Unformatted text preview: CSE 4215 :: Lab 1 Multipath Propagation Issued January 12, 2009; Due January 27, 2012 In this lab, you will explore the features of plane-earth multipath propagation. Assume that the transmitting antenna is located at height hT, the receiving antenna is located at height hR, the antennas are distance d apart, and the signal is a pure sinusoid at carrier frequency fc. Two paths are incident on the receiving antenna: the direct path and the ground-reflected path, where the reflection coefficient R is equal to -1. Prepare a lab report answering all of the following questions. 1. Show that the amplitude of this signal is given by 2 sin(fc(d1-d2)/c), where d1 is the length of the direct path between the two antennas, and d2 is the length of the ground-reflected path. 2. Express d1 and d2 in terms of hT, hR, and d. Explain your expression. 3. Let hT = 10m, hR = 2m, and fc = 1 GHz. Using MATLAB (or the method of your choice), plot the absolute value of the amplitude of the signal with respect to d on a log-log scale, for 1m d 100000m. (Hint: in MATLAB, use the command loglog). 4. For the plot you produced in question 3, you should see several "deep fades". What causes these? At what distance does the last "deep fade" occur, and why is this the last one (before d=)? 5. For the plot you produced in question 3, at what point does the O(1/d) behavior take over? Explain. (Hint: First try plotting y = 1/x on a log-log scale, to see how this expression behaves.) 6. Repeat parts 3, 4, and 5 for various values of fc. Draw a general conclusion about the effect of fc on plane-earth path loss, and explain your conclusion. 7. Returning to fc = 1 GHz, repeat parts 3, 4, and 5 for various values of hT. Draw a general conclusion about the effect of hT on plane-earth path loss, and explain your conclusion. Evaluation: Technical correctness: 40 marks o Correctly answering all the above questions is worth 32/40 o To achieve a score greater than 32/40, you must provide additional results, insights, or analysis beyond the provided questions Quality and clarity of report (including plots): 10 marks o For full marks, writing must be clear, grammatical, and detailed; plots must be clearly labeled and unambiguous. ...
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- Winter '12
- Orders of magnitude, log-log scale