• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8B
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• pp.615-623
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• 2008

Wireless LAN (WLAN) has greatly benefited from the introduction of various technologies, such as MAC protocol and scheduling algorithm. The majority of these technologies focus on fairness or service differentiation. However, it is difficult to use these technologies to provide many benefits to WLAN simultaneously because the current WLAN system only focuses on the provision of a single aspect of QoS. Unfortunately, multimedia applications require both service differentiation and fairness. Therefore, this paper combines Distributed Fair Scheduling (DFS) and Enhanced Distributed Coordinate Function (EDCF), to provide both fairness and service differentiation simultaneously. Furthermore, we show numerical analysis using Markov process. The simulation results demonstrate that F-EDCF outperforms the EDCF, in terms of throughput, fairness, and delay viewpoints.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.1
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• pp.99-104
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• 2014

Nowadays, various researches fulfill in many communication engineering area for B4G (Beyond Forth Generation). Next LTE-A (Long Term Evolution Advanced), MU-MIMO (Multi-User Multi Input Multi Output) method raises to upgrade throughput performance. However, the method of user selection is not decided because of many types and discussions in MU-MIMO system. Many existing methods are powerful for enhancing performance but have various restrictions in practical implementation. Fairness problem is primary restriction in this area. Existing papers emphasis algorithm to increase sum-rate but we introduce an algorithm about dealing with fairness problem for real commercialization implementation. Therefore, this paper introduces new user selection method in MU-MIMO system. This method overcomes a fairness problem in SUS (Semiorthogonal User Selection) algorithm. We can use the method to get a similar sum-rate with SUS and a high fairness performance. And this paper uses a hybrid method with SC-SUS (Superposition Coding SUS) algorithm and SUS algorithm. We find a threshold value of optimal performance by experimental method. We show this performance by computer simulation with MATLAB and analysis that results. And we compare the results with another paper's that different way to solve fairness problem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.547-556
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• 1997

In this paper we suggest a dynamic quota allocation mechansim for B-ISDN(Broadband Integrated Services Digital Network) subscriber networks. The quota adaptation decision based on the number of cells in the transmission queue is made distributively by each node in the ring network. This mechanism provides both fairness and efficiency for it enables each node to adapt its quota under asymmetric traffic condition. The simulation results show that substantial improvements in access delay time and throughput can be achieved with this algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2188-2195
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• 2015

In tactical wireless local area networks, jamming attack can easily occur by sending out continuous radio signals. The damage will be serious when the channel frequency is identical. Since wireless channel environment is open to everyone, the perfect solution for jamming attack does not exist. However, a channel-hopping scheme is well known for mitigating those jamming attacks. In this paper, I consider various channel-hopping schemes in order to analyze the throughput and fairness performance under smart jammer attack. Also an analytical model is introduced to evaluate the throughput performances of channel-hopping schemes. After analyzing well known channel-hopping schemes, I propose a simple channel-hopping scheme that can enhance fairness significantly at minimal throughput degradation expense.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.83-88
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• 2020

This paper proposes a method of applying an advanced preamble detection technology to wireless sensor nodes and analyzes the trade-off relationship between throughput and fairness that may occur when sensor nodes equipped with the MIM function compete with the legacy IEEE 802.15.4 sensors. Sensor nodes employing the MIM capability have more chances of concurrent transmissions than the legacy IEEE 802.15.4-based sensor nodes, resulting in gains in terms of throughput, whereas the transmission opportunities of 802.15.4 sensor nodes might be limited due to the additional simultaneous transmissions of the MIM sensor nodes. The extensive evaluation results performed under a test environment built using Python program with reflecting the setting value of a commercial sensor node shows MIM sensor nodes outperform up to 40% over the legacy 802.11 sensors. Meanwhile, it was confirmed that a balance can be achieved in terms of throughput and fairness by properly adjusting the concurrent transmission threshold.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.589-596
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• 2019

With the proliferation of intelligent transportation system (ITS) with dedicated short-range communication (DSRC) deployment, there are various applications requiring different throughput and reliability performance. To meet the enhanced throughput requirements in newly generated applications, IEEE 802.11bd is proposed to standardize for support of enhanced throughput and latency, preserving the fairness with previously deployed WLAN V2X devices. One of the main features of IEEE 802.11 bd is 20 MHz transmission to support the high data rate. In this paper, the primary channel selection method is proposed to guarantee the fairness with frame transmissions with 10 MHz bandwith including communications in WLAN V2X devices deployed with IEEE 802.11p. Simulation shows that the proposed channel access method for 20 MHz transmission with primary selection preserves the fairness without the change of channel access method in wide-band transmission.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.6
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• pp.1479-1495
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• 2012

Spectrum scarcity seems to be the most challenging issue to be solved in new wireless telecommunication services. It is shown that spectrum unavailability is mainly due to spectrum inefficient utilization and inappropriate physical layer execution rather than spectrum shortage. Daily increasing demand for new wireless services with higher data rate and QoS level makes the upgrade of the physical layer modulation techniques inevitable. Orthogonal Frequency Division Multiple Access (OFDMA) which utilizes multicarrier modulation to provide higher data rates with the capability of flexible resource allocation, although has widely been used in current wireless systems and standards, seems not to be the best candidate for cognitive radio systems. Filter Bank based Multi-Carrier (FBMC) is an evolutionary scheme with some advantages over the widely-used OFDM multicarrier technique. In this paper, we focus on the total throughput improvement of a cognitive radio network using FBMC modulation. Along with this modulation scheme, we propose a novel uplink radio resource allocation algorithm in which fairness issue is also considered. Moreover, the average throughput of the proposed FBMC based cognitive radio is compared to a conventional OFDM system in order to illustrate the efficiency of using FBMC in future cognitive radio systems. Simulation results show that in comparison with the state of the art two algorithms (namely, Shaat and Wang) our proposed algorithm achieves higher throughputs and a better fairness for cognitive radio applications.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.10
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• pp.299-308
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• 2023

As the spectrum shortage problem has accelerated by the emergence of various services, New Radio-Unlicensed (NR-U) has appeared, allowing users who communicated in licensed bands to communicate in unlicensed bands. However, NR-U network users reduce the performance of Wi-Fi network users who communicate in the same unlicensed band. In this paper, we aim to simultaneously maximize the fairness and throughput of the unlicensed band, where the NR-U network users and the WiFi network users coexist. First, we propose an optimal power allocation scheme based on Monte Carlo Policy Gradient of reinforcement learning to maximize the sum of rates of NR-U networks utilizing rate-splitting multiple access in unlicensed bands. Then, we propose a channel occupancy time division algorithm based on sequential Raiffa bargaining solution of game theory that can simultaneously maximize system throughput and fairness for the coexistence of NR-U and WiFi networks in the same unlicensed band. Simulation results show that the rate splitting multiple access shows better performance than the conventional multiple access technology by comparing the sum-rate when the result value is finally converged under the same transmission power. In addition, we compare the data transfer amount and fairness of NR-U network users, WiFi network users, and total system, and prove that the channel occupancy time division algorithm based on sequential Raiffa bargaining solution of this paper satisfies throughput and fairness at the same time than other algorithms.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.322-331
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• 2013

Wireless Mesh Networks(WMNs) is generally composed of radio nodes in the mesh topology. WMNs consists of mesh client, mesh router and gateway connected to a wired network. Each client and router relay messages to the gateway for communication. WMNs is widely used recently in many areas can provide extended coverage based on multi-hop communication and ubiquitous communication at any time and any location. However the competition and collision between each node to transmit data is inevitable when the same channel is used for transmission. The transmission opportunities and the throughput of nodes located far from gateway decrease more if the communication channel is accessed based on competitive CSMA/CA scheme using DCF(Distributed Coordination Function) provided by IEEE 802.11 MAC. In this paper, we improve the performance of the TCP fairness and throughput of the nodes with more than 2 hops by applying various algorithms for controlling contention window values. Also, we evaluate the performance using ns-2 simulator, According to the results, proposed scheme can enhance the fairness characteristic of each node irrespective of data to the gateway.

• Annual Conference of KIPS
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• 2004.05a
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• pp.1351-1354
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• 2004

기존의 CDMA 1x EV-DO 시스템에서 비실시간 서비스는 Propotional Fairness 알고리즘을 사용해 셀내의 모든 유저에게 fairness를 제공했지만, throughput이 낮았다. 그래서, 이 논문에서는 이를 개선한 cell의 downlink에서 비실시간 서비스를 스케줄링시 fairness를 제공하면서, throughput을 향상시킬 수 있는 방안을 제안하고 구현하였다.