Indoor mobile communication systems are expected to provide significantly higher data rates and coverage than that offered by the conventional microcell system. However, the system performance is impaired by co-channel interference due to the need to reuse the limited available spectrum. To mitigate the effect of co-channel interference in this environment, distributed antenna systems (DASs) can be used to reduces the overall transmit power (and hence co-channel interference) by shortening the radio transmission distance between the transmitter and the receiver. In this paper, the impacts of DAS on uplink transmission in high-rise buildings is investigated, where remote antenna units (RAUs) are deployed on each floor throughout the building and connected to a central unit (CU) where received signals are processed. The performance of the system is analysed using a propagation channel model derived from multi-floor in-building path loss values retrieved from measurement data. For different system parameters, the average spectral efficiency is computed for a given maximum required BER, and parameters which yield the maximum spectral efficiency are identified. Numerical results obtained suggest that the proposed scheme can facilitate better use of the available radio spectrum, and provide higher data rates for indoor MTs.