Simulations and results » History » Version 10

GAY, Adrien, 03/23/2015 11:11 AM

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h1. Simulations and results
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From the method described previously, we have developed three Matlab programs enabling to compute or visualize the influence of various parameters according to what is assume known or not. 
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h2. Computation of the MODCOD and (G/T) required:
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Supposing that the specifications and frequency band are known (_Rb, R, f, B_ and _EIRP_ are known), we directly get all the parameters for the system design by following the method described previously.
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_+f= 869,5 MHz    B= 250 kHz    PAR= 0.5 W    Rb=500 bits/s    R=50 km:+_
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p=. !850M-MODCOD-GoT.png!
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Comment value (G/T)
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_+f= 5 GHz	  B= 500 kHz	EIRP= 1 W	Rb=500 bits/s	  R=50 km:+_
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p=. !5G-MODCOD-GoT.png!
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Comment value (G/T)
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h2. Influence of the bandwidth on the EIRP:
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If the regulatory frequency for application is known, this tool enables to visualize the tradeoff between the EIRP and bandwidth to fulfil the specifications:
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_+f= 869,5 MHz	  Rb=500 bits/s       R=50 km:+_
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p=. !850M-BW_vs_EIRP.png!
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Comments
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_+f= 5 GHz          Rb=500 bits/s       R=50 km:+_
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p=. !5G-BW_vs_EIRP.png!
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Comments
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h2. Influence of the distance on the bite rate:
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If the required system design is too constraining for a given specification, and then not achievable, we might lower our expectations and have a tradeoff between the desired bit rate and the range
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_+f= 869,5 MHz	B= 250 kHz	PAR= 0.5 W+_
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p=. !850M-range_vs_Bit_rate.png!
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_+f= 5 GHz	B= 500kHz	EIRP= 1 W+_
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p=. !5G-range_vs_Bit_rate.png!
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We can notice the bite rate is dropping quickly with the range of transmission. Then, the video transmission can be lost if the aircraft moves just a little bit too far of the limit range.