Abstract: The wireless access point(AP)is a key device in wireless LAN(local-area network),and its performance influences the data transmission quality strongly.To analyze the impacts of the main parameters in the IEEE 802.11 protocol on the wireless access system and design low-cost AP,an abstract model of wireless access system is built according to system design flow of complex embedded system before the hardware/software of AP is actually realized.Based on the simulation of the model,the influence of the parameter CW_min(minimum contention window)on the performance metrics such as valid throughput and average frame delay were analyzed.The appropriate processing speed of CPU is also confirmed by analyzing the CPU occupancy.The results show that the key design parameters can be determined through system-level modeling and performance evaluation in the earliest design phases.