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In January 2004 IEEE announced that it had formed a new 802.11 TaskGroup (TGn) to develop a new amendment to the 802.11 standard for local-area wireless networks. The real data throughput is estimated to reach a theoretical 540 Mbit/s and should be up to 40 times faster than 802.11b, and near 10 times faster than 802.11a or 802.11g.
There were two competing proposals of the 802.11n standard: WWiSE ( W orld- Wi de S pectrum E fficiency), backed by companies including Broadcom , and TGn Sync backed by Intel and Philips .
802.11n builds upon previous 802.11 standards by adding MIMO (multiple-input multiple-output) and orthogonal frequency-division multiplexing (OFDM). MIMO uses multiple transmitter and receiver antennas to allow for increased data throughput through spatial multiplexing and increased range by exploiting the spatial diversity.
The Enhanced Wireless Consortium (EWC) was formed to help accelerate the IEEE 802.11n development process and promote a technology specification for interoperability of next-generation wireless local area networking (WLAN) products
802.11 WLAN Standards 802.11b 802.11a 802.11g 802.11n Standard Approved Sept. 1999 Sept. 1999 June 2003 2006 Available Bandwidth 83.5 MHz 580 MHz 83.5 MHz 83.5/580 MHz Frequency Band of Operation 2.4 GHz 5 GHz 2.4 GHz 2.4/5 GHz Data Rate per Channel 1 – 11 Mbps 6 – 54 Mbps 1 – 54 Mbps 1 – 600 Mbps Modulation Type DSSS, CCK OFDM DSSS, CCK, OFDM DSSS, CCK, OFDM, MIMO
Extends range of existing data rates by transmit and receive beamforming
Spatial-multiplexing MIMO technology
Increases data rates by transmitting parallel data streams
MIMO allows system designers to leverage Moore’s law to deliver higher performance wireless systems
HAR IKRIHNAN. July 11, 2006 Operating Modes The PHY will operate in one of 3 modes Legacy Mode – in this mode packets are transmitted in the legacy 802.11a/g format. Mixed Mode – in this mode packets are transmitted with a preamble compatible with the legacy 802.11a/g. The rest of the packet has a new format . In this mode the receiver shall be able to decode both the Mixed Mode packets and legacy packets.
HAR IKRIHNAN. July 11, 2006 Operating Modes–(cont) Green Field – in this mode high throughput packets are transmitted without a legacy compatible part. This mode is optional. In this mode the receiver shall be able to decode both Green Field mode packets, Mixed Mode packets and legacy format packets.
HAR IKRIHNAN. July 11, 2006 Benefits of 802.11n : 1. Irresistible Performance and Range 2. Compelling Capacity 3. No Network Left Behind
HAR IKRIHNAN. July 11, 2006 Challenges of 802.11n : 1. Enterprise Deployment Challenges 2. New Coverage Patterns 3. Variety of Client Devices 4. Consumer and Small Business Already Moving
Conclusion It ’ s All Good 802.11n will substantially increase the performance and ubiquitous wireless access of laptops, desktops, smart phones and entertainment devices over the next several years. Without cost increase, just like the migration from 802.11 cousin 10 Mbps Ethernet to gigabit Ethernet, 802.11n will first appear in client devices and begin to be pervasively deployed in enterprises, homes and eventually metro networks. While there will be teething problems with this new technology, there is no doubt of its pervasive and inevitable deployment.