Processor-to-processor communications protocol for a public service trunking system

• US 5,020,132 A
• Filed: 03/06/1989
• Issued: 05/28/1991
• Est. Priority Date: 08/14/1987
• Status: Expired due to Term

• Current Assignee: Com-Net Ericsson Canada Corp., Com-Net Ericsson Critical Radio Systems, Inc.
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Nazarenk, Dimitri M., Yurman, Bruno, Hughes, Houston H. III, Hattey, David L., Gordon, Robert T.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Faile, Andrew
• Application Number:
  US07/365,810
• Time in Patent Office: 813 Days
• Field of Search: 455/33-34, 455/17, 455/54, 455/56, 375/4, 370/97, 379/58-63
• US Class Current: 455/17
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04W 4/10 Push-to-Talk [PTT] or Push-On-Call services
• CPC Class Codes: H04W 76/45 for Push-to-Talk [PTT] or Push-to-Talk over cellular [PoC] services
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

A downlink between a communications dispatch console and a digitally trunked radio repeater system site controller efficiently transfers message data between the site controller and the console over a standard 9.2 kilobit per second landline. A downlink trunking card identical in structure to trunking cards used in the preferred embodiment system for RF channel signal processing interfaces the site controller with the landline link. A similar trunking card on the other side of the landline link interfaces the dispatch console processor with the landline link. Message protocol and format is translated between the site controller and the landline link and between the landline link and the dispatch console. Data buffering at each end of the landline link maximizes data transfer rate over the landline, and in addition, a priority scheme insures that more important messages are transmitted over the downlink before less important messages. Retransmit-until-acknowledged protocol is used to insure reliable message transfer--and also to permit receiving units along the downlink to slow down transmitting units in order to avoid message traffic blockage.

Claims

1. In a trunked radio repeater system having an architecture of a site controller communicating with RF repeater means and a downlink trunking card module, said RF repeater means and downlink trunking card module each having control functions and being capable of communicating with each other independently of the site controller, a method of communicating digital signals over a downlink between said site controller located at an RF repeater site and a processor located remotely from said site, said RF repeater site including a plurality of said RF repeater means for communicating digital control signals with mobile radio units over RF channels using a predefined digital signalling protocol, said method comprising the steps of:

(1) communicating digital signals in a first predefined protocol between said site controller and said downlink trunking card module over a first serial data link;

(2) translating said first protocol digital signals between said first protocol and a second predefined protocol with said downlink trunking card module;

(3) communicating said digital signals in said second protocol between said downlink trunking card module and a switch trunking card module located remotely from said site over a second serial data link;

(4) translating said second protocol digital signals between said second protocol and a third predefined protocol with said switch trunking card module; and

(5) communicating said third protocol digital signals between said switch trunking card module and said processor over a third serial data link,

wherein said first and second protocols are different from one another, and said second protocol is substantially identical to the signalling protocol used to communicate digital control signals between said repeater means and said mobile radio units over said RF channels.

2. A method as in claim 1 wherein:

said communicating step (1) includes transmitting digital data signals over said first data link at a rate of about 19.2 kbps using said first protocol;

said communicating step (5) includes transmitting digital data signals over said third data link at a rate of about 19.2 kbps using said third protocol; and

said communicating step (3) includes transmitting digital data signals over said second data link at a rate of about 9.6 kbps using said second protocol.

3. A method as in claim 1 wherein:

said communicating step (3) includes transmitting data over said second data link at a first data transfer rate; and

said communicating steps (1) and (5) include transmitting data over said first and third data links, respectively, at data transfer rates which are substantially greater than said first data transfer rate.

4. A method as in claim 1 further including the steps of:

performing said steps (1)-(5) in sequence to communicate global messages between said controller and said processor; and

performing only said steps (1) and (2) to communicate administrative messages between said controller and said downlink trunking card module.

6. A method as in claim 1 further including the steps of:

performing said steps (1)-(5) in sequence to communicate global messages between said controller and said processor; and

performing only said steps (4) and (5) to communicate administrative messages between said processor and said switch trunking card module.

5. In a digitally trunked radio frequency communications system, an arrangement for prioritizing digital messages for communication between a dispatch console and a site controller, said arrangement including:

means for receiving control channel messages, working channel messages, patch messages, and administrative messages from said dispatch console;

buffer means connected to said receiving means for temporarily storing said received messages;

communication link means connected to said buffer means for transmitting messages contained in said buffer means to said site controller; and

processing means, operatively connected to said buffer means and said communication link means, for prioritizing the transmission of messages temporarily stored by said buffer means so that;

(a) all stored control channel messages are transmitted before any stored working channel, patch or administrative message, (b) all stored working channel messages are transmitted before any stored patch and administrative message, and (c) all stored patch messages are transmitted before any stored administrative message.

7. In a trunked radio repeater system having an architecture of a site controller communicating with RF repeater means and a downlink trunking card module, said RF repeater means and downlink trunking card module each having control functions and being capable of communicating with each other independently of the site controller, a method of communicating digital signals over a downlink between said site controller located at an RF repeater site and a processor located remotely from said site, said RF repeater site including a plurality of RF repeater means for communicating digital control signals with mobile radio units over RF channels using a predefined digital signalling protocol, said method comprising the steps of:

(1) communicating digital signals in a first predefined protocol between said site controller and said downlink trunking card module over a first serial data link;

(2) translating said first protocol digital signals between said first protocol and a second predefined protocol with said downlink trunking card module;

(3) communicating said digital signals in said second protocol between said downlink trunking card module and a switch located remotely from said site over a second serial data link;

(4) translating said second protocol digital signals between said second protocol and a third predefined protocol with said switch; and

(5) communicating said third protocol digital signals between said switch and said processor over a third serial data link,

wherein said first and second protocols are different from one another, and said second protocol is substantially identical to the signalling protocol used to communicate digital control signals between said repeater means and said mobile radio units over said RF channels.