无线传感器网络中确保端到端传输质量的自适应调制缩放技术

在满足数据收集任务的时延要求及可靠性要求的前提下最小化能量消耗是传感嚣网络设计中的一个关键问题。选取不同的调制级数(即调制时的星座图大小，每符号位数)可以获得不同程度的能量节省，但引入不同程度的时延的同时也会造成不同程度的丢包。本文提出了一种优化模型在满足数据收集任务的时延要求及可靠性要求的前提下，最优选取各节点的调制级数以最小化网络能耗延长网络生命期。并在此基础之上提出了一个集中式控制算法以根据网络状况自适应地调节各节点的调制级数。实验表明本算法在所考查的各种网络环境下都能明显减少能耗，可以用该模型来确定时延及丢包率对能耗影响的敏感区。另外我们发现，如果将节点的服务率设置为与节点的包到达率近似成比例，在大多数情况下都能够获得好的节能效果。

The Adaptive Modulation Scaling Technology Ensuring End-to-End Transmission Quality in Wireless Sensor Networks

To minimize the energy consumption without violating the end-to-end transmission latency constraint and reliability requirement of application is a key concern of data gathering in wireless sensor networks. Adaptively ad- justing modulation level (number of bits per symbol) of each node will save energy significantly but introducing some latency and packet loss. This paper provides an optimization model to minimize energy consumption and prolong the lifetime of network under the transmission requirement of application by optimally choose the modulation level of each node. A centralized optimization mechanism is developed based on this model,which adaptively adjusts the modulation levels according to the state of network. Experimental results show that the management mechanism saves significant energy in all the investigated scenarios. And the model can be used to determine the sensitive ranges of constraints on latency and packet loss,which have large impacts on the overall energy consumption. Another interesting finding is that the optimal packet service rate of each node is proportional to the packet arrival rate in most scenarios.