Methods and apparatuses for minimizing co-channel interference

• US 20050226414A1
• Filed: 04/11/2005
• Published: 10/13/2005
• Est. Priority Date: 04/12/2004
• Status: Active Grant

• Current Assignee: DTVG Licensing, Inc. (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Sun, Feng-Wen, Santoru, Joseph, Lee, Lin-Nan, Maitra, Shamik, Chen, Ernest C., Lin, Tung-Sheng, Lai, Dennis, Ancken, Adam Von, Zhou, Guangcai
• Granted Patent: US 7,460,832 B2
• Time in Patent Office: Days
• US Class Current: 380/210
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/1858 Arrangements for data transmission on the physical system, i.e. for data bit transmission between network components
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/6143 involving transmission via a satellite
• CPC Class Codes: H04N 5/211 Ghost signal cancellation H04N23/81 takes precedence
• CPC Class Codes: H04N 7/16 Analogue secrecy systems; Analogue subscription systems
• CPC Class Codes: H04N 7/163 by receiver means only
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests

Abstract

Methods and apparatuses for minimizing co-channel interference in communications systems are disclosed. A method in accordance with the present invention comprises scrambling a first frame using a first scrambling code, attaching a first header to the first frame to create the first signal, scrambling a second frame using a second scrambling code, attaching a second header to the second frame to create the second signal, and transmitting the first signal and the second signal over different channels of the communication system.

Claims

1. A method for minimizing co-channel interference in a communication system having at least a first signal and a second signal, each signal transmitted on different channels within the communication system, comprising:

scrambling a first frame using a first scrambling code;

attaching a first header to the first frame to create the first signal;

scrambling a second frame using a second scrambling code;

attaching a second header to the second frame to create the second signal; and

transmitting the first signal and the second signal over different channels of the communication system.

2. The method of claim 1, wherein the first header is attached to the first frame prior to using the first scrambling code.

3. The method of claim 2, wherein the second header is attached to the second frame after scrambling the second frame using the second scrambling code.

4. The method of claim 1, further comprising:

scrambling the first header using a third scrambling code; and

scrambling the second header using a fourth scrambling code.

5. The method of claim 4, wherein the first scrambling code and the second scrambling code are Gold codes.

6. The method of claim 5, wherein the third scrambling code and the fourth scrambling code are selected from a limited number of codes.

7. The method of claim 1, wherein the first header contains a first Start-Of-Frame (SOF) portion and the second header contains a second SOF portion different than the first SOF portion.

9. The method of claim 1, wherein the first frame comprises a number of first pilot symbol blocks and the second frame comprises a number of second pilot symbol blocks.

10. The method of claim 9, wherein the first pilot symbol blocks are scrambled with the header.

11. The method of claim 1, wherein the first scrambling code is generated from a first seed and the second scrambling code is generated from a second seed, the first seed and the second seed being selected from a limited number of seeds.

12. The method of claim 11, wherein a number of seeds is determined based on a number of interfering channels within the communication system.

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

transmitting information associated with the first scrambling code and the second scrambling code to a receiver within the communication system.

14. A computer-readable medium bearing instructions for minimizing co-channel interference in a communication system, said instruction, being arranged, upon execution, to cause one or more processors to perform the method of claim 1.

8. The method of claim 8, wherein the first SOF portion and the second SOF portion are selected from a limited number of SOF portions.

15. An apparatus for minimizing co-channel interference in a communication system having at least a first signal and a second signal, each signal transmitted on different channels within the communication system, comprising:

a scrambler for scrambling at least a first data frame of the first signal using a first scrambling code and for scrambling at least a second data frame of the second signal using a second scrambling code; and

a transmitter for transmitting the first signal and the second signal over different channels of the communication system.

16. The apparatus of claim 15, wherein the first signal further comprises a first header and the second signal further comprises a second header, and the first header and the second header are also scrambled by the scrambler.

17. The apparatus of claim 16, wherein the first header is scrambled using a third scrambling code and the second header is scrambled using a fourth scrambling code.

18. The apparatus of claim 17, wherein the third scrambling code and the fourth scrambling code are selected from a limited number of scrambling codes.

19. The apparatus of claim 15, wherein the first header contains a first Start-Of-Frame (SOF) portion and the second header contains a second SOF portion different than the first SOF portion.

20. The apparatus of claim 19, wherein the first SOF portion and the second SOF portion are selected from a limited number of SOF portions.