Congestion control in wireless sensor and 6LoWPAN networks: toward the Internet of Things

The Internet of Things (IoT) is the next big challenge for the research community where the IPv6 over low power wireless personal area network (6LoWPAN) protocol stack is a key part of the IoT. Recently, the IETF ROLL and 6LoWPAN working groups have developed new IP based protocols for 6LoWPAN networks to alleviate the challenges of connecting low memory, limited processing capability, and constrained power supply sensor nodes to the Internet. In 6LoWPAN networks, heavy network traffic causes congestion which significantly degrades network performance and impacts on quality of service aspects such as throughput, latency, energy consumption, reliability, and packet delivery. In this paper, we overview the protocol stack of 6LoWPAN networks and summarize a set of its protocols and standards. Also, we review and compare a number of popular congestion control mechanisms in wireless sensor networks (WSNs) and classify them into traffic control, resource control, and hybrid algorithms based on the congestion control strategy used. We present a comparative review of all existing congestion control approaches in 6LoWPAN networks. This paper highlights and discusses the differences between congestion control mechanisms for WSNs and 6LoWPAN networks as well as explaining the suitability and validity of WSN congestion control schemes for 6LoWPAN networks. Finally, this paper gives some potential directions for designing a novel congestion control protocol, which supports the IoT application requirements, in future work

MAC Layer Support for Delay Tolerant Video Transport in Disruptive MANETs

Part 3: DTN and Sensor NetworksInternational audienceThe overall goal of this work is to improve video delivery in emergency and rescue scenarios using sparse MANETs that might be prone to frequent link breaks and network partitions. The core idea of our approach is to reduce the number of MAC layer retransmissions that are likely to fail. We do not drop packets that could not be sent after the final retransmission. Instead we handle them in an overlay for store-carry-forwarding. The design of the overlay protocol takes the instability of the network into account, in such a way that each overlay entity works autonomously and keeps a minimum amount of state. Our experimental results show that we reduce packet loss seen on broken links, while at the same time significantly reducing overhead in terms of the total amount of packets transmitted at the physical layer