Browsing by Author "Song, Lingyang"
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Item Coalitional Games with Overlapping Coalitions for Interference Management in Small Cell Networks(IEEE Transactions on Wireless Communications, 4/4/2014) Zhang, Zengfeng; Song, Lingyang; Han, Zhu; Saad, WalidIn this paper, we study the problem of cooperative interference management in an OFDMA two-tier small cell network. In particular, we propose a novel approach for allowing the small cells to cooperate, so as to optimize their sum-rate, while cooperatively satisfying their maximum transmit power constraints. Unlike existing work which assumes that only disjoint groups of cooperative small cells can emerge, we formulate the small cells' cooperation problem as a coalition formation game with overlapping coalitions. In this game, each small cell base station can choose to participate in one or more cooperative groups (or coalitions) simultaneously, so as to optimize the tradeoff between the benefits and costs associated with cooperation. We study the properties of the proposed overlapping coalition formation game and we show that it exhibits negative externalities due to interference. Then, we propose a novel decentralized algorithm that allows the small cell base stations to interact and self-organize into a stable overlapping coalitional structure. Simulation results show that the proposed algorithm results in a notable performance advantage in terms of the total system sum-rate, relative to the noncooperative case and the classical algorithms for coalitional games with non-overlapping coalitions.Item Coalitional Graph Games for Popular Content Distribution in Cognitive Radio VANETs(IEEE Transactions on Vehicular Technology, 2/6/2013) Wang, Tianyu; Song, Lingyang; Han, ZhuPopular content distribution is one of the key services provided by vehicular ad hoc networks (VANETs), in which a popular file is broadcast by roadside units (RSUs) to the onboard units (OBUs) driving through a particular area. Due to fast speeds and deep fading, some file packets might be lost during the vehicle-to-roadside (V2R) broadcasting stage. In this paper, we propose a peer-to-peer (P2P) approach to allow the OBUs to exchange data and complement the missing packets. Specifically, we introduce a coalitional graph game to model the cooperation among OBUs and propose a coalition formation algorithm to implement the P2P approach. Moreover, cognitive radio (CR) is utilized for vehicle-to-vehicle (V2V) transmissions so that the P2P approach does not require additional bandwidth. Simulation results show that the proposed approach performs better under various conditions, relative to the noncooperative approach, in which the OBUs share no information and simply respond to any data request from other OBUs.Item Collaborative Smartphone Sensing Using Overlapping Coalition Formation Games(IEEE Transactions on Mobile Computing, 3/3/2016) Di, Boya; Wang, Tianyu; Song, Lingyang; Han, ZhuWith 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.Item Dynamic Popular Content Distribution in Vehicular Networks using Coalition Formation Games(IEEE Journal on Selected Areas in Communications, 7/2/2013) Wang, Tianyu; Song, Lingyang; Han, Zhu; Jiao, BingliDriven by both safety concerns and commercial interests, vehicular ad hoc networks (VANETs) have recently received considerable attentions. In this paper, we address popular content distribution (PCD) in VANETs, in which one large popular file is downloaded from a stationary roadside unit (RSU), by a group of on-board units (OBUs) driving through an area of interest (AoI) along a highway. Due to high speeds of vehicles and deep fadings of vehicle-to-roadside (V2R) channels, some of the vehicles may not finish downloading the entire file but only possess several pieces of it. To successfully send a full copy to each OBU, we propose a cooperative approach based on coalition formation games, in which OBUs exchange their possessed pieces by broadcasting to and receiving from their neighbors. Simulation results show that our proposed approach presents a considerable performance improvement relative to the non-cooperative approach, in which the OBUs broadcast randomly selected pieces to their neighbors as along as the spectrum is detected to be unoccupied.Item Efficiency Resource Allocation for Device-to-Device Underlay Communication Systems: A Reverse Iterative Combinatorial Auction Based Approach(IEEE Journal on Selected Areas in Communications, 8/26/2013) Xu, Chen; Song, Lingyang; Han, Zhu; Zhao, Qun; Wang, Xiaoli; Cheng, Xiang; Jaio, BingliPeer-to-peer communication has been recently considered as a popular issue for local area services. An innovative resource allocation scheme is proposed to improve the performance of mobile peer-to-peer, i.e., device-to-device (D2D), communications as an underlay in the downlink (DL) cellular networks. To optimize the system sum rate over the resource sharing of both D2D and cellular modes, we introduce a reverse iterative combinatorial auction as the allocation mechanism. In the auction, all the spectrum resources are considered as a set of resource units, which as bidders compete to obtain business while the packages of the D2D pairs are auctioned off as goods in each auction round. We first formulate the valuation of each resource unit, as a basis of the proposed auction. And then a detailed non-monotonic descending price auction algorithm is explained depending on the utility function that accounts for the channel gain from D2D and the costs for the system. Further, we prove that the proposed auction-based scheme is cheat-proof, and converges in a finite number of iteration rounds. We explain non-monotonicity in the price update process and show lower complexity compared to a traditional combinatorial allocation. The simulation results demonstrate that the algorithm efficiently leads to a good performance on the system sum rate.Item Energy-Efficient Resource Allocation for Device-to-Device Underlay Communication(IEEE Transactions on Wireless Communications, 12/10/2014) Wang, Feiran; Xu, Chen; Song, Lingyang; Han, ZhuDevice-to-device (D2D) communication underlaying cellular networks is expected to bring significant benefits for utilizing resources, improving user throughput, and extending the battery life of user equipment. However, the allocation of radio and power resources to D2D communication needs elaborate coordination, as D2D communication can cause interference to cellular communication. In this paper, we study joint channel and power allocation to improve the energy efficiency of user equipments. To solve the problem efficiently, we introduce an iterative combinatorial auction algorithm, where the D2D users are considered bidders that compete for channel resources and the cellular network is treated as the auctioneer. We also analyze important properties of D2D underlay communication and present numerical simulations to verify the proposed algorithm.Item Full duplex cognitive radio: a new design paradigm for enhancing spectrum usage(IEEE Communications Magazine, 5/14/2015) Liao, Yun; Song, Lingyang; Han, Zhu; Li, YonghuiWith the rapid growth of demand for ever increasing data rates, spectrum resources have become more and more scarce. As a promising technique to increase the efficiency of the spectrum utilization, cognitive radio has great potential to meet such a requirement by allowing unlicensed users to coexist in licensed bands. In conventional CR systems, spectrum sensing is performed at the beginning of each time slot before data transmission. Unfortunately, this results in two major problems: transmission time reduction due to sensing, and sensing accuracy impairment due to data transmission. To tackle these problems, in this article we present a new design paradigm for future CR by exploring full duplex techniques to achieve simultaneous spectrum sensing and data transmission. With FD radios equipped at secondary users (SUs), the SUs can simultaneously sense and access the vacant spectrum, and thus significantly improve sensing performance while increasing data transmission efficiency. The aim of this article is to transform the promising conceptual framework into a practical wireless network design by addressing a diverse set of challenges such as protocol design and theoretical analysis. Several application scenarios with FD-enabled CR are elaborated, and key open research directions and novel algorithms in these systems are discussed.Item Full-Duplex MAC Protocol Design and Analysis(IEEE Communications Letters, 4/20/2015) Liao, Yun; Bian, Kaigui; Song, Lingyang; Han, ZhuThe idea of in-band full-duplex (FD) communications has been revived in recent years owing to the significant progress in the self-interference cancellation and hardware design techniques, offering the potential to double spectral efficiency. The adaptations in upper layers are highly demanded in the design of FD communication systems. In this letter, we propose a novel medium access control (MAC) using FD techniques that allows transmitters to monitor the channel usage while transmitting, and backoff as soon as collision happens. Analytical saturation throughput of the FD-MAC protocol is derived with the consideration of imperfect sensing brought by residual self-interference (RSI) in the PHY layer. Both analytical and simulation results indicate that the normalized saturation throughput of the proposed FD-MAC can significantly outperforms conventional CSMA/CA under various network conditions.Item Game Theoretic Approaches to Massive Data Processing in Wireless Networks(IEEE Wireless Communications, 2/28/2018) Zheng, Zijie; Song, Lingyang; Han, Zhu; Li, Geoffrey Ye; Poor, H. VincentWireless communication networks are becoming highly virtualized with two-layer hierarchies, in which controllers at the upper layer with tasks to achieve can ask a large number of agents at the lower layer to help realize computation, storage, and transmission functions. Through offloading data processing to the agents, the controllers can accomplish otherwise prohibitive big data processing. Incentive mechanisms are needed for the agents to perform the controllers' tasks in order to satisfy the corresponding objectives of controllers and agents. In this article, a hierarchical game framework with fast convergence and scalability is proposed to meet the demand for real-time processing for such situations. Possible future research directions in this emerging area are also discussed.Item Joint Relay and Jammer Selection for Secure Two-Way Relay Networks(IEEE Transactions on Information Forensics and Security, 8/30/2011) Chen, Jingchao; Zhang, Rongqing; Song, Lingyang; Han, Zhu; Jiao, BingliIn this paper, we investigate joint relay and jammer selection in two-way cooperative networks, consisting of two sources, a number of intermediate nodes, and one eavesdropper, with the constraints of physical-layer security. Specifically, the proposed algorithms select two or three intermediate nodes to enhance security against the malicious eavesdropper. The first selected node operates in the conventional relay mode and assists the sources to deliver their data to the corresponding destinations using an amplify-and-forward protocol. The second and third nodes are used in different communication phases as jammers in order to create intentional interference upon the malicious eavesdropper. First, we find that in a topology where the intermediate nodes are randomly and sparsely distributed, the proposed schemes with cooperative jamming outperform the conventional nonjamming schemes within a certain transmitted power regime. We also find that, in the scenario where the intermediate nodes gather as a close cluster, the jamming schemes may be less effective than their nonjamming counterparts. Therefore, we introduce a hybrid scheme to switch between jamming and nonjamming modes. Simulation results validate our theoretical analysis and show that the hybrid switching scheme further improves the secrecy rate.Item Listen-and-Talk: Protocol Design and Analysis for Full-Duplex Cognitive Radio Networks(IEEE Transactions on Vehicular Technology, 2/29/2016) Liao, Yun; Wang, Tianyu; Song, Lingyang; Han, ZhuIn traditional cognitive radio networks (CRNs), secondary users (SUs) typically access the spectrum of primary users (PUs) by a two-stage “listen-before-talk” (LBT) protocol, i.e., SUs sense the spectrum holes in the first stage before transmitting in the second. However, there exist two major problems: transmission time reduction due to sensing and sensing accuracy impairment due to data transmission. In this paper, we propose a “listen-and-talk” (LAT) protocol with the help of full-duplex (FD) technique that allows SUs to simultaneously sense and access the vacant spectrum. Spectrum utilization performance is carefully analyzed, with the closed-form spectrum waste ratio and collision ratio with the PU provided. In addition, with regard to the secondary throughput, we report the existence of a tradeoff between the secondary transmit power and throughput. Based on the power-throughput tradeoff, we derive the analytical local optimal transmit power for SUs to achieve both high throughput and satisfying sensing accuracy. Numerical results are given to verify the proposed protocol and the theoretical results.Item Non-Cash Auction for Spectrum Trading in Cognitive Radio Networks: Contract Theoretical Model With Joint Adverse Selection and Moral Hazard(IEEE Journal on Selected Areas in Communications, 2/20/2017) Zhang, Yanru; Song, Lingyang; Pan, Miao; Dawy, Zaher; Han, ZhuIn cognitive radio networks (CRNs), spectrum trading is an efficient way for secondary users (SUs) to achieve dynamic spectrum access and to bring economic benefits for the primary users (PUs). Existing methods require full payment from SU, which blocked many potential “buyers,” and thus limited the PU's expected income. To better improve PUs' revenue from spectrum trading in a CRN, we introduce a financing contract, which is similar to a sealed non-cash auction that allows SU to do financing. Unlike previous mechanism designs in CRN, the financing contract allows the SU to only pay part of the total amount when the contract is signed, known as the down payment. Then, after the spectrum is released and utilized, the SU pays the rest of payment, known as the installment payment, from the revenue generated by utilizing the spectrum. The way the financing contract carries out and the sealed non-cash auction works similarly. Thus, contract theory is employed here as the mathematical framework to solve the non-cash auction problem and form mutually beneficial relationships between PUs and SUs. As the PU may not have the full acknowledgment of the SU's transmission status, the problems of adverse selection and moral hazard arise in the two scenarios, respectively. Therefore, a joint adverse selection and moral hazard model is considered here. In particular, we present three situations when either or both adverse selection and moral hazard are present during the trading. Furthermore, both discrete and continuous models are provided in this paper. Through simulations, we show that the adverse selection and moral hazard cases serve as the upper and lower bounds of the general case where both problems are present.Item Overlapping coalition formation games for emerging communication networks(IEEE Network, 9/29/2016) Wang, Tianyu; Song, Lingyang; Han, Zhu; Saad, Walidhomogenous 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.Item Physical Layer Security for Two-Way Untrusted Relaying With Friendly Jammers(IEEE Transactions on Vehicular Technology, 7/23/2012) Zhang, Rongqing; Song, Lingyang; Han, Zhu; Jiao, BingliIn this paper, we consider a two-way relay system where the two sources can only communicate through an untrusted intermediate relay and investigate the physical layer security issue in this two-way untrusted relay scenario. Specifically, we regard the intermediate relay as an eavesdropper from which the information transmitted by the sources needs to be kept confidential, despite the fact that its cooperation in relaying this information is essential. We first indicate that a nonzero secrecy rate is indeed achievable in this two-way untrusted relay system even without the help of external friendly jammers. As for the system with friendly jammers, after further analysis, we can obtain the secrecy rate of the sources can be effectively improved by utilizing proper jamming power from the friendly jammers. Then, we formulate a Stackelberg game between the sources and the friendly jammers as a power control scheme to achieve the optimized secrecy rate of the sources, in which the sources are treated as the sole buyer and the friendly jammers are the sellers. In addition, the optimal solutions of the jamming power and the asking prices are given, and a distributed updating algorithm to obtain the Stackelberg equilibrium is provided for the proposed game. Finally, the simulation results verify the properties and efficiency of the proposed Stackelberg-game-based scheme.Item Radio Resource Allocation for Device-to-Device Underlay Communication Using Hypergraph Theory(IEEE Transactions on Wireless Communications, 3/29/2016) Zhang, Hongliang; Song, Lingyang; Han, ZhuDevice-to-device (D2D) communication has been recognized as a promising technique to offload the traffic for the evolved Node B (eNB). However, D2D transmission as an underlay causes severe interference to both the cellular and other D2D links, which imposes a great technical challenge to radio resource allocation. Conventional graph based resource allocation methods typically consider the interference between two user equipments (UEs), but they cannot model the interference from multiple UEs to completely characterize the interference. In this paper, we study channel allocation using hypergraph theory to coordinate the interference between D2D pairs and cellular UEs, where an arbitrary number of D2D pairs are allowed to share the uplink channels with the cellular UEs. Hypergraph coloring is used to model the cumulative interference from multiple D2D pairs, and thus, eliminate the mutual interference. Simulation results show that the system capacity is significantly improved using the proposed hypergraph method in comparison to the conventional graph based one.Item Real-Time Profiling of Fine-Grained Air Quality Index Distribution Using UAV Sensing(IEEE Internet of Things Journal, 11/27/2017) Yang, Yuzhe; Zheng, Zijie; Bian, Kaigui; Song, Lingyang; Han, ZhuGiven significant air pollution problems, air quality index (AQI) monitoring has recently received increasing attention. In this paper, we design a mobile AQI monitoring system boarded on the unmanned-aerial-vehicles, called ARMS, to efficiently build fine-grained AQI maps in real-time. Specifically, we first propose the Gaussian plume model on the basis of the neural network (GPM-NN), to physically characterize the particle dispersion in the air. Based on GPM-NN, we propose a battery efficient and adaptive monitoring algorithm to monitor AQI at the selected locations and construct an accurate AQI map with the sensed data. The proposed adaptive monitoring algorithm is evaluated in two typical scenarios, a 2-D open space like a roadside park, and a 3-D space like a courtyard inside a building. The experimental results demonstrate that our system can provide higher prediction accuracy of AQI with GPM-NN than other existing models, while greatly reducing the power consumption with the adaptive monitoring algorithm.Item Resource Allocation in Wireless Powered Relay Networks: A Bargaining Game Approach(IEEE Transactions on Vehicular Technology, 12/20/2016) Zheng, Zijie; Song, Lingyang; Niyato, Dusit; Han, ZhuInformation and power transfer in mobile relay networks have recently emerged simultaneously, where the relay can harvest the radio frequency (RF) energy and then use this energy for data forwarding and system operation. Most of the previous works do not consider that the relay may have its own objectives, such as using the harvested energy for its own transmission instead of maximizing transmission of the network. Therefore, in this paper, we propose a Nash bargaining approach to balance the information transmission efficiency of source-destination pairs and the harvested energy of the relay in a wireless powered relay network with multiple source-destination pairs and one relay. We analyze and prove that the Nash bargaining problem has several desirable properties such as the discreteness and quasi-concavity, when it is decomposed into three subproblems: the energy transmission power optimization, the power control for data transmission, and the time division between energy transmission and data transmission. Based on the theoretical analysis, we propose an alternating power control and time-division algorithm to find a suboptimal solution. Simulation results clearly show and demonstrate the properties of the problem and the convergence of our algorithm.Item Social Data Offloading in D2D-Enhanced Cellular Networks by Network Formation Games(IEEE Transactions on Wireless Communications, 7/31/2015) Wang, Tianyu; Sun, Yue; Song, Lingyang; Han, ZhuRecently, cellular networks have become severely overloaded by social-based services, such as YouTube, Facebook, and Twitter, in which thousands of clients subscribe to a common content provider (e.g., a popular singer) and download his/her content updates all the time. Offloading such traffic through complementary networks, such as a delay tolerant network formed by device-to-device (D2D) communications between mobile subscribers, is a promising solution to reduce the cellular burdens. In the existing solutions, mobile users are assumed to be volunteers who selflessly deliver the content to every other user in proximity while moving. However, practical users are selfish and they will evaluate their individual payoffs in the D2D sharing process, which may highly influence the network performance compared to the case of selfless users. In this paper, we take user selfishness into consideration and propose a network formation game to capture the dynamic characteristics of selfish behaviors. In the proposed game, we provide the utility function of each user and specify the conditions under which the subscribers are guaranteed to converge to a stable network. Then, we propose a practical network formation algorithm in which the users can decide their D2D sharing strategies based on their historical records. Simulation results show that user selfishness can highly degrade the efficiency of data offloading, compared with ideal volunteer users. Also, the decrease caused by user selfishness can be highly affected by the cost ratio between the cellular transmission and D2D transmission, the access delays, and mobility patterns.Item Truthful Mechanisms for Secure Communication in Wireless Cooperative System(IEEE Transactions on Wireless Communications, 8/26/2013) Deng, Jun; Zhang, Rongqing; Song, Lingyang; Han, Zhu; Jiao, BingliTo ensure security in data transmission is one of the most important issues for wireless relay networks, and physical layer security is an attractive alternative solution to address this issue. In this paper, we consider a cooperative network, consisting of one source node, one destination node, one eavesdropper node, and a number of relay nodes. Specifically, the source may select several relays to help forward the signal to the corresponding destination to achieve the best security performance. However, the relays may have the incentive not to report their true private channel information in order to get more chances to be selected and gain more payoff from the source. We propose a Vickey-Clark-Grove (VCG) based mechanism and an Arrow-d'Aspremont-Gerard-Varet (AGV) based mechanism into the investigated relay network to solve this cheating problem. In these two different mechanisms, we design different "transfer payment" functions to the payoff of each selected relay and prove that each relay gets its maximum (expected) payoff when it truthfully reveals its private channel information to the source. And then, an optimal secrecy rate of the network can be achieved. After discussing and comparing the VCG and AGV mechanisms, we prove that the AGV mechanism can achieve all of the basic qualifications (incentive compatibility, individual rationality and budget balance) for our system. Moreover, we discuss the optimal quantity of relays that the source node should select. Simulation results verify efficiency and fairness of the VCG and AGV mechanisms, and consolidate these conclusions.Item V2X Meets NOMA: Non-Orthogonal Multiple Access for 5G-Enabled Vehicular Networks(IEEE Wireless Communications, 2017-12) Di, Boya; Song, Lingyang; Li, Yonghui; Han, ZhuBenefiting from widely deployed infrastructure, the LTE network has recently been considered as a promising candidate to support vehicle-to-everything (V2X) services. However, with a massive number of devices accessing the V2X network in the future, the conventional OFDM-based LTE network faces congestion issues due to its low efficiency of orthogonal access, resulting in significant access delay and posing a great challenge especially to safety-critical applications. The non-orthogonal multiple access (NOMA) technique has been well recognized as an effective solution for the future 5G cellular networks to provide broadband communications and massive connectivity. In this article, we investigate the applicability of NOMA in supporting cellular V2X services to achieve low latency and high reliability. Starting with a basic V2X unicast system, a novel NOMAbased scheme is proposed to tackle the technical hurdles in designing high spectrally efficient scheduling and resource allocation schemes in the ultra-dense topology. We then extend it to a more general V2X broadcasting system. Other NOMA-based extended V2X applications and some open issues are also discussed.