It has been demonstrated that distributed antenna systems (DASs) improve the transmission performance in indoor environment by reducing the radio transmission distance and providing macro diversity. In this paper, indoor DAS is proposed for high building environments. The objective is to provide high data rate transmission for indoor mobile users. The radio signal in high buildings can propagate through floors, hence, a mathematical propagation channel model is proposed in this work based on measurement results. The spectrum is reused among floors but it cannot be used within the same floor. Therefore co-channel interference exists between floors using the same frequency. Theoretical analysis is presented based on the mathematical channel model proposed. The performance of the system is evaluated in terms of bit error rate (BER) and the effect of the frequency reuse factor is presented. It is also demonstrated that the shape of the floor and the deployment of the RAUs have a significant effect on the BER performance.