FI20195875A1 - Joint link adaptation for downlink control channel and data channel for wireless networks - Google Patents

Abstract

According to an example embodiment, a method may include determining (310), by a base station, a payload size for a downlink control channel between the base station and a user device, a payload size for a downlink data channel between the base station and the user device, and a channel quality indication (CQI) indicating a link quality between the base station and the user device, wherein the payload of the downlink control channel provides scheduling information for the downlink data channel; and, jointly determining (320), by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel.

Description

JOINT LINK ADAPTATION FOR DOWNLINK CONTROL CHANNEL AND DATA CHANNEL FOR WIRELESS NETWORKS TECHNICAL FIELD

[0001] This description relates to wireless communications.

BACKGROUND

[0002] A communication system may be a facility that enables communication between two or more nodes or devices, such as fixed or mobile communication devices. Signals can be carried on wired or wireless carriers.

[0003] An example of a cellular communication system is an architecture that is being standardized by the 3" Generation Partnership Project (3GPP). A recent development in this field is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. E- UTRA (evolved UMTS Terrestrial Radio Access) is the air interface of 3GPP's Long Term Evolution (LTE) upgrade path for mobile networks. In LTE, base stations or access points (APs), which are referred to as enhanced Node AP (eNBs), provide wireless access within a coverage area or cell. In LTE, mobile devices, or mobile stations are referred to as user equipments (UE). LTE has included a number of improvements or developments. Aspects of LTE are also continuing to improve.

[0004] 5G New Radio (NR) development is part of a continued mobile broadband evolution process to meet the requirements of 5G, similar to earlier evolution of 3G & 4G o wireless networks. 5G is also targeted at the new emerging use cases in addition to > mobile broadband. A goal of 5G is to provide significant improvement in wireless O performance, which may include new levels of data rate, latency, reliability, and security. = 5G NR may also scale to efficiently connect the massive Internet of Things (IoT) and I may offer new types of mission-critical services. For example, ultra-reliable and low- so latency communications (URLLC) devices may require high reliability and very low >

NN latency.

SUMMARY

[0005] According to an example embodiment, a method may include determining, by a base station, a payload size for a downlink control channel between the base station and a user device, a payload size for a downlink data channel between the base station and the user device, and a channel quality indication (CQI) indicating a link quality between the base station and the user device, wherein the payload of the downlink control channel provides scheduling information for the downlink data channel; and jointly determining, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel.

[0006] According to an example embodiment, an apparatus may include means for determining, by a base station, a payload size for a downlink control channel between the base station and a user device, a payload size for a downlink data channel between the base station and the user device, and a channel quality indication (CQI) indicating a link quality between the base station and the user device, wherein the payload of the downlink control channel provides scheduling information for the downlink data channel; and means for jointly determining, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel.

[0007] According to an example embodiment, an apparatus may include: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: determine, by a base station, a payload size for O a downlink control channel between the base station and a user device, a payload size for N a downlink data channel between the base station and the user device, and a channel 2 quality indication (CQI) indicating a link quality between the base station and the user - device, wherein the payload of the downlink control channel provides scheduling E information for the downlink data channel; and jointly determine, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data O 2 > &

channel.

[0008] According to an example embodiment, a non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are configured to cause a computing system to perform a method of: determining, by a base station, a payload size for a downlink control channel between the base station and a user device, a payload size for a downlink data channel between the base station and the user device, and a channel quality indication (CQI) indicating a link quality between the base station and the user device, wherein the payload of the downlink control channel provides scheduling information for the downlink data channel; and jointly determining, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel.

[0009] According to an example embodiment, a method may include: determining, by the base station, a transmission type of a data transmission for a downlink data channel between the base station and a user device, as a retransmission of data; determining, by the base station based on a presence or absence of feedback from the user device with respect to an initial or first transmission of the data, at least one of the following: a cause for the retransmission of the data via the downlink data channel, or whether or not a Hybrid ARQ (HARQ) combining is available to the user device based on the retransmission of the data via the downlink data channel; and jointly determining, by the base station, a link adaptation setting for both of the downlink data channel and a downlink control channel based at least on the transmission type being a retransmission, and based on at least one of the cause for the retransmission or whether or not a Hybrid ARQ (HARQ) combining may be performed at the user device based on the O retransmission of data, wherein a payload of the downlink control channel provides N scheduling information for the downlink data channel.

2 [0010] According to an example embodiment, an apparatus may include means —- for determining, by the base station, a transmission type of a data transmission for a E downlink data channel between the base station and a user device, as a retransmission of data; means for determining, by the base station based on a presence or absence of O 3 > &

feedback from the user device with respect to an initial or first transmission of the data, at least one of the following: a cause for the retransmission of the data via the downlink data channel, or whether or not a Hybrid ARQ (HARQ) combining is available to the user device based on the retransmission of the data via the downlink data channel; and means for jointly determining, by the base station, a link adaptation setting for both of the downlink data channel and a downlink control channel based at least on the transmission type being a retransmission, and based on at least one of the cause for the retransmission or whether or not a Hybrid ARQ (HARQ) combining may be performed at the user device based on the retransmission of data, wherein a payload of the downlink control channel provides scheduling information for the downlink data channel.

[0011] According to an example embodiment, an apparatus may include: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: determine, by the base station, a transmission type of a data transmission for a downlink data channel between the base station and a user device, as a retransmission of data; determine, by the base station based on a presence or absence of feedback from the user device with respect to an initial or first transmission of the data, at least one of the following: a cause for the retransmission of the data via the downlink data channel, or whether or not a Hybrid ARQ (HARQ) combining is available to the user device based on the retransmission of the data via the downlink data channel; and jointly determine, by the base station, a link adaptation setting for both of the downlink data channel and a downlink control channel based at least on the transmission type being a retransmission, and based on at least one of the O cause for the retransmission or whether or not a Hybrid ARO (HARO) combining may be N performed at the user device based on the retransmission of data, wherein a payload of 2 the downlink control channel provides scheduling information for the downlink data - channel.

E [0012] According to an example embodiment, a non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least O 4 > &

one processor, are configured to cause a computing system to perform a method of: determining, by the base station, a transmission type of a data transmission for a downlink data channel between the base station and a user device, as a retransmission of data; determining, by the base station based on a presence or absence of feedback from the user device with respect to an initial or first transmission of the data, at least one of the following: a cause for the retransmission of the data via the downlink data channel, or whether or not a Hybrid ARO (HARO) combining is available to the user device based on the retransmission of the data via the downlink data channel; and jointly determining, by the base station, a link adaptation setting for both of the downlink data channel and a downlink control channel based at least on the transmission type being a retransmission, and based on at least one of the cause for the retransmission or whether or not a Hybrid ARO (HARO) combining may be performed at the user device based on the retransmission of data, wherein a payload of the downlink control channel provides scheduling information for the downlink data channel.

[0013] The details of one or more examples of embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 isa block diagram of a wireless network according to an example embodiment.

[0015] FIG. 2 is a diagram illustrating joint link adaptation lookup tables according to an example embodiment.

o [0016] FIG. 3 is a flow chart illustrating operation of a base station according to 2 an example embodiment.

2 [0017] FIG. 4 is a flow chart illustrating operation of a base station according to T another example embodiment.

E [0018] FIG. 5 isa block diagram of a wireless station (e.g., AP, BS, RAN node, LO UE or user device, or other network node) according to an example embodiment.

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DETAILED DESCRIPTION

[0019] FIG. 1 isa block diagram of a wireless network 130 according to an example embodiment. In the wireless network 130 of FIG. 1, user devices 131, 132, 133 and 135, which may also be referred to as mobile stations (MSs) or user equipment (UEs), may be connected (and in communication) with a base station (BS) 134, which may also be referred to as an access point (AP), an enhanced Node B (eNB), a BS, next generation Node B (gNB), a next generation enhanced Node B (ng-eNB), or a network node. The terms user device and user equipment (UE) may be used interchangeably. A BS may also include or may be referred to as a RAN (radio access network) node, and may include a portion of a BS or a portion of a RAN node, such as (e.g., such as a centralized unit (CU) and/or a distributed unit (DU) in the case of a split BS). At least part of the functionalities of a BS (e.g., access point (AP), base station (BS) or (e)Node B (eNB), BS, RAN node) may also be carried out by any node, server or host which may be operably coupled to a transceiver, such as a remote radio head. BS (or AP) 134 provides wireless coverage within a cell 136, including to user devices (or UEs) 131, 132, 133 and

135. Although only four user devices (or UEs) are shown as being connected or attached to BS 134, any number of user devices may be provided. BS 134 is also connected to a core network 150 via a S1 interface or NG interface 151. This is merely one simple example of a wireless network, and others may be used.

[0020] A base station (e.g., such as BS 134) is an example of a radio access network (RAN) node within a wireless network. A BS (or a RAN node) may be or may include (or may alternatively be referred to as), e.g., an access point (AP), a gNB, an eNB, or portion thereof (such as a centralized unit (CU) and/or a distributed unit (DU) in O the case of a split BS or split gNB), or other network node.

N [0021] According to an illustrative example, a BS node (e.g., BS, eNB, gNB, 2 CU/DU, ...) or a radio access network (RAN) may be part of a mobile - telecommunication system. A RAN (radio access network) may include one or more BSs E or RAN nodes that implement a radio access technology, e.g., to allow one or more UEs to have access to a network or core network. Thus, for example, the RAN (RAN nodes, © 6 >

NN such as BSs or gNBs) may reside between one or more user devices or UEs and a core network. According to an example embodiment, each RAN node (e.g., BS, eNB, gNB, CU/DU, ...) or BS may provide one or more wireless communication services for one or more UEs or user devices, e.g., to allow the UEs to have wireless access to a network, via the RAN node. Each RAN node or BS may perform or provide wireless communication services, e.g., such as allowing UEs or user devices to establish a wireless connection to the RAN node, and sending data to and/or receiving data from one or more of the UEs. For example, after establishing a connection to a UE, a RAN node (e.g., BS, eNB, gNB, CU/DU, ...) may forward data to the UE that is received from a network or the core network, and/or forward data received from the UE to the network or core network. RAN nodes (e.g., BS, eNB, gNB, CU/DU, ...) may perform a wide variety of other wireless functions or services, e.g., such as broadcasting control information (e.g., such as system information) to UEs, paging UEs when there is data to be delivered to the UE, assisting in handover of a UE between cells, scheduling of resources for uplink data transmission from the UE(s) and downlink data transmission to UE(s), sending control information to configure one or more UEs, and the like. These are a few examples of one or more functions that a RAN node or BS may perform. A base station may also be DU (Distributed Unit) part of IAB (Integrated Access and Backhaul) node (a k.a. a relay node). DU facilitates the access link connection(s) for an IAB node.

[0022] A user device (user terminal, user equipment (UE), mobile terminal, handheld wireless device, etc.) may refer to a portable computing device that includes wireless mobile communication devices operating either with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: O a mobile station (MS), a mobile phone, a cell phone, a smartphone, a personal digital N assistant (PDA), a handset, a device using a wireless modem (alarm or measurement 2 device, etc.), a laptop and/or touch screen computer, a tablet, a phablet, a game console, a —- notebook, a vehicle, a sensor, and a multimedia device, as examples, or any other E wireless device. It should be appreciated that a user device may also be (or may include) a nearly exclusive uplink only device, of which an example is a camera or video camera O 7 > &

loading images or video clips to a network. A user device may be also MT (Mobile Termination) part of IAB (Integrated Access and Backhaul) node (a.k.a. a relay node). MT facilitates the backhaul connection for an IAB node.

[0023] In LTE (as an illustrative example), core network 150 may be referred to as Evolved Packet Core (EPC), which may include a mobility management entity (MME) which may handle or assist with mobility/handover of user devices between BSs, one or more gateways that may forward data and control signals between the BSs and packet data networks or the Internet, and other control functions or blocks. Other types of wireless networks, such as 5G (which may be referred to as New Radio (NR)) may also include a core network.

[0024] In addition, by way of illustrative example, the various example embodiments or technigues described herein may be applied to various types of user devices or data service types, or may apply to user devices that may have multiple applications running thereon that may be of different data service types. New Radio (5G) development may support a number of different applications or a number of different data service types, such as for example: machine type communications (MTC), enhanced machine type communication (eMTC), Internet of Things (IoT), and/or narrowband IoT user devices, enhanced mobile broadband (eMBB), and ultra-reliable and low-latency communications (URLLC). Many of these new 5G (NR) — related applications may reguire generally higher performance than previous wireless networks.

[0025] IoT may refer to an ever-growing group of objects that may have Internet or network connectivity, so that these objects may send information to and receive information from other network devices. For example, many sensor type applications or O devices may monitor a physical condition or a status, and may send a report to a server or N other network device, e.g., when an event occurs. Machine Type Communications 2 (MTC, or Machine to Machine communications) may, for example, be characterized by —- fully automatic data generation, exchange, processing and actuation among intelligent E machines, with or without intervention of humans. Enhanced mobile broadband (eMBB) may support much higher data rates than currently available in LTE.

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N

[0026] Ultra-reliable and low-latency communications (URLLC) is a new data service type, or new usage scenario, which may be supported for New Radio (5G) systems. This enables emerging new applications and services, such as industrial automations, autonomous driving, vehicular safety, e-health services, and so on. 3GPP targets in providing connectivity with reliability corresponding to block error rate (BLER) of 10* and up to 1 ms U-Plane (user/data plane) latency, by way of illustrative example. Thus, for example, URLLC user devices/UEs may require a significantly lower block error rate (BLER) than other types of user devices/UEs as well as low latency (with or without requirement for simultaneous high reliability). Thus, for example, a URLLC UE (or URLLC application on a UE) may require much shorter latency, as compared to a eMBB UE (or an eMBB application running on a UE).

[0027] The various example embodiments may be applied to a wide variety of wireless technologies or wireless networks, such as LTE, LTE-A, 5G (New Radio (NR)), cmWave, and/or mmWave band networks, IoT, MTC, eMTC, eMBB, URLLC, etc., or any other wireless network or wireless technology. These example networks, technologies or data service types are provided only as illustrative examples.

[0028] According to an example embodiment, downlink control signalling may be transmitted by a BS to one or more UEs via one or more downlink control channels, e.g., such as via one or more physical downlink control channels (PDCCHs). A payload of a PDCCH includes downlink control information (DCI), which includes scheduling information to schedule data transmissions (and possibly other information), such as an uplink resource allocation(s) and/or a downlink resource allocation(s) for a UE. For example, the downlink control information (DCI) provided within the PDCCH may O include scheduling information (e.g., including downlink resource allocation indicating N resources allocated for one or more UEs) for a downlink data transmission from the BS to 2 the UE via a data channel, such as via a physical downlink shared data channel (PDSCH). - [0029] A scrambled CRC (cyclic redundancy check) may be attached to the DCI E payload, to allow the UE to detect transmission errors, and to check that the DCI has been received by the correct UE (e.g., based on scrambled CRC). For example, within a © 9 >

N

PDCCH (downlink control channel), the cyclic redundancy check (CRC), calculated over the DCI payload, may be scrambled based on the identity of the UE to which the DCI is assigned or directed to, and then attached to the DCI payload. For example, a CRC may be scrambled based on the C-RNTI (cell radio network temporary identifier, or other identifier) to identify the UE that is supposed to receive the DCI. For example, upon receipt of the PDCCH at a receiving UE, the PDCCH may be decoded, and a CRC may calculated on the DCI payload and scrambled using the same procedure, based on the identity (e.g., C-RNTT) of the receiving UE. If the CRC checks (e.g, if the calculated scrambled CRC of receiving UE matches the scrambled CRC attached to DCI), then the DCI is declared by the receiving UE to be correctly received by the UE (as having been assigned to or intended for the receiving UE).

[0030] According to an example embodiment, a PDCCH may be transmitted using, e.g., 1, 2, 4, 8 or 16 contiguous control-channel elements (CCEs), where the number of CCEs may be referred to as the aggregation level (or CCE aggregation level). According to an example embodiment, a CCE may be a resource building block of a PDCCH, where a CCE may be, for example, a smallest set of resources that can be used for aPDCCH. For example, a CCE may be a unit upon which search spaces for blind decoding may be defined. Thus, each PDCCH may include one or more CCEs, depending on the aggregation level. According to an example embodiment, a CCE may include 6 resource element groups (REGs), each of which may include one resource block in an OFDM symbol. Thus, an aggregation level may indicate (or be associated with) an amount (e.g., or number or size) of resources used for a transmission of information via a channel.

O [0031] A search space may include a set of candidate PDCCHs (candidate & downlink control channels) formed by CCEs at given aggregation level(s), which the UE 2 is supposed to attempt to decode. A UE may have multiple search spaces for different - purposes (such as different common search spaces, and user-specific search spaces).

E [0032] At a configured PDCCH monitoring occasion (e.g., time(s) or locations LO within a slot where a PDCCH may be transmitted) for a search space, UEs will attempt to 3 10 >

N decode the candidate PDCCHs for that search space, for one or more DCI formats. For example, up-to five (or other number) of aggregation levels (e.g., corresponding to 1, 2, 4, 8 or 16 CCEs) with a given number of PDCCH candidates for each aggregation level can be configured for a certain search space. For example, transmitting control information (e.g., scheduling information in the DCI of the PDCCH) via a higher CCE aggregation level may typically mean that such control information will be transmitted using a larger (or higher) amount of resources (e.g., and thus more reliably, but less efficiently) than transmitting control information via a lower (or smaller) aggregation level.

[0033] Thus, a search space configuration may be provided to or communicated to a UE, and may include, for example, information identifying one or more of: a control resource set (CORESET) indicating the time-frequency resources upon which a PDCCH(s) is transmitted; demodulation reference (DMRS) signals, which may be used by the UE for demodulation of data or control signals (e.g., DCI); an indication of PDCCH monitoring occasions, which may include times or locations within a slot(s) where a PDCCH(s) may be transmitted; DCI format(s) to be monitored; and/or, a number of PDCCHs (or PDCCH candidates) monitored for each aggregation level.

[0034] From the perspective of a UE, each PDCCH may be considered a PDCCH candidate because, for example, the PDCCH may or may not be present (may not have been transmitted, or may not have been received), may have a DCI format that may be the same or different than the DCI format that is being monitored by the UE, and/or may have a CRC that is scrambled with a UE identity that is the same as, or different from, the receiving UE.

O [0035] As an illustrative example, PDCCH monitoring may include, for example, N demodulating a received signal, decoding the demodulated PDCCH or DCI, e.g., to 2 detect that the DCI is (or is not) assigned to or intended for the receiving UE. Thus, — decoding of Downlink Control Information (DCI) may use blind decoding where the UE E may perform a number of decoding attempts on a number of Physical Downlink Control Channel (PDCCH) candidates for a number of defined DCI formats that are being LO 11

N monitored by the UE. Monitoring may also include performing a CRC check on the decoded PDCCH. To receive a DCI on a PDCCH, a UE monitors a set of PDCCH candidates in one or more configured monitoring occasions (times within one or more slots where PDCCH will be transmitted) according to the search space set configurations. A UE may monitor multiple PDCCH candidates, based on one or more DCI formats, and/or based on its UE identity, for example.

[0036] If the DCI, intended for the UE, provides a downlink resource allocation (for a downlink data transmission on a data channel), the UE may then attempt to decode and receive the data on the data (e.g., PDSCH) channel, based on the resources identified in the downlink resource allocation of the received DCL

[0037] In many cases, wireless communication systems may suffer from one or more impairments that may limit or impair a link quality or channel quality, such as the signal-to-interference-plus-noise ratio (SINR). Some example impairments may include, e.g., channel fading, path loss, interference from other users, and receiver noise. Consequently, data packets sent from one network node to another network node may not be reliably received at another point or network node. In some cases, each data packet may be decoded only with a certain probability, e.g., depending on the instantaneous SINR and the utilized link parameters (e.g., transmit power, coding rate,...). Hence, many services may demand re-transmissions of corrupted packets to increase reliability at the price of the increased latency introduced by the re-transmission scheme. Depending on the radio technology, certain procedures may be available for that purpose, e.g, Hybrid Automatic Repeat Request (HARQ) combining (also referred to as soft combining) may be used, such as Chase Combining or Incremental Redundancy (IR), in O order to increase a likelihood that the receiver will successfully decode/receive data. For N example, an incorrectly received (e.g., not successfully decoded) coded data blocks are 2 often stored at the receiver rather than discarded, and when the re-transmitted block is —- received, the two blocks may be combined to improve the likelihood the receive can E correctly receive (decode) the block of data. For example, in some cases, while it is possible that one or two given transmissions (e.g., a first or initial transmission of a data O 12 > &

block, and/or a retransmission of the data block) cannot be independently decoded by the receiver without error, it may happen that the combination of the previously erroneously received transmissions may provide the receiver with sufficient information to correctly decode the data block.

[0038] As noted, two example HARQ (or soft) combining methods (although other HARQ combining techniques may be used) may include: 1) Chase combining: e.g., where every re-transmission for a block contains the same information (data and parity bits). The receiver may use, for example, maximum-ratio combining to combine the received bits with the same bits from a previous transmission(s). Because, for example, all transmissions for the block are identical, Chase combining can be seen as additional repetition coding. In this manner, for Chase combining, every re-transmission may add extra energy to the received transmission through an increased signal to noise ratio; and, 2) Incremental Redundancy (IR): e.g., where every re-transmission may contain different information than the previous transmission/retransmission. Multiple sets of coded bits may be generated, each representing the same set of information bits. The re-transmission may typically use a different set of coded bits than the previous transmission, with different redundancy versions generated by puncturing the encoder output. Thus, at every re-transmission, the receiver may obtain additional information that may be used to decode or receive the data. According to an example implementation, one or more retransmission modes may be used to retransmit data, including at least the following for example.

[0039] According to an example NACK-based retransmission mode, a Hybrid Automatic Repeat Reguest (HARO) scheme may be used to trigger a fast retransmission O on the lower layers of the protocol stack. The basic idea is that the receiving node sends N back to the transmitting node an indication of successful (ACK) or unsuccessful (NACK) 2 decoding of the data packet. In case of a NACK, the transmitting node performs a —- retransmission, e.g., transmits a second representation (e.g., a copy or a redundancy E version) of the failed data packet. This can be a repetition of the packet in order to allow HARO (e.g., soft) combining of both attempts at the receiving node, or, more advanced, O 13 > &

additional redundancy (or redundancy version) that lowers the code rate, and consequently improves the probability for successful decoding of the extended packet (first transmission plus additional redundancy of the second transmission). The main advantage of the NACK-based retransmission mode is that re-transmissions occur only if necessary (e.g., only in response to a NACK, or other explicit request for retransmission, for example. According to an example embodiment, for downlink data transmissions, the transmitting node (BS) may assume that HARQ combining may be available to the UE (receiving node) based on an initial transmission and a retransmission of the data, if a NACK was received by the BS for the initial transmission.

[0040] Therefore, a receiving node (e.g., UE) may send HARO feedback to the transmitting node, e.g., including either an acknowledgement (ACK) that the data was received and decoded, or a negative acknowledgement (NACK) that indicates that the data was not decoded. For example, in some cases, a UE that is able to receive and decode the DCI, obtain scheduling information, and then receive and decode the downlink data directed to the UE via the PDS

[0041] Also, according to an example embodiment, a UE may measure one or more signal parameters (e.g., link quality) of reference signals received from a BS, and may send a channel state information (CSI) report to the BS. The CSI report, may include, for example, one or more of: - A Rank Indicator (RI), which is a suitable number of transmission layers for a downlink (DL) transmission; - A Precoder Matrix Indicator (PMI), which may indicate what a device (e.g., UE) estimates as a suitable precoder matrix based on the selected rank; and O - A Channel Quality Indication (or channel quality indicator) (CQI), which may N express or indicate the BS-UE channel or link guality, as measured by the UE. 2 The CQI may indicate what the UE estimates as a suitable channel coding rate —- and modulation scheme based on the selected precoder matrix. E [0042] According to an example embodiment, link adaptation may include adjusting or adapting one or more settings or parameters based on the conditions of the O 14 >

N radio link (e.g., based on the pathloss, the interference due to signals from other transmitters, the available power margin, etc.).

[0043] According to an example embodiment, successful data communication in DL is conditioned upon the reliable transmission of control information (which may also be referred to as metadata). Aiming to maximize the supported throughput for eMBB services, large data packets are usually scheduled with higher modulation and coding schemes (MCSs). This results in a medium block error rate (BLER) (around 10%) of the initial transmission. The possible errors are then recovered by HARQ/ARQ procedures. Hence, network performance and transmission reliability mainly depend on how the data packets are scheduled. However, the same cannot necessarily be applied to most URLLC use cases where control information (metadata) size may, at least in some cases, be comparable to the data packet size and the data BLER target is set to small (smaller BLER targets than eMBB, for example) values. Also, in URLLC, at least in some cases, the metadata overhead, the corresponding error probability, and erroneous decoding of feedback signals may impact performance, e.g., for URLLC or similar use cases.

[0044] According to an example embodiment, a low-error transmission of control information (e.g., DCI via PDCCH) or metadata may be useful (and in some cases important) to efficiently support URLLC.

[0045] A typical approach used today for link adaptation may involve separately (or independently) performing link adaptation only for one channel, or performing link adaptation separately for each of a data (e.g., PDSCH) channel and an associated control (e.g., PDCCH) channel. For example, one approach may involve separately allocating the control information (or separately allocating resources for the transmission of control O information/DCT) at the beginning of the DL sub-frame, and then later allocating N resources for transmission of associated data, e.g., based on a separate link adaptation for 2 the data channel. While separately performing link adaptation for a DL control channel —- and a DL data channel may benefit from a low (or a lower) computational complexity, E performing separate link adaptations for these two channels may not satisfy OoS requirements or result in unnecessary use of additional resources.

O 15 >

N

[0046] According to an example embodiment, joint link adaptation may be performed for a control channel and a data channel, e.g., in order to reduce (and in some cases possibly minimize) the amount of resources allocated for these channels, while still meeting or satisfying quality of service (QoS) requirements for these channels. Therefore, according to an example embodiment, example techniques are provided that may include, for example, jointly performing link adaptation for both a data channel (e.g, PDSCH channel) and a control channel (e.g., PDCCH channel). For example, a BS may determine a payload size for a downlink control (e.g., PDCCH) channel between the BS and a UE, a payload size for a downlink data (e.g., PDSCH) channel between the BS and the UE, and a channel quality indication (CQI) indicating a link quality between the BS and the UE. For example, the payload (e.g., DCI) of the downlink control (e.g., PDCCH) channel provides scheduling information for the downlink data (e.g., PDSCH) channel. The BS may then jointly determine a link adaptation setting for both of the downlink control (e.g., PDCCH) channel and the downlink data (e.g., PDSCH) channel.

[0047] As noted, joint link adaptation (or jointly performing link adaptation) may be performed for a control channel and a data channel, e.g., in order to reduce (and in some cases possibly minimize) the amount of resources allocated for these channels, while still meeting or satisfying quality of service (QoS) requirements for these channels, e.g., subject to the outage (reliability) constraint, given the payload sizes of those channels, and also the uplink control channel error probabilities. Jointly performing link adaptation for a DL control channel and a DL data channel, and/or jointly determining a link adaptation setting for both the DL control channel and the DL data channel may include performing one or more calculations or estimates, in order to determine the link O adaptation settings for both channels, based on at least one parameter associated each of N the two channels. Thus, for example, the jointly determining a link adaptation setting for 2 both the DL control channel and the DL data channel may be based on at least a first - parameter associated with the DL control channel and at least a second parameter E associated with the DL data channel. According to an example embodiment, rather than separately performing link adaptation for these two channels, the link adaptation LO 16

N setting(s) for each of two channels may be determined based on at least some information provided with respect to each of these channels, and/or the link adaptation setting(s) for the two channels may be determined via one or more calculations that may take into account (or may be based upon) information with respect to both (or each) of the two channels. Thus, rather than providing separate or independent link adaptation setting, jointly performing link adaptation (or jointly determining a link adaptation setting) for the two channels may include performing link adaptation together for these two channels (e.g., based on a set of one or more calculations that may consider or may be based on one or more parameters with respect to both of the channels, or based on one or more parameters for each of the channels). Some example parameters for (or with respect to) the data channel and/or control channel may include, e.g., payload size for the data channel, payload size (e.g., DCI size) of the control channel, a reliability and latency target, COL, etc.

[0048] According to an example embodiment, the link adaptation setting for both of the downlink control channel and the downlink data channel may include, e.g.: an aggregation level or a control channel element (CCE) aggregation level (e.g., or an amount of resources allocated) for the downlink control channel; or a modulation and coding scheme (MCS) to be used for a downlink data transmission via the downlink data channel. These are some examples, and other link adaptation settings may be jointly determined as well. For example, the MCS may include or indicate a modulation rate (or modulation order), where a lower modulation rate (modulation order) may provide higher reliability but lower spectral efficiency, as compared to a higher modulation rate (which may provide higher spectral efficiency, but at a cost of lower reliability). The MCS may O include or indicate a coding rate (e.g., Forward Error Correction (FEC) code rate). Thus, N in an example embodiment, the BS may perform joint link adaptation for a data channel 2 and a control channel, e.g., which may include jointly determining at least a first link —- adaptation setting (e.g., an aggregation level, or an amount of resources allocated) for a E DL control (e.g., PDCCH or DCT) channel, and a second link adaptation setting (e.g., a MCS) for a DL data (e.g., PDSCH) channel. Other link adaptation settings may be © 17 >

N jointly determined for a DL data channel and a DL control channel.

[0049] According to an example embodiment, the method or technique may further include allocating, by the BS based on the link adaptation setting for both of the downlink control channel and the downlink data channel (e.g., based on the aggregation level for the control channel and the MCS for the data channel, or other setting), resources for transmission of control information via the downlink control channel and resources for transmission of data via the downlink data channel.

[0050] Also, according to an example embodiment, the joint link adaptation performed for the data channel and the control channel may be impacted or based upon a transmission type (e.g., initial or first transmission, or a retransmission), e.g., since one or more different parameters may be applicable for the two transmission types (e.g., a different reliability targets may be applied for a first or initial transmission and a retransmission, for a channel). For example, a higher reliability target may be applied in the case of a retransmission, e.g., since for URLLC only one retransmission may be allowed, depending on the permitted maximum latency. Thus, for example, different link adaptation setting(s) may be obtained or determined, e.g., for different transmission types. For example, at least in some cases, a lower MCS and/or a higher aggregation level may be determined via joint link adaptation for a retransmission (e.g., to provide increased reliability), as compared to a first or initial transmission (e.g., which may use a higher MCS and/or a lower aggregation level). Thus, for example, different transmission types may result in (or cause) the BS to determine (e.g.., jointly determine) a different link adaptation setting(s) for both the data channel and the control channel.

[0051] Furthermore, according to an example embodiment, a cause of a O retransmission by a BS and/or whether HARO combining is available at a UE for the N retransmission, may impact or change the link adaptation settings determined via joint 2 link adaptation. For example, for a case in which a retransmission by the BS is caused —- (or triggered) by the BS receiving a NACK associated with a first or initial transmission, E this means that the UE received (but was unable to decode) the first or initial transmission, and HARO combining is available at the UE for the retransmission (e.g, O 18 >

N combining the first transmission and the retransmission, to improve probability of decoding the data). On the other hand, if a retransmission is caused for some other reason, such as a discontinuous transmission, e.g., a retransmission from the BS based on a timer at the BS expiring without an ACK or NACK being received, or caused by a blind retransmission by the BS (e.g., BS retransmitting the data a threshold number of times, or until an ACK is received), or then this means the UE may not have received the first or initial transmission. In such a case of discontinuous transmission, the HARQ combining may not be available (not expected to be available) to the UE, and no HARQ combining gain can be assumed by the BS. Thus, in the case where HARQ (or soft) combining is available to the UE for a retransmission, this means that a different link adaptation setting may be determined or may be used (e.g., a higher MCS, and/or lower aggregation level may be used) to obtain the same reliability target, whereas a lower MCS and/or a higher aggregation level may be determined or may need to be used to obtain the same or similar reliability target where no HARQ combining gain is available to the UE. Thus, for example, a different cause or trigger of a retransmission (and/or whether or not HARQ combining is available to the UE for the retransmission) may result in (or cause) the BS to determine (e.g.., jointly determine) a different link adaptation setting(s) for both the data channel and the control channel.

[0052] Thus, according to an example embodiment, the link adaptation, and/or jointly determining a link adaptation setting for both the DL control channel and the DL data channel may be based on the transmission type, and may also be based on a cause of a retransmission and/or whether or not HARQ (or soft) combining is available to the UE for the retransmission if the transmission type is retransmission.

O [0053] Therefore, according to an example embodiment, a method or technigue N may include determining, by the BS, a transmission type of a data transmission for the 2 downlink data channel, as either a first transmission of data or a retransmission of the - data, and a cause for retransmission if the transmission type is retransmission; wherein E the jointly determining a link adaptation setting comprises jointly determining a link adaptation setting for both of the downlink control channel and the downlink data LO 19

O channel based at least on the transmission type for a data transmission via the downlink data channel, and based on the cause for retransmission if the transmission type is retransmission.

[0054] According to an example embodiment, in the case where the transmission type is a retransmission, the following technique or method may be performed: Determining, by the BS, a transmission type of a data transmission for the downlink data channel, as a retransmission; determining, by the BS based on a presence or absence of feedback (e.g., based on the BS detecting a HARQ NACK, or not) from the UE with respect to a first or initial transmission of the data, at least one of: a cause for the retransmission of data via the downlink data channel, or whether or not a Hybrid ARQ (HARQ) combining may be performed at UE based on the retransmission of data via the downlink data channel; wherein the jointly determining a link adaptation setting comprises jointly determining, by the BS, a link adaptation setting for both of the downlink control channel and the downlink data channel based at least on the transmission type for a data transmission via the downlink data channel being a retransmission, and based on at least one of the cause for the retransmission (e.g., retransmission based on receiving a NACK, or based on a discontinuous transmission where a NACK was not received) or whether or not a Hybrid ARQ (HARQ) combining may be performed at the UE based on the retransmission of data.

[0055] According to an example embodiment, the cause for retransmission may include determining at least one of the following as the cause for the retransmission of data via the downlink data channel: a negative acknowledgement (NACK) is received by the BS from the UE for a first or initial transmission of the data; or a discontinuous O transmission is detected by the BS for the first or initial transmission of the data, in which N neither an acknowledgement (ACK) nor a negative acknowledgement (NACK) is 2 received by the BS for the first or initial transmission of the data. Further details and —- illustrative examples will now be provided.

E [0056] According to an example embodiment, joint link adaptation for the PDCCH and PDSCH may be a challenging problem. For a UE to successfully receive a O 20 >

N dynamic scheduled data transmission, it must successfully decode the PDCCH carrying the scheduling grant, as well as successfully decode the corresponding PDSCH transmission that carries the actual data payload. If (for some reason) the UE does not successfully decode a data transmission, the gNB will schedule a HARQ retransmission. That is, a new scheduling grant (PDCCH) and the data payload (PDSCH). Notice here that HARQ soft combining (Chase Combining or Incremental Redundancy) is supported for the PDSCH, while PDCCH transmissions do not support HARQ combining. In order to facilitate efficient link adaptation for the PDCCH and PDSCH, the gNB relies mainly on the CQI feedback from the UE (which may express or indicate the channel quality at the UE) and the related QoS (quality of service) requirements for the transmission. Thus, for example, the gNB may perform the link adaptation for PDCCH and PDSCH to fulfill the UE’s QoS requirements, while using as few resources as possible, taking into account the UE’s channel quality or link quality conditions. For eMBB type of services, this translates to conducting link adaptation to maximize the average experienced throughput. For URLLC type of services with strict latency bounds of, e.g., 1 ms, that may result in the BS conducting link adaptation so that the URLLC (data) payload is safely transmitted to the UE within the latency bound (e.g., allowing for only one HARO retransmission for NR (new radio)/5G if the latency target is e.g., 1 ms, while using a TTI (transmission time interval) size of 2-symbol mini-slot at 30 kHz subcarrier spacing).

[0057] Thus, according to an example embodiment, techniques or methods are provided, e.g., for joint PDSCH and PDCCH link adaptation to reduce (e.g., minimize) the number of allocated resources while satisfying the UE or application (e.g., URLLC) quality of service (QoS) requirements. The example methods or techniques described O herein may offer benefits (e.g., resource or spectral efficiency) over existing approaches N for link adaptation.

2 [0058] In some existing approaches to link adaptation for PDCCH and PDSCH, - the link adaptation for those two physical channels is conducted independently, aiming E for a fixed parameterized BLER target. That is, the aggregation level for the PDCCH is typically selected to reach a target BLER of approximately 1% at the UE, and the MCS LO 21

N selection for the PDSCH to achieve a target BLER of 10%. This is how link adaptation is typically conducted for (e)MBB type of services. For URLLC services (due to stricter latency requirements), typically, a BLER of 0.01-0.1% for the PDCCH and 0.1-1% for the PDSCH is assumed. Notice that for both the (e)MBB and URLLC use cases, the target BLER for the PDSCH is typically higher than that of the PDCCH. This is due to the HARQ support for PDSCH, thus allowing for the possibility of HARQ combining for the DL data channel (PDSCH) (not supported for the PDCCH).

[0059] There may be at least two possible outcomes of the initial transmission that may trigger a retransmission. 1) NACK triggered retransmission (UE failure to decode data); and 2) Discontinuous transmission (UE failure to decode control information; no ACK or NACK received for initial transmission). For example, these different causes for retransmission by the BS may cause the joint link adaptation performed by the BS to generate or output a different link adaptation setting for one or both of the channels (e.g., different retransmission causes may result in a different link adaptation setting(s) to be determined or output by the BS), e.g., because HARQ combining may be available to the UE for some retransmission causes, while HARQ combining may not be available to the UE for other retransmission causes.

[0060] 1) NACK triggered retransmission (UE failure to decode data): This case or situation may occur when the UE receives (and decodes) the control information but fails to decode the data. The UE will then send a NACK to the BS/gNB for this initial transmission. Correct decoding of the NACK attempted by BS will trigger scheduling of the corresponding HARQ retransmission. Otherwise, if the BS decodes the NACK as ACK and assumes successful transmission, it will result in termination of the O transmission procedure for this data. However, the packet could be still recovered by N automatic repeat reguest (ARO) protocol initiated by radio link control layer that imposes 2 excessive latency and 1s therefore considered as outage (or failed) for URLLC —- applications.

E [0061] 2) Discontinuous transmission (UE failure to decode control information; no NACK received for initial transmission): In this situation or case that may trigger LO 22

O retransmission is when the UE fails to decode the control information (e.g., PDCCH) or metadata. This is known as discontinuous transmission (DTX). In this scenario, the UE does not know if any transmitted data from the BS is directed to or intended for the UE, as it has not decoded the control information (e.g., DCI including scheduling information. intended to a transmission. Thus, in this case, the UE does not forward any HARQ feedback to the BS. The BS does not receive an ACK nor a NACK for this initial transmission. This leads to a HARQ timeout at the BS, which happens when the BS does not receive ACK/NACK signals via the UL feedback channel (e.g., via uplink control channel (PUCCH)) within a predefined time interval. This leads to a retransmission by the BS. For example, the timeout duration may be equal to an ACK/NACK feedback time, so that one retransmission can be performed within the maximum URLLC latency budget. Since the control information required to identify the data block in the initial transmission was not correctly decoded (unlike the previous case), there is no possibility of HARQ combining in this case.

[0062] According to an example embodiment, when there is a failure in decoding control information for the first or initial transmission (discontinuous transmission), the BS, or the BS based on or using a lookup table (for performing joint link adaptation) may provide or jointly determine a link adaptation setting(s) for the retransmission such that (one or) both data and control channels may be configured with a lower coding rate and/or lower modulation rate (more reliable), and/or the control channel may be configured with a higher (more reliable) aggregation level, e.g., to improve reliability of the retransmission. Or, more generally, in the case of discontinuous reception (no NACK received by BS for initial transmission), one or more link adaptation settings may be O determined by the BS to provide a more reliable, but less spectrally efficient N configuration (e.g., because HARO combining is not available at the UE for the 2 retransmission) for the retransmission. On the other hand, if the UE was unable to - decode the data (but was able to decode the control information), a NACK is typically E received by the BS from the UE, and one or more link adaptation settings may be jointly determined by the BS to provide, e.g., a less reliable, but more spectrally efficient, LO 23

N configuration (including link adaptation settings) for the retransmission (e.g., because HARO combining, providing a combining gain at the UE, is available at the UE for the retransmission), such as a higher modulation rate, a higher coding rate on one or both channels and/or a lower aggregation level for the control channel. In this manner, as an illustrative example, a more efficient resource utilization may be provided.

[0063] Thus, according to a first example embodiment, joint link adaptation may be performed (or a link adaptation setting may be determined by the BS for both the DL data channel and DL control channel), e.g., based on: the payload size for PDCCH (e.g., number of bits for the DCI); the payload size for the PDSCH (e.g., number of bits for transport block size including MAC header and CRC); A CQI, which may indicate a link quality or link condition at the UE, and may, for example indicate a signal to interference plus noise ratio (SINR) or other link quality at the UE. The link adaptation may be performed based on different, or additional parameters.

[0064] Thus, in an illustrative example embodiment, the BS may generate tables based on a plurality of dynamic input parameters (e.g., payload sizes for the DL data channel and DL control channel and the CQI or other indication of link quality at the UE), and where the tables may output either the desired BLER of the downlink control channel (e.g., PDCCH) and the DL data channel (e.g., PDSCH), or output a link adaptation setting for both of the DL control channel (e.g., aggregation level) and the DL data channel (e.g., MCS). The desired or target BLER for the two channels may be mapped to associated values of MCS and/or aggregation level (or other link adaptation setting).

[0065] In a second example embodiment, the link adaptation setting for both O channels may be determined based on the transmission type, as either an initial or first N transmission or a retransmission, and/or based on anticipated uplink probability of errors 2 in feedback channel (i.e., the BS/gNB’s ability to correctly decode ACK, NACK, and — DTX (discontinuous transmission) transmissions from the UE. In case of scheduling a E retransmission (for a transmission type of retransmission), the link adaptation setting may be determined by the BS based on a cause or trigger of the retransmission (and/or LO 24

O whether or not HARQ combining is available at the UE for the retransmission). For example, if the BS/gNB received a NACK associated with a previous transmission, this indicates to the BS that the UE correctly received (and decoded) the control information (e.g., DCI ) via the DL control channel (e.g., via PDCCH) for the first transmission, while failing to correctly decode the DL data channel (e.g., PDSCH), this indicates that HARQ combining is (or should be) available at the UE for the retransmission (e.g., because the UE has received the initial or first transmission, or previous transmission, and should be available at the UE for HARQ combining with the retransmission). If the retransmission is caused by a discontinuous transmission (DTX), e.g., where no ACK or NACK feedback was received by the BS from the UE for the first or initial transmission, then this informs the BS/gNB that neither the DL control channel (e.g., PDCCH) nor the DL data channel (e.g., PDSCH) were likely received by the UE for the initial or first transmission, and thus, HARQ combining is not likely available at the UE for any retransmission (thus, no HARQ combining gain available at the UE for this case). Of course, the use of HARQ combining gain may increase a probability of decoding data or a packet. Thus, according to an example embodiment, the BS, or table used by the BS for link adaptation, may determine or provide different link adaptation parameters (e.g., different aggregation levels and/or a different MCS) based on a different cause for the retransmission.

[0066] According to an example embodiment, DL transmission performance may be considered and improved, e.g., for an orthogonal frequency division multiple access (OFDMA) transmission in which a base station (BS) serves UEs with packets of D bytes. URLLC, for example, requires reliable transmission within a time budget in the order of O millisecond(s) and very low target outage probability (or reliability target). To reduce the N transmission time and achieve the extreme latency reguirement of one millisecond, a 5G 2 NR flexible numerology may be used with the capability of mini-slot scheduling.

—- Depending on the payload size and service requirements, the TTI varies between 1-14 E OFDM symbols and the sub-carrier spacing can be configured from 15 kHz up to 240 kHz, by way of illustrative example. Assuming a mini-slot length of two to four OFDM LO 25

NN symbols with 15-30 kHz sub-carrier spacing, for example, and by taking into account the packet transmission/processing time and the retransmission/HARQ delay, this leaves enough time budget for a single retransmission (if initial transmission fails).

[0067] Transmitting the D bytes of data requires preceding transmission of M bytes of control information or DCI (e.g., metadata) carrying transceiver/transmission specific information such as UE-ID (UE identifier), adopted MCS, precoding matrix information (PMI), allocated physical resource block for DL transmissions, etc. Since the amount of data to be transmitted is usually large in eMBB, the data packet size is set to be significantly larger than the control information or metadata (M >>D).

[0068] Having different KPIs in URLLC, the overhead and the loss-rate of control information (metadata) may not be insignificant, and may impact link adaptation. For example, low-error control information (metadata) transmission may be very useful to fulfil the reliability target. Hence, it is desirable to revise the link adaptation process to jointly consider both data allocation (resource allocation for transmission of data) and control information allocation (resource allocation for transmission of control information) as part of the link adaptation process.

[0069] Example embodiments or techniques are described for performing joint PDCCH and PDSCH link adaptation for a first transmission.

[0070] FIG. 2 is a diagram illustrating joint link adaptation lookup tables according to an example embodiment. Link adaptation tables may be generated or determined, e.g., by the BS or another network node, and then used by the BS to perform joint link adaptation or to jointly determine a link adaptation setting for both the DL control (e.g., PDCCH) channel and a DL data (e.g., PDSCH) channel. The tables 210 O include, for example, a joint link adaptation lookup table 212 for a first/initial N transmission, a joint link adaptation lookup table 214 for retransmission caused by 2 NACK reception, and a joint link adaptation lookup table 216 for retransmission caused - by discontinuous transmission (no NACK received). Example inputs to the table(s) may E include, e.g., control information size, data size, the COI from the UE, the transmission type (e.g., initial or first transmission or a retransmission) and a cause for retransmission O 26 >

N

(in the case of a retransmission). Outputs of these table(s) may include, e.g., target BLER of PDCCH (DL control channel), target BLER for PDSCH (DL data channel), and/or link adaptation settings for both the DL control channel and the DL data channel (e.g, aggregation level for the PDCCH and/or the MCS for the DL data channel. Also, for example, one or more of the link adaptation settings may be associated with, or may be set according to, a target BLER (or to achieve the target BLER). For example, the transmission type may be used to select either table 212 (for initial transmission) or tables 214 and 216 (for retransmission). Also, for a retransmission, a cause for a retransmission may be used to select either table 214 (retransmission caused by receipt of a NACK) or table 216 (retransmission caused by discontinuous transmission). A BS may receive the input(s), and then use the table(s) to perform joint link adaptation, e.g., to jointly determine a link adaptation setting for both a DL control channel and a DL data channel.

[0071] Hence, for each new data transmission, the BS/gNB may perform a look- up in the table 212, and, e.g., determines or selects the aggregation level and MCS for the PDCCH and PDSCH, respectively, to achieve the most resource efficient transmission, while still fulfilling the QoS requirements for the UE.

[0072] When the BS/gNB decides to schedule a retransmission, it may perform joint link adaptation, and, e.g., jointly determine a link adaptation setting(s) for both the PDCCH and the PDSCH. But the look-up table that is used may be different depending on the cause of the transmission as follows:

[0073] NACK received: the NACK received means that a data transmission was received by the UE, but was unable to decode it (and the UE sends a NACK to the BS), and the UE can then combine this first transmission with a second received transmission O (a retransmission) to provide HARO combining gain. The look-up table takes into N account that the HARO combining for the PDSCH will be present for the retransmission, 2 but also respecting that the residual error probability is much lower for the retransmission — (in case of URLLC) because no further retransmissions are allowed.

E [0074] Discontinuous Transmission: The BS had a transmission towards UF. The UE did not receive the DCI for this data transmission, and thus UE does not attempt to © 27 >

N decode this data from BS. No ACK or NACK sent by UE to BS. No HARQ combining gain is possible for retransmission, because UE did not receive first data transmission. The look-up table takes into account that the residual error probability is much lower (in case of URLLC) because no further retransmissions are allowed. And that no HARQ combining gain for the PDSCH is present as the UE failed to decode both the PDCCH and PDSCH for the first transmission.

[0075] The two look-up tables (214, 216, FIG. 2) for link adaptation of retransmissions may be determined or computed offline and stored locally in the BS/gNB.

[0076] In a second embodiment, the look-up tables may be calculated to return the PDCCH aggregation level and PDSCH MCS instead of BLERs. Output of the tables can be BLERSs for control and data channels, or may be the MCS of data channel and the CCE aggregation level for control channel.

[0077] Some non-limiting examples are shown in the tables below. Those are computed for a typical downlink URLLC case, were the URLLC payload is 50 bytes, and the size of the scheduling grant (DCI in PDCCH) is 16 bytes. We assume that the probability of ACK-2-NACK, NACK-2-ACK. and DTX-2-ACK equals le-5. First examples are for the case where the outage target is 1e-5, assuming that the delay budget allows for maximum one HARQ retransmission. Chase combining is assumed in these examples.

[0078] The table here show examples for first transmissions: 1 of inputs SINR [dB] Output PDCCH BLER Output PDSCH BLER (reported as CQI) (these would map to CCE — | (these would map to MCS O aggregation Level) of PDSCH)

O ;

O = k >= -

I a a 2 [0079] The table below shows the table for a first HARQ retransmission, O 28

O O

N triggered based on reception of a NACK. Notice that since HARQ Chase Combining is assumed, the PDSCH is transmitted with the same MCS as the original transmission, and hence the BLER for the PDSCH is not given in the table. oper

[0080] Second table — case 2 of Retransission (HARQ combining at UE is available)— BS can transmit data at same MCS, and transmit PDCCH with higher aggregation level (DCI transmitted with more resources — use more resources than first transmission, to improve chances data will be received) than was used in first transmission to increase reliability of the retransmission.

[0081] The next table shows the BLER settings (which may be mapped to link adaptation settings, such as aggregation levels and/or MCS) for a retransmission triggered by reception of discontinuous transmission (DTX) or HARQ timeout (instead of ACK/NACK). Notice that for such cases, the UE has not decoded either the PDCCH and PDSCH of the first transmission. Lower block error rates are shown, so this causes BS to use more resources to transmit at higher aggregation level, and lower MCS to meet these lower BLER. This case here uses lower MCS to reach lower PDSCH BLER (because no chase combining is available in this case).

[0082] o 2 p ==

N : z [0083] Examples are shown for Chase combining, but also would be applicable = for IR combining— incremental redundancy. Both are examples of HARQ combining 2 O 29

O O N

(where a HARQ retransmission may be combined with a previous retransmission at UE to improve probability of decoding the data).

[0084] Next, we show similar set of tables for the case where the outage probability (reliability target) is even more strict is 1e-7, while otherwise assuming the same PDCCH DCI size, PDSCH payload size, and uplink control signalling errors. A lower BLER may be used — maybe a little bit lower in first transmission, but significantly lower in second transmission.

[0085] The table here show example for first transmissions: ===

[0086] The table here shows the table for a first HARO retransmission, triggered based on reception of a NACK. e

[0087] The next table shows the BLER settings for a retransmission triggered by reception of DTX (e.g., no NACK received and HARO timeout for initial transmission). e pt —”Hnao tj jht=T=—=D ; z © [0088] Notice that these tables are meant as illustrative examples only. Those 3 30 >

N tables clearly show that the BLER for PDCCH and PDSCH may be set differently depending on the various cases; e.g., depending on the SINR or COI of the link or channel, whether a transmission is a first transmission or a HARQ retransmission, the outage probability equals (reliability target), and a cause for the retransmission.

[0089] According to an example embodiment, an optimization problem may be formulated to minimize the average number of allocated resources (jointly for both data and control channel) subject to URLLC reliability and latency requirements. The problem can be expressed as follows:

[0090] min Niotat = my + dy + PET (1 = PIG — PA) (my + dy) + PA (1 — P(A — Pr) (my + dy) + PIA — PM) (my + da)

[0091] Subject to: Pith; < Piarget

[0092] Po, = p pm? (1 pi PP) + pm p? + p? pe + PA2(1 - pm _ pm? + pi pm?) + pma(Pm(1 _ Ppm23(1 _ PII) + Pna((1 _ pm _ pm? + pm Pm) (PH! — PI) o

O N O

I a a

LO

K O 31

O O N

[0093] m; Metadata (control channel information) blocklength in i-th fn

[0094] Some Example Benefits:

[0095] The PDCCH and PDSCH link adaptation is selected jointly to minimize the used radio resources, while still fulling the users QoS requirements (this is a clear advantage over prior art)

[0096] The PDCCH and PDSCH link adaptations may be based upon or made a function of whether the transmission is a first transmission or a retransmission. And in case of retransmissions, what the cause of the retransmission was, as well as the increased reliability due to getting closer to the latency limit.

o [0097] Example 1. FIG. 3 is a flow chart illustrating operation of a base station > according to an example embodiment. Operation 310 includes determining, by a base O station, a payload size for a downlink control channel between the base station and a user = device, a payload size for a downlink data channel between the base station and the user I device, and a channel quality indication (CQT) indicating a link quality between the base a o station and the user device, wherein the payload of the downlink control channel provides

N D 32 >

N scheduling information for the downlink data channel. And, operation 320 includes jointly determining, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel.

[0098] Example 2. The method of example 1, further comprising determining, by the base station, a reliability target for the downlink control channel; and determining, by the base station, a reliability target for the downlink data channel.

[0099] Example 3. The method of any of examples 1-2, further comprising: allocating, by the base station based on the link adaptation setting for both of the downlink control channel and the downlink data channel, resources for transmission of control information via the downlink control channel and resources for transmission of data via the downlink data channel.

[00100] Example 4. The method of any of examples 1-3, wherein the jointly determining the link adaptation setting for both of the downlink control channel and the downlink data channel comprises: determining, by the base station, a first target block error rate (BLER) for the downlink control channel; and determining, by the base station, a second target block error rate (BLER) for the downlink data channel, wherein the first target BLER and the second target BLER are used by the BS to allocate downlink resources.

[00101] Example 5. The method of any of examples 1-4, wherein the jointly determining the link adaptation setting for both of the downlink control channel and the downlink data channel comprises: determining, by the base station, an aggregation level or a control channel element (CCE) aggregation level for the downlink control channel; and determining, by the base station, a modulation and coding scheme (MCS) to be used O for a downlink data transmission via the downlink data channel.

N [00102] Example 6. The method of any of examples 1-5, further comprising: 2 determining, by the base station, a transmission type of a data transmission for the —- downlink data channel, as either a first transmission of data or a retransmission of the E data, and a cause for retransmission if the transmission type is retransmission; wherein the jointly determining a link adaptation setting comprises jointly determining a link LO 33

O adaptation setting for both of the downlink control channel and the downlink data channel based at least on the transmission type for a data transmission via the downlink data channel, and based on the cause for retransmission if the transmission type is retransmission.

[00103] Example 7. The method of any of examples 1-6, further comprising: determining, by the base station, a transmission type of a data transmission for the downlink data channel, as a retransmission; determining, by the base station based on a presence or absence of feedback from the user device with respect to a first or initial transmission of the data, at least one of: a cause for the retransmission of data via the downlink data channel, or whether or not a Hybrid ARO (HARO) combining may be performed at the user device based on the retransmission of data via the downlink data channel; wherein the jointly determining a link adaptation setting comprises jointly determining, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel based at least on the transmission type for a data transmission via the downlink data channel being a retransmission, and based on at least one of the cause for the retransmission or whether or not a Hybrid ARO (HARO) combining may be performed at the user device based on the retransmission of data.

[00104] Example 8. The method of any of examples 6-7 wherein the cause for retransmission comprises determining at least one of the following as the cause for the retransmission of data via the downlink data channel: a negative acknowledgement (NACK) is received by the base station from the user device for a first or initial transmission of the data; or a discontinuous transmission is detected by the base station for the first or initial transmission of the data, in which neither an acknowledgement O (ACK) nor a negative acknowledgement (NACK) is received by the base station for the N first or initial transmission of the data.

2 [00105] Example 9. An apparatus comprising means for performing the method of - any of examples 1-8.

E [00106] Example 10. A non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are O 34 > &

configured to cause a computing system to perform the method of any of examples 1-8.

[00107] Example 11. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the method of any of examples 1-8.

[00108] Example 12. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to: determine, by a base station, a payload size for a downlink control channel between the base station and a user device, a payload size for a downlink data channel between the base station and the user device, and a channel quality indication (CQI) indicating a link quality between the base station and the user device, wherein the payload of the downlink control channel provides scheduling information for the downlink data channel; and jointly determine, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel.

[00109] Example 13. FIG. 4 is a flow chart illustrating operation of a base station according to an example embodiment. Operation 410 includes determining, by the base station, a transmission type of a data transmission for a downlink data channel between the base station and a user device, as a retransmission of data. Operation 420 incudes determining, by the base station based on a presence or absence of feedback from the user device with respect to an initial or first transmission of the data, at least one of the following: a cause for the retransmission of the data via the downlink data channel, or whether or not a Hybrid ARQ (HARQ) combining is available to the user device based O on the retransmission of the data via the downlink data channel. Operation 430 includes N jointly determining, by the base station, a link adaptation setting for both of the downlink 2 data channel and a downlink control channel based at least on the transmission type being —- a retransmission, and based on at least one of the cause for the retransmission or whether E or not a Hybrid ARO (HARO) combining may be performed at the user device based on the retransmission of data, wherein a payload of the downlink control channel provides LO 35

O scheduling information for the downlink data channel.

[00110] Example 14. The method of example 13, further comprising: determining, by the base station, a reliability target for the downlink control channel; and determining, by the base station, a reliability target for the downlink data channel.

[00111] Example 15. The method of any of examples 13-14, further comprising; allocating, by the base station based on at least the link adaptation setting for both of the downlink control channel and the downlink data channel, resources for transmission of control information via the downlink control channel and resources for transmission of data via the downlink data channel.

[00112] Example 16. The method of any of examples 13-15, wherein the jointly determining the link adaptation setting for both of the downlink control channel and the downlink data channel comprises: determining, by the base station, a first target block error rate (BLER) for the downlink control channel; and determining, by the base station, a second target block error rate (BLER) for the downlink data channel, wherein the first BLER and the second BLER are used by the BS to allocate downlink resources.

[00113] Example 17. The method of any of examples 13-16, wherein the jointly determining the link adaptation setting for both of the downlink control channel and the downlink data channel comprises: determining, by the base station, an aggregation level or a control channel element (CCE) aggregation level for the downlink control channel, and determining, by the base station, a modulation and coding scheme (MCS) to be used for a downlink data transmission via the downlink data channel.

[00114] Example 18. The method of any of examples 13-17 wherein the cause for retransmission comprises determining at least one of the following as the cause for O retransmission of data via the downlink data channel: a negative acknowledgement N (NACK) is received by the base station from the user device for a first or initial 2 transmission of the data; or a discontinuous transmission is detected by the base station —- for the first or initial transmission of the data, in which neither an acknowledgement E (ACK) nor a negative acknowledgement (NACK) is received by the base station for the first or initial transmission of the data.

LO 36

N

[00115] Example 19. An apparatus comprising means for performing the method of any of examples 13-18.

[00116] Example 20. A non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are configured to cause a computing system to perform the method of any of examples 13-

18.

[00117] Example 21. An apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the method of any of examples 13-18.

[00118] FIG. 5 is a block diagram of a wireless station (e.g., AP, BS or user device/UE, or other network node) 1000 according to an example embodiment. The wireless station 1000 may include, for example, one or more (e.g., two as shown in FIG. 5) RF (radio frequency) or wireless transceivers 1002A, 1002B, where each wireless transceiver includes a transmitter to transmit signals and a receiver to receive signals. The wireless station also includes a processor or control unit/entity (controller) 1004 to execute instructions or software and control transmission and receptions of signals, and a memory 1006 to store data and/or instructions.

[00119] Processor 1004 may also make decisions or determinations, generate frames, packets or messages for transmission, decode received frames or messages for further processing, and other tasks or functions described herein. Processor 1004, which may be a baseband processor, for example, may generate messages, packets, frames or other signals for transmission via wireless transceiver 1002 (1002A or 1002B). Processor O 1004 may control transmission of signals or messages over a wireless network, and may N control the reception of signals or messages, etc., via a wireless network (e.g., after being 2 down-converted by wireless transceiver 1002, for example). Processor 1004 may be - programmable and capable of executing software or other instructions stored in memory E or on other computer media to perform the various tasks and functions described above, such as one or more of the tasks or methods described above. Processor 1004 may be (or O 37 >

N may include), for example, hardware, programmable logic, a programmable processor that executes software or firmware, and/or any combination of these. Using other terminology, processor 1004 and transceiver 1002 together may be considered as a wireless transmitter/receiver system, for example.

[00120] In addition, referring to FIG. 5, a controller (or processor) 1008 may execute software and instructions, and may provide overall control for the station 1000, and may provide control for other systems not shown in FIG. 5, such as controlling input/output devices (e.g., display, keypad), and/or may execute software for one or more applications that may be provided on wireless station 1000, such as, for example, an email program, audio/video applications, a word processor, a Voice over IP application, or other application or software.

[00121] In addition, a storage medium may be provided that includes stored instructions, which when executed by a controller or processor may result in the processor 1004, or other controller or processor, performing one or more of the functions or tasks described above.

[00122] According to another example embodiment, RF or wireless transceiver(s) 1002A/1002B may receive signals or data and/or transmit or send signals or data. Processor 1004 (and possibly transceivers 1002A/1002B) may control the RF or wireless transceiver 1002A or 1002B to receive, send, broadcast or transmit signals or data.

[00123] The embodiments are not, however, restricted to the system that is given as an example, but a person skilled in the art may apply the solution to other communication systems. Another example of a suitable communications system is the 5G system. It is assumed that network architecture in 5G will be guite similar to that of the O LTE-advanced. 5G is likely to use multiple input — multiple output (MIMO) antennas, N many more base stations or nodes than the LTE (a so-called small cell concept), 2 including macro sites operating in co-operation with smaller stations and perhaps also - employing a variety of radio technologies for better coverage and enhanced data rates. E [00124] It should be appreciated that future networks will most probably utilise network functions virtualization (NFV) which is a network architecture concept that O 38 >

N proposes virtualizing network node functions into “building blocks” or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications this may mean node operations may be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labour between core network operations and base station operations may differ from that of the LTE or even be non-existent.

[00125] Embodiments of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Embodiments may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. Embodiments may also be provided on a computer readable medium or computer readable storage medium, which may be a non-transitory medium. Embodiments of the various techniques may also include embodiments provided via transitory signals or media, and/or programs and/or software embodiments that are downloadable via the Internet or other network(s), either wired networks and/or wireless networks. In addition, embodiments may be provided via machine type communications (MTC), and also via an Internet of Things (IOT).

O [00126] The computer program may be in source code form, object code form, or N in some intermediate form, and it may be stored in some sort of carrier, distribution 2 medium, or computer readable medium, which may be any entity or device capable of - carrying the program. Such carriers include a record medium, computer memory, read- E only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power O 39 > &

needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers.

[00127] Furthermore, embodiments of the various techniques described herein may use a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the embodiment and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers,...) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals. The rise in popularity of smartphones has increased interest in the area of mobile cyber-physical systems. Therefore, various embodiments of techniques described herein may be provided via one or more of these technologies.

[00128] A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit or part of it suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[00129] Method steps may be performed by one or more programmable processors executing a computer program or computer program portions to perform functions by operating on input data and generating output. Method steps also may be performed by, O and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA N (field programmable gate array) or an ASIC (application-specific integrated circuit).

2 [00130] Processors suitable for the execution of a computer program include, by —- way of example, both general and special purpose microprocessors, and any one or more E processors of any kind of digital computer, chip or chipset. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or LO 40 &

both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g, magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[00131] To provide for interaction with a user, embodiments may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a user interface, such as a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

[00132] Embodiments may be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer O having a graphical user interface or a Web browser through which a user can interact N with an embodiment, or any combination of such back-end, middleware, or front-end 2 components. Components may be interconnected by any form or medium of digital data —- communication, e.g., a communication network. Examples of communication networks E include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.

[00133] While certain features of the described embodiments have been illustrated O 41 > &

as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the various embodiments.

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Claims (17)

WHAT IS CLAIMED IS:

1. A method comprising: determining, by a base station, a payload size for a downlink control channel between the base station and a user device, a payload size for a downlink data channel between the base station and the user device, and a channel quality indication (CQI) indicating a link quality between the base station and the user device, wherein the payload of the downlink control channel provides scheduling information for the downlink data channel; and jointly determining, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel.

2. The method of claim 1, further comprising: determining, by the base station, a reliability target for the downlink control channel; and determining, by the base station, a reliability target for the downlink data channel.

3. The method of any of claims 1-2, further comprising; allocating, by the base station based on the link adaptation setting for both of the downlink control channel and the downlink data channel, resources for transmission of control information via the downlink control channel and resources for transmission of data via the downlink data channel. O

4. The method ofany of claims 1-3, wherein the jointly determining the link N adaptation setting for both of the downlink control channel and the downlink data 2 channel comprises: —- determining, by the base station, a first target block error rate (BLER) for the E downlink control channel; and

R LO 43

O determining, by the base station, a second target block error rate (BLER) for the downlink data channel, wherein the first target BLER and the second target BLER are used by the BS to allocate downlink resources.

5. The method of any of claims 1-4, wherein the jointly determining the link adaptation setting for both of the downlink control channel and the downlink data channel comprises: determining, by the base station, an aggregation level or a control channel element (CCE) aggregation level for the downlink control channel; and determining, by the base station, a modulation and coding scheme (MCS) to be used for a downlink data transmission via the downlink data channel.

6. The method of any of claims 1-5, further comprising; determining, by the base station, a transmission type of a data transmission for the downlink data channel, as either a first transmission of data or a retransmission of the data, and a cause for retransmission if the transmission type is retransmission; wherein the jointly determining a link adaptation setting comprises jointly determining a link adaptation setting for both of the downlink control channel and the downlink data channel based at least on the transmission type for a data transmission via the downlink data channel, and based on the cause for retransmission if the transmission type is retransmission.

7. The method of any of claims 1-5, further comprising; O determining, by the base station, a transmission type of a data transmission for the N downlink data channel, as a retransmission; 2 determining, by the base station based on a presence or absence of feedback from —- the user device with respect to a first or initial transmission of the data, at least one of: a E cause for the retransmission of data via the downlink data channel, or whether or nota

E O 44 &

Hybrid ARQ (HARQ) combining may be performed at the user device based on the retransmission of data via the downlink data channel; wherein the jointly determining a link adaptation setting comprises jointly determining, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel based at least on the transmission type for a data transmission via the downlink data channel being a retransmission, and based on at least one of the cause for the retransmission or whether or not a Hybrid ARQ (HARQ) combining may be performed at the user device based on the retransmission of data.

8. The method of any of claims 6-7 wherein the cause for retransmission comprises determining at least one of the following as the cause for the retransmission of data via the downlink data channel: a negative acknowledgement (NACK) is received by the base station from the user device for a first or initial transmission of the data; or a discontinuous transmission is detected by the base station for the first or initial transmission of the data, in which neither an acknowledgement (ACK) nor a negative acknowledgement (NACK) is received by the base station for the first or initial transmission of the data.

9. An apparatus comprising means for performing the method of any of claims 1-8.

10. An apparatus comprising: O at least one processor; and N at least one memory including computer program code; 2 the at least one memory and the computer program code configured to, with the at —- least one processor, cause the apparatus to: E determine, by a base station, a payload size for a downlink control channel between the base station and a user device, a payload size for a downlink data channel O 45 > &

between the base station and the user device, and a channel quality indication (CQI) indicating a link quality between the base station and the user device, wherein the payload of the downlink control channel provides scheduling information for the downlink data channel; and jointly determine, by the base station, a link adaptation setting for both of the downlink control channel and the downlink data channel.

11. A method comprising: determining, by the base station, a transmission type of a data transmission for a downlink data channel between the base station and a user device, as a retransmission of data; determining, by the base station based on a presence or absence of feedback from the user device with respect to an initial or first transmission of the data, at least one of the following: a cause for the retransmission of the data via the downlink data channel, or whether or not a Hybrid ARQ (HARQ) combining is available to the user device based on the retransmission of the data via the downlink data channel; and jointly determining, by the base station, a link adaptation setting for both of the downlink data channel and a downlink control channel based at least on the transmission type being a retransmission, and based on at least one of the cause for the retransmission or whether or not a Hybrid ARQ (HARQ) combining may be performed at the user device based on the retransmission of data, wherein a payload of the downlink control channel provides scheduling information for the downlink data channel. O

12. The method of claim 11, further comprising: N determining, by the base station, a reliability target for the downlink control 2 channel; and —- determining, by the base station, a reliability target for the downlink data channel. = a

13. The method of any of claims 11-12, further comprising; LO 46 &

allocating, by the base station based on at least the link adaptation setting for both of the downlink control channel and the downlink data channel, resources for transmission of control information via the downlink control channel and resources for transmission of data via the downlink data channel.

14. The method of any of claims 11-13, wherein the jointly determining the link adaptation setting for both of the downlink control channel and the downlink data channel comprises: determining, by the base station, a first target block error rate (BLER) for the downlink control channel; and determining, by the base station, a second target block error rate (BLER) for the downlink data channel, wherein the first BLER and the second BLER are used by the BS to allocate downlink resources.

15. The method of any of claims 11-14, wherein the jointly determining the link adaptation setting for both of the downlink control channel and the downlink data channel comprises: determining, by the base station, an aggregation level or a control channel element (CCE) aggregation level for the downlink control channel; and determining, by the base station, a modulation and coding scheme (MCS) to be used for a downlink data transmission via the downlink data channel.

16. The method of any of claims 11-15 wherein the cause for retransmission O comprises determining at least one of the following as the cause for N retransmission of data via the downlink data channel: 2 a negative acknowledgement (NACK) is received by the base station from the - user device for a first or initial transmission of the data; or E a discontinuous transmission is detected by the base station for the first or initial transmission of the data, in which neither an acknowledgement (ACK) nor a negative O 47 > &

acknowledgement (NACK) is received by the base station for the first or initial transmission of the data.

17. An apparatus comprising means for performing the method of any of claims 11-16. o

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MN BD 48

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