Asim Rasheed

VANET architectures and protocol stacks: a survey

Intelligent transportation systems (ITS) provide a set of standards for vehicular communications. The main focus of research activities, within ITS, has been on development of safety, traffic efficiency and infotainment related applications. Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communications are the main research goals of ITS. This paper reviews some popular architectures of VANETs (Vehicular Ad hoc NETworks) i.e., WAVE by IEEE, CALIM by ISO, C2CNet by C2C consortium / GeoNet. It also includes some recent research regarding these standards, specially focusing on Network and MAC layer issues. This paper also discusses safety related application protocols, i.e. WSMP by WAVE, CALM FAST by ISO and C2CNet by C2C consortium. Various recommendations regarding the above protocol stacks are presented. The recommendations are based on different parameters like flexibility, implementation etc.

Protocol Independent Adaptive Route Update for VANET

High relative node velocity and high active node density have presented challenges to existing routing approaches within highly scaled ad hoc wireless networks, such as Vehicular Ad hoc Networks (VANET). Efficient routing requires finding optimum route with minimum delay, updating it on availability of a better one, and repairing it on link breakages. Current routing protocols are generally focused on finding and maintaining an efficient route, with very less emphasis on route update. Adaptive route update usually becomes impractical for dense networks due to large routing overheads. This paper presents an adaptive route update approach which can provide solution for any baseline routing protocol. The proposed adaptation eliminates the classification of reactive and proactive by categorizing them as logical conditions to find and update the route.

‘3D’-a Doppler, Directivity and Distance based architecture for selecting stable routing links in VANETs

Vehicular networks show very fast topology changes and frequent network fragmentation. Selection of stable routing links in multi-hop communication requires the speed and direction of movement of the neighbouring vehicles to be taken into account. This paper proposes‘3D’: a Doppler, Distance and Directivity based routing protocol architecture, making decisions on considerations of relative vehicular speed and direction. From amongst the stable links, to select those having longest lifetime, distance between the nodes and their relative placement is considered.

Vehicular Ad Hoc Network (VANET): A Survey, Challenges, and Applications

An ad hoc network consisting of vehicles has emerged as an interesting but challenging domain where a lot of new application may find their place. Though research in this field is on since last two decades, large-scale practical implementation still require some time. In this paper, a survey of current challenges and potential applications, incorporating medium access control schemes, routing approaches, hardware and spectrum issues, and security and privacy issues for VANETs, is presented.

Security architecture parameters in VANETs

Vehicular area networks are prone to very fast topology changes and require support for multiple types of services. This leads to a requirement of strict guarantees for quality of services (QoS). Many real time or partial real time applications are bound to share the user information which may hurt privacy of the user. In critical scenarios where quick decision making is of high importance, users may not be able to adhere to standard cryptographic procedures, and this may lead to false decisions. This paper compares different options available for cryptographic procedures and proposes a mechanism for swift decision making based on regional and application based certificates.

An intelligent hybrid spread spectrum MAC for interference management in mobile ad hoc networks

This paper presents and analyses a fully distributive intelligent hybrid spread spectrum MAC for ad hoc networks. The IHSS MAC scheme has been developed with the aim to mitigate far field interference with the use of a robust DSSS physical layer, while managing near field interference with the use of intelligent slow frequency hopping. The IHSS design ensures a minimum required SINR threshold at active receivers, under low outage probability constraints. IHSS does not inhibit any nodes in space neither thins them out in time. A lower bound on transmission capacity for the case where the size of the frequency hopping zone is variable is derived in this paper. The mathematical model is validated through simulation. The simulation is based on a hopping sequence selection methodology that randomizes the available hopping sequences within a frequency hopping zone around each active receiver. The implementation utilises the RTS/CTS concept of the CSMA MAC, with a slight modification. The performance criterion used for analysis is transmission capacity normalized by the required bandwidth. It is observed that implementation of a suitable sized frequency hopping zone using the proposed IHSS MAC, shows superior performance over ALOHA and guard zone based MACs.

An intelligent hybrid spread spectrum MAC protocol for increasing the transmission capacity of wireless ad-hoc networks

Unmanaged interference is a threat to reliable communication in ad hoc networks. Currently, ad hoc networks suppress or inhibit interferers around an active receiver to meet a minimum required signal-to-interference-plus-noise ratio threshold. Techniques like carrier sensing, random back-offs, spread spectrum, guard zone based inhibition, etc. are being used for interference management. We have developed a MAC protocol that works on the principle of not inhibiting any interferer near an active receiver. The proposed scheme uses Direct Sequence Spread Spectrum network-wide and intelligent Frequency Hopping within a zone around the receiver. Mathematical model based on stochastic geometry is validated through simulation. It is observed that proposed MAC protocol shows performance improvement over other MACs, in terms of Transmission Capacity normalized by the used spectrum.

Need justification for adaptive route update in wireless ad hoc networks

Recent advances in communications made it possible to consider wireless networks for connectivity at highly scalable rates. Efficiency of any wireless network heavily depends on efficient MAC and Routing techniques. Routing techniques, ideally, target finding suitable routes, updating and maintaining them. Most of the current research is focused on finding and maintaining efficient route, with little emphasis on route update. Our research shows that current route update techniques may not provide efficient results for the networks with high relative mobility and high active node density with frequent topological changes. We have studied different factors for adaptation of generic routing strategy. The factors computed on runtime can enhance the efficiency of existing & future routing protocols.

Smart video packet trimming technique over congested networks

In past few years, multimedia traffic is growing and Internet have maximum portion of multimedia traffic. This traffic trend is expected to increase due to multimedia applications. Best effort Internet architecture poses design limitations for multimedia traffic. IPTV like applications require higher bandwidth, low packet loss, low delays and jitter effects to transmit high quality video contents. Packet loss due to limited band width and congestion can negatively impact on Quality of Experience(QoE). Packet trimming based innovative scheme is proposed in this article to deal packet loss and improve QoE. Proposed scheme eliminate the chance of packet loss during congestion. Packet trimming scheme better handle congestion which improve video smoothness, interactivity and frame quality. Test-bed implementation and subsequent analyses shows promising improvement in video Quality of Experience over same Quality of Service.

Traffic information, management a emergency response service (TIMERs)

Road accidents is one of the leading cause of unnatural deaths. Other than human casualties, billions of dollars are being wasted every day due to traffic mismanagement. Efficient road management is the leading goal for VANET. This paper proposes a system for providing information, management and emergency response services for vehicular systems and networks. The proposed idea relies on installation of a pre-programmed chip in each vehicle at the time of registration. Existing cellular data services or dedicated VANET network interfaces can be used for cost reduction and large scale availability. For precise location finding, GPS can also be used as an additional tool in case of major emergency event such as accidents etc. The service will be used for traffic management & planning, as well as normal communication services like voice, data and SMS service among the users sitting in vehicles. The proposed design incorporates EDGE/3G/4G for data communication and is designed to cater amalgamation of next generation data networks based on future technologies. Resources used in proposed system are not only cost effective but are generally available with wide scale deployment.