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On the Starvation Period of CDF-Based Scheduling over Markov Time-Varying Channels
Yoora Kim 한국통신학회 2016 韓國通信學會論文誌 Vol.26 No.12
In this paper, we consider a cumulative distribution function (CDF)-based opportunistic scheduling for downlink transmission in a cellular network consisting of a base station and multiple mobile stations. We present a closed-form formula for the average starvation period of each mobile station (i.e., the length of the time interval between two successive scheduling points of a mobile station) over Markov time-varying channels. Based on our formula, we investigate the starvation period of the CDF-based scheduling for various system parameters.
Threshold-based opportunistic scheduling for ergodic rate guarantees in wireless networks
Yoora Kim,Gang Uk Hwang IEEE 2009 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.8 No.1
<P>In this paper, we propose an opportunistic downlink scheduling scheme that exploits multiuser diversity in a wireless network with threshold-based limited feedback. We assume that each user has its own ergodic rate requirement. The design objective of our scheme is to determine the values of thresholds with which heterogeneous ergodic rate requirements of all users are satisfied. In our analysis, we present a formula to check the feasibility of given ergodic rate requirements, and then obtain the feasible thresholds that realize them. We also obtain the optimal thresholds that maximize the ergodic sum-rate of the network while guaranteeing the ergodic rate requirements. Through numerical studies and simulations, we show the usefulness of our scheme and analysis.</P>
LONG-TERM THROUGHPUT GUARANTEES BY OPPORTUNISTIC SCHEDULING WITH LIMITED FEEDBACK
Yoora KIM,Gang Uk HWANG 한국산업응용수학회 2008 한국산업응용수학회 학술대회 논문집 Vol.4 No.3
In this paper, we consider a wireless network consisting of a base station (BS) and multiple mobile stations (MSs). We propose an opportunistic scheduling scheme that aims at guaranteeing long-term throughputs by exploiting multiuser diversity with limited feedback.
Yoora Kim,Gang Uk Hwang IEEE 2008 IEEE Transactions on Vehicular Technology VT Vol.57 No.5
<P>In this paper, we consider an M-ary quadrature amplitude modulation (M-QAM) scheme combined with multiuser diversity over Nakagami-<I>m</I> fading channels. Assuming that delayed but error-free signal-to-noise ratio (SNR) feedback is available, we derive closed-form formulas for the average transmission rate and the average bit error rate (BER), which are also shown to be generalizations of many previous results. Through numerical studies and simulations, we check the validity of our analysis. In addition, we investigate the impact of the Nakagami fading parameter <I>m</I> and feedback delay on system performance.</P>
Capacity Analysis of Opportunistic Scheduling in Nakagami- <tex> $m$</tex> Fading Environments
Yoora Kim,Sungoh Kwon IEEE 2015 IEEE Transactions on Vehicular Technology VT Vol.64 No.11
<P>The wireless medium has a time-varying feature due to fading, and individual users experience different degrees of fading. Opportunistic scheduling exploits such diversity of fading across users to improve network performance. In this paper, we explicitly analyze the capacity of opportunistic scheduling in various fading environments. To that end, we use Nakagami-m fading as a fading channel model and analyze the multiuser diversity capacity when considering the number of users and fading parameters. Our analysis shows that the mean capacity is explicitly decomposed into three factors: the average signal-to-noise ratio (SNR), the number of users, and the capacity improvement that comes from diversity of fading across users. Our analytical results provide the precise impact of fading channels on multiuser capacity, which asymptotic analysis cannot capture. We verify the analytical results via simulations.</P>
Queueing Performance Analysis of CDF-Based Scheduling over Markov Fading Channels
Yoora Kim 한국통신학회 2016 韓國通信學會論文誌 Vol.28 No.8A
In this paper, we analyze the queueing performance of cumulative distribution function (CDF)-based opportunistic scheduling over Nakagami-m Markov fading channels. We derive the formula for the average queueing delay and the queue length distribution by constructing a two-dimensional Markov chain. Using our formula, we investigate the queueing performance for various fading parameters.
QUEUEING ANALYSIS OF OPPORTUNISTIC SCHEDULE EXPLOITING MULTIUSER DIVERSITY
Yoora KIM,Gang Uk HWANG 한국산업응용수학회 2007 한국산업응용수학회 학술대회 논문집 Vol.2 No.1
In this paper, we consider a wireless communication network with multiple users where an opportunistic scheduler exploiting multiuser diversity is employed. We focus on the joint effect of the queue state at the data link layer and the channel state at the physical layer on the performance of the opportunistic scheduler. Accordingly, we model the arrival process, the service process and the queue state recursion. We then develop a two dimensional Markov chain containing the queue state as well as the channel state. From the stationary and limiting distributions of the Markov chain, we derive QoS measures such as throughput, average queue length, blocking probability and average queueing delay.
CROSS-LAYER DESIGN OF OPPORTUNISTIC SCHEDULING FOR WIRELESS NETWORKS WITH FINITE BACKLOG
Yoora KIM,Gang Uk HWANG 한국산업응용수학회 2007 한국산업응용수학회 학술대회 논문집 Vol.3 No.2
In this talk, we propose a new cross-layer opportunistic scheduling (OS) scheme exploiting multiuser diversity for wireless networks with finite backlog. Accordingly, we consider the joint effect of the queueing at the data link layer and the channel state at the physical layer of the network. Through simulations, we examine the usefulness and the characteristics of our queue length aware OS scheme.