Method of setting radio transmitters for synchronous radio transmission

• US 4,709,401 A
• Filed: 09/29/1986
• Issued: 11/24/1987
• Est. Priority Date: 12/09/1982
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Akerberg, Dag E.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): KUNTZ, CURTIS A
• Application Number:
  US06/912,983
• Time in Patent Office: 421 Days
• Field of Search: 455/18, 455/51, 455/53, 455/57, 455/75, 340/825.44
• US Class Current: 455/503
• CPC Class Codes: G08B 3/1016 using wireless transmission calling systems using transmission by inductive loop H04B5/00
• CPC Class Codes: H04H 20/67 Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency

Abstract

In a radio paging system wherein paging calls are initiated by a central radio station and sent over lines to subordinate radio stations for transmission to paging devices, the subordinate stations are synchronized to transmit paging messages by introducing time delays between reception of a message from the central radio station before transmission, the time delays being functions of the message transmit times via the lines to the various other stations as well as the radio propogation time between the other stations.

Claims

1. In a transmission system having a central radio station and a plurality of other radio stations connected by lines to the central station, wherein each of the stations includes a transmitter for transmitting to receiving devices, the method of setting, before transmission by a plurality of the radio stations of messages generated by the central station, for synchronizing the operation of a first of said other stations to a second of said other stations at least comprising the steps of:

the central station sending on lines to said first and second other stations an order message to set for simultaneous transmission, each of said first and second other stations noting the time of receipt of said order message, said second other station radio transmitting said order message a first given period of time after the receipt thereof, said first other station noting and storing the time of arrival of said order message over the air from said second other station, said first station establishing the delay time of transmission over the air of a subsequent message received on a line, said established delay time being the difference between the time of reception via the line of said order message from the central station and the time of reception of said order message over the air from the second other station less the propogation time, stored in the first other station, for a message to be transmitted over the air from said second other station to said first other station.

2. The method of claim 1 wherein the further other stations are set in the same manner as claim 1 consecutively in the order of distance from the central station.