System Simulation of HARQ in HSDPA with Performance Analysis

The system simulates the Hybrid Automatic Repeat Request (HARQ) mechanism in High-Speed Downlink Packet Access (HSDPA), providing comprehensive analysis and description of throughput performance and retransmission statistics. During simulation execution, we observed notable phenomena: under high-load conditions, system throughput significantly degrades while retransmission counts proportionally increase. The implementation employs stop-and-wait HARQ protocols with soft-combining techniques, where corrupted packets are stored in buffer memory for combination with retransmitted versions using Chase Combining or Incremental Redundancy algorithms. Additionally, we identified optimization approaches for HARQ performance enhancement, including implementing retransmission上限count limits through timeout counters and optimizing scheduling algorithms via proportional-fair or round-robin schedulers in MATLAB/Simulink environments. Through HARQ system simulation and analysis, we gain deeper insights into HSDPA performance characteristics, providing valuable references for system optimization through parameter tuning and algorithm improvements in physical layer communication protocols.