# US 11,121,901 B2 · Symbols incorporation scheme for DFT-S-OFDM

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- Number: US 11,121,901 B2
- Document ID: US11121901B2
- Status: Granted
- Kind: B2
- Application number: 17/056,843
- Filed: 2019-06-24
- Published: 2021-07-08
- Granted: 2021-09-14
- Earliest claimed: 2018-07-26
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Cristina Ciochina
- Web page: https://patentgrep.com/patent/US11121901B2

## CPC

- H04L 27/26134: {Pilot insertion in the transmitter chain, e.g. pilot overlapping with data, insertion in time or frequency domain}
- H04L 27/2614: {Peak power aspects}
- H04L 27/262: {Reduction thereof by selection of pilot symbols}
- H04L 27/2636: {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]}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

The invention relates to a method for transmitting a group of Q symbols (A0; . . . ; AQ−1) in a DFTsOFDM radio signal, said radio signal being provided by applying a M size DFT and a N-size IDFT to a block of symbols X=(X0, . . . XM−1), said method comprising: —determining Q positions ni in the block of symbols, such as (I); —transmitting the Q symbols through the radio signal, such as for each i, samples of the symbol ai in the radio signal are equal to a result of the application of a DFTsOFDM scheme to a block of M symbols with values of symbols Xni+mL, being ej2πk(ni+mL)/MAi with k integer such as 0≤k<K, with m integer such as 0≤m<K.

## Claims

### Claim 1

A method for transmitting at least a group of Q symbols (A0; . . . ; AQ−1) in a radio signal to be transmitted over a wireless communication system, said radio signal being intended to be emitted by an emitter comprising at least one transmit antenna configured for transmitting on at least a number M, of different frequencies, M being equal to L·K with L and K strictly positive integer and Q being a strictly positive integer strictly smaller than L, said radio signal being provided by:
applying a M size DFT to a block of symbols X=(X0, . . . XM−1), and obtaining for each kth frequency, with k=0 to M−1, a complex symbol Sk in the frequency domain;
obtaining, at an output of an IDFT module corresponding to a transmit antenna a signal representing, in the frequency domain, complex symbols respectively function of Sk for each kth frequency with k=0 to M−1;
emitting the radio signal corresponding to the signal;
said method comprising:
determining Q positions ni in the block of symbols, such as {ni|i∈0;Q−1, 0≤ni<L, ∀i, i′∈0;Q−12, i<i′ni<ni′};
transmitting the Q symbols through the radio signal, such as for each i, samples of the symbol ai in the radio signal are equal to a result outputted by the IDFT module, of the application of the DFT to a block of M symbols with values of symbols Xni+mL, in the positions ni+mL, being respectively ej2πk(ni+mL)/MAi, with k integer such as 0≤k<K, with m integer such as 0≤m<K, and j the imaginary number.

### Claim 2 (depends on 1)

The method according to claim 1, wherein transmitting the Q symbols is done by setting the symbol Xni+mL to the value ej2πk(ni+mL)/MAi, for each i and m.

### Claim 3 (depends on 1)

The method according to claim 1, said method further comprising setting the values of the symbols Xni+mL to 0, with (i; m)∈0;Q−1×0;K−1, before applying the DFT and obtaining a subsequent signal at the output of the IDFT module;
and wherein for each i and m, transmitting the Q symbols is done by adding the samples in said subsequent signal at the output of the IDFT module.

### Claim 4 (depends on 1)

The method according to claim 1, said method further comprising setting the values of the symbols Xni+mL to 0, with (i; m)∈0;Q−1×0;K−1, before applying the DFT and obtaining a subsequent signal at the output of the DFT module;
and wherein for each i and m, transmitting the Q symbols is done by adding the samples in said subsequent signal at the output of the DFT module.

### Claim 5 (depends on 1)

The method according to claim 1, wherein at least K′ groups of Qp symbols (A0p; . . . ; AQp−1p) are transmitted in the radio signal, with the Qp being strictly positive integers and ΣQp≤L and K′≤K, said method comprising for each p:
determining a kp integer and Qp positions of nip in the block of symbols such as
{
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transmitting the Qp symbols through the radio signal, such as for each i, samples of the symbol Aip in the radio signal are equal to a result outputted by the IDFT module, of the application of the DFT to a block of M symbols with values of symbols Xnip+mL, in the positions nip+mL, are respectively ej2πkp(nip+mL)/MAip, with m∈0;K−1.

### Claim 6 (depends on 5)

The method according to claim 5, wherein if ΣQp≠L, ∀n≠nip, with (i; p)∈0;Q−1×1;K′, the values of the symbols Xn is set to 0 before applying the DFT.

### Claim 7 (depends on 5)

The method according to claim 5, wherein K′<K.

### Claim 8 (depends on 5)

The method according to claim 5, wherein K′=K.

### Claim 9 (depends on 5)

The method according to claim 5, wherein for at least one p, L=Qpc, with c positive integer, and
{
n
i
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∈
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=
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.

### Claim 10 (depends on 5)

The method according to claim 5, wherein for at least one p, {nip|nQp−1p−n0p=Qp−1}.

### Claim 11 (depends on 1)

Computer program product comprising code instructions to perform the method according to claim 1, when said instructions are run by a processor.

### Claim 12

A device for transmitting at least a group of Q symbols (A0; . . . ; AQ−1) in a radio signal to be transmitted over a wireless communication system, said radio signal being intended to be emitted by an emitter comprising at least one transmit antenna configured for transmitting on at least a number M, of different frequencies, M being equal to L·K with L and K strictly positive integer and Q being a strictly positive integer strictly smaller than L, said radio signal being provided by:
applying a M size DFT to a block of symbols X=(X0, . . . XM−1), and obtaining for each kth frequency, with k=0 to M−1, a complex symbol Sk in the frequency domain;
obtaining, at an output of an IDFT module corresponding to a transmit antenna a signal representing, in the frequency domain, complex symbols respectively function of Sk for each kth frequency with k=0 to M−1;
emitting the radio signal corresponding to the signal;
said device being configured to:
determine Q positions ni, in the block of symbols, such as {ni|i∈0;Q−1, 0≤ni<L, ∀i, i′∈0;Q−12, i<i′ni<ni′};
transmitting the Q symbols through the radio signal, such as for each i, samples of the symbol ai in the radio signal are equal to a result outputted by the IDFT module, of the application of the DFT to a block of M symbols with values of symbols Xni+mL, in the positions ni+mL, being respectively ej2πk(ni+mL)/MAi, with k integer such as 0≤k<K, with m integer such as 0≤m<K, and j the imaginary number.