Apparatus and method for high-speed synchronization in wireless communication
A method includes calculating first correlation values corresponding to a first symbol duration based on input samples, the input samples being generated from a received signal; calculating phase differences respectively corresponding to the input samples based on the first correlation values and second correlation values corresponding to a second symbol duration preceding the first symbol duration; updating accumulative phase differences respectively corresponding to the input samples based on the phase differences; and detecting a symbol boundary based on the updated accumulative phase differences.
1 . A method comprising:
calculating first correlation values corresponding to a first symbol duration based on input samples, the input samples being generated from a received signal;
calculating phase differences respectively corresponding to the input samples based on the first correlation values and second correlation values corresponding to a second symbol duration preceding the first symbol duration;
updating accumulative phase differences respectively corresponding to the input samples based on the phase differences; and
detecting a symbol boundary based on the updated accumulative phase differences.
2 . The method of claim 1 , wherein the first correlation values and the second correlation values are complex numbers,
wherein calculating the phase differences comprises:
obtaining a first correlation value from the first correlation values and a second correlation value from the second correlation values, the first correlation value and the second correlation value corresponding to a same index of an input sample;
calculating a complex conjugate of the obtained second correlation value; and
multiplying the obtained first correlation value by the calculated complex conjugate of the obtained second correlation value.
3 . The method of claim 1 , wherein the phase differences and the accumulative phase differences are complex numbers,
wherein updating the accumulative phase differences comprises:
obtaining a phase difference from the phase differences and an accumulative phase difference from the accumulative phase differences, the phase difference and the accumulative phase difference corresponding to a same index of an input sample; and
summing the obtained phase difference and the obtained accumulative phase difference.
4 . The method of claim 3 , wherein updating the accumulative phase differences further comprises setting the accumulative phase difference to zero when the first symbol duration is an initial symbol duration.
5 . The method of claim 1 , wherein detecting the symbol boundary comprises:
updating accumulative correlation values based on the first correlation values and the updated accumulative phase differences;
identifying a maximum value among the updated accumulative correlation values; and
determining an index of an input sample corresponding to the maximum value.
6 . The method of claim 5 , wherein updating the accumulative phase differences further comprises:
correcting the accumulative correlation value based on the updated accumulative phase difference; and
summing the first correlation value and the corrected accumulative correlation value.
7 . The method of claim 5 , wherein detecting the symbol boundary further comprises:
comparing the maximum value with a first reference value; and
when the maximum value is less than the first reference value, determining that the symbol boundary is undetectable.
8 . The method of claim 1 , wherein the detecting of the symbol boundary further comprises:
identifying a maximum value among the updated accumulative phase differences; and
determining an index of an input sample corresponding to the maximum value.
9 . The method of claim 8 , wherein detecting the symbol boundary further comprises:
comparing the maximum value with a second reference value; and
when the maximum value is less than the second reference value, determining that the symbol boundary is undetectable.
10 . The method of claim 1 , wherein each of the first symbol duration and the second symbol duration corresponds to a duration of a single symbol included in a SYNC field included in a synchronization header (SHR).
11 . An apparatus comprising:
a first buffer configured to store input samples generated from a received signal and corresponding to a first symbol duration;
a processing circuit configured to calculate first correlation values respectively corresponding to the input samples based on the input samples;
a second buffer configured to store second correlation values corresponding to a second symbol duration preceding the first symbol duration; and
a third buffer configured to store accumulative phase differences respectively corresponding to the input samples,
wherein the processing circuit is further configured to:
calculate phase differences respectively corresponding to the input samples, based on the first correlation values and the second correlation values;
update the accumulative phase differences based on the phase differences; and
detect a symbol boundary based on the updated accumulative phase differences.
12 . The apparatus of claim 11 , wherein the first correlation values and the second correlation values are complex numbers,
wherein the processing circuit is further configured to
read a second correlation value from the second buffer, the second correlation value corresponding to a same index of an input sample corresponding to a first correlation value; and
calculate the phase differences by multiplying the first correlation value by a complex conjugate of the read second correlation value.
13 . The apparatus of claim 11 , wherein the phase differences and the accumulative phase differences are complex numbers,
wherein the processing circuit is further configured to
read an accumulative phase difference from the third buffer, the accumulative phase difference corresponding to a same index of an input sample corresponding to one of the phase differences; and
update the accumulative phase differences by summing the one of the phase differences and the read accumulative phase difference.
14 . The apparatus of claim 13 , wherein the processing circuit is further configured to set the accumulative phase difference to zero when the first symbol duration is an initial symbol duration.
15 . The apparatus of claim 11 , wherein the processing circuit is further configured to
update accumulative correlation values based on the first correlation values and the updated accumulative phase differences;
identify a maximum value among the updated accumulative correlation values; and
determine an index of an input sample corresponding to the maximum value.
16 . The apparatus of claim 15 , further comprising: a fourth buffer configured to store accumulative correlation values,
wherein the processing circuit is further configured to
read the accumulative correlation value from the fourth buffer;
correct the read accumulative correlation value based on the updated accumulative phase difference; and
update the accumulative correlation values by summing the first correlation value and the corrected accumulative correlation value.
17 . The apparatus of claim 11 , wherein the processing circuit is further configured to determine an index of a input sample corresponding to a maximum value of the updated accumulative phase differences.
18 . The apparatus of claim 11 , wherein the processing circuit is further configured to identify a phase of a first correlation value corresponding to the detected symbol boundary, and determine the identified phase to be an initial phase.
19 . The apparatus of claim 11 , wherein the processing circuit is further configured to calculate a carrier frequency offset based on the first symbol duration and an accumulative phase difference corresponding to the detected symbol boundary.
20 . An apparatus comprising:
a memory storing a series of instructions; and
at least one processor configured to, by executing the series of instructions,
calculate first correlation values corresponding to a first symbol duration and respectively corresponding to input samples, the input samples being generated from a received signal;
calculate phase differences respectively corresponding to the input samples, based on the first correlation values and second correlation values corresponding to a second symbol duration preceding the first symbol duration;
update accumulative phase differences respectively corresponding to the input samples based on the phase differences; and
detect a symbol boundary based on the updated accumulative phase differences.