CN206181027U - Optimum position relay of serial is forwardded in relevant OFDM decoding of free space optical communications - Google Patents
Optimum position relay of serial is forwardded in relevant OFDM decoding of free space optical communications Download PDFInfo
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- CN206181027U CN206181027U CN201621267116.2U CN201621267116U CN206181027U CN 206181027 U CN206181027 U CN 206181027U CN 201621267116 U CN201621267116 U CN 201621267116U CN 206181027 U CN206181027 U CN 206181027U
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Abstract
The utility model discloses an optimum position relay of serial is forwardded in relevant OFDM decoding of free space optical communications, its characterized in that, it includes consecutive transmitting terminal, a k DF relay node and receiving terminal, wherein k is the positive integer, a k DF relay node lay the transmitting terminal to the straight line of receiving terminal, fall into the k+1 equal portions with the transmitting terminal to the straight line of receiving terminal. The utility model discloses a relevant OFDM technique, the signal -to -Noise height has better stability, and the frequency band high -usage, the bandwidth expansibility is better and the interference killing feature is strong, continuous DF relay node is equidistant to place the distance of extension communication that can be fine, has broken through free space optical communications's a limit in distance to comparing to enlarge and forwardding (AF) relaying, the DF relaying can effectively reduce the outage probability, improves communication reliability, and this device simple structure, easily practical.
Description
Technical field
The utility model is related to a kind of relevant OFDM (Orthogonal Frequency Division
Multiplexing, OFDM) optimal location relay, more particularly to a kind of FSO is relevant
OFDM decoding forwarding serial optimal location relay systems.
Background technology
FSO (FSO) is a kind of sighting distance (LOS) transmission technology, and it passes through with visible ray as information carrier
The information such as propagation in atmosphere data, image, language.Using the mode similar to fiber optic communication, Free Space Optics are using luminous two
Pole pipe (LED) or laser carry out data transmission.Conventional optical communication guides light beam to be communicated by fiber optic cables, and in free sky
Between light beam conducted by space in optics communicated.FSO has many advantages：1. different from wireless and microwave system, FSO is not
Need to apply for frequency spectrum licences, and do not interfere between other systems；2. point-to-point laser signal is difficult to be prevented from, and this makes
Obtaining it becomes preferable secure communication mode；3.FSO only obtains comparativity pole by cost of the partial development cost of fiber optic communication
High message transmission rate, and extremely narrow laser beam causes the optical link number provided on location in free space
Have no to limit.However, although FSO has the advantages that numerous, its extensive application nevertheless suffers from restriction.Air in signal transmission
The problems such as decay, link alignment, has become the bottleneck for limiting FSO systems communication distance and communication performance.
By introducing relaying, long link is broken down into a plurality of short chain road, and end to end communication reliability can be lifted effectively,
Breach the restriction of communication distance.Majid Safari of University of Waterloo (CA) Waterloo, Ontario, N2L3GI Canada in 2013 et al. propose relaying optimal location, in
After reduction of the position to outage probability have positive effect, used herein is BPPM technologies, and compares BPPM technologies, using just
Frequency division multiplexing (OFDM) technology is handed over to produce higher data rate, it is also possible to effectively to suppress intersymbol interference (ISI), because
Strong, the higher band efficiency of its opposing frequency selective fading and narrow-band noise ability, can well suppress atmospheric channel
The random fading effect for causing.2014 Nian Tang Xuan etc. propose multi-hop DPSK FSO systems, use amplification forwarding (AF) relaying
Scheme, by introducing AF relayings, the communication distance of system substantially increases, and communication reliability improves；AF relayings are without docking
The collection of letters number performs any decoding, and need to only be multiplied by certain suitable energy ratio item, then simply forwards it to the next one
Relaying, but also noise can be amplified while being amplified to signal, have the shortcomings that noise is transmitted.
Utility model content
The purpose of this utility model is for existing deficiency, there is provided a kind of relevant OFDM decodings of FSO
Forwarding serial optimal location relay.
The purpose of this utility model is achieved through the following technical solutions：A kind of FSO is concerned with OFDM
Decoding forwarding serial optimal location relay, it includes transmitting terminal, k DF via node and the receiving terminal being sequentially connected, its
Middle k is positive integer；K DF via node is placed in transmitting terminal to the straight line of receiving terminal, by the straight line of transmitting terminal to receiving terminal
It is divided into k+1 equal portions.
Further, the transmitting terminal includes the first low pass filter, the first frequency mixer, the filter of the first band logical being sequentially connected
Ripple device, the first Mach-Zehnder modulators, the first optical band pass filter and the first transmitting antenna；First Mach-Zehnder
Modulator is also associated with first laser device.
Further, the DF via nodes include be sequentially connected the first reception antenna, the first magnitude amplifier, first
Optical mixer unit, the second optical band pass filter, the first photodetector, the second bandpass filter, the second frequency mixer, the second low pass filtered
Ripple device, OFDM transmitter modules, the 3rd low pass filter, three-mixer, the 3rd bandpass filter, the second Mach-Zehnder are adjusted
Device processed, the 3rd optical band pass filter, the second transmitting antenna；Second laser is also associated with first optical mixer unit, it is described
The 3rd laser instrument is also associated with second Mach-Zehnder modulators.
Further, the receiving terminal includes that the second reception antenna being sequentially connected, the second magnitude amplifier, the second light are mixed
Frequency device, the 4th optical band pass filter, the second photodetector, the 4th bandpass filter, the 4th frequency mixer and the 4th LPF
Device；The 4th laser instrument is also associated with second optical mixer unit.
Further, the length per equal portions is not more than a km.
The beneficial effects of the utility model are：Using relevant OFDM technology, Signal-to-Noise is high to be had more the utility model
Good stability, and band efficiency is high, bandwidth expansion preferably and strong antijamming capability；Between continuous DF via nodes etc.
Can be good at extending the distance for communicating away from placing, the distance for breaching FSO is limited, and compare amplification and turn
(AF) relaying is sent out, DF relayings can effectively reduce outage probability, improve communication reliability；And this apparatus structure is simple, it is real to be easy to
With.
Description of the drawings
Fig. 1 is system architecture schematic block diagram of the present utility model；
Fig. 2 is transmitting terminal structural schematic block diagram of the present utility model；
Fig. 3 is DF via node structural schematic block diagrams of the present utility model；
Fig. 4 is receiving terminal structural schematic block diagram of the present utility model；
In figure, the first low pass filter 1, the first frequency mixer 2, the first bandpass filter 3, first laser device 4, the first horse
Conspicuous-Zeng Deer modulators 5, the first optical band pass filter 6, the first transmitting antenna 7, the first reception antenna 8, the first magnitude amplifier
9th, the first optical mixer unit 10, second laser 11, the second optical band pass filter 12, the first photodetector 13, the filter of the second band logical
Ripple device 14, the second frequency mixer 15, the second low pass filter 16, OFDM transmitter modules 17, the 3rd low pass filter the 18, the 3rd are mixed
Device 19, the 3rd bandpass filter 20, the 3rd laser instrument 21, the second Mach-Zehnder modulators 22, the 3rd optical band pass filter
23rd, the second transmitting antenna 24, the second reception antenna 25, the second magnitude amplifier 26, the second optical mixer unit 27, the 4th laser instrument
28th, the 4th optical band pass filter 29, the second photodetector 30, the 4th bandpass filter 31, the 4th frequency mixer 32, the 4th low pass
Wave filter 33.
Specific embodiment
The utility model is described further below in conjunction with the accompanying drawings.
As shown in figure 1, the utility model provides a kind of FSO relevant OFDM decodings forwarding serial optimum position
Relay is put, it includes transmitting terminal, k DF via node and the receiving terminal being sequentially connected, wherein k is positive integer；Wherein, k
Individual DF via nodes are placed in transmitting terminal to the straight line of receiving terminal, the straight line of transmitting terminal to receiving terminal are divided into into k+1 equal portions, often
The length of equal portions is not more than a km；It is to each other free space atmospheric channel；In figure S be transmitting terminal, d be DF relay wells away from i.e.
Per equal portions length, R be DF via nodes, R1For first DF via node, R2For second DF via node, RkFor k-th
DF via nodes, D is receiving terminal.
As shown in Fig. 2 the transmitting terminal include the first low pass filter 1, the first frequency mixer 2, the first bandpass filter 3,
First laser device 4, the first Mach-Zehnder modulators 5, the first optical band pass filter 6 and the first transmitting antenna 7；Wherein, it is described
First low pass filter 1, the first frequency mixer 2, the first bandpass filter 3 and the first Mach-Zehnder modulators 5 are electrically connected successively
Connect, the first laser device 4 is connected by optical fiber and the first Mach-Zehnder modulators 5, and first Mach-Zehnder is adjusted
Device processed 5, the first optical band pass filter 6, transmitting antenna 7 are sequentially connected by optical fiber.
By external OFDM modulators modulates into ofdm signal, ofdm signal passes through the first LPF to original data signal
Device 1 filters high-frequency noise, again ofdm signal is carried out into frequency spectrum shift in the first frequency mixer 2, by external high-frequency signal LO1Make
Ofdm signal upconverts to a suitable intermediate frequency fLO1On.Signal Jing after frequency conversion filters high frequency by the first bandpass filter 3
With the noise of low frequency component.Because ofdm signal is ambipolar, it is necessary to add a larger direct current biasing to OFDM symbol,
So can ofdm signal negative loop be converted on the occasion of, it is ensured that modulated signal is a unipolar signal.Finally by
One Mach-Zehnder modulators 5 carry out light intensity modulation to first laser device 4, modulate on light carrier, actually modulate first
Mach-Zehnder modulators 5 be ofdm signal real part.Flashlight is transmitted into freedom by the first transmitting antenna 6 after modulation
In room atmosphere channel.
As shown in figure 3, the DF via nodes include the first reception antenna 8, the first magnitude amplifier 9, the first photomixing
Device 10, second laser 11, the second optical band pass filter 12, the first photodetector 13, the second bandpass filter 14, second are mixed
Frequency device 15, the second low pass filter 16, OFDM transmitter modules 17, the 3rd low pass filter 18, three-mixer 19, the 3rd band logical
Wave filter 20, the 3rd laser instrument 21, the second Mach-Zehnder modulators 22, the 3rd optical band pass filter 23, the second transmitting antenna
24；Wherein, first reception antenna 8, the first magnitude amplifier 9, the first optical mixer unit 10, the second optical band pass filter 12,
First photodetector 13 is sequentially connected by optical fiber, and the second laser 11 is by optical fiber and the phase of the first optical mixer unit 10
Even, the photodetector 13 is electrically connected with the second bandpass filter 14, second bandpass filter 14, the second frequency mixer
15th, the second low pass filter 16, OFDM transmitter modules 17, the 3rd low pass filter 18, three-mixer 19, the 3rd bandpass filtering
Device 20, the second Mach-Zehnder modulators 22 are sequentially connected electrically, and the 3rd laser instrument 21 is by optical fiber and second Mach-once
Dare modulator 22 is connected, and second Mach-Zehnder modulators 22, the 3rd optical band pass filter 23, transmitting antenna 24 lead to
Cross optical fiber to be sequentially connected；
First reception antenna 8 is received after the ofdm signal of transmitting terminal transmission, and ofdm signal passes through the first magnitude amplifier 9
Amplify, the local oscillator light LO produced by second laser 111Heterodyne is carried out with the ofdm signal after amplification in the first optical mixer unit 10
Mixing, DC terms and high frequency item are filtered after mixing through the second optical band pass filter 12.Then optical signal enters the first smooth electrical resistivity survey
Survey the probe response electric current of device 13；The electric signal obtained after detection needs to make bandwidth control in intermediate frequency using the second bandpass filter 14
In area detection signal, you can detect intermediate frequency electric signal；The second frequency mixer 15 is needed in the demodulation judging process of electrical domain
Complete, the signal entered per the second frequency mixer 15 all the way is all mutually orthogonal sinusoidal signal and cosine signal sum, to real part
Mixing operations are carried out respectively with imaginary part, i.e., with additional high-frequency signal LO2It is multiplied, the signal after mixing passes through the second LPF
Device 16 can just extract useful real part and imaginary part ofdm signal, and ofdm signal demodulates original number by OFDM transmitter modules 17
It is believed that number and new ofdm signal is re-modulated into it, the ofdm signal of re-modulation is filtered by the 3rd low pass filter 18
High-frequency noise, by ofdm signal carries out frequency spectrum shift, by external high-frequency signal LO again in three-mixer 193Make ofdm signal
Upconvert to a suitable intermediate frequency fLO3On.Signal Jing after frequency conversion filters high and low frequency by the 3rd bandpass filter 20
The noise of component.Because ofdm signal is ambipolar, it is necessary to add a larger direct current biasing to OFDM symbol, so may be used
With ofdm signal negative loop be converted on the occasion of, it is ensured that modulated signal is a unipolar signal.Finally by second Mach-
22 pairs of the 3rd laser instruments 21 of Zeng Deer modulators carry out light intensity modulation, modulate on light carrier, actually modulate second Mach-
Zeng Deer modulators 22 be ofdm signal real part.Flashlight filters DC terms by the 3rd optical band pass filter 23 after modulation
Next relaying is transmitted to high frequency item and then by the second transmitting antenna 24.So circulate until signal is sent to receiving terminal.
As shown in figure 4, the receiving terminal includes the second reception antenna 25, the second magnitude amplifier 26, the second optical mixer unit
27th, the 4th laser instrument 28, the 4th optical band pass filter 29, the second photodetector 30, the 4th bandpass filter the 31, the 4th are mixed
The low pass filter 33 of device 32 and the 4th；Wherein, second reception antenna 25 connects the second magnitude amplifier 26, institute by optical fiber
State the second magnitude amplifier 27, the 4th optical band pass filter 29, the second photodetector 30 to be sequentially connected by optical fiber, described
Four laser instruments 28 are connected by optical fiber with the second magnitude amplifier 27, second photodetector 30, the 4th bandpass filter
31st, the 4th frequency mixer 32 and the 4th low pass filter 33 are sequentially connected electrically.
Second reception antenna connects 25 and receives after the ofdm signal that last relaying sends, and ofdm signal passes through the second amplitude
Amplifier 26 amplifies, the local oscillator light LO produced by the 4th laser instrument 281With the ofdm signal after amplification in the second optical mixer unit 27
Heterodyne mixing is carried out, DC terms and high frequency item are filtered through the 4th optical band pass filter 29 after mixing.Then optical signal enters
The probe response electric current of two photodetector 30；The electric signal obtained after detection needs to make bandwidth control using the 4th bandpass filter 31
System is in intermediate-freuqncy signal detection range, you can detect intermediate frequency electric signal；The 4th is needed to mix in the demodulation judging process of electrical domain
Frequency device 32 completing, enter signal per the 4th frequency mixer 32 all the way all for mutually orthogonal sinusoidal signal and cosine signal it
With carry out mixing operations respectively to real part and imaginary part, i.e., with additional high-frequency signal LO2It is multiplied, the signal after mixing is by the
Four low pass filters 33 can just extract useful real part and imaginary part ofdm signal, and be demodulated by external ofdm demodulator
Original data signal.
The utility model by more than design, can be good at reduce communication outage probability, effectively increase communication away from
From, and this apparatus structure is simple, it is practical to be easy to.
Claims (5)
1. the relevant OFDM decodings of a kind of FSO forward serial optimal location relay, it is characterised in that it is wrapped
Transmitting terminal, k DF via node and the receiving terminal being sequentially connected is included, wherein k is positive integer；K DF via node is placed in be sent out
End is penetrated on the straight line of receiving terminal, the straight line of transmitting terminal to receiving terminal is divided into into k+1 equal portions.
2. the relevant OFDM decodings of FSO according to claim 1 forward serial optimal location relay,
Characterized in that, the transmitting terminal includes the first low pass filter (1), the first frequency mixer (2), the filter of the first band logical being sequentially connected
Ripple device (3), the first Mach-Zehnder modulators (5), the first optical band pass filter (6) and the first transmitting antenna (7)；Described
One Mach-Zehnder modulators (5) are also associated with first laser device (4).
3. the relevant OFDM decodings of FSO according to claim 1 forward serial optimal location relay,
Characterized in that, the DF via nodes include be sequentially connected the first reception antenna (8), the first magnitude amplifier (9), first
Optical mixer unit (10), the second optical band pass filter (12), the first photodetector (13), the second bandpass filter (14), second
Frequency mixer (15), the second low pass filter (16), OFDM transmitter modules (17), the 3rd low pass filter (18), three-mixer
(19), the 3rd bandpass filter (20), the second Mach-Zehnder modulators (22), the 3rd optical band pass filter (23), second
Penetrate antenna (24)；Second laser (11) is also associated with first optical mixer unit (10), second Mach-Zehnder is adjusted
The 3rd laser instrument (21) is also associated with device (22) processed.
4. the relevant OFDM decodings of FSO according to claim 1 forward serial optimal location relay,
Characterized in that, the receiving terminal includes the second reception antenna (25), the second magnitude amplifier (26), the second light being sequentially connected
Frequency mixer (27), the 4th optical band pass filter (29), the second photodetector (30), the 4th bandpass filter (31), the 4th mix
Frequency device (32) and the 4th low pass filter (33)；The 4th laser instrument (28) is also associated with second optical mixer unit (27).
5. the relevant OFDM decodings of FSO according to claim 1 forward serial optimal location relay,
Characterized in that, the length per equal portions is not more than a km.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621267116.2U CN206181027U (en) | 2016-11-22 | 2016-11-22 | Optimum position relay of serial is forwardded in relevant OFDM decoding of free space optical communications |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621267116.2U CN206181027U (en) | 2016-11-22 | 2016-11-22 | Optimum position relay of serial is forwardded in relevant OFDM decoding of free space optical communications |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111565070A (en) * | 2019-05-29 | 2020-08-21 | 南京大学 | Free space optical signal transmission method and free space optical signal transmission device |
| CN112564795A (en) * | 2020-12-09 | 2021-03-26 | 中国计量大学 | MIMO-OSTBC parallel relay free space optical communication system and method based on GFDM |
-
2016
- 2016-11-22 CN CN201621267116.2U patent/CN206181027U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111565070A (en) * | 2019-05-29 | 2020-08-21 | 南京大学 | Free space optical signal transmission method and free space optical signal transmission device |
| CN112564795A (en) * | 2020-12-09 | 2021-03-26 | 中国计量大学 | MIMO-OSTBC parallel relay free space optical communication system and method based on GFDM |
| CN112564795B (en) * | 2020-12-09 | 2022-01-14 | 中国计量大学 | MIMO-OSTBC parallel relay free space optical communication system and method based on GFDM |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170517 Termination date: 20191122 |
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| CF01 | Termination of patent right due to non-payment of annual fee |