Ericsson Ge Mobile Communications Inc.

Ericsson Gmbh

Philip C Gulliford

James L Teel, Jr

Wim A Imron

Charles P Brame

Timothy F Cree

Satish Kappagantula

Stephen R Downs

Wim A Improm

A distributed trunked radio frequency (RF) switching network (multisite switch) distributes audio routing control information and digitized audio signals to communications interface modules (nodes) throughout the multisite switch, thus avoiding a centralized mixing matrix, increasing fault tolerance and providing low routing request latency time. Each audio source, (for example, RF repeater transmitter, dispatch console microphone) is preassigned an audio channel on a time division multiplexed (TDM) digitized 'audio network' or bus within the switch. The audio sources continually provide digitized audio signals to all other nodes within the switch over the assigned TDM bus channels. Audio routing is performed at the audio destinations (for example, interface modules/nodes associated with RF repeater receivers, dispatch console speakers) by selectively 'listening' to active TDM network channels. In the preferred embodiment, audio is routed undirectionally on an 'as needed' basis (for example, in response to radio transceiver 'keys' and 'unkeys'), and audio routing pathways may change dynamically during an on-going call.

Audio routing within trunked radio frequency multisite switch

In a multisite radio frequency (RF) signal transmission system, a multisite switch routes audio and data information throughout the system. This switch has a node through which a system manager and system operator can configure and diagnose each site, console and channel in the (RF) system.

RF trunking multisite switch configuration and diagnostics interface

A multisite network switch for a series of RF digital trunked radio transceivers and dispatcher consoles. Each transceiver covers a certain site area. The switch establishes audio communications between different sites and various dispatcher consoles. The multisite switch has a distributed architecture in which each node of the switch is supported by a microprocessor controlled card. Each node interfaces with a site, dispatcher console, system manager or other system component.

Distributed multisite system architecture

A distributed trunked radio frequency (RF) switching network (switch) distributes audio routing control and processing throughout the switch, thus avoiding a centralized mixing matrix, increasing fault tolerance and providing low routing request latency time. Each audio source (e.g., RF repeater transmitter, dispatch console microphone) is preassigned an audio channel on a time division multiplexed (TDM) digitized audio network or bus. The audio sources continually broadcast digitized audio signals to all other nodes over the TDM network. Audio routing is performed at the audio destinations (e.g., nodes associated with RF repeater receivers, dispatch console speakers) by selectively 'listening' to active TDM network channels. In the preferred embodiment, audio is routed unidirectionally on an 'as needed' basis (e.g., in response to radio transceiver 'keys' and 'unkeys'), and audio routing pathways may change dynamically during an on-going call.

A multisite network switch for a series of RF digital trunked radio transceivers and dispatcher consoles. Each transceiver covers a certain site area. The switch establishes audio communications between different sites and various dispatcher consoles. The multisite switch has a distributed architecture in which each node of the switch is supported by a microprocessor controlled card. The nodes are connected by audio buses and a dedicated message bus. The messages on the message bus allow the nodes to communicate control information regarding the status of slots on the audio bus, the members in groups, the location of radio units, call types and a host of other information needed to operate the switch.

Data protocol and monitoring system for RF trunking multisite switch

A multisite network switch for a series of RF digital trunked radio transceivers and dispatcher consoles. The switch establishes audio communications between different sites and various dispatcher consoles. The multisite switch has a distributed architecture in which each node of the switch is supported by a microprocessor controlled card. This card has a communications controller that routes messages between the internal switch bus, an outside port and an interface processor that controls the audio slots in the switch. The communications controller receives control messages from the switch bus, but discards redundant slot status messages by checking a slot status bit map stored in a memory unit on the card.

Message bus slot update/idle control in RF trunking multisite switch

An interface for a conventional base station into a digitally trunked network of RF communications systems acts a pseudo-down link from a multisite switch to a trunked site controller. The interface monitors the conventional channels from the base station and sends a channel assignment message to the multisite switch when it detects a voice signal. The channel assignment message notifies the trunked RF systems that a new call is active so that each system can assign a trunked working channel to the conventional call. Similarly, the multisite switch sends a channel request when a trunked call is to be broadcast over a conventional channel. The interface keys the channel and couples the channel to the trunked call.

Conventional base station interface architecture for RF trunking

A radio frequency (RF) signal transmission system is interconnected by a multisite switch that routes command and audio transmission signals between the RF systems. The multisite switch has a distributed architecture of nodes wherein each node is coupled to one of the RF systems, such as a site controller or dispatcher console. Each of the switch nodes has a common architecture in which a single controller board operates a plurality of audio boards. In addition, the controller board has two principal processors that communicate with each other via a dual-port RAM.

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Forest, VA, United States of America

Philip C Gulliford