• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.751-758
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• 2020

As the application fields using various types of communication, including the Internet of Things, have emerged, the form of communication has been diversified. Some applications require fast feedback and the others continue to send data regardless of whether it is received or not. Transmitting data in one way can be acknowledged by the opposite direction response. These information exchanges form a two-way communication. For applications that need to issue commands remotely, such as network control systems, it is important to give a fast response because the sender decides the next action based on the response from the recipient. In this paper, we propose the base station (BS) cooperation to improve the latency performance of the two-way communication in cellular networks. We design the two-way communication strategy utilizing cooperating BSs with the same direction of traffic as well as bidirectional traffic. We show that the proposed scheme improves the latency performance than the previous works.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1903-1909
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• 2007

As the electric power industry has been revolutionarily transformed such that the distributed energy resources have been interconnected with power systems and a variety of energy service providers have been appeared, the need of Consumer Energy Portal as a core of two-way communication and service infrastructure between power suppliers and consumers has been gradually increased. Consumer Energy Portal can be thought of as a combination of hardware and software enabling two-way communication between energy service providers and equipment within the consumers' premises or a physical and logical link between consumers' in-building networks and wide-area access networks. In other words, Consumer Energy Portal can make the way the power industry has been traditionally operated the web-based way, enabling two-way interactions between energy service providers and consumers and mutual networking between end users' equipment. Thus, Consumer Energy Portal can be a kind of Service portal that provides new value-added services and efficient power operations that in the past. In this paper, for ESPs' integrated resources management, demand side management and value-added service provision, we have established the two-way access network that can gather real-time metering data using ZigBee technology and control physically networked equipment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.941-943
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• 2013

A standardized communication protocol is required to exchange the data of electric charge and current-using electric power through the two-way communications between the smart meter and electric power supplier. In this paper, a two-way communications technologies is designed for control technologies and de/registration services of electric equipment, and the international communication protocols is applied to the communications technologies.

• Journal of Information Technology Services
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• v.11 no.2
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• pp.93-106
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• 2012

Recently, a Game Shut-down policy, partially limiting the time for the use of online game service, has been implemented in order to protect the youth from the excessive use of games by limiting their access to games in the late hours, based on the serious side effects of online games on the youth. However, the effectiveness of a Game Shut-down policy becomes a social issue. Thus, this study aims to investigate the alternative policies through the levels of the communications suggested by the theory of excellence, for the successful implementation of the policy. As a result of the study, the government and students, the recipient of those policies, need to strengthen their two-way communication in respect of the Game Shut-down policy, breaking from the existing views on the perception. The problem is that the current government's way of the communication for the Game Shut-down policy is one-way and it is aiming at achieving the objectives only. Thus, the communication in this manner will cause the side effect. 'the opportunistic violation of the system in the future', even if the students seemingly accept the system. Two-way communication will enhance the motivation for the voluntary acceptance of the system and lower the motivation for the opportunistic violation of the system. Thus, the government needs to strengthen two-way communication in the future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3409-3422
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• 2014

The frequency spectrum available for the wireless communication is extremely crowded. In order to improve the spectral efficiency, the two-way relay networks have aroused great attention. A simple $N^{th}$ best-relay selection criterion for the opportunistic two-way relay networks is proposed, which can be implemented easily by extending the distributed timer technique in practice, since the proposed criterion is mainly based on the channel gains. The outage performance of the proposed relay selection scheme is analyzed under the outdated channel state information (CSI), and a tight closed-form lower bound and asymptotic value of the outage probability over Rayleigh fading channels are obtained. Simulation results demonstrate that the tight closed-form lower bound of the outage probability very closely matches with simulated ones in the whole SNR region, and the asymptotic results provide good tight approximations to the simulation ones, especially in the high SNR region.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.4087-4102
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• 2014

Two-way relaying is an effective way of improving system spectral efficiency by making use of physical layer network coding. However, energy efficiency in OFDM-based bidirectional relaying with asymmetric traffic requirement has not been investigated. In this study, we focused on subcarrier transmission mode selection, bit loading, and power allocation in a multicarrier single amplified-and-forward relay system. In this scheme, each subcarrier can operate in two transmission modes: one-way relaying and two-way relaying. The problem is formulated as a mixed integer programming problem. We adopt a structural approximation optimization method that first decouples the original problem into two suboptimal problems with fixed subcarrier subsets and then finds the optimal subcarrier assignment subsets. Although the suboptimal problems are nonconvex, the results obtained for a single-tone system are used to transform them to convex problems. To find the optimal subcarrier assignment subsets, an iterative algorithm based on subcarrier ranking and matching is developed. Simulation results show that the proposed method can improve system performance compared with conventional methods. Some interesting insights are also obtained via simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.565-581
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• 2019

This paper investigates the wireless powered two way relay network (WPTWRN), where two single-antenna users and one single-antenna relay firstly harvest energy from signals emitted by a multi-antenna power beacon (PB) and then two users exchange information with the help of the relay by using their harvested energies. In order to improve the energy transfer efficiency, energy beamforming at the PB is deployed. For such a network, to explore the performance limit of the presented WPTWRN, an optimization problem is formulated to obtain the achievable rate region bounds by jointly optimizing the time allocation and energy beamforming design. As the optimization problem is non-convex, it is first transformed to be a convex problem by using variable substitutions and semidefinite relaxation (SDR) and then solve it efficiently. It is proved that the proposed method achieves the global optimum. Simulation results show that the achievable rate region of the presented WPTWRN architecture outperforms that of wireless powered one way relay network architecture. Results also show that the relay location has significant impact on achievable rate region of the WPTWRN.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.1129-1140
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• 2017

Unidirectional data transmission system, which allows physical one way transmission, removes the backward link physically to prevent the intrusion from the outside through the network. However, the system is difficult to apply to the environment requiring either backward transmissions or bi-directional communications. In this paper, we proposed Limited Two-way communications system, called as LimTway, which only allows outbound TCP two-way communications. LimTway uses two one-way links(forward, backward). While the forward one-way link is staying to be activated so that an allowed outbound UDP traffic could be transmitted one-way always, the backward one-way link is activated while allowed outbound TCP sessions are established. In order to prevent the intrusion from the outside during the period, the software of LimTway is designed to allow only the transmissions of both outbound TCP two-way communication traffics and outbound UDP traffics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1279-1300
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• 2017

In the interweave cognitive networks, the interference from the primary user degrades the performance of the cognitive user transmissions. In this paper, we propose an adaptive cooperation scheme in the interweave cognitive networks to improve the performance of the cognitive user transmissions. In the proposed scheme for the bidirectional communication of two end-source cognitive users, the bidirectional communication is completed through the non-relay direct transmission, the one-way relaying cooperation transmission, and the two-way relaying cooperation transmission depending on the limited feedback from the end-sources. For the performance analysis of the proposed scheme, we derive the outage probability and the finite-SNR diversity multiplexing tradeoff (f-DMT) in a closed form, considering the imperfect spectrum sensing, the interference from the primary user, and the power allocation between the relay and the end-sources. The results show that compared with the direct transmissions (DT), the pure one-way relaying transmissions (POWRT), and the pure two-way relaying transmissions (PTWRT), the proposed scheme has better outage performance. In terms of the f-DMT, the proposed scheme outperforms the full cooperation transmissions of the POWRT and PTWRT.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.65-71
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• 2009

The end of the 1990s due to the rapid development of Internet communications and two-way communication advertising, public relations, online music, video, movies, e-Book, and distribution of digital content is actively underway. The combination of Internet and TV, as well as born of IPTV and interactive digital content industry's future has become a key industry. However, these two-way communication that illegal adult sites, illegal Bulletin, illegal Ads, PR, shopping mall, illegal music copying, video replication, such as negative due to the emergence of IPTV and is always around us and should be recognized. For example, on the Internet, which has been operating in the ocean sounds from the music copyright issue, the prosecution decided to prosecute because of the digital cultural content, copyright issues has become an important issue. Status and issues of this paper to learn the digital content, using intelligence to solve these problems, two-way communication advertising, public relations and practice of digital content, practices and courses of students vulnerable to offers for the analysis simulation.