TEST1 REVIEW QUESTIONS (10/22/2010)
1.
2.
3.
4.
5.
6.
7.
8.
9.
What are the differences between wireless and wireline networks
What are the differences between different wireless media
What are the differences between centralized and ad-hoc wireless networks
List different types of cellular wireless network elements and their functions
List differences between soft and hard handoff
What are the SDU functions – select/combine -distribute?
List differences between macro and micro mobility?
Describe procedures and steps (with an example) in micro-mobility management
List four handoff algorithms and explain the benefits and disadvantages of each one of
them
10. What is a ping-pong effect during micro-mobility. How do you avoid this
11. Compare wireless network elements (see the list below for more details) with wire line
network components like access devices, access router, edge router, core router, gateways
Comparison in terms of functions, bandwidth, physical distance and session setup
a. Mobile Station
b. Base Transceiver System
c. Base Station Controller
d. Mobile Switching Center
e. Packet Inter-Working Function
12. What are the differences between wireless and wire line networks in terms of
a. QoS
b. Transmission rates
c. OA & M (Operation, Administration & Maintenance)
d. Security
13. Give examples for bandwidth for
i. BTS-BTS
ii. BTS-BSC
iii. BSC-BSC
iv. BSC-MSC
v. MSC-MSC
14. Different the steps in handoff process between two base stations (describe with an event
flow.
15. We want to provide a cellular communication service to downtown Dallas.
i. Total available spectrum: 100Mhz
ii. Bandwidth needed per user: 30Khz
iii. Frequency reuse factor = 5
Calculate the no. of subscribers you can support if you have 20, 40, 60 BTSes (all the three
cases). Give crisp answers (numerical wherever applicable) to each case. Clearly state any
assumptions
20 BTS
No. of subscribers
40 BTS
60 BTS
16. State two differences between shared memory and pipe
17. Shmget(1024,2048,0644|IPC_CREAT): In this method, what is the size of shared
memory being allocated and what are the permissions being given.
18. Shmat(shmid,(void *)0,SHM_RDONLY): In this method, where shmid is the shared
memory Id. In the given method there are three parameters, what does the second and
third parameters convey? And what is the return value of the given method?
19. What is the method to be used to destroy the shared memory segment? Specify along
with parameters.
20. What do you do if there are any concurrency issues(multiple updates at a time) in shared
memory?
21. What do you mean by blocked read and write in pipes?
22. What are the differences between full duplex and half duplex pipes?
23. State two benefits and limitations of pipes
24. Can we use pipes to establish a communication between two processes on two different
machines? If yes how
25. Name two messages (just name them) used for handoff between BS—BS/MSC and two
messages used for origination and termination of phone calls (MS-BS-MSC)
26. Name two messages (just name them) used for call setup between MS—BS and two
messages used for origination and termination of phone calls (BS-MS)
27. What are the forward and reverse control channels (just list them)
28. What is the approximate size of the RF frame
29. What is the difference between “blank & burst” and “dim and burst” in signaling/control
messages
30. What is a frequency reuse factor ? How do you use it
31. List three kinds of registrations
32. What is the difference between micro and macro mobility
33. What is the difference between soft and hard hand off
34. List and explain two performance parameters during hand off
35. Explain the difference between close loop and open loop power control
36. What are the functional differences between BS-BS hand-off and active-standby (during
failures) BS in the network
37. Draw a diagram of a heterogeneous network that includes PSTN, SS7, Cellular, WiFi,
and VoIP . Clearly specify/discuss the interworking protocols. Draw a call flow between
different domains.
38. What is the specification of QoS in WiFi ?
39. Discuss the differences between Cell-WiFi and Cell-Cell handoff
40. What are the problems in supporting multimedia/TV services over cellular networks
41. What are the QoS targets for voice, data, and video (in terms of packet/frame loss, bit
loss, delay and jitter)
42. How do we fix TCP for tolerating the QoS issues in the cellular network
43. What are the functions of PCF, PDSN.
44. What is the difference between DCF and PCF in WiFi MAC protocol? List a
corresponding application for DCF and PCF
45. List six 10 different mobile applications (distinct) that can use the sensors in the mobile
phone