CROSS REFERENCE

The present Application for patent claims the benefit of Greece Provisional Patent Application No. 20190100428 by DUAN et al., entitled “IMPLICIT SIGNALING OF LARGE-SCALE CHANNEL PROPERTIES ACROSS MULTIPLE TRACKING REFERENCE SIGNAL TRANSMISSIONS,” filed Oct. 2, 2019, assigned to the assignee hereof, and expressly incorporated by reference herein.

BACKGROUND

The following relates generally to wireless communications, and more specifically to implicit signaling of large-scale channel properties across multiple tracking reference signal transmissions.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).

Wireless communications systems may use various configurations to support wireless transmissions/receptions. For example, beam configurations may be used to select or otherwise identify various parameters to be used for wireless communications employing beamforming (e.g., millimeter wave (mmW) communications). Beam configurations may include spatial relation information for uplink resources, or quasi-colocated (QCL) information for downlink resources. Beam configurations may include, for example, beam direction, beam identifier, spatial stream, and the like. Beam configurations may include transmit beam configurations and receive beam configurations, and the transmitters and receivers may update beam configurations in response to changes in channel conditions. Reference signals transmitted between devices may be used to update beam configurations, and the devices may use channel reciprocity to update transmit beam configurations based on a receive beam configuration determined for a reference signal. Further, some reference signals transmitted between devices may be used for time/frequency tracking at a UE to allow for time tracking loops and/or frequency tracking loops to be maintained. Such reference signals may include periodic reference signals, aperiodic reference signals, or combinations thereof. However, changes to beam configurations used for reference signal transmissions may impact beam parameters derived from measurements of the reference signals. Thus, efficient determination of beam configurations for reference signal transmissions may enhance the efficiency and reliability of communications.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support implicit signaling of large-scale channel properties across multiple tracking reference signal transmissions. Various described techniques provide for multiple instances of one or more aperiodic tracking reference signals that are transmitted using a same set of large-scale channel properties that are separate from large scale parameters of one or more periodic reference signals. In some cases, two or more aperiodic tracking reference signals may be triggered by downlink control information from a base station that indicates a same transmission configuration indicator state for slots containing the two or more aperiodic tracking reference signals. A UE that receives the two or more aperiodic tracking reference signals may measure the multiple instances of the aperiodic tracking reference signals assuming that the same large scale parameters or properties (e.g., quasi co-location (QCL) parameters) can be inferred from each of the aperiodic tracking reference signals. The UE may then update one or more time tracking parameters, frequency tracking parameters, or combinations thereof, based on the same large scale transmission parameters being used for the multiple instances of the aperiodic tracking reference signal. Such techniques may enhance the reliability of time/frequency tracking at the UE, and also provide processing gain at the UE through the application of the same large scale parameters across multiple instances of a reference signal.

A method of wireless communication at a UE is described. The method may include receiving, from a base station, downlink control information that includes a first transmission configuration indicator state for at least a first slot, and that includes a trigger for an aperiodic tracking reference signal in at least the first slot, measuring a first instance of the aperiodic tracking reference signal in the first slot and a second instance of the aperiodic tracking reference signal in the first slot or a second slot, and updating one or more time tracking parameters, frequency tracking parameters, or combinations thereof based on a same first set of large scale transmission parameters being used for at least the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive, from a base station, downlink control information that includes a first transmission configuration indicator state for at least a first slot, and that includes a trigger for an aperiodic tracking reference signal in at least the first slot, measure a first instance of the aperiodic tracking reference signal in the first slot and a second instance of the aperiodic tracking reference signal in the first slot or a second slot, and update one or more time tracking parameters, frequency tracking parameters, or combinations thereof based on a same first set of large scale transmission parameters being used for at least the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving, from a base station, downlink control information that includes a first transmission configuration indicator state for at least a first slot, and that includes a trigger for an aperiodic tracking reference signal in at least the first slot, measuring a first instance of the aperiodic tracking reference signal in the first slot and a second instance of the aperiodic tracking reference signal in the first slot or a second slot, and updating one or more time tracking parameters, frequency tracking parameters, or combinations thereof based on a same first set of large scale transmission parameters being used for at least the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to receive, from a base station, downlink control information that includes a first transmission configuration indicator state for at least a first slot, and that includes a trigger for an aperiodic tracking reference signal in at least the first slot, measure a first instance of the aperiodic tracking reference signal in the first slot and a second instance of the aperiodic tracking reference signal in the first slot or a second slot, and update one or more time tracking parameters, frequency tracking parameters, or combinations thereof based on a same first set of large scale transmission parameters being used for at least the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first transmission configuration indicator state indicates the first set of large scale transmission parameters.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving configuration information from the base station that includes a configuration for a periodic tracking reference signal, where a second transmission configuration indicator state that indicates a second set of large scale transmission parameters for the periodic tracking reference signal is semi-statically indicated by the base station, and where the second set of large scale transmission parameters is different than the first set of large scale transmission parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second transmission configuration indicator state is semi-statically indicated in one or more periodic synchronization signal blocks. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of large scale transmission parameters include quasi co-location (QCL) parameters that are used for the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the downlink control information may be received in a first downlink control information transmission in a first downlink control channel monitoring occasion of the first slot that triggers the first instance of the aperiodic tracking reference signal and in a second downlink control information transmission in a second downlink control channel monitoring occasion of the second slot that triggers the second instance of the aperiodic tracking reference signal within the second slot. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the aperiodic tracking reference signal may be a first aperiodic tracking reference signal, and where the downlink control information further triggers one or more additional instances of the first aperiodic tracking reference signal or one or more other aperiodic tracking reference signals.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first downlink control information transmission and the second downlink control information transmission both indicate the first transmission configuration indicator state, and where the UE assumes the first set of large scale transmission parameters is used for both the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal when measuring the aperiodic tracking reference signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the downlink control information may be received in a first downlink control information transmission in a downlink control channel monitoring occasion of the first slot that triggers the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal within the second slot. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the downlink control information is received in both a first downlink control information transmission and a second downlink control information transmission that are transmitted in one or more of a first downlink control channel monitoring occasion or a second downlink control channel monitoring occasion. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first downlink control information transmission and the second downlink control information transmission are both received in the first downlink control channel monitoring occasion. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first downlink control information transmission is received in the first downlink control channel monitoring occasion and the second downlink control information transmission is received in the second downlink control channel monitoring occasion that is consecutive to the first downlink control channel monitoring occasion.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first downlink control information transmission is received in the first downlink control channel monitoring occasion and the second downlink control information transmission is received in the second downlink control channel monitoring occasion that is non-consecutive to the first downlink control channel monitoring occasion, and where both the first downlink control channel monitoring occasion and the second downlink control channel monitoring occasion are in the first slot.

A method of wireless communication at a base station is described. The method may include transmitting, to a UE, downlink control information that includes a first transmission configuration indicator state for at least a first slot, and that includes a trigger for an aperiodic tracking reference signal in at least the first slot and a second slot, transmitting a first instance of the aperiodic tracking reference signal in the first slot and a second instance of the aperiodic tracking reference signal in the second slot, where a same first set of large scale transmission parameters is used for both the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal, and receiving a feedback report that includes one or more parameters that are determined based on the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

An apparatus for wireless communication at a base station is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to transmit, to a UE, downlink control information that includes a first transmission configuration indicator state for at least a first slot, and that includes a trigger for an aperiodic tracking reference signal in at least the first slot and a second slot, transmit a first instance of the aperiodic tracking reference signal in the first slot and a second instance of the aperiodic tracking reference signal in the second slot, where a same first set of large scale transmission parameters is used for both the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal, and receive a feedback report that includes one or more parameters that are determined based on the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

Another apparatus for wireless communication at a base station is described. The apparatus may include means for transmitting, to a UE, downlink control information that includes a first transmission configuration indicator state for at least a first slot, and that includes a trigger for an aperiodic tracking reference signal in at least the first slot and a second slot, transmitting a first instance of the aperiodic tracking reference signal in the first slot and a second instance of the aperiodic tracking reference signal in the second slot, where a same first set of large scale transmission parameters is used for both the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal, and receiving a feedback report that includes one or more parameters that are determined based on the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to transmit, to a UE, downlink control information that includes a first transmission configuration indicator state for at least a first slot, and that includes a trigger for an aperiodic tracking reference signal in at least the first slot and a second slot, transmit a first instance of the aperiodic tracking reference signal in the first slot and a second instance of the aperiodic tracking reference signal in the second slot, where a same first set of large scale transmission parameters is used for both the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal, and receive a feedback report that includes one or more parameters that are determined based on the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first transmission configuration indicator state indicates the first set of large scale transmission parameters.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting configuration information to the UE that includes a configuration for a periodic tracking reference signal, where a second transmission configuration indicator state that indicates a second set of large scale transmission parameters for the periodic tracking reference signal is semi-statically indicated to the UE, and where the second set of large scale transmission parameters is different than the first set of large scale transmission parameters. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second transmission configuration indicator state may be semi-statically indicated in one or more periodic synchronization signal blocks. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first set of large scale transmission parameters include quasi co-location (QCL) parameters that may be used for the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the downlink control information may be transmitted in a first downlink control information transmission in a first downlink control channel monitoring occasion of the first slot that triggers the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the aperiodic tracking reference signal may be a first aperiodic tracking reference signal, and where the downlink control information is further transmitted in a second downlink control information transmission in a second downlink control channel monitoring occasion of the second slot that triggers one or more instances of a second aperiodic tracking reference signal in one or other slots.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first downlink control information transmission and the second downlink control information transmission both indicate the first transmission configuration indicator state, and where the UE assumes the first set of large scale transmission parameters is used for both the first aperiodic tracking reference signal and the second aperiodic tracking reference signal when measuring the first aperiodic tracking reference signal and the second aperiodic tracking reference signal. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the downlink control information may be transmitted in a first downlink control information transmission in a downlink control channel monitoring occasion of the first slot that triggers the first instance of the aperiodic tracking reference signal and the second instance of the aperiodic tracking reference signal within the second slot.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the downlink control information is transmitted in both a first downlink control information transmission and a second downlink control information transmission that is provided in one or more downlink control channel monitoring occasions of one or more slots. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first downlink control information transmission and the second downlink control information transmission are both provided in the first downlink control channel monitoring occasion. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first downlink control information transmission is provided in a first downlink control channel monitoring occasion and the second downlink control information transmission is provided in a second downlink control channel monitoring occasion that is consecutive to the first downlink control channel monitoring occasion. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first downlink control information transmission is provided in a first downlink control channel monitoring occasion and the second downlink control information transmission is provided in a second downlink control channel monitoring occasion that is non-consecutive to the first downlink control channel monitoring occasion, and where both the first downlink control channel monitoring occasion and the second downlink control channel monitoring occasion are in the first slot.

