Software defined radio employing low density spreading for Canadian military applications

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Wireless technology is an integral part of military combat scenarios. Communications between soldiers and base are essential to the safety and success of Canadian military personnel while performing their duties in hostile environments. The radio equipment used by military personnel must be lightweight and mobile, and the waveforms used must be resistant to jamming, interception and detection. Spread spectrum communications was originally conceived due to its antijam (AJ), low probability of intercept (LPI) and low probability of detection (LPD) capabilities. However, direct sequence spread spectrum (DS-SS), which uses antipodal spreading codes, has since been shown to be detectable simply by squaring the received signal, allowing the enemy to locate the transmitter by triangulating the squared signal and is also susceptible to pulsed jamming. Low density spreading (LDS), which is currently a candidate for 5th generation (5G) wireless communication systems, uses spreading codes where the spreading chips are represented by zeroes and different complex numbers. The zeroes outnumber the nonzero values, which leads to a low density signal. When this signal is squared, the result is still a low density high bandwidth signal, which is difficult to detect and therefore triangulate. And this type of signal combats pulsed jamming because often when the jammer transmits a jamming burst, the transmitted signal is 0. This means the jamming signal will get cancelled out by the correlator at the receiver during these instances. ****Current military radios employ slow frequency hopped spread spectrum (FH-SS) techniques which are easily detected and then jammed by follower jammers. These radios are hardware-based and have been in operation for many years. We propose to implement LDS radio for military wireless communications employing a software defined radio platform, which will allow for quick adoption of newly emerging radio techniques. We will test the LDS solution, using Monte Carlo simulations in Matlab as well as emulations using NordiaSoft's Software Defined Radio Kits, under a number of different electronic warfare (EW) scenarios, such as jamming and hostile localization. We will then compare the performance of our solution to existing miltiary radios. We will also consider LDS for heavily loaded communication scenarios and consider multiuser detection techniques to determine spectral efficiency of these radios for commercial use. ****