Universal Classifier Synchronizer Demodulator

A Universal Classifier Synchronizer and Demodulator (UCSD) is conceived as a self-contained system which forms the heart of a truly cognitive receiver. It can automatically interpret features of the received signal to accomplish physical layer classification, synchronization and demodulation without any priori information about the waveform from the transmitter side. In this paper we propose a cognitive receiver functioning as a finite state machine. The accommodated modulations include AM, FM, FSK, MPSK, and QAM. The designed system has been verified using a stand-alone MATLAB-enabled Anritsu MS2781A Signature Signal Analyzer running Windows, and GNU Radio plus a Universal Software Radio Peripheral (USRP) in Linux.

I. Introduction

Signal classification has many applications in wireless communications for both civilian and military purposes. Most of the time, it is posed as an M-ary hypothesis testing problem. In our system, however, we are not only focusing on the type of the signal, but also detecting its physical layer features. The proposed UCSD has the ability to demodulate signals without benefit of any priori information and forms the heart of a truly cognitive receiver. Our software-based design at IF or quasi-baseband realizes a universal classification, synchronization and demodulation algorithm to meet a cognitive radio receiver's requirements for automatic configuration.