Anti-Intercept Margins of Relay-Augmented Data Links

A quantitative measure of the anti-intercept improvement (or margin) of a relay data net is described. It is assumed that the link relays are located to obtain the maximum anti-jam advantage against a line-of-sight jammer. The anti-intercept margin is defined as the ratio of the respective spatial power densities available to the intercept receiver when no relay and relays are used, and can be as large as 10-20 dB. It is shown that the relay anti-intercept (AI) margin for a spatially uniform jamming field intensity is lower than for a single jammer environment, and requires the same form of relay spacing needed to maximize the AI margin in the absence of jamming. It is also shown that operation in a lossy medium offers an opportunity for enhancing anti-intercept capability. A measure of overall AI performance that illustrates this enhancement is discussed.