Symbol error rate performance of convolution coded 4X4 MIMO systems using LDC and precoding

Abstract

In today’s wireless world, the demand for high speed data is increasing at fast pace as the number of wireless based applications are increasing day by day. Next generation wireless communication systems have to achieve very high throughputs and improved reliability in order to fulfil the desire for faster and reliable communications. But present generation systems cannot achieve higher data rates because of scarcity in band limited spectrum for wireless communication. MIMO’s are the most promising techniques for providing outstanding reliability and exceptionally high data rates. LTE-A has introduced 4x4 MIMO in the uplink. LTE networks based on 4x4 MIMO system targets at the peak data rate of 500 Mbit/s for uplink. But design challenge puts hindrance to LTE’s movement to 4x4 MIMO. Next generation wireless systems has to develop efficient coding and signal processing techniques to easily switch to 4x4 MIMO systems with increased data rate and high spectral efficiency. Linear Dispersion Codes (LDC) outperforms many space time coding techniques and BLAST technique. LDC provides high data rate and good error performance for any arbitrary configuration of transmit and receive antennas. In this dissertation work LDC systems of 4x4 MIMO configurations has been used. LDC outperformed spatially multiplexed systems by 6dB at Symbol Error Rate (SER) of 10-2.9. However, the said system was suffering from burst errors. In order to combat burst errors, channel encoding has been used along with LDC systems. Further, in this dissertation work, precoding has been used in the convolution concatenated 4x4 MIMO systems using LDC. By precoding, Convolution coded system shows SER of 10-3 at 16dB while LDC system shows same SER at SNR of 24dB for Rayleigh channel. The proposed system has achieved SNR of 13dB at 10-2.9 SER, while traditional systems were achieving a maximum of 21dB of SNR at same SER for Rician channel. Henceforth, the proposed system achieved an improvement of 8dB as compared to conventional systems in both fading models.