Interference mitigation in D2D communication underlaying LTE-A network

The mobile data traffic has risen exponentially in recent days due to the emergence of data intensive applications, such as online gaming and video sharing. It is driving the telecommunication industry as well as the research community to come up with new paradigms that will support such high data rate requirements within the existing wireless access network, in an efficient and effective manner. To respond to this challenge, device-to-device (D2D) communication in cellular networks is viewed as a promising solution, which is expected to operate, either within the coverage area of the existing eNB and under the same cellular spectrum (in-band) or separate spectrum (out-band). D2D provides the opportunity for users located in close proximity of each other to communicate directly, without traversing data traffic through the eNB. It results in several transmission gains, such as improved throughput, energy gain, hop gain, and reuse gain. However, integration of D2D communication in cellular systems at the same time introduces new technical challenges that need to be addressed. Containment of the interference among D2D nodes and cellular users is one of the major problems. D2D transmission radiates in all directions, generating undesirable interference to primary cellular users and other D2D users sharing the same radio resources resulting in severe performance degradation. Efficient interference mitigation schemes are a principal requirement in order to optimize the system performance. This paper presents a comprehensive review of the existing interference mitigation schemes present in the open literature. Based on the subjective and objective analysis of the work available to date, it is also envisaged that adopting a multi-antenna beamforming mechanism with power control, such that the transmit power is maximized toward the direction of the intended D2D receiver node and limited in all other directions will minimize the interference in the network. This could maximize the sum throughput and hence, guarantees the reliability of both the D2D and cellular connections

Multi-cell interference management in In-band D2D communication under LTE-A network

Device-to-Device (D2D) communication is an active research area. As a part of this active research area, Device-to-Device (D2D) communication is largely exploited in Out-band non-cellular technologies, such as, Bluetooth or Wi-Fi network. However, it has not been fully incorporated into existing cellular networks. Interference management is the main challenge of this technology as it generates both intra and inter-cell interference resulting in severe network performance degradation. eNodeBs with high transmit power usually affects D2D user equipments (UEs) with high interference. It usually incurs severe interference to the cellular UEs and to the base station (eNB). The scenario becomes more critical in case of multi-cell environment, which is the main research focus in this paper. In order to encourage and increase frequent use of D2D communications, some changes in the network configuration are required for today’s networking scenario. Flexible multi-cell D2D communication is required to reduce the network load. Interference management techniques are necessary in parallel to make the communication smooth, efficient and effective.This paper reviews multi-cell interference in In-Band D2D communications and investigates interference mitigation techniques in scenarios where two or more similar or different devices under same eNB or from two different eNBs can be connected as a D2D pair without compromising user experience and quality of service standard. These issues cannot be guaranteed by the current applications operated on unlicensed frequency band. The research also addresses the following related issues: mode selection, resource allocation (both for cellular and D2D environment), power control (both for eNB and D2D pair), and flexible frequency allocation techniques. The research aims to look at other issues, such as, achieving high SINR, improved system capacity, better throughput and transmission rate

Interference mitigation scheme by antenna selection in device-to-device communication underlaying cellular networks

In this paper, we investigate an interference mitigation scheme by antenna selection in device-to- device (D2D) communication underlaying downlink cellular networks. We first present the closed-form expression of the system achievable rate and its asymptotic behaviors at high signal-to-noise ratio (SNR) and the large antenna number scenarios. It is shown that the high SNR approximation increases with more antennas and higher ratio between the transmit SNR at the BS and the D2D transmitter. In addition, a tight approximation is derived for the rate and we reveal two thresholds for both the distance of the D2D link and the transmit SNR at the BS above which the underlaid D2D communication will degrade the system rate. We then particularize on the small cell setting where all users are closely located. In the small cell scenario, we show that the relationship between the distance of the D2D transmitting link and that of the D2D interfering link to the cellular user determines whether the D2D communication can enhance the system achievable rate. Numerical results are provided to verify these results

Review on Radio Resource Allocation Optimization in LTE/LTE-Advanced using Game Theory

Recently, there has been a growing trend toward ap-plying game theory (GT) to various engineering fields in order to solve optimization problems with different competing entities/con-tributors/players. Researches in the fourth generation (4G) wireless network field also exploited this advanced theory to overcome long term evolution (LTE) challenges such as resource allocation, which is one of the most important research topics. In fact, an efficient de-sign of resource allocation schemes is the key to higher performance. However, the standard does not specify the optimization approach to execute the radio resource management and therefore it was left open for studies. This paper presents a survey of the existing game theory based solution for 4G-LTE radio resource allocation problem and its optimization

LTE 기반 기기간 통신 성능 향상 연구

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2016. 2. 최성현.Recently, Device-to-Device (D2D) communication has attracted much attention as an emerging solution to cope with heavy cellular traffic caused by the proliferation of mobile devices such as smartphones and tablet PCs along with the increased demands for high data rate services. D2D communication is a promising technique which is introduced to one of the technology in Fifth Generation (5G) mobile network. In this scenario, allowing User Equipments (UEs) to reuse cellular resources can boost up the network performance in terms of the system capacity. In addition, reduced number of hops and shorter communication distance via direct communication between proximity UEs implies reduced energy consumption and communication delay. Moreover, D2D communications can help offload cellular traffic and avoid congestion in cellular network. This dissertation dealt with various aspects of problems under D2D network. For performance enhancement, various schemes and algorithms for D2D discovery and communication are proposed and evaluated via simulation. First of all, we investigate the interference problem occurring during D2D discovery. Every D2D-UE (D-UE) chooses the discovery resource randomly. Therefore, if the same resource is selected by more than one D-UE, mutual interference by collision is inevitable. Moreover, the collided D-UEs can not recognize the collision event in distributed D2D network. To reduce such mutual interference, interference mitigation technique is necessary. This study proposes two schemes to improve the discovery performance by alleviating the mutual interference. Since the proposed schemes are considered to operate in distributed manner, additional signaling or resources are not needed. In addition, performance evaluation of the proposed schemes and algorithm are conducted by incorporating in recent specification. Secondly, this study proposes the D2D discovery and link setup protocol model working in an LTE network. In addition, propose discovery synchronization, beacon resource and energy efficient RRC IDLE state discovery. These proposed model and discovery design in LTE-based is the first study in academia. Even though, the demand for D2D communication has increased, energy consumption is a growing concern as well. A device has to support both cellular and D2D communication, meaning that additional energy is required. Due to the energy concerns, we comparatively analyze the performance of the D2D discovery and link setup in RRC CONNECTED and RRC IDLE states. The performance analysis is conducted by utilizing the real measurement results with commercialized LTE smartphones. Lastly, we design a spatial reuse scheme which is well-known as one of the advantages in proximity D2D communication. The spatial reuse scheme is allowed to reuse one resource by sharing multiple transmitters. However, sharing the spectrum is carefully allowed due to the generating interference mutually. Especially, when two (or more than) devices reuse in proximity. This study investigate the spatial reuse problem under D2D multicast transmission and solve it with distributed manner. Moreover, this study proposes novel resource reusing schemes by multiple transmitters to increase spectrum efficiency. The performance evaluation of the proposed schemes are conducted by incorporating in recent specification, thus the simulation results demonstrate that proposed schemes outperform the baseline scheme.Chapter 1 Introduction 1 1.1 Device-to-Device (D2D) Network 2 1.1.1 D2D Discovery 2 1.1.2 D2D Communication 3 1.2 Overview of Existing Approaches 4 1.2.1 LTE in 3GPP Standard 4 1.2.2 D2D in 3GPP Standard 4 1.2.3 Approaches for D2D Communication 5 1.2.4 Approaches for D2D Discovery 6 1.2.5 Approaches for D2D Spatial Reuse 6 1.3 Main Contributions 7 1.3.1 Interference Mitigation 7 1.3.2 Discovery Protocol Design 8 1.3.3 Spatial Reuse Operation 8 1.4 Organization of the Dissertation 9 Chapter 2 Interference Mitigation for D2D Discovery 10 2.1 Introduction 10 2.2 Background 11 2.2.1 Resource Selection 11 2.2.2 Resource Collision 13 2.2.3 Motivation 14 2.3 System Model 15 2.3.1 D2D System 15 2.3.2 Criteria of Discovery Success 16 2.4 Problem Formulation 17 2.5 Power Control Scheme 18 2.5.1 Power Control Performance 18 2.5.2 Proposed Power Control Algorithm 19 2.6 Collision Resolution Scheme 22 2.6.1 Beacon Design 22 2.6.2 Collision Resolution Scheme 23 2.7 Performance Evaluation 25 2.8 Summary 27 Chapter 3 Protocol Design for D2D Discovery 31 3.1 Introduction 31 3.2 Background 32 3.2.1 Radio Resource Control (RRC) 32 3.2.2 Discontinuous Reception (DRX) 33 3.2.3 Motivation 34 3.3 System Model 35 3.3.1 D2D Beacon 35 3.3.2 D2D Discovery 36 3.3.3 Synchronization 36 3.3.4 D2D Link Setup 38 3.4 Numerical Analysis 39 3.4.1 Average Power Model 39 3.4.2 Base Power Model 40 3.4.3 D2D Link Setup Delay 41 3.5 Performance Evaluation 42 3.6 Summary 42 Chapter 4 Spatial Reuse for D2D Communication 46 4.1 Introduction 46 4.2 Background 48 4.2.1 D2D Communication 48 4.2.2 D2D Group Communication 49 4.2.3 Motivation 51 4.3 Problem Statement 53 4.3.1 Criteria of Successful D2D link 53 4.3.2 Spatial Reuse Interference 54 4.4 Proposed Spatial Reuse Scheme 55 4.4.1 Range-Based Approach 55 4.4.2 Spatial Reuse Scenario 56 4.4.3 Upper Bound and Lower Bound . 58 4.5 Spatial Reuse Operation 60 4.5.1 Spatial Reuse Procedure 60 4.5.2 Spatial Reuse Grant 61 4.6 SR with Multiple Transmitters 63 4.6.1 PS-SR Scheme 64 4.6.2 P-SR Scheme 65 4.7 Performance Evaluation 67 4.8 Comparison of PS-SR and P-SR Schemes 72 4.8.1 Overhead Comparison 72 4.9 Summary 74 Chapter 5 Conclusion 75 5.1 Summary 75 5.2 Future Work 77 Bibliography 79 Abstract (In Korean) 87Docto

Advanced Technologies for Device-to-device Communications Underlaying Cellular Networks

The past few years have seen a major change in cellular networks, as explosive growth in data demands requires more and more network capacity and backhaul capability. New wireless technologies have been proposed to tackle these challenges. One of the emerging technologies is device-to-device (D2D) communications. It enables two cellular user equip- ment (UEs) in proximity to communicate with each other directly reusing cellular radio resources. In this case, D2D is able to of oad data traf c from central base stations (BSs) and signi cantly improve the spectrum ef ciency of a cellular network, and thus is one of the key technologies for the next generation cellular systems. Radio resource management (RRM) for D2D communications and how to effectively exploit the potential bene ts of D2D are two paramount challenges to D2D communications underlaying cellular networks. In this thesis, we focus on four problems related to these two challenges. In Chapter 2, we utilise the mixed integer non-linear programming (MINLP) to model and solve the RRM optimisation problems for D2D communications. Firstly we consider the RRM optimisation problem for D2D communications underlaying the single carrier frequency division multiple access (SC-FDMA) system and devise a heuristic sub- optimal solution to it. Then we propose an optimised RRM mechanism for multi-hop D2D communications with network coding (NC). NC has been proven as an ef cient technique to improve the throughput of ad-hoc networks and thus we apply it to multi-hop D2D communications. We devise an optimal solution to the RRM optimisation problem for multi-hop D2D communications with NC. In Chapter 3, we investigate how the location of the D2D transmitter in a cell may affect the RRM mechanism and the performance of D2D communications. We propose two optimised location-based RRM mechanisms for D2D, which maximise the throughput and the energy ef ciency of D2D, respectively. We show that, by considering the location information of the D2D transmitter, the MINLP problem of RRM for D2D communications can be transformed into a convex optimisation problem, which can be ef ciently solved by the method of Lagrangian multipliers. In Chapter 4, we propose a D2D-based P2P le sharing system, which is called Iunius. The Iunius system features: 1) a wireless P2P protocol based on Bittorrent protocol in the application layer; 2) a simple centralised routing mechanism for multi-hop D2D communications; 3) an interference cancellation technique for conventional cellular (CC) uplink communications; and 4) a radio resource management scheme to mitigate the interference between CC and D2D communications that share the cellular uplink radio resources while maximising the throughput of D2D communications. We show that with the properly designed application layer protocol and the optimised RRM for D2D communications, Iunius can signi cantly improve the quality of experience (QoE) of users and of oad local traf c from the base station. In Chapter 5, we combine LTE-unlicensed with D2D communications. We utilise LTE-unlicensed to enable the operation of D2D in unlicensed bands. We show that not only can this improve the throughput of D2D communications, but also allow D2D to work in the cell central area, which normally regarded as a “forbidden area” for D2D in existing works. We achieve these results mainly through numerical optimisation and simulations. We utilise a wide range of numerical optimisation theories in our works. Instead of utilising the general numerical optimisation algorithms to solve the optimisation problems, we modify them to be suitable for the speci c problems, thereby reducing the computational complexity. Finally, we evaluate our proposed algorithms and systems through sophisticated numer- ical simulations. We have developed a complete system-level simulation framework for D2D communications and we open-source it in Github: https://github.com/mathwuyue/py- wireless-sys-sim

Sum Rate Maximization and Consistency in D2D Communication Based on ACO and Game Theory

Cellular network is the most popular network setup among today’s wireless communication systems. The primary resource in a cellular system is the spectrum for communication, and owing to the rising number of cellular users, the spectrum that is currently accessible from different service providers is depleting quickly. The resource or channel allocation is the most hindering task in cellular networks. Many efforts have been taken by many researchers to allocate the resources properly in order to increase the channel utilization and it is found that one effective method for reusing the channels inside a cell is device to device (D2D) communication. D2D communication was first developed in order to achieve the fundamental goals of fast data rates, widespread coverage with little latency, energy efficiency, and low per-information transmission costs. The dynamic behaviour of this network set-up again increases the risk of different types of interferences, which is another issue faced by the researchers. In this paper an effort is taken to understand and solve various aspects of channel allocation and Cellular networks have incorporated interference management in D2D communication especially. The two major issues of allocation of resource and management of interference in D2D communication is addressed here. This paper considers the meta heuristic algorithm namely Ant Colony Optimization (ACO) for resource allocation issue and interference management. The sum rate maximization is achieved through Game theory along with the concept of resource exchange in turn to increase the consistency of D2D communication setup. The results demonstrate that our algorithm can significantly increase the sum rate of D2D pairs when compared to other algorithms suggested by related works

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

Device-to-Device Communication in 5G Cellular Networks

Owing to the unprecedented and continuous growth in the number of connected users and networked devices, the next-generation 5G cellular networks are envisaged to support enormous number of simultaneously connected users and devices with access to numerous services and applications by providing networks with highly improved data rate, higher capacity, lower end-to-end latency, improved spectral efficiency, at lower power consumption. D2D communication underlaying cellular networks has been proposed as one of the key components of the 5G technology as a means of providing efficient spectrum reuse for improved spectral efficiency and take advantage of proximity between devices for reduced latency, improved user throughput, and reduced power consumption. Although D2D communication underlaying cellular networks promises lots of potentials, unlike the conventional cellular network architecture, there are new design issues and technical challenges that must be addressed for proper implementation of the technology. These include new device discovery procedures, physical layer architecture and radio resource management schemes. This thesis explores the potentials of D2D communication as an underlay to 5G cellular networks and focuses on efficient interference management solutions through mode selection, resource allocation and power control schemes. In this work, a joint admission control, resource allocation, and power control scheme was implemented for D2D communication underlaying 5G cellular networks. The performance of the system was evaluated, and comparisons were made with similar schemes.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format