david darse - Academia.edu (original) (raw)
Papers by david darse
Several different distributed channel assignment algorithms are compared using Unsupervised FDMA ... more Several different distributed channel assignment algorithms are compared using Unsupervised FDMA (UFDMA), a multiple access scheme for the land mobile radio environment. All algorithms make use of coexistence etiquettes which allow different users to share common frequency allocation. It is found that using the Least Interfered Channel (LIC) with call reassignment provides considerably better performance than LIC, and LIC better than First Available (FA). A tight interference level threshold, at the transmitter, improves the performance of the FA algorithm, but it is much better to use a loose interference threshold with the LIC algorithms.
IWISPA 2000. Proceedings of the First International Workshop on Image and Signal Processing and Analysis. in conjunction with 22nd International Conference on Information Technology Interfaces. (IEEE Cat. No.00EX437), 2000
ABSTRACT
This paper explores an efficient Medium Access Control protocol for carrying data traffic via sat... more This paper explores an efficient Medium Access Control protocol for carrying data traffic via satellite. The Combined Free/Demand Assignment Multiple Access (CFDAMA) protocol combines free assignment of data slots with demand assignment, providing a minimum delay of one round trip time at low loads and the statistical multiplexing gains of demand assignment at high loads. The delay/utilisation performance of CFDAMA is explored for both Poisson and selfsimilar traffic models. It is shown for Poisson traffic that CFDAMA provides both extremely low end-to end delay and variance in delay of packet transmissions over a wide range of loads up to 85% of the channel capacity. For self-similar traffic, it has been found that the scheme is limited to a lower maximum channel loading, but performs better at low channel loads. The importance of an accurate traffic model in network performance evaluation is highlighted. Comparisons are made between CFDAMA and the Slotted ALOHA protocol, and it is shown that CFDAMA outperforms Slotted ALOHA over virtually the entire range of channel utilisation.
2006 International Conference on Wireless Communications, Networking and Mobile Computing, 2006
Abstract We measure and evaluate the capacity of an asymmetric multi-hop wireless ad hoc network ... more Abstract We measure and evaluate the capacity of an asymmetric multi-hop wireless ad hoc network from a new perspective using minimum impact routing, which selects a route based on total interference impact measured with total disturbed nodes along an asymmetrical ...
2012 International Symposium on Wireless Communication Systems (ISWCS), 2012
ABSTRACT This paper presents a novel Medium Access Control (MAC) protocol named ALOHA and Q-Learn... more ABSTRACT This paper presents a novel Medium Access Control (MAC) protocol named ALOHA and Q-Learning based MAC with Informed Receiving (ALOHA-QIR) for Wireless Sensor Networks (WSNs). This scheme is implemented by combining frame based Slotted ALOHA and Q-Learning. ALOHA based schemes have the benefits of simplicity, low computation and overheads, but suffer collisions from the blind transmission strategy. By considering the previous transmission experience, Q-Learning offers nodes certain intelligence to access slots with a lower probability of collision. During data transmissions, receivers are informed by transmitters about their future slot selections so that the receivers can turn off their radio in other slots to save energy. Compared with basic Slotted ALOHA, ALOHA-QIR obtains significant improvements in throughput, delay and energy efficiency.
Some services which are provided by satellite, or which may in future by provided by High-Altitud... more Some services which are provided by satellite, or which may in future by provided by High-Altitude Platform (HAP) networks, can be configured to tolerate short link outages without loss of service. If the shortest fades can be `bridged¿, this will reduce the failure rate of services. The two most common causes of outage in mm-wave links, which require line-of-sight propagation, direct from Satellites or High-Altitude Platforms (HAPs) to a moving train are heavy rain and tunnels. It is shown that ability to tolerate outages of up to 30 minutes enables the delivery of content at 99.9% availability in an extremely rainy location such as Singapore, a service which would otherwise not be possible. The improvements offered to services on trains by exploiting antenna site diversity and caching are also evaluated.
IET Conference on Wireless Sensor Systems (WSS 2012), 2012
ABSTRACT In this paper, an ALOHA based Medium Access Control (MAC) protocol (RL-ALOHA with Inform... more ABSTRACT In this paper, an ALOHA based Medium Access Control (MAC) protocol (RL-ALOHA with Informed Receiving) is proposed for multi-hop Wireless Sensor Networks (WSNs), which overcomes the traditional problems of low throughput, while exploiting their advantages of simplicity, low computational complexity and overheads. Reinforcement Learning (RL) is implemented as an intelligent slot assignment strategy in order to avoid collisions with minimal additional overheads. To improve the energy efficiency, Informed Receiving (IR) and ping packets are applied to avoid idle listening and overhearing. The simulation results show that this approach significantly increases the energy efficiency, achieves over twice throughput of Slotted ALOHA and reduces the end-to-end delay.
The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2002
Channel assignment strategies for use with a high altitude platform, spot beam architecture are e... more Channel assignment strategies for use with a high altitude platform, spot beam architecture are examined. A novel power roll-off approximation is derived to allow terrestrial simulation tools to be used, and simulation performance is compared with a theoretical lower bound derived from the Engset distribution. It is shown that the use of cell overlap considerably e nhances the blocking probability performance, in addition to boosting flexibility.
GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489), 2003
An investigation is performed into the capacity enhancements achievable from deploying multiple h... more An investigation is performed into the capacity enhancements achievable from deploying multiple high altitude platforms (HAPs) arranged in different constellations but sharing common frequency bands and serving the same coverage area. Single and multiple cell configurations per HAP are examined. It is shown how overall system capacity may be increased, largely commensurate with the number of extra platforms deployed. This
2014 IEEE Globecom Workshops (GC Wkshps), 2014
IEE Seminar New Access Network Technologies, 2000
With an ever increasing demand for capacity for future generation multimedia applications, servic... more With an ever increasing demand for capacity for future generation multimedia applications, service providers are looking to utilise the frequency allocations in the millimetre wave bands, e.g. those specified for Local Multi-Point Distribution Systems (LMDS). In these frequency bands signals are attenuated by rain and line of sight paths are required. A possible solution to these effects is to use High Altitude Platforms (HAPs). HAPs are either airships or planes that operate in the stratosphere, 17-22km above the ground. Such platforms have the potential capability to serve a large number of users, using considerably less communications infrastructure than required by a terrestrial network. They can be considered as either a complimentary or disruptive technology -complementary in the sense that they augment existing infrastructure, or disruptive in the sense that they replace existing infrastructure.
Proceedings of the 5th International ICST Conference on Cognitive Radio Oriented Wireless Networks and Communications, 2010
Abstract We propose acognitive greedy-backhaul'(CGB) routing metric that ass... more Abstract We propose acognitive greedy-backhaul'(CGB) routing metric that associates routing with an appropriate channel assignment scheme to determine cognitive backhaul links. Those backhaul links are established in congested areas where higher capacities ...
Seamless Interconnection for Universal Services. Global Telecommunications Conference. GLOBECOM'99. (Cat. No.99CH37042), 1999
Abstract System level design considerations for high altitude aeronautical platforms operating in... more Abstract System level design considerations for high altitude aeronautical platforms operating in the LMDS band are examined. Propagation effects in the LMDS band are outlined, followed by a brief introduction to different platform scenarios. Ground-based and ...
Electronics & Communication Engineering Journal, 2001
Proceedings of 6th International Symposium on Personal, Indoor and Mobile Radio Communications, 1995
ABSTRACT
2010 IEEE 72nd Vehicular Technology Conference - Fall, 2010
ABSTRACT In this paper we propose a novel connection admission control scheme named Rate Transiti... more ABSTRACT In this paper we propose a novel connection admission control scheme named Rate Transition Area assisted Guaranteed Handover Scheme (GHS-RTA), which utilizes the geographical information, rate transition areas and overlap areas to intelligently decide when to block a new call. This scheme helps avoid possible inter-cell and intra-cell handover failures for HAP communications systems with adaptive modulation and coding in the physical layer. Simulation results show that the GHS-RTA can improve the average new call blocking probability greatly (by a minimum of 21.5% for the system model with the parameter values chosen) while maintaining zero inter-cell and intra-cell handover call dropping probabilities compared with Extended Time-based Channel Reservation Algorithm, and that the larger the rate transition area and the overlap area, the better the average new call blocking performance.
Several different distributed channel assignment algorithms are compared using Unsupervised FDMA ... more Several different distributed channel assignment algorithms are compared using Unsupervised FDMA (UFDMA), a multiple access scheme for the land mobile radio environment. All algorithms make use of coexistence etiquettes which allow different users to share common frequency allocation. It is found that using the Least Interfered Channel (LIC) with call reassignment provides considerably better performance than LIC, and LIC better than First Available (FA). A tight interference level threshold, at the transmitter, improves the performance of the FA algorithm, but it is much better to use a loose interference threshold with the LIC algorithms.
IWISPA 2000. Proceedings of the First International Workshop on Image and Signal Processing and Analysis. in conjunction with 22nd International Conference on Information Technology Interfaces. (IEEE Cat. No.00EX437), 2000
ABSTRACT
This paper explores an efficient Medium Access Control protocol for carrying data traffic via sat... more This paper explores an efficient Medium Access Control protocol for carrying data traffic via satellite. The Combined Free/Demand Assignment Multiple Access (CFDAMA) protocol combines free assignment of data slots with demand assignment, providing a minimum delay of one round trip time at low loads and the statistical multiplexing gains of demand assignment at high loads. The delay/utilisation performance of CFDAMA is explored for both Poisson and selfsimilar traffic models. It is shown for Poisson traffic that CFDAMA provides both extremely low end-to end delay and variance in delay of packet transmissions over a wide range of loads up to 85% of the channel capacity. For self-similar traffic, it has been found that the scheme is limited to a lower maximum channel loading, but performs better at low channel loads. The importance of an accurate traffic model in network performance evaluation is highlighted. Comparisons are made between CFDAMA and the Slotted ALOHA protocol, and it is shown that CFDAMA outperforms Slotted ALOHA over virtually the entire range of channel utilisation.
2006 International Conference on Wireless Communications, Networking and Mobile Computing, 2006
Abstract We measure and evaluate the capacity of an asymmetric multi-hop wireless ad hoc network ... more Abstract We measure and evaluate the capacity of an asymmetric multi-hop wireless ad hoc network from a new perspective using minimum impact routing, which selects a route based on total interference impact measured with total disturbed nodes along an asymmetrical ...
2012 International Symposium on Wireless Communication Systems (ISWCS), 2012
ABSTRACT This paper presents a novel Medium Access Control (MAC) protocol named ALOHA and Q-Learn... more ABSTRACT This paper presents a novel Medium Access Control (MAC) protocol named ALOHA and Q-Learning based MAC with Informed Receiving (ALOHA-QIR) for Wireless Sensor Networks (WSNs). This scheme is implemented by combining frame based Slotted ALOHA and Q-Learning. ALOHA based schemes have the benefits of simplicity, low computation and overheads, but suffer collisions from the blind transmission strategy. By considering the previous transmission experience, Q-Learning offers nodes certain intelligence to access slots with a lower probability of collision. During data transmissions, receivers are informed by transmitters about their future slot selections so that the receivers can turn off their radio in other slots to save energy. Compared with basic Slotted ALOHA, ALOHA-QIR obtains significant improvements in throughput, delay and energy efficiency.
Some services which are provided by satellite, or which may in future by provided by High-Altitud... more Some services which are provided by satellite, or which may in future by provided by High-Altitude Platform (HAP) networks, can be configured to tolerate short link outages without loss of service. If the shortest fades can be `bridged¿, this will reduce the failure rate of services. The two most common causes of outage in mm-wave links, which require line-of-sight propagation, direct from Satellites or High-Altitude Platforms (HAPs) to a moving train are heavy rain and tunnels. It is shown that ability to tolerate outages of up to 30 minutes enables the delivery of content at 99.9% availability in an extremely rainy location such as Singapore, a service which would otherwise not be possible. The improvements offered to services on trains by exploiting antenna site diversity and caching are also evaluated.
IET Conference on Wireless Sensor Systems (WSS 2012), 2012
ABSTRACT In this paper, an ALOHA based Medium Access Control (MAC) protocol (RL-ALOHA with Inform... more ABSTRACT In this paper, an ALOHA based Medium Access Control (MAC) protocol (RL-ALOHA with Informed Receiving) is proposed for multi-hop Wireless Sensor Networks (WSNs), which overcomes the traditional problems of low throughput, while exploiting their advantages of simplicity, low computational complexity and overheads. Reinforcement Learning (RL) is implemented as an intelligent slot assignment strategy in order to avoid collisions with minimal additional overheads. To improve the energy efficiency, Informed Receiving (IR) and ping packets are applied to avoid idle listening and overhearing. The simulation results show that this approach significantly increases the energy efficiency, achieves over twice throughput of Slotted ALOHA and reduces the end-to-end delay.
The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2002
Channel assignment strategies for use with a high altitude platform, spot beam architecture are e... more Channel assignment strategies for use with a high altitude platform, spot beam architecture are examined. A novel power roll-off approximation is derived to allow terrestrial simulation tools to be used, and simulation performance is compared with a theoretical lower bound derived from the Engset distribution. It is shown that the use of cell overlap considerably e nhances the blocking probability performance, in addition to boosting flexibility.
GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489), 2003
An investigation is performed into the capacity enhancements achievable from deploying multiple h... more An investigation is performed into the capacity enhancements achievable from deploying multiple high altitude platforms (HAPs) arranged in different constellations but sharing common frequency bands and serving the same coverage area. Single and multiple cell configurations per HAP are examined. It is shown how overall system capacity may be increased, largely commensurate with the number of extra platforms deployed. This
2014 IEEE Globecom Workshops (GC Wkshps), 2014
IEE Seminar New Access Network Technologies, 2000
With an ever increasing demand for capacity for future generation multimedia applications, servic... more With an ever increasing demand for capacity for future generation multimedia applications, service providers are looking to utilise the frequency allocations in the millimetre wave bands, e.g. those specified for Local Multi-Point Distribution Systems (LMDS). In these frequency bands signals are attenuated by rain and line of sight paths are required. A possible solution to these effects is to use High Altitude Platforms (HAPs). HAPs are either airships or planes that operate in the stratosphere, 17-22km above the ground. Such platforms have the potential capability to serve a large number of users, using considerably less communications infrastructure than required by a terrestrial network. They can be considered as either a complimentary or disruptive technology -complementary in the sense that they augment existing infrastructure, or disruptive in the sense that they replace existing infrastructure.
Proceedings of the 5th International ICST Conference on Cognitive Radio Oriented Wireless Networks and Communications, 2010
Abstract We propose acognitive greedy-backhaul'(CGB) routing metric that ass... more Abstract We propose acognitive greedy-backhaul'(CGB) routing metric that associates routing with an appropriate channel assignment scheme to determine cognitive backhaul links. Those backhaul links are established in congested areas where higher capacities ...
Seamless Interconnection for Universal Services. Global Telecommunications Conference. GLOBECOM'99. (Cat. No.99CH37042), 1999
Abstract System level design considerations for high altitude aeronautical platforms operating in... more Abstract System level design considerations for high altitude aeronautical platforms operating in the LMDS band are examined. Propagation effects in the LMDS band are outlined, followed by a brief introduction to different platform scenarios. Ground-based and ...
Electronics & Communication Engineering Journal, 2001
Proceedings of 6th International Symposium on Personal, Indoor and Mobile Radio Communications, 1995
ABSTRACT
2010 IEEE 72nd Vehicular Technology Conference - Fall, 2010
ABSTRACT In this paper we propose a novel connection admission control scheme named Rate Transiti... more ABSTRACT In this paper we propose a novel connection admission control scheme named Rate Transition Area assisted Guaranteed Handover Scheme (GHS-RTA), which utilizes the geographical information, rate transition areas and overlap areas to intelligently decide when to block a new call. This scheme helps avoid possible inter-cell and intra-cell handover failures for HAP communications systems with adaptive modulation and coding in the physical layer. Simulation results show that the GHS-RTA can improve the average new call blocking probability greatly (by a minimum of 21.5% for the system model with the parameter values chosen) while maintaining zero inter-cell and intra-cell handover call dropping probabilities compared with Extended Time-based Channel Reservation Algorithm, and that the larger the rate transition area and the overlap area, the better the average new call blocking performance.