SNR
Signal-to-Noise Ratio: the ratio of signal power to background noise power at the receiver, expressed in dB. Higher SNR enables higher-order modulation and better throughput.
SNR compares wanted signal power against background noise, in decibels. Because it is logarithmic, every 3 dB is a doubling — a detail worth internalising before you reason about link budgets. The reason engineers care is direct: SNR sets the ceiling on how much information a channel can carry, via Shannon's bound, and in practice it decides which modulation and coding scheme the network can safely use.
In a real cell, though, pure SNR is often the wrong metric. Noise is rarely the limiting factor in a dense network — interference from neighbouring cells is. That's why SINR, which folds interference in alongside noise, is usually what scheduling and reporting actually rely on. SNR stays relevant in noise-limited situations like a quiet rural cell edge or a lab measurement where there is little interference to speak of.
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