DiffServ Model with Backpressure for CDMA2000

The nodes with shared-queues at the CDMA2000 data network have inherent rate mismatch and a single level of service. A core node, the packet control function (PCF) is processing power limited. Whereas a feeding node, the packet data serving node (PDSN), has superior processing metrics. A close-loop backpressure solution was proposed at the literature to efficiently control the PCF queue by utilizing PDSN free buffer space during PCF congestion events. Differentiated services (DiffServ) have been designed for Internet to provide multiple levels of network services. We propose a model for providing service differentiation at the CDMA2000 data networks. The model aims to provide service differentiations comparable to the traditional DiffServ model. The proposed improvement is in providing those services under the CDMA2000 structure of tandem nodes with large rate mismatch and a constraint of maintaining the complexity level of the processing limited core node (the PCF). The model uses a combination of backpressure and DiffServ techniques. The backpressure mechanism is used to push congestion from the PCF to the PDSN edge node where superior treatment of differentiated services can be provided to the traffic. The model differentiates services in terms of the relative access to the output link bandwidth and provides distinct handling to traffic at the multiple RED physical queues. It enables differentiation in terms of the achieved relative throughput, packet loss rate, delay, and jitter. We demonstrate the solution´s robustness with various traffic scenarios and system topologies. We show that our architecture is effective in providing bandwidth differentiation, as well as throughput, packet drop rate, and average delay preferences.