Missing radio page message detection

• US 5,159,331 A
• Filed: 06/06/1990
• Issued: 10/27/1992
• Est. Priority Date: 06/06/1990
• Status: Expired due to Term

• Current Assignee: Protocol-ip.com, LLC, Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Corporation and Seiko Epson Corporation
• Inventors: Macchio, Henry A., Park, Michael C.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): WEISSMAN, PETER
• Application Number:
  US07/534,207
• Time in Patent Office: 874 Days
• Field of Search: 340/825.44, 340/825.34, 455/32, 455/38, 379/57, 379/63, 371/32, 371/33, 371/69.1
• US Class Current: 340/7.44
• CPC Class Codes: G04G 21/04 using radio waves radio-controlled time-pieces G04R
• CPC Class Codes: H04W 88/023 with message or information receiving capability

Abstract

A paging system transmits consecutively numbered page messages to receivers. Receivers detect missing page messages by interrogation of received page message numbers, and a missing page message is indicated by a gap in received page message numbers. However, page messages may be separated by long time intervals and a gap in received message numbers can not be detected until a subsequent page message is received. To more immediately detect a missing page message, a sequence message generated by the paging system provides a last transmitted page message number to receivers during otherwise unused portions of the transmission bandwidth. The receivers can thereby detect missing page messages without waiting until receiving a subsequent page message and without depleting the transmission bandwidth resource.

Claims

1. In a paging system transmitting consecutively numbered page messages which include paging information to a selected receiver adapted to detect missing messages by interrogation of received message numbers,, an improved method of detecting at said receiver missing transmitting page messages comprising:

maintaining at said receiver a first number corresponding to the message number of the last receiver page message;

transmitting to said receiver and receiving at said receiver a sequence message, which is in addition to the normally transmitted information bearing page messages said sequence message including a second number corresponding to the last page message transmitted to said receiver; and

upon receiving a sequence message, comparing at said receiver the first number with the second number of the received sequence message, a difference in said numbers indicating a missing page message.

2. In a paging system, a method of detecting missed messages comprising:

receiving a plurality of page messages for a selected receiver;

inserting into each of said page messages a message number corresponding to a position in an ordered transmission sequence;

transmitting to said selected receiver said plurality of page messages in said ordered transmission sequence;

maintaining a last transmitted number corresponding to the message number of the most recent page message transmitted to said selected receiver;

transmitting to said selected receiver a plurality of sequence messages each containing said last transmitted number;

receiving page messages at said selected receiver;

maintaining within said receiver a last received number corresponding to the message number of the page message most recently received;

receiving sequence messages at said receiver;

comparing said last received number maintained by said receiver to the last transmitted number of each received sequence message; and

detecting within said receiver a missed message when the compared last received number fails to correspond to the compared last transmitted number.

3. The system according to claim 2 wherein transmitting said plurality of sequence messages is intermingled with transmitting of said page messages.

4. The system according to claim 2 wherein said sequence messages are transmitted in otherwise unused portions of a transmission bandwidth.

5. In a paging system for directing page messages which include page information to a plurality of receivers by transmission facilities providing successive message frames each comprising a plurality of time slots wherein each receiver is associated with a time slot, page messages for each receiver are transmitted during the associated time slot, and page messages directed to each receiver are consecutively numbered whereby each receiver detects missing page messages by interrogation of received page message numbers, an improved method of detecting missing page messages comprising:

associating at said transmission facility a last transmitted number with a given receiver, the last transmitted number corresponding to the message number of the last message transmitted to said given receiver;

detecting at said transmission facility an unused time slot associated with said given receiver;

transmitting to said given receiver a sequence message which does not include any of said page information during said unused time slot, said sequence message including the last transmitted number associated with said given receiver;

maintaining at said given receiver a last received number corresponding to the last received page message number;

comparing at said given receiver the maintained last received number to the last transmitted number of a received sequence message;

whereby if a difference is detected by said comparing step it indicates a missing page message.