This paper studies the problem of sum-secure degrees of freedom (SDoF) of the (M,M,N,N) multiple-input multiple-output (MIMO) interference channel with local output feedback, so as to build an information-theoretic foundation and provide practical transmission schemes for 6G-enabled vehicles-to-vehicles (V2V). For this problem, we propose two novel transmission schemes, i.e., the interference decoding scheme and the interference alignment scheme, and thus establish a sum-SDoF lower bound. In particular, to optimize the phase duration, we analyze the security and decoding constraints and formulate a linear-fractional optimization problem. Furthermore, we show that the derived sum-SDoF lower bound is the sum-SDoF for M <= N/2, N=M, and 2N <= M antenna configurations, and reveal that for a fixed N, the optimal M to maximize the sum-SDoF is not less than 2N. Through simulations, we examine the secure sum-rate performance of proposed transmission schemes, and reveal that using local output feedback can lead to a higher secure sum-rate than that by using delayed channel state information at the transmitter.

翻译：本文研究了(M,M,N,N,N)多投入多输出干扰渠道对当地产出反馈的多输出干扰(MIMO)总安全度问题,以便建立一个信息理论基础,为6G驱动的车辆对车辆(V2V)提供实用的传输计划。关于这一问题,我们提出两个新型传输计划,即干扰解码计划和干扰校正计划,从而建立一个小于2N的SDoF。特别是为了优化阶段持续时间,我们分析安全和解码限制,并制定线性优化问题。此外,我们表明,衍生的SDOF下限是M ⁇ N/2 N=M和2N ⁇ M天线配置的SDoF,并表明,对于固定的N而言,最大限度增加SDoF的最佳M不少于2N。我们通过模拟,检查拟议的传输计划的安全总和率绩效,并表明使用当地产出反馈可导致使用比国家延迟的导航系统更安全的总和率。