基于LoRaWAN无线抄表应用场景的MAC层协议设计  

Design of MAC Layer Protocol for Wireless Meter ReadingApplication Scenarios Based on LoRaWAN

作　　者：李晶[1] LI Jing(School of Communication and Information Engineering,Nanjing University of Posts and Telecommunications,Nanjing 210003,China)

机构地区：[1]南京邮电大学通信与信息工程学院,江苏南京210003

出　　处：《无线电通信技术》2023年第6期1125-1133,共9页Radio Communications Technology

摘　　要：LoRaWAN协议上行采用纯ALOHA(Pure ALOHA,P-ALOHA)的方式发送数据,信道碰撞率高且利用率低,不适合用于无线抄表等应用场景。针对LoRaWAN协议的局限性,提出了一种适合于无线抄表应用场景的介质访问控制(Media Access Control, MAC)层协议。该MAC层协议设计了超帧的结构,采用时隙ALOHA(Slot ALOHA,S-ALOHA)协议与时分多址(Time Division Multiple Access, TDMA)协议相结合的混合式接入机制,并在信道上融入突发业务,节点可以根据TDMA时隙的使用情况,灵活决定用于竞争的时隙;设计了将节点分散到一个超帧的不同复帧发送数据的方法;利用超帧的结构,能使具有不同发送周期的节点在同一个信道上工作;根据功能需求对帧结构进行了改进。仿真结果表明,与P-ALOHA协议相比,该MAC层协议能很好地降低碰撞率,提高信道利用率,并且能很好地解决因大量节点同时发送数据而造成的信道瘫痪问题。LoRaWAN protocol uses Pure ALOHA(P-ALOHA)to send data,which has a high channel collision rate and low utilization rate,making it unsuitable for applications such as wireless meter reading.Aiming at the limitation of LoRaWAN protocol,a Medium Access Control(MAC)layer protocol suitable for wireless meter reading application scenarios is proposed.The media access control layer protocol designs a superframe structure and adopts a hybrid access mechanism that combines Slot ALOHA(S-ALOHA)protocol with Time Division Multiple Access(TDMA)protocol.The transmission of burst service data is integrated into the channel,and nodes flexibly determine the time slot range for competition based on the usage of TDMA time slots.A method is designed for dispersing nodes into different multiframes of a superframe to send data.By utilizing the structure of superframes,nodes with different transmission periods can work on the same channel.And the frame structure has been improved according to functional requirements.Simulation results show that compared with P-ALOHA protocol,this MAC layer protocol can effectively reduce collision rate,improve channel utilization,and solve the problem of channel paralysis caused by a large number of nodes sending data simultaneously.

关 键 词：LoRaWAN 无线抄表应用场景 混合式接入机制 超帧 介质访问控制层协议 

分 类 号：TN911.4[电子电信—通信与信息系统]