Propagation Characterization of LEO/MEO Satellite Systems at 900-2100 MHz

This paper focuses on the propagation characterization of satellite communication systems in non-geostationary orbits at 900-2100MHz. An overview of available statistical propagation models for the mobile satellite communications channel is provided. Path loss equations for satellite communication systems in the range of 900-2100MHz for different environments and different probabilities of link closure are addressed. We also introduce a series of experiments being conducted to deepen understanding of these issues

An improved channel model for medical body area network device testing

For testing and validation of medical body area network devices the knowledge of the wireless channel is very crucial. Although this could be implemented by utilizing existing BAN channel models, their restriction to specific device usage scenarios and environments make them less appropriate. For this purpose, this thesis presents a methodology for an MBAN device testing by developing an improved channel model, which accounts for a room size and use case variability. The improved channel model is based on channel sounding, over the frequency band from 2.3 GHz to 2.5 GHz, performed for five different use cases defined based on body posture, movement, and orientation. In order to study the room size effect, the measurements have been carried out in three different office rooms and an anechoic chamber. The proposed channel model is composed of three components, which are modeled separately: the mean path loss, body shadowing, and multipath fading. The mean path loss is modeled as a distance log function, while the body shadowing is modeled statistically by a lognormal distribution, and the multipath fading by a Rician distribution. The impact of room size is mainly notified in the Rician K-factor value; whereas the effect of movement is notified in the lognormal parameter. Furthermore, the effect of body orientation and posture is represented in the path loss model parameters

LMSS propagation modeling at Virginia Tech

Recent efforts in the modeling of land mobile satellite systems are reported. These include descriptions of a simple model for prediction of fading statistics, a propagation simulator, and results from studies using the simulator. Predictions are compared to available measured data

Performance of turbo coded DS-CDMA systems in correlated and uncorrelated satellite communication channels

Word processed copy.Includes bibliographical references (leaves 82-88).This thesis aims at presenting the perfonnance of turbo codes in the correlated and uncorrelated satellite fading channel. Turbo codes are known to give very good perfonnance results in A WGN channels, especially for very large input message length codes or interleaver sizes. It can be shown that good perfonnance of the turbo codes can be achieved with small interleaver sizes in a satellite channel

A New Formula for the BER of Binary Modulations with Dual-Branch Selection over Generalized-K Composite Fading Channels

Error performance is one of the main performance measures and derivation of its closed-form expression has proved to be quite involved for certain systems. In this letter, a unified closed-form expression, applicable to different binary modulation schemes, for the bit error rate of dual-branch selection diversity based systems undergoing independent but not necessarily identically distributed generalized-K fading is derived in terms of the extended generalized bivariate Meijer G-function.Comment: Diversity schemes, selection combining, dual-branch selection diversity, binary modulation schemes, generalized-K (GK) model, composite fading, bit error rate (BER), and Meijer G-function distributio