The "C/N" ratio resembles the carrier-to-interference ratio ("C/I ", CIR), and the carrier-to-noise-and-interference ratio,"C/(N + I)" or CNIR.
The "C/N" ratio resembles the carrier-to-interference ratio ("C/I ", CIR), also known as the signal-to-interference ratio ("S/I ", SIR). These mesures are approximately equivalent to the carrier-to-noise-and-interference ratio,"C/(N + I)" or CNIR.