Software Defined Radio: Enabling Technologies

8

Parametrization – a Technique for SDR Implementation

Friedrich Jondral

University of Karlsruhe

Mobile communications is mainly a service driven business. But there are important marginal conditions from physics and technology that may not be ignored when developing a mobile communications system; the frequency spectrum is a scarce resource. Therefore terminals, mobile as well as base station transceivers, have to work efficiently with respect to spectrum. Mobile radio channels are complicated due to multipath propagation, reflections, scattering, time, or frequency dispersion, etc. Sitting in an office environment surfing the Internet calls for a different solution for mobile communications than traveling in a train at a velocity of 200 km/h while engaged in a phone call. This is one of the reasons for the multitude of air interfaces which have been developed in recent years.

Mobile communications is based upon transmission standards, e.g. the air interface as well as the protocol stack of transmissions are at least agreed upon by the actual communications partners. A standard completely describes how a signal looks on air and which procedures are used to set up, maintain, and to close down a connection. Therefore it seems natural to ask whether there are construction principles that are common to all standards and, if so, to describe the standards according to these principles.

If a terminal in mobile communications has sufficiently flexible hardware at its disposal, it can ...