• Journal of Computing Science and Engineering
• /
• 제7권4호
• /
• pp.231-241
• /
• 2013

Improvements in wireless sensor network (WSN) technology have resulted in a large number of applications. WSNs have been mainly used for monitoring applications, but they are also applicable to target tracking, health care, and monitoring with multimedia data. Nodes are generally deployed in environments where the exhausted batteries of sensor nodes are difficult to charge or replace. The primary goal of communication protocols in WSNs is to maximize energy efficiency in order to prolong network lifetime. In this paper, various medium access control (MAC) protocols for synchronous/asynchronous and single/multi-channel WSNs are investigated. Single-channel MAC protocols are categorized into synchronous and asynchronous approaches, and the advantages and disadvantages of each protocol are presented. The different features required in multi-channel WSNs compared to single-channel WSNs are also investigated, and surveys on multi-channel MAC protocols proposed for WSNs are provided. Then, existing broadcast schemes in such MAC protocols and efficient multi-hop broadcast protocols proposed for WSNs are provided. The limitations and challenges in many communication protocols according to this survey are pointed out, which will help future researches on the design of communication protocols for WSNs.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권1호
• /
• pp.61-77
• /
• 2017

The most challenging issues in the multi-channel MAC of the IEEE 1609.4 standard is how to handle the dynamic vehicular traffic condition with a high mobility, dynamic topology, and a trajectory change. Therefore, dynamic channel coordination schemes between CCH and SCH are required to provide the proper bandwidth for CCH/SCH intervals and to improve the quality of service (QoS). In this paper, we use a Markov model to optimize the interval based on the dynamic vehicular traffic condition with high mobility nodes in the multi-channel MAC of the IEEE 1609.4 standard. We evaluate the performance of the three-dimensional Markov chain based on the Poisson distribution for the node distribution and velocity. We also evaluate the additive white Gaussian noise (AWGN) effect for the multi-channel MAC coordination scheme of the IEEE 1609.4 standard. The result of simulation proves that the performance of the dynamic channel coordination scheme is affected by the high node mobility and the AWGN. In this research, we evaluate the model analytically for the average delay on CCHs and SCHs and also the saturated throughput on SCHs.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2010년도 춘계학술대회
• /
• pp.728-729
• /
• 2010

Opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel utilization information and selecting appropriate spectrum hole for multi-channel data transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access.

• Journal of information and communication convergence engineering
• /
• 제8권3호
• /
• pp.273-276
• /
• 2010

Opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권8호
• /
• pp.1805-1824
• /
• 2013

Recently, the use of wireless body area networks (WBAN) has been increasing rapidly in medical healthcare applications. WBANs consist of smart nodes that can be used to sense and transmit vital data such as heart rate, temperature and ECG from a human body to a medical centre. WBANs depend on limited resources such as energy and bandwidth. In order to utilise these resources efficiently, a very well organized medium access control (MAC) protocol must be considered. In this paper, a new, adaptive and energy-efficient MAC protocol, entitled isMAC, is proposed for WBANs. The proposed MAC is based on multi-channel communication and aims to prolong the network lifetime by effectively employing (i) a collision prevention mechanism, (ii) a coordinator node (WCN) selection algorithm and (iii) a transmission power adjustment approach. The isMAC protocol has been developed and modelled, by using OPNET Modeler simulation software. It is based on a networking scenario that requires especially high data rates such as ECG, for performance evaluation purposes. Packet delay, network throughput and energy consumption have been chosen as performance metrics. The comparison between the simulation results of isMAC and classical IEEE 802.15.4 (ZigBee) protocol shows that isMAC significantly outperforms IEEE 802.15.4 in terms of packet delay, throughput and energy consumption.

• 센서학회지
• /
• 제22권1호
• /
• pp.18-27
• /
• 2013

Real-time monitoring is one of the prime necessities in a weapon flight test that is required for the efficient and timely collection of large amounts of high-rate sampled data acquired by an event-trigger. The wireless sensor network is a good candidate to resolve this requirement, especially considering the inhospitable environment of a weapon flight test. In this paper, we propose a priority based multi-channel MAC protocol with CSMA/CA over a single radio for a real-time monitoring of a weapon flight test. Multi-channel transmissions of nodes can improve the network performance in wireless sensor networks. Our proposed MAC protocol has two operation modes: Normal mode and Priority Mode. In the normal mode, the node exploits the normal CSMA/CA mechanism. In the priority mode, the node has one of three grades - Class A, B, and C. The node uses a different CSMA/CA mechanism according to its grade that is determined by a signal level. High grade nodes can exploit more channels and lower backoff exponents than low ones, which allow high grade nodes to obtain more transmission opportunities. In addition, it can guarantee successful transmission of important data generated by high grade nodes. Simulation results show that the proposed MAC exhibits excellent performance in an event-triggered real-time application.

• 한국멀티미디어학회논문지
• /
• 제19권11호
• /
• pp.1871-1877
• /
• 2016

In this paper, a Wireless USB (WUSB) protocol is adopted for development of ASMD (Adaptive Source Multi Device) N-screen wireless services. WUSB is the USB technology merged with WiMedia PHY and Distributed-MAC (D-MAC). However, the current WUSB protocol can't provide seamless N-screen streaming services to moving WUSB devices in home network environment. Therefore, to provide the ASMD N-screen services through WUSB based on D-MAC protocol, a channel management scheme is proposed to support seamless mobility between adjacent ASMD groups for wireless IPTV N-screen services. In simulation results, proposed ASMD channel management (ACM) scheme is compared with conventional WUSB channel management scheme in view points of throughput, average path interference and energy consumption according to various numbers of nodes and elapsed simulation times. Through simulation results, it is explained that proposed ASMD channel management (ACM) scheme should be adopted in the WUSB protocol to realize ASMD N-screen wireless services.

• 한국ITS학회 논문지
• /
• 제10권5호
• /
• pp.93-98
• /
• 2011

ITS와 WAVE 등의 도입 및 스마트 폰의 광범위한 보급에 따라 WMN 기술은 IEEE802.11 기반의 AP의 무선접속 범위를 확장시키기 위한 효율적인 기술로서 인정받고 있다. 본 논문에서는 WMN 구현에 있어서 대부분의 메쉬 라우터가 갖고 있는 다중 인터페이스/다중 채널 기능을 활용하여 전반적인 통신 속도 및 처리율 향상을 위한 MAC 프로토콜을 제안하고 컴퓨터 시뮬레이션을 통하여 성능을 검증하였다.

• 한국통신학회논문지
• /
• 제30권8A호
• /
• pp.656-663
• /
• 2005

본 논문에서는 IEEE 802.15.3 High-Rate WPAN (Wireless Personal Area Network) 환경에서 다중 채널을 사용하여 향상된 성능의 MAC 프로토콜을 제안한다. IEEE 802.15.3 High-Rate WPAN은 10m 내외의 거리에서 실시간 비디오 및 대용량 파일 전송을 목적으로 설계된 MAC과 PHY의 표준을 말한다. 현재 표준의 MAC 프로토콜은 하나의 무선 채널을 piconet 내의 모든 DEV가 공유하여 사용한다. 이 중 PNC(Piconet Coordinator)는 TDMA(Time Division Multiple Access)방식으로 DEV들에게 채널타임을 할당한다. 이런 경우 piconet내의 통신하는 DEV의 수가 많아지게 되면 superframe의 길이가 길어져 전송되는 데이터의 aggregate throughput이 떨어지고 QoS(Quality of Service)를 보장하지 못한다. 본 논문에서 하나의 piconet이 여러 개의 채널을 동시에 사용하여 aggregate throughput을 향상시키고 QoS를 보장하는 다중채널 MAC 프로토콜을 제안하고 시뮬레이션을 통해 향상된 성능을 증명한다.

• 전기학회논문지
• /
• 제59권10호
• /
• pp.1914-1916
• /
• 2010

Cognitive radio MAC protocol should allow secondary users to access unused or under-utilized spectrum without interference to primary users. For cognitive MAC protocol, one of the important issues is how to select the channel opportunities for secondary users. In this paper, we propose a novel cognitive MAC protocol to allocate channel opportunities for the secondary users based on the prediction of future availability. The proposed MAC protocol can reduce the interference to primary users and increase throughput using multiple channels.