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Mobile edge computing is popular for providing services with low latency and high privacy. It becomes more powerful by leveraging the widely deployed Small cell Base Stations (SBS) with zooming cells for energy-efficient service placement. However, the literature ignores the joint optimization of SBS power control and service placement. The Quality of Services (QoS) guarantee is also challenging, taking into account the component dependency and parallelization in multi-component services and the resource slicing for separated service deployment. Moreover, prior works assume the same amount of allocated resources of links on a placed path for service edge allocation, leading to the ossification of resource allocation and inevitable resource fragments. Towards the above challenges, this paper addresses the energy-efficient and flexible service placement in cell zooming enabled Mobile Edge Cloud (MEC) networks. The delay of multi-component services is constructed depending on the allocated resource slice. Besides, the joint optimization of service placement and SBS power control is formulated and transformed into a Mixed Integer Linear Programming (MILP). More importantly, the equivalent bandwidth for an edge allocation is defined and analyzed to obtain flexible edge placement with minimum resource cost. Leveraging the results of MILP, an Energy-efficient Service placement algorithm based on equivalent Bandwidth in Cell zooming enabled MEC networks (ESBC) is proposed to improve the probability of successful service placement with QoS guarantee by optimizing the delay distribution among components and edges and reducing resource fragments. Finally, simulation results validate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

Background. Cervical cancer, the only gynecological malignancy for which a clear pathogeny has been established, has an incidence rate only second to breast cancer. Objective. In our study, we aim to investigate the clinical effect of laparoscopic radical surgery combined with neoadjuvant chemotherapy in treating cervical cancer and its influence on postoperative complications and adverse reaction rates. Methods. Cervical cancer patients admitted to our hospital from August 2018 to May 2020 were retrospectively analyzed as the research object and divided into the control group and the experimental group by the draw method, with 50 cases in each group. The laparoscopic radical surgery was performed on the control group, and the laparoscopic radical surgery combined with neoadjuvant chemotherapy was performed on the experimental group to compare their effective rates, adverse reaction rates, postoperative complication rates, expression levels of serum tumor necrosis factor-α (TNF-α) and soluble interleukin-2 receptor (SIL-2R) inside the body before surgery and at one week after surgery, quality of life (QLI) scores, and Mental Status Scale in Nonpsychiatric Settings (MSSNS) scores. Results. Compared with the control group, the experimental group obtained significantly higher effective rate and QLI scores (P < 0.05) and significantly lower adverse reaction rates, postoperative complication rates, expression levels of serum TNF-α and SIL-2R inside the body at one week after surgery, and MSSNS scores (P < 0.05), with statistical differences; before surgery, the TNF-α and SIL-2R expression levels of the two groups were not significantly different (P > 0.05), but the levels at one week after surgery were significantly lower than those before, indicating statistical significance (P < 0.05). Conclusion. The clinical effect of laparoscopic radical surgery combined with neoadjuvant chemotherapy can obviously improve the effective rate of cervical cancer patients and lower the incidence rates of postoperative complications and adverse reactions. [ABSTRACT FROM AUTHOR]

To overcome the Internet ossification, network virtualization has been proposed as a promising method because of its advantages (e.g., on-demand and efficient resource allocation). Virtual network embedding (VNE) is one of the main challenges for network virtualization. Energy costs of servers in data centers (DCs) aremajor contributions to the power consumption in information and communication technology. Therefore, VNE should consider both acceptance ratio and power consumption. In this paper, a mixed integer linear programming model is proposed with the objective of minimizing the total power consumption in software- defined optical data center networks by reducing the active data centers and power-consuming network components. In addition, the coordinates of nodes and delay of links are considered for a more realistic scenario. Compared with the existing node ranking method, the proposed global topology resource (GTR) can effectively evaluate the possibility of each DC node to host virtual nodes. Based on the GTR method, we propose a location-aware energy efficient VNE algorithm, namely GTR-VNE. Simulation results show that GTR-VNE can obtain up to 9.3% and 5% improvement of power consumption and acceptance ratio compared with benchmarks. Furthermore, based on GTR and artificial intelligence ant colony optimization (ACO), another energy efficient algorithm, ACO-VNE, is proposed.ACO-VNE can obtain up to 28.7% improvement in power consumption compared with GTR-VNE. In addition, ACO-VNE has better performance in terms of revenue cost ratio and acceptance ratio. [ABSTRACT FROM AUTHOR]

Optical data center networks (ODCNs) are constructed by connecting geographically distributed data centers with optical networks. Due to the superiorities in computing and transmission performances, ODCNs have been widely acknowledged as a promising network paradigm to support the popular enterprise IT applications such as cloud computing and 3D rendering. However, the ever-increasing traffic burst and the expensive hardware upgrading impose more severe challenges on the design of resource allocation scheme in ODCNs, which is urgently required to take into account not only the service quality but also the economical profit of service provider. In this paper, we focus on the service degradation in ODCNs which has been proven efficient in reducing the denied requests in the overloaded network scenario by releasing portion of the occupied network resources with the acceptable service quality loss. Unlike the service degradation scheme in previous works, we first consider the impact of the time characteristics of service requests on the resource utilization and propose a novel time-dependent load-balancing service degradation (TD-LBSD) framework. In the TD-LBSD framework, a time-dependent link weight scheme is invented for the allocation of bandwidth resource to avoid the potential traffic congestion that is usually induced by the ignored dynamic nature of service requests. In order to support the high-level prepaid requests with unknown holding time, we also propose a statistical method to estimate the residual time of the occupied lightpaths based on the probability distribution of the holding time of past requests. Simulation results verified that our proposed service degradation framework outperforms the previous schemes with the profit gain of 6.2% and the reduced traffic congestions of 16.39% at best. [ABSTRACT FROM AUTHOR]

Abstract?Hybrid fiber-wireless (FiWi) networks, which benefit from high bandwidth and ubiquitous access of optical and wireless networks, have been identified as a promising technology candidate for next-generation broadband access. As various component/fiber failures may occur in hybrid FiWi networks, thus affecting huge numbers of end users, survivability has become one of the key important deployment considerations in such networks. This paper focuses on developing optimal network planning strategies to achieve survivable hybrid FiWi networks. In particular, to address the additional cost involved in deploying backup fibers in previously proposed redundancy strategies against distribution fiber failures, we propose the use of wireless routing through the ubiquitous wireless coverage of end users in a hybrid FiWi network. We present an optimization framework to optimally plan and deploy a survivable hybrid FiWi network, where traffic from an affected optical network unit (ONU) can be effectively rerouted to backup ONUs through wireless connections in the event of a distribution fiber failure. However, focusing only on the resilience of a network without considering its cost, and ignoring the resultant capacity, latency, and coverage under normal and protection operating conditions, is impractical. Our proposed framework therefore ensures maximum end-user coverage whilst satisfying survivability, connectivity, delay, and capacity constraints of the network, by optimizing the placement of passive optical splitters, ONUs, and wireless routers in conjunction with fiber and wireless connections. Moreover, we demonstrate the feasibility of our framework in the context of an urban deployment under different deployment scenarios. In particular, our results provide insight into how survivable FiWi networks can be deployed without compromising on the latency, coverage, and capacity requirements of such networks. [ABSTRACT FROM PUBLISHER]

The fiber-wireless (FIWi) access network not only leverages the technical merits of wireless and optical access networks, but also provides a potential opportunity for the design of survivable access networks. Previous works have studied the survivability of FiWi access network against network component failure by means of backup fiber deployment and wireless rerouting. However, most of these works put less attention on the connection availability and ignore the joint allocation of wireless and optical resources, which plays an important role in improving the global network performance gain. In this paper, we consider a notable failure scenario in FiWi access network but less mentioned in previous works, i.e., single shared-risk link group failure. We first propose a model for FiWi network to estimate the connection availability of service demand. Then, a novel resource allocation approach is proposed to provide the availability-guaranteed service. Under the requirements of bandwidth and connection availability, we deal with the optimal allocation of joint wireless and optical resources with the objective of minimum resource consumption. Numerical results demonstrate that the proposed scheme can reduce the resource consumption significantly compared to the resource allocation without considering connection availability. [ABSTRACT FROM AUTHOR]

Passive optical network (PON) has become a preferable access technique for cloud computing due to its elastic bandwidth capacity and transmission stability. In particular, the orthogonal frequency division multiplexing PON based on intensity modulation and direct detection (IM/DD OFDM-PON) has gained extensive attention since it is a cost- and spectral-efficient system, while for the traditional IM/DD OFDM-PON, the use of OFDM could lead to the high peak-to-average power ratio (PAPR), and it is impossible to satisfy the different QoS degrees required by ONUs under a cloud environment. Thus in this paper, we design a novel multi-band discrete Fourier transform (DFT)-spread IM/DD OFDM-PON. The DFT-spread is utilized to reduce the PAPR; meanwhile, a multi-band power allocation and bit loading are achieved to satisfy the different degrees of QoS requirement owned by ONUs. The simulation results show that our system has the better performance of PAPR reduction compared with the traditional IM/DD OFDM-PON; meanwhile, the different QoS degrees of all ONUs are guaranteed. [ABSTRACT FROM AUTHOR]

Cloud-integrated fiber-wireless (FiWi) networks inheriting advantages of optical and wireless access networks have a broad prospect in the future. As various component failures may occur in cloud-integrated FiWi networks, survivability is becoming one of the key important issues. It is necessary to provide survivability strategies for cloud-integrated FiWi networks. Hence, this paper mainly focuses on the survivability of cloud-integrated FiWi networks against multiple fibers failure. Firstly, in this paper, a novel integer linear programming (ILP) solution is proposed to tolerate the failure of multiple distribution fibers with capacity and coverage constraints in the context of urban area. Then, considering the complexity of ILP models, an efficient heuristic scheme is proposed, in order to get the approximate solutions of ILP. Simulation results and analysis give the configurations of optical network units (ONUs) and wireless routers with different constraints and show the network coverage of clients for different number of ONUs and wireless routers with ILP solution and heuristic approach, respectively. [ABSTRACT FROM AUTHOR]

Due to the massive deployment of electrical network devices, Fiber-Wireless (FiWi) access network has to suffer from the challenge of high energy consumption. With the ever-increasing eager for green communication infrastructure, the issue of high energy consumption may become one of the major barriers for the advance of FiWi access network. Previous works proposed for green FiWi access network cover three aspects, including the optimized deployment of network devices such as optical network units (ONUs), the energy-efficient bandwidth allocation of ONUs with QoS guarantee, and the dynamic power states scheduling of ONUs (i.e., active/sleep) according to their traffic profile. However, these works did not take the energy-saving design of wireless subnetwork into account simultaneously. In fact, when some ONUs in the optical subnetwork are switched into sleep states, part of the radio interfaces originally forwarding traffic to the sleep ONUs would be idle or low-loaded. This provides a potential opportunity for energy-saving in wireless subnetwork by switching off the idle or low-loaded radios. This paper focuses on the design of green multi-radio FiWi access network by integrating the energy-savings of optical and wireless subnetworks. To support the energy-efficient design, the new power states are defined for ONUs and radios, respectively. Aiming at dynamic traffic profile, the heuristic algorithms are proposed for the energy saving of integrated wireless front-end and optical back-end of FiWi access network. First, the Energy-saving algorithm with ONU sleep mechanism (EAS) is proposed to dynamically schedule the power states of ONUs by judging their traffic profile with load thresholds. Then, the Energy-saving algorithm based on Radios Off (ERO) is proposed to reconfigure the topology of wireless subnetwork by controlling the power states of radios dynamically. Moreover, wireless rerouting is employed in both EAS and ERO to guarantee the QoS provisioning ability of network. Finally, a comprehensive energy-saving scheme called EE is proposed by combining the EAS and ERO algorithms strategically. Simulation results show that with the reasonable setting of parameters, the proposed EE scheme can save the energy of 33.14% to 64.35% and 8.56% to 36.42% in a wide range of traffic load compared to the No-energy-saving and QoS-aware energy-saving scenarios, respectively. [ABSTRACT FROM PUBLISHER]

The intensity modulation and direct detection (IM/DD) passive optical network (PON) has been demonstrated as a cost-effective solution for a long-reach ( $$>\!80\,\hbox {km}$$ ) access system because it can be easily installed and maintained with low cost and complexity. Meanwhile, orthogonal frequency division multiplexing (OFDM) has been widely used in PONs due to its high spectral efficiency and strong resistance to dispersion impairments. So, the IM/DD OFDM-PON emerged. The power efficiency has attracted great research interests in IM/DD OFDM-PONs. The previous works achieved power savings from the perspective of MAC-layer or hardware-level optimization, but they neglected designing appropriative algorithms, and the long-reach transmission performance cannot be guaranteed. In this paper, we propose an improved Hughes-Hartogs algorithm (IHHA) to adjust the number of bits and power level allocated for each subcarrier, with the objective to minimize the electrical transmitting power of all subcarriers. The OFDM signal is generated according to the bit/power allocation result of IHHA, and we conduct extensive simulations to verify the long-reach transmission performance of our system. Simulation results show that our system has high power efficiency by using IHHA, and bit error rate satisfies the forward error correction limitation after 100 km single-mode fiber transmission. [ABSTRACT FROM AUTHOR]

High energy consumption in Ethernet Passive Optical Networks (EPONs) has caused intense research on energy-saving methods in recent years. The most common method for EPON energy saving is to cause optical network units (ONUs) to sleep which are idle or low loaded. With the popularity of multimedia applications, the ONUs carry not only unicast traffic but also more and more multicast traffic. However, existing studies mainly focus on ONUs that support only unicast traffic. The many differences between multicast traffic and unicast traffic make it necessary to design novel energy-saving methods. This paper proposes a multicast-traffic-oriented energy-saving algorithm for EPONs, called the energy-saving algorithm for multicast traffic (ESMT). To save as much energy as possible, the proposed algorithm uses a hybrid sleep mode (composed of a deep sleep state and an independent sleep mode) in which not only can ONU enter a deep sleep state, but also the ONU transmitter and receiver can sleep independently. Simulation results show that the proposed algorithm, which is oriented to multicast traffic in EPONs, is more energy efficient than other algorithms. [ABSTRACT FROM AUTHOR]

Energy savings in Internet have been regarded as a significant technical issue for academic and industrial community. Particularly, access network accounts for more than 70% of the total energy consumption of Internet. As a promising access technique, Fiber-Wireless (FiWi) network not only enables the cost-effective broadband access, but also provides more opportunities for energy savings. Previous works mostly focused on the energy savings in the optical back-end of FiWi. Generally, they extended the Optical Network Unit (ONU) sleep mechanisms initially designed for Passive Optical Network (PON) to FiWi by combining with the wireless rerouting. However, most of these works left the energy savings in the wireless front-end untouched. In fact, when one or more ONUs in the network is/are sleeping, many wireless components remain idle or underutilized which cause a lot of energy waste. Motivated by this, we propose a new integrated Wireless-Optical Energy Savings (WOES) scheme for the comprehensive energy savings in FiWi. The WOES scheme consists of two interactive modules, Energy-Efficient ONU Management (EEOM) and Energy-Aware Topology Configuration (EATC). EEOM aims at the energy savings in the optical back-end by putting the low-load ONUs into sleep state. A pair of thresholds is introduced into EEOM to maintain the states of ONUs. As soon as ONUs states change, EATC will reconfigure the wireless topology by putting the idle Radio Interfaces (RIs) into standby state, thus minimizing the energy consumption of the wireless front-end. Simulation results show that the WOES scheme can reduce the energy consumption significantly with just a little performance degradation in network throughput and end-to-end delay. [ABSTRACT FROM AUTHOR]

The hybrid Wireless-Optical Broadband Access Network (WOBAN) provides a new and promising architecture for broadband access network by combining the beneficial properties of wireless and optical access technologies. To avoid huge data loss, WOBAN needs to be designed with a high availability guarantee. The purpose of this paper is to protect the Passive Optical Network at the back-end using the backup radios in Wireless Mesh Network at the front-end. The proposed protection scheme is based on a connection availability model. First, we assigned several backup Optical Network Units (ONUs) for each primary ONU not satisfying the availability requirement of primary optical connection. Under the availability requirement of backup optical connection, each backup ONU needed to reserve the residual capacity as the backup capacity to fully protect the traffic demand of its primary ONU. Then, we selectively deployed the additional radio interfaces as the backup radios for the wireless routers in the front-end under the availability requirement of backup wireless connection, in order to establish the wireless-backup-path between each pair of primary and backup ONUs. Each backup radio on the wireless-backup-path will retain the backup radio capacity for rerouting traffic, so as to decrease the possibility of traffic block in case of failure. We aimed to design efficient heuristic algorithms and yield suboptimal solutions for minimizing the consumption of backup ONU capacity and the cost of backup radios. Simulation results demonstrate the advantage of the proposed scheme compared to previous works. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) were measured in sewage sludge samples collected from major wastewater treatment plants in Guangdong Province, South China. Concentrations of ∑ 39PBDE (all 39 compounds including tri- to hepta- PBDE congeners except for BDE-209) ranged from 3.6 to 428 ng/g dw with a mean value of 67.4 ng/g dw and a median value of 25.9 ng/g dw, and those of BDE-209 ranged from 9.9 to 5,010 ng/g dw (mean 1,024 ng/g dw and median 824 ng/g dw). The PBDE mixtures detected were mainly comprised of penta-, octa-, and deca-BDEs, with deca-BDE as the dominant constituent. The most abundant congeners, excluding BDE-209, were BDE-47, BDE-99, and BDE-183. Good correlations were found among the concentrations of BDE-47, BDE-99, BDE-100, BDE-138, and BDE-154 ( r > 0.8). However, poor correlations were found between the concentrations of BDE-209 and all other congeners ( r < 0.3). This fact suggests that most tri- to hepta-BDEs detected did not originate from decomposition of deca-BDE. The estimated annual emission of ∑ allPBDEs, ∑ 39PBDEs, penta-BDE, octa-BDE, and deca-BDE to the Pearl River Delta environment (PRD), based on the sludge samples analyzed, amounts to 232, 20.2, 5.5, 1.7, and 212 kg per year, implicating sewage sludge as a significant source of PBDEs to the PRD environment. [ABSTRACT FROM AUTHOR]

With the development of WDM techniques and cloud computing, incorporating the optical backbone into data centers has received extensive attention. Virtual network (VN) planning has been proposed for this new networking paradigm by taking advantage of network virtualization. VN planning is essentially a united virtualization of optical and server resources in a collaborative manner. In this article, we first elaborate the advantages and problems of existing VN planning schemes through a comprehensive survey. Next, we provide a VN planning scheme. The simulation results demonstrate the effectiveness of our strategy, particularly in the context of power outage and evolving recovery. Finally, the future opportunities and challenges are also discussed. [ABSTRACT FROM PUBLISHER]

Survivability is one of the key issues in fiber-wireless (FiWi) access networks, since network component failure may cause huge data loss. Especially in the scenario of segment failure, all optical network units (ONUs) lose their connections with the optical line terminal. Previous works focus on the protection of FiWi against segment failure by deploying backup fibers among the backup ONUs in different segments. However, these works consider only single segment failure. They also ignore the issue of traffic recovery efficiency. More importantly, they underutilize the backup fibers and ignore optimizing the selection of backup ONUs. Therefore, these works usually require a considerable deployment cost for backup fibers. To conquer these challenges, we propose an efficient protection scheme called cluster-based protection (CBP) in this paper. In CBP, we first partition the segments in the network into clusters in order to reduce the overhead for the management of traffic recovery. Then, we select one of the ONUs in each segment as the backup ONU and deploy backup fibers among the backup ONUs of different segments in the same cluster. Under a constraint on the maximum number of segments in each cluster, the CBP scheme aims to protect FiWi against the simultaneous failures of multiple segments with a minimum deployment cost for backup fibers. We propose both an integer-linear-programming-based approach and a heuristic approach to solve the joint optimization problem in CBP of selecting backup ONUs, clustering segments, and deploying backup fibers. To the best of our knowledge, this paper is the first work regarding the survivability of FiWi against the simultaneous failures of multiple segments. Through extensive simulation, we demonstrate that our CBP scheme outperforms the previous works significantly in terms of survivability enhancement and cost savings. [ABSTRACT FROM PUBLISHER]

Orthogonal Frequency Division Multiple Access (OFDMA) is an attracting system for combating the frequency selective fading. It's widely considered as a promising candidate modulation and access scheme for next generation mobile communication systems. However, the explosive growth of multimedia applications raises higher performance requirements for Radio Resource Management (RRM) in OFDMA system. In particular, limited bandwidth and fierce resource competition impose a challenging issue on the design of packet scheduler. In this paper, we propose two scheduling algorithms applicable to mixed services (i.e., real-time and non-real-time services), that is QoS-oriented Dynamic Threshold Control (DTC) algorithm and fairness-oriented Fairness Aware and QoS Aware (FAQA) algorithm. These two algorithms are both composed of two stages, i.e., initial subcarrier allocation and subcarrier reallocation. For the DTC algorithm, in the stage of initial subcarrier allocation, based on the different metrics to weigh QoS between both services, we design a unique scheduling strategy for each type of service. A dynamic threshold is adopted to help users quickly recover from starvation, so that any one user in system can escape from severely degraded QoS. In the stage of subcarrier reallocation, we will reallocate the surplus subcarriers from the buffer-empty users to the buffer-nonempty users so as to increase spectrum efficiency. For FAQA algorithm, in the stage of initial subcarrier allocation, for the purpose of achieving Proportional Fairness (PF) with lower complexity, we deduce a simple scheduling strategy satisfying PF criterion by means of Greedy algorithm. In the stage of subcarrier reallocation, in order to increase the number of users satisfying QoS requirements, we'll reallocate the surplus subcarriers from the QoS-satisfied users to the QoS-unsatisfied users. Simulation results demonstrate that, on one hand, the DTC algorithm not only guarantees the quality of both services, but also increases the spectrum efficiency; on the other hand, the FAQA algorithm well maintains the fairness among users, and increases the QoS satisfaction degree at the same time. [ABSTRACT FROM AUTHOR]

Due to the rapid growth of various applications, the network devices scale and complexity are significantly increased. Meanwhile, to deal with the burst IP traffic, the network devices need to provide continuous services, which will result in the excessive power consumption. Meanwhile, with the development of IP network and intelligent optical switch network, the backbone network tends to be an IP over wavelength-division-multiplexing (WDM) network. Therefore, it has attracted wide interests in both academic and industrial communities to build power-efficient (i.e., green) IP over WDM network, where we can switch several IP-level requests as one unit in the WDM optical layer. This method is called hybrid grooming and it requires less component power than that of electronic IP routers in the IP layer. Under this hybrid approach, the traffic grooming multiplexes many IP-level requests into a high-capacity lightpath; meanwhile the reduction in power consumed by optical-electrical-optical conversions is achieved through optical bypass. However, the power consumed by components used to establish lightpaths should also be considered. One network with the higher power efficiency not only saves more power followed by hybrid grooming but also requires the lower power consumption of establishing lightpaths. In this paper, to improve the power efficiency of dynamic IP over WDM network, we design two kinds of Wavelength Integrated Auxiliary Graphs (WIAGs), each of which contains one Virtual Topology Layer and multiple Wavelength-Plane Layers. Based on WIAGs, we propose two heuristic algorithms named single-hop grooming with considering power efficiency and multi-hop grooming with considering power efficiency (MGPE) since grooming is NP-hard. Simulation results demonstrate that MGPE obtains the higher power efficiency, although it has the slightly higher time complexity; the power efficiency mainly depends on the kind of grooming strategy (single- or multi-hop) we use while the increasing number of available transceivers in each node cannot improve the power efficiency, although it can make blocking probability decrease. [ABSTRACT FROM AUTHOR]

The emerging 5G applications and the connectivity of billions of devices have driven the investigation of multi-domain heterogeneous converged optical networks. To support emerging applications with their diverse quality of service requirements, network slicing has been proposed as a promising technology. Network virtualization is an enabler for network slicing, where the physical network can be partitioned into different configurable slices in the multi-domain heterogeneous converged optical networks. An efficient resource allocation mechanism for multiple virtual networks in network virtualization is one of the main challenges referred as virtual network embedding (VNE). This paper is a survey on the state-of-the-art works for the VNE problem towards multi-domain heterogeneous converged optical networks, providing the discussion on future research issues and challenges. In this paper, we describe VNE in multi-domain heterogeneous converged optical networks with enabling network orchestration technologies and analyze the literature about VNE algorithms with various network considerations for each network domain. The basic VNE problem with various motivations and performance metrics for general scenarios is discussed. A VNE algorithm taxonomy is presented and discussed by classifying the major VNE algorithms into three categories according to existing literature. We analyze and compare the attributes of algorithms such as node and link embedding methods, objectives, and network architecture, which can give a selection or baseline for future work of VNE. Finally, we explore some broader perspectives in future research issues and challenges on 5G scenario, field trail deployment, and machine learning-based algorithms. [ABSTRACT FROM AUTHOR]