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Farias, F., Fiorani, M., Tombaz, S., Mahloo, M., Wosinska, L., Costa, J. C. W. & Monti, P. (2016). Cost- and energy-efficient backhaul options for heterogeneous mobile network deployments. Photonic network communications, 32(3), 422-437
Open this publication in new window or tab >>Cost- and energy-efficient backhaul options for heterogeneous mobile network deployments
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2016 (English)In: Photonic network communications, ISSN 1387-974X, E-ISSN 1572-8188, Vol. 32, no 3, p. 422-437Article in journal (Refereed) Published
Abstract [en]

Heterogeneous networks (HetNets) have the potential to cater for the capacity requirements of mobile broadband services at reduced cost and energy consumption levels. One key aspect in HetNets is the role of the backhaul. More specifically, it is crucial for a mobile operator to understand the impact of specific technological and architectural upgrades in the mobile backhaul network on the capital and operational expenditure (i.e., CAPEX and OPEX). This paper proposes a comprehensive methodology that can be used to analyze the total cost of ownership of a number of backhaul options based on fiber, microwave, and copper technologies. The study considers both a Greenfield and a Brownfield scenario and takes into account the mobile broadband capacity requirements for the time period between years 2015 and 2025. From the results presented in the paper it can be concluded that even though microwave and fiber will be predominately used in the future, the possible migration paths leading to such fiber- and microwave-based backhaul scenarios might be different, depending upon factors such as spectrum and license costs, time to deployment, availability of equipment, and required quality of service levels.

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2016
Keywords
Mobile broadband, Small cells, Heterogeneous networks (HetNet), Backhaul, Total cost of ownership (TCO), Greenfield deployment, Brownfield deployment, Migration strategies
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-199756 (URN)10.1007/s11107-016-0676-6 (DOI)000390023700008 ()2-s2.0-84996559047 (Scopus ID)
Note

QC 20170120

Available from: 2017-01-20 Created: 2017-01-16 Last updated: 2017-08-15Bibliographically approved
Tombaz, S., Han, S.-w., Sung, K. W. & Zander, J. (2014). Energy Efficient Network Deployment with Cell DTX. IEEE Communications Letters, 18(6), 977-980
Open this publication in new window or tab >>Energy Efficient Network Deployment with Cell DTX
2014 (English)In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 18, no 6, p. 977-980Article in journal (Refereed) Published
Abstract [en]

Cell discontinuous transmission (DTX) is a newfeature that enables sleep mode operations at base station (BS)side during the transmission time intervals (TTIs) when thereis no traffic. In this letter, we analyze the maximum achievableenergy saving of the cell DTX. We incorporate the cell DTXwith a clean-slate network deployment, and obtain optimal BSdensity for lowest energy consumption satisfying a certain qualityof service (QoS) requirement considering daily traffic variation.The numerical result indicates that the fast traffic adaptationcapability of cell DTX favors dense network deployment withlightly loaded cells, which brings about considerable improvementin energy saving.

Place, publisher, year, edition, pages
IEEE Communications Society, 2014
Keywords
Energy Efficiency, Cell DTX, Network Deployment, Cell Load, Traffic Profile.
National Category
Communication Systems Telecommunications
Research subject
Information and Communication Technology
Identifiers
urn:nbn:se:kth:diva-144904 (URN)10.1109/LCOMM.2014.2323960 (DOI)000340115200020 ()2-s2.0-84902139351 (Scopus ID)
Projects
5Green, EIT ICT Labs
Funder
Wireless@kth
Note

QC 20150623

Available from: 2014-05-02 Created: 2014-05-02 Last updated: 2017-12-05Bibliographically approved
Fiorani, M., Tombaz, S., Monti, P., Casoni, M. & Wosinska, L. (2014). Green Backhauling for Rural Areas. In: Green Backhauling for Rural Areas: . Paper presented at 18th International Conference on Optical Network Design and Modeling. IEEE
Open this publication in new window or tab >>Green Backhauling for Rural Areas
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2014 (English)In: Green Backhauling for Rural Areas, IEEE , 2014Conference paper, Published paper (Refereed)
Abstract [en]

Providing wireless broadband access to rural and remote areas is becoming a big challenge for wireless operators, mostly because of the need for a cost-effective and low energy consuming mobile backhaul. However, to the best of our knowledge,energy consumption of different options for backhauling of future rural wireless broadband networks has not been studiedyet. Therefore, in this paper we assess the energy consumption of future rural wireless broadband network deployments andbackhaul technologies. In the wireless segment, two deployment strategies are considered, one with macro base station only,and one with small base stations. In the backhaul segment ,two wireless, i.e., microwave and satellite, and one optical fiber based (i.e., long reach passive optical networks) solutions areconsidered. These options are compared in terms of their abilityto satisfy coverage, capacity and QoS requirements of a numberof rural users in the time span that goes from 2010 until 2021. From the presented results it is possible to conclude that wireless backhaul solutions can significantly increase the energy consumption of the access network. In contrast, the long reach PON based backhaul has much higher energy efficiency and inthe long term might be a better choice for wireless operators.

Place, publisher, year, edition, pages
IEEE, 2014
Keywords
Energy Efficiency, Backhaul, Fiber, Microwave, Satellite, Power Consumption, Traffic Model.
National Category
Telecommunications Communication Systems
Research subject
Information and Communication Technology
Identifiers
urn:nbn:se:kth:diva-144906 (URN)2-s2.0-84905443713 (Scopus ID)
Conference
18th International Conference on Optical Network Design and Modeling
Note

QP 2014

Available from: 2014-05-02 Created: 2014-05-02 Last updated: 2017-08-15Bibliographically approved
Tombaz, S., Monti, P., Farias, F., Fiorani, M., Wosinska, L. & Zander, J. (2014). Is backhaul becoming a bottleneck for green wireless access networks?. In: 2014 IEEE International Conference on Communications, ICC 2014: . Paper presented at 2014 1st IEEE International Conference on Communications, ICC 2014; Sydney, NSW; Australia; 10 June 2014 through 14 June 2014 (pp. 4029-4035). IEEE
Open this publication in new window or tab >>Is backhaul becoming a bottleneck for green wireless access networks?
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2014 (English)In: 2014 IEEE International Conference on Communications, ICC 2014, IEEE , 2014, p. 4029-4035Conference paper, Published paper (Refereed)
Abstract [en]

Mobile operators are facing an exponential traffic growth due to the proliferation of portable devices that require a high-capacity connectivity. This, in turn, leads to a tremendous increase of the energy consumption of wireless access networks. A promising solution to this problem is the concept of heterogeneous networks, which is based on the dense deployment of low-cost and low-power base stations, in addition to the traditional macro cells. However, in such a scenario the energy consumed by the backhaul, which aggregates the traffic from each base station towards the metro/core segment, becomes significant and may limit the advantages of heterogeneous network deployments. This paper aims at assessing the impact of backhaul on the energy consumption of wireless access networks, taking into consideration different data traffic requirements (i.e., from todays to 2020 traffic levels). Three backhaul architectures combining different technologies (i.e., copper, fiber, and microwave) are considered. Results show that backhaul can amount to up to 50% of the power consumption of a wireless access network. On the other hand, hybrid backhaul architectures that combines fiber and microwave performs relatively well in scenarios where the wireless network is characterized by a high small-base-stations penetration rate.

Place, publisher, year, edition, pages
IEEE, 2014
Keywords
Backhaul, Energy Efficiency, Fiber, Heterogeneous Networks, Microwave, Power Consumption, Smallcells, Traffic Model, VDSL2
National Category
Communication Systems Telecommunications
Research subject
Information and Communication Technology
Identifiers
urn:nbn:se:kth:diva-144905 (URN)10.1109/ICC.2014.6883951 (DOI)2-s2.0-84907003394 (Scopus ID)9781479920037 (ISBN)
Conference
2014 1st IEEE International Conference on Communications, ICC 2014; Sydney, NSW; Australia; 10 June 2014 through 14 June 2014
Note

QC 20150602

Available from: 2014-05-02 Created: 2014-05-02 Last updated: 2017-08-15Bibliographically approved
Tombaz, S. (2014). On the Design of Energy Efficient Wireless Access Networks. (Doctoral dissertation). Stockholm: KTH Royal Institute of Technology
Open this publication in new window or tab >>On the Design of Energy Efficient Wireless Access Networks
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Wireless access networks today consume 0.5 percent of the global energy. Rapidly growing demand for new services and ubiqutious connectivity, will further increase the energy consumption. This situation imposes a big challenge for mobile operators not only due to soaring cost of energy, but also increasing concern for global warming and sustainable development.

This thesis focuses on the energy efficiency issue at the system level and studies how to incorporate energy-awareness into the design of future wireless access networks. The main contributions have been given in the areas of energy efficiency assessment, architectural and operational solutions, and total cost of investment analysis.

The precise evaluation of energy efficiency is the first essential step to determine optimized solutions where metrics and models constitute the two key elements.We show that maximizing energy efficiency is not always equivalent to minimizing energy consumption which is one of the main reasons behind the presented contradictory and disputable conclusions in the literature. Further we indicate that in order to avoid the debatable directions, energy efficient network design problems should be formulated with well defined coverage and capacity requirements. Moreover, we propose novel backhaul power consumption models considering various technology and architectural options relevant for urban and rural environments and show that backhaul will potentially become a bottleneck in future ultra-high capacity wireless access networks.

Second, we focus on clean-slate network deployment solutions satisfying different quality of service requirements in a more energy efficient manner. We identify that the ratio between idle- and transmit power dependent power consumption of a base station as well as the network capacity requirement are the two key parameters that affect the energy-optimum design.While results show that macro cellular systems are the most energy efficient solution for moderate average traffic density, Hetnet solutions prevail homogeneous deployment due to their ability to increase the capacity with a relatively lower energy consumption and thus enable significant energy savings in medium and high capacity demand regions.

Moreover, we investigate the energy saving potential of short-term energy aware management approach, i.e., cell DTX, taking advantage of low resource utilization in the current networks arising from strict QoS requirements. With the help of developed novel quantitative method, we show that Cell DTX brings striking reduction in energy consumption and further savings are achievable if the networks are designed taking into account the fact that network deployment and operation are closely related.

Finally, we develop a general framework for investigating the main cost elements and for evaluating the viability of energy efficient solutions.We first reveal the strong positive impact of spectrum on both energy and infrastructure cost and further indicate that applying sustainable solutions might also bring total cost reduction, but the viability highly depends on unit cost values as well as the indirect cost benefits of energy efficiency.

Results obtained in this dissertation might provide guidelines for the network designers to achieve future high-capacity and sustainable wireless access networks.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. p. xi, 58
Series
TRITA-ICT-COS, ISSN 1653-6347 ; 1403
Keywords
Energy Efficiency, Wireless Access Networks, Backhaul, Network Deployment, Power Consumption Model, Cell DTX, Cost Analysis
National Category
Communication Systems
Research subject
Information and Communication Technology
Identifiers
urn:nbn:se:kth:diva-144868 (URN)
Public defence
2014-05-23, Sal D, Forum, KTH, Isafjordsgatan 39, Kista, 13:00 (English)
Opponent
Supervisors
Note

QC 20140505

Available from: 2014-05-05 Created: 2014-04-29 Last updated: 2014-05-26Bibliographically approved
Olsson, M., Cavdar, C., Frenger, P., Tombaz, S., Sabella, D. & Jäntti, R. (2013). 5GrEEn: Towards Green 5G Mobile Networks. In: The 9th IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2013): . Paper presented at The 9th IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2013), International Workshop on the Green Optimized Wireless Networks (GROWN 2013), Lyon, France 7th October 2013 (pp. 212-216). IEEE conference proceedings
Open this publication in new window or tab >>5GrEEn: Towards Green 5G Mobile Networks
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2013 (English)In: The 9th IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2013), IEEE conference proceedings, 2013, p. 212-216Conference paper, Published paper (Refereed)
Abstract [en]

In 2020, mobile access networks will experience significant challenges as compared to the situation of today. Traffic volumes are expected to increase 1000 times, and the number of connected devices will be 10-100 times higher than today in a networked society with unconstrained access to information and sharing of data available anywhere and anytime to anyone and anything. One of the big challenges is to provide this 1000-fold capacity increase to billions of devices in an affordable and sustainable way. Low energy consumption is the key to achieve this. This paper takes as starting point the situation of today, and tries to pinpoint important focus areas and potential solutions when designing an energy efficient 5G mobile network architecture. These include system architecture, where a logical separation of data and control planes is seen as a promising solution; network deployment, where (heterogeneous) ultra dense layouts will have a positive effect; radio transmission, where the introduction of massive antenna configurations is identified as an important enabler; and, finally, backhauling solutions that need to be more energy efficient than today. 

Place, publisher, year, edition, pages
IEEE conference proceedings, 2013
Series
International Conference on Wireless and Mobile Computing, Networking and Communications, ISSN 2161-9646
Keywords
5G, green, energy efficiency, mobile network, radio access, system architecture
National Category
Communication Systems Telecommunications
Research subject
SRA - ICT
Identifiers
urn:nbn:se:kth:diva-131942 (URN)10.1109/WiMOB.2013.6673363 (DOI)2-s2.0-84891685877 (Scopus ID)
Conference
The 9th IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2013), International Workshop on the Green Optimized Wireless Networks (GROWN 2013), Lyon, France 7th October 2013
Projects
Towards Green 5G Mobile Networks (5GrEEn)
Funder
Wireless@kth
Note

QC 20131028

Available from: 2013-10-21 Created: 2013-10-21 Last updated: 2014-05-05Bibliographically approved
Tombaz, S., Zheng, Z. & Zander, J. (2013). Energy Efficiency Assessment of Wireless AccessNetworks Utilizing Indoor Base Stations. In: 2013 IEEE 24th International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC): . Paper presented at 2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, PIMRC 2013; London; United Kingdom; 8 September 2013 through 11 September 2013 (pp. 3105-3110). IEEE conference proceedings
Open this publication in new window or tab >>Energy Efficiency Assessment of Wireless AccessNetworks Utilizing Indoor Base Stations
2013 (English)In: 2013 IEEE 24th International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC), IEEE conference proceedings, 2013, p. 3105-3110Conference paper, Published paper (Refereed)
Abstract [en]

Energy efficiency in mobile radio networks has recently gained great interest due to escalating energy cost and environmental concerns. Rapidly growing demand for capacity will require denser and denser networks which further increase the energy consumption. In this regard, the deployment of small cells under macro-cellular umbrella coverage appears a promising solution to cope with the explosive demand in an energy efficient manner. In this paper, we investigate the impact of joint macro-and femtocell deployment on energy efficiency of wireless access networks, based on varying area throughput requirements. We take into account the the co-channel interference, fraction of indoor users, femto base station density and backhaul power consumption. It is shown that utilizing indoor base stations provide significant energy savings compared to traditional macro only network in urban areas with medium and high user demand where the gain increases up to 75 percent as more data traffic is offloaded to femtocells.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2013
Series
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, ISSN 2166-9570
Keywords
Energy Efficiency, Femtocells, Co-channel Deployment, Backhaul, Power Consumption
National Category
Communication Systems
Research subject
SRA - Energy
Identifiers
urn:nbn:se:kth:diva-133930 (URN)10.1109/PIMRC.2013.6666680 (DOI)000346481203035 ()2-s2.0-84893305207 (Scopus ID)978-146736235-1 (ISBN)
Conference
2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, PIMRC 2013; London; United Kingdom; 8 September 2013 through 11 September 2013
Projects
Energy-efficient wireless networking (eWIN)
Funder
Wireless@kth
Note

QC 20131218

Available from: 2013-11-13 Created: 2013-11-13 Last updated: 2015-12-03Bibliographically approved
Tombaz, S., Sung, K. W. & Zander, J. (2012). Energy and Throughput Tradeoff in Temporal Spectrum Sharing. In: 2012 7th International ICST Conference on Cognitive Radio Oriented Wireless Ntworks and Communications, CROWNCOM 2012; Stockholm; 18 June 2012 through 20 June 2012: . Paper presented at 2012 7th International ICST Conference on Cognitive Radio Oriented Wireless Ntworks and Communications, CROWNCOM 2012; Stockholm;18 June 2012 through 20 June 2012 (pp. 265-269). IEEE Computer Society
Open this publication in new window or tab >>Energy and Throughput Tradeoff in Temporal Spectrum Sharing
2012 (English)In: 2012 7th International ICST Conference on Cognitive Radio Oriented Wireless Ntworks and Communications, CROWNCOM 2012; Stockholm; 18 June 2012 through 20 June 2012, IEEE Computer Society, 2012, p. 265-269Conference paper, Published paper (Refereed)
Abstract [en]

It is envisaged that diverse types of short-range wireless systems coexist in shared spectrum in a near future. For low-power systems, throughput and energy efficiency are two design objectives that often conflict with each other. In this paper, we investigate the tradeoff between the throughput and the energy efficiency for a data-hungry but battery-driven low-power network which opportunistically shares radio spectrum in temporal domain. We provide a mathematical framework that determines the optimum frame lengths for the different objectives, and analyze the tradeoff. To this purpose, we propose an energy consumption model that reflects the characteristics of low-power transceivers including power consumption at the receiver side. Numerical results show that the optimum frame length for energy efficiency results in significant loss in throughput, and vice versa. This suggests that the transmission duration of the opportunistic network should be chosen depending on the prime system objective.

Place, publisher, year, edition, pages
IEEE Computer Society, 2012
Keywords
Temporal spectrum sharing, throughput, energy efficiency, sensing, power consumption
National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-107905 (URN)10.4108/icst.crowncom.2012.248433 (DOI)000310377900047 ()2-s2.0-84869384914 (Scopus ID)978-1-936968-55-8 (ISBN)
Conference
2012 7th International ICST Conference on Cognitive Radio Oriented Wireless Ntworks and Communications, CROWNCOM 2012; Stockholm;18 June 2012 through 20 June 2012
Projects
Energy-efficient wireless networking (eWIN)
Funder
ICT - The Next GenerationWireless@kth
Note

QC 20121219

Available from: 2012-12-19 Created: 2012-12-19 Last updated: 2014-05-05Bibliographically approved
Tombaz, S., Sung, K. W. & Zander, J. (2012). Impact of Densification on Energy Efficiency in Wireless Access Networks. In: Globecom Workshops (GC Wkshps), 2012 IEEE: . Paper presented at 2012 IEEE Globecom Workshops, GC Wkshps 2012; Anaheim, CA; United States; 3 December 2012 through 7 December 2012 (pp. 57-62). IEEE
Open this publication in new window or tab >>Impact of Densification on Energy Efficiency in Wireless Access Networks
2012 (English)In: Globecom Workshops (GC Wkshps), 2012 IEEE, IEEE , 2012, p. 57-62Conference paper, Published paper (Refereed)
Abstract [en]

Mobile communication networks alone consume 0.5 percent of the global energy today. Rapidly growing demand for capacity will further increase the energy consumption. Thus, improving energy efficiency has recently gained great interest within the research community not only for environmental awareness but also to lower the operational cost of network operators. Base station deployment strategy is one of the key challenges to be addressed for fulfilling the future capacity demand in an energy efficient manner. In this paper, we investigate the relationship between energy efficiency and densification with regard to network capacity requirement. To this end, we refine the base station power consumption model such that the parameters are determined by the maximum transmit power and develop a simple analytical framework to derive the optimum transmit power that maximizes energy efficiency for a certain capacity target. Our framework takes into account interference, noise and backhaul power consumption. Numerical results show that deployment of smaller cells significantly reduces the base station transmit power, and thus shifts the key elements of energy consumption to idling and backhauling power. Network densification can only be justified when capacity expansion is anticipated.

Place, publisher, year, edition, pages
IEEE, 2012
Series
IEEE Globecom Workshops, ISSN 2166-0069
Keywords
Energy Efficiency, Backhaul, Densification, Network Capacity, Power Consumption
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-104658 (URN)10.1109/GLOCOMW.2012.6477544 (DOI)000320611800011 ()2-s2.0-84875679320 (Scopus ID)978-1-4673-4941-3 (ISBN)
Conference
2012 IEEE Globecom Workshops, GC Wkshps 2012; Anaheim, CA; United States; 3 December 2012 through 7 December 2012
Projects
Energy-efficient wireless networking (eWIN)
Funder
ICT - The Next GenerationWireless@kth
Note

QC 20121109

Available from: 2012-11-08 Created: 2012-11-08 Last updated: 2014-05-05Bibliographically approved
Monti, P., Tombaz, S., Wosinska, L. & Zander, J. (2012). Mobile backhaul in heterogeneous network deployments: Technology options and power consumption. In: 14th International Conference on Transparent Optical Networks: . Paper presented at 14th International Conference on Transparent Optical Networks (ICTON), 2012 (pp. 1-7).
Open this publication in new window or tab >>Mobile backhaul in heterogeneous network deployments: Technology options and power consumption
2012 (English)In: 14th International Conference on Transparent Optical Networks, 2012, p. 1-7Conference paper, Oral presentation only (Refereed)
Abstract [en]

Mobile communication networks account for 0.5% of the global energy consumption, a value that is expected to double within the next five years. For this reason, means of reducing the energy consumption in cellular mobile radio networks has recently gained great interest within the research community. In mobile networks the backhaul contribution to the total power consumption is usually neglected because of its limited impact compared to that of the radio base stations. However, meeting the almost exponential increase in mobile data traffic requires a large number of (mainly small) base stations. This means that backhaul networks will take a significant share of the cost and the energy consumption in future systems. Their actual contribution to the energy consumption will depend on the radio base station deployment scenario as well as on the technology and topology choices for the backhaul itself. This paper presents an initial assessment of the power consumption of two established backhaul technologies, i.e., fiber and microwave. For the microwave case, three backhaul topologies are considered, i.e., tree, ring and star, while for the fiber case only one topology is analysed, i.e., a dedicated point-to-point star. The presented results, assuming off-the-shelf products and based on todays network capacity levels, confirm the importance of considering the backhaul when minimizing the total power consumption in heterogeneous network scenarios. They also show the impact of the basic technology and topology choices of the backhaul for minimizing total power consumption.

Keywords
Green networks, fiber-based backhaul, heterogeneous wireless networks, microwave-based backhaul, mobile backhaul, pico base stations
National Category
Communication Systems
Research subject
SRA - ICT
Identifiers
urn:nbn:se:kth:diva-103700 (URN)10.1109/ICTON.2012.6253839 (DOI)000335346900136 ()2-s2.0-84867002609 (Scopus ID)
Conference
14th International Conference on Transparent Optical Networks (ICTON), 2012
Projects
Energy-efficient wireless networking (eWIN)Wireless@KTH
Funder
ICT - The Next GenerationWireless@kth
Note

QC 20121108

Available from: 2012-10-18 Created: 2012-10-18 Last updated: 2014-10-14Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5016-5044

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