Frequency bands adapted to this project » History » Version 3
Version 2 (AUGER, Anne sophie, 03/23/2015 11:37 AM) → Version 3/10 (AUGER, Anne sophie, 03/23/2015 11:41 AM)
h1. Frequency bands adapted to this project
* *License-free band*
For the design of radio systems of small range with no license dedicated to data transmission, special authorized frequency bands exists and low emission power, lead to simple et efficient solution. These bands are précised in the Annex ANNEX 7 of the TNRBF TNRBF, which specifies the free bands with no license. They are a simple solution dedicated to the frequency research. There is no need to request a frequency band to the ANFR, any user with this type of equipment can use. low range and power equipment. In particular, the section for non-specific equipment is particularly adapted for TM/TC activities, data and video transmission (c.f. [[ANNEX I]] ).
Considering the high range required for the link (minimum 50km), there are two suitable bands with different characteristics:
* 868,7-869,2 MHz offers a 500 kHz bandwidth and ERP=25 mW leading to EIRP=41 mW
* 869,4-869,65 MHz offers a 250 kHz bandwidth and ERP=500 mW leading to EIRP=820 mW
With
bq. ERP: effective radiated power (ERP), often used to describe low frequencies systems.
EIRP: effective isotropic radiated power (EIRP), often used to describe high frequencies systems.
And
p=. *EIRP=ERP ×1,64*
Considering our application, the 500 mW ERP band seems to be better adapted, but there is a trade off to make with the bandwidth available, especially for the video transmission that requires large bandwidth.
p=. !868.png!
Although it appears to be the fastest and easiest way to define the frequency range of a system, the use of a free band is risky for the user. Indeed, there are no guaranties of non-jamming for users of license-free radio systems. In our case, a permanent link should be maintained between the aircraft and the ground station, considering that the aircraft will fly around the city of Toulouse and transmit uniformly to a region of more than 100km all around its antenna. We cannot allow that telecommand data don’t reach the aircraft, or that ground station loose the telemetry information of the plane: the solution is to send a frequency allocation request to the ANFR.
* *License band*
Regulatory aspects are parameters that define the system but yet don’t depend on the user. The process of frequency allocation is long and administratively complex, that’s why we asked for information about frequency allocation process at an early stage of the project. In the mean time, as the answers were sending us back to the TNRBF, we decided to consider free bands, but we soon realised it was not a reliable solution for our design.
Our first idea was to search for frequency bands dedicated to the service named MBA (Mobile for Aeronautical services) and affected to the user DEF (Ministry of Defence), because ISAE is under the tuition of Defence Ministry. There, we find an available band 5091-5150 MHz (c.f. [[ANNEX II]] ). If the ANFR accepts our request, it will provide specify the sub-band available for our application, and the emission power authorized for our equipment.
At the end of this project, the process of the frequency band request has not succeeded yet. However, we have reached an interlocutor within the frequency office of the DGSIC, Dominique Pizzol, and the result of our discussion should come up soon.
* *Methodology for the project*
We choose to study the performance of the system design considering the two previous bands : 869,4-869,65 MHz, and 5091-5150 MHz, in order to keep doors opened and see the influence of both bands.
In order to simulate the system performance and find the required parameters, we need the EIRP and bandwidth available for the our application in the 5091-5150 MHz band. According to our research in the litterature, we will fix the bandwidth to 5OO kHZ, and the EIRP to 1W.
* *License-free band*
For the design of radio systems of small range with no license dedicated to data transmission, special authorized frequency bands exists and low emission power, lead to simple et efficient solution. These bands are précised in the Annex ANNEX 7 of the TNRBF TNRBF, which specifies the free bands with no license. They are a simple solution dedicated to the frequency research. There is no need to request a frequency band to the ANFR, any user with this type of equipment can use. low range and power equipment. In particular, the section for non-specific equipment is particularly adapted for TM/TC activities, data and video transmission (c.f. [[ANNEX I]] ).
Considering the high range required for the link (minimum 50km), there are two suitable bands with different characteristics:
* 868,7-869,2 MHz offers a 500 kHz bandwidth and ERP=25 mW leading to EIRP=41 mW
* 869,4-869,65 MHz offers a 250 kHz bandwidth and ERP=500 mW leading to EIRP=820 mW
With
bq. ERP: effective radiated power (ERP), often used to describe low frequencies systems.
EIRP: effective isotropic radiated power (EIRP), often used to describe high frequencies systems.
And
p=. *EIRP=ERP ×1,64*
Considering our application, the 500 mW ERP band seems to be better adapted, but there is a trade off to make with the bandwidth available, especially for the video transmission that requires large bandwidth.
p=. !868.png!
Although it appears to be the fastest and easiest way to define the frequency range of a system, the use of a free band is risky for the user. Indeed, there are no guaranties of non-jamming for users of license-free radio systems. In our case, a permanent link should be maintained between the aircraft and the ground station, considering that the aircraft will fly around the city of Toulouse and transmit uniformly to a region of more than 100km all around its antenna. We cannot allow that telecommand data don’t reach the aircraft, or that ground station loose the telemetry information of the plane: the solution is to send a frequency allocation request to the ANFR.
* *License band*
Regulatory aspects are parameters that define the system but yet don’t depend on the user. The process of frequency allocation is long and administratively complex, that’s why we asked for information about frequency allocation process at an early stage of the project. In the mean time, as the answers were sending us back to the TNRBF, we decided to consider free bands, but we soon realised it was not a reliable solution for our design.
Our first idea was to search for frequency bands dedicated to the service named MBA (Mobile for Aeronautical services) and affected to the user DEF (Ministry of Defence), because ISAE is under the tuition of Defence Ministry. There, we find an available band 5091-5150 MHz (c.f. [[ANNEX II]] ). If the ANFR accepts our request, it will provide specify the sub-band available for our application, and the emission power authorized for our equipment.
At the end of this project, the process of the frequency band request has not succeeded yet. However, we have reached an interlocutor within the frequency office of the DGSIC, Dominique Pizzol, and the result of our discussion should come up soon.
* *Methodology for the project*
We choose to study the performance of the system design considering the two previous bands : 869,4-869,65 MHz, and 5091-5150 MHz, in order to keep doors opened and see the influence of both bands.
In order to simulate the system performance and find the required parameters, we need the EIRP and bandwidth available for the our application in the 5091-5150 MHz band. According to our research in the litterature, we will fix the bandwidth to 5OO kHZ, and the EIRP to 1W.