Methods and apparatuses for using quasi co-location (QCL) in mTRP-enabled networks

Abstract

The specification describes a terminal device comprising: means for receiving quasi co-location, QCL, information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; means for receiving at least one parameter whose value depends on whether the source reference signal is transmitted by a single transmission reception point, TRP, or multiple TRPs in a serving cell of the terminal device; means for receiving the source reference signal; means for determining, based on the value of the at least one parameter, a subset of the one or more channel characteristics identified by the QCL information for receiving a target reference signal indicated as being quasi co-located with the source reference signal; means for estimating a value of the subset of channel characteristics based on the received source reference signal; and means for receiving the target reference signal using the estimated value of the subset of channel characteristics.

Description

Technical Field

[0001] This specification relates to the determination of quasi-co-located (QCL) sources in multi-transmitter and receiver point (mTRP) scenarios. Background Technology

[0002] In short, mTRP enables network base stations (such as gNBs) to use more than one TRP to communicate with a given user equipment (UE) or terminal device. Since release 2 (i.e., since release 16), 5G New Radio (NR) has been enhanced with mTRP functionality. Furthermore, 6G is expected to have mTRP as a supported scenario from the first release of 6G. This is because mTRP scenarios are needed to provide capacity and coverage improvements compared to 5G NR. Summary of the Invention

[0003] In a first aspect, this specification describes a terminal device comprising: components for receiving quasi-co-located QCL information, the quasi-co-located QCL information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; components for receiving at least one parameter, the value of the at least one parameter depending on whether the source reference signal is transmitted by a single Transmit Receive Point (TRP) or multiple TRPs in the serving cell of the terminal device; components for receiving the source reference signal; components for determining a subset of the one or more channel characteristics identified by the QCL information based on the value of the at least one parameter, for receiving a target reference signal indicated as quasi-co-located with the source reference signal; components for estimating the value of the subset of channel characteristics based on the received source reference signal; and components for receiving the target reference signal using the estimated value of the subset of channel characteristics.

[0004] In some examples, one or more channel characteristics identified by QCL information include average delay and Doppler shift, and in such examples, if i) the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay and exclude Doppler shift. Conversely, if i) the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay and Doppler shift.

[0005] In some examples, one or more channel characteristics identified by QCL information include average delay, Doppler shift, and spatial receiver parameters. In such examples, if i) the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay instead of Doppler shift and spatial receiver parameters. Conversely, if i) the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay, Doppler shift, and spatial receiver parameters.

[0006] At least one of the QCL information, configuration information for the source reference signal, or configuration information for the target reference signal may include at least one parameter.

[0007] In some examples, the at least one parameter includes a parameter, and the configuration information of the target reference signal includes the parameter, and the value of the parameter indicates to the terminal device whether the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, wherein the transmission mode of the source reference signal is one of the following: the source reference signal is transmitted by a single TRP in the serving cell, or the source reference signal is transmitted by multiple TRPs in the serving cell. In such examples, the at least one parameter may include a second parameter, the value of which indicates whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell. At least one of the QCL information, the configuration information for the source reference signal, or the configuration information for the target reference signal may include the second parameter.

[0008] In other examples, at least one parameter may include a parameter whose value indicates a subset of one or more channel characteristics identified in the QCL information that can be used to receive a target reference signal. Configuration information for the source reference signal or configuration information for the target reference signal includes this parameter. For example, the QCL information may indicate a QCL type corresponding to multiple channel characteristics associated with the source reference signal, and the value of this parameter may indicate a QCL subtype corresponding to a subset of the multiple channel characteristics corresponding to the QCL type, and the subset of channel characteristics determined based on the value of the parameter is a subset of the multiple channel characteristics corresponding to the QCL type. Alternatively, the QCL information may indicate a QCL type corresponding to multiple channel characteristics associated with the source reference signal, and the value of this parameter represents a bitmap or mask. The terminal device may include components for applying a bitmap or mask to multiple channel characteristics to determine a subset of the multiple channel characteristics corresponding to the QCL type, and the subset of channel characteristics determined based on the value of this parameter is a subset of the multiple channel characteristics corresponding to the QCL type.

[0009] In other examples, at least one parameter includes a value that indicates to the terminal device whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell.

[0010] In the examples described herein, the source reference signal may be a reference signal broadcast for initial access, and the target reference signal may be a reference signal used to track the channel in the time and frequency domains when the terminal is actively communicating within the serving cell. For example, the source reference signal may be a synchronization signal block (SSB), and the target reference signal may be a channel state information reference signal (CSI-RS), such as a tracking reference signal.

[0011] QCL information may include the Transport Configuration Indicator (TCI) status, and the target reference signal can be indicated as quasi-co-located with the source reference signal by identifying the TCI status.

[0012] In a second aspect, this specification describes a network node comprising: components for operating a cell of a serving terminal equipment; components for transmitting quasi-co-located QCL information to the terminal equipment, the quasi-co-located QCL information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; components for transmitting the source reference signal; components for transmitting at least one parameter to the terminal equipment, the value of the at least one parameter being set according to whether the source reference signal is transmitted by a single Transmit Receive Point (TRP) or multiple TRPs in the serving cell; and components for transmitting a target reference signal indicated as quasi-co-located with the source reference signal.

[0013] The value of at least one parameter can be used by the terminal device to determine a subset of one or more channel characteristics identified in the QCL information, which can be used by the terminal device to receive a target reference signal.

[0014] At least one of the QCL information, configuration information for the source reference signal, or configuration information for the target reference signal may include at least one parameter.

[0015] In some examples, at least one parameter includes a parameter whose value indicates to the terminal device whether the source reference signal is transmitted by a single TRP in the serving cell or by multiple TRPs.

[0016] In other examples, at least one parameter includes a value that indicates to the terminal device whether the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, wherein the transmission mode of the source reference signal is one of the following: the source reference signal is transmitted by a single TRP in the serving cell, or the source reference signal is transmitted by multiple TRPs in the serving cell. In such examples, configuration information for the target reference signal may include this parameter.

[0017] In other examples, at least one parameter includes a parameter, and the QCL information indicates the QCL type corresponding to multiple channel characteristics associated with the source reference signal. Configuration information for the source reference signal or configuration information for the target reference signal includes this parameter, and the value of this parameter indicates the QCL subtype corresponding to a subset of the multiple channel characteristics corresponding to the QCL type.

[0018] In a third aspect, this specification describes a method comprising: receiving quasi-co-located QCL information, the QCL information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; receiving at least one parameter, the value of the at least one parameter depending on whether the source reference signal is transmitted by a single Transmit Receive Point (TRP) or multiple TRPs in the serving cell of the terminal device; receiving the source reference signal; and a component for determining, based on the value of the at least one parameter, a subset of the one or more channel characteristics identified by the QCL information for receiving a target reference signal indicated as quasi-co-located with the source reference signal; estimating the value of the subset of channel characteristics based on the received source reference signal; and receiving the target reference signal using the estimated value of the subset of channel characteristics.

[0019] In some examples, one or more channel characteristics identified by QCL information include average delay and Doppler shift, and in such examples, if i) the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay and exclude Doppler shift. Conversely, if i) the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay and Doppler shift.

[0020] In some examples, one or more channel characteristics identified by QCL information include average delay, Doppler shift, and spatial receiver parameters. In such examples, if i) the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay but excludes Doppler shift and spatial receiver parameters. Conversely, if i) the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay, Doppler shift, and spatial receiver parameters.

[0021] At least one of the QCL information, configuration information for the source reference signal, or configuration information for the target reference signal may include at least one parameter.

[0022] In some examples, the at least one parameter includes a parameter, and the configuration information of the target reference signal includes the parameter, and the value of the parameter indicates to the terminal device whether the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, wherein the transmission mode of the source reference signal is one of the following: the source reference signal is transmitted by a single TRP in the serving cell, or the source reference signal is transmitted by multiple TRPs in the serving cell. In such examples, the at least one parameter may include a second parameter, the value of which indicates whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell. At least one of the QCL information, the configuration information for the source reference signal, or the configuration information for the target reference signal may include the second parameter.

[0023] In other examples, at least one parameter may include a parameter whose value indicates a subset of one or more channel characteristics identified in the QCL information that can be used to receive a target reference signal. Configuration information for the source reference signal or configuration information for the target reference signal includes this parameter. For example, the QCL information may indicate a QCL type corresponding to multiple channel characteristics associated with the source reference signal, the parameter value may indicate a QCL subtype corresponding to a subset of the multiple channel characteristics corresponding to the QCL type, and the subset of channel characteristics determined based on the parameter value is a subset of the multiple channel characteristics corresponding to the QCL type. Alternatively, the QCL information may indicate a QCL type corresponding to multiple channel characteristics associated with the source reference signal, the parameter value representing a bitmap or mask, and the method may include applying a bitmap or mask to multiple channel characteristics to determine a subset of the multiple channel characteristics corresponding to the QCL type, and the subset of channel characteristics determined based on the parameter value is a subset of the multiple channel characteristics corresponding to the QCL type.

[0024] In other examples, at least one parameter includes a parameter whose value indicates to the terminal device whether the source reference signal was transmitted by a single TRP or multiple TRPs in the serving cell.

[0025] In some examples described herein, the source reference signal may be a reference signal broadcast for initial access, and the target reference signal may be a reference signal used to track the channel in the time and frequency domains when the terminal is actively communicating within the serving cell. For example, the source reference signal may be a synchronization signal block (SSB), and the target reference signal may be a channel state information reference signal (CSI-RS), such as a tracking reference signal.

[0026] QCL information may include the Transport Configuration Indicator (TCI) status, and the target reference signal can be indicated as quasi-co-located with the source reference signal by identifying the TCI status.

[0027] In a fourth aspect, this specification describes a method that can be performed by a network node, the method comprising: operating a cell of a serving terminal device; transmitting to the terminal device quasi-co-address QCL information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; transmitting the source reference signal; transmitting to the terminal device at least one parameter, the value of the at least one parameter being set according to whether the source reference signal is transmitted by a single Transmit Receive Point (TRP) or by multiple TRPs in the serving cell; and transmitting a target reference signal indicated to be quasi-co-addressable with the source reference signal.

[0028] The value of at least one parameter can be used by the terminal device to determine a subset of one or more channel characteristics identified in the QCL information, which can be used by the terminal device to receive a target reference signal.

[0029] At least one of the QCL information, configuration information for the source reference signal, or configuration information for the target reference signal may include at least one parameter.

[0030] In some examples, at least one parameter includes a value that indicates to the terminal device whether the source reference signal is transmitted by a single TRP in the serving cell or by multiple TRPs.

[0031] In other examples, at least one parameter includes a value that indicates to the terminal device whether the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, wherein the transmission mode of the source reference signal is one of the following: the source reference signal is transmitted by a single TRP in the serving cell, or the source reference signal is transmitted by multiple TRPs in the serving cell. In such examples, configuration information for the target reference signal may include this parameter.

[0032] In other examples, at least one parameter includes a parameter, and the QCL information indicates the QCL type corresponding to multiple channel characteristics associated with the source reference signal. Configuration information for the source reference signal or configuration information for the target reference signal includes this parameter, and the value of this parameter indicates the QCL subtype corresponding to a subset of the multiple channel characteristics corresponding to the QCL type.

[0033] In a fifth aspect, this specification describes an apparatus (e.g., a terminal device or a component of a terminal device) comprising at least one processor and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus to at least: receive quasi-co-address QCL information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; receive at least one parameter whose value depends on whether the source reference signal is transmitted by a single Transmit Receive Point (TRP) or multiple TRPs in the serving cell of the terminal device; receive the source reference signal; and components for determining, based on the value of the at least one parameter, a subset of the one or more channel characteristics identified by the QCL information for receiving a target reference signal indicated as quasi-co-addressable with the source reference signal; estimating the value of the subset of channel characteristics based on the received source reference signal; and receiving the target reference signal using the estimated value of the subset of channel characteristics.

[0034] In some examples, one or more channel characteristics identified by QCL information include average delay and Doppler shift, and in such examples, if i) the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay and exclude Doppler shift. Conversely, if i) the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay and Doppler shift.

[0035] In some examples, one or more channel characteristics identified by QCL information include average delay, Doppler shift, and spatial receiver parameters. In such examples, if i) the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay but excludes Doppler shift and spatial receiver parameters. Conversely, if i) the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then a subset of the channel characteristics may include average delay, Doppler shift, and spatial receiver parameters.

[0036] At least one of the QCL information, configuration information for the source reference signal, or configuration information for the target reference signal may include at least one parameter.

[0037] In some examples, the at least one parameter includes a parameter, and the configuration information of the target reference signal includes the parameter, and the value of the parameter indicates to the terminal device whether the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, wherein the transmission mode of the source reference signal is one of the following: the source reference signal is transmitted by a single TRP in the serving cell, or the source reference signal is transmitted by multiple TRPs in the serving cell. In such examples, the at least one parameter may include a second parameter, the value of which indicates whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell. At least one of the QCL information, the configuration information for the source reference signal, or the configuration information for the target reference signal may include the second parameter.

[0038] In other examples, at least one parameter may include a parameter whose value indicates a subset of one or more channel characteristics identified in the QCL information that can be used to receive a target reference signal. Configuration information for the source reference signal or configuration information for the target reference signal includes this parameter. For example, the QCL information may indicate a QCL type corresponding to multiple channel characteristics associated with the source reference signal, the parameter value may indicate a QCL subtype corresponding to a subset of the multiple channel characteristics corresponding to the QCL type, and the subset of channel characteristics determined based on the parameter value is a subset of the multiple channel characteristics corresponding to the QCL type. Alternatively, the QCL information may indicate a QCL type corresponding to multiple channel characteristics associated with the source reference signal, the parameter value representing a bitmap or mask, which may cause the device to apply a bitmap or mask to multiple channel characteristics to determine a subset of the multiple channel characteristics corresponding to the QCL type, and the subset of channel characteristics determined based on the parameter value is a subset of the multiple channel characteristics corresponding to the QCL type.

[0039] In other examples, at least one parameter includes a parameter whose value indicates to the terminal device whether the source reference signal was transmitted by a single TRP or multiple TRPs in the serving cell.

[0040] In the examples described herein, the source reference signal may be a reference signal broadcast for initial access, and the target reference signal may be a reference signal used to track the channel in the time and frequency domains when the terminal is actively communicating within the serving cell. For example, the source reference signal may be a synchronization signal block (SSB), and the target reference signal may be a channel state information reference signal (CSI-RS), such as a tracking reference signal.

[0041] QCL information may include the Transport Configuration Indicator (TCI) status, and the target reference signal can be indicated as quasi-co-located with the source reference signal by identifying the TCI status.

[0042] In a sixth aspect, this specification describes an apparatus (e.g., a network node or a component of a network node) comprising at least one processor and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus to at least: operate a cell of a serving terminal device; transmit quasi-co-address QCL information to the terminal device, the quasi-co-address QCL information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; transmit the source reference signal; transmit at least one parameter to the terminal device, the value of the at least one parameter being set according to whether the source reference signal is transmitted by a single Transmit Receive Point (TRP) or by multiple TRPs in the serving cell; and transmit a target reference signal indicated to be quasi-co-addressable with the source reference signal.

[0043] The value of at least one parameter can be used by the terminal device to determine a subset of one or more channel characteristics identified in the QCL information, which can be used by the terminal device to receive a target reference signal.

[0044] At least one of the QCL information, configuration information for the source reference signal, or configuration information for the target reference signal may include at least one parameter.

[0045] In some examples, at least one parameter includes a parameter whose value indicates to the terminal device whether the source reference signal is transmitted by a single TRP in the serving cell or by multiple TRPs.

[0046] In other examples, at least one parameter includes a value that indicates to the terminal device whether the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, wherein the transmission mode of the source reference signal is one of the following: the source reference signal is transmitted by a single TRP in the serving cell, or the source reference signal is transmitted by multiple TRPs in the serving cell. In such examples, configuration information for the target reference signal may include this parameter.

[0047] In other examples, at least one parameter includes a parameter, and the QCL information indicates the QCL type corresponding to multiple channel characteristics associated with the source reference signal. Configuration information for the source reference signal or configuration information for the target reference signal includes this parameter, and the value of this parameter indicates the QCL subtype corresponding to a subset of the multiple channel characteristics corresponding to the QCL type.

[0048] In a seventh aspect, this specification describes a non-transitory computer-readable medium including program instructions stored thereon, the program instructions being used to cause any operation described with reference to any of the first to sixth aspects to be performed. Attached Figure Description

[0049] To better understand this application, reference will now be made to the accompanying drawings by way of example, in which: Figure 1 This is a schematic diagram illustrating the concept of a quasi-co-located QCL; Figure 2A and Figure 2B It is a schematic diagram of two different transmission modes that can be adopted by modern telecommunications networks and future telecommunications networks; Figure 3 This is a message flow diagram illustrating the various messages that can be transmitted and the operations that can be performed according to the various examples described herein; Figure 4 and Figure 5 These are flowcharts illustrating various operations that can be performed by terminal devices and network nodes, respectively, according to the various examples described herein; Figure 6 It can be configured as an execution reference. Figures 1 to 5 A schematic diagram illustrating example configurations of terminal devices for various operations described; Figure 7 It can be configured as an execution reference. Figures 1 to 5 A diagram illustrating example configurations of network nodes for various operations; and Figure 8 It is a diagram of a computer-readable medium on which computer-readable code can be stored. Detailed Implementation

[0050] The scope of protection sought by the various embodiments of this disclosure is set forth in the independent claims. Embodiments and features described in the specification that do not fall within the scope of the independent claims (if any) are to be interpreted as examples useful for understanding the various embodiments of this disclosure.

[0051] In the following description and accompanying drawings, the same reference numerals always refer to the same elements.

[0052] This specification relates to the determination of quasi-co-located (QCL) sources in mTRP scenarios within wireless communication networks. According to R1-1700771 (Ericsson: "On Spatial QCL Definition"), the QCL is defined as follows: "If the properties of a channel that transmits symbols on one antenna port can be inferred from the properties of a channel that transmits symbols on another antenna port, then the two antenna ports are called quasi-co-located."

[0053] In short, while antenna ports define the correlation between symbols within the same antenna port due to the specific channel model used, QCL defines the correlation between symbols from different antenna ports due to the similar channel conditions experienced.

[0054] Therefore, quasi-co-addressing is a natural way to describe the relationship between two different signals. When signal (A) is said to be “quasi-co-addressed” (QCLed) with another signal (B), it means that the two signals (A) and (B) experienced very similar channel conditions. As will be understood, in order for them to experience such similar channel conditions, they are most likely to originate from the same location and from the same antenna and / or antenna configuration (e.g., using the same precoding weights). More specifically, quasi-co-addressing between two signals (A) and (B) can imply that they were transmitted from the same Transmitter-Receiver Point (TRP) to which the same spatial filter (beam) was applied to both signals (A) and (B), and therefore, the receiver (e.g., User Equipment, UE) can use the same receive spatial filter to receive both signals (A) and (B). Furthermore, since the two signals arrive at the receiver through similar channels, if the receiver can detect one of the signals and determine the channel properties of the signal, it will greatly help the receiver detect and receive the other signal.

[0055] For example, when the Physical Downlink Control Channel (PDCCH) signal from the gNB is in QCL with the Tracking Reference Signal (TRS), it means that the PDCCH signal will experience similar channel conditions to the TRS. Therefore, when detecting the PDCCH signal, channel information estimated from the TRS can be used. For example, the UE can perform filter and channel parameter estimation based on the TRS, and apply the estimated filter parameters when performing PDCCH signal detection and demodulation.

[0056] The 3GPP (3rd Generation Mobile Telecommunications Partnership) standards development organization defines several characteristics (or attributes) to define the downlink channel conditions listed below: -Doppler frequency shift -Doppler extension -Average latency - Delay Spread -Spatial Rx parameter Doppler shift is the change in frequency of a radio signal caused by the relative motion of the receiver. For example, if a gNB transmits a radio signal at frequency "X", and the receiver (UE) is moving away from or closer to the gNB, the same radio signal will have a different frequency "Y" when it reaches the UE. Doppler spread (also known as fading rate) is the difference between the signal frequency at the transmitter and receiver relative to time. Average delay is the average time it takes for a signal transmitted from one or more antennas to reach the receiver. Delay spread is the difference between the arrival time of the earliest significant multipath component (typically a line-of-sight (LOS) component) and the arrival time of the last multipath component. Spatial receiver (Rx) parameters refer to beamforming properties of the downlink received signal, such as the dominant angle of arrival or average angle of arrival at the UE.

[0057] A predefined group of characteristics shared by two QCL signals can be indicated to the receiver via one or more QCL types. 3GPP TS 38.214 Release 16.2.0 defines four different types of QCLs, as follows: -'QCL-TypeA': {Doppler frequency shift, Doppler spread, average delay, delay spread} -'QCL-TypeB': {Doppler frequency shift, Doppler spread} -'QCL-TypeC': {Doppler shift, average delay} -'QCL-TypeD': {Space Rx parameter} Different QCL-Types may be associated with different applications. For example, QCL-Type A and QCL-Type B may be associated with determining Channel State Information (CSI), QCL-Type C may be associated with deriving time and / or frequency synchronization information for receiving a target reference signal and with determining channel measurements such as Reference Signal Received Power (RSRP), and QCL-Type D may be associated with supporting beamforming. One or more of the QCL-Types can be used to indicate the relationship between two related signals. For example, and by way of example only, two signals can be related via QCL-Type C and QCL-Type D.

[0058] Figure 1This diagram illustrates how QCL is utilized in the uplink and downlink directions. In both cases, a source signal and a target reference signal exist. The source signal is typically a downlink reference signal. The network transmits the source signal received by the terminal equipment (UE). Based on the received source signal, the UE estimates multiple channel characteristics. Then, when the UE receives the target reference signal, it can use or apply one or more of these estimated characteristics. Which estimated channel characteristic is used depends on the "QCL relationship" between the source and target reference signals. The network can indicate the QCL relationship between the two signals to the UE via QCL information. For example, the QCL information can indicate one or more of the QCL-Types discussed above. Therefore, the estimated channel characteristics applied by the UE when receiving the target reference signal depend on the QCL information indicated by the network. For example, if the QCL relationship is indicated as QCL-Type A, the UE can apply each of the estimated Doppler shift, Doppler spread, average delay, and delay spread when receiving the target reference signal. On the other hand, if the QCL relationship is indicated as QCL-Type C, the UE can apply each of the estimated Doppler shift and average delay when receiving the target reference signal. Other channel characteristics not indicated by QCL information may not be applied by the UE. Additionally, in some examples, other channel characteristics not indicated by QCL information may not be estimated by the UE.

[0059] like Figure 1 As shown, in the downlink direction, applicable channel characteristics include Doppler shift, Doppler spread, average delay, delay spread, and spatial Rx parameters. In the uplink direction, the UE can estimate the transmit beam used by the TRP of the source signal and the path loss.

[0060] Within an NR network, an example of a source signal is the Synchronization Signal Block (SSB). An example of a target reference signal is the Tracking Reference Signal (TRS), which can be used for constant time and frequency synchronization tracking, time and frequency offset estimation, and Doppler and time-domain channel parameter estimation. However, as mentioned above, the TRS is also a source signal. For example, a UE can use estimated parameters and channel filters from the TRS to receive the PDCCH, Physical Downlink Shared Channel (PDSCH), and other CSI-RS. In other words, the TRS is the QCL source signal used for PDCCH, PDSCH, and other CSI-RS. Therefore, the TRS is the primary NR signal used for time and frequency synchronization tracking and is a prerequisite for receiving downlink signals and channels.

[0061] The QCL source for TRS is the Synchronization Signal Block (SSB). Specifically, as can be seen from 3GPP TS 38.214, the SSB is the source of QCL-Type C and QCL-Type D for TRS:

[0062] QCL between TRS and SSB via Type C and Type D means that TRS and SSB experience similar radio channels that share similar properties in terms of average delay and Doppler shift, and the UE can assume that the same spatial reception filter is used to receive SSB as for receiving TRS.

[0063] Since release 2 (i.e., release 16), 5G NR has been enhanced with the mTRP feature. Furthermore, 6G is expected to have mTRP as a supported scenario from the first release of 6G, as the mTRP scenario requires capacity and coverage improvements compared to 5G NR. In short, mTRP enables network base stations (e.g., gNBs) to use more than one TRP to communicate with a given UE.

[0064] In the mTRP scenario of 5G NR, the source signal (such as SSB) can be transmitted as a single-frequency network (SFN) transmission from multiple TRPs. That is, multiple TRPs in a cell can simultaneously transmit the same source signal on the same time and frequency resources. Alternatively, the source signal can be transmitted on a per-TRP basis. That is, each TRP in the cell transmits a different source signal in a time and / or frequency multiplexing manner. These two alternatives... Figure 2A and Figure 2B As shown in the figure, Figure 2B An example of an SFN transmission strategy for TRP across cells is shown, and Figure 2A An example of a sequential (by TRP) transmission strategy across cells is shown. The two transmission strategies shown for transmitting the reference signal may be referred to herein as transmission modes, and more specifically as multi-TRP (or SFN) transmission mode and single-TRP transmission mode. As will be understood, Figure 2A and Figure 2B The source signals of the transmissions depicted can all be of the same type, such as SSB, but can have different identifiers or indices, such as SSB#0 to SSB#N.

[0065] exist Figure 2B In the example, each of the source signals S-RS#0 to S-RS#N is physically transmitted by each of the multiple TRPs in the cell. TRPs can cycle through different source signals. For example, at a first time, all TRPs can transmit the first signal (e.g., S-RS#0), then at a second time, all TRPs can transmit the second signal (e.g., S-RS#1), and so on. Conversely, in Figure 2AIn this process, each of the source signals S-RS#0 to S-RS#M is transmitted by a corresponding TRP (and only one) within the cell. For example, S-RS#0 and S-RS#1 are transmitted by TRP1, and S-RS#2 and S-RS#3 are transmitted by TRP2. Figure 2A and Figure 2B The example shows four TRPs, TRP1-TRP4. However, it should be understood that fewer or more TRPs may exist. Furthermore, the number of source signals shown in each figure is merely an example, and more or fewer source signals may be used.

[0066] Since the number of available source signals (e.g., SSBs) may be limited, selection can be performed frequently. Figure 2B The SFN transmission strategy, especially in cells with more than two or three TRPs, may be the only viable option. However, the use of the SFN transmission strategy (such as...) Figure 2B The detection and reception of a target reference signal (e.g., TRS) can be problematic. This is because the source signal (e.g., SSB) transmitted in SFN mode does not actually share the same channel characteristics as the target reference signal (e.g., TRS), which is transmitted on a per-TRP basis, and for that target reference signal, the source signal can be identified as a QCL source. Therefore, the UE's preparation of the channel estimation filter based on the source signal reception can complicate the UE channel estimation of the target reference signal. This can be particularly problematic in SSB / TRS scenarios (where the target reference signal (i.e., TRS) is also the QCL source reference signal used for other signals (such as PDCCH, PDSCH, and other CSI-RS)) because it can adversely affect the UE's ability to receive those other signals.

[0067] While most of the discussion in this paper is built on the SSB and TRS, it should be understood that similar problems may occur when any QCL source reference signal is transmitted via the mTRP transmission strategy and the source reference signal is sent on a per-TRP basis as the target reference signal of the QCL source.

[0068] This specification presents various example mechanisms for facilitating signal reception in mTRP scenarios. As described herein, at least one parameter can be provided to the terminal device or UE, the value of which depends on whether the source reference signal is transmitted by a single TRP in the serving cell of the terminal device or by multiple TRPs. The terminal device can then determine a subset of one or more channel characteristics identified by QCL information based on the value of the at least one parameter. The terminal device can then use an estimate of the subset of channel characteristics when receiving a target reference signal whose source signal is a QCL source. As will be understood from the discussion herein, a “subset” can include all elements of a set, or some but not all elements of that set (i.e., an appropriate subset).

[0069] As will be explained below, in some examples, when the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell and a target reference signal is transmitted using a single TRP, for example, by default or through network configuration, a proper subset of the channel characteristics identified by the QCL information (e.g., by a given QCL-Type) can be utilized when receiving the target reference signal. Conversely, in some examples, when the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP and the target reference signal is also transmitted using a single TRP, the entire set of channel characteristics identified by the QCL information (e.g., by a given QCL-Type) can be utilized when receiving the target reference signal. For example, one or more channel characteristics identified by the QCL information may include average delay and Doppler shift (e.g., as in QCL-Type C), but when i) the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell and ii) the target reference signal is transmitted using a single TRP in the serving cell, the subset of channel characteristics may include average delay but not Doppler shift. This is because the average delay can be applied even when the source reference signal is transmitted via mTRP (since the signal can be transmitted simultaneously by each TRP). However, Doppler shift may not be applicable because the terminal device may be moving at different speeds (i.e., directions and rates) relative to different TRPs transmitting the reference signal. On the other hand, when i) the value of at least one parameter corresponds to the source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, a subset of the channel characteristics can include both the average delay and the Doppler shift (i.e., the entire set of characteristics identified by QCL-TypeC).

[0070] One or more channel characteristics identified by the QCL information may also include spatial receiver parameters, and when i) the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP in the serving cell and ii) the target reference signal is transmitted using a single TRP in the serving cell, the receive spatial parameters may be used in addition to the average delay and Doppler shift. Conversely, when i) the value of at least one parameter corresponds to a source reference signal transmitted by multiple TRPs in the serving cell and ii) the target reference signal is transmitted using a single TRP in the serving cell, a subset of the channel characteristics does not include the receive spatial parameters. As will be appreciated, the use of spatial receiver parameters may depend on whether the UE has multiple antennas / panels. This is because if the UE does not have multiple panels / antennas, it does not need to estimate or apply spatial receiver parameters.

[0071] As those skilled in the art will understand, in some scenarios, QCL information can identify more than one QCL-Type, such as QCL-TypeC {Doppler shift, average delay} and QCL-TypeD {spatial Rx parameters}. In such examples, the set of channel characteristics from which a subset is determined can be a set identified by one of the QCL-Types (e.g., Type C), or it can be a set of channel characteristics identified by multiple QCL-Types (e.g., Type C and Type D). For example, when the UE is unable to perform beamforming (and therefore QCL-TypeD is not applicable), the set of channel characteristics from which a subset is determined can be a set identified by one of the QCL-Types (e.g., QCL-Type C). However, when the UE is able to perform beamforming, the set of channel characteristics from which a subset is determined can be channel characteristics identified by both QCL-TypeC and QCL-TypeD.

[0072] Any suitable configuration information sent to the terminal device may include at least one parameter. For example, it may be included in at least one of the following: a) QCL information that identifies i) the source reference signal and ii) one or more channel characteristics associated with the source reference signal and that can be used to receive one or more target reference signals, b) configuration information for the source reference signal, or c) configuration information for the target reference signal.

[0073] At least one parameter can take any suitable form. For example, at least one parameter can be a parameter whose value directly indicates to the terminal device, for example, whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell. For example, a value such as "1" or "true" can indicate that the source reference signal is transmitted by multiple TRPs in the serving cell, and a value such as "0" or "false" can indicate that the source reference signal is transmitted by a single TRP in the serving cell, not by multiple TRPs. Of course, it should be understood that a value such as "1" or "true" can indicate that the source reference signal is transmitted by a single TRP in the serving cell, and a value such as "0" or "false" can indicate that the source reference signal is transmitted by multiple TRPs in the serving cell. In examples such as these, the parameter can be referred to as, for example, the 'S-RS-mTRP-Info' parameter, the 'S-RS-SFN-Info' parameter, or the 'S-RS-Txmode' parameter.

[0074] In other examples, at least one parameter may include a parameter whose value indicates to the terminal device whether the transmission mode of the target reference signal (e.g., mTRP transmission or single TRP transmission) is the same as the transmission mode of the source reference signal. In such examples, configuration information for the target reference signal may include this parameter. A first value of the parameter may indicate that the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, and a second value of the parameter may indicate that the transmission mode of the target reference signal is different from the transmission mode of the source reference signal. It should be understood that in a scenario where the target reference signal is transmitted only in single TRP transmission mode, the parameter with the first value indicates that the source reference signal is also transmitted using single TRP mode. Conversely, the parameter with the second value indicates that the source reference signal is transmitted using mTRP transmission mode. In other example implementations, the target reference signal may be transmitted using, for example, a single TRP transmission mode or an mTRP transmission mode selected by the network. In those specific implementations where the value of the parameter indicates whether both the source and the target are using the same transmission mode, at least one parameter may include a second parameter that enables the terminal device to determine whether the mTRP transmission mode is being used for the source or the target. For example, the value of the second parameter can indicate whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell. In such an example, at least one of the configuration information or QCL information for the source reference signal may include the second parameter. Alternatively, the value of the second parameter can indicate whether the target reference signal is transmitted by a single TRP or multiple TRPs in the serving cell. In such an example, the configuration information for the target reference signal may include the second parameter.

[0075] As will be understood, in an example where the value of at least one parameter indicates to the terminal device whether the transmission mode of the target reference signal is the same as that of the source reference signal, if the parameter (and the second parameter, where appropriate) corresponds to the source reference signal being transmitted via mTRP and the target reference signal being transmitted via single TRP, then a different subset of channel characteristics can be applied when receiving the target reference signal compared to if the parameter (and the second parameter, where appropriate) corresponds to both the source and target reference signals being transmitted via single TRP. For example, when transmitting two signals using a single TRP transmission mode, all channel characteristics indicated by the QCL information (or a given QCL-Type in the QCL information) can be utilized, while when the source signal is transmitted using the mTRP transmission mode but the target reference signal is not, some, but not all (i.e., a proper subset) of the channel characteristics indicated by the QCL information (or a given QCL-Type in the QCL information) can be utilized. In the example where this parameter (and the second parameter, where appropriate) corresponds to both the source reference signal and the target reference signal transmitted via the mTRP transmission mode, the terminal device may use all channel characteristics indicated by the QCL information (or a given QCL-Type in the QCL information).

[0076] In other examples, the value of at least one parameter may indicate a subset of one or more channel characteristics identified in the QCL information that can be used to receive the target reference signal. In these examples, at least one parameter may be a parameter included in the configuration information for the source reference signal or the configuration information for the target reference signal.

[0077] As an example of the value of at least one parameter indicating a subset of one or more channel characteristics identified in the QCL information, the at least one parameter may include a parameter whose value may indicate a QCL-subtype corresponding to a subset of multiple channel characteristics corresponding to the QCL-Type included in the QCL information. The subset of channel characteristics used by the UE to receive the target reference signal may be a subset corresponding to a QCL subtype. For example, if the QCL information indicates QCL-Type C, the parameter may indicate QCL-subtype Cb. Therefore, although QCL-Type C indicates Doppler shift and average delay, QCL-subtype Cb may correspond only to the average delay. In such examples, if the source reference signal is transmitted using mTRP mode, a QCL-subtype may be indicated, and the terminal device may utilize only the subset of parameters corresponding to the subtype (instead of all characteristics indicated by the QCL-Type).

[0078] As another example of the value of at least one parameter indicating a subset of one or more channel characteristics identified in the QCL information, the at least one parameter may include a parameter whose value indicates the characteristics to be applied in the QCL-type to determine a bitmap or mask of the subset. The bitmap or mask may be, for example, a vector of values, where a first value (e.g., "0") at a given location in the bitmap or mask indicates that the channel characteristic in the QCL-type at the location corresponding to the given location should not be used by the terminal device, while a second value (e.g., "1") indicates that the channel characteristic in the QCL-type at the location corresponding to the given location should be used by the terminal device. For example, if the QCL-Type is QCL-TypeA (i.e., {Doppler shift, Doppler spread, average delay, delay spread}), then the bitmap or mask {0010} may indicate that only the average delay should be used. Similarly, if the QCL-Type is QCL-TypeC (i.e., {Doppler shift, average delay}), then the bitmap or mask {01} may indicate that only the average delay should be used.

[0079] As will be understood from the examples described herein, in some implementations, the source reference signal may be a reference signal broadcast for initial access. In 5G, the SSB is used for this purpose. This may also be the case in future generations (such as 6G), but it is also possible that different reference signals may be used for this purpose instead. In some implementations, the target reference signal may be a reference signal used to track the channel in the time and frequency domains when the terminal is actively communicating within the serving cell. In 5G, such a signal is called a TRS (Tracking Reference Signal), but it should be understood that different (or at least differently named) signals may be used for this purpose in future networks.

[0080] Figure 3 It is a message stream that illustrates various messages that can be transmitted and operations that can be performed according to various embodiments of the technology described herein. Figure 3 A specific implementation is shown where the source signal is an SSB and the target reference signal is a TRS. However, it should be understood that the techniques described herein can be applied to other combinations of source and target reference signals. Therefore, it is not intended to equate the reference signal with other meanings. Figure 3 The operations and messages discussed are limited to the specific example where the source signal is an SSB and the target reference signal is a TRS. Conversely, those skilled in the art will understand that these operations and messages can be equally applied to other signal types.

[0081] The message flow is shown relative to the terminal device and network nodes (such as gNB, or more generally, base station). Although in Figure 1Although not shown, it should be understood that network nodes can utilize more than one TRP to transmit signals. Furthermore, it should be understood that network nodes can be distributed across more than one network / virtual entity (e.g., a centralized unit (CU), a distributed unit (DU), and a remote radio head (RRH)) hosting different network functions or protocol layers.

[0082] In operation S3.1, the network node transmits a source reference signal. More specifically, in this example, the network node broadcasts an SSB, which is an example of a reference signal used by the terminal device for initial access or handover. As will be understood, the network node may transmit multiple source reference signals and / or may transmit one or more source reference signals via mTRP transmission mode or single TRP transmission mode.

[0083] In operation S3.2, the terminal device detects the source signal (i.e., SSB in this example).

[0084] In operation S3.3, the terminal device sends an indication of the source signal to the network node. When the source signal is an SSB, sending an indication of the SSB to the network node can be part of the initial access procedure or after initial access, for example, via a Layer 1 Reference Signal Received Power (RSRP) report.

[0085] In operation S3.4, the network node sends QCL information to the terminal device. This can be performed in response to receiving or otherwise receiving an indication from the terminal device of an SSB. The QCL information identifies the source reference signal, which in this example is the SSB indicated by the terminal device in S3.3. The QCL information also indicates one or more channel characteristics associated with the source reference signal and can be used to receive one or more target reference signals, the source signal being the QCL source of the one or more target reference signals. The QCL information can be a Transmission Configuration Indicator (TCI) state. The TCI state identifies the source signal, in this case, the SSB. Furthermore, the TCI state identifies one or more QCL-Types, which indicate one or more channel characteristics that can be used to receive the target reference signal (the source signal being the QCL source of the target reference signal). Additionally, the TCI state may include the identifier and bandwidth portion of the associated cell. The indicated SSB's TCI state can be provided to the terminal device as part of RRC signaling along with several other TCI states for other reference signals.

[0086] In some examples, during operation S3.5, the network node may send configuration information for the source reference signal to the terminal device. However, in other examples, configuration information for the source reference signal may not be sent. For example, before the terminal device has transitioned to the RRC connected state, it may not receive any configuration information for the source signal (such as the SSB). In other examples, before the terminal device has transitioned to the RRC connected state, it may receive configuration information for the source signal (such as the SSB) via a System Information Block (SIB) (e.g., via SIB1). In other examples, such as when the terminal device transitions to or is already in the RRC connected state, some configuration information for the source reference signal (SSB or another source signal) may be sent to the terminal device.

[0087] In operation S3.6, the network node sends configuration information for the target reference signal to the terminal device. This configuration information identifies the source signal. Based on this identification, the terminal device can refer to the QCL information of the source signal received in S3.4 to identify the channel characteristics associated with the source reference signal and that can be used to receive the target reference signal. In some examples, the configuration information for the target reference signal indicates the TCI state, which identifies the source reference signal (SSB in this example). In the 5G context (and possibly in future generations), the TRS configuration information can consist of a parameter structure of 'NZP-CSI-RS-ResourceSet' (where the parameter of 'TRS-info' is set to "true") and one or more parameter structures of NZP-CSI-RS-Resource, one for each NZP-CSI-RS-Resource identified in 'NZP-CSI-RS-ResourceSet'. Here, the parameter identifying 'TCI-StateId' is included in the parameter structure of each NZP-CSI-RS-Resource. In some examples, the configuration information for the target reference signal may not indicate the source reference signal. For instance, the source reference signal for a specific target signal (such as PDCCH, PDSCH, PUCCH, or PUSCH) may be configured or indicated in some other way. For example, the source reference signal may be indicated by a combination of MAC and DCI, for example, within a unified TCI framework. For instance, the MAC CE command may be used to select up to eight active TCI states in the RRC-configured TCI states, and DCI may be used to indicate one of the active TCI states.

[0088] As described above, the network node provides at least one parameter, the value of which depends on whether the source reference signal is transmitted by a single Transmitter Receiver Point (TRP) or multiple TRPs in the serving cell of the terminal device. At least one of QCL information, configuration information for the source reference signal (e.g., SIB1), or configuration information for the target reference signal may include at least one parameter. The form of the at least one parameter and the information specifically indicated by the at least one parameter may be as described anywhere herein, at least in Figure 3 Before proceeding with the discussion. However, it should be understood that the at least one parameter is not limited to the specific examples described herein. Rather, the at least one parameter may take any suitable form that allows the terminal device to determine, based on the value of the at least one parameter, a subset of one or more channel characteristics identified in the QCL information for receiving the target reference signal.

[0089] In operation S3.7, network nodes broadcast source reference signals. As will be understood, this can be transmitted by a single TRP or sent by multiple TRPs in SFN mode.

[0090] In operation S3.8, the terminal device receives a source reference signal. This can be used in some examples of configuration information for the terminal device to receive the source reference signal.

[0091] In operation S3.9, the terminal device estimates the channel characteristics associated with the received source signal. These may include all of Doppler shift, Doppler spread, average delay, delay spread, and spatial Rx parameters (if the terminal device has multiple antennas). However, in other examples, the terminal device may estimate only a selection of characteristics. For example, the terminal device may estimate only those characteristics indicated in the QCL information (e.g., via one or more QCL-Types) or only a subset of the characteristics indicated in the QCL information, which is determined based on the value of at least one parameter depending on whether the source reference signal is transmitted by a single TRP or by multiple TRPs. Furthermore, the terminal device may estimate the channel characteristics associated with the received source signal after step S3.2.

[0092] In operation S3.10, the network node transmits a target reference signal. In the example shown, the target reference signal is a tracking reference signal (TRS).

[0093] In operation S3.11, the terminal device uses an estimate of a subset of channel characteristics indicated by the network in the QCL information (e.g., via QCL-Type) to receive the target reference signal. As described above, this subset is determined based on the value of at least one parameter, which depends on whether the source reference signal is transmitted by a single TRP or multiple TRPs in the terminal device's serving cell. For example, and as described above, when the value of at least one parameter corresponds to a source reference signal transmitted by a single TRP and the QCL relationship indicated by the QCL information is QCL-Type C and QCL-Type D, the terminal device can apply both the average delay and Doppler shift estimated from the source reference signal to receive the target reference signal. Furthermore, if the terminal device has multiple antennas / panels, the terminal device can additionally utilize the estimated Rx spatial parameters to receive the target reference signal. Conversely, when the value of at least one parameter corresponds to an SSB transmitted by multiple TRPs, the terminal device can apply the average delay but not the Doppler shift (nor the Rx spatial parameters).

[0094] As will be understood from the above discussion, in scenarios where the source reference signal can be transmitted in mTRP mode, the techniques described herein can facilitate the reception of the target reference signal by the terminal device. They may be particularly advantageous when the target reference signal itself is the source signal.

[0095] Figure 4 This demonstrates what can be achieved by a terminal device such as a reference. Figure 3 The flowchart illustrates the various operations performed by the terminal device. For further understanding, please refer to... Figure 4 Many of the operations described correspond in some respects to the reference. Figure 3 The operations described.

[0096] In operation S4.1, the terminal device receives quasi-co-located QCL information from a network node (such as a gNB or base station). This information identifies a source reference signal and one or more channel characteristics associated with the source reference signal that can be used to receive one or more target reference signals. The QCL information can be similar to the QCL information described with reference to S3.4. For example, it can include one or more QCL-Types. In such an example, it can be in the form of TCI states.

[0097] In operation S4.2, the terminal device receives at least one parameter whose value depends on whether the source reference signal is transmitted by a single Transmission Receiver Point (TRP) or multiple TRPs in the serving cell of the terminal device.

[0098] QCL information (see S4.1), configuration information of the source reference signal (where the source reference signal is received by the terminal device) or configuration information of the target reference signal (which can also be received at the terminal device (but...) Figure 4 At least one of the following (not depicted in the text) may include at least one parameter. It should be understood that in examples or specific implementations where the terminal device does not receive configuration information of the source reference signal, at least one of the QCL information or configuration information of the target reference signal may include at least one parameter.

[0099] The configuration information for the source reference signal (where the source reference signal is received) can be as described with reference to S3.5. As mentioned above, in some examples, the terminal device may not receive any configuration information for the source reference signal. The configuration information for the target reference signal can be as described with reference to S3.6. In some examples, the configuration information for the target reference signal may indicate a source reference signal quasi-co-located with the target reference signal. However, as mentioned above, in other examples, the source reference signal quasi-co-located with the target reference signal may be indicated or configured in some other way.

[0100] In operation S4.3, the terminal device receives a source reference signal from the network node. In some examples of configuration information for the terminal device to receive the source reference signal, this configuration information can be used to receive the source reference signal.

[0101] In operation S4.4, the terminal device determines a subset of one or more channel characteristics identified in the QCL information for receiving the target reference signal based on the value of at least one parameter.

[0102] In operation S4.5, the terminal device estimates the values ​​of one or more channel characteristics identified in the QCL information based on the received source signal. In some examples, the terminal device may estimate only the values ​​of a subset of channel characteristics. In other examples, the terminal device may estimate only the values ​​of those channel characteristics indicated in the QCL information. Alternatively, the terminal device may estimate the values ​​of all channel characteristics, regardless of the QCL information (or subset).

[0103] In operation S4.6, the terminal device receives the target reference signal from the network node using an estimate of a subset of the channel characteristics.

[0104] It should be understood, of course, that operations S4.3, S4.4, S4.5 and S4.6 can be similar to those described in reference operations S3.8 to S3.11.

[0105] In some examples, operations S4.4 and S4.5 may be performed in a different order than those depicted. For example, a subset of channel characteristics may be determined after the values ​​of the channel characteristics have already been estimated. In such examples, the terminal device may estimate only the values ​​of those channel characteristics indicated in the QCL information, or the values ​​of all channel characteristics, regardless of the QCL information. Similarly, additionally or alternatively, in some examples, operation S4.4 may be performed before operation S4.3.

[0106] Figure 5 This shows that it can be generated by network nodes (such as references) Figure 3 and Figure 4 A flowchart describing the various operations performed by the network nodes. For further understanding, please refer to... Figure 5 Many of the operations described can correspond to the reference. Figure 3 The operations described.

[0107] In S5.1 operation, network nodes operate the cell that provides services to terminal devices.

[0108] In operation S5.2, the network node transmits QCL information to the terminal device. This QCL information identifies a source reference signal and one or more channel characteristics associated with the source reference signal, which the terminal device can use to receive one or more target reference signals. The QCL information can be referenced elsewhere in this document, for example... Figure 3 and Figure 4 As described. Operation S5.2 can be similar to operation S3.4.

[0109] In operation S5.3, the network node sends a source reference signal. This can be repeated, for example, periodically. Therefore, as will be understood, the source reference signal can be sent multiple times throughout the process, for example, before S5.1 and / or after S5.4.

[0110] In operation S5.4, the network node transmits at least one parameter to the terminal device. The value of this parameter is set based on whether the source reference signal is transmitted by a single Transmitter Receiver Point (TRP) in the serving cell or by multiple TRPs. This can be described as described with reference to operation S4.2. Therefore, QCL information (see S5.2), configuration information for the source reference signal (wherein the source reference signal is transmitted by the network node), or configuration information for the target reference signal (which can also be transmitted by the network node (but in...) Figure 5 At least one of the following (not shown) may include at least one parameter. It should be understood that in examples or implementations where the network node does not transmit configuration information of the source reference signal, at least one of the QCL information or configuration information of the target reference signal may include at least one parameter.

[0111] As described herein, the value of at least one parameter is used by the terminal device to determine a subset of one or more channel characteristics identified in the QCL information, which can be used by the terminal device to receive a target reference signal. At least one parameter can be as described above with reference to the foregoing figures.

[0112] If understood, combined Figure 4 and Figure 5The described network nodes can utilize more than one TRP to transmit signals. Furthermore, as mentioned above, network nodes can be distributed across more than one network / virtual entity (e.g., central unit, CU, distributed unit, DU, remote radio head, RRH) hosting different network functions or protocol layers. It should also be understood that references... Figure 3 , Figure 4 and Figure 5 Some of the operations described may be performed in a different order than those depicted. Additionally or alternatively, some operations may be performed simultaneously. For example, if the QCL information includes at least one parameter, operations S5.2 and S5.4 may actually be a single operation (which could be operations S4.1 and S4.2).

[0113] Example configuration of the device Figure 6 It can be configured as an execution reference. Figures 1 to 5 A schematic diagram illustrating example configurations of the terminal device (UE) for various operations described.

[0114] The terminal device (UE) can communicate with a network node or base station, for example, via a suitable radio interface arrangement 805. The interface arrangement 805 can be provided, for example, by means of a radio component 805-2 (e.g., a transceiver) and an associated antenna arrangement 805-1. The antenna arrangement 805-1 can be arranged inside or outside the terminal device (UE). To enable beamforming, the antenna arrangement 805-1 includes multiple antennas. For example, some UEs may include twelve antenna elements, such as four panels, each panel having four cross-polarized antenna elements.

[0115] The terminal device UE includes a controller / control (or processing) device 80, which, in addition to performing any suitable combination of operations in conjunction with the terminal device UE described with reference to the foregoing FIGS, is also operable to control other components of the terminal device UE. Computer-readable code 802-2A may be stored on memory 802 and, when executed by processing device 801, causes control device 80 to perform any operations described herein with respect to the terminal device UE.

[0116] The example configuration of memory 802 and processing device 801 will be discussed in more detail below.

[0117] A terminal device (UE) can be, for example, a device that does not require human interaction, such as an entity involving machine-type communication (MTC). Alternatively, a terminal device (UE) can be a device designed for tasks involving human interaction, such as making and receiving telephone calls between users and streaming multimedia or providing other digital content to users. Non-limiting examples of terminal devices (UEs) include smartphones, laptops, smartwatches, tablets, e-readers, vehicle-based terminal devices (such as those installed in cars, buses, unmanned aerial vehicles (UAVs), airplanes, trains, or ships), or any type of terminal device that can be carried or worn by a user.

[0118] In cases where the terminal device (UE) is designed for human interaction, the user can control its operation via a suitable user input interface (UII) 804, such as a keypad, voice commands, a touchscreen, a tablet computer, or a combination thereof. A display 803, a speaker, and a microphone may also be provided. Furthermore, the UE may include connections to other devices and / or appropriate connectors (wired or wireless) for attaching external accessories (e.g., hands-free devices). The UE may also be associated with one or more motion sensors 806 for sensing motion of the mobile device (e.g., including or communicating with these motion sensors via short-range wired or wireless communication). The UE may also include other sensors, such as a GNSS unit.

[0119] Figure 7 This is a schematic diagram of an example configuration of a network node (NN). As mentioned above, a network node can be a base station, such as a gNodeB or gNB. In some examples, the network node may include a radio interface via which it communicates with the terminal device (UE). Therefore, the network node can also be a TRP. In such examples, such as... Figure 7 As shown, a network node may include a radio frequency antenna array 901 configured to receive and transmit radio frequency signals. Although the network node NN is shown as an array 901 with four antennas, this is merely illustrative. The number of antennas can vary from two to hundreds. The network node NN also includes a radio frequency interface circuit 903 configured to interface between the antennas 901 and the control device 90. The radio frequency interface circuit 903 may also be referred to as a transceiver.

[0120] The network node NN also includes one or more interfaces 909, through which the network node NN can communicate with the TRP, other base stations and other network entities (such as network entities in the core network).

[0121] The network node control device 90 can be configured to exchange information with other network elements via interface 909. Furthermore, the network node control device 90 can be configured to process signals from the radio frequency interface circuit 903 and control the radio frequency interface circuit 903 to generate appropriate RF signals to transmit information to the terminal device UE via a wireless communication link.

[0122] The network node control device 90 may include a processing device 902 and a memory 904. Computer-readable code 904-2A may be stored in the memory 904 and, when executed by the processing device 902, causes the control device 90 to perform any operations assigned to the aforementioned base station TRP1.

[0123] As described above, in some examples, network nodes can be distributed across more than one network / virtual entity (e.g., a centralized unit (CU), a distributed unit (DU), and a remote radio head (RRH)) hosting different network functions or protocol layers. Furthermore, it should be understood that the above... Figure 6 and 7 Each of the entities UE and NN shown in this application may include other elements that are not directly related to the processes and operations of concern in this application.

[0124] The components and features of the aforementioned apparatus / entity / device, as well as some further details of their alternatives, will now be described.

[0125] Control devices 80 and 90 may include processing devices 801 and 902 communicatively coupled to memories 802 and 904. Memories 802 and 904 have computer-readable instructions 802-2A and 904-2A stored thereon, which, when executed by processing devices 801 and 902, cause control devices 80 and 90 to perform various operations described herein. In some cases, control devices 80 and 90 may be collectively referred to as “devices”.

[0126] Processing devices 801 and 902 can have any suitable composition and can include one or more processors 801A and 902A of any suitable type or combination of suitable types. For example, processing devices 801 and 902 can be programmable processors that interpret computer program instructions 802-2A and 904-2A and process data. Processing devices 801 and 902 can include multiple programmable processors. Alternatively, processing devices 801 and 902 can be programmable hardware, for example, with embedded firmware. Processing devices 801 and 902 can be referred to as processing devices. Processing devices 801 and 902 can alternatively or additionally include one or more application-specific integrated circuits (ASICs). In some cases, processing devices 801 and 902 can be referred to as computing devices.

[0127] Processing devices 801 and 902 are coupled to and operable to read data from and write data to memory 802 and 904 (which may be referred to as one or more storage devices). Memory 802 and 904 may include a single memory cell or multiple memory cells on which computer-readable instructions (or code) 802-2A and 904-2A are stored. For example, memory 802 and 904 may include both volatile memory 802-1 and non-volatile memory 802-2. For example, computer-readable instructions / program code 802-2A and 904-2A may be stored in non-volatile memory 802-2 and 904-2, and may be executed by processing devices 801 and 902 using volatile memory 802-1 and 904-1 for data or temporary storage of data and instructions. In some examples, the transmission buffer 802-1 B of the terminal device UE can be constituted by the volatile memory 802-1 of the UE control device 80. Examples of volatile memory include RAM, DRAM, and SDRAM. Examples of non-volatile memory include ROM, PROM, EEPROM, flash memory, optical storage devices, magnetic storage devices, etc. Memory can generally be referred to as a non-transitory computer-readable storage medium.

[0128] In addition to encompassing both non-volatile and volatile memory, the term "memory" can also encompass only one or more volatile memories, only one or more non-volatile memories, or one or more volatile memories and one or more non-volatile memories.

[0129] Computer-readable instructions / program codes 802-2A and 904-2A can be pre-programmed into control devices 80 and 90. Alternatively, computer-readable instructions 802-2A and 904-2A can reach control devices 80 and 90 via electromagnetic carrier signals, or can be copied from a physical entity 1000 such as a computer program product, a memory device, or a recording medium such as a CD-ROM or DVD, examples of which are shown in [reference needed]. Figure 8 As shown in the diagram. Computer-readable instructions 802-2A and 904-2A can provide logic and routines that enable a physical device / apparatus to perform the functions described above. A combination of computer-readable instructions stored on memory (of any type described above) can be referred to as a computer program product.

[0130] Embodiments of the techniques described herein can be implemented as software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and / or hardware can reside on memory or any computer medium. In example embodiments, the application logic, software, or instruction set is maintained on any of a variety of conventional computer-readable media. In the context of this document, "memory" or "computer-readable medium" can be any medium or component that can contain, store, communicate, propagate, or transmit instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

[0131] In relevant contexts, references to "computer-readable storage medium," "computer program product," "tangible embodiment of a computer program," or "processor" or "processing device" should be understood to encompass not only computers with different architectures (such as single / multiprocessor architectures and sequencer / parallel architectures) but also special-purpose circuits (such as field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), signal processing devices, and other devices). References to computer programs, instructions, code, etc., should be understood to express software (such as programmable content of hardware devices) used for programmable processor firmware as instructions for the processor or as configuration or configuration settings for fixed-function devices, gate arrays, programmable logic devices, etc. If necessary, the different functions discussed herein may be executed in different orders and / or simultaneously with each other. Furthermore, one or more of the aforementioned functions may be optional or may be combined, if required. Similarly, it should be understood that the flowcharts described herein are merely examples, and the various operations depicted therein may be omitted, reordered, and / or combined.

[0132] Although the methods and apparatus have been described in conjunction with New Radio (NR) networks, it should be understood that they are not limited to such networks and are applicable to a wide variety of radio networks.

[0133] Although various aspects of the methods and apparatus described herein are set forth in the independent claims, other aspects may include other combinations of features from the described embodiments and / or dependent claims with features of the independent claims, and not just those expressly set forth in the claims.

[0134] It should also be noted that while various examples have been described above, these descriptions should not be considered limiting. Rather, several changes and modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A terminal device, comprising: A component for receiving quasi-co-located QCL information, the quasi-co-located QCL information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; A component for receiving at least one parameter, the value of which depends on whether the source reference signal is transmitted by a single Transmit Receive Point (TRP) or multiple TRPs in the serving cell of the terminal device; Components for receiving the source reference signal; A component for determining a subset of one or more channel characteristics identified by the QCL information based on the value of the at least one parameter, for receiving a target reference signal indicated as quasi-co-located with the source reference signal; A component for estimating the values ​​of the subset of channel characteristics based on the received source reference signal; as well as A component for receiving the target reference signal using the estimated values ​​of the subset of channel characteristics.

2. The terminal device according to claim 1, wherein the one or more channel characteristics identified by the QCL information include average delay and Doppler frequency shift. And among them: If i) the value of the at least one parameter corresponds to the source reference signal transmitted by a plurality of TRPs in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then the subset of channel characteristics includes the average delay and excludes the Doppler shift.

3. The terminal device according to claim 2, wherein: If i) the value of the at least one parameter corresponds to the source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then the subset of channel characteristics includes the average delay and the Doppler shift.

4. The terminal device according to claim 1, wherein the one or more channel characteristics identified by the QCL information include average delay, Doppler shift, and spatial receiver parameters. And among them: If i) the value of the at least one parameter corresponds to the source reference signal transmitted by a plurality of TRPs in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then the subset of channel characteristics includes the average delay and excludes the Doppler shift and the spatial reception parameter.

5. The terminal device according to claim 4, wherein: If i) the value of the at least one parameter corresponds to the source reference signal transmitted by a single TRP in the serving cell, and ii) the target reference signal is transmitted using a single TRP in the serving cell, then the subset of channel characteristics includes the average delay, the Doppler shift, and the spatial receiver parameter.

6. The terminal device according to any of the preceding claims, wherein at least one of the QCL information, the configuration information for the source reference signal, or the configuration information for the target reference signal includes the at least one parameter.

7. The terminal device according to any preceding claim, wherein the at least one parameter includes a parameter, Furthermore, the value of the parameter indicates to the terminal device whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell.

8. The terminal device according to claim 6, wherein the at least one parameter includes a parameter, And among them: The value of the parameter indicates to the terminal device whether the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, wherein the transmission mode of the source reference signal is one of the following: the source reference signal is transmitted by a single TRP in the serving cell, or the source reference signal is transmitted by multiple TRPs in the serving cell, and The configuration information used for the target reference signal includes the parameters.

9. The terminal device according to claim 8, wherein the at least one parameter includes a second parameter. And among them: The value of the second parameter indicates whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell, and At least one of the QCL information, the configuration information of the source reference signal, or the configuration information of the target reference signal includes the second parameter.

10. The terminal device according to claim 6, wherein the at least one parameter includes a parameter, And among them: The value of the parameter indicates the subset of one or more channel characteristics identified in the QCL information that can be used to receive the target reference signal, and The configuration information for the source reference signal or the configuration information for the target reference signal includes the parameters.

11. The terminal device according to claim 10, wherein: The QCL information indicates the QCL type corresponding to multiple channel characteristics associated with the source reference signal. The value of the parameter indicates a QCL subtype corresponding to a subset of the plurality of channel characteristics corresponding to the QCL type, and The subset of channel characteristics determined based on the value of the parameter is the subset of the plurality of channel characteristics corresponding to the QCL type.

12. The terminal device according to claim 10, wherein: The QCL information indicates the QCL type corresponding to multiple channel characteristics associated with the source reference signal. The value of the parameter represents a bitmap or mask. The terminal device includes components for applying the bitmap or the mask to the plurality of channel characteristics to determine the subset of the plurality of channel characteristics corresponding to the QCL type, and The subset of channel characteristics determined based on the value of the parameter is the subset of the plurality of channel characteristics corresponding to the QCL type.

13. The terminal device according to any of the preceding claims, wherein: The source reference signal is the reference signal broadcast for initial access, and The target reference signal is a reference signal used to track the channel in the time and frequency domains when the terminal is actively communicating within the serving cell.

14. The terminal device according to any of the preceding claims, wherein the source reference signal is a synchronization signal block (SSB) and the target reference signal is a channel state information reference signal (CSI-RS).

15. The terminal device according to claim 14, wherein the target reference signal is a tracking reference signal.

16. The terminal device according to any preceding claim, wherein the QCL information includes a Transmission Configuration Indicator (TCI) state, and the target reference signal is indicated as quasi-co-addressable with the source reference signal by identifying the TCI state.

17. A network node, comprising: Components used in cells to operate service terminal equipment; A component for transmitting quasi-co-located QCL information to the terminal device, the quasi-co-located QCL information identifying a source reference signal and one or more channel characteristics associated with the source reference signal; Components used for transmitting the source reference signal; A component for transmitting at least one parameter to the terminal device, the value of which is set according to whether the source reference signal is transmitted by a single Transmit Receive Point (TRP) or multiple TRPs in the serving cell; as well as Components for transmitting a target reference signal that is indicated to be quasi-co-located with the source reference signal.

18. The network node of claim 17, wherein the value of the at least one parameter is used by the terminal device to determine a subset of the one or more channel characteristics identified in the QCL information, the subset being usable by the terminal device for receiving the target reference signal.

19. The network node according to claim 17 or 18, wherein at least one of the QCL information, the configuration information for the source reference signal, or the configuration information for the target reference signal includes the at least one parameter.

20. The network node according to any one of claims 17 to 19, wherein the at least one parameter includes a parameter, Furthermore, the value of the parameter indicates to the terminal device whether the source reference signal is transmitted by a single TRP or multiple TRPs in the serving cell.

21. The network node of claim 19, wherein the at least one parameter includes a parameter, Furthermore, the configuration information of the target reference signal includes the parameter, and the value of the parameter indicates to the terminal device whether the transmission mode of the target reference signal is the same as the transmission mode of the source reference signal, wherein the transmission mode of the source reference signal is one of the following: the source reference signal is transmitted by a single TRP in the serving cell, or the source reference signal is transmitted by multiple TRPs in the serving cell.

22. The network node of claim 19, wherein the at least one parameter includes a parameter, And among them: The QCL information indicates the QCL type corresponding to multiple channel characteristics associated with the source reference signal; as well as The configuration information for the source reference signal or the configuration information for the target reference signal includes the parameters, and The value of the parameter indicates a QCL subtype corresponding to a subset of the plurality of channel characteristics corresponding to the QCL type.

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