Outdoor/indoor propagation experiment for estimation of interference to satellite caused by cellular phone in satellite/terrestrial dual-mode frequency-shared cellular phone system

This paper describes the overview and data analysis of the outdoor/indoor propagation experiment planned to estimate the interference level in hybrid satellite/terrestrial cellular phone system. The system, which is a dual-mode frequency-shared cellular phone system, needs fundamental interference level data in the system feasibility study. This work focuses on the estimation of interference level to satellite caused by the cellular phone using terrestrial link, which varies depending on the location of the cellular phone user. The experimental system using an IMT-2000 cellular phone, a continuous wave (CW) transmitter, and a pseudo satellite (PS) located on top of a 50-m tower which mimics the interference situation of the hybrid cellular phone system. In the experiment, dynamic range of measurement is enhanced and number of cellular phone location is increased compared with our previous fundamental experiment held in 2009. Measurement was carried out at over six-hundred positions of cellular phone in outdoor/indoor locations in the office building site. Measured transmit powers of cellular phone and received powers of CW at the PS as well as the estimated received powers of cellular phone transmit wave at the PS are analyzed to extract the difference of trend between outdoor/indoor locations. Analysis of the estimated received power of cellular phone transmit wave at the PS indicates that the estimated PS received power of indoor cellular phone transmit wave is lower than that of outdoor cellular phone transmit wave (differences of average and median values are 8dB and 10dB, respectively). These results are useful in the estimation of the interference level to satellite caused by cellular phone using terrestrial link in the hybrid cellular phone system.