Multi-detection of heartbeat to reduce error probability

• US 20030095517A1
• Filed: 06/12/2002
• Published: 05/22/2003
• Est. Priority Date: 12/17/1997
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Tantivy Communications Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr.
• Granted Patent: US 7,394,791 B2
• Time in Patent Office: Days
• US Class Current: 370/332
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04J 13/0077 Multicode, e.g. multiple codes assigned to one user
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 25/14 Channel dividing arrangements , i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 7/06 the synchronisation signals differing from the information signals in amplitude, polarity or frequency or length
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 11/0428 Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
• CPC Class Codes: H04Q 2213/13098 Mobile subscriber
• CPC Class Codes: H04Q 2213/13202 Network termination [NT]
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13209 ISDN
• CPC Class Codes: H04Q 2213/13216 Code signals, frame structure
• CPC Class Codes: H04Q 2213/1327 Release and resetting of connection
• CPC Class Codes: H04Q 2213/13298 Local loop systems, access network
• CPC Class Codes: H04Q 2213/13332 Broadband, CATV, dynamic bandwidth allocation
• CPC Class Codes: H04Q 2213/1336 Synchronisation
• CPC Class Codes: H04Q 2213/13389 : LAN, internet
• CPC Class Codes: H04W 28/04 : Error control
• CPC Class Codes: H04W 28/18 : Negotiating wireless communication parameters
• CPC Class Codes: H04W 72/0446 : Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 74/004 : in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 74/0833 : Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 84/14 : WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Abstract

A communications system improves performance of detecting a signal having an indication of a request to change communications states by making at least two positive identifications of the request in a given time frame. The system may further improve performance by applying a difference in power levels for a non-request state (i.e., steady state or ‘control hold’ state) versus a request state (i.e., ‘request to change’ state). In one particular application, a base station determines a request to change communications states with a reasonably high probability of detection and a reasonably low probability of false detection. The system has a reduced number of erroneous communications states, such as erroneous traffic channel allocations. The detection technique is compatible with 1xEV-DV systems and I-CDMA systems, but general enough to support systems employing various other communications protocols used in wired and wireless communications systems.

Claims

1. In a wireless communications system, a method for determining a request to change communications state, the method comprising:

receiving at least one signal having a first indication of a first communications state and a second indication for a request to change to a second communications state;

counting at least one of the indications; and

based on the measurement, determining whether a request to change communications states has been made.

2. The method according to claim 1 wherein the step of determining includes comparing the number of received second indications against a threshold of at least two.

3. The method according to claim 2 wherein counting the detected indications resets for non-consecutive detected indications.

4. The method according to claim 2 wherein counting the detected indications resets if said threshold of at least two second indications is not achieved in a given timespan.

5. The method according to claim 1 further including monitoring at least first and second time slots for said first and second indications.

6. The method according to claim 5 wherein the detecting includes applying independent thresholds for detection to the indications.

7. The method according to claim 5 wherein the time slots are mutually exclusive.

8. The method according to claim 7 wherein a request to change communications states is caused by detecting a repetition of the first and second indications above a given threshold, and a request not to change communications states is caused by detecting a repetition of fewer than both the first and second indications above a given threshold.

9. The method according to claim 1 further including causing a present communications state to change in response to a determination that a request has been made.

10. The method according to claim 1 wherein the first indication has a first energy level and the second indication has a second energy level and further including detecting the indications based on the energy levels according to alternative criteria.

11. The method according to claim 10 wherein the detecting includes comparing the first energy level against a first energy level threshold and comparing the second energy level against a second energy level threshold.

12. The method according to claim 11 wherein the detecting includes integrating time slots in a signal channel in which said at least one signal is received, said first and second energy levels dependent on occupancy of time slots.

13. The method according to claim 11 wherein the criteria include at least one of the following:

the first energy level exceeds a first energy level threshold, the second energy level exceeds a second energy level threshold, the second indication occupies time slots, the first and second indications occupy time slots in mutually exclusive code channels, and the first and second indications occupy mutually exclusive time slots.

14. The method according to claim 13 wherein counting indications includes counting only indications that are detected based on the energy levels according to the alternative criteria.

15. The method according to claim 14 further including adjusting the second energy level of the signal based on a target probability of detection.

16. The method according to claim 14 further including adjusting the second energy level of the signal based on a target probability of false detection.

17. The method according to claim 1 wherein the first communications state is a standby state and the second communications state is a payload state.

18. The method according to claim 1 wherein the communications states are data communications states.

19. The method according to claim 1 wherein the communications system is a code division multiple access (CDMA) or orthogonal frequency division multiplexing (OFDM) wireless communications system.

20. In a communications system, an apparatus for determining a request for changing communications state, the apparatus comprising:

a receiver to receive at least one signal having (i) a first indication of a first communications state and (ii) a second indication for a request to change to a second communications state;

a counter coupled to the receiver to count at least one of the first or second indications; and

a logic unit coupled to the measuring unit to determine whether a request to change communications states has been made.

21. The apparatus according to claim 20 wherein the logic unit compares the number of received second indications against a threshold of at least two.

22. The apparatus according to claim 21 wherein the counter resets for non-consecutive detected indications.

23. The apparatus according to claim 21 wherein the counter resets if said threshold of two detected indications is not achieved in a given time span.

24. The apparatus according to claim 20 further including at least one monitor to monitor at least first and second time slots for said first and second indications.

25. The apparatus according to claim 24 wherein the measuring unit applies independent thresholds for detection of the indications.

26. The apparatus according to claim 24 wherein the time slots are mutually exclusive.

27. The apparatus according to claim 26 wherein the logic unit causes a request to change communications states in response to determining repetition rates above respective thresholds in both mutually exclusive time slots, and the logic unit does not cause a request to change communications states in response to determining repetition rates above respective thresholds in fewer than both mutually exclusive time slots.

28. The apparatus according to claim 20 further including a state control unit coupled to the logic unit used to cause the communications state to change in response to a determination that a request has been made.

29. The apparatus according to claim 20 wherein the first indication has a first energy level and the second indication has a second energy level and wherein the counter counts the indications based on the energy levels according to alternative criteria.

30. The apparatus according to claim 29 wherein the measuring unit includes a comparator to compare the first energy level against a first energy level threshold and to compare the second energy level against a second energy level threshold.

31. The apparatus according to claim 29 wherein the measuring unit includes integrating time slots in a signaling channel in which said at least one signal is received, said first and second energy levels dependent on occupancy of time slots.

32. The apparatus according to claim 29 wherein the criteria include at least one of the following:

the first energy level exceeds a first energy level threshold, the second energy level exceeds a second energy level threshold, the second indication occupies time slots, the first and second indications occupy time slots in mutually exclusive code channels, and the first and second indications occupy mutually exclusive time slots.

33. The apparatus according to claim 29 wherein the counter counts only indications that are detected based on the energy levels according to the alternative criteria.

34. The apparatus according to claim 33 further including adjusting the second energy level of the signal based on a target probability of detection.

35. The apparatus according to claim 33 further including adjusting the second energy level of the signal based on a target probability of false detection.

36. The apparatus according to claim 20 wherein the first communications state is a standby state and the second communications state is a payload state.

37. The apparatus according to claim 20 wherein the communications states are data communications states.

38. The apparatus according to claim 20 wherein the communications system is a code division multiple access (CDMA) or orthogonal frequency division multiplexing (OFDM) wireless communications system.

39. In a wireless communications system, an apparatus for determining a request to change communications state, the apparatus comprising:

means for receiving at least one signal having (i) a first indication of a first communications state and (ii) a second indication for a request to change to a second communications state;

means for counting the detected indications; and

means for determining whether a request to change communications states has been made.

40. In a communications system, a method for making a request to change communications state, the method comprising:

selecting indications to be transmitted in a signal, the indications associated with data communications states and countable by a receiving system to determine whether a request to change communications states has been made; and

transmitting the signal including at least one indication to the receiving system.

41. The method according to claim 40 wherein the indications are transmitted consecutively in expectation of being counted as consecutive indications by the receiving system.

42. The method according to claim 40 wherein at least two detected indications are included in the signal in a given time span.

43. The method according to claim 40 wherein selecting the indications is done according to energy levels associated with the indications.

44. The method according to claim 40 wherein transmitting the signal includes multiplexing the indications in time slots in a signaling channel.

45. The method according to claim 40 wherein transmitting the signal includes applying the indications to the signal in at least one of the following manners:

in mutually exclusive code channels, in mutually exclusive time slots, in vacant time slots, with respective energy levels, with a given repetition rate, or as a non-coded carrier signal.

46. The method according to claim 40 wherein the communications states include a standby state and a payload state.

47. The method according to claim 40 wherein the communications states are data communications states.

48. The method according to claim 40 wherein the respective energy levels are based on a target probability of detection.

49. The method according to claim 40 wherein the respective energy levels are based on a target probability of false detection.

50. The method according to claim 40 wherein the communications system is a code division multiple access (CDMA) or orthogonal frequency division multiplexing (OFDM) wireless communications system.

51. In a communications system, an apparatus for making a request to change communications state, the apparatus comprising:

a selector to select indications to be transmitted in a signal, the indications associated with communications states and countable by a receiving system to determine whether a request to change a communications state has been made; and

a transmitter coupled to the selector to transmit the signal including at least one indication to the receiving system.

52. The apparatus according to claim 51 wherein the selector selects the indications in a manner that the indications are transmitted consecutively in expectation of being counted as consecutive indications by the receiving system.

53. The apparatus according to claim 51 wherein the selector selects at least two indications to be included in the signal in a given time span.

54. The apparatus according to claim 51 further including a multiplexer coupled to the selector and transmitter to apply the indications in time slots in a signaling channel.

55. The apparatus according to claim 51 wherein the selector and transmitter apply the indications in at least one of the following manners:

in mutually exclusive code channels, in mutually exclusive time channels, in vacant time slots, with respective energy levels, with a given repetition rate, or as a non-coded carrier signal.

56. The apparatus according to claim 51 wherein the communications states include a standby state and a payload state.

57. The apparatus according to claim 51 wherein the communications states are data communications states.

58. The apparatus according to claim 51 wherein the selector applies the indications to the signal based on a target probability of detection.

59. The apparatus according to claim 51 wherein the selector applies the indications to the signal based on a target probability of false detection.

60. The apparatus according to claim 51 wherein the communications system is a code division multiple access (CDMA) or orthogonal frequency division multiplexing (OFDM) wireless communications system.

61. In a communications system, an apparatus for making a request to change communications state, the apparatus comprising:

means for selecting indications to be transmitted in a signal, the indications associated with communications states and countable by a receiving system to determine whether a request to change a communications state has been made; and

transmitting means to transmit the signal including at least one indication to the receiving system.