Detection and channel estimation in 8 × 8 MIMO-OFDM

Higher data rate and lower power consumption requirements set new challenges for implementation of multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) re-ceivers. Simple detectors have low complexity and power consumption, but the performance is worse than with more complex detectors. Therefore the detector can be adapted to suit the channel conditions to minimize the power consumption while satisfying the quality of service requirements. The performances of the linear minimum mean-square error (LMMSE) detector and the K-best list sphere detector (LSD) in a long term evolution (LTE) system are compared. We also investigate least squares (LS) channel estimation performance with different mobile speeds and correlation scenarios. Theoretical complexities of the detectors are also given. In the 4 × 4 system, high order modulation and bad channel estimate impacts the performance of the K-best detector, resulting it to be outperformed by the LMMSE detector. In the 8 × 8 case, the K-best LSD outperforms the LMMSE detector, since the channel conditions are more challenging for the LMMSE detector.