Dynamic Outer Loop Link Adaptation for the 5G Centimeter-Wave Concept

A 5th generation (5G) of wireless communication systems is expected to be introduced around 2020 to cope with a rapid increase of mobile data traffic. One of the main challenges of our envisioned 5G centimeter-wave concept is a large signal to interference plus noise ratio (SINR) variability, due to a flexible uplink/downlink (UL/DL) scheduler that aims at dynamically accommodating the traffic while reducing the latency. The use of advanced receivers and recovery mechanisms has been proved not to be sufficient to deal with such variability. In this paper, the potential of outer loop link adaptation (OLLA) to cope with the aforementioned problem is studied, and a dynamic OLLA (d-OLLA) algorithm is proposed. System level simulations show that d-OLLA provides an average throughput gain of up to 23% and 16.6% when using fixed rank 1 and rank 2, respectively, and 20.7% gain with rank adaptation, without adding extra complexity in the system.