Posted: Fri Jun 23, 2006 19:44 Post subject: Lower Speed == Stronger Link??
Here's a question for you...
I've played a bit with the 802.11b PHY, and know that at the different link speeds i.e. 11/5.5/2/1, different modulation schemes are used. Because of this, by going from 11mbps down to 2mbps, you can get away with a weaker signal and still have a reliable connection.
Does the same hold true for 802.11g? I'm having some link reliability troubles. My setup is one WRT54G v3 running DD-WRT connected to my cable modem, providing access for 1 PC. Since the cable modem internet connection maxes out at 8mbps if I'm lucky, will I:
1) lose any performance by lowering the link speed to 11mbps (from 54mbps)?
2) gain any reliability by doing the same?
With the speed set to auto, it rarely drops below 24mbps, even though the link can drop off.
Joined: 23 Jun 2006 Posts: 1 Location: Ottawa, Canada
Posted: Fri Jun 23, 2006 23:00 Post subject:
I am a new member of forum and this is my first post.
Yes, simpler modulations work at longer ranges.
54Mbps/64QAM modulation will require many many times the signal-to-noise ratio of 6Mbps/BPSK modulation to decode properly. Every 3dB difference doubles the range, so 6Mbps signal may be decoded much farther away than 54Mbps signal.
Also, most 802.11b/g radios have more sensitivity and transmit power in 802.11b modes. However, 802.11g mode gives higher throughput and some multi-path resistance.
That's more or less what I expected... I think I'll try running in B mode at 11Mbps, since as I said as long as the wireless link is faster than the cable modem, it shouldn't be the bottleneck.