Patent Description:
The following abbreviations are herewith defined, some of which are referred to within the following description: Third Generation Partnership Project (3GPP), European Telecommunications Standards Institute (ETSI), Frequency Division Duplex (FDD), Frequency Division Multiple Access (FDMA), Long Term Evolution (LTE), New Radio (NR), Very Large Scale Integration (VLSI), Random Access Memory (RAM), Read-Only Memory (ROM), Erasable Programmable Read-Only Memory (EPROM or Flash Memory), Compact Disc Read-Only Memory (CD-ROM), Local Area Network (LAN), Wide Area Network (WAN), Personal Digital Assistant (PDA), User Equipment (UE), Uplink (UL), Evolved Node B (eNB), Next Generation Node B (gNB), Downlink (DL), Central Processing Unit (CPU), Graphics Processing Unit (GPU), Field Programmable Gate Array (FPGA), Dynamic RAM (DRAM), Synchronous Dynamic RAM (SDRAM), Static RAM (SRAM), Liquid Crystal Display (LCD), Light Emitting Diode (LED), Organic LED (OLED), Multiple-Input Multiple-Output (MIMO), Sounding Reference Signal (SRS), Code division multiplexing (CDM), Physical Resource Block (PRB), Integrated Access and Backhaul (IAB) , Time division multiplexing (TDM), Physical Downlink Shared Channel (PDSCH), Physical Uplink Shared Channel (PUSCH), Physical Downlink Control Channel (PDCCH), Physical Uplink Control Channel (PUCCH), Space Division Multiplexing (SDM), Frequency Division Multiplexing (FDM), reference signal (RS), Channel-state information reference signal (CSI-RS), synchronization signal block (SSB), Transmission Configuration Indication (TCI), Downlink Control Information (DCI), Radio Resource Control (RRC), Medium Access Control (MAC), Control Element (CE), logical channel identification (LCID), Transmission Configuration Indication (TCI), bandwidth part (BWP), subcarrier spacing (SCS), phase tracking reference signal (PTRS) and demodulation signal (DMRS).

<FIG> shows a two-hop IAB (Integrated Access and Backhaul) system. <FIG> shows three types of nodes: parent IAB node <NUM>, child IAB node <NUM> and UE <NUM>. The link between the parent IAB node <NUM> and the child IAB node <NUM> is referred to as parent backhaul link. The link between the child IAB node <NUM> and its served UE <NUM> is referred to as access link. Technically, the UE <NUM> shown in <FIG> may also be a child IAB node that serves another UE.

An IAB node is a kind of gNB which can perform both gNB and UE function. When it is started, it will behave like a UE to do cell search and find suitable cell to associate with. After it is connected to the network, it can behave like a gNB to serve UEs by transmitting system broadcast information and scheduling UEs. Both the parent IAB node and the child IAB node in <FIG> can be considered as an IAB node.

In the IAB system shown in <FIG>, when Space Division Multiplexing (SDM) or Frequency Division Multiplexing (FDM) is adopted between the parent backhaul link and the access link, power imbalance will happen due to different capabilities of the IAB node(s) and the UE. In case of SDM, the downlink (DL) signal that the child IAB node <NUM> receives from the parent IAB node <NUM> and the uplink (UL) signal that the child IAB node <NUM> receives from the UE <NUM> are multiplexed by different spatial layers. To enable efficient spatial domain multiplexing, it is preferable that the power level of the downlink signal and the power level of the uplink signal are comparable (at approximately the same level). In case of SDM, the downlink (DL) signal that the child IAB node <NUM> receives from the parent IAB node <NUM> and the uplink (UL) signal that the child IAB node <NUM> receives from the UE <NUM> are multiplexed by different frequency domain resources while sharing a same power amplifier. To enable efficient frequency domain multiplexing, it is preferable that the power level of the downlink signal and the power level of the uplink signal are comparable.

In a Multiple-Input Multiple-Output (MIMO) scenario especially in high frequency band, a plurality of beams can be used to transmit signals between the parent IAB node <NUM> and the child IAB node <NUM>, and between the child IAB node <NUM> and the UE <NUM>. <FIG> shows that one beam, i.e., UL beam i, is used to transmit UL signals from the UE <NUM> to the child IAB node <NUM>. In addition, <FIG> shows that two beams, i.e., DL beam <NUM> and DL beam N, can be used to transmit DL signals from the parent IAB node <NUM> to the child IAB node <NUM>, in which the DL beam <NUM> may be the preferred beam selected by the child IAB node <NUM>. The beam is generated by weighting values in the multiple antenna elements. Different beams correspond to different strongest transmission or reception directions. For a specific beam, there will be different channel gain values at different directions. At any of the parent IAB node <NUM>, the child IAB node <NUM> and the UE <NUM>, each beam corresponds to a spatial domain filter.

As an example, the power level of the received downlink signal using DL beam <NUM> ranges from -144dBm to -44dBm, while the power level of the received uplink signal using UL beam i ranges from -202dBm to -60dBm. In this condition, the maximum received power level that the child IAB node <NUM> can configure for the uplink signal using UL beam i is -60dBm. If the received power level of the downlink signal using DL beam <NUM> is more than -60dBm, for example, -50dBm, it is impossible for the child IAB node <NUM> to configure the received power level of the uplink signal using UL beam i to a level that is comparable to (i.e. approximately the same as) the received power level of the downlink signal using DL beam <NUM>. The difference between of the maximum received power level of the downlink signal using DL beam <NUM> and the maximum received power level of the uplink signal using UL beam i may be referred to as "power gap" (see <FIG>).

<FIG> shows the power gap between the maximum received power level of the downlink signal based on DL beam <NUM> and the maximum received power level of the uplink signal based on UL beam i. Both the maximum power levels refer to the receiving power at the child IAB node <NUM>. Because of the power gap, the child IAB node <NUM> may not be able to configure the power level of uplink signal from the UE <NUM> to the child IAB node <NUM> using UL beam i to a level that is approximately the same as the power level of the downlink signal from the parent IAB node <NUM> to the child IAB node <NUM> using DL beam <NUM> if the power level of the downlink signal using DL beam <NUM> is configured to be more than the maximum power level of the uplink signal using UL beam i.

<CIT> discusses a method of a UE for a beam failure recovery procedure.

<NPL> which discusses physical layer enhancements for NR IAB.

<CIT> discloses a method for enabling a base station and terminal to efficiently communicate.

<CIT> discloses a power determination method and apparatus.

<CIT> discloses a method for reporting power headroom.

Claims <NUM> and <NUM> each define a method. Claims <NUM> and <NUM> each define an apparatus.

Methods and apparatuses for power control are disclosed.

In one embodiment, a method comprises: receiving a first signaling indicating one or multiple power values for a downlink reception from a node, each power value being associated with a spatial domain filter, and determining a power value for the downlink reception from the node.

In some embodiment, the power value is a power offset that indicates that a power level to be reduced, or an absolute transmitting power level, or an absolute receiving power level. In other embodiment, the power values associated with one or multiple spatial domain filters are configured by RRC signaling or by MAC CE signaling, or any combination thereof. In particular, the power value for PDSCH scheduled by a DCI is determined by a TCI state in the DCI or a default TCI state or a default TCI state set, and the TCI state is used to determine the spatial domain filter.

In some embodiment, both the default TCI state and the default TCI state set are selected from a TCI state set configured by RRC signaling or MAC CE signaling or DCI 2_0 or DCI 2_2 or DCI 2_3 or any combination thereof. In other embodiment, the power value for PDSCH is based on the smallest or the largest value among power values for all the TCI states in the default TCI state set.

In some embodiment, he power value for PDCCH or for CSI-RS is determined by a TCI state in RRC signaling or MAC CE signaling or any combination thereof.

In some embodiment, both the power value and the TCI state corresponding to the spatial domain filter are indicated in DCI to determine the power value for scheduled PDSCH. Moreover, the number of bits for power value indication in the DCI is configured by RRC signaling.

In some embodiment, an apparatus comprises: a receiver that receives first signaling indicating one or multiple power values for a downlink reception from a node, each power value being associated with a spatial domain filter, and a processor that determines a power value for the downlink reception from the node.

In some embodiment, a method comprises: transmitting a first signaling indicating one or multiple power values for a downlink reception from a node, each power value being associated with a spatial domain filter. In other embodiment, an apparatus comprises: a transmitter that transmits a first signaling indicating one or multiple power values for a downlink reception from a node, each power value being associated with a spatial domain filter.

In some embodiment, a method comprises: receiving a first signaling indicating a set of RS resources, wherein each RS resource corresponds to a spatial domain filter; receiving a second signaling indicating reporting for power values for all of or part of RS resources contained in the set of RS resources; and reporting power value for at least one of the RS resources. In other embodiment, an apparatus comprises: a receiver that receives a first signaling indicating a set of RS resources, wherein each RS resource corresponds to a spatial domain filter, and receives a second signaling indicating reporting for power values for all of or part of RS resources contained in the set of RS resources; and a transmitter that reports power value for at least one of the RS resources.

In some embodiment, a method comprises: transmitting a first signaling indicating a set of RS resources, wherein each RS resource corresponds to a spatial domain filter; transmitting a second signaling indicating reporting for power values for all of or part of RS resources contained in the set of RS resources; and receiving power value for at least one of the RS resources. In other embodiment, an apparatus comprises: a transmitter that transmits a first signaling indicating a set of RS resources, wherein each RS resource corresponds to a spatial domain filter, and transmits a second signaling indicating reporting for power values for all of or part of RS resources contained in the set of RS resources; and a receiver that receives power value for at least one of the RS resources.

Understanding that these drawings depict only some embodiments, and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:.

Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may generally all be referred to herein as a "circuit", "module" or "system". Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine-readable code, computer readable code, and/or program code, referred to hereafter as "code".

Certain functional units described in this specification may be labeled as "modules", in order to more particularly emphasize their independent implementation. For example, a module may be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components.

Nevertheless, the executables of an identified module need not be physically located together, but, may include disparate instructions stored in different locations which, when joined logically together, include the module and achieve the stated purpose for the module.

Similarly, operational data may be identified and illustrated herein within modules and may be embodied in any suitable form and organized within any suitable type of data structure. This operational data may be collected as a single data set, or may be distributed over different locations including over different computer readable storage devices.

The computer readable storage medium may be a storage device storing code. The storage device may be, for example, but need not necessarily be, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

A non-exhaustive list of more specific examples of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash Memory), portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object-oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or the like, and/or machine languages such as assembly languages. The code may be executed entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the very last scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid any obscuring of aspects of an embodiment.

This code may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which are executed via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions or acts specified in the schematic flowchart diagrams and/or schematic block diagrams for the block or blocks.

The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices, to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function or act specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices, to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code executed on the computer or other programmable apparatus provides processes for implementing the functions or acts specified in the flowchart and/or block diagram block or blocks.

<FIG> depicts an embodiment of a wireless communication system <NUM> for power control. In one embodiment, the wireless communication system <NUM> includes parent IAB nodes <NUM>, child IAB nodes <NUM> and UEs <NUM>. Even though only one parent IAB node <NUM>, one child IAB node <NUM> and one UE <NUM> are depicted in <FIG>, one skilled in the art will recognize that any number of parent IAB nodes <NUM>, child IAB nodes <NUM> and UEs <NUM> may be included in the wireless communication system <NUM>.

In the parent backhaul link between the parent IAB node <NUM> and the child IAB node <NUM>, the parent IAB node functions as a base unit <NUM> while the child IAB node functions as a remote unit <NUM>. In the access link between the child IAB node <NUM> and the UE <NUM>, the child IAB node functions as a base unit <NUM> while the UE functions as a remote unit <NUM>. For any link between a base unit <NUM> and a remote unit <NUM>, the base unit <NUM> would be responsible to control the communication between the base unit <NUM> and the remote unit <NUM>.

In one embodiment, the remote units <NUM> may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs), tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle on-board computers, network devices (e.g., routers, switches, modems), or the like. The remote units <NUM> may be referred to as subscriber units, mobiles, mobile stations, users, terminals, mobile terminals, fixed terminals, subscriber stations, user equipment (UE), user terminals, a device, or by other terminology used in the art.

The base units <NUM> may be distributed over a geographic region. In certain embodiments, a base unit <NUM> may also be referred to as an access point, an access terminal, a base, a base station, a Node-B, an eNB, a gNB, a Home Node-B, a relay node, a device, or by any other terminology used in the art. The base units <NUM> are generally part of a radio access network that includes one or more controllers communicably coupled to one or more corresponding base units <NUM>. These and other elements of radio access and core networks are not illustrated, but are well known generally by those having ordinary skill in the art.

In one implementation, the wireless communication system <NUM> is compliant with NR (<NUM>). More generally, however, the wireless communication system <NUM> may implement some other open or proprietary communication protocol.

The base units <NUM> may serve a number of remote units <NUM> within a serving area.

<FIG> depicts one embodiment of an apparatus <NUM> that may be used for power control. The apparatus <NUM> includes one embodiment of the remote unit <NUM>. Furthermore, the remote unit <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, a display <NUM>, a transmitter <NUM>, and a receiver <NUM>. In some embodiments, the input device <NUM> and the display <NUM> are combined into a single device, such as a touch screen. In certain embodiments, the remote unit <NUM> may not include any input device <NUM> and/or display <NUM>. In various embodiments, the remote unit <NUM> may include at least one of the processor <NUM>, the memory <NUM>, the transmitter <NUM> and the receiver <NUM>, and may not include the input device <NUM> and/or the display <NUM>.

For example, the processor <NUM> may be a microcontroller, a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), an auxiliary processing unit, a field programmable gate array (FPGA), or similar programmable controller.

For example, the memory <NUM> may include a RAM, including dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), and/or static RAM (SRAM). In some embodiments, the memory <NUM> stores data relating to system parameters.

In some embodiments, the input device <NUM> may be integrated with the display <NUM>, for example, as a touch screen or similar touch-sensitive display. In some embodiments, the input device <NUM> includes a touch screen such that text may be input using a virtual keyboard displayed on the touch screen and/or by handwriting on the touch screen.

As another, non-limiting example, the display <NUM> may include a wearable display such as a smart watch, smart glasses, a heads-up display, or the like.

For example, the input device <NUM> and display <NUM> may form a touch screen or similar touch-sensitive display.

The transmitter <NUM> is used to provide UL communication signals to the base unit <NUM> and the receiver <NUM> is used to receive DL communication signals from the base unit <NUM>.

<FIG> depicts one embodiment of another apparatus <NUM> that may be used for power control. The apparatus <NUM> includes one embodiment of the base unit <NUM>. Furthermore, the base unit <NUM> may include at least one of a processor <NUM>, a memory <NUM>, an input device <NUM>, a display <NUM>, a transmitter <NUM> and a receiver <NUM>. As may be appreciated, the processor <NUM>, the memory <NUM>, the input device <NUM>, the display <NUM>, the transmitter <NUM>, and the receiver <NUM> may be substantially similar to the processor <NUM>, the memory <NUM>, the input device <NUM>, the display <NUM>, the transmitter <NUM>, and the receiver <NUM> of the remote unit <NUM>, respectively.

Although only one transmitter <NUM> and one receiver <NUM> are illustrated, the base unit <NUM> may have any suitable number of transmitters <NUM> and receivers <NUM>.

<FIG> is a schematic diagram illustrating a principle of power control according to the first embodiment. <FIG> shows that the parent IAB node <NUM> indicates power value(s) to the child IAB node <NUM>. <FIG> also shows that the child IAB node <NUM> reports power value(s) to the parent IAB node <NUM>.

If the downlink power level of a DL beam from the parent IAB node <NUM> to the child IAB node <NUM> is larger than the maximum power level of the power range of the uplink signal of a UL beam from the UE to the child IAB node <NUM>, the child IAB node <NUM> can only configure the uplink power level to its maximum power level, which is still lower than the downlink power level. The difference of the maximum uplink power level from the downlink power level may be called as "power offset".

The power offset may be different from the above-identified power gap. For example, suppose that the range of downlink power level using DL beam <NUM> is from -140dBm to - 44dBm while the range of uplink power level using UL beam i is from -202dBm to -60dBm, the power gap refers to the difference between the maximum downlink power level (-44dBm) and the maximum uplink power level (-60dBm). On the other hand, the power offset is the power level that the child IAB node <NUM> expects to reduce from the downlink power level of the DL beam. For example, if the downlink power level of a beam (such as the DL beam <NUM> shown in <FIG>) is -50dBm, and the child IAB node <NUM> expects to configure the uplink power level using UL beam i to be -80dBm, the child IAB node <NUM> therefore expects that the downlink power level of the beam (the DL beam <NUM>) to be reduced by 30dBm (-50dBm - (-80dBm)). In this condition, the child IAB node <NUM> may reports to the parent IAB node <NUM> that the power level of the beam (the DL beam <NUM>) is expected to reduce a power offset of 30dBm.

In the above example, the child IAB node <NUM> expects to configure the uplink power level to be a power level (-80dBm) lower than its maximum power level (-60dBm). This is in consideration of other factors such as UE power saving, or reducing interference produced by UE's uplink transmission to other possible receivers.

In this condition, the child IAB node <NUM> reports a power offset of 30dBm for the downlink beam (DL beam <NUM> shown in <FIG>). The power offset is reported by the child IAB node <NUM> to the parent IAB node <NUM> on a per-beam basis. Different beams may have different power levels, which may be resulted from different path losses for different beams. For example, with reference to <FIG>, suppose the power level of DL beam N at the child IAB node <NUM> is - 48dBm, the power offset for the DL beam N to be reported by the child IAB node <NUM> would be 32dBm (-48dBm - (-80dBm)). And if the received power level of DL beam <NUM> at child IAB node <NUM> is -30dBm, then the power offset for the DL beam <NUM> to be reported by the child IAB node <NUM> would be 50dBm (-30dBm - (-80dBm)).

All of the above-described power levels refer to the power levels measured at the child IAB node <NUM>. The power level would experience a path loss when it is transmitted to the child IAB node <NUM>. For example, taking into consideration of an average path loss of 85dBm, the uplink received power level range of -202dBm to -60dBm at the child IAB node <NUM> would correspond to -117dBm (-202dBm+85dBm) to 25dBm (-60dBm+85dBm) at the transmitter side (at the UE). The downlink received power level range of -140dBm to -44dBm at the child IAB node <NUM> would correspond to -55dBm (-140dBm+85dBm) to 41dBm (-44dBm+85dBm) at the transmitter side (at the parent IAB node).

When the parent IAB node <NUM> receives an expected power offset for a specific beam from the child IAB node <NUM>, the parent IAB node <NUM> may indicate to the child IAB node <NUM> the new power level for any specific beam. The new power level for the specific beam may be calculated based on the received power offset. For example, suppose that the previous received power level of the specific beam (DL beam <NUM>) is -50dBm and that the received expected power offset for the specific beam (DL beam <NUM>) is 30dBm (that is the power level to be reduced), the parent IAB node <NUM> may configure the new power level for the specific beam (DL beam <NUM>) to -80dBm (-50dBm-30dBm) and indicate the new power level for the specific beam to the child IAB node <NUM>. Since a beam corresponds to a spatial domain filter, the new power level is also associated with the spatial domain filter. The parent IAB node <NUM> can also indicate to the child node <NUM> that the power offset will be reduced by 30dBm. Alternatively, the parent IAB node <NUM> may choose to indicate another new power level for the specific beam to the child IAB node <NUM>, instead of only being based on the received power offset. For example, the indicated received power level is -70dBm or the power offset indicated is 20dBm. The reason for a different power offset from the reported power offset is that the parent IAB node may serve multiple UEs or child IAB nodes. For efficient multiplexing of the multiple UEs or child IAB nodes, the downlink transmission power should consider all the other multiplexed UEs or child IAB nodes.

As the parent IAB node <NUM> may indicate the new power level for the specific beam (i.e. specific spatial domain filter) to the child IAB node <NUM> without considering the reported power offset from the child IAB node <NUM>, the report of the power offset from the child IAB node <NUM> is independent from the indication of new power level by the parent IAB node <NUM>. In the condition that the parent IAB node <NUM> indicates the new power level to the child IAB node <NUM> without consideration of the report of the power offset from the child IAB node <NUM>, it is referred to as an open loop DL power control. On the other hand, in the condition that the parent IAB node <NUM> considers the report of the power offset when it indicates the new power level to the child IAB node <NUM>, it is referred to as a close loop DL power control. The report of the expected power offset by the child IAB node <NUM> may be implemented independently from the indication of the new power level.

<FIG> illustrates the schematic diagram of the method performed in the parent IAB node <NUM> and in the child IAB node <NUM> according to the second embodiment, in which the child IAB node <NUM> reports the power value to the parent IAB node <NUM>.

In step <NUM>, the parent IAB node <NUM> transmits a set of reference signal (RS) resources to the child IAB node <NUM>. The RS resource may be Channel-state information reference signal (CSI-RS) resource and/or synchronization signal block (SSB) resource. In step <NUM>, the child IAB node <NUM> receives the set of reference signal (RS) resources. Each RS resource is associated with a beam, and therefore associated with a spatial domain filter. Different RS resources may be transmitted using different beams (different spatial domain filters). Incidentally, different RS resources may also be transmitted using the same beam (the same spatial domain filter). For example, a CSI-RS resource and a SSB resource may be transmitted using the same beam (the same spatial domain filter). As a whole, each RS resource is transmitted from the parent IAB node <NUM> to the child IAB node <NUM> using a specific beam (a specific spatial domain filter).

In step <NUM>, the parent IAB node <NUM> transmits a reporting quantity configuration to the child IAB node <NUM>. The reporting quantity configuration may include power levels for one or multiple RS resources in the set of RS resources. Since each RS resource is associated with a beam (spatial domain filter), the reporting quantity configuration actually includes power levels for the beam(s) (spatial domain filter(s)) associated with the one or multiple RS resources. Alternatively, the reporting quantity configuration may include both power levels and the resource indices of the power levels, wherein the resource indices are also associated with corresponding beams (spatial domain filters). The power levels may be the absolute power levels transmitted at the parent IAB node <NUM>, or the absolute power levels received at the child IAB node <NUM>, or the power offset compared to the previous power levels. The difference between the received power level and the transmitted power level is the path loss.

In step <NUM>, the child IAB node <NUM> reports power values for one or multiples beams (spatial domain filters) to the parent IAB node <NUM>. And in step <NUM>, the parent IAB node <NUM> receives the power values for the one or multiple beams (spatial domain filters).

In step <NUM>, the child IAB node <NUM> receives a set of RS resources (which represent a set of beams used for transmitting), which are used to determine the power offset for each corresponding beam. In step <NUM>, the child IAB node <NUM> receives the reporting quantity configurations, which can be the power value for one or multiple beams of the set of RS resources in step <NUM>. The power value can be the power levels transmitted at the parent IAB node <NUM> or the power levels received at the child IAB node <NUM>. For example, one RS resource is transmitted using DL beam <NUM> shown in <FIG> and its power level received at the child IAB node <NUM> is -50dBm, and another RS resource is transmitted using DL beam N shown in <FIG> and its power level received at the child IAB node <NUM> is -48dBm. Meanwhile, if the uplink power level received at the child IAB node <NUM> is -80dBm, then the power offset for DL beam <NUM> is 30dBm, and the power offset for DL beam N is 32dBm. Accordingly, in step <NUM>, the child IAB node <NUM> receives a set of RS resources including two RS resources (one of which is associated with DL beam <NUM> and another of which is associated with DL beam N). In step <NUM>, the child IAB node <NUM> receives the reporting quantity configuration. The reporting quantity configuration can be for all the resources (beams) or for one or multiplex best resources (beams).

In step <NUM>, the child IAB node <NUM> reports power values for the received RS resources. If the reporting quantity configuration is for all the resources (beams), then both power offset 30dBm and 32dBm will be reported simultaneously, wherein 30dBm is for DL beam <NUM>, and 32dBm is for DL beam N. If the reporting quantity configuration is for one best resource (beam), then the reported information may be both 30dBm and DL beam <NUM> to indicate that DL beam <NUM> is the best beam and its corresponding power offset is 30dBm. DL beam <NUM> can be indicated by resource index <NUM>. If the best beam determined by the child IAB node <NUM> is DL beam N, then the reported information will be both 32dBm and DL beam N. DL beam N can be indicated by resource index <NUM>.

There are various factors to be considered for the report.

<FIG> illustrates the schematic diagram of the method performed in the parent IAB node <NUM> and in the child IAB node <NUM> according to the third embodiment.

In step <NUM>, the parent IAB node <NUM> configures a mapping relation between Transmission Configuration Indication (TCI) states and power values and transmits the mapping relation to the child IAB node <NUM>. A TCI state is related to a CSI-RS or SSB resource, and it corresponds to a spatial beam and also corresponds to a spatial domain filter. In step <NUM>, the child IAB node <NUM> receives the mapping relation.

In one embodiment, a TCI state set and a power value set are respectively configured. A TCI state is mapped to a power value with the same index. Each TCI state is associated with a beam and therefore associated with a spatial domain filter. Therefore, a mapping relation between the TCI state and the power value creates a look-up table for the power value of each beam (spatial domain filter).

For example, the mapping relation may be as follows:.

The power value may be a power offset that indicates that the power level to be reduced, or an absolute power level used for the corresponding beam. The absolute power level may be the power level transmitted at the parent IAB node <NUM> or the power level received at the child IAB node <NUM>.

In step <NUM>, the parent IAB node <NUM> indicates a TCI state to the child IAB node <NUM>. In step <NUM>, the child IAB node <NUM> receives the indicated TCI state.

The child IAB node <NUM> receives the indicated TCI state, and checks the mapping relation between the TCI state and the power value, and learns the power value for the beam (spatial domain filter) corresponding to the indicated TCI state.

In step <NUM>, the child IAB node <NUM> determines the power level for thedownlink signal received from the parent node <NUM> with the indicated or determined TCI state. Accordingly, based on the power level for the downlink signal, the child IAB node <NUM> can configure the power level for the uplink signal to a level that is approximately the same as the power level of the downlink signal.

There are a variety of options to configure the mapping relation between TCI states and power values and indicate the TCI state.

In the condition that the mapping is configured by RRC signaling, there are several ways to indicate the TCI state. The TCI state may be indicated differently for different channels such as Physical Downlink Shared Channel (PDSCH), Physical Downlink Control Channel (PDCCH) and CSI-RS for CSI measurement.

(<NUM>-<NUM>) When DCI (Downlink Control Information) 1_1 is used for scheduling PDSCH, the TCI state contained in the DCI 1_1 can be used as the indicated TCI state.

(<NUM>-<NUM>) When DCI 1_0 is used for scheduling PDSCH, the default TCI state for the DCI 1_0 can be used as the indicated TCI state.

(<NUM>-<NUM>) For PDCCH, a TCI state that is configured by RRC and MAC CE can be used. In this case, RRC signaling configures a set of TCI states, and MAC CE signaling selects one TCI state from the set of TCI states as the indicated TCI state.

(<NUM>-<NUM>) For periodic CSI-RS used for CSI measurement, a TCI state in the CSI-RS resource configuration can be used as the indicated TCI state.

(<NUM>) Option <NUM>: the mapping relation between TCI state and power value is configured by MAC CE signaling.

Each MAC CE signaling has a logical channel identification (LCID). A new LCID is introduced to indicate that a specific MAC CE signaling with the new LCID is used for configuring the mapping relation between TCI states and power values.

In the condition that the mapping is configured by MAC CE signaling (i.e. Option <NUM>), all of the above-described (<NUM>-<NUM>)-(<NUM>-<NUM>) can be used to indicate the TCI state.

(<NUM>) Option <NUM>: DCI 2_0 or DCI 2_2 or DCI 2_3 is used to indicate the power value of each TCI state. In this case, a first RRC signaling is used to configure a TCI state set, and the format in DCI 2_0 or DCI 2_2 or DCI 2_3 will be: power value <NUM>, power value <NUM>, etc. A second RRC signaling is used to configure the starting position in DCI 2_0 (or DCI 2_2 or DCI 2_3) for each TCI state in the TCI state set. For example, for TCI state <NUM>, if the configured starting position is <NUM> (suppose each power value occupies <NUM> bits, and the power value <NUM> is the first part in DCI 2_0 or DCI 2_2 or DCI 2_3), then it means that the power value for TCI state <NUM> is power value <NUM>; and if the configured starting position for TCI state <NUM> is <NUM>, then the power value for TCI state <NUM> is power value <NUM> in DCI 2_0 or DCI 2_2 or DCI 2_3.

In the condition that the mapping is configured by RRC signaling and DCI 2_0 (or DCI 2_2 or DCI 2_3) (i.e. Option <NUM>), all of the above-described (<NUM>-<NUM>)-(<NUM>-<NUM>) can be used to indicate the TCI state.

In the condition that the mapping is configured using DCI 2_0 or DCI 2_2 or DCI 2_3, the applicable range of the power value in time domain is from the reception of the DCI 2_0 or DCI 2_2 or DCI 2_3 to the reception of a new DCI 2_0 or DCI 2_2 or DCI 2_3.

(<NUM>) Option <NUM>: When DCI 1_1 is used to schedule PDSCH, both a TCI state and a power value indication are contained in the DCI 1_1. It means that the corresponding PDSCH is transmitted with the indicated TCI state, and the received power level of the PDCSH at the child IAB node can be determined based on the indicated power value. In one embodiment, the power value indication can be a power offset to reduce the power level, or an absolute transmission power level at the parent IAB node side or a reception power level at the child IAB node side. In another embodiment, multiple power values can be configured by RRC signaling, and DCI 1_1 selects one of them. The multiple power values can be multiple power offsets, multiple transmission power levels or multiple reception power levels. For example, RRC signaling configures <NUM> possible power offsets: 0dBm, 10dBm, 20dBm, and 30dBm. If the power value indication in DCI 1_1 is <NUM>, it means that the power offset is 0dBm, and if the power value indication in DCI 1_1 is <NUM>, then the power offset is 20dBm. The RRC signaling also configures the number of bits used for a power value indication. For example, if only <NUM> power offsets are configured, <NUM> bits are enough for indicate four values.

In the above-described Options <NUM>-<NUM>, in case of SDM or FDM between the backhaul link and the access link, if the indication of the TCI state from the parent IAB node <NUM> is made by DCI 1_1, the corresponding scheduled PDSCH will have <NUM> or <NUM> slot delay from DCI 1_1. On the other hand, when the child IAB node <NUM> schedules PUSCH by PDCCH, the delay between PDCCH and PUSCH is about <NUM> slots. That is to say, if the PDSCH and the PUSCH is at the same time domain resource, then the PDCCH scheduling PUSCH should be before the PDCCH scheduling PDSCH. So the control information in PDCCH scheduling PUSCH can't be determined based on the PDCCH scheduling PDSCH. In this condition, the child IAB node <NUM> determines the power control for the uplink signal from the access UE based on a default TCI state. The default TCI state may be the TCI state with index <NUM> in a predetermined TCI state set. In this case, the power value corresponding to the TCI state with index <NUM> in the predetermined TCI state set is assumed as the downlink reception power at the child IAB node from the parent IAB node, and the uplink reception power at the child IAB node from the access UE can be determined approximately same as the downlink reception power. Alternatively, the child IAB node <NUM> may determine the power control for the uplink signal from the access UE based on a default TCI state set. In particular, the smallest or the largest value among power values for all the TCI states in the default TCI state set may be assumed as the downlink reception power at the child IAB node from the parent IAB node. The TCI states contained in both the predetermined TCI state set and the default TCI state set may be selected from all or part of the TCI state values configured by RRC signaling or all or part of the TCI states indicated in MAC CE signaling or DCI 2_0 (or DCI 2_2 or DCI 2_3).

In the above-described Options <NUM>-<NUM>, in case of FDM between the backhaul link and the access link, different frequency domain resources are used for the transmission from the parent IAB node to the child IAB node and the transmission from the UE to the child IAB node. If the PDCCH scheduling PUSCH is before the PDCCH scheduling PDSCH, the frequency domain resource allocation information in PDCCH scheduling PUSCH can't be determined based on the frequency domain resource allocation information in PDCCH scheduling PDSCH. In this condition, the frequency domain resource allocation in PDCCH scheduling PUSCH can be determined based on a semi-static configuration of the PDSCH. For example, a BWP (bandwidth part) is always configured for the PDSCH transmission from parent IAB node to child IAB node, and a set of frequency domain resources indicated in the BWP configuration may be used by the PDSCH transmission. So the PDCCH scheduling PUSCH can determine the frequency domain resource allocation by avoiding all the frequency domain resources corresponding to the bandwidth part.

The purpose for power or TCI indication or BWP indication in the parent link is for SDM or FDM multiplexing between the parent backhaul link and the child backhaul/access link. A relationship between the power or TCI or BWP (set) and slot format indication can be established by RRC signaling or predefined. For example, two power values can be configured by RRC signaling as: power value <NUM>, power value <NUM>. And power value <NUM> is assumed when TDM is adopted, and power value <NUM> is assumed when FDM or SDM is adopted. If the slot format indicates that FDM or SDM between parent backhaul link and access link is enabled, then the received power level is determined to be power value <NUM> implicitly. So in this case, there is no additional signaling for power value indication. Similar implicit signaling can also be applied to TCI indication or BWP indication.

In another embodiment, when the subcarrier spacings (SCSs) for parent backhaul link and for access link are different, a common resource grid (SCS) should be determined to obtain a suitable resource for FDM between two links. For example, if the backhaul link SCS is <NUM>, and the SCS for access link is <NUM>, then the common grid can be based on l <NUM>. In this case, a subcarrier with <NUM> corresponds to <NUM> subcarriers. If the subcarrier index for the backhaul link with <NUM> ranges from <NUM> to <NUM>, when it transfers to <NUM>, the index will be from <NUM> to <NUM>, with index <NUM> divided into indices <NUM>,<NUM>,<NUM>,<NUM>, and index <NUM> divided into indices <NUM>,<NUM>,<NUM>,<NUM>, etc..

The power value for PDSCH has been described above. The scheduled PDSCH time and frequency range also applies to PTRS (phase tracking reference signal) and DMRS (demodulation signal) within the scheduled PDSCH time and frequency range.

Claim 1:
A method performed by a child integrated access backhaul, IAB, node (<NUM>), the method comprising:
receiving (<NUM>) a first signalling indicating one or multiple power values for a downlink reception from a parent IAB node (<NUM>), each power value being associated with a spatial domain filter, wherein the power values associated with one or multiple spatial domain filters are configured by radio resource control, RRC, signalling or medium access control, MAC, control element, CE, signalling, or any combination thereof; and
determining (<NUM>) a power value for the downlink reception from the parent IAB node (<NUM>), wherein the power value is a power offset that indicates a power level to be reduced, or an absolute transmitting power level, or an absolute receiving power level, and wherein the power value for physical downlink shared channel, PDSCH, scheduled by a downlink control information, DCI, is determined by a transmission configuration information, TCI, state in the DCI or a default TCI state or a default TCI state set, and the TCI state is used to determine the spatial domain filter.