Characterisation of wideband code division multiple access uplink transmit power for typical mobile usage patterns

Abstract

With the ever-increasing demand for higher data rates and longer talk times, designing low-power RF front ends in wideband code division multiple access (WCDMA) mobile handsets is an important task. However, the power efficiency of current WCDMA RF front ends, particularly power amplifiers, is very low over the range of typical output power levels. Thus, to improve the RF characteristics, it is important to understand typical output power requirements for WCDMA handsets in practical mobile usage conditions. In this study, the authors present a characterisation and analysis of WCDMA uplink power or handset transmit power for typical mobile usage patterns by location. Unlike previous studies, in this experimental study the authors take measurements using a real WCDMA phone over a commercial universal mobile telecommunications systems network while simulating practical mobile user behaviour. Specifically, the distribution and statistics of WCDMA uplink transmit power at various locations are investigated. Similar locations are then grouped to form four practical mobile usage scenarios, and their frequency histograms are analysed. Further, in each scenario the authors examine the dependency of uplink transmit power on several key factors (i.e. radio coverage, handset position and network loading) and the statistical properties of the transmit power variation.