Performance Improvement of Space-Time Block Coding Using Flexible Feedback Bits Over Rician Channels

Abstract

This paper addresses the concept of multiple-input multiple-output system using space-time block coding with the partial presence of channel state information at the transmitter. An efficient orthogonal space-time block coding system with 4-transmit and multiple receive antennas is developed. By employing an additional transmit antenna, the channel state information of 1, 2 or 3 feedback bits are utilized to improve the performance. The proposed scheme considers Rician flat fading channel with different line of sight power values. Moreover, the proposed system achieves full diversity order and a code rate of 3/4. In addition to that, the effect of different scales of partial feedback information on the performance is evaluated. Several examples of one and two receive antennas with different values of Rician factor and different number of feedback bits are simulated. Numerical results show that sizable performance improvement of the proposed scheme is obtained accordingly with increasing the number of feedback bits.