Method and system for undersampled symbol synchronization

• US 6,999,545 B2
• Filed: 10/26/2001
• Issued: 02/14/2006
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Karr, Lawrence J.
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US10/044,306
• Publication Number:
  US 20030165206A1
• Time in Patent Office: 1,572 Days
• Field of Search: 375/368, 375/367, 375/369, 375/366, 370/514, 370/515, 370/513, 708/252
• 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. A method for symbol synchronization in a communication transmitter, the method comprising the steps of:

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.

2. The method of claim 1, 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.

3. The method of claim 1, wherein the synchronization pattern is at least one of a random sequence, a pseudo random sequence, and a periodic sequence.

4. The method of claim 1, wherein the synchronization pattern is a periodic sequence that is uniquely identifiable from the information signal.

5. The method of claim 1, wherein the synchronization pattern further comprises a maximal-length sequence of length 15 generated by a 4-bit linear feedback shift register.

6. A method for providing synchronization in a communication system, comprising:

generating a plurality of synchronization patterns, wherein each of the plurality of synchronization patterns differ from the other synchronization patterns by a multiple of 1/m of a symbol-time shift wherein the multiple of 1/m of the symbol-time shift is not a whole number;

encoding each portion of a n portions of an information signal with a header, each header comprising one of the plurality of synchronization patterns, wherein m and n are any positive, non-zero integers such that m is not equal to n; and

transmitting the encoded information signal over a communications system.

7. The method of claim 6, wherein the synchronization pattern is at least one of a random sequence, a pseudo-random sequence, and a periodic sequence.