CN102752865A - Method for distributing AP (access point) channels of mixed frequency range - Google Patents

Abstract

The invention discloses a method for distributing AP (access point) channels of a mixed frequency range. The method for distributing AP channels of the mixed frequency range includes distribution of channels of the ISM (industrial, scientific and medical) frequency range and access of an authorized frequency range in a cognitive radio manner and includes the following steps of firstly, computing interference areas of each AP, distributing weights to corresponding the APs according to a descending order of the proportion of the interference areas to the communication area; secondly, selecting the maximum undistributed AP weight, distributing the optimum channel to the maximum undistributed AP weight until all the AP channels are completely distributed; and thirdly, computing signal to interference ratio of each AP, comparing the signal to interference ratio with the threshold value guaranteeing the communication quality, finishing distribution if the signal to interference ratio is smaller than the threshold value, and distributing the authorized channels in case that the signal to interference ratio is larger than the threshold value and available channels in the authorized frequency range are left. By the method for distributing the AP channels of the mixed frequency range, channel distribution of the APs under high-density deployment is optimized, the available channels in the ISM frequency range and the authorized frequency range are sufficiently used, and throughput of the system is increased.

Description

A kind of mixing band A P method for channel allocation

Technical field

The present invention designs and mixes band A P channel allocation technique, particularly relates to ISM band and authorizes frequency range mixed channel distribution method.

Background technology

At present; Along with people's is to the surge of multimedia service demand; Cellular communication (2G/3G network) can not have been satisfied user's demand well, and characteristics such as wireless lan (wlan) possesses two-forty, be prone to dispose, cost is low obtain the approval of mobile operator; Each big operator disposes wireless aps in the big hot spot region of the density of population, and WLAN is regarded as the most effectively means of 2/3G data distribution.

But because deployment and the channel management scheme of the commercial WLAN of present lack of uniform; The shared channel configuration appears in the wireless aps that each big operator disposes in same hot spot region situation is very serious; When channel disturbance is serious, even the interruption of telex network can appear.It is thus clear that, solve the channel disturbance problem of wireless aps in the hot spot region effectively, be one of extensive commercial WLAN key technology of disposing.

The method that solves the wireless aps channel disturbance mainly contains two kinds; A kind of is to be that AP is at the suitable channel of unauthorized frequency allocation in the ISM/UNII of wireless aps work frequency range through methods such as graph coloring, integral linear programming, minimum spanning trees; Make overall interference minimum; But because the finiteness of WLAN channel itself, when facing the wireless aps of the same area high-density deployment, disturbed condition still can not get effective improvement.Another kind is through cognitive radio technology, inserts the not high mandate frequency range of utilance, expands the working frequency range of wireless aps, increases available channel.This field, up to the present, the achievement of research is also very few, that is to say, let based on the not high free time mandate frequency range of the cognition network access utilance of WLAN, also has a large amount of technical problems to capture.

Summary of the invention

In order to overcome the deficiency of above-mentioned prior art, the invention provides a kind of mixing frequency range AP method for channel allocation based on minimum signal interference ratio, make full use of ISM band and authorize the resource of frequency range, increase the wireless communication system resource utilization, improve network throughput.

The technical scheme that the present invention adopted is:

1) based on the weight calculation of confusion area, its process is following:

1.1) according to adjacent AP _iCommunication radius r ₁And AP _jThe interference radius r ₂, calculate AP _iCommunication zone and AP _jThe overlapping area of interference region, said area computation method is following:

$A_{\mathrm{ij}}=\left\{\begin{array}{cc}\frac{1}{2}{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2[{\mathrm{\&theta;}}_1-\sin \left({\mathrm{\&theta;}}_1\right)]+\frac{1}{2}{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_2^2[{\mathrm{\&theta;}}_2-\sin \left({\mathrm{\&theta;}}_2\right)],& d_{\mathrm{ij}}<{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_2\\ 0,& d_{\mathrm{ij}}\&GreaterEqual;{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+r_2\end{array}\right.---\left(1\right)$

Wherein, d _IjBe AP _iWith AP _jBetween distance, θ ₁Be AP _iThe central angle of lap, θ ₂Be AP _jThe central angle of lap;

1.2) calculate each AP and other AP overlapping area sum, it is compared with the area of communicating by letter, obtain the AP weight, said computational methods are following:

$W_i=\frac{\underset{j=1,j\&NotEqual;i}{\overset{N}{\mathrm{\&Sigma;}}}{A}_{\mathrm{ij}}}{{\mathrm{\&pi;<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2}---\left(2\right)$

Wherein, N is the AP number;

2) based on the mixing frequency range channel allocation of signal interference ratio, its process is following:

2.1) according to the power spectral density calculating channel isolation of signal on the ISM band channel, said channel isolation computational methods are following:

$\mathrm{\&phi;}(c_i,c_j)={\&Integral;}_{-\&infin;}^{+\&infin;}{S}_t\left(f\right)S_r(f-\mathrm{\&tau;})\mathrm{df}---\left(3\right)$

Wherein, c _iBe to distribute to AP _iChannel, c _jBe to distribute to AP _jChannel, S _t(f) expression AP transmission power distribution, S _r(f) expression AP received power distributes, and τ is AP _iAnd AP _jOffset frequency between the channel overlap;

2.2) combining channel isolation and overlapping region, the computational methods of signal interference ratio are following:

${\mathrm{SIR}}_i=\frac{{\mathrm{\&pi;<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2}{\underset{j=1,j\&NotEqual;i}{\overset{N}{\mathrm{\&Sigma;}}}\mathrm{\&phi;}(c_i,c_j)A_{\mathrm{ij}}}---\left(4\right)$

With the signal interference ratio of each AP and its threshold ratio, authorize frequency range whether to have available channel if exist signal interference ratio then to investigate greater than the situation of threshold value;

2.3) authorize the frequency range channel-aware, its process is following:

$\underset{\{r_j,x_j\}}{\max }\underset{j=\mathrm{0,1}}{\mathrm{\&Sigma;}}{\mathrm{\&pi;}}_j{r}_j\mathrm{Pr}\{r_j\&le;{\log }_2[1+\frac{x_j{g}_{\mathrm{ss}}}{(1-z_j){\mathrm{Yg}}_{\mathrm{ps}}+n}\left]\right\}$

$s.t.\underset{j=\mathrm{0,1}}{\mathrm{\&Sigma;}}{\mathrm{\&pi;}}_j{x}_j\&le;{\mathrm{\&Gamma;}}_1---\left(5\right)$

$\underset{j=\mathrm{0,1}}{\mathrm{\&Sigma;}}{\mathrm{\&pi;}}_j{\mathrm{\&alpha;}}_{0j}{x}_j{g}_{\mathrm{sp}}\&le;{\mathrm{\&Gamma;}}_2$

Wherein, π ₀The expression sensing results is for authorizing the probability of frequency range channel busy, π ₁The probability of expression sensing results for authorizing the frequency range channel to use, r ₁, x ₁The state of secondary user when the frequency range channel idle is authorized in expression, g _SsBe the channel power gain of secondary user's transmitted from transmitter to receiver, g _PsBe of the gain of main user transmitter to secondary user's receiver, g _SpBe the gain of secondary user's transmitter to main receiver user, z _jFrequency range channel busy, z are authorized in=0 expression _j=1 expression authorizes the frequency range channel can use α _IjIt is i and sensing results is the posterior probability of j, Γ that the frequency range virtual condition is authorized in expression back ₁Be secondary user's power maximum, Γ ₂Be the interference threshold of secondary user to main user.

Compared with prior art; The invention has the beneficial effects as follows: to the many disturbed conditions under the high density AP deployment scenario; Propose to mix the frequency range channel allocation algorithm; When communication quality does not reach when requiring with cognitive radio mode insertion authority frequency range, can effectively utilize radio spectrum resources, improve throughput of wireless networks.

Description of drawings

Fig. 1 is communication zone and interference region lap;

Fig. 2 is the ISM band channel situation;

Fig. 3 is an ISM band signal power spectrum density;

Fig. 4 is an ISM band channel allocation flow process;

Fig. 5 is for mixing frequency range channel allocation flow process.

Embodiment

Below in conjunction with accompanying drawing the present invention is further specified.

With reference to Fig. 1～Fig. 5, a kind of mixing band A P method for channel allocation, said method for channel allocation may further comprise the steps:

1) like Fig. 1, by AP communication zone and the overlapping area of closing on the AP interference region, calculating channel divides the weight of timing AP, and its process is following:

1.1) according to adjacent AP _iCommunication radius r ₁And AP _jThe interference radius r ₂, calculate AP _iCommunication zone and AP _jThe overlapping area of interference region, said area computation method is following:

$A_{\mathrm{ij}}=\left\{\begin{array}{cc}\frac{1}{2}{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2[{\mathrm{\&theta;}}_1-\sin \left({\mathrm{\&theta;}}_1\right)]+\frac{1}{2}{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_2^2[{\mathrm{\&theta;}}_2-\sin \left({\mathrm{\&theta;}}_2\right)],& d_{\mathrm{ij}}<{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_2\\ 0,& d_{\mathrm{ij}}\&GreaterEqual;{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+r_2\end{array}\right.---\left(1\right)$

Wherein, d _IjBe AP _iWith AP _jBetween distance, θ ₁Be AP _iThe central angle of lap, θ ₂Be AP _jThe central angle of lap;

1.2) calculate each AP and other AP overlapping area sum, it is compared with the area of communicating by letter, obtain the AP weight, said computational methods are following:

$W_i=\frac{\underset{j=1,j\&NotEqual;i}{\overset{N}{\mathrm{\&Sigma;}}}{A}_{\mathrm{ij}}}{{\mathrm{\&pi;<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2}---\left(2\right)$

Wherein, N is the AP number;

2) like Fig. 4, based on the ISM band channel allocation of integral linear programming, its process is following:

2.1) judge and then carry out channel allocation if exist by the AP that whether has unallocated channel, otherwise finish the ISM band channel allocation;

2.2) search current AP what have have the AP of overlapping region with it:

(1) if having only one, then its channel allocation is following:

f _v＝(f _u+5)mod11 (3)

Wherein, f _vBe the centre frequency of current AP allocated channel, f _uCentre frequency for the AP channel that has the overlapping region with it;

(2) if there are the overlapping region in two AP and current AP, its channel allocation is following:

min(|f _v-f _u|，|f _v-f _w|)＝5 (4)

Wherein, f _vBe the centre frequency of current AP allocated channel, f _uBe the centre frequency of an AP channel having the overlapping region with it, f _wCentre frequency for another AP channel of having the overlapping region with it;

(3) if there are overlapping region (exist choosing more than three three of overlapping region maximum) in three AP and current AP, its channel allocation is following:

min(|f _v-f _u|，|f _v-f _w|，|f _v-f _y|)＝d (5)

Wherein, f _u, f _w, f _yBe respectively the centre frequency of three AP channels, d from 5 to 1 values are up to f _vSeparate;

2.3) the current AP of sign is allocated channel AP, renewal AP allocated channel state information;

3) estimate the signal interference ratio of each AP, and with its threshold ratio, have the situation of signal interference ratio greater than threshold value, consider authorizing the frequency allocation channel, its process is following:

3.1) according to the power spectral density calculating channel isolation of signal on the ISM band channel, said channel isolation computational methods are following:

$\mathrm{\&phi;}(c_i,c_j)={\&Integral;}_{-\&infin;}^{+\&infin;}{S}_t\left(f\right)S_r(f-\mathrm{\&tau;})\mathrm{df}---\left(3\right)$

Wherein, c _iBe to distribute to AP _iChannel, c _jBe to distribute to AP _jChannel, S _t(f) expression AP transmission power distribution, S _r(f) expression AP received power distributes, and τ is AP _iAnd AP _jOffset frequency between the channel overlap;

3.2) combining channel isolation and overlapping region, the computational methods of signal interference ratio are following:

${\mathrm{SIR}}_i=\frac{{\mathrm{\&pi;<figure-callout\; id="1"\; label="r"\; filenames="HSA00000751197700012.png"\; state="\{\{state\}\}">r</figure-callout>}}_1^2}{\underset{j=1,j\&NotEqual;i}{\overset{N}{\mathrm{\&Sigma;}}}\mathrm{\&phi;}(c_i,c_j)A_{\mathrm{ij}}}---\left(4\right)$

With the signal interference ratio of each AP and its threshold ratio, authorize frequency range whether to have available channel if exist signal interference ratio then to investigate greater than the situation of threshold value;

3.3) authorize the frequency range channel-aware, its process is following:

$\underset{\{r_j,x_j\}}{\max }\underset{j=\mathrm{0,1}}{\mathrm{\&Sigma;}}{\mathrm{\&pi;}}_j{r}_j\mathrm{Pr}\{r_j\&le;{\log }_2[1+\frac{x_j{g}_{\mathrm{ss}}}{(1-z_j){\mathrm{Yg}}_{\mathrm{ps}}+n}\left]\right\}$

$s.t.\underset{j=\mathrm{0,1}}{\mathrm{\&Sigma;}}{\mathrm{\&pi;}}_j{x}_j\&le;{\mathrm{\&Gamma;}}_1---\left(5\right)$

$\underset{j=\mathrm{0,1}}{\mathrm{\&Sigma;}}{\mathrm{\&pi;}}_j{\mathrm{\&alpha;}}_{0j}{x}_j{g}_{\mathrm{sp}}\&le;{\mathrm{\&Gamma;}}_2$

Wherein, π ₀The expression sensing results is for authorizing the probability of frequency range channel busy, π ₁The probability of expression sensing results for authorizing the frequency range channel to use, r ₁, x ₁The state of secondary user when the frequency range channel idle is authorized in expression, g _SsBe the channel power gain of secondary user's transmitted from transmitter to receiver, g _PsBe of the gain of main user transmitter to secondary user's receiver, g _SpBe the gain of secondary user's transmitter to main receiver user, z _jFrequency range channel busy, z are authorized in=0 expression _j=1 expression authorizes the frequency range channel can use α _IjIt is i and sensing results is the posterior probability of j that the frequency range virtual condition is authorized in expression back;

3.4) authorize the frequency range channel can use then assigns authorized frequency range channel, otherwise press ISM band channel allocation allocated channel as a result.

Claims (3)

1. one kind is mixed band A P method for channel allocation, and it is characterized in that: said method for channel allocation may further comprise the steps:

1) AP weighing computation method, the priority of AP channel allocation are pressed the big or small descending of AP weight, and its process is following:

1.1) according to adjacent AP _iCommunication radius r ₁And AP _jThe interference radius r ₂, calculate AP _iCommunication zone and AP _jThe overlapping area of interference region, said area computation method is following:

$A_{\mathrm{ij}}=\left\{\begin{array}{cc}\frac{1}{2}{r}_1^2[{\mathrm{\&theta;}}_1-\sin \left({\mathrm{\&theta;}}_1\right)]+\frac{1}{2}{r}_2^2[{\mathrm{\&theta;}}_2-\sin \left({\mathrm{\&theta;}}_2\right)],& d_{\mathrm{ij}}<r_1+r_2\\ 0,& d_{\mathrm{ij}}\&GreaterEqual;r_1+r_2\end{array}\right.---\left(1\right)$

Wherein, d _IjBe AP _iWith AP _jBetween distance, θ ₁Be AP _iThe central angle of lap, θ ₂Be AP _jThe central angle of lap;

1.2) calculate each AP and other AP overlapping area sum, it is compared with the area of communicating by letter, obtain the AP weight, said computational methods are following:

$W_i=\frac{\underset{j=1,j\&NotEqual;i}{\overset{N}{\mathrm{\&Sigma;}}}{A}_{\mathrm{ij}}}{{\mathrm{\&pi;r}}_1^2}---\left(2\right)$

Wherein, N is the AP number;

1.3) weight selection the maximum among the AP of allocated channel never, be its distribution preferred channels by the integral linear programming method;

2) calculate signal interference ratio; If all AP signal interference ratios are all then preserved allocation result less than its threshold value, if there be the situation of AP signal interference ratio greater than its threshold value, investigation authorizes frequency range whether to have available channel; If existing then is its assigns authorized frequency range channel, then do not keep former channel allocation result if do not exist.

2. mixing band A P method for channel allocation according to claim 1, it is characterized in that: said step 2), the AP positional information is definite, and the power that AP receives client is definite value; Client is obeyed Poisson distribution in the AP communication zone, equiprobability inserts interfering AP in the interference region; Client-side information priority equiprobability and appearance at random, same priority information equiprobability access communications network.

3. mixing band A P method for channel allocation as claimed in claim 1 is characterized in that: said step 2), distribute preferred channels by the weight descending for corresponding A P, choose the channel with adjacent AP quadrature; For all AP calculate the signal interference ratio of each AP after the ISM band allocated channel, and compare in its communication threshold value; If there be the situation of signal interference ratio greater than threshold value, use maximum detection probability or minimum false alarm probability perception mandate frequency range whether to have available channel, then insert if exist, otherwise distribute by the ISM band allocation result with the cognitive radio mode.

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