Software Defined Radio: Baseband Technologies for 3G Handsets and Basestations

11

Reconfigurable Parallel DSP – rDSP

Behzad Mohebbi and Fadi J. Kurdahi

Morpho Technologies, Irvine, CA

11.1. Introduction

The majority of today's commercial digital signal processors (DSPs) can be placed into one of two main categories: programmable DSP or dedicated DSP. While programmable DSPs have the advantage of using the same computational kernels for all algorithms, dedicated DSPs are hardwired for specific algorithms, or classes of algorithms. Even though both have special instruction sets, dedicated DSPs are usually faster and consume less power than general-purpose programmable DSPs. The level and the extent of the architectural specialization of a dedicated DSP is defined by the application algorithms for which the processor is targeted, which consequently reduces the general applicability of the DSP.

By far the largest application area for DSPs, in recent years, has been in the support and implementation of digital communication baseband algorithms. There are overwhelming commercial reasons for the selection and the increased usage of DSPs in such systems. The third generation (3G) wireless communication systems are designed for increased spectral efficiency and high data rate transmission. These emerging systems are based on advanced forms of wideband multiple access techniques, such as CDMA, and broadband modulation techniques, such as spread spectrum and OFDM, which demand a much higher signal processing load than the previous second generation (2G) systems. This ...