EURASIP Journal on Applied Signal Processing 
Volume 2005 (2005), Issue 16, Pages 2708-2718
doi:10.1155/ASP.2005.2708

Blind I/Q Signal Separation-Based Solutions for Receiver Signal Processing

Mikko Valkama,1 Markku Renfors,1 and Visa Koivunen2

 1Institute of Communications Engineering, Tampere University of Technology, P.O. Box 553, Tampere 33101, Finland
2Signal Processing Laboratory, Helsinki University of Technology, P.O. Box 3000, 02015 HUT, Finland
Received 5 February 2004; Revised 14 October 2004

Abstract

This paper introduces some novel digital signal processing (DSP)-based approaches to some of the most fundamental tasks of radio receivers, namely, channel equalization, carrier synchronization, and I/Q mismatch compensation. The leading principle is to show that all these problems can be solved blindly (i.e., without training signals) by forcing the I and Q components of the observed data as independent as possible. Blind signal separation (BSS) is then introduced as an efficient tool to carry out these tasks, and simulation examples are used to illustrate the performance of the proposed approaches. The main application area of the presented carrier synchronization and I/Q mismatch compensation techniques is in direct-conversion type receivers, while the proposed channel equalization principles basically apply to any radio architecture.