For those that would like to read more about the O3B project go to their web site here: https://www.o3bnetworks.com/
8 satellites are launched simultaneously and then deployed in pairs from the upper stage. Only two launches will therefore be needed to put up the 16 satellites. There are 12 spot beam antennas shown on each satellite, presumably each actively steering.
The satellites are all in circular orbit, above the equator, height 8000 km, so will be seen to be moving forwards, eastwards. Ground users will have to keep switching backwards to more westerly satellites every 15 minutes or so as the satellites march eastwards. This page https://www.satsig.net/O3b/O3b-orbit.htm
should give you some idea. Quote:
A) 1Mb/s to 10Gb/s per backhauling connection link.
Assuming use of 500 MHz in each of the bands 19.7-20.2 and 29.5-30.0 GHz and single polarisation, each spot beam could have 500 MHz bandwidth. If 300 MHz is used for downloads, that could provide 936 Mbit/s using 16APSK DVB-S2. Times that by 12 beams and you get around 10 Gbit/s which seems reasonable. It might be much more if they use more of the Ka frequency band or dual polarisation. DVB-S2 has the advantage it can drop back to lower modulation/coding during rain or to cope with beam edge or customer earth station deficiencies. Quote:
B) They state the system made up of 16 satellites for the initial phase to support 2133 transponders, this would mean 133 transponders per satellite, in your case you state 15 transponders per satellite.
Strange number that 2133. My guess is 1 downlink and I uplink transponder in each of the 10 customer beams.
I believe that two satellite antenna will be used for gateway feeder links and that 10 satellite antennas will be used for 10 customer sites, each covered by a spot beam.
Will it work ? Much depends in the customer antennas, tracking (1.2m - 7.6m) and working in pairs. The satellite power (watts) per transponder is also important and again I can find no information. Quote:
C) They also say that the cost of internet backhauling would be 500$ per Mb/s per month against 4000$ of competing systems.
I am pleased to see someone trying to get the costs down. The present prices of $4000 to $7000 per month per 1 Mbit/s are too high for most people. Much will depend on how cheap they can get the satellites manufactured and launched and the financial viability will depend on how quickly they can build up the number of customers paying. They will be watching the progress of Wildblue, Ka-Sat and ViaSat-1
I hope this O3B project does not go the way of other LEO and MEO satellite projects of the 1990's.
If anyone knows more about the proposed O3B customer antenna, how the satellite antennas will be pointed or the ground infrastructure please say.
Best wishes to all involved.
Best regards, Eric.