Pengchao Han

A new virtual network embedding framework based on QoS satisfaction and network reconfiguration for fiber-wireless access network

Fiber-Wireless (FiWi) access network, which could provide an anytime-anywhere access for end users with high bandwidth capacity and long distance, is facing the challenge of resource allocation and optimization due to the complexity and diversity of traffic demands. Though network virtualization becomes a promising solution, which allows heterogeneous virtual networks coexisting on the shared substrate network, previous works ignored both varied requirements of Quality of Service (QoS) satisfaction of virtual networks and the flexibility of reconfiguring the resource of substrate FiWi access network. In this paper, we propose a new Virtual Network Embedding (VNE) framework based on QoS satisfaction and network reconfiguration. By equipping each virtual network with a specific QoS satisfaction requirement, the characteristics of virtual network demands are formulated from a more practical point of view. Moreover, the adaptive bandwidth allocation of substrate network and virtual network reconfiguration are exploited to maximize the InP revenue. Simulation results demonstrate that our proposed VNE algorithm outperforms previous approaches with multifold increment of InP revenue.

Joint Wireless and Optical Power States Scheduling for Green Multi-Radio Fiber-Wireless Access Network

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.

Virtual Network Embedding in SDN/NFV based Fiber-Wireless Access Network

Network Virtualization, which allows multiple Virtual Networks (VN) coexisting on a common Substrate Network (SN) with the guarantee of logical independence and security, provides a new solution for the global resource optimization of Fiber-Wireless (FiWi) access network. However, little attention has been paid to the implementation of the customized functions and protocols of VNs. Software-Defined Network (SDN), which changes how networks are managed by providing a logically centralized controller, is a revolution of network and becomes a promising way for the control and management of virtualized FiWi access network. Furthermore, Network Function Virtualization (NFV) has come into view for its ability of providing multiple network functions with low cost. Particularly, Virtual Network Embedding (VNE) is one of the most import issues in network virtualization. Prior works ignore the flexibility of resource reconfiguration of SN. In this paper, the architecture of SDN/NFV based FiWi access network virtualization is proposed. Under the proposed architecture, we further propose a VNE algorithm based on network reconfiguration. Two network reconfiguration operations are exploited and a channel reallocation scheme is proposed to restrict the channel reallocation cost of wireless radio interface. Simulation is implemented to demonstrate the effectiveness of proposed algorithm in increasing the VN acceptance ratio and the revenue of infrastructure provider.

Joint wireless and Optical Resources Allocation based on connection availability in FiWi access network

Protection against component failure is one of the key issues in the development of Fiber-Wireless (FiWi) access network. Most of the previous protection approaches for FiWi 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 performance gain. In this paper, a new model is proposed for FiWi access network to estimate the connection availability. Under the requirements of bandwidth and connection availability, we focus on the optimal allocation of joint wireless and optical resources aiming to minimize resource consumption.

Green virtual network embedding framework based on zooming small cells in Fiber-Wireless access network for 5G

The converged Fiber-Wireless (FiWi) access network that can provide service to users with a high capacity, flexibility and reliability has become a promising “last mile” solution for the Fifth Generation (5G). Network virtualization is capable of shielding the heterogeneous features of physical networks and facing the emergence of Over the top (OTT) content, which is consistent with the vision of 5G, where energy efficiency is one of the key issues. This paper concerns the green virtual network embedding scheme in virtualized FiWi access network for 5G, where the zooming small cell is designed. On one hand, the energy can be saved by decreasing the transmitting power of Small cell Base Stations (SBSs) reasonably. On the other hand, the virtual node embedding can be optimized through zooming the coverage of small cells and the zero-loaded SBSs can be switched into sleep state for energy-saving.

Directional routing algorithm for deep space optical network

With the development of science, economy and society, the needs for research and exploration of deep space have entered a rapid and stable development stage. Deep Space Optical Network (DSON) is expected to become an important foundation and inevitable development trend of future deep-space communication. In this paper, we design a deep space node model which is capable of combining the space division multiplexing with frequency division multiplexing. Furthermore, we propose the directional flooding routing algorithm (DFRA) for DSON based on our node model. This scheme selectively forwards the data packets in the routing, so that the energy consumption can be reduced effectively because only a portion of nodes will participate the flooding routing. Simulation results show that, compared with traditional flooding routing algorithm (TFRA), the DFRA can avoid the non-directional and blind transmission. Therefore, the energy consumption in message routing will be reduced and the lifespan of DSON can also be prolonged effectively. Although the complexity of routing implementation is slightly increased compared with TFRA, the energy of nodes can be saved and the transmission rate is obviously improved in DFRA. Thus the overall performance of DSON can be significantly improved.

Joint wireless and optical resources allocation for availability-guaranteed service in survivable fiber-wireless access network

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.

Joint relay selection and link scheduling in cooperative free-space optical system

Abstract. Free-space optical (FSO) communication system is vulnerable to link disruption due to the propagation loss and atmospheric turbulence. Cooperative FSO system has been proposed to mitigate the adverse effects of link disruption by the cooperative transmission in assistance of relay. However, most of the related works focus on the outage probability analysis and put less attention on the resource utilization. In fact, there exists a waste of bandwidth resource due to time slot waiting and more FSO transceivers are occupied. We mainly focus on the relay selection and link scheduling mechanisms of cooperative FSO system to improve not only network reliability but also resource utilization. We first propose a relay selection algorithm as a solution to combat channel fading. In the relay selection algorithm, two cooperative modes including intrarelay-set and inter-relay-set cooperative modes are proposed to enhance network capacity. Then, a link scheduling algorithm is further proposed to improve the bandwidth utilization and reduce the occupancy rate of transceivers by utilizing more sufficiently the idle FSO links. Simulation results show that the proposed algorithms can provide significant performance gain for cooperative FSO system in reliability and resource utilization and are highly suitable for the growing traffic demands.

QoS satisfaction aware and network reconfiguration enabled resource allocation for virtual network embedding in Fiber-Wireless access network

Abstract Network virtualization emerges as a revolutionary transformation for network operation pattern, which potentially benefits Fiber-Wireless (FiWi) access network by overcoming the bottleneck of joint wireless and optical resource allocation. On one hand, the heterogeneity between optical and wireless subnetworks that has posed severe challenges on the global optimization of FiWi can be tackled using network virtualization by shielding their physical differences. On the other hand, the flexible nature of resource scheduling in FiWi provides an opportunity for Infrastructure Provider (InP) to obtain high profit in the process of Virtual Network Embedding (VNE). In this paper, we highlight the VNE problem in FiWi access network. The wireless channel allocation algorithm and dynamic bandwidth allocation algorithm in FiWi are put forward, based on which the Integer Liner Programming (ILP) model of VNE problem in FiWi access network is formulated mathematically where a practical model of Virtual Network (VN) is focused by endowing each VN with a unique QoS satisfaction requirement. Moreover, aiming at maximizing InP profit, a QoS satisfaction aware VNE algorithm is designed and then improved by network reconfiguration mechanisms that enable the reconfiguration of not only virtual networks but also substrate network. Simulation results demonstrate that our proposed algorithms are effective in achieving higher VN acceptance ratio as well as InP profit. Furthermore, the mobility in network virtualization is analyzed in company with suggested solutions for virtualized FiWi access network. Comprehensive designs will be addressed in future work.

Survivable deployment of cloud-integrated fiber-wireless networks against multi-fiber failure

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.