A tight lower bound for the bit error ratio of space-time block codes

In this contribution, a tight lower bound for the bit error ratio (BER) of space-time block codes (STBCs) over uncorrelated wireless multiple-input multiple-output channels using a maximum likelihood receiver is presented. We show that the performance of an STBC essentially depends on a few so-called error types (ETs), each ET being associated with a specific Euclidean distance governing the error probability. In our performance evaluation, only the smallest distance out of these distinct distances (one for each ET), is considered, thus leading to a minimum distance lower bound (MDLB). The resulting MDLB is compared to the union bound and to the simulated BER performance, showing a tight approximation for all STBCs considered.