一种卫星物联网免授权随机接入方案

Grant-Free Random Access in LEO Satellite-Enabled Internet-of-Things

随着低轨卫星通信系统的快速发展,基于低轨卫星星座的物联网凭借其无缝覆盖的优势得到了广泛的关注,其为偏远地区边缘设备的接入提供了一个有效的方案。面对低轨卫星物联网中大量随机接入的物联网设备,引入了一种免授权的随机接入机制,以减小接入时延,提高接入效率。在此基础上,针对引入免授权随机接入机制带来的调度信令缺乏,并由此导致活跃设备序号及相应的信道状态信息未知的问题,提出了一种基于压缩感知的联合活跃设备检测与信道估计方案,并进行仿真实验验证。仿真结果表明,提出的方案在较小导频开销的情况下即能取得满意的活跃设备检测与信道估计性能。

With the rapid development of low-earth-orbit(LEO)satellite constellation,the LEO satellite-enabled Internet-of-Things(IoT)has attracted extensive attention due to its advantages of seamless coverage,which provides a promising solution for the access of IoT devices in remote areas.With the massive random connectivity in LEO-IoT,a grant-free random-access scheme is introduced to significantly reduce access delay and improve access efficiency.Without scheduling signaling overhead in the grant-free random-access scheme,a joint active device detection and channel estimation method based on compressive sensing is proposed to detect the unknown active devices and their corresponding channel state information.Simulation results demonstrate the effectiveness of the proposed method,where it can guarantee satisfactory performance with the greatly reduced pilot symbols overhead.