• Title/Summary/Keyword: 다중무선통신

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The performance enhancement with multiple antenna algorithm between indoor and outdoor wireless communication (옥내와 옥외간 무선 통신에서 다중 안테나 알고리즘 적용을 통한 통신 성능 향상)

  • Lee Junho;Lee Yong Up;Seo Youngjun;Baang Sungkeun;Kim Jong Dae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.5C
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    • pp.355-363
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    • 2005
  • This paper is discussed about the technology of the performance enhancement in the wireless communication between indoor and outdoor environments. In the outdoor wireless communication, the signal has mainly a severe degradation by the fading effect of channel, but that problem may be overcome by using ordinary multiple antenna technology and array signal processing algorithm. Hence, since the channel has the characteristics of both fading and angle spread in the wireless communication between indoor and outdoor, the ordinary technology cannot solve the signal degradation due to the angle spread. In order to solve the problem, in this paper, the characteristic of the wireless channel between indoor and outdoor is first analyzed and considered the channel models fit to that case. We propose the new multiple antenna algorithm by use of mean steering vector concept, and obtained the results of the performance enhancement. With the results of the performance analyses through of the numerical study and computer simulation, we show that the proposed algorithm has more enhanced signal to noise ratio than the previous algorithm.

Opportunistic Multipath Routing Scheme for Guaranteeing End-to-End Reliability in Large-Scale Wireless Sensor Networks (대규모 무선 센서 망에서 종단 간 신뢰성 보장을 위한 기회적 다중경로 라우팅 방안)

  • Kim, Cheonyong;Jung, Kwansoo;Kim, Sang-Ha
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.10
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    • pp.2026-2034
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    • 2015
  • Wireless sensor networks (WSNs) consist of a lot of sensor nodes having limited transmission range. So multi-hop transmission is used for communication among nodes but the multi-hop transmission degrade the end-to-end reliability. Multipath routing and opportunistic routing are typical approaches for guaranteeing end-to-end reliability in WSNs. The existing protocols improve the reliability effectively in small networks but they suffer from rapid performance degradation in large networks. In this paper, we propose the opportunistic multipath routing protocol for guaranteeing end-to-end reliability in large WSNs. Applying multipath routing and opportunistic routing simultaneously is very hard because their conflicting routing features. The proposed protocol applies these approaches simultaneously by section-based routing thereby enhancing end-to-end reliability. Additionally, the proposed protocol guarantees required reliability by the concept of section reliability. The section reliability over a certain level might satisfy required end-to-end reliability. Our simulation results show that the proposed protocol is more suitable for guaranteeing reliability than existing protocols in large-scale WSNs.

Energy Efficient Selection Scheme for Multiple Wireless Network Interfaces of Mobile Devices (다중 무선 네트워크 휴대 장치를 위한 에너지 효율적인 네트워크 인터페이스 선택 기법)

  • Kim, Bong-Jae;Min, Hong;Gu, Bon-Chul;Jung, Jin-Man;Cho, Yoo-Kun;Heo, Jun-Young;Hong, Ji-Man
    • Journal of KIISE:Computing Practices and Letters
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    • v.16 no.12
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    • pp.1194-1198
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    • 2010
  • Recent mobile devices have multiple wireless network interfaces. Therefore, we can use a more 'energy efficient network interface for reducing energy consumption' according to the network environment without depending on a specific network interface. In this paper, we propose an energy efficient wireless network interface selection scheme for mobile devices with multiple wireless network interfaces. The proposed scheme selects a more energy efficient network interface for data communication by using polling. Also, we show that our scheme is more efficient in terms of energy consumption.

Performance Analysis of Space-Time Transmit Diversity with Adaptive Equalizer in Multipath Channels (다중 경로 채널에서의 적응 등화기를 이용한 시공간 전송 다이버시티 성능 분석)

  • 박현석;곽경섭
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.7A
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    • pp.629-634
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    • 2002
  • The next generation of wireless communication system is expected to provide users with wireless multimedia services such as high speed internet access and wireless mobile computing. Depending on the Quality of Service(QoS) requirements and different applications per user, many wireless communication systems have been proposed. The simple decoding algorithm of space-time block coding is based on the assumption of flat fading channel, where no intersymbol interference exists. In this paper, we propose to combine space-time transmit diversity with adaptive equalizer. The proposed system effectively eliminates interference caused by multipath environment. Simulation results show that the proposed system provides improved bit error rate performance.

Modeling and Analysis of Multi-type Failures in Wireless Body Area Networks with Semi-Markov Model (무선 신체 망에서 세미-마르코프 모델을 이용한 다중 오류에 대한 모델링 및 분석)

  • Wang, Song;Chun, Seung-Man;Park, Jong-Tae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.9B
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    • pp.867-875
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    • 2009
  • The reliability of wireless body area networks is an important research issue since it may jeopardize the vital human life, unless managed properly. In this article, a new modeling and analysis of node misbehaviors in wireless body area networks is presented, in the presence of multi-type failures. First, the nodes are classified into types in accordance with routing capability. Then, the node behavior in the presence of failures such as energy exhaustion and/or malicious attacks has been modeled using a novel Semi-Markov process. The proposed model is very useful in analyzing reliability of WBANs in the presence of multi-type failures.

BER performance of MIMO 16QAM with transmit and receive polarization diversify technique on mobile communication channel (이동통신 채널에서 송수신 편파 디버시티 기법을 채용한 MIMO 16QAM의 BER 성능분석)

  • Kim, Tae-Heon
    • Journal of the Korea Society of Computer and Information
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    • v.13 no.1
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    • pp.135-141
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    • 2008
  • The utilization techniques for multiple transmit and receive antennas or high capacity modulation schemes are essential to cope with the rapidly increasing demand for realizing more diverse wireless communication services with high rates. However, employing multiple receive antennas at the mobile units seems less practical due at the size and power limitations. Therefore, transmit diversify techniques have been extensively investigated for the downlink transmission to improve the performance In order to overcome the above mentioned problems, we construct a simulation model which combines STC and polarization diversity which scheme is requiring less cost to realize. Multi-level quadrature amplitude modulation (MQAM) is an attractive modulation scheme for wireless communication due to the high spectral efficiency it provides. Thus, the performance for our scheme is presented when 16QAM modulation techniques are applied. and compared with the former schemes.

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Delay Analysis under Dynamic Traffic in Network (IEEE 802.11무선망에서 기회적 채널 전환을 통한 다중사용자 다이버시티 이득 향상)

  • Hahm, Seong-Il;Kim, Chong-Kwon
    • Journal of KIISE:Information Networking
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    • v.36 no.3
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    • pp.243-250
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    • 2009
  • Channel diversity is exploited to increase multiuser diversity gains in IEEE 802.11 WLANs. To this end, we propose an opportunistic channel switching method and evaluate this with different number of stations, number of channels, switching latency, and the average channel condition of stations.

Mesh Network Implementation using DWDS-based Link Layer Routing (DWDS 기반의 링크 계층 라우팅을 통한 메쉬 네트워크 구현)

  • Yoon, Mi-Kyung;Yang, Seung-Chur;Kim, Jong-Deok
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.2A
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    • pp.165-173
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    • 2010
  • WMN(Wireless Mesh Network) is an wireless backbone network technology that is an easily configurable network in the low cost compared to the wireless LAN(Local Area Network). Most of the previous researches have evaluated their algorithms by the simulations rather than by the implementation. There exist some implementation papers, however, they have the limitations of the flexibility on the link establishment and the link quality utilization. Consequently, the benefit of the WMN - configuration flexibility is degraded and the performance deterioration occurs in the multi-hop wireless environment. In this paper, we introduce a Linux-based link layer Wireless Mesh Routing System - WBMR. The design and implementation of WBMR provides the dynamic link establishment and the effective multi-channel usage. We have modified the ntroof the original WLAN operation for the dynamic link establishment, and the Linux bridge for the link layer routing. The result of performance evaluation verifies that our WBMR supports fast self-configuration and increases data transmission throughput compared to the other researches of the wireless multi-hop environment.

Target Separation using Wavelet for Multiple Target Localization in Wireless Sensor Network (다중 표적 위치 추정을 위한 무선 센서 네트워크에서 웨이블릿을 이용한 표적 분리)

  • Cha, Dae-Hyun;Lee, Tae-Young;Hong, Jin-Keun;Han, Kun-Hui;Hwang, Chan-Sik
    • Proceedings of the KAIS Fall Conference
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    • 2009.12a
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    • pp.295-298
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    • 2009
  • 다중 표적을 감시하는 무선 센서 네트워크에서 다중 표적이 서로 교차하게 될 때 각각의 표적을 분리하는 문제는 표적의 추적, 탐지, 식별 등의 분야에서 매우 중요하다. 기존의 무선 센서 네트워크에서는 에너지 기반의 기법을 사용하기 때문에 다중 표적의 위치를 추정할 수 없거나, 기지국에서의 원 신호 분석 방법을 통해 표적의 종류를 식별하여 각각의 표적을 분리한다. 후자의 방법은 무선 센서 노드의 통신량과 연산량을 증가시켜 센서 노드의 생존 시간이 짧아지는 단점이 있고, 표적 분리까지 걸리는 시간으로 인해 실시간 처리가 어렵다. 본 논문에서는 무선 센서 노드에서 웨이블릿 변환을 이용한 특징을 추출하고 이를 이용해 다중 표적이 센서 영역 내에서 교차하게 될 때 표적을 분리하는 방법을 제안한다. 제안된 방법은 웨이블릿 상수의 주파수 정보를 이용하여 적은 연산으로 표적을 분리한다.

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