Control-Based Resource Management Procedures for Satellite Networks

This paper describes the resource management of a DVBRCS geostationary satellite network. The functional modules of the access layer aim at efficiently exploiting the link resources while assuring the contracted Quality of Service (QoS) to the traffic entering the satellite network. The main novelty is the integration between the Connection Admission Control and the Congestion Control procedures. Both them exploit the estimation of the traffic load, performed by a Kalman filter. The proposed solution has been analysed via computer simulations, which confirmed their effectiveness

MR-BART: Multi-Rate Available Bandwidth Estimation in Real-Time

In this paper, we propose Multi-Rate Bandwidth Available in Real Time (MR-BART) to estimate the end-to-end Available Bandwidth (AB) of a network path. The proposed scheme is an extension of the Bandwidth Available in Real Time (BART) which employs multi-rate (MR) probe packet sequences with Kalman filtering. Comparing to BART, we show that the proposed method is more robust and converges faster than that of BART and achieves a more AB accurate estimation. Furthermore, we analyze the estimation error in MR-BART and obtain analytical formula and empirical expression for the AB estimation error based on the system parameters.Comment: 12 Pages (Two columns), 14 Figures, 4 Tables

VANET Applications Under Loss Scenarios & Evolving Wireless Technology

In this work we study the impact of wireless network impairment on the performance of VANET applications such as Cooperative Adaptive Cruise Control (CACC), and other VANET applications that periodically broadcast messages. We also study the future of VANET application in light of the evolution of radio access technologies (RAT) that are used to exchange messages. Previous work in the literature proposed fallback strategies that utilizes on-board sensors to recover in case of wireless network impairment, those methods assume a fixed time headway value, and do not achieve string stability. In this work, we study the string stability of a one-vehicle look-ahead CACC platoon under different network loss scenarios, and propose to adapt the time headway parameter of the model according to a network reliability metric that we defined based on packet burst loss length to maximize traffic flow efficiency while maintaining a string stable platoon. Our findings show that careful adjustment of headway value according to the wireless network reliability allows the platoon to maintain string stable operation while maximizing traffic flow. We also study the impact that evolving wireless technology can have on VANET applications such as CACC, where we study the performance when using DSRC and 5G NR V2X. In addition, we study the evolution of RATs used in VANET application, and we propose DSRC+, as a possible enhancement to traditional DSRC, that utilizes modern modulation/coding schemes and performs random blind retransmission to improve packet delivery ratio. We finally study the trade-offs in the choice of RAT in VANET applications such as CACC, concluding that RATs with time-division channel access can be reliable with lower packet loss, but performs poorly when needing to disseminate messages over longer CACC platoons

On the Security of the Automatic Dependent Surveillance-Broadcast Protocol

Automatic dependent surveillance-broadcast (ADS-B) is the communications protocol currently being rolled out as part of next generation air transportation systems. As the heart of modern air traffic control, it will play an essential role in the protection of two billion passengers per year, besides being crucial to many other interest groups in aviation. The inherent lack of security measures in the ADS-B protocol has long been a topic in both the aviation circles and in the academic community. Due to recently published proof-of-concept attacks, the topic is becoming ever more pressing, especially with the deadline for mandatory implementation in most airspaces fast approaching. This survey first summarizes the attacks and problems that have been reported in relation to ADS-B security. Thereafter, it surveys both the theoretical and practical efforts which have been previously conducted concerning these issues, including possible countermeasures. In addition, the survey seeks to go beyond the current state of the art and gives a detailed assessment of security measures which have been developed more generally for related wireless networks such as sensor networks and vehicular ad hoc networks, including a taxonomy of all considered approaches.Comment: Survey, 22 Pages, 21 Figure