ECE 732: Mobile Communication Systems
Prof. B.-P. Paris
Homework 3
Due: September 17, 2008
Suggested Reading: Review - Tse and Viswanath, chapter 2. Preview -
Tse and Viswanath, chapter 3.
Problems
1. Tse and Viswanath: Problem 2.15
2. MATLAB Experiment
(a) Retrieve the MATLAB function SimulateCOSTChannel.m and
analyze it.
(b) In MATLAB, generate a constant input signal of duration one
second (20,000 samples per second) and let it be input to the
the function SimulateCOSTChannel. Choose, the carrier fre-
quency equal to 1 GHz and vary the Doppler shift to simulate
vehicle speeds from 0 km/h to 100 km/h. Plot the absolute
value of the resulting signal for different vehicle speeds.
(c) In Matlab generate a BPSK modulated signal (see e.g. MATLAB function LinearModulation.m
and MATLAB function plot LinearModRect.mfor an exam-
ple how to do this).
Consider 20 bit periods and sample the signal 10 times per bit-
period. Let the BPSK signal be input to SimulateCOSTChannel
and plot the real part of the resulting signal. Vary the bit rate
between 50 Kbit/s and 1 Mbit/s.
(d) Summarize and analyze your findings. Do NOT include any
plots without clearly labeling the plot and accurately describ-
ing how it contributes to your conclusions. Do NOT include
MATLAB code unless it contributes to your observations.
3. Discuss the relevance of the parameters delay spread and maxi-
mum doppler spread. Explain how they capture the characteristics
of a multi-path fading channel and how they will affect transmis-
sion of message bearing signals. What properties do signals have
to possess so that they are essentially immune to the consequences
of
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