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Appendix A: FAQ about WLAN
1. Can I run an application from a remote computer over the wireless network?
This will depend on whether or not the application is designed to be used over a network. Consult
the application’s user guide to determine whether it supports operation over a network.
2. Can I play computer games with other members of the wireless network?
Yes, as long as the game supports multiple players over a LAN (local area network).
Refer to the game’s user guide for more information.
3. What is Spread Spectrum?
Spread Spectrum technology is a wideband radio frequency technique developed by the military
for use in reliable, secure, mission-critical communications systems. It is designed to trade off
bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is
consumed than in the case of narrowband transmission, but the trade-off produces a signal that is,
in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the
spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a
spread-spectrum signal looks like background noise. There are two main alternatives, Direct
Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).
4. What is DSSS? What is FHSS? And what are their differences?
Frequency-Hopping Spread-Spectrum (FHSS) uses a narrowband carrier that changes frequency
in a pattern that is known to both transmitter and receiver. Properly synchronized, the net effect is
to maintain a single logical channel. To an unintended receiver, FHSS appears to be
short-duration impulse noise. Direct-Sequence Spread-Spectrum (DSSS) generates a redundant
bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The
longer the chip, the greater the probability that the original data can be recovered. Even if one or
more bits in the chip are damaged during transmission, statistical techniques embedded in the
radio can recover the original data without the need for retransmission. To an unintended receiver,
DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband
receivers.