Strategies for minimizing the intercept time in a mobile communication network with directive/adaptive antennas

For hostile communication environments, a non-centralized mobile communication network with directive/adaptive antennas and Global Positioning System (GPS) has been proposed for the purpose of minimizing the radio exposure and making it difficult for an interceptor to detect the signals. The directive antennas, however, cause a spatial search process to find the direction of the intended receiver and setup a link for communication. During this link setup process, an interceptor has the opportunity to observe the transmitter´s main antenna beam. This paper investigates the strategies for minimizing the intercept time when the interceptor uses a single beam antenna to detect the signal presence and find the transmitter direction. We adopt the Bayes´ rule to recursively update the directional a posteriori probabilities, which leads to a sequential decision problem. Four different algorithms to determine the next search direction based on the updated probabilities are compared through simulations