Noise Floor Table

Quick-reference noise-floor values for common bandwidths and noise figures, plus the receiver sensitivity identity. Companion to Concepts / AWGN.

Noise floor at \(T_0 = 290\) K

Bandwidth	\(P_n\) at \(NF = 0\) dB (290 K)	\(P_n\) at \(NF = 5\) dB
1 Hz	\(-174\) dBm	\(-169\) dBm
180 kHz (LTE PRB)	\(-121.45\) dBm	\(-116.45\) dBm
1 MHz	\(-114\) dBm	\(-109\) dBm
20 MHz (Wi-Fi 802.11)	\(-101\) dBm	\(-96\) dBm
100 MHz (5G NR FR1)	\(-94\) dBm	\(-89\) dBm
160 MHz (Wi-Fi 802.11ac)	\(-92\) dBm	\(-87\) dBm
1 GHz (mmWave research)	\(-84\) dBm	\(-79\) dBm

All values use \(P_{n,\,dBm} = -174 + 10 \log_{10}(B_{Hz}) + NF_{dB}\) [2]. The \(-174\) dBm/Hz floor is the kT0 reference at 290 K (the IEEE reference temperature [3]).

Receiver sensitivity

Sensitivity, the minimum detectable signal power, is

\[P_{\text{min},\,dBm} = -174 + 10 \log_{10}(B_{Hz}) + NF_{dB} + (E_b/N_0)_{\text{required},\,dB} + 10 \log_{10}(R_b)\]

where \(R_b\) is the data rate. The first three terms are the noise floor; the last two are the demodulation requirement. This identity is the basis of every link budget [3].

See Also

• Concepts / AWGN for the kTBF model and Sionna integration.

• Concepts / Channels / RX Frontend for the LNA noise figure that feeds this table.

References

1. Nyquist, H. Thermal Agitation of Electric Charge in Conductors, Phys. Rev., 1928.

2. Friis, H. T. Noise Figures of Radio Receivers, Proc. IRE, 1944.

3. Sklar, B. Digital Communications: Fundamentals and Applications, 2nd ed., Prentice Hall, 2001. (Link budget; Eb/N0 framework)