Secure Communications with Superimposed Pilots

In this paper, we propose a system concept enabling secure communications by introducing superimposed pilots. The superimposed pilots can be exploited in a trellis-based joint channel tracker and data detector by the user of interest. Further, the user of interest can adjust the power ratio between the user data and superimposed pilot, which yields the secure capacity region. It allows the user of interest to appropriately select the Forward Error Correction (FEC) code rate, so that the eavesdropper will not be able to decode the corresponding data any more. In this paper, we present the achievable secure capacity region for not only Single-Input Single-Output (SISO) system, but also Multiple-Input Single-Output (MISO) with Space-Time Coding (STC), and Multiple-Input Multiple-Output (MIMO) with Spatial Multiplexing (SMX) via Monte Carlo simulation.