Link Adaptation for MIMO-OFDM Systems

摘要: The paradigm of the design a wireless system has changed. Since use dimensioning for “worst case”, which means to work on fading margin available when channel its poorest behavior, driver optimization evolved more suitable resources performing reliable communication. This approach is then called link adaptation (LA), chooses parameters are most usage in certain condition. always increasing demand higher data rates, lower energy consumption, etc., requires that utilized as efficiently possible and LA techniques already reality any modern communication systems achieve goal. While many aspects LA, such different modulations code rates providing better “protection” streams according condition, have been understood, each set “interesting parameters” be adapted multiple dimensions trade-off between gains signaling overhead still provides challenges answered. Typical used procedure modulation coding. choice allows improve/decrease spectral efficiency rate impacts amount redundancy inserted error protection into frames. However, it envisage exploitation other features system, instance spatial frequency domains. chapter describes transmission modes considering important performance particular extension MIMO-OFDM case fourth generation (4G) systems. rest organized follows. fundamentals multipleinput multiple-output (MIMO) presented Section 10.2, where classical MIMO schemes described. 10.3 discusses diversity multiplexing can extracted from