摘要
随着智慧海洋的发展,水声网络多媒体数据的传输受到学者关注.水声网络高度动态的拓扑导致相邻节点数据传输不完整,压缩的水下图像或视频等数据对重建数据的质量有不同影响,因此水声网络需要具有不等差错保护(Unequal Error Protection,UEP)的编码机制来编解码重要性不等的多媒体数据.递归与限制反馈的在线喷泉码(Recursive Online Fountain Code with Limited Feedback,ROFC-LF)具有开销低、反馈少及编译码简单等特点,因此适用于水声网络.本文针对水声信道带宽窄、延时长及能量受限等特点,系统地分析了ROFC-LF编码机制建立阶段存在的环问题.针对ROFC-LF编码存在的环和无法提供UEP功能这两个问题,本文提出了两个优化目标.此外,还提出了具有不等差错保护的避环ROFC-LF编码机制.该编码机制减少了由于建立阶段最大组件存在环引起的无用编码包的数量,进而降低了网络能耗.不等差错保护的避环ROFC-LF编码机制在建立阶段和完成阶段分别采用权重策略和数据优先级策略来实现UEP特性,并利用随机图理论对该编码机制进行理论分析,理论结果和仿真实验结果一致.结果表明:该编码机制能够快速的恢复重要数据的同时,降低了编码包的数量,适用于网络拓扑结构动态变化的水声网络传输重要性不等的多媒体数据.
With the development of smart ocean,the transmission of multimedia data in underwater acoustic net⁃works(UANs)has received much attention from scholars.The highly dynamic topology of UANs leads to incomplete data transmission between neighboring nodes,and the different portions of compressed data such as underwater images or videos have different effects on their reconstruction quality.Hence,UANs require coding mechanisms with unequal error protec⁃tion(UEP)to encode and decode multimedia data.The recursive online fountain code with limited feedback(ROFC-LF)has the advantages of low overhead,less feedback and simple compiled codes,which is suitable for UANs.Combined with the characteristics of underwater acoustic channels,such as narrow bandwidth,long delay and energy limitation,this paper systematically analyzes the problem of the cycles existing in the build-up phase of ROFC-LF and proposes two optimization objectives to address the cycle problem as well as the UEP problem.In addition,a circle-avoidance ROFC-LF with UEP is presented for UANs.This coding mechanism reduces the number of useless encoded packets due to the presence of cycles in the largest component during the the build-up phase,which in turn decreases the energy consumption.To achieve the UEP property,a weighted-selection strategy is used in the build-up phase,whereas a priority strategy is employed in the completion phase.The proposed coding mechanism is analyzed based on the random graph theory,and the theoretical re⁃sults are consistent with the simulation experimental results.The results show that the proposed coding mechanism can quickly recover important data while reducing the number of coded packets,and is suitable for transmitting multimedia data of varying importance in UANs with dynamically changing network topology.
作者
柳秀秀
杜秀娟
韩多亮
LIU Xiu-xiu;DU Xiu-juan;HAN Duo-liang(College of Computer,Qinghai Normal University,Xining,Qinghai 810008,China;Qinghai Provincial Key Laboratory of IoT,Xining,Qinghai 810008,China;The State Key Laboratory of Tibetan Intelligent Information Processing and Application,Xining,Qinghai 810008,China)
出处
《电子学报》
EI
CAS
CSCD
北大核心
2024年第8期2591-2606,共16页
Acta Electronica Sinica
基金
青海省自然科学基金(No.2024-ZJ-929)
国家自然科学基金(No.61962052)。
关键词
水声网络
ROFC-LF
不等差错保护
避环
权重
数据优先级
underwater acoustic networks
recursive online fountain code with limited feedback
unequal error pro⁃tection
circle-avoidance
weighted-selection
data priority
