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

• US 7,532,677 B2
• Filed: 02/28/2006
• Issued: 05/12/2009
• 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): Torres; Juan A
• Application Number:
  US11/276,453
• Publication Number:
  US 20070223612A1
• Time in Patent Office: 1,169 Days
• Field of Search: 375/265, 375/354
• 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 receiver receives a first initialization packet containing a plurality of stuff bytes and Trellis coders are deterministically initialized using the first initialization packet.

Claims

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

receiving a first initialization packet containing a plurality of stuff bytes, each stuff byte positioned in a predetermined byte position, respectively; and

setting each one of the plurality of Trellis coders to a predetermined state as a corresponding stuff byte enters, thereby causing the plurality of digital RF transmitters to transmit a plurality of symbols coherently.

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

receiving another initialization packet after a multiple of a predetermined number of packets.

3. The method of claim 1, wherein the initialization packet is received from a transport stream.

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

error-correction decoding the initialization packet.

5. The method of claim 1, wherein the initialization packet further contains a synchronization timestamp based from a common timebase, a predetermined maximum delay value, an offset delay value, and a transmitter address corresponding to the offset delay.

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:

interleaving the initialization packet.

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

locking a symbol clock and a carrier frequency to a common timebase.

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

locking a digital signal comprising the initialization packet 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, further comprising the step of:

modulating a digital signal using at least one of an eight-level vestigial sideband (8-VSB) modulation and an eight-level Trellis vestigial sideband (8T-VSB) modulation.

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 an 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. A apparatus for producing a plurality of coherent symbols from a plurality of digital RF transmitters, comprising:

a packet receiver operable to receive a first initialization packet containing a plurality of stuff bytes, each stuff byte positioned in a predetermined byte position, respectively; and

a plurality of Trellis coders, each Trellis coder operable to set to a predetermined state as a corresponding stuff byte enters, thereby causing the plurality of digital RF transmitters to transmit a plurality of symbols coherently.

19. The apparatus according to claim 18, wherein the packet receiver is further operable to detect another initialization packet after a multiple of a predetermined number of packets.

20. The apparatus of claim 18, wherein the initialization packet is received from a transport stream.

21. The apparatus of claim 18, further comprising:

a decoder operable to error-correction decode the initialization packet.

22. The apparatus of claim 18, wherein the initialization packet further contains a synchronization timestamp based from a common timebase, a predetermined maximum delay value, an offset delay value, and a transmitter address corresponding to the offset delay.

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:

an interleave operable to interleave the initialization packet.

25. The apparatus of claim 18, further comprising:

a timing unit operable to lock a symbol clock and a carrier frequency to a common timebase.

26. The apparatus of claim 25, wherein the timing unit is further operable to lock a digital signal including the initialization packet 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, further comprising:

a signal processor operable to modulate a digital signal carrying the initialization packet using at least one of an eight-level vestigial sideband (8-VSB) modulation and an eight-level Trellis vestigial sideband (8T-VSB) modulation.

29. The apparatus of claim 18, further comprising:

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

30. The apparatus of claim 18, further comprising:

a controller operable to slave a plurality of data frames to be broadcasted from the plurality of digital RF transmitters based on reception of an initialization packet.

31. The apparatus of claim 18, further comprising:

a timing 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 timing 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-readable medium having stored thereon sequences of instructions, the sequences of instructions including instructions which when executed by a computer system causes the computer system to:

receive a first initialization packet containing a plurality of stuff bytes, each stuff byte positioned in a predetermined byte position, respectively; and

set each one of the plurality of Trellis coders to a predetermined state as a corresponding stuff byte enters, thereby causing the plurality of digital RF transmitters to transmit a plurality of symbols coherently.

36. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system to:

receive another initialization packet after a multiple of a predetermined number of packets.

37. The computer-readable medium of claim 35, wherein the initialization packet is received from a transport stream.

38. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system to:

error-correction decode the initialization packet.

39. The computer-readable medium of claim 35, wherein the initialization packet further contains a synchronization timestamp based from a common timebase, a predetermined maximum delay value, an offset delay value, and a transmitter address corresponding to the offset delay.

40. The computer-readable medium of claim 39, wherein the common timebase is the global positional system (GPS).

41. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system to:

interleave the initialization packet.

42. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system to:

lock a symbol clock and a carrier frequency to a common timebase.

43. The computer-readable medium of claim 42, further including instructions which when executed by a computer system causes the computer system to:

lock a digital signal comprising the initialization packet to the common timebase.

44. The computer-readable medium of claim 43, wherein the common timebase is the global positional system (GPS).

45. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system to:

modulate a digital signal carrying the initialization packet using at least one of an eight-level vestigial sideband (8-VSB) modulation and an eight-level Trellis vestigial sideband (8T-VSB) modulation.

46. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system to:

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

47. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system to:

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

48. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system 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-readable medium of claim 48, wherein the common timebase is the global positional system (GPS).

50. The computer-readable medium of claim 35, further including instructions which when executed by a computer system causes the computer system to:

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-readable medium 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. An apparatus for producing a plurality of coherent symbols from a plurality of digital RF transmitters, each of the plurality of digital RF transmitters having a plurality of Trellis coders, comprising:

means for receiving a first initialization packet containing a plurality of stuff bytes, each stuff byte positioned in a predetermined byte position, respectively; and

means for setting each one of the plurality of Trellis coders to a predetermined state as a corresponding stuff byte enters, thereby causing the plurality of digital RF transmitters to transmit a plurality of symbols coherently.

53. The apparatus according to claim 52, further comprising:

means for receiving another initialization packet after a multiple of a predetermined number of packets.

54. The apparatus of claim 52, wherein the initialization packet is received from a transport stream.

55. The apparatus of claim 52, further comprising:

means for error-correction decoding the initialization packet.

56. The apparatus of claim 52, wherein the initialization packet further contains a synchronization timestamp based from a common timebase, a predetermined maximum delay value, an offset delay value, and a transmitter address corresponding to the offset delay.

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

58. The apparatus according to claim 52, further comprising:

means for interleaving the initialization packet.

59. The apparatus of claim 52, further comprising:

means for locking a symbol clock and a carrier frequency to a common timebase.

60. The apparatus of claim 59, further comprising:

means for locking a digital signal comprising the initialization packet to the common timebase.

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

62. The apparatus of claim 52, further comprising:

means for modulating a digital signal using at least one of an eight-level vestigial sideband (8-VSB) modulation and an eight-level Trellis vestigial sideband (8T-VSB) modulation.

63. The apparatus of claim 52, further comprising:

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

64. The apparatus of claim 52, further comprising:

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

65. The apparatus of claim 52, further comprising:

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.

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

67. The apparatus of claim 52, further comprising:

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

68. The apparatus 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. A system for producing a plurality of coherent symbols from a plurality of digital RF transmitters, comprising:

a multiplexer operable to receive a digital signal containing content data to be broadcast from the plurality of digital RF transmitters and to insert a first initialization packet into the digital signal, the first initialization packet containing a plurality of stuff bytes, each stuff byte positioned in a predetermined byte position, respectively, and to transmit the digital signal to the plurality of digital RF transmitters; and

a modulator having a plurality of Trellis coders, the modulator operable to receive the digital signal, extract the first initialization packet and to set each one of the plurality of Trellis coders to a predetermined state as a corresponding stuff byte enters, thereby causing the plurality of digital RF transmitters to transmit a plurality of symbols coherently.

70. The system of claim 69, wherein the multiplexer is further operable to generate another initialization packet after a multiple of a predetermined number of packets.

71. The system of claim 69, wherein the multiplexer transmits the digital signal to the modulator in over a distribution network.

72. The system of claim 69, the multiplexer further comprising an encoder operable to error-correction encode the initialization packet and the modulator further comprising a decoder operable to error-correction decode the initialization packet.

73. The system of claim 69, wherein the initialization packet further contains a synchronization timestamp based from a common timebase, a predetermined maximum delay value, an offset delay value, and a transmitter address corresponding to the offset delay.

74. The system according to claim 73, wherein the common timebase is the global positional system (GPS).

75. The system according to claim 69, the modulator further comprising:

an interleave operable to interleave the initialization packet

76. The system of claim 69, further comprising:

a timing unit operable to lock a symbol clock and a carrier frequency to a common timebase.

77. The system of claim 76, wherein

the timing unit is further operable to lock a digital signal including the initialization packet to the common timebase.

78. The system according to claim 77, wherein the common timebase is the global positional system (GPS).

79. The system of claim 69, wherein the modulator is further operable to modulate a digital signal carrying the initialization packet using at least one of an eight-level vestigial sideband (8-VSB) modulation and an eight-level Trellis vestigial sideband (8T-VSB) modulation.

80. The system of claim 69, the modulator further comprising:

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

81. The system of claim 69, the modulator further comprising:

a controller operable to slave a plurality of data frames to be broadcasted from the plurality of digital RF transmitters based on reception of an initialization packet.

82. The system of claim 69, further comprising:

a timing 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.

83. The system according to claim 82, wherein the common timebase is the global positional system (GPS).

84. The system of claim 69, further comprising:

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

85. The system of claim 84, wherein the predetermined delay is greater than the longest delay path in a distribution network to the plurality of digital RF transmitters.