Systems and methods for nr v2x csi feedback without dedicated reference signals

Patent metadata

Field	Value
Publication number	US-2021367717-A1
Application number	US-201917277108-A
Country	US
Kind code	A1
Filing date	Sep 26, 2019
Priority date	Sep 28, 2018
Publication date	Nov 25, 2021
Grant date	—

Abstract

A user equipment (UE) configured for multi-antenna communication estimates at least one of a rank indicator and a channel quality indicator for device to device (D2D) based on communication data associated with a plurality of packets communicated using D2D communication and without using a dedicated reference signal for D2D communication. The UE may be configured as at least one of a transmitter (Tx) and a receiver (Rx) for vehicle-to-everything (V2X) communication through a sidelink channel.

First claim

1 . An apparatus for a user equipment (UE) configured for multi-antenna communication, the apparatus comprising:
a memory interface to send or receive, to or from a memory device, communication data associated with a plurality of packets communicated using device to device (D2D) communication; and a processor to:
estimate, based on the communication data and without using a dedicated reference signal for the D2D communication, at least one of a rank indicator and a channel quality indicator for the D2D communication; and
encode a feedback message to one or more transmitters participating in the D2D communication, the feedback message indicating at least one of the rank indicator and the channel quality indicator.

2 . The apparatus of claim 1 , wherein the UE is configured as at least one of a transmitter (Tx) and a receiver (Rx) for vehicle-to-everything (V2X) communication.

3 . The apparatus of claim 1 , wherein the communication data comprises hybrid automatic repeat request (HARD) information include acknowledgment (ACK) responses and negative acknowledgment (NACK) responses associated with the plurality of packets.

4 . The apparatus of claim 3 , wherein the processor is further configured to:
for a selected modulation-code scheme, monitor the ACK responses and the NACK responses; if the NACK responses increase over a period of time, adjust the modulation-coding scheme to reduce a number of bits per symbol; if the NACK responses decrease or are below a threshold number over the period of time, adjust the modulation-coding scheme to increase the number of bits per symbol; and encode the feedback message to include an indication of an adjustment of the modulation-coding scheme.

5 . The apparatus of claim 4 , wherein to adjust the modulation-coding scheme comprises only adjusting the modulation-coding scheme every X number of received ACK/NACK responses.

6 . The apparatus of claim 1 , wherein the communication data comprises demodulation information associated with demodulation of the plurality of packets received at the UE using the D2D communication over a period of time.

7 . The apparatus of claim 6 , wherein the demodulation information comprises a demodulation reference signal (DMRS).

8 . The apparatus of claim 7 , wherein the processor is further configured to:
determine an estimated channel based on the DMRS to demodulate the plurality of packets; and calculate the channel quality indicator based on long term statistics of the estimated channel.

9 . The apparatus of claim 8 , wherein the processor is further configured to:
determine, based on the DMRS, an interference measurement per sub-channel; and determine the channel quality indicator by averaging or weighting both the estimated channel and the interference measurement over at least one of the period of time and a bandwidth used for transmission.

10 . The apparatus of claim 8 , wherein the processor is further configured to estimate the rank indicator based on the long term statistics of the estimated channel.

11 . The apparatus of claim 10 , wherein the processor is further configured to:
if channel coefficients received at different receive antennas of the UE corresponding to a same subcarrier and orthogonal frequency division multiplexing (OFDM) symbol are highly correlated, configure the UE to use a single spatial layer for the D2D communication; and if the channel coefficients are weakly correlated, configure the UE to use multiple spatial layers for the D2D communication.

12 . The apparatus of claim 1 , wherein the processor is further configured to:
exchange codebook information with one or more transmitters or receivers in communication with the UE using the D2D communication, the codebook information indicating a cycling of precoders used for the plurality of packets; estimate, based on the cycling of precoders, a multiple input multiple output (MIMO) channel; and determine the rank indicator based on the MIMO channel.

13 . A non-transitory computer-readable storage medium, the computer-readable storage medium including instructions that when executed by a baseband processor of a vehicle-to-everything (V2X) device, cause the baseband processor to:
estimate, based on communication data associated with a plurality of packets communicated using device to device (D2D) communication and without using a dedicated reference signal for the D2D communication, at least one of a rank indicator and a channel quality indicator for the D2D communication; and encode a feedback message to one or more transmitters participating in communication using the D2D communication, the feedback message indicating at least one of the rank indicator and the channel quality indicator.

14 . The computer-readable storage medium of claim 13 , wherein the communication data comprises hybrid automatic repeat request (HARD) information include acknowledgment (ACK) responses and negative acknowledgment (NACK) responses associated with the plurality of packets communicated.

15 . The computer-readable storage medium of claim 14 , wherein the instructions further configure the baseband processor to:
for a selected modulation-code scheme, monitor the ACK responses and the NACK responses; if the NACK responses increase over a period of time, adjust the modulation-coding scheme to reduce a number of bits per symbol; if the NACK responses decrease or are below a threshold number over the period of time, adjust the modulation-coding scheme to increase the number of bits per symbol; and encode the feedback message to include an indication of an adjustment of the modulation-coding scheme.

16 . The computer-readable storage medium of claim 15 ,
wherein to adjust the modulation-coding scheme comprises only adjusting the modulation-coding scheme every X number of received ACK/NACK responses.

17 . The computer-readable storage medium of claim 13 , wherein the communication data comprises demodulation information associated with demodulation of the plurality of packets received at the V2X device over a period of time.

18 . The computer-readable storage medium of claim 17 , wherein the demodulation information comprises a demodulation reference signal (DMRS).

19 . The computer-readable storage medium of claim 18 , wherein the instructions further configure the baseband processor to:
determine an estimated channel based on the DMRS to demodulate the plurality of packets; and calculate the channel quality indicator based on long term statistics of the estimated channel.

20 . The computer-readable storage medium of claim 19 , wherein the instructions further configure the baseband processor to:
determine, based on the DMRS, an interference measurement per sub-channel; and determine the channel quality indicator by averaging or weighting both the estimated channel and the interference measurement over at least one of the period of time and a bandwidth used for transmission.

21 - 23 . (canceled)

Assignees

• Apple Inc

Inventors

• Khoryaev Alexey
• Panteleev Sergey
• Shilov Mikhail
• Gomes Baltar Leonardo
• Roth Kilian

Classifications

• H04L1/0039

  other detection of signalling, e.g. detection of TFCI explicit signalling (H04L1/0046, H04L27/0012 and H04L25/0262 take precedence) · CPC title

• H04L1/0009

  by adapting the channel coding (H04L1/1812 takes precedence) · CPC title

• H04L1/0003

  by switching between different modulation schemes · CPC title

• H04L1/0026

  Transmission of channel quality indication · CPC title

• H04L5/0055

  Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861) · CPC title