Software Defined Radio: Architectures, Systems and Functions

12

Mode Identification and Monitoring of Available Air Interfaces

Georgios Vardoulias and Jafar Faroughi-Esfahani

Motorola Ltd

12.1 Problem Definition: Mode Monitoring and Identification of Air Interfaces

One can define three stages in any mobile phone's/terminal's activity time: (a) the first few seconds when the terminal is switched on and cannot make or accept any calls; (b) the period during which the terminal is able to communicate but there is no user activity; and finally (c) the period when the terminal is used in order to send/receive voice and data. This section is dedicated to stages (a) and (b). We will show that after keying in the PIN number, the terminal has to do a number of demanding tasks in a short time before we can actually use it. We will present the relevant GSM and UMTS procedures as an example of how things work today. This will be our guide in order to predict what the first few seconds of a Software Defined Radio (SDR) terminal will be like. Our intention is to present the problems, not the solutions. The software radio technology has many open (almost virgin) research areas and this is one of them.

As was pointed out in ref. [1],

a software radio terminal does not just receive: It

• Characterises the energy distribution in the channel and in adjacent channels
• Recognises the mode of the incoming transmission
• Adaptively nulls interferers
• Estimates the dynamic properties of desired-signal multipath
• Coherently combines desired-signal multipath
• Adaptively ...