We propose a novel distributed beamforming framework for UAVs, called SABRE, wherein airborne transmitters synchronize their operations for data communication with target receivers. SABRE chooses the best-suited subset of transmitters that maximizes user-defined QoS, considering relative distances from receivers, traffic characteristics, cumulative SNR desired at the receiver, and individual SNR estimated for each link. This paper makes three main contributions: (i) It shows how to achieve distributed beamforming in challenging, aerial hovering conditions by accurately synchronizing start-times and eliminating relative clock offsets. (ii) It proposes an algorithm with polynomial complexity that groups transmitters and chooses the receiver, maximizing the number of satisfied receivers in each round. (iii) It experimentally validates the concept of aerial beamforming in a testbed composed of four DJI-M100 UAVs in realistic outdoor environments. We follow this up with at-scale emulation involving beamforming with multiple candidate UAV transmitters in Colosseum, the world’s largest RF emulator. SABRE keeps the overall network frame error rate below 10% with a probability of 0.95 and manifests a 40% improvement in meeting user QoS thresholds over classical resource allocation methods. From a community viewpoint, the beamforming code, UAV interfacing designs, and the Colosseum container will be released publicly, allowing further independent investigations.

中文翻译：

---

SABRE：基于群的空中波束形成无线电：实验和仿真


我们提出了一种新颖的无人机分布式波束成形框架，称为 SABRE，其中机载发射器同步其操作，以与目标接收器进行数据通信。 SABRE 选择最适合的发射器子集，以最大限度地提高用户定义的 QoS，同时考虑到接收器的相对距离、流量特征、接收器所需的累积 SNR 以及为每个链路估计的单独 SNR。本文做出了三个主要贡献：（i）展示了如何通过准确同步启动时间和消除相对时钟偏移，在具有挑战性的空中悬停条件下实现分布式波束成形。 (ii)提出了一种具有多项式复杂度的算法，对发射机进行分组并选择接收机，从而最大化每轮中满意的接收机的数量。 (iii) 在由四架 DJI-M100 无人机组成的测试平台上，在真实的室外环境中通过实验验证了空中波束成形的概念。我们随后进行了大规模仿真，涉及在世界上最大的射频仿真器 Colosseum 中使用多个候选无人机发射机进行波束成形。 SABRE 将整体网络帧错误率保持在 10% 以下，概率为 0.95，并且在满足用户 QoS 阈值方面比传统资源分配方法提高了 40%。从社区的角度来看，波束成形代码、无人机接口设计和罗马斗兽场容器将公开发布，以便进一步进行独立调查。