Abstract: To support the different needs of transmission Qualities of Service (QoS) in local multimedia networks,a multi-priority hybrid slot transmission method based on IEEE 802.11e Enhanced Distributed Channel Access (EDCA) protocol was proposed．A hybrid slot is defined which includes some slots and the number of slots in it is less than or equal to the kinds of access categories．The access categories are assigned to the different priority slots according to the transmission QoS requirements．The collision probabilities of access categories with different QoS requirements in the data link layer can be fixed easily．The collision probabilities between the stations are significantly reduced,and the network qualities of the access categories with high transmission QoS needs such as throughput,drop rates,media access delay are improved compared with the traditional EDCA protocol．The multi-priority hybrid slot transmission method reveals a good adaptability to the station changes in the networks．It shows a better performance especially when the stations increase.

Key words: Multi-priority,Hybrid slot,EDCA,Saturated,Unsaturated