COMPUTER SCIENCE &
Chapter 03. Spread
1. Increasing the dwell time for an FHSS system
will increase the throughput.
A. This statement is always true
B. This statement is always false
C. It depends on the manufacturer of the equipment
2. Which one of the following dwell times will
result in the greatest throughput in a FHSS
system and will still be within FCC regulations?
A. 100 ms
B. 200 ms
C. 300 ms
D. 400 ms
3. An 802.11b compliant wireless LAN
configuration using DSSS can have a maximum
of ___ non-overlapping, co-located access points.
4. Consider the following two wireless LAN configurations:
System 1. IEEE 802.11 compliant FHSS system, 6 colocated access points running at maximum data rate.
System 2. IEEE 802.11b compliant DSSS system, 3 co-
located access points running at 50% of maximum data
Which one of the following statements is true?
A. System 1 will have more throughput
B. System 2 will have more throughput
C. System 1 and System 2 will have the same throughput
5. Channels on direct sequence systems for
802.11b equipment are ___ MHz wide.
6. Which of the following are advantages of
802.11b DSSS over 802.11 FHSS?
Choose all that apply.
D. Resistance to narrowband interference
7. If having compatible equipment from different
manufactures were an important factor when
purchasing wireless LAN equipment, which of
the following spread spectrum technologies would
be the best choice?
8. The FCC has two sets of rules regarding FHSS
that are known as before and after which of the
9. The latest published FCC rules regarding
power output for FHSS states a maximum output
of which one of the following?
A. 100 mW
B. 125 mW
C. 200 mW
D. 1 W
10. The FCC specifies how many channels in the
2.4 GHz ISM band that can be used for DSSS in
the United States?
11. You have been hired on as a consultant to increase the
capacity of an existing wireless LAN based on FHSS
recommend that a replacement system based on DSSS
would be better. Which of the following could be your
arguments to defend your position? Choose all that apply.
A. The DSSS devices will cost less and have more throughput
B. The DSSS devices will cost more but have more throughput
C. Additional new FHSS devices may not be compatible with
the older devices
D. DSSS is more secure than FHSS
12. The statement, “802.11b wireless LAN
devices are backward compatible with 802.11
wireless LAN devices” is:
A. Always true
B. Always false
C. Sometimes true
13. What is considered to be the maximum
number of co-located FHSS access points in a
wireless LAN, if non-synchronized radios are to
14. In Frequency Hopping wireless LAN systems, the
term hopping refers to which one of the following?
A. Switching between throughput speeds from 11 Mbps to
B. What happens when the carrier frequency is changed
C. The change that occurs as a result of the RF signal
D. Changing technologies from FHSS to DSSS
15. A DSSS channel is more susceptible to narrowband
interference than a FHSS channel because of which of the
following? Choose all that apply.
A. The DSSS channel is much smaller (22 MHz wide instead of the 79
MHz wide band used by FHSS)
B. The information is transmitted along the entire band
simultaneously instead of one frequency at a time
C. FHSS systems simply avoid the frequency on which the
narrowband interference is located
D. FHSS systems only use one frequency at a time, so the narrowband
interference must be on the same exact frequency at the same time
16. The noise floor is defined by which one of the
A. The general level of RF noise in the environment
around the wireless LAN
B. The noise that is generated as a result of foot
C. A fixed level of -100 dBm
D. The level of noise at which a wireless LAN starts
17. Which one of the following is not described by
the IEEE and OpenAir standards regarding
A. What frequency bands may be used
B. Hop sequences
C. Allowable levels of interference
D. Dwell times
E. Data rates
18. An RF signal is considered spread spectrum when
which of the following are true?
Choose all that apply.
A. The system sending the signal is using infrared
B. The power required to send the information is
significantly greater than is necessary
C. The bandwidth used is much wider than what is
required to send the information
D. The bandwidth used is much less than what is used to
send the information
19. Some 2.4 GHz FHSS systems operate at 3
Mbps or more. Which of the following is true
regarding these systems?
A. They are always IEEE 802.11 compliant
B. They may not interoperate with other FHSS
C. They are always OpenAir compliant
D. They are backwards compatible with 900 MHz
20. How many different types of implementations
of spread spectrum technology does the FCC
specify for the 2.4 GHz ISM band?