Computer Engineering and Applications ›› 2020, Vol. 56 ›› Issue (24): 95-101.DOI: 10.3778/j.issn.1002-8331.1911-0338

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Research on Channel Access Method of LoRaWAN Based on LBT-SA

YU Zhong, GU Renbin, FAN Jiulun   

  1. School of Communications and Information Engineering, Xi’an University of Posts & Telecommunications, Xi’an 710061, China
  • Online:2020-12-15 Published:2020-12-15



  1. 西安邮电大学 通信与信息工程学院,西安 710061


The pure ALOHA channel access method defined in the standard LoRaWAN protocol can cause a lot of collisions and transmissions failed when in a heavy load, it challenges the scalability and reliability of the LoRa network greatly. A new channel access method, LBT-SA (Listen Before Talk combined with Simulated Annealing), is proposed. This method reduces the probability that multiple devices access the channel by detecting the channel before sending, and searches for a smaller backoff time by taking the backoff time required for successful transmission as the initial value. Simulation results show that LBT-SA can not only maintain the packet delivery rate provided by LBT with binary exponential backoff algorithm, but also minimize the unnecessary backoff in the transmission, thus reducing the delay. In a scenario where up to 10,000 end-devices access a single gateway, the average backoff time of the algorithm is reduced by at least 16.38%.

Key words: LoRaWAN, channel access method, listen before talk, simulated annealing algorithm, competition window


标准LoRaWAN协议中定义的纯ALOHA信道接入方法在网络负载较大时会造成大量碰撞,使LoRa网络的可扩展性和可靠性受到极大挑战。为此提出了一种将先听后说与模拟退火相结合(Listen Before Talk combined with Simulated Annealing,LBT-SA)的LoRa信道接入方法。该方法通过在设备发送之前先监听信道,降低信道被同时接入的概率,并以成功传输所需退避时间为初始值,搜索更小的退避时间。仿真结果表明,LBT-SA和基于二元指数退避算法的先听后说(Listen Before Talk,LBT)方法在包成功传输率方面保持了高度的一致,并且LBT-SA在周期传输过程中逐渐减少了不必要的退避时间,从而减少了时延。在多达10 000个终端接入单个网关的场景中,该算法的平均退避时间至少降低了16.38%。

关键词: LoRaWAN, 信道接入方法, 先听后说, 模拟退火算法, 竞争窗口