Apparatus, method, and computer program products for cell-hopping satellite communications

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is described in terms of the above example.
This is for convenience only and is not intended to limit the application of the present invention.
In fact, after reading the following description, it will be apparent to one skilled in the relevant art how to implement the present invention in alternative embodiments.
A preferred embodiment is described below in terms of the satellite downlink, the present invention is equally applicable to a satellite uplink.
The present invention combines the flexibility of a hopped multi-beam antenna system with a novel frequency/time assignment technique that takes advantage of the relative traffic demand in each coverage cell.
A multi-beam phased array antenna is used, and hops are controlled electronically.
Each beam can therefore service multiple smaller size cells (approximately 0.
5 dB beamwidth), yielding a higher capacity focus without sacrificing the size of the coverage area.
One advantage of this method is that it is driven by traffic demands.
Instead of the traditional way of dividing the frequency resources uniformly in space, this method takes advantage of the non-uniform traffic demands and optimizes the frequency assignment to maximize the total system capacity.
In order to maintain a specified carrier to interference ratio (C/I), a global time multiplex access scheme is superimposed on the frequency assignment to control the interference level.
The result is an FDMA/TDMA/Hopped Beam technique which emphasizes the FDMA aspect in high traffic demand regions to achieve higher capacity with minimum interference, and emphasizes the TDMA aspect in low traffic demand areas to achieve the same relative capacity with minimum frequency resources.
Hopping of the beams makes this scheme feasible.
When the beam-hopping assignments are fixed in a "coverage template", the coverage can be implemented using a software script that digitally commands each beam in the antenna system to be steered to its designated coverage cell at a specified time