Toward the software realization of a GSM base station

Recent advances in processor and analog-to-digital conversion technology ha ve made the software approach an increasingly attractive alternative for im plementing radio-based systems, For mobile telephony base stations, the adv antages with the new architecture are obvious: great cost savings by using one transceiver per base transceiver station (BTS) instead of one per chann el, tremendous flexibility by moving system-specific parameters to the digi tal part, and allowing the support of a wide range of modulation and coding schemes. This paper considers the software implementation of a GSM BTS, and analyzes the performance of each of its radio interface modules. The performance of each software module is evaluated using both a % CPU metric and a processo r-independent metric based on SPEC benchmarks. The results can be used to d imension systems, e.g., to estimate the number of software-based GSM channe ls that can be supported by a given processor configuration, and to predict the impact of future processor enhancements on BTS capacity. Two novel asp ects of this work are the portability of the software modules and the platf orm-independent evaluation of their computational requirements.