Massive MIMO-OFDM System using Fractional Fourier Transform under Two-Wave with Diffused Power Fading

Abstract

Massive MIMO-OFDM system is an effective way to boost the spectral efficiency and data throughput of wireless communication networks. It is very simple to examine a user's performance when it is assumed that they are stationary; but, if the user is moving at a specific speed, it can be challenging to keep base station and the user in constant communication. Inter-carrier interference (ICI) is a problem that the conventional system cannot handle in a time-varying, non-stationary, rapidly fading, and highly mobile environment. FrFT-OFDM, a multicarrier modulation technique, is the technology that reduces the ICI problem in OFDM systems. For this reason, it is urged to combine Massive MIMO and FrFT-OFDM systems. FrFT is used to improve the bit-error-rate and raise the correlation coefficient in order to lessen the impact of ICI. FrFT is used in place of FFT because of its unexpected features. This thesis derives new formulas for the correlation coefficient, the closed form bit-error expression that depends on the correlation coefficient, and the average power of the ICI for a massive MIMO FrFT-OFDM system, assuming a fast-fading channel. Wireless communications systems benefit greatly from Massive-MIMO-FrFT-OFDM systems. Since the primary challenge with Massive MIMO-OFDM systems is channel aging. The effect of channel aging on the Massive MIMO FrFT-OFDM system is also examined in this thesis. The excellent performance of the Massive MIMO-FrFT-OFDM system in mitigating the effects of channel aging has been seen, due to its strong correlation in the Doppler-shifted environment. The primary focus of this research is how a two-wave-diffused-power (TWDP) fading model affects the Massive MIMO-FrFT-OFDM system as a result of channel aging. By considering the aged TWDP fading channel, this thesis also develops a unique closed-form formulation of BER and the achievable rate for the stated system. Spatial diversity and spatial multiplexing are the two methods used by MIMO systems to transmit data. Many copies of the same data delivered by many antennas in different formats are known as spatial diversity. When using spatial multiplexing, information from several antennas is combined throughout various time periods before being multiplexed by a transmitter. It is well known that the most promising MIMO-FrFT-OFDM systems increase a system's capacity and data throughput in a frequency selective fading channel. The system has to be encoded in orderto improve system reliability. Block coding and parity coding are the two types of encoding methods available. The STBC, SFBC and OSTBC techniques are the three main block encoding methods. A low-density parity-check (LDPC) code, a well-known parity coding method, is also covered. In this research, the SFBC approach is the main focus. Under TWDP fading channel, SFBC coded MIMO-FrFT-OFDM system is taken into consideration. The BER equations for the M-QAM and M-PSK modulation schemes have been created in order to examine the system's performance. The LDPC coding technique is preferred by the 5G communication system because it offers faster encoding and decoding times and a reduced bit error rate (BER). For coded massive MIMO-FrFT-OFDM systems, unique closed-form equations of pairwise error probability are also obtained for various wireless fading channels such as Rayleigh faded, Rician faded, and TWDP fading channels. This thesis also investigates the Massive MIMO FrFT-OFDM system's performance using the Long Range (LoRa) modulation technique. The QAM modulation technology is used in the conventional method. QAM signals require high-power amplifiers to be sent, but LoRa modulated transmissions do not require additional power. LoRa modulation technique produces low-power, long-range communications. The TWDP fading channel is used to assess the system's performance. A separate closed form of the system's BER expression is also shown. The technology is used in an Internet of Things (IoT) application, a smart hospital. Heart attacks are a common condition that need for ongoing monitoring. In this thesis, a LoRa-based system is used to relay ECG data in a smart hospital. The data of a patient undergoing observation in a room equipped with an ECG is continually communicated to the nursing station, the doctor's workstation, and travelling physicians in hospitals. This technology transmits data at a high data rate, has a long battery life, a low error rate, and can transfer data over a large distance.