PrdBm

PrdBm, sometimes written as Pr(dBm) or as P_r in dBm, denotes the received power at the input of a radio receiver expressed in decibels relative to one milliwatt. It is a primary figure of merit in wireless communication link budgets, receiver sensitivity, and overall performance assessment.

PrdBm is determined by the transmitted power, the gains of the transmitting and receiving antennas, and the propagation losses between them. A common shorthand for a simple link budget is PrdBm = Pt(dBm) + Gt(dBi) + Gr(dBi) − Lp(dB) − other losses, where Lp represents path loss. In free space, Lp can be estimated from the Friis transmission equation.

Path loss increases with distance and frequency and decreases with line-of-sight conditions. Received power typically falls into negative dBm values for many wireless systems; examples include Wi‑Fi and cellular signals at typical indoor distances, where PrdBm might range from about −30 dBm to −90 dBm depending on conditions. The exact value determines if the receiver can detect and demodulate the signal given its sensitivity and required signal-to-noise ratio.

Applications and caveats: PrdBm is used in link-budget calculations, link-margin analysis, and performance specification. It is important to distinguish PrdBm from transmitter measures such as EIRP or Pt(dBm). Environmental factors, fading, interference, and noise can cause instantaneous PrdBm to fluctuate, so performance is often described in terms of minimum required PrdBm or average PrdBm over a measurement interval.