Separation Framework: An Enabler for Cooperative and D2D Communication for Future 5G Networks

Soaring capacity and coverage demands dictate that future cellular networks need to soon migrate towards ultra-dense networks. However, network densification comes with a host of challenges that include compromised energy efficiency, complex interference management, cumbersome mobility management, burdensome signaling overheads and higher backhaul costs. Interestingly, most of the problems, that beleaguer network densification, stem from legacy networks' one common feature i.e., tight coupling between the control and data planes regardless of their degree of heterogeneity and cell density. Consequently, in wake of 5G, control and data planes separation architecture (SARC) has recently been conceived as a promising paradigm that has potential to address most of aforementioned challenges. In this article, we review various proposals that have been presented in literature so far to enable SARC. More specifically, we analyze how and to what degree various SARC proposals address the four main challenges in network densification namely: energy efficiency, system level capacity maximization, interference management and mobility management. We then focus on two salient features of future cellular networks that have not yet been adapted in legacy networks at wide scale and thus remain a hallmark of 5G, i.e., coordinated multipoint (CoMP), and device-to-device (D2D) communications. After providing necessary background on CoMP and D2D, we analyze how SARC can particularly act as a major enabler for CoMP and D2D in context of 5G. This article thus serves as both a tutorial as well as an up to date survey on SARC, CoMP and D2D. Most importantly, the article provides an extensive outlook of challenges and opportunities that lie at the crossroads of these three mutually entangled emerging technologies.Comment: 28 pages, 11 figures, IEEE Communications Surveys & Tutorials 201

Control-data separation architecture for cellular radio access networks: a survey and outlook

Conventional cellular systems are designed to ensure ubiquitous coverage with an always present wireless channel irrespective of the spatial and temporal demand of service. This approach raises several problems due to the tight coupling between network and data access points, as well as the paradigm shift towards data-oriented services, heterogeneous deployments and network densification. A logical separation between control and data planes is seen as a promising solution that could overcome these issues, by providing data services under the umbrella of a coverage layer. This article presents a holistic survey of existing literature on the control-data separation architecture (CDSA) for cellular radio access networks. As a starting point, we discuss the fundamentals, concepts, and general structure of the CDSA. Then, we point out limitations of the conventional architecture in futuristic deployment scenarios. In addition, we present and critically discuss the work that has been done to investigate potential benefits of the CDSA, as well as its technical challenges and enabling technologies. Finally, an overview of standardisation proposals related to this research vision is provided

Will SDN be part of 5G?

For many, this is no longer a valid question and the case is considered settled with SDN/NFV (Software Defined Networking/Network Function Virtualization) providing the inevitable innovation enablers solving many outstanding management issues regarding 5G. However, given the monumental task of softwarization of radio access network (RAN) while 5G is just around the corner and some companies have started unveiling their 5G equipment already, the concern is very realistic that we may only see some point solutions involving SDN technology instead of a fully SDN-enabled RAN. This survey paper identifies all important obstacles in the way and looks at the state of the art of the relevant solutions. This survey is different from the previous surveys on SDN-based RAN as it focuses on the salient problems and discusses solutions proposed within and outside SDN literature. Our main focus is on fronthaul, backward compatibility, supposedly disruptive nature of SDN deployment, business cases and monetization of SDN related upgrades, latency of general purpose processors (GPP), and additional security vulnerabilities, softwarization brings along to the RAN. We have also provided a summary of the architectural developments in SDN-based RAN landscape as not all work can be covered under the focused issues. This paper provides a comprehensive survey on the state of the art of SDN-based RAN and clearly points out the gaps in the technology.Comment: 33 pages, 10 figure

Energy Efficient Resource and Topology Management for Heterogeneous Cellular Networks

This thesis investigates how resource and topology management techniques can be applied to achieve energy efficiency while maintaining acceptable quality of service (QoS) in heterogeneous cellular networks comprising high power macrocells and dense deployment of low power small cells. Partially centralised resource and topology management algorithms involving the sharing of decision making responsibilities regarding resource utilization and activation or deactivation of small cells among macrocells, small cells and a central node are developed. Resource management techniques are proposed to enable mobile users to be served by resources of a few small cells. A topology management scheme is applied to switch off idle small cells and switch on sleeping cells in accordance with traffic load and QoS. Resource management techniques, when combined with the topology management technique, achieve significant energy efficiency. A choice restriction technique that restricts users to resources from only a subset of suitable small cells is proposed to mitigate interference and improve QoS. A good balance between energy efficiency and QoS is achieved through this approach. Furthermore, energy saving under different generations of small cell base stations is investigated to provide insights to guide the design of energy saving strategies and the enhancement of existing ones. Also, an online, adaptive energy efficient joint resource and topology management technique is developed to correct deteriorating QoS conditions automatically by using a novel confidence level strategy to estimate QoS and regulate decision making epochs at the central node. Finally, a novel linear search scheme is applied together with database records of performance metrics to select appropriate resource and topology management policies for different traffic loads. This approach achieves better balance between QoS and energy efficiency than previous schemes proposed in the literature

Energy Savings in Heterogeneous Networks with Clustered Small Cell Deployments

Abstract-Ultra dense small cell deployments will play a critical role in addressing future capacity requirements in dense urban outdoor and indoor environments such as train stations and shopping malls. Effective interference and energy management schemes will be needed to make such deployments technically and economically viable. In this paper, we demonstrate the benefits of a database-aided energy savings scheme for clustered small cell deployments. System-level simulations demonstrate that the proposed scheme can yield energy savings of up to 30% even when the network is heavily utilized, and offer throughput gains of up to 25% in case few users are present in the network, with respect to a conventional small cell deployment without the energy savings feature

Energy efficient mobile video streaming using mobility

Undeniably the support of data services over the wireless Internet is becoming increasingly challenging with the plethora of different characteristic requirements of each service type. Evidently, about half of the data traffic shifted across the Internet to date consists of multimedia content such as video clips or music files that necessitate stringent real-time constraints in playback and for which increasing volumes of data should be shifted with the introduction of higher quality content. This work recasts the problem of multimedia content delivery in the mobile Internet. We propose an optimization framework with the major tenet being that real-time playback constraints can be satisfied while at the same time enabling controlled delay tolerance in packet transmission by capitalizing on pre-fetching and data buffering. More specifically two strategies are proposed amenable for real time implementation that utilize the inherent delay tolerance of popular applications based on different flavors of HTTP streaming. The proposed mechanisms have the potential of achieving many-fold energy efficiency gains at no cost on the perceived user experience

Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems. Task 5: Unsteady counterrotation ducted propfan analysis. Computer program user's manual

The primary objective of this study was the development of a time-marching three-dimensional Euler/Navier-Stokes aerodynamic analysis to predict steady and unsteady compressible transonic flows about ducted and unducted propfan propulsion systems employing multiple blade rows. The computer codes resulting from this study are referred to as ADPAC-AOACR (Advanced Ducted Propfan Analysis Codes-Angle of Attack Coupled Row). This report is intended to serve as a computer program user's manual for the ADPAC-AOACR codes developed under Task 5 of NASA Contract NAS3-25270, Unsteady Counterrotating Ducted Propfan Analysis. The ADPAC-AOACR program is based on a flexible multiple blocked grid discretization scheme permitting coupled 2-D/3-D mesh block solutions with application to a wide variety of geometries. For convenience, several standard mesh block structures are described for turbomachinery applications. Aerodynamic calculations are based on a four-stage Runge-Kutta time-marching finite volume solution technique with added numerical dissipation. Steady flow predictions are accelerated by a multigrid procedure. Numerical calculations are compared with experimental data for several test cases to demonstrate the utility of this approach for predicting the aerodynamics of modern turbomachinery configurations employing multiple blade rows

Energy saving in a 5G separation architecture under different power model assumptions

In this paper, a framework is developed to study the impact of different power model assumptions on energy saving in a 5G separation architecture comprising high power Base Stations (BSs) responsible for coverage, and low power, small cell BSs handling data transmission. Starting with a linear power model function, the achievable energy saving are derived over short timescales by operating small cell BSs in low power states rather than higher power states (termed Low Power State Saving (LPSS) gains) for single and multiple BS scenarios. It is shown how energy saving varies with different power model assumptions over long timescales in accordance with short timescale LPSS. Simulation results show that energy saving in the separation architecture varies across the six power models examined as a function of model-specific significant LPSS state changes. Furthermore, it is shown that if the architecture is based on existing small cell BSs modelled by state-of-the-art (SotA) power models, energy saving will be mainly dependent on sleep state operation. Whereas, if it is based on future BSs modelled by visionary power models, both sleep and idle state operations provide energy saving gains. Moreover, with future BSs, energy saving of up to 42% is achievable when idle state overhead is considered, while a higher saving is possible otherwise

D4.3 Final Report on Network-Level Solutions

Research activities in METIS reported in this document focus on proposing solutions to the network-level challenges of future wireless communication networks. Thereby, a large variety of scenarios is considered and a set of technical concepts is proposed to serve the needs envisioned for the 2020 and beyond. This document provides the final findings on several network-level aspects and groups of solutions that are considered essential for designing future 5G solutions. Specifically, it elaborates on: -Interference management and resource allocation schemes -Mobility management and robustness enhancements -Context aware approaches -D2D and V2X mechanisms -Technology components focused on clustering -Dynamic reconfiguration enablers These novel network-level technology concepts are evaluated against requirements defined by METIS for future 5G systems. Moreover, functional enablers which can support the solutions mentioned aboveare proposed. We find that the network level solutions and technology components developed during the course of METIS complement the lower layer technology components and thereby effectively contribute to meeting 5G requirements and targets.Aydin, O.; Valentin, S.; Ren, Z.; Botsov, M.; Lakshmana, TR.; Sui, Y.; Sun, W.... (2015). D4.3 Final Report on Network-Level Solutions. http://hdl.handle.net/10251/7675