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In the Cloud Computing, the migration mechanism can provide services, computing jobs and resources moved from a virtual environment to another virtual environment, and service providers can fit out their logic network architectures to offer services for user requirements. The network live migration across the different networks is a big challenge of the migration mechanism. In the paper, logical network architecture was proposed to provide the Cloud Computing in a hybrid network environment. The logical network concept, tunnel technology, domain name service and some existing network protocols were integrated into the proposed mechanism to provide network live migration across the different networks. The proposed mechanism implemented based on Open vSwitch and XEN. In our experimental results, we confirm that the proposed mechanism can provide network live migration across the different networks, and the network service will not be break. The performance evaluations also show that the proposed architecture can better than the NEMO solution.

The discovery and management of desired network services present significant challenges for mobile networks. Based on the Service Location Protocol, this paper proposes an integrated service discovery architecture for vehicular ad hoc networks. The proposed approach divides the network into several logical zones. The zone structure is formed virtually based on position information. Each logical zone may have a zone directory agent to manage registered services from service providers. The proposed architecture considers both vehicle-to-infrastructure and vehicle-to-vehicle communication modes and introduces roadside directory agents and vehicle directory agents to reduce deployment costs. We also introduce a substitute query technique, cache mechanism, and backup mechanism to improve the request hit ratio and reduce the message overhead of the substitute query. Finally, we implement the proposed mechanisms in Network Simulator version 2, with simulation results showing that the proposed architecture can provide a high average data hit ratio and low message overhead. Copyright © 2016 John Wiley & Sons, Ltd.

In the near future, home networks are expected to become an important part of the user's ubiquitous environment. However, how to provide service discovery and multimedia services in such networks becomes a great challenge. In the paper, we propose an extension header, referred to as the ''MediaService'' header, into the Session Initiation Protocol to provide video streaming service. The streaming control and session mobility functions are also considered in the MediaService header. We also propose a peer to peer Service Location Protocol architecture for users to search for location of services across domains. We added a Substitute Request Message and cache policy into the Service Location Protocol to search for location of services across domains. A prototype implementation shows the performance of our prototype.

Recently, most of Voice over Internet applications are based on the Session Initiation Protocol (SIP). This paper addresses issues of allowing a user to continue to communicate with a remote party while changing terminals over multiple devices. Specifically, we propose an SIP extension header to improve the Call Transfer mechanism and hide the changing of the terminal from the remote party. We also propose a mechanism to solve the problem of the user needing to terminate all devices separately when a session is split over multiple devices. Finally, the proposed mechanisms are implemented using Sip-Communicator, an open source of SIP.

3G must offer high data rates since it should support real-time multimedia services; one performance enhancement, the use of the OVSF code tree, has adopted in 3G WCDMA networks. Unfortunately, this technique allows the link capacity to be set at the base rate times powers of two. This results in wasting bandwidth while the required rate is not powers of two of the basic rate. Several multi-code assignment mechanisms have been proposed to reduce the waste rate, but incur some drawbacks, including high complexity of handling multiple codes and increasing cost of using more rake combiners. Our solution is a dynamic grouping code assignment that allows any rate to be achieved with a single code for any possible rate of traffic. The dynamic grouping approach first forms several calls into a group. It then allocates a subtree to the group and dynamically shares the subtree codes based on time-sharing of slots within a group cycle time. The waste rate and code blocking is thus reduced significantly. Since transmission delay and jitter may occur in such a time-sharing approach, two schemes of cycle interleaving are proposed to minimize delay and jitter. Numerical results demonstrate that the proposed approach reduces the waste rate and increases the system utilization obviously, and the proposed cycle interleaving schemes minimizes delay and jitter significantly.

This paper presents an integrated solution for code management, assignment, and reassignment problems in UMTS. We propose a new architecture for code management and, based upon this new architecture, a code assignment strategy, referred to as "crowded-group first strategy". Our system architecture and code assignment strategy represent significant improvements both in the time complexity and the maintenance complexity. Moreover, the code blocking probability of the crowded-group first strategy is competitive to that of the other strategies. In this paper, we also propose a new code reassignment strategy, called the "crowded-branch first strategy". The main objective of this reassignment strategy is to reduce reassigned call probability with low computation overhead and extend this strategy for the general case. In order to systematically analyze the performances of the code assignment strategy, we implement a simulator to analyze the code selection behavior and code blocking probability of each strategy. Moreover, we propose some new performance metrics, named "weighted code blocking", "reassigned call probability", and "ratio of actual code reassignments", in order to precisely measure the performance obtained by different strategies. From the simulation results, we show that our proposed strategies efficiently utilize the OVSF codes with low computation overhead.

For the reason of the orthogonal characteristic of the Orthogonal Variable Spreading Factor (OVSF) code tree in Wideband CDMA (WCDMA) systems, code blocking increases as traffic load (i.e. Erlang load) or the required rate increases. This causes inefficient utilization of channelization codes. Hence, how to efficiently manage the resource of channelization codes of the OVSF code tree in WCDMA systems is an important issue and has been studied extensively. There are two aspects to achieve efficiency including code assignment and code reassignment. In the aspect of code assignment, an efficient code assignment scheme reduces code blocking probability significantly. In the aspect of code reassignment, code reassignment results in several drawbacks, such as large overhead of computation, high complexity of codes moving, and long call setup time for a new request call, etc. Therefore, in this paper we focus on the first aspect of how to efficiently assign the channelization codes. Additionally, most researches did not consider the analysis of tree state with dynamic traffic load and their analysis lack of systematic call admission control (CAC) mechanism. Therefore, in this paper, we first propose the Markov decision process (MDP) based analysis to assign channelization codes efficiently. Next, we extend the MDP-based approach as the call admission control mechanism to maximize the system revenue while reducing blocking probability. Furthermore, a bit string masking algorithm is proposed to reduce the time complexity of tree managing and searching for available channelization codes. Numerical results indicate that the proposed MDP approach yields the best fractional reward loss, code blocking reward loss, and code blocking ratio as compared to that of other schemes, including the random, left most, and crowded first schemes.

Packet scheduling is the essential technique to provide QoS for multiple classes of service. Provided a minimum amount of bandwidth guarantee and a fair shared of residual bandwidth under a certain amount of power are the two major objectives of the packet scheduling in 3G networks. This paper presents two scheduling algorithms, MWF^2Q+ and MDRR, for multiple classes of service in the forward link of the UMTS network. These scheduling algorithms can allocate bandwidth in proportion to weights of flows sharing the channel under a certain amount of transmission power, and assign OVSF code to backlogged flows on a frame-by-frame basis. The MWF^2Q+ algorithm has better fairness properties while the MDRR algorithm requires less computational complexity. The efficiency and fairness properties are verified by our performance analysis. Our simulation results show that these two algorithms support multiple traffic sources with heterogeneous rate guarantees while fully utilizing the system bandwidth. The impact of self-similar traffic is also addressed in our simulations.

This paper presents two scheduling algorithms, MWF2Q+ and MDRR, for multiple classes of service over the same spectrum in the forward link of the UMTS network. These scheduling algorithms can allocate bandwidth in proportion to weights of flows sharing the channel, and assign OVSF code to backlogged flows on a frame-by-frame basis. The MWF2Q+ algorithm has better fairness properties while the MDRR algorithm requires less computational complexity and space complexity. The fairness properties of these scheduling algorithms are analysed in this paper. Our simulation results show that these two algorithms support multiple traffic sources with heterogeneous rate guarantees while fully utilizing the system bandwidth. The impact of self-similar traffic is also addressed in our simulations. Copyright © 2005 John Wiley & Sons, Ltd.

With traditional network architecture, it is hard to reach the requirement of elasticity deployment of the network. With virtual network architecture, although it is relatively easy to setup the network, but the system manager still needs tons of setup steps to accomplish his mission. Moreover, the setup steps of the solutions of virtual network are various, and give no guarantee to its consistency. In this paper, we introduce a new approach of network deployment mechanism, named "Mechanism of Automatic Deployment for Virtual Network Environment, MADV", to simplify the setup steps, and make it more friendly and ease to use for the newbies. We believe that with the MADV mechanism, the system manger can use it to deploy the hosts with low cost.

In the paper, we propose Hierarchical Deficit Round-Robin (HDRR) packet scheduling algorithm for multiple classes of service to pro-vide a fair share of residual bandwidth with lower computation complexity. We design HDRR based on the Deficit Round-Robin packet scheduling algorithm, and can distribute bandwidth in proportion to weights of flows sharing the bandwidth, and share the unused bandwidth to backlogged flows according to the hierarchical architecture. In order to realize the performance differences between the proposed scheduling algorithm and the other related scheduling algorithms, we implement the pro-posed scheduling algorithm in our simulation. The simulation results show that the proposed algorithm provides well QoS guarantees while fully utilizing the system bandwidth and low computation complexity.

Vehicle Navigation System (VNS) is a complicated and integrated system. A reliable vehicle navigation system should integrate the wireless communication technologies, positioning technologies, embedded computer, geographic information database, and so on. The major purpose of the chapter is to help understanding the architecture of vehicle navigation system. This chapter first introduces the system requirements and system analysis, and show the system platform of vehicle navigation system. The system platform can be divided into six components. There are the digital map database, positioning devices, map-matching process, route planning process, route guidance process, human-machine interface, and wireless communication interface. The design issues and system communication of these components are detail illustrated in the chapter. Finally, the authors also present some vehicle navigation systems proposed in the past few years, and show the difference of these systems. The aim of vehicle navigation system is to guide the vehicle along the optimal path from the starting point to destination. A reliable vehicle navigation system can reduce the traffic chaos in the city and improve the transportation delay. In order to achieve reliable vehicle navigation system, the detail system requirements, system analysis, and system architecture are shown in the chapter. Each component of vehicle navigation system is briefly illustrated, and the system communication is also described. The authors also present the architecture of the proposed vehicle navigation system, and show the difference of these systems. Therefore this chapter helps understanding the architecture of vehicle navigation system.

In 3G WCDMA, several multi-code assignment mechanisms have proposed to reduce the waste rate. Nevertheless, these methods bring two inevitable drawbacks including, high complexity of handling multiple codes, and increasing the cost of using more rake combiners at both the base stations and mobile nodes. Therefore, we propose an adaptive grouping code assignment herein to provide a single channelization code for any possible rate of traffic, even though the required rate is not powers of two of the basic rate. Based on the dynamic programming algorithm, the adaptive grouping approach forms several calls into a group. Then it allocates a subtree to the group and adaptively shares the subtree codes for these calls in the concept of time-sharing of slots during a group cycle time. Numerical results indicate that the proposed adaptive grouping approach reduces significantly the waste rate and thus increases the system utilization

This paper presents an integrated solution for code management and assignment problems. We propose a new architecture for code management, and based on this new architecture, a new code assignment strategy, referred to as 'crowded-group first strategy'. Our system architecture and code assignment strategy represent significant improvements in the time complexity and in the complexity of the storage operation. Moreover, the code blocking probability of the crowded-group first strategy can be as good as that of the crowded-first strategy. In order to systematically analyze the performance of the code assignment strategy, we implement a simulator to analyze the code selection behavior of each strategy. Moreover, in the numerical analyses, we propose a new performance metric, named 'weighted code blocking', in order to precisely measure the performance obtained by different strategies. From the simulation results, we show that our strategy efficiently utilizes the OVSF codes with the low computation overhead.

Since the orthogonal characteristic of the orthogonal variable spreading factor (OVSF) code tree in wideband CDMA (WCDMA) systems, code blocking increases as traffle load or required rate increases. This causes inefficient utilization of channelization codes. Hence, how to efficiently manage the resource of channelization codes of OVSF code tree in WCDMA is an important issue and has been studied extensively. Therefore, in this paper we focus on how to assign channelization code efficiently. Additionally, most researches did not consider the analysis of tree state with dynamic traffic load and lack of systematic call admission control (CAC) mechanism. Therefore, in this paper, we first propose the Markov decision process (MDP) based analysis to assign channelization codes efficiently. Next, we extend the MDP-based approach as the call admission control mechanism to maximize system revenue while reducing blocking. Numerical results indicate that the proposed MDP approach yields the best fractional reward loss and code blocking reward loss as compare to that of others, including the random, left most, and crowded first schemes, and the MDP-based CAC outperforms the capacity-based CAC significantly.

In the DS-CDMA (direct-sequence code-division multiple-access) cellular system, a call admission control (CAC) mechanism is needed to determine whether a new arrival user shall be accepted while the transmission quality of existing users can be guaranteed Furthermore, a handoff call shall have a higher priority than a new arriving call. Most of existing CAC mechanisms in the literature reserve a certain number of channels for handoff calls statistically. In this paper, the number of reserved channel should be adaptive to arrival rates of new calls and handoff calls, moving speed of user, call holding time, as well as the system capacity is shown. Therefore, in this paper, a CAC mechanism with adaptive channel reservation for handoff calls based on the Markov decision processes (MDP) is proposed. Simulation results show that the proposed scheme achieves better grade of service (GOS) of the system under various configurations.

In this paper we study the path-constrained-cost-optimized routing problem, which tries to minimize path cost while satisfying the QoS requirements of a connection. In previous research, each link of the network is associated with a set of QoS metrics, which represents the QoS metrics that can be provided by this link. However, in a real network, ATM switches are able to provide a finite number of QoS classes, instead of just one QoS class. Therefore, in this paper, we studied the path-constrained-cost-optimized routing problem where each link of the network is associated with several sets of QoS metrics. Our solution to this problem consists of two tasks: QoS decomposition and QoS-constrained least cost routing. We propose a greedy algorithm to decompose the end-to-end QoS constraint to local QoS constraints such that the path cost can be minimized. For QoS-constrained least cost routing, we first study three approaches for defining link costs. We then propose two routing algorithms for finding QoS-constrained paths.

Mobile IP provides a simple and scalable global mobility solution that supports users to access the Internet at anytime and anywhere. However, as the number or the velocity of the mobile IP users grows, the signaling overhead associated with the mobility management also grows. One of the solutions, cellular IP, a micro-mobility protocol, provides a seamless mobility support for semi-soft handoff and paging in limited geographical areas. In this paper, we propose a new micro-mobility management, which is an extension of cellular IP. Two special features are added in our scheme: page area group and pointer forwarding. Analytical model is developed to evaluate the reduction of signaling overhead of the proposed scheme. Simulation results are also conducted to verify our analysis. Our numerical results show that the proposed scheme can reduce the signaling overhead effectively.

Recent advances in embedded microsensing technologies and low-energy cost sensors have made wireless sensor networks possible. Object tracking is an important research of wireless sensor networks. However, most object tracking tree is constructed based on a predefined mobility profile. When the real object movement behaviors are very different to the predefined mobility profile, the object tracking tree performance will become worse. In the paper, we will propose a dynamic adaptation mechanism, referred to as “Message-Tree Adaptive (MTA)” procedure, to improve the object tracking tree when the predefined mobility profiles do not match. From the simulation results, the performance of the object tracking tree can be significantly improved, when the MTA procedure is performed.