Patent ID: 8457104
Filing Date: 2013-06-04
Classification: H04J,H04W

Abstract:
1. A method for synchronizing direct mode time division multiple access (TDMA) transmissions among a plurality of direct mode radios, the method comprising: receiving, by a first radio, a communication from a second radio defining time slot boundaries being used by the second radio, the communication including first timing synchronization information identifying (i) a first timing synchronization leader radio to which the second radio is currently time slot boundary synchronized and (ii) an indication of how much time has passed since a direct synchronization with the first timing synchronization leader radio established the time slot boundaries being used by the second radio; identifying, by the first radio, an updated timing leader according to a timing leadership election rule that compares a first timing leader parameter associated with the identified first timing synchronization leader radio identified in the communication and one of (i) a second timing leader parameter associated with the first radio when the first radio is not already time slot synchronized with a leader radio and (ii) a third timing leader parameter associated with a second timing synchronization leader radio to which the first radio is currently time slot boundary synchronized; setting, by the first radio, the updated timing leader as its timing leader; and synchronizing, by the first radio, a time slot boundary with a time slot boundary defined by the updated timing leader.