Effects of Location Awareness on Concurrent Transmissions for Cognitive Ad Hoc Networks Overlaying Infrastructure-Based Systems

Through wideband spectrum sensing, cognitive radio (CR) can identify the opportunity of reusing the frequency spectrum of other wireless systems. To save time and energy of wideband spectrum, we investigate to what extent a CR system incorporating the location awareness capability can establish a scanning-free region where a peer-to-peer ad hoc network can overlay on an infrastructure-based network. Based on the carrier sense multiple access with collision avoidance (CSMA/CA) medium access control (MAC) protocol, the concurrent transmission probability of a peer-to-peer connection and an infrastructure-based connection is computed. It is shown that the frequency band of the legacy system can be reused up to 45 percent by the overlaying cognitive ad hoc network when CR users have the location information of the primary and secondary users.