Measurement and Modeling of Temporal Variations of the Indoor Radio Channel

The results of Doppler spread and envelope fading based on CW measurements in the indoor radio channel are presented in this work. In this work, the temporal variations in the channel are caused by a moving receiver, or moving people in the vicinity of the transmitter and receiver. The result of the channel temporal variations is signal fading. The rate of fading can be measured by the Doppler spread. CW measurements were taken at different carrier frequencies from 14 to 14.5 GHz with an increment of 50 MHz. Different locations, antenna separation distances and positions (LOS or NLOS) were selected to collect the data. Each measurement consists of 2.5 seconds of temporal variations of the channel. The autoregressive spectral estimation method is used as a. tool to estimate the Doppler spread using CW measurements in the indoor radio channel. Results demonstrated that this method provided good estimates of the Doppler spread with a reasonable resolution and smoother spectrum than traditional spectrum estimation methods. The values of the Doppler spread under different measurement conditions are compared. Statistical analysis of envelope fading distributions based on the K-S and ChiSquare goodness tests and level crossing rates are presented. Those results can be used in future designs of wireless communication systems