QPSK Symbol Error Rate

Problem

Return the symbol error probability of Gray-coded QPSK at the given symbol signal-to-noise ratio:

SER = 2 * Q(sqrt(snr)) - Q(sqrt(snr))^2

where Q is the Gaussian Q-function.

Hint

A QPSK symbol is correct only when both of its quadrature decisions are correct.

case 1

in: [0]

expected: 0.75

case 2

in: [1]

expected: 0.2921390182628589

case 3

in: [4]

expected: 0.044982695392698835

case 4

in: [10]

expected: 0.0015647896369452086

Starter codePython

import math
def qpsk_ser(snr):
    # Your code here
    pass

4 test cases · run your code against them in the editor