Performance Comparison of LTE-A Enhancement Techniques

Frequency selective scheduling is an attractive feature in the 3GPP LTE-A system that allows optimum usage of the allocated spectrum frequency scheduling. Frequency scheduling relies on Channel Quality Indicator (CQI) report by the user equipment (UE). The main challenge in
CQI reporting consists of reduction in number of CQI feedback overhead maintaining the performance of the system throughput. Several CQI feedback scheme have been proposed for 3GPP LTE-A systems. The work in this thesis evaluates the performance of LTE-A downlink with MIMO techniques and the threshold feedback compression scheme. MIMO technology involves the use of multiple antennas at the transmitter, receiver or both. There are different combinations of array configuration and detection schemes that can be implemented to achieve high data rate with low bit error rate. These detection schemes are Zero Forcing (ZF), Minimum Mean Square Error (MMSE) and Soft Sphere Decoding (SSD). The performance metrics considered are throughput and BER. These are used to evaluate the performance of LTE-A in AWGN channel and Rayleigh Fading channel with detection schemes for Single Input Single Output (SISO) and spatial multiplexing. The simulations results show that the performance of MIMO is better than SISO in Rayleigh Fading channel model when SSD is employed. When threshold feedback compression scheme is utilized, performance in the flat-fading channel model is greater than the performance of unusing threshold feedback compression scheme by 2 Mbps at SNR = 20 dB. LTE-A Downlink is modeled and simulated using MATLAB simulation R2013a and Vienna LTE Simulator.