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OPTIMAL ZONE-TO-ZONE ROAMING BY ACCs DURING ZONE-TO-ZONE LINK FAILURE

IP.com Disclosure Number: IPCOM000007793D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2002-Apr-24
Document File: 3 page(s) / 117K

Publishing Venue

Motorola

Related People

Stephanie Wasserberg: AUTHOR

Abstract

In trunked systems, ACC OSWs inform a subscriber unit of sites it should attempt to choose from when it needs to roam. One of the pieces of information in these OSWs is the status ofthe adja- cent site-Site Trunking or Wide Trunking. Subscriber units prefer to be at sites that are in wide trunking because this provides wide-area communication. In a single zone system, a Zone Controller is normally aware of the statuses of all the sites in the system given the site links are operational.

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MOTOROLA Technical Developments

OPTIMAL ZONE-TO-ZONE ROAMING BY ACCs DURING ZONE-TO-ZONE LINK FAILURE

by Stephanie Wasserberg

BACKGROUND

SOLUTION

  In trunked systems, ACC OSWs inform a subscriber unit of sites it should attempt to choose from when it needs to roam. One of the pieces of information in these OSWs is the status ofthe adja- cent site-Site Trunking or Wide Trunking. Subscriber units prefer to be at sites that are in wide trunking because this provides wide-area communication. In a single zone system, a Zone Controller is normally aware of the statuses of all the sites in the system given the site links are operational.

PROBLEM DESCRIPTION

  In OmniLink, a multiple zone system, each Zone Controller is aware of the statuses of all the sites in its zone. However, for OmniLink, sites in different zones can be made adjacent to one another. There- fore, if the link between these two Zone Controllers should go down, the ACC information is no longer guaranteed to be accurate as the site status changes cannot be communicated between Zone Control- lers. As a result, subscriber units could end up bounc- ing between adjacent sites in different zones if the zone-to-zone link should fail while both sites are wide and then each site should go into site trunking. Each Zone Controller cannot communicate to one another that its site has gone into site trunking. See Figure 1 for details.

  A method was developed to allow the radios to roam to sites in another zone while still keeping them from bouncing between sites once the subscriber unit has seen the actual site status of the adjacent site in the other zone. This will be done based on an additional indication in the ACC OSW informing the subscriber units that the zone-to-zone link is down. When a zone-to-zone link fails, the Zone Controller will inform the remotes to change the ACC OSWs to reflect this zone-to-zone link sta- tus. When the subscriber receives ACC OSWs indi- cating that the zone-to-zone link is down, it will recognize this as meaning...