Apparatus and method for communicating synchronization signal / physical broadcast channel block transmission requests in a wireless communication system

Abstract

Various aspects of the present disclosure relate to methods, apparatuses, and devices for wireless communication. A user equipment (UE) may generate (1002) a request for at least one transmission of at least one synchronization signal (SS) / physical broadcast channel (PBCH) block based at least in part on a condition. The UE may also transmit (1004), to a first serving cell, a random access preamble, wherein the random access preamble indicates the request for the at least one transmission of the at least one SS / PBCH block associated with a second serving cell.

Description

APPARATUS AND METHOD FOR COMMUNICATING SYNCHRONIZATIONSIGNAL / PHYSICAL BROADCAST CHANNEL BLOCK TRANSMISSION REQUESTS IN A WIRELESS COMMUNICATION SYSTEMTECHNICAL FIELD

[0001] The present disclosure relates to wireless communications, and more specifically to configuring a synchronization signal (SS)Zphysical broadcast channel (PBCH) block transmission requests in a wireless communication system.BACKGROUND

[0002] A wireless communications system may include one or multiple network communication devices, such as base stations, which may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE), or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like). Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G)).SUMMARY

[0003] An article “a” before an element is unrestricted and understood to refer to “at least one” of those elements or “one or more” of those elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” may be interchangeable. As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of’ or “one or more of’ or “one or both of’) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A”may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” Further, as used herein, including in the claims, a “set” may include one or more elements.

[0004] Various aspects of the present disclosure relate to wireless communications, including improved methods and apparatuses that support requests for SS / PBCH block transmissions in a wireless communication system. A UE may generate a request for at least one transmission of at least one SS / PBCH block based at least in part on a condition and transmit, to a first serving cell, a random access preamble, wherein the random access preamble indicates the request for the at least one transmission of the at least one SS / PBCH block associated with a second serving cell. The UE may transmit the random access preamble during a random access procedure.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 illustrates an example of a wireless communications system in accordance with aspects of the present disclosure.

[0006] Figure 2 illustrates an example of a RACH procedure in accordance with aspects of the present disclosure.

[0007] Figure 3 illustrates an example of a time and frequency structure of a SS / PBCH block in accordance with aspects of the present disclosure.

[0008] Figure 4 illustrates an example of a procedure for master information block (MIB) and / or system information block (SIB) transmission flow in accordance with aspects of the present disclosure.

[0009] Figure 5 illustrates an example of a procedure for synchronization signal block (SSB)-based radio resource management (RRM) measurement timing configuration (SMTC) communications in accordance with aspects of the present disclosure.

[0010] Figure 6 illustrates an example of a structure of a synchronization signal block (SSB) request medium access control (MAC) control element (CE) (MAC CE) in accordance with aspects of the present disclosure.

[0011] Figure 7 illustrates an example of a UE in accordance with aspects of the present disclosure.

[0012] Figure 8 illustrates an example of a processor in accordance with aspects of the present disclosure.

[0013] Figure 9 illustrates an example of a network equipment (NE) in accordance with aspects of the present disclosure.

[0014] Figure 10 illustrates a flowchart of a method performed by a UE in accordance with aspects of the present disclosure.

[0015] Figure 11 illustrates a flowchart of a method performed by a NE in accordance with aspects of the present disclosure.DETAILED DESCRIPTION

[0016] Various aspects of the present disclosure relate to transmitting and / or receiving a request for SS / PBCH block transmissions a wireless communication system. The SS / PBCH block transmissions may be requested on one serving cell, but may be for transmission of the SS / PBCH block on another serving cell. The request may be transmitted from one device (e.g., UE), and the request may be received by another device (e.g., NE). However, in some cases, excessive data may be used for transmitting system information (e.g., SSBs, PBCH, SIB1), for example, the system information may be transmitted on a regular basis using excessive data, power, and other resources.

[0017] By reducing one or more of the times that the system information is transmitted, there may be a reduction in power consumption, processor usage, and data usage, and there may be an increase in overall system performance.

[0018] Aspects of the present disclosure are described in the context of a wireless communications system.

[0019] Figure 1 illustrates an example of a wireless communications system 100 in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more NE 102, one or more UE 104, and a core network (CN) 106. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE-Advanced (LTE-A) network. Insome other implementations, the wireless communications system 100 may be a new radio (NR) network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultrawideband (5G-UWB) network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc.

[0020] The one or more NE 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the NE 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN), a NodeB, an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface.

[0021] An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN). In some implementations, different geographic coverage areas associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with different NE 102.

[0022] The one or more UE 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. Insome implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Intemet-of-Things (loT) device, an Intemet-of-Everything (loE) device, or machine-type communication (MTC) device, among other examples.

[0023] A UE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a UE-to-UE interface (PC5 interface).

[0024] An NE 102 may support communications with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with other NE 102 or the CN 106 through one or more backhaul links (e.g., SI, N2, N2, or network interface). In some implementations, the NE 102 may communicate with each other directly. In some other implementations, the NE 102 may communicate with each other or indirectly (e.g., via the CN 106. In some implementations, one or more NE 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission -reception points (TRPs).

[0025] The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC), or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management functions (AMF)) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers,signal bearers, etc.) for the one or more UEs 104 served by the one or more NE 102 associated with the CN 106.

[0026] The CN 106 may communicate with a packet data network over one or more backhaul links (e.g., via an SI, N2, N2, or another network interface). The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server using the established session (e.g., the established PDU session). The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g., one or more network functions of the CN 106).

[0027] In the wireless communications system 100, the NEs 102 and the UEs 104 may use resources of the wireless communications system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communications). In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures). The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies.

[0028] One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., i=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., ^=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., i=l) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., ^=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., ju=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclicprefix. A fifth numerology (e.g., ^=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0029] A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames). Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

[0030] Additionally or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communications system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., / r=0, ju=l, ,11=2. [1=3, =4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g., quantity) of symbols (e.g., orthogonal frequency division multiplexing (OFDM) symbols). In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing), a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g., i=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

[0031] In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz - 7.125 GHz), FR2 (24.25 GHz -52.6 GHz), FR3 (7.125 GHz - 24.25 GHz), FR4 (52.6 GHz - 114.25 GHz), FR4a or FR4-1 (52.6 GHz - 71 GHz), and FR5 (114.25 GHz - 300 GHz). In some implementations, the NEs 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data). In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

[0032] FR1 may be associated with one or multiple numerologies (e.g., at least three numerologies). For example, FR1 may be associated with a first numerology (e.g., ^=0), which includes 15 kHz subcarrier spacing; a second numerology (e.g., ^=1), which includes 30 kHz subcarrier spacing; and a third numerology (e.g., i=2), which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies). For example, FR2 may be associated with a third numerology (e.g., ^=2), which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., i=3), which includes 120 kHz subcarrier spacing.

[0033] In some systems, a network may expend substantial energy in transmitting synchronization signal blocks (SSBs), physical broadcast channels (PBCHs) (e.g., containing a master information block (MIB) and / or a system information block (SIB) 1 (SIB1)). The SIBs apart from SIB1 may be provided on demand. It may be desirable to save energy with respect to SSBs and SIB1. In one example, these may be provided on a need basis (e.g., on on-demand basis). In another example, an anchor cell may be used as a proxy (e.g., for time-frequency synchronization, SIB1) for these.

[0034] In certain systems, for network energy savings, procedures and / or signaling methods may be used to support on-demand SSB secondary cell (SCell) operation for UEs in a connected mode configured with carrier aggregation (CA), for both intra-band and inter-band CA. Such systems may specify triggering methods (e.g., select from a UE uplink wake-up-signal using an existing signal and / or channel, a cell on / off indication via backhaul, Scell activation and / or deactivation signaling, and so forth). Different examples to establish signaling for a UE operating in CA to send a request for an on-demand SSB transmission on an SCell are described herein.

[0035] Emissions and energy consumption from different elements of a telecommunication system may adversely contribute to the climate. Further, the operating expenses to run a telecommunication service may be large. In telecom systems, a number of industry-specific factors rooted in countering rising network costs may shape efficiency efforts. There is a continued rise in mobile data traffic, estimated at 6.4 GB per user per month in 2019 and forecast to grow threefold on a per-user basis over the next five years. With the rise in mobile data traffic combined with the rising costs of the spectrum, capital investment, and ongoing radio access network (RAN) maintenance / upgrades, energy-saving measures in network operations may be necessary. 5G new radio (NR) may offer significant energy-efficiency improvements per gigabyte over previous generations of mobility. However, new 5G use cases and the adoption of mm Wave may require more sites and antennas. This may lead to a more efficient network that may paradoxically result in higher emissions without active intervention.

[0036] Network energy saving may be important for environmental sustainability, to reduce environmental impact (e.g., greenhouse gas emissions), and for operational cost savings. As 5G is becoming pervasive across industries and geographical areas, handling more advanced services and applications may require very high data rates (e.g., extended reality (XR)), networks may be denser, use more antennas, have larger bandwidths, and use more frequency bands. The environmental impact of 5G may need to be controlled, and network energy savings may need to be used.

[0037] In some configurations, the energy cost on mobile networks accounts for -23% of the total operator cost. Most of the energy consumption may come from a radio access network and, in particular, from an active antenna unit (AAU), with data centers and fiber transport accounting for a smaller share. The power consumption of radio access may be split into two parts: the dynamic part which is only consumed when data transmission and / or reception is ongoing, and the static part which is consumed all the time to maintain necessary operation of the radio access devices even when the data transmission and / or reception is not on -going.

[0038] Therefore, a network energy consumption model may be used for a base station, key performance indicators (KPIs), an evaluation methodology, and to identify and study network energy savings techniques in targeted deployment scenarios.Moreover, efficient operation may be determined dynamically and / or semi-statically and finer granularity adaptation of transmissions and / or receptions in one or more of network energy saving techniques in time, frequency, spatial, and power domains, with potential support / feedback from a UE, potential UE assistance information, and information exchange / coordination over network interfaces.

[0039] In various systems, potential network energy consumption gains may be monitored and / or optimized, but also impact on network and user performance may be assessed and / or balanced (e.g., by looking at KPIs such as spectral efficiency, capacity, user perceived throughput (UPT), latency, UE power consumption, complexity, handover performance, call drop rate, initial access performance, service level agreement (SLA) assurance related KPIs, etc.).

[0040] In certain systems, there may be several different types of RACH processes and different use cases where different procedures are used. For example, for RACH for non-standalone (NSA) setup, [A]+[C]+[D] may be applicable. For contention based RACH in standalone (SA) setup, [A]+[B]+[C]+[D] may be applicable.

[0041] Figure 2 illustrates an example of a RACH procedure 200 in accordance with aspects of the present disclosure. In some implementations, the RACH procedure 200 may implement, or be implemented by, aspects of the wireless communication system 100 as described with reference to Figure 1. The RACH procedure 200 may include a UE 202 which may be an example of a UE 104 as described herein. The RACH procedure 200 may also include a gNB 204 which may be an example of a NE 102 as described herein. In the following description of the RACH procedure 200, the operations between the UE 202 and the gNB 204 may be transmitted in a different order than the example order shown, or the operations performed by the UE 202 and the gNB 204 may be performed in different orders or at different times. Some operations may also be omitted from the RACH procedure 200, and other operations may be added to the RACH procedure 200.

[0042] At 206, the gNB 204 may transmit SSB / PBCH to the UE 202.

[0043] At 208, downlink synchronization may occur at the UE 202.

[0044] At 210, the gNB 204 may transmit SIB1 to the UE 202.

[0045] Then, at 212, the UE may decode a control resource set (CORESET) 0 and / or the SIB1.

[0046] At 214, 216, and 218, UL synchronization and / or UL scheduling may occur.

[0047] Specifically, at 214, a first message (Msgl) (e.g., preamble transmission) is transmitted. The UE 202 selects a random access preamble from a set of predefined preambles. These preambles may be selected out of two categories: short preamble and long preamble format. The UE 202 may also select a random sequence number for the preamble. After choosing the preamble and sequence number, the UE 202 transmits the preamble on a physical RACH (PRACH).

[0048] At 216, a second message (Msg2) (e.g., random access response (RAR)) may be transmitted. Upon receiving Msgl, the gNB 204 (e.g., 5G base station) sends a response called Msg2. Msg2 may include several critical pieces of information, such as a time advance (TA) command for timing adjustment, a random access preamble ID (RAPID) matching the preamble sent by the UE 202, and an initial uplink grant for the UE 202. The gNB 204 may also assign a temporary identifier called random access radio network temporary identifier (RA-RNTI) to the UE 202.

[0049] At 218, a third message (Msg3) may be transmitted. Using the initial uplink grant provided in Msg2, the UE 202 transmits Msg3 on a physical uplink shared channel (PUSCH). Msg3 may be a PUSCH which may carry a certain RRC message (e.g., RrcRequest) or may be pure physical (PHY) data.

[0050] At 220, a fourth message (Msg4) (e.g., contention resolution) may be transmitted. After processing Msg3, the gNB 204 may send Msg4 to the UE 202. Msg4 may be MAC data which is for contention resolution. The contention resolution message may contain the UE's identity, confirming that the gNB 204 has correctly identified the UE 202, and contention has been resolved. At this step, the network may provide the UE 202 with cell radio network temporary identifier (C-RNTI).

[0051] In some system, cell search may be a procedure for a UE to acquire time and frequency synchronization with a cell and to detect a physical layer cell identity (ID) (PCI) of the cell. During cell search operations which may be carried out when a UE is powered ON, mobility in connected mode, idle mode mobility (e.g., reselections), inter-RAT mobility to NR system etc., the UE uses NR synchronization signals and PBCH to derive necessary information required to access the cell.

[0052] Similar to LTE, two types of synchronization signals may be defined for NR: primary synchronization signal (PSS) and secondary synchronization signal (SSS). The synchronization signal / physical broadcast channel (PBCH) block (SS / PBCH block) may consist of PSS, SSS, and / or PBCH. Synchronization signals may be used by a UE for reference signal received power (RSRP) and reference signal received quality (RSRQ) measurements.

[0053] In various systems, for a PCI: there may be 1008 unique PCIs defined in 5G NR - double of that in LTE (e.g., 504), 1008 NR PCIs may be divided into 336 unique PCI groups and each group may have three different identities, the PCI of a cell may be calculated using - NIDCell = 3 * NID(l) + NID(2) where NID(l) G {0, 1, ... ,335} and NID(2) G {0,1,2}, and the UE may derive a PCI group number NID(l) from SSS and a physical-layer identity NID(2) from PSS.

[0054] Figure 3 illustrates an example of a time and frequency structure 300 of a SS / PBCH block in accordance with aspects of the present disclosure. The time and frequency structure 300 includes PSS 302, PBCH 304, and SSS 306.

[0055] The PSS 302, the SSS 306, and the PBCH 304 may always be together in consecutive OFDM symbols. Each SS / PBCH block may occupy 4 OFDM symbols in the time domain and spread over 240 subcarriers (e.g., 20 resource blocks (RBs)) in the frequency domain. The PSS 302 may occupy a first OFDM symbol and span 127 subcarriers. The SSS 306 may be located in a third OFDM symbol and may span over 127 subcarriers. There may be 8 unused subcarriers below the SSS 306 and 9 unused subcarriers above the SSS 306. The PBCH 304 may occupy two full OFDM symbols (e.g., second and fourth) spanning 240 subcarriers and in the third OFDM symbol spanning 48 subcarriers below and above the SSS 306. This may result in the PBCH 304 occupying 576 subcarriers across three OFDM symbols (e.g., 240+48+48+240 = 576). The PBCH demodulation reference signal (DM-RS) may occupy 144 resource elements (REs) which is one-fourth of the total REs and the remaining amount of REs for the PBCH payload may be 432 REs (e.g., 576-144 = 432 REs).

[0056] The following may be a summary of frequency resources occupied by a SS / PBCH block: Table 1 summarizes resources within an SS / PBCH block for PSS,SSS, PBCH and DM-RS for PBCH, the complex-valued symbols corresponding to resource elements denoted as 'Set to O' in Table 1 are set to zero, and the location of PBCH DM-RS in Table 1 depends upon PCI (v = NIDcell mod 4) of the cell (PCI already determined by the UE using PSS / SSS).Table 1

[0057] SSB details in a time domain may be: each SS / PBCH block spans across 4OFDM symbols in the time domain, an SS / PBCH block is periodically transmitted with a periodicity of 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms, while longer SS / PBCH block periodicities enhances network energy performance, the shorter periodicities facilitate faster cell search for UEs, and a UE may assume a default periodicity of 20 ms during initial cell search or idle mode mobility.

[0058] To enable beam-sweeping for PSS / SSS and PBCH, SS burst sets may be defined. An SS burst set may include a set of SS / PBCH blocks, where each SS / PBCHblock may be transmited on a different beam. Specifically, an SS burst set may include one or more SS / PBCH blocks, and SS / PBCH blocks in the SS burst set may be transmited in a time-division multiplexing fashion. An SS burst set may be confined to a 5 ms window and may either be located in a first-half or a second-half of a 10 ms radio frame. The network may set a SS / PBCH block periodicity via radio resource control (RRC) parameter ssb-PeriodicityServingCell which may have values in the following range {5ms, 10ms, 20ms, 40ms, 80ms, 160ms}. The maximum number of candidate SS / PBCH blocks (Lmax) within an SS burst set may depend on a carrier frequency / band as shown in Table 2.Table 2

[0059] Within a 5 ms half frame, a starting OFDM symbol index for a candidateSS / PBCH block within the SS burst set may depend upon a subcarrier spacing (SCS) and carrier frequency / band (e.g., as shown in Table 3).Table 3

[0060] When the network is not using beam forming, it may transmit only one SS / PBCH block and there may only be one SS / PBCH block starting position. In one example, a timing of candidate of SS / PBCH blocks within an SS burst set is illustrated in Figure 4 for the case of SCS = 15 kHz and a carrier frequency between 3 GHz and 6 GHz.

[0061] Figure 4 illustrates an example of a procedure 400 for MIB and / or SIB transmission flow in accordance with aspects of the present disclosure. In some implementations, the procedure 400 may implement, or be implemented by, aspects of the wireless communication system 100 as described with reference to Figure 1. Theprocedure 400 may include a UE 402 which may be an example of a UE 104 as described herein. The procedure 400 may also include a gNB 404 which may be an example of a NE 102 as described herein. In the following description of the procedure 400, the operations between the UE 202 and the gNB 204 may be transmitted in a different order than the example order shown, or the operations performed by the UE 202 and the gNB 204 may be performed in different orders or at different times. Some operations may also be omitted from the procedure 400, and other operations may be added to the procedure 400.

[0062] At 406, a MIB is transmitted. At 408, a SIB1 is transmitted. Next, at 410, periodic system information messages are transmitted. At 412, a system information request may be transmitted. Then, at 414, on request system information messages may be transmitted.

[0063] In one example, an MIB may be: transmitted over BCH and / or PBCH - it should be noted that PBCH is transmitted as a part of SSB so it may be beneficial to understand SSB as much as possible, transmitted with the periodicity of 80 ms and within this 80 ms repetitive transmission may happen, for initial cell selection - the UE 402 may assume that half frames with SS / PBCH blocks occur with a periodicity of 2 frames, and / or include parameters that are required to decode SIB1.

[0064] Table 4 shows one example of an MIB.Table 4

[0065] In Table 4, subCarrierSpacingCommon may indicate the SCS for SIB1, Msg2 and / or Msg4 for initial access and system information (Sl)-messages.Interpretation of this value may vary with a frequency range as shown in Table 5.Table 5

[0066] Further, in Table 4, ssb-subcarrierOffset may correspond to k ssb which may indicate a frequency domain offset between SSB and an overall resource block grid in a number of subcarriers. If k ssb requires a value higher than 15, it may be represented by a combination of a PBCH data field and ssb-subcarrierOffset. Moreover, dmrs-TypeA -Position may indicate a position of a first downlink (DL) DM-RS. pdcchConfigSIBl may be used to determine a bandwidth for physical downlink control channel (PDCCH)ZSIB, a common ControlResourceSet (CORESET), a common search space, and necessary PDCCH parameters. This may correspond to RMSI-PDCCH- Config.

[0067] Certain embodiments found herein may define signaling transmitted by a UE to indicate a request for an on-demand SSB transmission by a network. It should be noted that the acronym SSB may be used to refer to an SS / PBCH block herein.

[0068] In the time domain, an SS / PBCH block may include 4 OFDM symbols, numbered in increasing order from 0 to 3 within the SS / PBCH block, where PSS, SSS, and PBCH with associated DM-RS are mapped to symbols.

[0069] In one example, a UE requesting an on-demand SSB transmission on an SCell transmits a RACH preamble (e.g. a PRACH signal), on the PCell or on an active SCell to the network (e.g., to a gNB).

[0070] In another example, a UE selects a RACH preamble from a pool of preambles designated for a non-contention based RACH procedure. In one implementation, the UE selects the RACH preamble from a pool of preamblesconfigured to trigger an on-demand SSB transmission. The pool of preambles may be configured by the network by a UE -specific configuration, and may contain one or more preambles, such as PRACH signals generated based on one or more cyclic shifts or root sequence indexes.

[0071] In another implementation, a RACH preamble is associated with an SCell identifier so that, depending for which SCell a UE intends to request SSB transmission, a preconfigured RACH preamble is transmitted. Specifically, the UE may be configured with the association so that a first RACH preamble is associated with a first SCell (e.g., a first SCell index), a second RACH preamble is associated with a second SCell (e.g., a second SCell index), and so forth. The association may be configured by the network by a UE -specific configuration. Consequently, a network element, such as a gNB receiving the RACH preamble, may identify which SCell the SSB request is intended for.

[0072] In a further implementation (e.g., for a four-step RACH procedure), the UE receives a message from the network (e.g., RACH Msg 2) after transmitting a RACH preamble. The message includes scheduling information for a subsequent uplink transmission (e.g., for a RACH Msg 3). In some implementations, the UE may transmit SSB request assistance information as part of the subsequent uplink transmission. The SSB request assistance information may include one or more of:

[0073] A. An identifier or a flag to indicate that the RACH procedure includes or represents a request for an on-demand SSB transmission. This may be suitable where there is no specific RACH preamble predefined for a non-contention based RACH procedure (e.g. it is a general predefined RACH preamble for a non-contention based RACH procedure) or where a RACH preamble is selected for a contention-based RACH procedure;

[0074] B. At least one SCell identifier (e.g., an SCell index) for which the UE is requesting SSB transmission;

[0075] C. A number of SSB transmissions that is being requested, and optionally a time pattern (e.g., a periodicity or offset between transmissions) if multiple SSB transmissions are being requested;

[0076] D. A start time when the UE is ready to receive the requested SSB transmission;

[0077] E. A time window (e.g., by a start time and an end time, or a start time and a duration) during which the UE is ready to receive the requested SSB transmission;

[0078] F. A periodicity after which the time window repeats. The periodicity may be calculated from either the start or end of the time window;

[0079] G. Whether a full SSB is requested or only part of an SSB (e.g., one or more of the following: PSS, SSS, PBCH, MIB, PBCH DM-RS, and PBCH payload);

[0080] H. The PBCH (e.g., MIB + information conveyed by PBCH DM-RS) configuration (or parts thereof) for the SCell that is available at the UE;

[0081] I. The subcarrier spacing that the UE is requesting for the SSB transmission for an operating band allowing two subcarrier spacings - indicates whether a lower or higher of two subcarrier spacings is requested;

[0082] J. An index of the SSB block being requested; and

[0083] K. Measurement values of the current serving cells for which the UE has received SSB recently (e.g., within a configured time prior to transmission and / or creation of the SSB request.

[0084] In another implementation (e.g., for a two-step RACH procedure), the UE transmits SSB request assistance information as part of a PUSCH transmission accompanying a RACH preamble transmission (e.g., RACH Msg A). The SSB request assistance information may include one or more of:

[0085] A. An identifier or a flag to indicate that the RACH procedure includes or represents a request for an on-demand SSB transmission. This may be suitable where there is no specific RACH preamble predefined for a non-contention based RACH procedure (e.g. it is a general predefined RACH preamble for a non-contention based RACH procedure) or where a RACH preamble is selected for a contention-based RACH procedure;

[0086] B. At least one SCell identifier (e.g., an SCell index) for which the UE is requesting SSB transmission;

[0087] C. A number of SSB transmissions that is being requested, and optionally a time pattern (e.g., a periodicity or offset between transmissions) if multiple SSB transmissions are being requested;

[0088] D. A start time when the UE is ready to receive the requested SSB transmission;

[0089] E. A time window (e.g., by a start time and an end time, or a start time and a duration) during which the UE is ready to receive the requested SSB transmission;

[0090] F. A periodicity after which the time window repeats. The periodicity may be calculated from either the start or end of the time window;

[0091] G. Whether a full SSB is requested or only part of an SSB (e.g., one or more of the following: PSS, SSS, PBCH, MIB, PBCH DM-RS, and PBCH payload);

[0092] H. The PBCH (e.g., MIB + information conveyed by PBCH DM-RS) configuration (or parts thereof) for the SCell that is available at the UE;

[0093] I. The subcarrier spacing that the UE is requesting for the SSB transmission for an operating band allowing two subcarrier spacings - indicates whether a lower or higher of two subcarrier spacings is requested;

[0094] J. An index of the SSB block being requested; and

[0095] K. Measurement values of the current serving cells for which the UE has received SSB recently (e.g., within a configured time prior to transmission and / or creation of the SSB request.

[0096] In one example of a random access procedure, MsgA-PUSCH is transmitted after a PRACH. For a Type-2 RACH, a UE may transmit a PUSCH, when applicable, after transmitting a PRACH. The UE may encode a transport block provided for the PUSCH transmission using redundancy version number 0. The PUSCH transmission may be after the PRACH transmission by at least N symbols where N = 2 for . = 0 ori = 1, IV = 4 for i = 2 or i = 3, IV = 16 for i = 5, IV = 32 for i = 6, and i is the SCS configuration for the active uplink (UL) bandwidth part (BWP).

[0097] A UE may not transmit a PUSCH in a PUSCH occasion if the PUSCH occasion associated with a DM-RS resource is not mapped to a preamble of valid PRACH occasions or if the associated PRACH preamble is not transmitted. A UE may transmit a PRACH preamble in a valid PRACH occasion if the PRACH preamble is not mapped to a valid PUSCH occasion. Moreover, a mapping between one or multiplePRACH preambles and a PUSCH occasion associated with a DM-RS resource may be per PUSCH configuration provided by MsgA-PUSCH-Re source.

[0098] A UE may determine time resources and frequency resources for PUSCH occasions in an active UE BWP from msgA-PUSCH-Config or separateMsgA-PUSCH- Config for the active UL BWP. If the active UL BWP is not the initial UL BWP and msgA-PUSCH-Config or separateMsgA-PUSCH-Config is not provided for the active UL BWP, the UE may use the msgA-PUSCH-Config or separateMsgA-PUSCH-Config provided for the initial UL BWP.

[0099] In one implementation, a UE may determine whether it requires MIB information based on whether a timer has expired, or a gNB may determine whether it needs to transmit MIB information based on whether a timer has expired. The timer may be exemplarily of a MIBExpirationTimer and may resemble a duration for which a UE may assume that the information in MIB hasn’t changed since the latest reception of MIB for the serving cell, or may resemble a duration for which a gNB may assume that the UE’s information derived from MIB hasn’t changed since the latest transmission of MIB for the serving cell. Upon successful reception of a MIB, the UE may reset a timer to an initial value; upon transmission of a MIB, the gNB may reset a timer to an initial value. The initial value may be predefined by a specification or may be configurable by a network element. The initial value may be chosen from a set of multiples of a MIB (or generally, SSB) periodicity. For example, in 5G NR, the periodicity of SSB transmissions may be set to one of the following values {5ms, 10ms, 20ms, 40ms, 80ms, 160ms} by RRC parameter ssb-PeriodicityServingCell, so the initial value may be set to a multiple of one or more of these values.

[0100] In another implementation, a UE indicates a request for at least MIB if the last acquisition time of MIB for the SCell is longer than a preconfigured time, such as 80 ms. The preconfigured value may be selected the same way as an initial value for a time-based implementation (e.g., from a set of multiples of a MIB (or generally, SSB) periodicity such as multiples of one of the following values {5ms, 10ms, 20ms, 40ms, 80ms, 160ms} in 5G NR).

[0101] In another example, a UE requesting an on-demand SSB transmission on an SCell transmits a SSB request medium access control (MAC) control element (CE) (MAC CE) on a PCell or on an active SCell to the network (e.g., to a gNB).

[0102] In one implementation, the MAC CE indicates the request with a specific LCID (e.g., as part in a corresponding MAC subheader associated with the MAC CE). In another implementation, the UE may include SSB request assistance information as part of an SSB request MAC CE. The SSB request assistance information may include one or more of the following:

[0103] A. At least one SCell identifier (e.g., an SCell index) for which the UE is requesting SSB transmission;

[0104] B. A number of SSB transmissions that are being requested, and optionally a time pattern (e.g., a periodicity or offset between transmissions) if multiple SSB transmissions being requested;

[0105] C. A start time when the UE is ready to receive the requested SSB transmission;

[0106] D. A time window (e.g., by a start time and an end time, or a start time and a duration) during which the UE is ready to receive the requested SSB transmission;

[0107] E. A periodicity after which the time window repeats. The periodicity may be calculated from either the start or end of the time window;

[0108] F. Whether a full SSB is requested or only part of the SSB (e.g., one or more of PSS, SSS, PBCH, MIB, PBCH associated DM-RS, PBCH payload);

[0109] G. The PBCH (e.g., MIB + information conveyed by PBCH DM-RS) configuration (or parts thereof) for the SCell that is available at the UE;

[0110] H. The subcarrier spacing that the UE is requesting for the SSB transmission for an operating band allowing two subcarrier spacings which indicates whether a lower or higher of the two subcarrier spacings is requested;

[0111] I. An index of the SSB block being requested; and

[0112] J. Measurement values of current serving cells for which the UE has received SSB recently (e.g., within a configured time prior to transmission and / or creation of the SSB request).

[0113] In one implementation, a UE may determine whether it requires MIB information based on whether a timer has expired, or a gNB may determine whether itneeds to transmit MIB information based on whether a timer has expired. The timer may be exemplarily of a MIBExpirationTimer and may resemble a duration for which a UE may assume that the information in MIB hasn’t changed since the latest reception of MIB for the serving cell, or may resemble a duration for which a gNB may assume that the UE’s information derived from MIB hasn’t changed since the latest transmission of MIB for the serving cell. Upon successful reception of a MIB, the UE may reset a timer to an initial value; upon transmission of a MIB, the gNB may reset a timer to an initial value. The initial value may be predefined by a specification or may be configurable by a network element. The initial value may be chosen from a set of multiples of a MIB (or generally, SSB) periodicity. For example, in 5G NR, the periodicity of SSB transmissions may be set to one of the following values {5ms, 10ms, 20ms, 40ms, 80ms, 160ms} by RRC parameter ssb-PeriodicityServingCell, so the initial value may be set to a multiple of one or more of these values.

[0114] In another implementation, a UE may indicate a request for at least MIB if the last acquisition time of MIB for the SCell is longer than a preconfigured time, such as 80 ms. The preconfigured value may be selected the same way as the initial value for a time-based implementation (e.g., from a set of multiples of a MIB (or generally, SSB) periodicity (e.g., multiples of one of the following values {5ms, 10ms, 20ms, 40ms, 80ms, 160ms} in 5G NR).

[0115] In a further implementation, the start time and duration may be requested and configured as SSB-based RRM measurement timing configuration (SMTC) patterns with the following parameters:

[0116] A. Periodicity and offset of a measurement window in which to receive SS / PBCH blocks. Periodicity and offset may be given as a number of subframes;

[0117] B. List of cells (e.g., physical cell identity or just cell indexes of the concerned serving cells configured at the UE);

[0118] C. Duration of the measurement window in which to receive SS / PBCH blocks. It may be given as a number of subframes; and / or

[0119] D. Which SSB to measure (e.g., using a BITMAP to represent each SSB by its index). This may be indicated only if the UE has information about which SSB may be good for the UE based on a previous configuration and / or previous measurements.

[0120] As shown in Figure 5, the UE may request SSB transmission to enable configuration measurement timing configurations (e.g., timing occasions at which the UE proposes to measure SSBs). The network may accept the same configuration as requested by the UE, or may use different values depending on an overall situation (e.g., how many UEs need SSB transmission).

[0121] Figure 5 illustrates an example of a procedure 500 for SMTC communications in accordance with aspects of the present disclosure. In some implementations, the procedure 500 may implement, or be implemented by, aspects of the wireless communication system 100 as described with reference to Figure 1. The procedure 500 may include a UE 502 which may be an example of a UE 104 as described herein. The procedure 500 may also include a gNB 504 which may be an example of a NE 102 as described herein. In the following description of the procedure 500, the operations between the UE 502 and the gNB 504 may be transmitted in a different order than the example order shown, or the operations performed by the UE 502 and the gNB 504 may be performed in different orders or at different times. Some operations may also be omitted from the procedure 500, and other operations may be added to the procedure 500.

[0122] At 506, the UE 502 may request SMTC. Then, at 508, the gNB 504 may transmit SMTC.

[0123] In one implementation, a priority of an SSB request MAC CE for logical channel prioritization may be higher than a priority of one or more of the following:

[0124] A. A MAC CE for extended pre-emptive buffer status report (BSR);

[0125] B. A MAC CE for SL-BSR, with exception of prioritized SL-BSR and SL-BSR included for padding;

[0126] C. MAC CE for integrated access and backhaul (lAB)-mobile terminal (MT) a recommended beam indication, MAC CE for a desired IAB-MT power spectral density (PSD) range, or a MAC CE for a desired DL Tx power adjustment;

[0127] D. Data from any logical channel, except data from UL-CCCH;

[0128] F. A MAC CE for a recommended bit rate query;

[0129] G. A MAC CE for BSR included for padding; and / or

[0130] H. A MAC CE for SL-BSR included for padding.

[0131] In another implementation, a priority of an SSB request MAC CE for logical channel prioritization may be lower than a priority of one or more of the following:

[0132] A. A MAC CE for C-RNTI, or data from UL-CCCH;

[0133] B. A MAC CE for enhanced beam failure recovery (BFR), a MAC CE for configured grant confirmation, or a MAC CE for a multiple entry configured grant confirmation;

[0134] C. A MAC CE for a sidelink configured grant confirmation;

[0135] D. A MAC CE for listen-before-talk (LBT) failure;

[0136] E. A MAC CE for a timing advance report;

[0137] F. A MAC CE for a prioritized SL-BSR prioritized;

[0138] G. A MAC CE for an extended BSR, with the exception of BSR included for padding;

[0139] H. A MAC CE for an enhanced single entry power headroom report (PHR), or a MAC CE for enhanced multiple entry PHR; and / or

[0140] I. A MAC CE for a positioning measurement gap activation and / or deactivation request.

[0141] In a further implementation, generation of a SSB request MAC CE may trigger a scheduling request (SR) or RACH procedure. In another implementation, a new SSB request MAC CE may be associated with a SR configuration. An SR configuration may include a set of physical uplink control channel (PUCCH) resources for the SR across different BWPs and cells. In one example, at most one PUCCH resource for SR is configured per BWP for the SSB request MAC CE. In another example, a dedicated SR configuration is configured for the SSB request MAC CE. In a further implementation, the SR configuration for a SSB request MAC CE may correspond to one or more logical channels.

[0142] In some implementations, a SR triggered for a SSB request MAC CE may be cancelled if the corresponding SSB request has been cancelled. In otherimplementations, an SR triggered for an SSB request may be cancelled if a MAC PDU is transmitted and this PDU includes an SSB request MAC CE.

[0143] In various implementations, an SSB request MAC CE may correspond to a specific MAC subheader. The MAC CE may have a fixed or variable size. In one example having a variable size, it may include one or more of the following fields:

[0144] A. F: This field may indicate the presence of the octet containing an SCell index field and the presence of the octets containing Ci fields. If the F field is set to 1, the octet containing SCell index field may be present and the octets containing Ci fields may not be present. If the F field is set to 1, the octet containing the SCell index field may not be present and the octets containing Ci fields may be present;

[0145] B. SCell index: This field may indicate the identity of the SCelllndex i for which the UE requests an SSB transmission. The length of the field may be 5 bits;

[0146] C. Ci: If there is an SCell configured for the MAC entity with SCelllndex i, this field may indicate whether SSB is requested for SCell with SCelllndex i. The Ci field may be set to 1 to indicate that SSB for the SCell with SCelllndex i is requested. The Ci field may be set to 0 to indicate that SSB for the SCell with SCelllndex i is not requested;

[0147] D. TX: This field indicates how many SSB transmissions the UE is requesting. The length of the field may be 3 bits;

[0148] E. MU: This field may indicate, for operating bands supporting two subcarrier spacings, whether the lower or higher of the subcarrier spacings is requested. The MU field may be set to 0 to indicate the lower of the two supported subcarrier spacings is requested. The MU field may be set to 1 to indicate the higher of the two supported subcarrier spacings is requested. For operating bands allowing only one subcarrier spacings the MAC entity may ignore the MU field;

[0149] F. SSB block ID: This field may indicate an index of the SSB that the UE requests. If this field is set to 0, then no specific beam is requested. The length of the field may be 6 bits;

[0150] G. B: This field may indicate the SSB content that is being requested. The field may be set to 0 to indicate that only PSS and / or SSS is requested. The field may be set to 1 to indicate that PSS, SSS, PBCH, and associated DM-RS are requested;

[0151] H. Start: This field may indicate a SFN for the earliest frame when the UE is ready to receive the requested SSB transmission. The length of the field may be 10 bits;

[0152] I. Duration: This field may indicate for how many subframes the UE is ready to receive the requested SSB transmission. The length of the field may be 2 bits; and / or

[0153] J. R: A reserved bit that may be set to 0.

[0154] Figure 6 illustrates an example of a structure of an SSB request MAC CE 600 in accordance with aspects of the present disclosure.

[0155] Figure 7 illustrates an example of a UE 700 in accordance with aspects of the present disclosure. The UE 700 may include a processor 702, a memory 704, a controller 706, and a transceiver 708. The processor 702, the memory 704, the controller 706, or the transceiver 708, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0156] The processor 702, the memory 704, the controller 706, or the transceiver 708, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0157] The processor 702 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, a field programmable gate array (FPGA), or any combination thereof). In some implementations, the processor 702 may be configured to operate the memory 704. In some other implementations, the memory 704 may be integrated into the processor 702. The processor 702 may be configured to execute computer-readable instructions stored in the memory 704 to cause the UE 700 to perform various functions of the present disclosure.

[0158] The memory 704 may include volatile or non-volatile memory. The memory 704 may store computer-readable, computer-executable code including instructions when executed by the processor 702 cause the UE 700 to perform various functionsdescribed herein. The code may be stored in a non-transitory computer-readable medium such the memory 704 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0159] In some implementations, the processor 702 and the memory 704 coupled with the processor 702 may be configured to cause the UE 700 to perform one or more of the functions described herein (e.g., executing, by the processor 702, instructions stored in the memory 704). For example, the processor 702 may support wireless communication at the UE 700 in accordance with examples as disclosed herein. For example, the processor 702 coupled with the memory 704 may be configured to cause the UE 700 to generate a request for at least one transmission of at least one SS / PBCH block based at least in part on a condition. In some examples, the processor 702 coupled with the memory 704 may be configured to cause the UE 700 to transmit, to a first serving cell, a random access preamble, wherein the random access preamble indicates the request for the at least one transmission of the at least one SS / PBCH block associated with a second serving cell. The UE may transmit the random access preamble during a random access procedure.

[0160] The controller 706 may manage input and output signals for the UE 700. The controller 706 may also manage peripherals not integrated into the UE 700. In some implementations, the controller 706 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 706 may be implemented as part of the processor 702.

[0161] In some implementations, the UE 700 may include at least one transceiver 708. In some other implementations, the UE 700 may have more than one transceiver 708. The transceiver 708 may represent a wireless transceiver. The transceiver 708 may include one or more receiver chains 710, one or more transmitter chains 712, or a combination thereof.

[0162] A receiver chain 710 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 710 may include one or more antennas for receiving the signal over the air or wirelessmedium. The receiver chain 710 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiver chain 710 may include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 710 may include at least one decoder for decoding and processing the demodulated signal to receive the transmitted data.

[0163] A transmitter chain 712 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 712 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmitter chain 712 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 712 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0164] Figure 8 illustrates an example of a processor 800 in accordance with aspects of the present disclosure. The processor 800 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 800 may include a controller 802 configured to perform various operations in accordance with examples as described herein. The processor 800 may optionally include at least one memory 804, which may be, for example, an L1 / L2 / L3 cache. Additionally, or alternatively, the processor 800 may optionally include one or more arithmetic -logic units (ALUs) 806. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0165] The processor 800 may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or morecaches (e.g., memory local to or included in the processor chipset (e.g., the processor 800) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM), and others).

[0166] The controller 802 may be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 800 to cause the processor 800 to support various operations in accordance with examples as described herein. For example, the controller 802 may operate as a control unit of the processor 800, generating control signals that manage the operation of various components of the processor 800. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

[0167] The controller 802 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from the memory 804 and determine subsequent instruction(s) to be executed to cause the processor 800 to support various operations in accordance with examples as described herein. The controller 802 may be configured to track memory address of instructions associated with the memory 804. The controller 802 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 802 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 800 to cause the processor 800 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 802 may be configured to manage flow of data within the processor 800. The controller 802 may be configured to control transfer of data between registers, arithmetic logic units (ALUs), and other functional units of the processor 800.

[0168] The memory 804 may include one or more caches (e.g., memory local to or included in the processor 800 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 804 may reside within or on a processor chipset (e.g., local to the processor 800). In some otherimplementations, the memory 804 may reside external to the processor chipset (e.g., remote to the processor 800).

[0169] The memory 804 may store computer-readable, computer-executable code including instructions that, when executed by the processor 800, cause the processor 800 to perform various functions described herein. The code may be stored in a non- transitory computer-readable medium such as system memory or another type of memory. The controller 802 and / or the processor 800 may be configured to execute computer-readable instructions stored in the memory 804 to cause the processor 800 to perform various functions. For example, the processor 800 and / or the controller 802 may be coupled with or to the memory 804, the processor 800, the controller 802, and the memory 804 may be configured to perform various functions described herein. In some examples, the processor 800 may include multiple processors and the memory 804 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

[0170] The one or more ALUs 806 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 806 may reside within or on a processor chipset (e.g., the processor 800). In some other implementations, the one or more ALUs 806 may reside external to the processor chipset (e.g., the processor 800). One or more ALUs 806 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 806 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 806 be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 806 may support logical operations such as AND, OR, exclusive-OR (XOR), not-OR (NOR), and not-AND (NAND), enabling the one or more ALUs 806 to handle conditional operations, comparisons, and bitwise operations.

[0171] The processor 800 may support wireless communication in accordance with examples as disclosed herein. The processor 800 may be configured to or operable to support a means for: generating a request for at least one transmission of at least oneSS / PBCH block based at least in part on a condition, and transmitting, to a first serving cell, a random access preamble, wherein the random access preamble indicates the request for the at least one transmission of the at least one SS / PBCH block associated with a second serving cell. The processor 800 may be configured to transmit the random access preamble during a random access procedure.

[0172] Figure 9 illustrates an example of a NE 900 in accordance with aspects of the present disclosure. The NE 900 may include a processor 902, a memory 904, a controller 906, and a transceiver 908. The processor 902, the memory 904, the controller 906, or the transceiver 908, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0173] The processor 902, the memory 904, the controller 906, or the transceiver 908, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0174] The processor 902 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof). In some implementations, the processor 902 may be configured to operate the memory 904. In some other implementations, the memory 904 may be integrated into the processor 902. The processor 902 may be configured to execute computer-readable instructions stored in the memory 904 to cause the NE 900 to perform various functions of the present disclosure. For example, the processor 902 coupled with the memory 904 may be configured to cause the NE 900 to: receive, at a first serving cell, a random access preamble, wherein the random access preamble indicates a request for at least one transmission of at least one synchronization signal (SS)Zphysical broadcast channel (PBCH) block associated with a second serving cell. The processor 902 may be configured to receive the random access preamble during a random access procedure.

[0175] The memory 904 may include volatile or non-volatile memory. The memory 904 may store computer-readable, computer-executable code including instructions when executed by the processor 902 cause the NE 900 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such the memory 904 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0176] In some implementations, the processor 902 and the memory 904 coupled with the processor 902 may be configured to cause the NE 900 to perform one or more of the functions described herein (e.g., executing, by the processor 902, instructions stored in the memory 904). For example, the processor 902 may support wireless communication at the NE 900 in accordance with examples as disclosed herein.

[0177] The controller 906 may manage input and output signals for the NE 900. The controller 906 may also manage peripherals not integrated into the NE 900. In some implementations, the controller 906 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 906 may be implemented as part of the processor 902.

[0178] In some implementations, the NE 900 may include at least one transceiver 908. In some other implementations, the NE 900 may have more than one transceiver 908. The transceiver 908 may represent a wireless transceiver. The transceiver 908 may include one or more receiver chains 910, one or more transmitter chains 912, or a combination thereof.

[0179] A receiver chain 910 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 910 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 910 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiver chain 910 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmissionof the signal. The receiver chain 910 may include at least one decoder for decoding the processing the demodulated signal to receive the transmitted data.

[0180] A transmitter chain 912 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 912 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmitter chain 912 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 912 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0181] Figure 10 illustrates a flowchart of a method 1000 in accordance with aspects of the present disclosure. The operations of the method 1000 may be implemented by a UE as described herein. In some implementations, a UE 700 may execute a set of instructions to control the function elements of a processor to perform the described functions.

[0182] At 1002, the method may include generating a request for at least one transmission of at least one SS / PBCH block based at least in part on a condition. The operations of 1002 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1002 may be performed by a UE as described with reference to Figure 7.

[0183] At 1004, the method may include transmitting, to a first serving cell, a random access preamble, wherein the random access preamble indicates the request for the at least one transmission of the at least one SS / PBCH block associated with a second serving cell. The random access preamble may be transmitted during a random access procedure. The operations of 1004 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1004 may be performed by a UE as described with reference to Figure 7.

[0184] Figure 11 illustrates a flowchart of another method 1100 in accordance with aspects of the present disclosure. The operations of the method 1100 may beimplemented by a NE as described herein. In some implementations, aNE 900 may execute a set of instructions to control the function elements of a processor to perform the described functions.

[0185] At 1102, the method may include receiving, at a first serving cell, a random access preamble, wherein the random access preamble indicates a request for at least one transmission of at least one SS / PBCH block associated with a second serving cell. The random access preamble may be received during a random access procedure. The operations of 1102 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1102 may be performed by a NE as described with reference to Figure 9.

[0186] It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0187] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMSWhat is claimed is:1 . A user equipment (UE), comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: generate a request for at least one transmission of at least one synchronization signal (SS)Zphysical broadcast channel (PBCH) block based at least in part on a condition; and transmit, to a first serving cell, a random access preamble, wherein the random access preamble indicates the request for the at least one transmission of the at least one SS / PBCH block associated with a second serving cell.

2. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive, from the second serving cell, the at least one SS / PBCH block based at least in part on the request, wherein the at least one SS / PBCH block comprises system information associated with the second serving cell.

3. The UE of claim 1, wherein the at least one processor is configured to cause the UE to: transmit assistance information associated with the request, wherein the assistance information indicates one or more of: an identifier of the request for the at least one SS / PBCH block; an identifier of the second serving cell; a quantity of SS / PBCH block transmissions; a pattern for a set of SS / PBCH block transmissions; a start time for monitoring for the at least one SS / PBCH block; a duration for monitoring for the at least one SS / PBCH block; or whether the requested at least SS / PBCH block corresponds to a partial SS / PBCH block or a full SS / PBCH block.

4. The UE of claim 3, wherein the random access preamble is transmitted during a random access procedure, and wherein the random access procedure comprises a four-step random access procedure, and wherein the random access preamble is associated with a first random access message of the four-step random access procedure.

5. The UE of claim 4, wherein the at least one processor is configured to cause the UE to: transmit a third random access message of the four-step random access procedure, wherein the third random access message includes the assistance information.

6. The UE of claim 3, wherein the random access preamble is transmitted during a random access procedure, and wherein the random access procedure comprises a two-step random access procedure, wherein the random access preamble is associated with a first random access message of the two-step random access procedure, and wherein the first random access message comprises the random access preamble and a random access payload.

7. The UE of claim 6, wherein the at least one processor is configured to cause the UE to: transmit the random access payload of the first random access message of the two-step random access procedure, wherein the random access payload includes the assistance information.

8. The UE of claim 7, wherein the at least one processor is configured to cause the UE to: determine an offset in a time domain between the random access preamble and the random access payload, wherein to transmit the random access payload including the assistance information is based at least in part on the offset.

9. The UE of claim 1, wherein the first serving cell is a primary cell (PCell), and wherein the second serving cell is a secondary cell (SCell).

10. The UE of claim 1, wherein the at least one processor is configured to cause the UE to: transmit the random access preamble that indicates the request in response to a timer expiring, and wherein a value of the timer is based at least in part on receiving a previous master information block (MIB) associated with the second serving cell.

11. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive a configuration to operate on the first serving cell or the second serving cell, and wherein the configuration is associated with the request.

12. The UE of claim 1, wherein the at least one processor is configured to cause the UE to receive a configuration for the UE to transmit the request for at least one transmission of the at least one SS / PBCH block.

13. The UE of claim 1, wherein the first serving cell is different from the second serving cell.

14. A processor for wireless communication, comprising: at least one controller coupled with at least one memory and configured to cause the processor to: generate a request for at least one transmission of at least one synchronization signal (SS)Zphysical broadcast channel (PBCH) block based at least in part on a condition; and transmit, to a first serving cell, a random access preamble, wherein the random access preamble indicates the request for the at least one transmission of the at least one SS / PBCH block associated with a second serving cell.

15. A method of a user equipment (UE), the method comprising :generating a request for at least one transmission of at least one synchronization signal (SS)Zphysical broadcast channel (PBCH) block based at least in part on a condition; and transmitting, to a first serving cell, a random access preamble, wherein the random access preamble indicates the request for the at least one transmission of the at least one SS / PBCH block associated with a second serving cell.

16. A base station, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the base station to: receive, at a first serving cell, a random access preamble, wherein the random access preamble indicates a request for at least one transmission of at least one synchronization signal (SS)Zphysical broadcast channel (PBCH) block associated with a second serving cell.

17. The base station of claim 16, wherein the at least one processor is configured to cause the base station to: receive assistance information associated with the request, wherein the assistance information indicates one or more of: an identifier of the request for the at least one SSZPBCH block; an identifier of the second serving cell; a quantity of SSZPBCH block transmissions; a pattern for a set of SSZPBCH block transmissions; a start time for monitoring for the at least one SSZPBCH block; a duration for monitoring for the at least one SSZPBCH block; or whether the requested at least SSZPBCH block corresponds to a partial SSZPBCH block or a full SSZPBCH block.

18. The base station of claim 17, wherein the random access preamble is received during a random access procedure, and wherein the random access procedure comprises a four-step random access procedure, and wherein the random accesspreamble is associated with a first random access message of the four-step random access procedure.

19. The base station of claim 18, wherein the at least one processor is configured to cause the base station to: receive a third random access message of the four-step random access procedure, wherein the third random access message includes the assistance information.

20. The base station of claim 17, wherein the random access preamble is received during a random access procedure, and wherein the random access procedure comprises a two-step random access procedure, wherein the random access preamble is associated with a first random access message of the two-step random access procedure, and wherein the first random access message comprises the random access preamble and a random access payload.

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