The scope of this document addresses the procedures and associated messaging for the following types of Dynamic Regrouping:

• Two-way regroup (a.k.a. Patch) (MFIDA4 and MFID90)

• One-way regroup (a.k.a. Simulselect) (MFIDA4 only)

• Individual regroup (MFID90 only)

The procedures and associated messaging specified in this document support Dynamic Regrouping over the FDMA (U_m) and Two-Slot TDMA (U_m2) Common Air Interfaces.

Purpose

The purpose of this document is to specify the messaging and procedures that allow Dynamic Regrouping operations in a trunking system. The term "Dynamic Regrouping" refers to Individual and Group Regrouping operations.

Individual regrouping assigns an affiliated radio to a new talkgroup for communication purposes. This allows radios to be reassigned over the air without the need for intervention by the radio user. Group Regrouping is done by signaling regrouping information to SUs currently affiliated to the affected talkgroups. The talkgroups are grouped together into a larger talkgroup called a ‘supergroup.' A supergroup is a unique type of working group only used in Group Regrouping operations. The acronym for a ‘Supergroup Working Group ID' is ‘SP-WGID.'

Group regrouping may take the form of a two-way regroup (a.k.a. "patch) or a one-way regroup (a.k.a. "simulselect). Both patch and simulselect allow communication with multiple groups on a single voice channel by linking multiple groups into a supergroup. A two-way patch allows voice communications in both directions on the Supergroup Working Group ID (SP-WGID), from dispatcher to SUs and from SUs to SUs and dispatchers. A ‘simulselect' is a one-way patch, from dispatcher to SUs only, where SUs are only allowed to receive on the SP-WGID while transmitting on their normally selected WGID.

Currently deployed implementations support one of two different methods, referred to as "MFIDA4 Explicit Encryption" or "MFID90 Airlink Efficient." Since both of these methods are already available in the field, the TIA/TR8 Private Land Mobile Radio committee decided to accept both of these methods into the TIA-102 suite of Standards. This document describes the specifications of these methods. An RFSS may implement the MFIDA4 method, or the MFID90 method, or both. Subscriber manufacturers shall implement both methods to ensure interoperability across different RFSSs.