Optimal placement of protective jammers for securing wireless transmissions in a geographic domain

Wireless communication systems, such as RFIDs and wireless sensor networks, are increasingly being used in security-sensitive applications, e.g. credit card transactions or monitoring patient health in hospitals. Wireless jamming by transmitting artificial noise, which is traditionally used as an offensive technique for disrupting communication, has recently been explored as a means of protecting sensitive communication from eavesdroppers. In this paper, we consider location optimization problems related to the placement and power consumption of such friendly jammers in order to protect the privacy of wireless communications constrained within a geographic region. Under our model, we show that the problem of placing a minimum number of fixed-power jammers is NP-Hard, and we provide a PTAS ((1 + ε)-approximation scheme) for the same, where ε is a tunable parameter between 0 and 1.