LANCOM 1811n Wireless – LANCOM 1821n Wireless
Chapter 1: Introduction
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EN
technical developments that promise up to six-times the performance in wire-
less LANs.
Some of the improvements refer to the physical layer (PHY), which describes
the transmission of individual bits over the physical medium—in this case the
air represents the physical medium. Other additions are concerned with the
MAC (medium access control) that among other things governs access to the
transmission medium. The two areas are treated separately below.
You can find additional information on this subject in the LCOS refe-
rence manual or in the technical papers relating to this topic.
1.2.1
Advantages of 802.11n
The new technology includes the following advantages:
Higher effective data throughput
The 802.11n standard includes a number of new mechanisms to signifi-
cantly increase available bandwidth. Current wireless LAN standards
based on 802.11a/g enable physical data rates (gross data rates) of up to
54 Mbps, which turn out to be approx. 22 Mbps net. Networks based on
802.11n
currently
achieve a gross data throughput of up to 300 Mbps
(in reality approx. 120 to 130 Mbps net) – theoretically the standard defi-
nes up to 600 Mbps with four data streams. For the first time, maximum
speeds exceed the 100 Mbps of cable-based Fast Ethernet networks,
which are currently standard in most workplaces.
Improved and more reliable wireless coverage
The new 802.11n technologies do not just increase date throughput but
bring about improvements in the range and reduce the wireless dead
spots in existing a/b/g installations.
This results in better signal coverage and improved stability for signifi-
cantly better utilization of wireless networks, in particular for users in pro-
fessional environments.
Greater range
Data throughput generally decreases when the distance between receiver
and transmitter increases. The overall improved data throughput allows
wireless LANs based on 802.11n to achieve greater ranges, as a signifi-
cantly stronger wireless signal is received by the Access Point over a given
distance than in 802.11a/b/g networks.
