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).

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

A half duplex restriction at a node means that a node cannot perform transmission and reception simultaneously. Since there a half duplex restriction at the IAB node, resource partitioning between an access link and a backhaul link is necessary. In this case, some of the time domain resources are allocated only for supporting the backhaul link and others are allocated only for supporting the access link. This configuration is referred to as TDM-based resource partitioning between the access link and the backhaul link. In the IAB system shown in <FIG>, a parent node determines TDM resource partitioning between the backhaul link and the access link. The parent node may allocate some resources for DL and UL transmissions for a backhaul link, and reserve certain other resources for its child node, i.e., the resources for the access link between the child node and its served UE.

<FIG> shows an example of a slot format indicated by the parent node for the backhaul link and a slot format indicated by the child node for the access link based on TDM scheme. As shown in <FIG>, a single slot has <NUM> symbols (symbol <NUM> to symbol <NUM>). A slot shown in the upper part of <FIG>, identifies a parent node allocation where first four symbols (each indicated with letter "D") are allocated for the DL transmission on the backhaul link, and the last two symbols (each indicated with letter "U") are allocated for the UL transmission on the backhaul link. In addition, middle eight symbols (each indicated with a letter "F") are reserved for the child node to use for the access link between the child node and its served UE. As shown in the lower part of <FIG>, as the first four symbols and the last two symbols are allocated by the parent node for use for the backhaul link, the child node indicates these six symbols as reserved (each indicated with letter "F"), i.e., not used to support communication over the access link. Among the middle eight symbols, the child node allocates the first four symbols for the DL transmission for the access link (each indicated as an "D"), allocates the last two symbols for the UL transmission for the access link (each indicated as an "U"). In addition, the middle two symbols won't be used by the child node for the access link, so they are also indicated as reserved. In in a situation where a served UE also function as a second child node serving a second UE, the reserved symbols (including <NUM> symbols in the beginning, <NUM> symbols in the middle and <NUM> symbols in the end) may be allocated by this served UE (i.e., the second child node) to be used for the link between itself and the second UE.

However, this mechanism may cause some problems for transmissions via data channels (i.e. PDSCH and PUSCH) and control channels (PDCCH and PUCCH).

For example, since transmission of the DL resources (on PDSCH) and UL resources (on PUSCH) is fragmented, each fragmented resource has to be scheduled by an individual PDCCH. For example, when referring to <FIG>, a PDCCH (DL grant) is used to schedule symbols <NUM>-<NUM> of slot <NUM>, and another PDCCH (DL grant) is used to schedule symbols <NUM>-<NUM> of slot <NUM>. Hence, two PDCCHs are necessary to schedule transmission of DL symbols in slot <NUM> and slot <NUM>, with the total scheduled DL symbols in both slots being <NUM> symbols, which leads to large control signaling overhead. Similarly, the UE has to be configured with too many PDCCH monitoring occasions. This would lead to high blind detection effort, high power consumption and large control channel overhead.

Another problem may be caused by the mismatch between the preconfigured control channel (i.e., PDCCH and PUCCH) resource and the slot format indicated by DCI format 2_0. In NR, the time domain resource for PDCCH and PUCCH is semi-statically configured by RRC signaling. On the other hand, the slot format information is carried by DCI format 2_0. For example, as shown in the upper sequence of slots in <FIG>, the first two symbols (symbol <NUM> and symbol <NUM>) of slot <NUM> are preconfigured by RRC signaling as the resources for the PDCCH transmission between the child node and the UE. On the other hand, the slot format indicated in the DCI format 2_0 transmitted from the child node may reserve the resources including the first two symbols of the slot <NUM> for use over the backhaul link. That is to say, the first two symbols of the slot <NUM> cannot be used for the access link between a child node and the UE. In this condition, the PDCCH transmission between the child node and the UE preconfigured by the RRC signaling in the first two symbols of the slot <NUM> has to be abandoned.

<CIT> describes a mechanism for wireless device-to-device (D2D) communications that includes deriving a plurality of virtual subframes from an allocation of radio resources, the virtual subframes comprising a virtual special subframe and a virtual forward link subframe wherein the virtual forward link subframe comprises a first forward link portion and the virtual special subframe comprises one or more of: a second forward link portion, and a reverse link portion.

Methods and apparatuses for time domain resource allocation are disclosed. Claims <NUM> and <NUM> define respective methods, claim <NUM> defines a remote unit and claim <NUM> defines a base unit. In the following, any method and/or apparatus referred to as embodiments but nevertheless do not fall within the scope of the appended claims are to be understood as examples helpful in understanding the invention.

In one embodiment, a method comprises: receiving a first slot format indicating a first time domain resource; receiving an indicator indicating a second time domain resource allocated for data or control channel transmission; mapping the second time domain resource to a third time domain resource, wherein the third time domain resource is a subset of the first time domain resource; and receiving the data or control channel transmission from the third time domain resource. Although the method may imply that the first slot format is received before the indicator is received, the indicator may be received before the first slot format is received.

In some embodiment, the method further comprises determining a mapping boundary for mapping. In one embodiment, the mapping boundary includes a starting position and an ending position, and the starting position and the ending position are aligned with a physical slot boundary, respectively. In another embodiment, the mapping boundary includes a starting position and an ending position, and the starting position and the ending position are determined based on the monitoring occasion and periodicity for receiving the first slot format. In yet another embodiment, the mapping boundary includes a starting position and an ending position, and the starting position and the ending position are determined based on starting and ending of consecutive available time domain resources.

In some embodiment, the indicator indicating the second time domain resource for the data channel transmission is a second slot format including consecutive DL symbols and UL symbols without reserved symbols intervened. In one embodiment, the DL symbols and the UL symbols are interlaced. In another embodiment, the DL symbols the UL symbols are continuous, respectively. In yet another embodiment, in the first slot format, DL symbols and UL symbols are non-consecutive, respectively, and the mapping comprises mapping the consecutive symbols in the second slot format to the non-consecutive symbols in the first slot format. Optionally, the first slot format further includes reserved symbols.

In some embodiment, the first slot format includes unavailable symbols and available symbols for control channel transmission, and the mapping comprises mapping the unavailable symbols to the available symbols circularly.

In some embodiment, a method comprises: transmitting a first slot format indicating a first time domain resource; mapping a third time domain resource for data channel transmission to a second time domain resource, wherein the third time domain resource is a subset of the first time domain resource; transmitting an indicator indicating the second time domain resource; and transmitting the data channel on the third time domain resource.

In some embodiment, a method comprises: transmitting a first slot format indicating a first time domain resource; transmitting an indicator indicating a second time domain resource allocated for control channel transmission; mapping the second time domain resource to a third time domain resource, wherein the third time domain resource is a subset of the first time domain resource; and transmitting the control channel transmission on the third time domain resource.

In some embodiment, a remote unit comprises: a receiver that receives a first slot format indicating a first time domain resource, and an indicator indicating a second time domain resource allocated for data or control channel transmission; and a processor that maps the second time domain resource to a third time domain resource, wherein the third time domain resource is a subset of the first time domain resource, wherein the receiver receives the data or control channel transmission from the third time domain resource.

In some embodiment, a base unit comprises: a transmitter that transmits a first slot format indicating a first time domain resource; and a processor that maps a third time domain resource for data channel transmission to a second time domain resource, wherein the third time domain resource is a subset of the first time domain resource; wherein the transmitter transmits an indicator indicating the second time domain resource, and transmits the data channel on the third time domain resource.

In some embodiment, a base unit comprises: a transmitter that transmits a first slot format indicating a first time domain resource, and an indicator indicating a second time domain resource allocated for control channel transmission; and a processor that maps the second time domain resource to a third time domain resource, wherein the third time domain resource is a subset of the first time domain resource, wherein the transmitter transmits the control channel transmission on the third time domain resource.

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 time domain resource allocation. In one embodiment, the wireless communication system <NUM> includes parent nodes <NUM>, child nodes <NUM> and UEs <NUM>. Even though only one parent node <NUM>, one child node <NUM> and one UE <NUM> are depicted in <FIG>, one skilled in the art will recognize that any number of parent nodes <NUM>, child nodes <NUM> and UEs <NUM> may be included in the wireless communication system <NUM>.

In the backhaul link between the parent node <NUM> and the child node <NUM>, the parent node functions as a base unit <NUM> while the child node functions as a remote unit <NUM>. In the access link between the child node <NUM> and the UE <NUM>, the child 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 time domain resource allocation. 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 time domain resource allocation. 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> shows an embodiment of aggregating fragmented resources. The physical index <NUM> sequence of slots depicted in <FIG> shows a slot format partitioning between a child node and a UE for DL transmission and UL reception as indicated by DCI format 2_0. For ease of discussion, <FIG> shows a slot format partitioning associated with only two slots (slot <NUM> and slot <NUM>), wherein each slot includes <NUM> symbols (from symbol <NUM> to symbol <NUM>). In <FIG>, a starting position of the slot format is symbol <NUM> of slot <NUM>, and the ending position of the slot format is symbol <NUM> of slot <NUM>.

The slot format associated with the physical index <NUM> sequence of slots <NUM> and <NUM> of <FIG> is FFFDDDDFFFFFUU+FFFFDDDDDDFFFU, in which "F" represents a reserved symbol, i.e., symbols non-used for the access link between a child node and a UE (these symbols might be scheduled by a parent node to be used for the backhaul link between the parent node and the child node); "D" represents symbols for DL (downlink) transmission (e.g. on PDSCH) from the child node to the UE; and "U" represents symbols for UL (uplink) transmission (e.g. on PUSCH) from the UE to the child node. It thus can be seen that symbols <NUM>-<NUM> and <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> and <NUM>-<NUM> of slot <NUM> are reserved symbols; symbols <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM> are symbols allocated for downlink transmission; and symbols <NUM>-<NUM> of slot <NUM> and symbol <NUM> of slot <NUM> are symbols allocated for uplink transmission.

It can be seen that symbols for downlink transmission, i.e., symbols <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM>, are fragmented. Further, symbols for the uplink transmission, i.e., symbols <NUM>-<NUM> of slot <NUM> and symbol <NUM> of slot <NUM>, are also fragmented.

Such fragmentation requires that each fragmented resource has to be scheduled by an individual PDCCH from the child node to the UE. Therefore, resources used to transmit information on symbols <NUM>-<NUM> of slot <NUM> and on symbols <NUM>-<NUM> of slot <NUM> have to be scheduled by the child node separately. This results in UE monitoring each of the scheduled resources on PDCCH from the child node, which is extremely inefficient in the condition when there are many fragmented resources to be used.

To overcome this inefficiency, fragmented resources may be mapped into a virtual format representing continuous time domain resources. <FIG> shows an embodiment of aggregating fragmented resources by mapping the fragmented resources into continuous resources.

First, the mapping boundary of the fragmented resources has to be determined. The mapping boundary may include a starting position and an ending position. In <FIG>, the starting position is associated with symbol <NUM> of slot <NUM>, and the ending position is associated with symbol <NUM> of slot <NUM>.

The mapping boundary is not limited to that shown in <FIG>. The mapping boundary, i.e., the starting position and the ending position, may be determined in different ways. In a first option (Option <NUM>), the starting position and the ending position may be predetermined as being aligned with the physical slot boundary. The length from the starting position to the ending position may also be predetermined. For example, if the length is <NUM> slots, symbol <NUM> in slot <NUM>, symbol <NUM> in slot <NUM>, symbol <NUM> in slot <NUM>, etc., may correspond to starting positions, respectively. Similarly, symbol <NUM> in slot <NUM>, symbol <NUM> in slot <NUM>, symbol <NUM> in slot <NUM>, etc., may correspond to ending positions, respectively.

Alternatively, in a second option (Option <NUM>), the starting position and the ending position may depend on monitoring occasion and periodicity of the DCI format 2_0.

In this second option, the slot boundary where DCI format 2_0 is detected may be determined as the starting position, and the ending position would be the starting position plus the periodicity for monitoring DCI format 2_0. For example, suppose that the DCI monitoring periodicity is <NUM> slots, slot offset is <NUM>, and symbol position is <NUM>. The DCI monitoring periodicity, slot offset and the symbol position indicate where the UE should start monitoring the DCI format 2_0 message. With periodicity being equal to <NUM> slots, a slot offset being set to <NUM> slot and a symbol position being set to <NUM> symbols, UE would expect to receive the first symbol of the DCI format 2_0 message on symbol <NUM> of slot <NUM>, symbol <NUM> of slot <NUM>, symbol <NUM> of slot <NUM>, etc..

In this condition, the starting position and the ending position of the mapping may be determined on the basis of the monitoring periodicity, the slot offset and the symbol position. For example, the starting position may be determined as symbol <NUM> of slot <NUM>, symbol <NUM> of slot <NUM>,. , etc; and the ending position may be determined as symbol <NUM> of slot <NUM>, symbol <NUM> of slot <NUM>,. , etc. Alternatively, the determination may only be made on the basis of the monitoring periodicity and the slot offset (i.e. the symbol position is not considered for simplicity). For example, in the above example, the starting position may be determined as symbol <NUM> of slot <NUM> (i.e. the first symbol of the slot where the DCI format 2_0 is monitored) and the ending position would be symbol <NUM> of slot <NUM>.

A virtual index <NUM> sequence of slots depicted in the middle of <FIG> shows a first version of the virtual format representing continuous time domain resources. This first version of the virtual format is depicted by a continuous set of symbols: DDDDUUDDDDDDU, which is obtained by excluding reserved resources and concatenating symbols used for downlink and uplink transmission. The slot format indicated in DCI format 2_0 may be referred to as a physical format. In particular, symbols <NUM>-<NUM> of slot <NUM> of the physical format are mapped to symbols <NUM>-<NUM> of slot <NUM> of the virtual format; symbols <NUM>-<NUM> of slot <NUM> of the physical format are mapped to symbols <NUM>-<NUM> of slot <NUM> of the virtual format; symbols <NUM>-<NUM> of slot <NUM> of the physical format are mapped to symbols <NUM>-<NUM> of slot <NUM> of the virtual format; and symbol <NUM> of slot <NUM> of the physical format is mapped to symbol <NUM> of slot <NUM> of the virtual format. Therefore, fragmented symbols are aggregated into continuous set of symbols.

Finally, a virtual index <NUM> sequence of slots depicted in the lower part of <FIG> shows another virtual format representing continuous time domain resources. This second version of the virtual format is identified by a continuous set of symbols: DDDDDDDDDDUUU, which is also obtained by excluding the reserved resources and concatenating symbols used for downlink and uplink transmission. This second version of the virtual format differs from the first version in that all of symbols used for downlink transmission are grouped first prior to being concatenated with the uplink transmission symbols. In particular, symbols <NUM>-<NUM> of slot <NUM> of the physical format are mapped to symbols <NUM>-<NUM> of slot <NUM> of the second virtual format; symbols <NUM>-<NUM> of slot <NUM> of the physical format are mapped to symbols <NUM>-<NUM> of slot <NUM> of the second virtual format; symbols <NUM>-<NUM> of slot <NUM> of the physical format are mapped to symbols <NUM>-<NUM> of slot <NUM> of the second virtual format; and symbol <NUM> of slot <NUM> of the physical format is mapped to symbol <NUM> of slot <NUM> of the second virtual format.

<FIG> describes a reverse mapping from the virtual format to the physical slot format indicated in DCI format 2_0.

Suppose that the child node schedules six symbols for downlink transmission, e.g. symbols <NUM>-<NUM> identified in slot <NUM> of a virtual format time domain resource, as shown in the Scheduled PDSCH sequence of slots in <FIG>. For UE to successfully receive these virtual symbols, it has to know which physical time domain resource(s) were used to transmit them, i.e. what physical slot format was used.

To correctly identify physical time domain resource used, UE makes reverse mapping with respect to the mapping shown in <FIG>. For example, taking the second version of the virtual format mapping example, described by the physical index <NUM> and the virtual index <NUM> slot sequences of <FIG>, the UE must now reverse the mapping of symbols <NUM>-<NUM> of slot <NUM> of the physical format to symbols <NUM>-<NUM> of slot <NUM> of the virtual format; of symbols <NUM>-<NUM> of slot <NUM> of the physical format to symbols <NUM>-<NUM> of slot <NUM> of the virtual format; of symbols <NUM>-<NUM> of slot <NUM> of the physical format to symbols <NUM>-<NUM> of slot <NUM> of the virtual format; and of symbol <NUM> of slot <NUM> of the physical format to symbol <NUM> of slot <NUM> of the virtual format.

The virtual index <NUM> and physical index <NUM> slot sequences of <FIG> illustrate such reverse mapping, between the virtual format and a physical format, respectively, where symbols <NUM>-<NUM> of a virtual format slot <NUM> associated with virtual index <NUM> sequence of slots are mapped to symbols <NUM>-<NUM> of the physical format slot <NUM>; symbols <NUM>-<NUM> of the virtual format slot <NUM> are mapped to symbols <NUM>-<NUM> of the physical format slot <NUM>; symbols <NUM>-<NUM> of the virtual format slot <NUM> are mapped to symbols <NUM>-<NUM> of the physical format slot <NUM> ; and symbol <NUM> of the virtual format slot <NUM> is mapped to symbol <NUM> of the physical format slot <NUM>.

According to such reverse mapping, a UE or a child node, when it acts as the UE, will be able to determine that the scheduled symbols <NUM>-<NUM> of the virtual format slot <NUM> will actually be transmitted on the downlink as symbols <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM> of the physical format.

In <FIG>, the child node is indicated as a base unit, and the UE is indicated as a remote unit. <FIG> illustrates the schematic diagram of the methods performed in the base unit and in the remote unit according to the first embodiment.

In step <NUM>, the base unit transmits DCI format 2_0 to the remote unit indicating a physical slot format associated with transmitted symbols. For example, the physical slot format indicated in the DCI format 2_0 may be a physical format shown in the physical index <NUM> slot sequence of <FIG>. In step <NUM>, the remote unit receives the DCI format 2_0.

The periodicity of transmitting the DCI format 2_0 is predetermined. Each time the DCI format 2_0 is transmitted, the physical format of symbols indicated in the DCI format 2_0 may be changed. Symbols allocated for downlink transmission of the access link, symbols allocated for uplink transmission of the access link and reserved symbols may be changed. Therefore, each time the remote unit receives a new DCI format 2_0, the physical format indicated may differ. As a consequence, mapping between a virtual format and a physical format may accordingly be changed.

In step <NUM>, the base unit maps the symbols of the physical format to the symbols of the virtual format. In particular, according to the mapping boundary described in Option <NUM> and the first version of the virtual format mapping between the physical index <NUM> slot sequence of <FIG> and the Virtual index <NUM> slot sequence, or according to the mapping boundary of Option <NUM> and the second version of the virtual format mapping between the physical index <NUM> slot sequence of <FIG> and the Virtual index <NUM>, the base unit performs physical to virtual time domain resource mapping. For example, in the condition that downlink resources are to be transmitted and the second version of the virtual format is adopted (and with the mapping boundary of the Option <NUM>), symbols transmitted on physical downlink time domain resources shown in the Physical index <NUM> slot sequence of <FIG> would be mapped to the symbols for the virtual time domain resource shown in the Scheduled PDSCH slot sequence of <FIG>.

In step <NUM>, the base unit transmits a DL grant to initiate a PDSCH transmission. Alternatively, if a UL grant is transmitted, a PUSCH transmission is initiated. The DL grant includes a schedule of symbols according to a virtual format. In step <NUM>, the remote unit receives the DL grant including the schedule. The DL grant provides the remote unit with necessary information to prepare for the DL transmission.

Upon receiving DL grant including a schedule, remote unit, in step <NUM>, calculates the actual symbols for receiving the downlink resources by reverse-mapping the symbols indentified in the virtual format received in the scheduling information to the symbols of the physical format. For example, as shown in <FIG>, the UE receives a schedule for PDSCH shown in the scheduled PDSCH of <FIG>, and according to the predetermined reverse mapping rule and the physical format received on step <NUM>, reverse-maps the symbols shown in the scheduled PDSCH of <FIG> to the symbols shown in the physical index <NUM> of <FIG>.

In step <NUM>, the base unit transmits symbols on physical time domain resources (PDSCH), e. g symbols shown in the physical index <NUM> sequence of slots of <FIG>. In step <NUM>, the remote unit receives such symbols of the physical format, e.g. the symbols shown in the physical index <NUM> of <FIG>.

According to the methods described with reference to <FIG>, the remote unit reverse-maps the virtual format to the physical format based on the received DCI format 2_0 for a set of time domain resources. Once a new DCI format 2_0 is received at step <NUM>, the remote unit would update the mapping based on the new DCI format 2_0. Upon receiving the DL grant including the schedule of symbols of the virtual format at step <NUM>, the remote unit automatically calculate the actual symbols (e.g. the physical index <NUM> in <FIG>) for reception based on the newly received DCI format 2_0, which is a subset of the set of time domain resources based on the scheduling information. Therefore, the remote unit always knows the actual symbols expected to be received.

According to the first embodiment, the fragmented resources to be used may be aggregated to be scheduled together with a single PDCCH. Therefore, the overhead for scheduling at the base unit and the detection effort at the remote unit would be greatly reduced.

The first embodiment is described with reference to PDSCH. Similarly, the first embodiment also applies to the PUSCH.

Since the time domain resource configuration of the control channel is semi-statically configured, there might be a mismatch between preconfigured control channel (PDCCH and PUCCH) time domain resource configurations and the slot format indicated by DCI format 2_0, since the DCI format 2_0 changes more frequently than control channel time domain resource configuration.

<FIG> shows an embodiment of circular mapping of unavailable symbols to available symbols. The upper physical index <NUM> slot sequence of <FIG> shows the slot format used between a child node and an UE for DL and UL transmissions as indicated by DCI format 2_0. For ease of discussion, <FIG> shows the slot format that only contains three slots (slot <NUM>, slot <NUM> and slot <NUM>), wherein each slot includes <NUM> symbols (from symbol <NUM> to symbol <NUM>).

The slot format depicted in the physical index <NUM> slot sequence of <FIG> is FFFDDDDFFFFFUU + FFFFDDDDDDFFFU + FFDDDFFUUUUUUU for slots <NUM>-<NUM>, in which "F" represents a reserved symbol, i.e., symbol that are not-used for the access link between the child node and the UE (that might be scheduled by a parent node to be used for the backhaul link between the parent node and the child node); "D" represents a symbol for DL (downlink) transmission (e.g.. PDCCH) from the child node to the UE; and "U" represents symbol for UL (uplink) transmission (e.g., PUCCH) from the UE to the child node. It thus can be seen that symbols <NUM>-<NUM> and <NUM>-<NUM> of slot <NUM>, symbols <NUM>-<NUM> and <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> and <NUM>-<NUM> of slot <NUM> are reserved symbols; symbols <NUM>-<NUM> of slot <NUM>, symbols <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM> are symbols for downlink transmission; and symbols <NUM>-<NUM> of slot <NUM>, symbol <NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM> are symbols for uplink transmission.

It can be seen that the symbols for downlink transmission are only symbols <NUM>-<NUM> of slot <NUM>, symbols <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM>. In other words, the downlink transmission (PDCCH) can be made only in symbols <NUM>-<NUM> of slot <NUM>, symbols <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM>. Since the time domain resource configuration for PDCCH may be semi-statically configured by RRC signaling, for example, the resource for PDCCH (e.g. physical index <NUM> in <FIG>) may be pre-configured by RRC signaling on symbols <NUM>-<NUM> of slot <NUM>, while the slot format transmitted in DCI 2_0, on the other hand, can be changed a lot more frequently. In the condition that the DCI format 2_0 is set (changed) to the slot format shown in the physical index <NUM> slot sequence of <FIG>, symbols <NUM>-<NUM> of slot <NUM> will now belong to a reserved symbols set, i.e., symbols that cannot be used for the access link between the child node and the UE. In this condition, it is impossible to transmit PDCCH in the symbols <NUM>-<NUM> of slot <NUM> for the access link between the child node and the UE.

To solve this mismatch between the preconfigured PDCCH (as well as PUCCH) resources and the slot format indicated by DCI format 2_0, <FIG> shows an embodiment of mapping of the unavailable symbols for transmission to available symbols performed at both the base unit and the remote unit side.

First, to begin the mapping process, mapping duration (or boundary) is determined. The mapping duration is a duration when the mapping between the physical resource and virtual resource is performed. It always has a starting boundary and an ending boundary. Same mapping principle or options will be adopted in the mapping duration. Suppose a first consecutive DL transmission starts at S1 (which means that the first symbol for DL transmission is S1). and ends at E1 (which means that the last symbol for DL transmission is E1-<NUM>), a second consecutive DL transmission which immediately follows the first consecutive DL transmission starts at S2, and ends at E2, and a third consecutive DL transmission which immediately follows the second consecutive DL transmission starts at S3, and ends at E3. As shown in <FIG>, S1 is <NUM>, El is <NUM>, S2 is <NUM>, E2 is <NUM>, S3 is <NUM>, and E3 is <NUM>.

There are different options for determining the duration of the mapping. In the first option, the starting position of the duration is determined as the middle symbol between ending of a previous consecutive DL (i.e. E1) and starting of the current consecutive DL (i.e. S2). For example, the middle symbol may be calculated by an equation "floor ((E1+S2+<NUM>×k)/<NUM>), wherein k equals slot number of S2 minus slot number of E1". If the result is between <NUM> and <NUM>, the starting position will be the symbol number of the result with the slot number of El; and if the result is between <NUM> and <NUM>, the starting position will be the symbol number of "the result minus <NUM>" with the slot number of E1 plus <NUM>; and if the result is between <NUM> and <NUM>, the starting position will be the symbol number of "the result minus <NUM>" with the slot number of E1 plus <NUM>; and so on. The ending position of the duration is determined as the middle symbol between ending of the current consecutive DL (e.g. E2) and starting of a next consecutive DL (e. For example, the middle symbol may be calculated by an equation "floor ((E2+S3+<NUM>×k)/<NUM>), wherein k equals slot number of S3 minus slot number of E2". If the result is between <NUM> and <NUM>, the starting position will be the symbol number of the result with the slot number of E2; and if the result is between <NUM> and <NUM>, the starting position will be the symbol number of "the result minus <NUM>" with the slot number of E2 plus <NUM>; and if the result is between <NUM> and <NUM>, the starting position will be the symbol number of "the result minus <NUM>" with the slot number of E2 plus <NUM>; and so on.

In the example of <FIG>, El is <NUM>; S2 is <NUM>; slot number of S2 is <NUM>; and slot number of El is <NUM>. Accordingly, the result is floor ((<NUM>+<NUM>+<NUM>× (<NUM>-<NUM>))/<NUM>) = <NUM>. Therefore, the starting position of the duration is symbol <NUM> of slot <NUM>. Similarly, in the example of <FIG>, E2 is <NUM>; S3 is <NUM>; slot number of S3 is <NUM>; and slot number of E2 is <NUM>. Accordingly, the result is floor ((<NUM>+<NUM>+<NUM>× (<NUM>-<NUM>))/<NUM>) = <NUM>. Therefore, the ending position of the duration is symbol <NUM> of slot <NUM>.

As shown in the middle part of virtual index <NUM> slot of <FIG>, the duration of the mapping is from symbol <NUM> of slot <NUM> to symbol <NUM> of slot <NUM>, which means that the mapping is performed on symbols <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM>.

In a second option for determining the mapping duration, the starting position of a duration may be a predefined position between the end of a previous set of consecutive DL symbols (for example E1) and a starting position of the current set of consecutive DL symbols (for example S2). For example, for this second option, a slot boundary may correspond to such predefined position. If there are more than one slot boundary between ending position of a previous consecutive set of DL symbols and a starting position of the current consecutive set of DL symbols, the first or the last slot boundary may be determined as a predefined position. The ending position of a duration may also be a predefined position between the ending position of the current consecutive set of DL symbols (for example E2) and the starting position of the next consecutive set of DL symbols (for example S3). For example, the slot boundary may be a predefined position. If there are more than one slot boundary between ending of the current consecutive DL and starting of the next consecutive DL, the first or last slot boundary may be determined as the predefined position.

As shown in virtual index <NUM> slot of <FIG>, the boundary of the mapping is from symbol <NUM> of slot <NUM> to symbol <NUM> of slot <NUM>, which means that the mapping is performed on symbols <NUM>-<NUM> of slot <NUM>.

After determining the mapping boundaries (e.g. the start and the end positions), symbols located within such boundary (including the unavailable symbols and the available symbols) are mapped to the available symbols. In example of a PDCCH, the available symbols include those symbols that are indicated by the DCI format 2_0 as downlink symbols, for example, all of symbols indicated as "D" in the physical index <NUM> sequence of slot of <FIG>, e.g. symbols <NUM>-<NUM> of slot <NUM>, symbols <NUM>-<NUM> of slot <NUM> and symbols <NUM>-<NUM> of slot <NUM>; while the unavailable symbols include those symbols that are indicated by the DCI format 2_0 as reserved symbols or uplink symbols, for example, all of symbols indicated as "F" and "U" in the physical index <NUM> of <FIG>.

The arrows in <FIG> show the mapping. First, the available symbols are mapped to themselves. The available symbols <NUM>-<NUM> of slot <NUM> are mapped to themselves, i.e. symbols <NUM>-<NUM> of slot <NUM>, in both the first option (the virtual index <NUM> of <FIG>) and the second option (the virtual index <NUM> of <FIG>). The mapping of the available symbols is not explicitly shown with arrows in <FIG>.

Then, the unavailable symbols are mapped to the available symbols in a circular manner. In the first option shown in the virtual index <NUM> of <FIG>, symbols <NUM> and <NUM> of slot <NUM> are mapped to symbols <NUM> and <NUM> of slot <NUM> (e.g. the first two symbols among the available symbols), symbols <NUM>-<NUM> of slot <NUM> are mapped to symbols <NUM>-<NUM> of slot <NUM> (e.g. the remaining four symbols among the available symbols), and symbols <NUM> and <NUM> of slot <NUM> are mapped to symbols <NUM> and <NUM> of slot <NUM> (as all of six available symbols have been mapped, the first two available symbols are circularly mapped for the second time).

In the second option shown in the virtual index <NUM> of <FIG>, symbols <NUM>-<NUM> of slot <NUM> are mapped to symbols <NUM>-<NUM> of slot <NUM>, symbols <NUM>-<NUM> of slot <NUM> are mapped to symbols <NUM>-<NUM> of slot <NUM>, and symbols <NUM>-<NUM> of slot <NUM> are mapped to symbols <NUM>-<NUM> of slot <NUM>.

<FIG> shows a detailed mapping. Suppose that the RRC configured PDCCH would be transmitted in symbols <NUM> and <NUM> of slot <NUM>. However, according to the DCI format 2_0, the symbols <NUM> and <NUM> of slot <NUM> are unavailable. Therefore, the child node would, based on the mapping rule described with reference to <FIG>, map the symbols <NUM> and <NUM> of slot <NUM> to available symbols that can be used for PDCCH of the access link.

According to the first option of mapping, with reference to the physical index <NUM> and virtual index <NUM> of <FIG>, symbols <NUM> and <NUM> of slot <NUM> are mapped to symbols <NUM> and <NUM> of slot <NUM>. Therefore, as shown in the physical index <NUM> of <FIG>, the PDCCH would be transmitted in symbols <NUM> and <NUM> of slot <NUM>.

According to the second option of mapping, with reference to the physical index <NUM> and virtual index <NUM> of <FIG>, symbols <NUM> and <NUM> of slot <NUM> are mapped to symbols <NUM> and <NUM> of slot <NUM>. Therefore, as shown in the physical index <NUM> of <FIG>, the PDCCH would be transmitted in symbols <NUM> and <NUM> of slot <NUM>.

According to such mapping, the PDCCH can now be transmitted in available symbols.

As the number of available symbols for transmission is determined according to DCI format 2_0, while the PDCCH is scheduled by RRC signaling configuration, there could be a situation in which there are more symbols configured by RRC signaling for transmitting on PDCCH than the available symbols. In such situation, more than one symbol configured for transmitting PDCCH would be mapped to the same available symbol. For example, in the first option shown in the virtual index <NUM> of <FIG>, symbol <NUM> of slot <NUM> and symbol <NUM> of slot <NUM> are both mapped to symbol <NUM> of slot <NUM>. In addition, symbol <NUM> of slot <NUM> is also mapped to itself, i.e. symbol <NUM> of slot <NUM>. For ease of discussion, symbol <NUM> of slot <NUM> and symbol <NUM> of slot <NUM> are referred to as being redirected, while symbol <NUM> of slot <NUM> is referred to as without being redirected.

In the condition that more than one symbol is mapped to the same available symbol, the symbol without being redirected has higher priority than the symbol being redirected. In addition, for the symbol <NUM> of slot <NUM> and the symbol <NUM> of slot <NUM>, both of which are being redirected, the symbol <NUM> of slot <NUM> has higher priority because it is before symbol <NUM> of slot <NUM> in timing. As a whole, the symbol with the highest priority would be transmitted. The symbol(s) with lower priority(ies) would be dropped.

In <FIG>, the child node is indicated as a base unit, and the UE is indicated as a remote unit. <FIG> illustrates the schematic diagram of the methods performed in the base unit and in the remote unit according to the second embodiment.

In step <NUM>, the base unit transmits DCI format 2_0 indicating the physical format of the symbols. In step <NUM>, the UE receives the DCI format 2_0. The physical format indicated in the DCI format 2_0 may be the physical format shown in the physical index <NUM> of <FIG>.

The periodicity of transmitting the DCI format 2_0 is predetermined. Each time the DCI format 2_0 is transmitted, the physical format of the symbols indicated in the DCI format 2_0 may change. In particular, the symbols assigned for a downlink transmission on the access link, the symbols assigned for an uplink transmission of the access link and the reserved symbols may change. Therefore, each time the remote unit receives a changed DCI format 2_0, the physical format associated with time domain resources may differ. Hence, the detailed mapping between the virtual format and the physical format may accordingly be changed.

In step <NUM>, the base unit transmits the RRC configuration of PDCCH. Alternatively, if a PUCCH transmission is necessary, the base unit transmits the RRC configuration for PUCCH. In step <NUM>, the remote unit receives such RRC configuration. For example, as shown in the RRC configured physical resource for PDCCH of <FIG>, the RRC configured PDCCH would be transmitted in symbols <NUM> and <NUM> of slot <NUM>.

In <FIG>, step <NUM>, RRC configuration is transmitted after step <NUM>, in which the DCI format 2_0 is transmitted. However, the transmission of the RRC configuration may be performed before the transmission of the DCI format 2_0, which means that step <NUM> may be performed before step <NUM>. As described earlier, the DCI format 2_0 changes more frequently than RRC configuration. Therefore, after the transmission of the RRC configuration, the DCI format 2_0 may be transmitted more than once before the transmission of another RRC configuration. As a result, the order and times associated with performing steps <NUM> and <NUM> are not limited to the order and times identified in <FIG>. The point is: when the determination of the physical symbols to be used for transmitting PDCCH is made (see the following step <NUM>), the physical symbols would be identified using the last (or most recently) transmitted DCI format 2_0.

In step <NUM>, the base unit determines the physical symbols to be used for transmitting PDCCH. As shown in <FIG>, if the first option of mapping is adopted, the PDCCH would be transmitted on symbols <NUM> and <NUM> of slot <NUM> (see the virtual index <NUM> and the physical index <NUM> of <FIG>); and if the second option of mapping is adopted, the PDCCH would be transmitted on symbols <NUM> and <NUM> of slot <NUM> (see the virtual index <NUM> and the physical index <NUM> of <FIG>).

In step <NUM>, the remote unit performs the same mapping as the base unit so that the remote unit knows on which physical symbol(s) PDCCH would be transmitted.

In step <NUM>, the base unit transmits PDCCH on the available symbol(s) mapped to in step <NUM>. In step <NUM>, the remote unit receives the PDCCH on the available symbol(s) identified as a result of mapping performed in step <NUM>. Incidentally, as described above, in the condition that the available mapped symbol(s) in step <NUM> would be used by other symbols due to their higher priority, the PDCCH that is redirected and has lower priority would be dropped and not transmitted in step <NUM>.

According to the methods described with reference to <FIG>, the base unit maps the symbols unavailable for transmitting PDCCH to available symbols according to the physical format indicated in the last received DCI format 2_0. The remote unit, upon receiving RRC configured PDCCH, performs the same mapping as the base unit so that it knows where the PDCCH would actually be transmitted. Therefore, even if a mismatch between the preconfigured PDCCH monitoring occasion and the slot format indicated by DCI format 2_0 occurs, the UE may successfully receive the PDCCH. This kind of behavior can be enabled by RRC signaling of the base unit. Once enabled, the mapping between physical resources to virtual resource will be performed at both the base unit side and the remote unit side; otherwise, no mapping will be performed.

The second embodiment is described with reference to PDCCH. Similarly, the second embodiment also applies to the PUCCH. In case of PUCCH, the available symbols include those symbols that are indicated by the DCI format 2_0 as uplink symbols while the unavailable symbols include those symbols that are indicated by the DCI format 2_0 as reserved symbols and downlink symbols.

Claim 1:
A method performed by a remote unit, the method comprising:
receiving (<NUM>) a first indicator indicating a plurality of first, physical, time domain resources, wherein the plurality of first, physical, time domain resources are fragmented, and wherein the first indicator is in DCI format 2_0;
receiving (<NUM>) a second indicator indicating a second, virtual, time domain resource allocated for data or control channel transmission, wherein the second indicator is a downlink grant, an uplink grant, or an RRC configuration;
mapping (<NUM>) the second, virtual, time domain resource to a third, physical, time domain resource, wherein the third, physical, time domain resource is a subset of the first, physical, time domain resources, and such that the fragmented first, physical, time domain resources are aggregated to be scheduled together; and
receiving (<NUM>) the data or control channel transmission from the third, physical, time domain resource.