In this paper,a contention-based connection-free transmission scheme is proposed to meet the stringent requirements of ultra-reliability and low-latency for critical machine-type communication(cMTC).To improve reliabi...In this paper,a contention-based connection-free transmission scheme is proposed to meet the stringent requirements of ultra-reliability and low-latency for critical machine-type communication(cMTC).To improve reliability,we design multiple independent sparse orthogonal pilots(MISOP)to significantly reduce the probability of pilot collision to the order of 10^(−5).Besides,the advancements of massive MIMO(mMIMO)are exploited to further enhance the reliability.To achieve low latency,connection-free slot-based one-shot transmission without retransmissions is adopted.On the receiver side,single round of multi-user detection(MUD)without interference cancellation(IC)can reduce the processing delay.The imprecise synchronization between cMTC device and the gNB in connection-free transmission,e.g.,time and frequency offsets,are also considered.The simulation results shows that the proposed scheme can well satisfy the ambitious requirements of cMTC,and has the potential applications in supporting massive cMTC devices in 6G.展开更多
针对海量机器类通信(Massive Machine Type Communications,mMTC)场景下传统随机接入存在大量前导碰撞问题,提出了一种对终端侧和基站侧的接入改进算法,利用前导标记序列和固定位置随机接入终端的定时提前(Timing Advance,TA)信息,使得...针对海量机器类通信(Massive Machine Type Communications,mMTC)场景下传统随机接入存在大量前导碰撞问题,提出了一种对终端侧和基站侧的接入改进算法,利用前导标记序列和固定位置随机接入终端的定时提前(Timing Advance,TA)信息,使得基站能合理地确定应该向哪些终端回复随机接入响应消息,避免碰撞终端占用资源发送消息3(Message 3,Msg3),实现前导高效利用。仿真表明,该算法在均匀分布和Beta分布接入模型下均能有效降低前导碰撞概率,提高终端的接入成功率,并且拥有合理的平均接入时延。展开更多
基金supported by the Key-Area Research and Development Program of Guangdong Province under Grant 2019B010157002the National Key Research and Development Program of China under grant 2020YFB1807202.
文摘In this paper,a contention-based connection-free transmission scheme is proposed to meet the stringent requirements of ultra-reliability and low-latency for critical machine-type communication(cMTC).To improve reliability,we design multiple independent sparse orthogonal pilots(MISOP)to significantly reduce the probability of pilot collision to the order of 10^(−5).Besides,the advancements of massive MIMO(mMIMO)are exploited to further enhance the reliability.To achieve low latency,connection-free slot-based one-shot transmission without retransmissions is adopted.On the receiver side,single round of multi-user detection(MUD)without interference cancellation(IC)can reduce the processing delay.The imprecise synchronization between cMTC device and the gNB in connection-free transmission,e.g.,time and frequency offsets,are also considered.The simulation results shows that the proposed scheme can well satisfy the ambitious requirements of cMTC,and has the potential applications in supporting massive cMTC devices in 6G.
