Method for transmitting/receiving data in wireless communication system and device for supporting same

A method for receiving, by a receiving device, data in a wireless communication system, the method comprising:

• receiving, from a transmitting device, specific data and at least one duplicate data on a plurality of cells associated with a plurality of radio bearers;
• delivering the specific data and the at least one duplicate data from a first layer of the receiving device to a second layer of the receiving device;
• and
• storing the specific data and the at least one duplicate data in a reception buffer of the second layer,
• wherein the specific data and the at least one duplicate data are de-multiplexed by the first layer,
• wherein the at least one duplicate data is data generated using the specific data, and
• wherein the reception buffer discards remaining data excluding one data from multiple same data.

A transmitting device for transmitting data to a receiving device in a wireless communication system, the transmitting device comprising:

• a communication unit configured to transmit and receive a radio signal with an outside;
• and
• a processor functionally coupled to the communication unit,
• wherein the processor is configured to:
• reconfigure specific data in a second layer of the transmitting device based on a resource allocation amount delivered from a first layer of the transmitting device;
• generate at least one duplicate data according to a number of a plurality of radio bearers using the reconfigured specific data;
• and
• transmit the reconfigured specific data and the at least one duplicate data to the receiving device on a plurality of cells associated with the plurality of radio bearers,
• wherein in the plurality of radio bearers, a transmission of duplicate data is indicated by a bearer identifier, and
• wherein partial data of the at least one duplicate data are transmitted to a second layer of a second transmitting device in which the transmission of the duplicate data is indicated by the bearer identifier.