Apparatus, systems and methods for producing coherent symbols in a single frequency network

• US 7,738,582 B2
• Filed: 02/28/2006
• Issued: 06/15/2010
• Est. Priority Date: 03/02/2005
• Status: Active Grant

• Current Assignee: Rohde & Schwarz GmbH & Company KG
• Original Assignee: Rohde & Schwarz GmbH & Company KG
• Inventors: Simon, Michael
• Primary Examiner(s): Payne; David C
• Assistant Examiner(s): Panwalkar; Vineeta S
• Application Number:
  US11/276,434
• Publication Number:
  US 20060200852A1
• Time in Patent Office: 1,568 Days
• Field of Search: 375259-261, 375/265, 375/354, 375/256, 370/464, 370/498, 370/503, 370/505, 714/699, 714/746, 714/786, 714/792, 714/752, 714/775, 714/776, 714/789, 455/3.01, 455/3.02
• US Class Current: 375/265
• CPC Class Codes: H03M 13/15 Cyclic codes, i.e. cyclic shifts of codewords produce other codewords, e.g. codes defined by a generator polynomial, Bose-Chaudhuri-Hocquenghem [BCH] codes H03M13/17 takes precedence
• CPC Class Codes: H03M 13/151 using error location or error correction polynomials
• CPC Class Codes: H03M 13/23 using convolutional codes, e.g. unit memory codes
• CPC Class Codes: H03M 13/235 Encoding of convolutional codes, e.g. methods or arrangements for parallel or block-wise encoding
• CPC Class Codes: H03M 13/253 with concatenated codes
• CPC Class Codes: H03M 13/256 with trellis coding, e.g. with convolutional codes and TCM
• CPC Class Codes: H03M 13/2732 Convolutional interleaver; Interleavers using shift-registers or delay lines like, e.g. Ramsey type interleaver
• CPC Class Codes: H03M 13/2936 comprising an outer Reed-Solomon code and an inner convolutional code
• CPC Class Codes: H03M 13/6538 ATSC VBS systems
• CPC Class Codes: H04H 20/18 Arrangements for synchronising broadcast or distribution via plural systems
• CPC Class Codes: H04H 20/67 Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency
• CPC Class Codes: H04L 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/006 Trellis-coded modulation
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/009 arrangements specific to transmitters
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 27/02 Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation H04L27/32 takes precedence
• CPC Class Codes: H04L 27/2656 Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04N 21/235 : Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/23608 : Remultiplexing multiplex streams, e.g. involving modifying time stamps or remapping the packet identifiers
• CPC Class Codes: H04N 21/23611 : Insertion of stuffing data into a multiplex stream, e.g. to obtain a constant bitrate synchronisation arrangements in time-division multiplex systems using bit stuffing for systems with different or fluctuating information rates H04J3/073
• CPC Class Codes: H04N 21/2383 : Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/242 : Synchronization processes, e.g. processing of PCR [Program Clock References] arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18
• CPC Class Codes: H04N 21/435 : Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream
• CPC Class Codes: H04N 7/173 : with two-way working, e.g. subscriber sending a programme selection signal

Abstract

A system, method, apparatus and computer code are provided for producing coherent symbols from digital RF transmitters. A multiplexer receives a digital signal containing content data to be broadcast from the digital RF transmitters and inserts a first initialization packet into the digital signal, where the initialization packets implicit position in the digital signal will signal data framing in the digital RF transmitters. Where the initialization packet contains stuff bytes for deterministically initializing Trellis coders in the digital RF transmitters. A transport stream emitter transmits the digital signal to the plurality of digital RF transmitters.

Claims

1. A method for producing a plurality of coherent symbols from a plurality of digital RF transmitters having a plurality of Trellis coders, comprising the steps of:

receiving a digital signal containing content data to be broadcast from the plurality of digital RF transmitters;

inserting an initialization packet into the digital signal, the initialization packet containing a plurality of stuff bytes positioned in predetermined byte positions, respectively, setting each one of the plurality of Trellis coders to a predetermined state as a corresponding stuff byte enters; and

transmitting the digital signal containing the initialization packet to the plurality of digital RF transmitters.

2. The method according to claim 1, further comprising the steps of:

counting a predetermined number of packets from the initialization packet; and

inserting another initialization packet into the digital signal after the predetermined number of packets.

3. The method of claim 1, wherein the digital signal is a transport stream.

4. The method of claim 1, further comprising the step of:

error-correction coding the initialization packet.

5. The method of claim 1, further comprising the steps of:

generating a synchronization timestamp based from a common timebase;

storing the value of the synchronization timestamp into a synchronization time stamp field in the initialization packet;

storing a predetermined maximum delay value into a maximum delay field in the initialization packet;

generating an offset delay value respectively for each one of the plurality of RF transmitters;

storing the offset delay value into a transmitter time offset field in the initialization packet; and

storing a transmitter address corresponding to the offset delay into a transmitter address field in the initialization packet.

6. The method according to claim 5, wherein the common timebase is the global positional system (GPS).

7. The method according to claim 1, further comprising the step of:

storing a mapping of an interleaver; and

placing the plurality stuff bytes in the initialization packet in accordance with the mapping.

8. The method of claim 1, further comprising the step of:

locking a symbol clock and a carrier frequency of a modulator of the plurality of digital RF transmitters to a common timebase.

9. The method of claim 8, further comprising the step of:

locking the digital signal to the common timebase.

10. The method according to claim 9, wherein the common timebase is the global positional system (GPS).

11. The method of claim 1, wherein the digital RF transmitters include at least one of an eight-level vestigial sideband (8-VSB) modulator and an eight-level Trellis vestigial sideband (8T-VSB) modulator, and a power amplifier.

12. The method of claim 1, further comprising the step of:

synchronizing a plurality of data frames based on the arrival of the initialization packet.

13. The method of claim 1, further comprising the step of:

slaving a plurality of data frames to be broadcasted from the plurality of digital RF transmitters based on reception of the initialization packet.

14. The method of claim 1, further comprising the step of:

calculating a delay metric corresponding to a synchronization timestamp, a maximum delay value, and an offset delay value in the initialization packet, and a common timebase, wherein the synchronization timestamp is a value of the common timebase observed when the initialization packet is transmitted into a distribution network, wherein the maximum delay value corresponds to a delay in a distribution network, and the offset delay value corresponds to a delay value addressed to a respective one of the plurality of digital RF transmitters.

15. The method according to claim 14, wherein the common timebase is the global positional system (GPS).

16. The method of claim 1, further comprising the step of:

delaying the digital signal from being transmitted by the plurality of RF transmitters by a predetermined delay.

17. The method of claim 16, wherein the predetermined delay is greater than the longest delay path in a distribution network to the plurality of digital RF transmitters.

18. An apparatus for producing one or more initialization packets, comprising:

a receiver operable to receive a digital signal containing content data to be broadcast from a plurality of digital RF transmitters;

a packet inserter operable to insert an initialization packet into the digital signal, the initialization packet containing a plurality of stuff bytes positioned in predetermined byte positions, respectively, setting each one of the plurality of Trellis coders to a predetermined state as a corresponding stuff byte enters; and

a transmitter operable to transmit the digital signal to the plurality of digital RF transmitters.

19. The apparatus according to claim 18, further comprising:

a counter operable to count a predetermined number of packets from the initialization packet, and

wherein the packet inserter is further operable to insert another initialization packet into the digital signal after the predetermined number of packets.

20. The apparatus of claim 18, wherein the digital signal is a transport stream.

21. The apparatus of claim 18, further comprising:

an encoding unit operable to error-correction code the initialization packet.

22. The apparatus of claim 18, further comprising:

a common timebase operable to generate a synchronization timestamp, wherein the packet inserter is further operable to insert the value of the synchronization timestamp into a synchronization time stamp field in the initialization packet and store a predetermined maximum delay value into a maximum delay field in the initialization packet;

a delay unit operable to generate an offset delay value respectively for each one of the plurality of RF transmitters, wherein said inserter is further operable to store the offset delay value into a transmitter time offset field in the initialization packet and store a transmitter address corresponding to the offset delay into a transmitter address field in the initialization packet.

23. The apparatus according to claim 22, wherein the common timebase is the global positional system (GPS).

24. The apparatus according to claim 18, further comprising:

a memory for storing a mapping of an interleaver; and

a packet generator operable to place the stuff bytes in the initialization packet in accordance with the mapping.

25. The apparatus of claim 18, further comprising:

a timing unit operable to lock a symbol clock and a carrier frequency of a modulator of the plurality of digital RF transmitters to a common timebase.

26. The apparatus of claim 25, wherein the timing unit is further operable to lock the digital signal to the common timebase.

27. The apparatus according to claim 26, wherein the common timebase is the global positional system (GPS).

28. The apparatus of claim 18, wherein the digital RF transmitters include at least one of an eight-level vestigial sideband (8-VSB) modulator and an eight-level Trellis vestigial sideband (8T-VSB) modulator, and a power amplifier.

29. The apparatus of claim 18, further comprising:

a synchronizer operable to synchronize a plurality of data frames based on the arrival of the initialization packet.

30. The apparatus of claim 18, wherein a plurality of data frames are slaved to be broadcasted from the plurality of digital RF transmitters based on reception of the initialization packet.

31. The apparatus of claim 18, further comprising:

a delay unit operable to calculate a delay metric corresponding to a synchronization timestamp, a maximum delay value, and an offset delay value in the initialization packet, and a common timebase, wherein the synchronization timestamp is a value of the common timebase observed when the initialization packet is transmitted into a distribution network, wherein the maximum delay value corresponds to a delay in a distribution network, and the offset delay value corresponds to a delay value addressed to a respective one of the plurality of digital RF transmitters.

32. The apparatus according to claim 31, wherein the common timebase is the global positional system (GPS).

33. The apparatus of claim 18, further comprising:

a delay unit operable to delay the digital signal from being transmitted by the plurality of RF transmitters by a predetermined delay.

34. The apparatus of claim 33, wherein the predetermined delay is greater than the longest delay path in a distribution network to the plurality of digital RF transmitters.

35. A computer program product comprising a non-transitory computer readable medium having control logic stored therein for causing a computer to produce a plurality of coherent symbols from a plurality of digital RF transmitters having a plurality of Trellis coders, said control logic comprising:

computer readable program code means for causing the computer to receive a digital signal containing content data to be broadcast from the plurality of digital RF transmitters;

computer readable program code means for causing the computer to insert an initialization packet into the digital signal, the initialization packet containing a plurality of stuff bytes positioned in predetermined byte positions, respectively, for setting each one of the plurality of Trellis coders to a predetermined state as a corresponding stuff byte enters; and

computer readable program code means for causing the computer to transmit the digital signal to the plurality of digital RF transmitters.

36. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to count a predetermined number of packets from the initialization packet; and

computer readable program code means for causing the computer to inserting another initialization packet into the digital signal after the predetermined number of packets.

37. The computer program product of claim 35, wherein the digital signal is a transport stream.

38. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to error-correction code the initialization packet.

39. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to generate a synchronization timestamp based from a common timebase;

computer readable program code means for causing the computer to store the value of the synchronization timestamp into a synchronization time stamp field in the initialization packet;

computer readable program code means for causing the computer to store a predetermined maximum delay value into a maximum delay field in the initialization packet;

computer readable program code means for causing the computer to generate an offset delay value respectively for each one of the plurality of RF transmitters;

computer readable program code means for causing the computer to store the offset delay value into a transmitter time offset field in the initialization packet; and

computer readable program code means for causing the computer to store a transmitter address corresponding to the offset delay into a transmitter address field in the initialization packet.

40. The computer program product of claim 39, wherein the common timebase is the global positional system (GPS).

41. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to store a mapping of an interleaver; and

computer readable program code means for causing the computer to place the plurality stuff bytes in the initialization packet in accordance with the mapping.

42. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to lock a symbol clock and a carrier frequency of a modulator of the plurality of digital RF transmitters to a common timebase.

43. The computer program product of claim 42, further comprising:

computer readable program code means for causing the computer to lock the digital signal to the common timebase.

44. The computer program product of claim 43, wherein the common timebase is the global positional system (GPS).

45. The computer program product of claim 35, wherein the digital RF transmitters include at least one of an eight-level vestigial sideband (8-VSB) modulator and an eight-level Trellis vestigial sideband (8T-VSB) modulator, and a power amplifier.

46. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to synchronize a plurality of data frames based on the arrival of the initialization packet.

47. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to slave a plurality of data frames to be broadcasted from the plurality of digital RF transmitters based on reception of the initialization packet.

48. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to calculate a delay metric corresponding to a synchronization timestamp, a maximum delay value, and an offset delay value in the initialization packet, and a common timebase, wherein the synchronization timestamp is a value of the common timebase observed when the initialization packet is transmitted into a distribution network, wherein the maximum delay value corresponds to a delay in a distribution network, and the offset delay value corresponds to a delay value addressed to a respective one of the plurality of digital RF transmitters.

49. The computer program product of claim 48, wherein the common timebase is the global positional system (GPS).

50. The computer program product of claim 35, further comprising:

computer readable program code means for causing the computer to delay the digital signal from being transmitted by the plurality of RF transmitters by a predetermined delay.

51. The computer program product of claim 50, wherein the predetermined delay is greater than the longest delay path in a distribution network to the plurality of digital RF transmitters.

52. A system for producing coherent symbols from a plurality of RF transmitters having a plurality of Trellis coders, comprising:

a distribution network;

a multiplexer operable to receive a digital signal and insert an initialization packet into the digital signal and to transmit the digital signal over a distribution network; and

a plurality of modulators operable to receive the digital signal from the distribution network and modulate the digital signal, and

wherein the initialization packet contains a plurality of stuff bytes positioned in predetermined byte positions, respectively, setting each one of a plurality of Trellis coders in the plurality of modulators to a predetermined state as a corresponding stuff byte enters.

53. The system according to claim 52, wherein the multiplexer is further operable to count a predetermined number of packets from the initialization packet, and insert another initialization packet into the digital signal after the predetermined number of packets.

54. The system of claim 52, wherein the digital signal is a transport stream.

55. The system of claim 52, wherein the multiplexer is further operable to error-correction code the initialization packet.

56. The system of claim 52, further comprising:

a common timebase operable to generate a synchronization timestamp, wherein the multiplexer is further operable to insert the value of the synchronization timestamp into a synchronization time stamp field in the initialization packet and store a predetermined maximum delay value into a maximum delay field in the initialization packet, and

wherein the multiplexer is further operable to generate an offset delay value respectively for each one of the plurality of RF transmitters, wherein the multiplexer is further operable to store the offset delay value into a transmitter time offset field in the initialization packet and store a transmitter address corresponding to the offset delay into a transmitter address field in the initialization packet.

57. The system according to claim 56, wherein the common timebase is the global positional system (GPS).

58. The system according to claim 57, wherein the multiplexer is further operable to store a mapping of an interleaver and place the plurality stuff bytes in the initialization packet in accordance with the mapping.

59. The system of claim 52, wherein the modulator is further operable to lock a symbol clock and a carrier frequency of the modulator to a common timebase.

60. The system of claim 59, wherein the multiplexer and the modulator are operable to lock the digital signal to the common timebase.

61. The system according to claim 60, wherein the common timebase is the global positional system (GPS).

62. The system of claim 52, wherein the modulator is at least one of an eight-level vestigial sideband (8-VSB) modulator and an eight-level Trellis vestigial sideband (8T-VSB) modulator.

63. The system of claim 52, wherein the modulator is further operable to synchronize a plurality of data frames based on the arrival of the initialization packet.

64. The system of claim 52, wherein a plurality of data frames are slaved to be broadcasted from the plurality of digital RF transmitters based on reception of the initialization packet.

65. The system of claim 52, wherein the modulator is further operable to calculate a delay metric corresponding to a synchronization timestamp, a maximum delay value, and an offset delay value in the initialization packet, and a common timebase, wherein the synchronization timestamp is a value of the common timebase observed when the initialization packet is transmitted into a distribution network, wherein the maximum delay value corresponds to a delay in a distribution network, and the offset delay value corresponds to a delay value addressed to a respective one of the plurality of digital RF transmitters.

66. The system according to claim 65, wherein the common timebase is the global positional system (GPS).

67. The system of claim 52, wherein the modulator is further operable to delay the digital signal from being transmitted by the plurality of RF transmitters by a predetermined delay.

68. The system of claim 67, wherein the predetermined delay is greater than the longest delay path in a distribution network to the plurality of digital RF transmitters.

69. An apparatus for producing a plurality of coherent symbols from a plurality of digital RF transmitters having a plurality of Trellis coders, comprising:

means for receiving a digital signal containing content data to be broadcast from the plurality of digital RF transmitters;

means for inserting an initialization packet into the digital signal, the initialization packet containing a plurality of stuff bytes positioned in predetermined byte positions, respectively, setting each one of the plurality of Trellis coders to a predetermined state as a corresponding stuff byte enters; and

means for transmitting the digital signal to the plurality of digital RF transmitters.

70. The apparatus according to claim 69, further comprising:

means for counting a predetermined number of packets from the initialization packet; and

means for inserting another initialization packet into the digital signal after the predetermined number of packets.

71. The apparatus of claim 69, wherein the digital signal is a transport stream.

72. The apparatus of claim 69, further comprising:

means for error-correction coding the initialization packet.

73. The apparatus of claim 69, further comprising:

means for generating a synchronization timestamp based from a common timebase;

means for storing the value of the synchronization timestamp into a synchronization time stamp field in the initialization packet;

means for storing a predetermined maximum delay value into a maximum delay field in the initialization packet;

means for generating an offset delay value respectively for each one of the plurality of RF transmitters;

means for storing the offset delay value into a transmitter time offset field in the initialization packet; and

means for storing a transmitter address corresponding to the offset delay into a transmitter address field in the initialization packet.

74. The apparatus according to claim 69, further comprising:

means for storing a mapping of an interleaver; and

means for placing the plurality stuff bytes in the initialization packet in accordance with the mapping.

75. The apparatus of claim 69, further comprising:

means for locking a symbol clock and a carrier frequency of a modulator of the plurality of digital RF transmitters to a common timebase.

76. The apparatus of claim 75, further comprising:

means for locking the digital signal to the common timebase.

77. The apparatus of claim 69, further comprising:

means for synchronizing a plurality of data frames based on the arrival of the initialization packet.

78. The apparatus of claim 69, further comprising:

means for slaving a plurality of data frames to be broadcasted from the plurality of digital RF transmitters based on reception of the initialization packet.

79. The apparatus of claim 69, further comprising the step of:

means for calculating a delay metric corresponding to a synchronization timestamp, a maximum delay value, and an offset delay value in the initialization packet, and a common timebase, wherein the synchronization timestamp is a value of the common timebase observed when the initialization packet is transmitted into a distribution network, wherein the maximum delay value corresponds to a delay in a distribution network, and the offset delay value corresponds to a delay value addressed to a respective one of the plurality of digital RF transmitters.

80. The apparatus of claim 69, further comprising:

means for delaying the digital signal from being transmitted by the plurality of RF transmitters by a predetermined delay.