BER Performance Analysis of FMT System with 4QAM Modulation

This paper presents a comprehensive Bit Error Rate (BER) performance analysis of Filtered Multitone (FMT) systems employing 4QAM modulation. The analysis includes MATLAB implementations of key components such as prototype filters and polyphase filter banks, which are crucial for achieving optimal spectral efficiency and interference reduction. The prototype filter design typically utilizes windowing methods (e.g., Hanning, Kaiser) or filter design algorithms (fir1, fdesign) to minimize inter-carrier interference, while the polyphase implementation efficiently decomposes the prototype filter into parallel branches for reduced computational complexity through decimation and interpolation techniques. Beyond evaluating fundamental performance metrics, this study further investigates the impact of channel impairments including multipath fading (modeled using Rayleigh or Rician distributions) and additive white Gaussian noise (AWGN) on system performance. Additional research avenues include comparative BER analysis under different modulation schemes (such as 16QAM, QPSK) and performance benchmarking between various prototype filter designs (Root-Raised Cosine, Gaussian) and polyphase filter configurations. The MATLAB code implementation encompasses: 1. Prototype filter generation using frequency-domain specifications with optimal roll-off factors 2. Polyphase decomposition algorithm for efficient filter bank realization 3. 4QAM modulator/demodulator with Gray coding implementation 4. BER calculation methodology incorporating Monte Carlo simulations 5. Channel modeling functions for fading and noise effects Through these analytical approaches and code implementations, engineers can gain deeper insights into system optimization strategies for 4QAM-based FMT systems, particularly in balancing spectral efficiency, computational complexity, and error resilience.