Abstract: This paper proposed a queue length based per-hop AC self adaptation (QLACSA) mechanism for Mobile Ad Hoc networks (MANET).The objective of QLACSA is to balance the end-to-end delay for packets with different routing path,thus to guarantee the end-to-end delay for delay sensitive services.QLACSA serves in the MAC layer.For the flows with delay requirement,QLACSA divides the flows’ total delay requirement into each-hop expected delay requirement,and dynamically adjusts the AC priority for each packet hop-by-hop according to the packet’s delay situation,local delay requirements,and each AC queue’s state,such that the packets can reach their destination within the required end-to-end delay specified by the QoS requirement.QLACAS utilizes the policy of “survival of the fittest” through a traffic shaping strategy.It drops the packets which can probably not reach the destination before the deadline in time,thus to release all the associated resources for other packets.Simulation results show that QLACSA is able to guarantee end-to-end delay for the delay sensitive services.The throughput of the flows with long hop increases by 211%~245%.

Key words: Ad Hoc,Multi-hop,802.11e,EDCA,AC