| 摘要 |
In exemplary embodiments of the present invention, a degree of hierarchical modulation can be vaned as a function of satellite position, which can be related to time of day, and where such hierarchical modulation can be a combination of phase and amplitude shifts. In exemplary embodiments of the present invention, as each satellite in a multiple satellite system broadcasting to North America moves towards a D-node or an A-node position, the offset angle of a phase-based hierarchical modulation scheme can be varied. Thus, in exemplary embodiments of the present invention, the lowest satellite position In the sky can have the lowest offset angle for overlay bits, which offset angle can, for example, progressively increase as the position of the satellite in the sky increases. At a satellite's highest point in the sky, the overlay offset angle can, for example, thus be at its maximum. |
