In this paper, we are investigating a dynamic admission control (DAC) scheme that is designed for guaranteed wireless video transmission over the IEEE 802.11e wireless LAN (WLAN) environment. To guarantee differentiated QoS services for network-adaptive video streaming, the proposed DAC is designed to utilize the video codec's layering characteristic as well as differentiation-capability of IEEE 802.11e MAC (multiple access control). Especially in order to match the time-varying hostile wireless environment, limited wireless resources for transmission opportunities are required to be dynamically reserved, coordinated, and utilized. Proposed realization of DAC is composed with three sub modules: reservation-based call admission control (CAC), dynamic service resource allocation, and on-flow service differentiation modules. To evaluate the performance of proposed DAC, we apply it to the wireless streaming of ITU-T H.263+ streams over the IEEE 802.11e WLAN, network simulator (NS-2) based simulation results show that it achieves both acceptable receiver-side video quality and efficient resource utilization in face of network loads and channel variations.