• Title/Summary/Keyword: MAC(Multiple Access Control)

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S-ARQ: A New Truncated ARQ for IP-Based Wireless Network

  • Choi, Young-Kyu;Oh, Seong-Jun;Choi, Sung-Hyun
    • Journal of Communications and Networks
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    • v.12 no.2
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    • pp.174-180
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    • 2010
  • Automatic Repeat reQuest (ARQ) is a very effective technique against transmission error at the medium access control (MAC) layer. An erroneous MAC protocol data unit can be typically retransmitted within a given limit. In order to improve the IP-level performance, which directly affects the user-perceived quality-of-service (QoS), we propose a new truncated ARQ strategy, called MAC service data unit-based ARQ (S-ARQ), where the finite number of opportunities for retransmissions are shared by multiple fragments out of an IP datagram. We describe how SARQ can be implemented in a practical system, and then propose another variant of S-ARQ employing a functionality called early detection of failure. Basically, we evaluate the performance of SARQ in two different manners. First, assuming i.i.d. error process, we analyze both the probability of the delivery failure and the average delay of IP datagram. Then, we assess the performance of S-ARQ via simulation over a 2-state Markov channel.

Block Ack-based Dynamic A-MPDU Aggregation Scheme in IEEE 802.11n WLAN (IEEE 802.11n WLAN에서 블록 승인 기반의 동적 A-MPDU 집적 방법)

  • Shin, In Cheol;Kim, Dong-Hoi
    • Journal of Broadcast Engineering
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    • v.19 no.4
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    • pp.510-520
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    • 2014
  • By adopting the MAC(Media Access Control) protocol which enables to pack multiple MPDUs(MAC-level Protocol Data Units) into a single PPDU(Physical Layer Protocol Data Unit), IEEE 802.11n WLAN supports high throughput. Up to now, there have been a lot of existing channel information-based A-MPDU schemes dynamically determining the number of MSDUs according to the wireless channel condition information which is sent from the receiver to sender. However, the channel information-based scheme has a serious drawback having a high system overhead due to the frequent channel feedback information. To reduce the system overhead, the proposed BA-base dynamic A-MPDU scheme simply chooses the number of MSDUs to be retransmitted by not the frequent channel feedback information but the BA signal representing whether MPSUs belonging to the A-MPDU are received or not. Through NS-2(Network Simulator-2), we found that the proposed scheme had higher throughput and lower packet error rate than the existing fixed A-MPDU scheme.

Performance Analysis of a BRAM (The Broadcast Recognizing Aceess Method) Protocol in a Wireless LAN (무선 근거리 통신망에서의 BRAM(The Broadcast Recognizing Access Method) 프로토콜 성능 분석)

  • 김재현;이종규
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.1
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    • pp.1-8
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    • 1994
  • In this paper, we have analyzed the performance of a BRAM (The Broadcasting Recognizing Access Method) protocol, as a CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) scheme, which is widely used in wireles LAN systems. We have selected a Fair BRAM protocol among CSMA/CA schemes, considering the fairness of channel usage and the simplicity of the protocol. We have compared the performance of BRAM protocol to that of CSMA/CD. to research the characteristics of BRAM in wireless LAN system. In order to analyze the performance of this system, we have set up an imbedded Markov chain and calculated state transition probabilities. Then we have calculated steady state probabilities and finally derived the throughput of a Fair BRAM moder. To verify our analysis, we have simulated practical models. Then, we have found that analytic results are very close to simulation ones. Our analysis of the BRAM protocol will be expected to be very helpful to design and evaluate a MAC (Media Access Control) protocol in wireless LAN systems.

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Real-Time Transmission Scheme for Ad Hoc Self-Organizing (ASO) TDMA in Multi-Hop Maritime Communication Network (Ad Hoc Self-Organizing (ASO) TDMA 방식 다중-홉 해양통신망에서의 실시간 전송 기법)

  • Cho, Kumin;Yun, Changho;Lim, Yong-Kon;Kang, Chung G.
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39B no.5
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    • pp.260-270
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    • 2014
  • In this paper, we first analyze the delay performance of Dynamic Space-time Subframe (DSTS)-based frame structure which has been proposed to support the real-time service as well as non real-time service, using Ad hoc Self-Organizing Time Division Multiple Access (ASO-TDMA) MAC protocol, especially when transmitting a MAC SDU with two or more MAC PDUs, in a multi-hop ad-hoc maritime communication network. We propose two key transmission schemes: contiguous DSTS reservation which guarantees the end-to-end delay for the multiple PDUs, and adaptive transmission probability control schemes to maximize the system throughput. Our simulation results show that the proposed schemes outperform the system throughput of the existing transmission schemes, while supporting the real-time requirement.

A Performance Analysis of CSMA in Wireless Networks Based on MIL-STD-188-220 (MIL-STD-188-220기반 무선네트워크의 CSMA 성능분석)

  • Seo, NanSol;Joo, JaeWoo;Jang, DohngWoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37C no.11
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    • pp.1129-1137
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    • 2012
  • The wireless link of tactical datalink system provides a communication network to share digitalized tactical data in real-time. Also MAC(Multiple Access Control) of this system is subject to TDMA or CSMA according to a operated circumstance of target nodes to exchange the data reliably. In this paper, we verify the operability when we use CSMA scheme based on MIL-STD-188-220 in tactical datalink system which is basically designed with TDMA, and provide a mathematical analysis scheme to verify the operability and performance. Finally, by implementing CSMA scheme to a tactical datalink equipment we obtain practical results which can be compared with theoretical results.

A CSMA/CA with Binary Exponential Back-off based Priority MAC Protocol in Tactical Wireless Networks (전술 무선망에서 2진 지수 백오프를 사용하는 CSMA/CA 기반 우선순위 적용 MAC 프로토콜 설계)

  • Byun, Ae-Ran;Son, Woong;Jang, Youn-Seon
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.11
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    • pp.12-19
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    • 2015
  • In network-centric warfare, the communication network has played a significant role in defeating an enemy. Especially, the urgent and important data should be preferentially delivered in time. Thus, we proposed a priority MAC protocol based on CSMA/CA with Binary Exponential Back-off for tactical wireless networks. This MAC protocol suggested a PCW(Prioritized Contention Window) with differentiated back-off time by priority and a RBR(Repetitive Back-off Reset) to reset the remaining back-off time. The results showed that this proposed MAC has higher performance than those of DCF(Distributed Coordination Function) in the transmission success rate and the number of control packet transmission by reducing the packet collision. Thus, it produced more effective power consumption. In comparison with DCF, this proposed protocol is more suitable in high-traffic network.

Development of DVS167 OOB Processor in POD Module for OpenCable (OpenCable 용 POD 모듈의 DVS167 OOB Processor 개발)

  • 박부식;위정욱;임기택
    • Proceedings of the IEEK Conference
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    • 2003.07b
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    • pp.843-846
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    • 2003
  • In this paper, we have analyzed algorithm of physical layer, data link layer and MAC layer of Out-Of-Band (OOB) specified in the OpenCabl $e^{TM}$SCTE-55-2 2002$^{[3]}$ and designed architecture of the OOB processor. The OOB processor performs fundamental multiple access control for the OOB channel and extracts session key information from a EMM packet for descrambling MPEG-2 streams. In this paper, we have implemented a prototype board for the DVS167 OOB processor and verified it.t.

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Performance Analysis of the Ranging Protocol for the ATM-PON based on ITU-T G.983.1 (G.983.1 기반의 ATM-PON에서 Ranging 프로토콜 성능 분석)

  • Hwang, Kye-Won;Chung, Hae;Kim, Jin-Hee;Koh, Sang-Ho;Yoo, Gun-Il
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.6A
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    • pp.1078-1088
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    • 2001
  • ATM-PON (Asynchronous Transfer Mode Passive Optical Network)에는 두 가지 핵심 기술이 있는데 ranging 프로토콜과 MAC (Medium Access Control) 프로토콜이 그것이다. Ranging 프로토콜은 시간 분할 다중화(Time Division Multiple Access, TDMA) 방식을 사용하는 ATM-PON에서 상향으로 액세스할 때 타임 슬롯의 동기를 유지하게 하기 위해 ONU (Optical Network Unit)를 가상적으로 동일한 거리에 놓는 기술이다. 본 논문에서는 FSAN (Full Service Access Network)과 ITU-T를 중심으로 표준화된 G.983.1의 ranging 프로토콜에 관하여 연구하고 성능분석과 모의실험을 수행한다. 이를 통하여 ranging을 하는데 걸리는 소요시간이 표준안의 권고사항을 만족시키기 위한 필요조건을 도출할 수 있다. 특히 ranging을 할 때 윈도우의 길이를 줄일 수 있는 새로운 방식을 적용하여, 이미 서비스 중에 있는 ONU의 서비스 품질이 저하되는 것을 막을 수 있음을 보여준다.

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A Metro WDM Star Network with a Hybrid MAC Protocol Based on an Arrayed Waveguide Grating

  • Kirmani, Syed Abdul Mannan;Shin, Seo-Yong;Yang, Hyo-Sik
    • Journal of the Optical Society of Korea
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    • v.11 no.2
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    • pp.59-62
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    • 2007
  • In this paper, we introduce a reliable, scalable, and cost-effective switchless wavelength division multiplexing (WDM) network based on a quality-of-service supporting reservation-based medium access control (MAC) protocol. The protocol not only provides both packet and circuit switching but also supports multicasting. The network efficiency is significantly increased by spatially reusing wavelengths and exploiting multiple free spectral ranges (FSRs) of arrayed waveguide grating (AWG) employed in the architecture. We have demonstrated the feasibility of this architecture by simulating in $Optsim^{TM}$.

Performance Analysis of Directional CSMA/CA for IEEE 802.15.3c under Saturation Environments

  • Kim, Mee-Joung;Kim, Yong-Sang;Lee, Woo-Yong
    • ETRI Journal
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    • v.34 no.1
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    • pp.24-34
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    • 2012
  • In this paper, the directional carrier sense multiple access/collision avoidance (CSMA/CA) protocol in the immediate acknowledgement mode for IEEE 802.15.3c is analyzed under saturation environments. For the analysis, a sensing region and an exclusive region with a directional antenna are computed probabilistically and a Markov chain model in which the features of IEEE 802.15.3c and the effects of using directional antennas are incorporated is analyzed. An algorithm to find the maximal number of concurrently transmittable frames is proposed. The system throughput and the average transmission delay are obtained in closed forms. The numerical results show the impact of directional antennas on the CSMA/CA media access control (MAC) protocol. For instance, the throughput with a small beamwidth of antenna is more than ten times larger than that for an omnidirectional antenna. The overall analysis is verified by a simulation. The obtained results will be helpful in developing an MAC protocol for enhancing the performance of mmWave wireless personal area networks.