A wireless device includes a data structure that relates peak channel capacity to the quality of the wireless communication link. The wireless communication link quality forms an index to indicate the expected peak channel capacity for that particular quality value of the wireless communication link. The wireless device uses the data storage structure to determine an expected data transfer throughput based on the quality of the wireless communication link. A transfer rate lower than expected may indicate congestion in the core network or the RAN. In this case, the network may slow the data delivery from the data source or temporarily suspend delivery. Conversely, low data throughput may be the result of a poor quality wireless communication link. If the data structure indicates that the data throughput corresponds to the expected throughput for the quality value of the wireless communication link, the system need not take any steps to reduce congestion.