Method and system for undersampled symbol synchronization

• US 20060078077A1
• Filed: 11/21/2005
• Published: 04/13/2006
• Est. Priority Date: 10/26/2001
• Status: Abandoned Application

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Karr, Lawrence J.
• Application Number:
  US11/284,295
• Publication Number:
  US 20060078077A1
• Time in Patent Office: Days
• US Class Current: 375/367
• CPC Class Codes: H04H 20/34 using an out-of-band subcarrier signal
• CPC Class Codes: H04H 20/72 of terrestrial networks
• CPC Class Codes: H04H 40/27 specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
• CPC Class Codes: H04H 60/92 for local area
• CPC Class Codes: H04L 7/041 using special codes as synchronising signal
• CPC Class Codes: H04L 7/043 Pseudo-noise [PN] codes variable during transmission synchronisation of spread spectrum receivers H04B1/69
• CPC Class Codes: H04L 7/06 the synchronisation signals differing from the information signals in amplitude, polarity or frequency or length

Abstract

Described is a system and method for providing a synchronization pattern in a communication system. The method includes generating a synchronization pattern with good randomness properties; packing a signal for transmission with m headers, each header consisting of the synchronization pattern 1/m symbol-time shifted from the previous header; and transmitting the signal. A further method provides for the sampling the transmitted signal with m headers of symbol-time shifted synchronization patterns; and determining symbol timing offset by computing and reordering correlation peaks from the synchronization patterns. A system includes a transmitting system, a receiving system, and a data channel. The transmitted signal includes m headers with 1/m symbol-time shifted synchronization patterns. The receiving system undersamples the transmitted signal with m synchronization patterns to simulate an oversampled synchronization pattern.

Claims

1-35. -35. (canceled)

36. A computer-implemented method for providing a synchronization pattern for use in a communications system, the method comprising:

generating a plurality of synchronization patterns, wherein each of the plurality of synchronization patterns differ from the other synchronization patterns by a time shift that is a multiple of a fraction of a symbol time;

encoding an information signal with a plurality of headers, each header comprising one of the plurality of synchronization patterns such that the multiple of the fraction of the symbol time is not a whole number; and

transmitting the encoded information signal over a communications system.

37. The method of claim 36, wherein each of the plurality of synchronization patterns differs from the other synchronization patterns by a multiple of 1/m of the symbol time, and wherein there are m headers, m is any positive, non-zero integer, and the multiple of 1/m of is not a whole number.

38. The method of claim 36, wherein each of the plurality of synchronization patterns differs by the other synchronization patterns by a multiple of 1/m of the symbol time, and wherein there are n headers, and m and n are any positive, non-zero integers such that m is not equal to n.

39. The method of claim 36, wherein the synchronization pattern is at least one of a random sequence, a pseudo-random sequence, and a periodic sequence.

40. The method of claim 36, wherein the synchronization pattern further comprises a maximal-length sequence of length 15 generated by a 4-bit linear feedback shift register.

41. The method of claim 36, wherein the synchronization pattern is a periodic sequence that is uniquely identifiable from the information signal.

42. A system for providing a synchronization pattern in digital communications, the system comprising:

a transmitter configured to;

generate a plurality of synchronization patterns, wherein each of the plurality of synchronization patterns differ from the other synchronization patterns by a time shift that is a multiple of a fraction of a symbol time;

encode an information signal with a plurality of headers, each header comprising one of the plurality of synchronization patterns such that the multiple of the fraction of the symbol time is not a whole number; and

transmit the encoded information signal over a communications system; and

a transmit medium configured to provide the transmitted information signal to a receiver.

43. The system of claim 42, wherein each of the plurality of synchronization patterns differs from the other synchronization patterns by a multiple of 1/m of the symbol time, and wherein there are m headers, m is any positive, non-zero integer, and the multiple of 1/m of is not a whole number.

44. The system of claim 42, wherein each of the plurality of synchronization patterns differs by the other synchronization patterns by a multiple of 1/m of the symbol time, and wherein there are n headers, and m and n are any positive, non-zero integers such that m is not equal to n.

45. The system of claim 42, wherein the synchronization pattern is at least one of a random sequence, a pseudo-random sequence, and a periodic sequence.

46. The system of claim 42, wherein the synchronization pattern further comprises a maximal-length sequence of length 15 generated by a 4-bit linear feedback shift register.

47. The system of claim 42, wherein the synchronization pattern is a periodic sequence that is uniquely identifiable from the information signal.

48. The system of claim 42, wherein the receiver is implemented in a watch device.

49. A computer-readable medium having computer instructions for symbol synchronization in a communication system, the instructions comprising:

generating a synchronization pattern;

encoding m portions of an information signal with m headers to provide an encoded information signal, m being a positive integer and each header comprising the synchronization pattern, wherein after the first synchronization pattern, each synchronization pattern is shifted by a fraction of a symbol-time from the other synchronization patterns, and wherein the fraction of a symbol-time is 1/n, n being any positive, non-zero integer such that m is not equal to n; and

transmitting the encoded information signal over a communication medium.

50. The computer-readable medium of claim 49, wherein after the first synchronization pattern in the first header, each synchronization pattern is shifted by a multiple of 1/m of a symbol-time from the previous synchronization pattern.

51. The computer-readable medium of claim 50, wherein the first synchronization pattern in the first header includes zero time shift.

52. The computer-readable medium of claim 49, wherein the synchronization pattern is at least one of a random sequence, a pseudo random sequence, and a periodic sequence.

53. The computer-readable medium of claim 49, wherein the synchronization pattern is a periodic sequence that is uniquely identifiable from the information signal.

54. The method of claim 49, wherein the synchronization pattern further comprises a maximal-length sequence of length 15 generated by a 4-bit linear feedback shift register.

55. The computer-readable medium of claim 49, wherein the information signal is encoded with the headers such that synchronization at a receiver is accomplished by generating a correlation peak for each of the m transmitted synchronization patterns using substantially the same synchronization patterns.