CN104581813A - Dynamic channel allocation method of WLAN (wireless local area network) system - Google Patents

Abstract

The invention discloses a dynamic channel allocation method of a WLAN (wireless local area network) system. AP (access point) nodes of the WLAN system measure signal strength, generate signal strength test reports and transmit the signal strength test reports to a wireless AC (access controller); the wireless AC builds a system interference model and sets interference model parameters through the signal strength; calculating is performed by optimization to obtain a group of channel numbers allowing a smallest interference model; the wireless AC allocates a running frequency point for each AP node according to the calculated channel numbers and distributes the running frequency points to the AP nodes through configuration files; the AP nodes adjust running frequencies according to the configuration files. The dynamic channel allocation method helps reduce intra-system interference and improve system capacity.

Description

A kind of wlan system dynamic channel assignment method

Technical field

The present invention relates to the frequency planning technology in the WLAN communications field, particularly relate to the operating frequency system of selection of AP node in the wlan system based on 802.11 agreements.

Background technology

The appearance of WLAN (wireless local area network), as a kind of widely used access technology, provides broadband wireless access to arrive Internet.Wlan system based on 802.11 be wireless terminal anywhere or anytime broadband access Internet provide possibility, in campus, the field such as hotel and office building is widely applied.Wlan system comprises AC (wireless controller), AP (WAP (wireless access point)) and STA (website and terminal equipment).

In order to ensure that the terminal in local area network provides high-peed connection anywhere or anytime, the construction of WLAN needs to arrange a large amount of AP node usually, in order to ensure that AP node obtains maximum throughput, must reduce the interference between AP, rational frequency planning is one of key technology becoming WLAN construction.In actual application, be subject to the impact of the many factors such as heterogeneity that position, user distribution are provided of power supply, be difficult to the covering realizing whole wireless network according to a certain harmonized programme, therefore this irregular AP laid, need a kind of effective frequency planning means.

Summary of the invention

For solving the deficiency that prior art exists, the invention discloses a kind of wlan system dynamic channel assignment method, the planning problem of this patent pin AP node working frequency points, applies for the frequency planning based on channel disturbance model.Main thought is the interference model setting up wlan system, target setting function for the purpose of interference model value is minimum, by the frequency parameter adopting optimal method to ask one group of AP node.

For achieving the above object, concrete scheme of the present invention is as follows:

A kind of wlan system dynamic channel assignment method, comprises the following steps:

Step one: AP node settling signal ionization meter in wlan system, and generate signal strength test report, test report is sent to AC wireless controller;

Step 2: AC wireless controller sets up system interference model, and adopt signal strength signal intensity that interference model parameter is set, adopt optimal method to calculate the one group of channel number making interference model minimum;

Step 3: AC wireless controller is each AP Joint Enterprise working frequency points according to the channel number calculated, and working frequency points is handed down to each AP node by configuration file; AP node adjusts operating frequency according to configuration file.

The detailed process of described step one is: initial time, all AP Joint Enterprise are same channel by AC wireless controller, working frequency points by all AP nodes is set to setpoint frequency, transmitted power is set to p, and indicate and need periodic measurement signal strength signal intensity, generating configuration file is also issued to all n AP node and (supposes to be respectively AP ₁, AP ₂..., AP _n), AP node carries out work according to configuration file given parameters, start timer, when timer expires, the all channels of AP node scan, detect the relevant information of the signal strength signal intensity that each channel receives and the AP node producing this signal, generate signal strength signal intensity report, send to AC wireless controller.

In described step 2, system interference model definition is:

$\mathrm{\δ}(f_1,f_2\·\·\·f_n)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\δ}}_{\mathrm{ij}}$

Wherein δ (f ₁, f ₂f _n) always disturb for system, f ₁, f ₂f _nfor the channel number of the n in wlan network AP node, δ _ijfor AP _inamely i-th AP node is to AP _jan i.e. jth AP node) interference value.

δ _ijit is defined as the relevant function of the working channel of signal power and the AP received:

${\mathrm{\δ}}_{\mathrm{ij}}=\left\{\begin{array}{cc}{P}_{\mathrm{ij}}\exp [-{(f_i-f_j)}^2]& i\≠j\\ 0& i=j\end{array}\right.$

Wherein: P _ijfor AP _ireceive from AP _jsignal strength signal intensity, f _iand f _jfor AP _iand AP _jthe channel number used.

Described wlan system comprise 1 AC and n AP, n be more than or equal to 1 integer.

Described AP node carries out signal strength measurement and can be undertaken by AC wireless controller transmission message trigger.

Operation principle: during initialization, AC arranges all AP and is operated in same channel f _i, and the standard of employing transmitted power p, configuration file is handed down to all AP by AC.

AP according to the configuration file work received, and periodically detects the signal strength signal intensity from other AP, generates signal strength signal intensity report, and signal strength signal intensity report is sent to AC.

AC with the signal strength signal intensity obtained for parameters P _ij, set up system interference model.

Optimization algorithm is adopted to ask for the one group of parameter (f making system interference minimum ₁, f ₂f _n);

By (f ₁, f ₂f _n) as the channel number of n AP node, the operating frequency of this node is set according to the numbering of each AP node, generating configuration file, and is handed down to each AP node.

AP node receives and adjusts operating frequency according to configuration file.

Beneficial effect of the present invention:

The planning problem of this patent pin AP node working frequency points, proposes a kind of frequency planning method based on channel disturbance model.Implementing of the method helps reduce intrasystem interference, improve power system capacity.

Accompanying drawing explanation

Fig. 1 wlan system schematic diagram;

Fig. 2 AC channel allocation workflow;

Fig. 3 AP channel allocation workflow.

Embodiment:

Below in conjunction with accompanying drawing, the present invention is described in detail: as shown in Figure 1,1 AC and n AP is comprised in a wlan system, initial time, all AP are configured to 1 channel by AC, and the working frequency points of all AP is set to 2.412GHz, transmitted power is set to 500mW, and indicates and need periodic measurement signal strength signal intensity, and generating configuration file is also issued to all n AP.AP node carries out work according to configuration file given parameters, start timer, when timer expires, the all channels of AP node scan (2.4GHz frequency range China is No. 1-13), detect signal strength signal intensity and transmitting terminal AP that each channel receives, generation signal strength signal intensity is reported, sends to AC.The report of the signal strength signal intensity from n AP that AC node receives, obtains P according to signal strength signal intensity report _ij, i.e. AP _ireceive from AP _jsignal strength signal intensity, set up system interference model $\mathrm{\δ}(f_1,f_2\·\·\·f_n)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\δ}}_{\mathrm{ij}}$

Wherein, δ (f ₁, f ₂f _n) always disturb for system, f ₁, f ₂f _nfor the channel number of the n in wlan network AP node, δ _ijfor AP _i(i-th AP node) is to AP _jthe interference value of (a jth AP node).

δ _ijit is defined as the relevant function of the channel of signal power and the AP received:

${\mathrm{\δ}}_{\mathrm{ij}}=\left\{\begin{array}{cc}{P}_{\mathrm{ij}}\exp [-{(f_i-f_j)}^2]& i\≠j\\ 0& i=j\end{array}\right.$

Wherein: P _ijfor AP _ireceive from AP _jsignal strength signal intensity, f _iand f _jfor AP _iand AP _jthe channel number used.

Optimization algorithm is adopted to ask for the one group of parameter (f making system interference minimum ₁, f ₂f _n);

By (f ₁, f ₂f _n) as the channel number of n AP node, the operating frequency of this node is set according to the numbering of each AP node, generating configuration file, and is handed down to each AP node.

AP node receives configuration file and adjusts operating frequency according to configuration file.

The workflow of AC as shown in Figure 2, the working channel arranging n AP is k, issue configuration file, receive and report from the signal strength signal intensity of AP, interference model optimum configurations, adopt optimal method to ask for channel parameter group, judge whether channel parameter upgrades, if so, then each AP working frequency points is set, issues configuration file.

The workflow of AP as shown in Figure 3, starts, judge timer whether time-out and AC whether require to carry out signal strength test, if so, scanning channel, generates signal strength signal intensity report, reports to AC strength of transmitted signals.AC is generally by wired connection AP node, and AP node is by wireless connections terminal equipment, and terminal equipment is mobile phone, notebook and so on.

By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendment or distortion that creative work can make still within protection scope of the present invention.

Claims (6)

1. a wlan system dynamic channel assignment method, is characterized in that, comprises the following steps:

Step one: AP node settling signal ionization meter in wlan system, and generate signal strength test report, test report is sent to AC wireless controller;

Step 2: AC wireless controller sets up system interference model, and adopt signal strength signal intensity that interference model parameter is set, adopt optimal method to calculate the one group of channel number making interference model minimum;

Step 3: AC wireless controller is the configuration effort frequency of each AP node according to the channel number calculated, and working frequency points is handed down to each AP node by configuration file; AP node adjusts operating frequency according to configuration file.

2. a kind of wlan system dynamic channel assignment method as claimed in claim 1, it is characterized in that, the detailed process of described step one is: initial time, all AP Joint Enterprise are same channel by AC wireless controller, working frequency points by all AP nodes is set to setpoint frequency, transmitted power is set to p, and indicate and need periodic measurement signal strength signal intensity, generating configuration file is also issued to all n AP, AP node carries out work according to configuration file given parameters, start timer, when timer expires, the all channels of AP node scan, detect the relevant information of the signal strength signal intensity that each channel receives and the AP node producing this signal, generation signal strength signal intensity is reported, send to AC wireless controller.

3. a kind of wlan system dynamic channel assignment method as claimed in claim 1, is characterized in that, in described step 2, system interference model definition is:

$\mathrm{\δ}(f_1,f_2...f_n)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\δ}}_{\mathrm{ij}}$

Wherein δ (f ₁, f ₂f _n) always disturb for system, f ₁, f ₂f _nfor the channel number of the n in wlan network AP node, δ _ijfor AP _inamely i-th AP node is to AP _jthe i.e. interference value of a jth AP node.

4. a kind of wlan system dynamic channel assignment method as claimed in claim 3, is characterized in that, δ _ijit is defined as the relevant function of the channel of signal power and the AP received:

${\mathrm{\δ}}_{\mathrm{ij}}=\left\{\begin{array}{cc}{P}_{\mathrm{ij}}\exp [-{(f_i-f_j)}^2]& i\≠j\\ 0& i=j\end{array}\right.$

Wherein: P _ijfor AP _ireceive from AP _jsignal strength signal intensity, f _iand f _jfor AP _iand AP _jthe channel number used.

5. a kind of wlan system dynamic channel assignment method as claimed in claim 1, is characterized in that, described wlan system comprise 1 AC and n AP, n be more than or equal to 1 integer.

6. a kind of wlan system dynamic channel assignment method as claimed in claim 1, is characterized in that, described AP node carries out signal strength measurement and can be undertaken by AC wireless controller transmission message trigger.