Haseeb Zafar

Performance evaluation of shortest multipath source routing scheme

Multipath routing in mobile ad-hoc networks allows the establishment of multiple paths for routing between a source-destination pair. It exploits the resource redundancy and diversity in the underlying network to provide benefits such as fault tolerance, load balancing, bandwidth aggregation and the improvement in quality-of-service metrics such as delay. Previous work shows that on-demand multipath routing schemes achieve better performance under certain scenarios with respect to a number of key performance metrics when compared with traditional single-path routing mechanisms. A multipath routing scheme, referred to as shortest multipath source (SMS) routing based on dynamic source routing (DSR) is proposed here. The mechanism has two novel aspects compared with other on-demand multipath routing schemes: it achieves shorter multiple partial-disjoint paths and allows more rapid recovery from route breaks. The performance differentials are investigated using NS-2 under conditions of varying mobility, offered load and network size. Results reveal that SMS provides a better solution than existing source-based approaches in a truly mobile ad-hoc environment.

A Survey of Quality of Service-aware Routing Approaches for Mobile Ad Hoc Networks

Abstract The provisioning of real-time applications such as voice and video over Mobile Ad Hoc Networks has been the subject of a significant amount of research due to increasing user demand. The efficient deployment of these services presents challenges due to capacity requirements and stringent delay constraints. Therefore, the design of an efficient and reliable routing scheme providing Quality of Service (QoS) support for such applications is a major objective. This paper provides an up-to-date survey of salient QoS routing approaches based on the interaction with the Medium Access Control layer. A brief outline of the operation, as well as the strengths and limitations of each scheme is presented. In addition, the open issues that must be addressed in the design of QoS-aware routing algorithms are discussed.

The Impact of Mobility Models on the Performance of Mobile Ad Hoc Network Routing Protocol

Abstract A mobility model represents nodes distribution and movement over the network. Several research works have shown that a selection of mobility model can affect the outcome of routing performance simulation in Mobile Ad Hoc Networks. Thus, a routing protocol may only be effective in a particular mobility model or scenario but performs inferiorly in another. As a result, analyses of routing protocol performance are often based on inadequate information leading to inaccurate argument and conclusion. In this paper, three different mobility models have been selected, where each of them is highly distinctive in terms of nodes movement behavior. In addition, a new measurement technique called probability of route connectivity is introduced. The technique is used to quantify the success rate of route established by a routing protocol. Extensive simulation runs are done and results are compared between each mobility model.

Partial-Disjoint Multipath Routing for Wireless Ad-hoc Networks

On-demand multipath routing in wireless ad-hoc networks can be effective in achieving load balancing over the network and in providing a degree of resilience to route failures. A shortest multipath source routing (SMS) protocol is proposed - a multipath extension to DSR - supporting multimedia applications. The protocol has two novel aspects compared to other on-demand multipath routing protocols: it achieves shorter multiple partial-disjoint paths and allows rapid recovery of route breaks. Simulation results show that SMS outperforms the competing protocols with respect to a number of key performance metrics.

A Survey on Femtocells: Benefits Deployment Models and Proposed Solutions

Femtocell networks are considered to be a viable option that can fulfill the demands of high speed voice and datatraffic for the indoor users. It uses the services of the existing broadband connection to connect to the operator corenetwork. The cellular network operators need to modify the existing single tier macrocell network in order to providethe services of femtocells to its users. In this paper, we present a survey on femtocell deployment. Various aspects offemtocell networks in a diverse domain are discussed. A detailed analysis of the previous approaches is given tohighlight their pros and the cons.

A Review of Techniques for the Analysis of Simulation Output

Abstract This paper first highlights common evaluation techniques used in wireless ad hoc networks. Specifically, it focuses on the discrete-event simulations. The paper further reviews methods that are used during the analysis of the generated results from discrete-event simulations. Steady-state detection, simulation time, and confidence intervals are considered.

A Complete Transmission Acknowledgement Scheme for VANETs

One of the distinct features of a Vehicular Ad Hoc Network (VANET) over a typical Mobile Ad Hoc Network (MANET) is its high processing capability due to no battery constraint. Reliable communication is very important in VANETs for providing safety messages, warning messages and other critical information for drivers assistance. However, congestion may occur due to continuous acknowledgement for providing reliability. Moreover, nodes might interact with each other for a very short duration of time due to different speeds and direction. Sending acknowledgements instead of actual data during that critical time will cause loss of packets. Realizing such constraints, we propose Complete Transmission Acknowledgement Scheme (CTAS) an efficient acknowledgement scheme that utilizes processing capability of vehicular nodes. In our proposed scheme, an acknowledgement is sent by the receiving node after the complete transmission of all the packets by the sending node. We further analyze the correctness and efficiency properties of the proposed Automatic Repeat reQuest (ARQ) scheme. When compared to present acknowledgement schemes, better throughput and packet delivery ratio is achieved.

M-AODV: Modified Ad Hoc On-demand distance vector routing scheme

The Ad Hoc On-demand Distance Vector (AODV) routing scheme is a widely used routing technique in ad hoc networks due to its low routing traffic overhead. However, the performance of the minimum hop routing used by AODV degrades significantly when the underlying system has routes that have high throughput and hop count. In this paper, we propose modifications to the routing metric and the route discovery mechanism of the AODVv2 scheme. The modified scheme is termed Modified-AODV (M-AODV). Simulation results reveal that the performance of the proposed scheme significantly improves in terms of key performance metrics when compared with AODV.

On-demand routing with unidirectional link using path loss estimation technique

Most on-demand Mobile Ad Hoc Network (MANET) routing schemes typically assume operation over symmetrical and bidirectional routing paths, both of which are not feasible due to the inherent heterogeneous properties of wireless devices. Radio links between a set of wireless devices may be asymmetrical and unidirectional as a result of factors such as high mobility, packet collisions due to interference and differences in terms of transmission power assigned to the devices. In this paper, an efficient routing scheme based on the path loss estimation technique is proposed. The proposed scheme effectively reduces the probability of selecting routing paths with unidirectional links by predicting the symmetrical properties of the link. In addition, nodes choose the link with the lowest path loss and estimate the received power in the reverse direction. As such, the number of unreliable links formed along the routing path can be minimized. The proposed scheme is compared against AODV-EUDA, AODV, and AODV-Blacklist, which provides support for unidirectional link detection and avoidance. Simulation results shows that the proposed scheme improves the number of packet transmitted by as much as 53%.

Evolving Dynamic Forecasting Model for Foreign Currency Exchange Rates Using Plastic Neural Networks

This work explores developmental plasticity in neural networks for forecasting the trends in the daily foreign currency exchange rates. With this work we achieved an efficient artificial neural network (ANN) based dynamic prediction model that make use of the trends in the historical daily prices of the foreign currency to predict the future daily rates while modifying its structure with the trends. The plasticity in ANN is explored to achieve a prediction model that is computationally robust and efficient. The system performance analysis prove that the prediction model proposed is efficient, computationally cost effective and unique in terms of its least dependency on the amount of previous data required for the future prediction. The prediction model achieved accuracy as high as 98.852 percent, in predicting a single days data from ten days data history, over a span of 1000 days (3 years). Further exploration demonstrated that when the problem domain for the network was changed to predict daily currency prices for multiple chunks of days a much better accuracy was achieved. This performance proved the robustness of the model proposed in this work for a modified problem domain.