A method for efficiently processing traffic in an intermediate access point such as a relay station is disclosed. To process traffic directed from one or more terminals to a base station, an intermediate access point supporting two or more communication scheme receives traffic from the one or more terminals according to a first communication scheme, measures a congestion level of the received traffic, transmits a first traffic being part of the received traffic to a second intermediate access point according to a second communication scheme, if the congestion level is equal to or higher than a predetermined threshold, and transmits a second traffic being remaining traffic of the received traffic except the first traffic to the BS.