include choosing the initial position of M plural number from the sequence of complex numbers or choosing to advise
Rule, such as from sequence of complex numbers i1-i10In select 3 plural numbers, can be i1,i2,i3, can be i5,i6,i7, can be i4,i8,
i10, it is also possible to i9,i3,i7。
The default composition rule includes position of (N-M) a 0 in the data group that length is N, such as is somebody's turn to do (N-M)
A 0 is located at the front end for the data group that length is N, positioned at the rear end for the data group that length is N, or the data group for being N positioned at length
Centre.
Preferred default composition rule is that will be somebody's turn to do the centre that (N-M) a 0 is placed in the data group that length is N.For example, working as N=
When 10, M=6,0 number is 4, and according to the preferred composition rule, which is the data group arrangement mode of N are as follows: a1,a2,
a3,0,0,0,0,a4,a5,a6,.Wherein a1-a6For valid data.This rule that preferably constitutes is beneficial in that, practical to grasp
In work, it is maximum positive frequency value and negative frequency value, both ends 0 that the result feature that part fft is converted, which is centre,；And 0 is set
In centre, then treatment effect, which is equivalent to, has taken continuous-L-+L frequency values can after the operation for moving 0-22k frequency range
To obtain a continuous frequency.
Modulation in present embodiment is substantially OFDM modulation, has used 128 subcarrier (i.e. N=in the process
128), carrier wave interval delta f=375Hz, effective sub-carrier number are 8 (i.e. M=8), significant character duration T=2.67ms, letter
Number bandwidth f=3k.
The main realization process of OFDM is based on Fourier transformation and inverse transformation.It is operated in this step in inverse Fourier transform
Before further include a pretreatment operation, further includes a post-processing operation after transformation.Specifically:
To a data cell, serioparallel exchange is carried out as unit of a byte, i.e., is divided into the 8bit data of each byte
120 0 one group of data for constituting 128 bit as redundant data are added among this, then include to this group by front and back 4bit
The data of 128 bit carry out inverse fast Fourier transform, obtain frequency domain data, are completed frequency domain to all packet datas
After conversion, then each group of data restored, converts parallel data into serial data flow, i.e., each grouping frequency domain data that will be obtained
The data flow of a whole string is combined into according to original sequence group, to complete OFDM modulation.The 8bit of above-mentioned each byte is
The real data source for constituting effective subcarrier, occupies the transmission time of T=2.67ms in data stream transmission process；It is added
120 0, that is, increase the 0 of 120bit be data in order to prevent frequency aliasing, Δ is constituted in data stream transmission process
The carrier wave interval of f=375Hz, can effective separate data byte.
Preferably, the value of M is 2-64, and the absolute value range of the frequency difference of any two carrier wave is in M carrier wave
86Hz-16kHz。
It is highly preferred that the value of M be 2-16, and in M carrier wave the frequency difference of any two carrier wave absolute value range
For 750Hz-3kHz.
For above-mentioned two preferred embodiment, it is illustrated so that one-channel signal code rate takes 2 for K, M as an example: transmission rate at this time
It may be considered 2K, but with the raising of M, it is desirable to reduce K value is just able to maintain stability, and rate K*M total in this way is not fully just
Than in M.Simultaneously as M increases, computational complexity is consequently increased.
When M takes 2, serioparallel exchange is equivalent to as unit of 2 bit, is divided into each 1bit in front and back, 126 0 are added among this
Having technical effect that for one group of data of 128 bit is constituted, improves transmission rate by about one time than unicast communication, estimation can
To reach 1.2kbps (when taking BPSK to modulate).
It when M takes 16, is equivalent to as unit of two byte 16bit, each 8bit in front and back, it is 112 0 intermediate.Its technical effect
It is, in the poor calculating environment of the computing capabilitys such as mobile device, smooth can runs, and ensure that higher transmission speed
Rate, theory can achieve 4.8kbps.
It when M takes 32, is equivalent to as unit of 4 byte 32bit, each 16bit in front and back, it is 96 0 intermediate.Its technical effect exists
In the transmission rate than the scheme that M takes 2 or 16 is all high, and more stable in voice transmission, is suitable for iphone etc.
The practical scene of sound device better performances, theoretical transmission rate can achieve 9.6kbps.
It when M takes 64, is equivalent to as unit of 8 byte 64bit, each 32bit in front and back, it is 64 0 intermediate.In several schemes
Transmission rate highest, suitable for customizing the hardware device of high-end microphone, theoretical transmission rate can achieve 19.2kbps.
The absolute value range of the frequency difference of any two carrier wave is substantially related with M in M carrier wave.For example, in 3kHz
More than, then take the frequency differential ranges (actual spectrum 3kHz-6kHz) of 3kHz, general mobile phone can smooth reception, at this point, working as M
When=8, minimum interval 375Hz is just obtained.For some high-end handsets, the spectral range of 6-8kHz or so is can to receive
, at this time if M=8, frequency difference maximum absolute value value takes 6kHz, and minimum interval is just 750Hz.16kHz is some spies
The range that the hardware device not customized can achieve.
Difference on the frequency minimum value 86Hz is that M takes 64, value when maximum frequency difference is 5504.
S14, synchronous code is added in data cell.
The synchronous code of 7 OFDM symbols composition is added in the front end of each data grouping, synchronous code is according to certain rule
Rule arrangement, signal when being mainly used for receiving data is synchronous, sign form are as follows:
P=[1,0,1,0, -1,0,1,0]；
- P=[- 1,0, -1,0,1,0, -1,0]；
1=[1,1,1,1,1,1,1,1].
The use of synchronous code, primarily to receiving end is when data demodulation, as data synchronization, channel estimation etc.
Foundation, while also increasing the certain redundancy and robustness of data.
The structure of synchronous code is made of 7 OFDM symbols, and 7 symbols are respectively [1,0,1,0, -1,0,1,0], [1,0,1,
0, -1,0,1,0], [- 1,0, -1,0,1,0, -1,0], [- 1,0, -1,0,1,0, -1,0], [1,0,1,0, -1,0,1,0], [1,
0,1,0, -1,0,1,0], [1,1,1,1,1,1,1,1] constitutes the " sequence of P, P,-P,-P, P, P, 1 ".
In other embodiments, synchronous code be added can also before generating voice signal whenever progress,
The data cell " might not be modulated on M carrier wave to " it by pre-arranged code rule in step as described in this embodiment
Afterwards and before step " cyclic prefix is added ".
Further, data cell includes synchronous code, data length, grouping number, packet numbering or real data.Wherein
The numerical value of data length, grouping number or packet numbering is respectively less than or is equal to 255.
Wherein, synchronous code FCH is mainly used for receiving end to the synchronization of data and channel estimation judgement；One byte length
Data illustrate the length for the data that transmitting terminal should actually be sent；Packet count specifies the total number of packet for sending data；
Packet numbering specifies the packet numbering of notebook data grouping, for illustrating physical location locating for this packet data, for receiving
End carries out arrangement reduction to data；The real data part of the grouping of transmission, data portion save each group of real data
Content.By the organic assembling of above-mentioned grouping, receiving end can effectively demodulate and restore data transmitted by transmitting terminal, and have
There is corresponding error check ability.
Each data cell after grouped includes the data length+1 of+1 byte of synchronous code of 7 OFDM symbol length
Packet numbering+grouping real data part of+1 byte of packet count of byte.Furthermore the parameter being grouped specifically:
Every group of maximum length: 40 OFDM symbols are 40 byte；
Every group of maximum total bit number: 40 × 8=320bit.
The reasons why limiting block length range is that, in the specific implementation process for simplified communication system, do not have
Consider the sampling frequency synchronization and carrier frequency synchronization of ofdm system, therefore the length of data transmission cannot be too long, it otherwise can be by
It adds up in error and causes error code.Data are easy to be interfered and error code in transmission process simultaneously, therefore use grouping transmission.Through
A large amount of actual measurements are crossed, when block length is (20~80) symbol, the efficiency highest of system, other length can also receive,
But at least it is less than 240 symbols, otherwise can be difficult to be properly received because of the influence of error code.Grouping in general communication method
Length is general long or without limitation, and it is unstable to may cause final sound.Present embodiment is by limiting block length
System, has reached reliable and stable laser propagation effect.
S15, cyclic prefix is added in data cell.
The continuous data stream that 128bit is unit can be obtained after the OFDM modulation for completing data, at this time by each 128bit
It reintegrates, rear 32bit duplication therein is added to the front end that 128bit flows, the continuous data stream of 160bit is constituted, completes
The circulation of data realizes the addition of cyclic prefix.
S16, voice signal is generated.
It is walked by this, sound letter in the data flow re-modulation to the frequency band that can be transmitted after above-mentioned coded modulation, will be generated
Number.Its design parameter are as follows: according to sampling thheorem, data stream is sampled using the sample frequency not less than 2 times of data frequency,
In order to which to data sampling, the sample frequency not less than 48kHz preferably can be used, then using the microphone of regular handset and raising
Sound device can receive preferable frequency f=3~7KHz as carrier frequency, and then the data that sampling obtains are multiplied with carrier signal
Frequency band transmission data are obtained, that is, complete the band modulation of data, to obtain the voice data stream for voice transmission.This step
The frequency of voice signal generated in rapid is located at following ranges:
(93.75*0.9*k-93.75*1.1*k) Hz,
(86.13*0.9*k-86.13*1.1*k) Hz,
(78.13*0.9*k-78.13*1.1*k) Hz,
(62.5*0.9*k-62.5*1.1*k) Hz, or
(43.1*0.9*k-43.1*1.1*k) Hz, wherein k=0,1 ..., 255.
When the voice signal generated being enabled to be located above range frequency, it can just be adopted in two common the common of sound pick-up outfit
Sample rate range obtains orthogonality.For example, taking any two in a set of frequencies that can constitute two-by-two just under 48k sample rate
The relationship of friendship.
Inventor has found during selection signal frequency range, the frequency that can be played due to the loudspeaker of general mobile phone
Range is (0~22KHz) signal, and the frequency range that mobile microphone can be recorded is (0~22KHz), the Mike of part mobile phone
The frequency range that wind can be recorded is (0~9KHz) (known mobile phone has millet 1, Nubia mobile phone), in (0~3KHz) frequency
In range, signal is highly susceptible to influence of ambient noise, such as people's one's voice in speech etc..Therefore the frequency range that can be used
For (3KHz~22KHz).Furthermore inventor is by test discovery, and the signal of 16KHz or more is in mobile phone broadcasting and receive process
What is be attenuated is very serious, therefore is not suitable for transmitting data, therefore the frequency range that can be used is (3KHz~16KHz).Such as
Fruit wants compatible all mobile phones, then the frequency range that can be used is (3KHz~9KHz).
In addition, through inventor the study found that the decay formula propagated in air based on sound is it is found that decaying mainly includes
Transmitting decaying and air absorb two parts；Under general room temperature and relative humidities, one timing of transmission range, 22kHz or more
The voice transmission attenuation rate of frequency sharply increases, thus in M carrier wave the absolute value of the frequency difference of any two carrier wave answer it is small
In or equal to 22kHz, it is more than 22kHz that sound wave highest frequency otherwise can be made during carrying out frequency spectrum shift.In view of certain
The presence of ambient noise, to maintain signal-to-noise ratio, 16kHz is more optimistic estimated value；When ambient noise is larger, 3kHz or so tool
There is stronger robustness.
Inventor by a large amount of actual test obtain subcarrier spacing Δ f be (86HZ~750HZ) when, communication efficiency compared with
It is good.When being lower than 86Hz, it is easy to happen spectral interference between each subcarrier, the bit error rate is caused to improve.When being higher than 750Hz, frequency
The utilization rate of spectrum is lower, and transmission code rate is difficult to improve.The value of effective sub-carrier number N can be by signal bandwidth f and subcarrier spacing
Δ f is obtained, N=f/ Δ f.
Further, in step S13, in order to improve code rate, while multiple carrier signal transmission data being used.In order to avoid
The mutual aliasing of intercarrier, chooses mutually orthogonal carrier signal.These mutually orthogonal subcarriers meet following formula:
Wherein Tsym indicates the signal period.The orthogonal frequency that can choose under 48kHz sample frequency has frequency shown in table 1
Rate.Several or whole Frequency points in frequency 1, frequency 2, frequency 3 or frequency 4 can be selected according to actual needs.
The orthogonal frequency (unit Hz) that can be selected when 1 sample frequency 48kHz of table
In another example the orthogonal frequency that can choose under 44.1kHz sample frequency has frequency shown in table 2.It can basis
Actual demand selects several or whole Frequency points in frequency 1, frequency 2, frequency 3 or frequency 4.
The orthogonal frequency (unit Hz) that can be selected when 2 sample frequency 44.1kHz of table
Present embodiment design acoustic communication sending method realize to data it is quick, accurately and efficiently modulation and
It sending, highest can realize the transmission rate of 2.4kbps in the system using BPSK modulation, and in the system using QPSK modulation
In highest transmission rate can reach 4.8kbps.
Referring to Fig. 2, for the structural schematic diagram of acoustic communication sending device described in an embodiment of the present invention；Described device
Module 21, verification setup module 22, modulation module 23, synchronous code module 24,25 harmony of cyclic prefix module are split including data
Sound generation module 26.
The data split module 21 and are used to split data to be sent by preset length condition, obtain several data cells.
The verification setup module 22 is used to that check code to be arranged to data cell.
The modulation module 23 is used to the data cell being modulated to M carrier wave by pre-arranged code rule, M for greater than
Or the positive integer equal to 2, the M carrier wave meet the relationship of pairwise orthogonal, and in M carrier wave any two carrier wave difference on the frequency
The absolute value of value is less than or equal to 22kHz；The coding rule includes phase parameter or range parameter；It specifically includes:
Data cell is converted into one group of sequence of complex numbers by default transformation rule, and presses default selection rule from the plural number sequence
M plural number is chosen in column, and this M plural number is formed into a length with default composition rule with (N-M) a 0 as the data group of N, and
N point inverse Fourier transform is done to the data group；Wherein N > M and N=2i, i is positive integer.
It connects all inverse Fourier transform consequential signals and obtains modulation result signal.
The synchronous code module 24 is for being added synchronous code.
The cyclic prefix module 25 is for being added cyclic prefix.
The sound generation module is for generating voice signal.
The present apparatus realizes that the concrete mode of acoustic communication sending function is as follows:
It is used to split data to be sent by preset length condition firstly, data split module 21, obtains several data cells.
Data split module 21 and select or edit first particular content to be sent, the length of data to be sent are calculated, then according to reality
The setting of system splits data to be sent with the length for being no more than 40 bytes in the application of border, obtains several data sheets
Member.Subsequent data processing will all be carried out respectively as unit of each data cell.In the original length of data to be sent itself
When just having met preset length condition.Data split module 21 and its performed function and can save.
Setup module 22 is verified to be used to that check code to be arranged to a data cell.
Each data cell is marked in verification setup module 22 first, then in the end of data cell with 1bit is single
Position is set to front end data and is grouped corresponding bit.By the way that check code is arranged, redundancy is provided for the data demodulation of receiving end
The foundation of error check.The verification mode includes even-odd check, odd-even difference parity check sum CRC cyclic redundancy check, be can also be
Other can reach the conventional method of data check purpose.
Modulation module 23 is used to the data cell being modulated to M carrier wave by pre-arranged code rule.It specifically includes:
Data cell is converted into one group of sequence of complex numbers by default transformation rule, and presses default selection rule from the plural number sequence
M plural number is chosen in column, and this M plural number is formed into a length with default composition rule with (N-M) a 0 as the data group of N, and
N point inverse Fourier transform is done to the data group；Wherein N > M and N=2i, i is positive integer；
It connects all inverse Fourier transform consequential signals and obtains modulation result signal.
The default transformation rule can be BPSK or QPSK.It converts, then adjusts " 0 " in Serial No. according to BPSK
It is made as " -1 ", " 1 " in Serial No. is modulated to " 1 ", to obtain positive and negative staggered bpsk signal；It is converted according to QPSK,
" 00 " in sequence is then modulated to " -1-i ", " 01 " is modulated to " -1+i ", and " 10 " are modulated to " 1-i ", and " 11 " are modulated to " 1+
I " facilitates the carrier modulation of follow-up data to obtain the QPSK data flow of four phases, provides safeguard for data transmission.
The default selection rule may include choosing the initial position of M plural number from the sequence of complex numbers or choosing to advise
Rule, such as from sequence of complex numbers i1-i10In select 3 plural numbers, can be i1,i2,i3, can be i5,i6,i7, can be i4,i8,
i10, it is also possible to i9,i3,i7。
The default composition rule includes position of (N-M) a 0 in the data group that length is N, such as is somebody's turn to do (N-M)
A 0 is located at the front end for the data group that length is N, positioned at the rear end for the data group that length is N, or the data group for being N positioned at length
Centre.
Preferred default composition rule is that will be somebody's turn to do the centre that (N-M) a 0 is placed in the data group that length is N.For example, working as N=
When 10, M=6,0 number is 4, and according to the preferred composition rule, which is the data group arrangement mode of N are as follows: a1,a2,
a3,0,0,0,0,a4,a5,a6,.Wherein a1-a6For valid data.This rule that preferably constitutes is beneficial in that, practical to grasp
In work, it is maximum positive frequency value and negative frequency value, both ends 0 that the result feature that part fft is converted, which is centre,；And 0 is set
In centre, then treatment effect, which is equivalent to, has taken continuous-L-+L frequency values can after the operation for moving 0-22k frequency range
To obtain a continuous frequency.
The modulation that modulation module 23 is carried out substantially is OFDM modulation, has used 128 subcarrier (i.e. N in the process
=128), carrier wave interval delta f=375Hz, effective sub-carrier number be 8 (i.e. M=8), significant character duration T=2.67ms,
Signal bandwidth f=3k.
The main realization process of OFDM is based on Fourier transformation and inverse transformation.Before carrying out inverse Fourier transform operation
Modulation module 23 also needs to carry out a pretreatment operation, further includes a post-processing operation after transformation.Specifically:
To a data cell, serioparallel exchange is carried out as unit of a byte, i.e., is divided into the 8bit data of each byte
120 0 one group of data for constituting 128 bit as redundant data are added among this, then include to this group by front and back 4bit
The data of 128 bit carry out inverse fast Fourier transform, obtain frequency domain data, are completed frequency domain to all packet datas
After conversion, then each group of data restored, converts parallel data into serial data flow, i.e., each grouping frequency domain data that will be obtained
The data flow of a whole string is combined into according to original sequence group, to complete OFDM modulation.The 8bit of above-mentioned each byte is
The real data source for constituting effective subcarrier, occupies the transmission time of T=2.67ms in data stream transmission process；It is added
120 0, that is, increase the 0 of 120bit be data in order to prevent frequency aliasing, Δ is constituted in data stream transmission process
The carrier wave interval of f=375Hz, can effectively separate data byte.
Preferably, the value of M is 2-64, and the absolute value range of the frequency difference of any two carrier wave is in M carrier wave
86Hz-16kHz。
It is highly preferred that the value of M be 2-16, and in M carrier wave the frequency difference of any two carrier wave absolute value range
For 750Hz-3kHz.
For above-mentioned two preferred embodiment, it is illustrated so that one-channel signal code rate takes 2 for K, M as an example: transmission rate at this time
It may be considered 2K, but with the raising of M, it is desirable to reduce K value is just able to maintain stability, and rate K*M total in this way is not fully just
Than in M.Simultaneously as M increases, computational complexity is consequently increased.
When M takes 2, serioparallel exchange is equivalent to as unit of 2 bit, is divided into each 1bit in front and back, 126 0 are added among this
Having technical effect that for one group of data of 128 bit is constituted, improves transmission rate by about one time than unicast communication, estimation can
To reach 1.2kbps (when taking BPSK to modulate).
It when M takes 16, is equivalent to as unit of two byte 16bit, each 8bit in front and back, it is 112 0 intermediate.Its technical effect
It is, in the poor calculating environment of the computing capabilitys such as mobile device, smooth can runs, and ensure that higher transmission speed
Rate, theory can achieve 4.8kbps.
It when M takes 32, is equivalent to as unit of 4 byte 32bit, each 16bit in front and back, it is 96 0 intermediate.Its technical effect exists
In the transmission rate than the scheme that M takes 2 or 16 is all high, and more stable in voice transmission, is suitable for iphone etc.
The practical scene of sound device better performances, theoretical transmission rate can achieve 9.6kbps.
It when M takes 64, is equivalent to as unit of 8 byte 64bit, each 32bit in front and back, it is 64 0 intermediate.In several schemes
Transmission rate highest, suitable for customizing the hardware device of high-end microphone, theoretical transmission rate can achieve 19.2kbps.
The absolute value range of the frequency difference of any two carrier wave is substantially related with M in M carrier wave.For example, in 3kHz
More than, then take the frequency differential ranges (actual spectrum 3kHz-6kHz) of 3kHz, general mobile phone can smooth reception, at this point, working as M
When=8, minimum interval 375Hz is just obtained.For some high-end handsets, the spectral range of 6-8kHz or so is can to receive
, at this time if M=8, frequency difference maximum absolute value value takes 6kHz, and minimum interval is just 750Hz.16kHz is some spies
The range that the hardware device not customized can achieve.
Difference on the frequency minimum value 86Hz is that M takes 64, value when maximum frequency difference is 5504.
Synchronous code module 24 in data cell for being added synchronous code.
The synchronous code of 7 OFDM symbols composition is added in the front end of each data grouping, synchronous code is according to certain rule
Rule arrangement, signal when being mainly used for receiving data is synchronous, sign form are as follows:
P=[1,0,1,0, -1,0,1,0]；
- P=[- 1,0, -1,0,1,0, -1,0]；
1=[1,1,1,1,1,1,1,1].
The use of synchronous code, primarily to receiving end is when data demodulation, as data synchronization, channel estimation etc.
Foundation, while also increasing the certain redundancy and robustness of data.
The structure of synchronous code is made of 7 OFDM symbols, and 7 symbols are respectively [1,0,1,0, -1,0,1,0], [1,0,1,
0, -1,0,1,0], [- 1,0, -1,0,1,0, -1,0], [- 1,0, -1,0,1,0, -1,0], [1,0,1,0, -1,0,1,0], [1,
0,1,0, -1,0,1,0], [1,1,1,1,1,1,1,1] constitutes the " sequence of P, P,-P,-P, P, P, 1 ".
Further, data cell includes synchronous code, data length, grouping number, packet numbering or real data.Wherein
The numerical value of data length, grouping number or packet numbering is respectively less than or is equal to 255.
Wherein, synchronous code FCH is mainly used for receiving end to the synchronization of data and channel estimation judgement；One byte length
Data illustrate the length for the data that transmitting terminal should actually be sent；Packet count specifies the total number of packet for sending data；
Packet numbering specifies the packet numbering of notebook data grouping, for illustrating physical location locating for this packet data, for receiving
End carries out arrangement reduction to data；The real data part of the grouping of transmission, data portion save each group of real data
Content.By the organic assembling of above-mentioned grouping, receiving end can effectively demodulate and restore data transmitted by transmitting terminal, and have
There is corresponding error check ability.
Each data cell after grouped includes the data length+1 of+1 byte of synchronous code of 7 OFDM symbol length
Packet numbering+grouping real data part of+1 byte of packet count of byte.Furthermore the parameter being grouped specifically:
Every group of maximum length: 40 OFDM symbols are 40 byte；
Every group of maximum total bit number: 40 × 8=320bit.
The reasons why limiting block length range is that, in the specific implementation process for simplified communication system, do not have
Consider the sampling frequency synchronization and carrier frequency synchronization of ofdm system, therefore the length of data transmission cannot be too long, it otherwise can be by
It adds up in error and causes error code.Data are easy to be interfered and error code in transmission process simultaneously, therefore use grouping transmission.Through
A large amount of actual measurements are crossed, when block length is (20~80) symbol, the efficiency highest of system, other length can also receive,
But at least it is less than 240 symbols, otherwise can be difficult to be properly received because of the influence of error code.Grouping in general communication method
Length is general long or without limitation, and it is unstable to may cause final sound.Present embodiment is by limiting block length
System, has reached reliable and stable laser propagation effect.
OFDM modulation module 25 is used to carry out OFDM modulation to data cell.
In the modulated process of OFDM modulation module 25,128 subcarriers are used, carrier wave interval delta f=375Hz has
Imitating sub-carrier number is 8, significant character duration T=2.67ms, signal bandwidth f=3k.
The main realization process of OFDM is based on Fourier transformation and inverse transformation.In fact, OFDM modulation module 25 is in Fu
In further include a pretreatment operation before leaf Transform operations, further include a post-processing operation after transformation.Specifically:
OFDM modulation module 25 carries out serioparallel exchange to a data cell as unit of a byte, i.e., by each byte
8bit data are divided into front and back 4bit, 120 0 one group of data that 128 bit are constituted as redundant data are added among this, so
Inverse fast Fourier transform is carried out comprising the data of 128 bit to this group afterwards, frequency domain data is obtained, to all packet datas
After being completed frequency domain conversion, then each group of data restored, converts parallel data into serial data flow, i.e., it is each by what is obtained
Grouping frequency domain data is combined into the data flow of a whole string according to original sequence group, to complete OFDM modulation.Above-mentioned each word
The 8bit of section is the real data source for constituting effective subcarrier, occupies T=2.67ms's in data stream transmission process
Transmission time；Be added 120 0, that is, increase the 0 of 120bit be data in order to prevent frequency aliasing, in data stream transmitting
The carrier wave interval of Δ f=375Hz is constituted in the process, it can effective separate data byte.
Cyclic prefix module 25 is for being added cyclic prefix.
The continuous data stream that 128bit is unit can be obtained after the OFDM modulation for completing data, at this time cyclic prefix module
26 reintegrate each 128bit, and rear 32bit duplication therein is added to the front end that 128bit flows, constitutes the company of 160bit
Continuous data flow, completes the circulation of data, that is, realizes the addition of cyclic prefix.
Sound generation module 26 is for generating voice signal.
Specifically, it will pass through in treated data flow re-modulation to the frequency band that can be transmitted and generate sound letter
Number, the design parameter of processing are as follows: according to sampling thheorem, data are flowed into using the sample frequency not less than 2 times of data frequency
Then row sampling uses the wheat of regular handset in order to which to data sampling, the sample frequency not less than 48kHz preferably can be used
Gram wind and loudspeaker are subjected to preferable frequency f=3~7KHz as carrier frequency, the data and carrier wave for then obtaining sampling
Signal multiplication obtains frequency band transmission data, that is, completes the band modulation of data, to obtain the audio number for voice transmission
According to stream.The frequency of voice signal generated is located at following ranges:
(93.75*0.9*k-93.75*1.1*k) Hz,
(86.13*0.9*k-86.13*1.1*k) Hz,
(78.13*0.9*k-78.13*1.1*k) Hz,
(62.5*0.9*k-62.5*1.1*k) Hz, or
(43.1*0.9*k-43.1*1.1*k) Hz, wherein k=0,1 ..., 255.
When the voice signal generated being enabled to be located above range frequency, it can just be adopted in two common the common of sound pick-up outfit
Sample rate range obtains orthogonality.For example, taking any two in a set of frequencies that can constitute two-by-two just under 48k sample rate
The relationship of friendship.
Inventor has found during selection signal frequency range, the frequency that can be played due to the loudspeaker of general mobile phone
Range is (0~22KHz) signal, and the frequency range that mobile microphone can be recorded is (0~22KHz), the Mike of part mobile phone
The frequency range that wind can be recorded is (0~9KHz) (known mobile phone has millet 1, Nubia mobile phone), in (0~3KHz) frequency
In range, signal is highly susceptible to influence of ambient noise, such as people's one's voice in speech etc..Therefore the frequency range that can be used
For (3KHz~22KHz).Furthermore inventor is by test discovery, and the signal of 16KHz or more is in mobile phone broadcasting and receive process
What is be attenuated is very serious, therefore is not suitable for transmitting data, therefore the frequency range that can be used is (3KHz~16KHz).Such as
Fruit wants compatible all mobile phones, then the frequency range that can be used is (3KHz~9KHz).
In addition, through inventor the study found that the decay formula propagated in air based on sound is it is found that decaying mainly includes
Transmitting decaying and air absorb two parts；Under general room temperature and relative humidities, one timing of transmission range, 22kHz or more
The voice transmission attenuation rate of frequency sharply increases, thus in M carrier wave the absolute value of the frequency difference of any two carrier wave answer it is small
In or equal to 22kHz, it is more than 22kHz that sound wave highest frequency otherwise can be made during carrying out frequency spectrum shift.In view of certain
The presence of ambient noise, to maintain signal-to-noise ratio, 16kHz is more optimistic estimated value；When ambient noise is larger, 3kHz or so tool
There is stronger robustness.
Inventor by a large amount of actual test obtain subcarrier spacing Δ f be (86HZ~750HZ) when, communication efficiency compared with
It is good.When being lower than 86Hz, it is easy to happen spectral interference between each subcarrier, the bit error rate is caused to improve.When being higher than 750Hz, frequency
The utilization rate of spectrum is lower, and transmission code rate is difficult to improve.The value of effective sub-carrier number N can be by signal bandwidth f and subcarrier spacing
Δ f is obtained, N=f/ Δ f.
Further, modulation module 23 is in order to improve code rate, while using multiple carrier signal transmission data.In order to avoid
The mutual aliasing of intercarrier, chooses mutually orthogonal carrier signal.These mutually orthogonal subcarriers meet following formula:
Wherein Tsym indicates the signal period.The orthogonal frequency that can choose under 48kHz sample frequency has frequency shown in table 1
Rate.Several or whole Frequency points in frequency 1, frequency 2, frequency 3 or frequency 4 can be selected according to actual needs.
In another example the orthogonal frequency that can choose under 44.1kHz sample frequency has frequency shown in table 2.It can basis
Actual demand selects several or whole Frequency points in frequency 1, frequency 2, frequency 3 or frequency 4.
Present embodiment design acoustic communication sending device realize to data it is quick, accurately and efficiently modulation and
It sending, highest can realize the transmission rate of 2.4kbps in the system using BPSK modulation, and in the system using QPSK modulation
In highest transmission rate can reach 4.8kbps.
It should be noted that, in this document, relational terms such as first and second and the like are used merely to a reality
Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation
In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to
Non-exclusive inclusion, so that the process, method, article or the terminal device that include a series of elements not only include those
Element, but also including other elements that are not explicitly listed, or further include for this process, method, article or end
The intrinsic element of end equipment.In the absence of more restrictions, being limited by sentence " including ... " or " including ... "
Element, it is not excluded that there is also other elements in process, method, article or the terminal device for including the element.This
Outside, herein, " being greater than ", " being less than ", " being more than " etc. are interpreted as not including this number；" more than ", " following ", " within " etc. understand
Being includes this number.
It should be understood by those skilled in the art that, the various embodiments described above can provide as method, apparatus or computer program production
Product.Complete hardware embodiment, complete software embodiment or embodiment combining software and hardware aspects can be used in these embodiments
Form.The all or part of the steps in method that the various embodiments described above are related to can be instructed by program relevant hardware come
It completes, the program can store in the storage medium that computer equipment can be read, for executing the various embodiments described above side
All or part of the steps described in method.The computer equipment, including but not limited to: personal computer, server, general-purpose computations
It is machine, special purpose computer, the network equipment, embedded device, programmable device, intelligent mobile terminal, smart home device, wearable
Smart machine, vehicle intelligent equipment etc.；The storage medium, including but not limited to: RAM, ROM, magnetic disk, tape, CD, sudden strain of a muscle
It deposits, USB flash disk, mobile hard disk, storage card, memory stick, webserver storage, network cloud storage etc..
The various embodiments described above are referring to the method according to embodiment, equipment (system) and computer program product
Flowchart and/or the block diagram describes.It should be understood that can be realized by computer program instructions every in flowchart and/or the block diagram
The combination of process and/or box in one process and/or box and flowchart and/or the block diagram.It can provide these computers
Program instruction generates a machine to the processor of computer equipment, so that the finger executed by the processor of computer equipment
It enables and generates to specify in one or more flows of the flowchart and/or one or more blocks of the block diagram
The device of function.
These computer program instructions, which may also be stored in, to be able to guide computer equipment computer operate in a specific manner and sets
In standby readable memory, so that the instruction being stored in the computer equipment readable memory generates the manufacture including command device
Product, command device realization refer in one or more flows of the flowchart and/or one or more blocks of the block diagram
Fixed function.
These computer program instructions can also be loaded into computer equipment, so that executing on a computing device a series of
Operating procedure is to generate computer implemented processing, so that the instruction executed on a computing device is provided for realizing in process
The step of function of being specified in figure one process or multiple processes and/or block diagrams one box or multiple boxes.
Although the various embodiments described above are described, once a person skilled in the art knows basic wounds
The property made concept, then additional changes and modifications can be made to these embodiments, so the above description is only an embodiment of the present invention,
It is not intended to limit scope of patent protection of the invention, it is all to utilize equivalent structure made by description of the invention and accompanying drawing content
Or equivalent process transformation, being applied directly or indirectly in other relevant technical fields, similarly includes in patent of the invention
Within protection scope.
Claims (10)
1. a kind of acoustic communication sending method, comprising steps of
One data cell is handled as follows:
Check code is set；
The data cell is modulated on M carrier wave by pre-arranged code rule, is specifically included:
Data cell is converted into one group of sequence of complex numbers by default transformation rule, the default transformation rule is BPSK, and by pre-
If selection rule chooses M plural number from the sequence of complex numbers, and this M plural number is formed with (N-M) a 0 with default composition rule
One length is the data group of N, and the default composition rule includes position of (N-M) a 0 in the data group that length is N,
And N point inverse Fourier transform is done to the data group；Wherein N > M and N=2i, i is positive integer；
It connects all inverse Fourier transform consequential signals and obtains modulation result signal；Wherein, M is the positive integer more than or equal to 2,
The M carrier wave meets the relationship of pairwise orthogonal, and in M carrier wave the absolute value of the frequency difference of any two carrier wave be less than or
Equal to 22kHz；The coding rule includes phase parameter or range parameter；
Synchronous code is added；
Cyclic prefix is added；
Generate voice signal.
2. in acoustic communication sending method as described in claim 1, the data cell include data length, grouping number or
Packet numbering, and the numerical value of data length, grouping number or packet numbering is respectively less than or is equal to 255.
3. in acoustic communication sending method as described in claim 1, the value of M is 2-64, and any two carry in M carrier wave
The absolute value range of the frequency difference of wave is 86Hz-16kHz.
4. in acoustic communication sending method as described in claim 1, the value of M is 2-16, and any two carry in M carrier wave
The absolute value range of the frequency difference of wave is 750Hz-3kHz.
5. in acoustic communication sending method as described in claim 1, step " generating voice signal " voice signal generated
Frequency be located at following ranges:
(93.75*0.9*k-93.75*1.1*k) Hz,
(86.13*0.9*k-86.13*1.1*k) Hz,
(78.13*0.9*k-78.13*1.1*k) Hz,
(62.5*0.9*k-62.5*1.1*k) Hz, or
(43.1*0.9*k-43.1*1.1*k) Hz, wherein k=0,1 ..., 255.
6. a kind of acoustic communication sending device, including verification setup module, modulation module, synchronous code module, cyclic prefix module
With sound generation module；
The verification setup module is used to that check code to be arranged to data cell；
The modulation module is used to the data cell being modulated to M carrier wave by pre-arranged code rule, specifically includes: will count
One group of sequence of complex numbers is converted to by default transformation rule according to unit, the default transformation rule is BPSK, and chooses rule by default
M plural number is then chosen from the sequence of complex numbers, and this M plural number is formed into a length with (N-M) a 0 with default composition rule and is
The data group of N, and N point inverse Fourier transform is done to the data group, the default composition rule includes (N-M) a 0 in length
Degree is the position in the data group of N；Wherein N > M and N=2i, i is positive integer；All inverse Fourier transform consequential signals are connected to obtain
To modulation result signal；Wherein M is the positive integer more than or equal to 2, and the M carrier wave meets the relationship of pairwise orthogonal, and M
The absolute value of the frequency difference of any two carrier wave is less than or equal to 22kHz in carrier wave；The coding rule includes phase parameter
Or range parameter；
The synchronous code module is for being added synchronous code；
The cyclic prefix module is for being added cyclic prefix；
The sound generation module is for generating voice signal.
7. in acoustic communication sending device as claimed in claim 6, the data cell include data length, grouping number or
Packet numbering, and the numerical value of data length, grouping number or packet numbering is respectively less than or is equal to 255.
8. in acoustic communication sending device as claimed in claim 6, the value of M is 2-64, and any two carry in M carrier wave
The absolute value range of the frequency difference of wave is 86Hz-16kHz.
9. in acoustic communication sending device as claimed in claim 6, the value of M is 2-16, and any two carry in M carrier wave
The absolute value range of the frequency difference of wave is 750Hz-3kHz.
10. in acoustic communication sending device as claimed in claim 6, the frequency of sound generation module voice signal generated
Positioned at following ranges:
(93.75*0.9*k-93.75*1.1*k) Hz,
(86.13*0.9*k-86.13*1.1*k) Hz,
(78.13*0.9*k-78.13*1.1*k) Hz,
(62.5*0.9*k-62.5*1.1*k) Hz, or
(43.1*0.9*k-43.1*1.1*k) Hz, wherein k=0,1 ..., 255.
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| CN107437967A (en) * | 2017-06-08 | 2017-12-05 | 深圳市迈岭信息技术有限公司 | Data transmission method based on sound wave, send equipment and receiving device |
| US10826623B2 (en) * | 2017-12-19 | 2020-11-03 | Lisnr, Inc. | Phase shift keyed signaling tone |
| CN111313979B (en) * | 2020-01-21 | 2021-09-17 | 北京达佳互联信息技术有限公司 | Data transmission method and device, electronic equipment and storage medium |
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