Potential benefits of dynamic beam synthesis to mobile satellite communication

The latest communication satellites use high gain multi-beam antenna systems. These provide a contiguous set of beams covering a service area. In addition spatial frequency reuse is utilized to maximise channel capacity, requiring the beams to be spatially isolated from one another. Users are assigned to a beam that aligns with the geographic cell they occupy. The necessary isolation between users with the same frequency is provided by a pre-synthesised fixed beamset. Achieving the isolation requirement drives up the beam roll-off rate, leading to ~3dB loss at the edge of a beam. An alternative would be to synthesise the beams dynamically, making use of user locations, to both maximise an individual user's gain whilst minimising co-frequency interference from other uses. This paper outlines the potential benefit of dynamic beam synthesis (DBS) over a conventional fixed beam system.