In this study, the authors propose a low-complexity method for symbol synchronisation in the third generation partnership project long term evolution (LTE) downlink system. The authors introduce the lowest sampling frequency of a receiver for synchronisation purposes. Using a low sampling frequency at the receiver means that the digital signal is decimated and a lower number of processing samples is needed. This results in reducing the computational complexity. It is also shown that this advantage comes at the cost of signal-to-noise ratio degradation and insertion of a systematic error in synchronisation that can be avoided by choosing a proper decimation factor. A thorough analysis is also conducted for all possible sampling frequencies that reduce the computational complexity of LTE cell search. To show the validity of the authors' method, they implemented an LTE primary synchroniser in C++ using GNU Radio libraries and prepared a software-based radio modem, tested in different conditions. Some Monte-Carlo simulations are carried out to compare the proposed method with other low-complexity methods. These comparisons show the suggested method is faster than available techniques in literatures.