Programmable Digital Signal Processors (DSPs) are pervasive in the second generation (2G) wireless handset market for digital cellular telephony. This did not come about because everyone agreed up front to use DSPs in handset architectures. Rather, it was a result of a battle between competing designs in the market place. Indeed, the full extent of the use of programmable DSPs today was probably not appreciated, even by those who were proposing DSP use, when the 2G market began to take off. In this chapter we present the argument from a pro-DSP perspective by looking at the history of DSP use. | The Application of Programmable DSPs in Mobile Communications Edited by Alan Gatherer and Edgar Ausländer Copyright 2002 John Wiley Sons Ltd ISBNs 0-471-48643-4 Hardback 0-470-84590-2 Electronic 2 The History of DSP Based Architectures in Second Generation Cellular Handsets Alan Gatherer Trudy Stetzler and Edgar Auslander Introduction Programmable Digital Signal Processors DSPs are pervasive in the second generation 2G wireless handset market for digital cellular telephony. This did not come about because everyone agreed up front to use DSPs in handset architectures. Rather it was a result of a battle between competing designs in the market place. Indeed the full extent of the use of programmable DSPs today was probably not appreciated even by those who were proposing DSP use when the 2G market began to take off. In this chapter we present the argument from a pro-DSP perspective by looking at the history of DSP use in digital telephony examining the DSP based solution options for today s standards and looking at future trends in low power DSPs. We show that some very compelling arguments in favor of the unsuitability of DSPs for 2G digital telephony turned out to be spectacularly wrong and that if history is to teach us anything it is that DSP use increases as a wireless communications standard matures. As power is the greatest potential roadblock to increased DSP use we summarize trends in power consumption and MIPS. Of course history is useless unless it tells us something about our future. Moreover as the DSP debate starts to rage for third generation 3G mobile communication devices we would like to postulate that the lessons of 2G will apply to this market also. A History of Cellular Standards and Wireless Handset Architectures 1G and 2G Standards The first commercial mobile telephone service in the US was established in 1946 in St. Louis Missouri. This pre-cellular system used a wide-area architecture with one transmitter covering 50 miles around
