Browse Prior Art Database

Dynamic Timer Control For Trunked Subscriber Radios

IP.com Disclosure Number: IPCOM000008225D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2002-May-29
Document File: 1 page(s) / 85K

Publishing Venue

Motorola

Related People

Les Gustafson: AUTHOR [+2]

Abstract

In current trunked radio systems, subscriber units can be issued a busy status in response to a service request if there are not enough resources available to support their call. The subscriber can then notify the user that the request has been queued and a grant will be issued when sufftcient resources become available. The subscriber unit will continue to receive confirmation that the busy state still exists via periodic control channel updates. If an busy update is not received within a pre-defined time-out period, the subscriber unit will assume that its call has been missed or canceled and continue with normal operation.

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Dynamic Timer Control For Trunked Subscriber Radios

by Les Gustafson and Dan Jenkins

SYSTEM BACKGROUND

  In current trunked radio systems, subscriber units can be issued a busy status in response to a service request if there are not enough resources available to support their call. The subscriber can then notify the user that the request has been queued and a grant will be issued when sufftcient resources become available. The subscriber unit will continue to receive confirmation that the busy state still exists via periodic control channel updates. If an busy update is not received within a pre-defined time-out period, the subscriber unit will assume that its call has been missed or canceled and continue with normal operation.

  The tnmking fixed end equipment issues busy updates on the control channel along with all other system activity that must be supported. This creates a situation where the repeat interval of a given busy update message is dependent on system loading and activity. Busy updates will be more frequent on lightly loaded systems than on heavily loaded systems. Given this fact the update rate expected by the sub- scriber unit must be large enough to accommodate the heaviest system loading cases possible. The drawback to this is that a subscriber unit must be designed to expect slow busy update rates at the expense of responsiveness to canceled or missed calls. It is much more desirable to have a subscriber radio that can detect a canceled busy state immediately rather than some time after the actual event has occurred.

  Faced with the described situation, current sub- scriber radios opt for a busy update repeat rate timer value that is typically in the range of 4 - 10 seconds. With this value the user experiences reasonable response times to missed or canceled calls and the radio will not errantly time out a busy condition in all cases except the largest peaks in system loading. Unfortunately, this is only a tradeoff between...