DiffServ-aware priority queuing improves IP QoS support on HSDPA

A priority queuing scheme for high-speed downlink packet access (HSDPA), that utilizes the QoS information from the IP layer of the differentiated services (DiffServ) architecture, is presented. The user packets are scheduled for transmission on a set of shared code channels depending on the radio channel condition and the drop precedence (packet colour) of the IP packets marked by the ingress DiffServ node. The out-of-profile packets that are beyond the contracted service level agreement are marked with high drop precedence and thus are given less priority (served only on residual resources, i.e., code and power). By truncating the throughput for the out-of-profile packets, the in-profile traffic experiences a higher throughput, consequently improving the QoS support. The throughput is evaluated using dynamic system level simulations, which incorporate the main features of HSDPA, i.e., adaptive modulation/coding scheme (AMCS) and hybrid-ARQ (HARQ) as well as code multiplexing of different users.