Methods of wireless communication and scheduled entities between scheduled entities and scheduling entities
Patent Information
- Application Number
- CN202611011110.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2020-05-04
- Publication Date
- 2026-10-27
Smart Images
Figure CN122994809A_ABST
Abstract
Description
[0001] This patent application is a divisional application of the following invention patent application:
[0002] Application Number: 202080100361.7
[0003] Application date: May 4, 2020
[0004] Invention Title: Early Channel State Information Reporting in Random Access Channels Technical Field
[0005] The techniques discussed below generally relate to wireless communication networks, and more specifically, to techniques for providing channel state information in random access messages. Background Technology
[0006] In wireless communication systems (such as those specified under the 5G New Radio (NR) standard), an access point (e.g., a base station) can communicate with a user equipment (UE) (e.g., a smartphone). This communication can utilize a modulation and coding scheme (MCS), rank, and precoding matrix selected based on channel estimation between the base station and the UE. To assist the UE in estimating the channel, the base station can send one or more reference signals to the UE, such as a Channel State Information-Reference Signal (CSI-RS). After channel estimation, the UE can return a Channel State Information (CSI) report to the base station indicating channel quality. The CSI may include, for example, a Channel Quality Indicator (CQI) indicating the rank of the transmission to the UE, a Rank Indicator (RI) indicating the rank of the transmission to the UE, a Precoding Matrix Indicator (PMI) indicating the precoding matrix of the transmission to the UE, and other suitable parameters.
[0007] With the continued growth in demand for mobile broadband access and communications, research and development are constantly advancing wireless communication technologies to not only meet the growing demand for mobile broadband access but also to advance and enhance mobile communications. Therefore, this disclosure focuses on technologies and methods for improving the efficiency of devices and networks that rely on CSI / CQI reports, such as link adaptation. Summary of the Invention
[0008] The following provides an overview of one or more aspects of this disclosure in order to offer a basic understanding of these aspects. This overview is not a comprehensive summary of all anticipated features of this disclosure, nor is it intended to identify key or essential elements of all aspects of this disclosure, nor to depict the scope of any or all aspects of this disclosure. Its sole purpose is to present, in some form, some ideas of one or more aspects of this disclosure as a prelude to the more detailed description that follows.
[0009] In one example, a method for wireless communication between a scheduled entity and a scheduling entity in a wireless communication network is disclosed. The method includes, at the scheduled entity: receiving a downlink (DL) reference signal (RS) from the scheduling entity on a channel between the scheduling entity and the scheduled entity; obtaining channel state information (CSI) of the channel between the scheduling entity and the scheduled entity using the received DL RS; selecting an uplink resource associated with a random access procedure; multiplexing a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; and transmitting the multiplexed information to the scheduling entity in a random access message on the selected uplink resource.
[0010] In another example, a scheduled entity within a wireless communication network is disclosed, including a transceiver, a memory, and a processor communicatively coupled to the transceiver and the memory. The processor and memory are configured to receive a downlink (DL) reference signal (RS) from the scheduling entity on a channel between the scheduling entity and the scheduled entity, and to obtain channel state information (CSI) of the channel between the scheduling entity and the scheduled entity using the received DL RS. The processor and memory are also configured to select an uplink resource associated with a random access procedure, multiplex a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information, and send the multiplexed information to the scheduling entity in a random access message on the selected uplink resource.
[0011] In another example, a scheduled entity in a wireless communication network is disclosed, including a means module for receiving downlink (DL) reference signals (RS) from a scheduling entity on a channel between the scheduling entity and the scheduled entity, and a means module for obtaining channel state information (CSI) of the channel between the scheduling entity and the scheduled entity using the received DL RS. The scheduled entity may further include: a means module for selecting uplink resources associated with a random access procedure; a means module for multiplexing a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; and a means module for sending the multiplexed information to the scheduling entity in a random access message on the selected uplink resource.
[0012] In another example, a computer-readable medium storing instructions executable by one or more processors of a scheduled entity is disclosed to: receive a downlink (DL) reference signal (RS) from a scheduling entity on a channel between the scheduling entity and the scheduled entity; obtain channel state information (CSI) of the channel between the scheduling entity and the scheduled entity using the received DL RS; select an uplink resource associated with a random access procedure; multiplex a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; and send the multiplexed information to the scheduling entity in a random access message on the selected uplink resource.
[0013] In another example, a method for wireless communication between a scheduled entity and a scheduling entity in a wireless communication network is disclosed. The method includes, at the scheduled entity: receiving a downlink DL reference signal RS from the scheduling entity on a channel between the scheduling entity and the scheduled entity; obtaining channel state information (CSI) of the channel between the scheduling entity and the scheduled entity using the received DL RS; selecting an uplink resource associated with a random access procedure; multiplexing a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; sending the multiplexed information to the scheduling entity in the random access message on the selected uplink resource; wherein the random access message includes a Physical Uplink Shared Channel (PUSCH) for a Type 1 or Type 2 random access procedure, and wherein the multiplexed information is carried in the PUSCH; and wherein multiplexing the CSI report with the random access message includes: mapping the CSI report to a Media Access Control (MAC) control element (CE) of the PUSCH payload, and multiplexing the MAC CE with the random access message.
[0014] In another example, a method for wireless communication between a scheduled entity and a scheduling entity in a wireless communication network is disclosed, the method comprising, at the scheduled entity: receiving a downlink DL reference signal RS from the scheduling entity on a channel between the scheduling entity and the scheduled entity; using the received DL... The RS obtains Channel State Information (CSI) of the channel between the scheduling entity and the scheduled entity; selects an uplink resource associated with the random access procedure; multiplexes a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; sends the multiplexed information to the scheduling entity in the random access message on the selected uplink resource; receives a Random Access Response (RAR) from the scheduling entity after initiating the random access procedure, the RAR scheduling the PUSCH, wherein sending the multiplexed information includes sending the PUSCH in response to the RAR, wherein the random access message includes a Physical Uplink Shared Channel (PUSCH) for a Type 1 or Type 2 random access procedure, and wherein the multiplexed information is carried in the PUSCH; and wherein multiplexing the CSI report with the random access message includes: mapping the CSI report to a Media Access Control (MAC) control element (CE) of the PUSCH, and multiplexing the MAC CE with the PUSCH.
[0015] In another example, a scheduled entity within a wireless communication network is disclosed, comprising: a transceiver; a memory; and a processor communicatively coupled to the transceiver and the memory, wherein the processor and the memory are configured to: receive a downlink DL reference signal RS from the scheduling entity on a channel between the scheduling entity and the scheduled entity; and use the received DL... The RS obtains Channel State Information (CSI) of the channel between the scheduling entity and the scheduled entity; selects uplink resources associated with the random access procedure; multiplexes a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; sends the multiplexed information to the scheduling entity in the random access message on the selected uplink resource; receives a Random Access Response (RAR) from the scheduling entity after initiating the random access procedure, the RAR scheduling the PUSCH, wherein sending the multiplexed information includes: sending the PUSCH in response to the RAR; wherein the random access message includes a Physical Uplink Shared Channel (PUSCH) for a Type 1 or Type 2 random access procedure, and wherein the multiplexed information is carried in the PUSCH; and wherein sending the PUSCH in response to the RAR includes: decoding the uplink UL grant in the RAR, wherein the PUSCH includes a retransmitted PUSCH based on the UL grant retransmission.
[0016] In another example, a method for wireless communication between a scheduled entity and a scheduling entity in a wireless communication network is disclosed. The method includes, at the scheduled entity: receiving a downlink DL reference signal RS from the scheduling entity on a channel between the scheduling entity and the scheduled entity; obtaining channel state information (CSI) of the channel between the scheduling entity and the scheduled entity using the received DL RS; selecting an uplink resource associated with a random access procedure; multiplexing a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; transmitting the multiplexed information to the scheduling entity in the random access message on the selected uplink resource; measuring the received power of a beamforming reference signal from the scheduling entity; comparing the measured received power with a threshold; and transmitting the multiplexed information in response to the comparison.
[0017] In another example, a scheduled entity within a wireless communication network is disclosed, comprising: a transceiver; a memory; and a processor communicatively coupled to the transceiver and the memory, wherein the processor and the memory are configured to: receive a downlink DL reference signal RS from the scheduling entity on a channel between the scheduling entity and the scheduled entity; obtain channel state information (CSI) of the channel between the scheduling entity and the scheduled entity using the received DL RS; select an uplink resource associated with a random access procedure; multiplex a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; and send the multiplexed information to the scheduling entity in the random access message on the selected uplink resource; wherein the random access message includes a Physical Uplink Shared Channel (PUSCH) for a Type 1 or Type 2 random access procedure, and wherein the multiplexed information is carried in the PUSCH; and wherein multiplexing the CSI report with the random access message includes: mapping the CSI report to a Media Access Control (MAC) control element (CE) of the PUSCH payload, and multiplexing the MAC... The CE is multiplexed with the random access message.
[0018] In another example, a scheduled entity within a wireless communication network is disclosed, comprising: a transceiver; a memory; and a processor communicatively coupled to the transceiver and the memory, wherein the processor and the memory are configured to: receive a downlink DL reference signal RS from the scheduling entity on a channel between the scheduling entity and the scheduled entity; obtain channel state information (CSI) of the channel between the scheduling entity and the scheduled entity using the received DL RS; select an uplink resource associated with a random access procedure; multiplex a CSI report including the CSI with a random access message associated with the random access procedure to generate multiplexed information; transmit the multiplexed information to the scheduling entity in the random access message on the selected uplink resource; measure the received power of a beamforming reference signal from the scheduling entity; compare the measured received power with a threshold; and transmit the multiplexed information in response to the comparison.
[0019] These and other aspects of the invention will be more fully understood by reading the following detailed description. Other aspects, features, and embodiments of the invention will become apparent to those skilled in the art by reading the following description of specific exemplary embodiments in conjunction with the accompanying drawings. While features of the invention may be discussed with respect to certain embodiments and the drawings below, all embodiments of the invention may include one or more advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more such features may also be used according to the various embodiments of the invention discussed herein. Similarly, while exemplary embodiments may be discussed below as embodiments of devices, systems, or methods, it should be understood that such exemplary embodiments may be implemented in various devices, systems, and methods. Attached Figure Description
[0020] Figure 1 It is a schematic diagram based on some aspects of wireless communication systems;
[0021] Figure 2 It is a conceptual diagram based on examples of radio access networks from various aspects;
[0022] Figure 3 This is a schematic diagram illustrating the organization of radio resources in the air interface utilizing orthogonal frequency division multiplexing (OFDM) according to some aspects;
[0023] Figure 4 This is a block diagram illustrating a wireless communication system that supports beamforming and / or multiple-input multiple-output (MIMO) communication according to some aspects;
[0024] Figure 5 This is a block diagram illustrating the radio protocol architecture based on several aspects of the user and control planes;
[0025] Figure 6 This is a diagram illustrating an example of a four-step random access channel (RACH) process based on some aspects.
[0026] Figure 7 This is a diagram illustrating an example of a two-step RACH process based on some aspects;
[0027] Figure 8 This is a block diagram illustrating an example of a random access (RA) preamble that can be used in a two-step RACH process, depending on several aspects;
[0028] Figure 9 This is a diagram illustrating the signaling between the scheduling entity and the scheduling entity during the RACH process when the RA payload is decoded, according to some aspects.
[0029] Figure 10This is a diagram illustrating the signaling between the scheduled entity and the scheduling entity during the RACH process when only the RA preamble is decoded, according to some aspects.
[0030] Figure 11 This is a diagram illustrating the signaling between the scheduled entity and the scheduling entity during the RACH process when the CSI / CQI report is multiplexed with the RA preamble in the RA payload, according to some aspects.
[0031] Figure 12 This is a block diagram illustrating the RA payload based on several aspects, including the reuse of CSI / CQI reports;
[0032] Figure 13 This is another diagram illustrating the reuse of CSI / CQI reports based on some aspects;
[0033] Figure 14 This is a block diagram illustrating physical layer processing for multiplexing CSI / CQI reports with Media Access Control (MAC) layer control elements (CEs) according to some aspects;
[0034] Figure 15 This is a block diagram illustrating physical layer processing for multiplexing CSI / CQI reports with uplink control information (UCI) according to some aspects;
[0035] Figure 16 This is a diagram illustrating the signaling between the scheduled entity and the scheduling entity during the RACH process when only the RA preamble is decoded, according to some aspects, where CSI / CQI reports are multiplexed into the Physical Uplink Shared Channel (PUSCH) retransmission;
[0036] Figure 17 This is a block diagram illustrating the retransmission of PUSCH during the RACH process, including multiplexed CSI / CQI reports, based on several aspects.
[0037] Figure 18 This is another block diagram illustrating the retransmission of PUSCH during the RACH process, including multiplexed CSI / CQI reports, based on several aspects.
[0038] Figure 19 This is a diagram illustrating the signaling between the scheduled entity and the scheduling entity during the RACH process when the RA payload is decoded, according to some aspects, where the CSI / CQI report is multiplexed into the HARQ feedback to the RA response (RAR);
[0039] Figure 20 This is a block diagram showing the CSI / CQI multiplexed with HARQ feedback based on some aspects and mapped to the UCI transmitted on the Physical Uplink Control Channel (PUCCH);
[0040] Figure 21 This is another block diagram showing CSI / CQI transmitted on PUSCH and multiplexed with UCI carrying HARQ feedback, according to some aspects;
[0041] Figure 22 This is a diagram illustrating the signaling between the scheduled entity and the scheduling entity during the RACH process when a CSI / CQI report is multiplexed into a scheduled PUSCH transmission or a Radio Resource Control (RRC) connection establishment completion message, according to some aspects.
[0042] Figure 23 This is a block diagram illustrating an example of a hardware implementation of a scheduled entity using a processing system, based on some aspects; and
[0043] Figure 24 This is a flowchart illustrating an exemplary process for multiplexing CSI reports with random access procedure messages, according to some aspects. Detailed Implementation
[0044] The detailed description following, illustrated with reference to the accompanying drawings, is intended as a description of various configurations, and not as representing only configurations in which the concepts herein can be practiced. The detailed description includes specific details intended to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, to avoid obscuring these concepts, well-known structures and components are shown in block diagram form.
[0045] While aspects and embodiments have been described in this application by way of example, those skilled in the art will understand that additional implementations and use cases may arise in many different arrangements and scenarios. The innovations described herein can be implemented across many different platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, embodiments and / or uses may be implemented through integrated chip embodiments and other devices based on non-modular components (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, AI-enabled devices, etc.). While some examples may or may not be specific to a particular use case or application, a wide variety of applicability to the described innovations is possible. The scope of implementations can range from chip-level or modular components to non-modular, non-chip-level implementations, and further to aggregated, distributed, or OEM devices or systems incorporating one or more aspects of the innovation. In some practical settings, devices incorporating the described aspects and features may also need to include additional components and features for implementing and practicing the claimed and described embodiments. For example, the transmission and reception of wireless signals must involve multiple components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors (multiple), interleavers, adders / summers, etc.). The intent is that the innovations described herein can be implemented in a variety of devices, chip-level components, systems, distributed deployments, end-user devices, etc., varying in size, shape, and construction.
[0046] Various aspects of this disclosure relate to CSI measurement reporting from the UE to the base station. In NR Lightweight (New Radio-Lightweight) for low-cost radio links, link adaptation of the Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH) is useful for enhancing radio link coverage and spectral efficiency. Aperiodic and compressed Channel Quality Indicator / Channel State Information (CQI / CSI) reports can be transmitted in uplink control information (UCI) on the PUSCH, Physical Uplink Shared Channel (PUSCH), or piggyback on the PUSCH. This early reporting enhances the radio link faster with less overhead.
[0047] The various concepts presented throughout this disclosure can be implemented across multiple telecommunications systems, network architectures, and communication standards. Reference is now made to... Figure 1As a non-limiting illustrative example, reference is made to wireless communication system 100 to illustrate various aspects of this disclosure. Wireless communication system 100 includes three interacting domains: core network 102, radio access network (RAN) 104, and user equipment (UE) 106. With the aid of wireless communication system 100, UE 106 can perform data communication with external data network 110 (such as, but not limited to, the Internet).
[0048] RAN 104 can implement any suitable Radio Access Technology (RAT) to provide radio access to UE 106. As an example, RAN 104 can operate according to the 3rd Generation Partnership Project (3GPP) New Radio (NR) specification (commonly referred to as 5G). As another example, RAN 104 can operate under a hybrid of 5G NR and the Evolved Universal Terrestrial Radio Access Network (eUTRAN) standard (commonly referred to as LTE). 3GPP refers to this hybrid RAN as Next Generation RAN, or NG-RAN. In yet another example, RAN 104 can operate according to both LTE and 5G NR standards. Of course, many other examples can be utilized within the scope of this disclosure.
[0049] As shown in the figure, RAN 104 includes multiple base stations 108. Broadly speaking, a base station is a network element in a radio access network responsible for radio transmission to or reception from a UE in one or more cells. In different technologies, standards, or contexts, a base station may be referred to by those skilled in the art as a base transceiver station (BTS), radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), access point (AP), node B (NB), eNode B (eNB), gNode B (gNB), or some other suitable terminology. In the example where RAN 104 operates according to LTE and 5G NR standards, one of the base stations 108 may be an LTE base station, while another base station may be a 5G NR base station.
[0050] Radio access network 104 is further illustrated as supporting wireless communication for multiple mobile devices. In the 3GPP standard, a mobile device may be referred to as User Equipment (UE) 106, but may also be referred to by those skilled in the art as a mobile station (MS), subscriber station, mobile unit, subscriber unit, radio unit, remote unit, mobile device, radio device, wireless communication device, remote device, mobile subscriber station, access terminal (AT), mobile terminal, radio terminal, remote terminal, handphone, terminal, user agent, mobile client, client, or some other suitable term. UE 106 may be an apparatus for providing network service access to users. In an example where RAN 104 operates according to LTE and 5G NR standards, UE 106 may be an Evolved Universal Terrestrial Radio Access Network - New Radio Dual Connectivity (EN-DC) UE, capable of simultaneously connecting to both LTE and NR base stations to receive data packets from both.
[0051] In this document, a “mobile” device does not necessarily need to be capable of movement and can be stationary. The term mobile device or mobile equipment refers to a wide variety of devices and technologies. A UE may include multiple hardware structural components whose size, shape, and arrangement facilitate communication; these components may include antennas, antenna arrays, RF chains, amplifiers, one or more processors, etc., electrically coupled to each other. For example, some non-limiting examples of mobile devices include mobile phones, cellular phones, smartphones, Session Initiation Protocol (SIP) phones, laptops, personal computers (PCs), notebooks, netbooks, smartbooks, tablets, personal digital assistants (PDAs), and various embedded systems, such as those corresponding to the “Internet of Things”. A mobile device can also be an automobile or other vehicle, a remote sensor or actuator, a robot or robotic device, a satellite radio, a Global Positioning System (GPS) device, an object tracking device, a drone, a multi-helicopter, a quad-helicopter, a remote control device, a consumer and / or wearable device, such as glasses, wearable cameras, virtual reality devices, smartwatches, health or fitness trackers, digital audio players (e.g., MP3 players), cameras, game consoles, etc. Mobile devices can also be digital home or smart home devices, such as home audio, video and / or multimedia equipment, appliances, vending machines, smart lighting, home security systems, smart meters, etc. Mobile devices can also be smart energy devices, security devices, solar panels or solar arrays, municipal infrastructure equipment controlling electricity (such as smart grids), lighting, water, etc.; industrial automation and enterprise equipment; logistics management equipment; agricultural equipment; military defense equipment, vehicles, aircraft, ships, and weapons, etc. Furthermore, mobile devices can provide connected medical or telemedicine support, i.e., telehealth. Remote health devices can include remote health monitoring devices and remote health management devices, whose communications can be given priority processing or access over other types of information, for example, in terms of priority access for critical service data transmission and / or relevant QoS aspects of critical service data transmission.
[0052] Wireless communication between RAN 104 and UE 106 can be described as utilizing an air interface. Transmissions over the air interface from a base station (e.g., base station 108) to one or more UEs (e.g., UE 106) can be referred to as downlink (DL) transmissions. According to certain aspects of this disclosure, the term downlink can refer to point-to-multipoint transmissions initiated at a scheduling entity (further described below; e.g., base station 108). Another way to describe this scheme is to use the term broadcast channel multiplexing. Transmissions from a UE (e.g., UE 106) to a base station (e.g., base station 108) can be referred to as uplink (UL) transmissions. According to other aspects of this disclosure, the term uplink can refer to point-to-point transmissions initiated at a scheduled entity (further described below; e.g., UE 106).
[0053] In some examples, access to the air interface can be scheduled, where a scheduling entity (e.g., base station 108) allocates resources for communication between some or all devices and apparatuses within its service area or cell. In this disclosure, as further discussed below, the scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communication, UE 106 of the scheduled entity may utilize the resources allocated by the scheduling entity 108.
[0054] Base station 108 is not the only entity that can be used as a scheduling entity. That is, in some examples, a UE can act as a scheduling entity to schedule resources for one or more scheduled entities (e.g., one or more other UEs).
[0055] like Figure 1 As shown, scheduling entity 108 can broadcast downlink service 112 to one or more scheduled entities 106. In a broader sense, scheduling entity 108 is a node or device responsible for scheduling services in the wireless communication network (including downlink service 112, and in some examples, uplink service 116 from one or more scheduled entities 106 to scheduling entity 108). On the other hand, scheduled entity 106 is a node or device that receives downlink control information 114, which includes, but is not limited to, scheduling information (e.g., authorization), synchronization or timing information, or other control information from another entity in the wireless communication network (e.g., scheduling entity 108).
[0056] Furthermore, uplink and / or downlink control information and / or service information can be time-divided into frames, subframes, time slots, and / or symbols. As used herein, a symbol can refer to a time unit in an Orthogonal Frequency Division Multiplexing (OFDM) waveform where each subcarrier carries a resource element (RE). A time slot can carry 7 or 14 OFDM symbols. A subframe can refer to a duration of 1 millisecond. Multiple subframes or time slots can be grouped together to form a single frame or radio frame. Of course, these definitions are not mandatory, and any suitable scheme for organizing the waveform can be used, and the various time divisions of the waveform can have any suitable duration.
[0057] Typically, base station 108 may include a backhaul interface for communicating with the backhaul section 120 of a wireless communication system. Backhaul 120 provides a link between base station 108 and core network 102. Furthermore, in some examples, the backhaul network can provide interconnection between the individual base stations 108. Various types of backhaul interfaces can be used, such as a direct physical connection using any suitable transport network, a virtual network, etc.
[0058] The core network 102 may be part of the wireless communication system 100 and may be independent of the radio access technology used in the RAN 104. In some examples, the core network 102 may be configured according to a 5G standard (e.g., 5GC). In other examples, the core network 102 may be configured according to 4G Evolved Packet Core (EPC) or any other suitable standard or configuration.
[0059] Now for reference Figure 2 The diagram of RAN 200 is provided as an example, not a limitation. In some examples, RAN 200 can be combined with the above-described and Figure 1 The same as RAN 104 shown. The geographical area covered by RAN 200 can be divided into cellular areas (cells), which can be uniquely identified by user equipment (UE) based on an identifier broadcast from an access point or base station. Figure 2 Macro cells 202, 204, and 206, and small cell 208 are shown, each of which may include one or more sectors (not shown). A sector is a sub-area of a cell. All sectors within a cell are served by the same base station. Radio links within a sector can be identified by a single logical identifier belonging to that sector. In a cell divided into sectors, multiple sectors within the cell can be formed by antenna groups, each antenna responsible for communicating with UEs in a portion of the cell.
[0060] exist Figure 2 In the illustration, two base stations 210 and 212 are shown in cells 202 and 204; and a third base station 214 is shown as a remote radio head (RRH) 216 in control cell 206. That is, the base stations can have integrated antennas, or they can be connected to an antenna or RRH via a feeder cable. In the example shown, cells 202, 204, and 216 can be referred to as macrocells because base stations 210, 212, and 214 support cells with large sizes. Furthermore, base station 218 is shown in a small cell 208 (e.g., microcell, picocell, femtocell, home base station, home node B, home eNode B, etc.) that may overlap with one or more macrocells. In this example, cell 208 can be referred to as a small cell because base station 218 supports cells with relatively small sizes. Cell size can be determined based on system design and component constraints.
[0061] It should be understood that the radio access network 200 may include any number of wireless base stations and cells. Furthermore, relay nodes can be deployed to extend the size or coverage area of a given cell. Base stations 210, 212, 214, and 218 provide wireless access points to the core network for any number of mobile devices. In some examples, base stations 210, 212, 214, and / or 218 may be used in conjunction with those described above and Figure 1The base station / scheduling entity 108 shown is the same.
[0062] Within RAN 200, a cell may include UEs capable of communicating with one or more sectors of each cell. Furthermore, each base station 210, 212, 214, and 218 can be configured to provide access to the core network 102 (see [link to core network]) to all UEs within the corresponding cell. Figure 1 Access points. For example, UEs 222 and 224 can communicate with base station 210; UEs 226 and 228 can communicate with base station 212; UEs 230 and 232 can communicate with base station 214 via RRH 216; and UE 234 can communicate with base station 218. In some examples, UEs 222, 224, 226, 228, 230, 232, 234, 238, 240 and / or 242 can communicate with the access points described above and... Figure 1 The UE / scheduled entity 106 shown is the same.
[0063] In some examples, an unmanned aerial vehicle (UAV) 220 (which may be a drone or a quadcopter) can be a mobile network node and can be configured to act as a UE. For example, UAV 220 can operate within cell 202 by communicating with base station 210.
[0064] In a radio access network 200, the ability of a UE to communicate independently of its location while on the move is referred to as mobility. Various physical channels between the UE and the radio access network are typically used in the Access and Mobility Management Function (AMF, not shown). Figure 1 Under the control of the core network 102, the functions of establishing, maintaining and releasing security contexts can include Security Context Management (SCMF) for managing the security contexts of both control plane and user plane functions, and Security Anchor Function (SEAF) for performing authentication.
[0065] Radio access network 200 can utilize DL-based mobility or UL-based mobility to achieve mobility and handover (i.e., transferring the UE's connection from one radio channel to another). In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, the UE can monitor various parameters of the signal from its serving cell and various parameters of neighboring cells. Based on the quality of these parameters, the UE can maintain communication with one or more of the neighboring cells. During this period, if the UE moves from one cell to another, or if the signal quality from a neighboring cell exceeds the signal quality from the serving cell for a given amount of time, the UE can perform a handover or transfer from the serving cell to the neighboring (target) cell. For example, UE 224 (illustrated as a vehicle, although any suitable form of UE can be used) can move from a geographic area corresponding to its serving cell 202 to a geographic area corresponding to a neighboring cell 206. When the signal strength or quality from neighboring cell 206 exceeds the signal strength or quality from its serving cell 202 for a given amount of time, UE 224 can send a report message indicating this situation to its serving base station 210. In response, UE224 can receive a handover command and the UE can perform a handover to cell 206.
[0066] In a network configured for UL-based mobility, a UL reference signal from each UE can be used by the network to select a serving cell for each UE. In some examples, base stations 210, 212, and 214 / 216 can broadcast unified synchronization signals (e.g., unified primary synchronization signal (PSS), unified secondary synchronization signal (SSS), and unified physical broadcast channel (PBCH)). UEs 222, 224, 226, 228, 230, and 232 can receive the unified synchronization signal, derive the carrier frequency and time slot timing from the synchronization signal, and transmit uplink pilot or reference signals in response to the derived timing. The uplink pilot signal transmitted by a UE (e.g., UE 224) can be simultaneously received by two or more cells (e.g., base stations 210 and 214 / 216) within the radio access network 200. Each of these cells can measure the strength of the pilot signal, and the radio access network (e.g., one or more of base stations 210 and 214 / 216 and / or a central node within the core network) can determine a serving cell for UE 224. As UE 224 moves to access network 200 via radio, the network can continue to monitor the uplink pilot signals transmitted by UE 224. When the signal strength or quality of the pilot signals measured by a neighboring cell exceeds the signal strength or quality measured by the serving cell, network 200 can, with or without notifying UE 224, hand over UE 224 from the serving cell to a neighboring cell.
[0067] Although the synchronization signals transmitted by base stations 210, 212, and 214 / 216 can be uniform, the synchronization signals do not necessarily identify a specific cell. Instead, they can identify an area of multiple cells operating at the same frequency and / or the same timing. Using areas in 5G networks or other next-generation communication networks enables an uplink-based mobility framework and improves the efficiency of both the UE and the network by reducing the number of mobility messages that need to be exchanged between the UE and the network.
[0068] In various implementations, the air interface in the radio access network 200 can utilize licensed spectrum, unlicensed spectrum, or shared spectrum. Licensed spectrum provides exclusive use of a portion of the spectrum, typically achieved by a mobile network operator purchasing a license from a government regulatory agency. Unlicensed spectrum provides shared use of a portion of the spectrum without requiring a government-authorized license. While some technical rules are generally still required to access unlicensed spectrum, access is usually available to any operator or device. Shared spectrum can fall between licensed and unlicensed spectrum, where technical rules or restrictions may be required for spectrum access, but the spectrum may still be shared by multiple operators and / or multiple RATs. For example, a licensee of a portion of licensed spectrum can provide Licensed Shared Access (LSA) to share the spectrum with other parties, for example, by obtaining access under appropriate conditions determined by the licensee.
[0069] In some examples, access to the air interface can be scheduled, where a scheduling entity (e.g., a base station) allocates resources (e.g., time-frequency resources) for communication between some or all devices and apparatuses within its service area or cell. In this disclosure, as further discussed below, the scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communication, the UE or the scheduled entity utilizes the resources allocated by the scheduling entity.
[0070] A base station is not the only entity that can act as a scheduling entity. That is, in some examples, a UE can act as a scheduling entity, scheduling resources for one or more scheduled entities (e.g., one or more other UEs). In this example, sidelinks or other types of direct link signals can be transmitted directly between UEs without relying on scheduling or control information from another entity. For example, UE 238 is shown communicating with UEs 240 and 242. In some examples, UE 238 acts as the scheduling entity, while UEs 240 and 242 can act as scheduled entities.
[0071] UEs 238, 240, and 242 can communicate via direct links in device-to-device (D2D), peer-to-peer (P2P), vehicle-to-everything (V2X), and / or mesh networks. In the mesh network example, UEs 240 and 242 can optionally communicate directly with each other in addition to communicating with a scheduling entity (e.g., UE 238). In some examples, UE 238 may be a transmitting sidelink device that reserves resources on the sidelink carrier for transmitting sidelink signals to UEs 240 and 242 in the D2D or V2X network. Here, UEs 240 and 242 are each receiving sidelink devices. UEs 240 and 242 may further reserve additional resources on the sidelink carrier for subsequent sidelink transmissions.
[0072] In some examples, two or more UEs (e.g., UEs 226 and 228) within the coverage area of serving base station 212 can communicate with base station 212 using cellular signals and communicate with each other using sidelink signal 227 without relaying the communication through the base station. In this example, base station 212 or one or both of UEs 226 and 228 can act as a scheduling entity to schedule sidelink communication between UEs 226 and 228. For example, UEs 226 and 228 can transmit sidelink signal 227 within a vehicle-to-everything (V2X) network.
[0073] To achieve a low block error rate (BLER) while still maintaining a very high data rate in transmission over the radio access network 200, channel coding can be used. That is, wireless communication can typically utilize appropriate error-correcting block codes. In a typical block code, an information message or sequence is divided into code blocks (CBs), and then an encoder (e.g., a codec) at the transmitting device mathematically adds redundancy to the information message. Utilizing this redundancy in the encoded information message improves message reliability, making it possible to correct any bit errors that may occur due to noise.
[0074] In early 5G NR specifications, user data was encoded using quasi-cyclic low-density parity-check (LDPC) with two different base maps: one base map for large code blocks and / or high code rates, and the other for other cases. Control information and the Physical Broadcast Channel (PBCH) were encoded using polar coding based on nested sequences. For these channels, puncture, shortening, and repetition were used for rate matching.
[0075] However, those skilled in the art will understand that aspects of this disclosure can be implemented using any suitable channel code. Various implementations of the base station (e.g., scheduling entity) 108 and the UE (e.g., scheduled entity) 106 may include suitable hardware and capabilities (e.g., encoders, decoders, and / or CODECs) to utilize one or more of these channel codes for wireless communication.
[0076] The air interface in the radio access network 200 can utilize one or more duplex algorithms. Duplex refers to a point-to-point communication link where two endpoints can communicate bidirectionally. Full-duplex means that two endpoints can communicate simultaneously. Half-duplex means that only one endpoint can send information to the other endpoint at a time. In wireless links, full-duplex channels typically rely on physical isolation between the transmitter and receiver, as well as appropriate interference cancellation techniques. Full-duplex simulation is typically implemented by utilizing Frequency Division Duplex (FDD) or Time Division Duplex (TDD) to realize wireless links. In FDD, transmissions in different directions operate at different carrier frequencies. In TDD, transmissions in different directions on a given channel are separated using time-division multiplexing. That is, at certain times, the channel is dedicated to transmission in one direction, and at other times, the channel is dedicated to transmission in the other direction, where the direction can change very rapidly, for example, several times per time slot.
[0077] The air interface in the radio access network 200 can further utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of various devices. For example, the 5G NR specification utilizes Orthogonal Frequency Division Multiplexing (OFDM) with a cyclic prefix (CP) to provide multiple access for UL transmissions from UEs 222 and 224 to base station 210, and to provide multiplexing for DL transmissions from base station 210 to one or more UEs 222 and 224. Furthermore, for UL transmissions, the 5G NR specification provides support for Discrete Fourier Transform-Spread Spectrum-OFDM (DFT-s-OFDM) with CP (also known as Single-Carrier FDMA (SC-FDMA)). However, within the scope of this disclosure, multiplexing and multiple access are not limited to the above schemes and can be provided using Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Sparse Code Multiple Access (SCMA), Resource Spread Multiple Access (RSMA), or other suitable multiple access schemes. In addition, time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), sparse code multiplexing (SCM) or other suitable multiplexing schemes can be used to provide multiplexed DL transmission from base station 210 to UEs 222 and 224.
[0078] Various aspects of this disclosure will be described with reference to OFDM waveforms. Figure 3An example of an OFDM waveform is schematically illustrated. Those skilled in the art will understand that various aspects of this disclosure can be applied to SC-FDMA waveforms in substantially the same manner as described below. That is, although some examples of this disclosure may focus on OFDM links for clarity, it should be understood that the same principles can also be applied to SC-FDMA waveforms.
[0079] Now for reference Figure 3 The diagram shows an unfolded view of an exemplary DL subframe 302, which illustrates the OFDM resource grid. However, as those skilled in the art will readily understand, the PHY transport structure for any particular application can differ from the example described herein, depending on numerous factors. Here, time is in the horizontal direction, in OFDM symbols; frequency is in the vertical direction, in subcarriers.
[0080] Resource grid 304 can be used to schematically represent the time-frequency resources of a given antenna port. That is, in a multiple-input multiple-output (MIMO) implementation with multiple available antenna ports, multiple resource grids 304 can be used for communication. Resource grid 304 is divided into multiple resource elements (REs) 306. An RE is 1 subcarrier × 1 symbol, which is the smallest discrete part of the time-frequency grid and contains a single complex quantity representing data from a physical channel or signal. Depending on the modulation used in a particular implementation, each RE can represent one or more information bits. In some examples, a block of REs may be referred to as a physical resource block (PRB) or more simply as a resource block (RB) 308, which contains any suitable number of consecutive subcarriers in the frequency domain. In one example, an RB may include 12 subcarriers, the number of which is independent of the parameter set used. In some examples, depending on the parameter set, an RB may include any suitable number of consecutive OFDM symbols in the time domain. In this disclosure, it is assumed that a single RB such as RB 308 corresponds exactly to a single communication direction (transmit or receive for a given device).
[0081] UEs typically utilize only a subset of resource grid 304. An RB can be the smallest unit of resource that can be allocated to a UE. Therefore, the more RBs scheduled for a UE and the more advanced the modulation scheme selected for the air interface, the higher the UE's data rate.
[0082] In this illustration, RB 308 is shown occupying less than the entire bandwidth of subframe 302, with some subcarriers shown above and below RB 308. In a given implementation, subframe 302 can have a bandwidth corresponding to any number of one or more RB 308s. Furthermore, in this illustration, RB 308 is shown occupying less than the entire duration of subframe 302, although this is merely one possible example.
[0083] Each 1 ms subframe 302 may include one or more adjacent time slots. Figure 4 In the example shown, as an illustrative example, a subframe 302 includes four time slots 310. In some examples, time slots can be defined based on a specified number of OFDM symbols with a given cyclic prefix (CP) length. For example, a time slot may include 7 or 14 OFDM symbols with a nominal CP. Other examples may include micro-time slots with shorter durations (e.g., one or two OFDM symbols). In some cases, these micro-time slots may be transmitted using resources scheduled for ongoing time slot transmissions for the same or different UEs.
[0084] An enlarged view of a time slot in time slot 310 shows time slot 310 including control region 312 and data region 314. Typically, control region 312 may carry a control channel (e.g., PDCCH), and data region 314 may carry a data channel (e.g., PDSCH or PUSCH). Of course, a time slot may contain all DL, all UL, or at least one DL portion and at least one UL portion. Figure 3 The simple structure shown is merely exemplary and can utilize different time slot structures, and can include one or more of each of the control region and data region(s).
[0085] although Figure 3 Although not shown, each RE 306 within RB 308 can be scheduled to carry one or more physical channels, including control channels, shared channels, data channels, etc. Other REs 306 within RB 308 can also carry pilot or reference signals, including but not limited to demodulation reference signals (DMRS), control reference signals (CRS), CSI-RS, or probe reference signals (SRS). These pilot or reference signals can be provided to the receiving equipment to perform channel estimation for the corresponding channels, which enables coherent demodulation / detection of the control and / or data channels within RB 308.
[0086] In DL transmission, the transmitting device (e.g., a scheduling entity) may allocate one or more REs 306 (e.g., within control area 312) to one or more scheduled entities to carry DL control information including one or more DL control channels (such as: PBCH; Physical Control Format Indicator Channel (PCFICH); Physical Hybrid Automatic Repeat Request (HARQ) Indicator Channel (PHICH); and / or Physical Downlink Control Channel (PDCCH), etc.). The transmitting device may also allocate one or more REs 306 to carry other DL signals, such as: DMRS; Phase Tracking Reference Signal (PT-RS); Channel State Information-Reference Signal (CSI-RS); Primary Synchronization Signal (PSS); and Secondary Synchronization Signal (SSS).
[0087] Synchronization signals PSS and SSS, and in some examples PBCH and PBCH DMRS, can be transmitted in a synchronization signal block (SSB) comprising four consecutive OFDM symbols, numbered in ascending order from 0 to 3 via time indexing. In the frequency domain, the SSB can be extended over 240 consecutive subcarriers, where the subcarriers are numbered in ascending order from 0 to 239 via frequency indexing. Of course, this disclosure is not limited to this particular SSB configuration. Within the scope of this disclosure, other non-limiting examples may utilize more or fewer than two synchronization signals; one or more supplementary channels may be included in addition to PBCH; PBCH may be omitted; and / or different numbers of symbols and / or discontinuous symbols may be used for the SSB.
[0088] The PBCH may also include a Master Information Block (MIB), which contains various system information and parameters for decoding the System Information Block (SIB). The SIB may be, for example, SystemInformationType1 (SIB1), which may include various additional system information. Examples of system information may include, but are not limited to, subcarrier spacing, system frame number, cell prohibition indication, a list of common control resource sets (CoreSets) (e.g., PDCCH CoreSet0 or CoreSet1), a list of common search spaces, the search space of SIB1, the paging search space, the random access search space, and uplink configuration information.
[0089] PCFICH provides information to assist the receiving device in receiving and decoding PDCCH. PDCCH carries downlink control information (DCI), including but not limited to power control commands, scheduling information, grants, and / or RE allocations for DL and UL transmissions. PHICH carries HARQ feedback transmissions, such as acknowledgments (ACK) or negative acknowledgments (NACK). HARQ is a technique well-known to those skilled in the art, where the integrity of packet transmissions can be checked at the receiving side to ensure accuracy, for example, using any suitable integrity checking mechanism, such as checksums or cyclic redundancy checks (CRC). If the integrity of the transmission is acknowledged, an ACK can be sent; if not, a NACK can be sent. In response to a NACK, the transmitting device can send a HARQ retransmission, which enables follow-up merging, incremental redundancy, etc.
[0090] In UL transmissions, the transmitting device (e.g., the scheduled entity) may utilize one or more RE 306s to carry UL control information including one or more UL control channels (such as the Physical Uplink Control Channel (PUCCH) and / or the Random Access Channel (RACH)). For example, during initial access to the uplink, the RACH may be used in the random access process. UL control information may include various packet types and categories, including pilots, reference signals, and information configured to enable or assist in decoding uplink data transmissions. For example, UL control information may include DMRS or SRS. In some examples, the control information may include a scheduling request (SR), i.e., a request to a scheduling entity to schedule uplink transmissions. Here, in response to an SR transmitted on the control channel, the scheduling entity may send downlink control information that can schedule resources for uplink packet transmissions. UL control information may also include HARQ feedback, Channel State Feedback (CSF), or any other suitable UL control information. UL transmissions can be licensed (i.e., licensed transmissions delivered using DCI) or unlicensed, including Type 1 (e.g., based solely on RRC configuration without any L1 signaling) or Type 2 (e.g., based on RRC configuration and L1 signaling for activation / deactivation).
[0091] In addition to control information, one or more REs 306 can be allocated for user data or service data (e.g., within data area 314). This service can be carried on one or more service channels (e.g., PDSCH for DL transmissions; or Physical Uplink Shared Channel (PUSCH) for UL transmissions). In some examples, one or more REs 306 within data area 314 can be configured to carry a System Information Block (SIB) (e.g., SIB1) that enables access to a given cell.
[0092] These physical channels are typically multiplexed and mapped to transport channels for processing at the Media Access Control (MAC) layer. The transport channel carries blocks of information called transport blocks (TBs). The transport block size (TBS), which corresponds to the number of information bits, can be a controlled parameter based on the modulation and coding scheme (MCS) and the number of redundancies (RBs) in a given transmission.
[0093] The above reference Figure 1-3 The channels or carriers described are not necessarily all channels or carriers that can be used between the scheduling entity and the scheduled entity. Those skilled in the art will recognize that other channels or carriers, such as other service, control, and feedback channels, may be used in addition to those shown.
[0094] In some aspects of this disclosure, the scheduling entity and / or the scheduled entity can be configured for beamforming and / or multiple-input multiple-output (MIMO) techniques. Figure 4 An example of a wireless communication system 400 supporting beamforming and / or MIMO is shown. In the MIMO system, transmitter 402 includes multiple transmit antennas 404 (e.g., N transmit antennas), and receiver 406 includes multiple receive antennas 408 (e.g., M receive antennas). Therefore, there are N × M signal paths 410 from transmit antennas 404 to receive antennas 408. Each of transmitter 402 and receiver 406 can be implemented in, for example, a scheduling entity, a scheduled entity, or any other suitable wireless communication device.
[0095] The use of this multi-antenna technology enables wireless communication systems to leverage the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing can be used to simultaneously transmit different data streams on the same time-frequency resources, also known as layers. Data streams can be sent to a single UE to increase the data rate, or to multiple UEs to increase the overall system capacity; the latter is known as multi-user MIMO (MU-MIMO). This is achieved by spatially precoding each data stream (i.e., multiplying the data stream by different weights and phase shifts) and then transmitting each spatially precoded stream through multiple transmit antennas on the downlink. The spatially precoded data streams arrive at (multiple) UEs with different spatial signatures, allowing each of the (multiple) UEs to recover one or more data streams destined for that UE. On the uplink, each UE transmits a spatially precoded data stream, enabling the base station to identify the source of each spatially precoded data stream.
[0096] The number of data streams or layers corresponds to the transmission rank. Typically, the rank of a MIMO system is limited by the number of transmit or receive antennas (404 or 408), whichever is lower. Furthermore, channel conditions at the UE and other considerations, such as available resources at the base station, can also affect the transmission rank. For example, the rank (and the number of data streams) allocated to a particular UE on the downlink can be determined based on the rank indicator (RI) sent from the UE to the base station. The RI can be determined based on the antenna configuration (e.g., the number of transmit and receive antennas) and the signal-to-interference-noise ratio (SINR) measured on each of the receive antennas. The RI can indicate, for example, the number of layers that can be supported under the current channel conditions. The base station can use the RI, along with resource information (e.g., available resources and the amount of data to be scheduled for the UE), to allocate transmission ranks to the UE.
[0097] In one example, such as Figure 4 As shown, rank-2 spatial multiplexing transmission on a 2x2 MIMO antenna configuration will send a data stream from each transmit antenna 404. Each data stream arrives at each receive antenna 408 along a different signal path 410. The receiver 406 can then reconstruct the data stream using the received signals from each receive antenna 408.
[0098] Beamforming is a signal processing technique that can be used at transmitter 402 or receiver 406 to shape or manipulate an antenna beam (e.g., a transmit beam or a receive beam) along a spatial path between transmitter 402 and receiver 406. Beamforming can be achieved by combining signals transmitted via antennas 404 or 408 (e.g., antenna elements of an antenna array module) such that some signals experience constructive interference while others experience destructive interference. To generate the desired constructive / destructive interference, transmitter 402 or receiver 406 can apply amplitude and / or phase shifts to the signals transmitted or received from each of the antennas 404 or 408 associated with transmitter 402 or receiver 406.
[0099] In some examples, to select a specific beam for communication with the UE, the base station can transmit reference signals, such as SSBs or Channel State Information Reference Signals (CSI-RS), on each of multiple beams (SSB beams) in a beam-scanning manner. The UE can measure the Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), or SINR on each beam and send a beam measurement report to the base station indicating the RSRP of each measured beam. The base station can then select a specific beam for communication with the UE based on the beam measurement report. In other examples, when the channel is reciprocal, the base station can derive a specific beam for communication with the UE based on uplink measurements of one or more uplink reference signals, such as Sounding Reference Signals (SRS).
[0100] To access a cell, a UE can perform a random access procedure on the Physical Random Access Channel (PRACH). The UE can identify a random access search space from SIB1, including PRACH resources for initiating the RACH procedure. For example, after the UE acquires the cell and determines the occurrence of a RACH opportunity (e.g., PRACH resources) after reading the SSB and SIB1, a random access procedure can begin. The SSB provides initial system information (SI), and SIB1 (and other SIB blocks) provide the remaining minimum SI (RMSI). For example, the PBCH MIB of the SSB can carry the first part of the SI required for the UE to access the network. SIBs (e.g., SIB1 and SIB2) can carry the RMSI required for the UE to access the network.
[0101] The RACH procedure can be executed in various scenarios, such as loss of uplink synchronization, lack of available PUCCH resources, scheduling request failure, and other use cases. Furthermore, the RACH procedure can be contention-based or contention-free, and can include two-step RACH procedures (contention-based or contention-free), three-step RACH procedures (contention-free), or four-step RACH procedures (contention-based).
[0102] Such as Figure 1 The radio access network 104 and / or shown Figure 2 The radio protocol architecture of the radio access network 200 shown can take various forms depending on the specific application. Figure 5 An example of the radio protocol architecture for the user and control planes is shown.
[0103] like Figure 5As shown, the wireless protocol architecture of the UE and base station consists of three layers: Layer 1 (L1), Layer 2 (L2), and Layer 8 (L8). L1 is the lowest layer and implements various physical layer signal processing functions. L1 will be referred to here as physical layer 506. L2 508 is located above physical layer 506 and is responsible for the link between the UE and the base station on physical layer 506.
[0104] In the user plane, L2 layer 508 includes a Media Access Control (MAC) layer 510, a Radio Link Control (RLC) layer 512, a Packet Data Convergence Protocol (PDCP) layer 514, and a Service Data Adaptation Protocol (SDAP) layer 516, which terminate at the base station on the network side. Although not shown, the UE may have several upper layers above L2 layer 508, including at least one network layer (e.g., an IP layer and a User Data Protocol (UDP) layer) and one or more application layers, wherein the network layer terminates at the user plane function (UPF) on the network side.
[0105] SDAP layer 516 provides mapping between 5G core (5GC) Quality of Service (QoS) streams and data radio bearers, and performs QoS stream ID marking in downlink and uplink packets. PDCP layer 514 provides packet sequence numbering, ordered packet delivery, retransmission of PDCP Protocol Data Units (PDUs), and transmission of upper-layer data packets to lower layers. PDUs can include, for example, Internet Protocol (IP) packets, Ethernet frames, and other unstructured data (i.e., Machine Type Communication (MTC), hereinafter collectively referred to as "packets"). PDCP layer 514 also provides header compression for upper-layer data packets to reduce radio transmission overhead, security through encryption of data packets, and integrity protection for data packets. PDCP context can indicate whether PDCP replication is used for unicast connections.
[0106] RLC layer 512 provides segmentation and reassembly of upper-layer data packets, error correction via Automatic Repeat Request (ARQ), and sequence numbering independent of PDCP sequence numbering. The RLC context can indicate whether an acknowledged mode (e.g., using a reordering timer) or an unacknowledged mode is used for RLC layer 512. MAC layer 510 provides multiplexing between logical and transport channels. MAC layer 510 is also responsible for allocating various radio resources (e.g., resource blocks) within a cell among UEs and for HARQ operations. The MAC context can implement, for example, HARQ feedback schemes, resource selection algorithms, carrier aggregation, beam failure recovery, or other MAC parameters for unicast connections. Physical layer 506 is responsible for transmitting and receiving data on physical channels (e.g., within time slots). The PHY context can indicate the transmission format and radio resource configuration (e.g., bandwidth portion (BWP), parameter set, etc.) for unicast connections.
[0107] In the control plane, the radio protocol architecture for the UE and base station is essentially the same for L1 506 and L2 508, except that there is no SDAP layer and no header compression function for the control plane. The control plane also includes the Radio Resource Control (RRC) layer 518 in L8 and the higher Non-Access Stratum (NAS) layer 520. RRC layer 518 is responsible for establishing and configuring signaling radio bearers (SRBs) and data radio bearers (DRBs) between the base station and the UE, paging initiated by 5GC or NG-RAN, and broadcasting system information related to the Access Stratum (AS) and Non-Access Stratum (NAS). RRC layer 518 is also responsible for QoS management, mobility management (e.g., handover, cell selection, inter-RAT mobility), UE measurement and reporting, and security functions. NAS layer 520 terminates at the AMF in the core network and performs various functions such as authentication, registration management, and connection management.
[0108] Figure 6 This is a diagram illustrating an example of a four-step random access channel (RACH) process 600 according to some aspects. The scheduling entity 602 may correspond to, for example... Figure 1 and / or Figure 2 Any scheduling entity shown in the gNB or scheduling entity. Furthermore, the scheduled entity 604 may correspond to, for example... Figure 1 and / or Figure 2 The UE shown or any of the scheduled entities shown.
[0109] As described above, when the scheduled entity 604 first receives the SSB, RS, and RACH configuration 606, Figure 6The random access procedure 600 shown is initiated. The scheduled entity 604 can then randomly select a preamble from the set of available preambles within the cell served by the scheduling entity 602, as indicated in the RACH configuration, and send the selected preamble to the scheduling entity 602 in a RACH preamble message 608 (msg1). In this example, the scheduled entity 604 can select from 64 possible preamble sequences to include in the RACH preamble message 606. msg1 608 can be transmitted by the scheduled entity 604 on the selected PRACH resource using power ramping. The selected PRACH resource can include supplementary uplink resources or normal uplink resources. Here, supplementary uplink resources include resources at lower frequencies than normal uplink resources. Therefore, supplementary uplink resources and uplink resources each correspond to different respective uplink frequency bands. msg1 608 can also be transmitted on a beam selected by the scheduled entity 604 based on beam measurements (e.g., RSRP / RSRQ / SINR) performed by the scheduled entity 604. This beam may correspond to, for example, an SSB beam.
[0110] If scheduling entity 602 successfully detects the preamble, it sends a Random Access Response (RAR) message 610 (msg2) including PDCCH and PDSCH to scheduled entity 604. If msg2 (RAR) 610 is not received within the RAR window, scheduled entity 604 can retransmit msg1 608 with power boost. msg2 610 (PDCCH + PDSCH) includes the identifier of the preamble sent by scheduled entity 604, timing advance (TA), the Temporary Cell Radio Network Temporary Identifier (TC-RNTI) or Random Access (RA) RNTI for scheduled entity 604, and the authorization of the allocated uplink (UL) resources. The PDCCH in msg2 610 can be scrambled with RA-RNTI, which is a function of the RACH timing (RO) (e.g., the time-frequency resources allocated for RACH msg1) used by scheduled entity 604 to send msg1 608. The Media Access Control element (MAC-CE) within the PDSCH provides acknowledgment of the reception of msg1 608 and UL authorization. To receive msg2 610, the scheduled entity 604 can monitor DCI 1_0 for the PDCCH scrambled with RA-RNTI corresponding to the RO used by the scheduled entity 604 to transmit msg1 608, and if detected, proceed with PDSCH decoding. Upon receiving RAR message 610, the scheduled entity 604 compares the preamble ID with the preamble sent by the scheduled entity in the RACH preamble message 608. If the preamble ID matches the preamble sent in the RACH preamble message 608, the scheduled entity 604 applies timing advance and begins the contention resolution process.
[0111] Since the preamble can be randomly selected by the scheduled entity, a collision may occur between the two scheduled entities if another scheduled entity selects the same preamble in the same RO. Any collision can then be resolved using a contention resolution process. During contention resolution, scheduled entity 604 transmits an uplink message (msg3) 612, such as a PUSCH, on the Common Control Channel (CCCH) using the TA in the PDSCH in msg2 610 and the allocated uplink resources. In the example, uplink message 612 is a Layer 2 / Layer 3 (L2 / L3) message, such as a Radio Resource Control (RRC) Connection Request message. Uplink message 612 includes the identifier (scheduled entity ID) of scheduled entity 604 used by the scheduling entity in resolving any collision. Although other scheduled entities may use the TA and allocated uplink resources to transmit conflicting uplink messages, these conflicting uplink messages will likely not be successfully decoded at the scheduling entity because they are transmitted with TAs not intended for those scheduled entities.
[0112] After successfully decoding the uplink message, scheduling entity 602 sends a contention resolution message 614 (msg4) to scheduled entity 604. Contention resolution message 614 can be, for example, an RRC connection establishment message. Furthermore, contention resolution message 614 includes the identifier of scheduled entity 604 received in uplink message 612. When scheduled entity 604 receives its own identifier in contention resolution message 614, it determines that the random access procedure was successful and completes the RRC connection establishment procedure. Any other scheduled entity that receives an RRC connection establishment message with the identifier of scheduled entity 604 will infer that the random access procedure failed and reinitialize the random access procedure. As mentioned above, msg4 614 can have a PDCCH control component and a PDSCH payload component.
[0113] Once the contention is resolved, data can be transferred between the scheduled entity 604 and the scheduling entity 602 by exchanging payloads in the PUSCH and PDSCH messages. The scheduled entity can then send a HARQ response (e.g., ACK / NACK) for the PDSCH payload in, for example, the PUCCH message 616.
[0114] Figure 7 This is a diagram illustrating an example two-step RACH process based on some aspects, where a four-step process 600 can be compressed into... Figure 7 The two-step random access procedure 700 is shown. The two-step random access procedure 700 reduces the overhead and latency associated with control signaling by removing transmissions in each direction between the scheduled entity 704 and the scheduling entity 702 (e.g., gNB). Figure 6In contrast, the two-step random access procedure 700 uses the same SSB, RS, and RACH configuration messages 706 as the four-step RA procedure described above. These two steps begin with the scheduling entity 704 transmitting msgA 708, which includes the RACH preamble message and uplink message of the contention-based random access procedure shown in 600. Here, the uplink message can be a scheduled PUSCH transmission sent via PUSCH resources, and the RACH preamble message can be sent via the selected PRACH resource. The scheduling entity 702 responds with a single message (msgB 710) including a random access response and a contention resolution message, similar to msg4 in the four-step procedure described above. This message includes PDCCH and PDSCH. The scheduled entity 704 responds to msgB 712 with HARQACK / NACK in the PUCCH message.
[0115] Figure 8 This is a block diagram illustrating an example of a random access (RA) preamble 802 that can be used in a two-step RACH process, depending on some aspects. Here, the RA preamble 802 is shown as msgA, which can be combined in a similar manner to the above. Figure 7 The msgA (708) is described. In this example, the RA preamble 802 includes the msgA preamble 804, which includes PRACH 812 and a guard slot 814. Following the msgA preamble is the msgA payload 806, which includes DMRS / PUSCH 818 and a configured time period T. GP The protection period 820 of 810. The RA preamble 802 may include the TxG time slot 816 between the msgA preamble 804 and the msgA payload, for use in the configured time slot T. gap Transmitter antenna gain information on the 808.
[0116] Figure 9 This is a diagram illustrating the signaling 900 between scheduling entity 904 and scheduling entity 902 during the RACH process when the RA payload (msgA) is decoded, according to some aspects. Figure 9 Examples combined with the above Figure 7The two-step RACH process described is similar in that the scheduled entity 904 receives the same SSB, RS, and RACH configuration messages in 906. The scheduled entity 904 can then select a preamble from the set of available preambles within the cell served by the scheduling entity 902, as indicated in the RACH configuration, and send the selected preamble to the scheduling entity 902 in msgA, which includes the PRACH preamble 908 and the PUSCH payload transmission 910. The PRACH preamble in msgA can be separate from the four-step RACH preamble, but can be sent in the same PRACH timing (RO) as the four-step RACH preamble or in a separate RO. The PUSCH payload transmission 910 can be configured for PUSCH timings (PO) across multiple symbols and PRBs, with optional guard periods and guard bands between consecutive POs.
[0117] In block 912, scheduling entity 902 can decode the msgA payload and send a random access response (RAR) msgB 914, 916 to the UE with the contention resolution ID of msgA. This RAR may include the detected preamble ID, timing advance command, temporary radio network temporary identifier C-RNTI (or msgB-RNTI), uplink grant for scheduling PUSCH, and successRAR (916) on PDSCH. In block 918, the scheduled entity 904 decodes the successRAR and sends an acknowledgment HARQ ACK 920 for msgB to scheduling entity 902 via PUCCH after contention resolution, thereby establishing the successful completion of the RA procedure in 922.
[0118] Figure 10 This diagram illustrates the signaling 1000 between scheduling entity 1004 and scheduling entity 1002 during the RACH process, when only the RA preamble is decoded, according to some aspects. Figure 1000 and Figure 9 Similar to Figure 900, the scheduled entity 1004 receives SSB, RS, and RACH configuration messages in 1006. The scheduled entity 1004 can select a preamble from the set of available preambles within the cell served by the scheduling entity 1002, as indicated in the RACH configuration, and send the selected preamble to the scheduling entity 1002 in msgA, where msgA includes the PRACH preamble 1008 and the PUSCH payload transmission 1010.
[0119] In box 1012, the scheduling entity may only detect the msgA preamble (i.e., not the PUSCH payload), causing scheduling entity 1002 to send msgB-RNTI to scheduled entity 1004 via PDCCH 1014 and fallbackRAR to scheduled entity 1004 via msgB PDSCH, and may also include RAPID (Random Access Preamble ID) and uplink grant for MsgAPUSCH retransmission. In box 1018, the scheduled entity decodes the fallbackRAR and falls back to a four-step RACH with msg3 transmission (retransmission of MsgA PUSCH) in box 1020. In box 1022, scheduling entity 1002 decodes msg3 and sends msg4 provisional C-RNTI (TC-RNTI) via PDCCH resources in box 1024, and msg4 contention resolution (CR) via PDSCH resources in box 1026. In box 1028, the scheduled entity 1004 decodes the CR and sends back an acknowledgment HARQ ACK 1030 via the PUCCH resource, thus successfully completing the RA in 1032.
[0120] In some examples, the scheduled entity can operate in an environment supporting reduced-capability NR devices (also known as "NR Lightweight"). Compared to what conventional NR devices offer, NR Lightweight devices can be configured with lower device complexity and reduced power consumption, while having higher requirements for data rate and latency compared to, for example, LTE Machine Type Communication (MTC) and Narrowband Internet of Things (NB-IoT). Regarding reduced device complexity, NR Lightweight devices can be configured to support a reduced number of device-side TX / RX antennas, a reduced minimum required device bandwidth, and / or support devices capable of only half-duplex operation (no simultaneous TX / RX) in paired spectrum. Regarding reduced device power consumption, NR Lightweight devices can be configured with reduced PDCCH monitoring complexity by reducing the number of blind decodes required and extending discontinuous reception (DRX) functionality. Those skilled in the art will understand that the examples in this disclosure are applicable to applications utilizing NR Lightweight, although they can also be applied to conventional NR configurations.
[0121] NR light devices are configured to perform a two-step or four-step RACH procedure in the initial bandwidth portion (BWP) or active BWP. This technique can improve the coverage, power, and spectral efficiency of NR light devices by utilizing link adaptation, for example, based on CSI / CQI reports, during transmission / reception in the initial or active BWP. In some examples, this disclosure discloses using early reporting of CSI and / or CQI during the RACH procedure to improve performance. In some examples, CSI / CQI reports can be triggered by, for example, downlink control information (DCI) or random access response (RAR) of msgB in a two-step RACH. CSI / CQI reports can be multiplexed with the payload of msgA, HARQ feedback to msgB or successRAR, or retransmission of the msgA payload scheduled by msgB or fallbackRAR. Those skilled in the art will understand that the techniques and methods disclosed herein can also be used in a four-step RACH procedure and can be used by NR UE devices.
[0122] Figure 11This diagram illustrates signaling 1100 between scheduled entity 1104 and scheduling entity 1102 during the RACH process when CSI / CQI reports are multiplexed in the RA (msgA) payload, according to some aspects. Similar to the example above, scheduled entity 1104 receives the SSB, RS, and RACH configuration in 1106. In this example, before scheduled entity 1004 initiates a msgA transmission in a two-step RACH process (contention-free or contention-based), it should first obtain RACH configuration information from system information or dedicated RRC signaling. In some examples, the scheduled entity measures the Reference Signal Received Power (RSRP) of the SSB, CSI-RS, or other reference signals. After obtaining the measurement, the scheduled entity can then select a specific msgA PUSCH configuration and determine the PRACH preamble and PUSCH resources for the msgA transmission. Therefore, the scheduled entity 1104 can multiplex the CSI / CQI report with the msgA PUSCH (e.g., CCCH message, C-RNTI, user plane / control plane data, etc.) (as shown by the dashed circle in the figure) and select an appropriate msgA PUSCH configuration (e.g., transport block size (TBS)) to send the msgA preamble 1108 and the msgA payload 1110 containing the multiplexed CSI / CQI report. In one example, the scheduled entity maps the CSI / CQI report to a MAC-CE, which is multiplexed with other MAC-CEs sent by the msgA PUSCH (1110). Upon receiving the multiplexed signal, the scheduling entity responds with a RAR msgB 1112. In some examples, multiplexing the CSI report with the random access message is accomplished by puncturing the resource element RE of the PUSCH or by rate matching.
[0123] exist Figure 11 In the example, the triggering of CSI / CQI reports in the scheduled entity can be based on one or more criteria configured by the network and signaled in the SI / RRC. For example, the triggering can be based on an RSRP threshold configured by the network. If the RSRP measurement is equal to or greater than the threshold, a CSI / CQI report is sent. Otherwise, no CSI / CQI report is sent. Alternatively or additionally, the triggering can be based on the Transport Block Size (TBS) of msgA and / or the buffer state of the scheduled entity. If the buffered data size plus the CSI / CQI report size is equal to or less than the TBS of msgA, a CSI / CQI report is sent. Otherwise, no CSI / CQI report is sent.
[0124] Figure 12This is a block diagram 1200 illustrating an RA payload (msgAPUSCH 1202) that includes a reused CSI / CQI report, according to several aspects. In this example, msgAPUSCH 1202 includes a CSI / CQI report 1204, which is mapped to a MAC-CE and reused with other MAC-CEs of the msgAP payload 1206 (see [link to diagram]). Figure 14 ). Figure 13 This is another block diagram 1300 illustrating the multiplexing of CSI / CQI report 1304 according to some aspects. In this example, CSI / CQI report 1304 is mapped to uplink control information (UCI), where UCI can be multiplexed with other MAC-CEs of msgA PUSCH 1302 and msgA payload 1306 (see [link to diagram]). Figure 15 In some examples, CSI reports and random access messages are multiplexed by puncturing the resource elements (REs) of the PUSCH or by rate matching. In some examples, UCI piggybacking can be used in CSI / CQI reports 1304, where the scheduled entity receives a downlink control message that may include an authorization for an uplink shared channel (e.g., a physical uplink shared channel (PUSCH)) and may also include an indication of the component carriers (CCs) used to transmit the UCI. In some cases, the CC scheduled for the uplink shared channel is an authorized CC, and the scheduled entity can determine to transmit the piggybacked UCI in a single payload using the shared channel. In other cases, the CC scheduled for the uplink shared channel is not an authorized CC, and the scheduled entity can then utilize either a primary CC (PCC) or a secondary CC (SCC) used for uplink transmission to piggyback the UCI.
[0125] In some examples, when a scheduled entity reports CSI / CQI in msgAPUSCH, it can measure the SSB, CSI-RS, or other RS sent along with RACH configuration information (SI or RRC signaling). The mechanism used to trigger a scheduled entity to report CSI / CQI in msgAPUSCH can be based on one or more criteria configured by the network, and will be discussed in further detail below.
[0126] Figure 14 This is a block diagram 1400 illustrating physical layer processing for multiplexing CSI / CQI reports with Media Access Control (MAC) layer control elements (CEs) according to some aspects. In this example, the CSI / CQI report is multiplexed with other NAC-CEs of msgA 1402 to form msgA payload 1404, similar to the combination described above. Figure 12The msgA payload 1202 is described. Then, in box 1404, channel coding and rate matching are performed on the msgA payload 1404. In some examples, channel coding may include additional transport block CRC to provide error detection, followed by low-density parity-check (LDPC) basemap selection. The msgA payload 1404 can be segmented into code blocks and code block CRC appended. Each code block can be LDPC coded individually. Then, rate matching is performed individually on the LDPC coded blocks. Next, code block concatenation can be performed to create codewords for transmission. In box 1408, the contents of the codeword can be scrambled and modulated in box 1410 to generate complex-valued modulated symbol blocks. The symbols are then mapped to one or more layers via inverse fast Fourier transform (IFFT) 1414. In some examples, the PUSCH supports single codewords that can be mapped to up to four layers. In the case of single-layer transmission only, DFT transform precoding 1412 can be optionally applied if enabled.
[0127] Symbols from IFFT 1414 are then provided to multiplexer 1416, which multiplexes the symbols with demodulation reference signal (DMRS) 1424 and uplink control information (UCI) 1418 (if enabled). As shown, the mapping of RRC configuration for DMRS 1424 can be provided by PRACH 1422. The output of the multiplexer is then used in block 1420 for radio resource and mapping to output the msgA payload (1110). For layer-to-antenna port mapping, both non-codebook-based and codebook-based transmissions can be supported in the UL. For each antenna port in the antenna ports used for physical channel transmission, symbols can be mapped to RBs. In some examples, mapping can be performed at the frequency prior to time to enable early decoding at the receiver.
[0128] Figure 15 This is a block diagram 1500 illustrating physical layer processing for multiplexing CSI / CQI reports with uplink control information (UCI) according to some aspects. Figure 15 Examples can be used to form with Figure 13 The CSI / CQI report for the multiplexing of the msgA PUSCH and other MAC-CEs in the msgA payload is shown. In box 1404, channel coding and rate matching are performed on the msgA payload 1504. Similar to... Figure 14In the example, channel coding may include additional transport block CRC to provide error detection, followed by low-density parity-check (LDPC) basemap selection. The msgA payload 1504 can be segmented into code blocks and code block CRC appended. Each code block can be LDPC coded individually. Then, individual rate matching is performed on the LDPC coded blocks. Next, code block concatenation can be performed to create codewords for transmission. In box 1508, the contents of the codeword can be scrambled and modulated in box 1510 to generate complex-valued modulated symbol blocks. The symbols are then mapped to one or more layers via inverse fast Fourier transform (IFFT) 1514. In some examples, PUSCH supports single codewords that can be mapped to up to four layers. In the case of single-layer transmission only, DFT transform precoding 1512 can be optionally applied if enabled.
[0129] The symbols from IFFT 1514 are then provided to multiplexer 1516, which multiplexes the symbols with demodulated reference signal (DMRS) 1524, where, as shown, the RRC configuration mapping for DMRS 1524 can be provided by PRACH 1522. In this example, as described above... Figure 13 The CSI / CQI report 1502 is mapped to uplink control information (UCI) 1518 and multiplexed with other symbols in multiplexer 1516. Then, in block 1520, the output of the multiplexer is used for radio resource and mapping to output the msgA payload (1110). For layer-to-antenna port mapping, both non-codebook-based and codebook-based transmissions can be supported in the UL. For each antenna port used for physical channel transmission, symbols can be mapped to RBs. In some examples, mapping can be performed in the frequency prior to time to enable early decoding at the receiver.
[0130] Those skilled in the art will understand that this disclosure provides flexibility for CSI / CQI reporting. Figure 15 In the example, CSI / CQI reports that the payload of msgA is reused during the construction of msgA, while Figure 14 In the example, the CSI / CQI report is multiplexed with the msgA payload before the message payload is constructed. In a further example, the CSI / CQI report can be configured to occur during a PUSCH retransmission (reTX) and can be scheduled / triggered using fallbackRAR.
[0131] Figure 16This diagram illustrates the signaling 1600 between scheduling entity 1604 and scheduling entity 1602 during the RACH process, when only the RA preamble (msgA) is decoded, according to some aspects, where CSI / CQI reports are multiplexed into the PUSCH retransmission. Similar to... Figure 10 In the example shown, scheduled entity 1604 receives SSB and RACH configuration information in 1606 and responds with a msgA preamble and payload in 1608. In box 1610, scheduling entity 1602 may only detect the msgA preamble (i.e., not the payload) and can send msgB-RNTI 1612 to scheduled entity 1604 via PDCCH, and send fallbackRAR to scheduled entity 1604 via msgB PDSCH in 1614, which may also include RAPID (Random Access Preamble ID) and uplink grant for MsgA PUSCH retransmission. After the scheduled entity decodes the fallbackRAR, in 1616, the scheduled entity provides a multiplexed CSI / CQI report to PUSCH reTX. In some examples, the CSI / CQI report is mapped to a MAC CE, which is multiplexed with other MAC CEs in the PUSCH retransmission. In other examples, CSI / CQI is mapped to UCI, which is multiplexed with the retransmitted (reTX) PUSCH.
[0132] exist Figure 16 In the example, CSI / CQI reporting can be triggered in several ways. For instance, CSI / CQI reporting can be triggered by the msgB PDCCH, for example, using reused and / or reserved bits in the msgB PDCCH payload. Alternatively or additionally, CSI / CQI reporting can be triggered by fallbackRAR, for example, using reserved and / or padding bits in the fallbackRAR payload.
[0133] Figure 17 Block diagram 1700 illustrates a retransmitted PUSCH 1702 that includes a multiplexed CSI / CQI report 1704 during the RACH process, according to some aspects. In this example, the retransmitted PUSCH 1702 includes a CSI / CQI report mapped to a MAC CE and multiplexed with other MAC CEs in the retransmitted msgA payload 1706. Figure 18This is another block diagram 1800 illustrating a retransmitted PUSCH including multiplexed CSI / CQI reports during the RACH process, based on several aspects. In this example, the CSI / CQI report 1804 is mapped to uplink control information (UCI), which can be multiplexed with other MAC-CEs, as shown in the diagram, including the retransmitted (reTX) PUSCH 1802 and the retransmitted msgA payload 1806.
[0134] Figure 19 This diagram illustrates signaling 1900 between scheduled entity 1904 and scheduling entity 1902 during the RACH process, when the RA payload (msgA) is decoded, according to some aspects, where a CSI / CQI report is multiplexed into the HARQ feedback to the RA response (RAR). In this example, scheduled entity 1904 receives the SSB and RACH configuration information at 1906 and responds with the msgA preamble and payload at 1908. In block 1910, scheduling entity 1902 decodes the msgA payload and sends msgB PDCCH 1912 and msgB PDSCH 1914, along with successRAR and uplink grant for scheduling PUSCH, to scheduled entity 1904. Scheduled entity 1904 decodes successRAR to trigger a CSI / CQI report multiplexed with the HARQ feedback to the msgB PDSCH at 1916. In one example, the scheduled entity 1904 can multiplex the CSI-CQI with the HARQ feedback, map the multiplexed CSI-CQI / HARQ feedback to a UCI, and transmit it on the PUCCH. In another example, the scheduled entity 1904 can transmit the CSI / CQI on the PUSCH, which is multiplexed with a UCI carrying the HARQ feedback for msgB.
[0135] exist Figure 19 In the example, CSI / CQI reporting can be triggered in several ways. For instance, CSI / CQI reporting can be triggered by msgB PDCCH using, for example, reused and / or reserved bits in msgB PDCCH. Alternatively or additionally, CSI / CQI reporting can be triggered by successRAR using, for example, reserved and / or padding bits in successRAR.
[0136] Figure 20This is a block diagram illustrating the CSI / CQI multiplexing with HARQ feedback mapped to UCI transmitted on the Physical Uplink Control Channel (PUCCH), based on some aspects. In this example, UCI transmitted on PUCCH 2002 is shown. Here, CSI-CQI report 2004 and HARQ feedback multiplexing to msgB PDSCH 2006 are mapped to UCI and transmitted on PUCCH 2002, as shown. Figure 21 Another block diagram 2100 illustrates CSI / CQI transmitted on the PUSCH and multiplexed with UCI carrying HARQ feedback, based on some aspects. In this example, CSI / CQI report 2106 is mapped to PUSCH 2102, as shown, with UCI multiplexing with HARQ feedback 2104 carrying msgB.
[0137] The CSI / CQI measurements in this disclosure can be configured to measure various reference signals, including but not limited to SSB, CSI-RS, additional resource signals (RS) sent along with RACH configuration information, and RS scheduled by msgB.
[0138] While the examples discussed above describe various configurations for reusing CSI / CQI reports in a two-step RACH operating environment, the same techniques can also be applied to four-step RACH. Figure 22 This is a diagram illustrating the signaling between the scheduled entity 2204 and the scheduling entity 2202 during the RACH process when a CSI / CQI report is multiplexed to a scheduled PUSCH transmission or a Radio Resource Control (RRC) connection establishment completion message, according to some aspects. Figure 22 Examples combined with the above Figure 6 The similarity of the configurations discussed lies in that the RA process is initiated when the scheduled entity 2204 first receives the SSB, RS, and RACH configuration 2206, as described above. Then, the scheduled entity 2204 randomly selects a preamble and, using power ramping, sends the selected preamble to the scheduling entity 2202 in the RACH preamble message 2208 (msg1) via the selected PRACH resource.
[0139] If scheduling entity 2202 successfully detects the preamble, it sends a Random Access Response (RAR) message 2210 (msg2) including PDCCH and PDSCH to scheduled entity 2204. If msg2 (RAR) 2210 is not received within the RAR window, scheduled entity 2204 can retransmit msg1 2208 using power boost. msg 2210 (PDCCH+PDSCH) includes the identifier of the preamble sent by scheduled entity 2204, TA, TC-RNTI or RARNTI of scheduled entity 2204, and the grant of allocated uplink (UL) resources. The PDCCH in msg2 2210 can be scrambled using RA-RNTI. MAC-CE within the PDSCH provides acknowledgment of receipt of msg1 2208 and the UL grant. To receive msg2 2210, the scheduled entity 2204 can monitor DCI 1_0 for the PDCCH scrambled with RA-RNTI corresponding to the RO used by the scheduled entity 2204 to send msg1 2208, and if detected, continue PDSCH decoding. Upon receiving RAR message 2210, the scheduled entity 2204 compares the preamble ID with the preamble sent by the scheduled entity in the RACH preamble message 2208. If the preamble ID matches the preamble sent in the RACH preamble message 2208, the scheduled entity 2204 applies timing advance and begins the contention resolution process.
[0140] In one example, during contention resolution, the scheduled entity 2204 can use the TA in the PDSCH of msg2 2210 and the allocated uplink resources to multiplex the CSI / CQI report in 2218 with an uplink message (msg3) 2212 such as the PUSCH on the Common Control Channel (CCCH). In this example, it can be combined in a manner similar to the above. Figure 16 The described PUSCHreTX multiplexing 1600 performs multiplexing. After successfully decoding the uplink message, the scheduling entity 2202 sends a contention resolution message 2214 (msg4) to the scheduled entity 2204. When the scheduled entity 2204 receives its own identifier in the contention resolution message 2214, it determines that the random access procedure was successful and completes the RRC connection establishment procedure. As mentioned above, msg4 2214 can have a PDCCH control component and a PDSCH payload component.
[0141] In the alternative / additional example, as the contention from msg4 2214 is resolved, in box 2220, the scheduled entity 2204 can reuse the CSI / CQI report (e.g., an acknowledgment "ACK" for msg4) in msg5. This can be similar to the combination above. Figure 19The publicly available technology is used to perform multiplexing. The CSI / CQI report is then multiplexed and sent along with HARQACK in PUCCH message 2216.
[0142] Figure 23 This is a block diagram illustrating an example of a hardware implementation of a scheduled entity 2300 of the processing system 2314, according to some aspects. For example, the scheduling entity 2300 may be as follows: Figure 1 and / or Figure 2 Any one or more of the user equipment (UE) shown.
[0143] The scheduled entity 2300 may be implemented using a processing system 2314 (or “processing apparatus”) including one or more processors 2304. Examples of processors 2304 include microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. In various examples, the scheduled entity 2300 may be configured to perform any one or more of the functions described herein, including but not limited to NR and NR lightweight communications, including the RACH procedure and CSI / CQI multiplexing as described above. That is, the processor 2304 used in the scheduled entity 2300 may be used to implement any one or more of the procedures and programs described herein.
[0144] In this example, processing system 2314 can be implemented using a bus architecture (typically represented by bus 2302). Depending on the specific application and overall design constraints of processing system 2314, bus 2302 may include any number of interconnect buses and bridges. Bus 2302 communicatively couples various circuits together, including one or more processors (typically represented by processor 2304), memory 2305, and computer-readable media (typically represented by computer-readable media 2306). Bus 2302 may also link various other circuits, such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further. Bus interface 2308 provides an interface between bus 2302 and transceiver 2310. Transceiver 2310 provides a communication interface or means for communicating with various other devices via a transmission medium. Depending on the nature of the device, a user interface 2312 (e.g., keyboard, display, speaker, microphone, joystick) may also be provided. Of course, such a user interface 2312 is optional and may be omitted in some examples.
[0145] In some aspects of this disclosure, processor 2304 may include RACH processing circuitry 2320, which is configured to implement, for example, the RACH process described herein, such as Figure 7 , 9 The techniques and methods described in sections -11, 16, 19, and 22. The CSI / CQI multiplexing circuit 2322 can be configured to implement, for example, the CSI / CQI report multiplexing described herein, and the techniques and methods described above. Figure 11-22 The technology described herein. Processor 2304 is responsible for managing bus 2302 and general processing, including executing software stored on computer-readable medium 2306. When executed by processor 2304, the software causes processing system 2314 to perform the various functions described below for any particular device. Computer-readable medium 2306 and memory 2305 may also be used to store data manipulated by processor 2304 when executing the software.
[0146] One or more processors 2304 in the processing system 2314 can execute software. Software should be interpreted broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, application programs, software applications, software packages, routines, subroutines, objects, executable programs, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description languages, or others. The software may reside on a computer-readable medium 2306. The computer-readable medium 2306 may be a non-transitory computer-readable medium. For example, non-transitory computer-readable media include magnetic storage devices (e.g., hard disks, floppy disks, magnetic stripes), optical discs (e.g., compact discs (CDs) or digital versatile discs (DVDs)), smart cards, flash memory devices (e.g., card, stick, or key drives), random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, removable disks, and any other devices. Computer-readable medium 2306 may reside in, be outside of, or be distributed across multiple entities including processing system 2314. Computer-readable medium 2306 may be embodied in a computer program product. For example, a computer program product may include a computer-readable medium in packaging material. Those skilled in the art will recognize how best to implement the functionality described throughout this disclosure, depending on the specific application and the overall design constraints imposed on the system.
[0147] In one or more examples, computer-readable storage medium 2306 may include RACH processing instructions 2306 configured for various functions, including but not limited to RACH processing associated with the functions of RACH processor 2320. Computer-readable storage medium 2306 may also include CSI / CQI multiplexing instructions 2326 configured for various functions, including but not limited to CSI / CQI report multiplexing associated with the functions of CSI / CQI multiplexing circuitry 2322.
[0148] Of course, in the above examples, the circuitry included in processor 2314 is provided merely as an example, and other means for performing the described functions may include, but are not limited to, instructions stored in computer-readable storage medium 2306, or in Figure 1-2 Any other suitable device or device module described in any of the above and 4, and utilizing, for example, the processes and / or algorithms described herein.
[0149] Figure 24 This is a flowchart 2400 illustrating an exemplary process for multiplexing a CSI report with a random access procedure message, according to some aspects. In block 2402, the scheduled entity (e.g., 106) receives a downlink (DL) reference signal (RS) from a scheduling entity (e.g., 108) on a channel between the scheduling entity and the scheduled entity. In block 2404, the scheduled entity uses the received DL RS to obtain channel state information (CSI) of the channel between the scheduling entity and the scheduled entity, and selects an uplink resource associated with the random access procedure in block 2406. In block 2408, the scheduled entity multiplexes a CSI report including the CSI with a random access message associated with the random access procedure to produce multiplexed information, and in block 2410, sends the multiplexed information to the scheduling entity in the random access message on the selected uplink resource.
[0150] Those skilled in the art will understand that this disclosure provides various techniques for multiplexing CSI / CQI reports during the RACH process, and also provides improved communication under various operating states of scheduled entities. For example, for idle or inactive scheduled entities, SSB-based RSRP measurements can be multiplexed with CCCH messages and mapped to msgA PUSCH to allow accurate RSRP measurements on msgB or RSs scheduled by msgB. CSI reports can be triggered by fallbackRAR or successRAR carried by msgB. Alternatively or additionally, CSI reports can be multiplexed with HARQACK on successRAR, or with PUSCH reTX scheduled by fallbackRAR. In another example, for connected scheduled entities, CSI-RS can be signaled to RO or SSB-RO association mode in dedicated RRC signaling or wake-up signal (WUS). Scheduled entities can multiplex CSI reports with C-RNTI in msgA PUSCH based on SSB or CSI-RS measurements. Improved CSI reporting can be performed on msgB or on CSI-RS scheduled by msgB. As mentioned above, CSI reporting can be multiplexed with HARQ ACKs on msgB or with PUSCH reTX scheduled by fallbackRAR.
[0151] Several aspects of wireless communication networks have been described with reference to exemplary embodiments. As will be readily understood by those skilled in the art, the various aspects described herein can be extended to other telecommunications systems, network architectures, and communication standards.
[0152] For example, these aspects can be implemented in other systems defined by 3GPP, such as Long Term Evolution (LTE), Evolved Packet System (EPS), Universal Mobile Telecommunications System (UMTS), and / or Global System for Mobile Communications (GSM). They can also be extended to systems defined by 3GPP2, such as CDMA2000 and / or Evolved Data Optimization (EV-DO). Other examples can be implemented in systems employing IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra Wideband (UWB), Bluetooth, and / or other suitable systems. The actual telecommunications standards, network architecture, and / or communication standards adopted will depend on the specific application and the overall design constraints imposed on the system.
[0153] In this disclosure, the term “exemplary” is used to mean “serving as an example, instance, or illustration.” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as being more preferred or advantageous than other aspects of this disclosure. Similarly, the term “aspect” does not require that all aspects of this disclosure include the features, advantages, or modes of operation discussed. The term “coupled” as used herein refers to direct or indirect coupling between two objects. For example, if object A is in physical contact with object B, and object B is in contact with object C, then objects A and C can still be considered coupled to each other—even if they are not in direct physical contact with each other. For example, a first object can be coupled to a second object, even if the first object never has direct physical contact with the second object. The terms “circuit” and “circuit system” are used broadly and are intended to include, but are not limited to, hardware implementations of electrical devices and conductors (performance in realizing the functions described in this disclosure when connected and configured) and software implementations of information and instructions (performance in realizing the functions described in this disclosure when executed by a processor).
[0154] Figure 1-24 One or more components, steps, features, and / or functions shown may be rearranged and / or combined into a single component, step, feature, or function, or embodied in several components, steps, or functions. Additional elements, components, steps, and / or functions may be added without departing from the novel features disclosed herein. Figure 1 , 2 The apparatuses, devices, and / or components shown in 4, 6-7, 9-11, 16, 19, and 22-23 can be configured to perform one or more methods, features, or steps described herein. The novel algorithms described herein can also be effectively implemented in software and / or embedded in hardware.
[0155] It should be understood that the specific order or hierarchy of steps in the disclosed method is an illustration of an exemplary process. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the method may be rearranged. The appended method claims present the elements of the various steps in an exemplary order and are not intended to limit one to the specific order or hierarchy presented, unless specifically stated therein.
[0156] The foregoing description is provided to enable those skilled in the art to practice the various aspects described herein. Various modifications to these aspects will readily be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are to be consistent with the full scope of the language of the claims, wherein, unless specifically stated otherwise, singular elements are not intended to mean “one and only one,” but rather “one or more.” Unless specifically stated otherwise, the term “some” means one or more. The phrase referring to “at least one” in a series of items means any combination of those items, including a single member. For example, “at least one of a, b, or c” is intended to cover a; b; c; a and b; a and c; b and c; and a, b, and c. All structural and functional equivalents of the elements of the various aspects described in this disclosure that are known to or will become apparent to those skilled in the art herein are expressly incorporated herein by reference and are intended to be included in the claims. Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is expressly stated in the claims. No claim element shall be interpreted in accordance with 35 USC 112(f) unless the element is explicitly stated using the phrase “means for…” or, in the case of a method claim, the element is stated using the phrase “steps for…”.
Claims
1. A method for wireless communication between a scheduled entity and a scheduling entity in a wireless communication network, the method comprising, at the scheduled entity: Receive downlink DL reference signal RS from the scheduling entity on the channel between the scheduling entity and the scheduled entity; The channel state information (CSI) of the channel between the scheduling entity and the scheduled entity is obtained using the received DL RS. Select uplink resources associated with the random access procedure; The CSI report, including the CSI, is multiplexed with the random access message associated with the random access procedure to generate multiplexed information; On the selected uplink resource, the multiplexed information is sent to the scheduling entity in the random access message; The random access message includes a Physical Uplink Shared Channel (PUSCH) for a Type 1 or Type 2 random access procedure, and the multiplexed information is carried in the PUSCH; and The multiplexing of the CSI report with the random access message includes: mapping the CSI report to the Media Access Control (MAC) control element (CE) of the PUSCH payload, and multiplexing the MAC CE with the random access message.
2. The method according to claim 1, wherein, The DL RS includes at least one of a Synchronization Signal Block (SSB) or a CSI-RS, and wherein the DL RS is broadcast to the scheduled entity or dedicated to at least one of the scheduled entities.
3. The method according to claim 1, wherein, Obtaining the CSI includes measuring the received DL RS.
4. The method according to claim 1, wherein, The scheduled entity has an Idle Radio Resource Control (RRC) state, wherein the random access message includes a Common Control Channel (CCCH) message, and wherein multiplexing the CSI report with the random access message includes multiplexing the CSI report with the CCCH message.
5. The method according to claim 1, wherein, The scheduled entity has a connected RRC state, wherein the random access message includes a cell radio network temporary identifier (C-RNTI), and wherein multiplexing the CSI report with the random access message includes multiplexing the CSI report with the C-RNTI.
6. The method according to claim 1, wherein, The selected uplink resources are used for the transmission of preamble and PUSCH for the Type 2 random access procedure.
7. The method according to claim 1, wherein, Multiplexing the CSI report with the random access message includes: mapping the CSI report to uplink control information (UCI) and multiplexing the UCI with the random access message.
8. The method according to claim 7, wherein, Multiplexing the UCI with the random access message includes punching the resource element RE of the PUSCH payload.
9. The method according to claim 7, wherein, Multiplexing the UCI with the random access message includes rate matching of the resource elements (REs) of the PUSCH payload.
10. The method according to claim 1, wherein, The random access message includes one or more of the following: common control channel message, cell radio network temporary identifier, user plane data, or control plane data.
11. The method of claim 1, further comprising receiving a random access channel (RACH) configuration message via at least one of Radio Resource Control (RRC) signaling or System Information Block (SIB), wherein, The selection of uplink resources is performed based on the RACH configuration message.
12. The method according to claim 1, wherein, The uplink resources are used to transmit the Physical Uplink Control Channel (PUCCH) for the CSI report and Hybrid Automatic Repeat Request (HARQ) feedback, and wherein multiplexing the CSI report with the random access message includes multiplexing the CSI report with the HARQ feedback.
13. The method according to claim 1, wherein, The uplink resources are used to transmit the Physical Uplink Shared Channel (PUSCH) for HARQ feedback after decoding the Random Access Response (RAR). The method further includes mapping the HARQ feedback to Uplink Control Information (UCI), multiplexing the UCI with the PUSCH, and wherein the multiplexing of the CSI report with the random access message is accomplished by puncturing the resource element (RE) of the PUSCH or by rate matching.
14. The method of claim 13, further comprising receiving a downlink control channel message for scheduling the RAR, wherein, The downlink control channel message includes a trigger for sending the CSI report in the PUSCH or in the physical uplink control channel PUCCH.
15. The method of claim 1, further comprising comparing the payload size of the random access message with a data size threshold for network configuration of the uplink resources, and in response to the comparison, sending the multiplexing information.
16. A method for wireless communication between a scheduled entity and a scheduling entity in a wireless communication network, the method comprising, at the scheduled entity: Receive downlink DL reference signal RS from the scheduling entity on the channel between the scheduling entity and the scheduled entity; The channel state information (CSI) of the channel between the scheduling entity and the scheduled entity is obtained using the received DL RS. Select uplink resources associated with the random access procedure; The CSI report, including the CSI, is multiplexed with the random access message associated with the random access procedure to generate multiplexed information; On the selected uplink resource, the multiplexed information is sent to the scheduling entity in the random access message; After initiating the random access procedure, a random access response (RAR) is received from the scheduling entity, which schedules the PUSCH. Sending the multiplexing information includes sending the PUSCH in response to the RAR. The random access message includes a Physical Uplink Shared Channel (PUSCH) for a Type 1 or Type 2 random access procedure, and the multiplexed information is carried in the PUSCH; and The multiplexing of the CSI report with the random access message includes: mapping the CSI report to the Media Access Control (MAC) control element (CE) of the PUSCH, and multiplexing the MAC CE with the PUSCH.
17. The method according to claim 16, wherein, The DL RS includes at least one of a Synchronization Signal Block (SSB) or a CSI-RS, and wherein the DL RS is broadcast to the scheduled entity or dedicated to at least one of the scheduled entities.
18. The method according to claim 16, wherein, The RAR includes triggering the sending of the CSI report in the PUSCH.
19. The method of claim 16, further comprising receiving a downlink control channel message from the scheduling entity before transmitting the PUSCH, wherein, The control channel message includes a trigger for sending the CSI report in the PUSCH.
20. The method according to claim 19, wherein, The downlink control channel messages include msg2 Physical Downlink Control Channel (PDCCH) for Type 1 random access procedures or msgB PDCCH for Type 2 random access procedures.
21. A scheduled entity within a wireless communication network, comprising: transceiver; Memory; and A processor communicatively coupled to the transceiver and the memory, wherein the processor and the memory are configured to: Receive downlink DL reference signal RS from the scheduling entity on the channel between the scheduling entity and the scheduled entity; The channel state information (CSI) of the channel between the scheduling entity and the scheduled entity is obtained using the received DL RS. Select uplink resources associated with the random access procedure; The CSI report, including the CSI, is multiplexed with the random access message associated with the random access procedure to generate multiplexed information; On the selected uplink resource, the multiplexed information is sent to the scheduling entity in the random access message; After initiating the random access procedure, a random access response (RAR) is received from the scheduling entity, the RAR scheduling the PUSCH, wherein sending the multiplexed information includes: sending the PUSCH in response to the RAR; The random access message includes a Physical Uplink Shared Channel (PUSCH) for a Type 1 or Type 2 random access procedure, and the multiplexed information is carried in the PUSCH; and Sending the PUSCH in response to the RAR includes: decoding the uplink UL grant in the RAR, wherein the PUSCH includes a retransmitted PUSCH based on the UL grant.
22. The scheduled entity according to claim 21, wherein, The DL RS includes at least one of a Synchronization Signal Block (SSB) or a CSI-RS, and wherein the DL RS is broadcast to the scheduled entity or dedicated to at least one of the scheduled entities.
23. A method for wireless communication between a scheduled entity and a scheduling entity in a wireless communication network, the method comprising, at the scheduled entity: Receive downlink DL reference signal RS from the scheduling entity on the channel between the scheduling entity and the scheduled entity; The channel state information (CSI) of the channel between the scheduling entity and the scheduled entity is obtained using the received DL RS. Select uplink resources associated with the random access procedure; The CSI report, including the CSI, is multiplexed with the random access message associated with the random access procedure to generate multiplexed information; On the selected uplink resource, the multiplexed information is sent to the scheduling entity in the random access message; Measure the received power of the beamforming reference signal from the scheduling entity; The measured received power is compared with a threshold. as well as In response to the comparison, the multiplexed information is sent.
24. A scheduled entity within a wireless communication network, comprising: transceiver; Memory; and A processor communicatively coupled to the transceiver and the memory, wherein the processor and the memory are configured to: Receive downlink DL reference signal RS from the scheduling entity on the channel between the scheduling entity and the scheduled entity; The channel state information (CSI) of the channel between the scheduling entity and the scheduled entity is obtained using the received DL RS. Select uplink resources associated with the random access procedure; The CSI report, including the CSI, is multiplexed with the random access message associated with the random access procedure to generate multiplexed information; On the selected uplink resource, the multiplexed information is sent to the scheduling entity in the random access message; The random access message includes a Physical Uplink Shared Channel (PUSCH) for a Type 1 or Type 2 random access procedure, and the multiplexed information is carried in the PUSCH; and The multiplexing of the CSI report with the random access message includes: mapping the CSI report to the Media Access Control (MAC) control element (CE) of the PUSCH payload, and multiplexing the MAC CE with the random access message.
25. A scheduled entity within a wireless communication network, comprising: transceiver; Memory; and A processor communicatively coupled to the transceiver and the memory, wherein the processor and the memory are configured to: Receive downlink DL reference signal RS from the scheduling entity on the channel between the scheduling entity and the scheduled entity; The channel state information (CSI) of the channel between the scheduling entity and the scheduled entity is obtained using the received DL RS. Select uplink resources associated with the random access procedure; The CSI report, including the CSI, is multiplexed with the random access message associated with the random access procedure to generate multiplexed information; On the selected uplink resource, the multiplexed information is sent to the scheduling entity in the random access message; Measure the received power of the beamforming reference signal from the scheduling entity; The measured received power is compared with a threshold; and In response to the comparison, the multiplexed information is sent.