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  • 1.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Gong, Yu
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    High Capacity and Energy Efficient Optical Interconnects at Top of the Rack in Datacentres2014Conference paper (Refereed)
  • 2.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Gong, Yu
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Aleksic, Slavisa
    Optical Interconnects at the Top of the Rack for Energy-Efficient Data Centers2015In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 53, no 8, p. 140-148Article in journal (Refereed)
    Abstract [en]

    The growing popularity of cloud and multimedia services is dramatically increasing the traffic volume that each data center needs to handle. This is driving the demand for highly scalable, flexible, and energy-efficient networks inside data centers, in particular for the edge tier, which requires a large number of interconnects and consumes the dominant part of the overall power. Optical fiber communication is widely recognized as the highest energy-and cost-efficient technique to offer ultra-large capacity for telecommunication networks. It has also been considered as a promising transmission technology for future data center applications. Taking into account the characteristics of the traffic generated by the servers, such as locality, multi-cast, dynamicity, and burstiness, the emphasis of the research on data center networks has to be put on architectures that leverage optical transport to the greatest possible extent. However, no feasible solution based on optical switching is available so far for handling the data center traffic at the edge tier. Therefore, apart from conventional optical switching, we investigate a completely different paradigm, passive optical interconnects, and aim to explore the possibility for optical interconnects at the top of the rack. In this article, we present three major types of passive optical interconnects and carry out a performance assessment with respect to the ability to host data center traffic, scalability, optical power budget, complexity of the required interface, cost, and energy consumption. Our results have verified that the investigated passive optical interconnects can achieve a significant reduction of power consumption and maintain cost at a similar level compared to its electronic counterpart. Furthermore, several research directions on passive optical interconnects have been pointed out for future green data centers.

  • 3.
    Cheng, Yuxin
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Lin, Rui
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    POTORI: A Passive Optical Top-of-Rack Interconnect Architecture for Data Centers2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 5, p. 401-411Article in journal (Refereed)
    Abstract [en]

    Several optical interconnect architectures inside data centers (DCs) have been proposed to efficiently handle the rapidly growing traffic demand. However, not many works have tackled the interconnects at top-of-rack (ToR), which have a large impact on the performance of the data center networks (DCNs) and can introduce serious scalability limitations due to their high cost and power consumption. In this paper, we propose a passive optical ToR interconnect architecture (POTORI) to replace the conventional electronic packet switch (EPS) in the access tier of DCNs. In the data plane, POTORI relies on a passive optical coupler to interconnect the servers within the rack and interfaces toward the aggregation/core tiers. The POTORI control plane is based on a centralized rack controller responsible for managing the communications among the servers in the rack. We propose a cycle-based medium access control (MAC) protocol to efficiently manage the exchange of control messages and the data transmission inside the rack. We also introduce and evaluate a dynamic bandwidth allocation algorithm for POTORI, namely largest first (LF). Extensive simulation results show that, with the use of fast tunable optical transceivers, POTORI and the proposed LF strategy are able to achieve an average packet delay below 10 μs under realistic DC traffic scenarios, outperforming conventional EPSs. On the other hand, with slower tunable optical transceivers, a careful configuration of the network parameters (e.g., maximum cycle time of the MAC protocol) is necessary to obtain a good network performance in terms of the average packet delay.

  • 4.
    Cheng, Yuxin
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Centralized Control Plane for Passive Optical Top-of-Rack Interconnects in Data Centers2016In: 2016 IEEE Global Communications Conference, GLOBECOM 2016 - Proceedings, IEEE conference proceedings, 2016, article id 7841655Conference paper (Refereed)
    Abstract [en]

    To efficiently handle the fast growing traffic inside data centers, several optical interconnect architectures have been recently proposed. However, most of them are targeting the aggregation and core tiers of the data center network, while relying on conventional electronic top-of-rack (ToR) switches to connect the servers inside the rack. The electronic ToR switches pose serious limitations on the data center network in terms of high cost and power consumption. To address this problem, we recently proposed a passive optical top-of-rack interconnect architecture, where we focused on the data plane design utilizing simple passive optical components to interconnect the servers within the rack. However, an appropriate control plane tailored for this architecture is needed to be able to analyze the network performance, e.g., packet delay, drop rate, etc., and also obtain a holistic network design for our passive optical top-of-rack interconnect, which we refer to as POTORI. To fill in this gap, this paper proposes the POTORI control plane design which relies on a centralized rack controller to manage the communications inside the rack. To achieve high network performance in POTORI, we also propose a centralized medium access control (MAC) protocol and two dynamic bandwidth allocation (DBA) algorithms, namely Largest First (LF) and Largest First with Void Filling (LFVF). Simulation results show that POTORI achieves packet delays in the order of microseconds and negligible packet loss probability under realistic data center traffic scenarios.

  • 5.
    Cheng, Yuxin
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Reliability Analysis of Interconnects at Edge Tier in Datacenters2015In: 2015 17th International Conference on Transparent Optical Networks (ICTON), Institute of Electrical and Electronics Engineers (IEEE), 2015, article id UNSP We.C3.1Conference paper (Refereed)
    Abstract [en]

    The growing popularity of cloud based applications is drastically increasing the traffic volume that datacenters have to handle. This brings the need for scalable, reliable, and energy-efficient interconnection networks inside the datacenters. Optical communication has been considered as a promising technology for datacenter applications due to its high energy- and cost-efficiency at ultra-high capacity. A typical datacenter interconnection network includes several tiers. Figure 1 shows an example with three tiers: edge, aggregation and core. Due to the large number of active devices on top of the rack (ToR) energy consumption at the edge tier is dominating the overall power consumed by all the switches within the datacenter [1-2]. Several passive optical interconnect approaches [2-4] have been proposed showing that replacing active optical devices by passive ones is possible to significantly reduce both the hardware cost and energy consumption, achieve lower maintenance complexity and offer a sufficient level of scalability. [GRAPHICS] Furthermore, several topologies, e.g., fat-tree [5], Quartz [6], are investigated in order to improve the resiliency and scalability, particularly for large-scale datacenters. However, it should be noted that the redundancy for these proposed topologies is often added in the aggregation and core tiers rather than the edge tier, due to the cost issue. Although passive optical ToR solution by nature could provide better reliability performance than its active counterpart, the intra-rack communication may still need survivability strategies to meet very high connection availability requirement. For instance, the required availability of fault-tolerant datacenter infrastructure (including electrical power supply, storage and distribution facilities) should be higher than 99.995% [7]. Then the expected availability for any connection established within the datacenter needs to be even higher, since the communication system is only a part of the site infrastructure. In this regard, we analyse reliability performance of optical interconnects and identify the key part to be protected. Based on it, we propose some reliable passive optical interconnects for the edge tier of the datacenter interconnection networks. They can achieve ultra-high connection availability for intra-rack communications and adapt to any topology, e.g., fat-tree and Quartz, designed to increase scalability and reliability performance for the overall datacenter network.

  • 6.
    Cheng, Yuxin
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Reliable and Cost Efficient Passive Optical Interconnects for Data Centers2015In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 19, no 11, p. 1913-1916Article in journal (Refereed)
    Abstract [en]

    To address the sustainability, scalability, and reliability problems that data centers are currently facing, we propose three passive optical interconnect (POI) architectures on top of the rack. The evaluation results show that all three architectures offer high reliability performance (connection availability for intra-rack interconnections higher than 99.999%) in a cost-efficient way.

  • 7. Colman-Meixner, C.
    et al.
    Figueiredo, G. B.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tornatore, M.
    Mukherjee, B.
    Resilient cloud network mapping with virtualized BBU placement for cloud-RAN2017In: 2016 IEEE International Conference on Advanced Networks and Telecommunications Systems, ANTS 2016, Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7947790Conference paper (Refereed)
    Abstract [en]

    Cloud Radio Access Network (C-RAN) will improve mobile radio coordination and resource efficiency by allowing baseband processing unit (BBU) functions to be virtualized and centralized, i.e., deployed in a BBU hotel. We consider a BBU hoteling scheme based on the concept of access cloud network (ACN). An ACN consists of virtualized BBUs (vBBUs) placed in metro cloud data centers (metro DCs). A vBBU is connected to a set of remote radio heads (RRHs). ACN resiliency against network and processing failures is critical for C-RAN deployments. Hence, in this study, we propose three protection approaches: 1+1 ACN protection, 1+1 ACN and vBBU protection, and partial ACN protection. Simulation results show that both 1+1 ACN and 1+1 ACN and vBBU protection requires large capacity for backup to provide 100% survivability for singlelink and single-DC failures. As a result, we suggest a partial ACN protection approach which provides degraded services with only 8% additional network resources.

  • 8. Diego Cardoso, D.
    et al.
    Fiorani, Matteo
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Joint planning of small cells and optical transport deployment in heterogeneous mobile networks2014In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2014Conference paper (Refereed)
    Abstract [en]

    We investigate how to reduce the deployment cost of heterogeneous mobile networks by joint dimensioning small cells and optical transport resources. The proposed heuristic is able to save 24% of total network deployment cost.

  • 9. Farias, Fabricio
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Tombaz, Sibel
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Mahloo, Mozhgan
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Costa, Joao C. W. A.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Cost- and energy-efficient backhaul options for heterogeneous mobile network deployments2016In: Photonic network communications, ISSN 1387-974X, E-ISSN 1572-8188, Vol. 32, no 3, p. 422-437Article in journal (Refereed)
    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.

  • 10.
    Fiorani, M.
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Samadi, P.
    Shen, Y.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Bergman, K.
    KTH, School of Information and Communication Technology (ICT).
    Flexible architecture and control strategy for metro-scale networking of geographically distributed data centers2016In: European Conference on Optical Communication, ECOC, Institute of Electrical and Electronics Engineers Inc. , 2016, p. 166-168Conference paper (Refereed)
    Abstract [en]

    This paper proposes a flexible architecture and control strategy to enable adaptive resource allocation in metro-scale inter data center networks. Experimental implementation and numerical evaluations are presented, proving substantial benefits in terms of transmission time and resource usage. 

  • 11.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Aleksic, Slavisa
    Casoni, Maurizio
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Energy-Efficient Elastic Optical Interconnect Architecture for Data Centers2014In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 18, no 9, p. 1531-1534Article in journal (Refereed)
    Abstract [en]

    To address the urgent need for high-capacity, scalable and energy-efficient data center solutions, we propose a novel data center network architecture realized by combining broadcast-and-select approach with elastic channel spacing technology. We demonstrate that the proposed architecture is able to scale efficiently with the number of servers and offers lower energy consumption at a competitive cost compared to the existing solutions.

  • 12.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Optical networks for energy-efficient data centers2014Conference paper (Refereed)
    Abstract [en]

    The growing popularity of cloud and multimedia services is increasing the traffic volume that each datacenter (DC) needs to handle. As a consequence, the serious bottlenecks in DC networks in terms of both capacity and energy consumption need to be addressed. DC networks typically consist of edge tier, aggregation tier and core tier, which interconnect different servers within a DC as well as provide the interfaces to the Internet. Current large-scale DC network architectures are based on the fat-tree three-tiers topology [1] and on electronic switches, which are not able to scale to meet future traffic requirements in a sustainable manner. Reducing the power required by the inter- and intra-rack communication inside DCs through use of optical technology opens a way to solve this problem. However, the current optical switching technologies are not able to support the dynamic DC traffic, and hence, new optical interconnect architectures are needed. Several optical switching architectures have been recently proposed to replace the aggregation and core tiers of current DC networks with a high-capacity optical switch [1][2]. However, the largest amount of energy in current DC networks is consumed in the edge tier by the electronic top-of-the-rack (ToR) switches. Therefore, the optical switching in the aggregation-core tier doesn’t solve the problem. Moreover, the majority of the optical DC network architectures proposed so far can be categorized as optical circuit switching or optical packet switching. Unfortunately, there are certain limitations associated with these optical switching technologies for their application in DC networks. Namely, optical circuit switching architectures are not able handle the bursty and highly variable DC traffic while optical packet switching usually makes use of electronic buffers, which limit scalability and increase energy consumption. To reduce the energy consumption in the edge tier, we propose a novel optical broadcast-and-select - rchitecture at the ToR. In this architecture, each server is equipped with an optical network interface (ONI) and is connected to the other servers in the same rack through a N?2 coupler, where N represents the number of servers in the rack. In addition, in order to provide both fine switching granularity and high scalability, we propose the use of the elastic optical networking paradigm [3]. Consequently, each ONI will be equipped with a bandwidth variable transceiver (BVT), which provides the ability to tune wavelength and change dynamically the number of the occupied spectral slots. In this way, the capacity can be varied from 1 Gb/s to 100 Gb/s and beyond on a per-server level. On the other side, the inter-rack communications are handled by a large singlesided optical core switch. One of the commercially available single-sided switches is fabricated using the beam steering technology [4], where the maximum number of switch ports available so far is 192 and a 500-port matrix is under development. Larger single-sided switches can be realized by combining several stages of smaller switch matrices. The results of a preliminary study show that the proposed architecture is able to significantly reduce the energy consumption with respect to other solutions [1][2].

  • 13.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Skubic, B.
    Martensson, J.
    Valcarenghi, L.
    Castoldi, P.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Challenges for 5G transport networks2014In: 2014 IEEE International Conference on Advanced Networks and Telecommunication Systems, ANTS 2014, IEEE conference proceedings, 2014Conference paper (Refereed)
    Abstract [en]

    5G mobile communications is seen as the enabler for the networked society where connectivity will be available anywhere and anytime to anyone and anything. The details of 5G are the subject to ongoing research and debate, mostly focused on understanding radio technologies that can enable the 5G vision. So far, less work has been dedicated to the challenges that 5G will pose to the transport network. This paper provides a first analysis of the key challenges to 5G transport in terms of capacity, flexibility and costs, for example. Different use cases are discussed as well as technology options and control plane concepts. © 2014 IEEE.

  • 14.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Kungliga Tekniska högskolan.
    Rostami, Ahmad
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Abstraction Models for Optical 5G Transport Networks2016In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 8, no 9, p. 656-665Article in journal (Refereed)
    Abstract [en]

    The orchestration of radio, transport, and cloud resources is a key enabler for efficient service delivery in 5G networks. Orchestration can be achieved with a hierarchical software-defined networking (SDN) control architecture in which a global orchestrator operates above the domain controllers. In such an architecture, the abstraction of resources between the controllers and the orchestrator plays a fundamental role for the system performance. In order to reduce the orchestrator complexity, the controllers should hide as much detail as possible from the orchestrator. On the other hand, the more details are available to the orchestrator the more optimal resource orchestration strategy can be obtained. In order to assess this trade-off, we recently proposed two transport abstraction models, namely big switch (BiS) and virtual link (VL), for centralized radio access networks (C-RANs) with orchestration of radio and transport resources. We observed that VL can provide a more efficient resource orchestration than BiS at the expense of an increased implementation complexity. The contribution of this paper is twofold. We extend the BiS and VL models to make them applicable to any orchestration scenario. Then, we propose a new transport abstraction model, referred to as optical transport transformation (OTT), that aims at achieving efficient resource orchestration with a reduced implementation complexity. We compare the performance of these new abstraction models in a C-RAN use case in which backhaul and fronthaul traffic are carried over a dense wavelength division multiplexing (DWDM) network. Our results prove that in a C-RAN the best choice for the transport abstraction model depends on the availability and the reachability of the radio resources. If radio resources are scarce compared to transport resources, complex transport abstraction models are not needed and a BiS abstraction is the best choice. On the other hand, if radio resources are widely available and reachable, an OTT model guarantees the best overall performance.

  • 15.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Rostami, Ahmad
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Transport Abstraction Models for an SDN-Controlled Centralized RAN2015In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 19, no 8, p. 1406-1409Article in journal (Refereed)
    Abstract [en]

    In a centralized radio access network (C-RAN) scenario the joint coordination of radio (e.g., remote radio units, baseband units) and transport (e.g., optical cross connects) resources can be achieved via software defined networking (SDN) control plane, where a global orchestrator harmonizes the use of resources across all network segments. The more accurate the information about each domain (i.e., the abstraction of wireless and transport resources) is, the better will be the outcome of the orchestration work. This letter presents three transport resources abstraction models along with their corresponding orchestration policies. Their performance are compared showing that there is not a single best abstraction strategy that fits all the cases. If radio resources are scarce compared to transport resources, complex transport abstraction models are not needed. Contrariwise, if enough radio resources are widely available, more detailed abstraction models are required for achieving good network performance, but at the expense of an increased implementation complexity.

  • 16.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Samadi, Payman
    Shen, Yiwen
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Bergman, Keren
    Flexible Network Architecture and Provisioning Strategy for Geographically Distributed Metro Data Centers2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 5, p. 385-392Article in journal (Refereed)
    Abstract [en]

    The fifth generation of mobile networks (5G) is expected to introduce new services with strict end-to-end delay requirements. For this reason, service providers and network operators are increasingly relying on geographically distributed metro data centers (DCs) to bring services closer to end-users and reduce delivery time. The metro DCs frequently exchange data for different purposes, such as backup and load balancing. Some of these data transfers require guaranteed low delays. Meanwhile, efficient use of network resources is necessary to limit the cost of the network infrastructure. To address these issues, in this paper, we propose a converged intra-and inter-DC network architecture and a dynamic provisioning strategy that are able to (i) efficiently support different classes of service, (ii) offer fast data transfers among metro DCs, and (iii) enable efficient utilization of network resources. Simulation results show that the proposed network architecture and provisioning strategy achieve at least two times faster average data transfer between DCs and better network resource utilization compared with conventional solutions. We also present a prototype and an extensive set of experimental results, thus proving the implementation feasibility and effectiveness of the proposed approach.

  • 17.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Skubic, B.
    Mårtensson, J.
    Valcarenghi, L.
    Castoldi, P.
    Wosinska, L.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    On the design of 5G transport networks2015In: Photonic network communications, ISSN 1387-974X, E-ISSN 1572-8188, Vol. 30, no 3, p. 403-415Article in journal (Refereed)
    Abstract [en]

    Future 5G systems will pave the way to a completely new societal paradigm where access to information will be available anywhere, anytime, and to anyone or anything. Most of the ongoing research and debate around 5G systems are focusing on the radio network segment (e.g., how to offer high peak-rates per subscriber, and how to handle a very large number of simultaneously connected devices without compromising on coverage, outage probability, and latency). On the other hand, understanding the impact that 5G systems will have on the transport network (i.e., the segment in charge of the backhaul of radio base stations and/or the fronthaul of remote radio units) is also very important. This paper provides an analysis of the key architectural challenges for the design of a flexible 5G transport infrastructure able to adapt in a cost-efficient way to the plethora of requirements coming from the large number of envisioned future 5G services.

  • 18.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Kungliga Tekniska högskolan.
    Tombaz, S.
    Mårtensson, J.
    Skubic, B.
    Wosinska, L.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Energy performance of C-RAN with 5G-NX radio networks and optical transport2016In: 2016 IEEE International Conference on Communications, ICC 2016, IEEE conference proceedings, 2016Conference paper (Refereed)
    Abstract [en]

    Each mobile network architecture able to meet the traffic requirements of future 5G services comes with its own set of benefits vs. requirements for the radio and the transport segments. This paper focuses on the energy performance of four mobile network architectures, each one with different splitting options for the baseband processing functions. The radio segment under exam is based on a new radio access technology referred to as 5G-NX, while the transport segment is based on wavelength division multiplexing (WDM). The energy consumption of each mobile network architecture is weighted against (i) the benefits for the radio segment as a function of the level of centralization of the baseband processing resources and (ii) the required transport capacity and consequently the power consumption levels needed to accommodate the backhaul, midhaul, and/or fronthaul traffic generated at each base station. Our results show that a fully centralized radio access network (C-RAN) with centralization of all the baseband functions is not a practical approach for 5G mobile networks, while a partially centralized C-RAN architecture in which the physical layer baseband processing is performed at the base station site represents a promising solution.

  • 19.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tombaz, S.
    Mårtensson, J.
    Skubic, Björn
    KTH, School of Information and Communication Technology (ICT).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Modeling energy performance of C-RAN with optical transport in 5G network scenarios2016In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 8, no 11, article id B21Article in journal (Refereed)
    Abstract [en]

    The deployment of new 5G wireless interfaces based on massive multiantenna transmission and beamforming is expected to have a significant impact on the complexity and power consumption of the transport network. This paper analyzes the energy performance of four radio access network (RAN) architectures, each one utilizing a different option for splitting the baseband processing functions. The radio segment is based on Long-Term Evolution (LTE) and 5G radio access technologies. The transport segment is based on optical wavelength division multiplexing, where coherent and direct detection transmissions are considered. The energy consumption of each RAN architecture is weighted against i) the benefits for the radio segment as a function of the level of centralization of the baseband processing functions and ii) the power consumption levels needed to accommodate the capacity generated at each base station. Results show that, with LTE radio interfaces, the energy consumption of the transport network amounts to only a few percent of the overall network power consumption. As a result, fully centralized LTE radio architectures are a viable option, with energy savings of at least 27% compared with conventional distributed architectures. On the other hand, with advanced 5G radio interfaces, centralized architectures, if not carefully designed, might become impractical due to the excessive energy consumption of the transport network (i.e., as a result of the huge capacity to be accommodated). This aspect can be mitigated via a careful joint design of the radio and the transport network (i.e., leveraging on appropriate optical transmission techniques and compromising where needed on the radio network performance).

  • 20.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Tombaz, Sibel
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Farias, Fabricio S.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Monti, Paolo
    Joint Design of Radio and Transport for Green Residential Access Networks2016In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 34, no 4, p. 812-822Article in journal (Refereed)
    Abstract [en]

    d Mobile networks are the largest contributor to the carbon footprint of the telecom sector and their contribution is expected to rapidly increase in the future due to the foreseen traffic growth. Therefore, there is an increasing urgency in the definition of green mobile network deployment strategies. This paper proposes a four-step design and power assessment methodology for mobile networks, taking into consideration both radio and transport segments. A number of mobile network deployment architectures for urban residential areas based on different radio (i.e., macro base station, distributed indoor radio, femto cell) and transport (i.e., microwave, copper, optical fiber) technologies are proposed and evaluated to identify the most energy efficient solution. The results show that with low traffic the conventional macro base station deployment with microwave based backhaul is the best option. However, with higher traffic values heterogeneous networks withmacro base stations and indoor small cells are more energy efficient. The best small cell solution highly depends on the transport network architecture. In particular, our results show that a femto cell based deployment with optical fiber backhaul is the most energy efficient, even if a distributed indoor radio architecture (DRA) deployment with fiber fronthaul is also a competitive approach.

  • 21.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tombaz, Sibel
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Casoni, Maurizio
    University of Modena and Reggio Emilia.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Green Backhauling for Rural Areas2014In: Green Backhauling for Rural Areas, IEEE , 2014Conference 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.

  • 22.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tornatore, M.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Mukherjee, B.
    Optical spatial division multiplexing for ultra-high-capacity modular data centers2016In: 2016 Optical Fiber Communications Conference and Exhibition, OFC 2016, Institute of Electrical and Electronics Engineers (IEEE), 2016Conference paper (Refereed)
    Abstract [en]

    We propose and evaluate four optical interconnect architectures based on spatial division multiplexing for ultra-high capacity modular data centers. It is shown in which way the best option depends on the network load and size.

  • 23.
    Fiorani, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Tornatore, M.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Mukherjee, B.
    Spatial division multiplexing for high capacity optical interconnects in modular data centers2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 2, p. A143-A153, article id 7858118Article in journal (Refereed)
    Abstract [en]

    Modular design has recently emerged as an efficient solution to build large data center (DC) facilities. Modular DCs are based on stand-Alone prefabricated modules (i.e., PODs) that can be easily installed and interconnected. PODs can generate a large amount of traffic and thus require an ultra-high-capacity interconnection network. However, current electronic and optical interconnect architectures applied to modular DCs may experience major scalability problems in terms of high energy consumption and cabling complexity. To address these problems, we investigate five optical interconnect architectures based on spatial division multiplexing (SDM), and for each architecture, we propose a resource allocation strategy. We also present an extensive comparison among the SDM architectures in terms of cost and performance (i.e., blocking probability and throughput), with the objective to find the architecture offering the best trade-off between cost and performance for given DC sizes and traffic load values. Our results demonstrate that, in small modular DCs with low traffic load, an architecture based only on SDM is the best option, while in medium DCs with medium traffic load, an architecture based on coupled SDM and flexgrid wavelength division multiplexing (WDM) with spectral flexibility is the best solution. Finally, for large DCs with high traffic load values, the best trade-off between cost and performance is achieved by an SDM architecture that is based on uncoupled SDM and flexgrid WDM.

  • 24. Khorsandi, B. M.
    et al.
    Raffaelli, C.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Survivable BBU hotel placement in a C-RAN with an optical WDM transport2017In: DRCN 2017 - 13th International Conference on Design of Reliable Communication Networks, Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7993443Conference paper (Refereed)
    Abstract [en]

    In Centralized Radio Access Networks (C-RANs) Baseband Units (BBUs) are decoupled from Remote Radio Units (RRUs) and placed in BBU Hotels. In this way baseband processing resources can be shared among RRUs, providing opportunities for radio coordination and cost/energy savings. However, the failure of a BBU Hotel can affect a large number of RRUs creating severe outages in the radio network. For this reason, the design of a resilient C-RAN is extremely important. This paper focuses on the survivable BBU Hotel placement problem in C-RANs with an optical wavelength division multiplexing (WDM) transport. We first propose an algorithm that jointly decides (i) the placement of a minimum number of BBU Hotels and (ii) solves the Routing and Wavelength Assignment (RWA) problem for the fronthaul connections, ensuring that each RRU is connected to two different BBU Hotels (i.e., one primary and one backup). Then, we present a strategy for maximizing the sharing of backup BBU ports among RRUs, with the aim of reducing the total cost of the C-RAN while guaranteeing uninterrupted service provisioning in case of single BBU Hotel failure. Simulation results show that the proposed strategy helps reducing the overall C-RAN cost. On the other hand, it becomes also evident that the sharing benefits can be maximized only in the presence of a transport network with enough wavelength resources to handle potential bottlenecks that may occur when BBU Hotels are placed quite far from RRUs.

  • 25. Mello, D. A. A.
    et al.
    Barreto, A. N.
    Barbosa, F. A.
    Osorio, C.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Spectrally efficient fronthaul architectures for a cost-effective 5G C-RAN2016In: International Conference on Transparent Optical Networks, IEEE Computer Society, 2016Conference paper (Refereed)
    Abstract [en]

    In 5G wireless systems, centralized RAN (C-RAN) is an architectural choice where the signal waveforms received by Remote Radio Heads (RRH) are transparently forwarded to base band units (BBU), in many cases using an optical fronthaul. Although C-RAN highly simplifies the RRH, which is positive from the operational cost standpoint, much of the system complexity and cost is shifted towards the optical fronthaul. In this paper we show how a cost-effective C-RAN requires a spectrally-efficient optical fronthaul, and discuss the technological options to realize it.

  • 26.
    Muhammad, Ajmal
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Joint Optimization of Resource Allocation for Elastic Optical Intra-Datacenter Network2016In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 20, no 9, p. 1760-1763Article in journal (Refereed)
    Abstract [en]

    The ever-increasing demand for cloud services is posing serious challenges to the scalability of the computing, storing, and networking infrastructure deployed inside the datacenters. To address these challenges, we formulate the integer linear program (ILP) model to minimize the spectrum and the switch port usage by exploiting transparent multi-hop connection capability in elastic optical interconnect architecture for datacenters. The proposed ILP model not only takes into account the networking resources but also the other resources (such as computing and storage) in order to achieve a joint resource optimization in intra-datacenter networks. The optimal results show that substantial savings in both spectrum and switching resources can be achieved by properly tuning the objective function of the proposed optimization strategy.

  • 27. Ohlen, P.
    et al.
    Skubic, B.
    Rostami, A.
    Ghebretensae, Z.
    Martensson, J.
    Wang, K.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Data plane and control architectures for 5G transport networks2015In: European Conference on Optical Communication, ECOC, Institute of Electrical and Electronics Engineers (IEEE), 2015Conference paper (Refereed)
    Abstract [en]

    Next generation 5G mobile system will support the vision of connecting all devices that benefit from a connection. Transport networks need to support the required capacity, latency and flexibility. This paper outlines how 5G transport networks will address these requirements.

  • 28. Raffaelli, C.
    et al.
    Tonini, F.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Optimization of Centralized Radio access networks in indoor areas2016In: International Conference on Transparent Optical Networks, Institute of Electrical and Electronics Engineers (IEEE), 2016Conference paper (Refereed)
    Abstract [en]

    A Centralized Radio Architecture (CRA) allows for the coordination of the physical layer functions of macro and small cells. Efficient techniques can be introduced based on the CRA concept, but deployment cost could potentially increase if CRA networks are not carefully designed. This paper proposes a number of design strategies aimed at cost minimization for CRA networks in residential areas based on heuristics which easily scale with the number of indoor antennas. A few different algorithms, which aim at reducing the overall amount of equipment to cover the area, are described and compared.

  • 29.
    Raza, Muhammad Rehan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Kungliga Tekniska högskolan.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Demonstration of Dynamic Resource Sharing Benefits in an Optical CRAN2016In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 8, no 8, p. 621-632Article in journal (Other academic)
    Abstract [en]

    The next generation of mobilecommunication (i.e., 5G) will bring new challengesfor the transport infrastructure, e.g. in terms offlexibility and capacity. The joint orchestration ofradio and transport resources can help to addresssome of these challenges. One example is thepossibility to reconfigure the use of the transportnetwork resources according to the spatial andtemporal variations of the wireless traffic patterns.Using the concept of dynamic resource sharing, alimited pool of transport resources can be sharedamong a large number of radio base stations (RBSs)thus reducing considerably the overall deploymentcost of the transport infrastructure.This paper proposes a provisioning strategy for acentralized radio access network (C-RAN) with anoptical transport whose wavelength resources can bedynamically shared among multiple RBSs. Theproposed strategy utilizes a hierarchical softwaredefined networking (SDN) control plane where aglobal orchestrator optimizes the usage of radio andtransport resources. The benefits of the proposedstrategy are assessed both by simulation and byexperiment via an optical data plane emulatordeveloped for this purpose. It is shown that thedynamic resource sharing can save up to 31.4% oftransport resources compared to a conventionaldimensioning approach, i.e., based onoverprovisioning of wavelength resources.

  • 30.
    Raza, Muhammad Rehan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Rostami, Ahmad
    Ericsson AB, Kista Sweden.
    Skubic, Björn
    Ericsson AB, Kista Sweden.
    Öhlen, Peter
    Ericsson AB, Kista Sweden.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Dynamic Resource Sharing for C-RANs with Joint Orchestration of Radio and Transport2016In: ECOC 2016 42th European Conference on Optical Communication Proceedings, September 18 - 22, 2016, Düsseldorf, Germany, VDE Verlag GmbH, 2016, p. 1001-1003Conference paper (Refereed)
    Abstract [en]

    We present a resource allocation strategy for centralized radio access network architectures able to adapt to the wireless network capacity requirements. Both simulation and emulation results show that it is possible to reuse up to 33.3% of the transport resources.

  • 31.
    Raza, Muhammad Rehan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Skubic, B
    Ericsson AB, Kista, Sweden.
    Mårtensson, J
    Acreo Swedish ICT AB, Kista, Sweden.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Power and Cost Modeling for 5G Transport Networks2015In: 2015 17th International Conference on Transparent Optical Networks (ICTON), Budapest, Hungary: IEEE Computer Society, 2015, article id 7193533Conference paper (Refereed)
    Abstract [en]

    Optical 5G transport networks are the subject of academic and industrial research aimed at identifying the best architectural and deployment options. In this regard, the optimization of both power consumption and equipment cost is a crucial aspect. This paper analyses a number of architectural options (i.e., all optical vs. intermediate electronic processing, with and without network caching) for optical 5G transport networks, with the objective of understanding which alternatives are the most promising in terms of total power consumption and equipment cost. The analysis presented in the paper shows that 10 Gbps transmission equipment combined with optical switching guarantees the best overall performance. On the other hand, 100 Gbps transmission equipment combined with electronic processing and network caching is also a promising approach, especially in fiber scarce scenarios.

  • 32. Samadi, Payman
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Shen, Yiwen
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Bergman, Keren
    Flexible Architecture and Autonomous Control Plane for Metro-Scale Geographically Distributed Data Centers2017In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 35, no 6, p. 1188-1196Article in journal (Refereed)
    Abstract [en]

    Enterprises and cloud providers are moving away from deployment of large-scale data centers and towards smallto mid-sized data centers because of their lower implementation and maintenance costs. An optical metro network is used to provide connectivity among these data centers. The optical network requires flexibility on bandwidth allocation and various levels of Quality of Service to support the new emerging applications and services including the ones enabled by 5G. As a result, next generation optical metro networks face complex control and management issues that needs to be resolved with automation. We present a converged inter/intra data center network architecture with an autonomous control plane for flexible bandwidth allocation. The architecture supports both single-rate and multi-rate data planes with two types of physical layer connections (Background and Dynamic) that provide connections with strict bandwidth and latency requirements. We demonstrate autonomous bandwidth steering between two data centers on our prototype. Leveraging a simulation platform, we show up to 5x lower transmission times and 25% less spectrum usage compared with the single-rate conventional non-converged networks. This is a significant improvement in the data center network performance and energy efficiency.

  • 33. Samadi, Payman
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT).
    Shen, Yiwen
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Bergman, Keren
    Self-Adaptive, Multi-Rate Optical Network for Geographically Distributed Metro Data Centers2017In: 2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    We propose a self-adaptive, multi-rate converged architecture and control-plane for metro-scale inter-data-center networks, enabling live autonomous bandwidth steering. Experimental and numerical evaluations demonstrate up to 5x and 25% improvements in transmission times and spectrum usage.

  • 34.
    Tombaz, Sibel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Farias, Fabricio
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. Federal University of Para.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Is backhaul becoming a bottleneck for green wireless access networks?2014In: 2014 IEEE International Conference on Communications, ICC 2014, IEEE , 2014, p. 4029-4035Conference 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.

  • 35. Tonini, F.
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Raffaelli, C.
    Monti, P.
    Minimum Cost Deployment of Radio and Transport Resources in Centralized Radio Architectures2016In: 2016 INTERNATIONAL CONFERENCE ON COMPUTING, NETWORKING AND COMMUNICATIONS (ICNC), IEEE Computer Society, 2016Conference paper (Refereed)
    Abstract [en]

    The traffic in mobile access networks is increasing at an exponential rate, with the majority of this traffic being generated indoor. To cope with this trend, heterogeneous network (HetNet) architectures based on the centralized radio architecture (CRA) concept have been recently proposed. A CRA network is able to reach high wireless network performance by centralizing the radio physical layer functions of macro and small cells. On the other hand, a CRA network puts strict latency and capacity requirements on the transport segment, which usually comprises a mixture of fiber- and copper-based infrastructure. These strict constraints may translate into high deployment costs if not carefully addressed. This paper proposes an optimized deployment strategy for CRA networks in residential areas. The objective of the proposed strategy is to contain the total deployment cost by minimizing the number of wireless and transport resources required. We demonstrate that our deployment strategy allows for a significant reduction of the required amount of network components and the overall network cost compared to the existing deployment solutions.

  • 36. Tonini, F.
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Raffaelli, C.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Benefits of joint planning of small cells and fiber backhaul in 5G dense cellular networks2017In: 2017 IEEE International Conference on Communications, ICC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7997216Conference paper (Refereed)
    Abstract [en]

    Base station (BS) densification is increasingly adopted by mobile operators in order to support increasing traffic demand. However, a large number of BSs requires many backhaul connections, which may be very expensive. For this reason, provisioning high speed backhaul connections to BSs in a cost-effective way is challenging, and it is important to efficiently utilize an existing fixed network infrastructure if possible. This paper proposes two optimized infrastructure-aware planning strategies for small cells and fiber backhaul. The first strategy is referred to as joint design (JD) and is based on the joint cost minimization of small cells and fiber backhaul. The JD strategy is compared to a traditional design (TD) solution based on a two-step optimization approach. In the latter a cost-optimal small cells placement is identified first, then the corresponding minimum cost fiber backhaul deployment is determined accordingly. A comparison between these two approaches in dense 5G urban scenarios shows that the relative performance of JD and TD largely depends on the expected traffic demand and on the existing infrastructure. In dense urban areas with the average traffic levels expected for the year 2020 and beyond, JD returns up to 50% lower deployment cost in a greenfield scenario, and up to 70% lower deployment cost in a brownfield scenario. Only in areas with extremely high traffic demand (e.g., open-air festivals and stadiums) JD returns deployment costs very similar to TD.

  • 37.
    Van, Dung Pham
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Resource management for optical interconnects in data centre networks2017In: 2016 IEEE Global Communications Conference, GLOBECOM 2016 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7842226Conference paper (Refereed)
    Abstract [en]

    This paper deals with resource management in data centre networks that feature optical interconnects. It first proposes an optical resource management framework as a platform to develop different solutions for multipoint-to-multipoint optical communication systems with a centralized controller. The paper takes optical intra-rack communications as an example application scenario of the framework and studies the intra-rack scheduling (IRS) problem using a theoretical approach. The problem is mapped into the classical open-shop scheduling problem, in which the optical interfaces are viewed as the jobs and the wavelengths used for communication among the interfaces are viewed as the machines. The IRS problem can therefore be solved by adopting the existing preemptive and/or non-preemptive open-shop scheduling algorithms. In a realistic intra-rack communication scenario with non-negligible network reconfiguration time, it is important to understand whether the preemptive or non-preemptive strategy provides better performance under given traffic conditions and system configurations. To address the question, this paper presents a performance analysis that allows to quantitatively compare the two scheduling strategies in terms of packet delay and potential energy savings obtained from sleep mode implementation. Analytical results reveal that the non-preemptive strategy outperforms the preemptive one for typical configurations used in data centre networks. In addition, the tuning and wake-up times of optical transceivers are shown to be key performance-determining factors. The proposed framework and obtained findings are not limited to the considered intra-rack communication scenario, but can be applied to any centralized optical switching systems featuring multipoint-to-multipoint transmissions with non-negligible reconfiguration time.

  • 38.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Dreier, Dennis
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Silveira, Semida
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    ICT Infrastructure for Smart Cities: Curitiba, Brazil2015Conference paper (Other academic)
  • 39. Yan, Li
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Muhammad, Ajmal
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tornatore, Massimo
    Agrell, Erik
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Network Performance Trade-Off in Optical Spatial Division Multiplexing Data Centers2017In: 2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    We propose close-to-optimal network resource allocation algorithms for modular data centers using optical spatial division multiplexing. A trade-off between the number of established connections and throughput is identified and quantified.

  • 40. Öhlén, P.
    et al.
    Skubic, B.
    Rostami, A.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ghebretensaé, Z.
    Mårtensson, J.
    Wang, K.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Data plane and control architectures for 5G transport networks2016In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 34, no 6, p. 1501-1508, article id 7397818Article in journal (Refereed)
    Abstract [en]

    Next generation 5G mobile system will support the vision of connecting all devices that benefit from a connection, and support a wide range of services. Consequently, 5G transport networks need to provide the required capacity, latency, and flexibility in order to integrate the different technology domains of radio, transport, and cloud. This paper outlines the main challenges, which the 5G transport networks are facing and discusses in more detail data plane, control architectures, and the tradeoff between different network abstraction models.

1 - 40 of 40
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