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　CWmin　(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.