This research paper describes the issues of bandwidth allocation, optimum capacity allocation, network operational cost reduction, and improve Internet user experience. Traffic engineering (TE) is used to manipulate network traffic to... more
This research paper describes the issues of bandwidth allocation, optimum capacity allocation, network operational cost reduction, and improve Internet user experience. Traffic engineering (TE) is used to manipulate network traffic to achieve certain requirements and meets certain needs. TE becomes one of the most important building blocks in the design of the Internet backbone infrastructure. Research objective: efficient allocation of bandwidth across multiple paths. Optimum path selection. Minimize network traffic delays and maximize bandwidth utilization over multiple network paths. The bandwidth allocation is performed proportionally over multiple paths based on the path capacity.
Global Navigation Satellite Systems (GNSS) Doppler measurements are commonly used for velocity-based relative positioning and aiding Inertial Navigation Systems (INS) in signal degraded environments. The aim of this paper is to... more
Global Navigation Satellite Systems (GNSS) Doppler measurements are commonly used for velocity-based relative positioning and aiding Inertial Navigation Systems (INS) in signal degraded environments. The aim of this paper is to characterise the Doppler measurements in GNSS harsh multipath environments. In multipath fading situations such as indoor and urban canyon environments, multipath components arrive to the receiver antenna from different paths and directions. These give rise to various Doppler shifts that cause errors in the velocity solution. In this work the Doppler measurements discrepancy characterised by Doppler spread in multipath environments is investigated. By assuming a ‘sphere of scatterers’ model and considering the antenna gain pattern, the theoretical Power Spectral Density (PSD) observed by a receiver is formulated. The theoretical findings are examined using two sets of measurements in dense multipath environments. Global Positioning System (GPS) live signals u...
In order to fulfil the increasing demands on capacity and coverage of mobile communication systems smart or intelligent antennas have been suggested. These antennas increase the spectral efficiency of a wireless system by using arrays of... more
In order to fulfil the increasing demands on capacity and coverage of mobile communication systems smart or intelligent antennas have been suggested. These antennas increase the spectral efficiency of a wireless system by using arrays of antenna elements to shape RF signals in particular directions. Generally, smart antennas can be divided into two approaches: switched multi-beam and adaptive. Adaptive antennas
In this paper the study has been carried out for finding the position of a mobile subscriber from a network independent brokers' point of view. As each mobile device monitors signal strength, this helps in assisting the network to... more
In this paper the study has been carried out for finding the position of a mobile subscriber from a network independent brokers' point of view. As each mobile device monitors signal strength, this helps in assisting the network to take timely handoff decisions. These signal ...
Multipath propagation can cause significant impairments to the performance of Global Navigation Satellite System (GNSS) receivers and is often the dominant source of accuracy degradation for high precision GNSS applications. Commonly used... more
Multipath propagation can cause significant impairments to the performance of Global Navigation Satellite System (GNSS) receivers and is often the dominant source of accuracy degradation for high precision GNSS applications. Commonly used time-of-arrival estimation techniques cannot provide the required estimation accuracy in severely dense multipath environments such as urban canyons. Multipath components are highly correlated and this results in a rank deficiency of the signal autocorrelation matrix. In this paper the Doppler spectrum broadening of the fast fading channel resulting from the motion of the receiver or surrounding objects is employed to decorrelate signal reflections for the purpose of high-resolution estimation of multipath delays through the subspace-based Multiple Signal Classification (MUSIC) technique. Specifically, delay-domain correlator outputs at different Doppler frequencies are combined to enhance the rank of the signal autocorrelation matrix. Simulation a...
In this paper the study has been carried out for finding the position of a mobile subscriber from a network independent brokers' point of view. As each mobile device monitors signal strength, this helps in assisting the network to... more
In this paper the study has been carried out for finding the position of a mobile subscriber from a network independent brokers' point of view. As each mobile device monitors signal strength, this helps in assisting the network to take timely handoff decisions. These signal ...
Wireless Sensor Networks (WSNs)have sensor nodes that sense and extract information from surrounding environment, processing information locally then transmit it to sink wirelessly. Multimedia data is larger in volume than scalar data,... more
Wireless Sensor Networks (WSNs)have sensor nodes that sense and extract information from surrounding environment, processing information locally then transmit it to sink wirelessly. Multimedia data is larger in volume than scalar data, thus transmitting multimedia data via Wireless Multimedia Sensor Networks (WMSNs) requires stick constraints on quality of services in terms of energy, throughput and end to end delay.Multipath routing is to discover multipath during route discovery from source to sink. Discover multipath and sending data via these different paths improve the bandwidth and decrease the end to end delay. This paper introduces an Energy Location Aware Routing Protocol (ELARP) which is reactive multipath routing protocol establishing three paths with awareness of node’s residual energy and distance. ELARP has experimented with NS2 simulator. The simulation results show that ELARP enhances QoS for multimedia data in terms of end to end delay and packet delivery ratio.
Deterministic channel models have been widely used in simulation and modeling of ad hoc network for a long time. But, deterministic channel models are too simple to represent a real-world ad hoc network scenario. Recently, random channel... more
Deterministic channel models have been widely used in simulation and modeling of ad hoc network for a long time. But, deterministic channel models are too simple to represent a real-world ad hoc network scenario. Recently, random channel models have drawn considerable attention of the researchers in this field. The results presented in the literature show that random channel models have a grave impact on the performance of an ad hoc network. A comprehensive investigation on this issue is yet to be available in the literature. In this investigation, we consider both deterministic and random channel models to investigate their effects on ad hoc networks. We consider two different types of routing protocols namely single path and multipath routing protocols. We choose Destination Sequence Distance Vector (DSDV), Dynamic Source Routing Protocol (DSR), and Ad-hoc On-Demand Distance Vector (AODV) as the single path routing protocols. On the other hand, we choose Ad-hoc On-Demand Multiple Path Distance Vector (AOMDV) as the multipath routing protocol. The results show that some single path routing protocol can outperform multipath routing protocol under both deterministic and random channel conditions. These results surprisingly contradict the popular claim that multipath routing protocol always outperforms single path routing protocol. A guideline for choosing an appropriate routing protocol for adhoc network has also been provided in this work.
The problem addressed is that of narrowband digital cellular communications in the presence of multipath and co-channel interferers having the same symbol rate and same overall signal characteristics as the desired source. For a given... more
The problem addressed is that of narrowband digital cellular communications in the presence of multipath and co-channel interferers having the same symbol rate and same overall signal characteristics as the desired source. For a given signal source, an algorithm is presented for blindly estimating the weight vector yielding the optimum SINR at the beamformer output. The instrumental quantity, denoted Sxx(f), is the Fourier transform of the expected value of the zero-lag autocorrelation matrix for one symbol period. The proposed scheme employs the PRO-ESPRIT algorithm to exploit the relationship between the timing offset and optimum beamforming weight vector for each source and the principal generalized eigenvalues and eigenvectors of the matrix pencil {Sxx(1/T0), Sxx(O)}, where 1/T0 is the symbol rate. Simulations are presented showing the rapid convergence of the algorithm and an improvement of several dB over the subspace-constrained Phase-SCORE algorithm
Abstract Power-line networks are promising mediums by which broadband services can be offered, such as Internet services, voice over Internet protocol, digital entertainment, etc. In this paper, an analysis of delay spread, coherence... more
Abstract Power-line networks are promising mediums by which broadband services can be offered, such as Internet services, voice over Internet protocol, digital entertainment, etc. In this paper, an analysis of delay spread, coherence bandwidth, channel capacity, and ...
We present a geometrical and time-variant wireless vector channel model with hyperbolically distributed scatterers for a macrocell mobile environment. This model is based on the assumption that the scatterers are arranged circularly... more
We present a geometrical and time-variant wireless vector channel model with hyperbolically distributed scatterers for a macrocell mobile environment. This model is based on the assumption that the scatterers are arranged circularly around the mobile station, whereby the distance between the mobile and the local scatterers and the distance between the local scatterers and the dominant scatterers are distributed hyperbolically. The proposed model allows investigation of beamforming aspects as well as space-time processing techniques. Simulation results for this model are presented and compared with the exponential model results.
In this paper the study has been carried out for finding the position of a mobile subscriber from a network independent brokers' point of view. As each mobile device monitors signal strength, this helps in assisting the network to... more
In this paper the study has been carried out for finding the position of a mobile subscriber from a network independent brokers' point of view. As each mobile device monitors signal strength, this helps in assisting the network to take timely handoff decisions. These signal ...
