Spatial filtering based on multiple-input multiple-output (MIMO) processing is a promising approach to jammer mitigation. Effective MIMO data detectors that mitigate smart jammers have recently been proposed, but they all assume perfect time synchronization between transmitter(s) and receiver. However, to the best of our knowledge, there are no methods for resilient time synchronization in the presence of smart jammers. To remedy this situation, we propose JASS, the first method that enables reliable time synchronization for the single-user MIMO uplink while mitigating smart jamming attacks. JASS detects a randomized synchronization sequence based on a novel optimization problem that fits a spatial filter to the time-windowed receive signal in order to mitigate the jammer. We underscore the efficacy of the proposed optimization problem by proving that it ensures successful time synchronization under certain intuitive conditions. We then derive an efficient algorithm for approximately solving our optimization problem. Finally, we use simulations to demonstrate the effectiveness of JASS against a wide range of different jammer types.

翻译：基于多输入多输出（MIMO）处理的空间滤波是抑制干扰的有效方法。尽管近期已有针对智能干扰的MIMO数据检测方案被提出，但这些方法均假设发射机与接收机之间具有完美的时间同步。然而，据我们所知，目前尚无在智能干扰下实现鲁棒时间同步的方法。为解决这一问题，我们提出JASS——首个能够在单用户MIMO上行链路中抑制智能干扰攻击的同时实现可靠时间同步的方法。JASS通过设计一种新的优化问题来检测随机化同步序列：该优化问题将空间滤波器拟合到时域加窗接收信号中，从而抑制干扰。我们通过证明该优化问题在特定直观条件下能保证成功时间同步，凸显其有效性。随后我们推导出近似求解该优化问题的高效算法。最后，通过仿真验证了JASS对多种不同类型干扰的有效性。