Noise variance can be increased by a factor of 2 4

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Unformatted text preview: noise variance σ 2 be increased without exceeding the original BER? Noise variance can be increased by a factor of : 2. [4 points]: If V is kept the same as originally, but M is increased to 4, by what maximum factor can the noise variance σ 2 be increased without increasing the original BER? Explain your answer! Noise variance can be increased by a factor of : 6.02 Fall 2012, Quiz 2 Page 3 of 17 Suppose the transmitter now converts to on-off signaling, perhaps to save on the average power transmitted, and thereby extend its battery life. Some indication of the average power at the transmitter can be obtained by computing the average value that (y [n])2 would have across all the received good samples in the absence of noise. By this measure it follows that, for a given V , on-off signaling uses half the average power at the transmitter as bipolar signaling, when “0” and “1” are equally likely. You can assume the receiver is properly converted for optimal (i.e, minimum BER) detection of on-off signaling by now using a threshol...
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