Abstract
Higher peak data rate and lower latency are targets included in Release 8 Long Term Evolution (LTE). This thesis is focused on downlink transmission scheme, in which the interface is BIC-OFDM and SISO based. The HARQ scheme implemented is multiple parallel stop-and-wait and is built around a CRC code for error detection and Turbo Codes for error correction. AMC algorithms are investigated to allow the transmitter to vary its mode, compounded by the set modulation and code rate in order to maximize the goodput, which represents the average number of bits belonging to error-free data received by unit of time. These algorithms are based on some feedback information, addressed as Link Quality Metric (LQM). The particular LQM exploited within this work, the κESM , based on the effective SNR Mapping (ESM) techniques, has been proved to be a reliable data link level performance predictor allowing a PER estimation, employing a variety of modulation schemes. Although the κESM method is reliable, when Turbo Codes are used, it need of an accuracy calibration, fundamental for a correct estimation of the effective SNR. In this work an efficient system is conceived when a HARQ type III scheme is considered, in manner to adapt the LQM estimation to the mapping block used by the AMC algorithm.
