一种基于动态优先级的NB-IoT随机接入算法

Random access algorithm based on dynamic priority in NB-IoT

随着物联网的快速发展,NB-IoT系统的设备数量迅速增加,大规模的随机访问请求极易导致NB-IoT系统过载。为此,文中将LTE系统的扩展访问级别控制(EAB)策略引入NB-IoT系统之中,并根据设备的时延情况引入新的接入优先权动态分类机制来高效地解决海量设备的接入过载问题:首先,定义设备的时延系数为等待时延与最大忍耐时延的比值;然后,根据设备时延系数设计了新的接入优先权分类机制;最后,提出一种基于时延寿命的动态优先级NB-IoT随机接入算法。仿真结果表明,与传统的EAB接入算法相比,文中提出算法的设备接入成功率更高,同时设备的接入时延更低。

With the rapid development of the Internet of Things(IoT),the number of random access devices of the NB-IoT system rapidly increases,large scale access requests can easily lead to overload of the NB-IoT network.For this reason,the extend access barring (EAB) policy of LTE system is introduced into a NB-IoT system,and a new dynamic priority classification mechanism based on the delay of the device is proposed to efficiently solve the problem of access overload of massive devices.Firstly,the delay coefficient of the device is defined as the ratio of waiting delay to the maximum endurance delay.Then,a new access priority classification mechanism is designed according to the device delay coefficient.Finally,a random access algorithm based on dynamic priority in NB-IoT for delay lifetime is proposed.The simulation results show that compared with the traditional EAB access algorithm,the device of the algorithm has a higher success rate of device access and lower access delay.