D-SLATS: Distributed Simultaneous Localization and Time Synchronization

Through the last decade, we have witnessed a surge of Internet of Things (IoT) devices, and with that a greater need to choreograph their actions across both time and space. Although these two problems, namely time synchronization and localization, share many aspects in common, they are traditionally treated separately or combined on centralized approaches that results in an ineffcient use of resources, or in solutions that are not scalable in terms of the number of IoT devices. Therefore, we propose D-SLATS, a framework comprised of three different and independent algorithms to jointly solve time synchronization and localization problems in a distributed fashion. The First two algorithms are based mainly on the distributed Extended Kalman Filter (EKF) whereas the third one uses optimization techniques. No fusion center is required, and the devices only communicate with their neighbors. The proposed methods are evaluated on custom Ultra-Wideband communication Testbed and a quadrotor, representing a network of both static and mobile nodes. Our algorithms achieve up to three microseconds time synchronization accuracy and 30 cm localization error

Capacity and delay scaling for broadcast transmission in highly mobile wireless networks

We study broadcast capacity and minimum delay scaling laws for highly mobile wireless networks, in which each node has to disseminate or broadcast packets to all other nodes in the network. In particular, we consider a cell partitioned network under the simplifed independent and identically distributed (IID) mobility model, in which each node chooses a new cell at random every time slot. We derive scaling laws for broadcast capacity and minimum delay as a function of the cell size. We propose a simple first-come-firstserve (FCFS) flooding scheme that nearly achieves both capacity and minimum delay scaling. Our results show that high mobility does not improve broadcast capacity, and that both capacity and delay improve with increasing cell sizes. In contrast to what has been speculated in the literature we show that there is (nearly) no tradeoff between capacity and delay. Our analysis makes use of the theory of Markov Evolving Graphs (MEGs) and develops two new bounds on ooding time in MEGs by relaxing the previously required expander property assumption. Keywords: Mobile ad hoc networks, Wireless networks, Broadcast, Throughputdelay tradeoff, Scaling laws, Flooding time, Markov evolving graphNational Science Foundation (U.S.) (Grant CNS-1217048)National Science Foundation (U.S.) (Grant CNS-1713725)National Science Foundation (U.S.) (Grant AST-1547331

Security Enhanced Location-aided Level-based Disjoint Multipath Routing Algorithm for Mobile Ad Hoc Networks

In mobile ad hoc networks (MANET), the location-based multipath routing protocols involves less routing overhead compared to non-location-based protocols. This paper proposes two location-based algorithms, Enhanced Location-aided Level-based node Disjoint Multipath routing (ELLDMR) and Secure Location-aided Level-based node Disjoint Multipath routing (SLLDMR), to enhance the link lifetime and the security of the MANET. The objective of ELLDMR is to build multiple paths with non-critical nodes so that the lifetime of the routing path is significantly increased. It also hides the source, destination and path identity in intermediate nodes to avoid intrusion of routing attacks in the routing path. The SLLDMR is an enhancement over ELLDMR where it aims to overcome rushing attack and exhibit secure data transmission using two-level cryptographic processes. The performances of ELLDMR and SLLDMR are simulated using NS2 where it shows a minimum routing overhead, less end to end delay and high packet delivery compared to existing Location-aided Level-based node Disjoint Multipath routing (LLDMR) algorithm and Topology Hiding multipath protocol (TOHIP)

Effective Handover Technique in Cluster Based MANET Using Cooperative Communication

Mobile ad hoc networks (MANETs) are becoming increasingly common now a days and typical network loads considered for MANETs are increasing as applications evolve. This increases the importance of bandwidth efficiency and requirements on energy consumption delay and jitter. Coordinated channel access protocols have been shown to be well suited for MANETs under uniform load distributions. However, these protocols are not well suited for non-uniform load distributions as uncoordinated channel access protocols due to the lack of on-demand dynamic channel allocation mechanisms that exist in infrastructure based coordinated protocols. We have considered a lightweight dynamic channel allocation algorithm and a cooperative load balancing strategy that are helpful for the cluster based MANETs and an effective handover technique to improve the increased packet transmission mechanism. This helps in reduce jitter, packet delay and packet transfer speed, we use a novel handover algorithm to address this problem We present protocols that utilize these mechanisms to improve performance in terms of throughput, energy consumption and inter-packet delay variation (IPDV)

A survey on Bluetooth multi-hop networks

Bluetooth was firstly announced in 1998. Originally designed as cable replacement connecting devices in a point-to-point fashion its high penetration arouses interest in its ad-hoc networking potential. This ad-hoc networking potential of Bluetooth is advertised for years - but until recently no actual products were available and less than a handful of real Bluetooth multi-hop network deployments were reported. The turnaround was triggered by the release of the Bluetooth Low Energy Mesh Profile which is unquestionable a great achievement but not well suited for all use cases of multi-hop networks. This paper surveys the tremendous work done on Bluetooth multi-hop networks during the last 20 years. All aspects are discussed with demands for a real world Bluetooth multi-hop operation in mind. Relationships and side effects of different topics for a real world implementation are explained. This unique focus distinguishes this survey from existing ones. Furthermore, to the best of the authors’ knowledge this is the first survey consolidating the work on Bluetooth multi-hop networks for classic Bluetooth technology as well as for Bluetooth Low Energy. Another individual characteristic of this survey is a synopsis of real world Bluetooth multi-hop network deployment efforts. In fact, there are only four reports of a successful establishment of a Bluetooth multi-hop network with more than 30 nodes and only one of them was integrated in a real world application - namely a photovoltaic power plant. © 2019 The Author

NOVA mobility assistive system: Developed and remotely controlled with IOPT-tools

UID/EEA/00066/2020In this paper, a Mobility Assistive System (NOVA-MAS) and a model-driven development approach are proposed to support the acquisition and analysis of data, infrastructures control, and dissemination of information along public roads. A literature review showed that the work related to mobility assistance of pedestrians in wheelchairs has a gap in ensuring their safety on road. The problem is that pedestrians in wheelchairs and scooters often do not enjoy adequate and safe lanes for their circulation on public roads, having to travel sometimes side by side with vehicles and cars moving at high speed. With NOVA-MAS, city infrastructures can obtain information regarding the environment and provide it to their users/vehicles, increasing road safety in an inclusive way, contributing to the decrease of the accidents of pedestrians in wheelchairs. NOVA-MAS not only supports information dissemination, but also data acquisition from sensors and infrastructures control, such as traffic light signs. For that, it proposed a development approach that supports the acquisition of data from the environment and its control while using a tool framework, named IOPT-Tools (Input-Output Place-Transition Tools). IOPT-Tools support controllers’ specification, validation, and implementation, with remote operation capabilities. The infrastructures’ controllers are specified through IOPT Petri net models, which are then simulated using computational tools and verified using state-space-based model-checking tools. In addition, an automatic code generator tool generates the C code, which supports the controllers’ implementation, avoiding manual codification errors. A set of prototypes were developed and tested to validate and conclude on the feasibility of the proposals.publishersversionpublishe