Chapter Questions
What is the current data rate for the IEEE 802.11 wireless LAN protocol? What protocol is used with wireless communications?
What is the WiMax frequency standard for the United States?
Why was OFDM selected for WiMax?
How does WiMax differ from Wi-Fi?
What transmission method does WiMax use on the uplink and downlink, and why do they differ?
In what frequency band does Bluetooth operate?
How many output power classes does Bluetooth have? List the power level and the operating range for each class.
What is a piconet?
What is the purpose of the inquiry procedure in Bluetooth?
What is the purpose of the paging procedure in Bluetooth?
Define the term backscatter.
What are the three parameters that define a radio frequency identification (RFID) system?
Explain how power is provided to a passive RFID tag.
Explain why some RFID tags (inlays) incorporate dual-dipole antennas.
Cite three advantages for using an active RFID tag.
What are the three frequency bands typically used for RFID tags?
Redesign the cellular system in Figure $10-8$ so that only six different channel groups $(A, B, C$, $D, E, F)$ are used instead of the seven shown.
Describe the concepts of frequency reuse and cell splitting.
Design the split-cell system in Figure 10-10 so that the minimum number of channel groups are used.
Describe the sequence of events when a mobile user makes a call to a land-based phone. Include in your description the handoff once the call has been made.
The cellular system in Figure 10-10 requires splitting of the two cells surrounded by other cells. They need to be split into five cells (from the original two). Determine the minimum number of channel sets that can serve the original and new systems.
Describe Rayleigh fading and explain how to minimize its effects.
A cellular system operates at $840 \mathrm{MHz}$. Calculate the Rayleigh fading rate for a mobile user traveling at $40 \mathrm{mi} / \mathrm{h}$ (100 fades per second).
A mobile user is transmitting two steps above minimum power. Calculate its power output. (1.11 W)
Explain the functions of the base station, switch, and the public switched telephone network (PSTN).
What are the two systems that most mobile telephone service providers presently use?
What is the bandwidth for each channel of IS-136?
What modulation method is used by IS-136?
What is the name of the standards group that documented the Gilobal System for Mobile Communications (GSM)?
What modulation method is used by GSM?
How many users are time-multiplexed into a single GSM frequency?
How many users are time-multiplexed into a single IS-136 frequency?
In GSM, what device is used to minimize the effects of multipath interference?
In code-division multiple access (CDMA), what device is used to minimize the effects of multipath interference?
In GSM, what is the function of the frequency control channel (FCCH) control signal?
In CDMA, what Walsh code has a function similar to the FCCH used in GSM?
In CDMA, what is the function of Walsh code 32 ?
In GSM, what control signal has a function similar to Walsh code 32 , used by CDMA?
What is the name of the standards group that registered CDMA?
What is another name for the $2 G$ version of CDMA?
In CDMA, what type of orthogonal code separates mobile users?
In CDMA, what type of orthogonal code identifies base stations?
In CDMA, how is the system performance affected as the number of users increase?
In CDMA where do the base stations get their frequency reference? What is the frequency and typical power level of this signal?
In CDMA what is carrier feed through? What is its specified power level?
In CDMA and GSM what are the three main categories of interference signals?
What equation is used to calculate the frequencies of interference due to mixing products?
Give two examples of unintentional "mixers" that can cause interference problems when located near base stations.
Refer to Figure 10-18 (display photo for Tektronix RSA 3408A).(a) What is the horizontal scale for the upper and lower photos?(b) What is the vertical scale for the upper and lower photos?(c) How far apart in frequency are the three frequency-shift keying (FSK) signals shown in the lower photo?(d) How many data records are included in the lower photo?
Refer to Figure 10-18 (display photo for Tektronix RSA 3408A).(a) What is the horizontal and vertical scale for the lower photo?(b) In the lower photo, what is the maximum deviation from the final frequency?(c) In the lower photo, what is the maximum deviation from the final frequency after a period of $200 \mu$ sec.?
Discuss the key issues of the wireless application protocol (WAP).
What are the five aspects to consider when securing a communication link?
Why is integrity important?
Define "jamming" as it is related to RF communication.
What are the two categories of attacks on a wireless network? Provide a description of each.
Which type of attack, extemal or internal, is the biggest threat and why?
Why is information encrypted?
What is a key or a cipher key?