Development of MIMO diversity technique with discrete wavelet transform for millimeter wave communication system

Abstract

Millimeter wave (mm wave) wireless communication systems are considered as the key feature technology for future next generation i.e. 5th generation (5G) as mm wave band has prospective to meet high data rate, mobility and less energy consumption. Spectral efficiency improvement is one of the primary requirements for future wireless communication networks. One of the major research problems is that the signal loss at the receiver because of channel propagation. The received signal becomes more sensitive when the system uses mm wave since its frequency is very high between 3 GHz to 300 GHz. To enhance the performance of wireless communication system, exploitation of Multiple Input and Multiple Output (MIMO) antenna diversity has become well known technology. Orthogonal frequency division Multiplexing (OFDM) systems are used to improve the spectral efficiency with the use of wavelet transforms. The Discrete Wavelet Transform (DWT) has superior properties compare to Fast Fourier Transform (FFT) as it eliminates the use of cyclic prefix which improves spectral efficiency. The wavelets transforms are also beneficial in many aspects such as channel modeling, data compression and interference mitigation. Hence, a MIMO antenna diversity technique is developed with wavelets transform to improve the performance and spectral efficiency of the system. The multiple antenna arrays such a Uniform Linear Array (ULA) with half-length spacing has been considered. The system is deployed at 60 GHz as it is unlicensed spectrum band and suitable for short distance propagation for both line of sight and multipath propagation channel. The QAM modulation and demodulation are performed at the transmitter and receiver. The data is converted into DWT coefficients by reshaping property. The wavelets are then constructed and reconstructed by perfect reconstruction property. Therefore, the inverse DWT at the transmitter and DWT at the receiver could improve the Bit Error Rate (BER) performance. The performance in terms of BER are carried out in MATLAB simulation software for all diversity scenarios Single Input and Single Output (SISO) DWT, Multiple Input and Single Output (MISO) DWT and MIMO DWT. Among all of them MIMO DWT is better. The performance of MIMO OFDM with different wavelets is also simulated and Haar wavelets transform performance is better when compared with another wavelet transform by 2 dB at 10-3. The MIMO DWT BER results shows better improvement when compared with the benchmarking by 2 dB at 10-3. The analytical results when compared with simulation results are good in agreement with minimum discrepancy.