Bit 3107 Wireless Networks Technologies Question Paper
Bit 3107 Wireless Networks Technologies
Course:Bachelor Of Science In Information Technology
Institution: Kca University question papers
Exam Year:2014
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UNIVERSITY EXAMINATIONS: 2013/2014 ORDINARY EXAMINATION FOR THE BACHELOR OF SCIENCE IN INFORMATION TECHNOLOGY
BIT 3107 WIRELESS NETWORKS TECHNOLOGIES
DATE: APRIL, 2014 TIME: 2 HOURS INSTRUCTIONS: Answer Question ONE and any other TWO QUESTION ONE
(a) Discuss why wireless LANs (WLANs) have become so popular. (6 Marks)
(b) Portable communications have become an expectation in many countries around the world. You can see portability and mobility in everything from cordless keyboards and headsets, to satellite phones and global positioning systems (GPS). The mix of wireless technologies in different types of networks allows workers to be mobile. In this regard, state the standards, speed and applications for LAN and WAN wireless technologies. (6 Marks)
LAN
WAN
Standards
Speed
Applications
(c) The transmission of radio waves is influenced by three major factors. Describe these factors. (6 Marks)
(d) With the aid of a diagram illustrate the three non-overlapping channels that are available within 802.11b and 802.11g standards and explain why this is necessary (5 Marks)
(e) Define the following terminologies in relation to satellite communications:
i. Earth Stations (1 Mark)
ii. Uplink (1 Mark)
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iii. Downlink (1 Mark)
iv. Transponder (1 Mark)
v. Elevation angle (1 Mark)
(f) Differentiate between synchronous transmission and asynchronous transmission. (2 Marks)
QUESTION TWO
(a) Sketch a diagram showing the basic architecture of a 2G mobile phone network, giving the function of at least four components of the network. (9 Marks)
(b) Mobile phone networks use the concept of “frequency re-use” in deployment of their services.
i. Define frequency re-use and give one fundamental requirement that should
govern frequency re-use. (4 Marks)
ii. Determine the portion of the frequency band that can be used in one cell in a
4-cell reuse pattern and 7-cell reuse pattern, assuming a 25 MHz band allocated to the operator. (2 Marks) (c) State five benefits of the GSM technology. (5 Marks)
QUESTION THREE
(a) With the aid of diagrams, explain how satellites operate. (6 Marks)
(b) State two advantages and two disadvantages of the GEO satellite orbit. (4 Marks)
(c) State three satellite link performance factors. (3 Marks)
(d) What are the factors affecting the minimum elevation angle of a satellite earth stations antenna (>0o)? (3 Marks)
(e) i. Differentiate between Fixed-assignment multiple access(FAMA) and Demand-
assignment multiple access (DAMA) (2 Marks) ii. Describe a typical GEO satellite frequency allocation (2 Marks) QUESTION FOUR
(a) State any four features of Bluetooth network. (4 Marks)
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(b) Much like a traditional wired LAN, a WLAN is a grouping of computers and peripheral devices that share a common communications backbone. As is implied by the name, a WLAN allows users to connect to the LAN wirelessly via radio transmission. Describe any three most common components of a WLAN.
(6 Marks)
(c) Those unfamiliar with wireless technology commonly confuse 802.11b and Bluetooth technologies. Both technologies use the 2.4 GHz radio frequency for wireless communications; however, the goal, focus, and concept of Bluetooth is different from 802.11b wireless networking. Discuss. (6 Marks)
(d) Explain briefly four major criteria that a data communication network must meet. (4 Marks)
QUESTION FIVE
(a) PCM (Pulse Code Modulation) is the process in which a signal is sampled, and the magnitude of the each sample with respect to a fixed reference is quantized and converted by coding to a digital signal.
i. Define sampling, quantization and encoding. (3 Marks)
ii. State Nyquist Sampling Theorem (2 Marks)
iii. Voice has frequency ranging from (approximately) 0 to 4000 Hz. To
reconstruct the signal when digitized, at what rate should samples be taken? (2 Marks)
(b) Two enterprise-level encryption mechanisms specified by 802.11i are certified as WPA and WPA2 by the Wi-Fi Alliance: Temporal Key Integrity Protocol (TKIP) and Advanced Encryption Standard (AES). Discuss how these enhance security. (7 Marks)
(c) Explain briefly three features of
i. Circuit switching. (3 Marks)
ii. Packet switching (3 Marks)
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