Frequency estimation and tracking in a receiver
AssigneeQUALCOMM Incorporated
InventorsKoorosh Akhavan, Eunmo Kang, Rajapaksa Senaratne
Life of this patent
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Abstract
In one aspect, a method for estimating residual carrier frequency offset (CFO) in a phase-modulated wireless signal having pseudo noise (PN) spreading is provided. The method includes receiving, at a digital transceiver, a plurality of PN spread blocks of in-phase and quadrature (I/Q) samples of the phase-modulated wireless signal and performing sample-level de-rotation, symbol-level de-spreading, and sign alignment. The method also includes estimating a phase difference and determining an estimated residual CFO based on the phase difference.
Claims20
A method for estimating residual carrier frequency offset (CFO) in a phase-modulated wireless signal having pseudo noise (PN) spreading, the method comprising:
- receiving, at a digital transceiver, a plurality of PN spread blocks of in-phase and quadrature (I/Q) samples of the phase-modulated wireless signal;
- performing sample-level de-rotation during a respective modulated symbol period;
- performing symbol-level de-spreading;
- performing sign alignment;
- estimating a phase difference;
- and
- determining an estimated residual CFO based on the phase difference.
A wireless device, comprising:
- a digital transceiver;
- memory adapted to store program code;
- and
- a processor coupled to the memory to access and execute instructions included in the program code to direct the wireless device to:
- receive, at the digital transceiver, a plurality of pseudo noise (PN) PN spread blocks of in-phase and quadrature (I/Q) samples of the phase-modulated wireless signal;
- perform sample-level de-rotation during a respective modulated symbol period;
- perform symbol-level de-spreading;
- perform sign alignment;
- estimate a phase difference;
- and
- determine an estimated residual CFO based on the phase difference.
A non-transitory computer-readable medium including program code stored thereon for performing wireless communications by a wireless device, the program code comprising instructions to:
- receive, at a digital transceiver of the wireless device, a plurality of pseudo noise (PN) spread blocks of in-phase and quadrature (I/Q) samples of the phase-modulated wireless signal;
- perform sample-level de-rotation and accumulation of the I/Q samples during a respective modulated symbol period of the I/Q samples;
- perform symbol-level de-spreading within each of the plurality of PN spread blocks to generate de-spread blocks;
- perform sign alignment on the de-spread blocks to generate sign-aligned blocks;
- estimate a phase difference between two or more adjacent sign-aligned blocks;
- and
- determine an estimated residual CFO based on the phase difference.
Dependencies are inferred from the claim text.