无线传感器网络（WSN）是由大量的传感器节点通过无线通信方式自组织构成的网络，一般部署在环境复杂的地区，节点携带的电池能量有限且难以更换，节能成为无线传感器网络的首要问题。把基于多输入多输出（MIMO）的协作分集技术应用到WSN中，可以有效地降低网络能耗。 首先对WSN和MIMO系统的特点进行了概括，分析了MIMO技术中STBC和V-BLAST两种系统的编译码算法，给出了MIMO技术和WSN的结合方法。 然后重点研究了基于STBC的协作分集技术在WSN中的应用。提出了收端分集协作和STBC协作的系统模型，通过分析每个传感器节点的电路能耗和传输能耗，分别得到了两种协作方式下网络的总能耗。通过研究接收端协作节点个数变化对网络总能耗的影响，得到了两种协作方式在不同长途传输距离下的最优协作节点个数。研究表明，最优协作节点个数随长途传输距离的增大而增加，优化后的收端分集协作总比传统的无协作方式能耗要低，而当传输距离大于一个门限值时，优化后的STBC协作优于收端分集协作。 最后通过分析QAM调制阶数对本地通信和长途通信网络能耗的影响，联合优化调制阶数和接收端协作节点个数，得到了不同长途传输距离下的最优协作传输方案。研究表明，长途传输距离较大时，相比无协作方式，最优STBC协作能够节省90%以上的能量。

Wireless Sensor Networks (WSN) is a self-organization network. It is composed of large amounts of sensor nodes through wireless communication. Because Wireless Sensor Network is generally deployed in very complex environment and meanwhile sensor batteries are energy-constrained and difficult to replace, energy efficiency is a principle issue. To reduce energy consumption, cooperative diversity technology based on Multiple-Input Multiple-Output (MIMO) is introduced into WSN. Firstly, this paper summarizes characteristics of WSN and MIMO systems. Coding and decoding algorithms of Space-Time Block Code (STBC) and Vertical-Bell labs Layered Space-Time Code (V-BLAST) in MIMO are analyzed, and methods combined MIMO technology and WSN are presented. Then cooperative diversity technology based on STBC is studied. Propose system model of cooperative diversity at the receiver and STBC cooperation. By analyzing the circuit energy consumption and the transmission energy consumption of each sensor nodes, total energy consumption of the two cooperative models is presented, respectively. Influence of the number collaborative nodes number on total energy consumption is studied to get the optimal collaborative nodes number of the two model with different transmission distances. Results show that the optimal collaborative nodes number changes with various transmission distances. It also shows that the optimized STBC cooperation can save more energy for long-haul distances larger than a given threshold. At last, influence of constellation size on total energy consumption of local communication and long haul communication is presented, respectively. Optimal transmission scheme under different long-haul transmission distances is obtained by combing constellation size and the number of collaborative nodes. Simulation shows that optimal STBC cooperation can save more than 90% energy than traditional system.