Research and Implementation of Downlink Simulation Platform Based on the LTE Protocol
|School||Nanjing University of Posts and Telecommunications|
|Course||Signal and Information Processing|
|Keywords||LTE Physical layer Downlink Multiple Input Multiple Output Simulation Platform Channel estimation|
With the vigorous development of mobile communications , showing the trend of mobile , broadband and IP-based global wireless communications . In order to counter the challenges of WiMAX, Wi-Fi , mobile broadband wireless access technology market , and improve the competitiveness of 3G in emerging broadband wireless access market , 3GPP began a study of the long-term evolution of UMTS technology (Long Term Evolution, LTE) technology , to achieve 3G technology to B3G and 4G smooth transition . R8 LTE physical layer communication protocol based on the LTE downlink physical layer link level simulation platform based on MATLAB modeling , design , and performance evaluation and validation of the platform of the key technologies . The paper first introduces the technical background , the evolution of the LTE system objectives and system architecture ; elaborated the key technologies of the LTE downlink physical layer OFDMA , MIMO , HARQ principle; focus on three of the MIMO implementations : transmit diversity , spatial multiplexing , beam forming were analyzed. Secondly, analysis of the basic principle of the downlink based on the LTE communication protocols , studied and realized LTE physical layer downlink level simulation platform ; gives a system configuration diagram of the downlink simulation platform , the realization of the principle of the main module and design flowchart ; key technology MIMO LTE physical layer in the simulation platform simulation assessments and algorithm analysis ; combination of MIMO and OFDM technology is verified by simulation can greatly improve the communication capabilities of the wireless communication system in a frequency-selective channel . Finally , based on this platform , research -based pilot LTE Downlink channel estimation algorithm , a detailed analysis of the LS , MMSE pilot channel estimation algorithm and various interpolation algorithm . MMSE channel estimation autocorrelation matrix inverse operation characteristics of large , proposed an improved method based on LMMSE algorithms - approximately linear minimum mean square error ( Approximate the the Linear MMSE , ALMMSE ) , and combined with Matlab simulation its performance and practicality verification and analysis . The simulation results show that the simplified algorithm similar MMSE algorithm performance and reduce the computational complexity , is easy to implement .