Packet Scheduling Algorithms in LTE/LTE-A cellular Networks: Multi-agent Q-learning Approach

Spectrum utilization is vital for mobile operators. It ensures an efficient use of spectrum bands, especially when obtaining their license is highly expensive. Long Term Evolution (LTE), and LTE-Advanced (LTE-A) spectrum bands license were auctioned by the Federal Communication Commission (FCC) to mobile operators with hundreds of millions of dollars. In the first part of this dissertation, we study, analyze, and compare the QoS performance of QoS-aware/Channel-aware packet scheduling algorithms while using CA over LTE, and LTE-A heterogeneous cellular networks. This included a detailed study of the LTE/LTE-A cellular network and its features, and the modification of an open source LTE simulator in order to perform these QoS performance tests. In the second part of this dissertation, we aim to solve spectrum underutilization by proposing, implementing, and testing two novel multi-agent Q-learning-based packet scheduling algorithms for LTE cellular network. The Collaborative Competitive scheduling algorithm, and the Competitive Competitive scheduling algorithm. These algorithms schedule licensed users over the available radio resources and un-licensed users over spectrum holes. In conclusion, our results show that the spectrum band could be utilized by deploying efficient packet scheduling algorithms for licensed users, and can be further utilized by allowing unlicensed users to be scheduled on spectrum holes whenever they occur

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

Efficient radio resource management in next generation wireless networks

The current decade has witnessed a phenomenal growth in mobile wireless communication networks and subscribers. In 2015, mobile wireless devices and connections were reported to have grown to about 7.9 billion, exceeding human population. The explosive growth in mobile wireless communication network subscribers has created a huge demand for wireless network capacity, ubiquitous wireless network coverage, and enhanced Quality of Service (QoS). These demands have led to several challenging problems for wireless communication networks operators and designers. The Next Generation Wireless Networks (NGWNs) will support high mobility communications, such as communication in high-speed rails. Mobile users in such high mobility environment demand reliable QoS, however, such users are plagued with a poor signal-tonoise ratio, due to the high vehicular penetration loss, increased transmission outage and handover information overhead, leading to poor QoS provisioning for the networks' mobile users. Providing a reliable QoS for high mobility users remains one of the unique challenges for NGWNs. The increased wireless network capacity and coverage of NGWNs means that mobile communication users at the cell-edge should have enhanced network performance. However, due to path loss (path attenuation), interference, and radio background noise, mobile communication users at the cell-edge can experience relatively poor transmission channel qualities and subsequently forced to transmit at a low bit transmission rate, even when the wireless communication networks can support high bit transmission rate. Furthermore, the NGWNs are envisioned to be Heterogeneous Wireless Networks (HWNs). The NGWNs are going to be the integration platform of diverse homogeneous wireless communication networks for a convergent wireless communication network. The HWNs support single and multiple calls (group calls), simultaneously. Decision making is an integral core of radio resource management. One crucial decision making in HWNs is network selection. Network selection addresses the problem of how to select the best available access network for a given network user connection. For the integrated platform of HWNs to be truly seamless and efficient, a robust and stable wireless access network selection algorithm is needed. To meet these challenges for the different mobile wireless communication network users, the NGWNs will have to provide a great leap in wireless network capacity, coverage, QoS, and radio resource utilization. Moving wireless communication networks (mobile hotspots) have been proposed as a solution to providing reliable QoS to high mobility users. In this thesis, an Adaptive Thinning Mobility Aware (ATMA) Call Admission Control (CAC) algorithm for improving the QoS and radio resource utilization of the mobile hotspot networks, which are of critical importance for communicating nodes in moving wireless networks is proposed. The performance of proposed ATMA CAC scheme is investigated and compare it with the traditional CAC scheme. The ATMA scheme exploits the mobility events in the highspeed mobility communication environment and the calls (new and handoff calls) generation pattern to enhance the QoS (new call blocking and handoff call dropping probabilities) of the mobile users. The numbers of new and handoff calls in wireless communication networks are dynamic random processes that can be effectively modeled by the Continuous Furthermore, the NGWNs are envisioned to be Heterogeneous Wireless Networks (HWNs). The NGWNs are going to be the integration platform of diverse homogeneous wireless communication networks for a convergent wireless communication network. The HWNs support single and multiple calls (group calls), simultaneously. Decision making is an integral core of radio resource management. One crucial decision making in HWNs is network selection. Network selection addresses the problem of how to select the best available access network for a given network user connection. For the integrated platform of HWNs to be truly seamless and efficient, a robust and stable wireless access network selection algorithm is needed. To meet these challenges for the different mobile wireless communication network users, the NGWNs will have to provide a great leap in wireless network capacity, coverage, QoS, and radio resource utilization. Moving wireless communication networks (mobile hotspots) have been proposed as a solution to providing reliable QoS to high mobility users. In this thesis, an Adaptive Thinning Mobility Aware (ATMA) Call Admission Control (CAC) algorithm for improving the QoS and radio resource utilization of the mobile hotspot networks, which are of critical importance for communicating nodes in moving wireless networks is proposed

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

Multimedia delivery in the future internet

The term “Networked Media” implies that all kinds of media including text, image, 3D graphics, audio and video are produced, distributed, shared, managed and consumed on-line through various networks, like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked challenges of the Networked Media in the transition to the Future of the Internet. Internet has evolved and changed the way we work and live. End users of the Internet have been confronted with a bewildering range of media, services and applications and of technological innovations concerning media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged that in a near- to mid-term future, the Internet will provide the means to share and distribute (new) multimedia content and services with superior quality and striking flexibility, in a trusted and personalized way, improving citizens’ quality of life, working conditions, edutainment and safety. In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and innovative applications “on the move”, like virtual collaboration environments, personalised services/ media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to contribute towards such a vision. Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6) and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way ahead in the area of Content Aware media delivery platforms

Multiple resource reuse for device-to-device communication in future cellular networks

Aufgrund der stärkeren Verbreitung neuer mobiler Anwendungen, z.B. Autonomes Fahren, automatisierte Prozesssteuerung, intelligente Städte / Wohnen und taktiles Internet, nimmt - die Anzahl und Dichte von Geräten, die drahtlose Verbindungen erfordern, immer weiter zu. Dies erfordert effizientere Verfahren zur Nutzung des verfügbaren Frequenzspektrums für zellulare Netze. Um dieser Herausforderung zu begegnen, wurden Ansätze, wie die gemeinsame Nutzung von Frequenzen, vorgeschlagen, um die gesamte spektrale Effizienz zu verbessern. Die Device-to-Device Kommunikation (D2D) mit paralleler Übertragung zu einem zellularen Netz bietet eine Verbesserung der spektralen Effizienz durch die verstärkte gemeinsame Nutzung des verfügbaren zellularen Spektrums. Mit D2D kommunizieren Geräte in unmittelbarer Nähe direkt miteinander ohne oder mit nur einer minimalen Kontrolle über das Mobilfunknetz. Das 3rd Generation Partnership Project (3GPP) unterstützt durch Standardisierung die Integration von D2D in Mobilfunknetze, um die spektralen Effizienzgewinne bei der gemeinsamen Nutzung von Frequenzen unter Gewährleistung der Quality of Service (QoS) zu realisieren. Die Interferenzen zwischen D2D und zellularen Benutzern müssen jedoch während der gemeinsamen Nutzung des Spektrums kontrolliert werden, um diese Gewinne im Netzwerk zu erhalten. Die vorliegende Arbeit untersucht Lösungen, mit denen das Frequenzspektrum des Mobilfunknetzes mit D2D-Benutzern geteilt werden kann, welche sowohl die spektrale Effizienz maximieren als auch die QoS-Anforderungen aller Benutzer erfüllen (in Bezug auf das Signal-zu-Rausch-plus-Interferenz Verhältnis (SINR)). Die vorliegende Arbeit gliedert sich in zwei Teile: eine analytische und eine algorithmische Studie. Zunächst untersucht die analytische Studie den Ansatz für ein Interferenzmanagement, in welchem mehrere D2D-Benutzer das zellulare Spektrum gemeinsam nutzen. Dabei wird die Zuteilung einer einheitlichen Interferenzleistung (UIP) vorgeschlagen - ein Verfahren, bei dem alle D2D-Benutzer mit gleicher Interferenz an der Basisstation (BS) beitragen. Dieses Schema wird auf ein Szenario einer einzelnen Zelle angewendet, welches sehr positive Ergebnisse bei der Verbesserung der spektralen Effizienz erzielt, obwohl einige D2D-Benutzer ihre SINR-Schwellenwerte nicht erreichen können. Eine wesentliche Erkenntnis aus der analytischen Studie ist, dass eine räumliche Trennung zwischen Benutzern, die das Spektrum gemeinsam nutzen, wichtig ist, um ihre gegenseitige Beeinflussung zu minimieren. Die algorithmische Studie konzentriert sich daher auf die Auswahl geeigneter D2D-Benutzern. Zunächst werden räumliche Auswahlkriterien formuliert mit dem Ziel, mehrere D2D-Benutzer zu identifizieren, die das Spektrum eines bestimmten Mobilfunkbenutzers gemeinsam nutzen können, um die spektrale Effizienz zu maximieren, während alle Benutzer ihre SINR-Schwellenwerte erreichen. Danach werden basierend auf diesen Kriterien zwei Auswahlalgorithmen entwickelt. Der erste Algorithmus wählt opportunistisch D2D-Benutzer aus, die bei bestimmten Auswahlinstanzen die geringste Störung für andere das Spektrum gemeinsam nutzende Benutzer verursachen. Der zweite Algorithmus wählt zufällig alle D2D-Benutzer aus, die räumliche von anderen Benutzern getrennt sind, jedoch das Spektrum gemeinsam nutzen. Beide Algorithmen werden mit sehr positiven Ergebnissen durch Simulationen in einem Szenario einer einzelnen Zelle mit einer unterschiedlichen Anzahl von Benutzern vorgestellt. In einem Szenario mit mehreren Zellen, in welchem die Interferenz zwischen den Zellen die Leistungsfähigkeit beeinträchtigt, werden Verbesserungen an beiden Algorithmen vorgestellt, um die festgelegten Ziele zu erreichen. Diese Verbesserungen passen die Auswahlkriterien an, um: 1) keine D2D-Benutzer mit Zellenkante auszuwählen und 2) die Auswirkungen der gemeinsamen Nutzung des Frequenzspektrums zwischen benachbarten Zellen zu berücksichtigen. Die Arbeit zeigt deutlich, dass mithilfe eines geeigneten Auswahlkriteriums mehrere D2D Nutzer in der Lage sind, die gemeinsame Frequenzressource mit zellularen Nutzern zu teilen mit Erhöhung der gesamten spektralen Effizienz und Beibehaltung der QoS Anforderungen aller Nutzer. Die hierbei erbrachten Erkenntnisse können zusammen mit den vorhandenen Ergebnissen als Ausgangspunkt für weitere akademische Forschung sowie einer praktischen Anwendung dienen.Owing to the further proliferation of new mobile applications, e.g. autonomous driving, automated process control, smart cities/homes, and tactile internet, the number and density of devices requiring wireless connectivity continue to increase. This demands ever more efficient methods for utilizing the available frequency spectrum for cellular networks. To counter this challenge, approaches like spectrum sharing have been proposed as enablers to improve the overall spectral efficiency. Device to device communication (D2D) as an underlaying transmission to the cellular network presents spectral efficiency improvements through the increased sharing of the available cellular spectrum. In D2D, devices in close proximity communicate directly with each other having either minimal or no control from the cellular network. The third generation partnership project (3GPP) supports, through standardization, the integration of D2D within cellular networks in order to realize the spectral efficiency gains during spectrum sharing and user quality of service (QoS) guarantees. However, the interference between D2D and cellular users during spectrum sharing must be controlled to get these gains in the network. This thesis studies the solutions through which the cellular network's frequency spectrum can be shared with D2D users to concurrently maximize the spectral efficiency and achieve all users' QoS requirements (in terms of threshold signal-to-interference-plus-noise ratio (SINR)). The thesis is divided into two parts: an analytical study and an algorithmic study. First, the analytical study evaluates the framework for interference management when several D2D users share the cellular network's spectrum. Therein, uniform interference power (UIP) allocation -- a scheme where all D2D users contribute equal interference at the base station (BS), is proposed. This scheme is applied to a single-cell scenario with very positive results in improving spectral efficiency although some D2D users are unable to achieve their threshold SINRs. The main lesson from the analytical study is that spatial separation between users sharing spectrum is important to minimize their mutual interference. So the algorithmic study focuses on D2D-users selection. First, spatial selection criteria are formulated with the objective of identifying multiple D2D users that can share a given cellular user's spectrum to maximize spectral efficiency while all users achieve their threshold SINRs. Thereafter, based on these criteria, two selection algorithms are developed. The first algorithm opportunistically selects D2D users causing the least interference, at given selection instances, to other users sharing the spectrum. The second algorithm randomly selects any D2D users meeting the minimal required spatial separation from other users sharing the spectrum. Both algorithms are presented with very positive results in simulations that consider a single-cell scenario with varying number of users. In a multi-cell scenario, where the experienced inter-cell interference degrades performance, enhancements to both algorithms are applied to achieve the set objectives. These enhancements adapt the selection criteria to: $1$) not select cell-edge D2D users and $2$) take into account the effects of spectrum sharing between neighbouring cells. The thesis studies clearly showed that, using appropriate selection criteria, multiple D2D users can share a specific cellular user's spectrum resources to improve the network's spectral efficiency and achieve all users' QoS requirements. These findings together with other existing results on D2D spectrum resource reuse can be the starting point for further academic research and practical implementation

Resource allocation for transmit hybrid beamforming in decoupled millimeter wave multiuser-MIMO downlink

This paper presents a study on joint radio resource allocation and hybrid precoding in multicarrier massive multiple-input multiple-output communications for 5G cellular networks. In this paper, we present the resource allocation algorithm to maximize the proportional fairness (PF) spectral efficiency under the per subchannel power and the beamforming rank constraints. Two heuristic algorithms are designed. The proportional fairness hybrid beamforming algorithm provides the transmit precoder with a proportional fair spectral efficiency among users for the desired number of radio-frequency (RF) chains. Then, we transform the number of RF chains or rank constrained optimization problem into convex semidefinite programming (SDP) problem, which can be solved by standard techniques. Inspired by the formulated convex SDP problem, a low-complexity, two-step, PF-relaxed optimization algorithm has been provided for the formulated convex optimization problem. Simulation results show that the proposed suboptimal solution to the relaxed optimization problem is near-optimal for the signal-to-noise ratio SNR <= 10 dB and has a performance gap not greater than 2.33 b/s/Hz within the SNR range 0-25 dB. It also outperforms the maximum throughput and PF-based hybrid beamforming schemes for sum spectral efficiency, individual spectral efficiency, and fairness index

LTE performance evaluation with realistic channel quality indicator feedback

In the context of mobile communications, the availability of new services and mobile applications along with the constant evolution in terminals run up the need of higher data rates. In order to fulfill such expectations, mobile operators are continually optimizing and upgrading their networks. The Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) seems to be the path to follow in a very short term. The objective of this project is to study the behaviour of the radio resource assignment in LTE under realistic conditions. The scheduling is a key process in the functioning of the radio interface. Thus, two types of schedulers can be identified, the opportunistic, where the scheduler considers the state of the radio channel to make the best allocation possible, and the non-opportunistic, where the allocation has no knowledge of the radio channel‘s state. As the opportunistic option adapts to the radio channel conditions it requires the transmission of a certain level of signalling from users informing about how the channel evolves along time. One of the objectives of this project is to evaluate the system performance under different degrees of feedback. To do this, different CQI reporting methods have been programmed and simulated. So, to achieve this objective it is obvious that a second one is necessary: program and simulate in a more realistic way the LTE radio channel. The followed methodology has been fundamentally the programming of different mathematical models and algorithms, as well as its simulation. In concrete, one of the main tasks in this work has been to extent a software platform of the research group Wicomtec to obtain more realistic results through dynamic simulations over a dynamic radio channel