With potential applications to short-packet communication, we address communication of low-latency messages in fast-fading channels under the presence of a reactive jammer. Unlike a traditional jammer, we assume a full-duplex (FD) jammer capable of detecting pre-existing countermeasures and subsequently changing the target frequency band. To facilitate reliable communication amidst a strong adversary, we propose non-coherent fast-forward full-duplex relaying scheme wherein the victim uses a helper in its vicinity to fast-forward its messages to the base station, in addition to ensuring that the countermeasures are undetected by the FD adversary. Towards designing the constellations for the proposed scheme, we identify that existing non-coherent constellation for fast-fading channels are not applicable owing to the cooperative nature of the fast-forward scheme. As a result, we formulate an optimization problem of designing the non-coherent constellations at the victim and the helper such that the symbol-error-probability at the base station is minimized. We theoretically analyze the optimization problem and propose several strategies to compute near-optimal constellations based on the helper's data-rate and fast-forwarding abilities. We show that the proposed constellations provide near-optimal error performance and help the victim evade jamming. Finally, we also prove the scheme's efficacy in deceiving the countermeasure detectors at the jammer.
翻译:与传统的干扰器不同,我们假设一个完全不协调的干扰器,能够探测到原有的反措施,并随后改变目标频带。为了在强大的对手之间促进可靠的通信,我们提出一个不连贯的快速向前完全不协调的转发系统,让受害人在其附近使用一个助手将其信息快速传送到基地站,此外还确保FD对手无法发现对策。在为拟议办法设计星座时,我们假定一个能够探测到原有反措施并随后改变目标频带的全不协调的干扰器。我们发现,由于快速向上办法的合作性质,现有的不协调的快速向前移动全不协调的干扰器并不适用。结果,我们提出了一个设计受害者不连贯的快速向前向前移动的全不统一转发系统的最佳问题,使基地站的标志-eror-可探测性最小化。我们从理论上分析了最优化的问题,并提出了若干战略,用以对近为快速向外移动的通道设置的不协调的星座进行对比。我们提出在快速向上展示快速向受害者展示的螺旋图,我们展示了快速向上的最后的螺旋图。