Signal Design for Reduced Complexity and Accurate Cell Search/Synchronization in OFDM-Based Cellular Systems

Abstract

This paper proposes a variant of the frequency-domain synchronization structure specified in the long-term evolution (LTE) standard. In the proposed scheme, the primary synchronization signal used in step-1 cell search is the concatenation of a Zadoff-Chu (ZC) sequence and its conjugate (as opposed to only the ZC sequence in LTE). For step-2 cell search, we propose a complex scrambling sequence requiring no descrambling and a new remapped short secondary synchronization signal that randomizes the intercell interference (as opposed to the first/second scrambling sequence and swapped short signals in LTE). Through a combination of analysis and simulation, we demonstrate that the proposed synchronization signals lead to lower searcher complexity than LTE, a lower detection error rate, a shorter mean cell search time, and immunity toward a frequency offset.