IEEE 802.11ad specifies a hybrid medium access control (MAC) protocol consisting of contention as well as non-contention-based channel access mechanisms. It also employs directional antennas to compensate for the high free-space path loss observed in 60 GHz frequency band. Therefore, it significantly differs from other IEEE 802.11(b/g/n/ac) MAC protocols and thus requires new methods to analyze its performance. We propose a new analytical model for performance analysis of IEEE 802.11ad employing a 3-D Markov chain considering all the features of IEEE 802.11ad medium access mechanisms including the presence of non-contention access and the different number of sectors due to the use of directional antennas. We show that the number of sectors has a high impact on the network throughput. We show that the MAC packet delay is significantly affected by the duration of the contention period. Our results indicate that a suitable choice of the number of sectors and contention period can improve the channel utilization and MAC delay performance.

Performance Analysis of IEEE 802.11ad MAC Protocol

Evaluating five different adaptive decomposition methods for EEG signal seizure detection and classification

In the Internet of Things (IoT) era, vehicles and other intelligent components in an intelligent transportation system (ITS) are connected, forming vehicular networks (VNs) that provide efficient and safe traffic and ubiquitous access to various applications. However, as the number of nodes in an ITS increases, it is challenging to satisfy a varied and large number of service requests with different quality of service (QoS) and security requirements in highly dynamic VNs. Intelligent nodes in VNs can compete or cooperate for limited network resources to achieve the objective for either an individual or a group. Game theory (GT), a theoretical framework designed for strategic interactions among rational decision makers sharing scarce resources, can be used to model and analyze individual or group behaviors of communicating entities in VNs. This paper primarily surveys the recent developments of GT in solving various challenges of VNs. This survey starts with an introduction to the background of VNs. A review of GT models studied in the VNs is then introduced, including the basic concepts, classifications, and applicable vehicular issues. After discussing the requirements of VNs and the motivation of using GT, a comprehensive literature review on GT applications in dealing with the challenges of current VNs is provided. Furthermore, recent contributions of GT to VNs that are integrated with diverse emerging 5G technologies are surveyed. Finally, the lessons learned are given, and several key research challenges and possible solutions of applying GT in VNs are outlined.

Applications of Game Theory in Vehicular Networks: A Survey

MAC protocols with dynamic interval schemes for VANETs

All-fiber 2 μm thulium-doped mode-locked fiber laser based on MoSe2-saturable absorber

Free Space Optical communication (FSO) is a wireless communication technology which uses light to transmit the data in free space. FSO has advantages like unlicensed spectrum and higher bandwidth. In this paper FSO system merits and demerits, challenges in FSO, and various channel models are discussed. To mitigate the turbulence in FSO the mitigation techniques like relaying, diversity schemes and adopting different modulation techniques used in different channels are discussed and its performance comparison is given.

A review on channel models in free space optical communication systems

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.

Performance analysis of contention-based access periods and service periods of 802.11ad hybrid medium access control

A survey on hybrid MAC protocols for vehicular ad-hoc networks

We present an analytical model for the access during the Service Periods (SP) of the IEEE 802.11ad Hybrid Medium Access Control protocol. As a performance measure of this protocol, we derive the worst case and average delay faced by the SP packets. We show that as the arrival rate of the SP packets increases, the delay increases linearly till a point, beyond which it grows exponentially. Further, we extend the model to variable length of beacon interval, and random allocation of SPs to the nodes. We show how a network designer can do optimal allocation of the SP and the CBAP duration to achieve a tradeoff between SP delay and CBAP throughput. We further extend our analysis for the case of heterogeneous system. Our analytical results are compared with simulation and the results show a good match.

Performance Analysis of Service Periods (SP) of the IEEE 802.11ad Hybrid MAC Protocol

In our day to day life we witness an increase in population thereby a sudden increase of vehicles on roads causing major traffic jams and delays. There always exists an emergency situation where we require the movement of ambulances and fire engines to reach its destination on time. Due to bad traffic situations this event fails to happen. This paper proposes an automatic green channel facility during heavy traffic for an emergency vehicle in a particular lane. Vehicular Ad-Hoc Networks (VANET) is an effective method of communication between the emergency vehicle, the traffic lights (infrastructure) and the other vehicles. A traffic scenario is created to evaluate the performance of communication between the moving nodes, road side units and the traffic lights, till the vehicle successfully reaches its destination. VANET is an advanced application of Mobile Ad Hoc Network (MANET), which can easily optimize road traffic as well as improve safety so as to provide an intelligent transport system. The proposed research paper is analyzed through a real-time vehicle traffic scenario simulation and then evaluated through a series of simulation using network simulator.

C. Hemanth

Papers

A review on channel models in free space optical communication systems

Performance analysis of contention-based access periods and service periods of 802.11ad hybrid medium access control

A survey on hybrid MAC protocols for vehicular ad-hoc networks

Performance Analysis of Service Periods (SP) of the IEEE 802.11ad Hybrid MAC Protocol

Emergency Vehicle Signalling Using VANETS