Adaptive modulation and power allocation for OSTBC

Adaptive modulation and power allocation schemes have been widely used in multiple-input multiple-output (MIMO) systems to enhance spectral efficiency while maintaining bit error ratio (BER) to a target level. We derive the spectral efficiency of orthogonal space-time block codes (OSTBC) that can be achieved by applying adaptive modulation and power allocation. Compared to non-adaptive power scheme, the adaptive power allocation can achieve substantial gain in the spectral efficiency. Moreover, channel estimation errors are taken into account and the impact on the spectral efficiency is investigated.