By Topic

Wireless LAN Comes of Age: Understanding the IEEE 802.11n Amendment

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Paul, T. ; Atheros Commun., Santa Clara ; Ogunfunmi, T.

During the initial development of the IEEE 802.11n (11n) amendment for improving the throughput of wireless LANs, a lot of excitement existed surrounding the potential higher throughput (i.e., faster downloads), and increased range (distance) achievable. However, delays in the development of this standard (which began in 2003, and is still in the final draft stages) as well as vendor, customer reluctance to adopt the pre-11n offerings in the marketplace, have generally slowed interest in this next-generation technology. However, there is still much to be excited about. The latest draft of IEEE 802.11n (Draft 3.0) offers the potential of throughputs beyond 200 Mbps, based on physical layer (PHY) data rates up to 600 Mbps. This is achieved through the use of multiple transmit and receive antennas, referred to as MIMO (multiple input, multiple output). Using techniques such as spatial division multiplexing (SDM), transmitter beamforming, and space-time block coding (STBC), MIMO is used to increase dramatically throughput over single antenna systems (by two to four times) or to improve range of reception, depending on the environment. This article offers an exposition on the techniques used in IEEE 802.11n to achieve the above improvements to throughput and range. First, the current generation WLAN devices (11a/b/g) are described in terms of the benefits offered to end users. Next, the evolution of the Tin amendment is discussed, describing the main proposals given, and illustrating reasons for the delay in standardization. Then, the changes to the PHY for 11n are presented. A description of channel modeling with MIMO is shown, followed by the signal processing techniques employed, including MIMO channel estimation and detection, space-time block coding (STBC), and transmitter beamforming. Simulation results are presented which illustrate the benefits of these techniques, versus the existing a/g structures, for both throughput and range. Finally, a brief section outlini- ng considerations for the rapid prototyping of a baseband design based on the 802.11n PHY is presented. We conclude with a discussion of the future for 11n, describing the issues addressed with Drafts 2.0 and 3.0, as well as its place in a wireless market with WiMAX and Bluetooth.

Published in:

Circuits and Systems Magazine, IEEE  (Volume:8 ,  Issue: 1 )