Channel Feedback Techniques for Adaptive MIMO-OFDM Systems

📓 The new generation of wireless devices support higher data rates. Most of the new standards like HSPA utilize the spatial multiplexing of MIMO channels to achieve higher data rates, and exploit the diversity of MIMO channels to provide better performance. Hence there is an increased interest in the analysis of MIMO communication systems. The eventual objective is to achieve higher data rates in MIMO systems under the constraints of limited bandwidth and power. The radio spectrum is a scarce resource, and very expensive to license. Hence improved and efficient channel utilization techniques are requisite, that exploit the radio spectrum more proficiently. The multipath characteristics of the environment cause the MIMO channels to be frequency selective. For frequency selective deep fading, MIMO system remains ineffective. OFDM, a multicarrier transmission scheme, is well recognized for its potential for attaining high rate transmission over frequency selective channels. It can transform such a frequency selective MIMO channel into a set of parallel frequency-flat channels. Implementing space resources based on OFDM i.e., MIMO-OFDM provides higher data rate.