Question 1
Consider a QPSK modulation that achieves a bit error rate of P₆=10-³on the AWGN channel.Find the outage probability of this QPSK modulation for the Rayleigh fading channel with selection combining (SC)diversity for M=1(no diversity), M=2 and M=3.Assume unequal branch SNRs with γ1=10 dB,Y₂=15 dB,and y₁=20 dB.
Hint:Determine the bit error probability formula and evaluate the Q-function using Q-function table or mathematic softwares(e.g.,Matlab or Mathematica).Please be aware that this question assumes unequal branch SNRs,where M=1 contains γ1,but M=2 contains bothy₁and γ2 ·
Question 2
Assume that four branch diversity is used,where each branch receives an independent Rayleigh fading signal.If the average SNR is 20 dB on each branch,determine the probability that the SNR will drop below 10 dB. Compare this with the case of a single receiver without diversity.Consider SC first,then MRC.