Energy Saving and Capacity Gain of Micro Sites in Regular LTE Networks: Downlink Traffic Layer Analysis

We study the impact of deployment of low cost, low power micro base stations along with macro base stations on energy consumption and capacity of downlink LTE. We add three important elements to the existing studies: a traffic layer analysis that take both the physical and traffic layer specifications of LTE downlink into account; a threshold-based policy to associate users to base stations; and an allocation scheme to allocate the frequency band to macro and micro sites. We investigate all combinations of these elements through numerical evaluation. We observe that 1. there are important differences between traffic layer and physical layer analysis, 2. threshold-based user association policy improve the capacity of the network by up to 33% without affecting the energy profile of the network, and 3. considerable energy saving and capacity gain can be achieved thought an optimal allocation of the frequency band to macro and micro sites. Finally, we show that up to 46% saving in energy can be achieved by a careful network deployment as compared to the case that no micro sites are deployed in the network

sustainable wireless broadband access to the future internet the earth project

In a world of continuous growth of economies and global population eco-sustainability is of outmost relevance. Especially, mobile broadband networks are facing an exponential growing traffic volume and so the sustainability of these networks comes into focus. The recently completed European funded Seventh Framework Programme (FP7) project EARTH has studied the impact of traffic growth on mobile broadband network energy consumption and carbon footprint, pioneering this field. This chapter summarizes the key insights of EARTH on questions like "How does the exploding traffic impact the sustainability?", "How can energy efficiency be rated and predicted?", "What are the key solutions to improve the energy efficiency and how to efficiently integrate such solutions?" The results are representing the foundation of the maturing scientific engineering discipline of Energy Efficient Wireless Access, targeting the standardisation in IETF and 3GPP, strongly influencing academic research trends, and will soon be reflected in products and deployments of the European telecommunications industry

5G transport network requirements for the next generation fronthaul interface

To meet the requirements of 5G mobile networks, several radio access technologies, such as millimeter wave communications and massive MIMO, are being proposed. In addition, cloud radio access network (C-RAN) architectures are considered instrumental to fully exploit the capabilities of future 5G RANs. However, RAN centralization imposes stringent requirements on the transport network, which today are addressed with purpose-specific and expensive fronthaul links. As the demands on future access networks rise, so will the challenges in the fronthaul and backhaul segments. It is hence of fundamental importance to consider the design of transport networks alongside the definition of future access technologies to avoid the transport becoming a bottleneck. Therefore, we analyze in this work the impact that future RAN technologies will have on the transport network and on the design of the next generation fronthaul interface. To understand the especially important impact of varying user traffic, we utilize measurements from a real-world 4G network and, taking target 5G performance figures into account, extrapolate its statistics to a 5G scenario. With this, we derive both per-cell and aggregated data rate requirements for 5G transport networks. In addition, we show that the effect of statistical multiplexing is an important factor to reduce transport network capacity requirements and costs. Based on our investigations, we provide guidelines for the development of the 5G transport network architecture.Peer ReviewedPostprint (published version

5G infrastructures supporting end-user and operational services:The 5G-XHaul architectural perspective

We propose an optical-wireless 5G infrastructure offering converged fronthauling/backhauling functions to support both operational and end-user cloud services. A layered architectural structure required to efficiently support these services is shown. The data plane performance of the proposed infrastructure is evaluated in terms of energy consumption and service delay through a novel modelling framework. Our modelling results show that the proposed architecture can offer significant energy savings but there is a clear trade-off between overall energy consumption and service delay.Peer ReviewedPostprint (author's final draft

Wireless-optical network convergence: enabling the 5G architecture to support operational and end-user services

© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This article presents a converged 5G network infrastructure and an overarching architecture to jointly support operational network and end-user services, proposed by the EU 5G PPP project 5G-XHaul. The 5G-XHaul infrastructure adopts a common fronthaul/backhaul network solution, deploying a wealth of wireless technologies and a hybrid active/passive optical transport, supporting flexible fronthaul split options. This infrastructure is evaluated through a novel modeling. Numerical results indicate significant energy savings at the expense of increased end-user service delay.Peer ReviewedPostprint (author's final draft

Schemes Abstract

Recently, different schemes have been introduced that improve the bit error rate of single user MISO transmissions through transmit diversity or transmitter-sided beamforming. This is particularly interesting in the downlink of cellular systems, where it is feasible to employ multiple transmit antennas at the base stations, but only few receive antennas at the mobile terminals. In this paper, we observe both classical beamforming schemes, where a beamforming vector is chosen to optimize the SINR at the receiver, and Coherent Alamouti schemes, which extend the classical rate one Alamouti STBC to multiples of two transmit antennas. In both cases, full diversity and an additional gain can be achieved, if a certain extent of channel knowledge is present at the transmitter, which usually has to be supplied by the receiver through feedback. In our work, we evaluate the performance and feedback requirements of the different schemes, while putting a special emphasis on the non-negligible computational complexity required at the receiver to produce optimal feedback. We introduce a novel beamforming scheme that can significantly reduce this complexity while achieving a comparable performance, and provide a comprehensive summary on the choice of an optimal transmission scheme for different applications. 1

Joint Bandwidth Allocation and Small Cell Switching in Heterogeneous Networks

Abstract-One major topic of research into self-organizing network technology is the coordination of SON use cases. Network operators expect a coordinated handling of the parameter and configuration changes submitted to the operating network by closed-loop SON use case implementations. There are currently two basic approaches for SON use case coordination discussed in the literature: A so-called heading or tailing use case external coordination and the combination of separate use cases into one joint algorithm. In this paper, we extend a verified framework to combine mobility load balancing and inter-cell interference coordination use cases, especially for a heterogeneous network environment. Our approach results in a coordinated set of cell range expansion offsets, an efficient bandwidth allocation to support the (enhanced) inter-cell interference coordination use case, and an energy-efficient smart cell switching of the small capacity cells in a heterogeneous networks environment for a varying traffic demand during the course of a day, resulting in significant capacity enhancements while saving energy at the same time

What is the Advantage of Cooperation in Self-Organizing Networks?

Abstract-Self-organizing network (SON) functions can be characterized by their required cooperation between the network elements (NEs). The cooperation among the NEs can include a multitude of possible actions, such as reporting of alarms or coordination of joint parameter modifications at multiple NEs. However, the question for the advantage of cooperation among the NEs in SONs is still an open research topic. By limiting the cooperation between the NEs, the required architectures for utilizing the SON function at hand can be simplified, which in turn can lead to cost savings. In this paper, we investigate the impact of degraded cooperation among the NEs on the SON architecture required and on the performance in a joint capacity and coverage optimization (CCO) use case. For the scenario investigated, we observe that the performance decreases dramatically when decreasing the cooperation among the NEs. However, we can also show that the exchange of information, such as the values of considered key performance indicators (KPIs), among the NEs is more important for an efficient operation than the coordination of the NE's actions. Our results show that, a centralized approach outperforms distributed and localized approaches for the CCO use case investigated