Transmittal of heartbeat signal at a lower level than heartbeat request

• US 20030086399A1
• Filed: 06/12/2002
• Published: 05/08/2003
• Est. Priority Date: 06/01/1998
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Tantivy Communications Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr.
• Granted Patent: US 7,221,664 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04L 1/165 Variable formats
• 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 7/06 the synchronisation signals differing from the information signals in amplitude, polarity or frequency or length
• 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 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/325 : Power control of control or pilot channels
• CPC Class Codes: H04W 52/50 : at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 74/0866 : using a dedicated channel for access
• CPC Class Codes: H04W 76/10 : Connection setup
• CPC Class Codes: H04W 76/28 : Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: H04W 8/005 : Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/14 : WLL [Wireless Local Loop]; RLL [Radio Local Loop]
• CPC Class Codes: H04W 88/02 : Terminal devices

Abstract

A communication system, such as a wireless CDMA system, detects markers with fewer errors by having field units transmit the markers at different power levels (e.g., 9 dB for one marker and 11 dB for another marker). The difference in power levels of the markers allows the base station to identify the request markers using alternative criteria with a low probability of error, where the alternative criteria may include comparing the markers to respective energy level thresholds, monitoring occupancy of time slots, occupancy of mutually exclusive code channels, or combinations thereof. For example, in one particular embodiment, a request marker, which is generally a high priority marker, is transmitted with higher power, which improves the probability of detection and reduces the probability of false detection of the request marker.

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 having a first energy level;

receiving said at least one signal having a second indication for a request to change to a second communications state and having a second energy level; and

detecting the indications according to alternative criteria.

2. The method according to claim 1 wherein the detecting includes comparing a first energy level threshold against the first energy level and comparing a second energy level threshold against the second energy level.

3. The method according to claim 2 wherein the detecting includes integrating time slots in a signaling channel in which said at least one signal is received, said first and second energy levels being dependent on occupancy of respective time slots.

4. The method according to claim 2 further including causing the communications system to change to the second communications state if the detected energy level of said at least one signal is determined to be above the second energy level threshold.

5. The method according to claim 2 further including causing the communications system to change to the second communications state if the detected energy level of said at least one signal is determined to be below the second energy level threshold.

6. The method according to claim 1 wherein the detecting includes monitoring an occupancy of time slots used to indicate the request to change communications states.

7. The method according to claim 6 wherein the detecting includes applying independent thresholds for detection to the time slots.

8. The method according to claim 6 wherein the time slots are mutually exclusive.

9. The method according to claim 8 wherein a request to change communications states is caused by detecting energy levels above respective thresholds in both mutually exclusive time slots, and a request not to change communications states is caused by detecting energy levels above respective energy thresholds on fewer than both mutually exclusive time slots.

10. The method according to claim 1 wherein the detecting includes monitoring occupancy of mutually exclusive code channels.

12. The method according to claim 1 wherein, based on the energy level of the first energy level, the detecting includes setting at least one integration time and an energy level threshold.

13. The method according to claim 1 wherein, based on the transmitted power levels of said at least one signal, the detecting includes setting an energy level threshold.

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

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

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

17. The method according to claim 1 further including adjusting the second energy level of the signal based on a target probability of detection.

18. The method according to claim 1 further including adjusting the second energy level of the signal based on a target probability of false detection.

11. The mutually exclusive code channels have respective thresholds for detection.

19. In a wireless 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 at a first energy level and (ii) a second indication for a request to change to a second communications state at a second energy level; and

a detector coupled to the receiver to detect the indications according to alternative criteria.

20. The apparatus according to claim 19 wherein the detector includes a comparator to compare a first energy level threshold against the first energy level and to compare a second energy level threshold against the second energy level.

21. The apparatus according to claim 20 wherein the detector includes an integrator to integrate over time slots in a signaling channel in which said at least one signal is received, said first and second energy levels being dependent on occupancy of respective time slots

22. The apparatus according to claim 20 further including a state selector to cause the communications system to change to the second communications state if the detected energy level of said at least one signal is determined to be above the second energy level threshold.

23. The apparatus according to claim 20 further including a state selector to cause the communications system to change to the second communications state if the detected energy level of said at least one signal is determined to be below the second energy level threshold.

24. The apparatus according to claim 19 wherein the detector includes a time slot monitor to monitor an occupancy of time slots used to indicate the request to change states.

25. The apparatus according to claim 24 wherein the detector applies independent thresholds for detection to the time slots.

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

27. The apparatus according to claim 26 wherein the detector causes a request to change communications states in response to detecting energy levels above respective thresholds in both mutually exclusive time slots, and the detector does not cause a request to change communications states in response to detecting energy levels above respective thresholds in fewer than both mutually exclusive time slots.

28. The apparatus according to claim 19 wherein the detector includes a code channel monitor to monitor the occupancy of mutually exclusive code channels.

29. The apparatus according to claim 19 wherein the detector (i) includes at least one integration unit having respective selectable integration times and (ii) sets an energy level threshold based on the energy level of the first energy level.

30. The apparatus according to claim 19 wherein the detector (i) includes an integration unit having a fixed integration time and (ii) sets an energy level threshold based on the transmitted power level of said at least one signal.

31. The apparatus according to claim 19 wherein the first communications state is a standby state and the second communications state is a payload communications state.

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

33. The apparatus according to claim 19 wherein the communications states are data communications states.

34. The apparatus according to claim 19 further including adjusting the second energy level of the signal based on a target probability of detection.

35. The apparatus according to claim 19 further including adjusting the second energy level of the signal based on a target probability of false detection.

46. The method according to claim 30 wherein the wireless communications system is a code division multiple access (CDMA) or orthogonal frequency division multiplexing (OFDM) wireless communications system.

36. 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 at a first energy level and (ii) a second indication for a request to change to a second communications state at a second energy level; and

means for detecting the indications according to alternative criteria.

37. In a wireless 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 having respective energy levels associated with data communications states and detectable according to alternative criteria; and

transmitting the signal including at least one indication.

38. The method according to claim 37 wherein selecting the indications is done according to associated energy levels.

39. The method according to claim 37 wherein transmitting the signal includes multiplexing the indications in time slots in a signaling channel.

40. The method according to claim 39 wherein the energy levels of the indications are selected in a manner considering comparison against independent thresholds by a receiving system.

41. The method according to claim 39 wherein the time slots are mutually exclusive.

42. The method according to claim 41 wherein an indication provided in both mutually exclusive time slots indicates a request to change communications states and an indication provided in fewer than both mutually exclusive time slots indicates a request to remain in the same communications state.

43. The method according to claim 37 wherein transmitting the signal includes applying the indications in mutually exclusive code channels.

44. The method according to claim 37 wherein the criteria include at least one of the following:

code channel time slot occupancy, associated energy level, indication duration, and indication repetition.

45. The method according to claim 37 wherein the communications states include a standby state and a payload communications state.

47. The method according to claim 37 wherein the communications states are data communications states.

48. The method according to claim 37 wherein the respective energy levels of the first and second indications are based on a target probability of detection.

49. The method according to claim 37 wherein the respective energy levels of the first and second indications are based on a target probability of false detection.

50. In a wireless 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 having respective energy levels associated with communications states and detectable according to alternative criteria; and

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

51. The apparatus according to claim 50 further including a multiplexer coupled to the selector and transmitter to apply the indications in time slots in a signaling channel.

52. The apparatus according to claim 51 wherein the energy levels of the indications are selected in a manner considering comparison against independent thresholds by a receiving system.

53. The apparatus according to claim 51 wherein the time slots are mutually exclusive.

54. The apparatus according to claim 53 wherein an indication provided in both mutually exclusive time slots indicates a request to change communications states and an indication provided in fewer than both mutually exclusive time slots indicates a request to remain in the same communications state.

55. The apparatus according to claim 50 wherein the selector applies the indications in mutually exclusive code channels.

56. The apparatus according to claim 50 wherein the criteria include at least one of the following:

code channel time slot occupancy, associated energy level, indication duration, and indication repetition.

57. The apparatus according to claim 50 wherein the communications states include a standby state and a payload communications state.

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

59. The apparatus according to claim 50 wherein the communications states are data communications states.

60. The apparatus according to claim 50 wherein the selector applies the indications to the signal based on a target probability of detection.

61. The apparatus according to claim 50 wherein the selector applies the indications to the signal based on a target probability of false detection.

62. In a wireless 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 having respective energy levels associated with communications states and detectable according to alternative criteria; and

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