This paper evaluates subjective QoE of audio and video transmission over Wireless LAN with a reliable groupcast mechanism and a rate-adaptation mechanism. As a reliable groupcast method, we employ LBP (Leader-Based Protocol) without RTS/CTS. For a rate-adaptation mechanism, we utilize ARF (Auto Rate Fallback). We compare the joint method to groupcast without retransmission and IEEE 802.11 GCR Unsolicited Retry with a fixed rate. Computer simulation with ns-3 is carried out. We then assess QoE through a subjective experiment. The result shows that the joint method enhances QoE under various conditions.