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Hoang, Le-Nam
Publications (9 of 9) Show all publications
Hoang, L.-N., Uhlemann, E. & Jonsson, M. (2017). A novel relaying scheme to guarantee timeliness and reliability in wireless networks. In: 2016 IEEE Globecom Workshops (GC Wkshps): Proceedings. Paper presented at IEEE Globecom 2016 – 3rd International Workshop on Ultra-Reliable and Low-Latency Communications in Wireless Networks (URLLC), Washington, DC, USA, Dec. 8, 2016. New York: IEEE, Article ID 7848822.
Open this publication in new window or tab >>A novel relaying scheme to guarantee timeliness and reliability in wireless networks
2017 (English)In: 2016 IEEE Globecom Workshops (GC Wkshps): Proceedings, New York: IEEE, 2017, article id 7848822Conference paper, Published paper (Refereed)
Abstract [en]

Many emerging applications based on wireless networks involve distributed control. This implies high requirements on reliability, but also on a predictable maximum delay and sometimes jitter. Further, many distributed control systems need to be constructed using off-the-shelf components, both due to cost constraints and due to interoperability with existing networks. This, in turn, implies that concurrent transmissions and multiuser detection are seldom possible. Instead, half-duplex time division multiple access (TDMA) is typically used. The total communication delay thereby depends on the packet error rate and the time until channel access is granted. With TDMA, channel access is upper-bounded and the jitter can be set to zero. With the aim to reduce the packet error rate given a certain deadline (a set of TDMA time-slots), we propose a novel relaying scheme, which can be implemented on top of off-the-shelf components. The paper includes a full analysis of the resulting error probability and latency. Numerical results show that the proposed relaying strategy significantly improves reliability given a certain maximum latency, or alternatively, reduces the latency, given a certain target reliability requirement. © 2016 IEEE.

Place, publisher, year, edition, pages
New York: IEEE, 2017
Keywords
Relaying Strategies, Reliability, Latency
National Category
Communication Systems
Identifiers
urn:nbn:se:hh:diva-32701 (URN)10.1109/GLOCOMW.2016.7848822 (DOI)000401921400025 ()2-s2.0-85015833222 (Scopus ID)978-1-5090-2482-7 (ISBN)978-1-5090-2481-0 (ISBN)
Conference
IEEE Globecom 2016 – 3rd International Workshop on Ultra-Reliable and Low-Latency Communications in Wireless Networks (URLLC), Washington, DC, USA, Dec. 8, 2016
Available from: 2016-12-15 Created: 2016-12-15 Last updated: 2017-12-11Bibliographically approved
Hoang, L.-N., Uhlemann, E. & Jonsson, M. (2017). Low Complexity Algorithm for Efficient Relay Assignment in Unicast/Broadcast Wireless Networks. In: 2017 IEEE 85th Vehicular Technology Conference (VTC Spring): . Paper presented at Vehicular Technology Conference, Sydney, Australia, 4-7 June, 2017. [S.l.]: IEEE
Open this publication in new window or tab >>Low Complexity Algorithm for Efficient Relay Assignment in Unicast/Broadcast Wireless Networks
2017 (English)In: 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), [S.l.]: IEEE, 2017Conference paper, Published paper (Refereed)
Abstract [en]

Using relayers in wireless networks enables higher throughput, increased reliability or reduced delay. However, when building networks using commercially available hardware, concurrent transmissions by multiple relayers are generally not possible. Instead one specific relayer needs to be assigned for each transmission instant. If the decision regarding which relayer to assign, i.e., which relayer that has the best opportunity to successfully deliver the packet, can be taken online, just before the transmission is to take place, much can be gained. This is particularly the case in mobile networks, as a frequently changing network topology considerably affects the choice of a suitable relayer. To this end, this paper addresses the problem of online relay assignment by developing a low-complexity algorithm highly likely to find the optimal combination of relaying nodes that minimizes the resulting error probability at the targeted receiver(s) using a mix of simulated annealing and ant colony algorithms, such that relay assignments can be made online also in large networks. The algorithm differs from existing works in that it considers both unicast as well as broadcast and assumes that all nodes can overhear each other, as opposed to separating source nodes, relay nodes and destination nodes into three disjoint sets, which is generally not the case in most wireless networks.

Place, publisher, year, edition, pages
[S.l.]: IEEE, 2017
Keywords
Relay Networks, Error Probability, Latency, Simulated Annealing, Ant Colony Optimization
National Category
Communication Systems
Identifiers
urn:nbn:se:hh:diva-35051 (URN)10.1109/VTCSpring.2017.8108261 (DOI)978-1-5090-5932-4 (ISBN)978-1-5090-5933-1 (ISBN)
Conference
Vehicular Technology Conference, Sydney, Australia, 4-7 June, 2017
Projects
ACDCREADYSafeCOP
Funder
Knowledge FoundationELLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications
Note

Additional funding: the ECSEL Joint Undertaking under grant agreements no 692529, and National funding

Available from: 2017-09-21 Created: 2017-09-21 Last updated: 2018-01-19Bibliographically approved
Hoang, L.-N. (2017). Relaying for Timely and Reliable Applications in Wireless Networks. (Doctoral dissertation). Halmstad: Halmstad University Press
Open this publication in new window or tab >>Relaying for Timely and Reliable Applications in Wireless Networks
2017 (English)Doctoral thesis, monograph (Other academic)
Abstract [en]

Many emerging applications based on wireless networks involve distributed control. This implies high requirements on reliability, but also on predictable maximum delay. Further, for applications, it is vital to use off-the-shelf components, both due to cost constraints and requirements on interoperability with existing networks. This, in turn, implies that concurrent transmissions and multiuser detection are seldom possible. Instead, half-duplex time-division multiple access (TDMA) is typically used. Aiming to reduce the packet error rate given a deadline (a set of TDMA time-slots), this thesis proposes a relaying scheme, which can be implemented on top of off-the-shelf components. The relaying scheme selects the best sequence of relayers, given the number of time-slots allowed by the deadline, such that the resulting error probability is minimized at the targeted receiver(s). The scheme differs from existing work in that it considers both unicast as well as broadcast and assumes that all nodes can overhear each other, as opposed to separating source nodes, relay nodes and destination nodes into three disjoint sets. A full analysis of the resulting error probability is provided and complementary numerical results show that the proposed relay sequencing strategy significantly improves reliability given a certain maximum delay, or alternatively, reduces the delay, given a certain target reliability requirement. To illustrate the performance improvements of relay sequencing, it is incorporated in a platooning application. If the decision regarding which relayer to assign in each time-slot can be taken online, just before the transmission, much can be gained. To this end, a low-complexity algorithm is developed, which is shown to be highly likely to find the optimal combination of relaying nodes that minimizes the resulting error probability at the targeted receiver(s). Data packets in wireless automation networks is typically small. To enable timely and reliable all-to-all broadcast in such systems, relay sequencing using packet aggregation is proposed. The strategy assigns relayers to time slots, as well as determines which packets to aggregate in each slot, using the proposed low-complexity algorithm. To further increase the reliability, a clustering scheme is proposed. When a relayer in the sequence fails to overhear a correct copy, a backup relayer in the cluster takes over. This work thereby enables ultra-reliable communications with maintained end-toend delay using low-complexity techniques and off-the-shelf components.

Place, publisher, year, edition, pages
Halmstad: Halmstad University Press, 2017. p. 68
Series
Halmstad University Dissertations ; 35
National Category
Communication Systems
Identifiers
urn:nbn:se:hh:diva-35172 (URN)978-91-87045-72-1 (ISBN)978-91-87045-73-8 (ISBN)
Public defence
2017-11-03, Wigforss, House J (Visionen), Kristian IV:s väg 3, Halmstad, 13:15 (English)
Opponent
Supervisors
Available from: 2017-10-17 Created: 2017-10-10 Last updated: 2017-10-31Bibliographically approved
Hoang, L.-N., Uhlemann, E. & Jonsson, M. (2017). Relaying with Packet Aggregation for Half-Duplex All-to-All Broadcast in Time-Critical Wireless Networks. In: 2017 IEEE Globecom Workshops (GC Wkshps): . Paper presented at 2017 IEEE Global Telecommunications (GLOBECOM), Singapore, Singapore, December 4-8, 2017. Piscataway, NJ: IEEE
Open this publication in new window or tab >>Relaying with Packet Aggregation for Half-Duplex All-to-All Broadcast in Time-Critical Wireless Networks
2017 (English)In: 2017 IEEE Globecom Workshops (GC Wkshps), Piscataway, NJ: IEEE, 2017Conference paper, Published paper (Other academic)
Abstract [en]

Wireless automation and control networks, with stringent latency and reliability requirements, typically use half-duplex communications combined with deadline-aware scheduling of time slots to nodes. To introduce higher reliability in legacy industrial control systems, extra time slots are usually reserved for retransmissions. However, in distributed wireless control systems, where sensor data from several different nodes must be timely and reliably available at all places where controller decisions are made, this is particularly cumbersome as all nodes may not hear each other and extra time slots imply increased delay. To enable all-to-all broadcast with manageable overhead and complexity in such systems, we therefore propose a novel relaying strategy using packet aggregation. The strategy assigns relayers to time slots, as well as determines which packets to aggregate in each slot, using a low-complexity algorithm such that ultra-reliable communications can be obtained with maintained end-to-end latency.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE, 2017
Keywords
Broadcasting, Error Probability, Latency, Reliability
National Category
Communication Systems
Identifiers
urn:nbn:se:hh:diva-35192 (URN)10.1109/GLOCOMW.2017.8269134 (DOI)978-1-5386-3920-7 (ISBN)978-1-5386-3921-4 (ISBN)
Conference
2017 IEEE Global Telecommunications (GLOBECOM), Singapore, Singapore, December 4-8, 2017
Projects
SIDUSSafeCOP
Funder
Knowledge Foundation, 20130086 READY
Note

As manuscript in thesis; Funding: Knowledge Foundation through the SIDUS project 20130086 READY and from the SafeCOP project, funded from the ECSEL Joint Undertaking under grant agreement n 692529, and from National funding.

Available from: 2017-10-13 Created: 2017-10-13 Last updated: 2018-03-13Bibliographically approved
Hoang, L.-N., Uhlemann, E. & Jonsson, M. (2015). A Framework for Reliable Exchange of Periodic and Event-Driven Messages in Platoons. In: 2015 IEEE International Conference on Communication Workshop: . Paper presented at EEE International Conference on Communication Workshop, ICCW 2015, London, United Kingdom, 8 – 12 June, 2015 (pp. 2471-2476). Piscataway: IEEE conference proceedings
Open this publication in new window or tab >>A Framework for Reliable Exchange of Periodic and Event-Driven Messages in Platoons
2015 (English)In: 2015 IEEE International Conference on Communication Workshop, Piscataway: IEEE conference proceedings, 2015, p. 2471-2476Conference paper, Published paper (Refereed)
Abstract [en]

Platooning is widely considered a promising approach to decrease fuel consumption by reducing the air drag. However, in order to achieve the benefits of aerodynamic efficiency, the inter-vehicle distances must be kept short. This implies that the intra-platoon communication must not only be reliable but also able to meet strict timing deadlines. In this paper, we propose a framework that reliably handles the co-existence of both time-triggered and event-driven control messages in platooning applications and we derive an efficient message dissemination technique. We propose a semi-centralized time division multiple access (TDMA) approach, which e.g., can be placed on top of the current standard IEEE 802.11p and we evaluate the resulting error probability and delay, when using it to broadcast periodic beacons and disseminating eventdriven messages within a platoon. Simulation results indicate that the proposed dissemination policy significantly enhances the reliability for a given number of available time-slots, or alternatively, reduces the delay, in terms of time-slots, required to achieve a certain target error probability, without degrading the performance of co-existing time-triggered messages. © 2015 IEEE

Place, publisher, year, edition, pages
Piscataway: IEEE conference proceedings, 2015
Series
IEEE International Conference on Communication Workshop, ISSN 2164-7038 ; 2015
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:hh:diva-28231 (URN)10.1109/ICCW.2015.7247547 (DOI)000380459900401 ()2-s2.0-84947775613 (Scopus ID)978-1-4673-6305-1 (ISBN)
Conference
EEE International Conference on Communication Workshop, ICCW 2015, London, United Kingdom, 8 – 12 June, 2015
Projects
ACDC
Funder
Knowledge Foundation
Available from: 2015-05-08 Created: 2015-05-08 Last updated: 2018-03-22Bibliographically approved
Hoang, L.-N., Uhlemann, E. & Jonsson, M. (2015). A Simple Relaying Scheme to Guarantee Timeliness and Reliability in Wireless Networks.
Open this publication in new window or tab >>A Simple Relaying Scheme to Guarantee Timeliness and Reliability in Wireless Networks
2015 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Many emerging applications based on wireless networks involves distributed control. This implies high requirements on reliability, but also on maximum delay and sometimes jitter. The total delay depends on the packet error rate and the time until channel access is granted. With e.g., TDMA, channel access is upper-bounded and the jitter zero. To reduce the packet error rate given a certain deadline (a set of TDMA time-slots), we propose a simple relaying scheme, including a full analysis of its resulting error probability and delay. Numerical results show that the proposed relaying strategy significantly improves reliability given a certain message deadline.

National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:hh:diva-28243 (URN)
Projects
ACDC
Funder
Knowledge FoundationeLLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications
Available from: 2015-05-11 Created: 2015-05-11 Last updated: 2018-03-22Bibliographically approved
Hoang, L.-N., Uhlemann, E. & Jonsson, M. (2015). An Efficient Message Dissemination Technique in Platooning Applications. IEEE Communications Letters, 19(6), 1017-1020
Open this publication in new window or tab >>An Efficient Message Dissemination Technique in Platooning Applications
2015 (English)In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 19, no 6, p. 1017-1020Article in journal (Refereed) Published
Abstract [en]

Autonomous driving in road trains, a.k.a. platooning, may reduce fuel consumption considerably if the intervehicle distances are kept short. However, to do this, the intraplatoon communication must not only be reliable but also able to meet strict deadlines. While time-triggered messages are the foundation of most distributed control applications, platooning is likely to also require dissemination of event-driven messages. While much research work has focused on minimizing the age of periodic messages, state-of-the-art for disseminating eventdriven messages is to let all nodes repeat all messages and focus on mitigating broadcast storms. We derive an efficient message dissemination scheme based on relay selection which minimizes the probability of error at the intended receiver(s) for both unicast and broadcast, without degrading the performance of co-existing time-triggered messages. We present a full analysis of the resulting error probability and delay, when relayers, selected by our algorithm, are used to disseminate messages within a platoon. Numerical results indicate that the proposed relaying policy significantly enhances the reliability for a given delay.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Press, 2015
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:hh:diva-28228 (URN)10.1109/LCOMM.2015.2416174 (DOI)000356164000032 ()2-s2.0-84933507762 (Scopus ID)
Projects
ACDC
Funder
Knowledge Foundation
Available from: 2015-05-08 Created: 2015-05-08 Last updated: 2018-03-22Bibliographically approved
Hoang, L.-N. (2015). Relaying for Timely and Reliable Message Dissemination in Wireless Distributed Control Systems. (Licentiate dissertation). Halmstad: Halmstad University Press
Open this publication in new window or tab >>Relaying for Timely and Reliable Message Dissemination in Wireless Distributed Control Systems
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Distributed control applications enabled by wireless networks are becoming more and more frequent. The advantages of wireless access are many, as control systems become mobile, autonomous and connected. Examples include platooning and automated factories. However, distributed control systems have stringent requirement on both reliability and timeliness, the latter in terms of deadlines. If the deadline is missed, the packet is considered useless, similarly to a lost or erroneous packet in a system without deadlines. In addition, wireless channels are, by nature, more exposed to noise and interference than their wired counterparts. Consequently, it implies a considerable challenge to fulfill the deadline requirements with sufficient reliability for proper functionality of distributed control applications. However, by taking advantage of cooperative communications, increased reliability can be achieved with little or no additional delay.

Reducing the delay until a message is successfully received is a two-fold problem: providing channel access with a predictable maximum delay and maximizing the reliability of each transmission, once granted by the medium access method. To this end, this thesis proposes a framework that provides a bounded channel access delay and handles the co-existence of both time-triggered and event-driven messages encountered in distributed control applications. In addition, the thesis proposes and evaluates an efficient message dissemination technique based on relaying that maximizes the reliability given a certain deadline, or alternatively determines the delay required to achieve a certain reliability threshold for both unicast and broadcast scenarios. Numerical results, which are verified by Monte-Carlo simulations, show significant improvements with the proposed relaying scheme as compared to a conventional scheme without cooperation, providing more reliable message delivery given a fixed number of available time-slots. It also becomes clear in which situations relaying is preferable and in which situations pure retransmissions are preferable, as the relay selection algorithm will always pick the best option. The relay selection algorithm has a reasonable complexity and can be used by both routing algorithms and relaying scenarios in any time-critical application as long as it is used together with a framework that enables predictable channel access. In addition, it can be implemented on top of commercially available transceivers.

Place, publisher, year, edition, pages
Halmstad: Halmstad University Press, 2015. p. 58
Series
Halmstad University Dissertations ; 14
National Category
Communication Systems Telecommunications
Identifiers
urn:nbn:se:hh:diva-28245 (URN)978-91-87045-31-8 (ISBN)978-91-87045-30-1 (ISBN)
Presentation
2015-06-01, Haldasalen, Visionen, Högskolan i Halmstad, Kristian IV:s väg 3, Halmstad, 13:15 (English)
Opponent
Supervisors
Projects
ACDC
Funder
Knowledge FoundationeLLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications
Available from: 2015-05-12 Created: 2015-05-11 Last updated: 2018-03-22Bibliographically approved
Hoang, L.-N., Uhlemann, E. & Jonsson, M. Cluster Relaying to Guarantee Timeliness and Reliability in Wireless Networks.
Open this publication in new window or tab >>Cluster Relaying to Guarantee Timeliness and Reliability in Wireless Networks
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Many emerging applications using wireless networks imply high requirements on reliability, but also on a predictable maximum delay. Due to cost constraints and interoperability with existing networks, half-duplex time division multiple access (TDMA) is typically used in these applications. With TDMA, channel access is upper-bounded and the jitter can be set to zero. However, the major drawback of TDMA is that the already-allocated time-slots are wasted if their respective transmitters do not have any packet to send. Therefore, in this paper we propose a novel cluster-relaying scheme to overcome this drawback but still reduce the probability of error given a certain deadline. Numerical results show that the proposed scheme significantly enhances reliability while guaranteeing deadline for each message.

Keywords
Relays, Reliability, Latency, Clustering
National Category
Communication Systems
Identifiers
urn:nbn:se:hh:diva-35205 (URN)
Note

Submitted

Available from: 2017-10-17 Created: 2017-10-17 Last updated: 2019-01-14
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