CN100454874C - System and method for preventing radio local network self-interference - Google Patents

Abstract

A system for preventing WLAN from self-interference comprises access point AP, multiple station STA controlled by said AP, centralized control platform AC connected to AP and used to detect/obtain quality of communication channel used currently by AP as well as used to issue management command to AP to let AP regulate currently used communication channel.

Description

A kind of system and method that prevents the WLAN (wireless local area network) self-interference

Technical field

The present invention relates to the technology that avoids interference at wireless lan (wlan), particularly a kind of system and method that prevents the WLAN self-interference.

Background technology

WLAN and wireless personal network (WPAN) enter China the end of the nineties, obtained developing in short time more than ten years swift and violently, wherein with the WLAN of IEEE802.11b standard, have occupied most market shares.

Along with popularizing of the 802.11b/g of Institute of Electrical and Electronics Engineers (IEEE), the shortcoming of WLAN self also comes out very soon.IEEE802.11b/g is operated in the common frequency band of 2.4Ghz, in the bandwidth of 83.5M, though there are 13 channels, but non-interfering channel only can coexist 3 simultaneously, during the hot zones of some in WLAN large scale deployment WAP (wireless access point) (AP), certainly exists the problem of channel resource conflict and phase mutual interference like this, along with the traffic carrying capacity of WLAN increases, it is intensive more that AP disposes, and the phase mutual interference of interchannel is serious more, even make the WLAN can't operate as normal.

Research at WLAN at present has a lot of aspects, comprises (DCF) performance evaluation of multiple step format coordination function and improvement and optimization and supports the solution that different business flows, i.e. service quality problem research on the WLAN etc. at WLAN.Wherein to the self-interference research of WLAN seldom, research mainly concentrates in the external interference of WLAN, and the relevant patent of proposition has that for example the dynamic frequency selection scheme of IEEE802.11 WLAN (wireless local area network) and the dynamic frequency of WLAN (wireless local area network) are selected and detections of radar.Below these two patents are illustrated respectively.

Scheme one

At number of patent application is 02801617.3, name is called in the patent application of " the dynamic frequency selection scheme of IEEE802.11 WLAN (wireless local area network) ", when two Basic Service Sets that close on (BSS) each other the position near and when on identical channel, moving, be referred to as the BSS that overlaps, then be difficult to the service quality (QoS) of data that support is transmitted because of possible phase mutual interference between the overlapping BSS.In addition, other colocated systems of closing on BSS can cause receiving interference, even planned carefully that the channel allocation of BSS also can not avoid interference before disposing WLAN, particularly in family or office environment, other wlan devices just nearby.Therefore, this patent application has proposed the method and system of Dynamic Selection communication channel, and this system can merge in the IEEE802.11 standard, makes access point (AP) be station (STA) the Dynamic Selection communication channel relevant with its BSS.This patent application is introduced parameter in 802.11MAC and PHY standard, feasible operation for WLAN can the Dynamic Selection communication channel.

Fig. 1 is the operational flowchart that selectively exchanges to new communication channels of prior art scheme one, if one of following incident, then AP dynamically selects new communication channel to move BSS when AP monitors the communication channel of the BSS that administers.

1, forms new BSS by described AP; 2, described AP or described STA have experienced bad communication channel situation; 3, described BSS with close on BSS and overlap; 4, surpass predetermined period of time and do not have the association of appearance by the described STA of described AP; 5, in described BSS, detect another licensed operator.

Before being transformed into new communication channel, AP need be by direct detection communication channel situation or by learning the state of current other communication channels and other licensed operators' existence from relevant STA request channel situation.In this monitoring process, the process of AP measured channel can be by the channel measurement of AP, and the measurement report of AP request channel measurement or a plurality of STA obtains the quality report of communication channel.

Fig. 2 is the implementation method flow chart of prior art scheme one, and the step of this implementation method comprises: determining whether need be by the new communication channels of a plurality of wireless STA uses; Measure the channel quality of a plurality of communication channels by among a plurality of STA that administered at least one; STA reports the channel quality of a plurality of communication channels according to the signal strength signal intensity indication (RSSI) that receives, busy cycle of clear channel assessment (CCA) and periodicity; AP selects the communication channel of one of candidate communication channel to be used for communication between AP and a plurality of STA based on channel quality reporting.The concrete steps of this scheme are:

Step 200～201, AP select communication channel and determine whether each STA that is administered has detected the existence of another BSS in the signal of its acceptance from institute's candidate communication channel, if, execution in step 202; Otherwise, execution in step 203.

Step 202, AP determine whether be set from digital service (DS) territory (perhaps from AP), if, execution in step 204; Otherwise, execution in step 205.

Be used to determine from DS territory (perhaps from AP) and during measuring, receive the frame that has at least from the DS territory respectively.

Step 203, AP determine whether to detect the periodicity of received signal, if, execution in step 206; Otherwise, execution in step 205.

Step 204, AP get rid of corresponding communication channel from the candidate communication channel list, change step 207 over to.

Step 205, AP are included in the communication channel of correspondence in the candidate communication channel list, change step 207 over to.

Step 206, AP get rid of corresponding communication channel from the candidate communication channel list, change step 207 over to.

Step 207, AP determine whether institute's candidate communication channel all has been scanned, if change step 208 over to; Otherwise, change step 200 over to.

Step 208, AP select to have minimum RSSRI or/and the communication channel of CCA value, promptly after obtaining a plurality of potential candidate channel, AP determines that not only other STA of BSS are had least interference, and to have the specific communication channel of least interference as other colocated systems of HIPERLAN/2 equipment, last AP determines the communication channel that the communication channel of selection must be transformed into as all STA.

But adopt such scheme to exist shortcoming: 1, this scheme is primarily aimed at the interference from non-wlan device, therefore for the interference from WLAN self, as comprises not research such as interference strength; 2, this scheme need change mac-layer protocol and the physical layer protocol of IEEE 802.11, therefore can not utilize the existing equipment among the WLAN; 3, this scheme adopts physical layer primitive and new mac layer frame structure to obtain the method complexity for the measurement of channel quality; 4, adopt in this scheme hardware device and software module be embedded in and change current frequency of utilization among the AP, the method complexity; 5, this scheme does not provide the beneficial effect that adopts the dynamic frequency selection algorithm.

Scheme two

At number of patent application is 03805034.x, name is called in the patent application of " dynamic frequency of WLAN (wireless local area network) is selected and detections of radar ", when the radar equipment that is operated in the 5GHz frequency range and WLAN were operated in same frequency and the coverage the other side, both can interfere with each other.In order to guarantee both sides' operate as normal, WLAN should be able to start or the course of work in the testing channel frequency, occurring under the situation about disturbing, WLAN automatically switches to optimum available communication channel.

Fig. 3 is the communication system block diagram of prior art scheme two, as shown in the figure: this communication system WLAN or other wireless networks that to be one or more wireless communication link form with one or more communication equipment and communication base station, the radar signal of radar source emission may interference base station with equipment and other networks between the Radio Link of communicating by letter; Otherwise the signal of communication of base station also may disturb the signal of radar.

Fig. 4 is the schematic diagram of prior art scheme two detections of radar receiver systems, as shown in the figure: radar receiver is by antenna receiving radar signal, and radar signal and the reconcilable reference signal of radar receiver self, compare as-52dBm, when the power level of radar signal is equal to or greater than reference signal, show that radar receiver detects the radar signal that may produce interference.

The radar signal pulse that radar receiver receives is through shaping, the wireless network signal pulse that receives with communication control processor is carried out and (AND) decision of door, communication control processor scans all working channel frequency of current communication system, when the communication channel of Radar channel and communication control processor is a same communication channel or when interfering with each other at least, the output of AND door must be high level, radar chaff this moment communication channel is exactly the current scan communication channels of communication control processor, judges by this method to produce the radar communication channel that disturbs.

In the drawings, the available communication channel of current optimum is selected by RSSI or SNR are measured in the RSSI/SNR unit.

Fig. 5 is the embodiment flow chart of prior art scheme two, and its concrete steps are:

Step 500, radar receiver receive radar signal.

Step 501～502, radar receiver are judged radar signal and the reference signal that receives, and judge whether the power of radar signal is equal to or greater than the preset threshold level, if, execution in step 503; Otherwise, execution in step 500.

When step 503～504, communication control processor scanning radio network information channel mate the communication channel of Radar channel up to its communication channel that receives signal, be judged to be the signal of radar communication channel.

Step 505～506, judge the quality of one or more radio network information channels by the RSSI/SNR unit, tuning communication control processor is to higher-quality communication channel.

Such scheme also exists shortcoming: 1, this scheme is only at the mutual interference mutually between WLAN communication system and the radar equipment, and do not study the co-channel interference between the Basic Service Set (BSS) of WLAN communication system self; 2, this scheme requires to adopt the special hardware equipment that can detect radar signal and wireless network signal, and is with high costs; 3, this scheme judge radar signal interference based on predetermined threshold value, and can not according to circumstances dynamically adapt to concrete environment so that WLAN reaches higher communication quality; 4, this scheme does not illustrate detailed solution to the judgement of quality of wireless channel, and channel quality is not defined concrete indication standard.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of system of the WLAN of preventing self-interference, and this system can indicate self interference strength of WLAN, and carries out the dynamic frequency adjustment of channel according to self interference strength.

The present invention also provides a kind of method of the WLAN of preventing self-interference, and this method can be indicated self interference strength of WLAN, and carries out the dynamic frequency adjustment of channel according to self interference strength.

According to above-mentioned purpose, technical scheme of the present invention is achieved in that

A kind of system that prevents WLAN (wireless local area network) WLAN self-interference, this system comprises a plurality of site STA of access point AP and its administration, this system comprises that also centralized control platform AC is connected with AP, be used for detecting and obtain the presently used communication channel quality of AP, by the administration order of Simple Network Management Protocol transmission to AP, make AP adjust presently used communication channel, described AC detects and obtains the presently used communication channel quality of AP is by sending packet for one of them STA that AP administered, writing down the number of data packets that sends, the time delay of packet and the number of dropped packets of packet calculate.

A kind of method that prevents the WLAN self-interference is provided with AC in WLAN, this method also comprises:

A, AC send packet to one of them STA that AP administered, send the time delay of number of data packets, packet and the number of dropped packets of packet according to obtaining and calculate the current channel quality value of using communication channel of AP, determine whether this channel value that calculates reaches the definite value of the communication channel of adjusting the current use of AP, if, execution in step B; Otherwise, return steps A and continue to carry out;

B, AC send to AP current communication channel are adjusted to the current administration order of using the adjacent communication channel of communication channel of AP, and AP adjusts to the current adjacent communication channel that uses communication channel of AP with current communication channel after receiving this administration order.

Before steps A, this method also comprises:

AC obtains the STA address list of its administration and decides the interval by AP, from the STA address list behind STA of picked at random, and execution in step A.

The described packet of steps A sends surely at interval at setting cycle, and this setting transmission cycle is that AC gets access to by AP,

Steps A is described to obtain the time delay of the number of data packets that sends, packet and the number of dropped packets of packet is the mean value of setting in the transmission cycle.

The described packet of steps A is the Ping bag.

Before the described definite value that determines whether to reach the communication channel of adjusting the current use of AP of steps A, this method also comprises:

AC determines whether to reach the enabling gate limit value and starts the STA number according to the startup thresholding that gets access to from AP, if then the subsequent step of A is carried out in continuation; Otherwise, return steps A.

The described AP of calculating of steps A is current, and to use the channel quality value of communication channel be basis $Q\left(f\right)=p/N+\frac{1-p}{N}(t-t_0)/(T-t_0)$ Obtain:

As Q (f) when being not more than 1, do not adjust the presently used communication channel of AP;

Wherein, f represents that the employed frequency of AP, N represent that AC sends out the sum of packet, and p represents AC packet discard sum, t ₀Receive the average delay of packet during expression communication channel idle condition, t represents that AC receives the average delay of packet, and T is the threshold value that sets, and Q (f) is the channel quality value of the communication channel of the current use of AP.

Before step B, this method also comprises:

AC measures the current channel quality that uses the adjacent communication channel of communication channel of AP, judges that whether the channel quality value obtain deducts AC by the confidence level that AP obtained less than 1, if, execution in step B then; Otherwise, change steps A over to and continue to carry out.

Described AC measures the current channel quality process of the adjacent communication channel of communication channel of using of AP:

AC sends the time delay of number of data packets, packet and the number of dropped packets of packet and adopts to adopting the current STA of the adjacent communication channel of communication channel that uses of AP to send packet according to obtaining $Q\left(f\right)=p/N+\frac{1-p}{N}(t-t_0)/(T-t_0)$ Obtain channel quality value;

Wherein, f represents that the employed frequency of AP, N represent that AC sends out the sum of packet, and p represents AC packet discard sum, t ₀Receive the average delay of packet during expression communication channel idle condition, t represents that AC receives the average delay of packet, and T is the threshold value that sets, Q (f) by AP current the channel quality of adjacent communication channel of use communication channel.

From such scheme as can be seen, the present invention solves adjacent problem of co-channel interference with AP generation frequently preferably, detect by continuing sufficient communication channel, can make with the heavier AP of load among the frequency AP selects the lighter communication channel of adjacent load to carry out redirect, by alleviating the load capacity of same communication channel, reduce with the interference of AP frequently, improve the throughput of system of WLAN.Therefore, method provided by the invention can be indicated self interference strength of WLAN, and carries out the dynamic frequency adjustment of channel according to self interference strength.

Description of drawings

Fig. 1 is the operational flowchart that selectively exchanges to new channel of prior art scheme one;

Fig. 2 is the implementation method flow chart of prior art scheme one;

Fig. 3 is the communication system block diagram of prior art scheme two;

Fig. 4 is the schematic diagram of prior art scheme two detections of radar receiver systems;

Fig. 5 is the embodiment flow chart of prior art scheme two;

Fig. 6 is the schematic network structure of BSS of the present invention;

Fig. 7 is overlapped schematic network structure between the BSS of the present invention;

Fig. 8 prevents the system of WLAN self-interference for the present invention;

Fig. 9 prevents the method flow diagram of WLAN self-interference for the present invention.

Embodiment

In order to make the purpose, technical solutions and advantages of the present invention clearer, below lift specific embodiment and, the present invention is described in more detail with reference to accompanying drawing.

According to IEEE 802.11 agreements, each AP has certain coverage, and the STA in coverage is connected with AP, has constituted a BSS, as shown in Figure 6.Because the relation of physical location, the coverage of the BSS that closes on is easily overlapped, again because can only have 3 non-interfering communication channels at most in the same physical region, so, be prone to AP and be in the situation of same communication channel, be referred to as adjacent with AP frequently, as shown in Figure 7.

If adjacent load with frequency AP is bigger, the same frequency communication channel that then produces is disturbed also relatively more serious, so the quality of communication channel is also poor.Therefore, the present invention is mainly used to solve adjacent with the interference problem between the frequency AP, by the dynamic frequency selection algorithm, reduces adjacent interference between the AP frequently together, thereby improves the throughput of whole WLAN.Specific implementation process of the present invention is:

The first step: in WLAN, be provided with one and be used for the centralized control platform (AC) that the AP frequency is adjusted;

Second step: the channel quality formula that an expression communication channel is set;

The 3rd step: the Internet Control Message Protocol (ICMP) of using Internet protocol (IP) layer, measure the situation that the AP compass of competency STA of institute receives packet by the AC that is provided with according to certain rule, and calculate the channel quality value of the presently used communication channel of AP according to the formula in second step;

The 4th step: the channel quality value by the communication channel value that calculates determines whether to adjust the presently used communication channel of AP, if dynamically indicate AP to adjust the presently used communication channel of AP by AC.

In the present invention, the first step and second step do not have sequencing.

Below specify system and method provided by the invention.

Fig. 8 prevents the system of WLAN self-interference for the present invention, and this system forms by having AC, the AP and the STA that detect communication channel quality and adjust the communication channel of AP.Wherein, AP administers a plurality of STA.AC links to each other with AP by wired network, detects the communication channel quality that obtains the current place of AP by ICMP, by the administration order of Simple Network Management Protocol (SNMP) issue to AP.

AC issue is the communication channel quality decision at the current place of AP that obtains according to detection to the administration order of AP: when the communication channel that detects the current place of AP takes place to disturb, then send the administration order of adjusting the current place of AP communication channel; When the communication channel that detects the current place of AP is disturbed, then do not send the administration order of adjusting the current place of AP communication channel.

In the present invention, AC adopts according to the time interval of setting and sends out the method for fixed-length data bag to the STA that inserts AP, and the current communication channel that obtains each AP institute compass of competency receives the situation of packet, and its concrete grammar is:

At first, AC reads the STA address list that connects each AP among the WLAN every one-period T by SNMP.Obtain longer relatively that the period T of STA address list is provided with, this is that the AP that strides that generally can be not frequent moves because STA is relatively stable in a zone that AP administered.

Secondly, AC selects a STA at random from the STA address list of each AP, the Ping that uses ICMP to issue fixed length wraps the STA of selected each AP, sets to carry out repeatedly at interval surely, record sends the time delay and the number of dropped packets of Ping bag.

Certainly, in the present invention, the packet that AC sent is not limited only to the Ping bag, can also be other packets.

At last, AC obtains Ping bag transmission number in this way, Ping wraps time delay and the Ping bag packet loss number that sends, and detects the situation of the reception packet of the communication channel of each AP institute current use in compass of competency among the WLAN constantly.

Channel quality value for the communication channel that characterizes the current use in compass of competency of AP institute, can adopt formula 1:

$Q\left(f\right)=p/N+\frac{1-p}{N}(t-t_0)/(T-t_0)---\left(1\right)$

Formula (1) characterizes the idle-mode value of communication channel, and judges the co-channel interference size of this communication channel as foundation with this.Wherein, f represents that the employed frequency of AP, N represent that AC sends out the sum of Ping bag in measuring period, and p represents the packet loss sum of AC in measuring period, t ₀Receive the average delay (generally can ignore) of Ping bag during expression communication channel idle condition, t represents that AC receives the average delay of Ping bag in measuring period, T is the threshold value that sets, generally determine that according to the current loading condition of WLAN Q (f) is the channel quality value of the communication channel of the current use of AP.When Q (f)=1, be a critical value, the backward breakover point of expression channel quality carries out AC according to this value AP is sent administration order, and AP adjusts presently used communication channel.

In the present invention, receive the situation of packet, adopt the dynamic frequency selection algorithm to determine whether to make AP to adjust the communication channel of current use based on formula (1) and the current communication channel that obtains each AP institute compass of competency.

In the present invention, following hypothesis is provided with the dynamic frequency selection algorithm based on being based on:

1, it is overlapping that the high density WLAN environment that has a plurality of AP and STA, adjacent AP compass of competency cover, and each AP has its adjacent AP set, has comprised the adjacent AP of all and its overlapping covering; 2, AC determines whether to start the dynamic frequency algorithm according to the channel quality value that measurement calculates the current use communication channel of AP; 3, which communication channel is the relation of the channel quality value of the communication channel used of the channel quality value of the communication channel adjacent with current use communication channel that calculate according to measurement of each AP and current AP determine to adjust to; 4, exist the communication channel of non-overlapped covering using among the WLAN, i.e. WLAN load is unbalanced.

Fig. 9 prevents the method flow diagram of WLAN self-interference for the present invention, and this method adopts the dynamic frequency selection algorithm of setting of the present invention to carry out, and its concrete steps are:

Step 900, behind the AP of WLAN starting up, AP carries out parameter initialization, AC can get access to the parameter of AP, and these parameters comprise: AC obtains period T, communication channel measuring intervals of TIME and long data packet, packet loss thresholding, the enabling gate limit value of the address list that inserts AP and starts STA number, confidence level M and communication channel and confirms to measure times N.

Step 901, AC carry out the detection of reception packet situation of the communication channel of the current use of AP, first cycle detection to value directly leave in the communication channel state table of the current use of AP of setting, the measured value that measures of the value of each period measurement and last one-period averages afterwards, upgrades the communication channel state table of the current use of AP.

In the present invention, the time delay of the value that measures for sending number of data packets, losing number of data packets and transmission packet.

Step 902, AC according to the transmission number of data packets that in the communication channel state table of the current use of AP, writes down, send the packet time delay and lose number of data packets, judge whether to reach the thresholding of startup, if change step 903 over to; Otherwise, change step 901 over to.

Step 903, AC according to the transmission number of data packets that in the communication channel state table of the current use of AP, writes down, send the packet time delay and lose number of data packets, judge whether to reach and start the STA number, be to change step 904 over to; Otherwise, change step 901 over to.

When carrying out, the execution sequence of step 902 and step 903 can exchange.

Step 904, AC measure and record the communication channel of the current use of the AP communication channel adjacent with it respectively, confirm, the channel quality value that obtains the current communication channel of using of AP is q1; The channel quality value of the communication channel that it is adjacent is q2.

Whether step 905, AC judge q1 greater than 1, if, execution in step 906; Otherwise, change step 901 over to.

Whether step 906, AC judge q2 less than 1-M, if, execution in step 907; Otherwise, change step 901 over to.

Step 907, AC send to AP and adjust on the good communication channel of known channel quality, return step 901 and continue to carry out, and the measured communication channel of this known channel matter is the adjacent communication channel of communication channel of the current use of AP.

In the present invention, the value of each parameter of AP is as shown in table 1.

Parameter name	Optional scope	Default value
			Period T	3-5 minute	3 minutes
The communication channel measuring intervals of TIME	0.5-2 second	1 second
			Data packet length	The 32-64 byte	32 bytes
The packet loss thresholding	0.5-2 second	1 second
			The enabling gate limit value	The 50-80 millisecond	65 milliseconds
Start the STA number	5-8	5
			Confidence level M	0.4-0.6	0.5
Communication channel confirms to measure number of times	30-100 time	60 times

Table 1

Wherein, confidence level M represents the interval between the communication channel of communication channel that channel quality that WLAN confirms is good and bad channel quality, this confidence level M can adopt prior art to calculate or be provided with and obtain, concussion for fear of communication channel is switched, calculate the channel quality q2 of the communication channel preferably of adjacent communication channel according to formula (1), use formula (2) to judge then.

q2＜1-M (2)

The main applied scene of system and method provided by the invention is: the hot zones among the unbalanced or WLAN of the whole system load Distribution of WLAN, make the local throughput of system of WLAN reach capacity, wherein, hot zones has two features: STA quantity is many and traffic carrying capacity is big, and is at full capacity local.

The present invention can solve adjacent problem of co-channel interference with AP generation frequently preferably, detect by continuing sufficient communication channel, can make with the heavier AP of load among the frequency AP selects the lighter communication channel of adjacent load to carry out redirect, by alleviating the load capacity of same communication channel, reduce with the interference of AP frequently, improve the throughput of system of WLAN.Through theoretical research demonstration and experiment simulation, the throughput of system that on average can improve WLAN reaches 10%～30%, and remarkable more under the unbalanced situation of WLAN, and the effect of dynamic frequency selection algorithm provided by the invention is also good more.

System and method provided by the invention be better than two schemes of the prior art mainly following some: 1, do not change existing IEEE 802.11 agreements, can continue to use such as AP or STA among the existing WLAN; 2, the AC that use the to be provided with management control model of carrying out makes control WLAN effectively simple more; 3,, clearly provide the fine or not standard of assessment communication channel quality by the communication channel quality definition; 4,, clearly provide the validity of dynamic frequency selection algorithm by theory analysis and simulating, verifying.

The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being made within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.

Claims (9)

1, a kind of system that prevents WLAN (wireless local area network) WLAN self-interference, this system comprises a plurality of site STA of access point AP and its administration, it is characterized in that, this system comprises that also centralized control platform AC is connected with AP, be used for detecting and obtain the presently used communication channel quality of AP, by the administration order of Simple Network Management Protocol transmission to AP, make AP adjust presently used communication channel, described AC detects and obtains the presently used communication channel quality of AP is by sending packet for one of them STA that AP administered, writing down the number of data packets that sends, the time delay of packet and the number of dropped packets of packet calculate.

2, a kind of method that prevents the WLAN self-interference is characterized in that, AC is set in WLAN, and this method also comprises:

A, AC send packet to one of them STA that AP administered, send the time delay of number of data packets, packet and the number of dropped packets of packet according to obtaining and calculate the current channel quality value of using communication channel of AP, determine whether this channel quality value that calculates reaches the definite value of the communication channel of adjusting the current use of AP, if, execution in step B; Otherwise, return steps A and continue to carry out;

B, AC send to AP current communication channel are adjusted to the current administration order of using the adjacent communication channel of communication channel of AP, and AP adjusts to the current adjacent communication channel that uses communication channel of AP with current communication channel after receiving this administration order.

3, method as claimed in claim 2 is characterized in that, before steps A, this method also comprises:

AC obtains the STA address list of its administration and decides the interval by AP, from the STA address list behind STA of picked at random, and execution in step A.

4, method as claimed in claim 2 is characterized in that, the described packet of steps A sends surely at interval at setting cycle, and this setting transmission cycle is that AC gets access to by AP,

Steps A is described to obtain the time delay of the number of data packets that sends, packet and the number of dropped packets of packet is the mean value of setting in the transmission cycle.

5, method as claimed in claim 2 is characterized in that, the described packet of steps A is the Ping bag.

6, method as claimed in claim 2 is characterized in that, before the described definite value that determines whether to reach the communication channel of adjusting the current use of AP of steps A, this method also comprises:

AC determines whether to reach the enabling gate limit value and starts the STA number according to the startup thresholding that gets access to from AP, if then the subsequent step of A is carried out in continuation; Otherwise, return steps A.

7, method as claimed in claim 2 is characterized in that, the described AP of calculating of steps A is current, and to use the channel quality value of communication channel be basis $Q\left(f\right)=p/N+\frac{1-p}{N}(t-t_0)/(T-t_0)$ Obtain:

As Q (f) when being not more than 1, do not adjust the presently used communication channel of AP;

Wherein, f represents that the employed frequency of AP, N represent that AC sends out the sum of packet, and p represents AC packet discard sum, t ₀Receive the average delay of packet during expression communication channel idle condition, t represents that AC receives the average delay of packet, and T is the threshold value that sets, and Q (f) is the channel quality value of the communication channel of the current use of AP.

8, method as claimed in claim 2 is characterized in that, before step B, this method also comprises:

AC measures the current channel quality that uses the adjacent communication channel of communication channel of AP, judges that whether the channel quality value obtain deducts AC by the confidence level that AP obtained less than 1, if, execution in step B then; Otherwise, change steps A over to and continue to carry out.

9, method as claimed in claim 8 is characterized in that, described AC measures the current channel quality process of the adjacent communication channel of communication channel of using of AP and is:

AC sends the time delay of number of data packets, packet and the number of dropped packets of packet and adopts to adopting the current STA of the adjacent communication channel of communication channel that uses of AP to send packet according to obtaining $Q\left(f\right)=p/N+\frac{1-p}{N}\left(t{-t}_0\right)/(T-t_0)$ Obtain channel quality value;

Wherein, f represents that the employed frequency of AP, N represent that AC sends out the sum of packet, and p represents AC packet discard sum, t ₀Receive the average delay of packet during expression communication channel idle condition, t represents that AC receives the average delay of packet, and T is the threshold value that sets, Q (f) by AP current the channel quality of adjacent communication channel of use communication channel.

Images