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

• US 5,253,253 A
• Filed: 02/22/1991
• Issued: 10/12/1993
• Est. Priority Date: 02/22/1991
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Gulliford, Philip C., Kappagantula, Satish, Brame, Charles P., Cree, Timothy F., Imron, Wim A., Teel, James L. Jr.
• Primary Examiner(s): Chin, Wellington
• Application Number:
  US07/658,640
• Time in Patent Office: 963 Days
• Field of Search: 370/85.9, 370/85.11, 370/67, 370/85.7, 370/95.1, 370/68.1
• US Class Current: 370/341
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

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.

Claims

1. A method for processing audio slot status messages in a switch having a distributed architecture of nodes including at least one primary node, and said nodes operatively coupled to a message bus and one or more audio buses, and wherein each node comprises a controller and an associated memory unit having a bit map of a plurality of audio slots on said one or more audio buses, said method comprising the steps of:

a. broadcasting on the message bus a slot assignment message when said primary node assigns a slot from said plurality of audio slots to an audio communication, the slot assignment message identifying the slot being assigned;

b. each node receiving the slot assignment message modifying its bit map to indicate the assignment of the slot identified in the slot assignment message;

c. broadcasting on the message bus one or more slot update messages identifying the assigned slot;

d. each node, upon receiving the slot update message, accessing its bit map and determining whether the bit corresponding to the assigned slot indicates that the slot is assigned;

e. each node having a bit map that indicates the slot is assigned discarding the slot update message,

f. each node having a bit map that indicates the bus/slot is not assigned, modifying its bit map to indicate the assignment of the slot identified in the slot assignment message.

2. A method for processing audio slot status messages in a switch having a distributed architecture of nodes operatively coupled to a message bus and one or more audio buses, at least one of said nodes being a primary node for connecting incoming audio signals to said one or more audio buses, and wherein each node comprises an interface processor, a communications controller and an associated memory unit accessible by the controller and processor and the memory having a bit map of audio slots in said one or more audio buses, said method comprising the steps of:

a. broadcasting on the message bus a slot assignment message when said primary node assigns a slot from said plurality of audio slots to an audio communication, the slot assignment message identifying the slot being assigned;

b. each node receiving the slot assignment message modifying its bit map to indicate the assignment of the slot identified in the slot assignment message;

c. broadcasting on the message bus one or more slot update message identifying the assigned slot;

d. the communications controller at each node receiving the slot update message, and accessing the bit map to determine whether the bit corresponding to the identified slot indicates that the slot is assigned;

e. if the bit map indicates that the identified slot is assigned, then the communications controller discards the slot update message, and

f. if the bit map indicates that the slot is not assigned, then the communications controller sends the slot update message to its associated interface processor.

3. A method as in claim 2 wherein steps b and f further comprise the interface processor modifying the bit map to indicate that the identified bus/slot is assigned.

4. A method for processing audio slot status messages in a switch having a distributed architecture of nodes operatively coupled to a message bus and one or more audio buses, wherein each node includes a processor and a memory, said method comprising the steps of:

a. broadcasting on the message bus a slot assignment message identifying a slot in said one or more audio buses assigned to a particular audio communication;

b. each node receiving the slot assignment message modifying a bit map in memory to indicate the assignment of the slot identified in the slot assignment message.

5. A method for processing audio slot status messages in a switch having a distributed architecture of nodes operatively coupled to a message bus and one or more audio buses, at least one of said nodes being a primary node for connecting incoming audio signals to said one or more audio buses, and wherein each node comprises an interface processor, a communications controller and an associated memory unit accessible by the controller and processor and the memory having a bit map of audio slots, said method comprising the steps of:

a. broadcasting on the message bus a slot assignment message when said primary node assigns a slot on one of said one or more audio buses to an audio communication, the slot assignment message identifying a slot in said one or more audio buses being assigned;

b. each node receiving the slot assignment message modifying its bit map to indicate the assignment of the slot identified in the slot assignment message.