Mei Song

Improved ant colony-based multi-constrained QoS energy-saving routing and throughput optimization in wireless Ad-hoc networks

Abstract In order to establish a route supporting multi-constrained quality of service (QoS), increase network throughput and reduce network energy consumption, an improved ant colony-based multi-constrained QoS energy-saving routing algorithm (IAMQER) is proposed. The ant colony algorithm, as one of the available heuristic algorithms, is used to find the optimal route from source node to destination node. The proposed IAMQER algorithm, which is based on the analysis of local node information such as node queue length, node forwarding number of data packets and node residual energy, balances the relationship between the network throughput and the energy consumption, thus improving the performance of network in multi-constrained QoS routing. Simulation results show that this IAMQER algorithm can find the QoS route that reduce average energy consumption and improves network packet delivery ratio under the end-to-end delay and packet loss ratio constraints.

Energy efficient cooperative relaying and cognitive radio technologies to deliver green communication

So far, achieving high data rate has been the primary focus of research in wireless communication systems, without much consideration of energy efficiency. However, many of communication technologies significantly increase system complexity and energy consumption. In addition to the environmental problems that the governments restrict the greenhouse gases and pollution, energy costs also contribute a significant part of network operators overall expenditures due to the rapidly growing demand for mobile communication. Therefore, energy saving approaches are urgently required by both governments and network venders. Escalating energy costs and environmental concerns have already created an urgent need for more energy-efficient wireless communication. To address the challenge of increasing power efficiency in wireless networks and thereby to maintain profitability, this paper will discuss some research issues and challenges and suggest some paradigm-shifting technologies to enable an energy efficient or green cellular network.

End-to-end QoS guaranteed seamless handover scheme for cognitive heterogeneous networks

Roaming across heterogeneous wireless networks such as wireless wide area network (WWAN) and wireless local area network (WLAN) poses considerable challenges, as it is usually difficult to maintain the existing connections and guarantee the necessary end-to-end quality-of-service (QoS). This paper proposes a novel end-to-end QoS guaranteed seamless handover scheme, which can maintain the connections based on the end-to-end principle by incorporating an intelligent network status and environment detection mechanism. The proposed scheme consists of a new logical component, vertical handover manager (VHM). The VHM, by using application-layer, media access control-layer and physical-layer sensing techniques, can obtain accurate network condition and environment information, while at the same time reducing the unnecessary handover and ping-pong effect. Experiments have been performed to demonstrate the advantage of the proposed scheme.

OFDM frame synchronization based on energy difference of the received preamble

Abstract The article presents a novel orthogonal frequency division multiplexing (OFDM) frame synchronization method. The method uses the preamble that contains two identical halves, and the energy difference of the two similar parts of the received preamble in receiver is used to obtain the frames correct starting point Furthermore, an improvement of the proposed method is presented, which uses the preamble that can be divided into four similar portions, and the energy difference of the four similar parts of the received preamble in receiver is used to obtain the frames correct starting point. The performances of the frame synchronization methods in multipath channel are compared in terms of mean square error (MSE) obtained by simulations. It can be seen from the simulation results that the proposed methods have better performances than Schmidls, Minns, and Parks method in multipath channel.

Energy Saving Dynamic Relaying Scheme in Wireless Cooperative Networks Using Markov Decision Process

Energy saving becomes one of the most important design considerations in wireless cooperative networks which are composed of nodes typically powered by batteries that can supply only a finite amount of energy. In this paper, we propose a dynamic relaying scheme based on relay selection and physical-layer power control with the objective of minimizing the energy consumption for data transmission. We first develop a mathematical model for the cooperative relaying and analyze the total battery energy consumption to forward a symbol. Based on the analytic results and Markov channel model, we formulate the optimization problem that minimizes total average energy consumption as a Markov decision process, with which we can decide an optimal relay and the transmission power distributely. In the proposed scheme, the relay selection process and cooperation mode starts only when the direct transmission between source and destination node failed, which is energy efficient from a network sense. Numerical simulation show that the proposed scheme achieves significant energy savings.

A Distributed and Adaptive Location Management Scheme for Hierarchical Mobility Management

Hierarchical mobility management is sensitive to the failure of gateway mobility agents and prone to degrade performance on heavy loads. This paper proposes a distributed and adaptive location management scheme based on Hierarchical Mobile IPv6. This scheme can balance the loads of mobility anchor points and increase the robustness of the hierarchical structure to certain extents. In this scheme, the optimized IP paging scheme is adopted to reduce the paging signaling cost and improve the scalability of the hierarchical mobility management. We implement the distributed and adaptive location management scheme in a simulation platform and compare its performance with that of two other location management schemes. Our simulation results show that our scheme is capable of balancing the signaling and traffic loads of mobility ancher points, decreasing the average handover latency, and increasing the throughout of the visited networks.

Research of methodology of building modern service industry BI system based on NGOSS

Abstract As domestic modern service industry rises, research of supporting system for modern service industry is getting increasingly important. With reference to fundamental theory of building supporting system for telecommunication operation in telecommunication service industry (NGOSS), this paper proposes a set of fundamental methodologies and trains of thought for building supporting system for modern service industry. These methodologies are explained mainly in terms of dividing of development stages, main tasks of each stage, main effects to achieve etc. The paper also performs some verification on the aspect of business intelligence of modern service industry common services platform.

Green Precision Time Protocol Router Using Dynamic Frequency Scaling

Time is the only reference frame among all the network devices over the Internet. Clock synchronization is crucial, especially in time sensitive networking scenarios that every time stamp matters. The Precise Time Protocol PTP standard enables precise clock synchronization in multicast capable networks. With hardware time stamping, the standard provides exceptionally tight clock synchronization with the accuracy within the nanosecond range. For this reason, the PTP enabled routers have been widespread in recent years. However, the performance is traditionally the primary concern in these routers without drawing enough attention on router power consumption. This work builds an energy efficient PTP router using dynamic frequency scaling towards green networking. Results indicate that, when in idle state, the proposed router can significantly reduce up to 16.89i?ź% of the power consumption.

Energy efficiency in wireless cellular networks based on dynamic power allocation

Abstract Energy efficiency is increasingly vital for wireless cellular systems due to the limited battery resources of mobile clients. Among previous work, many studies suggest different methods to reduce the transmission power in case of a fixed condition. However, according to the mobility of users and continuous variation of cellular network environment, the traffic load of base station (BS) and the channel state information (CSI) are varying. In this paper, we proposed a dynamic power allocation schedule to assign transmit power to mobile users in the downlink, resulting in optimal energy saving. The novel power allocation scheme was based on the coordination of neighbouring cells. The results showed that the scheme dramatically reduce the average bit error rate (BER) and total tranmitted power of the system, with the improvement of network capacity.

A distributed location management strategy for next- generation IP-based wireless networks

Abstract Location management is the most important function in mobility management technology. The hierarchical structure of the proposed hierarchical network-layer mobility management (HNMM) can reduce the signaling cost. The selforganizing topology scheme can enhance the robustness and quality of the mobility management. The information of location of the mobile node is stored in the distributed database, which makes the storage of the location information more reliable and robust, and more flexible strategies can be used. The numeric results show that HNMM can provide better performance than the general structure of mobile IPv6, when the mobile nodes move frequently and when there is high traffic throughput.