| 摘要 |
<p>Systems and methods for transmitting and receiving additional data, such as video data, over legacy satellite digital audio radio signals are provided. In exemplary embodiments, hierarchical modulation can be used to transmit secondary information over a legacy signal. For example, the Sirius Satellite Digital Audio Radio Service ("SDARS") system may use a second layer of modulation to transmit video data on top of its regular audio signal. In order to support such future services within the original system design, sometimes referred to herein as a "legacy" system, additional information bandwidth can be acquired, for example, by using hierarchical modulation to overlay data for such new services on top of the legacy transmission. In such a system, for example, overlay data can be transmitted by applying a programmable angular offset to legacy QPSK symbols, for forming a new constellation similar to 8PSK.</p> |
