KR101055476B1 - Channel setting method in WLAN LAN mode - Google Patents

Abstract

The present invention relates to a channel setting method in a WLAN IBSS mode, the method comprising: (A) a WLAN station collecting a beacon in an IBSS mode environment; (B) searching for the existence of a WLAN station in IBSS mode and having the same SSID as the set SSID; (C) if the corresponding WLAN station exists, accessing the WLAN station in IBSS mode; And (D) if the corresponding WLAN station does not exist, selecting a fixed channel based on the channel state to broadcast a beacon to the selected channel, and selecting the fixed channel according to the channel state, thereby reducing channel interference. have.

Wireless LAN, IBSS Mode, Independent Basic Service Set Mode, Occupancy, Interference Rate

Description

Channel selection method in the IBSS mode of the wireless LAN}

The present invention relates to a channel setting method in a WLAN IBSS mode.

In general, a wireless local area network (WLAN) is a wireless local area network (LAN) as a local area network. Such a wireless LAN network provides various advantages as is known.

For example, there is no need for complicated wiring procedures due to computer repositioning or layout changes, no new construction when opening a new LAN network, and it is also very useful in an environment where a user must work while moving with a laptop. In particular, the local network configuration of the place where the work layout arrangement is changed at any time, such as a department store, can be made very easily.

The wireless LAN is mainly used in the 2.4GHz band, 5.2 / 5.8GHz band and 19GHz band, the 802.11a system represented by 5GHz band and 802.11b represented by 2GHz band is the mainstream.

On the other hand, orthogonal frequency division multiplex (OFDM) is used as a communication method, and in the 2.4 GHz ISM band, there is a side conflict with Bluetooth, and more recently, the weight is placed on the 802.11a side of the 5 GHz band.

In general, a wireless LAN network has an infrastructure mode for performing wireless LAN communication through a wireless LAN access point and an IBSS for directly performing wireless LAN communication between wireless LAN stations without using a wireless LAN access point. There is an Independent Basic Service Set mode.

 In this WLAN IBSS mode, each WLAN station collects beacons from neighboring WLAN access points and WLAN stations, and checks whether the communication mode of the collected beacons and the SSID (Service Set Identifier) are the same as the SSID and SSID. If it is determined that the communication mode and the SSID are identical to each other, it directly accesses the corresponding WLAN station through the IBSS mode.

On the contrary, if the communication mode and the SSID are not identical to each other, the WLAN station sets the IBSS mode through a preset channel and broadcasts a beacon including its own state information.

However, in this manner, the WLAN station always broadcasts the beacon using a fixed channel in the IBSS mode. At this time, if the fixed channel is interrupted by the surrounding channel, the speed is significantly reduced.

The present invention has been made to solve the above problems, it is an object of the present invention to provide a channel setting method to check the channel state in the IBSS mode to set the channel to prevent the speed degradation.

The channel setting method in the WLAN IBSS mode of the present invention for achieving the above objects, (A) when the WLAN station is set in the IBSS mode environment, collecting the beacons through the WLAN channel; (B) the WLAN station searching for the presence of a WLAN station in IBSS mode and having the same SSID as the set SSID with reference to the collected beacons; (C) the WLAN station accessing the WLAN station in the IBSS mode if the WLAN station exists as a result of the search; And (D) if the WLAN station does not exist as a result of the search, broadcasting the beacon on the selected channel by selecting a fixed channel based on the channel state.

Also, in the step (D) of the present invention, (D-1) if the WLAN station does not exist, the WLAN station calculates a channel occupancy with reference to the number of SSIDs and signal levels for each channel. ; (D-2) calculating, by the WLAN station, a channel interference rate using the calculated channel occupancy rate; (D-3) the WLAN station selecting a channel having the smallest calculated channel interference rate as a fixed channel; And (D-4) the WLAN station broadcasting a beacon using the selected fixed channel.

In addition, the channel occupancy calculation of the step (D-1) of the present invention is characterized in that the WLAN station calculates using Equation 1.

(Equation 1)

Where CW is the channel occupancy, n is the number of SSIDs received on that channel, SN is the signal level of each SSID, and W is the weight.

In addition, the calculation of the channel interference rate in the step (D-2) of the present invention is characterized in that the WLAN station calculates using Equations 2 to 4.

(Equation 2)

CS = (CW (m) * 2 + CW (m + 1)) / 3

(Equation 3)

CS = (CW (m) * 2 + CW (m-1)) / 3

(Equation 4)

CS = (CW (m) * 2 + CW (m-1) + CW (m + 1)) / 4

Here, CW is the share of each channel, CS is the channel interference rate, Equation 2 is applied to the case of channel 1, Equation 3 is applied to the case of channel 13, Equation 4 is channel 2 to 12 Applies to case.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to the present invention, since a beacon signal is broadcast by selecting a channel having a low occupancy in consideration of the channel occupancy, it is possible to prevent the speed decrease.

In addition, according to the present invention, a channel having the least interference with a neighboring WLAN device may be used to improve performance. As a result, a data rate may be increased and a Retry Packet may be reduced. Can be.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings. In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components as possible, even if displayed on different drawings have the same number as possible. In addition, in describing the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram of a WLAN network to which a channel setting method is applied in a WLAN IBSS mode according to the present invention.

Referring to FIG. 1, a WLAN network is connected to an upper network such as the Internet 30 and performs an access point (AP) 10 for performing wireless LAN communication with each client, and the WLAN access point ( 10. A plurality of wireless LAN stations (STAs) 20 for performing wireless LAN communication in an intra-structural mode or performing direct wireless LAN communication with each other in an IBSS mode, rather than through a wireless LAN access point 10. )

When the IBSS mode is set by the user, the WLAN station 20 configuring the WLAN network collects beacons from the WLAN station 20 adjacent to the WLAN access point 10 using the WLAN channel. do.

The WLAN station 20 determines whether the collected communication mode of each beacon is the same as the IBSS mode, and whether the SSID and the set SSID of each beacon are the same. If the communication modes are the same and the SSIDs are the same, the IBSS is determined. The wireless LAN station 20 is directly connected through the mode.

In contrast, when the communication modes are not identical to each other or the SSIDs are not identical to each other, the WLAN station 20 selects a channel having the smallest channel occupancy in consideration of the channel occupancy and includes its state information through the selected channel. In order to broadcast a beacon or considering interference effects between adjacent channels, a channel having the least interference between channels is selected to broadcast a beacon including its own state information.

As described above, a process of selecting a channel and broadcasting a beacon through the selected channel will be described in detail below with reference to FIG. 2.

2 is a flowchart illustrating a channel setting method in a WLAN IBSS mode according to a first embodiment of the present invention.

Referring to FIG. 2, when the IBSS mode environment including the IBSS mode and the SSID is set by the user (S100), the WLAN station collects beacons through the WLAN channel (S200).

In general, a user sets an IBSS environment to operate a corresponding WLAN station in an IBSS mode. For this purpose, a user sets an IBSS mode in a WLAN communication mode and sets a predetermined SSID or an arbitrary SSID.

As such, when the IBSS mode is set by the user, the WLAN station collects beacons from the WLAN access point and the WLAN station through the WLAN channel.

Here, the beacon includes communication mode information such as infrastructure mode or IBSS mode, communication channel information in use of 1 to 13 channels, preset SSID information, signal level information, and the like.

Thereafter, the WLAN station determines whether a communication mode included in the collected beacons is an IBSS mode and the presence of a WLAN station having the same SSID as the set SSID in order to search for WLAN stations that can communicate in IBSS mode (S300). ).

This is an IBSS mode, which is the same communication mode, and searches whether there is a WLAN station using the same SSID.

Next, if the corresponding WLAN station is present, that is, the wireless LAN station is connected to the corresponding WLAN station using the same SSID and the same SSID in the IBSS mode, without directly accessing the access point between the corresponding WLAN stations. LAN communication is performed (S400).

On the contrary, if the corresponding WLAN station does not exist, the WLAN station calculates the channel occupancy with reference to the channel and signal level included in the collected beacons (S500) or selects the channel having the smallest channel occupancy as the fixed channel. In addition, the degree of interference (interference rate) between the channels is determined to select a channel having the least inter-channel interference as a fixed channel (S600), and the beacon is broadcast using the selected fixed channel (S700).

In order to calculate the channel occupancy of the WLAN station, Equation 1 below is used.

(Equation 1)

Here, CW is channel occupancy, n is the number of SSIDs received in the corresponding channel, SN is the signal level of each SSID, and W is the weight.

In this regard, Table 1 below shows an example of the occupancy rate calculated when the WLAN station sets the weight to 1 based on the number of SSIDs received per channel and the signal level according to the channel, and FIG. have.

(Table 1)

channel One 2 3 4 5 6 7 8 9 10 11 12 13 SSID Count 4 One 2 One One One 3 2 One 3 2 4 3 signal
level
(dBm) 5,7,20, 100 7 7,50 10 9 9 4,6,20 7,10 20 8,9,10 7,10 6,9,10,
50 7,15,20 Share 132 7 57 10 9 9 30 17 20 27 17 75 42

Referring to Table 1 and FIG. 3 above, a channel having the smallest occupancy is channel 2, and a WLAN station selects channel 2 to broadcast a beacon.

However, in the case of channel 2, the channel occupancy ratios of the peripheral channels 1 and 3 are relatively high, and when the beacon is broadcast using the channel 2, the interference occurs due to the channel 1 and the channel 3.

Therefore, it would be better to determine the degree of inter-channel interference, select the channel with the least inter-channel interference as the fixed channel, and broadcast the beacon using the selected fixed channel.

To this end, the WLAN station selects a channel having the least interference between channels using Equations 2 to 4 below.

(Equation 2)

CS = (CW (m) * 2 + CW (m + 1)) / 3

(Equation 3)

CS = (CW (m) * 2 + CW (m-1)) / 3

(Equation 4)

CS = (CW (m) * 2 + CW (m-1) + CW (m + 1)) / 4

Here, CW is the occupancy rate by channel, CS is the channel interference rate, Equation 2 is applied to the case of channel 1, Equation 3 is applied to the case of channel 13, Equation 4 is channel 2 to 12 Applies to the case.

Table 2 below obtains the channel interference rate for the channel having the characteristics of Table 1 by applying the equations (2) to (4), Figure 4 shows a graph.

(Table 2)

channel One 2 3 4 5 6 7 8 9 10 11 12 13 Share 132 7 57 10 9 9 30 17 20 27 17 75 42 Interference 90 67 32 21.5 9.25 14.25 21.5 21 21 22.7 34 52.2 53

Referring to Table 2 and FIG. 4 above, when channel interference is not considered, channel 2 is selected. However, considering channel interference, the wireless LAN station has the smallest interference rate because channel 5 has the smallest interference rate. Selecting 5 to transmit beacons can prevent channel interference, improving performance.

And, accordingly, the WLAN station can increase the data rate and reduce the carrier packet.

Meanwhile, in this case, the degree of interference is determined by obtaining the difference between adjacent channels, but the present invention is not limited thereto, and the degree of interference may be determined by obtaining the difference between channels adjacent to the adjacent channel, or the degree of interference may be determined by obtaining the difference between several adjacent channels. have.

Although the above has been illustrated and described with respect to the preferred embodiments of the present invention, the present invention is not limited to the above-described specific embodiments, it is common in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

1 is a conceptual diagram of a WLAN network to which a channel setting method is applied in the WLAN IBSS mode of the present invention.

2 is a flowchart illustrating a channel setting method in a WLAN IBSS mode according to a first embodiment of the present invention.

3 is a graph showing an example of occupancy applied to the channel setting method in the WLAN IBSS mode of the present invention.

4 is a graph illustrating an example of an interference rate applied to a channel setting method in the WLAN IBSS mode of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: access point 20: wireless LAN station

30: Internet network

Claims (4)

(A) collecting a beacon through the WLAN channel when the WLAN station is set in the IBSS mode environment; (B) the WLAN station searching for the presence of a WLAN station in IBSS mode and having the same SSID as the set SSID with reference to the collected beacons; (C) the WLAN station accessing the WLAN station in the IBSS mode if the WLAN station exists as a result of the search; And (D) if the WLAN station does not exist, as a result of the search, selecting a fixed channel based on a channel state and broadcasting a beacon on the selected channel; Step (D), (D-1) if the wireless LAN station does not exist as a result of the search, calculating the channel occupancy with reference to the number of SSIDs and signal levels for each channel; (D-2) calculating, by the WLAN station, a channel interference rate using the calculated channel occupancy rate; (D-3) the WLAN station selecting a channel having the smallest calculated channel interference as a fixed channel; And (D-4) The WLAN station is a channel setting method in a WLAN IBSS mode comprising the step of broadcasting a beacon using the selected fixed channel. delete The method according to claim 1, The channel occupancy calculation in the step (D-1) is performed by the WLAN station using Equation 1, wherein the channel setting method in the WLAN IBSS mode. (Equation 1)

Where CW is the channel occupancy, n is the number of SSIDs received on that channel, SN is the signal level of each SSID, and W is the weight. The method according to claim 1, The channel interference rate of the (D-2) step is calculated by the WLAN station using Equations 2 to 4, the channel setting method in the WLAN IBSS mode. (Equation 2) CS = (CW (m) * 2 + CW (m + 1)) / 3 (Equation 3) CS = (CW (m) * 2 + CW (m-1)) / 3 (Equation 4) CS = (CW (m) * 2 + CW (m-1) + CW (m + 1)) / 4 Here, CW is the share of each channel, CS is the channel interference rate, Equation 2 is applied to the case of channel 1, Equation 3 is applied to the case of channel 13, Equation 4 is channel 2 to 12 Applies to case.

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