Nishu Gupta

Medium access control protocols for safety applications in Vehicular Ad-Hoc Network

Vehicular Ad-Hoc Network (VANET) is seen as an emerging solution to improve road safety, highway assistance and traveler comfort accounting to vivid applications including safety, non-safety and infotainment applications. Over the past few years, research paradigm has shifted towards areas such as multi-hop broadcasting, information security, clustering, etc. covering intra-vehicular and vehicle-to-infrastructure communication modes. Whereas these scenarios provide diversified information dissemination techniques through various applications of Intelligent Transportation Systems (ITS), data dissemination in VANET environment is still a challenging task, mainly due to rapid changes in network topology and frequent disruptions in connectivity. A distinguished area that still lacks significant research contributions is towards designing reliable and efficient Medium Access Control (MAC) protocols for vehicular communication in order to enhance travel safety. The main motivation behind such a survey is to integrate a wide range of research contributions that have been recently proposed to envisage the inherent characteristics of vehicular communication. Such a study serves as a reference for an in-depth research towards enhancements in the PHY/MAC layers. In this paper, we present state-of-the-art survey of the MAC protocols available for vehicular safety. We classify these protocols based on different applications and the techniques they adopt. We also review the performance metrics used for evaluating these protocols. In later sections, we qualitatively analyze the protocols based on different parameters along with related issues and the challenges they generate. We highlight the mechanisms involved, conceptual features, optimization techniques, strength and drawbacks of the available protocols as well as their applicability in future deployment. Finally, we discuss the open issues and future research directions.

Clustering based cognitive MAC protocol for channel allocation to prioritize safety message dissemination in vehicular ad-hoc network

Abstract With the rising demand for vehicular networking through wireless communication for safety as well as non-safety applications, the urge to provide efficient bandwidth utilization along with reliable data delivery is rising significantly. Apparently, various communication services and applications are falling short of radio frequencies to be assigned to them. In addition to that, the IEEE 802.11p standard to enable wireless access in vehicular communication on DSRC frequencies is known to yield insufficient spectrum for reliable exchange of information over congested channels. To address these issues, this paper presents a clustering based cognitive MAC (CCMAC) protocol which allows dynamic allocation of channels in the band adjacent to the DSRC band, known as 5.8 GHz U-NII-3/ISM band. The novelty of CCMAC lies in exploiting the free unlicensed band thereby, eliminating the concept of primary and secondary user. For this purpose, we introduce mobility aware clustering based channel allocation protocol that proactively monitors the channel sensing outcomes. Using these results, vehicles access information about spectrum availability prior to transmission. The protocol ensures immediate channel access to safety messages within DSRC band at the cost of non-safety messages which are switched to U-NII-3/ISM band when falling short of channel access in the DSRC band. This not only results in alleviating access delay but also renders efficient channel utilization. The results demonstrate the effectiveness of the CCMAC protocol in allocating real-time and scalable spectral resources, fast and efficient reception of safety messages compared to existing schemes, and in alleviating the operation of safety application based services in VANET.

Adaptive Beaconing in Mobility Aware Clustering Based MAC Protocol for Safety Message Dissemination in VANET

Majority of research contributions in wireless access in vehicular environment (WAVE)/IEEE 802.11p standard focus on life critical safety-related applications. These applications require regular status update of vehicle’s position referred to as beaconing. Periodic beaconing in vehicle to vehicle communication leads to severe network congestion in the communication channel. The condition worsens under high vehicular density where it impacts reliability and upper bound latency of safety messages. In this paper, WAVE compliant enhancement to the existing IEEE 802.11p protocol is presented which targets prioritized delivery of safety messages while simultaneously provisioning the dissemination of nonsafety messages. Proposed scheme relies on dynamic generation of beacons to mitigate channel congestion and inefficient bandwidth utilization by reducing transmission frequency of beacons. Through the use of clustering mechanism, different beaconing frequencies and different data transmission rates are assigned to prioritize vehicular mobility. Through extensive simulation results, the performance of the proposed approach is evaluated in terms of a wide range of quality of service (QoS) parameters for two different transmission ranges. Results show that the proposed protocol provides significant enhancement and stability of the clustered topology in vehicular ad hoc network over existing standard and other protocols with similar applications.

Adaptive Mobility and Range Based Clustering Dependent MAC Protocol for Vehicular Ad Hoc Networks

Clustering, especially in vehicular safety applications is an important part of intelligent transportation systems. In this paper, an adaptive mobility and range based clustering (AMRBC) based MAC protocol is proposed. The protocol aims to maintain a stable clustering and hence a communication range to maintain high stability of network. Secondly, AMRBC limits the cluster size to a level at which all the cluster members can exchange their beacons within control channel interval. AMRBC prioritizes safety messages over infotainment messages by granting immediate channel access to safety messages over infotainment messages thereby significantly reducing safety message delay. Moreover, the proposed MAC protocol fairly distributes wireless channels among vehicles and ensures that all the vehicles exchange their beacons within finite interval of time. Analytical modelling along with simulation based performance analysis demonstrate the effectiveness of the proposed protocol in terms of average cluster head time, safety message delay, throughput, reliability and packet delivery ratio.

Clustering-based enhanced safety message dissemination medium access control protocol for vehicular ad hoc network

Wireless access in vehicular environment employs the IEEE 802.11p/1609.4 standard wherein a multichannel architecture is envisioned to concurrently support both time-sensitive safety-related applications and value-added entertainment services. Although a standard now, the IEEE 802.11p protocol has known shortcomings of not being capable of providing reliable broadcast services. To address this issue, clustering-based enhanced safety message dissemination MAC protocol CESD-MAC is proposed in this paper which is an enhancement over the existing IEEE 802.11p/1609.4 protocol. CESD-MAC adopts mobility aware clustering and channel access scheduling. It rules out the concept of switching between the control channel and the service channel as implemented in the legacy standard. Simulation results are presented to verify the effectiveness of the proposed protocol and comparisons are made with the existing IEEE 802.11p MAC. The results demonstrate the superiority of CESD-MAC in terms of reduction of end-to-end delay, and increased throughput, channel utilisation and packet delivery ratio PDR.

Clustering Based Single-hop and Multi-hop Message Dissemination Evaluation Under Varying Data Rate in Vehicular Ad-hoc Network

Enhancement in the existing vehicular communication technologies is important not only for efficient utilization of the available bandwidth but also for event-driven safety message dissemination in Vehicular Ad-hoc Network (VANET). Some of its unique characteristics like geographically constrained topology, unpredictable vehicle density, varying channel capacity etc. constitute VANET as a distinct research field. In this paper we compare and evaluate the performance of clustering based single-hop and multi-hop network for varying data transfer rates in the IEEE 802.11p standard by means of simulations using NS-2. Simulations are performed for highway scenario in vehicle-to-vehicle mode. Results are presented for various Quality of Service parameters such as throughput, packet delivery ratio and end-to-end delay. Significant observations have been made which would serve as an input to enhance further research in this field.

Mobility dependent clustering-based data transmission under variable data rate for different node densities in vehicular ad hoc network

Vehicular environments impose stringent requirements on the communication channels due to their inherent feature of being geographically constrained, unpredictable vehicular density, varying channel capacity and highly dynamic in nature. Enhancement in the existing vehicular communication technologies is important not only for efficient utilisation of the available bandwidth but also for event-driven safety message dissemination in vehicular ad hoc network (VANET). From safety point of view these enhancements demand high reliability; time bound delivery and inevitable channel access. In this paper we compare and evaluate the performance of mobility aware clustering based single-hop and multi-hop broadcast network in the IEEE 802.11p standard for different node densities and varying data transfer rates. Simulation results using NS-2 are presented to evaluate various quality of service (QoS) parameters such as, throughput, packet delivery ratio and end to end delay. Significant observations have been made which would envisage further research in this field.

Futuristic device-to-device communication paradigm in vehicular ad-hoc network

Emerging heterogeneous networking is designed to accommodate large volumes of data traffic especially in vehicular environment. As a result, an increased level of QoS requirements and new solutions to ensure fast and reliable data delivery has become indispensable. In this context, device-to-device (D2D) communication technology in 5G network provides a reliable infrastructure which will enable dissemination of various safety and non-safety applications. D2D communication alleviates fast communication between vehicles thereby improving the spectral efficiency, system capacity and throughput and overall performance of the system. This paper develops a paradigm to extend D2D for vehicular infrastructure with the capacity to facilitate vehicular traffic using the LTE band. To analyze the proposed scheme performance, simulations based on LTE network are performed. Results show that our approach provides significant enhancement over IEEE 802.11p standard and LTE-A technology in terms of different performance metrics.

Advances in Quaternary and Pentanary Semiconductors for Communication and Networking Applications

Semiconductors play important role in communication applications right from allowing solar panels to harvest light energy along with acting as the receiver elements of light‐based communication network. These self‐powered nodes allow network of communicating devices to be assembled within the Internet of things, wireless sensor network, mobile/vehicular ad-hoc network and many more potential applications. After initial uses of binary and ternary semiconductors, the research paradigm has now shifted towards quaternary and pentanary semiconductors. These classes of semiconductors are playing dominant role in communication devices because of their flexibility to get easily fabricated by changing the composition of their elemental materials. This paper deals with such novel semiconductors whose properties would certainly leverage the future direction of research in wireless communication systems.

Emerging Technologies, Applications and Futuristic Scope of Cognitive Vehicular Network for 5G Wireless Systems

Research and study on fifth generation (5G) wireless communication systems is growing at a massive rate and has the potential to provide enhanced quality-of-experience (QoE), high spectral availability, less power utilization and less end-to-end latency to the wireless system designers. New wireless applications demand high data rates and mobility thereby urging for a deep excavation on 5G wireless systems. This article presents a heterogeneous network system based framework for 5G wireless systems. It proposes a potential cellular architecture that discusses various emerging and promising schemes for 5G wireless network such as cognitive radio oriented network, massive multiple-input multiple-output (MIMO), effective and energy-efficient communication systems, and visible light communication. The focus of the proposed prototype is on making the most effective use of quality of service (QoS), energy efficiency and spectral efficiency in heterogeneous wireless network and is expected to facilitate the interpretation of critical technical challenges towards spectrum efficient 5G wireless network.