Estimating the Computational Requirements of a Software GSM Base

In this paper, we describe the software implementation of a GSM base station and consider the performance of each of its Radio Interface components. The performance of each software module is evaluated using both a % CPU metric and a processor-independent metric based on SPEC benchmarks. These results can be used to dimension systems, e.g., to estimate the number of GSM channels that can be supported by a given processor connguration, and to predict the impact of future processor enhancements on base station capacity. 1 Introduction Historically, the use of software within radio systems has been restricted to low bandwidth out-of-band tasks, such as signaling, operations and management. Implementation of the in-band Radio Interface functionality has leveraged analog front ends, that partition the band into individual FDM channels, and digital components that perform the time division and speech processing functions. The design of the digital portion is typically based on some compromise between a full ASIC implementation and pro-grammable DSPs. In particular,past eeorts to develop software radios have leveraged DSP-based software to emulate functions traditionally implemented in dedicated digital hardware 5, 7]. In contrast, our virtual radio approach involves the reexami-nation of the overall system from a software designer's perspective , with speciic emphasis on the virtualization of RF sources. Advances in processor