9.1 A mobile system is to provide 95% successful communication at the fringe of coverage, with location variability 8 dB. What fade margin is required? What is the average availability over the whole cell, assuming a path loss exponent of 4?
9.5 Assuming a shadowing decorrelation distance of 50 m, how long does shadowing take to decorrelate for a mobile travelling travelling at 50 km / h
9.7 Two co-channel base stations produce shadowing with a cross-correlation of 0.5 in a certain region. If the location variability is 8 dB, what is the standard deviation of the carrier-to-interference carrier-to-interference ratio experienced by the mobile?
10.2 If a mobile moves at a speed 50 m s _ 1 towards another mobile, also at speed 50m s _ 1, where the first mobile transmits at a frequency of 900 MHz to the second, what Doppler shift does the second mobile experience?
10.4 In calculating the Rayleigh error performance of BPSK, it was assumed that the fading can be assumed constant over one bit duration. Up to what vehicle speed is this assumption valid for the GSM system, given that the bit rate in G SM is _ 270 270 kbps and the carrier frequency is _ 900 900 MHz?
11.1Determine the RMS delay spread for a two-tap channel with equal mean tap powers and a difference in arrival time of t seconds. Find an expression for the spacing between frequencies at which nulls in the spectrum occur.
11.3 A non-line-of-sight channel is measured to consist of two taps with P1 ¼ _ 10 10 dBW, t1 ¼ 3 _ s and P2 ¼ _ 15 15 dBW, t2 ¼ 5 _ s. s. Find the total excess delay, mean delay and
RMS delay spread. What is the impact of introducing a line-of-sight tap with
P0 ¼ 0 dBW, t0 ¼ 2 _ s?
11.5 Calculate the total excess delay, mean delay and RMS delay spread for a channel whose PDP is specified in the following table.Would this channel be regarded as wideband for Wideband Fast Fading 255
a quaternary data system with a data rate of 20 Mbps? Tap number Relative delay [ns] Average relative power [dB] 100 2 4 _ 2 3 6 _ 4 4 17 _ 8 5 18 _ 10 6 50 _ 6
