Two promising candidates for beyond 3 rd generation (B3G) and 4G communication standards are multiple input multiple output (MIMO) and orthogonal frequency division multiple access (OFDMA) systems. OFDMA is a new technique that enables multiple users to transmit parallel data streams, allowing a much higher data rate than conventional systems, such as time division multiple access (TDMA) or code division multiple access (CDMA). Another research topic involving MIMO systems use antenna arrays at both the transmitter and the receiver. By using multiple antennas, the transmitter can adapt to the channel as it varies across time. This is accomplished by using a codebook of beamforming vectors which are known to both the transmitter and receiver. As the receiver acquires information about the channel, it calculates