Method for receiving multicast data in M2M device included in wireless communication system and M2M device therefor
Disclosed are a method for receiving multicast data in a machine to machine (M2M) device in a wireless communication system and an M2M device therefor. The M2M device receiving multicast data according to the present invention, includes a receiver receiving multicast control information for transmitting multicast data from a base station, and the multicast control information includes a retransmission indicator field which indicates whether corresponding multicast data is retransmitted or not.
1. A method for receiving multicast data at a Machine-to-Machine (M2M) device in a wireless communication system, the method comprising:
receiving multicast data from a base station in an idle mode;
transmitting a ranging request message, upon failing to decode the multicast data,
wherein the ranging request message includes a ranging purpose indication (RPI) and a multicast group identifier (ID) associated with the M2M device; and
re-receiving the multicast data from the base station through a ranging response message in response to the ranging request message based on the multicast group ID, if the RPI indicates a multicast data retransmission request from the M2M device.
2. The method according to claim 1 , further comprising:
receiving uplink resource assignment information for transmitting an acknowledgement (ACK) signal for the multicast data in response to the ranging request message from the base station, together with the multicast data.
3. The method according to claim 2 , further comprising:
transmitting a positive ACK signal to the base station based on the uplink resource allocation information, upon succeeding in decoding the re-received multicast data from the base station.
4. The method according to claim 2 , wherein the uplink resource allocation information is transmitted as a unicast control information type.
5. The method according to claim 2 ,
wherein failing to decode the multicast data is caused by one of a decoding error of a downlink multicast data burst, missing a medium access control (MAC) protocol data unit (MPDU) sequence number corresponding to the multicast data confirmed by checking the MPDU sequence number, expiration of a timer which is reset whenever the multicast data is received, and non-reception of control information for the multicast data at an indicated multicast data transmission start time.
6. The method according to claim 1 , further comprising:
transmitting a positive acknowledgement (ACK) signal, upon succeeding in decoding the multicast data received through the ranging response message.
7. A Machine-to-Machine (M2M) device for receiving multicast data in a wireless communication system, the M2M device comprising:
a radio frequency (RF) unit configured to receive and transmit data; and
a processor configured to process the data received and transmitted by the RF unit,
wherein the processor is further configured to:
receive multicast data from a base station in an idle mode,
transmit a ranging request message, upon failing to decode the multicast data,
wherein the ranging request message includes a ranging purpose indication (RPI) and a multicast group identifier (ID) associated with the M2M device, and
re-receive the multicast data from the base station through a ranging response message in response to the ranging request message based on the multicast group ID, if the RPI indicates a multicast data retransmission request from the M2M device.
8. The M2M device according to claim 7 ,
wherein the processor failing to decode the multicast data is caused by one of a decoding error of a downlink multicast data burst, missing a medium access control (MAC) protocol data unit (MPDU) sequence number corresponding to the multicast data confirmed by checking the MPDU sequence number, expiration of a timer which is reset whenever the multicast data is received, and non-reception of control information for the multicast data at an indicated multicast data transmission start time.