scispace - formally typeset
Search or ask a question
Author

Xuxun Liu

Bio: Xuxun Liu is an academic researcher from South China University of Technology. The author has contributed to research in topics: Wireless sensor network & Key distribution in wireless sensor networks. The author has an hindex of 20, co-authored 35 publications receiving 1731 citations.

Papers
More filters
Journal ArticleDOI
09 Aug 2012-Sensors
TL;DR: A comprehensive and fine grained survey on clustering routing protocols proposed in the literature for WSNs, and a novel taxonomy of WSN clustering routed methods based on complete and detailed clustering attributes are presented.
Abstract: The past few years have witnessed increased interest in the potential use of wireless sensor networks (WSNs) in a wide range of applications and it has become a hot research area. Based on network structure, routing protocols in WSNs can be divided into two categories: flat routing and hierarchical or clustering routing. Owing to a variety of advantages, clustering is becoming an active branch of routing technology in WSNs. In this paper, we present a comprehensive and fine grained survey on clustering routing protocols proposed in the literature for WSNs. We outline the advantages and objectives of clustering for WSNs, and develop a novel taxonomy of WSN clustering routing methods based on complete and detailed clustering attributes. In particular, we systematically analyze a few prominent WSN clustering routing protocols and compare these different approaches according to our taxonomy and several significant metrics. Finally, we summarize and conclude the paper with some future directions.

635 citations

Journal ArticleDOI
TL;DR: This paper offers a classification of atypical hierarchical routing of WSNs, and gives detailed analysis of different logical topologies, to provide useful guidance for system designers on how to evaluate and select appropriate logical topological protocols for specific applications.
Abstract: Hierarchical routing in wireless sensor networks (WSNs) is a very important topic that has been attracting the research community in the last decade. Typical hierarchical routing is called clustering routing, in which the network is divided into multiple clusters. Recently, some types of atypical hierarchical routing arise, including chain-based, tree-based, grid-based routing, and area-based routing. There are several survey papers that present and compare the hierarchical routing protocols from various perspectives, but a survey on atypical hierarchical routing is still missing. This paper makes a first attempt to provide a comprehensive review on atypical hierarchical routing. We offer a classification of atypical hierarchical routing of WSNs, and give detailed analysis of different logical topologies. The most representative atypical hierarchical routing protocols are described, discussed, and qualitatively compared. In particular, the advantages and disadvantages of different atypical hierarchical routing protocols are analyzed with respect to their significant performances and application scenarios. Finally, we put forward some open issues concerning the design of hierarchical WSNs. This survey aims to provide useful guidance for system designers on how to evaluate and select appropriate logical topologies and hierarchical routing protocols for specific applications.

180 citations

Journal ArticleDOI
TL;DR: This paper considers the problem of grid-based coverage with low-cost and connectivity-guarantee (GCLC) with a novel deployment approach, ACO-Greedy, based on the ant colony optimization with greedy migration mechanism, which can quickly complete the full coverage, and markedly decrease the deployment cost.

120 citations

Journal ArticleDOI
TL;DR: A novel low-cost code dissemination model is proposed which disseminate the update code by using the mobile vehicles in the city with an opportunistic communication style and a coverage based greedy deployment scheme for code stations and an optimized code selection algorithm are proposed to maximize coverage of code dissemination over the citywith low cost and duration time.

107 citations

Journal ArticleDOI
TL;DR: The objective is to minimize the energy consumption of the entire MEC system, by considering the delay constraint as well as the uncertain resource requirements of heterogeneous computation tasks, using a mixed-integer nonlinear programming (MINLP) problem and a value iteration-based reinforcement learning (RL) method.
Abstract: Mobile Edge Computing (MEC) has emerged as a promising computing paradigm in the 5G architecture, which can empower User Equipments (UEs) with computation and energy resources offered by migrating workloads from UEs to the nearby MEC servers. Although the issues of computation offloading and resource allocation in MEC have been studied with different optimization objectives, they mainly focus on facilitating the performance in the quasi-static system, and seldomly consider time-varying system conditions in the time domain. In this paper, we investigate the joint optimization of computation offloading and resource allocation in a dynamic multi-user MEC system. Our objective is to minimize the energy consumption of the entire MEC system, by considering the delay constraint as well as the uncertain resource requirements of heterogeneous computation tasks. We formulate the problem as a Mixed Integer Non-Linear Programming (MINLP) problem, and propose a value iteration based Reinforcement Learning (RL) method, named Q-Learning, to determine the joint policy of computation offloading and resource allocation. To avoid the curse of dimensionality, we further propose a Double Deep Q Network (DDQN) based method, which can efficiently approximate the value function of Q-learning. Simulation results demonstrate that the proposed methods significantly outperform other baseline methods in different scenarios, except the Exhaustion method. Especially, the proposed DDQN based method achieves very close performance with the Exhaustion method, and can significantly reduce the average of 20%, 35%, 53% energy consumption compared with Offloading Decision, Local First method, and Offloading First method, respectively when the number of UEs is 5.

96 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: The family of NL maximization techniques is introduced, the portrayal of rich variety definitions of NL design objective used for WSNs, and some design guidelines with examples are provided to show the potential improvements of the different design criteria.
Abstract: Emerging technologies, such as the Internet of Things, smart applications, smart grids, and machine-to-machine networks stimulate the deployment of autonomous, self-configuring, large-scale wireless sensor networks (WSNs). Efficient energy utilization is crucially important in order to maintain a fully operational network for the longest period of time possible. Therefore, network lifetime (NL) maximization techniques have attracted a lot of research attention owing to their importance in terms of extending the flawless operation of battery-constrained WSNs. In this paper, we review the recent developments in WSNs, including their applications, design constraints, and lifetime estimation models. Commencing with the portrayal of rich variety definitions of NL design objective used for WSNs, the family of NL maximization techniques is introduced and some design guidelines with examples are provided to show the potential improvements of the different design criteria.

502 citations

Journal ArticleDOI
TL;DR: This survey presents various ML-based algorithms for WSNs with their advantages, drawbacks, and parameters effecting the network lifetime, covering the period from 2014–March 2018.

434 citations

Journal ArticleDOI
TL;DR: A state-of-the-art and comprehensive survey on clustering approaches in WSNs, which surveys the proposed approaches in the past few years in a classified manner and compares them based on different metrics such as mobility, cluster count, cluster size, and algorithm complexity.

433 citations

Journal ArticleDOI
TL;DR: The Blockchain technologies which can potentially address the critical challenges arising from the IoT and hence suit the IoT applications are identified with potential adaptations and enhancements elaborated on the Blockchain consensus protocols and data structures.

355 citations

Journal ArticleDOI
TL;DR: A survey on clustering over the last two decades reveals that QoS aware clustering demands more attention and indicates that clustering techniques enhanced with smart network selection solutions could highly benefit the QoS and QoE in IoT.
Abstract: Wireless sensor network (WSN) systems are typically composed of thousands of sensors that are powered by limited energy resources. To extend the networks longevity, clustering techniques have been introduced to enhance energy efficiency. This paper presents a survey on clustering over the last two decades. Existing protocols are analyzed from a quality of service (QoS) perspective including three common objectives, those of energy efficiency, reliable communication and latency awareness. This review reveals that QoS aware clustering demands more attention. Furthermore, there is a need to clarify how to improve quality of user experience (QoE) through clustering. Understanding the users’ requirements is critical in intelligent systems for the purpose of enabling the ability of supporting diverse scenarios. User awareness or user oriented design is one remaining challenging problem in clustering. In additional, this paper discusses the potential challenges of implementing clustering schemes to Internet of Things (IoT) systems in 5G networks. We indicate that clustering techniques enhanced with smart network selection solutions could highly benefit the QoS and QoE in IoT. As the current studies for WSNs are conducted either in homogeneous or low level heterogeneous networks, they are not ideal or even not able to function in highly dynamic IoT systems with a large range of user scenarios. Moreover, when 5G is finally realized, the problem will become more complex than that in traditional simplified WSNs. Several challenges related to applying clustering techniques to IoT in 5G environment are presented and discussed.

248 citations