面向6G通信感知一体化的固定与可移动天线技术

Fixed and Movable Antenna Technology for 6G Integrated Sensing and Communication

多天线技术通过在收发端部署天线阵列,从而提供额外的空间自由度(degrees of freedom,DoFs),大幅提升了无线通信的可靠性与有效性。与此同时,多天线技术应用于雷达感知领域,实现了空间角度分辨能力并提升了感知自由度,大幅增强了无线感知性能。然而,无线通信与雷达感知领域在过去数十年里独立发展。因此,尽管多天线技术在这两个领域分别取得了巨大的进步,但并没有通过发挥它们的协同作用来实现深度融合。随着感知与通信的融合被确定为第六代(the sixth-generation,6G)移动通信网络的典型应用场景之一,多天线技术的发展面临新的机遇以填补上述空白。为此,本文围绕未来天线阵列规模持续扩张、阵列架构更加多样、阵列形态更为灵活等发展趋势,对面向6G通信感知一体化的多天线技术进行综述。首先介绍未来多天线的不同架构类型,包括以传统紧凑式阵列和新兴稀疏阵列为代表的集中式阵列架构、以无蜂窝大规模MIMO(multiple-input multiple-output)为代表的分布式天线架构,以及三维连续空间阵元位置与朝向灵活可调的可移动天线/流体天线。然后,本文将介绍基于上述天线架构的远场/近场信道建模,并进行通信与感知性能分析。最后总结不同天线架构的特点,并展望解决因天线阵列规模的持续扩展及阵列形态的灵活多变引起的信道状态信息获取困难的新思路。

By deploying antenna arrays at the transmitter/receiver to provide additional spatial-domain degrees of freedom(DoFs),multi-antenna technology significantly improves the reliability and efficiency of wireless communication.Meanwhile,the application of multi-antenna technology in the radar field has realized spatial angle resolution and improved sensing DoF.This,in turn,significantly enhances wireless sensing performance.However,wireless communication and radar sensing have undergone independent developments over the past few decades.Hence,although multiantenna technology has dramatically advanced in these two fields separately,it has not been deeply integrated by exploiting their synergy.A new opportunity to bridge this gap arises as the integration of sensing and communication has been identified as one of the typical usage scenarios of the sixth-generation(6G)mobile communication network.Motivated by this,in this study,we aim to explore the multi-antenna technology for 6G integrated sensing and communication(ISAC),with a focus on its future development trends such as continuous expansion of antenna array scale,more diverse array architectures,and more flexible antenna designs.First,we introduce several new and promising antenna architectures,including centralized antenna architectures based on traditional compact arrays or emerging sparse arrays,distributed antenna architectures exemplified by the cell-free massive multiple-input multiple-output(MIMO),and movable/fluid antennas with flexible positions and/or orientations in a given three-dimensional space.Next,for each antenna architecture mentioned above,we present the corresponding far-field/near-field channel models and analyze the communication and sensing performance.Finally,we summarize the characteristics of different antenna architectures and propose new ideas for solving difficulties in acquiring channel state information due to the continuous expansion of antenna array scale and flexible antenna designs.