Download or read book Interference Mitigation in Frequency Hopping Ad Hoc Networks written by Jens Elsner and published by . This book was released on 2012 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Fairness Oriented Interference Balancing Scheme for Cooperative Frequency Hopping Ad Hoc Networks written by Xavier Pujol i Molist and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: English: It may quite frequently occur in an ad hoc network that the density of users in a given area becomes relatively high during some period of time. At the same time, network resource scheduling is not done regarding these moments with a higher load, but it is done according to average parameters of the network in order to have a trade-off solution that reaches the highest possible quality of service (QoS) while keeping the assigned resources for it as close to be fully exploited as possible. As a result, it may happen that the number of users in a network willing to transmit information is higher than the available resources in that network. On the other hand, in ad hoc networks, the frequency hopping spread spectrum (FHSS) multiple access technique is widely used in the radio interface. In FHSS, the total available bandwidth is partitioned into a certain number of frequency channels having the same bandwidth. In time domain, there is also a division into time intervals. This thesis is focused on the case in which the time intervals have the same duration, called hop period, and specifically on the case where the hop periods for all transmitters are synchronous. Then, in every hop period, every transmitter is been assigned some of those channels to transmit. It means that every transmitter will transmit through some frequency channels, and after the hop period, the transmission will hop into some other channels; and this will happen recursively after every hop period. When, in every hop period, every assigned frequency channel has been assigned to one (and no more) transmitter, then, there is orthogonality among users or, in other words, the hopping sequences or codes, according to which channels are assigned to each user in every hop, are orthogonal. When the hopping sequences are orthogonal, there is no interference among the users of the system because no transmitter coincides with any other in the same frequency channel at the same time (namely, there are no collisions). Orthogonality can always hold when the number of transmitters is less or equal to the number of available frequency channels in the FHSS system. However, when this condition is no longer satisfied, i.e., when there are more transmitters that may simultaneously transmit than available frequency channels, orthogonality is no longer preserved and, so, interference occurs unavoidably. The interference distribution among users depends on the design of the hopping sequences. With conventional approaches for designing the hopping sequences, interference is extremly unbalanced across all users and so, a completely unfair scenario takes place. This work tackles this problem and proposes a method for designing frequency hopping sequences that achieve at the same time a fair interference allocation across all users and an optimal interference reduction. The proposed scheme is optimal in terms of interference level because the overall number of collisions that take place in every hop is the minimum possible. At the same time, this fairness-oriented approach distributes the collisions among nodes in such a way that the variance of the interference power seen by the nodes is considerably reduced. Thereby, this scheme achieves a much more equitable interference balancing across the nodes. The results displayed by the fairness-oriented scheme in terms of fairness are much better than those ones displayed by the two reference studied schemes for both slow and fast frequency hopping.

Download or read book Co channel Interference Mitigation for Robust Coexistence of Frequency Hopped Networks written by and published by . This book was released on 2006 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: To meet the military's increased need for rapidly deployable communication solutions, wireless networks are becoming increasingly common within tactical environments. Frequency hopping (FH) is widely used for radio transmission in such networks due to its low probability of detection/interception. With the increasing deployment, multiple networks occupying overlapping frequency bands are likely to coexist in a physical environment, especially in tactical operations, emergency situations, or dense-populated areas. Consequently co-channel interference due to frequency collisions can become a major performance limiting factor. In this project, we developed a novel interference mitigation technique based on multidimensional frequency estimation coupled with the expectation-maximization principle, which effectively resolves collisions among non-collaborative networks, thus enabling robust coexistence of multiple FH networks. To deal with possible receiver-transmitter mismatch, we also designed a low-complexity model order variation detection method. Novel multidimensional frequency estimation algorithms are also investigated.

Download or read book Performance of Fast Frequency hopping Diversity Combiners in Multiple Access Interference for Ad Hoc Networks written by Helene Ejenyi Tayong and published by . This book was released on 2006 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this work is to evaluate the performance of fast frequency-hopping diversity combiners in multiple access interference for ad hoc networks. Multiple access interference (MAI) is the interference that is common in a network with many devices sharing the channel. A model developed in, i.e. the alpha-stable distribution suggested for modeling impulsive signals, is investigated to characterize MAI for an ad hoc network. Impulsive processes are characterized by the presence of spikes or extreme outliers. As such, their probability density functions (pdfs) have heavier tails. Such impulsive behaviors have been verified experimentally in various radio and underwater acoustic channels. The characteristic exponent (the parameter alpha) controls the impulsive behavior of the process. Techniques based on characteristic functions, the Fourier transform of the probability density function (pdf), are used to calculate the probability of error since no-closed form exists for their distributions. Frequency-hopping spread spectrum (FHSS) multiple access radio networks using the same modulation and power is considered. FHSS is a powerful technique used in communication systems to provide protection against jamming and fading. The problem is applicable in wireless random-access communication systems where information about transmitters' positions is not provided. The signal strength attenuates with distance. The focus is on Fast Frequency-hopping (FFH) in order to exploit frequency diversity; a condition where the same data bit is transmitted on multiple independently faded hops. A modulation technique called frequency hopping multilevel frequency shift keying (FH-MFSK) is used to allow many users to effectively share the same frequency band. The Reduced Fuzzy Rank Order Detector (R-FROD), a FFH diversity combiner is studied in this interference environment and its performance is compared with that of hard decision majority vote (HDMV) detector, maximum rank sum receiver (MRSR) and order statistic normalized envelope detector (OS-NED). Simulation results show that the R-FROD is able to outperform the MRSR, OS-NED and HDMV detectors across a range of values for alpha. R-FROD is analyzed in alpha-stable environment using Gaussian and Cauchy membership functions. Simulation results show that either membership function can be used in R-FROD to analyze its performance in an alpha-stable environment. Increasing the hop sequence length reduces the probability of error. The analysis presented is important in the design of efficient interference suppression techniques and in solving mobile wireless communication systems. -- Abstract.

Download or read book Ad Hoc Networks written by Jun Zhi-zhong and published by Springer Science & Business Media. This book was released on 2010-12-15 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ad hoc networks, which include a variety of autonomous networks for specific purposes, promise a broad range of civilian, commercial, and military applications. These networks were originally envisioned as collections of autonomous mobile or stationary nodes that dynamically auto-configure themselves into a wireless network without relying on any existing network infrastructure or centralized administration. With the significant advances in the last decade, the concept of ad hoc networks now covers an even broader scope, referring to the many types of autonomous wireless networks designed and deployed for a specific task or function, such as wireless sensor networks, vehicular networks, home networks, and so on. In contrast to the traditional wireless networking paradigm, such networks are all characterized by sporadic connections, highly error-prone communications, distributed autonomous operation, and fragile multi-hop relay paths. The new wireless networking paradigm necessitates reexamination of many established concepts and protocols, and calls for developing a new understanding of fundamental problems such as interference, mobility, connectivity, capacity, and security, among others. While it is essential to advance theoretical research on fundamental and practical research on efficient policies, algorithms and protocols, it is also critical to develop useful applications, experimental prototypes, and real-world deployments to achieve an immediate impact on society for the success of this wireless networking paradigm.

Download or read book Robust Coexistence Methods for Frequency Hopped Wireless Networks written by Jingli Li and published by LAP Lambert Academic Publishing. This book was released on 2009-09 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the upcoming pervasive deployment of wireless networks and devices on the unlicensed band, co- channel interference caused by frequency collisions among coexisting networks have become one of the major performance limiting challenges. In recent years, the coexistence issue has gained increasing attention. However, many collision avoidance schemes are not applicable to multiple frequency hopped networks, mainly due to the fact that the frequency channels of frequency hopped signals are constantly changing and the hop sequence of one network to another is unknown. In this book, a comprehensive framework for co-channel interference mitigation and robust coexistence of multiple frequency hopped networks is developed, multiple novel techniques are introduced, and the system modeling, design, theoretic analysis, simulation, and testbed implementation are presented. This book is useful to professionals and researchers in the wireless communications field. It is also beneficial for engineers seeking new technologies to improve their wireless products' performance and to lead the market.

Download or read book Interference Mitigation in Device to Device Communications written by Masood Ur Rehman and published by John Wiley & Sons. This book was released on 2022-03-17 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore this insightful foundational resource for academics and industry professionals dealing with the move toward intelligent devices and networks Interference Mitigation in Device-to-Device Communications delivers a thorough discussion of device-to-device (D2D) and machine-to-machine (M2M) communications as solutions to the proliferation of ever more data hungry devices being attached to wireless networks. The book explores the use of D2D and M2M technologies as a key enabling component of 5G networks. It brings together a multidisciplinary team of contributors in fields like wireless communications, signal processing, and antenna design. The distinguished editors have compiled a collection of resources that practically and accessibly address issues in the development, integration, and enhancement of D2D systems to create an interference-free network. This book explores the complications posed by the restriction of device form-factors and the co-location of several electronic components in a small space, as well as the proximity of legacy systems operating in similar frequency bands. Readers will also benefit from the inclusion of: A thorough introduction to device-to-device communication, including its history and development over the last decade, network architecture, standardization issues, and regulatory and licensing hurdles An exploration of interference mitigation in device-to-device communication underlaying LTE-A networks A rethinking of device-to-device interference mitigation, including discussions of the challenges posed by the proliferation of devices An analysis of user pairing for energy efficient device-to-device content dissemination Perfect for researchers, academics, and industry professionals working on 5G networks, Interference Mitigation in Device-to-Device Communications will also earn a place in the libraries of undergraduate, graduate, and PhD students conducting research into wireless communications and applications, as well as policy makers and communications industry regulators.

Download or read book Ad Hoc Networking Towards Seamless Communications written by Liljana Gavrilovska and published by Springer Science & Business Media. This book was released on 2007-01-07 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reveals the state-of-the-art in wireless ad-hoc networking. It addresses many complex and open problems for researchers in the field of ad hoc networks. It further discusses some of the key research topics that are expected to promote and accelerate the commercial application of these networks (e.g., MAC, routing, QoS, optimization issues, service discovery, traffic models, mobility, handovers, security). It also presents "killer applications".

Download or read book Advances in Electrical Engineering and Electrical Machines written by Dehuai Zheng and published by Springer Science & Business Media. This book was released on 2012-02-01 with total page 741 pages. Available in PDF, EPUB and Kindle. Book excerpt: With success of ICEEE 2010 in Wuhan, China, and December 4 to 5, 2010, the second International Conference of Electrical and Electronics Engineering (ICEEE 2011) will be held in Macau, China, and December 1 to 2, 2011. ICEEE is an annual conference to call together researchers, engineers, academicians as well as industrial professionals from all over the world to present their research results and development activities in Electrical and Electronics Engineering along with Computer Science and Technology, Communication Technology, Artificial Intelligence, Information Technology, etc. This year ICEEE is sponsored by International Industrial Electronics Center, Hong Kong. And based on the deserved reputation, more than 750 papers have been submitted to ICEEE 2011, from which about 98 high quality original papers have been selected for the conference presentation and inclusion in the “Electrical and Electronics Engineering” book based on the referees’ comments from peer-refereed. We expect that the Electrical and Electronics Engineering book will be a trigger for further related research and technology improvements in the importance subject including Power Engineering, Telecommunication, Integrated Circuit, Electronic amplifier , Nano-technologies, Circuits and networks, Microelectronics, Analog circuits, Digital circuits, Circuits design, Silicon devices, Thin film technologies, VLSI, Sensors, CAD tools, Molecular computing, Superconductivity circuits, Antennas technology, System architectures, etc.

Download or read book Interference and Resource Management in Heterogeneous Wireless Networks written by Jiandong Li and published by Artech House. This book was released on 2017-11-30 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: This authoritative resource offers a comprehensive overview of heterogeneous wireless networks, small cells, and device-to-device (D2D) communications. The book provides insight into network modeling and performance analysis of heterogeneous wireless networks. Interference management framework and design issues are covered as well as details about resource mobility, channel models, and typical and statistical interference modeling. This resource explains leveraging resource heterogeneity in interference mitigation and presents the challenges and feasible solutions for concurrent transmission. Moreover, complete coverage of interference alignment in MIMO heterogeneous networks for both downlink and uplink is presented. This book provides performance results for an ideal partially connected interference network as well as a practical heterogeneous network. Readers find practical guidance for LTE and LTE-Advanced as well as 5G in this resource. New techniques and designs for heterogeneous wireless networks are included.

Download or read book Interference Suppression in Spread spectrum Networks written by Haichang Sui and published by . This book was released on 2007 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, interference suppression techniques and applications will be presented for cellular networks with direct-sequence (DS) CDMA and mobile ad hoc networks with frequency-hopped (FH) CDMA. The first part of the dissertation focuses on three novel finger placement designs that effectively equalize the DS-CDMA multi- path downlink channel to restore code orthogonality and consequently suppress multiple-access interference. For typical multipath channel models, the proposed schemes may significantly outperform the uniformly spaced tapped-delay-line equalizer with much less fingers/taps. In addition, analytic insight into the effect of the finger number and the smoothness of the chip pulse are obtained. The second part of the dissertation considers mobile ad hoc networks with FH-CDMA, where error-correcting codes are employed with differential unitary space-time modulation. The use of multiple transmit antennas in FH-CDMA systems, to the best knowledge of the author, has not been proposed in previous literature. The proposed receiver performs decision-feedback demodulation, decision-aided adaptive estimation, and erasure-insertion decoding jointly to suppress arbitrary unknown interference without channel state information. The third part of the dissertation presents network performance analysis for FH-CDMA networks with the proposed transceiver. Information efficiency and transmission range optimization is investigated under realistic time-varying channel models, which extends previous studies based on static channels and/or simplistic physical layer models. Impacts of various design parameters and channel properties on the network performance are revealed. The results also provide guidance on optimizing the modulation and coding scheme from a network perspective.

Download or read book Principles of Spread Spectrum Communication Systems written by Don Torrieri and published by Springer. This book was released on 2015-04-23 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook provides a concise but lucid explanation of the fundamentals of spread-spectrum systems with an emphasis on theoretical principles. The choice of specific topics is tempered by the author’s judgment of their practical significance and interest to both researchers and system designers. Throughout the book, learning is facilitated by many new or streamlined derivations of the classical theory. Problems at the end of each chapter are intended to assist readers in consolidating their knowledge and to provide practice in analytical techniques. This third edition includes new coverage of topics such as CDMA networks, Acquisition and Synchronization in DS-CDMA Cellular Networks, Hopsets for FH-CDMA Ad Hoc Networks, and Implications of Information Theory, as well as updated and revised material on Central Limit Theorem, Power Spectral Density of FH/CPM Complex Envelopes, and Anticipative Adaptive-Array Algorithm for Frequency-Hopping Systems.

Download or read book Ad Hoc and Sensor Networks written by Carlos de Morais Cordeiro and published by World Scientific. This book was released on 2011 with total page 663 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive yet easy coverage of ad hoc and sensor networks and fills the gap of existing literature in this growing field. It emphasizes that there is a major interdependence among various layers of the network protocol stack. Contrary to wired or even one-hop cellular networks, the lack of a fixed infrastructure, the inherent mobility, the wireless channel, and the underlying routing mechanism by ad hoc and sensor networks introduce a number of technological challenges that are difficult to address within the boundaries of a single protocol layer. All existing textbooks on the subject often focus on a specific aspect of the technology, and fail to provide critical insights on cross-layer interdependencies. To fully understand these intriguing networks, one need to grasp specific solutions individually, and also the many interdependencies and cross-layer interactions.

Download or read book Interference Mitigation in Wireless Communications written by Kihong Kim and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this thesis is to design advanced interference resilient schemes for asynchronous slow frequency hopping wireless personal area networks (FH-WPAN) and time division multiple access (TDMA) cellular systems in interference dominant environments. We also propose an interference-resilient power allocation method for multiple-input-multiple-output (MIMO) systems. For asynchronous FH-WPANs in the presence of frequent packet collisions, we propose a single antenna interference canceling dual decision feedback (IC-DDF) receiver based on joint maximum likelihood (ML) detection and recursive least squares (RLS) channel estimation. For the system level performance evaluation, we propose a novel geometric method that combines bit error rate (BER) and the spatial distribution of the traffic load of CCI for the computation of packet error rate (PER). We also derived the probabilities of packet collision in multiple asynchronous FH-WPANs with uniform and nonuniform traffic patterns. For the design of TDMA receivers resilient to CCI in frequency selective channels, we propose a soft output joint detection interference rejection combining delayed decision feedback sequence estimation (JD IRC-DDFSE) scheme. In the proposed scheme, IRC suppresses the CCI, while DDFSE equalizes ISI with reduced complexity. Also, the soft outputs are generated from IRC-DDFSE decision metric to improve the performance of iterative or non-iterative type soft-input outer code decoders. For the design of interference resilient power allocation scheme in MIMO systems, we investigate an adaptive power allocation method using subset antenna transmission (SAT) techniques. Motivated by the observation of capacity imbalance among the multiple parallel sub-channels, the SAT method achieves high spectral efficiency by allocating power on a selected transmit antenna subset. For 4 x 4 V-BLAST MIMO systems, the proposed scheme with SAT showed analogous results. Adaptive modulation schemes combined with the proposed method increase the capacity gains. From a feasibility viewpoint, the proposed method is a practical solution to CCI-limited MIMO systems since it does not require the channel state information (CSI) of CCI.

Download or read book Cognitive Radio Software Defined Radio and Adaptive Wireless Systems written by Hüseyin Arslan and published by Springer Science & Business Media. This book was released on 2007-08-17 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today’s wireless services have come a long way since the roll out of the conventional voice-centric cellular systems. The demand for wireless access in voice and high rate data multi-media applications has been increasing. New generation wireless communication systems are aimed at accommodating this demand through better resource management and improved transmission technologies. This book discusses the cognitive radio, software defined radio, and adaptive radio concepts from several perspectives.

Download or read book Ultra Wideband Wireless Communication written by Huseyin Arslan and published by John Wiley & Sons. This book was released on 2006-10-13 with total page 533 pages. Available in PDF, EPUB and Kindle. Book excerpt: ULTRA WIDEBAND WIRELESS COMMUNICATION AN INTERNATIONAL PANEL OF EXPERTS PROVIDE MAJOR RESEARCH ISSUES AND A SELF-CONTAINED, RAPID INTRODUCTION TO THE THEORY AND APPLICATION OF UWB This book delivers end-to-end coverage of recent advances in both the theory and practical design of ultra wideband (UWB) communication networks. Contributions offer a worldwide perspective on new and emerging applications, including WPAN, sensor and ad hoc networks, wireless telemetry, and telemedicine. The book explores issues related to the physical layer, medium access layer, and networking layer. Following an introductory chapter, the book explores three core areas: Analysis of physical layer and technology issues System design elements, including channel modeling, coexistence, and interference mitigation and control Review of MAC and network layer issues, up to the application Case studies present examples such as network and transceiver design, assisting the reader in understanding the application of theory to real-world tasks. Ultra Wideband Wireless Communication enables technical professionals, graduate students, engineers, scientists, and academic and professional researchers in mobile and wireless communications to become conversant with the latest theory and applications by offering a survey of all important topics in the field. It also serves as an advanced mathematical treatise; however, the book is organized to allow non-technical readers to bypass the mathematical treatments and still gain an excellent understanding of both theory and practice.

Download or read book Mobile Ad Hoc Networks written by Xin Wang and published by BoD – Books on Demand. This book was released on 2011-01-30 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: vehicular ad-hoc networks, security and caching, TCP in ad-hoc networks and emerging applications. It is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks.