A cutoff rate based cross-layer metric for MIMO-HARQ transmission

This paper addresses the evaluation of cross-layer metrics for wireless access systems employing hybrid automatic retransmission request (HARQ) processing combined with multiple input multiple output (MIMO) data transmission. The proposed metrics can be utilized by resource management algorithms to control resources in next generation networks. The objective is twofold. First, we evaluate a reliable throughput performance metric encompassing MIMO as well as HARQ protocol parameters in a single expression. In particular, we perform an information theoretic consideration by employing the conditional cutoff rate for MIMO transmission while the HARQ process is described by the renewal-theory. In a second step, we illustrate the flexibility of the metric evaluation approach by its application to two transmission schemes. Both schemes employ V-BLAST transmission but differ in HARQ processing. Results given for all schemes clearly indicate the suitability of the proposed metrics. With the metrics introduced we also get hints on designing wireless transmission schemes with multi antenna technologies and HARQ processing while avoiding intensive simulation studies