In this paper, we propose the location-aware routing protocol (LRP) to enhance the spectrum efficiency in mobile overlay cognitive ad hoc network and provide the adaptive transmission angle management to reduce the number of control packet. The main contributions of this paper can be summarised as follows. First, we propose a LRP to improve the spectrum efficiency for the considered networks. The LRP can establish a route by avoiding the coverage of primary users (PUs). Second, the LRP selects the next node that is the nearest node from the centre line between a source node and a destination node. Thus, the proposed routing protocol can transmit the data packet stably. Third, we propose an adaptive transmission angle management that takes into account the previous session route state in order to reduce the amount of control packet in the considered networks.