• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4662-4677
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• 2018

The dynamic opportunistic device-to-device (DO-D2D) network will frequently emerge in the fifth generation (5G) wireless communication due to high-density and fast-moving mobile devices. In order to improve the Quality of Experience (QoE) of users with different computing capacity devices in the DO-D2D network, in this paper, we focus on the study of how to reduce the packets retransmission delay and satisfy heterogeneous devices. To select as many devices as possible to transmit simultaneously without interference, the concurrent transmitters-selecting algorithm is firstly put forward. It jointly considers the number of packets successfully received by each device and the device's connectivity. Then, to satisfy different devices' demands while primarily ensuring the base-layer packets successfully received by all the devices, the layer-cooperation instantly decodable network coding is presented, which is used to select transmission packets combination for each transmitter. Simulation results illustrate that there is an appreciable retransmission delay gain especially in the poor channel quality network compared to the traditional base-station (BS) retransmission algorithm. In addition, our proposed algorithms perform well to satisfy the different demands of users with heterogeneous devices.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2631-2649
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• 2021

Device-to-Device (D2D) communication is one of the enabling technologies for 5G networks that support proximity-based service (ProSe) for wireless network communications. This paper proposes a power control algorithm based on the Nash equilibrium and game theory to eliminate the interference between the cellular user device and D2D links. This leadsto reliable connectivity with minimal power consumption in wireless communication. The power control in D2D is modeled as a non-cooperative game. Each device is allowed to independently select and transmit its power to maximize (or minimize) user utility. The aim is to guide user devices to converge with the Nash equilibrium by establishing connectivity with network resources. The proposed algorithm with pricing factors is used for power consumption and reduces overall interference of D2Ds communication. The proposed algorithm is evaluated in terms of the energy efficiency of the average power consumption, the number of D2D communication, and the number of iterations. Besides, the algorithm has a relatively fast convergence with the Nash Equilibrium rate. It guarantees that the user devices can achieve their required Quality of Service (QoS) by adjusting the residual cost coefficient and residual energy factor. Simulation results show that the power control shows a significant reduction in power consumption that has been achieved by approximately 20% compared with algorithms in [11].

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.10
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• pp.885-894
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• 2012

Currently, Demand of data traffic has rapidly increased by popular of smart device. It is very difficult to accommodate demand of data traffic by limited resource of base station (BS). To solve this problem, method has proposed that the Device-to-Device (D2D) reduce frequency overload of the BS and all of the user equipment (UE) inside the BS and neighbor BS don't allow communicating directly to BS. However, in LTE-Advance system cellular link and sharing radio resources of D2D link, the strong interference of the cellular network is still high. So we need to eliminate or mitigate the interference. In this paper, we use the transmission power control method and Soft Frequency Reuse (SFR) resource allocation method to mitigate the interference of the cellular link and D2D link. Simulation results show that the proposed scheme has high performance in terms of Signal to Noise Ratio (SINR) and system average throughput.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.219-220
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• 2011

본 논문은 LTE-Advanced 망에서의 D2D(Device-to-Device) 통신을 효율적으로 하기 위한 주파수 할당 절차를 소개하고 그 메커니즘을 제안하였다. 제안한 메커니즘은 기지국에서 셀 내 주파수의 상태에 따라 주파수에 우선순위를 적용한 뒤, 높은 우선순위를 가지는 주파수를 D2D 통신에 할당한다. 성능평가에서는 D2D 통신, 주파수 할당 메커니즘을 적용하지 않은 D2D 통신, 주파수 할당 메커니즘을 적용한 D2D 통신의 처리량을 비교하여 제안한 메커니즘의 우수성을 증명하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.557-559
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• 2014

We propose an efficient resource allocation scheme based on interference awareness for D2D (Device-to-Device) communication in cellular networks. Recently, many researchers have studied how to allocate frequency resources to DUE (D2D User Equipment) with full interference channel information. However, it is difficult to assume a scenario where instantaneous interference information between the CUE (Cellular UE) and DUE is known to the BS (Base Station). To tackle this problem, we proposed in this paper a new scheme in which the BS allocates a resource to CUE and DUE without a full channel information and can aware interference based on only transmit power and distance between UEs. Simulation results show effectiveness of the proposed scheme.

• Journal of IKEEE
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• v.27 no.4
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• pp.579-586
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• 2023

Device-to-Device communication is a very important essential feature in PPDR(Public Protection Disaster Relief) communication, but it has not yet been implemented in LTE-based PPDR communication. In this study, we propose a solution to implement the LTE-based domestic PPDR communication network by evolving the terminals into D2D in-band terminals and effectively operating the current PS-LTE terminals and digital radios in the transitional period.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.7
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• pp.571-579
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• 2013

This paper proposes an energy-efficient mode selection and power allocation scheme in device-to-device (D2D) communication system as an underlay coexistence with cellular networks. We analyze the energy efficiency which is defined as the summation of the energy efficiencies for all devices. The proposed scheme consists of two steps. First, we calculate the transmission power maximizing the energy efficiency for all possible modes of each device. Although the proposed power cannot maximize the system capacity, we prove that the proposed transmission power is the optimal power which maximizes the energy efficiency. In the second step, we select a mode which has the maximal energy efficiency among all possible mode combinations of the devices. Then we can jointly obtain the transmission power and the mode which can maximize the energy efficiency. The proposed scheme has the optimal performance with respect to the energy efficiency and outperforms the conventional schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1521-1531
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• 2015

According to the service attributes, D2D communications establish 1-1, or 1-n channels and require the differentiated device discovery technology. This paper proposes a sector-based device discovery mechanism for 1-n D2D communication scenario in LTE-Advanced networks that a disaster happened. Our proposal is a mechanism that can extend the coverage in a disaster situation which a number of devices(survivors) need to be discovered in a short time. In the single cell environment, a larger discovery coverage can be obtained, and in the multi-cell, it is possible to mitigate the interference with adjacent links due to sector-based coverage control. Through a set of simulations, we have confirmed that our proposal has better performance in the number of devices discovered and the interference than the legacy broadcast device discover mechanism.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.12
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• pp.4946-4960
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• 2020

In a device-to-device (D2D) underlaid cellular network, there exist two types of co-channel interference. One type is inter-layer interference caused by spectrum reuse between D2D transmitters and cellular users (CUEs). Another type is intra-layer interference caused by spectrum sharing among D2D pairs. To mitigate the inter-layer interference, we first derive the interference limited area (ILA) to protect the coverage probability of cellular users by modeling D2D users' location as a Poisson point process, where a D2D transmitter is allowed to reuse the spectrum of the CUE only if the D2D transmitter is outside the ILA of the CUE. To coordinate the intra-layer interference, the spectrum sharing criterion of D2D pairs is derived based on the (signal-to-interference ratio) SIR requirement of D2D communication. Based on this criterion, D2D pairs are allowed to share the spectrum when one D2D pair is far from another sufficiently. Furthermore, to maximize the energy efficiency of the system, a resource allocation scheme is proposed according to weighted graph coloring theory and the proposed ILA restriction. Simulation results show that our proposed scheme provides significant performance gains over the conventional scheme and the random allocation scheme.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.18-25
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• 2016

In D2D communications underlaying a multicell network, it is of primary importance to ensure coexistence of cellular links and D2D links with minimal interference. Therefore, resource allocation scheme for D2D links should be designed to limit the interference between cellular links and D2D links. In this paper, we propose an effective resource allocation scheme for multiple D2D links which share the uplink spectrum resource with cellular users in a multicell network. Under the assumption that the locations of users are known to the base station, the proposed scheme allocates cellular resources to D2D links, such that the interference between a cellular link and multiple D2D links is minimized. In particular, we compute two constants from the path loss model and then use the constants to protect both cellular and D2D links. Simulation results are provided to verify the performance of the proposed scheme.