• Title/Summary/Keyword: Heterogeneous Wireless Networking

Search Result 25, Processing Time 0.027 seconds

Performance Analysis of Operation Strategy of Dual Virtual Cell-based System under The Overlay Convergent Networks of Cognitive Networking (인지 네트워킹 기반 중첩 융합 네트워크에서 이중 가상 셀 운영방안의 성능분석)

  • Choi, Yu-Mi;Kim, Jeong-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.37 no.6B
    • /
    • pp.483-488
    • /
    • 2012
  • With the fast growing data traffic, the performance of the convergent overlay network environment under the cognitive networking environment is crucial for the implementation of the efficient network structure. In order to achieve high capacity and reliable link quality in wireless communication of the overlay convergent networks with the cognitive networking based on the advanced capability of the mobile terminal, a Distributed Wireless Communication System (DWCS) can provide the capability of ambient-aware dual cell system's operation. This paper has considered virtual cell: the Dual Virtual Cell (DVC), and also proposes DVC employment strategy based on DWCS network. One is the Active Virtual Cell which exists for user's actual data traffic and the other is the Candidate Virtual Cell which contains a set of candidate antennas to protect user's link quality from performance degradation or interruption. The considered system constructs DVC by using cognitive ability of finding useful virtual signals. Also, for multi-user high-rate data transmission, the DWCS system exploits Space-Time Trellis Codes. The effects of changing environments on the system performance has been investigated thereafter.

TCP Performance Study in Vertical Handoff across Heterogeneous Wireless Networks (이질적 무선망 사이의 수직적 핸드오프에서의 TCP 성능 분석)

  • Pack Sangheon;Choi Yanghee
    • Journal of KIISE:Information Networking
    • /
    • v.32 no.1
    • /
    • pp.20-28
    • /
    • 2005
  • TCP(Transmission Control Protocol) is one of the most important Internet protocols, which is widely used in wireless networks as well as wired networks. However, when TCP is deployed for wireless networks, it takes severe performance degradation because TCP was designed for wired network. To overcome this drawback, a number of TCP variants have been proposed in the literature. However, most previous schemes did not consider TCP enhancement over heterogeneous networks. In heterogeneous networks, an mobile node (MN) may move from one access network to another(i.e., vertical handover). In the case of vertical handover, an MN experiences a TCP performance degradation caused by the packet loss and the sudden change of link characteristics between two different access networks. In this work, we investigate the TCP performance degradation occurred in vortical handover across heterogeneous networks. First, we have conducted the measurement study over GPRS-WLAN testbed. In the measurement study. we observed the TCP performance degradation in the case of handover from WLAN to GPRS. In order to study more different TCP behaviors during vertical handover, we performed comprehensive simulations using a network simulator 2(ns-2). Based on measurement and simulation results, we investigated how to improve TCP performance in vertical handover and we concluded that the existing mechanisms cannot be perfect solutions and new mechanisms are strongly required.

TCP Throughput Effective Vertical Handoff Decision Scheme for Heterogeneous Wireless Networks (이기종 무선망에서의 TCP 성능 기반 수직적 핸드오프 결정 방안)

  • Seok, Woo-Jin;Choi, Young-Hwan;Kim, Sang-Ha
    • Journal of KIISE:Information Networking
    • /
    • v.34 no.6
    • /
    • pp.505-513
    • /
    • 2007
  • Vertical handoff is a new type of handoff in wireless networks. It is issued when a mobile node moves over overlapping wireless networks with each proving a different access bandwidth, transmission latency, and coverage. By issuing the vertical handoff, the mobile node can obtain better network bandwidth. In the sense of TCP throughput, however, the vertical handoff does not always produce positive performance gain, so sometimes it is better for the mobile node to stay at lower bandwidth providing network rather than to select and move to higher bandwidth providing network. In this paper, we analyze TCP throughput for vertical handoff, and propose a new handoff decision scheme which can estimate TCP throughput at the moment of vertical handoff. Based on the estimation, a mobile node can decide to issue vertical handoff to produce better TCP throughput, and we verify the results by simulations.

3-D Hetero-Integration Technologies for Multifunctional Convergence Systems

  • Lee, Kang-Wook
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.22 no.2
    • /
    • pp.11-19
    • /
    • 2015
  • Since CMOS device scaling has stalled, three-dimensional (3-D) integration allows extending Moore's law to ever high density, higher functionality, higher performance, and more diversed materials and devices to be integrated with lower cost. 3-D integration has many benefits such as increased multi-functionality, increased performance, increased data bandwidth, reduced power, small form factor, reduced packaging volume, because it vertically stacks multiple materials, technologies, and functional components such as processor, memory, sensors, logic, analog, and power ICs into one stacked chip. Anticipated applications start with memory, handheld devices, and high-performance computers and especially extend to multifunctional convengence systems such as cloud networking for internet of things, exascale computing for big data server, electrical vehicle system for future automotive, radioactivity safety system, energy harvesting system and, wireless implantable medical system by flexible heterogeneous integrations involving CMOS, MEMS, sensors and photonic circuits. However, heterogeneous integration of different functional devices has many technical challenges owing to various types of size, thickness, and substrate of different functional devices, because they were fabricated by different technologies. This paper describes new 3-D heterogeneous integration technologies of chip self-assembling stacking and 3-D heterogeneous opto-electronics integration, backside TSV fabrication developed by Tohoku University for multifunctional convergence systems. The paper introduce a high speed sensing, highly parallel processing image sensor system comprising a 3-D stacked image sensor with extremely fast signal sensing and processing speed and a 3-D stacked microprocessor with a self-test and self-repair function for autonomous driving assist fabricated by 3-D heterogeneous integration technologies.

QoS-Guaranteed Realtime Multimedia Service Provisioning on Broadband Convergence Network(BcN) with IEEE 802.11e Wireless LAN and Fast/Gigabit Ethernet

  • Kim, Young-Tak;Jung, Young-Chul;Kim, Seong-Woo
    • Journal of Communications and Networks
    • /
    • v.9 no.4
    • /
    • pp.511-523
    • /
    • 2007
  • In broadband convergence network(BcN), heterogeneous broadband wired & wireless subnetworks and various terminal equipments will be interconnected. In order to provide end-to-end realtime multimedia services on such heterogeneous networking environment, as a result, two major problems should be resolved: i) Multimedia session establishment & negotiation that adjusts the differences in the capability of multimedia data processing at the end terminal nodes, ii) quality of service(QoS)-guaranteed connection establishment or resource reservation with connection admission control(CAC) in each heterogeneous subnetworks along the path. The session layer signaling(e.g., SIP/SDP) should be extended for QoS negotiation, and must be tightly cooperating with network layer signaling or resource reservation with CAC function. In this paper we propose a session and connection management architecture for the QoS-guaranteed realtime multimedia service provisioning on BcN, with Q-SIP/SDP, resource reservation protocol with traffic engineering extension, and CAC functions. The detailed interaction scenario and related algorithms for QoS-guaranteed realtime multimedia session, resource reservation and connection establishment are explained and analyzed. From the experimental implementation of the proposed scheme on a small scale BcN testbed, we verified that the proposed architecture is applicable for the realtime multimedia service provisioning. We analyze the network performance and QoS parameters in detail.

Development of Access Point Supporting Multiple Network Interfaces (다중 네트워크 인터페이스를 지원하는 액세스 포인트 개발에 관한 연구)

  • Lee, Sang-Hak;Chung, Tae-Choong
    • The KIPS Transactions:PartA
    • /
    • v.11A no.3
    • /
    • pp.109-114
    • /
    • 2004
  • Increasing popularity of WLAN and advancement of WPAN allow user to connect to the Internet easily today. The increasing of number of networking mobile device such as laptop and PDA requires computing devices to share high speed Internet line or work on networks in most cases. This has stimulated the demand of access point that supports multiple network interfaces. This paper describes the process of design, implementation and test of the wired/wireless integrated access point that supports multiple network interfaces such as wired LAN, wireless LAN, Bluetooth, and Broadband network. We designed and developed the hardware system and protocol software to integrate heterogeneous network. The system has shown compatibility with standard specification and good performance through testing with various network devices.

Networking Technologies for IPTV2.0 Service (IPTV2.0 서비스를 위한 네트워킹 기술)

  • Lee, Kyounghee;Yoon, Changwoo;Ryu, Won;Kim, Bongtae
    • IEMEK Journal of Embedded Systems and Applications
    • /
    • v.3 no.4
    • /
    • pp.218-228
    • /
    • 2008
  • The convergence of broadcasting and telecommunication services is being accelerated by broadband networks, digital broadcasting and Web2.0. This paper describes the definition and service characteristics of IPTV as a representative of broadcasting and telecommunication convergence services. Especially, the changes of infrastructure and technology for IPTV2.0 are addressed in terms of the service features of mobility, intelligence and participation. IPTV2.0 shall be characterized by the open IPTV service based on Web2.0 and the mobile IPTV service over the heterogeneous networks employing various wireless/wired access technologies. The IP Multimedia Subsystem (IMS) and Service Delivery Platform (SDP) technologies are increasingly considered to support the personalization and openness. The mobility management technology is being evolved to provide QoS-guaranteed mobile communication services to users at anytime and anywhere. IPTV2.0 services and platforms are also anticipated to be core components to achieve knowledge-based ubiquitous society. IPTV2.0 contents are required to be integrated with the enhanced metadata to efficiently support search, selection, convergence and delivery of the contents. Moreover, those contents shall be enhanced to provide the scalable services which is adaptable to the network status and user preferences. Therefore, the networking technologies for IPTV2.0 should tightly cooperate with application services and adaptive contents. Those technologies will be developed to construct the ubiquitous content service platform considering the evolution of networks and various converged services.

  • PDF

Performance Modeling of STTC-based Dual Virtual Cell System under the Overlay Convergent Networks of Cognitive Networking (중첩 융합 네트워크 환경을 고려한 STTC기반 이중 셀 시스템 분석 모델)

  • Choi, YuMi;Kim, Jeong-Ho
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.49 no.12
    • /
    • pp.20-26
    • /
    • 2012
  • The newly introduced model of a STTC-based Distributed Wireless Communication System (DWCS) can provide the capability of joint control of the signals at multiple cells. This paper has considered the virtual cell systems: the Dual Virtual Cell (DVC), and also proposes DVC employment strategy based on DWCS network. The considered system constructs DVC by using antenna selection method. Also, for multi-user high-rate data transmission, the proposed system introduces multiple antenna technology to get a spatial and temporal diversity gain and exploits space-time trellis codes known as STTC to increase a spectral efficiency.

A Java Virtual Machine for Sensor Networks (센서 네트워크를 위한 자바 가상 기계)

  • Kim, Seong-Woo;Lee, Jong-Min;Lee, Jung-Hwa;Shin, Jin-Ho
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.14 no.1
    • /
    • pp.13-20
    • /
    • 2008
  • Sensor network consists of a large number of sensor node distributed in the environment being sensed and controlled. The resource-constrained sensor nodes tend to have various and heterogeneous architecture. Thus, it is important to make its software environment platform-independent and reprogrammable. In this paper, we present BeeVM, a Java operating system designed for sensor networks. BeeVM offers a platform-independent Java programming environment with its efficiently executable file format and a set of class APIs for basic operating functions, sensing and wireless networking. BeeVM's high-level native interface and layered network subsystem allow complex program for sensor network to be short and readable. Our platform has been ported on two currently popular hardware platforms and we show its effectiveness through the evaluation of a simple application.

Can energy optimization lead to economic and environmental waste in LPWAN architectures?

  • Rady, Mina;Georges, Jean-Philippe;Lepage, Francis
    • ETRI Journal
    • /
    • v.43 no.2
    • /
    • pp.173-183
    • /
    • 2021
  • As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance.