Patent Description:
The current disclosure relates to determining a reference resource.

The next generation mobile wireless communication system (<NUM>) or new radio (NR), will support a diverse set of use cases and a diverse set of deployment scenarios. The later includes deployment at both low frequencies (below <NUM>) and very high frequencies (up to <NUM>'s of GHz).

Like in LTE, NR uses CP-OFDM (Cyclic Prefix Orthogonal Frequency Division Multiplexing) in the downlink (i.e., from a network node, gNB, eNB, or base station, to a user equipment or UE) and both CP-OFDM and DFT-spread OFDM (DFT-S-OFDM) in the uplink (i.e., from UE to gNB). In the time domain, NR downlink and uplink are organized into equally-sized subframes of <NUM> each. A subframe is further divided into multiple slots of equal duration.

The slot length depends on subcarrier spacing. For subcarrier spacing of Δf = <NUM>, there is only one slot per subframe and each slot consists of <NUM> OFDM symbols.

Data scheduling in NR can be in slot basis as in LTE, an example is shown in <FIG> with a <NUM>-symbol slot, where the first two symbols contain Physical Downlink Control Channel (PDCCH) and the rest contains Physical Data Channel (PDCH), either Physical Downlink Data Channel (PDSCH) or Physical Uplink Data Channel (PUSCH).

Different subcarrier spacing values are supported in NR. The supported subcarrier spacing values (also referred to as different numerologies) are given by Δf = (<NUM> × <NUM>α) kHz where α is a non-negative integer. Δf = <NUM>kHz is the basic subcarrier spacing that is also used in LTE. The slot durations at different subcarrier spacings are shown in Table <NUM>. In the table, the numerology is denoted as (µ). Numerology with subscript <NUM> corresponds to <NUM>, numerology with subscript <NUM> corresponds to <NUM>, etc. It should be noted that the numerology for uplink and downlink can be different in NR.

In the frequency domain, a system bandwidth is divided into resource blocks (RBs), each corresponds to <NUM> contiguous subcarriers. The RBs are numbered starting with <NUM> from one end of the system bandwidth. The basic NR physical time-frequency resource grid is illustrated in <FIG>, where only one Resource Block (RB) within a <NUM>-symbol slot is shown. One OFDM subcarrier during one OFDM symbol interval forms one resource element (RE).

Downlink transmissions are dynamically scheduled, i.e., in each slot the gNB transmits downlink control information (DCI) over PDCCH about which UE data is to be transmitted to and which RBs in the current downlink slot the data is transmitted on. PDCCH is typically transmitted in the first one or two OFDM symbols in each slot in NR. The UE data are carried on PDSCH. A UE first detects and decodes PDCCH and the decoding is successfully, it then decodes the corresponding PDSCH based on the decoded control information in the PDCCH.

Uplink data transmissions are also dynamically scheduled using PDCCH. Similar to downlink, a UE first decodes uplink grants in PDCCH and then transmits data over PUSCH based the decoded control information in the uplink grant such as modulation order, coding rate, uplink resource allocation, etc..

For CSI feedback, NR has adopted an implicit CSI mechanism where a UE feedback the downlink channel state information including typically a transmission rank indicator (RI), a precoder matrix indicator (PMI), and channel quality indicator (CQI) for each codeword. The CQI/RI/PMI report can be either wideband or subband based on configuration.

The RI corresponds to a recommended number of layers that are to be spatially multiplexed and thus transmitted in parallel over the effective channel; the PMI identifies a recommended precoding matrix to use; the CQI represents a recommended modulation level (i.e., QPSK, <NUM> QAM, etc.) and coding rate for each codeword or TB. NR supports transmission of one or two codewords to a UE in a slot where two codewords are used for <NUM> to <NUM> layer transmission and one codeword is used for <NUM> to <NUM> layer transmission. There is thus a relation between a CQI and an SINR of the spatial layers over which the codewords are transmitted and for two codewords there are two CQI values fed back.

In NR, in addition to periodic and aperiodic CSI reporting as in LTE, semi-persistent CSI reporting is also supported. Thus, three types of CSI reporting will be supported in NR as follows:.

For CSI measurement and feedback, dedicated reference signals: CSI-RS are defined. A CSI-RS resource consist of between <NUM> and <NUM> CSI-RS ports and each port is typically transmitted on each transmit antenna (or virtual transmit antenna in case the port is precoded and mapped to multiple transmit antennas) and is used by a UE to measure downlink channel between each of the transmit antenna ports and each of its receive antenna ports. The antenna ports are also referred to as CSI-RS ports. The supported number of antenna ports in NR are {<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>}. By measuring the received CSI-RS, a UE can estimate the channel that the CSI-RS is traversing, including the radio propagation channel, potential precoding or beamforming, and antenna gains. The CSI-RS for the above purpose is also referred to as Non-Zero Power (NZP) CSI-RS but there are also zero power (ZP) CSI-RS used for other purposes than coherent channel measurements.

CSI-RS can be configured to be transmitted in certain REs in a slot and certain slots. <FIG> shows an example of a CSI-RS resource mapped to REs for <NUM> antenna ports, where one RE per RB per port is shown.

In addition, interference measurement resource for CSI feedback (CSI-IM) is also defined in NR for a UE to measure interference. A CSI-IM resource contains four REs, either four adjacent RE in frequency in the same OFDM symbol or two by two adjacent REs in both time and frequency in a slot. By measuring both the channel based on NZP CSI-RS and the interference based on CSI-IM, a UE can estimate the effective channel and noise plus interference to determine the CSI, i.e., rank, precoding matrix, and the channel quality.

Furthermore, a UE in NR may be configured to measure interference based on one or multiple NZP CSI-RS resource.

In NR, the following three types of CSI-RS transmissions are supported:.

In the case of aperiodic CSI-RS and/or aperiodic CSI reporting, the gNB RRC configures the UE with Sc CSI triggering states. Each triggering state contains the aperiodic CSI report setting to be triggered along with the associated aperiodic CSI-RS resource sets.

In 3GPP TS <NUM>, the reference resource in the time domain for different CSI reporting types are defined.

The CSI reference resource for a CSI report in uplink slot n'is defined by a single downlink slot n-nCSI_ref where <MAT>. Here, µDL and µUL are the subcarrier spacing configurations for DL and UL, respectively. The value of nCSI_ref depends on the type of CSI report.

For periodic and semi-persistent CSI reporting, nCSI_ref is defined as follows:.

For aperiodic CSI reporting, nCSI_ref is defined as follows:.

The 'valid downlink slot' is defined as follows in <NPL>:.

"A slot in a serving cell shall be considered to be a valid downlink slot if:.

In Release <NUM>, 3GPP started the work to prepare NR for operation in a Non-Terrestrial Network (NTN). The work was performed within the study item "NR to support Non-Terrestrial Networks" and resulted in <NPL>. In Release <NUM>, the work to prepare NR for operation in an NTN network continues with the study item "Solutions for NR to support Non-Terrestrial Network".

A satellite radio access network usually includes the following components:.

Two popular architectures are the Bent pipe transponder and the Regenerative transponder architectures. In the first case, the base station is located on earth behind the gateway, and the satellite operates as a repeater forwarding the feeder link signal to the service link, and vice versa. In the second case, the satellite is in the base station and the service link connects it to the earth-based core network.

Depending on the orbit altitude, a satellite may be categorized as low earth orbit (LEO), medium earth orbit (MEO), or geostationary earth orbit (GEO) satellite.

A communication satellite typically generates several beams over a given area. The footprint of a beam is usually in an elliptic shape, which has been traditionally considered as a cell. The footprint of a beam is also often referred to as a spotbeam. The spotbeam may move over the earth surface with the satellite movement or may be earth fixed with some beam pointing mechanism used by the satellite to compensate for its motion. The size of a spotbeam depends on the system design, which may range from tens of kilometers to a few thousands of kilometers.

<NUM> NR utilizes orthogonal frequency-division multiple access (OFDMA) as the multi-access scheme in the uplink. The transmissions from different UEs in a cell are time-aligned at the <NUM> NodeB (gNB) to maintain uplink orthogonality. Time alignment is achieved by using different Timing Advance (TA) values at different UEs to compensate for their different propagation delays. The required TA for a UE is roughly equal to the round-trip delay between the UE and gNB.

For the initial TA, after a UE has synchronized in the downlink and acquired certain system information, the UE transmits a random-access preamble (known as Message <NUM> (Msg1)) on physical random-access channel (PRACH). The gNB estimates the uplink timing from the received random-access preamble and responds Message <NUM> (Msg2) with a TA command. This allows the establishment of initial TA for the UE.

The propagation delays in terrestrial mobile systems are usually less than <NUM>. In contrast, the propagation delays in NTN are much longer, ranging from several milliseconds to hundreds of milliseconds depending on the altitudes of the spaceborne or airborne platforms in NTN. Dealing with such long propagation delays requires modifications of many timing aspects in NR from physical layer to higher layers, including the TA mechanism.

There are two types of timing advance mechanisms, which are referred to as large TA and small TA.

With large TA, each UE has a TA equal to its round-trip time and thus fully compensates its RTT. This is illustrated in <FIG> which is an illustration of large TA compensating full RTT. Accordingly, gNB DL-UL frame timings are aligned.

With small TA, each UE has a TA equal to its round-trip time minus a reference round-trip time, i.e., differential RTT. For example, the reference RTT can be the minimum RTT of a cell, and thus the differential RTT of any UE in the cell is always non-negative. The maximum differential RTT depends on the cell size and may range from sub-millisecond to a few milliseconds. With small TA, gNB needs to manage a DL-UL frame timing shift on the order of the reference RTT, as illustrated in <FIG>.

Improved systems and methods for determining a reference resource are needed.

Document "<NPL>, discloses physical layer control procedures. The following observations and proposals were made. Observation <NUM>: The NTN scheduling offset should take into account the elevation angle for a given beam spot within the satellite cell to compensate for the propagation delay on the access link. Proposal <NUM>: The gNB can adjust scheduling delay for UL HARQ ACK on PUCCH by n + K1' slots, where K1' = K1 + K1_ntnOffset to accommodate satellite RTT. Proposal <NUM>: The gNB can adjust scheduling delay for UL scheduling delay for UL data transmission on PUSCH by <MAT> slots to accommodate satellite RTT, where K2' = K2 + K2_ntnOffset. Proposal <NUM>: The gNB can adjust scheduling delay for UL scheduling delay for aperiodic or semi-persistent CSI report on PUSCH by n + K' slots, where K' = K + K_ntnOffset. Proposal <NUM>: The scheduling NTN scheduling offset values K_ntnOffset, K1_ntnOffset and K2_ntnOffset are broadcast in SIB. Proposal <NUM>: It is for further study whether the UE determines the FD(UL) relative to the centre of the beam from satellite system information or satellite ephemeris UE. Proposal <NUM>: It is for further study whether the UE obtains mapping of Physical Cell IDs to satellite beams / cells, where at least the following options can be considered (a) via RRC pre-configuration and (b) via system information broadcast by cellular network on SIB. Proposal <NUM>: The UE can search satellite beam / cell by detecting PCI-linked NR SSB. Observation <NUM>: The impact of latency in the DCI trigger / activation of aperiodic / semi-persistent CSI report on closed loop CSI/AMC effectiveness is un-known. Observation <NUM>: Whether multi-layer / multi-rank beamforming operations can be supported on the access link due to the link budget and satellite antenna configuration has not been discussed in RAN1. Proposal <NUM>: Whether the CSI measurement/reporting mechanism in NR Rel-<NUM> needs to be enhanced for NTN is for further study. Proposal <NUM>: Open-loop mechanisms for CSI/AMC are for further study. Observation <NUM>: Whether UE transmission power headroom is available to enable effective closed-loop power control has not been discussed in RAN1. Proposal <NUM>: Whether the closed-loop UL power control in NR Rel-<NUM> needs to be enhanced for NTN is for further study.

Systems and methods of reference resource determination are provided.

According to the present disclosure, methods, a wireless device and a base station according to the independent claims are provided. Developments are set forth in the dependent claims.

There are, proposed herein, various embodiments which address one or more of the issues disclosed herein.

Certain embodiments may provide one or more of the following technical advantage(s). The proposed solution enables CSI reporting with proper CSI reference resource determination in NTN scenarios. The proposed method is suitable for NTN scenarios where the RTT can be in the order of <NUM> to <NUM> of milliseconds. The benefits of the solutions are further exemplified in the drawings.

Core Network Node: As used herein, a "core network node" is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (PGW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing a Access and Mobility Function (AMF), a UPF, a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like.

<FIG> illustrates one example of a cellular communications system <NUM> in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system <NUM> is a <NUM> system (5GS) including a NR RAN or an Evolved Packet System (EPS) including a LTE RAN. In this example, the RAN includes base stations <NUM>-<NUM> and <NUM>-<NUM>, which in LTE are referred to as eNBs and in <NUM> NR are referred to as gNBs, controlling corresponding (macro) cells <NUM>-<NUM> and <NUM>-<NUM>. The base stations <NUM>-<NUM> and <NUM>-<NUM> are generally referred to herein collectively as base stations <NUM> and individually as base station <NUM>. Likewise, the (macro) cells <NUM>-<NUM> and <NUM>-<NUM> are generally referred to herein collectively as (macro) cells <NUM> and individually as (macro) cell <NUM>. The RAN may also include a number of low power nodes <NUM>-<NUM> through <NUM>-<NUM> controlling corresponding small cells <NUM>-<NUM> through <NUM>-<NUM>. The low power nodes <NUM>-<NUM> through <NUM>-<NUM> can be small base stations (such as pico or femto base stations) or Remote Radio Heads (RRHs), or the like. Notably, while not illustrated, one or more of the small cells <NUM>-<NUM> through <NUM>-<NUM> may alternatively be provided by the base stations <NUM>. The low power nodes <NUM>-<NUM> through <NUM>-<NUM> are generally referred to herein collectively as low power nodes <NUM> and individually as low power node <NUM>. Likewise, the small cells <NUM>-<NUM> through <NUM>-<NUM> are generally referred to herein collectively as small cells <NUM> and individually as small cell <NUM>. The cellular communications system <NUM> also includes a core network <NUM>, which in the 5GS is referred to as the <NUM> core (5GC). The base stations <NUM> (and optionally the low power nodes <NUM>) are connected to the core network <NUM>.

<FIG> illustrates a wireless communication system represented as a <NUM> network architecture composed of core Network Functions (NFs), where interaction between any two NFs is represented by a point-to-point reference point/interface. <FIG> can be viewed as one particular implementation of the system <NUM> of <FIG>.

Seen from the access side the <NUM> network architecture shown in <FIG> comprises a plurality of User Equipment (UEs) connected to either a Radio Access Network (RAN) or an Access Network (AN) as well as an Access and Mobility Management Function (AMF). Typically, the (R)AN comprises base stations, e.g., such as evolved Node Bs (eNBs) or NR base stations (gNBs) or similar. Seen from the core network side, the <NUM> core NFs shown in <FIG> include a Network Slice Selection Function (NSSF), an Authentication Server Function (AUSF), a Unified Data Management (UDM), an AMF, a Session Management Function (SMF), a Policy Control Function (PCF), and an Application Function (AF).

Reference point representations of the <NUM> network architecture are used to develop detailed call flows in the normative standardization. The N1 reference point is defined to carry signaling between the UE and AMF. The reference points for connecting between the AN and AMF and between the AN and UPF are defined as N2 and N3, respectively. There is a reference point, N11, between the AMF and SMF, which implies that the SMF is at least partly controlled by the AMF. N4 is used by the SMF and UPF so that the UPF can be set using the control signal generated by the SMF, and the UPF can report its state to the SMF. N9 is the reference point for the connection between different UPFs, and N14 is the reference point connecting between different AMFs, respectively. N15 and N7 are defined since the PCF applies policy to the AMF and SMP, respectively. N12 is required for the AMF to perform authentication of the UE. N8 and N10 are defined because the subscription data of the UE is required for the AMF and SMF.

The <NUM> core network aims at separating user plane and control plane. The user plane carries user traffic while the control plane carries signaling in the network. In <FIG>, the UPF is in the user plane and all other NFs, i.e., the AMF, SMF, PCF, AF, AUSF, and UDM, are in the control plane. Separating the user and control planes guarantees each plane resource to be scaled independently. It also allows UPFs to be deployed separately from control plane functions in a distributed fashion. In this architecture, UPFs may be deployed very close to UEs to shorten the Round Trip Time (RTT) between UEs and data network for some applications requiring low latency.

The core <NUM> network architecture is composed of modularized functions. For example, the AMF and SMF are independent functions in the control plane. Separated AMF and SMF allow independent evolution and scaling. Other control plane functions like the PCF and AUSF can be separated as shown in <FIG>. Modularized function design enables the <NUM> core network to support various services flexibly.

<FIG> illustrates a <NUM> network architecture using service-based interfaces between the NFs in the control plane, instead of the point-to-point reference points/interfaces used in the <NUM> network architecture of <FIG>. However, the NFs described above with reference to <FIG> correspond to the NFs shown in <FIG>. The service(s) etc. that a NF provides to other authorized NFs can be exposed to the authorized NFs through the service-based interface. In <FIG> the service based interfaces are indicated by the letter "N" followed by the name of the NF, e.g., Namf for the service based interface of the AMF and Nsmf for the service based interface of the SMF etc. The Network Exposure Function (NEF) and the Network Function (NF) Repository Function (NRF) in <FIG> are not shown in <FIG> discussed above. However, it should be clarified that all NFs depicted in <FIG> can interact with the NEF and the NRF of <FIG> as necessary, though not explicitly indicated in <FIG>.

Some properties of the NFs shown in <FIG> and <FIG> may be described in the following manner. The AMF provides UE-based authentication, authorization, mobility management, etc. A UE even using multiple access technologies is basically connected to a single AMF because the AMF is independent of the access technologies. The SMF is responsible for session management and allocates Internet Protocol (IP) addresses to UEs. It also selects and controls the UPF for data transfer. If a UE has multiple sessions, different SMFs may be allocated to each session to manage them individually and possibly provide different functionalities per session. The AF provides information on the packet flow to the PCF responsible for policy control in order to support Quality of Service (QoS). Based on the information, the PCF determines policies about mobility and session management to make the AMF and SMF operate properly. The AUSF supports authentication function for UEs or similar and thus stores data for authentication of UEs or similar while the UDM stores subscription data of the UE. The Data Network (DN), not part of the <NUM> core network, provides Internet access or operator services and similar.

<NUM> NR utilizes Orthogonal Frequency-Division Multiple Access (OFDMA) as the multi-access scheme in the uplink. The transmissions from different UEs in a cell are time-aligned at the <NUM> NodeB (gNB) to maintain uplink orthogonality. Time alignment is achieved by using different Timing Advance (TA) values at different UEs to compensate for their different propagation delays. The required TA for a UE is roughly equal to the round-trip delay between the UE and gNB.

For the initial TA, after a UE has synchronized in the downlink and acquired certain system information, the UE transmits a random-access preamble (known as Message <NUM> (Msg1)) on Physical Random-Access Channel (PRACH). The gNB estimates the uplink timing from the received random-access preamble and responds Message <NUM> (Msg2) with a TA command. This allows the establishment of initial TA for the UE.

There currently exist certain challenges. In NR Rel-<NUM>, the CSI reference resource definitions are designed to be suitable for terrestrial radio propagation environment where the round-trip delay is usually within <NUM>. However, in NTN scenarios, depending on whether small TA or large TA is used, the DL-UL frame timings at the gNB may or may not be aligned. Furthermore, the DL-UL frame timings at the UE will not be aligned due to the application of large or small TA. In addition, the TA value applied by the UE is UE specific as different UEs may have a different RTT. Furthermore, the range of RTT also depends on different NTN scenarios such as LEO/MEO/GEO. The current CSI reference resource definitions in NR Rel-<NUM> do not take into account such DL-UL frame misalignments and the application of large TAs prevalent in NTN scenarios. Hence, there is an open problem on how to determine CSI reference resource for NTN scenarios.

Systems and methods of reference resource determination are provided. In some embodiments, a method performed by a wireless device for determining a reference resource includes: receiving, from a network node, an indication of at least one configurable offset value to compensate for a Round Trip Time (RTT) value; receiving, from the network node, one or more configurations of resources for channel measurement and one or more configurations of measurement reporting; and determining, a reference resource for a measurement report to be reported in slot n' using the at least one configurable offset received from the network node. In some embodiments, this includes configurations of Channel State Information Reference Signals (CSI-RS) resources for channel measurement and/or CSI reporting. In this way, CSI reporting with proper CSI reference resource determination is enabled. In some embodiments, this is suitable for Non-Terrestrial Network (NTN) scenarios where the RTT can be in the order of <NUM> to <NUM> of milliseconds.

An example is next provided to illustrate the problem. Consider an example where the DL and the UL numerologies are <NUM> (i.e., µDL = µUL =<NUM>). Then for a CSI report in uplink slot n', the CSI reference resource is given by a single downlink slot n-nCSI_ref. Note that when the DL and UL numerologies are the same, <MAT>. In this example, periodic CSI reporting is assumed with a single CSI-RS resource being configured for channel measurement.

<FIG> shows the case when the existing CSI reference resource definition in NR Rel-<NUM> is used in an NTN scenario with a TA of eight slots. Recall that n = n' in this example since the UL and DL numerologies are the same. Also shown in the figure are the UL and DL frame timings at the gNB. In this case, using the existing CSI reference resource definition in NR Rel-<NUM> would result in the CSI reference resource at UE's DL slot n-nCSI_ref happening much later than UE's UL slot n' in which a UE needs to send a periodic CSI. This would mean the UE would possibly have to perform CSI measurement in a future slot in order to report the CSI in the current slot, which is not possible in practice.

Some embodiments of this disclosure propose a solution for determining CSI reference resource for a CSI report. <FIG> illustrates an exemplary embodiment. In some embodiments, a method performed by a wireless device for determining a reference resource includes receiving, from a network node, an indication of at least one configurable offset value (step <NUM>); receiving, from the network node, one or more configurations of resources for channel and/or interference measurement (step <NUM>), and further receiving, from the network node, one or more configurations of measurement reporting; and determining, a reference resource for a measurement report to be reported in slot n' using the at least one configurable offset received from the network node (step <NUM>). In some embodiments, the method also includes reporting the measurement report in uplink slot n' (step <NUM>).

Some embodiments of this disclosure propose a solution for determining CSI reference resource for a CSI report. <FIG> illustrates an exemplary embodiment. In some embodiments, a method performed by a base station for determining a reference resource includes one or more of: transmitting, to a wireless device, an indication of at least one configurable offset value (step <NUM>); transmitting, to the wireless device, one or more configurations of resources for channel and/or interference measurement, and further transmitting, to the wireless device, one or more configurations of measurement reporting (step <NUM>); and receiving, from the wireless device, a measurement report using a reference resource in slot n' where the reference resource is determined using the at least one configurable offset received from the network node (step <NUM>).

To determine a CSI reference resource suitable for NTN scenarios, the first step is for the UE to determine an offset value that will compensate for the full RTT or the differential RTT. In some embodiments, the UE will receive an indication from the gNB of an offset value. The offset value may be configurable to cover different NTN scenarios such as LEO/MEO/GEO. Furthermore, the configurable offset values may be dependent on different NR numerologies. The configurable offset value will compensate for the full RTT or the differential RTT. In some variants of this embodiment, the configurable offset is UE specifically configured to the UE by the gNB (for example, via RRC signaling). In some other variants of the embodiment, the indication of the offset value may be via broadcasting where the gNB broadcasts an offset value. This offset value broadcasted by the gNB may compensate for the common RTT. In some other embodiments, the gNB may indicate to the UE one offset via broadcasting to compensate for the common RTT and a second offset via higher layer signaling to compensate for differential RTT. If multiple such offset values are indicated by the gNB, then the UE will determine a combined offset by summing the first offset and the second offset.

In the second step, the UE receives configuration of CSI-RS resource(s) for channel measurement, and or CSI-IM resource(s) for interference measurement.

In the third step, for a CSI report to be reported in UL slot n' including the effect of the one way delay, the UE determines the CSI reference resource in a downlink slot n -nCSI_ref , taking into account the offset value determined from the <NUM>st step, where <MAT> and µDL and µUL are the subcarrier spacing configurations for DL and UL, respectively.

In the fourth step, the UE reports the CSI in UL slot n' including the effect of the one way delay.

An example is shown in <FIG> below, where the same subcarrier spacing is used for both DL and UL (i.e., n = n'). Note that for a CSI report to reach the gNB at UL slot n', the UE needs to send the CSI report four slots earlier to include the effect of the one way delay. Note that RTT = <NUM> slots in this example, hence four slots correspond to the one way delay between UE and gNB. The DL reference resource for the CSI report is in UE's DL slot n - nCSI,ref.

In the next few sections, detailed embodiments for step <NUM> are provided further discussing embodiments of how to determine the CSI reference resource by taking into account the offset value determined from step <NUM>.

In this embodiment, the CSI reference resource for periodic and semi-persistent CSI reporting is determined as outlined below. The value nCSI_ref that determines the CSI reference resource in the time domain is given as follows for periodic and semi-persistent CSI reporting:.

Note that Koffset is the time offset (e.g., in symbols or in slots) indicated by the gNB to the UE, or is derived from one or multiple time offset related parameter or parameters signaled by the gNB.

<FIG> shows the case when the proposed CSI reference resource determination method is used in an NTN scenario with a one way delay of eight slots. As in the previous examples, the same subcarrier spacing is used for both DL and UL (i.e., n = n') for this example. In this example, the UE receives an indication of an offset Koffset value equal to eight slots. The UE uses this offset in determining the CSI reference resource for a CSI report to be reported in UE's UL slot n'. As can be seen from <FIG>, the proposed solution results in the CSI reference resource happening much earlier than the slot in which the UE has to report periodic CSI. Hence, the proposed solution enables CSI reporting with proper CSI reference resource determination in NTN scenarios.

At the gNB, when it receives a CSI report in UL slot n', it knows the reference resource for the report is in DL slot -nCSI,ref.

In this embodiment, the CSI reference resource for aperiodic reporting is determined as outlined below. The value nCSI_ref that determines the CSI reference resource in the time domain is given as follows for aperiodic CSI reporting:.

If the UE is indicated by the DCI to report CSI in a future uplink slot and when aperiodic CSI-RS is used for channel measurement for the triggered CSI report, nCSI_ref is the smallest value greater than or equal to <MAT>, such that slot n-nCSI_ref corresponds to a valid downlink slot. Here, Koffset is the offset indicated by the gNB to the UE, Z' corresponds to the delay requirement in symbols between the end of the last symbol in time of the latest of: aperiodic CSI-RS resource for channel measurements, aperiodic CSI-IM used for interference measurements, and aperiodic NZP CSI-RS for interference measurement, and the first uplink symbol to carry the corresponding CSI report including the effect of the one way delay, and <MAT> denotes the number of symbols per slot.

If the UE is indicated by the DCI to report CSI in a future uplink slot and when periodic or semi-persistent CSI-RS is used for channel measurement for the triggered CSI report, nCSI_ref is the smallest value greater than or equal to Z/ <MAT>, such that slot n- nCSI_ref corresponds to a valid downlink slot. Here Z corresponds to the delay requirement in symbols between the end of the last symbol of the PDCCH triggering the CSI report and the first uplink symbol to carry the corresponding CSI report including the effect of the one way delay.

An alternative to the general embodiment above is now given. In this embodiment, the UE first receives configuration of CSI-RS resource(s) for channel measurement, and or CSI-IM resource(s) for interference measurement.

In the second step, for a CSI report to be reported in UL slot n'(UL slot n' here is defined from UE's perspective), the UE first determines the DL slot n with overlaps with the UL slot n'. The overlap may be a partial overlap or a full overlap. In case, the DL and UL subcarrier spacings are different, the DL slot n may be the first or the last among the DL slots that overlap with UL slot n'. <FIG> shows an example on how the UE determines the DL slot n from the UL slot n'. In this example, the DL slot n is determined as the slot that overlaps with UL slot n'.

Once the DL slot n is determined, the CSI reference resource is determined to be in DL slot n- nCSI_ref. , where nCSI_ref for this alternative embodiment is defined to be the same as in NR Rel-<NUM> (see section <NUM>.

<FIG> is a schematic block diagram of a radio access node <NUM> according to some embodiments of the present disclosure. The radio access node <NUM> may be, for example, a base station <NUM> or <NUM>. As illustrated, the radio access node <NUM> includes a control system <NUM> that includes one or more processors <NUM> (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory <NUM>, and a network interface <NUM>. The one or more processors <NUM> are also referred to herein as processing circuitry. In addition, the radio access node <NUM> includes one or more radio units <NUM> that each includes one or more transmitters <NUM> and one or more receivers <NUM> coupled to one or more antennas <NUM>. The radio units <NUM> may be referred to or be part of radio interface circuitry. In some embodiments, the radio unit(s) <NUM> is external to the control system <NUM> and connected to the control system <NUM> via, e.g., a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit(s) <NUM> and potentially the antenna(s) <NUM> are integrated together with the control system <NUM>. The one or more processors <NUM> operate to provide one or more functions of a radio access node <NUM> as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory <NUM> and executed by the one or more processors <NUM>.

As used herein, a "virtualized" radio access node is an implementation of the radio access node <NUM> in which at least a portion of the functionality of the radio access node <NUM> is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the radio access node <NUM> includes the control system <NUM> that includes the one or more processors <NUM> (e.g., CPUs, ASICs, FPGAs, and/or the like), the memory <NUM>, and the network interface <NUM> and the one or more radio units <NUM> that each includes the one or more transmitters <NUM> and the one or more receivers <NUM> coupled to the one or more antennas <NUM>, as described above. The control system <NUM> is connected to the radio unit(s) <NUM> via, for example, an optical cable or the like. The control system <NUM> is connected to one or more processing nodes <NUM> coupled to or included as part of a network(s) <NUM> via the network interface <NUM>. Each processing node <NUM> includes one or more processors <NUM> (e.g., CPUs, ASICs, FPGAs, and/or the like), memory <NUM>, and a network interface <NUM>.

In this example, functions <NUM> of the radio access node <NUM> described herein are implemented at the one or more processing nodes <NUM> or distributed across the control system <NUM> and the one or more processing nodes <NUM> in any desired manner. In some particular embodiments, some or all of the functions <NUM> of the radio access node <NUM> described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) <NUM>. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) <NUM> and the control system <NUM> is used in order to carry out at least some of the desired functions <NUM>. Notably, in some embodiments, the control system <NUM> may not be included, in which case the radio unit(s) <NUM> communicate directly with the processing node(s) <NUM> via an appropriate network interface(s).

<FIG> is a schematic block diagram of a UE <NUM> according to some embodiments of the present disclosure. As illustrated, the UE <NUM> includes one or more processors <NUM> (e.g., CPUs, ASICs, FPGAs, and/or the like), memory <NUM>, and one or more transceivers <NUM> each including one or more transmitters <NUM> and one or more receivers <NUM> coupled to one or more antennas <NUM>. The transceiver(s) <NUM> includes radio-front end circuitry connected to the antenna(s) <NUM> that is configured to condition signals communicated between the antenna(s) <NUM> and the processor(s) <NUM>, as will be appreciated by on of ordinary skill in the art. The processors <NUM> are also referred to herein as processing circuitry. The transceivers <NUM> are also referred to herein as radio circuitry. In some embodiments, the functionality of the UE <NUM> described above may be fully or partially implemented in software that is, e.g., stored in the memory <NUM> and executed by the processor(s) <NUM>. Note that the UE <NUM> may include additional components not illustrated in <FIG> such as, e.g., one or more user interface components (e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the UE <NUM> and/or allowing output of information from the UE <NUM>), a power supply (e.g., a battery and associated power circuitry), etc..

With reference to <FIG>, in accordance with an embodiment, a communication system includes a telecommunication network <NUM>, such as a 3GPP-type cellular network, which comprises an access network <NUM>, such as a RAN, and a core network <NUM>. The access network <NUM> comprises a plurality of base stations 2006A, 2006B, 2006C, such as Node Bs, eNBs, gNBs, or other types of wireless Access Points (APs), each defining a corresponding coverage area 2008A, 2008B, 2008C. Each base station 2006A, 2006B, 2006C is connectable to the core network <NUM> over a wired or wireless connection <NUM>. A first UE <NUM> located in coverage area 2008C is configured to wirelessly connect to, or be paged by, the corresponding base station 2006C. A second UE <NUM> in coverage area 2008A is wirelessly connectable to the corresponding base station 2006A.

It is noted that the host computer <NUM>, the base station <NUM>, and the UE <NUM> illustrated in <FIG> may be similar or identical to the host computer <NUM>, one of the base stations 2006A, 2006B, 2006C, and one of the UEs <NUM>, <NUM> of <FIG>, respectively.

The wireless connection <NUM> between the UE <NUM> and the base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE <NUM> using the OTT connection <NUM>, in which the wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve the e.g., data rate, latency, power consumption, etc. and thereby provide benefits such as e.g., reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc..

Unclaimed example <NUM>: A method performed by a wireless device for determining a reference resource, the method comprising one or more of: receiving (<NUM>), from a network node, an indication of at least one configurable offset value to compensate for a Round Trip Time, RTT, value; receiving (<NUM>), from the network node, one or more configurations of resources for channel and/or interference measurement, and further receiving, from the network node, one or more configurations of measurement reporting; and determining (<NUM>), a reference resource for a measurement report to be reported in slot n' using the at least one configurable offset received from the network node.

Unclaimed example <NUM>: The method of unclaimed example <NUM> wherein the at least one configurable offset value to compensate for the RTT value comprises at least one configurable offset value to compensate for a differential and/or common RTT.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the one or more configurations of resources for channel and/or interference measurement comprise one or more configurations of CSI-RS resources for channel and interference measurement.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the one or more configurations of measurement reporting comprises one or more configurations of CSI reporting.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the at least one configurable offset can depend on the numerology used.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the at least one configurable offset can be specifically configured to the wireless device by the network node.

Unclaimed example <NUM>: The method of unclaimed example <NUM> wherein the wireless device is configured via RRC signaling.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the at least one configurable offset can be broadcast by the network node in system information.

Unclaimed example <NUM>: The method of any of unclaimed example <NUM> wherein the at least one configurable offset can be sent in a SIB.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> further comprising: determining the time location of the CSI reference resource in downlink slot n- nCSI_ref where nCSI_ref is the smallest value greater than or equal to X · <NUM>µDL + Koffset wherein at least one of: a. Koffset is one or a combination (e.g., sum) of the at least one configurable offset; and b. n is given by <MAT>, and µDL/µUL are the downlink/uplink numerology.

Unclaimed example <NUM>: The method of unclaimed example <NUM> wherein X= <NUM> if single CSI-RS resource is configured for channel measurement.

Unclaimed example <NUM>: The method of unclaimed example <NUM> wherein X= <NUM> if multiple CSI-RS resources are configured for channel measurement.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> further comprising determining the time location of the CSI reference resource in downlink slot n- nCSI_ref where nCSI_ref is the smallest value greater than or equal to <MAT>, such that slot n- nCSI_ref corresponds to a valid downlink slot wherein at least one of: a. Koffset is one or a combination (e.g., sum) of the at least one configurable offset; b. n is given by <MAT>, and µDL/µUL are the downlink/uplink numerology; and c. Z' is a parameter that determines delay requirements and <MAT> is the number of symbols per slot.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> further comprising: reporting (<NUM>) the measurement report in uplink slot n'.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the network node is a gNB.

Unclaimed example <NUM>: The method of any of the previous unclaimed examples, further comprising: providing user data; and forwarding the user data to a host computer via the transmission to the base station.

Unclaimed example <NUM>: A method performed by a base station for determining a reference resource, the method comprising one or more of: transmitting (<NUM>), to a wireless device, an indication of at least one configurable offset value to compensate for a Round Trip Time, RTT, value; transmitting (<NUM>), to the wireless device, one or more configurations of resources for channel and/or interference measurement, and further transmitting, to the wireless device, one or more configurations of measurement reporting; and receiving (<NUM>), from the wireless device, a measurement report using a reference resource in slot n' where the reference resource is determined using the at least one configurable offset received from the network node.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the at least one configurable offset can be specifically configured to the wireless device by the base station.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the at least one configurable offset can be broadcast by the base station in system information.

Unclaimed example <NUM>: The method of unclaimed example <NUM> wherein X= <NUM> if multiple CSI-RS resources are configured for channel measurement.

Unclaimed example <NUM>: The method of any of unclaimed examples <NUM> to <NUM> wherein the base station is a gNB.

Unclaimed example <NUM>: The method of any of the previous unclaimed examples, further comprising: obtaining user data; and forwarding the user data to a host computer or a wireless device.

Unclaimed example <NUM>: A wireless device for determining a reference resource, the wireless device comprising: processing circuitry configured to perform any of the steps of any of the Group A unclaimed examples; and power supply circuitry configured to supply power to the wireless device.

Unclaimed example <NUM>: A base station for determining a reference resource, the base station comprising: processing circuitry configured to perform any of the steps of any of the Group B unclaimed examples; and power supply circuitry configured to supply power to the base station.

Unclaimed example <NUM>: A User Equipment, UE, for determining a reference resource, the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A unclaimed examples; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

Unclaimed example <NUM>: A communication system including a host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward the user data to a cellular network for transmission to a User Equipment, UE; wherein the cellular network comprises a base station having a radio interface and processing circuitry, the base station's processing circuitry configured to perform any of the steps of any of the Group B unclaimed examples.

Unclaimed example <NUM>: The communication system of the previous unclaimed example further including the base station.

Unclaimed example <NUM>: The communication system of the previous <NUM> unclaimed examples, further including the UE, wherein the UE is configured to communicate with the base station.

Unclaimed example <NUM>: The communication system of the previous <NUM> unclaimed examples, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the UE comprises processing circuitry configured to execute a client application associated with the host application.

Unclaimed example <NUM>: A method implemented in a communication system including a host computer, a base station, and a User Equipment, UE, the method comprising: at the host computer, providing user data; and at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the base station performs any of the steps of any of the Group B unclaimed examples.

Unclaimed example <NUM>: The method of the previous unclaimed example, further comprising, at the base station, transmitting the user data.

Unclaimed example <NUM>: The method of the previous <NUM> unclaimed examples, wherein the user data is provided at the host computer by executing a host application, the method further comprising, at the UE, executing a client application associated with the host application.

Unclaimed example <NUM>: A User Equipment, UE, configured to communicate with a base station, the UE comprising a radio interface and processing circuitry configured to perform the method of the previous <NUM> unclaimed examples.

Unclaimed example <NUM>: A communication system including a host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward user data to a cellular network for transmission to a User Equipment, UE; wherein the UE comprises a radio interface and processing circuitry, the UE's components configured to perform any of the steps of any of the Group A unclaimed examples.

Unclaimed example <NUM>: The communication system of the previous unclaimed example, wherein the cellular network further includes a base station configured to communicate with the UE.

Unclaimed example <NUM>: The communication system of the previous <NUM> unclaimed examples, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the UE's processing circuitry is configured to execute a client application associated with the host application.

Unclaimed example <NUM>: A method implemented in a communication system including a host computer, a base station, and a User Equipment, UE, the method comprising: at the host computer, providing user data; and at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the UE performs any of the steps of any of the Group A unclaimed examples.

Unclaimed example <NUM>: The method of the previous unclaimed example, further comprising at the UE, receiving the user data from the base station.

Unclaimed example <NUM>: A communication system including a host computer comprising: communication interface configured to receive user data originating from a transmission from a User Equipment, UE, to a base station; wherein the UE comprises a radio interface and processing circuitry, the UE's processing circuitry configured to perform any of the steps of any of the Group A unclaimed examples.

Unclaimed example <NUM>: The communication system of the previous unclaimed example, further including the UE.

Unclaimed example <NUM>: The communication system of the previous <NUM> unclaimed examples, further including the base station, wherein the base station comprises a radio interface configured to communicate with the UE and a communication interface configured to forward to the host computer the user data carried by a transmission from the UE to the base station.

Unclaimed example <NUM>: The communication system of the previous <NUM> unclaimed examples, wherein: the processing circuitry of the host computer is configured to execute a host application; and the UE's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data.

Unclaimed example <NUM>: The communication system of the previous <NUM> unclaimed examples, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing request data; and the UE's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data in response to the request data.

Unclaimed example <NUM>: A method implemented in a communication system including a host computer, a base station, and a User Equipment, UE, the method comprising: at the host computer, receiving user data transmitted to the base station from the UE, wherein the UE performs any of the steps of any of the Group A unclaimed examples.

Unclaimed example <NUM>: The method of the previous unclaimed example, further comprising, at the UE, providing the user data to the base station.

Unclaimed example <NUM>: The method of the previous <NUM> unclaimed examples, further comprising: at the UE, executing a client application, thereby providing the user data to be transmitted; and at the host computer, executing a host application associated with the client application.

Unclaimed example <NUM>: The method of the previous <NUM> unclaimed examples, further comprising: at the UE, executing a client application; and at the UE, receiving input data to the client application, the input data being provided at the host computer by executing a host application associated with the client application; wherein the user data to be transmitted is provided by the client application in response to the input data.

Unclaimed example <NUM>: A communication system including a host computer comprising a communication interface configured to receive user data originating from a transmission from a User Equipment, UE, to a base station, wherein the base station comprises a radio interface and processing circuitry, the base station's processing circuitry configured to perform any of the steps of any of the Group B unclaimed examples.

Unclaimed example <NUM>: The communication system of the previous <NUM> unclaimed examples, wherein: the processing circuitry of the host computer is configured to execute a host application; and the UE is configured to execute a client application associated with the host application, thereby providing the user data to be received by the host computer.

Unclaimed example <NUM>: A method implemented in a communication system including a host computer, a base station, and a User Equipment, UE, the method comprising: at the host computer, receiving, from the base station, user data originating from a transmission which the base station has received from the UE, wherein the UE performs any of the steps of any of the Group A unclaimed examples.

Unclaimed example <NUM>: The method of the previous unclaimed example, further comprising at the base station, receiving the user data from the UE.

Unclaimed example <NUM>: The method of the previous <NUM> unclaimed examples, further comprising at the base station, initiating a transmission of the received user data to the host computer.

Claim 1:
A method performed by a wireless device for determining a Channel State Information, CSI, reference resource, the method comprising:
receiving (<NUM>), from a network node, an indication of at least one configurable offset value, wherein the at least one configurable offset value comprises at least one configurable offset value to compensate for a Round Trip Time, RTT, value;
receiving (<NUM>), from the network node, one or more configurations of CSI Resource Signal, CSI-RS, resources for channel measurement and CSI Interference Measurement, CSI-IM, resources for interference measurement, and one or more configurations of CSI reporting;
determining (<NUM>) a CSI reference resource for a CSI report to be reported in an uplink slot n' using the at least one configurable offset value received from the network node; and
reporting (<NUM>) the CSI report in the uplink slot n'.