Assignment:
A radio link sends BPSK signals to a receiver with a bit rate of 100 kbps. It is found that the output of a radio receiver when no signal is present is AWGN with a rms voltage of 1.0 V.
a. What is the usual source of additive white Gaussian noise (AWGN) in a radio receiver?
b. For what percentage of the time is the noise output of the receiver greater than + 2.0 V or more negative than -2.0 V?
c. A 100 kbps BPSK signal is sent to the radio receiver. At the sampling instant at the receiver output the voltage when a logical 1 is sent is +3.0 V and the voltage when a logical zero is sent is -3.0 V. What is the average bit error rate? [Use the Q (z) table below to estimate BER.]
d. What is the average time between errors?
e. The transmitter power is increased so that the sampled voltages at the receiver output are +6.0 V and - 6.0 V. What is the bit rate now and the average time between bit errors?
z Q(z) z Q(z)
0 0.5
2.0 2.280 E-2 5.1 1.701 E-7
2.1 1.791 E-2 5.2 9.981 E-8
2.2 1.394 E-2 5.3 5.799 E-8
2.3 1.075 E-2 5.4 3.372 E-8
2.4 8.220 E-3 5.5 1.902 E-8
2.5 6.227 E-3 5.6 1.073 E-8
2.6 4.674 E-3 5.7 6.000 E-9
2.7 3.476 E-3 5.8 3.320 E-9
2.8 2.562 E-3 5.9 1.820 E-9
2.9 1.871 E-3 6.0 9.979 E-10
3.0 1.354 E-3 6.1 5.310 E-10
3.1 9.702 E-4 6.2 2.827 E-10
3.2 6.889 E-4 6.3 1.490 E-10
3.3 4.847 E-4 6.4 7.778 E-11
3.4 3.378 E-4 6.5 4.021 E-11
3.5 2.332 E-4 6.6 2.058 E-11
3.6 1.595 E-4 6.7 1.043 E-11
3.7 1.081 E-4 6.8 5.236 E-12
3.8 7.252 E-5 6.9 2.603 E-12
3.9 4.821 E-5 7.0 1.281 E-12
4.0 3.174 E-5 7.1 6.244 E-13
4.1 2.070 E-5 7.2 3.014 E-13
4.2 1.337 E-5 7.3 1.440 E-13
4.3 8.558 E-6 7.4 6.816 E-14
4.4 5.423 E-6 7.5 3.194 E-14
4.5 3.404 E-6 7.6 1.482 E-14
4.6 2.117 E-6 7.7 6.810 E-15
4.7 1.303 E-6 7.8 3.098 E-15
4.8 7.948 E-7 7.9 2.396 E-15
4.9 4.800 E-7 8.0 6.226 E-16
5.0 2.872 E-7