CN1866941A - Modulation/demodulation process and apparatus for transmitting data with PSTN channel using GSM voice channel - Google Patents
Modulation/demodulation process and apparatus for transmitting data with PSTN channel using GSM voice channel Download PDFInfo
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Abstract
The invention relates to a modulate/demodulate method for using GSM voice channel and PSTN channel to transmit data, and relative modulator/demodulator. Wherein, said method comprises: modulating the transmitted data bit flow into similar voice signal and demodulating received said signal into data bit flow; said device comprises a sending device and a receiving device; the sending device comprises a data input interface, a data distributor, a sub-band channel coder, a sub-band modulator, a signal synthesizer, a signal output interface; said receiving device comprises an analogue signal input interface, a sub-band filter, a sub-band demodulator, a sub-band channel demodulator, a data synthesizer, and a data output interface. The invention can transmit data between GSM voice channel and PSTN channel, without changing the mechanism and protocol of GSM network.
Description
Technical field
The present invention relates to a kind of modulation-demo-demodulation method and modulation-demodulation device thereof of voice communication technical field transmission data, particularly a kind of modulation-demo-demodulation method and modulation-demodulation device thereof with GSM voice channel and PSTN channel transmission data.
Background technology
The technology transfer voice signal that gsm mobile communication system adopts frequency division multiple access and time division multiple access to combine is present the most widely used voice mobile communication system.Yet, also become one of problem demanding prompt solution at the gsm mobile communication system transmitting data along with extensively carrying out of data communication.
The solution that is widely adopted at present be gsm system by GPRS network, according to data exchange agreement, with data-signal in the packet mode by GPRS network, use data channel to be user's transmission of data signals.But because the procotol that GPRS adopts is different with GSM, increased the complexity of communication system, the packet exchange agreement of GPRS employing simultaneously exists easily blocks up, postpones defectives such as bigger, bad to some data signals transmitted adaptability that need to link up in real time.
In order to reduce the system complex degree, people attempt to utilize GSM voice channel transmission data under the prerequisite that does not change GSM network existing protocol.A kind of trial scheme is directly to install the common modulation demodulated equipment additional to treat and transmit data and modulate on the GSM voice channel, with baseband signal after the modulation that obtains by the transmission of GSM voice channel.But the stability of this scheme and percent reduction all do not reach requirement.This be because:
The GSM channel is the digitize voice channel, to carry out doing transmission again after the voice compression coding to the voice signal that receives, when direct use common modulation demodulated equipment transmits data, the signal that the GSM voice channel obtains after the common modulation demodulated equipment is modulated data still is used as voice and is treated, with RPE-LTP or EFR algorithm it is carried out encoding and decoding, and the good simulating nature voice of the signal that the common modulation demodulated equipment obtains after data are modulated.Its reason is as follows:
1.GSM only being suitable for parameter, RPE-LTP that uses or EFR technology change slower natural-sounding.People's fundamental tone generally arrives the hundreds of hertz tens., the rate of change of formant envelope is lower.And the speed of common modulation demodulator is all more than 1000BPS.The RPE-LTP of low speed and EFR tracking velocity are unable to catch up with common modulation demodulator baseband signal rate of change.
2.RPE-LTP or the EFR technology only carries out strict coupling to the voice low frequency part, and the voice HFS is only generally simulated, so require the carrier frequency of modulator-demodulator can not be too high.And the carrier frequency of common modulation demodulator is all higher, and RPE-LTP or EFR technology can not be fine to its simulation.
Therefore adopt the common modulation demodulator to transmit data incompatibility GSM channel, can not reliable transmitting data.
Summary of the invention
In view of the foregoing, the objective of the invention is in order to solve under the prerequisite that does not change existing system of GSM or PSTN network and agreement, a kind of modulation-demo-demodulation method and modulation-demodulation device thereof are provided, the data conversion that will transmit is the speech-like signal of similar natural-sounding, utilizes the transmission data that the GSM voice channel is stable, link up.
The technical solution adopted in the present invention is: utilize the modulation-demo-demodulation method of GSM voice channel and PSTN channel transmission data, this method comprises following two programs:
Program one. the data bit flow that will transmit is modulated to speech-like signal:
The bandwidth of GSM or PSTN net voice channel is divided into a plurality of subbands; Give each subband the total data rate that will transmit by the pro rate of setting, obtain subband data; Data to each subband are carried out the subband carrier modulation respectively, form class voice subband signal; Class voice subband signal is synthetic, forms speech-like signal;
Wherein, subband carrier modulation process comprises following five steps:
(1) chnnel coding;
(2) generate I road, Q road signal;
(3) I road, Q road signal are carried out interpolation respectively;
(4) the I road after the interpolation, Q road signal are carried out molding filtration;
(5) carrier modulation obtains class voice subband signal;
Class voice subband signal synthesis step is: make the algebraical sum of each modulated class voice subband signal, obtain speech-like signal;
Program two. the speech-like signal that receives is demodulated into data bit flow:
With the speech-like signal that the receives identical a plurality of band pass filters of subband number by with modulation the time, obtain and the class voice subband signal of same number when modulating; Respectively each class voice subband signal is carried out demodulation, form subband data; Subband data is comprehensive, obtains total data bit flow;
Wherein, class voice subband signal demodulating process may further comprise the steps:
(1) lock-out pulse extracts: step comprises carries out rectification to class voice subband signal, bandpass filtering, and amplification obtains lock-out pulse;
(2) solve subband signal: step comprises uses cos (ω .n.T) and sin (ω .n.T) to multiply by subband signal respectively; Low-pass filtering obtains I road, Q road signal;
(3) respectively I road, Q road signal sampling are obtained digital signal with lock-out pulse;
(4) digital signal is done equilibrium, obtain subband data with error correcting code;
(5) subband data carries out channel-decoding respectively, and the back subband data obtains decoding;
The comprehensive step of subband data is: the data allocations ratio carries out comprehensively demodulating the total data bit stream to the back subband data of decoding during in modulation.
With the present invention with the modulation-demodulation device that the modulation-demo-demodulation method of GSM voice channel and PSTN channel transmission data adapts, comprise dispensing device and receiving system.
Dispensing device comprises:
Data Input Interface is used to receive input traffic;
Data distributor is used for the input data are divided into some subband datas;
The sub-band channel encoder is made up of interleaving coder, CRC check device, encoder, is used to finish the chnnel coding to subband data;
The subband modulator is used for subband data is modulated, and it is changed to class voice subband signal;
Signal synthesizer is done the algebraical sum of class voice subband signal, obtains speech-like signal;
Analog signal output interface is used for the output class voice signal.
Receiving system comprises:
Analog input interface is used to import speech-like signal;
Sub-filter passes through one group of band pass filter with the speech-like signal of importing, and obtains class voice subband signal;
The subband demodulator is used for the demodulation of class voice subband signal, is reduced into the subband data of band error correcting code;
The sub-band channel decoder is made up of channel decoder, CRC check device, interleaved decoder, is used to finish the subband data channel-decoding, obtains subband data;
Data combiner is used to finish synthetic to subband data, obtains output stream;
Data output interface is used for output stream.
The present invention adopts and divides a plurality of low carrier frequency subbands and carry out the modulation-demo-demodulation method that lower rate transmissions combines, use special being used to realize the modulation-demodulation device of this method, can reach under the prerequisite that does not change GSM network system and agreement, make data in GSM voice channel and real-time mutually, the reliable transmission of PSTN interchannel.
The present invention adapts to the characteristics of GSM voice channel, according to method of the present invention, be fit to GSM with RPE-LTP or EFR technology with the speech-like signal of modulating device of the present invention modulation output, can ensure the quality of products through data recovered signal after the demodulating equipment demodulation of the present invention at receiving terminal, satisfy user's instructions for use.
Description of drawings
The invention will be further described below in conjunction with embodiment and accompanying drawing thereof.
Fig. 1 is the block diagram of modulation-demo-demodulation method program one of the present invention.
Fig. 2 is the block diagram of modulation-demo-demodulation method program two of the present invention.
Fig. 3 is the structured flowchart of modulation-demodulation device dispensing device of the present invention.
Fig. 4 is the structured flowchart of modulation-demodulation device receiving system of the present invention.
Among the figure: 1. Data Input Interface, 2. data distributor, 3. sub-band channel encoder, 4. subband modulator, 5. signal synthesizer, 6. signal output interface, 7. analog input interface, 8. sub-filter, 9. subband demodulator, 10. sub-band channel decoder, 11. data combiners, 12. data output interfaces.
Embodiment
The embodiment of the invention comprises following two programs with the modulation-demo-demodulation method of GSM voice channel and PSTN channel transmission data:
Flow process with reference to Fig. 1 can be seen:
Program one. the data bit flow that will transmit is modulated to speech-like signal:
1. the bandwidth with GSM or PSTN net voice channel is divided into a plurality of subbands;
2. give each subband the total data rate that will transmit by the pro rate of setting, obtain subband data; The ratio of this setting comprises uniform distribution, non-homogeneous distribution and their combination.The number of sub-bands that voice channel is divided is at least one subband, and total bandwidth is 2800Hz, and frequency range is that 200Hz is to 3000Hz; Subband speed is no more than 800bps, and total speed is no more than 4800bps.
3. the subband carrier modulation forms class voice subband signal;
4. class voice subband signal is synthetic, forms speech-like signal.
Wherein, subband carrier modulation process comprises following step:
(1) chnnel coding;
(2) generate I road, Q road signal;
(3) I road, Q road signal are carried out interpolation respectively, form the signal of 8000 sampling points of per second;
(4) the I road after the interpolation, Q road signal are passed through molding filtration respectively;
(5) carrier modulation; I road, Q road signal are modulated into class voice subband signal as follows:
Formula: cos (ω .n.T+ θ j)=cos θ j.cos (ω .n.T)-sin θ j.sin (ω .n.T)
Wherein cos θ j is an I road signal, and sin θ j is a Q road signal;
Class voice subband signal synthesis step is: make the algebraical sum of each class voice subband signal, obtain total speech-like signal.
Flow process with reference to Fig. 2 can be seen:
Program two. speech-like signal is demodulated to data bit flow:
With speech-like signal by with the identical a plurality of band pass filters of when modulation subband number, obtain and the class voice subband signal of same number when modulating; Respectively each class voice subband signal is carried out the subband demodulation, form subband data; Subband data is comprehensive, obtains total data flow.
The subband demodulating process may further comprise the steps:
(1) lock-out pulse extracts, and step comprises carries out rectification to class voice subband signal, is 200Hz by a centre frequency again, and bandwidth is the band pass filter of 10Hz, obtains lock-out pulse through amplifying amplitude limit;
(2) solve subband signal, step comprises uses cos (ω .n.T) and sin (ω .n.T) to multiply by class voice subband signal respectively; Low-pass filtering obtains I road, Q road signal;
(3) lock-out pulse that obtains with the step (1) of demodulating process in the program two is sampled respectively to I road, Q road signal, obtains the digital signal on I road, Q road;
(4) digital signal is done equilibrium, obtain subband data with error correcting code;
(5) each subband data is carried out channel-decoding respectively, obtain subband data;
The comprehensive step of subband is: the data allocations ratio carries out comprehensively demodulating the total data bit stream to the back subband data of decoding during in modulation.
Subband modulation-demo-demodulation method described in program one and the program two comprises one of modulation-demo-demodulation methods such as ASK, FSK, PSK, QPSK or its combination at least.
In the present embodiment, the bandwidth of voice channel is divided into 2 subbands, the total data rate that transmit also is equally divided into 2 parts, give a subband for every part.Each subband speed is 800bps, and total speed is 1600bps; Subband modulation-demo-demodulation method described in its program one and the program two is QPSK; Its program one and program two described subband modulation equalization methods are skilled equilibrium.
An alternative embodiment of the invention is divided into n subband with the bandwidth of voice channel, and n equals 3～6 natural number; The total data rate that will transmit in its program one is given each subband by the pro rate of non-homogeneous distribution; The step (4) of demodulating process in step of modulated process (4) and the program two in the program one, the equalization methods of employing is a blind equalization; Other each steps are identical with a last embodiment.
Fig. 3 provides the embodiment of the present invention with the modulation-demodulation device of GSM voice channel and PSTN channel transmission data, and this device comprises dispensing device and receiving system.Wherein, dispensing device comprises:
Data Input Interface 1 is used to receive input traffic;
Data distributor 2 is used for the input data are divided into some subband datas;
Receiving system comprises:
Sub-filter 8 passes through one group of band pass filter with the speech-like signal of importing, and obtains class voice subband signal;
The present invention's modulation-demodulation device of GSM voice channel and PSTN channel transmission data, wherein the quantity of sub-band channel encoder 3, subband modulator 4, sub-filter 8, subband demodulator 9, sub-band channel decoder 10 is respectively 1～6.In the present embodiment, the quantity of sub-band channel encoder 3, subband modulator 4, sub-filter 8, subband demodulator 9, sub-band channel decoder 10 is 2.
Dispensing device in the present embodiment, the output of Data Input Interface 1 connects the input of data distributor 2, each output of data distributor 2 connects the input of each sub-band channel encoder 3 respectively, the output of each sub-band channel encoder 3 connects the input of each subband modulator 4 respectively, each input of signal synthesizer 5 connects the output of each subband modulator 4 respectively, and the output of signal synthesizer 5 connects the input of signal output interface 6;
Receiving system in the present embodiment, the output of analog input interface 7 connects the input of each sub-filter 8 respectively, the output of each sub-filter 8 connects the input of each subband demodulator 9 respectively, the output of subband demodulator 9 connects the input of each sub-band channel decoder 10, the input of data combiner 11 connects the output of each sub-band channel decoder 10 respectively, and the output of data combiner 10 connects the input of data output interface 12.
The present invention is a full-duplex communication device with the modulation-demodulation device of GSM voice channel or PSTN channel transmission data.
According to method of the present invention, the data of modulating with modulating device of the present invention can reach under the prerequisite that does not change GSM network system and agreement, make data in GSM voice channel and real-time mutually, the reliable transmission of PSTN interchannel.This modulation-demodulation device is fit to REP-LTP, the frequency response of EFR codec, in subband number, baud rate, carrier spacing etc. simulation natural-sounding harmonic structure is set, and obtains good transmission quality.
Claims (10)
1. modulation-demo-demodulation method with GSM voice channel and PSTN channel transmission data, it is characterized in that: this method comprises following two programs:
Program one. the data bit flow that will transmit is modulated to speech-like signal:
The bandwidth of GSM or PSTN net voice channel is divided into a plurality of subbands; Give each subband the total data rate that will transmit by the pro rate of setting, obtain subband data; Data to each subband are carried out the subband carrier modulation respectively, form class voice subband signal; Class voice subband signal is synthetic, forms speech-like signal;
Wherein, subband carrier modulation process comprises following five steps:
(1) chnnel coding;
(2) generate I road, Q road signal;
(3) I road, Q road signal are carried out interpolation respectively;
(4) the I road after the interpolation, Q road signal are carried out molding filtration;
(5) carrier modulation obtains class voice subband signal;
Class voice subband signal synthesis step is: make the algebraical sum of each modulated class voice subband signal, obtain speech-like signal;
Program two. the speech-like signal that receives is demodulated into data bit flow:
With the speech-like signal that the receives identical a plurality of band pass filters of subband number by with modulation the time, obtain and the class voice subband signal of same number when modulating; Respectively each class voice subband signal is carried out demodulation, form subband data; Subband data is comprehensive, obtains total data bit flow;
Wherein, class voice subband signal demodulating process may further comprise the steps:
(1) lock-out pulse extracts: step comprises carries out rectification to class voice subband signal, and bandpass filtering obtains lock-out pulse;
(2) solve subband signal: step comprises uses cos (ω .n.T) and sin (ω .n.T) to multiply by subband signal respectively; Low-pass filtering obtains I road, Q road signal;
(3) respectively I road, Q road signal sampling are obtained digital signal with lock-out pulse;
(4) digital signal is done equilibrium, obtain subband data with error correcting code;
(5) channel-decoding, the back subband data obtains decoding;
The comprehensive step of subband data is: the data allocations ratio carries out comprehensively demodulating the total data bit stream to the back subband data of decoding during in modulation.
2. the modulation-demo-demodulation method with GSM voice channel and PSTN channel transmission data according to claim 1 is characterized in that: the speed of program one and program two described total data comprises to the pro rate method in each subband by the pro rate of setting: uniform distribution, non-homogeneous distribution and their combination.
3. the modulation-demo-demodulation method with GSM voice channel and PSTN channel transmission data according to claim 1, it is characterized in that: program one and program two described sub-band division quantity are at least one subband, total bandwidth is 2800Hz, and frequency range is that 200Hz is to 3000Hz.
4. the modulation-demo-demodulation method with GSM voice channel and PSTN channel transmission data according to claim 1, it is characterized in that: program one and program two described subband speed are no more than 800bps, and total speed is no more than 4800bps.
5. the modulation-demo-demodulation method with GSM voice channel and PSTN channel transmission data according to claim 1, it is characterized in that: program one and program two described subband modulation-demo-demodulation methods comprise one of ASK, FSK, PSK, QPSK or its combination at least.
6. the modulation-demo-demodulation method with GSM voice channel and PSTN channel transmission data according to claim 1, it is characterized in that: described subband modulation equalization methods comprises skilled equilibrium and blind equalization.
7. the modulation-demodulation device with GSM voice channel and PSTN channel transmission data comprises dispensing device and receiving system, it is characterized in that:
Described dispensing device comprises:
Data Input Interface is used to receive input traffic;
Data distributor is used for the input data are divided into some subband datas;
The sub-band channel encoder is made up of interleaving coder, CRC check device, encoder, is used to finish the chnnel coding to subband data;
The subband modulator is used for subband data is modulated, and is converted into class voice subband signal;
Signal synthesizer is done the algebraical sum of class voice subband signal, obtains speech-like signal;
Signal output interface is used for the output class voice signal;
Described receiving system comprises:
Analog input interface is used to import speech-like signal;
Sub-filter passes through one group of band pass filter with the speech-like signal of importing, and obtains class voice subband signal;
The subband demodulator is used for the demodulation of class voice subband signal, is reduced into the subband data of band error correcting code;
The sub-band channel decoder is made up of decoder, CRC check device, interleaved decoder, is used to finish the subband data channel-decoding, obtains subband data;
Data combiner is used to finish synthetic to subband data, obtains output stream;
Data output interface is used for output stream.
8. the modulation-demodulation device with GSM voice channel and PSTN channel transmission data according to claim 7, it is characterized in that: the quantity of described sub-band channel encoder, subband modulator, sub-filter, subband demodulator, sub-band channel decoder is respectively 1～6.
9. according to claim 7 and 8 described modulation-demodulation devices, it is characterized in that with GSM voice channel and PSTN channel transmission data:
In the described dispensing device, the output of Data Input Interface connects the input of data distributor, each output of data distributor connects the input of each sub-band channel encoder respectively, the output of each sub-band channel encoder connects the input of each subband modulator respectively, each input of signal synthesizer connects the output of each subband modulator respectively, and the output of signal synthesizer connects the input of signal output interface;
In the described receiving system, the output of analog input interface connects the input of each sub-filter respectively, the output of each sub-filter connects the input of each subband demodulator respectively, the output of subband demodulator connects the input of each sub-band channel decoder, the input of data combiner connects the output of each sub-band channel decoder respectively, and the output of data combiner connects the input of data output interface.
10. according to the described modulation-demodulation device with GSM voice channel and PSTN channel transmission data of claim 7 to 9, it is characterized in that: described modulation-demodulation device is a full-duplex communication device.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101631327B (en) * | 2009-08-04 | 2012-08-08 | 华为技术有限公司 | Method for sending and receiving microwave business data, device thereof and transceiver system |
| CN102737637A (en) * | 2011-12-31 | 2012-10-17 | 清华大学 | Method for data transmission by using voice-like modulation and demodulation |
| CN102868466A (en) * | 2012-09-20 | 2013-01-09 | 成都林海电子有限责任公司 | Simulation device and method for transmitting 2fsk data through simulated global system for mobile communications (GSM) channel |
| CN102892127A (en) * | 2012-09-20 | 2013-01-23 | 成都林海电子有限责任公司 | Simulating apparatus and method for receiving 2 frequency shift keying (2fsk) data by simulating global system for mobile communications (GSM) channel |
| CN104702550A (en) * | 2015-03-12 | 2015-06-10 | 灵芯微电子科技（苏州）有限公司 | Digital detection and error correction algorithm applied to FSK (Frequency Shift Keying) modulating system |
| CN108282790A (en) * | 2017-01-06 | 2018-07-13 | 鼎点视讯科技有限公司 | Channel plan method and system |
| CN109346092A (en) * | 2018-10-29 | 2019-02-15 | 王秉玉 | The system and method for voice encryption communication is carried out between a kind of communication terminal |
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| US4675863A (en) * | 1985-03-20 | 1987-06-23 | International Mobile Machines Corp. | Subscriber RF telephone system for providing multiple speech and/or data signals simultaneously over either a single or a plurality of RF channels |
| FI98024C (en) * | 1995-05-11 | 1997-03-25 | Nokia Telecommunications Oy | Procedure and apparatus for transferring file-based multimedia and hypermedia service to a mobile receiver |
| US6493338B1 (en) * | 1997-05-19 | 2002-12-10 | Airbiquity Inc. | Multichannel in-band signaling for data communications over digital wireless telecommunications networks |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101631327B (en) * | 2009-08-04 | 2012-08-08 | 华为技术有限公司 | Method for sending and receiving microwave business data, device thereof and transceiver system |
| CN102737637A (en) * | 2011-12-31 | 2012-10-17 | 清华大学 | Method for data transmission by using voice-like modulation and demodulation |
| CN102737637B (en) * | 2011-12-31 | 2013-11-27 | 清华大学 | Method for data transmission by using voice-like modulation and demodulation |
| CN102868466A (en) * | 2012-09-20 | 2013-01-09 | 成都林海电子有限责任公司 | Simulation device and method for transmitting 2fsk data through simulated global system for mobile communications (GSM) channel |
| CN102892127A (en) * | 2012-09-20 | 2013-01-23 | 成都林海电子有限责任公司 | Simulating apparatus and method for receiving 2 frequency shift keying (2fsk) data by simulating global system for mobile communications (GSM) channel |
| CN102892127B (en) * | 2012-09-20 | 2015-07-08 | 成都林海电子有限责任公司 | Simulating apparatus and method for receiving 2 frequency shift keying (2fsk) data by simulating global system for mobile communications (GSM) channel |
| CN102868466B (en) * | 2012-09-20 | 2015-07-15 | 成都林海电子有限责任公司 | Simulation device and method for transmitting 2fsk data through simulated global system for mobile communications (GSM) channel |
| CN104702550A (en) * | 2015-03-12 | 2015-06-10 | 灵芯微电子科技（苏州）有限公司 | Digital detection and error correction algorithm applied to FSK (Frequency Shift Keying) modulating system |
| CN108282790A (en) * | 2017-01-06 | 2018-07-13 | 鼎点视讯科技有限公司 | Channel plan method and system |
| CN109346092A (en) * | 2018-10-29 | 2019-02-15 | 王秉玉 | The system and method for voice encryption communication is carried out between a kind of communication terminal |
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