Femtocell technology has been proposed to offload user data traffic from the macrocell to the femtocell and extend the limited coverage of the macrocell in mobile communications networks. In existing commercial femtocell/macrocell networks, a widely accepted solution to configure the location areas (LAs) is to partition the femtocells overlapped with a macrocell into small groups and to assign each group with a unique LA ID different from that of the macrocell. Such configuration can reduce the paging cost in the mobility management, but increases registration signaling overhead due to discontinuous coverage of femtocells. To reduce signaling overhead in the femtocell/macrocell network, we propose a delay registration (DR) algorithm that postpones the registration until the delay timer expires when the mobile station (MS) moves into the overlapped femtocell. Analytical models and simulation experiments are proposed to investigate the performance of the DR algorithm. Our analytical models are generally enough to accommodate various MS mobility behaviors. Our study can provide guidelines for the operators to set up a delay timer to reduce signaling overhead while sustaining the traffic offloading capability of the femtocell.

Mobile sensor networks (MSNs) have been widely deployed to provide a ubiquitous solution to real-time monitoring applications such as traffic data collection in vehicular ad-hoc networks (VANETs), ocean data collection in underwater sensor networks (UWSNs), and biodata collection in wireless body area networks (WBANs). One major issue for designing MSNs is the energy-validity trade-off, that is, the trade-off between the energy efficiency for mobile sensors (MSs) and the validity of sensing reports. In this article, we propose a novel mechanism, Energy-Efficient Distributedly Controlled Reporting (E 2 DCR), to mitigate the energy consumption for MSs in real-time monitoring applications while keeping the sensing report valid. In this mechanism, we design dynamic sleeping adjustment (DSA) algorithms to adjust an MS's sleeping period using a heuristic method to reduce energy consumption. We provide analytical models to evaluate the performance of E 2 DCR in terms of the power savings and report validity. It has been shown that with E 2 DCR, MSs can report with less energy consumption while satisfying delay constraints for real-time monitoring applications.

In Machine-to-Machine (M2M) communications, machines are wirelessly connected to accomplish collaborative tasks without human intervention, and provide ubiquitous solutions for real-time monitoring. The real-time monitoring application is one of the killer applications for M2M communications, where M2M nodes transmit sensed data to an M2M gateway, and then the M2M gateway can have real-time monitoring for each sensing region. In real-time monitoring application, the energy consumption for the M2M nodes to send sensed data to the M2M gateway is an important factor that significantly affects the performance of the system. In this paper, we first consider the energy consumption as well as the validity of sensed data to design either centralized or distributed energy-efficient reporting mechanisms. We then analyze the complexity of the reporting mechanisms. Simulation experiments are conducted to investigate the performance of the proposed mechanisms, and show that the distributed mechanism outperforms the centralized mechanism when the M2M nodes are mobile.

Internet services are now the major service platforms to provide services for all sectors of business and industries. To assure the correctness for concurrent data access, transaction-based Internet service is a well-accepted computation model. Because of the proliferation of networked devices and globalization, internet services can barely undertake any service interruption during any time of the day. However, transaction-base service model does not guarantee service continuity and could lower the quality of service in many circumstances. In this paper, we describe the design and implementation for service continuity technology to provide seamless online service upgrade for transaction-based Internet services. In particular, we report the implementation details on enterprise testbed. The developed mechanism is verified against on-line telecommunication web-services. The experimental results show that the recovery overhead is negligible and the mechanism is practical for deployment.

The service providers introduce new telecom services, which are managed by different Operations Support Systems (OSSs), to retain existing and attract new customers. The working group, TeleManagement Forum (TM Forum), proposed a unified network infrastructure, Next Generation Operations Systems and Software (NGOSS), as the standard interface between different OSSs to reduce the overhead for integration of sophisticated operating environments, and to shorten the time for launching new telecom services. For most of service providers, existing legacy OSSs are generally not compatible to the NGOSS framework. Due to the fact that those legacy systems have been working for a long time, modification or replacement of all systems incurs extra overhead for implementation and management. This paper proposes a systematic approach Middleware Architecture (MA) for migrating the existing legacy systems to the NGOSS compliant systems. We use the OSS through Java Initiative (OSS/J) Service Provisioning as an example to show how MA exercises for provision of new telecom service. Through the proposed approach, service providers can perform the migration in an incremental manner.

The great diversity of mobile sensor networks (MSNs) has emerged in different networks, including vehicular ad-hoc networks (VANETs), underwater sensor networks (UWSNs), and wireless body area networks (WBANs), which provide ubiquitous solutions for real-time monitoring. To prolong the network lifetime of MSNs, energy conservation for mobile sensors needs to be taken into consideration while we design the scheduling for MSNs. In this paper, we define the energy minimization problem for energy- aware transmission scheduling for MSNs, and prove that the problem is NP-hard. To have an optimal solution for the problem, we first formulate the problem as an Integer Linear Programming (ILP) problem, and then propose a greedy algorithm to approximate the solution of the ILP problem. We show that the computational complexity of the proposed greedy algorithm is low. We also propose a reporting mechanism to accommodate our greedy algorithm in MSNs. Simulation experiments are conducted to investigate the performance of the proposed reporting mechanism. Our performance evaluation shows that our mechanism has the mobile sensors transmit real-time sensed data with less energy consumption.

In wireless Multicast Broadcast Service (MBS), the common channel is used to multicast the MBS content to the Mobile Stations (MSs) on the MBS calls within the coverage area of a Base Station (BS), which causes interference to the dedicated channels serving the traditional calls, and degrades the system capacity. The MBS zone technology is proposed in Mobile Communications Network (MCN) standards to improve system capacity and reduce the handoff delay for the wireless MBS calls. In the MBS zone technology, a group of BSs form an MBS zone, where the macro diversity is applied in the MS, the BSs synchronize to transmit the MBS content on the same common channel, interference caused by the common channel is reduced, and the MBS MSs need not perform handoff while moving between the BSs in the same MBS zone. However, when there is no MBS MS in a BS with the MBS zone technology, the transmission on the common channel wastes the bandwidth of the BS. It is an important issue to determine the condition for the MBS Controller (MBSC) to enable the MBS zone technology by considering the QoS for traditional calls and MBS calls. In this paper, we propose two Dynamic Channel Allocation schemes: DCA and EDCA by considering the condition for enabling the MBS zone technology. Analysis and simulation experiments are conducted to investigate the performance of DCA and EDCA.

The Multicast Broadcast Service (MBS) zone technology is proposed to provide MBS with high QoS on Mobile Communications Networks (MCNs). An MBS zone consists of a group of Base Stations (BSs) synchronized to transmit the same MBS content using the same multicasting channel, which potentially reduces the time delay for Mobile Stations (MSs) to handoff between different BSs in the same MBS zone. However, significant time delay still incurs while MSs handoff between different BSs belonging to different MBS zones (i.e., the inter-MBS zone handoff). To reduce the possibility for the inter-MBS zone handoff, we may increase the size of an MBS zone (i.e., more BSs contained in an MBS zone), which may result in poor multicasting channel utilization. This paper proposes the OverLapping Scheme (OLS) for more flexible MBS zone configuration to get better performance for MBS in terms of QoS and radio resource utilization. We conduct propose the simulation experiments to investigate the performance for the original MBS zone technology (namely the Basic scheme), and the OLS scheme.

The mobile sensor networks (MSNs) have been widely deployed to provide an ubiquitous solution for time-sensitive applications in a specific area with low deployment cost. The monitoring area of an MSN can be divided into several sensing regions (SRs). In an SR, the mobile sensor (MS) is responsible for reporting the sensed data to the sink node. For the time-sensitive applications on MSN, the time is divided into multiple monitoring periods (MPs). During every MP, a sensing report transmission in an SR is invalid if the sensing report is generated before the beginning of the MP. In this paper, we propose a region-based reporting mechanism, namely Energy-Efficient Distributed-Control Reporting (E2DCR) mechanism, for the MSNs. During every MP, the E2DCR mechanism attempts to have only one MS transmit the sensing report in an SR, and the other MSs in the same SR can stay in the sleep mode for power saving. Simulation experiments are conducted to investigate the performance of the proposed mechanism. Our study shows that E2DCR can meet the delay constraint of the time-sensitive applications with less power consumption.

The indoor femtocell technology (known as femto BSs) with low power and low cost is proposed to provide comprehensive indoor wireless converge of macro BSs, which is known as the femtocell network. The Location Area ID for a femtocell is different from that for the macrocell that covers the femtocell, which results in frequent location update procedure (i.e., the location update cost increases) when the Mobile Station has a significant level of mobility between femtocells and macrocells. We propose the Cell Priority Transition (CPT) mechanism to reduce the location update cost for the femtocell network. The simulation experiments and analysis are conducted to investigate the performance of the CPT mechanism. Our study shows that the proposed CPT mechanism significantly reduces the location update cost for femtocell networks.

Abstract The Multicast Broadcast Service (MBS) zone technology is proposed to provide MBS with high QoS on Mobile Communications Networks (MCNs). An MBS zone consists of a group of Base Stations (BSs) synchronized to transmit the same MBS content using the same multicasting channel, which potentially reduces the time delay for Mobile Stations (MSs) to handoff between different BSs in the same MBS zone. However, significant time delay still incurs while MSs handoff between different BSs belonging to different MBS zones (i.e., the inter‐MBS zone handoff). To reduce the possibility for the inter‐MBS zone handoff, we may increase the size of an MBS zone (i.e., more BSs contained in an MBS zone), which may result in poor multicasting channel utilization. This paper proposes the OverLapping Scheme (OLS) and the Enhanced OverLapping Scheme (EOLS) for more flexible MBS zone configuration to get better performance for MBS in terms of QoS and radio resource utilization. We propose the analytical models for the original MBS zone technology (namely the Basic scheme), and the OLS scheme, which are validated against the simulation experiments. Based on the simulation results, we investigate the performance for the Basic scheme, the OLS scheme, and the EOLS scheme. Copyright © 2010 John Wiley & Sons, Ltd.