Ontwikkeling van een embedded mobiele terminal (TES.5177)

The research is directed at the design and realization of an embedded mobile terminal for speech and data. In the traditional way of designing, mobile terminals such as DECT and GSM telephones are designed and realized with focus on low-cost hardware. Adjustment to the wishes of users or to specific circumstances is then hardly possible. An embedded approach, however, in which a large part of the functionality is realized in software, can provide the desired flexibility and, within boundaries, the capability to expand. This flexibility can then, for example, be used to make high-speed data transmission via a mobile channel adaptive. This is important for future broadband radio communication.

The functions that the mobile terminal must perform can be divided into the functions that are typically not time-critical such as call set-up, channel selection, handover to another base station, etc. and the time-critical operations on the speech signal: the compression, channel coding, modulation (and vice versa) and further radio processing. The non-critical, or better, the less time-critical functions can be effectively carried out with a micro-controller. The situation is different for the time-critical signal processing where a powerful processor is required. Since energy usage is a heavy design constraint with mobile terminals, standard processors cannot be applied here. Such functions are presently therefore generally executed in hardware. This impacts the flexibility of the terminal negatively, however. The design thus requires a careful evaluation regarding the realization in software and/or hardware.

This project focuses on the implementation of algorithms in the physical layer of the OSI model (the so-called radio algorithms), such as multi-user detection and adaptive modulation techniques, on a software radio architecture. Software radio is an upcoming technology and is considered to enable the development of flexible radio systems that have the following features: multi-service, multi-standard, multi-band, reconfigurable and reprogrammable. Using a software radio, the mobile terminal can provide flexibility with reasonable energy usage. The radio algorithms and functionality described in a higher description language such as Cossap are converted into a netlist for programmable components. This can involve an architecture consisting of a programmable RF front-end, an A/D converter and ASICs, reprogrammable FPGAs and programmable DSPs.

The purpose of the project is, on the one hand, the development of a design methodology that converts the desired specific radio functionality optimally (considering energy usage, cost, performance, etc.) into a software radio realization. The methodology must be flexible enough so that the optimal solution can follow the trends in the component market. On the other hand, the project is intended to yield a demonstration system that can provide the selected (sub-)functionality.

For results, see http://www.sas.el.utwente.nl/home/SDR/

Eight companies are involved in this project.