Method for demodulating information in a communication system that supports multiple modulation schemes

• US 6,125,148 A
• Filed: 08/29/1997
• Issued: 09/26/2000
• Est. Priority Date: 08/29/1997
• Status: Expired due to Term

• Current Assignee: Cluster LLC (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Skold, Johan, Hook, Mikael, Schramm, Peter, Muller, Frank, Frodigh, Carl Magnus
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Maddox, Michael W.
• Application Number:
  US08/921,374
• Time in Patent Office: 1,124 Days
• Field of Search: 375/261, 375/266, 375/264, 375/280, 375/281, 375/298, 375/308, 375/332, 375/203, 370/280, 370/294, 370/336, 370/337, 370/345, 370/347, 370/498, 370/261, 370/264, 370/216, 370/322, 370/323
• US Class Current: 375/261
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453

Abstract

A method of demodulating voice or data and control information in systems that support multiple modulation schemes modulates voice or data using a first linear modulation scheme, such as 16QAM modulation scheme, and modulates control information using a second linear modulation scheme, for example, QPSK modulation scheme, that has the same symbol rate as that of the first modulation scheme. The first linear modulation scheme has a higher modulation level than the second linear modulation scheme. Information modulated using the second linear modulation scheme, which uses a reduced signal set of the first linear modulation scheme, are demodulated using the same demodulator that is used for demodulating information modulated using the first linear modulation scheme. Also, in-band signalling information within a traffic channel, such as stealing flags, are modulated using the second modulation scheme.

Claims

1. A method for communicating information, comprising the step of:

modulating a first set of information using a first linear modulation scheme;

modulating a second set of information using a second linear modulation scheme, wherein the first and second linear modulation schemes have the same symbol rate, and wherein the second modulation scheme uses a reduced signal set of the first linear modulation scheme; and

demodulating the first set of information and the second set of information using the same demodulator.

2. The method of claim 1, wherein the same demodulator demodulates signals modulated using the first modulation scheme.

3. The method of claim 2, wherein the first linear modulation scheme has a higher level of modulation than the second modulation scheme.

4. The method of claim 3, wherein the second linear modulation scheme uses the outer signal points in modulation constellation of the first linear modulation scheme to communicate the second set of information.

5. The method of claim 4 further including the steps of communicating the first set of information over a traffic channel and the second set of information over a control channel.

6. The method of claim 5, wherein the control channel is an associated control channel.

7. The method of claim 6, wherein the associated control channel is a fast associated control channel.

8. The method of claim 6, wherein the associated control channel is a slow associated control channel.

9. The method of claim 3, wherein the second set of information is in-band signalling information.

10. The method of claim 9, wherein the in-band signalling information correspond to at least one of a modulation type, a channel coding or a speech coding.

11. The method of claim 3, wherein the second set of information includes stealing flags that indicate whether a transmitted burst contains control information or voice and data information.

12. The method of claim 3, wherein the second set of information is a training sequence.

13. The method of claim 3, wherein the first linear modulation scheme and the second linear modulation scheme use the same pulse shaping.

14. The method of claim 3, wherein the first and second linear modulation schemes use the same burst format.

15. The method in claim 3, wherein the first modulation scheme is a QAM modulation scheme and the second modulation scheme is a QPSK modulation scheme.

16. A method for communicating information between a base station and a mobile station comprising:

communicating voice or data using a first linear modulation scheme;

communicating in-band signalling information using a second linear modulation scheme which is different from the first linear modulation scheme; and

demodulating the voice or data and the in-band signalling information using the same demodulator.

17. The method of claim 16, wherein the first and second linear modulation schemes have the same symbol rate, and wherein the second modulation scheme uses a reduced signal set of the first linear modulation scheme.

18. The method of claim 17, wherein the same demodulation scheme corresponds to demodulation of signals modulated using the first linear modulation scheme.

19. The method of claim 17, wherein the in-band signalling information includes stealing flags that indicate whether a transmitted burst contains control information or voice and data information.

20. The method of claim 17, wherein the in-band signalling information indicates at least one of a modulation type, a channel coding, or a speech coding used by a transmitted burst.

21. A method of communication between a base station and a mobile station comprising:

modulating voice or data over a traffic channel using a first linear modulation scheme;

modulating control information over a control channel that is associated with the traffic channel using a second linear modulation scheme which is different from the first linear modulation scheme; and

demodulating the voice or data and control information using the same demodulator.

22. The method of claim 21, wherein the first and the second linear modulation schemes have the same symbol rate.

23. The method of claim 22, wherein the same demodulator demodulates signals modulated using the first linear modulation scheme.

24. The method of claim 21, wherein the associated control channel is a fast associated control channel.

25. The method of claim 21, wherein the associated control channel is a slow associated control channel.

26. The method of claim 21, wherein the first linear modulation scheme has a higher level of modulation than the second linear modulation scheme.

27. The method of claim 26, wherein the second linear modulation scheme uses a reduced signal set of the first linear modulation scheme.

28. The method of claim 21, wherein the first and second linear modulation schemes have the same level.

29. The method of claim 21, wherein the first and second linear modulation schemes use the same pulse shaping.

30. The method of claim 21, wherein the first and second linear modulation schemes use the same burst format.

31. The method in claim 21, wherein the first and second linear modulation schemes use the same training sequences.

32. The method in claim 21, wherein the first linear modulation scheme is a QAM modulation scheme and the second linear modulation scheme is a QPSK modulation scheme.

33. A demodulator comprising:

means for demodulating a first set of information that are modulated using a first linear modulation scheme; and

means for demodulating a second set of information that are modulated using a second linear modulation scheme, wherein the first and second linear modulation schemes have the same symbol rate, and wherein the second modulation scheme uses a reduced signal set of the first linear modulation scheme; and

wherein the first set of information and the second set of information are demodulated using the same demodulator.

34. A method for communicating information, comprising the step of:

modulating a first set of information using a first modulation scheme;

modulating a second set of information using a second modulation scheme, wherein the first and second modulation schemes have the same symbol rate, and wherein the second modulation scheme uses a reduced signal set of the first modulation scheme; and

demodulating the first set of information and the second set of information using the same demodulator.

35. The method of claim 34, wherein the first modulation scheme is a linear modulation scheme and the second modulation scheme is a non-linear modulation scheme.

36. The method of claim 35, wherein the non-linear modulation scheme is GMSK modulation scheme and the linear modulation scheme is a high level modulation scheme.

37. The method of claim 34, wherein the first modulation scheme has a higher level of modulation than the second modulation scheme.

38. The method of claim 34 further including the steps of communicating the first set of information over a traffic channel and the second set of information over a control channel.

39. The method of claim 38 wherein the control channel is an associated control channel.

40. The method of claim 37 wherein the second set of information is in-band signaling information.

41. The method of claim 40, wherein the in-band signaling information correspond to at least one of a modulation type, a channel coding or a speech coding used for a transmitted burst.

42. The method of claim 34 wherein the second set of information includes stealing flags that indicate whether a transmitted burst contains control information or voice and data information.

43. The method of claim 34 wherein the second set of information is a training sequence.