Enhanced tracking reference signal patterns

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit, to a base station, a UE capability to receive a first portion of a tracking reference signal (TRS) and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The UE may receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The UE may receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

INTRODUCTION

The following relates to wireless communications and more specifically to managing tracking reference signal (TRS) patterns.

SUMMARY

A method for wireless communications at a UE is described. The method may include transmitting, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, receiving, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs, and receiving one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

An apparatus for wireless communications at a UE is described. The apparatus may include a processor and memory coupled to the processor, the memory and processor configured to transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs, and receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Another apparatus for wireless communications at a UE is described. The apparatus may include means for transmitting, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, means for receiving, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs, and means for receiving one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

A non-transitory computer-readable medium storing code for wireless communications at a UE is described. The code may include instructions executable by a processor to transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs, and receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a request for the second portion of the TRS pattern to the base station.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for detecting the UE may be moving at a speed that satisfies a speed threshold, where the request may be transmitted based on the detecting.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for selecting the TRS pattern from a table of patterns based on the indication of the TRS pattern.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a medium access control (MAC) control element (CE) from the base station indicating the table of patterns from a set of multiple tables of patterns.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication of the TRS pattern corresponds an index of the table of patterns.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving radio resource control (RRC) signaling from the base station configuring the table of patterns.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication of the TRS pattern may be received via downlink control information (DCI).

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the TRS pattern may include operations, features, means, or instructions for receiving DCI allocating an aperiodic resource for the set of multiple TRSs.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an indication of a triggering state from the base station via DCI or a MAC-CE, where the TRS pattern may be based on the triggering state.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a TRS of the second portion of the TRS pattern may be between TRSs of the first portion, before the TRSs of the first portion, or after the TRSs of the first portion.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the TRS pattern spans a slot or a set of multiple slots.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for performing a time and frequency synchronization based on receiving the one or more TRSs.

A method for wireless communications at a base station is described. The method may include receiving, from a UE, an indication of a UE capability, transmitting, to the UE, an indication of a TRS pattern including a first portion and a second portion for a set of multiple TRSs based on the received indication of the UE capability, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs, and transmitting the set of multiple TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

An apparatus for wireless communications at a base station is described. The apparatus may include a processor and memory coupled to the processor, the memory and processor configured to receive, from a UE, an indication of a UE capability, transmit, to the UE, an indication of a TRS pattern including a first portion and a second portion for a set of multiple TRSs based on the received indication of the UE capability, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs, and transmit the set of multiple TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Another apparatus for wireless communications at a base station is described. The apparatus may include means for receiving, from a UE, an indication of a UE capability, means for transmitting, to the UE, an indication of a TRS pattern including a first portion and a second portion for a set of multiple TRSs based on the received indication of the UE capability, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs, and means for transmitting the set of multiple TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

A non-transitory computer-readable medium storing code for wireless communications at a base station is described. The code may include instructions executable by a processor to receive, from a UE, an indication of a UE capability, transmit, to the UE, an indication of a TRS pattern including a first portion and a second portion for a set of multiple TRSs based on the received indication of the UE capability, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs, and transmit the set of multiple TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a request for the second portion of the TRS pattern from the UE based on a high speed of the UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication of the TRS pattern corresponds to an index of a table of patterns configured at the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a MAC-CE, to the UE indicating the table of patterns from a set of multiple tables of patterns.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting RRC signaling to the UE configuring the table of patterns.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication of the TRS pattern may be transmitted via DCI.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the indication of the TRS pattern may include operations, features, means, or instructions for transmitting DCI allocating an aperiodic resource for the set of multiple TRSs.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an indication of a triggering state from the base station via DCI or a MAC-CE, where the TRS pattern may be based on the triggering state.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a TRS of the second portion of the TRS pattern may be between TRSs of the first portion, before the TRSs of the first portion, or after the TRSs of the first portion.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the indication of the TRS pattern to a second UE that may be incapable of receiving the second portion of the TRS pattern and scheduling a downlink shared channel resource for the second UE, where the downlink shared channel resource at least partially overlaps with the second portion of the TRS in time, frequency, antenna port, or any combination thereof, based on a modulation and coding scheme of the second UE being low.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for scheduling a second UE for a downlink shared channel during a slot including the set of multiple TRSs, where the second UE may be incapable of receiving the second portion of the TRS pattern and transmitting the indication of the TRS pattern to the second UE, where the indication configures the second UE for a zero-power channel state information reference signal during the second portion of the TRS pattern.

A method for wireless communications at a UE is described. The method may include transmitting, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, receiving, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern and monitoring for a set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

An apparatus for wireless communications at a UE is described. The apparatus may include a processor and memory coupled to the processor. The processor and memory being configured to transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The processor and memory may be further configured to receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. In addition, the processor and memory may be configured to monitor for a set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Another apparatus for wireless communications at a UE is described. The apparatus may include means for transmitting, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, means for receiving, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern, and means for monitoring for a set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

A non-transitory computer-readable medium storing code for wireless communications at a UE is described. The code may include instructions executable by a processor to transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern, and monitor for a set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a request for the second portion of the TRS pattern to the base station.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for detecting the UE may be moving at a speed that satisfies a speed threshold, where the request may be transmitted based on the detecting.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for selecting the TRS pattern from a table of patterns based on the indication of the TRS pattern.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a MAC-CE from the base station indicating the table of patterns from a set of tables of patterns.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication of the TRS pattern corresponds an index of the table of patterns.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving RRC signaling from the base station configuring the table of patterns.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication of the TRS pattern may be received via DCI.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the TRS pattern may include operations, features, means, or instructions for receiving DCI allocating an aperiodic resource for the set of TRS.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an indication of a triggering state from the base station via DCI or a MAC-CE, where the TRS pattern may be based on the triggering state.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first portion of the TRS pattern includes a four symbol gap between TRS, and the first portion and the second portion of the TRS pattern include a smaller symbol gap (e.g., fewer symbols than a four symbol gap) between at least two TRS.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a TRS of the second portion of the TRS pattern may be between TRS of the first portion, before the TRS of the first portion, or after the TRS of the first portion.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the TRS pattern spans a slot or a set of slots.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

A method for wireless communications at a base station is described. The method may include receiving, from a UE, a UE capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern, selecting the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability, transmitting, to the UE, an indication of the TRS pattern, and transmitting the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

An apparatus for wireless communications at a base station is described. The apparatus may include a processor and memory coupled to the processor. The processor and memory may be configured to receive, from a UE, a UE capability to receive a first portion of a TRS and a second portion of a TRS. The first portion and the second portion may be associated with a TRS pattern. The processor and memory may be further configured to select the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability. The processor and memory may be further configured to transmit, to the UE, an indication of the TRS pattern. In addition, the processor and memory may be configured to transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Another apparatus for wireless communications at a base station is described. The apparatus may include means for receiving, from a UE, a UE capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern, means for selecting the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability, means for transmitting, to the UE, an indication of the TRS pattern, and means for transmitting the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

A non-transitory computer-readable medium storing code for wireless communications at a base station is described. The code may include instructions executable by a processor to receive, from a UE, a UE capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern, select the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability, transmit, to the UE, an indication of the TRS pattern, and transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a request for the second portion of the TRS pattern from the UE based on a high speed of the UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication of the TRS pattern corresponds to an index of a table of patterns configured at the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a MAC-CE to the UE indicating the table of patterns from a set of tables of patterns.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting RRC signaling to the UE configuring the table of patterns.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication of the TRS pattern may be transmitted via DCI.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the indication of the TRS pattern may include operations, features, means, or instructions for transmitting DCI allocating an aperiodic resource for the set of TRS.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an indication of a triggering state from the base station via DCI or a MAC-CE, where the TRS pattern may be based on the triggering state.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first portion of the TRS pattern includes a four symbol gap between TRS, and the first portion and the second portion of the TRS pattern include a two symbol gap between at least two TRS.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, a TRS of the second portion of the TRS pattern may be between TRS of the first portion, before the TRS of the first portion, or after the TRS of the first portion.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the TRS pattern spans a slot or a set of slots.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the indication of the TRS pattern to a second UE that may be incapable of receiving the second portion of the TRS pattern, and scheduling a downlink shared channel resource for the second UE, where the downlink shared channel resource at least partially overlaps with the second portion of the TRS in time, frequency, antenna port, or any combination thereof, based on a modulation and coding scheme of the second UE being low.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for scheduling a second UE for a downlink shared channel during a slot including the set of TRS, where the second UE may be incapable of receiving the second portion of the TRS pattern, and transmitting the indication of the TRS pattern to the second UE, where the indication configures the second UE for a zero-power channel state information reference signal during the second portion of the TRS pattern.

DETAILED DESCRIPTION

Some wireless communications systems support a TRS for fine time and frequency tracking of UE. For example, a UE may receive one or more TRSs transmitted by a base station, and the UE may track frequency and time variations with a high resolution when communicating with the base station based on the received TRS. A TRS may be configured on a channel state information reference signal (CSI-RS) resource set. In some examples, a TRS may be configured on a UE-specific basis. In some examples, multiple UEs may be configured to share a TRS. In some examples, TRSs may be transmitted according to a pattern. For example, in some wireless communications systems, a set of TRSs may be transmitted with a four symbol gap between the TRSs in a slot according to the TRS pattern. For example, a TRS pattern of some other wireless communications may use a TRS pattern with two TRSs, where a first TRS is transmitted in symbol period4and a second TRS is transmitted in symbol period8. A UE may search for the TRS within a pull-in signal range, where the UE can detect a signal as long as the signal is within the pull-in signal range of the originally allocated frequency. The pull-in signal range may be a distance from a transmitting device, where receiving devices within the distance of the pull-in signal range may be able to coherently decode a signal from the transmitting device. The pull-in signal range may compensate for effects such as doppler shift, which may affect a frequency of a transmission in relation to movement of the UE. If the UE detects the TRS, the UE may use the TRS to perform time and frequency tracking, such as performing central frequency offset estimation.

Some wireless communications using a TRS may also support wireless communications with high speed devices. For example, a wireless communications network may provide service for a UE on a high speed train. When a UE is in a high speed scenario, a maximum doppler shift may be close to, or exceed, a pull-in range for carrier frequency offset estimation. The maximum pull-in range for carrier frequency offset estimation of TRS may be based on the interval between TRS symbols. For example, for TRS patterns used by some systems, the maximum pull-in range may be very close to the maximum doppler shift of a UE on a high speed train. This may lead to some situations where a UE on a high speed train cannot acquire the TRS to perform carrier frequency offset estimation, and the UE and serving cell cannot reliably perform the fine time/frequency tracking.

A UE and a base station described herein may implement techniques to configure the UE with an enhanced TRS pattern, where more TRSs are transmitted in a given time period. With the enhanced TRS pattern, there may be, for example, just one symbol period between TRS transmissions, which may provide a larger pull-in range. For example, instead of a TRS symbol interval of four symbols, additional TRS may be transmitted such that the TRS symbol interval is reduced to two symbols. This may approximately double the pull-in range for the UE, preventing the doppler shift from exceeding the maximum pull-in range and enabling the UE to reliably acquire the TRS and perform fine time and frequency tracking. The enhanced TRS pattern may be backward-compatible with other systems. For example, the enhanced TRS pattern may include a first portion of TRS and a second portion of TRS. The first portion of TRS may be the TRS pattern of other systems, and the second portion may include additional TRS to provide a smaller symbol interval between transmissions of each TRS. This may enable both UEs having the capability and UEs not having the capability to still use the same TRS, as UEs on the same train may likely be offered the same TRS. A UE may indicate its capability to support the second portion of the TRS pattern, and the base station may configure the UE for the TRS pattern with the first portion and second portion based on the UE capability. These techniques may enable a UE to perform time and frequency synchronization using one or more TRSs in a high speed scenario. These techniques may provide for higher quality communications links between a UE in a high speed scenario (e.g., on a high speed train) and serving cells.

The wireless communications system100may support a TRS for fine time and frequency tracking of a UE115. Some wireless communications systems may not support a CRS. In some cases, TRS may be transmitted on a wide-band and in regular bursts. The parameters for a burst structure may include a TRS burst length in terms of a number of slots and the TRS burst periodicity in terms of a number of slots.

A TRS may be configured on a CSI-RS resource set. For example, some common values for non-zero power CSI-RS in the CSI-RS resource set may be configured for TRS to reduce signaling overhead. TRSs may be UE-specifically managed and configured on a UE-specific basis, though multiple UEs115may be configured to share a TRS. Demodulation reference signal (DMRS) and TRS may be time division multiplexed from a UE115perspective. TRSs may be configured on a carrier or on an active bandwidth part when a synchronization signal block is not present. A TRS may be quasi co-located with a downlink shared channel DMRS, at least for delay spread, average delay, doppler shift, and doppler spread. A TRS sequence may be based on a pseudorandom noise generator, which may be similar to CSI-RS. For a connected mode UE115, the UE115may be expected to receive UE-specific configuration of TRS for sub-6 GHz communications and above-6 GHz communications.

In some examples, TRSs may be transmitted according to a pattern. For example, in some wireless communications systems, a set of TRSs may be transmitted with a four symbol gap between the TRSs in a slot according to the TRS pattern.

The UE115may search for the TRSs within a pull-in signal range. If the UE115detects the TRSs, the UE115may use the TRSs to perform the fine time and frequency tracking. In some examples, the maximum pull in range, |f|, may be determined based on the interval between TRS symbols according to N*Ts*pi*|f|<pi, where N is the gap between symbol periods and Ts is the symbol duration. For a TRS pattern with a four symbol period interval between TRSs, the pull-in range for a 120 kHz subcarrier spacing may be 14 kHz.

Some wireless communications using a TRS may also support wireless communications with high speed devices. For example, a wireless communications network may provide service for a UE115on a high speed train, vehicle, etc. When a UE115is in a high speed scenario, a maximum doppler shift may be close to, or exceed, a pull-in range for carrier frequency offset estimation. A doppler shift for a UE115on a high speed train may be as high as, for example 13.9 kHz. Therefore, for TRS patterns used by some systems, the maximum pull-in range may be very close to the maximum doppler shift of a UE115on a high speed train. This may lead to some situations where a UE115on a high speed train cannot acquire the TRS to perform carrier frequency offset estimation, and the UE115and serving cell cannot reliably perform the fine time/frequency tracking. Additionally, communicating at a high carrier frequency may increase the doppler shift. For example, the open loop frequency synchronization in some radio frequency components may be difficult to achieve at high frequencies.

A UE115described herein may be configured with an enhanced TRS pattern, where more TRSs are transmitted in a given time period. With the enhanced TRS pattern, there may be a smaller interval between TRS transmissions, which may provide a larger pull-in range or a pull-in range with a greater distance. For example, instead of a TRS symbol interval of four symbols, additional TRS may be transmitted such that the TRS symbol interval is reduced to two symbols. This may double the pull-in range for the UE115, preventing the doppler shift from exceeding the maximum pull-in range and enabling the UE115to reliably acquire the TRS and perform fine time and frequency tracking. The enhanced TRS pattern may be backward-compatible with other systems. For example, the enhanced TRS pattern may include a first portion of TRS and a second portion of TRS. The first portion of TRS may be the TRS pattern of other systems, and the second portion may include additional TRS to provide a smaller symbol interval between transmissions of each TRS. This may enable both capable and incapable UEs115to still use the same TRS, as UEs115on the same train may likely be offered the same TRS. A UE115may indicate its capability to support the second portion of the TRS pattern, and the base station may configure the UE115for the TRS pattern with the first portion and second portion based on the UE capability.

In various examples, a communication manager101may be included in a device to support enhanced TRS patterns with a higher density of TRSs in a TRS pattern. For example, a UE115may include a communications manager101-a, or a base station may include a communications manager110-b.

In some examples, a communication manager101may transmit, to a base station105, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The communication manager101may receive, from the base station105, an indication of the TRS pattern. In some cases, the TRS pattern may include the first portion of the TRS pattern and the second portion of the TRS pattern. The communication manager101may monitor for a set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

In some examples, a communication manager101may receive, from a UE115, a UE capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern. The communication manager101may select the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability. The communication manager101may transmit, to the UE115, an indication of the TRS pattern. The communication manager101may transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

In some examples, a communication manager101may transmit, to a base station105, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The communication manager101may receive, from the base station105, an indication of the TRS pattern. In some cases, the TRS pattern may include the first portion of the TRS pattern and the second portion of the TRS pattern. In some cases, the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap (e.g., of at least one symbol) between at least two TRSs. The communication manager101may receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

In some examples, a communication manager101may receive, from a UE115, an indication of a UE capability. The communication manager101may transmit, to the UE, an indication of a TRS pattern including a first portion and a second portion for a set of one or more of TRSs based on the received indication of the UE capability. In some cases, the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs. The communication manager101may transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

FIG.2illustrates an example of a wireless communications system200that supports enhanced TRS patterns in accordance with aspects of the present disclosure. In some examples, wireless communications system200may implement aspects of wireless communication system100.

The wireless communications system200may include a device205(e.g., a TRS transmitter) and a device210(e.g., a TRS receiver), where the device205and the device210may refer to various types of devices according to different types of configurations. For example, when the described reference signals are associated with downlink transmission, the device205may be a base station105and the second device210may be a UE115. For example, the device205may be an example of a base station105described with reference toFIG.1, and the device210may be an example of a UE115described with reference toFIG.1.

The wireless communications system200may support TRS schemes for fine time and frequency tracking of devices such as a device210. A TRS may be configured on a CSI-RS resource set and configured on a device-specific basis, though multiple devices210may be configured to share a TRS. In some examples, TRS may be transmitted according to a pattern. For example, in some wireless communications systems, the device205may transmit a set of TRSs including one or more TRSs according to a TRS pattern with a four symbol gap between the TRS in a slot. The device210may search for the TRS within a pull-in signal range. If the device210detects the TRS, the device210may use the TRS to perform the time and frequency tracking.

The wireless communications system200may support wireless communications with high speed devices. For example, the device210may be on a high speed train, and the device205may provide service for the device210. In some cases, the maximum pull-in range for carrier frequency offset estimation of TRS may be based on the interval between TRS symbols. When the device210is in a high speed scenario, a maximum doppler shift may be close to, or exceed, a pull-in range for carrier frequency offset estimation. For example, for TRS patterns used by some other systems, the maximum pull-in range may be very close to the maximum doppler shift of a wireless device on a high speed train. This may lead to some situations where a wireless device on a high speed train cannot acquire the TRS to perform carrier frequency offset estimation, and the wireless device and serving cell cannot reliably perform the fine time and frequency tracking.

Devices described herein, such as the device210, may be configured with an enhanced TRS pattern, where more TRSs are transmitted in a given time period. With the enhanced TRS pattern, there may be a smaller interval between TRS transmissions, which may provide a larger pull-in range. For example, instead of a TRS symbol interval of four symbols, additional TRS may be transmitted such that the TRS symbol interval is reduced to two symbols. This may approximately double the pull-in range for the device210, preventing the doppler shift from exceeding the maximum pull-in range and enabling the device210to reliably acquire the TRS and perform fine time and frequency tracking.

The enhanced TRS pattern may be backward-compatible with TRS patterns of other systems. For example, the enhanced TRS pattern may include a first portion of a TRS pattern215and a second portion of a TRS pattern220. The first portion of the TRS pattern215may correspond to the TRS pattern of other systems, and the second portion of the TRS pattern220may include additional TRS to provide a smaller symbol interval between transmissions of each TRS. This may enable both capable and incapable devices to still use the same TRS, as devices on the same train may likely be offered the same TRS. Techniques described herein, such as the enhanced TRS pattern, may be applied for devices in high speed scenarios, for devices with high mobility, with UEs115operating at on high frequency carriers, or any combination thereof.

The device210may indicate a capability230to the device205, the capability indicating support for second portion of the TRS pattern220. The device205may transmit an indication of a TRS configuration225to the device210indicating a TRS pattern with the first portion of the TRS pattern215and the second portion of the TRS pattern220based on receiving the capability230. The device205may indicate a pattern selection via RRC signaling or a MAC control element (CE). For example, the device210may have two pattern tables, corresponding to TRS patterns without the second portion and TRS patterns with the second portion. Based on a MAC-CE, the device210may select a table to use. The device205may transmit DCI to indicate an index of the selected table corresponding to a TRS pattern.

The TRS pattern with the first and second portions may have a shorter time interval between TRS transmissions than just the first portion of the TRS pattern215. In some cases, the second portion of the TRS pattern220may span the same slot as the first portion of the TRS pattern (e.g., a slot235), or the second portion of the TRS pattern220may span multiple slots. For example, there may be a first symbol gap240between TRSs transmitted according to the first portion of the TRS pattern215. For example, there may be three symbols between a first TRS transmitted according to the first pattern and a second TRS transmitted according to the first pattern. For example, TRS may be transmitted in symbol periods3and7when using just the first portion of the TRS pattern215. The second portion of the TRS pattern220, with the first portion of the TRS pattern215, may reduce a size of the symbol gaps between the TRSs. For example, there may be a second symbol gap245between TRSs when using both the first portion of the TRS pattern215and the second portion of the TRS pattern220. For example, TRS may be transmitted in symbols3,5, and7with both portions of the TRS pattern, where the second symbol gap245may be one symbol.

In some examples, the device210may transmit a request for the second portion of the TRS pattern220. For example, the device210may detect a high speed, and the device210may transmit the request, or a recommendation, based on detecting the high speed. In some cases, a table configured for the device210may be reselected (e.g., via MAC-CE) based on the speed of the device210.

In some examples, the device210may be configured for an aperiodic TRS. For an aperiodic TRS, a triggering DCI may indicate the TRS pattern. A TRS resource set of the TRS pattern may be configured in an aperiodic triggering state. DCI, a MAC-CE, or both, may indicate the triggering state corresponding to the TRS pattern from the list of trigger states. A field in the DCI may indicate whether an enhanced TRS pattern is chosen for the aperiodic TRS. In some cases, the field may be an example of a new field of a previous type of DCI, or the field may be an example of an unused field from the previous type of DCI.

By implementing these techniques, the device210may reliably acquire TRS and perform time and frequency tracking. Even in high speed scenarios, the pull-in range for TRS transmitted according to a TRS pattern with the second portion may be higher than a doppler spread of the TRS, and the TRS may be acquired by the device210.

FIG.3illustrates an example of a TRS pattern configuration300that supports enhanced TRS patterns in accordance with aspects of the present disclosure. In some examples, the TRS pattern configuration300may implement aspects of wireless communication system100.

A base station105may transmit TRS according to a TRS pattern to a UE115. The UE115may acquire the TRS and perform time and frequency tracking based on the TRS. The techniques described herein support an enhanced TRS pattern with higher density TRS, which may increase a pull-in range for the TRS. By increasing the pull-in range, a UE115traveling at a high speed may reliably acquire the TRS, even if the high speed scenario increases a doppler spread of the TRS.

The enhanced TRS pattern may include a first portion305of TRS and a second portion310of TRS. The first portion305of TRS may correspond to a TRS pattern used in other systems. By also transmitting the second portion310of TRS, a base station105may transmit TRSs with higher density within a time period. The first portion305of TRS may span a slot320. The second portion310may span the slot320or multiple slots.

A TRS may be shared by multiple UEs115. In some cases, sharing the TRS may be transparent to the UEs115. The TRS may be configured per-UE115, and the configuration may not explicitly indicate the TRS is shared with other UEs115. If, for example, multiple UEs115are in a same train, the UEs115may be configured to use the same TRS. Configuring multiple UEs115for the same TRS may reduce system overhead compared to transmitting individual TRS for UEs115.

In some examples, a base station105may configure at least two UEs115to share a TRS, where a first UE115may be capable of the enhanced TRS pattern and a second UE115may be incapable of the enhanced TRS pattern. In some examples, the base station105may transmit a TRS pattern with both the first portion305of TRS and the second portion310of TRS to increase the pull-in range for the first UE115. The second UE115may be scheduled for downlink shared channel resources315in a slot including the TRS. However, the second UE115may not be capable of receiving the second portion310of TRS. The base station105may implement techniques to avoid introducing errors for the second UE115when transmitting TRS according to the enhanced TRS pattern.

In some cases, the base station105may schedule a CSI-RS for the second UE115at the resources corresponding to the second portion310of TRS. In some cases, the base station105may schedule the second UE for a zero power CSI-RS. The second UE115may then rate match around resources with the second portion310of TRS.

In some cases, the base station105may configure the second portion310of TRS to be transmitted on a subset of a TRS bandwidth. In some cases, a TRS may be transmitted on up to 50 resource blocks. The first portion305of TRS may be transmitted on a first bandwidth (e.g., the full 50 resource blocks) of frequency325, and the second portion310of TRS may be transmitted on a subset of the first bandwidth. Based on the second portion310of TRS being transmitted on the smaller bandwidth, the downlink shared channel resources315for the second UE115may be scheduled to not overlap with the second portion310of TRS.

In some cases, the base station105may determine that a downlink shared channel modulation and coding scheme (MCS) for the second UE115is very low. If the MCS of the second UE115is low, the base station105may not adjust scheduling of the second UE115or the enhanced TRS pattern. For example, if the MCS is low, then the second UE115may still be able to successfully decode a physical downlink shared channel (PDSCH). In some example, the base station105may avoid scheduling the enhanced TRS pattern and downlink shared channel resources315for UEs115which do not support the enhanced TRS pattern in the same slot and port.

FIG.4illustrates an example of a process flow400that supports enhanced TRS patterns in accordance with aspects of the present disclosure. In some examples, process flow400may implement aspects of wireless communication system100.

The process flow400may be implemented by a UE115or a base station105, or both. For example, the process flow400may be implemented by a base station405, a UE410, or both, which may be respective examples of a base station105and a UE115.

The UE410may be an example of a capable device for receiving an enhanced TRS pattern. The enhanced TRS pattern may have additional TRS and shorter symbol period intervals between TRS transmissions. At415, UE410may transmit, to base station405, a UE capability to receive a first portion of a TRS and a second portion of the TRS. The first portion and the second portion may be associated with a TRS pattern, such as an enhanced TRS pattern described herein.

At420, base station405may select a TRS pattern including the first portion and the second portion for a set of TRSs based on receiving the UE capability. Base station405may transmit an indication of the TRS pattern to UE410at420. In some cases, the indication is transmitted via DCI. For example, UE410may be configured with TRS patterns, or tables of TRS patterns, via RRC signaling or a MAC-CE, and the DCI may indicate a TRS pattern corresponding to an index of one of the tables.

At425, UE410may monitor for the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern. At430, base station405may transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern. The UE410may receive the TRS of the first portion and the second portion and perform, for example, carrier frequency offset estimation for time and frequency tracking.

The receiver510may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to enhanced TRS patterns, or the like). Information may be passed on to other components of the device505. The receiver510may be an example of aspects of the transceiver820described with reference toFIG.8. The receiver510may utilize a single antenna or a set of antennas.

The communications manager515may transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The first portion of the TRS pattern may include a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern may include a second symbol gap between at least two TRSs. In some cases, the communications manager515may monitor for one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern. The communications manager515may receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern. The communications manager515may be an example of aspects of the communications manager810described herein.

The actions performed by the UE communications manager515as described herein may be implemented for a UE115to reliably acquire a TRS to perform time and frequency tracking. For example, if the UE115is traveling at a high speed, the UE115may implement these techniques for an enhanced TRS pattern to increase a pull-in range for the TRS, despite a higher doppler spread based on the high speed.

The communications manager515may be an example of means for performing various aspects of managing smart repeaters as described herein. The communications manager515, or its sub-components, may be implemented in hardware (e.g., in communications management circuitry). The circuitry may comprise of processor, digital signal processor (DSP), an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

In another implementation, the communications manager515, or its sub-components, may be implemented in code (e.g., as communications management software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager515, or its sub-components may be executed by a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device.

In some examples, the communications manager515may be configured to perform various operations (e.g., receiving, determining, transmitting) using or otherwise in cooperation with the receiver510, the transmitter520, or both.

The receiver610may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to enhanced TRS patterns, or the like). Information may be passed on to other components of the device605. The receiver610may be an example of aspects of the transceiver820described with reference toFIG.8. The receiver610may utilize a single antenna or a set of antennas.

The communications manager615may be an example of aspects of the communications manager515as described herein. The communications manager615may include a UE capability component620, a TRS pattern indication component625, and a TRS receiving component630. The communications manager615may be an example of aspects of the communications manager810described herein.

The UE capability component620may transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern.

The TRS pattern indication component625may receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The first portion of the TRS pattern may include a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern may include a second symbol gap between at least two TRSs.

In some cases, the TRS receiving component630may monitor for multiple TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern. The TRS receiving component630may receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

The transmitter635may transmit signals generated by other components of the device605. In some examples, the transmitter635may be collocated with a receiver610in a transceiver module. For example, the transmitter635may be an example of aspects of the transceiver820described with reference toFIG.8. The transmitter635may utilize a single antenna or a set of antennas.

FIG.7shows a block diagram700of a communications manager705that supports enhanced TRS patterns in accordance with aspects of the present disclosure. The communications manager705may be an example of aspects of a communications manager515, a communications manager615, or a communications manager810described herein. The communications manager705may include a UE capability component710, a TRS pattern indication component715, a TRS receiving component720, a TRS pattern request component725, a TRS pattern selection component730, and an aperiodic TRS component735. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The UE capability component710may transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern.

The TRS pattern indication component715may receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The first portion of the TRS pattern may include a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern may include a second symbol gap between at least two TRSs. In some cases, the indication of the TRS pattern is received via DCI. In some cases, the first portion of the TRS pattern includes a four symbol gap between TRS, and the first portion and the second portion of the TRS pattern include a smaller symbol gap between at least two TRS. In some cases, a TRS of the second portion of the TRS pattern is between TRS of the first portion, before the TRS of the first portion, or after the TRS of the first portion.

The TRS receiving component720may receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern. In some cases, the TRS pattern spans a slot or a set of slots. In some cases, the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth. In some cases, the TRS receiving component720may perform a time and frequency synchronization based on receiving the one or more tracking reference signals.

The TRS pattern request component725may transmit a request for the second portion of the TRS pattern to the base station. In some examples, the TRS pattern request component725may detect the UE is moving at a speed that satisfies a speed threshold, where the request is transmitted based on the detecting. The TRS pattern selection component730may select the TRS pattern from a table of patterns based on the indication of the TRS pattern.

In some examples, the TRS pattern selection component730may receive a MAC-CE from the base station indicating the table of patterns from a set of tables of patterns. In some examples, the TRS pattern selection component730may receive RRC signaling from the base station configuring the table of patterns. In some cases, the indication of the TRS pattern corresponds an index of the table of patterns. The aperiodic TRS component735may receive DCI allocating an aperiodic resource for the set of TRS. In some examples, the aperiodic TRS component735may receive an indication of a triggering state from the base station via DCI or a MAC-CE, where the TRS pattern is based on the triggering state.

The communications manager810may transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern, receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The first portion of the TRS pattern may include a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern may include a second symbol gap between at least two TRSs. In some cases, the communications manager810may monitor for one or more TRSs according to the first portion. The communications manager810may receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

The memory830may include random access memory (RAM) and read-only memory (ROM). The memory830may store computer-readable, computer-executable code835including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory830may contain, among other things, a basic input/output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The receiver910may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to enhanced TRS patterns, or the like). Information may be passed on to other components of the device905. The receiver910may be an example of aspects of the transceiver1220described with reference toFIG.12. The receiver910may utilize a single antenna or a set of antennas.

The communications manager915may receive, from a UE, an indication of a UE capability. In some cases, the communications manager915may receive, from a UE, an indication of a UE capability to receive a first portion of the TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The communications manager915may transmit, to the UE, an indication of a TRS pattern. The TRS pattern may include a first portion and a second portion for multiple TRSs based on the received indication of the UE capability, where the first portion of the TRS pattern may include a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern may include a second symbol gap between at least two TRSs. In some cases, the communications manager915select the TRS pattern including the first portion and the second portion for the multiple TRSs based on receiving the UE capability. The communications manager915may transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern. The communications manager915may be an example of aspects of the communications manager1210described herein.

The communications manager915may be an example of means for performing various aspects of managing smart repeaters as described herein. The communications manager915, or its sub-components, may be implemented in hardware (e.g., in communications management circuitry). The circuitry may comprise of processor, DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

In another implementation, the communications manager915, or its sub-components, may be implemented in code (e.g., as communications management software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager915, or its sub-components may be executed by a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device.

In some examples, the communications manager915may be configured to perform various operations (e.g., receiving, determining, transmitting) using or otherwise in cooperation with the receiver910, the transmitter920, or both.

The receiver1010may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to enhanced TRS patterns, or the like). Information may be passed on to other components of the device1005. The receiver1010may be an example of aspects of the transceiver1220described with reference toFIG.12. The receiver1010may utilize a single antenna or a set of antennas.

The communications manager1015may be an example of aspects of the communications manager915as described herein. The communications manager1015may include a UE capability component1020, a TRS pattern selection component1025, a TRS pattern indication component1030, and a TRS transmitting component1035. The communications manager1015may be an example of aspects of the communications manager1210described herein.

The UE capability component1020may receive, from a UE, an indication of a UE capability. In some cases, the UE capability component1020may receive, from the UE an indication of a capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern. The TRS pattern indication component1030may transmit, to the UE, an indication of a TRS pattern including a first portion and a second portion for multiple TRSs based on the received indication of the UE capability. The first portion of the TRS pattern may include a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern may include a second symbol gap between at least two TRSs. In some examples, the first symbol gap in time between multiple TRS symbols may not be sufficiently short enough to track a frequency offset or adjust a communication link for Doppler effects, such as in a high mobility scenario. Therefore, based on the UE capability, the device1005(e.g., a gNB) may include the second portion of the TRS pattern and may choose the second symbol gap such that the gap between two TRS symbols is short enough for frequency tracking, adjusting the communication link for Doppler effects, or the like. In some cases, the TRS pattern selection component1025may select the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability. The TRS transmitting component1035may transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

The transmitter1040may transmit signals generated by other components of the device1005. In some examples, the transmitter1040may be collocated with a receiver1010in a transceiver module. For example, the transmitter1040may be an example of aspects of the transceiver1220described with reference toFIG.12. The transmitter1040may utilize a single antenna or a set of antennas.

FIG.11shows a block diagram1100of a communications manager1105that supports enhanced TRS patterns in accordance with aspects of the present disclosure. The communications manager1105may be an example of aspects of a communications manager915, a communications manager1015, or a communications manager1210described herein. The communications manager1105may include a UE capability component1110, a TRS pattern selection component1115, a TRS pattern indication component1120, a TRS transmitting component1125, a TRS pattern request component1130, and a shared TRS configuration component1135. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The UE capability component1110may receive, from a UE, an indication of a UE capability. In some cases, the UE capability component1110may receive, from the UE, an indication of a UE capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern. In some cases, the TRS pattern selection component1115may select the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability. In some cases, the first portion of the TRS pattern includes a four symbol gap between TRS, and the first portion and the second portion of the TRS pattern include a two symbol gap between at least two TRS. In some cases, a TRS of the second portion of the TRS pattern is between TRS of the first portion, before the TRS of the first portion, or after the TRS of the first portion.

The TRS pattern indication component1120may transmit, to the UE, an indication of a TRS pattern. The TRS pattern may include a first portion and a second portion for multiple TRSs based on the received indication of the UE capability. The first portion of the TRS pattern may include a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern may include a second symbol gap between at least two TRSs. In some examples, the TRS pattern indication component1120may transmit a MAC-CE to the UE indicating the table of patterns from a set of tables of patterns. In some examples, the TRS pattern indication component1120may transmit RRC signaling to the UE configuring the table of patterns.

In some examples, the TRS pattern indication component1120may transmit DCI allocating an aperiodic resource for the set of TRS. In some examples, the TRS pattern indication component1120may transmit an indication of a triggering state from the base station via DCI or a MAC-CE, where the TRS pattern is based on the triggering state. In some cases, the indication of the TRS pattern corresponds to an index of a table of patterns configured at the UE. In some cases, the indication of the TRS pattern is transmitted via DCI.

The TRS transmitting component1125may transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern. In some cases, the TRS pattern spans a slot or a set of slots. In some cases, the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

The TRS pattern request component1130may receive a request for the second portion of the TRS pattern from the UE based on a high speed of the UE. The shared TRS configuration component1135may transmit the indication of the TRS pattern to a second UE that is incapable of receiving the second portion of the TRS pattern. In some examples, the shared TRS configuration component1135may schedule a downlink shared channel resource for the second UE, where the downlink shared channel resource at least partially overlaps with the second portion of the TRS in time, frequency, antenna port, or any combination thereof, based on a modulation and coding scheme of the second UE being low.

In some examples, the shared TRS configuration component1135may schedule a second UE for a downlink shared channel during a slot including the set of TRS, where the second UE is incapable of receiving the second portion of the TRS pattern. In some examples, the shared TRS configuration component1135may transmit the indication of the TRS pattern to the second UE, where the indication configures the second UE for a zero-power channel state information reference signal during the second portion of the TRS pattern.

FIG.12shows a diagram of a system1200including a device1205that supports enhanced TRS patterns in accordance with aspects of the present disclosure. The device1205may be an example of or include the components of device905, device1005, or a base station105as described herein. The device1205may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager1210, a network communications manager1215, a transceiver1220, an antenna1225, memory1230, a processor1240, and an inter-station communications manager1245. These components may be in electronic communication via one or more buses (e.g., bus1250).

The communications manager1210may receive, from a UE, an indication of a UE capability. In some cases, the communications manager1210may receive an indication of a UE capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern. In some cases, the communications manager1210may select the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability. The communications manager1210may transmit, to the UE, an indication of the TRS pattern including a first portion and a second portion for multiple TRSs based on the received indication of the UE capability. The first portion of the TRS pattern may include a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern may include a second symbol gap between at least two TRSs. The communications manager1210may transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern.

The memory1230may include RAM, ROM, or a combination thereof. The memory1230may store computer-readable code1235including instructions that, when executed by a processor (e.g., the processor1240) cause the device to perform various functions described herein. In some cases, the memory1230may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

At1305, the UE may transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The operations of1305may be performed according to the methods described herein. In some examples, aspects of the operations of1305may be performed by an UE capability component as described with reference toFIGS.5through8.

At1310, the UE may receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1310may be performed according to the methods described herein. In some examples, aspects of the operations of1310may be performed by a TRS pattern indication component as described with reference toFIGS.5through8.

At1315, the UE may monitor for a set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1315may be performed according to the methods described herein. In some examples, aspects of the operations of1315may be performed by a TRS receiving component as described with reference toFIGS.5through8.

At1405, the UE may transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The operations of1405may be performed according to the methods described herein. In some examples, aspects of the operations of1405may be performed by a UE capability component as described with reference toFIGS.5through8.

At1410, the UE may transmit a request for the second portion of the TRS pattern to the base station. The operations of1410may be performed according to the methods described herein. In some examples, aspects of the operations of1410may be performed by a TRS pattern request component as described with reference toFIGS.5through8.

At1415, the UE may receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1415may be performed according to the methods described herein. In some examples, aspects of the operations of1415may be performed by a TRS pattern indication component as described with reference toFIGS.5through8.

At1420, the UE may monitor for a set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1420may be performed according to the methods described herein. In some examples, aspects of the operations of1420may be performed by a TRS receiving component as described with reference toFIGS.5through8.

At1505, the UE may transmit, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The operations of1505may be performed according to the methods described herein. In some examples, aspects of the operations of1505may be performed by a UE capability component as described with reference toFIGS.5through8.

At1510, the UE may receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1510may be performed according to the methods described herein. In some examples, aspects of the operations of1510may be performed by a TRS pattern indication component as described with reference toFIGS.5through8.

At1515, the UE may select the TRS pattern from a table of patterns based on the indication of the TRS pattern. The operations of1515may be performed according to the methods described herein. In some examples, aspects of the operations of1515may be performed by a TRS pattern selection component as described with reference toFIGS.5through8.

At1520, the UE may monitor for a set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1520may be performed according to the methods described herein. In some examples, aspects of the operations of1520may be performed by a TRS receiving component as described with reference toFIGS.5through8.

At1605, the base station may receive, from a UE, a UE capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern. The operations of1605may be performed according to the methods described herein. In some examples, aspects of the operations of1605may be performed by a UE capability component as described with reference toFIGS.9through12.

At1610, the base station may select the TRS pattern including the first portion and the second portion for a set of TRS based on receiving the UE capability. The operations of1610may be performed according to the methods described herein. In some examples, aspects of the operations of1610may be performed by a TRS pattern selection component as described with reference toFIGS.9through12.

At1615, the base station may transmit, to the UE, an indication of the TRS pattern. The operations of1615may be performed according to the methods described herein. In some examples, aspects of the operations of1615may be performed by a TRS pattern indication component as described with reference toFIGS.9through12.

At1620, the base station may transmit the set of TRS according to the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1620may be performed according to the methods described herein. In some examples, aspects of the operations of1620may be performed by a TRS transmitting component as described with reference toFIGS.9through12.

FIG.17shows a flowchart illustrating a method1700that supports enhanced TRS patterns in accordance with aspects of the present disclosure. The operations of the method1700may be implemented by a UE or its components as described herein. For example, the operations of method1700may be performed by a communications manager as described with reference toFIGS.5through8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.

At1705, the method may include transmitting, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The operations of1705may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1705may be performed by a UE capability component as described with reference toFIGS.5through8.

At1710, the method may include receiving, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern, and where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs. The operations of1710may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1710may be performed by a TRS pattern indication component as described with reference toFIGS.5through8.

At1715, the method may include receiving one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1715may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1715may be performed by a TRS receiving component as described with reference toFIGS.5through8.

FIG.18shows a flowchart illustrating a method1800that supports enhanced TRS patterns in accordance with aspects of the present disclosure. The operations of the method1800may be implemented by a base station or its components as described herein. For example, the operations of the method1800may be performed by a base station as described with reference toFIGS.9through12. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may perform aspects of the described functions using special-purpose hardware.

At1805, the method may include receiving, from a UE, an indication of a UE capability. The operations of1805may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1805may be performed by a UE capability component as described with reference toFIGS.9through12.

At1810, the method may include transmitting, to the UE, an indication of a TRS pattern including a first portion and a second portion for a set of multiple TRSs based on the received indication of the UE capability, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs. The operations of1810may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1810may be performed by a TRS pattern indication component as described with reference toFIGS.9through12.

At1815, the method may include transmitting the set of multiple TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern. The operations of1815may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1815may be performed by a TRS transmitting component as described with reference toFIGS.9through12.

Aspect 1: A method for wireless communications at a UE, including: transmitting, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern; receiving, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs; and receiving one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Aspect 2: The method of aspect 1, further including: transmitting a request for the second portion of the TRS pattern to the base station.

Aspect 3: The method of aspect 2, further including: detecting the UE is moving at a speed that satisfies a speed threshold, where the request is transmitted based on the detecting.

Aspect 4: The method of any of aspects 1 through 3, further including: selecting the TRS pattern from a table of patterns based on the indication of the TRS pattern.

Aspect 5: The method of aspect 4, further including: receiving a MAC CE from the base station indicating the table of patterns from one or more tables of patterns.

Aspect 6: The method of any of aspects 4 through 5, where the indication of the TRS pattern corresponds an index of the table of patterns.

Aspect 7: The method of any of aspects 4 through 6, further including: receiving RRC signaling from the base station configuring the table of patterns.

Aspect 8: The method of any of aspects 1 through 7, where the indication of the TRS pattern is received via DCI.

Aspect 9: The method of any of aspects 1 through 8, where receiving the indication of the TRS pattern includes: receiving DCI allocating an aperiodic resource for the one or more TRSs.

Aspect 10: The method of aspect 9, further including: receiving an indication of a triggering state from the base station via DCI or a MAC CE, where the TRS pattern is based on the triggering state.

Aspect 11: The method of any of aspects 1 through 10, where a TRS of the second portion of the TRS pattern is between TRSs of the first portion, before the TRSs of the first portion, or after the TRSs of the first portion.

Aspect 12: The method of any of aspects 1 through 11, where the TRS pattern spans a slot or one or more slots.

Aspect 13: The method of any of aspects 1 through 12, where the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

Aspect 14: The method of any of aspects 1 through 13, further including: performing a time and frequency synchronization based on receiving the one or more TRSs.

Aspect 15: A method for wireless communications at a base station, including: receiving, from a UE, an indication of a UE capability; transmitting, to the UE, an indication of a TRS pattern including a first portion and a second portion for one or more TRSs based on the received indication of the UE capability, where the first portion of the TRS pattern includes a first symbol gap of one or more symbols between TRSs, and the first portion and the second portion of the TRS pattern include a second symbol gap between at least two TRSs; and transmitting the one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Aspect 16: The method of aspect 15, further including: receiving a request for the second portion of the TRS pattern from the UE based on a high speed of the UE.

Aspect 17: The method of any of aspects 15 through 16, where the indication of the TRS pattern corresponds to an index of a table of patterns configured at the UE.

Aspect 18: The method of aspect 17, further including: transmitting a MAC CE to the UE indicating the table of patterns from one or more tables of patterns.

Aspect 19: The method of any of aspects 17 through 18, further including: transmitting RRC signaling to the UE configuring the table of patterns.

Aspect 20: The method of any of aspects 15 through 19, where the indication of the TRS pattern is transmitted via DCI.

Aspect 21: The method of any of aspects 15 through 20, where transmitting the indication of the TRS pattern includes: transmitting DCI allocating an aperiodic resource for the one or more TRSs.

Aspect 22: The method of aspect 21, further including: transmitting an indication of a triggering state from the base station via DCI or a MAC CE, where the TRS pattern is based on the triggering state.

Aspect 23: The method of aspect 22, where a TRS of the second portion of the TRS pattern is between TRSs of the first portion, before the TRSs of the first portion, or after the TRSs of the first portion.

Aspect 24: The method of any of aspects 15 through 23, where the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

Aspect 25: The method of any of aspects 15 through 24, where the UE is a first UE, further including: transmitting the indication of the TRS pattern to a second UE that is incapable of receiving the second portion of the TRS pattern; and scheduling a downlink shared channel resource for the second UE, where the downlink shared channel resource at least partially overlaps with the second portion of the TRS in time, frequency, antenna port, or any combination thereof, based on a modulation and coding scheme of the second UE being low.

Aspect 26: The method of any of aspects 15 through 25, where the UE is a first UE, further including: scheduling a second UE for a downlink shared channel during a slot including the one or more TRSs, where the second UE is incapable of receiving the second portion of the TRS pattern; and transmitting the indication of the TRS pattern to the second UE, where the indication configures the second UE for a zero-power channel state information reference signal during the second portion of the TRS pattern.

Aspect 27: An apparatus for wireless communications at a UE, including a processor; and memory coupled to the processor, the processor and memory configured to perform a method of any of aspects 1 through 14.

Aspect 28: An apparatus for wireless communications at a UE, including at least one means for performing a method of any of aspects 1 through 14.

Aspect 29: A non-transitory computer-readable medium storing code for wireless communications at a UE, the code including instructions executable by a processor to perform a method of any of aspects 1 through 14.

Aspect 30: An apparatus for wireless communications at a base station, including a processor; and memory coupled to the processor, the processor and memory configured to perform a method of any of aspects 15 through 26.

Aspect 31: An apparatus for wireless communications at a base station, including at least one means for performing a method of any of aspects 15 through 26.

Aspect 32: A non-transitory computer-readable medium storing code for wireless communications at a base station, the code including instructions executable by a processor to perform a method of any of aspects 15 through 26.

Aspect 33: A method for wireless communications at a user equipment (UE), including: transmitting, to a base station, a UE capability to receive a first portion of a TRS and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern; receiving, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern; and monitoring for one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Aspect 34: The method of aspect 33, further including: transmitting a request for the second portion of the TRS pattern to the base station.

Aspect 35: The method of any of aspects 33 or 34, further including: detecting the UE is moving at a speed that satisfies a speed threshold, where the request is transmitted based on the detecting.

Aspect 36: The method of any of aspects 33 through 35, further including: selecting the TRS pattern from a table of patterns based on the indication of the TRS pattern.

Aspect 37: The method of any of aspects 33 through 36, further including: receiving a MAC-CE from the base station indicating the table of patterns from one or more tables of patterns.

Aspect 38: The method of any of aspects 33 through 37, where the indication of the TRS pattern corresponds an index of the table of patterns.

Aspect 39: The method of any of aspects 33 through 38, further including: receiving RRC signaling from the base station configuring the table of patterns.

Aspect 40: The method of any of aspects 33 through 39, where the indication of the TRS pattern is received via DCI.

Aspect 41: The method of any of aspects 33 through 40, where receiving the indication of the TRS pattern includes: receiving DCI allocating an aperiodic resource for the one or more TRSs.

Aspect 42: The method of any of aspects 33 through 41, further including: receiving an indication of a triggering state from the base station via DCI or a MAC-CE, where the TRS pattern is based on the triggering state.

Aspect 43: The method of any of aspects 33 through 42, where the first portion of the TRS pattern includes a four symbol gap between TRSs, and the first portion and the second portion of the TRS pattern include a smaller symbol gap between at least two TRSs.

Aspect 44: The method of any of aspects 33 through 43, where a TRS of the second portion of the TRS pattern is between TRSs of the first portion, before the TRSs of the first portion, or after the TRSs of the first portion.

Aspect 45: The method of any of aspects 33 through 44, where the TRS pattern spans a slot or one or more slots.

Aspect 46: The method of any of aspects 33 through 45, where the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

Aspect 47: A method for wireless communications at a base station, including: receiving, from a user equipment (UE), a UE capability to receive a first portion of a TRS and a second portion of a TRS, the first portion and the second portion associated with a TRS pattern; selecting the TRS pattern including the first portion and the second portion for one or more TRSs based on receiving the UE capability; transmitting, to the UE, an indication of the TRS pattern; and transmitting the one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.

Aspect 48: The method of aspect 47, further including: receiving a request for the second portion of the TRS pattern from the UE based on a high speed of the UE.

Aspect 49: The method of aspect 47 or 48, where the indication of the TRS pattern corresponds to an index of a table of patterns configured at the UE.

Aspect 50: The method of any of aspects 47 through 49, further including: transmitting a MAC-CE to the UE indicating the table of patterns from one or more tables of patterns.

Aspect 51: The method of any of aspects 47 through 50, further including: transmitting RRC signaling to the UE configuring the table of patterns.

Aspect 52: The method of any of aspects 47 through 51, where the indication of the TRS pattern is transmitted via DCI.

Aspect 53: The method of any of aspects 47 through 52, where transmitting the indication of the TRS pattern includes: transmitting DCI allocating an aperiodic resource for the one or more TRSs.

Aspect 54: The method of any of aspects 47 through 53, further including: transmitting an indication of a triggering state from the base station via DCI or a MAC-CE, where the TRS pattern is based on the triggering state.

Aspect 55: The method of any of aspects 47 through 54, where the first portion of the TRS pattern includes a four symbol gap between TRSs, and the first portion and the second portion of the TRS pattern include a two symbol gap between at least two TRSs.

Aspect 56: The method of any of aspects 47 through 55, where a TRS of the second portion of the TRS pattern is between TRSs of the first portion, before the TRSs of the first portion, or after the TRSs of the first portion.

Aspect 57: The method of any of aspects 47 through 56, where the TRS pattern spans a slot or one or more slots.

Aspect 58: The method of any of aspects 47 through 57, where the first portion of the TRS pattern spans a TRS bandwidth, and the second portion of the TRS pattern spans a subset of the TRS bandwidth.

Aspect 59: The method of any of aspects 47 through 58, where the UE is a first UE, further including: transmitting the indication of the TRS pattern to a second UE that is incapable of receiving the second portion of the TRS pattern; and scheduling a downlink shared channel resource for the second UE, where the downlink shared channel resource at least partially overlaps with the second portion of the TRS in time, frequency, antenna port, or any combination thereof, based on a modulation and coding scheme of the second UE being low.

Aspect 60: The method of any of aspects 47 through 59, where the UE is a first UE, further including: scheduling a second UE for a downlink shared channel during a slot including the one or more TRSs, where the second UE is incapable of receiving the second portion of the TRS pattern; and transmitting the indication of the TRS pattern to the second UE, where the indication configures the second UE for a zero-power channel state information reference signal during the second portion of the TRS pattern.

Aspect 61: An apparatus for wireless communication including at least one means for performing a method of any one of aspects 33 through 46.

Aspect 62: An apparatus for wireless communication including a processor; and memory coupled to the processor, the processor and memory configured to perform a method of any one of aspects 33 through 46.

Aspect 63: A non-transitory computer-readable medium storing code for wireless communication including a processor, memory in electronic communication with the processor, and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any one of aspects 47 through 60.

Aspect 64: An apparatus for wireless communication including at least one means for performing a method of any one of aspects 47 through 60.

Aspect 65: An apparatus for wireless communication including a processor; and memory coupled to the processor, the processor and memory configured to perform a method of any one of aspects 33 through 46.

Aspect 66: A non-transitory computer-readable medium storing code for wireless communication including a processor, memory in electronic communication with the processor, and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any one of aspects 47 through 60.