• Title/Summary/Keyword: Wireless QoS

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A Dynamic Frequency Allocation for Provisioning QoS in Cognitive Radio System (무선 인지 기반 시스템에서 QoS 보장 동적 주파수 할당)

  • Lee, Mun-Ho;Lee, Jong-Chan
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 2008.10b
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    • pp.634-642
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    • 2008
  • Radio wave is the valuable resources in $21^{st}$ century. It will be widely used in various applications such as DMB, USN, telematics, and home network as well as mobile and wireless communications. Cognitive Radio technology is devised to maximize the utilization of radio resources by sensing near-by spectrum and dynamic and allocating free resources dynamically and adaptively. Wireless links for the secondary user need to be frequently switched to idle frequencies during the transmission of multimedia data in the cognitive radio based system. This may cause delay and information loss, and QoS degradations occur inevitably. The efficient frequency allocation scheme is necessary to support the seamless multimedia service to the secondary user while maintaining QoS of the primary user. This paper suggests a frequency selection scheme which considers other parameters such as cell load, data rate, and available bandwidth than just received signal strength during the frequency selection process. The performance of our proposed scheme is analyzed by simulation.

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Proportional Fair Scheduling Algorithm in OFDMA-Based Wireless Systems with QoS Constraints

  • Girici, Tolga;Zhu, Chenxi;Agre, Jonathan R.;Ephremides, Anthony
    • Journal of Communications and Networks
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    • v.12 no.1
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    • pp.30-42
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    • 2010
  • In this work we consider the problem of downlink resource allocation for proportional fairness of long term received rates of data users and quality of service for real time sessions in an OFDMA-based wireless system. The base station allocates available power and subchannels to individual users based on long term average received rates, quality of service (QoS) based rate constraints and channel conditions. We formulate and solve a joint bandwidth and power optimization problem, solving which provides a performance improvement with respect to existing resource allocation algorithms. We propose schemes for flat as well as frequency selective fading cases. Numerical evaluation results show that the proposed method provides better QoS to voice and video sessions while providing more and fair rates to data users in comparison with existing schemes.

Performance Analysis of the IEEE 802.16 Broadband Wireless Access systems

  • Cho Dong-hoon;Kim Hyun-Sook;Kim Jin-nyun;Ha Nam-koo;Han Ki-jun
    • Proceedings of the IEEK Conference
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    • summer
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    • pp.176-180
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    • 2004
  • In this paper we introduce a bandwidth allocation algorithm and admission control policy for IEEE 802.16 broadband wireless access standard. The proposed mechanism is practical and compatible to the IEEE 802.16. Our scheme provides QoS support to high priority traffic and high throughput in low priority traffic. The simulation show that the proposed scheme includes QoS support for real-time traffic and we presented that BS determine a efficient contention mini-slot size. We have shown the relationship between traffic size and its QoS requirements and the network performance.

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A Study on the QoS Performance of the Mobile WiMAX (Mobile WiMAX의 QoS 성능에 관한 연구)

  • Park, Sang-Hoon;Kim, Joeng-Hoon;Kwon, Soon-Ryang;Lee, Dong-Myung
    • Proceedings of the IEEK Conference
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    • 2007.07a
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    • pp.17-18
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    • 2007
  • Mobile WiMAX technology is the key solution for providing high speed internet services at anytime and anywhere in mobile environments as 3.5th wireless technology between 3rd generation and 4th generation wireless technology, and the service demands shall be rapidly increased in future some years. This paper analyzed the QoS performance of Mobile WiMAX technology recommended by IEEE 802.16e specification under the restricted simulation conditions and environments. The major metrics for analyzing QoS performance of Mobile WiMAX are 1) total packet drop rates; 2) transmission / receive packet sizes; 3) end to end delay in node 2; 4) packet drop rate by mobile terminal mobility.

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A New Multicast MAC Protocol for Wireless Ad Hoc Network (무선 Ad Hoc 네트워크의 새로운 멀티캐스트 매체접근제어 프로토콜)

  • Lim Jae-Hwan;Bang Kee-Chun
    • Journal of Digital Contents Society
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    • v.4 no.2
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    • pp.203-210
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    • 2003
  • In this paper we proposed a new MAC protocol to improve QoS(Quality of Service) for real-time traffic in wireless Ad Hoc networks. NMAC protocol have a contention period reservation scheme and a priority control scheme to provide fairness of nodes and QoS. Through simulation, the NMAC protocol compared with existing CSMA MAC protocols shows improvement in performance.

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Energy Efficient Routing Scheme for Wireless Sensor Networks (무선 센서네트워크에서 효율적인 라우팅 기법에 대한 연구)

  • Kim, Dong-Sik;Kim, Sung-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.5A
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    • pp.417-422
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    • 2010
  • In this paper, we propose a new routing scheme based on the multiple layer routing strategy. This algorithm can guarantee the required QoS while maximizing energy efficiency in wireless sensor networks. The principle contributions of this work are its simplicity, scalability and responsiveness to current network situations. Simulation results indicate the superior performance of our proposed algorithm, while other existing scheme cannot offer such an attractive performance balance.

Approximation Method for QoS Analysis of Wireless Cellular Networks with Impatient Calls

  • Eom, Hee-Yeol;Kim, Che-Soong;Melikov, Agassi;Fattakhova, Mehriban
    • Industrial Engineering and Management Systems
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    • v.9 no.4
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    • pp.339-347
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    • 2010
  • Simple-closed expressions for approximate calculation of quality of service (QoS) metrics of isolated cell of wireless networks with either finite or infinite queues of both new and handover calls are developed. It is assumed that both kinds of calls might leave the system without receiving service if their waiting times exceed some threshold value. For the models with infinite queues of heterogeneous calls easily checkable ergodicity conditions are proposed. The high accuracy of the developed approximation formulas is shown. Results of numerical experiments are given.

Multi-layer Surveillance System based on Wireless Mesh Networks (무선 메쉬 네트워크 기반의 다층구조 감시 시스템 구축)

  • Yoon, Tae-Ho;Song, Yoo-Seoung
    • IEMEK Journal of Embedded Systems and Applications
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    • v.7 no.5
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    • pp.209-217
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    • 2012
  • In the present, Wireless Sensor Network(WSN) has been used for the purpose of the military operation with surveillance systems and for collecting useful information from the natural environment. Basically, low-power, easy deployment and low cost are the most important factors to be deployed for WSNs. Lots of researches have been studied to meet those requirements, especially on the node capacity and battery lifetime improvements. Recently, the study of wireless mesh networks applied into the surveillance systems has been proceeded as a solution of easy deployment. In this paper, we proposed large-scale intelligent multi-layer surveillance systems based on QoS assuring Wireless Mesh Networks and implemented them in the real testbed environment. The proposed system explains functions and operations for each subsystem as well as S/W and H/W architectures. Experimental results are shown for the implemented subsystems and the performance is satisfactory for the surveillance system. We can identify the possibility of the implemented multi-layer surveillance system to be used in practice.

An Adjustable Round Robin Scheduling Algorithm for the High Data Rate Mobile Communication System (고속 이동 통신을 위한 적응 가능한 라운드 로빈 스케줄링 방식)

  • Bae, Jeong-Min;Song, Young-Keum;Kim, Dong-Woo
    • Journal of KIISE:Information Networking
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    • v.34 no.1
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    • pp.27-32
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    • 2007
  • Next-generation wireless networks are expected to support a wide range of services, including high-rate data applications, Various service types request differentiated QoSs(Qualities of Service) such as minimum data rate, accuracy, fairness and so on. Although resources of radio systems are limited, for many applications, it is important that certain QoS targets are required to be met. In this paper, we propose a QoS based scheduling algorithm for next generation systems, based on analyzing previous researches, and we develop the proposed QoS algorithm only for MIMO(multi-Input Multi-Output) systems. Moreover, we subsequently prove that the proposed algorithm optimize throughput relative to prespecified target values and converge to certain throughput.

QoS in IEEE 802.11 Wireless Networks using Back-off Parameter Selecting (Back-off 파라미터 설정을 통한 IEEE 802.11 무선 네트워크에서의 QoS 보장)

  • Mun Jeong-A;Lee Sang-kyu
    • Proceedings of the Korean Information Science Society Conference
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    • 2005.11a
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    • pp.412-414
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    • 2005
  • 무선 랜 표준인 IEEE 802.11은 원래 best effort service를 위해 탄생된 기술이기 때문에 QoS(Quality of Service)에 대한 연구가 부족했다. 무선 랜에서는 기존 유선 랜보다 한정된 자원과 희박한 bandwidth, 다양한 노드들의 채널 공유로 인해 QoS를 보장하기가 어렵다. 이를 보완하기 위한 연구가 IEEE 802.11e 워킹그룹에서 진행되고 있다. 본 논문에서는 충돌방지를 위한 CSMA/CA 알고리즘의 back-off값 설정을 매개변수를 두어 idle 시간을 조정함으로써 QoS를 보장하는 알고리즘을 제안한다. 특히, QoS가 요구하는 패킷전달 간격 임계값(threshold)에 따른 매개변수를 조절하여 contention window 크기를 달리 조정함으로써 QoS를 요구하는 노드들의 수에 상관없이 균일한 서비스 성능을 유지하도록 한다. 이 때, 매개변수 값의 선택은 QoS를 제공하는 노드들의 서비스 성능 뿐 아니라 best effort service만을 제공해도 되는 일반 노드들의 서비스 성능도 함께 고려할 수 있도록 하였다.

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