Method and device for synchronising mobile terminals on a radio channel in direct mode
AssigneeEADS Defence and Security Networks
InventorsGerard Marque Pucheu, Guillaume Pascal, Francois Piroard
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Abstract
The invention concerns a method whereby each of the communication using the channel comprises transmission between mobile terminals (11-13) of signals distributed into traffic time intervals and uniformly distributed control time intervals during which one of the mobile terminals transmits synchronising and signalling signals. Some at least of the terminals determine standby time intervals aligned on the control intervals and maintained after communication, and are set in reception on the channel during the standby time intervals, with idle periods between said standby time intervals.
Claims18
A method of synchronizing mobile terminals (11-13) on a direct mode radio channel, wherein each communication occupying the channel comprises the transmission between mobile terminals of signals distributed into traffic time slots and into regularly dispersed control time slots during which one of the mobile terminals transmits synchronization and signaling signals, characterized in that some at least of the terminals determine standby time slots aligned with the control slots and continuing after the communication, and place themselves in a receive state on the channel during the aligned standby slots, with idle periods between said standby slots.
The method as claimed in any one of the preceding claims, wherein, in response to the detection on the channel of signals other than synchronization and signaling signals in a standby slot, a mobile terminal (11-13) remains in the receive state on the channel and determines new standby time slots if it detects synchronization and signaling signals.
The method as claimed in any one of the preceding claims, wherein, to initiate a new communication, a mobile terminal (11-13) transmits synchronization and signaling signals until the next aligned standby slot.
A control device for a mobile radiocommunication terminal, the terminal comprising means of transmission (22) and of reception (23) on a direct mode radio channel, whereby each communication occupying said channel comprises the transmission between mobile terminals (11-13) of signals distributed into traffic time slots and into regularly dispersed control time slots during which one of said mobile terminals transmits synchronization and signaling signals, the control device comprising means of activation of the means of reception on the channel during standby slots and of deactivation of the means of reception on the channel outside the standby slots, characterized in that it comprises means for determining time slots, continuing after the communication, which are aligned with control slots positioned in the course of a communication by detection of synchronization signals transmitted by another terminal and for including said aligned slots in the standby slots.
A mobile radiocommunication terminal, comprising means of transmission (22) and of reception (23) on a direct mode radio channel and a control device, whereby each communication occupying said channel comprises the transmission between mobile terminals (11-13) of signals distributed into traffic time slots and into regularly dispersed control time slots during which one of said mobile terminals transmits synchronization and signaling signals, the control device comprising means of activation of the means of reception on the channel during standby slots and of deactivation of the means of reception on the channel outside the standby slots, characterized in that it comprises means for determining time slots, continuing after the communication, which are aligned with control slots positioned in the course of a communication by detection of synchronization signals transmitted by another terminal and for including said aligned slots in the standby slots.
Dependencies are inferred from the claim text.