• The Journal of the Convergence on Culture Technology
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• v.1 no.3
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• pp.83-85
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• 2015

It has been increased that communicate each other things such as consumer electronics, mobile equipments and wearable computer with serial communication protocol. The conventional method of SPI and I2C high speed serial communication is widely used with 2 pin of clock and data pin. It has been more important than the speed of data transfer to simplify the hardware structure because the IoT components is reduced the hardware complexity. In this paper, we describe the protocol and implementation of serial data transfer with only one pin. The proposed protocol is suitable for the mobile products that send and receive the small amount of data with low speed and low power consumption.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.109-115
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• 2019

Currently, LPWA(Low Power Wide Area) communication technology is widely used due to the development of IoT(Internet of Things) technology. Among the LPWA technologies, LoRaWAN(Long Range Wide Area Network) is widely used in many fields due to its wide coverage, stable communication speed, and low-cost modem module prices. In particular, LoRa(Long Range) can easily construct LoRaWAN with a dedicated gateway. So many organizations are building their own LoRaWAN-based networks. The LoRaWAN Gateway receives the LoRa packet transmitted from an End-device installed in the adjacent location, converts it into the Internet protocol, and sends the packet to the final destination server. Current LoRa Gateway uses a single-hop method, and each gateway must include a communication network capable of the Internet. If it is the mobile communication(i.e., WCDMA, LTE, etc.) network, it is required to pay the internet usage fee which is installed in each gateway. If the LoRa communication is frequent, the user has to spend a lot of money. We propose an idea on how to design a multi-hop protocol which enables packet routing between gateways by analyzing the LoRaWAN communication method implemented in its existing single-hop way in this paper. For this purpose, this paper provides an analysis of the standard specification of LoRaWAN and explains what was considered when such protocol was designed. In this paper, two gateways have been placed based on the functional role so as to make the multi-hop protocol realized: (i) hopping gateway which receives packets from the end-device and forwards them to another gateway; and (ii) main gateway which finally transmits packets forwarded from the hopping gateway to the server via internet. Moreover, taking into account that LoRaWAN is wireless mobile communication, a level-based routing method is also included. If the protocol proposed by this paper is applied to the LoRaWAN network, the monthly internet fee incurred for the gateway will be reduced and the reliability of data transmission will be increased.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.243-246
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• 2015

최근 사물 인터넷(Internet of things) 의 발달에 따라, 스마트 디바이스 간의 네트워크 및 이를 구축할 수 있는 기술에 대한 수요가 급증하고 있다. 이러한 스마트 디바이스 간의 저 전력 저 손실 네트워크(Low power and Lossy network) 환경에서 쓰이는 대표적인 프로토콜로 CoAP(Constrained Application Protocol)가 있으며, 해당 프로토콜은 다양한 네트워크 환경에 유연하게 적용할 수 있도록 패킷 재전송 주기 설정 옵션을 가진다. 하지만 하나의 디바이스에서 네트워크 환경이 패킷 손실 및 지연여부를 구분 할 수 없기 때문에, 네트워크 상태 파악을 위해서는 수신과 응답 양측 디바이스의 패킷 흐름을 확인해야 하는 문제점이 있다. 본 논문에서는 프로토콜의 정보를 기반으로 네트워크 상태를 파악 할 수 있는 새로운 필드 값을 적용하여 CoAP 패킷 재전송 주기를 네트워크 환경의 상태에 따라 동적으로 설정해주는 알고리즘을 제안한다. 제안된 기법은 동적으로 재전송 주기를 설정함으로써, 패킷 손실에 의한 서비스 장애 극복 및 패킷 지연 상황에서의 불필요한 패킷 재전송을 방지하여 에너지 효율성을 향상시키고 서비스 안정성을 보장한다.

• Journal of the Korea Society of Computer and Information
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• v.8 no.3
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• pp.138-143
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• 2003

With information communications and network environments merged wire/wireless networks are generalized. In this viewpoint, WAP is used by communication protocol for the data communication in the field of wireless environment. WTLS developed for the secure communications optimize TLS adapted wireless environment in the TCP/IP internet protocol. But WTLS denote WAP security problem, end-to-end problem, and power consumption, etc. Therefore in this paper we proposed WTLS cryptographic algorithm eliminated WTLS disadvantages. Proposed algorithm solved power consumption, calculated complexity, and security problems because it is not unique but hybrid form.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.586-594
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• 2014

Maximizing the operating time by reducing the power consumption is important factor to operate sensor network under water networks. For efficient power consumption, dynamic voltage scaling method is available. This method operates low frequency when there is no workload. In case of abundant workload, high frequency operation completes hard work within short time, reducing power consumption. For this reason, complex cryptography should be computed in high frequency. In this paper, we apply dynamic voltage scaling method to cryptography and show performance evaluation. With this result, we can reduce power consumption for cryptography in under water communication.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.200-204
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• 2007

The release of IEEE 802.15.4 PHY-MAC standard represents a milestone in developing of commercial wireless sensor network pursuing low power and low cost. In this paper, IEEE 802.15.4 Medium Access Control (MAC) protocol was analysed at the point of power consumption. This analysis measured the amount of the rest of power after transmitting data with beacon enabled mode and the power consumption of each node in the time period. ns-2 simulation is used to verify the analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.792-797
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• 2005

Lighting control switches based on the power line communication technology are developed and extended to incorporate dimming control to provide energy saving and appropriate illumination. The developed switch uses a general purpose microprocessor and associated electronics. Both the power line communication and the dimming function are implemented in one microprocessor, and it enables the low price commercialization. The frequency of the carrier was set at 250kHz considering the transmission data length and signal attenuation in power lines. Tests on prototypes in an low-voltage power lines have shown that the switches have a robust operation characteristics with the length of power lines and the variation of load capacities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.239-246
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• 2014

In the context of wireless sensor networks, one of major issues is energy conservation. For low power communication, by utilizing our experimental results for the relation between clock drift and synchronization interval, we designed a new protocol which can support a wide range of duty cycles for applications with very low traffic rate and insensitive delay. The transmission (TX) node in the protocol synchronizes with the reception (RX) node very before transmitting a packet, and it can adaptively estimate the synchronization error size according to the synchronization interval from minutes to hours. We conducted simulations and a testbed implementation to show the efficacy of the proposed protocol. We found that our protocol substantially outperforms other state-of-the-art protocols, resulting in order-of-magnitude increase in network lifetime over a variety of duty cycles.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.10
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• pp.2006-2013
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• 2015

In this paper we propose a multi-protocol gateway system based on low power wireless communications. The proposed multi-protocol gateway system was designed to allow real-time monitoring and control of the on-site situation through wired and wireless networks by gathering information for streetlight power control and environmental monitoring. The sensing data using multi-sensors with composite processing that selectively used wired or wireless communication (e.g., CDMA, Ethernet (TCP/IP), GPS, etc.) were designed to act as intermediaries that transmitted to the main server through ZigBee. Inaddition, they were designed by separating a CPU board and baseboard to ensure low maintenance cost and ease of hardware replacement. The proposed multi-protocol gateway system's power, impact, continuous operation stability, and immunity test results obtained a normal operation success rate of over 95% and normal continuous operation results. Moreover, in the voltage drop test, instantaneous immunity test, and conductive RF electromagnetic field immunity test, it obtained an average rating result of "A".

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.357-364
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• 2014

The first mission for the IoT based hyper-connectivity communication is developing a device-to-device communication technique in infra-less low-power and lossy networks. 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. 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.