• Journal of Communications and Networks
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• v.18 no.2
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• pp.218-226
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• 2016

Coordination among users is an inevitable but time-consuming operation in wireless networks. It severely limit the system performance when the data rate is high. We present FC-MAC, a novel MAC protocol that can complete a contention within one contention slot over a joint frequency-code domain. When a node takes part in the contention, it generates randomly a contention vector (CV), which is a binary sequence of length equal to the number of available orthogonal frequency division multiplexing (OFDM) subcarriers. In FC-MAC, different user is assigned with a distinct signature (i.e., PN sequence). A node sends the signature at specific subcarriers and uses the sequence of the ON/OFF states of all subcarriers to indicate the chosen CV. Meanwhile, every node uses the redundant antennas to detect the CVs of other nodes. The node with the minimum CV becomes the winner. The experimental results show that, the collision probability of FC-MAC is as low as 0.05% when the network has 100 nodes. In comparison with IEEE 802.11, contention time is reduced by 50-80% and the throughput gain is up to 200%.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.439-444
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• 2017

Wireless sensor network technology is a rapidly growing technology of ubiquitous computing environment and application and research are being carried out in various fields. The sensor nodes constituting the wireless sensor network maintain the life cycle by using the battery in the distributed network environment, so energy efficiency is more important than QoS requirement. In MAC protocol of IEEE802.15.4, MAC protocol study adaptive to traffic and standardization work emphasizing reliability and efficiency in wireless sensor network environment are underway. but, Wireless sensor networks have the problem that the response speed of the sensor node drops as the energy efficiency decreases. In this paper, we designed the MAC protocol with improved energy efficiency of the whole network by analyzing the MAC protocol of the synchronous method and the hybrid method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1369-1376
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• 2015

A wireless bridge is essential to transmit control and managing information to sensors or instruments from a central integrated ship area network station. In this paper, a WiMedia Distributed-MAC(D-MAC) protocol is adopted for development of a seamless N-Screen wireless service in Indoor and Ship Area Networks. Furthermore, to provide the OSMU(One Source Multi Use) N-screen service through P2P streaming in the seamless D-MAC protocol, a Dynamic Threshold-based Multicast(DTM) technology is proposed and analyzed. For this technology, a new Hard/Soft Vertical Region(HVR-SVR) based time slot allocation and a multicast resource reservation scheme are combined. From simulation results, proposed DTM scheme expands the number of time slots available for unicast and multicast realtime N-Screen reservations with various service time interval requests. Furthermore, it enhances performances in vewpoints of realtime N-Screen data reservation conflict and throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.365-377
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• 2006

We define the incomplete medium sharing system as a multi-channel shared medium communication system where any types of constraints are imposed to the set of channels that may be allocated to any transmitter-receiver node pair. A set of distributed MAC schemes are proposed, all of which are based on the CSMA/CA scheme employed in IEEE 802. 11 WLAN standards. Distributed MAC schemes are proposed in three different forms, which can be differentiated by the number and the location of back-off timers; that is, (1) one timer for all queues destined for different receiver nodes, (2) multiple timers at individual transmission queues, (3) multiple timers for individual channels. Through an extensive set of computer simulations, the performances of the proposed MAC schemes show that the MAC scheme with timers at individual transmission queues outperform the others in terms of throughput and delay for most cases considered. The complexity of the proposed schemes is also compared, and the first scheme obviously turned out to be the simplest, and the complexity of the second and third schemes depends on the number of receiver nodes and the number of channels, respectively.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.263-264
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• 2008

고속 무선 PAN(Personal Area Networks)기술은 10m 이내의 짧은 거리에서 고속으로 대용량의 데이터를 전송하기 위한 기술로, 최근 무선 USB(Wireless Universal Serial Bus)나 HDTV(High Definition TV)와 같은 광대역 멀티미디어 응용 시장을 겨냥한 연구가 IEEE 802.15.3과 WiMedia를 중심으로 활발히 진행되고 있다. [1] 본 논문에서는 WiMedia Alliance에서 제안한 Distributed Medium Access Control (D-MAC)에서 다수 스트림의 QoS 요구를 만족시키는 신뢰성 있는 전송을 위해 데이터 시간 슬롯을 효율적으로 할당하는 알고리즘에 대해 연구하고자 한다.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.4
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• pp.205-208
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• 2009

In this paper, a MAS information management method is proposed for the WiMedia MAC protocol. WiMedia MAC configures a fully distributed network based on Ad-hoc method. WiMedia devices communicate during Superframe which is a communication unit in WiMedia MAC. Each superframe which consist of 256 MASs is divided into two periods, beacon period and data period. In data period, devices communicate with each other using the received channel access information during the beacon period. Due to only $12{\mu}s$ timing allowance between beacon period and data period, the process of the MAS information management cannot be completed in time if entire process handle by software. Therefore, we propose a novel MAS information management method using hardware module. With our proposed method, a WiMedia device is satisfied with the processing time that is required in WiMedia MAC protocol.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.179-182
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• 2005

The Home Phoneline Networking Alliance (HomePNA) 2.0 technology can establish a home network using existing in-home phone lines, which provides a channel rate of 4 - 32 Mbps. HomePNA 2.0 Medium Access Control (MAC) protocol adopts an IEEE 802.3 Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access method, a Quality of Service (QoS) algorithm, and a Distributed Fair Priority Queuing (DFPQ) collision resolution algorithm. In this paper, we analyze the HomePNA 2.0 MAC protocol and propose the architecture of HomePNA 2.0 MAC controller circuit. Then, we present the simulation result of each block included in the HomePNA 2.0 MAC controller.

• Journal of Communications and Networks
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• v.16 no.3
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• pp.311-321
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• 2014

This paper focuses on contention-based medium access control (MAC) protocols used in wireless local area networks. We propose a novel MAC protocol called adaptive backoff tuning MAC (ABTMAC) based on IEEE 802.11 distributed coordination function (DCF). In our proposed MAC protocol, we utilize a fixed transmission attempt rate and each node dynamically adjusts its backoff window size considering the current network status. We determined the appropriate transmission attempt rate for both cases where the request-to-send/clear-to-send mechanism was and was not employed. Robustness against performance degradation caused by the difference between desired and actual values of the attempt rate parameter is considered when setting it. The performance of the protocol is evaluated analytically and through simulations. These results indicate that a wireless network utilizing ABTMAC performs better than one using IEEE 802.11 DCF.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.110-111
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• 2016

디바이스 간 저장콘텐츠에 대해 ASMD (Adaptive Source Multi Device) 무선 N-스크린 공유 서비스를 제공하기 위해서는 콘텐츠 보안성을 갖는 무선 USB 기반 N-스크린 MAC에서의 멀티캐스트 전송기법이 반드시 요구된다. 본 논문에서는 ASMD N-스크린 공유 서비스를 위한 무선 통신 MAC 구조로서, WiMedia Distributed-MAC 기반의 Wireless USB 프로토콜을 적용하고, ASMD N-스크린 통신을 위해, 무선 USB 기반 N-스크린 MAC에서의 멀티캐스트 전송 기술을 제안하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.112-113
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• 2016

디바이스 간 저장콘텐츠에 대해 ASMD (Adaptive Source Multi Device) 무선 N-스크린 공유 서비스를 제공하기 위해서는 콘텐츠 보안성을 갖는 무선 USB 기반 N-스크린 MAC에서의 멀티미디어 전송기법이 반드시 요구된다. 본 논문에서는 ASMD N-스크린 공유 서비스를 위한 무선 통신 MAC 구조로서, WiMedia Distributed-MAC 기반의 Wireless USB 프로토콜을 적용하고, ASMD N-스크린 통신을 위해, 무선 USB 기반 N-스크린 MAC에서의 멀티미디어 전송 기술을 제안하였다.