CN110730477B - Adaptive adjustment method of access point based on load balancing - Google Patents

Abstract

The present invention discloses a method for self-adaptive adjustment of access points based on load balancing, comprising the following steps: S10, obtaining position information of each wireless access point, and user position and received signal strength information in the wireless access point; S20 , to count the number of users in each wireless access point, and calculate the average user throughput of each wireless access point; S30, set the minimum average user throughput threshold, and divide the wireless access points into unsaturated wireless access points according to the threshold point and saturated wireless access point; S40, select the distribution wireless access point from the saturated wireless access point, select the receiving wireless access point from the unsaturated wireless access point; S50, select from the distribution wireless access point A user offloads to the receiving wireless access point. The invention solves the problem of uneven user load among multiple wireless access points, and proposes an access point self-adaptive adjustment method for load balancing considering user distribution.

Description

Adaptive adjustment method of access point based on load balancing

technical field

The invention belongs to the field of wireless communication, and in particular relates to an access point self-adaptive adjustment method based on load balancing.

Background technique

The wireless access point is a very important technical means for users to access the network, and it is also a necessary device for users to transmit information. There are many factors that affect the quality of user experience, not only related to information delay, inter-band interference, and the number of terminals used by users, but also related to the location of wireless access points, the size of the transmission power, and the coverage area. Therefore, it is of great significance to study the deployment of wireless access points and the power, coverage adjustment, and the number of devices loaded by wireless access points for user quality of experience.

There are many commonly used wireless access point deployment and follow-up power and coverage adjustment methods, but most of them follow two power setting and coverage adjustment principles: 1. Under the premise of ensuring coverage, make the wireless access point power as much as possible Possibly small; 2. Make the coverage as large as possible while ensuring the power of the wireless access point. However, although the above two principles can achieve good results in ensuring area coverage, in many cases, because users tend to use wireless access points with better connection performance, it will cause a wireless access point with better performance. A wireless access point centrally connects most users, while its neighboring wireless access points connect a few users. Currently there is a technology based on wireless access point switch control to adjust power and coverage to deal with the service area by turning off the wireless access points with too few service users and assigning users to adjacent wireless access points There are no users or too few users. However, this method also has limitations. It is only applicable to the situation where the number of users is too rare, and it is not suitable for the problem that the number of users is moderate and the user load is uneven.

Contents of the invention

In view of the above technical problems, the present invention provides a method for adaptive adjustment of access points based on load balancing, including the following steps:

S10, acquiring the location information of each wireless access point and the location and received signal strength information of the user in the wireless access point;

S20, count the number of users in each wireless access point, and calculate the average user throughput of each wireless access point;

S30, setting a minimum average user throughput threshold, and dividing wireless access points into unsaturated wireless access points and saturated wireless access points according to the threshold;

S40. Select a distribution wireless access point from the saturated wireless access points, and select a receiving wireless access point from the unsaturated wireless access points;

S50. Select a user from the distribution wireless access point to offload to the receiving wireless access point.

Preferably, obtaining the location information of each wireless access point and the location and received signal strength information and calculation of users in the wireless access point includes the following steps:

S11, acquire the location of the user terminal, and calculate the distance from the user to the wireless access point AP _k , assuming that (X _k , Y _k ) is the location coordinate of AP _k , and (x _m , y _m ) is the location coordinate of UE _m , The distance d _mk between UE _m and AP _k can be obtained by the following formula:

S12, calculate the received signal strength RSS of the user according to the distance d _mk , obtained by the following formula:

RSS _mk ＝P _t (k)-L(d _mk )+G _t (k)+G _r (m) (2)

Among them, P _t (k) is the transmit power of AP _k , G _t (k) is the transmit gain of AP _k , G _r (m) is the receive gain of UE _m , RSS _mk is the receive power obtained by UE _m from AP _k , L(d _mk ) is the space loss;

S13, L(d _mk ) is obtained by the following formula:

L(d _mk )＝32.45+20lgf+20lgd _mk (3)

Wherein, f is the frequency of the frequency band where AP _k is located.

Preferably, said counting the number of users in each wireless access point, calculating the average user throughput of each wireless access point includes the following steps:

S21, calculate the total user throughput of each wireless access point, obtained by the following formula:

Among them, E[P] is the average packet length, T _σ is the interval of empty time slots, T _c is the time when the channel is busy due to collision, T _s is the time when the channel is busy due to successful transmission, and P _tr is a given The probability that at least one data packet is transmitted in the time slot;

S22, P _tr is obtained by the following formula:

P _tr =1-(1-τ) ⁿ (5)

where τ is the transmission probability of each user;

S23, P _s is the probability that no collision event occurs in the channel, obtained by the following formula:

P _s ＝nτ(1-τ) ^n-1 /P _tr (6)

S24. Divide formula (4) by the number of users to obtain the average user throughput of each wireless access point.

Preferably, the classifying the wireless access points into unsaturated wireless access points and saturated wireless access points according to the threshold is, taking the wireless access points smaller than the threshold as unsaturated wireless access points, and the wireless access points larger than the threshold as saturated wireless access points point.

Preferably, the selection of the offload wireless access point from the saturated wireless access point is to select the wireless access point with the smallest throughput from the saturated wireless access point as the offload wireless access point, denoted as AP _i* .

Preferably, the selecting the receiving wireless access point from the unsaturated wireless access point includes the following steps:

S41, find the adjacent wireless access point of AP _i* , expressed by the adjacency matrix A, and calculate the throughput difference Δ between AP _i* and the adjacent wireless access point, obtained by the following formula:

Among them, g is the adjacent wireless access point; N _g is the number of users of the adjacent wireless access point; R(N _g ) is the total user throughput of the adjacent wireless access point; User, average user throughput change value;

S42. Select the wireless access point corresponding to the maximum value from Δ as the receiving wireless access point, denoted as AP _j* .

Preferably, the selecting a user from the distribution wireless access point to offload to the receiving wireless access point includes the following steps:

S51, find the public users in the coverage overlapping range of AP _i* and AP _j* , and the private users in the non-overlapping range;

S52, if there is a public user in S51, then preferentially select a user with the lowest signal reception strength from the public users of AP _i* to offload to AP _j* ;

S53. If there is no public user, select a user closest to AP _j* from the users of AP _i* , calculate the distance from the user to AP _j* , and switch the user to AP _j* .

Preferably, if there is no public user, select a user closest to AP _j* from the users of AP _i* , calculate the distance from the user to AP _j* , and first adjust the transmit power of AP _j* so that After the coverage includes the user, the user is switched to AP _j* .

Adopting the present invention has the following beneficial effects: the user access scheme based on load balancing provided by the present invention achieves the purpose of load balancing by switching the wireless access point connected to the user. During the implementation process, the present invention proposes to distinguish user According to the method of user location, users are divided into public users and exclusive users. Further, in view of the characteristic that public users are located between the overlapping ranges of two wireless access points, the public users are directly switched, and for exclusive users, the present invention proposes to adjust the transmission of wireless access points according to the location of the user to be switched. Power and coverage, and then switch users, and finally achieve the effect of load balancing between wireless access points and wireless access points.

Description of drawings

Fig. 1 is the load balancing experimental model figure of the embodiment of the present invention;

FIG. 2 is a flow chart of steps of a load balancing-based access point adaptive adjustment method according to an embodiment of the present invention;

FIG. 3 is a flow chart of the steps of the load balancing-based access point adaptive adjustment method S40 according to an embodiment of the present invention;

FIG. 4 is a flow chart of steps S50 in the load balancing-based access point adaptive adjustment method according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of the maximum coverage of a wireless access point in a load balancing-based access point adaptive adjustment method according to an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Referring to Fig. 1, the experimental environment of the present invention is 6 wireless access points, represented by AP, there are different users in each AP, this network supports IEEE 802.11 protocol and works on the 5GHz frequency band, and there are multiple bandwidths in the frequency band As a 20MHZ channel, each AP can flexibly choose an available channel with less interference for transmission. There are differences in the number of users in each AP. In order to better illustrate the function of the present invention, it is assumed that there are many and few users in the AP.

Referring to Fig. 2, the present invention discloses a method for adaptive adjustment of access points based on load balancing, comprising the following steps:

S10, acquiring location information of each wireless access point and location information of a user of the wireless access point;

S20, count the number of users in each wireless access point, and calculate the average user throughput of each wireless access point;

S30, setting a minimum average user throughput threshold, and dividing wireless access points into unsaturated wireless access points and saturated wireless access points according to the threshold;

S40. Select a distribution wireless access point from the saturated wireless access points, and select a receiving wireless access point from the unsaturated wireless access points;

S50. Select a user from the distribution wireless access point to offload to the receiving wireless access point.

In a specific embodiment, S10, obtaining the location information of each wireless access point and the location and received signal strength information of the user in the wireless access point includes the following steps:

S11, acquire the location of the user terminal, and calculate the distance from the user to the wireless access point AP _k , assuming that (X _k , Y _k ) is the location coordinate of AP _k , and (x _m , y _m ) is the location coordinate of UE _m , The distance d _mk between UE _m and AP _k can be obtained by the following formula:

S12, calculate the received signal strength RSS of the user according to the distance d _mk , obtained by the following formula:

RSS _mk ＝P _t (k)-L(d _mk )+G _t (k)+G _r (m) (2)

Among them, P _t (k) is the transmit power of AP _k , G _t (k) is the transmit gain of AP _k , G _r (m) is the receive gain of UE _m , RSS _mk is the receive power obtained by UE _m from AP _k , L(d _mk ) is the space loss;

S13, L(d _mk ) is obtained by the following formula:

L(d _mk )＝32.45+20lgf+20lgd _mk (3)

Wherein, f is the frequency of the frequency band where AP _k is located.

S20, counting the number of users in each wireless access point, and calculating the average user throughput of each wireless access point includes the following steps:

S21, calculate the total user throughput of each wireless access point, obtained by the following formula:

Among them, E[P] is the average packet length, T _σ is the interval of empty time slots, T _c is the time when the channel is busy due to collision, T _s is the time when the channel is busy due to successful transmission, and P _tr is a given The probability that at least one data packet is transmitted in the time slot;

S22, P _tr is obtained by the following formula:

P _tr =1-(1-τ) ⁿ (5)

where τ is the transmission probability of each user;

S23, P _s is the probability that no collision event occurs in the channel, obtained by the following formula:

P _s ＝nτ(1-τ) ^n-1 /P _tr (6)

S24. Divide formula (4) by the number of users to obtain the average user throughput of each wireless access point.

S30. Divide the wireless access points into unsaturated wireless access points and saturated wireless access points according to the threshold, and use the wireless access points smaller than the threshold as unsaturated wireless access points and the wireless access points larger than the threshold as saturated wireless access points.

S40, select the offload wireless access point from the saturated wireless access point, S401, select the wireless access point with the smallest throughput from the saturated wireless access point, as the offload wireless access point, denoted as AP _i* ;

S41, find the adjacent wireless access point of AP _i* , expressed by the adjacency matrix A, and calculate the throughput difference Δ between AP _i* and the adjacent wireless access point, obtained by the following formula:

Among them, g is the adjacent wireless access point; N _g is the number of users of the adjacent wireless access point; R(N _g ) is the total user throughput of the adjacent wireless access point; User, average user throughput change value;

S42. Select the wireless access point corresponding to the maximum value from Δ as the receiving wireless access point, denoted as AP _j* .

S50, selecting a user from the distribution wireless access point to offload to the receiving wireless access point, including the following steps:

S51, find the public users in the coverage overlapping range of AP _i* and AP _j* , and the private users in the non-overlapping range;

S52, if there is a public user in S51, then preferentially select a user with the lowest signal reception strength from the public users of AP _i* to offload to AP _j* ;

S53. If there is no public user, select a user closest to AP _j* from the users of AP _i* , calculate the distance from the user to AP _j* , and switch the user to AP _j* .

In a specific embodiment, in S53, if there is no public user, select a user closest to AP _j* from the users of AP _i* , calculate the distance from the user to AP _j* , and first adjust the transmit power of AP _j* , after the coverage includes the user, the user is switched to AP _j* .

The power adjustment mentioned above is limited. See Figure 5. AP ₂ is a wireless access point that needs to adjust its coverage. The distances from its neighbors AP ₁ and AP ₃ are l ₁ and l ₂ respectively. The smallest distance between the two is as a critical value for the maximum coverage radius.

Extending the above model to more APs is:

R＝min{l ₁ ,l ₂ ,l ₃ ······l _k } (8)

Among them, l _k is the radius of the adjacent AP.

Let the received signal strength of the user farthest from the wireless access point after switching be ε, and the distance from the user to the wireless access point be the coverage radius, then the adjusted transmit power calculation formula is:

P _t ＝ε+L(r)-G _t -G _r , r≤R (9)

Among them, r is the adjusted coverage radius, and R is the critical value of the maximum coverage radius.

Steps S10-S50 are repeated until the average user throughput of all wireless access points reaches above the threshold set in step S30.

It should be understood that the exemplary embodiments described herein are illustrative and not restrictive. Although one or more embodiments of the present invention have been described in conjunction with the drawings, it will be appreciated by those of ordinary skill in the art that various changes may be made without departing from the spirit and scope of the invention as defined by the appended claims. Changes in form and detail.

Claims (2)

1. A method for adaptive adjustment of access points based on load balancing, characterized in that, comprising the following steps: S10, acquiring the location information of each wireless access point and the location and received signal strength information of the user in the wireless access point; S20, count the number of users in each wireless access point, and calculate the average user throughput of each wireless access point; S30, setting a minimum average user throughput threshold, and dividing wireless access points into unsaturated wireless access points and saturated wireless access points according to the threshold; S40. Select a distribution wireless access point from the saturated wireless access points, and select a receiving wireless access point from the unsaturated wireless access points; S50, selecting a user from the distribution wireless access point to offload to the receiving wireless access point; The acquisition of the location information of each wireless access point and the location and received signal strength information of users in the wireless access point includes the following steps: S11, acquire the location of the user terminal, and calculate the distance from the user to the wireless access point AP _k , assuming that (X _k , Y _k ) is the location coordinate of AP _k , and (x _m , y _m ) is the location coordinate of UE _m , The distance d _mk between UE _m and AP _k can be obtained by the following formula:

S12, calculate the received signal strength RSS of the user according to the distance d _mk , obtained by the following formula: RSS _mk ＝P _t (k)-L(d _mk )+G _t (k)+G _r (m) (2) Among them, P _t (k) is the transmit power of AP _k , G _t (k) is the transmit gain of AP _k , G _r (m) is the receive gain of UE _m , RSS _mk is the receive power obtained by UE _m from AP _k , L(d _mk ) is the space loss; S13, L(d _mk ) is obtained by the following formula: L(d _mk )＝32.45+20lgf+20lgd _mk (3) Wherein, f is the frequency of the frequency band where AP _k is located; Described counting the number of users in each wireless access point, calculating the average user throughput of each wireless access point comprises the following steps: S21, calculate the total user throughput of each wireless access point, obtained by the following formula:

Among them, E[P] is the average packet length, T _σ is the interval of empty time slots, T _c is the time when the channel is busy due to collision, T _s is the time when the channel is busy due to successful transmission, and P _tr is a given The probability that at least one data packet is transmitted in the time slot; S22, P _tr is obtained by the following formula: P _tr =1-(1-τ) ⁿ (5) where, τ is the transmission probability of each user; S23, P _s is the probability that no collision event occurs in the channel, obtained by the following formula: P _s ＝nτ(1-τ) ^n-1 /P _tr (6) S24, divide formula (4) by the number of users to obtain the average user throughput of each wireless access point; The said dividing the wireless access point into unsaturated wireless access point and saturated wireless access point according to the threshold is that the wireless access point smaller than the threshold is regarded as the unsaturated wireless access point, and the wireless access point greater than the threshold is regarded as the saturated wireless access point; The selection of the distribution wireless access point from the saturated wireless access point is to select the wireless access point with the smallest throughput from the saturated wireless access point, as the distribution wireless access point, denoted as AP _i* ; The selecting the receiving wireless access point from the unsaturated wireless access point includes the following steps: S41. Find the adjacent wireless access point of AP _i* , express it in the adjacency matrix A, and calculate the difference △ between the throughput of AP _i* and the adjacent wireless access point, which is obtained by the following formula:

Among them, g is the adjacent wireless access point; N _g is the number of users of the adjacent wireless access point; R(N _g ) is the total user throughput of the adjacent wireless access point; User, average user throughput change value; S42, select the wireless access point corresponding to the maximum value from Δ, as the receiving wireless access point, denoted as AP _j* ; The step of selecting a user from the distribution wireless access point to offload to the receiving wireless access point includes the following steps: S51, find the public users in the coverage overlapping range of AP _i* and AP _j* , and the private users in the non-overlapping range; S52, if there is a public user in S51, then preferentially select a user with the lowest signal reception strength from the public users of AP _i* to offload to AP _j* ; S53. If there is no public user, select a user closest to AP _j* from the users of AP _i* , calculate the distance from the user to AP _j* , and switch the user to AP _j* . 2. A method for self-adaptive adjustment of access points based on load balancing as claimed in claim 1, wherein if there is no public user, then select one from the users of AP _i* that is closest to AP _j* Calculate the distance between the user and AP _j* , first adjust the transmit power of AP _j* to cover the user, and then switch the user to AP _j* .

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