基于RF的无线传感器网络的MAC协议设计

针对传统无线传感器网络能量供应问题，提出了基于射频能量捕获的无线传感器网络介质访问控制（medium access control，MAC）协议。首先在相邻节点之间运用时分多址（time division multiple access，TDMA）技术按时隙分配信道，使数据在源节点到汇聚节点之间无争用传输；同时控制节点在每个周期内消耗的能量，间接调整节点自身的占空比；然后在缓冲区中设置负载阈值作为节点在通信转换角色中的依据，实现节点间的时间同步；最后对各种网络拓扑结构进行实验模拟，评估其延迟率和数据丢包率。实验结果表明：该协议与基于自适应时分多址的介质访问控制（adaptive TDMA-based MAC，AT-MAC）协议相比，不但延迟率低而且网络模拟结构更接近于现实网络场景，可以满足无线传感器网络的性能需求。

MAC Protocol Design for RF-Powered Wireless Sensor Networks

To solve the problem of power supply in traditional wireless sensor network (WSN), a medium access control (MAC) protocol based on RF energy capture is proposed. Firstly, the time division multiple access (TDMA) technology is used to allocate channel according to time slot between adjacent nodes, so that data can be transmitted uncontested between source nodes and sink nodes. At the same time, the energy consumed by nodes in each cycle is controlled, and the duty cycle is adjusted indirectly. Then a load threshold is set in the buffer as the basis of each node’s role in the communication transformation to realize time synchronization between nodes. Finally, experimental simulations of various network topologies are carried out to evaluate delay rate and data loss rate. Experimental results show that, compared with the adaptive TDMA-based MAC (AT-MAC) protocol, the proposed protocol not only has lower latency rate, but also has a network simulation structure closer to the real network scenario, which can meet the performance requirements of wireless sensor networks.