Method and system for transmitting satellite signals and receiver thereof

• US 9,883,256 B2
• Filed: 09/02/2014
• Issued: 01/30/2018
• Est. Priority Date: 09/09/2013
• Status: Active Grant

• Current Assignee: RAI Radiotelevisione Italiana SPA (Government of Italy)
• Original Assignee: RAI Radiotelevisione Italiana SPA (Government of Italy)
• Inventors: Morello, Alberto, Mignone, Vittoria, Sacco, Bruno
• Primary Examiner(s): Pendleton, Brian T
• Assistant Examiner(s): Luong, Alan
• Application Number:
  US14/912,548
• Publication Number:
  US 20160212505A1
• Time in Patent Office: 1,246 Days
• Field of Search: 380255, 375259, 725 63, 370312
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 5/0042 intra-user or intra-terminal allocation
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 65/61 for supporting one-way streaming services, e.g. Internet radio
• CPC Class Codes: H04N 21/23655 Statistical multiplexing, e.g. by controlling the encoder to alter its bitrate to optimize the bandwidth utilization
• CPC Class Codes: H04N 21/6143 involving transmission via a satellite
• CPC Class Codes: H04N 21/8547 involving timestamps for synchronizing content

Abstract

A transmission system, a receiver and a method for satellite signal transmission, wherein the satellite signals includes respective data streams consisting of a sequence of data packets. The method includes: subdividing the data packets of the data stream, through a splitter, into a first and at least one second data pseudo-streams; modulating the first and at least one second data pseudo-streams through a first and at least one second modulators, respectively; transmitting the modulated data pseudo-streams through respective transmission channels (Ch#1 . . . Ch#N), wherein, in order to generate the data pseudo-streams, the splitter will: select each data packet of the data stream; interrogate the modulators in a sequential manner in order to identify that modulator which, among the modulators, is available to accept the data packet, and send the latter to it; send a null data packet to the remaining modulators.

Claims

1. A method for transmitting a satellite signal comprising a data stream that includes a sequence of data packets, said method comprising:

subdividing said data packets of said data stream, through means for splitting, into a first and at least one second data pseudo-streams;

modulating said first and said at least one second data pseudo-streams through a first and at least one second modulators, respectively;

transmitting said modulated data pseudo-streams through respective transmission channels,

wherein, in order to generate said data pseudo-streams, said means for splitting will;

select each data packet of said data stream;

interrogate said modulators in a sequential manner in order to identify that modulator which, among said modulators, is available to accept said data packet, and send the latter to it;

send a null data packet to the remaining modulators.

2. The method according to claim 1, wherein said transmission system uses a reference clock associated with a master modulator included in said modulators, said reference clock operating a counter block, which is in signal communication with said modulators and is driven at a cadence of a symbol rate of said master modulator, and wherein a value of said counter block is added to each data packet as said data packet enters the modulator.

3. The method according to claim 2, wherein said stream is a single-type MPEG-TS stream, wherein an “

Input Stream Synchronizer”

functionality is activated in said modulators.

4. The method according to claim 3, wherein said stream is a single-type MPEG-TS stream, wherein a Null Packet Deletion mode and/or the Dummy Frame Insertion mode are activated in said modulators.

5. The method according to claim 1, wherein a transmission rate adapter system is disabled in said modulators.

6. The method according to claim 1, wherein a packet continuity counter function is disabled in said modulators.

7. The method according to claim 1, wherein said means for splitting are controlled through respective control signals coming from said modulators.

8. The method according to claim 1, wherein said means for splitting are controlled in a deterministic manner so that, being the spectral efficiency of the i-th modulator and mcd being the lowest common denominator of the spectral efficiencies η

₁, . . . , η

_N, said means for splitting will pack said first and said at least one second pseudo-streams according to a time periodicity equal to (η

₁₊ . . . +η

_N)×

mcd packets of said data stream, so that, given a period of said data stream, said pseudo-streams will have the same period, within which the i-th pseudo-stream will contain η

_i×

mcd data packets extracted from the data stream and the remaining packets will be null, and wherein the time positions of the packets of the data stream will be kept unchanged in the pseudo-streams.

9. The method according to claim 1, wherein Service Information tables are transmitted on said pseudo-streams, said tables containing information necessary for knowing the frequency positions of the channels bonded together for transmitting said data stream and for identifying a master channel.

10. The method according to claim 9, wherein, when a packet of said data stream contains a piece of information of the Service Information table, the presence of said piece of information being indicated by the PID field in the header of said packet, said packet will be simultaneously sent to all of said pseudo-streams in derogation of the above-described mechanism, so that no pseudo-stream will contain a null packet.

11. A transmitter comprising:

a splitter configured to receive a data stream; and

wherein the splitter is configured to subdivide data packets of said data stream into a first and at least one second data pseudo-streams;

a first and at least one second modulator configured to modulate, respectively, said first and said at least one second data pseudo-streams;

a transmitter configured to transmit said modulated data pseudo-streams through respective transmission channels,

wherein, in order to generate said data pseudo-streams, said splitter is configured to;

select each data packet of said data stream;

interrogate said modulators in a sequential manner in order to identify that modulator which, among said modulators, is available to accept said data packet, and send the latter to it;

send a null data packet to the remaining modulators.

12. A method for receiving a satellite signal comprising a data stream that includes a sequence of data packets, said method comprising the steps of:

receiving modulated data pseudo-streams through respective transmission channels;

demodulating said first and said at least one second data pseudo-streams through a first and at least one second demodulators, respectively;

merging said first and said at least one second data pseudo-streams, through means for merging, in order to reconstruct a data stream comprising packet sequences, wherein, in order to reconstruct said packet stream, said means for merging will;

re-align said packet pseudo-streams on the basis of the value of a field of said data packet;

select, for each data packet of said re-aligned pseudo-streams, the one that contains a non-null packet;

insert said non-null packet into the reconstructed data stream.

13. The method according to claim 12, wherein a Null Packet Reinsertion mode is activated in said demodulators.

14. The method according to claim 12, wherein said pseudo-streams are re-aligned on the basis of an ISCR (“

Input Stream Clock Reference”

) subfield transmitted in an ISSY (“

Input Stream Synchronizer”

) field.

15. The method according to claim 12, wherein said data pseudo-streams are re-aligned on the basis of a “

Continuity Counter”

field included in the header of each data packet of each service contained in the data stream, said data stream being an MPEG-TS stream, and/or on the basis of a “

Program Clock Reference”

field included in the header of each data packet of each service contained in said MPEG-TS stream.

16. The method according to claim 13, wherein said means for merging, when receiving non-null packets from all of said pseudo-streams with a PID indicating a piece of information in the Service Information table, will select any one of said packets by also taking into account the transmission error indicator field in the header of said packet.

17. The method according to claim 12, wherein, if at a certain time instant all the packets of said pseudo-streams are null packets, then said means for merging will insert a null packet into the reconstructed data stream.

18. The method according to claim 12, wherein said means for merging comprise a memory block for each input of said means for merging, so that they can accommodate the differential delay to be compensated for on said transmission channels.

19. A receiver for receiving a satellite signal that includes a data stream including a sequence of data packets, the receiver comprising:

a receiver configured to receive modulated data pseudo-streams through respective transmission channels, wherein the modulated data pseudo-streams include a first and at least one second data pseudo-stream;

a first and at least one second demodulator configured to demodulate, respectively, said first and said at least one second data pseudo-streams;

a merger configured to merge said first and said at least one second data pseudo-streams in order to reconstruct the data stream that includes the sequence of data packets,

wherein, in order to reconstruct said packet stream, said merger is configured to;

re-align said packet pseudo-streams on a basis of a value of a field of said data packet;

select, for each data packet of said re-aligned pseudo-streams, the one that contains a non-null packet; and

insert said non-null packet into the reconstructed data stream.

20. The receiver according to claim 19, wherein, if at a certain time instant all said data packets of said pseudo-streams are null packets, then said merger is configured to insert a null packet into the reconstructed data stream.