Transmission Opportunity (TXOP) which is specified in the IEEE 802.11e enables a Wi-Fi station to transmit multiple frames consecutively. In this paper, we propose an adaptive transmission scheme based on the Dynamic Aggregation and Fragmentation (DAF) algorithm. With real-time scheduling and adaptive TXOP allocation being the main focus of the suggested adaptive transmission scheme, optimum transmission parameters are also calculated and used under different Bit Error Rate (BER) conditions. The suggested transmission scheme works in synchronous with the DAF scheme which focuses mainly on efficient use of TXOP and minimizing retransmissions by adjusting the frame and fragment size dynamically. Analytical model for the scheme is developed to evaluate the throughput, delay performance, and stability with respect to different traffic classes and scenarios, and proved with NS-3 simulator. The simulation result shows that there is significant throughput improvement keeping the delay minimum with the scheme while ensuring long term fairness and performance stability to channel conditions and underlying physical rates.