Table 1 Notations of variables
From: A non-data-aided SNR estimator based on maximum likelihood method for communication between orbiters
Notations | |
|---|---|
L | Sampling points |
N | The number of simulation symbols |
R | Rolloff coefficient |
Q | Tap coefficients |
α | Signal amplitude |
αn | The phase of signal |
sn | The binary source symbols |
ck | The upsampled information sequence |
δij | The Kronecker delta |
hk | The tap coefficients of the RRC filter |
dk | The signal after being sampled and pulse-shaped |
wk | The additive white Gaussian noise |
σ2 | The variance of AWGN |
rk | The received signal |
yk | The output of the MF |
yn | The downsampled signal of yk |
fk | The samples of the full raised-cosine |
f0 | The peak of fk |
zn | The downsampled and filtered samples of noise |
ρ | Signal-to-noise ratio |
P(·) | The probability density function |
LN | The log-likelihood function |
θ | The estimated parameter vector |
g(θ) | The decibel scale of θ |
CRLB | Cramer-Rao lower bound |
K(θ) | Fisher information matrix |
\( \hat {\rho } \) | The estimate value of SNR |