In this paper we focus on a feedback mechanism for unsourced random access (URA) communications. We propose an algorithm to construct feedback packets broadcasted to the users by the base station (BS) as well as the feedback packet format that allows the users to estimate their channels and infer positive or negative feedback based on the presented thresholding algorithm. We demonstrate that the proposed feedback imposes a much smaller complexity burden on the users compared to the feedback that positively acknowledges all successful or negatively acknowledges all undecoded users. We also show that the proposed feedback technique can lead to a substantial reduction in the packet error rates and signal-to-noise ratios (SNR)s required to support various numbers of active users in the system.

翻译：在本文中,我们侧重于无源随机访问通信的反馈机制。我们提出一个算法,以构建基地台向用户广播的反馈包,以及反馈包格式,使用户能够根据所提出的阈值算法估计其频道,并推断出正面或负面反馈。我们证明,与积极承认所有成功或负面承认所有未解码用户的反馈相比,拟议的反馈给用户带来的复杂负担要小得多。我们还表明,拟议的反馈技术可以大幅降低支持系统内各种活跃用户所需的组合错误率和信号对噪音比率。