Abstract: A novel dynamic distributed admission control with adaptive reservation of bandwidth and multiple QoS sup- port of EDCA(enhanced distributed channel access) in IEEE802. lle based on cross-layer was presented. In this mecha- nism,the bits of the subcarrier of OFDM in the station are allocated to obtain the maximum channel capacity subjected to the maximum power at first and the bit rate is transmitted to the medium access control layer at the same time. By means of that, a dynamic reservation of the bandwidth was presented based on the distributed measurement, which a- dapts to the characteristics of the channel and the service. And an estimation of the surplus factor by center control half- based on model was presented, which overcomes the un-accuracy resulted by directed measuring and locality resulted by distributed estimation. The relationship between the service's parameters and the collision probability was obtained and the double admission criteria of the bandwidth and the collision probability was suggested to support the multiple QoS such as bandwidth and delay as well as error ratio of the frame. All above suggestions structure an adaptive admission control from the upper layer to the lower layer. The simulation shows the admission control presented outperforms the former in the utilization of the resource and the quality of the service.

Key words: Distributed admission control, Bits allocation of OFDM subcarrier, Dynamic reservation of the bandwidth,Computation of the collision probability and surplus factor, Multiple QoS support