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Analysis of IEEE 802.15.4 Beacon-Enabled MAC Protocol Nga Dinh; Sangsoon Lim
International Journal of Electrical and Computer Engineering (IJECE) Vol 6, No 3: June 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (396.952 KB) | DOI: 10.11591/ijece.v6i3.pp1122-1132

Abstract

This paper aims to develop several mathematical models to study medium access control (MAC) protocol in the IEEE 802.15.4 beacon-enabled mode with star topology. In particular, the MAC protocol which employs a slotted carrier-sense multiple access with collision avoidance (CSMA/CA) algorithm used in the contention access period (CAP) of a superframe is modelled. The analysis studies the effectiveness of the CSMA/CA algorithm and provides explicit mathematical expressions for power consumption, access delay, and data frame drop probability. The proposed models precisely follow CSMA/CA algorithm in MAC protocol of beacon-enabled mode and differ from those previously published in the literature as 1) they are derived based on data frame generation rate of end devices, 2) they provide a completed expression for frame access delay, and 3) lowpower states of end devices are considered for power efficiency evaluations. The paper shows how power consumption of end devices is improved on the balance with data frame delay. The validity of the proposed models is confirmed and complemented by extensive simulations.
EETA: An Energy Efficient Transmission Alignment for Wireless Sensor Network Applications Sangsoon Lim; Hayoung Oh
International Journal of Electrical and Computer Engineering (IJECE) Vol 6, No 5: October 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (220.599 KB) | DOI: 10.11591/ijece.v6i5.pp2345-2351

Abstract

Energy conserving MAC protocols performing adaptive duty-cycling mechanism have been widely studied to improve the energy efficiency in Wireless Sensor Networks (WSNs). In particular, several asynchronous Low Power Listening (LPL) MAC protocols such as B-MAC, X-MAC and ContikiMAC transmit a long preamble or consecutive data packets for an efficient rendezvous between senders and receivers. However, the rendezvous results in the challenging problem of unnecessary channel utilization since the senders occupy a large portion of the medium. Furthermore, when a traffic generation time overlaps with other neighbouring nodes, they frequently encounter spatially-correlated contention incurring excessive channel contention. In this paper, we propose a novel traffic distribution scheme called an Energy Efficient Transmission Alignment (EETA), that shifts a traffic generation time of the application layer. By using a MAC layer feedback including contention information, the cross-layer framework determines whether the node delays its transmission or not. EETA is robust from the heavy contending environment due to its traffic distribution feature. We evaluate the performance of EETA through diverse experiments on the TelosB platform. The results show that EETA improves the overall energy efficiency by up to 35%, and reduces the latency by up to 48% compared to the existing scheme.
Light-weight Routing Protocol in IoT-based Inter-Device Telecommunication Wireless Environment Hayoung Oh; Sangsoon Lim
International Journal of Electrical and Computer Engineering (IJECE) Vol 6, No 5: October 2016
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (519.963 KB) | DOI: 10.11591/ijece.v6i5.pp2352-2361

Abstract

The primary task for IoT-based hyper-connectivity communications lies in the development of direct communications technique among IoT devices in RPL (Routing Protocol for Low-Power and Lossy Networks) environment without the aid from infras such as access points, base stations etc. In a low-power and lossy wireless network, IoT devices and routers cannot keep the original path toward the destination since they have the limited memory, except for a limited number of the default router information.. Different from the previous light-weight routing protocols focusing on the reduction of the control messages, the proposed scheme provides the light-weight IPv6 address auto-configuration, IPv6 neighbor discovery and routing protocol in a IoT capable infra-less wireless networks with the bloom filer and enhanced rank concepts. And for the first time we evaluate our proposed scheme based on the modeling of various probability distributions in the IoT environments with the lossy wireless link. Specifically, the proposed enhanced RPL based light-weight routing protocol improves the robustness with the multi-paths locally established based on the enhanced rank concepts even though lossy wireless links are existed. We showed the improvements of the proposed scheme up to 40% than the RPL based protocol.