# US 12,119,977 B1 · System and method for joint radar-sensing and communication waveform utilizing unique word OFDM (UW-OFDM)

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- Number: US 12,119,977 B1
- Document ID: US12119977B1
- Status: Granted
- Kind: B1
- Application number: 18/119,925
- Filed: 2023-03-10
- Granted: 2024-10-15
- Earliest claimed: 2020-12-07
- Assignees: University of South Florida
- Applicants: University of South Florida
- Inventors: Huseyin Arslan; Mehmet Mert Sahin
- Web page: https://patentgrep.com/patent/US12119977B1

## CPC

- H04L 27/2605: {Symbol extensions, e.g. Zero Tail, Unique Word [UW]}
- H04L 27/2634: {Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation}
- G01S 7/006: {using shared front-end circuitry, e.g. antennas (G01S13/765, G01S13/825 take precedence)}
- G01S 13/343: {using sawtooth modulation}
- G01S 13/38: wherein more than one modulation frequency is used
- G01S 13/931: of land vehicles
- H04B 1/69: Spread spectrum techniques
- H04B 2001/6912: {using chirp}
- H04W 16/28: using beam steering
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A system and method utilizing a novel waveform structure based on unique word (UW)-orthogonal frequency division multiplexing (OFDM) is proposed for the applications of joint radar-sensing and communication (JRC). A predetermined chirp sequence is used as the UW in the waveform. The predetermined chirp sequence is used to perform radar functionality, which also increases power efficiency of linear power amplifier that is critical for radar applications.

## Claims

### Claim 1

A method for assembling unique word (UW)-orthogonal frequency division multiplexing (OFDM) data symbols for use in joint radar-sensing and communication (JRC), the method comprising:
generating OFDM time domain symbols at an output of an N-point inverse fast Fourier transformation (IFFT) block of a transmitter; and
adding a predetermined chirp sequence in the OFDM time domain symbols to assemble UW-OFDM symbols having a chirp sequence, wherein the UW is the predetermined chirp sequence for joint radar-sensing and communication (JRC).

### Claim 2 (depends on 1)

The method of claim 1, wherein the OFDM time domain symbols comprise Nu zeroes and wherein Nu is an integer greater than one.

### Claim 3 (depends on 1)

The method of claim 1, wherein the predetermined chirp sequence forms a tail of each of the OFDM time domain symbols.

### Claim 4 (depends on 1)

The method of claim 1, wherein generating the OFDM time domain symbols at the output of the N-point inverse fast Fourier transformation (IFFT) block further comprises:
providing OFDM frequency domain symbols to a code generator matrix to introduce redundancy into the OFDM frequency domain symbols; and
modulating the OFDM frequency domain symbols having redundancy on a plurality of subcarriers using the IFFT block to generate the OFDM time domain symbols.

### Claim 5 (depends on 3)

The method of claim 3, wherein the redundancy introduced into the OFDM frequency domain by the code generator matrix is distributed over the plurality of subcarriers.

### Claim 6 (depends on 1)

The method of claim 1, wherein the JRC is mono-static JRC.

### Claim 7 (depends on 1)

The method of claim 1, wherein the JRC is bi-static JRC.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
transmitting, by the transmitter, the UW-OFDM symbols having a chirp sequence over a channel;
receiving the UW-OFDM symbols having a chirp sequence at a receiver; and
decoding the UW-OFDM symbols having a chirp sequence using a best linear unbiased estimator (BLUE) that is matched to the code generator matrix.

### Claim 9

A method for assembling unique word (UW)-orthogonal frequency division multiplexing (OFDM) data symbols for use in joint radar-sensing and communication (JRC), the method comprising:
providing OFDM frequency domain symbols to a code generator matrix of a transmitter to introduce redundancy into the OFDM frequency domain symbols;
modulating the OFDM frequency domain symbols having redundancy on a plurality of subcarriers using the IFFT block to generate OFDM time domain symbols; and
adding a predetermined chirp sequence in the OFDM frequency domain symbols to assemble UW-OFDM symbols having a chirp sequence, wherein the UW is the predetermined chirp sequence for joint radar-sensing and communication (JRC).

### Claim 10 (depends on 9)

The method of claim 9, wherein the OFDM time domain symbols comprise Nu zeroes and wherein Nu is an integer greater than one.

### Claim 11 (depends on 9)

The method of claim 9, further comprising:
transmitting, by the transmitter, the UW-OFDM symbols having a chirp sequence over a channel;
receiving the UW-OFDM symbols having a chirp sequence at a receiver; and
decoding the UW-OFDM symbols having a chirp sequence using a best linear unbiased estimator (BLUE) at the receiver that is matched to the code generator matrix.

### Claim 12

A transmitter for assembling unique word (UW)-orthogonal frequency division multiplexing (OFDM) data symbols for use in joint radar-sensing and communication (JRC), the transmitter comprising:
an N-point inverse fast Fourier transformation (IFFT) block to generate OFDM time domain symbols at an output; and
the transmitter to add a predetermined chirp sequence in the OFDM time domain symbols to assemble UW-OFDM symbols having a chirp sequence, wherein the UW is the predetermined chirp sequence for joint radar-sensing and communication (JRC).

### Claim 13 (depends on 12)

The transmitter of claim 12, wherein the OFDM time domain symbols comprise Nu zeroes and wherein Nu is an integer greater than one.

### Claim 14 (depends on 12)

The transmitter of claim 12, wherein the predetermined chirp sequence forms a tail of each of the OFDM time domain symbols.

### Claim 15 (depends on 12)

The transmitter of claim 12, wherein the N-point inverse fast Fourier transformation (IFFT) block further is further configured to:
provide OFDM frequency domain symbols to a code generator matrix to introduce redundancy into the OFDM frequency domain symbols; and
module the OFDM frequency domain symbols having redundancy on a plurality of subcarriers using the IFFT block to generate the OFDM time domain symbols.

### Claim 16 (depends on 12)

The transmitter of claim 12, wherein the redundancy introduced into the OFDM frequency domain by the code generator matrix is distributed over the plurality of subcarriers.

### Claim 17 (depends on 12)

The transmitter of claim 12, wherein the JRC is mono-static JRC.

### Claim 18 (depends on 12)

The transmitter of claim 12, wherein the JRC is bi-static JRC.

### Claim 19 (depends on 12)

The transmitter of claim 12, further comprising:
a receiver configured to receive the UW-OFDM symbols having a chirp sequence transmitted by the transmitter over a channel; and
the receiver configured to decode the UW-OFDM symbols having a chirp sequence using a best linear unbiased estimator (BLUE) that is matched to the code generator matrix.