Which concept defines the maximum rate at which information can be transmitted over a channel with a given noise level and bandwidth?

Which concept defines the maximum rate at which information can be transmitted over a channel with a given noise level and bandwidth?

• A. The maximum theoretical data rate for reliable communication given the channel noise level
• B. The minimum energy per bit required for reliable reception
• C. The channel dispersion
• D. The Shannon limit

Answer: (D)

The idea here is channel capacity—the highest data rate at which information can be transmitted over a noisy channel without error in the limit of long code blocks. For a channel with bandwidth and a given signal-to-noise ratio, the ultimate limit is the Shannon capacity: C = B log2(1 + S/N). This bound, known as the Shannon limit, says that no matter how clever your modulation and coding, you can’t reliably exceed this rate; below it, there exist coding schemes that can approach error-free transmission as blocklength grows. The other concepts describe different aspects—minimum energy per bit relates to energy efficiency, and channel dispersion deals with finite-length performance—not the maximum reliable rate.

The idea here is channel capacity—the highest data rate at which information can be transmitted over a noisy channel without error in the limit of long code blocks. For a channel with bandwidth and a given signal-to-noise ratio, the ultimate limit is the Shannon capacity: C = B log2(1 + S/N). This bound, known as the Shannon limit, says that no matter how clever your modulation and coding, you can’t reliably exceed this rate; below it, there exist coding schemes that can approach error-free transmission as blocklength grows. The other concepts describe different aspects—minimum energy per bit relates to energy efficiency, and channel dispersion deals with finite-length performance—not the maximum reliable rate.