• Journal of IKEEE
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• v.22 no.4
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• pp.1068-1072
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• 2018

In underwater communications, there are many challenges due to energy limitations, long propagation delay, low data rate, and high power loss, unlike terrestrial RF communications. Especially, the propagation delay of underwater acoustic channel is five orders of magnitude higher than in electro-magnetic terrestrial channels due to the low speed of sound(1,500m/s). Thus, the MAC protocols for terrestrial communications are not suitable for underwater network. In this paper, we studied the considerations for MAC protocol in underwater acoustic channel. Here, we concentrated on CSMA based MAC protocols. From the results, we confirmed that the number of control packets has an important effect on the performance in underwater environment. These results would be useful in designing MAC protocols for underwater acoustic communications.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.341-347
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• 2022

This research is designed to help and offer hold up to complete the requirements of aged and disable in a home. The control approach and the tone approach are used to manage the house appliances. The major organize system implementation in technology of wireless to offer distant contact from a phone Internet Protocol connectivity for access and calculating strategy and appliance remotely. The planned system no need a committed server PC with value of parallel systems and offers a new communication-protocol to observe and control a house environment with more than just the switch functionality. To express the possibility and efficiency of this system, devices like as lights switches, power plugs, and motion-sensors have been included with the planned home control system and supply more security manage on the control with low electrical energy activate method. The rank of switches is corresponding in all this control system whereby all user interfaces indicate the real time existing status. This system planned to manage electrical-appliances and devices in house with reasonably low cost of design, user friendly interface, easily install and provide high security. Research community generally specified that the network "Reconnaissance Attacks" in IPv6 are usually impossible due to they will take huge challenge to carry out address scanning of 264 hosts in an IPv6 subnet."It being deployed of IPv6 shows that it definitely enhances security and undermines the probability". This research of the IPv6 addressing-strategies at present utilizes and planned a new strategy and move toward to "mitigate reconnaissance attacks".

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.581-584
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• 2004

Currently, there are many subscriber access networks: PSTN, ADSL, Cellular Network, IMT200 and so on. To these service providers that provide above network service, it is important that they authenticate and authorize legal subscribers and account for their usage. At present, There exist the several protocols that Support AAA(Authentication, Authorization and Accounting) service : RADIUS, Diameter, TACACS+. Nowadays, RADIUS has used for AAA service widely. It has been extended to support other access network environment. So, we extend RADIUS to support environment of Mobile IPv6. Mobile IPv6 uses IPsec as a security mechanism, basically. But, IPsec is a heavy security technology for small, portable, mobile device. Especially, it is serious at IKE, the subset of IPsec. IKE is a key distribution protocol that distributes the key to the endpoints of IPsec. In t:lis paper, we extend RADIUS to support environment of Mobile IPv6 and simplify the IKE phase of IPsec by AAA system distributing the keys by using its security communication channel. Namely, we propose the key distribution method for IPsec SA establishment between mobile node and home agent. The suggested method was anticipated to be effective at low-power, low computing deyice. Finally, end users feel the faster authentication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.394-400
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• 2013

WoT (Web of Things) was proposed to realize intelligent thing to thing communications using WEB standard technology. It is difficult to adapt security protocols suited for existing Internet communications into WoT directly because WoT includes LLN(Low-power, Lossy Network) and resource constrained sensor devices. Recently, IETF standard group propose to use DTLS protocol for supporting security services in WoT environments. However, DTLS protocol is not an efficient solution for supporting end to end security in WoT since it introduces complex handshaking procedures and high communication overheads. We, therefore, divide WoT environment into two areas- one is DTLS enabled area and the other is an area using lightweight security scheme in order to improve them. Then we propose a mutual authentication scheme and a session key distribution scheme for the second area. The proposed system utilizes a smart device as a mobile gateway and WoT proxy. In the proposed authentication scheme, we modify the ISO 9798 standard to reduce both communication overhead and computing time of cryptographic primitives. In addition, our scheme is able to defend against replay attacks, spoofing attacks, select plaintext/ciphertext attacks, and DoS attacks, etc.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.7 s.349
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• pp.60-71
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• 2006

Group key agreement protocols are designed to allow a group of parties communicating over a public network to securely and efficiently establish a common secret key, Over the years, a number of solutions to the group key agreement protocol have been proposed with varying degrees of complexity, and the research relating to group key agreement to securely communicate among a group of members in integrated wired and wireless networks has been recently proceeded. Both features of wired computing machines with the high-performance and those of wireless devices with the low-power are considered to design a group key agreement protocol suited for integrated wired and wireless networks. Especially, it is important to reduce computational costs of mobile devices which have the limited system resources. In this paper, we present an efficient group key agreement scheme which minimizes the computational costs of mobile devices and is well suited for this network environment and prove its security.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6B
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• pp.423-432
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• 2012

We design a control circuit that can switch input power between a rechargeable battery and a sensor communication device (mote) depending on the operating state of a solar cell as well as the active and sleep mode of a sensor MAC protocol. A mote that simply combines a solarcell and a rechargeable battery may die if there is not sunlight long. A battery is recharged if sunlight is sufficient and a device is in a sleep mode, and it supplies power if sunlight is low and the mote is in an active mode. A mote can switch its input power between solar cell and battery depending on the output level of a solar cell. During this switching, a mote may lose its state information due to the reset of a microprocessor by the transient power-off. A capacitor is used to cope with this phenomenon and also supplies power to a mote during a sleep mode. Experimental results show that the solar cell based mote operates in a very stable manner against the lack of sunlight long.

• Journal of Platform Technology
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• v.12 no.2
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• pp.34-44
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• 2024

This paper proposes a dynamic clock supply control algorithm and a system load power stabilization algorithm that minimizes the power consumption of the sensing system, which accounts for the largest percentage of power consumption in mobile devices, to extend the usage time of the rechargeable battery mounted on the mobile device. The dynamic clock supply control algorithm can reduce the power consumed by the sensing system by configuring a circuit to cut off the power of the sensing system and by recognizing the state of low sensor change and adjusting the measurement cycle. The system load power stabilization algorithm is an algorithm that controls the power of the surrounding module according to the power consumption state, and when it requires a lot of power, it controls the clock supply to stabilize the operation. The experimental results confirmed that applying only the dynamic clock supply control algorithm reduces the power consumed by the sensing system by 17%, and applying only the system load power stabilization algorithm reduces power consumption by 9.3%, enabling it to operate stably in situations that require a lot of power such as image processing. When both algorithms were applied, the power consumption of the battery was reduced by 67% compared to before applying the algorithm. Through this, the reliability of the proposed method was confirmed.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.37-42
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• 2018

Recently, there have been many studies on the IoT environment in which the sensors attached to the equipment automatically transmit and process the site information in real time through the network to control the equipment. The core of such a system is a network for data transmission and reception, and a wired network with wide transmission distance is a priority. However, in the case of a wired network, there is a problem that the time and cost consumed to configure the communication is higher than that of the wireless. In this paper, we propose LPWA - based wireless data transmission system using LPWA and BLE communication to solve this problem. The proposed system collects data from equipment through BLE and transmits data to the server using LPWA. Experimental results show that the spreading factor of maximum length of LPWA is 8, and the minimum length is 9.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.65-70
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• 2024

In recent years, research on smart factory wireless mobile communication technology that wirelessly remotely controls utilities is being actively conducted. The Wi-SUN (Wireless Smart Utility Network) Alliance proposed a Wi-SUN protocol structure suitable for building a platform such as a smart factory as a new wireless communication standardization standard based on EEE802.15.4g/e. It analyzes the performance of the IEEE802.15.4e Receiver Initiated Transmission(RIT) Mode Media Access Control (MAC) in terms of throughput and latency, and looks at considerations for efficient operation. RIT mode shows that as the check interval becomes longer, delay time and throughput decrease. It was shown that as the traffic load increases, if the RIT check interval is shortened, the delay time can be shortened and throughput can be increased. RIT mode has the advantage of low power consumption and has neutral characteristics between IEEE802.15.4 and CSL mode in terms of delay time and throughput.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.4
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• pp.274-280
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• 2011

Due to their rapid growth and new paradigm applications, wireless sensor networks(WSNs) are morphing into low power personal area networks(LoWPANs), which are envisioned to grow radically. The fragmentation and reassembly of IP data packet is one of the most important function in the 6LoWPAN based communication between Internet and wireless sensor network. However, since the 6LoWPAN data unit size is 102 byte for IPv6 MTU size is 1200 byte, it increases the number of fragmentation and reassembly. In order to reduce the number of fragmentation and reassembly, this paper presents a new scheme that can be applicable to 6LoWPAN. When a fragmented packet header is constructed, we can have more space for data. This is because we use 8-bits routing table ill instead of 16-bits or 54-bits MAC address to decide the destination node. Analysis shows that our design has roughly 7% or 22% less transmission number of fragmented packets, depending on MAC address size(16-bits or 54-bits), compared with the previously proposed scheme in RFC4944. The reduced fragmented packet transmission means a low power consumption since the packet transmission is the very high power function in wireless sensor networks. Therefore the presented fragmented transmission scheme is well suited for low-power wireless sensor networks.