SPECTRUM SHARING IN NTN-TN COORDINATION

Solutions pertaining to spectrum sharing in coordination between a non-terrestrial network (NTN) and a terrestrial network (TN) are proposed. An apparatus implemented in a UE measures a signal strength of each of one or more TN cells and one or more NTN cells. The apparatus reports a result of the measuring to a TN. The apparatus also receives an indication from the TN configuring and activating a bandwidth part (BWP) that separates transmission by a base station of the TN from NTN downlink (DL) transmissions.

TECHNICAL FIELD

The present disclosure is generally related to mobile communications and, more particularly, to spectrum sharing in coordination between a non-terrestrial network (NTN) and a terrestrial network (TN).

BACKGROUND

In wireless communications such as mobile communications according to the 3rd Generation Partnership Project (3GPP) specifications, spectrum sharing refers to two systems sharing the same carriers. For instance, in the context of TN-NTN spectrum sharing, the TN can reuse the same spectrum used by the NTN. This can free up a lot of spectrum for TN reuse. One challenge, however, is TN-to-NTN interference. Additionally, it is noteworthy that NTN satellite power on the ground tends to be relatively small. That is, NTN (e.g., satellite) power reaching a TN user equipment (UE) is typically significantly low (e.g., close to thermal noise floor) for most UEs that are within TN coverage. NTN UEs are expected to be outside of TN coverage, and thus the level of interference on TN network from NTN UEs tends to be low. On the other hand, one main challenge is TN interference on uplink (UL) transmissions from a NTN UE to a satellite. As a satellite beam can cover large areas, aggregate TN interference on NTN UL transmissions can be very high. Moreover, due to geographical separation, TN interference on downlink (DL) transmissions to NTN UEs tends to be less problematic.

For standard pairing, the NTN and TN systems would share the same resources for DL transmissions and the same resources for UL transmissions. On the DL, if the TN and NTN share the same bandwidth, the mobility management could handle the interference. Signal quality of the TN (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-noise ratio (SNR) and the like) should be much better than signal quality of the NTN in most of the cases when the coverage of the TN and the coverage of the NTN overlap. The UE should stay on the TN in most of the cases even if the NTN is causing interference on the TN. Therefore, there is a need for a solution for spectrum sharing in NTN-TN coordination to address aforementioned issues.

SUMMARY

An objective of the present disclosure is to propose solutions or schemes that address the aforementioned issues. More specifically, various schemes proposed in the present disclosure pertain to spectrum sharing in NTN-TN coordination.

In one aspect, a method may involve a UE measuring a signal strength of each of one or more TN cells and one or more NTN cells. The method may also involve the UE reporting a result of the measuring to a TN.

In one aspect, a method may involve a UE receiving an indication from the TN configuring and activating a bandwidth part (BWP) that separates transmission by a base station of the TN from NTN DL transmissions.

In yet another aspect, an apparatus may include a transceiver and a processor coupled to the transceiver. The transceiver may be configured to communicate wirelessly. The processor may measure, via the transceiver, a signal strength of each of one or more TN cells and one or more NTN cells. The processor may also report, via the transceiver, a result of the measuring to a TN.

In still another aspect, an apparatus may include a transceiver and a processor coupled to the transceiver. The transceiver may be configured to communicate wirelessly. The processor may receive, via the transceiver, an indication from the TN configuring and activating a BWP that separates transmission by a base station of the TN from NTN DL transmissions.

It is noteworthy that, although description provided herein may be in the context of certain radio access technologies, networks and network topologies such as TN and NTN, the proposed concepts, schemes and any variation(s)/derivative(s) thereof may be implemented in, for and by other types of radio access technologies, networks and network topologies such as, for example and without limitation, Long-Term Evolution (LTE), LTE-Advanced, LTE-Advanced Pro, 5th Generation (5G), New Radio (NR), Internet-of-Things (IoT), Narrow Band Internet of Things (NB-IoT), Industrial Internet of Things (IIoT). Thus, the scope of the present disclosure is not limited to the examples described herein.

DETAILED DESCRIPTION OF PREFERRED IMPLEMENTATIONS

Overview

FIG.1illustrates an example scenario100under a proposed scheme with respect to TN-NTN mobility management in accordance with the present disclosure. It is noteworthy that there may be cases in which the signal quality experienced by a UE in a TN is not good, or otherwise less than desirable, and the UE should switch to the NTN. For instance, one possible case is at the very edge of an area under TN coverage. Accordingly, a criterion related to signal quality (e.g., RSRP, RSRQ, SNR and/or channel fading) may be used to determine mobility switching from the TN to an NTN, although it may still be preferable for the UE to stay on the TN as much as possible.

Under the proposed scheme, TN versus NTN-based mobility criterion may be implemented to avoid unnecessary switch from the TN to the NTN due to satellite mobility. Specifically, the UE may implement a mobility criterion related to signal quality (e.g., based on RSRP, RSRQ, SNR, UE location and the like) in choosing between TN and NTN cells. Moreover, different thresholds may be applied to TN and NTN cells to ensure that TN cells are prioritized over NTN cells. This may be achieved by introducing offsets to boost the rank of one or more TN cells, or to reduce the rank of one or more NTN cells, or to ensure that measurement events are only triggered in case a signal strength of NTN cell(s) is significantly above the TN cell(s). For instance, this technique may be implemented through measurement events specific for NTN/TN.

Accordingly, the UE may need to know certain information about the NTN cells (e.g., via new signaling from the TN and/or NTN). The new signaling may be included in the broadcast information of NTN cells being measured (e.g., master information block (MIB)), which may take the form of NTN or TN characteristic in the system information block (SIB). Alternatively, the new signaling may be in the form of specific information about the NTN cells to be measured. For instance, the measurement object may include information indicating that the cells in the measurement object are NTN cells. Moreover, NTN long-term ephemeris (e.g., cell layout, coverage time, and the like) may be used by the UE in addition to a TN neighbor list.

Under the proposed scheme, when reporting one or more measured NTN cells to a TN serving cell, the UE may indicate that the cell(s) measured is/are NTN cell(s). Similarly, when reporting one or more measured TN cells to an NTN serving cell, the UE may indicate that the cell(s) measured is/are TN cell(s). New signaling may be included as part of the measurement report being sent by the UE to the serving cell, whether a TN serving cell or an NTN serving cell.

FIG.2illustrates an example scenario200under a proposed scheme with respect to BWP switching in accordance with the present disclosure. It is noteworthy that, on the UL, all TN UEs in a TN cell may cause interference on an NTN, especially when there are a very large number of UEs (e.g., potentially thousands or more) at a given time. On the other hand, interference caused by NTN UEs on TN UEs tends to be much less of a problem, especially since the number of NTN UEs tends to be limited and generally not in cell coverage. That is, the level of signal from an NTN UE reaching a base station (BS) of a TN tends to be very low. Under the proposed scheme, several approaches may be undertaken to reduce the TN-to-NTN interference. For instance, a very strict frequency domain separation for a Low-Earth-orbit (LEO) satellite. Additionally, a BWP mechanism may be re-used. Moreover, certain information may be included in broadcast or group common BWP switching, which may be radio resource control (RRC) or downlink control information (DCI) based, timer based, and/or location based.

Under the proposed scheme, group common BWP switching may be implemented using a group common DCI. This group common DCI may be monitored in a common search space. Alternatively, or additionally, group common BWP switching may be implemented using RRC reconfiguration to lower overhead. Alternatively, a dedicated SIB information broadcast may be utilized. Alternatively, or additionally, a time reference may be specified to trigger a timer-based BWP switching. For instance, the timer-based BWP switching may be linked to satellite ephemeris or other satellite availability information. Alternatively, or additionally, a location-based BWP switching may involve a UE-initiated BWP switching based on a location of the UE, similar to consistent listen-before-talk (LBT) failure detection in New Radio unlicensed spectrum (NR-U).

For TN DL transmissions interfering with NTN DL transmissions on a forward link, there may be TN and NTN measurements and reports by an NTN UE to a TN network, and then BWP configuration and activation may be utilized to separate transmissions of a TN base station (e.g., gNB) from NTN DL transmissions in the NTN UE. Under the proposed scheme, broadcast on a SIB of TN or NTN types may be utilized to identify measurement events for TN or NTN. Additionally, timer-based mechanisms and UE group conditional handover (CHO) for beam switching of TN UEs on DL may be done with long-term knowledge of satellite ephemeris. In such cases, the UE may trigger measurements and reports, and the UE may autonomously activate a configured BWP. The TN network may indicate a UE group CHO command in DCI. The long-term ephemeris may include information on the number of beams per NTN cell and mapping to synchronization signal blocks (SSBs) as well as a configuration of an initial BWP #0. Under the proposed scheme, SSB measurements in the initial BWP #0of TN or NTN cell by the UE may be sufficient. It does not need to be very accurate and this may limit the amount of signaling as there is no need, and this may indicate other BWP #X configurations including channel state information (CSI) reference signal (RS) for NTN cell(s). Moreover, the UE may report its location and the network may determine to indicate to the UE to switch BWPs or refrain from scheduling to the UE until the satellite flies by. The network may have access to the long-term satellite ephemeris.

For TN UL transmissions interfering with NTN devices on a return link, geographical separate between TN and NTN cells may not be possible. The network with knowledge of the long-term satellite ephemeris may configure BWPs to preserve a guard band for mitigation of out-of-band (OOB) emissions. The granularity of the specified BWP configurations for TN may be sufficient to allow the gNB to activate or deactivate configured BWPs based on the given beams in an NTN cell regarding which the satellite is flying by. Additionally, timer-based activation and deactivation and UE group CHO for beam switching of TN UEs on UL transmissions may be mechanisms used by the network. Under the proposed scheme, the DL and UL beam switching of TN UEs may be paired (e.g., done at the same time to reduce signaling overhead). Moreover, TN UEs close to the gNB of the TN with UL transmission power control by UL Power Control (UPC) (and hence relatively smaller) may be configured a BWP with a smaller guard band. These UEs close to the gNB may increase their power via Transmit Power Control (TPC) on DCI in case that NTN UL transmissions cause significant interference. Furthermore, it may be possible to have no guard band at all and even share the same band between TN and NTN for these UEs.

Under a proposed scheme in accordance with the present disclosure with respect to OOB emission reduction capability, a TN cell may adapt a BWP based on the satellite in view. Advantageously, the channel bandwidth (BW) and/or OOB emission may be already configured per BWP. However, spectrum emission mask may need to be improved (e.g., −10 dBm to −13 dBm per 1 MHz only). In case that 10,000 TN UEs are interfering NTN with −10 dBm, the total interference power may be approximately 30 dBm. For an NTN UE at 23 dBm, the signal-to-interference ratio (SIR) may be −7 dB. Thus, under the proposed scheme, each UE may be configured with a UE capability to support TN-NTN spectrum sharing with tighter OOB emissions (e.g., with an OOB emission mask no greater than a predefined threshold such as an OOB emission mask with no TN-NTN spectrum sharing).

Illustrative Implementations

FIG.3illustrates an example communication system300having an example apparatus310and an example apparatus320in accordance with an implementation of the present disclosure. Each of apparatus310and apparatus320may perform various functions to implement schemes, techniques, processes and methods described herein pertaining to spectrum sharing in NTN-TN coordination, including scenarios/schemes described above as well as process(es) described below.

Apparatus310may be a part of an electronic apparatus, which may be a UE such as a portable or mobile apparatus, a wearable apparatus, a wireless communication apparatus or a computing apparatus. For instance, apparatus310may be implemented in a smartphone, a smartwatch, a personal digital assistant, a digital camera, or a computing equipment such as a tablet computer, a laptop computer or a notebook computer. Apparatus310may also be a part of a machine type apparatus, which may be an IoT, NB-IoT, IIoT or NTN apparatus such as an immobile or a stationary apparatus, a home apparatus, a wire communication apparatus or a computing apparatus. For instance, apparatus310may be implemented in a smart thermostat, a smart fridge, a smart door lock, a wireless speaker or a home control center. Alternatively, apparatus310may be implemented in the form of one or more integrated-circuit (IC) chips such as, for example and without limitation, one or more single-core processors, one or more multi-core processors, one or more reduced-instruction set computing (RISC) processors, or one or more complex-instruction-set-computing (CISC) processors. Apparatus310may include at least some of those components shown inFIG.3such as a processor312, for example. Apparatus310may further include one or more other components not pertinent to the proposed scheme of the present disclosure (e.g., internal power supply, display device and/or user interface device), and, thus, such component(s) of apparatus310are neither shown inFIG.3nor described below in the interest of simplicity and brevity.

Apparatus320may be a part of an electronic apparatus/station, which may be a network node such as a base station, a small cell, a router, a gateway or a satellite. For instance, apparatus320may be implemented in an eNodeB in an LTE, in a gNB in a 5G, NR, IoT, NB-IoT, IIoT, or in a satellite in an NTN network. Alternatively, apparatus320may be implemented in the form of one or more IC chips such as, for example and without limitation, one or more single-core processors, one or more multi-core processors, or one or more RISC or CISC processors. Apparatus320may include at least some of those components shown inFIG.3such as a processor322, for example. Apparatus320may further include one or more other components not pertinent to the proposed scheme of the present disclosure (e.g., internal power supply, display device and/or user interface device), and, thus, such component(s) of apparatus320are neither shown inFIG.3nor described below in the interest of simplicity and brevity.

In some implementations, apparatus310may also include a transceiver316coupled to processor312and capable of wirelessly transmitting and receiving data. In some implementations, apparatus310may further include a memory314coupled to processor312and capable of being accessed by processor312and storing data therein. In some implementations, apparatus320may also include a transceiver326coupled to processor322and capable of wirelessly transmitting and receiving data. In some implementations, apparatus320may further include a memory324coupled to processor322and capable of being accessed by processor322and storing data therein. Accordingly, apparatus310and apparatus320may wirelessly communicate with each other via transceiver316and transceiver326, respectively.

Each of apparatus310and apparatus320may be a communication entity capable of communicating with each other using various proposed schemes in accordance with the present disclosure. To aid better understanding, the following description of the operations, functionalities and capabilities of each of apparatus310and apparatus320is provided in the context of a mobile communication environment in which apparatus310is implemented in or as a communication apparatus or a UE (e.g., NTN UE) and apparatus320is implemented in or as a network node or base station (e.g., NT network node such as a satellite) of a communication network (e.g., NTN). It is also noteworthy that, although the example implementations described below are provided in the context of mobile communications, the same may be implemented in other types of networks.

Under some proposed schemes pertaining to spectrum sharing in NTN-TN coordination in accordance with the present disclosure, with apparatus310implemented in or as an NTN UE and apparatus320implemented in or as a base station (e.g., gNB) of a TN or a satellite of an NTN, processor312may measure, via transceiver316, a signal strength of each of one or more TN cells and one or more NTN cells. Additionally, processor312may report, via transceiver316, a result of the measuring to a TN (e.g., via apparatus320as a base station, such as a gNB, of the TN).

In some implementations, in measuring, processor312may perform an SSB measurement in an initial BWP of a cell among the one or more TN cells and the one or more NTN cells. In some implementations, the SSB measurement may include an SSB measurement on the one or more NTN cells based on a long-term ephemeris. In some implementations, the long-term ephemeris may include a number of beams per NTN cell, mapping to SSBs, and a configuration of the initial BWP.

In some implementations, processor312may perform one or more additional operations. For instance, processor312may receive, via transceiver316, an SIB from apparatus320indicating whether a cell measured by the UE is of the TN or the NTN to identify measurement events for the TN or the NTN. Additionally, processor312may receive, via transceiver316, a higher-layer signaling (e.g., RRC signaling) that configures a measurement object with respect to the one or more TN cells and the one or more NTN cells.

Under some proposed schemes pertaining to spectrum sharing in NTN-TN coordination in accordance with the present disclosure, with apparatus310implemented in or as an NTN UE and apparatus320implemented in or as a base station (e.g., gNB) of a TN or a satellite of an NTN, processor312may receive, via transceiver316, an indication from the TN configuring and activating a BWP that separates transmission by apparatus320of the TN from NTN DL transmissions.

In some implementations, the indication may include a DCI indication.

In some implementations, the UE may be configured with a capability of supporting TN-NTN spectrum sharing with an00B emission mask no greater than a threshold.

In some implementations, processor312may perform one or more additional operations. For instance, processor312may receive, via transceiver316, a DCI signaling that indicates UE group common BWP switching. Additionally, processor312may receive, via transceiver316, a higher-layer signaling (e.g., RRC signaling) that configures UE group common BWP switching. Additionally, processor312may receive, via transceiver316, a configuration (e.g., from apparatus320) that configures a timer used in BWP switching. Additionally, processor312may receive, via transceiver316, a configuration (e.g., from apparatus320) that configures location-based BWP switching.

Illustrative Processes

FIG.4illustrates an example process400in accordance with an implementation of the present disclosure. Process400may be an example implementation of schemes described above whether partially or completely, with respect to spectrum sharing in NTN-TN coordination in accordance with the present disclosure. Process400may represent an aspect of implementation of features of apparatus310and/or apparatus320. Process400may include one or more operations, actions, or functions as illustrated by blocks410and420. Although illustrated as discrete blocks, various blocks of process400may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Moreover, the blocks of process400may executed in the order shown inFIG.4or, alternatively, in a different order. Process400may be implemented by apparatus310or any suitable UE or machine type devices. Solely for illustrative purposes and without limitation, process400is described below in the context of apparatus310implemented in or as an NTN UE and apparatus320implemented in or as a base station (e.g., gNB) of a TN or a satellite of an NTN. Process400may begin at block410.

At410, process400may involve processor312of apparatus310as a UE measuring, via transceiver316, a signal strength of each of one or more TN cells and one or more NTN cells. Process400may proceed from410to420.

At420, process400may involve processor312reporting, via transceiver316, a result of the measuring to a TN (e.g., via apparatus320as a base station, such as a gNB, of the TN).

In some implementations, in measuring, process400may involve processor312performing an SSB measurement in an initial BWP of a cell among the one or more TN cells and the one or more NTN cells. In some implementations, the SSB measurement may include an SSB measurement on the one or more NTN cells based on a long-term ephemeris. In some implementations, the long-term ephemeris may include a number of beams per NTN cell, mapping to SSBs, and a configuration of the initial BWP.

In some implementations, process400may involve processor312performing one or more additional operations. For instance, process400may involve processor312receiving, via transceiver316, an SIB from apparatus320indicating whether a cell measured by the UE is of the TN or the NTN to identify measurement events for the TN or the NTN. Additionally, process400may involve processor312receiving, via transceiver316, a higher-layer signaling (e.g., RRC signaling from apparatus320) that configures a measurement object with respect to the one or more TN cells and the one or more NTN cells.

FIG.5illustrates an example process500in accordance with an implementation of the present disclosure. Process500may be an example implementation of schemes described above whether partially or completely, with respect to spectrum sharing in NTN-TN coordination in accordance with the present disclosure. For instance, process500may be a continuation of process400in that process500may be performed in conjunction with and/or subsequent to process400. Process500may represent an aspect of implementation of features of apparatus310and/or apparatus320. Process500may include one or more operations, actions, or functions as illustrated by block510. Although illustrated as discrete blocks, various blocks of process500may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Moreover, the blocks of process500may executed in the order shown inFIG.5or, alternatively, in a different order. Process500may be implemented by apparatus310or any suitable UE or machine type devices. Solely for illustrative purposes and without limitation, process500is described below in the context of apparatus310implemented in or as an NTN UE and apparatus320implemented in or as a base station (e.g., gNB) of a TN or a satellite of an NTN. Process500may begin at block510.

At510, process500may involve processor312of apparatus310as a UE receiving, via transceiver316, an indication from a network (e.g., via apparatus320as a base station, such as a gNB, of the TN) configuring and activating a BWP that separates transmission by apparatus320of the TN from NTN DL transmissions.

In some implementations, the indication may include a DCI indication.

In some implementations, the UE may be configured with a capability of supporting TN-NTN spectrum sharing with an00B emission mask no greater than a threshold.

In some implementations, process400may involve processor312performing one or more additional operations. For instance, process400may involve processor312receiving, via transceiver316, a DCI signaling (e.g., from apparatus320) that indicates UE group common BWP switching. Additionally, process400may involve processor312receiving, via transceiver316, a higher-layer signaling (e.g., RRC signaling from apparatus320) that configures UE group common BWP switching. Additionally, process400may involve processor312receiving, via transceiver316, a configuration (e.g., from apparatus320) that configures a timer used in BWP switching. Additionally, process400may involve processor312receiving, via transceiver316, a configuration (e.g., from apparatus320) that configures location-based BWP switching.

ADDITIONAL NOTES