Adaptive MIMO transmission in a realistic multicell scenario

Cochannel interference in multicellular radio systems is a challenge when full area coverage needs to be ensured. On the physical layer there exist several concepts to combat the interference. However, their performance in an orthogonal frequency division multiple access (OFDMA) system has not been thoroughly investigated yet. One promising technique is the employment of multiple antennas at the terminal side for the purpose of interference rejection. To increase the cell capacity further and under the assumption of a narrowband feedback channel, unitary beamforming can be used at the base station. We provide a performance evaluation of these techniques for an OFDMA system in the downlink and give quantitative results for the achievable capacity gains.