CN1953357A

CN1953357A - System, methods, and apparatuses for fine-sensing modules

Info

Publication number: CN1953357A
Application number: CN 200610152846
Authority: CN
Inventors: 禹王命; 李彰浩; 李贞硕; 金学善
Original assignee: Samsung Electro Mechanics Co Ltd
Current assignee: Samsung Electro Mechanics Co Ltd
Priority date: 2005-10-21
Filing date: 2006-10-20
Publication date: 2007-04-25

Abstract

Systems, methods, and apparatuses are provided for fine-sensing modules that are operative for identifying one or more signal types from an input radio frequency (RF) signal. The fine-sensing modules may include a multiplier that combines an RF input signal and a delayed RF input signal to produce a correlation signal and an integrator that receives the correlation signal from the multiplier, where the integrator determines correlation values from integrating the correlation signal. The fine-sensing module also includes a comparator in communication with the integrator that compares the correlation values to one or more thresholds to generate information indicative of at least one signal feature of the RF input signal.

Description

The system, method and the device that are used for fine-sensing modules

The cross reference of related application

The application requires in the U.S. Provisional Application the 60/729th of being entitled as of submitting on October 21st, 2005 " Systems; Methods, and Apparatuses for Fine-Sensing Modules, ", No. 034 priority, its full content is hereby expressly incorporated by reference.In addition, the present invention relates to the U. S. application of following unsettled jointly, common transfer, its full content is hereby expressly incorporated by reference: the application of submitting on July 18th, 2006 that is entitled as " Systems; Methods; andApparatuses for Spectrum-Sensing Cognitive Radios " the _ _ _ _ number and the application that is entitled as " Systems; Methods, andApparatuses for Coarse-Sensing Modules " submitted on July 18th, 2,006 the _ _ _ _ _ _ _ _ number.

Technical field

Generally speaking, the present invention relates to radio communication, more specifically, relate to the system, method and the device that are used for from one or more signal types of input radio frequency (RF) signal identification.

Background technology

In the U.S. and many other countries,, need with the entity of realization such as commercial, place, national government and individual communication as the frequent use of managing and distributing radio spectrum of the management group of FCC (Federal Communications Committee).More specifically, FFC is that entity and individual's (" licensee ") of commerce or government utility permits many wavelength coverages.These are licensed can to have patent rights, to utilize their licensed separately wavelength coverage in the special time amount in concrete area.The wavelength coverage of this permission is thought necessary, to prevent or to eliminate interference with other source.Yet if do not use specific wavelength coverage (" usable spectrum ") in specific time certain location, another device can utilize this usable spectrum to communicate.The utilization of this usable spectrum helps radio spectrum or its part to use more effectively.

Previous being used for of disclosing determines that the spectrum-sensing technology of usable spectrum meets obstructions, and this is because at least two reasons: (1) they can not under the sophisticated signal form, work or (2) they require too high hardware performance and/or calculate power consumption.For example, disclosed a kind of spectrum-sensing technology, wherein, incoherent energy detector is carried out the calculating of the Fourier transform (FFT) of arrowband input signal.FFT provides the spectrum component of arrowband input signal, and this spectrum component compares to detect significant signal with intended threshold level (threshold level) subsequently and receives.Yet noise level unknown and that change can produce intense influence to this intended threshold level.In addition, energy detector can not be distinguished the difference between modulation signal, noise and the interference signal.Therefore, it can not work under the sophisticated signal form such as spread spectrum signal, frequency hopping and multi-carrier modulation.

As another example, disclosed the cyclostationary characteristic detection technique, as the spectrum-sensing technology of the cycle specificity that adopts modulation signal, sinusoidal carrier, periodic pulse train, repeat frequency hopping pattern, cyclic prefix (cyclic prefix) etc.Calculate the frequency spectrum correlation function, to detect such as modulation type, symbol rate and to disturb the signal characteristic that exists.Because detection range and frequency resolution are compromised, so the digital system upgrading is unique method of improving the detection resolution of wideband input signal frequency spectrum.Yet this digital system upgrading requires too high hardware performance and calculates power consumption.In addition, flexible or extendible (scalable) detection resolution is unavailable under the immovable situation of hardware.

Therefore, industrial needs a kind of being used for makes hardware and the minimized fine-sensing modules of power consumption demand simultaneously from one or more signal types of input radio frequency (RF) signal identification.

Summary of the invention

According to embodiments of the invention, a kind of fine-sensing modules is provided, it is used for from one or more signal types of input radio frequency (RF) signal identification.For example, this fine-sensing modules can detect and the relevant spectrum occupancy of communicating by letter by the various general and emerging wireless standard that comprises IS-95, WCDMA, EDGE, GSM, Wi-Fi, Wi-MAX, Zigbee, bluetooth, digital TV (ATSC, DVB) etc.

Fine-sensing modules can be incorporated the part as cognitive radio into, although other embodiment can use fine-sensing modules in other wireless device and system.As described herein, fine-sensing modules can realize simulating auto-correlation (AAC) function, and it can obtain from the similitude between two signals (that is, correlation) amount, although also can use other optional mode.

According to embodiments of the invention, provide a kind of radio frequency (RF) spectrum-sensing system.This system comprises: multiplier combines the RF input signal, to generate coherent signal with the RF input signal of delay; And integrator, receive coherent signal from multiplier, wherein, integrator is determined correlation by coherent signal being carried out integration.This system also comprises comparator, and itself and integrator communicate, and correlation and at least one threshold value is compared, to generate the information of at least one signal characteristic of representing the RF input signal.

According to an aspect of the present invention, at least one signal characteristic can comprise the modulation type of RF input signal and at least one in the frame structure.According to a further aspect in the invention, the delay of the RF input signal of reconfigurable delay.According to a further aspect in the invention, integrator can be the sliding window integrator.According to another aspect of the invention, this system also comprises the analog to digital converter that is used for the digitlization correlation.According to a further aspect in the invention, the value of reconfigurable one or more threshold values.In accordance with a further aspect of the present invention, multiplier can multiply each other by the RF input signal with RF input signal and delay and generate coherent signal.

According to another embodiment of the present invention, the method that provides a kind of identification radio frequency (RF) frequency spectrum to use.This method comprises: receive the RF input signal; The RF input signal is postponed, to generate the RF input signal that postpones; And with the RF input signal combination of RF input signal and delay, to generate coherent signal.This method also comprises by coherent signal is carried out integration calculates correlation, and correlation and at least one threshold value are compared, to generate the information of at least one signal characteristic of representing the RF input signal.

According to an aspect of the present invention, relatively correlation can comprise correlation and at least one threshold value are compared to generate in the modulation type of representing the RF input signal and the frame structure information of at least one.According to a further aspect in the invention, this method also comprises the relevant delay of RF input signal that reconfigures and postpone.According to another aspect of the invention, calculating correlation can comprise by the sliding window integrator is applied to coherent signal and calculate correlation.According to a further aspect in the invention, this method also can comprise the information digitalization with at least one signal characteristic of expression RF input signal.According to a further aspect in the invention, this method also comprises the value that reconfigures at least one threshold value.In accordance with a further aspect of the present invention, the RF input signal in conjunction with RF input signal and delay can comprise that the RF input signal with RF input signal and delay multiplies each other.

According to still another embodiment of the invention, provide a kind of radio frequency (RF) spectrum-sensing device.This device comprises: antenna is used to receive the RF input signal; Postponement module postpones the RF input signal, to form the RF input signal that postpones; And multiplier, be used for RF input signal, to form coherent signal in conjunction with RF input signal and delay.This device also comprises: integrator is used for coherent signal is carried out integration to calculate correlation; And comparator, correlation and at least one threshold value are compared, import the information of at least one signal characteristic of radio signal to generate expression.

According to an aspect of the present invention, the delay of reconfigurable Postponement module.According to a further aspect in the invention, integrator can be the sliding window integrator.According to a further aspect in the invention, the value of reconfigurable at least one threshold value.According to another aspect of the invention, at least one signal characteristic can comprise the modulation type of RF input signal and at least one in the frame structure.According to a further aspect in the invention, multiplier can be used for the RF input signal of RF input signal and delay is multiplied each other.

Description of drawings

Now, describe the present invention with general terms with reference to the accompanying drawings, wherein, accompanying drawing does not need to draw in proportion, in the accompanying drawings:

Fig. 1 shows the functional block diagram according to the exemplary cognitive radio system of the embodiment of the invention;

Fig. 2 shows the exemplary process diagram of cognitive radio system among Fig. 1;

Fig. 3 shows according to the small echo pulse duration of the embodiment of the invention and the compromise between the small echo pulse frequency;

Fig. 4 A shows the block diagram of implementing (implementation) according to the exemplary multi-resolution spectrum sensing (MRSS) of the embodiment of the invention;

Fig. 4 B shows the example according to the extendible resolution control of the embodiment of the invention;

Fig. 5 A shows the waveform of two tonal signals (two-tone signal), and Fig. 5 B shows the corresponding frequency spectrum that will implement to detect by MRSS according to the embodiment of the invention;

Fig. 6 shows the waveform according to the small echo pulse train of the embodiment of the invention;

Fig. 7 A shows the I component waveform of I-Q sinusoidal carrier, and Fig. 7 B shows the Q component waveform according to the I-Q sinusoidal carrier of the embodiment of the invention;

Fig. 8 A shows the little wave impulse of modulation that obtains from the small echo generator according to the I component that utilizes the I-Q sinusoidal carrier of the embodiment of the invention;

Fig. 8 B shows the little wave impulse of modulation that obtains from the small echo generator according to the Q component that utilizes the I-Q sinusoidal carrier of the embodiment of the invention;

Fig. 9 A shows the related output signal waveform according to the input signal of the I component with I-Q sinusoidal carrier of the embodiment of the invention;

Fig. 9 B shows the related output signal waveform according to the input signal of the Q component with I-Q sinusoidal carrier of the embodiment of the invention;

Figure 10 A show according to the embodiment of the invention in given interval for the correlation of I component, by the sampled value that integrator and analog to digital converter obtained with I-Q sinusoidal carrier;

Figure 10 B show according to the embodiment of the invention in given interval for the correlation of Q component, by the sampled value that integrator and analog to digital converter obtained with I-Q sinusoidal carrier;

Figure 11 shows according to the detected exemplary frequency spectrum shape of the spectrum recognition module by in the MAC module of the embodiment of the invention;

Figure 12 to Figure 17 shows and implements the emulation of detected various signal formats according to the embodiment of the invention by MRSS;

Figure 18 shows the exemplary circuit diagram according to the coarse-sensing modules of the embodiment of the invention;

Figure 19 shows the functional block diagram according to the exemplary thin detection technology of the use AAC function of the embodiment of the invention;

Figure 20 A shows the example data OFDM symbol of following according to the lead code of the embodiment of the invention;

The AAC that will utilize that Figure 20 B shows according to the embodiment of the invention implements the frequency spectrum of the input IEEE802.11a signal of detection;

Figure 21 A shows input IEEE802.11a signal, and Figure 21 B shows the IEEE802.11a signal through postponing according to the embodiment of the invention;

Figure 22 shows according to the original input signal of the embodiment of the invention with through the waveform correlation between the signal that postpones;

Figure 23 shows the waveform that integrator generates that passes through according to the embodiment of the invention; And

Figure 24 shows the exemplary configurations according to the frequency agile radio front-end of the embodiment of the invention.

Embodiment

Below, the present invention is described with reference to the accompanying drawings more all sidedly, more shown in the drawings but not every embodiment.Certainly, these inventions can many different forms be implemented, and are not limited to embodiment described herein, on the contrary, provide these embodiment to make the disclosure satisfy applicable legal requiremnt.Label identical is in the whole text represented components identical.

Embodiments of the invention relate to cognitive radio system, method and the device that is used to adopt limited frequency spectrum source.Cognitive radio can allow surpass to cover the agreement of the wide frequency range of a plurality of mobile communication protocols and standard/or opportunistic spectrum share.According to the present invention, the embodiment of cognitive radio can detect the use of radio-frequency spectrum Mid Frequency intelligently and promptly utilize any interim no wavelength coverage, and does not disturb the communication between other authorized user.The use of these cognitive radios allows multimachine kind wireless network (for example, using different communication protocol, frequency etc.) coexistence each other.These wireless networks can comprise cellular network, Wireless Personal Network (PAN), WLAN (wireless local area network) (LAN) and wireless MAN (MAN).These wireless networks also can coexist with the TV network that comprises digital TV network.To one skilled in the art, can utilize the network of other type according to the present invention.

A. the system survey of cognitive radio

Fig. 1 shows the functional block diagram according to the exemplary cognitive radio system of the embodiment of the invention.Particularly, Fig. 1 shows cognitive radio 100, and it comprises antenna 116, emission/receiving converter 114, radio front-end 108, simulation broader frequency spectrum sensing module 102, analog to digital converter 118, signal processing module 126 and media interviews control (MAC) module 124.

Cognitive radio system run duration in conjunction with Fig. 1 of the flow chart description of Fig. 2 can pass through antenna 116 received RFs (RF) input signal.In exemplary embodiment of the present invention, antenna 116 can be surpass may be from several megahertzes (MHz) to several GHzs (GHz) scope the still exercisable broad-band antenna of wide frequency range.The input signal that is received by antenna 116 can be transmitted, or offers simulation broader frequency spectrum sensing module 102 (pieces 202) by emission/receiving converter 114.The spectrum-sensing module can comprise one or two in coarse-sensing modules 104 and the fine-sensing modules 106.Name as them is represented, coarse-sensing modules 104 (for example can detect suspicious wavelength coverage, the wavelength coverage that may utilize) appearance or existence, and fine-sensing modules 106 can be scrutinized or analyze the suspicious wavelength coverage that is detected, with concrete signal type and/or the modulation scheme of determining wherein to utilize.

Again with reference to Fig. 2, coarse-sensing modules 104 can at first be determined the spectrum occupancy (piece 204) of the input signal that received.Spectrum occupancy information can be converted to digital form from analog form by modulus (A/D) transducer 118, and in exemplary embodiment of the present invention, analog to digital converter 118 can be low-speed a/d converter (ADC).The spectrum recognition module 120 that the digital spectrum occupation rate information that is provided by A/D converter 118 can be controlled by media interviews in (MAC) module 124 receives.Spectrum recognition module 120 can be to digital one or more calculating of spectrum occupancy information and executing, and whether one or more wavelength coverages are current is using or do not taken by others to discern.Spectrum recognition module 120 can hardware, software or their combination are implemented.

In some cases, based on the wavelength coverage of being discerned, MAC module 124 can ask more accurately to search for spectrum occupancy (piece 206).In this case, fine-sensing modules 106 can be used for being identified in concrete signal type and/or the modulation scheme of being utilized at least a portion of spectrum occupancy (piece 208).Then, can provide it to spectrum recognition module 120 then by the information of A/D converter 118 digitlization identification signal types and/or modulation scheme.Must determine the influence of the interference in the suspicious wavelength coverage that is detected about the information of signal type and/or modulation scheme.

According to embodiments of the invention, spectrum recognition module 120 can use database to compare (piece 210) information and the frequency spectrum from coarse-sensing modules 104 and/or fine-sensing modules 106, available to determine (for example, do not have occupied or safe) frequency spectrum groove (spectrumslot) (piece 212).Frequency spectrum use database can comprise the information about known signal type, modulation scheme and correlated frequency.Similarly, frequency spectrum uses database can comprise one or more being used for determine whether represent one or more threshold values that take frequency spectrum from the information of coarse-sensing modules 104 and/or fine-sensing modules 106.According to exemplary embodiment of the present invention, can upgrade frequency spectrum based on the information that receives from external source and use database, external source comprises periodic broadcasting form base station or other distant station, removable information stores (for example, removable chip, memory etc.), the Internet thesaurus.Alternatively, can based on inside or upgrade frequency spectrum based on the adaptive learning technology that can comprise test and error, test structure, statistical computation etc. and use database.

The sensing result of being determined by spectrum recognition module 120 can report to the controller (for example, the spectrum allocation may module) of MAC module 124, and asks the permission (piece 214) of specific frequency spectrum use.According to the approval of controller, the reconfiguring piece and can offer radio front-end 108 (piece 218) by signal processing module 126 of MAC module 124 with reconfiguring information.In exemplary embodiment of the present invention, radio front-end 108 can be reconfigured under different frequencies operation (" frequency agile "), and wherein, characteristic frequency or a plurality of frequency can be depending on the wavelength coverage that the signal post selected by cognitive radio 100 uses.Combine with the quick front end 108 of frequency, use to adapt to modulation and interference cancellation techniques, processing module 126 (can be the physical layer signal processing block in the exemplary embodiment) can strengthen the performance of cognitive radio 100.

In the case of without departing from the present invention, can make many modifications to cognitive radio 100.In optional embodiment, antenna 116 can comprise at least two antennas.First antenna can be used for radio front-end 108, and second antenna can be used for spectrum-sensing module 102.According to exemplary embodiment, the use of at least two antennas can be removed the necessity of the emission/receiving converter 114 between radio front-end 108 and the spectrum-sensing module 102.Yet, in another embodiment of the present invention, between the transmitter 110 of radio front-end 108 and receiver 112, still need emission/receiving converter 114.In addition, even do not move or be under the situation of holding state at radio front-end 108 and signal processing module 126, spectrum-sensing module 102, A/D converter 118, MAC module 124 still can be kept operation.Can reduce the power consumption of cognitive radio 100 like this, still allow cognitive radio 100 to determine spectrum occupancy simultaneously.

Describe cognitive radio 100 substantially, will describe the operation of the parts of cognitive radio 100 in further detail below.

B. spectrum-sensing parts

Still with reference to Fig. 1, according to exemplary embodiment of the present invention, spectrum-sensing module 102 can comprise coarse-sensing modules 104 and fine-sensing modules 106.Yet if desired, other embodiments of the invention can only be utilized in spectrum-sensing module 102 or the coarse-sensing modules 104.In addition, although the parts of spectrum-sensing module 102 as exemplary cognitive radio 100 are shown, this spectrum-sensing module 102 can be provided in the different devices, and with acting on the effective ways of determining usable spectrum in the optional application.These optional application can comprise Wireless Personal Network (PAN), WLAN (wireless local area network) (LAN), radio telephone, cellular phone, Digital Television, mobile TV and global positioning system.

Now, with reference to the spectrum-sensing module 102 among Fig. 1, spectrum-sensing module 102 can comprise coarse-sensing modules 104 and fine-sensing modules 106, and they can be used simultaneously, to strengthen the accuracy of frequency spectrum detection performance by MAC module 124.In addition, according to embodiments of the invention, spectrum-sensing module 102 can be implemented in the analog domain that certain characteristics can be provided (analogdomain).For example, this spectrum-sensing module of implementing in analog domain 102 can provide fast detecting, low-power consumption and the low hardware complexity of wideband frequency range.Below, will the coarse-sensing modules 104 and the fine-sensing modules 106 of spectrum-sensing module 102 be described in further detail.

1. coarse-sensing modules

According to exemplary embodiment of the present invention, the wavelet transformation of the multiresolution sensed characteristic of the multi-resolution spectrum sensing (MRSS) known to providing can be provided coarse-sensing modules 104.The use of MRSS by coarse-sensing modules 104 can allow detection resolution flexibly, and does not require and increase the hardware load.

By MRSS, wavelet transformation can be applied to the signal of variable preset time, with definite given time variable signal with as the correlation between the function of wavelet transformation basis (for example, little wave impulse).According to embodiments of the invention, determined correlation can be known wavelet conversion coefficient, and it can analog in form be determined.According to embodiments of the invention, above-mentioned conduct may be changed or dispose by the small echo pulse on the applied wavelet conversion of MRSS basis by MAC module 124.Particularly, the little wave impulse that is used for wavelet conversion can and/or change on the cycle in bandwidth, carrier frequency.By changing small echo pulse bandwidth, carrier frequency and/or cycle, the spectral content that the wavelet conversion coefficient by given signal provides can be with extendible resolution or multi-resolution representation.For example, according to exemplary embodiment of the present invention, change them by keep small echo pulse duration and/or carrier frequency in specific interval after, wavelet conversion coefficient can provide the analysis to the spectral content of time variable signal.Similarly, according to exemplary embodiment of the present invention, the shape of configurable little wave impulse.

A. small echo pulse choice

Now, the selection of the suitable little wave impulse of using among the MRSS, the width of especially little wave impulse and carrier frequency will be described in further detail.Fig. 3 shows the small echo pulse duration (Wt) 302 that may consider and the compromise between the small echo pulse frequency (Wf) 304 (for example, being also referred to as " resolution bandwidth " herein) when selecting suitable small echo pulse.In other words, along with small echo pulse duration 302 increases, small echo pulse frequency 304 reduces usually.As shown in Figure 3, small echo pulse duration 302 can be inversely proportional to small echo pulse frequency 304.

According to embodiments of the invention, uncertain inequality (uncertaintyinequality) can be applied to the selection of small echo pulse duration (Wt) 302 and resolution bandwidth (Wf) 304.Usually, uncertain inequality is provided for the boundary of particular type small echo wavelet pulses pulse duration (Wt) 302 and resolution bandwidth (Wf) 304.Product at small echo pulse duration (Wt) 302 and resolution bandwidth (Wf) 304 may (that is, Wt * Wf 〉=0.5 under) the situation, can use uncertain inequality more than or equal to 0.5.In little wave impulse is under the situation of the little wave impulse of Gaussian, can reach equal.Therefore, according to uncertain inequality, for the little wave impulse of Gaussian, small echo pulse duration (Wt) 302 and resolution bandwidth (Wf) 304 can be selected as use in wavelet transformation, make their product equal 0.5.

Although described the little wave impulse of the Gaussian of exemplary embodiment in the above, but also can utilize the little wave impulse of other shape, comprise Hanning, Haar, Daubechies, Symlets, Coifets, Bior Spline, Reverse Bior, Meyer, DMeyer, Mexicanhat, Morlet, Complex Gaussian, Shannon, Frequency B-Spline and Complex Morlet wavelet families.

The block diagram that b.MRSS implements

Fig. 4 A shows the block diagram of exemplary multi-resolution spectrum sensing (MRSS) enforcement that comprises coarse-sensing modules 104.Particularly, coarse-sensing modules can receive the time variable RF input signal x (t) from antenna 116.According to exemplary embodiment of the present invention, before offering coarse-sensing modules 104, this RF input signal x (t) can amplify by amplifier 402.For example, amplifier 402 can be excitation driver, and it can be used for providing above the consistent of wide frequency ranges and gains.

With reference to the coarse-sensing modules 104 of Fig. 4 A, coarse-sensing modules 104 can be made up of simulation wavelet shapes generator 404, analog multiplier 406, analogue integrator 408 and timing clock 410.Timing clock 410 can provide small echo generator 404 and analogue integrator 408 employed timing signals.According to exemplary embodiment of the present invention, the simulation correlation can be provided in output place of analogue integrator 408, it can offer the analog to digital converter (ADC) 118 that can be low speed again.Digitized correlation at the output of ADC118 can offer medium access control (MAC) module 124.

Still with reference to Fig. 4 A, the small echo generator 404 of coarse-sensing modules 104 can be used for generating small echo pulse v (t) chain, and it is modulated to form small echo pulse w (t) chain of modulation.For example, small echo pulse v (t) chain can be with I with given local oscillator (LO) frequency and Q sinusoidal carrier F _LO(t) modulate.By I and Q sinusoidal carrier F _LO(t), the I component signal can be identical with the Q component signal amplitude but has the phase differences of 90 degree.Subsequently, can will multiply by time variable input signal x (t) by small echo pulse w (t) chain of the modulation of small echo generator 404 output or combine, export the simulation related output signal z (t) of analogue integrator 408 with formation to by analog multiplier 406 with it.Analogue integrator 408 is determined and output simulation correlation y (t).

Be associated with the small echo pulse v (t) that has based on the given spectral width of above-mentioned pulsewidth and resolution bandwidth at these simulation correlation y (t) of output place of analogue integrator 408.Again with reference to the coarse-sensing modules among Fig. 4 104, use I and Q sinusoidal carrier F _LO(t) small echo pulse v (t) is modulated, to form the small echo pulse w (t) of modulation.Can scan or regulate I and Q sinusoidal carrier F subsequently _LO(t) local oscillator (LO) frequency.By scans I and Q sinusoidal carrier F _LO(t), can be in the simulation correlation y (t) that exceeds spectral region (particularly, exceeding the spectral region of being concerned about) signal energy amplitude and the frequency values in variable input signal x detection time (t), thereby extendible resolution is provided.

For example, by using narrow wave impulse v (t) and LO frequency F _LO(t) big tuning step-length is implemented can quick and sparse mode to check the spectral range of non-constant width according to the MRSS of the embodiment of the invention.On the contrary, utilize wide small echo pulse v (t) and LO frequency F _LO(t) accurate adjustment can realize point-device frequency spectrum search.In addition, according to exemplary embodiment of the present invention, () bandpass filtering effect for example, the small echo pulse w (t) of modulation, this MRSS implements may not request any active filter that image carrier suppresses (image rejection) that is used for because window signal (window signal).Similarly, the hardware load (comprising high power consumption figures hardware load) that this MRSS is implemented minimizes.Fig. 4 B shows the example that uses this extendible resolution control of small echo pulse W (ω) in frequency domain.Particularly, Fig. 4 B shows input signal X (ω) and can multiply each other with the small echo pulse W (ω) of the resolution bandwidth with variation, to realize the extendible resolution control of various output correlation Y (ω).

Again with reference to Fig. 4 A, in case generate simulation correlation y (t) by analogue integrator 408, amplitude that then can be by analog to digital converter 118 digitlization correlation y (t) also offers MAC module 124.More specifically, can pass through analog to digital converter 118 digitlizations and the I of wavelet shapes and each the relevant synthetic simulation correlation y (t) in the Q component, and their amplitude is by MAC module 124 records.According to embodiments of the invention, if amplitude greater than specific threshold level, sensing scheme or utilize spectrum recognition module 120 in the MAC module 124 can determine that significant interference receives (for example, concrete detected spectrum occupancy) then.

The emulation that c.MRSS implements

To describe according to the multi-resolution spectrum sensing (MRSS) of the embodiment of the invention according to several Computer Simulations now and implement.Particularly, use two to transfer the emulation of (two-tone) signal x (t) object computer, wherein, in same magnitude but each tone (tone) is set under different frequencies.Two tone signals with different frequency and phase place can be expressed as x (t)=A ₁Cos (ω ₁T+ θ ₁)+A ₂Cos (ω ₂T+ θ ₂).Fig. 5 A shows the waveform of two tonal signal x (t), and Fig. 5 B shows the corresponding frequency spectrum that will implement to detect by MRSS according to the embodiment of the invention.

MRSS according to example simulation implements, (for example be used for Hanning window function that the MRSS of this example simulation implements, Wt * Wf=0.513) selected as the small echo window function, wherein, the small echo pulse duration Wt of small echo window function restriction small echo pulse v (t) and the selection of resolution bandwidth Wf.The Hanning window function uses in this emulation, because its relative simplicity of implementing according to reality.The Hanning small echo wavelet pulses pulse duration (Wt) 302 that the uncertain inequality of above-mentioned Wt*Wf=0.513 can illustrate below being used for and the calculating of small echo pulse frequency (Wf) 304 obtain:

W_{t}^{} = \frac{1}{E} {&Integral;}_{- \infty}^{\infty} t^{2} ν^{2} (t) dt

W_{t}^{} = \frac{1}{2 πE} {&Integral;}_{- \infty}^{\infty} ω^{2} | V (jω) |^{2} dω

= \frac{1}{E} {&Integral;}_{- π / ω_{p}}^{π / ω_{p}} t^{2} [1 + \cos (ω_{p} t)]^{2} dt

= \frac{1}{2 πE} {&Integral;}_{- \infty}^{\infty} ω^{2} | \frac{ω_{p}^{2}}{ω (ω_{p}^{2} - ω^{2})} \sin (\frac{ω_{π}}{ω_{p}}) |^{2} dω

= \frac{2 π^{2} - 15}{6 ω_{p}^{2}}

= \frac{ω_{p}^{2}}{3}

Fig. 6 shows the waveform of exemplary small echo pulse v (t) chain.Therefore, in exemplary embodiment of the present invention, can have the I and the Q sinusoidal carrier F of the window signal of forming by small echo pulse v (t) chain by modulation _LO(t) obtain modulating pulse w (t) chain by small echo generator 404.Particularly, can pass through w (t)=v (t) f _LO(t) obtain modulating pulse w (t), wherein, v (t)=1+mcos (ω _pT+ θ _p) and

f_{LO} (t) = Σ_{k = 1}^{K} \cos (k ω_{LO} t + Φ),

Φ=0 or 90 °.Fig. 7 A shows I-Q sinusoidal carrier F _LOThe waveform of I component (t), and Fig. 7 B shows I-Q sinusoidal carrier F _LOThe waveform of Q component (t).Fig. 8 A shows and utilizes I-Q sinusoidal carrier F _LO(t) the modulation small echo pulse w (t) that I component obtains from small echo generator 404.Similarly, Fig. 8 B shows and utilizes I-Q sinusoidal carrier F _LO(t) the modulation small echo pulse w (t) that Q component obtains from small echo generator 404.

Then, shown in Fig. 9 A and Fig. 9 B, each modulating pulse w (t) be multiply by time variable signal x (t), to generate synthetic simulation related output signal z (t) by analog multiplier 406.Particularly, Fig. 9 A shows for having I-Q sinusoidal carrier F _LOThe waveform of the related output signal z (t) of the input signal x (t) of I component (t), and Fig. 9 B shows for having I-Q sinusoidal carrier F _LOThe waveform of the related output signal z (t) of the input signal x (t) of Q component (t).Then, carry out integration, to obtain correlation y (t) for the input signal x (t) of I component with wavelet shapes w (t) and Q component by the synthetic waveform among 408 couples of Fig. 9 A of analogue integrator and Fig. 9 B.

Then, correlation y (t) is integrated by analogue integrator 408, and is sampled by analog to digital converter 118.Figure 10 A shows the correlation y (t) that has the I component of wavelet shapes w (t) in given interval for these, the sampled value y that is provided by analog to digital converter 118 _IFigure 10 B shows in given interval the correlation y (t) for the Q component with wavelet shapes w (t), the sampled value y that is obtained by analogue integrator 408 and analog to digital converter 118 _QThen, as according to an exemplary embodiment of the present invention

| y | = \sqrt{y_{l}^{2} (t) + y_{Q}^{2} (t)}

Shown in, MAC module 124 or its spectrum recognition module 120 are passed through these values (y _IAnd y _Q) root of making even calculates the size of these sampled values.The spectral shape that is detected by the spectrum recognition module in the MAC module 124 120 shown in Figure 11.As shown in figure 11, the expectation frequency spectrum shown in detected spectral shape and Fig. 5 B well mates, thus the identification of expression quite good detecting and expectation frequency spectrum.

Figure 12 to Figure 17 shows the emulation that exemplary MRSS implements the various signal formats that detected of passing through according to the embodiment of the invention.These signal formats can comprise GSM, EDGE, wireless microphone (FM), ATDC (VSB), 3G honeycomb-WCDMA, IEEE802.11a-WLAN (OFDM).Particularly, Figure 12 A shows the frequency spectrum of GSM signal, and Figure 12 B shows corresponding detection signal frequency spectrum.Similarly, Figure 13 A shows the frequency spectrum of EDGE signal, and Figure 13 B shows corresponding detection signal frequency spectrum.Figure 14 A shows the frequency spectrum of wireless microphone (FM) signal, and Figure 14 B shows corresponding detection signal frequency spectrum.Figure 15 A shows the frequency spectrum of ATDC (VSB) signal, and Figure 15 B shows corresponding detection signal frequency spectrum.Figure 16 A shows the frequency spectrum of 3G honeycomb (WCDMA) signal, and Figure 16 B shows corresponding detection signal frequency spectrum.Figure 17 A shows the frequency spectrum of IEEE802.11a-WLAN (OFDM) signal, and Figure 17 B shows corresponding detection signal frequency spectrum.It should be appreciated by those skilled in the art,, can implement to detect other signal format according to MRSS according to the enforcement of the embodiment of the invention.

The circuit diagram of d. thick sensing block

Figure 18 illustrates the exemplary circuit diagram of the coarse-sensing modules 104 shown in Fig. 4.More specifically, Figure 18 shows small echo generator 454, multiplier 456a and 456b and integrator 458a and 458b.Small echo generator 454 can be made up of small echo pulse generator 460, local oscillator (LO) 462, phase shifter 464 (for example, 90 ° of phase shifters) and multiplier 466a and 466b.Small echo pulse generator 460 can provide the width of definite small echo pulse v (t) and/or the envelope signal of shape.Use multiplier 466a,, modulate small echo pulse w (t) to generate I component with the I component that the LO frequency that is provided by LO462 is provided small echo pulse v (t).Similarly, use multiplier 466b, small echo pulse v (t) be multiply by Q component by the LO frequency of 90 ° of phase shifter 464 phase shifts, to generate Q component modulation small echo pulse w (t).

Then, each I component and Q component that multiplier 456a by separately and 456b will modulate small echo pulse w (t) multiply each other, to generate related output signal z separately _I(t) and z _Q(t).Then, integrator 458a by separately and 458b are to related output signal z _I(t) and z _Q(t) carry out integration, to generate correlation y separately _I(t) and y _Q(t).Though Figure 18 shows specific embodiment, it should be appreciated by those skilled in the art, can make many variations to the circuit diagram among Figure 18.

2. fine-sensing modules

According to exemplary embodiment of the present invention, the fine-sensing modules 106 among Fig. 1 can be used for discerning the periodic characteristic of each suspicious modulation format or the peculiar input signal of frame structure.These periodic characteristics can comprise sinusoidal carrier, periodic pulse train, cyclic prefix and lead code.More specifically, fine-sensing modules 106 can realize being used to discerning one or more correlation functions of these periodic characteristics of input signal.The input signal of being discerned can have the various sophisticated signal forms that adopted in the general and emerging wireless standard that comprises IS-95, WCDMA, EDGE, GSM, Wi-Fi, Wi-MAX, Zigbee, bluetooth, digital TV (ATSC, DVB) etc.

According to embodiments of the invention, the correlation function that fine-sensing modules 106 is implemented can be simulation auto-correlation (AAC) function.The AAC function can obtain two similitude (that is correlation) amounts between the signal.In other words, the correlation between the same waveform as produces maximum.Yet, because the data-modulated waveform has random character (because the primary signal on basis comprises random value), so can ignore the correlation between periodic signal waves and the data modulated signal waveform.On the contrary, the periodic characteristic of given signal (for example, modulation format or frame structure) has higher correlation, and it can be by the mark (signature) of AAC function utilization as the signal specific type.The signal specific type of being discerned by the AAC function in fine-sensing modules 106 can offer signal processing module 126, is used to eliminate interference effect.

The block diagram that a.AAC implements

Figure 19 shows the functional block diagram according to the exemplary fine-sensing modules 106 that utilizes the AAC function of the embodiment of the invention.Particularly, fine-sensing modules 106 can comprise analogue delay module 502, analog multiplier 504, analogue integrator 506 and comparator 508.According to embodiments of the invention, the simulation correlation that provides in output place of fine-sensing modules 106 can be digitized by the analog to digital converter 118 that can be low speed.

Now, with reference to the fine-sensing modules 106 of Figure 19, be delayed specific delays value T by analogue delay module 502 from the input rf signal x (t) of antenna 116 _dFor every kind of periodic signal form, the length of delay T that provides by analogue delay module 502 _dCan be predetermined and unique.For example, IEEE802.11a-WLAN (OFDM) signal can with the first length of delay T _D1Be associated, and 3G honeycomb (WCDMA) signal can be different from the first length of delay T _D1The second length of delay T _D2Be associated.

Can utilize analog multiplier 504 to pass through with two signals (original input signal x (t) and inhibit signal x (t-T _d)) multiply each other or combination, carry out original input signal x (t) and inhibit signal x (t-T _d) between simulation relevant, to form coherent signal.Then, carry out integration, to generate correlation by 506 pairs of coherent signals of analogue integrator.According to exemplary embodiment of the present invention, analogue integrator 506 can be sliding window (sliding-window) integrator.When from the correlation of integrator 506 greater than as during by comparator 508 determined certain threshold level, the signal specific type of original input signal can be discerned by the spectrum recognition module 120 of MAC module 124.According to embodiments of the invention, can be every kind of signal type predetermined threshold.These signal types can comprise IS-95, WCDMA, EDGE, GSM, Wi-Fi, Wi-MAX, Zigbee, bluetooth, digital TV (ATSC, DVB) etc.

Because the exemplary AAC among Figure 19 implements all signals in the treatment of simulated territory, so not only can allow real-time operation but also realize low-power consumption.By application delay T _dAnd thus input signal is got relevantly, can realize blind Detecting, and without any need for known reference signal.This blind Detecting can reduce to be used for hardware burden and/or the power consumption that reference signal is recovered significantly.In addition, according to embodiments of the invention, when implementing to provide together with above-mentioned MRSS, the AAC among Figure 19 implements to strengthen the spectrum-sensing performance.Particularly, in case when MRSS implement to detect the reception of suspicious interference signal, AAC implemented can check signal and discern its signal specific type based on its mark.

The emulation that b.AAC implements

According to embodiments of the invention, the AAC of Figure 19 implements and can carry out emulation to multiple signal type.As an example, IEEE802.11a-OFDM (orthogonal frequency division is multiplexing) signal can have synchronization preamble (synchronization preamble) through the beginning of the frame structure of being everlasting.For simply, shown in Figure 20 A, have only an example data OFDM symbol 522 to follow exemplary lead code (preamble) 551 is arranged.Figure 20 B shows and will implement the frequency spectrum of the IEEE802.11a signal that detected by AAC according to the embodiment of the invention.

Figure 21 A shows input IEEE802.11a signal x (t), and Figure 21 B shows the IEEE802.11a signal x (t-T of delay _d).Figure 22 shows as original input signal x (t) that output provided and inhibit signal x (t-T at multiplier 504 _d) between the waveform of correlation.Synthetic waveform correlation shown in Figure 22 can have lead code 551 continuously on the occasion of 554.The result of integrator 506 as shown in figure 23 can have the peak value 602,604 of the lead code 551 that is positioned at the IEEE802.11a frame structure.Simultaneously, the correlation of modulated data symbol 552 has random value 556, and it is left in the basket after simulateding integrator 506 integrations.By utilizing relatively predetermined threshold V of comparator 508 _ThWith synthetic waveform shown in Figure 23, the exemplary AAC among Figure 19 implements to determine the reception of IEEE802.11a-OFDM signal.

Can implement to carry out many modifications to the AAC that describes among Figure 19.In optional embodiment, carrying out and threshold value V by comparator 508 _ThComparison before, the output of integrator 506 can be by analog to digital converter 118 digitlizations.In the time analog to digital converter 118 can being shared between coarse-sensing modules 104 and the fine-sensing modules 106 in one embodiment, can be coarse-sensing modules 104 in other embodiments and fine-sensing modules 106 provides independent analog to digital converter respectively.Similarly, the multiplier 504 of fine-sensing modules 106 and integrator 506 can be identical or different with multiplier 406 and integrator 408 in the coarse-sensing modules 104.Can make many other changes to one skilled in the art.

C. signal processing piece

Again with reference to Fig. 1,, disclosed the signal processing module 126 that can be physical layer block according to exemplary embodiment of the present invention.Signal processing module 126 can provide Base-Band Processing, and this Base-Band Processing comprises the processing of one or more modulation and demodulation schemes.In addition, perhaps based on any interference signal of discerning, signal processing module 126 also can provide interference eliminated.In addition, perhaps at least in part based on usable spectrum, signal processing module 126 can be used for reconfiguring the radio front-end that comprises transmitter 110 and/or receiver 112.For example, signal processing piece scalable is used for the transmitting power control or the tuning filter that is used for receiver 112 of transmitter 110, to move in specific frequency range.Those skilled in the art can understand easily, if desired or the expectation, can provide other Base-Band Processing by signal processing module 126.

D. frequency agility radio front-end

Figure 24 shows the exemplary configurations according to the frequency agile radio front-end 108 of the embodiment of the invention.Particularly, the receiving unit of radio front-end 108 can comprise one or more tunable filters 702, broadband receiver 704 and one or more low pass filter 706.According to exemplary embodiment of the present invention, tunable filter 702 can comprise little wave producer and multiplier.If desired, broadband receiver 704 can comprise one or more frequency levels and one or more low-converter.In addition, the radiating portion of radio front-end 108 can comprise one or more low pass filters 708, wideband transmitter 710 and one or more power amplifier 712.If desired, wideband transmitter 710 also can comprise one or more frequency levels and one or more low-converter.In addition, broadband receiver 704 and transmitter 710 can communicate with adjustable signal generator 714.It should be appreciated by those skilled in the art that under the situation that does not deviate from the embodiment of the invention, the parts of radio front-end 108 can change.

As described in seeing figures.1.and.2 as the front, the digitalized data (for example, passing through ADC118) that MAC module 124 is handled from spectrum-sensing module 102 thinks that safe (for example, unappropriated or glitch-free) cognitive radio 100 chains distribute usable spectrum.In addition, MAC module 124 will reconfigure control signal and offer radio front-end 108, be used for the optimum dedicated radio link of dividing frequency.Then, radio front-end 108 according to its frequency agility operation will to move the RF frequency shift be the respective frequencies value.More specifically, one or two of tunable filter 702 and adjustable signal generator 714 can change their running frequency, to select the signal in the respective frequencies territory.Simultaneously, based on 124 control informations of MAC module, PHY signal processing module 126 can utilize and adapt to modulation and interference cancellation techniques enhancing switching performance.

For have in front description and relevant drawings in these inventions of the technological merit that presented, those skilled in the art can expect many modifications and other embodiment of the embodiment that this paper sets forth.Therefore, should be appreciated that the present invention is not used in the disclosed specific embodiment of restriction, so various modifications and other embodiment should be within the scope of the appended claims.Though this paper has used concrete term, they only are general and descriptive, rather than the purpose that is used to limit.

Claims

1. a radio frequency (RF) spectrum-sensing system comprises:

Multiplier, described multiplier combines the RF input signal with the RF input signal of delay, to generate coherent signal;

Integrator, described integrator receives described coherent signal from described multiplier,

Wherein, described integrator is determined correlation by described coherent signal being carried out integration; And

Comparator, described comparator and described integrator communicate, and described correlation and at least one threshold value are compared, to generate the information of at least one signal characteristic of representing described RF input signal.

2. system according to claim 1, wherein, described at least one signal characteristic comprises the modulation type of described RF input signal and at least one in the frame structure.

3. system according to claim 1 wherein, reconfigures the delay of the RF input signal of described delay.

4. system according to claim 1, wherein, described integrator is the sliding window integrator.

5. system according to claim 1 also comprises analog to digital converter, is used for the described correlation of digitlization.

6. system according to claim 1 wherein, reconfigures the value of one or more described threshold values.

7. system according to claim 1, wherein, multiplying each other by the RF input signal with described RF input signal and described delay generates described coherent signal.

8. discern the method that radio frequency (RF) frequency spectrum uses for one kind, comprising:

Receive the RF input signal;

Described RF input signal is postponed, to generate the RF input signal that postpones;

With the RF input signal combination of described RF input signal and described delay, to generate coherent signal;

By being carried out integration, described coherent signal calculates correlation; And

Described correlation and at least one threshold value are compared, to generate the information of at least one signal characteristic of representing described RF input signal.

9. method according to claim 8, wherein, more described correlation comprises described correlation and at least one threshold value compared, with one of at least information in the modulation type that generates the described RF input signal of expression and the frame structure.

10. method according to claim 8 also comprises reconfiguring the delay relevant with the RF input signal of described delay.

11. method according to claim 8 wherein, is calculated described correlation and is comprised by the sliding window integrator is applied to described coherent signal and calculate described correlation.

12. method according to claim 8 also comprises the described information digitalization with at least one signal characteristic of the described RF input signal of expression.

13. method according to claim 8 also comprises the value that reconfigures at least one threshold value.

14. method according to claim 8 wherein, comprises that in conjunction with the RF input signal of described RF input signal and described delay the RF input signal with described RF input signal and described delay multiplies each other.

15. a radio frequency (RF) spectrum-sensing device comprises:

Antenna is used to receive the RF input signal;

Postponement module postpones described RF input signal, to form the RF input signal that postpones;

Multiplier is used for the RF input signal in conjunction with described RF input signal and described delay, to form coherent signal;

Integrator is used for described coherent signal is carried out integration, to calculate correlation;

And

Comparator compares described correlation and at least one threshold value, to generate the information of at least one signal characteristic of representing described input radio signal.

16. device according to claim 15 wherein, reconfigures the delay of described Postponement module.

17. device according to claim 15, wherein, described integrator is the sliding window integrator.

18. device according to claim 15 wherein, reconfigures the value of at least one threshold value.

19. device according to claim 15, wherein, described at least one signal characteristic comprise in the described modulation type of described RF input signal and the frame structure one of at least.

20. device according to claim 15, wherein, described multiplier is used for the RF input signal of described RF input signal and described delay is multiplied each other.