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2012

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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 Dec 2012

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 …


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 Dec 2012

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 Dec 2012

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 Dec 2012

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 …