Routing and hotspot are considered among the key issues in Wireless Sensor Networks (WSNs). Several routing protocols have been proposed; yet they suffer from the lack of fault tolerance, the uneven load balancing and the local optimal solution issues. To fix these issues, we propose in this paper an algorithm named Energy-efficient Cluster-based Routing Protocol using Unequal Clustering and improved Ant Colony Optimization (ACO) techniques (ECRP-UCA). ECRP-UCA divides the network into unequal clusters based on residual energy, distance to the sink, number of neighbor nodes, and a new parameter named number of backward relay nodes in previous round to properly balance the load among Cluster Heads (CHs). We propose also a batch-based clustering method that allows the network to function several rounds without requiring control overhead for its configuration. Additionally, we devise an improved ACO based routing technique for efficient and reliable inter-cluster routing from CHs to the sink. In this algorithm, the heuristic function is formulated considering the energy of next hop sensor node, distance from the current sensor node to the next sensor node and the latter to the destination, and the new parameter Number of Preferred Probable Relay Nodes (NPPRN). By using NPPRN, the ants have the probability to follow other paths, which improves the algorithm’s ability to obtain the optimal global solution and protect the algorithm from converging quickly into the optimal local solution. Moreover, the ant searching direction is improved. The proposed routing protocol is intensively experimented and compared with recent and relevant existing protocols. The simulation results show that the proposed ECRP-UCA outperforms these protocols in terms of various interesting metrics.

路由和热点被视为无线传感器网络（WSN）中的关键问题。已经提出了几种路由协议。但是他们却缺乏容错能力，不均衡的负载平衡和局部最优解决方案问题。为了解决这些问题，我们在本文中提出了一种算法，该算法使用不均等聚类和改进的蚁群优化（ACO）技术（ECRP-UCA）进行了基于能效聚类的路由协议。ECRP-UCA根据剩余能量，到汇点的距离，邻居节点的数量以及上一轮中名为反向中继节点的数量的新参数将网络划分为不相等的群集，以适当地平衡群集头（CH）之间的负载。我们还提出了一种基于批处理的群集方法，该方法允许网络运行数轮而无需对其配置进行控制。此外，我们设计了一种改进的基于ACO的路由技术，以实现从CH到接收器的高效，可靠的集群间路由。在该算法中，启发式函数的制定考虑了下一跳传感器节点的能量，从当前传感器节点到下一个传感器节点的距离，以及从下一传感器节点到目的地的距离，以及新的参数“首选可能的中继节点数”（NPPRN）。通过使用NPPRN，蚂蚁有可能遵循其他路径，从而提高了算法获得最佳全局解的能力，并保护了算法免于快速收敛到最佳局部解。而且，蚂蚁搜索方向得到改善。对提出的路由协议进行了深入的实验，并与最新的和相关的现有协议进行了比较。仿真结果表明，提出的ECRP-UCA在各种有趣的指标方面都优于这些协议。