Integrated sensing and communication (ISAC) capability is envisioned as one key feature for future cellular networks. Classical half-duplex (HD) radar sensing is conducted in a "first-emit-then-listen" manner. One challenge to realize HD ISAC lies in the discrepancy of the two systems' time scheduling for transmitting and receiving. This difficulty can be overcome by full-duplex (FD) transceivers. Besides, ISAC generally has to comprise its communication rate due to realizing sensing functionality. This loss can be compensated by the emerging reconfigurable intelligent surface (RIS) technology. This paper considers the joint design of beamforming, power allocation and signal processing in a FD uplink communication system aided by RIS, which is a highly nonconvex problem. To resolve this challenge, via leveraging the cutting-the-edge majorization-minimization (MM) and penalty-dual-decomposition (PDD) methods, we develop an iterative solution that optimizes all variables via using convex optimization techniques. Besides, by wisely exploiting alternative direction method of multipliers (ADMM) and optimality analysis, we further develop a low complexity solution that updates all variables analytically and runs highly efficiently. Numerical results are provided to verify the effectiveness and efficiency of our proposed algorithms and demonstrate the significant performance boosting by employing RIS in the FD ISAC system.

翻译：集成感知与通信（ISAC）能力被视为未来蜂窝网络的关键特征之一。传统的半双工（HD）雷达感知采用"先发射后接收"模式，实现HD ISAC的挑战之一在于两个系统收发时间调度的不一致性。而全双工（FD）收发器可克服这一困难。此外，ISAC通常需因实现感知功能而折损通信速率，这一损失可通过新兴的可重构智能表面（RIS）技术得到补偿。本文研究RIS辅助的FD上行通信系统中波束成形、功率分配与信号处理联合设计这一高度非凸问题。为应对此挑战，我们利用前沿的MM（majorization-minimization）与PDD（penalty-dual-decomposition）方法，开发出一种通过凸优化技术优化所有变量的迭代求解方案。此外，通过巧妙运用ADMM（alternative direction method of multipliers）及最优性分析，我们进一步提出一种低复杂度求解方案，该方案可解析更新所有变量且运行高效。数值结果验证了所提算法的有效性与效率，并展示了在FD ISAC系统中部署RIS带来的显著性能提升。