Showing papers by "Rahul C. Shah published in 2001"

Design methodology for PicoRadio networks

Abstract: One of the most compelling challenges of the next decade is the "last-meter" problem, extending the expanding data network into end-user data-collection and monitoring devices. PicoRadio supports the assembly of an ad hoc wireless network of self-contained mesoscale, low-cost, low-energy sensor and monitor nodes. While technology advances have made it conceivable to deploy wireless networks of heterogeneous nodes, the design of a low-power, low-cost, adaptive node in a reduced time to market is still a challenge. We present a design methodology for PicoRadio Networks, from system conception and optimization to silicon platform implementation. For each phase of the design, we demonstrate the applicability of our methodology through promising experimental results.

An ultra-low power and distributed access protocol for broadband wireless sensor networks

Abstract: An ultra-low power access control scheme has been proposed for broadband wireless sensor networks. This is a distributed method, which does not require the existence of a central base station, eliminating the possibility of a single point failure. This access protocol combines the best of simple carrier sense multiple access (CSMA) and spread spectrum techniques. It trades the bandwidth in broadband applications for higher power efficiency and throughput. Compared with other access schemes, it consumes far less power. This access protocol does not require a dedicated control channel, or synchronization, whether global or local. Additionally, it has very low delay and does not have the problem of coordinating broadcast and scheduled unicasts. For sensor network s, the inherent redundancy can be exploited to further improve power efficiency. It achieves much higher power efficiency than much more complicated algorithms seeking to reduce the redundancy.

Data link layer design for wireless sensor networks

Abstract: This paper presents the architecture of data link layer for wireless sensor networks. Requirements are specified and the functional description is given. The relationship between different subsystems is also discussed. The designed data link layer has ultra-low power consumption. It is distributed, simple and robust. Additionally, it requires no synchronization.

Content distribution architecture using network layer anycast

Abstract: Server replication is a common technique for distributing content efficiently and in a scalable manner to many clients. Directing clients to the "best" of these content-equivalent servers is a non-trivial problem. As a solution, we propose CDAA (Content Distribution Architecture using Anycast) that uses replicated servers and leverages the idea of anycast, supported at the network layer, to direct clients. CDAA assigns the same anycast address to content-equivalent servers and tracks the load on each of them. This information is used to direct clients in the network to the "best" server, improving user satisfaction by reducing the response time seen by the clients. CDAA is scalable, incrementally deployable and transparent to existing network applications and protocols. These objectives are achieved with minimal bandwidth overhead and computing requirements. Though the DNS (Domain Name System) and client software require some modifications, the routers and servers remain unchanged. We also present simulation results that demonstrate the efficacy of our architecture.