Performane Improvement of Indoor and Outdoor Channel Models in Wireless Networks

A radio propagation model, also known as the radio frequency propagation model, is an empirical mathematical formulation for the characterization of radio wave propagation as a function of frequency, distance and other conditions .A single model is usually developed to predict the behavior of propagation for all similar links under similar constraints. Created with the goal of formalizing the way radio waves are propagated from one place to another, such models typically predict the path loss along a link or the effective coverage area of a transmitter.The channel model can vary with the antenna configuration in the transmitter and receiver (e.g., depending on single antenna system or multiple antenna system). Especially in the recent development of the multi-input and multi-output (MIMO) systems, acompletely different channel model is required to capture their spatio-temporal characteristics(e.g., the correlation between the different paths among the multiple transmit and receive antennas) [24]. This paper surveys different channel models used to characterise wireless indoor and outdoor environment. To develop and validate positioning algorithms under realistic conditions, an accurate knowledge of the propagation channel is significant. An outdoor-to-indoor channel model is proposed based on an extension of the geometry-based stochastic modeling approach to fulfill the requirements. The parameters of the outdoor-to-indoor channel model are extracted from two channel measurement campaigns. The proposed outdoor-to-indoor channel model is capable of accurately simulating the time variant channel. A comparison of the channel model with the channel measurement data is performed by comparing statistics.