Synchronization control and compensation of STO and CFO by sub-sampling method

Abstract

In uplink orthogonal frequency division multiple access (OFDMA) systems, available subcarriers are divided into groups and assigned to multiple uses for simultaneous transmissions. The ideal universal receiver sampling the incoming signals just after a RF stage is very seducing but not realistic at this time due to limitations in sampling capabilities for high frequency systems. Software-defined radio (SDR) principles have attracted more and more attention. As one way, using sub-sampling technique can convert multi-bands signals from RF band to IF band without oscillator. But as the filter performance in RF band, signals converted in low band possibly cause interference and degrades performance. In this paper, we propose one method that uses time division multiplexing (TDM) method as a solution to avoid interference. Combining TDM with sub-sampling at the same can get signals without large changes from the existing structures. © 2012 Springer-Verlag.