• Title/Summary/Keyword: MAC Frame

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A MAC Protocol for Transmission Power Control in Ad Hoc Networks (애드 혹 네트워크에서 전송파워 제어를 위한 MAC 프로토콜)

  • Hwang, Sungho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.2
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    • pp.878-884
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    • 2013
  • This paper presents a transmission power control MAC protocol that allows terminals to vary transmit power level on data frame basis in ad hoc network. Unlike the IEEE 802.11 approach, we do not use the RTS/CTS packets to silence the neighboring nodes. Instead, channel gain and distance information between transmitter and receiver terminal are inserted in the RTS/CTS packets. These informations are used to dynamically bound the transmission power. Simulation results indicate that, compared to the GMAC, the proposed MAC protocol achieves a increase in the average frame delivery ratio and a decrease in the average frame delay.

A Lightweight Authentication Mechanism for Acknowledgment in LR-WPAN Environment

  • Heo, Joon;Hong, Choong-Seon;Choi, Sang-Hyun
    • Annual Conference of KIPS
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    • 2005.11a
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    • pp.973-976
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    • 2005
  • In IEEE 802.15.4 (Low-Rate Wireless Personal Area Network) specification, a successful reception and validation of a data or MAC command frame can be confirmed with an acknowledgment. However, the specification does not support security for acknowledgment frame; the lack of a MAC covering acknowledgments allows an adversary to forge an acknowledgment for any frame. This paper proposes an identity authentication mechanism at the link layer for acknowledgment frame in IEEE 802.15.4 network. With the proposed mechanism there is only three bits for authentication, which can greatly reduce overhead. The encrypted bit stream for identity authentication will be transmitted to device by coordinator within association process. Statistical method indicates that our mechanism is successful in handling MAC layer attack.

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Cooperative Frame Aggregation in IEEE 802.11n Wireless Networks (IEEE 802.11n 무선 네트워크에서의 협력적 프레임 집약 기법)

  • Song, Tae-Won;Pack, Sang-Heon
    • The KIPS Transactions:PartC
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    • v.17C no.6
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    • pp.485-490
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    • 2010
  • IEEE 802.11n supports two frame aggregation schemes, aggregation for MAC service data unit (A-MSDU) and aggregation for MAC protocol data unit (A-MPDU), to improve throughput at the MAC layer. In this paper, we propose a cooperative frame aggregation (CoFA), which can recover erroneous frames in a cooperative manner based on A-MPDU. Specifically, CoFA receive multiple frames from direct and relay paths, and combined multiple frames jointly. Numerical results show that CoFA outperforms direct transmission and relay transmission over diverse channel conditions.

A MAC Protocol for Integrated Service in the Multi-Hop Ad-Hoc Maritime Communication Network (다중 홉 해양통신망에서 실시간 통합 서비스를 위한 MAC 프로토콜)

  • 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.38A no.7
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    • pp.603-611
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    • 2013
  • In this paper, we propose a new frame structure and the underlying dynamic resource control mechanism to support an integrated service, including a real-time (RT) service that requires to serve the end-to-end delay performance, as well as non-real-time (NRT) service, using Self-Organizing Time Division Multiple Access (SO-TDMA)-based MAC protocol in a multi-hop ad-hoc maritime communication network. The underlying frame structure is dynamically configured by resource allocation to guarantee the average target outage performance of the real-time service. Toward this end, we analyze the average outage probability and its performance is verified for the proposed frame structure by simulation.

Throughput Analysis of ETSI BRAN HIPERLAN/2 MAC Protocol Taking Guard Timing Spaces into Consideration

  • Ko, You-Chang;Son, Yong-Tae;Shin, Yong-Eok;Lee, Hyong-Woo;Cho, Choong-Ho
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.04d
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    • pp.515-517
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    • 2003
  • In this paper we examine the effects of the required portions of guard timing spaces in a MAC frame of ETSI BRAN HIPERLAN/2 system such as inter-mobile guard timing space in UL(Up Link) duration, inter-RCH(Random CHannel) guard timing space, sector switch guard timing space. In particular, we calculate the number of OFDM(Orthogonal Frequency Division Multiplexing) symbols required for these guard timing spaces in a MAC frame. We them evaluate the throughput of HIPERLAN/2 system as we vary parameter such as the guard time values defined in [2], the number of DLCCs(Data Link Control Connections), and the number of RCHs. Finally we show by numerical results that the portions for the 새심 summation of required guard timing spaces in a MAC frame are not negligible, and that they should be properly considered when trying to evaluate the performance of MAC protocol of HIPERLAN/2 system and also when determining the number of RCHs as well as the number of DLCCs in UL PDU trains at an AP/CC(Access Point/Central Controller).

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Multi-Hop MAC Protocol for Wireless Sensor Networks (센서 네트워크를 위한 멀티 홉 MAC 프로토콜)

  • Cho, Kyong-Tak;Bahk, Sae-Woong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.6A
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    • pp.506-514
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    • 2009
  • To minimize energy consumption, most of MAC Protocols in WSNs exploit low duty cycling. Among those, RMAC [4] allows a node to transmit a data packet for multiple hops in a single duty cycle, which is made possible by exploiting a control frame named Pioneer (PION) in setting up the path. In this paper, we present a MAC Protocol called Hop Extended MAC (HE-MAC) that transmits the data packet for more multiple hops in a single duty cycle. It employs an EXP (Explorer) frame to set up the multiple hop transmission, which contains the information of the maximum hop that a packet can be transmitted. With the use of the information in EXP and an internal state of Ready to Receive (RTR), HEMAC extends the relay of the packet beyond the termination of the data period by two more hops compared to RMAC. Along with our proposed adaptive sleeping method, it also reduces power consumption and handles heavy traffic efficiently without experiencing packet inversion observed in RMAC. We analytically obtain the packet delivery latency in HE-MAC and evaluate the performance through ns-2 simulations. Compared to RMAC, HE-MAC achieves 14% less power consumption and 20% less packet delay on average for a random topology of 300 nodes.

An Energy Efficient Mac Protocol for WBAN through Flexible Frame Structure (WBAN 환경에 따른 유동적 상태 전환 Mac Protocol)

  • Choi, J.S.;Kim, J.G.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.7 no.2
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    • pp.35-40
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    • 2013
  • In WBAN environment, it is very important to achieve energy efficiency of master and nodes, At the same time, a master also plays an important role in collecting data from nodes and controlling the nodes. By maintaining a master properly, any kinds of situation can be handled. Therefore, low power MAC protocol between a master and a node is highly required appropriately. We propose an improved MAC protocol by simply changing the frame structure of WBAN system. The simulation results show that the proposed scheme attains a lot of saving of energy consumption of master and each node compared with IEEE 802.15.6 and conventional schemes.

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Dynamic Channel Assignment Scheme Based on the Number of Success and Collision of Random Channel in HIPERLAN/2 (HIPERLAN/2에서 랜덤채널의 성공수와 충돌수에 기반한 동적 채널할당 방안)

  • Lim, Seog-Ku
    • Journal of Digital Contents Society
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    • v.12 no.3
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    • pp.347-353
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    • 2011
  • In HIPERLAN/2, the radio channels are assigned by AP(Access Point) that is centrally operated and the MAC protocol is based on TDMA/TDD. Mobile terminal that data transmission is necessary to uplink requests radio resource to AP through RCH channel. The changing number of RCHs in each MAC frame is important because too many RCHs may result in a waste of radio resources and too few RCHs may result in many access collisions and prolong time that connect to AP. Hence the number of RCH should be allocated properly according to traffic. From these point, this paper proposes an scheme that dynamically assigned the number of RCH which is based on the number of success and collision of message in previous MAC frame. To prove efficiency of proposed scheme, lots of simulations are conducted and analyzed.

Efficient RCH Assignment Scheme in HiperLNA/2 WLAN (HiperLAN/2 무선랜에서 효율적인 RCH 할당방안)

  • Lim, Seog-ku
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.987-990
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    • 2009
  • The MAC protocol of HiperLAN/2 is based on TDMA/TDD. The radio channels are assigned by AP(Access Point) that is centrally operated. Mobile terminal that data transmission is necessary to uplink requests radio resource to AP through RCH channel. The changing number of RCHs in each MAC frame is important because too many RCHs may result in a waste of radio resources and too few RCHs may result in many access collisions and prolong time that connect to AP. Therefore, number of RCH should be allocated properly according to traffic. From these viewpoint, this paper proposes an advanced scheme that dynamically changed the number of RCH which is based on the number of success and collision of RR message in previous MAC frame. To prove efficiency of proposed scheme, a lots of simulations are conducted and analyzed.

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Terminal-Assisted Hybrid MAC Protocol for Differentiated QoS Guarantee in TDMA-Based Broadband Access Networks

  • Hong, Seung-Eun;Kang, Chung-Gu;Kwon, O-Hyung
    • ETRI Journal
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    • v.28 no.3
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    • pp.311-319
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    • 2006
  • This paper presents a terminal-assisted frame-based packet reservation multiple access (TAF-PRMA) protocol, which optimizes random access control between heterogeneous traffic aiming at more efficient voice/data integrated services in dynamic reservation TDMA-based broadband access networks. In order to achieve a differentiated quality-of-service (QoS) guarantee for individual service plus maximal system resource utilization, TAF-PRMA independently controls the random access parameters such as the lengths of the access regions dedicated to respective service traffic and the corresponding permission probabilities, on a frame-by-frame basis. In addition, we have adopted a terminal-assisted random access mechanism where the voice terminal readjusts a global permission probability from the central controller in order to handle the 'fair access' issue resulting from distributed queuing problems inherent in the access network. Our extensive simulation results indicate that TAF-PRMA achieves significant improvements in terms of voice capacity, delay, and fairness over most of the existing medium access control (MAC) schemes for integrated services.

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