Method of improving performance in a hierarchical modulation system
First Claim
1. A method of hierarchically modulating a transmission frame including an overlay layer modulated onto a base layer, the base layer providing basic service and the overlay layer providing additional services, the method comprising:
- synchronously aligning an overlay layer frame to a base layer frame;
generating a master frame of the base layer comprising the aligned frame by inserting additional data bits at the beginning of the aligned frame and at a selected interval throughout the aligned frame, wherein the aligned frame comprises payload bits for the base layer service and the overlay layer service, and the additional data bits are synchronization bits related to a synchronization bit or pattern of the base layer;
modulating the synchronization bits of the master frame using a first modulation technique; and
hierarchically modulating the payload bits of the master frame using a second modulation technique based on the first modulation technique.
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Accused Products
Abstract
A method is provided for enhancing a legacy satellite digital radio audio service (SDARS) by overlaying a hierarchically modulated data stream on a base layer (legacy) data stream and improving the synchronization of the received signal in which an overlay layer frame is synchronized to a base layer frame. The base layer frame includes additional data that is used to synchronize the receivers to demodulate and decode the overlay layer and the base layer. The additional data is modulated using a technique that aids the receiver in synchronizing the received signal that is different from the overlay layer.
41 Citations
19 Claims
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1. A method of hierarchically modulating a transmission frame including an overlay layer modulated onto a base layer, the base layer providing basic service and the overlay layer providing additional services, the method comprising:
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synchronously aligning an overlay layer frame to a base layer frame; generating a master frame of the base layer comprising the aligned frame by inserting additional data bits at the beginning of the aligned frame and at a selected interval throughout the aligned frame, wherein the aligned frame comprises payload bits for the base layer service and the overlay layer service, and the additional data bits are synchronization bits related to a synchronization bit or pattern of the base layer; modulating the synchronization bits of the master frame using a first modulation technique; and hierarchically modulating the payload bits of the master frame using a second modulation technique based on the first modulation technique. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A computer readable medium having instructions stored thereon for modulating a transmission frame including an overlay layer modulated onto a base layer, the base layer providing basic service and the overlay layer providing additional services, the instructions performing the steps of:
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synchronously aligning an overlay layer frame to a base layer frame; generating a master frame of the base layer comprising the aligned frame by inserting additional data bits at the beginning of the aligned frame and at a selected interval throughout the aligned frame, wherein the aligned frame comprises payload bits for the base layer service and the overlay layer service, and the additional data bits are synchronization bits related to a synchronization bit or pattern of the base layer; modulating the synchronization bits of the master frame using a first modulation technique; and hierarchically modulating the payload bits of the master frame using a second modulation technique based on the first modulation technique. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification