Ultra-wideband (UWB) technology can offer very efficient solutions for various vehicular communication applications. The authors propose to use this technique to establish vehicle-to-vehicle and vehicle-to-infrastructure communications. In fact, compared to traditional carrier-based technology, UWB is a carrierless system that implements new paradigms in terms of signal generation and reception. Thus, designing a UWB communication system requires the understanding of a mechanism which allows us to have wide bandwidth and very low transmitted powers used jointly to provide a reliable radio link. UWB offers potential transceiver systems with very simple implementations. Two approaches have emerged, which meet all the communication requirements: impulse and multi-band systems. The present work relies on the first approach. So, the authors propose to use orthogonal functions called modified Gegenbauer functions (MGF) in the UWB system. Different scenarios are studied and compared in the scope of a system offering communication for subway trains. The authors propose a new receiver for the MGF-UWB communication system. To evaluate the performances of the proposed communication system, the bit error rate values are calculated and analysed in the presence of multi-user interference, considering synchronous and asynchronous cases. This study shows that this new receiver offers the required performance, for our UWB communication in transport systems, better than the performance obtained using a conventional receiver.

In hierarchical mobile IPv6 (HMIPv6), mobility anchor points (MAPs) are introduced to reduce the signalling cost by localising the signalling traffic of mobile nodes (MNs). However, the presence of MAPs introduces areas of bottleneck within the network. This study evaluates the impact of overlapped domains of consecutive MAPs in HMIPv6 access networks. In this novel network architecture, an MAP registration algorithm is also proposed to enable MNs to register with more than one MAP simultaneously. For each flow, the proposed algorithm determines a primary and a secondary MAP according to the quality of service (QoS) requirements of the traffic flow. Load balancing is also introduced to provide an even distribution of load among MAPs. In addition, an extended router advertisement is proposed to enable multiple MAP registration of MNs. The impact of the proposed algorithm in the new HMIPv6 network architectures is compared with a non-QoS aware multi-MAP registration algorithm in access network with no overlapped MAP domains. The simulation-based comparison study illustrates a maximum of 71 and 74% improvements in total amount of rejected bandwidth and the mean satisfied flow requests in network, respectively.

In this study, the authors propose a cluster-based trust management model that efficiently detects the malicious nodes and restricts them to be on a route in wireless ad hoc networks. In contrast to previous works, the trust of a node is calculated using various trust attributes having substantial effect on reliable routing in the networks. In the proposed model, each node periodically predicts the value of each trust attribute about other nodes using autoregression. Subsequently, the direct trust is estimated using the weighted combination of trust attributes and it is fine tuned using proportional–integral model. All these recommendation trusts, from common neighbours, are collected and combined by the clusterhead to quantify the trust, and hence the routing is reliable and secure in the proposed model. Simulation results show that the proposed trust model provides better throughput and packet delivery ratio in presence of malicious nodes compared to other existing schemes.

In this study, the authors present an analytical model for the contention-based access periods (CBAPs) and service periods (SPs) as specified in the medium access control (MAC) layer of IEEE 802.11ad standards. The analytical model for CBAP is based on a two-dimensional Markov chain which captures the hybrid nature of IEEE 802.11ad MAC. The Markov chain is used to obtain important metrics like MAC throughput and average frame service time. The SPs are modelled as a M/G/1 queueing system with vacations. Using this model, the delay experienced by packets is calculated. The accuracy of the analytical models is established by extensive simulation results. A brief insight into optimal allocation of SP and CBAP is also discussed.

Vehicular communication is an important and emerging area of research in the field of vehicular technology. The development of software and hardware in communication systems leads to the generation of new networks. Many researches and projects have been conducted in this upcoming area. Many government projects have been implemented in the USA, Japan and the European Union. The main objective of using this new technology is to create an accident free environment. New architectures, protocols and implementations of vehicular ad-hoc network (VANET) have been made in recent years to provide Intelligent Transportation Services. In this study, the authors survey the current issues like development, deployment, security challenges and about the current projects running in different countries. They also survey the mobility models and simulators required to implement VANET. They have also reviewed the emerging applications of VANET which provides services to the end users. At last, they have presented future research problems in VANET. The main motive of this survey is to explore the current ideas in vehicular communication.

The authors apply the preemptive priority queueing analysis to cognitive radio networks. Using the proposed analytical model, the authors can quantify the delay, throughput and spectrum occupancy of cognitive radio networks. Cognitive users’ packet arrivals form a retrial queue with a proper choice of the retrial rate. The authors illustrate numerical results of the delay, throughput and spectrum occupancy with respect to retrial rate, spectrum sensing time and primary user's busy rate.

In Mission-Oriented Opportunistic Networks (MOONs), the human users, who possess the mobile devices, also participate as part of the network. In this study, the authors study an aspect of human–network interplay in MOONs, by considering the effects of human emotions on the network operations. This study differs from the related existing works, which focus on detecting emotions of the users based on their activities, for example, their smart phone usage patterns. The study uses Meftah's computational model of the emotions, which itself is based on Plutchik's model. The authors model the current emotion of any user as a function of the individual's previous state of emotion and the content of the messages received by them. Specifically, the authors consider how the variation in individual emotions affect the traffic generation rate in the network. Further, they model the scenarios in which the users switch off their devices’ radios, and their effects on the message delivery ratio. The results of performance evaluation show that the delivery ratio of the messages tends to zero because of increased traffic load and inactivity of the devices’ radios, which, in turn, calls for efficient traffic management and forwarding schemes.

RSA-based secure routing protocols are computationally expensive because of the use of large public keys and/or signatures that are disadvantageous for mobile ad-hoc networks. In this study, the authors proposed a secure dynamic routing protocol, named SDRP, which uses identity-based scheme with pairing on elliptic curve. It makes use of signature and ‘Message Authentication Code’ algorithms to provide end-to-end, hop-to-hop and whole-route authentications. The proposed SDRP has several advantages over the existing RSA-based secure routing solutions. Firstly, it requires fewer signature generations and verifications on a route. Secondly, the SDRP makes use of an identity-based scheme which is certificate-less, thus saving routing overhead (RO) and storage. Finally, it uses a hardware address to generate its small size of public key. Both the qualitative analysis and the simulation results show that the proposed SDRP provides secure routes and better packet delivery fraction and with significantly less RO and latency compared with previous RSA-based secure routing protocols.