Early CSI reporting during RACH procedures

Abstract

The invention relates to supporting early CSI reporting during RACH procedures. In some embodiments, a user equipment (UE) is provided, the user equipment (UE) comprising: at least one antenna; at least one radio coupled to the at least one antenna; and a processor coupled to the at least one radio; wherein the UE is configured to perform operations comprising: receiving, from a base station, a trigger for triggering reporting of CSI during a RACH procedure; and reporting the CSI to the base station during the RACH procedure.

Description

Technical Field

[0001] The present application generally relates to wireless communication systems, including user equipment, base stations, methods, apparatuses and media for supporting early CSI reporting during a RACH procedure. Background Art

[0002] Wireless mobile communication technologies use various standards and protocols to send data between base stations and wireless communication devices. Wireless communication system standards and protocols may include, for example, the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) (e.g., 4G), 3GPP New Radio (NR) (e.g., 5G), and the IEEE 802.11 standard for wireless local area networks (WLANs) (often referred to by industry groups as Wi-Fi). ® ).

[0003] As envisioned by 3GPP, different wireless communication system standards and protocols may use various radio access networks (RANs) to communicate between base stations of the RAN (which may also sometimes be referred to as RAN nodes, network nodes, or simply nodes) and wireless communication devices referred to as user equipment (UE). The 3GPP RAN may include, for example, Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE) RAN (GERAN), Universal Terrestrial Radio Access Network (UTRAN), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and / or Next Generation Radio Access Network (NG-RAN).

[0004] Each RAN may use one or more radio access technologies (RATs) for communication between base stations and UEs. For example, GERAN implements GSM and / or EDGE RAT, UTRAN implements Universal Mobile Telecommunications System (UMTS) RAT or other 3GPP RAT, E-UTRAN implements LTE RAT (sometimes referred to as LTE), and NG-RAN implements NR RAT (sometimes referred to as 5G RAT, 5G NR RAT, or simply NR in this document). In some deployments, E-UTRAN may also implement NR RAT. In some deployments, NG-RAN may also implement LTE RAT.

[0005] A base station used by a RAN may correspond to the RAN. An example of an E-UTRAN base station is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (also often denoted as an evolved Node B, enhanced Node B, eNodeB, or eNB). An example of an NG-RAN base station is a Next Generation Node B (also sometimes referred to as an a or g Node B or gNB).

[0006] The RAN provides its communication services together with external entities through its connection with the Core Network (CN). For example, E-UTRAN may utilize the Evolved Packet Core (EPC) while NG-RAN may utilize the 5G Core Network (5GC). Summary of the invention

[0007] Embodiments are directed to user equipment, base stations, methods, apparatuses, and media for supporting early CSI reporting during a RACH procedure.

[0008] According to the techniques described herein, early CSI reporting during a RACH procedure is supported. A user equipment (UE) may report CSI to a base station during a RACH procedure. The UE may report CSI in Msg3 for a 4-step RACH procedure, in MsgA for a 2-step RACH procedure, or in Msg3 during fallback operation for a 2-step RACH procedure.

[0009] In some embodiments, the UE may receive a trigger for triggering early CSI reporting. The trigger may be included in system information (SI) or radio resource control (RRC) configuration, medium access control (MAC) control element (CE) or downlink control information (DCI).

[0010] In some implementations, the UE may receive a CSI reporting configuration from the base station. The CSI reporting configuration may include at least one of: (i) a reference signal configuration for CSI measurement, or (ii) a reporting amount configuration for CSI reporting.

[0011] In some embodiments, timeline constraints are considered. The timeline constraints may include the minimum time required for the UE to measure CSI and generate a CSI report. In some embodiments, the timeline constraints may additionally include the minimum time required for the UE to complete processing the trigger.

[0012] This disclosure is intended to provide a brief overview of some of the topics described in this document. Therefore, it should be understood that the above features are only examples and should not be construed as narrowing the scope or essence of the topics described herein in any way. Other features, aspects, and advantages of the topics described herein will become apparent through the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] To easily identify the discussion of any particular element or action, the most significant digit(s) in a reference number refers to the drawing number that first introduces the element.

[0014] Figure 1 An example architecture of a wireless communication system according to embodiments disclosed herein is shown.

[0015] Figure 2 A system for performing signaling between a wireless device and a network device according to embodiments disclosed herein is shown.

[0016] Figure 3A An example flow diagram of a 4-step random access channel (RACH) according to embodiments disclosed herein is shown.

[0017] Figure 3B An example flow diagram of 2-step RACH according to embodiments disclosed herein is shown.

[0018] Figure 4A The MAC payload of a random access response (RAR) defined in the prior art is shown.

[0019] Figure 4B The content of a 27-bit UL grant as defined in the prior art is shown.

[0020] Figure 5A An example reference signal configuration according to embodiments disclosed herein is shown.

[0021] Figure 5B Another example reference signal configuration according to embodiments disclosed herein is shown.

[0022] Figure 6 Example minimum time constraints for fallback operation for a 4-step RACH procedure or for a 2-step RACH procedure according to embodiments disclosed herein are shown.

[0023] Figure 7 A method performed by a UE according to an embodiment disclosed herein is shown.

[0024] Figure 8 A method performed by a base station according to an embodiment disclosed herein is shown.

[0025] Fig. 9 A method performed by a UE according to an embodiment disclosed herein is shown.

[0026] Fig.10 A method performed by a base station according to an embodiment disclosed herein is shown.

[0027] Fig.11 A method performed by a UE according to an embodiment disclosed herein is shown.

[0028] Fig.12 A method performed by a base station according to an embodiment disclosed herein is shown. DETAILED DESCRIPTION

[0029] Various embodiments are described with reference to UE. However, reference to UE is provided for illustrative purposes only. The example embodiments may be used with any electronic component that can establish a connection with a network and is configured with hardware, software and / or firmware for exchanging information and data with the network. Therefore, UE as described herein is used to represent any suitable electronic component.

[0030] Figure 1 An example architecture of a wireless communication system 100 according to embodiments disclosed herein is illustrated. The description provided below is for an example wireless communication system 100 operating in conjunction with the LTE system standard and / or the 5G or NR system standard provided in the 3GPP technical specifications.

[0031] like Figure 1 As shown, wireless communication system 100 includes UE 102 and UE 104 (although any number of UEs may be used). In this example, UE 102 and UE 104 are illustrated as smartphones (e.g., handheld touch screen mobile computing devices capable of connecting to one or more cellular networks), but may also include any mobile or non-mobile computing device configured for wireless communication.

[0032] UE 102 and UE 104 may be configured to be communicatively coupled to RAN 106. In an embodiment, RAN 106 may be NG-RAN, E-UTRAN, etc. UE 102 and UE 104 utilize connections (or channels) (shown as connection 108 and connection 110, respectively) with RAN 106, where each connection (or channel) includes a physical communication interface. RAN 106 may include one or more base stations, such as base station 112 and base station 114, to implement connection 108 and connection 110.

[0033] In this example, connections 108 and 110 are air interfaces to achieve such communication coupling and may conform to the RAT used by the RAN 106, such as, for example, LTE and / or NR. In the case where the RAN 106 is an NTN-based NG-RAN architecture, connections 108 and 110 are NR Uu interfaces.

[0034] In some embodiments, UE 102 and UE 104 may also directly exchange communication data via side link interface 116. UE 104 is shown as being configured to access an access point (shown as AP 118) via connection 120. By way of example, connection 120 may include a local wireless connection, such as a connection conforming to any IEEE 802.11 protocol, wherein AP 118 may include a Wi-Fi ® In this example, AP 118 may be connected to another network (eg, the Internet) without going through CN 124.

[0035] In an embodiment, UE 102 and UE 104 may be configured to communicate with each other or with base station 112 and / or base station 114 over a multi-carrier communication channel using orthogonal frequency division multiplexing (OFDM) communication signals according to various communication techniques, such as, but not limited to, orthogonal frequency division multiple access (OFDMA) communication techniques (e.g., for downlink communication) or single carrier frequency division multiple access (SC-FDMA) communication techniques (e.g., for uplink and ProSe or sidelink communication), although the scope of the embodiments is not limited in this respect. The OFDM signal may include multiple orthogonal subcarriers.

[0036] In some embodiments, all or part of base station 112 or base station 114 may be implemented as one or more software entities running on a server computer as part of a virtual network. In addition, or in other embodiments, base station 112 or base station 114 may be configured to communicate with each other via interface 122. In an embodiment where wireless communication system 100 is an LTE system (e.g., when CN124 is an EPC), interface 122 may be an X2 interface. The X2 interface may be defined between two or more base stations (e.g., two or more eNBs, etc.) connected to the EPC and / or between two eNBs connected to the EPC. In an embodiment where wireless communication system 100 is an NR system (e.g., when CN 124 is a 5GC), interface 122 may be an Xn interface. The Xn interface is defined between two or more base stations (e.g., two or more gNBs, etc.) connected to a 5GC, between a base station 112 (e.g., a gNB) and an eNB connected to a 5GC, and / or between two eNBs connected to a 5GC (e.g., CN 124).

[0037] The RAN 106 is shown as being communicatively coupled to the CN 124. The CN 124 may include one or more network elements 126 configured to provide various data and telecommunication services to customers / subscribers (e.g., UE 102 and users of UE 104) connected to the CN 124 via the RAN 106. The components of the CN 124 may be implemented in one physical device or separate physical devices including components for reading and executing instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium).

[0038] In an embodiment, CN 124 may be an EPC, and RAN 106 may be connected to CN 124 via an S1 interface 128. In an embodiment, S1 interface 128 may be divided into two parts: an S1 user plane (S1-U) interface that carries traffic data between base station 112 or base station 114 and a serving gateway (S-GW); and an S1-MME interface that is a signaling interface between base station 112 or base station 114 and a mobility management entity (MME).

[0039] In an embodiment, CN 124 may be a 5GC, and RAN 106 may be connected to CN 124 via an NG interface 128. In an embodiment, NG interface 128 may be divided into two parts: an NG user plane (NG-U) interface that carries service data between base station 112 or base station 114 and a user plane function (UPF); and an S1 control plane (NG-C) interface that is a signaling interface between base station 112 or base station 114 and an access and mobility management function (AMF).

[0040] Generally speaking, the application server 130 may be an element that provides applications (e.g., packet-switched data services) that use Internet Protocol (IP) bearer resources with the CN 124. The application server 130 may also be configured to support one or more communication services (e.g., VoIP sessions, group communication sessions, etc.) for the UE 102 and the UE 104 via the CN 124. The application server 130 may communicate with the CN 124 via an IP communication interface 132.

[0041] Figure 2 A system 200 for performing signaling 234 between a wireless device 202 and a network device 218 according to embodiments disclosed herein is shown. The system 200 may be part of a wireless communication system as described herein. The wireless device 202 may be, for example, a UE of a wireless communication system. The network device 218 may be, for example, a base station (e.g., an eNB or a gNB) of a wireless communication system.

[0042] The wireless device 202 may include one or more processors 204. The processor 204 may execute instructions to perform various operations of the wireless device 202, as described herein. The processor 204 may include one or more baseband processors implemented using, for example, a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0043] The wireless device 202 may include a memory 206. The memory 206 may be a non-transitory computer-readable storage medium that stores instructions 208 (which may include, for example, instructions executed by the processor 204). The instructions 208 may also be referred to as program code or a computer program. The memory 206 may also store data used by the processor 204 and results calculated by the processor.

[0044] The wireless device 202 may include one or more transceivers 210 that may use radio frequency (RF) transmitter and / or receiver circuitry that uses an antenna 212 of the wireless device 202 to facilitate signaling (e.g., signaling 234) to and / or from the wireless device 202 with other devices (e.g., network device 218) according to a corresponding RAT.

[0045] The wireless device 202 may include one or more antennas 212 (e.g., one, two, four, or more). For embodiments with multiple antennas 212, the wireless device 202 may utilize the spatial diversity of such multiple antennas 212 to transmit and / or receive multiple different data streams on the same time-frequency resources. This behavior may be referred to as, for example, multiple-input multiple-output (MIMO) behavior (referring to the multiple antennas used at each of the transmitting device and the receiving device to implement this aspect). MIMO transmission by the wireless device 202 may be implemented based on precoding (or digital beamforming) applied at the wireless device 202, which multiplexes the data streams across the antennas 212 based on known or assumed channel characteristics so that each data stream is received at an appropriate signal strength relative to the other streams and at a desired location in the spatial domain (e.g., the location of the receiver associated with the data stream). Certain embodiments may use a single-user MIMO (SU-MIMO) approach (where the data streams are all directed to a single receiver) and / or a multi-user MIMO (MU-MIMO) approach (where separate data streams may be directed to separate (different) receivers in different locations in the spatial domain).

[0046] In certain embodiments with multiple antennas, the wireless device 202 may implement analog beamforming techniques whereby the phases of signals transmitted by the antennas 212 are relatively adjusted so that the (joint) transmissions of the antennas 212 can be directed (this is sometimes referred to as beam steering).

[0047] The wireless device 202 may include one or more interfaces 214. The interface 214 may be used to provide input to the wireless device 202 or output from the wireless device. For example, a wireless device 202 that is a UE may include an interface 214, such as a microphone, a speaker, a touch screen, buttons, etc., to allow a user of the UE to input and / or output to the UE. Other interfaces of such a UE may be composed of transmitters, receivers, and other circuit systems that allow communication between the UE and other devices (for example, in addition to the transceiver 210 / antenna 212 described above), and may be based on known protocols (for example, Wi-Fi ® ,Bluetooth ® etc.) to perform the operation.

[0048] The network device 218 may include one or more processors 220. The processor 220 may execute instructions to perform various operations of the network device 218, as described herein. The processor 204 may include one or more baseband processors implemented using, for example, a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

[0049] The network device 218 may include a memory 222. The memory 222 may be a non-transitory computer-readable storage medium that stores instructions 224 (which may include, for example, instructions executed by the processor 220). The instructions 224 may also be referred to as program code or a computer program. The memory 222 may also store data used by the processor 220 and results calculated by the processor.

[0050] The network device 218 may include one or more transceivers 226, which may include RF transmitter and / or receiver circuitry that uses an antenna 228 of the network device 218 to facilitate signaling (e.g., signaling 234) to and / or from the network device 218 with other devices (e.g., wireless device 202) according to a corresponding RAT.

[0051] The network device 218 may include one or more antennas 228 (eg, one, two, four, or more). In embodiments with multiple antennas 228, the network device 218 may perform MIMO, digital beamforming, analog beamforming, beam steering, etc. as described.

[0052] The network device 218 may include one or more interfaces 230. The interface 230 may be used to provide input to or output from the network device 218. For example, the network device 218 as a base station may include an interface 230 composed of a transmitter, a receiver and other circuits (e.g., in addition to the transceiver 226 / antenna 228 described above), which enables the base station to communicate with other equipment in the core network and / or enables the base station to communicate with external networks, computers, databases, etc., in order to achieve the purpose of performing operations, management and maintenance of the base station or other equipment operably connected to the base station.

[0053] Satellite maximizes the inherent value of 5G networks by solving coverage issues and providing difficult use cases that ground-based infrastructure alone cannot solve. 5G standards make non-terrestrial networks (NTNs) including satellite segments a recognized part of the 5G connectivity infrastructure.

[0054] NTN is used to deliver 5G / NR services via space (satellite) or air (aerial platform) to places where it is technically difficult or too costly to deliver using terrestrial networks (TN). Some examples of these places are remote areas such as deep in the forest where terrestrial delivery is too costly, or remote islands or ships where terrestrial connectivity is almost impossible.

[0055] In order to establish uplink synchronization and radio resource control (RRC) connection between a UE and a base station (e.g., gNB), the UE must perform a random access channel (RACH) random access procedure.

[0056] In the current NR, two types of random access procedures are supported, including: (1) Type 1 random access procedure, i.e., 4-step RACH, and (2) Type 2 random access procedure, i.e., 2-step RACH. When 2-step RACH fails, fallback to 4-step RACH is supported.

[0057] Figure 3A An example flow chart of a 4-step RACH according to an embodiment disclosed herein is shown. Figure 3A As shown, the 4-step RACH includes the following steps:

[0058] Step 1: UE sends Msg1 (or preamble) to gNB. Specifically, UE sends PRACH preamble to gNB, and then UE monitors type 1-PDCCH CSS (Physical Downlink Control Channel Common Search Space) for DCI format 1_0 with cyclic redundancy check (CRC) scrambled by corresponding RA-RNTI;

[0059] Step 2: The gNB sends Msg2 (or Random Access Response (RAR)) to the UE. Specifically, the gNB responds to the UE sending the PRACH preamble by scheduling the RAR transmission in which the UL grant is provided. The UL grant is provided to schedule the UE to send Msg3.

[0060] Step 3: The UE sends Msg3 according to the UL grant in the RAR.

[0061] Step 4: gNB sends Msg4 after decoding Msg3.

[0062] Figure 3B An example flow diagram of 2-step RACH according to embodiments disclosed herein is shown.

[0063] like Figure 3B As shown, the 2-step RACH includes the following steps:

[0064] Step A: The UE sends MsgA to the gNB. Specifically, the UE sends the PRACH preamble and data (PUSCH) in MsgA, and then the UE monitors the Type 1-PDCCH CSS for DCI format 1_0 with CRC scrambled by the corresponding MsgB-RNTI. MsgA can be represented as a combination of Msg1+Msg3.

[0065] Step B: gNB sends MsgB after decoding MsgA. In MsgB, UL grant is provided. MsgA can be represented as a combination of Msg2+Msg4.

[0066] Figure 4A The MAC payload of RAR as defined in the prior art is shown. It can be seen that the 27-bit UL grant is part of the RAR (Msg2) to schedule the UE to send Msg3.

[0067] Figure 4B The content of the 27-bit UL grant as defined in the prior art is shown. Figure 4B As shown, a 1-bit "CSI request" field is provided. However, the "CSI request" field is reserved and is unused. That is, it is not defined how to use the "CSI request" field.

[0068] Currently, early CSI reporting during the RACH procedure is not supported. However, in order to reduce the delay of the RACH procedure, improve the reliability of the RACH procedure and improve further communications, it is beneficial for the UE to report CSI as early as possible.

[0069] For example, early CSI reporting may be useful especially for FR2 (frequency range 2, ie mmWave) if the UE can update its preferred beam as early as possible.

[0070] The disclosure herein discusses that the UE may report CSI in Msg3 for a Type 1 random access procedure, in MsgA for a Type 2 random access procedure, or in Msg3 during a fallback operation for a Type 2 random access procedure.

[0071] The disclosure herein also discusses triggering mechanisms, reference signal configurations, reporting volume considerations, and timeline constraints for supporting early CSI reporting during a RACH procedure.

[0072] Triggering mechanism for the 4-step PRACH process

[0073] For the 4-step PRACH process, CSI can be reported in Msg3.

[0074] To trigger the reporting of CSI in Msg3 for the 4-step PRACH procedure, there may be several different triggering mechanisms.

[0075] In some embodiments, to address backward compatibility issues, the reserved “CSI Request” field (e.g., Figure 4B If the "CSI request" field in the UL grant is not used, the gNB can inform the UE that the "CSI request" field in the UL grant is no longer reserved. The gNB can provide this information in the system information (SI) or RRC configuration.

[0076] A new field may be introduced in SI (more specifically, e.g., SIB1) to indicate to the UE that the reserved "CSI request" field in the UL grant provided in Msg2 (i.e., RAR message) is used. The UE may determine whether to report CSI in Msg3 based on the bit value in the "CSI request" field. For example, bit "0" may indicate that the UE should not report CSI in Msg3, while bit "1" may indicate that the UE should report CSI in Msg3.

[0077] In some other embodiments, the gNB may configure in the SI or RRC configuration whether the UE should report CSI in Msg3. A new field may be introduced in the SI or RRC configuration to indicate whether the UE should report CSI in Msg3. In this case, the UE determines whether to report CSI in Msg3 based solely on the received SI or RRC configuration, without further reference to the reserved "CSI Request" field in the UL grant in Msg2.

[0078] In some other embodiments, a new "CSI Request" field may be introduced in DCI format 1_0 with CRC scrambled by RA-RNTI in Type 1-PDCCH CSS (Physical Downlink Control Channel Common Search Space). The newly introduced "CSI Request" field may be used to trigger the UE to report CSI in Msg3.

[0079] The newly introduced "CSI Request" field may include 1 bit, where bit "0" indicates that the UE should not report CSI in Msg3, and bit "1" indicates that the UE should report CSI in Msg3.

[0080] The bit width of the newly introduced "CSI request" field may be greater than 1. In this case, the newly introduced "CSI request" field may also be used to indicate at least a portion of the CSI reporting configuration. For example, the newly introduced "CSI request" field may be used to indicate which CSI the UE should report.

[0081] In some other embodiments, the gNB may configure one or more PRACH resource pools associated with supporting early CSI reporting. Specifically, the gNB may configure different PRACH resource pools for UEs. For new UEs that support early CSI reporting, some PRACH resource pools may include PRACH resources that can be used with PUSCH that reports CSI in Msg3, while for legacy UEs that do not support early CSI reporting, other PRACH resource pools may include PRACH resources that can be used as a legacy approach (i.e., not reporting CSI in Msg3).

[0082] The gNB may transmit SI or RRC configuration including different PRACH resource pools to the UE. The UE supporting early CSI reporting selects / uses PRACH resources from the PRACH resource pool associated with supporting early CSI reporting. The UE may transmit communications (e.g., Msg1 including the selected PRACH preamble) to the gNB using the selected PRACH resources.

[0083] In this case, from the UE's perspective, the gNB provides a PRACH resource pool associated with supporting early CSI reporting to indicate to the UE that the network supports early CSI reporting during the RACH procedure. From the gNB's perspective, the UE's selection / use of PRACH resources from the PRACH resource pool associated with supporting early CSI reporting means that the UE supports early CSI reporting (e.g., in the case of reporting CSI in Mag3) or even that the UE has already reported CSI during the RACH procedure (e.g., in the case of reporting CSI in MsgA).

[0084] In case of reporting CSI in Msg3, the UE may determine to trigger CSI reporting, for example, based on SI or RRC configuration or a "CSI request" field in DCI format 1_0 or RARMAC CE, and then report CSI in Msg3.

[0085] In some other embodiments, a new MAC CE or a new DCI may be introduced to carry a CSI reporting trigger indication (eg, a "CSI Request" field) indicating whether the UE should report CSI in Msg3.

[0086] Triggering mechanism for 2-step PRACH process

[0087] For the 2-step PRACH process, CSI may be reported in MsgA.

[0088] In some embodiments, the gNB may configure in the SI or RRC configuration whether the UE should report CSI in Msg A. For example, a field comprising one or more bits may be introduced in the SI or RRC configuration to indicate whether the UE should report CSI during the RACH process.

[0089] In some embodiments, the SI or RRC configuration may also include a CSI reporting configuration, such as a reference signal configuration for CSI measurement and / or a reporting quantity configuration for CSI reporting.

[0090] Upon determining to report CSI in MsgA based on the received SI or RRC configuration, the UE may perform CSI measurement and CSI reporting based on the CSI reporting configuration.

[0091] In some other embodiments, the gNB may configure PRACH resource pools associated with supporting early CSI reporting. Specifically, the gNB may configure different PRACH resource pools for UEs. For new UEs that support early CSI reporting, some PRACH resource pools may include PRACH resources that can be used with PUSCH that reports CSI in MsgA, while for legacy UEs that do not support early CSI reporting, other PRACH resource pools may include PRACH resources that can be used as a legacy approach (i.e., not reporting CSI in MsgA).

[0092] The gNB may transmit SI or RRC configuration including different PRACH resource pools to the UE. The UE supporting early CSI reporting selects / uses PRACH resources from the PRACH resource pool associated with supporting early CSI reporting and reports CSI in MsgA.

[0093] In this case, from the UE's perspective, the gNB provides a PRACH resource pool associated with supporting early CSI reporting to indicate to the UE that the network supports early CSI reporting during the RACH procedure. From the gNB's perspective, the UE's selection / use of PRACH resources from the PRACH resource pool associated with supporting early CSI reporting means that the UE supports early CSI reporting and can report CSI (including PRACH preamble and data) in MsgA.

[0094] Triggering mechanism for 2-step PRACH process during fallback operation

[0095] For the 2-step PRACH process during fallback operation, CSI may be reported in Msg3. The triggering mechanism for fallback operation may be similar to that for the 4-step PRACH process.

[0096] In some embodiments, to address the backward compatibility issue, i.e., the reserved "CSI Request" field in the UL grant provided in the fallback RAR message (which may contain the same information as the RAR for 4-step RACH) is useless, the gNB may inform the UE that the "CSI Request" is no longer reserved in, for example, the System Information (SI) or RRC configuration.

[0097] A new field may be introduced in SI (more specifically, e.g., SIB1) to indicate to the UE that the reserved "CSI request" field in the UL grant provided in the fallback RAR message is used. The UE may determine whether to report CSI in Msg3 based on the bit value in the "CSI request" field in the UL grant. For example, bit "0" may indicate that the UE should not report CSI in Msg3, while bit "1" may indicate that the UE should report CSI in Msg3.

[0098] In some other embodiments, the gNB may configure in the SI or RRC configuration whether the UE should report CSI in Msg3. One or more bits may be introduced in the SI or RRC configuration to indicate whether the UE should report CSI in Msg3. In this case, the UE determines whether to report CSI in Msg3 based solely on the received SI or RRC configuration, without further reference to the reserved "CSI Request" field in the UL grant provided in the fallback RAR message.

[0099] In some other embodiments, a new "CSI Request" field may be introduced in DCI format 1_0 with CRC scrambled by MsgB-RNTI in Type 1-PDCCH CSS. When the UE detects fallback RAR MAC-CE, the newly introduced "CSI Request" field may trigger the UE to report CSI in Msg3.

[0100] The newly introduced "CSI Request" field may include 1 bit, where bit "0" indicates that the UE should not report CSI in Msg3, and bit "1" indicates that the UE should report CSI in Msg3.

[0101] The bit width of the newly introduced "CSI request" field may be greater than 1. In this case, the newly introduced "CSI request" field may also be used to indicate at least a portion of the CSI reporting configuration. For example, the newly introduced "CSI request" field may be used to indicate which CSI the UE should report.

[0102] In some other embodiments, the gNB may configure PRACH resource pools associated with supporting early CSI reporting. Specifically, the gNB may configure different PRACH resource pools for UEs. For new UEs that support early CSI reporting, some PRACH resource pools may include PRACH resources that can be used with PUSCH that reports CSI in Msg3, while for legacy UEs that do not support early CSI reporting, other PRACH resource pools may include PRACH resources that can be used as a legacy approach (i.e., not reporting CSI in Msg3).

[0103] The gNB may transmit SI or RRC configuration including different PRACH resource pools to the UE. The UE supporting early CSI reporting selects / uses PRACH resources from the PRACH resource pool associated with supporting early CSI reporting. The UE may transmit communications (e.g., Msg1 including the selected PRACH preamble) to the gNB using the selected PRACH resources.

[0104] In this case, the UE may determine to trigger CSI reporting, for example, based on SI or RRC configuration or the "CSI Request" field in DCI format 1_0 or fallback RAR MAC CE, and then report SCI in Msg3.

[0105] In some other embodiments, a new MAC CE or DCI may be introduced to carry a CSI reporting trigger indication (eg, a "CSI Request" field) indicating whether the UE should report CSI in Msg3.

[0106] Reference signal configuration

[0107] The reference signal used for CSI measurement may be any one of a synchronization signal and a PBCH block (SSB) or a channel state information reference signal (CSI-RS).

[0108] In some embodiments, for a 4-step RACH procedure or for fallback operation of a 2-step RACH procedure, the reference signal may be a reference signal (CSI-RS or SSB) used to initiate a PRACH transmission.

[0109] Figure 5A An example reference signal configuration according to embodiments disclosed herein is shown.

[0110] like Figure 5A As shown, the gNB uses SSBs as reference signals and transmits, for example, SSB1-SSB 4 in a burst, and the UE may measure SSBs 1-4 to try to find which one can be used to transmit PRACH. To reduce latency, the UE may transmit PRACH on SSB 2, assuming that it is first found to meet the quality requirements, even though SSB 3 may be the best if all SSBs 1-4 have been measured. After the UE transmits the PRACH associated with SSB 2 and before the UE transmits Msg 3, the UE may have completed measurements on all SSBs 1-4 and determined that SSB 3 is the best. Then in Msg 3, the UE will report to the gNB in ​​the CSI that SSB 3 is the best. In this case, the SSB burst (SSB 1-4) including SSB 2 that initiated the PRACH transmission will be used as the reference signal for CSI measurement.

[0111] Figure 5B Another example reference signal configuration according to embodiments disclosed herein is shown.

[0112] Assume that there is a long delay between PRACH (Msg 1) and Msg3. In this case, the UE may initially generate a CSI report based on the SSB burst that initiated the PRACH transmission, and then update the CSI report based on one or several latest observations of the same reference signal. That is, after the UE transmits Msg 1 and before the UE transmits Msg 3, the gNB may have transmitted multiple SSB bursts, for example every 20ms, and the UE has completed the measurement of the last SSB burst, and therefore it can report CSI in Msg3 based on the measurement of the last SSB burst or the measurement of the last few SSB bursts. Figure 5B As shown, the CSI reported in Msg3 can be generated or updated based on the last SSB burst. In this case, the last SSB burst or the last few SSB bursts can be used as a reference signal for CSI measurement.

[0113] In some other embodiments, a reference signal other than the reference signal used to initiate PRACH transmission may be configured separately for CSI measurement. The reference signal configuration may be performed in SI or RRC configuration.

[0114] For example, in addition to the reference signal used to initiate PRACH transmission, the gNB may configure different / additional reference signals for CSI measurements (e.g., for beam refinement).

[0115] In some embodiments, only SSB may be used. In other embodiments, both SSB and CSI-RS may be used, but they cannot be mixed for the same CSI report. In other embodiments, both SSB and CSI-RS may be used, and they may be mixed for the same CSI report.

[0116] In some embodiments, only periodic signals may be used. In other embodiments, both periodic and aperiodic signals may be used, but all reference signals used for the same CSI report should have the same time domain behavior. That is, all reference signals used for the same CSI report should be either periodic or aperiodic.

[0117] In some embodiments, only 1-port reference signals may be used. In other embodiments, both 1-port reference signals and 2-port reference signals may be used, but all reference signals for the same CSI report should have the same number of ports. In some embodiments, up to X-port (X>= 4) reference signals may be used, but all reference signals for the same CSI report should have the same number of ports. For example, for CSI-RS, up to 32 ports may be supported. 1-port reference signals may be used to measure beams. 2-port reference signals may be used to measure beams and multi-layer transmissions. Multi-port reference signals with 4 ports or more than 4 ports may be used to measure multiple-input multiple-output (MIMO) layers.

[0118] Report volume configuration

[0119] The reporting volume configuration includes which reporting parameters should be reported.

[0120] In some embodiments, when CSI can be reported in Msg3 or 2-step RACH or 2-step RACH fallback operation, the reporting quantity may include L1-RSRP. That is, the reporting quantity may include cri-RSRP or ssb-Index-RSRP, where cri-RSRP refers to the CSI-RS resource indicator / index.

[0121] In some other embodiments, the reported quantity may include L1-SINR, that is, the reported quantity may include cri-SINR-r16 or ssb-Index-SINR-r16.

[0122] In some other embodiments, the reported quantity may include one or more of cri-RI-PMI-CQI, cri-RI-LI-PMI-CQI, cri-RI-i1, cri-RI-i1-CQI or cri-RI-CQI, where RI refers to rank indicator, PMI refers to precoding matrix indicator, CQI refers to channel quality indicator, and L1 / i1 refers to layer indicator.

[0123] Those skilled in the art will appreciate that the reporting amount may include one or more of the reporting parameters described above, and may include any possible combination thereof.

[0124] In some embodiments, the reporting amount may be semi-statically configured by SI or RRC configuration. In some other embodiments, the reporting amount may be indicated by the "CSI Request" field in the DCI or UL grant (RAR MAC CE).

[0125] When reporting L1-RSRP or L1-SINR, the number of beams may be taken into account. In some embodiments, only 1 (best) beam will be reported. In some other embodiments, more than 1 beam may be reported, and the number of beams to be reported may be indicated by the "CSI Request" field in either the DCI or UL grant (RAR MAC CE), or semi-statically configured by SI / RRC configuration.

[0126] When reporting L1-RSRP or L1-SINR, it may be considered whether the report is group-based. A group may include one or more pairs of beams, each pair containing two beams that the UE may receive simultaneously. In some embodiments, group-based reporting is not supported. In some other embodiments, only group-based reporting is supported. In some other embodiments, switching between group-based reporting and non-group-based reporting is supported, which may be indicated by the "CSI Request" field in either the DCI or UL grant (RAR MAC CE), or may be semi-statically configured by SI or RRC configuration.

[0127] Timeline Constraints

[0128] CSI measurement and / or CSI reporting may be performed based on a timeline constraint. The considered timeline constraint may include at least a minimum time (hereinafter referred to as minimum time T1) required for the UE to measure CSI and generate a CSI report.

[0129] In some embodiments, the minimum time T1 may be a predetermined fixed value.

[0130] In some other embodiments, the minimum time T1 may be reported as the UE capability. Before establishing an RRC connection, the UE capability may be reported using different RACH resource pools. For example, in the case where a new PRACH resource pool associated with early CSI reporting is configured, from the gNB's perspective, the UE's use of PRACH resources from the new PRACH resource pool means that the UE's capability meets the timeline constraint based on the minimum time T1.

[0131] For the 2-step RACH procedure, the minimum time T1 required for the UE to measure CSI and generate a CSI report can be defined as the time from the start point to the end point, where the start point is the end of the last reference signal used for CSI measurement and the end point is the first symbol of the PUSCH carrying the CSI report.

[0132] For the 4-step RACH procedure or for the fallback operation of the 2-step RACH procedure, in addition to the minimum time T1, another minimum time (hereinafter referred to as minimum time T2) required for the UE to complete processing the CSI report trigger (e.g., the "CSI Request" field in the MAC CE or in the DCI) may also be considered.

[0133] The minimum time T2 may be defined as the time from the start point to the end point. The end point may be the first symbol of the PUSCH carrying the CSI report. The start point may be one of the following: (1) the last symbol of the DCI that triggers the CSI report in Msg3; (2) the last symbol of the PDSCH that carries the MAC-CE that triggers the CSI report in Msg3; or (3) 3 ms after the HARQ-ACK that responds to the PDSCH that carries the MAC-CE that triggers the CSI report in Msg3.

[0134] In addition to reference signal configuration and / or CSI reporting configuration, CSI measurement and / or CSI reporting may also be performed based on timeline constraints.

[0135] Figure 6 Example minimum timeline constraints for fallback operation for a 4-step RACH procedure or for a 2-step RACH procedure according to embodiments disclosed herein are shown.

[0136] like Figure 6 As shown, the time T1' is calculated from the starting point to the ending point, and the starting point is the end of the last reference signal used for CSI measurement (i.e., at Figure 6 The end point is the first symbol of the PUSCH in Msg 3 that carries the CSI report.

[0137] like Figure 6As shown, time T2' is calculated from the starting point to the ending point. The ending point may be the first symbol of the PUSCH in Msg 3 carrying the CSI report. The starting point may be one of the following: (1) the last symbol of the DCI in Msg 2 that triggers the CSI report in Msg3; (2) the last symbol of the PDSCH in Msg 2 that carries the MAC-CE that triggers the CSI report in Msg3; or (3) 3 ms after the HARQ-ACK in response to the PDSCH in Msg 2 that carries the MAC-CE that triggers the CSI report in Msg3.

[0138] For the UE, T1' and T2' should satisfy the timeline constraints including the minimum time T1 and the minimum time T2.

[0139] Figure 7 A method 700 performed by a UE according to embodiments disclosed herein is shown.

[0140] like Figure 7 As shown, method 700 includes operation 701, in which a UE reports CSI to a base station during a RACH procedure.

[0141] The UE may report CSI in Msg3 for a 4-step RACH procedure and in MsgA for a 2-step RACH procedure; or report CSI in Msg3 during fallback operation for a 2-step RACH procedure.

[0142] Figure 8 A method 800 performed by a base station according to embodiments disclosed herein is shown.

[0143] like Figure 8 As shown, method 800 includes operation 801, in which a base station receives CSI reported by a UE during a RACH procedure.

[0144] For the 2-step RACH procedure or for the 2-step RACH procedure during fallback operation, the CSI may be received in Msg3. For the 2-step RACH procedure, the base station may receive the CSI in MsgA.

[0145] Fig. 9 A method 900 performed by a UE according to an embodiment disclosed herein is shown.

[0146] like Fig. 9 As shown, method 900 includes operation 901, in which a UE receives a trigger for triggering reporting of CSI during a RACH process from a base station.

[0147] The trigger may be one or more bits that can be used to trigger the UE to perform early CSI reporting. For example, one bit with a value of "1" may be used as a trigger.

[0148] More specifically, the trigger may be used to indicate that the UE should report CSI in Msg3 for a 4-step RACH procedure or for a fallback operation of a 2-step RACH procedure, or report CSI in MsgA for a 2-step RACH procedure.

[0149] The trigger may be included in the system information (SI) or RRC configuration. One or more bits may be introduced into the SI or RRC configuration to indicate to the UE whether early CSI reporting is triggered. More specifically, the trigger included in the SI or RRC configuration indicates to the UE that the UE should report CSI in Msg3 for a 4-step RACH procedure or for a fallback operation of a 2-step RACH procedure, or report CSI in MsgA for a 2-step RACH procedure.

[0150] The trigger may be included in the MAC CE.

[0151] In some embodiments, the previously inverted "CSI Request" field in the RAR MAC CE (UL Grant) may be used to indicate whether early CSI reporting should be performed. For example, if the previously inverted "CSI Request" field includes a bit 1, it indicates that the UE should report CSI during the RACH procedure. In this case, a bit may be introduced in the SI or RRC configuration so that the previously inverted "CSI Request" field is no longer reserved, and a bit "1" in the "CSI Request" field may be used as a trigger to trigger early CSI reporting at the UE.

[0152] In some other embodiments, the trigger may be included in a newly introduced MAC CE.

[0153] The trigger may be included in the DCI. The new "CSI Request" field introduced into DCI format 1_0 may be used to indicate whether early CSI reporting should be performed. For example, if the new "CSI Request" field includes bit 1, it indicates that the UE should report CSI during the RACH process. In some embodiments, more than one bit may be set in the new "CSI Request" field to allow dynamic selection of the CSI to be reported.

[0154] In some other embodiments, the trigger may be included in the newly introduced DCI.

[0155] Method 900 includes operation 902, in which the UE reports CSI to a base station during a RACH procedure.

[0156] Operation 902 is similar to Figure 7 Therefore, detailed description of operation 902 is omitted.

[0157] Fig.10 A method 1000 performed by a base station according to embodiments disclosed herein is shown.

[0158] like Fig.10 As shown, method 1000 includes operation 1001, in which a base station transmits a trigger for triggering reporting of CSI during a RACH process to a UE.

[0159] The method 1000 also includes operation 1002, in which the base station receives CSI reported by the UE during a RACH procedure.

[0160] Fig.11 A method 1100 performed by a UE according to an embodiment disclosed herein is shown.

[0161] like Fig.11 As shown, method 1100 includes operation 1101, in which a UE receives a trigger for triggering reporting of CSI during a RACH process from a base station.

[0162] The method 1100 also includes operation 1103 , in which the UE receives a CSI report configuration from the base station.

[0163] The CSI reporting configuration includes at least one of: (i) a reference signal configuration for CSI measurement, or (ii) a reporting quantity configuration for CSI reporting.

[0164] At least a portion of the CSI reporting configuration may be included in one of: (i) system information (SI) or RRC configuration; (ii) MAC CE; or (iii) DCI.

[0165] In some embodiments, the trigger and CSI reporting configuration are included in the SI or RRC configuration. In some embodiments, the trigger and CSI reporting configuration are included in the MAC CE or DCI, for example, in the "CSI request field".

[0166] The method 1100 also includes operation 1105 , in which the UE performs CSI measurement and CSI reporting based on the CSI reporting configuration.

[0167] Fig.12 A method 1200 performed by a base station according to embodiments disclosed herein is shown.

[0168] like Fig.12 As shown, method 1200 includes operation 1201, in which a base station transmits a trigger for triggering reporting of CSI during a RACH process to a UE.

[0169] The method 1200 also includes operation 1203, in which the UE transmits a CSI reporting configuration to the UE.

[0170] The base station may transmit the CSI reporting configuration in SI or RRC configuration, MAC CE or DCI.

[0171] The method 1200 also includes operation 1205, in which the base station receives CSI reported by the UE during the RACH process. The received CSI is obtained by the UE based on the CSI reporting configuration.

[0172] In some embodiments, for a 2-step RACH procedure, the UE may receive a PRACH resource configuration in an SI or RRC configuration from the base station. The PRACH resource configuration may include available PRACH resources from a PRACH resource pool associated with supporting reporting CSI during a RACH procedure. The UE may select a PRACH resource from the available PRACH resources and transmit an MsgA using the selected PRACH resources. The transmitted MsgA includes a CSI report and a selected PRACH preamble. In this case, from the perspective of the UE, the gNB configuration of available PRACH resources from a PRACH resource pool associated with supporting reporting CSI during a RACH procedure is an implicit trigger for early CSI reporting at the UE. From the perspective of the gNB, the UE uses a PRACH resource selected from the available PRACH resources to indicate that the MsgA sent by the UE may include an early CSI report. In this case, the CSI reporting configuration may be included in the SI or RRC configuration.

[0173] In some embodiments, for a 4-step RACH procedure or for a fallback operation of a 2-step RACH procedure, the UE may receive a PRACH resource configuration in an SI or RRC configuration from a base station, the PRACH resource configuration including available PRACH resources from a PRACH resource pool associated with supporting reporting CSI during a RACH procedure. The UE may select a PRACH resource from the available PRACH resources and transmit Msg1 by using the selected PRACH resource.

[0174] In this case, for example, the trigger and CSI report configuration may also be included in the SI or RRC configuration. However, as another example, the trigger and CSI report configuration may also be included in the MAC CE and / or DCI.

[0175] In some embodiments, timeline constraints are considered. CSI measurement and / or CSI reporting may be performed based on the timeline constraints.

[0176] The timeline constraint may include at least a first minimum time required for the UE to measure CSI and generate a CSI report. The first minimum time may be defined as the time from a start point to an end point, where the end point is the first symbol of the PUSCH carrying the CSI report and the start point is the end of the last reference signal used for CSI measurement.

[0177] In some cases, the timeline constraint also includes a second minimum time required for the UE to complete processing the trigger. The second minimum time can be defined as the time from the starting point to the end point, where the end point can be the first symbol of the PUSCH carrying the CSI report, and the starting point can be one of the following: (i) the last symbol of the DCI format 1_0 that triggers the reporting of CSI in Msg3; (ii) the last symbol of the PDSCH carrying the MAC-CE that triggers the reporting of CSI in Msg3; or (iii) 3ms after the HARQ-ACK that responds to the PDSCH carrying the MAC-CE that triggers the reporting of CSI in Msg3.

[0178] Embodiments contemplated herein include an apparatus including means for performing one or more elements of methods 700, 900, and 1100. The apparatus may be, for example, an apparatus of a UE (such as wireless device 202 as a UE, as described herein).

[0179] Embodiments contemplated herein include one or more non-transitory computer-readable media including instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of methods 700, 900, and 1100. The non-transitory computer-readable medium may be, for example, a memory of a UE (such as the memory 206 of the wireless device 202 as a UE, as described herein).

[0180] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry for performing one or more elements of methods 700, 900, and 1100. The apparatus may be, for example, an apparatus of a UE (such as wireless device 202 as a UE, as described herein).

[0181] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of methods 700, 900, and 1100. The apparatus may be, for example, an apparatus of a UE (such as wireless device 202 as a UE, as described herein).

[0182] Embodiments contemplated herein include a signal as described in or associated with one or more elements of methods 700 , 900 , and 1100 .

[0183] Embodiments contemplated herein include a computer program or computer program product including instructions, wherein execution of the program by a processor causes the processor to perform one or more elements of methods 700, 900, and 1100. The processor may be a processor of a UE (such as the processor 204 of the wireless device 202 as a UE, as described herein). These instructions may be located, for example, in a processor and / or on a memory of a UE (such as the memory 206 of the wireless device 202 as a UE, as described herein).

[0184] Embodiments contemplated herein include an apparatus comprising means for performing one or more elements of methods 800, 1000, or 1200. The apparatus may be, for example, an apparatus that is a base station (such as network device 218 that is a base station, as described herein).

[0185] Embodiments contemplated herein include one or more non-transitory computer-readable media including instructions that, when executed by one or more processors of an electronic device, cause the electronic device to perform one or more elements of methods 800, 1000, and 1200. The non-transitory computer-readable medium may be, for example, a memory of a base station (such as memory 222 of network device 218 as a base station, as described herein).

[0186] Embodiments contemplated herein include an apparatus comprising logic, modules, or circuitry for performing one or more elements of methods 800, 1000, and 1200. The apparatus may be, for example, an apparatus that is a base station (such as network device 218 as a base station, as described herein).

[0187] Embodiments contemplated herein include an apparatus comprising: one or more processors and one or more computer-readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform one or more elements of methods 800, 1000, or 1200. The apparatus may be, for example, an apparatus that is a base station (such as network device 218 that is a base station, as described herein).

[0188] Embodiments contemplated herein include a signal as described in or associated with one or more elements of methods 800 , 1000 , or 1200 .

[0189] Embodiments contemplated herein include a computer program or computer program product including instructions, wherein execution of the program by a processing element causes the processing element to perform one or more elements of methods 800, 1000, or 1200. The processor may be a processor of a base station (such as processor 220 of network device 218 as a base station, as described herein). These instructions may be located, for example, in the processor and / or on a memory of a UE (such as memory 222 of network device 218 as a base station, as described herein).

[0190] For one or more embodiments, at least one of the components set forth in one or more of the foregoing figures may be configured to perform one or more operations, techniques, processes and / or methods as set forth herein. For example, a baseband processor as described herein in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples set forth herein. For another example, circuits associated with a UE, a base station, a network element, etc. as described above in conjunction with one or more of the foregoing figures may be configured to operate according to one or more of the examples set forth herein.

[0191] Unless explicitly stated otherwise, any of the above embodiments may be combined with any other embodiment (or combination of embodiments). The foregoing description of one or more specific implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of the embodiments to the precise form disclosed. In view of the above teachings, modifications and variations are possible or can be obtained from the practice of various embodiments.

[0192] Embodiments and implementations of the systems and methods described herein may include various operations that may be embodied in machine executable instructions to be executed by a computer system. A computer system may include one or more general or special purpose computers (or other electronic devices). A computer system may include hardware components that include specific logic components for performing operations; or may include a combination of hardware, software, and / or firmware.

[0193] It should be appreciated that the systems described herein include descriptions of specific embodiments. These embodiments may be combined into a single system, partially combined into other systems, separated into multiple systems, or otherwise divided or combined. In addition, it is contemplated that parameters, attributes, aspects, etc. of another embodiment may be used in one embodiment. For clarity, these parameters, attributes, aspects, etc. are described only in one or more embodiments, and it should be appreciated that these parameters, attributes, aspects, etc. may be combined with or substituted for parameters, attributes, aspects, etc. of another embodiment unless expressly stated herein.

[0194] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

[0195] Although the foregoing has been described in considerable detail for the sake of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles of the invention. It should be noted that there are many alternative ways of implementing both the processes and the apparatus described herein. Therefore, the embodiments of the present invention should be regarded as illustrative rather than restrictive, and the specification is not limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Claims

1. A user equipment (UE), comprising: at least one antenna; at least one radio component coupled to the at least one antenna; and a processor coupled to the at least one radio; The UE is configured to perform the following operations: receiving, from a base station, a trigger for triggering reporting of CSI during a RACH procedure; as well as CSI is reported to the base station during the RACH procedure.

2. The UE according to claim 1, wherein reporting CSI to the base station during the RACH process further comprises one of the following: For the 4-step RACH process, CSI is reported in Msg3; For a 2-step RACH procedure, report CSI in MsgA; or For the 2-step RACH procedure, CSI is reported in Msg3 during fallback operation.

3. The UE according to claim 1, wherein the trigger is included in one of the following: (i) System Information (SI) or RRC configuration; (ii) MAC CE; or (iii) DCI.

4. The UE according to claim 1, wherein the operation further comprises: receiving, from the base station, a PRACH resource configuration in an SI or RRC configuration, the PRACH resource configuration comprising available PRACH resources from a PRACH resource pool associated with supporting reporting of CSI during a RACH procedure; as well as A communication is sent to the base station using a PRACH resource from the available PRACH resources.

5. The UE according to claim 1, wherein the operation further comprises: receiving a CSI reporting configuration from the base station, wherein the CSI reporting configuration includes at least one of: (i) a reference signal configuration for CSI measurement, or (ii) a reporting amount configuration for CSI reporting; and CSI measurement and CSI reporting are performed based on the CSI reporting configuration.

6. The UE according to claim 5, wherein at least a portion of the CSI reporting configuration is included in one of the following: (i) System Information (SI) or RRC configuration; (ii) MAC CE; or (iii) DCI. 7 . The UE according to claim 1 , wherein the reference signal used for CSI measurement is any one of SSB or CSI-RS.

8. The UE according to claim 1, wherein the reporting amount configuration for CSI reporting comprises at least one of the following: (i) L1-RSRP; (ii) L1-SINR; or (iii) cri-RI-PMI-CQI, cri-RI-LI-PMI-CQI, cri-RI-il, cri-RI-il-CQI or cri-RI-CQI.

9. The UE of claim 1, wherein the UE performs CSI measurement and CSI reporting during the RACH procedure based on a timeline constraint, wherein the timeline constraint comprises a first minimum time required for the UE to measure the CSI and generate a CSI report. 10 . The UE of claim 9 , wherein the timeline constraint further comprises a second minimum time required for the UE to complete processing the trigger for the CSI report.

11. A method comprising: By user equipment (UE), receiving, from a base station, a trigger for triggering reporting of CSI during a RACH procedure; as well as CSI is reported to the base station during the RACH procedure.

12. The method of claim 1, wherein reporting CSI to the base station during the RACH procedure further comprises one of: For the 4-step RACH process, CSI is reported in Msg3; For a 2-step RACH procedure, report CSI in MsgA; or For the 2-step RACH procedure, CSI is reported in Msg3 during fallback operation.

13. The method according to claim 1, Wherein the trigger is included in one of the following: (i) System Information (SI) or RRC configuration; (ii) MAC CE; or (iii) DCI.

14. An apparatus for operating a user equipment (UE), comprising: A processor, wherein the processor is configured to cause the UE to perform the method according to any one of claims 11 to 13.

15. A non-transitory computer-readable storage medium storing program instructions, which, when executed at a user equipment (UE), cause the UE to perform the method according to any one of claims 11 to 13.

16. A base station (BS), comprising: at least one antenna; at least one radio component coupled to the at least one antenna; as well as a processor coupled to the at least one radio; The BS is configured to perform the following operations: transmitting to a user equipment (UE) a trigger for triggering reporting of CSI during a RACH procedure; and receiving CSI reported by the UE during the RACH procedure.

17. The BS of claim 16, wherein receiving the CSI reported by the UE during the RACH procedure further comprises one of: Receive the CSI reported in Msg3 for the 4-step RACH procedure; Receive the CSI reported in MsgA for the 2-step RACH procedure; or Receive CSI reported in Msg3 during fallback operation for the 2-step RACH procedure.

18. The BS of claim 16, wherein the trigger is included in one of: (i) System Information (SI) or RRC configuration; (ii) MAC CE; or (iii) DCI.

19. The BS of claim 16, wherein the operations further comprise: transmitting, to the UE, a PRACH resource configuration in an SI or RRC configuration, the PRACH resource configuration comprising available PRACH resources from a PRACH resource pool associated with supporting reporting of CSI during a RACH procedure; as well as Communications transmitted from the UE are received using PRACH resources from the available PRACH resources.

20. The BS of claim 16, wherein the operations further comprise: transmitting a CSI reporting configuration to the UE, wherein the CSI reporting configuration comprises at least one of: (i) a reference signal configuration for CSI measurement; or (ii) a reporting quantity configuration for CSI reporting; The received CSI is obtained by the UE based on the CSI reporting configuration.

21. The BS of claim 16, wherein at least a portion of the CSI reporting configuration is included in one of: (i) System Information (SI) or RRC configuration; (ii) MAC CE; or (iii) DCI. 22 . The BS of claim 16 , wherein the reference signal used for CSI measurement is any one of SSB or CSI-RS.

23. The BS of claim 16, wherein a reporting amount configuration for CSI reporting comprises at least one of: (i) L1-RSRP; (ii) L1-SINR; or (iii) cri-RI-PMI-CQI, cri-RI-LI-PMI-CQI, cri-RI-il, cri-RI-il-CQI or cri-RI-CQI.

24. A method comprising: By base station (BS), transmitting to a user equipment (UE) a trigger for triggering reporting of CSI during a RACH procedure; as well as receiving CSI reported by the UE during the RACH procedure.

25. An apparatus for operating a base station (BS), comprising: A processor, wherein the processor is configured to cause the UE to perform the method according to claim 24.

26. A non-transitory computer-readable storage medium storing program instructions, which when executed at a base station (BS) cause the BS to perform the method of claim 24.

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