Secure spread spectrum communications using ultrawideband random noise signals
Narayanan,Ram
The Pennsylvania State University
DeMay,Matthew
The Pennsylvania State University
Chuang,Jack
The Pennsylvania State University
Ultrawideband (UWB) random noise signals provide secure communications because they cannot, in general, be detected using conventional receivers and are jam-resistant. We describe the theoretical underpinnings of a novel spread spectrum technique that can be used for covert communications using transmissions over orthogonal polarization channels. The technique is based on the use of heterodyne correlation techniques to inject coherence in a random noise signal. The transmitted signal is featureless and appears unpolarized and noise-like; thus linearly polarized receivers are unable to identify, detect, or otherwise extract useful information from the signal. The system is immune from interference caused by high power linearly polarized signals. Dispersive effects caused by the atmosphere and other factors are significantly reduced since both polarization channels operate over the same frequency band. Our results indicate that the proposed scheme can recover voice and data signals with superior fidelity. Simulations show that we can achieve BER values of 10**-4 at an SNR of around -6 dB without channel coding and BER values sufficient for data and video at much lower SNRs when channel coding is employed, which indicates excellent performance under covert conditions such as operating under the enemy receiver’s thermal noise floor. We also show preliminary field test results with the baseband processing implemented within a software defined radio architecture that clearly validate the system concept.
Jack Chuang received his B.E. degree from National Sun Yet-Sen University, Taiwan, in 2001 and his M.S. degree New Jersey Institute Technology in 2004. Currently, he is working toward his Ph.D. degree in Electrical Engineering at The Pennsylvania State University. His research interests are in the development of noise and noise-like waveforms to achieve reliable LPI/LPD communications.
Matthew DeMay received his B.S. degree with Honors from Syracuse University in 2004 and is currently working toward his M.S. degree in Electrical Engineering at The Pennsylvania State University. His areas of interest include wireless communications system design and implementation and LPI/LPD communications.
Ram Narayanan (corresponding author) is a Professor of Electrical Engineering at the Pennsylvania State University. He received his B.Tech. degree from I.I.T. Madras (India) in 1976 and his Ph.D. degree from UMass (Amherst) in 1988. He is a Fellow of IEEE and Fellow of SPIE. His interests are LPI/LPD radar, image analysis, multisensor fusion, and high resolution imaging.