Transmission of preamble and payload messages in random access procedure

Abstract

Systems and methods for transmission of preamble and payload messages in a random access procedure are presented. A wireless communication device can transmit a random access (RA) preamble and a corresponding uplink channel payload to a wireless communication node in a RA procedure. In response to a failure of the transmitted uplink channel payload to the wireless communication node, the wireless communication device can retransmit the corresponding uplink channel payload to the wireless communication node over an uplink grant.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, including but not limited to systems and methods for transmission of preamble and payload messages in a random access procedure. Background Art

[0002] The 3rd Generation Partnership Project (3GPP), a standards organization, is currently developing a new radio interface called 5G New Radio (5GNR) and the Next Generation Packet Core (NG-CN or NGC). 5G NR will have three main components: the 5G Access Network (5G-AN), the 5G Core (5GC), and the User Equipment (UE). To facilitate the implementation of diverse data services and requirements, the elements of the 5GC (also known as network functions) have been simplified, with some being software-based so that they can be adapted as needed. Summary of the Invention

[0003] The example embodiments disclosed herein are intended to address issues related to one or more problems existing in the prior art, as well as to provide additional features that will become clear when referring to the following detailed description in conjunction with the accompanying drawings. According to various embodiments, example systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are presented as examples and not as limitations, and it will be apparent to those skilled in the art reading this disclosure that various modifications may be made to the disclosed embodiments while still within the scope of this disclosure.

[0004] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A wireless communication device may transmit a random access (RA) preamble and a corresponding uplink channel payload to a wireless communication node during a random access (RA) procedure. In response to a failure of the uplink channel payload transmitted to the wireless communication node, the wireless communication device may retransmit the corresponding uplink channel payload to the wireless communication node via an uplink grant.

[0005] In some embodiments, the wireless communication device may receive a fallback RA response (RAR) including an uplink grant from the wireless communication node. The RA procedure may include a contention-free RA (CFRA) procedure.

[0006] In some embodiments, the wireless communication device may create a medium access control (MAC) protocol data unit (PDU) based on a MsgA buffer. The corresponding uplink channel payload may be based on the MsgA buffer. In some embodiments, the wireless communication device may use the MAC PDU to retransmit the corresponding uplink channel payload to the wireless communication node.

[0007] In some embodiments, the wireless communication device may retransmit the corresponding uplink channel payload only once to the wireless communication node.The uplink grant may come from a fallback RA response (RAR).

[0008] In some embodiments, the wireless communication device may retransmit the corresponding uplink channel payload to the wireless communication node via an uplink grant. The scheduling of the uplink channel payload based on the uplink grant may correspond to a new data indicator (NDI) with an initial NDI value. The uplink grant may come from a fallback RA response (RAR). In some embodiments, the wireless communication device may receive a downlink channel addressed to a cell radio network temporary identifier (C-RNTI) from the wireless communication node. The C-RNTI may include a current NDI value. In response to a failure of the uplink channel payload retransmitted to the wireless communication node, the wireless communication device may retransmit the corresponding uplink channel payload based on whether the current NDI value is different from the initial NDI value (or previous NDI value) of the same HARQ process scheduled.

[0009] In some embodiments, when the current NDI value matches the initial NDI value (or previous NDI value) of the same scheduled HARQ process, the wireless communication device may retransmit the corresponding uplink channel payload buffered in the buffer memory of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, when the current NDI value is different from the initial NDI value (or previous NDI value) of the same scheduled HARQ process, the wireless communication device may initiate a transmission based on the new schedule of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to a protocol.

[0010] In some embodiments, the wireless communication device may maintain or hold a hybrid automatic repeat request (HARQ) buffer memory based on the transmission of the RA preamble code and the corresponding uplink channel payload. The HARQ buffer memory may include a medium access control (MAC) protocol data unit (PDU). In some embodiments, the transmission of the RA preamble code and the corresponding uplink channel payload may be the last random access attempt and may be performed using CFRA resources. In some embodiments, the wireless communication device may retransmit the corresponding uplink channel payload in the MAC PDU to the wireless communication node. In some embodiments, the wireless communication device may retransmit the corresponding uplink channel payload to the wireless communication node using a redundancy version (RV). The RV may be indicated in a fallback RA response (RAR).

[0011] In some embodiments, a wireless communication device may retransmit a corresponding uplink channel payload in a MAC PDU to a wireless communication node corresponding to a new data indicator (NDI) having an initial value. In some embodiments, in response to a failure of the retransmitted uplink channel payload to the wireless communication node, the wireless communication device may retransmit the corresponding uplink channel payload based on whether the value of the NDI has changed from the initial value.

[0012] In some embodiments, in response to a failure of an uplink channel payload retransmitted by the wireless communication node, the wireless communication device may retransmit the corresponding uplink channel payload via an uplink grant addressed to a downlink channel of a cell radio network temporary identifier (C-RNTI). In some embodiments, when the value of NDI has not changed relative to an initial value (or a previous NDI value) of the same scheduled HARQ process, the wireless communication device may retransmit the corresponding uplink channel payload cached in a buffer memory of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, when the value of NDI has changed relative to an initial value (or a previous NDI value) of the same scheduled HARQ process, the wireless communication device may initiate transmission based on a new schedule of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to a protocol.

[0013] In some embodiments, the wireless communication device may determine the NDI value as a previous new data indicator (NDI) value of a transmission of a hybrid automatic repeat request (HARQ) process that occurred prior to the transmission of the same HARQ process RA preamble and corresponding uplink channel payload to the wireless communication node using the same HARQ process. In some embodiments, the wireless communication device may receive a downlink channel addressed to a cell radio network temporary identifier (C-RNTI) from the wireless communication node. The downlink channel may include a current NDI value. In some embodiments, in response to a failure of an uplink channel payload retransmitted to the wireless communication node, the wireless communication device may retransmit the corresponding uplink channel payload based on whether the current NDI value is different from the previous NDI value. In some embodiments, the uplink grant may come from a downlink channel addressed to a cell radio network temporary identifier (C-RNTI).

[0014] In some embodiments, a wireless communication device may transmit an RA preamble and a corresponding uplink channel payload to a wireless communication node in response to a new data indicator (NDI) having an initial value. The corresponding uplink channel payload may be in a MAC PDU. In some embodiments, in response to a failure of the uplink channel payload transmitted to the wireless communication node, the wireless communication device may retransmit the corresponding uplink channel payload to the wireless communication node based on whether the value of the NDI has changed from the initial value.

[0015] In some embodiments, when the value of the NDI does not change from the initial value, the wireless communication device may retransmit the corresponding uplink channel payload buffered in the buffer memory of the hybrid automatic repeat request (HARQ) process. In some embodiments, the wireless communication device may maintain the HARQ buffer memory based on the transmission of the RA preamble code and the corresponding uplink channel payload. The HARQ buffer memory may include a medium access control (MAC) protocol data unit (PDU). The wireless communication device may retransmit the corresponding uplink channel payload in the MAC PDU to the wireless communication node.

[0016] In some embodiments, when the value of NDI changes relative to an initial value, the wireless communication device may initiate a transmission based on a new schedule of a hybrid automatic repeat request (HARQ) process. In some embodiments, NDI may be set according to a protocol.

[0017] In some embodiments, a wireless communication device corresponding to a new data indicator (NDI) having an initial value may transmit an RA preamble and a corresponding uplink channel payload to a wireless communication node. The corresponding uplink channel payload may be in a MAC PDU. In some embodiments, in response to receiving an uplink grant addressed to a C-RNTI and in response to the RA procedure being a contention-free RA (CFRA) procedure, the wireless communication device may retransmit the corresponding uplink channel payload based on whether the value of the NDI has changed from the initial value.

[0018] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A wireless communication node may receive a random access (RA) preamble and a corresponding uplink channel payload from a wireless communication device during a RA procedure. In response to a failure of the uplink channel payload transmitted to the wireless communication node, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device via an uplink grant.

[0019] In some embodiments, the wireless communication node may transmit a fallback RA response (RAR) including an uplink grant to the wireless communication device. The RA procedure may include a contention-free RA (CFRA) procedure. In some embodiments, the wireless communication node may cause the wireless communication device to establish a medium access control (MAC) protocol data unit (PDU) based on the MsgA buffer. The corresponding uplink channel payload may be based on the MsgA buffer. In some embodiments, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device using the MAC PDU. In some embodiments, the wireless communication node may re-receive the corresponding uplink channel payload only once from the wireless communication device. The uplink grant may come from the fallback RA response (RAR).

[0020] In some embodiments, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device via an uplink grant. The scheduling of the uplink channel payload based on the uplink grant may correspond to a new data indicator (NDI) with an initial NDI value. The uplink grant may come from a fallback RA response (RAR). In some embodiments, the wireless communication node may transmit a downlink channel addressed to a cell radio network temporary identifier (C-RNTI) to the wireless communication device. The downlink channel may include a current NDI value. In response to a failure of an uplink channel payload retransmitted to the wireless communication node, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device based on whether the current NDI value is different from the initial NDI value (or previous NDI value) of the same HARQ process scheduled.

[0021] In some embodiments, when the current NDI value matches the initial NDI value (or previous NDI value) of the same scheduled HARQ process, the wireless communication node may re-receive the corresponding uplink channel payload buffered in the buffer memory of the corresponding hybrid automatic repeat request (HARQ) process from the wireless communication device. In some embodiments, when the current NDI value is different from the initial NDI value (or previous NDI value) of the same scheduled HARQ process, the wireless communication node may cause the wireless communication device to initiate a transmission based on the new schedule of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to a protocol.

[0022] In some embodiments, a wireless communication node may cause the wireless communication device to maintain or hold a hybrid automatic repeat request (HARQ) buffer memory based on the transmission of an RA preamble and a corresponding uplink channel payload. The HARQ buffer memory may include a medium access control (MAC) protocol data unit (PDU). In some embodiments, the transmission of the RA preamble and the corresponding uplink channel payload may be the last random access attempt and may be performed using CFRA resources. In some embodiments, the wireless communication node may re-receive the corresponding uplink channel payload in the MAC PDU from the wireless communication device. In some embodiments, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device using a redundancy version (RV). The RV may be indicated in a fallback RA response (RAR).

[0023] In some embodiments, a wireless communication node may re-receive a corresponding uplink channel payload in a MAC PDU from a wireless communication device. The wireless communication node may correspond to a new data indicator (NDI) having an initial value. In some embodiments, in response to a failure of the retransmitted uplink channel payload to the wireless communication node, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device based on whether the value of the NDI has changed from the initial value.

[0024] In some embodiments, in response to a failure of an uplink channel payload retransmitted to the wireless communication node, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device via an uplink grant of a downlink channel addressed to a cell radio network temporary identifier (C-RNTI).

[0025] In some embodiments, when the value of NDI has not changed from the initial value, the wireless communication node may re-receive the corresponding uplink channel payload buffered in the buffer memory of the hybrid automatic repeat request (HARQ) process from the wireless communication device.

[0026] In some embodiments, when the value of NDI does not change from the initial value, the wireless communication node may cause the wireless communication device to initiate re-reception of the corresponding uplink channel payload buffered in the buffer memory of the hybrid automatic repeat request (HARQ) process. In some embodiments, NDI may be set according to a protocol.

[0027] In some embodiments, in response to a failure of an uplink channel payload retransmitted by the wireless communication node, the wireless communication node may re-receive the corresponding uplink channel payload via an uplink grant of a downlink channel addressed to a cell radio network temporary identifier (C-RNTI). In some embodiments, when the value of NDI has not changed relative to an initial value (or a previous NDI value) of the same scheduled HARQ process, the wireless communication node may re-receive the corresponding uplink channel payload cached in a buffer memory of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, when the NDI value has changed relative to an initial value (or a previous NDI value) of the same scheduled HARQ process, the wireless communication node may cause the wireless communication device to initiate a transmission based on a new schedule of the corresponding hybrid automatic repeat request (HARQ) process. In some embodiments, the NDI may be set according to a protocol.

[0028] In some embodiments, a wireless communication node may cause a wireless communication device to determine an NDI value as a new data indicator (NDI) for a transmission using a hybrid automatic repeat request (HARQ) process that occurs prior to the transmission of an RA preamble and a corresponding uplink channel payload to the wireless communication node using the same HARQ process. In some embodiments, the wireless communication node may transmit a downlink channel addressed to a cell radio network temporary identifier (C-RNTI) to the wireless communication device. The C-RNTI may include a current NDI value. In some embodiments, in response to a failure of an uplink channel payload retransmitted to the wireless communication node, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device based on whether the current NDI value is different from the previous NDI value. In some embodiments, an uplink grant may come from a downlink channel addressed to a cell radio network temporary identifier (C-RNTI).

[0029] In some embodiments, a wireless communication node may receive an RA preamble and a corresponding uplink channel payload from a wireless communication device, the corresponding uplink channel payload being in a MAC PDU. The wireless communication node may correspond to a new data indicator (NDI) having an initial value. In some embodiments, in response to a failure of the uplink channel payload transmitted by the wireless communication node, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device based on whether the value of the NDI has changed from the initial value.

[0030] In some embodiments, when the value of NDI has not changed from the initial value, the wireless communication node may re-receive the corresponding uplink channel payload buffered in the buffer memory of the hybrid automatic repeat request (HARQ) process from the wireless communication device.

[0031] In some embodiments, a wireless communication node may cause the wireless communication device to maintain or retain a HARQ buffer based on the transmission of an RA preamble and a corresponding uplink channel payload. The HARQ buffer may include a medium access control (MAC) protocol data unit (PDU). In some embodiments, the transmission of the RA preamble and the corresponding uplink channel payload may be the last random access attempt and may be performed using CFRA resources. In some embodiments, the wireless communication device may retransmit the corresponding uplink channel payload in the MAC PDU to the wireless communication node.

[0032] In some embodiments, when the value of NDI changes relative to an initial value, the wireless communication node may cause the wireless communication device to initiate a transmission based on a new schedule of a hybrid automatic repeat request (HARQ) process. In some embodiments, NDI may be set according to a protocol.

[0033] In some embodiments, a wireless communication node may receive an RA preamble and a corresponding uplink channel payload from a wireless communication device, the corresponding uplink channel payload being in a MAC PDU. The wireless communication node may correspond to a new data indicator (NDI) having an initial value. In some embodiments, in response to receiving an uplink grant addressed to a C-RNTI and in response to the RA procedure being a contention-free RA (CFRA) procedure, the wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device based on whether the value of the NDI has changed from the initial value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Various example embodiments of the present solution are described in detail below with reference to the accompanying drawings or diagrams. The drawings are provided for illustrative purposes only and depict only example embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be construed as limiting the breadth, scope, or applicability of the present solution. It should be noted that for clarity and ease of illustration, the drawings are not necessarily drawn to scale.

[0035] Figure 1 shows an example cellular communication network in which the techniques disclosed herein may be implemented according to embodiments of the present disclosure;

[0036] Figure 2 A block diagram illustrating an example base station and user equipment according to some embodiments of the present disclosure is shown;

[0037] Figure 3A A sequence diagram illustrating an example procedure of a contention-based random access (CBRA) procedure with a 4-step random access (RA) type according to an embodiment of the present disclosure;

[0038] Figure 3B A sequence diagram illustrating an example procedure of a contention-based random access (CBRA) procedure with a 2-step random access (RA) type according to an embodiment of the present disclosure;

[0039] Figure 3C A sequence diagram illustrating an example procedure of a contention-free random access (CFRA) procedure with a 4-step random access (RA) type according to an embodiment of the present disclosure;

[0040] Figure 3D A sequence diagram illustrating an example procedure of a contention-free random access (CFRA) procedure with a 2-step random access (RA) type according to an embodiment of the present disclosure;

[0041] Figure 3E A block diagram illustrating an example allocation or distribution of random access (RA) preambles according to an embodiment of the present disclosure; and

[0042] Figure 4 A flow chart illustrating an example method for transmission of a preamble and a payload message in a random access (RA) procedure according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0043] Various example embodiments of the present solution are described below in conjunction with the accompanying drawings to enable a person of ordinary skill in the art to make and use the present solution. As will be clear to a person of ordinary skill in the art, after reading the contents of this disclosure, various changes or modifications can be made to the examples described herein without departing from the scope of the present solution. Therefore, the present solution is not limited to the example embodiments and applications described and illustrated herein. In addition, the specific order or hierarchy of steps in the methods disclosed herein are merely example methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes can be rearranged while remaining within the scope of the present solution. Therefore, a person of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or actions in an example order, and the present solution is not limited to the specific order or hierarchy presented, unless otherwise expressly stated.

[0044] The following acronyms are used throughout this disclosure:

[0045]

[0046]

[0047]

[0048]

[0049] I. Mobile communications technology and environment

[0050] Figure 1 An example wireless communication network and / or system 100 is shown in which the techniques disclosed herein may be implemented in accordance with embodiments of the present disclosure. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as "network 100." Such an example network 100 includes a base station 102 (hereinafter "BS 102"; also referred to as a wireless communication node) and a user equipment device 104 (hereinafter "UE 104"; also referred to as a wireless communication device) that may communicate with each other via a communication link 110 (e.g., a wireless communication channel), and a cluster of cells 126, 130, 132, 134, 136, 138, and 140 covering a geographic area 101. Figure 1 1 , BS 102 and UE 104 are contained within the respective geographic boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating on its allocated bandwidth to provide adequate radio coverage to its intended users.

[0051] For example, BS 102 can operate on the allocated channel transmission bandwidth to provide sufficient coverage to UE 104. BS 102 and UE 104 can communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 can be further divided into subframes 120 / 127, which can include data symbols 122 / 128. In the present disclosure, BS 102 and UE 104 are described herein as non-limiting examples of "communication nodes," which can generally practice the methods disclosed herein. According to various embodiments of the present solution, such communication nodes can be capable of wireless and / or wired communication.

[0052] Figure 2 A block diagram of an example wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM / OFDMA signals) according to some embodiments of the present solution is shown. The system 200 may include components and elements configured to support known or conventional operating features that need not be described in detail herein. In one illustrative embodiment, the system 200 may be used in applications such as Figure 1 Data symbols are communicated (eg, transmitted and received) in a wireless communication environment such as the wireless communication environment 100 of FIG. 1 , as described above.

[0053] System 200 generally includes a base station 202 (hereinafter referred to as "BS 202") and a user equipment device 204 (hereinafter referred to as "UE 204"). BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled to and interconnected with each other via a data communication bus 220 as needed. UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled to and interconnected with each other via a data communication bus 240 as needed. BS 202 communicates with UE 204 via a communication channel 250, which can be any wireless channel or other medium suitable for data transmission as described herein.

[0054] As will be understood by those skilled in the art, the system 200 may also include Figure 2 Any number of additional modules beyond those shown. Those skilled in the art will understand that the various illustrative blocks, modules, circuits, and processing logic described in connection with the embodiments disclosed herein may be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. In order to clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, the various illustrative components, blocks, modules, circuits, and steps are generally described in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software may depend on the specific application and the design constraints imposed on the overall system. A person familiar with the concepts described herein may implement such functionality in an appropriate manner for each specific application, but such implementation decisions should not be construed as limiting the scope of the present disclosure.

[0055] According to some embodiments, the UE transceiver 230 may be referred to herein as an "uplink" transceiver 230, and includes a radio frequency (RF) transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in a time-duplexed manner. Similarly, according to some embodiments, the BS transceiver 210 may be referred to herein as a "downlink" transceiver 210, and includes an RF transmitter and an RF receiver, each of which includes circuitry coupled to an antenna 212. A downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in a time-duplexed manner. The operations of the two transceiver modules 210 and 230 may be coordinated in time such that the uplink receiver circuitry is coupled to the uplink antenna 232 for transmission and reception over the wireless transmission link 250 when the downlink transmitter is coupled to the downlink antenna 212. Instead, the operations of the two transceivers 210 and 230 can be coordinated in time such that the downlink receiver is coupled to the downlink antenna 212 for transmission reception over the wireless transmission link 250 while the uplink transmitter is coupled to the uplink antenna 232. In some embodiments, there is tight time synchronization with minimal guard times between changes in duplex direction.

[0056] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250 and to cooperate with appropriately configured RF antenna arrangements 212 / 232 capable of supporting specific wireless communication protocols and modulation schemes. In some illustrative embodiments, the UE transceiver 210 and the base station transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it should be understood that the present disclosure is not necessarily limited to application to specific standards and related protocols. Instead, the UE transceiver 230 and the base station transceiver 210 can be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0057] According to various embodiments, for example, BS 202 can be an evolved Node B (eNB), a serving eNB, a target eNB, a femto station, or a pico station. In some embodiments, UE 204 can be implemented in various types of user equipment, such as mobile phones, smart phones, personal digital assistants (PDAs), tablet computers, laptop computers, wearable computing devices, etc. Processor modules 214 and 236 can be implemented or implemented with a general-purpose processor designed to perform the functions described herein, a content addressable memory, a digital signal processor, an application-specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. In this manner, the processor can be implemented as a microprocessor, a controller, a microcontroller, a state machine, etc. The processor can also be implemented as a combination of computing devices, for example, a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a digital signal processor core, or any other such configuration.

[0058] Furthermore, the steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly in hardware, firmware, or software modules executed by processor modules 214 and 236, respectively, or any practical combination thereof. Memory modules 216 and 234 may be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, memory modules 216 and 234 may be coupled to processor modules 210 and 230, respectively, such that processor modules 210 and 230 may read information from and write information to memory modules 216 and 234, respectively. Memory modules 216 and 234 may also be integrated into their respective processor modules 210 and 230. In some embodiments, each of memory modules 216 and 234 may include a cache memory for storing temporary variables or other intermediate information during the execution of instructions to be executed by processor modules 210 and 230, respectively. Memory modules 216 and 234 may each also include non-volatile memory for storing instructions to be executed by processor modules 210 and 230, respectively.

[0059] The network communication module 218 generally represents the hardware, software, firmware, processing logic and / or other components of the base station 202 that enable bidirectional communication between the base station transceiver 210 and other network components and communication nodes configured to communicate with the base station 202. For example, the network communication module 218 can be configured to support Internet or WiMAX services. In a typical deployment, but not by way of limitation, the network communication module 218 provides an 802.3 Ethernet interface so that the base station transceiver 210 can communicate with a conventional Ethernet-based computer network. In this manner, the network communication module 218 can include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). As used herein with respect to a specified operation or function, the terms "configured for," "configured to," and variations thereof refer to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted, and / or arranged to perform the specified operation or function.

[0060] The Open Systems Interconnection (OSI) model (referred to herein as the "OSI model") is a conceptual and logical arrangement that defines network communications used by systems (e.g., wireless communication devices, wireless communication nodes) that are open to interconnection and communication with other systems. The model is divided into seven subcomponents or layers, each of which represents a conceptual set of services provided to the layers above and below it. The OSI model also defines logical networks and effectively describes computer packet transmissions by using different layer protocols. The OSI model may also be referred to as a seven-layer OSI model or a seven-layer model. In some embodiments, the first layer may be a physical layer. In some embodiments, the second layer may be a medium access control (MAC) layer. In some embodiments, the third layer may be a radio link control (RLC) layer. In some embodiments, the fourth layer may be a packet data convergence protocol (PDCP) layer. In some embodiments, the fifth layer may be a radio resource control (RRC) layer. In some embodiments, the sixth layer may be a non-access stratum (NAS) layer or an Internet Protocol (IP) layer, and the seventh layer is another layer.

[0061] 2. Used in System and method for transmitting a preamble and payload message in a random access procedure

[0062] The present system and method address how to configure and select RA preamble and physical uplink shared channel (PUSCH) payload message (sometimes referred to herein as MsgA) transmission resources for UEs (e.g., UE 104) in different states. The states can be separate for UEs in idle / inactive mode and UEs in connected mode. In addition, the present system and method address how to handle the situation where a network (NW) side device (e.g., BS 102) has successfully decoded the preamble but failed to receive or decode the corresponding PUSCH payload in the case of a 2-step RA type random access procedure.

[0063] Under random access (RA) procedures, 4-step RA type and 2-step RA type can be supported. In some cases, 4-step RA type RACH can be referred to as Type 1, and 2-step RA type RACH can be referred to as Type 2 RACH procedure, and vice versa. For each type of RACH procedure, both contention-based RACH and contention-free RACH can be applied, which can result in four RACH procedures in total: contention-based RA (CBRA) with 4-step RA type (e.g., sequence 300A as shown in Figure 3A Figure 3C Figure 3B Figure 3D

[0064] The general procedure of 2-step RA type random access procedure can be summarized as follows. First, the UE can transmit MsgA to the NW side. MsgA can include the transmission of RA preamble and PUSCH payload. The UE can receive the RA response sent by the NW in response to receiving MsgA.

[0065] A. Selection based on predefined rules

[0066] For 2-step RA type RA procedure, the UE can receive multiple sets of RACH resource configurations. The UE can select 2-step RACH resources based on predefined rules. For each set of 2-step RACH resources, at least one of the following can be included:

[0067] • Preamble group configuration of 2-step RACH. For example, each set of 2-step RACH resources can include two preamble groups (e.g., preamble group A and preamble group B).

[0068] • 2-step PUSCH resources for MsgA transmission. For example, 2-step PUSCH resources can contain parameters specified in the protocol. For example, time domain resources, frequency domain resources, code domain resources, and other parameters specified in the protocol (e.g., 3GPP specification).

[0069] • Multiple sets of 2-step RACH resources can also include a combination of preamble resources (e.g., preamble configuration as specified above) and PUSCH resources (e.g., preamble configuration as specified above). For example: multiple preamble group configurations can be provided, and each preamble group can be linked to one PUSCH resource configuration; and

[0070] ​​​​• The multiple set of RACH resource configuration for 2-step RA type RA procedure can be configured from NW to UE through broadcast system information, through dedicated RRC signaling.

[0071] The configuration of 2-step CFRA resource can contain at least one of the following two parts:

[0072] First part: Contention-free preamble resource configuration for 2-step CFRA.

[0073] In some embodiments, the preambles for 2-step CFRA can be reserved from the preamble resource pool for 2-step CBRA (i.e., sharing the RO configuration of 2-step CBRA), or from a separate preamble resource pool (i.e., having separate RO configuration of 2-step CBRA). In order to be able to configure a separate preamble resource pool, a different information element (IE) than the one used to configure 2-step CBRA resource (e.g., RACH-ConfigGenericTwoStepRA-r16) can be allowed. In some embodiments, if RACH-ConfigGenericTwoStepRA-r16 is not configured for 2-step CFRA, the configuration of 2-step CBRA will be reused.

[0074] In some embodiments, the configuration method of contention-free preamble for each SSB / CSI-RS specified in the protocol can be reused for 2-step CFRA:

[0075] • For SSB-based 2-step CFRA:

[0076] ■Configured with RO mask index, which is common for all SSBs

[0077] ■Configured with one preamble index for each SSB.

[0078] • For CSI-RS-based 2-step CFRA:

[0079] ■Configured with rsrp-ThresholdCSI-RS, which is common for all CSI-RSs

[0080] ■Configured with preamble index and RO list for each CSI-RS.

[0081] Second part: Contention-free PUSCH resource configuration for 2-step CFRA.

[0082] In some embodiments, the PUSCH resource for 2-step CFRA can be configured in dedicated signaling. In some embodiments, the same IE for MsgA PUSCH resource configuration of 2-step CBRA can be reused for MsgA PUSCH resource configuration of 2-step CFRA, which includes at least one of the following:

[0083] • msgA-PUSCH-Resource-r16

[0084] • msgA-TransformPrecoder-r16

[0085] • msgA-DataScramblingIndex-r16

[0086] • msgA-DeltaPreamble-r16

[0087] For 2-step CFRA, once configured with a PUSCH resource pool, various techniques can be used to determine the PUSCH resource units reserved for each preamble per SSB / CSI-RS.

[0088] In some embodiments, the mapping rule defined for 4-step CBRA (e.g., as specified in the protocol) can be reused to determine the mapping between each preamble and PUSCH resource units. The mapping rule between preamble and PUSCH resource units defined in Technical Specification 38.213 for 4-step CBRA can be reused. With the mapping rule, each preamble reserved for CFRA can be mapped to a PUSCH resource unit. To enable this alternative, the number of preambles reserved for 2-step CFRA can be provided, and all preambles reserved for 2-step CFRA can be considered in the mapping between preamble and PUSCH resource units, even if a preamble is not reserved for the relevant UE. To indicate the preambles reserved for 2-step CFRA, the following parameters can be used:

[0089] • The parameter can indicate the starting index of MsgA preambles, e.g., msgA-PreambleStartIndex: If N SSBs are associated with a RACH occasion, where N >= 1, for the nth SSB (i = 0,..., N-1), the preambles starting from preamble index are reserved for contention-free 2-step random access, where is provided by totalNumberOfRA-Preambles or msgA-TotalNumberOfRA-Preambles-r16; for N < 1, the preambles starting from preamble index msgA-PreambleStartIndex are reserved for 2-step CFRA.

[0090] • msgA-TotalNumberOfCFRA-Preambles can indicate the total number of preambles for contention-free 2-step random access associated with each SSB in one RO.

[0091] As Figure 3E shown, an example 300E of an abstract illustration of preambles allocated in different SSB / CSI resources is shown. The UE can deduct the allocation of preambles based on the received resource configuration. msgA-PreambleStartIndex can be set to 16 and msgA-TotalNumberOfCFRA-Preambles can be set to 4. With these two parameters, preambles 16-19 and preambles 41-44 can be considered reserved for 2-step CFRA, and these reserved preambles can be mapped to the PUSCH resource units provided by MsgA-PUSCH-Resource-r16 in the signaling of the CFRA resource configuration. Through the mapping between preambles and PUSCH resource units, once a preamble can be reserved for one SSB or CSI-RS, the PUSCH resource units mapped to the preamble can also be reserved.

[0092] In some embodiments, the PUSCH resource unit index for each SSB / CSI-RS can be explicitly configured. The PUSCH resource unit index can be explicitly allocated for each SSB / CSI-RS. For the mapping between PUSCH resource units and preambles, the PUSCH resource unit index can be ordered based on the same order (e.g., as defined in Technical Specification 38.213) (e.g., first, in ascending order of frequency resource index; second, in ascending order of DMRS index within the PUSCH occasion; third, in ascending order of time resource index; fourth, in ascending order of index of PUSCH slot). To enable this alternative, a new IE msgA-PRUIndex can be introduced, and some description will be introduced in 38.213 to specify the meaning of msgA-PRUIndex.

[0093] An example of ASN.1 for the CFRA resource configuration of 2-step RA is given below. The information element (IE) RACH-ConfigDedicated can be used to specify dedicated random access parameters.

[0094]

[0095]

[0096]

[0097] In some embodiments, a pre-defined rule can define or specify that the UE is to select a 2-step RACH resource based on a trigger of the RA procedure in case multiple 2-step RACH resource sets are configured. The RA trigger can comprise at least one of:

[0098] • Initial access from RRC_IDLE;

[0099] • RRC connection re-establishment procedure;

[0100] • DL or UL data arrives while in RRC_CONNECTED when the UL synchronization status is “non-synchronized”;

[0101] • DL or UL data arrives while in RRC_CONNECTED when there is no PUCCH resource for SR

[0102] UL data arrives when available;

[0103] • SR failure;

[0104] • RRC initiation request at synchronization reconfiguration (e.g. handover);

[0105] • Transition from RRC_INACTIVE;

[0106] • To establish time alignment for secondary TAG;

[0107] • Request other SI (e.g. as specified in clause 7.3); and

[0108] • Beam failure recovery.

[0109] The individual triggers or different combinations of RA triggers can be linked to different configured sets of 2-step RA resources, and the UE selects the corresponding set of 2-step RA resources based on the RA trigger. For example, for RA procedure triggered by RRC setup, RRC re-establishment, RRC resume, the UE will select 2-step RACH resource set 1. For RA procedure triggered for any other reason, the UE will select 2-step RACH resource set 2.

[0110] In some embodiments, a pre-defined rule can define or specify that in case multiple sets of 2-step RACH resources are configured, the UE will select the set of 2-step RACH resources based on the content of the MsgA payload. For example:

[0111] • If a CCCH message is to be included in the MsgA payload, 2-step RACH resource set 1 can be used. Otherwise, 2-step RACH resource set 2 will be used.

[0112] • If a C-RNTI is to be included in the MsgA payload, 2-step RACH resource set 1 can be used; otherwise, 2-step RACH resource set 2 will be used.

[0113] In some embodiments, a predefined rule may define or specify that, when multiple 2-step RACH resource sets are configured, the UE will select a 2-step RACH resource set based on whether a valid C-RNTI (cell radio network temporary identifier) ​​is stored for the cell. If a valid C-RNTI is stored on the UE side, the UE uses 2-step RACH resource set 1. Otherwise, the UE uses 2-step RACH resource set 2.

[0114] In some embodiments, the predefined rules may define or specify that the UE selects a 2-step RACH resource based on the presence of a 2-step RACH resource for CONNECTED or a dedicated contention-based 2-step RACH resource. For example, if a 2-step CBRA resource is configured in BWP-UplinkDedicated for the current BWP, the dedicated 2-step CBRA resource may be used instead of the resource configured in the common resource.

[0115] Furthermore, different combinations of the above alternatives can be used, or used together with the selection rules specified in the protocol.

[0116] B. Retransmission of PUSCH payload

[0117] If the NW successfully decodes the preamble but fails to receive or decode the corresponding PUSCH payload, the UE may retransmit the MsgA PUSCH payload and may take one of the following actions.

[0118] I. Transmit or retransmit MsgA PUSCH payload via UL grant received in fallback RAR

[0119] In some embodiments, if a fallback RAR is received in response to an MsgA transmission on CFRA resources, the UE may perform transmission or retransmission of the MsgA PUSCH payload with the UL grant received in the fallback random access response (RAR). In this case, if the received MsgB contains a fallback RAR with the same preamble index as that transmitted in the MsgA, the UE may process the received timing advance command. The UE may ignore the received TC-RNTI (temporary C-RNTI) (because it already has the C-RNTI) and may identify the RA procedure as successfully completed and stop the MsgB response window. The UE may retransmit the MsgA PUSCH payload according to the following alternative scheme.

[0120] a. Generate a new MAC PDU based on the MsgA buffer memory

[0121] In some embodiments, for an UL grant in a fallback RAR, the UE may generate a new MAC PDU based on the MsgA buffer (e.g., in the physical layer). For example, if the RA is considered complete after reception of the fallback RAR and the CFRA resources are used to transmit MsgA, the MsgA buffer may not be flushed immediately. The UE may first generate a new MAC PDU based on the MsgA buffer. In some embodiments, the newly generated MAC PDU may be placed in HARQ process 0 for transmission and transmitted based on the UL grant resources received in the fallback RAR, where the fallback RAR is in response to the MsgA transmission on the CFRA resources. After transmitting the MAC PDU in HARQ process 0, the UE may retain the HARQ buffer for HARQ process 0. In some embodiments, the newly generated MAC PDU may be placed in HARQ process 0. In some embodiments, the UE may retransmit the MsgA PUSCH payload once using the UL grant resources received in the fallback RAR.

[0122] In some embodiments, considering that the retransmission of the PUSCH payload using the UL grant indicated in the fallback RAR may fail again as described above, since the RA has already been completed in this case, the UE may retransmit the MsgA payload buffered in HARQ process 0 based on the scheduling on the PDCCH addressed to the C-RNTI. In this case, an initial New Data Indicator (NDI) value (0 or 1) may be used for the MsgA PUSCH payload transmission scheduled by the UL grant in the fallback RAR, and the UE decides whether this is a new scheduling for HARQ process 0 (e.g., scheduling new data transmission) or whether to retransmit the MsgA payload stored in the HARQ buffer memory of HARQ process 0 based on whether the NDI is toggled.

[0123] The above-mentioned initial NDI value can be predefined in the protocol or broadcast in the system information, or signaled by dedicated signaling or indicated in the fallback RAR (for example, using a bit reserved for TC-RNTI). In some embodiments, if a subsequent scheduling of HARQ process 0 is received on a PDCCH addressed to the C-RNTI after retransmitting the MsgA PUSCH payload using the UL grant received in the fallback RAR, the UE can compare the NDI value received in the PDCCH with the NDI value set for the previous transmission of the same HARQ process before the MsgA transmission. If the NDI is flipped (for example, different from the previous NDI value), the UE can perform a new transmission of HARQ process 0 (for example, new data transmission in HARQ process 0) according to the scheduling configuration received in the PDCCH. Otherwise, if the NDI is not flipped (for example, the same as the previous NDI value), the UE can perform a retransmission of HARQ process 0 according to the scheduling configuration received in the PDCCH.

[0124] For example, the NDI value can be set to "0" to schedule HARQ process 0, and then the UE can use the CFRA resource to initiate a 2-step RA type random access procedure (for example, Figure 3D As shown). If the UE receives a fallback RAR sent from the network to schedule the retransmission of the MsgA PUSCH payload, after transmitting the MsgA, the UE may transmit the MsgA PUSCH payload in HARQ process 0 according to the UL grant indicated in the fallback RAR. Since the transmission scheduled by the UL grant in the fallback RAR does not reset the NDI value, the NDI of HARQ 0 in this case is still "0". Thereafter, if the NDI of the subsequent scheduling of HARQ process 0 on the PDCCH addressed to the C-RNTI is "0", the UE may compare the NDI of the subsequent scheduling with the NDI value of the HARQ process 0 before the MsgA transmission (i.e., 0 in this example), and the NDI is not flipped. If the received NDI is "1", the UE may perform a retransmission of HARQ process 0, which indicates that the NDI is flipped, and the UE will then consider this to be a scheduling for a new transmission.

[0125] b. Reserve HARQ buffer memory to retransmit MsgA payload using UL grant from fallback RAR

[0126] In some embodiments, a HARQ buffer memory may be retained or maintained, and the UL grant from the fallback RAR may be used to process HARQ retransmissions for HARQ process 0. In some embodiments, after RA is completed and the last RA attempt is made on a 2-step CFRA resource as described above, the UE may retain the HARQ buffer memory of the HARQ process (e.g., HARQ process 0) used to transmit the MAC PDU in the MsgA buffer memory (or the Msg3 buffer memory). The UE may use the UL grant received in the fallback RAR to retransmit the MAC PDU buffered in HARQ process 0. In some embodiments, after retransmitting HARQ process 0 using the UL grant indicated in the fallback RAR as described above, the UE may retain or maintain the HARQ buffer memory for the corresponding HARQ process (e.g., HARQ process 0).

[0127] In some embodiments, if an UL grant is received in a fallback RAR, and the previous MsgA transmission of the same HARQ process can be transmitted using 2-step CFRA resources, the UE may assume that the NDI of the HARQ process has not been flipped. The UE may then perform a HARQ retransmission of HARQ process 0.

[0128] In addition, as described above, the RV version for MsgA payload retransmission can be fixed to RV0, or predefined in the protocol (for example, the UE uses a predefined RV mode for MsgA payload retransmission scheduled by UL grant in the fallback RAR, and requires a PDCCH addressed to the C-RNTI to schedule subsequent retransmissions, ignoring the RV indicated in the PDCCH) or the RV indicated in the fallback RAR (for example, indicated using the bit reserved for TC-RNTI).

[0129] In some embodiments, if a subsequent retransmission of the MsgA payload is required after a HARQ retransmission of HARQ process 0 using an UL grant in a fallback RAR in response to an MsgA transmission of the last RA attempt on CFRA resources, the UE may be scheduled using a PDCCH addressed to the C-RNTI. In this case, an initial NDI value (0 or 1) may be used as the NDI value for the MsgA transmission (or MsgA payload retransmission scheduled by the fallback RAR UL grant) for NDI comparison. The initial NDI value may be predefined in the protocol or broadcast in system information, or signaled via dedicated signaling or indicated in the fallback RAR (e.g., using a bit reserved for TC-RNTI). For example, if a fallback RAR for MsgA payload retransmission is received, and the UE assumes that the NDI of the previous MsgA transmission on the CFRA resources was "0," the NDI of the UL grant received in the fallback RAR for the retransmission of the MsgA payload may be "1." If a subsequent UL grant is received on the PDCCH for the C-RNTI of the same HARQ process and the NDI is "1" (e.g., the NDI is not toggled), the UE may perform a retransmission using the configuration indicated in the received PDCCH. Otherwise, if the NDI value is "0" (e.g., the NDI is toggled), the UE may perform a new HARQ transmission as specified in the protocol.

[0130] In some embodiments, if subsequent retransmissions of the MsgA payload are to be used after HARQ retransmission of HARQ process 0 using an UL grant in a fallback RAR received in response to an MsgA transmission of a last RA attempt on CFRA resources, as described above, the UE may be scheduled using a PDCCH addressed to the C-RNTI. For example, as described above, after retransmitting HARQ process 0 using the UL grant indicated in the fallback RAR, the UE may retain or maintain a HARQ buffer memory for HARQ process 0. And the UE may receive a PDCCH addressed to the C-RNTI for scheduling HARQ process 0. The UE may compare the NDI value received in the first scheduling on the PDCCH addressed to the C-RNTI after the MsgA transmission on the 2-step CFRA resources with the NDI value set for the previous transmission of the same HARQ process before the MsgA transmission. In other words, the NDI set for HARQ process 0 before the MsgA transmission on the CFRA resources can be used for NDI comparison for subsequent scheduling on the PDCCH addressed to the C-RNTI after the MsgA transmission on the CFRA resources or the subsequent MsgA payload transmission on the UL grant indicated in the fallback RAR as needed. If the NDI is flipped (i.e., different from the previous NDI value), the UE can perform a new transmission of HARQ process 0 according to the scheduling configuration received in the PDCCH (e.g., the UE flushes the HARQ process 0 buffer memory and transmits new data in HARQ process 0), otherwise if the NDI is not flipped (i.e., the same as the previous NDI value), the UE can perform a retransmission of HARQ process 0 according to the scheduling configuration received in the PDCCH.

[0131] For example, HARQ process 0 can be scheduled with the NDI value set to "0", after which the UE initiates a 2-step RA type random access procedure using CFRA resources. After transmitting MsgA, if the UE receives a fallback RAR sent from the network to schedule the retransmission of the MsgA PUSCH payload, the UE can transmit the MsgA PUSCH payload in HARQ process 0 according to the UL grant indicated in the fallback RAR. Thereafter, if the NDI of a subsequent scheduling of HARQ process 0 on the PDCCH addressed to the C-RNTI is "0", the UE can compare the NDI value of the subsequent scheduling with the NDI value of HARQ process 0 before the MsgA transmission (0 in this example), and if the NDI has not toggled, the UE will perform a retransmission of HARQ process 0. Otherwise, if the received NDI is "1", which indicates that the NDI has toggled, the UE will consider this to be a scheduling for a new transmission.

[0132] In some embodiments, the NDI indication and RV may be included in the fallback RAR for the 2-step CFRA case (using the bits reserved for TC-RNTI). Based on the indicated NDI, the UE may determine to retransmit the MAC PDU in HARQ process 0 using the UL grant in the fallback RAR or to generate a new MAC PDU for the UL grant in the fallback RAR.

[0133] c. Consider using the UL grant in the fallback RAR for new transmission

[0134] In some embodiments, the UE may treat the UL grant in the fallback RAR as a UL grant for a new transmission of the MsgA buffer (or Msg3 buffer). For example, RV 0 and HARQ process 0 may be used to transmit the MsgA payload (e.g., as defined in the protocol). In addition, if a subsequent retransmission is to occur, the retransmission may be scheduled by a PDCCH addressed to the C-RNTI. In this case, an initial value (0 or 1) may be used for the NDI of the new transmission of the MsgA buffer (Msg3 buffer) scheduled by the UL grant in the fallback RAR for NDI comparison. The NDI value may be predefined in the protocol or broadcast in system information, or signaled by dedicated signaling or indicated in the fallback RAR (e.g., using bits reserved for TC-RNTI).

[0135] In some embodiments, after retransmitting HARQ process 0 using the UL grant indicated in the fallback RAR as described above, the UE may retain or maintain a HARQ buffer memory for the corresponding HARQ process (e.g., HARQ process 0). In addition, if a subsequent scheduling is received on a PDCCH addressed to the C-RNTI for a HARQ process (e.g., HARQ process 0) for MsgA transmission after retransmitting the MsgA PUSCH payload using the UL grant received in the fallback RAR in response to the MsgA transmission of the last RA attempt on the CFRA resource, the UE may compare the NDI value received in the PDCCH with the NDI value set for the previous transmission of the same HARQ process before the MsgA transmission. If the NDI is flipped (i.e., different from the previous NDI value), the UE may perform a new transmission for HARQ process 0 (e.g., a new data transmission in HARQ process 0) according to the scheduling configuration received in the PDCCH. Otherwise, if the NDI has not rolled over (ie, is the same as the previous NDI value), the UE may perform retransmission of HARQ process 0 according to the scheduling configuration received in the PDCCH.

[0136] For example, HARQ process 0 may be scheduled with the NDI value set to "0," after which the UE initiates a 2-step RA type random access procedure using CFRA resources. After transmitting MsgA, if the UE receives a fallback RAR sent from the network to schedule the retransmission of the MsgA PUSCH payload, the UE may transmit the MsgA PUSCH payload in HARQ process 0 according to the UL grant indicated in the fallback RAR. Thereafter, if the NDI of a subsequent scheduling of HARQ process 0 performed on the PDCCH addressed to the C-RNTI is "0," the UE may compare the NDI of the subsequent scheduling with the NDI value of HARQ process 0 before the MsgA transmission (0 in this example), and the NDI is not flipped. Otherwise, if the received NDI is "1," the UE may perform a retransmission of HARQ process 0, which indicates that the NDI is flipped, and the UE will consider this to be a scheduling for a new transmission.

[0137] In some embodiments, after receiving a fallback RAR in response to a MsgA transmitted on CFRA resources, the UE may continue the RA procedure and fall back to 4-step CBRA. This may be the same behavior as a fallback RAR received after transmitting a MsgA via 2-step CBRA resources.

[0138] II. Transmit or retransmit MsgAPUSCH payload via UL grant received on PDCCH of C-RNTI

[0139] a. Transmission or retransmission of MsgA payload considering an initial NDI value

[0140] In some embodiments, the UE may perform transmission or retransmission of a MsgA PUSCH payload based on an UL grant received on a PDCCH for the C-RNTI. If the previous uplink grant delivered to the HARQ entity for the same HARQ process was an uplink grant determined for contention-free transmission of MsgA (e.g., as specified in the protocol), a value of 0 (or a value of 1) may be used as the NDI value of the previous MsgA transmission for NDI comparison. The NDI value may be predefined in the protocol or broadcast in system information, or signaled via dedicated signaling. In some embodiments, if RA has been completed and the last RA attempt was made on CFRA resources, the HARQ buffer memory used to transmit the MAC PDU in the MSGA buffer memory (or Msg3 buffer memory) may be reserved to allow the UE to perform HARQ retransmissions.

[0141] In this case, the UE can compare the NDI value received in the PDCCH addressed to the C-RNTI with the initial NDI value assigned for the previous MsgA transmission to determine whether the UL grant is for a new transmission or a retransmission. If the NDI received in the PDCCH scrambled by the C-RNTI is not flipped (e.g., has not changed) compared to the initial value of the previous uplink grant, the UE can identify that the C-RNTI scrambled by the PDCCH is scheduled for retransmission, and the UE can perform retransmission of the PUSCH payload based on the scheduling on the PDCCH addressed to the C-RNTI. Otherwise, if the NDI value received in the PDCCH is flipped (e.g., changed), the UE will perform a new transmission of HARQ process 0 according to the scheduling configuration indicated in the PDCCH (e.g., transmission of new data in HARQ process 0).

[0142] In some embodiments, upon receiving an UL grant indicated in a PDCCH addressed to a C-RNTI, and the previous transmission of the same HARQ process may be an MsgA transmission over CFRA resources, an initial NDI value (0 or 1) may be considered for the previous MsgA transmission. This NDI value may be predefined in the protocol or broadcast in system information, or signaled via dedicated signaling. The UE may determine whether the received UL grant is scheduled for a new transmission or a retransmission by comparing the NDI value received in the PDCCH with the NDI value considered for the previous transmission. If the NDI received in the PDCCH scrambled by the C-RNTI is not flipped (e.g., unchanged) compared to the initial value of the previous uplink grant, the UE may identify that the PDCCH scrambled by the C-RNTI is scheduled for retransmission, and the UE may perform retransmission of the PUSCH payload based on the scheduling on the PDCCH addressed to the C-RNTI. Otherwise, if the NDI is flipped (e.g., changed), the UE may perform a new transmission of the scheduled HARQ process (e.g., transmit new data in the HARQ process) according to the scheduling configuration received in the PDCCH. In this case, if the RA has been completed and the last RA attempt was made on CFRA resources, the HARQ buffer memory used to transmit the MAC PDU in the MsgA buffer memory (or Msg3 buffer memory) may be reserved to allow the UE to perform HARQ retransmissions.

[0143] b. Transmission or retransmission of MsgA payload based on previous NDI value

[0144] In some embodiments, if a subsequent scheduling on PDCCH addressed to C-RNTI for HARQ process 0 is received in response to MsgA transmission of the last RA attempt on CFRA resource, the UE can compare the NDI value received in the PDCCH with the NDI value set for previous transmission of the same HARQ process before the MsgA transmission. If the NDI is flipped (i.e., different from the previous NDI value), the UE can perform a new transmission of HARQ process 0 (e.g., transmission of new data in HARQ process 0) according to the scheduling configuration received in the PDCCH. Otherwise, if the NDI is not flipped (i.e., same as the previous NDI value), the UE can perform a retransmission of HARQ process 0 according to the scheduling configuration received in the PDCCH. In this case, if the RA has completed and the last RA attempt is on CFRA resource, the HARQ buffer memory for the transmitted MAC PDU in MsgA buffer memory (or Msg3 buffer memory) can be preserved to allow the UE to perform HARQ retransmission.

[0145] For example, HARQ process 0 can be scheduled with NDI value set to “0”, after which the UE can initiate a 2-step RA type random access procedure using CFRA resource. After transmitting MsgA, the UE can keep the HARQ buffer memory for the transmitted MAC PDU in MsgA buffer memory. If the NDI of the HARQ process 0 subsequent scheduling on PDCCH addressed to C-RNTI is “0”, the UE can compare the NDI of the subsequent scheduling with the NDI value of HARQ process 0 before the MsgA transmission (0 in this example), and the NDI is not flipped. The UE can perform a retransmission of HARQ process 0, otherwise if the received NDI is “1”, which indicates the NDI is flipped, the UE will consider this as scheduling of a new transmission, and can perform a new transmission of HARQ process 0 (e.g., transmission of new data in HARQ process 0) according to the scheduling configuration indicated in the PDCCH.

[0146] c. MsgA payload transmission or retransmission independent of whether CFRA or CBRA resource is used

[0147] In some embodiments, an initial value may be assigned for the NDI used for MsgA transmission, regardless of whether CFRA or CBRA resources are used for MsgA transmission. The initial value of NDI may be "0" or "1". The NDI value may be predefined in the protocol or broadcast in system information, or signaled via dedicated signaling. If the previous uplink grant delivered to the HARQ entity for the same HARQ process is an uplink grant determined according to a contention-free transmission protocol for MsgA or according to a contention-based transmission protocol for MsgA, and the C-RNTI is included in MsgA, an initial value may be used as the NDI of the previous MsgA transmission for NDI comparison. In this case, if the RA has been completed, the HARQ buffer memory used to transmit the MAC PDU in the MSGA buffer memory or the Msg3 buffer memory may be retained for the UE to perform retransmissions.

[0148] In the case where the preamble is successfully decoded but the corresponding PUSCH payload is not successfully decoded, some examples in any combination detailed above may be used for MsgA PUSCH payload retransmission.

[0149] C. MsgA transmission during RA

[0150] Now refer to Figure 4 , depicts a method 400 for transmitting MsgA during an RA procedure. The method 400 can be implemented or performed using any of the components described herein, such as the BS 102 or the UE 104. In general, the method 400 can include a CFRA configuration and a CBRA configuration as described above. The method 400 can include transmitting an RA preamble and a payload (405). The method 400 can include retransmitting the payload (410). The method 400 can include transmitting a response (415).

[0151] The method 400 can include transmitting a RA preamble and a payload (405). A wireless communication device (e.g., UE 104) can send, provide, or transmit a random access (RA) preamble and a corresponding uplink channel payload to a wireless communication node (e.g., BS 102) in a RA procedure. The wireless communication node can in turn identify, obtain, or receive the RA preamble and the corresponding uplink channel payload from the wireless communication device in the RA procedure. The RA preamble can be generated in accordance with the RA procedure, and the transmission resource of the preamble can include at least one of: a time domain transmission resource, a frequency domain transmission resource, a code domain transmission resource, a format, or a mapping relationship between the preamble and the payload transmission resource, etc. The uplink channel payload can contain or include at least one of: a C-RNTI, a UE identity, a MAC CE, a BSR, a CCCH message, a DCCC message, a PHR, a MAC SDU from a DRB, beam management related information, or other parameters to be transmitted via the uplink channel. The transmission resource of the uplink channel payload can include: a location of the payload transmission resource in time domain, a location of the payload transmission in frequency, a location of the payload transmission resource in code domain (e.g., orthogonal code, non-orthogonal code, or other code of physical layer), and a bandwidth for transmission, etc. The mapping relationship can include the following flexibility: the preamble transmission resource located in different random access channel occasions (ROs) can be mapped to the same payload transmission occasion with different payload transmission codes; different preambles within one RO can be mapped to different payload transmission occasions (using the same or different payload transmission codes); multiple UEs using different preambles can be mapped to the same payload transmission resource; the same payload transmission code within the same payload transmission occasion; one preamble resource (combination of preamble and RO) can be mapped to multiple payload transmission codes within one payload transmission occasion to enable multi-layer data transmission (e.g., MIMO); and the timing offset between the preamble transmission resource and the payload transmission resource can be different for different preamble transmission resources (e.g., same or next time slot).

[0152] In some embodiments, a wireless communication device can establish a medium access control (MAC) protocol data unit (PDU) based on the MsgA buffer memory. The corresponding uplink channel payload can be based on the MsgA buffer memory. The MAC PDU can contain a uniform length bit string (e.g., a multiple of 8 bits), such as one or more of the following: a common control channel (CCCH) message, a dedicated control channel (DCCH) message, a MAC service data unit (SDU) and MAC-CE, a C-RNTI, an inactive RNTI (I-RNTI), a UE-ID, a buffer status report (BSR), a power headroom report (PDR), a beam measurement result, and a beam failure indication, etc. The MAC PDU can be established when communicating with a wireless communication node. Each MsgA can include a RA preamble and a corresponding uplink channel payload. In some embodiments, a wireless communication node can cause a wireless communication device to establish a MAC PDU based on the MsgA buffer memory. In some embodiments, the corresponding uplink channel payload can be in the MAC PDU.

[0153] In some embodiments, in accordance with the transmission of the RA preamble and the corresponding uplink payload being on a CFRA resource and this being the last RA attempt, the wireless communication device can maintain (or preserve) a hybrid automatic repeat request (HARQ) buffer memory. The HARQ buffer memory can include the MAC PDU. HARQ can be a combination of high-speed forward error correction coding and automatic repeat request (ARQ) error control. The HARQ buffer memory can maintain the corresponding uplink payload to be transmitted by applying error correction coding. In some embodiments, a wireless communication node can cause a wireless communication device to maintain the HARQ buffer memory in accordance with the transmission of the RA preamble and the corresponding uplink payload being on a CFRA resource and this being the last RA attempt.

[0154] In some embodiments, a wireless communication device may identify, calculate, or determine an initial New Data Indicator (NDI) value for transmissions of a HARQ process that occurs prior to the last RA attempt for a transmission of an RA preamble and corresponding uplink channel payload to a wireless communication node on CFRA resources. The NDI may be used to define or identify whether a scheduling request from the wireless communication node to the wireless communication device is for an initial transmission (e.g., a new transmission) or a retransmission. The wireless communication device may determine whether the scheduling information is for a new transmission or a retransmission based on a comparison of an NDI value received in scheduling information (e.g., a PDCCH addressed to a C-RNTI, an UL grant in a RAR, or an UL grant in a fallback RAR) with the initial NDI value. The initial NDI value may be assigned to the same HARQ process. Alternatively, the wireless communication device may determine whether the scheduling information is for a new transmission or a retransmission by comparing an NDI value received in scheduling information (e.g., a PDCCH addressed to a C-RNTI, an UL grant in a RAR, or an UL grant in a fallback RAR) with a previous NDI value for the same HARQ process. If it is determined that the NDI value has not flipped, the received schedule may need to be retransmitted. If it is determined that the NDI value has flipped, the received schedule may need to be newly transmitted. The initial NDI value may be 0 or 1 and may be determined according to the protocol (e.g., specifying that the payload is transmitted via an uplink channel or RRC). In some embodiments, the wireless communication node may cause the wireless communication device to identify, calculate, or determine an initial new data indicator (NDI) value for a new NDI for a transmission of a HARQ process that occurs prior to the transmission of an RA preamble and corresponding uplink channel payload to the wireless communication node on a CFRA resource and that is the last RA attempt.

[0155] In some embodiments, a wireless communication device may correspond to a New Data Indicator (NDI) having an initial value when transmitting an RA preamble and corresponding uplink channel payload to a wireless communication node on CFRA resources, and this is the last transmission of an RA attempt. The NDI may be used to define or identify whether a communication from the wireless communication device is an initial transmission. In some embodiments, the NDI may be set according to a protocol. In some embodiments, when a RA preamble and corresponding uplink channel payload are transmitted on CFRA resources and this is the last transmission of an RA attempt, the wireless communication node may receive the RA preamble and corresponding uplink channel payload from the wireless communication node considered using the initial NDI value.

[0156] Method 400 may include retransmitting the payload (410). The wireless communication device may determine whether the initial transmission of the uplink channel payload was successful. In response to the wireless communication node successfully transmitting the uplink channel payload, the wireless communication may avoid retransmission of the uplink channel upload. Conversely, in response to a failure of the uplink channel payload transmitted by the wireless communication node, the wireless communication device may resend or retransmit the corresponding uplink channel upload to the wireless communication node via an uplink grant. The uplink grant may correspond to permission to transmit data, such as the uplink channel payload, via the uplink channel. The wireless communication node may then re-receive the corresponding uplink channel upload from the wireless communication device via the uplink grant.

[0157] In some embodiments, the wireless communication device can retransmit or retransmit the corresponding uplink channel payload by an uplink grant corresponding to the NDI when there is an initial NDI value. The wireless communication node can re-receive the corresponding uplink channel payload by an uplink grant corresponding to the NDI with the initial NDI value. In some embodiments, the wireless communication node can transmit a download channel addressed to the cell radio network temporary identifier (C-RNTI) to the wireless communication device. The C-RNTI may include a current NDI value (e.g., 0 or 1). In some embodiments, the wireless communication device can retransmit the corresponding uplink channel payload by an uplink grant of a downlink channel addressed to the C-RNTI. In some embodiments, the uplink grant may come from a downlink channel addressed to the cell radio network temporary identifier (C-RNTI). The wireless communication device can then receive a downlink channel transmission addressed to the C-RNTI from the wireless communication node.

[0158] In some embodiments, the wireless communication device determines whether the uplink channel payload retransmission by the wireless communication node is successful or failed according to whether the current NDI value is different from the initial (or previous) NDI value for the same HARQ process scheduled. In response to determining that the retransmission is successful, the wireless communication device can refrain from additional retransmissions and, if scheduled, can further perform a new transmission. Otherwise, in response to determining that the retransmission is failed, the wireless communication device can retransmit the corresponding uplink channel according to the scheduling. In some embodiments, the wireless communication device can compare the current NDI value with the initial (or previous) NDI value for the same HARQ process scheduled. When the current NDI value matches the initial (or previous) NDI value for the same HARQ process scheduled, the wireless communication device can retransmit or retransmit the corresponding uplink channel payload buffered in the buffer memory for the scheduled HARQ process (e.g., HARQ process 0). Conversely, when the current NDI value is different from the initial NDI value, the wireless communication device can initiate transmission based on a new scheduling for the scheduled HARQ process (e.g., HARQ process 0).

[0159] In some embodiments, in response to determining that the retransmission is failed, the wireless communication device can retransmit the corresponding uplink channel according to whether the value of the NDI is changed with respect to the initial (or previous) NDI value for the same HARQ process scheduled. In some embodiments, in response to receiving an uplink grant addressed to a C-RNTI and identifying a contention-free RA (CFRA) procedure for the RA procedure, the wireless communication device can retransmit or retransmit the corresponding uplink channel. The retransmission of the corresponding uplink channel can be according to whether the value of the NDI is changed with respect to the initial (or previous) NDI value for the same HARQ process scheduled. When the value of the NDI is not changed with respect to the initial (or previous) NDI value for the same HARQ process scheduled, the wireless communication device can retransmit the corresponding uplink channel payload buffered in the buffer memory for the scheduled HARQ process (e.g., HARQ process 0). Conversely, when the value of the NDI is changed with respect to the initial (or previous) NDI value for the same HARQ process scheduled, the wireless communication device can initiate transmission based on a new scheduling for the scheduled HARQ process (e.g., HARQ process 0).

[0160] In some embodiments, the wireless communication device may use a MAC PDU to retransmit or retransmit the corresponding uplink channel payload to the wireless communication device. For example, the wireless communication device may generate a MAC PDU to transmit the uplink channel payload to the wireless communication node. In some embodiments, the HARQ buffer memory may include a MAC PDU for retransmission. The wireless communication device may retransmit or retransmit the corresponding uplink channel payload using the MAC PDU retained in the HARQ buffer memory. In some embodiments, the wireless communication node may use the MAC PDU to re-receive the corresponding uplink channel payload from the wireless communication device. In some embodiments, the wireless communication device may retransmit or retransmit the corresponding uplink channel payload to the wireless communication node only once. The wireless communication node may re-receive the corresponding uplink channel payload from the wireless communication device only once.

[0161] In some embodiments, a wireless communication device may retransmit or retransmit a corresponding uplink channel payload to a wireless communication node using a redundancy version (RV). The RV may correspond to a redundant copy of the payload to be retransmitted and may be specified according to a specification. In some embodiments, the wireless communication device may rereceive the corresponding uplink channel payload from the wireless communication device using the RV.

[0162] Method 400 may include transmitting a response (415). In some embodiments, the wireless communication node may send or provide a transmission fallback RA response (RAR) (e.g., by including it in MsgB). In some embodiments, the wireless communication device may identify, retrieve, or receive the fallback RA response (RAR). The RAR may define or include an uplink grant to be used for retransmission of the corresponding uplink channel payload. The RA procedure may include or be identified as a contention-free RA (CFRA) procedure. In some embodiments, the fallback RAR may include an RV to be used for retransmission of the corresponding uplink channel payload.

[0163] Although various embodiments of the present solution have been described above, it should be understood that they are presented as examples only and not as limitations. Similarly, various figures may depict example architectures or configurations, which are provided to enable those of ordinary skill in the art to understand the example features and functions of the present solution. However, such persons will understand that the solution is not limited to the example architectures or configurations shown, but can be implemented using various alternative architectures and configurations. In addition, as those of ordinary skill in the art will understand, one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-described illustrative embodiments.

[0164] It should also be understood that any reference to an element herein using names such as "first," "second," etc. does not generally limit the number or order of those elements. Rather, these names may be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to a first element and a second element does not imply that only two elements may be used, or that the first element must precede the second element in some manner.

[0165] Furthermore, persons of ordinary skill in the art will appreciate that information and signals may be represented using any of a variety of different methods and techniques. For example, data, instructions, commands, information, signals, bits, and symbols, etc., as referenced in the above description, may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0166] Those of ordinary skill in the art will further understand that any of the various illustrative logical blocks, modules, processors, components, circuits, methods, and functions described in conjunction with the aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of the two), firmware, various forms of programs or design code incorporating instructions (which, for convenience, may be referred to herein as "software" or "software modules"), or any combination of these technologies. To clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been generally described above in terms of their functionality. Whether such functionality is implemented as hardware, firmware, software, or a combination of these technologies depends on the specific application and the design constraints imposed on the overall system. A skilled person may implement the described functionality in various ways for each specific application, but such implementation decisions do not result in a departure from the scope of this disclosure.

[0167] In addition, it will be understood by those skilled in the art that the various illustrative logic blocks, modules, devices, components, and circuits described herein may be implemented within or performed by an integrated circuit (IC), which may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, or any combination thereof. The logic blocks, modules, and circuits may also include an antenna and / or a transceiver to communicate with various components within a network or within a device. The general-purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other suitable configuration for performing the functions described herein.

[0168] If implemented in software, these functions can be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media include both computer storage media and communication media, including any medium capable of transferring a computer program or code from one place to another. The storage medium can be any available medium that a computer can access. By way of example and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage device, or any other medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0169] In this document, the term "module" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the relevant functions described herein. In addition, for the purpose of discussion, various modules are described as discrete modules; however, as is clear to one of ordinary skill in the art, two or more modules can be combined to form a single module that performs the associated functions according to embodiments of the present solution.

[0170] In addition, memory or other storage devices and communication components may be used in embodiments of the present solution. It should be understood that for clarity, the above description has described embodiments of the present solution with reference to different functional units and processors. However, it is clear that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without departing from the present solution. For example, functions illustrated as being performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. Therefore, references to specific functional units are merely references to appropriate means for providing the described functionality, rather than representing a strict logical or physical structure or organization.

[0171] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of this disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as set forth in the following claims.

Claims

1. A method for communication, comprising: The wireless communication device transmits a random access (RA) preamble and a corresponding uplink channel payload to the wireless communication node during a RA procedure; receiving, by the wireless communication device, a fallback RA response (RAR) from the wireless communication node, the fallback RAR comprising an uplink grant, a current new data indicator (NDI), and a redundancy version (RV) for a corresponding uplink channel payload, wherein the RA procedure comprises a contention-free RA (CFRA) procedure; comparing, by the wireless communication device, a current NDI value received in the fallback RAR with a previous NDI value; Building, by the wireless communication device, a medium access control (MAC) protocol data unit (PDU) based on a MsgA buffer and the current NDI value, wherein the corresponding uplink channel payload is based on the MsgA buffer; as well as The wireless communication device retransmits the corresponding uplink channel payload to the wireless communication node using the MAC PDU through the uplink grant and the RV according to whether the current NDI value is different from the previous NDI value.

2. The method according to claim 1, comprising: The corresponding uplink channel payload is retransmitted only once by the wireless communication device to the wireless communication node, wherein the uplink grant is from the fallback RA response (RAR).

3. The method according to claim 1, comprising: retransmitting, by the wireless communication device, the corresponding uplink channel payload to the wireless communication node via the uplink grant in response to a new data indicator (NDI) having an initial NDI value, wherein the uplink grant is from a fallback RA response (RAR); receiving, by the wireless communication device, from the wireless communication node a downlink channel addressed to a cell radio network temporary identifier (C-RNTI) including a current NDI value; In response to a failure of the retransmitted uplink channel payload to the wireless communication node, the wireless communication device retransmits the corresponding uplink channel payload according to whether the current NDI value is different from the initial NDI value.

4. The method according to claim 3, wherein: When the current NDI value matches the initial NDI value, the corresponding uplink channel payload buffered in a buffer memory of a hybrid automatic repeat request (HARQ) process 0 is retransmitted by the wireless communication device.

5. The method according to claim 3, wherein: When the current NDI value is different from the initial NDI value, the wireless communication device initiates transmission based on a new schedule of a hybrid automatic repeat request (HARQ) process 0. The method according to claim 3 , wherein the NDI is set according to a protocol.

7. The method according to claim 1, comprising: maintaining, by the wireless communication device, a hybrid automatic repeat request (HARQ) buffer memory based on the transmission of the RA preamble and the corresponding uplink channel payload, wherein the RA procedure comprises a contention-free RA (CFRA) procedure and the HARQ buffer memory comprises medium access control (MAC) protocol data units (PDUs); as well as The corresponding uplink channel payload in the MAC PDU is retransmitted by the wireless communication device to the wireless communication node.

8. The method according to claim 7, comprising: The corresponding uplink channel payload is retransmitted by the wireless communication device to the wireless communication node using the RV, wherein the RV includes a value indicated in the backoff RAR.

9. The method according to claim 7, comprising: retransmitting, by the wireless communication device, the corresponding uplink channel payload in the MAC PDU to the wireless communication node corresponding to the new data indicator NDI having an initial value; In response to a failure of the retransmitted uplink channel payload to the wireless communication node, the wireless communication device retransmits the corresponding uplink channel payload according to whether the value of the NDI has changed relative to the initial value.

10. The method according to claim 9, comprising: In response to a failure of the retransmitted uplink channel payload for the wireless communication node, the wireless communication device retransmits the corresponding uplink channel payload via an uplink grant of a downlink channel addressed to a cell radio network temporary identifier (C-RNTI).

11. The method according to claim 9, wherein: When the value of the NDI does not change from the initial value, the wireless communication device retransmits the corresponding uplink channel payload buffered in a buffer memory of a hybrid automatic repeat request (HARQ) process 0.

12. The method according to claim 9, wherein: When the value of the NDI changes relative to the initial value, the wireless communication device initiates transmission based on a new schedule of a hybrid automatic repeat request (HARQ) process 0. The method according to claim 9 , wherein the NDI is set according to a protocol.

14. The method according to claim 1, comprising: determining, by the wireless communication device, an NDI value as a previous New Data Indicator (NDI) value of a transmission in a Hybrid Automatic Repeat Request (HARQ) process that occurred before the transmission of the RA preamble and the corresponding uplink channel payload to the wireless communication node; receiving, by the wireless communication device, from the wireless communication node a downlink channel addressed to a cell radio network temporary identifier (C-RNTI) including a current NDI value; In response to a failure of the retransmitted uplink channel payload to the wireless communication node, the wireless communication device retransmits the corresponding uplink channel payload according to whether the current NDI value is different from the previous NDI value.

15. The method of claim 1, wherein the uplink grant is from a downlink channel addressed to a Cell Radio Network Temporary Identifier (C-RNTI).

16. The method according to claim 15, comprising: transmitting, by the wireless communication device corresponding to the new data indicator NDI having an initial value, the RA preamble and the corresponding uplink channel payload to the wireless communication node, the corresponding uplink channel payload being in the MAC PDU; as well as In response to a failure of an uplink channel payload transmitted to the wireless communication node, the wireless communication device retransmits the corresponding uplink channel payload to the wireless communication node based on whether the value of the NDI has changed relative to the initial value.

17. The method according to claim 16, wherein: When the value of the NDI does not change from the initial value, the wireless communication device retransmits the corresponding uplink channel payload buffered in a buffer memory of a hybrid automatic repeat request (HARQ) process 0.

18. The method according to claim 17, comprising: maintaining, by the wireless communication device, a HARQ buffer memory based on the transmission of the RA preamble and the corresponding uplink channel payload, the HARQ buffer memory comprising a medium access control (MAC) protocol data unit (PDU); as well as The corresponding uplink channel payload in the MAC PDU is retransmitted by the wireless communication device to the wireless communication node.

19. The method of claim 16, wherein: When the value of the NDI changes relative to the initial value, the wireless communication device initiates transmission based on a new schedule of a hybrid automatic repeat request (HARQ) process 0.

20. The method of claim 16, wherein the NDI is set according to a protocol.

21. The method according to claim 15, comprising: transmitting, by the wireless communication device corresponding to the new data indicator NDI having an initial value, the RA preamble and the corresponding uplink channel payload to the wireless communication node, the corresponding uplink channel payload being in the MAC PDU; as well as In response to receiving an uplink grant addressed to the C-RNTI, and in response to the RA procedure being a contention-free RA (CFRA) procedure, retransmitting, by the wireless communication device, the corresponding uplink channel payload based on whether the value of the NDI has changed relative to the initial value.

22. A method for communication, comprising: Receiving, by a wireless communication node, a random access (RA) preamble and a corresponding uplink channel payload from a wireless communication device during a RA procedure; transmitting, by the wireless communication node, a fallback RA response (RAR) to the wireless communication device, the fallback RAR comprising an uplink grant, a current new data indicator (NDI), and a redundancy version (RV) for a corresponding uplink channel payload, wherein the RA procedure comprises a contention-free RA (CFRA) procedure; causing, by the wireless communication node, the wireless communication device to compare a current NDI value received in the fallback RAR with a previous NDI value; causing the wireless communication device to build, by the wireless communication node, a medium access control (MAC) protocol data unit (PDU) based on a MsgA buffer and the current NDI value, wherein the corresponding uplink channel payload is based on the MsgA buffer; as well as The wireless communication node re-receives the corresponding uplink channel payload from the wireless communication device using the MAC PDU through the uplink grant and the RV of the fallback RAR according to whether the current NDI is different from the previous NDI value.

23. The method according to claim 22, comprising: A fallback RA response (RAR) including the uplink grant is transmitted by the wireless communication node to the wireless communication device, wherein the RA procedure comprises a contention-free RA (CFRA) procedure.

24. The method according to claim 22, comprising: causing, by the wireless communication node, the wireless communication device to build a medium access control (MAC) protocol data unit (PDU) based on a MsgA buffer, wherein the corresponding uplink channel payload is based on the MsgA buffer; as well as The corresponding uplink channel payload is re-received by the wireless communication node from the wireless communication device using the MAC PDU.

25. The method of claim 22, comprising: The corresponding uplink channel payload is re-received by the wireless communication node from the wireless communication device only once, wherein the uplink grant is from a fallback RA response (RAR).

26. The method of claim 22, comprising: re-receiving, by the wireless communication node, the corresponding uplink channel payload from the wireless communication device via the uplink grant corresponding to a new data indicator (NDI) having an initial NDI value, wherein the uplink grant is from a fallback RA response (RAR); transmitting, by the wireless communication node to the wireless communication device, a downlink channel addressed to a cell radio network temporary identifier (C-RNTI) including a current NDI value; as well as In response to a failure of the retransmitted uplink channel payload for the wireless communication node, the wireless communication node re-receives the corresponding uplink channel payload from the wireless communication device according to whether the current NDI value is different from the initial NDI value.

27. The method of claim 26, wherein: When the current NDI value matches the initial NDI value, the wireless communication node re-receives the corresponding uplink channel payload buffered in a buffer memory of a hybrid automatic repeat request (HARQ) process 0 from the wireless communication device.

28. The method of claim 26, wherein: When the current NDI value is different from the initial NDI value, the wireless communication node causes the wireless communication device to initiate transmission based on a new schedule of a hybrid automatic repeat request (HARQ) process 0. The method of claim 26 , wherein the NDI is set according to a protocol.

30. The method of claim 22, comprising: causing, by the wireless communication node, the wireless communication device to maintain a hybrid automatic repeat request (HARQ) buffer memory based on the transmission of the RA preamble and the corresponding uplink channel payload, the HARQ buffer memory comprising a medium access control (MAC) protocol data unit (PDU); as well as The corresponding uplink channel payload in the MAC PDU is re-received by the wireless communication node from the wireless communication device.

31. The method according to claim 30, comprising: The corresponding uplink channel payload is re-received by the wireless communication node from the wireless communication device using a redundancy version (RV), wherein the RV comprises a value indicated in a fallback RA response (RAR).

32. The method of claim 30, comprising: re-receiving, by the wireless communication node, the corresponding uplink channel payload in the MAC PDU from the wireless communication device, the wireless communication node corresponding to a new data indicator (NDI) having an initial value; In response to a failure of the retransmitted uplink channel payload for the wireless communication node, the wireless communication node re-receives the corresponding uplink channel payload from the wireless communication device according to whether the value of the NDI has changed relative to the initial value.

33. The method of claim 32, comprising: In response to the failure of the uplink channel payload retransmitted by the wireless communication node, the corresponding uplink channel payload is re-received by the wireless communication node from the wireless communication device through an uplink grant of a downlink channel addressed to a cell radio network temporary identifier (C-RNTI).

34. The method of claim 32, wherein: When the value of the NDI does not change from the initial value, the wireless communication node re-receives the corresponding uplink channel payload buffered in a buffer memory of a hybrid automatic repeat request (HARQ) process 0 from the wireless communication device.

35. The method of claim 32, wherein: When the value of the NDI does not change from the initial value, the wireless communication node causes the wireless communication device to initiate re-reception of the corresponding uplink channel payload buffered in a buffer memory of a hybrid automatic repeat request (HARQ) process 0.

36. The method of claim 32, wherein the NDI is set according to a protocol.

37. The method of claim 22, comprising: causing, by the wireless communication node, the wireless communication device to determine an initial NDI value for: a new data indicator (NDI) for a transmission of a hybrid automatic repeat request (HARQ) process occurring prior to the transmission of the RA preamble and the corresponding uplink channel payload to the wireless communication node; transmitting, by the wireless communication node to the wireless communication device, a downlink channel addressed to a cell radio network temporary identifier (C-RNTI) including a current NDI value; In response to a failure of the retransmitted uplink channel payload for the wireless communication node, the wireless communication node re-receives the corresponding uplink channel payload from the wireless communication device according to whether the current NDI value is different from the initial NDI value.

38. The method of claim 22, wherein the uplink grant is from a downlink channel addressed to a Cell Radio Network Temporary Identifier (C-RNTI).

39. The method of claim 38, comprising: receiving, by the wireless communication node from the wireless communication device, the RA preamble and the corresponding uplink channel payload destined for the wireless communication node, the corresponding uplink channel payload in the MAC PDU, the wireless communication node corresponding to a new data indicator (NDI) having an initial value; as well as In response to a failure of the uplink channel payload transmitted to the wireless communication node, the wireless communication node re-receives the corresponding uplink channel payload from the wireless communication device according to whether the value of the NDI has changed relative to the initial value.

40. The method of claim 39, wherein: When the value of the NDI does not change from the initial value, the wireless communication node re-receives the corresponding uplink channel payload buffered in a buffer memory of a hybrid automatic repeat request (HARQ) process 0 from the wireless communication device.

41. The method according to claim 40, comprising: causing, by the wireless communication node, the wireless communication device to maintain a HARQ buffer memory based on the transmission of the RA preamble and the corresponding uplink channel payload, the HARQ buffer memory comprising a medium access control (MAC) protocol data unit (PDU); as well as The corresponding uplink channel payload in the MAC PDU is retransmitted by the wireless communication device to the wireless communication node.

42. The method of claim 39, wherein: When the value of the NDI changes relative to the initial value, the wireless communication node causes the wireless communication device to initiate transmission based on a new schedule of a hybrid automatic repeat request (HARQ) process 0.

43. The method of claim 39, wherein the NDI is set according to a protocol.

44. The method of claim 38, comprising: receiving, by the wireless communication node from the wireless communication device, the RA preamble and the corresponding uplink channel payload destined for the wireless communication node, the corresponding uplink channel payload in the MAC PDU, the wireless communication node corresponding to a new data indicator (NDI) having an initial value; as well as In response to receiving an uplink grant addressed to the C-RNTI, and in response to the RA procedure being a contention-free RA (CFRA) procedure, re-receiving, by the wireless communication node, the corresponding uplink channel payload from the wireless communication device based on whether the value of the NDI has changed relative to the initial value.

45. A computer-readable storage medium storing instructions which, when executed by one or more processors, can cause the one or more processors to perform the method according to any one of claims 1 to 44.

46. ​​A wireless communication device comprising: one or more processors; as well as A memory storing executable instructions, which, when executed by the one or more processors, cause the one or more processors to perform the method according to any one of claims 1 to 21.

47. A wireless communication node, comprising: one or more processors; as well as A memory storing executable instructions, which, when executed by the one or more processors, cause the one or more processors to perform the method according to any one of claims 22 to 44.

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