| 1. |
- 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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| 2. |
- 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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| 3. |
- Soldati, Pablo, et al.
(författare)
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Optimal Routing and Scheduling of Deadline-Constrained Traffic Over Lossy Networks
- 2010
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Ingår i: 2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010. - 9781424456383
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Konferensbidrag (refereegranskat)abstract
- The traditionally wired automation infrastructure is quickly migrating to more flexible and scalable wireless solutions. To cope with the stringent requirements of process automation in terms of latency and reliability, the network resources must be optimized to ensure timely and reliable communication. This paper considers the joint routing and transmission scheduling problem for reliable real-time communication over lossy networks. Specifically, we impose a strict latency bound for packet delivery from source to destination, and devise optimal transmission scheduling policies that maximize the success probability of delivering the packet within the specified deadline. A solution to this problem allows to characterize the set of achievable latencies and packet reliability for a given network. We offer a complete understanding of the problem when erasure events on links are independent and follow a Bernoulli process. We consider both static and dynamic resource allocation policies, and compare them in numerical examples.
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| 4. |
- Steinmetz, Erik, et al.
(författare)
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Collision-Aware Communication for Intersection Management of Automated Vehicles
- 2018
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Ingår i: IEEE Access. - 2169-3536. ; 6, s. 77359-77371
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Tidskriftsartikel (refereegranskat)abstract
- Intersection management of automated vehicles relies on wireless communication, whereby communication resources should be allocated to vehicles while maintaining safety. We present a collision-aware resource allocation (CARA) strategy for coordination of automated and connected vehicles by a centralized intersection manager. The proposed strategy is based on a self-triggered approach and proactively reduces the risk of channel congestion by only assigning communication resources to vehicles that are in critical configurations, i.e., when there is a risk for a future collision. Compared with collision-agnostic communication strategies, typically considered for automated intersection management, the CARA strategy aims to bridge the gap between control, sensing, and communication. It is shown to significantly reduce the required amount of communication (albeit with a slight increase in the control cost), without compromising safety. Furthermore, control cost can be reduced by allowing more frequent communication, which we demonstrate through a trade-off analysis between control performance and communication load. Hence, CARA can operate in communication-limited scenarios, but also be modified for scenarios where the control cost is of primary interest.
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| 5. |
- Talebi Mazraeh Shahi, Mohammad Sadegh, 1982-, et al.
(författare)
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Stochastic Online Shortest Path Routing : The Value of Feedback
- 2018
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Ingår i: IEEE Transactions on Automatic Control. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9286 .- 1558-2523. ; 63:4, s. 915-930
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Tidskriftsartikel (refereegranskat)abstract
- This paper studies online shortest path routing over multihop networks. Link costs or delays are time varying and modeled by independent and identically distributed random processes, whose parameters are initially unknown. The parameters, and hence the optimal path, can only be estimated by routing packets through the network and observing the realized delays. Our aim is to find a routing policy that minimizes the regret (the cumulative difference of expected delay) between the path chosen by the policy and the unknown optimal path. We formulate the problem as a combinatorial bandit optimization problem and consider several scenarios that differ in where routing decisions are made and in the information available when making the decisions. For each scenario, we derive a tight asymptotic lower bound on the regret that has to be satisfied by any online routing policy. Three algorithms, with a tradeoff between computational complexity and performance, are proposed. The regret upper bounds of these algorithms improve over those of the existing algorithms. We also assess numerically the performance of the proposed algorithms and compare it to that of existing algorithms.
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| 6. |
- Zou, Zhenhua, et al.
(författare)
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Deadline-constrained maximum reliability packet forwarding with limited channel state information
- 2013
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Ingår i: 2013 IEEE Wireless Communications and Networking Conference (WCNC). - New York : IEEE Communications Society. - 9781467359399 ; , s. 1721-1726
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Konferensbidrag (refereegranskat)abstract
- This paper considers real-time packet forwarding over wireless multi-hop networks with lossy and bursty links. Our objective is to maximize the probability that individual packets reach their destination before a hard deadline. The loss processes on links are modeled by finite-state Markov chains. While the parameters of the Markov chains are assumed to be known, the instantaneous channel states are not accessible but have to be estimated from observations of successes and failures of actual packet transmissions. We formulate the forwarding problem as a partially observable Markov decision process and derive the optimal forwarding policy. A novel technique, based on maximum-volume inscribed ellipsoids, for computing approximate solutions with reduced implementation complexity is proposed. We further discuss structural properties of the value function and the optimal actions. Finally, numerical examples illustrate the power of the developed techniques.
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| 7. |
- Zou, Zhenhua, et al.
(författare)
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Delay-constrained maximum reliability routing over lossy links
- 2010
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Ingår i: Proceedings of the IEEE Conference on Decision and Control. - : IEEE. - 9781424477456 ; , s. 973-978
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Konferensbidrag (refereegranskat)abstract
- This paper studies the problem of joint routing and transmission scheduling for reliable real-time communication over lossy networks. We impose a strict latency bound on the packet delivery from source to destination and develop transmission scheduling policies that maximize the probability that the packet is delivered within the specified deadline. A solution to this problem allows to characterize the set of achievable latencies and packet loss probabilities for a given network. We develop dynamic programming-based solutions for deadline-constrained maximum reliability routing under Bernoulli and Gilbert-Elliot packet loss models. Particular instances of the problem that admit numerically efficient solutions are discussed and our results are demonstrated on several examples.
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| 8. |
- Zou, Zhenhua, et al.
(författare)
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Energy-efficient deadline-constrained maximum reliability forwarding in lossy networks
- 2012
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Ingår i: IEEE Transactions on Wireless Communications. - 1536-1276 .- 1558-2248. ; 11:10, s. 3474-3483
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Tidskriftsartikel (refereegranskat)abstract
- This paper studies the problem of optimal forwarding for reliable and energy-efficient real-time communication over multi-hop wireless lossy networks. We impose a strict per-packet latency bound and develop forwarding policies that maximize the probability that the packet is delivered within the specified deadline minus a transmission energy cost. A solution to this problem allows to characterize the set of achievable latency-reliability pairs and to trace out the Pareto frontier between achievable deadline-constrained reliability and transmission energy cost. We develop dynamic programming-based solutions under a finite-state Markov channel model. Particular instances with Bernoulli and Gilbert-Elliot loss models that admit numerically efficient solutions are discussed and our results are demonstrated on several examples.
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| 9. |
- Zou, Zhenhua, et al.
(författare)
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Minimum-energy packet forwarding over lossy networks under deadline and reliability constraints
- 2012
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Ingår i: 10th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt),2012. - : IEEE conference proceedings. - 9783901882470 ; , s. 224-231
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Konferensbidrag (refereegranskat)abstract
- This paper studies minimum-energy packet forwardingover multi-hop lossy networks under deadline andreliability constraints. We assume a routing topology in theform of a directed graph with packet loss processes on linksdescribed by finite-state Markov chains, and formulate the forwardingproblem as a finite-horizon constrained Markov decisionprocess. We show that the minimum energy forwarding policyunder hard deadline and reliability constraint can be computedusing dynamic programming, and that the optimal forwardingpolicy is a randomized policy over two history-independent anddeterministic policies. Closed-form optimal policies are derivedfor some particular scenarios. Numerical examples show thatthe transmission energy cost of achieving reliabilities close to themaximum can be significant when links are bursty. In addition,transmission power adjustments can further reduce energy cost.Finally, we develop simple heuristic policies with a good balancebetween transmission energy cost and reliability.
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| 10. |
- Zou, Zhenhua, et al.
(författare)
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Minimum-energy packet forwarding policies for guaranteed LQG performance in wireless control systems
- 2012
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Ingår i: 2012 IEEE 51st Annual Conference on Decision and Control (CDC). - : IEEE. - 9781467320665 ; , s. 3341-3346
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Konferensbidrag (refereegranskat)abstract
- This paper studies minimum-energy packet forwarding policies for communicating sensor measurements from plant to controller over an unreliable multi-hop wireless network so as to guarantee that the optimal controller achieves a prespecified closed-loop performance. For fixed sampling interval, we demonstrate that the minimal linear-quadratic control loss is monotonically decreasing in the reliability of the sensor-to-controller communication. This allows us to decompose the overall design problem into two separate tasks: finding the minimum end-to-end reliability that allows to achieve a prespecified linear-quadratic loss, and developing minimum-energy packet forwarding policies under a deadline-constrained reliability requirement. We develop optimal solutions for both subproblems and show how the co-designed system with minimum forwarding energy cost and guaranteed LQG control performance can be found by a one-dimensional search over admissible sampling periods. The paper ends with a numerical example which demonstrates the effectiveness of the proposed framework.
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