Multi-channel distributed coordinated function over single radio in wireless sensor networks

Multi-channel assignments are becoming the solution of choice to improve performance in single radio for wireless networks. Multi-channel allows wireless networks to assign different channels to different nodes in real-time transmission. In this paper, we propose a new approach, Multi-channel Distributed Coordinated Function (MC-DCF) which takes advantage of multi-channel assignment. The backoff algorithm of the IEEE 802.11 distributed coordination function (DCF) was modified to invoke channel switching, based on threshold criteria in order to improve the overall throughput for wireless sensor networks (WSNs) over 802.11 networks. We presented simulation experiments in order to investigate the characteristics of multi-channel communication in wireless sensor networks using an NS2 platform. Nodes only use a single radio and perform channel switching only after specified threshold is reached. Single radio can only work on one channel at any given time. All nodes initiate constant bit rate streams towards the receiving nodes. In this work, we studied the impact of non-overlapping channels in the 2.4 frequency band on: constant bit rate (CBR) streams, node density, source nodes sending data directly to sink and signal strength by varying distances between the sensor nodes and operating frequencies of the radios with different data rates. We showed that multi-channel enhancement using our proposed algorithm provides significant improvement in terms of throughput, packet delivery ratio and delay. This technique can be considered for WSNs future use in 802.11 networks especially when the IEEE 802.11n becomes popular thereby may prevent the 802.15.4 network from operating effectively in the 2.4 GHz frequency band

Multi-Channel Multi-Radio Using 802.11 Based Media Access for Sink Nodes in Wireless Sensor Networks

The next generation surveillance and multimedia systems will become increasingly deployed as wireless sensor networks in order to monitor parks, public places and for business usage. The convergence of data and telecommunication over IP-based networks has paved the way for wireless networks. Functions are becoming more intertwined by the compelling force of innovation and technology. For example, many closed-circuit TV premises surveillance systems now rely on transmitting their images and data over IP networks instead of standalone video circuits. These systems will increase their reliability in the future on wireless networks and on IEEE 802.11 networks. However, due to limited non-overlapping channels, delay, and congestion there will be problems at sink nodes. In this paper we provide necessary conditions to verify the feasibility of round robin technique in these networks at the sink nodes by using a technique to regulate multi-radio multichannel assignment. We demonstrate through simulations that dynamic channel assignment scheme using multi-radio, and multichannel configuration at a single sink node can perform close to optimal on the average while multiple sink node assignment also performs well. The methods proposed in this paper can be a valuable tool for network designers in planning network deployment and for optimizing different performance objectives

Multi-Channel Distributed Coordinated Function over Single Radio in Wireless Sensor Networks

Multi-channel assignments are becoming the solution of choice to improve performance in single radio for wireless networks. Multi-channel allows wireless networks to assign different channels to different nodes in real-time transmission. In this paper, we propose a new approach, Multi-channel Distributed Coordinated Function (MC-DCF) which takes advantage of multi-channel assignment. The backoff algorithm of the IEEE 802.11 distributed coordination function (DCF) was modified to invoke channel switching, based on threshold criteria in order to improve the overall throughput for wireless sensor networks (WSNs) over 802.11 networks. We presented simulation experiments in order to investigate the characteristics of multi-channel communication in wireless sensor networks using an NS2 platform. Nodes only use a single radio and perform channel switching only after specified threshold is reached. Single radio can only work on one channel at any given time. All nodes initiate constant bit rate streams towards the receiving nodes. In this work, we studied the impact of non-overlapping channels in the 2.4 frequency band on: constant bit rate (CBR) streams, node density, source nodes sending data directly to sink and signal strength by varying distances between the sensor nodes and operating frequencies of the radios with different data rates. We showed that multi-channel enhancement using our proposed algorithm provides significant improvement in terms of throughput, packet delivery ratio and delay. This technique can be considered for WSNs future use in 802.11 networks especially when the IEEE 802.11n becomes popular thereby may prevent the 802.15.4 network from operating effectively in the 2.4 GHz frequency band

Energy efficient multi channel packet forwarding mechanism for wireless sensor networks in smart grid applications

Multichannel Wireless Sensor Networks (MWSNs) paradigm provides an opportunity for the Power Grid (PG) to be upgraded into an intelligent power grid known as the Smart Grid (SG) for efficiently managing the continuously growing energy demand of the 21st century. However, the nature of the intelligent grid environments is affected by the equipment noise, electromagnetic interference, and multipath effects, which pose significant challenges in existing schemes to find optimal vacant channels for MWSNs-based SG applications. This research proposed three schemes to address these issues. The first scheme was an Energy Efficient Routing (ERM) scheme to select the best-optimized route to increase the network performance between the source and the sink in the MWSNs. Secondly, an Efficient Channel Detection (ECD) scheme to detect vacant channels for the Primary Users (PUs) with improved channel detection probability and low probability of missed detection and false alarms in the MWSNs. Finally, a Dynamic Channel Assignment (DCA) scheme that dealt with channel scarcities by dynamically switching between different channels that provided higher data rate channels with longer idle probability to Secondary Users (SUs) at extremely low interference in the MWSNs. These three schemes were integrated as the Energy Efficient Multichannel Packet Forwarding Mechanism (CARP) for Wireless Sensor Networks in Smart Grid Applications. The extensive simulation studies were carried through an EstiNet software version 9.0. The obtained experimental simulation facts exhibited that the proposed schemes in the CARP mechanism achieved improved network performance in terms of packets delivery ratio (26%), congestion management (15%), throughput (23%), probability of channel detection (21%), reduces packet error rate (22%), end-to-end delay (25%), probability of channel missed-detection (25%), probability of false alarms (23.3%), and energy consumption (17%); as compared to the relevant schemes in both EQSHC and G-RPL mechanisms. To conclude, the proposed mechanism significantly improves the Quality of Service (QoS) data delivery performance for MWSNs in SG

Efecto de ancho de banda de los canales en redes IEEE 802.11

El principal propósito de este trabajo es llevar a cabo un estudio del rendimiento de los canales de la red 802.11 con señales de 20 y 40 MHz, mediante el uso de channel bonding. Con lo anterior se pretende identificar la mejor configuración para la combinación de canales en la que se pueda mantener una alta velocidad al tiempo que se reduce el impacto de las interferencias, especialmente en la banda de frecuencias de 2,4 GHz.The main objective of this work is to carry out a study of the throughput of 802.11 network channels with 20 and 40 MHz signals, using channel bonding. The aim is to identify the best configuration for channel bonding in which high speed can be maintained while reducing the impact of interference, especially in the 2.4 GHz frequency band.Grado en Ingeniería Telemátic

An efficient multichannel wireless sensor networks MAC protocol based on IEEE 802.11 distributed co-ordinated function.

This research aimed to create new knowledge and pioneer a path in the area relating to future trends in the WSN, by resolving some of the issues at the MAC layer in Wireless Sensor Networks. This work introduced a Multi-channel Distributed Coordinated Function (MC-DCF) which takes advantage of multi-channel assignment. The backoff algorithm of the IEEE 802.11 distributed coordination function (DCF) was modified to invoke channel switching, based on threshold criteria in order to improve the overall throughput for wireless sensor networks. This work commenced by surveying different protocols: contention-based MAC protocols, transport layer protocols, cross-layered design and multichannel multi-radio assignments. A number of existing protocols were analysed, each attempting to resolve one or more problems faced by the current layers. The 802.15.4 performed very poorly at high data rate and at long range. Therefore 802.15.4 is not suitable for sensor multimedia or surveillance system with streaming data for future multichannel multi-radio systems. A survey on 802.11 DCF - which was designed mainly for wireless networks –supports and confirm that it has a power saving mechanism which is used to synchronise nodes. However it uses a random back-off mechanism that cannot provide deterministic upper bounds on channel access delay and as such cannot support real-time traffic. The weaknesses identified by surveying this protocol form the backbone of this thesis The overall aim for this thesis was to introduce multichannel with single radio as a new paradigm for IEEE 802.11 Distributed Coordinated Function (DCF) in wireless sensor networks (WSNs) that is used in a wide range of applications, from military application, environmental monitoring, medical care, smart buildings and other industry and to extend WSNs with multimedia capability which sense for instance sounds or motion, video sensor which capture video events of interest. Traditionally WSNs do not need high data rate and throughput, since events are normally captured periodically. With the paradigm shift in technology, multimedia streaming has become more demanding than data sensing applications as such the need for high data rate protocol for WSN which is an emerging technology in this area. The IEEE 802.11 can support data rates up to 54Mbps and 802.11 DCF was designed specifically for use in wireless networks. This thesis focused on designing an algorithm that applied multichannel to IEEE 802.11 DCF back-off algorithm to reduce the waiting time of a node and increase throughput when attempting to access the medium. Data collection in WSN tends to suffer from heavy congestion especially nodes nearer to the sink node. Therefore, this thesis proposes a contention based MAC protocol to address this problem from the inspiration of the 802.11 DCF backoff algorithm resulting from a comparison of IEEE 802.11 and IEEE 802.15.4 for Future Green Multichannel Multi-radio Wireless Sensor Networks

Multichannel Cross-Layer Routing for Sensor Networks

Wireless Sensor Networks are ad-hoc networks that consist of sensor nodes that typically use low-power radios to connect to the Internet. The channels used by the low-power radio often suffer from interference from the other devices sharing the same frequency. By using multichannel communication in wireless networks, the effects of interference can be mitigated to enable the network to operate reliably. This thesis investigates an energy efficient multichannel protocol in Wireless Sensor Networks. It presents a new decentralised multichannel tree-building protocol with a centralised controller for ad-hoc sensor networks. The proposed protocol alleviates the effect of interference, which results in improved network efficiency, stability, and link reliability. The protocol detects the channels that suffer interference in real-time and switches the sensor nodes from those channels. It takes into account all available channels and aims to use the spectrum efficiently by transmitting on several channels. In addition to the use of multiple channels, the protocol reconstructs the topology based on the sensor nodes’ residual energy, which can prolong the network lifetime. The sensor nodes’ energy consumption is reduced because of the multichannel protocol. By using the lifetime energy spanning tree algorithm proposed in this thesis, energy consumption can be further improved by balancing the energy load in the network. This solution enables sensor nodes with less residual energy to remain functional in the network. The benefits of the proposed protocol are described in an extensive performance evaluation of different scenarios in this thesis