Jamming effects on frequency-hopping ad hoc networks - Performance analysis

Protection against jamming is essential for tactical radio networks. Frequency hopping (FH) is an often used jamming protection technique. An adaptive jammer, such as a fast follower jammer can be a serious threat to a tactical ad hoc network using FH. Another non-adaptive FH jamming threat is partial-band noise jamming. In this report, ad hoc networks exposed to jamming are examined. Firstly, an approximative analytical method and performance criteria are devised. Using these criteria for follower and partial-band jamming we examine the effect of parameters like distance to jammer, communication distance between nodes, frequency hopping rate, jamming power, response time of jammer and error correcting capability of the radio system. Secondly, to study network properties under follower jamming, network simulations are performed. Focus is to examine how the terrain and the network protocols influence the jamming resistance. The terrain influences how easy it is to jam a network. For the cases investigated, a network in a flat terrain becomes more jammed than the corresponding network in a hilly terrain. The packet delivery ratio is measured when the network protocol OLSR MPR-flooding is used and compared to a network using full flooding. Even if not as robust as full flooding, OLSR MPR-flooding is still relatively robust. We also show that it is enough to jam the control slots used by the network protocols to have an impact on the network delivery ratio.