Drawing inspiration from the advantages of intelligent reflecting surfaces (IRS) in wireless networks,this paper presents a novel design for intelligent omni surface (IOS) enabled integrated sensing and communications (ISAC). By harnessing the power of multi antennas and a multitude of elements, the dual-function base station (BS) and IOS collaborate to realize joint active and passive beamforming, enabling seamless 360-degree ISAC coverage. The objective is to maximize the minimum signal-tointerference-plus-noise ratio (SINR) of multi-target sensing, while ensuring the multi-user multi-stream communications. To achieve this, a comprehensive optimization approach is employed, encompassing the design of radar receive vector, transmit beamforming matrix, and IOS transmissive and reflective coefficients. Due to the non-convex nature of the formulated problem, an auxiliary variable is introduced to transform it into a more tractable form. Consequently, the problem is decomposed into three subproblems based on the block coordinate descent algorithm. Semidefinite relaxation and successive convex approximation methods are leveraged to convert the sub-problem into a convex problem, while the iterative rank minimization algorithm and penalty function method ensure the equivalence. Furthermore,the scenario is extended to mode switching and time switching protocols. Simulation results validate the convergence and superior performance of the proposed algorithm compared to other benchmark algorithms.

翻译：受智能反射面(IRS)在无线网络中优势的启发，本文提出了一种新型智能全向面(IOS)赋能的集成感知与通信(ISAC)设计方案。通过利用多天线和大量单元的能力，双功能基站(BS)与IOS协同实现联合主动与被动波束赋形，从而支持无缝的360度ISAC覆盖。目标是在确保多用户多流通信的同时，最大化多目标感知的最小信干噪比(SINR)。为实现这一目标，采用了一种全面的优化方法，涵盖雷达接收向量、发射波束赋形矩阵以及IOS透射和反射系数的设计。由于所构建问题的非凸性质，引入辅助变量将其转化为更易处理的形式。基于块坐标下降算法，将问题分解为三个子问题。利用半定松弛和逐次凸近似方法将子问题转化为凸问题，同时通过迭代秩最小化算法和罚函数方法确保等价性。此外，场景扩展至模式切换和时间切换协议。仿真结果验证了所提算法相比其他基准算法的收敛性和优越性能。