面向Critical MTC的无连接传输

摘要：关键机器类通信（Critical MTC）对时延和可靠性都有极高的要求。支持海量Critical MTC终端是一个巨大挑战。提出了一种面向海量Critical MTC终端的无连接传输方案。为了降低时延，提出了基于竞争的无连接单次传输方案。为了实现高可靠，设计了具有极低导频碰撞概率的稀疏正交多导频。进一步利用大规模多输入多输出（Massive MIMO）的增益来提高可靠性以及在空域复用大量用户。仿真结果表明，提出的方案可以支持海量Critical MTC终端，同时满足低时延和高可靠的严格要求。

关键词：无连接传输；关键机器类通信；低时延高可靠；导频碰撞；稀疏正交导频

Abstract: Critical machine-type communication (Critical MTC) has extremely high requirements for latency and reliability. Supporting massive critical MTC terminals simultaneously is a huge challenge. A connection-free transmission scheme for critical MTC is proposed. To reduce latency, a contention-based connection-free one-shot transmission scheme is proposed. To achieve ultra-reliability, multiple sparse orthogonal pilots with extremely low probability of pilot collision are designed. Furthermore, the gain of massive multiple-input multiple-output (Massive MIMO) is used to improve reliability and multiplex a large number of users in the spatial domain. The simulation results show that the proposed scheme can support a large number of critical MTC terminals while meeting the stringent requirements of low latency and ultra-reliability.

Keywords: connection-free transmission; critical MTC; ultra reliable low latency; pilot collision; sparse orthogonal pilot