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US 8,942,222 B2Granted
Frequency synchronization in wireless communication systems
AssigneeAlcatel Lucent
InventorsRainer Bachl, Jung A. Lee
Life of this patent
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Abstract
The present invention provides a method of wireless communication over a communication link including at least one carrier that comprises a plurality of sub-carriers. The method includes modifying at least one frequency of at least one uplink sub-carrier in response to a signal indicating a modification of the frequency.
Claims16
A method of wireless communication over a communication link that comprises a plurality of sub-carriers, comprising:
- providing, from a mobile unit to a base station, a pilot signal on a random access channel of the communication link, wherein the pilot signal comprises a sounding reference signal comprising at least one reference symbol;
- and
- modifying, at the mobile unit, at least one frequency of at least one uplink sub-carrier in response to a signal transmitted to the mobile unit by the base station, the signal indicating a modification of said at least one frequency, the modification being determined by the base station based on a value of a frequency of the pilot signal measured at the base station, wherein the modification of said at least one frequency is determined by down-modulating the received frequency at an expected subcarrier frequency and estimating a frequency offset between the expected subcarrier frequency and said at least one frequency using autocorrelation properties of the at least one reference symbol in an equivalent complex baseband representation of the down-modulated signal.
A method of wireless communication over a communication link that comprises a plurality of sub-carriers, comprising:
- receiving, from a mobile unit at a base station, a pilot signal on a random access channel of the communication link, wherein the pilot signal comprises a sounding reference signal comprising at least one reference symbol;
- measuring, at the base station, a value of a frequency of the pilot signal;
- and
- providing, from the base station to the mobile unit, a signal indicating a modification of at least one frequency of at least one uplink sub-carrier of the communication link, the modification being determined by the base station based on the measured value of the frequency of the pilot signal and by down-modulating the received frequency at an expected subcarrier frequency and estimating a frequency offset between the expected subcarrier frequency and said at least one frequency using autocorrelation properties of the at least one reference symbol in an equivalent complex baseband representation of the down-modulated signal.
1 more element
Dependencies are inferred from the claim text.