Method and apparatus for minimizing co-channel interference by scrambling

• US 20050286405A1
• Filed: 12/10/2004
• Published: 12/29/2005
• Est. Priority Date: 06/28/2004
• Status: Active Grant

• Current Assignee: DTVG Licensing, Inc. (AT&T, Inc.)
• Original Assignee: DTVG Licensing, Inc. (AT&T, Inc.)
• Inventors: Sun, Feng-Wen, Iyer, Lakshmi
• Granted Patent: US 7,672,285 B2
• Time in Patent Office: Days
• US Class Current: 370/208
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• 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: H04J 13/102 Combining codes
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04W 72/0466 the resource being a scrambling code
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

An approach is provided for minimizing co-channel interference in a communication system is disclosed. Non-header portions of frames, which are transmitted over the communication system, are scrambled according to respective different scrambling sequences. The above arrangement is particularly suited to a digital satellite broadcast and interactive system.

Claims

1. A method of minimizing co-channel interference in a communication system, the method comprising the steps of:

assigning a first scrambling sequence, associated with a header or a pilot sequence of a first

assigning a second scrambling sequence, associated with a header or a pilot sequence of a second frame, to a second co-channel that is adjacent to the first co-channel,

wherein non-header portions of the frames are scrambled according to the respective different scrambling sequences.

2. A method according to claim 1, wherein the scrambling sequences are based on Gold sequences with correspondingly different seeds.

3. A method according to claim 2, wherein the co-channels are among 17 co-channels, the seeds corresponding to the 17 co-channels are specified by Table A or Table B:

4. A method according to claim 2, further comprising the step of:

determining the seeds to minimize a worst cross-correlation condition.

5. A method according to claim 1, wherein the communication system includes a satellite supporting digital broadcast and interactive applications.

6. A method according to claim 1, wherein the header or the pilot sequence is used for acquiring or tracking carrier phase and carrier frequency.

7. A method according to claim 1, wherein the header and the pilot sequence is used for acquiring or tracking carrier phase and carrier frequency.

8. A method according to claim 1, further comprising the step of:

transmitting the frame according to a modulation scheme including Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), 8PSK, 16 Amplitude Phase Shift Keying (APSK), 32APSK, or a high order Quadrature Amplitude Modulation (QAM).

9. A method according to claim 1, further comprising the step of:

modulating the frames according to different modulation schemes.

10. A method according to claim 1, wherein each of the frames includes information encoded according to Low Density Parity Check (LDPC) coding.

11. 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.

12. An apparatus for minimizing co-channel interference in a communication system, comprising:

a scrambler configured to assign a first scrambling sequence, associated with a header or a pilot sequence of a first frame, to a first co-channel,

wherein the scrambler assigns a second scrambling sequence, associated with a header or a pilot sequence of a second frame, to a second co-channel that is adjacent to the first co-channel,

wherein non-header portions of the frames are scrambled according to the respective scrambling sequences.

13. An apparatus according to claim 12, wherein the scrambling sequences are based on Gold sequences with different seeds.

14. An apparatus according to claim 13, wherein the co-channels are among 17 co-channels, the seeds corresponding to 17 co-channels are specified by Table A or Table B:

15. An apparatus according to claim 13, further comprising:

means for determining the seeds to minimize a worst cross-correlation condition.

16. An apparatus according to claim 12, wherein the communication system includes a satellite supporting digital broadcast and interactive applications.

17. An apparatus according to claim 12, wherein the header or the pilot sequence is used for acquiring or tracking carrier phase and carrier frequency.

18. An apparatus according to claim 12, wherein the header and the pilot sequence is used for acquiring or tracking carrier phase and carrier frequency.

19. An apparatus according to claim 12, further comprising:

a transmitter configured to transmit the frame according to a modulation scheme including Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), 8PSK, 16 Amplitude Phase Shift Keying (APSK), 32APSK, or a high order Quadrature Amplitude Modulation (QAM).

20. An apparatus according to claim 12, further comprising:

a modulator configured to modulate the frames according to different modulation schemes.

21. An apparatus according to claim 12, wherein each of the frames includes information encoded according to Low Density Parity Check (LDPC) coding.

22. A method for communicating in a radio communication system, the method comprising the steps of:

transmitting a plurality of frames over different communication channels established over the radio communication system, the communication channels being adjacent co-channels,

wherein each of the frames includes a header and a pilot sequence for synchronization of carrier phase and carrier frequency, and non-header portions of the frames are scrambled according to respective different scrambling sequences to minimize interference between the co-channels.

23. A method according to claim 22, wherein each of the frames has a structure according to a Digital Video Broadcast (DVB) standard.

24. An apparatus for communicating in a radio communication system, comprising:

a transmitter configured to transmit a plurality of frames over different communication channels established over the radio communication system, wherein the communication channels are adjacent co-channels,

wherein each of the frames includes a header and a pilot sequence for synchronization of carrier phase and carrier frequency, and non-header portions of the frames are scrambled according to respective different scrambling sequences to minimize interference between the co-channels.

25. A transmitter according to claim 24, wherein each of the frames has a structure according to a Digital Video Broadcast (DVB) standard.

26. A method for communicating in a radio communication system, the method comprising the steps of:

receiving a plurality of frames over different communication channels established over the radio communication system, the communication channels being adjacent co-channels,

wherein each of the frames includes a header and a pilot sequence for synchronization of carrier phase and carrier frequency, and non-header portions of the frames are scrambled according to respective different scrambling sequences to minimize interference between the co-channels.

27. A method according to claim 26, wherein each of the frames has a structure according to a Digital Video Broadcast (DVB) standard.

28. An apparatus for communicating in a radio communication system, comprising:

a receiver configured to receive a plurality of frames over different communication channels established over the radio communication system, wherein the communication channels are adjacent co-channels,

wherein each of the frames includes a header and a pilot sequence for synchronization of carrier phase and carrier frequency, and non-header portions of the frames are scrambled according to respective different scrambling sequences to minimize interference between the co-channels.

29. An apparatus according to claim 28, wherein each of the frames has a structure according to a Digital Video Broadcast (DVB) standard.