802.11n: A Survival Guide

Chapter 1. Introduction to 802.11n-2009

I feel the need...

...the need for speed!

—Maverick and Goose, Top Gun

802.11n’s appeal can be summed up in one word—speed. In the stone ages of 1 Mbps and 2 Mbps wireless LANs, the most charitable thing that one could say about the technology was that it was faster than DSL. With the benefit of a decade of development, wireless LAN technology is mature and widely viewed as “the way you connect to a network,” just as Ethernet was in the mid-1990s. When I started working, visitors would often ask where the nearest Ethernet port could be found. Today, they ask for a password for the wireless LAN. The speed of 802.11n is a large part of the reason why so many devices don’t even have the option for Ethernet ports any more. Once 802.11n put wireless LANs on the same performance footing as wired LANs, wireless became the obvious choice.

History

802.11n began life in late 2002, and took exactly seven years to produce from start to finish.^[3] As with all IEEE 802 standards, it began as a study group. The High Throughput Study Group was founded to investigate building an 802.11 physical layer that could provide speeds of 100 Mbps, as measured at the Medium Access Control (MAC) layer. An early rule of thumb for wireless LANs is that the throughput at the MAC layer would be half of the transmission speed. In 802.11b, the 11 Mbps transmission speed topped out at 5-6 Mbps of throughput; in 802.11a/g, the 54 Mbps transmission speed resulted in 25-30 Mbps of ...