rekrowteN | Networker

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Wireless SGI

Ever wondered, what is the SGI under Wireless configuration on your home router? Well, it isn’t not only under home routers. GI is guard interval and it is a space between two transferred symbols. It is not a space between packets, but characters. Space between packets is referred to interframe spacing (IFS) and you have few types of those.

Guard interval tries to eliminate interference between two characters. Normally, it is set to 800 ns in 802.11 standard. In 802.11n standard, you can enable short guard interval – SGI. It is half of the time – 400 ns and assures higher theoretical throughput. It may happen that more collisions will occur caused by interference, so in overall, throughput will be lower. Longer SGI decreases throughput, but also decreases chance of interference. If SGI is enabled, 802.11n standard can have 10-11 % higher throughput. Or said in opposite, if you don’t enable this option, your speed is ~10 % lower. So if your n speed is 150 Mbps, without SGI enabled you have ~135 Mbps.

One response to “Wireless SGI

  1. Pingback: rekrowteN | Networker Stats for Year 2013 | rekrowteN | Networker

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