Lecture Note
p {margin: 0; padding: 0;} .ft00{font-size:18px;font-family:Times New Roman,Bold;color:#000000;} .ft01{font-size:18px;font-family:Times New Roman;color:#000000;} .ft02{font-size:18px;font-family:Cambria Math;color:#000000;} .ft03{font-size:16px;font-family:Cambria Math;color:#000000;} .ft04{font-size:12px;font-family:Cambria Math;color:#000000;} .ft05{font-size:16px;font-family:Times New Roman;color:#000000;} .ft06{font-size:14px;font-family:Cambria Math;color:#000000;} .ft07{font-size:21px;font-family:Times New Roman;color:#000000;} .ft08{font-size:21px;font-family:Cambria Math;color:#000000;} .ft09{font-size:16px;font-family:Times New Roman,Bold;color:#000000;} .ft010{font-size:18px;line-height:22px;font-family:Times New Roman;color:#000000;} .ft011{font-size:16px;line-height:23px;font-family:Cambria Math;color:#000000;} .ft012{font-size:21px;line-height:25px;font-family:Cambria Math;color:#000000;} .ft013{font-size:21px;line-height:30px;font-family:Cambria Math;color:#000000;} Expression for bit error rate in wired additive white gaussian noise (AWGN) channel Wired Communication Let x be the transmitted signal in wired communication, where additive white gaussian noise channel is considered, then received signal y is represented as 𝑦 = 𝑥 + 𝑛 Where n is the AWGN signal. In AWGN channel Bit error rate(BER) is expressed as, 𝐵𝐸𝑅 = 12 𝑒𝑟𝑓𝑐 (√ 𝐸 𝑏 𝑛 0 ) = 𝑄(√𝑆𝑁𝑅) Where 𝑒𝑟𝑓𝑐(𝑥) is the complementary error function, 𝐸 𝑏 is the noise signal energy and 𝑛 0 is the variance. This can also represent in terms of probability (Q) function and signal to noise power ratio (SNR), expressed as 𝑆𝑁𝑅 = ( 𝑃 𝜎 2 ) So BER = 𝑄 (√ 𝑃 𝜎 2 ) Where 𝑃 is the signal power and 𝜎 2 is the noise power The equation for probability of error in wired system can be formed by applying Chernoff bound, i.e., 𝑄(𝑥) ≤ 1 2 𝑒 −𝑥 2 So 𝑝𝑟𝑜𝑏𝑎𝑏𝑖𝑙𝑖𝑡𝑦 𝑜𝑓 𝑒𝑟𝑟𝑜𝑟(𝑃𝑒) = 12 𝑒 −𝑆𝑁𝑅 2 Example: Q: Calculate the SNR required to achieve a probability of error of 10 −6 in a wired AWGN system. Solution: We know that for the expression for probability of error in a wired AWGN system is 𝑃 𝑒 = 12 𝑒 −𝑆𝑁𝑅 2 Here 𝑃 𝑒 = 10 −6 , So SNR can be calculated as 𝑆𝑁𝑅 = −2𝑙𝑜𝑔 𝑒 (2 𝑃 𝑒 ) , So SNR can be calculated as SNR = 14.19dB. Conclusion: The system require 14.19dB of SNR to get a bit error rate of 10 −6 .
Bit Error Rate Analysis in Wired AWGN Channel
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