Dual-root preamble design for delay and frequency shift

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may communicate with a base station by initiating a random access procedure utilizing a dual root preamble. The UE may receive control signaling indicating a root preamble sequence set from the base station. The UE may send a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set to the base station. The UE may then monitor a preamble response based on the preamble signal. In some cases, the base station may be a base station in a terrestrial network. In other cases, the base station may be a satellite in a non-terrestrial network (NTN).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 888,307, filed by Zhang et al. on August 16, 2019, entitled “Two-Root Preamble Design for Delay and FreqUEncy Shift”; and U.S. Patent Application No. 16 / 992,678, filed by Zhang et al. on August 13, 2020, entitled “Two-Root Preamble Design for Delay and FreqUEncy Shift”; each of which is assigned to its assignee. Background Art

[0003] The following relates generally to wireless communications and, more particularly, to a dual-preamble design for delay and frequency shift.

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth generation (4G) systems, such as long term evolution (LTE) systems, LTE advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems, which may be referred to as new radio (NR) systems. These systems may employ techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include multiple base stations or network access nodes, each of which simultaneously supports communication for multiple communication devices, which may be referred to as user equipment (UE).

[0005] The random access procedure between the UE and the base station may be initiated by the UE sending a random access channel (RACH) preamble to the base station. In some cases, the UE and the base station may be part of a non-terrestrial network (NTN). In these cases, there may be a large distance between the UE and the base station (e.g., a satellite). Due to the distance, there may be a long round trip delay (RTD) and frequency shift in the message transmission between the UE and the base station due to the Doppler shift effect. Summary of the invention

[0006] The described technology relates to an improved method, system, device and apparatus supporting a dual-root preamble design for delay and frequency shift. In general, the described technology is used for improved communications in non-terrestrial networks (NTNs), including detecting round-trip delay (RTD) and frequency shift associated with distance and relative speed in the NTN. The described technology provides a dual-root preamble design generated by a user equipment (UE) and sent to a satellite or base station as part of a random access process. The dual-root preamble enables the satellite to detect RTD and Doppler shift. The satellite can then send an indication of the RTD and Doppler shift to the UE, and in some examples, the UE can pre-compensate future transmissions based on the RTD and Doppler shift indications.

[0007] A method for wireless communication by a UE is described. The method may include: receiving control signaling indicating a root preamble sequence set; sending a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set; and monitoring a preamble response based on the preamble signal.

[0008] An apparatus for wireless communication by a UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to receive control signaling indicating a root preamble sequence set, send a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and monitor a preamble response based on the preamble signal.

[0009] Another apparatus for wireless communication by a UE is described. The apparatus may include components for receiving control signaling indicating a root preamble sequence set, transmitting a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and monitoring a preamble response based on the preamble signal.

[0010] A non-transitory computer-readable medium storing code for wireless communication by a UE is described. The code may include instructions executable by a processor to receive control signaling indicating a root preamble sequence set, send a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and monitor a preamble response based on the preamble signal.

[0011] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a preamble signal may include operations, features, components, or instructions for sending the preamble signal over two symbol periods that are consecutive in time.

[0012] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a preamble signal may include operations, features, components, or instructions for sending a first preamble signal generated based on a first root preamble sequence during a first symbol period and sending a second preamble signal generated based on a second root preamble sequence during a second symbol period, which second symbol period may be continuous in time with the first symbol period.

[0013] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, monitoring of a preamble response may include operations, features, components, or instructions for sending a second preamble signal based on determining that a preamble response may not have been received.

[0014] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, monitoring of a preamble response may include operations, features, components, or instructions for receiving a preamble response from a base station and establishing a connection with the base station based on the preamble response.

[0015] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a preamble signal may include operations, features, components, or instructions for sending a preamble signal that may be generated based on a first root preamble sequence pair including a first root preamble sequence and a second root preamble sequence.

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for generating a set of preamble code sequence pairs based on a root preamble code sequence set, wherein each first tuple of each preamble code sequence pair of the set of preamble code sequence pairs may be unique, and each second tuple of each preamble code sequence pair of the set of preamble code sequence pairs may be unique.

[0017] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for generating a set of preamble code sequence pairs based on a root preamble code sequence set, wherein each first tuple of each preamble code sequence pair of the set of preamble code sequence pairs may be unique, or each second tuple of each preamble code sequence pair of the set of preamble code sequence pairs may be unique.

[0018] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for receiving a Doppler indicator, a delay indicator, or both based on a preamble signal, and sending a data transmission, controlling a transmission, or both using a waveform that can be pre-compensated based on the Doppler indicator, the delay indicator, or both.

[0019] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for appending a first cyclic prefix to a first root preamble sequence and appending a second cyclic prefix to a second root preamble sequence to generate a combined root preamble sequence, wherein a preamble signal may be generated based on the combined preamble sequence.

[0020] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for appending a first cyclic prefix to a first root preamble sequence to generate a first appended preamble sequence and appending a second cyclic prefix to a second root preamble sequence to generate a second appended preamble sequence.

[0021] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a preamble signal may include operations, features, components, or instructions for sending a first preamble signal in a first frequency resource that may be generated based on a first additional preamble sequence and sending a second preamble signal in a second frequency resource that may be generated based on a second additional preamble sequence.

[0022] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first preamble signal and the second preamble signal may be sent during a single symbol period.

[0023] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a guard time satisfies a round trip delay threshold.

[0024] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a length of each of the first root preamble sequence and the second root preamble sequence satisfies a cyclic prefix length threshold.

[0025] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, each of the first root preamble sequence and the second root preamble sequence may be a Zadoff-Chu sequence.

[0026] A method of wireless communication by a wireless device is described. The method may include sending control signaling indicating a root preamble sequence set, receiving a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and sending a preamble response based on the preamble signal.

[0027] An apparatus for wireless communication via a wireless device is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to send control signaling indicating a root preamble sequence set, receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and send a preamble response based on the preamble signal.

[0028] Another apparatus for wireless communication by a wireless device is described. The apparatus may include components for sending control signaling indicating a root preamble sequence set, receiving a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and sending a preamble response based on the preamble signal.

[0029] A non-transitory computer-readable medium storing code for wireless communication via a wireless device is described. The code may include instructions executable by a processor to send control signaling indicating a root preamble sequence set, receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and send a preamble response based on the preamble signal.

[0030] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving a preamble signal may include operations, features, components, or instructions for receiving the preamble signal over two symbol periods consecutive in time via a transceiver.

[0031] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving a preamble signal may include operations, features, components, or instructions for receiving a first preamble signal generated based on a first root preamble sequence during a first symbol period and receiving a second preamble signal generated based on a second root preamble sequence during a second symbol period, which second symbol period may be continuous in time with the first symbol period.

[0032] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving a first preamble signal may include operations, features, components, or instructions for performing a first correlation of a first signal received during a first symbol period with each of the set of root preamble sequences to identify the first root preamble sequence, performing a second correlation of a second signal received during a second symbol period with each of the set of root preamble sequences to identify the second root preamble sequence, and identifying a Doppler shift, a delay, or both based on the first correlation, the second correlation, or both.

[0033] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for establishing a connection with a user device based on the preamble response.

[0034] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving a preamble signal may include operations, features, components, or instructions for receiving a preamble signal that may be generated based on a first root preamble sequence pair including a first root preamble sequence and a second root preamble sequence.

[0035] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for sending a Doppler indicator, a delay indicator, or both based on a preamble signal, and receiving a data transmission, controlling the transmission, or both using a waveform that can be pre-compensated based on the Doppler indicator, the delay indicator, or both.

[0036] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for sending a Doppler indicator, a delay indicator, or both based on a preamble signal, and demodulating a data transmission, controlling a transmission, or both based on the Doppler indicator, the delay indicator, or both.

[0037] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving a preamble signal may include operations, features, components, or instructions for receiving a first preamble signal in a first frequency resource and a second preamble signal in a second frequency resource.

[0038] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the first preamble signal and the second preamble signal may be sent during a single symbol period.

[0039] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a guard time satisfies a round trip delay threshold.

[0040] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, a length of each of the first root preamble sequence and the second root preamble sequence satisfies a cyclic prefix length threshold.

[0041] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, each of the first root preamble sequence and the second root preamble sequence may be a Zadoff-Chu sequence.

[0042] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the wireless device may be a ground base station or a satellite. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 An example of a wireless communication system supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown.

[0044] Figure 2 An example of a wireless communication system supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown.

[0045] Figure 3A and 3B An example of a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown.

[0046] Figure 4 An example of a preamble detection system supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown.

[0047] Figure 5 An example of a process flow supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown.

[0048] Figure 6 and 7 A block diagram of an apparatus supporting dual-root preamble design for delay and frequency shift according to aspects of the present invention is shown.

[0049] Figure 8 A block diagram of a communication manager supporting dual-root preamble design for delay and frequency shift is shown according to aspects of the present disclosure.

[0050] Fig. 9 A diagram of a system including a device supporting a dual-root preamble design for delay and frequency shift is shown according to aspects of the present disclosure.

[0051] Fig.10 and 11 A block diagram of an apparatus supporting dual-root preamble design for delay and frequency shift according to aspects of the present invention is shown.

[0052] Fig.12 A block diagram of a communication manager supporting dual-root preamble design for delay and frequency shift is shown according to aspects of the present disclosure.

[0053] Fig.13 A diagram of a system including a device supporting a dual-root preamble design for delay and frequency shift is shown according to aspects of the present disclosure.

[0054] Figures 14 to 17 A flow chart of a method supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0055] A non-terrestrial network (NTN) may be a wireless communication system that involves the use of satellites to provide coverage for ground base stations and user equipment (UE). One or more satellites may be included in an NTN. Some satellites in an NTN may be used as base stations, and the UE may communicate directly with the serving satellite. In other cases, the base station or other satellites may relay transmissions between the serving satellite and the UE.

[0056] Satellite may refer to a vehicle that operates in various Earth orbits, particularly at distances from the Earth's surface. For example, a satellite may operate in a low Earth orbit (LEO), a medium Earth orbit (MEO), a geostationary orbit (GEO), a geosynchronous orbit (GSO), a highly elliptical orbit (HEO), or other types of orbits. Each type of orbit may be defined by a range of distances from the Earth's surface. The distance between a UE and a serving satellite may be much greater than the typical distance between a UE and a base station in a terrestrial network.

[0057] The distance between the satellite and the UE may cause round trip delay (RTD) and frequency shift, which may negatively affect the efficiency and communication function between the UE and the satellite. The frequency shift in the communication frequency between the satellite and the UE may be caused by Doppler shift and local oscillator errors. For example, a satellite may be 600 kilometers from the surface of the earth. The satellite may have a small cell diameter of 100 kilometers and may observe frequency shifts of up to 125 kilohertz (kHz).

[0058] The UE may determine to connect to a new cell or base station (such as a satellite) based on various communication parameters, the movement of the UE, or the initiation of a handover procedure. To initiate communication with a different cell, the UE may send a random access channel (RACH) preamble to begin a random access procedure to connect to the new cell. The transmission of the preamble may occur in a physical random access channel (PRACH), and the preamble may be transmitted as part of a multi-step random access procedure.

[0059] The random access procedure for a UE connected to a cell may include multiple steps. The UE may send a preamble message (e.g., PRACH Msg1) to a base station (e.g., a satellite). The base station may send a preamble response (e.g., PRACH response Msg2) based on the received preamble. Based on receiving the preamble response, the UE may send a radio resource control (RRC) connection request (e.g., Msg3) to the base station. The base station may respond with an RRC connection establishment message (e.g., Msg4). Each of these messages may be transmitted back and forth between the UE and the base station. In terrestrial networks, RTD may have a smaller impact on message delivery delay, and Doppler shift and frequency may also have a smaller impact.

[0060] However, in the case where the base station is an orbiting satellite, the RTD and frequency shifts caused by the long-range aspect of the NTN may hinder the transmission timing of the random access procedure transmission. This may affect and interfere with the transmission of the random access procedure between the satellite and the UE, as well as the transmission of other messages transmitted after the UE is connected to the cell. In addition, the frequency shift caused by the Doppler effect associated with the NTN may affect accurate message reception and may result in inaccurate decoded messages and inefficient transmissions.

[0061] In some cases, the design of the preamble (e.g., the NR PRACH preamble) may not include the ability of the receiving base station or satellite to accommodate large (differential) RTDs or large frequency shifts due to the Doppler effect, and may not include the ability to estimate the RTD or frequency shift. For example, these preambles may support RTDs up to 684 microseconds (μs) and frequency shifts up to 10 kilohertz (kHz) within a cell. These limitations may be much smaller than the differential RTD and frequency shift of NTN.

[0062] These preambles may include a Zadoff-Chu (ZC) root plus a cyclic shift. With this preamble design, in order to be able to identify RTD and frequency shift (e.g., due to Doppler effect), the cyclic shift needs to be large enough to contain the shift caused by both RTD and frequency shift. This may also assume that the RTD is smaller than the cyclic shift and the frequency shift is less than 1 or 2 times the subcarrier spacing (SCS). The RTD and frequency shift associated with NTN may not meet these requirements for cyclic shift and preamble for certain types of preambles, such as in NR systems.

[0063] In the case where the RTD and frequency shift are large due to the transmission distance in the NTN, the UE can instead generate a preamble using a ZC sequence and orthogonal frequency division multiplexing (OFDM) modulation without using cyclic shift. This dual-root preamble can support communications in networks with larger frequency shifts and longer RTDs. For example, some preambles can support a frequency shift range of ±500kHz and an RTD range up to the minimum value of the cyclic prefix (CP) and the guard time (GT) (e.g., min(CP, GT)).

[0064] Various aspects of the present invention are initially described in the context of wireless communication systems. Aspects of the present invention are further described with respect to preamble design, preamble detection systems, and process flows. Various aspects of the present invention are further illustrated and described by apparatus diagrams, system diagrams, and flow diagrams related to dual-root preamble design for delay and frequency shift.

[0065] Figure 1An example of a wireless communication system 100 supporting a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. The wireless communication system 100 includes a base station 105, a UE 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an LTE advanced (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some cases, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

[0066] The base station 105 may communicate wirelessly with the UE 115 via one or more base station antennas. The base station 105 described herein may include or may be referred to by those skilled in the art as a base transceiver, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next generation NodeB or a giga-NodeB (any of which may be referred to as a gNB), a home NodeB, a home eNodeB, or other suitable terms. The wireless communication system 100 may include different types of base stations 105 (e.g., macro or small cell base stations). The UE 115 described herein may be able to communicate with various types of base stations 105 and network devices including macro eNBs, small cell eNBs, gNBs, relay base stations, etc.

[0067] Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 are supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via a communication link 125, and the communication link 125 between the base station 105 and the UE 115 may utilize one or more carriers. The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. Downlink transmissions may also be referred to as forward link transmissions, and uplink transmissions may also be referred to as reverse link transmissions.

[0068] The geographic coverage area 110 of the base station 105 may be divided into sectors that constitute a portion of the geographic coverage area 110, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for a macro cell, a small cell, a hotspot, or other type of cell, or various combinations thereof. In some examples, the base station 105 may be mobile, thereby providing communication coverage for a mobile geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous LTE / LTE-A / LTE-A Pro or NR network, in which different types of base stations 105 provide coverage for various geographic coverage areas 110.

[0069] The term "cell" refers to a logical communication entity for communicating with a base station 105 (e.g., via a carrier), and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID)) for distinguishing adjacent cells operating via the same or different carriers. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types that may provide access to different types of devices (e.g., machine type communication (MTC), narrowband Internet of Things (NB-IoT), enhanced mobile broadband (eMBB), or other). In some cases, the term "cell" may refer to a portion of a geographic coverage area 110 (e.g., a sector) on which the logical entity operates.

[0070] UE 115 can be dispersed throughout the wireless communication system 100, and each UE 115 can be fixed or mobile. UE 115 can also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where "device" can also be referred to as a unit, a station, a terminal, or a client. UE 115 can also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 can also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, etc., which can be implemented in various items such as devices, vehicles, meters, etc.

[0071] Some UEs 115, such as MTC or IoT devices, may be low-cost or low-complexity devices and may provide automatic communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technology that allows devices to communicate with each other or with a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application that may utilize or present the information to a person interacting with the program or application. Some UEs 115 may be designed to collect information or implement automatic behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, medical monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business billing.

[0072] Some UEs 115 may be configured to employ a reduced power consumption mode of operation, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception but not simultaneous transmission and reception). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power saving techniques for UE 115 include entering a power saving "deep sleep" mode when not engaged in active communications or operating over limited bandwidth (e.g., in accordance with narrowband communications). In some cases, UE 115 may be designed to support critical functions (e.g., mission critical functions), and the wireless communication system 100 may be configured to provide ultra-reliable communications for these functions.

[0073] In some cases, UE 115 may also communicate directly with other UE 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol). One or more of a group of UEs 115 utilizing D2D communication may be within a geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105, or otherwise unable to receive transmissions from the base station 105. In some cases, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system, in which each UE 115 transmits to each other UE 115 in the group. In some cases, the base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs 115 without involving the base station 105.

[0074] The base stations 105 may communicate with the core network 130 or with each other. For example, the base stations 105 may interface with the core network 130 via a backhaul link 132 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 may communicate with each other directly (e.g., directly between the base stations 105) or indirectly (e.g., via the core network 130) via a backhaul link 134 (e.g., via X2, Xn, or other interfaces).

[0075] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC), which may include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management of UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transmitted via the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation and other functions. The P-GW may be connected to network operator IP services. Operator IP services may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or packet switched (PS) streaming services.

[0076] At least some network devices (such as base stations 105) may include subcomponents, such as access network entities, which may be examples of access node controllers (ANCs). Each access network entity may communicate with UE 115 through multiple other access network transport entities, which may be referred to as radio heads, smart radio heads, or transmit / receive points (TRPs). In some configurations, the various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or merged into a single network device (e.g., base station 105).

[0077] The wireless communication system 100 can operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Typically, the region from 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or decimeter wave band because the wavelength range is approximately 1 decimeter to 1 meter long. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves can penetrate the structure sufficiently so that the macrocell provides service to the UE 115 located indoors. Compared to transmissions using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz, transmissions using UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 km).

[0078] The wireless communication system 100 may also operate in the Super High Frequency (SHF) region using a frequency band from 3 GHz to 30 GHz (also referred to as a centimeter wave band). The SHF region includes frequency bands such as the 5 GHz Industrial, Scientific, and Medical (ISM) band, which may be opportunistically used by devices that can tolerate interference from other users.

[0079] The wireless communication system 100 may also operate in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), also referred to as the millimeter wave band. In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antennas of each device may be smaller and closer together than the UHF antennas. In some cases, this may facilitate the use of antenna arrays within the UE 115. However, the propagation of EHF transmissions may be affected by greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The technology disclosed herein may be used across transmissions using one or more different frequency regions, and the designated use of frequency bands across these frequency regions may vary by country or regulatory agency.

[0080] In some cases, the wireless communication system 100 can use licensed and unlicensed radio spectrum bands. For example, the wireless communication system 100 can adopt license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5GHz ISM band. When operating in an unlicensed radio spectrum band, wireless devices such as base stations 105 and UE 115 can adopt a listen-before-talk (LBT) process to ensure that the channel is clear before sending data. In some cases, operations in unlicensed bands can be based on carrier aggregation configurations and component carriers (e.g., LAA) operating in licensed bands. Operations in unlicensed spectrum can include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum can be based on frequency division duplexing (FDD), time division duplexing (TDD), or a combination of both.

[0081] In some examples, the base station 105 or the UE 115 may be equipped with multiple antennas, which can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. For example, the wireless communication system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115), wherein the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communication may employ multipath signal propagation to improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. For example, multiple signals may be transmitted by a transmitting device via different antennas or different combinations of antennas. Similarly, multiple signals may be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO), where multiple spatial layers are sent to the same receiving device, and multi-user MIMO (MU-MIMO), where multiple spatial layers are sent to multiple devices.

[0082] Beamforming, also known as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals communicated via antenna elements of an antenna array so that signals propagating in a particular direction relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals communicated via antenna elements may include a transmitting device or a receiving device that applies amplitude and phase offsets to signals carried via each antenna element associated with the device. The adjustments associated with each antenna element may be defined by a set of beamforming weights associated with a particular direction (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other direction).

[0083] In one example, the base station 105 may use multiple antennas or antenna arrays to perform beamforming operations for directional communication with the UE 115. For example, some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be sent multiple times by the base station 105 in different directions, which may include signals sent according to different beamforming weight sets associated with different transmission directions. The transmissions in different beam directions may be used (e.g., by the base station 105 or a receiving device, such as the UE 115) to identify the beam direction for subsequent transmission or reception, or both, by the base station 105.

[0084] Some signals, such as data signals associated with a particular receiving device, may be transmitted by base station 105 in a single beam direction (e.g., a direction associated with a receiving device such as UE 115). In some examples, a beam direction associated with transmissions along a single beam direction may be determined based at least in part on signals transmitted in different beam directions. For example, UE 115 may receive one or more signals transmitted by base station 105 in different directions, and UE 115 may report to base station 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality. Although these techniques are described with reference to signals transmitted by base station 105 in one or more directions, UE 115 may employ similar techniques to transmit signals multiple times in different directions (e.g., to identify a beam direction for subsequent transmission or reception by UE 115), or to transmit signals in a single direction (e.g., to transmit data to a receiving device).

[0085] A receiving device (e.g., UE 115, which may be an example of a mmW receiving device) may attempt multiple receive beams when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from base station 105. For example, the receiving device may attempt multiple receive directions by receiving via different antenna subarrays, by processing the received signal according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, or by processing the received signal according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array (any of which may be referred to as "listening" according to different receive beams or receive directions). In some examples, the receiving device may receive along a single beam direction using a single receive beam (e.g., when receiving a data signal). The single receive beam may be aligned in a beam direction determined at least in part based on listening according to different receive beam directions (e.g., a beam direction with the highest signal strength, highest signal-to-noise ratio, or other acceptable signal quality determined at least in part based on listening according to multiple beam directions).

[0086] In some cases, the antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays that may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, the antennas or antenna arrays associated with a base station 105 may be located at different geographic locations. A base station 105 may have an antenna array with multiple rows and columns of antenna ports that the base station 105 may use to support beamforming for communications with a UE 115. Similarly, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

[0087] In some cases, the wireless communication system 100 can be a packet-based network operating according to a layered protocol stack. In the user plane, the communication of the bearer or packet data convergence protocol (PDCP) layer can be based on IP. The radio link control (RLC) layer can perform packet segmentation and reassembly to communicate through logical channels. The medium access control (MAC) layer can perform priority processing and multiplexing of logical channels to transport channels. The MAC layer can also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer can provide the establishment, configuration and maintenance of the RRC connection between the UE 115 and the base station 105 or the core network 130 supporting the radio bearer for user plane data. At the physical layer, the transport channel can be mapped to the physical channel.

[0088] In some cases, UE 115 and base station 105 may support retransmission of data to increase the possibility of successfully receiving data. HARQ feedback is a technique to increase the possibility of correctly receiving data through communication link 125. HARQ may include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC) and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput of the MAC layer under poor radio conditions (e.g., signal-to-noise ratio conditions). In some cases, a wireless device may support same-slot HARQ feedback, wherein the device may provide HARQ feedback in a specific time slot for data received in a previous symbol in the time slot. In other cases, the device may provide HARQ feedback in a subsequent time slot or according to some other time intervals.

[0089] Time intervals in LTE or NR can be expressed as multiples of a basic time unit. For example, a basic time unit can refer to T s = 1 / 30,720,000 second sampling period. The time interval of the communication resource can be organized according to a radio frame each having a duration of 10 milliseconds (ms), where the frame period can be represented as Tf =307,200T s . A radio frame may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots, each slot having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix preceding each symbol period). In addition to the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In other cases, the smallest scheduling unit of the wireless communication system 100 may be shorter than a subframe, or may be dynamically selected (e.g., in a burst of a short TTI (sTTI), or in a selected component carrier using sTTI).

[0090] In some wireless communication systems, a time slot may be further divided into a plurality of mini-slots containing one or more symbols. In some cases, a symbol of a mini-slot or a small-slot may be the smallest scheduling unit. For example, the duration of each symbol may be different depending on the subcarrier spacing or the operating frequency band. In addition, some wireless communication systems may implement time slot aggregation, where multiple time slots or mini-slots are aggregated together and used for communication between UE 115 and base station 105.

[0091] The term "carrier" refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications on the communication link 125. For example, a carrier of the communication link 125 may include a portion of a radio frequency band that operates according to a physical layer channel of a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a predefined frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be located according to a channel raster for discovery by a UE 115. A carrier may be downlink or uplink (e.g., in FDD mode), or may be configured to carry downlink and uplink communications (e.g., in TDD mode). In some examples, a signal waveform transmitted by a carrier may be composed of multiple subcarriers (e.g., using a multi-carrier modulation (MCM) technique such as OFDM or discrete Fourier transform spread OFDM (DFT-S-OFDM)).

[0092] The organization structure of the carrier can be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR). For example, communications on a carrier can be organized based on TTIs or time slots, each of which can include user data and control information or signaling to support decoding of the user data. The carrier can also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc.) and control signaling to coordinate the operation of the carrier. In some examples (e.g., in a carrier aggregation configuration), the carrier can also have acquisition signaling or control signaling to coordinate the operation of other carriers.

[0093] Physical channels may be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed on a downlink carrier, for example, using a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique. In some examples, control information transmitted in a physical control channel may be distributed in a cascaded manner between different control regions (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces).

[0094] A carrier may be associated with a particular bandwidth of the radio spectrum, and in some examples, the carrier bandwidth may be referred to as the "system bandwidth" of the carrier or wireless communication system 100. For example, the carrier bandwidth may be one of a plurality of predetermined bandwidths (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) of a carrier for a particular radio access technology. In some examples, each serviced UE 115 may be configured to operate on part or all of the carrier bandwidth. In other examples, some UEs 115 may be configured to operate using a narrowband protocol type associated with a predefined portion or range (e.g., a set of subcarriers or RBs) within a carrier (e.g., an "in-band" deployment of a narrowband protocol type).

[0095] In a system using MCM technology, a resource element may include a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol period and the subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme). Therefore, the more resource elements received by UE 115 and the higher the order of the modulation scheme, the higher the data rate of UE 115 may be. In a MIMO system, wireless communication resources may refer to a combination of radio spectrum resources, time resources, and space resources (e.g., space layers), and the use of multiple space layers may further increase the data rate of communication with UE 115.

[0096] A device of the wireless communication system 100 (e.g., a base station 105 or a UE 115) may have a hardware configuration that supports communication on a specific carrier bandwidth, or may be configured to support communication on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 and a UE 115 that support simultaneous communication via carriers associated with more than one different carrier bandwidth.

[0097] The wireless communication system 100 may support communication with the UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, the UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used with both FDD and TDD component carriers.

[0098] In some cases, the wireless communication system 100 can utilize an enhanced component carrier (eCC). An eCC can be characterized by one or more characteristics, including a wider carrier or frequency channel bandwidth, a shorter symbol duration, a shorter TTI duration, or a modified control channel configuration. In some cases, an eCC can be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have suboptimal or non-ideal backhaul links). An eCC can also be configured for use in an unlicensed spectrum or a shared spectrum (e.g., where more than one operator is allowed to use the spectrum). An eCC characterized by a wide carrier bandwidth can include one or more segments that can be used by UEs 115 that cannot monitor the entire carrier bandwidth or are configured to use a limited carrier bandwidth (e.g., to save power).

[0099] In some cases, an eCC may use a different symbol duration than other component carriers, which may include using a reduced symbol duration compared to the symbol duration of other component carriers. A shorter symbol duration may be associated with an increased spacing between adjacent subcarriers. A device such as a UE 115 or a base station 105 utilizing an eCC may transmit a wideband signal (e.g., according to a frequency channel or carrier bandwidth of 20, 40, 60, 80 MHz, etc.) with a reduced symbol duration (e.g., 16.67 microseconds). A TTI in an eCC may consist of one or more symbol periods. In some cases, the TTI duration (i.e., the number of symbol periods in a TTI) may be variable.

[0100] The wireless communication system 100 may be an NR system that may utilize any combination of licensed, shared, and unlicensed bands, etc. The flexibility of eCC symbol duration and subcarrier spacing allows the use of eCC across multiple spectrums. In some examples, NR shared spectrum may improve spectrum utilization and spectrum efficiency, specifically through dynamic vertical (e.g., across frequency domain) and horizontal (e.g., across time domain) resource sharing.

[0101] The wireless communication system 100 includes a base station 105, a user terminal 115, a satellite 120, and a core network 130. In some examples, the wireless communication system 100 may be an LTE network, an LTE-A network, an LTE-A Pro network, or an NR network. In some cases, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

[0102] The wireless communication system 100 may also include one or more satellites 120. The satellites 120 may communicate with the base stations 105 and the user terminals 115 (such as UEs). The satellites 120 may be any suitable type of communication satellite configured to relay communications between different terminal nodes in the wireless communication system. The satellites 120 may be examples of space satellites, balloons, spacecraft, aircraft, drones, unmanned aerial vehicles, etc. In some examples, the satellites 120 may be in geosynchronous or geostationary earth orbits, low earth orbits, or medium earth orbits. The satellites 120 may be multi-beam satellites configured to provide services for multiple service beam coverage areas in a predefined geographic service area. The satellites 120 may be at any distance from the surface of the earth.

[0103] In some cases, the cell can be provided or established by the satellite 120 as part of a non-terrestrial network. In some cases, the satellite 120 can perform the functions of the base station 105, act as a bent pipe satellite, or can act as a regenerative satellite, or a combination thereof. In other cases, the satellite 120 can be an example of an intelligent satellite or a satellite with intelligence. For example, an intelligent satellite can be configured to perform more functions than a regenerative satellite (for example, it can be configured to execute specific algorithms other than the algorithms used in the regenerative satellite for reprogramming, etc.). The bent pipe transponder or satellite can be configured to receive signals from a ground station and send these signals to different ground stations. In some cases, the bent pipe transponder or satellite may amplify the signal or switch from an uplink frequency to a downlink frequency. The regenerative transponder or satellite can be configured to relay signals, such as a bent pipe transponder or satellite, but other functions can also be performed using on-board processing. Examples of these other functions may include demodulating received signals, decoding received signals, recoding signals to be sent, or modulating signals to be sent, or a combination thereof. For example, a bent pipe satellite (eg, satellite 120) may receive a signal from base station 105 and may relay the signal to user terminal 115 or base station 105, or vice versa.

[0104] UE 115 may communicate with satellite 120 using communication link 125. UE 115 may utilize a random access procedure including a preamble transmission to gain communication access with satellite 120. Satellite 120 may orbit the earth, and communications between UE 115 and satellite 120 may be associated with long RTD and frequency shift. UE 115 may generate and transmit a dual-root preamble for detecting RTD and frequency shift.

[0105] Figure 2 An example of a wireless communication system 200 that supports dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. In some examples, the wireless communication system 200 can implement aspects of the wireless communication system 100. The wireless communication system 200 can include a base station 105-a, a UE 115-a, and a satellite 120-a, which can be as described in reference Figure 1 1. Examples of base stations 105, UEs 115, and satellites 120. In the case of a terrestrial network, base station 105-a may serve coverage area 110-a, and in the case of an NTN, satellite 120-a may serve coverage area 110-a. UE 115-a may communicate with satellite 120-a by sending signaling in transmission channel 205, and UE 115-a may communicate with base station 105-a by sending signaling in transmission channel 210.

[0106] UE 115 may communicate with base station 105 and satellite 120 as part of wireless communications in the NTN. For example, UE 115-a may communicate with satellite 120-a via communication link 205. In the case of a terrestrial network, UE 115-a may communicate with base station 105-a via communication link 210. In the case of NTN wireless communications, satellite 120-a may be a serving base station for UE 115-a.

[0107] Satellite 120-a may orbit the surface of the earth at a certain altitude. The distance between satellite 120-a and UE 115-a may be much greater than the distance between base station 105-a and UE 115-a. The distance between UE 115-a and satellite 120-a may cause an increase in RTD in the communication between UE 115-a and satellite 120-a. The distance may also cause a frequency shift in the communication between UE 115-a and satellite 120-a. The frequency shift may be caused by the Doppler effect and errors associated with the local oscillation of UE 115-a or satellite 120-a. The RTD and frequency shift associated with communication in NTN may result in low transmission efficiency, latency, and inability to accurately send and receive messages.

[0108] UE 115-a may determine to connect to satellite 120-a using a random access procedure (e.g., a four-step RACH). Initiation of the RACH procedure may begin with UE 115-a sending a random access preamble 220 (e.g., NR PRACH) to UE 115-a via communication link 205-a. UE 115-a may send the random access preamble in a PRACH. In some PRACH designs, the RTD or frequency shift associated with the NTN may not be estimated or accounted for.

[0109] In order to estimate the RTD and frequency shift associated with communicating with the orbiting satellite 120-a in the NTN, the UE 115-a may initiate a random access procedure using a dual-root preamble to connect to the satellite 120-a. The dual-root preamble may be based on control signaling 215 sent by the satellite 120-a over the communication link 205-a. The control signaling 215 may include information related to possible ZC roots and sequences used by the UE 115-a to generate the preamble. In some cases, the control signaling 215 may include a set of ZC roots and sequences, or in other cases, the set of sequences may be preconfigured at the UE 115-a. In these cases, the control signaling may include a bit to instruct the UE 115-a to select a root for the dual-root preamble.

[0110] The dual-root preamble may include two ZC sequences. Each of the two ZC sequences may include a different root. The root may be labeled μ n For example, the roots of two ZC sequences may be defined as μ0 and μ1, where μ0≠μ1. A dual-root preamble as described herein may not include a cyclic shift allocation in some cases. Instead, each root pair may have a zero shift.

[0111] The dual-root preamble sequence length may be greater than the CP (e.g., sequence length>cyclic prefix), and the guard period (GP) may exceed the RTD. The GP plus the CP of the preamble may be configured to be greater than the RTD between the UE 115 and the satellite 120. In addition, the sequence length multiplied by the SCS of the communication channel between the UE 115 and the satellite 120 may be configured to be greater than 2 times the maximum value of the frequency shift amplitude. Therefore, the sequence length of the dual-root preamble sequence may satisfy the following equation:

[0112] sequence length ×SCS>2×max|Fd| (1)

[0113] where maxFd is the frequency shift caused by the distance between UE 115 and satellite 120.

[0114] For example, the preamble may have a sequence length of 839 (eg, Len-839) and may operate in a system with an SCS of 1.25 kHz. The preamble sequence length may be inserted into Equation 1 as follows:

[0115] ±839×1.25>2×maxFd (2)

[0116] Therefore, the preamble sequence (Len-839) can mitigate frequency shifts up to ±524kHz.

[0117] A specific preamble may be selected based on the generation of a preamble set. In some cases, a specific radio access technology (RAT) may have a specific preamble set size P (e.g., P=64 in NR). Based on this set size P, P pairs (μ) of ZC roots may be generated. 0j ,μ 1j ), so that j = 0, 1, ..., P-1. We can further generate pairs so that for j ≠ j ′, μ 0j ≠μ 0j′ And μ 1j ≠μ 1j′ In another example, for a preamble set size P, P pairs (μ 0j ,μ 1j ),j=0,1,...,P-1, so that for j≠j′, μ 0j ≠μ 0j′ or μ 1j ≠μ 1j′ In the second case, in some cases, at most q pairs (eg, q=2) have the same first root, and at most q pairs have the same second root.

[0118] UE 115-a may randomly select a pair of ZC roots from a set of possible ZC root pairs. The set of possible ZC root pairs may be signaled to UE 115-a in control signaling 215 from satellite 120-a. Based on selecting a pair of ZC roots, UE 115-a may generate a complete preamble sequence including a CP. In some cases, the sequence corresponding to each ZC root may be modulated into a different OFDM symbol with a corresponding CP, and in some cases, the sequence corresponding to each ZC root may be modulated into the same OFDM symbol with one leading CP.

[0119] The UE 115-a may send a dual preamble signal 220 to the satellite 120-a to initiate a random access procedure. The satellite 120-a may receive the preamble signal and may determine the RTD and the Doppler shift based on the preamble signal 220. The satellite 120-a may send a preamble response 225 to the UE 115-a to continue the random access procedure between the UE 115-a and the satellite 120-a.

[0120] In some cases, multiple UEs 115 within a coverage area or connected to the same serving base station 105 or satellite 120 may select the same root pair for a preamble. In this case, there may be a collision between preamble transmissions of two UEs 115 that selected the same ZC root pair. This may result in a transmission failure, and the UE 115 may not receive a preamble response from the satellite 120 to which the UE 115 sent the preamble. In some cases, the UE 115-a may retransmit the same preamble, or generate and send a new preamble based on a different ZC root pair.

[0121] In some cases, the UE 115-a may send a dual-root preamble to the terrestrial base station 105-a via the communication link 210 to initiate a random access procedure with the base station 105-a rather than with the non-terrestrial satellite 120-a. This may include the base station 105-a determining the RTD and Doppler shift based on the dual-root preamble received from the UE 115-a. The base station 105-a may then send a preamble response to the UE 115-a to continue the RACH procedure.

[0122] Figure 3A An example of a dual-root preamble design 301 for delay and frequency shift according to aspects of the present disclosure is shown. In some examples, the preamble design 301 can implement aspects of the wireless communication system 100. As shown in FIG. Figure 2 As described above, the preamble generated according to the preamble design 301 may be sent by the UE 115 to the satellite 120 or the base station 105. The preamble 305-a may be an example of one possible preamble generated based on the first ZC root pair selection. The preamble 305-b may be an example of another possible preamble generated based on the second ZC root pair selection. Based on the number of other possible ZC root pair selections, there may be more possible preambles 305. The preamble design 301 may result in a longer symbol length and a lower peak-to-average power ratio (PAPR).

[0123] Based on the generation of the preamble set and the selection of the ZC root pair, the UE 115 may generate a random access preamble 305. The UE 115 may generate a plurality of different preambles based on the selected ZC root pair. Figure 2The ZC root pair is selected. In some cases, the UE 115 may generate a first preamble 305-a, a second preamble 305-b, or subsequent preambles (e.g., up to 64 preambles in the case of 5G NR). The UE 115 may select a pair of ZC root preamble sequences from a set of ZC preamble sequences (e.g., broadcast by the base station 105, or the UE is preconfigured therewith, etc.) to generate two preamble sequences (e.g., SEQ00 and SEQ01) of the preamble 305. The UE 115 may also copy a portion of the end of the preamble sequence (e.g., SEQ00) and place the copied portion (e.g., CP00) at the beginning of the preamble sequence to generate the preamble 305, so that the detection of the preamble by the base station or satellite may overlap with the end of the CP and still detect the entire preamble sequence.

[0124] For example, CP00 310-a and a sequence (e.g., SEQ00) may correspond to one of two ZC root pairs selected for the preamble. SEQ00 may be modulated into an OFDM symbol 315-a of length 320-a. A second selected ZC root pair may correspond to a second CP00 310-b and a second sequence SEQ01. SEQ01 may be modulated into a second OFDM symbol 315-b.

[0125] Subsequently, two OFDM symbols 315 may be connected back-to-back, including corresponding CP 310. Therefore, the full random access preamble 305-a may sequentially include CP00 310-a, SEQ00 in OFDM symbol 315-a, then CP01 310-b, and SEQ01 in OFDM symbol 315-b.

[0126] Another preamble 305 - b may be similarly generated, where CP10 310 - c and SEQ10 are modulated into one OFDM symbol 315 - c , concatenated back-to-back with a second CP11 310 - d and SEQ11 , where SEQ11 is modulated into a second OFDM symbol 315 - d .

[0127] The preamble 305-b may be offset from the preamble 305-a by a guard period (GP) 320-c. The GP 320-c may be less than or equal to the RTD of the communication between the UE 115 and the satellite 120 (or base station 105). The end of the preamble 305-a and the end of the preamble 305-b may also be separated by the GP 320-b. The GP 320-b may also be less than or equal to the RTD. One or more preambles 305 may be generated similarly, and thus the preamble design 301 may be applied to generate a desired number of preambles 305. The UE 115 may select one of the preambles 305 (e.g., 305-a), generate a preamble signal using the selected preamble 305-a, and send the preamble signal during a random access procedure (e.g., a RACH procedure).

[0128] Figure 3B An example of a dual-root preamble design 302 for delay and frequency shift according to aspects of the present disclosure is shown. Figure 2 As described above, the preamble generated according to the preamble design 302 may be sent by the UE 115 to the satellite 120 or the base station 105. The preamble 305-c may be an example of one possible preamble generated based on the first ZC root pair selection. The preamble 305-d may be an example of another possible preamble generated based on the ZC root pair selected by the UE 115. There may be more possible preambles 305 based on the number of other possible ZC root pairs.

[0129] The preamble design 302 may generate a shorter symbol than the preamble design 301 at the expense of a high PAPR. The UE 115 may generate a first preamble 305-c, a second preamble 305-d, or subsequent preambles (e.g., up to 64 preambles in the case of 5G NR). The UE 115 may select a pair of ZC preamble sequence roots from a set of ZC root preamble sequences (e.g., broadcast by the base station 105, or the UE is preconfigured therewith, etc.) to generate a pair of preamble sequences (e.g., SEQ10 and SEQ11). The UE 115 may also copy a portion of the end of the preamble sequence (e.g., SEQ00) and place the copied portion (e.g., CP00) at the beginning of the preamble sequence to generate the preamble 305, so that the detection of the preamble by the base station or satellite may overlap with the end of the CP and still detect the entire preamble sequence.

[0130] The preamble 305 in the preamble design 302 may be generated using a different modulation scheme than the preamble described in the preamble design 301. In this case, the preamble 305-c may be generated by the UE 115. The two sequences corresponding to the two selected ZC roots may be modulated into a single OFDM symbol 315 (e.g., on different subcarriers). For example, SEQ00 may be associated with the first ZC root and SEQ01 may be associated with the second ZC root. SEQ00 and SEQ01 may be DFT transformed to the same or different frequency bands (e.g., on adjacent or non-adjacent subcarriers) and then modulated into a single OFDM symbol 315-e. The generation of the preamble 305-c may include CP0 310-e added to the beginning of the OFDM symbol 315-e.

[0131] The second preamble, preamble 305-d, may be generated in a similar manner to preamble 305-c. However, preamble 305-d may include GP 320-f, which separates the start of CP1 310-f from the start of CP0 310-e and their corresponding time sequence. For preamble 305-d, two sequences, SEQ10 and SEQ11, may be generated based on two different ZC roots. The two sequences SEQ10 and SEQ11 may be DFT-transformed to the same or different frequency bands and may then be modulated into a single OFDM symbol 315-e. One or more preambles 305 may be generated similarly, and thus preamble design 302 may be applied to generate a desired number of preambles 305. UE 115 may select one of preambles 305 (e.g., 305-c), generate a preamble signal using the selected preamble 305-a, and transmit the preamble signal during a random access procedure (e.g., a RACH procedure).

[0132] Figure 4 An example of a preamble detection system 400 supporting a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. In some examples, the preamble detection system 400 can implement aspects of the wireless communication system 100. The UE 115 can generate a preamble 405-A according to the preamble design 301. Alternatively or in addition, the UE 115 can generate a preamble 405-b according to the preamble design 302. The UE 115 can send the preamble 405 to the satellite 120. The satellite 120 can cut a fast Fourier transform (FFT) window 420 (e.g., using multiple FFT windows) to detect the root pair sequence in the preamble, or if the preamble is multiplexed in frequency, a single FFT window can be applied.

[0133] Based on reference Figure 3A and 3BThe generated preamble 305 (eg, preamble 305 - a or 305 - b ) may be sent by the UE 115 to the base station 105 or the satellite 120 to initiate a PRACH process. In the NTN, the satellite 120 may detect the preamble 405 received from the UE 115 .

[0134] In some cases, UE 115 may generate preamble 405-a corresponding to preamble design 301. In other cases, UE 115 may generate preamble 405-b corresponding to preamble design 302. Either preamble 405-a or 405-b may include two sequences generated based on a selected ZC root of a plurality of possible ZC roots.

[0135] To detect the preamble 405-a, the satellite 120 may clip the FFT window 420 to detect individual sequences of the preamble (e.g., SEQ00 and SEQ01 in the OFDM symbol 415). For example, the UE 115 may send the random access preamble 405-a to the satellite 120. The satellite 120 may clip the FFT window 420-a to detect the first root sequence SEQ00 in the OFDM symbol 415-a. The satellite 120 may also clip the FFT window 420-b to detect the second root sequence SEQ01 in the OFDM symbol 415-b. In some cases, the FFT window may cover the end of the CP instead of the end of the preamble. When generating the preamble, appending the end of the sequence to the end of the CP accommodates this and ensures that the preamble is still fully detected.

[0136] The satellite 120 may detect the selected ZC root. The ZC root may be defined as μ0 and μ1 for SEQ00 and SEQ01, respectively. The satellite 120 may detect the root based on identifying a correlation peak 430. Because the ZC pairs used to generate the preamble sequence may be orthogonal, the correlation peak 430 may be detected when the preamble sequence is correlated with the root used to generate the preamble sequence. When different roots are used, the amplitude output by the correlation process may not include a correlation peak (e.g., having an amplitude similar to other roots), so the base station or satellite may determine that the root is not detected when a correlation peak is not found. The base station 105 or satellite 120 may check each root in the root set announced to the UE 115 until a correlation peak has been identified, or all roots have been tested without identifying a correlation peak (e.g., an error condition).

[0137] For example, since the UE 115 generates a preamble sequence (e.g., SEQ00) using a first root preamble sequence μ0, a correlation peak 430-a may be identified on a graph 425-a of the number of samples and amplitude of the first root μ0. Since the UE 115 generates a preamble sequence (e.g., SEQ01) using a second root preamble sequence μ1, a correlation peak 430-b may be identified on a graph 425-b for SEQ01 and the root μ1. Due to the wireless channel between the UE 115 and the base station 105 (or the satellite 120), each correlation peak 430-a and 430-b may be shifted by the RTD and frequency shifted due to the Doppler effect between the UE 115 transmitting the preamble 405 and the satellite 120 detecting the preamble 405. However, the frequency shift and RTD may not affect the detection of the root. Each detected root μ0 and μ1 may be paired to complete the preamble detection. Based on the detection of the roots μ0 and μ1, the satellite 120 may estimate the RTD and frequency shift.

[0138] There may be q identical roots μ n In a system of , satellite 120 may maintain q possible peak locations. However, regardless of the number of possible peak locations, the detection of the root may remain unambiguous.

[0139] In some cases, the satellite 120 may assume that q=1. In this case, some assumptions may be included in the estimation of the RTD and frequency shift. These assumptions may include that the peak position is an integer multiple of samples, where a sample may be represented as b0, b1. These assumptions may also include that the RTD is measured in integer numbers of samples, the Doppler shift is measured in integer multiples of SCS, and that the roots μ0 and μ1 have anti-roots and Based on these assumptions, two equations can be solved to calculate the RTD (expressed as delay in Equation 3) and the frequency shift (expressed as doppler in Equation 3).

[0140]

[0141] Satellite 120 can solve Equation 3 for each root μ0 and μ1. In some cases, the delay range may be less than N and the Doppler range may be less than N. In this case, Equations 3 and 4 in the following solution can uniquely identify the delay and Doppler. The solution equations for RTD are as follows:

[0142]

[0143] The solution equation for the frequency shift is as follows:

[0144]

[0145] When the delay range is less than the preamble sequence length N and the Doppler range is less than the preamble sequence length N, Equations 4 and 5 can uniquely identify the RTD and Doppler shift caused by the distance between the UE 115 sending the preamble and the satellite 120 (or base station 105 in the case of a terrestrial network) receiving and demodulating the preamble.

[0146] Alternatively or additionally, q may be greater than 1. In this case, there may be at most q 2 peak position pairs. In this case, q can be removed from the list of potential pairs. 2 -1 pairs. In one example, delay and Doppler can be solved separately for each root pair possibility. In this example, impossible values ​​of delay and Doppler can be removed. If there is a prior indication of the delay and Doppler range, these impossible values ​​can be removed so that values ​​outside the range can be removed. In addition, P pairs (μ0, μ1) can be selected wisely so that peak position pairs can be removed accordingly.

[0147] Therefore, the satellite 120 can jointly detect the preamble sent by the UE 115 and also estimate the RTD and frequency shift (e.g., Doppler effect) caused by the distance between the UE 115 and the satellite 120. For 120kHz SCS, the preamble transmission and RACH process can withstand Doppler shifts of up to ±500kHz, and the CP may be long enough to cover the maximum delay difference.

[0148] The estimates of RTD and Doppler shift may depend on the location of the detected peak. This may lead to potential errors in the estimates in equations 4 and 5. The errors may occur in the number of samples b0 and b1. The errors in these samples scale as shown in equations 4 and 5. Therefore, the error can be reduced by UE 115 selecting the root pair v0 and μ1 so that or smaller (e.g., less than or equal to the threshold), so b0 and b1 cannot be scaled by a factor greater than 1.

[0149] Similarly, satellite 120 may receive preamble 405-b, which may be a preamble generated by UE 115 according to preamble design 302 and sent by UE 115 to satellite 120. Satellite 120 may demodulate preamble 405-b by clipping FFT window 420-c to detect dual roots SEQ00 and SEQ01 of the preamble in OFDM symbol 415-c.

[0150] The double roots of preamble 405-b may correspond to correlation peaks 430-a and 430-b after correlation processing by satellite 120. Satellite 120 may solve equations 3, 4, and 5 to determine the delay and Doppler effect for preamble 405-b. In some cases, satellite 120 may send an indication of the estimated delay and Doppler effect to UE 115.

[0151] Figure 5 An example of a process flow 500 for supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. In some examples, the process flow 500 can implement aspects of the wireless communication system 100. The process flow 500 can illustrate an example of generating and transmitting a dual-root preamble by a UE 115. The UE 115-b can be as described in reference Figures 1 to 4 The satellite 120-b may be an example of a UE 115. Figures 1 to 4 The satellite 120 is an example of a satellite 120. The satellite 120 may be an example of a non-ground base station. In some cases, the satellite 120 may be replaced by a base station 105 in a ground network. The following alternative examples may be implemented, where some of the steps are performed in a different order than described, or not performed at all. In some cases, the steps may include additional features not mentioned below, or further steps may be added.

[0152] The wireless device 120-b may be shown as a satellite in the process flow 500. The wireless device 120-b may be a satellite 120-b in an NTN, but may be a ground base station in other cases (e.g., as shown in FIG. Figure 1 and Figure 2 The base station 105).

[0153] At 505, the satellite 120-b may transmit a signal indicating a set of root preamble sequences (eg, ZC root μ0, μ1, ..., μ N At 505, UE 115-b may receive control signaling indicating a set of root preamble code sequences from satellite 120-b.

[0154] At 510, UE 115-b may generate a preamble signal (e.g., preamble 305 including a cyclic prefix and a preamble sequence). The generation of the preamble signal may include generating a preamble sequence pair set based on a root preamble sequence set, wherein each first tuple of each preamble sequence pair of the preamble sequence pair set is unique, and each second tuple of each preamble sequence pair of the preamble sequence pair set is unique. In addition, UE 115-b may generate a preamble sequence pair set based on the root preamble sequence set, wherein each first tuple of each preamble sequence pair of the preamble sequence pair set is unique.

[0155] UE 115-b may append a first CP to a first root preamble sequence and a second CP to a second root preamble sequence to generate a combined sequence, wherein a preamble signal is generated based on the combined preamble sequence. UE 115-b may append a first CP to a first root preamble sequence to generate a first appended preamble sequence and append a second CP to a second root preamble sequence to generate a second appended preamble sequence.

[0156] At 515, UE 115-b may transmit a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of a root preamble sequence set. In some cases, UE 115-b may transmit the preamble signal over two symbol periods that are consecutive in time. In other cases, UE 115-b may transmit a first preamble signal generated based on a first root preamble sequence during a first symbol period, and transmit a second preamble signal generated based on a second root preamble sequence during a second symbol period that is consecutive in time.

[0157] In some cases, transmitting the preamble signal may include transmitting the preamble signal generated based on a first root preamble sequence pair including a first root preamble sequence and a second root preamble sequence.

[0158] UE 115-b may transmit a first preamble signal generated based on a first additional preamble sequence (e.g., CP0+SEQ00) in a first frequency resource. UE 115-b may also transmit a second preamble signal generated based on a second additional preamble sequence (e.g., CP1+SEQ01) in a second frequency resource. In some cases, the first preamble signal and the second preamble signal are transmitted during a single symbol period.

[0159] The GT may satisfy the RTD threshold. The length of each of the first preamble sequence and the second preamble sequence may satisfy the CP length threshold. Each of the first preamble sequence and the second preamble sequence may be a ZC sequence.

[0160] At 515, the satellite 120-b may receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set. The reception of the preamble signal may include receiving the preamble signal over two symbol periods that are consecutive in time. The reception of the preamble signal may also include receiving a first preamble signal generated based on the first root preamble sequence during a first symbol period, and receiving a second preamble signal generated based on the second root preamble sequence during a second symbol period that is consecutive in time to the first symbol period. The reception of the preamble signal may also include receiving a preamble signal generated based on a first root preamble sequence pair including the first root preamble sequence and the second root preamble sequence. The satellite 120-b may receive the first preamble signal in a first frequency resource, and may receive the second preamble signal in a second frequency resource. The first preamble signal and the second preamble signal may be sent by the UE 115-b during a single symbol period.

[0161] At 520, UE 115-b may monitor for a preamble response based on the preamble signal. In some cases, based on monitoring for the response, UE 115-b may send a second preamble signal based on determining that a preamble response has not been received from satellite 120-b.

[0162] At 525, the satellite 120-b may demodulate the received preamble signal. This may include performing a first correlation of a first signal received during a first symbol period with each of the set of root preamble sequences to identify the first root preamble sequence. The satellite 120-b may also perform a second correlation of a second signal received during a second symbol period with each of the set of root preamble sequences to identify the second root preamble sequence. The satellite 120-b may identify a Doppler shift, delay, or both based on the first correlation, the second correlation, or both, and may use the identified Doppler shift or delay, or both, to demodulate a subsequent transmission received from the UE 115-b.

[0163] At 530, the satellite 120-b may send a preamble response based on the preamble signal. At 530, the UE 115-b may receive the preamble response from the satellite 120-b. At 535, the UE 115-b may establish a connection with the satellite 120-b based on the preamble response. The satellite 120-b may establish a connection with the UE 115-b based on the preamble response.

[0164] The satellite 120-b may transmit a Doppler indicator, a delay indicator, or both based on the preamble signal at 540. The UE 115-b may receive the Doppler indicator, the delay indicator, or both based on the preamble signal.

[0165] At 550, UE 115-b may send a data transmission, a control transmission, or both using a waveform that is pre-compensated based on the Doppler indicator, the delay indicator, or both (e.g., adjusting the waveform to reduce or eliminate the effect of Doppler or delay, or both, on the data transmission, control transmission, or both received by satellite 120-b). Satellite 120-b may receive the data transmission, the control transmission, or both using a waveform that is pre-compensated based on the Doppler indicator, the delay indicator, or both. Satellite 120-b may demodulate the data transmission, the control transmission, or both based on the Doppler indicator, the delay indicator, or both.

[0166] Figure 6 A block diagram 600 of a device 605 supporting a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. The device 605 may be an example of aspects of a UE 115 as described herein. The device 605 may include a receiver 610, a communication manager 615, and a transmitter 620. The device 605 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0167] The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to dual-root preamble design for delay and frequency shift, etc.). The information may be delivered to other components of the device 605. The receiver 610 may be a reference Fig. 9 Examples of aspects of transceiver 920 are described. Receiver 610 may utilize a single antenna or a group of antennas.

[0168] The communication manager 615 may receive control signaling indicating a root preamble sequence set, send a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and monitor a preamble response based on the preamble signal. The communication manager 615 may be an example of aspects of the communication manager 910 described herein.

[0169] The communication manager 615 or its subcomponents may be implemented by hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communication manager 615 or its subcomponents may be performed by a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device designed to perform the functions described herein, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

[0170] The communication manager 615 or its subcomponents can be physically located in a variety of locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, the communication manager 615 or its subcomponents can be separate and distinct components according to various aspects of the present disclosure. In some examples, the communication manager 615 or its subcomponents can be combined with one or more other hardware components, including but not limited to input / output (I / O) components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination according to various aspects of the present invention.

[0171] Transmitter 620 can transmit signals generated by other components of device 605. In some examples, transmitter 620 can be collocated with receiver 610 in a transceiver module. For example, transmitter 620 can be a reference Fig. 9 Examples of aspects of the transceiver 920 are described. The transmitter 620 may utilize a single antenna or a group of antennas.

[0172] In some examples, the communication manager 615 described herein may be implemented as a chipset for a wireless modem, and the receiver 610 and the transmitter 620 may be implemented as an analog component group (e.g., amplifier, filter, phase shifter, antenna, etc.). The wireless modem may acquire and decode a signal from the receiver 610 through a receiving interface, and may output a signal for transmission to the transmitter 620 through a transmitting interface.

[0173] The actions performed by the communication manager as described herein may be implemented to achieve one or more potential advantages. An implementation may allow UE 115 to communicate more efficiently in the NTN. UE 115 may pre-compensate subsequent transmissions based on the reception using receiver 610 and indications of delay and Doppler effect. The pre-compensated signal may be sent by transmitter 620. This may result in improved efficiency and high reliability transmissions for UE 115 and satellite 120 (or base station 105 in a terrestrial network).

[0174] Figure 7 A block diagram 700 of a device 705 supporting a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. The device 705 may be an example of aspects of the device 605 or UE 115 as described herein. The device 705 may include a receiver 710, a communication manager 715, and a transmitter 735. The device 705 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0175] The receiver 710 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to dual-root preamble design for delay and frequency shift, etc.). The information may be delivered to other components of the device 705. The receiver 710 may be a reference Fig. 9 Examples of aspects of the transceiver 920 are described. The receiver 710 may utilize a single antenna or a group of antennas.

[0176] Communications manager 715 may be an example of aspects of communications manager 615 as described herein. Communications manager 715 may include control signaling component 720, preamble signal generation component 725, and response monitoring component 730. Communications manager 715 may be an example of aspects of communications manager 910 as described herein.

[0177] Control signaling component 720 can receive control signaling indicating a root preamble sequence set.

[0178] The preamble signal generating component 725 may transmit a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of a root preamble sequence set.

[0179] Response monitoring component 730 can monitor for a preamble response based on the preamble signal.

[0180] Transmitter 735 can transmit signals generated by other components of device 705. In some examples, transmitter 735 can be collocated with receiver 710 in a transceiver module. For example, transmitter 735 can be a reference Fig. 9 Examples of aspects of the transceiver 920 are described. The transmitter 735 may utilize a single antenna or a group of antennas.

[0181] Figure 8 A block diagram 800 of a communication manager 805 is shown that supports a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure. The communication manager 805 can be an example of aspects of the communication manager 615, the communication manager 715, or the communication manager 910 described herein. The communication manager 805 can include a control signaling component 810, a preamble signal generation component 815, a response monitoring component 820, a sequence generation component 825, a pre-compensation component 830, and a CP generation component 835. Each of these modules can communicate with each other directly or indirectly (e.g., via one or more buses).

[0182] The control signaling component 810 may receive control signaling indicating a root preamble sequence set. The preamble signal generation component 815 may send a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set. In some examples, the preamble signal generation component 815 may send a preamble signal over two symbol periods that are consecutive in time. In some examples, the preamble signal generation component 815 may send a first preamble signal generated based on a first root preamble sequence during a first symbol period.

[0183] In some examples, the preamble signal generating component 815 may transmit a second preamble signal generated based on a second root preamble sequence during a second symbol period that is temporally continuous with the first symbol period.

[0184] In some examples, a preamble signal generated based on a first root preamble sequence pair including a first root preamble sequence and a second root preamble sequence is transmitted. In some examples, the preamble signal generating component 815 may transmit a first preamble signal generated based on a first additional preamble sequence in a first frequency resource.

[0185] In some examples, the preamble signal generating component 815 may transmit a second preamble signal generated based on a second additional preamble sequence in a second frequency resource. In some cases, the first preamble signal and the second preamble signal are transmitted during a single symbol period. In some cases, the guard time satisfies a round trip delay threshold. In some cases, the length of each of the first root preamble sequence and the second root preamble sequence satisfies a cyclic prefix length threshold. In some cases, each of the first root preamble sequence and the second root preamble sequence is a Zadoff-Chu sequence.

[0186] The response monitoring component 820 can monitor the preamble response based on the preamble signal. In some examples, the response monitoring component 820 can send a second preamble signal based on determining that the preamble response is not received. In some examples, the response monitoring component 820 can receive the preamble response from the satellite or base station. In some examples, the response monitoring component 820 can establish a connection with the satellite or base station based on the preamble response.

[0187] The sequence generation component 825 may generate a set of preamble sequence pairs based on the root preamble sequence set, wherein each first tuple of each preamble sequence pair of the set is unique and each second tuple of each preamble sequence pair of the set is unique.

[0188] In some examples, the sequence generation component 825 can generate a set of preamble code sequence pairs based on the root preamble code sequence set, wherein each first tuple of each preamble code sequence pair of the preamble code sequence pair set is unique, or each second tuple of each preamble code sequence pair of the preamble code sequence pair set is unique.

[0189] Precompensation component 830 can receive a Doppler indicator, a delay indicator, or both based on the preamble signal. In some examples, precompensation component 830 can send a data transmission, a control transmission, or both using a waveform precompensated based on the Doppler indicator, the delay indicator, or both.

[0190] The CP generation component 835 may append a first cyclic prefix to the first root preamble sequence and append a second cyclic prefix to the second root preamble sequence to generate a combined root preamble sequence, wherein a preamble signal is generated based on the combined preamble sequence. In some examples, the CP generation component 835 may append a first cyclic prefix to the first root preamble sequence to generate a first additional preamble sequence, and append a second cyclic prefix to the second root preamble sequence to generate a second additional preamble sequence.

[0191] Fig. 9 A diagram of a system 900 is shown that includes a device 905 that supports dual-root preamble design for delay and frequency shift according to aspects of the present disclosure. The device 905 may be an example of or include components of the device 605, device 705, or UE 115 as described herein. The device 905 may include components for two-way voice and data communications, including components for sending and receiving communications, including a communication manager 910, an I / O controller 915, a transceiver 920, an antenna 925, a memory 930, and a processor 940. These components may be in electronic communication via one or more buses (e.g., bus 945).

[0192] The communication manager 910 may receive control signaling indicating a root preamble sequence set, transmit a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and monitor a preamble response based on the preamble signal.

[0193] I / O controller 915 can manage input and output signals for device 905. I / O controller 915 can also manage peripheral devices that are not integrated into device 905. In some cases, I / O controller 915 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 915 can utilize a variety of communication methods such as Or another known operating system. In other cases, I / O controller 915 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 915 may be implemented as part of a processor. In some cases, a user may interact with device 905 via I / O controller 915 or via hardware components controlled by I / O controller 915.

[0194] The transceiver 920 may communicate bidirectionally via one or more antennas, wired or wireless links as described herein. For example, the transceiver 920 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 920 may also include a modem for modulating packets and providing the modulated packets to an antenna for transmission, and demodulating packets received from an antenna.

[0195] In some cases, a wireless device may include a single antenna 925. However, in some cases, a device may have multiple antennas 925, which may be able to send or receive multiple wireless transmissions simultaneously.

[0196] The memory 930 may include random access memory (RAM) and read-only memory (ROM). The memory 930 may store computer-readable computer executable code 935, including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 930 may include, among other things, a basic I / O system (BIOS), which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0197] The processor 940 may include an intelligent hardware device (e.g., a general purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks that support dual-root preamble design for delay and frequency shift).

[0198] The code 935 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communications. The code 935 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 935 may not be directly executable by the processor 940, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0199] The processor 940 of the UE 115 can send a preamble signal based on the generation of the preamble signal. The dual-root preamble signal can be configured to effectively indicate the RTD and Doppler effect to the satellite 120 without additional overhead messages. The effective indication and detection of the RTD and Doppler effect enabled by the processor 940 can reduce delays and allow for improved communication reliability between the UE 115 and the satellite 120 in the NTN. The processor 940 can also send a signal to other components to pre-compensate for further transmissions to the satellite 120, which can reduce the impact of the RTD and Doppler effect on the reception quality and reliability of the transmitted signal.

[0200] Fig.10 A block diagram 1000 of a device 1005 supporting a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. The device 1005 may be an example of aspects of a satellite 120 or a base station 105 as described herein. The device 1005 may include a receiver 1010, a communication manager 1015, and a transmitter 1020. The device 1005 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0201] The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to dual-root preamble design for delay and frequency shift, etc.). The information may be delivered to other components of the device 1005. The receiver 1010 may be a reference Fig.13 Examples of aspects of the transceiver 1320 are described. The receiver 1010 may utilize a single antenna or a group of antennas.

[0202] The communication manager 1015 may send control signaling indicating a root preamble sequence set, receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and send a preamble response based on the preamble signal. The communication manager 1015 may be an example of aspects of the communication manager 1310 described herein.

[0203] The communication manager 1015 or its subcomponents may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communication manager 1015 or its subcomponents may be performed by a general purpose processor, a DSP, an application specific integrated circuit (ASIC), an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination designed to perform the functions described herein.

[0204] The communication manager 1015 or its subcomponents can be physically located in various locations, including being distributed so that portions of the functionality are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the invention, the communication manager 1015 or its subcomponents can be separate and distinct components. In some examples, the communication manager 1015 or its subcomponents can be combined with one or more other hardware components, including but not limited to I / O components, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination according to various aspects of the invention.

[0205] Transmitter 1020 can transmit signals generated by other components of device 1005. In some examples, transmitter 1020 can be collocated with receiver 1010 in a transceiver module. For example, transmitter 1020 can be a reference Fig.13 Examples of aspects of the transceiver 1320 are described. The transmitter 1020 may utilize a single antenna or a group of antennas.

[0206] Fig.11 A block diagram 1100 of a device 1105 supporting a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. The device 1105 may be an example of aspects of the device 1005, satellite 120, or base station 105 as described herein. The device 1105 may include a receiver 1110, a communication manager 1115, and a transmitter 1135. The device 1105 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0207] The receiver 1110 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to dual-root preamble design for delay and frequency shift, etc.). The information may be delivered to other components of the device 1105. The receiver 1110 may be a reference Fig.13 Examples of aspects of transceiver 1320 are described. Receiver 1110 may utilize a single antenna or a group of antennas.

[0208] The communication manager 1115 can be an example of aspects of the communication manager 1015 as described herein. The communication manager 1115 can include a control component 1120, a detection component 1125, and a response component 1130. The communication manager 1115 can be an example of aspects of the communication manager 1310 described herein.

[0209] The control component 1120 may send control signaling indicating the root preamble sequence set. The detection component 1125 may receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set. The response component 1130 may send a preamble response based on the preamble signal.

[0210] Transmitter 1135 can transmit signals generated by other components of device 1105. In some examples, transmitter 1135 can be collocated with receiver 1110 in a transceiver module. For example, transmitter 1135 can be a reference Fig.13 Examples of aspects of the transceiver 1320 are described. The transmitter 1135 may utilize a single antenna or a group of antennas.

[0211] Fig.12 A block diagram 1200 of a communication manager 1205 is shown that supports a dual-root preamble design for delay and frequency shift according to aspects of the present disclosure. The communication manager 1205 can be an example of aspects of the communication manager 1015, the communication manager 1115, or the communication manager 1310 described herein. The communication manager 1205 can include a control component 1210, a detection component 1215, a response component 1220, a connection component 1225, an indication component 1230, an uplink component 1235, and a demodulation component 1240. Each of these modules can communicate with each other directly or indirectly (e.g., via one or more buses).

[0212] The control component 1210 may send control signaling indicating a root preamble sequence set. The detection component 1215 may receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set. In some examples, the detection component 1215 may receive the preamble signal over two symbol periods that are continuous in time. In some examples, the detection component 1215 may receive a first preamble signal generated based on a first root preamble sequence during a first symbol period.

[0213] In some examples, the detection component 1215 may receive a second preamble signal generated based on a second root preamble sequence during a second symbol period that is temporally continuous with the first symbol period. In some examples, the detection component 1215 may perform a first correlation of the first signal received during the first symbol period with each of the root preamble sequence set to identify the first root preamble sequence. In some examples, the detection component 1215 may perform a second correlation of the second signal received during the second symbol period with each of the root preamble sequence set to identify the second root preamble sequence. In some examples, the detection component 1215 may identify the Doppler shift, delay, or both based on the first correlation, the second correlation, or both.

[0214] In some examples, a preamble signal generated based on a first root preamble sequence pair including a first root preamble sequence and a second root preamble sequence is received. In some examples, the detection component 1215 can receive the first preamble signal in a first frequency resource. In some examples, the detection component 1215 can receive the second preamble signal in a second frequency resource.

[0215] In some cases, the first preamble signal and the second preamble signal are sent during a single symbol period. In some cases, the guard time satisfies a round trip delay threshold. In some cases, the length of each of the first root preamble sequence and the second root preamble sequence satisfies a cyclic prefix length threshold. In some cases, each of the first root preamble sequence and the second root preamble sequence is a Zadoff-Chu sequence. In some cases, the wireless device is a ground base station or a satellite.

[0216] The response component 1220 may send a preamble response based on the preamble signal. The connection component 1225 may establish a connection with the user equipment based on the preamble response. The indication component 1230 may send a Doppler indicator, a delay indicator, or both based on the preamble signal. The uplink component 1235 may receive a data transmission, a control transmission, or both using a waveform pre-compensated based on the Doppler indicator, the delay indicator, or both. The demodulation component 1240 may demodulate the data transmission, the control transmission, or both based on the Doppler indicator, the delay indicator, or both.

[0217] Fig.13 A diagram of a system 1300 is shown that includes a device 1305 that supports dual-root preamble design for delay and frequency shift according to aspects of the present disclosure. The device 1305 may be an example of or include components of the device 1005, device 1105, or satellite 120 or base station 105 as described herein. The device 1305 may include components for two-way voice and data communications, including components for sending and receiving communications, including a communication manager 1310, a network communication manager 1315, a transceiver 1320, an antenna 1325, a memory 1330, a processor 1340, and an inter-station communication manager 1345. These components may be in electronic communication via one or more buses (e.g., bus 1350).

[0218] The communication manager 1310 may send control signaling indicating a root preamble sequence set, receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of the root preamble sequence set, and send a preamble response based on the preamble signal.

[0219] The network communications manager 1315 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communications manager 1315 may manage the transmission of data communications for client devices such as one or more UEs 115 .

[0220] The transceiver 1320 may communicate bidirectionally via one or more antennas, wired or wireless links as described herein. For example, the transceiver 1320 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1320 may also include a modem for modulating packets and providing the modulated packets to an antenna for transmission, and demodulating packets received from an antenna.

[0221] In some cases, a wireless device may include a single antenna 1325. However, in some cases, a device may have multiple antennas 1325, which may simultaneously send or receive multiple wireless transmissions.

[0222] Memory 1330 may include RAM, ROM, or a combination thereof. Memory 1330 may store computer readable code 1335, including instructions that, when executed by a processor (e.g., processor 1340), cause the device to perform various functions described herein. In some cases, memory 1330 may include, among other things, BIOS, which may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0223] Processor 1340 may include an intelligent hardware device (e.g., a general purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor 1340 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into processor 1340. Processor 1340 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1330) to cause device 1305 to perform various functions (e.g., functions or tasks that support dual root preamble design for delay and frequency shift).

[0224] The inter-site communication manager 1345 may manage communications with other satellites 120 or base stations 105 and may include a controller or scheduler for controlling communications with UEs 115 in coordination with other satellites 120 or base stations 105. For example, the inter-site communication manager 1345 may coordinate the scheduling of transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmissions. In some examples, the inter-site communication manager 1345 may provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between satellites 120 or base stations 105.

[0225] The code 1335 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communications. The code 1335 may be stored in a non-transitory computer-readable medium, such as a system memory or other type of memory. In some cases, the code 1335 may not be directly executable by the processor 1340, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0226] Fig.14 A flow chart illustrating a method 1400 is shown that supports dual-root preamble design for delay and frequency shift according to aspects of the present disclosure. The operations of the method 1400 may be implemented by the UE 115 or its components as described herein. For example, the operations of the method 1400 may be performed by a communication manager as described with reference to Figures 6 to 9. In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described herein.

[0227] At 1405, the UE may receive control signaling indicating a root preamble sequence set. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be as described in reference to Figures 6 to 9 The control signaling component is used to perform the above.

[0228] At 1410, the UE may send a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of a root preamble sequence set. The operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be as described in reference to Figures 6 to 9 The preamble signal generation component is used to perform.

[0229] At 1415, the UE may monitor for a preamble response based on the preamble signal. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be as described in reference to Figures 6 to 9 The response monitoring component is used to perform the above operation.

[0230] Fig.15 1 shows a flow chart illustrating a method 1500 for supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure. The operations of the method 1500 may be implemented by the UE 115 or components thereof as described herein. For example, the operations of the method 1500 may be implemented by the UE 115 or components thereof as described herein. Figures 6 to 9 The communication manager described herein performs. In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described herein.

[0231] At 1505, the UE may receive control signaling indicating a root preamble sequence set. The operations of 1505 may be performed according to the methods described herein. In some examples, aspects of the operations of 1505 may be performed as described in reference to Figures 6 to 9 The control signaling component is used to execute.

[0232] At 1510, the UE may send a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of a root preamble sequence set. The operations of 1510 may be performed according to the methods described herein. In some examples, aspects of the operations of 1510 may be as described in reference to Figures 6 to 9 The preamble signal generation component is used to perform.

[0233] At 1515, the UE may transmit a first preamble signal generated based on a first root preamble sequence during a first symbol period. The operations of 1515 may be performed according to the methods described herein. In some examples, aspects of the operations of 1515 may be as described in reference to Figures 6 to 9 The preamble signal generation component is used to perform.

[0234] At 1520, the UE may transmit a second preamble signal generated based on a second root preamble sequence during a second symbol period that is temporally continuous with the first symbol period. The operations of 1520 may be performed according to the methods described herein. In some examples, aspects of the operations of 1520 may be as described in reference to Figures 6 to 9 The preamble signal generation component is used to perform.

[0235] At 1525, the UE may monitor for a preamble response based on the preamble signal. The operations of 1525 may be performed according to the methods described herein. In some examples, aspects of the operations of 1525 may be as described in reference to Figures 6 to 9 The response monitoring component is used to perform the above operation.

[0236] Fig.16 A flow chart illustrating a method 1600 for supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. The operations of the method 1600 may be implemented by the satellite 120 or the base station 105 or components thereof, as described herein. For example, the operations of the method 1600 may be implemented by the satellite 120 or the base station 105 as described in reference to Figures 10 to 13 The communication manager performs. In some examples, the satellite or base station may execute a set of instructions to control the functional elements of the base station to perform the functions described herein. Additionally or alternatively, the satellite or base station may use dedicated hardware to perform aspects of the functions described herein.

[0237] At 1605, the satellite or base station may send control signaling indicating a root preamble sequence set. The operations of 1605 may be performed according to the methods described herein. In some examples, aspects of the operations of 1605 may be as described in reference to Figures 10 to 13 The control component is used to execute.

[0238] At 1610, a satellite or base station may receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of a root preamble sequence set. The operations of 1610 may be performed according to the methods described herein. In some examples, aspects of the operations of 1610 may be as described in reference to Figures 10 to 13 The detection component is used to perform the above.

[0239] At 1615, the satellite or base station may send a preamble response based on the preamble signal. The operations of 1615 may be performed according to the methods described herein. In some examples, aspects of the operations of 1615 may be as described in reference to Figures 10 to 13 The response component is executed.

[0240] Fig.17 A flow chart illustrating a method 1700 for supporting dual-root preamble design for delay and frequency shift according to aspects of the present disclosure is shown. The operations of the method 1700 may be implemented by the satellite 120 or the base station 105 or components thereof, as described herein. For example, the operations of the method 1700 may be implemented by the satellite 120 or the base station 105 as described in reference to Figures 10 to 13 In some examples, a satellite or base station may execute a set of instructions to control functional elements of the satellite or base station to perform the functions described herein. Additionally or alternatively, a satellite or base station may use dedicated hardware to perform aspects of the functions described herein.

[0241] At 1705, the satellite or base station may send control signaling indicating a root preamble sequence set. The operations of 1705 may be performed according to the methods described herein. In some examples, aspects of the operations of 1705 may be as described in reference to Figures 10 to 13 The control component is used to execute.

[0242] At 1710, a satellite or base station may receive a preamble signal generated based on a first root preamble sequence and a second root preamble sequence of a root preamble sequence set. The operations of 1710 may be performed according to the methods described herein. In some examples, aspects of the operations of 1710 may be as described in reference to Figures 10 to 13 The detection component is used to perform the above.

[0243] At 1715, the satellite or base station may send a preamble response based on the preamble signal. The operations of 1715 may be performed according to the methods described herein. In some examples, aspects of the operations of 1715 may be as described in reference to Figures 10 to 13 The response component is executed.

[0244] At 1720, the satellite or base station may send a Doppler indicator, a delay indicator, or both based on the preamble signal. The operations of 1720 may be performed according to the methods described herein. In some examples, aspects of the operations of 1720 may be performed as described in reference to Figures 10 to 13 The instruction component is executed.

[0245] At 1725, the satellite or base station may receive a data transmission, a control transmission, or both using a waveform pre-compensated based on the Doppler indicator, the delay indicator, or both. The operations of 1725 may be performed according to the methods described herein. In some examples, aspects of the operations of 1725 may be performed as described in reference to Figures 10 to 13 The uplink component is used to perform the above.

[0246] It should be noted that the methods described herein describe possible implementations, and that operations and steps may be rearranged or otherwise modified, and that other implementations are possible. Furthermore, aspects from two or more methods may be combined.

[0247] The technology described herein can be used for various wireless communication systems, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA) and other systems. CDMA systems can implement radio technologies such as CDMA2000, Universal Terrestrial Radio Access (UTRA). CDMA2000 covers IS-2000, IS-95 and IS-856 standards. IS-2000 versions are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV DO, High Speed ​​Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. TDMA systems can implement radio technologies such as Global System for Mobile Communications (GSM).

[0248] OFDMA systems can implement radio technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein can be used for the systems and radio technologies mentioned herein as well as other systems and radio technologies. Although aspects of LTE, LTE-A, LTE-A-Pro, or NR systems may be described for example purposes, and LTE, LTE-A, LTE-A-Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A-Pro, or NR applications.

[0249] A macro cell typically covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access to a UE by subscribing to a service from a network provider. A small cell may be associated with a base station with lower power than a macro cell, and the small cell may operate in the same or different frequency bands (e.g., licensed, unlicensed, etc.) as the macro cell. According to various examples, a small cell may include a pico cell, a femto cell, and a micro cell. For example, a pico cell may cover a small geographic area and may allow unrestricted access to a UE by subscribing to a service from a network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access to a UE associated with the femto cell (e.g., a UE in a closed subscriber group (CSG), a UE of a user in a home, etc.). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or more (e.g., two, three, four, etc.) cells and may also support communications using one or more component carriers.

[0250] The wireless communication systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operation.

[0251] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0252] The various illustrative blocks and modules described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors and a DSP core, or any other such configuration).

[0253] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope of the present invention and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of them. Features that implement the functions may also be physically located in various locations, including being distributed so that parts of the functions are implemented in different physical locations.

[0254] Computer-readable media include non-transitory computer storage media and communication media, and communication media include any media that facilitates the transmission of computer programs from one place to another. Non-transitory storage media can be any available media that can be accessed by a general-purpose or special-purpose computer. As an example and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other non-transitory media that can be used to carry or store the required program code in the form of instructions or data structures and can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. In addition, any connection is properly referred to as a computer-readable medium. For example, if a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwaves are used to send software from a website, server or other remote source, then coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwaves are included in the definition of medium. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0255] As used herein, "or", including in the claims, or as used in a list of items (e.g., a list of items beginning with a phrase such as "at least one" or "one or more") indicates an inclusive list, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). In addition, as used herein, the phrase "based on" should not be interpreted as a reference to a closed set of conditions. For example, an exemplary step described as "based on condition A" can be based on condition A and condition B without departing from the scope of the invention. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on"

[0256] In the drawings, similar components or features may have the same reference label. In addition, various components of the same type may be distinguished by following the reference label with a dash and a second label that distinguishes the similar components. If only the first reference label is used in this specification, the description applies to any one similar component with the same first reference label, regardless of the second reference label or other subsequent reference labels.

[0257] The description set forth herein in conjunction with the accompanying drawings describes exemplary configurations and does not represent all examples that may be implemented or within the scope of the claims. The term "exemplary" as used herein means "used as an example, instance, or illustration," rather than "preferred" or "superior to other examples." The detailed description includes specific details for providing an understanding of the described technology. However, these technologies can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0258] The description herein is intended to enable those skilled in the art to make or use the present invention. Various modifications to the present invention will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present invention. Therefore, the present invention is not limited to the examples and designs described herein, but is given the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication by a user equipment UE, comprising: receiving control signaling indicating a plurality of root preamble sequences; transmitting a dual-root preamble signal over two symbol periods consecutive in time, the dual-root preamble signal being generated at least in part based on a first root preamble sequence and a second root preamble sequence of the plurality of root preamble sequences, and wherein the first root preamble sequence is different from the second root preamble sequence; and A preamble response is monitored based at least in part on the dual preamble signal.

2. The method according to claim 1, wherein: The first preamble sequence is a first Zadoff-Chu sequence different from the second preamble sequence, and the second preamble sequence is a second Zadoff-Chu sequence.

3. The method according to claim 1, wherein: Sending the dual preamble signal includes: transmitting, during a first symbol period, a first preamble signal generated at least in part based on the first root preamble sequence; and A second preamble signal generated at least in part based on the second root preamble sequence is transmitted during a second symbol period that is temporally continuous with the first symbol period.

4. The method according to claim 1, wherein: Monitoring the preamble response includes: A second preamble signal is sent based at least in part on determining that the dual preamble response is not received.

5. The method according to claim 1, wherein: Monitoring the preamble response includes: receiving the preamble response from a base station; and A connection is established with the base station based at least in part on the preamble response.

6. The method according to claim 1, wherein: Sending the dual preamble signal includes: The dual preamble signal generated based at least in part on a first root preamble sequence pair including the first root preamble sequence and the second root preamble sequence is transmitted.

7. The method according to claim 6, further comprising: A plurality of preamble sequence pairs are generated based at least in part on the plurality of root preamble sequences, wherein each first tuple of each preamble sequence pair of the plurality of preamble sequence pairs is unique and each second tuple of each preamble sequence pair of the plurality of preamble sequence pairs is unique.

8. The method according to claim 6, further comprising: A plurality of preamble sequence pairs are generated based at least in part on the plurality of root preamble sequences, wherein each first tuple of each preamble sequence pair of the plurality of preamble sequence pairs is unique or each second tuple of each preamble sequence pair of the plurality of preamble sequence pairs is unique.

9. The method according to claim 1, further comprising: receiving a Doppler indicator, a delay indicator, or both based at least in part on the dual preamble signal; as well as A data transmission, a control transmission, or both is sent using a waveform that is pre-compensated based at least in part on the Doppler indicator, the delay indicator, or both.

10. The method according to claim 1, further comprising: A first cyclic prefix is ​​appended to the first root preamble sequence and a second cyclic prefix is ​​appended to the second root preamble sequence to generate a combined root preamble sequence, wherein the dual root preamble signal is generated based at least in part on the combined root preamble sequence.

11. The method according to claim 1, further comprising: A first cyclic prefix is ​​appended to the first root preamble sequence to generate a first appended preamble sequence, and a second cyclic prefix is ​​appended to the second root preamble sequence to generate a second appended preamble sequence.

12. The method according to claim 11, wherein: Sending the dual preamble signal includes: sending, in a first frequency resource, a first preamble signal generated at least in part based on the first additional preamble sequence; and A second preamble signal generated at least in part based on the second supplemental preamble sequence is transmitted in a second frequency resource.

13. The method according to claim 12, wherein: The first preamble signal and the second preamble signal are transmitted during a single symbol period.

14. The method according to claim 1, wherein: The guard time meets the round trip delay threshold.

15. The method according to claim 1, wherein: A length of each of the first root preamble sequence and the second root preamble sequence satisfies a cyclic prefix length threshold.

16. The method according to claim 1, wherein: The control signaling and the preamble response are received from a satellite, and the dual preamble signal is transmitted to the satellite.

17. A method for wireless communication via a wireless device, comprising: sending control signaling indicating a plurality of root preamble sequences; receiving a dual-root preamble signal over two temporally consecutive symbol periods, the dual-root preamble signal being generated at least in part based on a first root preamble sequence and a second root preamble sequence of the plurality of root preamble sequences, and wherein the first root preamble sequence is different from the second root preamble sequence; and A preamble response is transmitted based at least in part on the dual preamble signal.

18. The method according to claim 17, wherein: The first preamble sequence is a first Zadoff-Chu sequence different from the second preamble sequence, and the second preamble sequence is a second Zadoff-Chu sequence.

19. The method according to claim 17, wherein: Receiving the dual preamble signal includes: receiving, during a first symbol period, a first preamble signal generated at least in part based on the first root preamble sequence; and During a second symbol period that is temporally continuous with the first symbol period, a second preamble signal generated at least in part based on the second root preamble sequence is received.

20. The method according to claim 19, wherein: Receiving the first preamble signal includes: performing a first correlation of a first signal received during the first symbol period with each of the plurality of root preamble sequences to identify the first root preamble sequence; performing a second correlation of a second signal received during the second symbol period with each of the plurality of root preamble sequences to identify the second root preamble sequence; and A Doppler shift, a delay, or both is identified based at least in part on the first correlation, the second correlation, or both.

21. The method of claim 17, further comprising: A connection is established with a user equipment based at least in part on the preamble response.

22. The method according to claim 17, wherein: Receiving the dual preamble signal includes: The dual preamble signal generated based at least in part on a first root preamble sequence pair including the first root preamble sequence and the second root preamble sequence is received.

23. The method of claim 17, further comprising: transmitting a Doppler indicator, a delay indicator, or both based at least in part on the dual preamble signal; as well as A data transmission, a control transmission, or both is received using a waveform pre-compensated based at least in part on the Doppler indicator, the delay indicator, or both.

24. The method of claim 17, further comprising: transmitting a Doppler indicator, a delay indicator, or both based at least in part on the dual preamble signal; as well as A data transmission, a control transmission, or both is demodulated based at least in part on the Doppler indicator, the delay indicator, or both.

25. The method of claim 17, wherein: Receiving the dual preamble signals includes: receiving a first preamble signal in a first frequency resource; and A second preamble signal is received in a second frequency resource.

26. The method according to claim 25, wherein: The first preamble signal and the second preamble signal are transmitted during a single symbol period.

27. The method of claim 17, wherein: A length of each of the first root preamble sequence and the second root preamble sequence satisfies a cyclic prefix length threshold.

28. The method of claim 17, wherein: The wireless device is a satellite, the control signaling and the preamble response are transmitted to a user equipment (UE), and the dual-root preamble signal is received from the UE.

29. An apparatus for wireless communication via a user equipment UE, comprising: means for receiving control signaling indicating a plurality of root preamble sequences; means for transmitting a dual preamble signal over two symbol periods consecutive in time, the dual preamble signal being generated based at least in part on a first root preamble sequence and a second root preamble sequence of the plurality of root preamble sequences, and wherein the first root preamble sequence is different from the second root preamble sequence; and Means for monitoring for a preamble response based at least in part on the dual preamble signal.

30. An apparatus for wireless communication via a wireless device, comprising: means for sending control signaling indicating a plurality of root preamble sequences; means for receiving a dual preamble signal over two symbol periods consecutive in time, the dual preamble signal being generated based at least in part on a first root preamble sequence and a second root preamble sequence of the plurality of root preamble sequences, and wherein the first root preamble sequence is different from the second root preamble sequence; and Means for transmitting a preamble response based at least in part on the dual preamble signal.

31. A non-transitory computer-readable medium storing code for wireless communication via a user equipment (UE), the code comprising instructions executable by a processor to: receiving control signaling indicating a plurality of root preamble sequences; transmitting a dual-root preamble signal over two symbol periods consecutive in time, the dual-root preamble signal being generated at least in part based on a first root preamble sequence and a second root preamble sequence of the plurality of root preamble sequences, and wherein the first root preamble sequence is different from the second root preamble sequence; and A preamble response is monitored based at least in part on the dual preamble signal.

32. A non-transitory computer-readable medium storing code for wireless communication via a wireless device, the code comprising instructions executable by a processor to: sending control signaling indicating a plurality of root preamble sequences; receiving a dual-root preamble signal over two temporally consecutive symbol periods, the dual-root preamble signal being generated at least in part based on a first root preamble sequence and a second root preamble sequence of the plurality of root preamble sequences, and wherein the first root preamble sequence is different from the second root preamble sequence; and Used to send a preamble response based at least in part on the dual preamble signal.

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