Effect of Jamming Signals on Wireless Ad Hoc and Sensor Networks

In Ad Hoc or sensor networks, communication may be achieved between mobile nodes without a central entity (base station), in a half-duplex manner. The impact of jamming signals on those kinds of networks is studied. The contributions of this paper can be divided into two parts. In the first part, the probability of success, throughput and the maximum throughput are derived for the half-duplex Slotted ALOHA in terms of the node transmitting probability, the node receiving probability and average jamming signals rate. Results show that the probability of success, throughput and maximum throughput decrease with the increase of average jamming signals rate. In the second part, the effect of jamming signals on the maximum throughput of retransmission cut-off half-duplex Slotted ALOHA is studied. A close form equation is obtained for the transmission probability from each mobile node that maximizes the channel throughput in the presence of jamming signals. This equation provides the relationship between the new packet transmission probability from each mobile node, jamming signals rate and the number of retransmission attempts. The number of retransmission attempts plays an important role for a lower value of jamming signals rate. The results of this study may be used for system design of half-duplex contention-based multiple access schemes with and without jamming signals and retransmission cut-off.