Pilot Arrangement for Achieving Full Frequency Reuse in Downlink Distributed OSTBC

摘要

A pilot arrangement is proposed for downlink orthogonal space-time block coding with distributed antenna systems, with which the same carrier frequency can be used by all transmit antennas. In our proposed method, transmit antennas are located at the three vertices of a equilateral triangle in a large region, and based on this architecture, the pilot symbols used by adjacent antennas are orthogonal in both time and frequency domains. Analytical expression for the mean squared error of channel estimation is derived to optimize the pilot arrangement. A simulation is carried out under the condition of three transmit and two receive antennas, multipath Rayleigh fading channels, and antenna spacing of 500 meters. The simulation results show that, at the area averaged mean square error of 10~(-2), the proposed method outperforms the traditional one by about 1.2 dB in bit signal-to-noise ratio.