Patent Publication Number: US-2021195587-A1

Title: Broadcast operation with bi-directional subframe slots in multibeam deployment

Description:
FIELD 
     The subject matter described herein relates to wireless. 
     BACKGROUND 
     The cellular system including the Fifth Generation (5G) system may support an increasing number of devices and services including applications with a wide range of use cases and diverse needs with respect to bandwidth, latency, and reliability requirements. For example, multiple input, multiple output technology may be used to increase throughput/data rate. The system may also be configured to support machine-to-machine communications as well as ultra-reliable, low latency services. 
     SUMMARY 
     Methods and apparatus, including computer program products, are provided for use of bi-directional slots of a subframe. 
     In some example embodiment, there may be provided an apparatus that includes at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to at least determine a threshold indicative of downlink symbol availability in at least one bi-directional slot of a subframe and monitor for an occasion covering the at least one bi-directional slot, when the threshold indicates the availability of downlink symbols in the at least one bi-directional slot. 
     In some variations, one or more of the features disclosed herein including the following features can optionally be included in any feasible combination. The threshold may provide an indication of a current usage of downlink symbols in a bi-directional slot and corresponding available symbols in the bi-directional slot which can serve as the occasion. The occasion may include a paging occasion, other system information occasion, and/or a random access response. 
     The above-noted aspects and features may be implemented in systems, apparatus, methods, and/or articles depending on the desired configuration. The details of one or more variations of the subject matter described herein are set forth in the accompanying drawings and the description below. Features and advantages of the subject matter described herein will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       In the drawings, 
         FIG. 1  depicts an example of a UL-DL slot pattern including a bi-directional, flexible slot, in accordance with some example embodiments; 
         FIG. 2  depicts an example of a system including a user equipment configured to utilize paging occasions including at least one bi-directional slot, in accordance with some example embodiments; 
         FIG. 3  depicts an example of a process for utilizing paging occasions including at least one bi-directional slot, in accordance with some example embodiments; 
         FIG. 4  depicts an example of an apparatus, in accordance with some example embodiments; 
         FIG. 5  depicts block candidate location patterns, in accordance with some example embodiments; and 
         FIG. 6  depicts an example search space on the physical downlink control channel, in accordance with some example embodiments. 
     
    
    
     Like labels are used to refer to same or similar items in the drawings. 
     DETAILED DESCRIPTION 
     In the cellular system including the Fifth Generation (5G) cellular system, paging will be more complex, when compared to prior cellular systems, due to many of 5G&#39;s features, such as multiple input, multiple output technology (MIMO), for example. As such, the user equipment (UE) task of determining when there is a paging occasion to monitor a page is more complex. The paging occasion (which is within a paging frame) defines a specific time during which a UE checks for a paging message. 
     For paging, the cellular network may provide to the UE information including parameters. These parameters may be received, via signaling, broadcast, and/or the like, and these parameter may include the paging occasion configuration, such as time offset in a frame, duration, periodicity, and/or the like. Moreover, the physical downlink control channel (PDCCH) configuration may provide the UE with the search space configuration including the monitoring occasions within a paging occasion. For paging, the core resource set (CORESET) configuration may reuse the same configuration for the remaining minimum system information (RMSI) CORESET as indicated in the physical broadcast channel (PBCH). In addition, the UE may assume quasi-colocation (QCL) between synchronization signal (SS) blocks, paging downlink control information/indicators (DCs), and paging messages. Moreover, the UE may not be required to soft combine multiple paging DCIs within one paging occasion. Furthermore, the air interface support by the UE and base station may also support the sending of so-called “short paging messages,” such as a systemInfoModification, cmas-Indication, and/or etws-Indication, as part of the paging DCI. 
     MIMO technology, as noted, may be supported, so multi-beam operations may increase the complexity of paging. To that end, the length in time (e.g., duration) of a paging occasion may be set to one period of a beam sweep, and the same paging message may be repeated in all beams of the sweeping pattern. As such, a single paging occasion may cover the entire beam sweep, so a UE&#39;s monitoring pattern may take this into account as well. 
     The UE may receive from the network a system information block (SIB), such as a SIB type 1. When this is the case, the SIB 1 may provide the UE with information to enable uplink (UL) and downlink (DL) slot configuration. For example, the UL/DL slot configuration may be determined via one or two concatenated slot patterns, which repeat in time to form an Uplink/Downlink time division duplex (TDD) configuration. The configuration for each pattern indicates the slots of a subframe defined as downlink slots (“D”) containing only DL symbols, bi-directional (e.g., flexible, ‘X’) slots allowing both downlink and uplink symbols, or uplink only slots (‘U’) containing only UL symbols. 
     The pattern may have a time period configured that is based in part on the sub-carrier spacing to enable a determination of the slots within a subframe of a frame. The configuration for each pattern may provide the quantity (e.g., number) of DL only slots (from the start of the time period), the quantity of DL symbols from the start of the slot that are deemed bi-directional, the quantity of UL only slots (from the end of the time period), and the quantity of UL symbols from the end of the slot that are deemed as bi-directional. Slots that fall within the time period, and are not set as DL-only or UL-only slots are bi-directional slots. The slot represents a subframe portion associated with at least one symbol. 
     To illustrate further, a UE may be scheduled to receive, in the downlink, only in DL symbols (“D”) portion or the flexible symbols (“X”) portion. Similarly, the UE may be schedule to transmit only in the UL symbols (“U”) portion or flexible symbols (“X”) portion. For the flexible slots (which would be the remaining slots among the DL only (“D”) slots and UL only (“U”) slots), the symbol partition in the flexible slots may be determined. This may be determined by determining the number of DL only symbols (from the start of the slot) and UL only symbols (from the end of the slot), while the remaining symbols in between may be considered flexible symbols. 
       FIG. 1  depicts an example of a flexible UL/DL configuration pattern  110  showing the slots in the subframe allocated to a downlink transmission (labeled D), allocated to an uplink transmission (labeled U), and the flexible slots (labeled X) which can be allocated flexibly to the uplink or the downlink, as noted. The pattern  110  may repeat over a period, such as over a time period of a frame, beam sweep, and/or the like. For example, a beam sweep may represent a beam at a given time and location. 
     3GPP 38.213 explains that for random access channel (RACH) occasion mapping, if a UE is provided a first higher layer parameter (e.g., tdd-UL-DL-ConfigurationCommon) or is also provided second, higher layer parameter (e.g., tdd-UL-DL-ConfigurationCommon2), the valid physical RACH (PRACH) occasions are those occasions that include uplink symbols or flexible symbols that start at least N gap  symbols after a last downlink symbol or a last SS/PBCH block transmission symbol where N gap  is provided in table, such as Table 1 below (which may be in accordance with a standard, see, e.g., Table 8.1-2 in 3GPP TS 38.213; see also R1-1805795, 3GPP TSG-RAN1, Meeting #92bis, Sanya, China, Apr. 16-20, 2018), as a function of the preamble subcarrier spacing value. For preamble format B4 for example, the N gap =0. In the case of RACH occasion, these occasions may represent when the UE may send a PRACH, which can also be monitored by the base station. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Preamble subcarrier 
                   
               
               
                 spacing 
                 N gap   
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 1.25 kHz or 5 kHz 
                 0 
               
               
                 15 kHz or 30 kHz or 60 
                 2 
               
               
                 kHz 
                   
               
               
                 120 kHz 
                 2 or 3 
               
               
                   
               
            
           
         
       
     
     The time domain resource allocation (RA) for the physical downlink shared channel (PDSCH) may be performed via the 4 bit resource allocation field of the DCI. The default interpretation of the resource allocation field may be determined in accordance with a standard, such as 3GPP TS 38.214, although the time domain resource allocation may be provide to, and configured at, the UE via broadcast or dedicated signaling from the network, such as a base station including the new radio (NR) node B (gNB). The supported physical downlink shared channel (PDSCH) allocation sizes may be for the Type A primary synchronization channel (PSCH) mapping (3, . . . , or 14) and for the physical downlink shared channel (PDSCH) Type B (e.g., sub-slot based scheduling) mapping (2, 4, or 7). This physical downlink shared channel (PDSCH) mapping type may be provided by the PDSCH time domain resource allocation, which may be in accordance with a standard, such as 3GPP TS 38.214. 
     In Long Term Evolution (LTE), the paging frame (PF) calculation indicates where in the radio frame the UE needs to listen for paging. The paging occasion calculation may have subframe accuracy to enable the UE to listen to a paging DCI (which is the indicator/information allocating resources for the paging message). 
     In the 5G new radio (NR) system, the paging occasion calculation may not be as straightforward as in previous generations of wireless systems, in which fixed time division duplex (TDD) patterns and fixed numerology with respect to frame structure are implemented. In the 5G NR&#39;s numerology, there can be variations in the subcarrier spacing of 15 kHz, 30 kHz, 60 kHz, and 120 kHz for data and control, and these variations also affect slot allocations as well. Moreover, the 5G NR&#39;s flexible TDD patterns (in which any slot of a subframe can be configured as a downlink slot, an uplink slot, or a flexible slot) may lead to variation that makes paging occasion determination more complex, when compared to previous cellular systems. Indeed, the determination of the paging occasion can, if not property performed, lead to discrepancies and wasted power and resources. 
     In order to enable the base station, such as a 5G New Radio (NR) gNB base station, beam sweep to be performed during the paging occasion, the duration of the paging occasion may need to be extended to cover multiple slots of a subframe of a frame. Depending on the paging occasion time/location, certain slots during the beam sweep may be of type DL (D) only, UL (U) only, or flexible (X). 
     Although uplink slots (U) may not be useable by the UE to receive a page, downlink slots may be used. With respect to the flexible (X) slots, their usage by the UE to receive a page may depends on a variety of factors. Similarly, the system information (SI) window may need to cover an entire beam sweep over which different types of slots may be present. Moreover, the RACH response (RAR) window may be 10 ms for example, which with 120 kHz carrier spacing translates to 80 slots, so enforcing the slots to be DL only slots (or, for example, with very limited UL allocation) may heavily and inefficiently restrict DL/UL allocations. 
     In some example embodiments, the user equipment (UE) may determine the validity of bi-directional slots (e.g., the flexible, X slots depicted at  FIG. 1 ) for scheduling of a paging occasion. This determination may be based on the condition of the quantity of available symbols. In some example embodiments, this determination may be based on a threshold, which is further described below. 
     Alternatively or additionally, the UE may determine the validity of bi-directional slots (e.g., the flexible, X slots) for RAR scheduling or other system information (OSI) window reception. This determination may be based on the condition of the quantity of available symbols. In some example embodiments, this determination may be based on a threshold, which is further described below. 
     In some example embodiments, the UE may determine, based on a threshold, the validity of a bi-directional slot (e.g., the flexible, X slot) for scheduling of paging occasion or monitoring of RAR, OSI, and/or the like. For example, the threshold may provide an indication of the availability of downlink (DL) symbols. Specifically, the availability of DL symbols given expected allocations and/or usage at a given time and/or location. If there are an insufficient amount of DL symbols to serve the expected allocations and/or usage, the bi-directional symbols (X) will likely be allocated to satisfy the expected allocations and/or usage, rather than paging (or some other type of monitoring occasion). If however there are a sufficient amount of DL symbols to serve the expected allocations and/or usage, the corresponding bi-directional slot(s) can be used for paging, so the UE can monitor the paging occasion in at least one bi-directional slot. 
     In some example embodiments, the threshold may be defined in accordance with the following: 
         Th   symb   DL   =N   symb   PDSCH   +N   symb   CORESET   Equation 1,
 
     wherein N symb   PDSCH  is the quantity (e.g., number) of symbols to be assumed in use for the physical downlink shared channel (PDSCH) resource allocation (RA), and N symb   CORESET  is the number of symbols used for the CORESET allocation as given by a management information block (e.g. through ‘pdcch.ConfigSIB1’ or via dedicated signalling for example in case of handover or redirection or some other higher layer signalling). For example, the values of N symb   PDSCH  and N symb   CORESET  may be parameters associated with a slot. When this is the case, if a slot has 14 symbols, the N symb   CORESET  will have a value less than 14, such as 1, 2, or 3, while the N symb   PDSCH  may have values anywhere between 1 and 12. 
     Equation 1 above may provide a threshold that prevents using bi-directional symbols (for a given slot) for monitoring a paging occasion on the physical downlink control channel (PDCCH), when there are an insufficient amount of symbols to satisfy the resource requirements of the CORESET and PDSCH. At a given location and a given time, the UE may use the bi-directional slots “X” for paging opportunities or other monitoring tasks, when, based on the threshold, there are available symbols given the symbol resource requirements for the CORESET and PDSCH. 
     The N symb   PDSCH  and N symb   CORESET  values may be determined in a semi-static manner (for example, defined in accordance with a specification, table, mapping table, and/or the like, or provided by higher layer signaling). Alternatively or additionally, the N symb   PDSCH  and N symb   CORESET  values may be determined implicitly and/or directly based on one or more other parameters. Alternatively or additionally, the N symb   PDSCH  and N symb   CORESET  values may be signaled separately (e.g., included in system information, such as a SIB). 
     In some example embodiments, the possible value for N symb   PDSCH  (or range of possible values) may be determined based on the physical downlink shared channel (PDSCH) allocation type {A,B}. For example, if PDSCH allocation type A (e.g., for slot based allocation) is used, the possible range of values for N symb   PDSCH  may be {8, 10, or 12}. And, if the PDSCH allocation type B (e.g., for mini-slot or non-slot based allocation) is used, the N symb   PDSCH  may be {2, 4, or 7}. The allocation type and N symb   PDSCH  may be provided as part of the paging configuration information or as part of system information provided to UE via broadcast signaling or via dedicated signaling. 
     In some example embodiments, the value for N symb   PDSCH  is determined based on the value of other parameter(s) as follows:
         A) N symb   CORESET  size is accounted in the determination of valid value for the N symb   PDSCH , when N symb   CORESET  may be {1, 2, or 3} and N symb   PDSCH  may take values among the group of possible values {2, 4, or 7}, if N symb   CORESET =2, then N symb   PDSCH =4, so that there is one to one or one to many mapping between the valid values of N symb   CORESET  and N symb   PDSCH ;   B) Alternatively or additionally, the value of N RB   CORESET  can be accounted in the determination of valid values of r N symb   PDSCH , for example when N RB   CORESET  may be {24, 48, or 96}, if the N RB   CORESET =24 then N symb   PDSCH =7, or in condition based manner so that when N RB   CORESET  takes value that ≤48, N symb   PDSCH  takes value 7, or when N RB   CORESET  takes value that &gt;48, N symb   PDSCH =4 (e.g., when the available bandwidth is lower than certain threshold use more symbols); and   C) Both N symb   CORESET  and N RB   CORESET  are accounted jointly to determine the value for N symb   PDSCH  for example by first determining the range possible range of values for N symb   PDSCH  based on the value of N RB   CORESET  and then based of value of N symb   CORESET  the value for N symb   PDSCH  is selected among the possible values.       

     Table 2 below presents an example of an implementation of example A above for determining the N symb   PDSCH  value for Equation 1. In example implementations consistent with A, B, or C, the UE may determine the value of N symb   PDSCH  based on given N symb   CORESET  and N RB   CORESET . The value of N symb   CORESET  and N RB   CORESET  may be provided (or determined from) system information (e.g., based on a specification with tables such as Tables 2-4 below). 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 N symb   CORESET   
                 Value of N symb   PDSCH   
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 1 
                 7 
               
               
                   
                 2 
                 4 
               
               
                   
                 3 
                 2 
               
               
                   
                   
               
            
           
         
       
     
     Table 3 below presents an example of an implementation of example B above for determining the N symb   PDSCH  value for Equation 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 N RB   CORESET   
                 Value of N symb   PDSCH   
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 24 
                 7 
               
               
                   
                 48 
                 4 
               
               
                   
                 96 
                 2 
               
               
                   
                   
               
            
           
         
       
     
     Table 4 presents an example of an implementation of example C above for determining the N symb   PDSCH  value for Equation 1. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Value of N symb   PDSCH   
               
            
           
           
               
               
               
               
            
               
                 N symb   CORESET   
                 N RB   CORESET  = 24 
                 N RB   CORESET  = 48 
                 N RB   CORESET  = 96 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 1 
                 7 
                 4 
                 2 
               
               
                 2 
                 7 
                 4 
                 4 
               
               
                 3 
                 7 
                 7 
                 4 
               
               
                   
               
            
           
         
       
     
     Determining the value assumed for N symb   PDSCH  in threshold determination based on N symb   CORESET  and/or N Rb   CORESET  would approximate the coverage requirement, as it can be assumed that the network determines the value for N symb   CORESET  and/or N RB   CORESET  (e.g., through parameter such as “pdcch-ConfigSIB1”) based on the required coverage level. The N symb   CORESET  and N RB   CORESET  provide an indication of the total amount of control channel elements (CCEs, such as resources) available for PDCCH and supported aggregation level, which in term indicates what coverage can be achieved with PDCCH. 
     The value of N RB   CORESET  determines the number of continuous resource blocks (RBs) for the CORESET (e.g., the frequency domain size). Based on 3GPP TS 38.213, the N RB   CORESET  for the CORESET Type0-DPCCH common search space may be determined by ‘pdcch-ConfigSB1’ based on the tables given in TS 38.213 section 13. For example, the CORESET of Type0A-DPCCH (OSI DPCCH) and Type2-DPCCH (paging PDCCH) common search space share the same CORESET configuration as Type0-DPCCH common search space. 
     In some example embodiments, the value assumed for N symb   PDSCH , accounts for the presence of a SS/PBCH block candidate location or the presence of an actually transmitted SS/PBCH block in the slot. For example, if UE is provided by higher-layer signaling the presence of SS/PBCH block in a slot (e.g., for rate matching purposes), the value assumed for N symb   PDSCH  may account for the presence of SS/PBCH block (e.g., so that the value of N symb   PDSCH  is increased). Alternatively or additionally, this may be accounted for in determination of the threshold as follows: 
         Th   symb   DL   =N   symb   PDSCH   +N   symb   CORESET   +N   symb   SSB   Equation2,
 
     wherein N symb   SSB  value is conditioned on the presence of SS/PBCH block candidate location(s) or actually transmitted SS/PBCH block(s) in the slot. In addition or alternatively, the value of N symb   SSB , if SS/PBCH block is present, may depend on, for example, the value N RB   CORESET , so that if the value of N RB   CORESET  is larger than (or equal to) certain threshold, N symb   SSB =2, and if value of N RB   CORESET  is below (or equal to) certain threshold, N symb   SSB =4. This may be used for example to account the needed rate matching of the paging message. In addition or alternatively, the value of N symb   SSB  may depend on the sub-carrier spacing of SS/PBCH block, and its relation to sub-carrier spacing assumed for paging (or some other type of monitoring occasion). The N RB   CORESET  represents a frequency domain allocation of CORESET (control resource set) indicating how many resource blocks (RBs) the CORESET is having in frequency domain. In NR, one RB can have Equation subcarriers in frequency. 
     For each flexible slot (“X”) in a subframe, until all needed monitoring occasions are covered, the possibility of a monitoring occasion to be placed in a bi-directional (flexible, X) slot is determined based on comparing the number of available DL symbols to the determined threshold. The bi-directional (flexible) slot may thus contain the valid search space location (e.g., monitoring occasions), when the quantity of available DL symbols in the bi-directional (flexible) slot, N symb   DL , is equal or larger than Th symb   DL , in other words the N symb   DL ≥Th symb   DL . 
     The number of available DL symbols, N symb   DL , may be determined based on the provided DL/UL slot configuration and signaled RACH configuration (occasions, PRACH configuration index). For the slots, where there are no RACH occasions present, the value for N symb   DL  may be based on the total number of DL symbols and flexible symbols configured. If RACH occasions are possible in the slot, the number of available DL symbols would be determined based on the following: 
         N   symb   DL   =N   symb   slot   −N   start symb   RACH   +N   gap   Equation 3,
 
     wherein:
         N symb   slot  may be obtained (in accordance with, for example, section 4.3.2 of TS 38.211) based on sub-carrier spacing and cyclic prefix (e.g., normal, extended CP) and may corresponds to the total number of symbols in slot,   N start symb   RACH  may be obtained based on PRACH configuration index from random access configuration tables (see, e.g. TS 38.21), and   N gap  is obtained from a table, such as Table 1 above.       

     Alternatively or additionally, the presence of an SS/PBCH block candidate location or the presence of an actually transmitted SS/PBCH block in the slot may be accounted for in the determination of number of available DL symbols, N symb   DL . For example, by reducing from the available DL symbols, by symbols that overlap with SS/PBCH candidate locations or symbols that overlap with the actually transmitted SS/PBCH blocks (or for example determining the number of available DL symbols so that only those DL symbols that are present before the first symbol of actually transmitted SS/PBCH block are accounted or so that only contiguous DL symbols before or after SS/BPCH blocks are accounted in determining the number of available DL symbols). 
     Alternatively or additionally, number of available paging or monitoring (RAR monitoring and/or the like) occasions within the flexible slot may be determined as 
     
       
         
           
             
               N 
               occ 
               DL 
             
             = 
             
               
                 ⌊ 
                 
                   
                     N 
                     symb 
                     DL 
                   
                   
                     Th 
                     symb 
                     DL 
                   
                 
                 ⌋ 
               
               . 
             
           
         
       
     
     When N occ   DL  takes value that is equal or greater than the number of desired paging or monitoring (RAR and/or the like) occasions, then the bi-directional (flexible) slot includes a number of valid paging or monitoring occasions, where the number could be determined by N occ   DL . 
     In some example embodiments, the N occ   DL  may be used to determine the number of valid monitoring occasions in the bi-directional (flexible) slot. In some example embodiments, a condition may be set to value of N occ   DL , so that if the condition exceeds the value of N occ   DL  then the slot in question could be used for paging scheduling, and contain for example N occ   Paging  monitoring occasions. 
       FIG. 2  depicts an example of a portion of a wireless system  200  including at least one user equipment (UE)  210  and at least one base station  250 , in accordance with some example embodiments. 
     The UE  210  may be configured to wirelessly couple to a radio access network being served by a wireless access point, such as a base station  250 , which may be referred to as New Radio (NR) 5G gNB base station. The base station  250  may provide to the UE  210  information that enables the UE to determine the whether a bi-directional slot can be used for a paging and/or monitoring occasion. For example, the base station may provide information to enable a determination of the N symb   PDSCH  and N symb   CORESET  values and/or provide other system or management information to enable a determination of a threshold as described in Equation 1, for example. The UE  210  may then monitor slots  245  including at least one bi-directional slot associated with a paging occasion and/or monitoring occasion, when the threshold indicates the availability of DL symbols. 
     The base station  250  may be coupled to core network, which may include an access and mobility management function (AMF), a visiting session management function (V-SMF), a visiting policy control function (v-PCF), a visiting network slice selection function (v-NSSF), a visiting user plane function (V-UPF), and/or other nodes as well. 
       FIG. 3  depicts an example of a process  300  for determining whether a bi-directional slot of a subframe may monitored as a paging occasion, in accordance with some example embodiments. 
     Although some of the examples describe the use of the threshold to determine a paging occasion, the threshold may be used to determine other monitoring occasions of information broadcast from the base station including other system information, random access response (RAR), and/or the like. 
     At  302 , a user equipment may receive from a network node system information including information indicative of the symbols being used for the physical downlink shared channel (PDSCH) resource allocation (RA) and the number of symbol being used for the CORESET resource allocation, in accordance with some example embodiments. For example, the user equipment may receive from a base station, such as a New Radio gNB base station, system information as part of a master information block and/or system information block. This information may directly or indirectly provide information related to the values of the N symb   PDSCH  and N symb   CORESET . For example, the network may explicitly signal the N symb   PDSCH  and N symb   CORESET  values to the UE. Alternatively or additionally, the network may provide other parameters which can be used to determine the N symb   PDSCH  and N symb   CORESET  values. Alternatively or additionally, the network may provide the allocation type information, as noted above. 
     At  305 , the UE may determine (or obtain) a threshold indicative of DL symbols at a given time and/or location, in accordance with some example embodiments. For example, the UE may determine the threshold based on Equation 1 above. The threshold provides an indication of the current usage of DL symbols in a bi-directional slot, and as such, whether there are any available symbols in the bi-directional slot which can serve as a paging occasion. 
     At  310 , the UE may monitor for a paging occasion (and/or a monitoring occasion), covering at least one bi-directional slot, when the threshold indicates the availability of DL symbols in the at least one slot, in accordance with some example embodiments. As noted, the threshold provides an indication of the usage of DL symbols, so available DL symbols in a bi-directional slot may indicate a possible paging occasion or other type of monitoring occasion for the UE. 
       FIG. 4  illustrates a block diagram of an apparatus  10 , in accordance with some example embodiments. 
     The apparatus  10  may represent a user equipment, such as the user equipment  210 . The apparatus  10 , or portions therein, may be implemented in other network nodes including base stations (e.g., devices  250 ). 
     The apparatus  10  may include at least one antenna  12  in communication with a transmitter  14  and a receiver  16 . Alternatively transmit and receive antennas may be separate. The apparatus  10  may also include a processor  20  configured to provide signals to and receive signals from the transmitter and receiver, respectively, and to control the functioning of the apparatus. Processor  20  may be configured to control the functioning of the transmitter and receiver by effecting control signaling via electrical leads to the transmitter and receiver. Likewise, processor  20  may be configured to control other elements of apparatus  10  by effecting control signaling via electrical leads connecting processor  20  to the other elements, such as a display or a memory. The processor  20  may, for example, be embodied in a variety of ways including circuitry, at least one processing core, one or more microprocessors with accompanying digital signal processor(s), one or more processor(s) without an accompanying digital signal processor, one or more coprocessors, one or more multi-core processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits (for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and/or the like), or some combination thereof. Accordingly, although illustrated in  FIG. 4  as a single processor, in some example embodiments the processor  20  may comprise a plurality of processors or processing cores. 
     The apparatus  10  may be capable of operating with one or more air interface standards, communication protocols, modulation types, access types, and/or the like. Signals sent and received by the processor  20  may include signaling information in accordance with an air interface standard of an applicable cellular system, and/or any number of different wireline or wireless networking techniques, comprising but not limited to Wi-Fi, wireless local access network (WLAN) techniques, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, 802.16, 802.3, ADSL, DOCSIS, and/or the like. In addition, these signals may include speech data, user generated data, user requested data, and/or the like. 
     For example, the apparatus  10  and/or a cellular modem therein may be capable of operating in accordance with various first generation (1G) communication protocols, second generation (2G or 2.5G) communication protocols, third-generation (3G) communication protocols, fourth-generation (4G) communication protocols, fifth-generation (5G) communication protocols, Internet Protocol Multimedia Subsystem (IMS) communication protocols (for example, session initiation protocol (SIP) and/or the like. For example, the apparatus  10  may be capable of operating in accordance with 2G wireless communication protocols IS-136, Time Division Multiple Access TDMA, Global System for Mobile communications, GSM, IS-95, Code Division Multiple Access, CDMA, and/or the like. In addition, for example, the apparatus  10  may be capable of operating in accordance with 2.5G wireless communication protocols General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), and/or the like. Further, for example, the apparatus  10  may be capable of operating in accordance with 3G wireless communication protocols, such as Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA2000), Wideband Code Division Multiple Access (WCDMA), Time Division-Synchronous Code Division Multiple Access (TD-SCDMA), and/or the like. The apparatus  10  may be additionally capable of operating in accordance with 3.9G wireless communication protocols, such as Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and/or the like. Additionally, for example, the apparatus  10  may be capable of operating in accordance with 4G wireless communication protocols, such as LTE Advanced, 5G, and/or the like as well as similar wireless communication protocols that may be subsequently developed. 
     It is understood that the processor  20  may include circuitry for implementing audio/video and logic functions of apparatus  10 . For example, the processor  20  may comprise a digital signal processor device, a microprocessor device, an analog-to-digital converter, a digital-to-analog converter, and/or the like. Control and signal processing functions of the apparatus  10  may be allocated between these devices according to their respective capabilities. The processor  20  may additionally comprise an internal voice coder (VC)  20   a , an internal data modem (DM)  20   b , and/or the like. Further, the processor  20  may include functionality to operate one or more software programs, which may be stored in memory. In general, processor  20  and stored software instructions may be configured to cause apparatus  10  to perform actions. For example, processor  20  may be capable of operating a connectivity program, such as a web browser. The connectivity program may allow the apparatus  10  to transmit and receive web content, such as location-based content, according to a protocol, such as wireless application protocol, WAP, hypertext transfer protocol, HTTP, and/or the like. 
     Apparatus  10  may also comprise a user interface including, for example, an earphone or speaker  24 , a ringer  22 , a microphone  26 , a display  28 , a user input interface, and/or the like, which may be operationally coupled to the processor  20 . The display  28  may, as noted above, include a touch sensitive display, where a user may touch and/or gesture to make selections, enter values, and/or the like. The processor  20  may also include user interface circuitry configured to control at least some functions of one or more elements of the user interface, such as the speaker  24 , the ringer  22 , the microphone  26 , the display  28 , and/or the like. The processor  20  and/or user interface circuitry comprising the processor  20  may be configured to control one or more functions of one or more elements of the user interface through computer program instructions, for example, software and/or firmware, stored on a memory accessible to the processor  20 , for example, volatile memory  40 , non-volatile memory  42 , and/or the like. The apparatus  10  may include a battery for powering various circuits related to the mobile terminal, for example, a circuit to provide mechanical vibration as a detectable output. The user input interface may comprise devices allowing the apparatus  20  to receive data, such as a keypad  30  (which can be a virtual keyboard presented on display  28  or an externally coupled keyboard) and/or other input devices. 
     As shown in  FIG. 4 , apparatus  10  may also include one or more mechanisms for sharing and/or obtaining data. For example, the apparatus  10  may include a short-range radio frequency (RF) transceiver and/or interrogator  64 , so data may be shared with and/or obtained from electronic devices in accordance with RF techniques. The apparatus  10  may include other short-range transceivers, such as an infrared (IR) transceiver  66 , a Bluetooth™ (BT) transceiver  68  operating using Bluetooth™ wireless technology, a wireless universal serial bus (USB) transceiver  70 , a Bluetooth™ Low Energy transceiver, a ZigBee transceiver, an ANT transceiver, a cellular device-to-device transceiver, a wireless local area link transceiver, and/or any other short-range radio technology. Apparatus  10  and, in particular, the short-range transceiver may be capable of transmitting data to and/or receiving data from electronic devices within the proximity of the apparatus, such as within 10 meters, for example. The apparatus  10  including the Wi-Fi or wireless local area networking modem may also be capable of transmitting and/or receiving data from electronic devices according to various wireless networking techniques, including 6LoWpan, Wi-F, Wi-Fi low power, WLAN techniques such as IEEE 802.11 techniques, IEEE 802.15 techniques, IEEE 802.16 techniques, and/or the like. 
     The apparatus  10  may comprise memory, such as a subscriber identity module (SIM)  38 , a removable user identity module (R-UIM), an eUICC, an UICC, and/or the like, which may store information elements related to a mobile subscriber. In addition to the SIM, the apparatus  10  may include other removable and/or fixed memory. The apparatus  10  may include volatile memory  40  and/or non-volatile memory  42 . For example, volatile memory  40  may include Random Access Memory (RAM) including dynamic and/or static RAM, on-chip or off-chip cache memory, and/or the like. Non-volatile memory  42 , which may be embedded and/or removable, may include, for example, read-only memory, flash memory, magnetic storage devices, for example, hard disks, floppy disk drives, magnetic tape, optical disc drives and/or media, non-volatile random access memory (NVRAM), and/or the like. Like volatile memory  40 , non-volatile memory  42  may include a cache area for temporary storage of data. At least part of the volatile and/or non-volatile memory may be embedded in processor  20 . The memories may store one or more software programs, instructions, pieces of information, data, and/or the like which may be used by the apparatus for performing operations disclosed herein including process  300  and/or the like. Alternatively or additionally, the apparatus may be configured to cause the operations disclosed herein with respect to the base stations/WLAN access points and network nodes including the UEs. 
     The memories may comprise an identifier, such as an international mobile equipment identification (IMEI) code, capable of uniquely identifying apparatus  10 . The memories may comprise an identifier, such as an international mobile equipment identification (IMEI) code, capable of uniquely identifying apparatus  10 . In the example embodiment, the processor  20  may be configured using computer code stored at memory  40  and/or  42  to the provide operations disclosed herein with respect to the base stations/WLAN access points and network nodes including the UEs including process  300  and/or the like. 
     Some of the embodiments disclosed herein may be implemented in software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and/or hardware may reside on memory  40 , the control apparatus  20 , or electronic components, for example. In some example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a “computer-readable medium” may be any non-transitory media that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer or data processor circuitry, with examples depicted at  FIG. 4 , computer-readable medium may comprise a non-transitory computer-readable storage medium that may be any media that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. 
     The following provides some additional description related to beam sweeping in the 5G New Radio. The UE may obtain time and frequency synchronization to a cell (and obtains the Cell-ID) through detecting SS/PBCH blocks (SSB). The SSB may contain the Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS) and Primary Broadcast Channel (PBCH) together with Demodulation Reference Signals (DMRS) associated to PBCH (see, e.g., TS 38.213, section 4.1). The PSS and SSS may carry the Cell-ID via sequence initialization, and PBCH may carry Master Information Block (MIB) including DMRS, SSB index, and/or the like. To support beam forming, the SSB can be sent to different spatial direction in a time multiplexed manner. Candidate locations in a half-frame (5 ms) are illustrated in  FIG. 5  for a certain use case at 30 kHz (see, e.g., Case B at TS 38.213]. 
     The pattern of SSBs sent in the half-frame pattern is repeated with a certain period (e.g., 5, 10, 20, 40, 80, or 160 ms). Correspondingly, for System Information Block  1  (SIB1), the UE is configured via MIB (‘pdcch-ConfigSIB1’) with monitoring pattern for Type0-PDCCH, scheduling the SIB1. This configuration gives the UE the length of the Control Resource Set (CORESET) in terms of symbols {e.g., 1, 2, or 3}, number of contiguous resource blocks (e.g., 24, 48, or 96}, frequency location of the CORESET (in relation to the SSB location), and the used pattern and parametrization for the monitoring pattern. For example for SS/PBCH and CORESET monitoring pattern 1 where monitoring occasion occurs every 20 ms, the UE may be given an offset (O) from the start of the radio frame (where occasions occur), with a shift (M) placing the monitoring occasion corresponding each SSB in time, together with the number of possible monitoring occasions per slot. Based on the detected SSB index and information provided by MIB, the UE may determine the monitoring occasion (search space) corresponding to each SSB index.  FIG. 6  illustrates one realization of search space locations. 
     Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein may be enhanced usage of bidirectional slots. 
     The subject matter described herein may be embodied in systems, apparatus, methods, and/or articles depending on the desired configuration. For example, the base stations and user equipment (or one or more components therein) and/or the processes described herein can be implemented using one or more of the following: a processor executing program code, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), an embedded processor, a field programmable gate array (FPGA), and/or combinations thereof. These various implementations may include implementation in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device. These computer programs (also known as programs, software, software applications, applications, components, program code, or code) include machine instructions for a programmable processor, and may be implemented in a high-level procedural and/or object-oriented programming language, and/or in assembly/machine language. As used herein, the term “computer-readable medium” refers to any computer program product, machine-readable medium, computer-readable storage medium, apparatus and/or device (for example, magnetic discs, optical disks, memory, Programmable Logic Devices (PLDs)) used to provide machine instructions and/or data to a programmable processor, including a machine-readable medium that receives machine instructions. Similarly, systems are also described herein that may include a processor and a memory coupled to the processor. The memory may include one or more programs that cause the processor to perform one or more of the operations described herein. 
     Although a few variations have been described in detail above, other modifications or additions are possible. In particular, further features and/or variations may be provided in addition to those set forth herein. Moreover, the implementations described above may be directed to various combinations and subcombinations of the disclosed features and/or combinations and subcombinations of several further features disclosed above. Other embodiments may be within the scope of the following claims. 
     If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described functions may be optional or may be combined. Although various aspects of some of the embodiments are set out in the independent claims, other aspects of some of the embodiments comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims. It is also noted herein that while the above describes example embodiments, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications that may be made without departing from the scope of some of the embodiments as defined in the appended claims. Other embodiments may be within the scope of the following claims. The term “based on” includes “based on at least.” The use of the phase “such as” means “such as for example” unless otherwise indicated.