A MAC protocol for wireless sensors in a fixed chain topology

Personal and Ubiquitous Computing, 2008

Wireless sensor networks (WSN) are designed for data gathering and processing, with particular requirements: low hardware complexity, low energy consumption, special traffic pattern support, scalability, and in some cases, real-time operation. In this paper we present the virtual TDMA for sensors (VTS) MAC protocol, which intends to support the previous features, focusing particularly on real-time operation. VTS adaptively creates a TDMA arrangement with a number of timeslots equal to the actual number of nodes in range. Thus, VTS achieves an optimal throughput performance compared to TDMA protocols with fixed size of frame. The frame is set up and maintained by a distributed procedure, which allows sensors to asynchronously join and leave the frame. In addition, duty cycle is increased or decreased in order to keep latency constant below a given deadline. Therefore, a major advantage of VTS is that it guarantees a bounded latency, which allows soft real-time applications.

Proceedings of the 2009 Fourth International Conference on Systems and Networks Communications, 2009

This paper proposes a media access control (MAC) layer protocol scheme that is suitable for characteristics of sensor networks (SNs). Among important attributes of SNs are limitation on power consumption, high density of nodes and topology changes. Based on time-division multiple access (TDMA) and frequency division multiple access (FDMA), we offer Multi channel sensor network MAC (MCSMAC) as a novel MAC layer protocol that is more suitable for applications with high density and/or frequent topology changes. The primary goal of MCSMAC is improved energy efficiency in sensor nodes which is achieved by low duty-cycle (with turning radio off) and by overhearing avoidance. Simulation results for three different topologies under variant traffic loads show that, in general, MCSMAC has lower energy consumption whilst yielding in relatively reduced latency compared to SMAC, SMACS and IEEE 802.11.

2016

Wireless Sensor Networks (WSNs) are distributed and interconnected wirelessly sensors that are used in a variety of fields of our daily life, such as the manufacturing, utility operations and traffic monitoring. Many WSN applications come with some technical weaknesses and issues, especially when they are used in Intelligent Transportation Systems (ITS). For ITS applications that use a fixed chain topology which contains road studs deployed at ground level, there are some challenges related to radio propagation, energy constraints and the Media Access Control (MAC) protocol. This thesis develops a ground level radio propagation model for communication between road studs, and energy efficiency metrics to manage the resources to overcome the energy constraints, as well as a MAC protocol compatible with chain topology and ground level communication. For the challenges of the physical layer, this thesis investigates the use of a WSN for communicating between road-based nodes. These node...

2010

Due to the half-duplex property of the sensor radio and the broadcast nature of wireless medium, limited bandwidth remains a pressing issue for wireless sensor networks (WSNs). The design of multi-channel MAC protocols has attracted the interest of many researchers as a cost effective solution to meet the higher bandwidth demand for the limited bandwidth in WSN. In this paper, we present a scheduled-based multi-channel MAC protocol to improve network performance. In our protocol, each receiving node selects (schedules) some timeslot(s), in which it may receive data from the intending sender(s). The timeslot selection is done in a conflict free manner, where a node avoids the slots that are already selected by others in its interference range. To minimize the conflicts during timeslot selection, we propose a unique solution by splitting the neighboring nodes into different groups, where nodes of a group may select the slots allocated to that group only. We demonstrate the effectiveness of our approach thorough simulations in terms of performance parameters such as aggregate throughput, packet delivery ratio, end-to-end delay, and energy consumption.

2011 7th International Wireless Communications and Mobile Computing Conference, 2011

The use of wireless sensor networks is essential for implementation of information and control technologies in precision agriculture. We present our design of network stack for such an application where sensor nodes periodically collect data from fixed locations in a field. Our design of the physical (PHY) layer consists of multiple power modes in both the receive and transmit operations for the purpose of achieving energy savings. In addition, MAC layer is designed which uses these multiple power modes to save energy during the wake-up synchronization phase. We also present analytical models and simulation studies to compare the energy consumption of our MAC protocol with that of the popular S-MAC protocol and show that our protocol has better energy efficiency as well as latency in a periodic data collection application.

Wireless Sensor Networks(WSNs) detect events using one or more sensors, then collect data from detected events using these sensors. This data is aggregated and forwarded to a base station(sink) through wireless communication to provide the required operations. Different kinds of MAC and routing protocols need to be designed for WSN in order to guarantee data delivery from the source nodes to the sink. Some of the proposed MAC protocols for WSN with their techniques, advantages and disadvantages in the terms of their suitability for real time applications are discussed in this paper. We have concluded that most of these protocols can not be applied to real time applications without improvement

2006

Wireless Sensor Networks (WSN) are designed for data gathering and processing, with particular requirements and constraints: low hardware complexity, low energy consumption, special traffic pattern support, scalability, and in some cases, real-time operation. In this paper we present the Virtual TDMA for Sensors (VTS) MAC protocol, which intends to support the previous features, focusing particularly on real-time operation. VTS adaptively creates a TDMA arrangement with a number of timeslots equal to the actual number of nodes in range. Thus, VTS achieves an optimal throughput performance compared to TDMA protocols with fixed size of frame. The TDMA frame is set up and maintained by a distributed procedure, which allows sensors to asynchronously join and leave the frame. A major advantage of VTS is that it guarantees a bounded latency, which allows soft real-time applications. An expression for the upper latency bound is also provided in this paper. VTS performance is evaluated by simulation. Results show less power consumption than other proposals in the field. We also introduce a novel multi-hop operation by coordinated sleep/awake cycles among clusters.

MILCOM 2007 - IEEE Military Communications Conference, 2007

In this paper, we present a new medium access control (MAC) protocol for wireless sensor networks with periodic monitoring applications. In particular, we design a listensleep time schedule for sensor nodes, and we propose a path establishment algorithm for route selection. To evaluate the performance of the proposed protocol, we conduct detailed analysis and simulations. Numerical results show that, compared to existing MAC protocols, our new protocol can significantly reduce energy consumption, average packet delay, and packet loss due to collisions.

In this paper a H-MAC protocol (Hybrid Medium Access Control protocol) has been proposed, which is an energy efficient and low latency MAC protocol which uses node ID method to assign priority for certain wireless sensor nodes that are assumed to be present in critical loops for an industrial process control domain. H-MAC overcomes some of the limitations in the existing approaches. In the case of industrial automation scenario, certain sensor loops are found to be time critical, where data’s have to be transferred without any further delay, as failure in immediate transmission leads to catastrophic results for humans as well as machinery in industrial domain. The proposed H-MAC protocol is simulated in NS2 environment, from the result it is observed that the proposed protocol provides better performance compared to the conventional MAC protocols mentioned in the recent literature for the conceded problem. A MAC protocol which provides both energy saving mechanism and that can handle emergency situation is the most desired for any industry. In any industry time and mission critical scenarios requires strict timeliness and reliability along with the energy efficiency. However there are dynamic and harsh environmental conditions for which the MAC protocol must survive and do transmission accordingly. The dynamic changes in topology must also be adapted so that the nodes are in constant link to the destination. Most of the existing MAC protocols have been identified as they face a number of limitations for industrial application domain.

IOSR Journal of Engineering, 2013

we investigate the following fundamental question-how fast can information be collected from a wireless sensor network organized as tree structure? To address this, we discover and evaluate a number of different techniques using realistic simulation models under the many-to-one communication paradigm known as convergecast. We primarily consider time scheduling on a single frequency channel with the aim of minimizing the number of time slots required (schedule length) to complete a convergecast. Secondarily, we combine scheduling with transmission power control to mitigate the effects of interference, and illustrate that while power control helps in reducing the schedule length under a single frequency. We also illustrate the performance of various channel assignment methods and find empirically that for moderate size networks of about 80 nodes, the use of multi-frequency scheduling can suffice to eliminate most of the interference. The data collection rate is no longer remains limited by interference but by the topology of the routing tree. To this conclude we construct degree-constrained spanning trees and capacitated minimal spanning trees. Finally, we evaluate the impact of different interference and channel models on the schedule length.