Showing papers on "Testbed published in 2016"

SWaT: a water treatment testbed for research and training on ICS security

Abstract: This paper presents the SWaT testbed, a modern industrial control system (ICS) for security research and training SWaT is currently in use to (a) understand the impact of cyber and physical attacks on a water treatment system, (b) assess the effectiveness of attack detection algorithms, (c) assess the effectiveness of defense mechanisms when the system is under attack, and (d) understand the cascading effects of failures in one ICS on another dependent ICS SWaT consists of a 6-stage water treatment process, each stage is autonomously controlled by a local PLC The local fieldbus communications between sensors, actuators, and PLCs is realized through alternative wired and wireless channels While the experience with the testbed indicates its value in conducting research in an active and realistic environment, it also points to design limitations that make it difficult for system identification and attack detection in some experiments

srsLTE: an open-source platform for LTE evolution and experimentation

Abstract: Testbeds are essential for experimental evaluation as well as for product development. In the context of LTE networks, existing testbed platforms are limited either in functionality and/or extensibility or are too complex to modify and customise. In this work we present srsLTE, an open-source platform for LTE experimentation designed for maximum modularity and code reuse and fully compliant with LTE Release 8. We show the potential of the srsLTE library by extending the baseline code to allow LTE transmissions in the unlicensed bands and coexistence with WiFi. We also expand previous results on this emerging research area by showing how different vendor-specific mechanisms in WiFi cards might affect coexistence.

Optimizing Bulk Transfers with Software-Defined Optical WAN

Abstract: Bulk transfer on the wide-area network (WAN) is a fundamental service to many globally-distributed applications. It is challenging to efficiently utilize expensive WAN bandwidth to achieve short transfer completion time and meet mission-critical deadlines. Advancements in software-defined networking (SDN) and optical hardware make it feasible and beneficial to quickly reconfigure optical devices in the optical layer, which brings a new opportunity for traffic management on the WAN. We present Owan, a novel traffic management system that optimizes wide-area bulk transfers with centralized joint control of the optical and network layers. \sysname can dynamically change the network-layer topology by reconfiguring the optical devices. We develop efficient algorithms to jointly optimize optical circuit setup, routing and rate allocation, and dynamically adapt them to traffic demand changes. We have built a prototype of Owan with commodity optical and electrical hardware. Testbed experiments and large-scale simulations on two ISP topologies and one inter-DC topology show that \sysname completes transfers up to 4.45x faster on average, and up to 1.36x more transfers meet their deadlines, as compared to prior methods that only control the network layer.

Enabling ECN in multi-service multi-queue data centers

Abstract: Recent proposals have leveraged Explicit Congestion Notification (ECN) to achieve high throughput low latency data center network (DCN) transport. However, most of them implicitly assume each switch port has one queue, making the ECN schemes they designed inapplicable to production DCNs where multiple service queues per port are employed to isolate different traffic classes through weighted fair sharing. In this paper, we reveal this problem by leveraging extensive testbed experiments to explore the intrinsic tradeoffs between throughput, latency, and weighted fair sharing in multi-queue scenarios. Using the guideline learned from the exploration, we design MQ-ECN, a simple yet effective solution to enable ECN for multi-service multiqueue production DCNs. Through a series of testbed experiments and large-scale simulations, we show that MQ-ECN breaks the tradeoffs by delivering both high throughput and low latency simultaneously, while still preserving weighted fair sharing.

System design of the internet of things for residential smart grid

Abstract: The Internet of Things envisions integration, coordination, communication, and collaboration of real-world objects in order to perform daily tasks in a more intelligent and efficient manner. To comprehend this vision, this article studies the design of a large-scale IoT system for smart grid application, which constitutes a large number of home users and has the requirement of fast response time. In particular, we focus on the messaging protocol of a universal IoT home gateway, where our cloud enabled system consists of a back-end server, a unified home gateway (UHG) at the end users, and a user interface for mobile devices. We discuss the features of such an IoT system to support a large-scale deployment with a UHG and real-time residential smart grid applications. Based on the requirements, we design an IoT system using XMPP and implemented in a testbed for energy management applications. To show the effectiveness of the designed testbed, we present some results using the proposed IoT architecture.

City of things: An integrated and multi-technology testbed for IoT smart city experiments

Abstract: While smart cities have the potential to monitor and control the city in real-time through sensors and actuators, there is still an important road ahead to evolve from isolated smart city experiments to real large-scale deployments. Important research questions remain on how and which wireless technologies should be setup for connecting the city, how the data should be analysed and how the acceptance by users of applications can be assessed. In this paper we present the City of Things testbed, which is a smart city testbed located in the city of Antwerp, Belgium to address these questions. It allows the setup and validation of new smart city experiments both at a technology and user level. City of Things consists of a multi-wireless technology network infrastructure, the capacity to easily perform data experiments on top and a living lab approach to validate the experiments. In comparison to other smart city testbeds, City of Things consists of an integrated approach, allowing experimentation on three different layers: networks, data and living lab while supporting a wide range of wireless technologies. We give an overview of the City of Things architecture, explain how researchers can perform smart city experiments and illustrate this by a case study on air quality.

ExoGENI: A Multi-Domain Infrastructure-as-a-Service Testbed.

Abstract: NSF’s GENI program seeks to enable experiments that run within virtual network topologies built-to-order from testbed infrastructure offered by multiple providers (domains). GENI is often viewed as a network testbed integration effort, but behind it is an ambitious vision for multi-domain infrastructure-as-a-service (IaaS). This paper presents ExoGENI, a new GENI testbed that links GENI to two advances in virtual infrastructure services outside of GENI: open cloud computing (OpenStack) and dynamic circuit fabrics. ExoGENI orchestrates a federation of independent cloud sites and circuit providers through their native IaaS interfaces, and links them to other GENI tools and resources.

System Design of Internet-of-Things for Residential Smart Grid

Abstract: Internet-of-Things (IoTs) envisions to integrate, coordinate, communicate, and collaborate real-world objects in order to perform daily tasks in a more intelligent and efficient manner. To comprehend this vision, this paper studies the design of a large scale IoT system for smart grid application, which constitutes a large number of home users and has the requirement of fast response time. In particular, we focus on the messaging protocol of a universal IoT home gateway, where our cloud enabled system consists of a backend server, unified home gateway (UHG) at the end users, and user interface for mobile devices. We discuss the features of such IoT system to support a large scale deployment with a UHG and real-time residential smart grid applications. Based on the requirements, we design an IoT system using the XMPP protocol, and implemented in a testbed for energy management applications. To show the effectiveness of the designed testbed, we present some results using the proposed IoT architecture.

A Highly Integrated and Reconfigurable Microgrid Testbed with Hybrid Distributed Energy Sources

Abstract: A highly integrated and reconfigurable microgrid testbed is presented in this paper. The microgrid testbed contains various distributed generation units and diverse energy storage systems. Apart from electrical power, it can also provide energy in forms of hydrogen and thermal energy. The topology of this testbed is very flexible with different combinations of buses and feeders. The deployment of hybrid distributed energy sources and the highly reconfigurable structure are available to meet different research requirements. Extensive experiments have been carried out to provide verification for microgrid research and guides for microgrid projects. Some experimental results are shown in this paper in several aspects of microgrid research, including performance evaluation of distributed energy sources, verification of control schemes in ac/dc hybrid microgrid, investigation of fault transients, and feasibility of protection schemes.

Practical MU-MIMO user selection on 802.11ac commodity networks

Abstract: Multi-User MIMO, the hallmark of IEEE 802.11ac and the upcoming 802.11ax, promises significant throughput gains by supporting multiple concurrent data streams to a group of users. However, identifying the best-throughput MU-MIMO groups in commodity 802.11ac networks poses three major challenges: a) Commodity 802.11ac users do not provide full CSI feedback, which has been widely used for MU-MIMO grouping. b) Heterogeneous channel bandwidth users limit grouping opportunities. c) Limited-resource on APs cannot support computationally and memory expensive operations, required by existing algorithms. Hence, state-of-the-art designs are either not portable in 802.11ac APs, or perform poorly, as shown by our testbed experiments. In this paper, we design and implement MUSE, a lightweight user grouping algorithm, which addresses the above challenges. Our experiments with commodity 802.11ac testbeds show MUSE can achieve high throughput gains over existing designs.

Cyber-Physical System Security of a Power Grid: State-of-the-Art

Abstract: As part of the smart grid development, more and more technologies are developed and deployed on the power grid to enhance the system reliability. A primary purpose of the smart grid is to significantly increase the capability of computer-based remote control and automation. As a result, the level of connectivity has become much higher, and cyber security also becomes a potential threat to the cyber-physical systems (CPSs). In this paper, a survey of the state-of-the-art is conducted on the cyber security of the power grid concerning issues of: (1) the structure of CPSs in a smart grid; (2) cyber vulnerability assessment; (3) cyber protection systems; and (4) testbeds of a CPS. At Washington State University (WSU), the Smart City Testbed (SCT) has been developed to provide a platform to test, analyze and validate defense mechanisms against potential cyber intrusions. A test case is provided in this paper to demonstrate how a testbed helps the study of cyber security and the anomaly detection system (ADS) for substations.

An In-depth Study of Mobile Browser Performance

Abstract: Mobile page load times are an order of magnitude slower compared to non-mobile pages. It is not clear what causes the poor performance: the slower network, the slower computational speeds, or other reasons. Further, most Web optimizations are designed for non-mobile browsers and do not translate well to the mobile browser. Towards understanding mobile Web page load times, in this paper we: (1) perform an in-depth pairwise comparison of loading a page on a mobile versus a non-mobile browser, and (2) characterize the bottlenecks in the mobile browser {\em vis-a-vis} non-mobile browsers. To this end, we build a testbed that allows us to directly compare the low-level page load activities and bottlenecks when loading a page on a mobile versus a non-mobile browser. We find that computation is the main bottleneck when loading a page on mobile browsers. This is in contrast to non-mobile browsers where networking is the main bottleneck. We also find that the composition of the critical path during page load is different when loading pages on the mobile versus the non-mobile browser. A key takeaway of our work is that we need to fundamentally rethink optimizations for mobile browsers.

A Survey on Energy-Aware Design and Operation of Core Networks

Abstract: A detailed survey of approaches reducing energy consumption of core networks is presented in this paper. We consider a multilayer architecture, in which the optical layer can be realized either with a Wavelength Division Multiplexing (WDM) network or an Elastic Optical Network (EON). We focus on the design and operation stages, i.e., deciding which devices to install in the network during the former step, and choosing which devices to put into sleep mode during the latter one. A taxonomy for classifying the surveyed approaches is provided in order to compare the works covering energy efficiency in core networks (in terms of both optimal formulations and heuristic solutions). Moreover, our work provides a global view of the traffic assumptions, the topologies, and the power consumption models in the literature. The need of further investigations in this field clearly emerges. We envision future works targeting: (1) more effective standardization efforts to practically realize sleep modes; (2) the evaluation of the impact of sleep mode on the device lifetime; (3) the extensive adoption of new paradigms like Software Defined Networking (SDN) and EON; and (4) a radical improvement in the testbed implementations.

An Internet of Things Framework for Smart Energy in Buildings: Designs, Prototype, and Experiments

Abstract: Smart energy in buildings is an important research area of Internet of Things (IoT). Buildings as important parts of the smart grids, their energy efficiency is vital for the environment and global sustainability. Using a LEED-gold-certificated green office building, we built a unique IoT experimental testbed for our energy efficiency and building intelligence research. We first monitor and collect one-year-long building energy usage data and then systematically evaluate and analyze them. The results show that due to the centralized and static building controls, the actual running of green buildings may not be energy efficient even though they may be "green" by design. Inspired by "energy proportional computing" in modern computers, we propose a IoT framework with smart location-based automated and networked energy control, which uses smartphone platform and cloud computing technologies to enable multi-scale energy proportionality including building-, user-, and organizational-level energy proportionality. We further build a proof-of-concept IoT network and control system prototype and carried out real-world experiments which demonstrate the effectiveness of the proposed solution. We envision that the broad application of the proposed solution has not only led to significant economic benefits in term of energy saving, improving home/office network intelligence, but also bought in a huge social implication in terms of global sustainability.

Testbed for subjective evaluation of omnidirectional visual content

Abstract: Omni-directional visual content is a form of representing graphical and cinematic media content which provides subjects with the ability to freely change their direction of view. Along with virtual reality, omnidirectional imaging is becoming a very important type of the modern media content. This brings new challenges to the omnidirectional visual content processing, especially in the field of compression and quality evaluation. More specifically, the ability to assess quality of omnidirectional images in reliable manner is a crucial step to provide a rich quality of immersive experience. In this paper we introduce a testbed suitable for subjective evaluations of omnidirectional visual contents. We also show the results of a conducted pilot experiment to illustrate the applicability of the proposed testbed.

SUDOI: software defined networking for ubiquitous data center optical interconnection

Abstract: Ubiquitous data center optical interconnection is a promising scenario to meet the high burstiness and high-bandwidth requirements of services in terms of the user-access-oriented interconnection between user and data center, inter-data- center, and intra-data-center interconnection. However, in the current mode of operation, the control of the data center and optical network is separately deployed. Enabling even limited interworking among these separated control systems does not provide a mechanism to exchange resource information and enhance the high-level performance requirement of applications. Our previous work implemented cross-stratum optimization of optical network and application strata resources inter-data-center, which allows the accommodation of data center services. In view of this, this study extends to the ubiquitous data center optical interconnection scenario. This article presents a novel SUDOI architecture aimed at extensive user access from the perspective of heterogeneous cross-stratum and multi-layer networking modes. SUDOI can enable cross-stratum optimization of application and optical network stratum resources, and enhance multiple- layer resource integration in the ubiquitous data center optical interconnection. The functional modules of SUDOI architecture, including the core elements of various controllers, are described in detail. The cooperation procedure in user-access-oriented interconnection, multiple- layer resource integration inter-data-center, and intra-data-center service modes is investigated. The feasibility and efficiency of the proposed architecture are also experimentally demonstrated on our OaaS testbed with OpenFlow-enabled optical nodes, and compared to the CSO scheme in terms of blocking probability and resource occupation rate. Numerical results are given and analyzed based on the testbed. Some future discussion and exploration issues are presented in the conclusion.

Synchronization Protocols and Implementation Issues in Wireless Sensor Networks: A Review

Abstract: Time synchronization in wireless sensor networks (WSNs) is a topic that has been attracting the research community in the last decade. Most performance evaluations of the proposed solutions have been limited to theoretical analysis and simulation. They consequently ignored several practical aspects, e.g., packet handling jitters, clock drifting, packet loss, and mote limitations, which affect real implementation on sensor motes. Authors of some pragmatic solutions followed empirical approaches for the evaluation, where the proposed solutions have been implemented on real motes and evaluated in testbed experiments. This paper gives an insight on issues related to the implementation of synchronization protocols in WSN. The challenges related to WSN environment are presented; the importance of real implementation and testbed evaluation are motivated by some experiments we conducted. The most relevant implementations of the literature are then reviewed, discussed, and qualitatively compared. While there are several survey papers that present and compare the protocols from the conception perspectives, as well as others that deal with mathematical and signal processing issues of the estimators, a survey on practical aspects related to the implementation is missing. To our knowledge, this paper is the first one that takes into account the practical aspect of existing solutions.

The Balance Attack Against Proof-Of-Work Blockchains: The R3 Testbed as an Example

Abstract: In this paper, we identify a new form of attack, called the Balance attack, against proof-of-work blockchain systems. The novelty of this attack consists of delaying network communications between multiple subgroups of nodes with balanced mining power. Our theoretical analysis captures the precise tradeoff between the network delay and the mining power of the attacker needed to double spend in Ethereum with high probability. We quantify our probabilistic analysis with statistics taken from the R3 consortium, and show that a single machine needs 20 minutes to attack the consortium. Finally, we run an Ethereum private chain in a distributed system with similar settings as R3 to demonstrate the feasibility of the approach, and discuss the application of the Balance attack to Bitcoin. Our results clearly confirm that main proof-of-work blockchain protocols can be badly suited for consortium blockchains.

Traffic-Aware Cloud RAN: A Key for Green 5G Networks

Abstract: Next generation 5G wireless networks envision innovative radio technologies for ultra dense deployment with improved coverage and higher data rates. However, the deployment of ultra dense 5G networks, with relatively smaller cells, raises significant challenges in network energy consumption. Emerging green cloud radio access networks (C-RANs) are providing assurance of energy efficient cellular operations for reduction of both greenhouse emissions and operators’ energy bill. Cellular traffic dynamics play a significant role in efficient network energy management. In this paper, we first identify the complexity of the optimal traffic awareness in 5G C-RAN and design a framework for traffic-aware energy optimization. The virtual base station cluster (VBSC) of C-RAN exploits an information theoretic approach to model and analyze the uncertainty of cellular traffic, captured by remote radio heads (RRH). Subsequently, using an online, stochastic game theoretic algorithm, the VBS instances optimize and learn the cellular traffic patterns. Efficient learning makes the C-RAN aware of the near-future traffic. Traffic awareness helps in selective switching of a subset of RRHs, thus reducing the overall energy consumption. Our VBS prototype implementation, testbed experiments, and simulation results, performed with actual cellular traffic traces, demonstrate that our framework results in almost 25% daily energy savings and 35% increased energy efficiency with a negligible overhead.

Dynamic module deployment in a fog computing platform

Abstract: Several applications, such as smart cities, smart homes and smart hospitals adopt Internet of Things (IoT) networks to collect data from IoT devices. The incredible growing speed of the number of IoT devices congests the networks and the large amount of data, which are streamed to data centers for further analysis, overload the data centers. In this paper, we implement a fog computing platform that leverages end devices, edge networks, and data centers to serve the IoT applications. In this paper, we focus on implementing a fog computing platform, which dynamically pushes programs to the devices. The programs pushed to the devices pre-process the data before transmitting them over the Internet, which reduces the network traffic and the load of data centers. We survey the existing platforms and virtualization technologies, and leverage them to implement the fog computing platform. Moreover, we formulate a deployment problem of the programs. We propose an efficient heuristic deployment algorithm to solve the problem. We also implement an optimal algorithm for comparisons. We conduct experiments with a real testbed to evaluate our algorithms and fog computing platform. The proposed algorithm shows near-optimal performance, which only deviates from optimal algorithm by at most 2% in terms of satisfied requests. Moreover, the proposed algorithm runs in real-time, and is scalable. More precisely, it computes 1000 requests with 500 devices in < 2 seconds. Last, the implemented fog computing platform results in real-time deployment speed: it deploys 20 requests < 10 seconds.

Experimental Study on Key Generation for Physical Layer Security in Wireless Communications

Abstract: This paper presents a thorough experimental study on key generation principles, i.e., temporal variation, channel reciprocity, and spatial decorrelation, through a testbed constructed by using wireless open-access research platform. It is the first comprehensive study through: 1) carrying out a number of experiments in different multipath environments, including an anechoic chamber, a reverberation chamber, and an indoor office environment, which represents little, rich, and moderate multipath, respectively; 2) considering static, object moving, and mobile scenarios in these environments, which represents different levels of channel dynamicity; and 3) studying two most popular channel parameters, i.e., channel state information and received signal strength. Through results collected from over a hundred tests, this paper offers insights to the design of a secure and efficient key generation system. We show that multipath is essential and beneficial to key generation as it increases the channel randomness. We also find that the movement of users/objects can help introduce temporal variation/randomness and help users reach an agreement on the keys. This paper complements existing research by experiments constructed by a new hardware platform.

A survey on the security of cyber-physical systems

Abstract: Cyber-physical systems (CPSs) are integrations of computation, communication, control and physical processes. Typical examples where CPSs are deployed include smart grids, civil infrastructure, medical devices and manufacturing. Security is one of the most important issues that should be investigated in CPSs and hence has received much attention in recent years. This paper surveys recent results in this area and mainly focusses on three important categories: attack detection, attack design and secure estimation and control. We also discuss several future research directions including risk assessment, modeling of attacks and attacks design, counter-attack strategy and testbed and validation.

A Mobile Multi-Technology Gateway to Enable IoT Interoperability

Abstract: In the Internet of Things (IoT) vision, all our everyday objects will be equipped with processing, sensing and actuating capabilities and need to be connected to the Internet to provide their full potential benefits. Our life will be surrounded by an ecosystem of smart "things" that need to be found, accessed, managed and interconnected to other things. For that purpose, we introduce an IoT Gateway solution based on a smartphone becoming a universal interface between the Internet and the Things. We propose a high-level, unified and extendible smartphone software architecture for "thing" discovery/management and for data collection, processing and forwarding to Internet and Cloud. We evaluated the feasibility of the proposed solution, throughout the implementation of a specific testbed. System performances are evaluated in terms of energy consumption, CPU and memory usage. Obtained results validated the soundness of the proposed approach presenting a low usage of hardware resources even if, the consumption introduced by the radio interfaces and the reduced capacity of current batteries, significantly limit the smartphone lifetime. This latter aspect will certainly be exceeded in a short time since the technological progress daily produces more efficient radio interfaces and batteries.

Model-based security analysis of a water treatment system

Abstract: An approach to analyzing the security of a cyber-physical system (CPS) is proposed, where the behavior of a physical plant and its controller are captured in approximate models, and their interaction is rigorously checked to discover potential attacks that involve a varying number of compromised sensors and actuators. As a preliminary study, this approach has been applied to a fully functional water treatment testbed constructed at the Singapore University of Technology and Design. The analysis revealed previously unknown attacks that were confirmed to pose serious threats to the safety of the testbed, and suggests a number of research challenges and opportunities for applying a similar type of formal analysis to cyber-physical security.

Experimental demonstration of multi-dimensional resources integration for service provisioning in cloud radio over fiber network

Abstract: Cloud radio access network (C-RAN) becomes a promising scenario to accommodate high-performance services with ubiquitous user coverage and real-time cloud computing in 5G area. However, the radio network, optical network and processing unit cloud have been decoupled from each other, so that their resources are controlled independently. Traditional architecture cannot implement the resource optimization and scheduling for the high-level service guarantee due to the communication obstacle among them with the growing number of mobile internet users. In this paper, we report a study on multi-dimensional resources integration (MDRI) for service provisioning in cloud radio over fiber network (C-RoFN). A resources integrated provisioning (RIP) scheme using an auxiliary graph is introduced based on the proposed architecture. The MDRI can enhance the responsiveness to dynamic end-to-end user demands and globally optimize radio frequency, optical network and processing resources effectively to maximize radio coverage. The feasibility of the proposed architecture is experimentally verified on OpenFlow-based enhanced SDN testbed. The performance of RIP scheme under heavy traffic load scenario is also quantitatively evaluated to demonstrate the efficiency of the proposal based on MDRI architecture in terms of resource utilization, path blocking probability, network cost and path provisioning latency, compared with other provisioning schemes.

C-RoFN: multi-stratum resources optimization for cloud-based radio over optical fiber networks

Abstract: C-RAN has become a promising scenario to accommodate high-performance services, which provides ubiquitous user coverage and supports real-time cloud computing using cloud BBUs. The interaction between RRH and BBU or resource schedule among BBUs in cloud have become more frequent and complex due to the development of system-scale and user requirements. The heavy-duty interaction can promote the networking demand among RRHs and BBUs, and forces to form elastic optical fiber switching and optical networking according to the characteristics of high bandwidth, low cost, and transparent multi-rate traffic transmission. In such a network, the multiple stratum resources of radio, optical, and BBU processing unit have interwoven with each other, so the traditional architecture cannot efficiently implement the resource optimization and scheduling for the high-level QoS guarantee. In this article, we present a novel C-RoFN architecture for MSRO using software defined networking. The proposed architecture can globally optimize radio frequency, optical spectrum, and BBU processing resources effectively to maximize radio coverage and meet the QoS requirement. The functional modules of C-RoFN architecture, including the core elements of radio, optical, and BBU controllers, are described in detail. The cooperation procedures in multi-layer vertical integration and cross-stratum horizontal merging models are investigated. The overall feasibility and efficiency of the proposed architecture are also experimentally demonstrated on our SDN-enabled testbed with OpenFlow-enabled elastic optical nodes, and compared to cross-stratum optimization strategy in terms of resource occupation and path provisioning latency. Numerical results are given and analyzed based on the testbed. Some future discussions are presented in the conclusion.

Enhancement for content delivery with proximity communications in caching enabled wireless networks: architecture and challenges

Abstract: To cater for the exploding growth of video traffic, small cell base stations (SBSs) and deviceto- device-enabled caching and delivery have been regarded as promising techniques for future wireless networks. In this article, we design a proximity communications enhanced multilayer caching and delivery architecture. Then merits possessed by the proposed architecture are highlighted, and challenges and open issues are comprehensively presented. Specifically, we shed light on the trade-offs between key performance indicators (e.g., hit ratio, latency, and coverage) and operation costs (e.g., device storage space, wireless bandwidth, and device battery life), and then clarify fundamental coupling between content caching and delivery. To further verify the effectiveness of the cooperation among SBSs and user equipments, we propose a distributed content caching and delivery strategy, jointly considering popularity distribution, diverse storage capability, and user mobility. Simulation results demonstrate that the proposed strategy can significantly lower the content retrieval latency and reduce the traffic flowing to core networks. Furthermore, design details of the experimental testbed are presented, and the validity of our developed strategy is verified.