CN102413088B - For the method and apparatus detected that coexists - Google Patents

Abstract

The present invention proposes a kind of to take same channel transmission data communication system coexist detect method, comprising: calculate the first detection statistic according to Received signal strength; When described first detection statistic is not more than the first predetermined threshold, trigger the calculating of the second detection statistic; When described second detection statistic is not more than the second predetermined threshold, determine that channel is unoccupied, notice allows the transmission of payload data, wherein, one of described first detection statistic and described second detection statistic calculate according to the energy of described Received signal strength and noise variance; And another in described first detection statistic and described second detection statistic is according to calculating multiple characteristic values of the sample covariance matrix of described Received signal strength.The invention allows for a kind of to take same channel transmission data communication system coexist detect equipment.

Description

For the method and apparatus detected that coexists

Technical field

The present invention relates to the detection that coexists in communication system, more specifically, relate to coexist detection and the input in such as IP route.

Background technology

60GHz communication is a kind of emerging short-distance wireless communication technology, can support that gigabit transmits due to its larger bandwidth of operation (4 ~ 7GHz).At present, multiple specifications of the 60GHz millimeter wave WLAN (wireless local area network)/Wireless Personal Network (WLAN/WPAN) of the various application (such as, IEEE 802.15.3c, WirelessHD and WiGig etc.) about short haul connection have been established.Therefore, the detection that coexists for the different 60GHz system taking same frequency band becomes very important.

Two classes can be divided at present for the detection method that coexists in 60GHz system.One class is that energy measuring (ED) mode is (see H.Urkowits, " Energy detection of unknowndeterministic signals " in Processing of the IEEE, vol.55, Apr.1967, pp.523-531), another kind of is that the common mode defined in IEEE 802.15.3c detects (CMS) scheme.

Energy measuring (ED) becomes the most frequently used signal detecting method due to its simplicity and validity.But traditional ED is subject to the impact of incorrect noise, shows bad detection perform under low signal-to-noise ratio state, this phenomenon is more obvious under 60GHz channel condition.(see M.Park, E.Perahia and M.Gong, " Analysis on IEEE 802.15.3ccoexistence scheme " in IEEE 802.11-09/559r0, May 2009).

CMS relates to complicated control frame PHY/MAC layer to be coordinated, and thus in actual applications due to too complicated, cost is very high and be difficult to realize (see S.Kato, C.S.Sun, T.Baykas, Z.Lan, J.Wang, R.Funada, M.A.Rahman, C.W.Pyo, H.Harada and I.Lakkis, " Common mode signaling (CMS) for inter-system coexistenceenhancement " in IEEE 802.11-09-370-00-00ad, May 2009).

Therefore, need one to coexist detection mode, the traditional E D scheme used in current 60GHz system can be better than, and compared with CMS scheme, the complexity that control frame PHY/MAC layer is coordinated can be reduced.

Summary of the invention

The present invention proposes a kind of new two-stage for 60GHz millimeter wave (MMW) WLAN/WPAN to coexist detection scheme.Use energy detector to perform coarse scanning at first order place.If the signal busy channel existed from using the communication equipment of other communication standard to send detected, then avoid needing the equipment of transport payload data to transmit; Otherwise, call second level detector.At second level place, if detect that channel occupancy is empty, then allow to need the equipment of transport payload data to transmit; Otherwise, avoid transport payload data.

According to an aspect of the present invention, propose a kind of to take same channel transmission data communication system coexist detect method, comprising: calculate the first detection statistic according to Received signal strength; When described first detection statistic is not more than the first predetermined threshold, trigger the calculating of the second detection statistic; When described second detection statistic is not more than the second predetermined threshold, determine that channel is unoccupied, notice allows the transmission of payload data, wherein, one of described first detection statistic and described second detection statistic calculate according to the energy of described Received signal strength and noise variance; And another in described first detection statistic and described second detection statistic is according to calculating multiple characteristic values of the sample covariance matrix of described Received signal strength.

The method also comprises: when described first detection statistic is greater than described first predetermined threshold or when described second detection statistic is greater than described second predetermined threshold, determine that channel is occupied, send the notice of the transmission avoiding payload data.

Wherein said first predetermined threshold sets based on the distribution of known false alarm probability and described first detection statistic; And described second predetermined threshold sets based on the distribution of known false alarm probability and described second detection statistic.

Another in wherein said first detection statistic and described second detection statistic is logarithmic relationship with the arithmetic average of described multiple characteristic value and the ratio of geometric average.

Wherein the distribution of the first detection statistic and the second detection statistic meets the χ of the different degree of freedom ²distribution.

According to a further aspect in the invention, propose a kind of to take same channel transmission data communication system coexist detect equipment, comprise: the first detector, this first detector comprises: the first calculation element, for calculating the first detection statistic according to Received signal strength; And first compares judgment device, for when described first detection statistic is not more than described first predetermined threshold, trigger the calculating of the second detection statistic; And second detector, this second detector comprises: the second calculation element, for calculating the second detection statistic according to Received signal strength; And second compares judgment device, for when described second detection statistic is not more than the second predetermined threshold, determine that channel is unoccupied, notice allows the transmission of payload data, wherein, one of described first detection statistic and described second detection statistic calculate according to the energy of described Received signal strength and noise variance; And another in described first detection statistic and described second detection statistic is according to calculating multiple characteristic values of the sample covariance matrix of described Received signal strength.

Wherein, described first compares judgment device when determining that described first detection statistic is greater than described first predetermined threshold or described second compare judgment device when described second detection statistic is greater than described second predetermined threshold, determine that channel is occupied, send the notice avoiding payload data to transmit.

Wherein said first predetermined threshold sets based on the distribution of known false alarm probability and described first detection statistic: and described second predetermined threshold sets based on the distribution of known false alarm probability and described second detection statistic.

Another in wherein said first detection statistic and described second detection statistic is logarithmic relationship with the arithmetic average of described multiple characteristic value and the ratio of geometric average.

Wherein the distribution of the first detection statistic and the second detection statistic meets the χ of the different degree of freedom ²distribution.

The hierarchical detection scheme that the present invention proposes is in actual 60GHz channel, and its detection perform is better than traditional ED.And from the angle of computation complexity, the complexity that the PHY/MAC layer that the hierarchical detection scheme that the present invention proposes significantly reduces control frame compared to CMS is coordinated.

Accompanying drawing explanation

By reference to the accompanying drawings, above-mentioned and other side, feature and advantage of the present invention will become clearly from the following detailed description for non-limiting example of the present invention, wherein:

Fig. 1 shows the interference model of 60GHz WLAN/WPAN;

Fig. 2 shows two-stage according to an exemplary embodiment of the present invention and to coexist the structured flowchart of checkout equipment; And

Fig. 3 shows two-stage according to an exemplary embodiment of the present invention and to coexist the flow chart of detection method.

Embodiment

Below with reference to accompanying drawing, exemplary embodiment of the present invention is described.In this exemplary embodiment, for 60GHz WLAN/WPAN system.But those skilled in the art are to be understood that; scope of the present invention is not limited to this; this exemplary embodiment is only for describing object; should be regarded as example of the present invention but not any limitation of the invention; any communication system being operated in same frequency is all suitable for the solution of the present invention, thus all falls within the scope of protection of the present invention.

Fig. 1 shows and can apply example communication system 60GHzWLAN/WPAN 100 of the present invention.In this 60GHz WLAN/WPAN 100, exemplarily gone out two WLAN, each WLAN comprises a WLAN controller and multiple 60GHz equipment.These two WLAN are operated in identical frequency band, but use different 60GHz standards.Such as, WLAN1 uses WiGig, WLAN2 to use IEEE 802.15.3c.Equipment 2A in WLAN2 and equipment 2B will produce interference by equipment 1C in WLAN1 and equipment 1D, figure 1 illustrates interference region.Before equipment in WLAN1 needs to set up communication link, first WPAN1 controller scans whole frequency spectrum.Because the equipment in WLAN1 and WLAN2 is operated in identical frequency band, if WLAN1 controller detects by coexisting and finds that transmission channel is occupied, then avoid needing the equipment of transport payload data to transmit, or reschedule this transmission neatly to disturb between minimization system.

Below in conjunction with Fig. 2, the coexist structure of checkout equipment of two-stage is according to an exemplary embodiment of the present invention described.

Fig. 2 shows two-stage according to an exemplary embodiment of the present invention and to coexist checkout equipment 200, comprise energy detector 201 and total blindness's detector 203, wherein energy detector 201 comprises the first calculation element 2011 and first and compares judgment device 2013, and total blindness's detector 203 comprises the second calculation element 2031 and second and compares judgment device 2033.Should be appreciated that for the sake of simplicity with clear, illustrate only two-stage in Fig. 2 and to coexist device related to the present invention in checkout equipment 200, and eliminate the description to known devices.

Two-stage according to the present invention coexists the detection that coexists that checkout equipment 200 may be used in 60GHz system, no matter is for single carrier (SC) 60GHz system, or multicarrier (such as, OFDM) 60GHz system.Below, to be applied as example in OFDM 60GHz system, composition graphs 3 describes two-stage according to the present invention and to coexist the process detected.

Fig. 3 shows two-stage according to an exemplary embodiment of the present invention and to coexist the flow chart of detection method 300.Here, two hypothesis H in statistics are applied to ₀and H ₁, wherein H ₀represent the hypothesis do not existed from the signal busy channel using the communication equipment of other communication standard to send; H ₁represent the hypothesis that there is such signal busy channel.

First, in step S301, the first calculation element 2011 being arranged in the energy detector 201 of the first order for received signal y to calculate corresponding energy measuring statistic T _eD.

As in the OFDM 60GHz system of application example, this Received signal strength y should be vector, supposes to observe y in N number of independent observation block of observed time period _n, wherein n=0 ..., N-1, each y _nbe the vector of M × 1, they are statistically separate.Use y _n=[y _n(0) ..., y _n(M-1)] ^trepresent y _nin M measured value, and to have

H ₀：y _n＝w _n，n＝0，...，N-1

H ₁：y _n＝x _n+w _n，n＝0，...，N-1

That is, at H ₀hypothesis under, the signal y received _nbe only the multiple Gaussian noise vector in system, each component wherein follows that average is zero, variance is σ ²multiple Gaussian Profile CN (0, σ ²); And at H ₁hypothesis under, the signal y received _nthe multiple Gaussian noise vector in system and the transmission signal x that will detect _nsum.Here x is supposed _nbe multiple Gauss's vector with zero-mean, its covariance matrix is expressed as R _x=E [x _nx _n ^h].

Particularly, in step S301, the first calculation element 2011 in energy detector 201 calculates test statistics T according to the following formula _eD

$T_{\mathrm{ED}}=2\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}\frac{{\left|\right|y_n\left|\right|}^2}{{\mathrm{\σ}}^2}---\left(1\right)$

Next in step S303, compare by first in energy detector 301 the energy test statistics T that judgment device 3013 will calculate _eDcompare with the predetermined threshold τ in energy measuring.

Predetermined threshold τ. with the false alarm probability P specifying during system to bear _f' and test statistics T _eDdistribution be correlated with.The decision-making value τ in energy measuring can be set in the following manner.

At H ₀when, T _eDfollow the χ that the degree of freedom is 2MN ²distribution.Therefore H ₀under T _eDcumulative density function (CDF) be

$F_{T_{\mathrm{ED}}|H_0}\left(x\right)=\frac{\mathrm{\Γ}(\mathrm{MN},x/2)}{\mathrm{\Γ}\left(\mathrm{MN}\right)},$

Wherein Γ () represents incomplete gamma functions, and Γ () represents gamma function.The false alarm probability P in energy measuring can be calculated according to the following formula _f'

${P_F}^{\′}=\mathrm{Pr}\{T_{\mathrm{ED}}>\mathrm{\τ}|H_0\}=1-F_{T_{\mathrm{ED}}|H_0}\left(\mathrm{\τ}\right)$

Therefore, for given P _f', the decision-making value τ that can obtain in energy measuring is

$\mathrm{\τ}={F^{-1}}_{T_{\mathrm{ED}}|H_0}(1-{P_F}^{\′})---\left(2\right)$

Wherein, be inverse function.

If first compares judgment device 3013 determine T in step S303 _eDbe greater than τ, then fall into H ₁in, can it is determined that the presence of the signal busy channel from using the communication equipment of other communication standard to send, so in step S311, first compares judgment device 3013 notice needs the equipment of transport payload data to avoid transmitting.

If first compares judgment device 3013 determine T in step S303 _eDbe not more than τ, then fall into H ₀in, can judge there is not the signal busy channel from using the communication equipment of other communication standard to send.Further, in step S305, first compares judgment device 3013 sends enable signal to total blindness's detector 203, and total blindness's detector 203 is worked.

In the present invention, utilize arithmetic average to geometric average detector (AGD) (see Y.Zeng and L.C.Liang " Eigenvalue-based spectrum sensing algorithm forcognitive radio " in IEEE Transactions on Communications, vol.57, Jun.2009, pp.1784-1793) realize the total blindness's detection being positioned at second level place.

The total blindness's detector AGD 203 being positioned at the second level strictly in accordance with generalized likelihood-ratio test (GLRT) example to derive test statistics T _aGD, and do not need R _xand σ ²any prior information (see R.Zhang, T.J.Lim, Y.C.Liang, and Y.Zeng " Multi-antennabased spectrum sensing for cognitive radios:a GLRT approach " in IEEETransactions on Communications, vol.58, Jan.2010, pp.84-88).AGD detects the inherent correlation (or rather, being the feature space of the sample covariance matrix of received data sampling) of received data sampling, thus has robustness for incorrect noise.

As shown in Figure 3, in step S307, the second calculation element 2031 being arranged in total blindness's detector AGD 203 of the second level, for received signal y, follows the formula of GLRT example derivation to calculate corresponding total blindness detection statistic T _aGD.As in the OFDM60GHz system of application example, this Received signal strength y should be vector, and the hypothesis of the energy measuring performed in the first order is similar, supposes to observe y in N number of independent observation block of observed time period _n, wherein n=0 ..., N-1, each y _nbe the vector of M × 1, they are statistically separate.Use y _n=[y _n(0) ..., y _n(M-1)] ^trepresent y _nin M measured value, and to have

H ₀：y _n＝w _n，n＝0，...，N-1

H ₁：y _n＝x _n+w _n，n＝0，...，N-1

Particularly, in step S307, the second calculation element 2031 in total blindness's detector AGD 203 is according to following the following formula of GLRT derivation to calculate test statistics T _aGD

$T_{\mathrm{AGD}}=K\·\ln \left[\frac{\frac{1}{M}{\mathrm{\Σ}}_{m=0}^{M-1}{\mathrm{\λ}}_m}{{\left({\mathrm{\Π}}_{m=0}^{M-1}{\mathrm{\λ}}_m\right)}^{1/M}}\right]---\left(3\right)$

Wherein K is multiplication factor, can be used for being modified in H ₀hypothesis under total blindness's test statistics T _aGDdistribution; λ _m={ λ _n..., λ _m-1descending, to y _nsample covariance matrix carry out M the characteristic value that Eigenvalues Decomposition obtains; with eigenvalue λ respectively _marithmetic average (AM) and geometric average (GM).

Next in step S309, compare by second in total blindness's detector AGD 303 the test statistics T that judgment device 3033 will calculate _aGDcompare with the predetermined threshold η during total blindness detects.

Predetermined threshold η is also. with the false alarm probability P specifying during system to bear _f" and test statistics T _aGDdistribution be correlated with.The decision-making value η in total blindness's detection can be set in the following manner.

As previously mentioned, multiplication factor K can be used for being modified in H ₀hypothesis under test statistics T _aGDdistribution.Here, can arrange to make T _aGDfollow the degree of freedom progressively for (M ²-1) χ ²distribution is (see W.S.Liggett, " Passive sonar:fitting models to multiple time series " in Processing of the NATO ASI onSignal Processing, J.W.R Griffiths and P.L.Stocklin, Eds.Academic Press:New York, 1973, pp.327-345).Can obtain thus, at H ₀under T _aGDcDF can be expressed as

$F_{T_{\mathrm{AGD}}|H_0}\left(x\right)=\frac{\mathrm{\Γ}(\frac{M^2-1}{2},\frac{x}{2})}{\mathrm{\Γ}\left(\frac{M^2-1}{2}\right)}$

Wherein Γ () represents incomplete gamma functions, and Γ () represents gamma function.The false alarm probability P in energy measuring can be calculated according to the following formula _f"

${P_F}^{\′\′}=1-F_{T_{\mathrm{AGD}}|H_0}\left(\mathrm{\η}\right)$

Therefore, for given P _f", the decision-making value η that can obtain in total blindness's detection is

$\mathrm{\η}={F_{T_{\mathrm{AGD}}|H_0}}^{-1}(1-{P_F}^{\′\′})---\left(4\right)$

Wherein, be inverse function.

If second compares judgment device 3033 determine T in step S309 _eDbe greater than η, then fall into H ₁in, can it is determined that the presence of the signal busy channel from using the communication equipment of other communication standard to send, so in step S313, second compares judgment device 3033 notice needs the equipment of transport payload data to avoid transmitting.

If second compares judgment device 3033 determine T in step S309 _eDbe not more than η, then fall into H ₀in, can judge there is not the signal busy channel from using the communication equipment of other communication standard to send, so in step S311, second compares judgment device 3033 notice needs the equipment of transport payload data to transmit.

Therefore, two-stage according to the present invention coexists detection scheme, if the energy detector 201 being in the first order has declared that channel is unoccupied mistakenly, the total blindness's detector 203 being so positioned at the second level can revise the judgement of this mistake.Compared with the scheme that carrying out with directly adopting total blindness's detector 203 coexists detects, the two-stage according to the present invention detection scheme that coexists reduces computation complexity, because only in the unappropriated situation of energy detector 201 reporting channel being positioned at the first order, just need to call total blindness's detector 203.

It will be appreciated by those skilled in the art that, although exemplary embodiment of the present invention is only described for the application in multicarrier (OFDM) 60GHz system, be also similar for the application in single carrier (SC) 60GHz system.

In addition, although exemplary embodiment of the present invention only describes realize for the energy detector by being in the first order and the total blindness's detector being in the second level detection that coexists, scope of the present invention is not limited to this.It will be understood by those skilled in the art that when not considering computation complexity, also can realize with the energy detector being in the second level detection that coexists by the total blindness's detector being in the first order.In this alternate embodiment, if use total blindness's detector the signal busy channel existed from using the communication equipment of other communication standard to send to be detected at first order place, then avoid needing the equipment of transport payload data to transmit; Otherwise, call the energy detector being positioned at the second level.At second level place, if detect that channel occupancy is empty, then allow to need the equipment of transport payload data to transmit; Otherwise, avoid transport payload data.

Those skilled in the art should be easy to recognize, can be realized the different step of said method by programmed computer.At this, some execution modes comprise equally machine readable or computer-readable program storage device (as, digital data storage medium) and encoding machine can perform or the executable program command of computer, wherein, this instruction performs some or all steps of said method.Such as, program storage device can be digital storage, magnetic storage medium (as Disk and tape), hardware or the readable digital data storage medium of light.Execution mode comprises the programmed computer of the described step performing said method equally.

Description and accompanying drawing only illustrate principle of the present invention.Therefore it should be appreciated that those skilled in the art can advise different structures, although these different structures clearly do not describe herein or illustrate, embody principle of the present invention and be included within its spirit and scope.In addition, all examples herein mentioned clearly main only for teaching purpose with the design of the promotion this area helping reader understanding's principle of the present invention and inventor and contribute, and should be interpreted as not being the restriction to these specific examples of mentioning and condition.In addition, herein all mention principle of the present invention, aspect and execution mode statement and specific example comprise its equivalent.

Claims (10)

1. to take same channel transmission data communication system coexist detect a method, comprising:

The first detection statistic is calculated according to Received signal strength;

When described first detection statistic is not more than the first predetermined threshold, trigger the calculating of the second detection statistic;

When described second detection statistic is not more than the second predetermined threshold, determine that channel is unoccupied, notice allows the transmission of payload data,

Wherein, one of described first detection statistic and described second detection statistic calculate according to the energy of described Received signal strength and noise variance; And another in described first detection statistic and described second detection statistic is according to calculating multiple characteristic values of the sample covariance matrix of described Received signal strength.

2. method according to claim 1, also comprise: when described first detection statistic is greater than described first predetermined threshold or when described second detection statistic is greater than described second predetermined threshold, determine that channel is occupied, send the notice of the transmission avoiding payload data.

3. method according to claim 1, wherein said first predetermined threshold sets based on the distribution of known false alarm probability and described first detection statistic: and described second predetermined threshold sets based on the distribution of known false alarm probability and described second detection statistic.

4. method according to claim 1, another in wherein said first detection statistic and described second detection statistic is logarithmic relationship with the arithmetic average of described multiple characteristic value and the ratio of geometric average.

5. method according to claim 1, wherein the distribution of the first detection statistic and the second detection statistic meets the χ of the different degree of freedom ²distribution.

6. to take same channel transmission data communication system coexist detect an equipment, comprising:

First detector, comprising:

First calculation element, for calculating the first detection statistic according to Received signal strength; And

First compares judgment device, for when described first detection statistic is not more than the first predetermined threshold, triggers the calculating of the second detection statistic;

Second detector, comprising:

Second calculation element, for calculating the second detection statistic according to Received signal strength; And

Second compares judgment device, for when described second detection statistic is not more than the second predetermined threshold, determines that channel is unoccupied, and notice allows the transmission of payload data,

Wherein, one of described first detection statistic and described second detection statistic calculate according to the energy of described Received signal strength and noise variance; And another in described first detection statistic and described second detection statistic is according to calculating multiple characteristic values of the sample covariance matrix of described Received signal strength.

7. equipment according to claim 6, wherein, described first compares judgment device when determining that described first detection statistic is greater than described first predetermined threshold or described second compare judgment device when described second detection statistic is greater than described second predetermined threshold, determine that channel is occupied, send the notice avoiding payload data to transmit.

8. equipment according to claim 6, wherein said first predetermined threshold sets based on the distribution of known false alarm probability and described first detection statistic: and described second predetermined threshold sets based on the distribution of known false alarm probability and described second detection statistic.

9. equipment according to claim 6, another in wherein said first detection statistic and described second detection statistic is logarithmic relationship with the arithmetic average of described multiple characteristic value and the ratio of geometric average.

10. equipment according to claim 6, wherein the distribution of the first detection statistic and the second detection statistic meets the χ of the different degree of freedom ²distribution.