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Publications (8 of 8) Show all publications
Kim, D., Yang, Y., Sung, K. W. & Kang, J. (2018). Cooperation Strategies for Partly Wireless C-RAN. IEEE Communications Letters, 22(6), 1248-1251
Open this publication in new window or tab >>Cooperation Strategies for Partly Wireless C-RAN
2018 (English)In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 22, no 6, p. 1248-1251Article in journal (Refereed) Published
Abstract [en]

This letter presents a variant of cloud radio access network (C-RAN) architecture, which we term partly wireless C-RAN (PW-CRAN). It is characterized by extra radio nodes connected through the existing remote radio heads. Because of the newly connected nodes and the consequent additional delay, the operation of PW-CRAN requires different approaches compared with that of the typical C-RAN. Specifically, the effect of delayed channel state information on the suitability of network cooperation should be identified. To tackle this problem, we introduce two representative cooperation strategies and evaluate the performance with regard to the delay via simulations. Numerical results suggest that it is better to exclude the extra nodes from cooperation if they incur excess delay. Furthermore, whether the delay is deemed excessive depends on the interference environment. Hence, we provide quantified guidelines on the cooperation strategy of PW-CRAN.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
Cloud radio access network, cooperation strategy, fronthaul link, delay, imperfect channel state information
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Communication Systems
Identifiers
urn:nbn:se:kth:diva-231721 (URN)10.1109/LCOMM.2018.2807814 (DOI)000435175800035 ()2-s2.0-85042172488 (Scopus ID)
Note

QC 20180815

Available from: 2018-08-15 Created: 2018-08-15 Last updated: 2018-11-20Bibliographically approved
Shokri-Ghadikolaei, H., Yang, Y., Petrova, M., Sung, K. W. & Fischione, C. (2018). Fast and Reliable Initial Cell-search for mmWave Networks. In: : . Paper presented at 2nd ACM Workshop on Millimeter-Wave Networks and Sensing Systems 2018 (mmNets’18) (pp. 57-62). Association for Computing Machinery (ACM)
Open this publication in new window or tab >>Fast and Reliable Initial Cell-search for mmWave Networks
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2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

In millimeter-wave wireless networks, the use of narrow beams, required to compensate for the severe path-loss, complicates the cell-discovery and initial access. In this paper, we investigate the feasibility of random beam forming and enhanced exhaustive search for cell-discovery by analyzing the latency and detection failure probability in the control-plane and the user throughput in the data-plane. We show that, under realistic propagation model and antenna patterns, both approaches are suitable for 3GPP New Radio cellular networks. The performance gain, compared to the heavily used exhaustive and iterative search schemes, is more prominent in dense networks and large antenna regimes and can be further improved by optimizing the beam forming code-books.

Place, publisher, year, edition, pages
Association for Computing Machinery (ACM), 2018
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-239140 (URN)10.1145/3264492.3264502 (DOI)000480467200011 ()2-s2.0-85061490095 (Scopus ID)978-1-4503-5928-3 (ISBN)
Conference
2nd ACM Workshop on Millimeter-Wave Networks and Sensing Systems 2018 (mmNets’18)
Note

QC 20181119

Available from: 2018-11-16 Created: 2018-11-16 Last updated: 2019-09-03Bibliographically approved
Yang, Y., Sung, K. W., Park, J., Kim, S.-L. -. & Kim, K. S. (2017). Cooperative transmissions in ultra-dense networks under a bounded dual-slope path loss model. In: 2017 European Conference on Networks and Communications (EuCNC): . Paper presented at 2017 European Conference on Networks and Communications, EuCNC 2017, Oulu, Finland, 12 June 2017 through 15 June 2017. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Cooperative transmissions in ultra-dense networks under a bounded dual-slope path loss model
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2017 (English)In: 2017 European Conference on Networks and Communications (EuCNC), Institute of Electrical and Electronics Engineers (IEEE), 2017Conference paper, Published paper (Refereed)
Abstract [en]

In an ultra-dense network (UDN) where there are more base stations (BSs) than active users, it is possible that many BSs are instantaneously left idle. Thus, how to utilize these dormant BSs by means of cooperative transmission is an interesting question. In this paper, we investigate the performance of a UDN with two types of cooperation schemes: Non-coherent joint transmission (JT) without channel state information (CSI) and coherent JT with full CSI knowledge. We consider a bounded dual-slope path loss model to describe UDN environments where a user has several BSs in the near-field and the rest in the far-field. Numerical results show that non-coherent JT cannot improve the user spectral efficiency (SE) due to the simultaneous increment in signal and interference powers. For coherent JT, the achievable SE gain depends on the range of near-field, the relative densities of BSs and users, and the CSI accuracy. Finally, we assess the energy efficiency (EE) of cooperation in UDN. Despite costing extra energy consumption, cooperation can still improve EE under certain conditions.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Keywords
bounded path loss model, cooperative transmissions, multi-slope path loss model, Ultra-dense networks
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-221121 (URN)10.1109/EuCNC.2017.7980732 (DOI)2-s2.0-85039946526 (Scopus ID)9781538638736 (ISBN)
Conference
2017 European Conference on Networks and Communications, EuCNC 2017, Oulu, Finland, 12 June 2017 through 15 June 2017
Note

QC 20180115

Available from: 2018-01-15 Created: 2018-01-15 Last updated: 2018-11-20Bibliographically approved
Ahmed, A., Yang, Y., Won Sung, K. & Markendahl, J. (2015). On the Engineering Value of Spectrum in Dense Mobile Network Deployment Scenarios. In: : . Paper presented at 2015 IEEE International Symposium on Dynamic Spectrum Access Networks (DySPAN),29 Sep - 02 Oct 2015,Stockholm, Sweden. IEEE conference proceedings
Open this publication in new window or tab >>On the Engineering Value of Spectrum in Dense Mobile Network Deployment Scenarios
2015 (English)Conference paper, Published paper (Refereed)
Abstract [en]

the continuing growth in the mobile data traffic magnifies the challenges for the design and deployment of scalable high-capacity mobile networks that can meet the future demand at reasonable cost levels. In order to meet the future traffic demand, an operator should invest on both infrastructure, i.e. densification of base stations, and more radio spectrum. Knowing the effectiveness of each element is thus of utmost importance for minimizing the investment cost. In this paper, we study the economic substitutability between spectrum and densification. For this, we measure the engineering value of spectrum, which refers to the potential saving in the total cost of ownership (TCO) as result of acquiring additional spectrum resources. Two countries are considered to represent different market situations: India with dense population and high spectrum price and Sweden with moderate population density and low spectrum fee. Numerical results indicate that additional amount of spectrum substantially relieves the need for densifying radio base stations, particularly for providing high user data rate in dense India. Nonetheless, the engineering value of spectrum is low in India (i.e. spectrum acquisition has less cost benefit) under the high spectrum price of today, whereas spectrum is instrumental in lowering the total cost of ownership in Sweden. Our finding highlights the importance of affordable and sufficient spectrum resources for future mobile broadband provisioning.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2015
Series
IEEE International Symposium on Dynamic Spectrum Access Networks (DySPAN)
Keywords
economic value of spectrum, mobile broadband, MNO, Total Cost of ownership (TCO)
National Category
Telecommunications
Research subject
Information and Communication Technology
Identifiers
urn:nbn:se:kth:diva-185912 (URN)10.1109/DySPAN.2015.7343922 (DOI)000380544200042 ()2-s2.0-84960403130 (Scopus ID)
Conference
2015 IEEE International Symposium on Dynamic Spectrum Access Networks (DySPAN),29 Sep - 02 Oct 2015,Stockholm, Sweden
Projects
METIS-II project
Funder
Wireless@kth
Note

QC 20160429

Available from: 2016-04-28 Created: 2016-04-28 Last updated: 2017-05-10Bibliographically approved
Yang, Y. & Sung, K. W. (2015). Technical rate of substitution of spectrum in future mobile broadband provisioning. In: 2015 IEEE International Symposium on Dynamic Spectrum Access Networks, DySPAN 2015: . Paper presented at IEEE International Symposium on Dynamic Spectrum Access Networks (DySPAN),Stockholm,Sept.29-Oct.2, 2015 (pp. 297-300). IEEE conference proceedings
Open this publication in new window or tab >>Technical rate of substitution of spectrum in future mobile broadband provisioning
2015 (English)In: 2015 IEEE International Symposium on Dynamic Spectrum Access Networks, DySPAN 2015, IEEE conference proceedings, 2015, p. 297-300Conference paper, Published paper (Refereed)
Abstract [en]

Dense deployment of base stations (BSs) and multi-antenna techniques are considered as key enablers for future mobile networks. Meanwhile, spectrum sharing techniques and utilization of higher frequency bands make more bandwidth available. An important question for future system design is which element is more effective than others. In this paper, we introduce the concept of technical rate of substitution (TRS) from microeconomics and study the TRS of spectrum in terms of BS density and antenna number per BS. Numerical results show that TRS becomes higher with increasing user data rate requirement, suggesting that spectrum is the most effective means of provisioning extremely fast mobile broadband.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2015
Keywords
densification, multi-antenna, Spectum, stochastic geometry
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-185918 (URN)10.1109/DySPAN.2015.7343923 (DOI)000380544200043 ()2-s2.0-84960327036 (Scopus ID)9781479974528 (ISBN)
Conference
IEEE International Symposium on Dynamic Spectrum Access Networks (DySPAN),Stockholm,Sept.29-Oct.2, 2015
Note

QC 20160429

Available from: 2016-04-28 Created: 2016-04-28 Last updated: 2018-11-20Bibliographically approved
Yang, Y. & Sung, K. W. (2015). Tradeoff between spectrum and densification for achieving target user throughput. In: IEEE Vehicular Technology Conference: . Paper presented at 81st IEEE Vehicular Technology Conference, VTC Spring 2015, 11 May 2015 through 14 May 2015. IEEE
Open this publication in new window or tab >>Tradeoff between spectrum and densification for achieving target user throughput
2015 (English)In: IEEE Vehicular Technology Conference, IEEE , 2015Conference paper, Published paper (Refereed)
Abstract [en]

Dense deployment which brings small base stations (BS) closer to mobile devices is considered as a promising solution to the booming traffic demand. Meanwhile, the utilization of new frequency bands and spectrum aggregation techniques provide more options for spectrum choice.Whether to increase BS density or to acquire more spectrum is a key strategic question for mobile operators. In this paper, we investigate the relationship between BS density and spectrum with regard to individual user throughput target. Our work takes into account load-dependent interference model and various traffic demands. Numerical results show that densification is more effective in sparse networks than in already dense networks. In sparse networks, doubling BS density results in almost twofold throughput increase. However, in dense networks where BSs outnumber users, more than 10 times of BS density is needed to double user throughput. Meanwhile, spectrum has a linear relationship with user throughput for a given BS density. The impact of traffic types is also discussed. Even with the same area throughput requirement, different combination of user density and individual traffic amount leads to different needs for BS density and spectrum.

Place, publisher, year, edition, pages
IEEE, 2015
Keywords
Densification, Individual user throughput, Spectrum, Frequency bands, Mobile devices, Individual traffic, Interference modeling, Linear relationships, Mobile operators, Numerical results, Spectrum Aggregation, Traffic demands, Throughput
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-175100 (URN)10.1109/VTCSpring.2015.7146138 (DOI)000371404700552 ()2-s2.0-84940399382 (Scopus ID)9781479980888 (ISBN)
Conference
81st IEEE Vehicular Technology Conference, VTC Spring 2015, 11 May 2015 through 14 May 2015
Note

QC 20151211

Available from: 2015-12-11 Created: 2015-10-09 Last updated: 2018-11-20Bibliographically approved
Yang, Y., Sung, K. W., Wosinska, L. & Chen, J. (2014). Hybrid Fiber and Microwave Protection for Mobile Backhauling. Journal of Optical Communications and Networking, 6(10), 869-878
Open this publication in new window or tab >>Hybrid Fiber and Microwave Protection for Mobile Backhauling
2014 (English)In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 6, no 10, p. 869-878Article in journal (Refereed) Published
Abstract [en]

Several studies have shown that optical-fiber-based backhauling offers a future proof solution to handle rapidly increasing traffic in wireless access networks and outperforms other existing backhauling technologies, such as microwave and copper, in terms of capacity, scalability, and sustainability. However, the deployment cost of fiber infrastructure is relatively high and it may be difficult to provide a cost efficient and flexible protection strategy for a fiber backhauling network. Considering that protection is very important to avoid service interruption in a high-capacity mobile backhauling network, in this paper we propose a hybrid fiber and microwave protection scheme for mobile backhauling based on a passive optical network (PON). The proposed reliable architecture is compatible with any wavelength division multiplexing (WDM)based PON, e. g., pure WDM PON and a hybrid time and wavelength division multiplexing (TWDM) PON, offering high flexibility and relatively low deployment cost. The backup for the feeder fiber is provided by dual homing, while the protection of the distribution section can be established via a microwave connection between two base stations in case high reliability performance is required, e. g., for macrocells covering large service areas. We have carried out an extensive assessment of our approach in terms of connection availability, failure impact, complexity, and flexibility in providing resiliency. We also show a comparison with other existing solutions. The evaluation results confirm that our scheme can achieve relatively high flexibility and reliability performance while maintaining low complexity compared with the existing approaches.

Keywords
Hybrid fiber and microwave technology, Mobile backhauling, Passive optical network (PON), Protection scheme
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-155793 (URN)10.1364/JOCN.6.000869 (DOI)000343163300005 ()2-s2.0-84908117074 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme
Note

QC 20150623

Available from: 2014-11-14 Created: 2014-11-13 Last updated: 2017-12-05Bibliographically approved
Yang, Y., Shi, L. & Zander, J. (2013). On the Capacity of Wi-Fi System in TV White Space with Aggregate Interference Constraint. In: Proceedings of the 2013 8th International Conference on Cognitive Radio Oriented Wireless Networks and Communications, CROWNCOM 2013: . Paper presented at 2013 8th International Conference on Cognitive Radio Oriented Wireless Networks and Communications, CROWNCOM 2013; Washington, DC; United States; 8 July 2013 through 10 July 2013 (pp. 123-128). IEEE conference proceedings
Open this publication in new window or tab >>On the Capacity of Wi-Fi System in TV White Space with Aggregate Interference Constraint
2013 (English)In: Proceedings of the 2013 8th International Conference on Cognitive Radio Oriented Wireless Networks and Communications, CROWNCOM 2013, IEEE conference proceedings, 2013, p. 123-128Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, we present a quantitative assessmentof the performance of a Wi-Fi like system in TV white space andcompare it with the traditional Wi-Fi system in the ISM band.Particular emphasis is given to the constraint on the aggregatesecondary interference on TV reception, which is regarded as thepremise of the link throughput analysis that followed. Numericalevaluation is performed over different scenarios where the TVreceive signal strength, number of unoccupied TV channels, userdensity are varied. Our results show that the primary interferenceconstraint has only significant impact on the secondary systemperformance in rural scenario with low TV receive signalstrength. In other cases, where higher transmit power does notguarantee better performance, the capacity of the system islimited by the secondary self-interference or collisions rather thanthe interference constraint. Therefore, efficient TV White Spaceutilization can be achieved by properly setting the secondarytransmit power adaptive to different environments.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2013
Keywords
adjacent channel interference, aggregate interference, geo-location database, secondary spectrum reuse, TV White Space
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-138291 (URN)10.1109/CROWNCom.2013.6636805 (DOI)2-s2.0-84890831659 (Scopus ID)978-147992120-1 (ISBN)
Conference
2013 8th International Conference on Cognitive Radio Oriented Wireless Networks and Communications, CROWNCOM 2013; Washington, DC; United States; 8 July 2013 through 10 July 2013
Note

QC 20140107

Available from: 2013-12-18 Created: 2013-12-18 Last updated: 2014-06-09Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7559-8911

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