Device and method for effectively utilizing physical random access channel resources and performing beam recognition through a physical random access channel

Abstract

A user equipment including a wireless transceiver and a controller is provided. The wireless transceiver performs wireless reception from and wireless transmission to a cellular station; the controller uses one or more first preambles in a PRACH time-frequency resource to perform a synchronous transmission to the cellular station on the PRACH via the wireless transceiver, or uses one or more second preambles in the PRACH time-frequency resource to perform an asynchronous or synchronous transmission to the cellular station on the PRACH via the wireless transceiver.

Description

[0001] Cross-reference

[0002] This application claims the priority of U.S. Provisional Application No. 62 / 475,966, filed on March 24, 2017, the entire content of which is incorporated herein by reference. Moreover, this application claims the priority of U.S. Provisional Application No. 62 / 475,970, filed on March 24, 2017, the entire content of which is incorporated herein by reference. Technical Field

[0003] The present invention generally relates to the design of a Physical Random Access Channel (PRACH), and particularly to methods and apparatuses for identifying beams through the PRACH and effectively utilizing PRACH resources. Background Art

[0004] The fifth-generation (5G) New Radio (NR) technology is an improvement over the fourth-generation (4G) Long Term Evolution (LTE). It provides extremely high speeds and capacities for wireless broadband communication by using higher unlicensed frequency bands (e.g., above 30 GHz, roughly referred to as millimeter wave (mmWave)). Due to the significant path loss and penetration loss at millimeter wavelengths, a technology called "beamforming" is adopted, and it plays an important role in establishing and maintaining a robust communication link.

[0005] Beamforming generally requires one or more antenna arrays, each of which includes multiple antennas. By appropriately setting the antenna weights that define the contribution of each antenna to the transmission or reception operation, the sensitivity of transmission / reception can be shaped to a particularly high value in a specific beamforming direction. By applying different antenna weights, different beam patterns can be achieved. For example, different directional beams can be sequentially adopted.

[0006] During a transmission (Tx) operation, beamforming can direct the signal to the receiver of interest. Similarly, during a reception (Rx) operation, beamforming can provide high sensitivity when receiving signals from the transmitter of interest. Since the transmission power can be non-uniformly focused, for example, focused at a fixed angle of interest, compared with the traditional practice of not using beamforming and relying on almost isotropic transmission, beamforming can provide a better link budget because it requires lower transmission (Tx) power and higher received signal power.

[0007] However, the above technologies face certain challenges. For example, in multi-beam operation, the movement of a user equipment (UE), the angular rotation of the UE, or terrain that blocks the line-of-light may cause a degradation in the signal quality of the active beam. In some cases, the signal quality may degrade rapidly, and there may not be enough time to switch beams, so beam failure may occur. Therefore, a mechanism for recovering from beam failure is desired.

[0008] In addition, in 5G NR technology, there is a situation where the Physical Random Access Channel (PRACH) preamble can be used for an uplink request when a Timing Advance (TA) command and a Cell Radio Network Temporary Identifier (C-RNTI) are not required to respond to an uplink request. Therefore, the PRACH design needs to be improved to more effectively utilize PRACH resources to adapt to this situation. Summary of the Invention

[0009] To solve the above problems, this application proposes to recover from beam failure through the PRACH. Specifically, downlink reference signals (such as Channel State Information-Reference Signal (CSI-RS) resources, Synchronization Signal (SS) blocks, or Physical Broadcast Channel (PBCH) blocks) and PRACH resources (such as PRACH preambles, RACH opportunities, or a combination of the above) are provided for beam identification to recover from beam failure or to facilitate handover from one cell to another. Additionally, this application proposes a more flexible PRACH design for improving the utilization efficiency of PRACH resources. Specifically, different preambles can be flexibly segmented for asynchronous and synchronous transmissions within the PRACH time-frequency resources, and / or the bandwidth and / or cyclic shift for synchronous transmission can be reduced to less than those for asynchronous transmission.

[0010] In a first aspect of the present application, a user equipment (UE) including a wireless transceiver and a controller is provided. The wireless transceiver is configured to perform wireless transmission to and wireless reception from a cellular station. The controller is configured to use one or more first preambles in PRACH time-frequency resources on a PRACH channel to perform synchronous transmission to the cellular station on the PRACH channel via the wireless transceiver, or use one or more second preambles in the PRACH time-frequency resources on the PRACH channel to perform asynchronous transmission or synchronous transmission to the cellular station on the PRACH via the wireless transceiver.

[0011] In a second aspect of the present application, a method for effectively utilizing a PRACH is provided, which is executed by a UE wirelessly connected to a cellular station. The method for effectively utilizing a PRACH includes the steps of: using one or more first preambles in PRACH time-frequency resources on a PRACH channel to perform synchronous transmission to the cellular station on the PRACH channel; or using one or more second preambles in PRACH time-frequency resources on the PRACH channel to perform asynchronous transmission or synchronous transmission to the cellular station on the PRACH.

[0012] In a third aspect of the present application, a cellular station including a wireless transceiver and a controller is provided. The wireless transceiver is configured to perform wireless transmission to and wireless reception from the cellular station. The controller is used to configure one or more first preambles within the PRACH time-frequency resources for the UE on the PRACH to perform synchronous reception of transmissions from the UE on the PRACH via the wireless transceiver, and configure one or more second preambles within the PRACH time-frequency resources on the PRACH to perform reception of asynchronous transmission or synchronous transmission on the PRACH, and transmit the configuration of the first preamble and the second preamble within the PRACH time-frequency resources to the UE via the wireless transceiver.

[0013] In a fourth aspect of the present application, a method for effectively utilizing a PRACH is provided, which is executed by a cellular station wirelessly connected to a UE. The method for effectively utilizing a PRACH includes the steps of: configuring one or more first preambles within the PRACH time-frequency resources for the UE on the PRACH to perform synchronous reception of transmissions from the UE on the PRACH, and configuring one or more second preambles within the PRACH time-frequency resources for the UE on the PRACH to perform reception of asynchronous transmission or synchronous transmission from the UE on the PRACH; and transmitting the configuration of the first preamble and the second preamble within the PRACH time-frequency resources to the UE.

[0014] Other aspects and features of the present invention will become apparent to those skilled in the art upon reading the following description of specific embodiments of a UE, a cellular station, and methods for identifying a beam through a PRACH and for efficiently utilizing PRACH resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present application can be more fully understood by reference to the following detailed description and examples read in conjunction with the accompanying drawings, in which:

[0016] Figure 1 is a block diagram of a wireless communication environment according to an embodiment of the present application;

[0017] Figure 2 is a block diagram of a UE 110 shown according to an embodiment of the present application;

[0018] Figure 3 is a block diagram of a cellular station shown according to an embodiment of the present application;

[0019] Figure 4 is a schematic diagram showing the association between CSI-RS resources, SS / PBCH blocks, and multiple sets of PRACH preambles and PRACH opportunities according to an embodiment of the present application;

[0020] Figure 5 is a schematic diagram showing the association between CSI-RS resources, and multiple sets of PRACH preambles and RACH opportunities according to an embodiment of the present application;

[0021] Figure 6 is a schematic diagram showing the association between CSI-RS resources, multiple sets of PRACH preambles and RACH opportunities according to another embodiment of the present application;

[0022] Figure 7 is a schematic diagram showing the association between CSI-RS resources, multiple sets of PRACH preambles and RACH opportunities according to yet another embodiment of the present application;

[0023] Figure 8 is a schematic diagram showing the association between CSI-RS resources, multiple sets of PRACH preambles and RACH opportunities according to an embodiment of the present application;

[0024] Figure 9 is a schematic diagram showing a joint PRACH design for beam failure recovery, and other uplink requests or indications according to an embodiment of the present application;

[0025] Figure 10 is a schematic diagram showing the utilization of PRACH resources for asynchronous and synchronous transmissions according to an embodiment of the present application;

[0026] Figure 11 A schematic diagram of a PRACH preamble bandwidth for asynchronous and synchronous transmissions, shown according to an embodiment of the present application; and

[0027] Figure 12 A schematic diagram of PRACH resource utilization for asynchronous and synchronous transmissions, shown according to another embodiment of the present application. Detailed implementation manners

[0028] The following description is made for the purpose of illustrating the general principles of the present application and should not be construed in a limiting sense. It should be understood that these embodiments can be implemented using software, hardware, firmware, or any combination thereof. As used herein, the terms "comprising" and / or "including" specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0029] Figure 1 A block diagram of a wireless communication environment according to an embodiment of the present application. The wireless communication environment 100 includes a user equipment (UE) 110 and a 5G NR network 120, where the UE 110 can initiate a random access procedure for beam failure recovery, beam switching, or uplink requests, and can be wirelessly connected to the 5G NR network 120 to obtain mobile services.

[0030] The UE 110 can be a feature phone, a smart phone, a tablet personal computer (PC), a laptop computer, or any wireless communication device that supports the cellular technology (i.e., 5G NR technology) used by the 5G NR network 120. In particular, the wireless communication device employs beamforming technology for wireless transmission and / or reception.

[0031] The 5G NR network 120 includes a Radio Access Network (RAN) 121 and a Next Generation Core Network (NG-CN) 122.

[0032] The RAN 121 is responsible for processing radio signals, terminating radio protocols, and connecting the UE 110 to the NG-CN 122. Additionally, the RAN 121 is responsible for periodically broadcasting minimum system information SI and providing another SI either through periodic broadcast or upon request from the UE 110. The RAN 121 may include one or more cellular stations (e.g., gNBs) that support high frequency bands (e.g., above 24 GHz), and each gNB may further include one or more Transmission Reception Points (TRPs), where each gNB or TRP may be referred to as a 5G cellular station. Some gNB functions may be distributed among different TRPs, while others may be centralized, enabling the flexibility and scope of a particular deployment to meet the requirements of a specific scenario.

[0033] The NG-CN 122 typically consists of various network functions, including the Access and Mobility Function (AMF), Session Management Function (SMF), Policy Control Function (PCF), Application Function (AF), Authentication Server Function (AUSF), User Plane Function (UPF), and User Data Management (UDM), where each network function may be implemented as a network component on dedicated hardware, or as a software instance running on dedicated hardware, or as a virtualized function instantiated on a suitable platform (e.g., cloud infrastructure).

[0034] The AMF provides UE-based authentication, authorization, mobility management, etc. The SMF is responsible for session management and assigns Internet Protocol (IP) addresses to the UE. It also selects and controls the UPF for data transmission. If the UE has multiple sessions, different SMFs may be assigned to each session to manage them separately and may provide different functions in each session. The AF provides information about packet flows to the PCF, which is responsible for policy control, to support Quality of Service (QoS). Based on this information, the PCF determines policies regarding mobility and session management to enable the normal operation of the AMF and SMF. The AUSF stores data for UE authentication, while the UDM stores the UE's subscription data.

[0035] It should be understood that Figure 1The 5G NR network 120 depicted is for illustrative purposes only and is not intended to limit the scope of this application. This application can also be applied to other cellular technologies, such as future enhanced technologies of 5G NR technology.

[0036] Figure 2 is a block diagram showing a UE 110 according to an embodiment of the present application. The UE 110 includes a wireless transceiver 10, a controller 20, a storage device 30, a display device 40, and an input / output (I / O) device 50.

[0037] The wireless transceiver 10 is configured to perform wireless transmission to and wireless reception from the RAN 121. Specifically, the wireless transceiver 10 includes a radio frequency (RF) device 11, a baseband processing device 12, and an antenna 13, where the antenna 13 may include one or more antennas for beamforming. The baseband processing device 12 is configured to perform baseband signal processing and control the communication between a user identification card (not shown) and the RF device 11. The baseband processing device 12 may include multiple hardware components to perform baseband signal processing, including analog-to-digital conversion (ADC) / digital-to-analog conversion (DAC), gain adjustment, modulation / demodulation, encoding / decoding, etc. The RF device 11 may receive an RF wireless signal via the antenna 13, convert the received RF wireless signal into a baseband signal to be processed by the baseband processing device 12, or receive a baseband signal from the baseband processing device 12 and convert the received baseband signal into an RF wireless signal, and then transmit the RF wireless signal through the antenna 13 later. The RF device 11 may also include multiple hardware devices to perform radio frequency conversion. For example, the RF device 11 may include a mixer to multiply the baseband signal by a carrier oscillating at the radio frequency of the supported cellular technology, where the radio frequency may be any radio frequency used in 5G NR technology (e.g., for millimeter wave) or another radio frequency, depending on the cellular technology used.

[0038] The controller 20 can be a general-purpose processor, a micro control unit (MCU), an application processor, a digital signal processor (DSP), etc., which includes various circuits for providing data processing and computing functions, controlling the wireless transceiver 10 to perform wireless communication with the RAN 121, storing and retrieving data (such as program codes) to and from the storage device 30, transmitting a series of frame data (such as representing text messages, graphics, images, etc.) to the display device 40, and receiving signals from the I / O device 50. In particular, the controller 20 coordinates the foregoing operations of the wireless transceiver 10, the storage device 30, the display device 40, and the I / O device 50 for performing the method for beam recognition through the PRACH and the method for effectively utilizing the PRACH.

[0039] In another embodiment, the controller 20 can be incorporated into the baseband processing device 12 to serve as a baseband processor.

[0040] As those skilled in the art will recognize, the circuits of the controller 20 will generally include transistors, which are configured to control the operation of the circuits according to the functions and operations described herein. As will be further understood, the specific structure or interconnection of the transistors will typically be determined by a compiler (such as a register transfer language (RTL) compiler). The RTL compiler can operate on a script that is very similar to assembly language code and compile the script into a form for layout or fabricating the final circuit. In fact, the role and use of RTL in facilitating the electronic and digital system design process are well known.

[0041] The storage device 30 is a non-transitory machine-readable storage medium, including memories such as flash memory or non-volatile random access memory (NVRAM), or magnetic storage devices such as hard disks or magnetic tapes, or optical discs, or any combination thereof, to store instructions and / or program codes, communication protocols, and / or methods for beam recognition through the PRACH and applications for effectively utilizing the PRACH.

[0042] The display device 40 may be a liquid-crystal display (LCD), a light-emitting diode (LED) display, an electronic paper display (EPD), etc. for providing a display function. Alternatively, the display device 40 may further include one or more touch sensors disposed thereon or thereunder for detecting the touch, contact or proximity of an object, such as a finger or a stylus.

[0043] The I / O device 50 may include one or more buttons, a keyboard, a mouse, a touchpad, a camera, a microphone, and / or a speaker, etc. serving as a man-machine interface (MMI) for interacting with a user.

[0044] It should be understood that Figure 2 the components described in the embodiments of are only for illustrative purposes and are not intended to limit the scope of the present application. For example, the UE 110 may include more components, such as a power supply or a global positioning system (GPS) device. The power supply may be a mobile / replaceable battery that powers all other components of the UE 110, and the GPS device may provide the location information of the UE 110 for some location-based services or applications.

[0045] Figure 3 is a block diagram showing a cellular station according to an embodiment of the present application. The cellular station may be a 5G cellular station, such as a gNB or a TRP. The cellular station includes a wireless transceiver 60, a controller 70, a storage device 80, and a wired interface 90.

[0046] The wireless transceiver 60 is configured to perform wireless reception from the UE 110 and perform wireless transmission to the UE 110. Specifically, the wireless transceiver 60 includes an RF device 61, a baseband processing device 62, and an antenna 63, where the antenna 63 may include one or more antennas for beamforming. The functions of the RF device 61, the baseband processing device 62, and the antenna 63 are similar to those of the RF device 11, the baseband processing device 12, and the antenna 13 shown in the embodiments of Figure 2 so, for the sake of brevity, they will not be described herein again.

[0047] The controller 70 can be a general-purpose processor, MCU, application processor, DSP, etc., which includes various circuits for providing data processing and computing functions, controlling the wireless transceiver 60 for wireless communication with the UE 110, storing and retrieving data (such as program code) to and from the storage device 80, and transmitting messages to other network entities (such as other cellular stations in the RAN 121 or other network entities in the NG-CN 122) or receiving messages from other network entities through the wired interface 90. Specifically, the controller 70 coordinates the above operations of the wireless transceiver 60, the storage device 80, and the wired interface 90 to execute the method for beam recognition through the PRACH and the method for effectively utilizing the PRACH.

[0048] In another embodiment, the controller 70 can be incorporated into the baseband processing device 62 to serve as a baseband processor.

[0049] As those skilled in the art will recognize, the circuits of the controller 70 generally include transistors that are configured to control the operation of the circuits according to the functions and operations described herein. As will be further understood, the specific structure or interconnection of the transistors will typically be determined by a compiler (such as an RTL compiler). The RTL compiler can operate on a script that is very similar to assembly language code and compile the script into a form for layout or fabricating the final circuit. In fact, the role and use of RTL in facilitating the electronic and digital system design process are well known.

[0050] The storage device 80 can be a memory such as a flash memory or NVRAM, or a magnetic storage device such as a hard disk or magnetic tape, or an optical disc, or any combination thereof, for storing instructions and / or program code, communication protocols, and / or methods for applications for beam recognition through the PRACH and for effectively utilizing the PRACH.

[0051] The wired interface 90 is responsible for providing wired communication with other network entities (such as other cellular stations in the RAN 121 or other network entities in the NG-CN 122). The wired interface 90 can include a cable modem, an Asymmetric Digital Subscriber Line (ADSL) modem, a Fiber-Optic Modem (FOM), and / or an Ethernet interface.

[0052] It should be understood that Figure 3The components described in the embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. For example, the cellular station may further include other functional devices such as a display device (e.g., LCD, LED display, or EPD, etc.), I / O devices (e.g., buttons, keyboard, mouse, touchpad, camera, microphone, speaker, etc.), and / or a power supply, etc.

[0053] Note that in the present application, the association between the downlink reference signal and the PRACH preamble and RACH opportunity (e.g., time-frequency resource) is configured to indicate to the cellular station the downlink reference signal selected by the UE when the PRACH preamble is transmitted by the UE and detected by the cellular station. The RACH opportunity is defined as the time-frequency resource for transmitting PRACH message 1 using the configured PRACH preamble format, on which PRACH message 1 is transmitted using a single TX beam. In addition, using PRACH transmission includes identifying new candidate beams to recover from beam failure or facilitate handover from one cell to another. When beam failure occurs or a cell handover is triggered, the downlink reference signal associated with the candidate beam will be selected from a set of downlink reference signals associated with all beams, where the set of downlink reference signals includes CSI-RS resources, SS blocks, or PBCH blocks, or any combination thereof. Based on this association, the PRACH preamble and RACH opportunity corresponding to the newly selected downlink reference signal (i.e., CSI-RS resource or SS / PBCH block) of the candidate beam can be determined, and the UE can transmit a random access preamble according to the determined PRACH preamble for the gNB at the determined RACH opportunity. On the other hand, according to this association, when a random access preamble is received, the gNB knows that beam failure has occurred or a cell handover has been triggered, and knows which beam is the new candidate beam selected by the UE when the random access preamble is received.

[0054] Figure 4 is a schematic diagram showing the association between CSI-RS resources, SS / PBCH blocks and multiple sets of PRACH preambles and RACH opportunities according to an embodiment of the present application.

[0055] In this embodiment, the beam width of each CSI-RS resource is substantially the same as the beam width of each SS / PBCH block. Therefore, the association between the CSI-RS resource and the PRACH preamble and RACH opportunity can be the same as the association between the SS / PBCH block and the PRACH preamble and RACH opportunity. That is, this association associates one CSI-RS resource or SS / PBCH block with a set of PRACH preambles and RACH opportunities.

[0056] As Figure 4As shown, according to the association, the first SS / PBCH block and the first CSI-RS resource correspond to the first set of PRACH preambles and RACH opportunities, and thus the beam for the first SS / PBCH block and the first CSI-RS resource corresponds to the beam for the first set of PRACH preambles and RACH opportunities.

[0057] Similarly, according to the association, the second SS / PBCH block and the second CSI-RS resource correspond to the second set of PRACH preambles and RACH opportunities. Therefore, the beam for the second SS / PBCH block and the second CSI-RS resource corresponds to the beam for the second set of PRACH preambles and RACH opportunities. According to the association, the third SS / PBCH block and the third CSI-RS resource correspond to the third set of PRACH preambles and RACH opportunities. Therefore, the beam for the third SS / PBCH block and the third CSI-RS corresponds to the beam for the third set of PRACH preambles and RACH opportunities. According to the association, the fourth SS / PBCH block and the fourth CSI-RS resource correspond to the fourth set of PRACH preambles and RACH opportunities. Therefore, the beam for the fourth SS / PBCH block and the fourth CSI-RS resource corresponds to the beam for the fourth set of PRACH preambles and RACH opportunities.

[0058] Note that, in another embodiment, an association is configured between CSI-RS resources and PRACH preambles. For example, a first CSI-RS resource is associated with a first set of PRACH preambles, a second CSI-RS resource is associated with a second set of PRACH preambles, and so on. In another embodiment, an association is configured between SS / PBCH blocks and PRACH preambles. For example, a first SS / PBCH block is associated with a first set of PRACH preambles, a second SS / PBCH block is associated with a second set of PRACH preambles, and so on. In another embodiment, an association is configured between CSI-RS resources and RACH opportunities. For example, a first CSI-RS resource is associated with a first RACH opportunity, a second CSI-RS resource is associated with a second RACH opportunity, and so on. In another embodiment, an association is configured between SS / PBCH blocks and RACH opportunities. For example, a first SS / PBCH block is associated with a first RACH opportunity, a second SS / PBCH block is associated with a second RACH opportunity, and so on. In another embodiment, an association is configured between CSI-RS resources and both PRACH preambles and RACH opportunities. For example, a first CSI-RS resource is associated with a first set of PRACH preambles and a first RACH opportunity, a second CSI-RS resource is associated with a second set of PRACH preambles and a second RACH opportunity, and so on. In another embodiment, an association is configured between SS / PBCH blocks and both PRACH preambles and RACH opportunities. For example, a first SS / PBCH block is associated with a first set of PRACH preambles and a first RACH opportunity, a second SS / PBCH block is associated with a second set of PRACH preambles and a second RACH opportunity, and so on.

[0059] That is, for purposes of identifying new beams and handovers not limited to beam failure recovery, (1) an association is configured between CSI-RS resources and PRACH resources including preambles, opportunities (e.g., time-frequency resources), or a combination thereof; (2) an association is configured between SS / PBCH blocks and RACH resources including preambles, opportunities (e.g., time-frequency resources), or a combination thereof; (3) an association is configured between CSI-RS resources and SS / PBCH blocks and RACH resources including preambles, opportunities (e.g., time-frequency resources), or a combination thereof.

[0060] Figure 5 is a schematic diagram showing the association between CSI-RS resources and multiple sets of PRACH preambles and RACH opportunities according to an embodiment of the present application.

[0061] In this embodiment, the beamwidth of each CSI-RS resource is narrower than that of the downlink reference signal (e.g., SS / PBCH block), and the PRACH preamble and RACH opportunity are configured to be associated with the downlink reference signal (e.g., SS / PBCH block). Specifically, the beamwidth of each CSI-RS resource is substantially half of the beamwidth of the downlink reference signal associated with the PRACH preamble and RACH opportunity. That is, this association associates multiple (e.g., two) CSI-RS resources with a set of PRACH preambles and RACH opportunities.

[0062] As Figure 5 shown, according to this association, the first and second CSI-RS resources correspond to the first set of PRACH preambles and RACH opportunities, and thus, the beams for the first and second CSI-RS resources correspond to the beams for the first set of PRACH preambles and RACH opportunities. According to this association, the third and fourth CSI-RS resources correspond to the second set of PRACH preambles and RACH opportunities, and thus, the beams for the third and fourth CSI-RS resources correspond to the beams for the second set of PRACH preambles and RACH opportunities. According to this association, the fifth and sixth CSI-RS resources correspond to the third set of PRACH preambles and RACH opportunities, and thus the beams for the fifth and sixth CSI-RS resources correspond to the beams for the third set of PRACH preambles and RACH opportunities. According to this association, the seventh and eighth CSI-RS resources correspond to the fourth set of PRACH preambles and RACH opportunities, and thus, the beams for the seventh and eighth CSI-RS resources correspond to the beams for the fourth set of PRACH preambles and RACH opportunities.

[0063] In another embodiment, an association is configured between the CSI-RS resource and the PRACH preamble. For example, the first and second CSI-RS resources are associated with the first set of PRACH preambles, the third and fourth CSI-RS resources are associated with the second set of PRACH preambles, and so on. In another embodiment, an association is configured between the CSI-RS resource and the RACH opportunity. For example, the first and second CSI-RS resources are associated with the first RACH opportunity, the third and fourth CSI-RS resources are associated with the second RACH opportunity, and so on.

[0064] That is, for purposes not limited to beam failure recovery, identifying new beams and handovers, an association is configured between the CSI-RS resource and the RACH resource including the preamble, opportunity (e.g., time-frequency resource) or a combination thereof.

[0065] The advantage of this association (i.e., the mapping of multiple CSI-RS resources to a set of PRACH preambles and RACH opportunities) is that fewer PRACH resources are required. The disadvantage of this association is that the new beam information is only partially transmitted through the first step of the random access procedure, and wider beams are used for the message in the third step (i.e., the scheduling request) and the message in the fourth step (i.e., the contention resolution) of the contention-based random access procedure. However, the transmission of the new beam information can be completed through the message in the third step (i.e., the uplink transmission) of the contention-based random access procedure.

[0066] Figure 6 is a schematic diagram showing the association between CSI-RS resources and multiple sets of PRACH preambles and RACH opportunities according to another embodiment of the present application.

[0067] In this embodiment, this association associates CSI-RS resources with PRACH preamble groups and RACH opportunities through Code Division Multiplexing (CDM).

[0068] As Figure 6 shown, there are at least two sets of PRACH preambles at each RACH opportunity, where the preambles from two PRACH preamble groups can be distinguished in the code domain (i.e., the preamble domain).

[0069] The first and second CSI-RS resources respectively correspond to the first and second sets of PRACH preambles within the first RACH opportunity. The third and fourth CSI-RS resources respectively correspond to the first and second sets of PRACH preambles within the second RACH opportunity. The fifth and sixth CSI-RS resources respectively correspond to the first and second sets of PRACH preambles within the third RACH opportunity. The seventh and eighth CSI-RS resources respectively correspond to the first and second sets of PRACH preambles within the fourth RACH opportunity.

[0070] Figure 7 is a schematic diagram showing the association between CSI-RS resources and multiple PRACH preambles and RACH opportunities according to yet another embodiment of the present application.

[0071] In this embodiment, this association associates one CSI-RS resource with a set of RACH opportunities through Frequency Division Multiplexing (FDM).

[0072] As Figure 7 shown, there are two RACH opportunities in each PRACH time period, where the two RACH opportunities can be distinguished in the frequency domain.

[0073] The first CSI-RS resource and the second CSI-RS resource respectively correspond to the first RACH opportunity and the second RACH opportunity within the first PRACH time period. The third CSI-RS resource and the fourth CSI-RS resource respectively correspond to the first RACH opportunity and the second RACH opportunity within the second PRACH time period. The fifth CSI-RS resource and the sixth CSI-RS resource respectively correspond to the first RACH opportunity and the second RACH opportunity within the third PRACH time period. The seventh CSI-RS resource and the eighth CSI-RS resource respectively correspond to the first RACH opportunity and the second RACH opportunity within the fourth PRACH time period.

[0074] Figure 8 It is a schematic diagram showing the association between CSI-RS resources and multiple PRACH preambles and RACH opportunities according to another embodiment of the present application.

[0075] In this embodiment, the association associates one CSI-RS resource with a group of PRACH preambles and RACH opportunities through time division multiplexing (TDM).

[0076] As Figure 8 shown, four RACH opportunities are replicated in the time domain, and each of the eight RACH opportunities can be distinguished in the time domain with the same frequency range.

[0077] The first CSI-RS resource and the second CSI-RS resource respectively correspond to the first RACH opportunity within the first time period of the time domain and the first RACH opportunity within the second time period of the time domain. The third CSI-RS resource and the fourth CSI-RS resource respectively correspond to the second RACH opportunity within the first time period of the time domain and the second RACH opportunity within the second time period of the time domain. The fifth CSI-RS resource and the sixth CSI-RS resource respectively correspond to the third RACH opportunity within the first time period of the time domain and the third RACH opportunity within the second time period of the time domain. The seventh CSI-RS resource and the eighth CSI-RS resource respectively correspond to the fourth RACH opportunity within the first time period of the time domain and the fourth RACH opportunity within the second time period of the time domain.

[0078] Figures 6 to 8The advantages of the association are as follows: Through the first step of the random access procedure, new beam information can be fully transmitted, and for the messages in the third step (i.e., uplink transmission) and the fourth step (e.g., contention resolution) of the contention-based random access procedure, a narrower beam can be used (a narrower beam can provide better spectral efficiency). Note that the association between the downlink reference signals (i.e., CSI-RS resources and / or SS / PBCH blocks) and multiple sets of PRACH preambles and / or RACH opportunities can be based on the above CDM, FDM, and TDM methods.

[0079] Figure 9 FIG. is a schematic diagram showing a joint PRACH design for beam failure recovery and other uplink requests or indications according to an embodiment of the present application.

[0080] In this embodiment, dedicated preambles can be allocated for beam failure recovery and other uplink requests or indications, such as scheduling requests or acknowledgment (ACK) or non-acknowledgment (NACK) signals.

[0081] Specifically, when transmitted on one of the serving beams (denoted as beam 1 in Figure 9 ), the dedicated preamble serves as a scheduling request or ACK / NACK signal. When transmitted on one of the non-serving beams (denoted as beams 2 to 4 in Figure 9 ), the dedicated preamble serves as a request for beam failure recovery.

[0082] As Figure 9 shown, when transmitted on beam 1 (i.e., the serving beam), the preamble can serve as a scheduling request SR, and when transmitted on beam 4 (i.e., the non-serving beam), the preamble can serve as a request for beam failure recovery.

[0083] Note that in the present application, a more flexible PRACH design for improving the utilization efficiency of PRACH resources is proposed. For example, different preambles can be flexibly segmented for asynchronous and synchronous transmissions within a RACH opportunity, by using a preamble format with a smaller sequence length or configuring a smaller subcarrier spacing to reduce the bandwidth for synchronous transmission, such that the bandwidth for synchronous transmission is narrower than that for asynchronous transmission, and / or the cyclic shift for synchronous transmission can be reduced to be less than that for asynchronous transmission.

[0084] Figure 10 FIG. is a schematic diagram showing the utilization of PRACH resources for asynchronous and synchronous transmissions according to an embodiment of the present application.

[0085] As Figure 10 shown, there are four different PRACH configurations for the same PRACH time-frequency resource. In the first PRACH configuration (in Figure 10In the remaining PRACH configurations (denoted as Config.1 to Config.3 in

[0086] ), the preambles generated using all Zadoff-Chu (ZC) roots are separated for asynchronous and synchronous transmissions within the same PRACH time-frequency resource, and the PRACH resource blocks for asynchronous transmissions using different preambles are denoted as Async.B5 to Async.B6, while the PRACH resource blocks for synchronous transmissions using different preambles are denoted as Sync.B1 to Sync.B2. Figure 10 In the remaining PRACH configurations (denoted as Config.1 to Config.3 in

[0087] Table 1 provides examples of the number of preambles and ZC roots for asynchronous and synchronous transmissions in each PRACH configuration as follows (assuming the PRACH subcarrier spacing (SCS) is 30 KHz and the inter-site distance (ISD) is 500 meters).

[0088]

[0089] Table 1.

[0090] For an uplink synchronous PRACH attempt or a PRACH attempt not followed by a Physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH) transmission, the gNB does not need to include a Timing Advance (TA) command and a Temporary Cell Radio Network Temporary Identifier (C-RNTI) to respond to these PRACH attempts.

[0091] Figure 11 is a schematic diagram showing the PRACH preamble bandwidth for asynchronous and synchronous transmissions according to an embodiment of the present application.

[0092] In Figure 11 the left side of Figure 11On the right side of [Figure] is shown the PRACH time-frequency resource for synchronous transmission (where TA estimation is not required), where the number of ZC roots is 2 and the length of the preamble sequence is 139. That is, the PRACH preamble bandwidth for synchronous transmission is narrower than that for asynchronous transmission. In other words, the PRACH bandwidth can be reduced by configuring a preamble format with a smaller sequence length or by configuring a smaller subcarrier spacing.

[0093] Since the preamble sequence is shortened and the number of ZC roots within the PRACH time-frequency resource for synchronous transmission is reduced, the multiple access interference (MAI) from other root sequences can be reduced.

[0094] In addition, since TA estimation is not required for synchronous PRACH transmission, the cyclic shift does not need to cover the round-trip propagation delay, and the cyclic shift used to generate the preamble is reduced.

[0095] Alternatively, the PRACH preamble bandwidth and cyclic shift for synchronous transmission can be reduced to be less than those for asynchronous transmission.

[0096] Figure 12 is a schematic diagram showing the PRACH resource utilization for asynchronous and synchronous transmission according to another embodiment of the present application.

[0097] The PRACH time-frequency resource for asynchronous transmission is shown on the left side of [Figure], where the number of ZC roots is 8, the length of the preamble sequence is 839, and the cyclic shift Ncs is 9. The PRACH time-frequency resource for synchronous transmission is shown on the right side of [Figure], where the number of ZC roots is 2, the length of the preamble sequence is 139, and the cyclic shift Ncs is 2. Figure 12 On the right side of [Figure] is shown, there are multiple PRACH time-frequency resources for synchronous transmission allocated within the same PRACH time period. Advantageously, such an allocation can provide the desired preamble opportunities without introducing severe MAI from other root sequences. Figure 12 On the right side of [Figure] is shown, there are multiple PRACH time-frequency resources for synchronous transmission allocated within the same PRACH time period. Advantageously, such an allocation can provide the desired preamble opportunities without introducing severe MAI from other root sequences.

[0098] As Figure 12 shown on the right side of [Figure], there are multiple PRACH time-frequency resources for synchronous transmission allocated within the same PRACH time period. Advantageously, such an allocation can provide the desired preamble opportunities without introducing severe MAI from other root sequences.

[0099] In view of the foregoing embodiments, it will be appreciated that the present application identifies beams by providing an association between downlink reference signals (e.g., CSI-RS resources, and / or SS / PBCH blocks) and PRACH resources (including PRACH preamble groups, RACH occasions, or any combination thereof) to achieve beam failure recovery or beam switching through PRACH. Moreover, the present application enables a flexible PRACH design by allowing for flexible partitioning of different preambles within the PRACH time-frequency resources for asynchronous and synchronous transmissions, and / or reducing the bandwidth and / or cyclic shift for synchronous transmissions to be less than those for asynchronous transmissions. Advantageously, the spectrum efficiency and PRACH utilization can be significantly improved.

[0100] Although the present application has been described by way of examples and preferred embodiments, it should be understood that the present application is not limited thereto. Those skilled in the art can still make various changes and modifications without departing from the scope and spirit of the present application. Therefore, the scope of the present application should be defined and protected by the following claims and their equivalents.

[0101] The use of ordinal terms such as "first", "second", etc. in the claims to modify the elements of the claims themselves does not mean a priority or rank or order of one claim element relative to another claim element, or the chronological order of performing the acts of the method, but is only used as a label to distinguish one claim element having a specific name from another element having the same name (but using an ordinal term) to distinguish the claim elements.

Claims

1. A user equipment, comprising: A wireless transceiver for performing wireless transmission to and wireless reception from a cellular station; A controller for performing a synchronous transmission to the cellular station on a Physical Random Access Channel (PRACH) via the wireless transceiver using one or more first preambles, or for performing an asynchronous or synchronous transmission to the cellular station on the PRACH via the wireless transceiver using one or more second preambles; Wherein, the controller is further configured to receive, via the wireless transceiver, a response to the synchronous transmission from the cellular station; Timing Advance (TA) estimation is not required for the synchronous transmission.

2. The user equipment according to claim 1, wherein, The controller uses one or more first preambles via the wireless transceiver to perform a synchronous transmission to the cellular station on the PRACH, and uses one or more second preambles via the wireless transceiver to perform an asynchronous or synchronous transmission to the cellular station on the PRACH.

3. The user equipment according to claim 2, wherein, The number of Zadoff-Chu (ZC) roots for generating preambles for synchronous transmission is less than the number of ZC roots for generating preambles for asynchronous transmission.

4. The user equipment according to claim 2, wherein, The cyclic shift applied to generate a preamble for synchronous transmission is less than the cyclic shift applied to generate a preamble for asynchronous transmission.

5. The user equipment according to claim 1, wherein, The response does not include a Timing Advance command (TA) and a Temporary Cell Radio Network Temporary Identity (C-RNTI).

6. The user equipment according to claim 2, wherein, The bandwidth required for the synchronous transmission is narrower than the bandwidth required for the asynchronous transmission.

7. A method for effectively utilizing the PRACH, which is executed by a user equipment wirelessly connected to a cellular station, the method comprising: Using one or more first preambles to perform a synchronous transmission to the cellular station on the PRACH; Or, Using one or more second preambles to perform an asynchronous or synchronous transmission to the cellular station on the PRACH; And Receiving, from the cellular station, a response to the synchronous transmission; wherein, TA estimation is not required for the synchronous transmission.

8. The method according to claim 7, wherein, The user equipment uses one or more first preambles to perform a synchronous transmission to the cellular station on the PRACH; and uses one or more second preambles to perform an asynchronous or synchronous transmission to the cellular station on the PRACH.

9. The method according to claim 8, wherein, The number of ZC roots for generating preambles for synchronous transmission is less than the number of ZC roots for generating preambles for asynchronous transmission.

10. The method according to claim 8, wherein, The cyclic shift applied to generate a preamble for synchronous transmission is less than the cyclic shift applied to generate a preamble for asynchronous transmission.

11. The method according to claim 7, further comprising: The response does not include a Timing Advance command and a Temporary Cell Radio Network Temporary Identity.

12. The method according to claim 8, further comprising: The bandwidth required for the synchronous transmission is narrower than the bandwidth required for the asynchronous transmission.

13. A cellular station, comprising: A wireless transceiver for performing wireless transmission to and wireless reception from a cellular station; And A controller for configuring one or more first preambles for a user equipment to perform synchronous transmission on a PRACH, configuring one or more second preambles for the user equipment to perform asynchronous transmission or synchronous transmission on the PRACH, and transmitting, via the wireless transceiver, the configurations of the first preambles and the second preambles to the user equipment; wherein the controller is further configured to transmit, via the wireless transceiver, a response to the synchronous transmission to the user equipment; wherein TA estimation is not required for the synchronous transmission.

14. The cellular station according to claim 13, wherein, The number of ZC roots for generating preambles for synchronous transmission is less than the number of ZC roots for generating preambles for asynchronous transmission.

15. The cellular station according to claim 13, wherein, The cyclic shift applied to generate a preamble for synchronous transmission is less than the cyclic shift applied to generate a preamble for asynchronous transmission.

16. The cellular station according to claim 13, wherein, The response does not include a timing advance command and a temporary cell radio network temporary identifier.

17. The cellular station according to claim 13, wherein, The bandwidth required for the synchronous transmission is narrower than the bandwidth required for the asynchronous transmission.

18. A method for efficiently utilizing a PRACH, the method being performed by a cellular station wirelessly connected to a user equipment, the method comprising: Configuring one or more first preambles for the user equipment to perform synchronous transmission on the PRACH; Configuring one or more second preambles for the user equipment to perform asynchronous transmission or synchronous transmission on the PRACH; and Transmitting the configurations of the first preambles and the second preambles to the user equipment; Sending a response to the synchronous transmission to the user equipment, wherein TA estimation is not required for the synchronous transmission.

19. The method according to claim 18, wherein, The number of ZC roots for generating preambles for synchronous transmission is less than the number of ZC roots for generating preambles for asynchronous transmission.

20. The method according to claim 18, wherein, The cyclic shift applied to generate a preamble for synchronous transmission is less than the cyclic shift applied to generate a preamble for asynchronous transmission.

21. The method according to claim 18, wherein, Further comprising: The response does not include a timing advance command and a temporary cell radio network temporary identifier.

22. The method according to claim 18, wherein, The bandwidth required for the synchronous transmission is narrower than the bandwidth required for the asynchronous transmission.

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