Portable unlicensed devices operating in TV white space must adhere to FCC rules designed to protect licensed devices. These rules decrease the achievable throughput for the portable unlicensed devices because the portable unlicensed devices are required to perform a channel availability query (CAQ) before transmitting. In order to reduce the number of CAQs, the Federal Communications Commission allows a regionbased mobility procedure (RMP). In this paper, we propose a new-RMP using directional information in order to enhance the achievable throughput. Directional information enables an unlicensed portable device to increase its achievable throughput by considering a uni-directional region that is smaller than an omni-directional region. Simulation results show that the proposed RMPs enhance the achievable throughput compared to the conventional RMPs. In addition, the achievable throughput for the proposed RMP using a navigation system is greatly enhanced compared to the conventional RMPs.