Abstract: Due to the lossy characteristic of wireless links in Low-power and Lossy Network（LLN）, the load balancing cannot be achieved effectively in high-load scenarios. Therefore, a load balancing-based routing protocol for LLN in high load scenarios is proposed（HSLB-RPL）. In this protocol, the expected transmission count of the current node and its alternative parent node is comprehensively considered to avoid that the alternative parent node with a large expected transmission count is selected as the optimal parent; when it is detected that the load of a node is heavy, the time interval for sending DIO control message of the node should be adjusted to reduce the probability that it is selected by the neighboring node as the best parent node; when the network congestion occurs, a Network Congestion Notification（NCN） message is designed to notify the current network congestion status timely. Simulation results show that compared with the existing protocols, the HSLB-RPL protocol can effectively achieve load balancing, in which the network lifetime is increased by 23.57%, the average throughput of the root node is increased by 14.52%, and the normalized control overhead is lower by 12.87%.

Key words: Low-power and Lossy Network（LLN）, routing protocol, high-load scenario, load balancing, expect transmission count

摘要： 针对低功耗有损网络（Low-power and Lossy Network，LLN）中由于无线链路的有损特性导致在高负载场景下无法较好地实现负载均衡的问题，提出一种高负载场景下基于负载均衡的LLN路由协议（HSLB-RPL）。在该协议中，为了避免期望传输次数较大的备选父节点被选作为最优父节点，综合考虑当前节点和其备选父节点的期望传输次数；当检测到节点负载较重时，为了降低其被邻居节点选作为最优父节点的概率，对其DIO控制消息的发送时间间隔进行调整；当节点发生网络拥塞时，设计一种网络拥塞通告消息（NCN），及时地对当前网络拥塞状态进行通告。仿真结果表明，相对于已有协议，HSLB-RPL协议能够有效地实现负载均衡，其中网络平均寿命延长了23.57%，根节点平均吞吐量提高了14.52%，归一化控制开销较低了12.87%。

关键词: 低功耗有损网络, 路由协议, 高负载场景, 负载均衡, 期望传输次数