Signal processing under attenuated transmission conditions

• US 20060041918A9
• Filed: 05/01/2003
• Published: 02/23/2006
• Est. Priority Date: 08/31/1999
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Kolze, Thomas J., Currivan, Bruce J., Howard, Daniel H., Ungerboeck, Gottfried
• Granted Patent: US 7,529,289 B2
• Time in Patent Office: Days
• US Class Current: 725/111
• CPC Class Codes: H04B 1/71 the interference being narrowband interference
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 7/216 Code division or spread-spectrum multiple access [CDMA, SSMA]
• CPC Class Codes: H04L 2025/03375 Passband transmission
• CPC Class Codes: H04L 2025/03477 not time-recursive
• CPC Class Codes: H04L 25/03038 with a non-recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/49 using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems spectral shaping H04L25/03828
• CPC Class Codes: H04L 27/3405 Modifications of the signal space to increase the efficiency of transmission, e.g. reduction of the bit error rate, bandwidth, or average power
• CPC Class Codes: H04L 27/3411 reducing the peak to average power ratio or the mean power of the constellation; Arrangements for increasing the shape gain of a signal set
• CPC Class Codes: H04N 21/42676 for modulating an analogue carrier signal to encode digital information or demodulating it to decode digital information, e.g. ADSL or cable modem
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

Signal processing under attenuated transmission conditions. Within an orthogonal signal space, the number of orthogonal signals that are used to transmit information from a transmitter to a receiver is reduced and the transmitted power of each of the now remaining orthogonal signals is modified; this may involve increasing the power of all of the remaining orthogonal signals equally or alternatively modifying them individually. The same modulation used before the reduction may also be used afterwards; within communication systems having multiple transmitter-receiver paths, this will ensure that the communication system'"'"'s throughput and efficiency will remain unchanged even when one (or more) transmitter-receiver paths are highly attenuated. In addition, robust mode operation is provided for ranging and registering of transmitter devices when entering the communication system. In addition, the unused orthogonal signals may be employed to support interference cancellation of those orthogonal signals that are used to transmit information.

Claims

1. A communication system that supports attenuated transmission adaptation, the system comprising:

a transmitting device that is operable to transmit information using a plurality of active codes, each active code of the plurality of active codes being transmitted using a first power per code;

a receiving device, communicatively coupled to the transmitting device via a communication channel, that is operable to receive transmitted information from the transmitting device;

wherein the receiving device instructs the transmitting device to transmit information using a plurality of permitted codes;

the receiving device instructs the transmitting device to transmit each permitted code of the plurality of permitted codes using a second power per code; and

the communication channel comprises a spectrum portion that is partitioned into a plurality of logical channels.

2. The system of claim 1, wherein the transmitting device comprises a cable modem (CM);

and

the receiving device comprises a Cable Modem Termination System (CMTS).

3. The system of claim 1, wherein the plurality of logical channels comprises a plurality of Synchronous Code Division Multiple Access (S-CDMA) channels.

4. The system of claim 1, wherein the plurality of logical channels comprises a plurality of multi-dimensional logical channels.

5. The system of claim 4, wherein one multi-dimensional logical channel of the plurality of multi-dimensional logical channels comprises at least one of a 2 dimensional logical channel and a 3 dimensional logical channel;

the 2 dimensional logical channel comprises a time dimension and a code dimension; and

the 3 dimensional logical channel comprises a time dimension, a code dimension, and a frequency dimension.

6. The system of claim 4, wherein the transmitting device simultaneously transmits the information to the receiving device using at least two multi-dimensional logical channels of the plurality of multi-dimensional logical channels.

7. The system of claim 1, wherein the plurality of active codes comprises a plurality of unused codes and the plurality of permitted codes;

and

the receiving device performs interference cancellation using the plurality of unused codes.

8. The system of claim 1, wherein a ratio of the first power per code over the second power per code is substantially at least one of:

an inverse of a ratio of a number of active codes within the plurality of active codes over a number of permitted codes within the plurality of permitted codes; and

a ratio of the number of permitted codes within the plurality of permitted codes over the number of active codes within the plurality of active codes.

9. The system of claim 1, wherein the transmitting device performs ranging and registering of the communication channel that communicatively couples the transmitting device and the receiving device using a plurality of maximally robust burst parameters;

and

the transmitting device sends a ranging burst to the receiving device via a robust logical channel, the robust logical channel being one of the plurality of logical channels.

10. The system of claim 9, wherein the plurality of maximally robust burst parameters comprises a highly robust and low order modulation.

11. The system of claim 9, wherein the plurality of maximally robust burst parameters comprises at least one of an extended preamble and a plurality of copies of a preamble.

12. The system of claim 11, wherein the receiving device performs parameter estimation of the communication channel using the plurality of copies of the preamble;

and

the receiving device generates an average parameter estimation by averaging over the plurality of copies of the preamble.

13. The system of claim 9, wherein the receiving device instructs the transmitting device to move to a multi-dimensional logical channel of the plurality of multi-dimensional logical channels when the ranging and registering of the communication channel is completed;

and

the transmitting device subsequently operates using the multi-dimensional logical channel of the plurality of multi-dimensional logical channels while employing a plurality of parameters having a higher order than the plurality of maximally robust burst parameters.

14. The system of claim 9, wherein the receiving device instructs the transmitting device to perform the ranging and registering of the communication channel.

15. The system of claim 9, wherein the transmitting device initiates the ranging and registering of the communication channel.

16. The system of claim 1, wherein the transmitting device uses a modulation when transmitting information using the plurality of active codes;

and

the transmitting device uses the modulation when transmitting information using the plurality of permitted codes.

17. The system of claim 1, wherein the transmitting device transmits information using the plurality of active codes at a first Signal to Noise Ratio (SNR);

and

the transmitting device transmits information using the plurality of permitted codes at a second SNR that is substantially greater than the first SNR.

18. The system of claim 1, wherein the transmitting device transmits information across the communication channel using the plurality of active codes at a throughput and efficiency;

and

the transmitting device transmits information across the communication channel using the plurality of permitted codes at the throughput and efficiency.

19. The system of claim 1, wherein the transmitting device comprises at least one of a satellite transmitter, a High Definition Television (HDTV) transmitter, a mobile transmitter, a base station transmitter, a mobile transceiver, a microwave transmitter, and a microwave transceiver;

and

the receiving device comprises at least one of a satellite receiver, a High Definition Television (HDTV) set top box receiver, a mobile receiver, a base station receiver, a mobile transceiver, a microwave receiver, and a microwave transceiver.

20. The system of claim 1, wherein the communication system comprises at least one of a cable modem communication system, a satellite communication system, a High Definition Television (HDTV) communication system, a cellular communication system, a microwave communication system, a point-to-point radio communication system, a uni-directional communication system, a bi-directional communication system, and a one to many communication system.

21. A cable modem communication system that supports attenuated transmission adaptation, the system comprising:

a Cable Modem (CM) that is operable to transmit information using a plurality of active codes, each active code of the plurality of active codes being transmitted using a first power per code;

a Cable Modem Termination System (CMTS), communicatively coupled to the CM via a communication channel, that is operable to receive transmitted information from the CM;

wherein the CMTS instructs the CM to transmit information using a plurality of permitted codes;

the CMTS instructs the CM to transmit each permitted code of the plurality of permitted codes using a second power per code;

the communication channel comprises a spectrum portion that is partitioned into a plurality of logical channels; and

the CM performs ranging and registering of the communication channel that communicatively couples the CM and the CMTS using a plurality of maximally robust burst parameters and using a robust logical channel, the robust logical channel comprising one of the plurality of logical channels.

22. The system of claim 21, wherein the plurality of logical channels comprises a plurality of multi-dimensional logical channels.

23. The system of claim 22, wherein one multi-dimensional logical channel of the plurality of multi-dimensional logical channels comprises at least one of a 2 dimensional logical channel and a 3 dimensional logical channel;

the 2 dimensional logical channel comprises a time dimension and a code dimension; and

the 3 dimensional logical channel comprises a time dimension, a code dimension, and a frequency dimension.

24. The system of claim 23, wherein the CM simultaneously transmits the information to the CMTS using at least two multi-dimensional logical channels of the plurality of multi-dimensional logical channels.

25. The system of claim 21, wherein the plurality of active codes comprises a plurality of unused codes and the plurality of permitted codes;

and

the CMTS performs interference cancellation using the plurality of unused codes.

26. The system of claim 21, wherein a ratio of the first power per code over the second power per code is substantially at least one of:

an inverse of a ratio of a number of active codes within the plurality of active codes over a number of permitted codes within the plurality of permitted codes; and

a ratio of the number of permitted codes within the plurality of permitted codes over the number of active codes within the plurality of active codes.

27. The system of claim 21, wherein the plurality of maximally robust burst parameters comprises a highly robust and low order modulation.

28. The system of claim 21, wherein the plurality of maximally robust burst parameters comprises at least one of an extended preamble and a plurality of copies of a preamble.

29. The system of claim 28, wherein the CMTS performs parameter estimation of the communication channel using the plurality of copies of the preamble;

and

the CMTS generates an average parameter estimation by averaging over the plurality of copies of the preamble.

30. The system of claim 21, wherein the CMTS instructs the CM to move to a multi-dimensional logical channel of the plurality of multi-dimensional logical channels when the ranging and registering of the communication channel is completed;

and

the CM subsequently operates using the multi-dimensional logical channel of the plurality of multi-dimensional logical channels while employing a plurality of parameters having a higher order than the plurality of maximally robust burst parameters.

31. The system of claim 21, wherein the CMTS instructs the CM to perform the ranging and registering of the communication channel.

32. The system of claim 21, wherein the CM initiates the ranging and registering of the communication channel.

33. The system of claim 21, wherein the CM uses a modulation when transmitting information using the plurality of active codes;

and

the CM uses the modulation when transmitting information using the plurality of permitted codes.

34. The system of claim 21, wherein the CM transmits information using the plurality of active codes at a first Signal to Noise Ratio (SNR);

and

the CM transmits information using the plurality of permitted codes at a second SNR that is substantially greater than the first SNR.

35. The system of claim 21, wherein the CM transmits information across the communication channel using the plurality of active codes at a throughput and efficiency;

and

the CM transmits information across the communication channel using the plurality of permitted codes at the throughput and efficiency.

36. An attenuated transmission adaptation method, the method comprising:

instructing a Cable Modem (CM), using a Cable Modem Termination System (CMTS), to reduce a number of transmit codes from a plurality of active codes to a plurality of permitted codes, the reduction in the number of transmit codes being a reduction factor;

instructing the CM to increase a transmitted power per code for each permitted code of the plurality of permitted codes by an inverse of the reduction factor;

wherein the CM and the CMTS are communicatively coupled via a communication channel; and

the communication channel comprises a spectrum portion that is partitioned into a plurality of logical channels.

37. The method of claim 36, wherein the plurality of logical channels comprises a plurality of multi-dimensional logical channels.

38. The method of claim 37, wherein one multi-dimensional logical channel of the plurality of multi-dimensional logical channels comprises at least one of a 2 dimensional logical channel and a 3 dimensional logical channel;

the 2 dimensional logical channel comprises a time dimension and a code dimension; and

the 3 dimensional logical channel comprises a time dimension, a code dimension, and a frequency dimension.

39. The method of claim 37, wherein the CM simultaneously transmits the information to the CMTS using at least two multi-dimensional logical channels of the plurality of multi-dimensional logical channels.

40. The method of claim 36, further comprising performing ranging and registering of the communication channel that communicatively couples the CM and the CMTS using a plurality of maximally robust burst parameters and using a robust logical channel.

41. The method of claim 40, wherein the plurality of maximally robust burst parameters comprises a highly robust and low order modulation.

42. The method of claim 40, wherein the plurality of maximally robust burst parameters comprises at least one of an extended preamble and a plurality of copies of a preamble.

43. The method of claim 42, further comprising performing parameter estimation of the communication channel, at the CMTS, by averaging over the plurality of copies of the preamble.

44. The method of claim 40, further comprising instructing the CM, using the CMTS, to move to a multi-dimensional logical channel of the plurality of multidimensional logical channels when the ranging and registering of the communication channel is completed;

and

subsequently operating the CM using the multi-dimensional logical channel of the plurality of multi-dimensional logical channels while employing a plurality of parameters having a higher order than the plurality of maximally robust burst parameters.

45. The method of claim 40, further comprising instructing the CM, using the CMTS, to perform the ranging and registering of the communication channel.

46. The method of claim 40, wherein the CM initiates the ranging and registering of the communication channel.

47. The method of claim 36, further comprising transmitting information across the communication channel, from the CM to the CMTS, using the plurality of active codes and using a modulation;

and

transmitting information across the communication channel, from the CM to the CMTS, using the plurality of permitted codes and using the modulation.

48. The method of claim 36, further comprising transmitting information across the communication channel, from the CM to the CMTS, using the plurality of active codes at a first Signal to Noise Ratio (SNR);

and

transmitting information across the communication channel, from the CM to the CMTS, using the plurality of permitted codes at a second SNR that is substantially greater than the first SNR.

49. The method of claim 36, further comprising transmitting information across the communication channel, from the CM to the CMTS, using the plurality of active codes at a throughput and efficiency;

and

transmitting information across the communication channel, from the CM to the CMTS, using the plurality of permitted codes at the throughput and efficiency.