On the Capacity of Correlated MIMO Channels for Informed and Uninformed Transmitter at Different Antenna Configurations

Abstract

Modern wireless systems continue to demand higher data rates and better reliabilities. These demands can be met by using multiple antennas at both sides of the wireless link i.e. Multiple-Input Multiple-Output (MIMO). The capacity of MIMO correlated Rayleigh channels for different antenna configurations with and without channel knowledge (CSI) at the transmitter is simulated. When CSI is available at the transmitter (i.e. informed transmitter), waterfilling algorithm is used to allocate the power among the transmitter antennas. Simulations show that capacity is improved significantly when CSI is known at the transmitter. It also shows that the lack in channel knowledge (i.e. uninformed transmitter) can be compensated for by increasing the number of antennas in the receiver (Mr). When the number of antennas in the transmitter is larger than those in the receiver, using waterfilling becomes necessary to get the optimum capacity.