Ad-hoc wireless sensor networks
Research Area:
Research Lines:
Research Lines:
Research
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Start date: 2005-01-01
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Project abstract
An ad hoc wireless sensors network (refer, for example to, IEEE 802.15 standard compliant WPAN networks) is a collection of wireless mobile nodes that self-configure to form a network without the aid of any established infrastructure.
Without an inherent infrastructure, the mobiles handle the necessary control and networking tasks by themselves, generally through the use of distributed control algorithms. Multihop connections, whereby intermediate nodes send the packets toward their final destination, are supported to allow for efficient wireless communication between terminals that are relatively far apart. Ad hoc wireless networks are nowadays highly appealing because: they can be rapidly deployed, reconfigured and tailored to specific applications, moreover they are also highly robust due to their distributed nature, node redundancy, and the lack of single points of failure.
Some of the most exciting applications for ad hoc wireless networks are the energy-constrained category. Devices with rechargeable batteries must conserve energy to maximize time between recharging. Of particular interest are devices that cannot be recharged, that is, sensors that are embedded in walls or dropped into a remote region. In this context lifetime maximization becomes a key point that needs to be addressed at all layers of communication systems, from hardware to network layer and application. This entails interesting energy trade-offs across protocol layers. It has been recently shown that channel fluctuations of the wireless links between each terminal of the network may be exploited in order to increase the system efficiency by taking advantage of node cooperation. As a consequence, a multiple (virtual) antenna system may be designed by means of cooperating nodes so as to perform a distributed space-time coding algorithm. Performance analysis for cooperative systems in different channel conditions will be carried out. Opportunistic scheduling strategies will also be considered. Finally, with the aim of minimizing the overall energy consumption and thus maximizing the network lifetime, optimal routing algorithms will be designed based on the knowledge of both node positions in the network and of residual battery life. The project focuses in particular on the IEEE 802.16 and IEEE 802.15.4 standard that allows cooperative transmission techniques to be employed at the MAC and PHY layer, performance analysis and design of cooperative transmitting systems will be investigated for MESH IEEE 802.16 and IEEE 802.15.4 complaint networks.
Without an inherent infrastructure, the mobiles handle the necessary control and networking tasks by themselves, generally through the use of distributed control algorithms. Multihop connections, whereby intermediate nodes send the packets toward their final destination, are supported to allow for efficient wireless communication between terminals that are relatively far apart. Ad hoc wireless networks are nowadays highly appealing because: they can be rapidly deployed, reconfigured and tailored to specific applications, moreover they are also highly robust due to their distributed nature, node redundancy, and the lack of single points of failure.
Some of the most exciting applications for ad hoc wireless networks are the energy-constrained category. Devices with rechargeable batteries must conserve energy to maximize time between recharging. Of particular interest are devices that cannot be recharged, that is, sensors that are embedded in walls or dropped into a remote region. In this context lifetime maximization becomes a key point that needs to be addressed at all layers of communication systems, from hardware to network layer and application. This entails interesting energy trade-offs across protocol layers. It has been recently shown that channel fluctuations of the wireless links between each terminal of the network may be exploited in order to increase the system efficiency by taking advantage of node cooperation. As a consequence, a multiple (virtual) antenna system may be designed by means of cooperating nodes so as to perform a distributed space-time coding algorithm. Performance analysis for cooperative systems in different channel conditions will be carried out. Opportunistic scheduling strategies will also be considered. Finally, with the aim of minimizing the overall energy consumption and thus maximizing the network lifetime, optimal routing algorithms will be designed based on the knowledge of both node positions in the network and of residual battery life. The project focuses in particular on the IEEE 802.16 and IEEE 802.15.4 standard that allows cooperative transmission techniques to be employed at the MAC and PHY layer, performance analysis and design of cooperative transmitting systems will be investigated for MESH IEEE 802.16 and IEEE 802.15.4 complaint networks.
Project results
Transmission strategies are proposed so as to exploit the benefits of diversity reception. Differently form conventional point to point communications, cooperative transmission schemes allows different users or nodes in a wireless network to share resources to create collaboration through distributed transmission where each user’s information is sent out not only by the user, but also by collaborating users. The goal of this scheme is to exploit a new form of space diversity to combat the effects of channel impairments due to fading, the latter has been termed cooperative diversity. Results show that the joint exploitation of multi-hopping techniques together with node cooperation (at MAC – Medium Access Control - and physical layer) lead to valuable benefits in reducing complexity of routing problems. Moreover radio localization techniques are developed based on delay and/or received power (RSSI) measurements. Tracking of terminal positions for mobile users is also dealt with. Publications:
- C. Morelli, M. Nicoli, V. Rampa, U. Spagnolini, C. Alippi, “Particle filters for RSS-based localization in wireless sensor networks: an experimental study”, Proc. IEEE ICASSP 2006, May 2006.
- S.Savazzi and U. Spagnolini, “Energy Aware Power Allocation Strategies for Multihop-Cooperative Transmission Schemes,” Conference on Information Sciences and Systems CISS-IEEE, 2006.
- A. del Coso, S.Savazzi, U. Spagnolini and C. Ibars, “VIRTUAL MIMO CHANNELS IN COOPERATIVE MULTIHOP WIRELESS SENSOR NETWORKS,” Conference on Information Sciences and Systems CISS-IEEE, 2006.
- C. Galli, S. Savazzi and U. Spagnolini, “A MULTIHOP-COOPERATIVE TRANSMISSION PROTOCOL FOR ENERGY-LIMITED WPAN SYSTEMS,” 6TH Scandinavian Workshop on Wireless Ad hoc networks, Stockholm, 3-4 May 2006.
- M. Cremaschi, O. Simeone and U. Spagnolini, “Distributed timing synchronization for sensor networks with coupled discrete-time oscillators”, to appear in Proc. International Workshop on Wireless Ad Hoc and Sensor Networks 2006.
- O. Simeone and U. Spagnolini, “Capacity region of wireless ad hoc networks using opportunistic collaborative communications”, to appear in Proc. IEEE International Conference on Communications, 2006.
- N. Varanese, O. Simeone, Y. Bar-Ness and U. Spagnolini, “A power allocation strategy for multi-antenna amplify-and-forward fading relay channels”, Proc. Conference on Information Sciences and Systems, 2006.
- N. Varanese, O. Simeone, Y. Bar-Ness and U. Spagnolini “Achievable rates of multi-hop and cooperative MIMO Amplify-and-Forward relay systems with full CSI”, to appear in IEEE Signal Processing Advances on Wireless Communications, 2006.
- O. Simeone, O. Somekh, Y. Bar-Ness and U. Spagnolini “Information theoretic analysis of multicell decoding and Amplify-and-Forward cooperation between mobiles for TDMA cellular systems,” Proc. Conference on Information Sciences and Systems, 2006.
- O. Simeone, O. Somekh, Y. Bar-Ness and U. Spagnolini, “Throughput of low power cellular systems with collaboration at base stations and mobiles”, MSRI Workshop on Mathematics of Relaying and Cooperation in Communication Networks, 2006.
- S. Savazzi and U. Spagnolini, “ENERGY AWARE POWER ALLOCATION STRATEGIES FOR MULTIHOP-COOPERATIVE TRANSMISSION SCHEMES,” submitted.
- S. Savazzi and U. Spagnolini, “DESIGN OF DISTRIBUTED RANDOMIZED ORTHOGONAL SPACE-TIME CODING SCHEMES FOR COOPERATIVE COMMUNICATION,” submitted.
- O. Simeone and U. Spagnolini, “Capacity of wireless ad hoc networks using opportunistic collaborative communications,” submitted.
- O. Simeone O. Somekh, Y. Bar-Ness and U. Spagnolini, “Uplink throughput of TDMA cellular systems with multicell processing and Amplify-and-Forward cooperation between mobiles”, submitted.
- O. Simeone, O. Somekh, Y. Bar-Ness and U. Spagnolini, “Throughput of low-power TDMA cellular systems with collaborative decoding at the base stations and cooperative transmission between mobiles”, submitted.
