Link-Level Simulation of WiMAX Fixed Version

Link-level simulation for the fixed version of WiMAX is a critical method for evaluating its physical layer performance. Using the MATLAB platform enables detailed reproduction of key processes such as modulation, coding, and channel transmission. The simulation must incorporate the following core modules:

Signal Generation and Modulation: Generate signals based on OFDMA technology, with implementation of modulation schemes like QPSK and 16QAM for mapping and demodulation. MATLAB code typically involves using built-in functions like pskmod and qammod for constellation mapping, along with OFDM modulation through ifft operations. Channel Coding and Decoding: Implement forward error correction coding (e.g., convolutional codes, Turbo codes) and interleaving processing to simulate anti-interference capability in practical transmission. This can be achieved using functions like convenc and vitdec for convolutional coding/decoding, and matrix reshaping for interleaver implementation. Channel Modeling: Employ multipath fading models (such as ITU-R M.1225) and additive white Gaussian noise (AWGN) to simulate real channel conditions. The communication toolbox provides functions like rayleighchan for fading channel simulation and awgn for noise addition. Synchronization and Equalization: Address symbol timing offset and carrier frequency offset issues, compensating for channel distortion through equalization algorithms like MMSE. Implementation typically involves correlation-based synchronization and using mmseequalizer function for channel compensation. Performance Analysis: Calculate bit error rate (BER), frame error rate (FER), and throughput metrics, comparing theoretical values with simulation results. MATLAB's error rate calculation functions like biterr and system object analyzers facilitate comprehensive performance evaluation.

The simulation must align with parameter configurations from WiMAX fixed version standards (e.g., IEEE 802.16d) to ensure practical reference value. MATLAB's flexibility supports modular development, facilitating easy extension to advanced features like MIMO through phased array system toolbox integration.