Coalition Formation Games for Distributed Cooperation Among Roadside Units in Vehicular Networks

Vehicle-to-roadside (V2R) communications enable vehicular networks to support a wide range of applications for enhancing the efficiency of road transportation. While existing work focused on non-cooperative techniques for V2R communications between vehicles and roadside units (RSUs), this paper investigates novel cooperative strategies among the RSUs in a vehicular network. We propose a scheme whereby, through cooperation, the RSUs in a vehicular network can coordinate the classes of data being transmitted through V2R communications links to the vehicles. This scheme improves the diversity of the information circulating in the network while exploiting the underlying content-sharing vehicle-to-vehicle communication network. We model the problem as a coalition formation game with transferable utility and we propose an algorithm for forming coalitions among the RSUs. For coalition formation, each RSU can take an individual decision to join or leave a coalition, depending on its utility which accounts for the generated revenues and the costs for coalition coordination. We show that the RSUs can self-organize into a Nash-stable partition and adapt this partition to environmental changes. Simulation results show that, depending on different scenarios, coalition formation presents a performance improvement, in terms of the average payoff per RSU, ranging between 20.5% and 33.2%, relative to the non-cooperative case.Comment: accepted and to appear in IEEE Journal on Selected Areas in Communications (JSAC), Special issue on Vehicular Communications and Network

A Taxonomy for Congestion Control Algorithms in Vehicular Ad Hoc Networks

One of the main criteria in Vehicular Ad hoc Networks (VANETs) that has attracted the researchers' consideration is congestion control. Accordingly, many algorithms have been proposed to alleviate the congestion problem, although it is hard to find an appropriate algorithm for applications and safety messages among them. Safety messages encompass beacons and event-driven messages. Delay and reliability are essential requirements for event-driven messages. In crowded networks where beacon messages are broadcasted at a high number of frequencies by many vehicles, the Control Channel (CCH), which used for beacons sending, will be easily congested. On the other hand, to guarantee the reliability and timely delivery of event-driven messages, having a congestion free control channel is a necessity. Thus, consideration of this study is given to find a solution for the congestion problem in VANETs by taking a comprehensive look at the existent congestion control algorithms. In addition, the taxonomy for congestion control algorithms in VANETs is presented based on three classes, namely, proactive, reactive and hybrid. Finally, we have found the criteria in which fulfill prerequisite of a good congestion control algorithm

Wireless industrial monitoring and control networks: the journey so far and the road ahead

While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks

Algorithms on Wireless Network Coding

Network coding is a novel technique that has a significant potential to improve throughput, robustness and security of both wireless and wireline networks. With network coding the intermediate nodes in the network have the capability to combine multiple incoming packets and forward the resulting packets over their outgoing links. This technique has a significant advantage over traditional methods such as forwarding and duplication of packets. Recently, the network coding technique has attracted a significant interest from the research community. In this dissertation, we address a number of wireless network coding problems. In particular, our work focuses on the Cooperative Data Exchange (CDE), one of the central problems in wireless network coding. In Cooperative Data Exchange, a group of clients that have a prior side information about a set of packets use a shared broadcast channel to recover the missing packets from the set. We focus on different variations of the problem, including data exchange in the presence of passive and active adversaries, data exchange subject to deadlines, as well as serving clients of different priority classes. For each variation, we analyze the complexity of the problem and present exact or approximation algorithms for its solution. We show that this set of problem is very rich and has deep connections to different areas of coding theory, algebraic geometry, and information theory

Smart Grid Communications: Overview of Research Challenges, Solutions, and Standardization Activities

Optimization of energy consumption in future intelligent energy networks (or Smart Grids) will be based on grid-integrated near-real-time communications between various grid elements in generation, transmission, distribution and loads. This paper discusses some of the challenges and opportunities of communications research in the areas of smart grid and smart metering. In particular, we focus on some of the key communications challenges for realizing interoperable and future-proof smart grid/metering networks, smart grid security and privacy, and how some of the existing networking technologies can be applied to energy management. Finally, we also discuss the coordinated standardization efforts in Europe to harmonize communications standards and protocols.Comment: To be published in IEEE Communications Surveys and Tutorial

Cooperative Data Exchange based on MDS Codes

The cooperative data exchange problem is studied for the fully connected network. In this problem, each node initially only possesses a subset of the $K$ packets making up the file. Nodes make broadcast transmissions that are received by all other nodes. The goal is for each node to recover the full file. In this paper, we present a polynomial-time deterministic algorithm to compute the optimal (i.e., minimal) number of required broadcast transmissions and to determine the precise transmissions to be made by the nodes. A particular feature of our approach is that {\it each} of the $K-d$ transmissions is a linear combination of {\it exactly} $d+1$ packets, and we show how to optimally choose the value of $d.$ We also show how the coefficients of these linear combinations can be chosen by leveraging a connection to Maximum Distance Separable (MDS) codes. Moreover, we show that our method can be used to solve cooperative data exchange problems with weighted cost as well as the so-called successive local omniscience problem.Comment: 21 pages, 1 figur

Successive Local and Successive Global Omniscience

This paper considers two generalizations of the cooperative data exchange problem, referred to as the successive local omniscience (SLO) and the successive global omniscience (SGO). The users are divided into $\ell$ nested sub-groups. Each user initially knows a subset of packets in a ground set $X$ of size $k$, and all users wish to learn all packets in $X$. The users exchange their packets by broadcasting coded or uncoded packets. In SLO or SGO, in the $l$th ($1\leq l\leq \ell$) round of transmissions, the $l$th smallest sub-group of users need to learn all packets they collectively hold or all packets in $X$, respectively. The problem is to find the minimum sum-rate (i.e., the total transmission rate by all users) for each round, subject to minimizing the sum-rate for the previous round. To solve this problem, we use a linear-programming approach. For the cases in which the packets are randomly distributed among users, we construct a system of linear equations whose solution characterizes the minimum sum-rate for each round with high probability as $k$ tends to infinity. Moreover, for the special case of two nested groups, we derive closed-form expressions, which hold with high probability as $k$ tends to infinity, for the minimum sum-rate for each round.Comment: Accepted for publication in Proc. ISIT 201

A Comparison of Traditional and Newly Emerging Forms of Cooperative Capitalization

This paper compares the traditional forms of capitalization used by American co-ops to newly emerging forms. It is based on an in-depth review of several case co-ops. A broad framework is provided that may be beneficial in more extensive studies of capitalization practices of cooperatives and similar organizations. It is divided into three parts. Part One outlines the alternative capitalization forms being used by cooperatives and their antecedents, where conversions to other structures and forms have occurred. Two basic capitalization forms have been used by cooperatives: traditional (open) and new generation (closed). Cooperatives using both forms have elected to add new capitalization features, such as use of publicly listed stock, or have elected to convert to different forms, such as an LLC or a C corporation. Several perceived advantages have motivated these changes besides the traditional advantages utilized by cooperative corporations, limited liability and single taxation. They include access to capital, liquidity and appreciability of stock. Part Two provides a brief description of the nature and experience of several modern cooperative organizations using the framework presented in Part One. The descriptions are based on in-depth case studies. The case study selections are from a broad cross-section of cooperatives that include the following: (1) Mid-Kansas Cooperative (traditional, centralized, local grain marketing and farm supply using only internally generated equity); (2) Land O'Lakes (traditional, centralized and federated, regional dairy marketing and processing and farm supply using only internally generated equity and registered debt financing); (3) CHS Cooperatives (traditional, primarily federated, regional grain marketing and processing and farm supply, with the recent addition of publicly listed preferred stock); and (4) U.S. Premium Beef (new generation, centralized, regional beef processing using closely held but tradeable common stock and proposal to convert to an LLC with member and non-member tradeable stock). In addition brief mention is made of other cooperatives including (5) Dakota Growers Pasta (new generation, centralized, regional durum wheat processing with recent conversion to C corporation); (6) South Dakota Soybean Processing (new generation, centralized regional soybean processing with conversion to LLC); (7) Pro-Fac and Birds Eye Foods (new generation centralized regional frozen vegetable processing with publicly listed stock and transition of processing entity, Birds Eye, to majority ownership by investor-oriented partner likely to exit through an IPO) and (8) Gold Kist (traditional, centralized regional poultry processing with proposed conversion to publicly traded C corporation). Part Three will briefly outline some of the challenges facing cooperatives in the future with reference to capitalization.Financial Economics, Agribusiness,