The Impact of RF-Impairments and Automatic Gain Control on UMTS-HSDPA-Throughput Performance

This paper presents radio frequency (RF)-receiver investigations related to UMTS-HSDPA throughput performance (TP). The investigated concept is based on a direct conversion receiver (DCR) architecture enhanced with a digital-front-end (DFE). Due to the use of a DFE some analog requirements decrease on the expense of a tightened ADC specification and a more complex digital signal processing chain. To efficiently use the whole dynamic range of the ADC under all operating conditions requires a smart automatic gain control (AGC) strategy for the analog gain stages. The effects of different ADC levels on the TP performance are investigated in detail. Based on these results a smart leveling strategy is developed. TP results including the proposed AGC-method are presented for the ITU-channel models PA3, PB3, and VA120.