Software defined radio employing low density spreading for Canadian military applications

无线技术是军事作战场景中不可或缺的一部分。 士兵和基地之间的通信对于加拿大军事人员在敌对环境中履行职责时的安全和成功至关重要。 军事人员使用的无线电设备必须重量轻、移动的，所用波形必须能抗干扰、拦截和探测。 扩频通信最初是由于其抗干扰（AJ），低截获概率（LPI）和低检测概率（LPD）的能力。 然而，使用对映扩频码的直接序列扩频（DS-SS）已经被证明可以简单地通过平方接收信号来检测，允许敌人通过三角测量平方信号来定位发射机，并且也容易受到脉冲干扰。 低密度扩频（LDS）目前是第五代（5G）无线通信系统的候选，其使用扩频码，其中扩频码片由零和不同的复数表示。 零的数量超过非零值，这导致低密度信号。 当该信号被平方时，结果仍然是低密度高带宽信号，其难以检测并且因此难以三角测量。 这种类型的信号对抗脉冲干扰，因为通常当干扰机发射干扰突发时，发射的信号为0。 这意味着在这些情况下，干扰信号将被接收器处的相关器抵消。 * 目前的军用无线电采用慢速跳频扩频（FH-SS）技术，这种技术很容易被跟踪干扰机检测到，然后受到干扰。这些无线电是基于硬件的，已经运行多年。 我们建议实施LDS无线电军事无线通信采用软件定义的无线电平台，这将允许快速采用新兴的无线电技术。 我们将使用Matlab中的Monte Carlo仿真以及使用NordiaSoft的软件定义无线电工具包的仿真来测试LDS解决方案，在许多不同的电子战（EW）场景下，例如干扰和敌对定位。 然后，我们将比较我们的解决方案的性能，现有的军事无线电。 我们还将考虑LDS重负载的通信场景，并考虑多用户检测技术，以确定这些无线电的频谱效率用于商业用途。 ****

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. ****