Compensation for local oscillator errors in an OFDM receiver

• US 5,838,734 A
• Filed: 03/26/1996
• Issued: 11/17/1998
• Est. Priority Date: 05/05/1993
• Status: Expired due to Term

• Current Assignee: British Broadcasting Corporation
• Original Assignee: British Broadcasting Corporation
• Inventors: Wright, Derek Thomas
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US08/549,831
• Time in Patent Office: 966 Days
• Field of Search: 375/260, 375/341, 375/340, 375/262, 375/200, 375/316, 375/346, 375/326, 370/208, 370/206, 348/725
• US Class Current: 375/316
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2679 Decision-aided
• CPC Class Codes: H04L 27/3455 in order to facilitate carrier recovery at the receiver end, e.g. by transmitting a pilot or by using additional signal points to allow the detection of rotations

Abstract

A receiver for orthogonal frequency division multiplexed signals includes means (14) for calculating the (discrete) Fourier Transform of the received signal, and means (20) for calculating the phase error due to local oscillator errors.

Claims

1. A receiver for an orthogonal frequency division multiplexed signal comprising:

means for receiving a Fourier transform (FT) representation of the signal,

inverse Fourier transform means for converting the FT to the frequency domain,

means for deriving magnitude and phase of each frequency domain component of the inverse FT,

means for analyzing the phase of the frequency domain component;

means for compensating for phase errors common to all carriers in one Fourier Transform symbol wherein the phase errors comprise phase noise from a local oscillator.

2. A receiver for an orthogonal frequency division multiplexed signal according to claim 1 in which the received signal comprises a television signal.

3. A receiver for an orthogonal frequency division multiplexed signal according to claim 1, in which the received signal comprises an FT of a quadrature amplitude modulation signal (QAM).

4. A receiver for an orthogonal frequency division multiplexed signal according to claim 1, in which the analyzing means operates by a maximum likelihood decoding technique.

5. A receiver for an orthogonal frequency division multiplexed signal according to claim 1, in which the analyzing means operates by a majority voting technique.

6. A receiver for an orthogonal frequency division multiplexed signal according to claim 1, in which the Fourier Transform is a Discrete Fourier Transform.

7. A receiver for an orthogonal frequency division multiplexed signal according to claim 1, in which the Fourier Transform is a Fast Fourier Transform.

8. A receiver for an orthogonal frequency division multiplexed signal comprising:

means for receiving a Fourier Transform (FT) representation of the signal;

inverse Fourier Transform means for converting the FT to the frequency domain;

means for deriving magnitude and phase of each frequency domain component of the inverse FT;

means for analyzing the phase of the frequency domain component by a maximum likelihood decoding technique; and

means for compensating phase errors common to all carriers in one Fourier Transform symbol.

9. A receiver for an orthogonal frequency division multiplexed signal comprising:

means for receiving a Fourier Transform (FT) representation of the signal;

inverse Fourier Transform means for converting the FT to the frequency domain;

means for deriving magnitude and phase of each frequency domain component of the inverse FT;

means for analyzing the phase of the frequency domain component by a majority voting technique; and

means for compensating for phase errors common to all carriers in one Fourier Transform symbol.