Abstract: An approximate expression of bit error rate (BER) is derived for a circular cell distributed antenna system with space-time block coding based on Alamouti's scheme and utilizing binary phase shift keying (BPSK) modulation. The analysis is carried out on considering the effects of path loss, log-normal shadowing, multipath fading and background noise. A simulation is carried out under the condition of two transmit and one received antennas, single-path Rayleigh fading channels, antenna spacing of 200 m, and standard deviation of shadowing of 8 dB. The simulation results show that, the numerical results match the simulation results well, and at the BER of 3×10-1, the proposed method is superior by about 1.4 dB to the traditional methods in bit signal-to-noise ratio.