New LTE downlink CQI correction algorithm

In order to adapt channel variation and maximize throughput performance, Adapt Modulation and Coding (AMC) is used in Long-Term Evaluation (LTE) downlink. However, due to the wireless channel random variation, inaccurate reported Channel Quality Indicator (CQI) is introduced, which will affect quality of data transmission. Therefore, it is necessary to modify reported CQI in AMC process. Although this paper adopts a traditional CQI correction algorithm, it ignores the influence of great deviation and burst noise. To overcome these shortages, an improved CQI correction algorithm which is based on the traditional method is proposed. The new algorithm is not only depend on acknowledge of data blocks but also depend on previous modified CQI to correct current reported CQI. The performance of two CQI correction algorithm based on both perfect noise power estimation and real noise power estimation are simulated in a LTE downlink platform. By comparing these results, it can be conclude that performance of new CQI correction algorithm is better when the terminal moving in the high-speed channel model ETU300.