Increasing Data Transmission

As 802.11 evolved, rates of data transmissions increased to 11 Mbps
early in the process of ratifying the specification. The 11-Mbps PHY
layer uses complementary code keying (CCK). This standard is based on
DSSS and offers speeds up to 11 Mbps. However, as distance increases between the wireless user and the access point (or if
there is interference) the rates fall back to various ranges including:


1 Mbps (best)

5.5 Mbps (very good)

2 Mbps (good)

1 Mbps (fair)

0 Mbps (out of range)

Because standardized wireless devices all adhere to the 802.11 standard,
all data rate ranges can be supported, even slower, legacy DSSS
systems. In contrast, when dealing with wired Ethernets, higher speeds
are necessary to keep up the pace with broadband applications that
require increased bandwidth for such items as shown in Figure 10.4:


Streaming video and audio

Internet telephony (VoIP)

Multimedia applications

Installing network-based applications

Faster peak rates permit more nodes to connect efficiently to your
WLAN through one channel. In addition, vendors are proceeding with new 802.11a applications that have speed increasing from 11 Mbps to as
fast as 54-Mbps in the 5-GHz band.