• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8A
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• pp.712-722
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• 2011

Wireless body area network(WBAN) provide communication service in the vicinity of the body. Since WBANs utilize both MICS frequency band for implant medical applications and ISM frequency band for medical and consumer electronics(CE) applications. Therefore, MAC protocols in WBAN should be designed considering flexibility between medical and CE applications. In this paper, we identify the requirements of WBAN MAC protocols and propose a WBAN MAC protocol which satisfies the requirements. In other to provide transmission flexibility for various applications. we present the dynamic CFP allocation and opportunity period. Extensive simulation result show that the proposed protocol achieves improved throughput and latency in WEAN environment cimpared with IEEE 802.15.4.

• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.219-227
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• 2011

The superframe structure of IEEE 802.15.4, an international standard for low rate WPAN, is composed of CAP(Contention access period) and CFP(Contention free period). CAP is the contention-based access period, while CFP is contention-free access period for supporting QoS by allocating fixed bandwidth. The standard can support QoS for only a few devices, because the maximum number of GTSs is 7. Furthermore, as the value of BO (Beacon order) or SO (Superframe order) increases, the size of a time slot increases. This makes it difficult to precisely allocate bandwidth for any device, because the bandwidth is allocated by the unit of GTS. The proposed scheme of this paper can reduce the waste of BW in CFP by adaptively reducing the size of a time slot in CFP as the value of BO or SO increases and increase the number of GTSs to 127 by modifying the standard. The performance analysis shows that the proposed scheme can dramatically increase the bandwidth utilization during the CFP when comparing with IEEE 802.15.4.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.246-248
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• 2012

In this paper, we recommend some game theoretical schemes try to get reliability transmission and resource allocation of the contention free period in overlapped WBAN(Wireless Body Area Net works) environment. Cooperative bargaining game is considered to guarantee a reliability conflict-free transmission. We study it by considering the priorty of device and the demand number of allocated timeslots in the CFP (Contention Free Period), and guarantee the least requested timeslots through bargaining between each user.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.1
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• pp.123-140
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• 2011

In this paper, we propose an Energy Efficient Media Access Control (EE-MAC) protocol for wireless sensor networks. The proposed scheme is designed to save power consumption and guarantee quality-of-service for real-time traffic. EE-MAC uses the superframe structure which is bounded by the transmission of a beacon frame and can have an active and an inactive portion. The active period is divided into the contention free period (CFP) for real-time traffic transmission and the contention access period (CAP) for non-real-time traffic transmission. We propose the exclusively allocated backoff scheme which assigns a unique backoff time value to each real-time node based on bandwidth allocation and admission control. This scheme can avoid collision between real-time nodes by controlling distributed fashion and take effect a statistical time division multiple access. We also propose the algorithm to change the duty cycle adaptively according to channel utilization of media depending on network traffic load. This algorithm can prolong network lifetime by reducing the amount of energy wasted on idle listening.