CN203942591U - A kind of receiver system with cognitive function - Google Patents
A kind of receiver system with cognitive function Download PDFInfo
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- CN203942591U CN203942591U CN201420386864.7U CN201420386864U CN203942591U CN 203942591 U CN203942591 U CN 203942591U CN 201420386864 U CN201420386864 U CN 201420386864U CN 203942591 U CN203942591 U CN 203942591U
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Abstract
The utility model discloses a kind of receiver system with cognitive function, and RF front-end module connects digital circuit blocks through analog-to-digital conversion module.The utility model, by introduce numerically controlled RF preselection filter that can wide-band tuning at radio-frequency front-end, can effectively be avoided the harmonious wave interference of mirror image, and it is convenient to control.Meanwhile, frequency spectrum perception and cognitive user data receiver are merged to one, when can realizing frequency spectrum perception and data receiver, carry out, and can find timely the intervention of primary user's signal, avoid quiet period, improve communication efficiency.In addition, the utility model can also provide idle channel to cognitive user, and constantly monitors current idle channel.Can also, the in the situation that of constant local oscillator, carry out frequency spectrum perception to other subchannels in XMHZ, alternate channel is provided.In the time that primary user resumes mandate frequency range, the real-time switching that realizes idle channel of dynamic and intelligent.
Description
Technical field
The utility model belongs to communication technical field, is specifically related to a kind of receiver system with cognitive function.
Background technology
In modern communications, the bottleneck that lowly becomes the development of restriction wireless communication technology of the scarcity of frequency spectrum resource and spectrum management efficiency.And cognitive radio technology is a kind of effective means that solves current problem.Meanwhile, as a pith of people's amusement and recreation, in the time, there is a lot of idle frequency spectrums in terrestrial DTV (DVB-T) on frequency and space.By cognitive radio technology, cognitive user can be carried out data communication in unauthorized Digital Television idle frequency spectrum.
The utilization of terrestrial DTV idle frequency spectrum, first needs to determine by frequency spectrum perception the idle frequency spectrum of terrestrial DTV, then the idle frequency spectrum perceiving is distributed to cognitive user and is used.In cognitive radio networks, adopt special perception receiver and the scheme of data communication receiver, this has not only increased system complexity, and is unfavorable for the system integration.Therefore, propose a kind of receiver system simply with cognitive function and become a new direction of research.On this basis, the energy detection algorithm being widely adopted, although can realize the frequency spectrum perception of received terrestrial digital broadcasting frequency range.But in order to ensure the reliability of frequency spectrum perception, perception need to be used quiet period.In quiet period, cognitive user must be interrupted self transmission, thereby causes the discontinuous of transfer of data, affects communication efficiency.Moreover, how to build spectrum pool, dynamic intelligence provide idle spare channel for cognitive user, be also the problem that this receiving system need to solve.Also,, in the time that primary user resumes mandate frequency range, what cognitive user should be real-time carries out the continuous switching of interchannel.
In addition, for the wide-band scope of terrestrial DTV.In realizing wide-band covering, reduce mirror image and disturb harmonious wave interference, be also the emphasis that method of reseptance and system need to be considered.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of receiver system with cognitive function, it is the idle frequency spectrum of perception terrestrial DTV frequency range effectively, and distribute accordingly idle frequency range to carry out the data receiver of cognitive user by cognition, it possesses frequency spectrum perception and data receiver is parallel, multiple available channels are for subsequent use, high performance feature.
For addressing the above problem, the utility model is achieved through the following technical solutions:
There is a receiver system for cognitive function, mainly formed by RF front-end module, analog-to-digital conversion module and digital circuit blocks.The output of RF front-end module is connected with the input of analog-to-digital conversion module, and the output of analog-to-digital conversion module connects digital circuit blocks.Above-mentioned radio-frequency front-end comprises RF preselection filter, low noise amplifier, the first local oscillator, the first frequency mixer, band pass filter, amplifier, the second local oscillator, the second frequency mixer, intermediate-frequency filter and automatic gain controller.The DVB-T signal of outside input or cognitive user signal are sent into the input of RF preselection filter.The output of RF preselection filter is connected with an input of the first mixer module via low noise amplifier, the output of the first frequency mixer is input to the input of amplifier through band pass filter, the output of amplifier connects an input of the second frequency mixer, and the output of the second frequency mixer is connected with the input of automatic gain controller through intermediate-frequency filter.The first local oscillator connects another input of the first frequency mixer; The second local oscillator connects another input of the second frequency mixer.The output of automatic gain controller connects the input of modulus conversion module.Above-mentioned digital circuit blocks comprises the first digitally tunable filters, signature detection circuit, frequency spectrum memory, switching circuit, the second digitally tunable filters, digital down converter, demodulator, clock circuit and control unit.The output of analog-to-digital conversion module is divided into two-way, the input of one tunnel the first digitally tunable filters connection features testing circuit, the output of signature detection circuit connects frequency spectrum memory, the input of the output connection control unit of frequency spectrum memory, forms the perception link of DVB-T signal thus; Another road connects the input of the second digitally tunable filters through switching circuit, the output of the second digitally tunable filters connects the input of demodulator through digital down converter, and demodulator is to outside output cognitive user signal; Form thus the demodulation link of cognitive user signal.Clock circuit is connected with control unit, output connecting valve circuit, the second digitally tunable filters, digital down converter, the first digitally tunable filters, signature detection circuit, RF preselection filter, the first local oscillator and the outside cognitive user of control unit.Control unit is mainly under clock circuit control, coordinates the work of cognitive user, digital circuit blocks and RF front-end module.
In above-mentioned receiving system, described RF preselection filter is mainly by the first decoupling capacitor circuit, the first notch filter circuit, the first impedance matching circuit, three rank resonator filter circuit, Coupled Inductor Circuit, the second impedance matching circuit, the second notch filter circuit and the second decoupling capacitor the electric circuit constitute.The input of the first decoupling capacitor circuit receives the radiofrequency signal of outside input, the first decoupling capacitor circuit output input the input of the first impedance matching circuit through the first notch filter circuit; The positive output end of the first impedance matching circuit is connected with the positive input terminal of the second impedance matching circuit through three rank resonator filter circuit, and the negative output terminal of the first impedance matching circuit is connected with the negative input end of the second impedance matching circuit with Coupled Inductor Circuit and ground connection; The second impedance matching circuit connects the input of the second decoupling capacitor circuit through the second notch filter circuit, the output of the second decoupling capacitor circuit is connected with low noise amplifier.
In above-mentioned receiving system, described the first digitally tunable filters and the second digitally tunable filters all adopt the variable finite impulse response digital filter of coefficient.
In above-mentioned receiving system, described signature detection circuit is mainly made up of down-sampling circuit, delay circuit, conjugate multiplication circuit, sliding window summation circuit and decision circuit.The input of down-sampling circuit is connected with the first digitally tunable filters, the delayed circuit of output of down-sampling circuit connects the input of conjugate multiplication circuit, the output of conjugate multiplication circuit connects the input of decision circuit through sliding window summation circuit, the output of decision circuit is connected with frequency spectrum memory.
Think ratio with prior art, the utlity model has following characteristics:
1, introduce numerically controlled RF preselection filter that can wide-band tuning at radio-frequency front-end, can effectively avoid the harmonious wave interference of mirror image, it is convenient to control.
2, frequency spectrum perception and cognitive user data receiver are merged to one, when can realizing frequency spectrum perception and data receiver, carry out, and can find timely the intervention of primary user's signal, avoid quiet period, improve communication efficiency.
3, can provide idle channel to cognitive user, and constantly monitor current idle channel.Can also, the in the situation that of constant local oscillator, carry out frequency spectrum perception to other subchannels in XMHZ, alternate channel is provided.In the time that primary user resumes mandate frequency range, the real-time switching that realizes idle channel of dynamic and intelligent.
Brief description of the drawings
Fig. 1 Novel cognitive radio receiver structure block diagram.
Fig. 2 is that frequency range is divided schematic diagram.
Fig. 3 is RF preselection filter circuit figure.
Fig. 4 is that feature detection realizes block diagram.
Embodiment
A kind of receiver system with cognitive function as shown in Figure 1, is mainly made up of RF front-end module, analog-to-digital conversion module and digital circuit blocks.The output of RF front-end module is connected with the input of analog-to-digital conversion module, and the output of analog-to-digital conversion module connects digital circuit blocks.The utility model has been introduced digital adjustable RF preselection filter at the RF front-end module of front end.The effect of the RF preselection filter of RF front-end module is that received RF signal is carried out to preliminary election filtering, selected filtering bandwidth is the frequency sub-band bandwidth XMHZ of segmentation, can reduce so the harmonious wave interference of mirror image that system broad receives, and desired signal bandwidth is carried out to a preliminary election comparatively accurately.This receiving system adopts super-heterodyne architecture, taking XMHZ as frequency sub-band bandwidth, DVB-T frequency range is divided into x frequency sub-band.By RF preselection filter, signal is carried out the preliminary election filtering of XMHZ, moved fixing high intermediate frequency by the first frequency mixer again, through the high if bandpas filter filtering of XMHZ, down-convert the signals to Low Medium Frequency through the second frequency mixer again, after XMHZ Low Medium Frequency bandpass filtering, directly send into analog-to-digital conversion module (being A/D).Taking YMHZ as subchannel bandwidth, each frequency sub-band is divided into y sub-channels.The control unit of the digital circuit blocks of rear end can effectively control RF preselection filter and the first local oscillator is chosen frequency sub-band, and by the digitally tunable filters of controlling perception link, multiple channels in frequency sub-band are carried out to perception one by one, and utilize institute's perception to go out certain idle sub-channels to communicate.In the utility model preferred embodiment, selecting the band limits of DVB-T is 410-850MHZ, is divided into multiple frequency sub-band with X=40MHZ, and for the DVB-T signal of Y=8MHZ channel width, each frequency sub-band comprises again 5 sub-channels.Referring to Fig. 2.
Above-mentioned radio-frequency front-end comprises RF preselection filter, low noise amplifier, the first local oscillator, the first frequency mixer, band pass filter, amplifier, the second local oscillator, the second frequency mixer, intermediate-frequency filter and automatic gain controller.The DVB-T signal of outside input or cognitive user signal are sent into the input of RF preselection filter.The output of RF preselection filter is connected with an input of the first mixer module via low noise amplifier, the output of the first frequency mixer is input to the input of amplifier through band pass filter, the output of amplifier connects an input of the second frequency mixer, and the output of the second frequency mixer is connected with the input of automatic gain controller through intermediate-frequency filter.The first local oscillator connects another input of the first frequency mixer.The second local oscillator connects another input of the second frequency mixer.The output of automatic gain controller connects the input of modulus conversion module.
In the utility model preferred embodiment, RF preselection filter as shown in Figure 3, mainly by the first decoupling capacitor circuit, the first notch filter circuit, the first impedance matching circuit, three rank resonator filter circuit, Coupled Inductor Circuit, the second impedance matching circuit, the second notch filter circuit and the second decoupling capacitor the electric circuit constitute.The input of the first decoupling capacitor circuit receives the radiofrequency signal of outside input, the first decoupling capacitor circuit output input the input of the first impedance matching circuit through the first notch filter circuit; The positive output end of the first impedance matching circuit is connected with the positive input terminal of the second impedance matching circuit through three rank resonator filter circuit, and the negative output terminal of the first impedance matching circuit is connected with the negative input end of the second impedance matching circuit through Coupled Inductor Circuit and ground connection; The second impedance matching circuit connects the input of the second decoupling capacitor circuit through the second notch filter circuit, the output of the second decoupling capacitor circuit is connected with low noise amplifier.If decoupling capacitor main circuit is removed external disturbance.Notch filter circuit is guaranteed the Out-of-band rejection characteristic that RF preselection filter is good.Impedance matching circuit is realized the impedance matching of 50 ohm, filter and front and back end circuit, realizes maximizes power transmission.Coupled Inductor Circuit, for the coupling of three rank resonant circuits, is realized required filtering bandwidth.Select three rank resonator, filters in the situation that ensureing that stopband suppresses, guarantee wide-band tuning scope and the filtering bandwidth needing.This RF preselection filter is in the band limits of 410～850MHZ, and 3dB signal bandwidth 40MHZ, increases along with frequency increases slightly, the insertion loss of 5.5dB, and Insertion Loss fluctuation range 0.5dB in bandwidth, Out-of-band rejection reaches 50dB.The mirror image that can effectively suppress in frequency sub-band by this RF preselection filter disturbs harmonious wave interference, improves the quality that receives signal.
In the utility model, it is 250MHZ that the analog-to-digital conversion module of collection signal adopts the maximum sample rate of the ADS4129 of TI company.In the utility model preferred embodiment, the sample rate of analog-to-digital conversion module is chosen as 200MHZ.
Above-mentioned digital circuit blocks comprises the first digitally tunable filters, signature detection circuit, frequency spectrum memory, switching circuit, the second digitally tunable filters, digital down converter, demodulator, clock circuit and control unit.The output of analog-to-digital conversion module is divided into two-way, the input of one tunnel the first digitally tunable filters connection features testing circuit, the output of signature detection circuit connects frequency spectrum memory, the input of the output connection control unit of frequency spectrum memory, forms the perception link of DVB-T signal thus.Another road connects the input of the second digitally tunable filters through switching circuit, the output of the second digitally tunable filters connects the input of demodulator through digital down converter, and demodulator is to outside output cognitive user signal.Form thus the demodulation link of cognitive user signal.Clock circuit is connected with control unit, output connecting valve circuit, the second digitally tunable filters, digital down converter, the first digitally tunable filters, signature detection circuit, RF preselection filter, the first local oscillator and the outside cognitive user of control unit.Control unit is mainly under clock circuit control, coordinates the work of cognitive user, digital circuit blocks and RF front-end module.
In the utility model preferred embodiment, the first and second digitally tunable filters adopt variable FIR (finite impulse response (FIR)) digital filter of coefficient, adjustable by the control of filter coefficient being carried out to centre frequency, the digital filtering that bandwidth is certain.Finite Impulse Response filter, in ensureing that amplitude characteristic meets technical requirement, has strict linear phase, is applicable to being applied to native system.By the storage to filter coefficient in advance, can produce the variable many groups filter of the certain centre frequency of bandwidth.By the control of filter coefficient group selection signal, can select the filter coefficient needing to carry out corresponding refinement frequency range filtering work, realize the function of the numeral slip channel selection filtering needing.
In the utility model preferred embodiment, shown in signature detection circuit specific implementation block diagram 4, mainly formed by down-sampling circuit, delay circuit, conjugate multiplication circuit, sliding window summation circuit and decision circuit.The input of down-sampling circuit is connected with the first digitally tunable filters, the delayed circuit of output of down-sampling circuit connects the input of conjugate multiplication circuit, the output of conjugate multiplication circuit connects the input of decision circuit through sliding window summation circuit, the output of decision circuit is connected with frequency spectrum memory.Down-sampling circuit is transferred to base band by I/Q solution, reduces sampling rate.Delay circuit is realized the delay of signal significant character length.Conjugate multiplication circuit is realized the conjugate multiplication of inhibit signal and current input signal.Sliding window summation circuit is realized the data accumulation summation under Cyclic Prefix length of window.Decision circuit is set thresholding judgment signal.Feature detection adopts the characteristic detection method based on Cyclic Prefix correlation, and the method can effectively be identified DVB-T signal, facilitates again hardware to realize.
In the utility model preferred embodiment, by frequency spectrum memory, the X/8 sub-channels in frequency sub-band is stored, and constantly updated.Inquiry by control unit with select idle channel for demodulation link, effectively like this built small-sized spectrum pool, facilitate the real-time switching of channel.
In the utility model preferred embodiment, the centre frequency of the selected idle channel that the digital local oscillator of Digital Down Convert is controlled unit controls.
Claims (4)
1. there is a receiver system for cognitive function, mainly formed by RF front-end module, analog-to-digital conversion module and digital circuit blocks; The output of RF front-end module is connected with the input of analog-to-digital conversion module, and the output of analog-to-digital conversion module connects digital circuit blocks; It is characterized in that:
Above-mentioned radio-frequency front-end comprises RF preselection filter, low noise amplifier, the first local oscillator, the first frequency mixer, band pass filter, amplifier, the second local oscillator, the second frequency mixer, intermediate-frequency filter and automatic gain controller; The DVB-T signal of outside input or cognitive user signal are sent into the input of RF preselection filter; The output of RF preselection filter is connected with an input of the first mixer module via low noise amplifier, the output of the first frequency mixer is input to the input of amplifier through band pass filter, the output of amplifier connects an input of the second frequency mixer, and the output of the second frequency mixer is connected with the input of automatic gain controller through intermediate-frequency filter; The first local oscillator connects another input of the first frequency mixer; The second local oscillator connects another input of the second frequency mixer; The output of automatic gain controller connects the input of modulus conversion module;
Above-mentioned digital circuit blocks comprises the first digitally tunable filters, signature detection circuit, frequency spectrum memory, switching circuit, the second digitally tunable filters, digital down converter, demodulator, clock circuit and control unit; The output of analog-to-digital conversion module is divided into two-way, the input of one tunnel the first digitally tunable filters connection features testing circuit, the output of signature detection circuit connects frequency spectrum memory, the input of the output connection control unit of frequency spectrum memory, forms the perception link of DVB-T signal thus; Another road connects the input of the second digitally tunable filters through switching circuit, the output of the second digitally tunable filters connects the input of demodulator through digital down converter, and demodulator is to outside output cognitive user signal; Form thus the demodulation link of cognitive user signal; Clock circuit is connected with control unit, output connecting valve circuit, the second digitally tunable filters, digital down converter, the first digitally tunable filters, signature detection circuit, RF preselection filter, the first local oscillator and the outside cognitive user of control unit.
2. a kind of receiver system with cognitive function according to claim 1, is characterized in that:
Described RF preselection filter is mainly by the first decoupling capacitor circuit, the first notch filter circuit, the first impedance matching circuit, three rank resonator filter circuit, Coupled Inductor Circuit, the second impedance matching circuit, the second notch filter circuit and the second decoupling capacitor the electric circuit constitute;
The input of the first decoupling capacitor circuit receives the radiofrequency signal of outside input, the first decoupling capacitor circuit output input the input of the first impedance matching circuit through the first notch filter circuit; The positive output end of the first impedance matching circuit is connected with the positive input terminal of the second impedance matching circuit through three rank resonator filter circuit, and the negative output terminal of the first impedance matching circuit is connected with the negative input end of the second impedance matching circuit through Coupled Inductor Circuit and ground connection; The second impedance matching circuit connects the input of the second decoupling capacitor circuit through the second notch filter circuit, the output of the second decoupling capacitor circuit is connected with low noise amplifier.
3. a kind of receiver system with cognitive function according to claim 1, is characterized in that:
Described the first digitally tunable filters and the second digitally tunable filters all adopt the variable finite impulse response digital filter of coefficient.
4. a kind of receiver system with cognitive function according to claim 1, is characterized in that:
Described signature detection circuit is mainly made up of down-sampling circuit, delay circuit, conjugate multiplication circuit, sliding window summation circuit and decision circuit, the input of down-sampling circuit is connected with the first digitally tunable filters, the delayed circuit of output of down-sampling circuit connects the input of conjugate multiplication circuit, the output of conjugate multiplication circuit connects the input of decision circuit through sliding window summation circuit, the output of decision circuit is connected with frequency spectrum memory.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420386864.7U CN203942591U (en) | 2014-07-14 | 2014-07-14 | A kind of receiver system with cognitive function |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104092967A (en) * | 2014-07-14 | 2014-10-08 | 桂林电子科技大学 | Receiver system and receiving method with cognitive function |
| CN108024076A (en) * | 2016-10-25 | 2018-05-11 | 晨星半导体股份有限公司 | The signal processing apparatus and its signal processing method at television reception end |
| CN110034831A (en) * | 2019-02-25 | 2019-07-19 | 北京理工大学 | A kind of spectrum monitoring device and method of low complex degree |
-
2014
- 2014-07-14 CN CN201420386864.7U patent/CN203942591U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104092967A (en) * | 2014-07-14 | 2014-10-08 | 桂林电子科技大学 | Receiver system and receiving method with cognitive function |
| CN104092967B (en) * | 2014-07-14 | 2017-02-15 | 桂林电子科技大学 | Receiver system and receiving method with cognitive function |
| CN108024076A (en) * | 2016-10-25 | 2018-05-11 | 晨星半导体股份有限公司 | The signal processing apparatus and its signal processing method at television reception end |
| CN110034831A (en) * | 2019-02-25 | 2019-07-19 | 北京理工大学 | A kind of spectrum monitoring device and method of low complex degree |
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Granted publication date: 20141112 Effective date of abandoning: 20170215 |
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| AV01 | Patent right actively abandoned |