移动通信的快速发展和智能终端设备的大量普及带来无限流量的爆炸性增长，给无线网络系统带宽造成巨大的冲击。单纯依靠蜂窝移动网络已无法满足海量的用户需求，将更多流量分流到Wi-Fi网络成为不可避免的选择，这将给无线局域网络的传输带宽带来新的挑战。当前无线局域网络中用于提升传输性能的功率控制机制，存在传输带宽不能充分利用、数据冲突概率增加的问题。本项目针对此问题进行研究，分析影响网络吞吐量的多个关键问题和改进点，设计一套完善的物理层与MAC层相结合的跨层协议，提升无线网络整体传输性能。我们首先研究物理层技术以减小控制帧引入的开销、同时提高控制信息传输的有效性，在此基础上设计跨层协议，在最大化节点并发传输的同时有效避免干扰，最后基于以上协议搭建无线局域网络原型系统，验证整个协议在实际网络环境下的有效性以及各种性能参数的影响。

The rapid development of mobile communications and smart devices results in the explosive growth of mobile data traffic, which current cellular networks cannot support. It is a good choice to offload part of the data traffic to wireless local area networks, and this method forces WLANs to further improve the network throughput to meet the customer's requirement. The current power control mechanism improves the network performance through dynamically adjusting the transmission power. However, this mechanism wastes the channel bandwidth and induces a large number of collisions. This project makes a study of the current power control mechanism, aims to design a novel cross-layer protocol to improve the network throughput through benefiting from both the physical layer and the MAC layer design. We will design a physical layer mechanism to both reduce the transmission overhead induced by the control frames and increase the efficiency of the control information; we will then design a cross-layer protocol to both increase concurrent transmission opportunities and avoid interference; we will also implement a prototype for the proposed scheme to measure its effectiveness in real networks. All these outcomes will make important contributions to the improvement of the overall performance of future wireless networks.