binary symmetric channel
Quick Summary
This type of channel transmits only two distinct characters, generally interpreted as 0 and 1, hence the designation binary. The probability of correctly receiving either character is the same, namely, p, which accounts for the designation symmetric.
A binary symmetric channel is a model used in information theory to understand communication over a noisy channel. This channel transmits only two distinct characters, typically represented as 0 and 1, which are also known as bits. The term "symmetric" means that the probability of an error is the same whether a 0 or a 1 is transmitted.
The probability of a bit being transmitted correctly is denoted as p, and the probability of an error is therefore 1 - p. Noise is the sum of random signals that interfere with the intended communication signal. Claude Shannon's work in this area demonstrated that error correction requires reserving additional bits for transmission. The effectiveness of a binary symmetric channel can be measured by subtracting the bits needed for error correction from the raw throughput of bits, expressed as a percentage: 100 × (1 - E), where E represents the average number of bits per error correction symbol. If p = 0.5, meaning bits are correct only half the time, the channel's effectiveness is 0 percent, indicating no information is being transmitted.1
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