Mobile Switching Research Articles

Review of Acknowledgment Based Techniques for Detection of Black Hole/Gray Hole Attacks in MANETs

In Mobile Ad hoc NETworks (MANETs) nodes communicate via wireless links, without any fixed infrastructure like base stations, central servers or mobile switching. Each node in MANET can act as a host or as a router. Due inherent characteristics like decentralization, self configuring, self -organizing networks, they can be deployed easily without need of expensive infrastructure and have wide range of military to civilian and commercial applications. But wireless medium, dynamically changing topology, limited battery and lack of centralized control in MANETs, make them vulnerable to various types of attacks. This paper focus on network layer packet dropping attacks – Black Hole & Gray Hole attacks in Dynamic Source Routing (DSR) based MANETs and discuss various pros and cons of acknowledgement based techniques for detection of above said attacks.

Structural Basis for the ATP-Induced Isomerization of Kinesin

Kinesin superfamily proteins (KIFs) are microtubule-based molecular motors driven by the energy derived from the hydrolysis of ATP. Previous studies have revealed that the ATP binding step is crucial both for the power stroke to produce motility and for the inter-domain regulation of ATPase activity to guarantee the processive movement of dimeric KIFs. Here, we report the first crystal structure of KIF4 complexed with the non-hydrolyzable ATP analog, AMPPNP (adenylyl imidodiphosphate), at 1.7Å resolution. By combining our structure with previously solved KIF1A structures complexed with two ATP analogs, molecular snapshots during ATP binding reveal that the closure of the nucleotide-binding pocket during ATP binding is achieved by closure of the backdoor. Closure of the backdoor stabilizes two mobile regions, switch I and switch II, to generate the phosphate tube from which hydrolyzed phosphate is released. Through the stabilization of switch II, the local conformational change at the catalytic center is further relayed to the neck-linker element that fully docks to the catalytic core to produce the power stroke. Because the neck linker is a sole element that connects the partner heads in dimeric KIFs, this tight structural coordination between the catalytic center and neck linker enables inter-domain communication between the partner heads. This study also revealed the putative microtubule-binding site of KIF4, thus providing structural insights that describe the specific binding of KIF4 to the microtubule.

A high performance link layer mobility management strategy for professional private broadband networks

In this paper, we present an innovative approach to solving the mobility management problem in the context of professional private broadband networks in the vehicular scenario. These heterogeneous communication networks are commonly deployed and managed by mission-critical organisations with the aim of supporting their specific and highly demanding services. Taking advantage of the specific characteristics of these networks, we propose to solve the mobility problem at Layer 2. This way, the mobility management overhead is reduced compared to solutions that operate at Layer 3 or above and therefore, shorter handover delays and better end-to-end application performances are achieved. The core element of our proposal is an intelligent mobile switch that makes use of the services provided by the IEEE 802.21 protocol to enhance vertical or heterogeneous handover performance. To validate our approach, we have developed a prototype implementation of the designed mobile switch with IEEE 802.11 and IEEE 802.16 support. Using this mobile switch implementation, we have carried out a set of experiments over a real testbed and measured some key indicators to assess the mobility management process. The obtained results show that our handover strategy comfortably meets the requirements of the ITU-T Y.1541 recommendation for highly demanding applications and ITU-R report M.2134 for high-speed handover. To the best of our knowledge, our contribution is the first proposal that solves the mobility management problem at Layer 2 while addressing the multi-access technology context in the vehicular professional private network scenario.

Sliding window method based on enhanced throughput prediction for improving GSM network efficiency by reducing HLR-VLR transitions

The throughput of a global system for mobile GSM communications network is to be maximised for meeting effectively and efficiently the service requirements of ever increasing mobile subscriber's base. The period of temporary storage of subscribers' profiles in visitor location register VLR at a mobile switching centre MSC affects the throughput of GSM network. This research study proposes a sliding window method for determining the storage period of profiles in VLR that maximises the throughput of GSM network. The proposed method proves to be better than the existing set intersection method.

OPTIMIZATION OF CHANNEL ALLOCATION ALGORITHM FOR HOT SPOT CELLS IN WIRELESS NETWORKS

Dense deployment of cellular networks is leading to scarcity of communication bandwidth or what we call as channel. If compared to its wired counterparts, wireless cellular network have limited number of channels available, which gives rise to problem of efficient channel allocation. Here, in this piece of work, the main objective is to put an effort to improve existing channel allocation scheme. In earlier existing hybrid allocation scheme, the base station notifies about the hot-spots to the Mobile Switching Centre (MSC) and if MSC has available channels in its central pool then it satisfies the request. Now, the novelty of this work starts where central pool gets exhausted and request of channels from base station (BS) still arrives and is served by returning the unused channels by different cells back to MSC on its request. The simulation of this approach is expounded and evaluated over OMNeT++ in a scenario with fixed channel allocation and hybrid approach by varying the proportion of dynamic channels to total number of channels available and the effectiveness is evaluated in terms of Call blocked and Call dropped versus System load.

An Index-Based Location Management Scheme for PCS Network

Location management provides the guarantee to deliver a call to mobile user during the mobility of user and it is a key challenge in wireless cellular networks. In this paper, we are introducing a new index-based location management scheme. It is based on indexing of location update information at the home agent of network. A tuple of index will keep track of range of location update information and corresponding thread of it, connected to stack of information table. To register a new mobile user, the mobile switching centre will generate a new identification number with the help of mobile switching centre identification number and temporary mobile subscriber identity of subscriber. If, the identification number is with in the range of index then, the Care of Address of mobile subscriber is added to information table else, the index will be reconstruct based on new range of identification number. It has been observed that in proposed technique, the call setup delay and network overheads is reduces over the limitation of minor increment of registration delay. The analytical model and numerical result represents the effectiveness of proposed scheme over the existing schemes.

A FUZZY LOGIC BASED HANDOFF APPLICATION ON OPEN-SOURCE PLATFORM

Handoff, in wireless networks, occurs when a mobile terminal switches from one network to another. While moving out from one point to another, mobile terminals may come across different types of networks each has specific characteristics that need to be considered when choosing the best candidate. Selection of the optimum access point is a challenge that impacts the overall network stability, quality of service provisioning, resource utilization, and user satisfaction. Nowadays, there are many mobile platforms for mobile terminals. Android, Google`s open-source framework, consists of an operating system and software stack for developing applications on mobile devices. The Android framework provides capabilities of the Linux kernel and its SDK provides the tools and APIs for developing applications on the Android platform using the Java programming language. In this study, we have developed an Android application with a user friendly graphical interface, which switches the connection between IEEE 802.11b and 802.11g Wi-Fi hotspots using its fuzzy logic based handoff decision making module. The results show that desired performance results could be obtained with the software developed.

Collaborative Caching in Wireless Video Streaming Through Resource Auctions

Recent advances in wireless communications and mobile networking have dramatically increased the popularity of multimedia services for mobile users, with wireless video streaming at their fingertips. To facilitate efficient acquisition of video content, proxy caching has been widely used by wireless service providers (WSPs), which typically deploy cache servers at mobile switching centers (MSCs). However, capacity provisioning of cache servers is challenging, given the dynamic user demands and the limited cache server resources. With increased densities of wireless service deployment, it is increasingly common that mobile users are covered by more than one WSP within an area. This brings opportunities of a collaborative caching paradigm among the cache servers deployed at different MSCs. In this paper, we explore the benefits of collaborative caching in wireless streaming services, addressing both challenges of incentives and truthfulness of selfish WSPs. We propose a collaborative mechanism that maximizes the social welfare in the context of Vickrey-Clarke-Groves (VCG) auctions, in which cache servers cooperate in the trading of their resources in a self-enforcing manner. Experimental results demonstrate that superior performance can be achieved with respect to the quality of video streaming.

Guest editorial: hybrid systems, part II

We consider it a great privilege to introduce this two-part issue on Hybrid Systems to Discrete Event Dynamic Systems: Theory and Applications. Hybrid dynamical systems constitute an abstract modeling framework for systems with bi-layer dynamics: time-driven dynamics at the lower layer, and discrete-event dynamics at the upper layer. This framework provides useful analysis techniques and simulation tools for planning and control of systems in several application areas such as mobile robotics, automotive powertrains, switching circuits, manufacturing, and telecommunications. Consequently, hybrid systems have been extensively investigated by our research community, with emphases on the problems of stability, observability, control, and optimization. The hybrid-systems framework is diverse and includes linear and nonlinear models, deterministic and stochastic systems, and centralized systems as well as distributed networks. One of their unifying themes is the bi-level structure of their dynamics, and the exploration of the interactions between their time-driven dynamics and discrete-event dynamics has been a focus of extensive research. The purpose of this special issue is to bring together papers representing some of the main standing problems in the area of hybrid systems. The contributions comprising the first part of the special issue are summarized in the following paragraphs. The first paper in this issue, On Fluidization of Discrete Event Models: Observation and Control of Continuous Petri Nets, by M. Silva, J. Julvez, C. Mahulea, and C.R. Vazquez, provides a survey of hybrid Petri networks. It starts with a tutorial on the broad topic of fluidization of discrete event dynamic systems and its use in circumventing the problem of the state-space explosion. It then considers Petri networks in detail, where it describes how fluid and hybrid models can be used in

Research of Mobile IPv6 Switch

Traditional mobile IPv6 switching will produce transmission delay,to the mobile communication a great deal of trouble. This switching protocol in mobile IPv6 based on the three improved switching protocol,By the four sides of switching delay、data loss,、signaling load、Complexity to compare,get the most appropriate mobile switching technology.

An efficient metric-based (EM-B) location management scheme for wireless cellular networks

In the current era, the wireless cellular network is gaining much attention in the network mobility for qualitative service. Towards enhancing the QoS and narrowing the dilemma of network management (location management) an efficient metric-based location management technique is introduced in this paper to capture the current location of mobile subscribers. The attributes of this technique are based on metrics calculation and location management message routing path determination. First, the current mobile switching center will calculate the shortest metric-based path between current and master (previous) location of mobile terminals (user), thereafter it performs the location management procedure through the optimal suggested path by the mobile switching center. This proposed technique will reduce the signaling cost, registration delay, call setup delay, network overheads and total location management cost. The proposed analytical model checks the scalability and effectiveness of proposed system over certain attributes and a comparison is made with the existing available techniques.

Building better backhaul

Cellular networks have always relied on connections between each basestation and a mobile telephone exchange or switching centre (MtX/MsC) to 'backhaul' phonecalls and mobile data to the rest of the network. Backhaul has for years been taken for granted by all but a relatively small group of technicians and engineers who manage, maintain, and develop the time-divisionmultiplexing (TDM) systems that provide this vital connectivity.

라그랑지안 기반의 휴리스틱 기법을 이용한 셀룰러 모바일 네트워크의 설계

Cellular network is comprised of several base stations which serve cellular shaped service area and each base station (BS) is connected to the mobile switching center (MSC). In this paper, the configuration modeling and algorithm of a cellular mobile network with the aim of minimizing the overall cost of operation (handover) and network installation cost (cabling cost and installing cost of mobile switching center) are considered. Handover and cabling cost is one of the key considerations in designing cellular telecommunication networks. For real-world applications, this configuration study covers in an integrated framework for two major decisions: locating MSC and assigning BS to MSC. The problem is expressed in an integer programming model and a heuristic algorithm based on Lagrangian relaxation is proposed to resolve the problem. Searching for the optimum solution through exact algorithm to this problem appears to be unrealistic considering the large scale nature and NP-Completeness of the problem. The suggested algorithm computes both the bound for the objective value of the problem and the feasible solution for the problem. A Lagrangian heuristics is developed to find the feasible solution. Numerical tests are performed for the effectiveness and efficiency of the proposed heuristic algorithm. Computational experiments show that the performance of the proposed heuristics is satisfactory in the quality of the generated solution.

A mechanism of carbapenem resistance due to a new insertion element (ISPa133) in Pseudomonas aeruginosa.

This study explored the evolutionary mechanism by which the clinical isolate PA110514 yields the imipenemresistant derivative PA116136. Both isolates were examined by PFGE and SDS-PAGE, which led to the identification of a new insertion sequence, ISPa133. This element was shown to have distinct chromosomal locations in each of the original isolates that appeared to explain the differences in imipenem susceptibilty. In strain PA110514, ISPa133 is located 56 nucleotides upstream of the translational start codon, which has no effect on expression of the porin OprD. However, in strain PA116136 ISPa133 it is located in front of nucleotide 696 and, by interrupting the coding region, causes a loss of OprD expression, thus conferring imipenem resistance. In vitro experiments mimicking the natural conditions of selective pressure yielded imipenem-resistant strains in which ISPa133 similarly interrupted oprD. A mechanism is proposed whereby ISPa133 acts as a mobile switch, with its position in oprD depending on the degree of selective pressure exerted by imipenem.

Optimal Mobile Switching Center Positioning and Cells Assignment Using Lagrangian Heuristic

This paper deals with the configuration of a wireless network with the aim of minimizing the overall cost of both operation and network installation. The trade-off between the operation cost and the installation cost is the key consideration when designing cellular telecommunication networks, and can save costs and improve the performance of the network. In this paper, we propose an integrated framework for selecting Mobile Switching Center (MSC) among the candidate MSCs and assigning Base Stations (BSs) to the selected MSCs with the objective function of minimizing the cost of MSC setup, BS to MSC cabling, as well as the cost of handover. Capacity constraint for the selected MSC is also considered in the problem. The problem is expressed in an integer programming model and the Lagrangian relaxation method is proposed to solve the problem by dualizing some constraints. The Lagrangian relaxed problem is decomposed into subproblems that can be resolved optimally. The Lagrangian heuristic algorithm is suggested to find feasible solutions to the original problem. Computational experiments are performed to test the effectiveness and efficiency of the proposed heuristic algorithm. In the experiments, Lagrangian bounds on the optimal solution are used to show the effectiveness of the algorithm. The results of the proposed algorithm are also compared with those of some conventional meta-heuristics, Tabu search (TS) and Genetic algorithm (GA). The computational experiments show that the performance of the proposed heuristics is satisfactory in both the speed and the quality of the solution generated.

Security Aspects in Mobile Ad Hoc Network (MANETs): Technical Review

Mobile Ad hoc networks (MANETs) are a new paradigm of wireless network, offering unrestricted mobility without any underlying infrastructure such as base station or mobile switching centers. Basically ad hoc network is a collection of nodes communicating with each other by forming a multi-hop network. In a mobile ad hoc network, it is much more vulnerable to attacks than a wired network due to its limited physical security, dynamically changing network topology, energy constrained operations and lack of centralized administration. Since all the nodes in the network collaborate to forward the data, the wireless channel is prone to active and passive attacks by malicious nodes, such as Denial of Service (DoS), eavesdropping, spoofing, etc. The intent of this paper is to investigate the security goal, security challenges and different types of active and passive attacks on MANETs.

Switching cost minimization in the IEEE 802.16e mobile WiMAX sleep mode operation

AbstractTo prolong the battery lifetime, it is important to continue designing a better energy efficient mechanism for different mobile technologies. Most of the existing works on the IEEE 802.16e sleep mode operation focus on the decision making before a mobile station switching to sleep mode state. The correlation of the decision is mainly on when and how to sleep based on the traffic demands. After the mobile station is switched to sleep mode, the deactivation of it mainly depends on new incoming traffic regardless of the actual amount. Truly, frequent switching can increase the energy cost on the mobile station, which can significantly reduce the battery lifetime. To minimize the switching frequency, we propose a novel approach to resolve this issue by making a heuristic decision during the listening interval. With this aim, we propose a real‐time heuristic algorithm, WAKSLP_DECISION, to accommodate our target. Three main decision criteria are analyzed and designed, namely the probability of buffer overflow, expected delay violation, and battery lifetime expiry, to achieve our goal. We verify the energy consumption performance with simulation experiments to validate our proposed scheme. The result shows that our scheme performs 25–30% better compared with the original standard in terms of energy consumption. We believe this algorithm is practical and implementable without changing the original standard, which can contribute both in the research community and industrial development. Copyright © 2009 John Wiley & Sons, Ltd.

Multi home agent and pointer-based (MHA–PB) location management scheme in integrated cellular-WLAN networks for frequent moving users

In this paper, we introduces a multi home agent and pointer-based location management scheme. Multi home agent preserves the location information for different wireless technologies (Universal Mobile Telecommunication system, Wireless Local Area Networks) and maintains a cache for the location information of mobile host. In addition, an index based call delivery system has been proposed. The performance comparisons and numerical analysis are helpful to find out the efficiency and effectiveness of the proposed system, with respect to existing location management techniques (single registration scheme, and dual home agent scheme). It has been observed that the registration cost, call setup delay, registration delay and overhead at mobile switching center are reduces in the proposed MHA–PB scheme.

Practical Implications for Backhaul: A View into the National Broadband Plan [MicroBusiness

The Federal Communications Commission (FCC) announced an aggressive agenda for implementing key aspects of the nation's first-ever National Broadband Plan (NBP). The NBP focuses in multiple places on backhaul, which is the transport of voice, video, and data traffic from a wireless carrier's or public safety network's base station (or cell site) to its mobile switching center (MSC). Backhaul appears in the NBP in both direct and nuanced ways.

Secure cognitive mobile hotspot

The paper presents a novel consumer device that acts as a cognitive mobile hotspot to provide ubiquitous secure wireless WAN and LAN connectivity while on the move. The mobile hotspot acts as a gateway and integrates VHF/UHF radios with multiple wireless WAN and LAN technologies. The device supports GPRS, EDGE, WCDMA, CDMA2000 and WiMAX as WAN interfaces for long range communication and 802.11, Bluetooth and VHF/UHF interfaces for short range communication. The cognitive controller in the device seamlessly switches the WAN interfaces to provide optimum connectivity and Quality of Service parameters to the LAN devices and VHF/UHF radio links. In applications where nodes are fully mobile, the cognitive mobile hotspot acts a centroid by adjusting its position dynamically and provides a complete mobile backbone for optimum connectivity to mobile devices in a heterogeneous environment. The unique device opens a new paradigm of mobile backbone and seamless switching between multiple wireless broadband technologies and integration of wireless LAN and VHF/UHF interfaces. The device finds applications in vehicle area networks, mobile branch offices, mobile healthcare, media & broadcasting, sporting competitions, trade fairs, exhibitions and mission critical applications like flood relief operations and disaster recovery.