METHOD AND APPARATUS FOR PROCESSING TIMESTAMP USING SIGNATURE INFORMATION ON PHYSICAL LAYER

• US 20100223399A1
• Filed: 12/11/2009
• Published: 09/02/2010
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute, Korea Advanced Institute of Science and Technology
• Original Assignee: Electronics and Telecommunications Research Institute, Korea Advanced Institute of Science and Technology
• Inventors: LEE, Kyu-sang, SUNG, Ji-hoon, RHEE, June-koo, KO, Je-soo, LEE, Chan-kyun, KIM, Seung-hwan
• Granted Patent: US 8,635,371 B2
• Time in Patent Office: Days
• US Class Current: 709/248
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864

Abstract

A method and apparatus for processing a timestamp using signature information on a physical layer is provided. The timestamp processing terminal uses a pseudo-random binary sequence to assign signature information to a message which is to be sent to another terminal, and verifies the signature information on a physical layer. The signature information is used to identify the message as a sync message. Accordingly, it is possible to precisely process the timestamp.

Claims

1. A timestamp processing terminal for performing synchronization with another terminal connected to a network, comprising:

a first timestamp processing unit configured to assign signature information to a message, which is to be sent to the terminal, using a pseudo-random binary sequence (PRBS) and to verify the signature information on a physical layer, wherein the signature information is used to identify the message as a sync message; and

a second timestamp processing unit configured to identify if a message received from the terminal is a sync message by verifying on the physical layer if the PRBS is included in the message.

2. The timestamp processing terminal of claim 1, wherein the first timestamp processing unit comprises:

a PRBS generator configured to generate the PRBS;

a signature information assigning unit configured to generate signature information including the PRBS and to assign the signature information to a sync message; and

a PRBS verifying unit configured to verify on the physical layer if a bitstream received from an upper layer includes the PRBS and, if the bitstream is verified as including the PRBS, to determine the bitstream as the sync message and perform timestamping.

3. The timestamp processing terminal of claim 2, wherein the PRBS generator enters a predetermined input bit in a prime polynomial to generate the PRBS.

4. The timestamp processing terminal of claim 3, wherein the PRBS generator generates the PRBS by performing exclusive-or (XOR) operation on the prime polynomial using a linear feedback shift register (LFSR).

5. The timestamp processing terminal of claim 3, wherein the PRBS generator enters the input bit in the prime polynomial with reference to a mapping table where the input bit and a sequence identifier of a sync message are mapped.

6. The timestamp processing terminal of claim 2, wherein the signature information assigning unit assigns the signature information to a TLV field indicating type, length and value of the sync message.

7. The timestamp processing terminal of claim 2, wherein the signature information assigning unit generates the signature information by adding the PRBS following a predetermined input bit.

8. The timestamp processing terminal of claim 2, wherein the PRBS verifying unit verifies the PRBS using a prime polynomial.

9. The timestamp processing terminal of claim 8, wherein the PRBS verifying unit performs exclusive-or (XOR) operation on an LFSR and verifies the PRBS using the XOR result and an output value.

10. The timestamp processing terminal of claim 9, wherein the PRBS verifying unit determines the bitstream as a sync message if bit ‘

0’

is consecutively generated a predetermined times as a detected result value upon the verification.

11. The timestamp processing terminal of claim 2, further comprising a post-PRBS verifying unit configured to verify on an upper layer if the PRBS of the signature information is an input bit transmitted from the upper layer to the physical layer.

12. The timestamp processing terminal of claim 1, wherein the second timestamp processing unit comprises:

a PRBS identifier configured to identify if a message received from the terminal is a sync message by verifying on the physical layer if the PRBS is included in the message; and

a synchronizing unit configured to perform synchronization using a timestamp which is stored if the message has been identified as the sync message.

13. The timestamp processing terminal of claim 12, wherein the PRBS identifier identifies the PRBS using a prime polynomial.

14. A timestamp processing method for performing synchronization with another terminal connected to a network, comprising:

generating a pseudo-random binary sequence (PRBS);

assigning signature information to a message, which is to be sent to the terminal, using the PRBS, wherein the signature information is used to identify the message as a sync message; and

verifying the signature information on a physical layer.

15. The timestamp processing method of claim 14, wherein generating the PRBS comprises:

providing a predetermined input bit with reference to a mapping table where the input bit and a sequence identifier of a sync message are mapped; and

generating the PRBS by performing exclusive-or (XOR) operation on prime polynomials on the basis of the input bit.

16. The timestamp processing method of claim 14, wherein assigning the signature information comprises:

generating the signature information by adding the PRBS following a predetermined input bit; and

assigning the signature information to a TLV field indicating type, length and value of the sync message.

17. The timestamp processing method of claim 14, wherein verifying the signature information comprises verifying through a prime polynomial on the physical layer if a bitstream received from an upper layer includes the PRBS and, if the bitstream is verified as including the PRBS, determining the bitstream as the sync message.

18. The timestamp processing method of claim 14, further comprising:

verifying on an upper layer if the PRBS of the signature information is an input bit transmitted from the upper layer to the physical layer; and

if the PRBS is verified as the input bit, providing a sync message including a sequence identifier mapped to the input bit to the terminal.

19. An information storage medium for recording a hierarchical structure of a timestamp processing terminal for performing synchronization with another terminal connected to a network, comprising:

an application layer including a first application layer and a second application layer, wherein the first application layer is configured to generate a pseudo-random binary sequence (PRBS), to assign signature information to a message, which is to be sent to the terminal, using the PRBS, the signature information being used to identify the message as a sync message, and to transmit the message to a lower layer, and the second application layer is configured to perform synchronization if the verified PRBS is received from the lower layer; and

a physical layer including a first physical layer and a second physical layer, wherein the first physical layer is configured to verify if a bitstream received from the first application layer includes the PRBS and, if the bitstream is verified as including the PRBS, to determine the bitstream as the sync message and perform timestamping, and the second physical layer is configured to identify if a message received from the terminal is a sync message by verifying if the PRBS is included in the message and to perform synchronization if the message has been identified as the sync message.

20. The information storage medium of claim 19, wherein the physical layer comprises a PRBS verifying layer to verify the PRBS.