http://www.eecs.ucf.edu/~dcm/Teaching/COT4810-Spring2011/Literature/SensorNetworksSurvey.pdf

Wireless sensor networks: a survey

The advancement in wireless communications and electronics has enabled the development of low-cost sensor networks. The sensor networks can be used for various application areas (e.g., health, military, home). For different application areas, there are different technical issues that researchers are currently resolving. The current state of the art of sensor networks is captured in this article, where solutions are discussed under their related protocol stack layer sections. This article also points out the open research issues and intends to spark new interests and developments in this field.

/pdf/a-survey-on-sensor-networks-5beav0ez6k.pdf

A survey on sensor networks

Wireless Communications

Alhussein Abouzeid Rensselaer Polytechnic Institute Raviraj Adve University of Toronto Dharma Agrawal University of Cincinnati Walid Ahmed Tyco M/A-COM Sonia Aissa University of Quebec, INRSEMT Huseyin Arslan University of South Florida Nallanathan Arumugam National University of Singapore Saewoong Bahk Seoul National University Claus Bauer Dolby Laboratories Brahim Bensaou Hong Kong University of Science and Technology Rick Blum Lehigh University Michael Buehrer Virginia Tech Antonio Capone Politecnico di Milano Javier Gómez Castellanos National University of Mexico Claude Castelluccia INRIA Henry Chan The Hong Kong Polytechnic University Ajit Chaturvedi Indian Institute of Technology Kanpur Jyh-Cheng Chen National Tsing Hua University Yong Huat Chew Institute for Infocomm Research Tricia Chigan Michigan Tech Dong-Ho Cho Korea Advanced Institute of Science and Tech. Jinho Choi University of New South Wales Carlos Cordeiro Philips Research USA Laurie Cuthbert Queen Mary University of London Arek Dadej University of South Australia Sajal Das University of Texas at Arlington Franco Davoli DIST University of Genoa Xiaodai Dong, University of Alberta Hassan El-sallabi Helsinki University of Technology Ozgur Ercetin Sabanci University Elza Erkip Polytechnic University Romano Fantacci University of Florence Frank Fitzek Aalborg University Mario Freire University of Beira Interior Vincent Gaudet University of Alberta Jairo Gutierrez University of Auckland Michael Hadjitheodosiou University of Maryland Zhu Han University of Maryland College Park Christian Hartmann Technische Universitat Munchen Hossam Hassanein Queen's University Soong Boon Hee Nanyang Technological University Paul Ho Simon Fraser University Antonio Iera University "Mediterranea" of Reggio Calabria Markku Juntti University of Oulu Stefan Kaiser DoCoMo Euro-Labs Nei Kato Tohoku University Dongkyun Kim Kyungpook National University Ryuji Kohno Yokohama National University Bhaskar Krishnamachari University of Southern California Giridhar Krishnamurthy Indian Institute of Technology Madras Lutz Lampe University of British Columbia Bjorn Landfeldt The University of Sydney Peter Langendoerfer IHP Microelectronics Technologies Eddie Law Ryerson University in Toronto

Wireless communications

We present Greedy Perimeter Stateless Routing (GPSR), a novel routing protocol for wireless datagram networks that uses the positions of routers and a packet's destination to make packet forwarding decisions. GPSR makes greedy forwarding decisions using only information about a router's immediate neighbors in the network topology. When a packet reaches a region where greedy forwarding is impossible, the algorithm recovers by routing around the perimeter of the region. By keeping state only about the local topology, GPSR scales better in per-router state than shortest-path and ad-hoc routing protocols as the number of network destinations increases. Under mobility's frequent topology changes, GPSR can use local topology information to find correct new routes quickly. We describe the GPSR protocol, and use extensive simulation of mobile wireless networks to compare its performance with that of Dynamic Source Routing. Our simulations demonstrate GPSR's scalability on densely deployed wireless networks.

/pdf/gpsr-greedy-perimeter-stateless-routing-for-wireless-59gz21qf8y.pdf

GPSR: greedy perimeter stateless routing for wireless networks

The modal group delays (GDs) are a key property governing the dispersion of signals propagating in a multimode fiber (MMF). An MMF is in the strong-coupling regime when the total length of the MMF is much greater than the correlation length over which local principal modes can be considered constant. In this regime, the GDs can be described as the eigenvalues of zero-trace Gaussian unitary ensemble, and the probability density function (pdf) of the GDs is the eigenvalue distribution of the ensemble. For fibers with two to seven modes, the marginal pdf of the GDs is derived analytically. For fibers with a large number of modes, this pdf is shown to approach a semicircle distribution. In the strong-coupling regime, the delay spread is proportional to the square root of the number of independent sections, or the square root of the overall fiber length.

/pdf/statistics-of-group-delays-in-multimode-fiber-with-strong-43q1q1u2tz.pdf

Statistics of Group Delays in Multimode Fiber With Strong Mode Coupling

In multimode fiber transmission systems, mode-dependent loss and gain (collectively referred to as MDL) pose fundamental performance limitations. In the regime of strong mode coupling, the statistics of MDL (expressed in decibels or log power gain units) can be described by the eigenvalue distribution of zero-trace Gaussian unitary ensemble in the small-MDL region that is expected to be of interest for practical long-haul transmission. Information-theoretic channel capacities of mode-division-multiplexed systems in the presence of MDL are studied, including average and outage capacities, with and without channel state information.

/pdf/mode-dependent-loss-and-gain-statistics-and-effect-on-mode-3ycmn4quji.pdf

Mode-dependent loss and gain: statistics and effect on mode-division multiplexing.

Limits of orbital-angular-momentum multiplexing for free-space optical communication are revealed. Increasing the information capacity per unit bandwidth has been a perennial goal of scientists and engineers1. Multiplexing of independent degrees of freedom, such as wavelength, polarization and more recently space, has been a preferred method to increase capacity2,3 in both radiofrequency and optical communication. Orbital angular momentum, a physical property of electromagnetic waves discovered recently4, has been proposed as a new degree of freedom for multiplexing to achieve capacity beyond conventional multiplexing techniques5,6,7,8,9, and has generated widespread and significant interest in the scientific community10,11,12,13,14. However, the capacity of orbital angular momentum multiplexing has not been established or compared to other multiplexing techniques. Here, we show that orbital angular momentum multiplexing is not an optimal technique for realizing the capacity limits of a free-space communication channel15,16,17 and is outperformed by both conventional line-of-sight multi-input multi-output transmission and spatial-mode multiplexing.

/pdf/capacity-limits-of-spatially-multiplexed-free-space-4hl7evddz1.pdf

Capacity limits of spatially multiplexed free-space communication

We examine the use of differential pulse-position modulation (DPPM) for optical communication systems using intensity modulation with direct detection in the presence of additive white Gaussian noise. We present expressions for the error probability and power spectral density of DPPM. We show that for a given bandwidth, DPPM requires significantly less average power than pulse position modulation (PPM). We also examine the performance of DPPM in the presence of multipath intersymbol interference (ISI). We find that the ISI penalties incurred by PPM and DPPM exhibit very similar dependencies upon the channel RMS delay spread. We discuss the use of chip-rate and multichip-rate equalization to combat ISI. Finally, we describe potential problems caused by the nonuniform bit-rate characteristic of DPPM, and we propose several solutions.

/pdf/differential-pulse-position-modulation-for-power-efficient-4fzwoscazc.pdf

Differential pulse-position modulation for power-efficient optical communication

A 16 mm/sup 3/ autonomous solar-powered sensor node with bidirectional optical communication for distributed sensor networks has been demonstrated. The device digitizes integrated sensor signals and transmits/receives data over a free-space optical link. The system consists of three die - a 0.25 /spl mu/m CMOS ASIC, a 2.6 mm/sup 2/ SOI solar cell array, and a micromachined four-quadrant corner-cube retroreflector (CCR), allowing it to be used in a one-to-many network configuration. The CMOS ASIC includes a photosensor integrated 3 MHz oscillator, 69 pJ/bit optical receiver and 31 pJ/sample ADC.

/pdf/an-autonomous-16-mm-sup-3-solar-powered-node-for-distributed-4xv603f9n0.pdf

Joseph M. Kahn

Papers

Statistics of Group Delays in Multimode Fiber With Strong Mode Coupling

Mode-dependent loss and gain: statistics and effect on mode-division multiplexing.

Capacity limits of spatially multiplexed free-space communication

Differential pulse-position modulation for power-efficient optical communication

An autonomous 16 mm/sup 3/ solar-powered node for distributed wireless sensor networks