Systems and methods for extending communication coverage in non-terrestrial based networks (NTNs)

Abstract

A system and method for communication coverage extension in a non-terrestrial based network (NTN) is presented. A wireless communication device (e.g., a UE) may receive a random access response (RAR) transmission from a wireless communication node (e.g., a BS) that includes an indication indicating at least a maximum repetition number (repNum) of the RAR transmission for the wireless communication device. The wireless communication device can use the repNum to determine a time-domain location of a transmission resource on which a Msg.3 transmission should be transmitted in response to the RAR transmission.

Description

[Technical Field]

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

[0002] The 3rd Generation Partnership Project (3GPP®), a standards organization, is currently in the process of specifying not only a new radio interface called 5G New Radio (5G NR), but also the Next Generation Packet Core Network (NG-CN or NGC). 5G NR will have three main components: the 5G Access Network (5G-AN), the 5G Core Network (5GC), and the User Equipment (UE). To facilitate the enablement of different data services and requirements, the elements of the 5GC, also called network functions, have been simplified; some of them are software-based and some are hardware-based, so they can be adapted as needed. Summary of the Invention [Means for solving the problem]

[0003] The exemplary embodiments disclosed herein are directed to solving problems associated with one or more of the problems presented in the prior art, as well as providing additional features that will be readily apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. In accordance with various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. It will be understood, however, that these embodiments are presented by way of example, and not limitation, and that various modifications to the disclosed embodiments can be made while remaining within the scope of the present disclosure, as will be apparent to those skilled in the art upon reading 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., a UE) can receive / obtain / acquire from a wireless communication node (e.g., a base station (BS), a gNB, and / or a non-terrestrial device) a random access response (RAR) transmission that includes an indication indicating at least a maximum repetition number (repNum) of the RAR transmission for the wireless communication device. The wireless communication device can use the repNum to determine a time-domain location of a transmission resource on which a Msg.3 transmission should 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 should receive multiple RAR transmissions. In some implementations, repNum may have a value that is the same as a maximum repetition number configured or specified 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 location, the wireless communication device can determine an offset using repNum. The wireless communication device can determine the time-domain location by adding an offset to the location of the first or earliest Random Access Response (RAR) window of an RAR transmission.

[0007] In some implementations, a 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 may determine the offset using repNum, requiredRepNum_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). The wireless communication device may determine an offset using repNum or requiredRepNum_UE and the length of the RAR window when repNum matches (or is equal to) requiredRepNum_UE.

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

[0010] In some implementations, a wireless communication device may send a Msg. 3 transmission to a wireless communication node. The Msg. 3 may include an indication of an offset (TC-RNTI_offset) to a Temporary Cell Radio Network Temporary Identifier (TC-RNTI), where TC-RNTI_offset is unique / specific to the wireless communication device. In some implementations, the wireless communication device may determine the number of repetitions required by the wireless communication device (requiredRepNum_UE). The TC-RNTI_offset may have the same value as the value of requiredRepNum_UE or is a function of the value of requiredRepNum_UE.

[0011] In some implementations, the wireless communications node may scramble (e.g., encode or encrypt) the contents of the Msg.4 transmission using the TC-RNTI combined with the TC-RNTI_offset. In some implementations, the wireless communications device may determine to adopt the TC-RNTI combined with the TC-RNTI_offset as a Cell Radio Network Temporary Identifier (C-RNTI) of the wireless communications device in response to receiving the Mg.4 transmission from the wireless communications node, or successfully descrambling (e.g., decoding or decrypting) the Msg.4 transmission using the TC-RNTI combined with the TC-RNTI_offset, or receiving an indication in the Mg.4 transmission from the wireless communications node authorizing the adoption of the TC-RNTI combined with the TC-RNTI_offset as the C-RNTI of the wireless communications device.

[0012] In some implementations, the wireless communication device may send a respective Msg. 4 transmission to each of a plurality of wireless communication devices that sent a respective Msg. 3 transmission 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 to at least one wireless communication device an RAR transmission including an indication indicating a maximum repetition number (repNum) of the RAR transmission for the wireless communication device. The wireless communication device may use the repNum to determine a time-domain location of a transmission resource on which a Msg.3 transmission should be transmitted in response to the RAR transmission. [Brief explanation of the drawings]

[0014] Various exemplary embodiments of the present solution are described in detail below with reference to the following figures or drawings. The drawings are provided for illustrative purposes only and merely depict exemplary embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be considered to limit 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.

[0015] [Figure 1] 1 illustrates an example of a cellular communication network in which the techniques disclosed herein may be implemented according to embodiments of the present disclosure.

[0016] [Figure 2] 1 illustrates a block diagram of an example base station and a user equipment device according to some embodiments of the present disclosure.

[0017] [Figure 3] 1 illustrates an example of a non-terrestrial network (NTN) implementation according to some embodiments of the present disclosure.

[0018] [Figure 4] 1 illustrates an example of an access delay in communication between a UE and a BS according to some embodiments of the present disclosure.

[0019] [Figure 5] 1 illustrates an example implementation of one or more UEs sending Msg. 3 to a BS and one of the UEs receiving a response from the BS according to some embodiments of the present disclosure.

[0020] [Figure 6] 1 illustrates 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.

[0021] [Figure 7] 1 illustrates a flow diagram of an example method for communication coverage extension in an NTN according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022] (1. Mobile Communication Technology and Environment) 1 illustrates an example wireless communication network and / or system 100 in which the techniques disclosed herein according to embodiments of the present disclosure may be implemented. 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 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 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 that overlap a geographic region 101. In FIG. 1, the BS 102 and the UE 104 are contained within the respective geographic boundaries of the cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating in its assigned bandwidth to provide adequate wireless communication coverage to intended users.

[0023] For example, the BS 102 may operate at an assigned channel transmission bandwidth to provide adequate communication coverage to the UE 104. The BS 102 and the UE 104 may communicate via a downlink radio frame 118 and an uplink radio frame 124, respectively. Each radio frame 118 / 124 may be further divided into subframes 120 / 127, which may include data symbols 122 / 128. In this disclosure, the BS 102 and the UE 104 are generally described herein as non-limiting examples of “communication nodes” capable of implementing the methods disclosed herein. Such communication nodes may be capable of wireless and / or wired communication in accordance with various embodiments of the present solution.

[0024] 2 illustrates a block diagram of an exemplary wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM / OFDMA signals) in accordance with some embodiments of the present solution. System 200 may include components and elements configured to support known or conventional operational features that need not be described in detail herein. In one exemplary embodiment, system 200 may be used to communicate (e.g., transmit and receive) data symbols in a wireless communication environment, such as wireless communication environment 100 of FIG. 1, as previously described.

[0025] The system 200 generally includes a base station 202 (hereinafter "BS 202") and a user equipment device 204 (hereinafter "UE 204"). The 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 and interconnected as needed via a data communication bus 220. The 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 and interconnected as needed via a data communication bus 240. The BS 202 communicates with the UE 204 over a communication channel 250, which can be any wireless channel or other medium suitable for the transmission of data as described herein.

[0026] As will be appreciated by those skilled in the art, system 200 may further include any number of modules other than those shown in FIG. 2 . Those skilled in the art will appreciate that the various exemplary 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. To clearly illustrate this compatibility and adaptability of hardware, firmware, and software, the various exemplary components, blocks, modules, circuits, and steps have been described generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software may depend on the particular application and design constraints imposed on the overall system. Those familiar with the concepts described herein may implement such functionality in a manner suitable for each particular application, but such implementation should not be construed as limiting the scope of the present disclosure.

[0027] According to some embodiments, the UE transceiver 230 may be referred to herein as an “uplink” transceiver 230 that includes a radio frequency (RF) transmitter and an RF receiver, each with circuitry coupled to an antenna 232. Alternatively, a duplexing switch (not shown) may 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 also be referred to herein as a “downlink” transceiver 210 that includes an RF transmitter and an RF receiver, each with circuitry coupled to an antenna 212. Alternatively, a downlink duplexing switch may couple the downlink transmitter or receiver to the downlink antenna 212 in a time-duplexed manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that the downlink transmitter is coupled to the downlink antenna 212 while the uplink receiver circuitry is coupled to the uplink antenna 232 for reception of transmissions over the wireless transmission link 250. Conversely, the operation of the two transceivers 210 and 230 may be coordinated in time such that the uplink transmitter is coupled to the uplink antenna 232 at the same time that the downlink receiver is coupled to the downlink antenna 212 for reception of transmissions over the wireless transmission link 250. In some embodiments, there is close time synchronization with minimal guard times between changes in duplex direction.

[0028] The UE transceiver 230 and the base station transceiver 210 are configured to communicate over a wireless data communication link 250 and cooperate with appropriately configured RF antenna arrangements 212 / 232 capable of supporting a particular wireless communication protocol and modulation scheme. In some exemplary 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 will be understood that the present disclosure is not necessarily limited in application to a particular standard and associated protocol. Rather, the UE transceiver 230 and the base station transceiver 210 may be configured to support alternative or additional wireless data communication protocols, including future standards or variants thereof.

[0029] According to various embodiments, the BS 202 may be, for example, an evolved node B (eNB), a serving eNB, a target eNB, a femto station, or a pico station. In some embodiments, the UE 204 may be embodied in various types of user devices, such as a mobile phone, a smartphone, a personal digital assistant (PDA), a tablet, a laptop computer, a wearable computing device, etc. The processor modules 214 and 236 may be implemented or realized using a general-purpose processor, an associative 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 designed to perform the functions described herein. Thus, a processor may be realized as a microprocessor, a controller, a microcontroller, a state machine, etc. A processor may also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a digital signal processor core, or any other such configuration.

[0030] Furthermore, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, firmware, a software module executed by processor modules 214 and 236, respectively, or any practical combination thereof. Memory modules 216 and 234 may be realized 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 can read information from and write information to memory modules 216 and 234, respectively. Memory modules 216 and 234 may be integrated into respective processor modules 210 and 230. In some embodiments, memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during execution of instructions to be executed by processor modules 210 and 230, respectively. Memory modules 216 and 234 may also each include non-volatile memory for storing instructions executed by processor modules 210 and 230, respectively.

[0031] The network communications module 218 generally represents the hardware, software, firmware, processing logic, and / or other components of the base station 202 that enable bidirectional communications 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 communications module 218 may be configured to support Internet or WiMAX traffic. In a typical deployment, without limitation, the network communications module 218 provides an 802.3 Ethernet interface to enable the base station transceiver 210 to communicate with conventional Ethernet-based computer networks. In this embodiment, the network communications module 218 may 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 conjugations thereof refer to devices, components, circuits, structures, machines, signals, etc. that are physically configured, programmed, formatted, and / or arranged to perform the specified operation or function.

[0032] The Open Systems Interconnection (OSI) model (referred to herein as the "Open Systems Interconnection Model") is a conceptual and logical layout that defines network communications used by open systems (e.g., wireless communication devices, wireless communication nodes) to interconnect and communicate with other systems. The model is divided into seven subcomponents or layers, each of which represents a conceptual collection of services provided to its upper and lower layers. The OSI model also defines logical networks and effectively describes computer packet transfers through the use of different layer protocols. The OSI model may also be referred to as the seven-layer OSI model or seven-layer model. In some embodiments, Layer 1 may be the physical layer. In some embodiments, Layer 2 may be the medium access control (MAC) layer. In some embodiments, Layer 3 may be the radio link control (RLC) layer. In some embodiments, Layer 4 may be the packet data convergence protocol (PDCP) layer. In some embodiments, Layer 5 may be the radio resource control (RRC) layer. In some embodiments, layer 6 may be a non-access stratum (NAS) layer or an Internet Protocol (IP) layer, and layer 7 is another layer.

[0033] To enable those skilled in the art to make and use the present solution, various exemplary embodiments of the present solution are described below with reference to the accompanying drawings. As will be apparent to those skilled in the art, 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. Thus, the present solution is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, any specific order or hierarchy of steps in the methods disclosed herein is merely an example approach. Based on design preferences, the specific order or hierarchy of steps in a disclosed method or process can be rearranged while remaining within the scope of the present solution. Thus, those skilled in the art will appreciate that the methods and techniques disclosed herein present various steps or operations in a sample order, and the present solution is not limited to the specific order or hierarchy presented, unless otherwise specified.

[0034] 2. SYSTEMS AND METHODS FOR EXTENDING COMMUNICATION COVERAGE IN NTN In a non-terrestrial network (NTN), the UE 104 acquires / obtains its position / location via a global navigation satellite system (GNSS). Individual UEs 104 are configured with different hardware and / or software components, which may provide various capabilities in supporting communication with the BS 102 and / or non-terrestrial components (e.g., satellites). Based on the capabilities of an individual UE 104, the UE 104 may support a relatively high communication coverage zone (e.g., longer distance) or a relatively low zone (e.g., shorter distance). Some UEs 104 (e.g., with relatively low capabilities) may experience communication coverage issues, such as packet drops, network interference, etc., due to the distance between the UE 104 and at least one of the satellites or the BS 102 being greater than its optimal communication coverage distance. To address / solve potential communication coverage issues in a system, the systems and methods of the technical solutions discussed herein may utilize message repetition to improve communication coverage performance in communications between the UE 104 and the BS 102 (and / or satellites). Furthermore, in some systems (e.g., terrestrial network systems), repetition of random access procedures including a physical downlink control channel (PDCCH) may not be supported for random access transmissions. Therefore, the system and method of the technical solution may provide features or operations discussed herein to support using random access response (RAR) (e.g., including a PDCCH) repetition in random access transmissions to extend / enhance network communication coverage for UEs 104 in NTNs.

[0035] 3 illustrates an example of a transparent NTN structure according to some embodiments of the present disclosure. 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, BS 102, BS 202, 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. To improve / extend communication coverage performance for the UE 104 in an NTN, the systems and methods described herein may enable periodic repetition or multiple repeated transmissions of the RAR (e.g., PDCCH).

[0036] In various configurations for improving communication coverage extension, the systems and methods may, for example, additionally or alternatively, extend a random access response (RAR) window (e.g., the duration for receiving a response from the BS 102) for Msg. 2 (e.g., sometimes referred to as RAR) to allow for transmission repetitions. For example, to extend the RAR window, the network (e.g., the BS 102, a gNB, a satellite, etc.) may indicate / transmit / provide the number of RAR repetitions to the UE 104. The UE 104 may determine / calculate one or more extended RAR windows according to the product of the original (or currently configured) RAR window and the number of RAR repetitions (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 the UE 104 the number of RAR repetitions and the period / cycle / duration between each PDCCH repetition. The UE 104 may extend the RAR window by an offset. The offset may be, for example, the product of the number of repetitions and the repetition period.

[0037] UE104 can be positioned at a certain elevation angle (e.g., distance and / or direction) with respect to the satellite and / or BS102. Based on the locations of UE104, the satellite, and / or BS102, UE104 can experience different path losses, packet drops, interference, and / or other signal propagation errors. Thus, it may be desirable to repeat a certain transmission to UE104 (e.g., a signal or communication) to extend the communication range. Due to the different capabilities (e.g., channel environment) supported by individual UE104, some UE104 may desire or expect more transmission repetitions or fewer transmission repetitions to reduce performance loss. In some cases, some UE104 with relatively high capabilities may not desire repeated transmissions and may expect a single transmission. Thus, different UE104 can be configured with different repetition configurations (e.g., repNum corresponding to the maximum number of repetitions).

[0038] When individual UE104 have different repetition configurations (e.g., for UE1 and UE2, repNum_UE1 < repNum_UE2), when multiple UE104 transmit / send / communicate / signaling the same random access preamble sequence with the same preamble index on the same time-frequency resource to BS102 simultaneously, BS102 can detect different peaks / signals (e.g., correlation of the random access sequence by BS102 or the satellite or other operations), but may not be able to distinguish different peaks as random access requests from one UE104. For example, depending on the distance between UE104 and BS102 or the satellite, the position of the peak obtained by BS102 or the satellite may have a certain (different) shift. Thus, for BS102 to accurately / distinguish clearly the UE104 transmitting the random access request, UE104 can use different random access sequences to initiate random access. For the purpose of providing examples herein, 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 within the same cell.

[0039] 4, an example of access delay in communication between UE 104 and BS 102 is depicted. In the aforementioned situation, if the number of repetitions configured by the network is repNum_UE1 (e.g., a predetermined number of repetitions similar to UE1's maximum repetitions) and UE2 expects a larger number of repetitions compared to UE1 (e.g., repNum_UE2>repNum_UE1), UE2 may fail to decode the RAR (e.g., Msg.2) from BS 102 (e.g., due to a lower-than-desired number of repetitions), causing access failure for UE2. Therefore, by configuring a relatively large number of repetitions, premature access failure of UE2 (or other UEs 104 with similar or lower capabilities) can be mitigated or avoided. For example, when the number of repetitions is configured as repNum_UE2, UE1 and UE2 are based on contention-based random access. However, because some UEs 104 (e.g., UE1) may be able to meet the communication coverage criteria with fewer iterations (e.g., fewer transmissions from the BS 102) compared to the number of iterations (e.g., repNum_UE2) configured by the BS 102, the access delay at the certain UEs 104 may be increased, for example, as shown in Figure 4. The system and method of the technical solution may perform the features or operations described herein to extend the communication coverage for accessing the network (e.g., via transmission repetitions) while minimizing or avoiding access delay at individual UEs 104 (e.g., UEs 104 with relatively higher capabilities and / or lower repNum compared to the repNum configured by the network).

[0040] In various implementations, the UE 104 may measure a synchronization signal block (SSB) or one or more other signals transmitted / provided / transmitted by a network (e.g., BS 102 and / or satellite). The UE 104 may utilize the signal measurements to calculate / calculate or determine a number of repetitions that meet a desired communication coverage (e.g., a communication coverage requirement or criterion). The calculated number of repetitions that meets the communication coverage may be named / denoted / referred to as “requireRepNum_UEx,” where “UEx” may represent the respective UE 104 that performs the calculation, e.g., UE1, UE2, etc. The following relevant definitions may be provided for UEs 104 with different communication coverage requirements (e.g., a greater or lesser number of repetitions): 1) The desired / required number of repetitions of PDCCH for UE1 may be referred to as "requireRepNum_UE1." The required number of repetitions of PDCCH for UE2 may be referred to as "requireRepNum_UE2." 2) The uplink (UL) granted time-frequency resources indicated / signaled in the first RAR (e.g., Msg.2) received in the initial RAR window (w1) may be the initial resources. 3) The maximum repetition number may be configured or predefined by at least one of SIB signaling, RRC signaling, and / or MAC signaling. The maximum repetition number may be used by the UE 104 to avoid having a persistent state of the UE 104 detecting or monitoring the RAR. In response to detecting a number of received transmissions corresponding to requireRepNum_UEx (e.g., a required number of repetitions configured by the network), the UE 104 may merge / combine (across repeated transmissions of the RAR) and decode the RAR. In some implementations, the UE 104 may merge and decode the RAR in response to receiving a number of transmissions corresponding to the maximum repetition number configured for the UE 104. In some cases, if decoding of the RAR fails, such as to avoid the UE 104 being in a persistent state detecting the RAR (in an attempt to successfully decode the RAR), the UE 104 may declare / indicate / indicate that random access has failed and / or that random access has been restarted / restarted.

[0041] In a situation where multiple UEs 104 (e.g., two UEs 104 provided herein) with different communication coverage requirements (e.g., based on the capabilities of each individual UE 104) simultaneously transmit / transmit / signal the same random access preamble sequence to a network (e.g., a BS 102 and / or a satellite) on the same time-frequency resource, the network may repeatedly transmit the same RAR to the UEs 104 to avoid / minimize potential communication coverage issues.

[0042] (Example Implementation 1) In various configurations, the UE 104 may receive a Msg. 2 transmission or a random access response (RAR) transmission from the BS 102. In this specification, the terms Msg. 2 transmission and RAR transmission may be applied and / or used interchangeably. The RAR transmission may include a bit field (e.g., an indication) indicating a maximum number of repetitions (repNum) of the RAR transmission to transmit to the UE 104. The RAR (e.g., a bit field of the RAR including RepNum) may be used to indicate a UL granted time-frequency resource offset (e.g., an implicit indication). For example, the RAR transmission may include a two-bit field (e.g., an indication may be in the two-bit field) to indicate a maximum number of repetitions at the UE 104, and two bits (e.g., represented as “xx”) may indicate that the UE 104 expects to receive multiple RAR transmissions.

[0043] In various implementations, the value of repNum can be the same as a configured or predefined maximum repetition number via at least one of synchronization signal block (SIB) signaling, radio resource control (RRC) signaling, and / or medium access control control element (MAC CE) signaling from the BS 102 and / or satellite. For example, the repNum indicated / provided / sent via an RAR transmission may correspond to a configured maximum repetition number (e.g., previously / in the past transmitted by the BS via RRC or other signaling and / or stored by the UE 104).

[0044] In some implementations, if repNum differs from a predefined maximum repetition number, the UE 104 may decide to use one of the repNum recently received via RAR transmission or a predefined maximum repetition number previously received from the BS 102, for example, according to the configuration of the UE 104. In some configurations, a predefined / configured maximum repetition number may not exist or may not be signaled / indicated to the UE 104 (e.g., not provided by the BS 102 via at least one of the signalings). In such cases, the condition that repNum is equal to the predefined / configured maximum repetition number may not apply.

[0045] The transmission resource corresponding to Msg.3 may include an indication of a resource offset. For UE1 and UE2 (among other UEs 104) with different communication coverage requirements, requireRepNum_UE1 may be configured for UE1, requireRepNum_UE2 may be configured for UE2, and a maximum repetition number (repNum) may be configured / provided in the RAR. In response to UE1 receiving at least one RAR transmission (e.g., two repetitions for UE1 E2 in this example) from BS 102 (e.g., a gNB or wireless communication node), UE1 may transmit / provide Msg.3 to BS 102 on time-frequency resources according to an offset of (requireRepNum_UE1-1)×RARWindowLength corresponding to the UL granted time-frequency resource location it receives in the first RAR window (e.g., after a duration calculated by: In response to UE2 receiving at least one RAR transmission (e.g., four repetitions at UE2 in this example) from BS 102, UE2 may transmit Msg.3 to BS 102 on time-frequency resources according to an offset of (requireRepNum_UE2-1) x RARWindowLength. RARWindowLength (e.g., the length / duration of the RAR window) may be provided to UE 104 by the network via RRC signaling, SIB signaling, among other types of signaling.

[0046] According to the above equation, the UE 104 can determine an offset in the time-domain location (e.g., by adding the offset and the location of the earliest RAR window of the RAR transmission) using at least one of repNum, requiredRepNum_UEx, and / or the RAR window length, among other variables related to the time-domain location for the transmission of Msg.3. In some cases, repNum can be requireRepNum_UEx for each UE 104 receiving the RAR transmission. If repNum=requireRepNum_UEx, each UE 104 (e.g., UEx) can transmit Msg.3 on time-frequency resources according to an offset of ([repNum or requireRepNumUEx]-1)×RARWindowLength, which corresponds to the UL granted time-frequency resource location it receives in the first RAR window. In this case, the UE 104 can determine the offset in time domain location using repNum or requiredRepNum_UEx and, for example, the length of the RAR window where repNum matches (or is equal to) requiredRepNum_UEx.

[0047] 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 adopts / can 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 were to respond to each of these multiple UEs instead). For example, as in the example of FIG. 5, the BS 102 may respond (e.g., transmit a Msg.4 transmission) to the Msg.3 transmission of one of the UEs 104 (e.g., UE1 in this example).

[0048] 5, an implementation is depicted in which UEs 104 (e.g., UE1 and UE2) transmit Msg.3 to BS 102, followed by one of the UEs 104 receiving a response (e.g., Msg.4) from BS 102 and / or a satellite. As shown, UE1 may have / determine a requireRepNum_UE1 of two (e.g., requireRepNum_UE1=2) transmissions to satisfy its communication coverage requirement, and UE2 may have / determine a requireRepNum_UE2 of four (e.g., requireRepNum_UE1=4) transmissions to satisfy its communication coverage requirement. A bit field in the RAR indicating the maximum number of repetitions for UE 104 may be repNum=4.

[0049] In this example, UE1 can transmit Mg.3 on time-frequency resources with an offset of (2-1) x RARWindowLength corresponding to the UL granted time-frequency resource location it receives in the first RAR window, e.g., simply using the formula (requireRepNum_UEx-1) x RARWindowLength to represent the offset. Additionally, UE2 can transmit Mg.3 on time-frequency resources with an offset of (4-1) x RARWindowLength corresponding to the UL granted time-frequency resource location it receives in the first RAR window, e.g., since repNum = requireRepNumUEx, using the formula ([repNum or requireRepNumUEx]-1) x RARWindowLength to represent the offset. As shown in this example, BS 102 can send a response (e.g., a Mg.4 transmission) to only one of UEs 104 that each sent a Mg.3 transmission to BS 102. For example, given the RepNum configuration of BS102 in the RAR message, BS102 may perform blind detection in response to receiving Msg.3 from UE104 to detect Msg.3 transmitted from UE104 with different communication coverage requirements (e.g., different times).

[0050] In some implementations, the UE 104 may detect that the number of RAR transmissions exceeds a predefined maximum repetition number (repNum) (e.g., the number of Msg.2 detection attempt failures exceeds repNum). In response to the detection / failure, the UE 104 may determine that random access has failed. The UE 104 may retry the random access procedure to access the network following a prior random access failure.

[0051] (Example Implementation 2) In various configurations, a bit field included in the RAR can indicate / provide a maximum number of repetitions (repNum) for the UE 104. The bit field can be used to at least implicitly indicate a UL granted time-frequency resource offset (e.g., w1, relative to the first RAR window in Msg.2). Based on the indication from the bit field, the bit field can enable / authorize the BS 102 to perform a Mg.4 transmission in response to receiving Mg.3 from different UEs 104 configured with multiple RAR repeat transmission responses. The Msg.3 transmission can include a bit field (e.g., an indication) indicating a value or offset of "TC-RNTI_offset" specific / unique to the UE 104 that sent the Msg.3 transmission. The offset (e.g., TC-RNTI_offset) indicated by the bit field in the Msg.3 transmission can be related to (e.g., is a function of) the required number of repetitions (requireRepNum_UEx). In some cases, TC-RNTI_offset may contain the same value as the required number of repetitions (e.g., requireRepNum_UEx). The BS 102 may then scramble (e.g., encode or encrypt) the Msg.4 (e.g., the content of the Msg.4 transmission) using a combination of TC-RNTI and TC-RNTI_offset, e.g., TC-RNTI+TC-RNTI_offset. In this case, the UE 104 may descramble (e.g., decode or decrypt) the Msg.4 transmission using the same combination of TC-RNTI+TC-RNTI_offset to confirm / authenticate / complete / verify the upgrade / extension / update to "TC-RNTI+TC-RNTI_offset" as the CRNTI or identifier of the UE 104.

[0052] In some implementations, the Msg.4 transmission may include a bit (e.g., within a bit field) to confirm / authenticate / indicate the upgrade to "TC-RNTI+TC-RNTI_offset." For example, the bit or bit field may include a "1" (or a "0," depending on the transmission configuration) indicating that the upgrade to "TC-RNTI+TC-RNTI_offset" is confirmed, or a different value indicating that the upgrade was rejected or not confirmed.

[0053] For example, the TC-RNTI_offset may be sent / provided / indicated in a Msg.3 transmission. A confirmation message may be sent implicitly or explicitly in a corresponding Msg.4 transmission (in response to the Msg.3 transmission). Techniques or operations for confirming that the UE 104 can update to the TC-RNTI with the offset may include at least one of the following: i) When the UE 104 (eg, UEx) receives a Msg. 3 reply / response (eg, Msg. 4 transmission) from the BS 102, it can determine that it can update the TC-RNTI with the offset to TC-RNTI. ii) If the UE 104 can successfully descramble Msg.4 using "TC-RNTI+TC-RNTI_offset", then the UE 104 can confirm or establish "TC-RNTI+TC-RNTI_offset" as its C-RNTI. iii) If the UE 104 is able to receive Msg. 4 from the BS 102 with a 1-bit indicator indicating confirmation (e.g., instead of or not a failure or rejection indication), the UE 104 can confirm "TC-RNTI+TC-RNTI_offset" as its C-RNTI.

[0054] 6, an example of an implementation is depicted in which the UE 104 transmits Msg.3 to the BS 102 and receives a response from the BS 102, respectively. In various implementations, a two-bit field for the maximum repetition number (repNum) can be configured or defined, and two bits (“xx”) can indicate that the UE 104 is expected to receive multiple RAR transmissions. The transmission resource (e.g., time-domain location) in Msg.3 can be based on the resource offset associated with the bit field indicator RAR transmission. For UE1 and UE2 with different communication coverage requirements, requireRepNum_UE1 can be determined for UE1, requireRepNum_UE2 can be determined for UE2, and the maximum repetition number (repNum) can be configured in the RARs received by UE1 and UE2.

[0055] After receiving the RAR transmission, UE1 may transmit Mg.3 on time-frequency resources with an offset of (requireRepNum_UE1-1) × RARWindowLength corresponding to the UL granted time-frequency resource locations it receives in the first RAR window (e.g., after a duration calculated by): UE2 may transmit Mg.3 on time-frequency resources at (requireRepNum_UE2-1) × RARWindowLength corresponding to the UL granted time-frequency resource locations it receives in the first RAR window (e.g., after a duration calculated by): If repNum=requireRepNum_UEx, then UEx may transmit Mg.3 on time-frequency resources with an offset of ([repNum or requireRepNum_UEx]-1) × RARWindowLength corresponding to the UL granted time-frequency resource locations it receives in the first RAR window. BS 102 may receive Msg. 3 transmissions from UE1 and UE2. BS 102 may send Msg. 4 transmissions to UE1 and UE2, respectively (e.g., at different time domain locations) in response to receiving the Msg. 3 transmissions from different UEs 104. After receiving the Mg. 4 transmissions 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 to, for example, complete a random access process and improve channel capacity or communication coverage.

[0056] FIG. 7 illustrates a flow diagram of an example method 700 for communication coverage extension in an NTN. Method 700 may be implemented using any one or more of the components and devices detailed herein in connection with FIGS. 1-6. Briefly, method 700 may be performed, in some embodiments, by at least one wireless communication device (e.g., a UE or terminal device), at least one wireless communication node (e.g., a BS, a gNB, or access network equipment), at least one satellite, etc. Depending on the embodiment, additional, fewer, or different operations may be performed in method 700. At least one aspect of these operations is directed to a system, a method, an apparatus, or a computer-readable medium.

[0057] At operation 702, a wireless communication node may send / transmit / communicate an RAR transmission to at least one wireless communication device (or multiple wireless communication devices). The RAR transmission may include an indication indicating a maximum repetition number (repNum) of the RAR transmission for at least the wireless communication device, among other wireless communication devices (e.g., for all UEs). At operation 704, the wireless communication device may receive / obtain / acquire the RAR transmission from the wireless communication node.

[0058] 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 indicate that the wireless communication device will receive (e.g., is expected 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 a maximum repetition number, which may be configured or specified via system information block (SIB) signaling, radio resource control (RRC) signaling, and / or medium access control control element (MAC CE) signaling, among other types of signaling.

[0059] At operation 704, the wireless communication device may use at least the repNum to determine a time domain location of a transmission resource where a Msg. 3 transmission should be transmitted in response to the RAR transmission.

[0060] In various configurations, the wireless communication device may determine the time domain location according to an offset (e.g., a resource offset or a time domain offset). For example, the wireless communication device may determine the offset using repNum. In some cases, the value of the offset may correspond to the value of repNum. In some 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 location, for example, by adding the offset to the location of an earliest random access response (RAR) window of an RAR transmission.

[0061] 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. The wireless communication device may determine the offset using requiredRepNum_UE and the length of the RAR window.

[0062] In some implementations, the wireless communication device may determine the number of repetitions required by the wireless communication device (requiredRepNum_UE). 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 for the respective wireless communication device). If repNum=requiredRepNum_UE, the wireless communication device may determine the offset using a technique / function / formula that uses repNum or requiredRepNum_UE and the length of the RAR window.

[0063] In some implementations, the wireless communication device may send the Msg.4 transmission to only one of multiple wireless communication devices that each sent a Msg.3 transmission to the wireless communication node. In some implementations, the wireless communication device may determine failure due to the number of RAR detection attempts exceeding repNum (e.g., the wireless communication device attempted to detect the RAR more than a maximum number of repetitions). In response to the failure due to the number of RAR detection attempts, the wireless communication device may determine that the random access failed.

[0064] In various configurations, the wireless communication device may send a Msg.3 transmission to a wireless communication node. The Msg.3 transmission may include an indication of an offset (TC-RNTI_offset) to a Temporary Cell-Radio Network Temporary Identifier (TC-RNTI). The TC-RNTI_offset may be unique to the wireless communication device, such as being different from the TC-RNTI_offset of other wireless communication devices. In some cases, the wireless communication device may determine a number of repetitions required by the wireless communication device (requiredRepNum_UE). The TC-RNTI_offset may include the same value as the value of requiredRepNum_UE or be a function of the value of requiredRepNum_UE.

[0065] In various implementations, a wireless communication node may use the TC-RNTI combined with the TC-RNTI_offset to scramble the content of the Msg.4 transmission (e.g., according to TC-RNTI+TC-RNTI_offset). In such a case, the wireless communication device may determine whether to adopt / use the TC-RNTI combined with the TC-RNTI_offset as the Cell Radio Network Temporary Identifier (C-RNTI) of the wireless communication device. For example, the wireless communications device may determine to adopt the TC-RNTI combined with TC-RNTI_offset as its C-RNTI (e.g., within the BS's cell) in response to at least one of: i) the wireless communications device (successfully) receiving a Msg.4 transmission from a wireless communications node (e.g., in response to its Msg.3 transmission); ii) the wireless communications device successfully descrambling the Msg.4 transmission using the TC-RNTI combined with TC-RNTI_offset; and / or iii) the wireless communications device receiving an indication in the Mg.4 transmission from the wireless communications node authenticating / confirming / approving the adoption of the TC-RNTI combined with TC-RNTI_offset as the wireless communications device's C-RNTI.

[0066] In some implementations, the wireless communications node may transmit a respective Msg.4 transmission to each of the various wireless communications devices that sent a respective Msg.3 transmission to the wireless communications node, such that each of the wireless communications devices that sent a Msg.3 transmission to the wireless communications node can complete a random access process (and employ a CRNTI that is unique to each of the wireless communications devices).

[0067] While various embodiments of the present solution have been described above, it should be understood that they are presented by way of example only, and not by way of limitation. Similarly, various diagrams may depict example architectures or configurations, which are provided to enable those skilled in the art to understand example features and functionality of the present solution. However, such skilled artisans will appreciate that the present solution is not limited to the illustrated example architectures or configurations, but can be implemented using various alternative architectures and configurations. Furthermore, as will be understood by those skilled in the art, one or more features of one embodiment can also be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any of the example embodiments described above.

[0068] It is also understood that any reference to an element herein using a designation such as "first," "second," etc., generally does not limit the quantity or order of those elements. Rather, these designations 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 imply that only two elements can be used, or that the first element must precede the second element in any way.

[0069] Additionally, those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, and symbols that may be referred to in the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0070] Those skilled in the art will further appreciate that any of the various illustrative logic blocks, modules, processors, means, circuits, methods, and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., digital implementations, analog implementations, or a combination of the two), firmware, various forms of programs or design code incorporating instructions (which may be conveniently referred to herein as “software” or “software modules”), or any combination of these techniques. To clearly illustrate this interchangeability of hardware, firmware, and software, the various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these techniques, depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure.

[0071] Furthermore, those skilled in the art will appreciate that the various example logic blocks, modules, devices, components, and circuits described herein can be implemented in or 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 further include an antenna and / or transceiver for communicating with various components within a network or device. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration for performing the functions described herein.

[0072] If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media, including any medium that can be enabled to transfer a computer program or code from one place to another. A 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 can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0073] As used herein, the term "module" refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, while for purposes of discussion, various modules are described as individual modules, those skilled in the art will appreciate that two or more modules may be combined to form a single module that performs associated functions according to embodiments of the present solution.

[0074] Additionally, memory or other storage, as well as communication components, may be used in embodiments of the solution. It will be understood that, for clarity, the above description describes embodiments of the solution with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements, or domains may be used without detracting from the solution. For example, functionality illustrated as being performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. References to specific functional units therefore do not dictate a strict logical or physical structure or organization, but merely to suitable means for providing the described functionality.

[0075] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, 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. 1. A method, comprising: receiving, by a wireless communication device, a random access response (RAR) transmission from a wireless communication node, the RAR transmission including an indication indicating at least a maximum number of repetitions (repNum) of the RAR transmission for the wireless communication device; determining, by the wireless communication device, a time domain location of a transmission resource on which a Msg. 3 transmission should be transmitted in response to the RAR transmission, using the repNum; A method comprising:

2. The method of claim 1 , wherein the indication is in a two-bit field.

3. The method of claim 1 , wherein the instruction indicates that the wireless communication device should receive multiple RAR transmissions.

4. 2. The method of claim 1, wherein repNum has a value that is the same as a maximum repetition number configured or defined via system information block (SIB) signaling, radio resource control (RRC) signaling, or medium access control control element (MAC CE) signaling.

5. Determining the time domain location includes: determining, by the wireless communication device, an offset using the repNum; determining, by the wireless communication device, the time domain location by adding the offset to an earliest RAR window location of the RAR transmission; and The method of claim 1 , comprising:

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

7. determining, by the wireless communication device, a number of repetitions required by the wireless communication device (requiredRepNum_UE); determining, by the wireless communication device, when the repNum matches the requiredRepNum_UE, the offset using the repNum or the requiredRepNum_UE and a length of an RAR window; The method of claim 5 , comprising:

8. 10. The method of claim 1, wherein the wireless communication node transmits a Msg. 4 transmission to only one of a plurality of wireless communication devices that each transmitted a Msg. 3 transmission to the wireless communication node.

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

10. 10. The method of claim 1, comprising sending, by the wireless communication device to the wireless communication node, a Msg. 3 transmission including an indication of an offset (TC-RNTI_offset) to a Temporary Cell Radio Network Temporary Identifier (TC-RNTI), wherein the TC-RNTI_offset is unique to the wireless communication device.

11. determining, by the wireless communication device, a number of repetitions required by the wireless communication device (requiredRepNum_UE); The method of claim 10, wherein the TC-RNTI_offset has a value that is the same as the value of the requiredRepNum_UE or is a function of the value of the requiredRepNum_UE.

12. 11. The method of claim 10, wherein the wireless communications node scrambles content of a Msg. 4 transmission using the TC-RNTI combined with the TC-RNTI_offset.

13. determining, by the wireless communication device, to adopt the TC-RNTI combined with the TC-RNTI_offset as a Cell Radio Network Temporary Identifier (C-RNTI) of the wireless communication device; The determining step comprises: receiving a Msg. 4 transmission from said wireless communication node; or successfully descrambling a Msg. 4 transmission using the TC-RNTI combined with the TC-RNTI_offset; or receiving, in the Msg. 4 transmission, an indication from the wireless communication node authorizing adoption of the TC-RNTI combined with the TC-RNTI_offset as the C-RNTI of the wireless communication device. The method of claim 12 , wherein the method is responsive to

14. 14. The method of claim 13, wherein the wireless communication node transmits a respective Msg. 4 transmission to each of a plurality of wireless communication devices that transmitted a respective Msg. 3 transmission to the wireless communication node.

15. 1. A method, comprising: transmitting, by the wireless communications node, to a wireless communications device, an RAR transmission including an indication indicating at least a maximum number of repetitions (repNum) of the RAR transmission for said wireless communications device; The wireless communications device uses the repNum to determine a time domain location of a transmission resource where a Msg. 3 transmission should be transmitted in response to the RAR transmission.

16. 16. A non-transitory computer-readable medium storing instructions that, 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. 16. An apparatus comprising at least one processor configured to perform the method of any one of claims 1 to 15.

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