System and method for blind channel estimation and coherent differential equalization in an orthogonal frequency division multiplexing (ofdm) receiver

Patent metadata

Field	Value
Publication number	US-2025233777-A1
Application number	US-202418978389-A
Country	US
Kind code	A1
Filing date	Dec 12, 2024
Priority date	Dec 17, 2020
Publication date	Jul 17, 2025
Grant date	—

Abstract

In one aspect, an apparatus includes: a fast Fourier transform (FFT) engine to receive and convert a plurality of orthogonal frequency division multiplexing (OFDM) samples into a plurality of frequency carriers; a detector coupled to the FFT engine to determine a channel estimate for a first frequency carrier using a first channel estimate for the first frequency carrier and a plurality of other channel estimates, each of the plurality of other channel estimates for one of a plurality of neighboring frequency carriers within an evaluation window, and determine a log likelihood ratio (LLR) for the first frequency carrier using the channel estimate for the first frequency carrier; and a decoder coupled to the detector to decode a first OFDM symbol comprising the first frequency carrier using the LLR for the first frequency carrier.

First claim

1 . (canceled)

2 . A wireless receiver comprising:
a front end circuit to receive and process radio frequency signals into frequency domain data; and processing circuitry configured, based on the frequency domain data, to determine a log likelihood ratio for a first frequency carrier.

3 . The wireless receiver of claim 2 wherein the processing circuitry is further configured to decode encoded information in the frequency domain data using the log likelihood ratio.

4 . The wireless receiver of claim 3 wherein the processing circuitry is configured to use the log likelihood ratio as a soft decision to decode the encoded information.

5 . The wireless receiver of claim 3 wherein the processing circuitry is configured to perform coherent demodulation for a differentially encoded quadrature phase shift keying orthogonal frequency division multiplexing symbol.

6 . The wireless receiver of claim 2 wherein the processing circuitry is further configured to determine a channel estimate for the first frequency carrier by calculating an average using a first channel estimate for the first frequency carrier and one or more other channel estimates for one or more neighboring frequency carriers.

7 . The wireless receiver of claim 2 wherein the processing circuitry is further configured to:
calculate a plurality of metrics for the first frequency carrier and one or more neighboring frequency carriers; and
determine the log likelihood ratio based at least in part on the plurality of metrics.

8 . The wireless receiver of claim 2 wherein the processing circuitry is implemented in a programmable controller.

9 . The wireless receiver of claim 2 wherein the processing circuitry is implemented in dedicated hardware circuitry.

10 . A method of operating a wireless receiver comprising:
receiving radio frequency signals with a front end circuit of the wireless receiver, and converting the radio frequency signals into frequency domain data; and determining, with processing circuitry of the wireless receiver, based on the frequency domain data, a log likelihood ratio for a first frequency carrier.

11 . The method of claim 10 further comprising, with the processing circuitry, decoding encoded information in the frequency domain data using the log likelihood ratio.

12 . The method of claim 11 wherein the processing circuitry is configured to use the log likelihood ratio as a soft decision to decode the encoded information.

13 . The method of claim 11 further comprising, with the processing circuitry, performing coherent demodulation for a differentially encoded quadrature phase shift keying orthogonal frequency division multiplexing symbol.

14 . The method of claim 10 further comprising, with the processing circuitry, determining a channel estimate for the first frequency carrier by calculating an average using a first channel estimate for the first frequency carrier and one or more other channel estimates for one or more neighboring frequency carriers.

15 . The method of claim 10 further comprising, with the processing circuitry:
calculating a plurality of metrics for the first frequency carrier and one or more neighboring frequency carriers; and
determining the log likelihood ratio based at least in part on the plurality of metrics.

16 . The method of claim 10 wherein the processing circuitry is implemented in a programmable controller.

17 . The method of claim 10 wherein the processing circuitry is implemented in dedicated hardware circuitry.

18 . A wireless receiver comprising:
a front end circuit to receive and process radio frequency signals into frequency domain data; a processing circuitry configured, based on the frequency domain data, to determine a plurality of channel estimates for a plurality of frequency carriers, and to determine a soft decision for a first frequency carrier using the plurality of channel estimates, the processing circuitry further configured to perform coherent demodulation for a differentially encoded quadrature phase shift keying orthogonal frequency division multiplexing symbol to using the soft decision.

19 . The wireless receiver of claim 18 wherein the processing circuitry is further configured to:
calculate a plurality of metrics for the first frequency carrier and one or more neighboring frequency carriers; and
determine a soft decision for the first frequency carrier based at least in part on the plurality of metrics.

20 . The wireless receiver of claim 18 wherein the processing circuitry is implemented in a programmable controller.

21 . The wireless receiver of claim 18 wherein the processing circuitry is implemented in dedicated hardware circuitry.

Assignees

• Skyworks Solutions Inc

Inventors

• Kleinerman Alexander
• Wallace Bradley Arthur

Classifications

• H04L25/0236

  using estimation of the other symbols · CPC title

• H04L25/067

  providing soft decisions, i.e. decisions together with an estimate of reliability (H04L25/068 and H04L25/069 take precedence; sequence estimation techniques H04L25/03178) · CPC title

• H04L25/0204

  of multiple channels · CPC title

• H04L27/2636

  with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM] · CPC title

• H04L27/2647

  Arrangements specific to the receiver only (equalisation H04L27/01) · CPC title