High-Precision Blind Carrier Synchronization Methods for LTE SC-FDMA Uplink

摘要

Methods and systems are described for frequency domain correction, time domain correction, and combinations thereof. Each Long Term Evolution (LTE) uplink residual frequency offset can be determined with less than 1 part per billion accuracy simultaneously and used for frequency offset correction. The disclosed method utilizes the same modulated signals for data and control as the 3GPP LTE wireless standard and can be embedded directly into the base station (downlink) PHY without additional hardware. The use of the disclosed methods provide multiple ways to simultaneously improve the uplink data throughput for every user in an LTE multiple access wireless system.

主权项

1. A method for blind carrier synchronization, comprising:
applying an N-point discrete Fourier transform (DFT) to a received time domain signal to produce a frequency domain signal; using a channel schedule to select portions of the frequency domain signal that correspond to signals received from a single user equipment (UE); applying a first frequency offset and a first phase offset to the selected portions of the frequency domain signal to produce a frequency and phase offset corrected frequency domain signal; applying an M-point inverse discrete Fourier transform (IDFT) to a frequency and phase offset corrected frequency domain signal based on the selected portions of the frequency domain signal to produce an intermediate time domain signal; computing a correlation function of I and Q samples of the portions of the intermediate time domain signal over a range of frequency offset values and a range of phase offset values to iteratively search for a global maximum of the correlation function; identifying the global maximum of the correlation function over the range of frequency offset values and the range of phase offset values; and applying a final frequency offset and a final phase offset to the portions of the received time domain signal based on the identified global maximum.