无线传感器网络应用简单Reed-Solomon编码的低能耗和低时延可靠数据收集方案

Energy-Efficient and Low-Delay Reliable Data Gathering Scheme Applying Simple Reed-Solomon Code for Wireless Sensor Network

无线传感器网络的数据链路层和物理层通常采用低功率低数据率的IEEE 802.15.4标准,其节点由能量极为有限的电池供电,且无线链路易丢包,而且在无线传感器网络的一些应用中,需要在给定的时间内将数据汇集到基站,因此,设计一种节能、低时延且可靠的数据收集方案对无线传感器网络的应用极为重要.文中利用Reed-Solomon(RS)编码以提高数据传递可靠性,致力于将能耗、数据收集率、数据收集时延、数据包编码方案整合为一个优化问题;给出了简单RS码字即S-RS码字集合,证明了该码字集合中任何n个码字是线性独立的;详细叙述了基于S-RS码字集合以及段内编码和段间编码的数据收集策略即S-RS数据收集策略的具体步骤;利用概率论推导出了S-RS数据收集策略的总能耗、数据收集率和时延公式,并依此建立了时延和数据收集率约束下的能耗最小化这一优化问题.该优化问题可行解空间很小,可以通过穷举法获得最优解.通过求解该优化问题,节点能够设置最优的数据包编码和重传参数,使得在时延和数据收集率约束下能耗达到最小.数值分析与仿真表明,S-RS数据收集策略能够以较低的能耗达到较高数据收集率和较低时延要求.此外,可以利用导出的总能耗、数据收集率和时延,通过优化S-RS数据收集策略的参数,最大化数据收集率,最小化时延,也可以同时对总能耗、数据收集率和时延中的两者或三者进行优化.

Wireless Sensor Network（WSN）usually adopts the low-power and low-rate IEEE802.15.4standard in its Medium Access Control（MAC）and Physical（PHY）layers.In the WSN,the nodes are powered by battery with very limited energy and wireless links are prone to losing packet.Moreover,in some WSN applications,it is required that the collected data are delivered to the sink node within a given time.Hence,it is extremely significant to develop an energy-efficient,low-delay,and reliable data gathering scheme for WSN applications.In this paper,Reed-Solomon（RS）code is applied to improve the reliability of packet delivery.It aims to form an Optimization Problem（OP）that integrates with energy consumption,Data Gathering Ratio（DGR）,data gathering delay,and coding schemes.The set that contains the Simple ReedSolomon（S-RS）codes is presented,and it is proved that any n members of the set are linearly independent.The data gathering scheme,called the S-RS data gathering scheme,which appliesthe S-RS codes,intra-segment coding,and inter-segment coding,is described in detail.In addition,based on probability theory,the Overall Energy Consumption（OEC）,the DGR,and the data gathering delay under the S-RS scheme are derived,which are used to build the OP that minimizes the OEC with the constraints of DGR and data gathering delay.The number of the feasible solutions of the OP is small such that it can be easily solved using enumeration method.Through solving the OP,the nodes are able to find the optimal values of the parameters for packet encoding and packet retransmissions such that energy consumption in the S-RS scheme is minimized while the constraints of DGR and data gathering ratio are met.Numeric analysis and simulation results show that the S-RS scheme achieves a higher DGR and a lower delay with lower energy consumption.Moreover,the derived OEC,DGR,and data gathering delay can be used in optimizing the parameters by using the S-RS scheme so as to maximize the DGR,minimize the data gathering delay,or optimize two or three of the OEC,DGR,and data gathering delay.