A joint beam management synchronization and l1 measurement procedure for new radio systems

Abstract

A method to jointly perform beam management, synchronization, and L1 measurements using a single synchronization signal block (SSB) burst in NR systems is proposed to improve data rate and to reduce power consumption. In a scheduling based SSB method, a UE is scheduled to perform either beam management or synchronization and L1 measurements alternatively. In a joint SSB method, a UE performs beam management, synchronization, and L1 RSRP / SNR measurements within a single SSB burst simultaneously. The UE can dynamically switch between the two SSB methods based on predefined conditions. Further, multiple joint SSB modes are introduced for the joint SSB method, where either

Description

[Technical Field]

[0001] The disclosed embodiments generally relate to wireless communication, and more specifically to a procedure for beam management, synchronization and L1 measurement in a 5G New Radio (NR) cellular communication network. [Previous Technology]

[0002] Over the years, wireless communication networks have grown exponentially. Long Term Evolution (LTE) systems offer high peak data rates, low latency, improved system capacity, and low operating costs due to a simplified network architecture. LTE systems, also known as 4G systems, also provide seamless integration with legacy wireless networks such as GSM, CDMA, and Universal Mobile Telecommunications System (UMTS). In LTE systems, the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) comprises multiple evolved Node-Bs (eNodeBs or eNBs) that communicate with multiple mobile stations (called User Equipment (UEs)). 3GPP networks typically consist of a hybrid of 2G / 3G / 4G systems. The Next Generation Mobile Network (NGMN) Committee has decided to focus future NGMN activities on defining the end-to-end requirements for 5G New Radio (NR) systems. In 5G NR, base stations are also called gNodeBs or gNBs.

[0003] The frequency bands of 5G NR are divided into two distinct frequency ranges. Frequency range 1 (FR1) includes bands below 6 GHz, some of which are traditionally used in previous standards but have been expanded to cover potential new spectrum offerings from 410 MHz to 7125 MHz. Frequency range 2 (FR2) includes bands from 24.25 GHz to 71.0 GHz. Within this millimeter-wave (mmWave) range, the bands in FR2 have shorter propagation ranges than those in FR1, but offer higher available bandwidth. To compensate for the high propagation loss in 5G mmWave systems, UEs are typically equipped with multiple antennas for beamforming. For downlink data reception, the UE requires beam management (BM), synchronization (time and frequency), and accurate Layer 1 (L1) measurements of the reference signal.

[0004] Similar to LTE, in 5G NR, the primary synchronization signal (PSS) and secondary synchronization signal (SSS) represent the Physical Cell Identifier (PCI), and the Physical Broadcast Channel (PBCH) carries the master information block (MIB). The SS block (SSB) in 5G NR represents the synchronization signal block, referencing the synchronization signal (PSS / SSS) and PBCH blocks, as the synchronization signal and PBCH channel are packaged into a single block. SSBs are transmitted periodically, with each SSB burst containing both the PSS / SSS and PBCH. In traditional designs, beam management, synchronization, and L1 RSRP / SNR measurements operate on different SSBs. A design that jointly performs beam management, synchronization, and L1 RSRP / SNR measurements will significantly benefit the UE in terms of data rate and power consumption. [Summary of the Invention]

[0005] A method is proposed to jointly perform beam management, synchronization, and L1 measurements in an NR system using a single Synchronization Signal Block (SSB) burst to improve data rate and reduce power consumption. In the scheduling-based SSB method, the UE is scheduled to alternately perform beam management or synchronization and L1 measurements. In the joint SSB method, the UE performs beam management, synchronization, and L1 RSRP / SNR measurements simultaneously in a single SSB burst. The UE can dynamically switch between the two SSB methods based on predetermined conditions. Furthermore, multiple joint SSB modes are introduced for the joint SSB method, using 3 or 4 OFDM symbols per SSB burst. The UE can dynamically switch between joint SSB modes based on the pilot contamination level on the OFDM symbols carrying the PSS.

[0006] In one embodiment, the UE monitors synchronization signal block (SSB) transmissions in a mobile communication network, wherein the SSB transmissions include SSB bursts periodically transmitted from the network to the UE. The UE receives a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH) within a single SSB burst. The UE performs operations using a joint SSB method for beam management and simultaneously performs at least one of synchronization and L1 measurements using the received PSS, SSS, and PBCH within a single SSB burst. In one example, the UE determines predetermined conditions for dynamically switching between the joint SSB method and a scheduling-based SSB method. In another example, the UE determines a pilot contamination level for dynamically switching between different joint SSB modes under the joint SSB method.

[0007] Other embodiments and advantages are described in the following detailed description. This overview is not intended to define the invention. The invention is defined by the claims.

Implementation Method

[0009] Reference will now be made in detail to some embodiments of the present invention, examples of which are shown in the accompanying drawings.

[0010] Figure 1 illustrates an exemplary 5G New Radio (NR) network 100 according to the present invention, comprising UEs supporting beam management, synchronization, and L1 measurement using the same Synchronization Signal Block (SSB). The 5G NR network 100 includes a User Equipment (UE) 101 and multiple base stations, including a serving base station gNB 102. UE 101 is communicatively connected to the serving gNB 102, which provides radio access (e.g., 5G NR technology) using Radio Access Technology (RAT). UE 101 may be a smartphone, wearable device, Internet of Things (IoT) device, tablet, etc. Optionally, UE 101 may be a laptop (NB) or personal computer (PC) with a data card inserted or installed, including a modem and RF transceiver, to provide wireless communication capabilities. To compensate for the high propagation loss in 5G millimeter-wave systems, UEs are typically equipped with multiple antennas to achieve beamforming. For downlink (DL) data reception, the UE requires accurate L1 measurements of beam management (BM), synchronization (time and frequency), and reference signals.

[0011] Similar to LTE, in 5G NR, the Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) represent the Physical Cell Identifier (PCI), and the Physical Broadcast Channel (PBCH) carries the Master Information Block (MIB). The SS Block (SSB) in 5G NR represents the Synchronization Signal Block, which refers to both the Synchronization Signal (PSS / SSS) and PBCH blocks, as the Synchronization Signal and PBCH channels are packaged into a single block. SSBs are transmitted periodically, with each SSB burst containing both the PSS / SSS and PBCH. In traditional designs, beam management, synchronization, and RSRP / SNR measurements operate on different SSBs; this is known as schedule-based SSB operation. A design that jointly performs beam management, synchronization, and RSRP / SNR measurements will significantly benefit the UE in terms of data rate and power consumption.

[0012] According to a novel aspect, a method is proposed for simultaneously performing beam management, synchronization, and RSRP / SNR measurements using a single SSB burst in an NR system to improve data rate and reduce power consumption. This novel method is also known as joint SSB operation. As shown in Figure 1, a single SSB burst [i] is typically used for beam management (BM), while the next single SSB burst [i+1] is typically used for synchronization and L1 measurements. In a novel aspect, under joint SSB operation, a single SSB burst [i+n] is used simultaneously for BM, synchronization, and L1-RSRP measurements. Joint SSB operation can be performed in different joint SSB modes. Depending on different conditions, the UE can dynamically switch to different joint SSB modes for joint SSB operation, or the UE can dynamically switch between joint SSB operation and scheduling-based SSB operation to adapt to service conditions.

[0013] Figure 2 shows a simplified block diagram of a wireless device, such as a UE 201 and gNB 211 according to an embodiment of the present invention in a 5G NR network 200. gNB 211 has an antenna 215 that transmits and receives radio signals, and an RF transceiver module 214 coupled to the antenna 215 that receives RF signals from the antenna 215, converts them into baseband signals, and sends them to a processor 213. The RF transceiver 214 also converts baseband signals received from the processor 213 into RF signals and sends them to the antenna 215. The processor 213 processes the received baseband signals (e.g., the one containing a SCell / PSCell append / add command) and calls different functional modules to execute features in gNB 211. A memory 212 stores program instructions and data 220 to control the operation of gNB 211. In the example of Figure 2, gNB 211 also includes a protocol stack 280 and a set of control function modules and circuitry 290. Protocol stack 280 may include a Non-Access Stratum (NAS) layer for communicating with the AMF / SMF / connecting to the core network MME entity, a Radio Resource Control (RRC) layer for higher-layer configuration and control, a Packet Data Convergence Protocol / Radio Link Control (PDCP / RRC) layer, a Media Access Control (MAC) layer, and a Physical (PHY) layer. In one example, control function modules and circuits 290 include configuration / control circuitry 291 for configuring measurement reports and active sets for the UE, handover processing circuitry for sending cell handover to the UE upon handover decision, and a scheduling circuitry 292 for controlling the process.

[0014] Similarly, UE 201 has a memory 202, a processor 203, and an RF transceiver module 204. The RF transceiver module 204 is coupled to an antenna 205, receives RF signals from the antenna 205, converts them into baseband signals, and sends them to the processor 203. The RF transceiver 204 also converts the received baseband signals from the processor 203 into RF signals and sends them to the antenna 205. The processor 203 processes the received baseband signals, calling different functional modules and circuits to execute features in UE 201. The memory 202 stores data and program instructions 210 to be executed by the processor 203 to control the operation of UE 201. Suitable processors include, for example, dedicated processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application-specific integrated circuits (ASICs), file program gate arrays (FPGAs), and other types of integrated circuits (ICs) and / or state machines. The software-associated processor can be used to implement and configure features of UE 201.

[0015] UE 201 also includes a protocol stack 260 and a set of control function modules and circuits 270. Protocol stack 260 may include a NAS layer for communicating with AMF / SMF / MME entities connected to the core network, an RRC layer for higher-level configuration and control, a PDCP / RLC layer, a MAC layer, and a PHY layer. Control function modules and circuits 270 may be implemented and configured via software, firmware, hardware, and / or combinations thereof. Control function modules and circuits 270 cooperate with each other when executed by processor 203 via program instructions contained in storage 202 to allow UE 201 to perform implementations and functional tasks and features within the network. In one example, control function modules and circuits 270 include configuration / control circuitry 271 for acquiring measurement and configuration information and controlling corresponding operations, beam management circuitry 272 for performing DL and UL beam management, and synchronization and measurement processing circuitry 273 for performing synchronization and L1 RSPR / RSRQ / SNR measurement functions based on configuration received from the network.

[0016] Figure 3 illustrates periodic SSB transmission and joint beam management, synchronization, and L1 measurements using the same SSB burst. During cell search operations performed when the UE powers on, mobility in connected mode, idle mode mobility (e.g., cell reselection or handover), and inter-RAT mobility to the NR system, the UE decodes the NR synchronization signal and physical broadcast channel (PBCH) to derive the necessary information for accessing the cell. The synchronization signal / PBCH block (SSB) consists of the PSS, SSS, and PBCH. The UE can also use the synchronization signal for RSRP / RSRQ and SNR L1 measurements. Furthermore, a beam management (BM) procedure is used in 5G NR to acquire and maintain a set of beams to ensure gNB and UE beam alignment for data communication. To enable beam scanning of the PSS / SSS and PBCH, SS burst sets are defined. An SS burst set consists of a set of SSBs, each of which may be transmitted on a different beam. The network notifies the UE which SSBs are being transmitted.

[0017] In the example in Figure 3, SSB bursts are transmitted periodically (e.g., 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms), depending on the different parameter sets. During initial cell search or idle mode movement, the UE may assume a default period of 20 milliseconds. Typically, a single SSB burst[i] is used for BM or for synchronization and L1 RSRP / RSRQ measurements, alternately scheduled. In a novel aspect, OFDM symbols in a single SSB burst are jointly used for BM, synchronization, and L1 RSRP / RSRQ measurements. BM, synchronization, and L1 RSRP / RSRQ measurements are performed simultaneously in the same SSB burst[i], SSB burst[i+1], SSB burst[i+2], SSB burst[i+3], etc. Such UE operation is also referred to as the joint SSB method, while the conventional UE operation is referred to as the scheduling-based SSB method.

[0018] Figure 4 illustrates different examples of joint beam management, synchronization, and L1 measurements using the same SSB burst according to an embodiment of the present invention. As shown in Figure 4, in each SSB burst, the synchronization signals PSS, SSS, and PBCH always appear together in consecutive OFDM symbols. Each SSB burst occupies 4 OFDM symbols in the time domain and is distributed across 240 subcarriers (20 RBs) in the frequency domain. PSS occupies the first OFDM symbol and spans 127 subcarriers. SSS is located in the third OFDM symbol and spans 127 subcarriers. There are 8 unused subcarriers below SSS and 9 unused subcarriers above SSS. PBCH occupies two full OFDM symbols (PBCH0 and PBCH2) and spans 240 subcarriers, with the third OFDM symbol spanning 48 subcarriers below and above SSS.

[0019] The three different working examples can be considered as different joint SSB modes for joint BM, synchronization, and L1 measurement operations. In the first example 1, the PBCH0 and PBCH2 symbols are used for synchronization and L1 measurement, the PBCH0 and SSS symbols are used for beam management (BM), and PSS is not used. In the second example 2, the PBCH0 and PBCH2 symbols are used for synchronization and L1 measurement, and the PSS, PBCH0, and SSS symbols are used for beam management. In example 3, the PSS and SSS symbols are used for synchronization and L1 measurement, and the PBCH0, SSS, and PBCH2 symbols are used for beam management. Depending on the different UE configurations and real-time traffic conditions, the UE can dynamically apply different joint SSB modes accordingly.

[0020] Figure 5 illustrates a first embodiment of different SSB methods for performing beam management, synchronization, and L1 measurements using predetermined conditions. In the embodiment of Figure 5, two different SSB methods are used: SSB method 1 is a schedule-based SSB method in which the UE performs beam management, synchronization, and L1 measurements using different SSB bursts; SSB method 2 is a joint SSB method in which a single SSB burst is simultaneously used in conjunction for BM, synchronization, and L1 RSRP / RSRQ measurements.

[0021] In a novel aspect, a state machine is proposed to switch between two methods: SSB Method-1 (a scheduling-based SSB method) and SSB Method-2 (a joint SSB method). Two conditions are predetermined for the switching between the two SSB methods. Condition-1 is defined as: (DRX period < TH-1) && (SNR > TH-2) && (UE condition-1 is based on DL data throughput and BLER); Condition-2 is defined as (DRX period ≥ TH-3) || (SNR ≤ TH-4) || (UE condition-2 depends on DL data throughput and BLER). If Condition-1 is satisfied, the UE switches from SSB Method-1 to SSB Method-2; if Condition-2 is satisfied, the UE switches from SSB Method-2 to SSB Method-1. Note that in the state machine, SSB Method-1 may represent a high-performance mode, while SSB Method-2 may represent a power-saving mode. For SSB method-2, it prefers a short DRX period, a high SNR, a low data rate required by the UE, and no restrictions on BLER (these requirements are essentially the same as condition-1). For SSB method-1, it can tolerate a long DRX period, a low SNR, provide a high data rate, and provide a lower BLER (these benefits are essentially the same as condition-2).

[0022] Figure 6 illustrates a second embodiment of different joint SSB modes for performing joint beam management, synchronization, and L1 measurements using predetermined conditions. In the embodiment of Figure 6, three different joint SSB modes are defined under the joint SSB method. In joint SSB mode 1, the PBCH0 and PBCH2 symbols are used for synchronization and L1 measurements, the PBCH0 and SSS symbols are used for beam management, and the PSS is not used. In joint SSB mode 2, the PBCH0 and PBCH2 symbols are used for synchronization and L1 measurements, and the PSS, PBCH0, and SSS symbols are used for beam management. In joint SSB mode 3, the PSS and SSS symbols are used for synchronization and L1 measurements, and the PBCH0, SSS, and PBCH2 symbols are used for beam management. Note that joint SSB mode 1 uses only three OFDM symbols and does not use the PSS OFDM symbol; while joint SSB modes 2 and 3 use all four OFDM symbols.

[0023] In a novel aspect, in step 611, the UE determines the pilot contamination level on the PSS and then decides which joint SSB mode to operate (step 612). If the pilot contamination level on the PSS is higher than a threshold, it is preferable not to use the PSS symbol. As a result, the UE proceeds to step 613 and adopts joint SSB mode 1, for example, PBCH0 and PBCH2 symbols are used for synchronization and L1 measurements, PBCH0 and SSS symbols are used for beam management, and the PSS is not used. On the other hand, if the pilot contamination level on the PSS is lower than a threshold, the UE proceeds to step 614 and adopts joint SSB mode 2 or joint SSB mode 3, for example, all four OFDM symbols are used for BM, synchronization, and L1 measurements. In one example, PSS contamination can be determined by comparing the cell_ID_2 between the serving cell and neighboring cells (the same cell_ID_2 will generate the same PSS). If the same cell_ID_2 is found in one of the serving cell and neighboring cells, pilot contamination on the PSS is detected.

[0024] Figure 7 is a flowchart of a method for joint beam management, synchronization, and L1 measurement according to a novel aspect. In step 701, the UE monitors the transmission of Synchronization Signal Blocks (SSBs) in the mobile communication network, wherein the SSB transmission includes SSB bursts periodically transmitted from the network to the UE. In step 702, the UE receives a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH) within a single SSB burst. In step 703, the UE performs operations using the joint SSB method and performs at least one of beam management, synchronization, and L1 measurement using the received PSS, SSS, and PBCH within a single SSB burst. In one example, the UE determines predetermined conditions for dynamically switching between the joint SSB method and a scheduling-based SSB method. In another example, the UE determines a pilot contamination level for dynamically switching between different joint SSB modes under the joint SSB method.

[0025] Although the invention has been described in conjunction with certain specific embodiments for illustrative purposes, the invention is not limited thereto. Therefore, various modifications, adaptations, and combinations of the various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims. [Simplified Explanation of the Diagram]

[0008] Similar numbers in the accompanying drawings denote similar components, illustrating embodiments of the invention. Figure 1 illustrates an exemplary 5G New Radio (NR) network with a UE performing joint beam management, synchronization, and L1 measurements using individual synchronization signal block (SSB) bursts according to an aspect of the invention. Figure 2 shows a simplified block diagram of a wireless device according to an embodiment of the invention, such as a UE and a gNB. Figure 3 illustrates periodic SSB transmissions and joint beam management, synchronization, and L1 measurements using the same SSB burst. Figure 4 illustrates different examples of joint beam management, synchronization, and L1 measurements using the same SSB burst according to an embodiment of the invention. Figure 5 illustrates a first embodiment of different scheduling-based or joint-based SSB methods for performing beam management, synchronization, and L1 measurements using predetermined conditions. Figure 6 illustrates a second embodiment of different joint SSB modes for performing joint beam management, synchronization, and L1 measurements using predetermined conditions. Figure 7 is a flowchart of a method for joint beam management, synchronization, and L1 measurements according to a novel aspect.

Claims

1. A wireless communication method, comprising: Monitor the transmission of Synchronization Signal Block (SSB) of User Equipment (UE) in a mobile communication network, wherein the SSB transmission includes SSB bursts periodically transmitted from the network to the UE; receive the Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Physical Broadcast Channel (PBCH) in a single SSB burst; And to perform operations using the joint SSB method, for performing beam management and at least one of synchronization and L1 measurements using PSS, SSS and PBCH received in a single SSB burst.

2. The wireless communication method as described in claim 1, wherein, The PSS, SSS, and PBCH are allocated in the time domain to consecutive OFDM symbols within each SSB burst.

3. The wireless communication method as described in claim 1, wherein, The UE determines predetermined conditions for dynamically switching between the joint SSB method and the scheduling-based SSB method.

4. The wireless communication method as described in claim 3, wherein, When the first condition is met, the UE switches from the scheduling-based SSB method to the joint SSB method.

5. The wireless communication method as described in claim 3, wherein, When the second condition is met, the UE switches from the joint SSB method to the scheduling-based SSB method.

6. The wireless communication method as described in claim 3, wherein, The predetermined conditions include at least one of the following: discontinuous reception (DRX) period length, signal-to-noise ratio (SNR) value, downlink traffic, and block error rate (BLER) value.

7. The wireless communication method as described in claim 1, wherein, The UE determines the pilot pollution level on the PSS so that the UE can dynamically switch between different joint SSB modes under the joint SSB method.

8. The wireless communication method as described in claim 7, wherein, When the pilot pollution level on the PSS is higher than the threshold, the UE operates using the first joint SSB mode.

9. The wireless communication method as described in claim 7, wherein, When the pilot pollution level on the PSS is below the threshold, the UE operates using the second joint SSB mode.

10. The wireless communication method as claimed in claim 7, wherein the UE does not use PSS in a first joint SSB mode, and wherein the UE uses PSS in a second joint SSB mode.

11. A user equipment (UE), comprising: The transceiver monitors the transmission of synchronization signal blocks (SSBs) in the mobile communication network, where SSB transmissions include SSB bursts periodically sent from the network to the UE. The decoder decodes the primary synchronization signal (PSS), secondary synchronization signal (SSS), and physical broadcast channel (PBCH) within a single SSB burst; The controller performs operations using the joint SSB method to use the received PSS, SSS, and PBCH in a single SSB burst for at least one of beam management, synchronization, and L1 measurements.

12. The wireless communication UE as described in claim 11, wherein, PSS, SSS, and PBCH are allocated in the time domain to consecutive OFDM symbols within each SSB burst.

13. The wireless communication UE as described in claim 11, wherein, The UE determines predetermined conditions for dynamically switching between the joint SSB method and the scheduling-based SSB method.

14. The wireless communication UE as described in claim 13, wherein, When the first condition is met, the UE switches from the scheduling-based SSB method to the joint SSB method.

15. The wireless communication UE as described in claim 13, wherein, When the second condition is met, the UE switches from the joint SSB method to the scheduling-based SSB method.

16. The wireless communication UE as described in claim 13, wherein, The predetermined conditions include at least one of the following: discontinuous reception (DRX) period length, signal-to-noise ratio (SNR) value, downlink traffic, and block error rate (BLER) value.

17. The wireless communication UE as described in claim 11, wherein, The UE determines the pilot pollution level on the PSS to dynamically switch between different joint SSB modes under the joint SSB approach.

18. The wireless communication UE as described in claim 17, wherein, When the pilot pollution level on the PSS is higher than the threshold, the UE operates using the first joint SSB mode.

19. The wireless communication UE as described in claim 17, wherein, When the pilot pollution level on the PSS is below a threshold, the UE operates using the second joint SSB mode.

20. The wireless communication UE as claimed in claim 17, wherein the UE does not use PSS in a first joint SSB mode, and wherein the UE uses PSS in a second joint SSB mode.

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