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Yuan, Di
Publications (10 of 21) Show all publications
Ecker, G., Yuan, D., Koster, A. M. C. & Schmeink, A. (2019). Accurate optimization models for interference constrained bandwith allocation in cellular networks. Computers & Operations Research, 101, 1-12
Open this publication in new window or tab >>Accurate optimization models for interference constrained bandwith allocation in cellular networks
2019 (English)In: Computers & Operations Research, ISSN 0305-0548, E-ISSN 1873-765X, Vol. 101, p. 1-12Article in journal (Refereed) Published
Abstract [en]

In cellular networks, the signal-to-interference-plus-noise ratio (SINR) is a key metric for link availability and quality. For network planning purposes, a straightforward modeling unfortunately yields numerically difficult optimization models. Further, given a required data rate of a link, its bandwidth consumption depends nonlinearly on the SINR.

In this paper, we develop two novel approaches to jointly model SINR-based link availability and bandwidth requirements accurately. The first approach is a set-wise formulation from a user’s point of view, while the second one exploits discrete channel quality indicators. We compare these formulations with three known approximate approaches numerically, revealing the clear outperformance of our approaches in terms of exactness. Moreover, since the exact models comprise an exponential number of either variables or constraints, we discuss their pros and cons in a further computational study and develop a more efficient algorithm dealing implicitly with the involved constraints.

National Category
Computer Sciences
Identifiers
urn:nbn:se:uu:diva-367379 (URN)10.1016/j.cor.2018.08.011 (DOI)000449311100001 ()
Funder
German Research Foundation (DFG), KO2311/3-1German Research Foundation (DFG), SCHM2643/5-1EU, Horizon 2020, 645705
Available from: 2018-08-22 Created: 2018-11-30 Last updated: 2019-12-06Bibliographically approved
Ahani, G. & Yuan, D. (2019). BS-assisted Task Offloading for D2D Networks with Presence of User Mobility. In: 2019 IEEE 89TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2019-SPRING): . Paper presented at 89th IEEE Vehicular Technology Conference (VTC Spring), APR 28-MAY 01, 2019, Kuala Lumpur, MALAYSIA. IEEE
Open this publication in new window or tab >>BS-assisted Task Offloading for D2D Networks with Presence of User Mobility
2019 (English)In: 2019 IEEE 89TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2019-SPRING), IEEE , 2019Conference paper, Published paper (Refereed)
Abstract [en]

Task offloading is a key component in mobile edge computing. Offloading a task to a remote server takes communication and networking resources. An alternative is device-to-device (D2D) offloading, where a task of a device is offloaded to some device having computational resource available. The latter requires that the devices are within the range of each other, first for task collection, and later for result gathering. Hence, in mobility scenarios, the performance of D2D offloading will suffer if the contact rates between the devices are low. We enhance the setup to base station (BS) assisted D2D offloading, namely, a BS can act as a relay for task distribution or result collection. However, this would imply additional consumption of wireless resources. The associated cost and the improvement in completion time of task offloading compose a fundamental trade-off. For the resulting optimization problem, we mathematically prove the complexity, and propose an algorithm using Lagrangian duality. The simulation results demonstrate not only that the algorithm has close-to-optimal performance, but also provide structural insights of the optimal trade-off.

Place, publisher, year, edition, pages
IEEE, 2019
Series
IEEE Vehicular Technology Conference Proceedings, ISSN 1550-2252
Keywords
Task offloading, D2D communications, Mobility, Base station, Relay
National Category
Computer Sciences
Identifiers
urn:nbn:se:uu:diva-394727 (URN)10.1109/VTCSpring.2019.8746650 (DOI)000482655600307 ()978-1-7281-1217-6 (ISBN)
Conference
89th IEEE Vehicular Technology Conference (VTC Spring), APR 28-MAY 01, 2019, Kuala Lumpur, MALAYSIA
Available from: 2019-10-11 Created: 2019-10-11 Last updated: 2019-10-11Bibliographically approved
Lei, L., You, L., Yang, Y., Yuan, D., Chatzinotas, S. & Ottersten, B. (2019). Load Coupling and Energy Optimization in Multi-Cell and Multi-Carrier NOMA Networks. IEEE Transactions on Vehicular Technology, 68(11), 11323-11337
Open this publication in new window or tab >>Load Coupling and Energy Optimization in Multi-Cell and Multi-Carrier NOMA Networks
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2019 (English)In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 68, no 11, p. 11323-11337Article in journal (Refereed) Published
Abstract [en]

In this paper, we investigate energy optimization in multi-cell and multi-carrier non-orthogonal multiple access (NOMA) networks. We apply a load-coupling model for NOMA networks to capture the coupling relation of mutual interference among cells. With this analytical tool, we formulate an energy minimization problem in a NOMA-based load-coupled system, where optimizing load-rate-power allocation, and determining decoding order and user grouping are the key aspects. Theoretically, we prove that the minimum consumed energy can be achieved by using all the time-frequency resources in each cell to deliver users' demand, and allowing all the users to share resource units. From a practical perspective, we consider three types of NOMA grouping schemes, i.e., all-user grouping, partitioned and non-partitioned grouping. We develop tailored solutions for each grouping scheme to enable efficient load-rate-power optimization. These three algorithmic components are embedded into a power-adjustment framework to provide energy-efficient solutions for NOMA networks. Numerical results demonstrate promising energy-saving gains of NOMA over orthogonal multiple access in large-scale cellular networks, in particular for high-demand and resource-limited scenarios. The results also show fast convergence of the proposed algorithms and demonstrate the effectiveness of the solutions.

Keywords
Non-orthogonal multiple access (NOMA), load coupling, resource allocation, energy minimization
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-400757 (URN)10.1109/TVT.2019.2943701 (DOI)000501358800079 ()
Funder
Swedish Research Council
Available from: 2020-01-03 Created: 2020-01-03 Last updated: 2020-01-03Bibliographically approved
Deng, T., Fan, P. & Yuan, D. (2019). Optimizing Retention-Aware Caching in Vehicular Networks. IEEE Transactions on Communications, 67(9), 6139-6152
Open this publication in new window or tab >>Optimizing Retention-Aware Caching in Vehicular Networks
2019 (English)In: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 67, no 9, p. 6139-6152Article in journal (Refereed) Published
Abstract [en]

Caching is an effective way to address the challenges due to explosive data traffic growth and massive device connectivity in fifth-generation (5G) networks. Currently, few works on caching pay attention to the impact of the time duration for which content is stored, called retention time, on caching optimization. The research on retention time is motivated by two practical issues, i.e., flash memory damage and storage rental cost in cloud networks, together giving rise to the storage cost. How to optimize caching contents taking the storage cost into consideration is a challenging problem, especially for the scenarios with cache-enabled mobile nodes. In this paper, a retention-aware caching problem (RACP) in vehicular networks is formulated, considering the impact of the storage cost. The problem's complexity analysis is provided. For symmetric cases, an optimal dynamic programming (DP) algorithm with polynomial time complexity is derived. For general cases, a low complexity and effective retention aware multi-helper caching algorithm (RAMA) is proposed. Numerical results are used to verify the effectiveness of the algorithms.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Caching, storage cost, vehicular networks
National Category
Telecommunications Communication Systems
Identifiers
urn:nbn:se:uu:diva-395701 (URN)10.1109/TCOMM.2019.2921368 (DOI)000487048400017 ()
Funder
Swedish Research Council, 2018-05247
Available from: 2019-10-23 Created: 2019-10-23 Last updated: 2019-10-23Bibliographically approved
Wiatr, P., Chen, J., Monti, P., Wosinska, L. & Yuan, D. (2019). Routing and wavelength assignment vs EDFA reliability performance in optical backbone networks: An operational cost perspective. Optical Switching and Networkning Journal, 31, 211-217
Open this publication in new window or tab >>Routing and wavelength assignment vs EDFA reliability performance in optical backbone networks: An operational cost perspective
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2019 (English)In: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 31, p. 211-217Article in journal (Refereed) Published
Abstract [en]

A failure in optical backbone network can cause tremendous consequences as a substantial number of connections often each carrying a large amount of data can be interrupted. Therefore, high reliability performance is essential for the network operators. Many existing works that aim at improving network reliability performance implicitly assume that the lifetime of devices is constant and independent of the traffic load. However, the reliability performance of a device is related to its occupancy. For example, the failure rate of erbium doped fiber amplifier (EDFA) can be expressed as a function of the number of amplified wavelengths. On the other hand, the choice of routing and wavelength assignment (RWA) algorithm impacts the link load and, as a consequence, can influence the number of EDFA failures in the network.

In this paper we examine how RWA can impact the failure reparation related network operational costs. Several types of RWA approaches are considered, namely load-balancing, energy-awareness, and reliability-awareness. Among all the considered RWA algorithms, the reliability-aware RWA (RA-RWA) approach leverages on EDFA reliability profile to reduce the number of EDFA failures in the network and the related operational costs.

The simulation results show that the RWA algorithm impacts in a significant way the operational costs caused by EDFA failures. The cost associated with reparation of an EDFA decreases by 7.8% (in case of RA-RWA) and increases by up to 40% (in case of a load-balancing approach) compared to the classical Shortest Path (SP) approach. Moreover, the cost caused by connection rerouting due to link unavailability triggered by EDFA failure exhibits a 20% decrease (RA-RWA) and up to 94% increase (energy-aware algorithm). We also analyze some key network performance metrics that may be affected by RWA, including blocking probability, link occupancy distribution, and path length.

National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-367380 (URN)10.1016/j.osn.2018.10.005 (DOI)000454380100018 ()
Funder
Swedish Research Council
Available from: 2018-10-26 Created: 2018-11-30 Last updated: 2019-01-15Bibliographically approved
Deng, T., Ahani, G., Fan, P. & Yuan, D. (2018). Cost-optimal caching for D2D networks with user mobility: Modeling, analysis, and computational approaches. IEEE Transactions on Wireless Communications, 17(5), 3082-3094
Open this publication in new window or tab >>Cost-optimal caching for D2D networks with user mobility: Modeling, analysis, and computational approaches
2018 (English)In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 17, no 5, p. 3082-3094Article in journal (Refereed) Published
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-356502 (URN)10.1109/TWC.2018.2806451 (DOI)000432014300019 ()
Available from: 2018-02-22 Created: 2018-07-30 Last updated: 2018-11-30Bibliographically approved
Deng, T., You, L., Fan, P. & Yuan, D. (2018). Device caching for network offloading: Delay minimization with presence of user mobility. IEEE Wireless Communications Letters, 7(4), 558-561
Open this publication in new window or tab >>Device caching for network offloading: Delay minimization with presence of user mobility
2018 (English)In: IEEE Wireless Communications Letters, ISSN 2162-2337, E-ISSN 2162-2345, Vol. 7, no 4, p. 558-561Article in journal (Refereed) Published
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-363997 (URN)10.1109/LWC.2018.2795617 (DOI)000442368700018 ()
Available from: 2018-01-23 Created: 2018-11-05 Last updated: 2018-12-03Bibliographically approved
Lei, L., Vu, T. X., You, L., Fowler, S. & Yuan, D. (2018). Efficient minimum-energy scheduling with machine-learning based predictions for multiuser MISO systems. In: Proc. International Conference on Communications: ICC 2018. Paper presented at ICC 2018, May 20–24, Kansas City, MO. IEEE Communications Society
Open this publication in new window or tab >>Efficient minimum-energy scheduling with machine-learning based predictions for multiuser MISO systems
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2018 (English)In: Proc. International Conference on Communications: ICC 2018, IEEE Communications Society, 2018Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
IEEE Communications Society, 2018
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-368024 (URN)10.1109/ICC.2018.8422520 (DOI)978-1-5386-3180-5 (ISBN)
Conference
ICC 2018, May 20–24, Kansas City, MO
Available from: 2018-07-31 Created: 2018-12-03 Last updated: 2018-12-03Bibliographically approved
Ahani, G. & Yuan, D. (2018). On optimal proactive and retention-aware caching with user mobility. In: 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall): . Paper presented at 88th IEEE Vehicular Technology Conference (VTC-Fall), AUG 27-30, 2018, Chicago, IL. IEEE
Open this publication in new window or tab >>On optimal proactive and retention-aware caching with user mobility
2018 (English)In: 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), IEEE, 2018Conference paper, Published paper (Refereed)
Abstract [en]

Caching popular contents at edge devices is an effective solution to alleviate the burden of the backhaul networks. Earlier investigations commonly neglected the storage cost in caching. More recently, retention-aware caching, where both the downloading cost and storage cost are accounted for, is attracting attention. Motivated by this, we address proactive and retention-aware caching problem with the presence of user mobility, optimizing the sum of the two types of costs. More precisely, a cost-optimal caching problem for vehicle-to-vehicle networks is formulated with joint consideration of the impact of the number of vehicles, cache size, storage cost, and content request probability. This is a combinatorial optimization problem. However, we derive a stream of analytical results and they together lead to an algorithm that guarantees global optimum with polynomial-time complexity. Numerical results show significant improvements in comparison to popular caching and random caching.

Place, publisher, year, edition, pages
IEEE, 2018
Series
IEEE Vehicular Technology Conference Proceedings, ISSN 1550-2252
National Category
Telecommunications
Identifiers
urn:nbn:se:uu:diva-368071 (URN)10.1109/VTCFall.2018.8691020 (DOI)000468872400462 ()978-1-5386-6358-5 (ISBN)
Conference
88th IEEE Vehicular Technology Conference (VTC-Fall), AUG 27-30, 2018, Chicago, IL
Available from: 2019-04-15 Created: 2018-12-03 Last updated: 2019-08-02Bibliographically approved
Wiatr, P., Yuan, D., Wosinska, L. & Chen, J. (2018). Optical Interconnect Architectures for Datacenters. In: Winzer, P Tsang, HK Capmany, J Yao, J Fontaine, N Dutta, N (Ed.), 2018 IEEE Photonics Conference (IPC): . Paper presented at 31st Annual IEEE Photonics Conference (IPC) of the IEEE-Photonics-Society, SEP 30-OCT 04, 2018, Reston, VA. IEEE
Open this publication in new window or tab >>Optical Interconnect Architectures for Datacenters
2018 (English)In: 2018 IEEE Photonics Conference (IPC) / [ed] Winzer, P Tsang, HK Capmany, J Yao, J Fontaine, N Dutta, N, IEEE, 2018Conference paper, Published paper (Refereed)
Abstract [en]

This paper highlights the challenges faced by the current datacenter networks, where using photonic technology offers a numbers of obvious advantages. Some existing optical intra-datacenter network architectures will be presented along with new ideas allowing for reduction of energy consumption and required spectrum resources.

Place, publisher, year, edition, pages
IEEE, 2018
Series
IEEE Photonics Conference, ISSN 2374-0140
Keywords
optical interconnects, datacenters, AWG, broadcast and select, splitter, H-coupler
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-379954 (URN)10.1109/IPCon.2018.8527245 (DOI)000460542800154 ()978-1-5386-5358-6 (ISBN)
Conference
31st Annual IEEE Photonics Conference (IPC) of the IEEE-Photonics-Society, SEP 30-OCT 04, 2018, Reston, VA
Funder
Swedish Research CouncilVinnova, C2015/3-3
Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-03-25Bibliographically approved
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