Systems and methods for timing recovery in near-field communication
AssigneeQUALCOMM Incorporated
InventorsEunmo Kang, Le Nguyen Luong, Koorosh Akhavan, Rajapaksa Senaratne, Thomas Cargill
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Abstract
A method for inductively-coupled communications is described. The method includes receiving a signal. The method also includes analyzing the signal to estimate a symbol timing error. Estimating the symbol timing error may include comparing a location of a pause, a low-to-high or a high-to-low transition in the received signal with an ideal location of a pause or a transition. The method further includes adjusting symbol timing to correct for the symbol timing error.
Claims20
A method for inductively-coupled communications, comprising:
- receiving a signal from an inductively coupled communication device;
- analyzing the signal to estimate a symbol timing error, comprising:
- summing multiple samples in a first portion of the signal for a bit to form a first sum;
- summing multiple samples in a second portion of the signal for the bit to form a second sum;
- determining the symbol timing error based on at least the first sum and the second sum;
- and
- adjusting symbol timing to correct for the symbol timing error by adding or subtracting the estimated symbol timing error from a sample counter that counts samples from a start of a symbol.
A receiver for inductively-coupled communications, comprising:
- a receive antenna for receiving a signal from an inductively coupled communication device;
- a slicer that receives output samples from an analog-to-digital converter and generates a bit stream;
- an acquisition block that acquires packets and initial symbol timing;
- a decoder;
- and
- a time tracker block that analyzes the signal to estimate a symbol timing error based on the initial symbol timing and the bit stream and adjusts symbol timing to correct for the symbol timing error by adding or subtracting the estimated symbol timing error from a sample counter that counts samples from a start of a symbol, wherein the time tracker block provides the symbol timing to the decoder, wherein the time tracker block analyzes the signal by:
- summing multiple samples in a first portion of the signal for a bit to form a first sum;
- summing multiple samples in a second portion of the signal for the bit to form a second sum;
- determining the symbol timing error based on at least the first sum and the second sum.
A computer-program product for inductively-coupled communications, the computer-program product comprising a non-transitory computer-readable medium having instructions thereon, the instructions comprising:
- code for causing an electronic device to receive a signal from an inductively coupled communication device;
- code for causing the electronic device to analyze the signal to estimate a symbol timing error, comprising:
- code for summing multiple samples in a first half of a portion of the signal for a bit to form a first sum;
- code for summing multiple samples in a second half of the portion of the signal for the bit to form a second sum;
- code for determining the symbol timing error based on at least the first sum and the second sum;
- and
- code for causing the electronic device to adjust symbol timing to correct for the symbol timing error by adding or subtracting the estimated symbol timing error from a sample counter that counts samples from a start of a symbol.
Dependencies are inferred from the claim text.