Edit: Wireless Access Points, not Modems
I read some time ago that overlapping interference is a lot worse so all modems should use either 1, 6, or 11. But I see a lot of modems in my neighbourhood using all the channels from 1-11, causing an overlapping nightmare. Why do modem manufacturers allow overlapping to happen in the first place?
Edit: To clarify my question, some countries allow use of all channels and some don’t. This means some countries’ optimal channels are 1, 5, 9, 13, while other countries’ optimal channels are 1, 6, 11. Whichever the case, in those specific countries, all modems manufactured should be hard limited to use those optimal channels only. But modems can use any channel and cause overlapping interference. I just don’t understand why modems manufacturers allow overlapping to happen in the first place. The manufacturers, of all people, should know that overlapping is worse than same channel interference…
To add a scenario, in a street of houses closely placed, it would be ideal for modems to use 1, 6, 11. So the first house on the street use channel 1, second house over use channel 6, next house over use channel 11, next house use channel 1, and so on. But somewhere in between house channel 1 and 6, someone uses channel 3. This introduces overlapping interference for all the 3 houses that use channels 1, 3, 6. In this case, the modem manufacturer should hard limit the modems to only use 1, 6, 11 to prevent this overlapping to happen in the first place. But they are manufactured to be able to use any channel and cause the overlap to happen. Why? This is what I am most confused about.
In: Technology
Typically co-channel interference is preferable to adjacent Channel interference. With a big exception.
Imagine you’re at a big family reunion. I’m talking massive. Like Great Grandpa got back from the war and had 20 kids between 3 wives. And each of those kids and theirs kept up the tradition. Now what if they lived in a country with an awesome medical system that guaranteed a long life span and everyone showed up to the family reunion.
Now the event planner(cause 804 people goddamn) came up with 3 incredibly long tables. And to keep things organized each table had 1 golden token. Whoever held the golden token could talk 1 thing and could take as long as they needed.
-This is how WiFi routers handle co-channel interference. Any router within range(above -80db signal strength) and on the same channel would recognize each other and pass a token to decide who is talking.
For most it was fine they would get the token and would say rather mundane things like,”pass the salt”. But Great Grandpa that glorious mothertrucker would share his war stories and everyone else would be stuck until he was done or forget what he was talking about.
– So not only do you have a whole lot of people waiting to talk but Grandpa takes extra time when it’s his turn. When you have an apartment complex with everyone on those same channels, everyone ends up waiting. Since 2.4ghz is the oldest standard, you could have computers upto 20 years old trying to use the same channels and they take a long time when it’s their turn.
Now some people get a little impatient and get up and stand between the tables to hold their own conversations. It makes it a little noisier but it speeds up conversation at the main tables and people can catch up.
-This is were adjacent channels are useful. It makes it a little noisier as they’re talking over the other channels but it allows the different routers put more tokens in play. It makes the error correction have to work a little harder but data is passed faster.
Now if too many people get up it descends into chaos and nobody can hear anyone. So your busy body aunty starts going to these little groups and tells them to sit down. Now you figure instead of sitting at the same table as Grandpa you’ll swap tables.
-You’re experiencing bad WiFi because everyone has set custom channels so you call your ISP. The ISP sends out a Tech and they factory reset your router and it defaults back to 1,6, or 11. They tell you next time it gets slow to reboot it again. This forces your router to jump to the least congested of 1,6, or 11.
It’s getting a little late and the bar opens up so all the 20-30 somethings jump over there. There’s a whole lot of small tables and conversations are going smooth.
-5ghz has now come into play. Whole lot more channels and the devices aren’t nearly as old. Less congestion and better bandwidth.
Now an alternative to jumping channels would be what I call the “good neighbor policy”. Every router in an apartment complex cuts their transmission strength to 65%. This way the routers don’t see as many networks and reduces the number that share the token. The problem with this is twofold. 1. Everyone has to be in on this, so all the ISPs and customers on site have to agree to reduce their signal strength. 2. Large apartment buildings have a lot of concrete. Concrete kills WiFi, and if you’re reducing your transmission strength, you’re increasing the likelihood of dead spots in your WiFi.
When it comes to WiFi there’s no winning.
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