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| 2. |
- Soldati, Pablo, et al.
(författare)
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Distributed optimization of end-to-end rates and radio resources in WiMax single-carrier networks
- 2006
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Ingår i: GLOBECOM - IEEE Global Telecommunications Conference. - 9781424403561
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of joint end-to-end band-width allocation and radio resource management in WiMax single-carrier wireless networks. The design problem is posed as a utility maximization problem subject to link rate constraints which involve transmission scheduling and power allocation. Inspired by a centralized algorithm for solving the associated optimization problem, we proceed systematically in our development of distributed resource allocation mechanisms. Contrary to the centralized algorithm, the proposed solution is distributed and of low computational complexity, generates schedules of finite length and with fixed time-slot durations, and acts on local neighborhood information only. Although the final scheme is suboptimal, we isolate and quantify the performance losses incurred and demonstrate strong performance in examples.
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| 3. |
- Soldati, Pablo, et al.
(författare)
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Proportionally fair allocation of end-to-end bandwidth in STDMA wireless networks
- 2006
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Ingår i: Proceedings of the International Symposium on Mobile Ad Hoc Networking and Computing. - New York, NY, USA : ACM. - 9781595933683 ; , s. 286-297
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of designing distributed mechanisms for joint congestion control and resource allocation in spatial-reuse TDMA wireless networks. The design problem is posed as a utility maximization subject to link rate constraints that involve both power allocation and transmission scheduling over multiple time-slots. Starting from the performance limits of a centralized optimization based on global network information, we proceed systematically in the development of distributed and transparent protocols. In the process, we introduce a novel decomposition method for convex optimization, establish its convergence for the utility maximization problem and demonstrate how it suggests a distributed solution based on flow control optimization and incremental updates of the transmission schedule. We develop a two-step procedure for finding the schedule updates and suggest two schemes for distributed channel reservation and power control under realistic interference models. Although the final protocols are suboptimal, we isolate and quantify the performance losses incurred by each simplification and demonstrate strong performance in examples.
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| 4. |
- António, Gonga, et al.
(författare)
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Multi-channel communication vs. adaptive routing for reliable communication in WSNs
- 2012
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Ingår i: IPSN'12 - ACM/IEEE Proceedings of the 11th International Conference on Information Processing in Sensor Networks, (Beijing;16 - 20 April 2012). - New York, NY, USA : ACM. - 9781450312271 ; , s. 125-126
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Konferensbidrag (refereegranskat)abstract
- Interference and link dynamics constitute great concerns for stability and performance of protocols in WSNs. In this paper we evaluate the impact of channel hopping and adaptive routing on delay and reliability focusing on delay critical applications.
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| 5. |
- Belleschi, Marco, et al.
(författare)
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Fast power control for cross-layer optimal resource allocation in DS-CDMA wireless networks
- 2009
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Ingår i: 2009 IEEE International Conference on Communications. ; , s. 4341-4346
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Konferensbidrag (refereegranskat)abstract
- This paper presents a novel cross-layer design for joint power and end-to-end rate control optimization in DS-CDMA wireless networks, along with a detailed implementation and evaluation in the network simulator ns-2. Starting with a network utility maximization formulation of the problem, we derive distributed power control, transport rate and queue management schemes that jointly achieve the optimal network operation. Our solution has several attractive features compared to alternatives: it adheres to the natural time-scale separation between rapid power control updates and slower end-to-end rate adjustments, and uses simplified power control mechanisms with reduced signalling requirements. We argue that these features are critical for a successful real-world implementation. To validate these claims, we present a detailed implementation of a crosslayer adapted networking stack for DS-CSMA ad-hoc networks in ns-2. We describe several critical issues that arise in the implementation, but are typically neglected in the theoretical protocol design, and evaluate the alternatives in extensive simulations.
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| 6. |
- Demirel, Burak, et al.
(författare)
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Modular Co-Design of Controllers and Transmission Schedules in WirelessHART
- 2011
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Ingår i: IEEE Conference on Decision and Control. ; , s. 5951-5958
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Konferensbidrag (refereegranskat)abstract
- We consider the joint design of transmissionschedules and controllers for networked control loops that useWirelessHART communication for sensor and actuator data. Byparameterizing the design problem in terms of the samplingrate of the control loop, the co-design problem separates intotwo well-defined subproblems which admit optimal solutions:transmission scheduling should be done to maximize the delayconstrained reliability while the control design should optimizeclosed-loop performance under packet loss. We illustrate howthese problems can be solved and demonstrate our co-designframework for the case of linear-quadratic contro
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| 7. |
- Demirel, Burak, et al.
(författare)
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Modular Design of Jointly Optimal Controllers and Forwarding Policies for Wireless Control
- 2014
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Ingår i: IEEE Transactions on Automatic Control. - 0018-9286 .- 1558-2523. ; 59:12, s. 3252-3265
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Tidskriftsartikel (refereegranskat)abstract
- We consider the joint design of packet forwarding policies and controllers for wireless control loops where sensor measurements are sent to the controller over an unreliable and energy-constrained multi-hop wireless network. For fixed sampling rate of the sensor, the co-design problem separates into two well-defined and independent subproblems: transmission scheduling for maximizing the deadline-constrained reliability and optimal control under packet loss. We develop optimal and implementable solutions for these subproblems and show that the optimally co-designed system can be efficiently found. Numerical examples highlight the many trade-offs involved and demonstrate the power of our approach.
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| 8. |
- Fodor, Gabor, et al.
(författare)
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Near optimum power control and precoding under fairness constraints in network MIMO systems
- 2009
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Ingår i: International Journal of Digital Multimedia Broadcasting. - : Hindawi Limited. - 1687-7578 .- 1687-7586. ; 2010, s. 251719-
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Tidskriftsartikel (refereegranskat)abstract
- We consider the problem of setting the uplink signal-to-noise-and- interference (SINR) target and allocating transmit powers for mobile stations in multicell spatial multiplexing wireless systems. Our aim is twofold: to evaluate the potential of such mechanisms in network multiple input multiple output (MIMO) systems, and to develop scalable numerical schemes that allow real-time near-optimal resource allocation across multiple sites. We formulate two versions of the SINR target and power allocation problem: one for maximizing the sum rate subject to power constraints, and one for minimizing the total power needed to meet a sum-rate target. To evaluate the potential of our approach, we perform a semianalytical study in Mathematica using the augmented Lagrangian penalty function method. We find that the gain of the joint optimum SINR setting and power allocation may be significant depending on the degree of fairness that we impose. We develop a numerical technique, based on successive convexification, for real-time optimization of SINR targets and transmit powers. We benchmark our procedure against the globally optimal solution and demonstrate consistently strong performance in realistic network MIMO scenarios. Finally, we study the impact of near optimal precoding in a multicell MIMO environment and find that precoding helps to reduce the sum transmit power while meeting a capacity target.
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| 9. |
- Fodor, Gabor, et al.
(författare)
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Near Optimum Power Control Under Fairness Constraints in CoMP Systems
- 2009
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Ingår i: GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE. - 9781424441471 ; , s. 5274-5281
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of setting the uplink signal-to-noise-and-interference (SINR) target and allocating transmit powers for mobile stations in multicell spatial multiplexing wireless systems. Our aim is twofold: to evaluate the potential of such mechanisms in coordinated multipoint transmission (CoMP) systems, and to develop scalable numerical schemes that allow real-time near-optimal resource allocation across multiple sites. We formulate two versions of the SINR target and power allocation problem: one for maximizing the sum rate subject to power constraints, and one for minimizing the total power needed to meet a sum-rate target. To evaluate the potential of our approach, we perform a semi-analytical study in Mathematica using the augmented Lagrangian penalty function method. We find that the gain of the joint optimum SINR setting and power allocation may be significant depending on the degree of fairness that we impose. We develop a numerical technique, based on successive convexification, for real-time optimization of SINR targets and transmit powers. We benchmark our procedure against the globally optimal solution, and demonstrate consistently strong performance in realistic CoMP scenarios.
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| 10. |
- Fodor, Gabor, et al.
(författare)
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On the impact of uplink power control in network MIMO systems with MMSE and SIC receivers
- 2010
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Ingår i: 2010 IEEE International Symposium on 'A World of Wireless, Mobile and Multimedia Networks'. - 9781424472659
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Konferensbidrag (refereegranskat)abstract
- Network multiple input, multiple output (MIMO) systems are built around a broadband backbone network that allows for the fast communication of channel state information (CSI) as well as user data between different base stations. Previous works have shown that multicell channel adaptive (opportunistic) power control can minimize the sum power or maximize the sum rate when the backbone is used for the exchange of CSI in network MIMO systems. In this work we investigate the gains of multicell opportunistic power control under per user fairness constraints when both CSI and user data are shared between multiple sites. We find that multicell opportunistic power control working in concert with uplink joint signal detection is an efficient means both for the capacity and the power control problems that not only minimizes sum power or maximizes overall capacity, but is also able to provide arbitrary level of fairness.
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