Random access response and contention resolution

Abstract

A base station and user equipment (UE) for random access and contention resolution are provided. A method for operating a UE includes receiving a configuration for: a first control resource set (CORESET) including a first number of resource blocks (RBs) in a frequency domain and a first number of symbols in a time domain; a second CORESET including RBs of a second number of RBs in the frequency domain and symbols of a second number of symbols in the time domain; and a reference signal received power (RSRP) threshold. The method also includes determining a first RSRP value and receiving a first physical downlink control channel (PDCCH). The first PDCCH reception is in the first CORESET when the first RSRP value is greater than the RSRP threshold, and the first PDCCH reception is in the second CORESET when the first RSRP value is less than the RSRP threshold.

Description

Technical Field

[0001] The present disclosure generally relates to wireless communication systems, and more particularly, to random access responses and contention resolution. Background Art

[0002] In consideration of the generations of development of wireless communication, technologies mainly for services for humans, such as voice calls, multimedia services, and data services, have been developed. After the commercialization of the 5G (5th generation) communication system, the number of connected devices is expected to grow exponentially. These will be increasingly connected to the communication network. Examples of connected things may include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve in various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In order to connect hundreds of billions of devices and things in the 6G (6th generation) era to provide various services, efforts have been made to develop an improved 6G communication system. For these reasons, the 6G communication system is called the ultra 5G system.

[0003] The 6G communication system, which is expected to be commercialized around 2030, will have a peak data rate of tera (1,000 giga) - level bps and a radio latency of less than 100 μsec, and thus will be 50 times faster and have 1 / 10 of the radio latency of the 5G communication system.

[0004] In order to achieve such high data rates and ultra - low latencies, it has been considered to implement the 6G communication system in the terahertz band (e.g., 95 GHz to 3 THz band). Since path loss and atmospheric absorption in the terahertz band are expected to be more severe than in the millimeter - wave band introduced in 5G, technologies for ensuring signal transmission distance (i.e., coverage) will become more critical. As the main technology for ensuring coverage, it is necessary to develop radio frequency (RF) components, antennas, new waveforms with better coverage than the orthogonal frequency - division multiplexing (OFDM) scheme, beamforming and massive multiple - input multiple - output (MIMO), full - dimensional MIMO (FD - MIMO), array antennas, and multi - antenna transmission technologies such as massive antennas. In addition, new technologies for improving the coverage of terahertz - band signals, such as metasurface - based lenses and antennas, orbital angular momentum (OAM), and reconfigurable intelligent surfaces (RIS), have been discussed.

[0005] In addition, to improve spectral efficiency and overall network performance, the following technologies for 6G communication systems have been developed: full-duplex technology for enabling uplink and downlink transmissions to simultaneously use the same frequency resources at the same time; network technologies for integrally utilizing satellites, high-altitude platform stations (HAPS), etc.; improved network architectures for supporting mobile base stations, etc. and achieving network operation optimization and automation, etc.; dynamic spectrum sharing technology via collision avoidance based on prediction of spectrum usage; use of artificial intelligence (AI) in wireless communication for improving overall network operation by leveraging AI from the design phase of developing 6G and internalizing end-to-end AI support functions; next-generation distributed computing technology for overcoming the limits of UE computing capabilities through achievable ultra-high-performance communication and resources on the computing network such as mobile edge computing (MEC), cloud, etc. Additionally, continuous attempts are made to strengthen connectivity between devices, optimize the network, promote softwareization of network entities, and increase the openness of wireless communication by designing new protocols to be used in 6G communication networks, developing mechanisms for implementing hardware-based secure environments and secure use of data, and developing technologies for maintaining privacy.

[0006] Research and development on the hyper-connected 6G communication system (including person-to-machine (P2M) and machine-to-machine (M2M)) are expected to realize the next hyper-connected experience. In particular, services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas are expected to be provided through the 6G communication system. Additionally, services such as remote surgery, industrial automation, and emergency response with enhanced security and reliability will be provided through the 6G communication system, enabling the application of technologies in various fields such as industry, healthcare, automotive, and household appliances.

[0007] The initial commercialization of 5G mobile communication is expected around 2020, and its momentum has been increasing recently with all the technical activities worldwide for various candidate technologies from industry and academia. Candidate enablers of 5G / NR mobile communication include massive antenna technology, from legacy cellular bands to high frequencies, to provide beamforming gain and support increased capacity, new waveforms (e.g., new radio access technology (RAT)) for flexibly adapting to various services / applications with different requirements, new multiple access schemes for supporting massive connectivity, and so on. SUMMARY OF THE INVENTION

[0008] SOLUTION TO THE PROBLEM

[0009] The present disclosure relates to a wireless communication system, and more particularly, the present disclosure relates to random access response and contention resolution.

[0010] In one embodiment, a method for operating a user equipment (UE) is provided. The method includes receiving configurations for: a first control resource set (CORESET), the first CORESET including a number of resource blocks (RBs) of a first number of RBs in the frequency domain and a number of symbols of a first number of symbols in the time domain; a second CORESET, the second CORESET including a second number of RBs in the frequency domain and a second number of symbols in the time domain; and a reference signal received power (RSRP) threshold. The second number of symbols is greater than the first number of symbols. The method further includes determining a first RSRP value and receiving a first physical downlink control channel (PDCCH). When the first RSRP value is greater than the RSRP threshold, the first PDCCH reception is in the first CORESET, and when the first RSRP value is less than the RSRP threshold, the first PDCCH reception is in the second CORESET.

[0011] In another embodiment, a UE is provided. The UE includes: a transceiver configured to receive configurations for: a first CORESET, the first CORESET including a number of RBs of a first number of RBs in the frequency domain and a number of symbols of a first number of symbols in the time domain, a second CORESET, the second CORESET including a second number of RBs in the frequency domain and a second number of symbols in the time domain; and an RSRP threshold. The second number of symbols is greater than the first number of symbols. The UE further includes a processor configured to determine a first RSRP value. The transceiver is further configured to receive a first PDCCH. When the first RSRP value is greater than the RSRP threshold, the first PDCCH reception is in the first CORESET, and when the first RSRP value is less than the RSRP threshold, the first PDCCH reception is in the second CORESET.

[0012] In yet another embodiment, a base station is provided. The base station includes a processor and a transceiver operatively connected to the processor. The transceiver is configured to transmit configurations for: a first CORESET, the first CORESET including a number of RBs of a first number of RBs in the frequency domain and a number of symbols of a first number of symbols in the time domain, a second CORESET, the second CORESET including a second number of RBs in the frequency domain and a second number of symbols in the time domain; and an RSRP threshold. The second number of symbols is greater than the first number of symbols. The transceiver is further configured to transmit a first PDCCH. The first PDCCH transmission is in the first CORESET or in the second CORESET. The first PDCCH transmission schedules the transmission of a physical downlink shared channel (PDSCH) including a random access response (RAR) message. Description of the Drawings

[0013] To understand the present disclosure and its advantages more fully, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

[0014] Figure 1 Shows an example wireless network according to an embodiment of the present disclosure;

[0015] Figure 2 Shows an example gNB according to an embodiment of the present disclosure;

[0016] Figure 3 Shows an example UE according to an embodiment of the present disclosure;

[0017] Figure 4 Shows an example DL slot structure according to an embodiment of the present disclosure;

[0018] Figure 5 Shows an example UL slot structure for PUSCH transmission or PUCCH transmission according to an embodiment of the present disclosure;

[0019] Figure 6A Shows an example E / R / R / BI MAC sub - header according to an embodiment of the present disclosure;

[0020] Figure 6B Shows an example E / T / RAPID MAC sub - header according to an embodiment of the present disclosure;

[0021] Figure 6C Shows an example MAC RAR according to an embodiment of the present disclosure;

[0022] Figure 7 Shows an example determination of the number of repetitions of PDSCH transmission for providing RAR based on RSRP range / CE level and UE power class according to an embodiment of the present disclosure;

[0023] Figure 8 Shows an example determination of the CORESET length for PDCCH monitoring associated with receiving a PDSCH for scheduling RAR provided by a UE based on RSRP range / CE level and UE power class according to an embodiment of the present disclosure;

[0024] Figure 9 Shows an example determination of the start symbol and length of the PDCCH monitoring window for receiving a PDSCH for scheduling RAR in the case of PRACH preamble transmission with repetition according to an embodiment of the present disclosure;

[0025] Figure 10Shows another example determination of the start symbol and length of a PDCCH monitoring window for receiving a PDSCH for scheduling an RAR in the case of repeated PRACH preamble transmissions according to an embodiment of the present disclosure; and

[0026] Figure 11 Shows example congestion control and UE distribution during the initial access of an NR-Light UE according to an embodiment of the present disclosure. Detailed Description

[0027] By the following drawings, description, and claims, other technical features may be apparent to those skilled in the art.

[0028] Before proceeding with the following modes of the invention, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term "couple" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with each other. The terms "transmit," "receive," and "communicate" and their derivatives cover both direct and indirect communication. The terms "include" and "including" and their derivatives mean including but not limited to. The term "or" is inclusive and means and / or. The phrase "associated with" and its derivatives mean including, being included within, interconnecting with, containing, being contained within, connected to or connecting with, coupled to or coupling with, capable of communicating with, cooperating with, interlacing, juxtaposing, being adjacent to, being bound to or binding with, having, having the property of, having a relationship with or being related to, etc. The term "controller" refers to any device, system, or portion thereof that controls at least one operation. Such a controller may be implemented in hardware or in a combination of hardware and software and / or firmware. Whether local or remote, the functions associated with any particular controller may be centralized or distributed. The phrase "at least one of" when used with a list of items means that different combinations of one or more of the listed items may be used and only one item from the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A; B; C; A and B; A and C; B and C; and A and B and C.

[0029] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed of computer-readable program code and embodied in a computer-readable medium. The terms "application program" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, related data, or portions thereof that are adapted to be implemented with appropriate computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, optical disc (CD), digital video disc (DVD), or any other type of memory. A "non-transitory" computer-readable medium excludes wired, wireless, optical, or other communication links that transmit transient electrical signals or other transient signals. Non-transitory computer-readable media include media in which data can be permanently stored and media in which data can be stored and then rewritten, such as rewritable optical discs or erasable memory devices.

[0030] Certain other words and phrases are defined throughout this patent document. Those of ordinary skill in the art should understand that, in many if not most instances, such definitions apply to the prior as well as future use of such defined words and phrases.

[0031] As discussed below Figures 1 to 11 and the various embodiments used to describe the principles of the present disclosure in this patent document are merely exemplary and should not be construed in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any suitably arranged system or device.

[0032] The following documents are hereby incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 38.211 v15.6.0, "NR; Physical channels and modulation"; 3GPP TS 38.212 v15.6.0, "NR; Multiplexing and Channel coding"; 3GPP TS 38.213 v15.6.0, "NR; Physical Layer Procedures for Control"; 3GPP TS 38.214 v15.6.0, "NR; Physical Layer Procedures for Data"; 3GPP TS 38.321 v15.6.0, "NR; Medium Access Control (MAC) protocol specification"; and 3GPP TS 38.331 v15.6.0, "NR; Radio Resource Control (RRC) Protocol Specification".

[0033] The following Figures 1 to 3 describes various embodiments implemented in a wireless communication system and using orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication techniques. Figures 1 to 3 The description is not intended to imply physical or architectural limitations on the ways in which different embodiments may be implemented. Different embodiments of the present disclosure may be implemented in any suitably arranged communication system.

[0034] Figure 1 shows an example wireless network according to an embodiment of the present disclosure. Figure 1 The illustrated embodiment of the wireless network is for illustrative purposes only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present disclosure.

[0035] As Figure 1 shown, the wireless network includes gNBs 101 (e.g., base station BS), 102, and 103. gNB 101 communicates with gNBs 102 and 103. gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0036] gNB 102 provides wireless broadband access to network 130 for a first plurality of user equipments (UEs) located within coverage area 120 of gNB 102. The first plurality of UEs includes: UE 111, which may be located in a small business; UE 112, which may be located in an enterprise (E); UE 113, which may be located in a WiFi hotspot (HS); UE 114, which may be located in a first residence (R); UE 115, which may be located in a second residence (R); and UE 116, which may be a mobile device (M), such as a cellular phone, a wireless laptop computer, a wireless PDA, etc. gNB 103 provides wireless broadband access to network 130 for a second plurality of UEs within coverage area 125 of gNB 103. The second plurality of UEs includes UE 115 and UE 116. In some embodiments, one or more of eNBs 101 to 103 may communicate with each other and with UEs 111 - 116 using 5G / NR, LTE, LTE-A, WiMAX, WiFi, or other wireless communication technologies.

[0037] Depending on the network type, the term "base station" or "BS" may refer to any component (or collection of components) configured to provide wireless access to a network, such as a transmit point (TP), a transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G / NR base station (gNB), a macro base station, a femto base station, a WiFi access point (AP), or other wireless-capable device. A base station may provide wireless access according to one or more wireless communication protocols, e.g., 5G / NR 3GPP new radio interface / access (NR), Long Term Evolution (LTE), LTE advanced (LTE-A), High Speed Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For convenience, the terms "BS" and "TRP" may be used interchangeably in this patent document to refer to the network infrastructure components that provide wireless access to remote terminals. Additionally, depending on the network type, the term "user equipment" or "UE" may refer to any component, such as a "mobile station", "subscriber station", "remote terminal", "wireless terminal", "reception point", or "user equipment". For convenience, the terms "user equipment" and "UE" are used in this patent document to refer to the remote wireless devices that wirelessly access a BS, whether the UE is a mobile device (such as a mobile phone or a smart phone) or is generally considered a stationary device (such as a desktop computer or a vending machine).

[0038] The dashed lines illustrate the approximate extents of coverage areas 120 and 125, which are shown as being generally circular for purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with a gNB (such as coverage areas 120 and 125) may have other shapes, including irregular shapes, depending on the configuration of the gNB and changes in the radio environment associated with natural and man-made obstacles.

[0039] As described in more detail below, one or more of UEs 111 to 116 include circuitry, programming, or a combination thereof for efficient random access response and contention resolution for the UE. In certain embodiments, one or more of gNBs 101 to 103 also include circuitry, programming, or a combination thereof for efficient random access response and contention resolution for the UE.

[0040] Although Figure 1 an example of a wireless network is shown, various changes may be made to Figure 1 it. For example, the wireless network may include any number of gNBs and any number of UEs arranged in any suitable manner. Additionally, gNB 101 may communicate directly with any number of UEs and provide those UEs with wireless broadband access to network 130. Similarly, each of gNBs 102 to 103 may communicate directly with network 130 and provide the UEs with direct wireless broadband access to network 130. Further, gNB 101, gNB 102, and / or gNB 103 may provide access to other or additional external networks (such as an external telephone network or other types of data networks).

[0041] Figure 2 An example gNB 102 according to an embodiment of the present disclosure is shown. Figure 2 The embodiment of gNB 102 shown in Figure 1 is for illustrative purposes only, and Figure 2 gNBs 101 and 103 may have the same or similar configurations. However, gNBs have a wide variety of configurations, and

[0042] As Figure 2 shown, gNB 102 includes a plurality of antennas 205a to 205n, a plurality of RF transceivers 210a to 210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. gNB 102 also includes a controller / processor 225, a memory 230, and a backhaul or network interface 235.

[0043] RF transceivers 210a to 210n receive incoming RF signals from antennas 205a to 205n, such as signals transmitted by UEs in network 100. RF transceivers 210a to 210n down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are sent to RX processing circuitry 220, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. RX processing circuitry 220 transmits the processed baseband signal to controller / processor 225 for further processing.

[0044] TX processing circuitry 215 receives analog or digital data (such as voice data, network data, email, or interactive video game data) from controller / processor 225. TX processing circuitry 215 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. RF transceivers 210a to 210n receive the outgoing processed baseband or IF signal from TX processing circuitry 215 and up-convert the baseband or IF signal to an RF signal transmitted via antennas 205a to 205n.

[0045] Controller / processor 225 may include one or more processors or other processing devices that control the overall operation of gNB 102. For example, controller / processor 225 may control the reception of forward channel signals and the transmission of reverse channel signals by RF transceivers 210a to 210n, RX processing circuitry 220, and TX processing circuitry 215 according to well-known principles. Controller / processor 225 may also support additional functions, such as more advanced wireless communication functions. For example, controller / processor 225 may support beamforming or directional routing operations, in which outgoing / incoming signals from / to multiple antennas 205a to 205n are weighted differently to effectively direct the outgoing signal in the desired direction. Controller / processor 225 may support any one of a wide variety of other functions in gNB 102.

[0046] Controller / processor 225 is also capable of executing programs and other processes residing in memory 230, such as an OS. Controller / processor 225 may move data into or out of memory 230 as required by the executing processes.

[0047] The controller / processor 225 is also connected to a backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems via a backhaul connection or network. The interface 235 can support communication over any appropriate wired or wireless connection. For example, when the gNB 102 is implemented as part of a cellular communication system (such as a cellular communication system supporting 5G / NR, LTE, or LTE-A), the interface 235 can allow the gNB 102 to communicate with other gNBs via a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 can allow the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface 235 includes any suitable structure that supports communication over a wired or wireless connection, such as an Ethernet or RF transceiver.

[0048] Memory 230 is coupled to controller / processor 225. A portion of memory 230 may include RAM, and another portion of memory 230 may include flash memory or other ROM.

[0049] Although Figure 2 An example of a gNB 102 is shown, but Figure 2 For example, gNB 102 may include any number of Figure 2 As a specific example, the access point may include multiple interfaces 235, and the controller / processor 225 may support routing functions to route data between different network addresses. As another specific example, although shown as including a single instance of TX processing circuitry 215 and a single instance of RX processing circuitry 220, the gNB 102 may include multiple instances of each (such as one instance per RF transceiver). In addition, Figure 2 The various components in may be combined, further subdivided, or omitted, and additional components may be added according to specific needs.

[0050] Figure 3 An example UE 116 is shown in accordance with an embodiment of the present disclosure. Figure 3 The embodiment of UE 116 shown in FIG. 1 is for illustration only, and Figure 1 UEs 111 to 115 may have the same or similar configurations. However, UEs have a wide variety of configurations, and Figure 3 The scope of the present disclosure is not limited to any particular implementation of a UE.

[0051] like Figure 3As shown, UE 116 includes antenna 305, radio frequency (RF) transceiver 310, TX processing circuitry 315, microphone 320, and receive (RX) processing circuitry 325. UE 116 also includes speaker 330, processor 340, input / output (I / O) interface (IF) 345, touch screen 350, display 355, and memory 360. Memory 360 includes operating system (OS) 361 and one or more application programs 362.

[0052] RF transceiver 310 receives incoming RF signals transmitted by gNB of network 100 from antenna 305. RF transceiver 310 down-converts the incoming RF signals to generate intermediate frequency (IF) or baseband signals. The IF or baseband signals are sent to RX processing circuitry 325, which generates processed baseband signals by filtering, decoding, and / or digitizing the baseband or IF signals. RX processing circuitry 325 transmits the processed baseband signals to speaker 330 (such as for voice data) or processor 340 for further processing (such as for web browsing data).

[0053] TX processing circuitry 315 receives analog or digital voice data from microphone 320, or other outgoing baseband data (such as network data, e-mail, or interactive video game data) from processor 340. TX processing circuitry 315 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate processed baseband or IF signals. RF transceiver 310 receives the outgoing processed baseband or IF signals from TX processing circuitry 315 and up-converts the baseband or IF signals to RF signals transmitted via antenna 305.

[0054] Processor 340 may include one or more processors or other processing devices, and executes OS 361 stored in memory 360 to control the overall operation of UE 116. For example, processor 340 may control the reception of forward channel signals and the transmission of reverse channel signals by RF transceiver 310, RX processing circuitry 325, and TX processing circuitry 315 according to well-known principles. In some embodiments, processor 340 includes at least one microprocessor or microcontroller.

[0055] The processor 340 is also capable of executing other processes and programs residing in the memory 360, such as processes for beam management. The processor 340 can move data into or out of the memory 360 as required by the executing processes. In some embodiments, the processor 340 is configured to execute the application program 362 based on the OS 361 or in response to signals received from the gNB or the operator. The processor 340 is also coupled to an I / O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. The I / O interface 345 is a communication path between these accessories and the processor 340.

[0056] The processor 340 is also coupled to a touch screen 350 and a display 355. An operator of the UE 116 can use the touch screen 350 to input data to the UE 116. The display 355 can be a liquid crystal display, a light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as from a website.

[0057] The memory 360 is coupled to the processor 340. A portion of the memory 360 can include random access memory (RAM), and another portion of the memory 360 can include flash memory or other read-only memory (ROM).

[0058] Although Figure 3 an example of the UE 116 is shown, various changes can be made to Figure 3 it. For example, Figure 3 the various components in Figure 3 can be combined, further subdivided, or omitted, and additional components can be added according to specific requirements. As a specific example, the processor 340 can be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Additionally, although

[0059] To meet the increasing wireless data service demands since the deployment of 4G communication systems, efforts have been made to develop an improved 5G / NR or pre-5G / NR communication system. Therefore, the 5G / NR or pre-5G / NR communication system is also referred to as the "Ultra 4G network" or "Post-LTE system". The 5G / NR communication system is considered to be implemented in a higher frequency (millimeter wave) band (e.g., 60 GHz band) to achieve higher data rates, or in a lower frequency band (such as 6 GHz) to allow for robust coverage. To reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large antenna technologies are discussed in the 5G / NR communication system.

[0060] In addition, in the 5G / NR communication system, system network improvements based on advanced small cells, cloud radio access network (RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, mobile network, cooperative communication, coordinated multi-point (CoMP), receiver interference cancellation, etc. are being developed.

[0061] A communication system includes a downlink (DL) and an uplink (UL). The downlink (DL) refers to the transmission from a base station or one or more transmission points to a UE, and the uplink (UL) refers to the transmission from the UE to a base station or one or more receiving points.

[0062] The time unit for DL signaling or UL signaling on a cell is called a time slot and can include one or more symbols. The symbol can also be used as an additional time unit. The frequency (or bandwidth (BW)) unit is called a resource block (RB). One RB includes multiple subcarriers (SC). For example, a time slot can have a duration of 0.5 milliseconds or 1 millisecond, include 14 symbols, and an RB can include 12 SCs with an SC spacing of 15 KHz or 30 KHz, etc.

[0063] DL signals include a data signal that conveys information content, a control signal that conveys DL control information (DCI), and a reference signal (RS) that is also referred to as a pilot signal. The gNB transmits data information or DCI through the corresponding physical DL shared channel (PDSCH) or physical DL control channel (PDCCH). The PDSCH or PDCCH can be transmitted through a variable number of time slot symbols including one time slot symbol. For simplicity, the DCI format for scheduling the PDSCH reception by the UE is called the DL DCI format, and the DCI format for scheduling the PUSCH transmission from the UE is called the UL DCI format.

[0064] The gNB transmits one or more of multiple types of reference signals (RS) including channel state information RS (CSI-RS) and demodulation RS (DMRS). The CSI-RS is mainly intended for the UE to perform measurements and provide channel state information (CSI) to the gNB. For channel measurements, non-zero power CSI-RS (NZP CSI-RS) resources are used. For interference measurement reports (IMR), CSI interference measurement (CSI-IM) resources associated with zero power CSI-RS (ZP CSI-RS) configurations are used. The CSI process consists of NZP CSI-RS and CSI-IM resources.

[0065] The UE can determine CSI-RS transmission parameters through DL control signaling from the gNB or higher layer signaling such as radio resource control (RRC) signaling. The transmission instance of CSI-RS can be indicated by DL control signaling or configured by higher layer signaling. The DMRS is only transmitted within the BW of the corresponding PDCCH or PDSCH, and the UE can use the DMRS to demodulate data or control information.

[0066] Figure 4 and Figure 5 FIG. shows an example wireless transmit and receive path according to the present disclosure. In the following description, the transmit path 400 may be described as being implemented in a gNB (such as, gNB 102), while the receive path 500 may be described as being implemented in a UE (such as, UE 116). However, it can be understood that the receive path 500 may be implemented in the gNB, and the transmit path 400 may be implemented in the UE. In some embodiments, the receive path 500 is configured to support codebook designs and structures for systems with 2D antenna arrays, as described in the embodiments of the present disclosure.

[0067] As Figure 4 shown, the transmit path 400 includes a channel coding and modulation block 405, a serial-to-parallel (S-to-P) block 410, an inverse fast Fourier transform (IFFT) block 415 of size N, a parallel-to-serial (P-to-S) block 420, a cyclic prefix addition block 425, and an up-conversion converter (UC) 430. As Figure 5 shown, the receive path 500 includes a down-conversion converter (DC) 555, a cyclic prefix removal block 560, a serial-to-parallel (S-to-P) block 565, a fast Fourier transform (FFT) block 570 of size N, a parallel-to-serial (P-to-S) block 575, and a channel decoding and demodulation block 580.

[0068] As Figure 4As shown in [Figure 0], the channel coding and modulation block 405 receives a set of information bits, applies coding (such as, low-density parity-check (LDPC) coding), and modulates the input bits (such as, with quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)) to generate a sequence of frequency-domain modulation symbols.

[0069] The serial-to-parallel block 410 converts (such as, demultiplexes) the serial modulated symbols into parallel data to generate N parallel symbol streams, where N is the IFFT / FFT size used in gNB 102 and UE 116. The size-N IFFT block 415 performs an IFFT operation on the N parallel symbol streams to generate a time-domain output signal. The parallel-to-serial block 420 converts (such as, multiplexes) the parallel time-domain output symbols from the size-N IFFT block 415 to generate a serial time-domain signal. The cyclic prefix addition block 425 inserts a cyclic prefix into the time-domain signal. The upconverter 430 modulates (such as, upconverts) the output of the cyclic prefix addition block 425 to an RF frequency for transmission via the wireless channel. The signal can also be filtered at baseband before conversion to the RF frequency.

[0070] The RF signal transmitted from gNB 102 reaches UE 116 after passing through the wireless channel, and operations opposite to those at gNB 102 are performed at UE 116.

[0071] As Figure 5 shown in [Figure 11], the downconverter 555 downconverts the received signal to a baseband frequency, and the cyclic prefix removal block 560 removes the cyclic prefix to generate a serial time-domain baseband signal. The serial-to-parallel block 565 converts the time-domain baseband signal into a parallel time-domain signal. The size-N FFT block 570 performs an FFT algorithm to generate N parallel frequency-domain signals. The parallel-to-serial block 575 converts the parallel frequency-domain signals into a sequence of modulated data symbols. The channel decoding and demodulation block 580 demodulates and decodes the modulated symbols to recover the original input data stream.

[0072] Each of gNBs 101 to 103 can implement a transmit path 400 similar to that shown in [Figure 14] for transmitting to UEs 111 to 116 in the downlink, and can implement a receive path 500 similar to that shown in [Figure 16] for receiving from UEs 111 to 116 in the uplink. Similarly, each of UEs 111 to 116 can implement a transmit path 400 for transmitting to gNBs 101 to 103 in the uplink, and can implement a receive path 500 for receiving from gNBs 101 to 103 in the downlink. Figure 4 Figure 5

[0073] It can be implemented using only hardware or using a combination of hardware and software / firmware.​​Figure 4 and Figure 5 each of the components in. As a specific example, Figure 4 and Figure 5 at least some of the components in can be implemented in software, while other components can be implemented by configurable hardware or a mixture of software and configurable hardware. For example, the FFT block 570 and the IFFT block 515 can be implemented as configurable software algorithms, where the value of the size N can be modified according to the implementation.

[0074] In addition, although described as using FFT and IFFT, this is only by way of illustration and should not be construed as limiting the scope of the present disclosure. Other types of transforms can be used, such as discrete Fourier transform (DFT) and inverse discrete Fourier transform (IDFT) functions. It can be understood that the value of the variable N can be any integer for DFT and IDFT functions (such as, 1, 2, 3, 4, etc.), while the value of the variable N can be any integer that is a power of two for FFT and IFFT functions (such as, 1, 2, 4, 8, 16, etc.).

[0075] Although Figure 4 and Figure 5 show examples of wireless transmit and receive paths, various changes can be made to Figure 4 and Figure 5 . For example, Figure 4 and Figure 5 the various components in can be combined, further subdivided, or omitted, and additional components can be added according to specific requirements. Additionally, Figure 4 and Figure 5 are intended to show examples of the types of transmit and receive paths that can be used in a wireless network. Any other suitable architecture can be used to support wireless communication in a wireless network.

[0076] The hybrid time slot includes a DL transmission region, a guard period region, and a UL transmission region, similar to the special subframe in the NR specification. For example, the DL transmission region can include PDCCH and PDSCH transmissions, and the UL transmission region can include PUCCH transmissions. For example, the DL transmission region can include PDCCH transmissions, and the UL transmission region can include PUSCH and PUCCH transmissions.

[0077] The UL signal also includes a data signal for transmitting information content, a control signal for transmitting a UL control signal (UCI), a DMRS associated with data or UCI demodulation, a sounding reference signal (SRS) that enables the gNB to perform UL channel measurements, and a random access (RA) preamble that enables the UE to perform random access (also see the NR specification). The UE transmits data information or UCI through the corresponding physical UL shared channel (PUSCH) or physical UL control channel (PUCCH). The PUSCH or PUCCH can be transmitted through a variable number of time slot symbols including one time slot symbol. The gNB can configure the UE to transmit signals on the cell within the UL BWP of the cell UL BW.

[0078] The UCI includes hybrid automatic repeat request acknowledgment (HARQ-ACK) information indicating correct or incorrect detection of a transport block (TB) in the PDSCH, a scheduling request (SR) indicating whether there is data in the buffer of the UE, and a CSI report that enables the gNB to select appropriate parameters for PDSCH or PDCCH transmission to the UE. The HARQ-ACK information can be configured to have a finer granularity than per TB, and can be per data code block (CB) or per data CB group, where a TB includes multiple data CBs.

[0079] The CSI report from the UE can include a channel quality indicator (CQI) that notifies the gNB of the maximum modulation and coding scheme (MCS) that enables the UE to detect a data TB with a predetermined block error rate (BLER) (such as 10% BLER (see the NR specification)), a precoding matrix indicator (PMI) indicating how the gNB combines signals from multiple transmitter antennas according to the multiple input multiple output (MIMO) transmission principle, and a rank indicator (RI) indicating the transmission rank of the PDSCH.

[0080] The UL RS includes DMRS and SRS. The DMRS is only transmitted within the BW of the corresponding PUSCH or PUCCH transmission. The gNB can use the DMRS to demodulate the information in the corresponding PUSCH or PUCCH. The SRS is transmitted by the UE to provide UL CSI to the gNB, and for a TDD system, the SRS transmission can also provide a PMI for DL transmission. Additionally, to establish synchronization or an initial higher layer connection with the gNB, the UE can transmit a physical random access channel (PRACH, as shown in the NR specification).

[0081] Many frequency bands are flexible TDD frequency bands, where the reception by the UE (or transmission from the gNB) and the transmission from the UE (or reception by the gNB) are based on Time Division Duplex (TDD). For example, most of the frequency bands for 5G / NR are TDD frequency bands. TDD operation offers some important advantages, such as using the same frequency band for DL and UL transmissions, which results in a simpler UE implementation, for example because a duplexer is not required, and the ability to utilize the channel reciprocity between DL and UL to provide accurate link adaptation. However, TDD operation also has some important disadvantages, such as increased latency (because transmission / reception in a link direction (UL or DL) may not be possible at all times), reduced data rate, and reduced coverage at a given latency compared to Frequency Division Duplex (FDD).

[0082] To address some of the disadvantages of TDD operation, dynamic adaptation of the link direction has been considered, where, except for some symbols in some time slots that support a predetermined transmission (such as for SS / PBCH blocks), the symbols of a time slot can have a flexible direction (UL or DL), and the UE can determine the above direction based on the scheduling information for reception or transmission. The control channel can also be used to provide a DCI format that can indicate the link direction of some flexible symbols in one or more time slots, such as DCI format 2_0 in the NR specification. However, in actual deployment, it is difficult for the gNB scheduler to adapt the transmission direction of symbols without coordinating with other gNB schedulers in the network. This is because of cross-link interference (CLI), where, for example, UL transmissions on a cell can experience significant interference from DL transmissions on an adjacent cell of the gNB.

[0083] Define antenna ports such that the channel for transmitting one symbol on an antenna port can be inferred from the channel for transmitting another symbol on the same antenna port.

[0084] For the DM-RS associated with the PDSCH, the channel for transmitting the PDSCH symbol on an antenna port can be inferred from the channel for transmitting the DM-RS symbol on the same antenna port only if the two symbols are within the same resource, in the same time slot, and in the same PRG as the scheduled PDSCH.

[0085] For the DM-RS associated with the PDCCH, the channel for transmitting the PDCCH symbol on an antenna port can be inferred from the channel for transmitting the DM-RS symbol on the same antenna port only if the two symbols are within a resource for which the UE can assume the same precoding.

[0086] For the DM-RS associated with PBCH, the channel for transmitting PBCH symbols on the same antenna port can be inferred from the channel for transmitting DM-RS symbols on the same antenna port only if the two symbols are within the SS / PBCH block transmitted in the same time slot and have the same block index.

[0087] If the large-scale properties of the channel for transmitting symbols on one antenna port can be inferred from the channel for transmitting symbols on another antenna port, the two antenna ports are considered to be quasi-co-located. The large-scale properties include one or more of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial Rx parameters.

[0088] The UE may assume that SS / PBCH blocks transmitted with the same block index at the same center frequency position are quasi-co-located in terms of Doppler spread, Doppler shift, average gain, average delay, delay spread, and spatial Rx parameters (when applicable). For any other SS / PBCH block transmission, the UE may not assume quasi-co-location.

[0089] In the absence of CSI-RS configuration and unless otherwise configured, the UE may assume that the PDSCH DM-RS and SS / PBCH blocks are quasi-co-located in terms of Doppler shift, Doppler spread, average delay, delay spread, and spatial Rx parameters (when applicable). The UE may assume that the PDSCH DM-RS within the same CDM group is quasi-co-located in terms of Doppler shift, Doppler spread, average delay, delay spread, and spatial Rx. The UE may also assume that the DMRS ports associated with the PDSCH are QCL type A, type D (when applicable), and average gain QCL. The UE may further assume that the DM-RS does not conflict with the SS / PBCH block.

[0090] The UE may be configured with a list of up to M TCI-State configurations within the higher layer parameter PDSCH-Config to decode the PDSCH according to the detected PDCCH with DCI intended for the UE and a given serving cell, where M depends on the UE capability maxNumberConfiguredTCIstatesPerCC. Each TCI-State contains parameters for configuring the quasi-co-location (QCL) relationship between one or two downlink reference signals and the DMRS ports of the PDSCH, the DMRS ports of the PDCCH, or the CSI-RS ports of the CSI-RS resources.

[0091] The quasi - co - location relationship is configured by the higher - layer parameter qcl - Type1 for the first DL RS and qcl - Type2 (if configured) for the second DL RS. For the case of two DL RSs, the QCL types can be different regardless of whether they refer to the same or different DL RSs. The quasi - co - location type corresponding to each DL RS is given by the higher - layer parameter qcl - Type in QCL - Info and can take one of the following values: QCL - TypeA: {Doppler shift, Doppler spread, mean delay, delay spread}; QCL - TypeB: {Doppler shift, Doppler spread}; QCL - TypeC: {Doppler shift, mean delay}; and QCL - TypeD: {spatial Rx parameter}.

[0092] The UE receives a MAC - CE activation command for mapping up to [N] (e.g., N = 8) TCI states to the code points of the DCI field "transmission configuration indication". When transmitting the HARQ - ACK for the PDSCH carrying the activation command in slot n, the mapping indicated between the TCI state and the code points of the DCI field "transmission configuration indication" can be applied after the MAC - CE application time, e.g., starting from the first slot after the slot in question.

[0093] The random access (RA) process can be initiated by the following methods: RRC (for SI request) - if SIB1 includes scheduling information for (on - demand) SI request; MAC; and PDCCH - command.

[0094] The random access process can be initiated for at least one of the following triggers / purposes: (1) initial access for establishing an RRC connection (from RRC_IDLE to RRC_CONNECTED); (2) re - establishing an RRC connection after radio link failure (RLF); (3) on - demand system information (SI) request; (4) handover; (5) UL synchronization; (6) scheduling request (SR); (7) positioning; and (8) link recovery - also known as beam failure recovery (BFR).

[0095] Random access (RA) can operate in two modes: (i) contention - based random access (CBRA), where UEs within a serving cell can share the same RA resources and thus there may be conflicts between RA attempts from different UEs; and (ii) contention - free random access (CFRA), where the UE has dedicated RA resources indicated by the serving gNB and cannot share them with other UEs, so that RA conflicts can be avoided. For example, CBRA can be used for all of the above triggers / purposes, while CFRA can be used only for the triggers / purposes (4) to (8) as shown above.

[0096] The 4-step random access procedure, also known as type-1 (L1) random access procedure, consists of the following steps / operations by the UE: transmitting a PRACH preamble (Msg1); attempting to receive a random access response (RAR or Msg2); transmitting a contention resolution message (Msg3); and attempting to receive a contention resolution message (Msg4).

[0097] Alternative random access procedures can also be considered, which are the so-called 2-step RACH or type-2 L1 random access procedures, where Msg1 and Msg3 are combined and transmitted as "MsgA", and the above Msg2 and Msg4 are combined and received as "MsgB".

[0098] Various embodiments of the present disclosure relate to 4-step RACH, but the embodiments can generally also be applied to 2-step RACH, and for the sake of brevity, explicit individual descriptions are usually omitted.

[0099] The PRACH preamble transmission (for both CBRA and CFRA modes) is associated with DL RS. This association can help the serving gNB identify the uplink spatial receive filter / beam for receiving the PRACH, and can also help the UE identify the uplink spatial transmit filter / beam for transmitting the PRACH. For example, the UE can use an uplink filter / beam that is the same as or related to (such as having the same quasi-co-location (QCL) properties and / or the same direction but a narrower width) the DL reception of the indicated DL RS for Msg1 transmission. This association can also be used in the NR specification to provide DLRS resources for path loss estimation, which is used to determine the PRACH preamble transmission power.

[0100] The DL RS for Msg1 transmission can be one of the following options based on the PRACH scenario: SSB: for BFR, CFRA, PDCCH-command PRACH, SI request, CBRA; or CSI-RS: for BFR, CFRA, CBRA.

[0101] Throughout the present disclosure, SSB is used as a short form of the SS / PBCH block. The terms SSB and SS / PBCH block are used interchangeably in the present disclosure.

[0102] In addition, the serving cell may be configured with both SSB and CSI-RS for PRACH transmission. For example, some PRACH preambles may be associated with SSB for QCL determination, and some PRACH preambles may be associated with CSI-RS for QCL determination. It is also possible that a secondary serving cell (SCell) does not have any SSB configuration / transmission, but only supports PRACH transmission from the UE that uses CSI-RS for QCL determination. Then, as described in the previous paragraph, it is not applicable to certain random access triggers / modes (such as for PDCCH-command PRACH or for SI requests).

[0103] The PRACH configuration includes RACH opportunities (ROs) that repeat periodically in certain RACH time slots and certain frequency resource blocks.

[0104] Once the UE has transmitted a PRACH preamble (Msg1), there are three more steps for a (4-step) PRACH to complete: the UE attempts to receive a random access response (RAR or Msg2) from the gNB; the UE transmits a contention resolution message (Msg3) to the gNB; and the UE attempts to receive a contention resolution response message (Msg4) from the gNB.

[0105] The random access response (RAR or Msg2) is a PDCCH / PDSCH transmission received by the UE on the DL BWP of the SpCell, as described below: on the initial DL BWP of the PCell / SpCell (for the case of initial access, i.e., establishing (re-establishing) an RRC connection); or on the active DL BWP of the SpCell (with the same BWP index as the active UL BWP) (for random access triggers other than initial access). If the active DL BWP index (of the SpCell) is not equal to the active UL BWP index (of the serving cell), then switch the active DL BWP to the one with the same BWP index.

[0106] The SCS of the PDCCH in the RAR message is the SCS for the Type1-PDCCH CSS set. The SCS for any future PDSCH is also the same as the SCS of the PDSCH in the RAR, unless the UE is configured with an SCS.

[0107] The PDCCH for the RAR is DCI format 1_0 that the UE monitors in the Type1-PDCCH common search space (CSS) set of the SpCell identified by the RA-RNTI (or in the search space indicated by the recoverySearchSpaceId of the SpCell identified by the C-RNTI for the case of BFR using CF-RA) during a certain configured time window.

[0108] The PDSCH part of the RAR contains the gNB response (note that the PDSCH can carry RAR messages for multiple UEs), and this gNB response can be one of the following three types.

[0109] In one example, the gNB sends a 4-bit backoff indicator (BI), which indicates the maximum backoff time required before the UE's next PRACH transmission attempt [the actual backoff time is randomly selected uniformly by the UE between zero and the value indicated by the BI field], and this response identifies the overload condition of the serving cell.

[0110] In another example, the gNB only sends a 6-bit random access preamble ID (RAPID), which indicates the ID of the preamble detected by the gNB, and this response is only applicable to the confirmation of SI requests.

[0111] In one example, the gNB sends the RAPID and a MAC payload (also known as MAC RAR), which includes a 12-bit timing advance (TA) command, a 27-bit uplink grant field for Msg3, and a 16-bit temporary C-RNTI (TC-RNTI).

[0112] Figure 6A An example E / R / R / BIMAC subheader 600 according to an embodiment of the present disclosure is shown. Figure 6A The embodiment of the E / R / R / BI MAC subheader 600 shown is for illustration only. Figure 6A One or more components shown therein can be implemented in a dedicated circuit configured to perform the functions, or one or more components can be implemented by one or more processors executing instructions to perform the functions. Other embodiments are used without departing from the scope of the present disclosure.

[0113] Figure 6B An example E / T / RAPID MAC subheader 650 according to an embodiment of the present disclosure is shown. Figure 6B The embodiment of the E / T / RAPID MAC subheader 650 shown is for illustration only. Figure 6B One or more components shown therein can be implemented in a dedicated circuit configured to perform the functions, or one or more components can be implemented by one or more processors executing instructions to perform the functions. Other embodiments are used without departing from the scope of the present disclosure.

[0114] Figure 6C An example MAC RAR 670 according to an embodiment of the present disclosure is shown. Figure 6C The embodiment of the MAC RAR 670 shown is for illustration only. Figure 6COne or more components shown in [the figure] may be implemented in a dedicated circuit configured to perform the function, or one or more components may be implemented by one or more processors executing instructions to perform the function. Other embodiments are used without departing from the scope of the present disclosure.

[0115] <Table 1, Random Access Response Grant Content Field Sizes>

[0116]

[0117]

[0118] Table 1 includes Random Access Response Grant Content Field Sizes, which includes similar tables for LTE and NR specifications.

[0119] For the case of CFRA-based BFR, it is sufficient for the RAR to be considered successful as long as the PDCCH is received during the time window and in the indicated search space of the SpCell and is correctly addressed to the C-RNTI.

[0120] For other cases (such as CBRA and SI requests), the RAR is successful if: (i) the PDCCH in the Type1-PDCCH common search space (CSS) set of the SpCell is received during the configured time window and the PDCCH is addressed to the RA-RNTI; and (ii) the corresponding PDSCH is correctly decoded [note that HARQ is not supported for RAR]; and (iii) the MAC RAR contained in the PDSCH part of the RAR contains the Random Access Preamble ID (RAPID); and (iv) the RAPID in the MAC RAR matches the preamble selected by the UE and transmitted in Msg1. Then, for the serving cell that transmits the PRACH preamble / Msg1, the UE applies the TA to adjust / correct the timing between the UE and the gNB, stores the TC-RNTI for future transmissions, and processes the RAR UL grant to transmit Msg3.

[0121] If the RAR is not successful, the UE attempts (possibly after a backoff and / or after up to N T，1 +0.75 msec of UE processing time as specified in the NR specification) to transmit a new PRACH preamble with PRACH resource selection (possibly including different SSBs and / or different preambles) and may apply PRACH preamble power ramping, unless the UE has reached the configured maximum number of PRACH attempts, in which case, the random access problem is reported to the higher layer and the procedure stops.

[0122] The following is only about frequency-domain resource allocation. Since LTE only supports PUSCH transmission based on subframes, time-domain resource allocation information is not required.

[0123] The (frequency) resource allocation for Msg3 in LTE (as identified in the RAR UL grant) includes: a 1-bit hopping flag; and a 10-bit resource block assignment.

[0124] According to the 10-bit resource assignment field, a b-bit field is generated as follows, where where is the system bandwidth in terms of the number of RBs (with a subcarrier spacing of 15 kHz). It should be noted that b is the total number of consecutive resource allocations of any length in a system with a bandwidth equal to PRBs.

[0125] If (such that b < 10), then truncate the 10-bit resource block assignment and use the least significant b bits next.

[0126] If (such that b ≥ 10), then after the N_{UL, hopping} = 0, 1, 2 most significant bits of the 10-bit resource assignment field, add zero-padding bits, where such that the entire field is b bits.

[0127] If the hopping flag is 0, then N_{UL, hopping} = 0 (i.e., disabled).

[0128] If the hopping flag is 1 and the system bandwidth is PRBs, then N_{UL, hopping} = 1.

[0129] If the hopping flag is 1 and the system bandwidth is PRBs, then N_{UL, hopping} = 2.

[0130] Finally, similar to LTE DCI format 0, the obtained b-bit field is decoded as follows.

[0131] In one example, since the resource allocation type bit does not exist in the RAR UL grant, only resource allocation type 0 is supported. In such an example, uplink resource allocation type 0 indicates a set of continuously allocated virtual resource blocks starting from the starting resource block (RB START ) and having a length (L CRBs ≥ 1) in terms of continuously allocated resource blocks. This indication is via the parameter "resource indication value" (RIV), and RIV combines RB START and L CRBs to generate a value associated with RB START and L CRBsValues that can be described with a smaller number of bits compared to the separate and individual indication of the required number of bits.

[0132] In another example, for PUSCH frequency hopping (resource allocation type 0 only): N UL_hop MSB bits are used to obtain the value as indicated in the LTE specification; and (b - N UL_hop ) bits provide the resource allocation for the first time slot in the UL subframe.

[0133] In yet another example, for non - frequency - hopping PUSCH with resource allocation type 0: b bits provide the resource allocation in the UL subframe as defined in the LTE specification.

[0134] The following is only regarding frequency - domain resource allocation, since LTE MTC only supports PUSCH transmission based on subframes and thus does not require time - domain resource allocation information.

[0135] The resource allocation for Msg3 in LTE MTC CEmodeA (as identified in the RAR UL grant) includes: bits for the narrowband index of the Msg3 PUSCH (assuming a maximum system bandwidth of 100 PRBs = 20 MHz) together with zero - padding bits (to keep the size of the RAR UL grant fixed), and 4 bits for the resource allocation within the narrowband, where and and is the total UL system bandwidth.

[0136] Interpret the resource allocation field (for LTE MTC CEmodeA) as follows: Insert a most - significant bit with a value set to "0", and interpret the extended resource allocation using the indicated UL resource allocation type 0 within the narrowband. It should be noted that in general, the indication of all possible consecutive resource allocations within a 6 - PRB narrowband requires 5 bits (such is the case for DCI format 6 - 0A), however, only 4 bits are used and by concatenating the "0" MSB, consecutive resource allocations of length 1, 2, 3, and 6 PRBs within the narrowband can be indicated (i.e., the RAR UL cannot indicate a PUSCH Msg3 of length 4 or 5 PRBs). Note that there is no 1 - bit frequency - hopping flag for PUSCH Msg3 in the RAR UL grant.

[0137] The RAR UL grant also includes a 2 - bit field for the number of repetitions of the Msg3 PUSCH, such that the repetition level (N Msg3 ) of the initial transmission of the Msg3 PUSCH is based on Table 2 (as shown in the LTE specification), where if Y is signaledA , then Y A is determined by the higher layer parameter pusch-maxNumRepetitionCEmodeA-r13, otherwise Y A = 8.

[0138] <Table 2. Msg3 PUSCH repetition level values for CEmodeA>

[0139] Value of "repetition times" Msg3 PUSCH repetition level "00” <![CDATA[Y A / 8]]> "01” <![CDATA[Y A / 4]]> "10” <![CDATA[Y A / 2]]> "11” <![CDATA[Y A >

[0140] The resource allocation for Msg3 in the NR specification (as identified in the RAR UL grant) includes: a 1-bit hopping flag; a 4-bit PUSCH time resource allocation; and a 14-bit PUSCH frequency resource allocation.

[0141] The 4-bit field for time resource allocation can be used according to the NR specification to identify the start symbol and the time domain length of the Msg3 PUSCH transmission.

[0142] The 14-bit field for frequency resource allocation is performed by the uplink resource allocation type 1 according to the NR specification, which identifies the allocation of consecutive (virtual) resource blocks, similar to the above LTE resource allocation type 0.

[0143] According to the 14-bit resource assignment field, a b-bit field is generated as follows, where where is the bandwidth of the initial UL BWP in terms of the number of RBs (at the subcarrier spacing of the initial UL BWP), regardless of whether the active UL BWP for PUSCHMsg3 is the initial UL BWP or another UL BWP with the same / different subcarrier spacing. It should be noted that b is the total number of consecutive resource allocations of any length in the BWP equal to PRBs.

[0144] If (such that b < 14), then truncate the 14-bit frequency resource allocation and then use the least significant b bits.

[0145] If (such that b ≥ 14), then after the N_{UL, hopping} = 0, 1, 2 most significant bits of the 10-bit resource assignment field, add zero padding bits, where such that the whole field is b bits.

[0146] If the hopping flag is 0, then N_{UL, hopping} = 0 (i.e., disabled).

[0147] If the hopping flag is 1 and the system bandwidth is For N PRBs, N_{UL, frequency hopping} = 1 (which also conforms to the 2 offset values configured in the higher layer parameter frequencyHoppingOffsetLists).

[0148] If the frequency hopping flag is 1 and the system bandwidth is For N PRBs, N_{UL, frequency hopping} = 2 (which also conforms to the 4 offset values configured in the higher layer parameter frequencyHoppingOffsetLists).

[0149] Finally, as in NR DCI format 0_0, the obtained b-bit field is decoded as follows.

[0150] In one example, for DCI format 0_0 (and thus for PUSCH Msg3 in the NR specification), only resource UL allocation type 1 is supported.

[0151] In this example, uplink resource allocation type 1 indicates a set of continuously allocated virtual resource blocks starting from the starting resource block (RB START ) and having a length (L RBs ) for the continuously allocated resource blocks. This indication is via the parameter "resource indication value" (RIV), and RIV combines RB START and L RBs to generate a value that can be described with fewer bits compared to the number of bits required for separate and individual indication of RB START and L RBs .

[0152] In this example, it should be noted that in DCI format 0_0, the size of the bit field for frequency resource allocation type 1 conforms to the size of the UL BWP. However, the RAR UL grant considers a fixed-size field of 14 bits.

[0153] In another example, for PUSCH frequency hopping using resource allocation type 1: N UL_hop MSB bits are used to obtain the frequency hopping parameters as indicated in the NR specification; and (b - N UL_hop ) bits provide the resource allocation for the first time slot in the UL subframe.

[0154] In yet another example, for non-frequency-hopping PUSCH using resource allocation type 1: b bits provide the resource allocation in the UL subframe as defined in the NR specification.

[0155] In the present disclosure, the terms "4-step RACH" and "type-1 random access procedure" and "type-1 L1 random access procedure" may be used interchangeably. Throughout the present disclosure, the terms "2-step RACH" and "type-2 random access procedure" and "type-2 L1 random access procedure" may be used interchangeably.

[0156] Before starting the physical random access procedure, layer 1 receives an indication from a higher layer to perform a type-1 random access procedure (4-step RACH) or a type-2 random access procedure (2-step RACH).

[0157] From the perspective of the physical layer, the type-2 L1 random access procedure includes transmitting a random access preamble in the PRACH and transmitting the PUSCH (MsgA) and receiving the RAR message (MsgB) with PDCCH / PDSCH. When the random access response of the 2-step RACH indicates a fallback to the 4-step RACH (i.e., fallbackRAR), the 2-step RACH procedure continues similar to the 4-step RACH procedure, i.e., transmitting the PUSCH scheduled by the RAR UL grant and transmitting the PDSCH for contention resolution.

[0158] The PRACH preambles for the 2-step RACH are separate from those for the 4-step RACH. For example, the contention-based preamble R for each SS / PBCH block of each valid PRACH occasion for the type-2 random access procedure starts after the preambles for the type-1 random access procedure.

[0159] The RACH opportunities (ROs) for the 2-step RACH and those for the 4-step RACH can be common / shared or can be separate.

[0160] In response to the transmission of the PRACH and PUSCH, the UE attempts to detect DCI format 1_0 with a CRC scrambled by RA-RNTI / MsgB-RNTI during a window controlled by a higher layer, as shown in the NR specification.

[0161] As defined in the NR specification, the window starts at the first symbol of the earliest CORESET where the UE is configured to receive the PDCCH for the Type1-PDCCH CSS set. The window is at least one symbol after the last symbol of the PUSCH occasion corresponding to the PUSCH transmission (associated with the 2-step RACH), where the symbol duration corresponds to the SCS of the type1-PDCCH CSS set. Based on the SCS of the type1-PDCCH CSS set, the length of the window in terms of the number of slots is provided by ra-ResponseWindow (as for the 4-step RACH) or a separately configured time window length for the 2-step RACH.

[0162] If the UE detects DCI format 1_0 with a CRC scrambled by RA-RNTI / MsgB-RNTI and the transport block in the corresponding PDSCH within the window, the UE passes the transport block to the higher layer.

[0163] The higher layer indicates to the physical layer that if the RAR message is for fallbackRAR and the random access preamble identifier (RAPID) associated with the PRACH transmission is recognized, an uplink grant is indicated, and when the UE detects the RAR UL grant, the UE procedure continues as in the 4-step RACH procedure; or if the RAR message is for successRAR, the transmission of PUCCH is indicated, and the PUCCH has HARQ-ACK information with an ACK value.

[0164] In this case, the PUCCH resource for the PUCCH transmission is indicated by the 4-bit PUCCH resource indicator field in the successRAR from the PUCCH resource set provided by pucch-ResourceCommon; the time slot for the PUCCH transmission is indicated by the 3-bit PDSCH-to-HARQ feedback timing indicator field in the successRAR with a value k from {1, 2, 3, 4, 5, 6, 7, 8}, and referring to the time slot for the PUCCH transmission with a duration T slot The time slot is determined as ceil(n + k + Δ + t Δ / T slot ), where n is the time slot of the PDSCH reception, Δ is defined, for example, as for the PUSCH transmission (as shown in the NR specification) or according to different tables provided in the system specification, and t Δ ≥0; the first symbol of the PUCCH transmission that the UE does not expect is within less than N T,1 +0.5 + t Δ msec after the last symbol of the PDSCH reception, where N T,1 is the PDSCH processing time for UE processing capability 1 as defined in the NR specification; and / or the PUCCH transmission has the same spatial domain transmission filter as the last PUSCH transmission and is in the same active UL BWP.

[0165] If the UE detects DCI format 1_0 with a CRC scrambled by the C-RNTI and the transport block in the corresponding PDSCH within the window, the UE transmits the PUCCH, where the HARQ-ACK information has an ACK value if the UE correctly detects the transport block, or a NACK value if the UE incorrectly detects the transport block and the timing alignment timer is running.

[0166] The UE does not expect to be indicated to transmit the PUCCH with HARQ-ACK information at a time before the time when the UE applies the TA command provided by the transport block.

[0167] If the UE does not detect DCI format 1_0 with CRC scrambled by the corresponding RA-RNTI / MsgB-RNTI within the window, or if the UE does not correctly receive the transport block in the corresponding PDSCH within the window, or if the higher layer does not recognize the RAPID associated with the PRACH transmission from the UE, the higher layer may instruct the physical layer to transmit only the PRACH according to the type-1 random access procedure or to transmit both the PRACH and the PUSCH according to the type-2 random access procedure.

[0168] If requested by the higher layer, it is expected that the UE transmits the PRACH no later than N T,1 +0.75 msec after the last symbol of the window or the last symbol of the PDSCH reception, where N T,1 is the duration of N1 symbols of the PDSCH processing time corresponding to the UE processing capability 1. For μ = 0, the UE assumes N 1,0 = 14 (as shown in the NR specification).

[0169] Unless the UE is configured with an SCS, the UE uses the same SCS as the PDSCH reception that provided the RAR message to receive subsequent PDSCHs.

[0170] For the case of contention-free random access (CF-RA) (and SI request), the correct reception of Msg2 / RAR is the last step of the random access procedure. However, for the case of contention-based random access (CB-RA), multiple UEs may have used the same preamble and more steps are required to resolve the contention. For the case of random access before the RRC_CONNECTED state (i.e., for initial access), the UE and the gNB need to exchange more information to set up the connection.

[0171] Therefore, the contention resolution request and possibly also the connection setup request require uplink PUSCH transmission (Msg3), and the contention resolution response and possibly also the connection setup response require downlink transmission (Msg4). If the UE receives Msg4 within a specific time window after the transmission of Msg3, the contention resolution (and connection setup, if applicable) is considered successful, and for the case where the UE does not yet have a C-RNTI, it is also successful if the contention resolution ID in Msg4 matches the ID transmitted by the UE in Msg3.

[0172] Otherwise, the contention resolution Msg3 / 4 and thus the RACH attempt are considered unsuccessful, and the UE needs to make another RACH attempt, unless the configured maximum number of RACH attempts has been exhausted, in which case the entire random access procedure is declared unsuccessful.

[0173] After a RACH attempt fails (due to no RAR reception, the RAP-ID in the RAR not matching that in Msg1, or failure in contention resolution of Msg3 / 4), the UE may re-perform RACH resource selection, including selecting the DL RS for the PRACH, selecting the PRACH preamble, and selecting the RACH occasion. Therefore, different SSB / CSI-RS and / or different PRACH preambles and / or different RACH occasions may be used for the next PRACH attempt compared to the previous PRACH attempt. However, power ramping is applied only if the same DL RS is used in the next PRACH attempt compared to the previous PRACH attempt.

[0174] Hereinafter and throughout this disclosure, the terms "NR-Light UE", "reduced-capability UE" or "RedCap UE", and "BL / CE UE" may be used interchangeably to refer to a UE or a group of UEs having reduced cost and / or complexity and / or capabilities (such as reduced bandwidth, reduced number of Rx and / or Tx RF chains, reduced power amplifier class (or simply, reduced power level)) compared to a UE or a group / category of UEs such as defined by the NR specification. Additionally, although some embodiments may refer to NR-Light UEs or RedCap UEs having reduced capabilities, costs, and / or complexities compared to traditional UEs, any embodiment of this disclosure may also be implemented in any type of UE, including for example, UEs having the same, similar, or more capabilities compared to traditional UEs.

[0175] Such a UE or group of UEs may be considered a UE category (or multiple UE categories) that meets certain radio / service requirements similar to 3GPP LTE UE Cat-M1. Additionally, such a UE or group / group of categories may support features for coverage enhancement.

[0176] Examples of such NR-light UEs may include wearable devices, smartwatches, surveillance cameras, and other mid-range wireless sensors used in industrial, residential, health, or public safety. In some scenarios and deployments, there may be hundreds or thousands of NR-Light UEs in the RRC_CONNECTED state within a serving cell. Unless otherwise explicitly mentioned, in the remainder of this disclosure, the term "UE" is also used to refer to an NR-Light UE as an exemplary implementation, or generally, to any UE that aims / requires coverage restoration or coverage enhancement for PRACH and / or other UL / DL transmissions, such as any (category of) low-capability UE, such as a feature phone, etc.

[0177] Although various embodiments of the present disclosure discuss 3GPP 5G NR communication systems, the embodiments can generally be applied to UEs operating with other RATs and / or standards such as the next version / next generation of 3GPP, IEEE WiFi, etc.

[0178] Hereinafter, unless otherwise explicitly indicated, providing a parameter value by a higher layer includes providing the parameter value by a system information block (SIB) (such as SIB1), or by common RRC signaling, or by UE-specific RRC signaling.

[0179] Hereinafter, the association between DL RSs (such as SS / PBCH blocks (SSB) or CSI-RS) and PRACH preambles is with respect to quasi-co-location (QCL) properties or transmission configuration indicator (TCI) states as shown in the NR specification.

[0180] A key element for improving the detection / miss probability of PRACH transmissions from a UE at the serving gNB is to increase the SINR of PRACH reception at the gNB. One way to increase the SINR is to repeat the PRACH transmission in multiple opportunities to increase the probability of correct detection of the PRACH preamble by the gNB and / or reduce the probability of collisions among a large number of UEs.

[0181] Accordingly, if needed, operations / messages after PRACH preamble transmission, such as random access response (RAR) and possibly Msg3 / 4 for contention resolution, can be repeated to increase reliability / robustness and improve coverage. The improved coverage leads to faster (initial) access, connection setup, UL synchronization, etc.

[0182] When considering a random access process with repetition, several issues need to be addressed, including the following: the timing of these messages when repetition is configured for random access Msg2 / 3 / 4; the time / frequency resource allocation for Msg3 PUSCH as indicated in the RAR UL grant; and congestion control for a large number of UEs via the distribution of UEs over the spectrum.

[0183] The present disclosure addresses the above issues and provides additional design aspects for supporting a random access process in which associated messages are repeatedly transmitted, and provides solutions outlined in the next section and further detailed hereinafter.

[0184] The present disclosure contemplates methods for repetition of RAR and Msg3 / 4, where the following concepts are introduced: repetition of random access response (RAR) and Msg3 / 4 based on RSRP range / CE level / UE power class; new DCI format / RNTI of RAR PDCCH and new length of CORESET depending on RSRP range / CE level / UE power class; timing of RAR reception with repetition - including start point of RAR PDCCH monitoring and length of monitoring window; timing of PRACH transmission after RAR failure when repeating RAR; timing of Msg3 PUSCH transmission / Msg4 PDSCH reception when repeating RAR and / or Msg3 / 4; modification of RAR UL grant - new fields such as number of repetitions of Msg3 PUSCH, UL BWP index of Msg3 PUSCH, DL BWP index of Msg3 / 4 PDCCH, modified fields such as fewer bits / no bits for Msg3 hopping, time / frequency allocation, MCS or TPC command; using UL BWP index of Msg3 PUSCH in RAR UL grant to distribute UEs in different parts of the spectrum and achieve congestion control; using DL BWP index of Msg3 / 4 PDCCH in RAR UL grant to distribute UEs in different parts of the spectrum and achieve congestion control; using UL resource allocation type 2 (i.e., RBG-level indication) for Msg3 PUSCH; and / or avoiding minimum K2 value of Msg3 PUSCH; and / or using "cellBarred" and "intraFreqReselection" fields in MIB during initial access to distribute UEs (such as NR-Light or low-capability UEs) across the spectrum.

[0185] In one embodiment, each of PDCCH and PDSCH transmissions associated with scheduling and transmission of random access response (RAR) may have respective N repetitions, where the value of N (the value of N may be the same or different for PDCCH and PDSCH) may be fixed in the specification or provided by a higher layer (from a specified list of repetition numbers). The motivation is to improve / recover / enhance DL coverage of the UE for the random access procedure. The embodiment may be applied before and / or after the UE operates in RRC connected mode and / or is provided with UE-specific configuration.

[0186] In one example, for all RSRP ranges, CE levels, and / or all UE power levels, the number of repetitions of the PDSCH transmission for providing the RAR can be the same. In another example, for different RSRP ranges, CE levels, and / or different UE power levels, the number can be different. For example, the power amplifier level (or simply, power level) of a UE (such as a RedCap / NR-Light Ue) can be a power amplifier level that is reduced compared to a reference power amplifier level (or simply, reference power level) such as 23 dBm, such as one of 10 dBm, 14 dBm, 17 dBm, 20 dBm.

[0187] In a related example, for all different CE levels and / or different UE power levels, the number of repetitions of the PDSCH transmission for providing the RAR is provided by a higher layer, such as value N0 for RSRP range 0 / CE level 0, value N1 for RSRP range / CE level 1, etc.

[0188] In another example, the number of repetitions of the PDSCH transmission for providing the RAR is configured only for a reference RSRP range / CE level and / or UE power level, and the number for another RSRP range / CE level and / or UE power level is determined based on a certain predefined rule, such as N1 for RSRP range / CE level 1 being twice as large as N0 for RSRP range / CE level 0.

[0189] In one example, the number of repetitions of the PDSCH transmission for providing the RAR can be different from the number of repetitions of the PDCCH scheduling the PDSCH transmission, and each number can be provided by the higher layer separately for each RSRP range / UE power level, or one number (such as the number of repetitions of the PDSCH transmission) can be derived from another number (such as the number of repetitions of the PDCCH transmission) provided by the higher layer.

[0190] Figure 7 An example determination 700 of the number of repetitions of the PDSCH transmission for providing the RAR based on RSRP range / CE level and UE power level according to an embodiment of the present disclosure is shown. Figure 7 The embodiment of the determination 700 of the number of repetitions shown is for illustration only. Figure 7 One or more of the components shown can be implemented in a dedicated circuit configured to perform the function, or one or more components can be implemented by one or more processors executing instructions to perform the function. Other embodiments are used without departing from the scope of the present disclosure.

[0191] In step 710, the UE selects a DL RS resource associated with PRACH transmission, such as an SSB or CSI-RS. In step 720, the UE then measures the RSRP of the selected DL RS resource, and in step 730, adjusts the measured RSRP value based on the UE power level, for example, based on the difference between the UE amplifier power level (or simply, the UE power level) (such as 10, 14, 17, 20 dBm) and the reference UE power amplifier level (or simply, the reference UE power level) (such as 23 dBm). In step 740, the UE compares the adjusted RSRP with a first threshold provided by a higher layer.

[0192] When the adjusted RSRP is less than the first threshold, in step 750, the UE determines a first repetition number for PDSCH reception that provides the RAR. When the adjusted RSRP is not less than the first threshold, in step 760, the UE compares the adjusted RSRP with a second threshold provided by a higher layer. When the adjusted RSRP is less than the second threshold, in step 770, the UE determines a second repetition number for PDSCH reception that provides the RAR; otherwise, the UE continues the same process until, in step 780, the UE compares the adjusted RSRP with a last threshold provided by a higher layer.

[0193] When the adjusted RSRP is less than the last threshold, in step 790, the UE determines a second-to-last repetition number for PDSCH reception that provides the RAR. When the adjusted RSRP is not less than the last threshold, in step 795, the UE determines a last repetition number for PDSCH reception that provides the RAR.

[0194] In one embodiment, when the determined RSRP value is greater than the RSRP threshold, the UE may receive the RAR with a first repetition number, and when the determined RSRP value is less than the RSRP threshold, receive it with a second repetition number. Here, the first repetition number is less than the second repetition number.

[0195] In one embodiment, the UE may receive the RAR via PDCCH / PDSCH transmission, where the PDCCH provides a DCI format different from DCI format 1_0 used in the NR specification and may be similar to DCI format 1_2 introduced in the NR specification.

[0196] In one example, the CRC for the DCI format may be scrambled with a new RNTI different from the RA-RNTI, such as the L-RNTI or RC-RNTI.

[0197] In one embodiment, the number of symbols of the CORESET in which the UE monitors the PDCCH for scheduling the PDSCH reception providing the RAR depends on the RSRP range / CE level and / or the PRACH preamble repetition count and / or the repetition count of the PDSCH transmission providing the RAR.

[0198] In one example, the UE may monitor the PDCCH in a search space set associated with a CORESET having a number of symbols determined for the corresponding CE level or UE power class. For example, when the UE operates at a lower CE level (such as CE level 0) and a larger RSRP range, the UE may monitor the PDCCH in a search space set associated with a CORESET having a length of {1, 2, 3} symbols, and when the UE operates at a higher CE level (such as CE level 1) and a lower RSRP range, it may monitor the PDCCH in a search space set associated with a CORESET having a length of {1, 2, 3, 6} symbols.

[0199] In one example, the search space set associated with the CORESET for monitoring the PDCCH (including the PDCCH scheduling the PDSCH transmission providing the RAR) may be based on a single / identical reference baseline CORESET#0 configured with a fixed maximum symbol length (such as 6 symbols) as specified in the system operation or provided by a higher layer, where the UE of each CE level or UE power class monitors the PDCCH in the search space set associated with the reference baseline CORESET#0 only within a certain number of symbols associated with the CE level or UE power class according to the mapping specified in the system operation or provided by a higher layer. For example, the UE at a lower CE level monitors the reference baseline CORESET#0 only within 2 out of 6 symbols. In these examples, all associated configurations may be provided by a higher layer (such as SIB1 and / or RRC).

[0200] In one example, the UE may be provided with multiple search space sets for monitoring the PDCCH.

[0201] In one example, the foregoing examples and / or embodiments may be applied to any PDCCH, regardless of whether it corresponds to the PDSCH providing the RAR.

[0202] In the foregoing examples and / or embodiments, the symbol duration corresponds to the SCS of the type1-PDCCH CSS set as defined in the NR specification.

[0203] Figure 8Shows an example determination by a UE of a CORESET length 800 for PDCCH monitoring based on an RSRP range / CE level and UE power class according to an embodiment of the present disclosure, where the PDCCH monitoring is associated with the scheduling of PDSCH reception that provides an RAR. Figure 8 The illustrated embodiment of the UE's determination of the CORESET length 800 is for illustrative purposes only. Figure 8 One or more of the components shown may be implemented in a dedicated circuit configured to perform the functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the functions. Other embodiments are used without departing from the scope of the present disclosure.

[0204] In step 810, the UE selects a DL RS resource associated with PRACH transmission, such as an SSB or CSI-RS, and in step 820, measures the RSRP of the selected DL RS resource. Next, in step 830, the measured RSRP value is adjusted based on the UE power class, such as based on the difference between the UE power amplifier class and a reference UE power amplifier class. In step 850, the UE compares the adjusted RSRP with a threshold that may be indicated by a higher layer. When the adjusted RSRP is less than the threshold, in step 850, the UE determines to monitor the PDCCH in a CORESET having a length of {1, 2, 3, 6} symbols for scheduling PDSCH reception that provides an RAR. When the adjusted RSRP is not less than the threshold, in step 860, the UE determines to monitor the PDCCH in a CORESET having a length of {1, 2, 3} symbols for scheduling PDSCH reception that provides an RAR.

[0205] In one embodiment, the start of a window for monitoring a PDCCH for scheduling a PDSCH that provides an RAR corresponding to a PRACH preamble transmission having more than one repetition may be determined according to the following options.

[0206] In an example (A) of the option, the window starts after the last PRACH preamble repetition and at the first symbol of the earliest CORESET, where the UE is configured to monitor the PDCCH for a Type1-PDCCH CSS set, and the Type1-PDCCH CSS set is located at least one symbol after the last symbol of the PRACH occasion corresponding to the last repetition of the PRACH transmission.

[0207] In another example (B) of the option, the window starts after the first PRACH preamble retransmission and at the first symbol of the earliest CORESET, where the UE is configured to monitor the PDCCH for the Type1-PDCCH CSS set, and the Type1-PDCCH CSS set is located at least one symbol after the last symbol of the PRACH occasion corresponding to the first repetition of the PRACH transmission.

[0208] In yet another example (C) of the option, the window starts after the transmission of the number of repetitions provided by the higher layer according to the total number of PRACH preamble repetitions. For example, the window starts after completing half of the total number of repetitions. The window starts at the first symbol of the earliest CORESET, where the UE is configured to monitor the PDCCH for the Type1-PDCCH CSS set, and the Type1-PDCCH CSS set is located at least one symbol after the last symbol of the PRACH occasion corresponding to the Nth repetition of the PRACH transmission, where N is fixed in the specification or provided by the higher layer. For all CE levels and / or UE power levels and / or UE bandwidth values / complexity levels / capabilities, the value of N can be the same, or it can be different for different CE levels and / or different UE power levels and / or different UE bandwidth values. In the latter case, the higher layer can provide the value of N separately for each CE level and / or UE power level and / or bandwidth value / complexity level / capability, or the higher layer can provide the value of N only for the reference setting, and the UE can determine the value of N for other settings based on the reference value and predetermined rules. For example, the value of N for RSRP range / CE level 1 is twice the value of N for RSRP range / CE level 0.

[0209] In the example, as defined in the NR specification, the symbol duration corresponds to the SCS of the type1-PDCCH CSS set.

[0210] The motivation for options (B) and (C) as shown above is that the gNB can detect the PRACH preamble before completing all PRACH preamble / Msg1 repetitions. Then, the gNB can transmit the PDSCH with the RAR earlier.

[0211] In one example, the UE can transmit the PRACH preamble and monitor the PDCCH on a different serving cell for scheduling the reception of the PDSCH providing the RAR.

[0212] In another example, the timing relationship / PDCCH monitoring gap between each repetition of the PRACH preamble transmission and the PDCCH monitoring occasion for scheduling the PDSCH providing the RAR can be defined.

[0213] In yet another example, the PRACH preamble transmission and PDCCH monitoring occasions may overlap. In other examples, different options may be used for different UE capabilities and / or operating frequency bands. For example, option (A) may be applied to a half-duplex UE, while option (A) or (B) or (C) may be applied to a full-duplex UE or to a UE operating in a TDD band or in an FDD band with a reference TDD UL / DL configuration.

[0214] In one example, for option (B) or (C), when the UE detects the DCI format for scheduling the PDSCH reception providing the RAR, the UE may indicate to the gNB to stop transmitting the remaining repetitions of the PDCCH / PDSCH for providing the RAR.

[0215] In another example, the indication may be implicit, e.g., by transmitting a HARQ ACK in the PUCCH such that when the gNB receives the PUCCH with the HARQ-ACK in response to the repetition of the PDCCH / PDSCH for providing the RAR, the gNB stops transmitting the remaining repetitions of the PDCCH / PDSCH for providing the RAR.

[0216] In one embodiment, for a UE configured with PRACH repeated transmission, the window size (configured by the higher layer parameter ra-ResponseWindow) for monitoring the PDCCH for scheduling the PDSCH reception having the RAR, in terms of the number of time slots, depends on the RSRP range / CE level and / or the starting symbol of the CORESET for PDCCH monitoring and / or the number of repetitions of the PRACH preamble transmission and / or the number of repetitions of the PDSCH reception providing the RAR. In one example, different window lengths are configured for different RSRP ranges / CE levels, or the same window length is configured for different numbers of repetitions of the PRACH transmission.

[0217] For example, a larger window size may be configured for a higher RSRP range / CE level and / or a larger number of repetitions of the PRACH transmission and / or a larger number of repetitions of the PDSCH reception providing the RAR. In another example, the window size may extend to include all repetitions of the PDSCH reception providing the RAR, e.g., as described in the foregoing embodiment.

[0218] In another example, the window length can be different, depending on the start symbol of the PDCCH monitoring occasion, as described in the foregoing embodiments. For example, the window size indicates the number of time slots after the last repetition of the PRACH preamble transmission, such that if the PDCCH monitoring starts after the first repetition of the PRACH preamble transmission (option (B) in the foregoing embodiments) or after a later repetition of the PRACH preamble transmission as defined in the specification of the system operation or indicated by a higher layer (option (C) in the foregoing embodiments), the actual length of the PDCCH monitoring window is the indicated window size value plus the number of time slots between the start symbol of the PDCCH monitoring occasion and the last repetition of the PRACH preamble transmission.

[0219] In one example, the window size provided by a higher layer indicates the actual window size and captures the effect of the start symbol of the PDCCH monitoring (as described in the foregoing embodiments).

[0220] In yet another example, the value provided by a higher layer for the window size is the actual window size, but the indication and / or actual length of the window for monitoring the PDCCH for scheduling the PDSCH reception providing the RAR is independent of the start symbol of the corresponding PDCCH monitoring occasion (that is, independent of all options in the foregoing embodiments), such that a sliding window can be applied for monitoring the PDCCH for scheduling the PDSCH reception providing the RAR.

[0221] In an example, as defined in the NR specification, the size of the window is in terms of the number of time slots determined by the SCS of the Type1-PDCCH CSS set.

[0222] Figure 9 An example determination 900 of the start symbol and length of the PDCCH monitoring window for scheduling the PDSCH reception providing the RAR in the case of a repeated PRACH preamble transmission according to an embodiment of the present disclosure is shown. Figure 9 The embodiment of the determination 900 of the start symbol and length shown is for illustration only. Figure 9 One or more of the components shown can be implemented in a dedicated circuit configured to perform the functions, or one or more of the components can be implemented by one or more processors executing instructions to perform the functions. Other embodiments are used without departing from the scope of the present disclosure.

[0223] Figure 9 A determination of the start symbol and length of the PDCCH monitoring window for scheduling the PDSCH reception providing the RAR in the case of a repeated PRACH preamble transmission is shown Figure 9 (4 repetitions are shown).

[0224] The upper diagram shows an example where the PDCCH monitoring window starts after the last repetition of the PRACH preamble transmission. The middle diagram shows an example where the PDCCH monitoring window starts after the first repetition of the PRACH preamble transmission. Thus, the window length extends based on the remaining number of repetitions of the PRACH preamble transmission (3 repetitions). The lower diagram shows an example where the PDCCH monitoring window starts after half of the repetitions of the PRACH preamble transmission have been completed (in this example diagram, 2 repetitions). Thus, the window length extends based on the remaining number of repetitions of the PRACH preamble transmission (in this example diagram, 2 repetitions).

[0225] Figure 10 Another example determination 1000 of the start symbol and length of the PDCCH monitoring window for scheduling PDSCH reception providing RAR in the case of repeated PRACH preamble transmission according to an embodiment of the present disclosure is shown. Figure 10 The embodiment of the determination 1000 of the start symbol and length shown is for illustration only. Figure 10 One or more of the components shown may be implemented in a dedicated circuit configured to perform the functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the functions. Other embodiments are used without departing from the scope of the present disclosure.

[0226] Figure 10 Another example of the determination of the start symbol and length of the PDCCH monitoring window for scheduling PDSCH reception providing RAR in the case of PRACH preamble repetition (in this example diagram, 4 repetitions) is shown. In this example, the UE runs a sliding PDCCH monitoring window, where the UE considers a fixed-size window of the same length after each PRACH preamble transmission.

[0227] In one embodiment, after an RAR failure (due to failure to detect DCI format with RA-RNTI within the RAR window, or due to incorrect decoding of the RAR message in PDSCH reception, or due to lack of any RAR message containing the preamble ID used by the UE for PRACH transmission), it is expected that the UE transmits a PRACH no later than N T，1 + 0.75 msec after the last symbol of the window or the last symbol of the last PDSCH reception (the last repetition of the PDSCH reception), where N T，1 is the duration of N1 symbols of the PDSCH reception time corresponding to the UE processing capability 1 when additional PDSCH DM-RS is configured. For μ = 0, the UE assumes N 1,0 = 14, as shown in the NR specification.

[0228] In one example, the (NR-light) UE needs to prepare to transmit the PRACH based on the above timeline, but can actually transmit the PRACH at a later time in the first available cell-specific / UE-specific NR-Light valid time slot for uplink transmission.

[0229] In one embodiment, for the RAR UL grant included in Msg2 / RAR, the content of the field and / or the field and / or bit width can be different from that of the NR UE, and / or can depend on the operating RSRP range / CE level / UE power class. Examples are provided in Table 3.

[0230] In such an embodiment, the total size (in bits) of the RAR UL grant can be the same as in the NR specification or can have a reduced size. For example, 19 bits can be used for the RAR UL grant with a reduced size, while 27 bits can be used for the NR specification grant. The UL grant size (such as 19 bits or 27 bits) can depend on the operating RSRP range / CE level and / or UE power class. Zero padding can be used if necessary to ensure a fixed-size RAR UL grant.

[0231] In one example, at least some of the methods for relaxed scheduling of Msg3 described below can be applied to PUSCH / PDSCH transmission after Msg3.

[0232] <Table 3. RAR UL Grant Content Field Sizes for NR-Light UEs>

[0233]

[0234] In one example, if frequency hopping is performed, the frequency hopping flag does not exist in the RAR UL grant.

[0235] In one example of the UL BWP of Msg3, a new field is introduced in the RAR UL grant that indicates the UL BWP index of the Msg3 PUSCH, as shown in Table 4, for example. This operation can distribute the UEs across the serving cell bandwidth, thus alleviating congestion in the initial UL BWP when there are a large number of UEs in the serving cell. In a related example, multiple (e.g., up to four) UL BWPs are indicated by a higher layer (including by SIB), and a 2-bit field for the UL BWP index in the RAR UL grant for the UE indicates the UL BWP from the four UL BWPs that the UE can use for Msg3 transmission.

[0236] In another example, a higher layer may indicate two UL BWPs, and 1 bit in the RAR UL grant indicates the UL BWP from the two UL BWPs for Msg3 transmission. The value 0 may indicate the initial UL BWP.

[0237] In yet another example, at least before the UE receives dedicated RRC configuration, a higher layer (including by SIB) provides the UE with multiple (e.g., up to 2 or 4) initial UL BWP configurations (shared with other UEs), and the UE transmits PUSCH Msg3 in one of the indices provided in the RAR UL grant among the multiple initial UL BWPs.

[0238] In one example, SIB or RRC common signaling may provide the complete configuration of the first initial UL BWP (such as a legacy / NR initial UL BWP), and the relative configuration of the second initial UL BWP in the same carrier / cell, such as one or more of relative frequency position, relative bandwidth size, etc.

[0239] In another example, one or more of the relative configuration parameters may be fixed in the system specification.

[0240] In yet another example, the UE may be indicated by UE-specific higher layer configuration to reuse one or more of the multiple initial UL BWPs as UE-dedicated / specific UL BWPs.

[0241] According to the second example, the subcarrier spacing of Msg3 PUSCH in different UL BWPs may be different, because each of the multiple UL BWPs indicated by the higher layer for Msg3 PUSCH may have a separate subcarrier spacing configuration.

[0242] For legacy NR UEs, the active UL BWP for Msg3 PUSCH transmission is indicated by the higher layer, and the corresponding subcarrier spacing is provided by the higher layer parameter subcarrierSpacing in BWP-UplinkCommon.

[0243] <Table 4. UL BWP for Msg3 PUSCH Transmission>

[0244]

[0245] In one example of frequency resource allocation, the Msg3 PUSCH frequency domain resource allocation (FDRA) field in the RAR UL grant for the UE indicates the RB allocation within the active UL BWP for Msg3 PUSCH transmission. Compared with NR UEs, the bit width of the FDRA field may be reduced, e.g., from 14 bits to 11 bits (as shown in the NR specification).

[0246] The motivation is that the UL grant for Msg3 PUSCH transmission can be targeted at UEs that support a reduced bandwidth compared to NR UEs.

[0247] In one example, except that the "cut-off" value of the size of the number of RBs of the UL BWP for PUSCH Msg3 transmission changes from 180 RBs (as shown in the NR specification) to a smaller value (such as 63 RBs), the FDRA for Msg3 PUSCH can follow the UL resource allocation type 1 in the NR specification and use consecutive / adjacent (virtual) resource blocks, so that 11 bits are required for the FDRA field in the RAR UL grant.

[0248] In another example, the FDRA for Msg3 PUSCH can follow the UL resource allocation type 2 according to the NR specification and use a (virtual) resource block group (RBG) level allocation different from that of NR UEs. According to this example, the FDRA field in the RAR UL grant indicates the RBGs allocated for Msg3 PUSCH transmission.

[0249] In yet another example, the RBG size can be determined based on the value of "configuration 2" of the RBG-size (as shown below), regardless of the actual configuration of the layer parameter rbg-Size. Therefore, no more than 9 RBGs need to be addressed, and the bit width of the FDRA field for Msg3 PUSCH transmission is reduced to 9 bits.

[0250] <Table 5. Nominal RBG Size P>

[0251] Carrier bandwidth part size Configuration 1 Configuration 2 1 to 36 2 4 37 to 72 4 8 73 to 144 8 16 145 to 275 16 16

[0252] In yet another example, the RBG size for Msg3 PUSCH can be determined based on a new configuration different from both "configuration 1" and "configuration 2" in Table 5 (as shown in the NR specification).

[0253] In one example, a (reduced-capability) UE can follow such a constraint / simplification in the FDRA for frequency resource allocation for either or both of Msg3 PUSCH and other PDSCH / PUSCH transmissions after Msg3.

[0254] In one example of time resource allocation, a limited set of time-domain resource allocations (TDRAs) can be used to schedule Msg3 PUSCH transmissions from the UE, and the size / number of bits of the TDRA field for Msg3 PUSCH transmission is reduced compared to the NR specification.

[0255] In one example, Type B TDRA that allows PUSCH transmissions not to start from the beginning of a time slot may not be supported in Table 6A and Table 7A (as shown in the NR specification).

[0256] In another example, some TDRA values of Type - A are also not supported, such as those with the minimum K2 value, e.g., due to lower UE processing capabilities, as highlighted in Table 6A and Table 7A. To clearly illustrate the new result tables to be used (for NR - Light / reduced - capability UEs), exemplary supported entries are merged and captured in Table 6B (for normal CP) and Table 7B (for extended CP) respectively. According to this example, the size / bit - width of the TDRA field in the RAR UL grant is 3 bits compared to 4 bits for NR UEs. Table 8 captures the table as shown in the NR specification.

[0257] In one example, a (reduced - capability) UE may follow this constraint / simplification in the TDRA for time resource allocation for one or both of Msg3 PUSCH and other PDSCH / PUSCH transmissions after Msg3.

[0258] In another example, the repetition count of PUSCH (including PUSCH for Msg3) is jointly encoded with the TDRA.

[0259] <Table 6A. Default PUSCH time - domain resource allocation A for normal CP>

[0260] Row index PUSCH mapping type <![CDATA[K2]]> S L 1 Type A j 0 14 2 Type A j 0 12 3 Type A j 0 10 4 Type B j 2 10 5 Type B j 4 10 6 Type B j 4 8 7 Type B j 4 6 8 Type A j+1 0 14 9 Type A j+1 0 12 10 Type A j+1 0 10 11 Type A j+2 0 14 12 Type A j+2 0 12 13 Type A j+2 0 10 14 Type B j 8 6 15 Type A j+3 0 14 16 Type A j+3 0 10

[0261] <Table 6B. New default PUSCH time - domain resource allocation A for normal CP (for NR - Light UEs)>

[0262] (NR - Light UEs do not support rows 1 to 7.)

[0263]

[0264]

[0265] <Table 7A. Default PUSCH time - domain resource allocation A for extended CP>

[0266] (NR - Light UEs do not support rows 1 to 7 and 14.)

[0267] Row index PUSCH mapping type <![CDATA[K2]]> S L 1 Type A j 0 8 2 Type A j 0 12 3 Type A j 0 10 4 Type B j 2 10 5 Type B j 4 4 6 Type B j 4 8 7 Type B j 4 6 8 Type A j+1 0 8 9 Type A j+1 0 12 10 Type A j+1 0 10 11 Type A j+2 0 6 12 Type A j+2 0 12 13 Type A j+2 0 10 14 Type B j 8 4 15 Type A j+3 0 8 16 Type A j+3 0 10

[0268] <Table 7B. New default PUSCH time - domain resource allocation A for extended CP (for NR - Light UEs)>

[0269] (NR-Light UE does not support lines 1 to 7.)>

[0270]

[0271]

[0272] <Table 8. Definition of value j>

[0273] <![CDATA[μ PUSCH > j 0 1 1 1 2 2 3 3

[0274] In an example of the reception of Msg3, a new field is introduced in the RAR UL grant to indicate the number of repetitions of the Msg3 PUSCH. The mapping of the field to the actual number of repetitions of the Msg3 PUSCH transmission can depend on the configured maximum Msg3 repetition value and a specific table depending on the RSRP range / CE level. For example, the repetition level (N Msg3 ) of the initial transmission of the Msg3 PUSCH is based on Table 9, where Y A is determined by the higher layer parameter puschMsg3-maxNumRepetition (if provided); otherwise, Y A = 8. The potential values of puschMsg3-maxNumRepetition can include {8, 16, 32}. The motivation for supporting the repetition of the Msg3 PUSCH transmission is to enhance / recover the coverage of Msg3. In an example, a similar process for indicating the number of repetitions of the PUSCH / PDSCH can be used for other PDSCH / PUSCH transmissions after Msg3.

[0275] <Table 9. Msg3 PUSCH repetition level values for NR-Light UE.>

[0276]

[0277]

[0278] In an example of the TPC command, the UE can use a limited set of TPC commands for the Msg3 PUSCH transmission, especially in the case of repetition as follows: where the Msg3 PUSCH can have the maximum power and the TPC command is actually not useful. Compared with the 3 bits used in the NR specification, the reduced number of bits (including 0 bits) can be used to indicate the TPC command for the Msg3 PUSCH. Therefore, some entries from Table 10 (as shown in the NR specification) are not used, and such exemplary entries become gray in the following table and are also explicitly indicated separately as new TPC values and new TPC commands.

[0279] <Table 10. TPC command δ for Msg3 PUSCH>msg2，b，f，c

[0280] (Does not support lines 0, 1, 6, and 7)>

[0281]

[0282] In one example of MCS, a reduced set of MCS configurations can be used. For example, compared with 4 bits in NR, 3 bits are used to indicate the MCS index, such as the first 8 MCS indexes from a legacy / NR configuration table. The motivation is that especially for repeated Msg3 PUSCH transmissions, the corresponding spectral efficiency of the operation can be in a lower range, and the modulation scheme (pi / 2BPSK or QPSK) may be sufficient.

[0283] In one example of the DL BWP for Msg3 / 4 PDCCH, a new field (e.g., with 2 bits) is introduced to indicate the DL BWP for which the UE monitors the PDCCH for possible Msg3 retransmissions and / or Msg4 transmissions and / or any other PDSCH / PUSCH transmissions after the first / initial transmission of Msg3 (e.g., configured by a temporary C-RNTI, i.e., the "TC-RNTI" and / or C-RNTI and / or MCS-C-RNTI during the random access procedure, or different RNTIs such as L-RNTI), as shown, for example, in Table 11.

[0284] The motivation is to distribute the UEs across the serving cell bandwidth and facilitate congestion control for a potentially large number of UEs on the serving cell.

[0285] In one example, up to four DL BWPs can be indicated by the higher layers, and a 2-bit field for the DL BWP index in the RAR UL grant can indicate the DL BWP used by the UE for Msg3 / 4 PDCCH reception and / or for PDCCH reception corresponding to any other PDSCH / PUSCH transmissions after the initial transmission of Msg3.

[0286] In another example, the higher layers can indicate two UL BWPs, and a 1-bit indication in the RAR UL grant indicates the UL BWP from the two UL BWPs for Msg3 transmission. A value of 0 can indicate the initial DL BWP / default DL BWP or the DL BWP for the PDCCH for Msg3 retransmission, which is the same as the DL BWP for RAR PDCCH reception.

[0287] In another example, at least before the UE receives dedicated RRC configuration, the higher layers (including by means of SIB) provide the UE with multiple (e.g., up to 2 or 4) initial DL BWP configurations (shared with other UEs), and the UE performs PDCCH monitoring corresponding to any other PDSCH / PUSCH transmissions after the initial transmission in Msg3 and / or Msg3 / 4 PDCCH monitoring in one of the multiple initial DL BWPs in which it provides its index in the RAR UL grant. For example, SIB or RRC common signaling may provide the complete configuration of a first initial DL BWP (such as a legacy / NR initial DL BWP), and the relative configuration of a second initial DL BWP in the same carrier / cell, such as one or more of relative frequency position, relative bandwidth size, etc.

[0288] In another example, one or more of the relative configuration parameters may be fixed in the system specification. In yet another example, the UE may be instructed by UE-specific higher layer configuration to reuse one or more of the multiple initial DL BWPs as UE-dedicated / specific DL BWPs.

[0289] In one example, a UE may be provided with multiple search space sets for monitoring PDCCHs for scheduling Msg3 retransmission and / or Msg4 reception and / or any other PDSCH / PUSCH transmissions after the initial transmission of Msg3. The multiple search space sets may be mapped to corresponding multiple CORESETs, where the multiple CORESETs may have different numbers of symbols to facilitate different coverage (enhancement) levels of the PDCCH. For example, a first CORESET from the multiple CORESETs may have a duration of 1 to 3 symbols, while a second CORESET may have a duration of 4 to 6 (or 1 to 6 or a subset thereof) OFDM symbols. For example, the set of multiple CORESETs may be the same as those used for RAR PDCCH reception in the previous embodiments. In another example, the set of multiple CORESETs may have the same time-domain duration as those of the CORESETs used for RAR PDCCH reception, e.g., the same number of symbols, as described in the previous embodiments. In one example, the UE may determine the search space set (and the corresponding CORESET) for monitoring the PDCCH based on the RSRP or the CE level. For example, if the RSRP for the DL RS (e.g., SSB or CSI-RS) is less than or equal to a threshold, the UE monitors the PDCCH for scheduling the aforementioned PDSCH / PUSCH according to the search space set associated with the CORESET having a first number of symbols (such as 1 to 3 symbols), and if the RSRP for the DL RS (e.g., SSB or CSI-RS) is greater than the threshold, the UE monitors the PDCCH for scheduling the aforementioned PDSCH / PUSCH according to the search space set associated with the CORESET having a second number of symbols (such as 1 to 6 symbols (or 4 to 6 symbols or a subset thereof)). Herein: the threshold may be provided by the specification and / or SIB signaling (such as SIB1) and / or common RRC signaling, and / or determined by the UE based on predetermined or configured rules and / or formulas; the configuration of the multiple search space sets (possibly) except for the default search space set determined according to the MIB and used for the scheduling of the SIB may be provided by the specification and / or SIB signaling (such as SIB1) and / or common RRC signaling, and / or determined by the UE based on predetermined or configured rules and / or formulas. In one example, the frequency resource allocation of each CORESET from the set of multiple CORESETs may be the same as those of the CORESETs used for RAR PDCCH reception, as described in the previous embodiments. In another example, the frequency resource allocation of each CORESET from the set of multiple CORESETs may be an offset compared to those of a set of multiple CORESETs (corresponding CORESETs) used for RAR PDCCH reception as described in the previous embodiments.According to this example, compared with a set of multiple CORESETs (corresponding CORESETs) for RAR PDCCH reception as described in the previous embodiments, a common / same offset value or different offset values can be configured for the frequency-domain resource allocation of each CORESET from the set of multiple CORESETs. Additionally, the configuration of the offset value can be provided by the specification and / or SIB signaling (such as SIB1) and / or common RRC signaling, and / or determined by the UE based on predetermined or configured rules and / or formulas. In another example, the set of multiple CORESETs for monitoring / receiving PDCCH corresponding to Msg3 retransmission and / or Msg4 reception and / or any other PDSCH / PUSCH transmission after the initial transmission of Msg3 can be configured in one or more of the multiple (initial) DL BWPs indicated by the RAR uplink grant field. For example, the first CORESET (or the first subset of CORESETs) from the set of multiple CORESETs can be configured on the first initial DL BWP, while the second CORESET (or the second subset of CORESETs) from the set of multiple CORESETs can be configured on the second initial DL BWP. A CORESET can be associated with PDCCH monitoring through the configuration of the corresponding search space set.

[0290] According to this example, the subcarrier spacing for Msg3 / 4 PDCCH reception can be different in different DL BWPs, because each of the multiple DL BWPs indicated by the higher layer for Msg3 / 4 PDCCH reception and / or PDCCH reception corresponding to any other PDSCH transmission after the initial transmission of Msg3 can have a separate configuration of subcarrier spacing.

[0291] In one example, a new field in the RAR UL grant corresponding to the DL BWP for Msg3 / 4 PDCCH monitoring indicates the DL BWP for the first time slot / first repetition for receiving PDCCH transmission for Msg3 retransmission and / or Msg4 transmission and / or any other PDSCH transmission after the initial transmission of Msg3. The remaining time slots / remaining repetitions for PDCCH monitoring for Msg3 retransmission and / or Msg4 transmission and / or any other PDSCH transmission after the initial transmission of Msg3 can be on other DL BWPs, following the hopping pattern specified or indicated by the higher layer and / or the BWP switching command in the DCI format scheduling Msg3 retransmission and / or Msg4 transmission and / or any other PDSCH transmission after the initial transmission of Msg3.

[0292] <Table 11. DL BWP for Msg3 / 4 PDCCH Reception>

[0293]

[0294] In an example of the SRS request, a new field is introduced for the SRS request, for example, having 1 to 3 bits. This can help with future beam management and scheduling. For example, such an SRS request field can replace or supplement the CSI request field.

[0295] In one embodiment, referring to the time slot used for PUSCH transmission scheduled by the RAR UL grant, if the UE receives the last repetition of the PDSCH with the RAR message for the corresponding PRACH transmission from the UE, which ends in time slot n, the UE transmits the first repetition of the Msg3 PUSCH in the first valid time slot, as determined by the higher layer configuration, which starts at or after n + k2 + Δ, where k2 and Δ are provided in the NR specification.

[0296] In one example, if the subcarrier spacing (SCS) used for RAR PDSCH reception is different from the SCS used for Msg3 PUSCH transmission, the timing relationship is adjusted by the relative SCS between the PDSCH and the PUSCH to where μ PUSCH and μ PDSCH are the subcarrier spacing configurations for the PUSCH and the PDSCH, respectively.

[0297] In one embodiment, the UE may assume that the minimum time between the last symbol of the PDSCH reception that delivers the last repetition of the RAR message with the RAR UL grant and the first symbol of the first reception of the corresponding PUSCH transmission scheduled by the RAR UL grant is equal to N T，1 + N T，2 + 0.5 msec, where N T，1 is the duration of N1 symbols of the PDSCH reception time corresponding to the UE processing capability 1 when additional PDSCH DM-RS is configured, N T，2 is the duration of N2 symbols of the PUSCH preparation time corresponding to the UE processing capability 1 (as shown in the NR specification), and for determining the minimum time, the UE considers N1 and N2 corresponding to the smaller of the SCS configurations of the PDSCH and the PUSCH. For μ = 0, the UE assumes N 1，0 = 14 (as shown in the NR specification).

[0298] In another embodiment, in response to the RAR UL grant scheduling the Msg3 PUSCH transmission when the UE has not been provided with a C-RNTI, the UE attempts to detect the DCI format with a CRC scrambled by the corresponding TC-RNTI that schedules the PDSCH including the UE contention resolution identity, such as DCI format 1_0 (as shown in the NR specification).

[0299] In response to receiving a PDSCH with a UE contention resolution identity, the UE transmits HARQ-ACK information in the PUCCH. The PUCCH transmission is within the same active UL BWP as the PUSCH transmission. The minimum time between the last symbol of the last repetition of the PDSCH reception and the first symbol of the corresponding PUCCH transmission with HARQ-ACK information is equal to N T，1 + 0.5 msec. N T，1 is the duration of N1 symbols corresponding to the PDSCH reception time for UE processing capability 1 when additional PDSCH DM-RS is configured. For μ = 0, the UE assumes N 1,0 = 14 (as shown in the NR specification).

[0300] In another embodiment, when detecting a DCI format (such as DCI format 0_0) with a CRC scrambled by a TC-RNTI provided in a corresponding RAR message in response to a PUSCH transmission scheduled by an RAR UL grant, as described in the NR specification, or a corresponding PUSCH retransmission scheduled by a DCI format (as described in the NR specification), the UE may assume that the PDCCH providing the DCI format has the same DM-RS antenna port quasi-co-location property as that of the SS / PBCH block associated with the UE's PRACH in the NR specification, regardless of whether the UE is provided with the TCI-state of the CORESET used by the UE to receive the PDCCH with this DCI format.

[0301] In one example, the PDSCH reception with a UE contention resolution identity has the same DM-RS antenna port quasi-co-location property as the SS / PBCH block associated with the UE's PRACH (as described in the NR specification), as described in the NR specification.

[0302] In one example, UE distribution / congestion control during the initial access of NR-Light UEs is provided in Tables 12A and 12B.

[0303]

[0304]

[0305] <Table 12B. MIB Field Description>

[0306]

[0307] In one embodiment, after the UE is allowed to access the serving cell based on the Master Information Block (MIB) parameter cellBarred with the value "notBarred", the UE checks and reinterprets the MIB parameter intraFreqReselection to determine the initial DL / UL BWP of the serving cell and / or CORESET#0.

[0308] In one example, if the MIB parameter intraFreqReselection is set to "allowed", the UE may maintain / preempt the initial DL / UL BWP as indicated by pdcch-ConfigSIB1 in NR and use CORESET#0. However, if the MIB parameter intraFreqReselection is set to "notAllowed", the UE determines that the UE needs to preempt another portion of the system bandwidth (another DL / UL BWP other than the initial DL / UL BWP) and / or use a different CORESET#0 (e.g., CORESET#0-light) by reinterpreting the configuration in pdcch-ConfigSIB1 based on an alternative specified table (e.g., for the size and location of CORESET#0, SSB, and CORESET#0-light multiplexing, etc.).

[0309] In another example, the UE access behavior is opposite to the behavior described in the previous example for the MIB parameter intraFreqReselection values "allowed" and "notAllowed". It should be noted that when another MIB parameter cellBarred is set to the value "Barred", the NR specification has specified certain UE behaviors based on the MIB parameter intraFreqReselection.

[0310] However, for the case where the MIB parameter cellBarred is set to the value "notBarred", the NR specification does not specify UE behavior based on the MIB parameter intraFreqReselection. This is why this MIB parameter may be used for further reinterpretation in the case of NR-Light / non-traditional UEs. It should be noted that it is expected that traditional NR UEs do not perform any such reinterpretation.

[0311] This solution can move all NR-Light UEs / low-capability / non-traditional UEs to different / separate DL / UL BWPs and / or CORESET#0. This solution may be combined with other UE IDs (such as the global UE ID, etc.) such that only certain groups of NR-Light UEs perform this reinterpretation while other NR-Light UEs do not perform this behavior.

[0312] In one example, all NR-Light / non-conventional UEs execute the solution provided in this embodiment to move to different / separate DL / UL BWPs and / or CORESET#0, but each group of NR-Light UEs / low-capability / non-conventional UEs can pre-empt / remain in different DL / UL BWPs and / or CORESET#0 based on other UE IDs. This solution can further assist in congestion control and UE distribution on the system bandwidth during initial access for NR-Light UEs.

[0313] Figure 11 An example congestion control and UE distribution 1100 during initial access of an NR-Light UE in accordance with an embodiment of the present disclosure is shown. Figure 11 The embodiment of the congestion control and UE distribution 1100 shown is for illustration only. Figure 11 One or more of the components shown may be implemented in a dedicated circuit configured to perform the functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the functions. Other embodiments are used without departing from the scope of the present disclosure.

[0314] As Figure 11 shown, in step 1110, the UE receives and reads the MIB from the PBCH. In step 1120, the UE determines whether the MIB parameter cellBarred has a value equal to "barred". If the UE determines that the MIB parameter cellBarred has a value equal to "barred", then in step 1130, the UE operates based on another MIB parameter intraFreqReselection as in the NR specification. However, if the UE determines that the MIB parameter cellBarred has a value equal to "notBarred", then in step 1140, the UE considers the value of the MIB parameter intraFreqReselection.

[0315] If the UE determines that the MIB parameter ntraFreqReselection has a value equal to "allowed", then in step 1150, as indicated by pdcch-ConfigSIB1 in the NR specification, the UE pre-empts the initial DL / UL BW and uses CORESET #0. However, if the UE determines that the MIB parameter ntraFreqReselection has a value equal to "notAllowed", then in step 1160, the UE re-interprets pdcch-ConfigSIB1 to pre-empt a DL / UL BWP other than the initial DL / UL BWP and uses a different CORESET #0 (e.g., CORESET #0-Light).

[0316] Although the present disclosure has been described with exemplary embodiments, various changes and modifications can be proposed to those skilled in the art. The present disclosure is intended to embrace such changes and modifications that fall within the scope of the appended claims. No description in this application should be construed as implying that any particular element, step, or function is an essential element that must be included within the scope of the claims. The scope of the patent subject matter is defined only by the claims.

Claims

1. A method for communication by a Reduced-Capability User Equipment (Redcap UE), comprising: Receive a system information block (SIB) from a base station, the SIB including a plurality of initial uplink (UL) bandwidth parts (BWPs) and a plurality of initial downlink (DL) BWPs; Transmit a physical random access channel (PRACH) preamble to the base station; Receive a random access response (RAR) from the base station using an initial DL BWP among the plurality of initial DL BWPs, wherein the RAR includes a value indicating the number of repetitions of Msg3 transmission on a physical uplink shared channel (PUSCH); Transmit a contention resolution message Msg3 to the base station using an initial UL BWP among the plurality of initial UL BWPs; and Receive a contention resolution response message MSG4 from the base station using an initial DL BWP among the plurality of initial DL BWPs, wherein, when a higher layer parameter is configured, the value indicating the number of repetitions of Msg3 transmission is one of four values determined by the higher layer parameter, and wherein, when the higher layer parameter is not configured, the value indicating the number of repetitions of Msg3 transmission is one of four pre-determined values.

2. The method according to claim 1, wherein, The initial DL BWP is a UE-specific DL BWP, and the initial UL BWP is a UE-specific UL BWP.

3. The method according to claim 1, wherein, The number of repetitions of Msg3 transmission is used for the repetition of PUSCH transmission after Msg3 transmission.

4. The method according to claim 1, wherein, The window for monitoring the physical downlink control channel (PDCCH) associated with the RAR starts at the first symbol of the earliest control resource set (CORESET), and the UE is configured to receive the PDCCH for a type 1-PDCCH common search space (CSS) set, which is at least one symbol after the last symbol of the last PRACH occasion corresponding to the PRACH transmission.

5. A method for communication by a base station, comprising: Send a system information block (SIB) to a reduced-capability user equipment (Redcap UE), the SIB including a first initial uplink (UL) bandwidth part (BWP) for the Redcap UE and a first initial downlink (DL) BWP for the Redcap UE; Receive a physical random access channel (PRACH) preamble from the Redcap UE; Send a random access response (RAR) to the Redcap UE using an initial DL BWP among the plurality of initial DL BWPs, wherein the RAR includes a value indicating the number of repetitions of Msg3 transmission on a physical uplink shared channel (PUSCH); Receive a contention resolution message Msg3 from the Redcap UE using an initial UL BWP among the plurality of initial UL BWPs; and Send a contention resolution response message Msg4 to the Redcap UE using an initial DL BWP among the plurality of initial DL BWPs, wherein, when a higher layer parameter is configured, the value indicating the number of repetitions of Msg3 transmission is one of four values determined by the higher layer parameter, and Among them, in the case where high-layer parameters are not configured, the value indicating the number of repetitions of Msg3 transmission is one of four pre-determined values.

6. The method according to claim 5, wherein, The initial DL BWP is a UE-specific DL BWP, and the initial UL BWP is a UE-specific UL BWP.

7. The method according to claim 5, wherein, The number of repetitions of Msg3 transmission is used for the repetition of PUSCH transmission after the Msg3 transmission.

8. The method of claim 5, wherein, The window for monitoring the PDCCH associated with the RAR starts at the first symbol of the earliest control resource set CORESET, and the UE is configured to receive the physical downlink control channel PDCCH for the type 1-PDCCH common search space CSS set, and the type 1-PDCCH CSS set is at least one symbol after the last symbol of the last PRACH occasion corresponding to the PRACH transmission.

9. A Reduced-Capability User Equipment (Redcap UE), comprising: Transceiver; And A processor configured to control to: Receive a system information block SIB including a plurality of initial uplink UL bandwidth parts BWPs and a plurality of initial downlink DL BWPs from a base station; Send a physical random access channel PRACH preamble to the base station; Receive a random access response RAR from the base station using the initial DL BWP among the plurality of initial DL BWPs, where the RAR includes a value indicating the number of repetitions of Msg3 transmission on a physical uplink shared channel PUSCH; Send a contention resolution message Msg3 to the base station using the initial UL BWP among the plurality of initial UL BWPs; and Receive a contention resolution response message MSG4 from the base station using the initial DL BWP among the plurality of initial DL BWPs, Among them, in the case where high-layer parameters are configured, the value indicating the number of repetitions of Msg3 transmission is one of four values determined by the high-layer parameters, and Among them, in the case where high-layer parameters are not configured, the value indicating the number of repetitions of Msg3 transmission is one of four pre-determined values.

10. The Redcap UE according to claim 9, wherein, The initial DL BWP is a UE-specific DL BWP, and the initial UL BWP is a UE-specific UL BWP.

11. The Redcap UE according to claim 9, wherein, The number of repetitions of Msg3 transmission is used for the repetition of PUSCH transmission after the Msg3 transmission.

12. The Redcap UE according to claim 9, wherein, The window for monitoring the PDCCH associated with the RAR starts at the first symbol of the earliest control resource set CORESET, and the UE is configured to receive the physical downlink control channel PDCCH for the type 1-PDCCH common search space CSS set, and the type 1-PDCCH CSS set is at least one symbol after the last symbol of the last PRACH occasion corresponding to the PRACH transmission.

13. A base station, comprising: Transceiver; And A processor configured to control to: Send a system information block SIB to a reduced-capability user equipment Redcap UE, where the SIB includes a first initial uplink UL bandwidth part BWP for the Redcap UE and a first initial downlink DL BWP for the Redcap UE; Receive a Physical Random Access Channel (PRACH) preamble from the Redcap UE; Send a Random Access Response (RAR) to the Redcap UE using an initial Downlink (DL) BWP among the multiple initial DL BWPs, where the RAR includes a value indicating the number of repetitions of Msg3 transmission on a Physical Uplink Shared Channel (PUSCH); Receive a contention resolution message Msg3 from the Redcap UE using an initial Uplink (UL) BWP among the multiple initial UL BWPs; and Send a contention resolution response message Msg4 to the Redcap UE using an initial DL BWP among the multiple initial DL BWPs, where, when a high-layer parameter is configured, the value indicating the number of repetitions of Msg3 transmission is one of four values determined by the high-layer parameter, and where, when no high-layer parameter is configured, the value indicating the number of repetitions of Msg3 transmission is one of four pre-determined values.

14. The base station according to claim 13, wherein, The initial DL BWP is a UE-specific DL BWP, and the initial UL BWP is a UE-specific UL BWP.

15. The base station according to claim 13, wherein, The window for monitoring the Physical Downlink Control Channel (PDCCH) associated with the RAR starts at the first symbol of the earliest Control Resource Set (CORESET), and the UE is configured to receive a PDCCH for a Type 1-PDCCH Common Search Space (CSS) set, which is at least one symbol after the last symbol of the last PRACH occasion corresponding to the PRACH transmission.

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