QUESTION 2 (20 Marks) Given a set of empirical measurements of Pr/ P in the table below for a cellular system at 900MHz, a log-normal path loss model is to be established to characterize the system based on the MSE criterion. The generic expression for the model is given by PL (dB) = K + 10n log10 (d/do) + I, where do = 1m, K (dB) = 20 log10 72, and x E N(0, o?) captures the shadowing effect. Distance from Transmitter M = P. /P d m m dB da m ma dB da m m3 dB di m m, dB ds m ms dB a) Find the path loss exponent n and the standard deviation of the shadowing a (dB). (10 marks) b) Assume that two identical base stations (BSs) are deployed 300 metres apart. Both BSs keep transmit- ting. A receiver moves from one of the BSs to the other. Derive the position where the terminal starts to have its signal-to-interference ratio (SIR) fall below 7th with the probability 10%. Give your answer in terms of the Q-function or its inverse function Q-1(.) (10 marks)