Feeder links for transparent NTN nodes

Abstract

A method includes: receiving a signal including a feeder link time slot having a feeder link bandwidth on a feeder link; mapping each feeder link time slot in the feeder link time slot to a corresponding time slot subband in a corresponding service link time slot according to a rule; sending a service signal on multiple service links, each of the service signals including one or more corresponding service link time slots in the service link time slot, each service link time slot including m time slot subbands with the same bandwidth in the time slot subband; the m time slot subbands do not overlap, are continuous with each other, and cover the entire service link bandwidth of the corresponding service link time slot; the feeder link time slot has a feeder link time slot duration; the service link time slot has a service link time slot duration longer than the feeder link time slot duration; each feeder link time slot in the feeder link time slot includes a corresponding symbol; each time slot subband in the time slot subband includes a symbol of the feeder link time slot mapped to the corresponding time slot subband.

Description

Technical Field

[0001] The present disclosure relates to non-terrestrial networks, in particular to feeder links in NTNs.

[0002] Abbreviations

[0003] 2T2R: 2 transmit 2 receive (channel)

[0004] 3GPP: Third Generation Partnership Project

[0005] 5G / 6G / 7G: 5th / 6th / 7th generation

[0006] AAS: Active Antenna System

[0007] ADC: Analog-to-Digital Converter

[0008] BBU: Baseband Unit

[0009] CP: Cyclic Prefix

[0010] DAC: Digital to Analog Converter

[0011] DFT: Discrete Fourier Transform

[0012] DFTS-OFDM: DFT spread OFDM DL: Downlink direction (from gNB to UE)

[0013] eNB: eNodeB (LTE base station)

[0014] FDD: Frequency Division Duplex

[0015] FFT: Fast Fourier Transform

[0016] FL: Feeder Link; link between HAPS / satellite and ground station

[0017] FR1: Frequency Range 1 (spectrum below 6 GHz in NR)

[0018] FR2: Frequency Range 2 (24.25-52.6GHz in NR)

[0019] gNB: gNodeB (NR base station)

[0020] HAPS: High Altitude Platform Station

[0021] HARQ: Hybrid Automatic Repeat Request

[0022] HPA: High Power Amplifier

[0023] HW: Hardware

[0024] IFFT: Inverse Fast Fourier Transform

[0025] IQ: In-Phase and Quadrature

[0026] LEO: Low Earth Orbit

[0027] LNA: Low Noise Amplifier

[0028] LTE: Long Term Evolution

[0029] MAC: Media Access Control

[0030] NR: New Radio

[0031] NTN: Non-Terrestrial Network

[0032] OFDM: Orthogonal Frequency Division Multiplexing

[0033] PHY: Physical layer

[0034] P to S: Parallel to Serial Converter

[0035] RACH: Random Access Channel

[0036] RNA: Radio Access Network

[0037] RB: Resource Block

[0038] RF: Radio Frequency

[0039] RIC: Radio Intelligent Controller

[0040] RSF: Resampling function

[0041] SCS: Subcarrier Spacing

[0042] SL: Service Link; the communication link between the end user (UE) and HAPS (satellite)

[0043] S to P: Serial to Parallel Converter

[0044] TDD: Time Division Duplex

[0045] TDM: Time Division Multiplexing

[0046] TN: Terrestrial Network

[0047] TR: Technical Report

[0048] TS: Technical Specification

[0049] UE: User Equipment

[0050] UL: Uplink direction (from UE to gNB) Background Art

[0051] HAPS (High Altitude Platform Station)[1] is a communication node deployed in the stratosphere at an altitude of 18-24 km to provide wide coverage on the ground. The aerial platform of HAPS can be a balloon[2] or an unmanned aircraft[3][4]. Recent technological advances in aviation, solar energy and battery efficiency have enabled HAPS to remain afloat and operate continuously for months.

[0052] 3GPP[5][6] has explored the use of HAPS and satellites to provide data services to 5G New Radio (NR) user devices. Non-terrestrial networks (NTNs) including HAPS or satellites can provide services to large areas that are currently inaccessible to terrestrial networks, serving the maritime and air transport industries, and providing critical communications for public safety and disaster relief. 3GPP is currently developing specifications for the NR standard for NTN in Release 17. In this application, the terms "satellite" and "HAPS" are used interchangeably unless otherwise specified.

[0053] Figure 1 The deployment scenario of NTN is shown. The "service link" between HAPS / satellite 11 and UE 13 can use 4G LTE or 5G NR air interface to deliver data services to UE. The "feeder link" between HAPS / satellite and ground gateway station 12 transmits aggregated user data to and from the core network. Typically, NTN is implemented in a regenerative or bent pipe (also known as transparent) architecture.

[0054] In the regenerative architecture, 4G / 5G base station functions are partially or fully implemented on the HAPS / satellite, and at least part of the PHY / MAC processing (such as packet encoding, decoding, and / or scheduling) is performed on the HAPS and the satellite. However, in the bent pipe architecture, the full base station (eNB or gNB) is located in the gateway station, and the HAPS or satellite only acts as a repeater or relay between the UE and the ground station. In this case, the HAPS / satellite only performs frequency conversion and power amplification between the service link and the feeder link.

[0055] NR supports multiple different types of subcarrier spacing (in LTE, there is only one type of subcarrier spacing, 15kHz). The types of NR numerology (specifying the frame structure, which includes subframes, SCS, cyclic prefix and time slots) are specified in 3GPP TS 38.211 [7]. The SCS of different NR numerologies is indicated in Table 1 (Table 4.2-1 of 3GPP TS38.211).

[0056]

[0057]

[0058] Table 1: Numerical basic configuration specified for NR (adapted from Table 4.2-1 of 3GPP TS 38.211)

[0059] As shown in Table 1, each digital basic configuration is marked with a parameter μ. The digital basic configuration (μ = 0) indicates SCS = 15kHz, which is the same as LTE. The subcarrier spacing of other μ is derived from (μ = 0) by scaling it up by a power of 2. The cyclic prefix acts as a buffer area or guard interval (in the time domain) to protect the OFDM signal from inter-symbol interference. The smaller the SCS, the longer the cyclic prefix (guard interval).

[0060] Downlink, uplink and sidelink transmissions are organized into frames of 10ms duration, each frame consisting of 10 subframes of 1ms duration. As shown in Table 2, for a standard cyclic prefix, the number of consecutive OFDM symbols in a time slot depends on the cyclic prefix, (for an extended cyclic prefix, the number of consecutive OFDM symbols in a time slot is smaller):

[0061]

[0062] Table 2: Number of OFDM symbols per slot (column 2), number of slots per frame (column 3), and number of slots per subframe (column 4) for the standard cyclic prefix specified for each digital basic configuration (column 1) for NR (Table 4.3.2-1 of 3GPP TS 38.211)

[0063] A resource block (RB) is the smallest unit of resources that can be allocated to a user. In NR, a resource block is 14 symbols (1 slot) in the time domain and 12 subcarriers in the frequency domain.

[0064] References

[0065] [1]https: / / www.itu.int / en / mediacentre / backgrounders / Pages / High-altitude-platform-systems.aspx.

[0066] [2]Loon homepage.https: / / loon.com / .

[0067] [3]HAPS MOBILE.https: / / www.hapsmobile.com / en / .

[0068] [4]Airbus Zephyr.https: / / www.airbus.com / defence / uav / zephyr.html.

[0069] [5]3GPP TR 38.811, “Study on New Radio(NR) to support non terrestrialnetworks.”

[0070] [6]3GPP TR 38.821, “Solutions for NR to support non-terrestrialnetworks(NTN).”

[0071] [7]3GPP TS 38.211, "NR Physical channels and modulation" Summary of the invention

[0072] The object of the present invention is to improve the prior art.

[0073] According to a first aspect of the present invention, there is provided a device, the device comprising:

[0074] One or more processors and a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform:

[0075] receiving a downlink feeder signal on a feeder link, the downlink feeder signal comprising a feeder link downlink time slot in the time domain, the feeder link downlink time slot having a feeder link bandwidth in the frequency domain, the feeder link bandwidth having a feeder link subcarrier spacing;

[0076] Mapping each feeder link downlink time slot in the feeder link downlink time slot to a corresponding time slot subband in the corresponding service link downlink time slot according to a rule;

[0077] On each of the plurality of service links, a corresponding downlink service signal is sent, wherein

[0078] Each of the downlink service signals comprises, in the time domain: a respective one or more of the service link downlink time slots;

[0079] Each of the serving link downlink time slots comprises, in the frequency domain: m time slot subbands in the time slot subband, where m is a positive integer;

[0080] In each of the serving link downlink time slots, the m time slot subbands are arranged in the frequency domain to have the same bandwidth and have a serving link subcarrier spacing;

[0081] In each of the serving link downlink time slots, in the frequency domain, the m time slot subbands do not overlap, are continuous with each other, and cover the entire serving link bandwidth of the corresponding serving link downlink time slot; wherein

[0082] The feeder link downlink time slot has a feeder link time slot duration;

[0083] The serving link downlink time slot has a serving link time slot duration that is longer than the feeder link time slot duration;

[0084] The feeder link subcarrier spacing is larger than the serving link subcarrier spacing;

[0085] Each of the feeder link time slots comprises a corresponding symbol;

[0086] Each of the slot subbands includes symbols of a feeder link downlink time slot mapped to the corresponding slot subband.

[0087] When the instruction is executed by the one or more processors, the device may execute:

[0088] Receiving a corresponding uplink service signal on each service link of a plurality of service links; including a corresponding service link uplink time slot in the time domain, the corresponding service link uplink time slot having a service link bandwidth in the frequency domain, the service link bandwidth comprising: corresponding m time slot subbands in the time slot subbands arranged at the service link subcarrier interval;

[0089] According to the rule, mapping each of the m time slot subbands in each of the serving link uplink time slots to the corresponding feeder link uplink time slot;

[0090] According to the rule, feeder link uplink time slots are arranged in the time domain with feeder link subcarrier spacing in the frequency domain to obtain an uplink feeder signal;

[0091] An uplink feeder signal is transmitted on the feeder link, where

[0092] Each of the uplink service signals comprises, in the time domain: a respective one or more of the serving link uplink time slots;

[0093] The feeder link uplink time slot has a feeder link time slot duration;

[0094] The serving link uplink timeslot has a serving link timeslot duration;

[0095] Each of the serving link uplink time slots comprises a corresponding symbol;

[0096] Each of the feeder link uplink time slots includes symbols of a time slot subband mapped to a serving link uplink time slot on the corresponding feeder link time slot.

[0097] When the instruction is executed by the one or more processors, the apparatus may further cause the apparatus to perform mapping of each time slot sub-band in each of the service link uplink time slots to the corresponding feeder link uplink time slot in the following manner:

[0098] down-converting a service link uplink time slot of a corresponding time slot sub-band to a baseband uplink service signal;

[0099] sampling a baseband uplink service signal at a service link subcarrier spacing to obtain digital uplink samples corresponding to a corresponding time slot subband;

[0100] The digital uplink samples are upconverted and compressed in time to obtain the corresponding feeder link uplink time slots.

[0101] The feeder link may have a higher carrier frequency than the serving link.

[0102] When the instruction is executed by the one or more processors, the apparatus may further perform mapping of each feeder link downlink time slot in the feeder link downlink time slot to a corresponding time slot subband in the corresponding service link downlink time slot in the following manner:

[0103] down-converting the feeder link downlink time slot to a baseband downlink feeder signal;

[0104] sampling a baseband downlink feeder signal at a feeder link subcarrier spacing to obtain digital downlink samples corresponding to a corresponding feeder link downlink time slot;

[0105] For each service link in service-links:

[0106] determining a corresponding digital downlink sample in the digital downlink samples according to the rule;

[0107] Up-converting and spreading the determined digital downlink samples in time to obtain corresponding time slot subbands;

[0108] According to the rule, the time slot subbands belonging to the corresponding service link downlink time slot are combined to obtain the corresponding service link downlink time slot.

[0109] When the instruction is executed by the one or more processors, it can cause the device to perform a mapping of each feeder link downlink time slot in the feeder link downlink time slot to the corresponding service link downlink time slot, so that on each service link in the service link, the numbering of the corresponding service link downlink time slot is continuous, and the corresponding service link downlink time slots are continuous in time on the corresponding service link.

[0110] When the instruction is executed by the one or more processors, the device may execute:

[0111] Information is received on a control link regarding at least one of a feeder slot duration, a service slot duration, a feeder link subcarrier spacing, a service link subcarrier spacing, and a rule for mapping feeder link downlink slots onto slot subbands of a service link downlink slot.

[0112] At least one of the feeder slot duration, the serving slot duration, the feeder link subcarrier spacing, the serving link subcarrier spacing, and a rule for mapping the feeder link downlink slots onto the slot subbands of the serving link downlink slots may be predefined.

[0113] When the instruction is executed by the one or more processors, the device may execute:

[0114] detecting whether one of the feeder link downlink time slots is empty;

[0115] If one of the feeder link downlink time slots is empty:

[0116] reducing the transmit power of a serving link downlink timeslot, one of the feeder link downlink timeslots being mapped on the serving link downlink timeslot; and

[0117] The power of one or more of the serving link downlink time slots is boosted, wherein one of the feeder link downlink time slots is not mapped on any of the one or more of the serving link downlink time slots.

[0118] The detecting may include detecting whether information notifying that one of the feeder link downlink time slots is empty is received.

[0119] According to a second aspect of the present invention, there is provided a device, the device comprising:

[0120] One or more processors and a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform:

[0121] providing each of the plurality of cells with a respective downlink signal to be transmitted in a respective one or more feeder link downlink time slots on a feeder link to the satellite;

[0122] According to a rule, feeder link time slots of a plurality of cells are arranged in a staggered manner to obtain feeder link downlink signals to be transmitted on the feeder links.

[0123] The rule may indicate that: for each cell in the plurality of cells, a corresponding number m of feeder link downlink time slots corresponds to m time slot subbands in a corresponding service link downlink time slot of the corresponding cell, m being a positive integer; and the instruction, when executed by the one or more processors, may cause the apparatus to perform, for each cell in the cells:

[0124] Arranging the feeder link downlink time slots so that the m feeder link downlink time slots corresponding to the m subbands in the corresponding serving link downlink time slot of the corresponding cell are subsequent in the feeder link downlink time slot of the corresponding cell;

[0125] For each pair of time slot subbands of a first service link downlink time slot in a service link downlink time slot of a corresponding cell and a time slot subband of a second service link downlink time slot in a service link downlink time slot of the corresponding cell: if the rule indicates that on a service link between the satellite and the corresponding cell, the first service link downlink time slot in a service link downlink time slot of the corresponding cell is earlier in time than the second service link downlink time slot in the service link downlink time slot of the corresponding cell, then in the feeder link downlink signal, the feeder link downlink time slot corresponding to the time slot subband of the first service link downlink time slot in the service link downlink time slot of the corresponding cell is arranged to be earlier in time than the feeder link downlink time slot corresponding to the time slot subband of the second service link downlink time slot in the service link downlink time slot of the corresponding cell.

[0126] For at least one cell among the plurality of cells, one of the following may be applicable to the rule:

[0127] The rule indicates that: for each of the serving link downlink time slots of the corresponding cell, for each pair of a first time slot subband of the corresponding serving link downlink time slot and a second time slot subband of the corresponding serving link downlink time slot, if the first time slot subband has a higher subband index than the second time slot subband, in the feeder link downlink signal, the feeder link downlink time slot corresponding to the first time slot subband is arranged to be earlier in time than the feeder link downlink time slot corresponding to the second time slot subband;

[0128] Or the rule indicates: for each service link downlink time slot in the service link downlink time slots of the corresponding cell, for each pair of time slot subbands of the third time slot subband of the corresponding service link downlink time slot and the fourth time slot subband of the corresponding service link downlink time slot, if the third time slot subband has a higher subband index than the fourth time slot subband, then in the feeder link downlink signal, the feeder link downlink time slot corresponding to the fourth time slot subband is arranged to be earlier in time than the feeder link downlink time slot corresponding to the third time slot subband.

[0129] According to a third aspect of the present invention, there is provided a device, the device comprising:

[0130] One or more processors and a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform:

[0131] monitoring whether a bandwidth of a feeder link is sufficient to transmit a corresponding downlink signal to each of the plurality of cells via the feeder link, and keeping at least one feeder link time slot on the feeder link empty, wherein for each of the cells, the corresponding downlink signal is transmitted on the feeder link in the corresponding one or more feeder link downlink time slots;

[0132] If the bandwidth of the feeder link is sufficient, sending of the downlink signal is scheduled such that at least one of the feeder link downlink time slots is empty.

[0133] When the instruction is executed by the one or more processors, the device may also execute:

[0134] A controller is notified of at least one empty feeder link downlink time slot.

[0135] According to a fourth aspect of the present invention, there is provided a device, the device comprising:

[0136] One or more processors and a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform:

[0137] Indicates at least one of a feeder slot duration on a feeder link slot, a service slot duration on a service link slot, a feeder link subcarrier spacing, a service link subcarrier spacing, and a rule for mapping a feeder link slot to a service link slot.

[0138] When the instruction is executed by the one or more processors, the device may execute:

[0139] The base station is informed of at least one of a feeder link time slot duration and a feeder link subcarrier spacing, wherein the feeder link time slot belongs to a feeder link signal to be transmitted on a feeder link between the base station and the satellite.

[0140] According to a fifth aspect of the present invention, there is provided a device, the device comprising:

[0141] One or more processors and a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform:

[0142] monitoring whether information that at least one feeder link downlink time slot among a plurality of feeder link downlink time slots on the feeder link is empty is received;

[0143] If information that one of the feeder link downlink time slots is empty is received, the satellite is informed that one of the feeder link downlink time slots is empty.

[0144] According to a sixth aspect of the present invention, there is provided a method, the method comprising:

[0145] receiving a downlink feeder signal on a feeder link, the downlink feeder signal comprising a feeder link downlink time slot in the time domain, the feeder link downlink time slot having a feeder link bandwidth in the frequency domain, the feeder link bandwidth having a feeder link subcarrier spacing;

[0146] Mapping each feeder link downlink time slot in the feeder link downlink time slot to a corresponding time slot subband in the corresponding service link downlink time slot according to a rule;

[0147] On each of the plurality of service links, a corresponding downlink service signal is sent, wherein

[0148] Each of the downlink service signals comprises, in the time domain: a respective one or more of the service link downlink time slots;

[0149] Each of the serving link downlink time slots comprises, in the frequency domain: m time slot subbands in the time slot subband, where m is a positive integer;

[0150] In each of the serving link downlink time slots, the m time slot subbands are arranged in the frequency domain to have the same bandwidth and have a serving link subcarrier spacing;

[0151] In each of the serving link downlink time slots, in the frequency domain, the m time slot subbands do not overlap, are continuous with each other, and cover the entire serving link bandwidth of the corresponding serving link downlink time slot; wherein

[0152] The feeder link downlink time slot has a feeder link time slot duration;

[0153] The serving link downlink time slot has a serving link time slot duration that is longer than the feeder link time slot duration;

[0154] The feeder link subcarrier spacing is larger than the serving link subcarrier spacing;

[0155] Each of the feeder link time slots comprises a corresponding symbol;

[0156] Each of the slot subbands includes symbols of a feeder link downlink time slot mapped to the corresponding slot subband.

[0157] The method may further include:

[0158] receiving a corresponding uplink service signal on each of a plurality of service links; in the time domain, comprising a corresponding service link uplink time slot, the corresponding service link uplink time slot having a service link bandwidth in the frequency domain, the service link bandwidth comprising corresponding m time slot subbands of time slot subbands arranged at a service link subcarrier spacing;

[0159] Mapping each of the m time slot subbands in each of the serving link uplink time slots to a corresponding feeder link uplink time slot according to the rule;

[0160] According to the rule, feeder link uplink time slots are arranged in the time domain with feeder link subcarrier spacing in the frequency domain to obtain an uplink feeder signal;

[0161] An uplink feeder signal is transmitted on the feeder link, where

[0162] Each of the uplink service signals comprises in the time domain a respective one or more of the serving link uplink time slots;

[0163] The feeder link uplink time slot has a feeder link time slot duration;

[0164] The serving link uplink timeslot has a serving link timeslot duration;

[0165] Each of the serving link uplink time slots comprises a corresponding symbol;

[0166] Each of the feeder link uplink time slots includes symbols of a time slot subband mapped to a serving link uplink time slot on a corresponding feeder link time slot.

[0167] The mapping of each time slot sub-band in each of the serving link uplink time slots onto the corresponding feeder link uplink time slot may include:

[0168] down-converting a service link uplink time slot of a corresponding time slot sub-band to a baseband uplink service signal;

[0169] sampling a baseband uplink service signal at a service link subcarrier spacing to obtain digital uplink samples corresponding to a corresponding time slot subband;

[0170] The digital uplink samples are upconverted and compressed in time to obtain the corresponding feeder link uplink time slots.

[0171] The feeder link may have a higher carrier frequency than the serving link.

[0172] The method may also include mapping each of the feeder link downlink time slots to a corresponding time slot subband in the corresponding service link downlink time slot by:

[0173] down-converting the feeder link downlink time slot to a baseband downlink feeder signal;

[0174] sampling a baseband downlink feeder signal at a feeder link subcarrier spacing to obtain digital downlink samples corresponding to a corresponding feeder link downlink time slot;

[0175] For each service link in service-links:

[0176] determining, according to the rule, corresponding ones of the digital downlink samples;

[0177] Up-converting and spreading the determined digital downlink samples in time to obtain corresponding time slot subbands;

[0178] According to the rule, the time slot subbands belonging to the corresponding service link downlink time slot are combined to obtain the corresponding service link downlink time slot.

[0179] Mapping of each feeder link downlink time slot in the feeder link downlink time slots to the corresponding service link downlink time slots can be performed so that on each service link in the service links, the numbering of the corresponding service link downlink time slots is continuous and the corresponding service link downlink time slots are continuous in time on the corresponding service link.

[0180] The method may further include:

[0181] Information is received on a control link regarding at least one of a feeder slot duration, a service slot duration, a feeder link subcarrier spacing, a service link subcarrier spacing, and a rule for mapping feeder link downlink slots onto slot subbands of a service link downlink slot.

[0182] At least one of the feeder slot duration, the serving slot duration, the feeder link subcarrier spacing, the serving link subcarrier spacing, and a rule for mapping the feeder link downlink slots onto the slot subbands of the serving link downlink slots may be predefined.

[0183] The method may further include:

[0184] detecting whether one of the feeder link downlink time slots is empty;

[0185] If one of the feeder link downlink time slots is empty:

[0186] reducing the transmit power of a serving link downlink timeslot, one of the feeder link downlink timeslots being mapped on the serving link downlink timeslot; and

[0187] The power of one or more of the serving link downlink time slots is boosted, wherein one of the feeder link downlink time slots is not mapped on any of the one or more of the serving link downlink time slots.

[0188] The detecting may include detecting whether information notifying that one of the feeder link downlink time slots is empty is received.

[0189] According to a seventh aspect of the present invention, there is provided a method, the method comprising:

[0190] providing each of the plurality of cells with a respective downlink signal to be transmitted in a respective one or more feeder link downlink time slots on a feeder link to the satellite;

[0191] According to a rule, feeder link time slots of a plurality of cells are arranged in a staggered manner to obtain feeder link downlink signals to be transmitted on the feeder links.

[0192] The rule may indicate that: for each cell in the plurality of cells, a respective number m of feeder link downlink time slots corresponds to m time slot subbands in a respective serving link downlink time slot of the respective cell, m being a positive integer; and the method may further include performing, for each cell in the cells:

[0193] Arranging the feeder link downlink time slots so that the m feeder link downlink time slots corresponding to the m subbands in the corresponding serving link downlink time slot of the corresponding cell are subsequent in the feeder link downlink time slot of the corresponding cell;

[0194] For each pair of time slot subbands of a first service link downlink time slot in a service link downlink time slot of a corresponding cell and a second service link downlink time slot in a service link downlink time slot of the corresponding cell: if the rule indicates that on a service link between the satellite and the corresponding cell, the first service link downlink time slot in a service link downlink time slot of the corresponding cell is earlier in time than the second service link downlink time slot in the service link downlink time slot of the corresponding cell, then in the feeder link downlink signal, the feeder link downlink time slot corresponding to the time slot subband of the first service link downlink time slot in the service link downlink time slot of the corresponding cell is arranged to be earlier in time than the feeder link downlink time slot corresponding to the time slot subband of the second service link downlink time slot in the service link downlink time slot of the corresponding cell.

[0195] For at least one cell among the plurality of cells, one of the following may be applicable to the rule:

[0196] The rule indicates that: for each of the serving link downlink time slots of the corresponding cell, for each pair of a first time slot subband of the corresponding serving link downlink time slot and a second time slot subband of the corresponding serving link downlink time slot, if the first time slot subband has a higher subband index than the second time slot subband, in the feeder link downlink signal, the feeder link downlink time slot corresponding to the first time slot subband is arranged to be earlier in time than the feeder link downlink time slot corresponding to the second time slot subband;

[0197] Or the rule indicates: for each service link downlink time slot in the service link downlink time slots of the corresponding cell, for each pair of time slot subbands of the third time slot subband of the corresponding service link downlink time slot and the fourth time slot subband of the corresponding service link downlink time slot, if the third time slot subband has a higher subband index than the fourth time slot subband, then in the feeder link downlink signal, the feeder link downlink time slot corresponding to the fourth time slot subband is arranged to be earlier in time than the feeder link downlink time slot corresponding to the third time slot subband.

[0198] According to an eighth aspect of the present invention, there is provided a method, the method comprising:

[0199] monitoring whether a bandwidth of a feeder link is sufficient to transmit a corresponding downlink signal to each of the plurality of cells via the feeder link, and keeping at least one feeder link time slot on the feeder link empty, wherein for each of the cells, the corresponding downlink signal is transmitted on the feeder link in the corresponding one or more feeder link downlink time slots;

[0200] If the bandwidth of the feeder link is sufficient, sending of the downlink signal is scheduled such that at least one of the feeder link downlink time slots is empty.

[0201] The method may further include:

[0202] A controller is notified of at least one empty feeder link downlink time slot.

[0203] According to a ninth aspect of the present invention, there is provided a method, the method comprising:

[0204] Indicates at least one of a feeder slot duration on a feeder link slot, a service slot duration on a service link slot, a feeder link subcarrier spacing, a service link subcarrier spacing, and a rule for mapping a feeder link slot to a service link slot.

[0205] The method may further include:

[0206] The base station is informed of at least one of a feeder link time slot duration and a feeder link subcarrier spacing, wherein the feeder link time slot belongs to a feeder link signal to be transmitted on a feeder link between the base station and the satellite.

[0207] According to a tenth aspect of the present invention, there is provided a method, the method comprising:

[0208] monitoring whether information that at least one feeder link downlink time slot among a plurality of feeder link downlink time slots on the feeder link is empty is received;

[0209] If information that one of the feeder link downlink time slots is empty is received, the satellite is informed that one of the feeder link downlink time slots is empty.

[0210] Each of the methods of the sixth to tenth aspects of the present invention may be a satellite communication method.

[0211] According to an eleventh aspect of the present invention, there is provided a computer program product comprising an instruction set, which, when executed on a device, is configured to cause the device to perform a method according to any one of aspects 6 to 10. The computer program product may be embodied as a computer readable medium, or may be directly loadable into a computer.

[0212] According to some embodiments of the present invention, at least one of the following advantages can be achieved:

[0213] Transparent satellite / HAPS can support multiple cells even with high throughput;

[0214] Communications on the feeder link become more robust (preventing phase noise);

[0215] The service link can have a wide coverage area;

[0216] No hardware modification is required;

[0217] Leverage existing NR standards;

[0218] UE is not affected;

[0219] • Enhanced power saving and / or power boosting methods may be used on SL.

[0220] It should be understood that any of the above modifications may be applied alone or in combination to the corresponding aspects to which they refer, unless they are explicitly indicated as excluding alternatives. BRIEF DESCRIPTION OF THE DRAWINGS

[0221] Further details, features, objects and advantages will be apparent from the following detailed description of preferred embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0222] Figure 1 Shows how HAPS or satellite can use multiple beams for service link coverage;

[0223] Figure 2 The spectrum usage on the service link and the feeder link is shown;

[0224] Figure 3A block diagram showing a HAPS / satellite payload with one 2T2R serving link cell with 15kHz SCS and a feeder link with 30kHz SCS according to some example embodiments of the present invention;

[0225] Figure 4 An example of two cells in a serving link according to some example embodiments of the present invention is shown;

[0226] Figure 5 shows an FL view and an SL view of a time slot of a dual-cell system according to some example embodiments of the present invention;

[0227] Figure 6 shows feeder link transmission using 100 MHz bandwidth and 120 kHz SCS according to some example embodiments of the present invention;

[0228] Figure 7 shows feeder link transmission using 100 MHz bandwidth and 120 kHz SCS to support 4 service links using both TDM and FDM mapping of time slots according to some example embodiments of the present invention;

[0229] Figure 8 An example is shown where the bandwidth on the feeder link is insufficient to support all cells in the serving link;

[0230] Fig. 9 An algorithm for power saving in FL and power boosting in SL according to some example embodiments of the present invention is shown;

[0231] Fig.10 An apparatus according to an example embodiment of the present invention is shown;

[0232] Fig.11 A method according to an example embodiment of the present invention is shown;

[0233] Fig.12 An apparatus according to an example embodiment of the present invention is shown;

[0234] Fig.12 A method according to an example embodiment of the present invention is shown;

[0235] Fig.14 An apparatus according to an example embodiment of the present invention is shown;

[0236] Fig.15 A method according to an example embodiment of the present invention is shown;

[0237] Fig.16 An apparatus according to an example embodiment of the present invention is shown;

[0238] Fig.17 A method according to an example embodiment of the present invention is shown;

[0239] Fig.18 An apparatus according to an example embodiment of the present invention is shown;

[0240] Fig.19 A method according to an example embodiment of the present invention is shown; and

[0241] Fig. 20 An apparatus according to an example embodiment of the invention is shown. DETAILED DESCRIPTION

[0242] Hereinafter, certain embodiments of the present invention are described in detail with reference to the accompanying drawings, wherein, unless otherwise specified, the features of these embodiments may be freely combined with each other. However, it should be clearly understood that the description of certain embodiments is given only by way of example, and it is by no means intended to be understood as limiting the present invention to the disclosed details.

[0243] Furthermore, it should be understood that the apparatus is configured to perform the corresponding method, although in some cases only the apparatus or only the method is described.

[0244] Lower frequency bands are more suitable for wide area coverage due to their lower propagation losses. For mobile data services, HAPS and satellites are expected to use LTE bands or NR frequency range 1 (FR1, i.e., spectrum below 6 GHz) to serve UEs. The antenna arrays on HAPS or satellites generate multiple beams to cover a large service area with the desired antenna gain, thereby achieving high user throughput. A typical scenario is as follows: Figure 1 As shown. The coverage of one beam on the ground can be between 20-100km for HAPS and even larger for LEO satellites. In the case of such large beam coverage, the lowest 15kHz subcarrier spacing (SCS) is the preferred option in the NR OFDM digital basic configuration because the corresponding longest cyclic prefix (CP) allows the maximum timing error tolerance.

[0245] On the other hand, the feeder link requires a wider bandwidth to transmit the aggregated data from multiple beams to the gateway station. In the case of N active beams, each beam has a channel bandwidth of B. C To operate above this, the feeder link will require a bandwidth of B FL >NB C This is Figure 2 An example with seven activated beams is shown in . Since it is difficult to find large bandwidths in the crowded lower frequency bands, the feeder links can use higher frequency spectrum in addition to the frequency bands used for mobile data services.

[0246] For regenerative HAPS and satellites, the PHY / MAC processing of the service link is implemented onboard and the feeder link is designed independently, so the frequency band selection of the feeder link is flexible. However, for bent-pipe HAPS and satellites, the base station is located on the ground, so the feeder link needs to carry the same LTE / NR waveform used by the UE. In order to support the same digital basic configuration in the service link (e.g., 15kHz SCS) for wide area coverage, the feeder link must use the LTE band or the NRFR1 band. (Note: NR does not support 15kHz, 30kHz SCS in FR2, the range is 24.25-52.6GHz). However, these bands do not have enough bandwidth to support the multiple beams required for large coverage.

[0247] Another alternative is to convert the lower frequency LTE / NR waveform (e.g., 15kHz SCS) to a higher frequency in the feeder link so that the frequency carrier from each beam occupies a sub-band in the higher spectrum, such as Figure 2 However, this approach is also problematic because high-frequency (e.g., mmWave band) RF signals are susceptible to distortion caused by phase noise and Doppler effect. The LTE / NR waveform of a small SCS modulated on a high-frequency carrier may be severely corrupted.

[0248] Some example embodiments of the present invention enable a feeder link to use a high frequency band (e.g., >6 GHz, e.g., FR2) with a different SCS than a serving link to support multiple low frequency carriers on a serving link for LTE or NR mobile data services provided by HAPS or satellite.

[0249] Some example embodiments of the present invention involve special processing of baseband IQ data at the satellite end (or on HAPS) of the feeder link. This allows the feeder link to have a wider SCS (and service links working with smaller SCS) and to be able to use wider available bandwidth in the high frequency band. As the SCS increases, the feeder link signal will be robust to channel distortion and phase noise in the high frequency spectrum.

[0250] Some aspects of example embodiments of the invention are summarized below. Some example embodiments of the invention may use only one or more of these aspects, while other example embodiments may use all of these aspects.

[0251] 1. The feeder link can use a high frequency band in FR2 with a larger SCS (e.g., 120 or 240 kHz).

[0252] 2. The service link deploys a smaller SCS (15 or 30kHz) than the feeder link.

[0253] 3. The service link can adopt FR1 to achieve better coverage performance. The service link has M beams, where each beam can be mapped to a single cell in the service link (or mapped to multiple cells in a time division multiplexing manner).

[0254] 4. Satellite circuitry at the NTN satellite maps the LTE or NR timeslots from the HF feeder link into different beams on the serving link.

[0255] a. The mapping of feeder link timeslots to serving link timeslots (and vice versa) is done in a precise manner according to rules to maintain the NR frame structure, subcarrier spacing and carrier bandwidth on the serving link.

[0256] b. A separate control (management) link may instruct the satellite to perform mapping according to rules, and / or the mapping or a portion of the mapping may be based on predefined rules.

[0257] 5. The satellite can map the feeder link time slots on a TDM and / or FDM basis. This can be configured via a management link or can be predefined.

[0258] If only TDM mapping of feeder link timeslots onto serving link beams (timeslots) is employed, the satellite can process incoming feeder link timeslots as they arrive (no buffer capacity is required at the satellite)

[0259] b. If there is a slot buffer available on the satellite (or HAPS), the feeder link slots can also be mapped in FDM mode (see Figure 7 ). In this case, the satellite will buffer the incoming feeder link timeslots and forward all subcarriers (for a given serving link beam mapping) when they are received. Equivalently, on the uplink, buffering will be used to map some subcarriers to different positions in the feeder link timeslots.

[0260] c. The configuration of the time slots transmitted by the management link may be affected by the operator's policy and the available FL bandwidth and number of SL cells.

[0261] 6. The bandwidth of each service link time slot can be divided into m subbands (SL time slot subbands) with the same bandwidth, where m is a positive integer. In the frequency domain, the SL time slot subbands of the time slot do not overlap and are continuous with each other, so that they cover the entire bandwidth of the SL time slot. If m=1, the service link time slot is not divided into different SL time slot subbands. Each feeder link time slot in the feeder link time slot can be mapped to a service link time slot subband in a 1:1 relationship. Therefore, if m>1, multiple feeder link time slots can be mapped to one SL time slot, and vice versa (FDM mapping).

[0262] 7. In some example embodiments, the UE on the serving link does not see any frames /

[0263] Timeslot hopping. However, from the gNB perspective, some timeslots for specific UEs are prohibited in order to schedule a given cell as well as timeslot numbering and timing relationships. Therefore, some software on the gNB may be modified relative to legacy software (e.g., timeslot and frame numbering, timing relationships). However, generally no changes to the gNB HW (AAS) are required. The gNB / NTN gateway can use the existing TN gNB HW. The gateway and gNB can be packaged in one box, or can be separate boxes.

[0264] Figure 3 Satellite circuitry according to some example embodiments of the invention is shown. In an example embodiment, the feeder link uses a 30kHz SCS, while the service link uses a 15kHz SCS. In this example embodiment, a single 40MHz feeder link channel (i.e., with a bandwidth of 40MHz) can support two 20MHz service link beams or cells (i.e., each with a bandwidth of 20MHz). At the satellite, in the DL direction of the service link (i.e., from the satellite to the UE), digital samples from the FL acquired during time T / 2 are transmitted during time T, which reduces the bandwidth of the signal by a factor of 2. A corresponding relationship holds in the UL direction (from the UE via the satellite to the gNB), where digital samples acquired from one service link during time T are transmitted over the feeder link during T / 2.

[0265] exist Figure 3 In an example embodiment of , the satellite processes only the even timeslots (0.5 ms in duration) on the feeder link of one cell and ignores the odd timeslots of one cell. In the DL direction, samples from the even timeslots of 0.5 ms in duration (acquired at twice the rate required on the serving link) are sent over 1 ms, effectively compressing the bandwidth of the OFDM waveform by 2. In the UL direction, for each 1 ms long timeslot, using 15 kHz SCS, the samples acquired over one timeslot are sent over the feeder link over 0.5 ms, which expands the bandwidth of the signal on the feeder link, which now corresponds to 30 kHz SCS. A second 2T2R cell can have the same circuitry, but the circuitry will only process the odd timeslots on the feeder link and ignore the even timeslots on the feeder link.

[0266] exist Figure 3 , the payload controller describes a control or management link (via an RF modem and antenna module "RF mdm / ant") that can program the satellite circuitry for feeder link to service link timeslot mapping (this control link can use a separate radio link).

[0267] Note that the control or management link is optional. Instead, some or all of the mapped parameters may be predefined. If a control signal for one of the predefined parameters is received, the control signal may have a prevalence exceeding the predefined value of that parameter, or vice versa, depending on the implementation.

[0268] The mapping is performed by a resampling function (RSF) at baseband after the received signals have been amplified and down-converted, and before they have been up-converted and amplified. In detail:

[0269] DL: The satellite receives a 30kHz SCS signal with a slot duration of 0.5ms (2 slots in a subframe of T=1ms). After down-conversion to baseband, digital samples sampled at a rate matching the slot duration of the FL (acquired during 0.5ms (during time T / 2)) are sent on the serving link during a 1ms interval after up-conversion (1 slot of 1ms in a subframe of T=1ms during time T).

[0270] UL: Satellite receives 15kHz SCS signal with a slot duration of 1ms. After down-conversion to baseband, digital samples sampled at the service link data rate matching the slot duration of the SL (acquired during 1ms (during time T)) are transmitted on the feeder link 0.5ms (during time T / 2) after up-conversion.

[0271] The memory function may help collect samples on the UL side as the samples are collected for transmission onto the feeder link (FL).

[0272] That is, after resampling, mapping is done on a FL slot-by-slot basis, rather than a symbol-by-symbol basis. Digital samples sampled at a rate matching the slot duration of the FL (acquired during time 0.5 ms or during T / 2 in this example) are transmitted on the serving link after upconversion using a rate matching the slot duration of the serving link (during 1 ms intervals or during time T). Memory may be used to collect the samples and then transmit them later. The Fourier transform property ensures that sample time expansion (compression) results in bandwidth compression (expansion) in the same proportion.

[0273] Scaling of Subcarrier Spacing (SCS)

[0274] Assume T s is the sampling time of the feeder link transmission, so the sampling rate is R = 1 / T s. Let T′ and Δf be the OFDM symbol time and subcarrier spacing (SCS) respectively. Therefore, an OFDM symbol contains N s =T′ / T s consecutive samples, and the nth complex sample (0≤n<N s ) is expressed as

[0275]

[0276] Where N FFT is the FFT size, a k is the modulated data symbol on the kth subcarrier.

[0277] The samples of the OFDM symbol remain the same, but the N samples of one symbol from the feeder link s samples are modulated over a duration of N*T′, where in this particular example N=2. This means that for SL, the new effective sampling rate is 0.5*R=1 / (2T s ), which corresponds to the new sampling time T′ s =2T s The basic FFT size (number of subcarriers) remains unchanged. In particular, the nth sample (0≤n<N s ) can be expressed as

[0278]

[0279] Where Δf′ = 0.5Δf. The new SL waveform has half the SCS and twice the symbol time.

[0280] As described above, some example embodiments of the present invention include baseband signal processing at the satellite end of the feeder link. In the following description, an example embodiment of an NTN gNB with two serving link cells (or beams) is first described, each serving link cell (or beam) having the same bandwidth and subcarrier spacing. In the following, this special case will be generalized to multiple cells in the serving link.

[0281] like Figure 4 As shown, there is an NTN system (or HAPS) with 2 NR cells in the service link, and each service link time slot has a 20MHz bandwidth and a 15kHz subcarrier spacing. In this configuration, the FL must support 212 RBs per 1ms and maintain the time slot timing relationship. In the FL, a TDM-like time slot mapping is deployed, where each service beam is time-division multiplexed, and the FL uses a larger SCS. Therefore, the gNB uses a 40MHz wide channel for the FL with a 30kHz SCS.

[0282] For DL ​​transmissions from the gNB to the UE, the satellite receives the broadband feeder signal, down-converts it to baseband, acquires digital samples at a sampling rate that matches the FL rate (time slot duration on FL), stores the samples in memory, modulates, and forwards them on the serving link cell. The corresponding digital samples acquired during time T / 2 on FL are transmitted on each serving link during time T, which reduces the bandwidth of the signal by a factor of 2. In this example embodiment, the serving link cell is treated as a beam direction for scheduling purposes. Even time slots go into cell 1 (cell 1 ), and the odd time slots enter cell 2 (cell 2 ).

[0283] From the gNB's perspective, there are scheduling constraints. Cell 1 can only be scheduled in even slots, and cell 2 can only be scheduled in odd slots. In some example embodiments, there are no such restrictions from the UE's perspective, because the UE does not see any frame / slot discontinuity. That is, the UE receives a serving signal with 15kHz SCS and 1ms slot duration, while for each UE, the gNB sends out a corresponding signal with 30kHz SCS and 0.5ms slot duration alternately.

[0284] Since there is a difference in slot numbering from the UE and gNB perspective, due to resampling (multiplexing / demultiplexing) at the satellite, the gNB can renumber the slots so that the UEs in the corresponding cell do not see a jump in slot numbering or any missing slots in the NR frame structure. This may result in changes to the gNB scheduler and associated updates to timing constraints (i.e., HARQ timing, RACH timing, etc.) to reflect this renumbering. These changes do not affect the RF waveform, just the data carried by the RF signal.

[0285] In uplink transmission from UE to gNB, a corresponding function is used: the satellite receives the time slots from the serving link and the staggered time slots are sent down on the FL to the satellite gateway. Figure 5 It shows how to map time slots from FL to SL and vice versa. Time compression of time slots (respectively OFDM symbols) on FL increases the SCS of the FL waveform and makes it feasible to use mmWave spectrum on FL. Figures 5 to 7 In the feeder link time slot and service link time slot (or Figure 7 The service link time slot subbands in the feeder link are numbered according to the numbering on the feeder link. In practice, the time slots on the service link can be renumbered so that the numbering of the service link time slots on each service link is continuous. For example, Figure 5On the left side, the representation of the service link time slots ("Time Slot 0", "Time Slot 2", "Time Slot 4") of cell 1 indicates that the signals in the service link of cell 1 come from FL Time Slot 0, FL Time Slot 2, and FL Time Slot 4, but these signals are mapped to SL Time Slot 0, SL Time Slot 1, and SL Time Slot 2.

[0286] According to some example embodiments, the gNB is aware of this FL to SL timeslot mapping when performing scheduling so that the SL timeslots will appear contiguous to the UE. Figure 5 In the example, if a UE in cell 1 is allocated SL slots 0 and 1, the gNB must send a signal for this UE in FL slots 0 and 2.

[0287] Resampling Function (RSF) [See Figure 3 and Figure 5 ]

[0288] The functionality of the resampling function can be described as multiplexing / demultiplexing on the satellite to correctly map the service link time slot (or time slot sub-band) on the feeder link time slot and vice versa. During this multiplexing / demultiplexing, the digital samples are compressed (from SL to FL) or spread in time (from FL to SL), which changes the frequency content of the signal.

[0289] DL: In the case of two SL cells, the satellite receives a 30kHz SCS signal with a slot duration of 0.5ms. After down-conversion to baseband, the digital samples (sampled at a rate matching the feeder link data rate) acquired during T / 2 (here 0.5ms) are sent on the serving link during time T (1ms intervals) after up-conversion. According to the properties of the Fourier transform, a dilation in time corresponds to a compression of the spectrum by the same factor. Using a sampling rate f 1 , N obtained during 0.5ms 1 The digital samples are converted into an analog signal with a span of 1ms.

[0290] UL: The satellite receives a 15kHz SCS OFDM signal with a slot duration of 1ms (14 OFDM symbols). After down-conversion to baseband, the digital samples received during time T (here 1ms), acquired at a rate matching the SL data rate, are sent on the feeder link within T / 2 (here 0.5ms) after up-conversion.

[0291] An advantage of the method of some example embodiments of the invention is that no changes to the gNB HW (AAS) are required. The gNB and NTN Gateway can be placed in one box. Only software changes are required in the higher layers (e.g. frame numbering, timing relationships).

[0292] Expand to multiple cells in the service link

[0293] In the following, some aspects of the present invention will be discussed, in particular how to implement TDM and FDM mapping of time slots.

[0294] Conversion from FL to SL.

[0295] The feeder link (FL) characteristics (available bandwidth, SCS) determine the available capacity of the serving link according to the available bandwidth and SCS of the SL cell. For example, the following principle can be used for FL to SL mapping.

[0296] 1. On the FL side, the mapping between SL and FL is done on a FL timeslot-by-FL basis. On the SL side, the mapping is done on a SL timeslot-by-SL timeslot subband basis.

[0297] 2. The mapping pattern can be configured over the period of one subframe (1ms in NR and LTE). Then, the SL to FL mapping can be the same for different subframes.

[0298] 3. If P is the number of RBs per serving link cell in 1 ms, and there are N serving link cells, then the feeder link bandwidth should be such that it can support ≥ N*P RBs in 1 ms.

[0299] 4. If FL uses a higher SCS (e.g., 120kHz or 240kHz) and has P per slot f resource blocks, then P s The number of RBs in a time slot of a given SL cell is represented by Where N is the number of serving link cells (or beams) served simultaneously, k is the ratio of the SCS of the FL to the SCS of the SL,

[0300] a. Using the above relationship and the SCS of the SL, the bandwidth of the SL can be determined.

[0301] Tables 3 and 4 show examples of different service link (SL) bandwidths and mapping for a 100 MHz wide feeder link NR carrier. Figure 6 and Figure 7 Describes how to perform mapping for different configurations.

[0302] The number of RBs per FL time slot in a cell (P f ) and the number of RBs per SL slot (P s ) has the following relationship: P S =mP f, where m is a positive integer. When m = 1, one SL slot of a cell can be mapped exactly to one FL slot, and the mapping can be performed for N cells in a TDM manner. The FL slots of the same cell are staggered every N slots in the feeder link, as Figure 6 shown.

[0303] When m>1, P in SL s The bandwidth of RBs is divided into m subbands (time slot subbands), each subband has P f RBs. Since one slot subband in SL has the same number of RBs as in FL, one subband in one SL slot can be mapped exactly to one FL slot. The m slot subbands in one SL slot will be mapped to m FL slots. This frequency domain slot mapping can be performed on top of the N slot interleaving structure for the same cell in FL. The consecutive m slot subbands in the same SL slot can be mapped to the interleaved FL slots of the cell according to a given order (e.g., consecutively). An example such as Figure 7 As shown, the SL bandwidth consists of two sub-bands (m=2), and four cells (N=4) are multiplexed on the FL time slot.

[0304]

[0305]

[0306] Table 3: 100 MHz FL mapping for different combinations of SL and SCS.

[0307]

[0308] Table 4: 50 MHz FL mapping for different combinations of SL and SCS.

[0309] Figure 6 and Figure 7 Depicted is how the mapping is performed for different configurations using 100MHz FL bandwidth and 120kHz SCS, with 66RB and 0.125ms slot duration. The right side of each figure shows how the feeder link (FL) slot is mapped onto the service link beam. Figure 6In the FL, 4 service link (SL) cells are supported. Each SL uses 25MHz bandwidth and 30kHz SCS, with 65RBs and 0.5ms slot duration. In this case, m=1, and one SL slot is mapped to one FL slot. Over a 0.5ms period, one SL slot from each of the 4 cells is mapped to the FL slot in a TDM manner, that is, 4 SL slots from the 4 cells are interleaved over 4 consecutive FL slots. Of the 66 available RBs in the FL slot, only 65 are used for SL data. The 66th RB can be left empty or used for time / frequency alignment between the feeder link and the gateway station.

[0310] exist Figure 7 In the NR standard, FL supports 4 SL cells. Each service link uses 25MHz bandwidth and 15kHz SCS with 133RBs and 1ms slot duration. In this case, m=2, that is, one SL slot includes two SL slot subbands. The two SL slot subbands of one SL slot are mapped to two FL slots. Each of the two SL slot subbands includes 66 RBs. Here, the time slots on the feeder link are multiplexed in both TDM and FDM modes to efficiently use the available spectrum. Over a 1ms period, two subbands of one SL slot from each of the 4 cells are mapped to two consecutive staggered FL slots of the cell. Note that in the NR standard, the 25MHz bandwidth has 133RBs for 15kHZ SCS. However, only 132 RBs are available in the SL here because FL can only support 132 RBs for this mapping scheme (66*2=132, see Table 3).

[0311] like Figures 5 to 7As shown in the example of , typically, the rule describing the mapping between the FL time slot and the SL time slot or the SL time slot subband indicates that the FL time slot that is earlier in time on the FL signal corresponds to the SL time slot that is earlier in time on the corresponding SL time slot. In detail, typically, the rule indicates that, for each cell in a plurality of cells, the corresponding number m of feeder link downlink time slots corresponds to m time slot subbands in the corresponding service link downlink time slot of the corresponding cell, m being a positive integer; the feeder link downlink time slots are arranged so that the m feeder link downlink time slots corresponding to the m subbands in the corresponding service link downlink time slot of the corresponding cell are subsequent in the feeder link downlink time slot of the corresponding cell; and the time slot subbands for the first service link downlink time slot in the service link downlink time slot of the corresponding cell and the time slots for the second service link downlink time slot in the service link downlink time slot of the corresponding cell for each pair of time slots of a subband: if the rule indicates that, on a service link between the satellite and the corresponding cell, a first service link downlink time slot in the service link downlink time slots of the corresponding cell is earlier in time than a second service link downlink time slot in the service link downlink time slots of the corresponding cell, then in the feeder link downlink signal, a feeder link downlink time slot corresponding to a time slot subband of the first service link downlink time slot in the service link downlink time slots of the corresponding cell is arranged to be earlier in time than a feeder link downlink time slot corresponding to a time slot subband of the second service link downlink time slot in the service link downlink time slots of the corresponding cell.

[0312] In addition, generally, a time sequence of FL time slots corresponding to one SL time slot of a cell may correspond to a subband index sequence of time slot subbands. In detail: Generally, the rule indicates that: for each service link downlink time slot in the service link downlink time slots of the corresponding cell, for each pair of time slot subbands of a first time slot subband of the corresponding service link downlink time slot and a second time slot subband of the corresponding service link downlink time slot, if the first time slot subband has a higher subband index than the second time slot subband, in the feeder link downlink signal, the feeder link downlink time slot corresponding to the first time slot subband is arranged to be earlier in time than the feeder link downlink time slot corresponding to the second time slot subband. time slot; or the rule indicates: for each service link downlink time slot in the service link downlink time slot of the corresponding cell, for each pair of time slot subbands of the third time slot subband of the corresponding service link downlink time slot and the fourth time slot subband of the corresponding service link downlink time slot, if the third time slot subband has a higher subband index than the fourth time slot subband, then in the feeder link downlink signal, the feeder link downlink time slot corresponding to the fourth time slot subband is arranged to be earlier in time than the feeder link downlink time slot corresponding to the third time slot subband.

[0313] like Figure 3 As shown, a separate management link (control link, connected to the payload controller in the figure) can be used to program the FL and SL time slot mapping and timing. For a given feeder link bandwidth configuration, different options for the number of SL SCS and SL cells can be implemented using the management link as described above. In addition, this link can be used for timing and frequency alignment at the satellite.

[0314] Enhanced power boost and power saving on service links

[0315] In some example embodiments of the invention, active slot mapping may be used to change the bandwidth of cells in the SL. This may be useful when there are more cells (or beams) in the SL than the FL bandwidth can support, but the cells (or beams) have low load or are idle. An example is Figure 8 This is particularly useful if some buffering function is available on the satellite (FDM type slot mapping requires a buffering function anyway).

[0316] In detail, Figure 8 An example is shown where the FL is designed to support 4 cells in the SL (as shown in the first column of Table 3), but there are 6 cells to be served on the serving link side. In this case, if the resource utilization is low, the gNB / terrestrial gateway (under the guidance of the radio intelligent controller or some other RAN management function) and the satellite can be configured with the timeslot configuration specified in the second column from the left of Table 3. Since there are only six cells to be served on the SL, 2 timeslots on the FL are set to empty. The management link conveys this configuration from the gNB to the satellite via the terrestrial gateway.

[0317] The management link (or control link) can transmit information from the ground gateway to the satellite for notifying power boost (e.g., no boost, priority boost, etc.). To help with power boost, the network can be configured to send some common signals on the beam, such as SSB, SIB1, so that they either all appear at the same time (or subframe) or at different times (or subframes).

[0318] Power boosting can also be applied to scenarios where the FL bandwidth can support all SL cells (or beams), but some beams in the SL are not transmitted by the satellite due to low load, as indicated by the gateway (gNB) via a management link. In particular, the operation of the scheduler can be optimized (by the radio intelligence controller or other RAN management functions) to create empty subframes (i.e., try to group together signals to all UEs in the same subframe for a given SL cell or beam). For example, if using Figure 7In the configuration shown, where the FL supports 4 cells in the SL and the load on some cells is low, the gNB can use selective blanking of time slots to optimize power. In this case, the satellite is able to blank the corresponding SL cell transmissions and reallocate the available power to the active SL beams. The increased power can be used to better serve cell edge UEs or to improve the demodulation performance of the UE. When the satellite receives a blank slot on the FL, the power reallocation and blanking can be communicated by the management link or inferred by the satellite. The algorithm is as follows Fig. 9 Note that the creation of blank subframes is preferable for dynamic power reallocation because the gNB can coordinate the power boost between different SLs more efficiently.

[0319] Fig.10 An apparatus according to an exemplary embodiment of the invention is shown. The apparatus may be a satellite (or HAPS) or an element thereof. Fig.11 A method according to an exemplary embodiment of the present invention is shown. Fig.10 The device can perform Fig.11 method, but not limited to this method. Fig.11 The method can be Fig.10 The present invention is performed by a device, but is not limited to being performed by the device.

[0320] The apparatus includes a receiving component 110, a mapping component 120, and a sending component 130. The receiving component 110, the mapping component 120, and the sending component 130 may be a receiving component, a mapping component, and a sending component, respectively. The receiving component 110, the mapping component 120, and the sending component 130 may be a receiver, a mapper, and a sender, respectively. The receiving component 110, the mapping component 120, and the sending component 130 may be a receiving processor, a mapping processor, and a sending processor, respectively.

[0321] The receiving means 110 receives a downlink feeder signal on a feeder link (S110). The downlink feeder signal comprises a feeder link downlink time slot in the time domain, the feeder link downlink time slot having a feeder link bandwidth in the frequency domain, the feeder link bandwidth having a feeder link subcarrier spacing. The feeder link downlink time slot has a feeder link time slot duration. Each feeder link time slot in the feeder link time slot comprises a corresponding symbol.

[0322] The component 120 for mapping maps each feeder link downlink time slot in the feeder link downlink time slot to a corresponding time slot subband in the corresponding service link downlink time slot according to a rule (S120). The service link downlink time slot has a service link time slot duration. The service link time slot duration is longer than the feeder link time slot duration. Each time slot subband in the time slot subband includes symbols of the feeder link downlink time slot mapped to the corresponding time slot subband.

[0323] The component 130 for sending sends a corresponding downlink service signal (S130) on each service link in a plurality of service links. Each downlink service signal in the downlink service signal includes one or more corresponding service link downlink time slots in the service link downlink time slot in the time domain. Each service link downlink time slot in the service link downlink time slot includes m time slot subbands in the time slot subband in the frequency domain, where m is a positive integer. In each service link downlink time slot in the service link downlink time slot, the m time slot subbands are arranged in the frequency domain to have the same bandwidth and have a service link subcarrier spacing. In each service link downlink time slot in the service link downlink time slot, in the frequency domain, the m time slot subbands do not overlap, are continuous with each other, and cover the entire service link bandwidth of the corresponding service link downlink time slot. The feeder link subcarrier spacing is greater than the service link subcarrier spacing.

[0324] Fig.12 An apparatus according to an example embodiment of the present invention is shown. The apparatus may be a base station (e.g., gNB, eNB) or an element thereof. Fig.13 A method according to an exemplary embodiment of the present invention is shown. Fig.12 The device can perform Fig.13 method, but not limited to this method. Fig.13 The method can be Fig.12 The present invention is performed by a device, but is not limited to being performed by the device.

[0325] The device includes a component 210 for providing and a component 220 for arranging. The component 210 for providing and the component 220 for arranging can be a providing component and an arranging component respectively. The component 210 for providing and the component 220 for arranging can be a provider and an arranger respectively. The component 210 for providing and the component 220 for arranging can be a providing processor and an arranging processor respectively.

[0326] The means 210 for providing provides a corresponding downlink signal for each of the plurality of cells (S210). The corresponding downlink signal is to be transmitted in a corresponding one or more feeder link downlink time slots on a feeder link to a satellite.

[0327] The means for arranging 220 arranges the feeder link time slots of the plurality of cells in a staggered manner according to a rule (S220). Thus, the means for arranging obtains a feeder link downlink signal. The feeder link downlink signal may be transmitted on the feeder link.

[0328] Fig.14 An apparatus according to an example embodiment of the present invention is shown. The apparatus may be a base station (e.g., gNB, eNB) or an element thereof. Fig.15 A method according to an exemplary embodiment of the present invention is shown. Fig.14 The device can perform Fig.15 method, but not limited to this method. Fig.15 The method can be Fig.14 The present invention is performed by a device, but is not limited to being performed by the device.

[0329] The device includes a component 310 for monitoring and a component 320 for scheduling. The component 310 for monitoring and the component 320 for scheduling can be a monitoring component and a scheduling component, respectively. The component 310 for monitoring and the component 320 for scheduling can be a monitor and a scheduler, respectively. The component 310 for monitoring and the component 320 for scheduling can be a monitoring processor and a scheduling processor, respectively.

[0330] The monitoring component 310 monitors whether the bandwidth of the feeder link is sufficient to send a corresponding downlink signal to each of the multiple cells via the feeder link, and keeps at least one feeder link time slot on the feeder link empty (S310). For each cell, the corresponding downlink signal is sent on the feeder link in the corresponding one or more feeder link time slots.

[0331] If the bandwidth of the feeder link is sufficient (S310=Yes), the means for scheduling 320 schedules the sending of the downlink signal so that at least one of the feeder link time slots is empty (S320).

[0332] Fig.14 The device can be used with Fig.12 The same device. Fig.15 Methods may include Fig.13 method and vice versa.

[0333] Fig.16 An apparatus according to an exemplary embodiment of the present invention is shown. The apparatus may be a controller or an element thereof. Fig.17 A method according to an exemplary embodiment of the present invention is shown. Fig.16 The device can perform Fig.17 method, but not limited to this method. Fig.17 The method can be Fig.16The present invention is performed by a device, but is not limited to being performed by the device.

[0334] The apparatus comprises means for indicating 410. The means for indicating 410 may be an indicating means. The means for indicating 410 may be an indicator. The means for indicating 410 may be an indication processor.

[0335] The indicating component 410 indicates at least one of a feeder time slot duration on a satellite application feeder link time slot, a service time slot duration on a service link time slot, a feeder link subcarrier spacing between feeder link time slots, a service link subcarrier spacing between service link time slots, and a rule for mapping feeder link time slots to service link time slots (S410).

[0336] Fig.18 An apparatus according to an exemplary embodiment of the present invention is shown. The apparatus may be a controller or an element thereof. Fig.19 A method according to an exemplary embodiment of the present invention is shown. Fig.18 The device can perform Fig.19 method, but not limited to this method. Fig.19 The method can be Fig.18 The present invention is performed by a device, but is not limited to being performed by the device.

[0337] The device includes a component 510 for monitoring and a component 520 for notifying. The component 510 for monitoring and the component 520 for notifying can be a monitoring component and a notification component, respectively. The component 510 for monitoring and the component 520 for notifying can be a monitor and a notifier, respectively. The component 510 for monitoring and the component 520 for notifying can be a monitoring processor and a notification processor, respectively.

[0338] The means for monitoring 510 monitors whether information is received (S510). The information notifies that at least one of the plurality of feeder link time slots on the feeder link is empty. If information that one of the feeder link time slots is empty is received (S510=Yes), the means for notifying 520 notifies the satellite that one of the feeder link time slots is empty (S520).

[0339] Fig.18 The device can be used with Fig.16 The same device. Fig.19 Methods may include Fig.17 method and vice versa.

[0340] Fig. 20An apparatus according to an example embodiment of the present invention is shown. The apparatus comprises at least one processor 810, at least one memory 820 comprising computer program code, and the at least one processor 810 is arranged to, together with the at least one memory 820 and the computer program code, cause the apparatus to at least perform the operation according to Fig.11 , Fig.13 , Fig.15 , Fig.17 and Fig.19 At least one of and the related described methods.

[0341] Some example embodiments are explained with respect to 5G networks. However, the present invention is not limited to 5G. It can also be used in other communication networks using satellites or HAPS, where different digital technologies can be applied for feeder links and service links, for example in next generation 3GPP networks such as 6G or 7G, or in modified versions of previous 3GPP networks such as 4G. In particular, the present invention is not limited to the digital basic configuration currently specified for NR. Other digital basic configurations can be used to supplement or replace the digital basic configuration specified for NR.

[0342] An information fragment may be sent from one entity to another entity in one or more messages. Each of these messages may include another (different) information fragment.

[0343] The names of network elements, network functions, protocols and methods are based on current standards. In other versions or other technologies, the names of these network elements and / or network functions and / or protocols and / or methods may be different, as long as they provide corresponding functions. The same applies to terminals.

[0344] Unless otherwise stated or otherwise clear from the context, the statement that two entities are different means that they perform different functions. This does not necessarily mean that they are based on different hardware. That is, each entity described in this specification can be based on different hardware, or some or all entities can be based on the same hardware. This does not necessarily mean that they are based on different software. That is, each entity described in this specification can be based on different software, or some or all entities can be based on the same software. Each entity described in this specification can be deployed in the cloud.

[0345] From the above description, it should be clear that the exemplary embodiments of the present invention provide, for example, a satellite or HAPS or a component thereof, an apparatus for implementing the satellite or HAPS or a component thereof, a method for controlling and / or operating the satellite or HAPS or a component thereof, and (multiple) computer programs for controlling and / or operating the satellite or HAPS or a component thereof, and a medium that carries such (multiple) computer programs and forms (multiple) computer program products. From the above description, it should be clear that the exemplary embodiments of the present invention provide, for example, a RAN node (such as a base station, such as a gNB or eNB, etc.) or a component thereof, an apparatus for implementing the RAN node or a component thereof, a method for controlling and / or operating the RAN node or a component thereof, and (multiple) computer programs for controlling and / or operating the RAN node or a component thereof, and a medium that carries such (multiple) computer programs and forms (multiple) computer program products. Based on the above description, it should be clear that example embodiments of the present invention provide, for example, a controller or components thereof, an apparatus implementing the controller or components thereof, a method for controlling and / or operating the controller or components thereof, and (multiple) computer programs for controlling and / or operating the controller or components thereof, as well as a medium that carries such (multiple) computer programs and forms (multiple) computer program products.

[0346] As non-limiting examples, implementation of any of the above blocks, devices, systems, techniques, or methods includes implementation as hardware, software, firmware, dedicated circuits or logic, general purpose hardware or controllers or other computing devices, or some combination thereof. Each entity described in this specification can be embodied in the cloud.

[0347] It should be understood that what has been described above is what is currently considered to be the preferred exemplary embodiment of the present invention. However, it should be noted that the description of the preferred exemplary embodiment is given by way of example only, and various modifications can be made without departing from the scope of the present invention as defined by the appended claims.

[0348] The phrase "at least one of A and B" includes option A only, option B only, and both option A and option B. The terms "first X" and "second X" include the following options: "first X" is the same as "second X" and "first X" is different from "second X", unless otherwise specified.

Claims

1. A device for communication, comprising: one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: receiving (S110) a downlink feeder signal on a feeder link, the downlink feeder signal comprising a feeder link downlink time slot in the time domain, the feeder link downlink time slot having a feeder link bandwidth in the frequency domain, the feeder link bandwidth having a feeder link subcarrier spacing; According to a rule, mapping (S120) each feeder link downlink time slot in the feeder link downlink time slot to a corresponding time slot subband in a corresponding service link downlink time slot; On each of the plurality of service links, a corresponding downlink service signal is transmitted (S130), wherein Each of the downlink service signals comprises, in the time domain: a corresponding one or more of the service link downlink time slots; Each of the serving link downlink time slots comprises, in the frequency domain: m time slot subbands of the time slot subbands, where m is a positive integer; In each of the serving link downlink time slots, the m time slot subbands are arranged in the frequency domain to have the same bandwidth and have a serving link subcarrier spacing; In each of the serving link downlink time slots, in the frequency domain, the m time slot subbands do not overlap, are continuous with each other, and cover the entire serving link bandwidth of the corresponding serving link downlink time slot; wherein The feeder link downlink time slot has a feeder link time slot duration; The serving link downlink timeslot has a serving link timeslot duration that is longer than the feeder link timeslot duration; The feeder link subcarrier spacing is greater than the serving link subcarrier spacing; Each of the feeder link downlink time slots comprises a corresponding symbol; Each of the time slot sub-bands includes the symbols of the feeder link downlink time slots mapped to the corresponding time slot sub-band.

2. The apparatus of claim 1 , wherein the instructions, when executed by the one or more processors, cause the apparatus to perform: On each of the plurality of service links, a corresponding uplink service signal is received; in the time domain, a corresponding service link uplink time slot is included, the corresponding service link uplink time slot has the service link bandwidth in the frequency domain, and the service link bandwidth includes: corresponding m time slot subbands in the time slot subbands arranged with the serving link subcarrier spacing; According to the rule, mapping each of the m time slot subbands in each of the serving link uplink time slots to a corresponding feeder link uplink time slot; Arranging the feeder link uplink time slots in the time domain with the feeder link subcarrier spacing in the frequency domain according to the rule to obtain an uplink feeder signal; The uplink feeder signal is transmitted on the feeder link, wherein Each of the uplink service signals comprises in the time domain: a corresponding one or more of the service link uplink time slots; The feeder link uplink time slot has the feeder link time slot duration; The serving link uplink timeslot has the serving link timeslot duration; Each of the serving link uplink time slots comprises a corresponding symbol; Each of the feeder link uplink timeslots includes the symbols of the serving link uplink timeslot mapped to the corresponding feeder link uplink timeslot.

3. The apparatus of claim 2, wherein the instructions, when executed by the one or more processors, further cause the apparatus to perform the mapping of each time slot sub-band in each of the serving link uplink time slots onto the corresponding feeder link uplink time slot by: down-converting said serving link uplink timeslots of said corresponding timeslot sub-band to a baseband uplink serving signal; sampling the baseband uplink service signal at the service link subcarrier spacing to obtain digital uplink samples corresponding to the corresponding time slot subband; The digital uplink samples are upconverted and compressed in time to obtain the corresponding feeder link uplink time slots. The apparatus of claim 1 , wherein the feeder link has a higher carrier frequency than the serving link.

5. The apparatus of claim 1 , wherein the instructions, when executed by the one or more processors, further cause the apparatus to perform the mapping of each of the feeder link downlink time slots to the corresponding time slot subband in the corresponding service link downlink time slot by: down-converting the feeder link downlink time slot to a baseband downlink feeder signal; sampling the baseband downlink feeder signal at the feeder link subcarrier spacing to obtain digital downlink samples corresponding to corresponding feeder link downlink time slots; For each of the service links: determining, according to the rule, corresponding digital downlink samples among the digital downlink samples; upconverting and spreading the determined digital downlink samples in time, To obtain the corresponding time slot subband; According to the rule, the time slot subbands belonging to the corresponding serving link downlink time slot are combined to obtain the corresponding serving link downlink time slot.

6. An apparatus according to claim 1, wherein the instructions, when executed by the one or more processors, cause the apparatus to perform the mapping of each feeder link downlink time slot in the feeder link downlink time slot to the corresponding service link downlink time slot, so that on each service link in the service links, the numbers of the corresponding service link downlink time slots are continuous, and the corresponding service link downlink time slots are continuous in time on the corresponding service links.

7. The apparatus of claim 1, wherein the instructions, when executed by the one or more processors, cause the apparatus to perform: On a control link, information is received about at least one of the feeder time slot duration, the service time slot duration, the feeder link subcarrier spacing, the service link subcarrier spacing, and the rules for mapping the feeder link downlink time slot to the service link downlink time slot on the time slot subband.

8. The device according to claim 1, wherein At least one of the feeder slot duration, the service slot duration, the feeder link subcarrier spacing, the service link subcarrier spacing, and the rules for mapping the feeder link downlink slot to the service link downlink slot on the slot subband are predefined.

9. The apparatus according to any one of claims 1 to 8, wherein the instructions, when executed by the one or more processors, cause the apparatus to execute: detecting whether one of the feeder link downlink time slots is empty; If one of the feeder link downlink time slots is empty: reducing the transmit power of the serving link downlink timeslot on which the one of the feeder link downlink timeslots is mapped; and Boosting the power of one or more of the serving link downlink time slots, wherein the one of the feeder link downlink time slots is not mapped to any of the one or more of the serving link downlink time slots.

10. The apparatus of claim 9, wherein the detecting comprises: It is detected whether information notifying that the one of the feeder link downlink time slots is empty is received.

11. A method for communication, comprising: receiving (S110) a downlink feeder signal on a feeder link, the downlink feeder signal comprising a feeder link downlink time slot in the time domain, the feeder link downlink time slot having a feeder link bandwidth in the frequency domain, the feeder link bandwidth having a feeder link subcarrier spacing; According to a rule, mapping (S120) each feeder link downlink time slot in the feeder link downlink time slot to a corresponding time slot subband in a corresponding service link downlink time slot; On each of the plurality of service links, a corresponding downlink service signal is transmitted (S130), wherein Each of the downlink service signals comprises, in the time domain: a corresponding one or more of the service link downlink time slots; Each of the serving link downlink time slots comprises, in the frequency domain: m time slot subbands of the time slot subbands, where m is a positive integer; In each of the serving link downlink time slots, the m time slot subbands are arranged in the frequency domain to have the same bandwidth and have a serving link subcarrier spacing; In each of the serving link downlink time slots, in the frequency domain, the m time slot subbands do not overlap, are continuous with each other, and cover the entire serving link bandwidth of the corresponding serving link downlink time slot; wherein The feeder link downlink time slot has a feeder link time slot duration; The serving link downlink timeslot has a serving link timeslot duration that is longer than the feeder link timeslot duration; The feeder link subcarrier spacing is greater than the serving link subcarrier spacing; Each of the feeder link downlink time slots comprises a corresponding symbol; Each of the time slot sub-bands includes the symbols of the feeder link downlink time slots mapped to the corresponding time slot sub-band.

12. A computer program product comprising a set of instructions which, when executed on a device, are configured to cause the device to perform the method according to claim 11.

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