Performance analysis of interference averaging for link adaptation in LTE/LTE-A downlink

In LTE/LTE-A system, Link Adaptation (LA) is a crucial procedure. One key factor is to have precious interference estimation considered in the LA, since the accuracy of interference estimation has a significant impact on the Channel Quality Indicator (CQI). In this paper we pay our attention to the CQI mismatch problem in Link Adaptation procedure, which is mainly caused by rapid fluctuation of inter-cell interference depending heavily on traffic load. Obvious performance loss has been observed in system level simulation due to this problem, thus we propose an interference averaging scheme for CQI calculation by considering not only the instantaneous interference level, but also the interference level in the past when UEs doing CQI calculation. Based on intensive system level simulations, it can be observed that the proposed scheme can improve the system performance both for average throughput and cell-edge throughput.