Downlink LTE synchronization: A software defined radio approach

In this paper we examine the performance of traditional and non-traditional time-frequency synchronization workflows for LTE FDD downlink. The effectiveness of each synchronization workflow is evaluated using a software defined radio (SDR) platform in an indoor environment under varying carrier frequency offsets (CFO) and received power conditions. We reveal traditional workflows are highly suitable for environments with minimal CFO and non-traditional workflows, exploiting the conjugate symmetric nature of the secondary synchronization signal (SSS), are suitable in high CFO environments. In addition, we propose a metric for LTE subframe timing that jointly estimates the position of the primary synchronization signal (PSS) and the PSS root index. Unlike many methods for detecting the PSS, the metric proposed is theoretically invariant to CFO at medium to high SNR ranges.