Research On Implement And Performance Of Higher Order Modulation In LTE-Hi

Data services of 3 GPP Long Term Evolution system mostly happen in the indoor hotspot Scenario.In order to response the huge demand for data services in hotspot area and based on the existing LTE technology and industry,we need to optimize LTE-A technology in indoor hotspot scenarios where data services mostly happen.Currently 4G LTE network has been commercial,the wireless data services will be inevitably carried by the LTE network in future.On the basis of the existing LTE networks and technologies,it is urgent to search and standardize the enhancement technologies in hotspot scenarios.The paper mainly research high-order modulation of LTE-Hi Hotspot enhancement technologies.The main contents of the research are concluded as follows:In order to achieve the function of 256QAM modulation and demodulation,we need to design 256QAM modulation and demodulation module and adapt rate matching module,AMC module in the LTE-A link-level simulation platform.Error Vector Magnitude as a performance indicator for transmitter distortion,quantified by main RF path loss factors such as non-linear distortion,phase noise and IQ imbalance.The EVM is modeled as a zero-mean complex Gaussian random variable with variance of ?2 which is added to the transmitted symbol.We obtained EVM tolerance rate is 4 percent by throughput and SNR curve.In order to bring 256QAM modulation technology into LTE-A system-level simulation platform which has an indoor hotspot scenario,we refer to 3GPP proposal on 256QAM design principles and redesign CQI/MCS/TBS configuration.We observe the effects of user throughput,spectrum efficiency by Comparing to Small Cell Scenario 3 between sparse scenario and dense scenario as well as modulation between 256QAM and 64QAM.Simulation results show that 256QAM modulation used in indoor hotspot scenarios can bring performance significantly especially in the Small Cell Scenario 3 sparse scenario.