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Full-Text Articles in Engineering
Spectral-Efficiency Of Multi-Antenna Links In Ad-Hoc Networks With Limited Tx Csi, Siddhartan Govindasamy, Daniel Bliss, David Staelin
Spectral-Efficiency Of Multi-Antenna Links In Ad-Hoc Networks With Limited Tx Csi, Siddhartan Govindasamy, Daniel Bliss, David Staelin
Siddhartan Govindasamy
An asymptotic expression is derived for the mean spectral efficiency of multi-antenna links randomly distributed on a plane in a uniform manner where transmitters (Tx) have Channel-State-Information (CSI) of the channels between themselves and their target receivers while receivers (Rx) have CSI between themselves and all transmitters. The mean per-link spectral efficiency in the network is found to increase if nodes transmit using a subset of their strongest channel modes instead of the link-optimal strategy of water-filling on all channel modes (Farrokhi et al.). For reasonable parameters, this system which requires limited Tx CSI, has approximately double the mean spectral …
Spectral Efficiency In Single-Hop Ad-Hoc Wireless Networks With Interference Using Adaptive Antenna Arrays, Siddhartan Govindasamy, Daniel Bliss, David Staelin
Spectral Efficiency In Single-Hop Ad-Hoc Wireless Networks With Interference Using Adaptive Antenna Arrays, Siddhartan Govindasamy, Daniel Bliss, David Staelin
Siddhartan Govindasamy
Receivers with N antennas in single-hop, ad-hoc wireless networks with nodes randomly distributed on an infinite plane with uniform area density are studied. Transmitting nodes have single antennas and transmit simultaneously in the same frequency band with power P that decays with distance via the commonly-used inverse-polynomial model with path-loss-exponent (PLE) greater than 2. This model applies to shared spectrum systems where multiple links share the same frequency band. In the interference-limited regime, the average spectral efficiency of a representative link E[C] (b/s/Hz/link) is found to grow as log(N) and linearly with PLE, and its variance decays as 1/N. The …
Cdf Of The Spectral-Efficiency Of A Simple Distributed Channel Assignment Algorithm In Spatially Distributed Wireless Networks, Siddhartan Govindasamy, Raghu Rangan, Elena Koukina, Ashley Lloyd
Cdf Of The Spectral-Efficiency Of A Simple Distributed Channel Assignment Algorithm In Spatially Distributed Wireless Networks, Siddhartan Govindasamy, Raghu Rangan, Elena Koukina, Ashley Lloyd
Siddhartan Govindasamy
The Cumulative-Distribution-Function (CDF) of the spectral efficiency of links in spatially distributed networks with orthogonal channels and a simple channel assignment algorithm is presented for constant link-lengths and nearest-neighbor links. Transmitters are randomly distributed on the plane with uniform probability, and receivers are either randomly distributed or at hexagonal lattice sites. This result includes random channel assignments as a special case. The CDF is used to find the spectral efficiency for a given, small outage probability which is used to optimize the number of channels to maximize the spectral efficiency. The optimum number of channels represents the best trade off …
The Performance Of Linear Multiple-Antenna Receivers With Interferes Distributed On A Plane, Siddhartan Govindasamy, Filip Antic, Daniel Bliss, David Staelin
The Performance Of Linear Multiple-Antenna Receivers With Interferes Distributed On A Plane, Siddhartan Govindasamy, Filip Antic, Daniel Bliss, David Staelin
Siddhartan Govindasamy
We find an asymptotic expression for the average signal to interference ratio (SIR) between a transmitter with a single isotropic antenna and a multi-antenna linear receiver in the presence of interferers with single isotropic transmit antennas distributed uniformly on an infinite plane. The channels are modeled as complex Gaussian random variables with average received power dependent on the distance separating nodes. We find that in large networks, the average SIR for a representative link depends primarily on the ratio of the number of receive antenna elements to the area density of interferers. Furthermore for our network model, the SIR grows …
Linear Mmse Receivers For Random Cdma In Wireless Networks With Equal Transmit Powers, Siddhartan Govindasamy, David Staelin
Linear Mmse Receivers For Random Cdma In Wireless Networks With Equal Transmit Powers, Siddhartan Govindasamy, David Staelin
Siddhartan Govindasamy
The performance of single-hop links in ad-hoc wireless systems using direct-sequence (DS) code-division-multiple-access (CDMA) with random signature sequences and linear minimum-mean-square-error (MMSE) receivers is investigated. Expressions for the average signal-to-interference-plus-noise-ratio (SINR) and spectral efficiency (b s-1 Hz-1 link-1) were derived for a representative link in the presence of interferers distributed randomly on a plane with uniform area density p interferers m-2. Nodes transmit with equal power P, which decays with distance r as r-alpha. An expression for the optimum spreading factor given system parameters is also provided. It is found that for …
Spectral Efficiency Of Wireless Networks With Multi-Antenna Base Stations And Spatially Distributed Nodes, Siddhartan Govindasamy, Daniel Bliss, David Staelin
Spectral Efficiency Of Wireless Networks With Multi-Antenna Base Stations And Spatially Distributed Nodes, Siddhartan Govindasamy, Daniel Bliss, David Staelin
Siddhartan Govindasamy
We analyze networks with wireless nodes distributed randomly in space, transmitting simultaneously in the same channel to their nearest base-stations using a simple power control algorithm. Base-stations are on a hexagonal grid and have N optimally-phased antennas. We derive the asymptotic mean upstream spectral efficiency(validated by simulation) as a function of N, wireless-node density, base-station separation, and path-loss-exponent which controls signal attenuation with distance. These results indicate that mean per-link spectralefficiency is constant if the number of receive antennas or density of base-stations is increased linearly withwireless node density. They also improve our understanding of systems like city-wide wireless Internet …
Wispernet: Anti-Jamming For Wireless Sensor Networks, Miroslav Pajic, Rahul Mangharam
Wispernet: Anti-Jamming For Wireless Sensor Networks, Miroslav Pajic, Rahul Mangharam
Rahul Mangharam
Resilience to electromagnetic jamming and its avoidance are difficult problems. It is often both hard to distinguish malicious jamming from congestion in the broadcast regime and a challenge to conceal the activity patterns of the legitimate communication protocol from the jammer. In the context of energy-constrained wireless sensor networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This results in well-defined communication patterns with possibly predictable intervals of activity that are easily detected and jammed by a statistical jammer. We present an anti-jamming protocol for sensor networks which eliminates spatio-temporal patterns …
Anti-Jamming For Embedded Wireless Networks, Miroslav Pajic, Rahul Mangharam
Anti-Jamming For Embedded Wireless Networks, Miroslav Pajic, Rahul Mangharam
Rahul Mangharam
Resilience to electromagnetic jamming and its avoidance are difficult problems. It is often both hard to distinguish malicious jamming from congestion in the broadcast regime and a challenge to conceal the activity patterns of the legitimate communication protocol from the jammer. In the context of energy-constrained wireless sensor networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This results in well-defined communication patterns with possibly predictable intervals of activity that are easily detected and jammed by a statistical jammer. We present an anti-jamming protocol for sensor networks which eliminates spatio-temporal patterns …
Embedded Virtual Machines For Robust Wireless Control And Actuation, Miroslav Pajic, Rahul Mangharam
Embedded Virtual Machines For Robust Wireless Control And Actuation, Miroslav Pajic, Rahul Mangharam
Rahul Mangharam
Embedded wireless networks have largely focused on open-loop sensing and monitoring. To address actuation in closed-loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. As the links, nodes and topology of wireless systems are inherently unreliable, such time-critical and safety-critical applications require programming abstractions and runtime systems where the tasks are assigned to the sensors, actuators and controllers as a single component rather than statically mapping a set of tasks to a specific physical node at design time. To this end, we introduce the Embedded Virtual Machine (EVM), …
A Unified Wireless Sensor Network Framework, Joshua Kiepert, Sin Ming Loo
A Unified Wireless Sensor Network Framework, Joshua Kiepert, Sin Ming Loo
Electrical and Computer Engineering Faculty Publications and Presentations
Wireless sensor networks (WSNs) have been a significant area of research over the past decade. WSN systems are used in a wide range of applications such as surveillance, environmental monitoring, target tracking, wildlife tracking, personal health monitoring, machinery monitoring, and many others. With such wide ranging applications, there is active research in nearly every facet of the field including network topologies, communication protocols, node localization, time synchronization, and sensor data processing. This movement has largely been the result of the advances in microelectronics and low-power radio systems. These advancements have enabled the design and implementation of small, powerful, low-power, wireless …