电子学报 ›› 2018, Vol. 46 ›› Issue (12): 2942-2949.DOI: 10.3969/j.issn.0372-2112.2018.12.017

• 学术论文 • 上一篇    下一篇

AdaCode:IEEE 802.11n长距离无线链路自适应编码算法

刘康宁, 赵增华, 王宇   

  1. 天津大学智能与计算学部, 天津 300350
  • 收稿日期:2017-09-20 修回日期:2018-06-01 出版日期:2018-12-25
    • 通讯作者:
    • 赵增华
    • 作者简介:
    • 刘康宁 男.1992年3月出生,河北石家庄人.天津大学智能与计算学部硕士研究生,主要研究方向为无线(长距离) mesh网络和无线ad hoc网络.E-mail:lknwx@tju.edu.cn;王宇 男,1991年2月出生,安徽宿州人.天津大学智能与计算学部硕士研究生,主要研究方向为无线(长距离) mesh网络.E-mail:13920781632@163.com
    • 基金资助:
    • (No.61172063,No.17JCYBJC15500)

AdaCode: Adaptive Codes in IEEE 802.11n Wireless Long-Distance Links

LIU Kang-ning, ZHAO Zeng-hua, WANG Yu   

  1. College of Intelligence and Computing, Tianjin University, Tianjin, 300350, China
  • Received:2017-09-20 Revised:2018-06-01 Online:2018-12-25 Published:2018-12-25
    • Corresponding author:
    • ZHAO Zeng-hua

摘要: 通过在实验床上的大量真实测量,分析了长距离无线链路中导致吞吐率低下的原因,总结了数据帧出错模式和丢包特点.在此基础上,提出了MAC(Media Access Control)层自适应编码算法AdaCode.该算法将帧间编码和帧内编码有机结合起来,帧间编码使用喷泉码LT(Luby Transform)码,帧内编码使用RS(Reed Solomon)码,根据链路中数据帧误比特率和丢包率的实时变化,动态选择最佳编码率,使接收端能够解码出所有数据帧,从而避免重传,极大提升了链路吞吐率.在MATLAB平台上实现了AdaCode,并使用实验床测得的真实数据进行仿真.仿真结果表明在固定物理层发送速率和可变发送速率两种情况下,AdaCode都能有效提升链路吞吐率.

 

关键词: 长距离, 无线Mesh网络, 802.11n, RS码, LT码

Abstract: Through extensive measurements in our wireless long-distance network test-bed, we analyze fundamental reasons that cause low link throughput, and find characteristics of frame error pattern and loss rate. AdaCode is therefore proposed to improve link throughput, which is an adaptive coding algorithm at MAC (Media Access Control) layer. AdaCode integrates inter-coding and intra-coding algorithms, where inter-coding adopts LT (Luby Transform) codes to combat frame loss, whereas intra-coding uses RS (Reed Solomon) codes to recover corrupted frames. It chooses the optimal coding rate to decode all frames according to frame bit error rate and loss rate during transmission. When all frames are decoded, it is unnecessary to retransmit them, thus improving link throughput. We evaluate AdaCode via simulation in MATLAB using real-network trace. The simulation results show that AdaCode can improve link throughput efficiently at both fixed and variable physical-layer rate.

 

Key words: long distance, wireless mesh networks, 802.11n, RS code, LT code

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