Adaptive modulation in MISO wireless systems with discrete low-rate power feedback

It is well known that the use of multiple-element antenna arrays improves the performance of wireless communication systems. In addition, link adaptation techniques, such as adaptive modulation, have shown to increase hugely the system spectral efficiency. Combining both techniques, we present an adaptive modulation scheme for multiple-input single-output (MISO) wireless downlink communication systems, with the particularity that a low rate feedback information channel is considered. First, we derive the capacity expression for such systems, with the supposition that the MISO propagation channel paths are uncorrelated. Next, a new proposed adaptive modulation scheme based on discrete feedback is applied to this MISO system. Finally, some performance simulations and conclusions are presented.