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222
A tutorial on crosslayer optimization in wireless networks
 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
, 2006
"... This tutorial paper overviews recent developments in optimization based approaches for resource allocation problems in wireless systems. We begin by overviewing important results in the area of opportunistic (channelaware) scheduling for cellular (singlehop) networks, where easily implementable my ..."
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Cited by 248 (29 self)
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This tutorial paper overviews recent developments in optimization based approaches for resource allocation problems in wireless systems. We begin by overviewing important results in the area of opportunistic (channelaware) scheduling for cellular (singlehop) networks, where easily implementable myopic policies are shown to optimize system performance. We then describe key lessons learned and the main obstacles in extending the work to general resource allocation problems for multihop wireless networks. Towards this end, we show that a cleanslate optimization based approach to the multihop resource allocation problem naturally results in a “loosely coupled” crosslayer solution. That is, the algorithms obtained map to different layers (transport, network, and MAC/PHY) of the protocol stack are coupled through a limited amount of information being passed back and forth. It turns out that the optimal scheduling component at the MAC layer is very complex and thus needs simpler (potentially imperfect) distributed solutions. We demonstrate how to use imperfect scheduling in the crosslayer framework and describe recently developed distributed algorithms along these lines. We conclude by describing a set of open research problems.
Fair Resource Allocation in Wireless Networks using Queuelengthbased Scheduling and Congestion Control
"... We consider the problem of allocating resources (time slots, frequency, power, etc.) at a base station to many competing flows, where each flow is intended for a different receiver. The channel conditions may be timevarying and different for different receivers. It is wellknown that appropriate ..."
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Cited by 202 (45 self)
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We consider the problem of allocating resources (time slots, frequency, power, etc.) at a base station to many competing flows, where each flow is intended for a different receiver. The channel conditions may be timevarying and different for different receivers. It is wellknown that appropriately chosen queuelength based policies are throughputoptimal while other policies based on the estimation of channel statistics can be used to allocate resources fairly (such as proportional fairness) among competing users. In this paper, we show that a combination of queuelengthbased scheduling at the base station and congestion control implemented either at the base station or at the end users can lead to fair resource allocation and queuelength stability.
A framework for opportunistic scheduling in wireless networks,”
 Computer Networks,
, 2003
"... AbstractScheduling has been extensively studied in various disciplines in operations research and wireline networking. However, the unique characteristics of wireless communication systems namely, timingvarying channel conditions and multiuser diversity means that new scheduling solutions need ..."
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Cited by 167 (8 self)
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AbstractScheduling has been extensively studied in various disciplines in operations research and wireline networking. However, the unique characteristics of wireless communication systems namely, timingvarying channel conditions and multiuser diversity means that new scheduling solutions need to be developed that are specifically tailored for this environment. In this paper, we summarize various opportunistic scheduling schemes that exploit the timevarying nature of the radio environment to improve the spectrum efficiency while maintaining a certain level of satisfaction for each user. We also discuss the advantages and costs associated with opportunistic scheduling, and identify possible future research directions.
Stable scheduling policies for fading wireless channels
 IEEE/ACM Trans. Networking
, 2005
"... We study the problem of stable scheduling for a class of wireless networks. The goal is to stabilize the queues holding information to be transmitted over a fading channel. Few assumptions are made on the arrival process statistics other than the assumption that their mean values lie within the capa ..."
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Cited by 136 (39 self)
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We study the problem of stable scheduling for a class of wireless networks. The goal is to stabilize the queues holding information to be transmitted over a fading channel. Few assumptions are made on the arrival process statistics other than the assumption that their mean values lie within the capacity region and that they satisfy a version of the law of large numbers. We prove that, for any mean arrival rate that lies in the capacity region, the queues will be stable under our policy. Moreover, we show that it is easy to incorporate imperfect queue length information and other approximations that can simplify the implementation of our policy. 1
On the Asymptotic Optimality of the Gradient Scheduling Algorithm for MultiUser Throughput Allocation
 Operations Research
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Exploiting multiuser diversity for medium access control in wireless networks
 Proc. of IEEE INFOCOM
, 2003
"... Abstract Multiuser diversity refers to a type of diversity present across different users in a fading environment. This diversity can be exploited by scheduling transmissions so that users transmit when their channel conditions are favorable. Using such an approach leads to a system capacity that ..."
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Cited by 98 (5 self)
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Abstract Multiuser diversity refers to a type of diversity present across different users in a fading environment. This diversity can be exploited by scheduling transmissions so that users transmit when their channel conditions are favorable. Using such an approach leads to a system capacity that increases with the number of users. However, such scheduling requires centralized control. In this paper, we consider a decentralized medium access control (MAC) protocol, where each user only has knowledge of its own channel gain. We consider a variation of the ALOHA protocol, channelaware ALOHA; using this protocol we show that users can still exploit multiuser diversity gains. First we consider a backlogged model, where each user always has packets to send. In this case we show that the total system throughput increases at the same rate as in a system with a centralized scheduler. Asymptotically, the fraction of throughput lost due to the random access protocol is shown to be 1=e. We also consider a splitting algorithm, where the splitting sequence depends on the users ' channel gains; this algorithm is shown to approach the throughput of an optimal centralized scheme. Next we consider a system with an infinite user population and random arrivals. In this case, it is proved that a variation of channelaware ALOHA is stable for any total arrival rate in a memoryless channel, given that users can estimate the backlog. Extensions for channels with memory are also discussed. I.
Opportunistic Splitting Algorithms For Wireless Networks
, 2004
"... In this paper, we develop medium access control protocols to enable users in a wireless network to opportunistically transmit when they have favorable channel conditions, without requiring a centralized scheduler. We consider approaches that use splitting algorithms to resolve collisions over a sequ ..."
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Cited by 88 (2 self)
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In this paper, we develop medium access control protocols to enable users in a wireless network to opportunistically transmit when they have favorable channel conditions, without requiring a centralized scheduler. We consider approaches that use splitting algorithms to resolve collisions over a sequence of minislots, and determine the user with the best channel. First, we present a basic algorithm for a system with i.i.d. block fading and a fixed number of backlogged users. We give an analysis of the throughput of this system and show that the average number of minislots required to find the user with the best channel is less than 2.5 independent of the number of users or the fading distribution. We then extend this algorithm to a channel with memory and also develop a reservation based scheme that offers improved performance as the channel memory increases. Finally we consider a model with random arrivals and propose a modified algorithm for this case. Simulation results are given to illustrate the performance in each of these settings.
Distributed Learning in MultiArmed Bandit with Multiple Players
 IEEE TRANSACTIONS ON SIGNAL PROCESSING
, 2010
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CellThroughput Analysis of the Proportional Fair Scheduler in the SingleCell Environment
 IEEE Trans. Veh. Technol
, 2007
"... Abstract. The fairness concept has been widely studied in the area of data networks. The most wellknown fairness criterion, maxmin fairness, gives priority to the minimum rate session. Kelly questioned its appropriateness in his works on the bandwidth sharing among the endtoend flows and propos ..."
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Cited by 63 (6 self)
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Abstract. The fairness concept has been widely studied in the area of data networks. The most wellknown fairness criterion, maxmin fairness, gives priority to the minimum rate session. Kelly questioned its appropriateness in his works on the bandwidth sharing among the endtoend flows and proposed another fairness criterion preferring short distance flows to enhance the overall throughput, which is called the proportional fairness (PF). A simple scheduler achieving this objective was introduced in wireless access networks and revealed that it can achieve a good compromise between cell throughput and user fairness. Though it has received much attention for some time, research on its performance mainly depended on computer simulations. In this paper, we analyze the PF scheduler to obtain the cell throughput which is a primary performance metric.
Optimal utility based multiuser throughput allocation subject to throughput constraints
 in Proc. IEEE INFOCOM
, 2005
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