Carrier-to-noise ratio for configured satellite link budget parameters
Calculate CNR and Link Margin
Calculate the CNR and the received link margin for the specified link budget parameters.
Create a default CNR configuration object, and then set its properties.
cfg = satelliteCNRConfig; cfg.TransmitterPower = 17; % in dBW cfg.TransmitterSystemLoss = 9; % in dB cfg.TransmitterAntennaGain = 38; % in dBi cfg.Distance = 40215; % in km cfg.Frequency = 11; % in GHz % Here, miscellaneous losses include polarization loss, interference % loss, and antenna mispointing loss, respectively. polLoss = 3.0103; intLoss = 2; antLoss = 1; cfg.MiscellaneousLoss = polLoss + intLoss + antLoss; % in dB cfg.GainToNoiseTemperatureRatio = 25; % in dB/K cfg.ReceiverSystemLoss = 2; % in dB cfg.BitRate = 10; % in Mbps
Display the CNR configuration object properties.
satelliteCNRConfig with properties: TransmitterPower: 17 TransmitterSystemLoss: 9 TransmitterAntennaGain: 38 Distance: 40215 Frequency: 11 MiscellaneousLoss: 6.0103 GainToNoiseTemperatureRatio: 25 ReceiverSystemLoss: 2 BitRate: 10 SymbolRate: 10 Bandwidth: 6
Calculate the CNR.
[cn,info] = satelliteCNR(cfg)
cn = 18.4440
info = struct with fields: TransmitterEIRP: 46 FSPL: 205.3634 ReceivedIsotropicPower: -165.3737 CarrierToNoiseDensityRatio: 86.2255 ReceivedEbNo: 16.2255 ReceivedEsNo: 16.2255
Compute the link margin. Assume a required energy per bit to noise power density ratio (Eb/No) of 10 dB and an implementation loss of 2 dB in the receiver.
reqEbNo = 10; implLoss = 2; margin = info.ReceivedEbNo - reqEbNo - implLoss
margin = 4.2255
cfg — CNR configuration object
CNR configuration object, specified as a
cn — Carrier-to-noise ratio
Carrier-to-noise ratio in dB, returned as a scalar. For more information, see Algorithms.
info — Intermediate results in CNR calculation
Intermediate results in the CNR calculation, based on the link budget parameters
specified in the configuration object
cfg returned as a structure
with these fields.
For more information, see Algorithms.
Effective isotropic radiated power (EIRP) of the transmitter antenna, returned as a scalar. Value is in dBW.
Free space path loss (FSPL) from the transmitter to the receiver antenna, returned as a scalar. Value is in dB.
Received isotropic power at the receiver antenna, returned as a scalar. Value is in dBW.
Carrier-to-noise power density ratio (C/No), returned as a scalar. Value is in dB-Hz.
Received energy per bit to noise power density ratio (Eb/No), returned as a scalar. Value is in dB.
Received energy per symbol to noise power density ratio (Es/No), returned as a scalar. Value is in dB.
All fields in the structure are of data type
The CNR for a satellite communications system measures the strength of the carrier signal at a receiver relative to the strength of the noise at that receiver. This diagram shows the various signal losses and gains involved in satellite communications.
To compute the CNR
cn for a system, the
satelliteCNR function performs various intermediate calculations, using
the properties of the
configuration object, and outputs them to a structure,
info. The function
uses these formulas for the intermediate calculations.
The function then computes the carrier-to-noise ratio using this formula:
cn = CarrierToNoiseDensityRatio - 10*log10(Bandwidth) -
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