Reconfiguration Level Analysis of FFT / FIR Units in Wireless Telecommunication Systems

Wireless communications domain have been evolving in a fast way in the past years in order to support new services for users. This evolution led to the apparition of a variety of standards like UMTS (3G), IEEE 802.11g (WLAN) and DVB-H. Extracting similarities between multiple radio access techniques is a must to define a low cost system enabling the joint support of multiple telecommunications standards. This paper evaluates different approaches to take benefit from the functional or computational analogy between standards, it also discusses the trade-off to be defined by the designer when studying multi-standard devices. Two main functions in wireless communications are Finite Impulse Response (FIR) Filters and Fast Fourier Transforms (FFT). Thus, in this paper, we are focusing on these two functions to present different reconfiguration levels to be considered when designing a unit supporting these functionalities. Implementation details of the different reconfigurable units are exposed. A qualitative and a quantitative comparison between the different reconfiguration levels is also conducted.