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

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XPP – An Enabling Technology for SDR Handsets

Eberhard Schüler and Lorna Tan

PACT XPP Technologies

4.1. Introduction

4.1.1. The Challenge

Next-generation mobile terminals must provide consumers with a wide host of applications and connectivity to meet the demands of an ever-advancing concept of mobile connectivity. Users increasingly will expect their mobile terminals to connect to any possible network infrastructure anywhere in the world. In addition, the number of transmission standards increases continuously. Therefore, the mobile terminal must be able to adapt dynamically to any wireless infrastructure and to download and run applications offered by the service providers.

Wireless protocols for GPRS, CDMA, UMTS and wireless LANs require processing power that exceeds the capabilities of the conventional microcontrollers and DSPs dominating current generations of wireless terminals. Figure 4.1 gives an indicative comparison of the processing needs of several standards. GSM phones require approximately 10 MIPS. GPRS/HSCSD functionality requires approximately 100 MIPS. For the implementation of EDGE around 1000 MIPS are required. Potentially up to 10000 MIPS are required for the implementation of third generation UMTS/W-CDMA. Wireless LAN protocols implementing orthogonal frequency division multiplexing (OFDM) require around 5000 MIPS.

4.1.2. The Dilemma

For maximum flexibility, all functions of a mobile terminal should be defined in software. However, because of the computing ...