System and methods to reclaim unused throughput in an SDARS system
Systems, algorithms and methods for reclaiming unused portions of a satellite broadcast service's bandwidth for new services, utilizing higher performance coding techniques to yield better throughput, are presented. These systems, algorithms and methods achieve the reclaimed bandwidth in a way that is invisible to a legacy receiver, and that does not interfere with its reception of a legacy signal. In one embodiment, new data may be transmitted within a legacy transmission frame, for example within its cluster structure, using the same modulation and synchronization as used for the legacy data. The new data may be inserted into a channel or other subdivision at a head end. In another embodiment, one or more clusters or subdivisions with only new data may be transmitted, using the same modulation and synchronization as the legacy data clusters, but now employing a higher performing FEC and data interleaving structure on those clusters which contain only new data to yield an increase in available throughput. Finally, in a third embodiment, one or more clusters containing only new data may be transmitted, and in said one or more all new data clusters, different modulation and synchronization may be used then that of the legacy data clusters, thus employing a higher performing FEC and data interleaving structure than that of the legacy clusters. Various combinations of these approaches are also presented, as well as a set of novel receivers, or receiver configurations, to implement them and their combinations.
1. A method of reclaiming unused legacy bandwidth in a broadcasting system having a broadcast transmission frame with at least two divisions, the method comprising:
encoding legacy data using a first modulation and synchronization scheme;
encoding new content data using a second modulation and synchronization scheme different from the first modulation and synchronization scheme;
transmitting one or more other transmission frame divisions containing the encoded legacy content data; and
transmitting one or more transmission frame divisions containing only the encoded new content data such that a legacy receiver would not see the divisions containing new data, but receivers configured to decode the new content data would;
wherein the one or more transmission frame divisions containing solely new content data are processed using a higher performing FEC and data interleaving structure than that of the other divisions that contain any legacy content data.
2. The method of claim 1 , further comprising, in addition to the divisions containing solely new content data, transmitting additional new data within at least one of the other transmission frame divisions that contain legacy content data, using the same modulation and synchronization as the legacy data divisions.
3. The method of claim 1 , further comprising inserting the encoded new content data into the broadcast transmission frame such that a legacy receiver would not see the divisions containing the new content data, but receivers configured to decode the new content data would.
4. The method of claim 1 , wherein the legacy transmission frame data is modulated using both a primary and a secondary layer of modulation, the new content data in said new content data divisions is modulated at the primary layer of modulation, and the secondary layer of modulation operates on both divisions containing legacy content and divisions containing only new content data.
5. The method of claim 1 , further comprising sending additional new content data in one or more transmission frame divisions that contain legacy data.
6. The method of claim 1 , further comprising sending additional new content data in one or more transmission frame divisions that contain legacy data and sending extraction information relative to any new content data in any combined division having both new content data and legacy data.
7. The method of claim 1 , further comprising sending additional new content data in one or more transmission frame divisions that contain legacy data and sending extraction information relative to the new content data through one or more out of band messaging schemes.
8. The method of claim 1 , further comprising sending additional new content data in one or more transmission frame divisions that contain legacy data and sending extraction information relative to the new content data within the at least one transmission frame, said extraction information arranged to instruct a receiver how to separate the new content data from other data during decoding.
9. The method of claim 1 , wherein divisions containing solely new content data are interleaved with other divisions containing wholly or partially legacy data.
10. The method of claim 1 , wherein the transmission frame division is one of a cluster, a cluster segment, a channel, or a physical channel.
11. The method of claim 1 , wherein the higher performing FEC includes one of Turbo or Low Density Parity Check codes, and wherein the higher performing data interleaving structure includes at least one of a programmable convolutional interleaver, or an interleaver with significantly greater delay spreads over a fixed duration of the legacy system.
12. A system, comprising:
a transmitter comprising a legacy encoding module, a hierarchical modulation encoding module and a multiplexer; and
a receiver comprising a legacy demodulator, a new data demodulator, a legacy decoding module, a hierarchical modulation decoding module, and a new data decoding module, wherein the transmitter is configured to encode and transmit new content data and legacy content data, the new content data sent in one or more transmission frame divisions containing only new content data, and
wherein the receiver is configured to:
demodulate the legacy content data divisions in the legacy demodulator and send the demodulated data to the legacy decoding module and the hierarchical modulation decoding module,
demodulate the new content data in the new data demodulator, and send the demodulated new data divisions to the new data decoding module;
wherein the only new content containing divisions are modulated differently by the transmitter than the other divisions containing legacy data.
13. The system of claim 12 , wherein the only new content containing divisions are modulated using include a combination of QPSK, 8PSK, 16QAM, C16QAM or other multi-symbol scheme.
14. The system of claim 12 , wherein the only new content containing divisions are not hierarchically modulated, but integrated as a singly modulated division.
15. The system of claim 12 , wherein the transmitter is further configured to also encode and transmit combination divisions containing both new content data and legacy content data.
16. The system of claim 12 , wherein the transmitter is further configured to also encode and transmit combination divisions containing both new content data and legacy content data.
17. The system of claim 12 , wherein the transmitter is further configured to also encode and transmit combination divisions containing both new content data and legacy content data, and wherein at least one of: the transmitter is further configured to send extraction information relative to any new content data in any combination division, extraction information relative to the new content data is sent through one or more in band or out of band messaging schemes, or the receiver is configured to demodulate the data in said combination divisions and then, at the legacy decoder, separate the new content data from the legacy content data using received extraction information.
18. The system of claim 12 , wherein the transmitter is configured to modulate all data in any division with a secondary modulation layer containing hierarchical modulation content.