Patent Description:
Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for a narrowband reference signal (NRS) for a user equipment (UE) specific discontinuous reception (DRX) cycle.

Document <CIT> discuss how to implement discontinuous reception (DRX) for a UE when wake-up signals (WUSs) are configured, and how to implement DRX for a UE when WUSs are not configured. WUSs are paging signals sent over a physical downlink shared channel (PDSCH) that "wake up" a user device from an idle state so that it can prepare to receive data. Document <CIT> discuss systems, methods, and/or apparatuses for "extended DRX (e-DRX) operation using hyper frame extension signalling. The hyper frame extension signalling may extend the system frame number (SEN) range while maintaining backward compatibility for legacy devices not configured to use the extended SEN range. A UE can request a different UE-specific DRX cycle within an attach request. The range of values that the UE can request are the same as the available values for the cell-specific DRX cycle. Document <CIT> discuss systems, methods, and/or apparatuses for extended discontinuous reception (DRX) operation. The UE "may communicate with a base station by receiving an el-DRX configuration. Document D3 specifies "the UEs <NUM> and base stations are configured for extended DRX (e-DRX) operation using hyper-SFN extension signaling.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the accompanying drawings, specification, and appendices.

The BSs may also communicate with one another (e.g., directly or indirectly) via a wireless or wireline backhaul.

Similarly, FR2 is often referred to as a "millimeter wave" band despite being different from the extremely high frequency (EHF) band (<NUM> to <NUM>) which is identified by the International Telecommunications Union (ITU) as a "millimeter wave" band.

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

In some aspects, UE <NUM> may include means for identifying a set of time instances to monitor for paging, wherein the set of time instances are identified based at least in part on a first DRX cycle parameter set; means for identifying a subset of time instances, of the set of time instances, for which an NRS is to be monitored irrespective of whether paging is present on the subset of time instances, wherein the subset of time instances is identified based at least on a second DRX cycle parameter set; means for communicating based at least on the set of time instances and the subset of time instances; and/or the like. In some aspects, such means may include one or more components of UE <NUM> described in connection with <FIG>, such as controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, and/or the like.

In some aspects, base station <NUM> may include means for identifying a set of time instances for paging associated with a UE, wherein the set of time instances are identified based at least in part on a first DRX cycle parameter set; means for identifying a subset of time instances, of the set of time instances, for which an NRS is to be transmitted irrespective of whether paging is transmitted on the subset of time instances, wherein the subset of time instances is identified based at least on a second DRX cycle parameter set; means for communicating based at least on the set of time instances and the subset of time instances; and/or the like. In some aspects, such means may include one or more components of base station <NUM> described in connection with <FIG>, such as antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, and/or the like.

Some types of UEs, such as low-power UEs or high-efficiency UEs (e.g., IoT UEs, NB-IoT UEs, eMTC UEs, and/or the like) may communicate using a narrow band relative to a baseline bandwidth. A narrowband reference signal (NRS) may be used as a cell-specific reference signal for narrowband deployments. An NRS may be used by the UE for cell search and initial acquisition, downlink channel quality measurements, channel estimation for coherent demodulation and/or detection at the UE, and/or the like. In some aspects, the NRS may be transmitted in a non-anchor carrier. For example, the NRS may be transmitted in the non-anchor carrier whether or not paging is present on a paging occasion that includes the NRS. To reduce overhead associated with the NRS, not all paging occasions may have an associated NRS. For example, for a case with a large density of paging occasions, every other paging occasion may have an NRS.

A UE may monitor for paging based at least in part on a discontinuous reception (DRX) cycle. For example, the DRX cycle may specify how often a UE is to monitor a paging occasion for paging. A paging message may include downlink control information (DCI) scrambled with a paging radio network temporary identifier (P-RNTI) for a UE to which the paging message is directed. In some aspects, a DRX cycle may be defined based at least in part on a DRX cycle parameter, which may identify a number of radio frames (or an amount of time corresponding to the number of radio frames) in between each paging occasion for which the UE is to monitor for paging. For example, a DRX cycle parameter (T) of <NUM> radio frames may mean that a UE awakes on every <NUM>th radio frame to monitor a paging occasion for paging.

The combination of (i) not all paging occasions having an associated NRS and (ii) the DRX cycle of the UE may lead to potential unfairness across UEs, since some UEs may always detect an NRS, and other UEs may never detect an NRS. For example, consider the case of one paging occasion per radio frame, a DRX cycle parameter of <NUM> radio frames, and NRSs on every other paging occasion (and therefore every other radio frame, since there is one paging occasion per radio frame). In this case, with <NUM> UE groups (where a UE group of a UE is identified by UE_ID mod <NUM>), the presence of an NRS may be as shown in Table <NUM>:.

It can be seen that even-indexed UE groups may always be associated with an NRS, whereas odd-indexed UE groups may never be associated with an NRS. In some aspects, an offset may be used so that the UE groups that are associated with an NRS in a first DRX cycle are not associated with the NRS in a second DRX cycle, and so that UE groups that are associated with no NRS in the first DRX cycle are associated with an NRS in the second DRX cycle, as shown in Table <NUM>:.

Generally, the equation for the presence of the NRS on a given radio frame may be of the form: <MAT> where: PO_Index is the index of the paging occasion (PO) within one DRX cycle: <MAT> <MAT> and T is the DRX cycle measured in radio frames. If R = <NUM>, the PO is associated with an NRS. If R = <NUM>, the PO is not associated with an NRS. A paging occasion may be referred to herein as being associated with a time instance. For example, a UE may identify a set of time instances associated with paging occasions, a set of time instances associated with NRSs, and/or the like.

The above configurations may be for cell-specific DRX cycles (e.g., configured for a particular cell). However, in some aspects, a DRX cycle may be UE-specific. For example, a UE may be configured with a DRX cycle parameter specific to the UE, and may monitor for paging based at least in part on the UE-specific DRX cycle parameter and/or a cell-specific DRX cycle parameter. In this case, if each UE follows a respective UE-specific DRX cycle to derive the presence of the NRS, network overhead may be increased because the base station may need to transmit an NRS on a given paging occasion if any one or more UEs expects an NRS on the given paging occasion.

Some techniques and apparatuses described herein provide for the determination of a set of time instances associated with paging occasions, and a subset of time instances, of the set of time instances, associated with NRSs. For example, the UE may determine the set of time instances based at least in part on a first DRX cycle parameter set (e.g., associated with one or more first DRX cycles, such as a cell-specific DRX cycle, a UE-specific DRX cycle, and/or the like) and may determine the subset of time instances based at least in part on a second DRX cycle parameter set (e.g., associated with one or more second DRX cycles, such as a cell-specific DRX cycle, a UE-specific DRX cycle, and/or the like). The determination of the subset of time instances may reduce the number of NRSs to be transmitted by the base station, as described in more detail elsewhere herein. Thus, network overhead and communication resource utilization may be reduced and communication resources of the base station may be conserved.

<FIG> is a diagram illustrating an example <NUM> of determination of NRS time instances using a cell-specific DRX cycle parameter set, in accordance with various aspects of the present disclosure. As shown in <FIG>, example <NUM> includes a UE <NUM> and a BS <NUM>. While the operations described in connection with <FIG> are shown as performed by a single BS <NUM>, in some aspects, some or all of these operations may be performed by two or more different BSs <NUM> or a network associated with the BS <NUM> (e.g., a gNB, a central unit, a network controller, and/or the like).

As shown in <FIG>, and by reference number <NUM>, the BS <NUM> provides information identifying a UE-specific DRX cycle parameter set to the UE <NUM>. For example, the UE-specific DRX cycle parameter set identifies a DRX cycle length (e.g., a value of T) to be used by the UE <NUM>. In some aspects, the BS <NUM> may configure multiple UEs <NUM> (e.g., UEs <NUM> covered by the BS <NUM> or connected to a cell provided by the BS <NUM>) with respective UE-specific DRX cycle parameter sets. In some cases, the UE-specific DRX cycle may be set by a network entity other than the BS <NUM> (e.g., a mobility management entity (MME) and/or the like), and the BS <NUM> may transmit this configuration over the air interface to the UE <NUM>. In some aspects, the information identifying a UE-specific DRX cycle parameter set may be communicated via radio resource control (RRC) signaling and/or the like.

As shown by reference number <NUM>, the BS <NUM> provides information identifying a cell-specific DRX cycle parameter set to the UE <NUM>. For example, the cell-specific DRX cycle parameter set identifies a DRX cycle length (e.g., a value of T) that is associated with a cell provided by the BS <NUM>. In some aspects, the BS <NUM> configures UEs <NUM> covered by the BS <NUM> or connected to the cell provided by the BS <NUM> with the cell-specific DRX cycle parameter set.

As shown by reference number <NUM>, the UE <NUM> identifies a set of time instances to monitor for paging (e.g., a set of paging occasions) based at least in part on the UE-specific DRX cycle parameter set and/or the cell-specific DRX cycle parameter set. For example, the UE <NUM> identifies the set of paging occasions using a smaller value of the UE-specific DRX cycle parameter set and the cell-specific DRX cycle parameter set. More particularly, if the UE-specific cycle parameter set is T = <NUM> radio frames and the cell-specific DRX cycle parameter is T = <NUM> radio frames, then the UE <NUM> may identify a paging occasion every <NUM> radio frames. In some aspects, the UE <NUM> may use a larger value of the UE-specific DRX cycle parameter and the cell-specific DRX cycle parameter, or a different combination of the UE-specific DRX cycle parameter and the cell-specific DRX cycle parameter.

As shown by reference number <NUM>, the UE <NUM> identifies a subset of time instances for which the NRS is to be monitored based at least in part on the cell-specific DRX cycle parameter set. The subset of time instances may be a subset (e.g., a proper subset or another type of subset) of the set of time instances. In some aspects, the UE <NUM> may identify the subset of time instances in the form shown by the below formula: <MAT> where:.

In the above formula, if R = <NUM>, then the corresponding PO is associated with an NRS. If R = <NUM>, then the PO is not associated with an NRS. Thus, the number of POs associated with an NRS is reduced relative to determining the NRS association in accordance with UE-specific DRX cycle configurations of a plurality of UEs. Therefore, network overhead is reduced relative to transmitting NRSs for each of the plurality of UEs in accordance with the respective UE-specific DRX cycle configurations.

As shown by reference number <NUM>, the UE <NUM> and the BS <NUM> may communicate based at least in part on the set of time instances and the subset of time instances. For example, the BS <NUM> transmits paging on one or more time instances of the set of time instances. As another example, the BS <NUM> may transmit an NRS on one or more of the subset of time instances. The UE <NUM> monitors for paging on the set of time instances and monitors for an NRS on the subset of time instances.

<FIG> is a diagram illustrating an example <NUM> of determination of NRS time instances using a cell-specific DRX cycle parameter set, in accordance with various aspects of the present disclosure. As shown in example <NUM>, the BS <NUM> may configure the UE <NUM> with a first UE-specific DRX cycle parameter set (shown by reference number <NUM>) and a second DRX cycle parameter set (shown by reference number <NUM>).

As shown by reference number <NUM>, the BS <NUM> may provide an indication to the UE <NUM>. The indication may indicate whether the second DRX cycle parameter set includes a single DRX cycle parameter or a plurality of DRX cycle parameters, described in more detail below. It should be noted that, in some aspects, the BS <NUM> may not provide the information shown by reference number <NUM>. For example, the UE <NUM> may determine the information shown by reference number <NUM>. In some aspects, a specification may define whether the second DRX cycle parameter set includes a single parameter or a plurality of parameters. In some aspects, the indication shown by reference number <NUM> may be explicit (e.g., a bit in a system information block), or may be implicit. In such a case, if the UE <NUM> receives a system information block parameter indicating support of UE-specific DRX and if the parameter is set to ON, then the UE <NUM> may determine that the second DRX cycle parameter includes a plurality of parameters. Otherwise, the UE <NUM> may determine that the second DRX cycle parameter includes a single parameter.

As shown by reference number <NUM>, the UE <NUM> may identify the set of time instances based at least in part on the first UE-specific DRX cycle parameter set and/or based at least in part on a cell-specific DRX cycle parameter set. The configuration of the cell-specific DRX cycle parameter set is not shown in <FIG>. The identification of the set of time instances in accordance with the first UE-specific DRX cycle parameter set and/or the cell-specific DRX cycle parameter set is described in more detail in connection with <FIG>.

As shown by reference number <NUM>, the UE <NUM> may identify the subset of time instances based at least in part on the second DRX cycle parameter set. For example, the UE <NUM> may identify the subset of time instances based at least in part on whether the second DRX cycle parameter set includes a single UE-specific DRX cycle parameter (e.g., a single value of T), or multiple UE-specific DRX cycle parameters (e.g., multiple values of T), as indicated by the indication.

In the case that the second DRX cycle parameter set includes a single UE-specific DRX cycle parameter, the UE <NUM> may identify the subset of time instances using the single UE-specific DRX cycle parameter, as described in connection with reference number <NUM> of <FIG>.

In the case that the second DRX cycle parameter includes a plurality of UE-specific DRX cycle parameters, the UE <NUM> may identify the subset of time instances as follows: <MAT> In some aspects, the plurality of UE-specific DRX cycle parameters (e.g., i = <NUM> through N) may include all UE-specific DRX cycle lengths that are configurable for the UE <NUM>. In some aspects, the plurality of UE-specific DRX cycle parameters may include all UE-specific DRX cycle lengths that are configurable for the UE <NUM> and are shorter than the cell-specific DRX cycle configuration of the UE <NUM>. In some aspects, the plurality of UE-specific DRX cycle parameters may include all UE-specific DRX cycle lengths that are configured for the UE <NUM> in connection with reference number <NUM>.

As shown by reference number <NUM>, the BS <NUM> and the UE <NUM> may communicate based at least in part on the set of time instances and the subset of time instances. This is described in more detail in connection with <FIG>.

<FIG> is a diagram illustrating an example <NUM> of determination of NRS time instances using a DRX cycle parameter set that is for identification of the NRS time instances, in accordance with various aspects of the present disclosure. As shown in example <NUM>, the BS <NUM> may configure the UE <NUM> with a UE-specific DRX cycle parameter set (shown by reference number <NUM>) and a DRX cycle parameter set for identification of the subset of time instances (shown by reference number <NUM>). As shown by reference number <NUM>, the BS <NUM> may configure the UE <NUM> with a cell-specific DRX cycle parameter set.

As shown by reference number <NUM>, the UE <NUM> may identify the set of time instances based at least in part on the UE-specific DRX cycle parameter set and/or based at least in part on the cell-specific DRX cycle parameter set. The identification of the set of time instances in accordance with the UE-specific DRX cycle parameter set and the cell-specific DRX cycle parameter set is described in more detail in connection with <FIG>.

As shown by reference number <NUM>, the UE <NUM> may identify the subset of time instances based at least in part on the DRX cycle parameter set for identification of the subset of time instances. For example, the DRX cycle parameter set for identification of the subset of time instances may identify a value T', and the UE <NUM> may identify the subset of time instances as follows: <MAT> where:
PO_Index is the index of the PO within one DRX cycle: PO_Index = (SFN * Ns * N / T'+ i_s), and <MAT>.

It should be noted that, in examples <NUM>, <NUM>, and <NUM>, the BS <NUM> may perform operations similar to those described in connection with reference numbers <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. For example, the BS <NUM> may identify a set of time instances for paging, and may identify a subset of time instances for which the NRS is to be transmitted, in accordance with the procedures described in connection with reference numbers <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The BS <NUM> may transmit the NRS on the subset of time instances.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where the UE (e.g., UE <NUM> and/or the like) performs operations associated with NRS for a UE-specific discontinuous reception cycle.

As shown in <FIG>, in some aspects, process <NUM> may include identifying a set of time instances to monitor for paging, wherein the set of time instances are identified based at least in part on a first discontinuous reception (DRX) cycle parameter set (block <NUM>). For example, the UE (e.g., using controller/processor <NUM> and/or the like) may identify a set of time instances to monitor for paging, as described above. In some aspects, the set of time instances are identified based at least in part on a first DRX cycle parameter set.

As further shown in <FIG>, in some aspects, process <NUM> may include identifying a subset of time instances, of the set of time instances, for which a narrowband reference signal (NRS) is to be monitored irrespective of whether paging is present on the subset of time instances, wherein the subset of time instances is identified based at least on a second DRX cycle parameter set (block <NUM>). For example, the UE (e.g., using receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may identify a subset of time instances, of the set of time instances, for which an NRS is to be monitored irrespective of whether paging is present on the subset of time instances, as described above. In some aspects, the subset of time instances is identified based at least on a second DRX cycle parameter set.

As further shown in <FIG>, in some aspects, process <NUM> may include communicating based at least on the set of time instances and the subset of time instances (block <NUM>). For example, the UE (e.g., using receive processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) may communicate based at least on the set of time instances and the subset of time instances, as described above.

In a first aspect, the first DRX cycle parameter set comprises a UE-specific DRX cycle length, and the second DRX cycle parameter set comprises a cell-specific DRX cycle length of a cell of the UE.

In a second aspect, alone or in combination with the first aspect, identifying the set of time instances is based at least in part on the first DRX cycle parameter set and the second DRX cycle parameter set.

In a third aspect, alone or in combination with one or more of the first and second aspects, the first DRX cycle parameter set comprises a UE-specific DRX cycle length, and the second DRX cycle parameter set comprises a plurality of UE-specific DRX cycle lengths.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the plurality of UE-specific DRX cycle lengths include all UE-specific DRX cycle lengths configurable for the UE.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the plurality of UE-specific DRX cycle lengths include all UE-specific DRX cycle lengths shorter than or equal to a cell-specific DRX cycle length of a cell of the UE.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, the plurality of UE-specific DRX cycle lengths are configured for the UE.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, process <NUM> includes receiving an indication of whether the second DRX cycle parameter set includes a plurality of DRX cycle configurations or a single DRX cycle configuration.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the first DRX cycle parameter set corresponds to a UE-specific DRX cycle length, and the second DRX cycle parameter set corresponds to a DRX cycle length for identification of the subset of time instances associated with the NRS.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a base station, in accordance with various aspects of the present disclosure. Example process <NUM> is an example where the base station (e.g., base station <NUM> and/or the like) performs operations associated with NRS for a UE-specific DRX cycle.

As shown in <FIG>, in some aspects, process <NUM> may include identifying a set of time instances for paging associated with a UE, wherein the set of time instances are identified based at least in part on a first DRX cycle parameter set (block <NUM>). For example, the base station (e.g., using controller/processor <NUM> and/or the like) may identify a set of time instances for paging associated with a UE, as described above. In some aspects, the set of time instances are identified based at least in part on a first DRX cycle parameter set.

As further shown in <FIG>, in some aspects, process <NUM> may include identifying a subset of time instances, of the set of time instances, for which an NRS is to be transmitted irrespective of whether paging is transmitted on the subset of time instances, wherein the subset of time instances is identified based at least on a second DRX cycle parameter set (block <NUM>). For example, the base station (e.g., using controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, and/or the like) may identify a subset of time instances, of the set of time instances, for which an NRS is to be transmitted irrespective of whether paging is transmitted on the subset of time instances, as described above. In some aspects, the subset of time instances is identified based at least on a second DRX cycle parameter set.

As further shown in <FIG>, in some aspects, process <NUM> may include communicating based at least on the set of time instances and the subset of time instances (block <NUM>). For example, the base station (e.g., using controller/processor <NUM>, transmit processor <NUM>, TX MIMO processor <NUM>, MOD <NUM>, antenna <NUM>, and/or the like) may communicate based at least on the set of time instances and the subset of time instances, as described above.

In a first aspect, the first DRX cycle parameter set comprises a UE-specific DRX cycle length of the UE, and the second DRX cycle parameter set comprises a cell-specific DRX cycle length of the base station.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, the plurality of UE-specific DRX cycle lengths include all UE-specific DRX cycle lengths shorter than or equal to a cell-specific DRX cycle length of the base station.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, process <NUM> includes configuring the plurality of UE-specific DRX cycle lengths for the UE.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, process <NUM> includes transmitting an indication of whether the second DRX cycle parameter set includes a plurality of DRX cycle configurations or a single DRX cycle configuration.

As used herein, the term "component" is intended to be broadly construed as hardware, software, and/or a combination of hardware and software. As used herein, a processor is implemented in hardware, software, and/or a combination of hardware and software. Software is to be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, and/or the like, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware, software, and/or a combination of hardware and software.

Claim 1:
A method of wireless communication performed by a user equipment, UE, (<NUM>) comprising:
identifying (<NUM>) a set of time instances to monitor for paging, wherein the set of time instances are identified based at least in part on a first discontinuous reception, DRX, cycle parameter set or a second DRX cycle parameter set, whichever of the first DRX cycle parameter set or the second DRX cycle parameter set has the smallest cycle length, the first DRX cycle parameter set comprising a UE-specific DRX cycle length and the second DRX cycle parameter set comprising a cell-specific DRX cycle length of a cell of the UE;
identifying (<NUM>) a subset of time instances, of the set of time instances, for which a narrowband reference signal, NRS, is to be monitored irrespective of whether paging is present on the subset of time instances, wherein the subset of time instances is identified based at least on the second DRX cycle parameter set; and
communicating (<NUM>) based at least on the set of time instances and the subset of time instances.