# US 11,310,777 B2 · Method and apparatus for communication based on short transmission time intervals in wireless communication system

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- Number: US 11,310,777 B2
- Document ID: US11310777B2
- Status: Granted
- Kind: B2
- Application number: 16/234,103
- Filed: 2018-12-27
- Published: 2019-05-02
- Granted: 2022-04-19
- Earliest claimed: 2018-12-27
- Assignees: NEC Corporation
- Applicants: NEC Corporation
- Inventors: Yulai Gao; Chuangxin Jiang; Gang Wang
- Web page: https://patentgrep.com/patent/US11310777B2

## CPC

- H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network
- H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal}
- H04L 5/0055: {Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861)}
- H04L 5/0094: {Indication of how sub-channels of the path are allocated}
- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04L 1/1671: {the supervisory signal being transmitted together with control information}
- H04L 1/1854: {Scheduling and prioritising arrangements}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Embodiments of the present disclosure relate to the communication processes in a wireless communication system based on short TTIs. According to one embodiment of the present disclosure, there provide a method for communication by a base station. The method comprise: receiving, from a user equipment, an uplink demodulation reference signal, DMRS, in an uplink transmission time interval, TTI, of an uplink subframe, which supports two or more uplink TTIs. At least one uplink TTI supported by the uplink subframe is configured to only transmit uplink control information and/or uplink data without any uplink DMRS. In the other aspects of the present disclosure, there also provides methods for communication by a user equipment and corresponding apparatuses.

## Claims

### Claim 1

A method of a user equipment (UE), the method comprising:
receiving first information from a base station in a higher layer signaling;
receiving second information from the base station in a DCI (Downlink Control Information) format;
determining, based on the first information, whether to transmit at least one second DMRS(s) (Demodulation Reference Signal(s)) for PUSCH (Physical Uplink Shared Channel) in addition to a first DMRS for PUSCH,
wherein the first DMRS is transmitted regardless of the first information and the second information, and
wherein the first information provides a group of more than one candidates of at least one symbol(s) at second position(s) within a scheduling unit in a case where the at least one second DMRS(s) is to be transmitted;
in the case where the at least one second DMRS(s) is to be transmitted, transmitting the first DMRS and the at least one second DMRS(s), the first DMRS being transmitted at a first position within the scheduling unit and the at least one second DMRS(s) being transmitted at the second position(s) within the scheduling unit,
wherein the second position(s) is determined, based on the second information, from among the more than one candidates; and
in a case where the at least one second DMRS(s) is not to be transmitted, transmitting the first DMRS without the at least one second DMRS(s) being transmitted within the scheduling unit.

### Claim 2 (depends on 1)

The method according to claim 1, wherein a number of the at least one symbol(s) at the second position(s) is variable based on the second information.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the DCI format is configured to be used for scheduling the PUSCH.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the PUSCH is not transmitted at the first position and the at least one symbol(s) at the second position(s).

### Claim 5 (depends on 4)

The method according to claim 4, wherein the first DMRS or the at least one second DMRS(s) is transmitted prior to resources for the PUSCH.

### Claim 6 (depends on 1)

The method according to claim 1, wherein, at the first position or the second position(s), the first DMRS or the at least one second DMRS(s) is transmitted using one resource element from among every two consecutive resource elements in frequency domain, and
wherein remaining resource elements not used for the first DMRS or the at least one second DMRS(s) at the first position or the second position(s) are used for transmission of the PUSCH.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the scheduling unit is configured for assigning the PUSCH.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the first position is prior to all of the second position(s) within the scheduling unit in time domain.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the first position is a fourth symbol of the scheduling unit.

### Claim 10 (depends on 1)

The method according to claim 1, the method further comprising:
determining whether the second position(s) comprises more symbol(s) than the first position, based on the first information.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the first position corresponds to one symbol, and
wherein no DMRS for PUSCH other than the first DMRS or the at least one second DMRS(s) is transmitted within the scheduling unit.

### Claim 12

The method of claiml, wherein the second information indicates a number of symbols for the first DMRS or the at least one second DMRS(s).

### Claim 13

A user equipment (UE) comprising:
a transceiver configured to:
receive first information from a base station in a higher layer signaling; and
receive second information from the base station in a DCI (Downlink Control Information) format; and
a controller configured to determine, based on the first information, whether to transmit at least one second DMRS(s) (Demodulation Reference Signal(s)) for PUSCH (Physical Uplink Shared Channel) in addition to a first DMRS for PUSCH,
wherein the first DMRS is transmitted regardless of the first information and the second information, and
wherein the first information provides a group of more than one candidates of at least one symbol(s) at second position(s) within a scheduling unit in a case where the at least one second DMRS(s) is to be transmitted,
wherein the controller is configured to, in the case where the at least one second DMRS(s) is to be transmitted, control the transceiver to transmit the first DMRS and the at least one second DMRS(s), the first DMRS being transmitted at a first position within the scheduling unit and the at least one second DMRS(s) being transmitted at the second position(s) within the scheduling unit,
wherein the second position(s) is determined, based on the second information, from among the more than one candidates, and
wherein the controller is configured to, in a case where the at least one second DMRS(s) is not to be transmitted, control the transceiver to transmit the first DMRS without the at least one second DMRS(s) being transmitted within the scheduling unit.

### Claim 14 (depends on 13)

The UE according to claim 13, wherein a number of the at least one symbol(s) at the second position(s) is variable based on the second information.

### Claim 15 (depends on 13)

The UE according to claim 13, wherein the DCI format is configured to be used for scheduling the PUSCH.

### Claim 16 (depends on 13)

The UE according to claim 13, wherein the PUSCH is not transmitted at the first position and the at least one symbol(s) at the second position(s).

### Claim 17 (depends on 16)

The UE according to claim 16, wherein the first DMRS or the at least one second DMRS(s) is transmitted prior to resources for the PUSCH.

### Claim 18 (depends on 13)

The UE according to claim 13, wherein, at the first position or the second position(s), the first DMRS or the at least one second DMRS(s) is transmitted using one resource element from among every two resource elements in frequency domain, and
wherein the UE is configured such that remaining resource elements not used for the first DMRS or the at least one second DMRS(s) at the first position or the second position(s) are used for transmission of the PUSCH.

### Claim 19 (depends on 13)

The UE according to claim 13, wherein the scheduling unit is configured for assigning the PUSCH.

### Claim 20 (depends on 13)

The UE according to claim 13, wherein the first position is prior to all of the second position(s) within the scheduling unit in time domain.

### Claim 21 (depends on 13)

The UE according to claim 13, wherein the first position is a fourth symbol of the scheduling unit.

### Claim 22 (depends on 13)

The UE according to claim 13, wherein the controller is configured to determine whether the second position(s) comprises more symbol(s) than the first position, based on the first information.

### Claim 23

A method of a base station, the method comprising:
transmitting first information to a User Equipment (UE) in a higher layer signaling;
transmitting second information to the UE in a DCI (Downlink Control Information) format;
wherein, whether at least one second DMRS(s) (Demodulation Reference Signal(s)) for PUSCH (Physical Uplink Shared Channel), in addition to a first DMRS for PUSCH, is to be received corresponds to the first information,
wherein the first DMRS is to be received regardless of the first information and the second information, and
wherein the first information provides a group of more than one candidates of at least one symbol(s) at second position(s) within a scheduling unit in a case where the at least one second DMRS(s) is to be received;
in the case where the at least one second DMRS(s) is to be received, receiving the first DMRS and the at least one second DMRS(s), the first DMRS being received at a first position within the scheduling unit and the at least one second DMRS(s) being received at the second position(s) within the scheduling unit,
wherein the second position(s) is determined, based on the second information, from among the more than one candidates; and
in a case where the at least one second DMRS(s) is not to be received, receiving the first DMRS without the at least one second DMRS(s) being received within the scheduling unit.

### Claim 24 (depends on 23)

The method according to claim 23, wherein the first position corresponds to one symbol, and
wherein no DMRS for PUSCH other than the first DMRS or the at least one second DMRS(s) is received within the scheduling unit.