Patent ID: 9370023
Filing Date: 2016-06-14
CPC Classification: H04W

Claim Text:
1. A method for resolving call collisions in a direct mode communication system among a plurality of direct mode radios, the method comprising, at an initiating direct mode radio: monitoring a direct mode communication channel for transmissions from other direct mode radios in the plurality of direct mode radios, wherein the direct mode communication system has no base station or repeater infrastructure, and wherein direct mode is a mode of operation where radios communicate directly with each other over a single shared RF frequency without the use of any infrastructure equipment; responsive to detecting a request to initiate a new direct mode call on the direct mode communication channel: identifying, via the monitoring, a last one of the other direct mode radios to transmit on the direct mode communication channel; transmitting a new call request for receipt by the last one of the other direct mode radios to transmit on the direct mode communication channel; monitoring the direct mode communication channel for a response from the last one of the other direct mode radios to transmit on the direct mode communication channel; if a call grant is received from the last one of the other direct mode radios to transmit on the direct mode communication channel granting the new call request, initiating the new direct mode call on the direct mode communication channel; and if the call grant is not received from the last one of the other direct mode radios to transmit on the direct mode communication channel granting the new call request, at least temporarily refraining from initiating the new direct mode call on the direct mode communication channel, thereby resolving potential call collisions.