FR3146256A1 - Method for automatically selecting the operating channel of a WIFI access point. - Google Patents

Abstract

The invention presents a method for automatically selecting the operating channel of a WIFI access point belonging to a local network of access points, comprising a step of initializing the choice of a channel consisting of scanning the available channels and selecting the least used channel, characterized in that the following are measured episodically: The electrical consumption of the electronic circuit of at least one of said access points The number of users connected to said access point The bandwidth distributed by said at least one of said access points And that the channel change of said access point is controlled when the result of a function using the three aforementioned values exceeds a threshold value and/or the power drop of at least one neighboring access point and/or the channel change of at least one neighboring access point. Single Figure

Description

Method for automatically selecting the operating channel of a WIFI access point. Field of invention

The present invention relates to the field of wireless computer networks, in particular WIFI networks or radio bridges.

The proliferation of WiFi networks based on the IEEE 802.11 wireless RLAN (radio local area network) standard, commercially known as WiFi® has led to the availability of multiple WiFi-enabled devices and low-cost integrated circuits implementing various aspects of the IEEE 802.11 standards. This makes them attractive for delivering "last mile" voice and data services from a fiber backbone to end users in sparsely populated rural areas, or generally in areas where existing alternatives for delivering "last mile" services, such as WIMAX, terrestrial telephone line networks, cable TV and fiber optic solutions are too expensive or otherwise impractical.

A large number of connected devices integrate a Wi-Fi connection (smartphones, computers, internet boxes, home automation devices, etc.) and Wi-Fi technology thus meets the need of users to connect everywhere. Mobile traffic now represents more than 50% of internet traffic. With an economic advantage: unlike 3G/4G, the use of Wi-Fi frequencies is most often free for the user. Less expensive to create than a wired network, public Wi-Fi is attracting more and more communities or private operators, for example operators of campsites or leisure residences, or business parks. Equipping a site makes it possible to promote access to dematerialized public services, to audiovisual services, to develop the visibility of local events and to strengthen the economic and tourist attractiveness of the site.

However, the WiFi signal has a limited range of a few dozen meters and is sensitive to obstacles and interference.

Interference results from multiple causes that can occur unexpectedly, such as electromagnetic radiation from equipment introduced near an access point or coming into operation, for example a baby monitor, a security camera, a microwave oven, another Wifi access point controlled by a third party, or even certain Bluetooth equipment that also uses the 2.4 GHz frequency used by Wifi, in competition with the 5 GHz band.

The consequences of interference are the degradation of signal quality, the drastic reduction of flow rate and even the loss of connection of equipment dependent on the disrupted access point.

In the event of a degradation in the quality of the Wi-Fi signal, the usual procedure is to change the channels of the access points controlled by the operator to select a less congested channel for each of the controlled access points. Of course, for an operator who controls several access points on the same network, changing the channel of one of the access points can cause new interference with another access point that was already using this channel, and the problem can thus propagate recursively.

State of the art

Changing the channels of a set of access points controlled by an operator is a tedious task, especially since interference can occur at any time, which requires constant monitoring and very high responsiveness. It has of course been proposed to automate the detection of interference suffered by one or more access points in the same network.

For example, patent US8923225 proposes a method for avoiding interference in a WiFi network comprising a plurality of WiFi terminals, consisting of:

a) using one or more of the WiFi terminals to collect radio interference information, wherein the radio interference information comprises packet header information for WiFi packets received on a plurality of WiFi channels;

(b) communicating radio interference information from one or more of the WiFi terminals to a network management system (NMS) for storage in a network radio environment database (NRED); and,

(c) receiving transmission and reception parameters sent by the NMS to one or more of the WiFi terminals for use thereof in WiFi data communications by said one or more of the WiFi terminals in order to avoid or reduce radio interference in the WiFi network;

wherein a) comprises collecting, by the one or more of the WiFi terminals, packet header information from WiFi packets received by the one or more WiFi terminals on the plurality of WiFi channels, and wherein b) comprises communicating to the NMS the packet header information that is collected by the one or more WiFi terminals from the received WiFi packets as part of the radio interference information.

This solution is not entirely satisfactory because it involves the use of unconventional WIFI terminals, adapted to the collection of transmission and reception parameters. These specific terminals differ from conventional Wi-Fi terminals in at least two important aspects:

(a) they include means for detecting interfering radio signals at a variety of RF frequencies within the operating frequency range of the network to obtain Wi-Fi and other RF interference information at their respective locations, and

b) they use a new TDD/TDM (time domain duplexing/time domain multiplexing) mechanism to coordinate their transmission and reception to avoid interference between conventional terminals. These specific terminals include conventional PHY-level hardware for processing communication packets, but employ a new transmission synchronization algorithm.

• le gestionnaire de réseau (GW1, GW2, GW3) de chaque réseau d'accès radio (RAN1, RAN2, RAN3) exécute un processus d'attribution de spectre pour l'attribution de sous-canaux à ses nœuds ;
• les nœuds (BS1, ...BS5; BS6, ...BS10 ; BS11, ...BS16) de chaque réseau d'accès radio (RAN1, RAN2, RAN3) exécutent une communication sans fil en utilisant les sous-canaux qui leur sont attribués ;
• le gestionnaire de réseau (par exemple, GW1) d'un réseau d'accès radio (RANC1) estime un niveau de brouillage attendu en interne dans le réseau d'accès radio pendant ladite communication sans fil et reçoit, en provenance de ses nœuds associés (BS1, ...BS5), des données indiquant les niveaux réels de brouillage subis par les nœuds et affectant les sous-canaux qui leur sont attribués, ledit brouillage survenant tant en interne dans le réseau d'accès radio (RAN1) qu' en externe en provenance des autres réseaux d'accès radio (RAN2, RAN3) ;
• le gestionnaire de réseau (GW1) dudit réseau d'accès radio (RAN1) compare une somme desdits niveaux réels de brouillage audit niveau de brouillage en déterminant si ladite somme excède ledit niveau d'au moins un seuil déterminé pour déterminer si une coordination avec un autre gestionnaire de réseau (GW2, GW3) est nécessaire pour réduire le brouillage survenant en externe et, si tel est le cas :
• le gestionnaire de réseau (GW1) dudit réseau d'accès radio (RAN1) notifie cette nécessité, ainsi qu'une liste des sous-canaux affectés, au gestionnaire de réseau (GW2, GW3) d'au moins l'un des autres réseaux d'accès radio (RAN2, RAN3) ; et
• le gestionnaire de réseau (GW2, GW3) créé un autre réseau d'accès radio (RAN2, RAN3) exécute de nouveau le processus d'assignation de spectre sur ses nœuds associés (BS6, ...BS10 ; BS11, ...BS16) en fonction de ladite liste des sous-canaux affectés pour réduire le niveau de brouillage subi par les nœuds (BS1, ...BS5) via le réseau d'accès radio (RAN1).

Patent EP2083594B1 proposes another method for reducing interference in a wireless communication system formed by a plurality of radio access networks (RAN1, RAN2, RAN3), each radio access network having a network manager (GW1, GW2, GW3) adapted to communicate with a plurality of nodes (BS1, ...BS5; BS6, ...BS10; BS11, ...BS16) associated with the network manager, and each radio access network having a frequency spectrum divisible into a plurality of subchannels used by the nodes for wireless communication, said frequency spectrum at least partially overlapping the frequency spectrum of one or more other radio access networks. This method comprises the following steps:

• the network manager (GW1, GW2, GW3) of each radio access network (RAN1, RAN2, RAN3) performs a spectrum allocation process for the allocation of subchannels to its nodes;
• the nodes (BS1, ...BS5; BS6, ...BS10; BS11, ...BS16) of each radio access network (RAN1, RAN2, RAN3) perform wireless communication using the subchannels assigned to them;
• the network manager (e.g. GW1) of a radio access network (RANC1) estimates an expected interference level internally in the radio access network during said wireless communication and receives, from its associated nodes (BS1, ...BS5), data indicating the actual interference levels experienced by the nodes and affecting the subchannels assigned to them, said interference occurring both internally in the radio access network (RAN1) and externally from the other radio access networks (RAN2, RAN3);
• the network manager (GW1) of said radio access network (RAN1) compares a sum of said actual interference levels to said interference level by determining whether said sum exceeds said level by at least a determined threshold to determine whether coordination with another network manager (GW2, GW3) is necessary to reduce the interference occurring externally and, if so:
• the network manager (GW1) of said radio access network (RAN1) notifies this need, together with a list of the assigned subchannels, to the network manager (GW2, GW3) of at least one of the other radio access networks (RAN2, RAN3); and
• the network manager (GW2, GW3) creates another radio access network (RAN2, RAN3) performs the spectrum assignment process again on its associated nodes (BS6, ...BS10; BS11, ...BS16) based on said list of assigned subchannels to reduce the interference level suffered by the nodes (BS1, ...BS5) via the radio access network (RAN1).

This solution also requires having direct information on the level of interference.

Japanese patent JP5189160B2 proposes a method for suppressing common frequency interference in a wireless communication system. This method is applicable to a system comprising a main control module and at least two cellular base stations, wherein the main control module interacts with each cellular base station regarding the interference suppression information and obtains the interference terminal information in each cell; the main control module collects the interference terminal information in each cell, determines the interference suppression scheduling method, and sends the interference terminal information and the interference suppression scheduling method to the corresponding cellular base station; each cellular base station performs scheduling according to the interference suppression scheduling method sent by the main control module in combination with the scheduling requirement in the local cell. The present invention can effectively avoid common frequency interference between cells, improve the reception performance of users at the edge of cells, increase the cell coverage, and improve the system throughput and spectrum efficiency.

US20140226572A1 relates to a wireless access point (AP) that stores a regional code identifying a country/region where said wireless AP is intended to operate. This regional code may be provided by the vendor of the wireless AP or in response to information communicated either by the user of the wireless AP or by a GPS receiver. In response to the regional code, the wireless AP identifies one or more WiFi channels exposed to interference in the region due to non-WiFi wireless communication channels approved for use in the region. The wireless AP then selects a WiFi channel intended for wireless communication, avoiding selecting WiFi channels identified as exposed to interference in the region.

This solution is based on learning and has the disadvantage of a static solution that does not take into account fluctuations in usage. The channel is selected from a database, but does not provide solutions for the unexpected appearance of disruptive equipment.

US8914055 provides a network node configured to select resources for a direct communication link between a first wireless device and a second wireless device in a cellular communication network, comprising: a transceiver subsystem configured to enable wireless communication; and

• sélectionner une ressource de liaison descendante du réseau de communication cellulaire en tant que ressource pour la liaison de communication directe de dispositif à dispositif entre le premier dispositif sans fil et le second dispositif sans fil si une station de base desservant le premier dispositif sans fil et une station de base desservant le second dispositif sans fil sont équipées avec un récepteur d'annulation d'interférence et à la fois une distance radio entre le premier dispositif sans fil et la station de base desservant le premier dispositif sans fil et une distance radio entre le second dispositif sans fil et la station de base desservant le second dispositif sans fil sont inférieures à une distance radio seuil prédéfinie ; et
• sélectionner une ressource de liaison montante du réseau de communication cellulaire comme ressource pour la liaison de communication directe de dispositif à dispositif entre le premier dispositif sans fil et le second dispositif sans fil si la station de base desservant le premier dispositif sans fil et la station de base desservant le second dispositif sans fil sont équipées avec un récepteur d'annulation d'interférence et au moins l'une parmi la distance radio entre le premier dispositif sans fil et la station de base desservant le premier dispositif sans fil et la distance radio entre le second dispositif sans fil et la station de base desservant le second dispositif sans fil est supérieure à la valeur prédéfinie seuil de distance radio.: utilise un « client » comme mandataire pour éviter de se connecter en cas d’interférence : nécessite d’avoir accès à un autre client.

a processing subsystem configured to:

• selecting a downlink resource of the cellular communication network as a resource for the direct device-to-device communication link between the first wireless device and the second wireless device if a base station serving the first wireless device and a base station serving the second wireless device are equipped with an interference cancellation receiver and both a radio distance between the first wireless device and the base station serving the first wireless device and a radio distance between the second wireless device and the base station serving the second wireless device are less than a predefined threshold radio distance; and
• selecting an uplink resource of the cellular communication network as a resource for the direct device-to-device communication link between the first wireless device and the second wireless device if the base station serving the first wireless device and the base station serving the second wireless device are equipped with an interference cancellation receiver and at least one of the radio distance between the first wireless device and the base station serving the first wireless device and the radio distance between the second wireless device and the base station serving the second wireless device is greater than the predefined radio distance threshold value.: uses a "client" as a proxy to avoid connecting in the event of interference: requires access to another client.

Disadvantages of the prior art

These solutions are not entirely satisfactory because they require the use of specific hardware for network administration.

Solution provided by the invention

1. La consommation électrique du circuit électronique d’au moins l’un desdits point d’accès
2. Le nombre d’utilisateurs connectés audit point d’accès
3. La bande passante distribuée par ledit au moins desdits point d’accès

In order to overcome this drawback, the invention relates, in its most general sense, to a method for automatically selecting the operating channel of a WIFI access point belonging to a local network of access points, comprising a step of initializing the choice of a channel consisting of scanning the available channels and selecting the least used channel, characterized in that the following are measured episodically:

1. The power consumption of the electronic circuit of at least one of said access points
2. The number of users connected to said access point
3. The bandwidth distributed by said at least one of said access points

And we control the channel change of said access point when the result of a function using the three aforementioned values exceeds a threshold value and/or the drop in power of at least one neighboring access point and/or the channel change of at least one neighboring access point.

Advantageously, a scan of the transmission channels of each of said neighboring access points is furthermore ordered to order the channel change of said access point when the result of a function using the three aforementioned values exceeds a threshold value and/or the drop in power of at least one neighboring access point and/or the channel change of at least one neighboring access point.

Preferably, said initialization step consists in ordering a scan of the transmission channels of neighboring access points to select the new channel of one of said access points.

According to a variant, the reduction of the transmission power of said access point in question is also ordered when the result of a function using the three aforementioned values exceeds a threshold value [to reduce the number of connected users].

Preferably, the consumption (POE), bandwidth and number of users (ARP table) values are measured at the switch to which the WIFI access point is connected.

According to a particular implementation mode, an alert signal is commanded when the result of a function exploiting the three aforementioned values exceeds a threshold value.

Detailed description

There represents the schematic topology of a local network of WIFI access points, comprising three access points (1, 2, 3) connected to a switch (10) by wired links (11, 12, 13).

The switch (10) includes, in a known manner, probes for each port, allowing data to be retrieved via an SSH, TELNET, or CLI type connection, with lines of code specific to the switch (10) manufacturer, from a server (20) connected to the switch (10).

This server (20) connects to the switch (10) and initially controls the initialization step of the local network. This initialization consists for example in assigning a channel C ₁ to the first access point (1), randomly or from a predefined base, or from an environment scan of third-party access points, not controlled by the switch (10) and broadcasting a wifi signal on the same area covered by the controlled local network.

The other access points (2, 3) are configured by the server (20) by a choice of channel C _i so as to reduce interference between the access points (1 to 3).

The invention then consists of episodically collecting on the server (20) data measured on the switch (10).

1. La consommation électrique du circuit électronique d’au moins l’un desdits point d’accès
2. Le nombre d’utilisateurs connectés audit point d’accès
3. La bande passante distribuée par ledit au moins desdits point d’accès

This data includes for each of the access points (1 to 3):

1. The power consumption of the electronic circuit of at least one of said access points
2. The number of users connected to said access point
3. The bandwidth distributed by said at least one of said access points

This data is acquired by the server (20) by sending occasional command lines to retrieve the data via the intelligent platform management interface (IPMI) of the access point circuit, for example via a Java applet.

If an interference source appears (4), in the in the coverage area of the access point (3), the power consumption measured on the switch (10) on the port corresponding to the access point (3) will increase and this variation will be detected by the server (20), which will order a change of channel C _i for each of the terminals (1 to 3).

For the access point (3) disturbed by an interference source (4), the new channel will be chosen to be the furthest from the original channel corresponding to the disturbing channel.

The C _i channels of neighboring access points (1, 2) will also be modified if they present a risk of interference between access points (1 to 3).

The server (20) may also command an increase in the transmit power of one or more access points to increase the signal-to-noise ratio in the channel of the interference source (4).

The server (20) can also control the reduction of the transmission power of the access point (3) using the same channel as that of the source of interference (4) in order to reduce the number of connected devices, and force them to be distributed over the neighboring points (1; 2). The server (20) will in this case control the increase in the transmission power of the neighboring terminals (1, 2) within the limits of the maximum authorized powers.

For example, the server (20) determines a variable T corresponding to the interference rate, according to the following formula:

T = L*(P/B)- K*(P/N)

• P désigne la puissance électrique consommée par un point d’accès (1 à 3) mesurée sur le switch (10)
• N désigne le nombre d’équipements connectés à un point d’accès (1à 3)
• B désigne la bande passante consommée par un point d’accès (1 à 3) mesurée sur le switch (10)

Or

• P denotes the electrical power consumed by an access point (1 to 3) measured on the switch (10)
• N denotes the number of devices connected to an access point (1 to 3)
• B denotes the bandwidth consumed by an access point (1 to 3) measured on the switch (10)

K and L are coefficients depending on the installed hardware and WIFI technology.

To determine the L coefficient, tests are carried out consisting of voluntarily generating known interference with a pulse generator, and measuring the impact on the power consumption of an access point concerned.

To determine the L coefficient, a large number of connected devices are connected to one of the access points (1 to 3) in an interference-free environment, and the impact on consumption of the number of connected client devices is measured. This second coefficient is optional.

This variable T of an access point (1) is episodically compared to a threshold value, or the previous value, or even the value T for neighboring access points (2, 3) to conditionally trigger the reconfiguration processing of the channels C _i .

Claims (6)

Method for automatically selecting the operating channel of at least one WIFI access point belonging to a local network of access points, comprising a step of initializing the choice of a channel consisting of scanning the available channels and selectingto nerthe least used channel, characterized in that we measure episodically:

1. The power consumption of the electronic circuit of at least one of said access points
2. The number of users connected to said access point
3. The bandwidth distributed by said at least one of said access points

And we control the channel change of said access point when the result of a function using the three aforementioned values exceeds a threshold value and/or the drop in power of at least one neighboring access point and/or the channel change of at least one neighboring access point. Method for automatically selecting the operating channel of a WIFI access point according to claim 1, characterized in that a scan of the transmission channels of each of said neighboring access points is also controlled to control the change of channel of said access point when the result of a function using the three aforementioned values exceeds a threshold value and/or the drop in power of at least one neighboring access point and/or the change of channel of at least one neighboring access point. Method for automatically selecting the operating channel of a WIFI access point according to claim 1, characterized in that said initialization step consists of controlling a scan of the transmission channels of neighboring access points to select the new channel of one of said access points. Method for automatically selecting the operating channel of a WIFI access point according to claim 1, characterized in that the reduction of the transmission power of said access point in question is also controlled when the result of a function using the three aforementioned values exceeds a threshold value to reduce the number of connected users. Method for automatically selecting the operating channel of a WIFI access point according to claim 1, characterized in that the consumption values (POE), bandwidth and number of users (ARP table) are measured at the level of the switch to which the WIFI access point is connected. Method for automatically selecting the operating channel of a WIFI access point according to claim 1, characterized in that an alert signal is controlled when the result of a function using the three aforementioned values exceeds a threshold value.