Abstract
With the ever-growing interests in applying wireless technologies for networked embedded systems to serve as the communication fabric, many real-time wireless technologies have been recently developed to support time-critical sensing and control applications. We proposed in previous work the RT-WiFi protocol that provides real-time high-speed predictable data delivery and enables designs to meet time-critical industrial needs. However, without explicit reliability enforcement mechanisms, our previous RT-WiFi design is either subject to uncontrolled packet loss due to noise and other interferences or may suffer from inefficient communication channel usage. In this article, we explicitly consider interference from both Wi-Fi and non-Wi-Fi based interference sources and propose two sets of effective solutions for reliable data transmissions in RT-WiFi-based networked embedded systems. To improve reliability against general non-Wi-Fi based interference, based on rate adaptation and retransmission techniques, we present an optimal real-time rate adaption algorithm together with a communication link scheduler that has low network management overhead. A novel technique called overbooking is introduced to further improve the schedulability of the communication link scheduler while maintaining the required communication reliability. For Wi-Fi-based interference, we present mechanisms that utilize virtual carrier sensing to provide reliable data transmission while co-existing with regular Wi-Fi networks. We have implemented the proposed algorithms in the RT-WiFi network management framework and demonstrated the system performance with a series of experiments.
- Yang Cai and M. C. Kong. 1996. Nonpreemptive scheduling of periodic tasks in uni- and multiprocessor systems. Algorithmica 15, 6 (1996), 572--599. Google Scholar
Digital Library
- O. Chipara, C. Wu, C. Lu, and W. Griswold. 2011. Interference-aware real-time flow scheduling for wireless sensor networks. In Proceedings of the Euromicro Conference on Real-Time Systems (ECRTS’11). 67--77. Google Scholar
Digital Library
- R. Costa, P. Portugal, R. Moraes, and F. Vasques. 2012. An admission control mechanism to handle real-time traffic in IEEE 802.11 networks in open communication environments. In Proceedings of the 2012 9th IEEE International Workshop on Factory Communication Systems (WFCS’12). 63--66.Google Scholar
- Friedrich Eisenbrand, Nicolai Hähnle, Martin Niemeier, Martin Skutella, José Verschae, and Andreas Wiese. 2010. Scheduling periodic tasks in a hard real-time environment. In Proceedings of the 37th International Colloquium on Automata, Languages and Programming (ICALP’10). 299--311. Google Scholar
Digital Library
- C. Ekelin. 2006. Clairvoyant non-preemptive EDF scheduling. In Proceedings of the 18th Euromicro Conference on Real-Time Systems (ECRTS’06). 7--32. Google Scholar
Digital Library
- M. R. Garey and D. S. Johnson. 1979. Computers and Intractability: A Guide to the Theory of NP-Completeness. W. H. Freeman. Google Scholar
Digital Library
- S. Han, A. K. Mok, J. Meng, Y.-H. Wei, P.-C. Huang, Q. Leng, X. Zhu, L. Sentis, K. S. Kim, and R. Miikkulainen. 2013. Architecture of a cyberphysical avatar. In Proceedings of the International Conference on Cyber-Physical Systems (ICCPS’13). Google Scholar
Digital Library
- S. Han, X. Zhu, D. Chen, A. K. Mok, and M. Nixon. 2011. Reliable and real-time communication in industrial wireless mesh networks. In Proceedings of the IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS’11). 3--12. Google Scholar
Digital Library
- I. H. Hou, V. Borkar, and P. R. Kumar. 2009. A theory of QoS for wireless. In Proceedings of the IEEE Conference on Computer Communications (INFOCOM’09). 486--494.Google Scholar
- I. H. Hou and P. R. Kumar. 2010. Scheduling heterogeneous real-time traffic over fading wireless channels. In Proceedings of the IEEE Conference on Computer Communications (INFOCOM’10). 1--9. Google Scholar
Digital Library
- IEEE 802.11 working group. 2012. IEEE 802.11 Standard. Retrieved Feburary 26, 2017 from http://www.ieee802.org/11/.Google Scholar
- K. Jeffay, D. F. Stanat, and C. U. Martel. 1991. On non-preemptive scheduling of period and sporadic tasks. In Proceedings of the IEEE Real-Time Systems Symposium (RTSS’91). 129--139.Google Scholar
- Glenn Judd, Xiaohui Wang, and Peter Steenkiste. 2008. Efficient channel-aware rate adaptation in dynamic environments. In Proceedings of the 6th International Conference on Mobile Systems, Applications, and Services (MobiSys’08). 118--131. Google Scholar
Digital Library
- Edward Lee and others. 2008. Cyber physical systems: Design challenges. In Proceedings of the 2008 11th IEEE International Symposium on Object Oriented Real-Time Distributed Computing (ISORC’08). IEEE, 363--369. Google Scholar
Digital Library
- Q. Leng, Y.-H. Wei, S. Han, A. K. Mok, W. Zhang, and M. Tomizuka. 2014. Improving control performance by minimizing jitter in RT-WiFi networks. In Proceedings of the IEEE Real-Time Systems Symposium (RTSS’14). 63--73.Google Scholar
- B. Li, Z. Sun, K. Mechitov, G. Hackmann, C. Lu, S. J. Dyke, G. Agha, and B. F. Spencer. 2013. Realistic case studies of wireless structural control. In Proceedings of the IEEE/ACM International Conference on Cyber-Physical Systems (ICCPS’13). Google Scholar
Digital Library
- C. Y. Li, C. Peng, S. Lu, X. Wang, and R. Chandra. 2015. Latency-aware rate adaptation in 802.11n home networks. In Proceedings of the IEEE Conference on Computer Communications (INFOCOM’15). 1293--1301.Google Scholar
- Linux wireless group. 2016. Minstrel. Retrieved Feburary 26, 2017 from https://wireless.wiki.kernel.org/en/developers/documentation/mac80211/ratecontrol/minstrel.Google Scholar
- M. Marouf and Y. Sorel. 2011. Scheduling non-preemptive hard real-time tasks with strict periods. In Proceedings of the 2011 IEEE 16th Conference on Emerging Technologies 8 Factory Automation (ETFA’11). 1--8.Google Scholar
- M. Nasri and G. Fohler. 2015. An efficient method for assigning harmonic periods to hard real-time tasks with period ranges. In Proceedings of the 2015 27th Euromicro Conference on Real-Time Systems. 149--159. Google Scholar
Digital Library
- Mitra Nasri and Mehdi Kargahi. 2014. Precautious-RM: A predictable non-preemptive scheduling algorithm for harmonic tasks. Real-Time Syst. 50, 4 (2014), 548--584. Google Scholar
Digital Library
- Ragunathan (Raj) Rajkumar, Insup Lee, Lui Sha, and John Stankovic. 2010. Cyber-physical systems: The next computing revolution. In Proceedings of the 47th Design Automation Conference (DAC’10). ACM, New York, NY, 731--736. Google Scholar
Digital Library
- F. Santos, L. Almeida, P. Pedreiras, L. S. Lopes, and T. Facchinetti. 2004. An adaptive tdma protocol for soft real-time wireless communication among mobile autonomous agents. In Proceedings of the International Workshop on Architecture for Cooperative Embedded Real-Time Systems (WACERTS’04), Vol. 2004. 657--665.Google Scholar
- Souvik Sen, Naveen Santhapuri, Romit Roy Choudhury, and Srihari Nelakuditi. 2010. AccuRate: Constellation based rate estimation in wireless networks. In Proceedings of the 7th USENIX Conference on Networked Systems Design and Implementation (NSDI’10). 12--12. Google Scholar
Digital Library
- J. Song, S. Han, A. K. Mok, D. Chen, M. Lucas, M. Nixon, and W. Pratt. 2008. WirelessHART: Applying wireless technology in real-time industrial process control. In Proceedings of the IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS’08). 377--386. Google Scholar
Digital Library
- Y.-H. Wei, Q. Leng, S. Han, A. K. Mok, W. Zhang, and M. Tomizuka. 2013. RT-WiFi: Real-time high-speed communication protocol for wireless cyber-physical control applications. In Proceedings of the IEEE Real-Time Systems Symposium (RTSS’13). 140--149. Google Scholar
Digital Library
- Starsky H. Y. Wong, Hao Yang, Songwu Lu, and Vaduvur Bharghavan. 2006. Robust rate adaptation for 802.11 wireless networks. In Proceedings of the 12th Annual International Conference on Mobile Computing and Networking (MobiCom’06). 146--157. Google Scholar
Digital Library
- Wenlong Zhang, Xiuming Zhu, Song Han, Nancy Byl, Aloysius K. Mok, and Masayoshi Tomizuka. 2012. Design of a network-based mobile gait rehabilitation system. In Proceedings of the IEEE International Conference on Robotics and Biomimetics (ROBIO’12). 1773--1778.Google Scholar
Cross Ref
Index Terms
Schedule Adaptation for Ensuring Reliability in RT-WiFi-Based Networked Embedded Systems
Recommendations
A 802.11 based slotted dual-channel reservation MAC protocol for in-building multi-hop networks
In this paper, we propose a novel slotted Dual-Channel Reservation (DCR) MAC protocol that uses 802.11 primitives for providing both Quality of Service (QoS) and fairness. RTS/CTS handshaking is transmitted on a separated control channel to prevent ...
Enhanced statistics-based rate adaptation for 802.11 wireless networks
Rate adaptation is a common technique to exploit channel diversity in wireless networks. Despite the many rate adaptation algorithms proposed for 802.11 networks, statistics-based schemes remain the most widely adopted approaches in commercial 802.11 ...
A real-time services performance and interference mitigation for femtocell scenarios in LTE networks
LCN '12: Proceedings of the 2012 IEEE 37th Conference on Local Computer Networks (LCN 2012)In order to enhance the Quality of Service in LTE, femtocell architecture has been proposed as a promising solution. However, interference is the main weak point in femtocell scenarios which causes a serious impact on multimedia services performance. ...






Comments