Extended trunked RF communications systems networking

• US 5,699,353 A
• Filed: 11/24/1993
• Issued: 12/16/1997
• Est. Priority Date: 11/24/1993
• Status: Expired due to Term

• Current Assignee: Pine Valley Investments, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: Ericsson GE Mobile Communications Inc (Telefonaktiebolaget LM Ericsson)
• Inventors: Kent, James S.
• Primary Examiner(s): TON, DANG T
• Application Number:
  US08/156,785
• Time in Patent Office: 1,483 Days
• Field of Search: 370/85.11, 370/95.1, 370/85.9, 370/67, 370/85.7, 370/68.1, 370/95.3, 370/274, 370/278, 370/280, 370/284, 370/310, 370/312, 370/314, 370/315, 370/319, 370/321 , 370/323, 370/324, 370/338, 370/341, 370/346, 370/347, 370/349, 370/376, 370/385, 370/387, 370/389, 370/438, 370/451, 370/493, 370/501, 370/502, 370/503, 370/105.1 , 370/110.1, 370/100.1, 455/94.2, 455/54.1, 455/54.2, 455/34.1, 455/34.2, 455/57.1, 455/58.1, 455/11.1, 455/33.1, 455/33.2, 455/51.1, 455/56.1, 375/3, 375/106, 375/107, 375/211, 375/216, 375/355, 375/356, 379/4, 379/59, 379/60, 379/62
• US Class Current: 370/315
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

In a trunked communications network, a multiple site information distribution control "switch" (multisite switch) provides access to digitized audio and control signals from various audio sources to one or more audio destinations connected at various "nodes" in the multisite switch. A dedicated Network Interface Module (NIM) is provided in the multisite switch to facilitate interconnection and communication between multiple networks of similar multisite switch controlled architectures to create an "extended" mega-network. The NIM allows an entire remote network to appear as a just another multisite switch node in a local network and vice versa. A trunked communications network having a NIM can communicate through this "node" with other networks having a NIM, thus establishing inter-network communications in a manner that is essentially transparent to users in either network. The use of a plurality of NIMs per multisite network allows connection of multiple networks together, for example, in a "star" or series configuration, to greatly expand geographic coverage.

Claims

1. In a first multisite digitally trunked radio frequency communications network including plural repeater sites supporting digitally encoded communications, having corresponding coverage areas and serving mobile or portable digitally trunked radio transceivers disposed within the coverage areas, a distributed control multisite switch for routing communications data between and among repeater sites and other types of analog and digital communications data sources and destinations within said network wherein said communications data includes audio signals and control messages, comprising:

a plurality of interconnected communications interface modules, each module comprising circuitry for passing communications data between particular sources and destinations within said network;

an audio signal bus and a control message bus interconnecting said interface modules, and

at least one network interface module interconnected through the audio signal bus and control message bus with said communications interface modules, said network interface module comprising circuitry for transferring and receiving communications data to and from a second multisite network including a control link operatively connected to the second multisite network for transferring control messages between the control message bus and the second multisite network, and an audio link for transferring audio signals between the audio signal bus and the second multisite network, and said network interface module including a processing circuit for selecting audio signals from the audio signal bus to transfer to the second network via the audio link based on control messages received from the control message bus.

2. A distributed control multisite switch in a first digitally trunked network, as set forth in claim 1, said first digitally trunked network being electronically linked to one or more separate networks each also including a distributed control multisite switch comprising at least one network interface module.

3. A distributed control multisite switch in a first digitally trunked network, as set forth in claim 1, further comprising a plurality of network interface modules, wherein said first digitally trunked network operates as a central network in a star configuration of interconnected networks, and each of said interconnected networks has at least one network interface module.

4. A method for permitting the interfacing of two or more digitally trunked radio frequency communications networks, each network including at least one repeater site supporting digitally encoded communications, having a corresponding coverage area and serving mobile or portable digitally trunked radio transceivers disposed within the coverage area, and each including a distributed control multisite switch having audio bus and a control message bus for routing communications between and among repeater sites and other communications data sources and destinations within the network, comprising steps of:

a) monitoring the control message bus for control messages of all calls routed by a multisite switch of a first network, identifying calls designated for another network based on the control messages, and routing audio signals of the calls designated for another network to an internetwork communications link connected between said multisite switch of said first network and another multisite switch located in a second network;

b) searching for and selecting an available communications data channel on said internetwork link; and

c) alerting all call destinations in said first network via the control bus of said multisite switch of said first network to the presence of incoming audio signal calls from the another network on said internetwork link.

5. A multiple multisite network arrangement forming an extended coverage area communications system, comprising:

a first multisite network of one or more communication units for conducting analog and/or digital communications including a digitized-audio switching arrangement comprising a digitized-audio signal network bus and a digital serial channel message network bus for routing communications between digital repeater sites and other analog/digital communication sources/destinations within said first network;

an internetwork link comprising at least one internetwork digitized-audio signal channel and an internetwork digital control message communications channel;

said first network further comprising one or more dedicated network interface modules connected to said digitized-audio signal network bus, said digital serial channel message network bus, and said internetwork link for communicating both digitized-audio information and digital control message information to/from another digitized-audio switching arrangement associated with a second multisite network, said modules each including a processing circuit for selecting audio signals from the digitized-audio signal network bus and the internetwork link to transfer to/from a second multisite network based on control messages received from the digitized serial channel message network bus and the internetwork link;

wherein a network interface module enables a second network to function as another node on said first network to provide internetwork communications that are essentially transparent to a user of either network effectively resulting in an extended coverage area communications system.

6. An extended communications system according to claim 5, wherein a digitized-audio switching arrangement associated with said second network includes at least one network interface module and is electronically linked to said first network via a network interface module at each network.

7. An extended communications system according to claim 5, further comprising at least second and third networks electronically linked to said first network via a network interface module at each network, said first network acting as a central network in a star configuration of interconnected networks, wherein said first network includes multiple network interface modules for interfacing to a plurality of networks.

8. An extended communications system according to claim 5, wherein said second multisite network includes at least one network interface module coupled to said internetwork link.

9. An extended communications system according to claim 5, further comprising at least second and third multisite networks, each having at least one network interface module and each communicating with said first multisite network via separate internetwork links, said first network acting as a central network in a star configuration of interconnected networks, wherein said first network includes a plurality of network interface modules for interfacing to a plurality of multisite networks such that each of said multisite networks appears as a single node on said first multisite network.

10. In a first digitally trunked radio frequency communications system including multiple RF transceiving sites for establishing radio contact with mobile and/or portable radio transceivers via trunked RF communications channels based on received and transmitted trunking control signals, a distributed control audio signal multisite switch routing audio signals between said multiple RF transceiving sites, said multisite switch comprising:

at least one multiplexed digitized-audio signal bus;

a message network for communicating trunking control messages; and

at least one internetwork interface controller in communication with a second digitally trunked radio frequency communications system, said internetwork interface controller for;

(a) applying audio signals received from said digitized-audio signal bus for routing to an internetwork bus connecting the internetwork controller in said first digitally trunked radio frequency communications system with an second internetwork interface controller in said second digitally trunked radio frequency communications system;

(b) applying trunking control messages to said internetwork bus based on digital trunking signals received from said message network in the first digitally trunked radio frequency communications system;

(c) receiving trunking control messages and audio signals from said internetwork bus; and

(d) autonomously determining whether to route from the digitized-audio signal bus to the internetwork bus the audio signals received in step (a) based at least in part on said trunking control signals received by said step (c).