Magda El Zarki Ne X tworking’03 June 23-25,2003, Chania, Crete, Greece The First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN N ETWORKING 1 UWB Technology and Sensor Area Networks (SANs) Magda El Zarki and Vipin Mehta School of ICS, Dept. of CS UC, Irvine

Magda El Zarki Ne X tworking’03 June 23-25,2003, Chania, Crete, Greece The First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN N ETWORKING 2 SANs for Civil Infrastructures Understanding the environment: Mostly Fixed - no or low mobility Dense networks of Heterogeneous sensors –1000s of low cost sensors: 6” - 10’ apart, –tens of high end sensors: 10m - 30m Easy to deploy - cost effective, work with existing structures Low maintenance Scalable - progressive deployment over time Local processing and filtering of data Selective querying

Magda El Zarki Ne X tworking’03 June 23-25,2003, Chania, Crete, Greece The First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN N ETWORKING 3 Design Challenges Heterogeneity of sensors - strain, temperature, humidity, video – different data collection capabilities – different types of data Data transmission needs – periodic, threshold triggered, query based, time sensitive No Line of sight – embedded in concrete, in remote spaces, behind beams Power supply, longevity - grid, battery, self powered Scalability - progressive growth Robustness - survive link and node losses Self Healing - re-configuration of the system due to losses/additions Deployment - grid based, arbitrary/random, specific angle

Magda El Zarki Ne X tworking’03 June 23-25,2003, Chania, Crete, Greece The First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN N ETWORKING 4 Available Technologies Wired solutions - star, mesh, rings, etc. Wireless solutions –Cellular network –IEEE a/b/g –UC Berkeley Mote project –UCLA environmental sensor project –Bluetooth Current technologies do not provide the “desired” set of features for a SAN

Magda El Zarki Ne X tworking’03 June 23-25,2003, Chania, Crete, Greece The First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN N ETWORKING 5 Ultra Wide Band (UWB) Most current UWB systems are based on signals using narrow time domain impulses transmitted with the aid of time-hopping spread spectrum techniques or position modulation (referred to as impulse radio (IR) systems). In UWB, a signal is transmitted with a bandwidth much larger than the data modulation bandwidth and thus with a reduced power spectral density. IR systems produce a signal that is more covert, and has higher immunity to interference effects.

Magda El Zarki Ne X tworking’03 June 23-25,2003, Chania, Crete, Greece The First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN N ETWORKING 6 More on UWB Technology IR systems operate in the lowest possible frequency band that supports its wide transmission bandwidth –Which means that this radio has the best chance of penetrating materials that tend to be more opaque at higher frequencies. The use of signals with gigahertz bandwidths means that multipath is resolvable down to path differential delays on the order of a foot or less. –This significantly reduces fading effects –Allows low transmission power operation

Magda El Zarki Ne X tworking’03 June 23-25,2003, Chania, Crete, Greece The First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN N ETWORKING 7 More … UWB systems are flexible in terms of trading off throughput for range –E.g., the communication range can be varied accordingly to cover an area more optimally. This can be used for adaptive configuration of the sensor nodes based on their proximity to a root/central node. The nodes closer to the root will have relatively more aggregated data while the ones further away from the root have less of it. Position Location Capability –short impulse allows for accurate delay estimates, which can be used for accurate position location.

Magda El Zarki Ne X tworking’03 June 23-25,2003, Chania, Crete, Greece The First COST-IST(EU)-NSF(USA) Workshop on EXCHANGES & TRENDS IN N ETWORKING 8 Conclusions UWB is a promising technology for sensor network applications because of its many desirable features Need to design a MAC that makes use of the unique features that UWB offers us for an efficient SAN design and that has hooks for cross layer operation