Providing ubiquitous connectivity to diverse device types is the key challenge for 5G and beyond 5G (B5G). Unmanned aerial vehicles (UAVs) are expected to be an important component of the upcoming wireless networks that can potentially facilitate wireless broadcast and support high rate transmissions. Compared to the communications with fixed infrastructure, UAV has salient attributes, such as flexible deployment, strong line-of-sight (LoS) connection links, and additional design degrees of freedom with the controlled mobility. In this paper, a comprehensive survey on UAV communication towards 5G/B5G wireless networks is presented. We first briefly introduce essential background and the space-air-ground integrated networks, as well as discuss related research challenges faced by the emerging integrated network architecture. We then provide an exhaustive review of various 5G techniques based on UAV platforms, which we categorize by different domains including physical layer, network layer, and joint communication, computing and caching. In addition, a great number of open research problems are outlined and identified as possible future research directions.

UAV Communications for 5G and Beyond: Recent Advances and Future Trends

This article discusses the technologies for realizing highly efficient data migration and backup for big data applications in elastic optical inter-data-center (inter-DC) networks. We first describe the impacts of big data applications on underlying network infrastructure and introduce the concept of flexible-grid elastic optical inter-DC networks. Then we model the data migration in such networks as dynamic anycast and propose several efficient algorithms. Joint resource defragmentation is also discussed to further improve network performance. For efficient data backup, we leverage a mutual backup model and investigate how to avoid the prolonged negative impacts on DCs’ normal operation by minimizing the DC backup window.

Highly efficient data migration and backup for big data applications in elastic optical inter-data-center networks

Big data applications in operations/supply-chain management

The emerging software defined networking (SDN) paradigm separates the data plane from the control plane and centralizes network control in an SDN controller. Applications interact with controllers to implement network services, such as network transport with quality of service. SDN facilitates the virtualization of network functions so that multiple virtual networks can operate over a given installed physical network infrastructure. Due to the specific characteristics of optical (photonic) communication components and the high optical transmission capacities, SDN-based optical networking poses particular challenges, but holds also great potential. In this article, we comprehensively survey studies that examine the SDN paradigm in optical networks; in brief, we survey the area of software defined optical networks (SDONs). We mainly organize the SDON studies into studies focused on the infrastructure layer, the control layer, and the application layer. Moreover, we cover SDON studies focused on network virtualization, as well as SDON studies focused on the orchestration of multilayer and multidomain networking. Based on the survey, we identify open challenges for SDONs and outline future directions.

Software Defined Optical Networks (SDONs): A Comprehensive Survey

Network function virtualization (NFV) is a promising technology to decouple the network functions from dedicated hardware elements, leading to the significant cost reduction in network service provisioning. As more and more users are trying to access their services wherever and whenever, we expect the NFV-related service function chains (SFCs) to be dynamic and adaptive, i.e., they can be readjusted to adapt to the service requests’ dynamics for better user experience. In this paper, we study how to optimize SFC deployment and readjustment in the dynamic situation. Specifically, we try to jointly optimize the deployment of new users’ SFCs and the readjustment of in-service users’ SFCs while considering the trade-off between resource consumption and operational overhead. We first formulate an integer linear programming (ILP) model to solve the problem exactly. Then, to reduce the time complexity, we design a column generation (CG) model for the optimization. Simulation results show that the proposed CG-based algorithm can approximate the performance of the ILP and outperform an existing benchmark in terms of the profit from service provisioning.

On Dynamic Service Function Chain Deployment and Readjustment

Empowered by the optical orthogonal frequency-division multiplexing (O-OFDM) technology, flexible online service provisioning can be realized with dynamic routing, modulation, and spectrum assignment (RMSA). In this paper, we propose several online service provisioning algorithms that incorporate dynamic RMSA with a hybrid single-/multi-path routing (HSMR) scheme. We investigate two types of HSMR schemes, namely HSMR using online path computation (HSMR-OPC) and HSMR using fixed path sets (HSMR-FPS). Moreover, for HSMR-FPS, we analyze several path selection policies to optimize the design. We evaluate the proposed algorithms with numerical simulations using a Poisson traffic model and two mesh network topologies. The simulation results have demonstrated that the proposed HSMR schemes can effectively reduce the bandwidth blocking probability (BBP) of dynamic RMSA, as compared to two benchmark algorithms that use single-path routing and split spectrum. Our simulation results suggest that HSMR-OPC can achieve the lowest BBP among all HSMR schemes. This is attributed to the fact that HSMR-OPC optimizes routing paths for each request on the fly with considerations of both bandwidth utilizations and lengths of links. Our simulation results also indicate that the HSMR-FPS scheme that use the largest slots-over-square-of-hops first path-selection policy obtains the lowest BBP among all HSMR-FPS schemes. We then investigate the proposed algorithms' impacts on other network performance metrics, including network throughput and network bandwidth fragmentation ratio. To the best of our knowledge, this is the first attempt to consider dynamic RMSA based on both online path computation and offline path computation with various path selection policies for multipath provisioning in O-OFDM networks.

/pdf/dynamic-service-provisioning-in-elastic-optical-networks-5cgwrzictg.pdf

Dynamic Service Provisioning in Elastic Optical Networks With Hybrid Single-/Multi-Path Routing

Advances in wireless communications are empowering the emerging Internet-of-Things (IoT) applications and services with billions of connected devices Mobile-edge computing (MEC) has been proposed to reduce the round-trip delay of these applications as IoT devices may have limited computing resources and the resource-rich mobile cloud may be far away On the other aspect, unmanned aerial vehicles (UAVs) may potentially be employed to improve the quality of service and the channel conditions of users We thus propose to utilize the UAV as a computing node as well as a relay node to improve the average user latency in the UAV-aided MEC (UAV-MEC) network and formulate the UAV-MEC problem with the objective to minimize the average latency of all UEs As the UAV-MEC problem is NP-hard, we decompose it into three subproblems We propose an approximation algorithm with low complexity to solve the first subproblem and then we obtain the optimal solutions of the remaining two subproblems, upon which another proposed approximation algorithm employs these solutions to finally solve the UAV-MEC problem The evaluation results demonstrate that the proposed algorithm is superior to three baseline algorithms

Latency-Aware IoT Service Provisioning in UAV-Aided Mobile-Edge Computing Networks

Drone base stations (DBSs) can potentially provision low-cost and flexible networking with high mobility while in-band full-duplex (IBFD) can conceivably improve spectrum efficiency. Therefore, it is logical to employ DBSs with IBFD in a cellular network to improve the network throughput. We decompose this problem into the DBS placement problem and the joint bandwidth and power allocation problem, and propose two heuristic algorithms to solve the whole problem. Simulation results have demonstrated that the total throughput of the dynamic DBS placement algorithm achieves up to 45% improvement as compared with that of the strategy without DBSs.

3-D Drone-Base-Station Placement With In-Band Full-Duplex Communications

Translucent networks utilize sparse placements of optical-electronic-optical (O/E/O) 3R (reamplification, reshaping, and retiming) regenerators to improve the cost effectiveness and energy efficiency of wavelength-routed optical transport networks. In this paper, we show that the energy cost of a translucent network can be further reduced by leveraging the energy efficiency of all-optical 2R (reamplification and reshaping) regenerators. We propose a translucent network infrastructure that uses all-optical 2R regenerators to partially replace O/E/O 3R regenerators and implements mixed regenerator placements (MRP). We first consider the problem of MRP along a single given path, and propose three path-based impairment-aware MRP algorithms, based on periodic placement, genetic algorithm (GA), and ant colony optimization (ACO). We then address the offline network planning problem and develop a heuristic algorithm. By incorporating with one of the proposed MRP algorithms, the heuristic can achieve joint optimization of MRP and routing and wavelength assignment for high energy efficiency. We design simulations to compare the performance of different offline network planning scenarios and to see which one can provide the best balance between quality of transmission and energy cost. Simulation results show that the algorithm achieves 58.91-73.62% saving on regeneration energy, compared to the traditional scheme without all-optical 2R regenerators. The results also indicate that the joint optimization using the MRP-GA obtains the best network planning in terms of energy efficiency. Finally, we address the problem of online provisioning, and propose several algorithms to serve dynamic lightpath requests in translucent networks with MRP, and implement them in simulations to compare their performance in terms of blocking probability. Simulation results indicate that the online provisioning algorithm that utilizes the combination of the MRP-GA and a multiple MRP scheme achieves the lowest blocking probability.

Liang Zhang

Papers

Dynamic Service Provisioning in Elastic Optical Networks With Hybrid Single-/Multi-Path Routing

Highly efficient data migration and backup for big data applications in elastic optical inter-data-center networks

Latency-Aware IoT Service Provisioning in UAV-Aided Mobile-Edge Computing Networks

3-D Drone-Base-Station Placement With In-Band Full-Duplex Communications

Energy-Efficient Translucent Optical Transport Networks With Mixed Regenerator Placement