• Title/Summary/Keyword: CSMA

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Collision alleviation algorithm with Binomial Backoff retransmission method in CSMA/CA of Wireless VHF Communication (무선 VHF통신의 CSMA/CA에서 Binomial Backoff 재전송 방식을 이용한 충돌 완화 알고리즘)

  • 박용태;김용중;이동준;박효달
    • Proceedings of the IEEK Conference
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    • 2003.11c
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    • pp.235-238
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    • 2003
  • 본 논문에선 Binomial확률을 이용한 재전송 슬롯 선택방식과 충돌해결과정의 수정을 통하여 CSMA/CA 프로토콜을 항공용 VHF통신에 적합하게 변형시켰다. 일반적으로 CSMA/CA 프로세스는 경쟁 서비스에서 충돌이 일어났을 때 재전송 지연시간만큼 기다리게 되고 경쟁윈도우의 크기가 두 배로 커진다. 이로 인해 부하가 증가하면 지연시간이 커지고 처리량이 감소하며 이를 해결하기 위해 본 논문에선 충돌 플래그를 이용하여 본래의 CW의 크기 변화 과정을 변형시켰으며, CSMA/CA 전체 상태 천이 과정에서 충돌 시의 과정을 좀더 적게 거치도록 하였다. 시뮬레이션을 수행한 결과 부하가 증가하여도 처리량 및 지연 시간에 좋은 특성을 나타내었으며 제안된 프로토콜은 항공용 VHF 통신에 적합함을 확인하였다.

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Simulation of Slotted CSMA/CA MAC in IEEE 802.15.4 WPAN (IEEE 802.15.4 무선 PAN의 Slotted CSMA/CA MAC 시뮬레이션)

  • Lee Hae Rim;Chung Min Young;Lee Tae-Jin
    • Journal of the Korea Society for Simulation
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    • v.14 no.3
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    • pp.101-108
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    • 2005
  • IEEE 802.15.4 low-rate Wireless Personal Area Networks (WPAN) are expected to provide ubiquitous networking between small personal/home devices and sensors with low power consumption and low cost features. The technology employs special CSMA/CA (Carrier Sense Multiple Access/collision Avoidance) to save power consumption for small or portable WPAN-enabled devices. In this paper, we simulation the slotted CSMA/CA of IEEE 802.15.4 MAC and evaluate its performance limit in order to grasp the characteristics of Medium Access Control (MAC) of IEEE 802.15.4 WPAN.

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Simulation of Slotted CSMA/CA MAC in IEEE 802.15.4 WPAN (IEEE 802.15.4 무선 PAN의 Slotted CSMA/CA MAC 시뮬레이션)

  • Lee Hae Rim;Chung Min Young;Lee Tae-Jin
    • Proceedings of the Korea Society for Simulation Conference
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    • 2005.05a
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    • pp.10-14
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    • 2005
  • IEEE 802.15.4 low-rate Wireless Personal Area Networks(WPAN) are expected to provide ubiquitous networking between small personal/home devices and sensors with low power consumption and low cost features. The technology employs special CSMA/CA (Carrier Sense Multiple Access/collision Avoidance) to save power consumption for small or portable WPAN-enabled devices. In this paper, we simulation the slotted CSMA/CA of IEEE 802.15.4 MAC and evaluate its performance limit in order to grasp the characteristics of Medium Access Control (MAC) of IEEE 802.15.4 WPAN.

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An Adaptive Back-off Algorithm in Beacon-Enabled LR-WPAN (비콘 기반 저속 WPAN에서의 적응적 백오프 알고리즘)

  • Park, Sung-Woo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.11 no.8
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    • pp.735-742
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    • 2016
  • The Low-Rate WPAN is a short range wireless networking technology characterized by low-rate, low-power, low complexity and low-cost. The LR-WPAN controls wireless channel access among network devices based on the contention-based CSMA/CA algorithm. Therefore, frame collisions may take place at any time, leading to the severe degradation of network performance. This paper proposes a new algorithm that changes back-off periods adaptively in the CSMA/CA process depending on network conditions, resulting in the reduction of frame collisions. Throughout extensive simulations, it turns out that varying the back-off periods dynamically shows better performance than maintaining the fixed back-off periods.

A study on the MAC protocol for an aeronautical mobile data communication (항공용 이동 무선 데이터 통신에 적합한 매체접속제어 프로토콜에 관한 연구)

  • 이은주;박효달
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.11
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    • pp.2604-2612
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    • 1997
  • Media access control(MAC) protocol that is used between aircraft and ground station now is non-persistent CSMA protocol, but this protocol hs defects to apply in the wireless mobile radio communication environment. In this paper, to solve this Problems, the modified ICMA/CD protocol which ban be applied in the wireless environment was proposed and analyzed. In the modified ICMA/CD protocol, instead of usig special control channel, control signal was inserted into the uplink message. After the analysis, simulation was performed to approve the analysis resutls. As a results, modified ICMA/CD protocol can solve the hidden termined effect of CSMA protocol and packet detection delay time problem of ICMA/CD protocol and acquired the same channel throughput as CSMA/CD protocol. This results shows the modified ICMA/CD protocol can be used in the aeronauical telecommunication.

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Modeling and Evaluation of Wireless Communication System using CSMA inthe Distributed Packet Radio Network (분산 무선망에서 CSMA를 사용한 무선 통신 시스템의 모델링 및 성능 분석)

  • 조병록;최형진;박병철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.10
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    • pp.1508-1517
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    • 1993
  • In this paper, we propose the modeling of a wireless communication system using CSMA protocol, present analytical evalution and simulation as a function of arrival rate and mean END-to-END delay in the distributed packet radio network. Asynchronous 1-persistent CSMA protocol is used in wireless communication system with half duplex. We assume that all terminals are to be in the close range of each other, suitably located in the local area. The traffic presented to a common channel is assumed to be poisson distribution. Analytical model is based on a M/D/1 with breakdown. In conclusion for wireless network model proposed in this paper is suitable for packet arrival rate of 2 packet/sec with mean packet delay time less than 2 times the packet transmission time.

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A Variable Priority MAC Protocol for QoS Guarantee in Wireless ad hoc Networks (무선 ad hoc 망에서 QoS 보장을 위한 가변 우선순위 MAC 프로토콜)

  • Park, Ha-Young;Kim, Chang-Wook;Han, Jung-Ahn;Kim, Byoung-Gi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.7B
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    • pp.463-471
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    • 2007
  • Because of MANET's dynamic characteristic, the hidden node problem can happen. Thus it must use with distributed channel access. In Ad hoc networks, carrier sense multiple access with collision avoidance(CSMA/CA) is one of the most widely used medium access control(MAC) schemes for asynchronous data traffics. However, CSMA/CA could not guarantee the quality of multimedia traffics. CSMA is a contention based protocol. Therefor once a node gets a channel, it can momopolze. Thus the fairness problem with channel starvation will happen. We will propose a new MAC protocol to guarantee QoS for multimedia data in ad hoc networks.

A Study on Performance Improvement of High- Rate WPAN using Hybrid MAC (고속 WPAN에서 Hybrid MAC을 이용한 성능 향상)

  • Park, Sung-Hyun;Rhee, Seung-Hyong
    • Journal of Internet Computing and Services
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    • v.10 no.4
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    • pp.213-222
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    • 2009
  • IEEE 802.15.3 HR-WPAN is designed to enable wireless connectivity of high-speed, low-power, low-cost multimedia-capable portable consumer electronic devices. For quality of service, the standard specifies the use of TDMA (Time Division Multiple Access). However, during low contention TDMA gives much lower channel utilization and higher delays than CSMA (Carrier Sensing Multiple Access) because in TDMA, a node can transmit only during its scheduled time slots whereas in CSMA, nodes can transmit at any time as long as there is no contention. By mixing CSMA and TDMA, Hybrid MAC becomes more robust to timing failures, time-varying channel conditions, slot assignment failures and topology changes than a stand-alone TDMA.

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A Priority-based Time Slot Allocation Protocol for Hybrid MAC in WSNs (WSN에서 하이브리드 MAC을 위한 우선순위기반 타임 슬롯 할당 프로토콜)

  • Nam, Jae-Hyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.6
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    • pp.1435-1440
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    • 2014
  • Nodes in WSNs must operate under limited energy resource. Controlling access to the channel in WSNs plays a key role in determining channel utilization and energy consumption. This paper introduces a priority-based time slot allocation protocol for hybrid TDMA/CSMA MAC in WSNs. This protocol combines both TDMA and CSMA techniques while introducing prioritization by (m,k)-firm constraint. The performance of this protocol is obtained through simulations for various number of nodes and show significant improvements in delay and packet delivery ratio compared to S-MAC.

Hybrid Inter-Cell TDMA/Intra-Cell CSMA Architecture for Wireless Sensor Networks (무선 센서 네트워크를 위한 하이브리드 Inter-Cell TDMA/Intra-Cell CSMA 아키텍처)

  • Lee, Han-Sun;Won, Kwang-Ho;Lee, Sang-Shin;Chung, Kwang-Sue
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.9
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    • pp.690-694
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    • 2009
  • In this paper, we propose a hybrid MAC architecture for reducing energy consumption and maximizing network lifetime in wireless sensor networks. For this purpose, the hybrid MAC architecture is proposed for energy efficient by combining inter-cell TDMA and intra-cell CSMA scheme. Based on the ns-2 simulation result, we prove that the proposed architecture improves energy efficiency as compared with CSMA and TDMA.