Jyotsna Sengupta

3GPP LTE: The Future of Mobile Broadband

The mobile broadband technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with Orthogonal Frequency Division Multiple Access (OFDMA) based air interface technology. From technical perspective, fundamental goal of mobile broadband is to offer higher data rates with reduced latency. The third Generation Partnership Project (3GPP) presents the Long-Term Evolution (LTE) project in order to accommodate increasing mobile data usage and new multimedia applications. In the near future, with the recent progress made by technical specifications and vendor technology demonstrations LTE will emerge as successor to cellular systems as a broadband wireless solution. This paper provides an overview of 3GPP LTE including its history, features, technology, architecture and future. The technology components include OFDMA air-interface, Multiple-Input and Multiple-Output (MIMO) antenna technology and higher order modulation. The architecture includes Evolved Packet Core (EPC) and Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) components. This paper will concentrate to describe the main functions of the most important network elements. Also, the aim of this paper is to present the future potential of LTE which will make it an inevitable choice for wireless network operators around the globe.

High speed dynamic fault-tolerance

Multistage interconnection networks have been used as a favored ATM switch fabric. This paper analyzes the fault-tolerance and performance abilities of the proposed Phi network and compares it with its predecessor, the Omega network. The reduced numbers of stages of the designed MIN diminish the latency within the network markedly. The methods for routing permutations in the presence and absence of faulty components in both the networks have been analytically compared. The irregular nature of the Phi network allows 50% of the permutations to pass at the minimum path length of 2 whereas others pass at adaptable path length counting on the status of the path, largest being log/sub 2/N for a network of size N. The bandwidth of the new network shows optimal benefits. Bounds on reliability exhibit graceful degradation with time showing distinct gains over Omega where it reduces drastically, increasing the time between failures of the system. The comparison of these networks shows that irregular Phi network is a preferred choice to be used in the high-speed multiprocessor environment.

AODV and OLSR routing protocols for Wireless Ad-hoc and Mesh Networks

In this paper, we analysis and simulate the AODV and OLSR routing protocols for both Wireless Ad-hoc Network and Wireless Mesh Network. An Ad-hoc network is a collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration. Wireless Mesh Networks (WMNs) have recently gained a lot of popularity due to their rapid deployment and instant communication capabilities. WMNs are dynamically self-organized, self-configured and self-healed, with the nodes in the network automatically establishing an ad hoc network and preserving the mesh connectivity. Routing in both networks are nontrivial due to highly dynamic nature of the nodes. During simulation we consider three metrics i.e delay, network load and throughput of both networks.

Fault-tolerant routing in irregular MINs

Efficient and simple routing algorithms have been developed for two irregular MINs-namely, MFDOT and QT. Static routing provides full access for MFDOT whereas minimal multiple paths to reach the destination are provided through dynamic routing in QT networks. Multiple paths of varying lengths are available to route the data to the destination in irregular MINs. The path length is just 2 for a favourite memory module, as opposed to the identical path lengths used for regular MINs. This makes a marked difference in latency, throughput and cost of the network.

Permutation and reliability measures of regular and irregular MINs

Many regular and irregular indirect network topologies have been proposed that allow one to pass some fraction of permutations even in the presence of various faults, which depend largely on the reliability of the network. This paper studies the performance of a well-known augmented shuffle exchange network (ASEN) regular network, irregular network FT and the proposed new irregular network, the Smart Four Tree (SFT). It has been found that the reliability of the SFT network is best among these three networks, at the expense of increased cost, and that it also provides better permutation capabilities with reduced latency in the event of faults. Comparison of these networks, based on these metrics, exhibit the preferred performance of the irregular SFT over the regular ASEN and the irregular FT.

An Efficient Metamorphic Testing Technique Using Genetic Algorithm

Testing helps in preserving the quality and reliability of the software component thus ensuring its successful functioning. The task of testing components for which the final output for arbitrary input cannot be known in advance is a challenging task; as sometimes conditions or predicates in the software restrict the input domain Metamorphic testing is an effective technique for testing systems that do not have test oracles. In it existing test case input is modified to produce new test cases in such a manner that they satisfy the metamorphic relations. In this paper, we propose a genetically augmented metamorphic testing approach, which integrates genetic algorithms into metamorphic testing, to detect subtle defects and to optimize test cases for the component. We have further verified metamorphic testing results by all path coverage criteria information, which is generated during the metamorphic testing of the program and its mutants. The effectiveness of the approach has been investigated through testing a triangle type determination program.

Performance evaluation of Mobile Ad hoc Network routing protocols under various security attacks

Few characteristics of a Mobile Ad hoc Network, such as dynamic topology and shared wireless medium, pose various security challenges. This paper focuses on the performance investigation of reactive and proactive MANET routing protocols, namely, AODV and OLSR, under various the security attacks, where two types of attacks have been investigated. Network performance is evaluated in terms of end to end delay, retransmission attempts, network load and throughput, when a percentage of nodes misbehave. Simulation results show that under the passive attacks, proactive protocols perform well and under the active attacks, performance of reactive protocols is robust.

Performance analysis of static and dynamic fault-tolerant irregular networks

Notwithstanding the ever growing traffic on the Internet and the fundamental issue of decision on the fast and static network or the adaptable dynamic network, this paper presents the assessment of analytic performance of two irregular MINs, a static MIN-THN and a dynamic MIN-PHN. The performance has been analyzed on the basis of routing, fault-tolerance, the available bandwidth and cost. Results show that for the two irregular MINs, optimization of the performance and cost are essential for sustained fault-tolerant operation of the network. Whereas the static MIN gains on cost and speed, the dynamic MIN gains on fault-tolerance and reliable operation.

An Efficient Algorithm for Optimizing Base Station Site Selection to Cover a Convex Square Region in Cell Planning

It is gradually more significant to optimally select base stations in the design of cellular networks, as the customers stipulate cheaper and better wireless services. From a set of prospective site locations, a subset needs to be preferred which optimizes two critical objectives: service coverage and financial cost. Discovering the optimum base station locations for a cellular radio network is considered as a mathematical optimization problem. In the context of mobile communication, an efficient algorithm for the base-station placement problem is developed in this paper. The intention is to place a given number of base-stations in a given convex region and to assign range to each of them such that every point in the region is covered by at least one base-station and the maximum range assigned is curtailed. It is basically covering a region by a given number of equal radius circles where the objective is to minimize the radius. A computational method for finding good coverings of a square with equal circles is presented. An algorithm is designed that determines the optimal locations of base stations without performing an exhaustive search. The proposal will try to minimize the number of installed towers, makes tower’s location feasible, and provides full area coverage with an intention to reduce the overlapping.

Notice of Retraction Development and analysis of 3C-Model for software development lifecycle

Software Process model is a structured set of activities, which plays a fundamental role in the development of large-scale and complex software system. In Software development, process models are implemented to manage various concerns like cost, time, quality and changing requirements. The high failure rate in software development has shown that a new approach is required to meet the software development industry needs. This paper will present a phased model called 3C-Model which will be implemented for each phase of software development lifecycle and how it will help to manage all the concerns of effective software development.