Blind MC-DS-CDMA Parameters Estimation in Frequency Selective Channels

An apportunistic or cognitive radio system needs accurate knowledge of the radio spectrum it operates. The concept of cognitive radio is also exploited in the railway context in order to satisfy high availability and interoperability of wireless telecommunication systems everywhere as required by operational or safety applications deployed by the railway operator. It allows for example dynamic spectrum allocation versus QoS (Quality of service) or traffic requirements and very often spectrum reuse especially in rural areas. Blind multi-carrier transmission recognition methods based on the discrimination between single-carrier and multi-carrier modulations to estimate their parameters have been addressed in the literature. Some powerful techniques use autocorrelation and cyclic autocorrelation based features of the transmitted signal. In this paper, we propose a blind parameter estimation based on analysis of fluctuations of autocorrelation estimators which was initially employed in CDMA signals interception. The proposed technique leads to a fast efficient parameters estimation and is insensitive to receiver phase and frequency offsets as it is highlighted in simulation results.