Method for initiating and determining simulcast transmission of a message

• US 5,485,632 A
• Filed: 05/28/1993
• Issued: 01/16/1996
• Est. Priority Date: 02/26/1993
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Ng, Richard, Grube, Gary W., Shaughnessy, Mark L.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): TO, DORIS HA
• Application Number:
  US08/069,045
• Time in Patent Office: 963 Days
• Field of Search: 455/51.2, 455/51.1, 455/54.1, 455/54.2, 455/33.1, 455/54.2, 455/67.1, 455/69, 375/107, 375/109, 375/110, 375/356, 375/358, 375/359
• US Class Current: 455/503
• CPC Class Codes: H04H 20/67 Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency

Abstract

Processing of message transmissions from any node in a simulcast multi-site communication system (100) begins when an initiating communication unit requests (400) to transmit a message to one or more network transceivers. After the request has been assigned by a call processing controller, the initiating unit transports (401) a time stamp message to each transceiver via a digital communication network (202). Each transceiver, after receiving the time stamp message, calculates (402) an outbound delay time and transports the outbound delay time to the initiating unit via the digital communication network. From the outbound delay time, the initiating unit calculates (406) a launch time, wherein the launch time accommodates the worst case expected transport delay through the digital communication network. The message to be transmitted and the launch time is transported to each of the transceivers, such that each transceiver simultaneously transmits the message at the launch time.

Claims

1. In a simulcast communication system that includes a plurality of sites, a time reference, at least two transceivers, a plurality of communication units, a call processing controller, and an external network gateway, wherein each site of the plurality of sites includes at least one receiver or a transceiver of the at least two transceivers, wherein the plurality of sites are operably linked together, to the call processing controller, and to the external network gateway by a non-star topology digital communication network, and wherein the external network gateway operably couples the simulcast communication system to an external communication system, a method for simulcast transmission of a message and simulcast transmission of a subsequent responsive message, the method comprises the steps of;

a) initiating a message transmission request by a first initiating unit, wherein the first initiating unit is one of a set of the external network gateway, the call processing controller, a transceiver of the at least two transceivers, and a receiver of the at least one receiver in each site;

b) at the first initiating unit, upon receiving a call assignment, transporting a first time stamp message to each of the at least two transceivers via the non-star topology digital communication network;

c) upon receiving the first time stamp message, calculating, by the at least two transceivers, a first outbound delay time, wherein the first outbound delay time is based on the first time stamp message and time when the first time stamp message was received;

d) transporting, by each of the at least two transceivers, the first outbound delay time to the first initiating unit;

e) upon receiving the first outbound delay time from each of the at least two transceivers, calculating, by the first initiating unit, a first launch time based on the first outbound delay time from each of the at least two transceivers;

f) transporting, by the first initiating unit, the first launch time and the message to the at least two transceivers, via the non-star topology digital communication network, wherein the at least two transceivers transmit the message at the first launch time;

g) upon completion of transporting the message, by the first initiating unit, initiating a subsequent responsive message transmission request by a second initiating unit, wherein the second initiating unit is one of a set of the external network gateway, the call processing controller a transceiver of the at least two transceivers, a receiver of the at least one receiver in each site, and wherein the second initiating unit is different than the first initiating unit;

h) at the second initiating unit, upon receiving a subsequent responsive call assignment, transporting a second time stamp message to each of the at least two transceivers via the non-star topology digital communication network;

i) upon receiving the second time stamp message, calculating, by the at least two transceivers, a second outbound delay time, wherein the second outbound delay time is based on the second time stamp message and time when the second time stamp message was received;

j) transporting, by each of the at least two transceivers, the second outbound delay time to the second initiating unit;

k) upon receiving the second outbound delay time from each of the at least two transceivers, calculating, by the second initiating unit, a second launch time based on the second outbound delay time from each of the at least two transceivers; and

l) transporting, by the second initiating unit, the second launch time and the subsequent responsive message to the at least two transceivers, via the non-star topology digital communication network, wherein the at least two transceivers transmit the subseouent responsive message at the second launch time,

2. The method of claim 1, wherein the calculation of the first outbound delay time of step (c) further comprises calculating the first outbound delay time to be substantially equal to difference between the first time stamp message and the time when the first time stamp message was received, and wherein the calculation of the second outbound delay time of step (i) further comprises calculating the second outbound delay time to be substantially equal to difference between the second time stamp message and the time when the second time stamp message was received.

3. The method of claim 1, wherein the calculation of the first launch time of step (e) further comprises calculating the first launch time to be substantially equal to the first outbound delay time of a transceiver of the at least two transceivers having a greatest first outbound delay time, and wherein the calculation of the second launch time of step (k) further comprises calculating the second launch time to be substantially equal to the second outbound delay time of a transceiver of the at least two transceivers having a greatest second outbound delay time.

4. In a simulcast communication system that includes a plurality of sites, a time reference, at least two transceivers, a plurality of communication units, a call processing controller, and an external network gateway, wherein each site of the plurality of sites includes at least one receiver or a transceiver of the at least two transceivers, wherein the plurality of sites are operably linked together, to the call processing controller, and to the external network gateway by a non-star topology digital communication network, and wherein the external network gateway operably couples the simulcast communication system to an external communication system, a method for a first initiating unit to initiate a simulcast transmission of a message, followed by a second initiating unit initiating a simulcast transmission of a subsequent responsive message, the method comprises the steps of:

a) initiating a message transmission request by the first initiating unit, wherein the first initiating unit is one of a set of the external network gateway, the call processing controller, a transceiver of the at least two transceivers, and a receiver of the at least one receiver in each site;

b) at the first initiating unit, upon receiving a call assignment, transporting a first time stamp message to each of the at least two transceivers via the non-star topology digital communication network;

c) receiving, by the first initiating unit, a first outbound delay time from each of the at least two transceivers;

d) calculating, by the first initiating unit, a first launch time based on the first outbound delay time from each of the at least two transceivers;

e) transporting, by the first initiating unit, the first launch time and the message to the at least two transceivers, via the non-star topology digital communication network, wherein the at least two transceivers transmit the message at the first launch time;

f) upon completion of transporting the message, by the first initiating unit, initiating a subsequent responsive message transmission request by a second initiating unit, wherein the second initiating unit is one of a set of the external network gateway, the call processing controller, a transceiver of the at least two transceivers, a receiver of the at least one receiver in each site, and wherein the second initiating unit is different than the first initiating unit;

g) at the second initiating unit, upon receiving a subsequent responsive call assignment, transporting a second time stamp message to each of the at least two transceivers via the non-star topology digital communication network;

h) receiving, by the second initiating unit, a second outbound delay time from each of the at least two transceivers;

i) calculating, by the second initiating unit, a second launch time based on the second outbound delay time from each of the at least two transceivers; and

j) transporting, by the second initiating unit, the second launch time and the subsequent responsive message to the at least two transceivers, via the non-star topology digital communication network, wherein the at least two transceivers transmit the subsequent responsive message at the second launch time.

5. The method of claim 4, wherein the calculation of the first launch time of step (d) further comprises calculating the first launch time to be substantially equal to the first outbound delay time of a transceiver of the at least two transceivers having a greatest first outbound delay time, and wherein the calculation of the second launch time of step (j) further comprises calculating the second launch time to be substantially equal to the second outbound delay time of a transceiver of the at least two transceivers having a greatest second outbound delay time.