中文摘要：

虚拟（协作式）MIM0技术被认为是传感器网络中有效的节能解决方案之一，然而，现有虚拟MIMO传输策略的设计大多只关注如何有效降低网络能耗，而很少关注反映网络性能的其他指标，例如网络效用（Network Utility），该指标反映了网络数据采集和传输量的多少．为了联合优化网络效用和网络生存时间这两个网络性能参数，本文首先分析虚拟MIMO传输能耗特点，然后基于网络效用最大化（Network Utility Maximization）思想对虚拟MIM0传感器网络进行联合网络生存时间和网络效用的优化建模．在该模型的求解过程中，通过使用对偶分解技术将原需要集中计算的优化问题分解为可以在不同节点上进行计算的子优化问题，并得出一种联合优化网络效用和生存时间的分布式优化算法．该算法的仿真结果显示，网络中的虚拟MIMO节点仅需要交互邻居节点信息，通过有限次的迭代计算，就能收敛到全局最优的发送速率以及功率值，从而使系统总的效用和网络生存时间之间能够达到帕累托（Pareto）最优平衡．

英文摘要：

Virtual MIMO technique is considered as one of the effective solutions to minimize the energy consumption in wireless sensor networks. However, the existing virtual MIMO based protocols only concern about reducing the energy consumption, but not consider the network performance which depends on the total amount of transferred data. In this paper, in order to minimize the network energy consumption and meanwhile maximize the virtual MIMO network performance, we propose a joint network utility and lifetime optimization model based on NUM （network utility maximization）. In our design, we use the dual decomposition technique to turn the primal centralized optimization problem into several dual problems that could be calculated on the different virtual MIMO nodes, and thus get a distributed optimization algorithm. Simulation results show that, by using our distributed algorithm, the virtual MIMO nodes in the network can converge to the optimal source data rate and transmit power. The Pareto optimal tradeoff between the network utility and the network lifetime can be achieved.