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| 2. |
- Hwang, YoungJu, et al.
(författare)
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On the throughput gain of device-to-device communications
- 2015
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Ingår i: ICT Express. - : Elsevier. - 2405-9595. ; 1:2, s. 67-70
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Tidskriftsartikel (refereegranskat)abstract
- In an uplink underlaid device-to-device (D2D) cellular network, this paper considers its two aspects of throughput improvement. The two-fold gain comprises the throughput increase by offloading downlink cellular traffic to D2D communications, duplexing gain, and the increase by reusing uplink resources of D2D transmissions, capacity gain. Both impacts are investigated by exploiting stochastic geometry. On the basis of the analysis, a throughput optimal D2D operation guideline is provided for different network congestion environments.
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| 3. |
- Kim, Jeemin, et al.
(författare)
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Millimeter-Wave Interference Avoidance via Building-Aware Associations
- 2018
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Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 6, s. 10618-10634
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Tidskriftsartikel (refereegranskat)abstract
- Signal occlusion by building blockages is a double-edged sword for the performance of millimeter-wave (mmW) communication networks. Buildings may dominantly attenuate the useful signals, especially when mmW base stations (BSs) are sparsely deployed compared with the building density. In the opposite BS deployment, buildings can block the undesired interference. To enjoy only the benefit, we propose a building-aware association scheme that adjusts the directional BS association bias of the user equipments (UEs), based on a given building density and the concentration of UE locations around the buildings. The association of each BS can thereby be biased: 1) toward the UEs located against buildings for avoiding interference to other UEs or 2) toward the UEs providing their maximum reference signal received powers. The proposed association scheme is optimized to maximize the downlink average data rate derived by stochastic geometry. Its effectiveness is validated by simulation using real building statistics.
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| 4. |
- Park, Jihong, et al.
(författare)
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Tractable Resource Management With Uplink Decoupled Millimeter-Wave Overlay in Ultra-Dense Cellular Networks
- 2016
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Ingår i: IEEE Transactions on Wireless Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 1536-1276 .- 1558-2248. ; 15:6, s. 4362-4379
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Tidskriftsartikel (refereegranskat)abstract
- The forthcoming 5G cellular network is expected to overlay millimeter-wave (mmW) transmissions with the incumbent micro-wave (mu W) architecture. The overall mm-mu Wresource management should, therefore, harmonize with each other. This paper aims at maximizing the overall downlink (DL) rate with a minimum uplink (UL) rate constraint, and concludes: mmWtends to focus more on DL transmissions while mu W has high priority for complementing UL, under time-division duplex (TDD) mmW operations. Such UL dedication of mu W results from the limited use of mmW UL bandwidth due to excessive power consumption and/or high peak-to-average power ratio (PAPR) at mobile users. To further relieve this UL bottleneck, we propose mmW UL decoupling that allows each legacy mu Wbase station (BS) to receive mmW signals. Its impact on mm-mu W resource management is provided in a tractable way by virtue of a novel closed-form mm-mu W spectral efficiency (SE) derivation. In an ultra-dense cellular network (UDN), our derivation verifies mmW (or mu W) SE is a logarithmic function of BS-to-user density ratio. This strikingly simple yet practically valid analysis is enabled by exploiting stochastic geometry in conjunction with real three-dimensional (3-D) building blockage statistics in Seoul, South Korea.
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| 5. |
- Popovski, Petar, et al.
(författare)
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Wireless Access for Ultra-Reliable Low-Latency Communication (URLLC): Principles and Building Blocks
- 2018
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Ingår i: IEEE Network. - 1558-156X .- 0890-8044. ; 32:2, s. 16-23
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Tidskriftsartikel (refereegranskat)abstract
- Ultra-reliable low latency communication (URLLC) is an important new feature brought by 5G, with a potential to support a vast set of applications that rely on mission-critical links. In this article, we first discuss the principles for supporting URLLC from the perspective of the traditional assumptions and models applied in communication/information theory. We then discuss how these principles are applied in various elements of the system design, such as use of various diversity sources, design of packets and access protocols. The important messages are that there is a need to optimize the transmission of signaling information, as well as a need for a lean use of various sources of diversity.
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| 6. |
- Yang, Yanpeng, 1987-, et al.
(författare)
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Cooperative Transmissions in Ultra-Dense Networks under a Bounded Dual-Slope Path Loss Model
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In an Ultra-dense network (UDN) where there aremore base stations (BSs) than active users, it is possible thatmany BSs are instantaneously left idle. Thus, how to utilizethese dormant BSs by means of cooperative transmission is aninteresting question. In this paper, we investigate the performanceof a UDN with two types of cooperation schemes: non-coherentjoint transmission (JT) without channel state information (CSI)and coherent JT with full CSI knowledge. We consider a boundeddual-slope path loss model to describe UDN environments wherea user has several BSs in the near-field and the rest in thefar-field. Numerical results show that non-coherent JT cannotimprove the user spectral efficiency (SE) due to the simultaneousincrement in signal and interference powers. For coherent JT, theachievable SE gain depends on the range of near-field, the relativedensities of BSs and users, and the CSI accuracy. Finally, weassess the energy efficiency (EE) of cooperation in UDN. Despitecosting extra energy consumption, cooperation can still improveEE under certain conditions.
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| 7. |
- Yang, Yanpeng, 1987-, et al.
(författare)
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On the Asymptotic Behavior of Ultra-Densificationunder a Bounded Dual-Slope Path Loss Model
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, we investigate the impact of networkdensification on the performance in terms of downlink signal-tointerference(SIR) coverage probability and network area spectralefficiency (ASE). A sophisticated bounded dual-slope path lossmodel and practical UE densities are incorporated in the analysis.By using stochastic geometry, we derive an integral expressionalong with closed-form bounds of the coverage probability andASE, validated by simulation results. Through these, we providethe asymptotic behavior of ultra-densification. The coverageprobability and ASE have non-zero convergence in asymptoticregions unless UE density goes to infinity (full load). Meanwhile,the effect of UE density on the coverage probability is analyzed.The coverage probability will suffer from decreasing with largeUE densities due to interference fall into the near-field, but it willkeep increasing with lower UE densites. Furthermore, we showthe performance is overestimated without applying the boundeddual-slope path loss model. Our study can give insights on efficientnetwork provisioning in the future.
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