Abstract: AbstractThe network calculus is a framework for the analysis of communication networks,which exploits that many computer network models become tractablefor analysis if they are expressed in a min-plus or max-plus algebra. In amin-plus algebra, the network calculus characterizes amounts of traffic andavailable service as functions of time. In a max-plus algebra, the network calculusworks with functions that express the arrival and departure times or therequired service time for a given amount of traffic. While the min-plus networkcalculus is more convenient for capacity provisioning in a network, themax-plus network calculus is more compatible with traffic control algorithmsthat involve the computation of timestamps. Many similarities and relationshipsbetween the two versions of the network calculus are known, yet theyare largely viewed as distinct analytical approaches with different capabilitiesand limitations. We show that there exists a one-to-one correspondencebetween the min-plus and max-plus network calculus, as long as traffic andservice are described by functions with real-valued domains and ranges. Consequently,results from one version of the network calculus can be readilyapplied for computations in the other version. The ability to switch betweenmin-plus and max-plus analysis without any loss of accuracy provides additionalflexibility for characterizing and analyzing traffic control algorithms.This flexibility is exploited for gaining new insights into link scheduling algorithmsthat offer rate and delay guarantees to traffic flows.Suggested CitationJörg Liebeherr (2017), "Duality of the Max-Plus and Min-Plus Network Calculus", Foundations and Trends® in Networking: Vol. 11: No. 3-4, pp 139-282. http://dx.doi.org/10.1561/1300000059 PubDate: Mon, 10 Jul 2017 00:00:00 +020

Abstract: AbstractRandom access represents possibly the simplest and yet one of the best known approaches for sharing a channel among several users. Since their introduction in the 1970s, random access schemes have been thoroughly studied and small variations of the pioneering Aloha protocol have since then become a key component of many communications standards, ranging from satellite networks to ad hoc and cellular scenarios. A fundamental step forward for this old paradigm has been witnessed in the past few years, with the development of new solutions, mainly based on the principles of successive interference cancellation, which made it possible to embrace constructively collisions among packets rather enduring them as a waste of resources. These new lines of research have rendered the performance of modern random access protocols competitive to that of their coordinated counterparts, paving the road for a multitude of new applications.This monograph explores the main ideas and design principles that are behind some of such novel schemes, and aims at offering to the reader an introduction to the analytical tools that can be used to model their performance. After reviewing some relevant results for the random access channel, the volume focuses on slotted solutions that combine the approach of diversity Aloha with successive interference cancellation, and discusses their optimisation based on an analogy with the theory of codes on graphs. The potential of modern random access is then further explored considering two families of schemes: the former based on physical layer network coding to resolve collisions among users, and the latter leaning on the concept of receiver diversity. Finally, the opportunities and the challenges encountered by random access solutions recently devised to operate in asynchronous, i.e., unslotted, scenarios are reviewed and discussedSuggested CitationMatteo Berioli, Giuseppe Cocco, Gianluigi Liva and Andrea Munari (2016), "Modern Random Access Protocols", Foundations and Trends® in Networking: Vol. 10: No. 4, pp 317-446. http://dx.doi.org/10.1561/1300000047 PubDate: Thu, 17 Nov 2016 00:00:00 +010

Abstract: AbstractWireless multi-hop networks have become an important part of many modern communication systems. Opportunistic routing aims to overcome the deficiencies of conventional routing on wireless multi-hop networks, by specifically utilizing wireless broadcast opportunities and receiver diversity. Opportunistic routing algorithms, which are specifically optimized to incorporate into the routing decisions a model of wireless transmission, take advantage of scheduling, multi-user, andreceiver diversity gains and result in significant reduction in the expected cost of routing per packet. The ability of the algorithm to take advantage of the aspects of wireless transmission, however, depends on the scalability and the additional overhead associated with the opportunistic routing as well as the availability of side information regarding wireless channel statistics, topology, etc. This monograph sheds light on the performance gains associated with incorporating into the routing strategy the nature of wireless transmission.This monograph first provides an overview of various opportunistic distance-vector algorithms that have been developed to incorporate wireless transmission and routing opportunities. Furthermore, an optimal opportunistic distance metric is proposed whose performance is examined against the performance of several routing algorithms from the literature. The performance is examined first in analytical examples, then via simulation to identify the strengths of the optimal opportunist routing algorithm. To allow for a scalable and distributed solution, the distributed computation of this optimal distance-metric is provided. The performance of a distributed implementation of the optimal opportunistic routing algorithm is also examined via simulation. In addition to the construction of the opportunistic schemes in centralized and distributed fashions, this monograph also addresses how learning the wireless medium can be efficiently incorporated in the structure of routing algorithm. Finally, this monograph examines the dynamic congestion-based distance metric and its performance against other congestion aware solutions in the literature.Suggested CitationTara Javidi and Eric Van Buhler (2016), "Opportunistic Routing in Wireless Networks", Foundations and Trends® in Networking: Vol. 10: No. 4. http://dx.doi.org/10.1561/1300000021 PubDate: Wed, 31 Aug 2016 00:00:00 +020

Abstract: AbstractThe smart energy grid has evolved into a complex ecosystem, with new entering actors such as aggregators, and traditional ones like consumers, operators and generators having fundamentally different, active roles in the system. In addition, advances in key technologies such as renewables, energy storage, communication and control have paved the way to new research directions and problems. In this work we attempt to give some structure to the complex ecosystem above, and we present key research problems that shape the area. The emphasis is on the control and optimization methodology toward approaching these problems. The first thread we consider is demand-response where the central theme is to optimize the demand load of consumers. The basic problem is the scheduling of demand load of consumers with the aim to minimize a cost function from the point of view of the utility operator or the consumer. Next, we review fundamental problems in energy storage management. The basic energy storage management problem amounts to deciding when and how much to charge and discharge the battery in order to achieve a certain optimization objective, either in terms of a generation cost or a mismatch between energy demand and supply, which again may capture the goals of the consumer or the utility. We also discuss the market interactions of various entities in the smart grid ecosystem and the impact of their strategic decisions on the market structure. Finally, we study key aspects of consumer behavior such as response to gamification models, and uncertainty due to consumer decisions that influence the system, and we discuss the role of data in building data-driven models for predicting consumer behavior. For each problem instance above, we provide an exposition that places emphasis on the related model and on key aspects of the analysis.Suggested CitationIordanis Koutsopoulos, Thanasis G. Papaioannou and Vasiliki Hatzi (2016), "Modeling and Optimization of the Smart Grid Ecosystem", Foundations and Trends® in Networking: Vol. 10: No. 2-3, pp 115-316. http://dx.doi.org/10.1561/1300000042 PubDate: Wed, 22 Jun 2016 00:00:00 +020

Abstract: AbstractFuture vehicles will require massive sensing capability. Leveraging only onboard sensors, though, is challenging in crowded environments where the sensing field-of-view is obstructed. One potential solution is to share sensor data among the vehicles and infrastructure. This has the benefits of providing vehicles with an enhanced field-of-view and also additional redundancy to provide more reliability in the sensor data. A main challenge in sharing sensor data is providing the high data rates required to exchange raw sensor data. The large spectral channels at millimeter wave (mmWave) frequencies provide a means of achieving much higher data rates. This monograph provides an overview of mmWave vehicular communication with an emphasis on results on channel measurements, the physical (PHY) layer, and the medium access control (MAC) layer. The main objective is to summarize key findings in each area, with special attention paid to identifying important topics of future research. In addition to surveying existing work, some new simulation results are also presented to give insights on the effect of directionality and blockage, which are the two distinguishing features of mmWave vehicular channels. A main conclusion of this monograph is that given the renewed interest in high rate vehicle connectivity, many challenges remain in the design of a mmWave vehicular network.Suggested CitationVutha Va, Takayuki Shimizu, Gaurav Bansal and Robert W. Heath Jr. (2016), "Millimeter Wave Vehicular Communications: A Survey", Foundations and Trends® in Networking: Vol. 10: No. 1, pp 1-113. http://dx.doi.org/10.1561/1300000054 PubDate: Wed, 22 Jun 2016 00:00:00 +020

Abstract: AbstractDistributed storage has been an active research area for decades. With the proliferation of cloud computing, there has been a rejuvenated interest in two perspectives. The first perspective is seen through the lenses of the cloud providers: how should we build global storage services for cloud hosted services and applications at scale with high reliability and availability guarantees, but also in a cost effective way' The second perspective is seen through the lenses of the service providers that utilize public clouds: how can we achieve high I/O performance over cloud storage within a cost budget' In this manuscript, we first present various kinds of distributed storage systems, their operational characteristics and the key techniques to improve their performance. We then focus on cloud storage, exclusively. Cloud storage has massive scales with the promise to provide as much storage capacity as their tenants demand. Cloud providers also promise very high durability, availability, and I/O performance. In this context, we cover the fundamental tradeoffs between storage efficiency and network bandwidth as well as I/O throughput and latency. Erasure codes play an essential role in these tradeoffs and, thus, we also present their design and usage in the context of cloud storage broadly. We pay particular attention on various queuing models and the corresponding performance analysis in the presence of coded storage. We provide exact and approximate solutions under various settings and assumptions. We describe optimal or near-optimal scheduling and coding strategies that are established based on these analyses.Suggested CitationUlas C. Kozat and Guanfeng Liang (2015), "Building Reliable Storage Clouds: Models, Fundamental Tradeoffs, and Solutions", Foundations and Trends® in Networking: Vol. 9: No. 4, pp 219-3115. http://dx.doi.org/10.1561/1300000051 PubDate: Thu, 17 Dec 2015 00:00:00 +010

Abstract: AbstractA basic question in wireless networking is how to optimize the wireless network resource allocation for utility maximization and interference management. How can we overcome interference to efficiently optimize fair wireless resource allocation, under various stochastic constraints on quality of service demands' Network designs are traditionally divided into layers. How does fairness permeate through layers' Can physical layer innovation be jointly optimized with network layer routing control' How should large complex wireless networks be analyzed and designed with clearly-defined fairness using beamforming' This monograph provides a comprehensive survey of the models, algorithms, analysis, and methodologies using a Perron-Frobenius theoretic framework to solve wireless utility maximization problems. This approach overcomes the notorious non-convexity barriers in these problems, and the optimal value and solution of the optimization problems can be analytically characterized by the spectral property of matrices induced by nonlinear positive mappings. It also provides a systematic way to derive distributed and fast-convergent algorithms and to evaluate the fairness of resource allocation. This approach can even solve several previously open problems in the wireless networking literature. More generally, this approach links fundamental results in nonnegative matrix theory and (linear and nonlinear) Perron-Frobenius theory with the solvability of non-convex problems. In particular, for seemingly nonconvex problems, e.g., max-min wireless fairness problems, it can solve them optimally; for truly nonconvex problems, e.g., sum rate maximization, it can even be used to identify polynomial-time solvable special cases or to enable convex relaxation for global optimization.To highlight the key aspects, we also list several case studies of using the nonlinear Perron-Frobenius theoretic framework for applications in MIMO wireless cellular, heterogeneous small-cell and cognitive radio networks. Key implications arising from these work along with severalopen issues are discussed in this monograph.Suggested CitationChee Wei Tan (2015), "Wireless Network Optimization by Perron-Frobenius Theory", Foundations and Trends® in Networking: Vol. 9: No. 2-3, pp 107-218. http://dx.doi.org/10.1561/1300000048 PubDate: Thu, 03 Dec 2015 00:00:00 +010

Abstract: AbstractThe current process of designing secure protocols is tantamount to an arms race between attacks and “patches”. We introduce a system theoretic approach to secure protocol design with provable security guarantees against all attacks that fall within the system model. In this approach, we frame the secure protocol design problem as a max-min optimization of a specific payoff function, where the adversarial nodes with a priori knowledge of the protocol choose a strategy that minimizes the payoff, and the protocol seeks to maximize this worst-case payoff. We make the following three contributions. First, we solve the optimization problem. That is, we describe a protocol and show that is max-min optimal. Second, we show that the protocol is actually min-max optimal which is generally higher than max-min optimality. Finally, we show that the adversarial nodes are effectively limited to one of two modes: either jamming or conforming with the protocol.Suggested CitationJonathan Ponniah, Yih-Chun Hu and P. R. Kumar (2015), "A Clean Slate Approach to Secure Wireless Networking", Foundations and Trends® in Networking: Vol. 9: No. 1, pp 1-105. http://dx.doi.org/10.1561/1300000037 PubDate: Mon, 24 Aug 2015 00:00:00 +020

Abstract: AbstractIn this monograph we provided a tutorial on a family of sequential learning and decision problems known as the multi-armed bandit problems. We introduced a wide range of application scenarios for this learning framework, as well as its many different variants. The more detailed discussion has focused more on the stochastic bandit problems, with rewards driven by either an IID or a Markovian process, and when the environment consists of a single or multiple simultaneous users. We also presented literature on learning of MDPs, which captures coupling among the evolution of different options that a classical MAB problem does not.Suggested CitationCem Tekin and Mingyan Liu (2015), "Online Learning Methods for Networking", Foundations and Trends® in Networking: Vol. 8: No. 4, pp 281-409. http://dx.doi.org/10.1561/1300000050 PubDate: Mon, 19 Jan 2015 00:00:00 +010

Abstract: AbstractMulti-hop communication paradigms are expected to play a central role in future wireless networks by enabling a higher spatial reuse of the spectrum. A major challenge in multi-hop multi-user (or multi-flow) wireless networks is that "interference management" and "relaying" are coupled with each other. In other words, wireless relay nodes must play a dual role: they serve as intermediate steps for multi-hop communication and as part of the mechanism that allows interference management schemes. Nonetheless, in the communications, networking and information theory literature, these two tasks have traditionally been addressed separately, and the fundamental principles of the "wireless networks of the future" are currently not well understood. In this monograph, we take a unified approach to relaying and interference management, and seek to develop tools to study the fundamentals of multi-hop multi-flowwireless networks. We first consider multi-hop two-flow – or two-unicast – wireless networks. In order to handle networks with an arbitrary number of hops and arbitrary interference patterns, we introduce the idea of network condensation, by which a network with an arbitrary number of layers is effectively reduced to a network with at most four layers. This is done by identifying key layers and letting the nodes in all other layers apply random linear coding to relay the messages. Only the nodes in the remaining key layers need to be "smart" and perform coupled relaying and interference management operations. In addition, we introduce the new notion of paths with manageable interference, which represents a first attempt at finding flow-like structures in multi-user wireless networks, and develop novel outer bounds that capture the interference structure of a given topology. These techniques yield a complete characterization of the degrees of freedom of two-unicast layered networks as a function of the network graph. Extending these results for general K-unicast networks is quite challenging. To make progress on this front, we focus on the K x K x K wireless network, a two-hop network consisting of K sources, K relays, and K destinations. This network represents a canonical example of a multi-hop multi-flow wireless network for which previously there was a large gap between known inner and outer bounds, even from a degrees-of-freedom perspective. We introduce a coding scheme called Aligned Network Diagonalization (AND) that couples relaying and interference management in a way that all interference experienced by the destinations is simultaneously neutralized. This proves that K x K x K wireless networks have K sum degrees of freedom and demonstrates the significant gains that can be obtained with a unified approach to relaying and interference management. Moreover, this automotically yields the optimal scheme and degrees-of-freedom characterization for layered K unicast networks with fully connected hops. We then describe ideas and preliminary results for K-unicast networks with general topologies. Besides discussing how the tools developed for two-unicast networks and for K x K x K networks can be extended to this general setting, we present a novel outer-bounding technique, which improves over the cut-set bound and can capture limitations imposed by the interference between different users. The new bound can be understood as computing the flow across multiple "nested cuts", as opposed to a single cut, as is the case in the classical cut-set bound. This technique allows us to establish a graph-theoretic notion of manageable interference in K x K x K wireless networks with arbitrary connectivity. Throughout the monograph, many extensions and future directions are addressed. At the end of each chapter, related work is also described and several open problems are presented. Important research directions such as accounting for the lack of global channel state information in large networks and reducing the complexity of relaying operations are discussed, and recent results along these lines are described.Suggested CitationIlan Shomorony and Salman Avestimehr (2014), "Multihop Wireless Networks: A Unified Approach to Relaying and Interference Management", Foundations and Trends® in Networking: Vol. 8: No. 3, pp 149-280. http://dx.doi.org/10.1561/1300000044 PubDate: Wed, 03 Dec 2014 00:00:00 +010

Abstract: AbstractMolecular communication (MC) is a promising bio-inspired paradigm for the interconnection of autonomous nanotechnology-enabled devices, or nanomachines, into nanonetworks. MC realizes the exchange of information through the transmission, propagation, and reception of molecules, and it is proposed as a feasible solution for nanonetworks. This idea is motivated by the observation of nature, where MC is successfully adopted by cells for intracellular and intercellular communication. MC-based nanonetworks have the potential to be the enabling technology for a wide range of applications, mostly in the biomedical, but also in the industrial and surveillance fields. The focus of this article is on the most fundamental type of MC, i.e., diffusion-based MC, where the propagation of information-bearing molecules between a transmitter and a receiver is realized through free diffusion in a fluid. The objectives of the research presented in this article are to analyze an MC link from the point of view of communication engineering and information theory, and to provide solutions to the modeling and design of MC-based nanonetworks. First, a deterministic model is realized to study each component, as well as the overall diffusion-based- MC link, in terms of gain and delay. Second, the noise sources affecting a diffusion-based-MC link are identified and statistically modeled. Third, upper/lower bounds to the capacity are derived to evaluate the information-theoretic performance of diffusion-based MC. Fourth, an analysis of the interference produced by multiple diffusion-based MC links in a nanonetwork is provided. This research provides fundamental results that establish a basis for the modeling, design, and realization of future MC-based nanonetworks, as novel technologies and tools are being developed.Suggested CitationMassimiliano Pierobon and Ian F. Akyildiz (2014), "Fundamentals of Diffusion-Based Molecular Communication in Nanonetworks", Foundations and Trends® in Networking: Vol. 8: No. 1-2, pp 1-147. http://dx.doi.org/10.1561/1300000033 PubDate: Wed, 23 Apr 2014 00:00:00 +020

Abstract: AbstractWe present a review of the notion of stability and of stable throughput regions in wireless networks, with emphasis on network layer cooperation between interacting users. After a brief introduction, we examine in detail specific instances of the stability issue. These instances differ from each other in terms of the network, channel and traffic models they use. What they share is the notion of how stability is affected by node cooperation, as well as the notion of "interacting queues" that makes the stable throughput analysis difficult and often intractable. This review is intended to provide a reference point for the rich set of network control problems that arise in the context of queue stability in modern and future networks.Suggested CitationSastry Kompella and Anthony Ephremides (2014), "Stable Throughput Regions in Wireless Networks", Foundations and Trends® in Networking: Vol. 7: No. 4, pp 235-338. http://dx.doi.org/10.1561/1300000039 PubDate: Thu, 13 Mar 2014 00:00:00 +010

Abstract: AbstractNanotechnology is providing a new set of tools to the engineering community to design nanoscale components withunprecedented functionalities. The integration of several nano-components into a single entity will enable thedevelopment of advanced nanomachines. Nanonetworks, i.e., networks of nanomachines, will enable a plethora ofapplications in the biomedical, environmental, industrial and military fields. To date, it is still not clear hownanomachines will communicate. The miniaturization of a classical antenna to meet the size requirements ofnanomachines would impose the use of very high radiation frequencies, which would compromise the feasibility ofelectromagnetic nanonetworks. Therefore, a new wireless technology is needed to enable this paradigm. The objectiveof this work is to establish the foundations of graphene–enabled electromagnetic communication in nanonetworks.First, novel graphene-based plasmonic nano-antennas are proposed, modeled and analyzed. The obtained results pointto the Terahertz Band (0.1–10 THz) as the frequency range of operation of novel nano–antennas. For this, the secondcontribution in this work is the development of a novel channel model for Terahertz Band communication. In addition,the channel capacity of the Terahertz Band is numerically investigated to highlight the potential of thisstill–unregulated frequency band. Third, new communication mechanisms for electromagnetic nanonetworks are developed.These include a novel modulation based on the transmission of femtosecond-long pulses, new low-weight codes for channelerror prevention in nanonetworks, a novel symbol detection scheme at the nano–receiver, a new energy model forself–powered nanomachines with piezoelectric nano–generators, and a new Medium Access Control protocol tailored tothe Terahertz Band. Finally, a one–to–one nano-link is emulated to validate the proposed solutions.Suggested CitationJosep Miquel Jornet and Ian F. Akyildiz (2013), "Fundamentals of Electromagnetic Nanonetworks in the Terahertz Band", Foundations and Trends® in Networking: Vol. 7: No. 2-3, pp 77-233. http://dx.doi.org/10.1561/1300000045 PubDate: Thu, 05 Dec 2013 00:00:00 +010

Abstract: AbstractOptimization has been widely used in recent design of communication and networking systems. One major hurdle in this endeavor lies in the nonconvexity of many optimization problems that arise from practical systems. To address this issue, we observe that most nonconvex problems encountered in communication and networking systems exhibit monotonicity or hidden monotonicity structures. A systematic use of the monotonicity properties would substantially alleviate the difficulty in obtaining the global optimal solutions of the problems. This monograph provides a succinct and accessible introduction to monotonic optimization, including the formulation skills and solution algorithms. Through several application examples, we will illustrate modeling techniques and algorithm details of monotonic optimization in various scenarios. With this promising technique, many previously difficult problems can now be solved with great efficiency. With this monograph, we wish to spur new research activities in broadening the scope of application of monotonic optimization in communication and networking systems.Suggested CitationYing Jun (Angela) Zhang, Liping Qian and Jianwei Huang (2013), "Monotonic Optimization in Communication and Networking Systems", Foundations and Trends® in Networking: Vol. 7: No. 1, pp 1-75. http://dx.doi.org/10.1561/1300000038 PubDate: Mon, 14 Oct 2013 00:00:00 +020

Abstract: AbstractWe consider geometric random graphs where n points are distributed independently on the unit interval [0, 1] according to some probability distribution function F with density function f. Two nodes communicate with each other if their distance is less than some transmission range. For this class of random graphs, we survey results concerning the existence of zero-one laws for graph connectivity, the type of the zero-one law obtained under specific assumptions on the density function f, the form of its critical scaling and its dependence on f, and the width of the corresponding phase transitions. This is motivated by the desire to understand how node distribution affects the critical transmission range as specified by the disk model. Engineering implications are discussed for power allocation.Suggested CitationArmand M. Makowski and Guang Han (2013), "On the Sensitivity of the Critical Transmission Range: Lessons from the Lonely Dimension", Foundations and Trends® in Networking: Vol. 6: No. 4, pp 287-399. http://dx.doi.org/10.1561/1300000029 PubDate: Wed, 18 Sep 2013 00:00:00 +020

Abstract: AbstractIn recent years, engineers have been increasingly called upon to have basic skills in economic modeling and game theory at their disposal for two related reasons. First, the economics of networks has a significant effect on the adoption and creation of network innovations, and second, and perhaps more importantly, engineered networks serve as the platform for many of our basic economic interactions today. This monograph aims to provide engineering students who have a basic training in economic modeling and game theory an understanding of where and when game theoretic models are employed, the assumptions underpinning key models, and conceptual insights that are broadly applicable.Suggested CitationRandall A. Berry and Ramesh Johari (2013), "Economic Modeling in Networking: A Primer", Foundations and Trends® in Networking: Vol. 6: No. 3, pp 165-286. http://dx.doi.org/10.1561/1300000011 PubDate: Wed, 15 May 2013 00:00:00 +020

Abstract: AbstractA wide variety of resource management problems of recent interest, including power/rate control, link scheduling, cross-layer control, network utility maximization, beamformer design of multiple-input multiple-output networks, and many others are directly or indirectly reliant on the weighted sum-rate maximization (WSRMax) problem. In general, this problem is very difficult to solve and is NP-hard. In this review, we provide a cohesive discussion of the existing solution methods associated with the WSRMax problem, including global, fast local, as well as decentralized methods. We also discuss in depth the applications of general optimization techniques, such as branch and bound methods, homotopy methods, complementary geometric programming, primal decomposition methods, subgradient methods, and sequential approximation strategies, in order to develop algorithms for the WSRMax problem. We show, through a number of numerical examples, the applicability of these algorithms in various application domains.Suggested CitationPradeep Chathuranga Weeraddana, Marian Codreanu, Matti Latva-aho, Anthony Ephremides and Carlo Fischione (2012), "Weighted Sum-Rate Maximization in Wireless Networks: A Review", Foundations and Trends® in Networking: Vol. 6: No. 1–2, pp 1-163. http://dx.doi.org/10.1561/1300000036 PubDate: Mon, 15 Oct 2012 00:00:00 +020

Abstract: AbstractWireless Underground Sensor Networks (WUSNs) are the networks of wireless sensors that operate in the underground soil medium. In this monograph, to realize reliable and efficient WUSNs, two enabling techniques are developed to address the challenges brought by the underground soil medium, including the EM wave-based WUSNs and the MI-based WUSNs. For EM wave-based WUSNs, the heterogeneous network architecture and dynamic connectivity are investigated based on a comprehensive channel model in soil medium. Then a spatio-temporal correlation-based data collection scheme is developed to reduce the sensor density while keeping high monitoring accuracy. For MI-based WUSNs, the MI channel is first analytically characterized. Then based on the MI channel model, the MI waveguide technique is developed in order to enlarge the underground transmission range. After that, the optimal deployment algorithms for MI waveguides in WUSNs are analyzed to construct the WUSNs with high reliability and low costs. Finally, the mathematical models are developed to evaluate the channel and network capacities of MI-based WUSNs. This monograph provides principles and guidelines for WUSN designs.Suggested CitationZhi Sun and Ian F. Akyildiz (2012), "Key Communication Techniques for Underground Sensor Networks", Foundations and Trends® in Networking: Vol. 5: No. 4, pp 283-420. http://dx.doi.org/10.1561/1300000034 PubDate: Wed, 25 Apr 2012 00:00:00 +020

Abstract: AbstractTransmission capacity (TC) is a performance metric for wireless networks that measures the spatial intensity of successful transmissions per unit area, subject to a constraint on the permissible outage probability (where outage occurs when the signal to interference plus noise ratio (SINR) at a receiver is below a threshold). This volume gives a unified treatment of the TC framework that has been developed by the authors and their collaborators over the past decade. The mathematical framework underlying the analysis (reviewed in Section 2) is stochastic geometry: Poisson point processes model the locations of interferers, and (stable) shot noise processes represent the aggregate interference seen at a receiver. Section 3 presents TC results (exact, asymptotic, and bounds) on a simple model in order to illustrate a key strength of the framework: analytical tractability yields explicit performance dependence upon key model parameters. Section 4 presents enhancements to this basic model — channel fading, variable link distances (VLD), and multihop. Section 5 presents four network design case studies well-suited to TC: (i) spectrum management, (ii) interference cancellation, (iii) signal threshold transmission scheduling, and (iv) power control. Section 6 studies the TC when nodes have multiple antennas, which provides a contrast vs. classical results that ignore interference.Suggested CitationSteven Weber and Jeffrey G. Andrews (2012), "Transmission Capacity of Wireless Networks", Foundations and Trends® in Networking: Vol. 5: No. 2–3, pp 109-281. http://dx.doi.org/10.1561/1300000032 PubDate: Fri, 13 Jan 2012 00:00:00 +010

Abstract: AbstractMulti-hop is the current communication architecture of wireless mesh and ad hoc networks. Information is relayed from each source to its destination in successive transmissions between intermediate nodes. A major problem regarding this architecture is its poor performance at large system size: as the number of users in a wireless network increases, the communication rate for each user rapidly decreases. Can we design new communication architectures that significantly increase the capacity of large wireless networks'In this monograph, we present a scaling law characterization of the information-theoretic capacity of wireless networks, which sheds some light on this question. We show that the answer depends on the parameter range in which a particular network lies, namely the operating regime of the network. There are operating regimes where the information-theoretic capacity of the network is drastically higher than the capacity of conventional multi-hop. New architectures can provide substantial capacity gains here. We determine what these regimes are and investigate the new architectures that are able to approach the information-theoretic capacity of the network. In some regimes, there is no way to outperform multi-hop. In other words, the conventional multi-hop architecture indeed achieves the information-theoretic capacity of the network. We discuss the fundamental factors limiting the capacity of the network in these regimes and provide an understanding of why conventional multi-hop indeed turns out to be the right architecture.The monograph is structured as follows: In Section 2, we discuss the role of interference in wireless networks. We show that while current communication architectures are fundamentally limited by interference, new architectures based on distributed MIMO communication can overcome this interference limitation, yielding drastic performance improvements. Section 3 discusses the impact of power. We show that in power-limited regimes, distributed MIMO-based techniques are important not only because they remove interference but also because they provide received power gain. We identify the power-limited operating regimes of wireless networks and define the engineering quantities that determine the operating regime of a given wireless network. We show that unless the wireless network operates in a severely power-limited regime, distributed MIMO communication provides significant capacity gain over current techniques. Finally, in Section 4, we study how the area of the network, i.e., space, impacts the capacity of the network. This study enriches the earlier picture by adding new operating regimes where wireless networks can be moderately or severely space-limited. We see that unless the network is severely limited in space, distributed-MIMO-based communication continues to provide drastic improvements over conventional multi-hop.Suggested CitationAyfer Özgür, Olivier Lévêque and David Tse (2011), "Operating Regimes of Large Wireless Networks", Foundations and Trends® in Networking: Vol. 5: No. 1, pp 1-107. http://dx.doi.org/10.1561/1300000016 PubDate: Tue, 20 Dec 2011 00:00:00 +010

Abstract: AbstractWe present a review of the problem of scheduled channel access in wireless networks with emphasis on ad hoc and sensor networks as opposed to WiFi, cellular, and infrastructure-based networks. After a brief introduction and problem definition, we examine in detail specific instances of the scheduling problem. These instances differ from each other in a number of ways, including the detailed network model and the objective function or performance criteria. They all share the "layerless" viewpoint that connects the access problem with the physical layer and, occasionally, with the routing layer. This review is intended to provide a reference point for the rich set of problems that arise in the allocation of resources in modern and future networks.Suggested CitationAnna Pantelidou and Anthony Ephremides (2011), "Scheduling in Wireless Networks", Foundations and Trends® in Networking: Vol. 4: No. 4, pp 421-511. http://dx.doi.org/10.1561/1300000030 PubDate: Fri, 15 Apr 2011 00:00:00 +020

Abstract: AbstractIn this monograph we survey results from a newly emerging line of research that targets algorithm analysis in the physical interference model. In the main part of our monograph we focus on wireless scheduling: given a set of communication requests, arbitrarily distributed in space, how can these requests be scheduled efficiently' We study the difficulty of this problem and we examine algorithms for wireless scheduling with provable performance guarantees. Moreover, we present a few results for related problems and give additional context.Suggested CitationOlga Goussevskaia, Yvonne-Anne Pignolet and Roger Wattenhofer (2010), "Efficiency of Wireless Networks: Approximation Algorithms for the Physical Interference Model", Foundations and Trends® in Networking: Vol. 4: No. 3, pp 313-420. http://dx.doi.org/10.1561/1300000019 PubDate: Thu, 16 Dec 2010 00:00:00 +010

Abstract: AbstractThis volume bears on wireless network modeling and performance analysis. The aim is to show how stochastic geometry can be used in a more or less systematic way to analyze the phenomena that arise in this context. It first focuses on medium access control mechanisms used in ad hoc networks and in cellular networks. It then discusses the use of stochastic geometry for the quantitative analysis of routing algorithms in mobile ad hoc networks. The appendix also contains a concise summary of wireless communication principles and of the network architectures considered in the two volumes.Suggested CitationFrançois Baccelli and Bartłomiej Błaszczyszyn (2010), "Stochastic Geometry and Wireless Networks: Volume II Applications", Foundations and Trends® in Networking: Vol. 4: No. 1–2, pp 1-312. http://dx.doi.org/10.1561/1300000026 PubDate: Mon, 18 Jan 2010 00:00:00 +010

Abstract: AbstractVolume I first provides a compact survey on classical stochastic geometry models, with a main focus on spatial shot-noise processes, coverage processes and random tessellations. It then focuses on signal to interference noise ratio (SINR) stochastic geometry, which is the basis for the modeling of wireless network protocols and architectures considered in Volume II. It also contains an appendix on mathematical tools used throughout Stochastic Geometry and Wireless Networks, Volumes I and II.Suggested CitationFrançois Baccelli and Bartłomiej Błaszczyszyn (2010), "Stochastic Geometry and Wireless Networks: Volume I Theory", Foundations and Trends® in Networking: Vol. 3: No. 3–4, pp 249-449. http://dx.doi.org/10.1561/1300000006 PubDate: Mon, 18 Jan 2010 00:00:00 +010

Abstract: AbstractSince interference is the main performance-limiting factor in most wireless networks, it is crucial to characterize the interference statistics. The two main determinants of the interference are the network geometry (spatial distribution of concurrently transmitting nodes) and the path loss law (signal attenuation with distance). For certain classes of node distributions, most notably Poisson point processes, and attenuation laws, closed-form results are available, for both the interference itself as well as the signal-to-interference ratios, which determine the network performance.This monograph presents an overview of these results and gives an introduction to the analytical techniques used in their derivation. The node distribution models range from lattices to homogeneous and clustered Poisson models to general motion-invariant ones. The analysis of the more general models requires the use of Palm theory, in particular conditional probability generating functionals, which are briefly introduced in the appendix.Suggested CitationMartin Haenggi and Radha Krishna Ganti (2009), "Interference in Large Wireless Networks", Foundations and Trends® in Networking: Vol. 3: No. 2, pp 127-248. http://dx.doi.org/10.1561/1300000015 PubDate: Wed, 25 Nov 2009 00:00:00 +010

Abstract: AbstractUnlike the Telephone network or the Internet, many of the next generation networks are not engineered for the purpose of providing efficient communication between various networked entities. Examples abound: sensor networks, peer-to-peer networks, mobile networks of vehicles and social networks. Indeed, these emerging networks do require algorithms for communication, computation, or merely spreading information. For example, estimation algorithms in sensor networks, broadcasting news through a peer-to-peer network, or viral advertising in a social network. These networks lack infrastructure; they exhibit unpredictable dynamics and they face stringent resource constraints. Therefore, algorithms operating within them need to be extremely simple, distributed, robust against networks dynamics, and efficient in resource utilization.Gossip algorithms, as the name suggests, are built upon a gossip or rumor style unreliable, asynchronous information exchange protocol. Due to their immense simplicity and wide applicability, this class of algorithms has emerged as a canonical architectural solution for the next generation networks. This has led to exciting recent progress to understand the applicability as well as limitations of the Gossip algorithms. In this review, we provide a systematic survey of many of these recent results on Gossip network algorithms. The algorithmic results described here utilize interdisciplinary tools from Markov chain theory, Optimization, Percolation, Random graphs, Spectral graph theory, and Coding.Suggested CitationDevavrat Shah (2009), "Gossip Algorithms", Foundations and Trends® in Networking: Vol. 3: No. 1, pp 1-125. http://dx.doi.org/10.1561/1300000014 PubDate: Tue, 02 Jun 2009 00:00:00 +020

Abstract: AbstractTransmit power in wireless cellular networks is a key degree of freedom in the management of interference, energy, and connectivity. Power control in both the uplink and downlink of a cellular network has been extensively studied, especially over the last 15 years, and some of the results have enabled the continuous evolution and significant impact of the digital cellular technology.This survey provides a comprehensive discussion of the models, algorithms, analysis, and methodologies in this vast and growing literature. It starts with a taxonomy of the wide range of power control problem formulations, and progresses from the basic formulation to more sophisticated ones. When transmit power is the only set of optimization variables, algorithms for fixed SIR are presented first, before turning to their robust versions and joint SIR and power optimization. This is followed by opportunistic and non-cooperative power control. Then joint control of power together with beamforming pattern, base station assignment, spectrum allocation, and transmit schedule is surveyed one-by-one.Throughout the survey, we highlight the use of mathematical language and tools in the study of power control, including optimization theory, control theory, game theory, and linear algebra. Practical implementations of some of the algorithms in operational networks are discussed in the concluding section. As illustrated by the open problems presented at the end of most chapters, in the area of power control in cellular networks, there are still many under-explored directions and unresolved issues that remain theoretically challenging and practically important.Suggested CitationMung Chiang, Prashanth Hande, Tian Lan and Chee Wei Tan (2008), "Power Control in Wireless Cellular Networks", Foundations and Trends® in Networking: Vol. 2: No. 4, pp 381-533. http://dx.doi.org/10.1561/1300000009 PubDate: Thu, 19 Jun 2008 00:00:00 +020

Abstract: AbstractNetwork coding is an elegant and novel technique introduced at the turn of the millennium to improve network throughput and performance. It is expected to be a critical technology for networks of the future. This tutorial deals with wireless and content distribution networks, considered to be the most likely applications of network coding, and it also reviews emerging applications of network coding such as network monitoring and management. Multiple unicasts, security, networks with unreliable links, and quantum networks are also addressed. The preceding companion deals with theoretical foundations of network coding.Suggested CitationChristina Fragouli and Emina Soljanin (2008), "Network Coding Applications", Foundations and Trends® in Networking: Vol. 2: No. 2, pp 135-269. http://dx.doi.org/10.1561/1300000013 PubDate: Sun, 08 Jun 2008 00:00:00 +020

Abstract: AbstractWe study how protocol design for various functionalities within a communication network architecture can be viewed as a distributed resource allocation problem. This involves understanding what resources are, how to allocate them fairly, and perhaps most importantly, how to achieve this goal in a distributed and stable fashion. We start with ideas of a centralized optimization framework and show how congestion control, routing and scheduling in wired and wireless networks can be thought of as fair resource allocation. We then move to the study of controllers that allow a decentralized solution of this problem. These controllers are the analytical equivalent of protocols in use on the Internet today, and we describe existing protocols as realizations of such controllers. The Internet is a dynamic system with feedback delays and flows that arrive and depart, which means that stability of the system cannot be taken for granted. We show how to incorporate stability into protocols, and thus, prevent undesirable network behavior. Finally, we consider a futuristic scenario where users are aware of the effects of their actions and try to game the system. We will see that the optimization framework is remarkably robust even to such gaming.Suggested CitationSrinivas Shakkottai and R. Srikant (2008), "Network Optimization and Control", Foundations and Trends® in Networking: Vol. 2: No. 3, pp 271-379. http://dx.doi.org/10.1561/1300000007 PubDate: Tue, 22 Jan 2008 00:00:00 +010

Abstract: AbstractNetwork coding is an elegant and novel technique introduced at the turn of the millennium to improve network throughput and performance. It is expected to be a critical technology for networks of the future. This tutorial addresses the first most natural questions one would ask about this new technique: how network coding works and what are its benefits, how network codes are designed and how much it costs to deploy networks implementing such codes, and finally, whether there are methods to deal with cycles and delay that are present in all real networks. A companion issue deals primarily with applications of network coding.Suggested CitationChristina Fragouli and Emina Soljanin (2007), "Network Coding Fundamentals", Foundations and Trends® in Networking: Vol. 2: No. 1, pp 1-133. http://dx.doi.org/10.1561/1300000003 PubDate: Sun, 10 Jun 2007 00:00:00 +020

Abstract: AbstractThis article reviews progress in cooperative communication networks. Our survey is by no means exhaustive. Instead, we assemble a representative sample of recent results to serve as a roadmap for the area. Our emphasis is on wireless networks, but many of the results apply to cooperation in wireline networks and mixed wireless/wireline networks. We intend our presentation to be a tutorial for the reader who is familiar with information theory concepts but has not actively followed the field. For the active researcher, this contribution should serve as a useful digest of significant results. This article is meant to encourage readers to find new ways to apply the ideas of network cooperation and should make the area sufficiently accessible to network designers to contribute to the advancement of networking practice.Suggested CitationGerhard Kramer, Ivana Marić and Roy D. Yates (2007), "Cooperative Communications", Foundations and Trends® in Networking: Vol. 1: No. 3–4, pp 271-425. http://dx.doi.org/10.1561/1300000004 PubDate: Fri, 01 Jun 2007 00:00:00 +020

Abstract: AbstractIn recent years there has been significant and increasing interest in ad hoc wireless networks. The design, analysis and deployment of such wireless networks necessitate a fundamental understanding of how much information transfer they can support, as well as what the appropriate architectures and protocols are for operating them. This monograph addresses these questions by presenting various models and results that quantify the information transport capability of wireless networks, as well as shed light on architecture design from a high level point of view. The models take into consideration important features such as the spatial distribution of nodes, strategies for sharing the wireless medium, the attenuation of signals with distance, and how information is to be transferred, whether it be by encoding, decoding, choice of power level, spatio-temporal scheduling of transmissions, choice of multi-hop routes, or other modalities of cooperation between nodes. An important aspect of the approach is to characterize how the information hauling capacity scales with the number of nodes in the network.The monograph begins by studying models of wireless networks based on current technology, which schedules concurrent transmissions to take account of interference, and then routes packets from their sources to destinations in a multi-hop fashion. An index of performance, called transport capacity, which is measured by the bit meters per second the network can convey in aggregate, is studied. For arbitrary networks, including those allowing for optimization of node locations, the scaling law for the transport capacity in terms of the number of nodes in the network is identified. For random networks, where nodes are randomly distributed, and source-destination pairs are randomly chosen, the scaling law for the maximum common throughput capacity that can be supported for all the source-destination pairs is characterized. The constructive procedure for obtaining the sharp lower bound gives insight into an order optimal architecture for wireless networks operating under a multi-hop strategy.To determine the ultimate limits on how much information wireless networks can carry requires an information theoretic treatment, and this is the subject of the second half of the monograph. Since wireless communication takes place over a shared medium, it allows more advanced operations in addition to multi-hop. To understand the limitations as well as possibilities for such information transfer, wireless networks are studied from a Shannon information-theoretic point of view, allowing any causal operation. Models that characterize how signals attenuate with distance, as well as multi-path fading, are introduced. Fundamental bounds on the transport capacity are established for both high and low attenuation regimes. The results show that the multi-hop transport scheme achieves the same order of scaling, though with a different pre-constant, as the information theoretically best possible, in the high attenuation regime. However, in the low attenuation regime, superlinear scaling may be possible through recourse to more advanced modes of cooperation between nodes. Techniques used in analyzing multi-antenna systems are also studied to characterize the scaling behavior of large wireless networks.Suggested CitationFeng Xue and P. R. Kumar (2006), "Scaling Laws for Ad Hoc Wireless Networks: An Information Theoretic Approach", Foundations and Trends® in Networking: Vol. 1: No. 2, pp 145-270. http://dx.doi.org/10.1561/1300000002 PubDate: Thu, 15 Jun 2006 00:00:00 +020

Abstract: Information flow in a telecommunication network is accomplished through the interaction of mechanisms at various design layers with the end goal of supporting the information exchange needs of the applications. In wireless networks in particular, the different layers interact in a nontrivial manner in order to support information transfer. In this text we will present abstract models that capture the cross-layer interaction from the physical to transport layer in wireless network architectures including cellular, ad-hoc and sensor networks as well as hybrid wireless-wireline. The model allows for arbitrary network topologies as well as traffic forwarding modes, including datagrams and virtual circuits. Furthermore the time varying nature of a wireless network, due either to fading channels or to changing connectivity due to mobility, is adequately captured in our model to allow for state dependent network control policies. Quantitative performance measures that capture the quality of service requirements in these systems depending on the supported applications are discussed, including throughput maximization, energy consumption minimization, rate utility function maximization as well as general performance functionals. Cross-layer control algorithms with optimal or suboptimal performance with respect to the above measures are presented and analyzed. A detailed exposition of the related analysis and design techniques is provided.Suggested CitationLeonidas Georgiadis, Michael J. Neely and Leandros Tassiulas (2006), "Resource Allocation and Cross-Layer Control in Wireless Networks", Foundations and Trends® in Networking: Vol. 1: No. 1, pp 1-144. http://dx.doi.org/10.1561/1300000001 PubDate: Sun, 30 Apr 2006 00:00:00 +020