18-06-2012, 11:28 AM
Wi-Fi Technology Note WF104
[attachment=24673]
Overview
The IEEE 802.11n standard was conceived with the goal of increasing wireless local area
network (WLAN) data throughput to a theoretical level of 540Mbps, or 10 times the speed
of 802.11g. Built on OFDM technology used in the 802.11g standard, 802.11n achieves its
higher throughput, in part, by increasing channel spectrum from 20MHz to 40MHz.
In addition to increasing channel utilization through MAC aggregation techniques, 802.11n
also incorporates multiple antennas using a scheme called multiple-input multiple-output
antenna technology, or MIMO. MIMO provides spatial diversity and spatial multiplexing for
increased range and throughput, respectively. A summary of the IEEE 802.11 standard
features is shown in the table below.
Note WF104
Additionally, 802.11n uses OFDM modulation, while 802.11b does not. This means that if
OFDM clients want to communicate in the presence of 802.11b clients, they must use the
slower and less-efficient 802.11b protocol to protect any higher-rate OFDM transmissions.
Failure to do so will affect both 802.11b signaling and 802.11n throughput. Pre-standard
802.11n-based devices now on the market, most of which are consumer products, have
been confirmed to cause interference with 802.11b/g devices.
Summary
Depending on the application and available budget, IT managers may consider many
different 802.11n deployment options: use 802.11n only in high capacity areas such as
lecture halls; deploy only in new network additions or structures; phased deployment, one
building at a time; deployment only in green field application; or some other alternative.
Regardless of the preferred deployment option, Meru offers the only WLAN solution that
co-exists with 802.11n, and IT managers can field an enterprise-grade Meru network today
with the assurance that it will support a wide variety of 802.
[attachment=24673]
Overview
The IEEE 802.11n standard was conceived with the goal of increasing wireless local area
network (WLAN) data throughput to a theoretical level of 540Mbps, or 10 times the speed
of 802.11g. Built on OFDM technology used in the 802.11g standard, 802.11n achieves its
higher throughput, in part, by increasing channel spectrum from 20MHz to 40MHz.
In addition to increasing channel utilization through MAC aggregation techniques, 802.11n
also incorporates multiple antennas using a scheme called multiple-input multiple-output
antenna technology, or MIMO. MIMO provides spatial diversity and spatial multiplexing for
increased range and throughput, respectively. A summary of the IEEE 802.11 standard
features is shown in the table below.
Note WF104
Additionally, 802.11n uses OFDM modulation, while 802.11b does not. This means that if
OFDM clients want to communicate in the presence of 802.11b clients, they must use the
slower and less-efficient 802.11b protocol to protect any higher-rate OFDM transmissions.
Failure to do so will affect both 802.11b signaling and 802.11n throughput. Pre-standard
802.11n-based devices now on the market, most of which are consumer products, have
been confirmed to cause interference with 802.11b/g devices.
Summary
Depending on the application and available budget, IT managers may consider many
different 802.11n deployment options: use 802.11n only in high capacity areas such as
lecture halls; deploy only in new network additions or structures; phased deployment, one
building at a time; deployment only in green field application; or some other alternative.
Regardless of the preferred deployment option, Meru offers the only WLAN solution that
co-exists with 802.11n, and IT managers can field an enterprise-grade Meru network today
with the assurance that it will support a wide variety of 802.