TERMINAL DEVICE AND METHOD FOR FACILITATING COMMUNICATION BETWEEN TERMINAL DEVICES

• US 20200136746A1
• Filed: 03/23/2018
• Published: 04/30/2020
• Est. Priority Date: 03/24/2017
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: LI, Shaohua, BLASCO SERRANO, Ricardo, FALLGREN, Mikael
• Granted Patent: US 11,296,815 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0016 involving special memory structures, e.g. look-up tables
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/1861 Physical mapping arrangements for ACK signaling see also H04L5/0053
• CPC Class Codes: H04L 1/1893 Physical mapping arrangements physical resource mapping in general H04L5/00
• CPC Class Codes: H04L 27/0012 arrangements for identifying the type of modulation
• CPC Class Codes: H04L 27/36 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04W 4/40 for vehicles, e.g. vehicle-to-pedestrians [V2P]
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A method in a first terminal device for facilitating direct communication with a second terminal device. The method comprises transmitting to the second terminal device a Modulation and Coding Scheme (MCS) index, based on which the second terminal device can obtain a modulation order and a Transport Block Size (TBS) in accordance with a first mapping or a second mapping between MCS indices on one hand and modulation orders and TBSs on the other. The MCS index is determined by the first terminal device by selectively applying the first or second mapping.

Claims

1. A method in a first terminal device for facilitating direct communication with a second terminal device, comprising:

transmitting to the second terminal device a Modulation and Coding Scheme (MCS) index, based on which the second terminal device can obtain a modulation order and a Transport Block Size (TBS) in accordance with a first mapping or a second mapping between MCS indices on one hand and modulation orders and TBSs on the other,

wherein the MCS index is determined by the first terminal device by selectively applying the first or second mapping.

2. The method of claim 1, wherein the second mapping supports a higher modulation order modulation orders supported by the first mapping.

3. The method claim 2, wherein the first and second mappings have an overlapped portion.

4. The method of claim 3, wherein the overlapped portion is associated with one or more of modulation orders supported by both the first and second mappings.

5. The method of claim 3, wherein the overlapped portion is associated with coding rates below a predefined threshold.

6. The method of claim 5, wherein, in a portion of the second mapping that does not overlap the first mapping, each TBS associated with the second mapping is scaled down with respect to a corresponding TBS associated with the first mapping by a factor dependent on a number of Resource Elements (REs) available for data transmission.

7. The method of claim 1, wherein the MCS index is determined by the first terminal device by applying the first mapping when retransmission is configured, or the second mapping when no retransmission is configured and a modulation order and a TBS obtained by applying the first mapping would result in a coding rate higher than a predefined threshold.

8. The method of claim 1, further comprising:

transmitting to the second terminal device an indicator indicating which of the first and second mappings is applied by the first terminal device.

9. The method of claim 1, wherein the second terminal device supports the first mapping only.

10. The method of claim 1, wherein the first and second terminal devices are communicating directly with each other on a sidelink for vehicular services.

11. A method in a first terminal device for facilitating direct communication with a second terminal device, comprising:

receiving from the second terminal device a Modulation and Coding Scheme (MCS) index determined by the second terminal device by applying a first mapping or a second mapping between MCS indices on one hand and modulation orders and Transport Block Sizes, (TBSs) on the other; and

obtaining, based on the MCS index, a modulation order and a TBS selectively in accordance with the first or second mapping.

12. The method of claim 11, wherein the second mapping supports a higher modulation order than modulation orders supported by the first mapping.

13. The method of claim 12, wherein the first and second mappings have an overlapped portion.

14. The method of claim 13, wherein the overlapped portion is associated with one or more of modulation orders supported by both the first and second mappings.

15. The method claim 13, wherein the overlapped portion is associated with coding rates below a predefined threshold.

16. The method of claim 15, wherein, in a portion of the second mapping that does not overlap the first mapping, each TBS associated with the second mapping is scaled down with respect to a corresponding TBS associated with the first mapping by a factor dependent on a number of Resource Elements (REs) available for data transmission.

17. The method of claim 11, wherein the modulation order and the TBS are obtained by the first terminal device in accordance with the first mapping when retransmission is configured, or with the second mapping when no retransmission is configured and a modulation order and a TBS obtained in accordance with the first mapping would result in a coding rate higher than a predefined threshold.

18. The method of claim 11, further comprising:

receiving from the second terminal device an indicator indicating which of the first and second mappings is applied by the second terminal device.

19. The method of claim 11, wherein the second terminal device supports the first mapping only.

20. (canceled)

21. A first terminal device in direct communication with a second terminal device, the first terminal device comprising:

a transceiver;

a processor coupled to the transceiver; and

a memory comprising instructions which, when executed by the processor, cause the first terminal device to perform operations to;

transmit to the second terminal device a Modulation and Coding Scheme (MCS) index, based on which the second terminal device can obtain a modulation order and a Transport Block Size (TBS) in accordance with a first mapping or a second mapping between MCS indices on one hand and modulation orders and TBSs on the other,

wherein the MCS index is determined by the first terminal device by selectively applying the first or second mapping.

22. (canceled)