A CSMA with threat avoidance protocol for ad-hoc wireless network

Ad hoc network is a wireless mobile network that does not have any base station or other central control infrastructures. Routes in this type of network usually contain multiple hops. IEEE802.11 DCF is the mostly used MAC protocol in a lot of simulations and test beds. However, the hidden node problem cannot be avoided upon the occurrence of threat nodes in conventional 802.11 DCF and it could adversely impact upper layer performance such as low throughput, TCP instability, etc. In this paper, we present an extension to 802.11 DCF MAC protocol to solve this issue. We propose a new scheme that uses separate control channel and data channel as well as adaptive power level CTS to reach nodes in threat zone. With adaptive power CTS notification, nodes in threat zone can back off for some interval when they have an intention to send data frames and hence can avoid the collisions usually caused by threat nodes in 802.11.