WTRP - wireless token ring protocol

2009 IEEE Conference on Emerging Technologies & Factory Automation, 2009

Support for real-time traffic and multi-hop is a basic requirement in certain applications as, for example, cooperative robot team missions. Normally, point-to-point communication is sufficient to allow such a collaboration. However, there exist situations in which multicast and/or broadcast capabilities, even with real-time requirements, allow a better usage of the available bandwidth leaving more time for unicast communications. This is the case, for example, in which a server generates real-time traffic that has to be delivered to a subset (that can be the whole set) of the nodes of the network. In this paper we present a solution to incorporate the capability of sending multicast messages in token-passing real-time wireless protocols. The solution has been implemented and tested as an extension of RT-WMP (a real-time wireless multi-hop protocol with priority management support). In addition, using these new characteristics, another type of unicast/multicast protocol is proposed, analyzed, evaluated and compared with the plain RT-WMP.

2007 IEEE Internatonal Conference on Mobile Adhoc and Sensor Systems, 2007

Ad-hoc networks usually support best-effort traffic and occasionally some kind of Quality of Service (QoS). However, there are some applications, which generally involve cooperative control, with hard real-time traffic requirements where strict deadlines must be met. To meet deadlines, the communication network has to support the timely delivery of inter-task messages. This is the case, for example, of applications involving cooperative robot teams, such as those used for rescue tasks in hostile environments, emergencies or disaster recovery, where a wired backbone is infeasible or economically unviable. In this paper, we present RT-WMP, a novel protocol that allows wireless real-time traffic in relatively small mobile ad-hoc networks using the low-cost commercial 802.11 technology. The protocol is based on a token-passing approach and message exchange is priority based. Moreover, support for frequent topology changes is provided through the sharing of a matrix that describes link quality amongst the members of the network.

2012 Third International Conference on Intelligent Systems Modelling and Simulation, 2012

In this paper, a proposed new wireless protocol so-called wireless controller area network is introduced. WCAN is an adaptation of its wired cousin, controller area network protocol. The proposed WCAN uses token frame scheme in providing channel access to nodes in the system. This token frame method follows the example used in wireless token ring protocol which is a wireless network protocol that reduces the number of retransmissions as a result of collisions. This scheme based on CAN protocol allows nodes to share a common broadcast channel by taking turns in transmitting upon receiving the token frame that circulates around the network for a specified amount of time. The token frame allows nodes to access the network one at a time, giving 'fair' chance to all nodes instead of competing against one another. This method provides high throughput in a bounded latency environment. The proposed WCAN protocol has been developed and simulated by means of QualNet simulator. The performances of this proposed protocol are evaluated from the perspective of throughput, end-to-end delay and packet delivery ratio, and are compared against the IEEE 802.11 protocol. Simulation results show that the proposed WCAN outperforms IEEE 802.11 based protocol by 62.5 % in terms of throughput with increasing network size. Also, it shows an improvement of 6 % compared to IEEE 802.11 standard at a higher data interval rate.

IEEE Communications Surveys & Tutorials, 2000

WIRELESS MEDIUM ACCESS CONTROL PROTOCOLS he ability to communicate with anyone on the planet from anywhere on the planet has been mankind's dream for a long time. Wireless is the only medium that can enable such untethered communication. With the recent advances in VLSI and wireless technologies, it is now possible to build high-speed wireless systems that are cheap as well as easy to install and operate. However, the wireless medium is a broadcast medium, and therefore multiple devices can access the medium at the same time. Multiple simultaneous transmissions can result in garbled data, making communication impossible. A medium access control (MAC) protocol moderates access to the shared medium by defining rules that allow these devices to communicate with each other in an orderly and efficient manner. MAC protocols therefore play a crucial role in enabling this paradigm by ensuring efficient and fair sharing of the scare wireless bandwidth. Wireless MAC protocols have been studied extensively since the 1970s. The initial protocols were developed for data and satellite communications. We are now witnessing a convergence of the telephone, cable and data networks into a single unified network that supports multimedia and real-time applications like voice and video in addition to data. The multimedia applications require delay and jitter guarantees from the network. This demand of the network is known as the Quality of Service (QoS) guarantee. These requirements have led to novel and complex MAC protocols that can support multimedia traffic. This article surveys the various MAC protocols that have been proposed in the literature and compares them based on architecture (MAC coordination , duplexing), performance (throughput, delay, stability, contention resolution algorithms and fairness) and multimedia support (scheduling, access priorities). We confine our study to systems that span relatively small areas. The article is organized as follows. First we contrast different wireless network architectures. We then bring out the issues unique to wireless MAC protocols. The performance metrics used to compare different MAC protocols are discussed later. We then present a classification of the protocols. We will present the different classes of proposed MAC protocols and compare the pros and cons of the proposed protocols. GENERAL NETWORK CONCEPTS A wireless network is comprised of devices with wireless adapters communicating with each other using radio waves. These wireless devices are called nodes in this dissertation. The signal transmitted can be received only within a certain distance from the sender, which is called the range of the node. A base station (BS) is a special node in the network that is not mobile and is located in a central location. Wireless networks differ in the duplexing mechanism and the network architecture.

Proceedings of the …, 1988

Imtreductlem The popularity of local area networks (LAN) derives from their ability to meet requirements for equipment configuration, transactIon throughput, cabling plant elegance, managesent, and growth as an institution's information needs expand. Of the several LAN types, Ethernet, ...

Computer Communications, 2011

Wireless mesh networks (WMNs) with chain topologies are very useful in road and railroad transportation or in tunnel and mine applications. The proposed protocols for WMNs usually support best-effort traffic or some kind of Quality of Service (QoS). However, some applications such as remote-controlled machines in industrial control networks have hard real-time (HRT) requirements, i.e., strict deadlines. For this reason, this paper incorporates the Packet Delivery Ratio (PDR) metric into the WICKPro (WIreless Chain networK Protocol) protocol, a HRT protocol for WMNs with chain topologies which uses a token-passing approach. WICKPro is a Medium Access Control (MAC) protocol based on the ideas of the Timed-token protocol and the cyclic executive. The incorporation of the PDR metric lets calculate the needed time to be reserved where packet retransmissions can be accommodated while satisfying HRT traffic constraints. Moreover, the feasibility of using the PDR metric in a token-passing protocol is shown. Since WICKPro has been designed to work on top of IEEE 802.11, we made a testbed using commercial 802.11 wireless cards and compared the WICKPro's performance with the 802.11 protocol and three specific protocols for WMNs with chain topologies.

Journal of Communications Software and Systems, 2019

A wireless sensor network is a collection of batterypowered sensor nodes distributed in a geographical area. Inmany applications, such networks are left unattended for along period of time. These networks suffer from the problemslike high energy consumption, high latency time, and end- to-end low packet delivery ratio. To design a protocol that findsa trade-off between these problems is a challenging task. Inorder to mitigate energy consumption issue, different existingMedia Access Control (MAC) protocols such as S-MAC, RMAC,HEMAC, and Congestion-less Single Token MAC protocols havebeen proposed which ensure better packet delivery but fail toensure energy efficiency due to high end-to-end latency. Theproblem of high end-to-end latency is resolved with the existingrouting protocols such as Fault Tolerant Multilevel Routingprotocol (FMS)and Enhanced Tree Routing (ETR) protocol.AS2-MAC and Multi Token based MAC protocol are able toimprove the end-to-end packet delivery ratio. However, ...

… , Chia, Sardegna, Italy, 2002

… , IEEE Transactions on, 2007

Currently, there is a trend towards the implementation of industrial communication systems using wireless networks. However, keeping up with the timing constraints of real-time traffic in wireless environments is a hard task. The main reason is that real-time devices must share the same communication medium with timing unconstrained devices. The VTP-CSMA architecture has been proposed to deal with this problem. It considers an unified wireless system in one frequency band, where the communication bandwidth is shared by real-time and non-real-time communicating devices. The proposed architecture is based on a virtual token passing (VTP) procedure that circulates a virtual token among real-time devices. This virtual token is complemented by an underlying traffic separation mechanism that prioritizes the real-time traffic over the non-real-time traffic. This is one of the most innovative aspects of the proposed architecture, as most part of real-time communication approaches are not able to handle timing unconstrained traffic sharing the same communication medium. A ring management procedure for the VTP-CSMA architecture is also proposed, allowing real-time stations to adequately join/leave the virtual ring.

2012 IEEE 26th International Conference on Advanced Information Networking and Applications, 2012

A wireless sensor network is a collection of batterypowered sensor nodes distributed in a geographical area. There are many applications, where networks are left unattended for a long period of time. These networks suffer from problems like high energy consumption, high latency time, and end-to-end low packet delivery ratio. To design a protocol that finds a trade-off between these problems is a challenging task. In order to mitigate the above issues, different existing Media Access Control (MAC) protocols such as S-MAC, RMAC, HEMAC, Congestion-less Single Token, AS2-MAC, and Multi Token based MAC protocols have been proposed which ensure better packet delivery but fail to ensure energy efficiency due to high end-to-end latency. The problem of high end-to-end latency is resolved with the existing routing protocols such as Fault Tolerant Multilevel Routing protocol(FMS), and Enhanced Tree Routing protocol(ETR). So, it is clear that MAC and routing protocols both together can give better results related to data transmission in WSN. In order to achieve the same, in this paper, we propose a MAC-cum-Routing protocol collision free data Transmission, which improves throughput with respect to end to end packet delivery. The proposed protocol exchanges various control messages among the sensor nodes in a distributed manner to achieve better data packet delivery and ultimately uses tokens to ensure collision free data transmission. Simulation studies of the proposed approach have been carried out and its performance has been compared with the Multi Token based MAC protocol, AS-MAC protocol, and ETR routing protocol. The experimental results based on simulation confirms that the proposed approach has a higher data packet delivery ratio.