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Advances in autonomous vehicular technology facilitate the development of intelligent traffic regulation systems. Such a system aims to configure and regulate vehicular mobility patterns to enhance in-road transportation safety and efficiency. To effectively function, the autonomous system must enable high-rate communications and rapid dissemination of vehicle-to-vehicle messaging flows. Instead of...
Wireless networked control systems have gained significant popularity due to commissioning and maintenance ease. IEEE 802.15.4 standard is one of wireless communication protocol for low delay deterministic network. Factory automation, not only needs low delay but also requires the network that should has the capacity of various delay devices. In this paper, we propose a scheme, satisfying the muli-delay...
Along with the development of industrial systems, real-time Ethernet (RTE) is widely utilized for control systems. S-TDMA is one of the RTE protocols, and it is a concept realizing a coexistence of real-time and best-effort communication over the Ethernet by time-division multiplexing. In previous work, a special switching hub capable of S-TDMA was implemented, and the capability of real-time communication...
The rapid development of medical sensors has increased the interest in Wireless Body Area Network (WBAN) applications where physiological data from the human body and its environment is gathered, monitored, and analyzed to take the proper measures. In WBANs, it is essential to design MAC protocols that ensure adequate Quality of Service (QoS) such as low delay and high scalability. This paper investigates...
Coping with customer interests to employ Wireless Sensor Networks (WSN) in the new applications requires dealing with the fact of nodes variety that implies the heterogeneous nature of the traffic. This necessitates employing differentiation techniques that lead in the end to implementing prioritization in some processes of the system. The medium access controlling process plays a main role in the...
In sensor network deployed sensor nodes send data to the sink node. Set of different kind of sensor nodes called sensor network. This paper shows the behavior and performance of FMAC Protocol for different reporting rates. Results for packet delivery ratio, packet loss ratio, average throughput, average energy consumption, Average end-to-end delay and control overheads shows as graphical representation...
Industrial wireless sensor and actuator networks are gaining momentum and have started to target new and more demanding application scenarios extending pure monitoring scenarios. In this paper we discuss the needs for simple and more accurate TDMA timing synchronization to enable the future applications. We present a novel TDMA timing synchronization protocol which is simple to implement, as well...
Vehicular-to-Vehicular (V2V) and Vehicular-to-Infrastructure (V2I) communications in Vehicular Ad hoc Network (VANET) environment rely mainly on Medium Access Control (MAC) to minimize the delay and maintain reliable access to the communication medium. IEEE 802.11p standard is developed to achieve these goals. However its performance deteriorates drastically in large networks due to the high level...
Wireless networks have become a very attractive solution for soft real-time data transport in the industry. For such technologies to carry real-time traffic, reliable bounds on end-to-end communication delays have to be ascertained to warrant a proper system behavior. As for legacy wired embedded and real-time networks, two main wireless multiple access methods can be leveraged: (i) time division...
Industrial applications have been shifting towards wireless multi-hop networks in recent years due to their lower cost of deployment and reconfiguration compared with their wired counterparts. These wireless networks usually must support real-time communication to meet the application requirements. For this reason, Wireless Mesh Networks (WMNs) are potential candidates for industrial applications...
To overcome the weak points that protocol sequence allocation in vehicular ad hoc networks heavily relies on the help of infrastructures and that a large amount of sequence resource is wasted due to the one-to-one scheme, in this paper we propose a comprehensive framework based on which users could take full use of the sequence resource and at the same time adaptively avoid inter-vehicle interference...
The long propagation delay and the high bit error rate of underwater acoustic channel greatly affect the performance efficiency of underwater acoustic networks (UWANs). In this paper, we propose three ARQ schemes for UWANs, namely selective repeat-ARQ, Type-I Hybrid ARQ and Type-II Hybrid ARQ, where the transmissions of data and acknowledgment packets are interlaced. The proposed ARQ schemes are designed...
The military organizations around the world are increasingly adopting commercial cellular standards for their mission critical communication networks. Most of the cellular standards include support for several new techniques to implement network-wide load balancing to obtain optimum network performance. The goal of this paper is to understand the effect of load balancing on key performance indicators...
We propose a QoS supporting ad hoc network scheme which employs a hybrid approach utilizing both TDMA and 802.11 DCF and present performance evaluation results of the scheme. In the scheme, TDMA period provides contention free transmissions for QoS flows, and DCF period is used to provide contention-based access for best effort or low priority flows. We evaluate the proposed scheme for various numbers...
Mobile devices in industrial settings became commonplace with different handheld equipment and mobile robots using COTS WiFi interfaces for communication. This growth in the use of the wireless medium increases the potential for overload and consequent long delays and high losses. Traffic segregation with different Quality of Service (QoS) classes can attenuate the problem but does not solve it within...
Transmission timing and delay between communicating vehicles are two important performance measures for safety-critical applications of Vehicular Ad-Hoc Networks (VANETS). Safety-Critical VANETS are composed of multiple nodes each requiring access to a shared communication medium. This access is controlled by the Medium Access Control (MAC) protocol. Numerous MAC protocols have been proposed for VANETS,...
Design-time analysis and verification of distributed real-time embedded systems necessitates the modeling of the time-varying performance of the network and comparing that to application requirements. Earlier work has shown how to build a system network model that abstracted away the network's physical medium and protocols which govern its access and multiplexing. In this work we show how to apply...
Asynchronous distributed system is hard to realize time division multiplexing. In order to synchronize a distributed system, we introduce IEEE 1588 protocol. IEEE 1588 protocol is a precision time synchronization protocol which can synchronize time in sub-microsecond (10"6 second) range for the purpose of realizing time division multiplexing. The performance of precision time synchronization...
We propose a QoS supporting ad hoc network protocol which employs a hybrid approach utilizing both TDMA and 802.11 DCF. TDMA period provides contention free transmissions for QoS flows, and DCF period is used to provide contention-based access for best effort or low priority flows. TDMA time slots are assigned on admission basis in a distributed manner by utilizing network routing information and...
For distributed safety-critical systems, such as avionics and automotive, shared networks represent a bottleneck for timing predictability, a key issue to fulfill certification requirements. To control interferences on such shared resources and guarantee bounded delays, the Time Division Multiple Access (TDMA) protocol is considered as one of the most interesting arbitration protocols due to its deterministic...
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