Verification of transmit power levels in a signal point limited transmission system

• US 6,359,932 B2
• Filed: 12/18/2000
• Issued: 03/19/2002
• Est. Priority Date: 05/11/1998
• Status: Expired due to Term

• Current Assignee: Modern Telecom Systems, LLC (Ideahub, Inc.)
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Olafsson, Sverrir
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): Tran, Khai
• Application Number:
  US09/740,567
• Publication Number:
  US 20010000705A1
• Time in Patent Office: 456 Days
• Field of Search: 375/259, 375/222, 375/216, 375/345, 375/377, 375/223, 375/268, 379/93.01, 379/27
• US Class Current: 375/259
• CPC Class Codes: H04L 25/4927 using levels matched to the quantisation levels of the channel
• CPC Class Codes: H04L 5/1453 of modulation type
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors

Abstract

A pulse code modulation modem system utilizes the same total average transmit power formula for designing signal point constellations and for verifying that the transmit power of the signal point constellations are within a designated maximum power limit. The transmit power of the signal point constellations designed by the client modem is also calculated by the server modem to verify that the transmit power limit imposed upon the server modem is not exceeded. In addition, the modem system is capable of designating a transmit power limit associated with one or more training signal points or a training sequence for use during a training mode.

Claims

1. In a first modem capable of communicating in analog mode, a method for initiating verification of transmit power levels in a signal point limited transmission system, wherein said first modem is configured to communicate over a communication channel with a second modem capable of communicating in a digital mode, said method comprising the steps of:

receiving a transmit power limit;

selecting at least one signal point constellation having a first computed transmit power less than or equal to said transmit power limit, said first computed transmit power being calculated in accordance with a predetermined power calculation formula; and

transmitting said at least one signal point constellation to said second modem to initiate verification of the transmit power level of said at least one signal point constellation.

2. The method according to claim 1, further comprising the step of initiating a data communication session utilizing said at least one signal point constellation.

3. The method according to claim 2, wherein said data communication session initiating step is performed if said verification of said transmit power is successful.

4. The method according to claim 1, wherein said first computed transmit power is associated with an upper bound calculation with respect to said predetermined power calculation formula.

5. The method according to claim 1, further comprising the step of selecting said predetermined power calculation formula from a plurality of formulas.

6. The method according to claim 5, wherein said selecting step is responsive to current operating characteristics of said transmission system.

7. A first modem capable of communicating in an analog mode, configured to communicate over a communication channel with a second modem capable of communicating in a digital mode, in a signal point limited transmission system, said first modem comprising:

a receiver configured to receive a transmit power limit;

a processor configured to select at least one signal point constellation having a first computed transmit power less than or equal to said transmit power limit, said first computed transmit power being calculated in accordance with a predetermined power calculation formula; and

a transmitter configured to transmit said at least one signal point constellation to said second modem to initiate verification of the transmit power of said at least one signal point constellation.

8. The first modem according to claim 7, wherein said processor is further configured to initiate a data communication session utilizing said at least one signal point constellation.

9. The first modem according to claim 8, wherein said processor initiates said data communication session if said verification of said transmit power is successful.

10. The first modem according to claim 8, wherein said first computed transmit power is associated with an upper bound calculation with respect to said predetermined power calculation formula.

11. The first modem according to claim 7, wherein said predetermined power calculation formula is selected from a plurality of formulas.

12. The first modem according to claim 11, wherein said predetermined power calculation formula is selected in accordance with current operating characteristics of said transmission system.

13. A first modem capable of communicating in an analog mode, configured to communicate over a communication channel with a second modem capable of communicating in a digital mode, said first modem comprising:

means for receiving a transmit power limit;

means for selecting at least one signal point constellation having a first computed transmit power less than or equal to said transmit power limit, said first computed transmit power being calculated in accordance with a predetermined power calculation formula; and

means for transmitting said at least one signal point constellation to said second modem to initate verification of the transmit power of said at least one signal point constellation.

14. The first modem according to claim 13, wherein said means for selecting includes means for initiating a data communication session utilizing said at least one signal point constellation.

15. The first modem according to claim 14, wherein said means for selecting includes means for initiating said data communication session if said verification of said transmit power is successful.

16. The first modem according to claim 13, wherein said first computed transmit power is associated with an upper bound calculation with respect to said predetermined power calculation formula.

17. The first modem according to claim 13, wherein said predetermined power calculation formula is selected from a plurality of formulas.

18. The first modem according to claim 13, wherein said predetermined power calculation formula is selected in accordance with current operating characteristics of said transmission system.

19. A computer program product, said computer program product comprising:

code for enabling access to a transmit power limit of the data transmission system;

code for selecting, at a first modem capable of communicating in an analog mode, at least one signal point constellation such that the signal point constellation has a first computed transmit power less than or equal to said transmit power limit; and

code for transmitting said at least one signal point constellation to a second modem capable of communicating in a digital mode to initiate verification of the transmit power of said at least one signal point constellation.

20. The computer program product of claim 19, wherein said at least one signal point constellation comprises PCM signal points.

21. The computer program product of claim 19, wherein said first computed transmit power is calculated in accordance with a power calculation formula.

22. The computer program product of claim 21, wherein said first computed transmit power is associated with an upper bound calculation with respect to said power calculation formula.

23. The computer program product of claim 19, further comprising code for calculating said transmit power limit in accordance with a power calculation formula.

24. The computer program product of claim 23, wherein said code for calculating is configured to calculate a total average transmit power level.

25. The computer program product of claim 19, wherein the code for determining said transmit power limit resides at said second modem.

26. The computer program product of claim 25, wherein the code for determining the transmit power limit further comprises code for enabling communication the transmit power limit between the first modem and the second modem.

27. A computer program embodying instructions executable by a computer to perform method, the method steps comprising:

generating a transmit power limit for the system;

determining a set of signal points;

verifying said set set of signal points; and

storing said set of signal points in a database if said verifying step confirms a second transmit power is less than or equal to the transmit power limit.

28. The computer program of claim 27, wherein said generating a transmit power limit for the system step is executed by performing one of the steps of:

retrieving a stored transmit power limit from a memory element; and

calculating said transmit power limit in accordance with a predetermined transmit power formula.

29. The computer program of claim 27, wherein said determining a set of signal points steps includes one of the steps of:

calculating a transmit power associated with said set of signal points in accordance with a predetermined transmit power formula; and

selecting said set of signal points such that said calculated transmit power is less than or equal to said transmit power limit.

30. The computer program of claim 27 wherein said verifying said set of signal points step includes the steps of:

calculating a second transmit power associated with said set of signal points in accordance with a predetermined transmit power formula; and

determining whether said second transmit power is less than or equal to said transmit power limit.

31. A computer data signal representing sequences of instructions which, when executed by a modem system, enables said modem system to:

provide for the determination of a transmit power limit for said system;

provide for the selection of a set of signal point constellations to satisfy a condition relative to said transmit power limit; and

provide for the verification that said set of signal point constellations satisifies said condition relative to said transmit power limit.

32. The computer data signal of claim 31, wherein said data signal further enables said modem system to provide for the querying of whether said condition was satisfied.

33. The computer data signal of claim 31, further enabling the modem system to:

provide for the rejection of said set of signal point constellations when the condition is not satisfied; and

provide for the acceptance of said set of signal point constellations when the condition is satisfied.

34. The computer data signal of claim 31, further enabling the modem system to provide for the initiation of a data communication session utilizing the verified set of signal point constellations.

35. The computer data signal of claim 31, wherein said step of establishing a transmit power limit for said system includes selecting a maximum transmit power from a table stored in a memory.

36. A machine-readable program storage medium having a program stored thereon, said program configured to enable performance of the following steps:

determining a transmit power limit;

selecting at least one signal point constellation; and

communicating said at least one signal point constellation to initiate verification of the transmit power of said at least one signal point constellation.

37. The machine-readable program storage medium of claim 36, wherein selection of said at least one signal point constellation is such that said at least one signal point constellation has s first computed transmit power less than or equal to said transmit power limit, said first computed transmit power being calculated in accordance with a predetermined power calculation formula.

38. The machine-readable program storage medium of claim 36, wherein said program is further configured to enable performance of the step of initiating a data communication session utilizing said at least one signal point constellation.

39. The machine-readable program storage medium of claim 38, wherein said initiating step is performed if said verification of said transmit power is successful.

40. The machine-readable program storage medium of claim 36, wherein said first computed transmit power is associated with an upper bound calculation with respect to said predetermined power calculation formula.

41. The machine-readable program storage medium of claim 36, wherein said program is further configured to enable performance of the step of selecting said predetermined power calculation formula from a plurality of formulas.

42. The machine-readable program storage medium of claim 41, wherein said selecting step is responsive to current operating characteristics of said transmission system.

43. The machine-readable program storage medium of claim 36, wherein said program is stored in a random access memory (RAM).

44. The machine-readable program storage medium of claim 36, wherein said program is stored in a read-only memory (ROM).

45. The machine-readable program storage medium of claim 36, wherein said program is stored in an electrically-erasable-and-programmable-read-only-memory (EEPROM).

46. The machine-readable program storage medium of claim 36, wherein said program is stored in a memory region provided within a digital signal processor.

47. The machine-readable program storage medium of claim 36, wherein said step of determining a transmit power limit includes receiving a five-bit binary number corresponding to said transmit power limit.

48. A computer data signal for establishing a data communication session between a first modem capable of communicating in an analog mode and a second modem capable of communicating in a digital mode, said computer data signal comprising:

instructions capable of enabling said first modem to receive a transmit power limit from said second modem;

instructions capable of enabling said first modem to select a signal point constellation such that a first computed transmit power, as calculated by said first modem, is within said transmit power limit;

instructions capable of enabling said first modem to transmit said signal point constellation to said second modem such that said second modem is capable of verifying that siad first computed transmit power is within said transmit power limit, and capable of initiating a data communication session utilizing said signal point constellation upon verification that said first computed transmit power is within said transmit power limit, or capable of rejecting said signal point constellation upon verification that said first computed transmit power is not within said transmit power limit.

49. The computer data signal of claim 48, wherein said first computed transmit power is less than or equal to said transmit power limit.

50. The computer data signal of claim 48, wherein said first computed transmit power is associated with an upper bound calculation with respect to a power calculation formula.

51. A first modem capable of communicating in an analog mode, configured to communicate over a communication channel with a second modem capable of communicating in a digital mode, in a signal point limited transmission system, said second modem comprising:

means for sending a transmit power limit to said first modem;

means for receiving at least one signal point constellation from said first modem;

means for calculating a computed transmit power based on said at least one signal point constellation; and

means for verifying that said computed transmit is less than or equal to said transmit power limit.

52. A first modem capable of communicating in an analog mode, configured to communicate over a communication channel with a second modem capable of communicating in a digital mode, said second modem comprising:

a transmitter configured to transmit a power limit;

a receiver configured to receive at least one signal point constellation from said first modem; and

a processor configured to calculate a computed transmit power based on said at least one signal point constellation, and to verify that said computed transmit is less than or equal to said transmit power limit.