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US 2006/0140257 A1Published application
Method for carrier frequency offset fine estimation in TD-SCDMA system
AssigneeSpreadtrum Communications Corporation
InventorJiwu Liu
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Abstract
A simple and efficient method is provided for frequency offset fine estimation. The method comprises: subtracting the QPSK modulation phase of a synchronization code from its received phase to generate the phase drift, and then computing the frequency offset based on the phase drift.
Claims4
A method for frequency offset fine estimation in a TD-SCDMA system comprising:
- subtract a QPSK modulation phase of a transmitted sequence from its operational phase to generate a phase drift;
- determining the frequency offset based on the phase drift.
A method of frequency offset fine estimation comprising:
- completing a cell search process and reading a BCH message;
- determining a P-CCPCH position;
- based upon the P-CCPCH position determining whether sequence S1 or S2 is present by if a P-CCPCH is present in a next superframe, sequence S1 is ascertained and if there is no such P-CCPCH is present in said next superframe, sequence S2 is ascertained;
- determining a QPSK modulation of the SYNC-DL code based upon the sequence determined;
- measuring the phase of the received SYNC-DL sequence;
- substracting the QPSK modulation from an operational phase to determine a phase drift;
- and
- deriving the frequency offset using the phase drift with the equation of Δφ=Δf* T, where Δφ is phase drift, Δf represents frequency offset and T denotes sequence duration.
5 more elements
Dependencies are inferred from the claim text.