Receiver method, receiver, transmission method, transmitter, transmitter-receiver system, and communication apparatus

• US 10,666,486 B2
• Filed: 03/29/2019
• Issued: 05/26/2020
• Est. Priority Date: 01/22/2018
• Status: Active Grant

• Current Assignee: Radius Co., Ltd.
• Original Assignee: Radius Co., Ltd.
• Inventors: Kohda, Tohru
• Primary Examiner(s): Lam, Kenneth T
• Application Number:
  US16/369,053
• Publication Number:
  US 20190229972A1
• Time in Patent Office: 424 Days
• CPC Class Codes: H04B 1/70757 with increased resolution, i.e. higher than half a chip H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2639 Modulators using other transforms, e.g. discrete cosine transforms, Orthogonal Time Frequency and Space [OTFS] or hermetic transforms
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2662 Symbol synchronisation
• CPC Class Codes: H04L 27/2669 characterised by the domain of operation
• CPC Class Codes: H04L 27/2679 Decision-aided
• CPC Class Codes: H04L 27/32 Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26

Abstract

In accordance with an embodiment of the present invention, a method for receiving a signal, comprising the estimation step for estimating time and frequency shifts that are embedded in the received signal, to cancel-out shifts, wherein the method refers to the non-commutative shift parameter space of co-dimension 2.

Claims

1. A method for receiving a signal, comprising

receiving a signal at a receiver apparatus, and

performing an estimation step at the receiver apparatus for estimating a time shift and a frequency shift that are embedded in the signal, wherein the estimation step refers to a non-commutative shift parameter space of co-dimension 2, and in the estimation step, the time shift and the frequency shift that are embedded in the signal are estimated with an operator including a half shift that is a shift symmetrical in time and frequency.

2. The method recited in claim 1, wherein the non-commutative shift parameter space of co-dimension 2 is a space obtained by 3-dimensionalizing a plane, which is defined by a first axis indicative of time and a second axis indicative of frequency, by attaching, to the plane, a third axis indicative of time-frequency shifts.

3. The method recited in claim 1, wherein the estimation step estimates the time shift and the frequency shifts that are embedded in the signal, with use of a time-frequency shift operator(TFSO) of type 1 representing an estimated time shift, frequency shift, and a phase term due to a half shift of the estimated time shift

[MFC1]

,

a TFSO of type 2 representing time shift, an estimated frequency shift, and a phase term due to a half shift of the estimated frequency shift

[MFC2]

,

a TFSO of type 3 representing an observable time shift to be estimated, an observable frequency shift to be estimated, and a phase term due to a half shift of the time shift to be estimated

[MFC3]

_kd,lD^d

or a frequency dual of the TFSO of type 3

[MFC4]

_lD,−

k_d^f,d,

and a TFSO of type 4 representing the estimated time shift, the estimated frequency shift, and the phase term due to the half shift of the estimated time shift

[MFC5]

_{{circumflex over (k)}d,{circumflex over (l)}D}^d

or a frequency dual of the TFSO of type 4

[MFC6]

<sub>{circumflex over (l)}D,−

{circumflex over (k)}d</sub>^f,d,

wherein

{circumflex over (k)}_d denotes an integer-valued estimate of k_d,

k_d denotes time delay/shift,

k is an integer given by

k=j₀+j′

, j=[k/₀], j′

={k/₀},

where j and j′

are integers, and ₀ denotes multiplex count,

l_μ

′

is a maximum likelihood estimate (MLE) of l_μ

for a given {circumflex over (k)}_d,

l_μ

denotes an integer-valued control parameter for estimating l_D,

{circumflex over (l)}_D is an integer-valued maximum likely estimate of l_D,

k_θ

is a maximum likelihood estimate of k_d for a given {circumflex over (l)}_D, and

l_D denotes frequency delay/shift.

4. The method recited in claim 3, wherein the estimation step estimates the time shift and the frequency shift that are embedded in the signal, with use of a time-domain-cross-correlation function(TD-CCF) of type 1, represented in terms of the TFSOs of type 1, of type 3, and of type 4, and a frequency-domain-cross-correlation function(FD-CCF) of type 2, represented in terms of the TFSOs of type 2, of type 3, and of type 4.

5. The method recited claim 4, wherein the TD-CCF of type 1 and the FD-CCF of type 2 contain a phase distortion(PD) due to a non-commutative shift operation between modulation and demodulation by a carrier f_c and a time shift t_d

[MFC7]

e^j2π

t^dfc

or a discretized version of the PD

[MFC8]

W^kdlc,

and a PD due to the phase term e^iκ

of the attenuation factor Ae^iκ

.

6. The method recited in claim 4, wherein the estimation step includes two alternative updating steps:

(1) updating the estimated frequency shift with reference to the TD-CCF of type 1 and (2) updating the estimated time shift with reference to the FD-CCF of type 2.

7. The method recited in claim 1, wherein the estimation step estimates the time shift and the frequency shift that are embedded in the signal, with use of maximum-likelihood estimate(MLE)s of frequency shift for detecting N′

time-domain(TD)-templates and MLEs of time shift for detecting N frequency-domain(FD)-templates.

8. A receiving apparatus for receiving a signal, comprising

a receiving circuitry for receiving a signal, and

an estimation circuitry for estimating a time shift and a frequency shift that are embedded in the signal, with reference to a non-commutative shift parameter space of co-dimension 2, wherein the estimation circuitry estimates the time shift and the frequency shift that are embedded in the signal with use of an operator including a half shift that is a shift symmetrical in time and frequency.

9. A method for transmitting a signal, comprising

performing shift step at a transmitter apparatus for time-frequency shifting the signal to be transmitted, with reference to a non-commutative shift parameter space of co-dimension 2, and in the shift step, a time and a frequency of the signal to be transmitted are shifted by a half shift that is a shift symmetrical in time and frequency, and

transmitting the signal at the transmitter apparatus.

10. The method recited in claim 9, wherein the shift step generates the signal to be transmitted by phase-shift-keying(PSK)-modulating a chip pulse wave in the time domain(TD) by the TD-phase code(PC) of period N and PSK-modulating the TD-PSK modulated TD-pulse wave by the FD-PC of period N′

to generate a multicarrier version of the TD-PSK modulated TD-pulse wave.

11. A transmitter apparatus for transmitting a signal, comprising

a time-frequency shift circuitry for time-frequency shifting the signal to be transmitted, with reference to a non-commutative shift parameter space of co-dimension 2, wherein the shift circuitry shifts a time and a frequency of the signal to be transmitted with use of a half shift that is a shift symmetrical in time and frequency, and

a transmitting circuitry for transmitting the signal.

12. A transmitter-receiver system, comprising:

a transmitter apparatus; and

a receiver apparatus,

the transmitter apparatus including a time-frequency shift part for time-frequency shifting a signal to be transmitted, with reference to a non-commutative shift parameter space of co-dimension 2,

the receiver apparatus including an estimation part for estimating a time shift and a frequency shift that are embedded in the signal to be transmitted, with reference to the non-commutative shift parameter space of co-dimension 2.

13. A method for receiving a signal, comprising

receiving a signal at a receiver apparatus, and

performing an estimation step at the receiver apparatus for estimating a time shift and a frequency shift that are embedded in the signal, wherein the estimation step refers to a non-commutative shift parameter space of co-dimension 2,

wherein the non-commutative shift parameter space of co-dimension 2 is a space obtained by 3-dimensionalizing a plane, which is defined by a first axis indicative of time and a second axis indicative of frequency, by attaching, to the plane, a third axis indicative of time-frequency shifts.

14. A method for receiving a signal, comprising

receiving a signal at a receiver apparatus, and

performing an estimation step at the receiver apparatus for estimating a time shift and a frequency shift that are embedded in the signal, wherein the estimation step refers to a non-commutative shift parameter space of co-dimension 2,

wherein the estimation step estimates the time shift and the frequency shifts that are embedded in the signal, with use of a time-frequency shift operator(TFSO) of type 1 representing an estimated time shift, frequency shift, and a phase term due to a half shift of the estimated time shift

_{{circumflex over (k)}d,lμ}

,

a TFSO of type 2 representing time shift, an estimated frequency shift, and a phase term due to a half shift of the estimated frequency shift

[MFC2]

<sub>{circumflex over (l)}D,−

kσ

∝</sub>

^f,d,

a TFSO of type 3 representing an observable time shift to be estimated, an observable frequency shift to be estimated, and a phase term due to a half shift of the time shift to be estimated

[MFC3]

_kd,lD^d

or a frequency dual of the TFSO of type 3

[MFC4]

<sub>lD,−

kd</sub>^f,d,

and a TFSO of type 4 representing the estimated time shift, the estimated frequency shift, and the phase term due to the half shift of the estimated time shift

[MFC5]

_{{circumflex over (k)}d,{circumflex over (l)}D}^d

or a frequency dual of the TFSO of type 4

[MFC6]

<sub>{circumflex over (l)}D,−

{circumflex over (k)}d</sub>^f,d,

wherein

{circumflex over (k)}_d denotes an integer-valued estimate of k_d,

k_d denotes time delay/shift,

k is an integer given by

k=j₀+j′

, j=[k/₀], j′

={k/₀},

where j and j′

are integers, and ₀ denotes multiplex count,

l_μ

′

is a maximum likelihood estimate (MLE) of l_μ

for a given {circumflex over (k)}_d,

l_μ

denotes an integer-valued control parameter for estimating l_D,

{circumflex over (l)}_D is an integer-valued maximum likely estimate of l_D,

k<sub>σ

′</sub>

is a maximum likelihood estimate of k_d for a given {circumflex over (l)}_D, and

l_D denotes frequency delay/shift.

15. A method for receiving a signal, comprising

receiving a signal at a receiver apparatus, and

performing an estimation step at the receiver apparatus for estimating a time shift and a frequency shift that are embedded in the signal, wherein the estimation step refers to a non-commutative shift parameter space of co-dimension 2,

wherein the estimation step estimates the time shift and the frequency shift that are embedded in the signal, with use of maximum-likelihood estimate(MLE)s of frequency shift for detecting N′

time-domain(TD)-templates and MLEs of time shift for detecting N frequency-domain(FD)-templates.

16. A method for transmitting a signal, comprising

performing shift step at a transmitter apparatus for time-frequency shifting the signal to be transmitted, with reference to a non-commutative shift parameter space of co-dimension 2,

wherein the shift step generates the signal to be transmitted by phase-shift-keying(PSK)-modulating a chip pulse wave in the time domain(TD) by the TD-phase code(PC) of period N and PSK-modulating the TD-PSK modulated TD-pulse wave by the FD-PC of period N′

to generate a multicarrier version of the TD-PSK modulated TD-pulse wave, and

transmitting the signal at a transmitter apparatus.