downlinkbd.m

卫星链路的计算

function SNR = downlinkbd()
% this function perform satellite downlink budget

SatPower = 18;       % transmission power from satellite, dBW.
SatLoss = -1;        % loss of transmission satellite, dB.
SatGain = 16;        % antenna gain of transmission satellite, dB.
AtmoLoss = 0;        % loss of atmosphere, dB.
SpaceLoss = -197;    % path loss through free space, dB.
ESReGain = 51;       % receiving antenna gain of earth station, dB.
ESReLoss = -1;       % receiving antenna loss of earth station, dB.
OutBackoff = 0;      % TWTA output backoff, -dB
ESRePower = SatPower+SatLoss+SatGain+AtmoLoss+SpaceLoss+ESReGain+ESReLoss+OutBackoff;
                     % satellite receiving power, dBW.
                  
NoiseTp = 160;       % System Noise Temperature, Kelvin.
Bandwidth = 350e+6;   % bandwidth, Hz
k = 1.38054e-23;
NoisePower = 10*log10(k*NoiseTp*Bandwidth);

RainLoss = -2;       % loss brought by rain

SNR = ESRePower-NoisePower+RainLoss;
                     % signal to noise ratio