Performance analysis of transmission modes in 4G LTE/LTE-A downlink systems

The 3GPP LTE/LTE-A is the most promising technology for next-generation wireless communications providing peak data rates of 1 Gbps. The transmission mode has to be selected properly to improve the overall performance of user communication. The performances of the different transmission modes like single antenna port, transmit diversity, open loop spatial multiplexing are analyzed under normal conditions and open loop spatial multiplexing is having a higher throughput compared to the other two transmission modes. The window size used for channel estimation is an important factor affecting the throughput performance of the system. Based on the window size, averaging can be classified as time averaging, frequency averaging or both. The throughput performance of each transmission mode for different window sizes are obtained and analyzed. There is an improvement in throughput of 35 % for single antenna port mode with time averaging, an improvement of 4.5 % for both transmit diversity mode and open loop spatial multiplexing modes on using time/frequency averaging scheme. The simulation scenario uses LTE system toolbox for the design and verification which makes the formulation of the system model and the estimation of the channel parameters less complicated.