Carrier information signaling in a 5G network

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may receive carrier information identifying at least one of: an initial absolute frequency for a carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency; and determine a resource allocation of the carrier based at least in part on the carrier information and a subcarrier spacing of the user equipment. Numerous other aspects are provided.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication, and more particularly to techniques and apparatuses for carrier information signaling in a 5G network.

BACKGROUND

SUMMARY

In some aspects, a method of wireless communication, performed by a user equipment, may include receiving carrier information identifying at least one of: an initial absolute frequency for a carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency; and determining a configuration of the carrier based at least in part on the carrier information and a subcarrier spacing of the user equipment.

In some aspects, a user equipment for wireless communication may include memory and at least one processor operatively coupled to the memory. The memory and the at least one processor may be configured to receive carrier information identifying at least one of: an initial absolute frequency for a carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency; and determine a configuration of the carrier based at least in part on the carrier information and a subcarrier spacing of the user equipment.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a user equipment, may cause the one or more processors to receive carrier information identifying at least one of: an initial absolute frequency for a carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency; and determine a configuration of the carrier based at least in part on the carrier information and a subcarrier spacing of the user equipment.

In some aspects, an apparatus for wireless communication may include means for receiving carrier information identifying at least one of: an initial absolute frequency for a carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency; and means for determining a configuration of the carrier based at least in part on the carrier information and a subcarrier spacing of the apparatus.

In some aspects, a method of wireless communication performed by a base station may include determining a configuration of a carrier for a user equipment (UE) based at least in part on a subcarrier spacing of the UE; and transmitting carrier information identifying the configuration, wherein the carrier information includes at least one of: an initial absolute frequency for the carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency.

In some aspects, a base station for wireless communication may include memory and at least one processor operatively coupled to the memory. The memory and the at least one processor may be configured to determine a configuration of a carrier for a user equipment (UE) based at least in part on a subcarrier spacing of the UE; and transmit carrier information identifying the configuration, wherein the carrier information includes at least one of: an initial absolute frequency for the carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a base station, may cause the one or more processors to determine a configuration of a carrier for a user equipment (UE) based at least in part on a subcarrier spacing of the UE; and transmit carrier information identifying the configuration, wherein the carrier information includes at least one of: an initial absolute frequency for the carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency.

In some aspects, an apparatus for wireless communication may include means for determining a configuration of a carrier for a user equipment (UE) based at least in part on a subcarrier spacing of the UE; and means for transmitting carrier information identifying the configuration, wherein the carrier information includes at least one of: an initial absolute frequency for the carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency.

DETAILED DESCRIPTION

FIG. 2shows a block diagram of a design of BS110and UE120, which may be one of the base stations and one of the UEs inFIG. 1. BS110may be equipped with T antennas234athrough234t, and UE120may be equipped with R antennas252athrough252r, where in general T≥1 and R≥1.

In some aspects, one or more components of UE120may be included in a housing. Controller/processor240of BS110, controller/processor280of UE120, and/or any other component(s) ofFIG. 2may perform one or more techniques associated with carrier information signaling in a 5G network, as described in more detail elsewhere herein. For example, controller/processor240of BS110, controller/processor280of UE120, and/or any other component(s) ofFIG. 2may perform or direct operations of, for example, process700ofFIG. 7, process800ofFIG. 8, and/or other processes as described herein. Memories242and282may store data and program codes for BS110and UE120, respectively. A scheduler246may schedule UEs for data transmission on the downlink and/or uplink.

In some aspects, UE120may include means for receiving carrier information; means for determining a resource allocation of the carrier based at least in part on the carrier information and a subcarrier spacing; means for determining, based at least in part on the reference frequency, at least one of: a pseudo-noise sequence for the carrier, a resource block group for the carrier, a precoder resource block granularity for the carrier, or a location of a sounding reference signal for the carrier; means for determining a bandwidth part based at least in part on the carrier information and based at least in part on information identifying at least one of a starting resource block of the bandwidth part or an ending resource block of the bandwidth part; means for receiving uplink carrier information for an uplink carrier; means for determining a resource allocation of the uplink carrier based at least in part on the uplink carrier information; and/or the like. In some aspects, such means may include one or more components of UE120described in connection withFIG. 2.

In some aspects, BS110may include means for determining a resource allocation of a carrier for a UE based at least in part on a subcarrier spacing of the UE; means for transmitting carrier information identifying the resource allocation; means for transmitting information identifying at least one of a starting resource block of a bandwidth part or an ending resource block of the bandwidth part, wherein the carrier information is for the bandwidth part; means for transmitting uplink carrier information for an uplink carrier; and/or the like. In some aspects, such means may include one or more components of BS110described in connection withFIG. 2.

As indicated above,FIG. 2is provided merely as an example. Other examples are possible and may differ from what was described with regard toFIG. 2.

FIG. 3Ashows an example frame structure300for frequency division duplexing (FDD) in a telecommunications system (e.g., NR). The transmission timeline for each of the downlink and uplink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration and may be partitions into a set of Z (Z≥1) subframes (e.g., with indices of 0 through Z−1). Each subframe may include a set of slots (e.g., two slots per subframe are shown inFIG. 3A). Each slot may include a set of L symbol periods. For example, each slot may include seven symbol periods (e.g., as shown inFIG. 3A), fifteen symbol periods, and/or the like. In a case where the subframe includes two slots, the subframe may include 2L symbol periods, where the 2L symbol periods in each subframe may be assigned indices of 0 through 2L−1. In some aspects, a scheduling unit for the FDD may frame-based, subframe-based, slot-based, symbol-based, and/or the like.

In certain telecommunications (e.g., NR), a base station may transmit synchronization signals. For example, a base station may transmit a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and/or the like, on the downlink for each cell supported by the base station. The PSS and SSS may be used by UEs for cell search and acquisition. For example, the PSS may be used by UEs to determine symbol timing, and the SSS may be used by UEs to determine a physical cell identifier, associated with the base station, and frame timing. The base station may also transmit a physical broadcast channel (PBCH). The PBCH may carry some system information, such as system information that supports initial access by UEs.

In some aspects, the base station may transmit the PSS, the SSS, and/or the PBCH in accordance with a synchronization communication hierarchy (e.g., a synchronization signal (SS) hierarchy) including multiple synchronization communications (e.g., SS blocks), as described below in connection withFIG. 3B.

FIG. 3Bis a block diagram conceptually illustrating an example SS hierarchy, which is an example of a synchronization communication hierarchy. As shown inFIG. 3B, the SS hierarchy may include an SS burst set, which may include a plurality of SS bursts (identified as SS burst 0 through SS burst B−1, where B is a maximum number of repetitions of the SS burst that may be transmitted by the base station). As further shown, each SS burst may include one or more SS blocks (identified as SS block 0 through SS block (bmax_SS-1), where bmax_SS-1is a maximum number of SS blocks that can be carried by an SS burst). In some aspects, different SS blocks may be beam-formed differently. An SS burst set may be periodically transmitted by a wireless node, such as every X milliseconds, as shown inFIG. 3B. In some aspects, an SS burst set may have a fixed or dynamic length, shown as Y milliseconds inFIG. 3B.

The SS burst set shown inFIG. 3Bis an example of a synchronization communication set, and other synchronization communication sets may be used in connection with the techniques described herein. Furthermore, the SS block shown inFIG. 3Bis an example of a synchronization communication, and other synchronization communications may be used in connection with the techniques described herein.

In some aspects, an SS block includes resources that carry the PSS, the SSS, the PBCH, and/or other synchronization signals (e.g., a tertiary synchronization signal (TSS)) and/or synchronization channels. In some aspects, multiple SS blocks are included in an SS burst, and the PSS, the SSS, and/or the PBCH may be the same across each SS block of the SS burst. In some aspects, a single SS block may be included in an SS burst. In some aspects, the SS block may be at least four symbol periods in length, where each symbol carries one or more of the PSS (e.g., occupying one symbol), the SSS (e.g., occupying one symbol), and/or the PBCH (e.g., occupying two symbols).

In some aspects, the symbols of an SS block are consecutive, as shown inFIG. 3B. In some aspects, the symbols of an SS block are non-consecutive. Similarly, in some aspects, one or more SS blocks of the SS burst may be transmitted in consecutive radio resources (e.g., consecutive symbol periods) during one or more subframes. Additionally, or alternatively, one or more SS blocks of the SS burst may be transmitted in non-consecutive radio resources.

In some aspects, the SS bursts may have a burst period, whereby the SS blocks of the SS burst are transmitted by the base station according to the burst period. In other words, the SS blocks may be repeated during each SS burst. In some aspects, the SS burst set may have a burst set periodicity, whereby the SS bursts of the SS burst set are transmitted by the base station according to the fixed burst set periodicity. In other words, the SS bursts may be repeated during each SS burst set.

The base station may transmit system information, such as system information blocks (SIBs) on a physical downlink shared channel (PDSCH) in certain subframes. The base station may transmit control information/data on a physical downlink control channel (PDCCH) in C symbol periods of a subframe, where B may be configurable for each subframe. The base station may transmit traffic data and/or other data on the PDSCH in the remaining symbol periods of each subframe.

As indicated above,FIGS. 3A and 3Bare provided as examples. Other examples are possible and may differ from what was described with regard toFIGS. 3A and 3B.

FIG. 4shows an example subframe format410with a normal cyclic prefix. The available time frequency resources may be partitioned into resource blocks. Each resource block may cover a set to of subcarriers (e.g., 12 subcarriers) in one slot and may include a number of resource elements. Each resource element may cover one subcarrier in one symbol period (e.g., in time) and may be used to send one modulation symbol, which may be a real or complex value. In some aspects, subframe format410may be used for transmission of SS blocks that carry the PSS, the SSS, the PBCH, and/or the like, as described herein.

A UE may be located within the coverage of multiple BSs. One of these BSs may be selected to serve the UE. The serving BS may be selected based at least in part on various criteria such as received signal strength, received signal quality, path loss, and/or the like. Received signal quality may be quantified by a signal-to-noise-and-interference ratio (SINR), or a reference signal received quality (RSRQ), or some other metric. The UE may operate in a dominant interference scenario in which the UE may observe high interference from one or more interfering BSs.

In some aspects, a single component carrier bandwidth of 100 MHZ may be supported. NR resource blocks may span 12 sub-carriers with a sub-carrier bandwidth of 60 or 120 kilohertz (kHz) over a 0.1 millisecond (ms) duration. Each radio frame may include 40 subframes with a length of 10 ms. Consequently, each subframe may have a length of 0.25 ms. Each subframe may indicate a link direction (e.g., DL or UL) for data transmission and the link direction for each subframe may be dynamically switched. Each subframe may include DL/UL data as well as DL/UL control data.

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

In 5G (e.g., NR), a BS (e.g., BS110) may configure a carrier (e.g., a component carrier, a DL carrier, an UL carrier) and/or a bandwidth part (BWP) of a carrier for a UE (e.g., UE120). 5G may provide increased flexibility in configuring the carrier relative to some other radio access technologies (RATs). For example, the UE may be capable of using a flexible bandwidth allocation, and a carrier and/or BWP for the UE may be assigned based at least in part on demand for bandwidth, traffic considerations, and/or the like. Also, different UEs may use different subcarrier spacings (e.g., numerologies, tone spacings, etc.), which may lead to increased flexibility in configuration of carriers and/or BWPs.

A resource allocation for a carrier or BWP may be defined by various parameters, which are described in more detail in connection withFIG. 5, below. However, it may be inefficient for a BS to signal all of the various parameters to a UE, particularly since many of the parameters are interrelated. For example, a UE may need only a subset of the parameters to determine the resource allocation for a particular carrier or BWP.

Some techniques and apparatuses described herein provide signaling of carrier information identifying parameters for a configuration of a carrier for a UE. For example, the carrier information may include a subset of possible parameters (e.g., not all possible parameters) regarding the carrier. The UE may use the carrier information to determine the configuration. In this way, a subset of possible parameters are provided to a UE for determination of a configuration for a carrier of the UE, thereby conserving UE, BS, and network resources that would otherwise be used to provide a larger set of parameters.

FIG. 5is a diagram illustrating an example500of carriers having odd numbers of RBs and even numbers of RBs for a 5G UE (e.g., UE120), in accordance with various aspects of the present disclosure. InFIG. 5, carriers502,504,506, and508are described, and are shown inFIG. 5using shaded blocks. InFIG. 5, μ represents a subcarrier spacing, tone spacing, or numerology of a corresponding carrier, and may have a value of M, M+1, and/or the like. M is an integer. A single increment of M may correspond to a two-fold increase in μ. For example, M=0 may correspond to a subcarrier spacing of 15 kHz, M=1 may correspond to a subcarrier spacing of 30 kHz, and so on. As can be seen, carriers502and506are associated with μ=M+1, and carriers504and508are associated with μ=M. In some aspects, carriers502through508may be component carriers. Additionally, or alternatively, carriers502through508may be bandwidth parts.

As shown by reference number510, carriers502through508may be associated with a reference frequency. The reference frequency may be identified by a synchronization signal block (SS block or SSB) received by the UE. For example, the reference frequency may be identified by a physical broadcast channel of the SSB. In some aspects, a location of the reference frequency may be defined by the product of an integer and a subcarrier spacing value (e.g., 15 kHz for sub-6 GHz or 60 kHz for mm Wave), in relation to a channel raster point. For example, the reference frequency location may be defined as 4*15 kHz from a channel raster point in a sub-6 GHz system. The reference frequency location may be identical for different subcarrier spacings. For example, as can be seen, carriers associated with μ=M may have a same reference frequency location as carriers associated with μ=M+1.

As shown inFIG. 5, and by reference number512, carrier502may be associated with a carrier center frequency. For example, the carrier center frequency may be located at a center of carrier502, shown here as resource element (RE) number6of a center resource block of carrier502. As shown by reference number514, carrier504may be associated with a carrier center frequency that is different than the carrier center frequency of carrier502, shown here as RE number6of a center resource block of carrier504. This may be because carrier504has a wider bandwidth than carrier502.

The left edges of carriers502through508, as shown inFIG. 5, may correspond to a lowest frequency (e.g., a lowest resource element (RE) of a lowest resource block (RB)) of the carriers. In some aspects, the left edges may be referred to as a channel start or a channel edge. The right edges of carriers502through508, as shown inFIG. 5, may correspond to a highest frequency (e.g., a highest resource element (RE) of a highest resource block (RB)) of the carriers. In some aspects, the right edges may be referred to as a channel end or a channel edge. As can be seen, in some aspects, a channel start and/or a channel end may be different for different values of μ. In some aspects, a channel start and/or channel end may be located on a valid channel raster point. A channel raster may identify a frequency grid for channels of a band. In some aspects, a channel start and/or a channel end may be located on a point defined by the channel raster. For example, in a 15 kHz subcarrier spacing, the channel raster may define points every 15 kHz offset from a particular starting frequency, which may be equal to the reference frequency described in connection with reference number510.

As shown by reference number516, carrier504(and the other carriers502,506,508) may be associated with a frequency offset from the reference frequency. In some aspects, the frequency offset may be measured between the reference frequency location and a channel start of a carrier. In some aspects, the frequency offset may be defined as an integer number of RBs. In some aspects, the frequency offset may be different for different subcarrier spacings. For example, for carrier502, the frequency offset may be 3 RBs, and for carrier504, the frequency offset may be 6 RBs.

In some aspects, the reference frequency location may be further away from the channel edge than a maximum supported channel bandwidth. For example, assume that the UE has a maximum supported channel bandwidth of 40 MHz, and assume that the carrier of the UE is a 40 MHz carrier. In such a case, the reference frequency used to identify the carrier may be located more than 40 MHz away from a channel edge of the carrier. This may provide forward compatibility for larger bandwidths than 40 MHz.

As shown by reference number518, a carrier may be associated with a value indicating a tone offset from the DC of the carrier to the RB boundary, which may be referred to herein as a tone boundary offset value, denoted by k0. The tone boundary offset value may be equal to a number of tones (e.g., REs) between a center of a component carrier and an edge of the RB. In other words, the tone boundary offset value may identify a direct current (DC) offset from an RB boundary of the UE in the corresponding carrier. For example, for carriers502and504, the tone boundary offset value is equal to 6. Note that the tone boundary offset value is not necessarily an offset from the center of one carrier to the center of the other—the arrow for the tone boundary offset value is situated between the center lines of the carriers coincidentally inFIG. 5. The UE may use the tone boundary offset value to identify edges of RBs in a case wherein the tone boundary of an RB is offset from a DC subcarrier.

In some aspects, a carrier may include a particular number of RBs. For example, carrier502includes 5 RBs and carrier504includes 11 RBs. The number of RBs may be determined by a scheduling entity. In some aspects, the number of RBs may not be exactly proportionate to the subcarrier spacing. For example, the number of RBs may not necessarily be doubled when comparing μ=M and μ=M+1.

In some aspects, a carrier may be associated with a channel number. A channel number may point to a frequency corresponding to k+k0, as defined in 3GPP Technical Specification 38.211. The channel number may point to a valid channel raster point. In some aspects, the channel number may not correspond to a midpoint of the channel for every subcarrier spacing. In some aspects, the channel number may be equal for different subcarrier spacings. In some aspects, a channel number may be used when switching from one RAT to another RAT (e.g., in a non-standalone deployment).

Some of the parameters described above may be dependent on each other, and some of the parameters described above may be independent from each other. For example, the channel number of a carrier may be independent from a subcarrier spacing of the carrier. In some aspects, the k0of a carrier may be related to the subcarrier spacing of the carrier. In some aspects, the number of RBs of a carrier may be related to the subcarrier spacing of the carrier. Additionally, or alternatively, the frequency offset of a carrier may be a function of the subcarrier spacing of the carrier. Techniques and apparatuses described herein provide a subset of the parameters (e.g., a subset of frequency offset, channel start, channel end, channel center, channel number, k0, number of RBs, and reference frequency location) to enable the UE to determine a resource allocation of a carrier (e.g., using relationships between the parameters that are provided and parameters that are not provided). In this way, resources are conserved in comparison to providing an entirety of the parameters for a carrier.

Carriers502through508each include an odd number of RBs. In some aspects, a carrier may include an even number of RBs. In such a case, a k0value of the carrier may be equal to 0, since no phase boundary offset is present in a carrier with an even number of RBs.

As indicated above,FIG. 5is provided as an example. Other examples are possible and may differ from what was described with respect toFIG. 5.

FIG. 6is a diagram illustrating an example600of carrier information signaling in a 5G network, in accordance with various aspects of the present disclosure.

As shown inFIG. 6, and by reference number610, a BS110may determine a configuration of a carrier for a UE120. In some aspects, the configuration may be referred to herein as a resource allocation. For example, the BS110may determine a bandwidth of the carrier (e.g., a number of RBs and/or the like), a frequency location of the carrier (e.g., based at least in part on spectral utilization), and/or the like. The BS110may determine the configuration based at least in part on a subcarrier spacing of the UE120. For example, the UE120may be associated with a particular subcarrier spacing, and the BS110may determine the configuration based at least in part on the particular subcarrier spacing.

As shown by reference number620, the BS110may provide carrier information to the UE120. The carrier information may be used by the UE120to identify the configuration. Here, the carrier information includes one or more parameters, such as a channel number, a tone boundary offset value (e.g., k0), a number of resource blocks, and a frequency offset from a reference frequency. For example, the channel number may include an identifier of a physical channel, such as an index value corresponding to the physical channel. The tone boundary offset value may identify a tone boundary offset of the carrier. The number of resource blocks may identify a number of resource blocks included in the carrier. The frequency offset may identify an offset (e.g., in terms of a number of RBs) from a reference frequency to the carrier (e.g., to a channel start of the carrier). In some aspects, the carrier information may include all of the above-identified parameters. In some aspects, the carrier information may include a subset of the above-identified parameters (i.e., fewer than all of the above-identified parameters), such as the tone boundary offset value, the number of resource blocks, and the frequency offset. In some aspects, the carrier information may include one or more of the above-identified parameters in a particular case. For example, in the case when a UE is to be handed over from one RAT to another, the carrier information may include the channel number. In some aspects, the carrier information may include one or more parameters that are different from the above-identified parameters.

As shown by reference number630, the UE120may determine the configuration of the carrier using the carrier information. For example, the UE120may know the subcarrier spacing (e.g., based at least in part on configuration of the UE120) and the reference frequency (e.g., based at least in part on a synchronization signal block or PBCH received by the UE120). The UE120may determine the configuration of the carrier using the carrier information. Various examples of determination of the configuration of the carrier are provided below.

In some aspects, the UE120may use the subcarrier spacing, the reference frequency, and the frequency offset to identify a location of a channel start of the carrier. For example, the UE120may offset a number of RBs, with a bandwidth determined according to the subcarrier spacing, from the reference frequency to determine the channel start. In some aspects, the UE120may use the reference frequency to determine at least one of a pseudo-noise sequence for reference signals used after configuration (e.g., radio resource control (RRC) configuration) of the UE120, a RB group (RBG) of the UE120, a precoder RB (PRB) granularity of the UE120, and/or a location of a sounding reference signal (SRS) of the UE120. In such a case, a channel start and/or a channel end of the carrier need not be aligned with the RBG, the PRG, or the SRS. In this way, different UEs that are configured with different bandwidths may share commonly-configured sequences and/or the like.

In some aspects, the UE120may use the channel number to determine the configuration. For example, the UE120may identify a center frequency or an identity of a channel in which the carrier is allocated according to the channel number.

In some aspects, the UE120may use the number of RBs to identify the channel end of the carrier and/or a bandwidth of the carrier. For example, the UE120may identify the channel end according to an offset, from the channel start, that is identified by the number of RBs of the carrier.

In some aspects, the UE120may use the tone boundary offset value to determine the configuration. For example, in a situation where the carrier includes an odd number of RBs, the UE120may use the tone boundary offset value to determine the tone boundary offset.

In some aspects, the carrier information may refer to a bandwidth part. For example, the UE120may determine a configuration of a bandwidth part associated with the carrier identified by the carrier information. In such a case, the BS110may provide information identifying a starting RB and an ending RB of the bandwidth part within the carrier. For example, the starting RB and/or the ending RB can be defined relative to the carrier, or relative to the reference frequency.

In some aspects, the UE120may be associated with frequency division duplexing (FDD). In such a case, different sets of parameters can be signaled for a downlink carrier than for an uplink carrier. For example, different sets of parameters may be signaled when the subcarrier spacing is different for the downlink carrier than for the uplink carrier. Additionally, or alternatively, different sets of parameters may be signaled when the channel bandwidth is different for the downlink carrier than for the uplink carrier. When the channel bandwidth and subcarrier spacings of the downlink carrier and the uplink carrier are equal, the BS110may indicate only a channel number of the uplink carrier in addition to the parameters of the downlink carrier.

In some aspects, the UE120may be associated with time division duplexing (TDD). In such a case, the channel number of the downlink carrier may be equal to the channel number of the uplink carrier. In some aspects, the BS110may signal a different number of RBs for the downlink carrier than for the uplink carrier (e.g., when the downlink carrier is associated with a different number of RBs than the uplink carrier).

In some aspects, the BS110and the UE120may perform off-raster synchronization. For example, the BS110may transmit synchronization signal blocks based at least in part on a synchronization raster which may identify particular resources in which the BS110is to transmit synchronization signal blocks. In some aspects, the BS110may transmit a synchronization signal block in an off-raster location (e.g., a location not identified by the synchronization raster). For example, the BS110may transmit the synchronization signal block in the off-raster location to enable the UE120to determine mobility information for mobility management. The techniques and apparatuses described herein are applicable for off-raster synchronization as well as for synchronization according to the synchronization raster. For example, the UE120may determine the resource allocation based at least in part on the synchronization signal block (e.g., based at least in part on a reference frequency identified by the synchronization signal block) irrespective of whether the synchronization signal block is on or off the synchronization raster.

In some aspects, a change in channel number can be observed as a continuous phase rotation of the transmitted signal (e.g., the carrier information). This may be based at least in part on the Fourier transform used to generate the transmitted signal. Additionally, a change in k0may be observed as a phase rotation of the transmitted signal that may reset at every signal boundary.

By determining the physical channel, the tone boundary offset, the channel start, and/or the channel end, the UE120determines the configuration of the channel. In this way, the UE120determines the configuration without explicit signaling of certain parameters of the configuration (e.g., the channel start, the channel end, a center frequency of the carrier, etc.), which improves efficiency of signaling the carrier information and improves utilization of network resources.

As indicated above,FIG. 6is provided as an example. Other examples are possible and may differ from what was described with respect toFIG. 6.

FIG. 7is a diagram illustrating an example process700performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process700is an example where a UE (e.g., UE120) performs a determination of a configuration for a carrier based at least in part on carrier information.

As shown inFIG. 7, in some aspects, process700may include receiving carrier information identifying at least one of an initial absolute frequency for a carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency (block710). For example, the UE may receive carrier information from a BS (e.g., BS110). The UE may receive the carrier information to determine a configuration for a carrier or BWP of the UE. The carrier information may identify at least one of an initial absolute frequency for the carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency. For example, the carrier information may identify the initial absolute frequency, the tone boundary offset value, the number of resource blocks, and the frequency offset. The initial absolute frequency may identify a frequency relative to which the carrier or BWP is defined (e.g., based at least in part on the tone boundary offset value, the frequency offset, and/or the like).

As shown inFIG. 7, in some aspects, process700may include determining a configuration of the carrier based at least in part on the carrier information and a subcarrier spacing of the UE (block720). For example, the UE may determine a configuration of the carrier. The UE may determine the configuration using the carrier information. For example, the UE may know the subcarrier spacing of the UE, and may use the carrier information, based at least in part on the subcarrier spacing, to determine the configuration.

Process700may include additional aspects, such as any single aspect and/or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In some aspects, the reference frequency is located a particular distance from an edge of the carrier, wherein the particular distance is wider than a maximum supported channel bandwidth of the UE. In some aspects, the UE may determine, based at least in part on the reference frequency, at least one of a pseudo-noise sequence for the carrier, a resource block group for the carrier, a precoder resource block granularity for the carrier, or a location of a sounding reference signal for the carrier.

In some aspects, the UE may determine a bandwidth part based at least in part on the carrier information and based at least in part on information identifying at least one of a starting resource block of the bandwidth part or an ending resource block of the bandwidth part. In some aspects, at least one of the starting resource block of the bandwidth part or the ending resource block of the bandwidth part are defined relative to the physical channel. In some aspects, at least one of the starting resource block of the bandwidth part or the ending resource block of the bandwidth part are defined relative to the reference frequency.

In some aspects, the carrier is a downlink carrier and the carrier information is downlink carrier information, and, when the UE is associated with frequency division duplexing, the UE may receive uplink carrier information for an uplink carrier; and determine a configuration of the uplink carrier based at least in part on the uplink carrier information. In some aspects, the UE is configured to receive the uplink carrier information based at least in part on the uplink carrier being associated with at least one of a different subcarrier spacing than the downlink carrier, or a different channel bandwidth than the downlink carrier.

In some aspects, when subcarrier spacings of the downlink carrier and the uplink carrier are equal and when channel bandwidths of the downlink carrier and the uplink carrier are equal, the uplink carrier information identifies a channel number of the uplink carrier. In some aspects, a synchronization signal block for the carrier is received in a location other than a location defined by a synchronization raster for the physical channel.

In some aspects, the UE may identify the initial absolute frequency based at least in part on one of: receiving a channel number indicating the initial absolute frequency, or detecting a synchronization channel at the initial absolute frequency.

AlthoughFIG. 7shows example blocks of process700, in some aspects, process700may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIG. 7. Additionally, or alternatively, two or more of the blocks of process700may be performed in parallel.

FIG. 8is a diagram illustrating an example process800performed, for example, by a base station (BS), in accordance with various aspects of the present disclosure. Example process800is an example where a base station (e.g., BS110) performs signaling of carrier information in a 5G network.

As shown inFIG. 8, in some aspects, process800may include determining a configuration of a carrier for a UE based at least in part on a subcarrier spacing of the UE (block810). For example, the base station may determine a configuration for a carrier. In some aspects, the base station may determine the configuration for a bandwidth part of the UE (e.g., that is included in the carrier). In some aspects, the base station may determine the configuration based at least in part on a subcarrier spacing of the UE.

As shown inFIG. 8, in some aspects, process800may include transmitting carrier information identifying the configuration (block820). For example, the base station may transmit carrier information to the UE. The carrier information may identify the configuration and/or may be used by the UE to determine the configuration. For example, the carrier information may include at least one of an initial absolute frequency for the carrier, a tone boundary offset value for the carrier, a number of resource blocks included in the carrier, or a frequency offset from a reference frequency.

Process800may include additional aspects, such as any single aspect and/or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In some aspects, the reference frequency is located a particular distance from an edge of the carrier, wherein the particular distance is wider than a maximum supported channel bandwidth of the UE. In some aspects, the base station may transmit information identifying at least one of a starting resource block of a bandwidth part or an ending resource block of the bandwidth part, wherein the carrier information is for the bandwidth part. In some aspects, at least one of the starting resource block of the bandwidth part or the ending resource block of the bandwidth part are defined relative to the physical channel. In some aspects, at least one of the starting resource block of the bandwidth part or the ending resource block of the bandwidth part are defined relative to the reference frequency. In some aspects, the carrier is a downlink carrier and the carrier information is downlink carrier information. When the UE is associated with frequency division duplexing, the base station may transmit uplink carrier information for an uplink carrier. In some aspects, the base station is configured to transmit the uplink carrier information based at least in part on the uplink carrier being associated with at least one of: a different subcarrier spacing than the downlink carrier, or a different channel bandwidth than the downlink carrier.

In some aspects, when subcarrier spacings of the downlink carrier and the uplink carrier are equal and when channel bandwidths of the downlink carrier and the uplink carrier are equal, the uplink carrier information identifies a channel number of the uplink carrier. In some aspects, a synchronization signal block for the carrier is received in a location other than a location defined by a synchronization raster for the physical channel. In some aspects, the initial absolute frequency is identified based at least in part on one of: a channel number indicating the initial absolute frequency, or a synchronization channel at the initial absolute frequency.

AlthoughFIG. 8shows example blocks of process800, in some aspects, process800may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIG. 8. Additionally, or alternatively, two or more of the blocks of process800may be performed in parallel.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of the aspects.

As used herein, the term component is intended to be broadly construed as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software.