NATIONAL OPEN UNIVERSITY OF NIGERIA,
PLOT 91 CADASTRAL ZONE, NNAMDI AZIKIWE EXPRESSWAY, JABI – ABUJA
FACULTY OF SCIENCES
JULY 2018 EXAMINATIONS
COURSE CODE: CIT 755
COURSE TITLE: WIRELESS COMMUNICATION I [3 Units]
TIME ALLOWED: 3 Hours
INSTRUCTION: Attempt Question 1 (22 marks) and any other four questions each carrying 12 marks
1(a) Differentiate between time selective and frequency selective channel. (4 marks)
1 (b) List five examples of Wireless Communication devices (5 marks)
1 (c) List Advantages and Disadvantages of Wireless Communication (6 marks)
1 (d) Find the number of channels available in FDMA system if a cellular operator is allocated 13.5MHz for each simplex band. Given that total spectrum allocation is 13.5MHz, channel bandwidth is 35 kHz and guard band at the edge of allocated spectrum is 15 kHz. (7 marks)
2 (a) List the advantages of digital modulation techniques (4 marks)
2 (b) Mention the factors that influence the choice of digital modulation (5 marks)
2 (c) Define QPSK (3 marks)
3 (a) Define offset QPSK and π/4 differential QPSK (3 marks)
3 (b) Explain noise and interference limited system (3 marks)
3 (c) Write the full meaning of the following acronyms: (6 marks)
i. UMTS (1 mark)
ii. FC-FDE (1 mark)
iii. WDMA (1 mark)
iv. LP-OFDMA (1 mark)
v. GPRS (1 mark)
vi. ITU-R (1 mark)
4 (a) List eight different types of services available in wireless communication (4 Marks)
4 (b) How are multiple accesses achievable in Orthogonal Frequency Division Multiple Access
(2 marks)
4 (c) Outline six common forms of Carrier Sense Multiple Access (6 Marks)
5 (a) Explain Two Ray Ground Reflection Model (4 marks)
5 (b) Discuss in details about GSM, Servicing frequency, band, Channels (4 marks)
5 (c) Discuss GSM System Architecture (4 marks)
6 (a) Discuss three subsystems that are linked up with Mobile Telephone Switching Office links (6 marks)
6 (b) Explain GSM Frequency Bands (3 marks)
6 (c) Explain the different methods of micro diversity in detail (3 Marks)
You can get the soft copy for this course or the exam summary answers for this course from 08039407882
Exam summary sample below
