Overlapping Coalition Formation Research Articles

A multi-responsibility–oriented coalition formation framework for dynamic task allocation in mobile–distributed multi-agent systems

In this article, we study a problem of dynamic task allocation with multiple agent responsibilities in distributed multi-agent systems. Agents in the research have two responsibilities, communication and task execution. Movements in agent task execution bring changes to the system network structure, which will affect the communication. Thus, agents need to be autonomous on communication network reconstruction for good performance on task execution. First, we analyze the relationships between the two responsibilities of agents. Then, we design a multi-responsibility–oriented coalition formation framework for dynamic task allocation with two parts, namely, task execution and self-adaptation communication. For the former part, we integrate our formerly proposed algorithm in the framework for task execution coalition formation. For the latter part, we develop a constrained Bayesian overlapping coalition game model to formulate the communication network. A task-allocation efficiency–oriented communication coalition utility function is defined to optimize a coalition structure for the constrained Bayesian overlapping coalition game model. Considering the geographical location dependence between the two responsibilities, we define constrained agent strategies to map agent strategies to potential location choices. Based on the abovementioned design, we propose a distributed location pruning self-adaptive algorithm for the constrained Bayesian overlapping coalition formation. Finally, we test the performance of our framework, multi-responsibility–oriented coalition formation framework, with simulation experiments. Experimental results demonstrate that the multi-responsibility oriented coalition formation framework performs better than the other two distributed algorithms on task completion rate (by over 9.4% and over 65% on average, respectively).

Distributed Resource Allocation for Network Slicing Over Licensed and Unlicensed Bands

Network slicing is considered one of the key enabling technologies for 5G due to its ability to customize and "slice" a common resource to support diverse services and verticals.This paper introduces a novel inter-operator network slicing framework in which multiple mobile network operators (MNOs) can coordinate and jointly slice their accessible spectrum resources in both licensed and unlicensed bands. For licensed band slicing, we propose an inter-operator spectrum aggregation method that allows two or more MNOs to cooperate and share their licensed bands to support a common set of service types. We then consider the sharing of unlicensed bands. Because all MNOs enjoy equal rights to accessing these bands, we introduce the concept of right sharing for MNOs to share and trade their spectrum access rights. We develop a {\em modified back-of-the-envelope (mBoE) method} for MNOs to evaluate their {\em Value-of-Rights (VoR)} when coexisting with other wireless technologies. A {\em network slicing game} based on the overlapping coalition formation game is formulated to investigate cooperation between MNOs. We prove that our proposed game always has at least one stable slicing structure that maximizes the social welfare. To implement our proposed framework without requiring MNOs to reveal private information to other MNOs, we develop a distributed algorithm called D-ADMM-PVS. Performance evaluation of our proposed framework is provided using a discrete-event simulator that is driven by real MNO deployment scenarios based on over 400 base station locations deployed by two primary cellular operators in the city of Dublin.Numerical results show that our proposed framework can almost double the capacity for all supported services for each MNO in an urban setting.

Overlapping Coalition-Based Resource and Power Allocation for Enhanced Performance of Underlaying D2D Communication

Device-to-Device (D2D) communication is seen as a promising technology to offload exponentially increasing cellular data traffic. This also enhances spectral and energy efficiency of the cellular network. However, co-channel interference restricts the potential gain of Underlay-D2D (U-D2D) communication technology. In this paper, we propose a novel resource allocation scheme coupled with distributed power control strategy to reduce co-channel interference and improve overall system sum rate. Resource allocation is based on overlapping coalition formation game model. Overlapping coalitions allow a single D2D pair to utilize multiple resource blocks, which provides enhanced transmission bandwidth per user. But, this improved bandwidth is achieved at the cost of increased co-channel interference. The proposed scheme mitigates this problem by distributed control of D2D transmit power in accordance with the interference sensed on each resource block allocated for that particular D2D pair. It is shown through numerical results that there is a significant improvement in overall U-D2D system performance in terms of system sum rate and D2D transmission ratio in comparison with other existing techniques.

Sequentially Distributed Coalition Formation Game for Throughput Maximization in C-RANs

Cloud radio access network (C-RAN) has been proposed as a solution to reducing the huge cost of network upgrade while providing the spectral and energy efficiency needed for the new generation cellular networks. In order to reduce the interference that occur in C-RAN and maximize throughput, this paper proposes a sequentially distributed coalition formation (SDCF) game in which players, in this case the remote radio heads (RRHs), can sequentially join multiple coalitions to maximize their throughput. Contrary to overlapping coalition formation (OCF) game where players contribute fractions of their limited resources to different coalitions, the SDCF game offers better stability by allowing sequential coalition formation depending on the availability of resources and therefore providing a balance between efficient spectrum use and interference management. An algorithm for the proposed model is developed based on the merge-only method. The performance of the proposed algorithm in terms of stability, complexity and convergence to final coalition structure is also investigated. Simulation results show that the proposed SDCF game did not only maximize the throughput in the C-RAN, but it also shows better performances and larger capabilities to manage interference with increasing number of RRHs compared to existing methods.

Socially Aware Secrecy-Ensured Resource Allocation in D2D Underlay Communication: An Overlapping Coalitional Game Scheme

With the popularity of proximity-based services, device-to-device (D2D) communication underlaying cellular networks is a promising technology to cope with the growing demands by improving network resource utilization. However, the wireless communication's broadcast nature is vulnerable to eavesdropping, and thus, ensuring a secrecy communication for both cellular user equipments (CUEs) and D2D pairs in an underlay network is a challenging issue. We investigate the problem of physical-layer secure transmission jointly with resource allocation in D2D communications. Different from existing works, we framed overlapping (partial) coalitional game where each D2D pair can access multiple CUEs' spectral resources. Moreover, the multiple D2D pairs can share single CUE subchannel in multiple eavesdroppers scenario to ensure information security for both CUEs and D2D pairs and to maximize system sum rate in a socially aware D2D network. We incorporate the mutual interference and propose different transmission modes for a secrecy-ensured resource allocation-based overlapping coalition formation scheme with transferable utility to obtain a final stable partition. We further prove the proposed algorithm stability, convergence, and computational complexity. Both analytical and numerical results demonstrate the effectiveness of our proposed scheme, which ensures a system-wide security and at the same time improves the performance by maximizing the system sum rate.

Overlapping Coalition Formation Games for Joint Interference Management and Resource Allocation in D2D Communications

In this paper, an overlapping coalition formation game is proposed to conduct joint interference management and resource allocation in device-to-device (D2D) communications. We aim at improving the sum rate of all D2D links in D2D communications underlying cellular network without sacrificing the quality of service of each cellular user (CU) and D2D link. First, based on the cross-tier interference level between CUs and D2D links, each D2D link selects multiple best resource blocks (RBs) to reuse. Then, by dividing the user equipments (i.e., CU and D2D links) which share the same RB into one coalition, an initial overlapping coalitional structure is formed. A cooperative game with overlapping coalitions is further proposed to maximize the system utility in terms of sum rate of all D2D links. Finally, the characteristic analysis of the proposed algorithm is provided to validate that the user equipments can cooperate to form a stable and most beneficial coalitional structure with overlapping coalitions. Simulation results show that the proposed overlapping coalition formation game achieves a better performance compared with other existing schemes.

Overlapping Coalition Formation Game for Resource Allocation in Network Coding Aided D2D Communications

Due to spectrum sharing, device-to-device (D2D) communications underlaying cellular networks enhance system capacity significantly that benefits services of local area. On the other hand, network coding enables highly efficient cooperation, which increases the system capacity through code-and-forward mechanism. It is a challenging problem that how to allocate resource in the network coding aided cooperative D2D communications. In this paper, we first design a network coding aided cooperative diversity scheme for D2D communication, and derive the system transmission rate with the consideration of interference. Then, we formulate the problem of joint spectrum resource allocation and relay selection as an overlapping coalition formation game, where one relay is able to serve multiple coalitions to increase the system capacity. For each coalition, maximum bipartite graph matching model is established to select the optimal relay to achieve the maximum transmission rate. Finally, to solve the formulated game problem, we propose a distributed algorithm based on switch operations with low computation complexity. Extensive numerical results demonstrate that our solution increases the system transmission rate by about 30-40 percent without bringing extra computation complexity, compared with other state-of-the-art schemes.

Cooperative Management in Full-Truckload and Less-Than-Truckload Vehicle System

In cooperative logistics, shippers can cooperate to improve efficiency and reduce the cost of product/package delivery services. In this paper, we consider the resource, i.e., vehicles, sharing problem to serve customers in the cooperative logistics environment. In the environment, small shippers cooperate by forming a coalition to create a vehicle pool and to allow sharing of their own vehicles with each other. The vehicles in the pool are used to deliver packages to customers. To minimize the delivery cost to the shippers, we propose a framework for the capacitated vehicle routing problem with time windows. The framework is composed of joint vehicle allocation, cost management, and overlapping coalition formation among shippers. For vehicle allocation, we formulate and solve optimization models to determine the number of vehicles and their delivery routes to meet customer demand and service time. The uncertainty of customer demand is taken into consideration. For sharing the delivery cost generated in the vehicle pool, i.e., cost management, among the cooperative shippers in a coalition, we apply the concept of Myerson value from the cooperative game theory as a solution. Based on the cost, the shippers then decide whether to cooperate and share the vehicles or not. The performance evaluation based on the test and actual road networks clearly shows the benefits of the proposed framework.

Game Theoretic Analysis of Cooperative Message Forwarding in Opportunistic Mobile Networks

In cooperative communication, a set of players forming a coalition ensures communal behavior among themselves by helping one another in message forwarding. Opportunistic mobile networks (OMNs) require multihop communications for transferring messages from the source to the destination nodes. However, noncooperative nodes only forward their own messages to others, and drop others' messages upon receiving them. So, the message delivery overhead increases in OMN. For minimizing the overhead and maximizing the delivery rate, we propose two coalition-based cooperative schemes: 1) simple coalition formation (SCF) and 2) overlapping coalition formation (OCF) game. In SCF, we consider the presence of a central information center, whereas OCF is a fully distributed scheme. In SCF, coalitions are disjoint, whereas in OCF, a node may be the member of multiple coalitions at the same time. All nodes in a coalition help each other cooperatively by forwarding group messages to the intermediate or destination nodes. The goal of the nodes is to achieve high success rate in delivering messages. The proposed SCF scheme is cohesive, in which disjoint coalitions always combine to form grand coalition. In OCF, a node reaches a stable grand coalition when all the nodes of the OMN are members of overlapping coalition of the node. No node gains by deviating from the grand coalition in SCF and OCF. Simulation results based on synthetic mobility model and real-life traces show that the message delivery ratio of OMNs increase by up to 67%, as compared to the noncooperative scenario. Moreover, the message overhead ratio using the proposed coalition-based schemes reduces by up to about (1/3)rd of that of the noncooperative communication scheme.

Toward Cooperation by Carrier Aggregation in Heterogeneous Networks: A Hierarchical Game Approach

This paper studies the resource-allocation problem for a heterogeneous network (HetNet) in which the spectrum owned by a macrocell operator (MCO) can be shared by both unlicensed users (UUs) and licensed users (LUs). We formulate a novel hierarchical game theoretic framework to jointly optimize the transmit powers and subband allocations of the UUs and the pricing strategies of the MCO. In our framework, an overlapping coalition formation (OCF) game has been introduced to model the cooperative behaviors of the UUs. We then integrate this OCF game into a Stackelberg game-based hierarchical framework. We prove that the core of our proposed OCF game is nonempty and introduce an optimal subband-allocation scheme for UUs. A simple distributed algorithm is proposed for UUs to autonomously form an optimal coalition formation (CF) structure. The Stackelberg equilibrium (SE) of the proposed hierarchical game is derived, and its uniqueness and optimality are proved. A distributed joint optimization algorithm is also proposed to approach the SE of the game with limited information exchanges between the MCO and the UUs.

Overlapping Coalition Formation Game BasedOpportunistic Cooperative Localization Schemefor Wireless Networks

Cooperative localization has emerged as a promising technique which can complement or even replace global positioning systems (GPS) in many practical scenarios, such as GPS-denied environments. In this paper, we concentrate on the distributed cooperative localization design. The conventional distributed cooperative localization approaches usually yield high computational complexity and communication overhead, due to the lack of an efficient link selection mechanism. For this purpose, we propose a novel concept named opportunistic cooperative localization, based on which each agent is able to select the most informative links rather than utilize all the possible links in a distributed, self-organized, and self-optimized manner. To achieve effective opportunistic selection, overlapping coalition formation (OCF) game is employed. In addition, we also provide an optimized terminating criterion, based on which the agents will be able to know whether and when they are well localized, and thus can terminate their localization procedure efficiently. Through simulations, we observe that by virtue of the proposed OCF game based opportunistic cooperative localization scheme along with the provided terminating criterion, the limitations of conventional distributed cooperative localization can be alleviated at the cost of negligible performance degradation.

Collaborative Smartphone Sensing Using Overlapping Coalition Formation Games

With the rapid growth of sensor technology, smartphone sensing has become an effective approach to improve the quality of smartphone applications. However, due to time-varying wireless channels and lack of incentives for the users to participate, the quality and quantity of the data uploaded by the smartphone users are not always satisfying. In this paper, we consider a smartphone sensing system in which a platform publicizes multiple tasks, and the smartphone users choose a set of tasks to participate in. In the traditional non-cooperative approach with incentives, each smartphone user gets rewards from the platform as an independent individual and the limit of the wireless channel resources is often omitted. To tackle this problem, we introduce a novel cooperative approach with an overlapping coalition formation game (OCF-game) model, in which the smartphone users can cooperate with each other to form the overlapping coalitions for different sensing tasks. We also utilize a centralized case to describe the upper bound of the system sensing performance. Simulation results show that the cooperative approach achieves a better performance than the non-cooperative one in various situations.

An Overlapping Coalitional Game for Cooperative Spectrum Sensing and Access in Cognitive Radio Networks

Cognitive radio networks (CRNs) provide an effective solution to address the increasing demand for spectrum resources. The cooperation among secondary users (SUs) improves the sensing performance and spectrum efficiency. In this paper, we study the traffic-demand-based cooperation strategy of SUs in multichannel CRNs, in which each SU makes its own cooperative sensing decision according to its traffic demand. When an SU has high traffic demand, it can choose to sense multiple channels in the sensing period and obtain more chances to use spectrum resources. If an SU has no data to transmit, it can choose not to perform spectrum sensing. We formulate this problem as a nontransferable utility (NTU) overlapping coalitional game. In this game, each SU implements a cooperation strategy according to its expected payoff, which takes into account the expected throughput and energy efficiency. We propose two different algorithms, namely, an overlapping coalition formation (OCF) algorithm and a sequential coalition formation (SCF) algorithm, to obtain a coalition structure. The OCF algorithm guarantees that the coalition structure is stable, whereas the SCF algorithm has lower computational complexity and less information exchange among SUs. Moreover, when being assigned a certain channel, SU implements an adaptive transmission power control scheme to further improve its energy efficiency. Simulation results show that our proposed algorithms achieve a higher aggregate throughput than the disjoint coalition formation algorithm from the literature, where each SU can join only one coalition.

VERACITY: Overlapping Coalition Formation-Based Double Auction for Heterogeneous Demand and Spectrum Reusability

Spectrum auction is one of the most effective solutions to allocate the spectrum resource following the market rules and has attracted much attention from both academia and industry. However, most of the existing studies assume that the spectrum buyers’ demands are homogeneous and the interference relationship is fixed without any change with the variation of spectrum. Furthermore, the economical efficiency of auction outcome has not drawn enough attention. That motivates us to design an auction scheme to jointly consider the multi-demand of buyers, heterogeneous spectrum, and economical efficiency. In this paper, we propose a novel overlapping coalition formation-based double auction, called VERACITY, to address this problem. The auctioneer groups the conflict free buyers into the same coalition and allows a buyer to join multiple coalitions based on the heterogeneous demand. Dynamic overlapping coalition formation implemented by the auctioneer is to find the approximately optimal coalition structure corresponding to the economical efficiency outcome, i.e., maximizing the social welfare. Furthermore, we prove that VERACITY is individually rational, budget balanced, truthful, and economically efficient. Simulation results are presented to show the convergence and effectiveness of the proposed VERACITY.

Overlapping coalition formation games for emerging communication networks

Modern cellular networks are witnessing an unprecedented evolution from classical centralized and homogenous architectures into a mix of various technologies, in which the network devices are densely and randomly deployed in a decentralized and heterogenous architecture. This shift in network architecture requires network devices to become more autonomous and, potentially, cooperate with one another. Such cooperation can, for example, take place between interfering small access points that seek to coordinate their radio resource allocation, nearby single-antenna users that can cooperatively perform virtual MIMO communications, or even unlicensed users that wish to cooperatively sense the spectrum of licensed users. Such cooperative mechanisms involve the simultaneous sharing and distribution of resources among a number of overlapping cooperative groups or coalitions. In this article, a novel mathematical framework from cooperative games, dubbed overlapping coalition formation games (OCF games), is introduced to model and solve such cooperative scenarios. First, the concepts of OCF games are presented, and then several algorithmic aspects are studied for two main classes of OCF games. Subsequently, two example applications, interference management and cooperative spectrum sensing, are discussed in detail to show how the proposed models and algorithms can be used in future scenarios of wireless systems. Finally, we conclude by providing an overview on future directions and applications of OCF games.

Overlapping coalition formation games based interference coordination for D2D underlaying LTE-A networks

In the device-to-device (D2D) underlaying LTE-Advanced (LTE-A) systems, unlike the existing works which formulate the resources sharing problem as a disjoint coalition formation game, in this letter we propose a novel overlapping coalition formation game (OCFG) based scheme to coordinate the interference between these two subsystems. By sharing uplink spectrums, in this game each D2D pair is allowed to join multiple coalitions simultaneously to improve the spectral efficiency and maximize the system utility. The merge-and-split rule is designed to adapt to the dynamic environment and a discrete-time Markov chain based analysis is utilized to present the stability. Compared with traditional methods, simulations demonstrate the significant performance enhancement of the proposed algorithm in terms of the complexity and D2D system sum throughput.

Overlapping coalition formation games‐based resource allocation for device‐to‐device communication in LTE‐A network

AbstractIn the long‐term evolution‐advanced system, device‐to‐device (D2D) communication brings many significant benefits, such as low power consumption, low delay, high bit rates and efficient frequency utilisation. However, these potential advantages hinge on the intelligent resource allocation approach between D2D user equipments (DUEs) and cellular user equipments (CUEs). Different from existing work that focused on the scenario that one CUE shares spectrums with one D2D pair and thus disjoint groups are formed to use spectrums, in our paper, we proposed a coalition formulation game with overlapping coalitions. In this game, we model the resource sharing problem as a transferable coalition formation game where there exists intersection among these coalitions and the DUEs can make a decision to join or leave a coalition according to the merge‐and‐split rule. Consequently, not only one D2D pair can employ the same resource with multiple CUEs but also the channel of one CUE can be allocated to multiple D2D pairs in order to maximise the frequency efficiency and the system sum throughput. In particular, we consider the practical case and study the effect that only imperfect channel state information (CSI) can be obtained on the stable coalition formation game. A discrete‐time Markov chain‐based analysis is presented to obtain the stable coalition structure, and the complexity of employing this scheme is evaluated. Extensive numerical results show that the proposed overlapping coalition formulation game‐based scheme results in better performance compared to the traditional existing methods even in the imperfect CSI scenarios. Copyright © 2015 John Wiley & Sons, Ltd.

A Bayesian Overlapping Coalition Formation Game for Device-to-Device Spectrum Sharing in Cellular Networks

We consider the spectrum sharing problem between a set of device-to-device (D2D) links and multiple co-located cellular networks. Each cellular network is controlled by an operator which can provide service to a number of subscribers. Each D2D link can either access a sub-band occupied by a cellular subscriber or obtain an empty sub-band for its exclusive use. We introduce a new spectrum sharing mode for D2D communications in cellular networks by allowing two or more D2D links with exclusive use of sub-bands to share their sub-bands with each other without consulting the operators. We establish a new game theoretic model called Bayesian non-transferable utility overlapping coalition formation (BOCF) game. We show that our proposed game can be used to model and analyze the above spectrum sharing problem. However, we observe that the core of the BOCF game can be empty, and we derive a sufficient condition for which the core is non-empty. We propose a hierarchical matching algorithm which can detect whether the sufficient condition is satisfied and, if it is satisfied, achieve a stable and unique matching structure which coincides with the overlapping coalition agreement profile in the core of the BOCF game.

Distributed Cooperative Sensing in Cognitive Radio Networks: An Overlapping Coalition Formation Approach

Cooperative spectrum sensing has been shown to yield a significant performance improvement in cognitive radio networks. In this paper, we consider distributed cooperative sensing (DCS) in which secondary users (SUs) exchange data with one another instead of reporting to a common fusion center. In most existing DCS algorithms, the SUs are grouped into disjoint cooperative groups or coalitions, and within each coalition the local sensing data is exchanged. However, these schemes do not account for the possibility that an SU can be involved in multiple cooperative coalitions thus forming overlapping coalitions. Here, we address this problem using novel techniques from a class of cooperative games, known as overlapping coalition formation games, and based on the game model, we propose a distributed DCS algorithm in which the SUs self-organize into a desirable network structure with overlapping coalitions. Simulation results show that the proposed overlapping algorithm yields significant performance improvements, decreasing the total error probability up to 25% in the Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> + Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> criterion, the missed detection probability up to 20% in the Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> /Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> criterion, the overhead up to 80%, and the total report number up to 10%, compared with the state-of-the-art non-overlapping algorithm.

Arbitration and Stability in Cooperative Games with Overlapping Coalitions

Overlapping Coalition Formation (OCF) games, introduced by Chalkiadakis, Elkind, Markakis, Polukarov and Jennings in 2010, are cooperative games where players can simultaneously participate in several coalitions. Capturing the notion of stability in OCF games is a difficult task:deviating players may continue to contribute resources to joint projects with non-deviators, and the crucial question is what payoffs the deviators expect to receive from such projects. Chalkiadakis et al. introduce three stability concepts for OCF games---the conservative core, the refined core, and the optimistic core---that are based on different answers to this question. In this paper, we propose a unified framework for the study of stability in the OCF setting, which encompasses the stability concepts considered by Chalkiadakis et al. as well as a wide variety of alternative stability concepts. Our approach is based on the notion of arbitration functions, which determine the payoff obtained by the deviators, given their deviation and the current allocation of resources. We provide a characterization of stable outcomes under arbitration. We then conduct an in-depth study of four types of arbitration functions, which correspond to four notions of the core; these include the three notions of the core considered by Chalkiadakis et al. Our results complement those of Chalkiadakis et al. and answer questions left open by their work. In particular, we show that OCF games with the conservative arbitration function are essentially equivalent to non-OCF games, by relating the conservative core of an OCF game to the core of a non-overlapping cooperative game, and use this result to obtain a strictly weaker sufficient condition for conservative core non-emptiness than the one given by Chalkiadakis et al.