Propagation Models

Performance analysis of umts network is of major interest, because of the WCDMA technique used in umts, which leads to an interference limited system with a dynamic cell capacity and load dependent cell coverage. The performance of umts network depends on sectorization; also, the coverage area depends significantly on the geografical nature and the propagatoin environment of the covered area. In this paper, the capacity and coverage of umts cellular network covering a densed urban area and suburban area are simulated for incrising amount of sectorization showing the number of users and coverage area gradually increased. For modelling the propagatoin, the cost-231 hata model has been used.

This paper concerns about the radio propagation models used for the upcoming 4 th Generation (4G) of cellular networks known as Long Term Evolution (LTE). The radio wave propagation model or path loss model plays a very significant role in planning of any wireless communication systems. In this paper, a comparison is made between different proposed radio propagation models that would be used for LTE, like Stanford University Interim (SUI) model, Okumura model, Hata COST 231 model, COST Walfisch-Ikegami & Ericsson 9999 model. The comparison is made using different terrains e.g. urban, suburban and rural area.SUI model shows the lowest path lost in all the terrains while COST 231 Hata model illustrates highest path loss in urban area and COST Walfisch-Ikegami model has highest path loss for suburban and rural environments.

The accuracy of the predicted Received Signal Strength (RSS) is the key issue in the mobile network design. In the last decades many models invented to predict the RSS in specific locations. One of the most famous models is Hata model, which is developed originally based on measurements done in Tokyo – Japan. The objective of this paper is to modify Hata model at frequency band 900 MHz to match the environments of Tripoli area, the capital of Libya. The modifications was based on real measurements of the RSS which were conducted in the concerned area. The modified model is expected to be used during the designing phase of the mobile networks in the future. The measurements is collected in five types of areas (Dense Urban, Urban, Dense Suburban, Suburban and Rural). The regression method is used to modify the Hata model parameters to match the real measured values of RSS within an acceptable range of accuracy. The RMSE (root mean square error) was calculated and used as an assessment factor for the modified module. The modified module gives 4.7 to 23.6 dB improvement in the accuracy of predicting the path loss, i.e. (46.5% to 66.4%) of Hata model values.

This paper concerns about the radio propagation models used for the upcoming 4 th Generation (4G) of cellular networks known as Long Term Evolution (LTE). The radio wave propagation model or path loss model plays a very significant role in planning of any wireless communication systems. In this paper, a comparison is made between different proposed radio propagation models that would be used for LTE, like Stanford University Interim (SUI) model, Okumura model, Hata COST 231 model, COST Walfisch-Ikegami & Ericsson 9999 model. The comparison is made using different terrains e.g. urban, suburban and rural area.SUI model shows the lowest path lost in all the terrains while COST 231 Hata model illustrates highest path loss in urban area and COST Walfisch-Ikegami model has highest path loss for suburban and rural environments.

This paper aims to show the effect of macrocellular network densification on the capacity, energy and cost efficiency. The presented results are based on radio propagation simulations that consider macrocellular network with different inter-site distances, i.e. different site densities, and also take into account the presence of indoor receiver points by varying outdoor and indoor receiver distribution. It is observed that as a result of densifying the network, the cell spectral efficiency reduces due to increasing level of inter-cell interference. However, as a result of densification, the network area capacity can be improved since the area spectral efficiency increases. Nevertheless, the densification efficiency decreases because of the reduction of cell spectral efficiency, especially when indoor receiver points are taken into account. The results hence indicate that densification of macrocellular network suffers from inefficiency which results in higher energy and cost per bit per Hertz, and thus calls for alternative methods to deploy networks, or alternatively, more sophisticated methods, such as base station coordination or inter-cell interference cancellation techniques, to be implemented for future cellular networks

Network simulation tools are frequently used to analyze performance of MANET protocols and applications. They commonly offer only simple radio propagation models that neglect obstacles of a propagation environment. The radio wave propagation model has a strong impact on the results of the simulation run. This work shows different radio propagation models into a simulation tool. The model is based on data of the simulation area in urban area. Consequently, we obtain different performance evaluation results. This paper gives insights on the effect of different propagation models for MANETs in indoor and outdoor environments and presents the parameters and the results of simulating using network simulator.

Wireless Sensor Networks (WSNs) is a strong candidate for smart grid applications, such as advanced metering infrastructure, demand response management, dynamic pricing, load control, electricity fraud detection, fault diagnostics, substation monitoring and control as well as automation of various elements of the power grid. The realization of these applications directly depends on efficiency of communication facilities among power grid elements. However, the harsh power grid environmental conditions with obstacles, noise, interference, and fading pose great challenges to reliability of these facilities to monitor and control the power grid. The purpose of this paper is to evaluate performance of WSNs in different power grid environments such as 500 kv substations, main power control room, and underground network transformer vaults. The power grid environments are modeled using a log-normal shadowing path loss model channel with realistic parameters. The network is simulated and performance is evaluated using packet delivery ratio, communication delay, and energy consumption. The simulation results have revealed that different environments have considerable impacts on performance of WSNs which make it suitable for most applications that need low data rate with low reliability requirements.

This paper concerns about the radio propagation models used for the upcoming 4 th Generation (4G) of cellular networks known as Long Term Evolution (LTE). The radio wave propagation model or path loss model plays a very significant role in planning of any wireless communication systems. In this paper, a comparison is made between different proposed radio propagation models that would be used for LTE, like Stanford University Interim (SUI) model, Okumura model, Hata COST 231 model, COST Walfisch-Ikegami & Ericsson 9999 model. The comparison is made using different terrains e.g. urban, suburban and rural area.SUI model shows the lowest path lost in all the terrains while COST 231 Hata model illustrates highest path loss in urban area and COST Walfisch-Ikegami model has highest path loss for suburban and rural environments.

Clock synchronization is critical to many sensor networks for the success of the application as well as energy efficiency. Achieving a global time frame through localized averaging of clock values for multiple rounds till convergence is a promising approach to clock synchronization due to the decentralized nature of computation coupled with scalability. However, it is not clear what power levels for all nodes would make the synchronization process energy-efficient. Large power levels lead to faster convergence but consume a lot of energy per round of synchronization. On the other hand, smaller powers consume little energy per round, but convergence is very slow requiring a lot of rounds to achieve synchronization. In this paper we look at the problem of finding a power assignment that achieves global clock synchronization in the most energy-efficient manner possible. We look at the problem through two dimensions; rate of convergence and energy consumed per round of synchronization. A centralized algorithm is presented that uses the path congestion of the induced communication graph to estimate which power assignments have good convergence properties and find one that minimizes the total energy to achieve clock synchronization. Our evaluation demonstrates that the power assignment derived from this algorithm is very energy-efficient and is applicable for wireless communication environments with various distance-power gradients. Further, we present a simple distributed algorithm which nodes can execute locally to derive energy-efficient power levels for global clock synchronization, and is especially useful in large-scale deployments.

This paper presents a measurement campaign conducted inside a Boeing 737-400 aircraft for the development of in-cabin wireless networks. The measurements were conducted in three different frequency bands in order to provide various services. It was found that the path loss factor along the aircraft corridor varies between 2.1 and 2.3 depending on frequency. The average K-factor in the aircraft aisle was found 12.3 dB, and the dynamic range of fading between 6.2 and 7.2 dB confirming the expectation of a physically stationary channel. In the seats of the aircraft the fading statistics are increased, in comparison with the aisle, with the dynamic range to be 14.9 dB in average. The average K-factor is reduced to 7.6 dB due to the obstruction of the direct path by the passenger seat. In all cases, the fading statistics correspond very well with Rician CDF.