Distributed method of call arbitration in an rf trunking multisite

Abstract

A method for resolving talk group call contention in a multi-site trunked radio frequency communications network is accomplished in a distributed manner by utilizing autonomous call arbitration processes at each interface node to avoid potential performance bottlenecking and a 'single point of failure' configuration that would arise in a conventional centralized arbitration arrangement. Call contention in a multi-site environment occurs when multiple callers at different sites attempt to transmit on a common talk group at nearly the same moment. The call processing system that coordinates communications between sites must resolve this contention to ensure that the transmission is processed consistently at all sites. In accordance with the distributed manner of the present invention, each site interface autonomously determines which call should be given priority in a contention situation based upon a predetermined common set of arbitration 'rules'. The arbitration scheme can most succinctly be described as 'first call wins, tie goes to the highest numbered site.' Calls that lose contention are subsequently processed as 'console-only' calls. In addition, the distributed arbitration method of the present invention also provides for the handling of 'emergency' calls by giving those calls priority over non-emergency calls.