Alexandros Ladas

Towards a scalable routing approach for Mobile Ad-hoc Networks

The Internet is evolving towards a two-fold architecture that will comprise of traditional infrastructure based networks as well as emerging self organised autonomic peripheral networks. Such Internet peripheral networks are being termed as the Internet of things (IoT) whereby smart objects and devices will be connected together in a fully distributed fashion to provide ubiquitous services through pervasive networking. Mobile Ad hoc Networks (MANETs) is regarded as one of the pervasive self-organised networks that will play a major role in autonomic future internet communication. There are several wellknown challenges to be addressed in order to enable MANET deployments of large islands of interconnected smart devices. Therefore, in this paper, we perform simulations using the ns-2 software, for various well-known routing protocols for MANETs in order to determine the scalability of these protocols. This paper analyses the scalability of the routing protocols with respect to routing overhead required by approaches while also considering the packet delivery latency, which is an important Quality of Service (QoS) metric.

Multipath routing approach to enhance resiliency and scalability in ad-hoc networks

This paper presents Multipath-ChaMeLeon (MCML) as an update of the existing ChaMeLeon (CML) routing protocol. CML is a hybrid and adaptive protocol designed for Mobile Ad-Hoc Networks (MANETs), supporting emergency communications. M-CML adopts the attributes of the proactive Optimized Link State Protocol (OLSR) and extends it so as to implement a multipath routing approach based on the Expected Transmission Count (ETX). The paper substantiates the efficiency of the protocol through a simulation scenario within a MANET using the NS-3 simulator. The acquired results indicate that M-CML routing approach combined with an intelligent link metric such as the ETX reduces the effects of link instabilities and enhances the network performance in terms of resiliency and scalability.

A selective multipath routing protocol for ubiquitous networks

Abstract During the past years, ubiquitous networks have become an interesting topic for research due to their flexible and independent nature in terms of network infrastructure. A lot of effort has been made around the design of efficient routing protocols, mainly because of their unique characteristics, such as, dynamic topology, high mobility and limited bandwidth. In this paper, we propose a new routing protocol which is based on our Multipath-ChaMeLeon (M-CML) routing protocol. We perform a network optimization analysis of M-CML under a series of simulations taking into account three Quality of Service (QoS) metrics and we provide the results with statistical confidence interval by applying the Wilcoxon signed-rank test model. On top of the outcome of the analysis, we also apply an intelligent algorithm to enhance our protocol’s effectiveness by reducing the improvident emission of data packets. The new protocol, named M-CMLv2, is compared to OLSR, AOMDV and M-CML using the NS-3 simulator. The acquired results indicate that M-CMLv2 reduces the redundant information, maintains good performance at successfully delivering packets with acceptable end-to-end delay, while at the same time, it reduces the network’s routing load and the energy consumption of the nodes.

Next-generation communication systems for PPDR: the SALUS perspective

Abstract Public Protection and Disaster Relief (PPDR) agencies in European member states currently rely on digital Private Mobile Radio (PMR) networks for mission critical operations. PMR networks are based on two main standards for Europe: Terrestrial Trunked Radio (TETRA) and TETRAPOL. These networks provide secure and resilient mobile voice services, as well as basic data services. However, these traditional PMR networks show substantial limitations, when matched against modern requirements of PPDR agencies, including broadcast communications, dynamic secure groups, secure roaming, and emerging safety and security applications. Moreover, there are significant interoperability constraints when using multiple technologies, such as inter-technology coverage limitations, which can result in ineffective management of emergency events, both at national level as well as in cross-border regions.

A multipath mobile ad-hoc routing protocol for enhanced reliability in lossy communications

Reliability of communication in unpredictable environments with increased complexity and lossless properties is one of the main objectives in wireless communication technologies. The autonomous nature of Mobile Ad hoc Networks (MANETs) classifies them as an effective solution to address emergency situation scenarios, such as rescue or disaster relief operations that take place in hostile and hazardous environments. This paper proposes a multipath approach based on the proactive Optimized Link State Routing (OLSR) protocol called RESCUE OLSR (R-OLSR), designed as an initial approach of the EU-ICT RESCUE project. The protocol exploits its capability to identify and transmit data via multiple paths based on two different relay approaches named Simple Relay Routing (SRR) and Advanced Relay Routing (ARR). The protocols efficiency is substantiated through a simulation scenario within a MANET using the NS-3 simulator. The acquired results indicate that a partial flooding of data increases the probability of receiving correct packets, improving the transmission reliability and routing performance.

Secure and interoperable communication infrastructures for PPDR organisations

The growing number of events affecting public safety and security (PS&S) on a regional scale with potential to grow up to large scale cross border disasters puts an increased pressure on agencies and organisation responsible for PS&S. In order to respond timely and in an adequate manner to such events, Public Protection and Disaster Relief (PPDR) organisations need to cooperate, align their procedures and activities, share the needed information and be interoperable. Existing PPDR/PMR technologies such as TETRA, TETRAPOL or P25, do not currently provide broadband capability nor is expected such technologies to be upgraded in the future. This presents a major limitation in supporting new services and information flows. Furthermore, there is no known standard that addresses interoperability of these technologies. In this contribution the design of a next generation communication infrastructure for PPDR organisations which fulfills the requirements of secure and seamless end-to-end communication and interoperable information exchange within the deployed communication networks is presented. Based on Enterprise Architecture of PPDR organisations, a next generation PPDR network that is backward compatible with legacy communication technologies is designed and implemented, capable of providing security, privacy, seamless mobility, QoS and reliability support for mission-critical Private Mobile Radio (PMR) voice and broadband data services. The designed solution provides a robust, reliable, and secure mobile broadband communications system for a wide variety of PMR applications and services on PPDR broadband networks, including the ability of inter-system, interagency and cross-border operations with emphasis on interoperability between users in PMR and LTE.

Securing Neighbourhood Discovery for Mobile Ad-Hoc Networks

We propose the use of a secure topology discovery scheme, based on certificate-less public key management, as part of a proposed secure version of the Neighbourhood Discovery Protocol (NHDP) for Mobile Ad-Hoc Networks. We provide an initial evaluation of the computational cost of sending secure HELLO messages, based on an Android app deployed within a small test-bed environment.