Clock synchronisation was identified as one of the major challenges following an initial trial of... more Clock synchronisation was identified as one of the major challenges following an initial trial of a prototype underwater radio sensor network (URSN). The network used TDMA and was deployed in shallow sea water (in the tens of meters range). This paper proposes a scheduled level-based energy efficient clock synchronisation protocol (SLE) to ensure the efficient time synchronisation of network sensor nodes. A static prototype sensor network was deployed to validate the protocols performance. Analysis firstly showed, that the more levels (hops) in a network mean that the synchronization precision was poorer and that secondly, increasing the number of TDMA sub slots increases the frequency of synchronisation and thus improves network timing precision. The context of the deployed network was to monitor subsurface coastal erosion, motivated by environmental requirements.
Electromagnetic communications in an underwater environment has been largely dismissed as impract... more Electromagnetic communications in an underwater environment has been largely dismissed as impractical or impossible by researchers in favour of acoustic and optical techniques. Very Low Frequency (VLF) systems do not however suffer from the attenuation experienced at higher frequencies and offer several advantages when compared to optical and acoustic methods particularly in shallow water. This paper describes the design of a flexible MAC protocol for use in a small scale wireless sensor network using VLF technology that is used to provide an underwater coastal monitoring service.
2009 Third International Conference on Sensor Technologies and Applications, 2009
A small scale wireless sensor network was designed using electromagnetic technology in order to p... more A small scale wireless sensor network was designed using electromagnetic technology in order to provide an underwater coastal monitoring service. The sensor nodes were deployed manually, which formed a multi-hop static topology for the network. Data delivery was scheduled via daily cycles of sleeping and waking-up. Due to the unique features of the network, ad-hoc on-demand distance vector was chosen
2009 International Conference on Ultra Modern Telecommunications & Workshops, 2009
Underwater sensor networks have traditionally used acoustic or optical technologies to enable com... more Underwater sensor networks have traditionally used acoustic or optical technologies to enable communication between the network nodes. Electromagnetic communications, although ubiquitous in most atmospheric communications systems, it has been largely dismissed for use in underwater environments because of the huge attenuation of the signal in water. Very low frequency (VLF) electromagnetic signals however do not suffer attenuation as much as
Very low frequency electromagnetic communication system is used in a small scale underwater wirel... more Very low frequency electromagnetic communication system is used in a small scale underwater wireless sensor network for coastal monitoring purposes, as recent research has demonstrated distinct advantages of radio waves compared to acoustic and optical waves in shallow water conditions. This paper describes the detailed TDMA and packet design process for the prototype sensor system. The lightweight protocol is time division based in order to fit the unique characteristics and specifications of the network. Evaluations are based on initial beach trial as well as modeling and simulations.
Underwater electromagnetic (EM) communica-tions were investigated with fervent interest in the la... more Underwater electromagnetic (EM) communica-tions were investigated with fervent interest in the last century up until the 1970s. Because its range is restricted by fundamental attenuation and noise
2009 29th IEEE International Conference on Distributed Computing Systems Workshops, 2009
Most underwater sensor networks choose acoustics as the medium for wireless transmission. However... more Most underwater sensor networks choose acoustics as the medium for wireless transmission. However, electromagnetic waves also offer great merits for transmission in special underwater environment. This paper presents part of the work carried out in a project, entitled ASTEC (Automated Sensing Technologies for Coastal Monitoring), which aims to deploy a small scale wireless sensor network using electromagnetic waves with a multi-hop static topology under shallow water conditions where there is a high level of sediment and aeration in the water column. Data delivery is scheduled via daily cycles of sleeping and waking up to transmit. Due to the unique features of the network, ad-hoc on-demand Distance Vector (AODV) is chosen as the routing protocol. Modeling and simulations are conducted to evaluate network performance in terms of failure tolerance, congestion handling, and optimal grid arrangements. The results demonstrate the likely effectiveness of the designated network for this and similar scenarios.
Clock synchronisation was identified as one of the major challenges following an initial trial of... more Clock synchronisation was identified as one of the major challenges following an initial trial of a prototype underwater radio sensor network (URSN). The network used TDMA and was deployed in shallow sea water (in the tens of meters range). This paper proposes a scheduled level-based energy efficient clock synchronisation protocol (SLE) to ensure the efficient time synchronisation of network sensor nodes. A static prototype sensor network was deployed to validate the protocols performance. Analysis firstly showed, that the more levels (hops) in a network mean that the synchronization precision was poorer and that secondly, increasing the number of TDMA sub slots increases the frequency of synchronisation and thus improves network timing precision. The context of the deployed network was to monitor subsurface coastal erosion, motivated by environmental requirements.
Electromagnetic communications in an underwater environment has been largely dismissed as impract... more Electromagnetic communications in an underwater environment has been largely dismissed as impractical or impossible by researchers in favour of acoustic and optical techniques. Very Low Frequency (VLF) systems do not however suffer from the attenuation experienced at higher frequencies and offer several advantages when compared to optical and acoustic methods particularly in shallow water. This paper describes the design of a flexible MAC protocol for use in a small scale wireless sensor network using VLF technology that is used to provide an underwater coastal monitoring service.
2009 Third International Conference on Sensor Technologies and Applications, 2009
A small scale wireless sensor network was designed using electromagnetic technology in order to p... more A small scale wireless sensor network was designed using electromagnetic technology in order to provide an underwater coastal monitoring service. The sensor nodes were deployed manually, which formed a multi-hop static topology for the network. Data delivery was scheduled via daily cycles of sleeping and waking-up. Due to the unique features of the network, ad-hoc on-demand distance vector was chosen
2009 International Conference on Ultra Modern Telecommunications & Workshops, 2009
Underwater sensor networks have traditionally used acoustic or optical technologies to enable com... more Underwater sensor networks have traditionally used acoustic or optical technologies to enable communication between the network nodes. Electromagnetic communications, although ubiquitous in most atmospheric communications systems, it has been largely dismissed for use in underwater environments because of the huge attenuation of the signal in water. Very low frequency (VLF) electromagnetic signals however do not suffer attenuation as much as
Very low frequency electromagnetic communication system is used in a small scale underwater wirel... more Very low frequency electromagnetic communication system is used in a small scale underwater wireless sensor network for coastal monitoring purposes, as recent research has demonstrated distinct advantages of radio waves compared to acoustic and optical waves in shallow water conditions. This paper describes the detailed TDMA and packet design process for the prototype sensor system. The lightweight protocol is time division based in order to fit the unique characteristics and specifications of the network. Evaluations are based on initial beach trial as well as modeling and simulations.
Underwater electromagnetic (EM) communica-tions were investigated with fervent interest in the la... more Underwater electromagnetic (EM) communica-tions were investigated with fervent interest in the last century up until the 1970s. Because its range is restricted by fundamental attenuation and noise
2009 29th IEEE International Conference on Distributed Computing Systems Workshops, 2009
Most underwater sensor networks choose acoustics as the medium for wireless transmission. However... more Most underwater sensor networks choose acoustics as the medium for wireless transmission. However, electromagnetic waves also offer great merits for transmission in special underwater environment. This paper presents part of the work carried out in a project, entitled ASTEC (Automated Sensing Technologies for Coastal Monitoring), which aims to deploy a small scale wireless sensor network using electromagnetic waves with a multi-hop static topology under shallow water conditions where there is a high level of sediment and aeration in the water column. Data delivery is scheduled via daily cycles of sleeping and waking up to transmit. Due to the unique features of the network, ad-hoc on-demand Distance Vector (AODV) is chosen as the routing protocol. Modeling and simulations are conducted to evaluate network performance in terms of failure tolerance, congestion handling, and optimal grid arrangements. The results demonstrate the likely effectiveness of the designated network for this and similar scenarios.
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Papers by Gordon Dickers