&lt;title&gt;Class and channel condition-based scheduler for EDGE/GPRS&lt;/title&gt;

Agrawal, Rajeev; Bedekar, Anand; La, Richard J.; Pazhyannur, Rajesh; Subramanian, Vijay

doi:10.1117/12.434467

Cited by 13 publications

(8 citation statements)

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“…b 2 where g RR is the RR solution for current TTI. It is possible to initialise more individuals to other possible deterministic solutions such as proportional fair (PF) algorithm [13,14]. PF provides a better fairness than Max C/I scheduler and better throughput than RR.…”

Section: Initialisationmentioning

confidence: 99%

A genetic approach for downlink packet scheduling in HSDPA system

Abedi

Vadgama

2004

Soft Comput

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High speed downlink packet access (HSDPA) system currently under development in 3rd generation partnership project (3GPP) [1] employs number of parallel shared channels and adaptive modulation and coding scheme (MCS) to enable a high rate packet data transfer from base station (Node-B) to user equipment (UE). To decide how to share the available radio channel capacity amongst the active UEs, a packet scheduling and channel assignment algorithms are employed at Node B. Packet scheduling techniques such as max carrier to interference ratio (C/I) or round robin (RR) fails to take into account all the aspects of the quality of service (QoS) provisioning. In this paper, the fundamentals genetic algorithms and conventional wireless scheduling techniques are combined and the weaknesses of the existing known techniques are exploited to propose a novel hybrid genetic packet scheduler (HGPS) for the HSDPA system. A combination of random and intelligent diversity of population and comparative nature of the selection process of genetic engine contribute to its robustness. The proposed HGPS outperforms Max C/I packet scheduler in terms of total delivered throughput within low delay thresholds. Unlike conventional packet scheduling technique HGPS does not rely only on the current or past status of the scheduling process. By treating the possible solutions as points in a search space, the proposed HGPS through a genetically guided search visits and examines the possible solutions and estimates the impact of each these solution on overall performance of system in terms of fairness, throughput or QoS without actually performing a transmission. Subsequently, the solution that achieves the best estimated overall performance is chosen for the actual transmission. By means of computer simulation, performance of the HGPS algorithm is characterized in Rayleigh fading and shadowing radio channel conditions. The impact of imperfect reporting on the performance of HSDPA system is evaluated. We examine the joint impact of reporting latency, imperfect channel estimation and the corruption of reports in the feedback channel on the performance. It is shown that the proposed class of intelligent parallel random schedulers is highly robust against the imperfect reports from UEs.

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Section: Initialisationmentioning

confidence: 99%

A genetic approach for downlink packet scheduling in HSDPA system

Abedi

Vadgama

2004

Soft Comput

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“…Channel aware opportunistic scheduling was first developed for the downlink transmissions in multiuser wireless networks (see, e.g., [2], [5], [9], [16], [17], [25], [27]). Opportunistic scheduling originates from a holistic view: roughly speaking, in a multiuser wireless network, at each moment it is likely that there exists a user with good channel conditions; and by picking the instantaneous "on-peak" user for data transmission, opportunistic scheduling can utilize the wireless resource more efficiently.…”

Section: Motivationmentioning

confidence: 99%

“…As noted above, there has been much work on centralized opportunistic scheduling (e.g., [2], [5], [9], [16], [17], [25], [27]), channel-aware Aloha (e.g., [1,20]) and MAC design with rate adaptation (e.g., [14,19,23]). Most relevant to our study are perhaps (e.g., [1,14,20,23]).…”

Section: Related Work and Organizationmentioning

confidence: 99%

Distributed opportunistic scheduling for ad-hoc communications

Dong

Zhang

2007

Proceedings of the 8th ACM International Symposium on Mobile Ad Hoc Networking and Computing

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We consider distributed opportunistic scheduling (DOS) in wireless ad-hoc networks, where many links contend for the same channel using random access. In such networks, distributed opportunistic scheduling involves a process of joint channel probing and distributed scheduling. Due to channel fading, the link condition corresponding to a successful channel probing could be either good or poor. In the latter case, further channel probing, although at the cost of additional delay, may lead to better channel conditions and hence higher transmission rates. The desired tradeoff boils down to judiciously choosing the optimal stopping strategy for channel probing and the rate threshold. In this paper, we pursue a rigorous characterization of the optimal strategies from two perspectives, namely, a network-centric perspective and a user-centric perspective.We first consider DOS from a network-centric point of view, where links cooperate to maximize the overall network throughput. Using optimal stopping theory, we show that the optimal strategy turns out to be a pure threshold policy, where the rate threshold can be obtained by solving a fixed point equation. We further devise an iterative algorithm for computing the threshold.Next, we explore DOS from a user-centric perspective, where each links seeks to maximize its own throughput. We treat the problem of rate threshold selections for different links as a non-cooperative game. We explore the existence and uniqueness of the Nash equilibrium, and show that the Nash equilibrium can be approached by the best response strategy. We then develop an online stochastic iterative algorithm using local observations only, and establish its convergence. Finally, we observe that there is an efficiency loss in terms of the throughput at the Nash equilibrium, and introduce a pricing-based mechanism to mitigate the loss. *

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“…Channel aware opportunistic scheduling was first developed for the downlink transmissions in cellular wireless networks (see, e.g., [2], [4], [6], [7], [16], [17], [20], [21], [22]), assuming that the scheduler has knowledge of the instantaneous channel conditions for all links. That is to say, the scheduling is centralized.…”

Section: Introductionmentioning

confidence: 99%

Channel Aware Distributed Scheduling for Exploiting Multi-Receiver Diversity and Multiuser Diversity in Ad-Hoc Networks: A Unified PHY/MAC Approach

Cao

Zhang

2008

2008 Proceedings IEEE INFOCOM - The 27th Conference on Computer Communications

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We study channel aware distributed scheduling in ad hoc networks where many links contend for the common channel using random access, and the focus here is on the model where each transmitter node has multiple intended receivers. In such a network, channel probing takes place in two phases: 1) in phase I, all transmitters contend for the channel using random access to reserve the channel, and the probing to accomplish a successful channel contention takes a random duration; and 2) in phase II, subsequent probings are carried out to estimate the link conditions from the successful transmitter in phase I to its intended receivers, according to specific probing mechanisms, and the probing for each receiver takes a constant duration. In this paper, we shall study various probing mechanisms for utilizing multi-receiver diversity in phase II and multiuser diversity in phase I for ad hoc (peer-to-peer) communications.Clearly, further probing increases the likelihood of seeing better channel conditions for exploiting diversities, but at the cost of additional time. Therefore, channel probing must be done efficiently to balance the tradeoff between the throughput gain from better channel conditions and the probing cost. One main objective of this study is to characterize this tradeoff in a stochastic decision making framework. Specifically, we cast network throughput optimization as an optimal stopping problem, and then explore channel aware distributed scheduling to leverage multi-receiver diversity and multiuser diversity in a joint manner. We show that the optimal scheduling policies for all proposed probing mechanisms exhibit threshold structures, indicating that they are amenable to easy distributed implementation. We show that the optimal thresholds and the maximum network throughput can be obtained off-line by solving fixed point equations. We further develop iterative algorithms to compute the optimal thresholds and the throughput.

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<title>Class and channel condition-based scheduler for EDGE/GPRS</title>

Cited by 13 publications

References 10 publications

A genetic approach for downlink packet scheduling in HSDPA system

A genetic approach for downlink packet scheduling in HSDPA system

Distributed opportunistic scheduling for ad-hoc communications

Channel Aware Distributed Scheduling for Exploiting Multi-Receiver Diversity and Multiuser Diversity in Ad-Hoc Networks: A Unified PHY/MAC Approach

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