Method and apparatus for receiver assisted transmission in shared spectrum

Abstract

Upon determining that a communication channel in a shared spectrum is idle, a gNB can transmit downlink control information (DCI) triggering a user equipment (UE) to measure resources to determine whether the communication channel is available to the UE. The UE triggered by the DCI can measure energy received on the resources, generate a measurement report, and transmit the measurement report to the gNB. Based on the measurement report, the gNB can determine whether to transmit data to the UE in the communication channel.

Description

[0001] This patent application claims priority to U.S. Provisional Application No. 63 / 062,204, filed August 6, 2020, entitled “Method and Apparatus for Receiver Assisted Transmission in Shared Spectrum,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present invention generally relates to wireless communication, and in certain embodiments to techniques and mechanisms for receiver-assisted transmission in shared or unlicensed spectrum. Background Technology

[0003] Unlicensed spectrum (also known as unlicensed spectrum or shared spectrum) has recently attracted significant interest from cellular operators. Long Term Evolution Licensed Assisted Access (LTE-LAA) is specified in 3GPP LTE Releases (Rel) 13 and 14. More recently, in New Radio Unlicensed (NR-U), operation in unlicensed spectrum (or shared spectrum) is specified in 3GPP New Radio (NR) Release 16 (3GPP TS 38.213, the entire contents of which are incorporated herein by reference).

[0004] 3GPP and IEEE technologies operating in unlicensed spectrum use Listen Before Talk (LBT) channel access. In some regions, such as the European Union (EU) and Japan, LBT rules are typically enforced by spectrum regulators to reduce interference risks and provide a fairer coexistence mechanism. The LBT mechanism requires the transmitter to check for other occupants on the channel before transmission, and if the channel is occupied, transmission is postponed.

[0005] Specifically, EU LBT rules, such as the European Telecommunications Standards Institute (ETSI) European Standard (EN) 301893 for the 5 GHz band, use clear channel assessment (CCA) to determine whether a channel is available for transmission. CCA checks if the energy received on the channel exceeds a CCA threshold. If the detected energy exceeds the CCA threshold, the channel is considered to be in use (busy); otherwise, the channel is considered idle. If the channel is idle, the transmitter can transmit within at least a portion (e.g., 80%) of the total channel bandwidth for a duration of channel occupancy time (COT). ETSI EN 301893 (the entire contents of which are incorporated herein by reference) also specifies the maximum COT duration for transmitted pulses. In 3GPP NR-U Rel 16 (TS 37.213, the entire contents of which are incorporated herein by reference), the maximum COT (MCOT) duration is a function of the channel access priority class (CAPC). As defined in TS 37.213, to determine the COT, the transmission interval duration is included in the COT if the transmission interval (the interval between consecutive transmissions) is less than or equal to 25 μs. A transmission pulse is defined as a group of transmissions with an interval of no more than 16 μs (i.e., a transmission interval), and if the interval is greater than 16 μs, the group of transmissions is considered a single transmission.

[0006] 3GPP Rel 16 (TS 37.213) defines several channel access types in unlicensed spectrum for downlink (DL) and uplink (UL).

[0007] In Type 1 DL channel access, during delay duration After the first detection that the channel is idle during the duration of the listening slot, and after a randomly started counter N (decrementing in each idle listening slot) reaches 0, the gNB can transmit. The listening slot duration can be 9 μs. Type 1 DL channel access can be used before starting a new COT, the duration of which depends on traffic priority and can be up to 10 ms.

[0008] Type 2 DL channel access includes a deterministic duration of channel listening, during which the channel needs to be listened to as idle. Type 2 DL channel access includes Type 2A, Type 2B, and Type 2C channel access.

[0009] If the listening channel is idle for at least 25 μs before transmission, Type 2A channel access is permitted for transmission.

[0010] If the listening channel is idle for at least 16 μs before transmission, type 2B channel access is permitted to transmit.

[0011] Type 2C channel access allows transmission for a duration not exceeding 584 μs without prior channel sniffing.

[0012] Type 2A DL channel access procedure is applicable to shared COT after a transmission from user equipment (UE) and is applicable to transmissions including discovery pulses (duration of up to 1 ms and duty cycle of up to 1 / 20).

[0013] Type 2B or Type 2C DL channel access procedures are respectively applicable after the UE's transmission. or as high as The shared channel occupancy after the interval.

[0014] Similar to the DL channel access type, TS 37.213 defines the UL channel access procedure. As in Type 1A DL channel access, Type 1 UL channel access is based on detecting that the channel is idle for a fixed duration Td of delay, and then continues until a randomly decreasing backoff counter N for each idle listening slot reaches 0. Type 2 UL channel access requires that the channel be idle for a fixed (deterministic) duration prior to transmission, where Type 2A UL channel access requires at least 25 μs of idle channel duration before transmission, and Type 2B UL channel access requires at least 16 μs of idle channel duration before transmission. Type 2C allows transmissions up to 584 μs in length without any channel listening. Summary of the Invention

[0015] The methods and apparatus for receiver-assisted transmission in shared spectrum described in the embodiments of the present invention can generally achieve the desired technical effects.

[0016] According to one aspect of the present invention, a method is provided, comprising: when a gNB needs to transmit data to a first user equipment (UE), the gNB determines whether a communication channel within a shared spectrum is idle and available; when the communication channel is determined to be idle, the gNB transmits first downlink control information (DCI) to trigger the first UE to measure resources to determine whether the communication channel is available to the first UE; after transmitting the first DCI, the gNB receives a first measurement report from the first UE regarding the measurement of the resources; based on the first measurement report, the gNB determines whether to transmit the data to the first UE in the communication channel.

[0017] Optionally, in any of the foregoing aspects, the method further includes: when it is determined from the first measurement report that the communication channel is available to the first UE, the gNB transmits the data to the first UE in the communication channel.

[0018] Optionally, in any of the foregoing aspects, the method further includes: the gNB receiving from the first UE a negative acknowledge (NACK) message indicating that the first UE has not successfully received the data; after receiving the NACK message, the gNB receiving from the first UE a second measurement report regarding the measurement of the resource; and when it is determined from the second measurement report that the communication channel is available to the first UE, the gNB retransmitting the data to the first UE in the communication channel.

[0019] Optionally, in any of the foregoing aspects, the method further includes: after receiving the first measurement report and before transmitting the data, the gNB re-determines the availability of the communication channel.

[0020] Optionally, in any of the foregoing aspects, the data may be transmitted in the resource or a subset thereof.

[0021] Optionally, in any of the foregoing aspects, the method further includes: when it is determined from the first measurement report that the communication channel is unavailable to the first UE, the gNB sends a second DCI to trigger the first UE to remeasure the resource to determine whether the communication channel is available to the first UE.

[0022] Optionally, in any of the foregoing aspects, the communication channel is not available to the first UE, and the method further includes: after receiving the first measurement report, within a preset time period, the gNB receives a second measurement report from the first UE; and when it is determined from the second measurement report that the communication channel is available to the first UE, the gNB transmits the data to the first UE.

[0023] Optionally, in any of the foregoing aspects, the gNB determining whether the communication channel is idle includes: the gNB performing a clear channel assessment (CCA) on the communication channel.

[0024] Optionally, in any of the foregoing aspects, the resource includes one or more carriers, or one or more resource sets.

[0025] Optionally, in any of the foregoing aspects, the resource includes channel state information-interference measurement (CSI-IM) resources or a CSI-IM resource set.

[0026] Optionally, in any of the foregoing aspects, the resource includes channel state information-reference signal (CSI-RS) resources or a CSI-RS resource set.

[0027] Optionally, in any of the foregoing aspects, the resource includes carrier bandwidth or a subset of the carrier bandwidth.

[0028] Optionally, in any of the foregoing aspects, the resources include time resources, frequency resources, spatial resources, or a combination of time resources, frequency resources, and spatial resources.

[0029] Optionally, in any of the foregoing aspects, the first measurement report indicates whether the energy detected on the resource or a subset of the resources exceeds a threshold; whether the resource or the subset of the resources is idle; or the energy detected on the resource or the subset of the resources.

[0030] Optionally, in any of the foregoing aspects, the first measurement report includes an interference measurement indicator (IMI) indicating the measurement results of the resource or a subset of the resource.

[0031] Optionally, in any of the foregoing aspects, the method further includes: the gNB transmitting first information about the resource.

[0032] Optionally, in any of the foregoing aspects, the method further includes: the gNB transmitting second information, the second information including any one or more of the following: resources for reporting resource measurements; quasi-co-location (QCL) information of the measured resources; transmission configuration indication (TCI) status indicating the QCL type of the measured resources; the measurement time period of the resource measurement; or a measurement threshold.

[0033] Optionally, in any of the foregoing aspects, the first information or the second information is transmitted in the first DCI or via higher-layer signaling.

[0034] Optionally, in any of the foregoing aspects, transmitting the first DCI includes: the gNB transmitting the first DCI to a group of UEs including the first UE, triggering each UE in the group of UEs to measure corresponding resources to determine whether the communication channel is available to the corresponding UE.

[0035] Optionally, in any of the foregoing aspects, the first DCI has a cyclic redundancy check (CRC) scrambled using a group radio network temporary identifier (RNTI) associated with the group of UEs, and for each UE, the first DCI includes one or more of the following: the corresponding resource of the corresponding UE; QCL information of the corresponding measurement resource of the corresponding UE; a measurement time window; a measurement threshold; or resources for reporting measurements.

[0036] Optionally, in any of the foregoing aspects, the first DCI further includes a field for requesting the first UE to report an L1-IM report or a CSI-RS report regarding the measurement of the resource.

[0037] Optionally, in any of the foregoing aspects, the first DCI further includes one or more of the following: a channel state information-interference measurement (CSI-IM) time-domain indicator indicating the CSI-IM configuration for interference measurement; a periodicity-and-offset parameter indicating the period and timing offset for the interference measurement and reporting; or an IMI bit length parameter indicating the number of bits used to encode the measurement results of the interference measurement.

[0038] Optionally, in any of the foregoing aspects, the first DCI further includes one or more of the following: a channel state information-interference measurement (CSI-IM) time-domain indicator indicating the CSI-IM configuration for the measurement of interference statistics; a period and offset parameter indicating the period and timing offset for the measurement and reporting of the interference statistics; or a statistics type parameter indicating the type of interference statistics to be reported by the UE for each resource, the type of interference statistics including the following values ​​within the measurement duration period: average channel idle duration, standard deviation of channel idle duration, average channel busy duration, longest channel idle duration, shortest channel idle duration, longest channel busy duration, or shortest channel busy duration.

[0039] According to another aspect of the present invention, a method is provided, comprising: a user equipment (UE) receiving first downlink control information (DCI) from a gNB, triggering the UE to measure resources to determine whether a communication channel in a shared spectrum is available to the UE; the UE performing a first measurement on the energy received on the resources after being triggered by the DCI; the UE generating a first measurement report based on the first measurement; and the UE transmitting the first measurement report to the gNB.

[0040] Optionally, in any of the foregoing aspects, the method further includes: when the communication channel is available to the UE, the UE receives data from the gNB in ​​the communication channel of the shared spectrum after transmitting the first measurement report.

[0041] Optionally, in any of the foregoing aspects, the method further includes: the UE transmitting a negative acknowledge (NACK) message to the gNB indicating that the UE has not successfully received the data; the UE performing a second measurement on the energy received on the resource to determine whether the communication channel is available; the UE transmitting a second measurement report to the gNB, the second measurement report being based on the second measurement; and after transmitting the second measurement report, the UE receiving the data retransmitted by the gNB in ​​the communication channel of the shared spectrum.

[0042] Optionally, in any of the foregoing aspects, the data may be received in the resource or in a subset of the resource.

[0043] Optionally, in any of the foregoing aspects, the method further includes: when the communication channel is unavailable to the UE, the UE receives a second DCI from the gNB, triggering the UE to remeasure the resource to determine whether the communication channel is available.

[0044] Optionally, in any of the foregoing aspects, the communication channel is not available to the UE, and the method further includes: the UE performing a second measurement on the resource to generate a second measurement report; the UE transmitting the second measurement report to the gNB; and after transmitting the second measurement report, the UE receiving the data from the gNB in ​​the communication channel.

[0045] Optionally, in any of the foregoing aspects, the resource includes one or more carriers, or one or more resource sets.

[0046] Optionally, in any of the foregoing aspects, the resource includes channel state information-interference measurement (CSI-IM) resources or a CSI-IM resource set.

[0047] Optionally, in any of the foregoing aspects, the resource includes channel state information-reference signal (CSI-RS) resources or a CSI-RS resource set.

[0048] Optionally, in any of the foregoing aspects, the resource includes carrier bandwidth or a subset of the carrier bandwidth.

[0049] Optionally, in any of the foregoing aspects, the resources include time resources, frequency resources, spatial resources, or a combination of time resources, frequency resources, and spatial resources.

[0050] Optionally, in any of the foregoing aspects, the first measurement report indicates whether the energy detected on the resource or a subset of the resources exceeds a threshold; whether the resource or the subset of the resources is idle; or the energy detected on the resource or the subset of the resources.

[0051] Optionally, in any of the foregoing aspects, the first measurement report includes an interference measurement indicator (IMI) indicating the measurement results of the resource or a subset of the resource.

[0052] Optionally, in any of the foregoing aspects, performing the first measurement includes: the UE generating a component carrier-received signal strength indicator (CC-RSSI) based on the energy received on the resource during the measurement period.

[0053] Optionally, in any of the foregoing aspects, the method further includes: the UE receiving first information about the resource from the gNB.

[0054] Optionally, in any of the foregoing aspects, the method further includes: the UE receiving second information from the gNB, the second information including any one or more of the following: resources for reporting resource measurements; quasi-co-location (QCL) information of the measured resources; transmission configuration indication (TCI) status indicating the QCL type of the measured resources; the measurement time period of the resource measurement; or a measurement threshold.

[0055] Optionally, in any of the foregoing aspects, the first information or the information is received in the first DCI or via higher-layer signaling.

[0056] Optionally, in any of the foregoing aspects, the first DCI triggers each of the group of UEs to measure the corresponding resources to determine whether the communication channel is available to the corresponding UE.

[0057] Optionally, in any of the foregoing aspects, the first DCI has a cyclic redundancy check (CRC) scrambled using a group radio network temporary identifier (RNTI) associated with the group of UEs.

[0058] Optionally, in any of the foregoing aspects, the first DCI further includes a field for requesting the UE to report an L1-IM report or a CSI-RS report.

[0059] Optionally, in any of the foregoing aspects, the first DCI further includes one or more of the following: a channel state information-interference measurement (CSI-IM) time-domain indicator indicating the CSI-IM configuration for interference measurement; a period and offset parameter indicating the period and offset used for the interference measurement and reporting; or an IMI bit length parameter indicating the number of bits used to encode the measurement results of the interference measurement.

[0060] Optionally, in any of the foregoing aspects, the first measurement report includes an interference statistics measurement indicator (STA-IMI) indicating the measurement statistics of the resource or a subset of the resource, the statistics including the following values ​​within the measurement duration period: average channel idle duration, standard deviation of the channel idle duration, average channel busy duration, longest channel idle duration, shortest channel idle duration, longest channel busy duration, and shortest channel busy duration.

[0061] According to another aspect of the invention, an apparatus is provided, comprising: a non-transient memory memory including instructions; and one or more processors communicating with the memory memory, wherein the instructions, when executed by the one or more processors, cause the apparatus to perform the method of any of the foregoing aspects.

[0062] According to another aspect of the invention, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium stores computer instructions that, when executed by one or more processors of a device, cause the device to perform the methods of any of the foregoing aspects.

[0063] According to another aspect of the present invention, a system is provided, comprising: user equipment (UE); a gNB communicating with the UE; wherein the gNB is configured to perform the following operations: when the gNB wants to send data to the UE, determining whether a communication channel in a shared spectrum is idle and available; when the communication channel is determined to be available, sending downlink control information (DCI) to trigger the UE to measure resources to determine whether the communication channel is available to the UE; after sending the DCI, receiving a measurement report of the measurement of the resources from the UE; and determining, based on the measurement report, whether to transmit the data to the UE in the communication channel; wherein the UE is configured to perform the following operations: receiving the DCI from the gNB; after being triggered by the DCI, performing a first measurement on the energy received on the resources; generating the measurement report based on the first measurement; and transmitting the measurement report.

[0064] The above aspects enable the transmitter to obtain interference information about the channel in the shared spectrum for the receiver, determine the interference status for the receiver, and decide whether to transmit to the receiver based on the interference status. This greatly improves the communication performance in the shared spectrum. Attached Figure Description

[0065] To gain a more complete understanding of the invention and its effects, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0066] Figure 1 A schematic diagram of an exemplary wireless communication network is shown;

[0067] Figure 2 An exemplary communication system is illustrated, and mathematical expressions for the signals transmitted in the communication system are provided;

[0068] Figure 3A and Figure 3B A schematic diagram of an exemplary conventional system for analog beam control and digital beamforming is shown;

[0069] Figure 4 A schematic diagram illustrating an exemplary conventional transmission timing for frame-based equipment (FBE) operation is shown.

[0070] Figure 5 A flowchart of a traditional carrier sensing method is shown;

[0071] Figure 6 The flowchart of the traditional method of listening first and then speaking is shown;

[0072] Figure 7A schematic diagram illustrating an exemplary conventional Wi-Fi channel access process is shown;

[0073] Figure 8A A schematic diagram of an exemplary wide beam pattern is shown;

[0074] Figure 8B A schematic diagram of an exemplary narrow beam pattern is shown;

[0075] Figure 9 A schematic diagram illustrating an example of the blind spot problem in directional communication is shown;

[0076] Figure 10 A schematic diagram illustrating exemplary resources allocated by multiple gNBs is shown;

[0077] Figure 11 A schematic diagram of an exemplary method for receiver-assisted channel access in unlicensed spectrum is shown;

[0078] Figure 12 A schematic diagram of another exemplary method for receiver-assisted channel access in unlicensed spectrum is shown;

[0079] Figure 13 A schematic diagram of another exemplary method for receiver-assisted channel access in unlicensed spectrum is shown;

[0080] Figure 14 A schematic diagram of another exemplary method for receiver-assisted channel access in unlicensed spectrum is shown;

[0081] Figure 15 A schematic diagram of another exemplary method for receiver-assisted channel access in unlicensed spectrum is shown;

[0082] Figure 16 A schematic diagram of another exemplary method for receiver-assisted channel access in unlicensed spectrum is shown;

[0083] Figure 17 A schematic diagram of another exemplary method for receiver-assisted channel access in unlicensed spectrum is shown;

[0084] Figure 18 A schematic diagram of another exemplary method for receiver-assisted channel access in unlicensed spectrum is shown;

[0085] Figure 19 A schematic diagram of an embodiment of the processing system is shown;

[0086] Figure 20 A schematic diagram of an exemplary transceiver is shown.

[0087] Unless otherwise indicated, corresponding numbers and symbols in different figures generally refer to corresponding parts. The figures are drawn to clearly illustrate relevant aspects of the embodiments and are not necessarily drawn to scale. Detailed Implementation

[0088] The following sections will discuss in detail the fabrication and use of embodiments of the present invention. However, it should be understood that the concepts disclosed herein can be embodied in various specific contexts, and the specific embodiments discussed herein are merely illustrative and not intended to limit the scope of the claims. Furthermore, it should be understood that various changes, substitutions, and modifications can be made to this document without departing from the spirit and scope of the invention as defined by the appended claims.

[0089] To expand communication spectrum and capacity, wireless communication using unlicensed spectrum (also known as unlicensed spectrum or shared spectrum) has been considered and discussed. However, communication using shared spectrum can experience performance degradation due to unpredictable interference, particularly in the case of high-frequency band communication. For example, a transmitter might detect channel availability and perform a directional transmission to a receiver on the channel, while the receiver might encounter interference from another directional transmission that is undetectable by the transmitter. Mechanisms are desired to mitigate or avoid receiver-side interference.

[0090] Various embodiments of the present invention provide methods for receiver-assisted channel access in cellular networks. In some embodiments, the receiver may provide interference information to the transmitter from the receiver side. This information can help the transmitter make decisions regarding subsequent data transmissions to the receiver. As an example, based on this information, if the receiver is subject to severe interference (e.g., in one direction), the transmitter may avoid transmitting to the receiver in that direction. As another example, the transmitter may use this information to determine the modulation and coding scheme (MCS) level for the receiver, or selectively use a shared spectrum channel with less interference.

[0091] In some embodiments, when it is determined that a communication channel in the shared spectrum is idle and available, the gNB may send downlink control information (DCI) to trigger the user equipment (UE) to measure one or more resources to determine whether the communication channel is available to the UE. Resources may include carrier waves. Resources may include the time resources of the communication channel, the frequency resources of the communication channel, the spatial resources of the communication channel (e.g., beam direction), or combinations thereof. After being triggered by the DCI, the UE may measure the energy received on one or more resources, generate a measurement report, and send the measurement report to the gNB. Based on the measurement report, the gNB may determine whether to transmit data to the UE in the communication channel.

[0092] Figure 1 An exemplary wireless communication system 100 is illustrated. The communication system 100 includes an access node 110 having a coverage area 111. The access node 110 serves multiple user equipment (UEs), including UE 120 and UE 122. Transmissions from the access node 110 to the UEs are referred to as downlink (DL) transmissions and occur on the downlink channel (in...). Figure 1 (Shown by solid arrows in the image); the transmission from the UE to the access node 110 is called uplink (UL) transmission, and it occurs on the uplink channel (in... Figure 1 (Indicated by dashed arrows). Services can be provided to multiple UEs by a service provider connected to access node 110 via backhaul network 130 (e.g., the Internet). Wireless communication system 100 may include multiple distributed access nodes 110.

[0093] In typical communication systems, several operating modes exist. In cellular mode, multiple UEs communicate through the access node 110. In device-to-device communication modes, such as proximity service (ProSe) mode, UEs can communicate directly with each other. Access nodes are also commonly referred to as Node B, evolved Node B (eNB), next-generation (NG) base station (gNB), master eNB (MeNB), secondary eNB (SeNB), master gNB (MgNB), secondary gNB (SgNB), network controller, control node, base station, access point, transmission point (TP), transmission-reception point (TRP), cell, carrier, macro cell, femtocell, picocell, relay, customer premises equipment (CPE), etc. UE can also be referred to as mobile station, mobile device, terminal, terminal equipment, user, subscriber, site, communication equipment, CPE, relay, Integrated Access and Backhaul (IAB) relay, etc. It should be noted that when using relays (based on relay, picocell, CPE, etc.), especially multi-hop relays, the boundary between the controller and the nodes controlled by the controller can become blurred, and in a dual-node (controller or node controlled by the controller) deployment, the first node providing configuration or control information to the second node is considered the controller. Similarly, the concepts of UL and DL transmission can be extended.

[0094] A cell may include one or more bandwidth parts (BWPs) allocated to the UE for UL or DL. Each BWP may have its own BWP-specific system parameters and configuration. It should be noted that not all BWPs need to be active for the UE simultaneously. A cell may correspond to one or more carriers. Typically, a cell (e.g., a primary cell (PCell) or a secondary cell (SCell)) is a component carrier (e.g., a primary component carrier (PCC) or a secondary CC (SCC)). For some cells, each cell may include multiple carriers in the UL, one of which is called an UL carrier or a non-supplementary UL (non-SUL) carrier, which has an associated DL; while other carriers are called supplementary UL (SUL) carriers, which do not have an associated DL. A cell or carrier can be configured using a time slot or subframe format consisting of DL and UL symbols, and the cell or carrier is considered to be operating in time division duplex (TDD) mode. Typically, for unpaired spectrum, the cell or carrier operates in TDD mode, while for paired spectrum, the cell or carrier operates in frequency division duplex (FDD) mode. Access nodes can provide wireless access according to one or more wireless communication protocols, such as Long Term Evolution (LTE), LTE Advanced (LTE-A), 5G, 5G LTE, 5G NR, High Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. Although it is understood that a communication system can employ multiple access nodes capable of communicating with multiple UEs, for simplicity, only one access node and two UEs are shown.

[0095] Figure 2 An exemplary communication system 200 is illustrated, and mathematical expressions for signals transmitted in the communication system 200 are provided. The communication system 200 includes an access node 205 that communicates with a UE 210. Figure 2As shown, access node 205 uses a transmit filter v, and UE 210 uses a receive filter w. Both access node 205 and UE 210 use linear precoding or combination. Assume the channel matrix (or channel model or channel response) H is the N of a multiple-input multiple-output (MIMO) system. rx x N tx A matrix, that is, there exists N tx One transmission antenna and N rx One receiving antenna. N tx A transmission filter v of dimension Ns enables the transmitter to precode or beamform the transmitted signal, where Ns is the number of layers, ports, streams, symbols, pilots, messages, data, or known sequences transmitted. The receive filter w of a multi-antenna system is N... rx x Ns dimensional, and represents a combination matrix, which is usually based on w H y is applied to the received signal y. The above description refers to the transmission from access node 205 to UE210, i.e., DL transmission. Transmission can also occur in the opposite direction (i.e., UL transmission), and in the case of TDD, the channel matrix becomes H. H (where H) H (W is the Hermitian of channel mode H). w can be regarded as a transmission filter, and v can be regarded as a receiver filter. The w used for transmission and the w used for reception can be the same or different; the same goes for v.

[0096] The DL (or forward) channel 215 between access node 205 and UE 210 has a channel model or response H, while the UL (or reverse, or inverse) channel 220 between UE 210 and access node 205 has a channel model or response H. H (Another convention is that UL channels are represented as H...) T H T It is a shift in the channel model H). Although Figure 2 Only one access node and one UE are described, but the communication system 200 is not limited to this. On different time-frequency resources (e.g., in a frequency division multiplexed-time division multiplexed (FDM-TDM) communication system, as in a typical cellular system) or on the same time-frequency resources (e.g., in a multi-user MIMO (MU-MIMO) communication system, where multiple UEs are paired and transmissions to each UE are precoded individually), the access node can serve multiple UEs. In paired UEs, intra-cell interference exists.

[0097] Furthermore, multiple access nodes can exist in the network. Some of these access nodes can collaboratively serve UE 210 using methods such as joint transmission (e.g., coherent joint transmission, non-coherent joint transmission, coordinated multipoint transmission, etc.) and dynamic point-to-point handover. Other access nodes may not serve UE 210, and their transmissions to their own UEs may cause inter-cell interference to UE 210. The scenario of multiple access nodes and multiple UEs (where access nodes collaboratively serve UEs and MU-MIMO is present as an exemplary scenario in this paper.)

[0098] One way to increase network resources is to utilize the growing availability of spectrum, including not only licensed spectrum resources of the same type as macro cells, but also licensed spectrum resources of different types (e.g., macro cells are FDD cells, but small cells can use both FDD and TDD carriers), as well as unlicensed spectrum resources and shared licensed spectrum; some of these spectrum resources may be located in high-frequency bands (e.g., 6 GHz to 60 GHz). Unlicensed spectrum is generally available to any user, but must comply with regulations. Shared licensed spectrum may also not be operator-dedicated. Traditionally, cellular networks do not use unlicensed spectrum because it is often difficult to ensure compliance with quality of service (QoS) requirements. Networks operating on unlicensed spectrum primarily include wireless local area networks (WLANs), such as Wi-Fi networks. Cellular operators may consider using unlicensed spectrum due to its typically scarce and expensive nature. It should be noted that TDD is typically used in high-frequency bands and unlicensed / shared licensed bands, thus allowing for communication through channel reciprocity.

[0099] On unlicensed spectrum, there is typically no pre-coordination among multiple nodes operating on the same frequency resources. Therefore, a contention-based protocol (CBP) can be used. According to Section 90.7 of Part 90 (Section 58) of the Federal Communications Commission (FCC), CBP is defined as:

[0100] "A protocol that allows multiple users to share the same spectrum by defining the events that must occur when two or more transmitters attempt to access the same channel simultaneously and establishing rules for transmitters to provide reasonable operating opportunities for other transmitters. Such a protocol may include procedures for initiating new transmissions, procedures for determining the channel status (available or unavailable), and procedures for managing retransmissions when the channel is busy."

[0101] It should be noted that the state of a busy channel can also be referred to as a channel unavailable, a channel not idle, or a channel occupied, and the state of an idle channel can also be referred to as a channel available, a channel idle, or a channel not occupied.

[0102] One of the most common CBP protocols is the "listen before talk" (LBT) procedure in IEEE 802.11 or Wi-Fi (e.g., found in IEEE standard 802.11-2007, "Wireless LAN Media Access Control (MAC) and Physical Layer (PHY) Specifications" (a revision of IEEE standard 802.11-1999, the entire contents of which are incorporated herein by reference). LBT is also known as the carrier sense multiple access with collision avoidance (CSMA / CA) protocol. Under CSMA / CA, carrier sensing occurs before any transmission attempt, and transmission only occurs if the carrier is found to be idle; otherwise, if the carrier is busy, a random backoff time is applied for the next sensing. Carrier sensing is typically performed through a CCA procedure to determine if the power within the channel is below a given threshold.

[0103] ETSI EN 301 893 V1.7.1 (the entire contents of which are incorporated herein by reference), clause 4.9.2 describes two (2) types of adaptive devices: frame-based devices and payload-based devices, which contain the following provisions (incorporated from clause 4.9.2 of ETSI EN 301 893 V1.7.1).

[0104] "Frame-based devices should meet the following requirements:"

[0105] 1) Before initiating transmission on the operating channel, the device should perform a Clear Channel Assessment (CCA) check using "Energy Detection". The device should observe the operating channel for the duration of the CCA observation time, which should be no less than 20 μs. The CCA observation time used by the device should be stated by the manufacturer. If the energy level in the channel exceeds the threshold corresponding to the power level given in point 5 below, the operating channel is considered occupied. If the device finds the operating channel to be idle, it can immediately proceed with transmission (see point 3 below).

[0106] 2) If the device detects that the operating channel is occupied, it should not transmit on that channel during the next fixed frame period.

[0107] Note 1: The device is permitted to continue transmitting short control signaling on this channel, provided that it complies with the requirements of Clause 4.9.2.3.

[0108] Note 2: For devices that transmit simultaneously on multiple (adjacent or non-adjacent) operating channels, the device is allowed to continue transmitting on other operating channels, provided that the CCA check does not detect any signal on those channels.

[0109] 3) The total time a device transmits on a given channel without reassessing the channel's availability is defined as the channel occupancy time. The channel occupancy time should be in the range of 1 ms to 10 ms, and the minimum idle period should be at least 5% of the channel occupancy time used by the device for the current fixed frame period, with a minimum of 100 μs. Near the end of the idle period, the device should perform a new CCA as described in point 1 above.

[0110] 4) When a device correctly receives a data packet destined for it, it may skip the CCA and immediately (see Note 3) continue transmitting management and control frames (e.g., ACK and block ACK frames). Without executing a new CCA, the consecutive sequence of such transmissions by the device should not exceed the maximum channel occupancy time defined in point 3 above.

[0111] Note 3: For multicast, ACK transmissions (associated with the same data packet) from each device are allowed to occur sequentially.

[0112] 5) The CCA power detection threshold should be proportional to the transmitter's maximum transmit power (PH): For a 23 dBm eirp transmitter, the CCA threshold level (TL) should be equal to or lower than -73 dBm / MHz at the receiver input (assuming a 0 dBi receive antenna). For other transmit power levels, the CCA threshold level (TL) should be calculated using the following formula: TL = -73 dBm / MHz + 23 - PH (assuming a 0 dBi receive antenna and PH specified in dBm eirp).

[0113] "Load-based devices" can use "energy detection" to implement LBT-based spectrum sharing mechanisms according to the Clear Channel Assessment (CCA) mode, such as IEEE 802.11. TM Clauses 9 and 17 of IEEE 802.11n [9], and IEEE 802.11n TM-2009

[10] as described in Clauses 9, 11 and 20, but subject to the compliance requirements mentioned in Clause 4.9.3 (see Note 1) (all of these clauses and requirements are incorporated herein by reference).

[0114] Note 1: When such devices are available, it is also desirable to allow a mechanism based on Clear Channel Assessment (CCA) performed using "energy detection," as detailed in IEEE 802.11ac. TM Clauses 8, 9, 10 and 22 of [i.2] (which are incorporated herein by reference).

[0115] Load-based devices that do not use any of the above mechanisms should meet the following minimum set of requirements:

[0116] 1) Before initiating transmission or burst transmission on the operating channel, the device should perform a Clear Channel Assessment (CCA) check using "Energy Detection". The device should observe the operating channel for the duration of the CCA observation time, which should be no less than 20 μs. The CCA observation time used by the device should be stated by the manufacturer. If the energy level in the channel exceeds the threshold corresponding to the power level given in point 5 below, the operating channel is considered occupied. If the device finds the channel to be idle, it can immediately proceed with transmission (see point 3 below).

[0117] 2) If the device detects that the operating channel is occupied, it should not transmit on that channel. The device should perform an extended CCA check, observing the operating channel for a duration equal to the random factor N multiplied by the CCA observation time. N defines the number of idle time slots, resulting in the total idle period to be observed before initiating transmission. Whenever an extended CCA is needed, a value of N should be randomly selected within the range of 1..q, and this value should be stored in a counter. The value of q is selected by the manufacturer within the range of 4..32. This selected value should be declared by the manufacturer (see Clause 5.3.1 q). The counter is decremented whenever a CCA time slot is considered "unoccupied". When the counter reaches 0, the device can transmit.

[0118] Note 2: The device is permitted to continue transmitting short control signaling on this channel, provided that it complies with the requirements of Clause 4.9.2.3.

[0119] Note 3: For devices that transmit simultaneously on multiple (adjacent or non-adjacent) operating channels, the device is allowed to continue transmitting on other operating channels, provided that the CCA check does not detect any signal on those channels.

[0120] 3) The total time the device uses the operating channel, i.e. the maximum channel occupancy time, should be less than (13 / 32) × q ms, where q is defined in point 2 above. After this time, the device should execute the extended CCA described in point 2 above.

[0121] 4) When a device correctly receives a data packet destined for it, it may skip the CCA and immediately (see Note 4) continue transmitting management and control frames (e.g., ACK and block ACK frames). Without executing a new CCA, the consecutive sequence of transmissions performed by the device should not exceed the maximum channel occupancy time defined in point 3 above.

[0122] Note 4: For multicast, ACK transmissions (associated with the same data packet) from each device are allowed to occur sequentially.

[0123] 5) The CCA power detection threshold should be proportional to the transmitter's maximum transmit power (PH): For a 23 dBm eirp transmitter, the CCA threshold level (TL) should be equal to or lower than -73 dBm / MHz at the receiver input (assuming a 0 dBi receive antenna). For other transmit power levels, the CCA threshold level (TL) should be calculated using the following formula: TL = -73 dBm / MHz + 23 – PH (assuming a 0 dBi receive antenna and PH specified in dBm eirp).

[0124] The above content is quoted from Clause 4.9.2 of ETSI EN 301 893 V1.7.1.

[0125] Figure 3A and Figure 3B Block diagrams of conventional systems 300 and 350 for analog beam control and digital beamforming are shown. Figure 3A The system 300 shown includes a baseband assembly 302 for digital processing, multiple RF chain assemblies 304, multiple phase shifters 306, multiple combiners 308, and multiple antennas 310. The system 300 can be used for transmission or reception. For simplicity, Figure 3A The transmission scenario is illustrated as an example; the reception scenario can be understood similarly. Each RF chain 304 receives weighting factors (or weights, p1, ..., p2) from the baseband component 302. m ,like Figure 3A (As shown). The set of weighting factors forms the digital precoding vector, precoding matrix, beamforming vector, or beamforming matrix used for transmission. For example, the precoding vector can be [p1, ..., p... mWhen transmitting multiple layers / streams, baseband component 302 can use a precoding matrix to generate weighting factors, where each column (or row) of the matrix is ​​applied to the transmitted layer / stream. Each RF chain 304 is coupled to multiple phase shifters 306. Theoretically, any phase shift value can be applied to the phase shifters 306, but in practice, typically only a few possible phase shift values ​​are applied, such as 16 or 32 values. Each RF chain 304 generates a narrow beam 312, oriented in a direction determined by the settings on the phase shifters 306 and combiner 308. If any phase shift value can be applied to the phase shifters 306, the beam can be pointed in any direction; however, if only a few phase shift values ​​are available, the beam can be one of several possibilities (e.g., in...). Figure 3A In this diagram, a narrow beam (solid line) is selected by setting a specific phase shift value in RF chain 304. This beam is one of all possible narrow beams (shown by solid and dashed lines, corresponding to all possible phase shift values). Each RF chain selects such a narrow beam, and all such narrow beams selected by all RF chains (RF chains 1-N) are further superimposed. The superposition is based on a digital weighting factor. The weighting factor can make the beam from the RF chain stronger or weaker; therefore, a different set of factors can generate different superpositions in the spatial domain. Figure 3A The image shows a specific beam 314. In other words, different beams 314 can be generated by selecting different digital weighting factors. The digital operations used for beamforming are usually called (digital) beamforming or precoding, while the analog operations used for beamforming are usually called (analog) beam control or phase shifting.

[0126] Figure 3B The system 350 shown is similar to Figure 3A The system 300 shown is connected to each other except that the corresponding combiners 308 in each RF chain 304 are connected to each other.

[0127] An exemplary conventional timing 400 for transmission in frame-based devices Figure 4 As shown. A device (e.g., a unit under test (UUT)) performs a CCA on the channel before transmission, and when the channel is idle (or available, unoccupied), the device transmits during the channel occupancy period and enters an idle state during the idle period. During the idle period, the device performs a CCA to determine if the channel is available.

[0128] Figure 5 The diagram shows a flowchart of an exemplary conventional method 500 for carrier sensing.

[0129] Figure 5 The method 500 shown begins at block 502, where the communication controller receives waveform signals from the UE. In block 504, the communication controller processes the signals and generates decision variables.X The signal processing described in this paper is typically performed in the digital domain, usually at baseband, and may include sampling, analog-to-digital (A / D) conversion, receiver digital combination, and pre-coding weighting. Decision variables. X Used to determine whether the carrier channel is idle or busy. In box 506, the communication controller determines that the decision variable is less than a threshold. T This threshold can be a standardized value or a value derived from a standard or some rule, and can be device-type specific, space-specific, etc. It can also be allowed to change within a specified range based on traffic load, interference conditions, etc. If in box 506, the communication controller determines the decision variables... X The value is less than the threshold T If so, method 500 proceeds to block 508, where the communication controller determines that the carrier channel is idle, and then method 500 ends. If, in block 506, the communication controller determines the decision variables... X The value is not less than the threshold. T If so, method 500 proceeds to box 510, where the communication controller determines that the carrier channel is busy, and then method 500 ends.

[0130] Figure 6 The flowchart of the traditional "listen first, speak later" mechanism 600 is shown. Figure 6 The method 600 shown begins at block 602, where the communication controller assembles frames. In block 604, the communication controller performs carrier sensing, as described above. Figure 5 The described carrier sensing is used to determine if the channel is idle. If, in box 604, the communication controller determines that the channel is not idle but busy, then method 600 proceeds to box 606, where the communication controller stops transmitting frames and waits for a random backoff timer to expire, and then method 600 returns to box 604. If, in box 604, the communication controller determines that the channel is idle, then method 600 proceeds to box 608, where the communication controller transmits frames, and then method 600 terminates.

[0131] Wi-Fi is a prime example of a listen-before-speak mechanism. Wi-Fi uses 802.11 standard technologies, such as the air interface (including the physical (PHY) and MAC layers). In 802.11, stations share a communication channel (or wireless channel) through a mechanism called Distributed Channel Access (DCF) using CSMA / CA. DCF uses physical and virtual carrier sensing (VCS) to determine the state of the medium (i.e., the communication channel). Physical carrier sensing resides in the PHY and uses power detection and preamble detection with frame length delay to determine when the medium is busy. VCS resides in the MAC and uses reservation information carried in the duration field of the MAC header, which declares that the wireless channel is blocked. The VCS mechanism is called the network allocation vector (NAV). A wireless channel is considered idle only when both the physical and VCS mechanisms indicate that the wireless channel is idle. A station with data frames for transmission (e.g., STA1) first performs CCA by listening to the radio channel for a fixed duration (i.e., the DCF inter-frame space, DIFS). If the radio channel is busy, the station waits until the channel becomes idle, delays the DIFS, and then waits for further random backoff periods (by setting a backoff timer with an integer number of time slots). For each idle time slot, the backoff timer is decremented by 1, and when busy is detected, the backoff timer freezes. When the backoff timer reaches 0, the station begins data transmission. Figure 7 The image shows the Wi-Fi channel access process 700 as described above.

[0132] To meet regulatory requirements for operating in unlicensed spectrum and to coexist with other radio access technologies (RATs) such as Wi-Fi, transmissions in unlicensed spectrum cannot be continuous or persistent in time. Instead, on / off mechanisms can be used, or transmissions and measurements can be performed opportunistically on demand.

[0133] Furthermore, for operations typically conducted in high-frequency bands belonging to millimeter-wave systems (especially in the 28 GHz to 60 GHz band), communication exhibits propagation characteristics very different from those in microwave bands (typically below 6 GHz). For example, millimeter waves experience higher path loss over distance than microwaves. Therefore, high-frequency bands are better suited for small-cell operations than macrocell operations, and they typically rely on beamforming using a large number of antennas (e.g., more than 16 antennas, sometimes even hundreds) for efficient transmission. It should be noted that at high frequencies, wavelengths, antenna sizes, and antenna spacing can be smaller than at low frequencies, allowing for a large number of antennas to be equipped on nodes. This results in very narrow beams formed by a large number of antennas, for example, with beamwidths of 10 degrees or even less. This contrasts sharply with conventional wireless communications, where beamwidths are typically much wider, for example, reaching tens of degrees. Figure 8A A schematic diagram of a wider beam pattern 802 using a small number of antennas at low frequencies is shown. Figure 8B A schematic diagram of a narrow beam pattern 804 using a large number of antennas at high frequencies is shown. Narrow beams are generally considered a major new feature of millimeter waves. As a general rule of thumb, the beamforming gain obtained through a large number of MIMOs can be roughly calculated according to... N x K Estimate, of which N K is the number of transmit antennas, and K is the number of receive antennas. This is because the 2-norm of the channel matrix H is roughly based on ( N x K ) 1 / 2 Scaling; therefore, if the precoding vector of the transmission node is P The combined vector of the receiving nodes is w Then the composite channel is w'Hp And through appropriate selection w and p The energy gain of the composite channel can reach N x K This is much higher than when using fewer antennas.

[0134] In unlicensed spectrum, interference is unpredictable. In high-frequency bands such as 60 GHz, directional communication is preferred to mitigate the effects of high path loss. When using directional communication, several specific issues need to be considered, and these issues are exacerbated when using unlicensed high-frequency communication. Some of these issues will be discussed below with examples.

[0135] Directional LBT, which involves listening to the channel using directional beamlines before transmission (e.g., using energy detection (ED)), may miss ongoing directional transmissions; this problem is known as the blind spot problem. The blind spot problem occurs because after a successful LBT, the gNB can transmit to the UE while another transmission is taking place around the UE as the receiver. The blind spot problem is an example of the hidden node problem. Figure 9 A schematic diagram illustrating an example of a blind spot problem is shown. In this example, a gNB can perform a directional LBT on a channel within the ED's listening range 910 to communicate with the UE. Another gNB (referred to as a directional jammer to the gNB) can perform a directional transmission to the UE within the spatial range 920 on the same channel. However, unless the gNB's directional LBT is directed towards the directional jammer's directional transmission, the gNB can hear the channel as idle. The gNB hears the channel is idle and transmits to the UE. However, for the UE, the channel is busy because another gNB is transmitting to the UE, and the UE may not be able to receive the transmission from the gNB. This is caused by a gNB blind spot due to the transmission from the directional jammer.

[0136] When using a directional antenna, the interference at the receiver is stronger and more directional (flickering interference) than when using an omnidirectional antenna, making it more difficult to mitigate the interference through coding or lower modulation. In such cases of strong interference, it is preferable to avoid the interference, for example, by avoiding transmission.

[0137] Simply retransmitting immediately may not solve this type of strong interference problem, because interference can persist for some time, for example, from interference sources that do not adhere to any protocol, or from the beginning of a transmission.

[0138] RTS / CTS (Request to Send / Allow to Send Signaling) is a mechanism used in the 802.11 wireless communication protocol to reduce collisions caused by the hidden node problem. In addition to performing CCA at the transmitter, the receiver also uses it to listen for channel availability before occupying the channel for data transmission.

[0139] In cellular networks, network controllers (e.g., gNBs, TRPs, etc.) typically serve multiple UEs within their coverage area. After a successful CCA (Continuous Access Control) and the network controller occupies a shared spectrum channel, it can transmit the channel / signal to multiple UEs instead of a single UE. Specific feedback from the UEs it serves can help the network controller make better decisions about subsequent data transmission, for example, avoiding transmission to UEs suffering from severe interference, using an appropriate modulation and coding scheme (MCS) level for UEs with relatively low signal-to-interference-noise ratio (SINR) due to interference, or selectively using a shared spectrum channel with less interference. This can be referred to as receiver-assisted channel access in cellular networks.

[0140] To implement this type of receiver-assisted channel access in a cellular network, the following design may be required:

[0141] Measurements specified and performed at the receiver (or UE) include, for example, the number of measurements, the resources used to perform the measurements, quantization criteria, etc.

[0142] The triggering mechanism for the network controller to request the UE to perform measurements and send back a report.

[0143] The UE's reporting mechanism for sending measurement results back to the network controller includes at least control channel resources for sending reports (e.g., channel state information (CSI) reports).

[0144] The network controller considers reports from the UE and performs data channel (and signaling) transmissions. This can be specified or left to the network implementation.

[0145] NR interference measurement

[0146] There are NR schemes available for interference measurement, as specified in TS 38.214 (5.1.4.2). Two types of resources can be used to measure interference in NR:

[0147] Non-zero power (NZP) channel state information reference signal (CSI-RS) resources are used for channel state information measurement and residual interference calculation.

[0148] Channel state information interference measurement (CSI-IM) resources include zero-power resource elements (REs) configured by the network, where interference can be directly measured by the UE.

[0149] In addition to NZP CSI-RS and CSI-IM resources, the standard also defines zero-power (ZP) CSI-RS resources as a set of resource elements in which no physical downlink shared channel (PDSCH) is mapped. However, the UE cannot make any assumptions about the contents of these resources. For example, other signals (besides PDCCH) can be transmitted in those resources from the same gNB, and these signals are mainly used for rate matching.

[0150] Within the same network, by allocating CSI-IM or ZP CSI-RS resources that overlap with NZP CSI-RS resources from other cells, NZP CSI-RS resources can be protected from inter-cell network interference. Transmissions within NZP CSI-RS resources can experience less inter-cell network interference. For ease of explanation, Figure 10 The document provides an example of resource allocation between interfering base stations (gNBs) for interference measurement. Figure 10 Exemplary resources allocated to gNB1, gNB2, and gNB3 are shown, including demodulation-reference signal (DM-RS or DMRS) resources, NZP CSI-RS resources, ZP CSI-RS resources, CSI-IM resources, and resources for data transmission. gNB1, gNB2, and gNB3 are mutually interfering base stations. As shown, the ZP CSI-RS resources allocated to each of gNB1, gNB2, and gNB3 overlap with the NZP CSI-RS resources of the other two. For example, the ZP CSI-RS resources of gNB1 overlap with the NZP CSI-RS resources of gNB2 and gNB3. Similarly, the ZP CSI-RS resources of gNB2 overlap with the NZP CSI-RS resources of gNB3 and gNB1, while the ZP CSI-RS resources of gNB3 overlap with the NZP CSI-RS resources of gNB2 and gNB1. In this way, the NZP CSI-RS resources of each of gNB1, gNB2 and gNB3 are protected from interference from the other two base stations.

[0151] It has been observed that NZP CSI-RS resource allocation is protected through ZP CSI-RS resource allocation in neighboring gNBs, while CSI-IM is unprotected and can be used to directly measure precoding interference from neighboring cells. Figure 10 In the example shown, if the NZP CSI-RS resource allocation is configured as a channel measurement resource (CMR), the UE can use the NZP CSI-RS resource allocation to estimate the channel between the UE and the gNB; or if the NZP CSI-RS resource allocation is configured as an interference measurement resource (IMR), the UE can use the NZP CSI-RS resource allocation to estimate interference from another gNB / TRP. The NZP CSI-RS resource can also be used to measure non-precoded interference after the UE has estimated and removed the transmitted NZP CSI-RS signal. It should be noted that the NZP CSI-RS resource allocation does not guarantee protection against other non-precoded transmissions (e.g., broadcast signals). Figure 10 In the example shown, the CSI-IM resources of a gNB may conflict with pre-coded DL data transmissions (PDSCH) from other gNBs.

[0152] Resources for NZP CSI-RS, ZP CSI-RS, and CSI-IM can be configured separately from the upper layer. Based on time allocation (i.e., the type of resource allocation, such as aperiodic, semi-persistent, and periodic allocation), one or more resource sets can be configured for the UE for the aperiodic, semi-persistent, and periodic time-domain behavior of each of NZP CSI-RS, ZP CSI-RS, and CSI-IM. The upper-layer configuration for NZP CSI-RS includes a reference to the Transmission Configuration Indicator (TCI) state, which indicates the quasi-co-location (QCL) source RS and the QCL type. The RS can be an SS / PBCH block, a tracking reference signal (TRS) (which is a CSI-RS resource set configured with "trs_info" for fine-grained time and frequency tracking), or a CSI-RS located on the same component carrier (CC) / DL BWP or different CC / BWPs.

[0153] In time-domain allocation, a TRS can have two CSI-RS resources in a time slot or four CSI-RS resources in consecutive time slots. The bandwidth of the CSI-RS resources is given by the higher-layer parameter freqBand, and is at least 48 resource blocks (RBs) for unlicensed spectrum (5 GHz). If both NZP CSI-RS and CS-IM are configured for a single CSI report, then NZP CSI-RS and CS-IM are QCL-compliant for “QCL ​​Type D”, as specified in TS 38.214 V16.5.0.

[0154] CSI reports are configured by the upper-level configuration parameter "CSI-ReportConfig" and, depending on the time behavior, can be "aperiodic", "semiPersistentOnPUCCH", "semiPersistentOnPUSCH", or "periodic". The report configuration parameter "reportFreqConfiguration" indicates the reporting granularity in the frequency domain, and the parameter "timeRestrictionForInterferenceMeasurements" can be used to implement time-domain restrictions on interference measurements.

[0155] When two resource settings are configured, one for channel measurement (e.g., SSB or CSI-RS) and the other for interference measurement (e.g., CSI-IM or NZP CSI-RS), the number of SSB or CSI-RS resources used for channel measurement is equal to the number of CSI-IM resources or NZP CSI-RS resources used for interference measurement.

[0156] Two modes are defined for each PRB's CSI-IM resource unit.

[0157] It should be noted that the 3GPP specifications do not define any reports based on ZP CSI-RS. ZP CSI-RS is part of the PDSCH configuration (downlink control information (DCI) formats 1_1, 1_2) and signals the UE not to expect PDSCH transmissions on those ZP CSI-RS resources (time and frequency).

[0158] The CSI report defined in the 3GPP specification may include the following indicators: Rank Indicator (RI), Layer Indicator (LI), Channel Quality Indicator (CQI) - 4 bits, RS Received Power (RSRP) - 7 bits, SINR - 7 bits, Precoder Matrix Indicator (PMI), CSI Resource Indicator (CRI), and SSB Indicator.

[0159] 3GPP TS 38.215 defines the Received Signal Strength Indicator (RSSI) based on the linear average of the total received power (in watts, W) observed only for each OFDM symbol of the configuration, and the bandwidth used in the RSSI measurement corresponds to the channel bandwidth.

[0160] The Cross-Link Interference (CLI) Received Signal Strength Indicator (CLI-RSSI) is defined as the linear average of the total received power (in W) observed only in the configured OFDM symbols and within the configured measurement bandwidth, using only the configured measurement time resources. CLI-RSSI measurements are not defined for shared spectrum because they require time advance compensation.

[0161] The existing NR schemes described above for interference measurement are insufficient for receiver-assisted transmissions in shared spectrum. In shared (unlicensed) spectrum, multiple RATs need to coexist in an uncoordinated environment. The only protection available for transmissions or multiple transmissions is the LBT procedure described above. In other words, in the case of communication in shared spectrum, it is possible that multiple RATs may coexist, and channel access in the shared spectrum may occur in an uncoordinated manner. An LBT procedure may be necessary to reduce interference and provide fairness for channel access. Receiver-assisted schemes suitable for communication in unlicensed spectrum may require consideration of specific requirements.

[0162] The following are some requirements for receiver assistance schemes in unlicensed frequency bands, including:

[0163] The transmitter needs to trigger the LBT process before transmitting to the receiver.

[0164] The receiver needs to inform the transmitter of an assessment of the channel or resources used for receiving from the transmitter (e.g., available / unavailable or interfered / uninterrupted). The receiver needs to perform the assessment of the channel or resources before transmission occurs.

[0165] The assessment of channels / resources needs to be simple, robust, and fast; for example, simple energy detection can be used.

[0166] The receiver may need to estimate energy only in channels or resources (or a subset thereof) dedicated to the next transmission to the receiver.

[0167] In some embodiments, for measurements of receiver-assisted channel access in unlicensed spectrum (i.e., evaluating a channel or resource), the interference level on CSI-IM resources can be measured and reported. Measurements on CSI-IM resources have low measurement complexity and do not require channel estimation or sequence detection. As an example, to meet the requirements listed above, a receiver can evaluate a channel in unlicensed spectrum by performing measurements (e.g., energy detection) on the channel's CSI-IM resources and reporting the results to the transmitter as supplementary information for the transmitter to use in transmissions to the receiver. Measurements on CSI-IM resources have relatively low complexity because they do not require channel estimation or sequence detection.

[0168] The following are several proposed implementation designs for receiver auxiliary channel access in unlicensed spectrum:

[0169] Unlike existing CSI reports (where CSI-IM resources must be paired with NZP CSI-RS or SSB resources for channel measurements), no channel measurement resources are required to evaluate channels or resources in unlicensed spectrum. Therefore, a single resource setting can be configured solely for CSI reporting, specifically for interference measurements. The CSI-IM resource is used for interference measurements.

[0170] Each CSI-IM resource setting in a DL BWP can be identified by a higher-level parameter BWP-id, and all CSI resource settings associated with a CSI reporting setting can have the same DL BWP. Therefore, a CSI resource setting is limited to a single BWP. A CSI resource setting configures one or more CSI-IM resources. For shared spectrum access, it is common for the gNB to attempt to access multiple shared spectrum channels simultaneously. When the CCA successfully accesses multiple shared spectrum channels, the gNB can transmit simultaneously on those channels. The gNB can use wideband carriers to occupy multiple consecutive shared spectrum channels, where a BWP can be configured in the wideband carrier so that all CSI-IM resources use that BWP. The gNB can also use carrier aggregation (i.e., using one carrier for every channel in the shared spectrum channel), thus requiring multiple BWPs for these carriers, and measurement resources will belong to different BWPs.

[0171] It can trigger a receiver (e.g., a UE) to measure and report several CSI-IM resources for different BWP / carriers.

[0172] Transmitters (e.g., gNBs) can be used to request channel assessments from multiple receivers (e.g., UEs) simultaneously, thereby reducing signaling overhead. Furthermore, UEs can use the same CSI-IM resources to measure interference.

[0173] When using directional (beamforming) transmission at high frequencies, channel assessment at each receiver requires the use of the same receive beam (or spatial filter) designed for subsequent data transmission to accurately reflect the actual interference situation for each UE. Information about one or more receive beams (or spatial filters) can be indicated to the receiver (e.g., the UE) via a TCI used for interference measurement. The TCI may include QCL Type D information for the receive beam. The QCL Type D information may also be indicated separately from the TCI.

[0174] Interference measurement or energy detection measurement needs to be defined for CSI-IM resources. It should be noted that interference measurement or energy detection can also be performed at time intervals when neither the transmitter nor the receiver (e.g., gNB and UE) is transmitting.

[0175] Various embodiments of the present invention provide a method for receiver-assisted channel access (CCA) in unlicensed spectrum. In some embodiments, a base station intending to transmit to a UE in unlicensed spectrum may request or trigger the UE to perform receive measurements on resources in the unlicensed spectrum. The UE performs measurements to determine whether the resource is busy (also known as occupied, not idle, or unavailable) or idle (also known as unoccupied, idle, or available) in order to receive transmissions from the base station. The UE may perform measurements on the resource by detecting the energy on the resource and determine whether the resource is busy based on the detected energy and a threshold. For example, the UE may perform CCA to determine the availability of resources for reception. Therefore, the UE performing measurements on the resource can be regarded as listening to the resource. The UE may send a measurement report to the base station, which is called receiver-assisted information. The base station may use the receiver-assisted information to determine whether to transmit to the UE in the resource. The base station may determine to transmit to the UE in the resource when the resource is idle based on the receiver-assisted information, and may postpone transmitting to the UE in the resource when the channel is busy based on the receiver-assisted information. When the resource measured by the UE is busy, this may indicate that there is a transmission to the UE in the resource, and that the transmission will cause interference to the base station's transmission to the UE. Therefore, measuring resources to determine whether a resource is busy can be viewed as measuring the interference of existing transmissions on expected transmissions within that resource. Thus, the measurement performed by the UE can be called an interference measurement (IM). The base station can configure resources for which it performs interference measurements. This resource can be called an IM resource (IM resource, IMR) or a CSI resource. A resource can include one or more resource sets or one or more carriers. A resource set can include one or more resources or resource elements. IM can be performed per resource in a resource set, per resource set, or per carrier. Resources can include time resources, frequency resources, spatial resources, or combinations thereof. As an example, an IM resource can be a CSI-IM resource as described above. The UE's report can be defined as a new type of CSI report, and the measurement can also be called a new CSI measurement. A new CSI measurement can include only interference measurements on one or more IMRs, and a new CSI report can include only the measurement results of one or more IMRs. In the following description, for simplicity, a new CSI report is also referred to as a "CSI report". CSI reports can be measured per resource in a resource set, per subset of a resource set, or per carrier mapping based on configuration.

[0176] As used herein, "measurement resource" may be referred to as "listening resource," "performing interference measurement on a resource," "detecting energy on a resource," or "performing CSI measurement on a resource," unless otherwise specified. As used herein, a UE's report on a measurement may be referred to as a "measurement report," "CSI report," "interference measurement report," "listening report," or "interference measurement indicator (IMI) report." As used herein, the terms "unlicensed spectrum" and "shared spectrum" are used interchangeably.

[0177] The embodiments can be applied to communications between a base station and a UE, as well as between UEs, in unlicensed spectrum. As an example, a base station may have downlink data available to a UE and trigger or request the UE to measure resources for receiving data. As another example, a UE may have uplink data available to a base station, which can then use this data to measure resources for receiving data. In this case, the UE may not need to request or trigger the base station to measure resources when the base station is aware of the uplink transmission schedule. As yet another example, a first UE may have data available to a second UE (e.g., in device-to-device (D2D) communication) and trigger or request the second UE to measure resources for receiving data. For illustrative purposes only, the various embodiments are described below in conjunction with the scenario where a base station requests a UE to perform interference measurements. Those skilled in the art will recognize that many variations, modifications, and substitutions can be applied without departing from the spirit and principles of the invention.

[0178] According to some embodiments, methods, apparatus, and signaling between a base station and a UE are provided, wherein the base station requests the UE to listen for received energy / interference on specific resources of unlicensed spectrum and report it back to the base station. The information reported by the UE can be used for future transmissions to the UE. As an example, a gNB can (e.g., via DCI) send a request to the UE or a group of UEs, requesting the UE or group of UEs to measure the received energy on specified / configured resources, compare the received energy with a threshold, and provide timely feedback on the measurement before data transmission from the gNB to the UE. The UE listens for resources based on the detected energy on those resources, indicating that the resources are busy and the UE does not expect to receive transmissions on those resources. As mentioned above, the specified / configured resources may include one or more carriers, or one or more sets of resources. The UE can be used to detect the received energy on the entire bandwidth of a carrier, a portion of the carrier's bandwidth, specific time resources, frequency resources, spatial resources, etc.

[0179] The relationship between energy and power is well-known, with power measured as energy per unit of time. Therefore, in this invention, the terms "power" and "energy" will be used in conjunction with the above understanding. Energy thresholds are typically defined for a fixed amount of time and are thus equivalent to a specific power. Furthermore, interference measurements and reporting can be performed by measuring power on an associated resource or detecting energy on an associated resource. Therefore, in this invention, the terms "interference measurement and reporting," "power measurement and reporting," and "energy detection and reporting" are used interchangeably, and it is understood that one can be derived proportionally from the other.

[0180] In one embodiment, a new received energy measurement is provided (e.g., CSI-RSSI as defined in 38.215 and configured based on CSI-IM, and CC-RSSI as defined in this invention).

[0181] In one embodiment, a new DCI format (or one or more fields from an existing DCI format) is provided. The new DCI format can be used to inform the UE to measure interference on a set of resources (e.g., resources on an internal carrier or cross-carrier) and report the measurement results back to the gNB via an interference measurement indicator (IMI) map, which indicates available resources (i.e., which resources are available). The IMI map can indicate the interference status of each measured resource. The interference status can indicate whether the resource is available or unavailable, or whether the resource is interfered with or not, etc. The interference status of a resource can be determined by the UE based on the energy measured on the resource and a threshold. For example, if the measured energy is greater than a threshold, the resource can be determined to be idle, and if the measured energy is not greater than a threshold, the resource can be determined to be busy. The IMI map can also be used to indicate the energy detected on each resource. In this case, the gNB receiving the IMI map can determine the interference status of the resource based on the energy detected on the resource and a threshold.

[0182] In one embodiment, a new DCI format is provided to inform a group of UEs to begin interference measurements, wherein the group of UEs can be identified by a group adio network temporary identifier (RNTI) used to scramble the DCI cyclic redundancy check (CRC).

[0183] In one embodiment, a technique is provided for reporting interference measurement results (e.g., non-periodic, periodic, or semi-static), wherein a configurable number of bits is used to quantify the measurement results.

[0184] In some embodiments, extensions and enhancements to the current CSI feedback mechanism are proposed to allow a group of UEs (where UE-specific, group-based, or broadcast triggers can be used) to measure their interference conditions / states (or energy sensing results) and report them back to the gNB. In the conventional case of CSI feedback, the gNB considers these reports from a group of UEs and performs further data transmission for each implementation. The gNB behavior can be defined in the standard specification. Furthermore, instead of introducing RTS / CTS (or transmit request (TR) and transmit accept (TA) / transmit delay (TD)), rapid reporting of energy sensing is defined (e.g., a new type of CSI, as supplementary information for the UE (receiver)).

[0185] To achieve faster reporting, shorter processing times are needed, especially for reporting new CSI measurements (or IMs) in the implementation. Defining simpler measurements and reporting will help reduce processing time. If the UE only needs to perform energy detection (without processing RS via channel estimation or sequence detection, etc.), then the measurement should be fast, at least for some steps. It should be noted that if the UE CSI report is simply defined as receiver auxiliary information, very fast reporting may not be critical.

[0186] The embodiments provided in this invention also include the following aspects:

[0187] Transmitting CSI requests / triggers within DCI. CSI requests within DCI have traditionally been supported. A CSI request can be the status of a codeword in a request field, and no new field needs to be introduced. Group DCIs that trigger a group of UEs can be used, and one motivation is that the gNB may need to trigger multiple UEs simultaneously and report the same type of CSI using the same measurement resources (e.g., IMR or CSI-IM resources). Within a group DCI, indications or configurations of PUCCH resources, spatial QCLs, etc., may be required for each UE.

[0188] Define new measurements and CSI reports, for example, for energy detection or interference measurements. Define the granularity of reporting within quantization and frequency resource units.

[0189] The UE sends a CSI report about the indicated / configured PUCCH resources. The CSI report can also be carried on data transmission (e.g., on PUSCH).

[0190] In addition to energy detection on IMR or CSI-IM resources, the UE can also perform a CCA-like process on several energy detection or listening resources to derive the reporting volume.

[0191] Possible gNB behaviors can be specified after receiving one or more CSI reports.

[0192] Measurement

[0193] In some embodiments, two types of measurements that the UE can be requested to perform may be provided.

[0194] The first type of measurement performed by the UE can include measuring the linear average of the total received power (in W) observed only in the OFDM symbols of the measurement time resource across the entire carrier bandwidth (referred to as component carrier (CC)-RSSI). The UE can be requested to measure CC-RSSI in one or more carriers (cross-carriers). This type of measurement can be used in conjunction with procedures such as LBT. If the gNB and the UE are not transmitting in the associated OFDM symbol where the measurement is performed, this type of measurement can reflect interference conditions. The first type of measurement essentially measures all power (or energy) received during the duration of the OFDM symbol and across the entire carrier bandwidth, without distinguishing the contribution of power (or energy) to the channel / signal transmitted by the serving gNB (or other UEs serving the gNB). Therefore, an interval is required (or configured) for performing the measurement. For example, if interference measurement resources or CSI-IM resources are configured, they can be configured to occupy all subcarriers of the carrier or one or more OFDM symbols of the BWP. The measurement time granularity is then measured in OFDM symbols, which vary with the sub-carrier spacing (SCS) of the carrier (e.g., 480 kHz or 960 kHz). In another example, if measurement intervals are used, measurements can be performed similarly to CCA energy sensing; in CCA energy sensing, the sensing slots are time intervals such as 5 μs or 9 μs, and are independent of the carrier's SCS.

[0195] In some embodiments, the carriers specified by the gNB for measurement can be wideband carriers (two or more adjacent carriers) or carrier aggregation (two or more carriers, where at least two carriers may not be adjacent). Carrier combinations can be specified via bitmaps or indicators in the DCI. The gNB can specify different energy detection thresholds for each carrier, which the UE uses to report interference measured via IMI mapping. The gNB can specify the measurement duration (interval) for measurements on the carriers. The measurement duration can be associated with (or derived from) an LBT type; the LBT type can be different for each carrier. For example, the interval for measuring carriers can be specified as a duration, rather than the number of symbols or slots that can be selected via indicators provided in the DCI. In one embodiment, the interval duration for measurement is sent via an indicator of the associated LBT type provided in the DCI.

[0196] In one embodiment, the gNB can collect cross-carrier interference indications from multiple UEs (individually or as a group of UEs) and use the collected information to select resources for the next channel occupancy time (COT).

[0197] The second type of measurement generates a CSI Received Signal Strength Indicator (CSI-RSSI) based on the linear average of the total received power (in W) observed only in the OFDM symbols of the measurement time resource and over the measurement bandwidth. The measurement bandwidth can include N resource blocks from various sources, including, for example, co-channel serving and non-serving cells, adjacent channel interference, thermal noise, etc. The measurement time resource used for CSI-RSSI corresponds to the OFDM symbols containing the configured CSI-RS timing as specified in TS 38.215. An example of this type of measurement is CSI-RSSI on the CSI-IM resource used for interference measurement. This type of measurement can reflect interference conditions if the gNB and UE do not transmit in the associated OFDM symbols where an interval is required (or configured) for the measurement. This type of measurement appears unsuitable if no NZP CSI-RS resource is associated with the CSI report.

[0198] In the case of CSI reports used for interference measurements on CSI-IM resources, measurements are performed in the OFDM symbol of the CSI-IM resource and on the resource element (RE) of the CSI-IM resource. The measurement can be defined as the linear average of the power contribution (in watts) of the resource element of the CSI-IM resource (or other types of IMR resources). When a signal is assigned to a UE for reception on a CSI-IM resource, the measurement can also be defined as the linear average of the noise and interference power contributions (in watts) of the resource element of the CSI-IM resource (or other types of IMR resources). This is determined by radio resource control (RRC) parameters. freqBand Within each configured physical resource block (PRB), CSI-IM resources can be used for a mode with one OFDM symbol occupying four consecutive REs in the frequency domain (therefore, 4x1 in both the frequency and time domains), or a mode with two consecutive OFDM symbols occupying two consecutive REs in both the frequency and time domains (therefore, 2x2 in both the frequency and time domains). Therefore, the measurement granularity in the time domain is either one OFDM symbol or two OFDM symbols.

[0199] According to 3GPP TS 38.331 V16.4.1, a single resource setting can be configured for the CSI report, and the resource setting (e.g., determined by higher-level parameters) csi-IM-ResourcesForInterference (Given) for interference measurements to provide a CSI report. The CSI report in various embodiments may be an L1 interference measurement (L1-IM) report (e.g., indicating whether interference (measured energy, or received energy) on a channel or resource is above a threshold for energy detection), an L1 energy detection (L1-ED) report (e.g., indicating the energy measured on a channel or resource), or an L1 channel sensing (L1-CS) report (e.g., indicating whether a channel or resource is available). Hereinafter, such a CSI report will be referred to as an L1-IM report without loss of generality in the following description. An L1-IM report may be any of the L1-IM, L1-ED, or L1-CS reports described above. An L1-IM report includes the energy measured in the configured resources of the channel and may include a specific spatial orientation. An L1-IM report may indicate the interference level or whether the channel is available in the configured resources. An L1-IM report may also include other reporting quantities, such as RI, CQI, RSRP, SINR, CRI, SSBRI, etc.

[0200] Each CSI resource setting CSI-ResourceConfig Configurations may include a list of S ≥ 1 CSI resource sets (e.g., determined by higher-level parameters). csi-RS-ResourceSetList (Given), where the list may include references to one or both of the NZP CSI-RS resource set and the SS / PBCH block group, or the list may include references to the CSI-IM resource set. Each CSI resource setting may be located in a higher-level parameter... BWP-id The identified DL BWP, and all CSI resource settings associated with the CSI reporting settings, have the same DL BWP. According to Section 5.2.1.1 of TS 31.214 V16.5.0, each CSI reporting setting... CSI-ReportConfig With a single downlink BWP (by higher layer parameters) BWP-Id (Indication) associated with (in the context of channel measurement) CSI-ResourceConfig (as given in the document), and includes the following parameters for a CSI reporting band: codebook configuration, including codebook subset restrictions, time-domain behavior, frequency granularity for CQI and PMI, measurement restriction configuration, and CSI-related quantities to be reported by the UE, such as layer indicator (LI), L1-RSRP, L1-SINR, CRI, and SSB Resource Indicator (SSBRI).

[0201] According to 3GPP TS 38.331 V16.4.1, the temporal behavior of CSI-RS resources in CSI resource settings can be determined by higher-level parameters. resourceType This indicates the periodicity and can be set to non-periodic, periodic, or semi-persistent. For periodic and semi-persistent CSI resource settings, the number of configured CSI-RS resource sets is limited to S = 1. For periodic and semi-persistent CSI resource settings, the configured period and slot offset can be given in the associated DL BWP system parameters, such as... BWP-id The given 。 When the UE is configured with multiple CSI-ResourceConfig When (including the same NZP CSI-RS resource ID), the same time-domain behavior applies. CSI-ResourceConfig When a UE is configured with multiple UEs that include the same CSI-IM resource ID... CSI-ResourceConfig The same temporal behavior is applied to CSI-ResourceConfig. All CSI resource settings associated with CSI reporting settings should have the same time-domain behavior.

[0202] In one embodiment, the CSI-IM for periodic or semi-persistent resource allocation may not be averaged over multiple periods, and the energy in each CSI-IM resource set may be measured individually and compared with an energy threshold. Interference measurement indicator (IMI) reports (e.g., PUCCH IMI reports) may be generated after each measurement or period, or may cover multiple CSI-IM repetitions (i.e., multiple repetitions of CSI-IM). An IMI report may include measurement results for one or more resources used for the measurement. An IMI report may include an IMI indicating the measurement results for a resource or resource set. An IMI may be a 1-bit value indicating the interference state on a resource. For example, the interference state is determined based on energy detection on the resource, and can indicate whether the resource is busy or idle based on the energy detection and a threshold. Therefore, an IMI can also be understood as an indicator indicating whether a resource is busy or idle. As an example, an IMI corresponding to a resource may have values ​​1 and 0: value 1 indicates the resource is available, and value 0 indicates the resource is unavailable. As another example, value 0 may be used to indicate an available resource, while value 1 may be used to indicate an unavailable resource. An IMI report may include multiple IMIs (which may be referred to as IMI maps) corresponding to multiple resources. If the PUCCH IMI report covers multiple CSI-IM repetitions on a resource, the corresponding IMI can be set to 1 if all CSI-IMs performed on the resource have low-interference (or available) results (indicating that the resource is available in this example); or the corresponding IMI can be set to 1 if the minimum number of CSI-IM repetitions performed on the resource have low-interference (or available) results. In one embodiment, the condition of setting an IMI to 1 may correspond to a low-interference pattern of multiple CSI-IMs. The condition is satisfied when the pattern is found. For example, the pattern can be defined as follows: in k + p CSI-IM repetitions, m of the first k CSI-IM repetitions must have low-interference, and n of the last p repetitions must have low-interference, where k, p, m, and n are integers.

[0203] The UE can measure interference within the CSI-IM resource set and compare the measurement results with an energy detection (ED) threshold. The UE can detect the received energy within the CSI-IM resource set. The ED threshold can be provided through higher-layer configuration and is associated with the bandwidth coverage of the CSI-IM resource set. For example, if the ED threshold for the entire carrier bandwidth or bandwidth part (BWP) is ED, and the CSI-IM resource set represents x% of the entire carrier bandwidth or BWP, then the ED threshold corresponding to the measured IMI report in the CSI-IM resource could be x% of ED.

[0204] The goal is to allocate CSI-IM resource sets for the corresponding CSI-IM in both the time and frequency domains, providing sufficient interference information for the allocated resources that can be used for future transmissions.

[0205] In one embodiment, the gNB may indicate the number of periodic CSI-IM resources corresponding to a time interval, or the gNB may directly indicate the time interval during which the UE must measure interference and report IMI. The time interval may correspond to an LBT type. As used herein, the time interval is the time interval during which the gNB does not transmit power on the specified CSI-IM resources. The UE may perform measurements on the CSI-IM resources (e.g., in the frequency domain) during the time interval.

[0206] The CSI-IM resources configured for L1-IM reporting can be shared among multiple UEs to perform their respective measurements. These UEs can share CSI-IM resources for interference measurements because no specific signal is indicated to the UE for processing (e.g., for channel estimation or signal detection). UEs typically behave identically on CSI-IM resources.

[0207] However, in the case of frequency range 2 (FR2) communication or when beamforming is performed, the UE will use a receive beam or spatial filter to receive its downlink signals or channels. The receive beam varies from UE to UE and can change over time. After a beam management process between the gNB and UE via the transmission of downlink signals (e.g., SS / BCH and / or CSI-RS) and uplink reports (e.g., L1-RSRP / L1-SINR and downlink signal index), the gNB can obtain the necessary information for beamforming for downlink transmission. For example, through the TCI state, the gNB can also configure and indicate to the UE the DM-RS port of the PDCCH or the CSI-RS port of the CSI-RS resource; the TCI state includes parameters for configuring the quasi-co-location (QCL) relationship between one or two downlink reference signals of the PDSCH and the DM-RS port. By configuring and indicating the QCL relationship to the UE, the UE can appropriately set the receive beam or spatial filter.

[0208] In the case of L1-IM reporting, it may be necessary to indicate the TCI status and therefore QCL information to the UE for interference measurement, as the interference measurement should reflect the interference situation when the UE receives downlink channels or signals sent to the UE. For reference signals, such as NZP CSI-RS for channel measurement, their associated TCI status and therefore QCL relationship can be explicitly configured. When CSI-IM is performed together with NZP CSI-RS measurements for CSI reporting (e.g., reporting channel quality indicator (CQI)), the CSI-IM resources for interference measurement can be based on the TCI status and QCL of the associated NZP CSI-RS resources used for NZP CSI-RS. Therefore, in this case, TCI status or QCL information is not explicitly configured for CSI-IM. In another case, for L1-IM reporting, when no NZP CSI-RS or other signals are used for measurement with CSI-IMR, the TCI status or QCL information for CSI-IM can be derived from these signals. In this scenario, explicit indication of the TCI status or QCL information used for CSI-IM can be used for CSI-IM resources, as in the case of NZP CSI-RS resources. However, relying solely on the TCI status or QCL information configured by RRC may not be sufficient to handle the time-varying beamforming characteristics of downlink transmissions, or may prevent different UEs from sharing the same CSI-IM resources for interference measurements. In one example, the TCI indication field (also referred to as the TCI field for simplicity) can be used in the DCI that triggers L1-IM reporting, where the TCI indication field explicitly indicates the TCI status and QCL information used for interference measurements.

[0209] As an example, when the UE-specific DCI format used for scheduling downlink transmissions is used to trigger L1-IM reports, the TCI field (in the UE-specific DCI format) indicating the TCI status and QCL information of the PDSCH transmission can also indicate the TCI status and QCL information of L1-IM, as well as the report triggered on the associated measurement resource. As another example, the TCI status and QCL information configured for the DCI control resource set (CORESET) can be used for L1-IM and reports triggered on the associated measurement resources.

[0210] When using group DCI to trigger L1-IM reports from multiple UEs, a TCI field is required to indicate to each UE the TCI state and QCL information (e.g., at least "QCL Type D") for the UE to perform interference measurements on the associated interference measurement resources. Multiple candidate TCI states (and QCL information) can be configured for each UE, and the TCI field indicates the one selected from the candidate TCI states.

[0211] In addition to the space RX parameter (i.e., "QCL type D"), QCL information may also include:

[0212] "QCL Type A": {Doppler shift, Doppler spread, average delay, delay spread}

[0213] "QCL Type B": {Doppler shift, Doppler spread}

[0214] "QCL Type C": {Doppler shift, average delay}.

[0215] For interference measurement, spatial RX parameters (i.e., QCL type D) are required. Other QCL information, such as QCL type A, QCL type B, or QCL type C, may not be strictly necessary because channel estimation of the measurement resources may not be required. Therefore, for a TCI state dedicated to CSI-IM, only "QCL type D" can be configured. In cases where the TCI state is shared or reused for other channel / signal reception, one of QCL types A, B, and C can be configured in addition to "QCL type D," and the UE can use the corresponding QCL information (e.g., average delay) for interference measurement. In one embodiment, a new QCL type can be introduced to include only the QCL information required for interference measurement (in addition to "QCL type D"). For example, "QCL type E" can be defined to include at least the average delay.

[0216] To report supplementary information to aid gNB transmission decisions following CCA, other types of measurements and reports can be considered, such as CQI reports or SINR reports, both of which can be referred to as CSI reports. These CSI reports reflect channel and interference conditions, thus providing a better picture of the overall situation at the receiver. In this case, in addition to interference measurement resources such as CSI-IM resources, channel measurement resources (CMR) will also be needed for these CSI reports. If multiple UEs are triggered for these CSI reports, each UE will need to trigger and transmit a CMR, and the overhead can be significantly higher.

[0217] When the UE receives a DCI instructing the UE to perform L1-IM on a specified / configured resource, the UE can begin measuring the received energy on the specified resource (e.g., multiple resource blocks or multiple carriers) within the duration of the OFDM symbol of the measurement time resource. In one embodiment, the intra-carrier resource can be represented by a CSI-IM resource, and the cross-carrier resource can be a carrier resource or a CSI-IM resource on multiple carriers.

[0218] The frequency resources and OFDM symbols used for interference measurement can be configured by the upper layer (e.g., via RRC configuration). Interference measurements can be performed on time resources in various ways. In one embodiment, the UE can measure the energy (i.e., interference) of a specific pattern in the frequency and time domains for multiple instances of CSI-IM. In another embodiment, the UE can measure the interference (energy) received on a specified resource for a consecutive number of symbols, time slots, or subframes.

[0219] After completing the measurement, the UE can report back to the base station via PUCCH resources (frequency and time), which can be configured by a higher layer (e.g., by RRC).

[0220] In some embodiments, in its report, the UE can indicate the observed interference level for each measured resource or carrier using an interference measurement indicator (IMI) mapping, where the interference level can be quantified using bits. In one embodiment, the UE can feed back one bit per resource or carrier, and therefore for measurements on multiple resources, the IMI mapping can be multiple bits. For example, a PRB (12 subcarriers) in an OFDM symbol can be used for the IM. The UE feedback bit corresponds to each of the 12 subcarriers. If the resource or carrier is detected as idle (i.e., with low interference), the bit can be set to 1; otherwise, if the resource or carrier is detected as busy, the bit is set to 0. In one example, the UE can use an energy threshold to compare the received energy on a resource (e.g., a time-frequency resource). If the received energy is less than the energy threshold, the bit corresponding to the resource can be set to 1. The energy threshold can be configured by a higher layer. In another example, the feedback bit can be set if a minimum condition is met. For example, the feedback bit can be set to 1 when the energy detected by a minimum number of resource sets (e.g., a CSI-IM resource set (a portion of the CSI-IM resource set)) is less than an energy threshold. In another example, the UE can feed back a single bit corresponding to all configured resources (e.g., one or more configured resource sets). The IMI map can include one or more entries, and each entry is a bit. Each entry in the IMI map can correspond to a resource, a resource element, multiple resources (or resource elements), or a resource set.

[0221] In one embodiment, the UE may use a spatial RX filter to perform interference measurements. Information about the spatial RX filter can be provided in the TCI field included in the DCI. For example, each resource in the resource set to be measured may have a corresponding orientation, and the receiver may need to measure interference in that particular orientation (in both frequency and time) within that particular resource. Resources configured for the IM may include time resources, frequency resources, spatial resources, or combinations thereof.

[0222] A UE can belong to one or more UE groups configured by higher-layer signaling (e.g., RRC signaling). A DCI can address a group of UEs. When a DCI addresses a group of UEs, the DCI's CRC can be scrambled using a group-specific RNTI. When a UE receives a DCI, it can blindly decode the DCI using its available RNTI codes. If a group RNTI is identified, the UE can use the associated configuration parameters of the UE group associated with that group RNTI.

[0223] The energy threshold used by the UE to report IMI can be configured by a higher layer. For cross-carrier scenarios, the energy threshold can be configured for the total energy of each carrier; or for intra-carrier scenarios, the energy threshold can be configured for the energy of each CSI-IM resource. The value of the energy threshold can be selected based on regulatory requirements (e.g., LBT requirements) or the acceptable interference received power based on a specific transmission modulation and coding scheme (MCS).

[0224] The signaling used to implement the proposed scheme may include a DCI carrying a trigger indication for a UE or a group of UEs, and a PUCCH report from the UE performing interference detection (e.g., via IMI mapping). For example, the PUCCH report may be L1-IM. In one embodiment, the DCI signaling may be implemented by extending an existing DCI format with new fields or by using a new DCI format.

[0225] In one embodiment, the DCI format X_Y can be used to trigger an L1-IM report for a group of UEs, where "X_Y" is a placeholder for a format name that has not yet been specified. As used herein, a DCI with the DCI format X_Y will be referred to as DCI X_Y. DCI X_Y carries a CRC scrambled with an RNTI value, which is used by the group of UEs intending to receive the DCI. A set of bits (and fields) can be allocated or configured within DCI X_Y for information sent to the UEs.

[0226] In one embodiment, for the UE, DCI X_Y may include a field for TCI, which may be a TCI indicator for a higher-layer parameter indicating the RS index for QCL type D corresponding to the TCI state. In another embodiment, DCI X_Y may also provide other types of QCL. If the field is not present in DCI X_Y, the UE can be configured via a higher layer having a corresponding TCI state for IM.

[0227] In one embodiment, for the UE, DCI X_Y may include a field for IM triggering (also known as the IM trigger field) to request the UE to perform an L1-IM report. The IM trigger field may simply indicate whether an L1-IM report is requested from the UE. The associated interference measurement resources (e.g., CSI-IM resources) and their trigger timing offsets can be configured by RRC signaling. Measurement resources may be available aperiodically or periodically and configured via periodic CSI-IM resource sets. CSI-IM resource sets can be configured by upper-layer parameters, whereby the UE is requested to measure interference against the CSI-IM resource set and report L1-IM. A CSI-IM resource set may include one or more carriers (cross-carriers) or a resource set within the same carrier. A CSI-IM resource set is a resource that does not carry transmissions from the gNB during a measurement interval or measurement instance. The pattern and time period of the CSI-IM resource set can be defined such that UE measurements are reliable and cover the expected resources for DL ​​transmissions requiring interference measurements.

[0228] If the DCI is scrambled using the UE group RNTI, then all UEs belonging to the same group can measure and report on the same CSI-IM resource set.

[0229] To reduce signaling overhead or DCI size, in one embodiment, the IM trigger field can be a common field for all UEs detecting DCI X_Y, where DCI X_Y carries an associated RNTI value for CRC scrambling. In this embodiment, UEs can be triggered simultaneously for L1-IM reports. Interference measurement resources (e.g., CSI-IM resources) can be used to associate with a group of DCI_X_Ys with the associated RNTI values.

[0230] It should be noted that multiple parameters used for interference measurement can be configured by higher layers via RRC. However, in some embodiments, one or more of these parameters may optionally be provided via DCI. In one embodiment, if one or more parameters are included in the DCI, they take precedence over higher-layer configuration. Exemplary parameters that may optionally be included in the DCI are described below, including the CSI-IM time-domain indicator, IM ED threshold, period and offset, and IMI bit length. The DCI may include any one or more of these parameters.

[0231] The CSI-IM time-domain indicator can identify entries in higher-level parameters that specify the CSI-IM configuration used for measuring interference. For the UE in DCI, a field for this parameter may exist to indicate the trigger timing offset (i.e., the time between receiving the triggered DCI and transmitting the triggered CSI-IM report).

[0232] The IM ED threshold determines the energy threshold to be used for each resource determined by IMI. For L1-IM, the IM ED threshold can be derived from the CCA ED threshold specified by the spectrum conditioner. When the interference measurement resource or CSI-IM resource occupies the entire shared spectrum channel, the IM ED threshold can be the same as the CCA ED threshold.

[0233] The period and offset can be used to indicate a single (one-off) report associated with an instance of CSI-IM and L1-IM reporting, or to activate multiple instances of CSI-IM and L1-IM reporting with a specific periodicity. The UE can perform L1-IM and report it in each period. The CSI-IM resource set can have the same period and offset as the PUCCH L1-IM report.

[0234] The IMI bit length indicates the number of bits used to encode the interference measurement results for each resource (or resource element) in the CSI-IM resource set. Each resource element has a corresponding IMI that maps the interference measurement results to resource elements in the CSI-IM resource set, where the IMI corresponding to the resource element in the resource set has an associated IMI bit length, i.e., the number of bits used to quantify the corresponding interference level (the measurement result of the corresponding element).

[0235] The DCI may optionally include one or more of the following exemplary parameters for interference statistics measurements: a Channel State Information-Interference Measurement (CSI-IM) time-domain indicator indicating the CSI-IM configuration for interference statistics measurements; a period and offset parameter indicating the period and timing offset for interference statistics measurements and reporting; and a statistics type parameter indicating the interference type statistics for each resource that the UE will report. Interference type statistics may include the following values ​​or any combination thereof within the measurement duration period: average channel idle duration, standard deviation of channel idle duration, average channel busy duration, longest channel idle duration, shortest channel idle duration, longest channel busy duration, and shortest channel busy duration.

[0236] The UE used for interference statistics measurements can report the measured interference statistics, which can be included in the interference measurement report (e.g., L1-IM report) sent by the UE to the gNB. The report may include an interference statistics measurement indicator (STA-IMI) that indicates the statistics of the measurement results for a resource or a subset of resources. The statistics may include the following values ​​or any combination thereof within the measurement duration period: average channel idle duration, standard deviation of channel idle duration, average channel busy duration, longest channel idle duration, shortest channel idle duration, longest channel busy duration, and shortest channel busy duration, as configured by the DCI.

[0237] The following illustrates examples of how the proposed method can be applied to implement CCA-based receiver feedback for one or more carriers. Various embodiments provide methods for receiver-assisted channel access (CCA) in unlicensed spectrum. The UE performs CCA on a measurement resource to determine if the measurement resource is idle. The UE can measure / detect the energy received on the measurement resource and compare the received energy with an ED threshold to generate a measurement result, which can be indicated by an IMI. When the received energy is less than the ED threshold, the measurement resource is determined to be idle, and CCA is determined to have passed (or succeeded); otherwise, when the received energy is not less than the ED threshold, the measurement resource is determined to be busy, and CCA is determined to have failed. In various embodiments, the UE can be used to perform measurements on one or more carriers, which are only used as illustrative examples of measurement resources. Various embodiments can be applied to measuring one or more resource sets, resources of one or more carriers, specific frequency resources, time resources, spatial resources, etc. In various embodiments, a successful CCA means that the CCA conditions are met (e.g., the CC-RSSI or L1-IM for each carrier is less than the ED threshold), and the PUCCH CCA indicator represents the PUCCH IMI for a single carrier. The UE can perform CCA on all or a portion of the carrier bandwidth. In various embodiments, the performed CCA corresponds to the UE measurement requested in DCI X_Y and reported to the gNB. It should be noted that even if the CCA fails (indicated by the gNB), the UE can still send back a report, and the gNB can receive the report because there is no interference at the gNB. This is not the case for the LBT procedure; if the LBT procedure fails, the device performing the LBE procedure must postpone its transmission.

[0238] In unlicensed frequency bands, a Level Bypass (LBT) procedure is required between consecutive transmissions or receptions. Prior to COT, equipment (e.g., gNB) may perform longer LBTs or LBT Category 4, which includes listening to the channel and a backoff period of exponential truncation if the channel is detected to be busy. During COT, shorter deterministic LBTs may be required. Depending on the length of the interval caused by processing and handover time between reception and transmission, LBT procedures may or may not be required for both the gNB and UE during COT.

[0239] In one embodiment, DCI X_Y can specify one or more conditions that need to be met on the receiver side for transmission to the receiver. For example, the gNB can provide the UE with an interference or energy detection threshold, along with a list of resources and their durations for checking each condition, via DCI X_Y. As an example, this condition could require that the average energy of a specified measurement resource (e.g., a carrier) is less than a threshold during the measurement window time interval. However, the same condition can also be configured for the UE from a higher layer (e.g., on a per-carrier basis).

[0240] In various embodiments, the UE performs CCA for interference measurement to determine the interference state of the measurement resource (i.e., the carrier in the embodiments); based on the interference state, the UE provides the gNB with receiver assistance information for downlink transmission. Figure 11A schematic diagram of an embodiment of method 1110 for receiver-assisted channel access in unlicensed spectrum is shown. In this example, the UE feeds back a measurement report indicating an available carrier to the gNB. The gNB can perform CCA on a carrier (channel) in the unlicensed spectrum, for example, when it wants to transmit data to the UE on the carrier. When the CCA passes (step 1102), i.e., when the gNB determines the carrier is available based on the CCA, the gNB can send DCI X_Y to the UE, requesting the UE to perform interference measurement on the carrier (step 1104). The gNB can specify a carrier for the UE so that the UE can perform interference measurement on the specified carrier. Conditions can be specified that can be used to trigger the UE's measurement report and / or determine whether the UE's CCA passes (i.e., the specified carrier is idle). As an example, the condition can require that the energy received on the specified carrier is less than a threshold. In the case of multiple carriers, each carrier can be associated with a corresponding condition (e.g., an energy threshold). After receiving DCI X_Y, the UE can perform CCA on the specified carrier. For example, the UE can measure the energy received on a specified carrier (e.g., a portion of the frequency or the bandwidth of the specified carrier) against a threshold, which can be specified by the gNB or configured by a higher layer. The UE passes CCA (step 1106), i.e., the carrier is determined to be idle, and the UE can send an L1-IM report on the PUCCH including an IMI for the carrier (step 1108). In this example, the IMI corresponds to the carrier. The carrier's IMI can be set to one (1), indicating that the carrier has passed CCA (or the condition is met) and the carrier is available. The gNB receives the carrier's PUCCH IMI and can optionally perform a second CCA to ensure that the carrier is available from the gNB's perspective. When the second CCA passes (step 1110), the gNB can transmit data to the UE on the carrier (step 1112). The gNB can also skip the second CCA and transmit data to the UE upon receiving a PUCCH IMI indicating that the carrier is available. When data transmission is successfully received, the UE can transmit a data confirmation message, such as a hybrid automatic repeat request (HARQ) message, to the gNB to confirm that the data transmission has been received (step 1114).

[0241] The gNB requesting interference measurements can be referred to as the initiator of an IM or IM report. The initiator (i.e., the gNB in ​​this example) can request the UE to perform interference measurements on multiple resources (e.g., multiple carriers). In this case, after receiving measurement reports for multiple resources from the UE, the gNB can continue transmissions on those resources that the UE has confirmed (i.e., determined to be idle). In other words, the UE may not expect to receive transmissions or grants on resources that are found unavailable (due to too much interference according to the UE's measurements). Even if the UE detects that a carrier is busy, the UE can still send a PUCCH IMI report about the carrier (if the gNB instructs it to do so). In another embodiment, the UE may not send a report of detecting an unavailable carrier (channel), and based on this report, the gNB can infer that the resource (carrier) is busy.

[0242] Figure 12 A schematic diagram of another embodiment of method 1200 for receiver-assisted channel access in unlicensed spectrum is shown. In this example, the UE feeds back a measurement report indicating an unavailable carrier to the gNB. Figure 11 Similarly, the gNB can perform CCA on a carrier in unlicensed spectrum, for example, when it wants to transmit data to the UE on the carrier. When the CCA is successful (step 1202), that is, when the gNB determines that the carrier is available based on the CCA, the gNB can send DCI X_Y to the UE, requesting the UE to perform interference measurement on the carrier (step 1204). After receiving DCI X_Y, the UE can perform CCA on the specified carrier. Figure 11 Unlike the previous example, in this case, the UE's CCA fails (step 1206). In other words, the carrier is detected as unavailable according to the UE's CCA. Even if the UE's CCA on the carrier fails, the gNB can still instruct the UE to report the measurement performed on the carrier. Therefore, the UE sends an IM report to the gNB in ​​the PUCCH, which includes the IMI corresponding to the carrier measured by the UE (step 1208). The gNB receives the PUCCH IMI and can optionally perform a second CCA to ensure that the carrier is available from the gNB's perspective. When the second CCA passes (step 1210), the gNB can transmit another DCI X_Y to the UE, requesting the UE to perform another interference measurement on the carrier (step 1212). Upon receiving DCI X_Y, the UE can perform a CCA that succeeds (step 1214) and send the corresponding PUCCH IMI to the gNB (step 1216). The gNB can then transmit data to the UE after performing a successful CCA (step 1218) (step 1220). The UE successfully receives the data and acknowledges that the data has been received (step 1222). Steps 1214, 1216, 1218, 1220, and 1222 are respectively similar to Figure 11Steps 1106, 1108, 1110, 1112, and 1114 are shown, so for simplicity, the details will not be described further in this article.

[0243] In some embodiments, the gNB can trigger periodic reports from a receiver (e.g., a UE). For example, reporting can stop once a minimum number of resources are found to meet CC-RSSI or IM conditions, allowing data transmission to proceed. Figure 13 An example of this situation is shown. Figure 13 A schematic diagram of another embodiment of method 1300 for receiver-assisted channel access in unlicensed spectrum is shown. In this example, the UE periodically reports the measurement results of a carrier to the gNB. The gNB can perform CCA on the carrier (channel) in the unlicensed spectrum, for example, when it wants to transmit data to the UE on the carrier. When the CCA is successful (step 1302), that is, when the gNB determines that the carrier is available based on the CCA, the gNB can send DCI X_Y to the UE, requesting the UE to perform periodic interference measurements on the carrier (step 1304). After receiving DCI X_Y, the UE can periodically perform CCA on the carrier for a period of time (e.g., a measurement window). The UE can perform multiple CCAs on the carrier during the measurement window, some of which may fail (e.g., step 1306), and some of which may succeed (e.g., step 1310). For each CCA performed, the UE can send a PUCCH IMI (i.e., IM report) indicating the CCA result (i.e., the interference measurement result) to the gNB, as shown in steps 1308 and 1312. The PUCCH IMI can indicate whether the carrier is available (CCA passed) or unavailable (CCA failed). When the received IM report (PUCCH IMI) meets the conditions, the gNB can transmit data to the UE on the carrier (step 1314), and the UE can acknowledge that the data transmission has been received (step 1316).

[0244] In some embodiments, the gNB can use the UE to periodically feed back IMI until a successful transmission from the gNB to the UE occurs, such as... Figure 14 As shown. Figure 14A schematic diagram of another embodiment of method 1400 for receiver-assisted channel access in unlicensed spectrum is shown. The gNB can perform CCA on a carrier (channel) in the unlicensed spectrum, for example, when it wants to transmit data to the UE on the carrier. When CCA passes (step 1402), i.e., when the gNB determines the carrier is available based on CCA, the gNB can send DCI X_Y to the UE, requesting the UE to perform interference measurement on the carrier (step 1404). Upon receiving DCI X_Y, the UE can be triggered to perform CCA on the carrier. For example, the UE can measure the received energy on the carrier and compare it with a threshold. As an example, the UE's CCA passes (step 1406), i.e., when the received energy is less than a threshold, the carrier is determined to be available, and the UE can send IMI on the PUCCH to the gNB (step 1408). The IMI indicates that the carrier is available to the UE. The gNB receives the PUCCH IMI and can optionally perform a second CCA to ensure the carrier is available from the gNB's perspective. When the second CCA passes (step 1410), the gNB can transmit data to the UE (step 1412). However, the UE may fail to decode the data transmission (step 1414) and therefore transmit a HARQ negative acknowledgement (NACK) message to the gNB, indicating that the data transmission was not received (step 1416). The UE can then continue to perform another CCA on the carrier in the next cycle configured by the gNB, and this time the CCA may succeed (step 1418). The UE sends an IMI to the gNB (step 1420) indicating the measurement result (i.e., the carrier is available). The gNB receives the PUCCH IMI and may optionally perform a third CCA to ensure that the carrier is available from the gNB's perspective. When the third CCA passes (step 1422), the gNB can transmit data to the UE again (step 1424). The UE successfully receives the data transmission (step 1426) and sends a HARQ ACK message to the gNB, acknowledging that the data transmission has been received (step 1428). If the UE still fails to receive the data transmission in step 1426, the UE can continue to perform another CCA on the carrier in the next cycle configured by the gNB. The UE can periodically perform CCA until the UE successfully receives data transmission from the gNB.

[0245] In some embodiments, the initiating gNB initiates a COT to transmit data to multiple responder UEs. The initiating gNB can trigger an IMI report from a group of UEs, where each UE is configured by a higher layer with a group DCI, where the group DCI is associated with an RNTI for CRC scrambling used in the group DCI and has fields for the UEs in the group DCI. As described above, a group DCI can be sent to a group of UEs, requesting the UEs to perform interference measurements. The group DCI can indicate the resources each UE wants to monitor and measure, QCL information (as indicated in the TCI state), and the PUCCH resources to which the report is to be sent. This situation occurs in… Figure 15 As shown in the image.

[0246] Figure 15A schematic diagram of another embodiment of method 1500 for receiver-assisted channel access in unlicensed spectrum is shown. In this embodiment, the gNB performs CCA on a carrier (channel) used for communication with a group of UEs (i.e., UE1 to UE3 in this example). When the CCA passes (step 1502), the gNB sends a group DCI X_Y to the group of UEs (step 1504), requesting each UE to perform an interference measurement on the carrier (channel). For each of UE1-UE3, the group DCI X_Y can be configured with: the resources to be measured, the energy detection threshold to be used, and other information such as reported resources, QCL information, etc. When triggered by the group DCI X_Y, each of UE1-UE3 performs CCA to measure the configured channel. UE1 performs CCA, and the CCA passes (step 1506). UE1 sends IMI 1 (PUCCH 1 IMI 1) to the gNB on PUCCH 1, reporting its measurement result (step 1508). IMI 1 indicates that the channel is available to UE1. UE2 performs a CCA, but the CCA fails (step 1510). UE2 reports IMI 2 to the gNB on PUCCH 2 (PUCCH 2 IMI 2) (step 1512), indicating that the channel is unavailable for UE2. UE3 performs a CCA, and the CCA passes (step 1514). UE3 reports IMI 3 to the gNB on PUCCH 3 (PUCCH 3 IMI 3), indicating that the channel is available for UE3. When receiving reports from a group of UEs, the gNB may optionally perform another CCA, and when this CCA passes (step 1518), the gNB can determine whether to transmit to the group of UEs based on their respective reports. The gNB can determine whether to transmit to UE1 and UE3 based on the received PUCCH 1 IMI 1 and PUCCH 3 IMI 3 (indicating that the channel is available for UE1 and UE3), and transmit data to the corresponding UE1 and UE3 (steps 1520, 1522). The gNB can determine not to transmit to UE2 based on PUCCH 2 IMI 2 (indicating that the channel is unavailable for UE2). Since UE2's CCA fails, UE2 may not expect to receive any transmissions from the gNB (step 1526). UE1 and UE3 can receive their respective data transmissions (steps 1524, 1528) and send HARQ messages to the gNB (steps 1530, 1532) to indicate whether they have successfully received their respective data transmissions.

[0247] Figure 16A schematic diagram of another embodiment of method 1600 for receiver-assisted channel access in unlicensed spectrum is shown, highlighting the behavior of the gNB and UE. The gNB can perform LBT Category 4 (Extended CCA) in the channel of the unlicensed spectrum before initiating COT. The gNB can execute the extended CCA for COT initialization (step 1602). The gNB can determine whether the extended CCA is successful or passes (step 1604). When the extended CCA fails, the gNB can wait for the next COT opportunity (step 1606) and then proceed to step 1602 to execute the extended CCA before the next COT opportunity. When the extended CCA is successful, the gNB can broadcast system information in the channel (step 1608). The gNB can periodically send synchronization signals and system-related parameters. The UE can synchronize with the gNB and obtain system information (step 1610). The gNB can send a request to the UE or a group of UEs including the UE, requesting the UE or a group of UEs to perform interference measurements on the channel (step 1612). For example, this request could be an L1-IM request sent via a DCI with a CRC scrambled using a specific RNTI. The DCI may include the following indications: one or more (measurement) resources to be measured (e.g., one or more CSI-RS resource sets), TCI, the resource for interference measurement, and whether the reporting is aperiodic, periodic, or semi-static, the energy threshold for each resource set (unless configured by a higher layer), the reporting resource, QCL information, and the measurement duration to be performed. One or more of these resources may belong to the same carrier or different carriers. The UE may receive the DCI including the L1-IM request (step 1614).

[0248] The UE can decode the DCI and continue measuring interference on the indicated resource during the measurement duration (step 1616). The UE can then send a PUCCH IMI report to the gNB, indicating the interference status of the indicated resource (step 1618). The PUCCH IMI report may include an IMI map for the resource measured by the UE, and the IMI map may indicate the interference status of the corresponding measured resource, for example, whether the resource is available to the UE. The gNB can use the received PUCCH IMI report to schedule the next PDSCH transmission. The UE does not expect to receive transmissions on resources marked as unavailable (e.g., 0 in the IMI map). The gNB can receive the PUCCH IMI report and, based on the report, select one or more non-interfering resources from the resources measured by the UE (step 1620), i.e., resources indicated as available in the IMI report. If necessary, the gNB can perform a short LBT (step 1622) to check whether the channel is still available for transmission by the gNB. Then, the gNB can send a DCI to the UE, where the DCI may include PDSCH scheduling and HARQ PUCCH grant (step 1624). PDSCH scheduling includes scheduling information for downlink transmissions (e.g., PDSCH). PDSCH scheduling can be determined based on the PUCCH IMI report, and PDSCH can be scheduled on one or more selected non-interference resources. The UE receives the DCI with PDSCH scheduling and HARQ PUCCH grant (step 1626). The gNB can transmit data via PDSCH on non-interference resources reported in the PUCCH IMI report and selected by the gNB. The gNB transmits PDSCH via non-interference resources (step 1628), and the UE receives PDSCH via non-interference resources (step 1630). If necessary, the UE can perform a short LBT (step 1632) to determine if the channel in the uplink is idle. When the channel is idle, the UE sends a HARQ ACK / NACK message to the gNB (step 1634) indicating whether the UE has successfully received the PDSCH. The gNB receives the HARQ ACK / NACK message (step 1636). It should be noted that, depending on the interval between reception and transmission or between consecutive transmissions, the gNB and UE may or may not need to perform a short LBT during COT.

[0249] Figure 17A schematic diagram of another embodiment of method 1700 for receiver-assisted channel access in unlicensed spectrum is shown. Method 1700 may instruct operations to be performed at a base station (e.g., gNB), which may operate in shared spectrum or unlicensed spectrum. As shown, the gNB may determine whether a communication channel in the shared spectrum is idle (box 1702). This determination may be made by the gNB when there is data to be transmitted from the gNB in ​​the shared spectrum to the user equipment (UE). When the communication channel is determined to be idle, the gNB may send downlink control information (DCI) to trigger the UE to measure resources to determine whether the communication channel is available to the UE (box 1704). The gNB may receive a resource measurement report from the UE (box 1706). Based on the measurement report, the gNB may determine whether to transmit data to the UE in the communication channel (box 1708).

[0250] Figure 18 A schematic diagram of another embodiment of method 1800 for receiver-assisted channel access in unlicensed spectrum is shown. Method 1800 can instruct operations performed at the UE, which can operate in shared or unlicensed spectrum. As shown, the UE can receive downlink control information (DCI) from the gNB, triggering the UE to measure resources to determine whether a communication channel is available to the UE (box 1802). The UE can perform a measurement on the energy received on the resources when triggered by the DCI (box 1804) and generate a measurement report based on the measurement (box 1806). The UE can transmit the measurement report to the gNB (box 1808).

[0251] The various embodiments of the present invention can be implemented as computer-based methods. These embodiments can be performed by a processing system. Figure 19 A block diagram of an exemplary processing system 1900 for performing the methods described herein is shown, which may be installed in a host device. As shown, the processing system 1900 includes a processor 1904, a memory 1906, and interfaces 1910-1914, which may (or may not) be configured as follows: Figure 19As shown. Processor 1904 can be any component or set of components for performing computational and / or other processing-related tasks, and memory 1906 can be any component or set of components for storing programs and / or instructions executed by processor 1904. In one embodiment, memory 1906 includes a non-transitory computer-readable medium. Interfaces 1910, 1912, and 1914 can be any component or set of components that allow processing system 1900 to communicate with other devices / components and / or users. For example, one or more of interfaces 1910, 1912, and 1914 can be used to communicate data, control, or management messages from processor 1904 to applications installed on host devices and / or remote devices. As another example, one or more of interfaces 1910, 1912, and 1914 can be used to allow a user or user device (e.g., a personal computer (PC)) to interact / communicate with processing system 1900. Processing system 1900 may include Figure 19 Additional components not shown, such as long-term memory (e.g., non-volatile memory, etc.).

[0252] In some embodiments, the processing system 1900 is included in a network device that accesses or otherwise becomes part of a telecommunications network. In one example, the processing system 1900 is located in a network-side device within a wireless or wired telecommunications network, such as a base station, relay station, scheduler, controller, gateway, router, application server, or any other device within the telecommunications network. In other embodiments, the processing system 1900 is located in a user-side device accessing a wireless or wired telecommunications network, such as a mobile station, user equipment (UE), personal computer (PC), tablet computer, wearable communication device (e.g., smartwatch), or any other device used for accessing the telecommunications network.

[0253] In some embodiments, one or more of interfaces 1910, 1912, and 1914 connect the processing system 1900 to a transceiver for sending and receiving signaling over a telecommunications network. Figure 20This is a block diagram of a transceiver 2000 for transmitting and receiving signaling via a telecommunications network. The transceiver 2000 can be installed in a host device. As shown, the transceiver 2000 includes a network-side interface 2002, a coupler 2004, a transmitter 2006, a receiver 2008, a signal processor 2010, and a device-side interface 2012. The network-side interface 2002 may include any component or set of components for transmitting or receiving signaling via a wireless or wired telecommunications network. The coupler 2004 may include any component or set of components for facilitating bidirectional communication via the network-side interface 2002. The transmitter 2006 may include any component or set of components (e.g., an up-converter, a power amplifier, etc.) for converting a baseband signal into a modulated carrier signal suitable for transmission via the network-side interface 2002. The receiver 2008 may include any component or set of components (e.g., a down-converter, a low-noise amplifier, etc.) for converting a carrier signal received via the network-side interface 2002 into a baseband signal. The signal processor 2010 may include any component or set of components for converting baseband signals into data signals suitable for communication via one or more device-side interfaces 2012, or vice versa. The one or more device-side interfaces 2012 may include any component or set of components for data signal communication between the signal processor 2010 and components within a host device (e.g., processing system 1900, local area network (LAN) port, etc.).

[0254] Transceiver 2000 can send and receive signaling via any type of communication medium. In some embodiments, transceiver 2000 sends and receives signaling via a wireless medium. For example, transceiver 2000 can be a wireless transceiver for communicating according to a wireless telecommunications protocol, such as a cellular protocol (e.g., Long-Term Evolution (LTE), etc.), a wireless local area network (WLAN) protocol (e.g., Wi-Fi), or any other type of wireless protocol (e.g., Bluetooth, Near Field Communication (NFC), etc.). In these embodiments, network-side interface 2002 includes one or more antenna / radiating elements. For example, network-side interface 2002 may include a single antenna, multiple independent antennas, or a multi-antenna array for multi-layer communication, such as single-input multiple-output (SIMO), multiple-input single-output (MISO), multiple-input multiple-output (MIMO), etc. In other embodiments, transceiver 2000 transmits and receives signaling via wired media such as twisted-pair cable, coaxial cable, or optical fiber. A particular processing system and / or transceiver may utilize all of the components shown, or only a subset of these components, and the level of integration may vary from device to device.

[0255] The following references are related to the subject matter of this invention. The entire contents of each reference are incorporated herein by reference.

[0256] 3GPP TS 38.213, V16.5.0 (2021-03), "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical Layer Control Procedures (Version 16)";

[0257] 3GPP TS 38.214, V16.5.0 (2021-03), "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical Layer Data Procedures (Version 16)";

[0258] 3GPP TS 38.215, V16.4.0 (2020-12), "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical Layer Measurement (Version 16)";

[0259] 3GPP TS 37.213, V16.3.0 (2020-09), "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Procedures for Shared Spectrum Channel Access Physical Layer (Version 16)";

[0260] 3GPP TS 38.331, V16.4.1 (2021-03), "3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Radio Resource Control (RRC) Protocol Specification (Version 16)".

[0261] It should be understood that one or more steps of the methods provided in the embodiments herein can be performed by corresponding units or modules. For example, a signal can be transmitted by a transmitting unit or transmitting module. A signal can be received by a receiving unit or receiving module. A signal can be processed by a processing unit or processing module. Other steps can be performed by a channel listening unit / module, a determining unit / module, a retransmission unit / module, a configuration unit / module, an interference measurement unit / module, a reporting unit / module, a request unit / module, a triggering unit / module, and / or an energy detection unit / module. Each unit or module can be hardware, software, or a combination thereof. For example, one or more units / modules can be integrated circuits, such as field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).

[0262] Despite the detailed description, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention as defined by the appended claims. Furthermore, the scope of the invention is not intended to be limited to the specific embodiments described herein, and those skilled in the art will readily understand from the invention that processes, machines, articles of manufacture, material components, modules, methods, or steps (including those currently existing or to be developed hereafter) can perform substantially the same functions or achieve substantially the same effects as the corresponding embodiments described herein. Accordingly, the appended claims encompass such processes, machines, articles of manufacture, material components, modules, methods, or steps.

Claims

1. A method for receiver-assisted transmission in a shared spectrum, characterized in that, The method includes: When the gNB needs to send data to the first user equipment (UE), the gNB determines whether the communication channel in the shared spectrum is idle and available; When the communication channel is determined to be idle, the gNB sends a first downlink control information (DCI) to trigger the first UE to measure resources in order to determine whether the communication channel is available to the first UE. After sending the first DCI, the gNB receives a first measurement report from the first UE regarding the measurement of the resource; Based on the first measurement report, the gNB determines whether to transmit the data to the first UE in the communication channel; When the communication channel is determined to be available to the first UE based on the first measurement report, the gNB transmits the data to the first UE in the communication channel; The gNB receives a negative acknowledge (NACK) message from the first UE indicating that the first UE has not successfully received the data; After receiving the NACK message, the gNB receives a second measurement report from the first UE regarding the measurement of the resource; When the communication channel is determined to be available to the first UE based on the second measurement report, the gNB retransmits the data to the first UE in the communication channel.

2. The method according to claim 1, characterized in that, The method further includes: After receiving the first measurement report and before transmitting the data, the gNB re-determines the availability of the communication channel.

3. The method according to claim 1, characterized in that, The data is transmitted within the resource or a subset thereof.

4. The method according to claim 1, characterized in that, The method further includes: When the first measurement report determines that the communication channel is unavailable to the first UE, the gNB sends a second DCI to trigger the first UE to remeasure the resource to determine whether the communication channel is available to the first UE.

5. The method according to claim 1, characterized in that, The communication channel cannot be used by the first UE, and the method further includes: After receiving the first measurement report, within a preset time period, the gNB receives a second measurement report from the first UE; and When the communication channel is determined to be available to the first UE based on the second measurement report, the gNB transmits the data to the first UE.

6. The method according to any one of claims 1 to 5, characterized in that, The gNB determines whether the communication channel is idle by including: The gNB performs a clear channel assessment (CCA) on the communication channel.

7. The method according to any one of claims 1 to 5, characterized in that, The resources include one or more carriers, or one or more resource sets.

8. The method according to any one of claims 1 to 5, characterized in that, The resources include channel state information-interference measurement (CSI-IM) resources or CSI-IM resource sets.

9. The method according to any one of claims 1 to 5, characterized in that, The resources include channel state information-reference signal (CSI-RS) resources or CSI-RS resource sets.

10. The method according to any one of claims 1 to 5, characterized in that, The resources include carrier bandwidth or a subset thereof.

11. The method according to any one of claims 1 to 5, characterized in that, The resources include time resources, frequency resources, space resources, or a combination of time resources, frequency resources, and space resources.

12. The method according to any one of claims 1 to 5, characterized in that, The first measurement report indicates: Whether the energy detected on the resource or a subset of the resource exceeds a threshold; Is the resource or the subset thereof free? or The energy detected on the resource or a subset of the resource.

13. The method according to any one of claims 1 to 5, characterized in that, The first measurement report includes an interference measurement indicator (IMI) indicating the measurement results of the resource or a subset of the resource.

14. The method according to any one of claims 1 to 5, characterized in that, The method further includes: the gNB transmitting first information about the resource.

15. The method according to any one of claims 1 to 5, characterized in that, The method further includes: the gNB transmitting second information, the second information including any one or more of the following: Resources used for reporting resource measurements; Quasi-co-location (QCL) information for measurement resources; The transmission configuration indication (TCI) status indicates the QCL type of the measurement resource; The measurement time period for the resource measurement; or Measure the threshold.

16. The method according to claim 14, characterized in that, The first information or the second information is transmitted in the first DCI or via higher-layer signaling.

17. The method according to any one of claims 1 to 5, characterized in that, Transmitting the first DCI includes: The gNB transmits the first DCI to a group of UEs including the first UE, triggering each UE in the group to measure the corresponding resources to determine whether the communication channel is available to the corresponding UE.

18. The method according to claim 17, characterized in that, The first DCI has a cyclic redundancy check (CRC) scrambled using a group radio network temporary identifier (RNTI) associated with the group of UEs, and for each UE, the first DCI includes one or more of the following: The corresponding resources of the corresponding UE; The QCL information of the corresponding measurement resource of the corresponding UE; Measurement time window; Measurement threshold; or Resources used for reporting measurements.

19. The method according to any one of claims 1 to 5, characterized in that, The first DCI also includes a field for requesting the first UE to report an L1-IM report or a CSI-RS report regarding the measurement of the resource.

20. The method according to any one of claims 1 to 5, characterized in that, The first DCI also includes any one or more of the following: Channel State Information-Interference Measurement (CSI-IM) time-domain indicator, indicating the CSI-IM configuration used for interference measurement; Period and offset parameters, indicating the period and timing offset used for the interference measurement and reporting; or The IMI bit length parameter indicates the number of bits used to encode the measurement results of the interference measurement.

21. The method according to any one of claims 1 to 5, characterized in that, The first DCI also includes one or more of the following: Channel state information-interference measurement (CSI-IM) time-domain indicator, indicating the CSI-IM configuration for measurements related to interference statistics; Period and offset parameters, indicating the period and timing offset used for the measurement and reporting of the interference statistics; or The statistics type parameter indicates the type of interference statistics that the UE should report for each resource. The types of interference statistics include the following within the measurement duration period: average channel idle duration, standard deviation of channel idle duration, average channel busy duration, longest channel idle duration, shortest channel idle duration, longest channel busy duration, or shortest channel busy duration.

22. A method for receiver-assisted transmission in a shared spectrum, characterized in that, The method includes: The user equipment (UE) receives the first downlink control information (DCI) from the gNB, triggering the UE to measure resources to determine whether a communication channel in the shared spectrum is available to the UE; After being triggered by the DCI, the UE performs a first measurement on the energy received on the resource; The UE generates a first measurement report based on the first measurement; The UE transmits the first measurement report to the gNB; When the communication channel is available to the UE, the UE receives data from the gNB in ​​the communication channel of the shared spectrum after transmitting the first measurement report; The UE transmits a negative acknowledgment (NACK) message to the gNB indicating that the UE has not successfully received the data; The UE performs a second measurement on the energy received on the resource to determine whether the communication channel is available; The UE transmits a second measurement report to the gNB, the second measurement report being based on the second measurement; After transmitting the second measurement report, the UE receives the data retransmitted by the gNB in ​​the communication channel of the shared spectrum.

23. The method according to claim 22, characterized in that, The data is received in the resource or in a subset of the resource.

24. The method according to claim 22, characterized in that, The method further includes: When the communication channel is unavailable to the UE, the UE receives a second DCI from the gNB, triggering the UE to remeasure the resource to determine whether the communication channel is available.

25. The method according to claim 22, characterized in that, The communication channel is not available to the UE, and the method further includes: The UE performs a second measurement on the resource to generate a second measurement report; The UE transmits the second measurement report to the gNB; After transmitting the second measurement report, the UE receives data from the gNB in ​​the communication channel.

26. The method according to any one of claims 22 to 25, characterized in that, The resources include one or more carriers, or one or more resource sets.

27. The method according to any one of claims 22 to 25, characterized in that, The resources include channel state information-interference measurement (CSI-IM) resources or CSI-IM resource sets.

28. The method according to any one of claims 22 to 25, characterized in that, The resources include channel state information-reference signal (CSI-RS) resources or CSI-RS resource sets.

29. The method according to any one of claims 22 to 25, characterized in that, The resources include carrier bandwidth or a subset thereof.

30. The method according to any one of claims 22 to 25, characterized in that, The resources include time resources, frequency resources, space resources, or a combination of time resources, frequency resources, and space resources.

31. The method according to any one of claims 22 to 25, characterized in that, The first measurement report indicates: Whether the energy detected on the resource or a subset of the resource exceeds a threshold; Is the resource or the subset thereof free? or The energy detected on the resource or a subset of the resource.

32. The method according to any one of claims 22 to 25, characterized in that, The first measurement report includes an interference measurement indicator (IMI) indicating the measurement results of the resource or a subset of the resource.

33. The method according to any one of claims 22 to 25, characterized in that, Performing the first measurement includes: The UE generates a component carrier received signal strength indicator (CC-RSSI) based on the energy received on the resource during the measurement period.

34. The method according to any one of claims 22 to 25, characterized in that, The method further includes: The UE receives the first information about the resource from the gNB.

35. The method according to any one of claims 22 to 25, characterized in that, The method further includes: The UE receives second information from the gNB, the second information including any one or more of the following: Resources used for reporting resource measurements; Quasi-co-location (QCL) information for measurement resources; The transmission configuration indication (TCI) status indicates the QCL type of the measurement resource; The measurement time period for the resource measurement; or Measure the threshold.

36. The method according to claim 34, characterized in that, The first information or the information is received in the first DCI or via higher-layer signaling.

37. The method according to any one of claims 22 to 25, characterized in that, The first DCI triggers each UE in a group of UEs to measure the corresponding resources to determine whether the communication channel is available to the corresponding UE.

38. The method according to claim 37, characterized in that, The first DCI has a cyclic redundancy check (CRC) scrambled using the group radio network temporary identifier (RNTI) associated with the group of UEs.

39. The method according to any one of claims 22 to 25, characterized in that, The first DCI also includes a field for requesting the UE to report an L1-IM report or a CSI-RS report.

40. The method according to any one of claims 22 to 25, characterized in that, The first DCI also includes any one or more of the following: Channel State Information-Interference Measurement (CSI-IM) time-domain indicator, indicating the CSI-IM configuration used for interference measurement; Period and offset parameters, indicating the period and offset used for the interference measurement and reporting; or The IMI bit length parameter indicates the number of bits used to encode the measurement results of the interference measurement.

41. The method according to any one of claims 22 to 25, characterized in that, The first measurement report includes an interference statistics measurement indicator (STA-IMI) that indicates the measurement results statistics for the resource or a subset of the resource. The statistics include the following within the measurement duration period: average channel idle duration, standard deviation of channel idle duration, average channel busy duration, longest channel idle duration, shortest channel idle duration, longest channel busy duration, or shortest channel busy duration.

42. An apparatus for receiver-assisted transmission in a shared spectrum, characterized in that, The device includes: Non-transient memory, including instructions; One or more processors communicate with the memory storage, wherein the instructions, when executed by the one or more processors, cause the device to perform the following operations: When the device needs to send data to the first user equipment (UE), it determines whether the communication channel in the shared spectrum is idle and available; When it is determined that the communication channel is available, a first downlink control information (DCI) is sent to trigger the first UE to measure resources in order to determine whether the communication channel is available to the first UE. After sending the first DCI, a first measurement report about the measurement of the resource is received from the first UE; Based on the first measurement report, determine whether to transmit the data to the first UE in the communication channel.

43. An apparatus for receiver-assisted transmission in a shared spectrum, characterized in that, The device includes: Non-transient memory, including instructions; One or more processors communicate with the memory storage, wherein the instructions, when executed by the one or more processors, cause the device to perform the following operations: The device receives first downlink control information (DCI) from the gNB, triggering the device to measure resources to determine whether a communication channel in the shared spectrum is available to the device. Upon being triggered by the DCI, a first measurement is performed on the energy received on the resource; A first measurement report is generated based on the first measurement; Transmit the first measurement report.

44. A non-transitory computer-readable medium for storing computer instructions, characterized in that, The computer instructions, when executed by one or more processors of the device, cause the device to perform the following operations: When the device needs to send data to the first user equipment (UE), it determines whether the communication channel in the shared spectrum is idle and available; When it is determined that the communication channel is available, a first downlink control information (DCI) is sent to trigger the first UE to measure resources in order to determine whether the communication channel is available to the first UE. After sending the first DCI, a first measurement report about the measurement of the resource is received from the first UE; as well as Based on the first measurement report, determine whether to transmit the data to the first UE in the communication channel.

45. A non-transitory computer-readable medium storing computer instructions, characterized in that, The computer instructions, when executed by one or more processors of the device, cause the device to perform the following operations: The device receives first downlink control information (DCI) from the gNB, triggering the device to measure resources to determine whether a communication channel in the shared spectrum is available to the device. Upon being triggered by the DCI, a first measurement is performed on the energy received on the resource; A first measurement report is generated based on the first measurement; Transmit the first measurement report.

46. ​​A system for receiver-assisted transmission in a shared spectrum, characterized in that, The system includes: User equipment (UE); and gNB communicating with the UE; and The gNB is used to perform the following operations: When the gNB needs to send data to the UE, it determines whether the communication channel in the shared spectrum is idle and available; When it is determined that the communication channel is available, downlink control information (DCI) is sent to trigger the UE measurement resources to determine whether the communication channel is available to the UE. After sending the DCI, a measurement report of the resource is received from the UE; Based on the measurement report, determine whether to transmit the data to the UE in the communication channel; The UE is used to perform the following operations: and Receive the DCI from the gNB; Upon being triggered by the DCI, a first measurement is performed on the energy received on the resource; Based on the first measurement, generate the measurement report; and Transmit the measurement report.

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