Detecting messages transmitted over a communications channel such as a paging channel

• US 5,930,706 A
• Filed: 11/29/1995
• Issued: 07/27/1999
• Est. Priority Date: 11/29/1995
• Status: Expired due to Term

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Raith, Alex Krister
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US08/564,420
• Time in Patent Office: 1,336 Days
• Field of Search: 455/458, 455/38.1, 455/70, 455/343, 455/418, 455/422, 455/31.1, 455/403
• US Class Current: 455/422.1
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention allows for the detection of data contained in transmitted messages (e.g., page messages) at a selected early point in the receiving and decoding process. By forming, at that point, a received data vector (RDV) from the data corresponding to a received message, and by comparing the RDV with one or more test data vectors (TDVs) representing selected relevant or irrelevant data contained in transmitted messages, the receiver (e.g., mobile station) can determine whether the received message contains relevant data which should be fully decoded or irrelevant data which does not need to be fully decoded. In this manner, substantial processing and power savings can be achieved in the receiver.

Claims

1. A method for detecting messages containing various data, said messages being transmitted over a communications channel to a receiver, said method comprising the steps of:

storing in said receiver at least one test data vector (TDV) representing selected data contained in at least one of said messages;

receiving at said receiver data corresponding to one of said messages;

processing said received data to form a received data vector (RDV); and

comparing said RDV to said at least one TDV to determine whether said selected data is contained in said received data.

2. The method of claim 1 further comprising the step of discontinuing processing of said received data if said selected data is determined to be contained in said received data.

3. The method of claim 2 wherein said communications channel is a paging channel (PCH), said receiver is in a mobile station, and said selected data comprises an empty page.

4. The method of claim 3 wherein said selected data further comprises a page to other than said mobile station.

5. The method of claim 2 wherein said RDV is formed before decoding of said received data in said receiver and said step of discontinuing processing of said received data comprises not decoding said received data.

6. The method of claim 1 further comprising the step of continuing processing of said received data if said selected data is determined to be contained in said received data.

7. The method of claim 6 wherein said communications channel is a paging channel (PCH), said receiver is in a mobile station, and said selected data comprises a page to said mobile station.

8. The method of claim 7 wherein said selected data further comprises overhead information.

9. The method of claim 6 wherein said RDV is formed before decoding of said received data in said receiver and said step of continuing processing of said received data comprises decoding said received data.

10. The method of claim 1 further comprising the step of taking at least one specified action if said selected data is determined to be contained in said received data.

11. The method of claim 10 wherein said communications channel is a paging channel (PCH), said receiver is in a mobile station, said selected data comprises a page to said mobile station, and said at least one specified action comprises responding to said page.

12. The method of claim 11 wherein said selected data further comprises overhead information and said at least one specified action further comprises an action indicated in said overhead information.

13. The method of claim 1 wherein said selected data is determined to be contained in said received data if the difference between said RDV and said at least one TDV is below a predetermined threshold.

14. The method of claim 13 wherein said RDV is compared to said at least one TDV using a bitwise XOR operation and said threshold is an integral number of bits.

15. The method of claim 13 wherein said threshold is adjusted to minimize errors in detecting said selected data.

16. The method of claim 13 wherein said threshold is adjusted on the basis of channel quality measurements or estimates.

17. The method of claim 16 wherein said threshold is adjusted on the basis of received signal strength (RSS).

18. The method of claim 16 wherein said threshold is adjusted on the basis of signal-to-noise ratio (SNR).

19. The method of claim 16 wherein said threshold is adjusted on the basis of frame error rate (FER).

20. The method of claim 16 wherein said threshold is adjusted on the basis of bit error rate (BER).

21. A mobile station operating in a communications system which transmits to said mobile station a plurality of different page messages including an empty page message containing no page and a non-empty page message containing one or more pages to one or more mobile stations operating in said system, said mobile station comprising:

means for storing a test data vector (TDV) representative of an empty page message;

means for receiving from said system data corresponding to one of said page messages;

means for processing said received page message data into a received data vector (RDV);

means for comparing said RDV with said empty page TDV to determine whether said received page message data corresponds to an empty page message; and

means for decoding said received page message data.

22. The mobile station of claim 21 wherein said mobile station discontinues processing of said received page message data if it is determined to correspond to an empty page message.

23. The mobile station of claim 21 wherein said mobile station decodes said received page message data if it is determined not to correspond to an empty page message.

24. The mobile station of claim 21 wherein:

said mobile station also stores at least one test data vector (TDV) representative of a non-empty page message containing a specific page to said mobile station;

during predetermined periods said mobile station compares said RDV to said empty page TDV to determine whether said received page message data corresponds to an empty page message; and

during other periods said mobile station compares said RDV to said at least one specific page TDV to determine whether said received page message data corresponds to a non-empty page message containing said specific page.

25. The mobile station of claim 24 wherein during said predetermined periods said mobile station discontinues processing of said received page message data if it is determined to correspond to an empty page message, and decodes said received page message data if it is determined not to correspond to an empty page message.

26. The mobile station of claim 24 wherein during said other periods said mobile station decodes said received page message data if it is determined to correspond to a non-empty page message containing said specific page, and discontinues processing of said received page message data if it is determined not to correspond to a non-empty page message containing said specific page.

27. The mobile station of claim 24 wherein during said other periods said mobile station transmits a page response without decoding said received page message data if it is determined to correspond to a non-empty page message containing said specific page, and discontinues processing of said received page message data if it is determined not to correspond to a non-empty page message containing said specific page.

28. The mobile station of claim 24 wherein said specific page comprises the mobile station identity (MSID) of said mobile station.

29. The mobile station of claim 24 wherein said predetermined periods comprise periods in which most of said page messages transmitted by said system are empty page messages.

30. The mobile station of claim 21 wherein said system transmits each of said page messages in a Layer 2 (L2) frame of data.

31. The mobile station of claim 30 wherein:

said L2 frame includes overhead information having a plurality of different values;

said mobile station also stores at least one test data vector (TDV) representative of one or more selected values of said overhead information; and

said mobile station compares said RDV to said at least one overhead information TDV to determine whether said received page message data corresponds to any of said selected values.

32. The mobile station of claim 31 wherein said mobile station decodes said received page message data if it determined not to correspond to an empty page message or to correspond to any of said selected values, and does not decode said received page message data if it determined to correspond to an empty page message and not to correspond to any of said selected values.

33. The mobile station of claim 31 wherein said mobile station unconditionally decodes said received page message data at predetermined intervals so as to read said selected values.

34. The mobile station of claim 31 wherein one of said selected values indicates a particular mobile station control function and said mobile station executes said control function without decoding said received page message data if it is determined to correspond to said one selected value.

35. The mobile station of claim 31 wherein said L2 frame is formatted according to the IS-136 standard.

36. The mobile station of claim 31 wherein said L2 frame is formatted according to the GSM standard.

37. The mobile station of claim 31 wherein said L2 frame is formatted according to the PDC standard.

38. The mobile station of claim 31 wherein said L2 frame is formatted according to the IS-95 standard.

39. The mobile station of claim 21 wherein said processing means comprises means for demodulating said received page message data.

40. The mobile station of claim 39 wherein said processing means further comprises means for equalizing said demodulated page message data.

41. The mobile station of claim 40 wherein said decoding means comprises means for deinterleaving said equalized page message data.

42. The mobile station of claim 41 wherein said decoding means further comprises means for channel decoding said deinterleaved page message data.

43. The mobile station of claim 42 wherein said decoding means further comprises means for detecting said channel decoded page message data.

44. The mobile station of claim 39 wherein said decoding means comprises means for deinterleaving said demodulated page message data.

45. The mobile station of claim 44 wherein said decoding means further comprises means for channel decoding said deinterleaved page message data.

46. The mobile station of claim 45 wherein said decoding means further comprises means for detecting said channel decoded page message data.

47. The mobile station of claim 21 wherein said receiving and processing means comprise a RAKE receiver.

48. The mobile station of claim 47 wherein said decoding means comprises means for despreading said received page message data.

49. The mobile station of claim 48 wherein said decoding means further comprises means for deinterleaving said despread page message data.

50. The mobile station of claim 49 wherein said decoding means further comprises means for channel decoding said deinterleaved page message data.

51. The mobile station of claim 50 wherein said decoding means further comprises means for detecting said channel decoded page message data.

52. The mobile station of claim 21 wherein said TDV represents less than all of the data in an empty page message and said RDV is processed from less than all of said received page message data.

53. The mobile station of claim 21 wherein said received page message data is determined to correspond to an empty page message if the difference between said RDV and said TDV is below a predetermined threshold and is determined not to correspond to an empty page message if said difference is above said threshold.

54. The mobile station of claim 53 wherein said RDV is compared to said TDV using a bitwise XOR operation and said threshold is an integral number of bits.

55. The mobile station of claim 53 wherein said mobile station is configured to operate in a full decoding mode in which said mobile station unconditionally decodes said received page message data and a refined decoding mode in which said mobile station decodes said received page message data only if it is determined not to correspond to an empty page message, said decoding modes being invoked simultaneously during the receipt of a plurality of page messages by said mobile station, and said threshold being adjusted to minimize decision errors made in said refined decoding mode as compared with said full decoding mode while receiving said messages.

56. The mobile station of claim 53 wherein said threshold is adjusted by said mobile station on the basis of channel quality measurements or estimates.

57. The method of claim 56 wherein said threshold is adjusted on the basis of received signal strength (RSS).

58. The method of claim 56 wherein said threshold is adjusted on the basis of signal-to-noise ratio (SNR).

59. The method of claim 56 wherein said threshold is adjusted on the basis of frame error rate (FER).

60. The method of claim 56 wherein said threshold is adjusted on the basis of bit error rate (BER).

61. A mobile station operating in a communications system which transmits to said mobile station a plurality of different page messages including an empty page message containing no page and a non-empty page message containing one or more pages to one or more mobile stations operating in said system, said mobile station comprising:

means for storing at least one test data vector (TDV) representative of a non-empty page message containing a specific page to this mobile station;

means for receiving from said system data corresponding to one of said page messages;

means for processing said received page message data into a received data vector (RDV);

means for comparing said RDV with said at least one specific page TDV to determine whether said received page message data corresponds to a non-empty page message containing said specific page; and

means for decoding said received page message data.

62. The mobile station of claim 61 wherein said mobile station decodes said received page message data if it is determined to correspond to a non-empty page message containing said specific page.

63. The mobile station of claim 61 wherein said mobile station transmits a page response without decoding said received page message data if it is determined to correspond to a non-empty page message containing said specific page.

64. The mobile station of claim 61 wherein said mobile station discontinues processing of said received page message data if it is determined not to correspond to a non-empty page message containing said specific page.

65. The mobile station of claim 61 wherein:

said mobile station also stores a test data vector (TDV) representative of an empty page message;

during predetermined periods said mobile station compares said RDV to said empty page TDV to determine whether said received page message data corresponds to an empty page message; and

during other periods said mobile station compares said RDV to said at least one specific page TDV to determine whether said received page message data corresponds to a non-empty page message containing said specific page.

66. The mobile station of claim 65 wherein during said predetermined periods said mobile station decodes said received page message data if it is determined not to correspond to an empty page message, and does not decode said received page message data if it is determined to correspond to an empty page message.

67. The mobile station of claim 65 wherein during said other periods said mobile station decodes said received page message data if it is determined to correspond to a non-empty page message containing said specific page, and does not decode said received page message data if it is determined not to correspond to a non-empty page message containing said specific page.

68. The mobile station of claim 65 wherein during said other periods said mobile station transmits a page response without decoding said received page message data if it is determined to correspond to a non-empty page message containing said specific page, and does not decode said received page message data if it is determined not to correspond to a non-empty page message containing said specific page.

69. The mobile station of claim 65 wherein said specific page comprises the mobile station identity (MSID) of said mobile station.

70. The mobile station of claim 65 wherein said predetermined periods comprise periods in which most of said page messages transmitted by said system are empty page messages.

71. The mobile station of claim 61 wherein said system transmits each of said page messages in a Layer 2 (L2) frame of data.

72. The mobile station of claim 71 wherein:

said L2 frame includes overhead information having a plurality of different values;

said mobile station also stores at least one test data vector (TDV) representative of one or more selected values of said overhead information; and

said mobile station compares said RDV to said at least one overhead information TDV to determine whether said received page message data corresponds to any of said selected values.

73. The mobile station of claim 72 wherein said mobile station decodes said received page message data if it determined to correspond to a non-empty page message containing said specific page or to correspond to any of said selected values, and does not decode said received page message data if it determined not to correspond to a non-empty page message containing said specific page and not to correspond to any of said selected values.

74. The mobile station of claim 72 wherein said mobile station unconditionally decodes said received page message data at predetermined intervals so as to read said selected values.

75. The mobile station of claim 72 wherein one of said selected values indicates a particular mobile station control function and said mobile station executes said control function without decoding said received page message data if it is determined to correspond to said one selected value.

76. The mobile station of claim 72 wherein said L2 frame is formatted according to the IS-136 standard.

77. The mobile station of claim 72 wherein said L2 frame is formatted according to the GSM standard.

78. The mobile station of claim 72 wherein said L2 frame is formatted according to the PDC standard.

79. The mobile station of claim 72 wherein said L2 frame is formatted according to the IS-95 standard.

80. The mobile station of claim 61 wherein said processing means comprises means for demodulating said received page message data.

81. The mobile station of claim 80 wherein said processing means further comprises means for equalizing said demodulated page message data.

82. The mobile station of claim 81 wherein said decoding means comprises means for deinterleaving said equalized page message data.

83. The mobile station of claim 82 wherein said decoding means further comprises means for channel decoding said deinterleaved page message data.

84. The mobile station of claim 83 wherein said decoding means further comprises means for detecting said channel decoded page message data.

85. The mobile station of claim 80 wherein said decoding means comprises means for deinterleaving said demodulated page message data.

86. The mobile station of claim 85 wherein said decoding means further comprises means for channel decoding said deinterleaved page message data.

87. The mobile station of claim 86 wherein said decoding means further comprises means for detecting said channel decoded page message data.

88. The mobile station of claim 61 wherein said receiving and processing means comprise a RAKE receiver.

89. The mobile station of claim 88 wherein said decoding means comprises means for despreading said received page message data.

90. The mobile station of claim 89 wherein said decoding means further comprises means for deinterleaving said despread page message data.

91. The mobile station of claim 90 wherein said decoding means further comprises means for channel decoding said deinterleaved page message data.

92. The mobile station of claim 91 wherein said decoding means further comprises means for detecting said channel decoded page message data.

93. The mobile station of claim 61 wherein said TDV represents less than all of the data in a non-empty page message containing said specific page, and said RDV is processed from less than all of said received page message data.

94. The mobile station of claim 61 wherein said received page message data is determined to correspond to a non-empty page message containing said specific page if the difference between said RDV and said at least one TDV is below a predetermined threshold, and is determined not to correspond to a non-empty page message containing said specific page if said difference is above said threshold.

95. The mobile station of claim 94 wherein said RDV is compared to said at least one TDV using a bitwise XOR operation and said threshold is an integral number of bits.

96. The mobile station of claim 94 wherein said threshold is adjusted by said mobile station on the basis of channel quality measurements or estimates.

97. The mobile station of claim 96 wherein said threshold is adjusted on the basis of received signal strength (RSS).

98. The mobile station of claim 96 wherein said threshold is adjusted on the basis of signal-to-noise ratio (SNR).

99. The mobile station of claim 96 wherein said threshold is adjusted on the basis of frame error rate (FER).

100. The mobile station of claim 96 wherein said threshold is adjusted on the basis of bit error rate (BER).

101. The mobile station of claim 61 wherein said RDV is compared to said at least one TDV using a Maximum Likelihood Detection technique.

102. A method for detecting page messages transmitted to a mobile station, each of said page messages being an empty page message containing no page to any mobile station or a non-empty page message containing one or more pages to one or more mobile stations, said method comprising the steps of:

storing in said mobile station a first set of test data vectors (TDVs) representative of an empty page message;

storing in said mobile station a second set of TDVs representative of a non-empty page message containing a specific page for said mobile station;

receiving data corresponding to a transmitted page message;

processing said received page message data to form a received data vector (RDV);

comparing said RDV with said first or second set of TDVs;

if said RDV is being compared with said first set of TDVs, determining whether said received page message data corresponds to an empty page message; and

if said RDV is being compared with said second set of TDVs, determining whether said received page message data corresponds to a non-empty page message containing said specific page.

103. The method of claim 102 further comprising the step of discontinuing processing of said received page message data if it is determined to correspond to an empty page message.

104. The method of claim 102 further comprising the step of decoding said received page message data if it is determined not to correspond to an empty page message.

105. The method of claim 102 further comprising the step of decoding said received page message data if it is determined to correspond to a non-empty page message containing said specific page.

106. The method of claim 102 further comprising the step of transmitting a page response from said mobile station without decoding said received page message data if it is determined to correspond to a non-empty page message containing said specific page.

107. The method of claim 102 further comprising the step of discontinuing processing of said received page message data if it is determined not to correspond to a non-empty page message containing said specific page.

108. The method of claim 102 wherein said first set of TDVs includes one TDV and said second set of TDVs includes a plurality of TDVs.

109. The method of claim 102 wherein said RDV is compared with said first set of TDVs during a first period and compared with said second set of TDVs during a second period.

110. The method of claim 109 wherein said first period comprises off-peak hours in which most transmitted page messages are empty page messages.

111. The method of claim 109 wherein said second period comprises busy hours in which most transmitted page messages are non-empty page messages.

112. The method of claim 109 wherein said mobile station unconditionally decodes said received page message data during a third period.