Latency sensitive services have attracted much attention lately and imposed stringent requirements on the access network design. Passive optical networks (PONs) provide a potential long-term solution for the underlying transport network supporting these services. This paper discusses latency limitations in PON and recent progress in PON standardization to improve latency. Experimental results of a low latency PON system are presented as a proof of concept.

A review of signal processing algorithms employing Wi-Fi signals for positioning and recognition of human activities is presented. The principles of how channel state information (CSI) is used and how the Wi-Fi sensing systems operate are reviewed. It provides a brief introduction to the algorithms that perform signal processing, feature extraction and recognitions, including location, activity recognition, physiological signal detection and personal identification. Challenges and future trends of Wi-Fi sensing are also discussed in the end.

Benefited from the design of separating control plane and data plane, software defined networking (SDN) is widely concerned and applied. Its quick response capability to network events with changes in network policies enables more dynamic management of data center networks. Although the SDN controller architecture is increasingly optimized for swift policy updates, the data plane, especially the prevailing ternary content-addressable memory (TCAM) based flow tables on physical SDN switches, remains unoptimized for fast rule updates, and is gradually becoming the primary bottleneck along the policy update pipeline. In this paper, we present RuleTris, the first SDN update optimization framework that minimizes rule update latency for TCAM-based switches. RuleTris employs the dependency graph (DAG) as the key abstraction to minimize the update latency. RuleTris efficiently obtains the DAGs with novel dependency preserving algorithms that incrementally build rule dependency along with the compilation process. Then, in the guidance of the DAG, RuleTris calculates the TCAM update schedules that minimize TCAM entry moves, which are the main cause of TCAM update inefficiency. In evaluation, RuleTris achieves a median of <12 ms and 90-percentile of < 15ms the end-to-end perrule update latency on our hardware prototype, outperforming the state-of-the-art composition compiler CoVisor by ~ 20 times.

Currently, Infrastructure as a Service(IaaS) and Platform as a Service(PaaS) platforms play a role as a cloud operating system(COS).They are separated from each other in resource management, which may cause inconsistent resource status and result in the decrease of performance. Moreover, heterogeneous resources are not managed well in existing cloud computing platforms. Referring to the theory of operating system, we propose a unified architecture model of cloud operating system, which has six layers corresponding to the layered architecture of legacy operating system. Based on this architecture, a new cloud operating system called Hua-Cloud Computing System(HCOS) is realized. In HCOS, the hybrid resources are managed in a unified way. This method improves the unified scheduling capability of heterogeneous resources and eliminates the problem of resource status inconsistency. The main characteristics of HCOS are introduced and two typical applications are illustrated in this paper.

In the new era of railways, infrastructure, trains and travelers will be interconnected. In order to realize a seamless high-data rate wireless connectivity, up to dozens of GHz bandwidth is required. This motivates the exploration of the underutilized millimeter wave (mmWave) as well as the largely unexplored THz band. In this paper, we first identify relevant communication scenarios for railway applications. Then the specific challenges and estimates of the bandwidth requirements for high-data rate railway connectivity in these communication scenarios are described. Finally, we outline the major challenges on propagation channel modeling and provide a technical route for further studies.

Aiming at the low accuracy problem of power system short-term load forecasting by traditional methods, a back-propagation artificial neural network (BP-ANN) based method for short-term load forecasting is presented in this paper. The forecast points are related to prophase adjacent data as well as the periodical long-term historical load data. Then the short-term load forecasting model of Shanxi Power Grid (China) based on BP-ANN method and correlation analysis is established. The simulation model matches well with practical power system load, indicating the BP-ANN method is simple and with higher precision and practicality.

In traffic-monitoring systems, numerous vision-based approaches have been used to detect vehicle parameters. However, few of these approaches have been used in waterway transport because of the complexity created by factors such as rippling water and lack of calibration object. In this paper, we present an approach to detecting the parameters of a moving ship in an inland river. This approach involves interactive calibration without a calibration reference. We detect a moving ship using an optimized visual foreground detection algorithm that eliminates false detection in dynamic water scenarios, and we detect ship length, width, speed, and flow. We trialed our parameter-detection technique in the Beijing-Hangzhou Grand Canal and found that detection accuracy was greater than 90% for all parameters.

In a data center network (DCN), load balancing is required when servers transfer data on the same path. This is necessary to avoid congestion. Load balancing is challenged by the dynamic transferral of demands and complex routing control. Because of the distributed nature of a traditional network, previous research on load balancing has mostly focused on improving the performance of the local network; thus, the load has not been optimally balanced across the entire network. In this paper, we propose a novel dynamic load-balancing algorithm for fat-tree. This algorithm avoids congestions to the great possible extent by searching for non-conflicting paths in a centralized way. We implement the algorithm in the popular software-defined networking architecture and evaluate the algorithm’s performance on the Mininet platform. The results show that our algorithm has higher bisection bandwidth than the traditional equal-cost multi-path load-balancing algorithm and thus more effectively avoids congestion.

The emergency relating to software-defined networking (SDN), especially in terms of the prototype associated with OpenFlow, provides new possibilities for innovating on network design. Researchers have started to extend SDN to cellular networks. Such new programmable architecture is beneficial to the evolution of mobile networks and allows operators to provide better services. The typical cellular network comprises radio access network (RAN) and core network (CN); hence, the technique roadmap diverges in two ways. In this paper, we investigate SoftRAN, the latest SDN solution for RAN, and SoftCell and MobileFlow, the latest solutions for CN. We also define a series of control functions for CROWD. Unlike in the other literature, we emphasize only softwaredefined cellular network solutions and specifications in order to provide possible research directions.

In this paper, we survey data security and privacy problems created by cloud storage applications and propose a cloud storage security architecture. We discuss state-of-the-art techniques for ensuring the privacy and security of data stored in the cloud. We discuss policies for access control and data integrity, availability, and privacy. We also discuss several key solutions proposed in current literature and point out future research directions.

In this paper, we describe a novel technique based on the flipped-exponential (FE) Nyquist pulse method for reducing peak-to-average power ratio (PAPR) in an optical direct-detection orthogonal frequency-division multiplexing (DD-OFDM) system. The technique involves proper selection of the FE Nyquist pulses for shaping the different subcarriers of the OFDM. We apply this technique to a DD-OFDM transmission system to significantly reduce PAPR. We also investigate the sensitivity of a received OFDM signal with strong nonlinearity in a standard single-mode fiber (SMF).

Spatial mode-division multiplexing is emerging as a potential solution to further increasing optical fiber capacity and spectral efficiency. We report a dual-mode, dual-polarization transmission method based on mode-selective excitation and detection over a two-mode fiber. In particular, we present 107 Gbit/s coherent optical OFDM (CO-OFDM) transmission over a 4.5 km two-mode fiber using LP01 and LP11 modes in which mode separation is performed optically.

This paper presents a brief overview of several promising design technologies for high efficiency silicon-based radio frequency (RF) power amplifiers (PAs) as well as the use of these technologies in mobile broadband wireless communications. Four important aspects of PA design are addressed in this paper. First, we look at class-E PA design equations and provide an example of a class-E PA that achieves efficiency of 65-70% at 2.4 GHz. Then, we discuss state-of-the-art envelope tracking (ET) design for monolithic wideband RF mobile transmitter applications. A brief overview of Doherty PA design for the next-generation wireless handset applications is then given. Towards the end of the paper, we discuss an inherently broadband and highly efficient class-J PA design targeting future multi-band multi-standard wireless communication protocols.

Vehicular networks have traditionally been used in specific scenarios, such as Electronic Toll Collection (ETC). New vehicular networks, however, support communication of safety information between vehicles using self-organized ad-hoc technology. Because of limitations in network architecture, current vehicular networks only provide communication for mobile terminals in a vehicle cluster. Vehicles cannot exchange information with an Intelligent Traffic System (ITS) control center nor can they access broadband wireless networks. This paper proposes a novel heterogeneous vehicular wireless architecture based on Wireless Access in Vehicular Environment (WAVE, IEEE 802.11p) and Worldwide Interoperability for Microwave Access (WiMAX, IEEE 802.16e). A new network infrastructure and system model is introduced, and key technologies are discussed. For WAVE, these technologies include adaptive multichannel coordination mechanism and scheduling algorithm; and for WiMAX, these technologies include group handover scheme and two-level resource allocation algorithm.

As the information network plays a more and more important role globally, the traditional network theories and technologies , especially those related to network security, can no longer meet the network development requirements . Offering the system with secure and trusted services has become a new focus in network res earch . This paper first discusses the meaning of and aspects involved in the trusted network. According to this paper, the trusted network should be a network where the network s and users behaviors and their results are always predicted and manageable . The trustworthiness of a network mainly involves three aspects : service provider, information transmission and terminal user. This paper also analyzes the trusted network in terms of trusted model for network/user behaviors , architecture of trusted network, s ervice survivability and network manageability, which is designed to give ideas on solving the problems that may be faced in developing the trusted network.