System and method for coverage enhancement in non-terrestrial networks (NTNs)

Abstract

Systems and methods for coverage enhancement in a non-terrestrial network (NTN) are presented. A wireless communication device (e.g., a UE) may receive a random access response, RAR, from a wireless communication node (e.g., a BS), the RAR including an indication indicating at least a maximum number of repetitions, repNum, of the RAR of the wireless communication device. The wireless communication device may use the repNum to determine a time domain location of the transmission resource at which the RAR transmission Msg.3 will be responded.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, including but not limited to systems and methods for coverage enhancement in non-terrestrial networks (NTNs). Background Art

[0002] The Third Generation Partnership Project (3GPP), a standardization organization, is currently developing a new air interface called 5G New Radio (5G NR) and the Next Generation Packet Core Network (NG-CN or NGC). 5G NR will have three main components: 5G Access Network (5G-AN), 5G Core Network (5G GC) and User Equipment (UE). In order to facilitate the implementation of different data services and requirements, the elements of 5GC (also known as Network Functions) have been simplified, some of which are software-based and some are hardware-based, so that they can be adjusted as needed. Summary of the invention

[0003] The exemplary embodiments disclosed herein are intended to solve problems related to one or more problems existing in the prior art, as well as to provide additional features, which will become apparent 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 by way of example, rather than by way of limitation, and it will be apparent to those of ordinary skill in the art who have read this disclosure that various modifications may be made to the disclosed embodiments while remaining within the scope of this disclosure.

[0004] At least one aspect is directed to the following system, method, apparatus, or computer-readable medium. A wireless communication device (e.g., UE) may receive / obtain / acquire a random access response RAR transmission from a wireless communication node (e.g., a base station, a gNB, and / or a non-terrestrial device), the RAR transmission including an indication of a maximum number of repetitions repNum of the RAR transmission of at least the wireless communication device. The wireless communication device uses repNum to determine a time domain location of a transmission resource at which a Msg.3 transmission will be transmitted in response to the RAR transmission.

[0005] In some implementations, the indication may be in a 2-bit field. In some implementations, the indication may indicate that the wireless communication device will receive multiple RAR transmissions. In some embodiments, the value of repNum may be the same as the maximum number of repetitions configured or defined via system information block SIB signaling, radio resource control RRC signaling, or medium access control control element MAC CE signaling.

[0006] In some implementations, to determine the time domain position, the wireless communication device may use repNum to determine an offset; the wireless communication device may determine the time domain position by adding the offset to the position of the first or earliest RAR window of the RAR transmission.

[0007] In some implementations, the wireless communication device may determine the number of repetitions requiredRepNum_UE required by the wireless communication device by measuring a synchronization signal block SSB or one or more other signals; the wireless communication device determines the offset using repNum, requiredRedNum_UE, and the length of the RAR window.

[0008] In some implementations, the wireless communication device may determine the number of repetitions required by the wireless communication device, requiredRepNum_UE. When repNum matches (or is equal to) requiredRepNum_UE, the wireless communication device may use repNum or requiredRepNum_UE and the length of the RAR window to determine the offset.

[0009] In some implementations, the wireless communication node may send a Msg.4 transmission to only one of the plurality of wireless communication devices, each of which sent a Msg.3 transmission to the wireless communication node. In some implementations, the wireless communication device may determine a failure by a number of RAR detection attempts exceeding repNum; the wireless communication device may determine that a random access (e.g., performed or attempted by the wireless communication device) has failed in response to the failure.

[0010] In some implementations, the wireless communication device may send a Msg.3 transmission to the wireless communication node. The Msg.3 transmission includes an indication of an offset TC-RNTI_offset of a temporary cell radio network temporary identifier TC-RNTI, wherein the TC-RNTI is unique / specific to the wireless communication device. In some implementations, the wireless communication device determines a required number of repetitions requiredRepNum_UE for the wireless communication device. The value of TC-RNTI_offset may be the same as the value of requiredRepNum_UE, or may be a function of the value of requiredRepNum_UE.

[0011] In some implementations, the wireless communication node may scramble (e.g., encode or encrypt) the content of the Msg.4 transmission using TC-RNTI_offset in combination with TC-RNTI. In some implementations, the wireless communication device determines to use TC-RNTI_offset in combination with TC-RNTI as the cell radio network temporary identifier C-RNTI of the wireless communication device in response to: receiving a Msg.4 transmission from the wireless communication node; or, successfully descrambling (e.g., decoding or decrypting) the Msg.4 transmission using TC-RNTI_offset in combination with TC-RNTI; or, receiving an indication in the Msg.4 transmission from the wireless communication node, which verifies that TC-RNTI_offset in combination with TC-RNTI is used as the C-RNTI of the wireless communication device.

[0012] In some implementations, the wireless communication node may send a respective Msg. 4 transmission to each of a plurality of wireless communication devices that sent respective Msg. 3 transmissions to the wireless communication node.

[0013] At least one aspect is directed to the following system, method, apparatus, or computer-readable medium. A wireless communication node may send / transmit / provide a RAR transmission to at least one wireless communication device, the RAR transmission including an indication of a maximum number of repetitions repNum of the RAR transmission for at least the wireless communication device. The wireless communication device uses repNum to determine a time domain location of a transmission resource at which a Msg.3 transmission is to be transmitted in response to the RAR transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Various exemplary embodiments of the present solution are described in detail below with reference to the following drawings. The drawings or figures are provided for illustrative purposes only and only depict exemplary embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be considered as limiting the breadth, scope or applicability of the present solution. It should be noted that for clarity and ease of illustration, these drawings are not necessarily drawn to scale.

[0015] Figure 1 An example cellular communication network according to an embodiment of the present disclosure is shown, in which the techniques disclosed herein may be implemented;

[0016] Figure 2 A block diagram showing an example base station and user equipment device according to some embodiments of the present disclosure;

[0017] Figure 3 An example implementation of a non-terrestrial network NTN according to some embodiments of the present disclosure is shown;

[0018] Figure 4An example of access delay in communication between a UE and a BS according to some embodiments of the present disclosure is shown;

[0019] Figure 5 An example implementation in which one or more UEs send Msg.3 to a BS and one of the UEs receives a response from the BS according to some embodiments of the present disclosure is shown;

[0020] Figure 6 An example implementation of a UE sending Msg.3 to a BS and receiving a response from the BS according to some embodiments of the present disclosure is shown;

[0021] Figure 7 A flow chart of an example method for coverage enhancement in an NTN according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0022] 1. Mobile communication technology and environment

[0023] Figure 1 An example wireless communication network and / or system 100 is shown according to an embodiment of the present disclosure, in which the technology disclosed herein can be implemented in the cellular communication network. In the following discussion, the wireless communication network 100 can be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, referred to herein as "network 100". The example network 100 includes a base station (BS) 102 (hereinafter referred to as "BS102"; also called a wireless communication node) and a user equipment device 104 (hereinafter referred to as "UE 104"; also called a wireless communication device) that can 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. In 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 within its allocated bandwidth to provide adequate radio coverage to its intended users.

[0024] 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 through 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 implement the methods disclosed herein. According to various embodiments of the present solution, such communication nodes may communicate wirelessly and / or wired.

[0025] Figure 2 A block diagram of an example wireless communication system 200 for sending 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 functions that need not be described in detail herein. In an illustrative embodiment, as described above, the system 200 may be used in a wireless communication environment, such as the one described above. Figure 1 The system 200 generally includes a base station 202 (hereinafter referred to as "BS202") and a user equipment 204 (hereinafter referred to as "UE204"). The BS 202 includes a BS 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 and connected to each other through a data communication bus 220 as needed. The UE 204 includes a UE transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled and connected to each other through a data communication bus 240 as needed. The BS 202 communicates with the UE 204 through a communication channel 250, which can be any wireless channel described herein or other medium suitable for data transmission.

[0026] As those skilled in the art will appreciate, the system 200 may also include Figure 2Any number of modules outside the modules shown. It will be appreciated by those skilled in the art that the various illustrative blocks, modules, circuits, and processing logics described in connection with the embodiments disclosed herein can be implemented in hardware, computer-readable software, firmware, or any actual combination thereof. In order to clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps are generally described according to their functions. Whether such functions are implemented as hardware, firmware, or software depends on the specific application and design constraints imposed on the entire system. Those familiar with the concepts described herein can implement such functions in a manner suitable for each specific application, but such implementation decisions should not be interpreted as limiting the scope of the present disclosure.

[0027] According to some embodiments, the UE transceiver 230 is referred to herein as an "uplink" (UL) transceiver 230, which includes a radio frequency (RF) transmitter and an RF receiver, each of which includes a circuit coupled to an antenna 232. A duplex switch (not shown) can alternatively couple the uplink transmitter or receiver to the uplink antenna in a time duplex manner. Similarly, according to some embodiments, the BS transceiver 210 is referred to herein as a "downlink" (DL) transceiver 210, which includes an RF transmitter and an RF receiver, each of which includes a circuit coupled to an antenna 212. The downlink duplex switch can alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in a time duplex manner. The operation of the two transceiver modules 210 and 230 can be coordinated in time so that the uplink receiver circuit is coupled to the downlink antenna 232 so as to receive transmissions over the wireless transmission link 250 while the downlink transmitter is coupled to the downlink antenna 212. Instead, the operation of the two transceivers 210 and 230 may be coordinated in time such that the downlink receiver coupled to the downlink antenna 212 receives transmissions over the wireless transmission link 250 at the same time as the uplink transmitter coupled to the uplink antenna 232. In some embodiments, tight time synchronization with minimal guard times between changes in duplex direction is provided.

[0028] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250 and cooperate with an appropriately configured RF antenna array 212 / 232, which can support specific wireless communication protocols and modulation techniques. 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.

[0029] According to various embodiments, for example, BS202 can be an evolved node nodeB (eNB), a serving eNB, a target eNB, a femto station or a pico station. In some embodiments, UE 204 can be embodied 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 completed with general-purpose processors, content addressable memories, digital signal processors, application-specific integrated circuits, field programmable gate arrays, any suitable programmable logic devices, discrete gates or transistor logic, discrete hardware components, or any combination thereof to perform the functions described herein. In this way, 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, such as 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.

[0030] In addition, the steps of the methods or algorithms described with respect to the embodiments disclosed herein may be directly embodied in hardware, in firmware, in software modules executed by the processor modules 214 and 236, respectively, or in any practical combination thereof. The memory modules 216 and 234 may be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. In this regard, the memory modules 216 and 234 may be coupled to the processor modules 210 and 230, respectively, so that the processor modules 210 and 230 can read information from and write information to the memory modules 216 and 234, respectively. The memory modules 216 and 234 may also be integrated into their respective processor modules 210 and 230. In some embodiments, the memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during the execution of instructions executed by the processor modules 210 and 230, respectively. The memory modules 216 and 234 may also include non-volatile memory for storing instructions executed by the processor modules 210 and 230, respectively.

[0031] 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 limited to, the network communication module 218 provides an 802.3 Ethernet interface so that the base station transceiver 210 can communicate with a traditional Ethernet-based computer network. In this way, the network communication module 218 may include a physical interface for connecting to a computer network (e.g., a mobile switching center [Mobile Switching Center, MSC]). The terms "configured for", "configured to" and their conjunctions used herein for a specific operation or function refer to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted and / or arranged to perform a specific operation or function.

[0032] The Open Systems Interconnection (OSI) model (referred to herein as the "OSI model") is a conceptual and logical layout 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 its upper and upper layers. The OSI model also defines a logical network and effectively describes computer packet transmission 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 (NAS) layer or an Internet Protocol (IP) layer, and the seventh layer is other layers.

[0033] Various exemplary embodiments of the present solution are described below with reference to the accompanying drawings so that those of ordinary skill in the art can make and use the present solution. It is obvious to those of ordinary skill in the art that, after reading 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 exemplary embodiments and applications described and shown herein. In addition, the specific order or hierarchy of steps in the method disclosed herein is only an exemplary method. Based on design preferences, the specific order or hierarchy of the steps of the disclosed method or process can be rearranged while remaining within the scope of the present solution. Therefore, it will be understood by those of ordinary skill in the art that the methods and techniques disclosed herein present various steps or actions in an example order, and unless otherwise explicitly stated, the present solution is not limited to the specific order or hierarchy presented.

[0034] 2. System and method for coverage enhancement in NTN

[0035] In a non-terrestrial network NTN, UE 104 can obtain / get its position / orientation via a Global Navigation Satellite System (GNSS). A single UE 104 can be configured with different hardware and / or software components to support different capabilities for communicating with BS 102 and / or non-terrestrial components (e.g., satellites). Based on the capabilities of each UE 104, UE 104 is able to support a relatively high coverage area (e.g., a longer distance) or a relatively low coverage area (e.g., a shorter distance). Some UEs 104 (e.g., with relatively low capabilities) may encounter coverage issues, such as packet loss, network interference, etc., because the distance between UE 104 and at least one satellite or BS 102 is greater than its optimal coverage distance. In order to handle / solve potential coverage issues of certain systems, the systems and methods of the technical solutions discussed herein can utilize message repetition to improve the coverage performance of communications between UE 104 and BS 102 (and / or satellites). In addition, in some systems (e.g., terrestrial network systems), repetition of random access procedures including physical downlink control channels (PDCCH) may not support random access transmissions. Therefore, the systems and methods of the present technical solution may provide features or operations discussed herein to support methods for using repetition of random access responses (Random Access Responses, RARs) (e.g., including PDCCH) for random access transmissions to enhance / improve network coverage for UE 104 in the NTN.

[0036] Figure 3 An example structure of a transparent NTN according to some embodiments of the present disclosure is shown. The link between a UE (e.g., user equipment, UE 104, UE 204, mobile device, wireless communication device, terminal, etc.) and a satellite may be a service link. The link between a BS (e.g., base station, BS102, BS202, gNB, eNB, wireless communication node, etc.) and a satellite may be a feeder link and may be common to all UEs in the same cell. In order to improve / enhance the coverage performance of a UE 104 in an NTN, the systems and methods discussed herein may implement periodic repetition or multiple repetitions of transmission of a RAR (e.g., PDCCH).

[0037] In various configurations to improve coverage enhancement, the systems and methods may extend the RAR window (e.g., the duration of receiving a response from BS 102) of Msg. 2 (e.g., sometimes referred to as RAR), for example, additionally or alternatively enabling transmission repetitions. For example, to extend the RAR window, the network (e.g., BS 102, gNB, satellite, etc.) may indicate / send / provide the number of repetitions of the RAR to UE 104. UE 104 may determine / calculate one or more extended RAR windows based on the product of the original (or currently configured) RAR window and the number of repetitions of the RAR (e.g., multiplying the original RAR window by the number of repetitions). In another example, to extend the RAR window, the network may indicate to UE 104 the number of RAR repetitions and the period / cycle / duration between each PDCCH repetition. In this case, UE 104 may extend the RAR window by an offset. For example, the offset may be the product of the number of repetitions and the repetition period.

[0038] UE 104 may be located at a certain elevation angle (e.g., distance and / or direction) relative to satellite and / or BS 102. Based on the location of UE 104, satellite and / or BS 102, UE 104 may encounter different path losses, packet loss, interference and / or other signal propagation errors. Therefore, it may be desirable to repeat certain transmissions to UE 104 to enhance (e.g., signal or communication) coverage. Since the capabilities (e.g., channel environment) supported by each UE 104 are different, some UE 104 may wish or expect more or less transmission repetitions to mitigate performance losses. In some cases, some UE 104 with relatively high capabilities may not wish to repeat transmissions, or may expect a single transmission. Therefore, different UEs 104 may be configured with different repetition configurations (e.g., repNum, corresponding to the maximum number of repetitions [Maximum Repetition Number, repNum]).

[0039] In the case where each UE 104 has a different repetition configuration (e.g., for UE1 and UE2, repNum_UE1 < repNum_UE2), if multiple UEs 104 simultaneously send / transmit / signal / transfer the same random access preamble sequence with the same preamble index on the same time-frequency resource to BS102, BS 102 can detect different peaks / signals (e.g., the correlation or other operations of BS 102 or the satellite on the random access sequence), but can identify the different peaks as random access requests from one UE 104. For example, depending on the distance between UE 104 and BS 102 or the satellite, the positions of the peaks obtained by BS 102 or the satellite may have a certain (different) deviation. Therefore, in order for BS102 to accurately / distinguish clearly multiple UEs 104 transmitting random access requests, multiple UEs 104 can use different random access sequences to initiate random access. To provide an example here, in communication with one or more satellites and / or BS102, UE1 can represent the first UE and UE2 can represent the second UE. UE1 and UE2 can be in the same cell.

[0040] Reference Figure 4 , an example of the access delay of the communication between UE 104 and BS 102 is depicted. In the above case, if the number of repetitions configured by the network is repNum_UE1 (e.g., a predetermined number of repetitions similar to the maximum number of repetitions of UE1), and UE2 expects more repetitions than UE1 (e.g., repNum_UE2 > repNum_UE1), then UE2 may not be able to decode the RAR (e.g., Msg.2) from BS 102 (e.g., because there are fewer repetitions than the expected number of repetitions), resulting in an access failure for UE2. Therefore, by configuring a relatively large number of repetitions, premature access failures of UE2 (or other UEs 104 with similar or lower capabilities) can be alleviated or avoided. For example, if the number of repetitions is configured as repNum_UE2, then UE1 and UE2 rely on contention-based random access. However, since some UEs 104 (e.g., UE1) can meet the coverage criteria with fewer repetitions (e.g., fewer transmission times from BS 102) compared to the number of repetitions configured by BS 102 (e.g., repNum_UE2 in this case), the access delay of some UEs 104 may increase, as Figure 4 shown. The systems and methods of this technical solution can perform the features or operations discussed herein to enhance the coverage of the access network (e.g., through transmission repetition), while minimizing or avoiding the access delay of a single UE 104 (e.g., a UE 104 with relatively high capabilities and / or a lower repNum compared to the repNum configured by the network).

[0041] In various implementations, the UE 104 may measure a synchronization signal block (SSB) or one or more other signals sent / provided / transmitted by the network (e.g., BS 102 and / or satellite). The UE 104 may utilize the measurement of the signal to calculate / figure out or determine the number of repetitions that meet the desired coverage (e.g., coverage requirement or standard). The calculated number of repetitions that meet the coverage may be named / indicated / referred to as "requireRepNum_UEx", where, for example, "UEx" may represent the corresponding UE 104 that performs the calculation, e.g., UE1, UE2, etc. For UEs 104 with different coverage requirements (e.g., more or fewer repetitions), the following related definitions may be provided:

[0042] 1) The desired / required PDCCH repetition number for UE1 may be referred to as "requireRepNum_UE1". The required PDCCH repetition number for UE2 may be referred to as "requireRepNum_UE2".

[0043] 2) The uplink UL grant time-frequency resources indicated / notified in the first RAR (eg, Msg. 2) received in the initial RAR window (w1) may be initial resources.

[0044] 3) The maximum number of repetitions may be configured or predefined by at least one of (System Information Block, SIB) signaling, Radio Resource Control (Radio Resource Control, RRC) signaling, and / or Media Access Control (Media Access Control, MAC) signaling. The UE 104 may use the maximum number of repetitions to avoid a permanent state in which the UE 104 detects or monitors the RAR. In response to detecting the number of received transmissions corresponding to requireRepNum_UEx (e.g., the required number of repetitions configured by the network), the UE 104 may merge / combine (during repeated transmissions of the RAR) and decode the RAR. In some implementations, in response to receiving the number of transmissions corresponding to the maximum number of repetitions configured for the UE 104, the UE 104 may merge and decode the RAR. In some cases, if the decoding of the RAR fails, the UE 104 may declare / notify / indicate that the random access has failed and / or the random access is re-initiated / restarted to avoid the UE 104 being in a permanent state of detecting the RAR (in a state of attempting to successfully decode the RAR).

[0045] In a situation where multiple UEs 104 (e.g., two UEs 104 provided herein as examples) with different coverage requirements (e.g., based on the capabilities of the respective UEs 104) simultaneously send / transmit / signal the same random access preamble sequence to the network (e.g., BS 102 and / or satellite) on the same time-frequency resources, the network may repeatedly transmit the same RAR to the UEs 104 to avoid / minimize potential coverage issues.

[0046] Example Implementation 1

[0047] In various configurations, the UE 104 may receive a Msg.2 transmission or a RAR transmission from the BS 102. In this document, the terms "message Msg.2 transmission" and "RAR transmission" may be applicable to each other and / or used interchangeably. The RAR transmission may include a bit field (e.g., an indication) that indicates the maximum number of repetitions (repetitionNumber, repNum) of the RAR transmission to be transmitted to the UE 104. The RAR (e.g., a bit field of the RAR including RepNum) may be used to indicate a UL grant time-frequency resource offset (e.g., an implicit indication). For example, the RAR transmission may include a 2-bit field (e.g., the indication may be in a 2-bit field) for indicating the maximum number of repetitions for the UE 104, wherein the two bits (e.g., represented as "xx") may indicate that the UE 104 expects to receive multiple RAR transmissions.

[0048] In various implementations, the value of repNum may be the same as the maximum number of repetitions, which is configured or predefined via at least one of synchronization signal block (SIB) signaling, RRC signaling, and / or media access control element (MAC CE) signaling from BS 102 and / or satellite. For example, the repNum indicated / provided / sent via RAR transmission may correspond to the configured maximum number of repetitions (e.g., previously / historically sent by the BS via RRC or other signaling, and / or stored by UE 104).

[0049] In some implementations, if repNum is different from the predefined maximum number of repetitions, UE 104 may determine to use one of the following, the repNum most recently received via RAR transmission or the predefined maximum number of repetitions historically / previously received from BS 102, e.g., according to the configuration of UE 104. In some configurations, the predefined / configured maximum number of repetitions may not exist or may not be notified / indicated to UE 104 (e.g., not provided by BS 102 via at least one of the signaling). In this case, the condition that repNum is equal to the predefined / configured maximum number of repetitions may not apply.

[0050] The transmission resource corresponding to Msg.3 (Message 3) may include an indication of a resource offset. For UE1 and UE2 (and other UEs 104) with different coverage requirements, requireRepNum_UE1 may be configured for UE1, requireRepNum_UE2 may be configured for UE2, and a maximum number of repetitions (repNum) may be configured / provided in the RAR.

[0051] In response to UE1 receiving at least one RAR transmission from BS 102 (e.g., gNB or wireless communication node) (e.g., two repetitions of UE1 E2 in this example), UE1 may send / provide Msg.3 to BS 102 on the time-frequency resource according to an offset of (requireRepNum_UE1-1)×RARWindowLength corresponding to the UL grant time-frequency resource position received in the first RAR window (e.g., after a duration calculated by the following). In response to UE2 receiving at least one RAR transmission from BS 102 (e.g., four repetitions of UE2 in this example), UE2 may send Msg.3 to BS 102 on the time-frequency resource according to an offset of (requireRepNum_UE2-1)×RARWindowLength. RARWindowLength (e.g., the length / duration of the RAR window) may be provided to UE 104 by the network through RRC signaling, SIB signaling, and other types of signaling.

[0052] According to the above formula, UE 104 can use at least one of repNum, requiredRepNum_UEx and / or the length of the RAR window and other variables related to the time domain position of Msg.3 transmission to determine the offset of the time domain position (for example, by adding the position and offset of the earliest RAR window of the RAR transmission). In some cases, repNum can be the requiredRepNum_UEx of the corresponding UE 104 receiving the RAR transmission. When repNum=requireRepNum_UEx, the corresponding UE 104 (for example, UEx) can send Msg.3 on the time frequency resource according to the offset of ([repNum or requiredRepNumuex]-1)×RARWindowLength corresponding to the UL grant time frequency resource position received in the first RAR window. In this case, for example, when repNum matches (or is equal to) requiredRepNum_UEx, UE 104 may use repNum or requiredRepNum_UEx and the length of the RAR window to determine the offset of the time domain position.

[0053] In various implementations, the BS 102 may reply / respond to the Msg.3 transmission of (only) one UE 104 (e.g., a UE 104 that may adopt / obtain a Temporary Cell Radio Network Temporary Identifier [TC-RNTI] as its unique C-RNTI) to avoid potential confusion for multiple UEs 104 that adopt the same TC-RNTI (e.g., if the BS instead replies to each of these multiple UEs). Figure 5 In the example in FIG. 1 , BS 102 may respond to a Msg. 3 transmission of one of the plurality of UEs 104 (eg, UE1 in this example) (eg, transmitting a Msg. 4 [Message 4] transmission).

[0054] refer to Figure 5, depicts an example implementation in which multiple UEs 104 (e.g., UE1 and UE2) send Msg.3 to BS 102 and then one of the multiple UEs 104 receives a response (e.g., Msg.4) from BS 102 and / or a satellite. As shown, UE1 may need / determine requireRepNum_UE1 to be 2 times (e.g., requireRepNum_UE1=2) to transmit to meet the coverage requirement, and UE2 may need / determine requireRepNum_UE2 to be 2 times (e.g., requireRepNum_UE1=4) to transmit to meet the coverage requirement. The bit field in the RAR indicating the maximum number of repetitions for UE 104 may be repNum=4.

[0055] In this example, UE1 may send Msg.3 on a time-frequency resource with an offset of (2-1)×RARWindowLength corresponding to the UL grant time-frequency resource position being received in the first RAR window, for example, the offset may be simply expressed using the formula (requireRepNum_UEx-1)×RARWindowLength. Further, UE2 may send Msg.3 on a time-frequency resource with an offset of (4-1)×RARWindowLength corresponding to the UL grant time-frequency resource position received in the first RAR window, for example, the offset may be expressed using the formula ([repNum or requirerepNumex]-1)×RARWindowLength because repNum=requireRepNumUEx. As shown in this example, BS102 may send a response (e.g., a Msg.4 transmission) to only one of the multiple UEs 104, each of which has sent a Msg.3 transmission to BS102. For example, given the repNum configuration of BS 102 in the RAR message, BS 102 may perform blind detection in response to receiving Msg. 3 from UE 104 to detect Msg. 3 sent from multiple UEs 104 having different coverage requirements (eg, different times).

[0056] In some implementations, the UE 104 may detect that the number of RAR transmissions exceeds a predefined maximum number of repetitions (repNum) (e.g., the number of failed Msg.2 detection attempts exceeds repNum). In response to the detection / failure, the UE 104 may determine that random access has failed. After a previous random access failure, the UE 104 may retry the random access procedure to access the network.

[0057] Example Implementation 2

[0058] In various arrangements, a bit field included in the RAR may indicate / provide a maximum number of repetitions repNum for the UE 104. The bit field may be used to at least implicitly indicate a UL grant time-frequency resource offset (e.g., relative to w1, the first RAR window of Msg.2). Based on the indication from the bit field, the bit field may enable / allow the BS 102 to perform a Msg.4 transmission in response to receiving a Msg.3 from a different UE 104 that has configured multiple RAR repetition transmission responses. The Msg.3 transmission may include a bit field (e.g., an indication) indicating a value or offset of a "TC-RNTI_offset" that is specific / unique to the UE 104 that sent the Msg.3 transmission. The offset (e.g., TC-RNTI_offset) indicated by the bit field of the Msg.3 transmission may be associated with (e.g., be a function of) the required number of repetitions (requireRepNum_UEx). In some cases, TC-RNTI_offset may include a value that is the same as the value of the required number of repetitions (e.g., requireRepNum_UEx). Subsequently, BS 102 may scramble (e.g., encode or encrypt) Msg.4 (e.g., the content of Msg.4 transmission) using a combination of TC-RNTI and TC-RNTI_offset (e.g., TC-RNTI+TC-RNTI_offset). In this case, UE 104 may descramble (e.g., decode or decrypt) Msg.4 transmission using a similar combination of TC-RNTI+TC-RNTI_offset to confirm / verify / complete / confirm the upgrade / enhancement / update of "TC-RNTI+TC-RNTI_offset" to the Cell Radio Network Temporary Identifier (C-RNTI) or identifier of UE 104.

[0059] In some implementations, the Msg.4 transmission may include 1 bit (e.g., in a bit field) to confirm / verify / indicate the upgrade of "TC-RNTI+TC-RNTI_offset". For example, the 1 bit or bit field may include "1" (or "0", depending on the transmission configuration) to indicate that the upgrade of "TC-RNTI+TC-RNTI_offset" is confirmed, or include a different value to indicate that the upgrade is rejected or not confirmed.

[0060] For example, the TC-RNTI_offset may be sent / provided / indicated in a Msg.3 transmission. The confirmation message may be sent explicitly or implicitly in a corresponding Msg.4 transmission (in response to the Msg.3 transmission). The method or operation of confirming that the UE 104 can update the TC-RNTI with the offset may include one of the following:

[0061] i) When UE 104 (eg, UEx) receives the Msg.3 reply / response (eg, Msg.4 transmission) from BS 102, UE 104 may confirm that the TC-RNTI may be updated to the TC-RNTI with the offset.

[0062] ii) If UE 104 can successfully descramble Msg. 4 using "TC-RNTI + TC-RNTI_offset", UE 104 can confirm or establish "TC-RNTI + TC-RNTI_offset" as its C-RNTI.

[0063] iii) If UE 104 may receive Msg. 4 with a 1-bit indicator from BS 102 indicating confirmation (eg, instead of or instead of an indication of failure or rejection), UE 104 may confirm "TC-RNTI+TC-RNTI_offset" as its C-RNTI.

[0064] refer to Figure 6 , depicts an example implementation in which UE 104 sends Msg.3 to BS 102 and receives a response from BS 102, respectively. In various implementations, a 2-bit field for a maximum number of repetitions (repNum) may be configured or defined, wherein the two bits ("xx") may indicate that UE 104 expects to receive multiple RAR transmissions. The transmission resources (e.g., time domain location) of Msg.3 may be based on a resource offset associated with the bit field indicator RAR transmission. For UE1 and UE2 having different coverage requirements, requireRepNum_UE1 may be determined for UE1, requireRepNum_UE2 may be determined for UE 2, and the maximum number of repetitions (repNum) may be configured in the RARs received by UE1 and UE2.

[0065] After receiving the RAR transmission, UE1 may send Msg.3 on the time-frequency resources according to an offset of (requireRepNum_UE1-1)×RARWindowLength corresponding to the UL grant time-frequency resource position received in the first RAR window (e.g., after a duration calculated as follows), and UE1 may send Msg.3 on the time-frequency resources according to an offset of (requireRepNum_UE2-1)×RARWindowLength corresponding to the UL grant time-frequency resource position received in the first RAR window (e.g., after a duration calculated as follows). When repNum=requireRepNum_UEx, UEx may send Msg.3 on the time-frequency resources according to an offset of ([repNum or requireRepNum_UEx]-1)×RARWindowLength corresponding to the UL grant time-frequency resource position received in the first RAR window. BS 102 may receive Msg.3 transmissions from UE1 and UE2. In response to receiving the Msg.3 transmission from different UEs 104, BS 102 may send Msg.4 transmissions to UE1 and UE2, respectively (e.g., at different time domain locations). After receiving the Msg.4 transmission in response from BS 102, UE 104 may convert, establish, or utilize "TC-RNTI+TC-RNTI_offset" (e.g., or some other function / combination of TC-RNTI and TC-RNTI_offset) as its C-RNTI, for example, to complete the random access procedure and improve channel capacity or coverage.

[0066] Figure 7 A flowchart of an example method 700 for coverage enhancement in an NTN is shown. The method 700 may be used in conjunction with the present invention. Figures 1 to 6 In short, in some embodiments, the method 700 may be performed by at least one wireless communication device (e.g., UE or terminal device), at least one wireless communication node (e.g., BS, gNB or access network device), at least one satellite, etc. In some embodiments, additional, fewer or different operations may be performed in the method 700 according to the present embodiment. At least one aspect of the operation is directed to a system, method, apparatus, or computer-readable medium.

[0067] At operation 702, the wireless communication node may send / transmit / transmit a RAR transmission to at least one wireless communication device (or multiple wireless communication devices). The RAR transmission may include an indication of a maximum number of repetitions repNum of the RAR transmission for at least the wireless communication device and other wireless communication devices (e.g., all UEs). At operation 704, the wireless communication device may receive / obtain / acquire the RAR transmission from the wireless communication node.

[0068] In some configurations, the indication may be in a 2-bit field included / indicated / provided in the RAR transmission. In some cases, the indication may be used to indicate that the wireless communication device (e.g., expects) to receive multiple RAR transmissions (e.g., repetitions of the RAR transmission). In some implementations, repNum may include or be associated with the same value as the maximum number of repetitions, where the maximum number of repetitions may be configured or defined via system information block SIB signaling, radio resource control RRC signaling, and / or medium access control control element MAC CE signaling, as well as other types of signaling.

[0069] At operation 704, the wireless communication device may use at least the repNum to determine a time domain location of a transmission resource at which a Msg.3 transmission is to be transmitted in response to the RAR transmission.

[0070] In various configurations, the wireless communication device may determine the time domain position based on an offset (e.g., a resource offset or a time domain offset). For example, the wireless communication device may use repNum to determine the offset. In some cases, the value of the offset may correspond to the value of repNum. In some other cases, the wireless communication device may use repNum as part of a function to determine the value of the offset. In response to determining the offset, the wireless communication device may determine the time domain position, for example, by adding the offset to the position of the earliest random access response RAR window of the RAR transmission.

[0071] In some configurations, the wireless communication device may determine the number of repetitions requiredRepNum_UE required by the wireless communication device through or based on measurements of a synchronization signal block SSB and / or one or more other signals. In this case, the wireless communication device may use requiredRepNum_UE and the length of the RAR window to determine the offset.

[0072] In some implementations, the wireless communication device may determine the number of repetitions requiredRepNum_UE required by the wireless communication device. In this case, repNum (e.g., the value of repNum) may be the same as or match requiredRepNum_UE (e.g., the value of requiredRepNum of the corresponding wireless communication device). When repNum=requiredRepNum_UE, the wireless communication device may determine the offset using a method / function / formula using repNum or requiredRepNum_UE and the length of the RAR window.

[0073] In some implementations, the wireless communication device may send a Msg.4 transmission to only one of the multiple wireless communication devices, each of which sent a Msg.3 transmission to the wireless communication node. In some implementations, the wireless communication device may determine failure by a number of RAR detection attempts exceeding repNum (e.g., the number of times the wireless communication device attempted to detect RAR exceeded a maximum number of repetitions). In response to the failure of the number of RAR detection attempts, the wireless communication device may determine that random access has failed.

[0074] In various configurations, the wireless communication device may send a Msg.3 transmission to the wireless communication node. The Msg.3 transmission may include an indication of an offset TC-RNTI_offset of a temporary cell radio network temporary identifier TC-RNTI. The TC-RNTI_offset may be unique to the wireless communication device, for example, different from the TC-RNTI_offset of other wireless communication devices. In some cases, the wireless communication device may determine a required number of repetitions requiredRepNum_UE for the wireless communication device. The value of TC-RNTI_offset may be the same as the value of requiredRepNum_UE, or a function of the value of requiredRepNum_UE.

[0075] In various implementations, the wireless communication node may scramble the content of the Msg.4 transmission using TC-RNTI in combination with TC-RNTI_offset (e.g., according to TC-RNTI+TC-RNTI_offset). In this case, the wireless communication device may determine whether to adopt / use TC-RNTI in combination with TC-RNTI_offset as the cell radio network temporary identifier C-RNTI of the wireless communication device. For example, the wireless communication device may determine to adopt TC-RNTI in combination with TC-RNTI_offset as its C-RNTI (e.g., in the cell of the BS) in response to at least one of the following: i) the wireless communication device (successfully) receives a Msg.4 transmission from the wireless communication node (e.g., in response to its Msg.3 transmission); ii) the wireless communication device successfully descrambles the Msg.4 transmission using TC-RNTI in combination with TC-RNTI_offset; and / or iii) the wireless communication device receives an indication in a Msg.4 transmission from the wireless communication node, which verifies / confirms / approves the adoption of TC-RNTI in combination with TC-RNTI_offset as the C-RNTI of the wireless communication device.

[0076] In some implementations, the wireless communication node may send a respective Msg.4 transmission to each of the respective wireless communication devices, each of which has sent a respective Msg.3 transmission to the wireless communication node. Thus, the wireless communication devices that have sent the Msg.3 transmission to the wireless communication node may complete the random access procedure respectively (and use a C-RNTI unique to each wireless communication device).

[0077] Although various embodiments of the present solution have been described above, it should be understood that they are given only in an exemplary and non-limiting manner. Similarly, various figures can depict example architectures or configurations, and these example architectures or configurations are provided to enable those of ordinary skill in the art to understand the exemplary features and functions of the present solution. However, it will be understood by those of ordinary skill in the art that the present solution is not limited to the example architectures or configurations shown, but can be implemented using a variety of alternative architectures and configurations. In addition, as those of ordinary skill in the art understand, one or more features of an embodiment can 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-mentioned exemplary embodiments.

[0078] It should also be understood that any reference to an element using names such as "first", "second", etc. herein does not generally limit its quantity or order. Instead, 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 and a second element does not indicate that only two elements may be used, or that the first element must be located before the second element in some manner.

[0079] In addition, those skilled in the art will appreciate that information and signals may be represented using any of a variety of different techniques. For example, data, instructions, commands, information, signals, bits, and symbols 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.

[0080] Those of ordinary skill in the art will further understand that any of the various illustrative logical blocks, modules, processors, devices, circuits, methods, and functions described in connection with various aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of both), firmware, various forms of programs or design code containing instructions (for convenience, referred to herein as "software" or "software modules"), or any combination of these technologies. In order to clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functions. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these technologies, depends on the specific application and the design constraints imposed on the overall system. Those of ordinary skill in the art may implement the described functionality in various ways for each specific application, but such implementation decisions will not cause a departure from the scope of the present disclosure.

[0081] In addition, it will be understood by those of ordinary skill in the art that the various illustrative logic blocks, modules, devices, components and circuits described herein may be implemented in an integrated circuit (IC) or performed by an IC circuit, 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 further include antennas and / or transceivers to communicate with various components within a network or within a device. A general purpose processor may be a microprocessor, but alternatively, 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 combined with a DSP core, or any other suitable configuration to perform the functions described herein.

[0082] If implemented in software, these functions may be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein may be implemented as software stored on a computer-readable medium. Computer-readable media include computer storage media and communication media, and communication media include any media that enables a computer program or code to be transferred from one place to another. The storage medium can be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, and any other medium that can be used to store the required program code in the form of instructions or data structures and can be accessed by a computer.

[0083] As used herein, the term "module" 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, it is obvious to a person skilled in the art that two or more modules can be combined to form a single module that performs the relevant functions of the implementation according to the present solution.

[0084] In addition, memory or other memory and communication components can be used in the implementation of the present solution. It should be understood that, for the sake of clarity, the above description has described the implementation of the present solution with reference to different functional units and processors. However, it will be apparent that any appropriate functional distribution between different functional units, processing logic elements or domains can be used without departing from the present solution. For example, the functions performed by a separate processing logic element or controller shown in the figure can be performed by the same processing logic element or controller. Therefore, reference to a specific functional unit is only a reference to a suitable device that provides the described function, rather than a strict logical or physical structure or organization.

[0085] Various modifications to the embodiments described in this disclosure will be 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, this 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 described in the following claims.

Claims

1. A method comprising: The wireless communication device receives a random access response RAR from a wireless communication node, the RAR including an indication of a maximum number of repetitions repNum of the RAR of at least the wireless communication device; as well as The wireless communication device uses the repNum to determine the time domain position of the transmission resource, at which Msg.3 will be transmitted in response to the RAR.

2. The method according to claim 1, wherein: The indication is in a 2-bit field.

3. The method according to claim 1, wherein: The indication indicates that the wireless communication device will receive multiple RARs.

4. The method according to claim 1, wherein: The value of the repNum is the same as the maximum number of repetitions configured or defined through system information block SIB signaling, radio resource control RRC signaling, or medium access control element MAC CE signaling.

5. The method according to claim 1, wherein: Determining the time domain position includes: The wireless communication device determines an offset using the repNum; and The wireless communication device determines the time domain position by adding the offset to the position of the earliest RAR window of the RAR.

6. The method according to claim 5, comprising: The wireless communication device determines the number of repetitions requiredRepNum_UE required by the wireless communication device by measuring a synchronization signal block SSB or one or more other signals; as well as The wireless communication device determines the offset using the requiredRepNum_UE and the length of the RAR window.

7. The method according to claim 5, comprising: The wireless communication device determines a number of repetitions requiredRepNum_UE required by the wireless communication device; as well as When the repNum matches the requiredRepNum_UE, the wireless communication device determines the offset using the repNum or the requiredRepNum_UE and the length of the RAR window.

8. The method according to claim 1, wherein: The wireless communication node sends Msg. 4 to only one of a plurality of wireless communication devices, each of which sends Msg. 3 to the wireless communication node.

9. The method according to claim 1, comprising: The wireless communication device determines failure by a number of RAR detection attempts exceeding the repNum; as well as The wireless communication device determines, in response to the failure, that random access has failed.

10. The method according to any one of claims 1 to 7 and 9, comprising: The wireless communication device sends Msg.3 including an indication of an offset TC-RNTI_offset of a temporary cell radio network temporary identifier TC-RNTI to the wireless communication node, the TC-RNTI_offset being unique to the wireless communication device.

11. The method according to claim 10, comprising: The wireless communication device determines the number of repetitions requiredRepNum_UE required by the wireless communication device, The value of the TC-RNTI_offset is the same as the value of the requiredRepNum_UE, or is a function of the value of the requiredRepNum_UE.

12. The method according to claim 10, wherein: The wireless communication node scrambles the content of Msg.4 using the TC-RNTI_offset in combination with the TC-RNTI.

13. The method according to claim 12, comprising: The wireless communication device determines to use the TC-RNTI_offset combined with the TC-RNTI as the cell radio network temporary identifier C-RNTI of the wireless communication device in response to: receiving the Msg.4 from the wireless communication node; or successfully descramble the Msg.4 using the TC-RNTI_offset in combination with the TC-RNTI; or An indication in the Msg.4 is received from the wireless communication node, the indication verifying that the TC-RNTI_offset combined with the TC-RNTI is used as the C-RNTI of the wireless communication device.

14. The method according to claim 13, wherein: The wireless communication node sends a respective Msg. 4 to each of the plurality of wireless communication devices, and the plurality of wireless communication devices send respective Msg. 3 to the wireless communication node.

15. A method comprising: The wireless communication node sends a RAR to a wireless communication device, the RAR including an indication of a maximum number of repetitions repNum of the RAR of at least the wireless communication device, The wireless communication device uses the repNum to determine the time domain position of the transmission resource, at which the RAR transmission Msg.3 will be responded.

16. A non-transitory computer-readable medium storing instructions, which, when executed by at least one processor, cause the at least one processor to perform the method of any one of claims 1 to 15.

17. An apparatus comprising: At least one processor, wherein the at least one processor is configured to implement the method as claimed in any one of claims 1 to 15.

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