MAMEWorld Forums - The Loony Bin - Re: Can I tell you how much I hate wireless?

> The entire 802.11 protocol and everyone who was involved in it can go fuck themselves.

Haha I'm one of those people - I was involved in development of 802.11n. There are a lot of issues involved, and a lot of the time I feel like saying all the people who complain about 802.11 can go fuck themselves.

Firstly, the 2.4GHz band is never going to work well unless you live on a ranch. It's far too crowded. There's only enough space in the band for three non-overlapping channels. If you switch on channel bonding or "wide channels" there's only room for one signal at a time. Sure there are 17 channels or whatever, but they all overlap and interfere with each other so you can't use them all at once anyway. If you're on 2.4GHz and you're anywhere near anyone else on 2.4GHz you're going to be backing off for everyone else's transmissions all the time. You'll also cop interference from leaky microwave ovens, baby monitors, certain cordless phones, and whatever else is using the band.

Spectrum is far more plentiful at 5GHz - you actually get about 16 non-overlapping channels. The biggest drawback is it doesn't penetrate brick and concrete anywhere near as well as 2.4GHz. Antenna choice and placement can make a huge difference to where in your house you get usable signal. 5GHz devices play nicer with each other when spectrum gets tight, largely because they have to be able to play nice with pulse doppler radar in the same band. You're also less likely to be interfering with the neighbours because of the limited range (see, range limitations aren't always a bad thing).

802.11n is a mixed blessing. It gets you better range and turns multi-path reception into an asset. But getting you better range means you're going to be interfering with networks that are further away and vice versa. Yes, 802.11n makes congestion worse by virtue of working further away.

The MAC layer is inherently inefficient, and the overhead for sending a frame tends to grow as you increase the sophistication of the air protocol. You need to do a whole bunch of channel sounding and setup to send your data at high rates, and this takes time. Wireless base stations can do all sorts of tricks to buffer up several smaller frames and concatenate them to reduce overhead, but this increases latency.

Wireless repeaters, WDS, etc. all suck up precious air time as well. They have to deal with the overhead, receive and decode the data on the way in, and possibly handle some errors/retransmissions. Then they have to do the same thing on the way out. If you're using wireless repeaters, expect your latency to double and bandwidth to halve.

People want miracles, but it won't happen, because physics, bitches. Air is a shitty shared medium prone to all kinds of interference and propagation issues. Copper will always perform better in no small part because you have a dedicated channel on each twisted pair. Single mode optical fibre will perform even better on very long runs because it's even close to being immune to electromagnetic interference.

So yeah, if you want wireless, be prepared to deal with physics. Otherwise, you might want to have a chat with God about how the universe should actually work, or you can just go fuck yourself. Or if you think we're all that stupid, go and design a standard with better compromises, get world-wide regulatory approval, and convince people to make interoperable implementations.

More seriously, I get that it's shit compared to wired connections, but can you say with a straight face that the improvements in wireless networking in the last three decades are anything less than spectacular? I mean do you even remember what things were like in the early '90s? We've come a very long way.