6G-REFERENCE: 6G haRdware Enablers For cEll fRee cohEreNt Communications & sEnsing

在城市地区，6G需要依靠可持续的解决方案来应对不断增长的交通需求和人口密度，同时提供颠覆性的能力，如感知互联网的实现。6G-REFERENCE设想的解决方案包括用于联合相干通信和毫米波传感的超密集无蜂窝部署，平衡了6ghz以下（例如减少路径损耗）和毫米波（例如宽带宽）范围的优势。这些系统面临五个基本挑战：(i)分布式无线电单元之间需要精确同步；（ii）前传数据分发；综合感应能力；低复杂性/低成本/低消耗无线电；(v)与其他服务共存。6G-REFERENCE将开发针对所有这些问题的集成电路和天线组件解决方案。它将设计频率/时间同步电路和基于全双工的新的连续同步框架。事实上，针对这种方案，将开发全双工解决方案，以及级联无线电单元之间有效的前传数据分发，并实现集成单站雷达传感。除此之外，在传感领域，6G-REFERENCE将探索集成在天线阵列中的环境传感器，重用同步框架进行精确定位，并开发新的阵列解决方案，如调频，以控制成本和功耗提供空间超分辨率。后者也将成为时间调制阵列的目标，提供高效的单射频链多波束操作，以及扩展小型FMA/TMA阵列功能的可重构智能表面。最后，将开发动态中频和天线滤波，以实现有效的频谱共存方案。6G- reference的最终目标是开发硬件使能器，最终可以构成未来6G分布式无线电的参考设计。

In urban areas, 6G will need to rely on a sustainable solution to cope with the ever-increasing traffic demands and population densification, while providing disruptive capabilities like the materialization of the internet of sense. The solution envisioned by 6G-REFERENCE consist of ultra-dense cell-free deployments for joint coherent communications and sensing at cm-waves, which balance the benefits of sub-6GHz (e.g. reduced pathloss) and mm-wave (e.g. wide bandwidth) ranges. These systems face five fundamental challenges: (i) the need of accurate synchronization among distributed radio units; (ii) fronthaul data distribution; (iii) integration of sensing capabilities; (iv) low complexity/cost/consumption radios; and (v) coexistence with other services. 6G-REFERENCE will develop integrated circuit and antenna component solutions addressing all of them. It will design frequency/time synchronization circuits and a new continuous synchronization framework based on full-duplex. Indeed, full-duplex enabling solutions will be developed targeting such scheme as well as efficient fronthaul data distribution among cascaded radio units, and for enabling integrated monostatic radar sensing. Besides these, on the sensing domain, 6G-REFERENCE will explore environmental sensors integrated in the antenna estates, reuse the synchronization framework for accurate localization, and develop new array solutions like frequency modulation providing spatial superesolution at a contained cost and power consumption. The latter will be also targeted by time modulated arrays providing efficient single-RF chain multibeam operation as well asreconfigurable intelligentsurfaces extending the capabilities ofsmall FMA/TMA arrays. Finally, dynamic IF and antenna filtering will be developed to enable efficient spectrum coexistence schemes. The ultimate goal of 6G-REFERENCE is to develop hardware enablers that could end up constituting a reference design of future 6G distributed radios.