METHOD FOR HARQ AND LINK ADAPTATION OF DEVICE TO DEVICE LINK IN DIRECT COMMUNICATION BETWEEN USER EQUIPMENTS AND RELAYING BY USER EQUIPMENT

• US 20120163252A1
• Filed: 12/27/2011
• Published: 06/28/2012
• Est. Priority Date: 12/27/2010
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: AHN, Jae Young, NOH, Tae Gyun, KO, Young Jo
• Granted Patent: US 9,014,062 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0019 in which mode-switching is based on a statistical approach
• CPC Class Codes: H04L 1/0027 Scheduling of signalling, e.g. occurrence thereof
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 2001/0097 Relays
• CPC Class Codes: H04L 5/1453 of modulation type
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/58 Format of the TPC bits

Abstract

Provided is a method of processing hybrid automatic repeat request (HARQ) and adaptive transmission of a device-to-device (D2D) link. In the method, an operation method of user equipment (UE) includes (a) receiving an initial transmission mode (TM) and transmission power for the D2D link from a base station, and performing data transmission through the D2D link, (b) determining, at the UE, a TM and transmission power of a succeeding subframe, or receiving a TM control value and a transmission power control value from counterpart UE of the D2D link and determining the TM and the transmission power of the succeeding subframe, and (c) performing the data transmission to the counterpart UE using the determined TM and transmission power. Here, (b) and (c) are repeated.

Claims

1. A method of processing hybrid automatic repeat request (HARQ) and adaptive transmission of a device-to-device (D2D) link when D2D link communication is performed in a time-division duplex (TDD) cellular communication system or a frequency-division duplex (FDD) cellular communication system using one of an uplink band and a downlink band, wherein an operation method of user equipment (UE) comprises:

(a) receiving an initial transmission mode (TM) and transmission power for the D2D link from a base station, and performing data transmission through the D2D link;

(b) determining, at the UE, a TM and transmission power of a succeeding subframe, or receiving a TM control value and a transmission power control value from counterpart UE of the D2D link and determining the TM and the transmission power of the succeeding subframe; and

(c) performing the data transmission to the counterpart UE using the determined TM and transmission power,

wherein (b) and (c) are repeated.

2. The method of claim 1, wherein the UE determines a modulation and coding scheme (MCS) level for the data transmission to the counterpart UE using channel reciprocity without receiving channel state information (CSI) from the counterpart UE.

3. The method of claim 1, wherein the TM control value and the transmission power control value are continuously received from the counterpart UE at given periods, or received only when the TM and the transmission power need to be changed.

4. The method of claim 1, wherein the TM control value and the transmission power control value are received through a different channel than received data, or included in the received data according to a piggyback scheme and received.

5. The method of claim 1, wherein (b) includes changing the TM and the transmission power when the counterpart UE repeatedly fails in receiving data transmitted in (c) a predetermined number of times or more during a predetermined time period.

6. The method of claim 1, wherein the operation method further comprises (d) requesting the base station to replace the D2D link with the counterpart UE with a cellular to link when the counterpart UE repeatedly fails in receiving data transmitted in (c) a predetermined number of times or more during a predetermined time period.

7. The method of claim 1, wherein, when the UE is legacy UE only capable of transmission through the uplink band and reception through the downlink band, the UE receives an acknowledgement (ACK) or a non-acknowledgement (NACK) of data transmitted in (c) from the counterpart UE via the base station.

8. The method of claim 1, wherein, when the counterpart UE is legacy UE only capable of transmission through the uplink band and reception through the downlink band, the UE receives an acknowledgement (ACK) or a non-acknowledgement (NACK) of data transmitted in (c) through an uplink control channel transmitted by the counterpart UE.

9. A method of processing hybrid automatic repeat request (HARQ) and adaptive transmission of a device-to-device (D2D) link when D2D link communication is performed using both an uplink band and a downlink band in a frequency-division duplex (FDD) cellular communication system, wherein an operation method of user equipment (UE) comprises:

(a) receiving an initial transmission mode (TM) and transmission power for the D2D link from a base station, and performing data transmission through the D2D link;

(b) determining, at the UE, a TM and transmission power of a succeeding subframe, or receiving a TM control value and a transmission power control value from counterpart UE of the D2D link and determining the TM and the transmission power of the succeeding subframe;

(c) receiving, at the UE, channel state information (CSI) from the counterpart UE, and determining a modulation and coding scheme (MCS) level of the succeeding subframe on the basis of the received CSI; and

(d) modulating and coding data according to the determined MCS level, and transmitting the modulated and coded data to the counterpart UE using the determined TM and transmission power,

wherein (b), (c) and (d) are repeated.

10. The method of claim 9, wherein the TM control value and the transmission power control value are continuously received from the counterpart UE at given periods, or received only when the TM and the transmission power need to be changed.

11. The method of claim 9, wherein the CSI is continuously received from the counterpart UE at given periods, or received only when the CSI changes from previously received CSI.

12. The method of claim 9, wherein at least one of the TM control value, the transmission power control value, and the CSI is received through a different channel than the received data, or included in the received data according to a piggyback scheme and received.

13. The method of claim 9, wherein (b) includes changing the TM and the transmission power when the counterpart UE repeatedly fails in receiving the data transmitted in (d) a predetermined number of times or more during a predetermined time period.

14. The method of claim 9, wherein (c) includes changing the MCS level when the counterpart UE repeatedly fails in receiving the data transmitted in (d) a predetermined number of times or more during a predetermined time period.

15. The method of claim 9, wherein the operation method further comprises (e) requesting the base station to replace the D2D link with the counterpart UE with a cellular link when the counterpart UE repeatedly fails in receiving the data transmitted in (d) a predetermined number of times or more during a predetermined time period.

16. The method of claim 9, wherein, when the UE is legacy UE only capable of transmission through the uplink band and reception through the downlink band, the UE receives an acknowledgement (ACK) or a non-acknowledgement (NACK) of the data transmitted in (d) from the counterpart UE via the base station.

17. The method of claim 9, wherein, when the counterpart UE is legacy UE only capable of transmission through the uplink band and reception through the downlink band, the UE receives an acknowledgement (ACK) or a non-acknowledgement (NACK) of the data transmitted in (d) through an uplink control channel transmitted by the counterpart UE.