SSB structure for NR communications

In one aspect, an extended SSB (ESSB) is provided that includes more than four symbols to facilitate UE reception of SSBs. In this aspect, the base station configures an ESSB comprising an SSB including four symbols and an initial symbol preceding the SSB. The base station transmits and the UE receives at least a portion of the ESSB. The UE processes the ESSB. Thus, higher capacity UEs can benefit from additional coding gain in the initial symbol while lower capacity UEs can switch beams to receive back-to-back ESSBs. In another aspect, a UE performs additional behaviors to receive SSBs. In this aspect, the UE receives a first SSB using a reception beam, and the UE determines to maintain the reception beam for a second SSB or to switch the reception beam during a PSS symbol of the second SSB. Thus, lower capacity UEs can also receive back-to-back SSBs.

BACKGROUND

Technical Field

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

INTRODUCTION

SUMMARY

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The apparatus receives, from a base station, an extended synchronization signal block (ESSB), where the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB. The apparatus processes the ESSB.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The apparatus receives a first SSB using a reception beam. The apparatus determines to maintain the reception beam for a second SSB or to switch the reception beam during a primary synchronization signal (PSS) symbol of the second SSB.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a base station. The apparatus configures an ESSB, where the ESSB comprises an SSB including four symbols and an initial symbol preceding the SSB. The apparatus transmits to a UE at least a portion of the ESSB.

DETAILED DESCRIPTION

The UE may search for a cell of a base station for initial access (e.g. during a random access channel (RACH) procedure), for cell re-selection (e.g. during a handover), or for other purposes. To derive system information to access the cell, the UE may obtain a SSB including a PSS, a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The UE may also measure reference signal received power (RSRP) and reference signal receive quality (RSRQ) from the synchronization signals for other purposes (e.g. radio link monitoring (RLM) or radio resource management (RRM)).

The base station may transmit an SSB according to a configured periodicity. For example, the base station may transmit SSB periodically every 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, or 160 ms. The base station may also configure an SSB-based RRM Measurement Timing Configuration (SMTC) window informing the UE regarding an SSB measurement window periodicity and timing for SSB measurements. For example, the base station may configure the UE to measure SSBs periodically every 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, or 160 ms. The SMTC window periodicity may be the same as the SSB periodicity. The UE may receive and measure SSBs within each SMTC window and report measurements accordingly back to the base station.

To enable beam-sweeping for PSS, SSS and PBCH, the base station may also configure a SS burst set including a set of one or more SSBs, where each SSB in the SS burst set may potentially be transmitted on a different beam. The UE may similarly receive each SSB on a different beam. For instance, assuming an SSB periodicity of 20 ms or two 10 ms radio frames (and similarly an SMTC window periodicity of 20 ms), the base station may transmit an SSB burst set of one or more SSBs within a first-half or second-half of one of the radio frames (i.e. a 5 ms window within each 20 ms period), with each SSB being transmitted in a different beam. The base station may similarly configure the SMTC window duration to be the same as the SSB window (e.g. 5 ms). Thus, for example, the UE may receive and measure SSBs within a 5 ms window during each 20 ms period and report those measurements back to the base station.

The maximum number of candidate SSBs within each burst set may depend on the carrier frequency of the cell. For example, for frequencies above 6 GHz, at most 64 SSBs may be transmitted within a single SS burst set. Moreover, the starting OFDM symbol index for each candidate SSB within an SS burst set may depend on the carrier frequency of the cell and the subcarrier spacing (SCS). For example, for frequencies above 6 GHz, SSBs may be transmitted starting at OFDM symbols4,8,16, and20for 120 kHz SCS and starting at OFDM symbols8,12,16,20,32,36,40, and44for 240 kHz SCS. As each SSB generally includes four symbols, in multiple instances the SSBs may be transmitted back-to-back without gaps in between some of the SSBs.

Thus, patterns of SSBs may be configured which include at least some back-to-back SSBs, where each SSB may be transmitted and received on different beams in a given SS burst set. Depending on antenna capabilities, different base stations and UEs may switch their transmission and reception beams respectively for different SSBs within different periods of time. For example, a base station or UE that performs a beam switch instantaneously (or in less than 100 ns) may be considered a “high capability” base station or UE, while a base station or UE that requires at least 100 ns to perform a beam switch may be considered a “low capability” base station or UE. At lower numerologies (e.g. up to 120 kHz or 240 kHz SCS), the time within which the base station or UE may perform a beam switch may fall within a timing of a cyclic prefix (CP) for a back-to-back SSB, irrespective of whether the base station or UE is high or low capability. However, at higher frequency bands such as 52.6 GHz-71 GHz where higher numerologies such as 960 kHz SCS may be configured, the timing of the CP may no longer be sufficient for low capability base station and UE beam switching. For instance, CP timing at 960 kHz SCS may be less than 100 ns or otherwise less than the time required for a low capability base station or a low capability UE to perform beam switching for a back-to-back SSB. Although configuring a gap (e.g. an extra symbol) between such back-to-back SSBs may allow for low capability base station or UEs to successfully perform beam switching at such higher numerologies, such gaps may be inefficient for high capability base station or UEs that can adequately perform beam switching in the first place without such gaps.

To address this inefficiency, according to a first aspect of the disclosure, the base station may configure a different SSB structure that includes more than four symbols (e.g. five symbols). For example, the base station may configure an extended SSB (ESSB), which includes an additional symbol in comparison to the four symbol SSB described above. The additional symbol may be the initial symbol of the ESSB, thus preceding the SSB. The additional symbol may be a repetition of any of the other symbols in the four symbol SSB, thereby providing a coding gain in the ESSB relative to the SSB. The base station may also configure back-to-back, ESSBs (i.e. without gaps or intervening symbols between the ESSBs) with various time domain patterns. When the base station is a high capability base station that can beam switch without a gap between back-to-back ESSBs, the base station may transmit data in the additional symbol. Similarly, when the UE is a high capability UE that can beam switch without a gap between back-to-back ESSBs, the UE may receive data in the additional symbol. Otherwise, when the base station is a low capability base station, the base station may beam switch during a portion of the time period of the additional symbol (effectively using this portion as a gap between back-to-back ESSBs), or the base station may refrain from transmitting data in the additional symbol and instead use that time period to perform beam switching (as an actual gap between back-to-back ESSBs). Similarly, when the UE is a low capability UE, the UE may beam switch during a portion of the time period of the additional symbol (again effectively using this portion as a gap between back-to-back ESSBs), or the UE may ignore data received in the additional symbol and instead use that time period to perform beam switching (again as an actual gap between back-to-back ESSBs). Thus, high capability base station and UEs may benefit from the coding gain of back-to-back five symbol ESSBs, while low capability base station and UEs may still perform beam switching to receive such ESSBs without configuring hard gaps between such ESSBs.

Alternatively, according to a second aspect of the disclosure, if the base station is a high capability base station that can beam switch without gaps between back-to-back SSBs (i.e. four symbol SSBs), the base station may configure and transmit a four symbol SSB as previously described. While high capability UEs may successfully receive such SSBs since they can beam switch without gaps between back-to-back SSBs, low capability UEs may perform one or more additional behaviors to allow for reception of such SSBs. In one example, during initial access, the low capability UE may refrain from switching between back-to-back SSBs, and instead maintain the same reception beam between different SSBs. For SSBs which are not back-to-back and are thus separated by at least one intervening symbol, the UE may perform beam switching during the gap between those SSBs. In another example, during RLM or RRM, the low capability UE may beam switch during a symbol of the SSB which includes PSS (effectively using this PSS symbol as a gap between back-to-back SSBs), or the UE may refrain from switching between back-to-back SSBs and instead maintain the same reception beam. Alternatively, the low capability UE may not measure all back-to-back SSBs in a single SMTC window (e.g. the UE may measure a first SSB but not a second, subsequent SSB, or the UE may not measure any subsequent SSB, in the SMTC window). In such case, the base station may configure longer SMTC windows to allow the UE to monitor SSBs corresponding to different beams. Thus, low capability UEs may be able to receive four symbol SSBs without configuring hard gaps between such SSBs.

Referring again toFIG.1, in certain aspects, the UE104may include an SSB UE component198that is configured to receive, from a base station, an ESSB, where the ESSB comprises an SSB including four symbols and an initial symbol preceding the SSB, and to process the ESSB. The SSB UE component198is also configured to receive a first SSB using a reception beam, and determine to maintain the reception beam for a second SSB or to switch the reception beam during a PSS symbol of the second SSB.

Still referring toFIG.1, in certain aspects, the base station102/180may include an SSB BS component199that is configured to configure an ESSB, where the ESSB comprises an SSB including four symbols and an initial symbol preceding the SSB, and to transmit to a UE at least a portion of the ESSB.

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

At least one of the TX processor316, the RX processor370, and the controller/processor375may be configured to perform aspects in connection with SSB BS component199ofFIG.1.

The UE may search for a cell of a base station for initial access (e.g. during a RACH procedure), for cell re-selection (e.g. during a handover), or for other purposes. To derive system information to access the cell, the UE may obtain a SSB including a PSS, an SSS, and a PBCH. The UE may also measure RSRP and RSRQ from the synchronization signals for other purposes (e.g. RLM or RRM).

FIG.4illustrates an example400of a SSB402. The SSB402generally includes four consecutive symbols in the time domain and over 20 RBs (240subcarriers) in the frequency domain. A first symbol of the SSB402includes a PSS404, a second symbol of the SSB includes PBCH406, a third symbol of the SSB includes SSS408as well as PBCH406, and a fourth symbol of the SSB includes PBCH406. The PBCH406also includes demodulation reference signals (DMRS), which location may depend upon a primary cell indicator (PCI) of the cell based on PSS and SSS.

The base station may transmit an SSB according to a configured periodicity. For example, the base station may transmit SSB periodically every 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, or 160 ms. The base station may also configure an SMTC window informing the UE regarding an SSB measurement window periodicity and timing for SSB measurements. For example, the base station may configure the UE to measure SSBs periodically every 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, or 160 ms. The SMTC window periodicity may be the same as the SSB periodicity. The UE may receive and measure SSBs within each SMTC window and report measurements accordingly back to the base station.

To enable beam-sweeping for PSS, SSS and PBCH, the base station may also configure an SS burst set including a set of one or more SSBs, where each SSB in the SS burst set may potentially be transmitted on a different beam (e.g. a different one of the transmit directions182′ inFIG.1). The UE may similarly receive each SSB on a different beam (e.g. a different one of the receive directions182″ inFIG.1). For instance, assuming an SSB periodicity of 20 ms or two 10 ms radio frames (and similarly an SMTC window periodicity of 20 ms), the base station may transmit an SSB burst set of one or more SSBs within a first-half or second-half of one of the radio frames (i.e. a 5 ms window within each 20 ms period), with each SSB being transmitted in a different beam. The base station may similarly configure the SMTC window duration to be the same as the SSB window (e.g. 5 ms). Thus, for example, the UE may receive and measure SSBs within a 5 ms window during each 20 ms period and report those measurements back to the base station.

The maximum number of candidate SSBs (Lmax) within each burst set may depend on the carrier frequency of the cell. For example, for frequencies above 6 GHz, at most 64 SSBs may be transmitted within a single SS burst set. Moreover, the starting OFDM symbol index for each candidate SSB within an SS burst set may depend on the carrier frequency of the cell and the SCS. For example, for frequencies above 6 GHz, SSBs may be transmitted starting at OFDM symbols4,8,16, and20for 120 kHz SCS and starting at OFDM symbols8,12,16,20,32,36,40, and44for 240 kHz SCS. As each SSB generally includes four symbols, in multiple instances the SSBs may be transmitted back-to-back without gaps in between some of the SSBs.

FIG.5illustrates an example500of a timing of candidate SSBs502within an SS burst set having a configured SSB periodicity of 20 ms, a SCS of 120 kHz, and 64 candidate SSBs. In this example, each SSB502corresponds to a different beam (e.g. each SSB is transmitted in a different one of the transmit directions182′ ofFIG.1), in this case beams1,2,3, and4. Moreover, as illustrated, each 1 ms subframe at 120 kHz SCS may be divided into eight 0.125 ms slots, with each slot spanning 28 OFDM symbols. Furthermore, each SSB502may include four symbols (e.g. SSB402), where the starting symbol of each SSB begins at OFDM symbols4,8,16, and20. Thus, some of the SSBs502may be transmitted back-to-back without any gaps in between the SSBs. For example, the SSB starting at symbol4may be adjacent to the SSB starting at symbol8without an intervening symbol separating the SSBs. Similarly, the SSB starting at symbol16may be adjacent to the SSB starting at symbol20without an intervening symbol separating the SSBs. Similar back-to-back SSB patterns may be configured in other examples at other SCS (e.g. 240 kHz).

Thus, patterns of SSBs may be configured which include at least some back-to-back SSBs, where each SSB may be transmitted and received on different beams in a given SS burst set. Depending on antenna capabilities, different base stations and UEs may switch their transmission and reception beams respectively for different SSBs within different periods of time. For example, a base station or UE that performs a beam switch instantaneously (or in less than 100 ns) may be considered a “high capability” base station or UE, while a base station or UE that requires at least 100 ns to perform a beam switch may be considered a “low capability” base station or UE. At lower numerologies (e.g. up to 120 kHz or 240 kHz SCS), the time within which the base station or UE may perform a beam switch may fall within a timing of a CP for a back-to-back SSB, irrespective of whether the base station or UE is high or low capability. However, at higher frequency bands such as 52.6 GHz-71 GHz where higher numerologies such as 960 kHz SCS may be configured, the timing of the CP may no longer be sufficient for low capability base station and UE beam switching. For instance, CP timing at 960 kHz SCS may be less than 100 ns or otherwise less than the time required for a low capability base station or a low capability UE to perform beam switching for a back-to-back SSB. Although configuring a gap (e.g. an extra symbol) between such back-to-back SSBs may allow for low capability base station or UEs to successfully perform beam switching at such higher numerologies, such gaps may be inefficient for high capability base station or UEs that can adequately perform beam switching in the first place without such gaps.

To address this inefficiency, according to a first aspect of the disclosure, the base station may configure a different SSB structure that includes more than four symbols (e.g. five symbols). For example, the base station may configure an ESSB, which includes an additional symbol in comparison to the four symbol SSB described above. The additional symbol may be the first or initial symbol of the ESSB, thus preceding the SSB. The additional symbol may be a repetition of any of the other symbols in the four symbol SSB, thereby providing a coding gain in the ESSB relative to the SSB. The base station may also configure back-to-back, ESSBs (i.e. without gaps or intervening symbols between the ESSBs) with various time domain patterns. When the base station is a high capability base station that can beam switch without a gap between back-to-back ESSBs, the base station may transmit data in the additional symbol. Similarly, when the UE is a high capability UE that can beam switch without a gap between back-to-back ESSBs, the UE may receive data in the additional symbol. Otherwise, when the base station is a low capability base station, the base station may beam switch during a portion of the time period of the additional symbol (effectively using this portion as a gap between back-to-back ESSBs), or the base station may refrain from transmitting data in the additional symbol and instead use that time period to perform beam switching (as an actual gap between back-to-back ESSBs). Similarly, when the UE is a low capability UE, the UE may beam switch during a portion of the time period of the additional symbol (again effectively using this portion as a gap between back-to-back ESSBs), or the UE may ignore data received in the additional symbol and instead use that time period to perform beam switching (again as an actual gap between back-to-back ESSBs). Thus, high capability base station and UEs may benefit from the coding gain of back-to-back five symbol ESSBs, while low capability base station and UEs may still perform beam switching to receive such ESSBs without configuring hard gaps between such ESSBs.

Alternatively, according to a second aspect of the disclosure, if the base station is a high capability base station that can beam switch without gaps between back-to-back SSBs (i.e. four symbol SSBs), the base station may configure and transmit a four symbol SSB as previously described. While high capability UEs may successfully receive such SSBs since they can beam switch without gaps between back-to-back SSBs, low capability UEs may perform one or more additional behaviors to allow for reception of such SSBs. In one example, during initial access, the low capability UE may refrain from switching between back-to-back SSBs, and instead maintain the same reception beam between different SSBs. For SSBs which are not back-to-back and are thus separated by at least one intervening symbol, the UE may perform beam switching during the gap between those SSBs. In another example, during RLM or RRM, the low capability UE may beam switch during a symbol of the SSB which includes PSS (effectively using this PSS symbol as a gap between back-to-back SSBs), or the UE may refrain from switching between back-to-back SSBs and instead maintain the same reception beam. Alternatively, the low capability UE may not measure all back-to-back SSBs in a single SMTC window (e.g. the UE may measure a first SSB but not a second, subsequent SSB, or the UE may not measure any subsequent SSB, in the SMTC window). In such case, the base station may configure longer SMTC windows to allow the UE to monitor SSBs corresponding to different beams. Thus, low capability UEs may be able to receive four symbol SSBs without configuring hard gaps between such SSBs.

Now referring back to the first aspect (i.e. the ESSB) in one example, the base station may configure the ESSB such that the first or initial symbol (0) of the ESSB may include PBCH, with the remainder of the ESSB (the last four symbols) corresponding to the four symbol SSB described above. For instance,FIG.6illustrates an example600of an ESSB602where symbol0of the ESSB includes PBCH604, symbol1of the ESSB includes PSS606, symbol2of the ESSB includes PBCH604, symbol3of the ESSB includes SSS608and PBCH604, and symbol4of the ESSB includes PBCH604. In such case, the added PBCH symbol0may be a repetition of either PBCH in symbol2or4of the ESSB602, thereby providing PBCH coding gain for the UE, while the remaining symbols1-4of ESSB602match the corresponding symbols0-3of the SSB402inFIG.4. In another example, the base station may configure the ESSB such that symbol0of the ESSB includes a PSS, where the PSS is longer than the four symbol SSB described above (e.g. the PSS maps to both symbol0and1of the ESSB). In a further example, the base station may configure symbol0of the ESSB to include a PSS that is a repetition of the PSS of symbol1, but with different scrambling (e.g. a different cyclic shift). In an additional example, the base station may configure symbol0of the ESSB to include SSS and PBCH, where the SSS and PBCH are repeated in symbol3.

FIG.7illustrates various example patterns700of ESSBs702individually corresponding to different beams (e.g. beam1,2,3and4), where each ESSB702includes five symbols for 960 kHz SCS. In these examples, the base station may configure the time domain pattern of the ESSBs in a given SS burst set according to the starting symbol of each ESSB, although the base station may alternatively configure the ESSBs according to the ending symbol (or some other symbol) in other examples. For instance, as illustrated in the Figure, in one example (1), the base station may configure the starting symbols of the ESSBs to be 2, 7, 16, and 21, in another example (2), the base station may configure the starting symbols of the ESSBs to be 4, 9, 14, and 19, in a further example (3), the base station may configure the starting symbols of the ESSBs to be 4, 9, 18, and 23, and in an additional example (4), the base station may configure the starting symbols of the ESSBs to be 8, 13, 18, and 23. Thus, the base station may transmit, and the UE may receive, ESSBs including more than four symbols within a given SS burst set in any of the configured time domain patterns shown inFIG.7or in other configured patterns according to other examples. In these examples, each ESSB702may respectively correspond to ESSB602inFIG.6, with the starting symbol of each ESSB (e.g. symbol2in the first ESSB of example 1, symbol7in the second ESSB of example 1, etc.) being a repetition of the second symbol of each SSB (e.g. symbol4in the first ESSB of example 1, symbol9in the second ESSB of example 1, etc.). Moreover, in some examples the ESSBs may be configured such that a gap704exists between certain ESSBs (e.g. examples 1 and 3), while in other examples the ESSBs may be configured without such gaps (e.g. examples 2 and 4). Additionally, the symbols not used for transmitting ESSBs may be configured for general downlink or uplink data transmissions (e.g. symbols0,1,14, and15in example 1 may include PDCCH while symbols12,13,26, and27in example 1 may include uplink feedback). Furthermore, while the examples shown inFIG.7refer to 960 kHz, other SCS greater than 240 kHz may be configured in other examples.

When the base station is a high capability base station that can beam switch without a gap between back-to-back ESSBs, the base station may transmit all five symbols of the five symbol ESSB. For instance, referring to the first example illustrated inFIG.7, the base station may transmit in beam1all five symbols2-6of one of the ESSBs702, switch its transmission beam to beam2for a subsequent one of the ESSBs702(without a gap between symbol6and symbol7), and transmit in beam2all five symbols7-11of the subsequent one of the ESSBs. Otherwise, when the base station is a low capability base station, the base station may refrain from transmitting data in the initial symbol and instead use that time period to perform beam switching (as an actual gap between back-to-back ESSBs). For instance, referring to the first example illustrated inFIG.7, after transmitting one of the ESSBs702in symbols2-6using beam1, the base station may refrain from transmitting symbol7of a subsequent one of the ESSBs702, and instead utilize that time to switch its transmission beam to beam2for transmitting the remaining symbols8-11of the subsequent one of the ESSBs702. Alternatively, the low capability base station may beam switch during a portion of the time period of the initial symbol of the ESSB (effectively using this portion as a gap between back-to-back ESSBs). In other words, the base station may partially transmit data in the initial symbol of the ESSB, rather than refraining from transmitting data in the initial symbol altogether. For instance, referring to the first example illustrated inFIG.7, if symbol7of the subsequent one of the ESSBs702spans 1000 ns in 960 kHz SCS, then the base station may perform beam switching during the first 100 ns of symbol7and afterwards transmit ESSB data (e.g. PBCH, PSS, or SSS) within the remaining 900 ns of symbol7, as opposed to skipping transmission of data in symbol7altogether.

Similarly, when the UE is a high capability UE that can beam switch without a gap between back-to-back ESSBs, the UE may receive all five symbols of the ESSB. For instance, referring the first example illustrated inFIG.7, the UE may receive in beam1all five symbols2-6of one of the ESSBs702, switch its reception beam to beam2for a subsequent one of the ESSBs702(without a gap between symbol6and symbol7), and receive in beam2all five symbols7-11of the subsequent one of the ESSBs. However, during initial access, the UE may not be informed of whether the base station is a high capability base station or a low capability base station. Thus, in some cases the UE may not be informed of whether the base station has fully transmitted, partially transmitted, or not transmitted data (e.g. in PBCH) in the initial symbol of an ESSB.

As a result, such high capability UEs may perform one of multiple behaviors with respect to the received ESSB. In a first option, the UE may disregard or ignore the expected initial symbol of the ESSB and effectively process the ESSB as a four symbol SSB, although the UE may fail to benefit from any coding gains in the initial symbol from SSB data repetition as a result. For instance, referring to the first example illustrated inFIG.7, the UE may refrain from decoding symbol2of one of the ESSBs702and only decode symbols3-7of that ESSB to identify MIB in PBCH. In a second option, the UE may perform blind decoding of PBCH based on different hypotheses (i.e. based on one assumption that the received ESSB includes four symbols and again based on another assumption that the received ESSB includes five symbols), and the UE may determine which hypothesis is correct in response to a successful decoding of the PBCH. For instance, referring to the first example illustrated inFIG.7, the UE may attempt to decode only symbols3-6of one of the ESSBs702to determine a first log likelihood ratio (LLR) of data in PBCH, attempt to decode symbols2-6of the same ESSB to determine a second LLR of data in PBCH, compare the first and second LLRs to determine which value indicates more confidence (e.g. which of the two LLRs is closer to 0 or closer to 1), and then determine whether symbol2(the initial symbol) was transmitted or not based on the comparison. For example, if the first LLR indicates more confidence, the UE may conclude that only a four symbol SSB was transmitted (e.g., symbol2of the ESSB702in example 1 did not include PBCH and thus was not transmitted), while if the second LLR indicates more confidence, the UE may conclude that a five symbol ESSB was transmitted (e.g., symbol2of the ESSB702in example 1 included PBCH, and thus was transmitted). In a third option, the UE may attempt to detect DMRS in PBCH within an expected initial symbol of the ESSB, in response to which the UE may determine whether the initial symbol of the ESSB was actually transmitted. For instance, referring to the first example illustrated inFIG.7, the UE may attempt to decode DMRS in symbol2of one of the ESSBs702, and if the UE successfully decodes DMRS, the UE may determine that a five symbol ESSB was transmitted and the UE may decode the ESSB accordingly; otherwise, the UE may determine that only a four symbol SSB was transmitted and the UE may decode the SSB accordingly. In a fourth option, the UE may assume the expected initial symbol of the ESSB is fully transmitted and demodulate data (e.g. PBCH, PSS, or SSS) within the symbol accordingly. For instance, referring to the first example illustrated inFIG.7, the UE may attempt to decode symbol2of the one of the ESSBs702for a repeated PBCH without previously determining whether SSB data in the initial symbol was transmitted in the first place. In a fifth option, the UE may detect DMRS in PBCH within the four symbol SSB for channel estimation, and identify LLRs of the initial symbol to determine whether the initial symbol of the ESSB was actually or partially transmitted. For instance, referring to the first example illustrated inFIG.7, the UE may decode DMRS in symbols3-6of one of the ESSBs702, perform channel estimation (e.g. identify a channel quality indicator (CQI) or other channel state information report parameters) using the DMRS and identify a first LLR for PBCH, attempt to decode symbol2of the same ESSB to determine a second LLR for PBCH, combine the first and second LLRs, and determine whether symbol2(the initial symbol) was transmitted or not based on the combined LLRs. For example, if the combined LLRs indicate less confidence than the first LLR, the UE may conclude that only a four symbol SSB was transmitted (e.g., symbol2of the ESSB702in example 1 did not include PBCH and thus was not transmitted), while if the combined LLRs indicate more confidence, the UE may conclude that a five symbol ESSB was transmitted (e.g., symbol2of the ESSB702in example 1 included PBCH, and thus was transmitted). In contrast to the fourth option, this fifth option avoids channel estimation loss in the event data was partially transmitted in the initial symbol of the ESSB, although both options allow the UE to receive data in the initial symbol even when partially transmitted.

When the UE is a low capability UE, the UE typically takes at least a certain period of time (e.g. at least a 100 ns gap between back-to-back SSBs) to perform a beam switch. Accordingly, in one example, the UE may beam switch during a portion of the time period of the initial symbol of the ESSB (effectively using this portion as a gap between back-to-back ESSBs). For instance, referring to the first example illustrated inFIG.7, the UE may perform beam switching from beam1to beam2at least partially within symbol7of one of the ESSBs702. For example, if symbol7of this ESSB spans 1000 ns in 960 kHz SCS, then the UE may perform beam switching during the first 100 ns of symbol7and afterwards capture a majority of the samples of ESSB data (e.g. PBCH, PSS, or SSS) within the remaining 900 ns of symbol7. In another example, the UE may refrain from beam switching between back-to-back ESSBs to benefit from the coding gain which results from the additional symbol of the ESSB relative to the SSB. For instance, referring to the first example illustrated inFIG.7, in some cases such as initial access the UE may maintain its reception beam (e.g. beam1) between symbols6and7of the back-to-back ESSBs, rather than switching to beam2as illustrated in the Figure. Additionally, in some cases the UE may not be informed of whether the base station has fully transmitted, partially transmitted, or not transmitted data (e.g. in PBCH) in the initial symbol of an ESSB. Accordingly, the low capability UE may similarly perform one of the five options described above with respect to high capability UEs, although such low capability UEs may not be able to benefit from fully transmitted initial symbols of an ESSB in contrast to high capability UEs.

In cases where the UE is in a connected mode, for example, in cases of carrier aggregation (CA), dual connectivity (DC), or inter-cell RRM, the base station may indicate whether the base station is high capability or low capability to the UE. For example, the base station may provide RRC signaling (e.g. an RRC configuration, message, or other indication) to the UE indicating a number of symbols of the ESSB (e.g. four or five symbols), a time domain pattern of the ESSB (e.g. the starting symbols of each ESSB repeating within a periodic SS burst set), or a partial transmission/reception of the initial symbol of the ESSB (e.g. a bit or other indication identifying whether data in the initial symbol will be fully or partially transmitted). This signaling may include similar information for neighbor base stations as well as serving base stations. Moreover, the indication may be transmitted in dedicated signaling (e.g. unicast) to the UE to assist the UE in performing RLM or RRM, although the indication may be alternatively or additionally broadcast or multicast to the UE in other examples. Additionally, the indication may quantify the amount of data the base station may partially transmit within the initial symbol of the ESSB when the base station performs beam switching during the initial symbol (e.g. the base station may indicate to the UE that ESSB data will be transmitted within 900 ns of a 1000 ns initial symbol for 960 kHz, or within 90% of the initial symbol).

Additionally, the base station may select an SSB pattern (e.g. a pattern of either four symbol SSBs or five symbol ESSBs) based on whether the base station is high capability or low capability. For instance, if the base station is a high capability base station, the base station may select to transmit either four symbol SSBs or five symbol ESSBs, while if the base station is a low capability base station, the base station may only transmit five symbol ESSBs. Moreover, the SSB pattern may be selected depending on whether the base station is a standalone (SA) base station or a non-standalone (NSA) base station. An SA base station refers to a base station that is directly connected to a core network (e.g. core network190) and may receive and transmit control plane data to the UE. A non-standalone (NSA) base station refers to a base station that is connected to another base station, which in turn, is connected to a different RAT network (e.g. EPC160) and which receives and transmits control plane data to the UE. For example, in NSA, control signaling of 5G may be anchored to a 4G base station, while in SA, a 5G base station may be directly connected to a 5G core network without depending on the 4G network for control signaling. If the base station is an SA base station, the base station may only transmit five symbol ESSBs so that UEs during initial access may assume that only one type of SSB (i.e. ESSB) may be received. If the base station is an NSA base station, the base station may select to transmit either four symbol SSBs or five symbol EESBs depending on whether the base station is high capability or low capability as described above. In such case, the different RAT base station connected to the NSA base station may also signal to the UE an indication of the selected pattern (i.e. SSBs or ESSBs).

Now referring to the second aspect of the disclosure (e.g. four symbol SSB), when the base station is a high capability base station that can beam switch without gaps between back-to-back SSBs (i.e. four symbol SSBs), the base station may configure and transmit a four symbol SSB as previously described. While high capability UEs may successfully receive such SSBs since they can beam switch without gaps between back-to-back SSBs, low capability UEs may perform one or more additional behaviors to allow for reception of such SSBs. In one example, during initial access (when the UE is detecting PSS), the low capability UE may refrain from switching between back-to-back SSBs, and instead maintain the same reception beam between different SSBs. For instance, referring toFIG.5, after receiving one of the SSBs502in symbols4-7using beam1, the UE may maintain the same reception beam (e.g. beam1) for receiving a subsequent one of the SSBs502in symbols8-11, rather than switching to beam2as illustrated. Alternatively, the UE may refrain from decoding back-to-back SSBs. For instance, referring toFIG.5, the UE may skip decoding the subsequent one of the SSBs502in symbols8-11since that SSB is back-to-back with the SSB in symbols4-7. For SSBs which are not back-to-back and are thus separated by at least one intervening symbol, the UE may perform beam switching during the gap between those SSBs. For instance, referring toFIG.5, after receiving one of the SSBs502in symbols8-11using beam2, the UE may switch to beam3to receive a subsequent one of the SSBs502in symbols16-19, since the two SSBs are separated by a gap (e.g. symbols12-15).

In another example, during RLM or RRM (e.g. where the UE may measure received power from SSS or DMRS in PBCH) if the UE does not use PSS for RLM/RRM measurement, the low capability UE may beam switch during a symbol of the SSB which includes PSS (effectively using this PSS symbol as a gap between back-to-back SSBs). For instance, referring toFIG.5, after receiving one of the SSBs502in symbols4-7using beam1, the UE may switch to beam2during the PSS symbol (e.g. symbol8) of the subsequent one of the SSBs502. Thus, the UE may not decode the PSS symbol of that SSB when the UE is not measuring the PSS.

Alternatively, if the UE uses PSS for RLM/RRM measurement, in one example, the UE may refrain from switching between back-to-back SSBs and instead maintain the same reception beam. For instance, referring toFIG.5, after receiving one of the SSBs502in symbols4-7using beam1, the UE may maintain the same reception beam (e.g. beam1) for receiving a subsequent one of the SSBs502in symbols8-11, rather than switching to beam2as illustrated. Alternatively, in another example, the low capability UE may not measure all back-to-back SSBs in a single SMTC window (e.g. the UE may measure a first SSB but not a second, subsequent SSB, or the UE may not measure any subsequent SSB, in the SMTC window). For instance, referring toFIG.5, if the base station configures the SMTC window to be a certain period of time for SSB measurements (e.g. 5 ms), the UE may maintain the same reception beam (e.g. beam1) for receiving subsequent ones of the SSBs502during that 5 ms time (e.g. in symbols8-11,16-19, and20-23, and so forth), rather than switching beams prior to each SSB as illustrated, and the UE may refrain from measuring the subsequent ones of the SSBs if any of these SSBs are received in the maintained reception beam. The base station may also configure longer SMTC windows (e.g. longer than 5 ms in this example) to allow the UE to monitor SSBs corresponding to different beams. Thus, low capability UEs may be able to receive four symbol SSBs without configuring hard gaps between such SSBs.

FIG.8is an example800of a call flow between a UE802and a base station804. Optional aspects are illustrated in dashed lines. At806, the base station804configures an ESSB808. The ESSB comprises a SSB810including four symbols and an initial symbol812preceding the SSB810. For example, referring toFIGS.4and6, the base station may configure an ESSB602, which comprises a SSB including four symbols (symbols1-4corresponding to symbols0-3of SSB402) and an additional symbol0occurring in time before the SSB. The initial symbol0may include PBCH604as illustrated in the example ofFIG.6, or may include PSS606or SSS608in other examples. The base station may also configure an ESSB periodicity, an SMTC window for measuring ESSBs, and a beam corresponding to each ESSB within a SS burst set including multiple ESSBs. After configuring the ESSB808, the base station804may transmit the ESSB808(including the SSB810and initial symbol812) to the UE802within symbols of a slot of a subframe (e.g. at 960 kHz SCS or at another SCS above 240 kHz) along with other ESSBs in a time domain pattern during periodic SS burst sets.

Additionally, the base station804may configure other information relating to the ESSB, and the base station may transmit an indication814of this information to the UE802prior to transmitting the ESSB808. For instance, the base station may indicate a number of symbols816for the ESSB808. For example, referring toFIG.6, the base station may indicate that the ESSB602includes five symbols. The base station may also indicate a time domain pattern818for the ESSB808. For example, referring toFIG.7, the base station may indicate starting symbols corresponding to any one of the various example patterns700inFIG.7of ESSBs702. The base station may also indicate whether a partial transmission820or reception of the initial symbol812of the ESSB808is to occur. For example, referring toFIG.7, the base station may indicate to the UE that the base station will perform a beam switch partially within an initial symbol of one of the ESSBs702. The base station may also indicate a quantity822associated with the partial transmission820or reception of the initial symbol812. For example, referring toFIG.7, the base station may indicate that ESSB data will be transmitted partially within the initial symbol of one of the ESSBs702(e.g. within 900 ns out of a 1000 ns initial symbol). The base station may transmit one or any combination of this information to the UE in indication814(or in multiple indications).

Moreover, when configuring the ESSB at806, the base station804may select an SSB pattern (e.g. to transmit ESSB808without initial symbol812, i.e. only SSB810, or to transmit the ESSB808with all five symbols) based on whether the base station is high capability or low capability. For instance, if the base station is a high capability base station, the base station may select to configure and transmit ESSB808with or without initial symbol812(i.e. an ESSB of four or five symbols), while if the base station is a low capability base station, the base station may only configure and transmit ESSB808with initial symbol812(i.e. an ESSB of five symbols). Moreover, if the base station is an SA base station, the base station may only configure and transmit ESSBs with initial symbol812(i.e. an ESSB of five symbols). If the base station is an NSA base station, the base station may select to configure and transmit ESSB808with or without initial symbol812(i.e. an ESSB of four or five symbols) depending on whether the base station is high capability or low capability as described above. In such cases where the base station selects between ESSBs with or without the initial symbols, the base station may also signal to the UE an indication of the selected pattern (i.e. an ESSB of four or five symbols), for example, in indication814or in a separate indication.

At824, the base station804may refrain from transmitting the initial symbol812of the ESSB808. For example, when the base station is a low capability base station, the base station may refrain from transmitting data in the initial symbol and instead use that time period to perform beam switching (as an actual gap between back-to-back ESSBs). For instance, referring to the first example illustrated inFIG.7, after transmitting one of the ESSBs702in symbols2-6using beam1, the base station may refrain from transmitting symbol7of a subsequent one of the ESSBs702, and instead utilize that time to switch its transmission beam to beam2for transmitting the remaining symbols8-11of the subsequent one of the ESSBs702. Alternatively at826, the base station804may switch a transmission beam during a time period for transmitting the initial symbol812of the ESSB808. For example, the low capability base station may beam switch during a portion of the time period of the initial symbol of the ESSB (effectively using this portion as a gap between back-to-back ESSBs). In other words, the base station may partially transmit data in the initial symbol of the ESSB, rather than refraining from transmitting data in the initial symbol altogether. For instance, referring to the first example illustrated inFIG.7, if symbol7of the subsequent one of the ESSBs702spans 1000 ns in 960 kHz SCS, then the base station may perform beam switching during the first 100 ns of symbol7and afterwards transmit ESSB data (e.g. PBCH, PSS, or SSS) within the remaining 900 ns of symbol7, as opposed to skipping transmission of data in symbol7altogether.

At828, the UE802may refrain from decoding the initial symbol812of the ESSB808. For example, when the UE802is a high capability UE that is not informed of whether the base station804has fully transmitted, partially transmitted, or not transmitted data in the initial symbol812of ESSB808(e.g. if the UE does not receive indication814, or if indication814does not indicate whether a partial transmission820of the initial symbol812of the ESSB808is to occur), the UE may disregard or ignore the expected initial symbol of the ESSB and effectively process the ESSB as a four symbol SSB according to the first behavioral option described above. For instance, referring to the first example illustrated inFIG.7, the UE may refrain from decoding symbol2of one of the ESSBs702and only decode symbols3-6of that ESSB to identify MIB in PBCH. The UE may similarly perform this option if the UE is a low capability UE.

At830, the UE802may determine that the ESSB808includes more than four symbols (e.g. that the ESSB808includes initial symbol812). For example, when the UE802is a high capability UE that is not informed of whether the base station804has fully transmitted, partially transmitted, or not transmitted data in the initial symbol812of ESSB808(e.g. if the UE does not receive indication814, or if indication814does not indicate the number of symbols816for the ESSB or similar information), the UE may determine that ESSB808is received (rather than only SSB810) according to one of the second, third, or fifth behavioral options described above. In one example (i.e. the second above-described option), the UE may perform blind decoding of PBCH based on different hypotheses (i.e. based on one assumption that the received ESSB includes four symbols and again based on another assumption that the received ESSB includes five symbols), and the UE may determine which hypothesis is correct in response to a successful decoding of the PBCH. In another example (i.e. the third above-described option), the UE may attempt to detect DMRS in PBCH within an expected initial symbol of the ESSB, in response to which the UE may determine whether the initial symbol of the ESSB was actually transmitted. In a further example (i.e. the fifth above-described option), the UE may detect DMRS in PBCH within the four symbol SSB for channel estimation, and identify LLRs of the initial symbol to determine whether the initial symbol of the ESSB was actually or partially transmitted. The UE may similarly perform any of these options if the UE is a low capability UE.

At832, the UE802may decode the initial symbol812of the ESSB808without determining whether the ESSB808includes more than four symbols. For example, when the UE802is a high capability UE that is not informed of whether the base station804has fully transmitted, partially transmitted, or not transmitted data in the initial symbol812of ESSB808(e.g. if the UE does not receive indication814, or if indication814does not indicate the number of symbols816for the ESSB or similar information), the UE may decode initial symbol812according to the fourth behavioral option described above. For example, the UE may assume the expected initial symbol of the ESSB is fully transmitted and demodulate data (e.g. PBCH, PSS, or SSS) within the symbol accordingly. The UE may similarly perform this option if the UE is a low capability UE.

At834, the UE802may switch a reception beam (e.g. one of the receive directions182″) during a time period for receiving the initial symbol812of the ESSB808. For example, when the UE802is a low capability UE, the UE may beam switch during a portion of the time period of the initial symbol812of the ESSB808(effectively using this portion as a gap between back-to-back ESSBs). For instance, referring to the first example illustrated inFIG.7, the UE may perform beam switching from beam1to beam2at least partially within symbol7of one of the ESSBs702. For example, if symbol7of this ESSB spans 1000 ns in 960 kHz SCS, then the UE may perform beam switching during the first 100 ns of symbol7and afterwards capture a majority of the samples of ESSB data (e.g. PBCH, PSS, or SSS) within the remaining 900 ns of symbol7. Alternatively, at836, the UE802may maintain a reception beam (e.g. one of the receive directions182″) between a time for receiving the ESSB808and a subsequent time for receiving a subsequent ESSB. For example, when the UE802is a low capability UE, the UE may refrain from beam switching between back-to-back ESSBs. For instance, referring to the first example illustrated inFIG.7, in some cases such as initial access the UE may maintain its reception beam (e.g. beam1) between symbols6and7of the back-to-back ESSBs, rather than switching to beam2as illustrated in the Figure.

Finally, at838, the UE802may process the ESSB808. For example, referring toFIG.6, the UE may decode ESSB602and detect PSS606and SSS608and MIB in PBCH604, and the UE may obtain initial access to the base station804(e.g. perform a RACH procedure) based on the detected information. The UE may also perform RLM/RRM measurements, handovers, channel estimation, or other procedures using the PSS606, SSS608, DMRS in PBCH604, or other data in the ESSB602.

FIG.9is another example900of a call flow between a UE902and a base station904. Optional aspects are illustrated in dashed lines. The UE902receives a first SSB906using a reception beam (e.g. in one of the receive directions182″). For example, referring toFIG.5, the UE may receive one of the SSBs502in symbols4-7using beam1. The UE also receives a second SSB908subsequent to the first SSB906. For example, referring toFIG.5, the UE may receive a subsequent one of the SSBs502in symbols8-11.

At910, the UE determines to maintain the reception beam for the second SSB908or to switch the reception beam during a PSS symbol of the second SSB908. For example, if the UE is a low capability UE, the UE may refrain from switching between back-to-back SSBs (e.g. the one of the SSBs502in symbols4-7and the subsequent one of the SSBs502in symbols8-11inFIG.5), and instead maintain the same reception beam between different SSBs (e.g. receive both SSBs502using beam1). In another example, the UE may perform beam switching during a gap between SSBs (e.g. during symbols12-15between the subsequent one of the SSBs502and a third one of the SSBs502in symbols16-19), or during a symbol of the SSB which includes PSS (e.g. during symbol8in the subsequent one of the SSBs502, which may include PSS404). Additional details are described below with respect to912,914,916, and918for such low capability UEs.

In one example, at912, the UE may switch the reception beam during the PSS symbol. For instance, during RLM or RRM (e.g. where the UE may measure received power from SSS or DMRS in PBCH) if the UE does not use PSS for RLM/RRM measurement, the low capability UE may beam switch during a symbol of the SSB which includes PSS (effectively using this PSS symbol as a gap between back-to-back SSBs). For instance, referring toFIG.5, after receiving one of the SSBs502in symbols4-7using beam1, the UE may switch to beam2during the PSS symbol (e.g. symbol8) of the subsequent one of the SSBs502. Thus, the UE may not decode the PSS symbol of that SSB when the UE is not measuring the PSS.

In another example, at914, the UE may maintain the reception beam between the first SSB906and the second SSB908. For instance, if the UE uses PSS for RLM/RRM measurement, in one example, the UE may refrain from switching between back-to-back SSBs and instead maintain the same reception beam. For instance, referring toFIG.5, after receiving one of the SSBs502in symbols4-7using beam1, the UE may maintain the same reception beam (e.g. beam1) for receiving a subsequent one of the SSBs502in symbols8-11, rather than switching to beam2as illustrated.

In another example, at916, the UE may refrain from decoding the second SSB908. For instance, during initial access, the UE may refrain from decoding back-to-back SSBs. For example, referring toFIG.5, the UE may skip decoding the subsequent one of the SSBs502in symbols8-11since that SSB is back-to-back with the SSB in symbols4-7. The UE may also refrain from decoding the second SSB during a SMTC window. For instance, the low capability UE may not measure all back-to-back SSBs (e.g. subsequent SSBs) in a single SMTC window. Moreover, referring toFIG.5, if the base station configures the SMTC window to be a certain period of time for SSB measurements (e.g. 5 ms), the UE may maintain the same reception beam (e.g. beam1) for receiving subsequent ones of the SSBs502during that 5 ms time (e.g. in symbols8-11,16-19, and20-23, and so forth), rather than switching beams prior to each SSB as illustrated.

In an additional example, at918, the UE may switch the reception beam during a gap between the second SSB and a third SSB. For instance, for SSBs which are not back-to-back and are thus separated by at least one intervening symbol, the UE may perform beam switching during the gap between those SSBs. For instance, referring toFIG.5, after receiving the subsequent one of the SSBs502in symbols8-11using beam2, the UE may switch to beam3to receive an additional one of the SSBs502in symbols16-19, since the two SSBs are separated by a gap (e.g. symbols12-15).

While various features or examples have been described in association with specific aspects (e.g., a first aspect relating to ESSBs inFIG.8and a second aspect relating to four symbol SSBs inFIG.9), these features or examples are not limited to their respective aspects. Moreover, any of the above-described features, examples or aspects may be combined or used together with any other aforementioned feature, example or aspect. For instance, a UE or base station may perform any of the steps described above with respect toFIG.8in combination with any of the steps described above with respect toFIG.9. Thus, any of the features, examples or aspects described above may be combined to form additional features, examples or aspects without departing from the scope of the present disclosure.

FIG.10is a flowchart1000of a method of wireless communication. The method may be performed by a UE (e.g., the UE104,350,802,902; the apparatus1302) in communication with a base station. Optional aspects are illustrated in dashed lines. The method allows for high capability UEs to benefit from the coding gain of back-to-back five symbol ESSBs, while also allowing for low capability UEs to perform beam switching to receive such ESSBs without configuring hard gaps between the ESSBs.

At1002, the UE may receive an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial reception of the initial symbol of the ESSB. For example,1002may be performed by indication component1340. For instance, referring toFIG.8, the UE802may receive indication814of the number of symbols816of ESSB808, the time domain pattern818of ESSBs, or whether the partial transmission820of ESSB data in initial symbol812is to occur. The indication may be for the base station (e.g. relating to ESSBs from base station804) or another base station (e.g. relating to ESSBs from a neighbor base station). The indication may be received in dedicated signaling (e.g. unicast). The indication may include a quantity (e.g. quantity822) associated with the partial reception of the initial symbol of the ESSB.

The UE may also receive, at1002, an SSB indication that the ESSB includes more than four symbols when the base station is a NSA base station. Alternatively, the base station may be a SA base station. For instance, referring toFIG.8, the indication814(or a separate indication) may indicate that ESSB808includes more than four symbols (e.g. initial symbol812and SSB810) when base station804is a NSA base station. Alternatively, base station804may be a SA base station.

At1004, the UE receives, from the base station, an ESSB, where the ESSB comprises a SSB including four symbols and an initial symbol preceding the SSB. For example,1004may be performed by ESSB component1342. For instance, referring toFIG.8, the UE802may receive ESSB808including SSB810and initial symbol812preceding the SSB. The initial symbol may include a PBCH (e.g. PBCH604as illustrated in the example ofFIG.6), a PSS (e.g. PSS606), or a SSS (e.g. SSS608). The initial symbol may be a repetition of one of the symbols of the SSB (e.g. a repetition of PBCH, PSS, or SSS in SSB402,810). A final symbol of the ESSB may be adjacent to an initial symbol of a second ESSB (e.g. the ESSBs are back-to-back). For instance, as shown in the first example ofFIG.7, final symbol6of one of the ESSBs702for beam1may be adjacent to initial symbol7of another of the ESSBs702for beam2. The ESSB may be received in a pattern associated with a subcarrier spacing greater than 240 kHz (e.g. 960 kHz SCS).

At1006, the UE may refrain from decoding the initial symbol of the ESSB. For example,1006may be performed by decode component1344. For instance, referring toFIG.8, at828, the UE802may refrain from decoding initial symbol812of ESSB808according to the first behavioral option described above (e.g. effectively processing the ESSB as a four symbol SSB).

At1008, the UE may determine that the ESSB includes more than the four symbols in response to successfully decoding the ESSB. For example,1008may be performed by determination component1346. For instance, referring toFIG.8, at830, the UE802may determine that the ESSB808includes more than four symbols (e.g. that the ESSB808includes initial symbol812) according to the second behavioral option described above (e.g. based on blind decoding of PBCH based on different hypotheses).

At1010, the UE may determine that the ESSB includes more than the four symbols in response to detecting a DMRS in the initial symbol of the ESSB. For example,1010may be performed by the determination component1346. For instance, referring toFIG.8, at830, the UE802may determine that the ESSB808includes more than four symbols (e.g. that the ESSB808includes initial symbol812) according to the third behavioral option described above (e.g. based on detection of DMRS in PBCH within the initial symbol of the ESSB).

At1012, the UE may decode the initial symbol of the ESSB without determining the ESSB includes more than the four symbols. For example,1012may be performed by the decode component1344. For instance, referring toFIG.8, at832, the UE802may decode the initial symbol812of the ESSB808without determining whether the ESSB808includes more than four symbols according to the fourth behavioral option described above (e.g. based on an assumption that data in the initial symbol of the ESSB has been fully transmitted).

At1014, the UE may determine that that the ESSB includes more than the four symbols based on channel estimation from a DMRS in the SSB. For example,1014may be performed by the determination component1346. For instance, referring toFIG.8, at830, the UE802may determine that the ESSB808includes more than four symbols (e.g. that the ESSB808includes initial symbol812) according to the fifth behavioral option described above (e.g. based on detection of DMRS in PBCH within the SSB810for channel estimation).

At1016, the UE may switch a reception beam during a time period for receiving the initial symbol of the ESSB. For example,1016may be performed by beam component1348. For instance, referring toFIG.8, at834, the UE802may switch a reception beam (e.g. one of the receive directions182″) during a time period for receiving the initial symbol812of the ESSB808.

At1018, the UE may maintain a reception beam between a time for receiving the ESSB and a subsequent time for receiving a second ESSB. For example,1018may be performed by the beam component1348. For instance, referring toFIG.8, at836, the UE802may maintain a reception beam (e.g. one of the receive directions182″) between a time for receiving the ESSB808and a subsequent time for receiving a subsequent ESSB.

Finally, at1020, the UE processes the ESSB. For example,1020may be performed by process component1350. For instance, referring toFIG.8, at838, the UE802may process the ESSB808.

FIG.11is a flowchart1100of a method of wireless communication. The method may be performed by a UE (e.g., the UE104,350,802,902; the apparatus1302) in communication with a base station. Optional aspects are illustrated in dashed lines. The method allows for low capability UEs to be able to receive four symbol SSBs without configuring hard gaps between such SSBs.

At1102, the UE receives a first SSB using a reception beam. For example,1102may be performed by SSB component1352. For instance, referring toFIG.9, the UE902may receive a first SSB906using a reception beam (e.g. in one of the receive directions182″).

At1104, the UE determines to maintain the reception beam for a second SSB or to switch the reception beam during a PSS symbol of the second SSB. For example,1104may be performed by the determination component1346. For instance, referring toFIG.9, at910, the UE902may determine to maintain the reception beam for the second SSB908or to switch the reception beam during a PSS symbol of the second SSB908.

At1106, the UE may switch the reception beam during the PSS symbol. For example,1106may be performed by the beam component1348. For instance, referring toFIG.9, at912, the UE902may switch the reception beam during the PSS symbol.

At1108, the UE may maintain the reception beam between the first SSB and the second SSB. For example,1108may be performed by the beam component1348. For instance, referring toFIG.9, at914, the UE902may maintain the reception beam between the first SSB906and the second SSB908.

At1110, the UE may refrain from decoding the second SSB. For example,1110may be performed by the decode component1344. For instance, referring toFIG.9, at916, the UE902may refrain from decoding the second SSB908. The UE may also refrain from decoding, at1110, the second SSB during a SMTC window (e.g. at916inFIG.9).

Finally, at1112, the UE may switch the reception beam during a gap between the second SSB and a third SSB. For example,1112may be performed by the beam component1348. For instance, referring toFIG.9, at918, the UE902may switch the reception beam during a gap between the second SSB908and a third SSB.

FIG.12is a flowchart1200of a method of wireless communication. The method may be performed by a base station (e.g., the base station102/180,310,804,904; the apparatus1402). Optional aspects are illustrated in dashed lines. The method allows for high capability base stations to benefit from the coding gain of back-to-back five symbol ESSBs, while also allowing for low capability base stations to perform beam switching to transmit such ESSBs without configuring hard gaps between the ESSBs.

At1202, the base station configures an ESSB, where the ESSB comprises a SSB including four symbols and an initial symbol preceding the SSB. For example,1202may be performed by configuration component1440. For instance, referring toFIG.8, at806, the base station804configures an ESSB808including SSB810and initial symbol812preceding the SSB. The initial symbol may include a PBCH (e.g. PBCH604as illustrated in the example ofFIG.6), a PSS (e.g. PSS606), or a SSS (e.g. SSS608). The initial symbol may be a repetition of one of the symbols of the SSB (e.g. a repetition of PBCH, PSS, or SSS in SSB402,810). A final symbol of the ESSB may be adjacent to an initial symbol of a second ESSB (e.g. the ESSBs are back-to-back). For instance, as shown in the first example ofFIG.7, final symbol6of one of the ESSBs702for beam1may be adjacent to initial symbol7of another of the ESSBs702for beam2. The ESSB may be transmitted in a pattern associated with a subcarrier spacing greater than 240 kHz (e.g. 960 kHz SCS).

At1204, the base station may transmit an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial transmission of the initial symbol of the ESSB. For example,1204may be performed by indication component1442. For instance, referring toFIG.8, the base station804may transmit the indication814of the number of symbols816of ESSB808, the time domain pattern818of ESSBs, or whether the partial transmission820of ESSB data in initial symbol812is to occur. The indication may be for the base station (e.g. relating to ESSBs from base station804) or another base station (e.g. relating to ESSBs from a neighbor base station). The indication may be transmitted in dedicated signaling (e.g. unicast). The indication may include a quantity (e.g. quantity822) associated with the partial transmission of the initial symbol of the ESSB.

The base station may also transmit, at1204, an SSB indication that the ESSB includes more than four symbols when the base station is a NSA base station. Alternatively, the base station may be a SA base station. For instance, referring toFIG.8, the indication814(or a separate indication) may indicate that ESSB808includes more than four symbols (e.g. initial symbol812and SSB810) when base station804is a NSA base station. Alternatively, base station804may be a SA base station.

At1206, the base station may refrain from transmitting the initial symbol of the ESSB. For example,1206may be performed by symbol component1444. For instance, referring toFIG.8, at824, the base station804may refrain from transmitting the initial symbol812of the ESSB808.

At1208, the base station may switch a transmission beam during a time period for transmitting the initial symbol. For example,1208may be performed by beam component1446. For instance, referring toFIG.8, at824, when the base station804refrains from transmitting the initial symbol812of the ESSB808, the base station may instead use that time period to perform beam switching.

The base station may also switch a transmission beam, at1208, during a time period for transmitting the initial symbol of the ESSB, where the ESSB may be transmitted during a portion of the time period after the switching. For instance, referring toFIG.8, at826, the base station804may switch a transmission beam during a time period for transmitting the initial symbol812of the ESSB808.

Finally, at1210, the base station transmits to a UE at least a portion of the ESSB. For example,1210may be performed by ESSB component1448. For instance, referring toFIG.8, the base station804may transmit ESSB808including SSB810and initial symbol812preceding the SSB. Alternatively, the base station may transmit ESSB808without the initial symbol812(e.g. with only SSB810), or ESSB808with data partially transmitted in initial symbol812.

FIG.13is a diagram1300illustrating an example of a hardware implementation for an apparatus1302. The apparatus1302is a UE and includes a cellular baseband processor1304(also referred to as a modem) coupled to a cellular RF transceiver1322and one or more subscriber identity modules (SIM) cards1320, an application processor1306coupled to a secure digital (SD) card1308and a screen1310, a Bluetooth module1312, a wireless local area network (WLAN) module1314, a Global Positioning System (GPS) module1316, and a power supply1318. The cellular baseband processor1304communicates through the cellular RF transceiver1322with the UE104and/or BS102/180. The cellular baseband processor1304may include a computer-readable medium/memory. The computer-readable medium/memory may be non-transitory. The cellular baseband processor1304is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the cellular baseband processor1304, causes the cellular baseband processor1304to perform the various functions described supra. The computer-readable medium/memory may also be used for storing data that is manipulated by the cellular baseband processor1304when executing software. The cellular baseband processor1304further includes a reception component1330, a communication manager1332, and a transmission component1334. The communication manager1332includes the one or more illustrated components. The components within the communication manager1332may be stored in the computer-readable medium/memory and/or configured as hardware within the cellular baseband processor1304. The cellular baseband processor1304may be a component of the UE350and may include the memory360and/or at least one of the TX processor368, the RX processor356, and the controller/processor359. In one configuration, the apparatus1302may be a modem chip and include just the baseband processor1304, and in another configuration, the apparatus1302may be the entire UE (e.g., see350ofFIG.3) and include the aforediscussed additional modules of the apparatus1302.

The communication manager1332includes an indication component1340that is configured to receive an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial reception of the initial symbol of the ESSB, or to receive an SSB indication that the ESSB includes more than the four symbols when the base station is a non-standalone (NSA) base station, e.g., as described in connection with1002. The communication manager1332further includes an ESSB component1342that is configured to receive, from a base station, an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB, e.g., as described in connection with1004. The communication manager1332further includes a decode component1344that receives input in the form of the ESSB from the ESSB component1342and is configured to refrain from decoding the initial symbol of the ESSB, e.g., as described in connection with1006, or to decode the initial symbol of the ESSB without determining the ESSB includes more than the four symbols, e.g., as described in connection with1012. The communication manager1332further includes a determination component1346that receives input in the form of the ESSB from the ESSB component1342and is configured to determine that the ESSB includes more than the four symbols in response to successfully decoding the ESSB, e.g., as described in connection with1008, to determine that the ESSB includes more than the four symbols in response to detecting a demodulation reference signal (DMRS) in the initial symbol of the ESSB, e.g., as described in connection with1010, or to determine that the ESSB includes more than the four symbols based on channel estimation from a demodulation reference signal (DMRS) in the SSB, e.g., as described in connection with1014. The communication manager1332further includes a beam component1348that receives input in the form of the ESSB from the ESSB component1342and is configured to switch a reception beam during a time period for receiving the initial symbol of the ESSB, e.g., as described in connection with1016, or to maintain a reception beam between a time for receiving the ESSB and a subsequent time for receiving a second ESSB, e.g., as described in connection with1018. The communication manager1332further includes a process component1350that receives input in the form of the ESSB from the ESSB component1342and is configured to process the ESSB, e.g., as described in connection with1020.

The communication manager1332further includes an SSB component1352that is configured to receive a first synchronization signal block (SSB) using a reception beam, e.g., as described in connection with1102. The determination component1346receives input in the form of the first SSB from the SSB component1352and is further configured to determine to maintain the reception beam for a second SSB or to switch the reception beam during a primary synchronization signal (PSS) symbol of the second SSB, e.g., as described in connection with1104. The beam component1348receives input in the form of the first SSB from the SSB component1352and is further configured to switch the reception beam during the PSS symbol, e.g., as described in connection with1106, to maintain the reception beam between the first SSB and the second SSB, e.g., as described in connection with1108, or to switch the reception beam during a gap between the second SSB and a third SSB, e.g., as described in connection with1112. The decode component1344is further configured to refrain from decoding the second SSB, or to refrain from decoding the second SSB during a SSB-based radio resource management (RRM) Measurement Timing Configuration (SMTC) window, e.g., as described in connection with1110.

In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, includes means for receiving, from a base station, an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and means for processing the ESSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for refraining from decoding the initial symbol of the ESSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for determining that the ESSB includes more than the four symbols in response to successfully decoding the ESSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for determining that the ESSB includes more than the four symbols in response to detecting a demodulation reference signal (DMRS) in the initial symbol of the ESSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for decoding the initial symbol of the ESSB without determining the ESSB includes more than the four symbols. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for determining that the ESSB includes more than the four symbols based on channel estimation from a demodulation reference signal (DMRS) in the SSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for switching a reception beam during a time period for receiving the initial symbol of the ESSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for maintaining a reception beam between a time for receiving the ESSB and a subsequent time for receiving a second ESSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for receiving an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial reception of the initial symbol of the ESSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for receiving an SSB indication that the ESSB includes more than the four symbols when the base station is a non-standalone (NSA) base station.

Alternatively, in one configuration, the apparatus1302, and in particular the cellular baseband processor1304, includes means for receiving a first synchronization signal block (SSB) using a reception beam; and means for determining to maintain the reception beam for a second SSB or to switch the reception beam during a primary synchronization signal (PSS) symbol of the second SSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for refraining from decoding the second SSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for switching the reception beam during a gap between the second SSB and a third SSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for switching the reception beam during the PSS symbol. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for maintaining the reception beam between the first SSB and the second SSB. In one configuration, the apparatus1302, and in particular the cellular baseband processor1304, may include means for refraining from decoding the second SSB during a SSB-based radio resource management (RRM) Measurement Timing Configuration (SMTC) window.

The aforementioned means may be one or more of the aforementioned components of the apparatus1302configured to perform the functions recited by the aforementioned means. As described supra, the apparatus1302may include the TX Processor368, the RX Processor356, and the controller/processor359. As such, in one configuration, the aforementioned means may be the TX Processor368, the RX Processor356, and the controller/processor359configured to perform the functions recited by the aforementioned means.

FIG.14is a diagram1400illustrating an example of a hardware implementation for an apparatus1402. The apparatus1402is a BS and includes a baseband unit1404. The baseband unit1404may communicate through a cellular RF transceiver with the UE104. The baseband unit1404may include a computer-readable medium/memory. The baseband unit1404is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the baseband unit1404, causes the baseband unit1404to perform the various functions described supra. The computer-readable medium/memory may also be used for storing data that is manipulated by the baseband unit1404when executing software. The baseband unit1404further includes a reception component1430, a communication manager1432, and a transmission component1434. The communication manager1432includes the one or more illustrated components. The components within the communication manager1432may be stored in the computer-readable medium/memory and/or configured as hardware within the baseband unit1404. The baseband unit1404may be a component of the BS310and may include the memory376and/or at least one of the TX processor316, the RX processor370, and the controller/processor375.

The communication manager1432includes a configuration component1440that configures an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB, e.g., as described in connection with1202. The communication manager1432further includes an indication component1442that transmits an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial transmission of the initial symbol of the ESSB, or that transmits an SSB indication that the ESSB includes more than four symbols when the base station is a non-standalone (NSA) base station, e.g., as described in connection with1204. The communication manager1432further includes a symbol component1444that refrains from transmitting the initial symbol of the ESSB, e.g., as described in connection with1206. The communication manager1432further includes a beam component1446that switches a transmission beam during a time period for transmitting the initial symbol, or that switches a transmission beam during a time period for transmitting the initial symbol of the ESSB, wherein the ESSB is transmitted during a portion of the time period after the switching, e.g., as described in connection with1208. The communication manager1432further includes an ESSB component1448that transmits to a user equipment (UE) at least a portion of the ESSB, e.g., as described in connection with1210.

In one configuration, the apparatus1402, and in particular the baseband unit1404, includes means for configuring an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and means for transmitting to a user equipment (UE) at least a portion of the ESSB. In one configuration, the apparatus1402, and in particular the baseband unit1404, may include means for refraining from transmitting the initial symbol of the ESSB; and means for switching a transmission beam during a time period for transmitting the initial symbol. In one configuration, the apparatus1402, and in particular the baseband unit1404, may include means for switching a transmission beam during a time period for transmitting the initial symbol of the ESSB, wherein the ESSB is transmitted during a portion of the time period after the switching. In one configuration, the apparatus1402, and in particular the baseband unit1404, may include means for transmitting an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial transmission of the initial symbol of the ESSB. In one configuration, the apparatus1402, and in particular the baseband unit1404, may include means for transmitting an SSB indication that the ESSB includes more than four symbols when the base station is a non-standalone (NSA) base station.

The aforementioned means may be one or more of the aforementioned components of the apparatus1402configured to perform the functions recited by the aforementioned means. As described supra, the apparatus1402may include the TX Processor316, the RX Processor370, and the controller/processor375. As such, in one configuration, the aforementioned means may be the TX Processor316, the RX Processor370, and the controller/processor375configured to perform the functions recited by the aforementioned means.

Example 1 is a method of wireless communication at a user equipment (UE), comprising: receiving, from a base station, an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and processing the ESSB.

Example 2 is the method of Example 1, wherein the initial symbol includes a physical broadcast channel (PBCH), a primary synchronization signal (PSS), or a secondary synchronization signal (SSS).

Example 3 is the method of any of Examples 1 and 2, wherein the initial symbol is a repetition of one of the symbols of the SSB.

Example 4 is the method of any of Examples 1 to 3, wherein a final symbol of the ESSB is adjacent to an initial symbol of a second ESSB.

Example 5 is the method of any of Examples 1 to 4, wherein the ESSB is received in a pattern associated with a subcarrier spacing greater than 240 kHz.

Example 6 is the method of any of Examples 1 to 5, further comprising refraining from decoding the initial symbol of the ESSB.

Example 7 is the method of any of Examples 1 to 5, further comprising determining that the ESSB includes more than the four symbols in response to successfully decoding the ESSB.

Example 8 is the method of any of Examples 1 to 5, further comprising determining that the ESSB includes more than the four symbols in response to detecting a demodulation reference signal (DMRS) in the initial symbol of the ESSB.

Example 9 is the method of any of Examples 1 to 5, further comprising decoding the initial symbol of the ESSB without determining the ESSB includes more than the four symbols.

Example 10 is the method of any of Examples 1 to 5, further comprising determining that the ESSB includes more than the four symbols based on channel estimation from a demodulation reference signal (DMRS) in the SSB.

Example 11 is the method of any of Examples 1 to 10, further comprising switching a reception beam during a time period for receiving the initial symbol of the ESSB.

Example 12 is the method of any of Examples 1 to 10, further comprising maintaining a reception beam between a time for receiving the ESSB and a subsequent time for receiving a second ESSB.

Example 13 is the method of any of Examples 1 to 12, further comprising receiving an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial reception of the initial symbol of the ESSB.

Example 14 is the method of Example 13, wherein the indication is for the base station or another base station.

Example 15 is the method of Example 13 or 14, wherein the indication is received in dedicated signaling.

Example 16 is the method of any of Examples 13 to 15, wherein the indication includes a quantity associated with the partial reception of the initial symbol of the ESSB.

Example 17 is the method of any of Examples 1 to 16, wherein the base station is a standalone (SA) base station.

Example 18 is the method of any of Examples 1 to 16, further comprising receiving an SSB indication that the ESSB includes more than the four symbols when the base station is a non-standalone (NSA) base station.

Example 19 is an apparatus for wireless communication, comprising: a processor; memory coupled with the processor; and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to: receive, from a base station, an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and process the ESSB.

Example 20 is the apparatus of Example 19, wherein the initial symbol includes a physical broadcast channel (PBCH), a primary synchronization signal (PSS), or a secondary synchronization signal (SSS).

Example 21 is the apparatus of Example 19 or 20, wherein the initial symbol is a repetition of one of the symbols of the SSB.

Example 22 is the apparatus of any of Examples 19 to 21, wherein a final symbol of the ESSB is adjacent to an initial symbol of a second ESSB.

Example 23 is the apparatus of any of Examples 19 to 22, wherein the ESSB is received in a pattern associated with a subcarrier spacing greater than 240 kHz.

Example 24 is the apparatus of any of Examples 19 to 23, wherein the instructions, when executed by the processor, further cause the apparatus to refrain from decoding the initial symbol of the ESSB.

Example 25 is the apparatus of any of Examples 19 to 23, wherein the instructions, when executed by the processor, further cause the apparatus to determine that the ESSB includes more than the four symbols in response to successfully decoding the ESSB.

Example 26 is the apparatus of any of Examples 19 to 23, wherein the instructions, when executed by the processor, further cause the apparatus to determine that the ESSB includes more than the four symbols in response to detecting a demodulation reference signal (DMRS) in the initial symbol of the ESSB.

Example 27 is the apparatus of any of Examples 19 to 23, wherein the instructions, when executed by the processor, further cause the apparatus to decode the initial symbol of the ESSB without determining the ESSB includes more than the four symbols.

Example 28 is the apparatus of any of Examples 19 to 23, wherein the instructions, when executed by the processor, further cause the apparatus to determine that the ESSB includes more than the four symbols based on channel estimation from a demodulation reference signal (DMRS) in the SSB.

Example 29 is the apparatus of any of Examples 19 to 28, wherein the instructions, when executed by the processor, further cause the apparatus to switch a reception beam during a time period for receiving the initial symbol of the ESSB.

Example 30 is the apparatus of any of Examples 19 to 28, wherein the instructions, when executed by the processor, further cause the apparatus to maintain a reception beam between a time for receiving the ESSB and a subsequent time for receiving a second ESSB.

Example 31 is the apparatus of any of Examples 19 to 30, wherein the instructions, when executed by the processor, further cause the apparatus to receive an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial reception of the initial symbol of the ESSB.

Example 32 is the apparatus of Example 31, wherein the indication is for the base station or another base station.

Example 33 is the apparatus of Example 31 or 32, wherein the indication is received in dedicated signaling.

Example 34 is the apparatus of any of Examples 31 to 33, wherein the indication includes a quantity associated with the partial reception of the initial symbol of the ESSB.

Example 35 is the apparatus of any of Examples 19 to 34, wherein the base station is a standalone (SA) base station.

Example 36 is the apparatus of any of Examples 19 to 34, wherein the instructions, when executed by the processor, further cause the apparatus to receive an SSB indication that the ESSB includes more than the four symbols when the base station is a non-standalone (NSA) base station.

Example 37 is an apparatus for wireless communication, comprising: means for receiving, from a base station, an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and means for processing the ESSB.

Example 38 is the apparatus of Example 37, wherein the initial symbol includes a physical broadcast channel (PBCH), a primary synchronization signal (PSS), or a secondary synchronization signal (SSS).

Example 39 is the apparatus of Example 37 or 38, wherein the initial symbol is a repetition of one of the symbols of the SSB.

Example 40 is the apparatus of any of Examples 37 to 39, wherein a final symbol of the ESSB is adjacent to an initial symbol of a second ESSB.

Example 41 is the apparatus of any of Examples 37 to 40, wherein the ESSB is received in a pattern associated with a subcarrier spacing greater than 240 kHz.

Example 42 is the apparatus of any of Examples 37 to 41, further comprising means for refraining from decoding the initial symbol of the ESSB.

Example 43 is the apparatus of any of Examples 37 to 41, further comprising means for determining that the ESSB includes more than the four symbols in response to successfully decoding the ESSB.

Example 44 is the apparatus of any of Examples 37 to 41, further comprising means for determining that the ESSB includes more than the four symbols in response to detecting a demodulation reference signal (DMRS) in the initial symbol of the ESSB.

Example 45 is the apparatus of any of Examples 37 to 41, further comprising means for decoding the initial symbol of the ESSB without determining the ESSB includes more than the four symbols.

Example 46 is the apparatus of any of Examples 37 to 41, further comprising means for determining that the ESSB includes more than the four symbols based on channel estimation from a demodulation reference signal (DMRS) in the SSB.

Example 47 is the apparatus of any of Examples 37 to 46, further comprising means for switching a reception beam during a time period for receiving the initial symbol of the ESSB.

Example 48 is the apparatus of any of Examples 37 to 46, further comprising means for maintaining a reception beam between a time for receiving the ESSB and a subsequent time for receiving a second ESSB.

Example 49 is the apparatus of any of Examples 37 to 48, further comprising means for receiving an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial reception of the initial symbol of the ESSB.

Example 50 is the apparatus of Example 49, wherein the indication is for the base station or another base station.

Example 51 is the apparatus of Example 49 or 50, wherein the indication is received in dedicated signaling.

Example 52 is the apparatus of any of Examples 49 to 51, wherein the indication includes a quantity associated with the partial reception of the initial symbol of the ESSB.

Example 53 is the apparatus of any of Examples 37 to 52, wherein the base station is a standalone (SA) base station.

Example 54 is the apparatus of any of Examples 37 to 52, further comprising means for receiving an SSB indication that the ESSB includes more than the four symbols when the base station is a non-standalone (NSA) base station.

Example 55 is a computer-readable medium storing computer executable code, the code when executed by a processor cause the processor to: receive, from a base station, an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and process the ESSB.

Example 56 is a method of wireless communication at a user equipment (UE), comprising: receiving a first synchronization signal block (SSB) using a reception beam; and determining to maintain the reception beam for a second SSB or to switch the reception beam during a primary synchronization signal (PSS) symbol of the second SSB.

Example 57 is the method of Example 56, further comprising refraining from decoding the second SSB.

Example 58 is the method of Examples 56 or 57, further comprising switching the reception beam during a gap between the second SSB and a third SSB.

Example 59 is the method of any of Examples 56 to 58, further comprising switching the reception beam during the PSS symbol.

Example 60 is the method of any of Examples 56 to 58, further comprising maintaining the reception beam between the first SSB and the second SSB.

Example 61 is the method of any of Examples 56 to 60, further comprising refraining from decoding the second SSB during a SSB-based radio resource management (RRM) Measurement Timing Configuration (SMTC) window.

Example 62 is an apparatus for wireless communication, comprising: a processor; memory coupled with the processor; and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to: receive a first synchronization signal block (SSB) using a reception beam; and determine to maintain the reception beam for a second SSB or to switch the reception beam during a primary synchronization signal (PSS) symbol of the second SSB.

Example 63 is the apparatus of Example 62, wherein the instructions, when executed by the processor, further cause the apparatus to refrain from decoding the second SSB.

Example 64 is the apparatus of Example 62 or 63, wherein the instructions, when executed by the processor, further cause the apparatus to switch the reception beam during a gap between the second SSB and a third SSB.

Example 65 is the apparatus of any of Examples 62 to 64, wherein the instructions, when executed by the processor, further cause the apparatus to switch the reception beam during the PSS symbol.

Example 66 is the apparatus of any of Examples 62 to 64, wherein the instructions, when executed by the processor, further cause the apparatus to maintain the reception beam between the first SSB and the second SSB.

Example 67 is the apparatus of any of Examples 62 to 66, wherein the instructions, when executed by the processor, further cause the apparatus to refrain from decoding the second SSB during a SSB-based radio resource management (RRM) Measurement Timing Configuration (SMTC) window.

Example 68 is an apparatus for wireless communication, comprising: means for receiving a first synchronization signal block (SSB) using a reception beam; and means for determining to maintain the reception beam for a second SSB or to switch the reception beam during a primary synchronization signal (PSS) symbol of the second SSB.

Example 69 is the apparatus of Example 68, further comprising means for refraining from decoding the second SSB.

Example 70 is the apparatus of Example 68 or 69, further comprising means for switching the reception beam during a gap between the second SSB and a third SSB.

Example 71 is the apparatus of any of Examples 68 to 70, further comprising means for switching the reception beam during the PSS symbol.

Example 72 is the apparatus of any of Examples 68 to 70, further comprising means for maintaining the reception beam between the first SSB and the second SSB.

Example 73 is the apparatus of any of Examples 68 to 72, further comprising means for refraining from decoding the second SSB during a SSB-based radio resource management (RRM) Measurement Timing Configuration (SMTC) window.

Example 74 is a computer-readable medium storing computer executable code, the code when executed by a processor cause the processor to: receive a first synchronization signal block (SSB) using a reception beam; and determine to maintain the reception beam for a second SSB or to switch the reception beam during a primary synchronization signal (PSS) symbol of the second SSB.

Example 75 is a method of wireless communication at a base station, comprising: configuring an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and transmitting to a user equipment (UE) at least a portion of the ESSB.

Example 76 is the method of Example 75, wherein the initial symbol includes a physical broadcast channel (PBCH), a primary synchronization signal (PSS), or a secondary synchronization signal (SSS).

Example 77 is the method of Example 75 or 76, wherein the initial symbol is a repetition of one of the symbols of the SSB.

Example 78 is the method of any of Examples 75 to 77, wherein a final symbol of the ESSB is adjacent to an initial symbol of a second ESSB.

Example 79 is the method of any of Examples 75 to 78, wherein the ESSB is transmitted in a pattern associated with a subcarrier spacing greater than 240 kHz.

Example 80 is the method of any of Examples 75 to 79, further comprising: refraining from transmitting the initial symbol of the ESSB; and switching a transmission beam during a time period for transmitting the initial symbol.

Example 81 is the method of any of Examples 75 to 79, further comprising switching a transmission beam during a time period for transmitting the initial symbol of the ESSB, wherein the ESSB is transmitted during a portion of the time period after the switching.

Example 82 is the method of any of Examples 75 to 81, further comprising transmitting an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial transmission of the initial symbol of the ESSB.

Example 83 is the method of Example 82, wherein the indication is for the base station or another base station.

Example 84 is the method of Example 82 or 83, wherein the indication is transmitted in dedicated signaling.

Example 85 is the method of any of Examples 82 to 84, wherein the indication includes a quantity associated with the partial transmission of the initial symbol of the ESSB.

Example 86 is the method of any of Examples 75 to 85, wherein the base station is a standalone (SA) base station.

Example 87 is the method of any of Examples 75 to 85, further comprising transmitting an SSB indication that the ESSB includes more than four symbols when the base station is a non-standalone (NSA) base station.

Example 88 is an apparatus for wireless communication, comprising: a processor; memory coupled with the processor; and instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to: configure an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and transmit to a user equipment (UE) at least a portion of the ESSB.

Example 89 is the apparatus of Example 88, wherein the initial symbol includes a physical broadcast channel (PBCH), a primary synchronization signal (PSS), or a secondary synchronization signal (SSS).

Example 90 is the apparatus of Example 88 or 89, wherein the initial symbol is a repetition of one of the symbols of the SSB.

Example 91 is the apparatus of any of Examples 88 to 90, wherein a final symbol of the ESSB is adjacent to an initial symbol of a second ESSB.

Example 92 is the apparatus of any of Examples 88 to 91, wherein the ESSB is transmitted in a pattern associated with a subcarrier spacing greater than 240 kHz.

Example 93 is the apparatus of any of Examples 88 to 92, wherein the instructions, when executed by the processor, further cause the apparatus to: refrain from transmitting the initial symbol of the ESSB; and switch a transmission beam during a time period for transmitting the initial symbol.

Example 94 is the apparatus of any of Examples 88 to 92, wherein the instructions, when executed by the processor, further cause the apparatus to switch a transmission beam during a time period for transmitting the initial symbol of the ESSB, wherein the ESSB is transmitted during a portion of the time period after the switching.

Example 95 is the apparatus of any of Examples 88 to 94, wherein the instructions, when executed by the processor, further cause the apparatus to transmit an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial transmission of the initial symbol of the ESSB.

Example 96 is the apparatus of Example 95, wherein the indication is for the apparatus or another base station.

Example 97 is the apparatus of Examples 95 or 96, wherein the indication is transmitted in dedicated signaling.

Example 98 is the apparatus of any of Examples 95 to 97, wherein the indication includes a quantity associated with the partial transmission of the initial symbol of the ESSB.

Example 99 is the apparatus of any of Examples 88 to 98, wherein the apparatus is a standalone (SA) base station.

Example 100 is the apparatus of any of Examples 88 to 98, wherein the instructions, when executed by the processor, further cause the apparatus to transmit an SSB indication that the ESSB includes more than four symbols when the apparatus is a non-standalone (NSA) base station.

Example 101 is an apparatus for wireless communication, comprising: means for configuring an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and means for transmitting to a user equipment (UE) at least a portion of the ESSB.

Example 102 is the apparatus of Example 101, wherein the initial symbol includes a physical broadcast channel (PBCH), a primary synchronization signal (PSS), or a secondary synchronization signal (SSS).

Example 103 is the apparatus of Example 101 or 102, wherein the initial symbol is a repetition of one of the symbols of the SSB.

Example 104 is the apparatus of any of Examples 101 to 103, wherein a final symbol of the ESSB is adjacent to an initial symbol of a second ESSB.

Example 105 is the apparatus of any of Examples 101 to 104, wherein the ESSB is transmitted in a pattern associated with a subcarrier spacing greater than 240 kHz.

Example 106 is the apparatus of any of Examples 101 to 105, further comprising: means for refraining from transmitting the initial symbol of the ESSB; and means for switching a transmission beam during a time period for transmitting the initial symbol.

Example 107 is the apparatus of any of Examples 101 to 105, further comprising means for switching a transmission beam during a time period for transmitting the initial symbol of the ESSB, wherein the ESSB is transmitted during a portion of the time period after the switching.

Example 108 is the apparatus of any of Examples 101 to 107, further comprising means for transmitting an indication of a number of the symbols of the ESSB, a time domain pattern of ESSBs, or a partial transmission of the initial symbol of the ESSB.

Example 109 is the apparatus of Example 108, wherein the indication is for the apparatus or another base station.

Example 110 is the apparatus of Example 108 or 109, wherein the indication is transmitted in dedicated signaling.

Example 111 is the apparatus of any of Examples 108 to 110, wherein the indication includes a quantity associated with the partial transmission of the initial symbol of the ESSB.

Example 112 is the apparatus of any of Examples 101 to 111, wherein the apparatus is a standalone (SA) base station.

Example 113 is the apparatus of any of Examples 101 to 111, further comprising means for transmitting an SSB indication that the ESSB includes more than four symbols when the apparatus is a non-standalone (NSA) base station.

Example 114 is a computer-readable medium storing computer executable code, the code when executed by a processor cause the processor to: configure an extended synchronization signal block (ESSB), wherein the ESSB comprises a synchronization signal block (SSB) including four symbols and an initial symbol preceding the SSB; and transmit to a user equipment (UE) at least a portion of the ESSB.