CARRIER PREFERENCE MEASUREMENT AND INDICATION

In a carrier aggregation or EN-DC scenario, there exist multiple different conditions based on which UE would benefit from a higher or lower grant ratio on a specific carrier as opposed to other carriers. There are a number of criteria based on which UE may select a preferred carrier for uplink grant reception. Some example criteria include self-jamming conditions, thermal constraints, and inter-RAT interference. These and other criteria may form a basis for identifying preferred carriers, non-preferred carriers, or ranking carriers. Various embodiments described provide techniques for a UE to indicate preferred and non-preferred carriers to a serving base station. A serving base station, in turn, can make use of the indication to adjust the ratio at which uplink transmissions are scheduled on these carriers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Indian Application No. 201941007896, filed on Feb. 28, 2019, entitled “CARRIER PREFERENCE MEASUREMENT AND INDICATION,” which is hereby expressly incorporated by reference herein.

BACKGROUND

Technical Field

The present disclosure relates generally to communication systems, and more particularly, to carrier allocation of carriers for transmissions in multi-carrier scenarios.

INTRODUCTION

Multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR).

5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT)), and other requirements. Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology.

These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

BRIEF 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 may measure carrier quality on a plurality of carriers, identify a first carrier from the plurality of carriers. The first carrier may correspond to a first measured carrier quality. The apparatus may send an uplink transmission to a base station, the uplink transmission including a first carrier indicator corresponding to the first carrier, and receive an uplink grant from the base station based on the uplink transmission. The first measured carrier quality may be a highest measured carrier quality or lowest measured carrier quality.

In another embodiment, the apparatus may also identify a second carrier from the plurality of carriers, the second carrier may correspond to a second measured carrier quality. Additionally, the uplink transmission may include a second carrier indicator corresponding to the second carrier. The first measured carrier quality may be a highest measured carrier quality, and the second measured carrier quality may be a lowest measured carrier quality. The apparatus may also receive a downlink transmission from the base station including a DTX configuration for at least one of the first carrier and the second carrier in response to the uplink transmission.

In one embodiment, the uplink transmission may include a buffer status report (BSR). The apparatus may receive an indication from the base station of a BSR format, where the BSR format includes a first carrier indicator field and a second carrier indicator field. In another embodiment, the uplink transmission may include a RRC transmission. The RRC transmission may include the first carrier indicator and the second carrier indicator. The RRC transmission may include a ranked list of carrier indicators including the first carrier indicator and the second carrier indicator. In yet another embodiment, the uplink transmission may include a Medium Access Control (MAC) control element (CE), the MAC CE including the first carrier indicator and the second carrier indicator.

In one embodiment. the measuring of the carrier quality may include measuring self-interference within the UE. The self-interference may correspond to interference from uplink carrier transmission by the UE to one or more downlink carriers. The self-interference may correspond to a delta to an SNR caused by the self-interference. Additionally, the first carrier may correspond to an uplink carrier that causes the least amount of measurable self-interference.

In another embodiment, the measuring of the carrier quality may include determining a thermal metric associated with transmission on one or more uplink carriers. The thermal metric may be based a transmit power and/or a thermal measurement associated with transmission on the one or more uplink carriers. The first carrier may correspond to an uplink carrier that is associated with a transmit chain having the lowest thermal metric. The second carrier may correspond to an uplink carrier associated with a transmit chain having the highest thermal metric.

In yet another embodiment, the apparatus may be associated with a RAT, and the carrier quality is based on an interference metric associated non-WWAN communications.

In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a base station. The apparatus may receive an uplink transmission from a user equipment (UE), the uplink transmission may include a first carrier indicator. The first carrier indicator may correspond to a first carrier quality for a first carrier. The apparatus may also schedule uplink transmissions based on the first carrier indicator, and transmit an uplink grant from the base station based on the uplink transmission. The first carrier quality may be a highest carrier quality or a lowest carrier quality. Scheduling uplink transmissions may include adjusting a rate of uplink grants scheduled on the first carrier.

In an embodiment, the uplink transmission may include a second carrier indicator corresponding to a second carrier and a second carrier quality, and the first carrier quality may be a highest carrier quality, and the second carrier quality may be a lowest carrier quality. Additionally, the apparatus may transmit a DTX configuration for at least one of the first carrier and the second carrier based on the first carrier indicator and the second carrier indicator.

In one embodiment, the uplink transmission may be a buffer status report (BSR). The apparatus may transmit an indication of a BSR format, and the BSR format may include a first carrier indicator field and a second carrier indicator field. In another embodiment, the uplink transmission may include an RCC transmission or a Medium Access Control (MAC) control element (CE), The MAC CE may include the first carrier indicator and the second carrier indicator.

DETAILED DESCRIPTION

In a carrier aggregation or EN-DC scenario, there exist multiple different conditions based on which UE would benefit from a higher or lower grant ratio on a specific carrier as opposed to other carriers. For example, the UE would benefit from indicating a preferred (or non-preferred) carrier to the serving base station. The base station, in turn, could adjust the rate at which uplink grants for the preferred (or non-preferred) carrier is provided to the UE. Furthermore, the preferred (and non-preferred) carrier for a UE may change dynamically based on changing radio conditions.

There are a number of criteria based on which UE may select a preferred carrier for uplink grant reception. Some example criteria explained below include self-jamming conditions, thermal constraints, and inter-RAT interference. These are not the only criteria envisioned as possible bases for identifying preferred carriers, non-preferred carriers, or ranking carriers. Various embodiments described below provide techniques for a UE to indicate preferred and non-preferred carriers to a serving base station. A serving base station, in turn, can make use of the indication to adjust the ratio at which uplink transmissions are scheduled on these carriers.

Certain UEs104may communicate with each other using device-to-device (D2D) communication link192. The D2D communication link192may use the DL/UL WWAN spectrum. The D2D communication link192may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR. The wireless communications system may further include a Wi-Fi access point (AP)150in communication with Wi-Fi stations (STAs)152via communication links154in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs152/AP150may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

Referring again toFIG. 1, in certain aspects, the UE104may be configured to communicate preferred and non-preferred carriers to base station102. Base station102may be configured to schedule uplink transmissions for UE104based on the preferred and non-preferred carriers.

At the UE250, each receiver254RX receives a signal through its respective antenna252. Each receiver254RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor256. The TX processor268and the RX processor256implement layer1functionality associated with various signal processing functions. The RX processor256may perform spatial processing on the information to recover any spatial streams destined for the UE250. If multiple spatial streams are destined for the UE250, they may be combined by the RX processor256into a single OFDM symbol stream. The RX processor256then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station210. These soft decisions may be based on channel estimates computed by the channel estimator258. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station210on the physical channel. The data and control signals are then provided to the controller/processor259, which implements layer2and layer2functionality.

The controller/processor259can be associated with a memory260that stores program codes and data. The memory260may be referred to as a computer-readable medium. In the UL, the controller/processor259provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC160. The controller/processor259is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Channel estimates derived by a channel estimator258from a reference signal or feedback transmitted by the base station210may be used by the TX processor268to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor268may be provided to different antenna252via separate transmitters254TX. Each transmitter254TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station210in a manner similar to that described in connection with the receiver function at the UE250. Each receiver218RX receives a signal through its respective antenna220. Each receiver218RX recovers information modulated onto an RF carrier and provides the information to a RX processor270.

The controller/processor275can be associated with a memory276that stores program codes and data. The memory276may be referred to as a computer-readable medium. In the UL, the controller/processor275provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE250. IP packets from the controller/processor275may be provided to the EPC160. The controller/processor275is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Various wireless communication technologies may have a different frame structure and/or different channels. A frame may be divided into multiple (e.g.,10) equally sized subframes. Each subframe may include multiple consecutive time slots (based on the type of numerology). A resource grid may be used to represent time slots, each time slot may include one or more time concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)). The resource grid is divided into multiple resource elements (REs). For a normal cyclic prefix, an RB may contain consecutive subcarriers in the frequency domain and consecutive symbols. The number of bits carried by each RE depends on the modulation scheme.

Some of the REs may carry reference (pilot) signals (RS) for downlink channel estimation at the UE. These RS may include cell-specific reference signals (CRS) (also sometimes called common RS), UE-specific reference signals (UE-RS), and channel state information reference signals (CSI-RS).

Various channels may exist within a DL subframe. The PDCCH carries downlink control information (DCI) within one or more control channel elements (CCEs), each CCE including multiple RE groups (REGs), each REG including a number of consecutive REs in an OFDM symbol. A UE may be configured with a UE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The physical hybrid automatic repeat request (ARQ) (HARQ) indicator channel (PHICH) carries the HARQ indicator (HI) that indicates HARQ acknowledgement (ACK)/negative ACK (NACK) feedback based on the success of decoding a physical uplink shared channel (PUSCH). A primary synchronization signal (PSS) may serve to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) that is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI). Based on the PCI, the UE can determine the locations of the downlink RS. A physical broadcast channel (PBCH), carries a master information block (MIB). The PBCH may be logically grouped with the PSS and SSS to form a synchronization signal (SS) block. The MIB provides system configuration information, including a number of RBs in the DL system bandwidth, a PHICH configuration, and a system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs), and paging messages.

Uplink subframes may include REs that carry demodulation reference signals (DM-RS) for channel estimation at the base station. The UE may additionally transmit sounding reference signals (SRS) in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

A physical random access channel (PRACH) may be within one or more subframes within a frame based on the PRACH configuration. The PRACH may include consecutive RB pairs within a subframe. The PRACH allows the UE to perform initial system access and achieve UL synchronization. A physical uplink control channel (PUCCH) may be located on edges of the UL system bandwidth. The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and HARQ ACK/NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and/or UCI.

To obtain an uplink grant from a base station, a UE sends an SR to the base station, e.g., following a random access procedure. In response to the SR, the network may allocate a minimal grant for the UE to send a BSR. The BSR indicates how much buffered data is pending uplink transmission at the UE. The BSR indicates the amount of buffered data using different quantized granularities (e.g., using an index). In response to the BSR, the base station may determine and transmit a suitable grant of uplink resources to the UE.

5G NR supports different types of carrier aggregation. Carrier aggregation is supported within frequency range 1 (FR1) (e.g., sub 6 GHz), within frequency range 2 (FR2) (e.g., mmWave), or as a combination of FR1and FR2(e.g., carrier aggregation with Sub 6 Ghz and mmWave carriers). Furthermore, 5G NR also supports EN-DC (EUTRA-NR Dual Connectivity) with at least one carrier on an LTE RAT and at least one carrier on a 5G NR RAT.

With respect to carrier aggregation, the BSR presents a limitation, as buffered data is not indicated per carrier, but as a single value per UE. Accordingly, the UE can indicate the amount of total data pending uplink transmission, but there is no mechanism to identify a preferred carrier from the UE side for the pending data. As such, a UE has no mechanism to specify a carrier on which it would prefer to receive a grant. Instead, the network selects to provide a grant on any of the active carriers.

Most networks employ a combination of CQI reporting from multiple carriers, load balancing, and other scheduling algorithms to determine the carrier on which to provide an uplink grant to the user or the proportions in which grants are distributed across multiple carriers. However, there exist multiple different scenarios and conditions based on which UE would benefit from a higher or lower grant ratio on a specific carrier as opposed to other carriers. In an ideal scenario, the UE could indicate a preferred (or non-preferred) carrier to the serving base station. The base station, in turn, could adjust the rate at which uplink grants for the preferred (or non-preferred) carrier are provided to the UE. Furthermore, the preferred (or non-preferred) carrier for a UE may change dynamically based on radio conditions.

There are a number of criteria based on which UE may prefer a specific carrier for uplink grant reception. Some example criteria explained below include self-jamming conditions, thermal constraints, and inter-RAT interference. These are not the only criteria envisioned as possible bases for identifying preferred carriers, non-preferred carriers, or ranking carriers. The detailed description set forth below in connection with these criteria is not intended to represent the only basis in which the invention may be practiced. The detailed description includes example criteria to provide a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that other criteria may be applied within the scope of the invention.

A first example criterion for identifying preferred carriers, non-preferred carriers, or ranking carriers includes self-jamming and similar interference conditions. In carrier aggregation or EN-DC scenarios, multiple carriers may be actively transmitting or receiving transmission on multiple transceivers. Transmission from one or more uplink carriers could cause self-interference to one of the active downlink carriers. The extent of the self-interference may depend on the in-device isolation between an aggressor transmitter and a victim receiver. The in-device isolation may refer to, for example, the extent to which harmonic or inter-modulation interference from an aggressor transmitter impacts a victim receiver.

In this example, the active uplink carrier causing the least interference to any active receiver would be a preferred carrier and any active uplink carrier which causes the most interference to any active receiver would be the non-preferred carrier. Where there is more than one aggressor transmitter, identifying the preferred (or non-preferred) carrier includes quantifying the interference or self-jamming that is caused to the respective receivers to a metric. This metric may be, for example, SNR-based. A preferred uplink carrier would be the uplink carrier associated with an aggressor transmitter causing the lowest magnitude of self-interference to any victim receiver, subject to a priority metric of the victim. For example, the measurement ranking of the uplink carrier may be based on a magnitude of interference caused to each victim receiver adjusted based on the properties of the receiver. The properties of the receiver may include whether the receiver is operating on a primary carrier or a secondary carrier, whether the victim receiver is idle or associated with a voice session. For example, each victim receiver may be given a priority indicator—a voice receiver has a higher priority than idle receiver for mobile terminated paging, which in turn has a higher priority than data receiver. The magnitude of the interference may be determined, for example, based on a delta between SNR under normal conditions and SNR under self-jamming or interference conditions.

A second example criterion for identifying preferred carriers, non-preferred carrier, or ranking carriers includes thermal constraints. Thermal constraint handling is one of the major concerns in 5G. In a scenario with multiple active uplink carriers, different uplink carriers may be active on different power amplifiers (PA) (for Sub 6 GHz) or different beamers/phasors (for mmW). A thermal (e.g., temperature) metric of each carrier may serve to determine the carrier contributing the most and least to the overall system thermal conditions. The thermal metric may be based on a thermistor reading from different phasors or PAs in a device. For example, a carrier associated with a highest transmit power and thermistor reading may have a greater impact on the overall temperature of the system and would correspond to a non-preferred carrier. Similarly, the carrier with the lowest thermal contribution to the device temperature would be the most preferred carrier. By reducing the ratio of uplink grants on the non-preferred carrier and increasing the ratio of uplink grants on the most preferred carrier, the system could improve the duty cycle of the transmitter components (e.g., PA, phasors, beamers) by allowing them sufficient time to cool down and thereby controlling the temperature of the device.

In an embodiment, the thermal constraints may be determined based on a comparison of active PA thermal readings and average PA thermal readings. For each carrier, the device may track the average transmit power and thermal readings for a last N subframes, and compare a current thermistor reading for active PA/beamer with the average reading. The carrier associated with the PA/phasors with the highest thermistor reading relative to the average reading (beyond a hysteresis) may correspond to a non-preferred carrier (where the hysteresis serves to prevent minor temperature variation from arbitrarily impacting the carrier preference). In response to the preferred carrier indication, the network can respond by providing a thinner grant ratio on the indicated carrier, thereby allowing the PA to go to a lower power mode and cool down.

A third example criterion for identifying preferred carriers, non-preferred carriers, or ranking carriers includes jamming of non-WAN communications (e.g., GNSS). There are scenarios in which the active carrier transmission on 5G NR may jam non-WAN technologies. For example, jamming of GNSS reception is a common scenario.

The present solution for GNSS jamming is to blank GNSS transmissions to the UE when the aggressor is active or perform a power back-off of the aggressor transmission. “Blanking” refers to the practice of modifying the active receiver side such that up to 80% of GNSS subframes are received while there is no active aggressor in the system. However, this extends the sampling period of the GNSS receiver. These solutions suffer from different limitations. For example, with blanking, if an aggressor transmitter is continuously active, excessive blanking may cause GNSS decode failures and poor position fixes. Similarly, power back-off to the aggressor transmit power can cause RLF on cell edge scenarios or power headroom reduction. Both of these limitations can be overcome by indicating a preferred carrier, which is not an aggressor to the active GNSS, and indicating any active aggressor to the GNSS as the non-preferred carrier. Such an approach allocates the thinnest grant ratio to the non-preferred carrier (GNSS aggressor in this example), and thereby allows sufficient non-jamming time to GNSS to perform decodes.

The UE may benefit from a mechanism to indicate a carrier preference to the base station. In one example, an enhanced BSR format may be added that includes fields for signaling one or more carriers to the base station. The base station may indicate to use this enhanced BSR format by providing the UE with a corresponding LCID value.FIG. 3illustrates a table300of LCID values supported by 5G NR. At present, 5G NR supports LCID values for various BSR formats (e.g., short BSR, long BSR, short truncated BSR, long truncated BSR, and padding BSR). The LCID table300includes reserved values305to support future LCID values. Accordingly, one or more new BSR formats may be associated with a reserved LCID value. For example, a new enhanced BSR associated with LCID value33may be added, which includes support for transmission of one or more carrier ID values.

In one example, a new enhanced BSR format may include an additional octet that is defined to include two 4-bit carrier ID values.FIG. 4illustrates an example BSR format400that includes bit indicators for logical channel groups (LCGs)0-7, an octet415for supporting two 4-bit carrier IDs405,410, and Octets2to m+1 (where m<8) for indicating buffer sizes1to m corresponding to the LCG's indicated as present in Octet1of the BSR. Buffer sizes1to m correspond to index values associated with corresponding buffer sizes of pending uplink data for each of LCG0-7indicated as present in Octet1of the BSR. The 4 least significant bits410may specify a preferred carrier ID, and the 4 most significant bits405may specify the non-preferred carrier ID. The 4-bit values allow for 16 possible carrier IDs each. In a variation of the example, to support up to 32 carriers, an entire or portion of a first octet can be reserved to indicate a preferred carrier ID, and an entire or portion of a second octet can be reserved to indicate a non-preferred carrier ID.

In another embodiment, in addition to specifying the preferred carrier and non-preferred carrier, the UE may provide the base station with a ranked list of carriers in order of preference for uplink grants. Given the size of such a communication, this list may be provided via RRC signaling on a periodic basis. This ranking may be regularly updated with BSR transmissions indicating the preferred carriers and/or non-preferred carriers.

In another embodiment, a MAC-CE may be defined to communicate carrier preferences for uplink grants. As the UE radio condition changes, the MAC-CE can be used to update the UE's preference as well. Such a MAC-CE may be configured as part of a periodic transmission in place of, or in addition to, BSR or RRC carrier indications.

The proposed embodiment may further and indirectly provide indications for DTX on a specific carrier. That is, by indicating a non-preferred carrier, the UE may request to initiate DTX on the non-preferred carrier. In another embodiment, an additional UE signaling, or a MAC-CE can be added for a UE to request DTX on a specific carrier for a specific time. Thereby, the UE may provide DTX preferences to the base station based on, for example, thermal, maximum permissible exposure (MPE), interference control, and other UE specific control procedures.

The above embodiment and example provide a UE with additional capability to increase the uplink grant ratio on its preferred active carrier. This may allow the UE to improve performance relative to a device without the ability to adjust carrier ratios under the same network conditions. In this way, various UE specific impairments can be effectively overcome without the need for additional HW, while increasing processing capabilities.

FIG. 5is a diagram500illustrating a base station504in communication with a UE502according to some embodiments. The diagram500illustrates a process by which a UE502may identify and communicate a preferred and/or non-preferred uplink carrier to a base station. The UE502may be configured to operate using a plurality of carriers. For example, the UE502may be configured to use carrier aggregation or EN-DC.

At505, the UE502may provide base station504with a capability indication. The capability indication may indicate that the UE502supports an ability to identify and transmit an indication of the preferred and/or non-preferred uplink carrier to a base station. This indication may be, for example, an indication of a UE category that supports such measurement and indication. Alternatively, the indication may be indicated via RRC or MAC signaling. Alternatively, the UE may indicate such support during a random-access procedure. Furthermore, the capability may be indicated as part of an SR transmitted to the base station.

At510, the UE502may transmit an SR to base station504. The SR indicates to base station504that UE502has buffered data for transmission to the base station504.

At515, the base station504may transmit a signal to the UE502to transmit a BSR. The indication may include a BSR format that the UE502should send to the base station. The indicated BSR format may be an enhanced BSR format with fields for indicating a preferred carrier and/or a non-preferred carrier. The carrier indication in the BSR format may include two 4-bit fields for indicating the preferred carrier and non-preferred carrier, or may include one or more 8-bit fields for indicating the preferred and/or non-preferred carrier.

At520, the UE502may measure carrier quality. Step520may be performed on a continual basis at the UE, whereby the UE502continually monitors carrier quality. Alternatively, the UE502may measure carrier quality periodically or in response to certain base station communications, such as receipt of a grant to transmit BSR, or in response to internal conditions (e.g., having buffered data for uplink). Carrier quality may be measured based on one of more UE502conditions. As discussed above, these conditions may include, for example, self-jamming between downlink and uplink transmissions, thermal conditions impacting specific carrier and/or transmit chains, and non-WWAN interference. In one embodiment, the UE502may rank or prioritize the configured plurality of uplink carriers.

A525, the UE502may determine a preferred carrier from among a plurality of carriers as set forth above.

At530, the UE502may determine a non-preferred carrier from among a plurality of carriers which it is configured to use. Various measurable UE conditions may form the basis for selecting a non-preferred carrier.

Steps520,525, and530may be performed sequentially or may be performed as a combined step. Accordingly, the UE502may rank the carriers and thereby identify the preferred and non-preferred carriers based on the carrier rankings.

At535, UE502may transmit a BSR to the base station504. The BSR may be an enhanced BSR indicating the preferred carrier and/or the non-preferred carrier. As illustrated inFIG. 4, the carrier indication in the BSR may include two 4-bit fields for indicating the preferred carrier and non-preferred carrier or may include one or more 8-bit fields for indicating the preferred and/or non-preferred carrier.

Alternatively, the UE502may indicate the preferred carrier and/or non-preferred carrier via MAC or RRC signaling. The MAC signaling may include transmission of a MAC-CE including fields for the preferred carrier and/or non-preferred carrier, and may be transmitted periodically or aperiodically (e.g., based on a request from the base station). RRC signaling providing carrier preferences may include the preferred carrier and/or non-preferred carrier or may include a ranked list of a plurality of carriers. RRC signaling may also be transmitted periodically or aperiodically.

At540, the base station504may schedule an uplink grant. The uplink grant may be a cross-carrier grant or a self-scheduling grant (depending on the carrier configuration). The base station540may schedule the uplink grant for a specific carrier based in-part or in-whole on the preferred carrier and/or non-preferred carrier indication(s) from UE502. Additionally, the base station may schedule the UE based on measured CQI, network load, QoS requirements, the requirements of other UEs and other network conditions conventionally associated with carrier schedule criteria.

At545, the base station504may transmit an uplink grant to UE502. The grant may indicate the carrier and resource allocation for transmission of the buffered data. The indicated carrier may correspond to the preferred carrier, or not correspond to the non-preferred carrier.

At550, the UE550may transmit all or a portion of the buffered data to the base station504based on the carrier and resource allocation provided in the uplink grant.

Additionally (not shown), the base station504may modify the DTX configuration of a UE502based on the indication of the non-preferred carrier. For example, the base station504may deactivate transmission chains associated with the non-preferred carriers.

FIG. 6is a flowchart900of a method of wireless communication. The method may be performed by a UE (e.g., the UE104,502, the apparatus802/802′). The method covers a process by which a UE may indicate a preferred carrier for uplink transmission to a base station. The indication may be provided in a BSR, MAC-CE, or RRC communication. In response, the base station may adjust its criteria when selecting a carrier for subsequent uplink transmissions. In flowchart600, dashed lines represent optional steps.

At605, the UE may receive a BSR format from the base station. The BSR format may correspond to an enhanced BSR format, with a field to identify one or more carriers to the base station. The base station may indicate for the UE to use this enhanced BSR format by providing the UE with a corresponding LCID value. The new BSR format may include an octet that is defined to include two 4-bit carrier ID values. Alternatively, an entire or a portion of an octet can be reserved to indicate UE's most preferred carrier ID, and an entire or portion of a second octet can be reserved to indicate UE's non-preferred carrier ID.

At610, the UE may measure carrier quality. A UE configured to employ carrier aggregation or EN-DC may measure carrier quality over a plurality of uplink configured carriers. Carrier quality may be determined based on one of more UE measurable conditions. As discussed above, these conditions may include, for example, self-jamming between downlink and uplink transmissions, thermal conditions impacting specific carrier and/or transmit chains, and non-WWAN interference. In one embodiment, the UE502may rank or prioritize the configured uplink carriers.

At615, the UE may identify a first carrier corresponding to a first measured carrier quality. The first carrier may have a corresponding first measured carrier quality. In one example, the first carrier may be a preferred carrier from among a plurality of carriers. Various measurable UE conditions may form the basis for selecting a preferred carrier. In another example, the carrier may be a non-preferred carrier.

At620, the UE may identify a second carrier corresponding to a second carrier quality. The second carrier may be one of the plurality of carriers. The second carrier may be selected based on a second measured carrier quality. In one example, the first measured carrier quality may be a highest measured carrier quality associated with the plurality carriers, and the second measured carrier quality may be a lowest measured carrier quality associated with the plurality carriers.

In a first example, the measured carrier quality may correspond to self-interference within the UE. Self-interference may correspond to interference within the UE or to one or more downlink carriers caused by uplink carrier transmissions from the UE. That is, a transmit chain configured to transmit on one carrier may cause interference to a receive chain for another carrier. In this scenario, the measured carrier quality may be based on the magnitude of the self-interference to the downlink carrier that is the victim of the interference. The first carrier corresponds to an uplink carrier that causes the least amount of measurable self-interference.

In a second example, the measured carrier quality may correspond to a thermal metric associated with transmission on one or more uplink carriers. The thermal metric may be based on a transmit power and/or a thermal measurement associated with transmission on the one or more uplink carriers. For example, the thermal measurement may be a thermistor reading of a PA or phaser used for uplink transmission. In this example, the first carrier corresponds to an uplink carrier associated with a transmit chain having the lowest thermal metric. Similarly, the second carrier corresponds to an uplink carrier associated with a transmit chain having the highest thermal metric.

In a third example, the UE employs a non-WWAN network, and the carrier quality is based on interference experienced by a non-WWAN system (e.g., GNSS) due to uplink communications.

At625, the UE may send an uplink transmission with a carrier indication. The uplink transmission may be a BSR. BSR may have a format including a first carrier indicator field and a second carrier indicator field. Alternatively and as discussed above, the uplink transmission may include a MAC control element (CE) or RRC parameter having the first carrier indicator and the second carrier indicator.

Finally, at630, the UE may receive an uplink grant. The uplink grant indicates the carrier and resources on which the UE may transmit buffered data.

At635, the UE may additionally receive a DTX configuration. The DTX configuration may provide indications for DTX on a specific carrier. That is, the base station may indicate to the UE to initiate DTX on the non-preferred carrier. In another embodiment, additional UE signaling (e.g., a MAC-CE) can be introduced for a UE to request DTX on a carrier. Thereby, the UE may use the preferred and non-preferred carrier indication to provide DTX preferences to the base station based on, for example, thermal, MPE, interference control and other UE conditions. As such, the base station may provide a mechanism by which the UE may indicate over-heated transmit chains (e.g., including heavily active mmWave phasers) to the base station, and the base station may use DTX to allow those receive chains to cool down.

FIG. 7is a conceptual data flow diagram700illustrating the data flow between different means/components in an exemplary apparatus702. The apparatus may be a UE. The apparatus includes RF component704, carrier quality measurement component706, buffer monitoring component708, BSR generator710, DTX component712, and uplink transmission component714. RF component704receives downlink transmission716from base station750and transmits uplink transmissions734to base station750. Downlink transmissions716include various signaling from base station750, including reference signals, control information (e.g., uplink grants), and data. Uplink transmission724may include reference signals, control information (e.g., BSR, MAC-CE), and buffered data. Carrier quality measurement component706may receive and measure carrier quality from measurable signals718(e.g., reference signals, broadcast signals) received by RF component704. Buffer monitoring component708monitors the quantity of data for uplink transmission at apparatus702. BSR generator710generates a BSR726for transmission to base station750based on buffer data information724and carrier quality preferences/measurements722. DTX component712may receive a DTX configuration728from base station750. Uplink transmission component714processes uplink grants730from base station750, and provides uplink data732for transmission to base station750.

FIG. 8is a diagram800illustrating an example of a hardware implementation for an apparatus702′ employing a processing system814. The processing system814may be implemented with a bus architecture, represented generally by the bus824. The bus824may include any number of interconnecting buses and bridges depending on the specific application of the processing system814and the overall design constraints. The bus824links together various circuits including one or more processors and/or hardware components, represented by the processor804, the components704,706,708,710,712, and74and the computer-readable medium/memory806. The bus824may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system814may be coupled to a transceiver810. The transceiver810is coupled to one or more antennas820. The transceiver810provides a means for communicating with various other apparatus over a transmission medium. The transceiver810receives a signal from the one or more antennas820, extracts information from the received signal, and provides the extracted information to the processing system814, specifically the RF component704. In addition, the transceiver810receives information from the processing system814, specifically the RF component704, and based on the received information, generates a signal to be applied to the one or more antennas820. The processing system814includes a processor804coupled to a computer-readable medium/memory806. The processor804is responsible for general processing, including the execution of software stored on the computer-readable medium/memory806. The software, when executed by the processor804, causes the processing system814to perform the various functions described supra for any particular apparatus. The computer-readable medium/memory806may also be used for storing data that is manipulated by the processor804when executing software. The processing system814further includes at least one of the components704,706,708. The components may be software components running in the processor804, resident/stored in the computer readable medium/memory806, one or more hardware components coupled to the processor804, or some combination thereof. The processing system814may be a component of the UE250and may include the memory260and/or at least one of the TX processor268, the RX processor256, and the controller/processor259.

In one configuration, the apparatus702/702′ for wireless communication includes means for means measuring carrier quality on a plurality of carriers, means for identifying a first carrier from the plurality of carriers, the first carrier corresponding to a first measured carrier quality, means for sending an uplink transmission to a base station, the uplink transmission including an indication of the first carrier, means for receiving an uplink grant from the base station based on the uplink transmission. The aforementioned means may be one or more of the aforementioned components of the apparatus702and/or the processing system814of the apparatus702′ configured to perform the functions recited by the aforementioned means. As described supra, the processing system814may include the TX Processor268, the RX Processor256, and the controller/processor259. As such, in one configuration, the aforementioned means may be the TX Processor268, the RX Processor256, and the controller/processor259configured to perform the functions recited by the aforementioned means.

FIG. 9is a flowchart900of a method of wireless communication. The method may be performed by a base station (e.g., the base station102,504, or the apparatus1002/1002′). The method covers a process by which a base station receives a preferred carrier indication from a UE. The indication may be provided via a BSR, MAC-CE, or RRC communication. In response, the base station may adjust its criteria when selecting a carrier for subsequent uplink transmissions. In flowchart900, dashed lines represent optional steps.

At902, the base station may transmit an indication of a BSR format. The BSR format may correspond to an enhanced BSR format, with a field to identify one or more carriers to the base station. The base station may indicate for the UE to use this enhanced BSR format by providing the UE with a corresponding LCID value. The BSR format may be provided based on a determined UE capability. For example, the UE may indicate the ability to support the enhanced BSR by indicating a UE category or by providing MAC or RRC communications indicative of supporting an enhanced BSR.

At904, the base station may receive an uplink transmission, including a first carrier indicator. The first indicator may correspond to a first measured carrier quality. The first measured carrier quality may correspond to a highest measured carrier quality or lowest measured carrier quality. The uplink transmission may also include a second carrier indicator corresponding to a second measured carrier quality, in which case the first measured carrier quality may be a highest measured carrier quality, and the second measured carrier quality may be a lowest measured carrier quality. The uplink transmission may be a BSR (e.g., the enhanced BSR), a MAC control element (CE), or RRC signaling.

At906, the base station may schedule at least one uplink transmission. Scheduling the uplink transmissions may be based on the first carrier indicator. For example, the base station may adjust a rate of uplink grants scheduled on the first carrier based on the first measured carrier quality. For example, if the first carrier indicator corresponds to a preferred carrier, the base station may increase the ratio of uplink grants on the first carrier. Conversely, if the first carrier indicator corresponds to a non-preferred carrier, the base station may decrease the ratio of uplink grants on the first carrier or not schedule transmissions on the carrier. If the uplink transmission includes both a first carrier indicator associated with a preferred carrier and a second carrier indicator associated with a non-preferred carrier, the base station may increase the grant ratio of uplink grants on the first carrier and decrease the ratio of uplink grants on the second carrier.

Finally, at908, the base station may transmit an uplink grant to the UE.

At910, the base station may also transmit a DTX configuration to the UE. The DTX configuration may correspond to the first carrier and second carrier based on the information conveyed by the first carrier indicator and the second carrier indicator. The DTX configuration may provide for DTX on a specific carrier. That is, the base station may indicate to the UE to initiate DTX on the non-preferred carrier. As such, the base station may provide a mechanism by which an over-heated transmit chain (e.g., including active mmWave phasers) may use DTX to cool down.

FIG. 10is a conceptual data flow diagram1000illustrating the data flow between different means/components in an exemplary apparatus1002. The apparatus may be a base station. The apparatus includes RF component1004, scheduler component1006, DTX component1008, and BSR format selector1010. RF component1004transmits downlink transmissions1022to UE1050and receives uplink transmissions1012from UE1050. Downlink transmissions1022include various signaling, including reference signals, control information (e.g., uplink Grants), and data. Uplink transmission1012reference signals, control information (e.g., BSR, MAC-CE), and buffered data. Scheduler1006receives scheduling control information1014(e.g., CQI measurement, BSR) generates downlink assignments and uplink grants1016for UE1050. DTX components generate DTX configurations1018for UE1050based on UE parameters, including preferred and non-preferred carrier indication information. BSR Format Selector1010transmits an indicator1020to UE1050indicating the type of BSR to transmit to apparatus1002.

FIG. 11is a diagram1100illustrating an example of a hardware implementation for an apparatus1002′ employing a processing system1114. The processing system1114may be implemented with a bus architecture, represented generally by the bus1124. The bus1124may include any number of interconnecting buses and bridges depending on the specific application of the processing system1114and the overall design constraints. The bus1124links together various circuits including one or more processors and/or hardware components, represented by the processor1104, the components1004,1006,1008,1010, and the computer-readable medium/memory1106. The bus1124may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system1114may be coupled to a transceiver1110. The transceiver1110is coupled to one or more antennas1120. The transceiver1110provides a means for communicating with various other apparatus over a transmission medium. The transceiver1110receives a signal from the one or more antennas1120, extracts information from the received signal, and provides the extracted information to the processing system1114. In addition, the transceiver1110receives information from the processing system1114, and based on the received information, generates a signal to be applied to the one or more antennas1120. The processing system1114includes a processor1104coupled to a computer-readable medium/memory1106. The processor1104is responsible for general processing, including the execution of software stored on the computer-readable medium/memory1106. The software, when executed by the processor1104, causes the processing system1114to perform the various functions described supra for any particular apparatus. The computer-readable medium/memory1106may also be used for storing data that is manipulated by the processor1104when executing software. The processing system1114further includes at least one of the components1004,1006,1008, and1010. The components may be software components running in the processor1104, resident/stored in the computer readable medium/memory1106, one or more hardware components coupled to the processor1104, or some combination thereof. (The processing system1114may be a component of the base station210and may include the memory276and/or at least one of the TX processor216, the RX processor270, and the controller/processor275

In one configuration, the apparatus_1002/_1002′ for wireless communication includes means for means for receiving an uplink transmission from a, the uplink transmission including a first carrier indicator, the first carrier indicator corresponding to a first measured carrier quality for a first carrier, means for scheduling uplink transmissions based on first carrier indicator, and means for transmitting an uplink grant from the base station based on the uplink transmission. The aforementioned means may be one or more of the aforementioned components of the apparatus_1002and/or the processing system1114of the apparatus_1002′ configured to perform the functions recited by the aforementioned means. As described supra, the processing system1114may include the TX Processor216, the RX Processor270, and the controller/processor275. As such, in one configuration, the aforementioned means may be the TX Processor216, the RX Processor270, and the controller/processor275configured to perform the functions recited by the aforementioned means.