# US 12,015,509 B2 · Method for transmitting DMRS in wireless communication system supporting NB-IoT and apparatus therefor

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- Number: US 12,015,509 B2
- Document ID: US12015509B2
- Status: Granted
- Kind: B2
- Application number: 17/844,503
- Filed: 2022-06-20
- Published: 2022-10-13
- Granted: 2024-06-18
- Earliest claimed: 2016-02-02
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Seunggye Hwang; Hyunsoo Ko; Yunjung Yi; Bonghoe Kim; Kijun Kim
- Web page: https://patentgrep.com/patent/US12015509B2

## CPC

- H04L 27/0008: {arrangements for allowing a transmitter or receiver to use more than one type of modulation (negotiating modulation type for two-way transmission paths H04L5/1453)}
- H04L 1/0061: {Error detection codes}
- H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT}
- H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals}
- H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal}
- H04L 5/0083: {symbol-by-symbol}
- H04L 27/22: Demodulator circuits; Receiver circuits
- H04L 27/2607: {Cyclic extensions}
- H04L 27/2613: {Structure of the reference signals}
- H04L 27/2614: {Peak power aspects}
- H04L 27/3444: {by applying a certain rotation to regular constellations}
- H04W 4/70: Services for machine-to-machine communication [M2M] or machine type communication [MTC]
- H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
- H04W 72/0446: Resources in time domain, e.g. slots or frames
- H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA
- H04W 92/10: between terminal device and access point, i.e. wireless air interface
- H04L 1/1664: {the supervisory signal being transmitted together with payload signals; piggybacking}
- H04L 5/0062: {Avoidance of ingress interference, e.g. ham radio channels}
- Y02D 30/70: in wireless communication networks
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

The present specification relates to a method for transmitting, by a terminal, a demodulation reference signal (DMRS) in a wireless communication system supporting narrow-band (NB)-Internet of things (IOT), the method comprising: generating, for single tone transmission, a reference signal sequence to be used for demodulation; mapping the reference signal sequence to a plurality of symbols; and transmitting, in the plurality of symbols, the demodulation reference signal to a base station by using a single tone, wherein phase rotation is applied to each of the plurality of symbols.

## Claims

### Claim 1

A method of transmitting, by a user equipment, a narrow band (NB) physical uplink channel in a wireless communication system supporting Narrowband-Internet of Things (NB-IoT), the method comprising:
determining, based on a number of at least one subcarrier in resource unit for the NB physical uplink channel being ‘1’, a binary phase shift keying (BPSK) or a quadrature phase shift keying (QPSK) as modulation scheme for the NB physical uplink channel;
determining, based on the modulation scheme for the NB physical uplink channel, a phase rotation for each of one or more symbols; and
transmitting, to a base station, the NB physical uplink channel on the one or more symbols based on the phase rotation.

### Claim 2 (depends on 1)

The method of claim 1, wherein the phase rotation is determined based on a first value and a second value,
wherein the first value is determined based on the modulation scheme, and
wherein the second value is a value of a modulo operation of 2 for a symbol index, the symbol index indicating a symbol within a specific time unit.

### Claim 3 (depends on 2)

The method of claim 2, wherein the first value is π/2 or π/4.

### Claim 4 (depends on 1)

The method of claim 1, further comprising: transmitting, to the base station, a demodulation reference signal (DMRS).

### Claim 5 (depends on 4)

The method of claim 4, wherein a DMRS sequence is generated based on a pseudo-random sequence.

### Claim 6 (depends on 4)

The method of claim 4, wherein the transmission of the DMRS is performed in an inband mode of the NB-IoT system.

### Claim 7 (depends on 1)

The method of claim 1, wherein an orthogonal cover code (OCC) is applied to the one or more symbols.

### Claim 8 (depends on 1)

The method of claim 1, wherein the phase rotation is applied to each of the one or more symbols to which the NB physical uplink channel is mapped.

### Claim 9 (depends on 8)

The method of claim 8, wherein an initial phase value of the phase rotation is applied at a start of each specific unit.

### Claim 10 (depends on 9)

The method of claim 9, wherein the specific unit is a slot, subframe or radio frame.

### Claim 11 (depends on 9)

The method of claim 9, wherein the initial phase value is set based on at least one of a cell identifier (ID) or the specific unit.

### Claim 12

A user equipment configured to transmit a narrow band (NB) physical uplink channel in a wireless communication system supporting Narrowband-Internet of Things (NB-IoT), the user equipment comprising:
at least one transceiver;
at least one processor; and
at least one memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:
determining, based on a number of at least one subcarrier in resource unit for the NB physical uplink channel being ‘1’, a binary phase shift keying (BPSK) or a quadrature phase shift keying (QPSK) as modulation scheme for the NB physical uplink channel;
determining, based on the modulation scheme for the NB physical uplink channel, a phase rotation for each of one or more symbols; and
transmitting, to a base station, the NB physical uplink channel on the one or more symbols based on the phase rotation.