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In industrial applications synchronized sensor nodes are vital for many tasks like multi parameter sampling of complex machinery behavior. The wirelessly connected nodes are usually synchronized to a base station. Therefore, frequency or period estimation of the reference clock is a key issue for all connected tasks like sampling, localization or applying energy optimized communication protocols....
In this paper, we simulate the tri-message time synchronization protocol within the cluster sub net for the MAC layer of underwater acoustic network. Distinguished with the traditional TDMA protocols, all sub nodes are time consistent with the cluster node and the sub nodes can be quickly netted in the improved TDMA protocol. We established a network simulation with a bunch of 6 nodes in OPNET software...
In this paper, we address the fundamental problem of improving the performance of many-to-one and many-to-many communications. Our approach is Time Division Multiple Access (TDMA) based but addresses the limitations of existing TDMA implementations in a novel way. In a nutshell, we combine packets from many senders into a single large packet transmission by exploiting capture effect achieved through...
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...
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...
Current IoT protocols, like the Constrained Application Protocol (CoAP), do not yet provide real-time behavior for the inter-device communication. In this paper, we propose a real-time extension for the CoAP standard that defines interfaces for the time synchronization among nodes and the time slot management. These interfaces enable a controlled exclusive network access based on a Time Division Multiple...
Link-16 is a widely used tactical data link system for battlefield networks. A key component of Link-16 is network time synchronization. Link-16 provides two types of time synchronization methods: global positioning system (GPS)-based time synchronization and GPS-less time synchronization. In particular, Link-16 requires relay nodes for multi-hop time synchronization. However, in Link-16, the relay...
In this paper a novel synchronization method for wireless sensor networks with star topology is presented. We address timing synchronization using low frequency real-time clocks in all nodes. A beacon-driven TDMA-protocol for bidirectional node/base communication is used. Between the beacons, which are sent by the base station, lie the superframe time intervals to handle data transmission from node...
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...
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...
In this paper, I study the receiver synchronized time division multiple access (TDMA) in the presence of propagation delay deviation, which is one of the major parameter to consider for underwater wireless sensor networks. First I describe how the receiver synchronized TDMA protocol can be used in a network without propagation delay deviation. Then I modify the receiver synchronized TDMA to get higher...
In this paper we propose a New Resource Allocation Protocol for tactical scenario based on mobile Ad Hoc networks. A dynamic slot assignment scheme for Time Division Multiple Access (TDMA) under frequency hopping environment is proposed, in which control slots are provided to every node to cater the hidden and exposed terminal problems. As in the tactical scenario voice is the most important service,...
Support for multiple concurrent applications is an important enabler for promoting the use of sensor networks as an infrastructure technology, where multiple users can deploy their applications independently. In such a scenario, different applications on a node may transmit packets at distinct periods, causing the node to change from sleep to active state more often, which negatively impacts the energy...
This paper presents a new MAC protocol: Adaptive Space Time - TDMA (AST-TDMA) for Autonomous Underwater Vehicles (AUV) operating as a swarm in the open ocean. The aim of the protocol is to allow the dissemination of navigational information amongst the vehicles as quickly as possible such that they may operate as a group in a swarm like fashion.
In this paper, a fully distributed synchronization scheme for wide-range TDMA Ad-Hoc networks is described. This synchronization scheme provides a simple algorithm with low overhead requirements to achieve high clock synchronization accuracy in a fully distributed approach. Our work is based on the clock sampling mutual network synchronization (CS-MNS) algorithm. It extends it by including the propagation...
Wireless HART is a state-of-the-art solution for a time-division multiple-access (TDMA) based wireless private area network. It combines slow frequency-hopping and a TDMA scheme that utilizes a centralized a-priori slot allocation mechanism. In this paper we conduct a performance evaluation of the Wireless HART TDMA protocol and provide insights into the major factors impacting energy consumption...
Traditional cooperative communications can improve communication reliability. However, transmissions from multiple relay nodes are challenging in practice. Single transmissions in time-division multiple-access (TDMA) manner cause large transmission delay, but simultaneous transmissions from two or more nodes using frequency-division multiple access (FDMA) and code-division multiple access (CDMA) are...
Tactical data links are an essential contribution to automatic "real-time" communication. In the current tactical environment, most users are pre-allocated a fixed amount of bandwidth. As a result, there should be bandwidth wastes and no guarantee of QoS. If the network is flooded, delaying of important messages may happen. So We need proper network management framework in TDL system. And...
In wireless ad hoc networks, all the mobile nodes are required to be synchronized for TDMA and frequency hopping spread spectrum (FHSS) operations. In this paper, we propose modified automatic selftime-correcting procedure (MASP) to achieve clock synchronization in a multi-hop environment. In MASP a faster node has a higher priority to send its timing information. It has a self correction capability...
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