• Title/Summary/Keyword: Packet Service Time

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THE MAC LAYER PACKET SERVICE TIME DISTRIBUTIONS OF DCF IN THE IEEE 802.11 PROTOCOL

  • Han Dong-Hwan;Park Chul-Geun
    • Journal of applied mathematics & informatics
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    • v.22 no.1_2
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    • pp.501-515
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    • 2006
  • The IEEE 802.11 protocol is the most mature technology for WLANs(Wireless Local Area Networks). However, as the number of stations increases, the delay and throughput performance of IEEE 802.11 MAC(Medium Access Control) degrades severely. In this paper, we present the comprehensive performance analysis of IEEE 802.11 MAC protocol by investigating the MAC layer packet service time when arrival packet sizes have a general probability distribution. We obtain the discrete probability distribution of the MAC layer service time. By using this, we analyze the system throughput and the MAC layer packet service time of IEEE 802.11 MAC protocol in wireless LAN environment. We take some numerical examples for the system throughput and the mean packet service time for several special distributions of arrival packet sizes.

A Packet Scheduling Algorithm for High-speed Portable Internet System (휴대 인터넷 시스템에서의 패킷 스케줄링 알고리즘 연구)

  • Choi, Seong-Hoon
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.30 no.1
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    • pp.59-65
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    • 2007
  • HPI (High-speed Portable Internet) system which provides high speed internet services is going to be commercialized soon. Since HPI provides simultaneously four different service types such as UGS (Unsolicited Grant Service), rtPS (real time Polling Service), nrtPS(non-real time Polling Service), and BE (Best Effort) under different QoS (Quality of Service) requirements and limited wireless channel resources, efficient packet scheduling mechanisms are necessary to increase the utilization of channels as well as to satisfy the various QoS requirements. This study regards the traffic data to be served as time series and proposes a new packet scheduling algorithm based on the nonparametric statistical test. The performance of the newly proposed algorithm is evaluated through the simulation analysis using a simulator that can evaluate the performance of packet scheduling mechanisms under various values of system parameters and measures such as packet delay time, data transmission rate, number of loss packets, and channel utilization.

An Enhanced Transmission Mechanism for Supporting Quality of Service in Wireless Multimedia Sensor Networks

  • Cho, DongOk;Koh, JinGwang;Lee, SungKeun
    • Journal of Internet Computing and Services
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    • v.18 no.6
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    • pp.65-73
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    • 2017
  • Congestion occurring at wireless sensor networks(WSNs) causes packet delay and packet drop, which directly affects overall QoS(Quality of Service) parameters of network. Network congestion is critical when important data is to be transmitted through network. Thus, it is significantly important to effectively control the congestion. In this paper, new mechanism to guarantee reliable transmission for the important data is proposed by considering the importance of packet, configuring packet priority and utilizing the settings in routing process. Using this mechanism, network condition can be maintained without congestion in a way of making packet routed through various routes. Additionally, congestion control using packet service time, packet inter-arrival time and buffer utilization enables to reduce packet delay and prevent packet drop. Performance for the proposed mechanism was evaluated by simulation. The simulation results indicate that the proposed mechanism results to reduction of packet delay and produces positive influence in terms of packet loss rate and network lifetime. It implies that the proposed mechanism contributes to maintaining the network condition to be efficient.

A Study on QoS Performance Based on CBQ Using Real-time Transport Protocol (RTP를 이용한 CBQ기반의 QoS 성능에 관한 연구)

  • 하미숙;박승섭
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.43-48
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    • 2004
  • RTP that is proposed supplement of real-time services on internet environment, as Real-time Transport Protocol, is the protocol that for the purpose of sending data of stream type. RTP and RTCP(Real-time Transport Control Protocol) basically work at the same time, RTCP serves with state information of network at present. RTP has important properties of a transport protocol that runs on end-to-end systems and provides demultiplexing. It also offer reliability and protocol-defined flow/congestion control that transport protocol like TCP can not provides. In this paper, we look around concept and construction of Differentiated sen1ice tint run on RTP and by setting parameters of packet transfer method be used CBQ(Class-Based Queuing) for packet transfer on Differentiated service, each service queue controls properly through packet scheduling method, such as WRR(Weighted Round Robin) and PRR(Packet-by-packet Round Robin) all service classes do not experience the starvation and confirm the performance through computer simulation to achieve fairly scheduling.

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A Wireless Downlink Packet Scheduling Algorithm for Multimedia Traffic (멀티미디어 트래픽에 대한 무선 환경에서의 순방향 패킷 스케줄링 알고리즘)

  • 김동회;류병한
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.39 no.12
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    • pp.539-546
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    • 2002
  • In this paper, we consider a wireless multimedia environment to service both real-time video traffic and non-real-time WWW-application traffic In our suggested new packet scheduling algorithm, we consider both the accumulation counter and SIR to reduce delay in real-time traffic. In addition, our packet scheduling algorithm gives priority first to real-time video traffic service and then to non-real-time internet Packet service when real-time traffic service is absent. From the simulation results, we find that the AC (Accumulation Counter) scheme has much smaller delay than the conversional M-LWDF scheme for real-time video data users, which has a special quality sensitive to its own delay. We also consider the transmission structure of using both the frame period in the time-axis and the OVSF codes in the code-axis at the same time, which is similar to the structure of HSDPA system.

Performance Analysis of the DQDB Protocol (DQDB (Distributed Queue Dual Bus) 프로토콜의 성능분석)

  • 이창훈;박광만;홍정완
    • Journal of the Korean Operations Research and Management Science Society
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    • v.19 no.3
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    • pp.1-14
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    • 1994
  • In this paper, an analytical model of the message delay in the DQDB (Distributed Queue Dual Bus) network is investigated. The DQDB network has been adopted as a subnetwork for the IEEE 802 MAN (Metropolitan Area Network) standard. The DQDB network consists of two high speed undirectional buses and a series of stations attached to both of the buses. Massages arriving at each station consists of severla packets according to its size. This system is approximated into " $B^{[x]}$/G/1 with exceptional first service queueing " by defining the concept of service time on a packet. The service time for a packet is defined as the time from the instant the packet arrives at the transmission buffer until the time the packet is fully transmitted. By using the BASTA property and the average work in the system, the mean message delay time is obtained.age work in the system, the mean message delay time is obtained.d.

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QoS Packet-Scheduling Scheme for VoIP Services in IEEE 802.16e Systems

  • Jang, Jae-Shin;Lee, Jong-Hyup;Cheong, Seung-Kook;Kim, Young-Sun
    • Journal of Communications and Networks
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    • v.11 no.1
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    • pp.36-41
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    • 2009
  • The IEEE 802.16 wireless metropolitan area network (WMAN) standard is designed to correct expensive communication costs in CDMA-based mobile communication systems and limited coverage problems in wireless LAN systems. Thus, the IEEE 802.16e standard can provide mobile high-speed packet access between mobile stations and the Internet service provider through the base station with cheap communication fees. To efficiently accommodate voice over IP (VoIP) services in IEEE 802.16 systems, an uplink quality of service packet-scheduling scheme is proposed, and its performance is evaluated with an NS-2 network simulator in this paper. Numerical results show that this proposed scheme can increase the system capacity by 100% more than in the unsolicited rand service (UGS) scheme and 30% more than the extended real-time polling service (ertPS) scheme, respectively.

Performance analysis of packet transmission for a Signal Flow Graph based time-varying channel over a Wireless Network (무선 네트워크 time-varying 채널 상에서 Signal Flow Graph를 이용한 패킷 전송 성능 분석)

  • Kim, Sang-Yang;Park, Hong-Seong
    • Proceedings of the KIEE Conference
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    • 2004.05a
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    • pp.65-67
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    • 2004
  • Change of state of Channel between two wireless terminals which is caused by noise and multiple environmental conditions for happens frequently from the Wireles Network. So, When it is like that planning a wireless network protocol or performance analysis, it follows to change of state of time-varying channel and packet the analysis against a transmission efficiency is necessary. In this paper, analyzes transmission time of a packet and a packet in a time-varying and packet based Wireless Network. To reflecte the feature of the time-varying channel, we use a Signal Flow Graph model. From the model the mean of transmission time and the mean of queue length of the packet are analyzed in terms of the packet distribution function, the packet transmission service time, and the PER of the time-varying channel.

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A Study on The Performance Evaluation of Differentiated Service Using Time Sliding Window with 3 Color Marking (3 색 표식을 갖는 타임 슬라이딩 윈도우를 사용하는 차등화 서비스의 성능평가 연구)

  • Chun, Sang-Hun
    • 전자공학회논문지 IE
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    • v.48 no.3
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    • pp.16-19
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    • 2011
  • Differentiated Service is an IP QoS ensuring method based on packet marking that allows packets to be prioritized according to user requirements. During the time of congestion, more low priority packets are dropped than high priority packets. Different policy models are used to determine how to mark the packet. This paper investigated the performance of Differentiated Service using time sliding window with 3 color marking (TSW3CM). Simulation results using NS-2 showed that Differentiated Service can provide the quality of service requirements.

Analysis of Distributed DDQ for QoS Router

  • Kim, Ki-Cheon
    • ETRI Journal
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    • v.28 no.1
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    • pp.31-44
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    • 2006
  • In a packet switching network, congestion is unavoidable and affects the quality of real-time traffic with such problems as delay and packet loss. Packet fair queuing (PFQ) algorithms are well-known solutions for quality-of-service (QoS) guarantee by packet scheduling. Our approach is different from previous algorithms in that it uses hardware time achieved by sampling a counter triggered by a periodic clock signal. This clock signal can be provided to all the modules of a routing system to get synchronization. In this architecture, a variant of the PFQ algorithm, called digitized delay queuing (DDQ), can be distributed on many line interface modules. We derive the delay bounds in a single processor system and in a distributed architecture. The definition of traffic contribution improves the simplicity of the mathematical models. The effect of different time between modules in a distributed architecture is the key idea for understanding the delay behavior of a routing system. The number of bins required for the DDQ algorithm is also derived to make the system configuration clear. The analytical models developed in this paper form the basis of improvement and application to a combined input and output queuing (CIOQ) router architecture for a higher speed QoS network.

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