One of the most common mistakes many businesses make when first deploying a WLAN is to configure multiple access points all on the same channel as depicted in Figure 4. If all of the APs are on the same channel, unnecessary medium contention overhead occurs.
Wi-Fi uses a listen-before -you-talk technology called the clear channel assessment CCA to ensure that only one radio can transmit on the same channel at any given time. If an AP on channel 1 is transmitting, all nearby access points and clients on the same channel will defer transmissions.
The result is that throughput is adversely affected: Nearby APs and clients have to wait much longer to transmit because they have to take their turn. The unnecessary medium contention overhead that occurs because all the APs are on the same channel is called co-channel interference CCI. In reality, the The unnecessary medium contention overhead caused by co-channel interference is a result of improper channel reuse design.
If only three channels are available for a channel reuse pattern, it is pretty much a given that there will be access points on the same channel within hearing distance of each other.
One of the advantages of using the 5 GHz frequency band is that there are many more channels. In Europe, a 2. Although there is a small amount of frequency overlap between those four channels, the performance might in some cases be better if the medium contention overhead of co-channel cooperation can be reduced because there is less channel bleed over.
I am personally not a big believer of the four-channel plan, even in Europe. The four-channel plan has disadvantages. Also, all North American Wi-Fi radios are restricted by firmware and cannot transmit on channel The IEEE In the United States, the Federal Communications Commission FCC allocates spectrum in both bands for wireless communication and has now expanded that spectrum allocation to include 6 GHz More info to come on that!
The 2. In the 5GHz band, we have channels ranging from 36 up to , and in the 6 GHz band, we have Wi-Fi channels ranging from Both frequencies allow for channel width from 20 MHz MHz. Even though there are 11 channels available in 2. Channels interfere with 1 and 6, while interfere with 6 and Without getting too deep on how wireless communication happens, when a station Access Point, client device, etc.
Put simply, only one device can transmit at a time. When overlapping channels are used , in 2. This essentially turns both cells a cell is the coverage area for an AP into one big cell. This is caused by more devices trying to gain access to the wireless medium on the same channel, making STAs wait longer for their chance to transmit.
Up to this point, we have only used the 2. With its limited amount of available spectrum, it is highly recommended that only non-overlapping 20 MHz channels are used, even though the ability to use 40MHz was introduced in This is where the topic of channel width gets interesting.
One of the main differences between the 2. Because 2. Meanwhile, the higher 5 GHz WiFi frequency supports much faster speeds, allowing you to upload and download files faster for better performance. Now as we've already touched upon, WiFi channels are the smaller bands within each WiFi frequency band. There are 11 WiFi channels in the 2. With that being said, it's important to note that some of these channels cause more WiF interference than others because they overlap.
Each channel on the 2. The channel centers are separated by 5 MHz, and the entire spectrum is only MHz wide. This means the 11 channels have to squeeze into the MHz available, and in the end, overlap. The example MetaGeek uses here is what is called Adjacent-Channel interference— where neighboring WiFi channels overlap with one another.
Other forms of interference also include Co-Channel— where numerous client devices are competing with one another on the same channel— and Non-WiFi— where other common household devices, like microwaves, compete for signal on one of the WiFi frequency bands 2.
With these WiFi frequency band and WiFi channel aspects in mind, you can now find the best WiFi channel for your router. Follow these steps:. And while we're on the topic of finding the best WiFi channel for your router, it's important to note that many routers today are designed to automatically choose which WiFi channel to use.
However, at Minim, we did observe that routers don't always choose the best WiFi channel available and so this shouldn't be trusted entirely.
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