A Joint Design Of QoS Provisioning And Congestion Control For Multi-hop Wireless Networks

The capability of multi-hop wireless networks to provision QoS is of particularimportance when the real-time applications boost in current days. The scheduling and deliveryof data packets in a deficient method may probably cause network congestion, which will inturn decrease the capability of QoS provisioning in the network. By now QoS provisioningand congestion control are studied separately. To this end, we propose a joint design of QoSprovisioning and congestion control for multi-hop wireless network in this dissertation basedon our previous works of Differentiated Queueing Service (DQS) and Semi-TCP, whichprovide per-packet granular QoS and carry out efficient hop-by-hop congestion controlrespectively.While DQS and Semi-TCP are studied separately, we investigate the arising issues in thejoint scheme and propose possible solutions accordingly, including a fast estimation of thelatest departure time to decrease network contention, a method of checking overdue packets atthe exit of the queue to improve the bandwidth utilization，an adaptive delayed ACK schemeto further decrease inter-flow contention as well as an adaptive adjusted backoff Semi-TCPMAC based on DQS decisions to better carry out the DQS decision. This thesis implementsabove schemes in the same protocol stack on NS2simulation platform. Simulation resultsshow that our proposal improves the network performance in terms of goodput andend-to-end delay significantly, particularly in the scenario of mobile users.