Abstract— In this paper, we propose and evaluate the performance of new link layer frame transmission techniques for MIMO (multiple input multiple output) wireless systems from a link layer perspective using frame error rate (FER), frame loss rate (FLR) and link layer throughput metrics. We first introduce a novel link layer transmission scheme for wireless networks when channel state information (CSI) is available at the transmitter (CSIT). This new scheme is based on an adaptive algorithm diagonal precoder which selects the proper orthogonal sub-channels of the MIMO link to use in order to increase the link layer throughput while maintaining an acceptable frame loss rate. Computer simulations show that the proposed MIMO-aware link layer algorithm provides a significant performance improvement. Second, we propose and evaluate the performance of different ARQ (automatic repeat request) retransmission strategies. Our performance evaluation shows that by decreasing the multiplexing g...