| 摘要: |
| 以典型工业环境中的无线传感器网络应用为测试背景,发现IEEE 802.15.4 无线链路质量存在一定的波动跳变现象,并且数据包丢失存在突发性.采用数据轨迹驱动和统计推断的建模方法,对链路层数据传输轨迹中的丢包间隔进行统计并推断其分布特征,发现其符合Pareto 分布,分布参数反映了不同丢包率下的丢包间隔分布情况.将分布参数与丢包率相同的独立同分布的分布参数之间的差值Dα(相关性距离)作为描述丢包突发性的指标.分析和实验得出,Dα与链路层的重传独立性距离(RID)有着近似的线性关系.在数据链路层利用Dα来优化单跳链路的重传机制,可以提高数据重传的可靠性,通过实验验证,相对于不考虑链路丢包突发性的固定时隙重传机制,实验中所有链路的重传可靠性平均提高6.3%,最高可提高14.5%. |
| 关键词: 无线传感器网络 IEEE 802.15.4 链路突发性建模 丢包间隔 重传可靠性 |
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| 基金项目:国家自然科学基金(61003251); 国家高技术研究发展计划(863)(2011AA040101); 国家教育部博士点基金(20100006110015) |
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| Modeling of Burstiness for IEEE 802.15.4 Radio Link and Optimizing for Retransmission Mechanism in Industrial Environments |
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GUO Zhi-Qiang, WANG Qin, WAN Ya-Dong, WU Long
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School of Computer and Communication Engineering, University of Science and Technology Beijing, Beijing 100083, China
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| Abstract: |
| For the applications of wireless sensor networks in typical industrial environments, the wireless link quality of IEEE 802.15.4 has a certain degree of fluctuation and packets loss appear bursty. In this paper, a data-trace-driven modeling method and statistical inference is adopted for the statistical analysis of the loss interval in link-layer packet transmission traces. The study finds that the loss interval follows Pareto distribution and the distribution parameter reflects the distribution characteristics of loss interval under a different packet loss rate. Take the Dα, namely correlation distance, which is the difference between the sample distribution parameter and that of the independent identical distribution under the same packet loss rate, as the indicator to characterize burstiness of packet loss. Through analysis and experiments, it is indicated that the retransmission independence distance (RID) in the link-layer has an approximate linear relation to the correlation distance. The study designs an optimal data retransmission mechanism using the indicator Dα in single-hop links, which can improve data retransmission reliability. Finally, it is verified by experiments that the average of reliability improvement is 6.3% with the maximum 14.5%, which is relative to the fixed time-slot retransmission mechanism that does not consider the packets loss burstiness. |
| Key words: WSN IEEE 802.15.4 link burstiness modeling loss interval retransmission reliability |
