A system with WLAN link aggregation comprises an access point, a station and a remote host. The station is equipped with a first network interface unit and a second network interface unit. The first network interface unit and the second network interface unit are configured to forward packets to or receive packets from the access point. After receiving packets from the first network interface unit, the second network interface unit or the remote host, the access point modifies headers of the packets and forwards the packets to the first network interface unit, the second network interface unit or the remote host.