Patent ID: 11942981
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 12:
13. A control circuit that controls a receiver and causes the receiver to execute:
calculation of a first cross-correlation function between a received signal and an up chirp and calculation of a second cross-correlation function between the received signal and a down chirp, the received signal being a signal transmitted from a transmitter and having a preamble spread with the up chirp that is a spread code whose frequency increases with time and the down chirp that is a spread code whose frequency decreases with time;
calculation of first power values of the first cross-correlation function and calculation of second power values of the second cross-correlation function;
storage of the first power values and the second power values at each sample timing for one period of the spread code;
determination of a first estimated timing for the up chirp from the first power values for one period of the spread code, and determination of a second estimated timing for the down chirp from the second power values for one period of the spread code; and
estimation of a spread code timing of the transmitter using the first estimated timing and the second estimated timing, and coarse estimation of a frequency offset with respect to the transmitter.