卫星物联网中多域联合活跃用户辨识方法

Multi-domain joint active user identification method in satellite Internet of Things

在卫星物联网上行免授权接入场景下,用户直接将数据发送给卫星,不需要进行动态资源分配,这将导致接收端难以事先区分活跃用户。为恢复传输数据,需进行活跃用户检测(AUD)。目前,多使用码域方法进行活跃用户辨识,但物联网密度远超移动通信用户,仅依靠码域辨识会导致地址码维度激增,降低帧效率,并且较多采集类与监测类物联网终端自身能力弱,无法实现自身位置的上报,导致这一维接入辅助信息的缺失,不利于活跃用户检测的性能提升。本文面向未来星载相控阵发展趋势,引入空域辨识思想,通过空域与码域的级联辨识,采用多域联合方法进行活跃用户检测。仿真结果表明,本文方法能够提升地址码冲突时的辨识能力。

In the uplink grant-free access scenario of the satellite Internet of Things(IoT),users directly send data to the satellite without the need for dynamic resource allocation,which makes it difficult for the receiving end to distinguish active users in advance.To recover the transmitted data,Active User Detection(AUD)is required.Currently,code domain methods are commonly used for active user identification,but the density of IoT devices far exceeds that of mobile communication users.Relying solely on code domain identification can lead to a dramatic increase in the dimension of address codes,reducing frame efficiency.Moreover,many collection and monitoring IoT terminals have weak capabilities and cannot report their own positions,resulting in the loss of this dimension of access auxiliary information,which is not conducive to improving the performance of active user detection.Aiming at the future development trend of satellite-borne phased array,this paper introduces the concept of spatial domain identification.By cascading identification in the spatial and code domains,a multi-domain joint method is used for active user detection.Simulation results show that the proposed method can enhance the identification capability when there is an address code conflict.