Performance of non-polarized noise modulated communications system in the presence of interference

The noise modulated non-polarized communication system, developed by us recently, is an ultra-wideband transmitted-reference system designed for secure interference-free communications. By using ultra-wideband random noise to spread the signal and by using polarization diversity for transmitting the spread message and the reference signal, we make the transmitted signal appear totally featureless and noise-like. However, the system may encounter intentional and non-intentional interference since its operating bandwidth is very large. This paper derives analytical models to characterize system performance in partial-band jamming channels and channels containing narrowband interference. Models compare very well with simulations and results validate successful system operation under low signal-to-interference ratio conditions. Research also reveals that the center frequency of transmitted signal must be suitably protected to prevent link outage due to the presence of cross-interference terms. Since multipath acts as self-interference for communication systems, a new method which can improve system performance in multipath environments is also introduced in this paper.