What are pros and cons of b, g and n WiFi standards on the same speeds?

All I need WiFi for is to share a 10 Mbit/s ADSL Internet connection.

The apartment is not very convenient for WiFi signal distribution (there are numerous WiFi networks in the area, many wifi clients, many walls and the area is quite wide (but the signal is still tolerable so don't suggest adding more access points)) and I tend to limit (in the router settings) the WiFi speed with 11 Mbit/s standard rate to add stability by getting rid of connection rate retrains.

Also I have a choice of b, g, n, bg and bgn modes. What is better to choose here in case I neither need speeds higher than those supported by all of them nor extended compatibility (well, extra compatibility won't harm if removing it adds no profit)? I usually disable n or even g but I am not sure I am right - perhaps they have got some stability improvements too (rather than of speed alone), I don't know their internals so I ask:

What are other pros and cons of 802.11b, 802.11g and 802.11n WiFi standards on the same standard rates when using same hardware (supporting all of them)?

Prologue: About 7 years ago, when there were no n, but only a, b and g, I was very impressed with an experience I've got - while modern USB-attached g WiFi NICs could hardly sense any signal (they were able to establish a very bad connection from time to time but only to loose it in a matter of minutes or even seconds) in a distant room separated by thick metalized walls, an old PCMCIA-attached b (or a, I can't remember) card was able to maintain quite stable connection there and even in a more distant room.

Solution 1:

Limiting the data rate won't improve the range.

IEEE 802.11n would not only have a better data rate rate than IEEE 802.11g, it will also have a better range. So even if you only need 10MBps, you may need the range.

From Wikipedia :

Protocol        Frequency   Data Rate           Indoor range
IEEE 802.11b    2.4GHz      1Mbps to 11Mbps     35m(115ft)
IEEE 802.11g    2.4GHz      6Mbps to 54Mbps     38m(125ft)
IEEE 802.11n    2.4GHz      7Mbps to 72Mbps     70m(230ft)
IEEE 802.11n    5.0GHz      15Mbps to 150Mbps   70m(230ft)

There are theoretically no drawbacks of using 802.11n at 2.4 GHz over 802.11g. But you can't compare the performance of two differents Wifi adapters using two differents protocols. In the case of your old experience, maybe your PCMCIA card was simply more powerful than your USB NIC despite the protocol difference, or maybe your access point was deficient (connecting a b client on a b/g WAP may also impacts g clients).

So, if you have 802.11n clients, then you definitely wants to enable 802.11n support on your access point, and if you don't have any b/g clients, then you may even disable the backward b/g support for better performance.

Also note that if your AP supports IEEE_802.11n at 5GHz, it may (or may not) give you better performance/coverage depending on the perturbation you may have on your area. 5GHz is a much less crowded frequency spectrum than 2.4GHz (Wifi, Bluetooth, Phones, wireless remote, etc.); But since it's a much higher frequency it has a much lower range which is counterbalanced by using more powerful transmitters, but it won't behave with obstacles the same way 2.4GHz do, it depends on the kind of obstacles.

Solution 2:

802.11b is crap, both in speed, security and the fact that if it is in use while the other faster protocols are available, it will slow down everyone's access. It doesn't use much in the way of fancy frequency modulation tricks, so bandwidth suffers, but it is more stable, because it is simple.

802.11g is faster, has better security, but it is a little less stable in case of interference. With a good signal, it can get quite fast.

802.11n is more stable, secure, and can use larger pieces of bandwidth (channels), it still works best at 5Ghz, because all 2.4Ghz channels overlap, and it is difficult to find a channel that is truly free, in the 5Ghz world though, there is none of that.