In this paper, we propose an efficient structure of base station (BS) scheduler for the wireless broadband (WiBro) system. The BS scheduler consists of an uplink scheduling block, a downlink scheduling block and a channel quality information block. Both uplink and downlink scheduling blocks operate closely with a channel quality information block to schedule downlink packets and allocate uplink/downlink radio resources. Next, we propose a new efficient scheduling algorithm for WiBro systems. The proposed algorithm utilizes the user-based scheduling to relieve the MAP overhead problem and to modify the normal proportional fair (PF) scheduling algorithm to guarantee user-based quality of service (QoS). The simulation study shows that the proposed algorithm relieves the MAP overhead problem by allocating the minimum number of user bursts in a frame and supports better fairness performance, while supporting the system throughput performance similar to that of the normal PF scheduling algorithm