窄带物联网上行时频资源利用率研究

Time-frequency resource utilization of narrow-band Internet of Things

在覆盖类别更新机制的基础上,以前导码传输重复次数为变量建立了窄带物联网(Narrow-Band Internet of Things,NB-IoT)时频资源利用率和随机接入成功概率的多目标优化模型。给出了时频资源利用率和随机接入成功概率之间的折中关系及优化算法,分析了前导码重复传输次数对系统性能的影响。数值分析表明:时频资源利用率随前导码重复传输次数的降低而增加,通过前导码传输重复次数和各覆盖类别最大传输次数的配合使用,低负载场景的时频资源利用率可达到0.98。满足随机接入成功率大于0.99时的高负载场景最大值可达0.72。

On the basis of the coverage class updating mechanism,a multi-objective optimization model of Narrow-Band Internet of Things(NB-IoT) is established with the preamble repetition as variable,average access success probability and uplink time-frequency resource utilization rate as objective.The optimal configuration of the repetition for typical multiplexing scenario without considering the maximum retransmission of preambles is solved and the effects of the maximum retransmission of preamble on the optimal configuration of the repetition are analyzed.Simulation results show that the time-frequency resource utilization rate decreases with the increase of the repetition.The coordination of maximum retransmission and repetition of each coverage class can achieve the ultra-low power consumption and high uplink time-frequency resource utilization rate with the probability of success of random access being satisfied.The time-frequency resource utilization of the low RACH load scenario can reach 0.98.A high RACH load scenario with a random access success rate greater than 0.99 can reach a maximum of 0.72.