Patent ID: 7529223
Filing Date: 2009-05-05
Classification: H04W,Y02D

Abstract:
1. A method of synchronizing mobile terminals on a direct mode radio channel, wherein each communication occupying the channel comprises the transmission directly between mobile terminals of signals distributed into traffic time slots and into regularly dispersed control time slots on said direct mode channel during which one of the mobile terminals transmits synchronization and signaling signals, the method comprising the steps of determining, based on synchronization and signaling signals transmitted directly between said mobile terminals, by at least some of the terminals standby time slots coincided with the control slots on said direct mode channel and wherein the standby time slots continue to be coincided with the control slots after the communication, and placing said at least some of the terminals in a receive state on the channel during the coincided standby slots, with idle periods between said standby slots, the method further comprising the following steps in response to detection on the channel of signals other than synchronization and signaling signals in a standby slot by a mobile terminal keeping said mobile terminal in the receive state on the channel; determining new standby time slots by said mobile terminal if synchronization and signaling signals are detected; and determining by some at least of the terminals standby time slots desynchronized with respect to the control slots, having a different periodicity from that of the control slots and wherein the standby time slots continue to be coincided with the control slots after the communication, and placing some at least of the terminals in the receive state on the channel during the desynchronized standby slots.