If you had to consider some of the known systems, this particular slide shows only two known systems, IRIDIUM which the satellites are esteemed there, but not operational, for commercial purposes, globally start, we could see that IRIDIUM has got 66 satellites and 6 are in a spare in 6 orbits at a height of 780 kilometres and at an inclination of 86,4°, which basically means that it is almost going over the North Pole. They have 21 ground stations and the size consists of 48 cells per satellite and can provide voice data and fax connectivity. The special feature for IRIDIUM system is that it does have inter on board processing as well as inter-satellite link.
Inter-satellite link means that one could go up from a ground station to the satellite, from that satellite to another satellite, and finally to the intended user.