A method of performing relay communication in a next generation cellular communication system is disclosed. The next generation cellular communication system includes a base station and a plurality of terminals, and a communication target terminal which has not acquired a Line-Of-Sight (LOS) channel with the base station performs communication through the relay of a relaying terminal which has acquired a LOS channel. The base station determines the relaying terminal. The relaying terminal forms a relaying terminal group by determining one or more relaying assistant terminals. The communication target terminal forms a transmitting/receiving terminal group by determining one or more transmitting/receiving assistant terminals. The base station performs communication with the relaying terminal through the relaying terminal, relaying assistant terminals of the relaying terminal group and the transmitting/receiving assistant terminals of the transmitting/receiving terminal group.