Dr. Asis Nasipuri

Electrical and Computer Engineering

 


Research

My research interests are focused on design and development of network protocols and algorithms for multihop wireless networks, which include wireless sensor networks, wireless mesh networks, and mobile ad hoc networks.

 

Current areas of interest:

  • Rechargeable Wireless Sensor Networks: This project addresses strategies for achieving continuous and long-term operations of wireless sensor networks that are powered by energy harvested from renewable energy sources, such as solar. In such networks, the energy resources available at the sensor nodes varies significantly from node to node and also over time. The objective of this research is to design networking protocols that control the energy consumption at the nodes to adapt to such spatial and temporal variations of energy resources. Key components of this research include:

    • Development of energy availability models for rechargeable networks: this involves energy source prediction and energy storage modeling.

    • Development of adaptive networking protocols that allow variable energy consumption: we are exploring joint power control and routing protocols, multi-channel routing protocols, adaptive duty-cycling, and event-based sampling schemes.

    • Intermittently connected networks: we are exploring cooperative data forwarding schemes for minimizing the delay in rechargeable networks that are characterized by frequent node outages.

  • Quality aware routing protocols for wireless mesh networks: We are exploring quality aware routing protocols and multichannel MAC for wireless mesh networks. Our current research involves the following topics

    • Design of effective quality based route quality metrics

    • Joint channel selection and routing schemes

    • Anycast routing protocols

  • Experimental research on sustainability of large scale wireless sensor networks: We are working on a collaborative research project with the Electric Power Research Institute (EPRI) to design and deploy WSNs for a number of monitoring applications in power generation stations and substations. Some of the components of this research project include:

    • Development of energy-efficient applications for monitoring the health of high voltage equipment in power substations and power plants

    • Load and energy aware routing

    • Beacon assisted self-localization schemes

    • Adaptive networking and signal processing schemes that enable the nodes to adapt to unpredictable spatial and temporal variations of energy resources that are caused by fluctuations of harvestable environmental energy at the node locations.

Other recent areas of interest:

  • Multi-channel medium access control (MAC) protocols for mobile ad hoc networks: We developed MAC protocols that employ dynamic channel selection mechanisms to improve the throughput in mobile ad hoc networks using the same aggregate resources, i.e. the same overall channel bandwidth and a single radio interface performing channel switching.

  • Multipath routing in mobile ad hoc networks: We developed on demand routing protocols for systematically determining and maintaining multiple alternate routes so that the frequency of route discoveries is dramatically reduced for re-establishment of routes during link breakages.

  • Protocols for directional antennas in mobile ad hoc networks: We developed MAC protocols that are based on practical adaptations of the IEEE 802.11 MAC to incorporate appropriate selection of the antenna directions for packet transmissions and receptions. The proposed MAC protocols provide higher throughput and lower average power consumption in the network. In addition, we developed an on-demand routing protocol using directional antennas that reduces the spread of routing packets by using directional transmissions.

  • Algorithms for resource constrained wireless sensor networks: We developed a number of novel energy-efficient algorithms for low-lower power wireless sensor networks. This includes:

    • GPS-free localization using an angle-of arrival estimation technique

    • Multi-sensor collaboration schemes using contour detection for spatio-temporal monitoring of slowly-varying signals

    • Serial data fusion scheme for the detection of weak signals