Measurement and empirical modelling of root mean square delay spread in indoor femtocells scenarios

Abstract

A root mean square (RMS) delay spread model in indoor femtocell scenarios is proposed. The proposed model is based on extensive channel sounding of indoor stair, corridor and office environments. In this model, the RMS delay spread is described as a linear function of the path loss, and a normal stochastic variable is introduced and utilised to characterise the deviation of the measured RMS delay spread from the linear function. The proposed model can be used to simulate the RMS delay spread directly from extracted model parameters and the separation of the transmitting and receiving antennas. The closed-form formulas for fast calculating the mean value and variance of the RMS delay spread using some deterministic values, including the femtocell coverage distance and the parameters of the proposed model, are derived. The validity of the proposed model is verified by comparing the cumulative distribution functions and the statistical values of the measured and simulated RMS delay spread.