Synchronized, multitransmitter, single frequency paging system

• US 4,506,384 A
• Filed: 12/20/1982
• Issued: 03/19/1985
• Est. Priority Date: 12/20/1982
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Lucas, Alfred R.
• Primary Examiner(s): Bookbinder, Marc E.
• Application Number:
  US06/450,871
• Time in Patent Office: 820 Days
• Field of Search: 455/53, 455/54, 455/56-58, 455/51, 455/88, 179/2 EC, 340/825.21, 340/825.5
• US Class Current: 340/7.3
• 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
• CPC Class Codes: H04W 84/022 One-way selective calling networks, e.g. wide area paging

Abstract

The invention is a synchronized communication system for effectively transmitting messages to a remote mobile receiver where the system includes a plurality of transmitters operating on a single RF communication channel. The system includes a central wide area transmitter which transmits messages over a wide area. The system also includes a plurality of local transmitters which transmit messages over a local area within the wide area served by the wide area transmitter. The transmitters of the system are coordinated by a synchronization link which allows the central wide area transmitter to be keyed only when the local transmitters are not keyed. Correspondingly the synchronization link only allows the local transmitters to be keyed when the central wide area transmitter is not keyed. Normally the synchronization link keys and dekeys the central wide area transmitter and local transmitters in a normal timing cell pattern. If the central wide area transmitter builds up a backlog of messages, the synchronization link may interrupt the normal timing cell and reduce the backlog by holding the central wide area transmitter keyed for an extended period of time.

Claims

1. A synchronized communication system for effectively transmitting messages to a plurality of remote mobile receivers wherein said system operates on a single RF communication channel, said system comprising,

a central wide area transmitter which transmits messages to the plurality of mobile receivers,

a plurality of localized transmitters within the wide area which transmits messages to the plurality of mobile receivers,

a synchronization link between said central wide area transmitter and said plurality of localized transmitters to create a master-slave relationship wherein said plurality of localized tramsmitters is keyed simultaneously and only when said central wide area transmitter is not keyed.

2. A synchronized communication system according to claim 1 wherein said synchronization link creates a master-slave relationship wherein said plurality of localized transmitters is dekeyed whenever said central wide area transmitter is keyed.

3. A synchronized communication system according to claim 1 wherein the plurality of mobile receivers has a time window associated with its response to a message transmission from said plurality of localized transmitters wherein during said time window said synchronization link dekeys said plurality of localized transmitters and keys said central wide area transmitter.

4. A synchronized communication system according to claim 1 wherein said synchronization link normally follows a keying and dekeying sequence of keying said plurality of localized transmitters to transmit a tone and voice address, dekeying said plurality of localized transmitters, keying said central wide area transmitter to transmit at least one set of data or tones, dekeying, said central wide area transmitter, keying said plurality of localized transmitter to transmit a voice message.

5. A synchronized communication system according to claim 4 wherein said synchronization link will interrupt said normal sequence to cause said central wide area transmitter to remain keyed in order to transmit a plurality of messages in response to an indication from said central wide area transmitter that a backlog of data or tones are awaiting transmission.

6. A synchronized communication system according to claim 1 wherein said synchronization link normally follows a keying and dekeying sequence of keying said central wide area transmitter to transmit a tone and voice address, dekeying said central wide area transmitter, keying said plurality of localized transmitters to transmit at least one set of data or tones, dekeying said plurality of localized transmitters, keying said central wide area transmitter to transmit a voice message.

7. A synchronized communication system according to claim 6 wherein said synchronization link will interrupt said normal sequence to cause said plurality of localized transmitters to remain keyed in order to transmit a plurality of messages in response to an indication from said localized transmitter that a backlog of data or tones are awaiting transmission.

8. A method of effectively transmitting messages on a single channel in a synchronized communication system including a plurality of remote mobile receivers, a central wide area transmitter and a plurality of localized transmitters within the wide area, the method comprising the sequential steps of;

(a) simultaneously keying said localized transmitters and transmitting a local address to the mobile receiver,

(b) dekeying said localized transmitters,

(c) keying said central wide area transmitter for a predetermined time period and transmitting a wide area address and message to the mobile receivers,

(d) dekeying said central wide area transmitter,

(e) keying said localized transmitters and transmitting a message to the mobile receivers addressed in step a.

9. A method according to claim 8 wherein the central wide area transmitter remains in a keyed position for a time period greater than said predetermined time period if a backlog of wide area messages are awaiting transmission.

10. A method of effectively transmitting messages on a single channel in a synchronized communication system including a plurality of remote mobile receivers, a central wide area transmitter and a plurality of localized transmitters within the wide area, said method comprising the sequential steps of:

(a) keying said central wide area transmitter and transmitting an address to the mobile receivers,

(b) dekeying said central wide area transmitter,

(c) simultaneously keying said localized transmitters for a predetermined time period and transmitting a local address and message to the mobile receivers,

(d) simultaneously dekeying said localized transmitters,

(e) keying said central wide area transmitter and transmitting a message to the mobile receivers addressed in step a.

11. A method according to claim 10 wherein the localized transmitters remain in a keyed position for a time period greater than said predetermined time period if a backlog of local messages are awaiting transmission.