Downlink throughput analysis in a WCDMA network with mixed QoS traffic classes

In UMTS, four traffic classes have been identified: conversational, streaming, interactive, and background, to fulfill the QoS requests from the application or the user. To effectively manage the radio resources, shared between these different QoS classes has become an important network planning issue. In this paper, the maximum available resource, R_max, of a cell (per sector per carrier) is defined in terms of the maximum downlink transmission power, the average propagation loss, the orthogonality factor, and the other-to-own-cell interference ratio. The resource sharing factor of each traffic class can be calculated by dividing the total resource allocated for that class by the maximum available resource, R_max. The summation of the resource sharing factors of all traffic classes is smaller than one. This paper also shows that the average throughput of the downlink is a weighted sum of the resource sharing factors. Downlink throughput calculations for various traffic conditions with mixed QoS classes are presented by using the derived weighted sum equation.