Cell Search Time Performance Using Multipath Signals in LTE Downlink

This paper presents cell search time performance using multipath signals in the Long-Term Evolution (LTE) downlink employing Orthogonal Frequency Division Multiple Access (OFDMA) in inter-cell site asynchronous operation. In the paper, we propose primary synchronization signal (PSS) detection using multipath signals based on window detection and secondary synchronization signal (SSS) detection using coherent summation of channel estimates weighted by the frequency domain channel response of typically assumed multipath signals. Computer simulation results show that the effect of using multipath signals for PSS detection on the overall cell search time performance is slight, and the maximum correlation peak detection for the PSS provides a sufficiently fast cell search time. The results also show that coherent averaging of channel estimates using the PSS to detect the eNode-B-specific SSS sequence is effective in achieving a fast cell search time, and the achievable cell search time is insensitive to the weighting factor as long as the interval of the coherent summation is optimized for the respective power delay profiles.