Wireless technologies are being used in various applications for their ease of deployment and inherent capabilities to support mobility. Most wireless standards supports multiple data rates that may vary between few Mbps to few Gbps. Reaching the maximum supported data rate is what most application seek for. Nevertheless, the choice of data rates is very closely related to the quality of communication links and their stability. IEEE 802.11 standard introduced multi-rate support, since then, a lot of research has been done on rate adaptation, dealing with the different parameters that lead to an estimation of the channel conditions and the metrics that affect the network performance. In this paper, we present some of the popular rate adaptation schemes and summarize their characteristics. We categorize them as well into different categories according to their design and functionalities in terms of the strategies that are used to estimate channel conditions and decision making. We implemented some algorithms from the different categories in the network simulator NS-3 in order to evaluate their performance under different scenarios in Ad hoc and infrastructure modes. We present the lessons learned as well as our insights for future research work that can enhance the current approaches in the literature.

Cooperative Intelligent Transport Systems (C-ITS) are special type of Vehicular Ad-hoc NETworks (VANETs) that aim to create networks between vehicles to increase traffic safety, mitigate traffic congestion, and enhance driving comfort. Green Light Optimal Speed Advisory (GLOSA) is one the many use-cases of C-ITS. GLOSA aims to minimize trip time and fuel consumption by providing vehicles, via a wireless channel, with specific information to calculate an advisory speed to be respected when approaching a traffic light. However, Wireless communications are prone to packet loss and delay which could considerably impact applications and user experience. In this paper, we study the impact of network performance on the efficiency of GLOSA. We compare two different strategies to find advisory speeds, one that aims at reducing trip time and the other at reducing fuel consumption and CO ₂ emission. Results show different impact of network performance on GLOSA depending on the strategy that is followed.

Wireless sensor networks are a challenging field of research when it comes to security issues. Using low cost sensor nodes with limited resources makes it difficult for cryptographic algorithms to function without impacting energy consumption and latency. In this paper, we focus on key management issues in multi-hop wireless sensor networks. These networks are easy to attack due to the open nature of the wireless medium. Intruders could try to penetrate the network, capture nodes or take control over particular nodes. In this context, it is important to revoke and renew keys that might be learned by malicious nodes. We propose several secure protocols for key revocation and key renewal based on symmetric encryption and elliptic curve cryptography. All protocols are secure, but have different security levels. Each proposed protocol is formally proven and analyzed using Scyther, an automatic verification tool for cryptographic protocols. For efficiency comparison sake, we implemented all protocols on real testbeds using TelosB motes and discussed their performances.