Abstract:
A method of Mission Critical Push to Talk (MCPTT) service performed by a mobile terminal includes: generating, at the mobile terminal, a group call announcement for off-network Mission Critical Push to Talk (MCPTT) service, the group call announcement for off-network MCPTT service including information of a period of the group call announcement for off-network MCPTT service; controlling a transceiver to periodically transmit, to one or more mobile terminals, the group call announcement for off-network MCPTT service based on the period; in response to the transmitted group call announcement for off-network MCPTT service, receiving a response from the one or more mobile terminals; and establishing, based on the response from the one or more mobile terminals, a group call with the one or more mobile terminals by setting a direct wireless communication with the one or more mobile terminals.
Abstract:
Provided is a method for retransmitting received data using index coding and statistical characteristics in a method for transmitting packets, by a transmitter, to at least two receivers in a wireless communication network and retransmitting packets which are not received correctly by each receiver, wherein the transmitter receives a reception acknowledgement response signal for the packets transmitted to the receiver and analyzes received patterns of the reception acknowledgement response signals transmitted from the receiver to differently perform index coding for each received pattern on the packets which are not received correctly by the receiver and retransmit the index-coded packets. According to the exemplary embodiment of the present invention, it is possible to effectively reduce a retransmission frequency of the packets which are not received correctly and a channel use frequency on communications and effectively use limited radio resources.