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NB1300Plus4 Wireless ADSL Modem Page 39
Wireless
Transmitting Radio Signals
WLAN devices use electromagnetic waves within a broad, unlicensed range of the radio
spectrum to transmit and receive radio signals. When a wireless access point is present, it
becomes a base for other WLAN devices in its broadcast range. WLAN nodes transmit digital
data using FM (frequency modulation) radio signals. WLAN devices generate a carrier wave and
modulate this signal using various techniques. In this way, digital data can then be superimposed
onto the carrier signal. This radio signal carries data to WLAN devices within range of the
transmitting device. The antennae of WLAN devices listen for and receive the signal, which in
turn is then altered and the transmitted data extracted and sent to your computer.
Range
Range should not be a problem in most homes or small offices. If you experience low or no
signal strength in some areas, consider positioning the device in a location between the WLAN
devices maintaining a roughly equal straight-line distance to all devices that need to access the
Router through the wireless interface. Adding more 802.11b/g Wireless Network Adapters to
rooms where the signal is weak can improve signal strength.
Wireless LAN Modes
Wireless LANs can be configured in one of two ways:
Ad-hoc Networking Also known as a peer-to-peer network, an ad-hoc
network is one that allows all workstations and
computers in the network to act as servers to all
other users on the network. Users on the network
can share files, print to a shared printer, and access
the Internet with a shared modem. However, with ad-
hoc networking, users can only communicate with
other wireless LAN computers that are in the
wireless LAN workgroup, and are within range.
Infrastructure Networking Infrastructure networking differs from ad-hoc
networking in that it includes an access point. Unlike
the ad-hoc structure where users on the LAN
contend the shared bandwidth, on an infrastructure
network the access point can manage the bandwidth
to maximize bandwidth utilization.
Additionally, the access point enables users on a wireless LAN to access an existing wired
network, allowing wireless users to take advantage of the wired networks resources, such as
Internet, email, file transfer, and printer sharing.
Infrastructure networking has the following advantages over ad-hoc networking:
■ Extended range: each wireless LAN computer within the range of the access point can
communicate with other wireless LAN computers within range of the access point.