Sensor networks are used for observing some region of interest. Sensors sense different physical quantities and send to base station or sink. The tree based networks with TDMA as MAC protocol are preferable because of simplicity of tree and guaranteed data access in TDMA. Often sensor networks are multi-sink and multi-attribute networks. Multi-sink network means more than one sinks are present and so multiple sink-rooted trees are formed. When more than one types of nodes are deployed in the network, the network is known as heterogeneous network or multi-attribute network. Sometimes node density or heterogeneity is not uniform across entire network. As a result of non-uniform node distribution or non-uniform heterogeneity distribution, schedule lengths of sink-rooted trees are very different. Nodes part of trees with small schedule length will get more frequent transmission turns compared to those which belong to trees with large schedule length. To ensure fairness in terms of transmission opportunities, it is desired that schedule lengths should be balanced. In this work, an algorithm named as Schedule Length Balancing for Multi-sink HeTerogeneous networks (SLBMHT) is presented to balance schedule lengths. The SLBMHT algorithm is evaluated through simulations. It is found that the SLBMHT algorithm results in 8–56% reduction in schedule length difference of trees. It also results in 2–17% energy savings during data transmission phase. Only demerit is increase in control overhead. But as resulting increase in energy consumption is not much, it is overcome by savings in data energy consumption. Thus network lifetime is likely to increase.

传感器网络用于观察某些感兴趣的区域。传感器感应不同的物理量，然后发送到基站或接收器。具有TDMA作为MAC协议的基于树的网络是优选的，因为树的简单性和TDMA中保证的数据访问。传感器网络通常是多接收器和多属性网络。多接收器网络意味着存在多个接收器，因此形成了多个以接收器为根的树。当在网络中部署不止一种类型的节点时，该网络称为异构网络或多属性网络。有时，节点密度或异构性在整个网络中并不统一。由于节点分布不均匀或异质性分布不均匀，汇聚根树的调度长度非常不同。与属于大调度长度的树的那些节点相比，具有小调度长度的树的节点的节点将获得更频繁的传输转向。为了确保在传输机会方面的公平，期望时间表长度应保持平衡。在这项工作中，提出了一种称为多汇聚异构网络调度长度平衡的算法（SLBMHT），以平衡调度长度。SLBMHT算法通过仿真进行评估。结果发现，SLBMHT算法可将树木的计划长度差异减少8–56％。在数据传输阶段还可以节省2-17％的能源。唯一的缺点是控制开销的增加。但是，由于能耗的增加并不多，因此可以通过节省数据能耗来解决。