Effective Estimation of Integer Carrier Frequency Offset in LTE Downlink Systems With Symbol Timing Error

Abstract

An effective integer carrier frequency offset (IFO) detection scheme is proposed in the long-term evolution downlink system without relying on the knowledge of the cell ID (CID) that is carried through the synchronization signal. To enable IFO detection without relying on the CID, the proposed IFO detection method utilizes the symmetric property of the synchronization signal, such as the primary synchronization signal (PSS) and the secondary synchronization signal (SSS). This design avoids the need to retrieve the CID that is carried by the PSS and the SSS at the IFO-matching stage. In addition to investigating the usefulness of the proposed IFO detection method, the probability of detection failure is theoretically calculated. The simulation results demonstrate that both the synchronization signals are effectively exploited for the robust detection of the IFO in the presence of non-negligible symbol timing error, where the conventional approaches show unsatisfactory performance.