Method and apparatus for performing satellite communications

Abstract

An apparatus for a network access node is provided, the apparatus including: a memory; and a processor configured to: determine a time-division duplex communication mode, the time-division duplex communication mode including a plurality of time slots for communication between the network access node and a terminal device; allocate a first time slot among the plurality of time slots to the network access node to perform uplink communication and / or downlink communication; allocate a plurality of second time slots among the plurality of time slots, during which the network access node is scheduled to neither perform uplink communication nor downlink communication with the terminal device, wherein the number of second time slots is based on the round-trip time delay of the network access node; and schedule the terminal device to transmit uplink communication signals or receive downlink communication signals during at least one of the plurality of second time slots.

Description

Background Technology

[0001] A radio access network (RAN) can refer to a component of a wireless communication network responsible for wirelessly connecting terminal devices (such as smartphones, tablets, or other user equipment (UEs)) to the network. A RAN can include several components, including network access nodes (e.g., base stations), antennas, and transceivers that facilitate the transmission and reception of radio signals between devices and the network. Base stations process these radio signals and forward them to the core network for further routing and control. In modern cellular networks (such as 4G LTE, 5G, and 6G), RANs are designed to ensure connectivity, manage radio resources, and maintain communication quality across large geographical areas.

[0002] Non-terrestrial networks have emerged as an extension of traditional radio access networks, including satellite-based communication systems. Part of the 3rd Generation Partnership Project (3GPP) standards, non-terrestrial networks aim to integrate satellite and terrestrial cellular networks to provide wider coverage, particularly in remote or underserved areas. Satellite-based networks can use satellites as additional nodes in the radio access network infrastructure, enabling terminal devices and network access nodes to connect via satellite links. This connection can be established using satellite when terrestrial coverage is unavailable. Compared to terrestrial radio access networks, these satellite-based networks (such as non-terrestrial networks) may face certain challenges, such as higher propagation delays and Doppler shift due to the relative motion of satellites. Addressing these challenges is expected. Attached Figure Description

[0003] In the accompanying drawings, similar reference characters across different views generally refer to the same parts. The drawings are not necessarily drawn to scale; rather, the emphasis is usually on illustrating the principles described herein. In the following description, various aspects are described with reference to the accompanying drawings, wherein:

[0004] Figure 1 and Figure 2 It describes a general network and device architecture for wireless communication;

[0005] Figure 3 An exemplary internal configuration of a communication device is shown;

[0006] Figure 4 An example is shown illustrating a satellite communication system with a service link and a feeder link;

[0007] Figure 5 An example of a timing diagram illustrating the downlink and uplink communication slots is shown;

[0008] Figure 6 An example of a timing diagram is shown;

[0009] Figure 7 A schematic diagram illustrating various latency parameters in a communication scenario between a network access node and a terminal device is shown.

[0010] Figure 8 An example of a flowchart based on the various aspects described in this document is shown;

[0011] Figure 9 An example of a flowchart based on the various aspects described in this document is shown;

[0012] Figure 10 An example of the method is shown;

[0013] Figure 11 An example of the method is shown. Detailed Implementation

[0014] The following detailed description refers to the accompanying drawings, which illustrate exemplary details and aspects that can be practiced by way of illustration.

[0015] Traditional wireless communication systems (especially cellular systems such as LTE and 5G NR) are designed primarily for wireless data transmission and communication purposes. These systems can employ various techniques to enhance data throughput, reliability, and spectral efficiency, including multiple-input multiple-output (MIMO), beamforming, and spatial multiplexing. By using MIMO, multiple antennas at the transmitter and receiver can use the same frequency band to provide spatial diversity and simultaneous transmission of multiple data streams. Additionally, beamforming can focus signal energy onto the intended receiver for purposes such as improving signal quality and mitigating interference. Furthermore, spatial multiplexing can employ different propagation paths within a wireless environment to simultaneously transmit multiple data streams, thereby increasing overall capacity.

[0016] In the field of wireless network communication, networks can utilize time-division duplex (TDM) communication modes to manage uplink and downlink transmissions between network access nodes and terminal devices (e.g., user equipment). Traditionally, wireless communication using TDM within a wireless access network can include allocating time slots for uplink and downlink communication based on predefined scheduling. However, wireless access networks may face challenges related to round-trip time (RTT), which can affect the efficiency and reliability of data transmission. RTT can be affected by various factors, including the distance between the network access node and the terminal device, and because the delay associated with the propagation of wireless communication signals through the air increases with distance, RTT can vary significantly in non-terrestrial networks such as satellite-based networks.

[0017] In satellite-based communications, communication devices that may lack Global Navigation Satellite System (GNSS) capabilities can access and communicate via satellite networks. This can solve two common problems in satellite communications: i) significant delays caused by the vast distance between the satellite and ground equipment; and ii) Doppler shift and sampling shift caused by the high speed of the satellite during its flyby. It should be noted that without GNSS capabilities or knowledge of the satellite's orbit, the device may not be able to accurately determine the amount of propagation delay. Furthermore, Doppler shift and sampling shift may make pre-compensation for these effects infeasible. Illustratively, the device can be a user equipment, a handheld device, or a very small aperture terminal.

[0018] When a device, unaware of a satellite's orbit, attempts to use communication technologies (such as 4G or 5G cellular) for satellite access and communication, substantial latency between the device and the satellite can lead to a loss of the designated timing budget for communication, illustratively, a loss of the 3GPP telecommunications standard timing budget known as Time Division Duplex (TDM) slot formats or TDM modes. These TDM slot formats can be viewed as agreed-upon patterns of transmit and receive times between the network and the handheld device, with each TDM slot alternating when to transmit and when to receive. Significant latency can cause a mismatch between device and satellite time, resulting in overlap of transmitted and received signals, leading to significant spectral efficiency losses. Simultaneously, in orthogonal frequency division multiplexing (OFDM) based communication systems, Doppler offset and sampling offset, primarily caused by satellite movement, can lead to severe system performance degradation. This performance loss can affect both TDM and FDM systems. Doppler offset can refer to the change in carrier frequency that occurs when the satellite moves toward or away from the device. Sampling offset can be a distortion in the time domain signal caused by the compression or expansion of the signal due to changes in the distance between the satellite and the equipment during signal transmission or reception.

[0019] As used herein, round-trip time can refer to the total time it takes for a signal to travel from its source to its destination and back. Round-trip time can be particularly important in satellite communications because the long distance between ground equipment and the satellite often results in significant delays. In some examples, round-trip time delay can include propagation delay, which is the time it takes for a signal to travel through air and space. Other factors, such as processing delays at the satellite and ground stations, can also be included. Propagation delay, or round-trip time delay, can be determined by the distance between the satellite and the equipment and is typically measured in milliseconds. For example, in geostationary satellite systems, round-trip times can exceed 500 milliseconds due to the distance between the Earth and the satellite.

[0020] As used herein, time division duplex (TDD) refers to a communication method in which uplink and downlink transmissions can occur on the same frequency but at different times. In a TDD system, time slots can be alternately allocated for transmitting and receiving data, allowing two communication directions to share the same frequency band. A TDD mode can be defined as how these time slots are allocated between the uplink and downlink within a given frame. In the context of cellular communication, according to 3GPP standards, TDD modes can be configurable based on network requirements, allowing for flexible resource allocation according to service needs.

[0021] As used herein, a time slot can refer to a specific interval within a communication frame during which data transmission or reception occurs. In a time-division duplex system, time slots can be divided between uplink and downlink operations. Each time slot can correspond to a fixed duration (such as 1 millisecond in LTE or NR systems) during which transmission or reception can occur. The number of time slots allocated to the uplink and downlink can vary depending on the time-division duplex mode being used. In the context of cellular communications, in systems defined by 3GPP, such as 5G NR, time slots can also be divided into subframes and symbols.

[0022] As used herein, Doppler shift can refer to the change in signal frequency caused by the relative motion between the transmitter and receiver. In satellite communications, this effect can become significant due to the high speed of the satellite relative to ground equipment. As the satellite moves toward or away from the equipment, it can cause a shift in the carrier frequency of the transmitted signal. This frequency shift can degrade system performance by introducing errors into frequency synchronization, particularly in systems based on orthogonal frequency division multiplexing (OFDM).

[0023] As used herein, sampling offset refers to the phenomenon that occurs when there is a mismatch between the sampling rates of two communication devices due to relative motion or clock inaccuracy. In satellite communications, changes in signal timing as the satellite moves relative to ground equipment can cause sampling offset. This offset can lead to distortion of the received signal because the received signal is sampled too quickly or too slowly compared to the original transmission rate. Over time, sampling offset can cause a significant deterioration in signal quality, especially in orthogonal frequency division multiplexing (OFDM) based systems where accurate timing is crucial for maintaining orthogonality between subcarriers.

[0024] In traditional time-division duplex communication systems, both the terminal device and the network access node (e.g., a satellite-based network access node) can follow a symmetric time-division duplex slot format, where uplink and downlink transmissions occur within the same time slot for both the terminal device and the satellite. This symmetry ensures coordination between transmission and reception operations in terrestrial networks where propagation delays are relatively small. However, in satellite communications, the significant propagation delay caused by the large distance between the satellite-based network access node and the ground device can lead to timing mismatches between the terminal device's transmission and the satellite's reception. This mismatch can cause overlap between transmitted and received signals, resulting in interference, reduced spectral efficiency, and degraded communication performance. This problem may be particularly relevant in non-terrestrial networks, where round-trip time delays are much greater compared to terrestrial networks.

[0025] Based on the aspects described herein, terminal devices and network access nodes can use an asymmetric time-division duplex (TDM) slot format to improve spectral efficiency and mitigate the effects of large propagation delays in satellite-based communication systems to communicate with each other. Unlike traditional symmetric TDM modes, the aspects described herein can include an asymmetric allocation of time slots for uplink and downlink transmissions between the terminal device and the satellite access node. Specifically, the resulting TDM mode can offset the satellite's transmission schedule relative to the terminal device's transmission schedule to allow sufficient time for signal propagation without overlap between uplink transmissions from the terminal device and downlink receptions at the network access node. In some examples, the processor can dynamically adjust this offset based on real-time delay measurements or a pre-configured delay model to ensure that transmission and reception remain synchronized despite variations in propagation delay. Therefore, the aspects described herein can facilitate reduced interference, prevention of signal overlap, and improved overall spectral efficiency in non-terrestrial network environments.

[0026] In the example, the processor can schedule the terminal device to perform neither uplink nor downlink communication during at least one time slot based on round-trip time delay. Illustratively, the processor of the network access node can determine a time-division duplex communication mode, wherein, within a duration defined by multiple time slots, the processor can allocate a first time slot for the network access node to perform uplink and / or downlink communication, while simultaneously allocating a second time slot during which the network access node performs neither uplink nor downlink communication. In some examples, several time slots in the second time slot can be based on a determined round-trip time delay. In such a constellation diagram, the network access node can schedule the terminal device to perform either uplink or downlink communication with the network access during at least one time slot in the second time slot. This configuration can address the problem of significant delays caused by the distance between the network access node and the terminal device (e.g., between a satellite and ground equipment), which can lead to lost 3GPP telecommunications standard timing budgets. By allocating the second time slot based on round-trip time delay, the device can avoid overlap between transmitted and received signals, potentially improving spectral efficiency.

[0027] In the example, the processor can further schedule the terminal device to neither perform uplink communication nor downlink communication with the network access node during at least one of a plurality of first time slots. By allowing the terminal device to remain idle during certain first time slots, the device can improve overall network efficiency and reduce the power consumption of the terminal device by facilitating matching of round-trip delay times within the time slots in which the network access node is scheduled to perform either uplink or downlink communication.

[0028] In the example, the processor can determine the round-trip time delay based on the location of the terminal devices. Given the network access service provided by the network access node to multiple terminal devices within the coverage area, the round-trip time delay can have a common round-trip time delay component determined for the multiple terminal devices within the coverage area, applicable to all terminal devices within the coverage area. Furthermore, each terminal device can be associated with its own further round-trip time delay component, and the combination of the common round-trip time delay component and the respective further round-trip time delay components can indicate the corresponding round-trip time delay specific to that terminal device. Illustratively, the processor can use the determined location of the terminal devices to calculate their respective further round-trip time delays. This approach simplifies the scheduling process and reduces the computational load on the processor. Additionally, it can ensure that communication timing is synchronized across multiple devices, potentially improving overall network performance. Illustratively, the common round-trip time delay component can be the minimum round-trip time delay among the terminal devices within the coverage area.

[0029] Processors can use various methods to determine the orientation of a terminal device. Illustratively, a network access node can receive the orientation of the terminal device from the terminal device. In some examples, the processor can determine the orientation of the terminal device based on the Doppler offset determined for the terminal device. Illustratively, the processor can estimate the position of the terminal device by analyzing the frequency offset caused by the relative motion between the terminal device and the network access node. The Doppler offset can provide information about the velocity and orientation of the terminal device, which can be used to improve the accuracy of orientation determination. This method can be particularly useful in scenarios where GPS signals are weak or unavailable (such as in indoor environments or urban canyons). This feature can also support applications requiring accurate orientation tracking, such as asset tracking, navigation, and orientation-based services. The processor can utilize algorithms to process the Doppler offset data and correlate it with known reference points or signal characteristics to estimate the orientation of the terminal device.

[0030] In the example, the processor can further estimate the respective round-trip time delays based on the physical random access channel transmissions received from the terminal device; in response to the received physical random access channel transmissions, the random access message for the transmission of the random access response is encoded. In this configuration, the timing advance (TA) value in the random access response (RAR) can be based on the round-trip time delay for more accurate synchronization between the network access node and the terminal device.

[0031] Although some aspects can be described as the processor performing the described operations on the terminal devices, the processor can perform these operations on each terminal device within its coverage area. Illustratively, the processor can schedule at least one other terminal device within the coverage area based on a common round-trip time delay component.

[0032] Based on the aspects described herein, a network access node (e.g., a satellite network access node) can perform terminal equipment positioning using a specified reference transmission. One method for determining the initial azimuth of a user equipment (UE) may include utilizing a Physical Random Access Channel (PRAN) transmission. The UE may transmit a PRAN preamble received by the satellite network access node (e.g., a satellite next-generation node B (gNB)). Based on the received PRAN signal, the satellite network access node is able to estimate the distance to the UE relative to its own azimuth and thus determine an azimuth that may be an approximate azimuth. Once the initial position is determined, the satellite-based network access node can continue tracking the UE's azimuth using a demodulated reference signal (DMRS). The demodulated reference signal is embedded in the uplink transmission and allows continued tracking of the UE's position by measuring changes in signal timing and frequency, which may be caused by relative motion between the satellite and the UE. Therefore, an efficient way to maintain accurate positioning of UEs in non-terrestrial networks can be provided without relying on Global Navigation Satellite System (GNSS) data.

[0033] In the example, the processor can estimate the round-trip time delay and Doppler offset associated with the physical random access channel preamble to determine the orientation of the terminal device. This can include analyzing the time it takes for a signal to travel from the terminal device to the network access node, and the frequency offset caused by the relative motion between the terminal device and the network access node. By analyzing the round-trip time delay and Doppler offset, the processor can determine the orientation of the terminal device. This additional step can improve the accuracy of orientation tracking and may be particularly useful in environments where signal reflection or multipath effects are prevalent. The estimation of the round-trip time delay and Doppler offset can also help mitigate errors caused by these effects.

[0034] In illustrative examples where the network access node lacks information about which user equipment is transmitting the physical random access channel (PRAM) preamble and / or which PRAM preamble has been transmitted, the processor can perform hypothesis testing on the PRAM preamble using multiple Doppler offset hypotheses. Each Doppler offset hypothesis can be associated with a respective offset of a frequency symbol received at the PRAM resource. The processor can also: estimate a respective frequency domain channel for the respective offset of the received frequency symbols; and select one of the multiple Doppler offset hypotheses based on the respective frequency domain channel for each Doppler hypothesis. In some examples, the processor can perform this operation for all possible PRAM preambles. The method can further improve the accuracy of uplink transmission configuration by ensuring that the frequency domain channel estimation is based on the most appropriate Doppler offset hypothesis.

[0035] In this scenario, the processor can convert the respective frequency domain channels into corresponding time domain channels, which can help identify peaks in the corresponding time domain channels. The processor can use the identified peaks to determine the round-trip time delay based on the orientation of the peaks. The processor can perform peak identification via any technique including amplitude comparison. For example, the processor can also determine the Doppler shift by selecting the Doppler shift hypothesis with the highest peak or by calculating a linear combination of Doppler shift hypotheses that generate the peaks.

[0036] In the example, the processor can estimate time and frequency offsets based on the received demodulated reference signal to track the orientation of the terminal device. The processor can analyze the timing and frequency characteristics of the demodulated reference signal to determine any deviations from expected values. The processor can then determine how the estimated time and frequency offsets change over time. These changes can indicate the behavior of the terminal device or movement or other changes in the environment. Based on these changes, the processor can update the orientation of the terminal device, which allows for accurate and dynamic tracking of the terminal device's orientation. Alternative implementations may include different algorithms for estimating and updating the offsets, or the use of additional signals or data sources to improve accuracy.

[0037] Based on the aspects described herein, the processor can use aspects related to the scheduling and / or positioning of the terminal device to mitigate Doppler offset and / or sampling offset associated with transmission between the terminal device and the network access node. Furthermore, the network access node mentioned herein can be a network access node that is part of a non-terrestrial network in a cellular communication context. This configuration also enables the processor to support various communication protocols and standards commonly used in satellite communications, such as those defined by 3GPP for non-terrestrial networks.

[0038] As used herein, a satellite can refer to an onboard vehicle carrying a bend (transparent or non-regenerative) payload or a regenerative payload telecommunications transmitter. Satellites can be placed in low Earth orbit (LEO) (typically at altitudes between 500 km and 2000 km), medium Earth orbit (MEO) (typically at altitudes between 8000 km and 20000 km), geostationary satellite orbit (GEO) (at an altitude of 35786 km), or highly elliptical orbit (HEO). The term satellite can also include airborne vehicles typically carrying bend or regenerative payload telecommunications transmitters at altitudes between 8 km and 50 km.

[0039] As used herein, a satellite access node can refer to a satellite that acts as a relay or intermediary between user equipment and a terrestrial network. The satellite can have a transparent payload, allowing it to not process or regenerate received signals, but simply forward them between the user equipment and the ground station. In the context of cellular communications, a satellite can function as a relay node, forwarding signals to a non-terrestrial network gateway, which then connects to the core network. An example of a satellite could be a low Earth orbit satellite. Note that in this configuration, the one-way propagation delay can be equated to the sum of the feeder link propagation delay and the user link propagation delay (i.e., the propagation delay between the gateway and the terminal equipment via the satellite). The round-trip time delay can be equated to the delay along the path gateway-satellite-user equipment-satellite gateway, and is twice the one-way propagation delay.

[0040] As used herein, a satellite-based network access node can refer to a satellite that performs functions higher than those of a satellite access node. A satellite-based network access node can have a regenerative payload, enabling it to process, demodulate, and regenerate signals before forwarding them to the core network or user equipment. A satellite-based network access node can be considered a standalone base station. A satellite-based network access node can perform base station-like functions, such as managing radio resources, scheduling transmissions, and handling user equipment mobility management. In the context of cellular communications, a satellite-based network access node can be a satellite that acts as a gNB (e.g., a satellite gNB) in a non-terrestrial network architecture, providing direct access to user equipment without requiring an intermediate terrestrial gateway. Note that in this configuration, the one-way propagation delay can correspond to the propagation delay between the satellite and the user equipment. The round-trip time delay can correspond to the delay along the path from satellite to user equipment to satellite.

[0041] The apparatuses and methods described herein may utilize or relate to wireless communication technologies. While some examples may relate to specific wireless communication technologies, the examples provided herein can be similarly applied to a variety of other wireless communication technologies (both existing and undeveloped), particularly where such wireless communication technologies share similar features as disclosed with respect to the examples below. Various exemplary wireless communication technologies that may be utilized by the apparatuses and methods described herein include, but are not limited to: Global System for Mobile Communications (“GSM”) wireless communication technology, General Packet Radio Service (“GPRS”) wireless communication technology, Enhanced GSM Evolution Data Rate (“EDGE”) wireless communication technology and / or 3rd Generation Partnership Project (“3GPP”) wireless communication technologies, such as Universal Mobile Telecommunications System (“UMTS”), Freedom of Multimedia Access (“FOMA”), 3GPP Long Term Evolution (“LTE”), and 3GPP Long Term Evolution Enhanced (“LTE”). Advanced), Code Division Multiple Access 2000 (“CDMA2000”), Cellular Digital Packet Data (“CDPD”), Mobitex, 3rd Generation (3G), Circuit Switched Data (“CSD”), High-Speed ​​Circuit Switched Data (“HSCSD”), Universal Mobile Telecommunications System (“3rd Generation”) (“UMTS(3G)”), Wideband Code Division Multiple Access (“W-CDMA(UMTS)”), High-Speed ​​Packet Access (“HSPA”), High-Speed ​​Downlink Packet Access (“HSDPA”), High-Speed ​​Uplink Packet Access (“HSUPA”), High-Speed ​​Packet Access Enhanced (“HSPA+”), Universal Mobile Telecommunications System Time Division Duplex (“UMTS Time Division Duplex”), Time Division Code Division Multiple Access (“TD-CDMA”), Time Division Synchronous Code Division Multiple Access (“TD-CDMA”), 3GPP Rel.8 (Pre-4G) (“3GPP Rel.8(Pre-4G)”), 3GPP Rel.9 (3GPP Rel.9), 3GPP 3GPP Rel.10 (3rd Generation Partnership Project Version 10), 3GPP Rel.11 (3rd Generation Partnership Project Version 11), 3GPP Rel.12 (3rd Generation Partnership Project Version 12), 3GPP Rel.13 (3rd Generation Partnership Project Version 13), 3GPP Rel.14 (3rd Generation Partnership Project Version 14), 3GPP Rel.15 (3rd Generation Partnership Project Version 15), 3GPP Rel.16 (3rd Generation Partnership Project Version 16), 3GPP Rel.17 (3rd Generation Partnership Project Version 17), 3GPP Rel.18 (3rd Generation Partnership Project Version 18), 3GPP 4G, 3GPP LTEExtra, LTE-Advanced Pro, LTE Licensed Assisted Access (“LAA”), MuLTEfire, UMTS Terrestrial Radio Access (“UTRA”), Evolved UMTS Terrestrial Radio Access (“E-UTRA”), Long Term Evolution Enhanced (4th Generation) (“LTE Advanced (4G)”), cdmaOne (“2G”), Code Division Multiple Access 2000 (3rd Generation) (“CDMA2000 (3G)”), Evolved Data Optimized or Evolved Data Only (“EV-DO”), Advanced Mobile Phone Systems (1st Generation) (“AMPS (1G)”), Total Access Communications Deployment / Extended Total Access Communications Deployment (“TACS / ETACS”), Digital AMPS (2nd Generation) (“D-AMPS (2G)”), Push-to-Talk (“PTT”), Mobile Phone Systems (“MTS”), Improved Mobile Phone Systems (“IMTS”), Advanced Mobile Phone Systems (“AMTS”), OLT (Norwegian: Offentlig) Landmobil Telefoni (Public Land Mobile Phone), MTD (Swedish abbreviation: Mobiltelefonisystem D, or Mobile Telephone System D), Public Automatic Land Mobile (“Autotel / PALM”), ARP (Finnish: Autoradiopuhelin, “Vehicle Radiophone”), NMT (Nordic Mobile Phone), NTT High Capacity Version (Japan Telegraph and Telephone) (“Hicap”), Cellular Digital Packet Data (“CDPD”), Mobilex, DataTAC, Integrated Digital Enhanced Network (“iDEN”), Personal Digital Cellular (“PDC”), Circuit Switched Data (“CSD”), Personal Handheld Telephone System (“PHS”), Broadband Integrated Digital Enhanced Network (“WiDEN”), iBurst, Unlicensed Mobile Access (“UMA”) (also known as 3GPP Universal Access Network or GAN standard), Zigbee, etc. The Wireless Gigabit Alliance (“WiGig”) standard, common millimeter-wave standards (wireless systems operating in the 10GHz-300GHz and above range, such as WiGig, IEEE 802.11ad, IEEE 80.11ay, etc.), technologies operating in the 300GHz and THz bands and above, vehicle-to-vehicle (“V2V”) and vehicle-to-X (“V2X”) and vehicle-to-infrastructure (“V2I”) and infrastructure-to-vehicle (“I2V”) communication technologies (based on 3GPP / LTE or IEEE 802.11p and others), 3GPP cellular V2X, DSRC (Dedicated Short Range Communication) communication deployments, such as intelligent transportation systems, and other existing, developing or future wireless communication technologies.

[0042] The apparatus and methods described herein can utilize this wireless communication technology according to various spectrum management schemes (including, but not limited to, dedicated licensed spectrum, unlicensed spectrum, and (licensed) shared spectrum (such as LSA = licensed shared access at frequencies of 2.3 GHz-2.4 GHz, 3.4 GHz-3.6 GHz, 3.6 GHz-3.8 GHz and further, and SAS = spectrum access system at frequencies of 3.55 GHz-3.7 GHz and further)) and can use various spectrum bands, including but not limited to IMT (International Mobile Telecommunications) spectrum (including 450 MHz-470 MHz, 690 MHz-960 MHz). 0MHz, 1710MHz-2025MHz, 2110MHz-2200MHz, 2300MHz-2400MHz, 2500MHz-2690MHz, 698MHz-790MHz, 610MHz-790MHz, and 3400MHz-3600MHz, etc. (some of which may be restricted to specific regions and / or countries), IMT-Advanced Spectrum, IMT-2020 Spectrum (expected to include the 3600MHz-3800MHz band, the 3.5GHz band, the 600MHz band, and bands in the 24.25GHz-86GHz range, etc.), in FC The spectrum available under C's "Spectrum Frontier" 4G initiative (including 27.5GHz-28.35GHz, 29.1GHz-29.25GHz, 31GHz-31.3GHz, 37GHz-38.6GHz, 38.6GHz-40GHz, 42GHz-42.5GHz, 47GHz-64GHz, 64GHz-71GHz, 61GHz-76GHz, 81GHz-86GHz, and 92GHz-94GHz, etc.), 4.9GHz (typically 4.85GHz-5.925GHz), and 63GHz-64GHz for ITS (Intelligent Transportation Systems) Frequency bands, currently allocated to WiGig (such as WiGig band 1 (57.24GHz-59.40GHz), WiGig band 2 (59.40GHz-61.56GHz), WiGig band 3 (61.56GHz-63.72GHz), and WiGig band 4 (63.72GHz-65.88GHz)), the 60.2GHz-71GHz band, any band between 65.88GHz and 61GHz, currently allocated to automotive radar applications (such as 66GHz-81GHz), and future bands including 94GHz-300GHz and above. Furthermore, the apparatus and methods described herein are also capable of employing secondary wireless communication technologies in bands such as TV blank bands (typically below 690MHz), in which, for example, the 400MHz and 600MHz bands are anticipated candidate bands.Beyond cellular applications, it can also address specific applications in vertical markets such as PMSE (Programming and Special Events), medical, health, surgical, automotive, low-latency, and drone applications. Furthermore, the apparatus and methods described herein can utilize wireless communication technologies with hierarchical applications, such as introducing hierarchical priority (e.g., low / medium / high priority, etc.) for different types of users based on priority access to the spectrum (e.g., highest priority for Tier 1 users, then Tier 2, Tier 3, etc.). The apparatus and methods described herein are also capable of using wireless communication technologies with different single-carrier or orthogonal frequency division multiplexing (OFDM) characteristics (CP OFDM, SC-FDMA, SC OFDM, filter bank-based multicarrier (FBMC), OFDMA, etc.) and, for example, 3GPP NR (New Radio), which can include allocating OFDM carrier data bit vectors to corresponding symbol resources.

[0043] Wireless communication technologies can be categorized into either short-range wireless communication technologies or cellular wide-area wireless communication technologies. Short-range wireless communication technologies can include Bluetooth, WLAN (e.g., according to any IEEE 802.11 standard), and other similar wireless communication technologies. Cellular wide-area wireless communication technologies can include Global System for Mobile Communications (“GSM”), Code Division Multiple Access 2000 (“CDMA2000”), Universal Mobile Telecommunications System (“UMTS”), Long Term Evolution (“LTE”), General Packet Radio Service (“GPRS”), Evolved Data Optimized (“EV-DO”), Enhanced GSM Evolution Data Rate (“EDGE”), High Speed ​​Packet Access (HSPA: including High Speed ​​Downlink Packet Access (“HSDPA”), High Speed ​​Uplink Packet Access (“HSUPA”), HSDPA Enhanced (“HSDPA+”), and HSUPA Enhanced (“HSUPA+”)), Global Microwave Access Interoperability (“WiMax”) (e.g., according to the IEEE 802.16 wireless communication standard, such as WiMax Fixed or WiMax Mobile), and other similar wireless communication technologies. Cellular wide-area wireless communication technology also includes "small cells" of this technology, such as microcells, femtocells, and picocells. In this article, cellular wide-area wireless communication technology will generally be referred to as "cellular" communication technology.

[0044] Figure 1 and Figure 2 A general network and device architecture for wireless communication and / or sensing operations is described. Specifically, Figure 1An exemplary wireless communication network 100 is illustrated according to some aspects. The exemplary wireless communication network 100 may include terminal devices 102 and 104, and network access nodes 110 and 120 (e.g., wireless access nodes). The wireless communication network 100 can communicate with terminal devices 102 and 104 via network access nodes 110 and 120 through a wireless access network. Each of terminal devices 102 and 104, or network access nodes 110 and 120, may be a sensing communication device capable of performing sensing operations as described herein. Although some examples described herein may refer to a specific wireless access network context (e.g., 6G, 5G NR, LTE, UMTS, GSM, other 3GPP networks, WLAN / WiFi, Bluetooth, millimeter wave, etc.), these examples are illustrative and can therefore be readily applied to any other type or configuration of wireless access network. The number of network access nodes and terminal devices in the wireless communication network 100 is exemplary and can be scaled to any quantity.

[0045] In an exemplary cellular context, network access node 110 and network access node 120 may be base stations (e.g., eNodeB, NodeB, Base Transceiver Station (BTS), gNodeB, or any other type of base station), while terminal device 102 and terminal device 104 may be cellular terminal devices (e.g., mobile station (MS), user equipment (user equipment), or any type of cellular terminal device). Therefore, network access node 110 and network access node 120 may (e.g., via a backhaul interface) connect to a cellular core network (such as an evolved packet core (EPC for LTE), a core network (CN for UMTS), or other cellular core networks), which may also be considered part of the wireless communication network 100. The cellular core network may connect to one or more external data networks.

[0046] Network access node 110 and network access node 120 (and optionally, in Figure 1 Other network access nodes of the wireless communication network 100 (not explicitly shown) can correspondingly provide information to terminal device 102 and terminal device 104 (and optionally, in...). Figure 1Other terminal devices (not explicitly shown in the diagram) of the wireless communication network 100 are provided with wireless access networks. In an exemplary cellular context, the wireless access networks provided by network access nodes 110 and 120 enable terminal devices 102 and 104 to wirelessly access the core network via wireless communication. The core network can provide exchange, routing, and transmission of service data associated with terminal devices 102 and 104, and can also provide access to various internal data networks (e.g., control nodes, routing nodes that transmit information between other terminal devices on the wireless communication network 100, etc.) and external data networks (e.g., data networks that provide voice, text, multimedia (audio, video, images), and other Internet and application data). Furthermore, terminal devices 102 and 104, as well as network access nodes 110 and 120, can perform sensing operations, particularly radar sensing, according to a Joint Communications and Sensing (JCAS) architecture. In an exemplary short-range context, the wireless access network provided by network access node 110 and network access node 120 can provide access to internal data networks (e.g., for transmitting data between terminal devices connected to wireless communication network 100) and external data networks (e.g., data networks providing voice, text, multimedia (audio, video, images), and other Internet and application data).

[0047] According to the various aspects described herein, network access nodes 110 and 120, as well as terminal devices 102 and 104, perform their respective sensing operations in a manner such that each device can perform its respective sensing operation based on its respective sensing signal configuration. Therefore, each of these devices can generate and transmit its respective sensing signal according to its respective configuration, which may include at least one of the following: frequency resources for transmitting the sensing signal, bandwidth of the sensing signal, transmission power of the sensing signal, and waveform shape of the sensing signal, which the respective device can determine before generating and / or transmitting the sensing signal. In some examples, a central orchestrator (e.g., a sensing orchestrator) can determine a respective sensing signal configuration for each device and send information representing the respective sensing information configuration to the respective devices.

[0048] The radio access network and core network of wireless communication network 100 (if available, such as for cellular contexts) can be managed by a communication protocol that can vary depending on the details of wireless communication network 100. This communication protocol can define the scheduling, formatting, and routing of both user data services and control data services through wireless communication network 100, including transmitting and receiving such data through both the radio access network domain and the core network domain of wireless communication network 100. Therefore, terminal devices 102 and 104, as well as network access nodes 110 and 120, can follow the defined communication protocol to transmit and receive data on the radio access network domain of wireless communication network 100, while the core network can follow the defined communication protocol to route data within and outside the core network. Exemplary communication protocols include 6G, 5G NR, LTE, UMTS, GSM, WiMAX, Bluetooth, WiFi, millimeter wave, etc., any one of which can be applied to wireless communication network 100.

[0049] In various aspects, network access node 110 and network access node 120 may include one or more central units (CUs), one or more distribution units (DUs), and one or more radio units (RUs) to communicate with terminal devices 102 and 104. In various examples, the radio unit may include devices configured to implement various processing functions for RF. Specifically, the RU may implement lower PHY functions. The DU may include devices configured to implement various processing functions, particularly including higher PHY, MAC, and RLC functions. Those skilled in the art will recognize that this is an example of a split network stack, and that the DU and RU may have different split configurations. The RU may be wirelessly linked to terminal devices 102 and 104 and linked to the DU via a fronthaul interface. In various examples, the fronthaul interface may be a Common Public Radio Interface (CPRI) or an enhanced Common Public Radio Interface (eCPRI) configured for communication via fiber optic cable, but other communication media capable of handling fronthaul communication are also possible. In any case, the RU may serve multiple terminal devices, and there may be limitations regarding the link capacity and bandwidth of communication between the RU and the corresponding DU via fronthaul. Addressing some of the limitations of the prequel is to be expected.

[0050] Figure 2Exemplary internal configurations of a communication device (e.g., a sensing communication device) are shown according to various aspects. The communication device may include aspects of a wireless communication device (e.g., network access node 110, network access node 120) or similarly, aspects of a mobile wireless communication device (e.g., terminal device 102, terminal device 104). Communication device 200 may include an antenna system 202, a radio frequency (RF) transceiver 204, a baseband modem 206 (including a digital signal processor 208 and a protocol controller 210), an application processor 212, and a memory 214. Although in Figure 2 Not explicitly shown, but in some respects, the communication device 200 may include one or more additional hardware components and / or software components, such as processors / microprocessors, controllers / microcontrollers, other dedicated or general-purpose hardware / processors / circuits, (multiple) peripheral devices, memory, power supply, (multiple) external device interfaces, (multiple) user identity modules (SIMs), user input / output devices ((multiple) displays, (multiple) keyboards, (multiple) touchscreens, (multiple) speakers, (multiple) external buttons, (multiple) cameras, (multiple) microphones, etc.) or other related components.

[0051] Communication device 200 can transmit and receive wireless signals over one or more wireless access networks. Baseband modem 206 can direct this communication function of communication device 200 according to the communication protocol associated with each wireless access network, and can control antenna system 202 and RF transceiver 204 to transmit and receive wireless signals according to formatting and scheduling parameters defined by each communication protocol. Although various practical designs may include separate communication components (e.g., separate antennas, RF transceivers, digital signal processors, and controllers) for each supported wireless communication technology, for the sake of brevity, Figure 2 The configuration of the communication device 200 shown in the figure only depicts a single instance of such a component.

[0052] Communication device 200 can use antenna system 202 to transmit and receive wireless signals. Antenna system 202 can be a single antenna or can include one or more antenna arrays, each comprising multiple antenna elements. For example, antenna system 202 can include an antenna array at the top of communication device 200 and a second antenna array at the bottom of communication device 200. In some aspects, antenna system 202 may additionally include analog antenna combination and / or beamforming circuitry. In the receive (RX) path, RF transceiver 204 can receive analog radio frequency signals from antenna system 202 and perform analog and digital RF front-end processing on the analog radio frequency signals to generate digital baseband samples (e.g., in-phase / quadrature (IQ) samples), which are then provided to baseband modem 206. RF transceiver 204 may include analog and digital receiving components, including amplifiers (e.g., low-noise amplifiers (LNAs)), filters, RF demodulators (e.g., RF IQ demodulators), and analog-to-digital converters (ADCs). RF transceiver 202 may utilize amplifiers (e.g., LNAs), filters, RF demodulators (e.g., RF IQ demodulators), and ADCs to convert received radio frequency signals into digital baseband samples. In the transmit (TX) path, RF transceiver 204 may receive digital baseband samples from baseband modem 206 and perform analog and digital RF front-end processing on the digital baseband samples to generate analog radio frequency signals, which are then provided to antenna system 202 for wireless transmission. Therefore, RF transceiver 204 may include analog and digital transmission components, including amplifiers (e.g., power amplifiers (PAs), filters, RF modulators (e.g., RF IQ modulators), and digital-to-analog converters (DACs). RF transceiver 204 may utilize the amplifiers (e.g., power amplifiers (PAs), filters, RF modulators (e.g., RF IQ modulators), and DACs to mix digital baseband samples received from baseband modem 206 and generate analog radio frequency signals for wireless transmission through antenna system 202. In some aspects, baseband modem 206 may control the wireless transmission and reception of RF transceiver 204, including specifying the transmit and receive radio frequencies for the operation of RF transceiver 204.

[0053] Based on the various aspects provided herein, communication device 200 can perform sensing operations within wireless communication network 100. Illustratively, baseband modem 206 (e.g., digital signal processor 208) can be configured to perform sensing-related signal processing in addition to performing conventional communication processing. For example, baseband modem 206 can be configured to implement techniques such as radar waveform generation, matched filtering for target detection, parameter estimation (e.g., range, velocity, angle) for target detection, and environment mapping. In some examples, baseband modem 206 (e.g., digital signal processor 208) can use its hardware accelerators and parallel processing capabilities to efficiently handle computationally intensive sensing algorithms and communication tasks.

[0054] Furthermore, the baseband modem 206 (e.g., protocol controller 210) can be configured to coordinate and / or manage the joint operation of communication and sensing functions. Illustratively, the baseband modem 206 can schedule sensing and communication operations, allocate resources (e.g., time / frequency resources, antenna beams) between sensing and communication operations, and manage interference between sensing and communication operations. The baseband modem (e.g., protocol controller 210) can also implement sensing control protocols and interfaces to enable coordination with other network entities for distributed sensing operations as described herein.

[0055] In some examples, application processor 212 can be configured to act as a source and sink for sensed data, similar to its role with communication data. Application processor 212 can execute sensing applications configured to process and interpret sensed data received from baseband modem 206. Illustratively, application processor 212 can use the sensed data to perform at least one of object detection and tracking, environment mapping, and / or situational awareness services. In some examples, application processor 212 can connect to external sensors (e.g., cameras, LiDAR) to fuse data from multiple sensing modalities, thereby enhancing sensing capabilities.

[0056] Accordingly, in addition to communication signals, RF transceiver 204 can also support the transmission and reception of sensed waveforms. Illustratively, RF transceiver 204 can generate and transmit sensed signals (e.g., frequency-modulated continuous waveforms for radar) and can process received sensed signals to extract target information. In some examples, RF transceiver 204 can use the same analog and digital components (e.g., amplifiers, filters, modulators / demodulators, ADCs / DACs) for both sensing and communication operations, possibly with additional hardware accelerators for sensing-specific tasks. Illustratively, in some examples with a separate antenna array or a shared array with beamforming capabilities, antenna system 202 can also support both communication and sensing functions. Depending on various aspects, antenna system 202 can form a narrow beam for extended sensing range or a wide beam for faster coverage, depending on sensing requirements and resource constraints. Techniques such as multiple-input multiple-output (MIMO) and beamforming can be employed to enhance sensing performance and achieve features such as high-resolution target parameter estimation and interference suppression.

[0057] As in Figure 2As shown, the baseband modem 206 may include a digital signal processor 208, which can perform physical layer (PHY, Layer 1) transmit and receive processing to prepare outgoing transmit data provided by the protocol controller 210 for transmission via the RF transceiver 204 in the transmit path, and to prepare incoming receive data provided by the RF transceiver 204 for processing by the protocol controller 210 in the receive path. The digital signal processor 208 may be configured to perform one or more of the following physical layer processing functions: error detection, forward error correction coding / decoding, channel coding and interleaving, channel modulation / demodulation, physical channel mapping, radio measurement and search, frequency and time synchronization, antenna diversity processing, power control and weighting, rate matching / dematching, retransmission processing, interference cancellation, and any other physical layer processing functions. Digital signal processor 208 may be structurally implemented as a hardware component (e.g., as one or more digitally configured hardware circuits or field-programmable gate arrays (FPGAs)), a software-defined component (e.g., one or more processors configured to execute program code (e.g., software and / or firmware) defining arithmetic, control, and I / O instructions stored in a non-transitory computer-readable storage medium), or a combination of hardware and software components. In some aspects, digital signal processor 208 may include one or more processors configured to retrieve and execute program code defining control and processing logic for physical layer processing operations. In some aspects, digital signal processor 208 may perform processing functions in software via the execution of executable instructions. In some aspects, digital signal processor 208 may include one or more dedicated hardware circuits (e.g., application-specific integrated circuits (ASICs), field-programmable gate arrays, and other hardware) digitally configured to perform specific processing functions, wherein one or more processors of digital signal processor 208 may offload certain processing tasks to these dedicated hardware circuits, referred to as hardware accelerators. Exemplary hardware accelerators may include Fast Fourier Transform (FFT) circuitry and encoder / decoder circuitry. In some respects, the processor and hardware accelerator components of the digital signal processor 208 can be implemented as coupled integrated circuits.

[0058] Communication device 200 can be configured to operate according to one or more wireless communication technologies. Digital signal processor 208 can handle lower-layer processing functions (e.g., layer 1 / PHY) of the wireless communication technology, while protocol controller 210 can handle upper-layer protocol stack functions (e.g., data link layer / layer 2 and / or network layer / layer 3). Therefore, protocol controller 210 can be responsible for controlling the wireless communication components of communication device 200 (antenna system 202, RF transceiver 204, and digital signal processor 208) according to the communication protocol of each supported wireless communication technology, and thus can represent the access layer and non-access layer (NAS) (including layers 2 and 3) of each supported wireless communication technology. Protocol controller 210 can be structurally implemented as a protocol processor configured to execute protocol stack software (retrieved from controller memory) and subsequently control the wireless communication components of communication device 200 to transmit and receive communication signals according to the corresponding protocol stack control logic defined in the protocol software. Protocol controller 210 may include one or more processors configured to retrieve and execute program code defining upper-layer protocol stack logic for one or more wireless communication technologies. This upper-layer protocol stack logic may include data link layer / layer 2 functions and network layer / layer 3 functions. Protocol controller 210 may be configured to perform both user plane functions and control plane functions according to the specific protocol of the supported wireless communication technology to facilitate the transfer of application layer data to and from wireless communication device 200. User plane functions may include header compression and encapsulation, security, error checking and correction, channel multiplexing, scheduling and prioritization, while control plane functions may include the setup and maintenance of radio bearers. The program code retrieved and executed by protocol controller 210 may include executable instructions defining the logic of such functions.

[0059] The communication device 200 may also include an application processor 212 and a memory 214. The application processor 212 may be a central processing unit and may be configured to process layers above the protocol stack, including the transport layer and the application layer. The application processor 212 may be configured to execute various applications and / or programs of the communication device 200 at the application layer of the communication device 200 (such as an operating system (OS), a user interface (UI) for supporting user interaction with the communication device 200, and / or various user applications). The application processor may be connected to the baseband modem 206 and act as a source (in the transmit path) and sink (in the receive path) for user data (such as voice data, audio / video / image data, message data, application data, basic Internet / network access data, etc.). Therefore, in the transmit path, the protocol controller 210 may receive and process outgoing data provided by the application processor 212 according to the layer-specific functions of the protocol stack and provide the resulting data to the digital signal processor 208. Then, the digital signal processor 208 can perform physical layer processing on the received data to generate digital baseband samples, which can then be provided to the RF transceiver 204. The RF transceiver 204 can then process the digital baseband samples to convert them into analog RF signals, which can then be wirelessly transmitted via the antenna system 202. In the receiving path, the RF transceiver 204 can receive the analog RF signals from the antenna system 202 and process them to obtain digital baseband samples. The RF transceiver 204 can then provide the digital baseband samples to the digital signal processor 208, which can perform physical layer processing on the digital baseband samples. The digital signal processor 208 can then provide the resulting data to the protocol controller 210, which can process the resulting data according to the layer-specific functions of the protocol stack and then provide the resulting data to the application processor 212. Then, the application processor 212 can process the introduced data at the application layer, which can include executing one or more applications with the data and / or presenting the data to the user via a user interface.

[0060] Memory 214 may embody the memory component of communication device 200, such as a hard disk drive or another such permanent storage device. Although in Figure 2 It is not explicitly described in the text, but in Figure 2 Various other components of the communication device 200 shown may additionally include integrated permanent and non-permanent memory components, such as those for storing software program code, buffered data, etc.

[0061] According to some wireless communication networks, terminal devices 102 and 104 can perform mobility procedures to connect to, disconnect from, and switch between available network access nodes of the wireless access network of wireless communication network 100. Since each network access node of wireless communication network 100 can have a specific coverage area, terminal devices 102 and 104 can be configured to select and reselect available network access nodes to maintain a strong wireless access connection with the wireless access network of wireless communication network 100. For example, terminal device 102 can establish a wireless access connection with network access node 110, while terminal device 104 can establish a wireless access connection with network access node 112. In the event of a deterioration of the current wireless access connection, terminal device 102 or terminal device 104 can seek a new wireless access connection with another network access node of wireless communication network 100. For example, terminal device 104 can move from the coverage area of ​​network access node 112 to the coverage area of ​​network access node 110. Therefore, the wireless access connection with network access node 112 may degrade, and terminal device 104 can detect the degradation via wireless measurements such as signal strength or signal quality measurements of network access node 112. According to the mobility procedures defined in the appropriate network protocol for wireless communication network 100, terminal device 104 can determine whether any adjacent network access node can provide a suitable wireless access connection, such as by performing wireless measurements on adjacent network access nodes, and seek a new wireless access connection (e.g., triggered at terminal device 104 or by the wireless access network). Since terminal device 104 may have moved to the coverage area of ​​network access node 110, terminal device 104 can identify network access node 110 (which may be selected by terminal device 104 or by the wireless access network) and proceed to a new wireless access connection with network access node 1100. This mobility process (including wireless measurements, cell selection / reselection, and handover) is established in various network protocols and can be adopted by terminal devices and wireless access networks to maintain a strong wireless access connection between each terminal device and the wireless access network across any number of different wireless access network scenarios.

[0062] Figure 3 Illustrative examples of apparatuses according to various aspects described herein are shown. A communication device (e.g., communication device 200) configured to operate as a network access node as described herein may include device 300, which may illustratively be a satellite-based network access node or a satellite access node. Illustratively, the communication device may be network access node 110, network access node 120, or terminal device 102 or terminal device 104.

[0063] The device 300 may include a processor 301, a memory 302, and a communication interface 303 configured to receive and transmit communication signals for communication with further entities within a wireless access network. In some aspects, the communication interface 303 may include one or more signal paths carrying the communication signals. The communication interface 303 may include one or more transceivers. In some examples, the communication interface 303 may also be configured to transmit sensing signals and receive reflected sensing signals, as described herein.

[0064] Processor 301 may include one or more processors, which may include a baseband processor and an application processor (e.g., application processor 212, baseband modem 206). In various examples, processor 301 may include a central processing unit, a graphics processing unit, a hardware acceleration unit (e.g., one or more dedicated hardware accelerator circuits (e.g., application-specific integrated circuits, field-programmable gate arrays, and other hardware)), a neuromorphic chip, and / or a controller. Processor 301 may be implemented in a processing unit (e.g., a system-on-a-chip (SOC) or a processor). According to various examples, processor 301 may also provide further functionality to process received communication signals. Memory 302 may store various types of information required for the operation of processor 301 or communication interface 303 according to the aspects described herein.

[0065] In some examples, while communication devices may provide communication and / or sensing services within their respective coverage areas, communication interface 303 may be configured to communicate with multiple further communication devices (e.g., further wireless access nodes and / or user equipment), each configured to provide communication or sensing services within its respective coverage area. For example, device 300 may receive information from each of the multiple further communication devices via communication interface 303, some of which are described herein. For example, as described herein, device 300 may provide instructions to each of the multiple further communication devices via communication interface 303. Illustratively, communication interface 303 may include a transceiver (e.g., RF transceiver 204) configured to transmit or receive wireless communication signals.

[0066] Figure 4An example of a satellite communication system with a service link and a feeder link, illustrating various aspects described herein, is shown. The satellite communication system may illustratively include a non-terrestrial network. The system may include a network access node containing device 300. The system may include a satellite 401 positioned in space. In some examples, satellite 401 may act as a network access node, thereby facilitating communication between ground equipment and ground stations. In some examples, ground station 402 may act as a network access node, thereby facilitating communication with ground equipment via satellite 401. Ground station 402 may illustratively include a non-terrestrial network gateway. Satellite 401 may be a satellite access node and / or a satellite-based network access node. Ground station 402 may relay data between satellite 401 and the core network. Ground station 403 may communicate with satellite 401 via feeder link 411. The feeder link may refer to a wireless link between ground station 402 and satellite 401.

[0067] Network access nodes for satellite 401 and / or ground station 402 can provide network access services to multiple terminal devices 403-405 regarding coverage area 406 via their respective service links connecting the satellite to terminal devices 403-405. In some examples, a relay station can be provided as a relay ground station, and network access services can also be provided to terminal devices 403-405 via the relay ground station. Service link 412 can facilitate bidirectional communication between terminal device 403 and satellite 401. Terminal devices 403-405 may include user equipment 403, 405 and / or a very small aperture terminal 404 that can act as an intermediary (i.e., a relay ground station) for local user equipment. Satellite 401 can provide network access services at different locations within coverage area 406 using different beam patterns.

[0068] Note that processor 301 can be a processor of satellite 401 or ground station 402 as described herein, and processor 301 can manage multiple beams covering different parts of coverage area 406. Processor 301 can employ beamforming techniques to optimize resource allocation across coverage area 406. For example, processor 301 can allocate more resources to areas with higher service demands by adjusting the beam pattern accordingly. Additionally, processor 301 can implement frequency reuse techniques to improve spectral efficiency and maximize throughput by allowing different beams to reuse frequencies without causing interference.

[0069] Processor 301 can manage communication between satellite 401 or ground station 402 and terminal devices 403-405 via service link 412. Processor 301 can utilize radio resources by employing a scheduling algorithm that allocates time, frequency, and power resources for communication among terminal devices 403-405. In some examples, the scheduling algorithm may receive information such as channel conditions, traffic demands, and Quality of Service (QoS) requirements for each terminal device. Processor 301 can be configured to execute either or both of a transparent architecture and a regenerative architecture within the satellite communication system. In a transparent architecture, processor 301 can operate with minimal signal processing, simply forwarding signals between terminal devices 403-405 and ground station 402 without decoding or re-encoding the signals. In a regenerative architecture, processor 301 can decode the introduced signals, process the introduced signals on-board, and re-encode the introduced signals before forwarding them to their destination.

[0070] In a first aspect, processor 301 facilitates time-division duplex communication by determining and managing the communication patterns between network access nodes (e.g., satellite 401 or ground station 402) and terminal devices. Processor 301 can determine the time-division duplex communication pattern, which may include multiple time slots allocated for uplink and / or downlink communication. Processor 301 can dynamically adjust the time-division duplex communication pattern based on factors such as service demands, channel conditions, and quality of service requirements. For example, if there is a high demand for downlink data (e.g., streaming services), processor 301 can allocate more time slots for downlink communication. Additionally, processor 301 can manage the allocation of time slots for each terminal device, thereby ensuring efficient use of radio resources. Processor 301 can schedule uplink and downlink transmissions accordingly to minimize interference and maximize throughput.

[0071] Once a time-division duplex communication mode, which may include time slots for alternating uplink and downlink transmissions, is determined, processor 301 can allocate specific time slots to network access nodes to perform uplink or downlink operations. For example, during a downlink time slot, processor 301 can instruct the network access node to transmit data to a terminal device via the serving link. Communication interface 303 can facilitate downlink transmission by modulating downlink communication signals and transmitting them from the network access node to the terminal device. Conversely, during an uplink time slot, processor 301 can schedule a receive window for incoming downlink communication signals from the terminal device. Communication interface 303 can receive these signals via the serving link and demodulate them for further processing.

[0072] Additionally, processor 301 can instruct the terminal device to align its transmit and receive schedules according to this time-division duplex communication mode. Processor 301 can achieve this alignment by scheduling the terminal device according to the determined time-division duplex communication mode through sending specific instructions to the terminal device. Once processor 301 establishes a time-division duplex communication mode that may include alternating time slots for uplink and downlink transmissions, processor 301 can ensure that both the network access node and the terminal device are synchronized within their respective communication windows. According to the various aspects described herein, processor 301 can maintain synchronization by scheduling time slots in which the scheduling device (e.g., one of the network access node or terminal devices) neither performs uplink communication toward another device (i.e., another network access node or terminal device) nor downlink communication toward another device (i.e., another network access node or terminal device). Processor 301 can also convey these allocations to the terminal device via control signals transmitted over the serving link. Processor 301 can encode information indicating allocations (i.e., scheduling) for transmission to the terminal device.

[0073] Processor 301 can allocate first time slots from multiple time slots in a time-division duplex communication mode for uplink or downlink communication between the network access node and the terminal device. These first time slots are designated for the network access node to actively transmit or receive communications with the terminal device. Additionally, processor 301 can allocate multiple second time slots during which the network access node is scheduled not to perform either uplink or downlink communication with the terminal device. The number of second time slots can be based on round-trip time delay, which accounts for propagation delay between the network access node and the terminal device.

[0074] During these second time slots, although there is no active transmission or reception at the network access node, the terminal device can still perform its respective communication tasks. For example, during the second time slot, the terminal device can receive previously transmitted downlink signals from the network access node, or transmit uplink signals that will be received by the network access node in the subsequent first time slot. This asymmetric allocation ensures that signal propagation delay is taken into account, thereby preventing overlap between the transmission and reception windows.

[0075] The number of second time slots can vary depending on factors such as round-trip time delay and service requirements. In satellite communications with significant propagation delays, more second time slots can be allocated to account for these delays. This scheduling ensures proper synchronization between devices and minimizes interference caused by overlapping transmissions.

[0076] In some examples, during these second time slots, processor 301 can dynamically adjust resource allocation based on real-time conditions such as traffic demand or channel quality. For example, if a terminal device requires additional resources for uplink transmission due to high data demand, the processor can allocate additional second time slots for this purpose. Similarly, if downlink communication requires additional bandwidth, second time slots can be used to facilitate delayed reception at the terminal device. This flexibility allows for efficient use of available resources while maintaining synchronization across multiple devices within the coverage area.

[0077] Processor 301 can also schedule the terminal device to neither perform uplink communication nor downlink communication during at least one of the plurality of first time slots allocated to the network access node (this may be referred to as being "idle" or operating "idle"). It should be emphasized that the allocation of the described time-division duplex communication modes (e.g., first time slots, second time slots) is specifically described as allocations designated for the network access node to transmit downlink signals to or receive uplink signals from the terminal device. Processor 301 can schedule the terminal device to remain idle during at least one or more of the first time slots (i.e., neither uplink transmission nor downlink reception is performed for communication with the network access node), such that no uplink or downlink communication occurs at the terminal device when the network access node actively transmits or receives.

[0078] The number of first time slots that the terminal equipment is scheduled to remain idle during this period can be determined by the processor 301 based on factors such as round-trip time delay. For example, in satellite communications with significant propagation delays, more first time slots can be allocated while the terminal equipment remains idle to account for these delays. In some examples, the number of such idle first time slots can be equal to the number of second time slots allocated similarly based on round-trip time delay. This can facilitate an appropriate balance between the first and second time slots to maintain synchronization between uplink and downlink transmissions. In some examples, the processor 301 can calculate the number of second time slots by dividing the round-trip time delay into the slot duration of a time-division duplex communication mode.

[0079] During at least one of these first time slots when no uplink or downlink communication occurs at the terminal device, the network access node continues its communication tasks (e.g., transmitting downlink signals or receiving uplink signals). The processor 301 can dynamically adjust the allocation of the first and second time slots based on real-time factors such as service demand, channel quality, or quality of service requirements. For example, if the terminal device requires additional resources for uplink transmission due to high data demand, the processor can adjust certain first time slots by reducing idle periods to facilitate active communication. Similarly, if another terminal device within the coverage area requires additional downlink bandwidth, adjustments can be made to optimize resource allocation without affecting synchronization.

[0080] Figure 5 An example timing diagram is shown, illustrating downlink and uplink communication slots for a time-division duplex communication mode used for communication between a network access node (e.g., gNB) and an end device (e.g., user equipment). As illustrated herein, the diagram shows the timing relationship between gNB timing and user equipment timing related to round-trip time delay. The gNB timing row illustrates the illustrated time-division duplex communication mode, which includes 32 time slots (numbered from 0 to 31) in a time-division duplex frame (i.e., a time-division duplex cycle), where each time slot is conventionally allocated for either uplink or downlink (i.e., no free slots). Time slots 0 through 12 are allocated as downlink time slots, and time slots 13 through 31 are allocated as uplink time slots. Each time slot may include a first number of symbols (described as 14 symbols, s00 to s13) having a second number of symbols (described as 2 symbols, s12 to s13) of downlink to uplink protection cycles.

[0081] The UE timing line reflects the corresponding time slots at the UE side. Due to the propagation delay between the UE and the gNB (e.g., half the round-trip time delay), the corresponding time slots are offset relative to the gNB timing. This figure illustrates the propagation delay for a duration of 4 time slots. In other words, when the gNB performs a downlink transmission for time slot 0 between time instance 0 and time instance 1, the UE receives a downlink transmission between time instance 4 and time instance 5 (time slot 0 depicted in the UE timing line).

[0082] This delay prevents the gNB from receiving uplink signals during certain time slots immediately following downlink transmissions, as indicated by the red crosses across specific time slots in the gNB timeline. In other words, given that a single connection (i.e., a link) can exist between the gNB's antenna structure and the user equipment, the gNB cannot receive uplink signals between time slots 13 and 20 because, during a portion of this time period (described as the duration between time instance 13 and time instance 17), the user equipment will still receive downlink signals transmitted by the gNB, and during another portion of this time period (described as the duration between time instance 17 and time instance 21), the user equipment will perform uplink transmissions that will begin arriving at the gNB from time instance 21.

[0083] This can also be described as follows: In the scenario depicted here, where the gNB and user equipment use the same time-division duplex slot format, the gNB cannot receive uplink transmissions while the user equipment is still receiving downlink transmissions, and the gNB cannot send downlink transmissions while waiting for the user equipment's transmissions to complete for a certain duration. Therefore, these periods must be idle, resulting in a spectral efficiency of approximately (time-division duplex period - 2 * round-trip time) / time-division duplex period. This leads to a significant reduction in spectral efficiency. For example, with a time-division duplex period of 10 milliseconds and a round-trip time of 4 milliseconds, only 20% efficiency can be achieved.

[0084] Figure 6 An example timing diagram is illustrated, showing the downlink and uplink communication slots in a time-division duplex communication mode between a network access node (e.g., gNB) and a terminal device (e.g., user equipment) according to the aspects described herein. The diagram highlights the timing relationship between the gNB timing and the user equipment timing, illustrating the round-trip time delay inherent in satellite communications.

[0085] In this illustrative example, the gNB timing line illustrates an illustrative time-division duplex communication mode comprising 20 time slots (numbered from 0 to 19) within a time-division duplex frame (i.e., a time-division duplex cycle), where each time slot is allocated for either uplink, downlink, or idle. An idle cycle indicates that the gNB is scheduled not to perform uplink or downlink communication with user equipment using the connection (i.e., neither uplink reception nor downlink transmission). In this illustrative example, time slots 0 through 7 are allocated as downlink time slots, time slots 8 through 15 are allocated as idle time slots, and time slots 16 through 19 are allocated as uplink time slots. Each time slot may include a first number of symbols (depicted as 14 symbols, s00 through s13) with a second number of symbols (depicted as 2 symbols, s12 and s13) of downlink-to-uplink protection cycles.

[0086] The user equipment-aware gNB timing line diagram illustrates the corresponding time slots in the time-division duplex communication mode of the gNB at the user equipment side, which are offset relative to the gNB timing due to the propagation delay between the user equipment and the gNB (e.g., half the round-trip time delay). The diagram illustrates the propagation delay for a duration of four time slots. In other words, when the gNB performs a downlink transmission for time slot 0 between time instance 0 and time instance 1, the user equipment receives a downlink transmission between time instance 4 and time instance 5 (time slot 0 depicted in the user equipment timing line).

[0087] Traditionally, propagation delay prevents the gNB from receiving uplink signals during certain time slots immediately following downlink transmissions, as indicated by the red crosses across specific time slots in the gNB timeline. In other words, given that a single connection (i.e., a link) can exist between the gNB's antenna configuration and the user equipment, the gNB will not be able to receive uplink signals during time slots 8 through 15. However, in this illustrative example, processor 301 identifies time slots 0 through 7 as downlink time slots and time slots 16 through 19 as uplink time slots, as the first time slots described herein. Processor 301 also identifies time slots 8 through 15 as the second time slots. As can be seen here, the number of second time slots corresponds to twice the propagation delay, which in this example is the round-trip time delay. Note that processor 301 can also use timing advance commands for the scheduling described herein to achieve finer granularity.

[0088] Furthermore, processor 301 can also schedule user equipment to communicate with the gNB as illustrated in the user equipment timing line. As explained herein, note that the second time slot corresponds to a duration defined between the 8th and 16th time instances, during which time processor 301 can schedule user equipment to perform uplink or downlink communication with the gNB when the gNB becomes idle. In this illustrative example, processor 301 schedules user equipment to perform downlink communication between the 8th and 12th time instances and uplink communication between the 12th and 16th time instances. Additionally, processor 301 also schedules user equipment to neither perform uplink nor downlink communication with the gNB between the 16th and 24th time instances.

[0089] This can also be described as follows: by using an asymmetric slot format for user equipment and gNB, system spectral efficiency can be improved. As illustrated herein, the uplink time slot for user equipment is moved immediately following the downlink time slot, thereby enabling earlier uplink transmission. As shown, at the gNB, there is no conflict between downlink transmission and uplink reception. Simultaneously, at the user equipment, there is no conflict between downlink reception and uplink transmission. Under this change, the spectral efficiency is ~ = (time-division duplex period - round-trip time) / time-division duplex period. For example, when the time-division duplex period = 10 milliseconds and the round-trip time = 4 milliseconds, the spectral efficiency is improved to 60%.

[0090] As described herein, processor 301 may allocate a first time slot such that the first time slot includes one or more consecutive downlink time slots (e.g., time slots 0 to 7) and one or more consecutive uplink time slots (e.g., time slots 16 to 19) within a time-division duplex cycle. Furthermore, processor 301 may allocate a second time slot such that a second time slot is provided (i.e., inserted) between these one or more consecutive uplink time slots and these one or more consecutive downlink time slots.

[0091] In some examples, where the aforementioned time-division duplex communication mode belongs to the constellation of the network access node, processor 301 can also generate further time-division duplex communication modes for the terminal devices and encode the further time-division duplex communication modes for transmissions to the terminal devices to schedule the terminal devices as described herein. The further time-division duplex communication modes may include one or more terminal device uplink time slots corresponding to the uplink time slots of the network access node's time-division duplex communication mode. The further time-division duplex communication modes may also include one or more terminal device downlink time slots corresponding to the downlink time slots of the network access node's time-division duplex transmission mode. Similarly, the further time-division duplex communication modes may also include one or more terminal device idle time slots corresponding to the idle time slots of the network access node's time-division duplex communication mode. In this illustrative example, processor 301 configures the time-division duplex communication mode and the further time-division duplex communication mode to schedule the terminal devices based on round-trip time delay, as described herein. Processor 301 can configure both modes based on round-trip time delay.

[0092] Figure 7 An illustrative representation of various delay parameters that a processor (e.g., processor 301) can determine, as described herein, related to round-trip time delays. The figure illustrates different representations of delays that processor 301 can consider for optimizing communication between a network access node and a terminal device. Processor 301 can determine the round-trip time delay based on the location of the terminal device. Processor 301 can determine the location of the terminal device using any known method or the method described herein. In this sense, the figure illustrates the calculation of the round-trip time delay for multiple terminal devices within a coverage area, and how this delay is considered when scheduling communication between a network access node and a terminal device.

[0093] In some examples, processor 301 can determine a common round-trip time delay applicable to multiple terminal devices within a coverage area. This simplifies the delay management process by using a common delay value for these multiple terminal devices. Illustratively, in the illustration, the common round-trip time delay is described as a common minimum delay, and the common round-trip time delay can be the minimum round-trip time delay among those determined for multiple terminal devices. Processor 301 can determine the common round-trip time delay based on the time slot duration. In this case, the common round-trip time delay can be represented by a common minimum delay integer, which represents the smallest integer of time slots required to account for the minimum round-trip time delay. Illustratively, the product of the common minimum delay integer and the time slot duration corresponds to the real-time round-trip time delay. For example, this common round-trip time delay can be shared by multiple terminal devices (e.g., all terminal devices within the coverage area), thereby ensuring that no device experiences a delay shorter than this minimum value. In some examples, processor 301 may use time-of-flight measurements or Doppler offset (or any other method) to calculate the round-trip time delay for each terminal device. Once these delays are determined, processor 301 can select a minimum delay and configure it as the common round-trip time delay for all devices in the coverage area. This facilitates that all devices experience at least this minimum delay, thereby allowing for synchronous communication.

[0094] Furthermore, processor 301 can also determine a further round-trip time delay for each terminal device, which is added to the common round-trip time delay to calculate the total round-trip time delay for each device. This further round-trip time delay can take into account differences in orientation between terminal devices, as described by terms such as maximum user equipment (UE) delay, remaining delay user equipment (UE) delay, and maximum remaining user equipment (UE) delay. In other words, for a terminal device, its round-trip time delay can be represented by a combination (e.g., sum) of the common round-trip time delay and its respective further round-trip time delays (e.g., the remaining delay user equipment or maximum remaining user equipment (UE) delay as described herein). These terms represent the additional delay experienced by an individual terminal device based on its distance from the network access node. In some examples, processor 301 can use orientation-based data (such as GPS coordinates or signal strength measurements) to estimate the respective further round-trip time delay for each terminal device. This further delay is then added to the common round-trip time delay to calculate the total round-trip time for each terminal device. Alternatively or additionally, the processor 302 may estimate the further round-trip time delay using techniques such as signal triangulation or Doppler offset analysis based on signal propagation time or azimuth data from the Global Positioning System.

[0095] In some examples, processor 301 can determine the location of the terminal device based on the round-trip time delay determined for the terminal device. Furthermore, the combination of delay and Doppler offset is unique for each terminal device location. Therefore, by analyzing both delay and Doppler offset, processor 301 can determine the location of the terminal device in view of the location of the network access node. In some examples, processor 301 can estimate further round-trip time delays (or the total round-trip time delay of the terminal device) based on physical random access channel transmissions received from the terminal device. Processor 301 can then encode a random access message for transmission of a random access response, wherein the timing advance value in the random access response is based on the estimated round-trip time delay.

[0096] Illustratively, processor 301 may first receive a Physical Random Access Channel (PRAN) preamble transmitted by a terminal device, which the terminal device uses to initiate communication with a network access node. Upon receiving such a PRAN transmission, processor 301 may begin estimating the round-trip time (RTT) delay, as described herein. In some examples, processor 301 may monitor the service link used to introduce the PRAN from the terminal device. Upon detecting a PRAN transmission, processor 301 may record the arrival time of the signal and begin calculating the propagation delay. Once a PRAN transmission is received, processor 301 may estimate the respective further RTT delay for the terminal device. This further RTT delay represents any additional propagation delay beyond the common RTT shared by all devices in the coverage area. Processor 301 can estimate this further delay by analyzing the time difference between when the PRAN preamble is transmitted by the terminal device and when it is received at the network access node. Illustratively, processor 301 can use signal propagation measurements (e.g., time of flight) to estimate the time it takes for a physical random access channel signal to travel from the terminal device to the network access node. By comparing this time with a known distance or propagation model, the processor is able to calculate the additional round-trip time delay specific to that terminal device.

[0097] After estimating further round-trip time delays, processor 301 can encode a random access message including a random access response for transmission back to the terminal device. The random access response may include information such as timing synchronization parameters including timing advance values, which adjust the timing of future transmissions from the terminal device to account for propagation delays. Processor 301 can also encode a random access response message including a timing advance value calculated based on a common round-trip time delay for that particular terminal device and its respective further round-trip time delays. The timing advance value in the random access response can be directly based on the two components of the round-trip time delay (the common round-trip time delay shared by all devices and the respective further round-trip time delay specific to each terminal device). By using this timing advance value to adjust transmission timing, future uplink signals from each terminal device can arrive at the network access node synchronously with other devices.

[0098] In the second aspect, processor 301 can determine and track the orientation of one or more terminal devices within the coverage area. According to the various aspects described herein, processor 301 can determine and track the orientation based on various types of reference signals known to both the terminal devices and processor 301 to a certain extent. Although this second aspect can be specifically used for terminal devices in the absence of any Global Positioning System / positioning system like a Global Navigation Satellite System, it can also be used to refine and / or track from a determined orientation, and processor 301 can also use the known location of the terminal device within the coverage area to refine and / or track. Furthermore, although aspects for a single terminal device may have been described herein, device 300 and processor 301 can perform the operations described herein to determine and track the orientation of some or all terminal devices within the coverage area. It should also be noted that although the first and second aspects (each including further, more detailed aspects) have been described herein with respect to a single terminal device, device 300 and processor 301 can perform, individually or simultaneously, the operations described herein relating to the first aspect related to time-division duplex communication mode and the second aspect related to orientation determination.

[0099] In some examples, processor 301 can determine the orientation of a terminal device based on a round-trip time delay determined for the terminal device. The round-trip time delay can represent the time it takes for a signal to travel between the terminal device and a network access node (e.g., a satellite or gNB). Additionally, the combination of round-trip time delay and Doppler offset is unique for each terminal device because both parameters are affected by the relative position and movement of the terminal device relative to the network access node. By analyzing both the round-trip time delay and Doppler offset, processor 301 can estimate the orientation of the terminal device within the coverage area with a certain degree of accuracy. For example, as in... Figure 7 As described, round-trip time delay is calculated using various delay parameters, such as the common minimum delay integer and the residual delay user equipment. Processor 301 can further refine this orientation estimate by analyzing Doppler offset data, which provides insight into the speed and direction of movement of the terminal device relative to the network access node. This combination of round-trip time delay and Doppler offset can allow for precise orientation determination even in non-terrestrial networks where GPS / GNSS data may be unavailable.

[0100] In some aspects, it is desirable to use certain signaling schemes that already exist and are widely used in communication technologies (such as physical random access channel preambles and demodulation reference signals in cellular communications) to determine the location of a terminal device. These signals are known to both the terminal device and the network access node and can be adequately used for location estimation without additional signaling overhead. For example, physical random access channel preambles are typically used for the initial access procedure, but they also provide valuable timing information that allows processor 301 to estimate the round-trip time delay between the terminal device and the network access node. Similarly, the demodulation reference signal embedded in the uplink transmission used for channel estimation can be used to track the relative motion of the terminal device by analyzing Doppler shift. By combining these existing signaling schemes with round-trip time delay measurements, processor 301 can determine and track the location of the terminal device within the coverage area of ​​the network access node.

[0101] Once the location of the terminal device is determined (e.g., initial location), the processor 301 can configure the uplink transmission of the terminal device based on that location. In some examples, the processor 301 can configure the uplink transmission to facilitate the arrival of uplink communication signals from the terminal device at the network access node at an appropriate time, where the communication interface 303 is configured to receive uplink transmissions. This configuration may include adjusting parameters such as timing advance to compensate for propagation delays caused by the distance between the terminal device and the network access node.

[0102] Processor 301 can encode a random access response message for transmission to a terminal device in response to a received physical random access channel transmission. The random access response message may include configurations related to timing adjustments (e.g., timing advance values) based on the terminal device's location. Processor 301 can also analyze demodulated reference signals received from the terminal device via uplink transmissions, according to the various aspects described herein. Processor 301 can monitor changes associated with uplink communication signals received from the terminal device (such as changes in Doppler offset or round-trip time delay) and can continue to track how the terminal device's location evolves over time.

[0103] Figure 8An example block diagram is shown that uses a received physical random access channel (PRAM) signal, including a PRAM preamble encoded by the terminal device, to determine the round-trip time delay and Doppler offset of the terminal device via hypothesis testing. For each of a plurality of hypotheses regarding Doppler offset, processor 301 may execute blocks 801, 802, 803, and 804 as described herein. As described herein, processor 301 may determine the round-trip time delay and Doppler offset of the terminal device via hypothesis testing. In 801, processor 301 may obtain frequency symbols received within the PRAM resources. Processor 301 may linearly offset the received frequency domain symbols by a corresponding amount for each Doppler offset hypothesis, wherein the corresponding offset for each Doppler offset hypothesis is an integer of the PRAM subcarrier spacing. The number of Doppler offset hypotheses and the corresponding offsets can be specified based on the use case.

[0104] In block 802, processor 301 can remove the hypothesized physical random access channel (PRAM) preamble sequence from the corresponding offset frequency domain symbols of the respective Doppler offset hypotheses. The hypothesized PRAM preamble may be a predetermined PRAM preamble for a corresponding PRAM resource. In some examples, processor 301 may perform block 802 on multiple hypothesized PRAM preambles that the terminal device is capable of transmitting. Processor 301 can estimate the frequency domain channel by multiplying the offset frequency domain symbols by the conjugate of the transmitted sequence symbols of the hypothesized PRAM preamble at each subcarrier.

[0105] Multiplication allows processor 801 to consider hypothetical physical random access channel preambles to be transmitted by the terminal device and estimate the fit of each Doppler offset hypothesis with the received physical random access channel signal. Accordingly, processor 301 can determine which Doppler offset hypothesis best matches the actual conditions experienced by the terminal device.

[0106] In 803, processor 301 can obtain the time-domain channel by performing an inverse fast Fourier transform (IFFT) operation on the estimated frequency-domain channel. In 804, processor 301 can verify the peak value of the time-domain channel by comparing the amplitude of the time-domain channel with a threshold. When the peak value is verified, the physical random access channel preamble can be detected. Processor 301 can use the orientation of the peak value to derive timing advance. Furthermore, the processor can determine the actual Doppler offset as either the Doppler offset hypothesis that generates the highest effective peak value or a linear combination of Doppler offset hypotheses that generate effective peak values.

[0107] Illustratively, when a terminal device transmits a Physical Random Access Channel (PRAN) preamble while moving relative to a network access node, this motion will result in round-trip time delay and Doppler shift affecting the received signal. In 801, processor 301 can apply various Doppler shift assumptions to account for different possible speeds of the terminal device. In 802, processor 301 can then remove the PRAN preamble sequence for each assumption from these shifted signals and estimate a frequency-domain channel for each assumption. By comparing these estimated channels, in 804, processor 301 is able to verify which assumption best matches reality, thus allowing processor 301 to accurately estimate both the round-trip time delay and timing advance, as well as the Doppler shift (used for speed estimation).

[0108] Based on the aspects described herein, processor 301 can identify received physical random access channel (PRAM) transmissions and decode them to identify the PRAM signal at the PRAM resource. In some examples, processor 301 can perform hypothesis testing on the PRAM preamble received from the terminal device using multiple Doppler offset hypotheses. Each Doppler offset hypothesis can be correlated with a corresponding offset in the frequency of the received symbol of the PRAM signal at the PRAM resource.

[0109] For each Doppler offset hypothesis, processor 301 can estimate the respective frequency domain channel for that Doppler offset hypothesis by analyzing how the received frequency symbols are affected by different Doppler offsets. By comparing the estimated frequency domain channels, processor 301 can select the Doppler offset hypothesis that best matches the actual conditions experienced by the terminal device. For example, when the terminal device transmits a physical random access channel preamble, the signal may experience different levels of Doppler offset depending on the relative velocity between the terminal device and the network access node. Processor 301 can generate multiple hypotheses, each corresponding to a different Doppler offset value.

[0110] For each hypothesis, processor 301 can estimate how the received frequency symbols will appear in the frequency domain under a specific Doppler offset. Processor 301 can then compare these estimated channels for different Doppler offset hypotheses to determine which hypothesis provides the best match. Accordingly, processor 301 can select one of the Doppler offset hypotheses based on the respective frequency domain channel estimates for each Doppler offset hypothesis. Once the most accurate Doppler offset hypothesis is selected, processor 301 can refine its estimates of other key parameters, such as round-trip time delay and timing advance, to ensure that future uplink transmissions from the terminal device are synchronized with other devices in the coverage area.

[0111] In some examples, processor 301 can, for instance, obtain the corresponding time-domain signal by using an inverse fast Fourier transform, converting the corresponding frequency-domain channel into a corresponding time-domain channel. Once in the time domain, processor 301 can analyze the time-domain signal to identify peaks in the time-domain channel. The location of these peaks in the time domain can correspond to the timing of the received physical random access channel signal, and processor 301 can use the timing of the received physical random access channel signal to determine the round-trip time delay.

[0112] For example, as shown in 803 of the first figure, after applying the Doppler offset assumption and removing the assumed physical random access channel preamble sequence, processor 301 can perform an inverse fast Fourier transform operation on the estimated frequency domain channel. This can result in a time domain channel where peaks represent strong signal reflections or direct paths between the terminal device and the network access node. In 804, processor 301 can identify these peaks by comparing their amplitudes to predetermined thresholds. Once a peak is verified, processor 301 can use the orientation of the peak in the time domain channel to derive the round-trip time delay. Illustratively, processor 301 can determine the round-trip time delay by measuring the distance the peak is offset in time from the expected reference point. For example, if the peak occurs later than expected, processor 301 determines that the longer propagation delay exists due to the increased distance between the terminal device and the network access node. By determining the round-trip time delay, processor 301 can adjust timing parameters such as timing advance based on the round-trip time delay to synchronize future uplink transmissions from the terminal device.

[0113] Processor 301 can determine the Doppler offset by selecting the Doppler offset hypothesis that produces the largest peak in the time-domain channel. In some examples, processor 301 can select the Doppler offset hypothesis that results in the highest verified peak (i.e., the peak with the largest amplitude) as the actual Doppler offset experienced by the terminal device. By selecting the hypothesis with the highest peak, processor 301 can use that peak for further processing, such as orientation determination or timing advance adjustment. In some examples, processor 301 can compute a linear combination of Doppler offset hypotheses that produce peaks above a certain threshold. This approach can become useful when multiple hypotheses produce valid peaks in the time-domain channel, indicating that more than one Doppler offset hypothesis can contribute to the observed signal characteristics. Processor 301 can compare the amplitude of the identified peaks among the Doppler offset hypotheses with a predetermined threshold. If multiple Doppler offset hypotheses produce peaks above the threshold, rather than selecting only one hypothesis, processor 301 can compute a weighted linear combination of these hypotheses. In some examples, the weights can be proportional to the amplitude of each peak.

[0114] Processor 301 can configure uplink transmissions of the terminal device. In some examples, processor 301 can configure an uplink frequency on which the terminal device transmits a designated frequency band allocated for uplink communication. Additionally, processor 301 can configure the transmit power of the terminal device to ensure that the uplink signal is strong enough to be reliably received by the network access node while minimizing interference with other devices. In some examples, the uplink transmission configuration may include scheduling the terminal device as described herein based on a time-division duplex communication mode of the network access node. Furthermore, processor 301 can determine the modulation and coding scheme (MCS) for uplink transmissions based on factors such as channel quality and service requirements.

[0115] Based on the aspects described herein, processor 301 can obtain round-trip time delay and timing advance. Processor 301 can further configure uplink transmissions based on the round-trip time delay and timing advance. For example, once both the round-trip time delay and Doppler offset are estimated, processor 301 can configure uplink transmissions for the terminal device by adjusting the timing advance, which ensures that future uplink transmissions from the terminal device arrive at the network access node at precisely synchronized intervals. As described herein, uplink configuration may include sending a random access response message. In addition to configuring the initial uplink transmission, processor 301 can continue to track changes in the terminal device's orientation and velocity over time by analyzing demodulation reference signals embedded in subsequent uplink transmissions. In some examples, processor 301 can configure and schedule how and when the terminal device will provide these demodulation reference signals.

[0116] A network access node can perform various operations to manage communication with terminal devices by acquiring and processing demodulation reference signals transmitted by the terminal devices. The demodulation reference signal is crucial for channel estimation, allowing the processor 301 to accurately demodulate uplink signals and track the location and movement of the terminal devices. The network access node can receive the demodulation reference signal embedded in the uplink transmission from the terminal device, and the processor 301 can decode the signal received from the terminal device to obtain the terminal device's demodulation reference signal. The processor 301 can process the demodulation reference signal to estimate uplink channel conditions, such as signal strength, phase, and timing. By analyzing the demodulation reference signal, the processor 301 can correct any distortion caused by noise, interference, or Doppler shift due to the movement of the terminal device.

[0117] In dynamic environments such as non-terrestrial networks, terminal devices can experience significant Doppler shifts due to their relative motion to network access nodes. Processor 301 can use a demodulated reference signal to estimate these Doppler shifts by comparing received frequency-domain symbols with known reference symbols. This estimation allows processor 301 to adjust timing and frequency parameters as described herein. By processing the demodulated reference signal, processor 301 can continue to track changes in channel conditions, enabling it to dynamically adjust resource allocation for uplink transmissions. In some examples, processor 301 can use this information to refine its estimation of round-trip time delay.

[0118] In some aspects, processor 301 can estimate time offset and / or frequency offset based on a demodulated reference signal received from the terminal device. Processor 301 can receive the demodulated reference signal from the terminal device. Once received, processor 301 can analyze the demodulated reference signal to estimate both time offset and frequency offset. Illustratively, processor 301 can perform channel estimation based on the received demodulated reference signal. For example, processor 301 can multiply the received demodulated reference signal symbols by the conjugate of the transmitted demodulated reference symbol sequence to estimate the frequency domain channel. This operation allows processor 301 to determine how the signal is affected by the transmission medium. Once the frequency domain channel is estimated, processor 301 can estimate the time offset by performing a conjugate multiplication between channels on two different subcarriers within the same orthogonal frequency division multiplexing symbol. This operation can help identify any timing misalignment between the terminal device and the network access node, which may be caused by propagation delay or movement of the terminal device. Furthermore, the processor 301 can perform conjugate multiplication across two different orthogonal frequency division multiplexing symbols on the same subcarrier. Conjugate multiplication allows the processor 301 to detect any frequency shifts that may have occurred due to the Doppler effect, which is common in scenarios where there is relative motion between the terminal device and the satellite-based network access node.

[0119] By analyzing both the time and frequency offsets from these operations, processor 301 can track changes in signal timing and frequency caused by the movement of the terminal device. In some examples, processor 301 can use this information to adjust uplink transmission parameters, such as timing advance or frequency correction. In summary, starting from the moment the terminal device receives the demodulation reference signal, processor 301 can perform channel estimation using the demodulation reference signal symbols, estimate the time offset by comparing different subcarriers within an orthogonal frequency division multiplexing (OFDM) symbol, and estimate the frequency offset by comparing subcarriers across different OFDM symbols.

[0120] Therefore, the time offset can be considered as indicating how much adjustment is needed to synchronize uplink transmissions from the terminal device with other devices in the coverage area. Furthermore, the frequency offset can indicate how much correction is needed to align the uplink transmissions with the expected frequency. Once both the time and frequency offsets are estimated, the processor 301 can compare these values ​​with previous estimates to determine any changes over time, which can provide insight into how fast and in what direction the terminal device is moving relative to the network access node. By continuing to detect these changes, the processor 301 can update its previous estimates of the terminal device's location.

[0121] In some examples, processor 301 can estimate the frequency offset based on a received demodulation reference signal by performing a conjugate multiplication between channel estimates across the same subcarriers of two different orthogonal frequency division multiplexing (OFDM) symbols. Processor 301 can receive these demodulation reference signals and estimate channel conditions when the terminal device transmits them as part of its uplink transmission. To estimate the frequency offset, processor 301 can compare how the channel changes between two consecutive OFDM symbols on the same subcarrier, which can be achieved by performing a conjugate multiplication between channel estimates derived from each OFDM symbol. Processor 301 can determine the extent of the frequency offset based on the result of this multiplication; the offset can typically be caused by the Doppler effect due to relative motion between the terminal device and the network access node.

[0122] In some examples, processor 301 can estimate the time offset based on the respective received demodulation reference signals by performing conjugate multiplication between channels on two different subcarriers within the same orthogonal frequency division multiplexing (OFDM) symbol. This operation allows processor 301 to detect any timing misalignments between the terminal device and the network access node that may arise due to propagation delays or movement of the terminal device. By comparing how the different subcarriers behave differently within a single OFDM symbol, processor 301 can determine whether any time offsets need to be corrected. For example, after estimating the frequency offset as described herein, processor 301 can also perform conjugate multiplication between different subcarriers within the OFDM symbol to estimate the time offset as described herein.

[0123] In the context of tracking the orientation of a terminal device, processor 301 operates by continuously monitoring and analyzing various signal characteristics, such as round-trip time delay, Doppler shift, and demodulation reference signal. Orientation tracking corresponds to processor 301 not only determining the initial position of the terminal device but also updating that position over time as the terminal device and / or network access node move relative to each other. Processor 301 achieves tracking by comparing changes in signal timing, frequency shift, and other propagation metrics between consecutive transmissions from the terminal device. By analyzing these changes, processor 301 can estimate how far and in what direction the terminal device has moved relative to the network access node.

[0124] For example, processor 301 can determine at least one further orientation of the terminal device to track its movement over time, which differs from the initial orientation determined based on the physical random access channel preamble. After determining the initial orientation of the terminal device using methods such as analyzing the physical random access channel preamble and estimating round-trip time delay and Doppler offset, processor 301 can continue to monitor and update the orientation of the terminal device. This may involve continuing to receive and process signals from the terminal device, such as demodulation reference signals embedded in uplink transmissions. By analyzing changes in signal characteristics over time (such as changes in Doppler offset or timing offset), processor 301 is able to estimate how the location of the terminal device has evolved.

[0125] Once the processor 301 has determined at least one further orientation of the terminal device, it can calculate the signal Doppler offset and sampling offset related to signal transmission between the network access node and the terminal device. The processor 301 can calculate the Doppler offset by analyzing frequency variations observed in consecutive uplink transmissions from the terminal device. In some examples, the processor 301 can perform hypothesis testing to account for different possible Doppler offsets and select or combine hypotheses that produce a valid peak. Accordingly, the processor 301 can estimate the Doppler offset value.

[0126] Processor 301 can also determine sampling offset. The processor can determine the sampling offset by analyzing how much the signal timing changes between consecutive transmissions, which can be caused by clock inaccuracies at the network access node or terminal device, or by distance changes due to the movement of the terminal device. By comparing timing information across multiple signals (e.g., demodulation reference signal or physical random access channel preamble), processor 301 can estimate how much offset has occurred and thus adjust the uplink transmission parameters.

[0127] In some examples, processor 301 can determine the last acquired orientation of the terminal device as at least one further orientation. Processor 301 can derive this last acquired orientation from the previously tracked location using methods such as analyzing the physical random access channel preamble, demodulating the reference signal, and calculating the round-trip time delay and Doppler offset. Once the orientation is determined, processor 301 can use the last acquired orientation to encode or decode the communication signal based on the calculated signal Doppler offset and sampling offset. For example, when the terminal device transmits an uplink signal, processor 301 can analyze the Doppler offset to adjust for frequency variations caused by the relative motion between the terminal device and the network access node. Simultaneously, processor 301 can consider the sampling offset, which can be caused by clock inaccuracies or changes in distance between the terminal device and the network access node. By compensating for both the Doppler offset and the sampling offset, processor 301 can ensure that the communication signal is accurately encoded or decoded, thereby maintaining synchronization and preventing interference.

[0128] In some examples, after determining the Doppler offset and sampling offset, processor 301 can instruct the digital front-end (DFE) of the network access node, which may include communication interface 303, to perform frequency conversion and data resampling based on these calculated values. The digital front-end can be configured to convert received analog signals to digital form and vice versa. By adjusting the frequency conversion process according to the Doppler offset, processor 301 can configure the signal to be correctly aligned in frequency before the signal is further processed. Similarly, by instructing the digital front-end to resample data based on the calculated sampling offset, processor 301 can correct timing discrepancies caused by clock inaccuracies or movement of end devices.

[0129] In some examples, processor 301 can perform inverse operations on both signal Doppler offset and sampling offset to mitigate the effects of Doppler offset and sampling offset on the communication signal. Specifically, this inverse operation can be designed to counteract two key issues: inter-carrier interference (ICI) within a single orthogonal frequency division multiplexing (OFDM) symbol and phase shifts across multiple OFDM symbols. ICI occurs when frequency shifts caused by the Doppler effect lead to overlap between adjacent subcarriers within an OFDM symbol, thus degrading signal quality. By applying the inverse Doppler offset operation, processor 301 can realign these subcarriers to reduce ICI and improve signal clarity. Additionally, phase shifts across multiple OFDM symbols can occur due to time shifts caused by sampling offsets. By applying the inverse operation to account for this offset, processor 301 can maintain phase continuity across consecutive symbols to reduce demodulation errors and improve overall communication reliability.

[0130] Figure 9An example block diagram based on the aspects described herein is shown, illustrating the process for estimating and suppressing Doppler offset and sampling offset for tracking the orientation of a terminal device with respect to a network access node. Processor 301 can perform the operations described in this block diagram.

[0131] It should be noted that the block diagrams described herein are examples used to illustrate various aspects of the operation of processor 301 with respect to terminal devices and network access nodes. Those skilled in the art will recognize that these diagrams are presented on an exemplary basis and that certain blocks or steps may be omitted, combined, or modified depending on a particular implementation or system requirements. For example, some blocks may represent intermediate processing steps that can be performed in a different order or may not be necessary in all configurations. Additionally, the functionality of multiple blocks may be integrated into a single block or distributed across multiple components without departing from the scope. The diagrams are intended to provide a high level of understanding of the processes involved and should not be construed as limiting the scope of the claims.

[0132] In 901, processor 301 can estimate Doppler offset and timing advance via a physical random access channel. Processor 301 can illustratively receive a physical random access channel preamble from the terminal device and perform hypothesis testing to estimate the Doppler offset, which can account for the relative motion between the terminal and the network access node. Timing advance can be derived from the round-trip time delay, which represents the signal propagation time between the terminal device and the network access node.

[0133] Once these initial parameters have been estimated, in step 902, processor 301 can perform initial user equipment location acquisition. Processor 301 can use Doppler offset and round-trip time delay to estimate the initial orientation of the terminal equipment within the coverage area. Processor 301 can calculate this initial location by analyzing how far the terminal is located relative to the network access node and in what direction it is located.

[0134] In 903, after acquiring the initial position, processor 301 can configure uplink transmissions for the terminal device. Processor 301 can receive demodulated reference signals from these configured uplink transmissions from the terminal device and estimate both frequency and time offsets. Frequency offsets are caused by the Doppler effect due to relative motion, while time offsets are caused by propagation delays or clock inaccuracies. These offsets are crucial for refining the initial position estimation and dynamically adjusting uplink transmission parameters to maintain synchronization between the terminal device and the network access node.

[0135] Next, in block 904, processor 301 can perform initial user equipment location tracking, which may include tracking the orientation of the user equipment. Processor 301 can continue to monitor changes in frequency and time offset over time to track how the orientation of the terminal equipment evolves. By comparing these new measurements with previous estimates, processor 301 can update its estimate of the terminal equipment's location as the terminal equipment and / or network access nodes move relative to each other.

[0136] The second stage of processing can begin at 910, where processor 301 can perform Doppler offset and sampling offset estimation. Processor 301 can perform this estimation based on the output of initial user equipment location acquisition (i.e., 902) and / or initial user equipment location tracking (i.e., 904), which may involve calculating both Doppler offset and sampling offset based on the signal characteristics received from the demodulated reference signal. Note that sampling offset can refer to changes in signal timing caused by clock inaccuracies or variations in distance between the terminal and the network access node. By estimating these parameters, processor 301 can correct any timing or frequency differences that may affect uplink transmission.

[0137] In 920, processor 301 can apply Doppler shift and sampling shift suppression. This block can correct for both Doppler-induced frequency shift and sampling shift, thereby ensuring that future uplink transmissions remain synchronized with other devices in the coverage area. Processor 301 can apply Doppler shift and sampling shift suppression using known methods to fully utilize the previously determined or tracked azimuth of the terminal device. Processor 301 can apply Doppler shift and sampling shift suppression. This can involve compensating for both Doppler-induced frequency shift and sampling shift to maintain accurate communication between the terminal device and the network access node. The suppression process corrects these effects by adjusting frequency conversion parameters and resampled data in real time, thereby ensuring that uplink transmissions are correctly aligned with other devices in the coverage area. By continuously updating its estimates of Doppler shift and sampling shift based on real-time data from the demodulated reference signal, and by tracking changes in azimuth using the physical random access channel preamble, processor 301 can determine that communication remains synchronized even when the terminal device moves within or across the coverage area.

[0138] Figure 10An example of the method is shown. Method 1000 may include: determining a round-trip time delay for transmissions to a network access node 1001; determining a time-division duplex communication mode, which may include a plurality of time slots for communication between the network access node and a terminal device, wherein the plurality of time slots includes a first time slot and a second time slot 1002; allocating a first time slot among the plurality of time slots to the network access node to perform uplink communication and / or downlink communication with the terminal device 1003; scheduling the terminal device to transmit an uplink signal to the network access node or receive a downlink signal from the network access node during at least one of the plurality of second time slots 1004.

[0139] Figure 11 An example of the method is shown. Method 1100 may include: determining the orientation of the terminal device 1101 based on a Physical Random Access Channel (PRACH) preamble received from the terminal device; configuring uplink transmission of the terminal device 1102; and tracking the orientation of the terminal device 1103 based on a demodulation reference signal received from the terminal device. A non-transitory computer-readable medium may include instructions that, when executed by a processor, cause the processor to perform method 1100.

[0140] The following examples cover further aspects.

[0141] In Example 1, the subject includes an apparatus that may include a processor configured to: determine a round-trip time delay for transmissions to a network access node; determine a time-division duplex communication mode that may include a plurality of time slots for communication between the network access node and a terminal device, wherein the plurality of time slots includes a first time slot and a second time slot; allocate a first time slot among the plurality of time slots to the network access node to perform uplink communication and / or downlink communication with the terminal device; and schedule the terminal device to transmit an uplink signal to the network access node or receive a downlink signal from the network access node during at least one of the plurality of second time slots.

[0142] In Example 2, the subject of Example 1 may also include: the processor may also be configured to: allocate a second time slot among a plurality of time slots, during which the network access node is scheduled to idle to communicate with the terminal device.

[0143] In Example 3, the subject of Example 2 may also include: the second time slot includes several time slots based on round-trip time delay.

[0144] In Example 4, the subject of any of Examples 1 to 3 is that the processor is further configured to schedule the terminal device to operate idle during at least one of the plurality of first time slots to communicate with the network access node.

[0145] In Example 5, the subject of Example 4 is that at least one of the first time slots is based on round-trip time delay.

[0146] In Example 6, the subject of any of Examples 1 through 5 is used, where the round-trip time delay is determined based on the location of the terminal device.

[0147] In Example 7, the subject of Example 6 is followed, wherein the processor is configured to: instruct a network access node to provide network access services to multiple terminal devices, which may include terminal devices within a coverage area, wherein the round-trip time delay is a common round-trip time delay determined for the multiple terminal devices within the coverage area.

[0148] In Example 8, the subject of Example 7 is that the common round-trip time delay is the minimum round-trip time delay among the round-trip time delays determined for multiple terminal devices within the coverage area.

[0149] In Example 9, the subject of Example 7 or Example 8 is further configured to: determine a further round-trip time delay for each of a plurality of terminal devices in the coverage area, wherein the combination of the common round-trip time delay and the respective further round-trip time delay indicates the corresponding total round-trip time delay of the respective terminal device.

[0150] In Example 10, the subject of Example 9 is further configured to estimate the respective round-trip time delay of the terminal devices based on their orientation.

[0151] In Example 11, the subject of Example 9 or Example 10, wherein the processor is further configured to: estimate each further round-trip time delay based on the physical random access channel transmission received from the terminal device; and encode a random access message for transmission of a random access response in response to the received physical random access channel transmission, wherein the timing advance value of the random access response is based on the round-trip time delay.

[0152] In Example 12, the subject of any of Examples 1 to 11, wherein the processor is further configured to calculate the number of second time slots by dividing the round-trip time delay into the slot duration of the time-division duplex communication mode.

[0153] In Example 13, the subject of any of Examples 1 to 12, wherein the first time slot comprises one or more consecutive uplink time slots and one or more consecutive downlink time slots, wherein the second time slot is provided between one or more consecutive uplink time slots and one or more consecutive downlink time slots.

[0154] In Example 14, the subject of any of Examples 1 through 13, wherein the network access node belongs to a non-terrestrial network, wherein the network access node is a satellite access node or a satellite-based network access node.

[0155] In Example 15, the subject matter includes an apparatus for a network access node, which may include a processor configured to: determine the location of a terminal device based on a physical random access channel preamble received from a terminal device; configure uplink transmission of the terminal device; and track the location of the terminal device based on a demodulation reference signal received from the terminal device.

[0156] In Example 16, the subject of Example 15 is further configured to: estimate the round-trip time delay and Doppler offset associated with the preamble of the physical random access channel; and determine the orientation of the terminal device by analyzing the round-trip time delay and Doppler offset.

[0157] In Example 17, the subject of Example 15 or Example 16, the processor is further configured to: perform hypothesis testing on a physical random access channel preamble using multiple Doppler offset hypotheses, each Doppler offset hypothesis being associated with a respective offset of a frequency symbol received at a physical random access channel resource; estimate a respective frequency domain channel for the respective offset of the received frequency symbol; and select one of the multiple Doppler offset hypotheses based on the respective frequency domain channel for each Doppler offset hypothesis.

[0158] In Example 18, the subject of Example 17 is further configured to: convert the respective frequency domain channels into corresponding time domain channels; identify peaks in the corresponding time domain channels; and determine round-trip time delays based on the orientation of the peaks.

[0159] In Example 19, the subject of Example 18 is further configured to identify peaks by comparing the magnitude with a peak threshold.

[0160] In Example 20, the subject of Example 18 or Example 19, the processor is further configured to determine the Doppler offset by selecting the one with the highest peak among a plurality of Doppler offset hypotheses.

[0161] In Example 21, the subject of Example 18 or Example 19, the processor is further configured to determine the Doppler offset by calculating a linear combination of Doppler offset assumptions that produce respective peaks above a peak threshold.

[0162] In Example 22, the subject of any of Examples 15 to 21 is provided, wherein the processor is further configured to: estimate the time offset and frequency offset based on the received demodulated reference signal; determine the changes in the estimated time offset and frequency offset; and update the orientation of the terminal device based on the changes.

[0163] In Example 23, the subject of Example 22 is further configured to estimate the respective frequency offsets based on the respective received demodulation reference signals by performing conjugate multiplication between channel estimates of the same subcarriers across two different orthogonal frequency division multiplexing symbols.

[0164] In Example 24, the subject of Example 23 is further configured to estimate the respective time offsets based on the respective received demodulation reference signals by performing conjugate multiplication between channels on two different subcarriers within the same orthogonal frequency division multiplexing symbol.

[0165] In Example 25, the subject of any of Examples 15 to 24, wherein the processor is further configured to: determine at least one further orientation of the terminal device for tracking the orientation of the terminal device.

[0166] In Example 26, the subject of Example 25 is further configured to: calculate the signal Doppler offset and sampling offset related to signal transmission between the network access node and the terminal device based on at least one further orientation of the terminal device.

[0167] In Example 27, the subject of Example 25 or Example 26, wherein at least one further orientation is the last orientation obtained by the terminal device, wherein the processor is further configured to communicate with the terminal device by encoding or decoding the communication signal based on the calculated signal Doppler offset and sampling offset.

[0168] In Example 28, the subject of any of Examples 26 to 27, wherein the processor is further configured to: instruct the digital front end of the network access node to perform frequency conversion and data resampling based on the calculated signal Doppler offset and sampling offset.

[0169] In Example 29, the subject of any of Examples 26 to 28, wherein the processor is further configured to: perform the inverse operation of signal Doppler shift and sampling frequency shift to induce inter-carrier interference within a single orthogonal frequency division multiplexing symbol and to induce phase changes of the communication signal across multiple orthogonal frequency division multiplexing symbols.

[0170] In Example 30, the subject of any of Examples 15 to 29 is a network access node belonging to a non-terrestrial network, wherein the network access node is a satellite access node or a satellite-based network access node.

[0171] In Example 31, the subject of Example 30 is that the location of the terminal device is determined based on the location of the network access node and / or satellite within a non-terrestrial network.

[0172] In Example 32, the subject includes a method that may include: determining a round-trip time delay for transmissions to a network access node; determining a time-division duplex communication mode, the time-division duplex communication mode including multiple time slots for communication between the network access node and a terminal device, wherein the multiple time slots include first time slots and second time slots; allocating a first time slot among the multiple time slots to the network access node to perform uplink communication and / or downlink communication with the terminal device; and scheduling the terminal device to transmit uplink signals to the network access node or receive downlink signals from the network access node during at least one of the multiple second time slots.

[0173] In Example 33, the subject of Example 32 may also include: allocating a second time slot among multiple time slots, during which the network access node is scheduled for idle operation to communicate with the terminal device.

[0174] In Example 34, the subject of Example 33 may also include: the second time slot includes several time slots based on round-trip time delay.

[0175] In Example 35, the subject of any of Examples 32 to 34 may further include: scheduling a terminal device to operate idle during at least one of a plurality of first time slots to communicate with a network access node.

[0176] In Example 36, the subject matter of Example 35 may also include: scheduling the terminal device to neither perform uplink communication with the network access node nor downlink communication with the network access node during at least one of the plurality of first time slots.

[0177] In Example 37, the subject of Example 36 is that at least one of the time slots in a first time slot is based on round-trip time delay.

[0178] In Example 38, the subject of any of Examples 32 to 37 is that the round-trip time delay is determined based on the location of the terminal device.

[0179] In Example 39, the subject of Example 38 may also include: instructing a network access node to provide network access services to multiple terminal devices, which may include terminal devices within a coverage area, wherein the round-trip time delay is a common round-trip time delay determined for the multiple terminal devices within the coverage area.

[0180] In Example 40, the subject of Example 39, the common round-trip time delay is the minimum round-trip time delay among the round-trip time delays determined for multiple terminal devices within the coverage area.

[0181] In Example 41, the subject matter of Example 39 or Example 40 may also include: determining a further round-trip time delay for each of a plurality of terminal devices within the coverage area, wherein the combination of the common round-trip time delay and the respective further round-trip time delay indicates the corresponding total round-trip time delay for the respective terminal device.

[0182] In Example 42, the subject of Example 41 may also include: estimating the respective round-trip time delay of each terminal device based on the location of the terminal device.

[0183] In Example 43, the subject matter of Example 41 or Example 42 may further include: estimating each further round-trip time delay based on the physical random access channel transmission received from the terminal device; and encoding a random access message for transmission of a random access response in response to the received physical random access channel transmission, wherein the timing advance value of the random access response is based on the round-trip time delay.

[0184] In Example 44, the subject of any of Examples 32 to 43, wherein the first time slot comprises one or more consecutive uplink time slots and one or more consecutive downlink time slots, wherein the second time slot is provided between one or more consecutive uplink time slots and one or more consecutive downlink time slots.

[0185] In Example 45, the subject of any of Examples 32 to 44 is a network access node belonging to a non-terrestrial network, wherein the network access node is a satellite access node or a satellite-based network access node.

[0186] In Example 46, the subject includes a method for a network access node, which may include: determining the location of a terminal device based on a physical random access channel preamble received from the terminal device; configuring uplink transmission of the terminal device; and tracking the location of the terminal device based on a demodulation reference signal received from the terminal device.

[0187] In Example 47, the subject matter of Example 46 may also include: estimating the round-trip time delay and Doppler offset associated with the preamble of the physical random access channel; and determining the orientation of the terminal device by analyzing the round-trip time delay and Doppler offset.

[0188] In Example 48, the subject matter of Example 46 or Example 47 may also include: performing hypothesis testing on a physical random access channel preamble using multiple Doppler offset hypotheses, each Doppler offset hypothesis being associated with a respective offset of a frequency symbol received at a physical random access channel resource; estimating a respective frequency domain channel for the respective offset of the received frequency symbol; and for each Doppler offset hypothesis, selecting one of the multiple Doppler offset hypotheses based on the respective frequency domain channel.

[0189] In Example 49, the subject matter of Example 48 may also include: converting the respective frequency domain channels into corresponding time domain channels; identifying peaks in the corresponding time domain channels; and determining round-trip time delay based on the orientation of the peaks.

[0190] In Example 50, the subject of Example 49 may also include: identifying peaks by comparing the magnitude with a peak threshold.

[0191] In Example 51, the subject of Example 49 or Example 50 may also include: determining the Doppler offset by selecting the one with the highest peak among a plurality of Doppler offset hypotheses.

[0192] In Example 52, the subject of Example 49 or Example 50 may also include determining the Doppler offset by calculating a linear combination of Doppler offset assumptions that produce respective peaks above the peak threshold.

[0193] In Example 53, the subject matter of any of Examples 46 to 52 may further include: estimating the time offset and frequency offset based on the received demodulated reference signal; determining the changes in the estimated time offset and frequency offset; and updating the orientation of the terminal device based on the changes.

[0194] In Example 54, the subject matter of Example 53 may also include: estimating the respective frequency offsets based on the respective received demodulation reference signals by performing conjugate multiplication between channel estimates of the same subcarriers across two different orthogonal frequency division multiplexing symbols.

[0195] In Example 55, the subject matter of Example 54 may also include: estimating the respective time offsets based on the respective received demodulation reference signals by performing conjugate multiplication between channels on two different subcarriers within the same orthogonal frequency division multiplexing symbol.

[0196] In Example 56, the subject matter of any one of Examples 46 to 55 may further include: determining at least one further orientation of the terminal device for tracking the orientation of the terminal device.

[0197] In Example 57, the subject matter of Example 46 may also include: calculating the signal Doppler offset and sampling offset related to signal transmission between the network access node and the terminal device based on at least one further orientation of the terminal device.

[0198] In Example 58, the subject of Example 56 or Example 57, wherein at least one further orientation is the last orientation obtained by the terminal device, wherein the method may further include: communicating with the terminal device by encoding or decoding the communication signal based on the calculated signal Doppler offset and sampling offset.

[0199] In Example 59, the subject matter of any of Examples 57 to 58 may also include: instructing the digital front end of a network access node to perform frequency conversion and data resampling based on calculated signal Doppler offset and sampling offset.

[0200] In Example 60, the subject matter of any of Examples 57 to 59 may also include: performing the inverse operation of signal Doppler offset and sampling offset to induce inter-carrier interference within a single orthogonal frequency division multiplexing symbol and to induce phase changes of the communication signal across multiple orthogonal frequency division multiplexing symbols.

[0201] In Example 61, the subject of any of Examples 46 to 60 is a network access node belonging to a non-terrestrial network, wherein the network access node is a satellite access node or a satellite-based network access node.

[0202] In Example 62, the subject of Example 61 is that the orientation of the terminal device is determined based on the orientation of the network access node and / or satellite within a non-terrestrial network.

[0203] In Example 63, the subject matter is a non-transitory computer-readable medium including instructions that, when executed by a processor, cause the processor to perform any of the methods in Examples 32 to 62.

[0204] The terms “multiple” and “multiple” in the description and claims clearly refer to a quantity greater than one. The terms “group of,” “set of,” “collection of,” “series of,” “sequence of,” “group of,” etc., in the description and claims refer to a quantity equal to or greater than one, i.e., one or more. Any term expressed in plural form that does not explicitly state “multiple” or “multiple” also refers to a quantity equal to or greater than one.

[0205] Any vector and / or matrix symbols used herein are exemplary in nature and are for illustrative purposes only. Therefore, the apparatuses and methods described herein with accompanying vector and / or matrix symbols are not limited to implementation using only vectors and / or matrices, and the related processes and computations can be performed equivalently with respect to sets, sequences, groups, etc., of data, observations, information, signals, samples, symbols, elements, etc.

[0206] As used herein, “memory” is understood to be a non-transitory computer-readable medium capable of storing data or information for retrieval. Therefore, references to “memory” as included herein can be understood to refer to volatile or non-volatile memory, including random access memory (“RAM”), read-only memory (“ROM”), flash memory, solid-state memory, magnetic tape, hard disk drive, optical disk drive, etc., or any combination thereof. Furthermore, registers, shift registers, processor registers, data buffers, etc., are also included herein with the term memory. A single component referred to as “memory” or “memory memory” may consist of more than one different type of memory, and therefore may refer to a collection of components including one or more types of memory. Any single memory component may be divided into multiple common equivalent memory components, and vice versa. Furthermore, while memory may be depicted as separate from one or more other components (as in the figures), memory may also be integrated with other components, such as on a common integrated chip or on a controller with embedded memory.

[0207] The term "software" refers to any type of executable instructions, including firmware.

[0208] In the context described herein, the term "process" may be used, for example, to indicate a method. Illustratively, any process described herein can be implemented as a method (e.g., a channel estimation process can be understood as a channel estimation method). Any process described herein can be implemented as a non-transitory computer-readable medium comprising instructions configured, upon execution, to cause one or more processors to perform the process (e.g., to perform the method).

[0209] Throughout the accompanying drawings, it should be noted that, unless otherwise stated, similar reference numerals are used to depict the same or similar elements, features, and structures. It should also be noted that, for simplicity, certain components may be omitted.

[0210] The phrases “at least one” and “one or more” can be understood to include a numerical quantity greater than or equal to one (e.g., one, two, three, four, [...] etc.). The phrase “at least one of…” relating to a group of elements can be used herein to mean at least one element from a group of elements. For example, the phrase “at least one of…” relating to a group of elements can be used herein to mean a selection: one of the listed elements, one of a plurality of listed elements, a plurality of individual listed elements, or a plurality of multiples of individual listed elements.

[0211] The terms “plural” and “multiple” in the description and claims clearly refer to a quantity greater than one. Therefore, any phrase explicitly invoking the preceding terms referring to a quantity of elements (e.g., “plural [elements]”, “multiple [elements]”) clearly refers to more than one of the elements. For example, the phrase “multiple” can be understood to include a numerical quantity greater than or equal to two (e.g., two, three, four, five, [...] etc.).

[0212] As used herein, a signal or information that "indicates," "represents," "represents," or "indicates" a value or other information can be a digital or analog signal that encodes or otherwise transmits the value or other information in a manner that enables the receiving component to decode and / or cause a response action in the receiving component. Before the receiving component receives the signal, the signal can be stored or buffered in a computer-readable storage medium, and the receiving component can retrieve the signal from the storage medium. Furthermore, a "value" that "indicates" or "represents" some quantity, state, or parameter can be physically embodied as a digital signal, an analog signal, or storage bits that encode or otherwise transmit the value.

[0213] As used herein, signals can be transmitted or conducted through a signal chain, where the signal is processed to change characteristics such as phase, amplitude, and frequency. Even after these characteristics are adapted, the signals can still be referred to as the same signal. Generally, a signal can be considered the same signal as long as it continues to encode the same information. For example, a transmitted signal can be considered to refer to transmitted signals at baseband frequencies, intermediate frequencies, and radio frequencies.

[0214] For example, the terms "processor" or "controller" as used herein can be understood as any kind of technical entity that allows the processing of data. Data can be processed according to one or more specific functions performed by the processor. Furthermore, a processor or controller as used herein can be understood as any kind of circuit, such as any kind of analog or digital circuit. Therefore, a processor or controller can be or includes analog circuits, digital circuits, mixed-signal circuits, logic circuits, processors, microprocessors, central processing units, graphics processing units, digital signal processors, field-programmable gate arrays, integrated circuits, application-specific integrated circuits, etc., or any combination thereof. Any other kind of implementation of the various functions described in further detail below can also be understood as a processor, controller, or logic circuit. It should be understood that any two (or more) of the processors, controllers, or logic circuits detailed herein can be implemented as a single entity with equivalent functionality, and conversely, any single processor, controller, or logic circuit detailed herein can be implemented as two (or more) separate entities with equivalent functionality.

[0215] The term "one or more processors" is intended to refer to a processor or controller. One or more processors may include a single processor or multiple microprocessors. These terms are used only as alternative expressions for "processor" or "controller".

[0216] The term "user device" is intended to refer to a device that can be configured to provide information relevant to a user (e.g., a user). Exemplary user devices may include mobile phones, smartphones, wearable devices (e.g., smartwatches, smart wristbands), computers, and the like.

[0217] As used herein, the terms “module,” “component,” “system,” “circuit,” “element,” “slice,” “line,” etc., are intended to refer to a collection of one or more electronic components, computer-related entities, hardware, software (e.g., in execution), and / or firmware. For example, a circuit or similar term can be a processor, a process running on a processor, a controller, an object, an executable program, a storage device, and / or a computer having processing capabilities. By way of illustration, an application running on a server and a server can also be a circuit. One or more lines can exist within the same circuit, and a circuit can be located on one computer and / or distributed among two or more computers. A collection of elements or other circuits can be described herein, wherein the term “collection” can be interpreted as “one or more.”

[0218] As used herein, the term "data" can be understood to include information in any suitable analog or digital form, such as being provided as a file, a portion of a file, a collection of files, a signal or stream, a portion of a signal or stream, a collection of signals or streams, etc. Furthermore, the term "data" can also be used to mean a reference to information, for example, in the form of a pointer. However, the term "data" is not limited to the foregoing examples and can take various forms and represent any information as understood in the art. The term "data item" can include data or a portion of data.

[0219] It will be understood that when a component is referred to as being "connected" or "coupled" to another component, that component is physically connected or coupled to the other component, allowing current and / or electromagnetic radiation (e.g., signals) to flow along the conductive path formed by that component. Essentially, such a component can be connected or coupled to another component. When components are described as being coupled or connected to each other, an intervening conductive, inductive, or capacitive component can exist between one component and the other. Furthermore, when coupled or connected to each other, one component can induce voltage or current flow or electromagnetic wave propagation in the other component without physical contact or an intervening component. Additionally, when voltage, current, or signal is referred to as being "provided" to a component, the voltage, current, or signal can be conducted to the component either through a physical connection or through capacitive, electromagnetic, or inductive coupling that does not involve a physical connection.

[0220] Unless explicitly stated otherwise, the term "instance of time" refers to the time of a specific event or situation, depending on the context. An instance of time can refer to a point in time or a period of time involving a specific event or situation.

[0221] Unless explicitly stated otherwise, the term “transmit” includes both direct (point-to-point) transmission and indirect transmission (via one or more intermediate points). Similarly, the term “receive” includes both direct reception and indirect reception. Furthermore, the terms “transmit,” “receive,” “communication,” and other similar terms include both physical transmission (e.g., transmission of wireless signals) and logical transmission (e.g., transmission of digital data via a logical software-level connection). For example, a processor or controller can transmit or receive data in the form of wireless signals via a software-level connection to another processor or controller, wherein physical transmission and reception are handled by wireless layer components such as radio frequency (RF) transceivers and antennas, and logical transmission and reception via a software-level connection are performed by the processor or controller. The term “communication” includes one or both of transmission and reception, i.e., one-way or two-way communication in one or both of the inbound and outbound directions. The term “computation” includes both “direct” computation via mathematical expressions / formulas / relationships and “indirect” computation via lookup tables or hash tables and other array indexing or search operations.

[0222] While the above descriptions and connection diagrams depict electronic device components as individual elements, those skilled in the art will understand the various possibilities of combining or integrating discrete components into a single element. This can include: combining two or more circuits to form a single circuit; mounting two or more circuits onto a common chip or chassis to form an integrated element; executing discrete software components on a common processor core, etc. Conversely, those skilled in the art will recognize the possibility of separating a single element into two or more discrete elements, such as splitting a single circuit into two or more separate circuits, separating a chip or chassis into discrete elements initially provided thereon, separating software components into two or more segments and executing each segment on a separate processor core, etc.

[0223] It should be understood that the implementation of the methods detailed herein is demonstrative in nature and is therefore to be understood as being capable of being implemented in the corresponding device. Similarly, it should be understood that the implementation of the devices detailed herein is to be understood as being capable of being implemented as the corresponding methods. Therefore, it should be understood that the device corresponding to the methods detailed herein may include one or more components configured to perform each aspect of the relevant methods. All abbreviations defined in the above description additionally apply to all claims contained herein.

Claims

1. An apparatus comprising: Memory; and a processor, the processor being configured to: Determine the round-trip time delay for transmissions used at network access nodes; A time-division duplex communication mode is determined, wherein the time-division duplex communication mode includes multiple time slots for communication between the network access node and the terminal device, wherein the multiple time slots include a first time slot and a second time slot; Assigning the first time slot from the plurality of time slots to the network access node to perform uplink and / or downlink communication with the terminal device; and The terminal device is scheduled to transmit uplink signals to or receive downlink signals from the network access node during at least one of the plurality of second time slots.

2. The apparatus according to claim 1, wherein The processor is also configured to allocate the second time slot among the plurality of time slots, during which the network access node is scheduled to idle for communication with the terminal device.

3. The apparatus according to claim 2, wherein The second time slot includes a plurality of time slots based on the round-trip time delay.

4. The apparatus according to claim 1, wherein The processor is also configured to schedule the terminal device to operate idle during at least one of the plurality of first time slots to communicate with the network access node.

5. The apparatus according to claim 4, wherein Several time slots in the at least one first time slot are based on the round-trip time delay.

6. The apparatus according to any one of claims 1 to 5, wherein The round-trip time delay is determined based on the location of the terminal device. The processor is configured to: instruct the network access node to provide network access services to multiple terminal devices, the multiple terminal devices including those within the coverage area, and The round-trip time delay is a common round-trip time delay determined for the plurality of terminal devices within the coverage area.

7. The apparatus according to claim 6, wherein The processor is also configured to determine the orientation of the terminal device based on the Doppler offset determined for the terminal device.

8. The apparatus according to any one of claims 1 to 5, wherein, The first time slot includes one or more consecutive uplink time slots and one or more consecutive downlink time slots, and The second time slot is provided between the one or more consecutive uplink time slots and the one or more consecutive downlink time slots.

9. The apparatus according to any one of claims 1 to 5, wherein, The network access node belongs to a non-terrestrial network, and The network access node is a satellite access node or a satellite-based network access node.

10. An apparatus comprising: Memory; and a processor, the processor being configured to: The location of the terminal device is determined based on the physical random access channel preamble received from the terminal device. Configure the uplink transmission of the terminal device; and The orientation of the terminal device is tracked based on the demodulation reference signal received from the terminal device.

11. The apparatus according to claim 10, wherein, The processor is also configured to: Estimate the round-trip time delay and Doppler offset associated with the preamble of the physical random access channel; as well as The orientation of the terminal device is determined by analyzing the round-trip time delay and the Doppler offset.

12. The apparatus according to claim 11, wherein The processor is also configured to: The physical random access channel preamble is subjected to hypothesis testing using multiple Doppler offset hypotheses, each of which is associated with a respective offset of a frequency symbol received at the physical random access channel resource. Estimate the respective frequency domain channels for the respective offsets of the received frequency symbols; as well as One of the plurality of Doppler shift hypotheses is selected based on the respective frequency domain channel for each Doppler shift hypothesis.

13. The apparatus according to claim 12, wherein The processor is also configured to: Convert the respective frequency domain channels into corresponding time domain channels; Identify the peak values ​​in the corresponding time-domain channel; and The round-trip time delay is determined based on the location of the peak value.

14. The apparatus according to claim 13, wherein The processor is also configured to identify the peak value by comparing the magnitude with a peak threshold.

15. The apparatus according to any one of claims 10 to 14, wherein The processor is also configured to: Based on the received demodulated reference signal, estimate the time offset and frequency offset; Determine the estimated changes in the time offset and the frequency offset; as well as Based on the changes, the orientation of the terminal device is updated.

16. The apparatus according to claim 15, wherein, The processor is also configured to estimate the respective frequency offsets based on the respective received demodulation reference signals by performing conjugate multiplication between channel estimates of the same subcarriers across two different orthogonal frequency division multiplexing symbols.

17. The apparatus according to claim 16, wherein The processor is also configured to estimate the respective time offset based on the respective received demodulation reference signals by performing conjugate multiplication between channels on two different subcarriers within the same orthogonal frequency division multiplexing symbol.

18. The apparatus according to any one of claims 10 to 14, wherein The processor is further configured to: determine at least one further orientation of the terminal device, for tracking the orientation of the terminal device, and The processor is further configured to: calculate the signal Doppler offset and sampling offset related to signal transmission between the network access node and the terminal device based on the at least one further orientation of the terminal device.

19. A non-transitory computer-readable medium comprising instructions that, when executed by a processor, cause the processor to: The location of the terminal device is determined based on the physical random access channel preamble received from the terminal device. Configure the uplink transmission of the terminal device; and The orientation of the terminal device is tracked based on the demodulation reference signal received from the terminal device.

20. The non-transitory computer-readable medium of claim 19, wherein, The instructions also cause the processor to: Estimate the round-trip time delay and Doppler offset associated with the preamble of the physical random access channel; as well as The orientation of the terminal device is determined by analyzing the round-trip time delay and the Doppler offset.

Images