• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.54-67
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• 2006

Low Rate WPAN (Wireless Personal Area Network) designed for low power and low cost wireless communication is an important technology to realize ubiquitous environment. IEEE 802.15.4 and ZigBee Alliance recommend the SKKE (Symmetric-Key Key Establishment) protocol for key establishment and management. The SKKE algorithm has security weakness such as the absence of authentication process or electric signature in key generation and exchange when devices join the role of coordinators. In this paper, we propose new key establishment and security algorithm based on public key encryption to solve low rate WPAN security problems. Also, to improve PLC AMR system's weaknesses in communication reliability and security, we propose a new AMR system model based on IEEE 802.15.4 and we apply our security algorithm to AMR profile for security enhancement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.8
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• pp.683-691
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• 2013

This paper address a new scheme that alleviates the packet collision problem caused by contentions among nearby coordinators (CNs) in IEEE 802.15.4 meshed sensor networks. In existing studies, the number of retransmissions is reduced by adjusting the proper backoff period (BP) of sensor nodes, or unnecessary energy consumption is diminished by increasing channel utilization efficiently based on traffic load. In contrast, the proposed scheme avoids contentions among nearby CNs, thereby it enhances the energy efficiency of sensor nodes. To achieve this, the proposed scheme separates the starting points of CNs' contention periods and reduces contentions and collisions among overlapping CNs. According to our simulation results, the proposed scheme shows improved performance in terms of energy consumption, throughput, the number of collisions, and average delay for all conditions.

• The Journal of the Korea Contents Association
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• v.16 no.10
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• pp.299-310
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• 2016

In this paper, we perform analysis of the performance of low-power communication technology, IEEE 802.15.4 MAC (Media Access Control) protocol used in internet of things. Wide variety of devices in internet of things generate different kinds of traffic characteristics and heterogeneous traffic environment is therefore considered in contrast to existing works. With the help of the Markov chain the performance of the protocol is derived as a function of the MAC parameters and based on the results a framework to determine energy-efficient optimal MAC parameters for applications in real time is proposed. Proposed method is shown to be more efficient in terms of energy consumption through performance comparison over application scenarios compared to operation with fixing MAC parameters, and its practicability on small devices with limited computing power is verified through evaluating the accuracy and speed of the proposed framework.

• The Journal of the Korea Contents Association
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• v.16 no.11
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• pp.83-90
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• 2016

In this paper, we performed the analysis of transmission performance for Collision Free Period(CFP) supported by the low-power communication technology, IEEE 802.15.4 MAC (Media Access Control). For the analysis, periodic traffic, original service target of CFP, is considered and, according to the Quality of Service required, packet arrival pattern to MAC layer is categorized as batch and non-batch, and analysis on throughput, delay, and energy is performed for those patterns. On the basis of the obtained analysis, performance comparison with Collision Avoidance Period(CAP) is carried out for the health care applications that generate periodic traffic such as Pedometer, ECG, EMG. The evaluation confirms that CFP is more energy efficient for healthcare applications that generate periodic and time-critical traffic and moreover for the application with high bandwidth requirement CFP achieves up to 46% energy savings compared to CAP.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.750-759
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• 2012

This paper addresses the collision resolution issue to enhance the performance of wireless sensor networks based on IEEE 802.15.4 slotted CSMA/CA. Some solutions in existing work try to solve this issue by adjusting Backoff Exponent (BE) value or Backoff Period (BP). In contrast to the existing solutions, the proposed scheme in this paper aims at providing high system throughput, but also achieving efficient energy consumption of sensor nodes by using Preamble Address (PA). For this, in the proposed scheme, only one sensor node begins data packet transmission by performing PA contention phase with other nodes before sending each data packet. Our simulation results show that the proposed scheme outperforms existing algorithms in terms of energy consumption and throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2B
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• pp.215-224
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• 2010

A container security device (CSD) monitors intrusions through the cargo door; it is a reduced function device that uses IEEE 802.15.4 with a beacon mode. However, in the beacon mode, the CSD consumes too much battery power in periodical idle listening and sensing trials. Moreover, the CSD cannot send the message to the CSD reader actively, and it makes big latency problem. Therefore, we propose a low-power CSD to reduce the unnecessary power consumption. The proposed CSD follows the requirements of the U.S. Department of Homeland Security, and reduces battery consumption through a power-efficient hardware design, a night-watch mechanism for low-power operation and low-power sensing to reduce unnecessary monitoring. And the CSD sends alert message to the CSD reader. Simulation results show that our CSD reduces battery consumption by over 70% through the night-watch mechanism and by approximately 80% through the low-power sensing. And the CSD can send the alert message to the remote CSD reader by over 94%.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.319-325
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• 2015

Remarkable advances in wireless communication technology have enabled communications among people who are far away from each other. In recent, the needs of local area voice communication using a wireless system based on low-cost and simple hardware are rapidly rising. However, since these applications require that the multi-users communicate on the same wireless channel in a small area, the existing voice technologies are not suitable for directly applying to these applications. Therefore, in this paper I propose a novel idea enabling multi-user voice communication. In particular, as a short range wireless solution, I employ the IEEE 802.15.4 based on low power and low cost. However, since originally the standard is not developed for voice communication, we extend the original scheme to be suitable for the voice communication by utilizing the extended concept of GTS. The capacity and validity of the proposed scheme are evaluated through quantitative analysis in various voice compression rates.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.57-63
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• 2016

This paper describes implementation of the RF frequency synthesizer with $0.18{\mu}m$ silicon CMOS technology being used as an application of the IEEE802.15.4g SUN sensor node transceiver modules. Design of the each module like VCO, prescaler, 1/N divider, ${\Delta}-{\Sigma}$ modulator, and common circuits of the PLL has been optimized to obtain high speed and low noise performance. Especially, the VCO has been designed with NP core structure and 13 steps cap-bank to get high speed, low noise, and wide band tuning range. The output frequencies of the implemented synthesizer is 1483MHz~2017MHz, the phase noise of the synthesizer is -98.63dBc/Hz at 100KHz offset and -122.05dBc/Hz at 1MHz offset.

• Journal of IKEEE
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• v.22 no.2
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• pp.289-301
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• 2018

IIoT, the IoT technology applied to the industrial field, is being used as a monitoring technology for increasing in production rate and safety of workers. However, monitoring through the construction of IIoT network using Ethernet and RS485 in production lines where dozens to hundreds of machine tools are manufacturing components, have difficulties of infrastructure cost and network flexibility and fluidity. Therefore, in this paper, using IEEE 802.15.4 standard WSN device to construct a Ad-Hoc WSN in the production line. In addition, the transmission period and order of the sensor nodes are set by applying the EtherCAT communication method in which the payload frames are shared by all the sensor nodes. From this, we have overcome the problem of reliability decline and real-time issue due to the packet collision of wireless network and confirmed that it is a wireless network routing method that can be used in the actual industrial field.

• Journal of Broadcast Engineering
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• v.13 no.5
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• pp.612-621
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• 2008

Due to the various constraints such as feasible size of data payload and low transmission power, no technical specifications on the voice communication are included in the Zigbee standard. In this paper, a voice coding technique for application to the IEEE 802.15.4 standard, which is the basis of Zigbee communication, is presented. Here, both high compression and good waveform recovery are essential. To meet those requirements, a multi-stage discrete wavelet transform (DWT) block and a binary coding block consisting of two different pulse-code modulations are exploited. Theoretical analysis and simulation results in an indoor wireless channel show that the voice coder with 2-stage DWT is most appropriate from the viewpoint of compression and waveform recovery. When the line-of-sight component is dominant, the voice coding scheme has good recovery capability even in the moderate signal-to-noise power ratios. Hence, it is considered that the presented scheme will be a technical reference for the future recommendation of voice communication exploiting Zigbee.