Estimation of single-to-noise ratio by processing measured error vector magnitude

Abstract

The signal-to-noise ratio of a demodulated received signal is estimated by measuring the error vector magnitude (EVM) of the demodulated signal; and processing the measured EVM in combination with a correction term to estimate the signal-to-noise ratio of the demodulated signal. The correction term is a polynomial function of the measured EVM. The signal-to-noise ratio is estimated in accordance with the formula: E S N 0 ≅ 10 · LOG 10 ⁡ ( π · ⌈ E S ⌉ 4 ⁡ [ μ ^ z + C ⁡ ( μ ^ z ) ] 2 ) ⁢ ⁢ ( dB ) wherein {circumflex over (μ)}z is the measured EVM based on the mean of a Rayleigh density of EVM measurements; and C is the correction term. For QPSK modulated signals, C is calculated in accordance with the formula: CQPSK({circumflex over (μ)}z)≅2.71×10−3{circumflex over (μ)}z3−7.54×10−2{circumflex over (μ)}z2+0.7{circumflex over (μ)}z−2.25. For BPSK modulated signals, C is calculated in accordance with the formula: CBPSK({circumflex over (μ)}z)≅1.78×10−4{circumflex over (μ)}z3−1.03×10−3{circumflex over (μ)}z2+4.62×10−2{circumflex over (μ)}z−0.588.

Dependencies are inferred from the claim text.