전자의류통신망을 위한 링크 제어 프로토콜 성능분석

김미리,박경민,최훈,조일연 한국차세대컴퓨팅학회 2011 한국차세대컴퓨팅학회 논문지 Vol.7 No.6

최근 웨어러블 컴퓨터에 대한 연구가 증가하고 있다. 의복에 산재되는 웨어러블 컴퓨터 장치들을 연결하기 위해서는 BAN(Body Area Network)이 필요하다. 본 논문에서는 유선 방식의 BAN, 즉 전자의류통신망에서 실행될 링크 제어 프로토콜을 제안한다. 비동기식 방식의 프로토콜을 설계,구현하였으며 이 프로토콜의 성능을 동기식 방식 링크제어 프로토콜과 비교 분석하였다. 두 방식 중 비동기식 프로토콜이 전반적으로 성능이 우수한 것으로 조사되었다. 두 방식은 각기 특성이 다르므로 BAN 상황에 따라 적절한 프로토콜이 이용되어야 한다. There are many researches going on about a wearable computer. A body area network is required in order to connect peripheral devices and a computer processor which are scattered on a wearable cloths. In this paper, we design and implement an asynchronous link control protocol of a body area network. We show the performance of the asynchronous protocol compared with a synchronous link control protocol. Asynchronous protocol shows better performance in general. Since each protocol has different characteristics, an appropriate protocol must be used depending on a wearable network environment.

Transient Coordinator: a Collision Resolution Algorithm for Asynchronous MAC Protocols in Wireless Sensor Networks

( Sang Hoon Lee ),( Byung Joon Park ),( Lynn Choi ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.12

Wireless sensor networks (WSN) often employ asynchronous MAC scheduling, which allows each sensor node to wake up independently without synchronizing with its neighbor nodes. However, this asynchronous scheduling may not deal with collisions due to hidden terminals effectively. Although most of the existing asynchronous protocols exploit a random back-off technique to resolve collisions, the random back-off cannot secure a receiver from potentially repetitive collisions and may lead to a substantial increase in the packet latency. In this paper, we propose a new collision resolution algorithm called Transient Coordinator (TC) for asynchronous WSN MAC protocols. TC resolves a collision on demand by ordering senders` transmissions when a receiver detects a collision. To coordinate the transmission sequence both the receiver and the collided senders perform handshaking to collect the information and to derive a collision-free transmission sequence, which enables each sender to exclusively access the channel. According to the simulation results, our scheme can improve the average per-node throughput by up to 19.4% while it also reduces unnecessary energy consumption due to repetitive collisions by as much as 91.1% compared to the conventional asynchronous MAC protocols. This demonstrates that TC is more efficient in terms of performance, resource utilization, and energy compared to the random back-off scheme in dealing with collisions for asynchronous WSN MAC scheduling.

Transient Coordinator

이상훈(Sang Hoon Lee),배용수(Yong Soo Bae),최린(Lynn Choi) 한국정보과학회 2013 정보과학회 컴퓨팅의 실제 논문지 Vol.19 No.1

일반적으로 비동기식 센서 네트워크 MAC 프로토콜들은 별도의 충돌회피 알고리즘을 사용하지 않기 때문에 동기식 MAC 프로토콜에 비해 충돌에 의한 성능 저하가 크게 나타난다. 본 논문에서는 충돌에 따른 비동기식 MAC 프로토콜의 성능 저하 문제를 최소화하기 위해 수신 노드가 충돌을 야기한 송신 노드들의 전송 순서를 제어하여 추가적인 충돌을 제거할 수 있는 Transient Coordinator(TC)를 소개한다. TC는 충돌을 감지한 수신 노드가 충돌을 일으킨 송신 노드들에 대한 정보를 수집하고 이를 이용하여 충돌이 발생하지 않는 전송 순서를 각 송신 노드에게 지정하는 방식을 사용한다. 송신 노드들은 지정된 순서에 따라 독점적인 채널 사용 권한을 얻으며 이를 통해 송신 노드간의 충돌을 회피할 수 있다. 시뮬레이션 결과에 대한 분석에 따르면 TC는 반복적인 충돌을 방지하여 그로 인해 낭비되는 시간과 대역폭을 줄일 수 있다. 또한, 이를 통해 기존의 비동기식 MAC 프로토콜에 비해 에너지 소비를 91.1% 줄일 수 있고 각 노드당 평균 데이터 처리량을 약 19.4% 증가시킬 수 있다. 이는 본 논문에서 제안하는 TC가 성능, 자원 활용 및 에너지 효율성 측면에서 기존의 random back-off 방식에 비해 더욱 효율적인 충돌 해결 알고리즘임을 증명한다. Wireless sensor networks (WSN) often employ asynchronous MAC scheduling, which allows each sensor node to wake up independently. Random back-off used by most of asynchronous protocols cannot secure a receiver from potentially repetitive collisions and may lead to a substantial increase in the packet latency. In this paper, we propose a new collision resolution algorithm called Transient Coordinator (TC) for asynchronous WSN MAC protocols. TC resolves a collision on demand by ordering senders’ transmissions when a receiver detects a collision. To coordinate the transmission sequence both the receiver and the collided senders perform handshaking to collect the information and to derive a collision-free transmission sequence, which enables each sender to exclusively access the channel. According to the simulation results, our scheme can improve the average per-node throughput by up to 19.4% while it also reduces unnecessary energy consumption due to repetitive collisions by as much as 91.1% compared to the conventional asynchronous MAC protocols. This demonstrates that TC is more efficient in terms of performance, resource utilization, and energy compared to the random back-off scheme in dealing with collisions for asynchronous WSN MAC scheduling.

Asynchronous 2-Phase Protocol Based on Ternary Encoding for On-Chip Interconnect

오명훈,김성운 한국전자통신연구원 2011 ETRI Journal Vol.33 No.5

Level-encoded dual-rail (LEDR) has been widely used in on-chip asynchronous interconnects supporting a 2-phase handshake protocol. However, it inevitably requires 2N wires for N-bit data transfers. Encoder and decoder circuits that perform an asynchronous 2-phase handshake protocol with only N wires for N-bit data transfers are presented for on-chip global interconnects. Their fundamentals are based on a ternary encoding scheme using current-mode multiple valued logics. Using 0.25 um CMOS technologies, the maximum reduction ratio of the proposed circuits, compared with LEDR in terms of power-delay product, was measured as 39.5% at a wire length of 10 mm and data rate of 100 MHz.

A Survey on Asynchronous Quorum-Based Power Saving Protocols in Multi-Hop Networks

Imani, Mehdi,Joudaki, Majid,Arabnia, Hamid R.,Mazhari, Niloofar Korea Information Processing Society 2017 Journal of information processing systems Vol.13 No.6

Quorum-based algorithms are widely used for solving several problems in mobile ad hoc networks (MANET) and wireless sensor networks (WSN). Several quorum-based protocols are proposed for multi-hop ad hoc networks that each one has its pros and cons. Quorum-based protocol (QEC or QPS) is the first study in the asynchronous sleep scheduling protocols. At the time, most of the proposed protocols were non-adaptive ones. But nowadays, adaptive quorum-based protocols have gained increasing attention, because we need protocols which can change their quorum size adaptively with network conditions. In this paper, we first introduce the most popular quorum systems and explain quorum system properties and its performance criteria. Then, we present a comparative and comprehensive survey of the non-adaptive and adaptive quorum-based protocols which are subsequently discussed in depth. We also present the comparison of different quorum systems in terms of the expected quorum overlap size (EQOS) and active ratio. Finally, we summarize the pros and cons of current adaptive and non-adaptive quorum-based protocols.

Transient Coordinator: a Collision Resolution Algorithm for Asynchronous MAC Protocols in Wireless Sensor Networks

이상훈,박병준,최린 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.12

Wireless sensor networks (WSN) often employ asynchronous MAC scheduling, which allows each sensor node to wake up independently without synchronizing with its neighbor nodes. However, this asynchronous scheduling may not deal with collisions due to hidden terminals effectively. Although most of the existing asynchronous protocols exploit a random back-off technique to resolve collisions, the random back-off cannot secure a receiver from potentially repetitive collisions and may lead to a substantial increase in the packet latency. In this paper, we propose a new collision resolution algorithm called Transient Coordinator (TC) for asynchronous WSN MAC protocols. TC resolves a collision on demand by ordering senders’ transmissions when a receiver detects a collision. To coordinate the transmission sequence both the receiver and the collided senders perform handshaking to collect the information and to derive a collision-free transmission sequence, which enables each sender to exclusively access the channel. According to the simulation results, our scheme can improve the average per-node throughput by up to 19.4% while it also reduces unnecessary energy consumption due to repetitive collisions by as much as 91.1% compared to the conventional asynchronous MAC protocols. This demonstrates that TC is more efficient in terms of performance, resource utilization, and energy compared to the random back-off scheme in dealing with collisions for asynchronous WSN MAC scheduling.

qPALS: Quality-Aware Synchrony Protocol for Distributed Real-Time Systems

( Woochul Kang ),( Lui Sha ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.10

Synchronous computing models provided by real-time synchrony protocols, such as TTA [1] and PALS [2], greatly simplify the design, implementation, and verification of real-time distributed systems. However, their application to real systems has been limited since their assumptions on underlying systems are hard to satisfy. In particular, most previous real-time synchrony protocols hypothesize the existence of underlying fault tolerant real-time networks. This, however, might not be true in most soft real-time applications. In this paper, we propose a practical approach to a synchrony protocol, called Quality-Aware PALS (qPALS), which provides the benefits of a synchronous computing model in environments where no fault-tolerant real-time network is available. qPALS supports two flexible global synchronization protocols: one tailored for the performance and the other for the correctness of synchronization. Hence, applications can make a negotiation flexibly between performance and correctness. In qPALS, the Quality-of-Service (QoS) on synchronization and consistency is specified in a probabilistic manner, and the specified QoS is supported under dynamic and unpredictable network environments via a control-theoretic approach. Our simulation results show that qPALS supports highly reliable synchronization for critical events while still supporting the efficiency and performance even when the underlying network is not stable.

A Survey on Asynchronous Quorum-Based Power Saving Protocols in Multi-Hop Networks

Mehdi Imani,Majid Joudaki,Hamid R. Arabnia,Niloofar Mazhari 한국정보처리학회 2017 Journal of information processing systems Vol.13 No.6

Quorum-based algorithms are widely used for solving several problems in mobile ad hoc networks (MANET)and wireless sensor networks (WSN). Several quorum-based protocols are proposed for multi-hop ad hocnetworks that each one has its pros and cons. Quorum-based protocol (QEC or QPS) is the first study in theasynchronous sleep scheduling protocols. At the time, most of the proposed protocols were non-adaptiveones. But nowadays, adaptive quorum-based protocols have gained increasing attention, because we needprotocols which can change their quorum size adaptively with network conditions. In this paper, we firstintroduce the most popular quorum systems and explain quorum system properties and its performancecriteria. Then, we present a comparative and comprehensive survey of the non-adaptive and adaptivequorum-based protocols which are subsequently discussed in depth. We also present the comparison ofdifferent quorum systems in terms of the expected quorum overlap size (EQOS) and active ratio. Finally, wesummarize the pros and cons of current adaptive and non-adaptive quorum-based protocols.

Wire Optimization and Delay Reduction for High-Performance on-Chip Interconnection in GALS Systems

오명훈,김영우,김학영,김영균,김진성 한국전자통신연구원 2017 ETRI Journal Vol.39 No.4

To address the wire complexity problem in large-scale globally asynchronous, locally synchronous systems, a current-mode ternary encoding scheme was devised for a two-phase asynchronous protocol. However, for data transmission through a very long wire, few studies have been conducted on reducing the long propagation delay in current-mode circuits. Hence, this paper proposes a current steering logic (CSL) that is able to minimize the long delay for the devised current-mode ternary encoding scheme. The CSL creates pulse signals that charge or discharge the output signal in advance for a short period of time, and as a result, helps prevent a slack in the current signals. The encoder and decoder circuits employing the CSL are implemented using 0.25-μm CMOS technology. The results of an HSPICE simulation show that the normal and optimal mode operations of the CSL achieve a delay reduction of 11.8% and 28.1%, respectively, when compared to the original scheme for a 10-mm wire. They also reduce the power-delay product by 9.6% and 22.5%, respectively, at a data rate of 100 Mb/s for the same wire length.

HomePNA 3.0 비동기 MAC 모드의 Collision Management Protocol 성능 분석

김희천,정민영,이태진 한국통신학회 2004 韓國通信學會論文誌 Vol.29 No.7A

Collision Management Protocol (CMP)은 매체 접근 제어 (MAC) 방식이 랜덤 접근 (Random Access)인 HomePNA 3.0 비동기 MAC 모드 시스템으로 구성된 네트워크에서 데이터 프레임 전송 시에 발생하는 충돌을 해결하기 위한 프로토콜이다. 이 프로토콜의 특징은 기존 HomePNA 2.0 시스템의 Distributed fair Priority Queueing (DFPQ) 알고리즘이나 802.11 시스템의 Binary Exponential Backoff (BEB) 알고리즘과는 달리 충돌이 발생한 시스템들의 재 전송 순서를 랜덤 확률로서 결정하지 않고, 각 시스템별로 주어진 Collision Signaling Sequence (CSS) 간을 사용하여 순서를 결정한다. 즉, 재 전송 순서를 사전에 정의된 순서로 결정함으로서 평균적인 충돌 횟수를 최소화 할 수 있게 된다. 본 논문에서는 유선 홈 네트워킹 기술인 HomePNA 3.0의 CMP에 대하여 포화(Saturation) 상태에서의 성능을 분석한다. Collision Management Protocol (CMP) efficiently resolves collisions when data frames are transmitted in networks consisting of HomPNA 3.0 asynchronous MAC mode device with random access. Unlike Distributed Fair Priority Queueing (DFPQ) algorithm in HomePNA 2.0 or Binary Exponential Backoff (BEB) algorithm in IEEE 802.11, order of retransmission is decided according to Collision Signaling Sequence (CSS) values allocated to each device. Thus, CMP can minimize the number of mean collisions because order of retransmission is decided in a deterministic way. In this paper. we evaluate the saturation performance of CMP in HomePNA 3.0 using an analytic method.