Patent Description:
Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for synchronization signal block transmission using spatial division multiplexing.

Document <CIT>) proposes a method for detecting swept downlink beams comprising synchronization signal block (SSBs). Document <CIT>) deals with random access in <NUM> and proposes to associate SSBs with specific RACH resources. Document <CIT>) proposes a method for configuring the receiver of a UE by using an adaptation request (AR) via DCI in a PDCCH. Document <NPL>, touches upon the channel structure for a two-step RACH.

Controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform one or more techniques associated with synchronization signal block transmission using spatial division multiplexing, as described in more detail elsewhere herein. For example, controller/processor <NUM> of base station <NUM>, controller/processor <NUM> of UE <NUM>, and/or any other component(s) of <FIG> may perform or direct operations of, for example, process <NUM> of <FIG>, process <NUM> of <FIG>, and/or other processes as described herein. Memories <NUM> and <NUM> may store data and program codes for base station <NUM> and UE <NUM>, respectively. In some aspects, memory <NUM> and/or memory <NUM> may comprise a non-transitory computer-readable medium storing one or more instructions for wireless communication. For example, the one or more instructions, when executed by one or more processors of the base station <NUM> and/or the UE <NUM>, may perform or direct operations of, for example, process <NUM> of <FIG>, process <NUM> of <FIG>, and/or other processes as described herein.

In some aspects, UE <NUM> may include means for receiving, during a connected mode or an idle mode and from a base station, signaling identifying spatial resources of a set of synchronization signal block communications, wherein the set of synchronization signal block communications includes two or more synchronization signal block communications, means for receiving at least one of the set of synchronization signal block communications using spatial multiplexing corresponding to the spatial resources, wherein the set of synchronization signal block communications are each received concurrently using different spatial resources associated with beam sweeping transmission, means for determining, based at least in part on receiving the at least one of the set of synchronization signal block communications, a set of channel measurements, and/or the like. In some aspects, such means may include one or more components of UE <NUM> described in connection with <FIG>, such as controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, and/or the like.

In some aspects, base station <NUM> may include means for identifying, during a connected mode or an idle mode of a user equipment, a set of synchronization signal block communications, wherein the set of synchronization signal block communications includes two or more synchronization signal block communications, means for transmitting the set of synchronization signal block communications using spatial multiplexing, wherein the set of synchronization signal block communications are each transmitted concurrently using different spatial resources associated with beam sweeping transmission, and/or the like. In some aspects, such means may include one or more components of base station <NUM> described in connection with <FIG>, such as antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, and/or the like.

In some communications systems, a BS may transmit a synchronization signal block (SSB) communication to enable a UE to perform one or more measurements associated with configuring communication. For example, a UE may receive an SSB communication and perform a reference signal received power (RSRP) measurement to enable configuration of communication parameters for subsequent communications. The BS may use time division multiplexing to transmit a plurality of SSB communications, which may increase a likelihood of the UE successfully receiving at least one of the plurality of SSB communications. However, SSB communications may be associated with an excessive amount of overhead.

Some aspects described herein enable spatial multiplexing of SSB transmissions for beam sweeping. For example, a BS may transmit a plurality of SSBs with different spatial characteristics when beam sweeping. In this case, based at least in part on using spatial multiplexing, the BS and/or the UE may reduce overhead, achieve UE power savings, and/or the like. In this case, the UE may perform RSRP measurements on the spatially multiplexed SSB communications, thereby enabling configuration of communication parameters for subsequent communication.

<FIG> is a diagram illustrating an example <NUM> of SSB transmission using spatial division multiplexing, in accordance with various aspects of the present disclosure. As shown in <FIG>, example <NUM> includes a BS <NUM> and a UE <NUM>.

As further shown in <FIG>, and by reference number <NUM>, BS <NUM> may configure SSB communications. For example, BS <NUM> may configure spatial division multiplexing (which may be termed spatial multiplexing) for a set of SSB communications (e.g., two or more SSB communications). In this case, to perform beam sweeping across a set of beams {<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>}, BS <NUM> may configure multiple subsets of spatially multiplexed SSB communications. For example, BS <NUM> may configure beam sweeping a first set of SSB communications using a first set of beams {<NUM>, <NUM>}, a second set of SSB communications using a second set of beams {<NUM>, <NUM>}, and a third set of SSB communications using a third set of beams {<NUM>, <NUM>}. In this case, BS <NUM> may determine to beam sweep across the three sets [{<NUM>, <NUM>}, {<NUM>, <NUM>}, {<NUM>, <NUM>}], thereby enabling decreased measurement overhead for UE <NUM>. Although some aspects are described herein in terms of two SSB communications being spatially multiplexed onto two beams, other quantities of SSB communications on other quantities of beams are contemplated.

In some aspects, BS <NUM> may select the multiple sets of beams for the multiple sets of spatially multiplexed SSB communications to achieve a threshold spatial separation. For example, BS <NUM> may determine to transmit using beams <NUM> and <NUM> concurrently based at least in part on an angular separation between beams <NUM> and <NUM> being larger than, for example, an angular separation between beams <NUM> and <NUM>.

In some aspects, BS <NUM> may configure demodulation reference sequences for the SSB communications. For example, BS <NUM> may assign orthogonal demodulation reference signal (DMRS) sequences to SSB communications that are to be transmitted concurrently (e.g., a first DMRS to a first SSB communication on beam <NUM>, and a second DMRS, which is orthogonal to the first DMRS, to a second SSB communication on beam <NUM>). In this way, BS <NUM> may enable UE <NUM> to differentiate between SSB communications on different beams and measure separate channel quality parameters for each SSB communication. In some aspects, BS <NUM> may configure orthogonality for the first DMRS and the second DMRS with respect to differing times, differing frequencies, differing codes (e.g., differing overlay Walsh codes), and/or the like.

In some aspects, BS <NUM> may configure differing physical broadcast channel (PBCH) payloads for the SSB communications. For example, BS <NUM> may cause a first SSB communication to have a first PBCH payload and a second SSB communication to have a second PBCH payload. In this case, the first PBCH payload may differ from the second PBCH payload with respect to corresponding SSB indices of the respective PBCH payloads. Alternatively, the first PBCH payload and the second PBCH payload may be portions of a common payload.

As further shown in <FIG>, and by reference number <NUM>, BS <NUM> may transmit information identifying a configuration of the SSB communications to UE <NUM>. For example, BS <NUM> may provide information indicating that UE <NUM> is to concurrently receive SSB communications on a first set of beams {<NUM>, <NUM>} at a first time, a second set of beams {<NUM>, <NUM>} at a second time, a third set of beams {<NUM>, <NUM>} at a third time, and/or the like. In some aspects, BS <NUM> may provide the information identifying the configuration of the SSB communications using a PBCH. For example, BS <NUM> may provide a compressed indication in the PBCH to convey information regarding spatial multiplexing of the SSB communications. Additionally, or alternatively, BS <NUM> may provide a bitmap using connected mode radio resource control (RRC) signaling to convey information regarding spatial multiplexing of the SSB communications. In this case, the bitmap may have bits to indicate whether an SSB communication is to be transmitted on a particular beam. In some aspects, BS <NUM> may include an explicit indication of a quantity of transmission layers (e.g., <NUM> layer, <NUM> layers, and/or the like) for the SSB communication being transmitted on the particular beam. Alternatively, UE <NUM> may implicitly derive the quantity of transmission layers, such as based at least in part on a stored, default configuration.

As further shown in <FIG>, and by reference number <NUM>, BS <NUM> may transmit, to UE <NUM>, the SSB communications using spatial multiplexing. For example, BS <NUM> may, at a first time, transmit a first SSB communication on beam <NUM> and a second SSB communication on beam <NUM>. Similarly, at a second time, BS <NUM> may transmit a third SSB communication on beam <NUM> and a fourth SSB communication on beam <NUM>. Similarly, at a third time, BS <NUM> may transmit a fifth SSB communication on beam <NUM> and a sixth SSB communication on beam <NUM>. In this case, UE <NUM> may receive one or more of the SSB communications on one or more of the beams.

In some aspects, BS <NUM> may transmit one or more additional SSB communications that are not spatially multiplexed with another SSB communication. For example, at a fourth time, BS <NUM> may transmit a single SSB communication on a beam that has already been used (e.g., one of beams <NUM>-<NUM>), on a beam that has not been used (e.g., on a beam <NUM> or higher), and/or the like. In some aspects, BS <NUM> may associate the SSB communications with random access channel resources. For example, each beam (and each associated SSB communication) may have a corresponding random access channel resource (rather than a random access channel resource for each SSB communication occasion, in which multiple SSB communications may occur on multiple beams).

As further shown in <FIG>, and by reference number <NUM>, UE <NUM> may perform one or more measurements of the SSB communications. For example, UE <NUM> may perform a channel quality measurement, such as a reference signal received power (RSRP) measurement, a reference signal received quality (RSRQ) measurement, and/or the like. In this way, UE <NUM> may subsequently communicate with BS <NUM> in accordance with the one or more measurements of the SSB communications.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a BS, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where the BS (e.g., BS <NUM> and/or the like) performs operations associated with synchronization signal block transmission using spatial division multiplexing.

As shown in <FIG>, in some aspects, process <NUM> may include identifying, during a connected mode or an idle mode of a user equipment, a set of synchronization signal block communications, wherein the set of synchronization signal block communications includes two or more synchronization signal block communications (block <NUM>). For example, the BS (e.g., using transmit processor <NUM>, receive processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may identify, during a connected mode or an idle mode of a user equipment, a set of synchronization signal block communications, as described above. In some aspects, the set of synchronization signal block communications includes two or more synchronization signal block communications.

As further shown in <FIG>, in some aspects, process <NUM> may include transmitting the set of synchronization signal block communications using spatial multiplexing, wherein the set of synchronization signal block communications are each transmitted concurrently using different spatial resources associated with beam sweeping transmission (block <NUM>). For example, the BS (e.g., using transmit processor <NUM>, receive processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may transmit the set of synchronization signal block communications using spatial multiplexing, as described above. In some aspects, the set of synchronization signal block communications are each transmitted concurrently using different spatial resources associated with beam sweeping transmission.

In a first aspect, transmitting the set of synchronization signal block communications includes transmitting two or more sets of synchronization signal block communications, which include the set of synchronization signal block communications, using beam sweeping, wherein each set of synchronization signal block communications, of the two or more sets of synchronization signal block communications, includes two or more concurrently transmitted, spatially multiplexed synchronization signal block communications.

In a second aspect, alone or in combination with the first aspect, synchronization signal block communications, of the set of synchronization signal block communications, are associated with orthogonal demodulation reference signal sequences.

In a third aspect, alone or in combination with one or more of the first and second aspects, the orthogonal demodulation reference signal sequences are orthogonal with respect to at least one of: time, frequency, code, or a combination thereof.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, synchronization signal block communications, of the set of synchronization signal block communications, are associated with respective physical broadcast channel payloads that only differ with respect to respective synchronization signal block indices of the physical broadcast channel payloads.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, synchronization signal block communications, of the set of synchronization signal block communications, are associated with a common physical broadcast channel payload.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, process <NUM> includes transmitting at least one synchronization signal block communication, not in the set of synchronization signal block communications, that is not spatially multiplexed with any other synchronization signal block communication.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, process <NUM> includes transmitting signaling identifying spatial resources of the set of synchronization signal block communications.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the signaling is at least one of an indication in a physical broadcast channel, or an indication in connected mode radio resource control signaling.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the signaling explicitly indicates whether a synchronization signal block communication of the set of synchronization signal block communications is transmitted and implicitly indicates that the synchronization signal block communication is a two layer transmission.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the signaling explicitly indicates whether a synchronization signal block communication of the set of synchronization signal block communications is transmitted and explicitly indicates a quantity of transmission layers of the synchronization signal block communication.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, synchronization signal block occasions that include resources for the set of synchronization signal block communications are associated with corresponding random access channel resources.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, each random access channel resource, of the corresponding random access channel resources, corresponds to each spatially division multiplexed beam of each synchronization signal block communication of the set of synchronization signal block communications.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where the UE (e.g., UE <NUM> and/or the like) performs operations associated with synchronization signal block transmission using spatial division multiplexing.

As shown in <FIG>, in some aspects, process <NUM> may include receiving, during a connected mode or an idle mode and from a base station, signaling identifying spatial resources of a set of synchronization signal block communications, wherein the set of synchronization signal block communications includes two or more synchronization signal block communications (block <NUM>). For example, the UE (e.g., using receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may receive, during a connected mode or an idle mode and from a base station, signaling identifying spatial resources of a set of synchronization signal block communications, as described above. In some aspects, the set of synchronization signal block communications includes two or more synchronization signal block communications.

As further shown in <FIG>, in some aspects, process <NUM> may include receiving at least one of the set of synchronization signal block communications using spatial multiplexing corresponding to the spatial resources, wherein the set of synchronization signal block communications are each received concurrently using different spatial resources associated with beam sweeping transmission (block <NUM>). For example, the UE (e.g., using receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may receive at least one of the set of synchronization signal block communications using spatial multiplexing corresponding to the spatial resources, as described above. In some aspects, the set of synchronization signal block communications are each received concurrently using different spatial resources associated with beam sweeping transmission.

As further shown in <FIG>, in some aspects, process <NUM> may include determining, based at least in part on receiving the at least one of the set of synchronization signal block communications, a set of channel measurements (block <NUM>). For example, the UE (e.g., using receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may determine, based at least in part on receiving the at least one of the set of synchronization signal block communications, a set of channel measurements, as described above.

In a first aspect, the set of channel measurements includes a set of reference signal received power measurements.

In a second aspect, alone or in combination with the first aspect, process <NUM> includes communicating with the base station based at least in part on the set of channel measurements.

In a third aspect, alone or in combination with one or more of the first and second aspects, receiving the at least one of the set of synchronization signal block communications includes receiving at least one of two or more sets of synchronization signal block communications, which includes the set of synchronization signal block communications, using beam sweeping, wherein each set of synchronization signal block communications, of the two or more sets of synchronization signal block communications, includes two or more concurrently transmitted, spatially multiplexed synchronization signal block communications.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, synchronization signal block communications, of the set of synchronization signal block communications, are associated with orthogonal demodulation reference signal sequences.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the orthogonal demodulation reference signal sequences are orthogonal with respect to at least one of: time, frequency, code, or a combination thereof.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, synchronization signal block communications, of the set of synchronization signal block communications, are associated with respective physical broadcast channel payloads that only differ with respect to respective synchronization signal block indices of the physical broadcast channel payloads.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, synchronization signal block communications, of the set of synchronization signal block communications, are associated with a common physical broadcast channel payload.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, process <NUM> includes attempting to receive at least one synchronization signal block communication, not in the set of synchronization signal block communications, that is not spatially multiplexed with any other synchronization signal block communication.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the signaling is at least one of an indication in a physical broadcast channel, or an indication in connected mode radio resource control signaling.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the signaling explicitly indicates whether a synchronization signal block communication of the set of synchronization signal block communications is to be transmitted and implicitly indicates that the synchronization signal block communication is a two layer transmission.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the signaling explicitly indicates whether a synchronization signal block communication of the set of synchronization signal block communications is to be transmitted and explicitly indicates a quantity of transmission layers of the synchronization signal block communication.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, synchronization signal block occasions that include resources for the set of synchronization signal block communications are associated with corresponding random access channel resources.

In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, each random access channel resource, of the corresponding random access channel resources, corresponds to each spatially division multiplexed beam of each synchronization signal block communication of the set of synchronization signal block communications.

Claim 1:
A base station, BS (<NUM>), for wireless communication, comprising:
a memory; and
one or more processors operatively coupled to the memory, the memory comprising instructions which, when executed by the one or more processors, cause the one or more processors to:
identify (<NUM>), during a connected mode or an idle mode of a user equipment, UE (<NUM>), a set of synchronization signal block communications, wherein the set of synchronization signal block communications includes two or more synchronization signal block communications;
transmit signaling identifying spatial resources of the set of synchronization signal block communications, wherein the spatial resources correspond to one or more beams; and
transmit (<NUM>), based at least in part on the spatial resources, the set of synchronization signal block communications using spatial multiplexing, wherein the set of synchronization signal block communications are each transmitted concurrently using the spatial resources associated with beam sweeping transmission.