Abstract: Aiming at the different QoS requirements for various traffic transmission level in wireless sensor networks，a differentiated services algorithm for various traffic transmission has been introduced—EMHNS.The algorithm chooses appropriate forwarding nodes based on various traffic transmission levels.So it can achieve the minimum time delay for real-time traffic transmission.The influence of delay is not the primary factor for best-effort traffic transmissions，the network energy load balance should be taken into account heavily when the best-effort traffic transmits.The simulation results indicate that this algorithm can achieve lower time delay for real-time traffic than Directed Diffusion （DD） algorithm，and extend the lifetime of the network.

Key words: wireless sensor networks, real-time traffic, best-effort traffic, differentiated services, time delay, energy load balance

摘要： 针对无线传感器网络中不同等级业务在传输过程中对QoS的不同要求，提出了一种适合无线传感器网络中不同业务的区分服务算法——EMHNS算法。该算法根据不同等级的业务来选择合适的转发节点，从而保证实时业务传输的时延能够达到最小，而尽力而为业务传输时时延不是考虑的主要因素，在传输尽力而为业务的时候重点考虑网络能耗均衡。仿真结果表明，与定向扩散协议相比，该算法能降低实时业务的端对端延时，并使网络生存期得到提高。

关键词: 无线传感器网络, 实时数据, 尽力而为数据, 区分服务, 时延, 能耗均衡