Cross-layer link adaptation for IEEE 802.11n

This paper considers the use of cross-layer MIMO fast link adaption (FLA) algorithms in the context of IEEE 802.11n. An FLA technique based on packet error rate (PER) that makes use of the exponential effective SNR mapping (EESM) is proposed. Additionally, a bit error rate (BER) based FLA scheme is proposed that simplifies the calibration procedure without any significant performance degradation. Results show that both, PER- and BER-based, FLA techniques select the modulation and coding scheme (MCS) in a close to optimum fashion in the sense of maximising the data throughput while satisfying a prescribed packet error rate (PER) target. Channel estimation errors have also been considered, revealing the importance of good channel estimators in order for FLA strategies to work satisfactorily.