Enhancements to synchronization, random access, and HARQ behavior for non-terrestrial networks

Abstract

A user device (UE), a base station, and a method for managing hybrid automatic repeat request (HARQ) feedback for downlink synchronization are provided. The UE includes at least one transceiver configured to receive downlink control information (DCI) on a physical downlink control channel (PDCCH), and at least one processor operably connected to the at least one transceiver. The at least one processor is configured to determine whether hybrid automatic repeat request (HARQ) feedback is disabled based on a first field of the DCI, and if HARQ feedback is disabled, to determine that a second field of the DCI is either a reserved field or a zero-bit-width field based on the format of the DCI.

Description

Technology Field

[0001] The present disclosure relates to a pre-5G or 5G communication system provided to support a higher data rate than a Beyond 4th-Generation communication system, such as Long-Term Evolution (LTE). In particular, embodiments of the present disclosure relate to a non-terrestrial network. In particular, embodiments of the present disclosure relate to downlink synchronization, management of HARQ transmission, and an enhanced PRACH preamble format. Background Technology

[0002] Wireless communication has been one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services has surpassed 5 billion and continues to grow rapidly. The demand for wireless data traffic is increasing rapidly due to the rising popularity among consumers and enterprises of smartphones and other mobile data devices, such as tablets, "notepad" computers, netbooks, eBook readers, and mechanical devices. To meet the high growth of mobile data traffic and support new applications and deployments, improving wireless interface efficiency and coverage is of paramount importance.

[0003] Efforts are being made to develop improved 5G or pre-5G communication systems to meet the increasing demand for wireless data traffic following the deployment of 4G communication systems. For this reason, 5G or pre-5G communication systems are also referred to as "Beyond 4G Network" communication systems or "Post-LTE System" communication systems.

[0004] To achieve high data transmission rates, 5G communication systems are considered to be implemented in the mmWave band (e.g., the 60 GHz band). To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO (Multiple-Input Multiple-Output), FD-MIMO (Full Dimensional MIMO), array antenna, analog beamforming, and large-scale antenna technologies are being discussed in 5G communication systems.

[0005] In addition, to improve the network of the system, technologies such as advanced small cell, cloud Radio Access Network (cloud RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Point (CoMP), and reception-end interference cancellation are being developed in 5G communication systems. Advanced Coding Modulation (ACM) methods such as Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), as well as advanced access technologies such as Filter Bank Multi Carrier (FBMC), Non-Orthogonal Multiple Access (NOMA), and Spare Code Multiple Access (SCMA), are being developed in 5G communication systems.

[0006] The Internet, a human-centered connectivity network where humans generate and consume information, is now evolving into the Internet of Things (IoT), where distributed entities such as objects exchange and process information without human intervention. The Internet of Everything (IoE) technology, which combines IoT technology with Big Data processing technology through connections with cloud servers, is emerging. To implement IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required; consequently, technologies such as sensor networks, Machine-to-Machine (M2M), and Machine-Type Communication (MTC) are currently being researched to facilitate connections between objects. In an IoT environment, intelligent Internet Technology (IT) services can be provided to create new value for human life by collecting and analyzing data generated from connected objects. Through the convergence and integration of existing Information Technology (IT) technologies with various industries, IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0007] Accordingly, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, Machine-Type Communication (MTC), and Machine-to-Machine (M2M) are being implemented using 5G communication techniques such as beamforming, MIMO, and array antennas. The application of Cloud Radio Access Network (Cloud RAN) as the big data processing technology described earlier can also be considered an example of the convergence between 5G technology and IoT technology. The problem to be solved

[0008] Embodiments of the present disclosure include a method for managing user equipment (UE), a base station (BS), and hybrid automatic repeat request transmission in a wireless communication system. means of solving the problem

[0009] One embodiment relates to a UE comprising at least one transceiver configured to receive downlink control information (DCI) from a physical downlink control channel (PDCCH), and at least one processor operably connected to at least one transceiver. The at least one processor determines whether hybrid automatic repeat request (HARQ) feedback is disabled based on a first field of the DCI, and if HARQ feedback is disabled, determines that a second field of the DCI becomes either a reserved field or a zero-bit-width field based on the format of the DCI.

[0010] Another embodiment relates to a BS comprising a transceiver configured to transmit downlink control information (DCI) on a physical downlink control channel (PDCCH). The BS also comprises a processor operably connected to the transceiver, the processor being configured to determine whether hybrid automatic repeat request (HARQ) feedback is disabled. The processor is also configured to generate a DCI having a first field indicating whether HARQ feedback is disabled. The DCI includes a second field which, if the first field indicates that HARQ feedback is disabled, may be determined to be either a reserved field or a zero-bit-width field based on the format of the DCI.

[0011] Another embodiment relates to a method comprising the steps of: receiving downlink control information (DCI) from a physical downlink control channel (PDCCH); determining whether hybrid automatic repeat request (HARQ) feedback is disabled based on a first field of the DCI; and, if HARQ feedback is disabled, determining whether a second field of the DCI becomes either a reserved field or a zero-bit width field based on the format of the DCI.

[0012] Other technical features may be readily apparent to a person skilled in the art from the following drawings, description, and claims.

[0013] Before proceeding with the detailed description below, it may be advantageous to define specific words and phrases used throughout this patent document. The term "couple" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not they are in physical contact with each other. The terms "transmit," "receive," and "communicate," as well as their derivatives, include both direct and indirect communication. The terms "include" and "comprise," as well as their derivatives, mean inclusion without limitation. The term "or" is inclusive and means and / or. The term "associated with" as well as its derivatives mean "include," "included within," "interconnect with," "contain," "be contained within," "connect to or with," "couple to or with," "be communicable with," "cooperate with," "interleave," "juxtapose," "be proximate to," "be bound to or with," "have," "have a property of," "have a relationship to or with," and so on. The term "control unit" means any device, system, or part thereof that controls at least one operation.The above control unit may be implemented in hardware or a combination of hardware and software and / or firmware. Functions associated with any specific control unit may be centralized or distributed locally or remotely. The phrase "at least one of" means that, when used with a list of items, one or more different combinations of the listed items may be used, and only one item may be required within the list. For example, "at least one of A, B, and C" includes any one of the following combinations: A, B, C, A and B, A and C, B and C, and A, B, and C.

[0014] Furthermore, the various functions described below may be implemented or supported by one or more computer programs, each computer program being formed from computer-readable program code and implemented on a computer-readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, associated data, or parts thereof adapted for implementation in appropriate computer-readable program code. The phrase “computer-readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer-readable medium” includes any type of medium accessible by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drives, compact discs (CDs), digital video discs (DVDs), or any other type of memory. "Non-transitory" computer-readable media exclude wired, wireless, optical, or other communication links that transmit transient electrical or other signals. Non-transitory computer-readable media include media in which data can be permanently stored, and media in which data can be stored and subsequently overwritten, such as rewritable optical discs or erasable memory devices.

[0015] Definitions for other specific words and phrases are provided throughout this patent document. A person skilled in the art should understand that, though not in most cases, these definitions apply to the prior and subsequent use of such defined words and phrases. Effects of the invention

[0016] According to one embodiment of the present disclosure, a UE or a base station can efficiently manage hybrid automatic repetitive request transmission. Brief explanation of the drawing

[0017] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken together with the accompanying drawings. FIGS. 1a and 1b illustrate exemplary wireless communication networks according to various embodiments of the present disclosure. FIG. 2 illustrates an exemplary base station (BS) in a wireless communication network according to various embodiments of the present disclosure. FIG. 3 illustrates an exemplary user device (UE) in a wireless communication network according to various embodiments of the present disclosure. FIGS. 4a and FIGS. 4b illustrate exemplary transmission and reception paths according to various embodiments of the present disclosure. FIG. 5 illustrates an exemplary transmitter according to various embodiments of the present disclosure. FIG. 6 illustrates an exemplary receiver according to various embodiments of the present disclosure. FIG. 7 illustrates the SS / PBCH block configuration for NR Rel-15 according to various embodiments of the present disclosure. FIG. 8 illustrates an SS / PBCH block pattern in the time domain for NR Rel-15 according to various embodiments of the present disclosure. FIG. 9 illustrates the SS / PBCH block location within a half frame for NR Rel-15 according to various embodiments of the present disclosure. FIG. 10 illustrates a beam footprint generated by a satellite according to various embodiments of the present disclosure. FIG. 11 illustrates frequency repetition of an SSB according to various embodiments of the present disclosure. FIG. 12 illustrates a PRACH format having a long sequence according to various embodiments of the present disclosure. FIG. 13 illustrates a PRACH format having a short sequence according to various embodiments of the present disclosure. FIGS. 14a and 14b illustrate exemplary PRACH formats according to various embodiments of the present disclosure. FIGS. 15a and 15b illustrate additional exemplary PRACH formats according to various embodiments of the present disclosure. FIG. 16 illustrates additional exemplary PRACH formats according to various embodiments of the present disclosure. FIG. 17 illustrates additional exemplary PRACH formats according to various embodiments of the present disclosure. FIG. 18 illustrates a flowchart of a process for managing HARQ transmission in a wireless network according to various embodiments of the present disclosure. Specific details for implementing the invention

[0018] The drawings included in this specification and the various embodiments used to illustrate the principles of this disclosure are for illustrative purposes only and should not be construed as limiting the scope of this disclosure in any way. Furthermore, a person skilled in the art will understand that the principles of this disclosure may be implemented in any wireless communication system appropriately arranged.

[0019] The following documents are incorporated by reference into this disclosure as fully described herein: 3GPP TS 38.211 v15.5.0 and v15.6.0, "NR; Physical channels and modulation" hereinafter "REF 1"; 3GPP TS 38.212 v15.5.0 and v15.6.0, "NR; Multiplexing and channel coding" hereinafter "REF 2"; 3GPP TS 38.213 v15.5.0 and v15.6.0, "NR; Physical layer procedures for control" hereinafter "REF 3"; 3GPP TS 38.214 v15.5.0 and v15.6.0, "NR; Physical layer procedures for data" hereinafter "REF 4"; 3GPP TS 38.331 v15.5.0 and v15.6.0, "NR; Radio Resource Control (RRC) protocol specification", hereinafter "REF 5". NR (New radio) supports synchronization through synchronization signals transmitted over the downlink. Compared to LTE (Long-Term Evolution), NR supports a wider range of carrier frequencies and more flexible numerology. These concepts are explained in more detail in the discussion of the following Figures 7 through 9. A new aspect of the present disclosure is that in the case of a non-terrestrial network (NTN), there is generally a long delay spread between the transmitter and receiver (e.g., tens to hundreds of ms for different development scenarios), and in some development scenarios, there is a significant Doppler shift due to the high mobility of the satellite. These aspects affect downlink synchronization performance. The present disclosure proposes enhancements to address downlink synchronization issues in NTNs.

[0020] NR Rel-15 also supports multiple physical random access channel (PRACH) preamble formats. Formats 0, 1, 2, and 3 have a sub-carrier spacing (SCS) of 1.25 kHz or 5 kHz for a long preamble sequence length of 839. Formats A1, A2, A3, B1, B2, B3, B4, C0, and C2 have SCSs of 15 kHz, 30 kHz, 60 kHz, and 120 kHz for a short preamble sequence length of 139. An example of a PRACH preamble format with a long sequence is shown in FIG. 12, and an example of a PRACH preamble format with a short sequence is shown in FIG. 13.

[0021] For new types of use cases for NR beyond Rel-15, NTN considers a network or segment of a network that uses RF resources mounted on a satellite or UAS platform, as illustrated in FIG. 1b. For NTN, since the footprint of the transmit beam generated by the satellite is much larger than that of the ground cell in NR Rel-15, the coverage of the PRACH preamble supported in Rel-15 may not be sufficient. Accordingly, the novel aspects of the present disclosure recognize the need for improvements to the PRACH preamble format to support large cell sizes. As discussed in more detail herein, improvements may be in the sequence length used for the PRACH preamble, the SCS supported for the PRACH preamble, and the PRACH preamble configuration. Two sets of PRACH preamble formats are described in the present disclosure. The first set of PRACH preamble formats is based on an SCS scaled at 1.25 kHz, and the second set of PRACH preamble formats is based on an SCS scaled at 15 kHz.

[0022] NR also supports hybrid automatic repeat requests (HARQ) on both the downlink and uplink. More precisely, asynchronous HARQ is supported for both the downlink and uplink, where multiple HARQ processes operate in a random order. To track each HARQ process, both the transmitter and receiver within the HARQ process must know the exact HARQ process number to accurately receive the transmission or retransmission. Meanwhile, unlike LTE, the timing between data transmission and HARQ response is dynamic in NR. Radio resource control (RRC) messages establish a table of possible timing offsets between data transmission and HARQ response, and downlink control information (DCI) further indicates which values ​​in the established table are utilized between a scheduled data transmission and the corresponding HARQ response.

[0023] In the case of NTN, there is generally a significant propagation delay between the transmitter and receiver, and the specific maximum round trip delay (RTD) varies depending on the implementation scenario. Table 7 shows exemplary maximum RTDs for some common NTN scenarios. As can be seen, for geosynchronous equatorial orbit (GEO) satellites, the maximum RTD can exceed 500 ms, and for low-earth orbit (LEO) satellites, the maximum RTD can be as large as 40 ms in extreme cases, both of which are much larger than those considered for ground networks.

[0024] The large propagation delay of NTN causes problems with the efficiency of HARQ, and the significant increase in buffer sizes at both the transmitter and receiver poses a problem for HARQ implementation. Accordingly, the novel aspects of the present disclosure also recognize that it is necessary to disable HARQ for at least some NTN scenarios, and the present disclosure includes details of a method for disabling HARQ and corresponding effects when HARQ is disabled.

[0025] FIG. 1a illustrates an exemplary wireless communication network (100a) according to various embodiments of the present disclosure. The embodiment of the wireless network (100a) illustrated in FIG. 1a is for illustrative purposes only. Other embodiments of the wireless network (100a) may be used without departing from the scope of the present disclosure.

[0026] As illustrated in FIG. 1a, the wireless network (100a) includes a gNB (gNodeB) (101), a gNB (102), and a gNB (103). The gNB (101) communicates with the gNB (102) and the gNB (103). The gNB (101) also communicates with at least one IP network (130), such as the Internet, a proprietary IP (Internet Protocol) network, or another data network.

[0027] The gNB (102) provides wireless broadband access to a network (130) for a first plurality of user devices (UEs) within the coverage area (120) of the gNB (102). The first plurality of UEs include a UE (111) that may be located in a small business (SB); a UE (112) that may be located in an enterprise (E); a UE (113) that may be located in a WiFi hotspot (HS); a UE (114) that may be located in a first residence (R); a UE (115) that may be located in a second residence (R); and a UE (116) that may be a mobile device (M) such as a cell phone, a wireless laptop, a wireless PDA, etc. The gNB (103) provides wireless broadband access to a network (130) for a second plurality of UEs within the coverage area (125) of the gNB (103). The second plurality of UEs includes UE (115) and UE (116).

[0028] Depending on the network type, the term “base station” may refer to any component (or set of components) configured to provide wireless access to a network, such as a transmit point (TP), transmit-receive point (TRP), gNB, macrocell, femtocell, WiFi access point (AP), or other wirelessly enabled device. A base station may provide wireless access according to one or more wireless communication protocols, for example, 5G 3GPP NR (New Radio Interface / Access), LTE (long term evolution), LTE-A (LTE-advanced), High Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. Additionally, depending on the network type, other well-known terms such as "mobile station," "subscriber station," "remote terminal," "wireless terminal," or "user device" may be used instead of "user device" or "UE." For convenience, the terms "user device" and "UE" are used in this patent document to refer to a remote wireless device wirelessly accessing the gNB, whether the UE is a mobile device (such as a mobile phone or smartphone) or is generally considered a stationary device (such as a desktop computer or vending machine).

[0029] The dotted lines show the approximate range of the coverage areas (120 and 125), which are depicted as nearly circular for illustrative and explanatory purposes only. It should be clearly understood that coverage areas associated with a gNB, such as the coverage areas (120 and 125), may have different shapes, including irregular shapes, depending on the configuration of the gNB and changes in the radio environment related to natural and man-made obstructions.

[0030] As described in more detail below, the wireless network (100a) may be a 5G communication system capable of communicating with network components such as a UE (116) to facilitate BS and / or downlink synchronization, management of HARQ transmission and / or implementation of an enhanced PRACH preamble format in a non-terrestrial network.

[0031] FIG. 1a illustrates an example of a wireless network (100a), but various modifications to FIG. 1a may be made. For example, the wireless network (100a) may include any number of gNBs and any number of UEs in any suitable arrangement. Additionally, a gNB (101) may communicate directly with any number of UEs and provide wireless broadband access to the network (130) to these UEs. Similarly, each gNB (102-103) may communicate directly with the network (130) and provide direct wireless broadband access to the network to the UEs. Additionally, the gNBs (101, 102 and / or 103) may provide access to other or additional external networks, such as an external telephone network or other types of data networks.

[0032] FIG. 1b illustrates another exemplary wireless communication network according to various embodiments of the present disclosure. The non-ground network (100b) may be a standalone network or a segment of a network using RF resources mounted on a satellite or unmanned aerial system (UAS) platform.

[0033] NTN (100b) exemplifies a typical scenario of an NTN providing access to a user device (156). NTN (100b) generally includes one or more satellite gateways (151) that connect NTN (100b) to a public data network. NTN (100b) also includes GEO satellites (154) served by one or more satellite gateways (151) deployed across satellite targeted coverage (e.g., regional or even continental coverage). It can be assumed that a UE, such as a UE (156) in a cell, is served by only one satellite gateway. Non-GEO satellites may be served continuously by one or more satellite gateways at a time, and the system ensures service and feeder link continuity between the continuously serving satellite gateways with a time duration sufficient to proceed with mobility anchoring and handover.

[0034] The NTN (100b) may also include a UAS platform. The satellite (154) or UAS platform may implement a transparent or regenerated payload (including on-board processing). A transparent payload includes radio frequency filtering, frequency conversion, and amplification so that the waveform signal repeated by the payload is not altered. A regenerated payload includes radio frequency filtering, frequency conversion, and amplification, as well as demodulation / decoding, switching and / or routing, and coding / modulation, which is virtually identical to having all or part of the base station functions (e.g., gNB) mounted on the satellite (154) or UAS platform.

[0035] A satellite (154) or UAS platform typically generates multiple beams across a given service area defined by a field of view, as illustrated in FIG. 10. The footprint of the beams is typically elliptical. The field of view of the satellite (154) or UAS platform depends on the onboard antenna diagram and the minimum elevation angle.

[0036] The satellite (154) may be connected to one or more satellite gateways (151) by a feeder link or a wireless link (152). The satellite (154) may have a service link or a wireless link (153) with a UE (156). The satellite (154) may also have an optional other inter-satellite link (ISL) (155) to implement a satellite constellation. This will require a replay payload carried on the satellite. The ISL (155) may operate in an RF frequency or optical band.

[0037] As described in more detail below, NTN (100b) can be used to facilitate downlink synchronization, management of HARQ transmission, and / or implementation of an enhanced PRACH preamble format.

[0038] FIG. 2 illustrates an exemplary base station (BS) according to various embodiments of the present disclosure. The embodiment of the gNB (102) shown in FIG. 2 is for illustrative purposes only, and the gNBs (101 and 103) of FIG. 1 may have the same or similar configurations. However, gNBs may have various configurations, and FIG. 2 does not limit the scope of the present disclosure to any specific implementation of a gNB. Additionally, the BS may take the form of a satellite or a UAS platform as described in FIG. 1b.

[0039] As illustrated in FIG. 2, the gNB (102) includes a plurality of antennas (280a-280n), a plurality of RF transceivers (282a-282n), a transmit (TX) processing circuit (284), and a receive (RX) processing circuit (286). The gNB (102) also includes a control unit / processor (288), a memory (290), and a backhaul or network interface (292).

[0040] RF transceivers (282a-282n) receive an incoming RF signal from an antenna (280a-280n), such as a signal transmitted by a UE from a network (100a). The RF transceivers (282a-282n) down-convert the incoming RF signal to generate an IF or baseband signal. The IF or baseband signal is transmitted to an RX processing circuit (286) that generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuit (286) transmits the processed baseband signal to a control unit / processor (288) for further processing.

[0041] The TX processing circuit (284) receives analog or digital data (such as voice data, web data, email, or interactive video game data) from the control unit / processor (288). The TX processing circuit (284) encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver (282a-282n) receives the outgoing processed baseband or IF signal from the TX processing circuit (284) and upconverts the baseband or IF signal into an RF signal transmitted through the antenna (280a-280n).

[0042] The control unit / processor (288) may include one or more processors or other processing devices that control the overall operation of the gNB (102). For example, the control unit / processor (288) may control the reception of a forward channel signal and the transmission of a reverse channel signal by means of an RF transceiver (282a-282n), an RX processing circuit (286), and a TX processing circuit (284) according to well-known principles. The control unit / processor (288) may also support additional functions, such as more advanced wireless communication functions. For example, the control unit / processor (288) may support differently weighted beamforming or directional routing operations to effectively steer outgoing signals from a plurality of antennas (280a-280n) in a desired direction. Any of the various other functions may be supported in the gNB (102) by the control unit / processor (288). In some embodiments, the control unit / processor (288) includes at least one microprocessor or microcontroller.

[0043] The control unit / processor (288) can also execute programs and other processes residing in memory (290), such as the basic OS. The control unit / processor (288) can move data in and out of memory (290) as required by the execution process.

[0044] The control unit / processor (288) is also coupled to a backhaul or network interface (292). The backhaul or network interface (292) enables the gNB (102) to communicate with other devices or systems via a backhaul connection or network. The interface (292) may support communication via any suitable wired or wireless connection. For example, when the gNB (102) is implemented as part of a cellular communication system (such as one that supports 5G, LTE, or LTE-A), the interface (292) enables the gNB (102) to communicate with other gNBs via a wired or wireless backhaul connection. When the gNB (102) is implemented as an access point, the interface (292) enables the gNB (102) to communicate with a larger network (such as the Internet) via a wired or wireless local area network or a wired or wireless connection. The interface (292) includes any suitable structure that supports communication via a wired or wireless connection, such as Ethernet or an RF transceiver.

[0045] The memory (290) is coupled to the control unit / processor (288). Part of the memory (290) may include RAM, and other parts of the memory (290) may include flash memory or other ROM.

[0046] As described in more detail below, BS (102) can transmit information to a UE, such as the UE (116) of FIG. 1, over a network to facilitate downlink synchronization, management of HARQ transmission, and / or implementation of an enhanced PRACH preamble format.

[0047] FIG. 2 illustrates an example of a gNB (102), but various modifications to FIG. 2 may be made. For example, the gNB (102) may include any number of individual components as illustrated in FIG. 2. As a specific example, the access point may include a number of interfaces (292), and the control unit / processor (288) may support a routing function that routes data between different network addresses. As another specific example, although it is illustrated as including a single instance of a TX processing circuit (284) and a single instance of an RX processing circuit (286), the gNB (102) may include multiple instances of each (such as one per RF transceiver). Additionally, the various components of FIG. 2 may be combined, further subdivided, or omitted, and additional components may be added as needed.

[0048] FIG. 3 illustrates an exemplary user device (UE) according to various embodiments of the present disclosure. The embodiment of the UE (116) shown in FIG. 3 is for illustrative purposes only, and the UE (111-115) of FIG. 1 may have the same or similar configuration. However, the UE may have various configurations, and FIG. 3 does not limit the scope of the present disclosure to any specific implementation of the UE.

[0049] As illustrated in FIG. 3, the UE (116) includes an antenna (305), a radio frequency (RF) transceiver (310), a transmit (TX) processing circuit (315), a microphone (320), and a receive (RX) processing circuit (325). The UE (116) also includes a speaker (330), a main processor (340), an input / output (I / O) interface (IF) (345), a keypad (350), a display (355), and a memory (360). The memory (360) includes an operating system (OS) program (361) and one or more applications (362).

[0050] The RF transceiver (310) receives an incoming RF signal transmitted by the gNB of the network (100) from the antenna (305). The RF transceiver (310) downconverts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is transmitted to an RX processing circuit (325) that generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuit (325) transmits the processed baseband signal to a speaker (330) (such as for voice data) or a main processor (340) for further processing (such as for web browsing data).

[0051] The TX processing circuit (315) receives analog or digital voice data from the microphone (320) or other outgoing baseband data (such as web data, email, or interactive video game data) from the main processor (340). The TX processing circuit (315) encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver (310) receives the outgoing processed baseband or IF signal from the TX processing circuit (315) and upconverts the baseband or IF signal into an RF signal transmitted through the antenna (305).

[0052] The main processor (340) may include one or more processors or other processing devices and may execute a basic OS program (361) stored in memory (360) to control the overall operation of the UE (116). For example, the main processor (340) may control the reception of a forward channel signal and the transmission of a reverse channel signal by means of an RF transceiver (310), an RX processing circuit (325), and a TX processing circuit (315) according to well-known principles. In some embodiments, the main processor (340) includes at least one microprocessor or microcontroller.

[0053] The main processor (340) may also execute other processes and programs residing in memory (360). The main processor (340) may move data in and out of memory (360) as required by the executing process. In some embodiments, the main processor (340) is configured to execute an application (362) based on an OS program (361) or in response to a signal received from a gNB or operator. The main processor (340) is also coupled to an I / O interface (345) that provides the UE (116) with the ability to connect to other devices, such as laptop computers and handheld computers. The I / O interface (345) is a communication path between these accessories and the main processor (340).

[0054] The main processor (340) is also coupled to the keypad (350) and the display unit (355). An operator of the UE (116) can input data into the UE (116) using the keypad (350). The display (355) may be a liquid crystal display, or another display capable of rendering text and / or at least limited graphics from, for example, a website.

[0055] The memory (360) is coupled to the main processor (340). Part of the memory (360) may include random access memory (RAM), and other parts of the memory (360) may include flash memory or other read-only memory (ROM).

[0056] As described in more detail below, the UE (116) can communicate with a BS such as the BS (102) of FIG. 2 over a network to facilitate downlink synchronization, management of HARQ transmission, and / or implementation of an enhanced PRACH preamble format.

[0057] FIG. 3 illustrates an example of a UE (116), but various modifications to FIG. 3 may be made. For example, various components of FIG. 3 may be combined, further subdivided, or omitted, and additional components may be added as needed. As a specific example, the main processor (340) may be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Additionally, FIG. 3 illustrates a UE (116) configured as a mobile phone or smartphone, but the UE may be configured to operate as other types of mobile or stationary devices.

[0058] FIGS. 4a and 4b illustrate exemplary wireless transmission and reception paths according to various embodiments of the present disclosure. In FIGS. 4a and 4b, for downlink communication, the transmission path (400) may be implemented at a base station (gNB) (102) or a relay station, and the reception path circuit may be implemented at a user device (e.g., the user device (116) of FIG. 1). In another example, for uplink communication, the reception path (450) may be implemented at a base station (e.g., the gNB (102) of FIG. 1) or a relay station, and the transmission path (400) may be implemented at a user device (e.g., the user device (116) of FIG. 1).

[0059] The transmission path (400) includes a channel coding and modulation block (405), a serial-to-parallel (S-to-P) block (410), an inverse Fast Fourier Transform (IFFT) block of size N (415), a parallel-to-serial (P-to-S) block (420), an add cyclic prefix block (425), and an up-converter (UC) (430). The receiving path (450) includes a down-converter (DC) (455), a remove cyclic prefix block (460), a serial-to-parallel (S-to-P) block (465), a Fast Fourier Transform (FFT) block of size N (470), a parallel-to-serial (P-to-S) block (475), and a channel decoding and demodulation block (480).

[0060] At least some of the components in the transmission path (400) and the reception path (450) may be implemented in software, but other components may be implemented by configurable hardware or a combination of software and configurable hardware. In particular, it is noted that the FFT block and IFFT block described in this disclosure may be implemented as configurable software algorithms, wherein the value of size N may be modified depending on the implementation.

[0061] Additionally, the present disclosure relates to embodiments for implementing the Fast Fourier Transform and the inverse Fast Fourier Transform, but this is for illustrative purposes only and should not be construed as limiting the scope of the present disclosure. In alternative embodiments of the present disclosure, it will be understood that the Fast Fourier Transform function and the inverse Fast Fourier Transform function can be easily replaced with the Discrete Fourier Transform (DFT) function and the inverse Discrete Fourier Transform (IDFT) function, respectively. For the DFT and IDFT functions, the values ​​of the N variables can be any integers (i.e., 1, 4, 3, 4, etc.), but for the FFT and IFFT functions, the values ​​of the N variables can be any integers that are powers of 2 (i.e., 1, 2, 4, 8, 16, etc.).

[0062] In the following example, the transmission path (400) is implemented in the BS, and the reception path is implemented in the UE. In the transmission path (400), the channel coding and modulation block (405) receives a set of information bits, applies coding (e.g., LDPC coding), and modulates the input bits to generate a series of frequency-domain modulation symbols (e.g., quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)). The serial-to-parallel block (410) converts the serially modulated symbols into parallel data (i.e., de-multiplexes) to generate N parallel symbol streams, where N is the size of the IFFT / FFT used in the BS (102) and the UE (116). Next, a size N IFFT block (415) performs an IFFT operation on N parallel symbol streams to generate a time-domain output signal. A parallel-to-serial block (420) converts (i.e., multiplexes) the parallel time-domain output symbols from the size N IFFT block (415) to generate a serial time-domain signal. Next, a cyclic prefix addition block (425) inserts a cyclic prefix into the time-domain signal. Finally, an upconverter (430) modulates (e.g., upconverts) the output of the cyclic prefix addition block (425) to an RF frequency for transmission over a wireless channel.The signal can also be filtered in the baseband before being converted to RF frequency.

[0063] The transmitted RF signal reaches the UE (116) after passing through the wireless channel, and a reverse operation with respect to the operation at the gNB (102) is performed. The down-converter (455) down-converts the received signal to a baseband frequency, and the cyclic prefix removal block (460) removes the cyclic prefix to generate a serial time-domain baseband signal. The serial-to-parallel block (465) converts the time-domain baseband signal into a parallel time-domain signal. Then, the size N FFT block (470) performs an FFT algorithm to generate N parallel frequency domain signals. The parallel-to-serial block (475) converts the parallel frequency domain signals into a series of modulated data symbols. The channel decoding and demodulation block (480) demodulates and decodes the modulated symbols to restore the original input data stream.

[0064] Each of the gNBs (101-103) can implement a transmission path (400) similar to transmitting to a user device (111-116) in a downlink and a reception path (450) similar to receiving from a user device (111-116) in an uplink. Likewise, each of the user devices (111-116) can implement a transmission path (400) corresponding to an architecture for transmitting to the gNB (101-103) in an uplink and a reception path (450) corresponding to an architecture for receiving from the gNB (101-103) in a downlink.

[0065] As described in more detail below, the transmission path (400) and the reception path (450) may be implemented in a UE such as the UE (116) of FIG. 3 and a BS such as the BS (102) of FIG. 2 to facilitate downlink synchronization, management of HARQ transmission, and / or implementation of an enhanced PRACH preamble format.

[0066] Although FIGS. 4a and 4b illustrate examples of wireless transmission and reception paths, various modifications may be made to FIGS. 4a and 4b. For example, various components of FIGS. 4a and 4b may be combined, further subdivided, or omitted, and additional components may be added as needed. Additionally, FIGS. 4a and 4b are intended to illustrate examples of types of transmission and reception paths that may be used in a wireless network. Any other suitable architecture may be used to support wireless communication in a wireless network.

[0067] FIG. 5 illustrates an exemplary transmitter according to various embodiments of the present disclosure. The transmitter (500) may be implemented in an electronic device that communicates through a wireless communication network such as a gNB (101) or a UE (111).

[0068] Information bits (510), such as DCI bits or data bits, are encoded by an encoder (520) and then rate-matched to time / frequency resources allocated by a rate matcher (530). The output from the rate matcher (530) is modulated by a modulator (540). The modulated and encoded symbols (545) and DMRS or CSI-RS (550) are mapped by an SC mapping unit (560) based on an SC selected by a BW selection unit (565). An inverse Fast Fourier Transform (IFFT) is performed by an IFFT unit (570), and a cyclic prefix (CP) is added by a CP insertion unit (580). The generated signal is filtered into a filtered signal (595) generated by a filter (590), which is transmitted by a radio frequency (RF) unit (not shown).

[0069] FIG. 6 illustrates an exemplary receiver according to various embodiments of the present disclosure. The receiver (600) may be implemented in an electronic device that communicates through a wireless communication network such as a gNB (101) or a UE (111).

[0070] The received signal (610) is filtered by a filter (620) and then passes through a CP removal unit (630) that removes circular prefixes. An IFFT unit (640) applies a Fast Fourier Transform (FFT), and the generated signal is provided to an SC demapping unit (650). The SC demapping unit (650) demappings the SC selected by the BW selection unit (655). The received symbol is demodulated by a channel estimator and demodulation unit (660). A rate de-matcher (670) restores the rate match, and a decoder (280) decodes the generated bit to provide an information bit (690).

[0071] Each of the gNBs (101-103) can implement a transmission path (400) for transmitting to the UE (111-116) in the downlink and a receiver (600) for receiving from the UE (111-116) in the uplink. Similarly, each of the UEs (111-116) can implement a transmission path (400) for transmitting to the gNB (101-103) in the uplink and a receiver (600) for receiving from the gNB (101-103) in the downlink.

[0072] As described in more detail below, the transmitter (500) and receiver (600) may be included in a UE and BS such as a UE (116) and BS (102) to facilitate downlink synchronization, management of HARQ transmission, and / or implementation of an enhanced PRACH preamble format.

[0073] Each of the components of FIGS. 5 and 6 may be implemented using only hardware or a combination of hardware and software / firmware. As a specific example, at least some of the components of FIGS. 5 and 6 may be implemented in software, but other components may be implemented by configurable hardware or a combination of software and configurable hardware. For example, the IFFT block (570) may be implemented as a configurable software algorithm.

[0074] Additionally, although the use of IFFT has been described, this is merely an example and should not be construed as limiting the scope of the present disclosure. Other types of transforms, such as the Discrete Fourier Transform (DFT) and Inverse Discrete Fourier Transform (IDFT) functions, may be used.

[0075] FIGS. 5 and 6 illustrate examples of wireless transmitters and receivers, but various modifications may be made. For example, the various components of FIGS. 5 and 6 may be combined, further subdivided, or omitted, and additional components may be added as needed. Additionally, FIGS. 5 and 6 are intended to illustrate examples of types of transmitters and receivers that may be used in wireless networks. Any other suitable architecture may be used to support wireless communication in wireless networks.

[0076] As discussed below, downlink synchronization in NTN can be achieved through SS / PBCH block design, configuration of CORESET#0, and / or enhancements to the downlink synchronization procedure.

[0077] FIG. 7 illustrates the SS / PBCH block configuration for an NR Rel-15 according to various embodiments of the present disclosure. The NR Rel-15 supports multiple synchronization signals and physical broadcast channel blocks (SS / PBCH blocks or SSBs) in each carrier frequency range.

[0078] Each SS / PBCH block (700) has four consecutive OFDM (orthogonal frequency division multiplexing) symbols. The first symbol is mapped to the PSS (primary synchronization signal), the second and fourth symbols are mapped to the PBCH, and the third symbol is mapped to both the SSS (secondary synchronization signal) and the PBCH. The same SS / PBCH block configuration applies to all carrier frequency ranges supported in NR from 0 GHz to 52.6 GHz. The transmit bandwidth of the PSS and SSS (e.g., 12 resource blocks (RB)) is smaller than the transmit bandwidth of the entire SS / PBCH block (e.g., 20 RB). In all RBs mapped to the PBCH, three of the twelve resource elements (REs) are mapped to the demodulation reference signal (DMRS) of the PBCH, three REs are evenly distributed across the PRB, and the starting position of the first RE is based on the cell identity (ID). Additionally, NR Rel-15 supports one or two subcarrier spacings (SCS) for the SS / PBCH block for a given band, and the same SCS is utilized for the PSS, SSS, and PBCH (including the DMRS). For a carrier frequency range of 0 GHz to 6 GHz, 15 kHz and / or 30 kHz may be utilized for the SCS of the SS / PBCH block. For a carrier frequency range of 6 GHz to 52.6 GHz, 120 kHz and / or 240 kHz can be used for the SCS of the SS / PBCH block.

[0079] In some embodiments, the sequence constituting the PSS is based on an M-sequence having a cyclic shift to represent cell ID information returned by the PSS, and the sequence constituting the SSS is based on a Gold-sequence (exclusive or two M-sequences). Each M-sequence constituting the Gold-sequence performs a cyclic shift to represent cell ID information returned by the SSS.

[0080] FIG. 8 illustrates an SS / PBCH block pattern in the time domain for NR Rel-15 according to various embodiments of the present disclosure.

[0081] In NR Rel-15, SS / PBCH blocks can be transmitted via beam-sweeping to network implementation, and multiple candidate locations for transmitting SS / PBCH blocks are predefined within the unit of a half frame. As can be seen in FIG. 8, the mapping pattern (800a) for one slot for 15 kHz as a reference SCS for frequency range 1 (FR1) is 410 MHz to 7.125 GHz, and the mapping pattern (800b) for 60 kHz as a reference SCS for frequency range 2 (FR2) is 24.25 GHz to 52.6 GHz. Two mapping patterns were designed for the 30 kHz SCS of the SS / PBCH block. Pattern 1 is used in the non-LTE NR coexistence band, and Pattern 2 is used in the LTE-NR coexistence band.

[0082] FIG. 9 illustrates the SS / PBCH block location within a half frame for NR Rel-15 according to various embodiments of the present disclosure.

[0083] The maximum number of SS / PBCH blocks in a period represented as L_SSB is determined according to the carrier frequency range. For a carrier frequency range of 0 GHz to 3 GHz, L_SSB is 4. For a carrier frequency range of 3 GHz to 6 GHz, L_SSB is 8. For a carrier frequency range of 6 GHz to 52.6 GHz, L_SSB is 64. The determination of slots within a half-frame unit (900) containing candidate locations for SS / PBCH blocks for each combination of SSB SCS and L_SSB is shown in FIG. 9.

[0084] In the initial cell selection, the user device (UE) assumes a default SSB burst set period of 20ms, and to detect non-standalone NR cells, the network provides the UE with information on one SSB burst set periodicity per frequency carrier and, if possible, information for deriving the measurement timing / duration.

[0085] Due to the spread of delay between the transmitter and receiver in NTN, NR enhancement is proposed to solve the downlink synchronization problem in NTN. The form of downlink synchronization includes SS / PBCH block design, configuration of CORESET#0, and enhancement of the downlink (DL) synchronization procedure.

[0086] In NTN, a satellite or UAS platform typically generates multiple beams across a given service area defined by a line of sight. The beam footprint is typically elliptical and depends on the onboard antenna diagram and the minimum elevation angle. An example of a beam footprint is shown in Fig. 10.

[0087] FIG. 10 illustrates beam footprints generated by satellites according to various embodiments of the present disclosure. In particular, TNT (1000) includes satellites (154) that generate beam footprints (1002) corresponding to each cell. In one aspect of this embodiment, frequency reuse may occur between different footprints, for example, in the case of footprints with sufficient distance.

[0088] In one approach, a UE in a given footprint may assume that there is at most one SS / PBCH block transmitted within a period of SS / PBCH block transmission. In one example, where there is no frequency reuse between different footprints, there is at most one SS / PBCH block transmitted on each frequency layer corresponding to the synchronization raster. In another example, where there is frequency reuse between different footprints, there may be multiple SS / PBCH blocks transmitted on each frequency layer corresponding to the synchronization raster, but at most one of these is assumed by the UE within a given footprint.

[0089] In another approach, a UE in a given footprint assumes that there may be at most one or more SS / PBCH blocks transmitted within a period of SS / PBCH block transmission, and further assumes that the SS / PBCH blocks transmitted on a given frequency layer are quasi-co-located. In one embodiment, the number of quasi-co-located SS / PBCH blocks within a period may be predefined in the specification, and the UE assumes that all quasi-co-located SS / PBCH blocks are transmitted when any of the quasi-co-located SS / PBCH blocks are detected. In another embodiment, the indication of the quasi-co-located SS / PBCH blocks actually transmitted within a period is provided by remaining minimum system information (RMSI) content, e.g., a bitmap.

[0090] In another embodiment, the UE assumes that at least one footprint corresponds to one cell.

[0091] In one approach, it is assumed that a UE in a given footprint has at most one SS / PBCH block transmitted within a cycle of SS / PBCH block transmission.

[0092] In another approach, a UE in a given footprint assumes that there may be at most one or more SS / PBCH blocks transmitted within a period of SS / PBCH block transmission, and further assumes that the SS / PBCH blocks transmitted on a given frequency layer are QCLed. In one embodiment, the number of QCLed SS / PBCH blocks within a period is predefined in the specification, and the UE assumes that all QCLed SS / PBCH blocks are transmitted when it detects any of the QCLed SS / PBCH blocks. In another embodiment, the indication of the QCLed SS / PBCH blocks actually transmitted within a period is by RMSI content, for example, a bitmap.

[0093] In one embodiment, the band for operating the NTN has a minimum carrier bandwidth of 30 MHz, which is 160 RB in terms of a 15 kHz SCS or 78 RB in terms of a 30 kHz SCS.

[0094] In one approach, a 15 kHz SCS is supported for the SS / PBCH block in the band for operating the NTN with a minimum carrier bandwidth of 30 MHz, and the channel center of the band for operating the NTN with a minimum carrier bandwidth of 30 MHz can be changed by a small step size (e.g., 15 kHz, 30 kHz, or 100 kHz).

[0095] In one example of this approach, CORESET#0 having a bandwidth of 24 RB in terms of a 15 kHz SCS is supported, and multiplexed with an SS / PBCH block in a manner where the bandwidths overlap and occur at different time instances, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to 2 RB in terms of the SCS of CORESET#0.

[0096] In another example of this approach, CORESET#0 with a bandwidth of 48 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to either 0 or 28 RB in terms of the SCS of CORESET#0.

[0097] In another example of this approach, CORESET#0 with a bandwidth of 96 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to one of 0, 38, or 76 RB in terms of the SCS of CORESET#0.

[0098] In another example of this approach, CORESET#0 with a bandwidth of 24 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to either 0 or 14 RB in terms of the SCS of CORESET#0.

[0099] In another example of this approach, CORESET#0 with a bandwidth of 48 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to one of 0, 19, or 38 RB in terms of the SCS of CORESET#0.

[0100] In another approach, a 30 kHz SCS is supported for an SS / PBCH block on the band for operating the NTN with a minimum carrier bandwidth of 30 MHz, and the channel center of the band for operating the NTN with a minimum carrier bandwidth of 30 MHz can be changed in small step sizes (e.g., 15 kHz, 30 kHz, or 100 kHz).

[0101] In one example of this approach, CORESET#0 having a bandwidth of 48 RB in terms of a 15 kHz SCS is supported, and multiplexed with an SS / PBCH block in a manner where the bandwidths overlap and occur at different time instances, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to 0 or 8 RB in terms of the SCS of CORESET#0.

[0102] In another example of this approach, CORESET#0 with a bandwidth of 96 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to either 0 or 56 RB in terms of the SCS of CORESET#0.

[0103] In another example of this approach, CORESET#0 with a bandwidth of 24 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to either 0 or 4 RB in terms of the SCS of CORESET#0.

[0104] In another example of this approach, CORESET#0 with a bandwidth of 48 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be set to either 0 or 28 RB in terms of the SCS of CORESET#0.

[0105] In another approach, a 15 kHz SCS is supported for the SS / PBCH block in the band for operating the NTN with a minimum carrier bandwidth of 30 MHz, and the channel center of the band for operating the NTN with a minimum carrier bandwidth of 30 MHz is fixed. In this approach, if the multiplexing between CORESET#0 and the SS / PBCH block occurs in different time instances and is performed in such a way that the bandwidths overlap, there may be a single synchronization raster entry within the 30 MHz minimum carrier bandwidth, and the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block may be fixed, and the fixed frequency offset may be determined by the following when CORESET#0 and the SS / PBCH block are center-aligned in the frequency domain:

[0106] F_offset = (BW_CORESET#0 - BW_SSB*SCS_SSB / SCS_CORESET#0) / 2.

[0107] Alternatively, a fixed frequency offset can be determined by the following when the CORESET#0 and SS / PBCH blocks are edge-aligned (top RB) in the frequency domain:

[0108] F_offset = BW_CORESET#0 - BW_SSB*SCS_SSB / SCS_CORESET#0.

[0109] Alternatively, a fixed frequency offset can be determined by the following when CORESET#0 and the SS / PBCH block are edge-aligned (lowest RB) in the frequency domain, where BW_CORESET#0 is the bandwidth of CORESET#0, BW_SSB is the bandwidth of the SS / PBCH block, SCS_SSB is the SCS of the SS / PBCH block, and SCS_CORESET#0 is the SCS of CORESET#0:

[0110] F_offset = 0.

[0111] In one example of this approach, CORESET#0 with a bandwidth of 24 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that the bandwidths overlap and occur at different time instances, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., centered) as 2 RB in terms of the SCS of CORESET#0.

[0112] In another example of this approach, CORESET#0 with a bandwidth of 24 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., edge-aligned) as 0 RB or 4 RB in terms of the SCS of CORESET#0.

[0113] In another example of this approach, CORESET#0 with a bandwidth of 48 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that the bandwidths overlap and occur at different time instances, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., centered) as 14 RB in terms of the SCS of CORESET#0.

[0114] In another example of this approach, CORESET#0 with a bandwidth of 48 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and have overlapping bandwidths, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., edge-aligned) as 0 RB or 28 RB in terms of the SCS of CORESET#0.

[0115] In another example of this approach, CORESET#0 with a bandwidth of 96 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., centered) as 38 RB in terms of the SCS of CORESET#0.

[0116] In another example of this approach, CORESET#0 with a bandwidth of 96 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., edge-aligned) as 0 RB or 76 RB in terms of the SCS of CORESET#0.

[0117] In another example of this approach, CORESET#0 with a bandwidth of 144 RB in terms of a 15 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., centered) as 62 RB in terms of the SCS of CORESET#0.

[0118] In another example of this approach, CORESET#0 with a bandwidth of 144RB in terms of a 15kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., edge-aligned) as 0RB or 124RB in terms of the SCS of CORESET#0.

[0119] In another example of this approach, CORESET#0 with a bandwidth of 24 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., center-aligned) as 7 RB in terms of the SCS of CORESET#0.

[0120] In another example of this approach, CORESET#0 with a bandwidth of 24 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and have overlapping bandwidths, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., edge-aligned) as 0 RB or 14 RB in terms of the SCS of CORESET#0.

[0121] In another example of this approach, CORESET#0 with a bandwidth of 48 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and have overlapping bandwidths, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., centered) as 19 RB in terms of the SCS of CORESET#0.

[0122] In another example of this approach, CORESET#0 with a bandwidth of 48RB in terms of a 30kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and their bandwidths overlap, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., edge-aligned) as 0RB or 38RB in terms of the SCS of CORESET#0.

[0123] In another example of this approach, CORESET#0 with a bandwidth of 72 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that the bandwidths overlap and occur at different time instances, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., centered) as 31 RB in terms of the SCS of CORESET#0.

[0124] In another example of this approach, CORESET#0 with a bandwidth of 72 RB in terms of a 30 kHz SCS is supported and multiplexed with an SS / PBCH block in such a way that they occur at different time instances and have overlapping bandwidths, and then the frequency offset between the lowest RB of CORESET#0 and the lowest RB of the SS / PBCH block can be fixed (e.g., edge-aligned) as 0 RB or 62 RB in terms of the SCS of CORESET#0.

[0125] Since downlink synchronization performance can be degraded due to Doppler shift, improvements to the downlink synchronization procedure are necessary.

[0126] In one embodiment, a UE operating for NTN assumes that SS / PBCH blocks within a period (e.g., initial access of 20ms) can be repeated in the time domain to improve coverage. The repetition is based on the QCL assumption, and specific signals / channels (e.g., DMRS sequences of PBCH) can be changed in the repeated SS / PBCH blocks.

[0127] In one approach, the UE assumes that SS / PBCH blocks with SS / PBCH block indices i and i+1 are QCL, where i is an even number. For example, two SS / PBCH blocks within the same slot are QCL. In one aspect of this approach, the UE assumes that either both of the QCLed SS / PBCH blocks are transmitted or neither is transmitted. In another expectation of this approach, the UE assumes a bitmap to represent the actually transmitted SS / PBCH blocks, which take the same value (e.g., 0 or 1) for the (i-1) and i-th bits.

[0128] In a different approach, the UE assumes that all SS / PBCH blocks are QCLed within the SS / PBCH block transmission cycle. In one example, the actual number of SS / PBCH blocks transmitted can be fixed for the NTN, and it is assumed that all actually transmitted SS / PBCH blocks are QCLed. In another example, the actual number of SS / PBCH blocks transmitted is configurable, and it is assumed that all actually transmitted SS / PBCH blocks are QCLed.

[0129] In another approach, the UE assumes that the SS / PBCH block is repeated based on the capabilities of the Global Navigation Satellite System (GNSS). For example, if the UE is unable to perform GNSS, the UE may assume that the SS / PBCH block can be repeated within a period (e.g., 20ms for initial access).

[0130] In another embodiment, the UE assumes at least one numerology for SS / PBCH block detection in the initial access procedure, and the UE may need to blind detect the numerology of the SS / PBCH block if the supported numerology is greater than 1.

[0131] In one approach, if the UE can distinguish the type of payload, for example, transparent or regenerative type, the UE can determine the single numerology of the SS / PBCH block in the initial access.

[0132] In another embodiment, a UE operating for NTN assumes that SS / PBCH blocks can be repeated in the frequency domain to improve coverage, where repetition refers to the QCL assumption, and specific signals / channels (e.g., PSS / SSS) can be changed in the repeated SS / PBCH blocks.

[0133] FIG. 11 illustrates an example of SS / PBCH block repetition in the frequency domain according to various embodiments of the present disclosure.

[0134] In one embodiment, the number of repeating SS / PBCH blocks in the frequency domain is fixed. For example, the UE assumes that a set of SS / PBCH block bursts (1100a) is repeated once at a different frequency location as an SS / PBCH block burst (1100b).

[0135] In another aspect, the UE assumes that it shares the same time domain information for a transmission including at least one of a set of SS / PBCH block bursts and repetitions thereof, a half frame including the transmission thereof, or an SS / PBCH block actually transmitted.

[0136] In another modality, the UE assumes the numerology of the first SS / PBCH block burst set, and its repetition is identical.

[0137] In another aspect, where the first SS / PBCH block and the second SS / PBCH block have the same SS / PBCH block index, the UE assumes that the first SS / PBCH block of the SS / PBCH block burst set is QCLed to the second SS / PBCH block of the repeated SS / PBCH block burst set in the frequency domain.

[0138] In another embodiment, the UE has a first SS / PBCH block burst set located on a synchronization raster entry, the first SS / PBCH block burst set serves as a cell definition SS / PBCH block, and iterations of the first SS / PBCH block burst set are not located on the synchronization raster entry (so as not to be visible in the initial cell search).

[0139] In another embodiment, the UE may assume a fixed relative position in the frequency domain between a first set of SS / PBCH block bursts and its repetitions. In one approach, the offset between the lowest RB of the first set of SS / PBCH block bursts and the lowest RB of its repetitions may be fixed. For example, the offset is fixed as 20 RB (e.g., two sets of SS / PBCH block bursts are adjacent to each other in the frequency domain, with no frequency gap between them).

[0140] In another aspect, the UE may assume a fixed relationship between the cell ID returned by the first SS / PBCH block burst set and its repetitions. In one approach, the UE may assume that the cell ID returned by the first SS / PBCH block burst set is identical to the cell ID returned by its repetitions. In another approach, the UE may assume that the cell ID returned by the first SS / PBCH block burst set has a fixed offset compared to the cell ID returned by its repetitions. In one example of this approach, the cell IDs for the group of SS / PBCH block burst sets and their repetitions are consecutive and increase according to the frequency position within the group.

[0141] FIG. 12 illustrates a conventional PRACH preamble format having a long sequence, and FIG. 13 illustrates a conventional PRACH preamble format having a short sequence. Aspects of an improved PRACH preamble format design according to various embodiments of the present disclosure may relate to the sequence length used in the PRACH preamble, the SCS supported in the PRACH preamble, and the PRACH preamble configuration. Two sets of PRACH preamble formats are described in the present disclosure. A first set of PRACH preamble formats is based on an SCS scaled from 1.25 kHz, and a second set of PRACH preamble formats is based on an SCS scaled from 15 kHz.

[0142] In one embodiment, the enhanced PRACH preamble format is at least 839 (e.g., L_RA 839) has a ZC-sequence (e.g., denoted as L_RA) with a length of 1.25 kHz (e.g., SCS_RA 1.25 kHz / ρ) and a subcarrier interval (e.g., denoted as SCS_RA) scaled from 1.25 kHz.

[0143] For example, at least one of the following L_RAs in Table 1 may be supported.

[0144] Table 1. Examples of ZC-sequence lengths.

[0145]

[0146] In one approach of this embodiment, a PRACH format without a reserved gap after the sequence is supported.

[0147] FIGS. 14a and 14b illustrate an exemplary PRACH format without a reserved gap according to various embodiments of the present disclosure. Such a PRACH format is also illustrated in Table 2. In this example, the ZC-sequence length (e.g., L_RA) may be from the example in Table 1, and the SCS (e.g., SCS_RA) may be scaled from 1.25 kHz such that SCS_RA = 1.25 / ρ, where ρ is the SCS scaling factor for 1.25 kHz (e.g., ρ may be in the form ρ = 2^v, where v is an integer, positive, zero, or negative). Note that N_CP, N_SEQ, and N_total are scaled by ρ.

[0148] Table 2. Exemplary PRACH preamble format.

[0149]

[0150] In another approach of this embodiment, a PRACH format with a gap reserved after the sequence is supported.

[0151] FIGS. 15a and 15b illustrate a PRACH format having a reserved gap according to various embodiments of the present disclosure. Such exemplary PRACH formats are also illustrated in Table 3.

[0152] The ZC-sequence length (e.g., L_RA) may be from the example in Table 1, and the SCS (e.g., SCS_RA) may be scaled from 1.25 kHz such that SCS_RA = 1.25 / ρ, where ρ is the SCS scaling factor for 1.25 kHz (e.g., ρ may be of the form ρ = 2^v, where v is an integer, positive, zero, or negative). Note that N_CP, N_SEQ, N_GAP, and N_total are scaled by ρ.

[0153] Table 3. Exemplary PRACH preamble format.

[0154]

[0155] In one embodiment, the enhanced PRACH preamble format is at least 139 (e.g., L_RA 139) has a ZC-sequence with a length of 139) and a subcarrier interval (e.g., denoted as SCS_RA) scaled from 15 kHz (e.g., SCS_RA 15 / ρ).

[0156] For example, at least one of the following L_RAs in Table 4 may be supported, SCS_RA = 15 / ρ, where ρ is the SCS ratio for 15 kHz (e.g., ρ may be of the form ρ = 2^v, where v is an integer, positive, zero, or negative).

[0157] Table 4. Examples of ZC-sequence lengths.

[0158]

[0159] In one approach of this embodiment, a PRACH format without a reserved gap after the sequence is supported.

[0160] FIG. 16 illustrates a PRACH preamble format without a reserved gap according to various embodiments of the present disclosure. Such exemplary PRACH formats are also illustrated in Table 5. In this example, the ZC-sequence length (e.g., L_RA) may be from the example in Table 4, and the SCS (e.g., SCS_RA) may be scaled from 15 kHz such that SCS_RA = 15 / ρ, where ρ is the SCS scaling factor for 15 kHz (e.g., ρ may be of the form ρ = 2^v, where v is an integer, positive, zero, or negative). Note that N_CP and N_SEQ are scaled by ρ.

[0161] Table 5. Exemplary PRACH preamble format.

[0162]

[0163] In another approach of this embodiment, a PRACH format with a gap reserved after the sequence is supported.

[0164] FIG. 17 illustrates an additional PRACH format with a gap according to various embodiments of the present disclosure. The PRACH format is also illustrated in Table 6.

[0165] In this example, the ZC-sequence length (e.g., L_RA) may be from the example in Table 4, and the SCS (e.g., SCS_RA) may be scaled from 15 kHz such that SCS_RA = 15 / ρ, where ρ is the SCS scaling factor for 15 kHz (e.g., ρ may be of the form ρ = 2^v, where v is an integer, positive, zero, or negative). Note that N_CP and N_SEQ are scaled by ρ.

[0166] Table 6. Exemplary PRACH preamble format.

[0167]

[0168] As mentioned above, in the case of NTN, there is generally a large propagation delay between the transmitter and the receiver, and the specific maximum round-trip delay (RTD) varies depending on the implementation scenario. Table 7 shows exemplary maximum RTDs for some typical NTN scenarios.

[0169] Table 7. Exemplary maximum round-trip delay for the NTN scenario.

[0170]

[0171] Disabling HARQ feedback may be useful in some NTN scenarios. Accordingly, additional aspects of the present disclosure include disabling HARQ feedback, an overriding rule for disabling HARQ feedback, HARQ enhancement using UE auxiliary information, DCI formatting after disabling HARQ feedback, and a method for restoring reliability after disabling HARQ feedback.

[0172] In one embodiment, HARQ feedback may be configured to be disabled by gNB. Various methods of this embodiment are discussed below.

[0173] Method 1. HARQ feedback can be configured to be disabled by an upper layer parameter (e.g., an RRC parameter). It is assumed that the UE maintains the HARQ feedback disabled for all transmissions until the upper layer parameter indicates that HARQ feedback is enabled. At least one approach or a combination of approaches for this method may be supported.

[0174] In the first approach of Method 1, the upper-level parameter for disabling HARQ feedback may be cell-specific. For example, at least one field of ServingCellConfigCommon is used to indicate whether HARQ feedback is disabled. In another example, at least one field of ServingCellConfig is used to indicate whether HARQ feedback is disabled.

[0175] In the second approach of Method 1, the upper-level parameter for disabling HARQ feedback may be cell group specific. For example, at least one field of CellGroupConfig is used to indicate whether HARQ feedback is disabled.

[0176] In the third approach of Method 1, the upper-level parameter for disabling HARQ feedback may be UE-specific. For example, at least one field of ServingCellConfig is used to indicate whether HARQ feedback is disabled.

[0177] In the fourth approach of Method 1, at least one upper-level parameter is used to set whether DL HARQ feedback is disabled.

[0178] In the fifth approach of this method, at least one upper-level parameter is used to set whether UL HARQ feedback is disabled.

[0179] In the sixth approach of Method 1, at least one upper-level parameter is used to set whether DL and UL HARQ feedback are jointly disabled.

[0180] Method 2. HARQ feedback can be configured to be disabled by the DCI format. At least one approach or combination of approaches for this method may be supported.

[0181] In the first approach of Method 2, the DCI format may be the DCI format scheduling of the cell's PUSCH (e.g., DCI format 0_0 and / or DCI format 0_1). The UE assumes that the transmission of the PUSCH scheduled by the DCI format has HARQ feedback disabled.

[0182] In the second approach of Method 2, the DCI format may be the DCI format scheduling of the cell's PDSCH (e.g., DCI format 1_0 and / or DCI format 1_1). The UE assumes that the transmission of the PDSCH scheduled by the DCI format has HARQ feedback disabled.

[0183] In the third approach of Method 2, the DCI format may be a DCI format that notifies a group of information of the UE (e.g., DCI format 2_0 and / or DCI format 2_1). The UE assumes that transmission HARQ feedback is disabled for the same period as the period during which the notified information is valid.

[0184] In the fourth approach of Method 2, a new distinct field of the DCI format may be used to indicate whether HARQ feedback is disabled. In a non-limiting embodiment, the field is 1 bit wide.

[0185] In the fifth approach of Method 2, the value of an existing field in the DCI format (e.g., a reserved value) can be used to indicate that HARQ feedback is disabled (e.g., by setting the field to a non-numerical value). In one example, the value of an existing field of the HARQ processor number in the DCI format (e.g., a reserved value) can be used to indicate that HARQ feedback is disabled (e.g., by setting the field to a non-numerical value). In another example, the value of an existing field of the downlink allocation index in the DCI format (e.g., a reserved value) can be used to indicate that HARQ feedback is disabled (e.g., by setting the field to a non-numerical value). In yet another example, the value of an existing field of the PUCCH resource indicator in the DCI format (e.g., a reserved value) can be used to indicate that HARQ feedback is disabled (e.g., by setting the field to a non-numerical value). In another example, the value of an existing field of the PDSCH-to-HARQ_feedback timing indicator in DCI format (e.g., a reserved value) can be used to indicate that HARQ feedback is disabled (e.g., by setting the field to a non-numerical value). In another example, the value of an existing field of the TPC command for a scheduled PUCCH in DCI format (e.g., a reserved value) can be used to indicate that HARQ feedback is disabled (e.g., by setting the field to a non-numerical value). In another example, the value of an existing field of the TPC command for a scheduled PUSCH in DCI format (e.g., a reserved value) can be used to indicate that HARQ feedback is disabled (e.g., by setting the field to a non-numerical value).

[0186] Method 3. HARQ feedback may be configured to be disabled by system information. In the first approach of Method 3, an indication of whether HARQ feedback is disabled may be in the contents of the PBCH. In the second approach of Method 3, an indication of whether HARQ feedback is disabled may be in the RMSI. In the third approach of Method 3, an indication of whether HARQ feedback is disabled may be in the OSI. In the fourth approach of Method 3, an indication of whether HARQ feedback is disabled may be in the paging.

[0187] In one embodiment, as described above, there may be at least one method and / or approach supported for disabling HARQ feedback, and the overriding rule of indication by at least one method and / or approach may be specified from the perspective of the UE.

[0188] In a single approach, if both a method using a higher-level parameter to indicate whether HARQ feedback is enabled and a method using system information to indicate whether HARQ feedback is enabled are supported, the UE assumes that the indication by the higher-level parameter overrides the indication by the system information during the period the higher-level parameter is valid.

[0189] In another approach, where both methods using upper-layer parameters to indicate whether HARQ feedback is enabled and using DCI format to indicate whether HARQ feedback is enabled are supported, the UE assumes that the indication by DCI format takes precedence over the indication by upper-layer parameters for transmissions of PUSCH or PDSCH scheduled by DCI format.

[0190] In another approach, where both a method using system information to indicate whether HARQ feedback is enabled and a method using the DCI format to indicate whether HARQ feedback is enabled are supported, the UE assumes that the indication by the DCI format takes precedence over the indication by the system information for transmissions of PUSCH or PDSCH scheduled by the DCI format.

[0191] In one embodiment, the UE may provide gNB assistance information related to HARQ operations. In one approach, the UE may provide gNB assistance information related to disabling HARQ feedback through upper-level parameters. In one embodiment, assistance information related to disabling HARQ may be included in the RRC parameter UEAssistanceInformation. In another embodiment, assistance information related to HARQ operations may include soft buffer information for receiving transmissions.

[0192] In another embodiment, auxiliary information related to a HARQ operation may include a request to explicitly disable or enable HARQ feedback. In another embodiment, auxiliary information related to a HARQ operation may include a request to disable a set of HARQ feedback, and / or a request to enable a set of HARQ feedback (e.g., by indicating an index of HARQ feedback). In another embodiment, auxiliary information related to a HARQ operation may include a request to increase the number of HARQ feedback. In another embodiment, auxiliary information related to a HARQ operation may include a request to decrease the number of HARQ feedback.

[0193] In another aspect, a UE capable of providing auxiliary information related to HARQ operations in RRC_CONNECTED may initiate a procedure if at least one of the following is configured to do so, detects full utilization of the soft buffer, or detects that full utilization of the soft buffer is no longer being experienced, or prefers to send a request to disable HARQ feedback, prefers to send a request to enable HARQ feedback, prefers to send a request to increase the number of HARQ feedback, prefers to send a request to decrease the number of HARQ feedback, or prefers to send a request to disable a set of HARQ feedback and / or enable a set of HARQ feedback.

[0194] In another embodiment, the UE must set the content of the UEAssistanceInformation message for auxiliary information related to HARQ operations in at least one of the following cases: when detecting full utilization of the soft buffer, or when detecting that full utilization of the soft buffer is no longer being experienced, or when preferring to send a request to disable HARQ feedback, or preferring to send a request to enable HARQ feedback, or preferring to send a request to increase the number of HARQ feedback, or preferring to send a request to decrease the number of HARQ feedback, or preferring to disable a set of HARQ feedback and / or send a request to enable a set of HARQ feedback.

[0195] In another aspect, the UE assumes that the DL HARQ feedback is disabled immediately after the DL HARQ feedback notifies the gNB of full utilization of the soft buffer or a request to disable HARQ feedback.

[0196] In another approach, the UE can provide gNB auxiliary information related to the HARQ operation through HARQ ACK / NACK feedback.

[0197] In one embodiment, auxiliary information related to the HARQ operation may include soft buffer information for receiving transmissions.

[0198] In another embodiment, auxiliary information related to HARQ operations may include a request to explicitly disable or enable HARQ feedback.

[0199] In another aspect, in addition to ACK and NACK, there may be a new distinct state reported in the HARQ ACK / NACK feedback indicating the UE's request for a HARQ operation.

[0200] In another embodiment, there may be a HARQ codebook pattern representing a UE's request for a HARQ operation. For example, all NACK codebooks can be utilized by the UE to inform the gNB to disable HARQ feedback.

[0201] In one embodiment, at least one field associated with HARQ in the DCI format may be reserved or determined to be 0 bits wide after HARQ feedback is disabled.

[0202] In one embodiment, at least one field associated with HARQ in the DCI format may be reserved or determined to be 0 bits wide after HARQ feedback is disabled according to the DCI format.

[0203] In one approach, at least one field related to DL HARQ in the DCI format can be reserved after DL HARQ feedback is disabled when the DCI format is DCI format 1_0.

[0204] In one example, for DCI format 1_0 having a CRC scrambled by C-RNTI (not for random access procedures initialized by PDCCH sequence) or CS-RNTI or MCS-C-RNTI, after DL HARQ feedback is disabled, at least one of the following fields in the DCI format: HARQ process number, downlink allocation index, TPC instruction for scheduled PUCCH, PUCCH resource indicator, or PDSCH-to-HARQ_feedback timing indicator may be reserved.

[0205] In another example, for DCI format 1_0 with a CRC scrambled by TC-RNTI, after DL HARQ feedback is disabled, at least one of the following fields in the DCI format: the HARQ process number, the TPC instruction for the scheduled PUCCH, the PUCCH resource indicator, or the PDSCH-to-HARQ_feedback timing indicator may be reserved. In this example, note that the downlink allocation index is reserved regardless of whether DL HARQ is enabled or disabled.

[0206] In another approach, at least one field associated with DL HARQ in the DCI format can be determined to be 0 bits wide after DL HARQ feedback is disabled when the DCI format is DCI format 1_1.

[0207] In one example, for DCI format 1_1 having a CRC scrambled by C-RNTI or CS-RNTI or MCS-C-RNTI, after DL HARQ feedback is disabled, at least one of the following fields in the DCI format: HARQ process number, downlink allocation index, TPC instruction for scheduled PUCCH, PUCCH resource indicator, or PDSCH-to-HARQ_feedback timing indicator may be determined to be 0 bits wide.

[0208] In another approach, at least one field related to UL HARQ in the DCI format can be reserved after UL HARQ feedback is disabled when the DCI format is DCI format 0_0.

[0209] In one example, for DCI format 0_0 with a CRC scrambled by C-RNTI or CS-RNTI or MCS-C-RNTI, after UL HARQ feedback is disabled, at least one of the following fields in the DCI format: HARQ process number or TPC command for scheduled PUSCH may be reserved.

[0210] In another example, for DCI format 0_0 with a CRC scrambled by TC-RNTI, after UL HARQ feedback is disabled, at least one of the following fields in the DCI format: HARQ process number or TPC command for scheduled PUSCH may be reserved.

[0211] In another approach, at least one field related to UL HARQ in the DCI format can be determined to be 0 bits wide after UL HARQ feedback is disabled when the DCI format is DCI format 0_1.

[0212] In one example, for DCI format 0_1 ​​having a CRC scrambled by C-RNTI or CS-RNTI or SP-CSI-RNTI or MCS-C-RNTI, after UL HARQ feedback is disabled, at least one of the following fields in the DCI format: HARQ process number, or first downlink allocation index, or second downlink allocation index, or TPC instruction for scheduled PUSCH may be determined to be 0 bit width.

[0213] In another aspect, when at least one field associated with HARQ in the DCI format can be reserved, the reserved field can also be set to a default value (e.g., a value of all zeros).

[0214] In one embodiment, transmissions for reliability recovery may be enhanced after HARQ feedback is disabled. In one approach for enhancing transmissions, one transmission may be repeated with the same RV in each transmission, and parameters for enhancing transmissions include at least one of the number of repetitions or the repetition index.

[0215] In a different approach for enhancing transmission, a single TB may be transmitted multiple times with different RVs in each transmission, and a parameter for enhancing transmission includes at least one of the number of transmissions or the RV value for each transmission. In one example, the RV value for enhancing transmission may be either 0 or 3.

[0216] In one approach, when the UE knows that HARQ feedback is disabled, enhancement for the transmit is assumed by the UE without explicit configuration. In this approach, when the UE knows that HARQ feedback is disabled, the parameters for enhancement for the transmit can be fixed and known to the UE.

[0217] In another approach, enhancement for transmission is set on the UE by the gNB. In one embodiment of this approach, the setting of enhancement for transmission may be independent of the setting of HARQ feedback disable / enable, and enhancement for transmission is not necessarily associated with HARQ feedback disable. In this approach, parameters for enhancement for transmission may be set on the UE.

[0218] In another approach, HARQ disable / enable is co-configured for enhancements to the transmit. For example, parameters for enhancements to the transmit can be co-coded with the HARQ feedback disable indicator.

[0219] FIG. 18 illustrates a flowchart of a process for managing HARQ transmission in a wireless network according to various embodiments of the present disclosure. The operation of the flowchart (1800) can be implemented in a UE such as the UE (116) of FIG. 3.

[0220] The flowchart (1800) starts by receiving downlink control information (DCI) from the base station in the physical downlink control channel (PDCCH) in operation (1802).

[0221] In operation (1804), a decision is made regarding whether the HARQ (hybrid automatic repeat request) feedback is disabled. The decision may be based on a first field in the DCI. In one embodiment, the first field may be a dedicated field for HARQ indication using a reserved bit in the DCI format. In another embodiment, the first field may be an existing field in the DCI format that can be interpreted to disable HARQ feedback.

[0222] In operation (1806), when HARQ feedback is disabled, the second field of the DCI is determined to be either a reserved field or a zero bit width field based on the format of the DCI. In one embodiment, when the format of the DCI is DCI format 0_0 or DCI format 1_0, the second field may be determined to be a reserved field. In another embodiment, when the format of the DCI is DCI format 0_1 ​​or DCI format 1_1, the second field is determined to be a zero bit width field.

[0223] In some embodiments, when the DCI format is DCI format 0_0 or DCI format 0_1, the second field may be a HARQ feedback number field for a scheduled physical uplink shared channel (PUSCH) or a transmit power control (TPC) command field.

[0224] In another embodiment, when the DCI format is DCI format 1_0 or DCI format 1_1, the second field may be a HARQ feedback number field, a transmit power control (TPC) command field for a scheduled physical uplink control channel (PUCCH), a PUCCH resource indicator field, or a PDSCH-to-HARQ feedback timing indicator field.

[0225] In some embodiments, the flowchart (1800) may also include an additional step of generating upper-level parameters including auxiliary information comprising at least one of soft buffer information for reception, a request to disable HARQ feedback, a request to enable HARQ feedback, a request to increase the number of HARQ feedback, or a request to decrease the number of HARQ feedback, and transmitting the upper-level parameters to the BS through the uplink channel.

[0226] Although the present disclosure has been described by exemplary embodiments, various changes and modifications may be presented to those skilled in the art. The present disclosure is intended to include such changes and modifications that fall within the scope of the appended claims. The description in this application should not be interpreted as implying that any specific element, step, or function is an essential element to be included in the claims. The scope of the patented subject matter is defined solely by the claims.

Claims

Claim 1 A user device (UE) in a wireless communication system comprises: at least one transceiver configured to receive downlink control information (DCI) in a physical downlink control channel (PDCCH); and at least one processor operably connected to the at least one transceiver, wherein the at least one processor determines whether hybrid automatic repeat request (HARQ) feedback is disabled based on a first field of the DCI, and, upon the determination that the HARQ feedback is disabled, determines that if the format of the DCI is a first format, a second field of the DCI is a reserved field, and if the format of the DCI is a second format, the second field of the DCI has a width of 0 bits, wherein the first format is one of DCI format 0_0 or DCI format 1_0, and the second format is one of DCI format 0_1 ​​or DCI format 1_1. Claim 2 A user device (UE) in a wireless communication system, wherein the first field is either a dedicated field for indicating that the HARQ feedback is disabled using a reserved bit of the DCI format or an existing field of the DCI format, and the existing field is interpreted as disabling the HARQ feedback. Claim 3 delete Claim 4 delete Claim 5 A user device (UE) in a wireless communication system, wherein, in the case where the DCI format is one of the DCI format 0_0 or the DCI format 0_1, the second field is one of the HARQ feedback number field or the transmit power control (TPC) command field for a scheduled physical uplink shared channel (PUSCH). Claim 6 A user device (UE) in a wireless communication system, wherein, in the case where the DCI format is one of the DCI format 1_0 or the DCI format 1_1, the second field is one of a HARQ feedback number field, a transmit power control (TPC) command field for a scheduled physical uplink shared channel (PUSCH), a PUCCH resource indicator field, or a PDSCH-to-HARQ feedback timing indicator field. Claim 7 A user device (UE) in a wireless communication system, wherein, in claim 1, the at least one processor is further configured to generate upper-level parameters including auxiliary information related to HARQ operation, the auxiliary information includes at least one of soft buffer information for reception, a request to disable the HARQ feedback, a request to enable the HARQ feedback, a request to increase the number of the HARQ feedback, or a request to decrease the number of the HARQ feedback, and the at least one transceiver is further configured to transmit the upper-level parameters through an uplink channel. Claim 8 A base station (BS) comprises: a transceiver configured to transmit downlink control information (DCI) on a physical downlink control channel (PDCCH); and a processor operably connected to the transceiver, wherein the processor determines whether hybrid automatic repeat request (HARQ) feedback is disabled and is configured to generate the DCI having a first field indicating whether the HARQ feedback is disabled, and based on the first field indicating that the HARQ feedback is disabled, if the format of the DCI is a first format, the DCI includes a second field which is a reserved field and if the format of the DCI is a second format, the second field of the DCI has a width of 0 bits and the first format is one of DCI format 0_0 or DCI format 1_0 and the second format is one of DCI format 0_1 ​​or DCI format 1_1. Claim 9 In claim 8, the first field is either a dedicated field for indicating that the HARQ feedback is disabled using a reserved bit of the DCI format or an existing field of the DCI format, wherein the existing field can be interpreted as disabling the HARQ feedback, a base station (BS). Claim 10 delete Claim 11 delete Claim 12 In claim 8, a base station (BS), wherein when the DCI format is one of the DCI format 0_0 or the DCI format 0_1, the second field is one of the HARQ feedback number field or the TPC (transmit power control) command field for a scheduled physical uplink shared channel (PUSCH). Claim 13 In claim 8, where the DCI format is one of the DCI format 1_0 or the DCI format 1_1, the second field is one of the HARQ feedback number field, the transmit power control (TPC) command field for a scheduled physical uplink shared channel (PUSCH), the PUCCH resource indicator field, or the PDSCH-to-HARQ feedback timing indicator field, a base station (BS). Claim 14 In claim 8, the transceiver is further configured to receive upper-layer parameters through an uplink channel, wherein the upper-layer parameters include auxiliary information related to HARQ operation, and the auxiliary information includes at least one of soft buffer information for reception, a request to disable the HARQ feedback, a request to enable the HARQ feedback, a request to increase the number of the HARQ feedback, or a request to decrease the number of the HARQ feedback. Claim 15 A method performed by a user device (UE) in a wireless communication system, comprising: receiving downlink control information (DCI) in a physical downlink control channel (PDCCH); determining whether hybrid automatic repeat request (HARQ) feedback is disabled based on a first field of the DCI; and determining, based on the determination that the HARQ feedback is disabled, that if the format of the DCI is a first format, a second field of the DCI is a reserved field and if the format of the DCI is a second format, the second field of the DCI has a width of 0 bits, wherein the first format is one of DCI format 0_0 or DCI format 1_0, and the second format is one of DCI format 0_1 ​​or DCI format 1_1. Claim 16 In claim 15, the first field is either a dedicated field for indicating that the HARQ feedback is disabled using a reserved bit of the DCI format or an existing field of the DCI format, wherein the existing field is interpreted as disabling the HARQ feedback. Claim 17 delete Claim 18 In claim 15, where the DCI format is either DCI format 0_0 or DCI format 0_1, the second field is either a HARQ feedback number field or a transmit power control (TPC) command field for a scheduled physical uplink shared channel (PUSCH). Claim 19 In claim 15, where the DCI format is either the DCI format 1_0 or the DCI format 1_1, the second field is one of the HARQ feedback number field, the TPC (transmit power control) command field for the scheduled physical uplink shared channel (PUSCH), the PUCCH resource indicator field, or the PDSCH-to-HARQ feedback timing indicator field. Claim 20 The method of claim 15 further comprises the steps of: generating upper-layer parameters comprising auxiliary information related to HARQ operation—the auxiliary information comprising at least one of soft buffer information for reception, a request to disable the HARQ feedback, a request to enable the HARQ feedback, a request to increase the number of the HARQ feedback, or a request to decrease the number of the HARQ feedback—and transmitting the upper-layer parameters through an uplink channel.

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