DOWNLINK INITIAL ACCESS SIGNAL TO RANDOM ACCESS CHANNEL OCCASION ASSOCIATION

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a base station, configuration information indicating a downlink initial access signal (IAS) to random access channel (RACH) occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions. The UE may transmit, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern. Numerous other aspects are described.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for downlink initial access signal (IAS) to random access channel (RACH) occasion association.

BACKGROUND

SUMMARY

In some aspects, a user equipment (UE) for wireless communication includes a memory and one or more processors, coupled to the memory, configured to: receive, from a base station, configuration information indicating a downlink initial access signal (IAS) to random access channel (RACH) occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and transmit, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

In some aspects, a base station for wireless communication includes a memory and one or more processors, coupled to the memory, configured to: transmit, to one or more UEs, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and receive, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

In some aspects, a method of wireless communication performed by a UE includes receiving, from a base station, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and transmitting, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

In some aspects, a method of wireless communication performed by a base station includes transmitting, to one or more UEs, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and receiving, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a UE, cause the UE to: receive, from a base station, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and transmit, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

In some aspects, a non-transitory computer-readable medium storing a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a base station, cause the base station to: transmit, to one or more UEs, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and receive, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

In some aspects, an apparatus for wireless communication includes means for receiving, from a base station, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and means for transmitting, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

In some aspects, an apparatus for wireless communication includes means for transmitting, to one or more UEs, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and means for receiving, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

DETAILED DESCRIPTION

In some aspects, the UE120includes means for receiving, from a base station, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282); and/or means for transmitting, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern (e.g., using controller/processor280, transmit processor264, TX MIMO processor266, MOD254, antenna252, and/or memory282). The means for the UE120to perform operations described herein may include, for example, one or more of antenna252, demodulator254, MIMO detector256, receive processor258, transmit processor264, TX MIMO processor266, modulator254, controller/processor280, or memory282.

In some aspects, the UE120includes means for receiving an indication that the downlink IAS to RACH occasion association pattern includes a group of downlink IAS occasions for different beams associated with the base station and a group of RACH occasions associated with the group of downlink IAS occasions, wherein the group of downlink IAS occasions are grouped together in a time domain and the group of RACH occasions are grouped together in the time domain (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the UE120includes means for receiving an indication that the downlink IAS to RACH occasion association pattern includes a downlink IAS associated with a beam grouped with a RACH occasion associated with the beam in a time domain (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the UE120includes means for receiving an indication that the downlink IAS and the RACH occasion are multiplexed in at least one of the time domain or a frequency domain (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the UE120includes means for receiving an indication of a downlink/uplink switching gap between the downlink IAS and the RACH occasion (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the UE120includes means for receiving an indication that the downlink IAS to RACH occasion association pattern includes a first order of RACH occasions in a time domain for a first association period and a second order of RACH occasions in the time domain for a second association period (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the UE120includes means for receiving an indication that the downlink IAS to RACH occasion association pattern includes a first downlink IAS associated with a first number of RACH occasions and a second downlink IAS associated with a second number of RACH occasions (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the UE120includes means for receiving an indication that the downlink IAS to RACH occasion association pattern includes a first RACH occasion frequency division multiplexed with a second RACH occasion and a guard band included between the first RACH occasion and the second RACH occasion in a frequency domain (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the UE120includes means for receiving an indication that the downlink IAS to RACH occasion association pattern is associated with a single carrier waveform type (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the UE120includes means for receiving an indication that the switching gaps include at least one of downlink to uplink switching gaps or beam switching gaps, wherein a switching gap includes: an explicit switching gap, a switching gap included in a cyclic prefix, a sub-symbol switching gap, an extended guard period switching gap, or any combination thereof (e.g., using antenna252, DEMOD254, MIMO detector256, receive processor258, controller/processor280, and/or memory282).

In some aspects, the base station110includes means for transmitting, to one or more UEs, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242); and/or means for receiving, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern (e.g., using antenna234, DEMOD232, MIMO detector236, receive processor238, controller/processor240, and/or memory242). The means for the base station110to perform operations described herein may include, for example, one or more of transmit processor220, TX MIMO processor230, modulator232, antenna234, demodulator232, MIMO detector236, receive processor238, controller/processor240, memory242, or scheduler246.

In some aspects, the base station110includes means for transmitting an indication that the downlink IAS to RACH occasion association pattern includes a group of downlink IAS occasions for different beams associated with the base station and a group of RACH occasions associated with the group of downlink IAS occasions, wherein the group of downlink IAS occasions are grouped together in a time domain and the group of RACH occasions are grouped together in the time domain (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for transmitting an indication that the downlink IAS to RACH occasion association pattern includes a downlink IAS associated with a beam grouped with a RACH occasion associated with the beam in a time domain (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for transmitting an indication that the downlink IAS and the RACH occasion are multiplexed in at least one of the time domain or a frequency domain (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for transmitting an indication of a downlink/uplink switching gap between the downlink IAS and the RACH occasion (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for determining the downlink IAS to RACH occasion association pattern based at least in part on: a length of a downlink to uplink switching time of the base station, a length of a beam switching time of the base station, a number of downlink IAS occasions associated with the downlink IAS to RACH occasion association pattern, an amount of time associated with channel acquisition for the UE, or any combination thereof (e.g., using controller/processor240and/or memory242).

In some aspects, the base station110includes means for determining whether the downlink IAS to RACH occasion association pattern includes: downlink IASs grouped together and RACH occasions group together, or downlink IASs and RACH occasions associated with a same beam grouped together (e.g., using controller/processor240and/or memory242).

In some aspects, the base station110includes means for transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first order of RACH occasions in a time domain for a first association period and a second order of RACH occasions in the time domain for a second association period (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first downlink IAS associated with a first number of RACH occasions and a second downlink IAS associated with a second number of RACH occasions (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first RACH occasion frequency division multiplexed with a second RACH occasion and a guard band included between the first RACH occasion and the second RACH occasion in a frequency domain (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for filtering a frequency domain resource allocation associated with the RACH occasion used to transmit the RACH message (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242); and/or means for applying single carrier processing for the frequency domain resource allocation associated with the RACH occasion used to transmit the RACH message (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for transmitting an indication that the downlink IAS to RACH occasion association pattern is associated with a single carrier waveform type (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

In some aspects, the base station110includes means for transmitting an indication that the switching gaps include at least one of downlink to uplink switching gaps or beam switching gaps, wherein a switching gap includes: an explicit switching gap, a switching gap included in a cyclic prefix, a sub-symbol switching gap, an extended guard period switching gap, or any combination thereof (e.g., using controller/processor240, transmit processor220, TX MIMO processor230, MOD232, antenna234, and/or memory242).

FIG. 3is a diagram illustrating an example300of a synchronization signal (SS) hierarchy, in accordance with the present disclosure. As shown inFIG. 3, the SS hierarchy may include an SS burst set305, which may include multiple SS bursts310, shown as SS burst 0 through SS burst N−1, where Nis a maximum number of repetitions of the SS burst310that may be transmitted by the base station. As further shown, each SS burst310may include one or more SS blocks (SSBs)315, shown as SSB 0 through SSB M−1, where M is a maximum number of SSBs315that can be carried by an SS burst310. In some aspects, different SSBs315may be beam-formed differently (e.g., transmitted using different beams), and may be used for cell search, cell acquisition, beam management, and/or beam selection (e.g., as part of an initial network access procedure). An SS burst set305may be periodically transmitted by a wireless node (e.g., base station110), such as every X milliseconds, as shown inFIG. 3. In some aspects, an SS burst set305may have a fixed or dynamic length, shown as Y milliseconds inFIG. 3. In some cases, an SS burst set305or an SS burst310may be referred to as a discovery reference signal (DRS) transmission window or an SSB measurement time configuration (SMTC) window.

In some aspects, an SSB315may include resources that carry a primary synchronization signal (PSS)320, a secondary synchronization signal (SSS)325, and/or a physical broadcast channel (PBCH)330. In some aspects, multiple SSBs315are included in an SS burst310(e.g., with transmission on different beams), and the PSS320, the SSS325, and/or the PBCH330may be the same across each SSB315of the SS burst310. In some aspects, a single SSB315may be included in an SS burst310. In some aspects, the SSB315may be at least four symbols (e.g., OFDM symbols) in length, where each symbol carries one or more of the PSS320(e.g., occupying one symbol), the SSS325(e.g., occupying one symbol), and/or the PBCH330(e.g., occupying two symbols). In some aspects, an SSB315may be referred to as an SS/PBCH block.

In some aspects, the symbols of an SSB315are consecutive, as shown inFIG. 3. In some aspects, the symbols of an SSB315are non-consecutive. Similarly, in some aspects, one or more SSBs315of the SS burst310may be transmitted in consecutive radio resources (e.g., consecutive symbols) during one or more slots. Additionally, or alternatively, one or more SSBs315of the SS burst310may be transmitted in non-consecutive radio resources.

In some aspects, the SS bursts310may have a burst period, and the SSBs315of the SS burst310may be transmitted by a wireless node (e.g., base station110) according to the burst period. In this case, the SSBs315may be repeated during each SS burst310. In some aspects, the SS burst set305may have a burst set periodicity, whereby the SS bursts310of the SS burst set305are transmitted by the wireless node according to the fixed burst set periodicity. In other words, the SS bursts310may be repeated during each SS burst set305.

In some aspects, an SSB315may include an SSB index, which may correspond to a beam used to carry the SSB315. A UE120may monitor for and/or measure SSBs315using different receive (Rx) beams during an initial network access procedure and/or a cell search procedure, among other examples. For example, the UE120may monitor for and/or measure SSBs315using different Rx beams during a random access procedure to identify a RACH occasion to use to transmit a RACH occasion (e.g., as described in more detail below). Based at least in part on the monitoring and/or measuring, the UE120may indicate one or more SSBs315with a best signal parameter (e.g., a reference signal received power (RSRP) parameter) to a base station110. The base station110and the UE120may use the one or more indicated SSBs315to select one or more beams to be used for communication between the base station110and the UE120(e.g., for a RACH procedure). Additionally, or alternatively, the UE120may use the SSB315and/or the SSB index to determine a cell timing for a cell via which the SSB315is received (e.g., a serving cell).

As indicated above,FIG. 3is provided as an example. Other examples may differ from what is described with regard toFIG. 3.

FIG. 4is a diagram illustrating an example400of a two-step random access procedure, in accordance with the present disclosure. As shown inFIG. 4, a base station110and a UE120may communicate with one another to perform the two-step random access procedure (e.g., a two-step RACH procedure).

As shown by reference number405, the base station110may transmit, and the UE120may receive, one or more SSBs and random access configuration information. In some aspects, the random access configuration information may be transmitted in and/or indicated by system information (e.g., in one or more system information blocks (SIBs)) and/or an SSB, such as for contention-based random access. Additionally, or alternatively, the random access configuration information may be transmitted in a radio resource control (RRC) message and/or a physical downlink control channel (PDCCH) order message that triggers a RACH procedure, such as for contention-free random access. The random access configuration information may include one or more parameters to be used in the two-step random access procedure, such as one or more parameters for transmitting a random access message (RAM) and/or receiving a random access response (RAR) to the RAM.

As shown by reference number410, the UE120may transmit, and the base station110may receive, a RAM preamble. As shown by reference number415, the UE120may transmit, and the base station110may receive, a RAM payload. In some aspects, the UE120may transmit the RAM preamble and the RAM payload to the base station110in a RACH occasion indicated by, or associated with, an SSB transmitted by the base station110. “RACH occasion” may refer to a set of resources (e.g., frequency resources and/or time resources) and/or a transmission opportunity for the UE120associated with a RACH procedure. As shown, the UE120may transmit the RAM preamble and the RAM payload to the base station110as part of an initial (or first) step of the two-step random access procedure. In some aspects, the RAM may be referred to as message A, msgA, a first message, or an initial message in a two-step random access procedure. Furthermore, in some aspects, the RAM preamble may be referred to as a message A preamble, a msgA preamble, a preamble, or a physical random access channel (PRACH) preamble, and the RAM payload may be referred to as a message A payload, a msgA payload, or a payload. In some aspects, the RAM may include some or all of the contents of message 1 (msg1) and message 3 (msg3) of a four-step random access procedure, which is described in more detail below. For example, the RAM preamble may include some or all contents of message 1 (e.g., a PRACH preamble), and the RAM payload may include some or all contents of message 3 (e.g., a UE identifier, uplink control information (UCI), and/or a physical uplink shared channel (PUSCH) transmission).

As shown by reference number420, the base station110may receive the RAM preamble transmitted by the UE120. If the base station110successfully receives and decodes the RAM preamble, the base station110may then receive and decode the RAM payload.

As shown by reference number425, the base station110may transmit an RAR (sometimes referred to as an RAR message). As shown, the base station110may transmit the RAR message as part of a second step of the two-step random access procedure. In some aspects, the RAR message may be referred to as message B, msgB, or a second message in a two-step random access procedure. The RAR message may include some or all of the contents of message 2 (msg2) and message 4 (msg4) of a four-step random access procedure. For example, the RAR message may include the detected PRACH preamble identifier, the detected UE identifier, a timing advance value, and/or contention resolution information.

As shown by reference number430, as part of the second step of the two-step random access procedure, the base station110may transmit a physical downlink control channel (PDCCH) communication for the RAR. The PDCCH communication may schedule a physical downlink shared channel (PDSCH) communication that includes the RAR. For example, the PDCCH communication may indicate a resource allocation (e.g., in downlink control information (DCI)) for the PDSCH communication.

As shown by reference number435, as part of the second step of the two-step random access procedure, the base station110may transmit the PDSCH communication for the RAR, as scheduled by the PDCCH communication. The RAR may be included in a medium access control (MAC) protocol data unit (PDU) of the PDSCH communication. As shown by reference number440, if the UE120successfully receives the RAR, the UE120may transmit a hybrid automatic repeat request (HARQ) acknowledgement (ACK).

As indicated above,FIG. 4is provided as an example. Other examples may differ from what is described with regard toFIG. 4.

FIG. 5is a diagram illustrating an example500of a four-step random access procedure, in accordance with the present disclosure. As shown inFIG. 5, a base station110and a UE120may communicate with one another to perform the four-step random access procedure.

As shown by reference number505, the base station110may transmit, and the UE120may receive, one or more SSBs and random access configuration information. In some aspects, the random access configuration information may be transmitted in and/or indicated by system information (e.g., in one or more system information blocks (SIBs)) and/or an SSB, such as for contention-based random access. Additionally, or alternatively, the random access configuration information may be transmitted in a radio resource control (RRC) message and/or a physical downlink control channel (PDCCH) order message that triggers a RACH procedure, such as for contention-free random access. The random access configuration information may include one or more parameters to be used in the random access procedure, such as one or more parameters for transmitting a RAM and/or one or more parameters for receiving an RAR.

As shown by reference number510, the UE120may transmit a RAM, which may include a preamble (sometimes referred to as a random access preamble, a PRACH preamble, or a RAM preamble). In some aspects, the UE120may transmit the RAM to the base station110in a RACH occasion indicated by, or associated with, an SSB transmitted by the base station110. The message that includes the preamble may be referred to as a message 1, msg1, MSG1, a first message, or an initial message in a four-step random access procedure. The random access message may include a random access preamble identifier.

As shown by reference number515, the base station110may transmit an RAR as a reply to the preamble. The message that includes the RAR may be referred to as message 2, msg2, MSG2, or a second message in a four-step random access procedure. In some aspects, the RAR may indicate the detected random access preamble identifier (e.g., received from the UE120in msg1). Additionally, or alternatively, the RAR may indicate a resource allocation to be used by the UE120to transmit message 3 (msg3).

In some aspects, as part of the second step of the four-step random access procedure, the base station110may transmit a PDCCH communication for the RAR. The PDCCH communication may schedule a PDSCH communication that includes the RAR. For example, the PDCCH communication may indicate a resource allocation for the PDSCH communication. Also as part of the second step of the four-step random access procedure, the base station110may transmit the PDSCH communication for the RAR, as scheduled by the PDCCH communication. The RAR may be included in a MAC PDU of the PDSCH communication.

As shown by reference number520, the UE120may transmit an RRC connection request message. The RRC connection request message may be referred to as message 3, msg3, MSG3, or a third message of a four-step random access procedure. In some aspects, the RRC connection request may include a UE identifier, UCI, and/or a PUSCH communication (e.g., an RRC connection request).

As shown by reference number525, the base station110may transmit an RRC connection setup message. The RRC connection setup message may be referred to as message 4, msg4, MSG4, or a fourth message of a four-step random access procedure. In some aspects, the RRC connection setup message may include the detected UE identifier, a timing advance value, and/or contention resolution information. As shown by reference number530, if the UE120successfully receives the RRC connection setup message, the UE120may transmit a HARQ ACK.

As indicated above,FIG. 5is provided as an example. Other examples may differ from what is described with regard toFIG. 5.

FIGS. 6A and 6Bare diagrams illustrating an example600of SSB to RACH occasion association, in accordance with the present disclosure. As described above, a UE120may transmit a PRACH message (e.g., a msgA and/or a msg1) using a RACH occasion. The RACH occasion may be a set of time domain and frequency domain resources that are available for the UE120to transmit the PRACH message. RACH occasions may be mapped to SSBs (e.g., to SSB indexes) to enable a base station110to associate preambles included in a PRACH transmission (e.g., transmitted in a RACH occasion) to SSB beams. The base station110may signal, to the UE120, an SSB to RACH occasion association or mapping in an SIB, such as SIB 1 (e.g., SIB 1 as defined, or otherwise fixed, by the 3GPP).

For example, as shown inFIG. 6A, the base station110may transmit a first SSB605(e.g., SSB 1) using a first beam, may transmit a second SSB610(e.g., SSB 2) using a second beam, and/or may transmit a third SSB615(e.g., SSB 3) using a third beam. As shown by reference number620, a first set (e.g., one or more) of RACH occasions (ROs) may be mapped to, or associated with, the first SSB605(e.g., may be mapped to, or associated with, an index of the first SSB605). As shown by reference number625, a second set (e.g., one or more) of RACH occasions may be mapped to, or associated with, the second SSB610(e.g., may be mapped to, or associated with, an index of the second SSB610). As shown by reference number630, a third set (e.g., one or more) of RACH occasions may be mapped to, or associated with, the third SSB615(e.g., may be mapped to, or associated with, an index of the third SSB615).

As shown by reference numbers635and640, multiple RACH occasions may be configured in a single RACH slot (e.g., a time slot associated with RACH transmission opportunities). For example, as shown by reference number635, four RACH occasions associated with the first SSB605and two RACH occasions associated with the second SSB610may be included in a first RACH slot. As shown by reference number640, two RACH occasions associated with the second SSB610and four RACH occasions associated with the third SSB615may be included in a second RACH slot. Each SSB transmitted by the base station110may be associated with a set (e.g., the same number) of RACH occasions. For example, as shown inFIG. 6A, each SSB may be associated with four RACH occasions (e.g., a one SSB to four RACH occasions association or mapping). In some aspects, each SSB may be associated with a different number of RACH occasions, such as one, two, six, eight, and/or sixteen, among other examples.

In some aspects, a single RACH occasion may be associated with more than one SSB (e.g., more than one SSB index). In that case, the SSBs may be mapped to the RACH occasions first in the code domain. For example, a first SSB may be mapped to the RACH occasion and associated with a first sequence (e.g., a Zadoff-Chu sequence, a pseudo-noise sequence, and/or an orthogonal cover code) and a second SSB may be mapped to the RACH occasion and associated with a second sequence (e.g., to enable the base station110to identify the SSB beam by the sequence used to transmit the PRACH transmission in the RACH occasion).

In some aspects, for a mapping cycle or an association period, RACH occasions may be mapped consecutively to corresponding SSB indexes. SSB indexes may be mapped first in increasing order of preamble indexes within a single RACH occasion in the code domain (e.g., where multiple SSBs are to be mapped to a single RACH occasion), second in increasing order of frequency resource indexes for frequency multiplexed RACH occasions, third in increasing order of time resource indexes for time multiplexed RACH occasions within a RACH slot, and fourth in increased order of indexes for RACH slots.

The UE120may receive an SSB (e.g., the first SSB605, the second SSB610, and/or the third SSB615) and may determine that the SSB is an acceptable SSB to initiate a RACH procedure (e.g., based on a measurement of the SSB beam). The UE120may select a RACH occasion mapped to, or associated with, the SSB (e.g., the SSB index). Where the SSB is mapped to, or associated with, more than one RACH occasion, the UE120may randomly select a RACH occasion with equal probability among the multiple RACH occasions mapped to, or associated with, the SSB. The UE120may use the selected RACH occasion to transmit a PRACH message (e.g., a msgA and/or a msg1) to initiate a RACH procedure with the base station110.

As shown inFIG. 6B, the base station110may be required to switch between different beams for different RACH occasions. For example, as described above, a first RACH occasion645may be associated with a first SSB (e.g., the first SSB605) and a first beam. A second RACH occasion650may be associated with a second SSB (e.g., the second SSB610) and a second beam. As shown inFIG. 6B, each of the first RACH occasion645and the second RACH occasion650include a guard period. The guard period represents a time domain guard period that is included (e.g., at the end of the time domain resource allocation associated with a RACH occasion and/or after a time domain resource allocation of a symbol) to allow for signals from different UEs to arrive at the base station110at different times without inter-symbol interference between the adjacent symbols of the two different RACH occasions. During the guard period, the base station110is capable of monitoring and/or receiving signals, as the base station110may receive RACH messages from different UEs at different times. Although the example ofFIG. 6Bis discussed in the context of a first RACH occasion645being associated with a first beam and the second RACH occasion650being associated with a second beam, more generally, a guard period is placed at the end of any RACH occasion, whether the subsequent RACH occasion is on a same beam or a different beam. In a case where the first RACH occasion645is associated with a first beam and the second RACH occasion650is associated with a second beam, it is understood that the base station110may be required to switch between communicating, or monitoring for communications, using the first beam, to communicating, or monitoring for communications, using the second beam when transitioning from the first RACH occasion645to the second RACH occasion650. As shown inFIG. 6B, a RACH message transmitted using a RACH occasion may include a cyclic prefix (CP). As shown inFIG. 6B, in addition to the guard period, a CP may be used for a communication to further avoid inter-symbol interference (ISI) between adjacent OFDM symbols in multipath channel environments and also to simplify frequency domain processing. A CP may be a time domain guard period that is placed at the start of a RACH occasion. In some cases, a CP may be referred to as a guard interval (GI), or a GI may be used instead of a CP. As shown by reference number655, when the CP duration is longer than the time needed for beam switching, an amount of time required for the base station110to switch beams (e.g., from the first beam to the second beam) may be absorbed by a CP. Therefore, a communication performance of the RACH messages may not be impacted as the base station110may be enabled to switch beams during the time associated with the CP and receive the symbols associated with the RACH message on the second beam (e.g., during the second RACH occasion650).

As indicated above,FIGS. 6A and 6Bare provided as examples. Other examples may differ from what is described with regard toFIGS. 6A and 6B.

Some communication systems may use a single-carrier (SC) waveform in order to reduce peak-to-average power ratio (PAPR), which reduces the required power amplifier (PA) back-off for transmission of the waveform. A lower PA back off leads to improved transmission performance and improves utilization of transmit power budget. Examples of SC waveforms include DFT-S-OFDM waveforms and SC quadrature amplitude modulation (SC-QAM) waveforms.

Some NR frequency bands may operate using an OFDM waveform for downlink communications and may operate using either the OFDM waveform or an SC waveform for uplink communications. The OFDM waveform may use a CP, and in such cases may be referred to as a CP-OFDM waveform. The OFDM waveform may provide a relatively high signal-to-noise ratio (SNR), a relatively high spectral efficiency, and/or a relatively high order single user and/or multi-user MIMO (e.g., as compared to the SC waveform). An SC waveform may provide a relatively low PAPR for better coverage and/or a relatively low complexity for reception and transmission (e.g., as compared to the OFDM waveform). The SC waveform may include, for example, a single carrier time domain (SC-TD) waveform (e.g., an SC-QAM waveform) or a single carrier frequency domain (SC-FD) waveform (e.g., a DFT-s-OFDM waveform).

NR may include other frequency ranges in which an SC waveform may also be used for downlink communications to improve PAPR and reduce complexity. The SC waveform may include an SC-TD waveform or an SC-FD waveform to achieve different performance tradeoffs. For example, single carrier waveforms may provide a low PAPR, thereby improving wireless communication performance and coverage.

However, single carrier waveforms may not provide support for MIMO operations and/or frequency division multiplex (FDM) operations. For example, an SC-QAM waveform may provide a reduced complexity, as compared to a frequency domain implementation waveform, such as DFT-s-OFDM waveforms and/or OFDM waveforms, as fast Fourier transform (FFT) and inverse FFT (iFFT) operations may not be required. However, an SC-QAM waveform may be suboptimal for FDM operations and/or MIMO operations. Frequency domain implementation waveforms, such as DFT-s-OFDM waveforms and/or OFDM waveforms, may provide efficient bandwidth utilization as guard bands (e.g., a range of frequency resources that are not used) may not be required between bandwidth parts, for example. Additionally, frequency domain equalization may provide a lower complexity than time domain equalization (e.g., that may be required for time domain implementation waveforms, such as SC-QAM waveforms). In some cases, an OFDM waveform may be associated with higher PAPR and/or a high SNR. Additionally, the OFDM waveform may be associated with higher spectral efficiency and/or may support a higher order MIMO operation. As a result, an OFDM waveform may be capable of supporting high data rates.

Therefore, in some wireless networks, different types of waveforms may be used by UEs and/or base stations. As described above, SC waveforms may be used in some higher band operations. SC waveforms may be time division multiplex (TDM) based waveforms as FDM operations may be difficult or complex to perform for SC waveforms as compared to OFDM waveforms. As a result, a UE and/or a base station that is communicating using an SC waveform may be unable to use an SSB to RACH occasion mapping or associations that include RACH occasions that are frequency division multiplexed.

Moreover, for wireless communication in higher frequency bands, a larger subcarrier spacing (SCS) (e.g., 960 kHz, 1.92 MHz, and/or 3.84 MHz) may be used as compared to lower frequency bands (such as FR 1 and FR 2, which may use an SCS of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and/or 240 kHz). The larger SCS may be needed in higher frequency bands to support a larger bandwidth with the same fast Fourier transform (FFT) size as lower frequency bands. However, as a size of the SCS increases, a CP duration and a symbol duration may decrease proportionally (e.g., as a duration of a CP may be 1/SCS). Accordingly, although the short PRACH preamble formats can generally be proportionately scaled according to the subcarrier spacing (e.g., where a larger subcarrier spacing generally leads to a shorter symbol duration), scaling at the larger SCSs expected to be used in higher frequency bands may significantly reduce the cyclic prefix duration and therefore the supportable cell size. For example, for an SCS of 960 kHz, a CP duration may be 73.2 nanoseconds and a symbol duration may be 1041.7 nanoseconds. As described above, in some cases, a base station may be required to switch beams between a first RACH occasion and a second RACH occasion. As noted above, typically, the beam switch time (e.g., the amount of time required for the base station to switch beams) can be absorbed in the CP duration (e.g., for smaller SCS sizes). However, in higher bands with larger SCS (e.g., 960 kHz and/or above), the CP duration may not provide enough time to absorb the beam switch time of the base station. As a result, the beam switch time may extend into a symbol of a signal (e.g., of a RACH message), resulting in the base station not receiving some, or all, data carried by the signal. Therefore, the SSB to RACH association mapping may be insufficient in higher bands and/or with different waveform types (e.g., with SC waveforms), as described above. Furthermore, during the guard period that often buffers RACH occasions, as shown above, the base station typically continues to monitor and/or receive signals from UEs. As such, a base station cannot switch beams during the guard period as the base station may still be receiving signals from various UEs during the guard period.

Some techniques and apparatuses described herein enable downlink initial access signal (IAS) to RACH occasion association that addresses one or more (or all) of the problems associated with SSB to RACH occasion mappings in higher bands and/or with different waveform types described above. For example, a base station may configure a UE with a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates switching gaps between downlink IAS occasions (e.g., SSBs, another IAS, and/or a combination of signals associated with initial access) and between RACH occasions (e.g., to accommodate beam switching times and/or downlink/uplink switching times) and/or frequency domain guard bands between RACH occasions (e.g., to enable an SC waveform to use RACH occasions that are FDM). The switching gap can reflect a time gap during which the base station does not monitor and/or receive any signals to enable the base station to switch from one beam (having a first direction) to another beam (having a second direction) and/or to switch from an uplink beam to a downlink beam, or vice versa. In some aspects, the downlink IAS to RACH occasion association pattern may be mapped in the time domain only (e.g., may not be mapped in the frequency domain) to account for SC waveforms that may be used to communicate using a RACH occasion. In some aspects, the downlink IAS to RACH occasion association pattern may group or cluster downlink IAS for different beams together and may group or cluster RACH occasions for different beams together. In some aspects, the downlink IAS to RACH occasion association pattern may group or cluster a downlink IAS and RACH occasion(s) associated with the same beam together. As a result, the downlink IAS to RACH occasion association pattern may account for larger SCS and/or shorter CP durations in higher bands by including one or more switching gaps (e.g., beam switching gaps and/or downlink/uplink switching gaps) between downlink IASs and/or between RACH occasions. Additionally, or alternatively, the downlink IAS to RACH occasion association pattern may account for different waveform types, such as SC waveforms, that may be used in higher frequency bands by mapping the downlink IAS to RACH occasion association pattern in the time domain only and/or by including guard bands between FDM RACH occasions included in the downlink IAS to RACH occasion association pattern.

FIG. 7is a diagram illustrating an example700associated with downlink IAS to RACH occasion association, in accordance with the present disclosure. As shown inFIG. 7, a base station110and a UE120may communicate with one another in a wireless network, such as wireless network100.

As described above, the base station110may transmit one or more downlink IASs to enable the UE120to establish a connection with the base station110. “Downlink IAS” or “DL IAS” may refer to a signal, or combination of signals, that enables a UE (e.g., the UE120) or another device to establish a connection with a base station (e.g., the base station110). For example, a downlink IAS may include an SSB, a control resource set (CORESET) signal, a downlink control information (DCI) signal, an SIB signal, and/or any combination thereof, among other examples. For example, a downlink IAS may be a combination of an SSB signal and a CORESET signal (e.g., an SSB and a CORESET 0 signal, as defined, or otherwise fixed, by the 3GPP). In some aspects, a downlink IAS may be a combination of an SSB signal and a DCI signal (e.g., an SSB and a DCI 1_0 signal, as defined, or otherwise fixed, by the 3GPP). In some aspects, a downlink IAS may be a combination of an SSB signal, a CORESET 0 signal, a DCI 1_0 signal, and/or an SIB signal (e.g., an SIB 1 signal, as defined, or otherwise fixed, by the 3GPP). The combinations of signals described above are provided as examples and a downlink IAS may include any combination of signals transmitted by the base station110that may enable a UE or another device to establish a connection with the base station110.

As shown by reference number705, the base station110may determine a downlink IAS to RACH occasion association pattern to be associated with the base station110and the UE120(and/or a group of UEs that includes the UE120). In some aspects, the downlink IAS to RACH occasion association pattern may be used by the base station110(e.g., and one or more UEs, such as the UE120) for higher frequency bands (e.g., millimeter wave bands) and/or for operating frequencies having a high SCS (e.g., 960 kHz and/or above), among other examples.

In some aspects, the base station110may determine that the downlink IAS to RACH occasion association pattern may be a first pattern that includes a group of downlink IAS occasions (e.g., transmission opportunities for a downlink IAS signal) for different beams associated with the base station110and a group of RACH occasions associated with the group of downlink IAS occasions, where the group of downlink IAS occasions are grouped together in the time domain and the group of RACH occasions are grouped together in the time domain. The first pattern may include switching gaps (e.g., beam switching gaps) between each downlink IAS occasion and/or between each RACH occasion. The first pattern is depicted and described in more detail below in connection withFIG. 8and reference numbers805and810.

In some aspects, the base station110may determine that the downlink IAS to RACH occasion association pattern may be a second pattern that includes a downlink IAS associated with a beam grouped with a RACH occasion associated with the beam (e.g., and the downlink IAS) in the time domain. In some aspects, the second pattern may include the downlink IAS and the RACH occasion being multiplexed in the time domain and/or the frequency domain. In some aspects, the second pattern may include a downlink/uplink switching gap between the downlink IAS and the RACH occasion. “Downlink/uplink switching gap” may refer to an amount of time required for the base station110to switch from transmitting downlink communications to receiving uplink communications, or from receiving uplink communications to transmitting downlink communications. The second pattern is depicted and described in more detail below in connection withFIG. 8and reference numbers815and820.

In some aspects, the base station110may determine that the downlink IAS to RACH occasion association pattern includes guard bands between downlink IASs and/or between RACH occasions. As described above, a guard band may be one or more frequency resources (e.g., one or more resource elements (REs) that are not allocated for any signal (e.g., that are intentionally not used by the UE120and/or the base station110for communicating signals). The downlink IAS to RACH occasion association pattern may include a first RACH occasion frequency division multiplexed with a second RACH occasion and a guard band included between the first RACH occasion and the second RACH occasion in the frequency domain. In some aspects, the base station110may determine that guard bands are to be included in the downlink IAS to RACH occasion association pattern when frequency division multiplexing is used and when a waveform type used is an SC waveform (e.g., the SC-QAM waveform type). For example, the base station110may perform filtering and apply SC processing in each RACH occasion (e.g., where the frequency resources allocated for the RACH occasion may serve as a sub-band). For example, each RACH occasion may be sent using X MHz, where the base station110supports Y MHz for initial access procedures (e.g., where Y is larger than X). The guard band may enable the filtering to be performed for each RACH occasion without causing interference between the frequency division multiplexed RACH occasions where an SC waveform type is used.

In some aspects, the base station110may determine whether to use the first pattern or the second pattern for the downlink IAS to RACH occasion association pattern. For example, the base station110may determine whether to use the first pattern or the second pattern based at least in part on a length of a downlink to uplink switching time of the base station110, a length of a beam switching time of the base station110, a number of downlink IAS occasions associated with the downlink IAS to RACH occasion association pattern, and/or an amount of time associated with channel acquisition for the UE120. For example, switching gaps associated with the first pattern may be associated with beam switching, whereas switching gaps associated with the second pattern may be associated with downlink/uplink switching. Therefore, in some aspects, if the length of the downlink to uplink switching time of the base station110is less than the length of a beam switching time of the base station110, then the base station110may determine to use the second pattern, as the duration of the downlink/uplink switch gaps may be less than a duration of the beam switching gaps (e.g., of the first pattern). As a result, the base station110may reduce a required switching gap overhead associated with the downlink IAS to RACH occasion association pattern, thereby conserving resources and reducing a latency associated with a RACH procedure. Alternatively, if the length of the downlink to uplink switching time of the base station110is greater than the length of a beam switching time of the base station110, then the base station110may determine to use the first pattern, as the duration of the downlink/uplink switch gaps may be greater than the duration of the beam switching gaps.

As another example, if an amount of time associated with channel acquisition for the UE120(e.g., a time limit associated with channel acquisition of the UE120) is below a threshold, then the base station110may determine to use the first pattern as the downlink IAS to RACH occasion association pattern. For example, the second pattern may be associated with an increased UE channel acquisition time, as an amount of time between downlink IASs transmitted by the base station110may be increased as compared to the first pattern (e.g., as described in more detail below in connection withFIG. 8). Therefore, if the UE120is required to acquire the channel (e.g., with the base station) quickly (e.g., if a time limit associated with channel acquisition of the UE120is below a threshold), then the base station110may determine to use the first pattern to reduce the UE channel acquisition time.

In some aspects, the base station110may determine that an ordering of RACH occasions may be varied between association periods. “Association period” may refer to a period of time that a mapping between downlink IASs and RACH occasions is valid or applicable. The downlink IAS to RACH occasion association pattern may include one or more association periods. The base station110may determine that the downlink IAS to RACH occasion association pattern includes a first order of RACH occasions in the time domain for a first association period and a second order of RACH occasions in the time domain for a second association period. This may reduce a latency associated with channel acquisition for the UE120. For example, if the order of the RACH occasions remained the same for each association period, some RACH occasions may continually occur later in time than other RACH occasions. Therefore, if the UE120is to use a RACH occasion that occurs later in time, then an amount of time for the UE120to acquire the channel may be increased. However, if the order of the RACH occasions is varied for each association period, then the UE120may be enabled to acquire the channel in a shorter amount of time (e.g., during an associated period where the RACH occasion occurs earlier in time as compared to a different association period). As a result, a latency for different RACH occasions may be varied or balanced among different association periods. This may enable some UEs (e.g., that require RACH occasions that would have otherwise always occurred later in time) to decrease a latency associated with channel acquisition. The varied ordering of RACH occasions between association periods is depicted and described in more detail below in connection withFIG. 9.

In some aspects, the base station110may determine that the downlink IAS to RACH occasion association pattern includes an unbalanced or non-uniform distribution of a number of RACH occasions mapped to each downlink IAS. For example, the downlink IAS to RACH occasion association pattern may include a first downlink IAS associated with a first number of RACH occasions and a second downlink IAS associated with a second number of RACH occasions (e.g., that is different than the first number of RACH occasions). For example, the first downlink IAS may be associated with more RACH occasions than the second downlink IAS. For example, a beam associated with the first downlink IAS may be associated with a spatial direction towards an area with a higher concentration of UEs than an area associated with a spatial direction of a beam associated with the second downlink IAS. Therefore, the downlink IAS to RACH occasion association pattern may include more RACH occasions associated with the first downlink IAS to increase channel access opportunities for UEs in the area with the higher concentration of UEs. The downlink IAS to RACH occasion association pattern with unbalanced or non-uniform distribution of a number of RACH occasions mapped to each downlink IAS is depicted and described in more detail below in connection withFIG. 10.

As described above, the downlink IAS to RACH occasion association pattern may include switching gaps between downlink IASs and/or between RACH occasions to enable the base station110and/or the UE120to perform switching (e.g., beam switching and/or downlink/uplink switching) In some aspects, the switching gaps may be explicit switching gaps. For example, a downlink IAS to RACH occasion association pattern may include one or more time domain resources (e.g., that are unused or not allocated for a signal or RACH occasion) between a first RACH occasion and a second RACH occasion that occurs directly after the first RACH occasion. In some aspects, the switching gaps may include a switching gap included in a CP of a RACH message transmitted using a RACH occasion (e.g., a switching gap that occurs at the start of a RACH occasion, such as during the CP). In some aspects, the switching gaps may be extended guard period switching gaps and/or extended CP switching gaps. An extended guard period switching gap or extended CP switching gap may be associated with a RACH message (or RACH occasion) that includes a guard period or CP that is extended to absorb the switching time. Therefore, the base station110may perform switching during the extended guard period or CP. As discussed above, as typically understood, the guard period is a period where the base station may continue to monitor and/or receive signals from different UEs. However, here, where the switching gap may be included in the guard period, it is understood that the guard period may therefore include a time where the base station continues to monitor and/or receive signals from different UEs and also a time where the base station does not monitor and/or receive signals to enable the base station to switch between different beams and/or switch between an uplink beam and a downlink beam. Similarly, for an extended CP switching gap, the base station may not monitor and/or receive signals during part of the CP when it is switching beams and may monitor and/or receive during another part of the CP. In some aspects, the switching gaps may be sub-symbol switching gaps, such as when a DFT-s-OFDM waveform is used. A sub-symbol switching gap may be associated with a RACH message that includes a tail symbol (e.g., one or more low energy samples included in the symbol of the RACH message). The tail symbol may serve as an additional guard period, thereby enabling the base station110to initiate a switch during the original or configured guard period. The different types of switching gaps are depicted and described in more detail below in connection withFIG. 11.

As shown by reference number710, the base station110may transmit, and the UE120may receive, configuration information (e.g., random access configuration information) indicating the downlink IAS to RACH occasion association pattern. For example, the base station110may transmit, and the UE120may receive, an indication of the downlink IAS to RACH occasion association pattern indicating switching gaps between downlink IAS occasions and between RACH occasions, guard bands between RACH occasions, the first pattern, the second pattern, a varied ordering of RACH occasions between association periods, an unbalanced or non-uniform distribution of a number of RACH occasions mapped to each downlink IAS, and/or a type of switching gap, among other examples. In some aspects, the base station110may transmit the configuration information indicating the downlink IAS to RACH occasion association pattern in an SIB, such as SIB 1.

As shown by reference number715, the base station110may transmit, and the UE120may receive, one or more downlink IASs. For example, the base station110may transmit one or more SSBs. The base station110may be enabled to perform beam switching and/or downlink/uplink switching while transmitting the one or more downlink IASs based at least in part on the downlink IAS to RACH occasion association pattern. For example, the switching gaps included in the downlink IAS to RACH occasion association pattern may enable the base station110to perform beam switching and/or downlink/uplink switching while transmitting the one or more downlink IASs.

The UE120may monitor for and receive one or more downlink IASs transmitted by the base station110. The UE120may select a downlink IAS to be associated with a RACH procedure based at least in part on receiving the one or more downlink IASs transmitted by the base station110. For example, the UE120may measure a beam associated with the one or more downlink IASs to identify an acceptable beam (e.g., a beam having a measurement value that satisfies a threshold) for communications between the UE120and the base station110.

As shown by reference number720, the UE120may select a RACH occasion to transmit a RACH message based at least in part on (e.g., according to) the downlink IAS to RACH occasion association pattern. For example, the UE120may identify one or more RACH occasions associated with the downlink IAS received by the UE120as described above. The UE120may select a RACH occasion (e.g., randomly) from the one or more RACH occasions associated with the downlink IAS.

As shown by reference number725, the UE120may transmit, and the base station110may receive, a RACH message (e.g., a msgA and/or a msg1) using a RACH occasion according to the downlink IAS to RACH occasion association pattern. For example, the UE120may receive an indication of the downlink IAS to RACH occasion association pattern, receive a downlink IAS, select a RACH occasions according to the downlink IAS to RACH occasion association pattern, and transmit a RACH message using the selected RACH occasion. The base station110may identify a downlink IAS and/or a beam associated with the RACH message based at least in part on the downlink IAS to RACH occasion association pattern. As shown by reference number730, the base station110and the UE120may perform a RACH procedure (e.g., a two-step RACH procedure as described above in connection withFIG. 4or a four-step RACH procedure as described above in connection withFIG. 5) based at least in part on the UE120transmitting, and the base station110receiving, the RACH message using the RACH occasion.

As a result, the downlink IAS to RACH occasion association pattern may account for larger SCS and/or shorter CP durations in higher bands by including one or more switching gaps (e.g., beam switching gaps and/or downlink/uplink switching gaps) between downlink IASs and/or between RACH occasions. Additionally, or alternatively, the downlink IAS to RACH occasion association pattern may account for different waveform types, such as SC waveforms, that may be used in higher frequency bands by mapping the downlink IAS to RACH occasion association pattern in the time domain only and/or by including guard bands between FDM RACH occasions included in the downlink IAS to RACH occasion association pattern.

As indicated above,FIG. 7is provided as an example. Other examples may differ from what is described with respect toFIG. 7.

FIG. 8is a diagram illustrating an example800associated with downlink IAS to RACH occasion association, in accordance with the present disclosure.FIG. 8depicts different examples of downlink IAS to RACH occasion association patterns, as described above in connection withFIG. 7. For example, as shown by reference number805, the downlink IAS to RACH occasion association pattern may be the first pattern described above in connection withFIG. 7. As shown by reference number815, the downlink IAS to RACH occasion association pattern may be the second pattern described above in connection withFIG. 7. In some aspects, a base station110may determine whether to use the first pattern or the second pattern for the downlink IAS to RACH occasion association pattern, as described herein.

As shown by reference number805, the first pattern may include downlink (DL) IAS signals grouped together in the time domain and RACH occasions (ROs) grouped together in the time domain. For example, in accordance with the first pattern, the base station110may transmit a first downlink IAS (e.g., DL IAS1) using a first beam, may transmit a second downlink IAS (e.g., DL IAS2) using a second beam, and may transmit a third downlink IAS (e.g., DL IAS3) using a third beam. The downlink IASs may be mapped to, or associated with, RACH occasions, as described above. In some aspects, the downlink IASs may be mapped to, or associated with, RACH occasions only in the time domain (e.g., not in the frequency domain). In other words, the RACH occasions may be time division multiplexed with one another, but not frequency division multiplexed. In some aspects, the downlink IASs may be mapped to, or associated with, RACH occasions in the time domain and/or the frequency domain. In other words, the RACH occasions may be time division multiplexed and/or frequency division multiplexed with one another.

As shown by reference number810, the downlink IAS to RACH occasion association pattern may include a beam switching gap overhead. For example, the downlink IAS to RACH occasion association pattern may include one or more opportunities for the base station110(and/or the UE120) to perform beam switching. For example, as downlink IASs may be grouped together, the base station110may be required to switch from a first beam to a second beam when switching from the first downlink IAS to the second downlink IAS. The opportunities for the base station110(and/or the UE120) to perform beam switching are depicted and described in more detail below in connection withFIG. 11.

As shown by reference number815, the second pattern may include downlink IASs and associated RACH occasions grouped together in the time domain. For example, the second pattern may include a first downlink IAS (e.g., DL IAS1) followed by one or more associated RACH occasions for the first downlink IAS (e.g., RO for DL IAS1) in the time domain. As a result, a beam switching gap overhead may be reduced as the number of beam switches that are required to be performed in the second pattern is reduced (e.g., as compared to the first pattern). As shown by reference number820, the second pattern may include a downlink/uplink (DL/UL) switching gap overhead. For example, the second pattern may include one or more opportunities for the base station110(and/or the UE120) to switch between communicating downlink signals (e.g., downlink IASs) and uplink signals (e.g., RACH messages using a RACH occasion). The opportunities for the base station110(and/or the UE120) to perform downlink/uplink switching are depicted and described in more detail below in connection withFIG. 11.

In some aspects, the second pattern may be used where an amount of time associated with downlink/uplink switching for a base station110is less than an amount of time for beam switching for the base station110. Conversely, the first pattern may be used where the amount of time for beam switching for the base station110is less than the amount of time associated with downlink/uplink switching for the base station110. Additionally, or alternatively, the first pattern may be used where a time limit for channel acquisition for a UE120is below a threshold. For example, the second pattern may be associated with an increased channel acquisition time as compared to the first pattern (e.g., as the downlink IASs may be transmitted later in the time domain as compared to the first pattern). For example, as shown inFIG. 8, the third downlink IAS may be transmitted earlier in the time domain in the first pattern as compared to a transmission time of the third downlink IAS in the second pattern. Therefore, if a time limit for channel acquisition for a UE120is below a threshold, then the base station110may determine that the first pattern should be used.

As indicated above,FIG. 8is provided as an example. Other examples may differ from what is described with respect toFIG. 8.

FIG. 9is a diagram illustrating an example900associated with downlink IAS to RACH occasion association, in accordance with the present disclosure.FIG. 9depicts an example of varied ordering of RACH occasions between association periods.

As described above, the downlink IAS to RACH occasion association pattern may include one or more association periods. For example, a base station110may transmit K downlink IASs that are mapped to, or associated with, K RACH occasions.FIG. 9depicts a one-to-one mapping of downlink IAS to RACH occasions. However, a one-to-many (e.g., where one downlink IAS is mapped to multiple RACH occasions) mapping of downlink IAS to RACH occasion is also possible, following a similar approach as described herein (e.g., a RACH occasion depicted inFIG. 9, such as RO 1, may include multiple RACH occasions).

As shown by reference number905, in a first association period, the RACH occasions may be ordered, in the time domain, from RACH occasions for the first downlink IAS to RACH occasions for the Kth downlink IAS. As shown by reference number910, in a second association period, the RACH occasions may be ordered, in the time domain, from RACH occasions for the Kth downlink IAS to RACH occasions for the first downlink IAS (e.g., a different and/or reversed order as compared to the order associated with the first association period). As shown by reference number915, in a third association period, the RACH occasions may be ordered, in the time domain, from RACH occasions for the first downlink IAS to RACH occasions for the Kth downlink IAS (e.g., the same order as the order associated with the first association period).

For example, in some aspects, the downlink IAS to RACH occasion association pattern may include a RACH ordering pattern (e.g., where an order of RACH occasions changes, or reverses, in accordance with a pattern from one association period to a next association period). In some aspects, an ordering of RACH occasions may not be from 1 to K, or from K to 1. For example, the order of RACH occasions may be random and/or may be different than following numerically from 1 to K, or from K to 1. By varying the order of RACH occasions from one association period to a next association period, a latency for channel acquisition for different downlink IAS (e.g., and for associated RACH occasions) can be balanced. For example, if a UE120uses RACH occasion K, then the UE120may have to wait until the end of the downlink IAS to RACH occasion association pattern (e.g., in the time domain) during the first association period to transmit a RACH message to initiate a RACH procedure and acquire the channel. However, during the second association period, the UE120may be enabled to transmit a RACH message to initiate a RACH procedure and acquire the channel earlier in the time domain due to the varied ordering of RACH occasions. As a result, a latency for channel acquisition between different downlink IASs and/or different RACH occasions can be balanced over time.

As indicated above,FIG. 9is provided as an example. Other examples may differ from what is described with respect toFIG. 9.

FIG. 10is a diagram illustrating an example1000associated with downlink IAS to RACH occasion association, in accordance with the present disclosure.FIG. 10depicts examples of unbalanced or non-uniform distribution of a number of RACH occasions mapped to each downlink IAS.

As described above, in some situations it may be desirable to have a downlink IAS mapped to, or associated with, more RACH occasions than another downlink IAS. For example, a downlink IAS may be associated with a beam (e.g., and therefore a spatial direction). In some aspects, the beam and/or the spatial direction may be associated with conditions that increase a difficulty to acquire the channel using the beam (e.g., and an associated RACH occasion). For example, a beam may be associated with a blockage (e.g., due to a building or other structure) or another condition may increase the difficulty to transmit messages using the beam. Therefore, it may be desirable to increase a number of RACH occasions associated with that beam (e.g., and the downlink IAS) to increase a number of opportunities for a UE120to transmit a RACH message and/or acquire the channel. As another example, a first beam may be associated with a spatial direction towards an area with a high concentration of UEs (e.g., as compared to another spatial direction), such as a public transportation terminal, an office building, a venue, and/or an arena, among other examples. In some aspects, a second beam may be associated with a spatial direction towards an area with a low concentration of UEs. Therefore, it may be desirable to provide a larger number of RACH occasions for the first beam (e.g., and the first downlink IAS) than a number of RACH occasions for the second beam (e.g., and the second downlink IAS), to increase a number of opportunities for UEs in the area of high concentration of UEs to acquire the channel.

For example, as shown by reference numbers1010and1020, a first downlink IAS (e.g., DL IAS1) may be associated with a first number (e.g., one) of RACH occasions (e.g., RO 1) and a second downlink IAS (e.g., DL IAS2) may be associated with a second number (e.g., two) of RACH occasions (e.g., RO 2). Reference number1010may depict an unbalanced or non-uniform distribution of a number of RACH occasions mapped to each downlink IAS for a downlink IAS to RACH occasion association pattern that uses the first pattern as described above. Reference number1020may depict an unbalanced or non-uniform distribution of a number of RACH occasions mapped to each downlink IAS for a downlink IAS to RACH occasion association pattern that uses the second pattern as described above.

As indicated above,FIG. 10is provided as an example. Other examples may differ from what is described with respect toFIG. 10.

FIG. 11is a diagram illustrating an example1100associated with downlink IAS to RACH occasion association, in accordance with the present disclosure.FIG. 11depicts examples of different switching gaps or switching opportunities for a downlink IAS to RACH occasion association pattern. As described above, a switching gap or a switching opportunity may be used by a base station110and/or a UE120for performing beam switching (e.g., when using the first pattern as described above) and/or for performing downlink/uplink switching (e.g., when using the second pattern as described above).FIG. 11depicts example switching gaps or switching opportunities between RACH occasions (e.g., between an RO 1 and an RO 2). However, similar switching gaps or switching opportunities may be included between downlink IASs, as described above.

As shown by reference number1110, a switching gap or a switching opportunity may be an explicit switching gap. For example, as shown by reference number1120, a switching gap or switching opportunity may occur during a time gap (e.g., one or more time domain resources that are not allocated for a signal) between the first RACH occasion and the second RACH occasion.

As shown by reference number1130, a switching gap or a switching opportunity may be a CP based switching gap. For example, in some aspects, a duration of a CP (e.g., a time at the start of the RACH occasion) may be sufficient for a base station110and/or a UE120to perform switching (e.g., beam switching and/or downlink/uplink switching). As shown by reference number1140, a switching gap or switching opportunity may occur during a CP (e.g., or a guard interval depending on a format of the RACH message or the downlink IAS) of the second RACH occasion (e.g., a RACH message transmitted using the second RACH occasion).

As shown by reference number1150, a switching gap or a switching opportunity may be a sub-symbol based switching gap. For example, as described above, a tail symbol may be inserted into a RACH message generated by a UE120. The tail symbol may be associated with one or more low energy samples inserted into the signal by the UE120. The tail symbol may serve as an additional guard period (GP) for the RACH message. As a result, a base station110and/or a UE120may be enabled to perform switching (e.g., beam switching and/or downlink/uplink switching) during the guard period of the RACH message. For example, as shown by reference number1160, a switching gap or switching opportunity may occur during a GP of the first RACH occasion (e.g., a RACH message transmitted using the first RACH occasion). In some aspects, the switching gap or switching opportunity may extend into a CP of the second RACH occasion (e.g., a RACH message transmitted using the second RACH occasion). In some aspects, a sub-symbol based switching gap may be used if a waveform type used by the base station110and/or the UE120is the DFT-s-OFDM waveform type.

As shown by reference number1170, a switching gap or a switching opportunity may be an extended GP switching gap. For example, in some aspects, a UE120may (e.g., and/or a base station110may configure the UE120to) extend a duration of a GP of a RACH message. By extending the duration of the GP of the RACH message, the base station110and/or the UE120may be enabled to perform switching (e.g., beam switching and/or downlink/uplink switching) during the GP of the RACH message. For example, as shown by reference number1180, a switching gap or switching opportunity may occur during an extended GP of the first RACH occasion (e.g., a RACH message transmitted using the first RACH occasion).

As indicated above,FIG. 11is provided as an example. Other examples may differ from what is described with respect toFIG. 11.

FIG. 12is a diagram illustrating an example process1200performed, for example, by a UE, in accordance with the present disclosure. Example process1200is an example where the UE (e.g., UE120) performs operations associated with downlink IAS to RACH occasion association.

As shown inFIG. 12, in some aspects, process1200may include receiving, from a base station, configuration information indicating a downlink IAS RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions (block1210). For example, the UE (e.g., using reception component1402, depicted inFIG. 14) may receive, from a base station, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions, as described above (e.g., with reference toFIGS. 7, 8, 9, 10, and/or11).

As further shown inFIG. 12, in some aspects, process1200may include transmitting, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern (block1220). For example, the UE (e.g., using transmission component1404, depicted inFIG. 14) may transmit, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern, as described above (e.g., with reference toFIGS. 7, 8, 9, 10, and/or11).

In a first aspect, the downlink IAS includes at an SSB signal, a CORESET signal, a DCI signal, an SIB signal, or any combination thereof.

In a second aspect, alone or in combination with the first aspect, receiving the configuration information includes receiving an indication that the downlink IAS to RACH occasion association pattern includes a group of downlink IAS occasions for different beams associated with the base station and a group of RACH occasions associated with the group of downlink IAS occasions, wherein the group of downlink IAS occasions are grouped together in a time domain and the group of RACH occasions are grouped together in the time domain.

In a third aspect, alone or in combination with one or more of the first and second aspects, the group of downlink IAS occasions includes switching gaps between downlink IAS occasions included in the group of downlink IAS occasions, and the group of RACH occasions includes switching gaps between RACH occasions included in the group of RACH occasions.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, receiving the configuration information includes receiving an indication that the downlink IAS to RACH occasion association pattern includes a downlink IAS associated with a beam grouped with a RACH occasion associated with the beam in a time domain.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, receiving the configuration information includes receiving an indication that the downlink IAS and the RACH occasion are multiplexed in at least one of the time domain or the frequency domain.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, receiving the configuration information includes receiving an indication of a downlink/uplink switching gap between the downlink IAS and the RACH occasion.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the downlink IAS to RACH occasion association pattern is based at least in part on: a length of a downlink to uplink switching time of the base station, a length of a beam switching time of the base station, a number of downlink IAS occasions associated with the downlink IAS to RACH occasion association pattern, an amount of time associated with channel acquisition for the UE, or any combination thereof.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, receiving the configuration information includes receiving an indication that the downlink IAS to RACH occasion association pattern includes a first order of RACH occasions in a time domain for a first association period and a second order of RACH occasions in the time domain for a second association period.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, receiving the configuration information includes receiving an indication that the downlink IAS to RACH occasion association pattern includes a first downlink IAS associated with a first number of RACH occasions and a second downlink IAS associated with a second number of RACH occasions.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, receiving the configuration information includes receiving an indication that the downlink IAS to RACH occasion association pattern includes a first RACH occasion frequency division multiplexed with a second RACH occasion and a guard band included between the first RACH occasion and the second RACH occasion in the frequency domain.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, receiving the configuration information includes receiving an indication that the downlink IAS to RACH occasion association pattern is associated with a single carrier waveform type.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, receiving the configuration information includes receiving an indication that the switching gaps include at least one of downlink to uplink switching gaps or beam switching gaps, where a switching gap includes: an explicit switching gap, a switching gap included in a cyclic prefix, a sub-symbol switching gap, an extended guard period switching gap, or any combination thereof.

AlthoughFIG. 12shows example blocks of process1200, in some aspects, process1200may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIG. 12. Additionally, or alternatively, two or more of the blocks of process1200may be performed in parallel.

FIG. 13is a diagram illustrating an example process1300performed, for example, by a base station, in accordance with the present disclosure. Example process1300is an example where the base station (e.g., base station110) performs operations associated with downlink IAS to RACH occasion association.

As shown inFIG. 13, in some aspects, process1300may include transmitting, to one or more UEs, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions (block1310). For example, the base station (e.g., using transmission component1504, depicted inFIG. 15) may transmit, to one or more UEs, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions, as described above (e.g., with reference toFIGS. 7, 8, 9, 10, and/or11).

As further shown inFIG. 13, in some aspects, process1300may include receiving, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern (block1320). For example, the base station (e.g., using reception component1502, depicted inFIG. 15) may receive, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern, as described above (e.g., with reference toFIGS. 7, 8, 9, 10, and/or11).

In a first aspect, the downlink IAS includes at an SSB signal, a CORESET signal, a DCI signal, an SIB signal, or any combination thereof.

In a second aspect, alone or in combination with the first aspect, transmitting the configuration information includes transmitting an indication that the downlink IAS to RACH occasion association pattern includes a group of downlink IAS occasions for different beams associated with the base station and a group of RACH occasions associated with the group of downlink IAS occasions, where the group of downlink IAS occasions are grouped together in a time domain and the group of RACH occasions are grouped together in the time domain.

In a third aspect, alone or in combination with one or more of the first and second aspects, the group of downlink IAS occasions includes switching gaps between downlink IAS occasions included in the group of downlink IAS occasions, and the group of RACH occasions includes switching gaps between RACH occasions included in the group of RACH occasions.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, transmitting the configuration information includes transmitting an indication that the downlink IAS to RACH occasion association pattern includes a downlink IAS associated with a beam grouped with a RACH occasion associated with the beam in a time domain.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, transmitting the configuration information includes transmitting an indication that the downlink IAS and the RACH occasion are multiplexed in at least one of the time domain or a frequency domain.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, transmitting the configuration information includes transmitting an indication of a downlink/uplink switching gap between the downlink IAS and the RACH occasion.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, process1300includes determining the downlink IAS to RACH occasion association pattern based at least in part on: a length of a downlink to uplink switching time of the base station, a length of a beam switching time of the base station, a number of downlink IAS occasions associated with the downlink IAS to RACH occasion association pattern, an amount of time associated with channel acquisition for the UE, or any combination thereof.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, process1300includes determining whether the downlink IAS to RACH occasion association pattern includes downlink IASs grouped together and RACH occasions group together, or downlink IASs and RACH occasions associated with a same beam grouped together.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, transmitting the configuration information includes transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first order of RACH occasions in a time domain for a first association period and a second order of RACH occasions in the time domain for a second association period.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, transmitting the configuration information includes transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first downlink IAS associated with a first number of RACH occasions and a second downlink IAS associated with a second number of RACH occasions.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, transmitting the configuration information includes transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first RACH occasion frequency division multiplexed with a second RACH occasion and a guard band included between the first RACH occasion and the second RACH occasion in a frequency domain.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, receiving the RACH message includes filtering a frequency domain resource allocation associated with the RACH occasion used to transmit the RACH message, and applying single carrier processing for the frequency domain resource allocation associated with the RACH occasion used to transmit the RACH message.

In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, transmitting the configuration information includes transmitting an indication that the downlink IAS to RACH occasion association pattern is associated with a single carrier waveform type.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, transmitting the configuration information includes transmitting an indication that the switching gaps include at least one of downlink to uplink switching gaps or beam switching gaps, wherein a switching gap includes: an explicit switching gap, a switching gap included in a cyclic prefix, a sub-symbol switching gap, an extended guard period switching gap, or any combination thereof.

FIG. 14is a block diagram of an example apparatus1400for wireless communication. The apparatus1400may be a UE, or a UE may include the apparatus1400. In some aspects, the apparatus1400includes a reception component1402and a transmission component1404, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus1400may communicate with another apparatus1406(such as a UE, a base station, or another wireless communication device) using the reception component1402and the transmission component1404. As further shown, the apparatus1400may include a RACH occasion selection component1408, among other examples.

In some aspects, the apparatus1400may be configured to perform one or more operations described herein in connection withFIGS. 7-11. Additionally, or alternatively, the apparatus1400may be configured to perform one or more processes described herein, such as process1200ofFIG. 12, or a combination thereof. In some aspects, the apparatus1400and/or one or more components shown inFIG. 14may include one or more components of the UE described above in connection withFIG. 2. Additionally, or alternatively, one or more components shown inFIG. 14may be implemented within one or more components described above in connection withFIG. 2. Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of the component.

The reception component1402may receive, from a base station, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions. The transmission component1404may transmit, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern. The RACH occasion selection component1408may select the RACH occasion based at least in part on the downlink IAS to RACH occasion association pattern.

The number and arrangement of components shown inFIG. 14are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown inFIG. 14. Furthermore, two or more components shown inFIG. 14may be implemented within a single component, or a single component shown inFIG. 14may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown inFIG. 14may perform one or more functions described as being performed by another set of components shown inFIG. 14.

FIG. 15is a block diagram of an example apparatus1500for wireless communication. The apparatus1500may be a base station, or a base station may include the apparatus1500. In some aspects, the apparatus1500includes a reception component1502and a transmission component1504, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus1500may communicate with another apparatus1506(such as a UE, a base station, or another wireless communication device) using the reception component1502and the transmission component1504. As further shown, the apparatus1500may include a determination component1508, among other examples.

The transmission component1504may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus1506. In some aspects, one or more other components of the apparatus1506may generate communications and may provide the generated communications to the transmission component1504for transmission to the apparatus1506. In some aspects, the transmission component1504may perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples), and may transmit the processed signals to the apparatus1506. In some aspects, the transmission component1504may include one or more antennas, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the base station described above in connection withFIG. 2. In some aspects, the transmission component1504may be co-located with the reception component1502in a transceiver.

The transmission component1504may transmit, to one or more UEs, configuration information indicating a downlink IAS to RACH occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions. The reception component1502may receive, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

The determination component1508may determine the downlink IAS to RACH occasion association pattern based at least in part on: a length of a downlink to uplink switching time of the base station, a length of a beam switching time of the base station, a number of downlink IAS occasions associated with the downlink IAS to RACH occasion association pattern, an amount of time associated with channel acquisition for the UE, or any combination thereof.

The determination component1508may determine whether the downlink IAS to RACH occasion association pattern includes downlink IASs grouped together and RACH occasions group together, or downlink IASs and RACH occasions associated with a same beam grouped together.

The number and arrangement of components shown inFIG. 15are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown inFIG. 15. Furthermore, two or more components shown inFIG. 15may be implemented within a single component, or a single component shown inFIG. 15may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown inFIG. 15may perform one or more functions described as being performed by another set of components shown inFIG. 15.

Aspect 1: A method of wireless communication performed by a user equipment (UE), comprising: receiving, from a base station, configuration information indicating a downlink initial access signal (IAS) to random access channel (RACH) occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and transmitting, to the base station, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

Aspect 2: The method of Aspect 1, wherein the downlink IAS includes: a synchronization signal block (SSB) signal, a control resource set (CORESET) signal, a downlink control information (DCI) signal, a system information block (SIB) signal, or any combination thereof.

Aspect 3: The method of any of Aspects 1-2, wherein receiving the configuration information comprises: receiving an indication that the downlink IAS to RACH occasion association pattern includes a group of downlink IAS occasions for different beams associated with the base station and a group of RACH occasions associated with the group of downlink IAS occasions, wherein the group of downlink IAS occasions are grouped together in a time domain and the group of RACH occasions are grouped together in the time domain.

Aspect 4: The method of Aspect 3, wherein the group of downlink IAS occasions includes switching gaps between downlink IAS occasions included in the group of downlink IAS occasions, and wherein the group of RACH occasions includes switching gaps between RACH occasions included in the group of RACH occasions.

Aspect 5: The method of any of Aspects 1-2, wherein receiving the configuration information comprises: receiving an indication that the downlink IAS to RACH occasion association pattern includes a downlink IAS associated with a beam grouped with a RACH occasion associated with the beam in a time domain.

Aspect 6: The method of Aspect 5, wherein receiving the configuration information comprises: receiving an indication that the downlink IAS and the RACH occasion are multiplexed in at least one of the time domain or a frequency domain.

Aspect 7: The method of any of Aspects 5-6, wherein receiving the configuration information comprises: receiving an indication of a downlink/uplink switching gap between the downlink IAS and the RACH occasion.

Aspect 8: The method of any of Aspects 1-7, wherein the downlink IAS to RACH occasion association pattern is based at least in part on: a length of a downlink to uplink switching time of the base station, a length of a beam switching time of the base station, a number of downlink IAS occasions associated with the downlink IAS to RACH occasion association pattern, an amount of time associated with channel acquisition for the UE, or any combination thereof.

Aspect 9: The method of any of Aspects 1-8, wherein receiving the configuration information comprises: receiving an indication that the downlink IAS to RACH occasion association pattern includes a first order of RACH occasions in a time domain for a first association period and a second order of RACH occasions in the time domain for a second association period.

Aspect 10: The method of any of Aspects 1-9, wherein receiving the configuration information comprises: receiving an indication that the downlink IAS to RACH occasion association pattern includes a first downlink IAS associated with a first number of RACH occasions and a second downlink IAS associated with a second number of RACH occasions.

Aspect 11: The method of any of Aspects 1-10, wherein receiving the configuration information comprises: receiving an indication that the downlink IAS to RACH occasion association pattern includes a first RACH occasion frequency division multiplexed with a second RACH occasion and a guard band included between the first RACH occasion and the second RACH occasion in a frequency domain.

Aspect 12: The method of Aspect 11, wherein receiving the configuration information comprises: receiving an indication that the downlink IAS to RACH occasion association pattern is associated with a single carrier waveform type.

Aspect 13: The method of any of Aspects 1-12, wherein receiving the configuration information comprises: receiving an indication that the switching gaps include at least one of downlink to uplink switching gaps or beam switching gaps, wherein a switching gap includes: an explicit switching gap, a switching gap included in a cyclic prefix, a sub-symbol switching gap, an extended guard period switching gap, or any combination thereof.

Aspect 14: A method of wireless communication performed by a base station, comprising: transmitting, to one or more user equipments (UEs), configuration information indicating a downlink initial access signal (IAS) to random access channel (RACH) occasion association pattern, wherein the downlink IAS to RACH occasion association pattern indicates at least one of switching gaps between downlink IAS occasions and between RACH occasions or guard bands between RACH occasions; and receiving, from a UE of the one or more UEs, a RACH message using a RACH occasion according to the downlink IAS to RACH occasion association pattern.

Aspect 15: The method of Aspect 14, wherein the downlink IAS includes: a synchronization signal block (SSB) signal, a control resource set (CORESET) signal, a downlink control information (DCI) signal, a system information block (SIB) signal, or any combination thereof.

Aspect 16: The method of any of Aspects 14-15, wherein transmitting the configuration information comprises: transmitting an indication that the downlink IAS to RACH occasion association pattern includes a group of downlink IAS occasions for different beams associated with the base station and a group of RACH occasions associated with the group of downlink IAS occasions, wherein the group of downlink IAS occasions are grouped together in a time domain and the group of RACH occasions are grouped together in the time domain.

Aspect 17: The method of Aspect 16, wherein the group of downlink IAS occasions includes switching gaps between downlink IAS occasions included in the group of downlink IAS occasions, and wherein the group of RACH occasions includes switching gaps between RACH occasions included in the group of RACH occasions.

Aspect 18: The method of any of Aspects 14-15, wherein transmitting the configuration information comprises: transmitting an indication that the downlink IAS to RACH occasion association pattern includes a downlink IAS associated with a beam grouped with a RACH occasion associated with the beam in a time domain.

Aspect 19: The method of Aspect 18, wherein transmitting the configuration information comprises: transmitting an indication that the downlink IAS and the RACH occasion are multiplexed in at least one of the time domain or a frequency domain.

Aspect 20: The method of any of Aspects 18-19, wherein transmitting the configuration information comprises: transmitting an indication of a downlink/uplink switching gap between the downlink IAS and the RACH occasion.

Aspect 21: The method of any of Aspects 14-20, further comprising: determining the downlink IAS to RACH occasion association pattern based at least in part on: a length of a downlink to uplink switching time of the base station, a length of a beam switching time of the base station, a number of downlink IAS occasions associated with the downlink IAS to RACH occasion association pattern, an amount of time associated with channel acquisition for the UE, or any combination thereof.

Aspect 22: The method of any of Aspects 14-21, further comprising: determining whether the downlink IAS to RACH occasion association pattern includes: downlink IASs grouped together and RACH occasions group together, or downlink IASs and RACH occasions associated with a same beam grouped together.

Aspect 23: The method of any of Aspects 14-22, wherein transmitting the configuration information comprises: transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first order of RACH occasions in a time domain for a first association period and a second order of RACH occasions in the time domain for a second association period.

Aspect 24: The method of any of Aspects 14-23, wherein transmitting the configuration information comprises: transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first downlink IAS associated with a first number of RACH occasions and a second downlink IAS associated with a second number of RACH occasions.

Aspect 25: The method of any of Aspects 14-24, wherein transmitting the configuration information comprises: transmitting an indication that the downlink IAS to RACH occasion association pattern includes a first RACH occasion frequency division multiplexed with a second RACH occasion and a guard band included between the first RACH occasion and the second RACH occasion in a frequency domain.

Aspect 26: The method of Aspect 25, wherein receiving the RACH message comprises: filtering a frequency domain resource allocation associated with the RACH occasion used to transmit the RACH message; and applying single carrier processing for the frequency domain resource allocation associated with the RACH occasion used to transmit the RACH message.

Aspect 27: The method of any of Aspects 25-26, wherein transmitting the configuration information comprises: transmitting an indication that the downlink IAS to RACH occasion association pattern is associated with a single carrier waveform type.

Aspect 28: The method of any of Aspects 14-27, wherein transmitting the configuration information comprises: transmitting an indication that the switching gaps include at least one of downlink to uplink switching gaps or beam switching gaps, wherein a switching gap includes: an explicit switching gap, a switching gap included in a cyclic prefix, a sub-symbol switching gap, an extended guard period switching gap, or any combination thereof.