User equipment, base station and method thereof in a wireless communication system

Abstract

The disclosure relates to a fifth generation (5G) or pre-5G communication system to be implemented to support higher data rates beyond the fourth generation (4G) communication system such as long term evolution (LTE). According to various embodiments of the disclosure, a method for operating a base station in a wireless communication system is provided. The method includes generating remaining minimum system information (RMSI) including a random access channel (RACH) configuration, wherein the RACH configuration includes an association between a RACH resource and one of a synchronization signal (SS) block and a channel state information reference signal (CSI-RS) resource, and transmitting the RMSI to a user equipment (UE).

Description

[0001] This application is a divisional application of the invention patent application filed on May 3, 2018, with application number 201880029946.7 and entitled "Apparatus and method for managing random access channel configuration in a wireless communication system". Background Technology

[0002] This disclosure relates to wireless communication systems, and more specifically, to methods and systems for managing the configuration of random access channels (RACH) in wireless communication systems.

[0003] To meet the increased demand for wireless data services since the deployment of fourth-generation (4G) communication systems, efforts have been made to develop improved fifth-generation (5G) or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-LTE systems".

[0004] The implementation of 5G communication systems in higher frequency (mmWave) bands (e.g., 28 GHz or 60 GHz bands) is considered to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO, full-size MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies are discussed in 5G communication systems.

[0005] In addition, in 5G communication systems, the development of system network improvements is based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP) receiver interference cancellation, etc.

[0006] In 5G systems, hybrid frequency shift keying (FSK), quadrature amplitude modulation (QAM) (FQAM), and sliding window superposition coding (SWSC) have been developed as advanced coding modulation (ACM), as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced access technologies.

[0007] For 5G communication systems, the frequency band above 6 GHz represents a potential spectrum for both data and voice communication services. In such bands, beamforming has been shown to be essential for successful communication. In this context, random access procedures are performed to facilitate communication between the user equipment (UE) and the base station.

[0008] The main objective of the embodiments described herein is to provide a method and system for managing RACH configuration in a wireless communication system. Summary of the Invention

[0009] Technical solution

[0010] According to various embodiments of this disclosure, a method for operating a base station in a wireless communication system is provided. The method includes: generating Residual Minimum System Information (RMSI) including a Random Access Channel (RACH) configuration, wherein the RACH configuration includes an association between RACH resources and one of a Synchronization Signal (SS) block and a Channel State Information Reference Signal (CSI-RS) resource; and transmitting the RMSI to a User Equipment (UE).

[0011] According to various embodiments of this disclosure, a method for operating a user equipment (UE) in a wireless communication system is provided. The method includes: receiving from a base station residual minimum system information (RMSI) including a random access channel (RACH) configuration, wherein the RACH configuration includes an association between RACH resources and one of a synchronization signal (SS) block and a channel state information reference signal (CSI-RS) resource; and performing a random access procedure based on the association.

[0012] According to various embodiments of this disclosure, a user equipment (UE) for a wireless communication system is provided. The apparatus includes: a transceiver; and at least one processor coupled to the transceiver and configured to: receive from a base station residual minimum system information (RMSI) including a random access channel (RACH) configuration, wherein the RACH configuration includes an association between RACH resources and one of a synchronization signal (SS) block and a channel state information reference signal (CSI-RS) resource; and perform a random access procedure based on the association.

[0013] These and other aspects of the embodiments herein will be better understood and appreciated when considered in conjunction with the following description and accompanying drawings. However, it should be understood that while the following description indicates preferred embodiments and their numerous specific details, it is illustrative and not restrictive. Many changes and modifications can be made within the scope of the embodiments herein without departing from the spirit of the invention, and the embodiments herein encompass all such modifications.

[0014] Before proceeding with the detailed description below, it may be advantageous to clarify the definitions of specific words and phrases used throughout the patent document: the terms “comprising” and “including” and their derivatives mean including but not limited to; the term “or” is inclusive, meaning and / or; the phrases “associated with” and “associated with” and their derivatives mean including, including, interconnected with, containing, contained within, connected to or connected with, coupled to or coupled with, communicate with, cooperate with, intertwine, juxtapose, proximate, bound to or bound with, have, have the property of, relating to, etc.; and the term “controller” means any device, system or part thereof that controls at least one operation, such device may be implemented by hardware, firmware or software or a combination of at least two of them. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether local or remote.

[0015] Furthermore, the various functions described below can be implemented or supported by one or more computer programs, each computer program being formed by computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or portions thereof suitable for implementation in 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 storage. "Non-transitory" computer-readable media does not include wired, wireless, optical, or other communication links that transmit transient electrical or other signals. Non-transitory computer-readable media includes media that can permanently store data and media that can store data and later rewrite it, such as rewritable optical discs or erasable memory devices.

[0016] This patent document provides definitions for other specific words and phrases, and those skilled in the art should understand that, in many cases (if not most), such definitions apply to the prior and future use of the words and phrases defined herein. Attached Figure Description

[0017] To gain a more complete understanding of this disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which the same reference numerals denote the same parts:

[0018] Figure 1 An example RACH process for beamforming in a 5G communication system is shown according to the prior art;

[0019] Figure 2 A block diagram of a wireless communication system in which a base station communicates with a UE according to embodiments disclosed herein is shown;

[0020] Figure 3 A flowchart illustrating various operations for performing a random access procedure based on the association between RACH resources and at least one of SS blocks and CSI-RS resources, according to embodiments disclosed herein;

[0021] Figure 4 An example scenario is shown where all MIB / SIB messages according to embodiments disclosed herein carry the same information about association;

[0022] Figure 5 Example scenarios are shown where each MIB / SIB message carries different information about the association, according to embodiments disclosed herein;

[0023] Figure 6 An example scenario is shown where a RACH burst is sent in one or more consecutive RACH moments according to embodiments disclosed herein;

[0024] Figure 7 An example scenario is shown where RACH resources are numbered according to a frequency-based mapping, according to embodiments disclosed herein;

[0025] Figure 8 An example scenario illustrating a random association between SS blocks and RACH resources according to embodiments disclosed herein;

[0026] Figure 9 An example scenario illustrating the association between an SS block and a RACH resource according to embodiments disclosed herein;

[0027] Figure 10 An example scenario illustrating the association between an SS block and a RACH resource according to embodiments disclosed herein;

[0028] Figure 11 An example scenario illustrating the association between an SS block and a RACH resource according to embodiments disclosed herein;

[0029] Figure 12 A flowchart illustrating various operations for performing a random access procedure for handover RACH based on the association between RACH resources and at least one of a plurality of SS blocks and a plurality of CSI-RS resources, according to embodiments disclosed herein;

[0030] Figures 13a and 13b illustrate a schematic diagram of the association between CSI-RS resources and RACH resources based on the QCL relationship between CSI-RS resources and SS blocks according to embodiments disclosed herein;

[0031] Figure 14a illustrates a schematic diagram of the association between CSI-RS resources and RACH resources based on the CSI-RS index of all CSI-RS resources in sequential order, according to an embodiment disclosed herein.

[0032] Figure 14b illustrates a schematic diagram of the association between CSI-RS resources and RACH resources in sequence order of a CSI-RS index based on switched RACH according to an embodiment disclosed herein;

[0033] Figure 15 Flowcharts illustrating various operations for calculating PRACH power levels according to embodiments disclosed herein; and

[0034] Figure 16 and Figure 17 A flowchart illustrating various operations for controlling PRACH power levels based on waveforms and parameter sets (numerology) according to embodiments disclosed herein is provided. Detailed Implementation

[0035] The following discussion Figures 1 to 17 The various embodiments used to describe the principles of this disclosure in this patent document are merely exemplary and should not be construed in any way as limiting the scope of this disclosure. Those skilled in the art will understand that the principles of this disclosure can be implemented in any suitably arranged system or device.

[0036] Various embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. In the following description, only specific details such as detailed configurations and components are provided to aid in an overall understanding of these embodiments of the present disclosure. Therefore, it will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Furthermore, for clarity and brevity, descriptions of well-known functions and constructions have been omitted.

[0037] Furthermore, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments may be combined with one or more other embodiments to form new embodiments. Throughout this document, unless otherwise stated, the term "or" means non-exclusive or. The examples used herein are intended only to facilitate an understanding of how the embodiments described herein can be practiced, and further to enable those skilled in the art to practice the embodiments described herein. Therefore, the examples should not be construed as limiting the scope of the embodiments described herein.

[0038] As is conventional in the art, embodiments can be described and illustrated in blocks that perform one or more described functions. These blocks, referred to herein as managers, engines, controllers, units, or modules, are physically implemented by analog and / or digital circuitry (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuitry, etc.) and may optionally be driven by firmware and software. The circuitry may, for example, be embodied in one or more semiconductor chips or on a substrate support such as a printed circuit board. The circuitry constituting the blocks can be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware performing some functions of the blocks and a processor performing other functions of the blocks. Without departing from the scope of this disclosure, each block of an embodiment may be physically divided into two or more interacting and discrete blocks. Similarly, without departing from the scope of this disclosure, the blocks of an embodiment may be physically combined into more complex blocks.

[0039] In the following description of various embodiments of this disclosure, hardware methods will be used as examples. However, various embodiments of this disclosure include techniques using both hardware and software; therefore, various embodiments of this disclosure may not exclude a software perspective.

[0040] The terms used in the following description concerning signals, channels, control information, network entities, and device elements are for convenience only. Therefore, this disclosure is not limited to the following terms, and other terms with the same technical meaning may be used.

[0041] Furthermore, although this disclosure describes various embodiments based on terminology used in some communication standards (e.g., the 3rd Generation Partnership Project (3GPP)), these communication standards are merely examples for the purpose of description. The various embodiments of this disclosure can be readily modified and applied to other communication systems.

[0042] The term "NR" stands for "new radio," a term used in 3GPP specifications to discuss activities related to 5G communication systems.

[0043] Without departing from the scope of the embodiments, the terms "base station" and "gNB" as used herein are used interchangeably. Furthermore, without departing from the scope of the embodiments, the terms "mapping" and "association" as used herein are used interchangeably. Without departing from the scope of the embodiments, the terms "Msg1" and "RACH message 1" as used herein are used interchangeably. Without departing from the scope of the embodiments, the terms "Msg2" and "RACH message 2" as used herein are used interchangeably. Without departing from the scope of the embodiments, the terms "Msg3" and "RACH message 3" as used herein are used interchangeably. Without departing from the scope of the embodiments, the terms "Msg4" and "RACH message 4" as used herein are used interchangeably.

[0044] Typically, mobile communication systems have been developed to provide users with high-quality mobile communication services. With the rapid development of communication technology, mobile communication systems are now capable of providing high-speed data communication services as well as voice communication services. Long Term Evolution (LTE) is a technology used to implement packet-based communication at a higher data rate of approximately 100 Mbps. To meet the increasing demand for wireless data services, efforts have been made to develop improved fifth-generation (5G) communication systems, or LTE-Advanced communication systems, since the deployment of fourth-generation (4G) communication systems. Therefore, 5G or LTE-Advanced communication systems are also referred to as "super 4G networks" or "post-LTE systems." 4G communication systems operate in the spectrum band below 6 GHz, with all transmissions and receptions in an omnidirectional manner. 5G communication systems are also considered to be implemented in higher frequency (millimeter wave) bands, such as 28 GHz and 60 GHz, to achieve higher data rates.

[0045] For 5G communication systems, frequency bands above 6 GHz represent a potential spectrum for both data and voice communication services. Beamforming has been shown to be essential for successful communication within such bands. In this context, random access procedures are performed to facilitate communication between the user equipment (UE) and the base station.

[0046] The random access procedure is the most basic process performed by the UE to gain access to the network (eNodeB) after downlink synchronization. Without this random access procedure, the UE will not be able to obtain timing alignment for its uplink transmissions, and without timing alignment, the eNodeB will not be able to decode the UL. Furthermore, as a user moves from one location to another, the user's UE continues to perform handovers from one base station to another. In this case, the inter-cell measurement procedures may be modified for beamforming, thus potentially requiring consideration of a successful random access procedure.

[0047] In LTE systems, the UE performs an initial access procedure by scanning the Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS), and then synchronizes with the downlink. After synchronization, the UE performs a random access procedure to obtain uplink synchronization for appropriate uplink transmission. This is typically a contention-based process, where the UE must compete with several other users to be successfully heard by the base station. Alternatively, there is another procedure for random access called a contention-free random access procedure, where the UE is provided with dedicated resources for sending a random access preamble to the base station for uplink synchronization. In this case, the contention-free random access procedure is more suitable during inter-base station handover. In this scenario, the UE needs uplink synchronization with the target base station for seamless connectivity when handing over from the source base station to the target base station. To this end, the target base station allocates dedicated resources (which can be time-domain / frequency-domain / code-domain resources) to the UE, and the UE sends the random access preamble on these dedicated resources. This minimizes the latency involved in the contention-free random access procedure.

[0048] Figure 1 This illustrates an example of a beamforming-based Random Access Channel (RACH) procedure in a 5G communication system. The RACH procedure is performed after the downlink (DL) synchronization phase. The UE performs the RACH procedure using either a Transmit / Receive Point (TRP) within a cell area controlled by the 5G communication system or the gNB itself. Since the optimal beam is unknown during the initial access RACH procedure, a beam-scanning-based mechanism is required during this phase. However, performing this procedure during handover from the source base station (gNB) to the target base station (gNB) can be slow. Therefore, additional mechanisms are needed to improve this mechanism. However, this mechanism depends on how inter-gNB measurements are performed.

[0049] For a UE connected to a source gNB, the UE has an optimal beam pair. After receiving a handover request from the source gNB, the UE must perform measurements on neighboring cells. Since the optimal beam is unknown in this case, the UE must scan all possible directions to find the inter-cell measurement results. Inter-cell measurements for 5G are described below:

[0050] Based on synchronization signals (SS blocks); and

[0051] Channel State Information Reference Signal (CSI-RS).

[0052] In the SS block-based approach, all ports of the target gNB simultaneously transmit the same SS signal in the relevant direction. For example, all beams adjacent to each other can form a relevant beam. In this way, although the beam from each port is narrow, the overall effect of transmitting the same SS signal along the relevant direction produces a wider beam. Unlike option (a), option (b) relies solely on a narrow beam formed using CSI-RS. In other words, all ports of the target gNB transmit SS signals and CSI-RS in different directions at a given time. In this case, the UE can only see one beam in a specific direction.

[0053] For 5G communication systems, the beamforming-based random access procedure based on multi-stage contention has been solved. However, the contention-free random access procedure required for handover and timing alignment adjustments in 5G communication systems remains to be solved.

[0054] Therefore, it is desirable to address the aforementioned or other shortcomings, or at least provide a useful alternative.

[0055] The main objective of the embodiments described herein is to provide a method and system for managing RACH configuration in a wireless communication system.

[0056] Another objective of this embodiment is for the base station to configure the remaining minimum system information (RMSI) information, which includes RACH configuration, wherein the RACH configuration includes the association between RACH resources and one of the SS blocks and CSI-RS resources.

[0057] Another objective of this embodiment is to configure a common RACH configuration among all SS blocks.

[0058] Another objective of this embodiment is to configure a portion of the common RACH configuration among all SS blocks.

[0059] Another objective of this embodiment is to configure different RACH configurations between different SS blocks.

[0060] Another objective of this embodiment is to broadcast the complete RACH configuration in all SS blocks used for RMSI within the cell.

[0061] Another objective of this embodiment is for the base station to indicate the RMSI to the UE.

[0062] Another objective of this embodiment is to indicate to the UE multiple bits for RACH configuration in the RMSI using at least one of the RMSI, the Physical Downlink Control Channel (PDCCH) RMSI, and the Physical Broadcast Channel (PBCH).

[0063] Another objective of this embodiment is to use the PDCCH RMSI to indicate to the UE the location of multiple bits used for RACH configuration in the RMSI Physical Downlink Shared Channel (PDSCH).

[0064] Another objective of this embodiment is for the UE to perform a random access procedure based on association.

[0065] Another objective of this embodiment is to use at least one of RMSI, PDCCH RMSI and Physical Broadcast Channel (PBCH) to decode multiple bits from the base station for RACH configuration in RMSI.

[0066] Another objective of the embodiments described herein is to decode the RACH configuration in the RMSI from the most significant bit (MSB) or the least significant bit (LSB) of a plurality of bits.

[0067] Another objective of this embodiment is to configure the association between RACH resources and multiple SS blocks and multiple CSI-RS resources by the base station.

[0068] Another objective of this embodiment is for the base station to indicate the association for switching RACH to the UE.

[0069] Another objective of this embodiment is for the UE to perform a random access procedure for switching RACH based on association.

[0070] Another objective of this embodiment is to indicate the parameter set of at least one of RACH message 1, RACH message 2, RACH message 3 and RACH message 4 in the RACH configuration in RMSI.

[0071] This document provides a method for managing RACH configuration in a wireless communication system. The method includes configuring RMSI information by a base station, wherein the RMSI information includes RACH configuration, which includes an association between RACH resources and one of SS blocks and CSI-RS resources. Furthermore, the method includes indicating the RMSI to the UE by the base station.

[0072] This document provides a method for managing RACH configuration in a wireless communication system. The method includes configuring associations between RACH resources and at least one of multiple SS blocks and multiple CSI-RS resources by a base station. Furthermore, the method includes instructing the UE (User Equipment) of the associations for RACH handover.

[0073] Unlike conventional methods and systems, the provided method can be used for random access procedures and configurations based on beamforming-based connection mode switching. The provided method allows the UE to receive RACH configuration within the RMSI. Furthermore, the provided method can be used to configure the RMSI in a beam-common manner, thus eliminating the need for the UE to decode the RMSI during beam changes, resulting in efficient power savings. Additionally, the provided method can be used to indicate multiple bits for RACH configuration to the UE. The provided method provides retransmission of the random access preamble necessary for a successful random access procedure.

[0074] The provided method allows a base station to associate RACH resources with one of the SS block and Channel State Information Reference Signal (CSI-RS) resources based on an explicit mapping and / or equation based on the initial access RACH mapping.

[0075] The provided method allows a base station to associate RACH resources with at least one of multiple SS blocks and multiple CSI-RS resources based on the QCL relationship between CSI-RS resources and SS block resources for contention-free RACH.

[0076] The methods presented herein are applicable to any future wireless technology that can be built on beamforming-based systems. It should be noted that, regardless of the exact signals used (i.e., SS blocks and CSI-RS), the embodiments in the provided methods and systems are applicable to all situations using wide and / or narrow beams.

[0077] Referring now to the accompanying drawings, more specifically to the preferred embodiments shown Figures 2 to 17 .

[0078] Figure 1 An example RACH process for beamforming in a 5G communication system is shown, based on existing technology.

[0079] like Figure 1As shown, the RACH procedure performed in this paper follows the downlink (DL) synchronization phase. This paper describes various RACH aspects and configurations for 5G and future wireless systems (beyond 5G). For Msg1 (such as preamble) retransmission, it can be supported on a slot-based basis instead of a subframe-based basis as in LTE systems. Furthermore, if a Random Access Response (RAR) is received in slot n, and the corresponding PDSCH does not contain a response to the preamble sent by the UE, the UE can be configured to send a new preamble during one of the following RACH slots upon request from a higher layer. This differs from the five-subframe delay in LTE and is necessary because once the UE discovers Msg1 on another SS block, it can send Msg1 on that other SS block. Similarly, if no RAR is obtained in slot n (configured by RAR timeline) of Msg1 transmitted by the UE, where slot n is the last slot of the RAR window (or, if the RAR window is configured by symbol, n can be considered at the symbol granularity), then, upon request from a higher layer, the UE can be configured to transmit a new Msg1 during one of the following RACH slots, with a different four subframe delay than configured in the LTE system. For example, for Msg1, if the UE finds a suitable SS block, the retransmission can begin in the next slot / symbol and RACH resources can be used.

[0080] RACH for Carrier Aggregation (CA) and Dual Connectivity: In LTE systems, random access procedures can be performed in both the primary cell (P-Cell) and the secondary cell (S-Cell). In the case of an S-Cell (excluding PS cells), only contention-free random access procedures (such as RAR handover RACH) are performed. Random access procedures in S-Cells (excluding PS-Cells) are initiated solely by the base station via PDCCH commands. PDCCH commands can be received in the same S-Cell (non-cross-carrier scheduling) or in a scheduling cell (cross-carrier scheduling). This process facilitates the establishment of timing advance (TA) for secondary timing advance groups (s TAGs).

[0081] When performing a random access procedure on the P-Cell while configuring CA, the UE sends a RACH preamble (Msg1) on the P-Cell and receives the corresponding RAR on the P-Cell. When performing a contention-free random access procedure on the S-Cell while configuring CA, the UE sends a RACH preamble on the S-Cell and receives the corresponding RAR on the P-Cell. In CA, only one RA procedure is performed at any given time, which helps reduce additional blind decoding on the S-Cell. For the primary timing advance group (pTAG), the UE can be configured to use the P-Cell as a timing reference. The TAG containing the P-Cell is the pTAG. When the S-Cell is deactivated, any ongoing random access procedure on the S-Cell is canceled. Compared to the RA procedure on the P-Cell, after sending the maximum number of PRACH preambles on the S-Cell, the UE cannot indicate an RA problem to the upper layers, but simply considers the RA procedure unsuccessful. The timing alignment values ​​can be used for PUCCH / PUSCH and probe reference signal (SRS) on P-cell / PS-Cell, and for PUSCH / SRS on S-Cell.

[0082] Furthermore, when performing a random access procedure on a P-Cell or PS-Cell while configuring dual connectivity (DC), the UE transmits a RACH preamble and receives a RAR on the corresponding cell. This is to ensure that unnecessary delays between the primary eNB (MeNB) and secondary eNB (SeNB) due to backhaul issues are avoided. Therefore, there is an advantage to supporting parallel RA procedures. When performing a contention-free random access procedure on an S-Cell (excluding PS-Cell) while configuring DC, the UE transmits a RACH preamble on the S-Cell and receives the corresponding RAR on the P-Cell for the primary cell group (MCG) and the PS-Cell for the secondary cell group (SCG). Similar to CA, this procedure helps reduce the number of blind decodings by avoiding blind decoding of the RACH on the S-Cell.

[0083] Since the new radio (NR) supports CA and DC, the above principles in NR are used as a baseline (excluding LTE-NR or NR-NR dual connectivity). The above mechanism of S-Cell can help avoid the configuration of the control resource set (CORESET) for RACH purposes. Furthermore, based on the above configuration and before the RACH process can be initiated, it is assumed that the following information about the cell is available: RACH transmission timing set, random access preamble set, power boost factor, maximum repetition count, and RAR window start, etc.

[0084] Impact of S-cell parameter set: S-cells can use a different parameter set compared to P-cells or PS-cells in NR. In this case, when receiving a RAR on a P-cell / PS-cell for a contention-free RA initiated by a PDCCH command, and containing initial UL authorization for handover situations (e.g.), assignment can be based on the S-cell parameter set. Since UL authorization may depend on the RB size, and thus on the parameter set used on the S-cell, this can affect the RAR format. The parameter set can be indicated in the RAR, or a default parameter set can be assumed for the S-cell and then used in the RAR, with appropriate RBG scaling. In the specification, the default parameter set of the S-cell can be fixed, or it can be associated with the synchronization signals received in the S-cell or the synchronization signals transmitted in the S-cell that the user first needs to synchronize, or the functionality of PBCH or RMSI.

[0085] TA value calculation based on parameter set: In the case of LTE, there is only one parameter set, and all TA calculations are performed based on a sampling time (Ts) that is fixed at (1 / 30720) ms. Therefore, considering the TA value calculated above, there is no ambiguity in TAG formation. However, in the case of NR, it is possible to support multiple parameter sets within and between operators. Therefore, the value of Ts can change based on the parameter set. In this case, the TA value indicated by RAR can be carefully signaled to the user, and when forming the TAG, the TAG can be based on the absolute TA value, rather than on the value of Ts (which depends on the parameter set). Otherwise, some reference parameter sets need to be configured to define the TA value calculation, and then all TAs can be calculated based on these. In addition, since it is possible to avoid unnecessarily increasing the number of TAGs and the size of the TAG ID field, it is possible to avoid having a TAG for each parameter set. However, if the process is simplified, a TAG for each parameter set can be used, and some signaling based on each such group can be used. For example, the TAG for each parameter set also depends on the UE capability.

[0086] For synchronous DC deployments, similar to LTE, power limits for the parallel RA process can be followed. In asynchronous deployments, power limits for the parallel RA process can be calculated based on certain priority rules determined by network configuration (e.g., data type). For example, Ultra-Reliable Low-Latency Communication (URLLC) can be given higher priority, regardless of whether it's a P-cell or S-cell. For LTE, in both synchronous and asynchronous DC deployments, for each cell group, the UE is configured with a minimum power as a percentage of its maximum UE output power Pcmax. Once the minimum power is assigned to each group, the remaining power can be shared based on network configuration priorities or based on which cell group started transmission earlier. Furthermore, the same concept applies to PRACH. And the same concept is used for LTE-NR dual connectivity and PRACH transmission.

[0087] However, NR supports multiple parameter sets, such as 1.25kHz, 5kHz…480kHz, etc., while LTE only uses 1.25kHz. Then, there are some differences in power calculation based on the subcarrier spacing used for power calculation in dual-connectivity mode. In this case, assuming that transmission power is maintained during transmissions with higher SCS, transmissions with lower SCS will limit UL power sharing.

[0088] Furthermore, there are differences in power calculations when NR uses CP-OFDM for RACH and LTE uses PRFT-s-OFDM for PRACH. Power sharing based on waveform may then be due to the higher PAPR of CP-OFDM compared to PRFT-s-OFDM. Other waveforms can also be used for NR, such as pi / 2BPSK. Each of these can then have a separate backoff value based on the waveform. Accordingly, the UE power level can then be indicated based on the waveform of the simultaneous RACH. For example, the following formula is given in equation (1),

[0089] PPRACH=min{P CMAX, c,PREAMBLE_RECEIVED_TARGET_POWER+

[0090] PLc}----(1)

[0091] Where PREAMBLE_RECEIVED_TARGET_POWER = Preamble Initial Received Target Power + DELTA_PREAMBLE + (PREAMBLE_TRANSMISSION_COUNTER – 1) * Power Boost Step Size

[0092] The initial receive target power of the preamble, or DELTA_PREAMBLE, or the power boost step size, or Pcmax, can be changed based on the waveform used simultaneously. This can be configured by higher layers. These values ​​can be, for example, a 3dB difference between CP-OFDM and DFT-s-OFDM to indicate the backoff level. Furthermore, LTE uses DFT-s-OFDM, but NR can use CP-OFDM or DFT-s-OFDM or pi / 2BPSK with spectral shaping or other waveforms. Even within DFT-s-OFDM that depends on clustered or non-clustered transmission, the power level may change. Depending on the backoff level, the gap between single-clustered and multi-clustered DFT-s-OFDM can be ~1dB. For NR-NR dual connectivity, parameter sets, waveforms, beamforming effects, beamwidth, and other relevant parameters can all be considered to influence these terms in power calculations.

[0093] Figure 2 A block diagram of a wireless communication system in which a base station 100 communicates with a UE 200 according to an embodiment disclosed herein is shown. In one embodiment, the base station 100 includes a transceiver 110, a RACH configuration controller 120 including an association engine 120a, a communicator 130, a processor 140, and a memory 150. The base station 100 may be, for example, but not limited to, a next-generation NodeB (gNB), an evolved NodeB (eNB), NR, etc. The transceiver 110 may be configured to communicate with the UE 200 via the wireless communication system.

[0094] In one embodiment, the RACH configuration controller 120 configures RMSI information for the RACH configuration. The RACH configuration includes the association between the RACH resource and at least one of the SS block and CSI-RS resource. The association engine 120a is configured to associate the RACH resource with the SS block and the CSI-RS resource.

[0095] RACH Resource Association: An SS block consists of a PSS, SSS, and PBCH. Typically, one SS block is transmitted on one beam. Therefore, one SS block is associated with one beam on the TRP DL beam. Association between SS blocks and RACH resources and / or RACH preamble indices can be supported for NR and future radio systems via broadcast signaling / instructions to UE 200 or dedicated signaling. Furthermore, for NR above 6 GHz, the number of SS blocks that can be supported is 64. A total of 64 beams are supported to cover a 120-degree azimuth and 30-degree elevation scan range. This design is known to be possible using composite beams from multiple transceiver units (TXRUs) within the transmit-receive point (TRP), which may lead to beam pattern distortion. This indicates that the optimal SS block index can only form associations between the wide SS block associated beam and the RACH resource / index.

[0096] Furthermore, this association is useless for achieving high data rates and fine-grained beam management in connected mode. Typically, for a UE 200 in connected mode, this association may have to follow a P1 / P2 process to determine the optimal beam for data transmission purposes. To avoid such a delayed process, at least in handover situations, it is beneficial to rely on cell-specific / non-UE-specific reference signals (RS) to form an association with RACH resources / preamble indices. If cell-specific / non-UE-specific RS is used as the RS, multiple TXRUs in the TRP can have independent resources in the frequency domain / code domain / sequence domain for transmitting cell-specific / non-UE-specific RS. In this case, the UE 200 can receive cell-specific / non-UE-specific RS without any distortion in beam mode and can establish a high data throughput link with the target base station (e.g., gNB) immediately after the RACH process.

[0097] Since the RACH procedure used for handover is typically contention-free, the UE 200 can be instructed to associate the CSI-RS resources used for Layer 3 (L3) mobility with the RACH resources in the target base station. This procedure enables high-volume data transmission immediately after the RACH procedure is completed. However, it is clear that only one association mechanism is defined for RACH procedures based on SS blocks or CSI-RS, and this can be indicated to the UE 200. For example, if no additional RRC signaling is indicated to the UE 200, an SS block-based association can be assumed by default; otherwise, additional RRC signaling can indicate a CSI-RS-based association.

[0098] Consider that 1 SS block = 1 SS beam associated with 1 RACH resource. Furthermore, if several CSI-RS beams are within a single SS block, associating them all with 1 RACH resource could lead to conflicts. Then, each of those CSI resources can be associated with 1 RACH resource. To avoid excessive associations, the following can be done:

[0099] Each of the RACH resources surrounding the SS-based RACH resource can be used for CSI-based mapping. Then, in the time domain, different SS-based RACH resources can be used; furthermore, the number of Msg1 transmissions can be configured for the UE 200 based on the UE 200's beam mapping capability (which can be exchanged between the source and target base stations).

[0100] In general, association based on SS blocks and CSI-RS is feasible. Either SS block or CSI-RS resources can be configured as needed, and only one can be used at a time. If frequency division multiplexing (FDM) of both CSI-RS and SS blocks is supported, both can be supported simultaneously. If TDM of CSI-RS and SSS is used, there may be some latency when accessing one resource compared to the other. There are some trade-offs between performing narrow-beam-based RACH and time delay. SS blocks and CSI-RS can be configured accordingly. There are three possible options, as follows:

[0101] Option 1: Use only CSI-RS-based association, and not SS-block-based association. For example, UE 200 obtains CSI-RS configuration information from the SIB simultaneously with RACH resource configuration;

[0102] Option 2: Configurability between SS-block-based and CSI-RS-based associations. If the CSI-RS configuration information is included in the SIB, UE 200 assumes a CSI-RS-based RACH resource configuration; otherwise, it is an SS-block-based association.

[0103] Option 3: RACH resource configuration based on SS blocks. Typically, RACH resources based on CSI-RS can be configured for a contention-free process. This CSI-RS can be UE-specific.

[0104] This information is carried in the PBCH or RMSI. This information can be beam-common or beam-specific. Here, beam refers to the SS block or CSI-RS. Beam-common means that all beams carry all information about all possible associations. However, this results in a large amount of data consumption. To avoid this, each beam can carry its own scheduling information, which is mapped from the SS block or CSI-RS to the RACH resource by time and frequency.

[0105] However, if designed in a cell-specific manner, beam commonality cannot be avoided. Therefore, the following RACH configuration is defined:

[0106] Option 1: The RACH configurations of the SS blocks are the same. The following describes the RACH resource association rules used to determine the corresponding RACH resources;

[0107] Option 2: Some configuration parts of the SS blocks are the same, and the time / frequency positions may differ between different SS blocks; and

[0108] Option 3: Different RACH configurations for SS blocks.

[0109] The RACH configuration controller 120 of base station 100 configures the RACH configuration, wherein the RACH configuration is a common RACH configuration for all SS blocks, a partially common RACH configuration for all SS blocks, and one of the different RACH configurations for all SS blocks (e.g., Figures 4 to 6 (As shown). For example, RACH configuration controller 120 sends a common RACH configuration for all SS blocks. In one example, certain parts of the RACH configuration are common across all SS blocks. In another example, a different RACH configuration is used for all SS blocks.

[0110] RACH Resource Association Rules for Initial RACH Access: In one embodiment, RACH resource association rules need to be appropriately defined and indicated to the user. In one embodiment, the RACH configuration controller 120 is configured to broadcast RACH configuration in the SS block used for RMSI within the cell. The SS block is the beam used by the base station 100 during initial RACH access. The SS block includes the PSS, SSS, and Physical Broadcast Channel (PBCH). The PBCH includes MIB messages from which SIB messages can be extracted. Furthermore, the SIB messages include the RACH configuration.

[0111] Base station 100 can configure the association between SS blocks / CSI-RS and subsets of RACH resources based on the following:

[0112] A subset of RACH resources and an SS block / CSI-RS timing; and

[0113] A subset of RACH resources and multiple BCH / SS / CSI-RS opportunities.

[0114] In one embodiment, the association engine 120a is configured to indicate that the associations of the PBCH include MIB messages, and one of the RMSIs includes SIB messages, and other system information (OSI) includes SIB messages.

[0115] In one embodiment, the association engine 120a is configured to indicate associations both explicitly and implicitly. In an explicit manner, the association engine 120a is configured to carry all MIB / SIB messages, carrying the same information about the association. In an explicit manner, the association engine 120a is configured to carry each MIB message or SIB message, carrying different information about the association (e.g., ...). Figures 4 to 6 (As shown).

[0116] In an implicit manner, the association engine 120a is configured to indicate associations based on various parameters (such as system frame number (SFN), number of RACH resources, etc.) via equations, as shown in equation (2):

[0117] Idx RACH =((Idx) SSblock –(SFN*M*N RACH +m*N RACH )%N SSblocks )%N SSblocks )

[0118] ----(2)

[0119] Where, N SSblocks : (SS blocks transmitted in each cycle of a time slot) * 7;

[0120] M: Number of RACH bursts;

[0121] N RACH The number of RACH opportunities within a RACH burst;

[0122] m: 0,…M-1;

[0123] Idx RACH UE 200 transmits the Orthogonal Frequency Division Multiplexing (OFDM) symbol index for RACH; and Idx. SSblock : Estimated SS block index.

[0124] In one embodiment, association engine 120a is configured to associate RACH resources with one of SS blocks and CSI-RS resources based on at least one of time-based mapping and frequency-based mapping. In the example, time-based mapping is based on a time-based mapping of RACH resources, and frequency-based mapping is based on a frequency-based mapping of RACH resources, such as... Figure 7 or Figure 8 As shown.

[0125] In one embodiment, base station 100 uses at least one of RMSI, PDCCH, and PBCH to indicate multiple bits for RACH configuration in RMSI to UE 200. Furthermore, the RACH configuration in RMSI is indicated from the MSB of multiple bits or from the LSB of multiple bits (e.g., ...). Figures 9 to 11 (As shown). In the example, consider that the multiple bits used for RACH configuration are variable. Then, the base station 100 indicates to the UE that multiple bits in the RMSI and the "x" bit in the total multiple bits are used for RACH configuration. Therefore, the base station 100 indicates to the UE 200 that the "x" bit is located in the MSB or LSB of the total multiple bits.

[0126] In one embodiment, base station 100 uses RMSI PDCCH to indicate to UE 200 the positions of multiple bits in RMSI PDSCH used for RACH configuration. In one embodiment, the multiple bits are fixed for RACH configuration.

[0127] RACH resource association rules for contention-free / switchable RACH: In one embodiment, association engine 120a configures the association between RACH resources and at least one of a plurality of SS blocks and a plurality of CSI-RS resources.

[0128] In one embodiment, the association engine 120a associates at least one of the following: the RACH resource used for switching RACH with a resource within the same set of PRACH resources used for initial access RACH resources, the PRACH resource completely separated from the initial access RACH resource, and the resource partially overlapping with the initial access RACH resource.

[0129] In one embodiment, the relationship between CSI-RS resources and SS blocks is based on the quasi-co-location (QCL) relationship between CSI-RS resources and SS block resources. Furthermore, association engine 120a associates RACH resources with at least one of multiple SS blocks and multiple CSI-RS resources based on the QCL relationship between CSI-RS resources and SS block resources (as shown in Figures 13a to 14b).

[0130] In the example, when CSI-RS and SS blocks are associated based on QCL, all configuration parameters of CSI-RS are the same as those of SS blocks and / or some configuration parameters of CSI-RS are the same as those of SS blocks.

[0131] In one embodiment, communicator 130 is configured to communicate with UE 200 and internally communicate between hardware components in base station 100. In one embodiment, processor 140 is configured to process various instructions stored in memory 150 for managing RACH configuration in a wireless communication system.

[0132] Memory 150 may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM). Additionally, in some examples, memory 150 may be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or propagating signal. However, the term "non-transitory" may not be interpreted as memory 150 being immovable. In some examples, memory 150 may be configured to store more information than is typically stored. In certain examples, a non-transitory storage medium may store data that can change over time (e.g., in random access memory (RAM) or a cache).

[0133] In one embodiment, UE 200 includes transceiver 210, RACH configuration controller 220 including association engine 220a, communicator 230, processor 240, and memory 250. Transceiver 210 can be configured to communicate with base station 100 via a wireless communication system.

[0134] UE 200 may include, for example, cellular phones, smartphones, personal computers (PCs), minicomputers, desktop computers, laptop computers, handheld computers, PDAs, etc. UE 200 can support various radio access technologies (RATs), such as Code Division Multiple Access (CDMA), General Packet Radio Service (GPRS), Evolved Data Optimized EVDO (EvDO), Time Division Multiple Access (TDMA), Global System for Mobile Communications (GSM), Global Microwave Access Interoperability (WiMAX) technology, LTE, LTE Advanced, and 5G communication technologies.

[0135] In one embodiment, the RACH configuration controller 220 is configured to receive RMSI information including RACH configuration from the base station 100. The RACH configuration includes an association between RACH resources and one of the SS blocks and CSI-RS resources. The association engine 220a is configured to associate RACH resources with the SS blocks and CSI-RS resources.

[0136] In one embodiment, the RACH configuration controller 220 is configured to receive RACH configuration in an SS block used for RMSI within the cell.

[0137] In one embodiment, the RACH configuration controller 220 is configured to decode multiple bits of RACH configuration from the RMSI of the base station 100 using at least one of the RMSI, PDCCH RMSI, and Physical Broadcast Channel (PBCH).

[0138] In one embodiment, the RACH configuration controller 220 is configured to decode the RACH configuration in the RMSI starting from the MSB of multiple bits or from the least significant bit (LSB) of multiple bits. For example, considering a scenario where the multiple bits of the RACH configuration are variable, the UE 200 decodes the "x" bit of the RACH configuration from the MSB of multiple bits or from the LSB of multiple bits.

[0139] In one embodiment, the RACH configuration controller 220 is configured to use RMSI PDCCH to decode the positions of multiple bits of RACH configuration in the RMSI PDSCH from the base station 100.

[0140] In one embodiment, the RACH configuration controller 220 is configured to perform a random access procedure based on association.

[0141] In one embodiment, the RACH configuration controller 220 is configured to receive from the base station 100 an association between RACH resources and at least one of a plurality of SS blocks and a plurality of CSI-RS resources. Furthermore, the RACH configuration controller 220 is configured to perform a random access procedure for RACH handover based on the association.

[0142] In one embodiment, the RACH configuration controller 220 is configured to receive a set of parameters for at least one of RACH message 1, RACH message 2, RACH message 3, and RACH message 4 in the RACH configuration of the RMSI.

[0143] In one embodiment, communicator 230 is configured to communicate with UE 200 and internally communicate between hardware components in base station 100. In one embodiment, processor 240 is configured to process various instructions stored in memory 250 for managing RACH configuration in a wireless communication system.

[0144] Memory 250 may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM). Additionally, in some examples, memory 250 may be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or propagating signal. However, the term "non-transitory" may not be interpreted as memory 250 being immovable. In some examples, memory 250 may be configured to store more information than is typically stored. In certain examples, a non-transitory storage medium may store data that can change over time (e.g., in random access memory (RAM) or a cache).

[0145] Although Figure 2 Various hardware components of base station 100 and UE 200 are shown, but it should be understood that other embodiments are not limited thereto. In other embodiments, base station 100 and UE 200 may include fewer or more components. Furthermore, the labels or names of components are for illustrative purposes only and do not limit the scope of this disclosure. One or more components may be combined to perform the same or substantially similar functions for managing RACH configuration in a wireless communication system.

[0146] Figure 3 A flowchart 300 illustrates various operations for performing a random access procedure based on the association between RACH resources and SS blocks and CSI-RS resources, according to embodiments disclosed herein.

[0147] Initial RACH Access: At 302, the method includes configuring RMSI information by base station 100, the RMSI information including RACH configuration, wherein the RACH configuration includes an association between RACH resources and one of SS blocks and CSI-RS. In one embodiment, the method allows RACH configuration controller 120 to configure RMSI information including RACH configuration, wherein the RACH configuration includes an association between RACH resources and one of SS blocks and CSI-RS resources.

[0148] At 304, the method includes indicating the RMSI from the base station 100 to the UE 200. In one embodiment, the method allows the RACH configuration controller 120 to indicate the RMSI to the UE 200.

[0149] At 306, the method includes base station 100 indicating to UE 200 multiple bits of RACH configuration in RMSI using at least one of RMSI, PDCCH RMSI, and PBCH. In one embodiment, the method allows RACH configuration controller 120 to indicate to UE 200 multiple bits of RACH configuration in RMSI using at least one of RMSI, PDCCH RMSI, and PBCH.

[0150] In one embodiment, the RACH configuration controller 120 indicates the RACH configuration in the RMSI from a plurality of MSB bits or from a plurality of LSB bits.

[0151] In one embodiment, if the RMSI PDSCH consists of a field corresponding to other field information, then the MSB to X bits (where X is the length indicating the associated RACH configuration) can be used for decoding the RACH configuration, and further data from X+1 can be used for decoding other fields carried in the RMSI.

[0152] Furthermore, the RACH configuration controller 120 is configured to indicate to the UE 200 the positions of multiple bits of the RACH configuration in the RMSI PDCCH. Moreover, these multiple bits are fixed for the RACH configuration.

[0153] Consider a scenario where L' represents the length of the data vector indicating the mapping, where L' <= L, and L is the actual number of SS blocks transmitted. If such an indication is provided via PBCH, the mapping of the RACH configuration can also be defined only for the case of L'SS blocks. Furthermore, not only the actual number of SS blocks, but also the SS block index is needed for this purpose. The "X" bits of the RACH configuration are fixed in the specification. Additionally, base station 100 indicates the RMSIPDSCH location (i.e., the location within the RMSI PDSCH) via the association between the RMSI PDCCH and the RACH configuration. Furthermore, UE 200 decodes the RMSI PDSCH and uses a fixed number of "X" bits for the RACH configuration.

[0154] Furthermore, even when L' is indicated in the RMSI or even the PBCH, the PRACH configuration can have a variable size because L' depends on the network implementation. This can be supported by a RACH configuration with a variable bit mapping size. If no SS blocks are actually being transmitted, a RACH configuration based on a fixed bit size mapping can be considered.

[0155] At 308, the method includes UE 200 receiving RMSI information including RACH configuration from base station 100. In one embodiment, the method allows RACH configuration controller 220 to receive RMSI information including RACH configuration from base station 100.

[0156] In 310, the method includes the UE 200 decoding multiple bits of RACH configuration from the RMSI of the base station 100 using at least one of the RMSI, PDCCH RMSI, and PBCH. In one embodiment, the method allows the RACH configuration controller 220 to decode multiple bits of RACH configuration from the RMSI of the base station 100 using at least one of the RMSI, PDCCH RMSI, and PBCH.

[0157] In one embodiment, the RACH configuration controller 220 is configured to decode the RMSI PDSCH, and then, if the RACH configuration indicates the MSB, the first “X” bits can be considered, or if the RACH configuration indicates the LSB, the last “X” bits can be considered.

[0158] In addition, the RACH configuration controller 220 is configured to use the RMSI PDCCH to decode the positions of multiple bits of the RACH configuration in the RMSI from the base station 100.

[0159] In 312, the method includes performing a random access procedure by the UE 200 based on an association. In one embodiment, the method allows the RACH configuration controller 220 to perform a random access procedure based on an association.

[0160] The various operations, actions, blocks, steps, etc. in flowchart 300 can be executed in the order they are presented, in different orders, or simultaneously. Furthermore, in some embodiments, without departing from the scope of this disclosure, some operations, actions, blocks, steps, etc., can be omitted, added, modified, skipped, etc.

[0161] Figure 4 This document illustrates an example scenario where all MIB / SIB messages, according to embodiments disclosed herein, send the same information about the association.

[0162] In one embodiment, base station 100 includes an association engine 120a configured to perform association between RACH resources and one of SS blocks and CSI-RS resources. In another embodiment, association engine 120a is configured to perform association between RACH resources and at least one of a plurality of SS blocks and a plurality of CSI-RS resources.

[0163] In one embodiment, base station 100 includes an association engine 120a configured to indicate an association between a RACH resource and one of an SS block and a CSI-RS resource. In another embodiment, base station 100 includes an association engine 120a configured to indicate an association between a RACH resource and at least one of a plurality of SS blocks and a plurality of CSI-RS resources. Base station 100 includes three ways to indicate associations to UE 200. In one example of explicit indication: all MIB / SIB messages carry the same information about the association; and

[0164] Each MIB / SIB message carries different information about the association.

[0165] In one example of implicit indication, a predefined equation is used.

[0166] PBCH includes MIB messages, RMSI includes SIB messages, and OSI includes SIB messages. For example... Figure 4 As shown, all MIB and SIB messages carry the same information about the association.

[0167] In addition, the parameters required for RACH configuration are as follows:

[0168] System Frame Number (SFN);

[0169] Number of RACH subframes within a system frame (NS);

[0170] The subframe number (ns) within the system frame number;

[0171] If the number of Rx beams that can be supported in the system frame is less than the total number of Rx beams, then the gNB receives the number of subframes of the MSG1 period by scanning the Rx beams.

[0172] Based on the preamble format (NOS, a 7-bit or 14-bit bitmap indicating the symbols that can be transmitted for PRACH, defining a RACH mapping mode similar to the SS block mapping mode), the symbol indices corresponding to the SS block and intra-frame mappings; and

[0173] The number of sub-bands, and the UE 200 can randomly select a sub-band from these sub-bands for Msg1 transmission, or the UE 200 can be explicitly instructed by the gNB which sub-band to use.

[0174] In one embodiment, the frequency location (start / center / end) of a RACH resource can be represented as an offset relative to an SS block, an RMSI location, or a wideband carrier center, which can be indicated in the PBCH / RMSI. The resource blocks (RBs) allocated to each RACH resource for the SS block and the number of RBs can be indicated in the RACH configuration transmitted via the RMSI. In the case of implicit mapping, a simple rule can be defined such that a number of SS blocks of “X” are mapped to each RACH resource. The number “X” can be transmitted to UE 200 via the RACH configuration.

[0175] Figure 5 Example scenarios are shown where each MIB / SIB message carries different information about the association, according to embodiments disclosed herein. In one embodiment, the MIB / SIB message carries the association between an SS block and a RACH resource. Figure 5 As shown, each SS block (i.e., SS block 1, SS block 2, SS block 3 and SS block 4) has different RACH resources, as indicated by different shades.

[0176] Table 1. Advantages of explicitly indicating RACH resources:

[0177]

[0178]

[0179] Figure 6 An example scenario is shown where a RACH burst is sent in one or more consecutive RACH moments according to embodiments disclosed herein.

[0180] like Figure 6 As shown, each RACH burst is transmitted in one or more consecutive RACH timings. Furthermore, a predetermined equation for indicating the RACH configuration is defined below equation (3):

[0181] [SFN, Subframe index, OFDM symbol index] = f (parameters) --- (3)

[0182] In one embodiment, the parameters of the RACH configuration include the SFN, the SS block number, the RACH timing number, and the RACH burst number in a RACH burst set. A RACH burst includes one or more consecutive RACH timings. Furthermore, the RACH burst set covers the full-beam scan corresponding to the SS burst set or CSI-RS used for L3 mobility configuration.

[0183] Implicit indication: In one embodiment, the RACH configuration controller 120 is configured to indicate to the UE 200 the association between RACH resources and SS blocks and CSI-RS resources using a predefined equation (2).

[0184] Figure 7 An example scenario is shown where RACH resources are numbered according to a frequency-based mapping, based on embodiments disclosed herein.

[0185] like Figure 7 The diagram illustrates a many-to-one mapping in the case of mapping between SS blocks and RACH resources. In this case, higher-order polynomials can be supported, and equation-based mapping may be inflexible and infeasible. Furthermore, the number of parameters to indicate the higher-order polynomials can vary depending on the network operator. This process requires providing a flexible number of bits in the RACH configuration, which may or may not be desirable. Moreover, these calculations can be complex on the UE side. Therefore, considering these facts, a bit-based association between SS blocks and RACH resources is desirable. The bit mapping provides the association between SS blocks and RACH resources. Based on this association, the actual number of bits used to transmit the SS block is indicated by the bit mapping.

[0186] Figure 8 An example scenario illustrating a random association between SS blocks and RACH resources according to embodiments disclosed herein is shown.

[0187] like Figure 8 The example mapping between SS blocks and RACH resources is shown. Multiple SS blocks are shown to be associated with the same RACH resource. The length of the above data field can be "L", where "L" is the total number of SS blocks sent by base station 100. The PRACH resource number and the mapping between SS blocks and PRACH resources are shown in... Figure 9 As shown in the diagram, mapping can be performed according to the following processes: time-based mapping and frequency-based mapping.

[0188] In one embodiment, frequency numbering is preferred because the amount of SS RACH resources required in real time can depend on the network implementation, such as the number of SS blocks supported by the network. For example, in the case of supporting a network with a small number of SS blocks, a small number of RACH slots (or symbols) are required. Since the number of RACH subbands and the size of each subband are indicated by the RACH configuration, UE 200 can easily calculate the frequency size allocated for the RACH. Then, based on the mapping indicated between SS blocks and RACH resources, UE 200 can infer whether the RACH resources belong to the next time step or the current time step.

[0189] Furthermore, based on the mapping indicated between SS blocks and RACH resources, UE 200 can infer whether the RACH resource belongs to the next time step or the current time step. Additionally, consider “L” SS blocks. When the gNB decides to use two RACH resources for these L SS blocks, the gNB can use 1 bit to indicate which RACH resource is associated with the corresponding SS block via an “L” length vector (e.g., [0 1 0 0 1 1….]), where a 0 at the i-th position indicates that the i-th SS block may have to use the first RACH resource, while a 1 indicates that the second RACH resource can be used to send Msg1. Similarly, if the gNB uses four RACH resources, the L length vector might be [00 01 10 00 11 00 10….].

[0190] Furthermore, the size of the indication varies depending on the total number of resources allocated by the gNB for RACH purposes. Since the RACH configuration is indicated via the RMSI PDSCH, the size of the configuration can be explicitly indicated to the UE 200 via the RMSI PDCCH itself or the PBCH. This allows the UE 200 to decode the RACH configuration controlled by each gNB and also provides flexibility to the gNB.

[0191] Furthermore, when providing a fixed-size RACH configuration, it limits the flexibility of the gNB, considering that many-to-one mapping can be supported for NR-RACH. Therefore, the advantages and disadvantages of fixed-size RACH configuration versus variable-size RACH configuration are discussed below. Figures 9 to 11 As shown in the diagram. The bitmap size depends on the time and frequency resources allocated by the network. In the frequency domain, the size depends on the number of sub-bands; in the time domain, the size depends on the network implementation, which in turn depends on the size of the resources desired for RACH configuration. RACH configuration is indicated via RMSI. One possible approach is to allow the network to explicitly indicate the required bitmap size for RACH configuration via RMSI, which explicitly mentions the size of the bitmap used for RACH configuration. Alternatively, another approach is to fix the number in the specification. Furthermore, it is explicitly stated that the following methods can be considered:

[0192] Base station 100 indicates to UE 200 via PBCH, wherein multiple bits of RMSI PDSCH corresponding to RACH configuration are indicated;

[0193] RMSI PDCCH indicates the allocation of RMSI PDSCH and the bits allocated for RACH configuration; and

[0194] Fixing the carrier frequency in the specification based on the number of SS blocks may limit the implementation of gNB.

[0195] Figure 9An example scenario illustrating the association between an SS block and a RACH resource according to embodiments disclosed herein.

[0196] like Figure 9 As shown, the indicator bits represent the number of SS blocks associated with each RACH resource, as fixed in the RMSI / PBCH supported / specification. Some parts may be fixed in the specification, while others may be indicated by PBCH / RMSI. For example, option (A): the total number of indicator bits, 8 bits (1 0 0 1 0 1 01); and option (B): the number of bits indicating how many SS blocks are associated with each RACH resource (such as 2 bits), (2 1 1 1).

[0197] In one embodiment, the indicator bits signify that the first two SS blocks, the third SS block, the fourth SS block, and the fifth SS block are associated with the first RACH resource, the second RACH resource, the third RACH resource, and the fourth RACH resource, respectively. The number of indicator bits can be reduced, and indicator bits can support uneven association between SS blocks and RACH resources. Furthermore, option (A) is a continuously readable overall bit mapping. Then, a continuous mapping is defined for each RACH resource and SS block based on the multiple continuously readable bits.

[0198] Figure 10 An example scenario illustrating the association between an SS block and a RACH resource according to embodiments disclosed herein is shown.

[0199] In one embodiment, the indicator bits represent "X" SS block groups associated with N RACH resources. This provides the size of each group. Figure 10 As shown, option (A) (10110001) including 8 bits of indicator bits can be considered, and option (B) including group size can be considered: 2 bits. Therefore, UE 200 interprets A as C({10}{11}{00}{01}), where C({10}{11}{00}{01}) is padded with a “1” bit, for example (2 3 0 1)+(1)=(3 4 1 2), for a total of 10 SS blocks.

[0200] There are 10 SS blocks and 4(X) SS block groups. The first SS block group (3 SS blocks) is associated with the first RACH resource. The second SS block group (4 SS blocks) is associated with the second RACH resource. The third SS block group (1 SS block) is associated with the third RACH resource. The fourth SS block group (2 SS blocks) is associated with the first RACH resource. Therefore, based on the order, a total of 10 SS blocks are associated with RACH resources.

[0201] Furthermore, the wrap-around mechanism ensures that mapping can handle the fact that remaining SS blocks can also be mapped to RACH resources.

[0202] Figure 11 An example scenario illustrating the association between SS blocks and RACH resources according to embodiments disclosed herein is shown.

[0203] In one embodiment, an indicator bit indicates which SS block group is associated with the RACH resource. The indicator bit consists of the start point and length of the SS block. Additionally, supplementary signaling includes the size of each indicator bit (if necessary), the indicator bit number, etc.

[0204] Consider that A has two indicator bits: the first indicator bit (00 (start point), (10) length): associated with the first RACH resource from the first SS block to the third SS block; the second indicator bit (11 (start point), (11) length): associated with the second RACH resource from the fourth SS block to the seventh SS block.

[0205] In one embodiment, this scenario offers greater flexibility and allows for easy support of non-uniform and non-continuous mappings through this mechanism. The total number of bits can be explicitly indicated or fixed in the 3GPP specification via RMSI / PBCH.

[0206] Figure 12 Flowcharts illustrating various operations for performing a random access procedure for handover RACH based on the association between RACH resources and at least one of a plurality of SS blocks and a plurality of CSI-RS resources, according to embodiments disclosed herein.

[0207] Contention-free RACH: In 1202, the method includes configuring the association between RACH resources and at least one of a plurality of SS blocks and a plurality of CSI-RS resources by base station 100. In one embodiment, the method allows RACH configuration controller 120 to configure the association between RACH resources and at least one of the plurality of SS blocks and a plurality of CSI-RS resources.

[0208] In 1204, the method includes indicating the association of a handover RACH from base station 100 to UE 200. In one embodiment, the method allows RACH configuration controller 120 to indicate the association of a handover RACH to UE 200.

[0209] In 1206, the method includes the UE 200 receiving from the base station 100 an association between RACH resources and at least one of a plurality of SS blocks and CSI-RS resources. In one embodiment, the method allows the RACH configuration controller 220 to receive from the base station 100 an association between RACH resources and at least one of a plurality of SS blocks and CSI-RS resources.

[0210] Furthermore, in 1208, the method includes a random access procedure for handover RACH performed by UE 200 based on association. In one embodiment, the method allows RACH configuration controller 220 to perform a random access procedure for handover RACH based on association.

[0211] The various operations, actions, blocks, steps, etc. in flowchart 1200 can be executed in the order they are presented, in different orders, or simultaneously. Furthermore, in some embodiments, without departing from the scope of this disclosure, some operations, actions, blocks, steps, etc., can be omitted, added, modified, skipped, etc.

[0212] Figures 13a and 13b illustrate a schematic diagram of the association between CSI-RS resources and RACH resources based on the QCL relationship between CSI-RS resources and SS blocks according to embodiments disclosed herein.

[0213] As shown in Figures 13a and 13b, the UE 200 measures an explicit mapping between CSI-RS resources and PRACH resources to be used for the subsequent contention-free RACH. Such mapping may be necessary in the handover case because the UE 200 may not be aware of the complete mapping and QCL information for all SS blocks and CSI-RS blocks of the target cell. Furthermore, the entire RACH configuration may or may not be passed to the UE 200 to keep the handover command size and RACH configuration payload manageable.

[0214] Furthermore, for handover scenarios, UE 200 has already received RACH configuration via the source cell's RMSI. Additionally, a coarse time-frequency location (coarse grid indication) can be initially indicated, for example, based on the starting point of time and frequency. Furthermore, UE 200 can infer some mapping between CSI-RS and SS blocks (based on some resources measured by CSI-RS and SS) to identify the exact resources within a coarsely indicated grid. Alternatively, UE 200 can be configured to transmit RACH on the same SS block based on the mapping between CSI-RS and SS blocks. That is, if CSI-RS resources 1 and 2 correspond to SS block 1, then UE 200 can transmit RACH of CSI-RS resources 1 and 2 on the RACH resources associated with SS block 1 and defined in the RACH configuration, as shown in Figure 13a. Alternatively, UE 200 can be configured to explicitly indicate the time offset / frequency offset between SS-based RACH resources and CSI-RS-based RACH resources, as well as QCL information between SS blocks and CSI-RS blocks / beams, as shown in Figure 13b. Alternatively, UE 200 can be configured to explicitly indicate the RACH resources of CSI-RS resources / beams.

[0215] Contention-free RACH resource location: Since the resources for handover (HO) / contention-free RACH can be (a) resources within the same PRACH resource set used for the initial access RACH resources, (b) resources completely separate from the PRACH resources of the initial access RACH resources, or (c) resources partially overlapping with the initial access RACH resources.

[0216] LTE uses option (a). The same mechanism can be used. For option (b), access speed may be faster in handover situations. UE 200 has a high-priority handover. Some resources in the initial access RACH resources can also be used if needed. If UE 200 moves very quickly, some periodicity of these RACH resource configurations, such as SPS, can also be considered. It can be network-configurable. The initial access RACH resources can be a backup for the contention-free RACH performed by UE 200 for HO. This is better when the load is high. It better improves the data rate. Sometimes, the overhead of this process may be more. Once UE 200 performs connection establishment, base station 100 can immediately send a signal to stop periodic resource allocation. For option (c), it is a combination of options (a) and (b). And based on trade-offs, option (c) can be selected.

[0217] Contention-free RACH: SS block represents a normal wide beam; cell-specific CSI-RS represents a normal narrow beam; also known as set2; in addition, UE-specific CSI-RS represents a dedicated narrower beam, also known as set1.

[0218] Each of these RSs can be associated with some RACH resources for UE 200 to perform RACH configuration. These resources can be referred to as SS-based RACH resources, set1-based RACH resources, and set2-based RACH resources.

[0219] Based on the above description, the following conclusions can be drawn. For contention-free RACH, the following procedure can be used: UE 200 performs neighboring cell measurements based on SS or set2. Based on the report sent by UE 200, the following options are feasible.

[0220] In one example, UE 200 performs measurements on SS and performs RACH on SS-based resources (beam refinement of set2 or set1 during Msg2 is possible, but its feasibility is unknown).

[0221] In one example, UE 200 performs measurements on SS, and the HO command includes set2 resources for performing RACH (beam refinement of set1 during Msg2 is possible).

[0222] In one example, UE 200 performs measurements on set2 and, after receiving the HO command, performs RACH on the RACH resource based on set2 (beam refinement of set1 during Msg2 is possible).

[0223] In one example, UE 200 performs measurements on set2, and the HO command is included in the set1 resource where RACH is performed (no further beam refinement is performed).

[0224] For dedicated RACH resources, UE 200 can be associated with the following: a cell-specific CSI resource exists, within which UE 200 is assigned a preamble. Alternatively, resources based on UE-specific CSI resources can be assigned to UE 200. This allows all resources to be configured specifically for each UE 200.

[0225] In one embodiment, the cell-specific CSI-RS configuration can be a 1-bit indication in the system information. If present, UE 200 can use CSI association; otherwise, UE 200 can fall back to SS-based association.

[0226] For future wireless systems, diversity mechanisms for contention-free RACH can be explored. Since the UE's capabilities are known, UE 200 can use some Tx diversity mechanisms for PRACH. These mechanisms can be similar to the PUCCH Tx diversity mechanisms used in LTE: SORTD, SFBC, SCDD, time-domain precoder looping, frequency hopping, etc., thereby improving the performance of the RACH process. These can also be used for unlicensed frequency bands where UE 200 information already exists and some additional configuration is required. This also requires an advanced PRACH receiver.

[0227] Figure 14a illustrates a schematic diagram of the association between CSI-RS resources and RACH resources in sequential order based on the CSI-RS index of all CSI-RS resources according to embodiments disclosed herein. In one embodiment, the number of resources allocated to a CSI-RS RACH resource depends on the preamble format. If one-to-one mapping is allowed for CSI-RS, i.e., many-to-one mapping is not allowed for CSI-RS RACH, then equality-based mapping from the resource set can be allowed starting with frequency-priority mapping. UE 200 can access the resources of CSI-RS RACH.

[0228] Figure 14b illustrates a schematic diagram of the association between CSI-RS resources and RACH resources in sequence order of a CSI-RS index based on switched RACH according to an embodiment disclosed herein.

[0229] In one embodiment, the number of resources allocated to a CSI-RS RACH resource depends on the preamble format used for handover purposes. Furthermore, for handover scenarios, UE 200 may only report a few CSI-RS resources. RACH resources may be allocated only for these CSI-RS resources. For contention-free random access (NR), if there are no conflict issues, the contention-free random access process is greatly simplified, involving only two steps. In the first step, UE 200 sends the configured preamble on the PRACH, and in the second step, UE 200 receives the random access response. Contention-free random access can be used in various situations. In the example, in the handover scenario, the target gNB may configure a dedicated preamble and PRACH for UE 200, and UE 200 may perform contention-free random access.

[0230] Figure 15 A flowchart 1500 illustrates various operations for calculating PRACH power levels according to embodiments disclosed herein.

[0231] In 1502 and 1504, the method includes obtaining the configuration of one or more cell groups (such as cell group 1 and cell group 2). In one embodiment, the method allows the RACH configuration controller 220 to obtain the configuration of one or more cell groups (such as cell group 1 and cell group 2). The configuration of a cell group is one or more configurations, such as parameter sets, priorities, waveforms, beamforming architecture, beamwidth, preamble size, preamble format, and other parameters that may affect RACH.

[0232] To change the priority level or based on Quality of Service (QoS), the maximum value of PREAMBLE_TRANSMISSION_COUNTER can be changed; for example, higher priority levels have higher values, and lower priority levels have lower values. This priority level can also be used to influence the parameters of Msg3, where the number of repetitions of Msg3 can be variable—higher priority levels have a higher number, and lower priority levels have a lower number.

[0233] In 1506, the method includes calculating the power level of PRACH resources. In one embodiment, the method allows the RACH configuration controller 220 to calculate the power level of PRACH resources. If the UE 200 transmits SRS on a cell and PRACH on the Scell, the power level of PRACH on the Scell ​​can be calculated using a power calculation similar to the one described above, based on the SRS parameter set, the PRACH parameter set of the Scell, Pcmax, waveform, and beamforming parameters. Equation (4) below is used to calculate the power level used for both cell transmission and PRACH transmission.

[0234]

[0235] In one embodiment, a similar formula can be used to calculate the power level of PRACH, while also taking into account the effects of parameter sets, waveforms, beamforming, and other factors.

[0236] In one embodiment, as in LTE, if UE 200 is configured with multiple TAGs, UE 200 can transmit PRACH in a secondary serving cell in parallel with PUSCH / PUCCH in different serving cells belonging to different TAGs upon higher-layer request, adjusting the transmission power of the PUSCH / PUCCH so that the total transmission power of the UE does not exceed Pcmax in the overlapping portion. However, it may also consider parameter sets, beams, and waveforms to calculate these power limits.

[0237] In one embodiment, such as in LTE, if UE 200 is configured with multiple TAGs, UE 200 can transmit PRACH in the secondary serving cell in parallel with SRS transmissions on subframes belonging to different serving cells of different TAGs, upon higher-layer request. If the total transmission power exceeds Pcmax on any overlapping portion of the symbols, the SRS is dropped. This dropping may sometimes be unnecessary when UE 200 is required to use a different waveform (such as DFT-s-OFDM) because the required backoff for this waveform is close to 3dB compared to CP-OFDM. Therefore, the dropping rule can also take into account parameter sets, beams, and waveforms to calculate these limitations.

[0238] In one embodiment, such as in LTE, if a PRACH transmission by UE 200 on a Pcell starting in subframe i1 of the MCG overlaps temporally with another PRACH transmission by UE 200 starting in subframe i2 of the SCG, and if subframes i1 and i2 overlap temporally for more than one symbol, and if the total power of the two PRACH transmissions would exceed Pcmax(i1, i2), then UE 200 can be configured to transmit PRACH on the Pcell using preamble transmission power PPRACH, as is done in LTE. UE 200 can discard or adjust the power of the PRACH transmission in subframe i2 of the SCG such that the total power does not exceed Pcmax(i1, i2), where Pcmax(i1, i2) is the transmission power configured as a linear value for the dual connectivity of the subframe pair (i1, i2), as described in the LTE specification. If UE 200 discards the PRACH transmission, UE 200 sends a power boost pause indicator to the higher layers. If UE 200 adjusts the power of PRACH transmission, UE 200 can send a power boost pause indicator to the higher layers. The pause command can again be used to calculate these limits based on parameter sets, beams, and waveforms. In addition, the limit Pcmax(i1,i2) can depend on the following limit: Pcmax(i1,i2,parameter set 1,parameter set 2,waveform 1,waveform 2,bandwidth 1,bandwidth 2,number of beams).

[0239] A simple calculation of Pcmax(i1, i2, parameter set 1, parameter set 2, waveform 1, waveform 2, bandwidth 1, bandwidth 2, number of beams) can be Pcmax(i1, i2) calculated for some reference configuration, and then delta offset is added to this value according to each change encountered in the cell group, i.e., delta offset - parameter set; delta offset - waveform; delta offset - beamwidth, etc. It can be a linear combination or a weighted linear combination, or it can be a function of some of all these parameters. The same principle can be applied to the calculation of power level or priority level or overlap rules, etc.

[0240] In one embodiment, as in LTE, UE 200 may, upon higher-layer request, transmit PRACH in the secondary serving cell of CG1 on subframe i1 or subframe i1+1 and / or in the serving cell of CG2 on subframe i2+1 in a serving cell of CG2, in parallel with SRS transmission on subframe i1 of different serving cells belonging to different TAGs of CG1 and different serving cells belonging to different TAGs of CG1. If the total transmission power of the UEs of all CGs exceeds Pcmax in any overlapping portion of the symbols, SRS is dropped in CG1. As described above, the impact of power levels can be considered while following these rules.

[0241] Figure 16 and Figure 17 Flowcharts 1600 and 1700 illustrate various operations for controlling PRACH power levels based on waveforms and parameter sets, according to embodiments disclosed herein.

[0242] In conventional methods and systems, the random access procedure is stopped even before the UE reaches the maximum random access (RA) transmission counter, prior to the power boost reaching the maximum power value. Furthermore, when the RA procedure stops, the UE needs to change its power level or switch beams. This causes the RA procedure to fail. Unlike conventional methods and systems, the proposed method does not change the power level when the maximum power level is reached. The proposed method can be used to scale / offset from a reference power level based on waveform and parameter sets.

[0243] In one embodiment, at 1602 and 1702, UE 200 calculates the base power level of the waveform (e.g., Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM)) and the base power level of the reference parameter set. Furthermore, at 1604-1608 and 1704-1708, UE 200 performs scaling or shifting of the power level values ​​by Δ based on changes in the waveform and parameter set. offset The calculation of the basic power level and the scaling or shifting of the power level are as follows:

[0244] Power Rise: The RA process stops when UE 200 reaches the maximum RA transmission counter even before the power rise reaches the maximum power value. However, if the power value reaches its maximum value with the power rise before reaching the maximum number of RA attempt counters, UE 200 can continue to transmit at the same power level. This behavior is similar to the LTE system. Therefore, in NR, the following values ​​and counters can be maintained similarly to LTE - PREAMBLE_TRANSMISSION_COUNTER; preamble TransMax; PCMAX, as in LTE - and two counters can be maintained: (a) a power level / power rise counter; and (b) an RA attempt counter.

[0245] However, if needed, an additional backoff mechanism can be defined as follows: if UE 200 reaches maximum power before the total retransmission counter expires, UE 200 can backoff its power by a predetermined amount, thus allowing for a larger power boost. This can help reduce interference with the network. Backoff can be implemented by UE 200 or indicated by the network based on network load.

[0246] RACH Message 3 Power Control: RACH Message 3 is transmitted using UL-SCH, and the necessary parameters for this transmission are obtained from the RAR and higher layers. In LTE, the Tx power of msg3 is based on the Tx power of the previously transmitted preamble and the parameter "Δ" transmitted from the system information signal.preamble_Msg3 ".

[0247] RACH message 3 power control is similar to PUSCH power control. The following is given for subframe i as LTE:

[0248]

[0249] Where j = 2 is used for the PUSCH transmission of Msg3. in, This refers to the initial target power of the preamble. The initial target power of the preamble (initial preamble power) and Δ... preamble_Msg3 The offsets between the preamble and Msg3 are provided by higher layers. PLC is the path loss estimate; for PRACH, α c =1, Δ TF,c Dependent on PUSCH resource allocation. For RA, via ΔP rampup +δ msg2 Given f c (0), where δ msg2 TPC received from RAR, ΔP rampup The total power boost is based on the preamble obtained from the first to the last preamble of the serving cell transmitted from Msg1, which is requested by the higher layers.

[0250] ΔP rampup The power accumulation value of Msg3: Whether it remains the same as the UL Tx beam or varies between Msg1 and Msg3, UE 200 can use Δb as is. rampup This is because Δa rampup The total value represents the power level required for the UE's Msg1 to reach the gNB. Considering the power boosting behavior defined for Msgl (where the power boosting counter does not change during beam switching), similarly, Δn can be used. rampup Without changing, it is independent of the beam used between Msg1 and Msg3. After Msg4, a similar method with the initial PUSCH transmission power can be applied to calculate the initial PUCCH transmission power, and the same calculation can be used for the gc(i) parameter of the PUCCH.

[0251] Other options available for this parameter are (a) a value of 0, since no information is available; (b) a scaling or shift value based on the QCL information between the Msg1 and Msg3 beams; and (c) a conservative backoff value. If the shift value contains some information, it can be indicated by the gNB in ​​the RAR. This may be effective for cases where there is no beam correspondence. For cases where there is beam correspondence, the same beam can be used without problems. For cases where there is no beam correspondence, UE 200 uses some relevant beams because UE 200 has some knowledge about the relevant beams that UE 200 can try, for example, based on path loss calculations of the SS block. The shift and scaling may depend on the difference between the PL measurements between these beams, which are performed during the synchronization phase.

[0252] When UE 200 attempts different beams in Msg1, UE 200 can maintain a counter for each beam. Then, ΔP can be used based on the beams attempted by UE 200 and the increase in power used by UE 200 on each beam. rampup Therefore, UE 200 maintains ΔP for each beam. rampup Alternatively, a scaling value can be used to boost the total power.

[0253] PLc Path Loss Parameter: PLc indicates the path loss estimate used. Typically, this is calculated based on the beams for which the UE 200 has already completed SS block measurements. The appropriate available path loss value can be used depending on which Tx-Rx beam pair the UE 200 and gNB use for Msg3. Note here that gNB beam information may not be available in the UE. Therefore, it is referred to as "appropriately available PL measurement".

[0254] For example, this might mean that available path loss measurements can be obtained from DL synchronization measurements (because this measurement takes into account parameters, namely, the beam gain and width of the gNB DL beam for the SS block and the UE 200 beam for SS block reception). If the gNB expects any changes in the beam pattern, δ can be used. msg2 The variables are indicated in the RAR message. If the UE 200 anticipates any changes to the UE's Msg3 beam when compared to the beam used for PL measurements, these changes can be appropriately considered on the UE 200 side based on scaling factors according to the UE 200 beam parameters. The UE may use some UE 200-side offsets, such as scaling for beam gain / scaling for beamwidth. If the gNB changes, this can be indicated via the RAR.

[0255] To account for changes such as (a) the RAR being used for synchronous measurements, or (b) the RAR indicating changes in measurements, or (c) the RAR including some reference signal configurations that can be used for DL ​​measurements. These DL measurements can be used to update the PL calculation for Msg3 on the UE 200 side. Typically, the same concept can be used to indicate changes on the gNB side—using the RAR to indicate changes on the gNB side, or using the RAR to configure the UE 200 to measure new signals to identify gNB parameters.

[0256] Alternatively, the gNB can indicate its beam parameters via RMSI. The UE 200 can use these parameters to describe path loss measurements. This is useful information because beam gain and beamwidth affect this parameter. For connected mode, the gNB can explicitly indicate all these values ​​to the user. The gNB can configure the UE 200 with path loss values ​​that the gNB has already measured using, for example, SRS or PRACH. For connected mode, RACH is feasible; for initial access, PRACH can use some default values, or beam parameters can be disregarded. The UE 200 can report the PRACH transmission power in Msg3 (and the gNB can configure the path loss value in Msg4), which can be used for subsequent PUCCH and other transmissions.

[0257] Since this process is still in the initial access phase, the gNB may not be able to instruct the UE 200 to use a specific beam and path loss value suitable for the gNB-UETx Rx beam pair (note that this problem is more pronounced in the absence of a corresponding beam). If the UE 200 senses high interference in the environment, the only indication the gNB can provide to the UE 200 is to instruct the use of some alternative beam instead of the same beam used for Msg1. In such a case, if no measurements are available for the Msg3 beam, the UE 200 can use PLc=0 to avoid interference during Msg3 transmission. While using PLc=0 may be a conservative choice and could affect the gNB's Msg3 transmission and reception, it can be observed that using any other randomly chosen value and causing more interference to the network might be more impactful. PLc can be a scaled value based on the QCL information available to the UE 200, where interpolation can be made from available measurements. The same mechanism of scaling between frequencies, as in LTE FDD systems, can be implemented. In LTE FDD, DL and UL reside on different frequencies. Similarly, when DL and UL can be located on different beams in 5G, scaling / shifting, as is done in LTE FDD systems, can be used.

[0258] Another issue regarding path loss measurement might be how to calculate PLC. In LTE, PLC is calculated as “Reference Signal Power - RSRP of Higher Layer Filtering”. Here, the reference signal power refers to the power calculated using the downlink reference signal during the synchronization phase or periodic measurements when the synchronization signal is available. Since path loss values ​​can be measured once the beam is established, the provided method can follow the same mechanism as in LTE. This likely already covers the impact of beam measurements. Path loss measurements can already cover beam-specific (beam gain and width) calculations. Therefore, if the beam is maintained at each step of the RACH procedure, no further changes may be needed. However, if it changes for some reason, some indication is required. For example, in connected mode, the PDCCH uses a wide beam while the PDSCH uses a narrow beam. In such cases, new measurements can be performed or the gNB can indicate to the UE 200, allowing appropriate changes to be considered.

[0259] The impact of power spectral density differences between different parameter sets can be described in the P0, PUSCH values. In NR, the number of symbols per slot is 7 or 14. Depending on the number of slots, the Msg3 resource allocation can instruct the UE 200 to use some appropriate scaling offset based on the number of symbols. If the RAR content does not take this into account based on the PUSCH allocation, the UE 200 can interpret the allocation and add an offset to itself based on the slot length. This offset can be defined as Poffset, sym_length. It can have symbol length values ​​from 1 to 14 and can be predefined in the specification.

[0260] The defined new offset: Since the power level to be used can be changed based on the beamforming parameters used by the UE 200, and the power level is UE 200 specific, therefore the value... This can be a definition defined in the 3GPP specification. It depends on (a) beamwidth, (b) beam gain, and other parameters. Furthermore, any dependencies on gNB beam parameters can be indicated in the RAR, and... Only changes on the UE 200 side are considered. If it is found necessary to introduce parameter sets and waveform-specific power control in the NR, then It may also depend on the specific set of parameters and / or waveforms used for Msg3 transmission. This value can also be indicated by higher layers. For LTE, there is a difference between Msg11.25kHz and Msg315kHz. Existing parameters To compensate for these differences, in NR, the Msg3 parameter set can be dynamically changed based on PRACH and PUCCH multiplexing. The Msg3 parameter set can then be changed from 15kHz to 30kHz, 60kHz, 120kHz, or 240kHz, depending on the supported parameter sets. In this case, an offset parameter may be required, which can simply be a scaling factor predefined in the 3GPP specification.

[0261] Furthermore, based on the parameter set indication, the UE 200 can appropriately adjust the power level. For example, this might be based on channel effects. In some cases, a 15kHz parameter set works well due to Doppler conditions, while in others, 30kHz might be effective. To compensate for this and for gNB implementation reasons, a specific parameter set can be used. In this case, a higher power level can be used to compensate for channel effects.

[0262] Similar reasoning can be used for different waveforms. This is defined in the 3GPP specification a-priori. For example, in the cases of DFT-s-OFDM and pi / 2BPSK, some higher power levels can be used because higher power levels have lower PAPR. For CP-OFDM, some lower power levels can be used due to the high PAPR. Therefore, a reference value can be indicated to the UE 200 based on CP-OFDM. If other waveforms are used, the shift value can be indicated by this offset. In LTE, only DFT-s-OFDM is used for the uplink. However, in 5G, DFT-s-OFDM, CP-OFDM, and pi / 2BPSK waveforms can be used. Therefore, all of these can be considered. The waveform to be used can be implicitly or explicitly indicated. Therefore, the UE 200 can also select the scaling value based on this indication. Figure 2 and Figure 3 An example is shown below.

[0263] In one embodiment, the reference parameter set can be one of several possible waveforms that can be indicated in spec / DCI / MAC CE / RRC / SI. Furthermore, similar numbers can be extended for the parameter set case. The reference parameter set can be one of several possible parameter sets that can be indicated in spec / DCI / MAC CE / RRC / SI. The indication of the reference parameter set and waveform may also be useful for connected mode operation. The periodicity of the indication depends on the periodicity of the handover and can be achieved using DCI / MAC / RRC / SI. Where UE 200 must indicate these calculations to UE 200, some bits can be included in the power headroom report / uplink report. The number of bits depends on the number of supported parameter sets and the number of supported waveforms.

[0264] αc Scaling factor: similar to Parameter α c It can be configured to vary based on (a) beamwidth, (b) beam gain, and other parameters. It can also rely on these values ​​if it is found necessary to introduce a set of parameters and waveform-specific power control in the NR. The behavior of this parameter is related to... The same applies, and it is fixed in the 3GPP specification, or implicitly or explicitly indicated to the UE 200.

[0265] Consider the parameter sets for the RACH process. In one embodiment, the parameter sets for RACH messages 1, 2, 3, and 4 are described herein. The parameter set for RACH message 1 is the subcarrier spacing used to transmit the RA preamble. The parameter set can be selected based on the preamble detection performance under various settings. In this case, the parameter set for RACH message 1 can be indicated by the RACH configuration settings transmitted via RMSI. For example, the parameter set for RACH message 2 is indicated in PBCH / RMSI, the parameter set for RACH message 3 is indicated in PBCH / RMSI / RACH message 2, and the parameter set for RACH message 4 is indicated in PBCH / RMSI.

[0266] In one embodiment, RACH message 2 is a response to the transmission of RACH message 1 sent to UE 200. This involves decoding the NR-PDCCH in the Common Search Space (CSS) to decode the RAR content in the NR-PDSCH. Therefore, this involves the configuration of CORESET. The configuration of the UE-specific parameter set (or UE group-specific parameter set) can be associated with a specific service type of UE 200 or with the speed of the UE, as this is related to the Block Error Rate (BLER) implemented for a high (modulation coding scheme) MCS. These reasons do not apply to the CSS, and a single CSS configuration is sufficient. The parameter set used for NR-PDCCH transmission on the CSS can be a parameter set associated with initial access. In some embodiments, UE 200 needs to receive NR-PDCCH on CSS (e.g., for random access message scheduling) and NR-PDCCH on UE-DSS with different parameter sets. Priority rules may be applied (e.g., similar to BL / CE UE) to limit the complexity of UE 200 when UE 200 does not have multiple FFT filters (e.g., UE without CA capability), and it is generally expected that the scheduler can avoid such events.

[0267] In one embodiment, having a single CSS also enables all UEs 200 to perform a single random access procedure and avoids resource fragmentation (e.g., RA preamble), improves multiplexing capabilities (e.g., for UEs 200 that can be addressed by a single RAR message), and reduces the overhead associated with having multiple CSSs, multiple configurations that may be indicated in the MIB, and additional signaling in the SIB (indicating CSS configurations based on parameter sets). Therefore, a single CSS configuration that follows the same configuration as the PBCH is better for NR system operation by avoiding additional signaling to indicate the CORESET for RACH message 2 decoding purposes.

[0268] The RAR content indicates the resources that will be used for the transmission and retransmission of RACH message 3. This includes the Physical Resource Block (PRB) scheduling for UL-SCH resources. For a given bandwidth (BW), the PRB scheduling can vary depending on the set of parameters used for the transmission. For example, if X PRBs use a 15kHz subcarrier spacing (SCS), it is necessary to indicate that X / 2 PRBs use a 30kHz SCS. It is easy to see that this difference in SCS may force the use of a different DCI format to indicate the PUSCH allocation for RACH message 3. This may also increase: (a) the RAR payload if the parameter set must be included in the RAR; or (b) the blind decoding complexity on the UE 200 side if the parameter set is not indicated. Considering this, it seems unnecessary to use a separate parameter set for RACH message 3 transmission. In other words, the UE 200 can assume that RACH message 3 transmission is indicated in a default manner, in which case it can be the set of parameters used in PBCH transmission.

[0269] In one embodiment, RACH message 4 is a contention-resolving step that also transmits a Cell Radio Network Temporary Identifier (C-RNTI) that will be used by UE 200 for further communication. This involves NR-PDCCH and NR-PDSCH decoding. Even with RACH message 4 scheduled, the same reasoning given earlier for RACH message 2 still holds. There is no reason for RACH message 4 to use a different set of parameters compared to the previous RACH procedure steps. Therefore, it is preferred that RACH message 4 follows the same set of parameters as RACH message 2, which is the same set of parameters used for PBCH transmission.

[0270] Consider an explicit mechanism for parameter set indication. In another embodiment, UE 200 performs blind decoding on the parameter set of RAR / RACH message 2. UE 200 then obtains the parameter set indicated in the RAR for RACH message 3. Other RARs may follow a default parameter set; however, the RAR indicates the parameter set for RACH message 3. Furthermore, for RACH message 4, UE 200 may use the same parameter set as RAR / RACH message 2, or UE 200 may perform another blind decoding. These are the possibilities for RACH parameter set configuration. If RACH is deemed necessary for future wireless systems (beyond 5G communication systems), each step may also indicate the parameter set for other steps.

[0271] If the PBCH indicates the parameter set of the RMSI, then the UE's PRACH can be followed based on the RMSI parameter set. Therefore, the PRACH (RACH messages 2, 3, 4) can use the PBCH parameter set or the RMSI parameter set (as indicated by the PBCH or defined in the 3GPP specification) or as defined in the specification or indicated as above (through RAR and other steps).

[0272] The parameter set of Msg3 affects the power calculation used for Msg3. In LTE, the Tx power of msg3 is based on the Tx power of the previously transmitted preamble and the parameter "deltaPreambleMsg3" transmitted from the system information signal. For NR, since the parameter set of Msg3 may change, the parameter deltaPreambleMsg3 can take into account parameter set changes. Additionally, if the waveform of Msg3 is variable and not fixed, this parameter can be considered based on the backoff values ​​that may occur in the CP-OFDM and / or DFT-s-OFDM waveforms used for Msg3. Alternatively, the parameter can be set as "deltaPreambleMsg3Offset" in the 3GPP specification. This offset parameter can be used by the UE 200 itself based on the waveform / parameter set / beamforming mechanism being used by the UE 200. Therefore, the offset parameter can be defined as follows:

[0273] {

[0274] deltaPreambleMsg3Offset-numerology;

[0275] deltaPreambleMsg3Offset-waveform;

[0276] deltaPreambleMsg3Offset-beamfomring_mechanism;

[0277] deltaPreambleMsg3Offset-beamwidth;

[0278] }

[0279] or these functions

[0280] For LTE, the following table indicates the RAR content.

[0281] Table 2. RAR Content

[0282]

[0283] For NR, the RAR content may include the waveform of Msg3, the parameter set of Msg3, and the power offset of Msg3 based on the waveform and / or parameter set. PUSCH resource allocation may need to take into account the parameter set used. The resource block group (RBG) size can be scaled appropriately. By default, UE 200 can perform RBG calculations based on the parameter set indicated by MSg3 in the RAR content.

[0284] The bandwidth portion is typically configured only after the UE 200 enters connected mode. However, if the network decides to configure the bandwidth portion before it becomes part of the SI, such as for Narrowband Internet of Things (NB-IoT) / Enhanced Machine Type Communication (eMTC), the Msg3 narrowband index is indicated for transmission.

[0285] Table 3. Narrowband Index Msg3 PUSCH Information

[0286] Msg3 narrowband index value Msg3 PUSCH narrowband "00” <![CDATA[(NB RAR +1)towards N NB ]]> "01” <![CDATA[(NB RAR +2)towards N NB ]]> "10” <![CDATA[(NB RAR +3)towards N NB ]]> "11” <![CDATA[(NB RAR +4)towards N NB ]]>

[0287] NB RAR This is the narrowband used for the first subframe in the random access response. If only one narrowband is configured, it is determined by the higher layers; otherwise, it is determined as described in the 3GPP specification. For NR, the definition of the bandwidth portion is similar to that of the narrowband in eMTC. The above calculations can be used for NR, but using the concept of the BW portion. The number of bandwidth portions may change if the parameter set is linked to the BW portion. A function of the parameter set and the size of the bandwidth portion can be used to determine the Msg3 resource. For ease of allocation and indication, the wide bandwidth is divided into bandwidth portions as PRB groups.

[0288] Therefore, the gNB can use Msg2 to help the UE 200 obtain gNB-based beam parameter values. Other values ​​can be defined in the spec / implicit or explicit indication via RAR or system information (RMSI or PBCH or other system information). This is the behavior upon initial access. For connected mode, the gNB can use DCI signaling and / or RRC signaling to assist gNB-UE Tx RX beam-specific power management. The beam-specific parameters mentioned here can be indicated to the UE 200 via RACH configuration, allowing the gNB to indicate that the parameters can be changed and that Msg3 is taken into account for the UE 200.

[0289] In some embodiments, a method for operating a base station in a wireless communication system is provided. The method includes: generating Residual Minimal System Information (RMSI) including a Random Access Channel (RACH) configuration, wherein the RACH configuration includes an association between RACH resources and one of a Synchronization Signal (SS) block and a Channel State Information Reference Signal (CSI-RS) resource; and transmitting the RMSI to a User Equipment (UE). Preferably, the RACH configuration is broadcast in the SS blocks used for the RMSI within the cell. Preferably, the RACH configuration is a common RACH configuration for all SS blocks, a partially common RACH configuration for all SS blocks, and one of different RACHs for all SS blocks. Preferably, the RACH configuration in the RMSI indicates a set of parameters for at least one of RACH messages 1, 2, 3, and 4.

[0290] Preferably, the association between RACH resources and one of the SS blocks and CSI-RS resources is based on at least one of time-based mapping and frequency-based mapping. Preferably, at least one of the RMSI, Physical Downlink Control Channel (PDCCH) RMSI, and Physical Broadcast Channel (PBCH) is used to indicate to the UE multiple bits of the RACH configuration in the RMSI. Preferably, the RACH configuration in the RMSI is configured based on the most significant bit (MSB) or the least significant bit (LSB) of the multiple bits. Preferably, the RMSI PDCCH is used to indicate to the UE the position of multiple bits of the RACH configuration in the RMSI Physical Downlink Shared Channel (PDSCH). Preferably, the number of bits is fixed for the RACH configuration.

[0291] In some embodiments, a method for managing the configuration of a random access channel (RACH) in a wireless communication system is provided. The method includes: configuring an association between RACH resources and at least one of a plurality of SS blocks and a plurality of Channel State Information Reference Signals (CSI-RS) resources by a base station; and instructing a user equipment (UE) to switch the RACH association. Preferably, the association is indicated by one of a PBCH including a Master Information Block (MIB) message and an RMSI including a System Information Block (SIB) message, and one of other System Information (OSI) messages including a System Information Block (SIB) message. Preferably, all MIB messages or SIB messages send the same information about the association. Preferably, each MIB message or SIB message sends different information about the association. Preferably, the association is defined by the equation Idx. RACH =((Idx) SSblock –(SFN*M*N RACH +m*N RACH )%N SSblocks )%N SSblocks ) indicates; N SSblocks : (SS blocks transmitted in each cycle of a time slot) * 7; M: Number of RACH bursts; N RACH : The number of RACH opportunities within a RACH burst; m: 0,…M-1; Idx RACH : The Orthogonal Frequency Division Multiplexing (OFDM) symbol index transmitted by the UE for RACH; and Idx SSblock : Estimated SS block index.

[0292] Preferably, the RACH resource for switching RACH is at least one of the following: a resource within the same PRACH resource set used for the initial access RACH resource; a resource completely separate from the PRACH resource used for the initial access RACH resource; or a resource partially overlapping with the initial access RACH resource. Preferably, the relationship between CSI-RS resources and SS blocks is based on a quasi-co-address (QCL) relationship between CSI-RS resources and SS block resources. Preferably, the association between RACH resources and at least one of multiple SS blocks and multiple CSI-RS resources is based on a QCL relationship between CSI-RS resources and SS block resources.

[0293] In some embodiments, a method for operating a user equipment (UE) in a wireless communication system is provided. The method includes: receiving from a base station Residual Minimal System Information (RMSI) including a Random Access Channel (RACH) configuration, wherein the RACH configuration includes an association between RACH resources and one of SS blocks and Channel State Information Reference Signal (CSI-RS) resources; and performing a random access procedure based on the association. Preferably, the RACH configuration is broadcast in SS blocks used for the RMSI within the cell. Preferably, the RACH configuration is a common RACH configuration for all SS blocks, a partially common RACH configuration for all SS blocks, and one of different RACHs for all SS blocks. Preferably, the RACH configuration in the RMSI indicates a parameter set of at least one of RACH message 1, RACH message 2, RACH message 3, and RACH message 4. Preferably, the association between the RACH resources and one of the SS blocks and CSI-RS resources is based on at least one of a time-based mapping and a frequency-based mapping. Preferably, the method further includes: decoding multiple bits of the RACH configuration in the RMSI from the base station using at least one of the RMSI, the Physical Downlink Control Channel (PDCCH) RMSI, and the Physical Broadcast Channel (PBCH).

[0294] Preferably, the method further includes decoding the RACH configuration in the RMSI from a multiple-bit MSB or a multiple-bit LSB. Preferably, the UE uses the RMSI PDCCH to decode the positions of multiple bits of the RACH configuration in the RMSI PDSCH from the base station. Preferably, for the RACH configuration, the multiple bits are fixed.

[0295] In some embodiments, a method for managing the configuration of a random access channel (RACH) in a wireless communication system is provided. The method includes: a user equipment (UE) receiving from a base station an association between RACH resources and at least one of a plurality of SS blocks and a plurality of Channel State Information Reference Signals (CSI-RS) resources; and the UE performing a random access procedure for switching the RACH according to the association. Preferably, the association is indicated by one of a PBCH including MIB messages and an RMSI including System Information Block (SIB) messages, and one of other System Information (OSI) including SIB messages. Preferably, all MIB messages or SIB messages send the same information about the association. Preferably, each MIB message or SIB message sends different information about the association. Preferably, the association is defined by the equation Idx. RACH =((Idx) SSblock –(SFN*M*N RACH +m*N RACH )%N SSblocks )%N SSblocks ) indicates; NSSblocks : (SS blocks transmitted in each cycle of a time slot) * 7; M: Number of RACH bursts; N RACH : The number of RACH opportunities within a RACH burst; m: 0,…M-1; Idx RACH : The Orthogonal Frequency Division Multiplexing (OFDM) symbol index transmitted by the UE for RACH; and Idx SSblock : Estimated SS block index.

[0296] Preferably, the RACH resource for switching RACH is at least one of the following: a resource within the same PRACH resource set used for the initial access RACH resource; a resource completely separate from the PRACH resource used for the initial access RACH resource; or a resource partially overlapping with the initial access RACH resource. Preferably, the relationship between CSI-RS resources and SS blocks is based on a quasi-co-address (QCL) relationship between CSI-RS resources and SS block resources. Preferably, the association between RACH resources and at least one of multiple SS blocks and multiple CSI-RS resources is based on a QCL relationship between CSI-RS resources and SS block resources.

[0297] In some embodiments, a base station is provided for managing the random access channel (RACH) configuration in a wireless communication system. The base station includes: a memory; a processor; and a RACH configuration controller coupled to the memory and the processor, configured to: configure Residual Minimal System Information (RMSI) information including the RACH configuration, wherein the RACH configuration includes an association between RACH resources and one of SS blocks and Channel State Information Reference Signal (CSI-RS) resources; and indicate the RMSI to a User Equipment (UE). Preferably, the RACH configuration is broadcast in the SS blocks used for the RMSI within the cell. Preferably, the RACH configuration is a common RACH configuration for all SS blocks, a partially common RACH configuration for all SS blocks, and one of the different RACHs for all SS blocks. Preferably, the RACH configuration in the RMSI indicates a set of parameters for at least one of RACH message 1, RACH message 2, RACH message 3, and RACH message 4.

[0298] Preferably, the association between RACH resources and one of the SS blocks and CSI-RS resources is based on at least one of time-based mapping and frequency-based mapping. Preferably, the RACH configuration controller indicates to the UE multiple bits of the RACH configuration in the RMSI using at least one of the RMSI, the Physical Downlink Control Channel (PDCCH) RMSI, and the Physical Broadcast Channel (PBCH). Preferably, the RACH configuration controller indicates the RACH configuration in the RMSI from either the most significant bit (MSB) or the least significant bit (LSB) of the multiple bits. Preferably, the RACH configuration controller indicates to the UE the position of multiple bits of the RACH configuration in the RMSI Physical Downlink Shared Channel (PDSCH) using the RMSI PDCCH. Preferably, for RACH configuration, the multiple bits are fixed.

[0299] In some embodiments, a base station is provided for managing the configuration of a random access channel (RACH) in a wireless communication system. The base station includes: a memory; a processor; and a RACH configuration controller coupled to the memory and the processor, configured to: configure the association between RACH resources and at least one of a plurality of SS blocks and a plurality of Channel State Information Reference Signal (CSI-RS) resources; and indicate to a user equipment (UE) the association for switching RACH.

[0300] Preferably, the association is indicated by one of the PBCH (including MIB messages) and RMSI (including System Information Block (SIB) messages), and other System Information (OSI) messages including SIB messages. Preferably, all MIB messages or SIB messages send the same information about the association. Preferably, each MIB message or SIB message sends different information about the association. Preferably, the association is indicated by the equation Idx. RACH =((Idx) SSblock –(SFN*M*N RACH +m*N RACH )%N SSblocks )%N SSblocks ) indicates; N SSblocks : (SS blocks transmitted in each cycle of a time slot) * 7; M: Number of RACH bursts; N RACH : The number of RACH opportunities within a RACH burst; m: 0,…M-1; Idx RACH : The Orthogonal Frequency Division Multiplexing (OFDM) symbol index transmitted by the UE for RACH; and Idx SSblock : Estimated SS block index.

[0301] Preferably, the RACH resource for switching RACH is at least one of the following: a resource within the same PRACH resource set used for the initial access RACH resource; a resource completely separate from the PRACH resource used for the initial access RACH resource; or a resource partially overlapping with the initial access RACH resource. Preferably, the relationship between CSI-RS resources and SS blocks is based on a quasi-co-address (QCL) relationship between CSI-RS resources and SS block resources. Preferably, the association between RACH resources and at least one of multiple SS blocks and multiple CSI-RS resources is based on a QCL relationship between CSI-RS resources and SS block resources.

[0302] In some embodiments, a user equipment (UE) is provided in a wireless communication system. The equipment includes: a transceiver; and at least one processor coupled to the transceiver and configured to receive from a base station Residual Minimal System Information (RMSI) including a Random Access Channel (RACH) configuration, wherein the RACH configuration includes an association between RACH resources and one of an SS block and a Channel State Information Reference Signal (CSI-RS) resource; and to perform a random access procedure based on the association. Preferably, the RACH configuration is broadcast in an SS block used for RMSI within the cell.

[0303] Preferably, the RACH configuration is a common RACH configuration for all SS blocks, a partially common RACH configuration for all SS blocks, and one of the different RACH configurations for all SS blocks. Preferably, the RACH configuration in the RMSI indicates a parameter set of at least one of RACH message 1, RACH message 2, RACH message 3, and RACH message 4. Preferably, the association between the RACH resource and one of the SS blocks and CSI-RS resources is based on at least one of a time-based mapping and a frequency-based mapping.

[0304] Preferably, at least one processor is further configured to decode multiple bits of the RACH configuration in the RMSI from the base station using at least one of the RMSI, the Physical Downlink Control Channel (PDCCH), and the Physical Broadcast Channel (PBCH). Preferably, the UE decodes the RACH configuration in the RMSI from the MSB or the LSB of multiple bits. Preferably, the UE uses the RMSI PDCCH to decode the positions of the multiple bits of the RACH configuration in the RMSI PDSCH from the base station. Preferably, for the RACH configuration, the multiple bits are fixed.

[0305] In some embodiments, a UE is provided for managing the configuration of a random access channel (RACH) in a wireless communication system. The UE includes: a memory; a processor; and a RACH configuration controller coupled to the memory and the processor, configured to receive from a base station an association between RACH resources and at least one of a plurality of SS blocks and a plurality of Channel State Information Reference Signals (CSI-RS) resources; and to perform a random access procedure for handing over the RACH based on the association. Preferably, the association is performed via one of a PBCH including a MIB message, an RMSI including a System Information Block (SIB) message, and an OSI indication including a SIB message.

[0306] Preferably, all MIB messages or SIB messages send the same information about the association. Preferably, each MIB message or SIB message sends different information about the association. Preferably, the association is defined by the equation Idx. RACH =((Idx) SSblock –(SFN*M*N RACH +m*N RACH )%N SSblocks )%N SSblocks ) indicates; N SSblocks : (SS blocks transmitted in each cycle of a time slot) * 7; M: Number of RACH bursts; N RACH : The number of RACH opportunities within a RACH burst; m: 0,…M-1; Idx RACH : The Orthogonal Frequency Division Multiplexing (OFDM) symbol index transmitted by the UE for RACH; and Idx SSblock : Estimated SS block index.

[0307] Preferably, the RACH resource used for switching RACH is a resource within the same set of PRACH resources used for the initial access RACH resource, and is either completely separate from the PRACH resource of the initial access RACH resource or partially overlaps with the initial access RACH resource. Preferably, the relationship between CSI-RS resources and SS blocks is based on the quasi-colocation (QCL) relationship between CSI-RS resources and SS block resources. Preferably, the association between RACH resources and at least one of multiple SS blocks and multiple CSI-RS resources is based on the QCL relationship between CSI-RS resources and SS block resources.

[0308] The methods described in the claims and / or specifications of this disclosure can be implemented in hardware, software, or a combination of hardware and software.

[0309] When the method is implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within an electronic device. At least one program may include instructions that cause the electronic device to perform a method according to various embodiments of the present disclosure as defined by the appended claims and / or disclosed herein.

[0310] The program (software module or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), disk storage devices, optical disc (CD-ROM), digital versatile optical disc (DVD), or other types of optical storage devices or magnetic tape. Optionally, any combination of some or all of these can form the memory storing the program. Furthermore, many such memories can be included in an electronic device.

[0311] Additionally, the program can be stored on an attachable storage device accessible via a communication network, such as the Internet, intranet, local area network (LAN), wide area network (WAN), and storage area network (SAN), or a combination thereof. Such a storage device can be connected to electronic devices via an external port. Furthermore, a separate storage device on the communication network can be connected to portable electronic devices.

[0312] In the detailed embodiments described above, the components included in this disclosure are represented in a singular or plural form according to the presented detailed embodiments. However, for ease of description, the singular or plural form is chosen as appropriate for the presented situation, and the various embodiments of this disclosure are not limited to a single element or multiple elements. Furthermore, multiple elements expressed in the specification may be configured as a single element, or a single element in the specification may be configured as multiple elements.

[0313] Although this disclosure has been shown and described with reference to specific embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the embodiments, but should be defined by the appended claims and their equivalents.

[0314] Although this disclosure has been described with reference to various embodiments, various changes and modifications may be made to those skilled in the art. This disclosure is intended to cover such changes and modifications that fall within the scope of the appended claims.

Claims

1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: Receive information indicating the first subcarrier interval from the base station BS on the physical broadcast channel PBCH; The system information about the physical random access channel (PRACH) configuration is received from the BS using a first subcarrier interval, the system information including information indicating a second subcarrier interval; By using the second subcarrier interval to send a random access preamble to the BS; and By using the first subcarrier interval, a random access response (RAR) is received from the BS as a response to the random access preamble. The first subcarrier spacing and the second subcarrier spacing are different from each other and are configured from the BS.

2. The method according to claim 1, further comprising: Send message 3 to BS on the resource indicated by RAR; as well as The contention resolution message is received from the BS using the first subcarrier interval as a response to message 3.

3. The method according to claim 2, in, The system information includes information about the waveform of message 3, and Among them, the waveform of message 3 is either Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform Extended OFDM (FT-s-OFDM).

4. The method according to claim 2, in, The system information includes information indicating the subcarrier spacing of message 3.

5. A method performed by a base station (BS) in a wireless communication system, the method comprising: Send information indicating the first subcarrier interval to the user equipment (UE) on the physical broadcast channel PBCH; The system information regarding the physical random access channel (PRACH) configuration is transmitted to the UE using a first subcarrier interval, and the system information includes information indicating a second subcarrier interval. Receive random access preamble from UE by using a second subcarrier interval; and The random access response (RAR) is sent to the UE via the first subcarrier interval as a response to the random access preamble. The first subcarrier spacing and the second subcarrier spacing are different from each other and are configured from the BS.

6. The method according to claim 5, further comprising: Receive message 3 from UE on the resource indicated by RAR; as well as In response to message 3, a contention resolution message is sent to the UE using the first subcarrier interval.

7. The method according to claim 6, in, The system information includes information about the waveform of message 3, and Among them, the waveform of message 3 is either Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform Extended OFDM (FT-s-OFDM).

8. The method according to claim 6, in, The system information includes information indicating the subcarrier spacing of message 3.

9. A user equipment (UE) in a wireless communication system, the UE comprising: At least one transceiver; At least one processor, communicatively coupled to at least one transceiver; as well as At least one memory, communicatively coupled to at least one processor, stores instructions executable by the at least one processor alone or in any combination, such that the UE: Information indicating the first subcarrier interval is received from the base station BS on the physical broadcast channel PBCH. System information regarding the configuration of the Physical Random Access Channel (PRACH) is received from the BS using a first subcarrier interval. This system information includes information indicating a second subcarrier interval. By using the second subcarrier interval to send a random access preamble to the BS, and By using the first subcarrier interval, a random access response (RAR) is received from the BS as a response to the random access preamble. The first subcarrier spacing and the second subcarrier spacing are different from each other and are configured from the BS.

10. The UE according to claim 9, wherein, The instruction also causes the UE to: Send message 3 to the BS on the resource indicated by the RAR; and The contention resolution message is received from the BS using the first subcarrier interval as a response to message 3.

11. The UE according to claim 10, in, The system information includes information about the waveform of message 3, and Among them, the waveform of message 3 is either Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform Extended OFDM (FT-s-OFDM).

12. The UE according to claim 10, in, The system information includes information indicating the subcarrier spacing of message 3.

13. A base station (BS) for a wireless communication system, the BS comprising: At least one transceiver; At least one processor, communicatively coupled to at least one transceiver; as well as At least one memory, communicatively coupled to at least one processor, stores instructions executable by the at least one processor alone or in any combination, such that the BS: Send information indicating the first subcarrier interval to the user equipment (UE) on the physical broadcast channel PBCH; The system information regarding the physical random access channel (PRACH) configuration is transmitted to the UE using a first subcarrier interval, and the system information includes information indicating a second subcarrier interval. Receive random access preamble from UE by using a second subcarrier interval; and The random access response (RAR) is sent to the UE via the first subcarrier interval as a response to the random access preamble. The first subcarrier spacing and the second subcarrier spacing are different from each other and are configured from the BS.

14. The BS according to claim 13, wherein, The instruction also causes the BS to: Receive message 3 from UE on the resource indicated by RAR; as well as In response to message 3, a contention resolution message is sent to the UE using the first subcarrier interval.

15. The BS according to claim 14, in, The system information includes information about the waveform of message 3, and Among them, the waveform of message 3 is either Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform Extended OFDM (FT-s-OFDM).

16. The BS according to claim 14, in, The system information includes information indicating the subcarrier spacing of message 3.

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