802.11 wireless LANs for broadband wireless access constitute a growing success story. Their deployment in single-cell (i.e. single AP) scenarios (homes, small business and hotspots) is well-supported by current .11 technology. However scaling such networks to the enterprise environment to serve a large number of simultaneous users with voice and data services while providing coverage remains a challenge. A promising architectural solution consists of a two-tier multi-cellular, multi-hop approach to WLAN network design whereby an AP mesh provides the infrastructure for communication between mobile clients. Implicit in this is a direct wireless inter-connection between mesh nodes which all route traffic (only some of which are APs with associated clients, and a very small fraction act as gateways to the wired Internet).
Our research seeks to advance the state-of-art of such .11 based multi-hop mesh networks by undertaking an integrated cross-layer approach to innovations at Layers 1-3 (joint PHY/MAC/Network). Optimizing of such networks will require on-line tuning of key protocol parameters at various layers (hence leading to an Adaptive Mesh). Currently we are investigating
Our approach combines protocol/algorithmic innovation supported by OPNET and NS3 simulations and experimental results from a StarEast based MESH network in a laboratory setting.
For more information check http://commnet.ee.washington.edu/funlab/
Underwater Acoustic Networking
Lead: Nathan Parrish, Leonard Tracy
Underwater acoustics has been a topic of research for decades. However, the idea of deploying networked teams of underwater vehicles for both deep and shallow water ocean exploration is a more recent topic of interest. The Seaglider, developed at the University of Washington, is one such vehicle. FUNLab along with the Applied Physics Lab (APL) are exploring physical and MAC layer protocols to provide robust, low power, efficient networking solutions to the Seaglider.
The underwater acoustic channel has properties that make it a very difficult medium for communications. For instance, the long propagation delay of sound, multi-path spread of the medium, frequency selective attenuation, shadowing zones, and other factors make this channel extremely hard to characterize. A commonly used approach for determining the acoustic propagation of sound in the underwater channel is to use ray tracing techniques based on Snell's Law. Members of the FUNLab are investigating ways to statistically characterize the underwater channel using techniques similar.
MAC protocols in the underwater environment must be designed with different considerations than those in the terrestrial environment. The long propagation delays of sound make carrier sensing and acknowledgment packets impractical. Additionally, autonomous underwater vehicles (AUVs) are extremely energy-constrained. These and other design considerations, including the lack of position information from GPS, necessitates new MAC design for AUV deployment, which is also an ongoing topic of research between the FUNLab and the APL.
For more information see the UAN Projects page
ns-3: Next Generation Open Source Network Simulator
Principal Investigators: Tom Henderson (Boeing), Sumit Roy (UW), George Riley (Georgia Tech) and Sally Floyd (ICSI, UC Berkeley) Contributor: Ilango Purushothaman(UW)
ns-2 is a discrete-event network simulator that is being used extensively in network research circles. It has been funded by a number of previous research projects, but none directly as an infrastructure project since 2000. A clear need exists for additional focused development work to occur on ns. The ns-3 project seeks to do just that and is the next major revision of the ns-2 simulator.
ns-3 is a managed software development program to comprehensively re-design, enhance and maintain the popular ns-2, to address research and educational challenges for next generation of data networks. This four-year project will
i) refactor the simulator's architecture
ii) develop new networking protocol models for wireless
iii) provide new opportunities for software encapsulation, and
iv) integrate the tool with virtual network testbeds.
For details on this project, check http://www.nsnam.org/.