Hybrid MIMO over Multiple Multi-Antenna Satellites

Abstract

A method includes receiving a first signal by a first antenna; receiving a second signal by a second antenna; and forwarding a feeder signal to a base station, wherein the feeder signal is based on the first signal and the second signal, wherein a polarization angle of the second antenna is different from a polarization angle of the first antenna.

Description

Technical Field

[0001] The present disclosure relates to providing communication services via non-terrestrial networks.

[0002] abbreviation

[0003] 3GPP: Third Generation Partnership Project

[0004] 5G / 6G / 7G: fifth generation / sixth generation / seventh generation

[0005] CQI: Channel Quality Indicator

[0006] CU: Centralized Unit

[0007] DDC: Digital Down Conversion

[0008] DL: Downlink

[0009] DMRS: Demodulation Reference Signal

[0010] DU: Distributed Unit

[0011] IoT: Internet of Things

[0012] L1 / L2: Layer 1 (PHY) / Layer 2 (MAC)

[0013] LTE: Long Term Evolution

[0014] MAC: Media Access Control

[0015] MCS: Modulation Coding Scheme

[0016] MIMO: Multiple Input and Multiple Output

[0017] MRC: Maximum Ratio Combining

[0018] NR: New Wireless

[0019] NT: Network Terminal

[0020] NTN: Non-Terrestrial Network

[0021] PHY: Physical layer

[0022] PRB: Physical Resource Block

[0023] RF: Radio Frequency

[0024] RU: Wireless Unit

[0025] SNR: Signal-to-Noise Ratio

[0026] SRS: Sounding Reference Signal

[0027] TA: Timing ahead

[0028] TM: Transfer Mode

[0029] TN: Terrestrial Network

[0030] UE: User Equipment

[0031] UL: Uplink Background Art

[0032] In Rel-17 and Rel-18, 3GPP defined extensions to its New Radio (NR) and LTE IoT standards to optimize the use of NTN. In addition, some companies are building NTN solutions based on earlier 3GPP standards without specific NTN extensions.

[0033] In the so-called "transparent payload architecture," a non-terrestrial platform (satellite) acts as an analog RF repeater for RF signals generated by base stations (e.g., gNBs or eNBs) and terminals (e.g., UEs) located on the ground. The non-terrestrial platform receives the NR-Uu signals via a feeder link and, after frequency conversion / amplification, forwards them to the terminal via a serving link, and vice versa.

[0034] Due to the large distances between terminals and non-terrestrial platforms (e.g., 500-1500 km for low-Earth orbit satellites), NTNs typically must contend with challenging link budgets, resulting in low achievable data rates. A promising approach to improving transmission reliability and / or achievable data rates over terrestrial networks is to utilize multiple antennas for transmission and reception. The use of multiple antennas in NTNs is described, for example, in WO 2021 / 030046 A1, "Satellite MIMO Systems."

[0035] In a transparent payload architecture, digital processing of multiple antenna streams is performed by a base station located on the ground. Multi-antenna processing requires precise time synchronization between antenna streams. Due to the long and variable distances between base stations and non-terrestrial platforms, precise time synchronization is difficult to achieve in an NTN, especially when antenna streams are transmitted and received via different non-terrestrial platforms. An antenna stream consists of sampled signals transmitted and received by a single beam on the satellite. A single beam can be formed by multiple antenna elements.

[0036] Some space mobile systems are designed to be compatible with existing UEs (mobile phones) running on 3GPP LTE and 5G New Radio standards. However, the satellite distance to the UE can be as high as 1500 km, which is more than 20 times the maximum distance between the eNB / gNB and the UE in terrestrial LTE / 5G NT systems. Maintaining the high performance of existing UEs (phones) without increasing UE power is a significant challenge.

[0037] WO 2021 / 030046 A1 describes a "satellite MIMO system" using multiple beams from a single satellite and / or multiple distributed satellites. US 2020 / 412440 A1 describes a system for transmitting / receiving via multiple satellites using a selector / diversity combiner, for example, to mitigate scintillation. Summary of the Invention

[0038] The object of the present invention is to improve the prior art.

[0039] According to a first aspect of the present invention, there is provided an apparatus comprising:

[0040] First antenna,

[0041] a second antenna, wherein a polarization angle of the second antenna is different from a polarization angle of the first antenna;

[0042] one or more processors; and

[0043] A memory storing instructions that, when executed by one or more processors, cause the apparatus to perform:

[0044] receiving a first signal by a first antenna;

[0045] receiving a second signal by a second antenna;

[0046] A feeder signal is forwarded to a base station, wherein the feeder signal is based on the first signal and the second signal.

[0047] The feeder signal may include a first signal and a second signal.

[0048] The instructions, when executed by one or more processors, may also cause the apparatus to perform:

[0049] combining the first signal and the second signal into a single signal; wherein

[0050] The feeder signal comprises this single signal.

[0051] The feeder signal may not include the first signal received by the first antenna; and / or the feeder signal may not include the second signal received by the second antenna.

[0052] According to a second aspect of the present invention, there is provided an apparatus comprising:

[0053] First antenna;

[0054] a second antenna, wherein a polarization angle of the second antenna is different from a polarization angle of the first antenna;

[0055] one or more processors, and

[0056] A memory storing instructions that, when executed by one or more processors, cause the apparatus to perform:

[0057] receiving a first signal by a first antenna;

[0058] forwarding the first signal to a base station;

[0059] monitoring whether a command to switch to the second antenna is received from the base station;

[0060] If the command is received, prohibiting forwarding of the first signal;

[0061] receiving a second signal by a second antenna;

[0062] If the command is received, a second signal is forwarded to the base station.

[0063] According to a third aspect of the antenna, there is provided an apparatus comprising:

[0064] one or more processors, and

[0065] A memory storing instructions that, when executed by one or more processors, cause the apparatus to perform:

[0066] receiving a first feeder signal from a first satellite;

[0067] receiving a second feeder signal from a second satellite different from the first satellite;

[0068] The first combined signal and the second combined signal are combined by MIMO processing, wherein

[0069] The first feeder signal includes an indication that the first feeder signal is based on a third signal from the terminal;

[0070] the second feeder signal including an indication that the second feeder signal is based on a fourth signal from the terminal;

[0071] The first combined signal is based on the first feeder signal;

[0072] The second combined signal is based on the second feeder signal.

[0073] The first feeder signal may include a third signal and a fifth signal;

[0074] The second feeder signal may include a fourth signal and a sixth signal;

[0075] The fifth signal may include an indication that the fifth signal is from the terminal;

[0076] The sixth signal may include an indication that the sixth signal is from the terminal;

[0077] When executed by one or more processors, the instructions may further cause the apparatus to perform at least one of the following:

[0078] combining the third signal and the fifth signal to obtain a first combined signal; and

[0079] The fourth signal and the sixth signal are combined to obtain a second combined signal.

[0080] The first combined signal may include a first feeder signal; and / or

[0081] The second combined signal may include a second feeder signal.

[0082] The first combined signal may be composed of the first feeder signal; and

[0083] The second combined signal may be composed of the second feeder signal.

[0084] When executed by one or more processors, the instructions may further cause the apparatus to perform at least one of the following:

[0085] monitoring whether the quality of the first feeder signal is better than a threshold, and

[0086] instructing the first satellite to switch reception of the first feeder signal to another antenna if the quality of the first feeder signal is not better than the threshold; and

[0087] monitoring whether the quality of the second feeder signal is better than a threshold, and

[0088] If the quality of the second feeder signal is not better than the threshold, the second satellite is instructed to switch reception of the second feeder signal to another antenna.

[0089] According to a fourth aspect of the present invention, there is provided a method comprising:

[0090] receiving a first signal by a first antenna;

[0091] receiving a second signal by a second antenna;

[0092] forwarding a feeder signal to a base station, wherein the feeder signal is based on the first signal and the second signal, wherein

[0093] The polarization angle of the second antenna is different from the polarization angle of the first antenna.

[0094] The feeder signal may include a first signal and a second signal.

[0095] The method may further include:

[0096] combining the first signal and the second signal into a single signal; wherein

[0097] The feeder signal may comprise this single signal.

[0098] The feeder signal may not include the first signal received by the first antenna; and / or

[0099] The feeder signal may not include the second signal received by the second antenna.

[0100] According to a fifth aspect of the present invention, there is provided a method, the method comprising:

[0101] receiving a first signal by a first antenna;

[0102] forwarding the first signal to a base station;

[0103] monitoring whether a command to switch to the second antenna is received from the base station;

[0104] If the command is received, prohibiting forwarding of the first signal;

[0105] receiving a second signal by a second antenna;

[0106] If the command is received, a second signal is forwarded to the base station, wherein

[0107] The polarization angle of the second antenna is different from the polarization angle of the first antenna.

[0108] According to a sixth aspect of the present invention, there is provided a method, the method comprising:

[0109] receiving a first feeder signal from a first satellite;

[0110] receiving a second feeder signal from a second satellite different from the first satellite;

[0111] The first combined signal and the second combined signal are combined by MIMO processing, wherein

[0112] The first feeder signal includes an indication that the first feeder signal is based on a third signal from the terminal;

[0113] the second feeder signal including an indication that the second feeder signal is based on a fourth signal from the terminal;

[0114] The first combined signal is based on the first feeder signal;

[0115] The second combined signal is based on the second feeder signal.

[0116] The first feeder signal may include a third signal and a fifth signal;

[0117] The second feeder signal may include a fourth signal and a sixth signal;

[0118] The fifth signal may include an indication that the fifth signal is from the terminal;

[0119] The sixth signal may include an indication that the sixth signal is from the terminal;

[0120] The method may include at least one of the following:

[0121] combining the third signal and the fifth signal to obtain a first combined signal; and

[0122] The fourth signal and the sixth signal are combined to obtain a second combined signal.

[0123] The first combined signal may include a first feeder signal; and / or

[0124] The second combined signal may include a second feeder signal.

[0125] The first combined signal may be composed of the first feeder signal; and

[0126] The second combined signal may be composed of the second feeder signal.

[0127] The method may further include at least one of the following:

[0128] monitoring whether the quality of the first feeder signal is better than a threshold, and

[0129] instructing the first satellite to switch reception of the first feeder signal to another antenna if the quality of the first feeder signal is not better than the threshold; and

[0130] monitoring whether the quality of the second feeder signal is better than a threshold, and

[0131] If the quality of the second feeder signal is not better than the threshold, the second satellite is instructed to switch reception of the second feeder signal to another antenna.

[0132] Each method of the fourth to sixth aspects may be a satellite communication method.

[0133] According to a seventh aspect of the present invention, there is provided a computer program product comprising a set of instructions, which, when executed on a device, is configured to cause the device to perform a method according to any one of the fourth to sixth aspects. The computer program product may be embodied as a computer-readable medium or directly loadable into a computer.

[0134] According to some embodiments of the present invention, at least one of the following advantages can be achieved:

[0135] • Performing multi-antenna processing in the base station where the individual antenna streams have high variable differential delays.

[0136] It should be understood that any of the above modifications may be applied individually or in combination to the corresponding aspects to which they refer, unless they are explicitly stated to exclude alternatives. BRIEF DESCRIPTION OF THE DRAWINGS

[0137] Other details, features, objects and advantages will become apparent from the following detailed description of preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which:

[0138] Figure 1 UL hybrid MIMO over multiple multi-antenna satellites according to an example embodiment of the present invention is shown;

[0139] Figure 2 Method 1 of UL hybrid MIMO over multiple multi-antenna satellites according to an example embodiment of the present invention is shown;

[0140] Figure 3 Method 2 of UL hybrid MIMO over multiple multi-antenna satellites according to an example embodiment of the present invention is shown;

[0141] Figure 4 Method 3 of UL hybrid MIMO over multiple multi-antenna satellites according to an example embodiment of the present invention is shown;

[0142] Figure 5 An apparatus according to an example embodiment of the present invention is shown;

[0143] Figure 6 A method according to an example embodiment of the present invention is shown;

[0144] Figure 7 An apparatus according to an example embodiment of the present invention is shown;

[0145] Figure 8 A method according to an example embodiment of the present invention is shown;

[0146] Figure 9 An apparatus according to an example embodiment of the present invention is shown;

[0147] Figure 10 A method according to an example embodiment of the present invention is shown; and

[0148] Figure 11 An apparatus according to an example embodiment of the invention is shown. DETAILED DESCRIPTION

[0149] Hereinafter, certain embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein, unless otherwise specified, the features of the embodiments may be freely combined with each other. However, it should be clearly understood that the description of certain embodiments is given by way of example only and is in no way intended to limit the invention to the disclosed details.

[0150] 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.

[0151] Some exemplary embodiments provide solutions for performing multi-antenna processing in base stations where individual antenna streams have high variable differential delays. More specifically, some exemplary embodiments of the present invention provide a hybrid MIMO solution: MIMO over multiple satellites, where each satellite is designed with multiple antennas per cell to achieve multi-antenna diversity. By applying multi-antenna diversity on each individual satellite and MIMO over multiple satellites, the system link budget can be improved. Hybrid MIMO differs from conventional MIMO in that it includes two spatial signal processing stages:

[0152] Phase 1: Each satellite has multiple antennas with different (usually orthogonal) polarization angles. The output of Phase 1 is a single signal combined from the satellite's multiple antennas. The benefits are that it can compensate for polarization loss and achieve multi-antenna diversity gain.

[0153] Phase 2: MIMO is applied on top of each satellite signal generated in Phase 1.

[0154] The benefit is to obtain MIMO gain.

[0155] Figure 1 Shown are multiple ( Figure 1 Block diagram of hybrid MIMO on three multi-antenna satellites. Figure 1 In the UE, there are multiple ( Figure 1 There are two) antennas with different polarization directions. Each satellite also has multiple ( Figure 1 Two antennas are used for each geographic cell. The number of antennas with different polarizations at the UE can be the same as or different from the number of antennas with different polarizations at each satellite. Different satellites can have the same number of antennas with different polarizations or different numbers of antennas. It is assumed that multiple satellites are visible above the geographic cell where the UE is located.

[0156] When a UE simultaneously transmits an RF signal into space via its two antennas, the RF signal is received by all antennas on all satellites. Each satellite transmits the RF signal received by its antennas to ground stations (including base stations (e.g., gNBs)) via feeder links. Note that for any given UE, its PRBs and TAs are configured and scheduled by only one corresponding satellite (called the primary satellite). The other satellites are listening satellites for the UE's signal. This configuration provides rich information for measures to enhance spatial processing performance.

[0157] Figures 2 to 4Further details of some solutions according to example embodiments of the present invention are provided, including a description of the corresponding gNB receiver processing. The description is given for signals from a single UE. If multiple UEs are present, the same description applies to each UE accordingly.

[0158] Phase 1 - Multi-antenna diversity approach by combining multiple antennas on a single satellite1( Figure 2 )

[0159] like Figure 2 As shown, antenna combining is performed at the base station (e.g., gNB): the gNB receiver first receives and processes multiple antenna streams for each satellite. The primary satellite antenna stream enters a delay buffer to synchronize with the listening satellite(s), and then enters the multi-antenna diversity combining processing unit.

[0160] According to some example embodiments of the present invention, the gNB schedules PRBs on the "primary satellite." On the other hand, the gNB does not schedule PRBs for the UE on the listening satellite(s). Therefore, the gNB processes antenna streams from the listening satellite(s).

[0161] Specifically, the gNB may process the antenna streams from each of the listening satellite(s) as follows:

[0162] 1. Receive antenna streams containing PRB RF samples for UEs that are not scheduled by the gNB on the listening satellite, but for which PRBs are scheduled by the gNB on the primary satellite.

[0163] 2. For each listening satellite: Estimate the TA of the UE to estimate the timing offset between the primary satellite and the corresponding listening satellite.

[0164] 3. Synchronize the timing of all antenna streams from the primary and listening satellites using their estimated TAs, and then combine all antenna data streams into a single antenna data stream. An example combining method is MRC (Maximum Ratio Combining), which combines all antennas using the corresponding SNR values as weights for each antenna's stream.

[0165] In some example embodiments, timing misalignment between the corresponding antennas of the primary satellite and one or more of the listening satellites can be additionally compensated. However, depending on the system design, timing misalignment between antennas of a single satellite can be skipped if all antenna sampling and sample data transmission misalignments have been controlled to be within the timing tolerance of the gNB physical layer processing. Timing misalignment of multiple antennas within the same satellite is similar to that of ground-based TN gNB multi-antenna systems, but the buffer size can be different because each antenna stream is sent from the satellite to the gNB via a feeder link and the DDC will perform buffering and heading timing alignment. Some conventional L1 processing units may only have a tolerance range of 100sns. Therefore, in some example embodiments of the present invention, the buffer size is increased to compensate for larger antenna timing misalignments.

[0166] In addition to the above processing, the gNB can optionally perform noise / interference filtering, channel estimation, channel compensation, SNR estimation, etc.

[0167] The listening satellite antenna stream performs the estimation and compensation process for the UE timing offset between the primary satellite and the listening satellite(s).

[0168] When a UE transmits an RF signal, all satellites viewing the UE will receive the RF signal, but different satellites will receive the RF signal at different times due to varying distances. Timing offset is measured for each UE and each satellite by the TA. Because the gNB schedules UEs only on the primary satellite, no UE scheduling information is available on the listening satellites. Therefore, existing systems cannot measure the TA on the listening satellites. Some exemplary embodiments of the present invention compensate for the TA of the listening satellites in the gNB, which is aware of the UE's scheduling via the primary satellite.

[0169] The antenna diversity combined signal (a "feeder signal") then enters the MIMO combining process. There are two options for performing multi-antenna diversity combining:

[0170] 1) Merge before L1 receiver.

[0171] 2) Merge inside the L1 receiver.

[0172] If combining is inside the L1 receiver (option 2), each antenna stream requires a separate buffer before input into the L1 receiver. If combining is performed before the input of the L1 receiver (option 1), multiple antenna streams only require 1 buffer per satellite.

[0173] Method 2( Figure 3 )

[0174] like Figure 3As shown, antenna diversity combining is performed on the satellite: that is, multiple antenna RF streams are combined into a "feeder signal" on the satellite. The advantages of this configuration are as follows: In space mobile systems, feeder link bandwidth is very limited. Multiple antennas consume multiple bandwidths on the feeder link. By performing antenna combining on the satellite (Phase 1 processing), only a single antenna bandwidth is used on the feeder link. This can save a significant amount of feeder link resources, which can be used, for example, to increase cell capacity.

[0175] Even for multiple antennas on the UL, the UE signal can be reflected from objects on the ground (such as buildings, etc.), and antenna diversity combining can also be performed at the satellite. The signal then goes to the satellite. However, the distance between the UE and multipath reflecting objects (such as buildings) is typically in the range of a few kilometers (or even shorter), but the distance between the UE and the satellite may be as high as 1500km. Therefore, the UE's multi-antenna signals received by the satellite have almost the same arrival angle, which means that the RF signals from the UE's multiple antennas can be directly combined. In the example of two antennas, the two antennas typically have orthogonal polarization angles. After combining, the polarization loss is significantly reduced. Combining multiple antennas on the satellite is a balance between performance and capacity.

[0176] That is, if antenna combining is performed on the gNB (e.g., at its soft bit level):

[0177] Advantages: Each antenna can perform noise / interference filtering, channel estimation, channel compensation, antenna combining by SNR weighting, etc. This will improve performance.

[0178] Disadvantage: Each antenna will consume feeder link bandwidth separately

[0179] If antenna combining is performed on a satellite:

[0180] Advantages: All antennas consume only a single antenna bandwidth on the feeder link.

[0181] Disadvantages: No signal processing on satellite. Uses equal weighting (no SNR weighting, etc.)

[0182] Antennas are combined at the RF samples. This will degrade performance compared to combining at the gNB (e.g., at its soft bit level).

[0183] Each satellite then transmits the antenna diversity combined signal (a "feeder signal") to the base station where the MIMO combining is performed.

[0184] Method 3( Figure 4 )

[0185] like Figure 4As shown, antenna switching can be performed on the satellite: each satellite can be configured with multiple antennas for each cell, but the antennas operate in time-division multiplexing mode. RF antenna switching is implemented on the satellite. Only one antenna is active at a time. The antenna selection process is as follows:

[0186] The gNB monitors the gNB-UE link performance in real time through corresponding measurements of signal quality (e.g., via CQI reports in the downlink or via DMRS / SRS in the uplink).

[0187] If the quality is below a threshold, the gNB instructs the satellite to switch from the currently active antenna to another antenna. This includes switching satellite antennas and / or switching UE antennas to mitigate polarization losses for each UE; for example, the gNB may instruct a switch if the current link performance drops below a predefined threshold.

[0188] Select the antenna with the highest performance measurement (based on previous measurements of link performance)

[0189] In this case, the "feeder signal" is the signal from the selected antenna. Note that each satellite antenna needs to serve all UEs in the cell. Therefore, switching the UE antenna to minimize polarization loss can be specific to a given UE.

[0190] Phase 2 – UL MIMO over multiple satellites

[0191] The output of stage 1 is a combined message for each satellite. All receptions from a single UE are also timed and synchronized at the stage 1 output. Therefore, the stage 1 outputs for all satellites are sent to the MIMO processing unit. The MIMO processing unit can support at least one of the following: Layer 1 (LTE TM2 transmit diversity) to increase the SNR and, therefore, the MCS table data rate; and Layer 2 (LTE TM4 closed-loop spatial multiplexing) to increase the data rate.

[0192] Figure 5 An apparatus according to an exemplary embodiment of the present invention is shown. The apparatus may be a satellite or an element thereof. Figure 6 A method according to an exemplary embodiment of the present invention is shown. Figure 5 The device can perform Figure 6 method, but not limited to this method. Figure 6 The method can be Figure 5 The present invention is performed by a device, but is not limited to being performed by the device.

[0193] The apparatus includes a first antenna 101, a second antenna 102, a first receiving component 110, a second receiving component 120, and a forwarding component 130. The first receiving component 110, the second receiving component 120, and the forwarding component 130 may be a first receiving component, a second receiving component, and a forwarding component, respectively. The first receiving component 110, the second receiving component 120, and the forwarding component 130 may be a first receiver, a second receiver, and a forwarder, respectively. The first receiving component 110, the second receiving component 120, and the forwarding component 130 may be a first receiving processor, a second receiving processor, and a forwarding processor, respectively.

[0194] The polarization angle of the second antenna 102 is different from the polarization angle of the first antenna 101 .

[0195] The first receiving component 110 receives a first signal via a first antenna (S110). The second receiving component 120 receives a second signal via a second antenna (S120). Both the first signal and the second signal may originate from a terminal. The forwarding component 130 forwards a feeder signal to a base station (S130). The feeder signal is based on the first signal from S110 and the second signal from S120. For example, the feeder signal may include the first signal and the second signal, or the feeder signal may be generated by combining the first signal and the second signal.

[0196] Figure 7 An apparatus according to an exemplary embodiment of the present invention is shown. The apparatus may be a satellite or an element thereof. Figure 8 A method according to an exemplary embodiment of the present invention is shown. Figure 7 The device can perform Figure 8 method, but not limited to this method. Figure 8 The method can be Figure 7 The present invention is performed by a device, but is not limited to being performed by the device.

[0197] The apparatus includes a first antenna 201, a second antenna 202, a first receiving component 210, a first forwarding component 220, a monitoring component 230, a disabling component 240, a second receiving component 250, and a second forwarding component 260. The first receiving component 210, the first forwarding component 220, the monitoring component 230, the disabling component 240, the second receiving component 250, and the second forwarding component 260 may be a first receiving component, a first forwarding component, a monitoring component, a disabling component, a second receiving component, and a second forwarding component, respectively. The first receiving component 210, the first forwarding component 220, the monitoring component 230, the disabling component 240, the second receiving component 250, and the second forwarding component 260 may be a first receiver, a first forwarder, a monitor, a disabling component, a second receiver, and a second forwarder, respectively. The first component for receiving 210, the first component for forwarding 220, the component for monitoring 230, the component for disabling 240, the second component for receiving 250 and the second component for forwarding 260 can be a first receiving processor, a first forwarding processor, a monitoring processor, a disabling processor, a second receiving processor and a second forwarding processor, respectively.

[0198] The polarization angle of the second antenna 202 is different from the polarization angle of the first antenna 201 .

[0199] The first receiving component 210 receives a first signal via a first antenna (S210). The first forwarding component 220 forwards the first signal to a base station (S220). At this time, forwarding of signals received by antennas other than the first antenna may be prohibited.

[0200] The means 230 for monitoring monitors whether a command to switch to the second antenna is received from the base station (S230).

[0201] The second receiving component 250 receives the second signal via the second antenna (S250). S210 and S250 may be performed in any order. They may be performed in whole or in part in parallel.

[0202] If the command is received (S230=Yes), then:

[0203] The prohibiting means 240 prohibits forwarding of the first signal (S240); and

[0204] The second component 260 for forwarding forwards the second signal to the base station (S260).

[0205] S240 and S260 can be executed in any order. They can be executed in whole or in part in parallel. In some example embodiments, Figure 8As shown, the receiving (S250) performed by the second receiving component 250 can be performed only when the command is received (S230=Yes). However, in other example embodiments, the receiving (S250) performed by the second receiving component 250 can be performed regardless of whether the command is received (S230=Yes or No).

[0206] Figure 9 An apparatus according to an example embodiment of the present invention is shown. The apparatus may be a base station (such as a gNB or eNB) or an element thereof. Figure 10 A method according to an exemplary embodiment of the present invention is shown. Figure 9 The device can perform Figure 10 method, but not limited to this method. Figure 10 The method can be Figure 9 The present invention is performed by a device, but is not limited to being performed by the device.

[0207] The apparatus includes a first receiving component 310, a second receiving component 320, and a merging component 330. The first receiving component 310, the second receiving component 320, and the merging component 330 may be a first receiving component, a second receiving component, and a merging component, respectively. The first receiving component 310, the second receiving component 320, and the merging component 330 may be a first receiver, a second receiver, and a merging processor, respectively. The first receiving component 310, the second receiving component 320, and the merging component 330 may be a first receiving processor, a second receiving processor, and a merging processor, respectively.

[0208] The first receiving component 310 receives a first feeder signal from a first satellite (S310). The first feeder signal includes an indication that the first feeder signal is based on a third signal from a terminal. The second receiving component 320 receives a second feeder signal from a second satellite (S320). The second feeder signal includes an indication that the second signal is based on a fourth signal from a terminal (i.e., from the same terminal as the first signal). The second satellite is different from the first satellite.

[0209] The combining component 330 combines the first combined signal and the second combined signal through MIMO processing (S330). The first combined signal is based on the first feeder signal. The second combined signal is based on the second feeder signal. For example, if the corresponding feeder signal is an antenna diversity combined signal, the corresponding combined signal can be the same as the corresponding feeder signal. As another example, if the corresponding feeder signal includes two signals from two antennas of the corresponding satellite, the corresponding combined signal can be obtained by antenna diversity combining of the two signals.

[0210] Figure 11The apparatus according to an embodiment of the present invention is shown. The apparatus comprises at least one processor 810, at least one memory 820 including computer program code, the at least one processor 810 being arranged to cause the apparatus to perform at least according to the at least one memory 820 and the computer program code together. Figure 6 、 Figure 8 and Figure 10 At least one of and the related described methods.

[0211] Some example embodiments of the present invention are described for NTNs. However, some example embodiments may be applied to other situations where individual antenna streams have highly variable differential delays, for example where the base station is mounted on a fast vehicle.

[0212] Some example embodiments are described with respect to 5G networks. However, the present invention is not limited to 5G. It can also be used in other mobile communication networks using beamforming, for example, in next-generation 3GPP networks such as 4G, 6G, or 7G. It can also be used in non-3GPP (mobile or fixed) communication networks with a transparent payload architecture.

[0213] A base station (e.g., a gNB) can be decomposed into a CU, one or more DUs, and a corresponding RU for each DU. However, the present invention is not limited to decomposed base stations. For example, the RU and DU can be aggregated into a single device, or even the CU, (multiple) DUs, and (multiple) RUs can be aggregated into a single device.

[0214] A piece of information can be transmitted from one entity to another in one or more messages. Each of these messages can include additional (different) information.

[0215] 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.

[0216] Unless otherwise stated or clear from the context, a 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 description can be deployed in the cloud.

[0217] From the above description, it should be clear that exemplary embodiments of the present invention provide, for example, a base station (such as a gNB or eNB) or a component thereof, an apparatus embodying the same, a method for controlling and / or operating the same, and (multiple) computer programs for controlling and / or operating the same, as well as a medium carrying (multiple) such computer programs and forming (multiple) computer program products. From the above description, it should be clear that exemplary embodiments of the present invention provide, for example, a satellite or a component thereof, an apparatus embodying the same, a method for controlling and / or operating the same, and (multiple) computer programs for controlling and / or operating the same, as well as a medium carrying (multiple) such computer programs and forming (multiple) computer program products.

[0218] 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 may be embodied in the cloud.

[0219] It should be understood that the above description 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 that various modifications can be made without departing from the scope of the present invention as defined by the appended claims.

[0220] The phrase "at least one of A and B" includes option A only, option B only, and options A and B both. Unless otherwise specified, the terms "first X" and "second X" include the options "first" and "second X" are the same and "first X" and "second X" are different. The term "comprising y" means "comprising y and may include other items." The term "consisting of z" means "including z but excluding anything else."

Claims

1. A device comprising: The satellite's first antenna; a second antenna for the satellite, wherein a polarization angle of the second antenna is different from a polarization angle of the first antenna; one or more processors; as well as a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: receiving a first signal by the first antenna; receiving a second signal by the second antenna, wherein the first signal and the second signal have substantially the same angle of arrival; directly merging the first signal and the second signal into a single signal; forwarding a feeder signal from the satellite to a base station, wherein the feeder signal is based on the first signal and the second signal; in The feeder signal includes the single signal; The feeder signal does not include the first signal received by the first antenna; and The feeder signal does not include the second signal received by the second antenna.

2. A device comprising: First antenna; a second antenna, wherein a polarization angle of the second antenna is different from a polarization angle of the first antenna; one or more processors; as well as a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform: receiving a first signal from a user equipment by the first antenna; forwarding the first signal to a base station; monitoring whether a command to switch to the second antenna is received from the base station; If the command is received, prohibiting the forwarding of the first signal; receiving a second signal from the user equipment by the second antenna; If the command is received, the second signal is forwarded to the base station.

3. A device 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 a first feeder signal from a first satellite; receiving a second feeder signal from a second satellite different from the first satellite; combining the first combined signal and the second combined signal by MIMO processing, monitoring whether the quality of the first feeder signal is better than a threshold, and If the quality of the first feeder signal is not better than the threshold, instructing the first satellite to switch reception of the first feeder signal to another antenna; and monitoring whether the quality of the second feeder signal is better than the threshold, and If the quality of the second feeder signal is not better than the threshold, instructing the second satellite to switch reception of the second feeder signal to another antenna; The first feeder signal includes an indication that the first feeder signal is based on a third signal from a terminal; The second feeder signal includes an indication that the second feeder signal is based on a fourth signal from the terminal; The first combined signal includes the first feeder signal; The second combined signal includes the second feeder signal.

4. The device according to claim 3, wherein The first feeder signal includes the third signal and the fifth signal; The second feeder signal includes the fourth signal and the sixth signal; The fifth signal includes an indication that the fifth signal is from the terminal; The sixth signal includes an indication that the sixth signal is from the terminal; The instructions, when executed by the one or more processors, further cause the apparatus to perform at least one of the following: combining the third signal and the fifth signal to obtain the first combined signal; and The fourth signal and the sixth signal are combined to obtain the second combined signal.

5. The device according to any one of claims 3 and 4, wherein at least one of the following: The first combined signal is composed of the first feeder signal; and The second combined signal is composed of the second feeder signal.

6. A method comprising: Receiving a first signal by a first antenna of a satellite; receiving a second signal by a second antenna of the satellite, wherein the first signal and the second signal have substantially the same angle of arrival; directly merging the first signal and the second signal into a single signal; A feeder signal is forwarded from the satellite to a base station, wherein the feeder signal is based on the first signal and the second signal, wherein The polarization angle of the second antenna is different from the polarization angle of the first antenna; as well as The feeder signal includes the single signal; The feeder signal does not include the first signal received by the first antenna; and The feeder signal does not include the second signal received by the second antenna.

7. A method comprising: receiving a first signal from a user equipment by a first antenna; forwarding the first signal to a base station; monitoring whether a command to switch to a second antenna is received from the base station; If the command is received, prohibiting the forwarding of the first signal; receiving a second signal from the user equipment by the second antenna; If the command is received, the second signal is forwarded to the base station, wherein The polarization angle of the second antenna is different from the polarization angle of the first antenna.

8. A method comprising: receiving a first feeder signal from a first satellite; receiving a second feeder signal from a second satellite different from the first satellite; The first combined signal and the second combined signal are combined by MIMO processing, wherein The first feeder signal includes an indication that the first feeder signal is based on a third signal from a terminal; The second feeder signal includes an indication that the second feeder signal is based on a fourth signal from the terminal; monitoring whether the quality of the first feeder signal is better than a threshold, and If the quality of the first feeder signal is not better than the threshold, instructing the first satellite to switch reception of the first feeder signal to another antenna; and monitoring whether the quality of the second feeder signal is better than the threshold, and if the quality of the second feeder signal is not better than the threshold, instructing the second satellite to switch reception of the second feeder signal to another antenna; The first combined signal includes the first feeder signal; The second combined signal includes the second feeder signal.

9. The method according to claim 8, wherein The first feeder signal includes the third signal and the fifth signal; The second feeder signal includes the fourth signal and the sixth signal; The fifth signal includes an indication that the fifth signal is from the terminal; The sixth signal includes an indication that the sixth signal is from the terminal; The method comprises at least one of the following: combining the third signal and the fifth signal to obtain the first combined signal; and The fourth signal and the sixth signal are combined to obtain the second combined signal.

10. The method according to any one of claims 8 and 9, wherein at least one of the following: The first combined signal is composed of the first feeder signal; and The second combined signal is composed of the second feeder signal.

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