# US 10,313,163 B2 · Wireless SC-FDMA communications system

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- Number: US 10,313,163 B2
- Document ID: US10313163B2
- Status: Granted
- Kind: B2
- Application number: 16/008,821
- Filed: 2018-06-14
- Published: 2018-10-18
- Granted: 2019-06-04
- Earliest claimed: 2015-05-28
- Assignees: King Fahd University of Petroleum and Minerals
- Applicants: King Fahd University of Petroleum and Minerals
- Inventors: Naveed Iqbal; Azzedine Zeguine
- Web page: https://patentgrep.com/patent/US10313163B2

## CPC

- H04L 25/03159: {operating in the frequency domain (H04L25/03165, H04L25/03178 take precedence)}
- H04B 7/2621: {using frequency division multiple access [FDMA] (H04B7/2615 takes precedence)}
- H04L 1/0606: {Space-frequency coding}
- H04L 1/0631: {Receiver arrangements}
- H04L 25/03057: {with a recursive structure (H04L25/03031 takes precedence)}
- H04L 25/03146: {with a recursive structure (H04L25/03127 takes precedence)}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION

## Abstract

A device includes circuitry configured to determine feedforward and feedback coefficients for an adaptive frequency-domain decision feedback equalizer (AFD-DFE) based on previously received signals. The equalizer output is determined by applying the feedforward and feedback coefficients of the AFD-DFE to a received signal, and the feedforward and feedback coefficients of the AFD-DFE are updated based on the equalizer output.

## Claims

### Claim 1

A wireless device SC-FDMA communications system, comprising:
a wireless device comprising a transmitter to transmit an RF signal, and
a base station comprising a receiver to receive the RF signal,
wherein the wireless device comprises circuitry configured to
generate a plurality of signal matrices based on received signals,
determine feedforward coefficients for an adaptive frequency-domain decision feedback equalizer (AFD-DFE) based in part on the signal matrices,
generate a plurality of decision matrices based on transformed feedforward coefficients,
determine feedback coefficients for the AFD-DFE based in part on the plurality of decision matrices,
generate a first matrix having the plurality of signal matrices and the decision matrices,
generate a second matrix including the feedforward coefficients and a third matrix including the feedback coefficients of the AFD-DFE,
determine an equalizer output as a function of the first matrix, the second matrix and the third matrix such that the function includes adding a first product comprising the plurality of signal matrices premultiplied by a variation of the second matrix and a second product comprising the plurality of decision matrices being premultiplied by a variation of the third matrix, wherein the equalizer output is determined for Spatially-Multiplexed (SM)SC-FDMA signals
update the feedforward and feedback coefficients of the AFD-DFE based on the equalizer output,
equalize the received signals using the equalizer output, and
decode the equalized signals.

### Claim 2 (depends on 1)

The wireless device SC-FDMA communications system of claim 1, wherein the circuitry is further configured to determine the feedforward and feedback coefficients based on a recursive least squares (RLS) calculation.

### Claim 3 (depends on 2)

The wireless device SC-FDMA communications system of claim 2, wherein the circuitry is further configured to determine the RLS calculation with at least one constraint.

### Claim 4 (depends on 1)

The wireless device SC-FDMA communications system of claim 1, wherein the circuitry is further configured to apply a three-tap AFD-DFE to the received signal.

### Claim 5 (depends on 1)

The wireless device SC-FDMA communications system of claim 1, wherein the circuitry is further configured to operate in a reduced training mode wherein a number of symbols in a training signal used to update the feedforward and feedback filter coefficients of the AFD-DFE is reduced.

### Claim 6 (depends on 1)

The wireless device SC-FDMA communications system of claim 1, wherein the circuitry is further configured to determine the equalizer output for Single-Input Single-Output (SISO) Single-Carrier Frequency Division Multiple Access (SC-FDMA) signals.

### Claim 7 (depends on 1)

The wireless device SC-FDMA communications system of claim 1, wherein the circuitry is further configured to determine the equalizer output within a predetermined performance threshold when carrier frequency offset is present.

### Claim 8 (depends on 1)

The wireless device SC-FDMA communications system of claim 1, wherein the circuitry is further configured to determine the equalizer output within a predetermined performance threshold when Doppler is present.

### Claim 9 (depends on 1)

The wireless device SC-FDMA communications system of claim 1, wherein the circuitry is further configured to update the feedforward and feedback coefficients of the AFD-DFE by performing one or more scalar multiplications corresponding to at least one of a number of data symbols in the received signal and a number of transmit antennas.