On‐line wavelet filtering of narrowband noise in signal detection of spread spectrum system for location tracking

This research work introduces some novel techniques for interference-resilient OFDM wireless communication. Firstly, novel schemes for spatial multiplexing and interference cancelation based on signal subspace estimation are proposed. Secondly, the OFDM system is designed such that it meets three main objectives simultaneously, namely, (i) interference-resiliency, (ii) throughput maximization, and (iii) energy consumption minimization. Interference-cancelation techniques in prior art mostly consider maximization of throughput without any focus on energy consumption. On the other hand, the literature in energy minimization is limited to interference-free environments. Most of the previous techniques also have a drawback that they cannot operate in smart or dynamically changing interference environments. The focus here is on interference-resilient communication with equal attention to both throughput and energy-efficiency maximization in dynamic hostile environments. The optimization problem is formulated, and then optimal policies and switching thresholds are found for throughput and energy-efficient interference-resilient communication. Methodologies for estimating the channel and jammer conditions and then adapting the transmission strategies accordingly are proposed. Moreover, to have an effective defense against smart jamming scenario, a constant-payoff scheme is also introduced. Simulation results are compared with previous techniques that demonstrate the efficacy of proposed research.

Section: Technique Mitigation Approach Concernsmentioning

confidence: 99%

Novel schemes for interference‐resilient OFDM wireless communication

Imran

Loan

Mahmood

2015

“…In several signal processing applications, the boundaries of events and the transition between states indicating important features may be indicated through detection of edges [21][22][23][24][25][26][27][28]. If properly identified, these events can be used to infer the topology parameters of a given line.…”

Section: Serial To Bridge Tapmentioning

confidence: 99%

“…If properly identified, these events can be used to infer the topology parameters of a given line. In several signal processing applications, the boundaries of events and the transition between states indicating important features may be indicated through detection of edges [21][22][23][24][25][26][27][28]. Because r.t/ and h.t / are typically continuous and without eccentricities, edges can be detected as isolated singularities, which are points at which a given function is not defined, or it fails to be well-behaved in some particular way, such as differentiability or continuity.…”

Section: Serial To Bridge Tapmentioning

confidence: 99%

A wavelet‐based expert system for digital subscriber line topology identification

Lima

Klautau

Costa

et al. 2014

This work proposes a new method for automatically identifying topologies of lines with one or more sections in a telephone network. The method is based on the examination of both impulse response and time-domain reflectometry trace of a line under test. They are analyzed using a method based on the wavelet transform that identifies and extracts features that contain information about the line topology. Those features are interpreted by an expert system composed of three sequential modules that estimate, respectively, the type of line makeup (serial or bridge tap), the lengths of the line sections, and the corresponding cable type, which are the parameters that completely identify the topology according to the assumed model. A thorough comparison with two state-of-the-art methods is also presented using several twisted-pair copper cables. The results show that the proposed method provides good accuracy with respect to topology identification at low computational cost.

“…However, such techniques have drawback that the jammer can be effectively separated only if it is sufficiently stronger than desired signal. Popular time–frequency analysis techniques include time–frequency distribution such as spectrogram and Wigner–Ville distribution , bilinear time–frequency distributions , short‐time Fourier transform , wavelet transforms , and so on. Subspace processing techniques perform jammer excision.…”

Section: Literature Reviewmentioning

confidence: 99%

An energy‐efficient anti‐jam cognitive system for wireless OFDM communication

Imran

Loan

Mahmood

2013

SUMMARY In this paper, anti‐jamming capabilities are proposed for a generic OFDM‐based wireless communication system. The performance of a wireless system may severely degrade in presence of jamming or intentional interferences. A malicious entity can send strong interference or noisy signals in the same transmit frequency band thus preventing the intended receiver to correctly decode the transmitted data. As a countermeasure, our work proposes algorithms and techniques to restore the system performance in presence of such malicious entities. Proposed anti‐jamming system consists of an adaptive framework that adapts itself to varying jammer behavior and wireless environment, and then, it chooses an optimal strategy to effectively cancel out the effect of jamming and channel fading. Optimization problem is formulated as a multi‐objective criterion for maximization of system throughput and minimization of energy consumption. Simulation results computed in Rayleigh fading channels with different wideband jamming modes and powers show that the proposed system effectively cancels out the jamming and channel fading effects thus maximizing the system performance and minimizing cost of energy consumption. Copyright © 2013 John Wiley & Sons, Ltd.