Efficient cooperative channel sensing in cognitive radio ad hoc networks

It is expected for multi-channel ad hoc networks to adopt cognitive radio (CR) technology since the CR technology can provide enough channels for high speed data transmission. These CR ad hoc networks should maintain accurate channel state information not only for protecting primary users (PUs) but also for obtaining enough channels. To cope with this, we propose a novel dissemination scheme for channel state information and an adjustment scheme of sensing priorities. According to the proposed dissemination scheme, a CR node can inform the PU presence or a request for a temporary quiet period on a channel for its sensing. When a CR node receives the PU presence on a channel, the CR node adjusts the sensing priority of a channel in order to confirm the availability of the channel by its own sensing. With these schemes, CR nodes cooperate together to accurately maintain the channel state information while each CR node grasps available channels in its own location. Using a simulation, we show that the proposed scheme provides more channels while guaranteeing the right of PUs. Since the proposed scheme uses only two bit channel map for informing the channel status and sends it on top of control packets, the performance gain can be achieved by low overhead.