The 5G-XHaul project has just submitted four deliverables. They are still drafts, pending for EU review.
Please read executive summaries below and/or have a look at documents by clicking on each title:
To address the predicted global mobile data traffic increase by a factor of eight between 2015 and 2020 5G-XHaul focuses on developing a converged optical and wireless network solution supported by a flexible and scalable control plane with the aim to form a flexible transport infrastructure. This infrastructure will be able to jointly support the backhaul (BH) and fronthaul (FH) functionalities required to cope with the future challenges imposed by fifth generation (5G) Radio Access Networks (RANs). Recognizing the benefits of the C-RAN architecture and the associated challenges, currently mobile FH solutions are expanded to adopt more effective wireless technologies operating in the Sub-6 GHz and 60 GHz frequency bands enhanced with advanced beam tracking and Multiple-Input Multiple-Output (MIMO) techniques, new versatile Wavelength Division Multiplexing (WDM) optical network platforms as well as novel control and management frameworks that allow service driven customization offering increased granularity, endto-end optimization and guaranteed Quality of Service (QoS). However, to relax the stringent FH requirements of C-RAN architectures, while taking advantage of its pooling and coordination gains, solutions relying on architectures adopting flexible functional splits have been proposed. In the latter case, the introduction of flexible splits allows dividing the processing functions between the CU and the RU. Based on these solutions, a set of processing functions is performed at the RU and the remaining functions are performed centrally. In the majority of the existing solutions, these functions are implemented via closed and specific purpose hardware, which introduces significant installation, operational and administrative costs. To address these issues, the concept of network softwarisation that enables migration from the traditional closed networking model to an open reference platform able to instantiate a variety of network functions, has been recently proposed. In this deliverable, the concept of supporting flexible functional splits is addressed through a combination of small scale servers (cloudlets) embedded in the wireless access and relatively large-scale Data Centres (DCs) placed in the metro network domain. As shown through relevant studies flexible functional splits impose the requirement of fine bandwidth granularity and elastic resource allocation at both the wireless and the optical transport network domains. On the other hand the support of remote processing, demands high bandwidth transport connectivity between the RUs and the remote compute resources at the CU. In response to these observations, 5G-XHaul proposes a converged optical-wireless 5G network infrastructure interconnecting compute resources with fixed and mobile users, to support both operational network (C-RAN and flexible functional split options) and end-user services and defines an innovative heterogeneous network architecture adopting a variety of wireless and optical technologies able to support a wide range of 5G services. In view of this, this deliverable reports on the optical/wireless backhaul and fronthaul 5G-XHaul architecture. In addition, a detailed evaluation of the performance of this architecture is provided through modelling and simulations studies. The main technical innovations of the proposed solution include: i) an overarching architectural framework inspired by the ETSI Network Function Virtualization (NFV) standard and the Software Defined Networking (SDN) open reference architecture that supports jointly BH and FH services and the concept of flexible functional splits, ii) introduction of a novel data plane architecture converging heterogeneous wireless as well as passive and active optical network technologies to support the overarching architecture and its requirements, iii) development of a novel multi-objective optimization (MOP) modelling framework to evaluate the performance of the proposed approach. This includes a service provisioning model used to study a variety of FH and BH options. The overall architecture is evaluated in terms of operational expenditure related with FH services associated with power consumption under strict delay constraints, end-to-end service delay of BH services and monetary capital and operational costs, while relevant trade-offs are identified and discussed.
The goal of this deliverable is to describe how a 5G-XHaul infrastructure provider may deploy the 5G-XHaul network architecture introduced in deliverable D2.2. It is worth noting though that there is no standardised model to deploy a transport network, but instead each operator follows a custom approach constrained by a variety of aspects such as its strategic decisions, legacy technologies, whether it owns fixed infrastructure or not, or its competitive environment. Therefore, this deliverable does not attempt to describe all the possible ways to instantiate the 5G-XHaul architecture, which would depend on each particular case, but instead we select an example scenario, in this case the city of Barcelona, and illustrate how the 5G-XHaul architecture can be deployed in that environment. We believe that this constitutes a representative example that can guide practical 5G-XHaul deployments. Building on the case of Barcelona, we discuss physical deployment aspects, such as the best locations to deploy small cells, how many compute facilities should be scattered throughout the city, or where the control plane functions should be deployed. In addition, we provide a quantitative evaluation of the 5G-XHaul deployment in Barcelona, including the bandwidth required at the different segments of the architecture, i.e. the wireless segment, the WDM-PON access network, and the TSON metro network. We also evaluate control plane aspects, such as the number of 5G-XHaul controllers required for a city like Barcelona, whereby controllers can be deployed as software functions. Finally, we conclude the document with a discussion about how the transport network of the two operators that participate in 5G-XHaul, Telefonica (TID) and COSMOTE (COS), could adopt the principles laid out in the 5GXHaul architecture. The fact that the two considered networks differ significantly in their design, and that different operators have different strategic goals, proves the generality and the impact potential of the 5G-XHaul architecture. The main contribution of this deliverable is to provide a quantitative evaluation of the dimensioning and deployment aspects of the 5G-XHaul architecture in a representative European city. In addition, the work in this deliverable is expected to feed the Techno-Economical analysis that will be carried out as part of WP6.
The next generation of mobile wireless networks, widely known as 5G, represents ambitious challenges for researchers of many fields. The 5G-XHaul project is focused on developing a new architecture capable of providing backhaul and fronthaul services to future 5G networks. 5G-XHaul not only has to cope with increased traffic demands of new access network technologies, but it also has to provide flexibility to accommodate different (and varying) services to one or multiple operators. 5G-XHaul’s data plane achieves this flexibility by means of a converged optical and wireless architecture while, in the control plane, it follows the SDN paradigm. The wireless part of the architecture encompasses both mmWave and Sub-6 GHz radio technologies to build multi-hop wireless mesh islands connecting the access network to the core. These technologies have the potential to offer the needed flexibility to, for example, allow an intelligent control plane to reconfigure the topology and data paths according to diverse criteria (e.g. capacity-oriented, maximize energy savings, react to broken links, etc.), accommodate flows with different QoS requirements (and honour different SLAs), allow multi-tenancy, etc. However, transport nodes participating in the wireless backhaul need to be adapted to the desired architecture in order to unleash said potential. Wireless transport nodes must therefore expose different programmable features to the SDN-based control plane operating in 5G-XHaul. In this document, we define how IEEE 802.11-based Sub-6 GHz transport nodes are integrated within the 5G-XHaul framework, including the design of the node architecture and the programmable capabilities it makes available to the SDN control plane. The document also provides an evaluation of the system-wide benefits obtained when an intelligent control plane is able to orchestrate the defined capabilities. Finally, we propose a definite hardware platform whereupon we implement the 5G-XHaul Sub-6 GHz node and provide initial performance measurements.
5G-XHaul aims at building up an ambitious converged optical and wireless network solution that relies on a flexible infrastructure able to support backhaul (BH) and fronthaul (FH) networks required to cope with the future challenges imposed by 5G radio access networks. One of the key 5G access technologies is massive MIMO, which utilizes hundreds or even thousands of transceivers at a single radio unit to provide very high cell capacities and user throughputs. This technology, however, comes at the price of significantly higher data rate requirements on the FH link between the baseband and the radio unit compared to state-of-the-art radio units with only two or four transceivers. In order to mitigate these requirements 5G-XHaul develops an advanced antenna system for massive MIMO, which features 96 transceivers and digital processing capabilities to support a specific functional split architecture that reduces the FH data rate requirements by a factor of six to twelve, depending on the number of virtual ports employed. In addition, 5G-XHaul develops a 5G base band unit (BBU) prototype platform. Here, the focus is on demonstration and evaluations of signal waveforms with the capability to reduce peak-to-averagepower (PAPR) as well out-of-band (OOB) emissions significantly compared to state-of-the-art OFDM waveforms as used in LTE. The BBU implements generalized frequency division multiplexing (GFDM) as one promising candidate of such a waveform. This report provides an overview of the concept, implementation, and performance of these two 5G-XHaul hardware platforms, i.e., the 5G BBU and the 5G advanced antenna system (AAS). Initial tests and measurements are performed on both platforms. These include OOB performance of the GFDM waveform generated by the BBU and RF performance such as adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) of the AAS. The performance results of both platforms meet regulatory requirements as well as expectations. The implementation activities reported here contribute directly to the 5G-XHaul’s ambition to demonstrate key enabling technologies for flexible and re-configurable transport networks for 5G mobile communications. A brief outline of corresponding demonstration activities as planned is given at the end of the report.
Contact: Jesus Guttierez Teran, Scientist, System Design/Wireless Broadband Communication Systems, IHP, teran@ihp-microelectronics.com
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