CN102075471B - Gaussian filter minimum shift frequency keying-based optical wireless fusion system and method - Google Patents
Gaussian filter minimum shift frequency keying-based optical wireless fusion system and method Download PDFInfo
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Abstract
The invention provides a Gaussian filter minimum shift frequency keying-based optical wireless fusion system and a Gaussian filter minimum shift frequency keying-based optical wireless fusion method. In the system, a signal device comprises N signal source modules, wherein each signal source module generates two analog electrical signals; a link device performs optical modulation on received analog electrical signals through an optical link, and transmits N modulated independent optical signals and an unmodulated optical signal; and a receiving device processes the received N modulated independent optical signals and the unmodulated optical signal to acquire information-carrying data so as to realize optical wireless fusion transmission. The method and the system can reduce system cost, improve system performance, and effectively provide multi-user services.
Description
Technical field
The present invention relates to the communication technology, particularly a kind of system and method for light wireless fusion of the high communication quality based on Gaussian Minimum Shift-frequency Keying (GMSK)
Background technology
The global tide of IT application in recent years makes people improve rapidly the capacity of communication system and the requirement of quality, and broadband wireless access is becoming the main development direction of future communications.Although the access in radio take the optical fiber access as representative can provide very large bandwidth, the mobility of terminal is restricted.Wireless mobile communications is because flexibility and the ambulant advantage of its access more are subjected to user's favor, but present low frequency wireless communication system bandwidth is narrower, can't satisfy the broadband business demands such as following mobile multimedia, Streaming Media.Nowadays, a kind of novel communication technology that merges optical fiber communication and wireless mobile telecommunication technology advantage-light wireless fusion (ROF) is suggested.Fully in conjunction with the characteristics of optical fiber and high frequency radio wave transmission, it has following advantage for it:
1: power loss reduces, system cost reduces.In the ROF system, adopt optical fiber to transmit millimeter-wave signal as transmission medium, because optical fiber has low-loss characteristic, signal is in the less situation of delivering power, can in optical fiber, transmit larger distance, greatly reduce the power loss of system, reduce the cost of system.
2: system bandwidth improves.ROF utilizes optical fiber to come signal transmission,, optical fiber has huge loan resource, these three low loss window of 850nm, 1310nm and 1550nm, total can provide the bandwidth resources of 50THz, has improved greatly the bandwidth of system.
3: be not subjected to electromagnetic interference.The ROF technology is carried in millimeter-wave signal on the light wave and in optical fiber to be transmitted, and can not be subject to the interference of external electromagnetic ripple, also can not produce to external world electromagnetic interference simultaneously.
4: the very big application of multioperation, multiservice communication.The ROF technology can satisfy the flexibility of system level operation, can realize the transparence of signal format, low-loss single-mode optical fiber and radio-frequency carrier modulation technique can be combined and be designed to a transparent linear system, make the ROF system can be used for supporting distribution multioperation, multiservice communication professional.
Along with the development of the communication technology, modulation system is divided into two kinds of analog-modulated and Digital Modulations haply by the form of modulation signal.Analog-modulated roughly has phase-modulation (PM), frequency modulation(FM) (FM), amplitude modulation(PAM) (AM) etc.; Digital Modulation roughly has phase deviation modulation (PSK), frequency shift (FS) modulation (FSK), amplitude offset modulation (ASK) etc.A kind of minimum shift keying (GMSK) from the next digital modulation mode-gaussian filtering of minimum shift keying (MSK) development is the modulation system that global system for mobile communications (GSM) adopts, be the study hotspot in current modern digital modulation technique field, obtain a wide range of applications.It has constant envelope, and envelope rises and falls very little; With respect to MSK, its power spectrum side lobe attenuation is faster; It can effectively support many services, multi-user's application.
The ROF technology based on GMSK with so many advantage has broad application prospects at vehicle-mounted mobile communication, hot zones and the aspects such as indoor covering, Radar Signal Transmission, for example in broadband fixed radio access (FWA) system and special-purpose Small Extension Node. Communications (DSRC) system, can improve greatly the bandwidth of communication system, the transmission rate of raising system can effectively solve the frequency spectrum resource problem in short supply of low-frequency range.Yet, in utilizing the ROF system of monomode fiber, because being modulated on the light wave, radiofrequency signal can produce a plurality of light wave compositions that frequency interval equals radio frequency signal frequency, increase along with the frequency of radiofrequency signal, the length of optical fiber dispersion limit fibre link, cause simultaneously the correlation of signal phase to reduce, and then increase the phase noise of radio-frequency carrier, restriction link bandwidth and transmission range.So we will study in the radiofrequency signal situation than low frequency, realize the system and method based on the ROF of GMSK.
Fig. 1 is the structural representation of existing ROF system based on quaternary PSK (QPSK), and is existing in conjunction with Fig. 1, and the structure of existing ROF system based on QPSK is described, specific as follows:
Existing ROF system based on QPSK comprises: signal source module 10 and optical link module 11.
Above-mentioned is the light wireless fusion system of existing minimum shift keying based on gaussian filtering, this system can tentatively realize the signal transmission that optical communication and radio communication merge, but owing to adopted the QPSK modulation format, can not effectively resist the impact of non-linear and Doppler's translation etc. of the channel that signal is subject in transmission course, can not support whole system to many services, multi-user's future development, make through the error rate after the radiofrequency signal reception of ROF transmission transmission higher, affected to a great extent the systematic function of ROF, also limited the ROF system in many services, multi-user's application has affected the development of ROF system to a great extent.
Summary of the invention
In view of this, the object of the present invention is to provide a kind of light wireless fusion system based on Gaussian Minimum Shift-frequency Keying (GMSK), this system can reduce system cost, improves the ROF systematic function, and multi-user services is provided.
Another object of the present invention is to provide a kind of light wireless fusion method based on Gaussian Minimum Shift-frequency Keying (GMSK), the method can reduce system cost, improves the ROF systematic function, and multi-user services is provided.
For achieving the above object, technical scheme of the present invention specifically is achieved in that
A kind of light wireless fusion (ROF) system based on Gaussian Minimum Shift-frequency Keying (GMSK), this system comprises: signalling, chain circuit device and receiving system:
Described signalling comprises N signal source module, for generation of 2N road analog electrical signal to chain circuit device; Each signal source module in the described N signal source module utilizes address logic to produce the two-way digital electric signal, and utilize respectively digital-to-analogue conversion to be translated into the analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal, the output analog electrical signal is to chain circuit device; Described address logic is the corresponding sine in address, the cosine function value table that is generated by system logic; Described digital-to-analogue conversion is that digital signal is converted to analog signal; Described N is the positive integer more than or equal to 1;
Described chain circuit device utilizes independently light signal of wide range light signal generating N+1 road, the light signal on the N road of wherein modulating is modulated by external modulation technology and the analog electrical signal that receives, and the light signal of output N road GMSK modulation and one road unmodulated light signal are to receiving system; Described external modulation technology refers to not to be signal directly to be loaded on the laser modulate, but realizes the light modulation techniques of signal modulation on the modulator externally; The sequence number of the light signal on described N road of modulating is i; The sequence number of described unmodulated light signal is 0; Described i is more than or equal to 1 and less than or equal to the positive integer of N;
Described receiving system is used for will be to the N+1 road light signal that receives, and i road light signal and the 0 road light signal utilize opto-electronic conversion, obtains one the tunnel and is fit to the analog electrical signal that transmitting terminal is launched, and analog electrical signal is received and processes the data that obtain inclusion information; Described opto-electronic conversion namely utilizes photoelectric effect that light signal is converted to corresponding electric signal; Described transmitting terminal is for being fit to the antenna of transmitted signal;
In said apparatus, each signal source module in the described signalling comprises:
Pulse train is carried out shaping by offset of sinusoidal ripple signal, and sinusoidal signal is shaped as the pulse sequence signal that system needs, and exports the address logic module to;
Address logic, be used for the pulse train that receives is converted to corresponding sine, cosine function value, by being solidificated in the random data table in the internal memory, take out corresponding signal discrete value according to the address, pulse sequence signal is converted to sine, cosine waveform digital electric signal, respectively output independently the 2i-1 railway digital signal of telecommunication and the 2i railway digital signal of telecommunication to its digital to analog converter;
Digital-to-analogue conversion, be used for respectively the 2i-1 railway digital signal of telecommunication that receives and the 2i railway digital signal of telecommunication are converted to the analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal, pass through analog operational circuit, digital electric signal is converted to corresponding analog electrical signal, exports 2i-1 road analog electrical signal and 2i road analog electrical signal to chain circuit device;
In said apparatus, described chain circuit device comprises:
Wide spectrum light source for generation of the light signal that is adapted at transmitting on the optical fiber, as the light signal in the link, is exported suitable light signal to comb filter;
Comb filter, the light signal that contains a plurality of frequencies for receiving by pressing passband and the stopband of certain frequency interval aligned identical, only allows the signal of some characteristic frequency pass through, select the light signal of the frequency that needs, the individual independently light signal of the N+1 that output is selected is to channel-splitting filter;
Channel-splitting filter is used for the N+1 that receives that independently light signal is separated from one another comes, and enters respectively different light paths and transmits, and exports i road light signal to splitter i, exports the 0 road light signal to multiplexer;
Splitter i is used for 2i-1 and 2i road light signal that an i road light signal that receives is divided into the same nature of two-way parallel transmission, exports 2i-1 road light signal to the pi/2 phase shift module, exports 2i road light signal to signal modulator 2i;
The pi/2 phase shift module, be used for the phase place of the 2i-1 road light signal that receives is carried out the variation of pi/2, guaranteed that the pi/2 phase between 2i-1 road light signal and the 2i road light signal is poor, guaranteed the orthogonality relation between the two paths of signals, the light signal after the output phase shift is to signal modulator 2i-1;
Signal modulator, be used for the 2N road analog electrical signal that receives is modulated to light signal, 2N road light signal entering signal modulator, and the signal of telecommunication control end of the 2N road analog electrical signal entering signal modulator that is provided by signalling, voltage by the signal modulator offset side constantly changes, realize analog signal to the modulation of light signal, and export modulated 2N road light signal to summation module;
Summation module is used for the 2i-1 road light signal and the 2i road light signal that receive are combined into the light signal that transmits on the optical link, and the light signal of output N road independence GMSK modulation is to multiplexer;
Multiplexer, be used for receiving modulated N road independently the same direction that is bonded on one road route of light signal and unmodulated one road optical multiplexed signal transmit, export signal after compound to image intensifer;
Image intensifer for a light signal that receives is carried out the as far as possible little amplification of distortion, has been avoided like this decaying after the signal long-distance transmission and has been obscured in noise too greatly, causes and can't accurately the signal demodulation out, export optical fiber to;
Optical fiber for the path that long Distance Transmission is provided to light signal, exports receiving system as transmission medium to;
In said apparatus, described receiving system comprises:
Demodulation multiplexer is cut apart the road light signal that contains N+1 centre frequency that receives, and obtains independently light signal of N+1 road, exports the 0 road light signal to band pass filter 0, exports i road light signal to band pass filter i;
Optical band pass filter is used for the light signal that receives is carried out bandpass filtering, and optical band pass filter 0 exports splitter 0 to, and optical band pass filter i exports summation module i to; Described light belt pass filter namely only passes through centre frequency, filtering low-and high-frequency light signal;
Splitter 0 is used for the N road light signal that the 0 road light signal that receives is divided into the same nature of parallel transmission, exports respectively N summation module to;
Summation module i is used for the i road light signal and the 0 road light signal that receive are combined into the light signal that transmits on the optical link, and output optical signal is to photoelectric detector i;
Photoelectric detector i is used for the synthetic light signal of an i road light signal that receives and the 0 road light signal, is converted to associated analog electrical signal by photoelectric effect, exports phase locking unit i to;
Phase locking unit i is used for the phase place of the analog electrical signal that receives is locked, and has guaranteed that like this phase place of signal is constant, reduces the interference of the phase noise that brings in the photoelectric conversion process, exports summation module to;
Summation module is used for the N road analog electrical signal that receives is utilized the add circuit addition together, sends, and exports antenna to;
Antenna is used for the analog electrical signal that receives is launched;
The light wireless fusion method of a kind of minimum shift keying based on gaussian filtering (GMSK), the method comprises:
A, by input with adjust data parameters in N the module, utilize address logic generation digital electric signal, and utilize digital-to-analogue conversion to be translated into the 2N road analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal; Described address logic is the corresponding sine in address, the cosine function value table that is generated by system logic; Described digital-to-analogue conversion is that digital signal is converted to analog signal; Described N is the positive integer more than or equal to 1;
B, utilize independently light signal of wide range light signal generating N+1 road, light signal to N road is wherein modulated by external modulation technology and the analog electrical signal that receives, one road light signal is not modulated, and the compound N road light signal of modulating and unmodulated light signal; Described external modulation technology refers to not to be signal directly to be loaded on the laser modulate, but realizes the light modulation techniques of signal modulation on the modulator externally; The sequence number of the described N road light signal of modulating is i; The sequence number of described unmodulated light signal is 0; Described i is more than or equal to 1 and less than or equal to the positive integer of N;
C, the N+1 road light signal to receiving, i road light signal and the 0 road light signal utilize opto-electronic conversion, obtain the analog electrical signal of one road suitable transmitting terminal, analog electrical signal are received and processes the data that obtain inclusion information; Described opto-electronic conversion namely utilizes photoelectric effect that light signal is converted to corresponding electric signal; Described transmitting terminal is for being fit to the antenna of transmitted signal;
In the said method, steps A is described by the data parameters in input and the adjusting module, utilize address logic to produce digital electric signal, and the method for utilizing digital-to-analogue conversion to be translated into the analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal comprises:
A1, in N AWG (Arbitrary Waveform Generator) of N road serial binary high-speed data bit input, by cos (t) and two tables of sin θ (t) of making in advance in the address logic, read out respectively corresponding numerical value, obtain corresponding cos θ (t) and sin θ (t) waveform;
A2, the digital electric signal that obtains is gone here and there and changed, obtain the parallel data signal of two-way identical data transmission rate;
A3, the digital data signal that two-way is parallel carry out digital-to-analogue conversion, and carry out low-pass filtering, obtain corresponding analog electrical signal; Described low-pass filtering namely utilizes low pass filter that analog signal is carried out filtering, the filtering high-frequency signal;
In the said method, the described independently light signal of wide range light signal generating N+1 road that utilizes of step B, light signal to N road is wherein modulated by external modulation technology and the analog electrical signal that receives, one road light signal is not modulated, and the compound N road light signal of modulating and unmodulated light signal method comprise:
B1, utilize tunable optic filter that the light signal that contains N+1 centre frequency that the wide range laser produces is cut apart, acquisition N+1 road frequency is λ
0, λ
1..., λ
NThe independent light signal;
B2, be λ with frequency
iLight signal be divided into the two ways of optical signals of same nature, one road light signal enters horse pool modulator 2i and modulates with the analog electrical signal that receives; The phase shift of pi/2 is carried out first on another road, enters horse pool modulator 2i-1 again and modulates with the analog electrical signal that receives;
B3, be λ with modulated centre frequency among the step B2
iTwo ways of optical signals be coupled;
B4, be λ with light signal and one road idle frequency after the N road modulation
0Optical multiplexed signal be combined on the same route and transmit;
B5, the light signal on compound N+1 road is carried out the as far as possible little amplification of distortion by Erbium-Doped Fiber Amplifier, and be placed on the optical fiber and transmit;
In the said method, N+1 road light signal to receiving described in the step C, i road light signal and the 0 road light signal utilize opto-electronic conversion, obtain the analog electrical signal of one road suitable emission, and the method that analog electrical signal is received and processes the data that obtain inclusion information comprises:
C1, the light signal that receives is carried out demultiplexing, obtain independently light signal of N+1 road;
C2, be λ with frequency
0The 0 road light signal be divided into the light signal of N road same nature;
C3, i road light signal and the 0 road light signal merged become one road light signal;
C4, by photoelectric detector the synthetic light signal among the step C3 is carried out Photoelectric Detection, the light signal that receives is converted to the signal of telecommunication, the horizontal lock of going forward side by side is processed, and the phase noise that brings in the filtering Photoelectric Detection process obtains one road signal of telecommunication; Described Photoelectric Detection is opto-electronic conversion, is expressed as at mathematics light signal is asked modular arithmetic; Described one road signal of telecommunication comprises direct current signal, modulation signal and corresponding frequency-doubled signal;
C5, the N road signal of telecommunication that step C4 is obtained are synthesized together, and transmit through one section wireless channel module; Described one road signal of telecommunication that step C4 is obtained carries out bandpass filtering, removes the direct current signal and the baseband signal that comprise in the described signal of telecommunication, the mm wave RF signal of the carry information that emission obtains;
C6, to the direct current signal that carries out bandpass filtering through the signal of telecommunication after the wireless channel transmission, remove comprising in the described signal of telecommunication with and frequency-doubled signal, obtain to comprise the N road intermediate frequency analog electrical signal of data message;
C7, N road analog electrical signal is carried out analog-to-digital conversion is digital electric signal, and signal is divided into two-way, and one the tunnel multiplies each other with sine wave signal, and one the tunnel multiplies each other with cosine wave signal; The frequency of described sine wave signal and cosine wave signal is identical with carrier frequency.
C8, two paths of signals is carried out respectively low-pass filtering, leach wherein direct current, radio-frequency component, sampling, judgement that the signal that obtains is pursued symbol.
C9, carry out parallel-serial conversion, obtain N road serial binary high-speed data bit.
By above technical scheme as seen, the invention provides a kind of system and method for the light wireless fusion based on Gaussian Minimum Shift-frequency Keying (GMSK), utilize GMSK that data message is modulated in this system, and use the signal of N road carry information to transmit simultaneously, with respect to existing ROF system based on QPSK, it has improved the capacity of system greatly, so that a plurality of user can be transmitted simultaneously, effectively provides a kind of system and method for multi-user communication.
Description of drawings
Fig. 1 is the structural representation of the ROF system of existing QPSK.
Fig. 2 is the structural representation that the present invention is based on the light wireless fusion system of Gaussian Minimum Shift-frequency Keying.
Fig. 3 is the flow chart that the present invention is based on the light wireless fusion method of Gaussian Minimum Shift-frequency Keying.
Embodiment
For make purpose of the present invention, technical scheme, and advantage clearer, referring to the accompanying drawing embodiment that develops simultaneously, the present invention is described in more detail.
The invention provides one based on the light wireless fusion system and method for Gaussian Minimum Shift-frequency Keying, the N that signalling comprises in this a system signal source module utilizes address logic to produce the 2N railway digital signal of telecommunication, and digital to analog converter is converted to analog electrical signal to it; Chain circuit device utilizes independently light signal of wide range light signal generating N+1 road, and the light signal on the N road of wherein modulating is modulated by external modulation technology and the analog electrical signal that receives, light signal and the one road unmodulated light signal of output N road GMSK modulation; Receiving system carries out the opto-electronic conversion processing to the N+1 road light signal that receives, and acquisition is fit to the analog electrical signal of emission, and the data with analog electrical signal reception and processing acquisition inclusion information have realized that the light of GMSK signal infinitely transmits.
Fig. 2 is the structural representation that the present invention is based on the light wireless fusion system of Gaussian Minimum Shift-frequency Keying, and is existing in conjunction with Fig. 2, and the structure of the light wireless fusion system that the present invention is based on Gaussian Minimum Shift-frequency Keying is described, specific as follows:
For sake of clarity, first the light wireless fusion system that the present invention is based on Gaussian Minimum Shift-frequency Keying is defined, the ROF system of GMSK of the present invention can produce the signal of N road carry information, and this N road signal is carried out light modulation and accepts processing, and wherein N is the positive integer more than or equal to 1.
The light wireless fusion system that the present invention is based on Gaussian Minimum Shift-frequency Keying comprises: signalling 20, chain circuit device 21, receiving system 22.
Receiving system 22 is used for will be to the N+1 road light signal that receives, and i road light signal and the 0 road light signal utilize opto-electronic conversion, obtains one the tunnel and is fit to the analog electrical signal that transmitting terminal is launched, and analog electrical signal is received and processes the data that obtain inclusion information; Wherein, opto-electronic conversion namely utilizes photoelectric effect that light signal is converted to corresponding electric signal; Transmitting terminal is for being fit to the antenna of transmitted signal.
Wherein, signalling 20 comprises N AWG (Arbitrary Waveform Generator) (AWG) 200.
AWG (Arbitrary Waveform Generator) (AWG) 200 output analog electrical signals are to chain circuit device 21, and wherein, the AWG (Arbitrary Waveform Generator) that adopts in the system of the present invention can be controlled output signal by control end, and output two-way analog electrical signal is to chain circuit device 21.
Tunable optic filter 211 1 ends link to each other with wide range laser 210, receive the light signal of wide range laser 210 outputs, a road have the light signal of a plurality of frequencies to be divided into the independently different light signal of centre frequency of N+1 road with what receive; Other end output N+1 road is the different light signal of centre frequency independently, and wherein N road light signal is to splitter 212, and one road light signal is to multiplexer 217; Wherein, can adopt the tunable optic filter based on the photon filter of cascade, its basic principle is existing technology contents.The basic principle of existing brief description tunable optic filter 211, be specially: tunable optic filter is formed by two different tunable optical subfilter part cascades, be respectively infinite impulse response (IIR) filter segment and finite impulse response (FIR) (FIR) filter segment, light carrier at first partly forms narrow broadband response through IIR, then by FIR part to the IIR part formed response carry out centre frequency and select, input contains the light signal of N+1 centre frequency through after the effect of filter, and output N+1 road is light signal independently.
Each splitter 212 in N splitter is used for a road light signal that receives from tunable optic filter 211 is divided into the light signal of two-way same nature transmission, exports respectively horse pool modulator 213 and phase-shifter 214 to.
The phase place of the road light signal that phase-shifter 214 will receive is carried out the change of pi/2, and the light signal after the output change phase place is to horse pool modulator 215; Wherein, phase-shifter can adopt the medium phase-shifter, namely inserts the phase place that dieelctric sheet changes light wave and realize in waveguide.
The light signal that adder 216 is used for receiving after the modulation of horse pool modulator 213 and modulator 215 outputs of horse pool synthesizes, and exports one road signal to multiplexer 217.
Receiving system 22 comprises demodulation multiplexer 220, a N optical band pass filter 221, optical band pass filter 222, splitter 223, a N adder 224, a N photoelectric detector 225, a N phase locking unit 226, adder 227, wireless channel 228, a N band pass filter 229 and N off-line digital signal processing 2210.
Optical band pass filter 221 1 ends connect demodulation multiplexer 220, receive the light signal of the modulation of demodulation multiplexer 220 outputs, be used for the light signal that receives is carried out bandpass filtering, remove the Noise and Interference that is mingled with in the independently light signal that receives, export adder 224 to.
Optical band pass filter 222 1 ends connect demodulation multiplexer 220, receive the unmodulated light signal that demodulation multiplexer 220 is breathed out, and export splitter 223 to; Wherein, with optical band pass filter 221 be same during, but output is different.
Splitter 223 is used for the light signal of optical band pass filter 222 outputs that receive is divided into the light signal of N road same nature transmission to adder 224; Wherein, the splitter with chain circuit device is same device.
One termination of phase locking unit 226 is received the signal of telecommunication of photoelectric detector 225 outputs, and the other end exports adder 227 to; Utilize phase-locked loop circuit, the phase place of the signal of telecommunication that receives is locked, to reduce the impact of the phase noise that signal is subject in the Photoelectric Detection process, improve sensitivity, phase locking unit is made of phase-locked loop, and its basic principle is the prior art content.The operation principle of existing brief description phase locking unit 226, specific as follows: phase-locked loop mainly is comprised of phase reference extraction circuit, voltage controlled oscillator, phase comparator, control circuit, what voltage controlled oscillator was exported is the constant-amplitude signal very approaching with needing frequency, send the output signal of voltage controlled oscillator with by the reference signal that phase reference extraction circuit extracts into simultaneously phase comparator from signal, with the error that relatively forms the frequency of voltage controlled oscillator is changed continuously to the direction that reduces Error Absolute Value, realize phase-lockedly, its structure does not repeat them here.
The off-line digital signal processes 2210, is used for the signal that comprises data message that receives is carried out Digital Signal Processing, obtains data message; Wherein, off-line digital signal processing 2210 can adopt Digital Signal Processing (DSP) chip to process to the received signal.
Fig. 3 is the flow chart that the present invention is based on the light wireless fusion method of Gaussian Minimum Shift-frequency Keying.Now in conjunction with Fig. 3, to the light wireless fusion method process specification of invention based on Gaussian Minimum Shift-frequency Keying, specific as follows:
Step 301: by the data parameters in input and N module of adjustment, utilize address logic to produce digital electric signal, and utilize digital-to-analogue conversion to be translated into the 2N road analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal:
In this step, the method that produces 2N road analog electrical signal comprises:
3011: in N AWG (Arbitrary Waveform Generator) of N road serial binary high-speed data bit input, by cos θ (t) and two tables of sin θ (t) of making in advance in the address logic, read out respectively corresponding numerical value, obtain corresponding cos θ (t) and sin θ (t) waveform;
3012: the digital electric signal that obtains is gone here and there and changed, obtain the parallel data signal of two-way identical data transmission rate;
3013: the digital data signal that two-way is parallel carries out digital-to-analogue conversion, and carries out low-pass filtering, obtains corresponding analog electrical signal; Described low-pass filtering namely utilizes low pass filter that analog signal is carried out filtering, the filtering high-frequency signal;
Step 302: utilize independently light signal of wide range light signal generating N+1 road, light signal to N road is wherein modulated by external modulation technology and the analog electrical signal that receives, one road light signal is not modulated, and the compound N road light signal of modulating and unmodulated light signal:
In this step, the method for produce light signal, light signal being modulated comprises:
3021: utilize tunable optic filter that the light signal that contains N+1 centre frequency that the wide range laser produces is cut apart, obtaining N+1 road frequency is λ
0, λ
1..., λ
NThe independent light signal;
3022: be λ with frequency
iLight signal be divided into the two ways of optical signals of same nature, one road light signal enters horse pool modulator 2i and modulates with the analog electrical signal that receives; The phase shift of pi/2 is carried out first on another road, enters horse pool modulator 2i-1 again and modulates with the analog electrical signal that receives;
3023: be λ with modulated centre frequency among the step B2
iTwo ways of optical signals be coupled;
3024: be λ with light signal and one road idle frequency after the N road modulation
0Optical multiplexed signal be combined on the same route and transmit;
3025: the light signal on compound N+1 road is carried out the as far as possible little amplification of distortion by Erbium-Doped Fiber Amplifier, and be placed on the optical fiber and transmit;
Step 303: to the N+1 road light signal that receives, i road light signal and the 0 road light signal utilize opto-electronic conversion, obtain the analog electrical signal of one road suitable emission, analog electrical signal are received and processes the data that obtain inclusion information;
In this step, the method that obtains analog electrical signal and carry out reception ﹠ disposal comprises:
3031: the light signal that receives is carried out demultiplexing, obtain independently light signal of N+1 road;
3032: be λ with frequency
0The 0 road light signal be divided into the light signal of N road same nature;
3033: i road light signal and the merging of the 0 road light signal are become one road light signal;
3034: by photoelectric detector the synthetic light signal among the step C3 is carried out Photoelectric Detection, the light signal that receives is converted to the signal of telecommunication, the horizontal lock of going forward side by side is processed, and the phase noise that brings in the filtering Photoelectric Detection process obtains one road signal of telecommunication; Described Photoelectric Detection is opto-electronic conversion, is expressed as at mathematics light signal is asked modular arithmetic; Described one road signal of telecommunication comprises direct current signal, modulation signal and corresponding frequency-doubled signal;
3035: the N road signal of telecommunication that step C4 is obtained is synthesized together, and transmits through one section wireless channel module; Described one road signal of telecommunication that step C4 is obtained carries out bandpass filtering, removes the direct current signal and the baseband signal that comprise in the described signal of telecommunication, the mm wave RF signal of the carry information that emission obtains;
3036: to carrying out bandpass filtering through the signal of telecommunication after the wireless channel transmission, remove the direct current signal that comprises in the described signal of telecommunication and reaching frequency-doubled signal, obtain to comprise the N road intermediate frequency analog electrical signal of data message;
3037 N road analog electrical signal is carried out analog-to-digital conversion is digital electric signal, and signal is divided into two-way, and one the tunnel multiplies each other with sine wave signal, and one the tunnel multiplies each other with cosine wave signal; The frequency of described sine wave signal and cosine wave signal is identical with carrier frequency.
3038 pairs of two paths of signals carry out respectively low-pass filtering, leach wherein direct current, radio-frequency component, sampling, judgement that the signal that obtains is pursued symbol.
3039: carry out parallel-serial conversion, obtain N road serial binary high-speed data bit.
In the above-mentioned example of the present invention, the data-signal that has comprised the transmission inclusion information on N road is compared with existing ROF system, the transmission by multichannel in same system, can effectively increase the capacity of system, the capability improving that provides the user to serve, the signal of N road transmission is mutually orthogonal, can not produce interference each other, the sensitivity of receiving terminal also can improve, can reduce greatly system cost, improve the ROF systematic function, multi-user services effectively is provided.
The above only is preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of making, is equal to replacement, improvement etc., all should be included within the scope of protection of the invention.
Claims (8)
1. light wireless fusion (ROF) system based on Gaussian Minimum Shift-frequency Keying (GMSK), being used for modulation format is the generation of GMSK signal, use the ROF technology in the optical link processing and transmit this GMSK signal, and the process with its emission reception, it is characterized in that this system comprises: signalling, chain circuit device and receiving system:
Described signalling comprises N signal source module, for generation of 2N road analog electrical signal to chain circuit device; Each signal source module in the described N signal source module utilizes address logic to produce the two-way digital electric signal, and utilize respectively digital-to-analogue conversion to be translated into the analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal, the output analog electrical signal is to chain circuit device; Described address logic is the corresponding sine in address, the cosine function value table that is generated by system logic; Described digital-to-analogue conversion is that digital signal is converted to analog signal; Described N is the positive integer more than or equal to 1;
Described chain circuit device utilizes independently light signal of wide range light signal generating N+1 road, the light signal on the N road of wherein modulating is modulated by external modulation technology and the analog electrical signal that receives, and the light signal of output N road GMSK modulation and one road unmodulated light signal are to receiving system; Described external modulation technology refers to not to be signal directly to be loaded on the laser modulate, but realizes the light modulation techniques of signal modulation on the modulator externally; The sequence number of the light signal on described N road of modulating is i; The sequence number of described unmodulated light signal is 0; Described i is more than or equal to 1 and less than or equal to the positive integer of N;
Described receiving system is used for will be to the N+1 road light signal that receives, and i road light signal and the 0 road light signal utilize opto-electronic conversion, obtains one the tunnel and is fit to the analog electrical signal that transmitting terminal is launched, and analog electrical signal is received and processes the data that obtain inclusion information; Described opto-electronic conversion namely utilizes photoelectric effect that light signal is converted to corresponding electric signal; Described transmitting terminal is for being fit to the antenna of transmitted signal.
2. the light wireless fusion system of the minimum shift keying based on gaussian filtering according to claim 1 is characterized in that each signal source module in the described N signal source module comprises:
Pulse train is carried out shaping by offset of sinusoidal ripple signal, and sinusoidal signal is shaped as the pulse sequence signal that system needs, and exports the address logic module to;
Address logic, be used for the pulse train that receives is converted to corresponding sine, cosine function value, by being solidificated in the random data table in the internal memory, take out corresponding signal discrete value according to the address, pulse sequence signal is converted to sine, cosine waveform digital electric signal, respectively output independently the 2i-1 railway digital signal of telecommunication and the 2i railway digital signal of telecommunication to its digital to analog converter;
Digital-to-analogue conversion, be used for respectively the 2i-1 railway digital signal of telecommunication that receives and the 2i railway digital signal of telecommunication are converted to the analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal, pass through analog operational circuit, digital electric signal is converted to corresponding analog electrical signal, exports 2i-1 road analog electrical signal and 2i road analog electrical signal to chain circuit device.
3. the light wireless fusion system of the minimum shift keying based on gaussian filtering according to claim 1 is characterized in that described chain circuit device comprises:
Wide spectrum light source for generation of the light signal that is adapted at transmitting on the optical fiber, as the light signal in the link, is exported suitable light signal to comb filter;
Comb filter, for the light signal that contains a plurality of frequencies that will receive, passband and stopband by the frequency interval aligned identical that sets by comb filter, only allow the signal of the frequency that comb filter sets pass through, select the light signal of the frequency that needs, the individual independently light signal of the N+1 that output is selected is to channel-splitting filter;
Channel-splitting filter is used for the N+1 that receives that independently light signal is separated from one another comes, and enters respectively different light paths and transmits, and exports i road light signal to splitter i, exports the 0 road light signal to multiplexer;
Splitter i is used for 2i-1 and 2i road light signal that an i road light signal that receives is divided into the same nature of two-way parallel transmission, exports 2i-1 road light signal to the pi/2 phase shift module, exports 2i road light signal to signal modulator 2i;
The pi/2 phase shift module, be used for the phase place of the 2i-1 road light signal that receives is carried out the variation of pi/2, guaranteed that the pi/2 phase between 2i-1 road light signal and the 2i road light signal is poor, guaranteed the orthogonality relation between the two paths of signals, the light signal after the output phase shift is to signal modulator 2i-1;
Signal modulator, be used for the 2N road analog electrical signal that receives is modulated to light signal, 2N road light signal entering signal modulator, and the signal of telecommunication control end of the 2N road analog electrical signal entering signal modulator that is provided by signalling, voltage by the signal modulator offset side constantly changes, realize analog signal to the modulation of light signal, and export modulated 2N road light signal to summation module;
Summation module is used for the 2i-1 road light signal and the 2i road light signal that receive are combined into the light signal that transmits on the optical link, and the light signal of output N road independence GMSK modulation is to multiplexer;
Multiplexer, be used for receiving modulated N road independently the same direction that is bonded on one road route of light signal and unmodulated one road optical multiplexed signal transmit, export signal after compound to image intensifer;
Image intensifer for a light signal that receives is carried out the as far as possible little amplification of distortion, has been avoided like this decaying after the signal long-distance transmission and has been obscured in noise too greatly, causes and can't accurately the signal demodulation out, export optical fiber to;
Optical fiber for the path that long Distance Transmission is provided to light signal, exports receiving system as transmission medium to.
4. the light wireless fusion system of the minimum shift keying based on gaussian filtering according to claim 1 is characterized in that described receiving system comprises:
Demodulation multiplexer is cut apart the road light signal that contains N+1 centre frequency that receives, and obtains independently light signal of N+1 road, exports the 0 road light signal to band pass filter 0, exports i road light signal to band pass filter i;
Optical band pass filter is used for the light signal that receives is carried out bandpass filtering, and optical band pass filter 0 exports splitter 0 to, and optical band pass filter i exports summation module i to; Described bandpass filtering namely only passes through centre frequency, filtering low-and high-frequency light signal;
Splitter 0 is used for the N road light signal that the 0 road light signal that receives is divided into the same nature of parallel transmission, exports respectively N summation module to;
Summation module i is used for the i road light signal and the 0 road light signal that receive are combined into the light signal that transmits on the optical link, and output optical signal is to photoelectric detector i;
Photoelectric detector i is used for the synthetic light signal of an i road light signal that receives and the 0 road light signal, is converted to associated analog electrical signal by photoelectric effect, exports phase locking unit i to;
Phase locking unit i is used for the phase place of the analog electrical signal that receives is locked, and has guaranteed that like this phase place of signal is constant, reduces the interference of the phase noise that brings in the photoelectric conversion process, exports summation module to;
Summation module is used for the N road analog electrical signal that receives is utilized the add circuit addition together, sends, and exports antenna to;
Antenna is used for the analog electrical signal that receives is launched.
5. light wireless fusion method based on the minimum shift keying of gaussian filtering is characterized in that the method comprises:
A, by input with adjust data parameters in N the module, utilize address logic generation digital electric signal, and utilize digital-to-analogue conversion to be translated into the 2N road analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal; Described address logic is the corresponding sine in address, the cosine function value table that is generated by system logic; Described digital-to-analogue conversion is that digital signal is converted to analog signal; Described N is the positive integer more than or equal to 1;
B, utilize independently light signal of wide range light signal generating N+1 road, light signal to N road is wherein modulated by external modulation technology and the analog electrical signal that receives, one road light signal is not modulated, and the compound N road light signal of modulating and unmodulated light signal; Described external modulation technology refers to not to be signal directly to be loaded on the laser modulate, but realizes the light modulation techniques of signal modulation on the modulator externally; The sequence number of the described N road light signal of modulating is i; The sequence number of described unmodulated light signal is 0; Described i is more than or equal to 1 and less than or equal to the positive integer of N;
C, the N+1 road light signal to receiving, i road light signal and the 0 road light signal utilize opto-electronic conversion, obtain one the tunnel and are fit to the analog electrical signal that transmitting terminal is launched, and analog electrical signal are received and processes the data that obtain inclusion information; Described opto-electronic conversion namely utilizes photoelectric effect that light signal is converted to corresponding electric signal; Described transmitting terminal is for being fit to the antenna of transmitted signal.
6. method according to claim 5, it is characterized in that, steps A is described by the data parameters in input and the adjusting module, utilize address logic to produce digital electric signal, and the method for utilizing digital-to-analogue conversion to be translated into the analog electrical signal of the higher waveform of spectrum efficiency and suitable modulated light signal comprises:
A1, in N AWG (Arbitrary Waveform Generator) of N road serial binary high-speed data bit input, by cos θ (t) and two tables of sin θ (t) of making in advance in the address logic, read out respectively corresponding numerical value, obtain corresponding cos θ (t) and sin θ (t) waveform;
A2, the digital electric signal that obtains is gone here and there and changed, obtain the parallel data signal of two-way identical data transmission rate;
A3, the digital data signal that two-way is parallel carry out digital-to-analogue conversion, and carry out low-pass filtering, obtain corresponding analog electrical signal; Described low-pass filtering namely utilizes low pass filter that analog signal is carried out filtering, the filtering high-frequency signal.
7. method according to claim 5, it is characterized in that, the described independently light signal of wide range light signal generating N+1 road that utilizes of step B, light signal to N road is wherein modulated by external modulation technology and the analog electrical signal that receives, one road light signal is not modulated, and the compound N road light signal of modulating and unmodulated light signal method comprise:
B1, utilize tunable optic filter that the light signal that contains N+1 centre frequency that the wide range laser produces is cut apart, acquisition N+1 road frequency is λ
0, λ
1..., λ
NThe independent light signal;
B2, be λ with frequency
iLight signal be divided into the two ways of optical signals of same nature, one road light signal enters horse pool modulator 2i and modulates with the analog electrical signal that receives; The phase shift of pi/2 is carried out first on another road, enters horse pool modulator 2i-1 again and modulates with the analog electrical signal that receives;
B3, be λ with modulated centre frequency among the step B2
iTwo ways of optical signals be coupled;
B4, be λ with light signal and one road idle frequency after the N road modulation
0Optical multiplexed signal be combined on the same route and transmit;
B5, the light signal on compound N+1 road is carried out the as far as possible little amplification of distortion by Erbium-Doped Fiber Amplifier, and be placed on the optical fiber and transmit.
8. method according to claim 5, it is characterized in that, N+1 road light signal to receiving described in the step C, i road light signal and the 0 road light signal utilize opto-electronic conversion, obtain one the tunnel and be fit to the analog electrical signal that transmitting terminal is launched, the method that analog electrical signal is received and processes the data that obtain inclusion information comprises:
C1, the light signal that receives is carried out demultiplexing, obtain independently light signal of N+1 road;
C2, be λ with frequency
0The 0 road light signal be divided into the light signal of N road same nature;
C3, i road light signal and the 0 road light signal merged become one road light signal;
C4, by photoelectric detector the synthetic light signal among the step C3 is carried out Photoelectric Detection, the light signal that receives is converted to the signal of telecommunication, the horizontal lock of going forward side by side is processed, and the phase noise that brings in the filtering Photoelectric Detection process obtains one road signal of telecommunication; Described Photoelectric Detection is opto-electronic conversion, is expressed as at mathematics light signal is asked modular arithmetic; Described one road signal of telecommunication comprises direct current signal, modulation signal and corresponding frequency-doubled signal;
C5, the N road signal of telecommunication that step C4 is obtained are synthesized together, and transmit through one section wireless channel module; Described one road signal of telecommunication that step C4 is obtained carries out bandpass filtering, removes the direct current signal and the baseband signal that comprise in the described signal of telecommunication, the mm wave RF signal of the carry information that emission obtains;
C6, to the direct current signal that carries out bandpass filtering through the signal of telecommunication after the wireless channel transmission, remove comprising in the described signal of telecommunication with and frequency-doubled signal, obtain to comprise the N road intermediate frequency analog electrical signal of data message;
C7, N road analog electrical signal is carried out analog-to-digital conversion is digital electric signal, and signal is divided into two-way, and one the tunnel multiplies each other with sine wave signal, and one the tunnel multiplies each other with cosine wave signal; The frequency of described sine wave signal and cosine wave signal is identical with carrier frequency;
C8, two paths of signals is carried out respectively low-pass filtering, leach wherein direct current, radio-frequency component, sampling, judgement that the signal that obtains is pursued symbol;
C9, carry out parallel-serial conversion, obtain N road serial binary high-speed data bit.
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