Measurement gap and scheduling

Aspects are provided which allow a UE to trigger initiation of an SR procedure in response to a decrease in an amount of received data or uplink grants following a measurement gap. The UE receives data from a first base station. The UE performs a measurement of a downlink signal from a second base station based on a measurement configuration. The UE transmits a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed. As a result, inefficient data stalls caused by erroneous DRX determinations by a base station may be avoided.

BACKGROUND

Technical Field

The present disclosure generally relates to communication systems, and more particularly, to a wireless communication system between a user equipment (UE) and a base station.

Introduction

SUMMARY

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The apparatus receives data from a first base station. The apparatus performs a measurement of a downlink signal from a second base station based on a measurement configuration. The apparatus transmits a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed.

DETAILED DESCRIPTION

A base station may perform various radio resource management (RRM) procedures, such as handovers, radio resource control (RRC) reconfigurations, and data scheduling, in response to information provided by a UE. For example, the base station may perform outer loop link adaptation (OLLA) to improve a radio link with the UE in response to channel measurements performed by the UE, hybrid automatic repeat request (HARQ) feedback from the UE, or other information from the UE (e.g. radio link control (RLC) information and upper layer acknowledgments).

With respect to channel measurements, the base station may provide a measurement configuration to the UE (e.g. in an RRC reconfiguration message) that configures the UE to perform and report such measurements. For example, the measurement configuration may include one or more measurement objects indicating the frequency, time location, and subcarrier spacing of reference signals the UE is to measure (e.g. synchronization signal block (SSB), channel state information reference signal (CSI-RS), demodulation reference signal (DMRS), etc.), a reporting configuration for each measurement object (e.g. event triggered reporting or periodic reporting), measurement gaps indicating the time periods during which the UE may perform measurements, and other measurement criteria. Based on the measurement configuration, the UE may report intra-frequency 5G New Radio (NR) measurements, inter-frequency NR measurements, or inter-radio access technology (RAT) measurements of Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (E-UTRA) frequencies (e.g. 4G Long Term Evolution (LTE)) to the base station. For instance, during a configured measurement gap, the UE connected to a serving cell on one frequency and in one RAT may measure a reference signal receive power (RSRP) of a configured reference signal in a neighbor cell on a same frequency, on a different frequency, or in a different RAT, and the UE may report the measurement to the base station when the measurement exceeds a threshold. Based on the measurements, the base station may adapt its scheduling grants to the UE or perform other RRM procedures.

Additionally, the measurement configuration may also support multi-radio dual connectivity (MR-DC). In MR-DC, two different nodes or base stations may provide resources and data to the UE, including a master node (MN) and a secondary node (SN). One type of MR-DC is E-UTRA-NR dual connectivity (EN-DC), in which the MN is an Evolved Node B (eNB in LTE) and the SN is a gNodeB (gNB in NR). Generally, in EN-DC, the eNB/MN sends RRC messages to the UE including the measurement configuration, while the gNB/SN sends data to the UE. The eNB/MN may also send data to the UE. The measurement configuration configured by the eNB/MN may include similar information as described above (e.g. measurement objects, reporting configuration, measurement gaps, and other criteria), and the UE may similarly report intra-frequency, inter-frequency, or inter-RAT measurements to the eNB/MN or gNB/SN based on the measurement configuration. For example, during a configured measurement gap, the UE connected to a serving eNB and gNB in EN-DC may measure an RSRP of a configured reference signal in a neighbor cell, and the UE may report the measurement to the serving eNB or gNB when the measurement exceeds a threshold. Based on the measurements, the eNB/MN or gNB/SN may adapt its scheduling grants to the UE or perform other RRM procedures.

Generally, a UE may not be able to measure a target carrier frequency in a neighbor cell simultaneously while transmitting or receiving on a serving cell. Thus, to enable the UE to perform such measurements, the base station (for example, the eNB/MN in EN-DC) may configure measurement gaps for the UE. During a measurement gap, the UE may retune its antennas to the frequency or RAT of the neighbor cell, perform measurements in the neighbor cell, and then retune its antennas back to the serving cell. The UE may repeat the measurement process periodically during each configured measurement gap.

However, in some cases while a UE is performing measurements during a configured measurement gap, a serving base station may still send scheduling grants to the UE. For example, in EN-DC, a lack of measurement gap coordination may exist between the eNB/MN providing the measurement configuration and the gNB/SN providing scheduling grants for data. As a result, the gNB/SN may transmit scheduling grants to the UE during the measurement gaps. As the UE is unable to receive the grants since the UE has tuned out from the gNB/SN to perform measurements during these periods of time, the UE may not report HARQ feedback to the base station acknowledging (or not acknowledging) the scheduling grants. Consequently, the base station may inaccurately determine from the lack of HARQ feedback that the UE is currently in a discontinuous reception (DRX) mode, and thus the base station may refrain from further transmitting grants for a period of time. Generally in DRX, the UE monitors the radio channel periodically for downlink data during an “on” duration and powers down most of its circuitry to save battery life during an “off” duration, and therefore the base station typically transmits data to the UE during the on duration while refraining from transmitting data to the UE during the off duration to save resources. Accordingly, the base station may refrain from transmitting scheduling grants to the UE for a period of time based on the incorrect assumption that the UE is in the off duration, even though the UE may have completed its measurements, has retuned back to the serving gNB/SN, and is in the on duration during this period of time. Thus, data transmissions to the UE may be inefficiently stalled, resulting in reduced data throughput.

To prevent this data stalling from occurring in such cases, the UE may transmit a scheduling request (SR) to the serving base station after performing a measurement based on the measurement configuration. The SR may inform the serving base station that the UE is not in the DRX off duration and currently has data to transmit to the base station. For example, to initiate the SR procedure, the UE may trigger a buffer status report (BSR) (e.g. a regular BSR) in response to determining a decrease in an amount of data received from the serving base station or in an amount of uplink grants received from the serving base station following a measurement gap. To identify whether such decrease has occurred, the UE may first determine whether a threshold amount of data and/or a threshold amount of uplink grants, e.g. x bytes of data and/or z number of grants, was received from the base station within a threshold amount of time prior to performing the measurement, e.g. y ms before the measurement gap, where x, y, and z are preconfigured thresholds. If so, then the UE may next determine whether the UE tuned to a different frequency, RAT, or cell (relative to a frequency, RAT, or cell of the serving base station) to perform a measurement during the measurement gap. Afterwards, the UE may determine whether another threshold amount of data and/or another threshold amount of uplink grants, e.g. a bytes of data and/or c number of grants, was not received from the base station within another threshold amount of time after performing the measurement, e.g. b ms after the measurement gap, where a, b, and c are preconfigured thresholds and may respectively be the same as or different than x, y, and z. If so, the UE may determine that a decrease in received data or received grants has occurred since the measurement gap, and the UE may transmit SR accordingly to prevent the serving base station from incorrectly determining the UE to be in the DRX off duration. That is, if the UE determines that a threshold amount of data and/or a threshold amount of uplink grants was received within a threshold amount of time prior to the measurement gap, but that the same or a different threshold amount of data and/or uplink grants was not received within a threshold amount of time after the measurement gap (e.g., the thresholds were met before the gap but not after the gap), the UE may conclude that a decrease in received data or received grants has occurred, and thus the UE may transmit the SR in response to this conclusion. Thus, data stalling may be prevented and data throughput may be improved.

Referring again toFIG.1, in certain aspects, the UE104may include a measurement gap component198that is configured to receive data from a first base station, perform a measurement of a downlink signal from a second base station based on a measurement configuration, and transmit a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed.

Although the present disclosure may focus on 5G NR, the concepts and various aspects described herein may be applicable to other similar areas, such as LTE, LTE-Advanced (LTE-A), Code Division Multiple Access (CDMA), Global System for Mobile communications (GSM), or other wireless/radio access technologies.

At least one of the TX processor368, the RX processor356, and the controller/processor359may be configured to perform aspects in connection with measurement gap component198ofFIG.1.

A base station may perform various RRM procedures, such as handovers, RRC reconfigurations, and data scheduling, in response to information provided by a UE. For example, the base station may perform OLLA to improve a radio link with the UE in response to channel measurements performed by the UE, HARQ feedback from the UE, or other information from the UE (e.g. RLC information and upper layer acknowledgments).

With respect to channel measurements, the base station may provide a measurement configuration to the UE (e.g. in an RRC reconfiguration message) that configures the UE to perform and report such measurements. For example, the measurement configuration may include one or more measurement objects indicating the frequency, time location, and subcarrier spacing of reference signals the UE is to measure (e.g. SSB, CSI-RS, DMRS, etc.), a reporting configuration for each measurement object (e.g. event triggered reporting or periodic reporting), measurement gaps indicating the time periods during which the UE may perform measurements, and other measurement criteria. Based on the measurement configuration, the UE may report intra-frequency NR measurements, inter-frequency NR measurements, or inter-RAT measurements of E-UTRA frequencies (e.g. LTE) to the base station. For instance, during a configured measurement gap, the UE connected to a serving cell on one frequency and in one RAT may measure an RSRP of a configured reference signal in a neighbor cell on a same frequency, on a different frequency, or in a different RAT, and the UE may report the measurement to the base station when the measurement exceeds a threshold. Based on the measurements, the base station may adapt its scheduling grants to the UE or perform other RRM procedures.

Additionally, the measurement configuration may also support MR-DC. In MR-DC, two different nodes or base stations may provide resources and data to the UE, including an MN and a SN. One type of MR-DC is EN-DC, in which the MN is an eNB (LTE) and the SN is a gNB (NR). Generally, in EN-DC, the eNB/MN sends RRC messages to the UE including the measurement configuration, while the gNB/SN sends data to the UE. The eNB/MN may also send data to the UE. The measurement configuration configured by the eNB/MN may include similar information as described above (e.g. measurement objects, reporting configuration, measurement gaps, and other criteria), and the UE may similarly report intra-frequency, inter-frequency, or inter-RAT measurements to the eNB/MN or gNB/SN based on the measurement configuration. For example, during a configured measurement gap, the UE connected to a serving eNB and gNB in EN-DC may measure an RSRP of a configured reference signal in a neighbor cell, and the UE may report the measurement to the serving eNB or gNB when the measurement exceeds a threshold. Based on the measurements, the eNB/MN or gNB/SN may adapt its scheduling grants to the UE or perform other RRM procedures.

Generally, a UE may not be able to measure a target carrier frequency in a neighbor cell simultaneously while transmitting or receiving on a serving cell. Thus, to enable the UE to perform such measurements, the base station (for example, the eNB/MN in EN-DC) may configure measurement gaps for the UE. During a measurement gap, the UE may retune its antennas to the frequency or RAT of the neighbor cell, perform measurements in the neighbor cell, and then retune its antennas back to the serving cell. The UE may repeat the measurement process periodically during each configured measurement gap.

FIG.4illustrates an example400of a measurement gap402. When the UE receives a measurement configuration from the base station, the measurement configuration may include a measurement gap configuration indicating a measurement gap length (e.g. 1.5, 3, 3.5, 4, 5.5, 6 ms, etc.), a measurement gap repetition periodicity (e.g. 20, 40, 80, 160 ms, etc.), and other criteria. For instance,FIG.4illustrates an example where the base station configures the UE with a measurement gap length of 4 ms (e.g. 4 subframes) and a measurement repetition periodicity of 40 ms (e.g. occurring after every 4 frames), although different gap lengths and periodicities may be configured in other examples. During each measurement gap402, the UE may perform RF retuning to a different frequency, RAT, or cell, perform measurements, and then perform RF tuning back from the different frequency, RAT, or cell.

However, in some cases while a UE is performing measurements during a configured measurement gap, a serving base station may still send scheduling grants to the UE. For example, in EN-DC, a lack of measurement gap coordination may exist between the eNB/MN providing the measurement configuration and the gNB/SN providing scheduling grants for data. As a result, the gNB/SN may transmit scheduling grants to the UE during the measurement gaps. As the UE is unable to receive the grants since the UE has tuned out from the gNB/SN to perform measurements during these periods of time, the UE may not report HARQ feedback to the base station acknowledging (or not acknowledging) the scheduling grants. Consequently, the base station may inaccurately determine from the lack of HARQ feedback that the UE is currently in a DRX mode, and thus the base station may refrain from further transmitting grants for a period of time. Generally in DRX, the UE monitors the radio channel periodically for downlink data during an “on” duration and powers down most of its circuitry to save battery life during an “off” duration, and therefore the base station typically transmits data to the UE during the on duration while refraining from transmitting data to the UE during the off duration to save resources. Accordingly, the base station may refrain from transmitting scheduling grants to the UE for a period of time based on the incorrect assumption that the UE is in the off duration, even though the UE may have completed its measurements, has retuned back to the serving gNB/SN, and is in the on duration during this period of time. Thus, data transmissions to the UE may be inefficiently stalled, resulting in reduced data throughput.

FIG.5illustrates an example500of a UE502in communication with serving base stations in EN-DC, including an eNB504(MN) and a gNB506(SN). The eNB504and gNB506may be in respective serving cells A and B, respectively. The eNB504may provide a measurement configuration to the UE502(e.g. via RRC signaling) to perform intra-frequency, inter-frequency, or inter-RAT measurements of a reference signal from a neighbor base station508in a neighbor cell C. The measurement configuration may include a configured measurement occasion or measurement gap (e.g. measurement gap402) during which the UE502may periodically perform its measurements. At the beginning of the UE's DRX on duration, the gNB506may send reference signals (e.g. CSI-RS) and scheduling grants for downlink data, uplink data, or measurement reports (e.g. CSI reports). However, due to a lack of measurement gap coordination between the eNB504and gNB506, the gNB506may continue to send scheduling grants to the UE502while the UE is performing measurements during measurement gaps. As the UE502does not expect to receive data while performing its measurements, the UE may not send HARQ feedback to gNB506, causing the gNB to incorrectly determine the UE to be in the DRX off duration. As a result, the gNB506may stop transmitting scheduling grants to the UE, resulting in data stalling at least until after the UE experiences an actual DRX off duration and subsequent DRX on duration.

To prevent this data stalling from occurring in such cases, the UE may transmit a SR to the serving base station after performing a measurement based on the measurement configuration. The SR may inform the serving base station that the UE is not in the DRX off duration and currently has data to transmit to the base station. For example, to initiate the SR procedure, the UE may trigger a BSR (e.g. a regular BSR) in response to determining a decrease in an amount of data received from the serving base station and/or in an amount of uplink grants received from the serving base station following a measurement gap. To identify whether such decrease has occurred, the UE may first determine whether a threshold amount of data and/or a threshold amount of uplink grants, e.g. x bytes of data and/or z number of grants, was received from the base station within a threshold amount of time prior to performing the measurement, e.g. y ms before the measurement gap, where x, y, and z are preconfigured thresholds. For example, referring toFIGS.4and5, the UE502may determine whether at least 20 KB of data (or some other threshold amount of data) or at least 3 uplink grants (or some other threshold number of grants) was received from gNB506(or eNB504) in the last 5 ms (or some other threshold amount of time) before one of the measurement gaps402. If so, then the UE may next determine whether the UE tuned to a different frequency, RAT, or cell (relative to a frequency, RAT, or cell of the serving base station) to perform a measurement during the measurement gap. For example, referring toFIGS.4and5, the UE502may determine from the measurement configuration that the UE measured RSRP of an SSB, CSI-RS, or some other downlink signal of neighbor base station508during the same one of the measurement gaps402. If so, then the UE may determine whether another threshold amount of data and/or another threshold amount of uplink grants, e.g. a bytes of data and/or c number of grants, was not received from the base station within another threshold amount of time after performing the measurement, e.g. b ms after the measurement gap, where a, b, and c are preconfigured thresholds and may respectively be the same as or different than x, y, and z. For example, referring toFIGS.4and5, the UE502may determine whether at least 20 KB of data (or some other threshold amount of data) or at least 3 uplink grants (or some other threshold number of grants) was not received from eNB504or gNB506in the last 5 ms (or some other threshold amount of time) after measurement gap402. If so, the UE may determine that a decrease in received data or received grants has occurred since the measurement gap, and the UE may transmit SR accordingly to prevent the serving base station from incorrectly determining the UE to be in the DRX off duration.

For example, if the UE has not received an uplink grant to transmit data after the measurement gap, the UE may trigger the regular BSR and initiate a SR procedure. For instance, the UE may periodically transmit SR on PUCCH a configured number of times until the UE receives an uplink grant from the serving base station (e.g. eNB504or gNB506), in response to which the UE may transmit the BSR (e.g. in a MAC-CE). As a result of the SR (or BSR), the serving base station may determine that the UE is not in a DRX mode or DRX off duration and that the UE is thus able to decode scheduling grants and data, thereby preventing data stalling and improving data throughput.

FIG.6illustrates an example600of a call flow between a UE602and base stations604,606,608. Referring toFIG.5, UE602may correspond to UE502, base station604may correspond to eNB504in serving cell A, base station606may correspond to gNB506in serving cell B, and base station608may correspond to neighbor base station508in neighbor cell C. Alternatively, in some cases, base station604may correspond to gNB506in serving cell B, and base station606may correspond to eNB504in serving cell A. The UE602may initially receive a measurement configuration610from base station604configuring the UE to perform measurements of a downlink signal612from base station608. The measurement configuration610may also include a measurement gap613indicating the period of time during which the UE is to perform the measurements (e.g. measurement gap402). Afterwards, the UE may receive data614and uplink grants615from base station606, as well as reference signals (e.g. CSI-RS) and scheduling grants for downlink data and CSI reports. Although not shown, the UE may similarly receive data614and uplink grants615from base station604.

Next, at616, the UE may determine that a threshold amount of data (e.g. data614) or a threshold amount of uplink grants (e.g. uplink grants615) is received from a serving base station within a threshold amount of time. For example, the UE602may determine that at least 20 KB of data (or some other number) or at least 3 uplink grants (or some other number) was received from base station606(or base station604) in the last 5 ms (or some other number) before measurement gap613. Then, at618, the UE may perform a measurement of a downlink signal from a neighbor base station based on the measurement configuration. For example, the UE602may measure an RSRP, a reference signal receive quality (RSRQ), or a signal-to-noise ratio (SNR) of downlink signal612(e.g. SSB, CSI-RS, DMRS, etc.) from base station608during measurement gap613, as configured in measurement configuration610. After performing the measurement, then at620, the UE may determine that another threshold amount of data or another threshold amount of uplink grants is not received from the serving base station within another threshold amount of time. For example, the UE602may determine that at least 20 KB of data (or some other number) or at least 3 uplink grants (or some other number) was not received from base station606(or base station604) in the last 5 ms (or some other number) after measurement gap613. For instance, as illustrated inFIG.6, the UE may determine that no data or uplink grants were received from base station606or604after performing the measurement at618.

Accordingly, at622, the UE may identify a decrease in amount of received downlink data or uplink grants from the serving base station based on the determinations at616and620, and consequently the UE may transmit a scheduling request624to base station606(or base station604) to inform the serving base station that the UE has data available to transmit. As a result, the base station606(or604) may send an uplink grant626to the UE602including configured resources for the uplink transmission, and the UE may subsequently send a BSR628to the corresponding base station in the configured resources. Thus, a degradation in data throughput may be avoided. Additionally, while the example ofFIG.6illustrates the determination at616being performed before the measurement at618, in other examples, the UE may perform the determination at616after performing the measurement at618.

Moreover, whileFIG.6illustrates the example where the UE transmits SR in response to identifying that a decrease has occurred in either an amount of received downlink data or an amount of uplink grants, the UE may alternatively transmit SR in response to identifying that a decrease has occurred in both an amount of received data and an amount of uplink grants. In such case, the UE may perform the determinations at616and620separately for each amount (i.e. data and uplink grants) based on same or different threshold amounts of data, uplink grants, or time. For instance, the UE may transmit SR in response to identifying that at least 20 KB of data (or some other number) was not received from base station606(or base station604) in the last 5 ms (or some other number) after measurement gap613, and in response to further identifying that at least 3 uplink grants were not received from base station606(or base station604) in the last 5 ms (or some other number) after measurement gap613. Thus, SR may be transmitted in response to decreases in received downlink data, decreases in received uplink grants, or a combination of the two.

FIG.7is a flowchart700of a method of wireless communication. The method may be performed by a UE (e.g., the UE104,350,502,602; the apparatus802). Optional aspects are illustrated in dashed lines. The method allows a UE to trigger initiation of an SR procedure in response to a decrease in at least one of an amount of received downlink data or uplink grants following a measurement gap in order to avoid inefficient data stalls caused by erroneous DRX determinations by a base station.

At702, the UE receives data from a first base station. For example,702may be performed by data component840. For instance, referring toFIG.6, the UE602may receive data614from base station606. The UE350,602may receive the data614from base station310,606, for example, according to the following example process: the UE may obtain the data using one or more of the antennas352, the UE may demodulate the obtained data (e.g., in RX processor356), and the UE may decode the demodulated data (e.g., in the controller/processor359). The UE may also store the decoded data in memory360.

At704, the UE may determine, before performing a measurement of a downlink signal from a second base station, that a threshold amount of data is received from the first base station within a threshold length of time. Alternatively or additionally, the UE may determine at704, before performing the measurement, that a threshold number of uplink grants is received from the first base station within a threshold length of time. Thus, at704, the UE may determine, before performing the measurement, that at least one of a threshold amount of data or a threshold number of uplink grants is received from the first base station within a threshold length of time. For example,704may be performed by first determination component842. For instance, referring toFIG.6, the UE602may determine at616, before performing a measurement at618of downlink signal612from base station608, that a threshold amount of data such as x bytes of data and/or a threshold number of uplink grants such as z number of grants is received from base station606within a threshold length of time such as y ms before measurement gap613. The thresholds x and z may be the same as or different from each other. In an example process of making the determination at616, the UE602(e.g., the controller/processor359of UE350) may count, within a configured (threshold) period of time y ms (prior to measuring downlink signal612), a number of bytes of data received from base station606and/or a number of uplink grants received from base station606, the UE may compare the counted number of bytes and/or number of uplink grants with a threshold amount of data (x bytes) and/or a threshold number of uplink grants (z grants), respectively, and the UE may identify that the counted number of bytes and/or number of uplink grants at least meet the threshold amount of data and/or threshold number of uplink grants, respectively (e.g., the number of counted bytes is at least x bytes and/or the number of counted grants is at least z grants).

At706, the UE performs the measurement of the downlink signal from the second base station based on a measurement configuration. For example,706may be performed by measurement component844. For instance, referring toFIG.6, the UE602may perform the measurement at618of downlink signal612from base station608. In an example process of performing the measurement at618, the UE (e.g., the controller/processor359of UE350) may receive the downlink signal from base station608(e.g., using one or more antennas352and following demodulation and decoding of the downlink signal), and the UE may obtain an RSRP, a RSRQ, or a SNR of the downlink signal612. Moreover, the measurement may be performed at618based on the measurement configuration610. For instance, the measurement configuration may include one or more measurement objects indicating the frequency, time location, and subcarrier spacing of reference signal(s) (e.g., downlink signal612) the UE is to measure (e.g. SSB, CSI-RS, DMRS, etc.) from base station608, and the UE may perform the measurement of the reference signal(s) indicated in the configured measurement object(s). The measurement configuration may be received from a third base station in dual connectivity with the first base station (e.g. base station604such as illustrated inFIG.6). Alternatively, the measurement configuration may be received from the first base station (e.g. base station606) in another example. Furthermore, the measurement configuration may indicate a measurement gap (e.g. measurement gap613), and the measurement may be performed at618during the measurement gap. For instance, the UE may measure the reference signal(s) indicated in the configured measurement object(s) during the measurement gap402indicated in the measurement configuration.

At708, the UE may determine, after performing the measurement, that another threshold amount of data is not received from the first base station within another threshold length of time. Alternatively or additionally, the UE may determine at708, after performing the measurement, that another threshold number of uplink grants is not received from the first base station within another threshold length of time. Thus, at708, the UE may determine, after performing the measurement, that at least one of another threshold amount of data or another threshold number of uplink grants is not received from the first base station within another threshold length of time. For example,708may be performed by second determination component846. The another threshold amount of time may be the same as, or different from, the threshold amount of time referenced at704, the another threshold number of uplink grants may be the same as, or different from, the threshold number of uplink grants referenced at704, and the another threshold length of time may be the same as, or different from, the threshold length of time referenced at704. For instance, referring toFIG.6, the UE602may determine at620, after performing the measurement at618, that another threshold amount of data such as a bytes of data or another threshold number of uplink grants such as c number of uplink grants is not received from base station606within another threshold length of time such as b ms after measurement gap613. In an example process of making the determination at620, the UE602(e.g., the controller/processor359of UE350) may count, within a configured (threshold) period of time b ms (after measuring downlink signal612), a number of bytes of data received from base station606and/or a number of uplink grants received from base station606, the UE may compare the counted number of bytes and/or number of uplink grants with a threshold amount of data (a bytes) and/or a threshold number of uplink grants (c grants), respectively, and the UE may identify that the counted number of bytes and/or number of uplink grants do not meet the threshold amount of data and/or threshold number of uplink grants, respectively (e.g., the number of counted bytes is less than a bytes and/or the number of counted grants is less than c grants). The thresholds a and c may be the same as or different from each other, the thresholds a and x may be the same as or different from each other, the thresholds c and z may be the same as or different from each other, and the thresholds b and y may be the same as or different from each other.

At710, the UE may identify a decrease in an amount of received downlink data based on the determinations at704and708. Alternatively or additionally, the UE may identify at710a decrease in an amount of received grants to transmit uplink data based on the determinations at704and708. Thus, at710, the UE may identify a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data based on the determinations at704and708. For example,710may be performed by identification component848. For instance, referring toFIG.6, the UE602may identify at622a decrease in an amount of received downlink data since measurement gap613based on the determinations at616and620. Alternatively or additionally, the UE602may identify at622a decrease in an amount of received grants to transmit uplink data since measurement gap613based on the determinations at616and620. In an example process of making the identification at622, the UE (e.g., the controller/processor359of UE) may determine as described above at616that a counted number of received bytes and/or counted number of received uplink grants prior to the measurement gap at least meet the threshold amount of data and/or threshold number of uplink grants, the UE may determine as described above at620that another counted number of received bytes and/or another counted number of received uplink grants after the measurement gap do not meet the threshold amount of data and/or threshold number of uplink grants, and the UE may ascertain the decrease has occurred in response to both determinations.

At712, the UE transmits a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed at706. For example,712may be performed by scheduling request component850. The decrease may be the decrease identified at710. For instance, referring toFIG.6, the UE602may transmit scheduling request624to base station606in response to the identification of the decrease at622and after performing the measurement at618. The scheduling request may be transmitted in an absence of receiving a grant after performing the measurement at706. For instance, the UE602may transmit scheduling request624if the UE does not receive an uplink grant from base station606following measurement gap613. The UE350,602may transmit the scheduling request to base station310,606, for example, according to the following example process: the UE may encode the scheduling request (e.g., in the controller/processor359), the UE may modulate the encoded scheduling request (e.g., in the TX processor368), and the UE may send the modulated and encoded scheduling request using one or more of the antennas352.

The scheduling request may also be transmitted at712in response to a BSR being triggered. For instance, referring toFIG.6, the UE may trigger a BSR in response to identifying the decrease at710(and622), after which the UE transmits the scheduling request624at712. Moreover, after transmitting the scheduling request, at714, the UE may receive an uplink grant in response to the scheduling request, and at716, the UE may transmit the BSR in response to the uplink grant. For example,714may be performed by uplink grant component852, and716may be performed by BSR component854. For instance, referring toFIG.6, the UE602may receive uplink grant626in response to the scheduling request624, and the UE may transmit BSR628in response to uplink grant626. The UE350,602may receive the uplink grant from base station310,606, for example, according to the following example process: the UE may obtain the grant using one or more of the antennas352, the UE may demodulate the obtained grant (e.g., in RX processor356), and the UE may decode the demodulated grant (e.g., in the controller/processor359). The UE may also store the decoded grant in memory360. Moreover, the UE350,602may transmit the BSR to base station310,606, for example, according to the following example process: the UE may encode the BSR (e.g., in the controller/processor359), the UE may modulate the encoded BSR (e.g., in the TX processor368), and the UE may send the modulated and encoded BSR using one or more of the antennas352.

In one example, the second base station may be of a different RAT than the first base station. For instance, referring toFIG.6, base station608may an eNB while base station606may be a gNB. In another example, the downlink signal from the second base station may be received on a different frequency than the data received from the first base station. For instance, referring toFIG.6, downlink signal612from base station608may be received on different frequency than data614from base station606. In a further example, the second base station may be in a different cell than the first base station. For instance, referring toFIG.6, base station608may be in a different cell (e.g. neighbor base station508in cell C ofFIG.5) than base station606(e.g. gNB506in cell B ofFIG.5).

FIG.8is a diagram800illustrating an example of a hardware implementation for an apparatus802. The apparatus802is a UE and includes a cellular baseband processor804(also referred to as a modem) coupled to a cellular RF transceiver822and one or more subscriber identity modules (SIM) cards820, an application processor806coupled to a secure digital (SD) card808and a screen810, a Bluetooth module812, a wireless local area network (WLAN) module814, a Global Positioning System (GPS) module816, and a power supply818. The cellular baseband processor804communicates through the cellular RF transceiver822with the UE104and/or BS102/180. The cellular baseband processor804may include a computer-readable medium/memory. The computer-readable medium/memory may be non-transitory. The cellular baseband processor804is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the cellular baseband processor804, causes the cellular baseband processor804to perform the various functions described supra. The computer-readable medium/memory may also be used for storing data that is manipulated by the cellular baseband processor804when executing software. The cellular baseband processor804further includes a reception component830, a communication manager832, and a transmission component834. The communication manager832includes the one or more illustrated components. The components within the communication manager832may be stored in the computer-readable medium/memory and/or configured as hardware within the cellular baseband processor804. The cellular baseband processor804may be a component of the UE350and may include the memory360and/or at least one of the TX processor368, the RX processor356, and the controller/processor359. In one configuration, the apparatus802may be a modem chip and include just the baseband processor804, and in another configuration, the apparatus802may be the entire UE (e.g., see350ofFIG.3) and include the aforediscussed additional modules of the apparatus802.

The communication manager832includes a data component840that is configured to receive data from a first base station, e.g., as described in connection with702. The communication manager832further includes a first determination component842that receives input in the form of data from data component840and is configured to determine, before performing the measurement, that at least one of a threshold amount of data or a threshold number of uplink grants is received from the first base station within a threshold length of time, e.g., as described in connection with704. The communication manager832further includes a measurement component844that is configured to perform a measurement of a downlink signal from a second base station based on a measurement configuration, e.g., as described in connection with706. The communication manager832further includes a second determination component846that receives input in the form of data from data component840and is configured to determine, after performing the measurement, that at least one of another threshold amount of data or another threshold number of uplink grants is not received from the first base station within another threshold length of time, e.g., as described in connection with708. The communication manager832further includes an identification component848that receives input in the form of the determinations from first determination component842and second determination component846and is configured to identify the decrease in the at least one of the amount of the received downlink data or the number of the received grants to transmit the uplink data based on the determinations, e.g., as described in connection with710. The communication manager832further includes a scheduling request component850that receives input in the form of the data from data component840and measurement from measurement component844, as well as the identification from identification component848, and is configured to transmit a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed, e.g., as described in connection with712. The communication manager832further includes an uplink grant component852that is configured to receive an uplink grant in response to the scheduling request, e.g., as described in connection with714. The communication manager832further includes a BSR component854that receives input in the form of the uplink grant from uplink grant component852and is configured to transmit the BSR in response to the uplink grant, e.g., as described in connection with716.

In one configuration, the apparatus802, and in particular the cellular baseband processor804, includes means for receiving data from a first base station, means for performing a measurement of a downlink signal from a second base station based on a measurement configuration, and means for transmitting a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed.

In one configuration, the measurement configuration may be received from the first base station or a third base station in dual connectivity with the first base station.

In one configuration, the scheduling request may be transmitted in an absence of receiving a grant after performing the measurement.

In one configuration, the scheduling request may be transmitted in response to a BSR being triggered. In one configuration, the means for receiving may be further configured to receive an uplink grant in response to the scheduling request, and the means for transmitting may be further configured to transmit the BSR in response to the uplink grant.

In one configuration, the measurement configuration may indicate a measurement gap, and the measurement may be performed during the measurement gap.

In one configuration, the second base station may be of a different RAT than the first base station. In one configuration, the downlink signal from the second base station may be received on a different frequency than the data received from the first base station. In one configuration, the second base station may be in a different cell than the first base station.

In one configuration, the apparatus802, and in particular the cellular baseband processor804, may include means for determining, before performing the measurement, that at least one of a threshold amount of data or a threshold number of uplink grants is received from the first base station within a threshold length of time. The means for determining may be further configured to determine, after performing the measurement, that at least one of another threshold amount of data or another threshold number of uplink grants is not received from the first base station within another threshold length of time. The apparatus802, and in particular the cellular baseband processor804, may also include means for identifying the decrease in the at least one of the amount of the received downlink data or the number of the received grants to transmit the uplink data based on the determinations.

The aforementioned means may be one or more of the aforementioned components of the apparatus802configured to perform the functions recited by the aforementioned means. As described supra, the apparatus802may include the TX Processor368, the RX Processor356, and the controller/processor359. As such, in one configuration, the aforementioned means may be the TX Processor368, the RX Processor356, and the controller/processor359configured to perform the functions recited by the aforementioned means.

Example 1 is a method of wireless communication at a UE, comprising: receiving data from a first base station; performing a measurement of a downlink signal from a second base station based on a measurement configuration; and transmitting a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed.

Example 2 is the method of Example 1, wherein the measurement configuration is received from the first base station or a third base station in dual connectivity with the first base station.

Example 3 is the method of any of Examples 1 and 2, wherein the scheduling request is transmitted in an absence of receiving a grant after performing the measurement.

Example 4 is the method of any of Examples 1 to 3, wherein the scheduling request is transmitted in response to a BSR being triggered.

Example 5 is the method of Example 4, further comprising: receiving an uplink grant in response to the scheduling request; and transmitting the BSR in response to the uplink grant.

Example 6 is the method of any of Examples 1 to 5, wherein the measurement configuration indicates a measurement gap, and wherein the measurement is performed during the measurement gap.

Example 7 is the method of any of Examples 1 to 6, wherein the second base station is of a different RAT than the first base station.

Example 8 is the method of any of Examples 1 to 7, wherein the downlink signal from the second base station is received on a different frequency than the data received from the first base station.

Example 9 is the method of any of Examples 1 to 8, wherein the second base station is in a different cell than the first base station.

Example 10 is the method of any of Examples 1 to 9, further comprising: determining, before performing the measurement, that at least one of a threshold amount of data or a threshold number of uplink grants is received from the first base station within a threshold length of time; determining, after performing the measurement, that at least one of another threshold amount of data or another threshold number of uplink grants is not received from the first base station within another threshold length of time; and identifying the decrease in the at least one of the amount of the received downlink data or the number of the received grants to transmit the uplink data based on the determinations.

Example 11 is an apparatus for wireless communication, comprising: a processor; memory coupled with the processor; and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to: receive data from a first base station; perform a measurement of a downlink signal from a second base station based on a measurement configuration; and transmit a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed.

Example 12 is the apparatus of Example 11, wherein the measurement configuration is received from the first base station or a third base station in dual connectivity with the first base station.

Example 13 is the apparatus of any of Examples 11 and 12, wherein the scheduling request is transmitted in an absence of receiving a grant after performing the measurement.

Example 14 is the apparatus of any of Examples 11 to 13, wherein the scheduling request is transmitted in response to a BSR being triggered.

Example 15 is the apparatus of Example 14, wherein the instructions, when executed by the processor, further cause the apparatus to: receive an uplink grant in response to the scheduling request; and transmit the BSR in response to the uplink grant.

Example 16 is the apparatus of any of Examples 11 to 15, wherein the measurement configuration indicates a measurement gap, and wherein the measurement is performed during the measurement gap.

Example 17 is the apparatus of any of Examples 11 to 16, wherein the second base station is of a different RAT than the first base station.

Example 18 is the apparatus of any of Examples 11 to 17, wherein the downlink signal from the second base station is received on a different frequency than the data received from the first base station.

Example 19 is the apparatus of any of Examples 11 to 18, wherein the second base station is in a different cell than the first base station.

Example 20 is the apparatus of any of Examples 11 to 19, wherein the instructions, when executed by the processor, further cause the apparatus to: determine, before performing the measurement, that at least one of a threshold amount of data or a threshold number of uplink grants is received from the first base station within a threshold length of time; determine, after performing the measurement, that at least one of another threshold amount of data or another threshold number of uplink grants is not received from the first base station within another threshold length of time; and identify the decrease in the at least one of the amount of the received downlink data or the number of the received grants to transmit the uplink data based on the determinations.

Example 21 is an apparatus for wireless communication, comprising: means for receiving data from a first base station; means for performing a measurement of a downlink signal from a second base station based on a measurement configuration; and means for transmitting a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed.

Example 22 is the apparatus of Example 21, wherein the measurement configuration is received from the first base station or a third base station in dual connectivity with the first base station.

Example 23 is the apparatus of any of Examples 21 and 22, wherein the scheduling request is transmitted in an absence of receiving a grant after performing the measurement.

Example 24 is the apparatus of any of Examples 21 to 23, wherein the scheduling request is transmitted in response to a BSR being triggered.

Example 25 is the apparatus of Example 24, wherein the means for receiving is further configured to receive an uplink grant in response to the scheduling request; and wherein the means for transmitting is further configured to transmit the BSR in response to the uplink grant.

Example 26 is the apparatus of any of Examples 21 to 25, wherein the measurement configuration indicates a measurement gap, and wherein the measurement is performed during the measurement gap.

Example 27 is the apparatus of any of Examples 21 to 26, wherein the second base station is of a different RAT than the first base station.

Example 28 is the apparatus of any of Examples 21 to 27, wherein the downlink signal from the second base station is received on a different frequency than the data received from the first base station.

Example 29 is the apparatus of any of Examples 21 to 28, wherein the second base station is in a different cell than the first base station.

Example 30 is the apparatus of any of Examples 21 to 29, further comprising: means for determining, before performing the measurement, that at least one of a threshold amount of data or a threshold number of uplink grants is received from the first base station within a threshold length of time; wherein the means for determining is further configured to determine, after performing the measurement, that at least one of another threshold amount of data or another threshold number of uplink grants is not received from the first base station within another threshold length of time; and means for identifying the decrease in the at least one of the amount of the received downlink data or the number of the received grants to transmit the uplink data based on the determinations.

Example 31 is a computer-readable medium storing computer executable code, the code when executed by a processor cause the processor to: receive data from a first base station; perform a measurement of a downlink signal from a second base station based on a measurement configuration; and transmit a scheduling request in response to a decrease in at least one of an amount of received downlink data or a number of received grants to transmit uplink data after the measurement is performed.