A company called Customer Giant Pty Ltd wants to interconnect the local area networks (LANs) of its two premises located d=5 km apart in the same city by a microwave link operating at 24 GHz. The two buildings to host the antennas of the microwave link have the same height of hb=250 m above sea level, allowing masts of the same height 5m to be mounted on them for both the receive and transmit antennas. The senior management for Customer Giant Pty Led is considering which of the two options below it should choose with costs and performance as the basis: Option 1: Buy the equipment for the microwave link, commission and manage it in-house. Option 2: Outsource the service outright from another company. The total upfront costs for acquiring and commissioning the microwave link is CB=$100,000 plus the estimated maintenance cost of CM=$6000 per year. The Commonwealth Bank of Australia (CBA) has agreed to offer Customer Giant a loan at the interest rate of i=7.5% per annum. The microwave equipment has an average lifetime of n=20 years and thereafter can be salvaged for RS=$8000. As Customer Giant Pty Ltd does not have an employee to operate the microwave link it would have to pay a technician to do so at a fee of CO=$120 per day. The second choice is to allow another company to install and run the microwave link so that Customer Giant Pty Ltd pays CSL=$300 per day altogether to use the service without any hidden running costs. a. Assume that cost is the deciding factor, as the performance of the link does not depend on the option chosen. Which of the two techno-economic options is the best and why? Explain. [15 marks] b. Customer Giant Pty Ltd finally made a choice and got the microwave link running between its two offices. Unfortunately, eight months after system commissioning a Ho=260m tall tower was built in the path of the microwave link 2 km away from one of the two offices of Customer Giant Pty Ltd being interconnected by the link. We want to find out whether or not the obstacle will degrade the system's performance, and, if it will degrade performance, by how much. Therefore, this problem has to be diagnosed and fixed professionally. Assume that the Earth bulge in the path of the microwave link is negligibly small. [7 + 8= 15 marks] i. In which Fresnel zone does the topmost part of the obstruction lie? ii. Does the tip of the obstruction cause the diffracted signal to interfere with the direct LOS signal destructively or constructively? Use detailed calculations to explain your