Fast initial acquisition by transmitting non-orthogonal synchronization signal blocks in 5G New Radio

Abstract

Systems and methods for initial acquisition in an NR system are described. The UE receives time and frequency superimposed SSBs from a gNB. If the PSS and SSS of each SSB do not depend on the block index of the SSB, the UE receives an additional reference signal scrambled by the beam index of the SSB and uses the reference signal to distinguish the SSB. The reference signal is frequency domain multiplexed (FDMed) within the null subcarrier region of the SSB or outside the SSB. If the PSS and SSS of each SSB are scrambled using the block index, the UE performs the following operations: separate PBCH measurements, iteratively identify the block index associated with the DMRS of the PBCH with the highest L1‑RSRP level measurement, decode and reconstruct the PBCH, and subtract the reconstructed PBCH from the SSB, and then transmit an indication of the PBCH with the highest L1‑RSRP level measurement to the gNB.

Description

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62 / 720020, filed on August 20, 2018, which is incorporated herein by reference in its entirety. Technical Field

[0002] Embodiments relate to radio access networks (RANs). Some embodiments relate to cellular networks, including 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), 4th Generation (4G) and 5th Generation (5G) New Radio (NR) (or Next Generation (NG)) networks. Some embodiments relate to initial acquisition in NR systems. Background Art

[0003] Due to the increase in the number and types of user equipment (UE) using network resources and the increase in the amount of data and bandwidth used by various applications (such as video streaming) operating on these UEs, the use of various types of systems has also increased. Enhanced bandwidth, latency, and data rates can be used to meet the increasing demand for network resources. The next generation of wireless communication systems, 5G or NR, will provide ubiquitous connectivity and access to information, as well as the ability for various users and applications to share data. NR is expected to be a unified framework designed to meet very different and sometimes conflicting performance standards and services. In general, NR will evolve based on 3GPP LTE Advanced technology and other enhanced radio access technologies (RATs) to achieve seamless wireless connectivity solutions. However, as with the emergence of any new technology, many problems arise with the introduction and use of such technologies. In this case, the extension of the initial acquisition time due to beamforming in the NR system can be problematic. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] In the drawings, which are not necessarily drawn to scale, like numbers may describe similar components in different views. Like numbers with different letter suffixes may represent different instances of similar components. The accompanying drawings generally illustrate various aspects described in this document by way of example and not by way of limitation.

[0005] Figure 1 A combined communication system according to some embodiments is shown.

[0006] Figure 2 A block diagram of a communication device according to some embodiments is shown.

[0007] Figure 3 An example of superposition of non-orthogonal system signal blocks (SSBs) is shown in accordance with some embodiments.

[0008] Figure 4 Examples of SSB regions according to some embodiments are shown.

[0009] Figure 5 An example of a flow chart for separating TX wavenumber measurements is shown in accordance with some embodiments. DETAILED DESCRIPTION

[0010] The following description and drawings sufficiently illustrate specific aspects to enable those skilled in the art to practice these aspects. Other aspects may incorporate structural changes, logical changes, electrical changes, process changes, and other changes.

[0011] Portions and features of some aspects may be included in, or substituted for, portions and features of other aspects.Aspects set forth in the claims encompass all available equivalents of those claims.

[0012] Figure 1 A combined communication system according to some embodiments is shown. System 100 includes 3GPP LTE / 4G and NG network functions. The network functions can be implemented as discrete network elements on dedicated hardware, software instances running on dedicated hardware, or virtualized functions instantiated on an appropriate platform (e.g., dedicated hardware or cloud infrastructure).

[0013] The Evolved Packet Core (EPC) of the LTE / 4G network contains protocols and reference points defined for each entity. These core network (CN) entities may include a Mobility Management Entity (MME) 122, a Serving Gateway (S-GW) 124, and a Paging Gateway (P-GW) 126.

[0014] In NG networks, the control plane and user plane may be separate, which may allow independent scaling and allocation of resources for each plane. UE 102 may be connected to an access network or random access network (RAN) 110 and / or may be connected to an NG-RAN 130 (gNB) or an access and mobility function (AMF) 142. RAN 110 may be an eNB or a general non-3GPP access point, such as an access point for Wi-Fi. The NG core network may include multiple network functions in addition to AMF 112. UE 102 may generate, encode, and possibly encrypt uplink transmissions to RAN 110 and / or gNB 130, and decode (and decrypt) downlink transmissions from RAN 110 and / or gNB 130 (where the reverse is true for RAN 110 / gNB 130).

[0015] The network functions may include a user plane function (UPF) 146, a session management function (SMF) 144, a policy control function (PCF) 132, an application function (AF) 148, an authentication server function (AUSF) 152, and a user data management (UDM) 128. The various elements are connected by Figure 1 NG reference point connections shown.

[0016] AMF 142 may provide UE-based authentication, authorization, mobility management, etc. AMF 142 may be independent of access technology. SMF 144 may be responsible for session management and assigning IP addresses to UE 102. SMF 144 may also select and control UPF 146 for data transmission. SMF 144 may be associated with a single session of UE 102 or multiple sessions of UE 102. That is, UE 102 may have multiple 5G sessions. A different SMF may be assigned to each session. Using different SMFs allows each session to be managed separately. Therefore, the functions of each session may be independent of each other. UPF 126 may be connected to a data network with which UE 102 may communicate, and UE 102 transmits uplink data to the data network or receives downlink data from the data network.

[0017] AF 148 may provide information about packet flows to PCF 132, which is responsible for policy control to support the desired QoS. PCF 132 may set mobility and session management policies for UE 102. To this end, PCF 132 may use packet flow information to determine appropriate policies for correct operation of AMF 142 and SMF 144. AUSF 152 may store data for UE authentication. UDM 128 may similarly store UE subscription data.

[0018] The gNB 130 may be a standalone gNB or a non-standalone gNB, for example, operating in dual connectivity (DC) mode as an enhancer controlled by the eNB 110 via an X2 or Xn interface. At least some of the functionality of the EPC and NG CN may be shared (alternatively, separate components may be used for each of the combined components shown). The eNB 110 may be connected to the MME 122 of the EPC via an S1 interface and to the SGW 124 of the EPC 120 via an S1-U interface. The MME 122 may be connected to the HSS 128 via an S6a interface, and the UDM may be connected to the AMF 142 via an N8 interface. The SGW 124 may be connected to the PGW 126 via an S5 interface (connected to the control plane PGW-C via S5-C and to the user plane PGW-U via S5-U). The PGW 126 may serve as an IP anchor for data passing through the Internet.

[0019] As above, NG CN may include AMF 142, SMF 144, UPF 146, etc. eNB 110 and gNB 130 may transmit data with SGW 124 of EPC 120 and UPF 146 of NG CN. If the N26 interface is supported by EPC 120, MME 122 and AMF 142 may be connected via the N26 interface to provide control information therebetween. In some embodiments, when gNB 130 is an independent gNB, 5G CN and EPC 120 may be connected via the N26 interface.

[0020] Figure 2 A block diagram of a communication device according to some embodiments is shown. In some embodiments, the communication device may be a UE (including loT devices and NB-IoT devices), an eNB, a gNB, or other devices used in a network environment. For example, the communication device 200 may be a dedicated computer, a personal or laptop computer (PC), a tablet, a mobile phone, a smart phone, a network router, a switch or a bridge, or any machine capable of executing instructions (in sequence or otherwise) that specify actions to be taken by the machine. In some embodiments, the communication device 200 may be embedded in other non-communication-based devices such as vehicles and appliances.

[0021] Examples as described herein may include a logical component or multiple components, modules or mechanisms, or may operate on a logical component or multiple components, modules or mechanisms. Modules and components are tangible entities (e.g., hardware) that can perform specified operations and can be configured or arranged in some way. In one example, a circuit may be arranged as a module in a specified manner (e.g., internally or relative to an external entity such as other circuits). In one example, all or part of one or more computer systems (e.g., independent computer systems, client computer systems, or server computer systems) or one or more hardware processors may be configured by firmware or software (e.g., instructions, application parts, or applications) to operate to perform a specified operation of the module. In one example, the software may reside on a machine-readable medium. In one example, the software, when executed by the underlying hardware of the module, causes the hardware to perform a specified operation.

[0022] Thus, the term "module" (and "component") should be understood to encompass tangible entities, i.e., entities that are physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transiently) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operations described herein. Considering an example where a module is temporarily configured, each module need not be instantiated at any one time. For example, if a module includes a general-purpose hardware processor configured using software, the general-purpose hardware processor may be configured into corresponding different modules at different times. The software may configure the hardware processor accordingly, for example, to constitute a particular module at one instance in time and to constitute a different module at a different instance in time.

[0023] The communication device 200 may include a hardware processor 202 (e.g., a central processing unit (CPU), a GPU, a hardware processor core, or any combination thereof), a main memory 204, and a static memory 206, some or all of which may communicate with each other via an interconnect (e.g., a bus) 208. The main memory 204 may include any or all of a removable storage device and a non-removable storage device, a volatile memory, or a non-volatile memory. The communication device 200 may also include a display unit 210 such as a video display, a mixed digital and alphanumeric input device 212 (e.g., a keyboard), and a user interface (UI) navigation device 214 (e.g., a mouse). In one example, the display unit 210, the input device 212, and the UI navigation device 214 may be a touch screen display. The communication device 200 may additionally include a storage device (e.g., a drive unit) 216, a signal generating device 218 (e.g., a speaker), a network interface device 220, and one or more sensors, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or other sensors. The communication device 200 may also include an output controller, such as a serial (e.g., Universal Serial Bus (USB)) connection, a parallel connection, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.).

[0024] The storage device 216 may include a non-transitory machine-readable medium 222 (hereinafter referred to as a machine-readable medium) on which one or more sets of data structures or instructions 224 (e.g., software) embodied or utilized by any one or more of the techniques or functions described herein are stored. The instructions 224 may also reside successfully or at least partially within the main memory 204, within the static memory 206, and / or within the hardware processor 202 during execution of these instructions by the communication device 200. Although the machine-readable medium 222 is shown as a single medium, the term "machine-readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database and / or associated caches and servers) configured to store one or more instructions 224.

[0025] The term "machine-readable medium" may include any medium capable of storing, encoding, or carrying instructions for execution by the communication device 200 and causing the communication device 200 to perform any one or more of the techniques of the present disclosure, or capable of storing, encoding, or carrying data structures used by or associated with such instructions. Non-limiting examples of machine-readable media may include solid-state memory, and optical and magnetic media. Specific examples of machine-readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks, magneto-optical disks; random access memory (RAM); and CD-ROM and DVD-ROM disks.

[0026] The instructions 224 may also be transmitted or received in a communication network via a network interface device 220 using a transmission medium 226, which utilizes any of a plurality of transmission protocols (e.g., frame relay, Internet Protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Exemplary communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), a mobile phone network (e.g., a cellular network), a plain old telephone (POTS) network, and a wireless data network. Communications in the network may include one or more different protocols, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards (referred to as Wi-Fi), the IEEE 802.16 family of standards (referred to as WiMax), the IEEE 802.15.4 family of standards, the Long Term Evolution (LTE) family of standards, the Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, NG / NR standards, and the like. In one example, the network interface device 220 may include one or more physical jacks (eg, Ethernet jacks, coaxial jacks, or telephone jacks) or one or more antennas to connect to the transmission medium 226 .

[0027] The communication device 200 may be an IoT device (also referred to as a “machine type communication device” or “MTC device”), a narrowband IoT (NB-IoT) device, or a non-IoT device (e.g., a smartphone, a vehicle UE), any of which may be connected to a wireless communication network via a wireless communication network. Figure 1 The eNB or gNB shown communicates with the core network. The communication device 200 may be an autonomous or semi-autonomous device that communicates with other communication devices and a wider network (such as the Internet) to perform one or more functions (such as sensing or control, etc.). If the communication device 200 is an IoT device, in some embodiments, the communication device 200 may be limited in memory, size, or functionality, allowing a larger number of devices to be deployed at a similar cost to a smaller number of larger devices. In some embodiments, the communication device 200 may be a virtual device, such as an application on a smartphone or other computing device.

[0028] As described above, the RA (eNB or gNB) may use beamforming to allow the LIE to perform an initial acquisition process to connect to the radio access network (cell), as well as for reference signal measurements for mobility purposes - switching when the LIE is in connected mode or idle mode. Beamforming in NR systems has been significantly enhanced compared to 4G LTE systems. The NR system introduces additional search dimensions for initial acquisition, which include a transmitter (TX) beam dimension for the sub-6 GHz range (frequency range one (FR1)) and a TX beam + receiver (RX) beam dimension for the >6 GHz range (frequency range two (FR2)). The initial acquisition or switching process in the NR system may involve the UE detecting a synchronization signal block (SSB). The SSB contains a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH) demodulation reference signal (DMRS) and a PBCH payload.

[0029] During initial acquisition, the UE can perform initial synchronization by detecting the PSS and SSS to obtain the cell identity and frame timing. The PSS can provide slot timing and physical layer ID; the SSS can provide the physical layer cell identity group number, physical layer cell ID, cyclic prefix length, FDD or TDD determination for radio frame timing detection.

[0030] The UE may then obtain system information during reception of the PBCH in the SSB, which may carry a master information block (MIB) and, in some cases, a system information block (SIB) for the cell. The UE may obtain random access procedure configuration information from the PBCH. The PSS and SSS may each be 1 symbol, while the PBCH may be 2 symbols. One or more SSBs may be transmitted in an SSB burst, which itself is transmitted within an SS burst set of one or more SSB bursts containing Sms. The periodicity of the SS burst set may be, for example, 20ms. The number of possible candidate SSB positions within the SS burst set may depend on the frequency: 4 positions up to 3GHz, 8 positions from 3GHz to 6GHz, and 64 positions from 6GHz to 52.6GHz.

[0031] After obtaining the random access procedure configuration information, the LIE may perform a random access procedure. The random access procedure may include the UE initially transmitting a physical random access channel (PRACH) (Msg-1) and attempting to receive a random access response (RAR) (Msg-2) in a physical downlink shared channel (PDSCH). The PRACH may carry a random access preamble from the UE to the RAN. The PRACH may use a random access radio network temporary identifier (RA-RNTI) and a selected preamble index. The PRACH may be sent at a time and frequency position determined according to the RACH parameters in SIB2.

[0032] The preamble can be generated using a Zadoff Chu (ZC) sequence. The preamble (if received by the RAN) can adjust the uplink timing for message transmission by the UE in addition to other parameters. The 5G NR random access preamble supports two different sequence lengths with various format configurations (Format 0, Format 1, Format 2, Format 3, Format Al, Format A2, Format A3, Format Bl, Format B2, Format B3, Format B4, Format CO, Format Cl). 839 Long preamble sequences are used by four preamble formats (0-3), which are designed for large cell deployment in FR1 and have a subcarrier spacing of 1.25KHz or 5KHz; 139 Short preamble sequences are used by nine preamble formats (AC), which are designed for small cell deployment / beam scanning in FR1 with a subcarrier spacing of 15KHz or 30KHz and in the rnmwave (FR2) range with a subcarrier spacing of 60KHz or 120KHz. 64 preambles can be defined in each time-frequency PRACH occasion.

[0033] If the UE does not receive the RAR within the predefined (or configured) time window, the UE may retransmit the PRACH with increased power until the UE receives the RAR. If the UE receives the RAR, the UE may transmit the Msg-3 (RRC connection request) using the resources indicated by the RAR, and may receive the Msg-4 (contention resolution, carrying an acknowledgment (ACK) + contention resolution ID (GRID)), at which point the initial acquisition process ends.

[0034] However, before participating in the random access procedure, the UE may try to acquire the best TX beam (e.g., the TX beam with the highest received signal strength indicator (RRSI)) from the gNB. To help the UE acquire the best TX beam from the gNB side, the gNB may scan the TX beams by time-division multiplexing SSBs associated with SSB indices specific to different TX beams within an SSB burst as described above. As described above, depending on the frequency range, the number of TX beams may be 4, 8, or 64, and the SSB burst may be repeated within a predefined periodicity of, for example, 5, 10, 20, or 80 ms.

[0035] For time-division multiplexed SSBs within an SSB burst, the PSS and SSS have the same transmission waveform between SSBs. This is because the PSS and SSS are determined by the physical cell ID, which is the same in each transmission. However, the PBCH DMRS and PBCH payload subcarriers are different transmission waveforms because the PBCH DMRS and PBCH are determined by the SSB block index, which is different for different SSBs.

[0036] As the gNB scans an increasing number of TX beams, the length of the SSB burst is extended to include more time-division multiplexed SSBs. This may therefore extend the initial acquisition time. Although the SSBs associated with different TX beams can be frequency domain multiplexed simultaneously using multiple antenna panels that can operate simultaneously, the UE may re-adjust the RX center carrier frequency for different SSB frequency locations, which is also time consuming.

[0037] Alternatively or in addition, multiple antenna panels or transmission points (TRPs) of a gNB may be used to steer multiple non-orthogonal SSBs simultaneously. Each non-orthogonal SSB may be associated with a different TX beam. Each TX beam may have a different TX beam index. The gNB may also overlay steered SSBs on the same time and frequency allocation, i.e., the TX beams may completely overlap in time and frequency (if not in space). Therefore, to speed up TX beam acquisition for NR initial acquisition, the gNB may transmit time-frequency overlapping SSB blocks by simultaneously transmitting different SSBs from different antenna panels of the same gNB. This may allow the UE to simultaneously measure multiple TX beams from the gNB without retuning the center frequency, enabling faster initial acquisition even as the number of gNB TX beams increases.

[0038] In some embodiments, the PSS / SSS within the superimposed SSB may be cell ID dependent but not TX beam index dependent. This may allow the PSS / SSS to be omni-directional antenna-like propagated. Using the same PSS / SSS waveform regardless of the beam may also reduce the TX beam search space for the UE to perform PSS / SSS based cell ID acquisition. Figure 3 An example of superposition of non-orthogonal system SSBs according to some embodiments is shown. As shown, four TRPs provide four SSBs (SSB1, SSB2, SSB3, SSB4) in different directions simultaneously. Although the SSBs are shown as symmetrically / equidistantly spaced (approximately 90°), in other embodiments, the TRPs may be positioned to provide SSBs in an asymmetric manner. For example, if a UE is unlikely to be within a particular angular range, the coverage of the SSBs for that angular range may be minimized.

[0039] In some implementations, the PBCH within the superimposed SSBs can be scrambled using the same SSB block index. This can be similar to PSS / SSS to make the PBCH omni-directional antenna-like propagation, and can also reduce the TX beam search space for UE to perform PBCH acquisition and time slot timing acquisition.

[0040] In order to distinguish SSB in this case, a third synchronization signal (SS) may be introduced. The third SS may depend on the TX beam and may facilitate the UE to separate the measurements of different TX beams. Figure 4 An example of an SSB region according to some embodiments is shown. Figure 4As shown, the additional beam index-dependent third SS 402 may be disposed within one or more of the SSB null subcarrier regions 404. As shown, the SSB null subcarrier region 404 may be limited to the SSB 400 (not extending outside the bandwidth of the SSB 400). The null subcarrier region 404 does not carry any other signal of the SSB 400: PSS, SSS, or PBCH. As shown, the null subcarrier region 404 (and therefore the third SS 402) may exist at one or more frequencies above and below the PSS of the SSB 400, as well as at frequencies between the SSS and the surrounding PBCH.

[0041] The third SS 402 may be, for example, a channel state information reference signal (CSI-RS) allocated within a null subcarrier region 404 within an SSB 400. Thus, the beam index-specific third SS 404 within the superimposed SSB 400 may be frequency domain multiplexed (FDMed) to avoid cross interference between the superimposed SSBs 400. Although shown as extending through each of the null subcarrier regions 404, different portions of one or more of the null subcarrier regions 404 may carry the beam index-specific third SS 404. The beam index-specific third SS 404 may contain different information depending on the beam index, such as being code division multiplexed, and / or may be set in different frequency locations of the SSB 400 depending on the beam index. For example, SSB1 may transmit one or more third SSs 402 in region "a" at a frequency higher than the PSS in the SSB 400, while SSB2 may transmit one or more third SSs 402 in region "b" at a frequency higher than the PSS in the SSB 400, and so on. The third SS 402 may be the same or different in each region. Alternatively, the third SS 404 may be located in an OFDM symbol other than the SSB. For example, the third SS 404 may be located in a regular CSI-RS symbol.

[0042] In other embodiments, instead of scrambling the PBCH of different SSBs with the same SSB block index, the PBCH within the superimposed SSBs may be scrambled with different SSB block indices. In this case, different PBCH sequences from the superimposed SSBs may collide with each other. To address this issue, the UE RX may apply a successive interference cancellation (SIC) algorithm to the collided PBCH of the received SSBs in order to separate the measurements of different TX beams.

[0043] Furthermore, considering that the SSB block index defined in 3GPP Release 15 contains both beam index information and SSB block timing information, the two pieces of these two pieces of information can be separated by the gNB. After separation, the gNB can use only the beam index to scramble the PBCH subcarriers, while the same timing information is used for the superimposed SSB. Different SSB block indices associated with the superimposed SSB can be mapped to the same ODFM symbol index within a downlink (DL) frame.

[0044] In addition, the number of superimposed SSBs can be predefined in the standard or indicated at run time by the network to the UE. For example, the number of superimposed SSBs can be indicated based on LTE subcarriers in E-IJTRA (a / k / a LTE)-NR dual connectivity (EN-DC) mode. This can help the UE stop the SIC algorithm iteration on the RX side in advance.

[0045] Figure 5 An example of a flow chart for separating TX wave number measurements according to some embodiments is shown. As described above, the UE uses this flow chart when the gNB scrambles the superimposed SSBs by different block indices. At operation 502, the UE detects the timing and physical cell ID of the superimposed SSB based on the correlation of the PSS and SSS. There is no PSS / SSS co-interference because all gNB TX beams within the superimposed SSB contain the same PSS / SSS signal. As described above, the UE can use the common PSS and SSS of the superimposed SSB to determine the timing and physical cell ID.

[0046] The UE may then separate the different PBCH signals (in order to measure the beam quality after separation), where each different PBCH signal is transmitted by a single gNB TX beam within the received superimposed SSB signal. This separation may be based on the SIC algorithm. The remaining operations involve iterations of separation and determination.

[0047] After determining the timing and physical cell ID, the UE may extract the PBCH subcarriers from the received SSBs at operation 504. In some implementations, the time domain in-phase and quadrature-phase (IQ) samples of each received superimposed SSB are converted to the frequency domain and the PBCH subcarriers (SC) are extracted.

[0048] The UE may then measure the DMRS at operation 506. Specifically, in some implementations, the UE may measure the L1 received signal reference power (RSRP) of the PBCH DMRS for all remaining SSB indices within the index set.

[0049] After obtaining the measurement, the UE may select the SSB index with the strongest LI-RSRP (highest LI-RSRP level) measurement through multiple iterations at operation 508. Lower LI-RSRP measurements may be inaccurate due to interference, so the wave number index with the strongest LI-RSRP is of interest.

[0050] The gNB may indicate the number of superimposed SSBs to the UE via higher layer signaling such as a radio resource control (RRC) signal or gNB assistance information. The UE may limit the number of superimposed SSBs based on the number of superimposed SSBs indicated by the higher layer signaling. Figure 5 The maximum number of iterations is shown. The UE may then decode the PBCH associated with the selected SSB index having the strongest LI-RSRP measurement (also referred to as the highest LI-RSRP level measurement) at operation 510.

[0051] At operation 512, the UE may determine whether the PBCH cyclic redundancy check (CRC) passes using the checksum at the end of the PBCH payload. If the CRC does not pass, the UE may determine whether to terminate the SIC iteration at operation 514. If it passes, the UE may collect separate LI-RSRP measurements for different TX beams, each TX beam being associated with a different SSB index.

[0052] If the CRC passes, the UE may reconstruct the PBCH signal associated with the selected SSB index at operation 516. The UE may reproduce the strongest PBCH signal based on re-encoding the decoded information bits and further re-modulating the re-encoded information bits. This may produce a clean PBCH signal without contributions from other PBCH signals from other TX beams. The UE may then subtract the reconstructed PBCH signal from the received SSB at operation 518, and remove the selected SSB index from the index set at operation 520 before returning to operation 504. That is, the reconstructed clean PBCH signal that forms the strongest TX beam is subtracted from the received IQ samples, thereby removing the strongest interference in order to further measure weaker PBCH signals from other beams. As described above, the UE may limit the number of iterations to the number of superimposed SSBs indicated by higher layer signaling. Thus, using the SIC algorithm may allow measurement of each of the TX beams from the gNB while minimizing co-interference with conflicting PBCH signals.

[0053] The UE may provide an indication of the strongest SSB to the gNB. For example, during initial acquisition, the UE may send a PRACH preamble to the gNB in ​​a specific uplink resource corresponding to the downlink SSB where the best signal strength was detected. Alternatively, the UE may send an indication to the gNB in ​​a control channel.

[0054] Although an aspect has been described with reference to specific exemplary aspects, it is apparent that various modifications and changes may be made to these aspects without departing from the broader scope of the present disclosure. Accordingly, the specification and the drawings should be regarded as having illustrative rather than restrictive meanings. The drawings forming part of this document illustrate specific aspects of the practicable subject matter in an illustrative rather than restrictive manner. The aspects shown are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other aspects may be utilized and derived from the present disclosure, so that structural substitutions and logical substitutions and changes may be made without departing from the scope of the present disclosure. Therefore, this specific embodiment is not restrictive, and the scope of each aspect is limited only by the appended claims and the full scope of equivalents to which such claims are authorized.

[0055] The description abstract is provided to comply with 37 CFR § 1.72 (b), which requires the provision of a description abstract that will allow the reader to quickly ascertain the essence of the technical disclosure. The description abstract is provided with the understanding that the technical disclosure will not be used to interpret or limit the scope or meaning of the claims. In addition, in the above-described detailed description, it can be seen that various features are concentrated in a single aspect for the purpose of simplifying the disclosure. The disclosed method should not be interpreted as reflecting the intention that the claimed aspects require more features than those expressly recited in each claim. On the contrary, as reflected in the following claims, the inventive subject matter lies in less than all the features of a single disclosed aspect. Therefore, the following claims are hereby incorporated into the detailed description, with each claim existing independently as a separate aspect.

Claims

1. A device of a user equipment UE, the device comprising: One or more processors configured to: Decoding the time and frequency superimposed synchronization signal blocks SSB from the fifth generation NodeB, i.e. gNB, each SSB is associated with a different transmission beam from the gNB in ​​the spatial domain, and the SSBs each contain a physical broadcast channel PBCH; Determining a strongest SSB based on measurements of the PBCH for each SSB; encoding an indication of the strongest SSB for transmission to the gNB; For each SSB, decode the primary synchronization signal PSS and the secondary synchronization signal SSS, and For each SSB, a physical cell identifier ID and a cell timing are determined based on the PSS and the SSS, the PSS and the SSS of each SSB being scrambled using the same physical cell ID and not depending on a block index of the SSB.

2. The apparatus of claim 1 , wherein the one or more processors are further configured to: For each SSB, decoding an additional reference signal allocated in a null subcarrier region of the SSB, the additional reference signal being scrambled by a beam index of the SSB, and The indication is determined based on the additional reference signal.

3. The device according to claim 2, wherein: The additional reference signal is included in a plurality of the empty subcarrier regions of each SSB.

4. The device according to claim 2, wherein: The additional reference signal in each SSB is frequency domain multiplexed within the empty subcarrier region.

5. The device according to claim 2, wherein: The additional reference signal is set at a different frequency in each SSB.

6. The apparatus of claim 1, wherein the one or more processors are further configured to: For each SSB, an additional reference signal allocated outside the SSB is decoded, the additional reference signal being scrambled by a beam index of the SSB, and the indication is determined based on the additional reference signal.

7. A device of a user equipment UE, the device comprising: One or more processors configured to: Decoding the time and frequency superimposed synchronization signal blocks SSB from the fifth generation NodeB, i.e. gNB, each SSB is associated with a different transmission beam from the gNB in ​​the spatial domain, and the SSBs each contain a physical broadcast channel PBCH; Determining a strongest SSB based on measurements of the PBCH for each SSB; encoding an indication of the strongest SSB for transmission to the gNB; For each SSB, decode the primary synchronization signal PSS and the secondary synchronization signal SSS, and For each SSB, a physical cell identifier ID and a cell timing are determined based on the PSS and the SSS, and the PSS and the SSS of each SSB are scrambled using a block index of the SSB, wherein the SSB block index associated with the SSB is mapped to the same orthogonal frequency division multiplexing OFDM symbol index and time slot index within a downlink frame.

8. The apparatus of claim 7, wherein the one or more processors are further configured to: splitting the measurement of the PBCH of the SSB into measurements of the PBCH of each SSB, and Repeat the following steps over multiple iterations: identifying the block index associated with the demodulation reference signal DMRS of the PBCH having the highest reference signal received power L1-RSRP level measurement, After identifying the PBCH having the highest L1-RSRP level measurement, decoding the PBCH having the highest L1-RSRP level measurement, reconstructing the PBCH having the highest L1-RSRP level measurement, and The reconstructed PBCH is subtracted from the SSB.

9. The apparatus of claim 8, wherein the one or more processors are further configured to: When the cyclic redundancy check CRC of the decoded PBCH fails, the iteration is terminated early.

10. The apparatus of claim 8, wherein the one or more processors are further configured to: The number of superimposed SSBs is determined by higher layer signaling from the gNB.

11. The apparatus of claim 10, wherein the one or more processors are further configured to: The maximum number of iterations is limited to the number of superimposed SSBs based on the higher layer signaling.

12. A base station device, the device comprising: One or more processors configured to: A synchronization signal block SSB with encoding time and frequency superposition, each SSB is associated with a different transmission beam in the spatial domain, and each of the SSBs contains a physical broadcast channel PBCH; encoding the number of superimposed SSBs by higher layer signaling for transmission to a user equipment UE; decoding, from the UE, an indication of a strongest SSB received by the UE; A primary synchronization signal PSS and a secondary synchronization signal SSS are encoded for each SSB, and The PSS and the SSS of each SSB are scrambled using the same physical cell ID and do not depend on the block index of the SSB.

13. The device according to claim 12, wherein: The one or more processors are further configured to encode, for each SSB, an additional reference signal allocated within a null subcarrier region of the SSB, The additional reference signal is scrambled by the beam index of the SSB, and The indication is dependent on the additional reference signal.

14. The device according to claim 12, wherein: The one or more processors are further configured to encode, for each SSB, an additional reference signal allocated outside of the SSB, The additional reference signal is scrambled by the beam index of the SSB, and The indication is dependent on the additional reference signal.

15. The apparatus of claim 12, wherein the one or more processors are further configured to: A primary synchronization signal PSS and a secondary synchronization signal SSS are encoded for each SSB, and The PSS and the SSS of each SSB are scrambled using the block index of the SSB.

16. A computer-readable storage medium storing instructions executed by one or more processors of a user equipment (UE), wherein when the instructions are executed, the one or more processors configure the UE to: receiving, from a fifth generation NodeB, i.e., a gNB, synchronization signal blocks SSB superimposed in time and frequency, each SSB being associated with a different transmission beam from the gNB in ​​the spatial domain, the SSBs each containing a primary synchronization signal PSS, a secondary synchronization signal SSS, and a physical broadcast channel PBCH; If the PSS and the SSS of each SSB do not depend on a block index of the SSB, receiving an additional reference signal scrambled by a beam index of the SSB and using the additional reference signal to distinguish between the SSBs; Determining a strongest SSB based on measurements of the PBCH for each SSB; as well as and transmitting an indication of the strongest SSB to the gNB.

17. The computer-readable storage medium of claim 16, wherein: The additional reference signal is allocated in the empty subcarrier region of the SSB.

18. A method for a user equipment UE, the method comprising: Decoding the time and frequency superimposed synchronization signal blocks SSB from the fifth generation NodeB, i.e. gNB, each SSB is associated with a different transmission beam from the gNB in ​​the spatial domain, and the SSBs each contain a physical broadcast channel PBCH; Determining a strongest SSB based on measurements of the PBCH for each SSB; encoding an indication of the strongest SSB for transmission to the gNB; For each SSB, decode the primary synchronization signal PSS and the secondary synchronization signal SSS, and For each SSB, a physical cell identifier ID and a cell timing are determined based on the PSS and the SSS, the PSS and the SSS of each SSB being scrambled using the same physical cell ID and not depending on a block index of the SSB.

19. The method according to claim 18, further comprising: For each SSB, decoding an additional reference signal allocated in a null subcarrier region of the SSB, the additional reference signal being scrambled by a beam index of the SSB, and The indication is determined based on the additional reference signal.

20. The method of claim 19, wherein: The additional reference signal is included in a plurality of the empty subcarrier regions of each SSB.

21. The method of claim 19, wherein: The additional reference signal in each SSB is frequency domain multiplexed within the empty subcarrier region.

22. The method of claim 19, wherein: The additional reference signal is set at a different frequency in each SSB.

23. The method of claim 18, further comprising: For each SSB, an additional reference signal allocated outside the SSB is decoded, the additional reference signal being scrambled by a beam index of the SSB, and the indication is determined based on the additional reference signal.

24. A method for a user equipment UE, the method comprising: Decoding the time and frequency superimposed synchronization signal blocks SSB from the fifth generation NodeB, i.e. gNB, each SSB is associated with a different transmission beam from the gNB in ​​the spatial domain, and the SSBs each contain a physical broadcast channel PBCH; Determining a strongest SSB based on measurements of the PBCH for each SSB; For each SSB, decode the primary synchronization signal PSS and the secondary synchronization signal SSS, For each SSB, a physical cell identifier ID and a cell timing are determined based on the PSS and the SSS, and the PSS and the SSS of each SSB are scrambled using a block index of the SSB, wherein the SSB block index associated with the SSB is mapped to the same orthogonal frequency division multiplexing OFDM symbol index and time slot index within a downlink frame.

25. The method according to claim 24, further comprising: splitting the measurement of the PBCH of the SSB into measurements of the PBCH of each SSB, and Repeat the following steps over multiple iterations: identifying a block index associated with a demodulation reference signal DMRS of the PBCH having the highest reference signal received power L1-RSRP level measurement, After identifying the PBCH with the highest L1-RSRP level measurement, decoding the PBCH with the highest L1-RSRP level measurement, reconstructing the PBCH with the highest L1-RSRP level measurement, and The reconstructed PBCH is subtracted from the SSB.

26. The method according to claim 25, further comprising: When the cyclic redundancy check CRC of the decoded PBCH fails, the iteration is terminated early.

27. The method of claim 25, further comprising: The number of superimposed SSBs is determined by higher layer signaling from the gNB.

28. The method according to claim 27, further comprising: The maximum number of iterations is limited to the number of superimposed SSBs based on the higher layer signaling.

29. A method for a base station, the method comprising: A synchronization signal block SSB with encoding time and frequency superposition, each SSB is associated with a different transmission beam in the spatial domain, and each of the SSBs contains a physical broadcast channel PBCH; encoding the number of superimposed SSBs by higher layer signaling for transmission to a user equipment UE; decoding, from the UE, an indication of a strongest SSB received by the UE; as well as A primary synchronization signal PSS and a secondary synchronization signal SSS are encoded for each SSB, wherein the PSS and the SSS of each SSB are scrambled using the same physical cell ID and are independent of a block index of the SSB.

30. The method of claim 29, further comprising: An additional reference signal allocated in a null subcarrier region of the SSB is encoded for each SSB, the additional reference signal is scrambled by a beam index of the SSB, and the indication depends on the additional reference signal.

31. The method of claim 29, further comprising: An additional reference signal allocated outside the SSB is encoded for each SSB, the additional reference signal is scrambled by a beam index of the SSB, and the indication depends on the additional reference signal.

32. The method of claim 29, further comprising: A primary synchronization signal PSS and a secondary synchronization signal SSS are encoded for each SSB, and the PSS and the SSS of each SSB are scrambled using a block index of the SSB.

33. A computer program product comprising a computer program which, when executed by a processor, causes the processor to perform the method of any one of claims 18 to 32.

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