Answer the following questions: 1. Analyse how digital convergence affects people's use of network devices? [4 marks] 2. Compare and contrast DSSS and FHSS. Which one is more suitable than the other,...

Answer the following questions:


1. Analyse how digital convergence affects people's use of network devices? [4 marks]


2. Compare and contrast DSSS and FHSS. Which one is more suitable than the other, and for what scenario? [5 marks]


3. Research on the standard 802.15.4 and identify its MAC layer responsibilities. [4 marks]


4. According to the Shannon’s Channel capacity theorem:




Channel capacity C = B*log (1 + S/N), Where B = Bandwidth and S/N = Signal to Noise Ratio.

Answer the following questions with respect to the Channel capacity theorem: [6 marks]

a. When the Bandwidth increases, what happens?

b. When the Signal to Noise Ratio increases, what happens?

c. When the Signal to Noise Ration S/N tends to infinity what happens?

d. When the Bandwidth tends to infinity what happens?


5. Scrutinize the following scenario: [5 marks]

Consider a communications system operating in the 5.9 GHz band. Assuming the free space loss model for signal attenuation, the gain of both transmitting and receiving antenna to be 1 dB, and a noise level of -85 dBm, calculate:

a. The range of communication if the transmission power is 100mW;

b. The transmission power if you wanted a communication range of 3 Km;


6. In the questions below, please provide True or False for the statements; justify your answer with proper argument(s). (No marks for not giving the justification) [6 marks]

a. Data throughput is the same as modulation rate of the signal.

b. Frequency Diversity is achieved by spreading the signal in time by sending multiple copies of the signal at different time instants.

c. Multipath propagation always improves the SNR.