Sabih ur Rehman

A Synopsis of Simulation and Mobility Modeling in Vehicular Ad-hoc Networks (VANETs)

Vehicular communication is considered to be a backbone for many critical safety applications. In order to achieve a better implementation of any vehicular communication scenario, an efficient, accurate and reliable simulator is essential. Various open source and commercial simulating tools are available for this purpose. One of the key issues in this regard is the selection of a reliable simulator which implements all standard algorithms and paradigms giving accurate results. In this paper, we first present IEEE standard and protocols for vehicular communication, IEEE 802.11p and IEEE 1609.x, also known as WAVE protocol stack. The paper then discusses the necessary requirements for a generic discrete event simulator which can be used to simulate Vehicular Ad-hoc Networks. Since not all the network simulators can be used in the scenario of vehicular communication, we highlight the key features of some network simulators in the context of vehicular ad-hoc networks. The paper also highlights some of the implementation limitations in these simulators. Furthermore, the paper presents a discussion on traffic simulators by emphasizing on the underlying mobility models used in order to generate the realistic traffic patterns. A comparative study of both network and traffic simulators show the pros and cons of these simulation tools. The paper suggests the appropriate choice of a network simulator to be used as a VANET simulator.

Cross layer routing for VANETs

Routing is an important and critical issue for successful transmission in Vehicular Ad-hoc Networks (VANETs). Most of the traditionally designed routing schemes are based on optimising their parameters individually in the existing VANET architecture. Such approaches may not result in an overall efficient system. Therefore, it is important to consider various parameters from multiple layers such as PHY and MAC, to optimise routing. In this paper while presenting a new cross-layer routing scheme, we subdivide the existing OSI model in three main layers. The routing scheme presented in this paper considers parameters from multiple layers simultaneously to achieve the routing objectives. We argue that the proposed routing scheme results in less packet drops and comparatively smaller delay in packet transmission.

Wireless transmission modeling for Vehicular Ad-hoc Networks

Modeling wireless transmission in stringent networks such as VANETs is a challenging task. This requires mathematically incorporating all the environmental effects present within such a dynamics atmosphere. The key attributes to model the wireless channel are physical constraints inherent to such networks such as lack of permanent infrastructure, limited knowledge in relation to the position of vehicles as well as interference that effects the strength of receive signal at each position of vehicles. The selection of an appropriate transmission model plays a key role in the routing decisions for VANET. This paper investigates such wireless transmission models for vehicular communication. It identifies the situations where a particular model can be beneficial. The paper also provides an insight into the use of practical parameters in theoretical transmission models. An analysis of the proposed transmission model is presented. The performance of different transmission models in terms of receive signal strength (RSS) is also presented. These results help to select a transmission model that suits best to a particular VANET communication scenario.

Quality of service based cross layer routing protocol for VANETs

Achieving high Quality of Service (QoS) in routing is one of the major issues to be tackled in VANET. This is primarily due to the interference among vehicles and the objects present within the transmission environment. This also causes rapid degradation in transmitted signal and affects the overall system throughput. As a result, the system performance parameters such as delay, packet drop ratio and efficiency are highly effected. This paper proposes a Cross-Layer Decision Based (CLDB) routing protocol that necessitates to choose the best path for routing the packets to meet promised QoS requirements. The protocol considers the parameters from both PHY and MAC layers to optimise the routing objective. Performance of the proposed algorithm is evaluated using extensive computer simulations.

A multi-hop cross layer decision based routing for VANETs

Abstract In recent years, vehicular ad-hoc networks have emerged as a key wireless technology offering countless new services and applications for the transport community. Along with many interesting and useful applications, there have been a number of design challenges to create an efficient and reliable routing scheme. A conventional design approach only optimizes routing schemes without considering the constraints from other network layers. This may result in an under-performing routing mechanism. In this paper we present the design of a multi-hop cross-layer routing scheme that utilises beaconing information at the physical layer as well as queue buffer information at medium access control layer to optimise routing objectives. In particular, the proposed scheme integrates channel quality information and queuing information from other layers to transmit data. Using simulations as well as analytical studies we have presented results of our proposed scheme and have done a thorough comparison with existing approaches in this area. The results highlight better performance of the proposed cross-layer structure as compared to other conventional single layer approaches.

Optimizing Broadcasting Scheme for VANETs Using Genetic Algorithm

Broadcasting is one of the communication mechanism utilised in VANET architecture through which an up-to-date traffic data can be disseminated among the commuters and this can help reduce traffic jams/congestions. Broadcasting storm (broadcasting) is considered to be an NP-hard problem consisting of multiple objectives. Conventional techniques use Multi-Objective Genetic Algorithms (MOGAs) to solve such optimization problems. Performance of such algorithms depend on fitness function. In this paper, we propose a novel and improved fitness function for MOGA to solve the broadcasting problem in VANETs. The proposed fitness function has enhanced the rate of evolution, resulting in more generations and producing better optimization results. We consider a highway scenario for simulation to evaluate performance of the proposed solutions. We compare the results of the proposed algorithm with existing state-of-the-art technique [1]. Our results show improvement in reduction of the propagation time and the number of retransmissions compared to the previous solution.

A practical miniature antenna design for future internet of things enabled smart devices

Internet of Things (IoT) will play an important role in the contemporary communication networks. In this modern and future communication paradigm hundreds of different smart Internet enabled devices will communicate with each other continuously. For such communication networks and smart devices, apart from the sophisticated communication protocols, efficient hardware will also play a very crucial role. Antennas being at the front end of communication, are one of the important components of such a hardware. The antennas for IoT applications are required to exhibit three important characteristics, namely; (i) small size, (ii) energy efficiency and (iii) ability to operate in multi antenna environment. In this paper, we propose an antenna design that fulfils these important requirements. We propose an ultra-wideband antenna that is small in size compared to other existing designs, with dimensions 24 × 28 mm2, that can easily fit in hand-held mobile devices. Measured results indicate that the antenna not only has a very small power return loss but also exhibits a low mutual coupling that highlights that the proposed design is capable to operate in multiple-input multiple-output (MIMO) configurations.

Broadcasting under Highway Environment in VANETs Using Genetic Algorithm

Broadcasting is a part of the communication spectrum supported by VANETs through which information is disseminated to all the vehicles in the network. The dissemination process requires multiple retransmissions to achieve network coverage in a multi-hop environment. However, unsupervised retransmissions cause broadcasting storm, whereas on the other hand network coverage is cannot be achieved without retransmissions. In order to achieve network coverage without creating broadcast storm, the work in [1] proposed the modified Genetic Algorithm based on the analytic fitness function in static highway scenario. In this paper, we use the same approach of the modified GA in a dynamic highway environment. The paper introduces vehicular movement in the model under study by proposing the vehicle speed between 60 and 100 km/h. The result shows minor differences in the number of of retransmissions as well as propagation time for both static and dynamic highway scenario. This is due to the fact that the distance covered by the vehicles movement during the time period required to achieve network coverage is too small.

Low-Cost Printed Flexible Antenna by Using an Office Printer for Conformal Applications

A low-cost inkjet printing method for antenna fabrication on a polyethylene terephthalate (PET) substrate is presented in this paper. An office inkjet printer is used to have desired patterns of silver nanoparticle ink on the PET substrate without any postprocessing. Silver nanoparticle ink cures instantly as soon as it is ejected from the printer on a chemically treated PET substrate. The thickness of the silver nanoparticle layer was measured to be 300 nm with a sheet resistance of as low as 0.3 Ω/sq and a conductivity around 1.11 × 107 S/m with single layer deposition. A coplanar waveguide- (CPW-) fed Z-shape planar antenna on the PET substrate achieved the measured radiation efficiency of 62% and the IEEE gain of 1.44 dBi at 2.45 GHz. The printed antenna is also tested in bending conditions to ascertain its performance for the Internet of things (IoT) conformal applications for the future 5G network.

Exploring Secure Communication in VANET Broadcasting

Broadcasting is a communication mechanism utilized in VANET architecture that facilitates in disseminated of public information to help reduce traffic jams/congestions. The authentic and genuine nature of public information is required to be maintained to avoid broadcasting of false information causing mass panic and hysteria. Therefore, it is of utmost importance to secure the broadcasting information so that the information cannot be altered by the intruders without compromising public nature of the information. In this paper, we have proposed a secure broadcasting architecture consisting of different layers stacked together in different formation according to operating modes. A real-time simulation model is developed in Python, while simulations are run on supercomputer for the purpose of gathering results for highway environments. We compare the results of the proposed secure highway architecture with unsecure architecture. Overall, the results show delayed propagation time due to availability of multiple information packets as well as prioritization of these information packets. However, there was no significant difference in retransmission of different information packets when compared with either different broadcasting probability or unsecure highway scenario, which indicates an effective as well as efficient secure broadcasting architecture.