Browse Prior Art Database

All Start Methods

IP.com Disclosure Number: IPCOM000180411D
Original Publication Date: 2009-Mar-09
Included in the Prior Art Database: 2009-Mar-09
Document File: 6 page(s) / 335K

Publishing Venue

Motorola

Related People

Aparna Pandey: INVENTOR [+2]

Abstract

Methods for keeping track of group member presence information as well as those for communicating this information to the originator are disclosed. The solution can be divided into two parts: - Keeping track of the number of group members in the call at the Gateway. - Announcing group member information to the originator of a group call.

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All Start Methods

By Aparna Pandey, Bob LoGalbo

 

ABSTRACT

Methods for keeping track of group member presence information as well as those for communicating this information to the originator are disclosed. The solution can be divided into two parts:

- Keeping track of the number of group members in the call at the Gateway.

- Announcing group member information to the originator of a group call. 

PROBLEM

All start is a “must have” feature for many of our public safety customers.  The goal of all start is to maximize the probability that all members of a talkgroup hear the call regardless of location. This feature is not implemented either in current broadband networks such as WiMAX, LTE, EVDO etc. or in heterogeneous networks with Public Safety narrowband and public/private broadband sub-systems. Thus, there exists a need to provide such a feature for these technologies. 

The architectural purpose of all start in our trunked systems today:  before granting a “Permit” tone to the originator of an all start call, ensure that an RF resource (i.e. a voice channel) is available at every site where there is at least one mandatory target talkgroup receiver of the all start call; otherwise busy queue the call with no Permit granted to the originator.  From an infrastructure perspective, the goal is to virtually eliminate the possibility that any mandatory receivers of the call will miss it.  Of course there are no guarantees if target receivers are in poor coverage or are scanning some other site.  However, from a system perspective, the architecture shall not contribute in any significant way (i.e. race conditions) to the mandatory receivers missing the all start call.

Today the Zone Controller is aware of how many RF resources are available at all of the sites all of the time.  In addition, the ZC knows where all of the members of the talkgroup are.  With this knowledge, the ZC can ensure before granting the “Permit” to the originator, that a resource is available at all sites which have at least one member of the designated talkgroup of the all start call.   When the ZC grants a “Permit” for an all start call to the originator, it doesn’t wait until all mandatory receivers of the call have moved to a voice channel; rather the ZC notifies each site controller concurrently to send a voice channel assignment over the control channel at the same time.  This notification occurs at the same time it sends the “Permit” to the all start call originator.  The system is designed to send all members of the group to the voice channel with minimal signaling bounces -no feedback from the subscribers are necessary.  The site controller sends over the control channel the group/voice channel assignment without dependence on subscriber acknowledgment.  This reduces race condition risk, complexity, ...