Improving Space-Time Code Performance in Slow Fading Channels using Reconfigurable Antennas

Space-time block codes typically only span a small number of time slots. However, error control coding spanning hundreds or thousands of symbol periods is often used with space-time coding. In this case, slow fading channels significantly degrade performance. In this letter, we show that performance can be significantly improved in slow fading conditions by using reconfigurable antennas. We propose switching the transmit antenna states during transmission so that the error control code experiences several different channel conditions over the transmission period. Hence, it can achieve higher diversity and the superior performance expected of a faster fading channel due to reconfigurable antenna state switching. If we also allow the receiver to select the reconfigurable receive antenna states based on channel energy, then an antenna state selection gain is also achieved.