O-CTP: Hybrid opportunistic collection tree protocol for Wireless Sensor Networks

Radio interference or deliberate jamming attacks can cause highly unpredictable communication in Wireless Sensor Networks (WSNs). Most prevalent WSN platforms consist of low-cost hardware with no effective measures against these threats. Most proposed countermeasures require a more advanced hardware design or radical changes to the 802.15.4 MAC protocol. These alternatives can be very difficult or even impossible to apply to existing WSN designs. In this paper we do not attempt to change the hardware or the MAC protocol. Instead we investigate how WSN routing protocols behave when the network is affected by interference. The paper proposes enhancements of CTP, the de-facto tree-based routing protocol for WSN, using opportunistic routing. We compare our approach with a wide range of protocols: CTP, TYMO, MultihopLQI, broadcast and geographic opportunistic routing in a real-life TelosB testbed subjected to different interference levels. The results show that our hybrid protocol, O-CTP, both improves the data delivery rate and reduces the cost when compared to standard routing protocols.