Caching-Aided Collaborative D2D Operation for Predictive Data Dissemination in Industrial IoT

Industrial automation deployments constitute challenging environments where moving IoT machines may produce high-definition video and other heavy sensor data during surveying and inspection operations. Transporting massive contents to the edge network infrastructure and then eventually to the remote human operator requires reliable and high-rate radio links supported by intelligent data caching and delivery mechanisms. In this work, we address the challenges of contents dissemination in characteristic factory automation scenarios by proposing to engage moving industrial machines as device-to-device (D2D) caching helpers. With the goal to improve reliability of high-rate millimeter-wave (mmWave) data connections, we introduce the alternative contents dissemination modes and then construct a novel mobility-aware methodology that helps develop predictive mode selection strategies based on the anticipated radio link conditions. We also conduct a thorough system-level evaluation of representative data dissemination strategies to confirm the benefits of predictive solutions that employ D2D-enabled collaborative caching at the wireless edge to lower contents delivery latency and improve data acquisition reliability

Dense Moving Fog for Intelligent IoT: Key Challenges and Opportunities

As the ratification of 5G New Radio technology is being completed, enabling network architectures are expected to undertake a matching effort. Conventional cloud and edge computing paradigms may thus become insufficient in supporting the increasingly stringent operating requirements of \emph{intelligent~Internet-of-Things (IoT) devices} that can move unpredictably and at high speeds. Complementing these, the concept of fog emerges to deploy cooperative cloud-like functions in the immediate vicinity of various moving devices, such as connected and autonomous vehicles, on the road and in the air. Envisioning gradual evolution of these infrastructures toward the increasingly denser geographical distribution of fog functionality, we in this work put forward the vision of dense moving fog for intelligent IoT applications. To this aim, we review the recent powerful enablers, outline the main challenges and opportunities, and corroborate the performance benefits of collaborative dense fog operation in a characteristic use case featuring a connected fleet of autonomous vehicles.Comment: 7 pages, 5 figures, 1 table. The work has been accepted for publication in IEEE Communications Magazine, 2019. Copyright may be transferred without notice, after which this version may no longer be accessibl

Enabling High Throughput and Reliable Low Latency Communication over Vehicular Mobility in Next-Generation Cellular Networks

The fifth-generation (5G) networks and beyond need paradigm shifts to realize the exponentially increasing demands of next-generation services for high throughputs, low latencies, and reliable communication under various mobility scenarios. However, these promising features have critical gaps that need to be filled before they can be fully implemented for mobile applications in complex environments like smart cities. Although the sub-6 GHz bands can provide reliable and larger coverage, they cannot provide high data rates with low latencies due to a scarcity of spectrum available in these bands. Millimeter wave (mmWave) communication is a key enabler for a significant increase in the performance of these networks due to the availability of large bands of spectrum. However, the extremely limited transmission range of mmWave frequencies leads to poor reliability, especially for mobility scenarios. In this work, we present and evaluate the solutions in three key areas for achieving high throughput along with reliable low latency connection, especially for mobility scenarios in next-generation cellular networks. To enable the 5G networks to meet the demanding requirements of cellular networks, we look into (1) multi-connectivity for enhancing the performance of next-generation cellular networks, (2) designing a reliable network using multi-connectivity, and (3) developing a multilink scheme with efficient radio resource management. Despite the technological advances made in the design and evolution of 5G networks, emerging services impose stringent requirements which have not been fully met by 5G networks so far. The work in this dissertation aims to explore the challenges of future networks and address the needs in the three areas listed above. The results of the study open opportunities to resolve real-world 5G network issues. As 5G networks need to fulfill the rising performance demands of upcoming applications and industry verticals, we first study and evaluate multi-connectivity, which involves simultaneous connectivity with multiple radio access technologies or multiple bands, as a key enabler in improving the performance of the 5G networks. 5G networks are designed to have several small cells operating in the mmWave frequency range using ultra-dense networks (UDN) deployments to provide continuous coverage. But, such deployments not only face challenges in terms of frequent handovers, higher latency, lower reliability, and higher interference levels but also in terms of increasing complexity and cost of deployment, unbalanced load distributions, and power requirements. To address the challenges in high density base station deployments, we study and evaluate novel deployment strategies using multi-connectivity. In NR-NR Dual Connectivity (NR-DC), the user equipment (UE) is connected simultaneously to two gNBs, with one acting as the master node and the other as the secondary node to improve the performance of the 5G system. The master node operating at the sub-6 GHz bands provides high reliability, and the secondary node using the high bandwidth mmWave bands provides the high throughputs expected of 5G networks. This deployment also improves the latency as it decreases the number of handovers and link establishments. Thus, in this dissertation, we propose and evaluate novel 5G deployments with multi-connectivity, which can be used to ensure that these 5G networks are able to meet the demanding requirements of future services. The 5G networks also need to support ultra-reliable low latency communication, which refers to using the network for mission-critical communication that requires high reliability along with low latency. However, technological advancements so far have not been able to fully meet all these requirements. Thus, in this work, we design a reliable 5G network using multi-connectivity, which can simultaneously support high throughputs along with ultra-reliable low latency communication. Deployments using mmWave bands are highly susceptible to channel fluctuations and blockages. Thus, it is critical to consider new techniques and approaches that address these needs and can be implemented practically. In this work, we propose and implement a novel approach using packet duplication and its optimization in an NR-DC system to improve the performance of the system. In an NR-DC deployment with packet duplication, multiple instances of a packet are generated and transmitted simultaneously over different uncorrelated channels between the UE and the base stations, which decreases the packet failure probability. We also propose enhancements to the packet duplication feature for efficient radio resource utilization by looking into the distance of the UE from the base station, the velocity of the UE, and the received signal strength indicator (RSSI) levels. The proposed system improves the performance in terms of throughput, latency, and reliability under varying mobility scenarios. Finally, the 5G networks need to meet the increasing demands of uplink data traffic for applications such as autonomous driving, IoT applications, live video, etc. However, the uplink performance is lower compared to the downlink, and hence, it is critical for 5G to improve uplink performance. Thus, there are open research questions on what should be the network architecture with efficient radio resource utilization to meet the stringent requirements for mobility scenarios. In this work, we propose a novel uplink scheme where the UE performs only a single transmission on a common channel, and every base station that can receive this signal would accept and process it. This technique increases the probability of successful transmission and hence, increases the reliability of the network. It also removes the need to perform frequent handovers and allows high mobility with reduced latency. In this work, we propose and evaluate novel approaches for improving the performance of next-generation networks, which will be a key enabler for future applications. The proposed 5G techniques are shown to significantly improve the throughput, latency, and reliability simultaneously and are able to fulfill the stringent requirements of future services. Our work focuses on developing novel solutions for addressing the challenges involved in building next-generation cellular networks. In the future, we plan to further develop our system for real-world city-scale deployments

Non-Terrestrial Networks in the 6G Era: Challenges and Opportunities

Many organizations recognize non-terrestrial networks (NTNs) as a key component to provide cost-effective and high-capacity connectivity in future 6th generation (6G) wireless networks. Despite this premise, there are still many questions to be answered for proper network design, including those associated to latency and coverage constraints. In this paper, after reviewing research activities on NTNs, we present the characteristics and enabling technologies of NTNs in the 6G landscape and shed light on the challenges in the field that are still open for future research. As a case study, we evaluate the performance of an NTN scenario in which satellites use millimeter wave (mmWave) frequencies to provide access connectivity to on-the-ground mobile terminals as a function of different networking configurations.Comment: 8 pages, 4 figures, 2 tables, submitted for publication to the IEE

5G Radio Access above 6 GHz

Designing and developing a millimetre-wave(mmWave) based mobile Radio Access Technology (RAT) in the 6-100 GHz frequency range is a fundamental component in the standardization of the new 5G radio interface, recently kicked off by 3GPP. Such component, herein called the new mmWave RAT, will not only enable extreme mobile broadband (eMBB) services,but also support UHD/3D streaming, offer immersive applications and ultra-responsive cloud services to provide an outstanding Quality of Experience (QoE) to the mobile users. The main objective of this paper is to develop the network architectural elements and functions that will enable tight integration of mmWave technology into the overall 5G radio access network (RAN). A broad range of topics addressing mobile architecture and network functionalities will be covered-starting with the architectural facets of network slicing, multiconnectivity and cells clustering, to more functional elements of initial access, mobility, radio resource management (RRM) and self-backhauling. The intention of the concepts presented here is to lay foundation for future studies towards the first commercial implementation of the mmWave RAT above 6 GHz.Comment: 7 pages, 5 figure

초고밀도밀리미터웨이브셀룰러네트워크에서이중연결기반핸드오버기법

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 전기·정보공학부, 2019. 2. 박세웅최성현심병효.밀리미터 웨이브를 사용하는 초고밀도 셀룰러 네트워크에서 이동하는 단말은 기존의 네트워크보다 더 많은 핸드 오버를 경험할 것이며, 이는 서비스 중단 시간의 증가와 그로 인한 성능저하를 야기할 것이다. 이런 문제점을 해결하기 위한 솔루 션으로서 다중연결성은 밀리미터 웨이브의 통신 범위를 향상시키고 링크를 보다 견고하게 할 수 있다는 점에서 현재 많이 각광 받고 있는 기법 중 하나이다. 본 논 문에서는 한 개의 단말이 기존의 LTE 셀과의 연결을 유지하면서 두 개의 밀리미터 웨이브 셀과 동시에 연결하는 새로운 네트워크 구조를 제안하며, 이러한 연결성에 의존하는 단말의 이동성을 보장하며 핸드오버의 수를 감소시키기 위하여 이중연결 기반 핸드오버 기법을 제시하였다. 또한 논문에서는 제시한 이중연결기법 기반의 핸드오버 기법과 기존의 단일 연결 기반의 핸드오버 기법을 ns-3 시뮬레이션을 통 해 구현하고 비교하였다. 시뮬레이션 결과는 제안 된 기법이 핸드 오버 비율, 전송 실패율 및 전송 지연 시간을 크게 감소시킨다는 것을 보여주었다. 따라서 본 논문은 이중 연결 기반 핸드 오버 기법이 네트워크의 부담을 줄여주고 더 안정적인 전송을 보장하며 보다 나은 서비스 품질을 제공 할 것이라고 주장한다.Mobile UEs in ultra-dense millimeter-wave cellular networks will experience handover events more frequently than in conventional networks, which will cause increased service interruption time and performance degradation. To resolve this, leveraging multi-connectivity becomes a promising solution in that it can improve the coverage of millimeter-wave communications and support link robustness. In this paper, we propose a dual-connection based handover scheme for mobile UEs in an environment where they are connected simultaneously with two millimeter-wave cells to overcome frequent handover problems, keeping a legacy LTE connection. We compare our dual-connection based scheme with a conventional single-connection based one through ns-3 simulation. The simulation results show that the proposed scheme significantly reduces handover rate, transmission failure ratio and delay. Therefore, we argue that the dual-connection based handover scheme will decrease network controlling overheads, guarantee more reliable transmission and provide better quality-of-service.1 Introduction 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Related Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 Contributions and Outline . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Background and System Model 5 2.1 LTE-MmWave Dual Connectivity and Small Cell Handover . . . . . . 5 2.2 Network Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Channel and Propagation Model . . . . . . . . . . . . . . . . . . . . 8 3 Secondary Cell Handover Design for Multi-Connectivity 9 3.1 MmWave-MmWave Dual Connectivity . . . . . . . . . . . . . . . . . 9 3.2 Secondary Cell Handover Scheme . . . . . . . . . . . . . . . . . . . 11 4 Implementation and Performance Evaluation 15 4.1 ns-3 Simulator Implementation . . . . . . . . . . . . . . . . . . . . . 15 4.2 Simulation Setting and Scenario . . . . . . . . . . . . . . . . . . . . 16 4.3 Simulation Results and Discussion . . . . . . . . . . . . . . . . . . . 18 4.3.1 File download completion time . . . . . . . . . . . . . . . . 18 4.3.2 Radio resource usage in user-plane . . . . . . . . . . . . . . . 20 4.3.3 Handover rate and file download failure ratio . . . . . . . . . 20 4.3.4 TCP performance . . . . . . . . . . . . . . . . . . . . . . . . 23 5 Conclusion 25Maste

Enhanced Mobile Networking using Multi-connectivity and Packet Duplication in Next-Generation Cellular Networks

Modern cellular communication systems need to handle an enormous number of users and large amounts of data, including both users as well as system-oriented data. 5G is the fifth-generation mobile network and a new global wireless standard that follows 4G/LTE networks. The uptake of 5G is expected to be faster than any previous cellular generation, with high expectations of its future impact on the global economy. The next-generation 5G networks are designed to be flexible enough to adapt to modern use cases and be highly modular such that operators would have the flexibility to provide selective features based on user demand that could be implemented without investment in additional infrastructure. Thus, the underlying cellular network that is capable of delivering these expectations must be able to handle high data rates with low latency and ultra-reliability to fulfill these growing needs. Communication in the sub-6 GHz range cannot provide high throughputs due to the scarcity of spectrum in these bands. Using frequencies in FR2 or millimeter wave (mmWave) range for communication can provide large data rates and cover densely populated areas, but only over short distances as they are susceptible to blockages. This is why dense deployments of mmWave base stations are being considered to achieve very high data rates. But, such architectures lack the reliability needed to support many V2X applications, especially under mobility scenarios. As we have discussed earlier, 5G and beyond 5G networks must also account for UE\u27s mobility as they are expected to maintain their level of performance under different mobility scenarios and perform better than traditional networks. Although 5G technology has developed significantly in recent years, there still exists a critical gap in understanding how all these technologies would perform under mobility. There is a need to analyze and identify issues that arise with mobility and come up with solutions to overcome these hurdles without compromising the performance of these networks. Multi-connectivity (MC) refers to simultaneous connectivity with multiple radio access technologies or bands and potentially represents an important solution for the ongoing 5G deployments towards improving their performance. To address the network issues that come with mobility and fill that gap, this dissertation investigates the impact of multi-connectivity on next-generation networks from three distinct perspectives, 1) mobility enhancement using multi-connectivity in 5G networks, 2) improving reliability in mobility scenarios using multi-Connectivity with packet duplication, and 3) single grant multiple uplink scheme for performance improvement in mobility scenarios. The traditional macro-cell architecture of cellular networks that cover large geographical areas will struggle to deliver the dense coverage, low latency, and high bandwidth required by some 5G applications. Thus, 5G networks must utilize ultra-dense deployment of access points operating at higher mmWave frequency bands. But, for such dense networks, user mobility could be particularly challenging as it would reduce network efficiency and user-perceived service quality due to frequent handoffs. Multi-connectivity is seen as a key enabler in improving the performance of these next-generation networks. It enhances the system performance by providing multiple simultaneous links between the user equipment (UE) and the base stations (BS) for data transfer. Also, it eliminates the time needed to deal with frequent handoffs, link establishment, etc. Balancing the trade-offs among handoff rate, service delay, and achievable coverage/data rate in heterogeneous, dense, and diverse 5G cellular networks is, therefore, an open challenge. Hence, in this dissertation, we analyze how mobility impacts the performance of current Ultra-dense mmWave network (UDN) architecture in a city environment and discuss improvements for reducing the impact of mobility to meet 5G specifications using multi-connectivity. Current handover protocols, by design, suffer from interruption even if they are successful and, at the same time, carry the risk of failures during execution. The next-generation wireless networks, like 5G New Radio, introduce even stricter requirements that cannot be fulfilled with the traditional hard handover concept. Another expectation from these services is extreme reliability that will not tolerate any mobility-related failures. Thus, in this dissertation, we explore a novel technique using packet duplication and evaluate its performance under various mobility scenarios. We study how packet duplication can be used to meet the stringent reliability and latency requirements of modern cellular networks as data packets are duplicated and transmitted concurrently over two independent links. The idea is to generate multiple instances (duplicates) of a packet and transmit them simultaneously over different uncorrelated channels with the aim of reducing the packet failure probability. We also propose enhancements to the packet duplication feature to improve radio resource utilization. The wide variety of use cases in the 5G greatly differs from the use cases considered during the design of third-generation (3G) and fourth-generation (4G) long-term evolution (LTE) networks. Applications like autonomous driving, IoT applications, live video, etc., are much more uplink intensive as compared to traditional applications. However, the uplink performance is often, by design, lower than the downlink; hence, 5G must improve uplink performance. Hence, to meet the expected performance levels, there is a need to explore flexible network architectures for 5G networks. In this work, we propose a novel uplink scheme where the UE performs only a single transmission on a common channel, and every base station that can receive this signal would accept and process it. In our proposed architecture, a UE is connected to multiple mmWave capable distributed units (DUs), which are connected to a single gNB-central unit. In an ultra-dense deployment with multiple mmWave base stations around the UE, this removes the need to perform frequent handovers and allows high mobility with reduced latency. We develop and evaluate the performance of such a system for high throughput and reliable low latency communication under various mobility scenarios. To study the impact of mobility on next-generation networks, this work develops and systematically analyzes the performance of the 5G networks under mobility. We also look into the effect of increasing the number of users being served on the network. As a result, these studies are intended to understand better the network requirements for handling mobility and network load with multi-connectivity. This dissertation aims to achieve clarity and also proposes solutions for resolving these real-world network mobility issues