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RISS 인기검색어
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- 저자 : Haseeb Zafar (검색결과 5 건)
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Wireless Machine-to-Machine Routing Protocol with Unidirectional Links
Megat Zuhairi,Haseeb Zafar,David Harle 한국산학기술학회 2011 SmartCR Vol.1 No.1
Wireless Machine-to-Machine (M2M) technology is a new approach to network communication that covers a wide area of applications. In this paper, we propose a reliable on-demand routing protocol for wireless M2M in Mobile Ad Hoc Network (MANET) applications such as telematics, healthcare devices, remote sensing for data mining, and building security monitoring systems. Generally, devices in such networks are typically battery powered and have wireless interfaces that could be connected to existing wireless infrastructures (e.g., IEEE 802.11) wireless networks. Devices on the network have different properties (i.e., transmission power) and thus communication may follow a sub-optimal path (i.e., asymmetrical path). We propose a reliable routing protocol that efficiently constructs a routing path in M2M with minimal route acquisition time and is capable of utilizing all possible link connectivity (i.e., unidirectional and bidirectional links). The performance differentials are investigated using NS-2. Our simulation results show that the proposed scheme achieves minimal end-to-end delay connection, higher goodput, and maximum reduction of normalized routing loads when compared with the competing Ad Hoc On-demand Distance Vector (AODV) routing protocol.
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Dynamic Reverse Route for On-Demand Routing Protocol in MANET
( Megat Zuhairi ),( Haseeb Zafar ),( David Harle ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.5
successful connection between a pair of source and destination nodes. An efficient routing protocol constructs routing path with minimal time, less routing overhead and capable of utilizing all possible link connectivity. In general, most on-demand MANET routing protocols operates over symmetrical and bidirectional routing path, which is infeasible due to the inherent heterogeneous properties of wireless devices. Simulation results show that the presence of unidirectional links on a network severely affect the performance of a routing protocol. In this paper, a robust protocol independent scheme is proposed, which enable immediate rediscovery of alternative route for a path blocked by a unidirectional link. The proposed scheme is efficient; route rediscovery is locally computed, which results in significant minimization of multiple route packets flooding. Nodes may exploit route information of immediate neighbors using the local reply broadcast technique, which then redirect the control packets around the unidirectional links, therefore maintaining the end-to-end bidirectional connection. The proposed scheme along with Ad Hoc On-demand Distance Vector (AODV) and AODV-Blacklist routing protocol is investigated over three types of mobility models. Simulation results show that the proposed scheme is extremely reliable under poor network conditions and the route connectivity can be improved by as much as 75%.
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A Survey of Cluster-based Routing Schemes for Wireless Sensor Networks
Gulbadan Sikander,Mohammad Haseeb Zafar,Ahmad Raza,Muhammad Inayatullah Babar,Sahibzada Ali Mahmud,Gul Muhammad Khan 한국산학기술학회 2013 SmartCR Vol.3 No.4
In recent times, wireless sensor networks (WSNs) have become progressively more attractive and have found their way into a wide variety of applications and systems because of their low cost, self-organizing behavior, and sensing ability in harsh environments. A WSN is a collection of nodes organized into a network. Routing is a vital technology in WSNs and can be roughly divided into two categories: flat routing and hierarchical routing. In a flat routing topology, all nodes have identical functionality and carry out the same task in the network. Nodes in a hierarchical topology do different tasks in WSNs and are usually arranged into clusters. In this paper, a survey on cluster-based routing schemes for WSNs has been done and comparisons made on the basis of performance factors such as latency, scalability, and energy awareness. Strengths and limitations of each scheme are presented, and open issues that must be addressed in the design of cluster-based routing algorithms are discussed.
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A Novel Approach for Blind Estimation of Reverberation Time using Gamma Distribution Model
Amad Hamza,Tariqullah Jan,Asiya Jehangir,Waqar Shah,Haseeb Zafar,M. Asif 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.2
In this paper we proposed an unsupervised algorithm to estimate the reverberation time (RT) directly from the reverberant speech signal. For estimation process we use maximum likelihood estimation (MLE) which is a very well-known and state of the art method for estimation in the field of signal processing. All existing RT estimation methods are based on the decay rate distribution. The decay rate can be obtained either from the energy envelop decay curve analysis of noise source when it is switch off or from decay curve of impulse response of an enclosure. The analysis of a pre-existing method of reverberation time estimation is the foundation of the proposed method. In one of the state of the art method, the reverberation decay is modeled as a Laplacian distribution. In this paper, the proposed method models the reverberation decay as a Gamma distribution along with the unification of an effective technique for spotting free decay in reverberant speech. Maximum likelihood estimation technique is then used to estimate the RT from the free decays. The method was motivated by our observation that the RT of a reverberant signal when falls in specific range, then the decay rate of the signal follows Gamma distribution. Experiments are carried out on different reverberant speech signal to measure the accuracy of the suggested method. The experimental results reveal that the proposed method performs better and the accuracy is high in comparison to the state of the art method.
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A Novel Approach for Blind Estimation of Reverberation Time using Gamma Distribution Model
Hamza, Amad,Jan, Tariqullah,Jehangir, Asiya,Shah, Waqar,Zafar, Haseeb,Asif, M. The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.2
In this paper we proposed an unsupervised algorithm to estimate the reverberation time (RT) directly from the reverberant speech signal. For estimation process we use maximum likelihood estimation (MLE) which is a very well-known and state of the art method for estimation in the field of signal processing. All existing RT estimation methods are based on the decay rate distribution. The decay rate can be obtained either from the energy envelop decay curve analysis of noise source when it is switch off or from decay curve of impulse response of an enclosure. The analysis of a pre-existing method of reverberation time estimation is the foundation of the proposed method. In one of the state of the art method, the reverberation decay is modeled as a Laplacian distribution. In this paper, the proposed method models the reverberation decay as a Gamma distribution along with the unification of an effective technique for spotting free decay in reverberant speech. Maximum likelihood estimation technique is then used to estimate the RT from the free decays. The method was motivated by our observation that the RT of a reverberant signal when falls in specific range, then the decay rate of the signal follows Gamma distribution. Experiments are carried out on different reverberant speech signal to measure the accuracy of the suggested method. The experimental results reveal that the proposed method performs better and the accuracy is high in comparison to the state of the art method.
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