FIELD

The present disclosure relates to wireless communications, and in particular, to cross-carrier scheduling with downlink control information (DCI) handling.

INTRODUCTION

Carrier Aggregation

Carrier Aggregation (CA) is generally used in 3rd Generation Partnership Project (3GPP) New Radio (NR, also referred to as 5th Generation (5G)) and Long Term Evolution (LTE, also referred to as 4th Generation (4G)) systems to improve wireless device transmit/receive data rate as compared to systems which do not use CA. With CA, the wireless device typically operates initially on a single serving cell referred to as a primary cell (Pcell). The Pcell is operated on a component carrier in a frequency band. The wireless device is then configured by the network/network node with one or more secondary serving cells (SCell(s)). Each SCell can correspond to a component carrier (CC) in the same frequency band (intra-band CA) or a different frequency band (inter-band CA) from the frequency band of the CC corresponding to the Pcell. For the wireless device to transmit/receive data on the SCell(s) (e.g., by receiving downlink (DL)-shared channel (SCH) information on a physical downlink shared channel (PDSCH) or by transmitting uplink-shared channel (UL-SCH) information/data on a physical uplink shared channel (PUSCH)), the SCell(s) may need to be activated by the network/network node. The SCell(s) can also be deactivated and later reactivated as needed via activation/deactivation signaling.

Cross-Carrier Scheduling

For NR carrier aggregation, cross-carrier scheduling (CCS) has been considered using the following framework:

- 1. The wireless device has a primary serving cell and can be configured with one or more secondary serving cells (SCells).
- 2. For a given SCell with SCell index X,
- a. if the SCell is configured with a ‘scheduling cell’ with cell index Y (i.e., cross-carrier scheduling)
  - i. SCell X is referred to as the ‘scheduled cell’.
  - ii. The wireless device monitors DL PDCCH on the scheduling cell Y for assignments/grants scheduling PDSCH/PUSCH corresponding to Sell X.
  - iii. PDSCH/PUSCH corresponding to SCell X cannot be scheduled for the wireless device using a serving cell other than scheduling cell Y.
- b. Otherwise
  - i. SCell X is the scheduling cell for SCell X (i.e., same-carrier scheduling)
  - ii. The wireless device monitors DL PDCCH on SCell X for assignments/grants scheduling PDSCH/PUSCH corresponding to SCell X
  - iii. PDSCH/PUSCH corresponding to SCell X may not be able to be scheduled for the wireless device using a serving cell other than SCell X
- 3. An SCell may not be able to be configured as a scheduling cell for the primary cell as the primary cell may always be its own scheduling cell.

With current CA and cross-carrier scheduling framework, a SCell cannot be used for scheduling physical shared data channels such as PDSCH/PUSCH on the PCell. Adding additional scheduling cells for the PCell will require ways to handle the increase in wireless device capability that is needed for the increase in PDCCH monitoring and decoding.

SUMMARY

Some embodiments advantageously provide methods, systems, and apparatuses for cross-carrier scheduling with downlink control information (DCI) handling.

In one embodiment there is provided a network node. The network node operating a secondary cell and is configured to communicate with a wireless device and a primary cell for the wireless device. The network node includes a radio interface and processing circuitry configured to schedule a physical shared channel on the primary cell for the wireless device using a physical downlink control channel, PDCCH, on the primary cell and a physical downlink control channel, PDCCH, on the secondary cell.

In one embodiment there is provided a method. The method is implemented in a network node that is operating as a secondary cell and that is configured to communicate with a wireless device and a primary cell for the wireless device. The method includes scheduling a physical shared channel the primary cell for the wireless device using a physical downlink control channel, PDCCH, on the primary cell and a physical downlink control channel, PDCCH, on the secondary cell.

In one embodiment there is provided a wireless device. The wireless device configured to communicate with a primary cell and a secondary cell. Further the wireless device includes a radio interface and processing circuitry configured to receive scheduling from the primary cell using a PDCCH and scheduling from the secondary cell using a PDCCH, the scheduling configured to schedule a physical shared channel on the primary cell for the wireless device.

In one embodiment there is provided a method. The method implemented by a wireless device that is configured to communicate with a primary cell and a secondary cell. The method includes receiving scheduling from the primary cell using a PDCCH and receiving a scheduling from the secondary cell using a PDCCH, the scheduling configured to schedule a physical shared channel on the primary cell for the wireless device.

Further embodiments include a network node, where the DCI size budget for the primary cell scheduled by the primary cell and secondary cell is same as the DCI size budget for the primary cell scheduled by a single cell. Thus, the total DCI size budget for primary cell and the secondary cell does not increase compared to case where the PDSCH for the primary cell is scheduled by only the primary. Adding a secondary cell to the scheduling of the primary cell such that both the primary cell and the secondary cell may schedule the PDSCH or PUSCH on the primary cell does not increase the DCI size budget.

In further embodiments the DCI size budget for the secondary cell scheduling a primary cell and secondary cell scheduling a secondary cell is same as the DCI size budget for the secondary cell scheduled by single cell.

In other embodiments the wherein the DCI format used for the primary cell and the DCI format used for the secondary cell is sized matched, e.g. the DCI for the primary cell and the DCI format used for the secondary cell has the same size. This is achieved e.g. by padding by including a carrier indicator field in the DCI format used for the primary cell.

A PCell can normally only be scheduled by the PCell. For a wireless device there is normally an upper limit on the number of different DCI sizes that the wireless can monitor The embodiments enable an SCell to be used for scheduling PDSCH/PUSCH on the PCell by restricting the DCI, for example restricting the number of different DCI sizes. Adding one or more scheduling cells for the PCell, the SCell in this case could otherwise necessitate an increase in the BDs/CCEs budget. An increase in the BDs/CCEs budget would then require more wireless device processing and computational power and could also require increased wireless device complexity.

In one or more embodiments, one or more of the following are provided: applying an aggregate budget over a set of scheduling cases (e.g., over all DCIs for the primary cell or overall DCIs monitored on SCell that schedules primary cell) and/or applying restrictions on the monitoring of some DCIs for the primary cell in different scheduling cells. In some embodiments, a carrier indicator field is introduced for some DCI formats monitored on the primary cell even though the primary cell is not the scheduling cell for any other SCell. In some embodiments, when the SCell is a DL-only SCell, one or more of the unused UL DCI formats (or size budget) available in the SCell are utilized for scheduling primary cell uplink without the need for CIF in DCI formats.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic diagram of an example network architecture illustrating a communication system connected via an intermediate network to a host computer according to the principles in the present disclosure;

FIG. 2 is a block diagram of a host computer communicating via a network node with a wireless device over an at least partially wireless connection according to some embodiments of the present disclosure;

FIG. 3 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for executing a client application at a wireless device according to some embodiments of the present disclosure;

FIG. 4 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a wireless device according to some embodiments of the present disclosure;

FIG. 5 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data from the wireless device at a host computer according to some embodiments of the present disclosure;

FIG. 6 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a host computer according to some embodiments of the present disclosure;

FIG. 7 is a flowchart of an example process in a network node according to some embodiments of the present disclosure;

FIG. 8 is a flowchart of an example process in a wireless device according to some embodiments of the present disclosure;

FIG. 9 is a diagram of a DSS scenario according to some embodiments of the present disclosure;

FIGS. 10a-c are diagrams of different scenarios of a scheduling cell according to some embodiments of the disclosure;

FIG. 11 is a diagram of an example of DCI format monitoring according to some embodiments of the disclosure;

FIG. 12 is a diagram of another example of DCI format monitoring according to some embodiments of the disclosure;

FIG. 13 is a diagram of an example of DCI budgeting according to some embodiments of the disclosure; and

FIG. 14 is a diagram of an example of DCI scheduling according to some embodiments of the disclosure.

DETAILED DESCRIPTION

In one or more embodiments, described herein advantageously enable/configure a SCell to be used for scheduling PDSCH/PUSCH on the primary cell with a DCI size budget handling with reduced complexity as well as, in some cases, improved performance where overhead due to carrier indicator field can be avoided.

Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to cross-carrier scheduling with DCI handling Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node.

In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein can be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device etc.

Also, in some embodiments the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell/multicast Coordination Entity (MCE), IAB node, relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and/or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Embodiments provide cross-carrier scheduling with DCI handling. Referring now to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 1 a schematic diagram of a communication system 10, according to an embodiment, such as a 3GPP-type cellular network that may support standards such as LTE and/or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include many more WDs 22 and network nodes 16.

Also, it is contemplated that a WD 22 can be in simultaneous communication and/or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 can have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, WD 22 can be in communication with an eNB for LTE/E-UTRAN and a gNB for NR/NG-RAN.

The communication system 10 may itself be connected to a host computer 24, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 24 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 26, 28 between the communication system 10 and the host computer 24 may extend directly from the core network 14 to the host computer 24 or may extend via an optional intermediate network 30. The intermediate network 30 may be one of, or a combination of more than one of, a public, private or hosted network. The intermediate network 30, if any, may be a backbone network or the Internet. In some embodiments, the intermediate network 30 may comprise two or more sub-networks (not shown).

The communication system of FIG. 1 as a whole enables connectivity between one of the connected WDs 22a, 22b and the host computer 24. The connectivity may be described as an over-the-top (OTT) connection. The host computer 24 and the connected WDs 22a, 22b are configured to communicate data and/or signaling via the OTT connection, using the access network 12, the core network 14, any intermediate network 30 and possible further infrastructure (not shown) as intermediaries. The OTT connection may be transparent in the sense that at least some of the participating communication devices through which the OTT connection passes are unaware of routing of uplink and downlink communications. For example, a network node 16 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 24 to be forwarded (e.g., handed over) to a connected WD 22a. Similarly, the network node 16 need not be aware of the future routing of an outgoing uplink communication originating from the WD 22a towards the host computer 24.

A network node 16 is configured to include an enhancement unit 32 which is configured to perform one or more network node 16 functions as described herein such as with respect to cross-carrier scheduling with DCI handling. A wireless device 22 is configured to include an operation unit 34 which is configured to perform one or more wireless device 22 functions as described herein such as with respect to cross-carrier scheduling with DCI handling.

Example implementations, in accordance with an embodiment, of the WD 22, network node 16 and host computer 24 discussed in the preceding paragraphs will now be described with reference to FIG. 2. In a communication system 10, a host computer 24 comprises hardware (HW) 38 including a communication interface 40 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 10. The host computer 24 further comprises processing circuitry 42, which may have storage and/or processing capabilities. The processing circuitry 42 may include a processor 44 and memory 46. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 42 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 44 may be configured to access (e.g., write to and/or read from) memory 46, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Processing circuitry 42 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by host computer 24. Processor 44 corresponds to one or more processors 44 for performing host computer 24 functions described herein. The host computer 24 includes memory 46 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 48 and/or the host application 50 may include instructions that, when executed by the processor 44 and/or processing circuitry 42, causes the processor 44 and/or processing circuitry 42 to perform the processes described herein with respect to host computer 24. The instructions may be software associated with the host computer 24.

The software 48 may be executable by the processing circuitry 42. The software 48 includes a host application 50. The host application 50 may be operable to provide a service to a remote user, such as a WD 22 connecting via an OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the remote user, the host application 50 may provide user data which is transmitted using the OTT connection 52. The “user data” may be data and information described herein as implementing the described functionality. In one embodiment, the host computer 24 may be configured for providing control and functionality to a service provider and may be operated by the service provider or on behalf of the service provider. The processing circuitry 42 of the host computer 24 may enable the host computer 24 to observe, monitor, control, transmit to and/or receive from the network node 16 and or the wireless device 22. The processing circuitry 42 of the host computer 24 may include an information unit 54 configured to enable the service provider to process, store, transmit, receive, forward, relay, determine, configure, reconfigure, etc., information related to cross-carrier scheduling with DCI handling that is described herein.

The communication system 10 further includes a network node 16 provided in a communication system 10 and including hardware 58 enabling it to communicate with the host computer 24 and with the WD 22. The hardware 58 may include a communication interface 60 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 10, as well as a radio interface 62 for setting up and maintaining at least a wireless connection 64 with a WD 22 located in a coverage area 18 served by the network node 16. The radio interface 62 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers. The communication interface 60 may be configured to facilitate a connection 66 to the host computer 24. The connection 66 may be direct or it may pass through a core network 14 of the communication system 10 and/or through one or more intermediate networks 30 outside the communication system 10.

In the embodiment shown, the hardware 58 of the network node 16 further includes processing circuitry 68. The processing circuitry 68 may include a processor 70 and a memory 72. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 68 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 70 may be configured to access (e.g., write to and/or read from) the memory 72, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the network node 16 further has software 74 stored internally in, for example, memory 72, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 74 may be executable by the processing circuitry 68. The processing circuitry 68 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by network node 16. Processor 70 corresponds to one or more processors 70 for performing network node 16 functions described herein. The memory 72 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 74 may include instructions that, when executed by the processor 70 and/or processing circuitry 68, causes the processor 70 and/or processing circuitry 68 to perform the processes described herein with respect to network node 16. For example, processing circuitry 68 of the network node 16 may include enhancement unit 32 configured to perform one or more network node 16 functions as described herein such as with respect to cross-carrier scheduling with DCI handling.

The communication system 10 further includes the WD 22 already referred to. The WD 22 may have hardware 80 that may include a radio interface 82 configured to set up and maintain a wireless connection 64 with a network node 16 serving a coverage area 18 in which the WD 22 is currently located. The radio interface 82 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

The hardware 80 of the WD 22 further includes processing circuitry 84. The processing circuitry 84 may include a processor 86 and memory 88. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 84 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 86 may be configured to access (e.g., write to and/or read from) memory 88, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the WD 22 may further comprise software 90, which is stored in, for example, memory 88 at the WD 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 22. The software 90 may be executable by the processing circuitry 84. The software 90 may include a client application 92. The client application 92 may be operable to provide a service to a human or non-human user via the WD 22, with the support of the host computer 24. In the host computer 24, an executing host application 50 may communicate with the executing client application 92 via the OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the user, the client application 92 may receive request data from the host application 50 and provide user data in response to the request data. The OTT connection 52 may transfer both the request data and the user data. The client application 92 may interact with the user to generate the user data that it provides.

The processing circuitry 84 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD 22. The processor 86 corresponds to one or more processors 86 for performing WD 22 functions described herein. The WD 22 includes memory 88 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 90 and/or the client application 92 may include instructions that, when executed by the processor 86 and/or processing circuitry 84, causes the processor 86 and/or processing circuitry 84 to perform the processes described herein with respect to WD 22. For example, the processing circuitry 84 of the wireless device 22 may include an operation unit 34 configured to perform one or more wireless device 22 functions as described herein such as with respect to cross-carrier scheduling with DCI handling.

Dual Connectivity

Dual Connectivity (DC) is generally used in NR (5G) and LTE systems to help improve wireless device transmit and receive data rates. With DC, the wireless device typically operates with a master cell group (MCG) and a secondary cell group (SCG). Each cell group can have one or more serving cells. The MCG cell, operating on the primary frequency, in which the wireless device either performs the initial connection establishment procedure or initiates the connection re-establishment procedure, is referred to as the primary cell or PCell. The SCG cell in which the wireless device performs random access when performing the Reconfiguration with Sync procedure is referred to as the primary SCG cell or PSCell.

In some cases, the term “primary cell” or “primary serving cell” can refer to PCell for a wireless device not configured with DC, and/or can refer to PCell of MCG or PSCell of SCG for a wireless device configured with DC.

PDCCH Monitoring

In third generation partnership project (3GPP) NR standards, downlink control information (DCI) is received over the physical (i.e., physical layer) downlink control channel (PDCCH). The PDCCH may carry DCI in messages with different formats. DCI format 0_0, 0_1, and 0_2, for example, are DCI messages used to convey uplink grants to the wireless device for transmission of the physical (i.e., physical layer) data channel in the uplink (PUSCH) and DCI format 1_0, 1_1, and 1_2, for example, are used to convey downlink grants for transmission of the physical layer data channel in the downlink (PDSCH). Other DCI formats (e.g., DCI 2_0, 2_1, 2_2 and 2_3) are used for other purposes such as transmission of slot format information, reserved resource, transmit power control information, etc.

A PDCCH candidate is searched within a common or wireless device-specific search space which is mapped to a set of time and frequency resources referred to as a control resource set (CORESET). The search spaces within which PDCCH candidates may be required to be monitored and are configured/indicated to the wireless device via radio resource control (RRC) signaling. A monitoring periodicity is also configured for different PDCCH candidates. In any particular slot, the wireless device may be configured to monitor multiple PDCCH candidates in multiple search spaces which may be mapped to one or more CORESETs. PDCCH candidates may need to be monitored multiple times in a slot, once every slot or once in multiple of slots.

The smallest unit used for defining CORESETs is a Resource Element Group (REG) which is defined as spanning 1 PRB×1 OFDM symbol in frequency and time. Each REG contains demodulation reference signals (DM-RS) to aid in the estimation of the radio channel over which that REG was transmitted. When transmitting the PDCCH, a precoder could be used to apply weights at the transmit antennas based on some knowledge of the radio channel prior to transmission. It is possible to improve channel estimation performance at the wireless device by estimating the channel over multiple REGs that are proximate in time and frequency if the precoder used at the transmitter for the REGs is not different. To assist the wireless device with channel estimation, the multiple REGs can be grouped together to form a REG bundle and the REG bundle size for a CORESET is indicated to the wireless device. The wireless device may assume that any precoder used for the transmission of the PDCCH is the same for all the REGs in the REG bundle. A REG bundle may consist of 2, 3 or 6 REGs.

A control channel element (CCE) may consist of 6 REGs. The REGs within a CCE may either be contiguous or distributed in frequency. When the REGs are distributed in frequency, the CORESET is said to be using an interleaved mapping of REGs to a CCE and if the REGs are not distributed in frequency, a non-interleaved mapping is said to be used.

A PDCCH candidate may span 1, 2, 4, 8 or 16 CCEs. The number of aggregated CCEs used is referred to as the aggregation level for the PDCCH candidate.

A hashing function is used to determine the CCEs corresponding to PDCCH candidates that a wireless device may have to monitor within a search space set. The hashing can be done/determined/performed differently for different wireless devices so that the CCEs used by the wireless devices are randomized and the probability of collisions between multiple wireless devices for which PDCCH messages are included in a CORESET is reduced.

Blind decoding (BD) of potential PDCCH transmissions is attempted by the wireless device in each of the configured PDCCH candidates within a slot. The complexity incurred, at the wireless device, to perform the blind decoding may depend on a number of blind decoding attempts and the number of CCEs which need to be processed.

In order to manage complexity, limits on the total number of CCEs and/or total number of blind decodes to be processed by the wireless device have been discussed and a possible technique for BD/CCE partitioning based on wireless device capability has been adopted for NR operation with multiple component carriers.

Blind Decoding and CCE Handling for Carrier Aggregation

In existing NR standards, a scheduled cell has only one scheduling cell where the primary cell may always perform the scheduling for the primary cell. A scheduling cell carries DCI for scheduling itself and can carry DCI for scheduling other cells. When a wireless device is configured with cross-carrier scheduling, the PDCCH carrying the DCI format for scheduling the PDSCH/PUSCH on the scheduled cell is sent on a scheduling cell. In such a case, a carrier indicator field is included in the DCI formats (e.g., non-fallback DCI formats such as 0-1/1-1 for scheduling PUSCH/PDSCH) on the scheduling cell. Higher layer configuration indicates the linkages between the scheduled/scheduling cells, the CIF value to monitor, and the corresponding search space configuration for monitoring DCI formats of a scheduled cell on the scheduling cell, etc.

A wireless device can be configured with up to three CORESETs and up to ten search spaces for each DL bandwidth part (BWP) in a scheduling cell. The network node can configure the search spaces that a wireless device monitors according to some constraints or limits on maximum number of blind decodes and control channel elements.

DCI Size Budget

In NR 3GPP Release 15 (Rel-15), for each BWP of a scheduled cell, there is an upper limit on the number of different DCI sizes that the wireless device can monitor. The wireless device may not be expected to handle a configuration that results in 1) the total number of different DCI sizes configured to monitor is more than 4 for the cell or 2) the total number of different DCI sizes with C-RNTI configured to monitor is more than 3 for the cell.

A size-matching procedure is defined for some DCIs (e.g., 0-0/1-0/1-1/0-1 in some search spaces) which can be used to ensure the DCI size budget is not exceeded. For some DCIs such as 2-0, 2-6, the DCI size is explicitly configured by higher layers, but the network node may configure such that wireless budget is not exceeded.

Default QCL Assumption in Cross-Carrier Scheduling

In case of cross-carrier scheduling, the PDCCH to PDSCH gap is less than a certain threshold, the default TCI state to assume for that PDSCH can be given by the TCI state with lowest index of the TCI states configured for the PDSCH.

In some embodiments, the inner workings of the network node 16, WD 22, and host computer 24 may be as shown in FIG. 2 and independently, the surrounding network topology may be that of FIG. 1.

In FIG. 2, the OTT connection 52 has been drawn abstractly to illustrate the communication between the host computer 24 and the wireless device 22 via the network node 16, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the WD 22 or from the service provider operating the host computer 24, or both. While the OTT connection 52 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 64 between the WD 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the WD 22 using the OTT connection 52, in which the wireless connection 64 may form the last segment. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and/or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc.

In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 52 between the host computer 24 and WD 22, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 52 may be implemented in the software 48 of the host computer 24 or in the software 90 of the WD 22, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 52 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 48, 90 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 52 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the network node 16, and it may be unknown or imperceptible to the network node 16. Some such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary WD signaling facilitating the host computer's 24 measurements of throughput, propagation times, latency and the like. In some embodiments, the measurements may be implemented in that the software 48, 90 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 52 while it monitors propagation times, errors etc.

Thus, in some embodiments, the host computer 24 includes processing circuitry 42 configured to provide user data and a communication interface 40 that is configured to forward the user data to a cellular network for transmission to the WD 22. In some embodiments, the cellular network also includes the network node 16 with a radio interface 62. In some embodiments, the network node 16 is configured to, and/or the network node's 16 processing circuitry 68 is configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/supporting/ending a transmission to the WD 22, and/or preparing/terminating/maintaining/supporting/ending in receipt of a transmission from the WD 22.

In some embodiments, the host computer 24 includes processing circuitry 42 and a communication interface 40 that is configured to a communication interface 40 configured to receive user data originating from a transmission from a WD 22 to a network node 16. In some embodiments, the WD 22 is configured to, and/or comprises a radio interface 82 and/or processing circuitry 84 configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/supporting/ending a transmission to the network node 16, and/or preparing/terminating/maintaining/supporting/ending in receipt of a transmission from the network node 16.

Although FIGS. 1 and 2 show various “units” such as enhancement unit 32, and operation unit 34 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG. 3 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIGS. 1 and 2, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIG. 2. In a first step of the method, the host computer 24 provides user data (Block S100). In an optional substep of the first step, the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50 (Block S102). In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block S104). In an optional third step, the network node 16 transmits to the WD 22 the user data which was carried in the transmission that the host computer 24 initiated, in accordance with the teachings of the embodiments described throughout this disclosure (Block S106). In an optional fourth step, the WD 22 executes a client application, such as, for example, the client application 92, associated with the host application 50 executed by the host computer 24 (Block S108).

FIG. 4 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 1, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 1 and 2. In a first step of the method, the host computer 24 provides user data (Block S110). In an optional substep (not shown) the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50. In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block S112). The transmission may pass via the network node 16, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step, the WD 22 receives the user data carried in the transmission (Block S114).

FIG. 5 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 1, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 1 and 2. In an optional first step of the method, the WD 22 receives input data provided by the host computer 24 (Block S116). In an optional substep of the first step, the WD 22 executes the client application 92, which provides the user data in reaction to the received input data provided by the host computer 24 (Block S118). Additionally or alternatively, in an optional second step, the WD 22 provides user data (Block S120). In an optional substep of the second step, the WD provides the user data by executing a client application, such as, for example, client application 92 (Block S122). In providing the user data, the executed client application 92 may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the WD 22 may initiate, in an optional third substep, transmission of the user data to the host computer 24 (Block S124). In a fourth step of the method, the host computer 24 receives the user data transmitted from the WD 22, in accordance with the teachings of the embodiments described throughout this disclosure (Block S126).

FIG. 6 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 1, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 1 and 2. In an optional first step of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 16 receives user data from the WD 22 (Block S128). In an optional second step, the network node 16 initiates transmission of the received user data to the host computer 24 (Block S130). In a third step, the host computer 24 receives the user data carried in the transmission initiated by the network node 16 (Block S132).

FIG. 7 is a flowchart of an example process in a network node 16 according to some embodiments of the present disclosure. One or more Blocks and/or functions performed by network node 16 may be performed by one or more elements of network node 16 such as by enhancement unit 32 in processing circuitry 68, processor 70, radio interface 62, etc. In one or more embodiments, network node 16 such as via one or more of processing circuitry 68, processor 70, enhancement unit 32, communication interface 60 and radio interface 62 is configured to schedule (Block S134) a physical shared channel such as a PDSCH or a PUSCH on the primary cell for the wireless 22 device using a PDCCH on the primary cell and a PDCCH on the secondary cell, as described herein. In one or more embodiments, network node 16 such as via one or more of processing circuitry 68, processor 70, enhancement unit 32, communication interface 60 and radio interface 62 is configured to optionally cause (Block S136) transmission of the scheduling, as described herein.

According to one or more embodiments, the scheduling of at least one of the physical shared channel and physical control channel on the primary cell is performed by a physical downlink control channel, PDCCH, on the secondary cell. According to one or more embodiments, a downlink control information, DCI, budget for the wireless device for both the primary cell and secondary cell corresponds to a total number of DCIs sizes that the wireless device is provided is shared among the primary cell and is the same as the DCI budget for one of the primary cell and secondary cell.

FIG. 8 is a flowchart of an example process in a wireless device 22 according to some embodiments of the present disclosure. One or more Blocks and/or functions performed by wireless device 22 may be performed by one or more elements of wireless device 22 such as by operation unit 34 in processing circuitry 84, processor 86, radio interface 82, etc. In one or more embodiments, wireless device such as via one or more of processing circuitry 84, processor 86, operation unit 34 and radio interface 82 is configured to receive (Block S138) receive scheduling from the primary cell using a PDCCH and receiving scheduling from the secondary cell using a PDCCH, the scheduling is configured to schedule a physical shared channel such as PDSCH or PUSCH on the primary cell for the wireless device, as described herein. In one or more embodiments, wireless device such as via one or more of processing circuitry 84, processor 86, operation unit 34 and radio interface 82 is configured to optimally operate (Block S140) according to the received scheduling, as described herein.

According to one or more embodiments, the scheduling of at least one of the physical shared channel and physical control channel on the primary cell is received via a physical downlink control channel, PDCCH, on the secondary cell. According to one or more embodiments, a downlink control information, DCI, budget for the wireless device 22 for both the primary cell and secondary cell corresponds to a total number of DCIs sizes that the wireless device 22 is provided is shared among the primary cell and is the same as the DCI budget for one of the primary cell and secondary cell.

Having generally described arrangements for cross-carrier scheduling with DCI handling, details for these arrangements, functions and processes are provided as follows, and which may be implemented by the network node 16, wireless device 22 and/or host computer 24.

Embodiments Provide Cross-Carrier Scheduling with DCI Handling.

DSS Scenario and Enhanced CCS Framework

FIG. 9 is a diagram of an example DSS scenario. FIG. 9 illustrates slots for a NR PCell/PSCell (primary cell) provided by, for example, network node 16, for a DL CA capable wireless device 22 operated on a carrier where the same carrier is also used for serving wireless devices of a different radio access technology (e.g., LTE (4G)) via dynamic spectrum sharing, and slots for another NR SCell configured for the same wireless device.

As shown in FIG. 9, when a NR primary cell is operated on the same carrier on which legacy LTE wireless devices 22 are served, the opportunities for transmitting PDCCH may be significantly limited due to the need to avoid overlap with LTE transmissions (e.g., LTE PDCCH, LTE PDSCH, LTE CRS).

For a wireless device 22 supporting DL CA, providing the ability to use SCell PDCCH to schedule primary cell PDSCH/PUSCH (e.g., as shown by dashed arrows in FIG. X1) helps in reducing the loading of primary cell PDCCH.

The example illustrated in FIG. 9 is for a CA scenario for a DL CA capable wireless device 22 with NR primary cell on FDD carriers with 15 kHz SCS and NR SCell on TDD carrier with 30 kHz SCS. This is just one scenarios, where the teachings described herein are equally applicable to other scenarios (e.g., SCell being operated on FDD band) with 15 kHz SCS are also possible.

Enhanced CCS Framework with Special SCell (sSCell)

To enable/configure support of SCell scheduling such as via one or more of processing circuitry 68, processor 70, radio interface 62, enhancement unit 32, etc., PDSCH/PUSCH on primary cell, the existing NR CCS framework can be enhanced/configured/modified as follows:

- 1. In one or more embodiments, the network node 16 may RRC configure a DL CA capable wireless device 22 with at least one SCell such that PDCCH on that SCell can schedule PUSCH and/or PDSCH on the primary cell. Such an SCell is referred to as, e.g., a special SCell (sSCell).
- 2. When wireless device 22 is configured with sSCell:
  - a. PDCCH on primary cell may only schedule PDSCH/PUSCH transmissions on the primary cell (no CCS may be allowed from primary cell);
  - b. PDCCH on sSCell can schedule such as via one or more of processing circuitry 68, processor 70, radio interface 62, enhancement unit 32, etc., PDSCH/PUSCH on
    - i. the primary cell of the cell group (CG) of the sSCell;
    - ii. the sSCell (i.e., sSCell cannot be a ‘scheduled cell’ for another cell); and/or
    - iii. other SCells in the same CG of sSCell for which the sSCell is configured as a scheduling cell;
  - c. the primary cell can be considered to have ‘two scheduling cells’, i.e., the primary cell itself and the sSCell. Other serving cells may only have one scheduling cell.

Above conditions simplify sSCell operation without reducing flexibility. For example, the main motivation of sSCell is to reduce PDCCH load on primary cell and supporting CCS from primary cell would only increase PDCCH load. So, such combination is not required when sSCell is configured.

Blind Decoding and CCE Handling for Enhanced Cross-Carrier Scheduling

The wireless device 22 typically uses such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., the primary cell for initial access, link maintenance, and overall as an anchor cell for maintaining a network connection. The wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., may always monitor the primary cell and the primary cell may always be a scheduling cell and may always be activated.

Enhanced cross-carrier scheduling is where a SCell such as via one or more of processing circuitry 68, processor 70, radio interface 62, enhancement unit 32, etc., can also schedule transmission/reception on the primary cell which can reduce the loading on the PDCCH of the primary cell. One feature of enhanced cross-carrier scheduling is that the primary cell has two scheduling cells—the primary cell, itself, and an SCell (i.e., sSCell) that can also schedule the primary cell. In this case, one or more of the BD/CCE limits may be identified as the:

- Maximum number of BDs/CCEs supported on the primary cell;
- Maximum number of BDs/CCEs supported on the secondary cell for scheduling the primary cell;
- Maximum number of BDs/CCEs supported on the secondary cell for scheduling the secondary cell; and/or
- Maximum number of BDs/CCEs supported for scheduling the other secondary cells.

Based on one or more of the identified limits above, the network node 16/network can configure PDCCH candidates appropriately for the different search spaces on different serving cells.

Some examples are illustrated in FIGS. 10a-c where arrows denote the scheduling cell, scheduled cell relationship, and where the origin of the dashed line illustrates the scheduling cell, and where a scheduled cell pair are grouped with another pair of (scheduling cell, scheduled cell) for the purpose of BD/CCE limit calculation.

In FIG. 10a, the primary cell is considered as the reference scheduling cell, and the primary cell that schedules primary cell communications and the sSCell that schedules such as via one or more of processing circuitry 68, processor 70, radio interface 62, enhancement unit 32, etc., primary cell communications may share the same BD/CCE budget that is determined using the primary cell scheduling primary cell as reference.

In FIG. 10b, the sSCell is considered the reference scheduling cell, and the sSCell 1 that schedules such as via one or more of processing circuitry 68, processor 70, radio interface 62, enhancement unit 32, etc., the primary cell and the primary cell that schedules the primary cell share the same BD/CCE budget that is determined using the sSCell scheduling primary cell as the reference.

In FIG. 10c, the primary cell is considered as the reference scheduling cell, and the sSCell that schedules such as via one or more of processing circuitry 68, processor 70, radio interface 62, enhancement unit 32, etc., the sSCell and the sSCell such as via one or more of processing circuitry 68, processor 70, radio interface 62, enhancement unit 32, etc., that schedules the primary cell share the same BD/CCE budget that is determined using the sSCell scheduling sSCell as reference.

DCIs and Search Space Types that May be Allowed/not Allowed for Two Cells Scheduling Same Cell

NR supports common search spaces and wireless device 22-specific search spaces. A common search space can be of type 0/0A/1/2/3. The wireless device monitors the common search space for DCI format 0-0/1-0 with associated RNTIs, and group common DCI such as DCI 2-x (e.g. 2-0, 2-1, etc.).

When wireless device 22 is configured with a primary cell and one or more SCells, and wireless device 22 may be configured with an sSCell where, in the sSCell, wireless device 22 may be configured such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., to monitor only USS for DCI scheduling the primary cell. In the sSCell, wireless device 22 can be configured such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., to monitor one or more of the following DCI scheduling the primary cell:

- only non-fallback DCI (0-1/1-1/0-2/1-2),
- only UL DCI
  - one or both of non-fallback and fallback DCI

In one or more embodiments, the DCI can contain a carrier indicator field (CIF) to indicate the cell for which the DCI is intended. The carrier indicator field can be included in non-fallback DCI only, fallback DCI or both.

In one or more embodiments, the carrier indicator field (CIF) may be omitted if there are other means for wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., to determine the cell for which a DCI is intended. For instance, omission of CIF may be performed when sSCell is a DL-only cell and wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., can be configured to monitor UL DCI formats 0-1 and/or 0-0 on the sSCell where those UL DCI formats are used for primary cell scheduling. In another example, omission of CIF may be performed by configuring wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., to monitor different search spaces for DCI formats 0-1 and/or 0-0 on the sSCells where different search spaces are used for primary cell scheduling and for sScell scheduling.

In the primary cell, wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., can be configured to monitor a common search space (CSS), and possibly a user equipment search space (USS) for scheduling the primary cell.

Some aspects of the overall framework for enhanced CCS, including some aspects of DCI handling and limits BDs/CCEs, are beyond the scope of the disclosure.

DCI Size Budget for Primary Cell Scheduled by Two Cells

The DCI size budget is typically applied per scheduled cell. However, when sSCell is configured, the DCI size budgets may be applied in one or more manners with low implementation complexity.

In some embodiments, the DCI size budget for the primary cell scheduled by two cells is same as the DCI size budget for the primary cell scheduled by single cell. More specifically, wireless device 22 may not be expected to handle a configuration that results in one or more of:

- the total number of different DCI sizes configured to monitor on the primary cell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the primary cell is no more than 4; and
- the total number of different DCI sizes with C-RNTI configured to monitor on the primary cell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the primary cell is no more than 3.

In some embodiments, the DCI size budget for the sScell scheduling the primary cell and sScell scheduling the sScell (i.e., scheduling itself) is same as the DCI size budget for the sScell scheduled by single cell. More specifically, wireless device 22 is not expected to handle a configuration that results in one or more of:

- the total number of different DCI sizes configured to monitor on the sSCell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the sScell is no more than 4; and
- the total number of different DCI sizes with C-RNTI configured to monitor on the sScell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the sSCell is no more than 3.

A DCI size matching procedure may be applied and zero-padding may be introduced to satisfy/meet the budgets.

Some additional embodiments for DCI handling are described below.

Moving Only One DCI Format to sSCell′ Section

In this case, wireless device 22, such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., is configured to monitor a non-fallback DCI format for the primary cell on one serving cell only, e.g., DCI format 1-1 (non-fallback DCI for DL) is configured to be monitored only on Pcell and DCI format 0-1 (or non-fallback DCI for UL) is configured to be monitored only on the sSCell.

The DCI format that is configured to be monitored in the sSCell can carry the carrier indicator field. The DCI format that is configured to be monitored in the primary cell may not carry the carrier indicator field, as illustrated in FIG. 11, where wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., monitors a total of 4 DCIs for the primary cell (3 DCIs on the primary cell and one DCI on the sSCell). If the DCI size budget for DCIs scheduling the primary cell (including the 0-1/0-2 containing CIF on the sSCell scheduling primary cell) is exceeded, then size matching is triggered/implemented (including any zero-padding of DCIs) until the DCI size budget is satisfied.

In certain embodiments, wireless device 22, such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., can monitor DL DCI scheduling primary cell only on the primary cell. Wireless device 22, such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., can monitor UL non-fallback DCI scheduling primary cell only on the sSCell. Wireless device 22, such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., can monitor fallback DCI for uplink scheduling on the primary cell. The carrier indicator field is included in only the UL non-fallback DCI scheduling the primary cell.

In certain embodiments, wireless device 2,2 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., can monitor only one of “DL non-fallback DCI scheduling primary cell” or “UL non-fallback DCI scheduling primary cell” on the sSCell, the DCI containing a carrier indicator field. On the primary cell, wireless device 22, such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., can monitor the other non-fallback DCI and fallback DCIs scheduling primary cell on the primary cell, wherein the DCIs on the primary cell do not include a carrier indicator field.

The DCI size budget for sSCell scheduling the sSCell (i.e., sSCell scheduling itself) may be counted/considered separately.

“Using the Same Size for a DCI Format for the Primary Cell when the DCI Format is Monitored on Both Cells”

Wireless device 22, such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., is configured to monitor a non-fallback DCI format scheduling the primary cell on both serving cells (primary cell and sSCell) where the DCI format includes the carrier indicator field in both serving cells, or the corresponding DCI format's size on the primary cell that is size-matched to that DCI format's size on the sSCell. On the sSCell, DCI size-matching may not be needed between DCIs scheduling primary cell and DCIs scheduling other cells.

When DCI format 1-1 (or DL non-fallback DCI) and DCI format 0-1 (or UL non-fallback DCI) are configured to be monitored such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., on the primary cell for scheduling the primary cell and are configured to be monitored on the sSCell for scheduling the primary cell, both DCI formats can carry the carrier indicator field in both cells. This scenario is illustrated in FIG. 12 where wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., monitors a total of 4 DCI sizes for the primary cell (4 DCIs on primary cell and two DCIs on sSCell, satisfying the budget of three DCI sizes with C-RNTI (e.g., due to size-matching that kicks in for DCIs scheduling primary cell and since the same size of non-fallback DCI 0-1/1-1 is used in the primary and sSCell). While the CIF is illustrated separately in FIG. 12, the CIF may be considered as a field within the DCI formats.

The DCI size budget for sSCell scheduling the sSCell (i.e., scheduling itself) may be counted separately.

“Separate DCI Size Budget Treating ‘sSCell Scheduling of Primary Cell’ as an Extra Virtual Cell”

The sSCell scheduling primary cell may be considered an extra virtual cell with its own DCI budget. This can be borrowed, e.g., when wireless device 22 is under-utilizing its carrier aggregation capability.

Thus, the DCI budget for the primary cell scheduling the primary cell, i.e., itself, is independent from the DCI budget for the sSCell scheduling primary cell. An example is illustrated in FIG. 13 where the DCI formats 1-1 (non-fallback DCI for DL) and DCI format 0-1 (or non-fallback DCI for UL) are configured to be monitored on sSCell and may carry the carrier indicator field in both cells. Further, as illustrated in FIG. 13, wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., monitors a total 6 DCI sizes for the primary cell (4 DCIs on primary cell and two DCIs on sSCell). For illustration, the CIF is shown separately but it is considered as a field within the DCI formats. The portions with hatchings indicate the enhanced elements that help make sSCell scheduling of the primary cell possible.

More specifically, wireless device 22 is not expected to handle a configuration that results in one or more of:

- the total number of different DCI sizes configured to monitor on the primary cell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the primary cell is no more than 8; and
- the total number of different DCI sizes with C-RNTI configured to monitor on the primary cell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the primary cell is no more than 6.

“Borrowing DCI Size from the sSCell Budget or Applying an Aggregate Budget Over Primary Cell and sSCell”

In this case, the DCI size budget (4 total sizes and 3 sizes with C-RNTI) is maintained on the primary cell, but on the sSCell the DCI sizes for scheduling sSCell and for scheduling primary cell are counted within the same budget. In some cases, the DCI size budget is reduced on the primary cell (3 total sizes and 2 sizes with C-RNTI) when sSCell is configured.

More specifically, wireless device 22 is not expected to handle a configuration that results in one or more of:

- the total number of different DCI sizes configured to monitor on the sSCell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the sSCell is no more than 4;
- the total number of different DCI sizes with C-RNTI configured to monitor on the sScell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the sSCell is no more than 3.

In addition, in some cases, wireless device 22 is not expected to handle a configuration that results in one or more of:

- the total number of different DCI sizes configured to monitor on the primary cell for scheduling of the primary cell is no more than 4;
- the total number of different DCI sizes with C-RNTI configured to monitor on the primary cell for scheduling of the primary cell is no more than 3.

In some other case, a larger DCI size budget is maintained together across the primary cell and sSCell.

More specifically, wireless device 22 is not expected to handle a configuration that results in one or more of:

- the total number of different DCI sizes configured to monitor on the sSCell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the sSCell and configured to monitor on the primary cell for scheduling of primary cell is no more than 4+4=8;
- the total number of different DCI sizes with C-RNTI configured to monitor on the sScell for scheduling of the primary cell and configured to monitor on the sSCell for scheduling of the sSCell and configured to monitor on the primary cell for scheduling of primary cell is no more than 3+3=6.

Additionally, there may be a per-scheduled cell or a per-scheduled and scheduling cell limitations, e.g., wireless device 22 is not expected to handle a configuration that results in one or more of:

- the total number of different DCI sizes configured to monitor for the primary cell for scheduling of the primary cell is no more than 4;
- the total number of different DCI sizes with C-RNTI configured to monitor on the primary cell for scheduling of the primary cell is no more than 3.

“Non-Uplink CA Case or when sSCell is DL-Only”

Wireless device 22 is configured with a primary cell, and the wireless device 22 is configured with an SCell that has no uplink (e.g., no PUSCH-Config, etc.). The SCell is also configured as an sSCell. Since there is no uplink for the sSCell, the corresponding UL DCI formats are unused. Wireless device 22 such as via one or more of processing circuitry 84, processor 86, radio interface 82, operation unit 34, etc., can be configured to monitor uplink DCI formats (e.g. 0-0 and/or 0-1 and/or 0-2) for scheduling primary cell on the sSCell.

In one or more embodiments, there is no carrier indicator field needed in the DCI formats on the sSCell scheduling the primary cell. In one or more embodiments, there is no carrier indicator field needed in the DCI formats monitored on the primary cell.

The uplink DCI format monitored on the sSCell may schedule the primary cell only. On the sSCell, a same search space can be reused to schedule downlink DCI format scheduling sSCell and uplink DCI format scheduling primary cell.

On the sSCell, a single DCI size budget and DCI size matching can be applied to the DCI format(s) scheduling sSCell (e.g., downlink DCI format scheduling sSCell) and DCI format(s) scheduling primary cell (e.g., uplink DCI format scheduling primary cell).

An example is illustrated in FIG. 14 where the blocks with hatchings illustrate the DCIs intended for the primary cell scheduling. The DCI format 0-1 on the sSCell may be used for scheduling the primary cell.

Default QCL Assumption for Enhanced CCS

In cases of enhanced CCS from sSCell to primary cell, when the PDCCH to PDSCH gap is less than a certain/predefined threshold, the default TCI state for that PDSCH can be given by one of the following:

- the TCI state of the SS set on the primary cell is linked to the SS on which the PDCCH is detected on the sSCell.
- the TCI state of a reference SS set/CORESET on the primary cell—the reference SS set can be the SS set with lowest or highest search space ID that is monitored in the slot overlapping the slot in which the PDCCH scheduling the PDSCH is received on the sSCell.

Therefore, one or more embodiments described herein advantageously allow an SCell (referred to as a special SCell or sSCell) to schedule PDSCH/PUSCH on a primary cell.

DCI handling for the primary cell scheduling when sSCell is configured, including one or more following aspects:

Example embodiments of moving a single DCI format to sSCell, as described herein such as in the “Moving only one DCI format to sSCell” section.

Example embodiments are described in the “Use same size for a DCI format for the primary cell when the DCI format is monitored on both cells” section where the same size for a DCI format for the primary cell is used when DCI format is monitored on both cells. Introducing CIF on both primary cell and sSCell for a given DCI format scheduling primary cell is also provided.

Example embodiments where sScell scheduling primary cell is treated as extra virtual carrier for which DCI budgets are applied separately are provided as described herein such as in the “Separate DCI size budget treating ‘sSCell scheduling of primary cell’ as an extra virtual cell” section.

Example embodiments where sScell scheduling primary cell shares the sSCell budget or applying an aggregate budget over primary cell and sSCell are provided as described herein such as in the “Borrowing DCI size from the sSCell budget or applying an aggregate budget over primary cell and sSCell” section.

Example embodiments for non-uplink CA case or when sSCell is DL-only including operation without introducing an explicit carrier indicator field as provided as described herein such as in the “Non-uplink CA case or when sSCell is DL-only” section.

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and/or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and/or functionality described herein may be performed by, and/or associated to, a corresponding module, which may be implemented in software and/or firmware and/or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the “C” programming language. The program code may execute 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. In the latter scenario, the remote computer may be connected to the user's computer through 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).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

Abbreviations that may be used in the preceding description include:

Abbreviation
Explanation

ACK
Acknowledgment

ACK/NACK
Acknowledgment/Not-acknowledgment

BD
Blind Decode

BWP
Bandwidth Part

CBG
Code Block Group

CCE
Control Channel Element

DAI
Downlink Assignment Indicator

DCI
Downlink Control Information

HARQ
Hybrid Automatic Repeat Request

MIMO
Multiple Input Multiple Output

NACK
Not-acknowledgment

PDCCH
Physical Downlink Control Channel

PDSCH
Physical Shared Data Channel

PMO
PDCCH Monitoring Occasion

PUCCH
Physical Uplink Control Channel

TB
Transport Block

UCI
Uplink Control Information

It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings.

EMBODIMENTS

Embodiment A1. A network node operating as a secondary cell and configured to communicate with a wireless device (WD) and a primary cell for the wireless device, the network node configured to, and/or comprising a radio interface and/or comprising processing circuitry configured to:

- schedule at least one of a physical shared channel and physical control channel on the primary cell for the wireless device; and
- optionally cause transmission of the scheduling.

Embodiment A2. The network node of Embodiment A1, wherein the scheduling of at least one of the physical shared channel and physical control channel on the primary cell is performed by a physical downlink control channel, PDCCH, on the secondary cell.

Embodiment A3. The network node of Embodiment A1, wherein a downlink control information, DCI, budget for the wireless device for both the primary cell and secondary cell corresponds to a total number of DCIs sizes that the wireless device is provided is shared among the primary cell and is the same as the DCI budget for one of the primary cell and secondary cell.

Embodiment B1. A method implemented in a network node that is operating as a secondary cell and that is configured to communicate with a wireless device (WD) and a primary cell for the wireless device, the method comprising:

- scheduling at least one of a physical shared channel and physical control channel on the primary cell for the wireless device; and
- optionally causing transmission of the scheduling.

Embodiment B2. The method of Embodiment B1, wherein the scheduling of at least one of the physical shared channel and physical control channel on the primary cell is performed by a physical downlink control channel, PDCCH, on the secondary cell.

Embodiment B3. The method of Embodiment B1, wherein a downlink control information, DCI, budget for the wireless device for both the primary cell and secondary cell corresponds to a total number of DCIs sizes that the wireless device is provided is shared among the primary cell and is the same as the DCI budget for one of the primary cell and secondary cell.

Embodiment C1. A wireless device configured to communicate with a primary cell and a secondary cell, the wireless device configured to, and/or comprising a radio interface and/or comprising processing circuitry configured to:

- receive scheduling from the secondary cell, the scheduling configured to schedule at least one of a physical shared channel and physical control channel on the primary cell for the wireless device; and
- optionally operate according to the received scheduling.

Embodiment C2. The wireless device of Embodiment C1, wherein the scheduling of at least one of the physical shared channel and physical control channel on the primary cell is received via a physical downlink control channel, PDCCH, on the secondary cell.

Embodiment C3. The wireless device of Embodiment C1, wherein a downlink control information, DCI, budget for the wireless device for both the primary cell and secondary cell corresponds to a total number of DCIs sizes that the wireless device is provided is shared among the primary cell and is the same as the DCI budget for one of the primary cell and secondary cell.

Embodiment D1. A method implemented by a wireless device that is configured to communicate with a primary cell and a secondary cell, the method comprising:

- receiving scheduling from the secondary cell, the scheduling configured to schedule at least one of a physical shared channel and physical control channel on the primary cell for the wireless device; and
- optionally operating according to the received scheduling.

Embodiment D2. The method of Embodiment D1, wherein the scheduling of at least one of the physical shared channel and physical control channel on the primary cell is received via a physical downlink control channel, PDCCH, on the secondary cell.

Embodiment D3. The method of Embodiment D1, wherein a downlink control information, DCI, budget for the wireless device for both the primary cell and secondary cell corresponds to a total number of DCIs sizes that the wireless device is provided is shared among the primary cell and is the same as the DCI budget for one of the primary cell and secondary cell.