• Title, Summary, Keyword: User-fairness

Search Result 126, Processing Time 0.043 seconds

On Power Splitting under User-Fairness for Correlated Superposition Coding NOMA in 5G System

  • Chung, Kyuhyuk
    • International journal of advanced smart convergence
    • /
    • v.9 no.2
    • /
    • pp.68-75
    • /
    • 2020
  • Non-orthogonal multiple access (NOMA) has gained the significant attention in the fifth generation (5G) mobile communication, which enables the advanced smart convergence of the artificial intelligence (AI), the internet of things (IoT), and many of the state-of-the-art technologies. Recently, correlated superposition coding (SC) has been proposed in NOMA, to achieve the near-perfect successive interference cancellation (SIC) bit-error rate (BER) performance for the stronger channel users, and to mitigate the severe BER performance degradation for the weaker channel users. In the correlated SC NOMA scheme, the stronger channel user BER performance is even better than the perfect SIC BER performance, for some range of the power allocation factor. However, such excessively good BER performance is not good for the user-fairness, i.e., the more power to the weaker channel user and the less power to the stronger channel user, because the excessively good BER performance of the stronger channel user results in the worse BER performance of the weaker channel user. Therefore, in this paper, we propose the power splitting to establish the user-fairness between both users. First, we derive a closed-form expression for the power splitting factor. Then it is shown that in terms of BER performance, the user-fairness is established between the two users. In result, the power splitting scheme could be considered in correlated SC NOMA for the user-fairness.

Instantaneous Fairness of TCP in Heterogeneous Traffic Wireless LAN Environments

  • Jung, Young-Jin;Park, Chang Yun
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.10 no.8
    • /
    • pp.3753-3771
    • /
    • 2016
  • Increasingly, numerous and various Internet-capable devices are connected in end user networks, such as a home network. Most devices use the combination of TCP and 802.11 DCF as a system platform, but whereas some devices such as a streaming video persistently generate traffic, others such as a motion sensor do so only intermittently with lots of pauses. This study addresses the issue of performance in this heterogeneous traffic wireless LAN environment from the perspective of fairness. First, instantaneous fairness is introduced as a notion to indicate how immediately and how closely a user obtains its fair share, and a new time-based metric is defined as an index. Second, extensive simulation experiments have been made with TCP Reno, Vegas, and Westwood to determine how each TCP congestion control corresponds to the instantaneous fairness. Overall, TCP Vegas yields the best instantaneous fairness because it keeps the queue length shorter than the other TCPs. In the simulations, about 60% of a fair share of the effective user bandwidth is immediately usable in any circumstance. Finally, we introduce two simple strategies for adjusting TCP congestion controls to enhance instantaneous fairness and validate them through simulation experiments.

Power Allocation to Improve Data-Rate Fairness of Non-orthogonal Multiple Access Users (비직교 다중접속 사용자의 데이터 전송률 공정성 개선을 위한 전력 할당 기법)

  • Lee, In-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.23 no.9
    • /
    • pp.1117-1122
    • /
    • 2019
  • In this paper, a power allocation scheme is proposed to improve the fairness of user data rates in downlink non-orthogonal multiple access systems with one base station and two users. In particular, the power allocation scheme is presented to maximize the fairness of average user data rates assuming independent Rayleigh fading channels, where the fairness maximization is achieved when the average user data rates are equal. For the fairness evaluation, hence approximate expressions for the average user data rates and the average sum date rate of the proposed scheme are provided by using high signal-to-noise ratio approximation. Through simulation investigation, the derived approximate expressions for the average data rates are verified, and it is shown that the proposed scheme is superior to the conventional power allocation schemes in terms of the fairness of the average user data rates.

QoS-Guaranteed Multiuser Scheduling in MIMO Broadcast Channels

  • Lee, Seung-Hwan;Thompson, John S.;Kim, Jin-Up
    • ETRI Journal
    • /
    • v.31 no.5
    • /
    • pp.481-488
    • /
    • 2009
  • This paper proposes a new multiuser scheduling algorithm that can simultaneously support a variety of different quality-of-service (QoS) user groups while satisfying fairness among users in the same QoS group in MIMO broadcast channels. Toward this goal, the proposed algorithm consists of two parts: a QoS-aware fair (QF) scheduling within a QoS group and an antenna trade-off scheme between different QoS groups. The proposed QF scheduling algorithm finds a user set from a certain QoS group which can satisfy the fairness among users in terms of throughput or delay. The antenna trade-off scheme can minimize the QoS violations of a higher priority user group by trading off the number of transmit antennas allocated to different QoS groups. Numerical results demonstrate that the proposed QF scheduling method satisfies different types of fairness among users and can adjust the degree of fairness among them. The antenna trade-off scheme combined with QF scheduling can improve the probability of QoS-guaranteed transmission when supporting different QoS groups.

Two-Step Scheduling Scheme to Support Fairness and QoS in DVB-S2 System

  • Park, ManKyu;Kang, DongBae;Oh, DeockGil
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.9 no.11
    • /
    • pp.4419-4435
    • /
    • 2015
  • The use of an efficient packet scheduling scheme for a forward link in satellite communication networks is very important to support fairness for each return channel satellite terminal (RCST) and the service differentiations for user traffics. To support fairness and QoS for each RCST with service-level agreement (SLA), the Adaptive Coding and Modulation (ACM) system in a satellite hub has to process packets with considering modulation and coding (MODCOD) and packet types. Although a DVB-S2 system with ACM scheme has higher transmission efficiency, it cannot offer fairness or quality of service (QoS) to RCSTs. Because the data are transmitted with high MODCOD in regions with clear skies, while data are transmitted using low MODCOD in regions experiencing rain events. In this paper, we propose a two-step scheduling scheme offering fairness and QoS to RCSTs, while minimizing a decrease in throughput. The proposed scheme is carried out performance evaluations using a computer simulation. As results of this simulation, the proposed scheduler was shown to support bandwidth fairness to an individual RCST, and provide a level of QoS differentiation for user traffics.

Packet Scheduling for Cellular Relay Networks by Considering Relay Selection, Channel Quality, and Packet Utility

  • Zhou, Rui;Nguyen, Hoang Nam;Sasase, Iwao
    • Journal of Communications and Networks
    • /
    • v.11 no.5
    • /
    • pp.464-472
    • /
    • 2009
  • In this paper, we propose a packet scheduling algorithm for cellular relay networks by considering relay selection, variation of channel quality, and packet delay. In the networks, mobile users are equipped with not only cellular but also user relaying radio interfaces, where base station exploits adaptive high speed downlink channel. Our proposed algorithm selects a user with good cellular channel condition as a relay station for other users with bad cellular channel condition but can get access to relay link with good quality. This can achieve flexible packet scheduling by adjusting transmission rates of cellular link. Packets are scheduled for transmission depending on scheduling indexes which are calculated based on user's achieved transmission rate, packet utility, and proportional fairness of their throughput. The performance results obtained by using computer simulation show that the proposed scheduling algorithm is able to achieve high network capacity, low packet loss, and good fairness in terms of received throughput of mobile users.

Efficiency and Fairness in Information System Chargeback (정보시스템 Chargeback에 있어서의 효율성과 공평성의 관계)

  • Yu, Yeong-Jin;An, Jung-Ho
    • Asia pacific journal of information systems
    • /
    • v.1 no.1
    • /
    • pp.117-145
    • /
    • 1991
  • IS changeback is regarded as an offective way to control the usage of computers and communication systems which are very much limited resources and whose costs are very high, In this paper, the problem of combining the optimal chargeback system which guarantees the efficiency with the Rawls'(1971) concept of fairness. Primary conclusion of this paper is that if the value function which represents the contributions of IS user to the firm's profit is evidit and there is no uncertainty about this contribution information, optimality can be achived without any loss of fairness using full cost allocation pricing. But if there is no significant differences among contribution of each user and there is no significant differences among users because of the managerial arbitrariness, From this point of view contingent chargeback system with which manager can find the golden middle between optimality and fairness by adjusting the 'efficiency coefficient' according to his/her organizational characterisics and environments is proposed. A heuristic of finding the appropriate efficiency coefficient is also suggested.

  • PDF

On Power Calculation for First and Second Strong Channel Users in M-user NOMA System

  • Chung, Kyuhyuk
    • International journal of advanced smart convergence
    • /
    • v.9 no.3
    • /
    • pp.49-58
    • /
    • 2020
  • Non-orthogonal multiple access (NOMA) has been recognized as a significant technology in the fifth generation (5G) and beyond mobile communication, which encompasses the advanced smart convergence of the artificial intelligence (AI) and the internet of things (IoT). In NOMA, since the channel resources are shared by many users, it is essential to establish the user fairness. Such fairness is achieved by the power allocation among the users, and in turn, the less power is allocated to the stronger channel users. Especially, the first and second strong channel users have to share the extremely small amount of power. In this paper, we consider the power optimization for the two users with the small power. First, the closed-form expression for the power allocation is derived and then the results are validated by the numerical results. Furthermore, with the derived analytical expression, for the various channel environments, the optimal power allocation is investigated and the impact of the channel gain difference on the power allocation is analyzed.

Opportunistic Scheduling Schemes for Elastic Services in OFDMA Systems (OFDMA 시스템에서 Elastic 서비스를 위한 Opportunistic 스케줄링 기법)

  • Kwon, Jeong-Ahn;Lee, Jang-Won
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.34 no.1A
    • /
    • pp.76-83
    • /
    • 2009
  • In this paper, we provide opportunistic scheduling schemes for elastic services in OFDMA systems with fairness constraints for each user. We adopt the network utility maximization framework in which a utility function is defined for each user to represent its level of satisfaction to the service. Since we consider elastic services whose degree of satisfaction depends on its average data rate, we define the utility function of each user as a function of its average data rate. In addition, for fair resource allocation among users, we define fairness requirements of each user by using utility functions. We first formulate an optimization problem for each fairness requirement that aim at maximizing network utility, which is defined as the sum of utilities of users. We then develop an opportunistic scheduling scheme for each fairness requirement by solving the problem using a dual approach and a stochastic sub-gradient algorithm.

Analysis of The Mediating Effect of Food Quality and Price Fairness in The Relation between Servicescape and User Satisfaction - A Case Study of A University Student Cafeteria Evaluation - (서비스스케이프가 이용만족 간의 관계에서 음식의 품질과 가격공정성의 매개효과 분석 -A대학 학생 식당 사례를 중심으로-)

  • Kim, Jong-Moo
    • Journal of Digital Convergence
    • /
    • v.17 no.3
    • /
    • pp.379-387
    • /
    • 2019
  • This study analyzed what the Servicescape factor of the student cafeteria in university is, whether food quality and price fairness show any mediating effect in relation between Servicescape factor and user satisfaction. First, analysis shows that Servicescape factors of cafeteria for university students are 'extensity', 'cleanness', 'aesthetic' and 'agreeableness'. Second, 'cleanness and 'aesthetic' factors are found to have positive(+) influences on user satisfaction. Third, 'cleanness', 'aesthetic' factors are found to have positive(+) influences on food quality. Fourth, 'cleanness' factors of food quality shows complete mediating effect in the influential relation between Servicescape factor and user satisfaction and 'aesthetic' factors shows partial mediating effect. Fifth, significant influence was not seen in all factors of price fairness by Servicescape factors of student cafeteria in university. Sixth, price fairness was found to play no mediating role in the influential relation between Servicescape factor and user satisfaction. This study will help understand the mediating effect of food quality and price fairness in the relation between the Servicescape of student cafeteria in university and user satisfaction.