Method and apparatus for receiver assisted transmission in shared spectrum
An access node such as a gNB, when determining that a communication channel in a shared spectrum is clear, may send downlink control information (DCI) triggering a user equipment (UE) to measure a resource to determine whether the communication channel is available for the UE. The UE, triggered by the DCI, may measure received energy on resource, generate a measurement report and send the measurement report to the access node. The access node may determine whether to transmit data to the UE in the communication channel based on the measurement report.
1 . A method performed by an apparatus, the method comprising:
determining whether a communication channel in a shared spectrum is clear for use when data is to be sent to a first UE by the apparatus;
sending, upon determining that the communication channel is clear, a first control information message triggering the first UE to measure a layer 1 (L1) resource to determine whether the communication channel is available for the first UE;
receiving, from the first UE after sending the first control information message, a first measurement report of measurement of the L1 resource;
determining whether to transmit the data to the first UE in the communication channel based on the first measurement report;
transmitting, based on the first measurement report that the communication channel is available for the first UE, the data to the first UE in the communication channel;
receiving from the first UE a negative acknowledge (NACK) message indicating that the data has not been successfully received by the first UE;
receiving, from the first UE after receiving the NACK message, a second measurement report of measurement of the L1 resource; and
retransmitting the data to the first UE in the communication channel when determining, based on the second measurement report, that the communication channel is available for the first UE.
2 . The method of claim 1 , further comprising:
determining that the communication channel is available after receiving the first measurement report and before transmitting the data.
3 . The method of claim 1 , wherein the data is transmitted in the L1 resource or in a subset of the L1 resource.
4 . The method of claim 1 , further comprising:
sending, upon determining that the communication channel is unavailable for the first UE, a second control information message triggering the first UE to re-measure the L1 resource to determine whether the communication channel is available for the first UE.
5 . The method of claim 1 , wherein when the second UE apparatus has determined that the communication channel is unavailable for the first UE, the method further comprises:
receiving, from the first UE within a preset period after receiving the first measurement report, the second measurement report; and
transmitting the data to the first UE upon determining, based on the second measurement report, that the communication channel is available for the first UE.
6 . The method of claim 1 , wherein the first measurement report indicates:
whether detected energy on the L1 resource or a subset of the L1 resource exceeds a threshold;
whether the L1 resource or the subset of the L1 resource is idle; or
the detected energy on the L1 resource or the subset of the L1 resource.
7 . The method of claim 1 , wherein the first measurement report comprises an interference measurement indicator (IMI) indicating a measurement result of the L1 resource or a subset of the L1 resource.
8 . The method of claim 1 , further comprising:
transmitting information comprising any one or more of following:
a resource for reporting a resource measurement;
quasi co-location (QCL) information of a measurement resource;
a transmission configuration indication (TCI) state indicating a QCL type of the measurement resource;
a measurement time period of the resource measurement; or
a measurement threshold.
9 . The method of claim 1 , wherein transmitting the first control information message comprises:
transmitting the first control information message to a group of UEs including the first UE to trigger each of the UEs in the group to measure a corresponding resource to determine whether the communication channel is available for a corresponding UE.
10 . The method of claim 9 , wherein the first control information message has cyclic redundancy check (CRC) scrambled using a group radio network temporary identifier (RNTI) associated with the group of UEs, and the first control information message comprises, for each UE, one or more of following:
the corresponding resource of the corresponding UE;
QCL information of the corresponding resource of the corresponding UE;
a measurement time window;
a measurement threshold; or
a resource for reporting a measurement.
11 . The method of claim 1 , wherein the first control information message further comprises a field configured to request the first UE to report an L1-IM report or a CSI-RS report on the measurement of the L1 resource.
12 . The method of claim 1 , wherein the first control information message further comprises any one or more of following:
a channel state information-interference measurement (CSI-IM) time domain indicator indicating a CSI-IM configuration for an interference measurement;
a parameter Periodicity-and-Offset indicating a periodicity and a timing offset for the interference measurement and reporting; or
a parameter IMI Bit Length indicating a number of bits used to encode a measurement result of the interference measurement.
13 . The method of claim 1 , wherein the first control information message further includes identification information of a group of destination UEs, and the apparatus receives the first measurement report based on the first UE being in the group of destination UEs identified by the identification information in the first control information message.
14 . A method comprising:
receiving, by a user equipment (UE), a first control information message triggering the UE to measure a layer 1 (L1) resource to determine whether a communication channel in a shared spectrum is available for the UE;
performing, by the UE upon triggered by the first control information message, a first measurement of received energy on the L1 resource;
generating, by the UE, a first measurement report based on the first measurement;
transmitting, by the UE, the first measurement report;
receiving, by the UE when the communication channel is available for the UE, data in the communication channel of the shared spectrum after transmitting the first measurement report;
transmitting, by the UE, a negative acknowledge (NACK) message indicating that the data is not successfully received by the UE;
performing, by the UE, a second measurement of received energy on the L1 resource to determine whether the communication channel is available;
transmitting, by the UE, a second measurement report, the second measurement report based on the second measurement; and
receiving, by the UE after transmitting the second measurement report, the data retransmitted in the communication channel of the shared spectrum.
15 . The method of claim 14 , further comprising:
receiving, by the UE when the communication channel is unavailable for the UE, a second control information message triggering the UE to re-measure the L1 resource to determine whether the communication channel is available.
16 . An apparatus comprising:
a non-transitory memory storage comprising instructions; and
one or more processors in communication with the non-transitory memory storage, wherein the instructions, when executed by the one or more processors, cause the apparatus to perform:
determining whether a communication channel in a shared spectrum is clear for use when data is to be sent to a first user equipment (UE) by the apparatus;
sending, upon determining that the communication channel is clear, a first control information message triggering the first UE to measure a layer 1 (L1) resource to determine whether the communication channel is available for the first UE;
receiving, from the first UE after sending the first control information message, a first measurement report of measurement of the L1 resource;
determining whether to transmit the data to the first UE in the communication channel based on the first measurement report;
transmitting, based on the first measurement report that the communication channel is available for the first UE, the data to the first UE in the communication channel;
receiving from the first UE a negative acknowledge (NACK) message indicating that the data has not been successfully received by the first UE;
receiving, from the first UE after receiving the NACK message, a second measurement report of measurement of the L1 resource; and
retransmitting the data to the first UE in the communication channel when determining, based on the second measurement report, that the communication channel is available for the first UE.