DeSSR: a Decentralized, Broadcast-Based Scalable Scheduling Reservation Protocol for 6TiSCH Networks

The emergence of IPv6 (Internet Protocol Version 6) for low-power wireless communication is considered a breakthrough allowing a densely populated multi-hop network of Internet of Things (IoT) devices to be used for data gathering over a range of 1-2 kilometer (km). However, the communication between the devices has suffered from external interferences and multi-path fading challenge. The Internet Engineering Task Force (IETF) and Institute of Electrical and Electronics Engineers (IEEE) jointly proposed The IPv6 over IEEE 802.15.4 TSCH mode (6TiSCH) to deal with existing challenges and improve network performance to meet key requirements of industrial applications. The 6Top layer integrates TSCH (Time Slotted Channel Hopping)-MAC over IEEE 802.15.4 with the rest of the IPv6 stack where the schedule allocation is performed by scheduling function (SF). However, network scalability remains an open challenge. Specifically, the 6TiSCH Working Group (WG) do not define rules towards optimal schedule allocation over Time Slotted Channel Hopping (TSCH) mode of IEEE 802.15.4. In this paper, we propose Decentralized, and Broadcast-based Scalable Scheduling Reservation Protocol for 6TiSCH Networks (DeSSR). The experimental performance analysis demonstrates strong performance under steady and bursty traffic when compared with current SFs. This makes DeSSR a strong proposal contributing towards improving scalability in large-scale 6TiSCH networks.Output Status: Forthcoming/Available Onlin

Analysis and Improvement of the On-The-Fly Bandwidth Reservation Algorithm for 6TiSCH

The IETF 6TiSCH Working Group (WG) is currently standardizing a novel architecture to integrate IEEE 802.15.4e TSCH Wireless Networks into the Internet of Things. Within the proposed 6TiSCH architecture, a Scheduling Function (SF) is used to manage the allocation of communication resources (i.e., TSCH timeslots). Although many SFs have been proposed in literature, the 6 TiSCH WG is considering the On-The-Fly (OTF) Bandwidth Reservation Algorithm as the reference SF. In this paper, we carry out an extensive simulation analysis of OTF to evaluate if, in its current definition, it can ensure the low latency and high reliability requirements of critical applications targeted by TSCH. Specifically, we investigate how its performance is affected by the RPL protocol and the 6top protocol used for routing and distributed resource negotiation, respectively. Our results show that the OTF performance is significantly affected by (i) frequent changes in the preferred parent selected by RPL, and (ii) failures in resource negotiation. These events typically lead to congestion, from which the network can hardly recover. To overcome such limitations, we propose a modified version of the Bandwidth Reservation Algorithm, named Enhanced-OTF. We show that proposed modifications can effectively improve the overall network performance by allowing network nodes to recover from congestion in a short time