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Hua Cai

Bio: Hua Cai is an academic researcher from Seoul National University. The author has contributed to research in topics: Random access & The Internet. The author has an hindex of 1, co-authored 1 publications receiving 24 citations.

Papers
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Proceedings ArticleDOI
19 May 2008
TL;DR: This paper presents the analytically traceable stochastic models to characterize the average delay and throughput performance in wireless mesh networks, and model the forwarding mesh routers as an open queuing network.
Abstract: The wireless mesh network is emerging as a promising technology in providing economical and scalable broadband Internet accesses to communities. The backbone of the wireless mesh network consists of mesh routers, which connect each other in an ad hoc manner via wireless links. The presence of backbone mesh routers and utilization of multiple channels and interfaces allow the wireless mesh network to have better capacity than that of the infrastructure-free ad hoc network formed by mesh clients directly. A special type of the mesh routers, referred to as gateway nodes, is capable of Internet connection, and other mesh routers and associated terminal clients have to access the Internet through the gateway nodes. In this paper, we present the analytically traceable stochastic models to characterize the average delay and throughput performance in wireless mesh networks. We model the forwarding mesh routers as an open queuing network. The analytical model takes into account the mesh router density, the random packet arrival process, the degree of locality of traffic and the collision avoidance mechanism of the IEEE802.11 DCF random access MAC. Our simulation results suggest that the analytical results are quite accurate, which can provide valuable insights in system performance and an effective guideline for the scalable design and optimization in wireless mesh networks.

25 citations


Cited by
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Proceedings ArticleDOI
24 Aug 2015
TL;DR: The results indicated that both IPv4 and IPv6 802.11ac throughput is higher than802.11n, both ac and n IPv6 mode has lower jitter than IPv4's and the delay and drop rate metrics were also measured.
Abstract: With the wireless technologies being widely used, it is for sure that all types of wireless networking will become more and more popular now and in the near future. Therefore, measurement-based performance evaluation of different wireless network standards and traffics is becoming very important. In this research paper, the wireless local area network performance differences between IEEE 802.11n and IEEE 802.11ac technologies of both IPv4 and IPv6 on two Windows 7 operating system computers which been implemented 802.11ac network devices is investigated. The results indicated that both IPv4 and IPv6 802.11ac throughput is higher than 802.11n, both ac and n IPv6 mode has lower jitter than IPv4's. The delay and drop rate metrics were also be measured.

21 citations

Journal ArticleDOI
TL;DR: This paper forms this WDS clustering problem, and proves the NP-completeness of its decision version through reduction from the bin packing problem and presents its two-stage heuristic algorithm where it is verified the effectiveness of the approach through extensive simulations.
Abstract: Wireless mesh networks have been extensively studied as expandable, flexible, and inexpensive access networks to the Internet. This paper focuses on one composed of multiple access points (APs) connected through multihop wireless communications mainly by the wireless distribution system (WDS). For scalability, the proper partition of APs into multiple WDS clusters is essential, because the number of APs in one cluster is limited due to the increasing radio interference and control packets. In this paper, we formulate this WDS clustering problem and prove the NP-completeness of its decision version through reduction from a known NP-complete problem. Then, we propose its heuristic algorithm, using a greedy method and a variable depth search method, to satisfy the complex constraints while optimizing the cost function. We verify the effectiveness of our algorithm through extensive simulations, where the results confirm its superiority to the existing algorithm in terms of throughput.

16 citations

Proceedings ArticleDOI
01 Dec 2015
TL;DR: The major aspects of this project will cover setting up a real time wireless mesh test bed and performance analysis of BATMAN-adv and HWMN and their comparisons.
Abstract: Over the past few years, connections between the end devices or stations have been increasingly wireless. In 1997, 802.11 subcommittee had first approved its Wireless Local Area Network (WLAN) standard. Since then, many wireless networking standards have taken extra efforts in developing mesh architectures in which data is forwarded between multiple wireless hops to reach the desired destination. The main advantage of Wireless Mesh Network over the traditional WLAN is the fact that Wireless Mesh Networks are easy to deploy, flexible, have capability of self-forming, self-healing, and self-organization. In this Project, an implementation and development of wireless mesh network test bed is carried out on the layer 2 routing using Better Approach to Mobile Adhoc Network-advanced (BATMAN-adv) and Hybrid Wireless Mesh Network (HWMN) protocols. The main reason for the use of layer 2 protocol over layer 3 is the less processing overhead that helps in maximizing the throughput. Also, a protocol that runs on layer 2 is capable of supporting any protocol above layer 2. The major aspects of this project will cover setting up a real time wireless mesh test bed and performance analysis of BATMAN-adv and HWMN and their comparisons.

13 citations

Proceedings Article
15 Feb 2009
TL;DR: An effective QoS based provisioning vertical handover decision between IEEE 802.11 and 802.16 is proposed and investigated using QualNet network simulator.
Abstract: Wireless networking is becoming a popular and important way to provide global information access to users on the move. Current technologies are different in their characteristics such as bandwidths, latencies, frequencies and media access methods. Most existing wireless network technologies can be divided into two categories: those that provide a low-bandwidth service over a wide area and those that provide a high bandwidth service over a narrow area. Therefore, we propose an effective QoS based provisioning vertical handover decision between IEEE 802.11 and 802.16. Also, we investigate the proposal using QualNet network simulator.

10 citations

Proceedings ArticleDOI
01 Sep 2011
TL;DR: Experimental results from real-world trials are given, which show that this protocol can maintain a reasonable throughput when nodes are abruptly entering and leaving, making it ideal for a dynamically changing system, such as an ad-hoc network.
Abstract: Fractional cooperation is a decentralized, low-complexity wireless networking protocol in which nodes have the ability to dynamically select a fraction of its resources to commit to forwarding, and where sources may use more than one relay to convey information to the destination. In this paper, an implementation and a series of experiments are presented to demonstrate the practical performance and effectiveness of fractional cooperation. A low-complexity MAC layer protocol is used, which employs fractional cooperation using LT codes in the absence of central coordination. Experimental results from real-world trials are given, which show that this protocol can maintain a reasonable throughput when nodes are abruptly entering and leaving, making it ideal for a dynamically changing system, such as an ad-hoc network. The redundancy of information seen in the network makes this scheme robust to unfavourable channel conditions.

6 citations