• Title/Summary/Keyword: network time-delay

Search Result 1,471, Processing Time 0.03 seconds

A Low Latency Handoff Scheme with Lossless Remote Subscription for Real-time Multimedia Communications in Mobile IP Environments (모바일 IP환경에서의 실시간 멀티미디어 통신을 위한 무손실 원격지 가입 저 지연 핸드오프)

  • Kim Ho-cheal;Kim Young-tak
    • Journal of KIISE:Information Networking
    • /
    • v.31 no.6
    • /
    • pp.620-632
    • /
    • 2004
  • IP is not suitable for mobile nodes by network-based routing because mobile nodes are dynamically change their network attachment point. Mobile-IP is an IETF standard providing continuous access to the Internet for mobile nodes, but it has the triangle routing problem. Also it has a performance degradation problem by massive packet loss during layer 3 handoff of mobile nodes. Especially, two IETF multicast support schemes for Mobile-IP do not guarantee the quality of realtime multimedia services because they have several problems such as long routing path, packet duplication(hi-directional tunneling) and massive packet loss(remote subscription). In this paper, we propose a lossless remote subscription scheme that guarantees the quality of realtime multimedia services over Mobile-IP. From the result of simulation, we verified that the proposed scheme in this paper can reduce the delay time of remote subscription by the effect of the low latency handoff scheme that is extended to apply to the multicast group management and it requires only 0.58% buffer spaces of the previously proposed lossless remote subscription scheme.

Emergency Message Transmission Protocol using CSMA/TDMA in Medical Body Area Networks(MBANs) (Medical Body Area Networks(MBAN)에서 CSMA/TDMA를 이용한 긴급 메시지 전송 프로토콜)

  • Kim, Kyung-Jun
    • Journal of Advanced Navigation Technology
    • /
    • v.13 no.2
    • /
    • pp.224-230
    • /
    • 2009
  • In the latest date, medical body area networks (MBANs) are emerging as a new technology for diagnosis the human body. MBANs in the health care fields are based on short-range and low-power (e.g. ubiquitous computing) among small-sized devices, and have been used by means of medical services. In this paper, we proposed an emergency message transmission protocol using carrier sense multiple access/time division multiple access in MBANs. This scheme focuses on dependability and power-efficiency. In order to increase the reliability of the transmission, this scheme modified a MCTA slot of IEEE 802.15.3 standard to a SR-MCTA slot. SR-MCTA slot is assigned by MBAN coordinator according to requesting terminal nodes. The method, having the priority of transmission, occurs a collision packet randomly. Results from this proposed solution revel that reservation-based TDMA medical body area network(MBAN) protocol for transmitting emergency message was improved in terms of transmission delay.

  • PDF

A Protocol Compression Scheme for Improving Call Processing of Push-To-Talk Service over IMS (IMS망에서 PTT서비스의 통화 처리 성능 향상을 위한 프로토콜 압축 기법)

  • Jung, In-Hwan
    • Journal of Korea Multimedia Society
    • /
    • v.12 no.2
    • /
    • pp.257-271
    • /
    • 2009
  • In this paper, we propose a protocol compression scheme for enhancing the performance of call processing of PTT(Push-to-Talk) which is one of the important services in IMS(IP Multimedia Subsystem), a next generation integrated wired/wireless packet communication network. To service the PTT on an IMS network, it should use the same call setup procedure as legacy Mobile and TRS(Trunked Radio System) networks and have a fast call setup time and enough communication bandwidth because a number of terminals should be able to exchange same data in real time. The proposed A+SigComp scheme reduces the initial call setup delay of SIP by about 10%, which is used by PTT service for call setup. In addition, the A+ROHC scheme is proposed to compress the header of RTP packets transferred during PTT voice transmission and, as a result, about 5% of increase in communication efficiency is observed.

  • PDF

Multicast Methods in Support of Internet Host Mobility (인터넷 상에서 호스트 이동성을 지원하는 멀티캐스트 방안)

  • Bang, Sang-Won;Jo, Gi-Hwan;Kim, Byeong-Gi
    • The Transactions of the Korea Information Processing Society
    • /
    • v.4 no.5
    • /
    • pp.1231-1242
    • /
    • 1997
  • This paper deals with an IP mukticast protocol in support of host mobility. Most of the previous multicast schemes have utilized an underlying logical strucuture of network topology,in order to provide a certain degree of order and predictability.On the other hand,mobility implies that a host location relaative to the rest of the net-work changes with time;the physical connectivity of the entire network is thus modified as move.In this case.some multicast datagrams nay not delivered properly,or may delivered twice or more,to a mobile host because the destinations will keep moving whlist datagrams are dekivered with different time delay.This paper first describes the relation between host mobility and multicast, by exploring the possible interactions,and presents a multicast scheme in support of Internet host mobility.A revised scheme is then proposed to adapt the multicast semantic and to optimize the communication overhead.

  • PDF

Effective IPv6 Address Allocation Mechanism in All IP Wireless Networks (차세대 이동통신망에서 효율전인 IPv6 주소할당 방안)

  • 정현철;민상원
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.29 no.2B
    • /
    • pp.240-249
    • /
    • 2004
  • For the effective IP-based service implementation in the wireless network environment, involvement of IP-related technologies in wireless networks is inevitable and globally unique IPv6 address allocation to the mobile node has become an important issue. In the 3GPP's address allocation mechanism, IPv6 address allocation procedure is performed by the GGSN, which is normally located far from the mobile nodes. This causes IPv6 address allocation time delay and traffics to be longer and increased in the core network, respectively. In this paper, we propose a new IPv6 address allocation mechanism that is performed by Node B located in RAN. The proposed IPv6 address allocation mechanism can provide IPv6 addresses to mobile nodes within a more reduced time than existing 3GPP's IPv6 address allocation mechanism, and co-operates with existing mechanism as an overlay model to improve reliability of wireless networks. And, for implementation of the proposed address allocation mechanism, it needs not to change the structure of current wireless networks except for the some functional addendum of Node B.

A Feedback Control Model for ABR Traffic with Long Delays (긴 지연시간을 갖는 ABR 트래픽에 대한 피드백제어 모델)

  • O, Chang-Yun;Bae, Sang-Hyeon
    • The Transactions of the Korea Information Processing Society
    • /
    • v.7 no.4
    • /
    • pp.1211-1216
    • /
    • 2000
  • Asynchronous transfer mode (ATM) can be efficiently used to transport packet data services. The switching system will support voice and packet data services simultaneously from end to end applications. To guarantee quality of service (QoS) of the offered services, source rateot send packet data is needed to control the network overload condition. Most existing control algorithms are shown to provide the threshold-based feedback control technique. However, real-time voice calls can be dynamically connected and released during data services in the network. If the feedback control information delays, quality of the serviced voice can be degraded due to a time delay between source and destination in the high speed link. An adaptive algorithm based on the optimal least mean square error technique is presented for the predictive feedback control technique. The algorithm attempts to predict a future buffer size from weight (slope) adaptation of unknown functions, which are used fro feedback control. Simulation results are presented, which show the effectiveness of the algorithm.

  • PDF

An ABR Service Traffic Control of Using feedback Control Information and Algorithm (피드백 제어 정보 및 알고리즘을 이용한 ABR 서비스 트래픽제어)

  • 이광옥;최길환;오창윤;배상현
    • Journal of Internet Computing and Services
    • /
    • v.3 no.3
    • /
    • pp.67-74
    • /
    • 2002
  • Asynchronous transfer mode (ATM) can be efficiently used to transport packet data services. The switching system will support voice and packet data services simultaneously from end to end applications. To guarantee quality of service (QoS) of the offered services, source rate to send packet data is needed to control the network overload condition. Most existing control algorithms are shown to provide the threshold-based feedback control technique. However, real-time voice calls can be dynamically connected and released during data services in the network. If the feedback control information delays, quality of the serviced voice can be degraded due to a time delay between source and destination in the high speed link, An adaptive algorithm based on the optimal least mean square error technique is presented for the predictive feedback control technique. The algorithm attempts to predict a future buffer size from weight (slope) adaptation of unknown functions, which are used for feedback control. Simulation results are presented, which show the effectiveness of the algorithm.

  • PDF

Design of a neural network based adaptive noise canceler for broadband noise rejection (광대역 잡음제거를 위한 신경망 적응잡음제거기 설계)

  • 곽우혁;최한고
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.3 no.2
    • /
    • pp.30-36
    • /
    • 2002
  • This paper describes a nonlinear adaptive noise canceler(ANC) using neural networks(NN) based on filter to make up for the drawback of the conventional ANC with the linear adaptive filter. The proposed ANC was tested its noise rejection performance using broadband time-varying noise signal and compared with the ANC of TDL linear filter. Experimental results show that in cases of nonlinear correlations between the noise of primary input and reference input, the neural network based ANC outperforms the linear ANC with respect to mean square error It is also verified that the recurrent NN adaptive filter is superior to the feedforward NN filter. Thus, we identify that the NN adaptive filter is more effective than the linear adaptive filter for rejection of broadband time-varying noise in the ANC.

  • PDF

A Design of MAC Protocol for Dynamic WDM Channel and Bandwidth Allocation in TDM-PON (TDM-PON에서 동적 WDM 채널 및 대역폭 할당을 위한 MAC 프로토콜 설계 연구)

  • Lee Sung-Kuen;Kim Eal-Lae;Lee Yong-Won;Lee Sang-Rok;Jung Dae-Kwang;Hwang Seong-Taek;Oh Yun-Je;Park Jin-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.31 no.9B
    • /
    • pp.777-784
    • /
    • 2006
  • In this paper, we propose the PON-based access network based on conventional TDM-PON architecture, which utilizes WDM wavelength channel and bandwidth dynamically. It is also described a dynamic MAC protocol in order to increase the number of subscribers and efficiency of resource utilization. Of particular importance in the proposed approach for MAC protocol is that the wavelength channel and time slot for up/downlink is dynamically allocated according to the required QoS level and the amount of data in data transmission, through the dedicated control channel between OLT and ONU. We evaluate the performance of average packet end-to-end delay in a statistical analysis and numerical analysis. In addition, through simulations with various traffic models, we verified the superior performance of the proposed approach by comparing with the results of other E-PONs.

QoS Aware Cross-layer MAC Protocol in wireless Sensor Networks (무선 센서 네트워크에서 QoS를 인지하는 Cross-layer MAC 프로토콜)

  • Park, Hyun-Joo;Kim, Seong-Cheol
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.14 no.12
    • /
    • pp.2811-2817
    • /
    • 2010
  • In this paper we propose the QAC-MAC that supports Quality of Service(QoS) and saves energy resources of the sensor node, and hence prolonging the lifetime of the sensor network with multiple sink nodes. Generally, the nodes nearest to the sink node often experience heavy congestion since all data is forwarded toward the sink through those nodes. So this critically effects on the delay-constraint data traffics. QAC-MAC uses a hybrid mechanism that adapts scheduled scheme for medium access and scheduling and unscheduled scheme based on TDMA for no data collision transmission. Generally speaking, characteristics of the real-time traffic with higher priority tends to be bursty and has same destination. QAC-MAC adapts cross-layer concept to rearrange the data transmission order in each sensor node's queue, saves energy consumption by allowing few nodes in data transmission, and prolongs the network lifetime.