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# Propagation Fundamentals - Cellular Systems

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1. A cell is located over smooth, flat terrain. The system operates in the 1900 MHz band and the base station antenna is located 15 m above the ground. The mobile terminal is 250 m away from the base and its antenna is 1.5 m above the ground. (Use 1920 MHz in your computations.)
(a) Compute the propagation loss.
(b) What is the free space propagation loss? Does it apply here?
(c) Plot the propagation loss from 250 to 400 m. How many dB does it vary by over this range?
(d) Approximately how "smooth" does the terrain have to be for these computations to be valid?

2. In the cell of problem 1, there is one building located 125 m from the base.
(a) Approximately what building height would significantly impact the propagation path between the base and the mobile?
(b) Unfortunately, the building is 12 m high. Estimate the propagation loss.

3. Suppose the cell of problem 1 is located in a suburban environment where the propagation loss coefficient is 4.5. The average propagation loss measured at a variety of locations 100 m from the base is 95 dB.
(a) Estimate the average propagation loss at locations 250 m from the base station.
(b) The standard deviation of the log-normal propagation loss distribution is 9 dB. What propagation loss would you design for to provide approximately 90 percent confidence of an acceptable radio link?