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How to optimize your Wi-Fi network

Updated on May 14, 2015

Wi-Fi is gradually gaining the momentum to provide the indoor network coverage for especially high data bandwidth requirements.

The prime factor which is affecting the quality of its services is the interference since it is operated in the unlicensed frequency spectrum. So let us see how to reduce the interference to optimize Wi-Fi network to improve its quality of services.

2.4GHz Wi-Fi network:

802.11b/g/n standards are working in 2.4 GHz band.

802.11 b Wi-Fi channels:


Channel number
Start frequency(MHz)
Center frequency(MHz)
End frequency(MHz)
1
2401
2412
2423
2
2406
2417
2428
3
2411
2422
2433
4
2416
2427
2438
5
2421
2432
2443
6
2426
2437
2448
7
2431
2442
2453
8
2436
2447
2458
9
2441
2452
2463
10
2446
2457
2468
11
2451
2462
2473
12
2456
2467
2478
13
2461
2472
2483
14*
2473
2484
2495

Channel bandwidth is 22 MHz

Channel spacing is 5MHz

*- 12 MHz channel spacing for channel 14 only.

802.11g/n channels:

Channel number
Start frequency(MHz)
Center frequency(MHz)
End frequency(MHz)
1
2402
2412
2422
2
2407
2417
2427
3
2412
2422
2432
4
2417
2427
2437
5
2422
2432
2442
6
2427
2437
2447
7
2432
2442
2452
8
2437
2447
2457
9
2442
2452
2462
10
2447
2457
2467
11
2452
2462
2472
12
2457
2467
2477
13
2462
2472
2482
14*
2474
2484
2494

Channel bandwidth is 20 MHz

Channel spacing is 5MHz

*- 12 MHz channel spacing for channel 14 only.

(Not all frequency channels are available for use in all countries)

Non-overlapping channels patterns:

1 – 6 – 11 – 14

2 – 7 – 12

3 – 8 – 13

4 – 9 – 14

5 – 10 – 14

It is always recommended to have channel clearance to avoid co-channel interference.

2.4 GHz Wi-Fi network optimization:

After Wi-Fi network (router/access point) is setup, you can go for optimization. This optimization can be done periodically /whenever you feel the network performance is poor which requires improving the quality of service.

Optimization procedures:

1. Ensure that your Wi-Fi router is working in an environment which is free from other wireless electronic devices that are working in the same frequency band. Also, make sure that the backhaul bandwidth of your Wi-Fi router is working fine and sufficient for your data requirements.

2. Switch off your Wi-Fi router. Scan all the frequency channels (You can use any Wi-Fi frequency spectrum analyzer tool/Free application tools will also be sufficient) & obtain the result.

Let us have some better understanding of choosing the right channel with the following examples.

Example-1

SSID
Channel /Frequency
RSSI(Received Signal Strength Indicator)/RX level(dbm)
A
1
-50
B
6
-70
C
6
-86
D
34
-65

In this example, it is very explicit that the best channel will be channel 11 or channel 14 since both these channels are the only channels that are having non-overlapping pattern with the existing radiating channels.

Example-2

SSID
Channel /Frequency
RSSI(Received Signal Strength Indicator)/RX level(dbm)
A
1
-50
B
6
-60
C
4
-60
D
6
-70
E
1
-65
F
11
-85
G
11
-75
H
7
-70

In this example, the best channel for your Wi-Fi router will be channel 14 only. But channel 14 is not available for use in all countries. In case you are residing in a country where channel 14 is forbidden, then you need to choose another channel. Among all the channels, receive level of channel 11 is less in comparison with other channels.

Rx level of SSIDs: A> B&C>E>D&H >G>F

Channels : 1 > 6 &4 > 1> 6 & 7 > 11 >11

Then channel 13 will be the right option. If channel 13 is chosen, it will have overlapping channel interference from channel 11 only.(channel 12 may also seem to be good option, but it is not having any channel clearance from channel 11)

In some countries, only 11 channels (frequencies) are allowed to operate. In that case, choosing the best frequency will be somewhat complex. The left out channels are: 2, 3,5,8,9 & 10.

Choosing channel 2 will have overlapping channel interference from channels 1 & 6

Choosing channel 3 will have overlapping channel interference from channels 1, 4, 6&7

Choosing channel 5 will have overlapping channel interference from channels 1, 4, 6&7

Choosing channel 8 will have overlapping channel interference from channels 6, 7&11

Choosing channel 9 will have overlapping channel interference from channels 6, 7&11

Choosing channel10 will have overlapping channel interference from channels 6, 7&11

So the option will be channel 2.

Special Case:

Consider the scenario where the result is having 7 numbers of SSIDs only. That is to say no SSID H available. Then the left out channels are: 2, 3, 5,7,8,9 & 10.

Choosing channel 2 will have overlapping channel interference from channels 1 & 6

Choosing channel 3 will have overlapping channel interference from channels 1, 4&6

Choosing channel 5 will have overlapping channel interference from channels 1, 4&6

Choosing channel 7 will have overlapping channel interference from channels 4, 6 & 11

Choosing channel 8 will have overlapping channel interference from channels 4, 6&11

Choosing channel 9 will have overlapping channel interference from channels 6&11

Choosing channel 10 will have overlapping channel interference from channels 6&11

Here we are stuck with 3 channels (frequencies) which are having interference from the least and equal number of overlapping channels. That are channel 2, channel 9 and channel 10.

Under these conditions, the following criteria may be used.

  1. Channel clearance
  2. Rx level of the existing radiating channels.

OPTION-I(CHANNEL 2)

Channel 2 is having a clearance of three channels from channel 6 & zero channel clearance from channel 1.

OPTION-II(channel 9)

Channel 9 is having a clearance of two channels from channel 6 & one channel clearance from channel 11.

OPTION-III(channel 10)

Channel 10 is having a clearance of three channels from channel 6 & zero channel clearance from channel11.

Highest RX level of channel 1: -50 dbm

Highest RX level of channel 11: -75 dbm

So the interference impact of channel 1 on channel 2 will be more than the interference impact of channel 11 on channel 10.Hence, we can omit the OPTION-I. Among OPTION-II and OPTION-III, you are free to choose any one, but it is prudent to choose OPTION-II (channel 9 is having the channel clearance from both the existing radiating channels whereas channel 10 is not having any channel clearance from channel 11)

Briefly the following procedures may be followed for optimizing your Wi-Fi network.

  1. At best, try to choose the non-overlapping channel for your router.
  2. No non-overlapping channel is found, then find a channel which is having interference from the least number of overlapping channels/If you get into a situation where the optional channels are having interference from equal number of overlapping channels, then the following criteria may be used for finding the channel

(i) Channel clearance

(ii) RX level of the existing radiating channels(refer the special case under the example-2)

3.If your router is crowded with more number of Wi-Fi channels, then try to relocate the router to another place in order to mitigate the interference at least from some channels so that you can find a better channel.

4.Still, more interference is existing in your area/Not satisfied with the performance, then it is better to switch over to 5GHz Wi-Fi network.

5GHz Wi-Fi network:

802.11a, 802.11n and 802.11ac standards are working in 5GHz frequency band.

5GHz Wi-Fi channels

Channel Number
Center frequency (MHz)
Channel width (MHz)
36
5180
20
40
5200
20
44
5220
20
48
5240
20
52
5260
20
56
5280
20
60
5300
20
64
5320
20
100
550
20
104
5520
20
108
5540
20
112
5560
20
116
5580
20
120
5600
20
124
5620
20
128
5640
20
132
5660
20
136
5680
20
140
5700
20
149
5745
20
153
5765
20
157
5785
20
161
5805
20
165
5825
20

Channel width 20 MHz/40 MHz (optional)

All channels are non-overlapping.

(Not all channels are available for use in all countries)

All advanced Wi-Fi routers (802.11n & 802.11ac) are equipped with DFS (Dynamic Frequency Selection)-whenever the router finds any interference in its operating frequency, it will automatically switch over to the best available frequency itself. So it doesn’t require any external RF optimization work, but the only drawback is its penetration level will be 30-40 % poor in comparison with 2.4 GHz band due to its higher operating frequency(path loss will be more than that of 2.4 GHz band)

If your router doesn’t have this DFS facility/if you want to do it manually, then the procedures is as follows

  1. Ensure that the backhaul bandwidth of the router is working fine and sufficient for your data requirements.
  2. Switch off your router. Scan all the frequency channels and obtain the result.

Unlike 2.4 GHz Wi-Fi band, all the channels of 5GHz are non-overlapping and hence you are free to choose any channel other than the existing radiating channels.But it is better to choose a channel which is having at least a clearance of one channel from the existing radiating channels in order to avoid the adjacent channel interference .

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    • Dressage Husband profile image

      Stephen J Parkin 2 years ago from Pine Grove, Nova Scotia, Canada

      I have no issues since we are over a quarter of a mile from the nearest neighbor. However this will help anyone in an area where interference is an issue.