ON-DEMAND SYSTEM INFORMATION FOR FLEXIBLE CELLS

Methods, systems, and devices for wireless communications are described. In a wireless communications system, a base station may support a flexible cell with a set of carriers including an anchor carrier and two or more non-anchor carriers. In some examples, a user equipment (UE) may select, from among the set of carriers and based on receiving an indication of the configuration, a carrier for transmission of a request for system information associated with the flexible cell. The UE may transmit the request for system information to the base station via the selected carrier. Additionally or alternatively, the UE may select a carrier for reception by the UE of an acknowledgement for the request for the system information, and the UE may receive the acknowledgement for the request for system information via the selected carrier.

FIELD OF TECHNOLOGY

The following relates to wireless communications, including on-demand system information for flexible cells.

BACKGROUND

In some wireless communications systems, a base station may support a flexible cell including multiple carriers, and may communicate with a UE via one or more carriers. Techniques for selecting carriers for particular communications may be improved.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support on-demand system information for flexible cells. Generally, the described techniques provide for a user equipment (UE) to select one or more carriers of a flexible cell for uplink transmission and downlink reception in an on-demand system information procedure. In some cases, a base station may support a flexible cell configured with a set of carriers including an anchor carrier and two or more non-anchor carriers. A UE may select a carrier from the set of carriers for transmission of a request for system information with the flexible cell, and the UE may transmit the request for the system information via the selected carrier. In some examples, the carrier may be selected for the transmission of the request based on a carrier identifier, a reference signal measurement, or any combination thereof. Additionally or alternatively, the UE may select a carrier from the set of carriers for reception of an acknowledgement for the request for system information, where the carrier may be the same or different from the carrier selected for the transmission of the request. In some examples, the UE may receive the acknowledgement for the request for system information from the base station via the selected carrier. In some examples, the carrier for reception of the acknowledgement may be selected for the reception of the acknowledgement based on control message, a shared channel message, a random access preamble, or any combination thereof.

A method for wireless communication at a UE is described. The method may include receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers, selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell, and transmitting the request for the system information via the selected carrier.

An apparatus for wireless communication at a UE is described. The apparatus may include memory, a transceiver, and at least one processor of a UE, the at least one processor coupled with the memory and the transceiver. The at least one processor may be configured to cause the apparatus to receive, via the transceiver, an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers, select, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell, and transmit, via the transceiver, the request for the system information via the selected carrier.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers, means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell, and means for transmitting the request for the system information via the selected carrier.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to receive an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers, select, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell, and transmit the request for the system information via the selected carrier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the configuration for the flexible cell may include operations, features, means, or instructions for receiving an indication of a set of carrier identifiers including a respective carrier identifier for each carrier of the set of carriers and receiving an indication of the respective carrier identifier for the selected carrier, where the indication of the respective carrier identifier for the selected carrier indicates which carrier the UE may be to select for transmission of the request for the system information.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the configuration for the flexible cell may include operations, features, means, or instructions for receiving radio resource control (RRC) signaling that indicates the set of carrier identifiers, the respective carrier identifier for the selected carrier, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the set of carrier identifiers may include operations, features, means, or instructions for receiving system information that indicates the set of carrier identifiers, the respective carrier identifier for the selected carrier, or both.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a reference signal from the base station and measuring a received power level for the reference signal, where selecting the carrier based on the configuration for the flexible cell includes selecting the carrier for transmission of the request for the system information based on the received power level for the reference signal.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for comparing the received power level for the reference signal to one or more thresholds, where receiving the indication of the configuration for the flexible cell comprises receiving an indication of the one or more thresholds, and where selecting the carrier for transmission of the request for the system information may be based on the comparing.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the one or more thresholds includes a single threshold and the method, apparatuses, and non-transitory computer-readable medium may include further operations, features, means, or instructions for using the single threshold to select one of the two or more non-anchor carriers to use as a supplemental uplink (SUL) carrier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the set of carriers includes a set of multiple subsets of one or more carriers, the set of multiple subsets corresponding to a set of multiple received power ranges that may be each delimited by at least one threshold of the one or more thresholds, comparing the received power level for the reference signal to the one or more thresholds includes determining that the received power level for the reference signal may be within a first received power range of the set of multiple received power ranges, and selecting the carrier for transmission of the request for the system information includes selecting the carrier from a first subset of carriers based on the first subset of carriers corresponding to the first received power range.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, selecting the carrier from the first subset of carriers may include operations, features, means, or instructions for selecting a first carrier based on the first carrier being associated with a lowest carrier identifier from among one or more carrier identifiers corresponding to the first subset of carriers.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first carrier may be lower in frequency than each other carrier in the first subset of carriers.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the request for the system information may include operations, features, means, or instructions for transmitting a random access preamble via the selected carrier, where the random access preamble may be one of a set of random access preambles each corresponding to a respective set of system information associated with the flexible cell, and where the request for system information associated with the flexible cell includes a request for the respective set of system information corresponding to the transmitted random access preamble.

A method for wireless communication at a UE is described. The method may include receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers, selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell, transmitting, to the base station, the request for the system information associated with the flexible cell, and receiving the acknowledgement for the request for the system information via the selected carrier.

An apparatus for wireless communication at a UE is described. The apparatus may include memory, a transceiver, and at least one processor of a UE, the at least one processor coupled with the memory and the transceiver. The at least one processor may be configured to cause the apparatus to receive, via the transceiver, an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers, select, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell, transmit, via the transceiver and to the base station, the request for the system information associated with the flexible cell, and receive, via the transceiver, the acknowledgement for the request for the system information via the selected carrier.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers, means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell, means for transmitting, to the base station, the request for the system information associated with the flexible cell, and means for receiving the acknowledgement for the request for the system information via the selected carrier.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to receive an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers, select, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell, transmit, to the base station, the request for the system information associated with the flexible cell, and receive the acknowledgement for the request for the system information via the selected carrier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the configuration for the flexible cell may include operations, features, means, or instructions for receiving, prior to selecting the carrier, additional system information that indicates the configuration for the flexible cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the additional system information includes an indication of a carrier identifier for the selected carrier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, an absence from the additional system information of an indication of a carrier identifier for the selected carrier includes an indication that the UE may be to select the anchor carrier as the selected carrier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the acknowledgement for the request for the system information via the selected carrier may include operations, features, means, or instructions for receiving a control message via the selected carrier and receiving a shared channel message via the selected carrier, the shared channel message scheduled by the control message and including the acknowledgement.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the configuration for the flexible cell may include operations, features, means, or instructions for receiving a first indication of a first carrier of the set of carriers, where the first carrier may be for receiving a control message, and the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a second indication of a second carrier of the set of carriers, where the second carrier is the selected carrier and may be for receiving a shared channel message that may be scheduled by the control message and includes the acknowledgement.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the configuration for the flexible cell may include operations, features, means, or instructions for receiving, prior to selecting the carrier, additional system information that includes the first indication of the first carrier and the second indication of the second carrier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the configuration for the flexible cell may include operations, features, means, or instructions for receiving, prior to selecting the carrier, additional system information that includes the first indication of the first carrier and receiving the second indication of the second carrier within the control message.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first carrier may be different than the second carrier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first carrier and the second carrier are a same carrier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of the configuration for the flexible cell may include operations, features, means, or instructions for receiving an indication of a set of random access preambles for the UE to use for transmitting system information requests.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the request for the system information associated with the flexible cell may be transmitted using a preamble of the set of random access preambles, and the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving the system information associated with the flexible cell via a second carrier of the set of carriers, where the acknowledgement for the request includes medium access control (MAC) signaling that indicates the second carrier.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the selected carrier.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, prior to transmitting the request for the system information associated with the flexible cell, a first system information block (SIB) via a second carrier of the set of carriers and receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the second carrier.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, prior to transmitting the request for the system information associated with the flexible cell, a synchronization signal block (SSB) via a second carrier of the set of carriers and receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the second carrier.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the request for the system information includes transmitting a random access preamble and receiving the acknowledgement for the request for the system information includes receiving a random access response (RAR) message in response to transmitting the random access preamble.

DETAILED DESCRIPTION

A base station may include or support a flexible cell (e.g., an elastic cell), which may be a cell with a collection of multiple carriers. A set of carriers of the flexible cell may include an anchor carrier and one or more non-anchor carriers. For example, the flexible cell may include an anchor carrier, a first non-anchor carrier, and a second non-anchor carrier. Other examples of a flexible cell may include any quantity of carriers (e.g., one anchor carrier and one or more non-anchor carriers, such as one non-anchor carrier or three or more non-anchor carriers).

In some cases, system information (e.g., on-demand system information) may be communicated between the base station and a user equipment (UE) via any carrier (e.g., the anchor carrier or a non-anchor carrier) of the flexible cell. For example, the base station may transmit system information (e.g., on-demand system information) to the UE based on receiving a request for system information from the UE. Because multiple carriers (e.g., an anchor carrier and up to N non-anchor carriers) may be available for communications on the flexible cell, including for system information, the UE may need to determine (e.g., select) which carrier to use for transmission of a request for system information, for example whether to use a non-anchor carrier (and if so, which one) or the anchor carrier. Additionally or alternatively, the UE may need to determine (e.g., select) which carrier to use (e.g., monitor) for reception of signaling from the base station that is responsive to a request for system information, such as an acknowledgement of the request for system information or the requested system information.

Techniques described herein provide for a UE to select one or more carriers of a flexible cell for uplink transmission and downlink reception in an on-demand system information procedure. In some cases, a base station may support a flexible cell configured with a set of carriers including an anchor carrier and two or more non-anchor carriers. A UE may select a carrier from the set of carriers for transmission of a request for system information with the flexible cell, and the UE may transmit the request for the system information via the selected carrier. In some examples, the carrier may be selected for the transmission of the request based on a carrier identifier, a reference signal measurement, or any combination thereof. Additionally or alternatively, the UE may select a carrier from the set of carriers for reception of an acknowledgement for the request for system information, where the carrier may be the same or different from the carrier selected for the transmission of the request.

The UE may receive the acknowledgement for the request for system information from the base station via the selected carrier. In some examples, the carrier for reception of the acknowledgement may be selected for the reception of the acknowledgement based on control message, a shared channel message, a random access preamble, or any combination thereof. Additionally or alternatively, the UE may select a carrier from the set of carriers for reception of the system information that is requested by a request for system information, where the carrier may be the same or different from the carrier selected for the transmission of the request and may be the same or different from the carrier selected for the reception of the acknowledgement of the request. In some examples, the UE may transmit the request for the system information using a random access preamble. The UE may receive the acknowledgement for the request which may include medium access control (MAC) signaling indicating a carrier for reception of the requested system information by the UE. Additionally or alternatively, if the base station fails to explicitly indicate a carrier selected for reception of the requested system information by the UE, the UE may receive the requested system information via the same carrier on which the UE received the acknowledgement, a system information block (SIB), or a synchronization signal block (SSB).

A base station105may include or support a flexible cell (e.g., an elastic cell), which may be a cell with a collection of multiple carriers (e.g., any combination of carriers). A set of carriers of the flexible cell may include an anchor carrier and one or more non-anchor carriers. For example, the flexible cell may include an anchor carrier, a first non-anchor carrier, and a second non-anchor carrier. Other examples of a flexible cell may include any quantity of carriers (e.g., one anchor carrier and one or more non-anchor carriers, such as one non-anchor carrier or three or more non-anchor carriers). In some examples, the carriers in the flexible cell may include any combination of carriers for FDD operations, TDD operations, and supplemental uplink (SUL) operations, which may enable flexible use of different carriers in NR communications. For example, the flexible cell may include a non-anchor carrier 1 (e.g., 1.8 gigahertz (GHz) FDD), an anchor carrier (e.g., 2.6 GHz TDD) and a non-anchor carrier 2 (e.g., 2.3 GHz SUL), where the anchor carrier may operate at a higher frequency than the non-anchor carriers. In some examples, the carriers in the flexible cell may be non-contiguous.

The base station105may perform communications over a set of carriers using carrier aggregation techniques in which the base station105may configure multiple cells separately for each carrier of the set of carriers, and the base station105may configure a UE115with carrier aggregation capabilities. However, carrier aggregation may use a high signaling overhead and complex cell management. As such, to reduce the amount of signaling overhead and to reduce the complexity of cell management, the base station105may use the flexible cell to transmit system information to a UE115. For example, using the flexible cell, the base station105may transmit an SSB (e.g., minimum system information) on the anchor carrier of the flexible cell, and the base station105may transmit other system information (e.g., on-demand system information) and perform related procedures in either the anchor carrier or one of the multiple non-anchor carriers. As such, the flexible cell may introduce more flexibility into the wireless communications system100by enabling the base station105to perform communications (e.g., random access procedures) using carriers configured for a particular cell for those particular communications.

In some examples, a base station105may transmit minimum system information (e.g., a master information block (MIB), a SIB) to a UE115. For example, the base station105may periodically broadcast an MIB to the UE115over a broadcast channel, or the base station105may unicast or periodically broadcast a SIB1 to one or multiple UEs115over a downlink shared channel. Additionally or alternatively, the base station105may transmit other system information (e.g., system information other than an MIB or a SIB) to the UE115.

In some cases, UEs115in an idle state (e.g., RRC_IDLE) or an inactive state (e.g., RRC_INACTIVE) may trigger a random access procedure by transmitting a request for other system information to the base station105(e.g., a Msg1, a physical random access channel (PRACH) preamble). In some examples, after receiving minimum system information including scheduling information (e.g., a SIB1), a UE115may determine a broadcast status of a system information message (e.g., via an si-BroadcastStatus information element). The broadcast status may be included in SIB1. In some examples, the broadcast status may indicate if the base station105is broadcasting one or several SIBs within the system information message. For example, if the broadcast status (e.g., in si-BroadcastStatus) is set to “broadcasting,” the UE115may acquire the corresponding one or more SIBs (e.g., without using a random access procedure) via one or more broadcast transmissions. If the broadcast status is set to “notbroadcasting,” however, the UE115may request system information (e.g., one or more SIBs) in order to receive such system information in an on-demand basis, and so-obtained system information may be referred to as on-demand system information. For example, the UE115may initiate a random access procedure to acquire the corresponding one or more SIBs. In some examples, if the base station105configures the UE115with PRACH resources for a request for system information, then the UE115may use a contention-free random access (CFRA) procedure. Otherwise, the UE115may use a contention-based random access (CBRA) procedure.

In some examples, a UE115may select a normal uplink (NUL) carrier, an SUL carrier, or both for uplink transmissions in an on-demand system information (e.g., CFRA) procedure. In some cases, an SUL carrier may be configured in addition to an NUL carrier for enhanced uplink coverage, reliability, and throughput. A base station105may provide SUL carrier information in a SIB1. Additionally or alternatively, for a UE115performing a random access procedure for on-demand system information, the base station105may configure the SUL carrier for transmission of a PRACH (e.g., Msg1). In some cases, the base station105may select whether the NUL carrier or the SUL carrier may be used for the PRACH transmission. The base station105may explicitly indicate in the SIB1 whether the UE115is to use the NUL carrier or the SUL carrier.

If the base station105fails to provide an explicit indication, then the UE115may use the SUL carrier if a reference signal received power (RSRP) of a downlink reference signal is less than a threshold for downlink pathloss (e.g., rsrp-ThresholdSSB-SUL information element configured in the SIB1). If the RSRP is greater than the threshold, then the UE115may use the NUL carrier. For example, the SUL (e.g., a non-anchor carrier) may have a lower frequency than the NUL carrier, and therefore the SUL carrier may be more reliable than the NUL carrier. As such, if the RSRP is lower than the threshold for the SUL carrier, then the NUL carrier may have a lower RSRP due to its higher frequency compared to that of the SUL carrier. That is, when the RSRP for the SUL carrier is low, generally indicating poor channel conditions for the SUL carrier and the NUL carrier, then the UE115may use the SUL carrier because it may be more robust than the NUL carrier (e.g., due to the lower frequency of the SUL carrier).

A base station105may support a flexible cell configured with a set of carriers including N non-anchor carriers (e.g., where Nis larger than 1) and an anchor carrier. The set of carriers may be configured for FDD operations, TDD operations, SUL operations, or any combination thereof. In some cases, the base station105may configure a UE115to perform an on-demand system information procedure over one or multiple carriers of the set of carriers. Because the set of carriers may be available for communications on the flexible cell, the UE115may be unaware of which carrier to use (e.g., to monitor) for transmission of a request for the system information and reception of an acknowledgement for the request.

The techniques described herein may enable a UE115to select one or more carriers from the set of carriers on the flexible cell for uplink transmission and downlink reception in an on-demand system information procedure. In some examples, the UE115may select a carrier for transmission of an uplink random access message (e.g., an uplink PRACH in Msg1) to request on-demand system information and one or more carriers for reception of one or more responsive downlink messages. For example, the UE115may select a carrier for the receiving a control message with downlink control information (DCI) (e.g., a physical downlink control channel (PDCCH)). The downlink control message may schedule a shared channel message (e.g., a physical downlink shared channel (PDSCH) carrying Msg2) with the acknowledgement for the request for system information in the shared channel message. Additionally or alternatively, the downlink control message may schedule a shared channel message (e.g., PDSCH) carrying the requested system information. Techniques are further described herein by which the UE115may select one or more carriers for receiving such shared channel messages.

In some examples, the UE115may select a carrier for transmitting the request based on a carrier identifier, a reference signal measurement, or any combination thereof. Additionally or alternatively, the UE115may select a carrier from the set of carriers for reception of the acknowledgement for the request for system information from the base station105, where the carrier may be the same or different than the carrier selected for the transmission of the request. In some examples, the UE115may receive the acknowledgement for the request from the base station105via the selected carrier. Additionally or alternatively, the UE115may receive the requested system information via a selected carrier after receiving the acknowledgement for the request. For example, the UE115may receive the acknowledgement for the request, which may include MAC signaling indicating a carrier for reception of the requested system information. If the base station105fails to explicitly indicate a carrier for the reception of the requested system information, the UE115may receive the requested system information via the same carrier on which the UE115received the acknowledgement, a SIB, or an SSB.

FIG.2illustrates an example of a wireless communications system200that supports on-demand system information for flexible cells in accordance with aspects of the present disclosure. In some examples, the wireless communications system200may implement aspects of the wireless communications system100or may be implemented by aspects of the wireless communications system100. For example, the wireless communications system200may include UEs115and a base station105-a, which may be examples of corresponding devices described herein. The wireless communications system200may include features for improved communications between the UEs115and the base station105-a.

The base station105-amay support a flexible cell205, which may include a set of carriers. The set of carriers may include an anchor carrier215and two of more non-anchor carriers210, the set of carriers supporting FDD operations, TDD operations, SUL operations, or any combination thereof. For example, the flexible cell205may include a non-anchor carrier210-a(e.g., an FDD carrier), the anchor carrier215(e.g., a TDD carrier), and a non-anchor carrier210-b(e.g., an SUL carrier). In some examples, the flexible cell205may include any number of non-anchor carriers210and anchor carriers215supporting different operations.

The base station105-aand the UE115-amay communicate via communications links220. For example, the UE115-amay receive downlink communications from the base station105-avia a communications link220-aand the UE115-amay transmit uplink communications to the base station105-avia a communications link220-b. In some cases, the UE115-amay receive an indication of a configuration225for the flexible cell205. Based on the indication of the configuration225, the UE115-amay select, from among the set of carriers of the flexible cell205(e.g., the non-anchor carriers210and the anchor carrier215), a carrier for transmission of a request230for system information associated with the flexible cell205, a carrier for reception of an acknowledgement235for the request230, a carrier for reception of the requested system information240, or any combination thereof.

For example, the UE115-amay select a carrier to transmit the request as part of an on-demand system information procedure. That is, the UE115-amay select a carrier for transmission of an uplink random access message, such as a PRACH (e.g., Msg1), to request on-demand system information.

In some examples, the base station105-amay (e.g., as part of the configuration225) explicitly indicate the carrier that the UE115-amay select for the transmission of the request230(e.g., the PRACH transmission, the Msg1). Each carrier in the flexible cell205may be associated with a carrier identifier, which the base station105-amay indicate via the indication of the configuration225, which may be transmitted as part of system information, via RRC signaling, or both. Thus, in some examples, the UE115-amay receive an indication of a set of carrier identifiers including a respective carrier identifier for each carrier in the set of carriers. Additionally or alternatively, the base station105-amay explicitly indicate (e.g., as part of the configuration225, which may be included in system information or RRC signaling) a carrier identifier corresponding to the carrier the UE115-ais to use to transmit the request230. For example, the UE115-amay receive an indication of the respective carrier identifier corresponding to the carrier that the UE115-ais to select for the transmission of the request230.

In some cases, the base station105-amay refrain from explicitly indicating a carrier selection to the UE115-a. For example, the UE115-amay select a carrier to transmit the request230(e.g., the PRACH message, the Msg1) based on a measurement (e.g., an RSRP measurement) of a reference signal. The reference signal may be a downlink pathloss reference signal (e.g., an SSB) transmitted on the anchor carrier215of the flexible cell205. For example, the UE115-amay receive a reference signal from the base station105-a. The UE115-amay measure an RSRP for the reference signal, and may select a carrier of the flexible cell205for transmission of the request230based on the measured RSRP. In some examples, the UE115-amay select a carrier for uplink transmissions in a random access procedure by comparing a measured RSRP of the reference signal with one or multiple RSRP thresholds. Whether to select the carrier to transmit the request230based on a measurement of a reference signal, one or more thresholds for use in selecting the carrier to transmit the request230based on a measurement of a reference signal, a mapping between the one or more thresholds and different carriers (or groups of carriers) of the flexible cell, or any combination thereof may be indicated as part of the configuration225.

In some cases, the base station105-amay configure one RSRP threshold for both SUL carrier selection and for selection of carrier for transmitting the request230. For example, the UE115-amay reuse an RSRP threshold configured for SUL carrier selection (e.g., rsrp-ThresholdSSB-SUL). That is, the UE115-amay use a single threshold to select one of the two or more non-anchor carriers210to use as an SUL carrier. Alternatively, the base station105-amay configure the UE115-awith an RSRP threshold to use for the selection of the carrier to transmit the request230that is different from the RSRP threshold configured for SUL carrier selection. In some examples, the base station105-amay configure multiple RSRP thresholds and indicate a mapping between the multiple RSRP thresholds and the set of carriers in the flexible cell205, for example, via RRC signaling. In some cases, the set of carriers may include one or more subsets of one or more carriers, where each subset corresponds to an RSRP threshold range each delimited by at least one RSRP threshold of the multiple RSRP thresholds. That is, each subset of carriers in the flexible cell205may correspond to a range of RSRP thresholds. In some examples, the mapping between the RSRP thresholds and the set of carriers may indicate, to the UE115-a, which carriers may be in each subset of carriers.

As an example, the base station105-amay configure two RSRP threshold values, T1 and T2, where T1 may be less than T2. The UE115-amay compare the measured RSRP for the reference signal to one or both RSRP thresholds by determining that the RSRP for the reference signal is within an RSRP threshold range of the multiple RSRP threshold ranges. The UE115-amay select the carrier for transmission of the request230based on selecting the carrier from a first subset of carriers corresponding to the RSRP threshold range. For example, of the RSRP of the reference signal is less than T1 (e.g., within a first RSRP threshold range including the lowest RSRP threshold value up to the RSRP threshold value T1), then the UE115-amay select a carrier from a first subset (e.g., subset 1) of carriers (e.g., {f1, f2, . . . , fk}). If the RSRP of the reference signal is greater than or equal to T1 and less than T2 (e.g., within a second RSRP threshold range including RSRP threshold values T1 to T2), the UE115-amay select a carrier from a second subset (e.g., subset 2) of carriers (e.g., {f{k+1}, f{k+2}, . . . , f{2k}}, where fk<f(k+1)). If the RSRP of the reference signal is greater than or equal to T2 (e.g., within a third RSRP threshold range including the RSRP threshold value T2 to the highest RSRP threshold value), then the UE115-amay select a carrier from a third subset (e.g., subset 3) of carriers (e.g., {f{2k+1}, f{2k+2}, . . . , f{N+1}}. In some examples, one of the multiple RSRP thresholds may be the RSRP threshold configured for SUL carrier selection.

If the size of the subset of carriers is one (e.g., if there is one carrier in a subset of carriers corresponding to an RSRP threshold range), then the UE115-amay select the one carrier in the subset for the transmission of the request230if the measured RSRP is within the corresponding RSRP threshold range. If the size of the subset of carriers corresponding to the RSRP threshold range is greater than 1 (e.g., if there are multiple carriers in the subset of carriers corresponding to the RSRP threshold range), then the UE115-amay select the carrier in the subset of carriers with the smallest carrier identifier. In some examples, the smallest carrier identifier may correspond to the carrier with the lowest carrier frequency in the subset. That is, the selected carrier may be lower in frequency than each other carrier in the same subset of carriers.

Once the UE115-ahas selected a carrier from the flexible cell205, the UE115-amay transmit the request230via the selected carrier. In some cases (e.g., in addition to selecting the carrier for the transmission of the request230), the UE115-amay select a carrier from the flexible cell205for reception of an acknowledgement235for the request230associated with the flexible cell. The base station105-amay transmit the acknowledgement235via a Msg2 (e.g., PDCCH, PDSCH, or both).

In some examples, prior to selecting the carrier for reception of the acknowledgement235, the UE115-amay receive additional system information (e.g., minimum system information, such as a MIB or SIB1) that may indicate the configuration225for the flexible cell. The additional system information may include an indication of a carrier identifier corresponding to the selected carrier. For example, the base station105-amay explicitly indicate the carrier the UE115-ais to select to receive the acknowledgement235(e.g., the Msg2 PDCCH, PDSCH) via the additional information. In some cases, if the base station105-arefrains from explicitly indicating the carrier selection, the UE115-amay select the anchor carrier215to receive the acknowledgement235(e.g., the anchor carrier215may be a default carrier for receiving the acknowledgement235). That is, an absence from the additional system information of an indication of a carrier identifier for the selected carrier may indicate that the UE115-ais to select the anchor carrier215as the selected carrier, which may be the carrier over which the UE115-areceives the additional system information minimum system information (e.g., a MIB or SIB1), an SSB, or both. In some cases, the UE115-amay receive the same indication for a carrier selection for both a control message (e.g., a PDCCH) and a shared channel message (e.g., a PDSCH). That is, the UE115-amay receive the control message and the shared channel message in the same carrier as indicated by the base station105-a(e.g., as indicted via a single indication).

In some cases, decoupling the carrier indication for the control channel and the shared channel (e.g., indicating a carrier selection separately for the control channel and the shared channel) may increase flexibility and enhance the capacity of the control channel. For example, for the reception of the acknowledgement235(e.g., Msg2), the UE115-amay use to a first carrier to receive an associated control message (e.g., PDCCH) including DCI scheduling and a second carrier to receive a shared channel message (e.g., PDSCH carrying Msg2), where the shared channel message may be scheduled by the DCI and may include the acknowledgement235. For example, the UE115-amay receive the control message via a selected carrier, where the DCI in the control message may schedule the shared channel message and indicate a carrier for reception of the shared channel message. The UE115-amay receive the shared channel message via the carrier indicated by the corresponding DCI, where the shared channel message may include the acknowledgement235, and where the carrier indicated by the corresponding DCI may be the same or different than the selected carrier via with the control message (and hence the DCI) is received.

In some examples, the UE115-amay receive two separate carrier indications in system information (e.g., as part of the configuration225) from the base station105-a(e.g., corresponding to the control message and the shared channel message). For example, the UE115-amay receive a first indication of a first carrier of the set of carriers for the flexible cell205, the first carrier for receiving a control message. The UE115-amay receive a second indication of a second carrier of the set of carriers, where the second carrier is the selected carrier and may be for receiving a shared channel message that is scheduled by the control message and that includes the acknowledgement235. In some examples, the UE115-amay receive an indication for the control message in system information (e.g., as part of the configuration225) from the base station105-a, and the UE115-amay receive another indication for the shared channel message in the control message, where the shared channel message may carry the acknowledgement235(e.g., the Msg 2). For example, prior to selecting the carrier, the UE115-amay receive additional system information (e.g., minimum system information, such as a MIB or a SIB1) including the first indication of the first carrier and the second indication of the second carrier. Additionally or alternatively, prior to selecting the carrier, the UE115-amay receive additional system information (e.g., minimum system information) that includes the first indication of the first carrier and the UE115-amay receive the second indication of the second carrier within the control message. Such additional system information may be the indication of the configuration225. The first and second carriers may be the same carrier (e.g., both the anchor carrier215) or different carriers (e.g., the non-anchor carrier210-aand the anchor carrier215).

In some cases, the UE115-amay use PRACH preambles to request on-demand system information (e.g., an on-demand SIB). For example, the UE115-amay receive (e.g., as part of the configuration225) an indication of a set of random access (e.g., PRACH) preambles for the UE115-ato use for transmitting the request230. Each random access preamble of the set may correspond to a respective set of system information associated with the flexible cell (e.g., as indicated as part of the configuration225), and hence which random access preamble is transmitted as part of the request230may indicate which set of on-demand system information240is requested. The UE115-amay transmit a random access preamble via the selected carrier, where the random access preamble may be one of the set of random access preambles each corresponding to a respective set of system information associated with the flexible cell, and where the request230may include a request for the respective set of system information corresponding to the transmitted random access preamble.

In response to the request230that includes or is otherwise based on the random access preamble, the base station105-amay transmit a random access response (RAR), which may be or include the acknowledgement235as described herein. The RAR message may be a MAC RAR and may be included in a MAC subPDU, where the carrier that the UE115-ais to use (e.g., select) to receive the requested system information240may be indicated by the MAC RAR. The MAC subPDU may be included in a MAC control element (MAC-CE), for example, or in any other type of MAC message. Thus, for example, the UE115-amay transmit the request230based on (e.g., as including) the random access preamble, and the acknowledgement235may include MAC signaling that indicates a carrier via which the UE115-ais to receive the requested system information240. The carrier via which the request is transmitted and the carrier via which the acknowledgement is received may be separately selected as described elsewhere herein.

In some cases, the base station105-amay refrain from explicitly indicating a selected carrier for the UE115-ato receive the system information240(e.g., the requested system information). For example, to receive the system information240, the UE115-amay select the same carrier in which the UE115-areceived the control message, the shared channel message, or both carrying the acknowledgement235for receiving the system information240. As another example, in some cases, to receive the system information240, the UE115-amay select the same carrier in which the UE115-amay receive a SIB1 for receiving the system information240. For example, prior to transmitting the request230, the UE115-amay receive a first SIB (e.g., SIB1) via a second carrier of the set of carriers, and after receiving the acknowledgement235, the UE115-amay receive the system information240via the second carrier. And as yet another example, in some cases, to receive the system information240, the UE115-amay select the same carrier in which the UE115-amay receive an SSB for receiving the system information240. For example, prior to transmitting the request230, the UE115-amay receive an SSB via the second carrier, and after receiving the acknowledgement235, the UE115-amay receive the system information240via the second carrier. In some cases, information indicated in the configuration225may indicate to the UE115-awhich other signaling correspond to the carrier the UE115-ais to use to receive the system information240(e.g., whether the UE115-ais to receive the system information240in the same carrier as one or more messages associated with the acknowledgement235, in the same carrier as a first SIB, or in the same carrier as an SSB).

FIG.3illustrates an example of a process flow300that supports on-demand system information for flexible cells in accordance with aspects of the present disclosure. The process flow300may implement aspects of wireless communications systems100and200, or may be implemented by aspects of the wireless communications system100and200. For example, the process flow300may illustrate operations between a UE115-band a base station105-b, which may be examples of corresponding devices described herein. In the following description of the process flow300, the operations between the UE115-band the base station105-bmay be transmitted in a different order than the example order shown, or the operations performed by the UE115-band the base station105-bmay be performed in different orders or at different times. Some operations may also be omitted from the process flow300, and other operations may be added to the process flow300.

As described with reference toFIG.2, the UE115-bmay select one or more carriers of a flexible cell for uplink transmissions and downlink reception in an on-demand system information procedure. In some cases, the on-demand system information procedure may include the UE115-brequesting system information from the base station105-busing a CFRA procedure. In some examples, the system information may be minimum system information (e.g., an MIB, a SIB) or other system information (e.g., a SIB2).

At305, the UE115-bmay receive minimum system information (e.g., an MIB) from the base station105-b. In some examples, the base station105-bmay periodically broadcast an MIB over a broadcast channel.

At310, the UE115-bmay receive minimum system information (e.g., a SIB1) from the base station105-b. In some cases, the base station105-bmay periodically broadcast a SIB1 on a downlink shared channel, or the base station105-bmay periodically transmit (e.g., unicast) the SIB1 to a particular UE115. In some examples, the base station105-bmay configure the UE115-bwith dedicated random access resources for a request for system information in the SIB1 (e.g., in SI-RequestConfig within an SI-SchedulingInfo information element in the SIB1).

At315, the UE115-bmay receive a reference signal from the base station105-b, such as a downlink pathloss reference signal (e.g., an SSB) transmitted over an anchor carrier. As described with reference toFIG.2, the UE115-bmay measure a received power level (e.g., an RSRP) for the reference signal, and the UE115-bmay select the carrier for the transmission of the request for the system information based on the received power level. In some examples, the UE115-bmay compare the measured received power level of the reference signal to one or more thresholds, where receiving the indication of the configuration for the flexible cell may include receiving an indication of the one or more thresholds. In addition, the UE115-bmay select the carrier based on the comparison. The one or more thresholds may be indicated by the base station105-b(e.g., an indication of a configuration for the flexible cell may indicate the or more thresholds).

At320, the UE115-bmay transmit the request for the system information to the base station105-bvia the selected carrier. For example, the UE115-bmay transmit the request to the base station105-b(e.g., in a Msg1). In some cases, the UE115-bmay use a Msg1 to indicate a request for other system information, for example by using a particular resource to transmit the Msg1 associated with particular other system information (e.g., SIB2, SIB3) the UE115-bmay be requesting. In some cases, the resources may be indicated in information elements such as ra-PreambleStartIndex, ra-AssociationPeriodIndex, ra-ssb-OccasionMaskIndex, or any combination thereof.

At325, the UE115-bmay receive an acknowledgement for the request for the system information from the base station105-band via the selected carrier, indicating that the base station105-breceived the request. The base station105-bmay transmit the acknowledgement in a Msg2 (e.g., a MAC RAR). For example, after receiving the request for the system information from the UE115-bin the Msg1, and based on the random access resources the UE115-bused to transmit the Msg1, the base station105-bmay have information regarding which system information message the UE115-bis requesting. For example, a resource the UE115-bused to transmit the Msg1 may implicitly indicate which particular other system information (e.g., which SIB of the set of SIB2 through SIB9) the UE115-bmay be requesting. As such, based on the resource, the base station105-bmay acknowledge the request for the system information in the Msg2. In some examples, after receiving the acknowledgement for the request for the system information (e.g., Msg2), the UE115-bmay receive control messages via a PDCCH (e.g., the UE115-bmay receive a system information-radio network temporary identifier (SI-RNTI)).

Additionally or alternatively, the UE115-bmay receive the acknowledgement for the request for the system information based on a control message and a shared channel message. For example, at330, the UE115-bmay receive a control message from the base station105-bvia the selected carrier, where DCI in the control message may schedule the shared channel message and indicate a carrier for reception of the shared channel message. In some examples, the UE115-bmay receive a first indication of a first carrier for receiving a control message and a second indication of a second carrier for receiving the shared channel message scheduled by the control message. Additionally or alternatively, the UE115-bmay receive additional system information that may indicate the first carrier for receiving the control message.

At335, the UE115-bmay receive, from the base station105-b, a shared channel message (e.g., scheduled in the control message) via the carrier indicated by the corresponding DCI. In some examples, the shared channel message may include the acknowledgement for request for the system information. As described with reference toFIG.4, the UE115-bmay select the carrier for reception of the acknowledgement using other methods.

At340, the UE115-bmay receive the requested system information from the base station105-b. That is, the base station105-bmay transmit one or more system information messages to the UE115-bbased on the random access resources the UE115-bused to transmit the Msg1. In some examples, the base station105-bmay transmit other system information (e.g., system information other than an MIB or a SIB1, such as SIB2 through SIB9) in various ways. For example, the base station105-bmay periodically broadcast the other system information on a downlink shared channel, the base station105-bmay broadcast on-demand system information on a downlink shared channel, for example upon receiving a request from a UEs115in an idle state (e.g., RRC_IDLE) or an inactive state (e.g., RRC_INACTIVE), or the base station105-bmay transmit the other system information in a dedicated manner over a downlink shared channel to UEs115in a connected state (e.g., RRC_CONNECTED).

FIG.4illustrates an example of a process flow400that supports on-demand system information for flexible cells in accordance with aspects of the present disclosure. The process flow400may implement aspects of wireless communications systems100and200, or may be implemented by aspects of the wireless communications system100and200. For example, the process flow400may illustrate operations between a UE115-cand a base station105-c, which may be examples of corresponding devices described herein. In the following description of the process flow400, the operations between the UE115-cand the base station105-cmay be transmitted in a different order than the example order shown, or the operations performed by the UE115-cand the base station105-cmay be performed in different orders or at different times. Some operations may also be omitted from the process flow400, and other operations may be added to the process flow400. Further, aspects of the process flow400may be combined with aspects of the process flow300in any combination.

As described with reference toFIGS.2and3, the UE115-cmay select one or more carriers of a flexible cell for uplink transmissions and downlink reception in an on-demand system information procedure. In some cases, the UE115-cmay request system information from the base station105-cusing a CFRA procedure. In some examples, the system information may be minimum system information (e.g., an MIB, a SIB) or other system information (e.g., a SIB2).

At405, the UE115-cmay receive minimum system information (e.g., an MIB) from the base station105-c. In some examples, the base station105-cmay periodically broadcast an MIB over a broadcast channel.

At410, the UE115-cmay receive minimum system information (e.g., SIB1) from the base station105-c. In some cases, the base station105-cmay periodically broadcast a SIB1 on a downlink shared channel, or the base station105-cmay periodically transmit the SIB1 to a particular UE115(e.g., unicast). In some examples, the base station105-cmay configure the UE115-cwith dedicated random access resources for a request for system information in the SIB1 (e.g., in SI-RequestConfig within an SI-SchedulingInfo information element in the SIB1). In some cases, the UE115-cmay receive the SIB1 via a carrier of a set of carriers for the flexible cell, where the same carrier may be used to receive system information.

In some examples, the UE115-cmay use PRACH preambles configured for on-demand system information in the flexible cell. For example, at415, the UE115-cmay receive an indication of a set of random access preambles (e.g., PRACH preambles) for the UE to use for transmitting the request for the system information. Each random access preamble of the set may correspond to a respective set of system information associated with the flexible cell, and hence which random access preamble is transmitted (at420) as part of the request230may indicate which set of on-demand system information240is requested.

At420, the UE115-cmay transmit the request for the system information to the base station105-cvia a selected carrier. As described with reference toFIGS.2and3, the UE115-cmay select the carrier based on an indication from the base station105-c, a measured RSRP of a downlink pathloss reference signal, or another method. Additionally or alternatively, the request for the system information may be a PRACH preamble, where different PRACH preambles of a set of PRACH preambles may correspond to different sets of on-demand system information. For example, the UE115-cmay transmit the request for the system information based on a random access preamble of the set of random access preambles indicated at415.

At425, the UE115-cmay receive an acknowledgement (e.g., an acknowledgement235) for the request for the system information from the base station105-cand via the selected carrier, indicating that the base station105-creceived the request. The base station105-cmay transmit the acknowledgement in a Msg2 (e.g., the MAC RAR450). In some examples, the acknowledgment may be or include MAC signaling. For example, at425, the UE115-cmay receive the MAC signaling indicating a second carrier of the set of carriers for the flexible cell, where the UE115-cmay receive the requested system information via the second carrier. In some cases, the acknowledgement for the request for the system information (e.g., Msg2) may be carried in a MAC subPDU440that is received at425, and MAC subPDU440may include the acknowledgement along with a MAC RAR450, where the MAC RAR450may include an indication of the carrier that the UE115-cis to select as the selected carrier for subsequent reception of the requested system information.

Thus, a MAC RAR450may be included in a MAC subPDU440received at425, and the selected carrier via which the requested system information is to be subsequently received may be indicated by the MAC RAR450. In some cases, the MAC subPDU440may also include a MAC subheader445, and the MAC subheader445may include a random access preamble identifier (RAPID), where the RAPID may identify the random access preamble used by the UE115-cat420to transmit the Msg1 at420. In some cases, in addition to the RAPID, the MAC subheader445may include an Extension (E) field indicating whether the MAC subPDU440is the last MAC subPDU in a corresponding MAC PDU, along with a Type (T) field indicating whether the MAC subheader445includes a RAPID.

At430, the UE115-cmay receive the requested system information from the base station105-c. That is, the base station105-cmay transmit one or more system information messages to the UE115-ccorresponding to the random access resources (e.g., the random access preamble) that the UE115-cused to transmit the Msg1 at420. For example, the base station105-cmay transmit the requested system information via the second carrier, where the second carrier may have been indicated in the MAC RAR450.

FIG.5illustrates an example of a process flow500that supports on-demand system information for flexible cells in accordance with aspects of the present disclosure. The process flow500may implement aspects of wireless communications systems100and200, or may be implemented by aspects of the wireless communications system100and200. For example, the process flow500may illustrate operations between a UE115-dand a base station105-d, which may be examples of corresponding devices described herein. In the following description of the process flow500, the operations between the UE115-dand the base station105-dmay be transmitted in a different order than the example order shown, or the operations performed by the UE115-dand the base station105-dmay be performed in different orders or at different times. Some operations may also be omitted from the process flow500, and other operations may be added to the process flow500.

At505, the UE115-dmay receive, from the base station105-dan indication of a configuration for a flexible cell supported by the base station105-d. The flexile cell may include a set of carriers including an anchor carrier and two or more non-anchor carriers, which may support any combination of FDD operations, TDD operations, and SUL operations.

At510, the UE115-dmay select, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a first carrier for transmission of a request for system information associated with the flexible cell. In some examples, the UE115-dmay select the first carrier based on an indication from the base station105-d, a carrier identifier associated each carrier of the set of carriers, a measured received power level of a downlink pathloss reference signal, or any combination thereof.

At515, the UE115-dmay select, from among the set of carries of the flexible cell and based on the configuration for the flexible cell, a second carrier for reception by the UE115-dof an acknowledgement for the request for the system information associated with the flexible cell. For example, the UE115-dmay select the second carrier based on a control message, a shared channel message, a PRACH preamble, or any combination thereof.

At520, the UE115-dmay transmit the request for the system information via the selected first carrier. In some examples, the UE115-dmay transmit a random access preamble corresponding to a respective set of system information, where the request for the system information includes a request for the respective set of system information corresponding to the transmitted random access preamble.

At525, the UE115-dmay receive the acknowledgement for the request for the system information via the selected second carrier. In some examples, the UE115-dmay receive the acknowledgement in a RAR (e.g., a MAC RAR) in response to transmitting the random access preamble.

At530, after receiving the acknowledgement for the request, the UE115-dmay receive, from the base station105-d, the requested system information associated with the flexible cell via a carrier selected for the reception of the system information. The selected carrier may be the same carrier on which the UE115-dreceived the acknowledgement, a SIB (e.g., a SIB1), or an SSB.

The communications manager620, the receiver610, the transmitter615, or various combinations thereof or various components thereof may be examples of means for performing various aspects of on-demand system information for flexible cells as described herein. For example, the communications manager620, the receiver610, the transmitter615, or various combinations or components thereof may support a method for performing one or more of the functions described herein.

In some examples, the communications manager620may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the receiver610, the transmitter615, or both. For example, the communications manager620may be configured to receive or transmit messages or other signaling as described herein via the transceiver module. For example, the communications manager620may receive information from the receiver610, send information to the transmitter615, or be integrated in combination with the receiver610, the transmitter615, or both to receive information, transmit information, or perform various other operations as described herein.

The communications manager620may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager620may be configured as or otherwise support a means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The communications manager620may be configured as or otherwise support a means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell. The communications manager620may be configured as or otherwise support a means for transmitting the request for the system information via the selected carrier.

Additionally or alternatively, the communications manager620may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager620may be configured as or otherwise support a means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The communications manager620may be configured as or otherwise support a means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell. The communications manager620may be configured as or otherwise support a means for transmitting, to the base station, the request for the system information associated with the flexible cell. The communications manager620may be configured as or otherwise support a means for receiving the acknowledgement for the request for the system information via the selected carrier.

By including or configuring the communications manager620in accordance with examples as described herein, the device605(e.g., a processor controlling or otherwise coupled with the receiver610, the transmitter615, the communications manager620, or a combination thereof) may support techniques for communicating on-demand system information in a flexible cell, which may increase the efficiency and reduce latency of the communications by enabling the UE to select and be aware of a carrier for the system information communications.

The device705, or various components thereof, may be an example of means for performing various aspects of on-demand system information for flexible cells as described herein. For example, the communications manager720may include a flexible cell configuration component725, a request carrier selection component730, a request transmission component735, an acknowledgment carrier selection component740, an acknowledgement reception component745, or any combination thereof. The communications manager720may be an example of aspects of a communications manager620as described herein. In some examples, the communications manager720, or various components thereof, may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the receiver710, the transmitter715, or both. For example, the communications manager720may receive information from the receiver710, send information to the transmitter715, or be integrated in combination with the receiver710, the transmitter715, or both to receive information, transmit information, or perform various other operations as described herein.

The communications manager720may support wireless communication at a UE in accordance with examples as disclosed herein. The flexible cell configuration component725may be configured as or otherwise support a means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The request carrier selection component730may be configured as or otherwise support a means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell. The request transmission component735may be configured as or otherwise support a means for transmitting the request for the system information via the selected carrier.

Additionally or alternatively, the communications manager720may support wireless communication at a UE in accordance with examples as disclosed herein. The flexible cell configuration component725may be configured as or otherwise support a means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The acknowledgment carrier selection component740may be configured as or otherwise support a means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell. The request transmission component735may be configured as or otherwise support a means for transmitting, to the base station, the request for the system information associated with the flexible cell. The acknowledgement reception component745may be configured as or otherwise support a means for receiving the acknowledgement for the request for the system information via the selected carrier.

FIG.8shows a block diagram800of a communications manager820that supports on-demand system information for flexible cells in accordance with aspects of the present disclosure. The communications manager820may be an example of aspects of a communications manager620, a communications manager720, or both, as described herein. The communications manager820, or various components thereof, may be an example of means for performing various aspects of on-demand system information for flexible cells as described herein. For example, the communications manager820may include a flexible cell configuration component825, a request carrier selection component830, a request transmission component835, an acknowledgment carrier selection component840, an acknowledgement reception component845, a carrier identifier component850, a reference signal component855, a random access preamble component860, a control message component865, a shared channel message component870, a system information reception component875, a reference signal component880, or any combination thereof. Each of these components may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The communications manager820may support wireless communication at a UE in accordance with examples as disclosed herein. The flexible cell configuration component825may be configured as or otherwise support a means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The request carrier selection component830may be configured as or otherwise support a means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell. The request transmission component835may be configured as or otherwise support a means for transmitting the request for the system information via the selected carrier.

In some examples, to support receiving the indication of the configuration for the flexible cell, the carrier identifier component850may be configured as or otherwise support a means for receiving an indication of a set of carrier identifiers including a respective carrier identifier for each carrier of the set of carriers. In some examples, to support receiving the indication of the configuration for the flexible cell, the carrier identifier component850may be configured as or otherwise support a means for receiving an indication of the respective carrier identifier for the selected carrier, where the indication of the respective carrier identifier for the selected carrier indicates which carrier the UE is to select for transmission of the request for the system information.

In some examples, to support receiving the indication of the configuration for the flexible cell, the carrier identifier component850may be configured as or otherwise support a means for receiving RRC signaling that indicates the set of carrier identifiers, the respective carrier identifier for the selected carrier, or both.

In some examples, to support receiving the indication of the set of carrier identifiers, the carrier identifier component850may be configured as or otherwise support a means for receiving system information that indicates the set of carrier identifiers, the respective carrier identifier for the selected carrier, or both.

In some examples, the reference signal component855may be configured as or otherwise support a means for receiving a reference signal from the base station. In some examples, the reference signal component855may be configured as or otherwise support a means for measuring a received power level for the reference signal, where selecting the carrier based on the configuration for the flexible cell includes selecting the carrier for transmission of the request for the system information based on the received power level for the reference signal.

In some examples, the reference signal component880may be configured as or otherwise support a means for comparing the received power level for the reference signal to one or more thresholds, where receiving the indication of the configuration for the flexible cell includes receiving an indication of the one or more thresholds, and where selecting the carrier for transmission of the request for the system information is based on the comparing. The flexible cell configuration component825may be configured as or otherwise support a means for receiving an indication of the one or more thresholds (e.g., an indication of a configuration for the flexible cell may indicate the one or more thresholds).

In some examples, the one or more thresholds includes a single threshold, and the reference signal component855may be configured as or otherwise support a means for using the single threshold to select one of the two or more non-anchor carriers to use as an SUL carrier.

In some examples, the set of carriers includes a set of multiple subsets of one or more carriers, the set of multiple subsets corresponding to a set of multiple received power ranges that are each delimited by at least one threshold of the one or more thresholds. In some examples, comparing the received power level for the reference signal to the one or more thresholds includes determining that the received power level for the reference signal is within a first received power range of the set of multiple received power ranges. In some examples, selecting the carrier for transmission of the request for the system information includes selecting the carrier from a first subset of carriers based on the first subset of carriers corresponding to the first received power range.

In some examples, to support selecting the carrier from the first subset of carriers, the reference signal component855may be configured as or otherwise support a means for selecting a first carrier based on the first carrier being associated with a lowest carrier identifier from among one or more carrier identifiers corresponding to the first subset of carriers. In some examples, the first carrier is lower in frequency than each other carrier in the first subset of carriers.

In some examples, to support transmitting the request for the system information, the random access preamble component860may be configured as or otherwise support a means for transmitting a random access preamble via the selected carrier, where the random access preamble is one of a set of random access preambles each corresponding to a respective set of system information associated with the flexible cell, and where the request for system information associated with the flexible cell includes a request for the respective set of system information corresponding to the transmitted random access preamble.

Additionally or alternatively, the communications manager820may support wireless communication at a UE in accordance with examples as disclosed herein. In some examples, the flexible cell configuration component825may be configured as or otherwise support a means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The acknowledgment carrier selection component840may be configured as or otherwise support a means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell. In some examples, the request transmission component835may be configured as or otherwise support a means for transmitting, to the base station, the request for the system information associated with the flexible cell. The acknowledgement reception component845may be configured as or otherwise support a means for receiving the acknowledgement for the request for the system information via the selected carrier.

In some examples, to support receiving the indication of the configuration for the flexible cell, the flexible cell configuration component825may be configured as or otherwise support a means for receiving, prior to selecting the carrier, additional system information that indicates the configuration for the flexible cell.

In some examples, the additional system information includes an indication of a carrier identifier for the selected carrier. In some examples, an absence from the additional system information of an indication of a carrier identifier for the selected carrier includes an indication that the UE is to select the anchor carrier as the selected carrier.

In some examples, to support receiving the acknowledgement for the request for the system information via the selected carrier, the control message component865may be configured as or otherwise support a means for receiving a control message via the selected carrier. In some examples, to support receiving the acknowledgement for the request for the system information via the selected carrier, the shared channel message component870may be configured as or otherwise support a means for receiving a shared channel message via the selected carrier, the shared channel message scheduled by the control message and including the acknowledgement.

In some examples, to support receiving the indication of the configuration for the flexible cell, the control message component865may be configured as or otherwise support a means for receiving a first indication of a first carrier of the set of carriers, where the first carrier is for receiving a control message. In some examples, to support receiving the indication of the configuration for the flexible cell, the shared channel message component870may be configured as or otherwise support a means for receiving a second indication of a second carrier of the set of carriers, where the second carrier includes the selected carrier and is for receiving a shared channel message that is scheduled by the control message and includes the acknowledgement.

In some examples, to support receiving the indication of the configuration for the flexible cell, the control message component865may be configured as or otherwise support a means for receiving, prior to selecting the carrier, additional system information that includes the first indication of the first carrier and the second indication of the second carrier.

In some examples, to support receiving the indication of the configuration for the flexible cell, the control message component865may be configured as or otherwise support a means for receiving, prior to selecting the carrier, additional system information that includes the first indication of the first carrier. In some examples, to support receiving the indication of the configuration for the flexible cell, the control message component865may be configured as or otherwise support a means for receiving the second indication of the second carrier within the control message. In some examples, the first carrier is different than the second carrier. In some examples, the first carrier and the second carrier include a same carrier.

In some examples, to support receiving the indication of the configuration for the flexible cell, the random access preamble component860may be configured as or otherwise support a means for receiving an indication of a set of random access preambles for the UE to use for transmitting system information requests.

In some examples, the random access preamble component860may be configured as or otherwise support a means for transmitting the request for the system information associated with the flexible cell using a preamble of the set of random access preambles. In some examples, the random access preamble component860may be configured as or otherwise support a means for receiving the system information associated with the flexible cell via a second carrier of the set of carriers, where the acknowledgement for the request includes MAC signaling that indicates the second carrier.

In some examples, the system information reception component875may be configured as or otherwise support a means for receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the selected carrier.

In some examples, the system information reception component875may be configured as or otherwise support a means for receiving, prior to transmitting the request for the system information associated with the flexible cell, a first SIB via a second carrier of the set of carriers. In some examples, the system information reception component875may be configured as or otherwise support a means for receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the second carrier.

In some examples, the system information reception component875may be configured as or otherwise support a means for receiving, prior to transmitting the request for the system information associated with the flexible cell, an SSB via a second carrier of the set of carriers. In some examples, the system information reception component875may be configured as or otherwise support a means for receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the second carrier.

In some examples, transmitting the request for the system information includes transmitting a random access preamble. In some examples, receiving the acknowledgement for the request for the system information includes receiving a RAR message in response to transmitting the random access preamble.

The communications manager920may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager920may be configured as or otherwise support a means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The communications manager920may be configured as or otherwise support a means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell. The communications manager920may be configured as or otherwise support a means for transmitting the request for the system information via the selected carrier.

Additionally or alternatively, the communications manager920may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager920may be configured as or otherwise support a means for receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The communications manager920may be configured as or otherwise support a means for selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell. The communications manager920may be configured as or otherwise support a means for transmitting, to the base station, the request for the system information associated with the flexible cell. The communications manager920may be configured as or otherwise support a means for receiving the acknowledgement for the request for the system information via the selected carrier.

By including or configuring the communications manager920in accordance with examples as described herein, the device905may support techniques for communicating on-demand system information in a flexible cell, which may increase the efficiency and reduce latency of the communications by enabling the UE to select and be aware of a carrier for the system information communications.

At1005, the method may include receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The operations of1005may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1005may be performed by a flexible cell configuration component825as described with reference toFIG.8. Additionally or alternatively, means for performing1005may, but not necessarily, include, for example, an antenna925, a transceiver915, a communications manager920, a memory930(including code935), a processor940, a bus945, or any combination thereof.

At1010, the method may include selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell. The operations of1010may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1010may be performed by a request carrier selection component830as described with reference toFIG.8. Additionally or alternatively, means for performing1010may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1015, the method may include transmitting the request for the system information via the selected carrier. The operations of1015may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1015may be performed by a request transmission component835as described with reference toFIG.8. Additionally or alternatively, means for performing1015may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1105, the method may include receiving an indication of a set of carrier identifiers comprising a respective carrier identifier for each carrier of a set of carriers, wherein the set of carriers is for a flexible cell supported by a base station, and wherein the set of carriers for the flexible cell comprises an anchor carrier and two or more non-anchor carriers. The operations of1105may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1105may be performed by a carrier identifier component850as described with reference toFIG.8. Additionally or alternatively, means for performing1105may, but not necessarily, include, for example, an antenna925, a transceiver915, a communications manager920, a memory930(including code935), a processor940, a bus945, or any combination thereof.

At1110, the method may include receiving an indication of the respective carrier identifier for a carrier of the set of carriers, wherein the indication of the respective carrier identifier for the carrier indicates that the UE is to select the carrier for transmission of the request for the system information. The operations of1110may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1110may be performed by a carrier identifier component850as described with reference toFIG.8. Additionally or alternatively, means for performing1110may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1115, the method may include selecting the carrier, from among the set of carriers of the flexible cell and based on the indication of the respective carrier identifier for the carrier, for transmission of a request for system information associated with the flexible cell. The operations of1115may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1115may be performed by a request carrier selection component830as described with reference toFIG.8. Additionally or alternatively, means for performing1115may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1120, the method may include transmitting the request for the system information via the selected carrier. The operations of1120may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1120may be performed by a request transmission component835as described with reference toFIG.8. Additionally or alternatively, means for performing1120may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1205, the method may include receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The operations of1205may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1205may be performed by a flexible cell configuration component825as described with reference toFIG.8. Additionally or alternatively, means for performing1205may, but not necessarily, include, for example, an antenna925, a transceiver915, a communications manager920, a memory930(including code935), a processor940, a bus945, or any combination thereof.

At1210, the method may include receiving a reference signal from the base station. The operations of1210may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1210may be performed by a reference signal component855as described with reference toFIG.8. Additionally or alternatively, means for performing1210may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1215, the method may include measuring a received power level for the reference signal. The operations of1215may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1215may be performed by a reference signal component855as described with reference toFIG.8. Additionally or alternatively, means for performing1215may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1220, the method may include comparing the received power level for the reference signal to one or more thresholds. In some cases, receiving the indication of the configuration for the flexible cell may include receiving an indication of the one or more thresholds. The operations of1220may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1220may be performed by a reference signal component880as described with reference toFIG.8. Additionally or alternatively, means for performing1220may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1225, the method may include selecting, from among the set of carriers of the flexible cell and based on the comparing, a carrier for transmission of a request for system information associated with the flexible cell. The operations of1225may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1225may be performed by a request carrier selection component830as described with reference toFIG.8. Additionally or alternatively, means for performing1225may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1230, the method may include transmitting the request for the system information via the selected carrier. The operations of1230may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1230may be performed by a request transmission component835as described with reference toFIG.8. Additionally or alternatively, means for performing1230may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1305, the method may include receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The operations of1305may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1305may be performed by a flexible cell configuration component825as described with reference toFIG.8. Additionally or alternatively, means for performing1305may, but not necessarily, include, for example, an antenna925, a transceiver915, a communications manager920, a memory930(including code935), a processor940, a bus945, or any combination thereof.

At1310, the method may include selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell. The operations of1310may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1310may be performed by an acknowledgment carrier selection component840as described with reference toFIG.8. Additionally or alternatively, means for performing1310may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1315, the method may include transmitting, to the base station, the request for the system information associated with the flexible cell. The operations of1315may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1315may be performed by a request transmission component835as described with reference toFIG.8. Additionally or alternatively, means for performing1315may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1320, the method may include receiving the acknowledgement for the request for the system information via the selected carrier. The operations of1320may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1320may be performed by an acknowledgement reception component845as described with reference toFIG.8. Additionally or alternatively, means for performing1320may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1405, the method may include receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The operations of1405may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1405may be performed by a flexible cell configuration component825as described with reference toFIG.8. Additionally or alternatively, means for performing1405may, but not necessarily, include, for example, an antenna925, a transceiver915, a communications manager920, a memory930(including code935), a processor940, a bus945, or any combination thereof.

At1410, the method may include selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell. The operations of1410may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1410may be performed by an acknowledgment carrier selection component840as described with reference toFIG.8. Additionally or alternatively, means for performing1410may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1415, the method may include transmitting, to the base station, the request for the system information associated with the flexible cell. The operations of1415may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1415may be performed by a request transmission component835as described with reference toFIG.8. Additionally or alternatively, means for performing1415may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1420, the method may include receiving a control message via the selected carrier. The operations of1420may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1420may be performed by a control message component865as described with reference toFIG.8. Additionally or alternatively, means for performing1420may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1425, the method may include receiving a shared channel message via the selected carrier, the shared channel message scheduled by the control message and including the acknowledgement for the request for the system information. The operations of1425may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1425may be performed by a shared channel message component870as described with reference toFIG.8. Additionally or alternatively, means for performing1425may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1505, the method may include receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The operations of1505may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1505may be performed by a flexible cell configuration component825as described with reference toFIG.8. Additionally or alternatively, means for performing1505may, but not necessarily, include, for example, an antenna925, a transceiver915, a communications manager920, a memory930(including code935), a processor940, a bus945, or any combination thereof.

At1510, the method may include receiving an indication of a set of random access preambles for the UE to use for transmitting system information requests to the base station. The operations of1510may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1510may be performed by a random access preamble component860as described with reference toFIG.8. Additionally or alternatively, means for performing1510may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1515, the method may include selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell. The operations of1515may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1515may be performed by an acknowledgment carrier selection component840as described with reference toFIG.8. Additionally or alternatively, means for performing1515may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1520, the method may include transmitting, to the base station and using a preamble of the set of random access preambles, the request for the system information associated with the flexible cell. The operations of1520may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1520may be performed by a random access preamble component860as described with reference toFIG.8. Additionally or alternatively, means for performing1520may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1525, the method may include receiving the acknowledgement for the request for the system information via the selected carrier. The operations of1525may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1525may be performed by an acknowledgement reception component845as described with reference toFIG.8. Additionally or alternatively, means for performing1525may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1530, the method may include receiving the system information associated with the flexible cell via a second carrier of the set of carriers, where the acknowledgement for the request includes MAC signaling that indicates the second carrier. The operations of1530may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1530may be performed by a random access preamble component860as described with reference toFIG.8. Additionally or alternatively, means for performing1530may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1605, the method may include receiving an indication of a configuration for a flexible cell supported by a base station, where the flexible cell includes a set of carriers including an anchor carrier and two or more non-anchor carriers. The operations of1605may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1605may be performed by a flexible cell configuration component825as described with reference toFIG.8. Additionally or alternatively, means for performing1605may, but not necessarily, include, for example, an antenna925, a transceiver915, a communications manager920, a memory930(including code935), a processor940, a bus945, or any combination thereof.

At1610, the method may include selecting, from among the set of carriers of the flexible cell and based on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell. The operations of1610may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1610may be performed by an acknowledgment carrier selection component840as described with reference toFIG.8. Additionally or alternatively, means for performing1610may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1615, the method may include transmitting, to the base station, the request for the system information associated with the flexible cell. The operations of1615may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1615may be performed by a request transmission component835as described with reference toFIG.8. Additionally or alternatively, means for performing1615may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1620, the method may include receiving the acknowledgement for the request for the system information via the selected carrier. The operations of1620may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1620may be performed by an acknowledgement reception component845as described with reference toFIG.8. Additionally or alternatively, means for performing1620may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

At1625, the method may include receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the selected carrier. The operations of1625may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of1625may be performed by a system information reception component875as described with reference toFIG.8. Additionally or alternatively, means for performing1625may, but not necessarily, include, for example, the antenna925, the transceiver915, the communications manager920, the memory930(including code935), the processor940, the bus945, or any combination thereof.

Aspect 1: A method for wireless communication at a UE, comprising: receiving an indication of a configuration for a flexible cell supported by a base station, wherein the flexible cell comprises a set of carriers comprising an anchor carrier and two or more non-anchor carriers; selecting, from among the set of carriers of the flexible cell and based at least in part on the configuration for the flexible cell, a carrier for transmission of a request for system information associated with the flexible cell; and transmitting the request for the system information via the selected carrier.

Aspect 2: The method of aspect 1, wherein receiving the indication of the configuration for the flexible cell comprises: receiving an indication of a set of carrier identifiers comprising a respective carrier identifier for each carrier of the set of carriers; and receiving an indication of the respective carrier identifier for the selected carrier, wherein the indication of the respective carrier identifier for the selected carrier indicates which carrier the UE is to select for transmission of the request for the system information.

Aspect 3: The method of aspect 2, wherein receiving the indication of the configuration for the flexible cell comprises: receiving RRC signaling that indicates the set of carrier identifiers, the respective carrier identifier for the selected carrier, or both.

Aspect 4: The method of any of aspects 2 through 3, wherein receiving the indication of the set of carrier identifiers comprises: receiving system information that indicates the set of carrier identifiers, the respective carrier identifier for the selected carrier, or both.

Aspect 5: The method of any of aspects 1 through 4, further comprising: receiving a reference signal from the base station; and measuring a received power level for the reference signal, wherein selecting the carrier based at least in part on the configuration for the flexible cell comprises selecting the carrier for transmission of the request for the system information based at least in part on the received power level for the reference signal.

Aspect 6: The method of aspect 5, further comprising: comparing the received power level for the reference signal to one or more thresholds, wherein receiving the indication of the configuration for the flexible cell comprises receiving an indication of the one or more thresholds, and wherein selecting the carrier for transmission of the request for the system information is based at least in part on the comparing.

Aspect 7: The method of aspect 6, wherein the one or more thresholds comprises a single threshold, the method further comprising: using the single threshold to select one of the two or more non-anchor carriers to use as an SUL carrier.

Aspect 8: The method of any of aspects 6 through 7, wherein the set of carriers comprises a plurality of subsets of one or more carriers, the plurality of subsets corresponding to a plurality of received power ranges that are each delimited by at least one threshold of the one or more thresholds; comparing the received power level for the reference signal to the one or more thresholds comprises determining that the received power level for the reference signal is within a first received power range of the plurality of received power ranges; and selecting the carrier for transmission of the request for the system information comprises selecting the carrier from a first subset of carriers based at least in part on the first subset of carriers corresponding to the first received power range.

Aspect 9: The method of aspect 8, wherein selecting the carrier from the first subset of carriers comprises: selecting a first carrier based at least in part on the first carrier being associated with a lowest carrier identifier from among one or more carrier identifiers corresponding to the first subset of carriers.

Aspect 10: The method of aspect 9, wherein the first carrier is lower in frequency than each other carrier in the first subset of carriers.

Aspect 11: The method of any of aspects 1 through 10, wherein transmitting the request for the system information comprises: transmitting a random access preamble via the selected carrier, wherein the random access preamble is one of a set of random access preambles each corresponding to a respective set of system information associated with the flexible cell, and wherein the request for system information associated with the flexible cell comprises a request for the respective set of system information corresponding to the transmitted random access preamble.

Aspect 12: A method for wireless communication at a UE, comprising: receiving an indication of a configuration for a flexible cell supported by a base station, wherein the flexible cell comprises a set of carriers comprising an anchor carrier and two or more non-anchor carriers; selecting, from among the set of carriers of the flexible cell and based at least in part on the configuration for the flexible cell, a carrier for reception by the UE of an acknowledgement for a request for system information associated with the flexible cell; transmitting, to the base station, the request for the system information associated with the flexible cell; and receiving the acknowledgement for the request for the system information via the selected carrier.

Aspect 13: The method of aspect 12, wherein receiving the indication of the configuration for the flexible cell comprises: receiving, prior to selecting the carrier, additional system information that indicates the configuration for the flexible cell.

Aspect 14: The method of aspect 13, wherein the additional system information comprises an indication of a carrier identifier for the selected carrier.

Aspect 15: The method of any of aspects 13 through 14, wherein an absence from the additional system information of an indication of a carrier identifier for the selected carrier comprises an indication that the UE is to select the anchor carrier as the selected carrier.

Aspect 16: The method of any of aspects 13 through 15, wherein receiving the acknowledgement for the request for the system information via the selected carrier comprises: receiving a control message via the selected carrier; and receiving a shared channel message via the selected carrier, the shared channel message scheduled by the control message and comprising the acknowledgement.

Aspect 17: The method of any of aspects 12 through 16, wherein receiving the indication of the configuration for the flexible cell comprises receiving a first indication of a first carrier of the set of carriers, wherein the first carrier is for receiving a control message, the method further comprising receiving a second indication of a second carrier of the set of carriers, wherein the second carrier comprises the selected carrier and is for receiving a shared channel message that is scheduled by the control message and comprises the acknowledgement.

Aspect 18: The method of aspect 17, wherein receiving the indication of the configuration for the flexible cell comprises: receiving, prior to selecting the carrier, additional system information that comprises the first indication of the first carrier and the second indication of the second carrier.

Aspect 19: The method of any of aspects 17 through 18, wherein receiving the indication of the configuration for the flexible cell comprises: receiving, prior to selecting the carrier, additional system information that comprises the first indication of the first carrier; and receiving the second indication of the second carrier within the control message.

Aspect 20: The method of any of aspects 17 through 19, wherein the first carrier is different than the second carrier.

Aspect 21: The method of any of aspects 17 through 20, wherein the first carrier and the second carrier comprise a same carrier.

Aspect 22: The method of any of aspects 12 through 21, wherein receiving the indication of the configuration for the flexible cell comprises: receiving an indication of a set of random access preambles for the UE to use for transmitting system information requests.

Aspect 23: The method of aspect 22, wherein the request for the system information associated with the flexible cell is transmitted using a preamble of the set of random access preambles, the method further comprising: receiving the system information associated with the flexible cell via a second carrier of the set of carriers, wherein the acknowledgement for the request comprises MAC signaling that indicates the second carrier.

Aspect 24: The method of any of aspects 12 through 23, further comprising: receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the selected carrier.

Aspect 25: The method of any of aspects 12 through 24, further comprising: receiving, prior to transmitting the request for the system information associated with the flexible cell, a first SIB via a second carrier of the set of carriers; and receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the second carrier.

Aspect 26: The method of any of aspects 12 through 25, further comprising: receiving, prior to transmitting the request for the system information associated with the flexible cell, an SSB via a second carrier of the set of carriers; and receiving, after receiving the acknowledgement for the request via the selected carrier, the system information associated with the flexible cell via the second carrier.

Aspect 27: The method of any of aspects 12 through 26, wherein transmitting the request for the system information comprises transmitting a random access preamble; and receiving the acknowledgement for the request for the system information comprises receiving a RAR message in response to transmitting the random access preamble.

Aspect 28: An apparatus for wireless communication at a UE, comprising memory, a transceiver, and at least one processor of a UE, the at least one processor coupled with the memory and the transceiver, and the at least one processor configured to cause the apparatus to perform a method of any of aspects 1 through 11.

Aspect 31: An apparatus for wireless communication at a UE, comprising memory, a transceiver, and at least one processor of a UE, the at least one processor coupled with the memory and the transceiver, and the at least one processor configured to cause the apparatus to perform a method of any of aspects 12 through 27.

Aspect 32: An apparatus for wireless communication at a UE, comprising at least one means for performing a method of any of aspects 12 through 27.