Robust OFDM-Based Synchronization Against Very High Fractional CFO and Time-Varying Fading

Abstract

This article investigates the advantages and disadvantages of cell search for LTE and NR. This investigation enables us to design a couple of synchronization signals specified in frequency domain for a whole of cell search. For time/frequency synchronization and partial cell identification, to achieve both low complexity and robustness against very high carrier frequency offset (CFO) and time-varying fading, we propose a primary synchronization signal generated by the centrally symmetric concatenation of a Zadoff-Chu sequence and its modified sequence. Also, for final cell identification, to minimize intercell interference, we propose a secondary synchronization signal constructed by element-wise exclusive-OR operation of two different cyclic-shifted m-sequences. By complexity, intercell interference analysis, and accuracy-optimized searching description, as well as cell-search evaluation, we elucidate that the proposed scheme provides many advantages, such as lower complexity, immunity toward CFO and mobility, and shorter mean cell search time directly related with latency and battery life.