Patent ID: 9025569
Filing Date: 2015-05-05
Classification: H04B,H04W

Abstract:
1. A method of acquiring downlink frame synchronization in a code division multiple access mobile communication system, the method comprising: phase-rotating a mid-amble of a first Time Slot (TS) of a received sub-frame within an area and estimating a Channel Impulse Response (CIR); calculating a Maximum Likelihood (ML) between a downlink synchronization code of the received sub-frame and a downlink synchronization code generated in a terminal by using the estimated CIR; correlating downlink synchronization codes of a plurality of sub-frames corresponding to M Transmission Time Intervals (TTIs) and the downlink synchronization code generated in the terminal and calculating ML values of the plurality of sub-frames; calculating hypothesis values of hypotheses according to a frequency interval and a phase offset of the downlink synchronization code generated in the terminal based on the calculated ML values of the plurality of sub-frames and drawing a frequency offset and a hypothesis corresponding to a maximum value among the calculated hypothesis values; and comparing a maximum value of the ML values with a threshold and determining that frame synchronization acquisition is successful when the maximum value of the ML values is larger than the threshold and the drawn hypothesis is included in a hypothesis indicating successful synchronization acquisition.