US 12,506,651 B2 · Method and device for synchronization

Abstract

For radio transmission via OFDM (Orthogonal Frequency Division Multiplex) and TDMA (Time Division Multiple Access), it is important to have at the receiver the exact carrier frequency, and further to perform time synchronization. For time synchronization and simultaneous detection of a carrier frequency offset, a complex-valued synchronization sequence such as e.g. a Zadoff-Chu-sequence is transmitted twice: first in its original version and then, after a predefined time span, in its complex conjugate version. At the receiver, the two corresponding correlation maxima are detected by cross-correlation, and the time span between the maxima is measured. The measured time span is compared to the predefined time span and a time offset is determined. The time offset can be used to improve the synchronization accuracy and to determine the carrier frequency offset.

Claims16

Dependent claims

A method for synchronizing a receiver by using a received signal, the received signal comprising a synchronization sequence that comprises at least two complex-valued partial sequences, the method comprising:

performing a cross-correlation of the received signal against a first reference sequence that corresponds to a first partial sequence of the at least two complex-valued partial sequences, wherein a first correlation maximum is detected at a first point in time;
performing a cross-correlation of the received signal against a second reference sequence that corresponds to a second partial sequence of the at least two complex-valued partial sequences and that is a complex conjugate version of the first reference sequence, wherein a second correlation maximum is detected at a second point in time;
measuring a time span between the first point in time and the second point in time;
determining a time offset from the difference between the measured time span and a known time span;
and
time synchronizing the receiver, wherein at least one of the first and the second point in time is corrected by the determined time offset.

3 more elements

A device for synchronizing a receiver by using a received signal, the received signal comprising a synchronization sequence that comprises at least two complex-valued partial sequences, the device comprising:

a correlator configured for performing a cross-correlation of the received signal against a first reference sequence corresponding to a first partial sequence of the at least two complex-valued partial sequences, wherein a first correlation result is output upon a first correlation maximum being detected at a first point in time, and further configured for performing a cross-correlation of the received signal against a second reference sequence corresponding to a second partial sequence of the at least two complex-valued partial sequences, the second reference sequence being a complex conjugate version of the first reference sequence, wherein a second correlation result is output upon a second correlation maximum being detected at a second point in time;
and
a time control unit configured for receiving the first and second correlation results and further configured for measuring a time span between the first and the second point in time, and further configured for determining a time offset from a difference between the measured time span and a known time span;
wherein the receiver is time synchronized by setting a clock according to at least one of the first and the second point in time, corrected by the determined time offset.

1 more element

Dependencies are inferred from the claim text.

Method and device for synchronization

Life of this patent

Method and device for synchronization

Life of this patent

Abstract

Claims16