KR101639185B1 - method for controlling airtime in wireless LAN network, and computer-readable recording medium for the same - Google Patents

Abstract

The present invention relates to a technique for a WLAN AP to control uplink / downlink airtime, preferably by SSID, in a WLAN network to which at least one station is connected. More specifically, the present invention sets a threshold time for each predetermined airtime management period (e.g., 100 msec bit frame) and compares each threshold time with an uplink / downlink air time monitored in real time, And controlling the traffic of the wireless LAN network accordingly so that the uplink / downlink airtime is adjusted when the time exceeds the threshold time. According to the present invention, an uplink / downlink air time is selectively controlled for each SSID, thereby ensuring a communication quality (Qos) of a certain level or higher to a user belonging to a specific service group (e.g., a specific SSID).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling air time in a wireless LAN network and a recording medium therefor,

The present invention relates to a technique for a WLAN AP to control uplink / downlink airtime, preferably by SSID, in a WLAN network to which at least one station is connected.

More specifically, the present invention sets a threshold time for each predetermined airtime management period (e.g., 100 msec bit frame) and compares each threshold time with an uplink / downlink air time monitored in real time, And controlling the traffic of the wireless LAN network accordingly so that the uplink / downlink airtime is adjusted when the time exceeds the threshold time.

It is very difficult to properly manage the wireless traffic in the WLAN network where the WLAN AP and multiple stations are connected. If some stations generate excessive traffic, other stations connected to the same WLAN AP may experience a significant performance degradation Feeling. Cafes, etc., are connected to one wireless LAN AP.

Since stations connected to one WLAN AP share a network resource called air and a wireless LAN AP, if some stations overload the network resources, problems occur in other stations.

This relationship also occurs between the uplink and the downlink, and when traffic is excessively generated in either the uplink or the downlink, the other side can not properly handle the wireless LAN communication. Especially, if uplink traffic is used excessively, IP set-top box that mainly uses downlink traffic will not provide stable service.

In order to partially solve such a problem, a method of differentially allocating the throughput (amount of transmitted data per unit time) for each SSID has been attempted. This is to suppress the traffic of the SSID assigned with low throughput by allocating the throughput differentially for each SSID and to ensure stable communication service for the SSID assigned high throughput.

However, when traffic is transmitted at a low bit rate due to a device performance problem in a case where a low throughput is allocated, a substantial amount of network resources are consumed in spite of a small amount of data transmitted per unit time. As a result, although other SSIDs are assigned a high throughput, there is a problem that data can not be transmitted and received correctly.

Accordingly, there has been a demand for a technology capable of stably ensuring the radio communication performance of other stations even when some of the multiple stations connected to one WLAN AP are trying to generate excessive traffic. In the present invention, this problem is solved in terms of airtime without dealing with the throughput as in the prior art. However, it is very difficult to control airtime in a wireless LAN network, so sophisticated technology is needed.

Korean Patent Application No. 10-2007-7024178 entitled " Media Time Allocation and Scheduling Using a Superframe of a Two-Handed Zone Structure for Providing QOS in a WLAN Network " Korean Patent Application No. 10-2004-0060165 entitled " Mobile IP system and method using diamond-based dynamic IP allocation in a broadband wireless access communication system such as WiBro " Korean Patent Application No. 10-2011-0047920 "Channel Selection and Communication Method Considering Wi-Fi Interference in Multi-Channel Wireless Sensor Network" Korean Patent Application No. 10-2008-0137787 "Network Sharing Method and System of Mobile Communication Terminal with WiFi Function" Korean Patent Application No. 10-2010-0105168 entitled " Method and Apparatus for Transmitting WLAN Network Sharing Data in Wi-Fi Protected Group " Korean Patent Application No. 10-2009-0000466 "Method and apparatus for differentiating network connection path"

It is an object of the present invention to provide a technique for a WLAN AP to control uplink / downlink air time, preferably by SSID, in a WLAN network to which at least one station is connected.

Particularly, an object of the present invention is to provide a method and apparatus for setting a critical time for each predetermined airtime management cycle (e.g., 100 msec bit frame), comparing the uplink / downlink air time monitored in real time with each threshold time, And to control the traffic of the wireless LAN network in accordance with the threshold time, thereby adjusting the uplink / downlink air time.

According to a first aspect of the present invention, there is provided a method of controlling uplink air time by a wireless LAN AP in a wireless LAN network to which a wireless LAN AP and at least one station are connected, the method comprising the steps of: (a) Setting an uplink threshold time for the management period; (b) monitoring in real time the uplink air time for each airtime management period in a wireless LAN network; (c) comparing the uplink air time and the uplink critical time in real time; (d) identifying an uplink superheat event in which the real-time monitored uplink air time exceeds an uplink threshold time; (e) changing and setting environment parameters of the wireless LAN network in response to the uplink overheating event.

At this time, preferably, in step (a), a threshold time for each uplink SSID is individually set within a range of uplink threshold time for each of a plurality of SSIDs, and for each of the plurality of SSIDs in step (b) The airtime is individually monitored in real time, and the uplink air time monitored in real time for each SSID in step (c) is compared with the threshold time for each uplink SSID, and in step (d) Identifies an overheating event for each uplink SSID exceeding a threshold time for each uplink SSID corresponding to the SSID, and changes and sets environment parameters of the WLAN network in response to the overheating event for each uplink SSID in step (e) .

Preferably, in step (e), the environment parameter is configured to include at least one of an ECW parameter value and an AIFSN parameter value, and the at least one of the ECW parameter value and the AIFSN parameter value is increased or decreased in response to the uplink superheat event, Cast.

A second embodiment of the present invention is a method for a WLAN AP to control a downlink air time in a WLAN network connected to a WLAN AP and at least one station, the method comprising the steps of: (a) Setting a time; (b) monitoring a downlink air time in real time on an air time management cycle in a wireless LAN network; (c) comparing the downlink air time and the downlink critical time that are monitored in real time; (d) identifying downlink superheat events in which the real-time monitored downlink air time exceeds the downlink threshold time; (e) stopping downlink data transmission in the air time management cycle in response to the downlink overheating event.

Preferably, in step (a), the threshold time for each downlink SSID is individually set within the range of the downlink threshold time for each of the plurality of SSIDs. In step (b), for each of the plurality of SSIDs, The downlink air time monitored in real time for each SSID in step (c) and the critical time for each downlink SSID are compared with each other, and the downlink air time monitored in real time for each SSID in step (d) In response to an overheating event for each downlink SSID in step (e), downlink data transmission in the corresponding airtime management cycle of the corresponding SSID Lt; / RTI >

Preferably, the method further comprises: after step (e), (f) resuming the downlink data transmission suspended in the next airtime management cycle.

According to the present invention, there is an advantage that the uplink / downlink air time can be controlled in a wireless LAN network.

In addition, according to the present invention, an uplink / downlink air time is selectively controlled for each SSID, thereby ensuring a communication quality (Qos) of a certain level or more to a user belonging to a specific service group (e.g., a specific SSID).

FIG. 1 is a diagram showing an overall configuration for air time control in a wireless LAN network according to the present invention, FIG.
FIG. 2 illustrates an example of a menu for setting a threshold value of the uplink / downlink air time and a menu for setting a threshold value of the uplink / downlink air time for each SSID in the WLAN AP according to the present invention,
3 is a diagram illustrating a process of real-time measurement of uplink air time according to wireless LAN data reception in the present invention.
4 is a diagram illustrating a process of real-time measurement of downlink air time according to wireless LAN data transmission in the present invention.
FIG. 5 is a diagram illustrating an example of a wireless LAN environment parameter to be set and changed in order to control an uplink air time according to the present invention;
6 is a diagram illustrating a concept of managing downlink air time per SSID according to an airtime management cycle according to the present invention,
FIG. 7 is a flowchart illustrating a process of controlling uplink air time in a wireless LAN network according to the present invention;
FIG. 8 is a flowchart illustrating a process of controlling downlink air time in a wireless LAN network according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a diagram illustrating an overall configuration for air time control in a wireless LAN network according to the present invention. Referring to FIG. 1, a WLAN AP according to the present invention performs uplink and downlink while wirelessly communicating with a plurality of stations STA_1 to STA_9 in a wireless LAN coverage.

A plurality of stations (STA_1 to STA_9) connected to a single WLAN AP share a common network resource, that is, a processor of a transmission medium and a WLAN AP while sharing the same. Accordingly, if the uplink air time is increased, the air time available for the downlink is decreased, while if the downlink air time is increased, the air time available for the uplink is decreased. Likewise, if some stations take up a lot of airtime, the airtime available to other stations is reduced.

Accordingly, in the present invention, the wireless LAN AP controls the ratio or threshold of the air time that can be occupied by the uplink or the downlink, thereby preventing the other of the uplink and the downlink from being greatly disturbed by either one of the uplink and the downlink. Preferably, such airtime control may be performed for each SSID. Accordingly, a plurality of stations connected to one WLAN AP can perform wireless LAN communication in a coordinated manner without being excessively disturbed by each other.

Here, the physical layer of the wireless LAN AP can provide an application program interface (API) for calculating the air time of individual traffic and providing the result value to the hardware or software.

FIG. 2 is a diagram illustrating an example of a menu for setting a threshold value of uplink / downlink air time and a menu for setting a threshold value of uplink / downlink air time for each SSID in a WLAN AP according to the present invention.

Referring to (a) of FIG. 2, the WLAN AP individually measures the uplink air time and the downlink air time thresholds (uplink threshold time and downlink threshold time) individually by, for example, 70% And 30%, respectively.

Referring to (b) of FIG. 2, when the wireless LAN AP provides a plurality of SSIDs, the threshold time ratio for the uplink (e.g., SSID_A = 60% , SSID_B = 30%, and SSID_C = 10%) can be set for each SSID, and the threshold time ratio (e.g., SSID_A = 50%, SSID_B = 30%, SSID_C = 20%) for the downlink can be set for each SSID.

For example, when the airtime management cycle is '100 msec' corresponding to one beacon frame, when the threshold time ratio for the uplink is 60% for SSID_A, 30% for SSID_B, and 10% for SSID_C, Means that SSID_A is allocated as 60 msec, SSID_B is 30 msec, and SSID_C is 10 msec.

In the present invention, the period for managing whether or not the air time of the uplink or the downlink exceeds a predetermined threshold, i.e., the 'airtime management period', is set to an integral multiple of the wireless LAN beacon frame. For example, a beacon frame of 100 msec may be set as an airtime management period, as described above. In addition, three beacon frames can be set in the air time management period. In this case, the airtime management cycle becomes 300 msec. Assuming that the threshold time ratio for the uplink is 60%, the SSID_B is 30%, and the SSID_C is 10%, the threshold time for the uplink is SSID_A of 180 msec , SSID_B is allocated as 90 msec, and SSID_C is allocated as 30 msec.

3 is a diagram illustrating a process of real-time measurement of uplink air time according to wireless LAN data reception in the present invention.

3, the WLAN AP marks the time point (rx_start_time) of the individual uplink air time when the reception of the packet from the station is detected (CCA detect), and then the reception of the data in units of packets is completed (CCA End), it detects this and marks the end point (rx_end_time) of the individual uplink air time.

Then, the uplink air time required to receive one packet or data can be calculated by subtracting the time (rx_start_time) of the uplink air time from the end point (rx_end_time) of the uplink air time.

The individual uplink air time is added to the airtime management cycle (e.g., one beacon frame) to check whether or not the uplink air time exceeds a predetermined threshold (uplink threshold time) in the corresponding air time management cycle .

At this time, the WLAN AP can manage uplink air time by SSID (e.g., SSID_A, SSID_B, SSID_C) separately. Thus, as described above with reference to FIG. 2 (b), it can be checked whether the uplink air time exceeds the uplink critical time set by each SSID.

4 is a diagram illustrating a process of real-time measurement of downlink air time according to wireless LAN data transmission in the present invention.

Referring to FIG. 4, when the WLAN AP detects a packet transmission request to the station (Tx Start), it marks a time point (tx_start_time) of the individual downlink air time while starting packet transmission accordingly, (Tx End (OK)) or a transmission failure is identified (RetryLimit), and marks the end point (tx_end_time) of the individual downlink air time.

If the time point (tx_start_time) of the downlink air time is subtracted from the end point (tx_end_time) of the downlink air time, the downlink air time required to transmit one packet or data can be calculated.

The individual downlink air time is summed over an airtime management period (e.g., one beacon frame) to check whether the downlink air time exceeds a preset threshold (downlink threshold time) in the corresponding air time management period .

At this time, the WLAN AP can manage downlink air time by SSID (e.g., SSID_A, SSID_B, SSID_C). Thus, as described above with reference to FIG. 2 (b), it is possible to check whether the downlink air time exceeds the uplink critical time set by each SSID.

FIG. 5 is a diagram illustrating an example of a wireless LAN environment parameter to be changed in order to control the uplink air time according to the present invention. Referring to FIG. 5, when the WLAN AP monitors the uplink air time in real time, if the actual uplink air time identifies an uplink overheating event exceeding a preset uplink threshold time, the WLAN AP can mitigate it (&Quot; wireless LAN environment parameter ") of the wireless LAN network.

Here, the WLAN environment parameter to be changed and set by the WLAN AP includes at least one of an ECW parameter value and an AIFSN parameter value. By changing the setting of these parameter values, it is possible to control the uplink air time by adjusting the density at which a plurality of stations transmit data to the wireless LAN AP.

For example, if you change the setting of ECW parameter value, 2 ^ECWmin ~ 2 ^{ECW max in} the time span of the packet collision due to collision. That is, increasing the value of 'ECWmin' or 'ECWmax' increases the retransmission delay time that is randomly set when a physical layer collision occurs in the process of transmitting a packet to the WLAN AP by an individual station, Resulting in a decrease in the actual uplink air time induced.

On the other hand, if the value of 'ECWmin' or 'ECWmax' is decreased, a random retransmission delay time is reduced when a physical layer collision occurs in the process of transmitting a packet to an individual station by a corresponding station Resulting in an increase in the actual uplink air time induced.

In addition, setting the AIFSN parameter value results in increasing or decreasing the time interval between frames when the station transmits data to the WLAN AP, thereby reducing or increasing the actual uplink air time caused by the station Lt; / RTI >

FIG. 6 is an exemplary diagram illustrating a concept of managing downlink air time per SSID for each airtime management period according to the present invention. FIG.

Referring to FIG. 6, when the WLAN AP monitors the downlink air time in real time, if the downlink air time identifies a downlink overheating event whose actual downlink air time exceeds a predetermined downlink threshold time, And stops the downlink data transmission in the period (e.g., 100 msec).

At this time, the WLAN AP can monitor the downlink air time for each SSID (for example, SSID_A, SSID_B, SSID_C) and set the downlink threshold time (for example, 50 msec, 30 msec, 20 msec) for each SSID have.

As a result, the downlink overheating event can be identified for each SSID. If the downlink overheating event is identified for each SSID, downlink data transmission is performed within one air time management period (one cycle) as shown in [ After the interruption, the interrupted downlink data transmission is resumed in the next airtime management cycle (2 cycles).

For example, if the WLAN AP recognizes that it has already exhausted the downlink critical time (50 msec) for SSID_A in the first airtime management cycle during transmission of data_A, it stops transmission for data_A. Then, when the corresponding air time management cycle has elapsed and the next air time management cycle is started, the transmission to the stopped data_A is resumed.

7 is a flowchart illustrating a process of controlling an uplink air time in a wireless LAN network according to the present invention.

Step S110: A first embodiment of the present invention is a method for controlling uplink air time by a wireless LAN AP in a wireless LAN network to which a wireless LAN AP and one or more stations are connected, up time (Th-uplink) with respect to the uplink time (-airtime).

On the other hand, when the wireless LAN AP has a plurality of SSIDs, the threshold time (Th-uplink, SSID) for each uplink SSID can be individually set within the range of the uplink threshold time for each of the plurality of SSIDs.

Steps S120 and S130: The uplink air time (T-ul (t)) is monitored in real time on the air time management cycle in the wireless LAN network. Next, the uplink air time and the uplink critical time are compared with each other in real time.

In this case, if the wireless LAN AP has a plurality of SSIDs, the uplink air time may be individually monitored in real time for each of the plurality of SSIDs. Accordingly, the uplink air time and the uplink air time And compare the threshold times.

Steps S140 and S150: When the uplink air time, which is monitored in real time, identifies an uplink superheat event exceeding the uplink threshold time, the wireless LAN environment parameter is changed by setting and broadcasting it so as to mitigate it.

At this time, if the wireless LAN AP has a plurality of SSIDs, the uplink air time monitored in real time for each SSID is configured to identify an overheating event for each uplink SSID exceeding a threshold time for each uplink SSID corresponding to the corresponding SSID. Accordingly, the wireless LAN environment parameter is changed and set in correspondence with the uplink overheating event (hereinafter, referred to as 'overheating event per uplink SSID') identified by the SSID.

Here, the WLAN environment parameter is preferably configured to include at least one of an ECW parameter value and an AIFSN parameter value. When an uplink overheating event is identified in the WLAN network, one or more of the ECW parameter value and the AIFSN parameter value is increased and broadcast so as to mitigate it. The results of the WLAN network when the WLAN environment parameters are changed and set are as described above with reference to FIG. It is preferable to restore the wireless LAN environment parameter back to the original value when it is determined that the uplink superheat event has been sufficiently solved according to the preset reference.

FIG. 8 is a flowchart illustrating a process of controlling downlink air time in a wireless LAN network according to the present invention.

Step S210: The second embodiment of the present invention is a method for controlling a downlink air time (T-dl (t)) by a wireless LAN AP in a wireless LAN network to which a wireless LAN AP and one or more stations are connected, , And sets a downlink threshold time (Th-downlink) for a preset air time management period.

On the other hand, when the wireless LAN AP has a plurality of SSIDs, a threshold time (Th-downlink, SSID) for each of the plurality of SSIDs can be set for each downlink SSID within the range of the downlink threshold time.

Steps S220 and S230: The downlink air time is monitored in real time on the air time management cycle in the wireless LAN network, and then the downlink air time and the downlink critical time are compared with each other in real time.

Here, if the wireless LAN AP has a plurality of SSIDs, it is configured to separately monitor the downlink air time individually for each of the plurality of SSIDs. Accordingly, the downlink air time and the critical time- .

Steps S240 and S250: If the downlink air time that is monitored in real time identifies a downlink overheating event that exceeds the downlink threshold time, the downlink data transmission in the corresponding air time management period is stopped.

At this time, if the wireless LAN AP has a plurality of SSIDs, the downlink air time monitored in real time for each SSID is configured to identify the overheating event for each downlink SSID exceeding the threshold time for each downlink SSID corresponding to the corresponding SSID, The downlink data transmission in the corresponding airtime management period of the corresponding SSID is stopped in response to the overheating event for each downlink SSID.

Step S260: After stopping the downlink data transmission within one airtime management period, it can be configured to resume the suspended downlink data transmission in the next airtime management period.

Here, if the wireless LAN AP has a plurality of SSIDs, the downlink data transmission in the corresponding air time management cycle of the corresponding SSID is stopped in response to the overheating event for each downlink SSID, And resume one downlink data transmission.

The present invention can also be embodied in the form of computer readable code on a computer readable recording medium. At this time, the computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored.

Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage, and the like, and may be implemented in the form of a carrier wave . The computer-readable recording medium can also be stored and executed by a computer-readable code in a distributed manner on a networked computer system. And functional programs, codes, and code segments for implementing the present invention can be easily deduced by programmers skilled in the art to which the present invention belongs.

Claims (8)

A method for a wireless LAN AP to control an air time in a wireless LAN network to which a wireless LAN access point and at least one station are connected,
(a) setting an uplink threshold time for a predetermined air time management period;
(b) monitoring the uplink air time in real time for each air time management period in the wireless LAN network;
(c) comparing the uplink air time and the uplink critical time in real time;
(d) identifying an uplink superheat event in which the real-time monitored uplink air time exceeds the uplink threshold time;
(e) changing and setting environment parameters of the WLAN network in response to the uplink overheating event;
Wherein the airtime control method comprises the steps of:
The method according to claim 1,
Separately setting a threshold time for each uplink SSID within the range of the uplink threshold time for each of the plurality of SSIDs in the step (a)
Monitoring separately uplink air time for each of the plurality of SSIDs in step (b)
Comparing the uplink air time monitored in real time for each SSID with the threshold time for each uplink SSID in step (c)
Wherein the uplink air time monitored in real time for each SSID in the step (d) identifies an overheating event for each uplink SSID exceeding a threshold time for each uplink SSID corresponding to the corresponding SSID,
Wherein the environment parameter of the wireless LAN network is changed and set in response to the uplink event for each uplink SSID in step (e).
The method of claim 2,
Wherein the environment parameter includes at least one of an ECW parameter value and an AIFSN parameter value in the step (e).
The method of claim 3,
Wherein at least one of the ECW parameter value and the AIFSN parameter value is incremented and broadcasted in response to the uplink superheat event in step (e).
A method for a wireless LAN AP to control an air time in a wireless LAN network to which a wireless LAN access point and at least one station are connected,
(a) setting a downlink threshold time for a predetermined air time management period;
(b) monitoring in real time the downlink air time for each air time management period in the wireless LAN network;
(c) comparing the downlink air time with the downlink threshold time;
(d) identifying the downlink air time that the real-time monitored downlink air time exceeds the downlink threshold time;
(e) stopping downlink data transmission in the air time management cycle in response to the downlink overheating event;
Wherein the airtime control method comprises the steps of:
The method of claim 5,
Separately setting a threshold time for each downlink SSID within the range of the downlink threshold time for each of the plurality of SSIDs in the step (a)
Monitoring in real time the downlink air time separately for each of the plurality of SSIDs in step (b)
Comparing the downlink air time monitored in real time for each SSID in step (c) with the threshold time for each downlink SSID,
Wherein the downlink air time monitored in real time by the SSID in the step (d) identifies an overheating event for each downlink SSID that exceeds the threshold time for each downlink SSID corresponding to the corresponding SSID,
Wherein the downlink data transmission in the corresponding airtime management cycle of the corresponding SSID is stopped in response to the overheating event for each downlink SSID in the step (e).
The method of claim 5,
After the step (e)
(f) resuming the suspended downlink data transmission in the next airtime management cycle;
And controlling the airtime of the wireless LAN network.
A computer-readable recording medium storing a program for causing a computer to execute a method of controlling an air time in a wireless LAN network according to any one of claims 1 to 7.

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