WO2023130296A1

WO2023130296A1 - Coverage recovery for punctured physical broadcast channel

Info

Publication number: WO2023130296A1
Application number: PCT/CN2022/070438
Authority: WO
Inventors: Jing Dai; Chao Wei; Changlong Xu; Le LIU
Original assignee: Qualcomm Incorporated
Priority date: 2022-01-06
Filing date: 2022-01-06
Publication date: 2023-07-13

Abstract

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for coverage recovery for punctured physical broadcast channels (PBCH). For system bandwidths less than 5 MHz, a base station punctures a PBCH by not transmitting a first set of resource blocks (RBs) of the PBCH in a first SSB. The base station transmits a second SSB that includes the PBCH having a second set of punctured RBs. A user equipment (UE) receives the first SSB on a bandwidth less than 5 MHz, the first SSB including a PBCH having a first set of resource blocks that have been punctured. The UE receives the second SSB on the bandwidth, the second SSB including the PBCH having a second set of RBs that have been punctured. The UE may combine the PBCH from the first SSB and the PBCH from the second SSB to decode the PBCH.

Description

COVERAGE RECOVERY FOR PUNCTURED PHYSICAL BROADCAST CHANNEL

TECHNICAL FIELD

The present disclosure relates to wireless communications where a physical broadcast channel may be punctured, for example, due to a narrow system bandwidth.

DESCRIPTION OF THE RELATED TECHNOLOGY

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) . 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (such as with Internet of Things (IoT) ) , and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra-reliable low latency communications (URLLC) . Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard.

SUMMARY

The systems, methods and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

One innovative aspect of the subject matter described in this disclosure can be implemented in a method of wireless communication at an apparatus of a user equipment (UE) . The method may include receiving a first synchronization signal block (SSB) on a bandwidth less than 5 MHz, the first SSB including a physical broadcast channel (PBCH) having a first set of resource blocks that have been punctured. The method may include receiving a second SSB on the bandwidth, the second SSB including the PBCH having a second set of resource blocks that have been punctured.

The present disclosure also provides an apparatus (e.g., a UE) including a memory storing computer-executable instructions and at least one processor configured to execute the computer-executable instructions to perform the above method, an apparatus including means for performing the above method, and a non-transitory computer-readable medium storing computer-executable instructions for performing the above method.

One innovative aspect of the subject matter described in this disclosure can be implemented in a method of wireless communication at an apparatus of a base station (BS) . The method may include transmitting a first SSB including a PBCH on a bandwidth less than 5 MHz, wherein transmitting the first SSB includes puncturing a first set of resource blocks of the PBCH. The method may include transmitting a second SSB including the PBCH on the bandwidth, wherein transmitting the second SSB includes puncturing a second set of resource blocks of the PBCH.

The present disclosure also provides an apparatus (e.g., a BS) including a memory storing computer-executable instructions and at least one processor configured to execute the computer-executable instructions to perform the above method, an apparatus including means for performing the above method, and a non-transitory computer-readable medium storing computer-executable instructions for performing the above method.

Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.

FIG. 2A is a diagram illustrating an example of a first frame.

FIG. 2B is a diagram illustrating an example of DL channels within a subframe.

FIG. 2C is a diagram illustrating an example of a second frame.

FIG. 2D is a diagram illustrating an example of a subframe.

FIG. 3 is a diagram illustrating an example of a base station (BS) and user equipment (UE) in an access network.

FIG. 4 is a diagram illustrating an example of PBCH encoding, rate matching, and channel mapping.

FIG. 5 is a diagram illustrating an example of SSBs with different puncture patterns of RBs.

FIG. 6 is a diagram of example transmission patterns for SSBs with different puncturing patterns.

FIG. 7 is a diagram of SSBs having different circulant bit offsets for bit-to-RE mapping.

FIG. 8 is a conceptual data flow diagram illustrating the data flow between different means/components in an example base station.

FIG. 9 is a conceptual data flow diagram illustrating the data flow between different means/components in an example UE.

FIG. 10 is a flowchart of an example method for a UE to receive two or more SSBs including a PBCH that has been punctured.

FIG. 11 is a flowchart of an example method for a base station to transmit multiple SSBs including a PBCH that is punctured.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

The following description is directed to certain implementations for the purposes of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. Some of the examples in this disclosure are based on wireless and wired local area network (LAN) communication according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless standards, the IEEE 802.3 Ethernet standards, and the IEEE 1901 Powerline communication (PLC) standards. However, the described implementations may be implemented in any device, system or network that is capable of transmitting and receiving RF signals according to any of the wireless communication standards, including any of the IEEE 802.11 standards, the

standard, code division multiple access (CDMA) , frequency division multiple access (FDMA) , time division multiple access (TDMA) , Global System for Mobile communications (GSM) , GSM/General Packet Radio Service (GPRS) , Enhanced Data GSM Environment (EDGE) , Terrestrial Trunked Radio (TETRA) , Wideband-CDMA (W-CDMA) , Evolution Data Optimized (EV-DO) , 1xEV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA) , High Speed Downlink Packet Access (HSDPA) , High Speed Uplink Packet Access (HSUPA) , Evolved High Speed Packet Access (HSPA+) , Long Term Evolution (LTE) , AMPS, or other known signals that are used to communicate within a wireless, cellular or internet of things (IOT) network, such as a system utilizing 3G, 4G or 5G, or further implementations thereof, technology.

A 5G NR system may conventionally use a bandwidth greater than 5 GHz. For example, a physical broadcast channel (PBCH) may be transmitted over 20 resource blocks (RBs) , which may have a bandwidth of 3.6 MHz at a sub-carrier spacing of 15 kHz.

There may be some use cases where bandwidths smaller than 5 MHz are desired. For example, some existing frequency bands may be licensed in sizes less than 5 MHz. It may be desirable to repurpose such frequency bands, for instance, for smart grid private networks or railway mobile communication systems. If a current design of the PBCH is used for such networks, it may not be possible to transmit the entire bandwidth of the PBCH. One proposal for operating 5G NR on bandwidths less than 5 GHz is to simply puncture some of the resource elements (REs) or RBs of the PBCH. That is, some of the REs (e.g., those at an upper or lower boundary of the system bandwidth) may not be transmitted. Generally, the PBCH is encoded at a relatively low coding rate, and the PBCH may be recovered from the remaining symbols. However, puncturing of the PBCH may result in more severe performance degradation than expected based on the number of punctured REs. For example, puncturing four RBs (e.g., for a 3MHz system with 16 RBs) has been observed to result in a 2.2 dB loss of signal to noise ratio (SNR) on some devices compared to an expected 1.2 dB loss based on 48 remaining non-punctured PBCH RBs over 3 symbols.

In an aspect, the present disclosure provides for techniques to improve recovery of a PBCH that has been punctured. Generally, the PBCH may be transmitted in at least two synchronization signal blocks (SSBs) that have different properties that result in different bits of the PBCH being punctured. A UE may receive different SSBs and combine the bits for the PBCH to improve decoding recovery of the PBCH. In one example, the SSBs may have different puncturing patterns such that different RBs are punctured. In another example, the encoded bits of the PBCH may be mapped to the REs using different circulant bit offsets such that the punctured REs are based on different bits. In either case, the UE may receive a full set of the encoded bits of the PBCH over two or more SSBs. Accordingly, the UE may be more likely to be able to recover the PBCH from the received SSBs than from a single punctured SSB.

Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. System bandwidths less than 5 MHz may be utilized to provide 5G NR service without severe reductions in SNR of PBCH. The higher SNR of the recovered PBCH allows greater coverage area of the PBCH.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. The processor may include an interface or be coupled to an interface that can obtain or output signals. The processor may obtain signals via the interface and output signals via the interface. In some implementations, the interface may be a printed circuit board (PCB) transmission line. In some other implementations, the interface may include a wireless transmitter, a wireless transceiver, or a combination thereof. For example, the interface may include a radio frequency (RF) transceiver which can be implemented to receive or transmit signals, or both. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example implementations, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media, which may be referred to as non-transitory computer-readable media. Non-transitory computer-readable media may exclude transitory signals. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and another core network 190 (such as a 5G Core (5GC) ) . The base stations 102 may include macrocells (high power cellular base station) or small cells (low power cellular base station) . The macrocells include base stations. The small cells include femtocells, picocells, and microcells. The small cells include femtocells, picocells, and microcells. The base stations 102 can be configured in a Disaggregated RAN (D-RAN) or Open RAN (O-RAN) architecture, where functionality is split between multiple units such as a central unit (CU) , one or more distributed units (DUs) , or a radio unit (RU) . Such architectures may be configured to utilize a protocol stack that is logically split between one or more units (such as one or more CUs and one or more DUs) . In some aspects, the CUs may be implemented within an edge RAN node, and in some aspects, one or more DUs may be co-located with a CU, or may be geographically distributed throughout one or multiple RAN nodes. The DUs may be implemented to communicate with one or more RUs.

In some implementations, one or more of the UEs 104 may include a PBCH recovery component 140 that recovers a PBCH that has been punctured from two or more SSBs. The PBCH hopping component 140 may include a first SSB component 142 configured to receive a first SSB on a bandwidth less than 5 MHz, the first SSB including a PBCH having a first set of resource blocks that have been punctured. The PBCH recovery component 140 may include a second SSB component 144 configured to receive a second SSB on the bandwidth, the second SSB including the PBCH having a second set of resource blocks that have been punctured. In some implementations, the PBCH recovery component 140 may optionally include a combining component 146 configured to combine the PBCH from the first SSB and the PBCH from the second SSB to decode the PBCH.

In some implementations, one or more of the base stations 102 may include a PBCH puncturing component 120 configured to transmit SSBs with different properties of a punctured PBCH. The PBCH puncturing component 120 may include a first SSB transmit (TX) component 122 configured to transmit a first SSB including a PBCH on a bandwidth less than 5 MHz. Transmitting the first SSB includes puncturing a first set of resource blocks of the PBCH. The PBCH puncturing component 120 may include a second SSB TX component 124 configured to transmit a second SSB including the PBCH on the bandwidth. Transmitting the second SSB includes puncturing a second set of resource blocks of the PBCH.

The base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through first backhaul links 132 (such as S1 interface) , which may be wired or wireless. The base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN) ) may interface with core network 190 through second backhaul links 184, which may be wired or wireless. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (such as handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (such as through the EPC 160 or core network 190) with each other over third backhaul links 134 (such as X2 interface) . The third backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102'may have a coverage area 110'that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network also may include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 112 between the base stations 102 and the UEs 104 may include UL (also referred to as reverse link) transmissions from a UE 104 to a base station 102 or DL (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 112 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y MHz (such as 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (such as more or fewer carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102'may operate in a licensed or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102'may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to or increase capacity of the access network.

A base station 102, whether a small cell 102'or a large cell (such as macro base station) , may include an eNB, gNodeB (gNB) , or other type of base station. Some base stations, such as gNB 180 may operate in one or more frequency bands within the electromagnetic spectrum.

The electromagnetic spectrum is often subdivided, based on frequency/wavelength, into various classes, bands, channels, etc. In 5G NR two initial operating bands have been identified as frequency range designations FR1 (410 MHz –7.125 GHz) and FR2 (24.25 GHz –52.6 GHz) . The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “Sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” (mmW) band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz –300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.

With the above aspects in mind, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like if used herein may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like if used herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, or may be within the EHF band. Communications using the mmW radio frequency band have extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the path loss and short range.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The core network 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, or other IP services.

The base station may include or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (such as a MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (such as a parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . The UE 104 also may be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies including future 6G technologies.

FIG. 2A is a diagram 200 illustrating an example of a first frame. FIG. 2B is a diagram 230 illustrating an example of DL channels within a subframe. FIG. 2C is a diagram 250 illustrating an example of a second frame. FIG. 2D is a diagram 280 illustrating an example of a subframe. The 5G NR frame structure may be FDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be TDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL. A subset of the total cell bandwidth of a cell is referred to as a Bandwidth Part (BWP) and bandwidth adaptation is achieved by configuring the UE with BWP (s) and telling the UE which of the configured BWPs is currently the active one.

In the examples provided by Figs. 2A, 2C, the 5G NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL) , where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 being configured with slot format 34 (with mostly UL) . While

subframes

3, 4 are shown with slot formats 34, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) . Note that the description infra applies also to a 5G NR frame structure that is TDD.

Other wireless communication technologies may have a different frame structure or different channels. A frame (10 milliseconds (ms) ) may be divided into 10 equally sized subframes (1 ms) . Each subframe may include one or more time slots. Subframes also may include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission) . The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies μ 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2 ^μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2 ^μ*15kHz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing. Figs. 2A–2D provide an example of slot configuration 0 with 14 symbols per slot and numerology μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 microseconds (μs) .

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (indicated as R _x for one particular configuration, where 100x is the port number, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS also may include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .

FIG. 2B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DM-RS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block (SSB) . The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in Figure 2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH) . The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. The UE may transmit sounding reference signals (SRS) . The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

Figure 2D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , or UCI.

Figure 3 is a diagram of an example of a base station 310 and a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (such as MIB, SIBs) , RRC connection control (such as RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (such as binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may be split into parallel streams. Each stream may be mapped to an OFDM subcarrier, multiplexed with a reference signal (such as a pilot) in the time or frequency domain, and combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal or channel condition feedback transmitted by the UE 350. Each spatial stream may be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller/processor 359 is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (such as MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160. The controller/processor 375 is also responsible for error detection using an ACK or NACK protocol to support HARQ operations.

At least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with the PBCH recovery component 140 of FIG. 1. For example, the memory 360 may include executable instructions defining the PBCH recovery component 140. The TX processor 368, the RX processor 356, and/or the controller/processor 359 may be configured to execute the PBCH recovery component 140.

At least one of the TX processor 316, the RX processor 370, and the controller/processor 375 may be configured to perform aspects in connection with the PBCH puncturing component 120 of FIG. 1. For example, the memory 376 may include executable instructions defining the PBCH puncturing component 120. The TX processor 316, the RX processor 370, and/or the controller/processor 375 may be configured to execute the PBCH puncturing component 120.

FIG. 4 is a diagram 400 illustrating an example of PBCH encoding, rate matching, and channel mapping. A PBCH 420 may be transmitted on an SSB 410 that also includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) . The SSB 410 may span 20 RBs or 240 subcarriers. The PBCH 420 may conventionally use a total of 48 RBs over its last 3 symbols (where 20, 8 and 20 RBs for PBCH are allocated in the last 3 symbols respectively) . In an aspect, a system bandwidth 440 may be less than 5 MHz. For example, if the SSB 410 is to be transmitted on a system bandwidth 440 of 3 MHz, for example, there may be only 16 RBs for a subcarrier spacing of 15 kHz. Puncturing may be used to reduce the bandwidth of the SSB 410 by not transmitting the 4 RBs (i.e., punctured resource blocks 430) assigned to punctured resources at the top of the system bandwidth 440.

One explanation for the severe performance degradation of a punctured PBCH is due to the puncturing of the Polar code used for PBCH. A PBCH with a total of 48 RBs may be based on a total of 864 encoded bits (e.g., encoded bit length E = 864) . A mother code of 2^9 = 512 may be chosen for rate matching. The encoded bits may be read from a circular buffer 450 storing the mother code. That is, bits 512 -863 may be redundant with bits 0 –351. However, with the roof 4 RBs punctured, there can be a total of 144 bits that are not transmitted for the 512-bit mother code. For example, the first symbol of the PBCH 420 may include bits 288 –359 within the punctured resource blocks 430, the second symbol of the PBCH 420 may include bits 432-503 within the punctured resource blocks 430, and the third symbol of the PBCH 420 may include bits 792 –863 within the punctured resource blocks 430. Accordingly, when the punctured resource blocks 430 are not transmitted, bits 288 –359 (72 bits) and 432 –503 (72 bits) are not transmitted. Therefore, decoding of the PBCH may be based on only 376 of the encoded bits.

FIG. 5 is a diagram 500 illustrating an example of SSBs with different puncture patterns of RBs. In the illustrated example, a first SSB 510 may be the same as the SSB 410, where the punctured resource blocks 530 include 4 RBs above the roof of the system bandwidth 440. Accordingly, the SSB 510 may result in the same transmitted bits as discussed above regarding FIG. 4.

A second SSB 520 may have a different puncturing pattern. For example, 4 RBs below the floor of the system bandwidth 440 may be included in punctured resource blocks 530. For instance, the base station may shift the center frequency of the SSB 520. The center frequency of the SSB may be indicated by the location of the PSS and SSS. In the illustrated example, the center frequency is shifted downward such that lower indexed RBs are below a floor of the system bandwidth 440. Accordingly, because different RBs in the second SSB 520 are punctured than in the first SSB 510, a different set of bits of the PBCH 420 may be carried in the second SSB 520. The RBs that were included in the punctured resource blocks 430 for the first SSB may be transmitted in the second SSB 520. Accordingly, between the two SSBs, the UE 104 may receive all bits of the PBCH 420.

FIG. 6 is a diagram 600 of example transmission patterns for SSBs with different puncturing patterns. For TX beam sweeping, an SSB burst set 616 is confined within 5 ms (a half frame) . For 15 kHz SCS, an SSB burst set has 4 SSBs, located in symbols {2, 3, 4, and 5} and {8, 9, 10, and 11} of both the first two slots (slot 0 and 1) respectively, within a half frame (5 slots) . During a cell search, the UE assumes the (default) periodicity of the SSB burst set 616 as 20 milliseconds (ms) (2 frames) , but the actual periodicity may be decided by network implementation (e.g., configurable as 5, 10, 20, 40, 80, or 160 ms) . Where SSBs with different puncturing patterns are transmitted, it may be desirable to maintain the SSB burst set confined within 5 ms.

In a first configuration 610, a first SSB burst 612 having a first puncturing pattern may be transmitted in the first two slots (slot indices 0 and 1) , and a second SSB burst 614 having a second puncturing pattern may be transmitted in the third and fourth slots (slot indices 2 and 3) . The first two slots may be a first portion of the SSB burst set 616 and the third and fourth slots may be a second portion of the SSB burst set 616. In some implementations, the first puncture pattern is in an SSB burst 612 that is adjacent to an SSB burst 614 with the second puncture pattern. Accordingly, SSBs having both puncturing patterns may be transmitted in the same SSB burst set 616 within a 5 ms half frame.

In a second configuration 620, a first SSB burst set 626 includes an SSB burst 622 with a first puncture pattern and a second SSB burst set 628 includes an SSB burst 624 with a second puncture pattern. The UE may receive a first SSB 510 in the SSB burst 622 in the first SSB burst set 626 and receive the second SSB 520 in the SSB burst 624 in the second SSB burst set 628. In some implementations, a time offset (e.g., SSB offset 630) between a start of the first SSB burst set 626 and the second SSB burst set 628 is equal to half of a periodicity of the first SSB burst set and the second SSB burst set. For example, the first SSB burst set and the second SSB burst set may each have a periodicity of 10 ms and be offset by 5 ms. As another example, the first SSB burst set and the second SSB burst set may each have a periodicity of 20 ms and be offset by 10 ms.

During a cell search, the UE may assume a default periodicity of the SSB burst set. For example, the UE may assume that the default periodicity is half of the assumed periodicity of a conventional NR system. If the UE assumes that the periodicity is 10 ms, the UE may receive both SSB burst sets within the conventional 20 ms periodicity. As another example, the UE may assume the same default periodicity of 20 ms for each SSB burst set. The UE may receive both SSB burst sets within a 40 ms periodicity.

FIG. 7 is a diagram 700 of examples of SSBs having different circulant bit offsets for bit-to-RE mapping. In the illustrated example, a first SSB 710 may be the same as the SSB 410, where the punctured resource blocks 730 include 4 RBs above the roof of the system bandwidth 440. The circulant bit offset for bit-to-RE mapping may be set to 0 for the first SSB 710. Accordingly, bit 0 may be mapped to RE index 0, and sequential bits may be sequentially mapped to the assigned REs in a frequency first order. Accordingly, the SSB 710 may result in the same transmitted bits as discussed above regarding FIG. 4.

A second SSB 720 may have a different circulant bit offset for bit-to-RE mapping. For example, in the illustrated example, the circulant bit offset may be -80 or 432. In some implementations, the circulant bit offset may be added to an index of the encoded bit when reading from the circular buffer 450. Accordingly, instead of mapping bit 0 to RE index 0, the base station 102 may map bit 432 to RE index 0 and sequentially map the bits to REs in a frequency first order. Accordingly, for the second SSB 720, the punctured resource blocks 730, which may be the same RBs as the first SSB 710, may include bits 208 –279 and 352 –423. Accordingly, there may be no overlap in the punctured bits between the first SSB 710 and the second SSB 720. The UE may receive each bit on at least one of the first SSB 710 or the second SSB 720.

The first SSB 710 may be transmitted in a first SSB burst and the second SSB may be transmitted in a second SSB burst. The first SSB burst and the second SSB burst may be in different half-frames. During a cell search, the UE may assume a default periodicity of 20 ms, which is the same as in conventional 5G NR implementations with a single SSB burst set. The frequency location of the PSS and SSS does not change between the first SSB 710 and the second SSB 720. In some implementations, the presence of the two different SSBs may be indicated via a PBCH DMRS sequence. The PBCH DMRS sequence may conventionally be based in part on a half-frame indication factor η _hf, which may be redundant with a half-frame indication bit in the PBCH payload. The half-frame indication factor η _hf may be re-interpreted to indicate the circulant bit offset value for PBCH bit-to-RE mapping. That is, the PBCH DMRS sequence may indicate whether an associated SSB uses a circulant bit offset of 0 or another value (e.g., -80) . For example, the initialization parameter for PBCH DMRS may be defined as:

where when

where n _hf indicates the circulant bit offset, and iSSB is the two least significant bits of the candidate SS/PBCH block index. For example, n _hf may have a value of 0 if the circulant bit offset is 0 or a value of 1 if a different circulant bit offset is used.

In some implementations, further adaptations of 5G NR may be applicable to bandwidths less than 5 MHz. For example, with a system bandwidth 440 of 3 MHz or 16 PRBs, a PDSCH with 10 data symbols and QPSK modulation may accommodate a maximum of 3840 encoded bits. A first system information block (SIB1) may be transmitted on PDSCH and have a size of 1700 bits, which corresponds to a coding rate of 0.44. Conventionally, SIB1 may have a repetition period of 160 ms, which may be a long latency for some use cases such as railway systems. In an aspect, the SIB1 PDSCH may be repeated in consecutive slots. The repeated slots may be defined in a standard, indicated by the master information block (MIB) or the PBCH, or by a SIB1 PDCCH that schedules the SIB1. For instance, one or more bits or fields of existing messages may be reinterpreted for bandwidths less than 5 MHz. For instance, the MIB may include a common SCS field, an SSB carrier offset field, a CORESET#0 indicator in PDCCH-ConfigSIB1, or a spare bit. The PBCH may include two reserved bits that may be repurposed. The SIB1 PDCCH field may include a time domain resource allocation (TDRA) field, a VRB-to-PRB mapping field, or reserved bits. In some implementations the SIB1 PDSCH may be repeated with different redundancy versions to improve decoding.

FIG. 8 is a conceptual data flow diagram 800 illustrating the data flow between different means/components in an example base station 802, which may be an example of the base station 102 including the PBCH puncturing component 120. The PBCH puncturing component 120 may be implemented by the memory 376 and the TX processor 316, the RX processor 370, and/or the controller/processor 375 of FIG. 3. For example, the memory 376 may store executable instructions defining the PBCH puncturing component 120 and the TX processor 316, the RX processor 370, and/or the controller/processor 375 may execute the instructions.

The base station 102 may include a receiver component 850, which may include, for example, a radio frequency (RF) receiver for receiving the signals described herein. The base station 102 may include a transmitter component 852, which may include, for example, an RF transmitter for transmitting the signals described herein. In an aspect, the receiver component 850 and the transmitter component 852 may co-located in a transceiver such as illustrated by the TX/RX 318 in FIG. 3.

As discussed with respect to FIG. 1, the PBCH puncturing component 120 may include the first SSB TX component 122 and the second SSB TX component 124. In some implementations, the PBCH puncturing component 120 includes an encoder 860. The encoder 860 may receive a PBCH 420 from higher layers. The PBCH 420 may include bits representing information fields of the PBCH 420. The encoder 860 may perform Polar coding of the PBCH 420 to produce encoded bits 864. The encoder 860 may provide the encoded bits 864 to both the first SSB TX component 122 and the second SSB TX component 124.

The first SSB TX component 122 may generate a

first SSB

510, 710 for transmission. The first SSB TX component 122 may be configured with a system bandwidth 440 that is less than 5 MHz. The first SSB TX component 122 may be configured with punctured RBs 812, which may correspond to the example punctured resource blocks 430, 530, or 730. The first SSB TX component 122 may include a rate matching component 830 configured to select bits for transmission and a mapper 832 configured to map the selected bits to resource elements. For example, the rate matching component 830 may select bits from the encoded bits 864 starting at the first circulant bit offset 834. In some implementations, the first SSB TX component 122 may be configured with a first puncture pattern 814. The first SSB TX component 122 may select the first punctured RBs 812 based on the first puncture pattern 814, then transmit the remaining bits on the system bandwidth 440. For example, the first SSB TX component 122 may periodically transmit the

first SSB

510, 710 according to a periodicity 840 via the transmitter component 852. Further, it should be understood that transmitting the

first SSB

510, 720 may include transmitting the

first SSB

510, 710 on different beams over an SSB burst.

The second SSB TX component 124 may operate in the same manner as the first SSB TX component 122, but may be configured with different parameters. For example, the second punctured RBs 822 and/or the second puncture pattern 824 may be different than the first punctured RBs 812 and/or the first puncture pattern 814, respectively. Accordingly, the second SSB TX component 124 may puncture a different set of RBs for the second SSB 520 compared to the first SSB 510, as illustrated in FIG. 5. As another example, the second circulant bit offset 836 may be different than the first circulant bit offset 834. Accordingly, the bits mapped to the punctured RBs may be different for the second SSB 720 compared to the first SSB 710, as illustrated in FIG. 7. The second SSB TX component 124 may periodically transmit the

second SSB

520, 720 according to a periodicity 840 via the transmitter component 852. The

second SSB

520, 720 may be offset from the

first SSB

510, 710 by an SSB offset 842.

The receiver component 850 may receive UL signals from the UE 104 including UL communications. In some implementations, the receiver component 850 may optionally receive a random access message from the UE 104 seeking to connect to the base station 802.

FIG. 9 is a conceptual data flow diagram 900 illustrating the data flow between different means/components in an example UE 904, which may be an example of the UE 104 and include the PBCH recovery component 140. The PBCH recovery component 140 may be implemented by the memory 360 and the TX processor 368, the RX processor 356, and/or the controller/processor 359. For example, the memory 360 may store executable instructions defining the PBCH recovery component 140 and the TX processor 368, the RX processor 356, and/or the controller/processor 359 may execute the instructions.

The UE 104 may include a receiver component 970, which may include, for example, a RF receiver for receiving the signals described herein. The UE 104 may include a transmitter component 972, which may include, for example, an RF transmitter for transmitting the signals described herein. In an aspect, the receiver component 970 and the transmitter component 972 may co-located in a transceiver such as the TX/RX 352 in FIG. 3.

As discussed with respect to FIG. 1, the PBCH recovery component 140 may include the first SSB component 142 and the second SSB component 144. The PBCH recovery component 140 may optionally include the combining component 146.

The receiver component 970 may receive DL signals described herein such as the

first SSB

510, 710 and the

second SSB

520, 720. The receiver component 970 may provide the

first SSB

510, 710 to the first SSB component 142 and provide the

second SSB

520, 720 to the second SSB component 144. In some implementations, the receiver component 970 may include a DMRS component 974 that is configured to determine a circulant bit offset value for bit-to-RE mapping based on a DMRS sequence. For instance, the DMRS component 974 may determine n _hf from the timing of the SSB and the DMRS sequence. The DMRS component 974 may determine whether the received SSB is a first SSB or a second SSB based on the indicated circulant bit offset. In some implementations, the receiver component 970 may determine a PSS/SSS center frequency 976. The receiver component 970 may determine whether the received SSB is a first SSB or a second SSB based on the PSS/SSS center frequency 976.

The first SSB component 142 may be configured to receive a

first SSB

510, 710 on a bandwidth less than 5 MHz. For example, the first SSB component 142 may receive the

first SSB

510, 710 via the receiver component 970 according to a default periodicity 940. The first SSB component 142 may include a demapper 932 configured to determine received encoded bits from the received SSB. For example, the demapper 932 may be configured with the first circulant bit offset 834. The demapper 932 may determine received symbols for each RE. A demodulator may determine a coded bit sequence. The rate matching component 930 may assign received signals to a circular buffer 450 for the PBCH 420 based on the first circulant bit offset. Accordingly, signals for the same bit in different REs may be combined.

The second SSB component 144 may be configured to receive a second SSB on the system bandwidth 440. The second SSB may include the PBCH 420 having a second set of RBs 822 that have been punctured. For example, the second set of RBs 822 may be punctured according to the second puncture pattern 824. For instance, the demapper 932 may identify the second set of RBs 822 and/or the second puncture pattern 824 based on the PSS/SSS center frequency 976 or a signal from the receiver component 970. The demapper 932 may map the received signal to REs based on the second puncture pattern 824. In another example, the second punctured RBs 822 may be the same as the first punctured RBs 812, but the second circulant bit offset 836 may be different than the first circulant bit offset 834. The rate matching component 930 may assign the demodulated bit sequence to the circular buffer 450 based on the second circulant bit offset 836.

In some implementations, the PBCH recovery component 140 may include the combining component 146. The combining component 146 may be configured to combine the PBCH 420 from the first SSB and the PBCH 420 from the second SSB to decode the PBCH. For example, the combining component 146 may include the circular buffer 450. The combining component 146 may store the demodulated encoded bits from the first SSB component 142 in the circular buffer 450 and combine the demodulated encoded bits from the second SSB component 144 with the stored bits. The combining component 146 may perform polar decoding on the stored bits of the circular buffer 450 to decode the PBCH 420.

FIG. 10 is a flowchart of an example method 1000 for a UE to receive two or more SSBs including a PBCH that has been punctured. The method 1000 may be performed by a UE (such as the UE 104, which may include the memory 360 and which may be the entire UE 104 or a component of the UE 104 such as the PBCH recovery component 140, TX processor 368, the RX processor 356, or the controller/processor 359) . The method 1000 may be performed by the PBCH recovery component 140 in communication with the PBCH puncturing component 120 of the base station 102. Optional blocks are shown with dashed lines.

At block 1010, the method 1000 may include receiving a first SSB on a bandwidth less than 5 MHz. The

first SSB

510, 710 includes a PBCH having a first set of resource blocks that have been punctured. In some implementations, for example, the UE 104, the RX processor 356 or the controller/processor 359 may execute the PBCH recovery component 140 or the first SSB component 142 to receive the

first SSB

510, 710 on a bandwidth (e.g., system bandwidth 440) less than 5 MHz. The

first SSB

510, 710 includes a PBCH 420 having a first set of punctured resource blocks 430, 730 that have been punctured. Accordingly, the UE 104, the RX processor 356, or the controller/processor 359 executing the PBCH recovery component 140 or the first SSB component 142 may provide means for receiving a second SSB on the bandwidth.

At block 1020, the method 1000 may include receiving a second SSB on the bandwidth. In some implementations, for example, the UE 104, the RX processor 356 or the controller/processor 359 may execute the PBCH recovery component 140 or the second SSB component 144 to receive a

second SSB

520, 720 on the bandwidth. The

second SSB

520, 720 including the PBCH 420 having a second set of resource blocks 530, 730 that have been punctured. Accordingly, the UE 104, the RX processor 356, or the controller/processor 359 executing the PBCH recovery component 140 or the second SSB component 144 may provide means for receiving a second SSB on the bandwidth.

In some implementations, the first SSB 510 follows a different puncture pattern than the second SSB 520 such that the first set of punctured resource blocks 430 and the second set of punctured resource blocks 530 are different. In such implementations, the first circulant bit offset 834 and the second circulant bit offset 836 may be the same. In some implementations, the first SSB 510 is received in a first portion (e.g., SSB burst 612) of an SSB burst set 616 and the second SSB 520 is received in a second portion (e.g., SSB burst 614) of the SSB burst set 616. In some implementations, the first puncture pattern is in an SSB burst 612 adjacent to an SSB burst 614 with the second puncture pattern. In some implementations, the first SSB 510 is received in a first SSB burst set 626 and the second SSB 520 is received in a second SSB burst set 628. A time offset 630 between a start of the first SSB burst set 626 and the second SSB burst set 628 may be equal to half of a periodicity of the first SSB burst set and the second SSB burst set. For example, a default periodicity for a cell search may be 20 ms for both of the first SSB burst set and the second SSB burst set. As another example, a default periodicity for a cell search may be 40 ms for both of the first SSB burst set and the second SSB burst set.

In some implementations, the first SSB 710 has a different circulant bit offset for bit-to-RE mapping than the second SSB 720 such that the first set of resource blocks 730 includes different bits than the second set of resource blocks 730. The first set of resource blocks 730 may be the same as the second set of resource blocks 730. In some implementations, the first SSB 710 is received in a first SSB burst set 626 with a first circulant bit offset and the second SSB 720 is received in a second SSB burst set 628 with a second circulant bit offset. A default periodicity for a cell search of the first SSB burst set and the second SSB burst set may be 20 ms. In some implementations, a DMRS sequence indicates the circulant bit offset value for bit-to-RE mapping.

At block 1030, the method 1000 may optionally include combining the PBCH from the first SSB and the PBCH from the second SSB to decode the PBCH. In some implementations, for example, the UE 104, the RX processor 356, the TX processor 368, or the controller/processor 359 may execute the PBCH recovery component 140 or the combining component 146 to combine the PBCH 420 from the first SSB and the PBCH from the second SSB to decode the PBCH. The bits of the PBCH 420 from the

first SSB

510, 710 may be different from the bits of the PBCH 420 from the

second SSB

520, 720, so the combined PBCH may include all bits of the mother code. The likelihood of decoding the combined PBCH may be increased, thereby improving the coverage of the PBCH. Accordingly, the UE 104, the RX processor 356, the TX processor 368, or the controller/processor 359 executing the PBCH recovery component 140 or the combining component 146 may provide means for combining the PBCH from the first SSB and the PBCH from the second SSB to decode the PBCH.

At block 1040, the method 1000 may optionally include receiving at least two repetitions of a SIB1 PDSCH in at least two consecutive slots on the bandwidth. In some implementations, for example, the UE 104, the RX processor 356, or the controller/processor 359 may execute the PBCH recovery component 140 or the receiver component 970 to receive the at least two repetitions of the SIB1 PDSCH in at least two consecutive slots on the bandwidth. In some implementations, repetition of the SIB1 PDSCH is indicated by one or more fields of the PBCH or a SIB1 PDCCH. In some implementations, the at least two repetitions of the SIB1 PDSCH have different redundancy versions. For example, the different redundancy versions may improve decoding of the SIB1 PDSCH in cases where the SIB1 PDSCH is punctured or transmitted with a high coding rate. Accordingly, the UE 104, the RX processor 356, or the controller/processor 359 executing the PBCH recovery component 140 or the receiver component 970 may provide means for receiving at least two repetitions of a SIB1 PDSCH in at least two consecutive slots on the bandwidth.

FIG. 11 is a flowchart of an example method 1100 for a base station to transmit multiple SSBs including a PBCH that is punctured. The method 1100 may be performed by a base station (such as the base station 102, which may include the memory 376 and which may be the entire base station 102 or a component of the base station 102 such as the PBCH puncturing component 120, the TX processor 316, the RX processor 370, or the controller/processor 375) . The method 1000 may be performed by the PBCH puncturing component 120 in communication with the PBCH recovery component 140 of the UE 104.

At block 1110, the method 1100 may include transmitting a first SSB including a PBCH on a bandwidth less than 5 MHz. In some implementations, for example, the base station 102, the TX processor 316, or the controller/processor 375 may execute the PBCH puncturing component 120 or the first SSB TX component 122 to transmit the

first SSB

510, 710 including the PBCH on a bandwidth 440 less than 5 MHz. Transmitting the

first SSB

510, 710 includes, at sub-block 1112, puncturing a first set of punctured resource blocks 430.730 of the PBCH 420. Accordingly, the base station 102, the TX processor 316, or the controller/processor 375 executing the PBCH puncturing component 120 or the first SSB TX component 122 may provide means for transmitting a first SSB including a PBCH on a bandwidth less than 5 MHz.

At block 1120, the method 1000 may include transmitting a second SSB including the PBCH on the bandwidth. In some implementations, for example, base station 102, the TX processor 316, or the controller/processor 375 may execute the PBCH puncturing component 120 or the second SSB TX component 124 to transmit the

second SSB

520, 720 including the PBCH 420 on the bandwidth 440. Transmitting the second SSB includes, at sub-block 1122, puncturing a second set of resource blocks 530, 730 of the PBCH 420. Accordingly, the base station 102, the TX processor 316, or the controller/processor 375 executing the PBCH puncturing component 120 or the second SSB TX component 124 may provide means for transmitting a second SSB including the PBCH on the bandwidth.

In some implementations, the first SSB 510 follows a different puncture pattern than the second SSB 520 such that the first set of punctured resource blocks 430 and the second set of resource blocks 530 are different. In such implementations, the first circulant bit offset 834 and the second circulant bit offset 836 may be the same. In some implementations, the first SSB 510 is transmitted in a first portion (e.g., SSB burst 612) of an SSB burst set 616 and the second SSB 520 is transmitted in a second portion (e.g., SSB burst 614) of the SSB burst set 616. In some implementations, the first puncture pattern is in an SSB burst 612 adjacent to an SSB burst 614 with the second puncture pattern. In some implementations, the first SSB 510 is transmitted in a first SSB burst set 626 and the second SSB 520 is transmitted in a second SSB burst set 628. A time offset 630 between a start of the first SSB burst set 626 and the second SSB burst set 628 may be equal to half of a periodicity of the first SSB burst set and the second SSB burst set. For example, a default periodicity for a cell search may be 20 ms for both of the first SSB burst set and the second SSB burst set. As another example, a default periodicity for a cell search may be 40 ms for both of the first SSB burst set and the second SSB burst set.

In some implementations, the first SSB 710 has a different circulant bit offset for bit-to-RE mapping than the second SSB 720 such that the first set of resource blocks 730 includes different bits than the second set of resource blocks 730. The first set of resource blocks 730 may be the same as the second set of resource blocks 730. In some implementations, the first SSB 710 is transmitted in a first SSB burst set 626 with a first circulant bit offset and the second SSB 720 is transmitted in a second SSB burst set 628 with a second circulant bit offset. A default periodicity for a cell search of the first SSB burst set and the second SSB burst set may be 20 ms. In some implementations, a DMRS sequence indicates the circulant bit offset value for bit-to-RE mapping.

At block 1130, the method 1100 may optionally include transmitting at least two repetitions of a SIB1 PDSCH in at least two consecutive slots on the bandwidth. In some implementations, for example, base station 102, the TX processor 316, or the controller/processor 375 may execute the PBCH puncturing component 120 or the transmitter component 852 to transmit the at least two repetitions of a SIB1 PDSCH in at least two consecutive slots on the bandwidth. In some implementations, repetition of the SIB1 PDSCH is indicated by one or more fields of the PBCH or a SIB1 PDCCH. In some implementations, the at least two repetitions of the SIB1 PDSCH have different redundancy versions. For example, the different redundancy versions may improve decoding of the SIB1 PDSCH in cases where the SIB1 PDSCH is punctured or transmitted with a high coding rate. Accordingly, the base station 102, the TX processor 316, or the controller/processor 375 executing the PBCH puncturing component 120 or the transmitter component 852 may provide means for transmitting at least two repetitions of a SIB1 PDSCH in at least two consecutive slots on the bandwidth.

The following provides an overview of aspects of the present disclosure:

Aspect 1: A method of wireless communication, comprising: receiving a first synchronization signal block (SSB) on a bandwidth less than 5 MHz, the first SSB including a physical broadcast channel (PBCH) having a first set of resource blocks that have been punctured; and receiving a second SSB on the bandwidth, the second SSB including the PBCH having a second set of resource blocks that have been punctured.

Aspect 2: The method of Aspect 1, further comprising combining the PBCH from the first SSB and the PBCH from the second SSB to decode the PBCH.

Aspect 3: The method of

Aspect

1 or 2, wherein the first SSB follows a different puncture pattern than the second SSB such that the first set of resource blocks and the second set of resource blocks are different.

Aspect 4: The method of Aspect 3, wherein the first SSB is received in a first portion of an SSB burst set and the second SSB is received in a second portion of the SSB burst set.

Aspect 5: The method of

Aspect

3 or 4, wherein the first puncture pattern is in an SSB burst adjacent to an SSB burst with the second puncture pattern.

Aspect 6: The method of Aspect 3, wherein the first SSB is received in a first SSB burst set and the second SSB is received in a second SSB burst set.

Aspect 7: The method of Aspect 6, wherein a time offset between a start of the first SSB burst set and the second SSB burst set is equal to half of a periodicity of the first SSB burst set and the second SSB burst set.

Aspect 8: The method of Aspect 7, wherein a default periodicity for a cell search is 20 ms for both of the first SSB burst set and the second SSB burst set.

Aspect 9: The method of Aspect 7, wherein a default periodicity for a cell search is 40 ms for both of the first SSB burst set and the second SSB burst set.

Aspect 10: The method of

Aspect

1 or 2, wherein the first SSB has a different circulant bit offset for bit-to-RE mapping than the second SSB such that the first set of resource blocks includes different bits than the second set of resource blocks.

Aspect 11: The method of Aspect 10, wherein the first SSB is received in a first SSB burst set with a first circulant bit offset and the second SSB is received in a second SSB burst set with a second circulant bit offset.

Aspect 12: The method of Aspect 11, wherein a default periodicity for a cell search of the first SSB burst set and the second SSB burst set is 20 ms.

Aspect 13: The method of

Aspect

11 or 12, wherein a demodulation reference signal (DMRS) sequence indicates the circulant bit offset value for bit-to-RE mapping.

Aspect 14: The method of any of Aspects 1-13, further comprising receiving at least two repetitions of a first system information block (SIB1) physical downlink shared channel (PDSCH) in at least two consecutive slots on the bandwidth.

Aspect 15: The method of Aspect 14, wherein repetition of the SIB1 PDSCH is indicated by one or more fields of the PBCH or a SIB1 physical downlink control channel (PDCCH) .

Aspect 16: The method of Aspect 14 or 15, wherein the at least two repetitions of the SIB1 PDSCH have different redundancy versions.

Aspect 17: An apparatus for wireless communication, comprising: a transceiver; a memory storing computer-executable instructions; and a processor coupled with the transceiver and the memory and configured to execute the computer-executable instructions to perform the method of any of Aspects 1-16.

Aspect 18: An apparatus for wireless communication, comprising: means for performing the method of any of Aspects 1-16.

Aspect 19: A non-transitory computer-readable medium storing computer executable code, the code when executed by a processor causes the processor to perform the method of any of Aspects 1-16.

Aspect 20: A method of wireless communication, comprising: transmitting a first synchronization signal block (SSB) including a physical broadcast channel (PBCH) on a bandwidth less than 5 MHz, wherein transmitting the first SSB includes puncturing a first set of resource blocks of the PBCH; and transmitting a second SSB including the PBCH on the bandwidth, wherein transmitting the second SSB includes puncturing a second set of resource blocks of the PBCH.

Aspect 21: The method of Aspect 20, wherein the first SSB follows a different puncture pattern than the second SSB such that the first set of resource blocks and the second set of resource blocks are different.

Aspect 22: The method of Aspect 21, wherein the first SSB is transmitted in a first portion of an SSB burst set and the second SSB is transmitted in a second portion of the SSB burst set.

Aspect 23: The method of Aspect 21 or 22, wherein the first puncture pattern is in a burst set adjacent to a burst set with the second puncture pattern.

Aspect 24: The method of Aspect 21, wherein the first SSB is transmitted in a first SSB burst set and the second SSB is transmitted in a second SSB burst set.

Aspect 25: The method of Aspect 24, wherein a time offset between a start of the first SSB burst set and the second SSB burst set is equal to half of a periodicity of the first SSB burst set and the second SSB burst set.

Aspect 26: The method of Aspect 25, wherein the periodicity of the first SSB burst set and the second SSB burst set is 20 ms.

Aspect 27: The method of Aspect 25, wherein the periodicity of the first SSB burst set and the second SSB burst set is 40 ms.

Aspect 28: The method of Aspect 20, wherein the first SSB has a different circulant bit offset for bit-to-RE mapping than the second SSB such that the first set of resource blocks includes different bits than the second set of resource blocks.

Aspect 29: The method of Aspect 28, wherein the first SSB is transmitted in a first SSB burst set with a first circulant bit offset and the second SSB is transmitted in a second SSB burst set with a second circulant bit offset.

Aspect 30: The method of Aspect 29, wherein a periodicity of the first SSB burst set and the second SSB burst set is 20 ms.

Aspect 31: The method of Aspect 29, wherein a demodulation reference signal (DMRS) sequence indicates the circulant bit offset value for bit-to-RE mapping.

Aspect 32: The method of any of Aspects 20-31, further comprising transmitting at least two repetitions of a first system information block (SIB1) physical downlink shared channel (PDSCH) in at least two consecutive slots on the bandwidth.

Aspect 33: The method of Aspect 32, wherein repetition of the SIB1 PDSCH is indicated by one or more fields of the PBCH or a SIB1 physical downlink control channel (PDCCH) .

Aspect 34: The method of Aspect 29 or 30, wherein the at least two repetitions of the SIB1 PDSCH have different redundancy versions.

Aspect 35: An apparatus for wireless communication, comprising: a transceiver; a memory storing computer-executable instructions; and a processor coupled with the transceiver and the memory and configured to execute the computer-executable instructions to perform the method of any of Aspects 20-34.

Aspect 36: An apparatus for wireless communication, comprising: means for performing the method of any of Aspects 20-34.

Aspect 37: A non-transitory computer-readable medium storing computer executable code, the code when executed by a processor causes the processor to perform the method of any of Aspects 20-34.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

The various illustrative logics, logical blocks, modules, circuits and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system.

The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single-or multi-chip processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular processes and methods may be performed by circuitry that is specific to a given function.

In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage media for execution by, or to control the operation of, data processing apparatus.

If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. The processes of a method or algorithm disclosed herein may be implemented in a processor-executable software module which may reside on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program from one place to another. A storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer. Also, any connection can be properly termed a computer-readable medium. Disk and disc, as used herein, includes compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk, and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine readable medium and computer-readable medium, which may be incorporated into a computer program product.

Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

Additionally, a person having ordinary skill in the art will readily appreciate, the terms “upper” and “lower” are sometimes used for ease of describing the figures, and indicate relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of any device as implemented.

Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

Claims

An apparatus for wireless communication, comprising:

a transceiver;

a memory storing computer-executable instructions; and

at least one processor coupled with the transceiver and the memory and configured to execute the computer-executable instructions to:

receive a first synchronization signal block (SSB) on a bandwidth less than 5 MHz, the first SSB including a physical broadcast channel (PBCH) having a first set of resource blocks that have been punctured; and

receive a second SSB on the bandwidth, the second SSB including the PBCH having a second set of resource blocks that have been punctured.
The apparatus of claim 1, wherein the at least one processor is configured to combine the PBCH from the first SSB and the PBCH from the second SSB to decode the PBCH.
The apparatus of claim 1, wherein the first SSB follows a different puncture pattern than the second SSB such that the first set of resource blocks and the second set of resource blocks are different.
The apparatus of claim 3, wherein the first SSB is received in a first portion of an SSB burst set and the second SSB is received in a second portion of the SSB burst set.
The apparatus of claim 3, wherein the first SSB with a first puncture pattern is in a first SSB burst adjacent to a second SSB burst including the second SSB with a second puncture pattern.
The apparatus of claim 3, wherein the first SSB is received in a first SSB burst set and the second SSB is received in a second SSB burst set.
The apparatus of claim 6, wherein a time offset between a start of the first SSB burst set and the second SSB burst set is equal to half of a periodicity of the first SSB burst set and the second SSB burst set.
The apparatus of claim 7, wherein a default periodicity for a cell search is 20 ms for both of the first SSB burst set and the second SSB burst set.
The apparatus of claim 7, wherein a default periodicity for a cell search is 40 ms for both of the first SSB burst set and the second SSB burst set.
The apparatus of claim 1, wherein the first SSB has a different circulant bit offset for bit-to-RE mapping than the second SSB such that the first set of resource blocks includes different bits than the second set of resource blocks.
The apparatus of claim 10, wherein the first SSB is received in a first SSB burst set with a first circulant bit offset and the second SSB is received in a second SSB burst set with a second circulant bit offset.
The apparatus of claim 11, wherein a default periodicity for a cell search of the first SSB burst set and the second SSB burst set is 20 ms.
The apparatus of claim 11, wherein a demodulation reference signal (DMRS) sequence indicates the circulant bit offset value for bit-to-RE mapping.
An apparatus for wireless communication, comprising:

a transceiver;

a memory storing computer-executable instructions; and

at least one processor coupled with the transceiver and the memory and configured to execute the computer-executable instructions to:

transmit a first synchronization signal block (SSB) including a physical broadcast channel (PBCH) on a bandwidth less than 5 MHz, wherein transmitting the first SSB includes puncturing a first set of resource blocks of the PBCH; and

transmit a second SSB including the PBCH on the bandwidth, wherein transmitting the second SSB includes puncturing a second set of resource blocks of the PBCH.
The apparatus of claim 14, wherein the first SSB follows a different puncture pattern than the second SSB such that the first set of resource blocks and the second set of resource blocks are different.
The apparatus of claim 15, wherein the first SSB is transmitted in a first portion of an SSB burst set and the second SSB is transmitted in a second portion of the SSB burst set.
The apparatus of claim 16, wherein the first SSB with a first puncture pattern is in a first SSB burst adjacent to a second SSB burst including the second SSB with a second puncture pattern.
The apparatus of claim 15, wherein the first SSB is transmitted in a first SSB burst set and the second SSB is transmitted in a second SSB burst set.
The apparatus of claim 18, wherein a time offset between a start of the first SSB burst set and the second SSB burst set is equal to half of a periodicity of the first SSB burst set and the second SSB burst set.
The apparatus of claim 19, wherein a default periodicity for a cell search is 20 ms for both of the first SSB burst set and the second SSB burst set.
The apparatus of claim 19, wherein a default periodicity for a cell search is 40 ms for both of the first SSB burst set and the second SSB burst set.
The apparatus of claim 14, wherein the first SSB has a different circulant bit offset for bit-to-RE mapping than the second SSB such that the first set of resource blocks includes different bits than the second set of resource blocks.
The apparatus of claim 22, wherein the first SSB is transmitted in a first SSB burst set with a first circulant bit offset and the second SSB is transmitted in a second SSB burst set with a second circulant bit offset.
The apparatus of claim 23, wherein a default periodicity for a cell search of the first SSB burst set and the second SSB burst set is 20 ms.
The apparatus of claim 23, wherein a demodulation reference signal (DMRS) sequence indicates the circulant bit offset value for bit-to-RE mapping.
A method of wireless communication, comprising:

receiving a first synchronization signal block (SSB) on a bandwidth less than 5 MHz, the first SSB including a physical broadcast channel (PBCH) having a first set of resource blocks that have been punctured; and

receiving a second SSB on the bandwidth, the second SSB including the PBCH having a second set of resource blocks that have been punctured.
The method of claim 26, further comprising combining the PBCH from the first SSB and the PBCH from the second SSB to decode the PBCH.
The method of claim 26, wherein the first SSB follows a different puncture pattern than the second SSB such that the first set of resource blocks and the second set of resource blocks are different.
The method of claim 26, wherein the first SSB has a different circulant bit offset for bit-to-RE mapping than the second SSB such that the first set of resource blocks includes different bits than the second set of resource blocks.
A method of wireless communication, comprising:

transmitting a first synchronization signal block (SSB) including a physical broadcast channel (PBCH) on a bandwidth less than 5 MHz, wherein transmitting the first SSB includes puncturing a first set of resource blocks of the PBCH; and

transmitting a second SSB including the PBCH on the bandwidth, wherein transmitting the second SSB includes puncturing a second set of resource blocks of the PBCH.