Recently, traffic in wireless networks has been increasing rapidly. To deal with this issue, it is important to utilize and coordinate multiple high-throughput small cell systems such as wireless local area networks (WLANs). In order to increase the number of high-throughput small cells easily, we now consider a system which consists of small outdoor cells constructed by access points set up indoors. To corroborate this system, field measurement of indoor-outdoor propagation in multiple environments is necessary. In this paper, we focus on the 3.5 GHz band which is used for small cells of long term evolution advanced (LTE-A) systems and 5G, and show the field measurement results of 3.5 GHz band indoor-outdoor propagation characteristics in multiple environments. The indoor-outdoor propagation characteristics of the 3.5GHz band are compared with the results of the 2.5 GHz band. The measurement results show the received power of the 3.5 GHz band signal to be 10-20 dB less than the results of the 2.5 GHz band signal. Moreover, the 3.5 GHz band extends to about 15-35m cell range while the 2.5 GHz band has about 35-95m when using quadrature phaseshift keying (QPSK) modulation with a 160MHz bandwidth. Hence, we acquired profitable data for a station layout design of 3.5 GHz band small indoor cells.