Interference analysis for spot beam partitioning in cellular satellite communication systems

It is observed that the sub-beam approach will reduce the gain requirements by 3 dB and 3.6 dB or partition factors of four and seven, respectively. This implies more than 50% reduction in the aperture size. The interference study shows that the partition factor of seven results in high levels of interference as the sub-beams are defined at only 0.4 dB down relative to the peak, and the half power beamwidth is quite broad so that spatial isolation can not work favorably to reduce interference levels. However, the partition factor of four produces similar interference levels as the spot beam configuration (26.92 versus 26.87) using only half of the aperture size. The investigation shows that the spot beam partitioning is a good technique to reduce the antenna size while maintaining the system requirements, such as edge gain and center to center interference.