METHOD AND APPARATUS FOR COMMUNICATIONS WITH CARRIER AGGREGATION

• US 20190320459A1
• Filed: 05/23/2019
• Published: 10/17/2019
• Est. Priority Date: 02/02/2016
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: SUN, Zhennian, JIANG, Chuangxin, GAO, Yukai, WANG, Gang
• Granted Patent: US 11,019,653 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/1273 of downlink data flows
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A method at a base station for performing data transmission to a user equipment in a communications system supporting carrier aggregation of at least one first carrier on which a short TTI is applied and at least one second carrier on which a long TTI is applied. The method transmits at least one DL scheduling grant corresponding to data transmission to the user equipment in a DL control region of at least one of a short TTI on a first carrier and a long TTI on a second carrier and performs DL data transmission towards the user equipment in a data transmission region of a short TTI on the first carrier and in the data transmission region of a long TTI on the second carrier as indicated by the at least one DL scheduling grant.

Claims

1. A method at a base station for performing data transmission to a user equipment in a communications system supporting carrier aggregation of at least one first carrier on which a short Transmission Time Interval, TTI is applied and at least one second carrier on which a long TTI is applied, the method comprising:

transmitting at least one downlink scheduling grant corresponding to data transmission to the user equipment in a downlink control region of at least one of a short TTI on a first carrier and a long TTI on a second carrier; and

performing downlink data transmission towards the user equipment in a data transmission region of a short TTI on the first carrier and in the data transmission region of a long TTI on the second carrier as indicated by the at least one downlink scheduling grant;

wherein said transmitting at least one downlink scheduling grant corresponding to data transmission to the user equipment comprises;

transmitting, in the downlink control region of a short TTI on the first carrier, a downlink scheduling grant corresponding to data transmission on the second carrier; and

the downlink data transmission on the second carrier is performed in a long TTI which is determined depending on a ratio of a length of the long TTI to a length of the short TTI and the short TTI where the corresponding downlink scheduling grant is transmitted;

or

transmitting, in the downlink control region of a long TTI on the second carrier, a downlink scheduling grant corresponding to data transmission on the first carrier; and

the downlink data transmission on the first carrier is performed in a short TTI which is determined depending on a ratio of a length of the short TTI to a length of the long TTI and the long TTI where the corresponding downlink scheduling grant is transmitted.

2. The method according to claim 1, wherein if transmitting, in the downlink control region of the short TTI on the first carrier, the downlink scheduling grant corresponding to data transmission on the second carrier, the method further comprises:

transmitting, in the downlink control region of a short TTI on the first carrier, a downlink scheduling grant corresponding to data transmission on the first carrier;

the downlink data transmission on the first carrier is performed in the short TTI where the corresponding downlink scheduling grant is transmitted or in a short TTI immediately following the short TTI where the corresponding downlink scheduling grant is transmitted; and

the downlink data transmission on the second carrier is performed in the long TTI whose index n_long and the index n_short of the short TTI where the corresponding downlink scheduling grant is transmitted have a relationship of n_long=n_short/2, wherein n_short is an even integer.

3. The method according to claim 1, wherein if transmitting, in the downlink control region of the long TTI on the second carrier, the downlink scheduling grant corresponding to data transmission on the first carrier, the method further comprises:

transmitting, in the downlink control region of a long TTI on the second carrier, a downlink scheduling grant corresponding to data transmission on the second carrier

the downlink data transmission on the second carrier is performed in the long TTI where the corresponding downlink scheduling grant is transmitted or in a long TTI immediately following the long TTI where the corresponding downlink scheduling grant is transmitted; and

the downlink data transmission on the first carrier is performed in the short TTI whose index n_short and the index n_long of the long TTI where the corresponding downlink scheduling grant is transmitted have a relationship of n_long=floor(n_short/2), wherein n_short is an integer;

or

the downlink data transmission on the first carrier is performed in the short TTI whose index n_short and the index n_long of the long TTI where the corresponding downlink scheduling grant is transmitted have a relationship of n_long=floor((n_short−

1)/2), wherein n_short is an integer.

4. A communication method at a base station for performing data transmission to a user equipment in a communication system, the method comprising:

transmitting at least one downlink scheduling grant corresponding to a downlink data transmission to the user equipment in a first, Transmission Time Interval, TTI; and

performing the downlink data transmission towards the user equipment in a second TTI;

wherein a length of the first TTI is different from the length of the second TTI and the second TTI is determined based on the first TTI and a length ratio between the first TTI and the second TTI.

5. A communication method at a user equipment in a communication system comprising:

receiving at least one downlink scheduling grant corresponding to a downlink data transmission in a first, Transmission Time Interval, TTI; and

receiving the downlink data transmission in a second TTI;

wherein a length of the first TTI is different from the length of the second TTI and the second TTI is determined based on the first TTI and a length ratio between the first TTI and the second TTI.

6. The method of claim 5, wherein the first TTI and the second TTI located in different carriers.

7. The method of claim 5, wherein one of the first TTI and second TTI is a short TTI and the other one is a long TTI, and a relationship between the first TTI and the second TTI is at least one of n_long=floor(n_short/2) and n_long=floor((n_short−

1)/2).