Apparatus, method and computer program

Abstract

The present disclosure relates to an apparatus comprising at least one processor and at least one memory comprising computer code for one or more programs, the at least one memory and the computer code are configured to, with the at least one processor, cause the apparatus to at least: send (1700) a radio frequency impairment indication to a network node; and receiving (1702), from the network node, a physical downlink control channel having a physical downlink control channel configuration, the physical downlink control channel configuration being determined based on the radio frequency impairment indication.

Description

[0001] Field of the disclosure

[0002] The present disclosure relates to an apparatus, a method, and a computer program for transmitting and receiving a physical downlink control channel in a communication system.

[0003] For the purposes of the present disclosure, the phrase "at least one of A or B", "at least one of A and B", "A and / or B" means (A), (B), or (A and B). For the purposes of the present disclosure, the phrases "A or B" and "A and / or B" mean (A), (B), or (A and B). For the purposes of the present disclosure, the phrase "A, B, and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). Background art

[0004] A communication system may be regarded as a facility that enables a communication session between two or more entities (such as communication devices, base stations, and / or other nodes) by providing a carrier between various entities involved in a communication path.

[0005] A communication system may be a wireless communication system. Examples of wireless systems include public land mobile networks (PLMNs) operating based on radio standards such as those provided by 3GPP, satellite-based communication systems, and different wireless local area networks, such as wireless local area network (WLAN). Wireless systems can generally be divided into cells and are thus often referred to as cellular systems.

[0006] Communication systems and associated devices typically operate according to a given standard or specification that sets out what the various entities associated with the system are allowed to do and how this should be achieved. Communication protocols and / or parameters that should be used for connections are also typically configured. An example of a standard is the so-called 5G standard. Summary of the invention

[0007] According to one aspect, there is provided an apparatus comprising at least one processor and at least one memory, the at least one memory including computer code for one or more programs, the at least one memory and the computer code being configured to, with the at least one processor, cause the apparatus to at least: send a radio frequency impairment indication to a network node; and receive from the network node a physical downlink control channel having a physical downlink control channel configuration determined based on the radio frequency impairment indication.

[0008] The at least one memory and the computer code may be configured to, with the at least one processor, cause the apparatus to at least: monitor a physical downlink control channel having a physical downlink control channel configuration determined based on a radio frequency impairment indication.

[0009] The at least one memory and the computer code may be configured to cause the apparatus, using the at least one processor, to at least: blindly monitor physical downlink control channels having different physical downlink control channel configurations.

[0010] The network node may be a base station.

[0011] The radio frequency impairment indication may explicitly indicate a radio frequency impairment class.

[0012] The radio frequency impairment indication may depend on the severity of the radio frequency impairment.

[0013] The severity of the radio frequency impairment at the apparatus may include at least one of the following: high radio frequency impairment; medium radio frequency impairment; or low radio frequency impairment.

[0014] The radio frequency impairment indication may depend on the type of radio frequency impairment.

[0015] The type of radio frequency impairment at the apparatus may include at least one of the following: phase noise impairment; quantization impairment; in-phase and quadrature imbalance impairment; power amplifier non-linearity, time jitter; or carrier frequency offset.

[0016] The radio frequency impairment indication may depend on the subtype of radio frequency impairment at the user equipment.

[0017] The radio frequency impairment indication may implicitly indicate the radio frequency impairment class assigned to the apparatus.

[0018] The radio frequency impairment indication may include at least one of the following: the desired reference signal configuration of the apparatus; the quality of the local oscillator at the apparatus; the resolution of the analog-to-digital converter at the apparatus; or the physical random access channel preamble used by the apparatus in an initial access phase.

[0019] The radio frequency impairment indication may be sent via at least one of the following: capability information signaling; physical random access channel signaling; or radio resource control signaling.

[0020] The desired reference signal configuration may include a desired phase-tracking reference signal configuration.

[0021] The radio frequency impairment indication may be specific to at least one of the bandwidth, subcarrier spacing, or frequency carrier used by the apparatus.

[0022] Determining the physical downlink control channel configuration by the apparatus may include determining at least one of the following: reference signal configuration; subcarrier spacing configuration; aggregation level configuration; control channel element configuration; resource element group configuration; resource element group bundling configuration; modulation scheme configuration; or code rate configuration.

[0023] The reference signal configuration includes the number of reference signal symbols.

[0024] Determining the reference signal configuration may include determining at least one of the following: the pattern of reference signal symbols; or the transmission power of the reference signal symbols.

[0025] Determining the pattern of the reference signal symbols includes: determining a continuous pattern, where the reference signal symbols span multiple consecutive blocks; or determining a discontinuous pattern, where the reference signal symbols span multiple non - consecutive blocks.

[0026] Determining the reference signal configuration may include determining the reference signal configuration on at least one of the following: a control channel element or multiple control channel elements; a resource element group or multiple resource element groups; or a block or multiple blocks.

[0027] Determining the reference signal configuration may include determining at least one of the following: a phase - tracking reference signal configuration; or a demodulation reference signal configuration.

[0028] Determining the reference signal configuration may be based on at least one of the following: the aggregation level used by the device; the coding rate used by the device; or the waveform used by the device to transmit the physical downlink control channel.

[0029] The lower the aggregation level, the higher the number of reference signal symbols may be.

[0030] The lower the aggregation level, the higher the transmission power of the reference signal symbols may be.

[0031] The waveform used to transmit the physical downlink control channel may include a single - carrier waveform or a multi - carrier waveform.

[0032] The single - carrier waveform may be provided by at least one of the following: a discrete Fourier transform spread orthogonal frequency - division multiplexing system; a known - tail discrete Fourier transform spread orthogonal frequency - division multiplexing system; a single - carrier frequency - domain equalization system; a single - carrier time - domain equalization system.

[0033] The multi - carrier waveform may be provided by a cyclic prefix orthogonal frequency - division multiplexing system.

[0034] Determining the aggregation level configuration includes determining a minimum aggregation level.

[0035] The higher the coding rate (i.e., the lower the aggregation level), the more harmful the radio - frequency impairments may be. Therefore, the aggregation level may be equal to or greater than the minimum aggregation level to mitigate radio - frequency impairments.

[0036] The physical downlink control channel configuration may be determined by the device based on a radio - frequency impairment indication; or, the physical downlink control channel configuration may be determined by a network node based on a radio - frequency impairment indication and received by the device from the network node.

[0037] According to one aspect, a device is provided that includes components for: sending a radio frequency impairment indication to a network node; and receiving from the network node a physical downlink control channel having a physical downlink control channel configuration determined based on the radio frequency impairment indication.

[0038] According to one aspect, a device is provided that includes circuitry configured to: send a radio frequency impairment indication to a network node; and receive from the network node a physical downlink control channel having a physical downlink control channel configuration determined based on the radio frequency impairment indication.

[0039] According to one aspect, a method is provided that includes: sending a radio frequency impairment indication to a network node; and receiving from the network node a physical downlink control channel having a physical downlink control channel configuration determined based on the radio frequency impairment indication.

[0040] According to one aspect, a computer program including computer-executable code is provided that, when run on at least one processor, is configured to: send a radio frequency impairment indication to a network node; and receive from the network node a physical downlink control channel having a physical downlink control channel configuration determined based on the radio frequency impairment indication.

[0041] According to one aspect, a device is provided that includes at least one processor and at least one memory, the at least one memory including computer code for one or more programs, the at least one memory and the computer code being configured to, using the at least one processor, cause the device to at least: receive a radio frequency impairment indication from a user equipment; determine a physical downlink control channel configuration based on the radio frequency impairment indication; and send to the user equipment a physical downlink control channel having the physical downlink control channel configuration.

[0042] According to one aspect, a device is provided that includes components for: receiving a radio frequency impairment indication from a user equipment; determining a physical downlink control channel configuration based on the radio frequency impairment indication; and sending to the user equipment a physical downlink control channel having the physical downlink control channel configuration.

[0043] According to one aspect, a device is provided that includes circuitry configured to: receive a radio frequency impairment indication from a user equipment; determine a physical downlink control channel configuration based on the radio frequency impairment indication; and send to the user equipment a physical downlink control channel having the physical downlink control channel configuration.

[0044] According to one aspect, a method is provided, including: receiving a radio frequency impairment indication from a user equipment; determining a physical downlink control channel configuration based on the radio frequency impairment indication; and sending a physical downlink control channel having the physical downlink control channel configuration to the user equipment.

[0045] According to one aspect, a computer program including computer-executable code is provided, the computer-executable code being configured to, when run on at least one processor: receive a radio frequency impairment indication from a user equipment; determine a physical downlink control channel configuration based on the radio frequency impairment indication; and send a physical downlink control channel having the physical downlink control channel configuration to the user equipment.

[0046] According to one aspect, a computer-readable medium is provided, including program instructions stored thereon for performing at least one of the above methods.

[0047] According to one aspect, a non-transitory computer-readable medium is provided, including program instructions stored thereon for performing at least one of the above methods.

[0048] According to one aspect, a non-volatile tangible storage medium is provided, including program instructions stored thereon for performing at least one of the above methods.

[0049] Above, many different aspects have been described. It should be understood that additional aspects can be provided by any combination of two or more of the above aspects.

[0050] Various other aspects are also described in the following detailed description and the appended claims.

[0051] List of Abbreviations

[0052] AF: Application Function

[0053] AL: Aggregation Level

[0054] AMF: Access and Mobility Management Function

[0055] API: Application Programming Interface

[0056] BS: Base Station

[0057] CCE: Control Channel Element

[0058] CEPT: Conference of European Posts and Telecommunications

[0059] CU: Centralized Unit

[0060] CP-OFDM: Cyclic Prefix Orthogonal Frequency Division Multiplexing

[0061] DCI: Downlink Control Information

[0062] DL: Downlink

[0063] DMRS: Demodulation Reference Signal

[0064] DU: Distributed Unit

[0065] ECC: Electronic Communications Committee

[0066] EIRP: Effective Isotropic Radiated Power

[0067] gNB: gNodeB

[0068] GSM: Global System for Mobile Communications

[0069] HSS: Home Subscriber Server

[0070] ICI: Inter-Carrier Interference

[0071] IoT: Internet of Things (KT) DFT-s-OFDM: (Known Tail) Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing LTE: Long Term Evolution

[0072] MAC: Medium Access Control

[0073] MCS: Modulation and Coding Scheme

[0074] MS: Mobile Station

[0075] MTC: Machine Type Communication

[0076] NEF: Network Exposure Function

[0077] NF: Network Function

[0078] NR: New Radio

[0079] NRF: Network Repository Function

[0080] OBO: Output Back-Off

[0081] OFDM: Orthogonal Frequency Division Multiplexing

[0082] PDCCH: Physical Downlink Control Channel

[0083] PDU: Packet Data Unit

[0084] PN: Phase Noise

[0085] PT-RS: Phase Tracking Reference Signal

[0086] RAM: Random Access Memory (R)AN: (Radio) Access Network

[0087] RE: Resource Element

[0088] REG: Resource Element Group

[0089] RF: Radio Frequency

[0090] ROM: Read Only Memory

[0091] RS: Reference Signal

[0092] SCS: Sub - Carrier Spacing

[0093] SC - FDE: Single - Carrier Frequency - Domain Equalization

[0094] SC - TDE: Single - Carrier Time - Domain Equalization

[0095] SMF: Session Management Function

[0096] TR: Technical Report

[0097] TS: Technical Specification

[0098] UE: User Equipment

[0099] UL: Uplink

[0100] UMTS: Universal Mobile Telecommunications System

[0101] 3GPP: 3rd Generation Partnership Project

[0102] 5G: 5th Generation

[0103] 5GC: 5G Core Network

[0104] 5GS: 5G System Description of the Drawings

[0105] Embodiments will now be described by way of example only with reference to the drawings, wherein:

[0106] Figure 1 A schematic representation of a conventional 5G system is shown;

[0107] Figure 2 A schematic representation of a control device is shown;

[0108] Figure 3 A schematic representation of a user equipment is shown;

[0109] Figure 4 A schematic representation of the transmission chain of a cyclic prefix orthogonal frequency division multiplexing system is shown;

[0110] Figure 5 A schematic representation of the transmission chain of a discrete Fourier transform spread orthogonal frequency division multiplexing system is shown;

[0111] Figure 6 Shows a schematic representation of the transmission chain of a single - carrier frequency - domain equalization system;

[0112] Figure 7 Shows a schematic representation of the mapping of control channel elements to resource element groups of the physical downlink control channel in a conventional 5G system;

[0113] Figure 8 Shows Table 7.3.2.1 - 1 of 3GPP TS 38.211, which specifies the relationship between the aggregation level of the physical downlink control channel and the number of control channel elements in a conventional 5G system;

[0114] Figure 9 Shows a table specifying the relationship between the aggregation level of the physical downlink control channel, the number of control channel elements, the number of resource element groups, the number of resource elements, the number of phase - tracking reference signal resource elements, the number of demodulation reference signal resource elements, the number of encoded / decoded control data resource elements, and the total number of bits for the encoded / decoded control data in a conventional 5G system;

[0115] Figure 10 Shows Table 5.1.6.3 - 1 and Table 5.1.6.3 - 2 of TS 38.214, which define the phase - tracking reference signal patterns (cyclic - prefix orthogonal frequency - division multiplexing) for the physical uplink shared channel in a conventional 5G system when transform precoding is disabled;

[0116] Figure 11 Shows Table 6.2.3.2 - 1 of TS 38.214, which defines the phase - tracking reference signal patterns (discrete Fourier transform - spread orthogonal frequency - division multiplexing) for the physical uplink shared channel in a conventional 5G system when transform precoding is enabled;

[0117] Figure 12 Shows an example of different control channel element configurations when the physical downlink control channel is to be transmitted using a single - carrier waveform;

[0118] Figure 13 Shows a table specifying the relationship between the aggregation level of the physical downlink control channel, the number of control channel elements, the number of resource element groups, the number of resource elements, the number of phase - tracking reference signal resource elements, the number of demodulation reference signal resource elements, the number of encoded / decoded control data resource elements, and the total number of bits for the encoded / decoded control data;

[0119] Figure 14Shows different time-domain phase tracking reference signal configurations for the physical downlink control channel based on different radio frequency impairment indications from a user equipment, these configurations having different modes and the same or different numbers of phase tracking reference signal symbols;

[0120] Figure 15 Shows different phase tracking reference signal configurations for the physical downlink control channel (when the aggregation level is 16) based on different radio frequency impairment indications from a user equipment and the required estimation accuracy, these configurations having different numbers of phase tracking reference signal symbols;

[0121] Figure 16 Shows example phase tracking reference signal configurations and demultiplexing reference signal configurations for control channel elements occupying one or two orthogonal frequency division multiplexing symbols; Figure 17 Shows a block diagram of a method performed by a user equipment for receiving a physical control channel;

[0122] Figure 18 Shows a block diagram of a method performed by a network node for transmitting a physical control channel; and

[0123] Figure 19 Shows a schematic representation of a non-volatile memory medium storing instructions which, when executed by a processor, allow the processor to perform Figure 17 and Figure 18 one or more of the steps of the method of

[0124] Detailed Description of the Drawings

[0125] Hereinafter, certain embodiments are explained with reference to a mobile communication device capable of communicating via a wireless cellular system and a mobile communication system serving such a mobile communication device. Before explaining the exemplary embodiments in detail, reference is made to Figure 1 、 Figure 2 and Figure 3 to briefly explain certain general principles of a wireless communication system, its access system and a mobile communication device to assist in understanding the technology underlying the described examples.

[0126] Figure 1 Shows a schematic representation of a conventional 5G system (5GS). The 5GS may include a user equipment (UE), a (radio) access network ((R)AN), a 5G core network (5GC), one or more application functions (AF) and one or more data networks (DN).

[0127] The 5G (R)AN may include one or more gNodeB (gNB) distributed unit functions connected to one or more gNodeB (gNB) centralized unit functions.

[0128] 5GC may include an Access and Mobility Management Function (AMF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a User Data Management (UDM), a User Plane Function (UPF), and / or a Network Exposure Function (NEF).

[0129] Figure 2 FIG. illustrates a control device 200 for controlling the functions of a (R)AN or 5GC as Figure 1 shown. The control device may include at least one Random Access Memory (RAM) 211a, at least one Read Only Memory (ROM) 211b, at least one processor 212, 213, and an Input / Output Interface 214. The at least one processor 212, 213 may be coupled to the RAM 211a and the ROM 211b. The at least one processor 212, 213 may be configured to execute appropriate software code 215. The software code 215 may, for example, allow the execution of one or more steps to perform one or more aspects. The software code 215 may be stored in the ROM 211b. The control device 200 may be interconnected with another control device 200 that controls another function of the 5G (R)AN or 5GC. In some embodiments, each function of the (R)AN or 5GC includes a control device 200. In alternative embodiments, two or more functions of the (R)AN or 5GC may share a control device.

[0130] Figure 3 FIG. illustrates an example of a UE 300 (such as Figure 1 the UE illustrated above). The UE 300 may be provided by any device capable of transmitting and receiving radio signals. Non-limiting examples include a user equipment, a mobile station (MS), or a mobile device (such as a mobile phone or a so-called'smartphone'), a computer provided with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal data assistant (PDA) or a tablet computer provided with wireless communication capabilities, a Machine Type Communication (MTC) device, a Cellular Internet of Things (CIoT) device, or any combination thereof, etc. The UE 300 may provide, for example, data communication for carrying communications. The communication may be one or more of voice, email, text message, multimedia, data, machine data, etc.

[0131] The UE 300 may receive signals over the air or radio interface 307 via appropriate means for receiving, and may transmit signals via appropriate means for transmitting radio signals. In Figure 3 FIG., the transceiver device is schematically designated by block 306. The transceiver device 306 may be provided, for example, by radio components and an associated antenna arrangement. The antenna arrangement may be disposed inside or outside the mobile device.

[0132] The UE 300 may be provided with at least one processor 301, at least one memory ROM 302a, at least one RAM 302b, and other possible components 303 for assisting in performing, by software and hardware, the tasks it is designed to perform, including controlling access to the access system and communicating with other communication devices. The at least one processor 301 is coupled to the RAM 302b and the ROM 302a. The at least one processor 301 may be configured to execute appropriate software code 308. The software code 308 may, for example, permit the execution of one or more aspects. The software code 308 may be stored in the ROM 302a.

[0133] The processor, storage device, and other related control devices may be provided on a suitable circuit board and / or in a chipset. This feature is denoted by reference numeral 304. The device may optionally have a user interface, such as a keypad 305, a touch-sensitive screen or pad, a combination thereof, etc. Optionally, depending on the type of device, one or more of a display, a speaker, and a microphone may be provided.

[0134] One or more aspects of the present disclosure relate to sending a Physical Downlink Control Channel (PDCCH) from a BS to a UE. The PDCCH may schedule downlink (DL) transmissions to the UE and / or uplink (UL) transmissions from the UE.

[0135] One or more aspects of the present disclosure relate to sending a Physical Downlink Control Channel (PDCCH) from a BS to a UE when the UE experiences RF impairments. For example, when the BS and the UE operate in a sub-THz band (e.g., a band above 71 GHz), the UE may experience significant RF impairments.

[0136] In the NR Release 18 workshop and the email discussions prior to RAN#93-e, the use of single-carrier waveforms in both the uplink (UL) and the downlink (DL) and operation in the sub-THz band have been discussed. This was ultimately not implemented in NR Release 18 and was postponed to NR Release 19 or a subsequent release.

[0137] A single - carrier waveform can be provided by a discrete Fourier transform (with or without a known tail) extended orthogonal frequency - division multiplexing ((KT) DFT - s - OFDM) system, a single - carrier frequency - domain equalization (SC - FDE) system, or a single - carrier time - domain equalization (SC - TDE). In DFT - s - OFDM, each DFT - s - OFDM symbol can be prefixed with a cyclic prefix, while in KT - DFT - s - OFDM (also known as unique - word DFT - s - OFDM), there may be no cyclic prefix, but (multiple) known sequences of (multiple) predefined lengths can be inserted at the beginning (header) and / or end (tail) of each symbol before the DFT operation at the transmitter. In contrast, a multi - carrier waveform can be provided by a cyclic - prefix orthogonal frequency - division multiplexing (CP - OFDM) system.

[0138] Conventional 5GS uses a multi - carrier waveform provided by a CP - OFDM system on the DL and uses a multi - carrier waveform provided by a CP - OFDM system or a single - carrier waveform provided by DFT - s - OFDM on the UL.

[0139] Figure 4 A schematic representation of the transmission chain of a CP - OFDM system is shown. The operation of a CP - OFDM system is well - known and thus will not be described in detail.

[0140] Figure 5 A schematic representation of the transmission chain of a DFT - s - OFDM system is shown. The operation of a DFT - s - OFDM system is well - known and thus will not be described in detail.

[0141] Figure 6 A schematic representation of the transmission chain of an SC - FDE system is shown. The operation of an SC - FDE system is well - known and thus will not be described in detail.

[0142] A single - carrier waveform can achieve a higher equivalent isotropically radiated power (EIRP) (e.g., 60 dBm) with a smaller power - amplifier output power back - off (OBO) than a multi - carrier waveform. Therefore, compared with a multi - carrier waveform, a single - carrier waveform can reduce the cost, complexity, and power consumption of the hardware. In addition, compared with a multi - carrier waveform, a single - carrier waveform can be more robust to phase noise (PN) with lower complexity.

[0143] Although the spectrum including the sub - THz band is broad, it includes various usage restrictions, such as RR5.340, where all communications are prohibited (passive satellite band). The sub - THz band includes the W band (75 to 110 GHz), the D band (110 to 170 GHz), and other bands up to THz frequencies.

[0144] The Electronic Communications Committee (ECC) of the European Conference of Postal and Telecommunications Administrations (CEPT), the European telecommunications regulators, has approved two Recommendations for the Fixed Service (FS) above 92 GHz:

[0145] - Recommendation ECC / REC / (18)02 for the W band, in the frequency range 92 - 114.25 GHz (link); and

[0146] - Recommendation ECC / REC / (18)01 for the D band, in the frequency range 130 - 174.8 GHz (link).

[0147] In the discussion of NR Release 18, the W band was considered a possible option for operation in the sub - THz band. However, as mentioned above, operation in the sub - THz band was postponed to NR Release 19 or later releases.

[0148] The PDCCH can be used to carry downlink control information (DCI), which occupies a specific number of resource elements according to its aggregation level, and the aggregation level is quantified according to the control channel elements (CCEs) it occupies. The PDCCH can be transmitted in a control resource set (CORESET), which is a set of time / frequency resources where the PDCCH can be transmitted, and the UE knows the location to attempt to receive the PDCCH based on the CORESET. Based on the CORESET and the search space, the UE can attempt to blindly decode the PDCCH from certain locations and using certain aggregation levels. The CORESET can include a certain number of CCEs. A CCE can include a certain number of REGs.

[0149] When operating in higher millimeter - wave bands and the sub - THz band, the phase noise (PN) experienced by the UE may become increasingly important (if not a limiting factor). When operating in the sub - THz band, the BS can send a PDCCH including a phase - tracking reference signal (PT - RS) to the UE to allow the UE to mitigate the impact of PN. However, since traditional 5GS currently operates in lower frequency bands, the PN experienced by the UE is not important, and the BS does not send a PDCCH including PT - RS.

[0150] Future systems can be customized to account for different RF impairments at the UE. RF impairments can include, for example, the PN experienced by the UE or the quantization error experienced by the UE. RF impairments can be implementation - dependent. That is, each UE can have a specific implementation and may thus experience specific RF impairments.

[0151] The power amplifier power consumption increases with larger bandwidths such as in the sub - THz band, as well as with higher peak - to - average power ratio waveforms and larger OBO, due to operating in the low - power - amplifier efficiency region to obtain better linearity.

[0152] The power consumption of the analog-to-digital converter increases with the number of sampling rates (bandwidths) and quantization levels (resolution bits). For this reason, when operating in the sub-THz band, a lower analog-to-digital resolution may be preferred to offset the potentially inevitable power increase due to multiple-input multiple-output and larger bandwidths.

[0153] The available bandwidth in the spectrum including the sub-THz band is large, and thus it may be reasonable to reduce energy consumption at the expense of spectral efficiency. For example, the UE can use a low-resolution analog-to-digital converter and low-order modulation.

[0154] Assuming such a low-resolution analog-to-digital converter is used, it may become important to consider RF impairments at the UE when transmitting PDCCH from the BS to the UE.

[0155] The PN experienced by the UE can originate from local oscillators in upconversion and downconversion. Generally, in an OFDM-based system (e.g., a CP-OFDM or (KT) DFT-s-OFDM system), the effects of PN can include a common phase error that can be common to all subcarriers. The effects of PN can include inter-carrier interference (ICI), which can be unique to each subcarrier. The effects of PN can depend on the subcarrier spacing (SCS). The spectrum of PN can generally have a specific shape that highly depends on the implementation.

[0156] PN can be modeled as a combination of a Wiener component and a Gaussian component. The threshold of the dominant component can be approximated based on the following condition (1) (see S. Bicais and J. B. Dore, "Phase Noise Model Selection for Sub-THz Communications", IEEE Global Communications Conference (GLOBECOM) 2019, 2019, pp. 1-6, DOI: 10.1109 / GLOBECOM38437.2019.9013189).

[0157]

[0158] N can be the number of symbols per frame.

[0159] fc can be the oscillator inflection frequency.

[0160] T can be the symbol period (i.e., the reciprocal of the system bandwidth).

[0161] If the following condition (2) is satisfied, the dominant component can be the Gaussian component. That is, the Gaussian component can be greater than the Wiener component.

[0162]

[0163] If the following condition (3) is satisfied, the dominant component can be the Wiener component. That is, the Wiener component can be greater than the Gaussian component.

[0164]

[0165] If the following condition (4) is satisfied, there may be no dominant component. That is, the Wiener component can be substantially equal to the Gaussian component.

[0166]

[0167] When operating in the sub-THz band, RF damage may increase as a function of the band. The higher the band, the higher the RF damage can be. When transmitting PDCCH from the BS to the UE, RF damage can be considered to ensure robust and reliable reception at the UE.

[0168] Similarly, when operating in the sub-THz band, transmitter damage can increase as a function of the band. The higher the band, the higher the transmitter damage can be. When transmitting PDCCH from the BS to the UE, transmitter damage can be considered to ensure robust and reliable reception at the UE.

[0169] As described above, in traditional 5GS, the BS may not transmit a PDCCH including PT-RS or another reference signal (RS) with a definable configuration (for each resource element group (REG)). The BS may transmit a PDCCH including a demodulation reference signal (DMRS). Each control channel element (CCE) may include DMRS resource elements (RE). The DMRS has a fixed configuration for each REG. Phase noise can be equalized from the DMRS channel estimation.

[0170] When operating in the sub-THz band, RF damage at the UE can become significantly more challenging and highly dependent on the implementation. This means that the PDCCH framework used in traditional 5GS may not be efficient and reliable.

[0171] In 5G FR2-2 (52.6 - 71 GHz), NR Release 17 reuses most of the specifications from lower-frequency 5G FR2-1 because of the frequency increase and the very low time budget for the specifications.

[0172] In a traditional 5GS, PDCCH configurations can be defined in the frequency domain in a resource grid. The resource grid can include OFDM symbols. The PDCCH can include an aggregation level (AL). The AL can include a number of CCEs. There can be a direct relationship between the AL and the number of CCEs. That is, AL N can include N CCEs. Each CCE can include 6 REGs. Each REG can include 12 REs. The CCE-to-REG mapping can depend on the number of OFDM symbols occupied by the PDCCH. The number of OFDM symbols occupied by the PDCCH can be 1, 2, or 3, as Figure 8 in the example of

[0173] Figure 7 FIG. shows an example of a schematic representation of the CCE-to-REG mapping of the PDCCH in a traditional 5GS. Each column represents an OFDM symbol. Each cell represents a REG.

[0174] Figure 8 FIG. shows Table 7.3.2.1-1 of 3GPP TS 38.211, which specifies the relationship between the AL and the number of CCEs of the PDCCH in a traditional 5GS.

[0175] Figure 9 FIG. shows a table specifying the relationship between: the AL of the PDCCH in a traditional 5GS, the number of CCEs, the number of REGs, the number of PT-RS REs, the number of DMRS REs, the number of decoded control data (i.e., downlink control information (DCI)) REs, and the total number of bits for the decoded control data. Each control channel element (CCE) can include DMRS REs. The DMRS has a fixed configuration for each REG.

[0176] As Figure 9 illustrated, in a traditional 5GS, the BS does not transmit a PDCCH including PT-RS (i.e., the number of PT-RS REs is equal to zero). At most, the BS can transmit a PDSCH including PT-RS and / or the UE can transmit a PUSCH including PT-RS. One or more aspects of the present disclosure configure the BS to transmit a PDCCH including PT-RS.

[0177] When operating in a sub-THz band, a single-carrier waveform can be used to transmit the PDCCH to the UE. A (KT) DFT-S-OFDM system, an SC-FDE system, or an SC-TDE can be used to provide the single-carrier waveform. When using a single-carrier waveform, control data (i.e., DCI) symbols can be multiplexed with DMRS symbols in the time domain. The DMRS symbols can be used by the UE to perform frequency-domain channel estimation. The control data (i.e., DCI) symbols can be subject to PN changes experienced by the UE.

[0178] In a traditional 5GS, the BS may use a CP-OFDM system to transmit the Physical Downlink Shared Channel (PDSCH), and use a CP-OFDM system or a DFT-s-OFDM system to transmit the Physical Uplink Shared Channel (PUSCH). The PDSCH and PUSCH may include PT-RS.

[0179] For a CP-OFDM system, different PT-RS patterns may be defined in the frequency domain. For example, in a traditional 5GS, when transmitting the PDSCH or PUSCH, the PT-RS pattern may include a comb pattern distributed at different densities over the transmission bandwidth. In the future, the PT-RS pattern may also include a continuous pattern (also referred to as a block pattern), where the PT-RS is transmitted on multiple consecutive subcarriers. This may enable efficient ICI compensation at the UE. For a DFT-s-OFDM system, different PT-RS patterns may be defined in the time domain. These PT-RS patterns may improve PN mitigation at the receiver side.

[0180] Figure 10 Table 5.1.6.3-1 of TS 38.214 is shown, which defines different PT-RS patterns for the PUSCH using a CP-OFDM system in a traditional 5GS.

[0181] Figure 10 Table 5.1.6.3-2 of TS 38.214 is shown, which defines different PT-RS patterns for the PUSCH using a CP-OFDM system in a traditional 5GS.

[0182] Figure 11 Table 6.2.3.2-1 of TS 38.214 is shown, which defines different phase-tracking reference signal patterns for the PUSCH using a DFT-s-OFDM system in a traditional 5GS.

[0183] One or more aspects of the present disclosure provide a mechanism that allows the BS to define a PDCCH configuration based on a radio frequency (RF) impairment indication. The RF impairment indication may be determined by the UE and sent by the UE to the BS.

[0184] Alternatively or additionally, the RF impairment indication may be determined by the BS. For example, the RF impairment indication may be determined by the BS based on the frequency carrier and / or bandwidth used by the UE. For example, as the bandwidth used by the UE increases, the PN experienced by the UE also increases, especially at higher frequency carriers.

[0185] The RF damage indication can indicate the RF damage category. The RF damage indication can explicitly or implicitly indicate the RF damage category. That is, the RF damage indication can convey the RF damage category itself, or can convey information for deriving the RF damage category (as will be further apparent below). In an example, the RF damage categories include Category 1, Category 2, and Category 3.

[0186] It should be understood that the term "category" should be interpreted broadly and can be interchanged, for example, with the terms "level", "type", or "group". That is, the damage indication can explicitly indicate the damage level, damage type, or damage group.

[0187] The RF damage category can be assigned to the UE based on the severity of one or more RF damages. In an example, Category 1 refers to high RF damage(s), Category 2 refers to medium RF damage(s), and Category 3 refers to low RF damage(s).

[0188] The RF damage category can be assigned to the UE based on the dominant type of RF damage. In an example, Category 1 refers to PN damage, Category 2 refers to quantization damage, and Category 3 refers to in-phase and quadrature imbalance damage.

[0189] The RF damage category can be assigned to the UE based on the subtype of RF damage. In an example, Category 1 refers to the Wiener component being greater than the Gaussian component, Category 2 refers to the Gaussian component being greater than the Wiener component, and Category 3 refers to the Gaussian component being substantially equal to the Wiener component (i.e., the difference between the Gaussian component and the Wiener component is below a difference threshold).

[0190] In another example, Category 1 refers to the resolution of the analog-to-digital converter being lower than a threshold, Category 2 refers to the resolution of the analog-to-digital converter being substantially equal to the threshold, and Category 3 refers to the resolution of the analog-to-digital converter being greater than the threshold.

[0191] In another example, Category 1 refers to the in-phase and quadrature imbalance being lower than a threshold, Category 2 refers to the in-phase and quadrature imbalance being substantially equal to the threshold, and Category 3 refers to the in-phase and quadrature imbalance being greater than the threshold.

[0192] The larger the bandwidth assigned to the UE, the larger the Gaussian component can be compared to the Wiener component. The lower the bandwidth assigned to the user equipment, the larger the Wiener component can be compared to the Gaussian component.

[0193] As described above, the RF impairment indication can implicitly indicate the RF impairment category. That is, the BS can derive the RF impairment category from the RF impairment indication. The RF impairment indication can include an indication of a desired RS configuration. In other words, the RF impairment category can be implicitly indicated via the indication of the desired RS configuration. The desired RS configuration can include a desired PT-RS configuration and / or a desired DMRS configuration. The BS can derive the RF impairment category assigned to the UE based on the indication of the desired RS configuration.

[0194] In another example, the RF impairment indication can include the quality of the local oscillator at the UE. In other words, the RF impairment category can be implicitly indicated via the quality of the local oscillator at the UE. The BS can derive the RF impairment category assigned to the UE based on the quality of the local oscillator at the UE.

[0195] In another example, the RF impairment indication can include the resolution of the analog-to-digital converter at the UE. In other words, the RF impairment category can be implicitly indicated via the resolution of the analog-to-digital converter at the UE. The BS can derive the RF impairment category assigned to the UE based on the resolution of the analog-to-digital converter at the UE.

[0196] In another example, the RF impairment indication can include the physical random access channel preamble used by the UE in the initial access phase. In other words, the RF impairment category can be implicitly indicated via the physical random access channel preamble used by the UE in the initial access phase. The BS can derive the RF impairment category assigned to the UE based on the physical random access channel preamble used by the UE in the initial access phase.

[0197] It should be understood that the RF impairment category can be implicitly indicated in various ways, for example, by using a specific PRACH configuration (preamble / format / sequence length / preamble repetition count / ...), by sending a UE request for a specific configuration (RS density / mode, AL,...), by generally binding some RF impairments to a specific configuration (e.g., MIMO in sub-THz -> low ADC, wideband at high carrier frequency -> high PN,...), by indicating UE capabilities and / or the level / range of one or more RF impairments and / or the dominant RF impairment type / subtype. All these indications can implicitly imply a specific RF impairment category that requires a specific configuration.

[0198] The RF impairment indication can be specific to at least one of the bandwidth, SCS, or frequency carrier used by the UE. That is, the BS can receive an RF impairment indication for the bandwidth or SCS and / or frequency carrier used by the UE and another RF impairment indication for another bandwidth or another SCS and / or frequency carrier used by the UE.

[0199] The BS can define the PDCCH configuration based on RF damage indication. The BS can define the PDCCH configuration within the PDCCH search space. The PDCCH search space can be known to the UE.

[0200] Defining the PDCCH configuration can include defining at least one of CCE configuration, RS configuration, SCS configuration, AL configuration, REG configuration, REG bundling configuration, modulation scheme (MCS) configuration, or code rate configuration.

[0201] Defining the CCE configuration can include defining the CCE configuration for each block or multiple blocks. Defining the CCE configuration can include defining the number of REGs for each CCE. Defining the CCE configuration can include defining the CCE mode. Defining the mode can include defining a partially continuous mode in which the CCEs are transmitted on consecutive blocks or a partially discontinuous mode in which the CCEs are transmitted on non-consecutive blocks. The mode can be partially continuous and partially discontinuous, i.e., some CCEs can be transmitted on consecutive blocks and other CCEs can be transmitted on non-consecutive blocks.

[0202] A block can transmit a set of modulation symbols, and the set of modulation symbols can be prefixed with a cyclic prefix and sent to the UE in the time domain, as Figures 4 to 6 shown. Each modulation symbol can be transmitted by a set of samples. The block can be a (KT) DFT-s-OFDM block, SC-FDE block, SC-TDE block, or CP-OFDM block. The cyclic prefix can include a determined pattern. The cyclic prefix can include a unique word, zero padding, or others.

[0203] Figure 12 Shows different CCE configurations when transmitting the PDCCH using a single-carrier waveform provided by a (KT) DFT-s-OFDM system, SC-FDE system, or SC-TDE system. In the first configuration, a single CCE can be transmitted throughout the block. In the second configuration, a single CCE can be transmitted in a part of the block. The PDSCH can be transmitted in another part of the block. In the third configuration, multiple CCEs can be transmitted throughout the block. In the first, second, and third configurations, a single CCE can be extended over a single OFDM symbol or multiple OFDM symbols.

[0204] Defining the RS configuration can include defining the PT-RS configuration and / or defining the DMRS configuration.

[0205] Defining the RS configuration can include defining the RS configuration for each CCE, each multiple CCEs, each REG, each multiple REGs, each block, or each multiple blocks.

[0206] Defining the RS configuration may include defining the number of RS symbols. The RS symbols may represent known modulation symbols. Defining the number of RS symbols may include defining the number of RS symbols in the time domain (i.e., time density) or the number of RS symbols in the frequency domain (i.e., frequency density).

[0207] Defining the RS configuration may include defining the pattern of RS symbols. Defining the pattern of RS symbols may include defining the pattern of RS symbols on a single or multiple OFDM or single carrier symbols or blocks. Defining the pattern of RS symbols may include defining a continuous pattern, where the RS symbols span multiple consecutive blocks. Defining the pattern of RS symbols may include defining a discontinuous pattern, where the reference signal symbols span multiple non - consecutive blocks. The pattern may be partially continuous and partially discontinuous, i.e., some RS symbols may be transmitted on consecutive blocks and other RS symbols may be transmitted on non - consecutive blocks.

[0208] Defining the RS configuration may include defining the transmission power of RS symbols.

[0209] Defining the RS configuration may be based on the AL used for the PDCCH. The lower the AL, the higher the overhead of RS symbols may be (if the coding rate increases as the AL decreases). The lower the AL, the higher the transmission power of RS symbols may be.

[0210] Defining the RS configuration may be based on the coding rate used for the PDCCH. The higher the coding rate, the higher the number of RS symbols may be.

[0211] Defining the RS configuration may be based on the modulation scheme used for the PDCCH. The higher the modulation scheme, the higher the overhead of RS symbols may be.

[0212] Defining the RS configuration may be based on the waveform used to send the PDCCH to the UE. That is, when the BS uses a single - carrier waveform to send the PDCCH to the UE, the BS may define the RS configuration, and when the BS uses a multi - carrier waveform to send the PDCCH to the UE, the BS may define another RS configuration.

[0213] Defining the PDCCH configuration may include defining the SCS configuration. It should be understood that defining the SCS configuration applies to CP - OFDM systems and (KT) DFT - s - OFDM systems, but not to SC - FDE systems.

[0214] Defining the PDCCH configuration may include defining the coding rate. The coding rate may be adjusted based on the PT - RS configuration.

[0215] Figure 13An example table showing the following items is presented: the relationship between the AL level, the number of CCEs, the number of REGs, the number of REs, the number of PT-RS REs, the number of DMRS REs, the number of REs for the control data (i.e., DCI) for warp decoding, and the total number of bits for the control data (i.e., DCI) for warp decoding.

[0216] The BS can transmit the PDCCH based on the PDCCH configuration. The BS can use a single-carrier waveform or a multi-carrier waveform. The single-carrier waveform can be provided by a (KT) DFT-s-OFDM system, an SC-FDE system, or an SC-TDE system. The multi-carrier waveform can be provided by a CP-OFDM waveform.

[0217] The BS can determine the PDCCH configuration based on the RF impairment indication. The UE can receive the PDCCH configuration from the BS or generally from the network (e.g., in a system information block or dedicated RRC signaling or other signaling methods). Alternatively, the UE can determine the PDCCH configuration based on the RF impairment indication. The UE can receive the PDCCH from the BS using the PDCCH configuration determined based on the RF impairment indication.

[0218] The above aspects can be combined in all possible ways to design all possible implementations. Only a few implementations are discussed as examples.

[0219] In an implementation, when the RF impairment indication indicates a certain RF impairment category, the BS can define the DMRS configuration such that the DMRS symbols are transmitted in multiple blocks, and the number of DMRS symbols per CCE, per REG, or per block is greater than a number threshold. In this way, the channel can be reliably estimated.

[0220] In an implementation, when the RF impairment indication indicates a certain RF impairment category, the BS can define the minimum SCS, the DMRS mode, and the PT-RS mode.

[0221] In an implementation, when the RF impairment indication indicates a certain RF impairment category, the BS can define the DMRS mode and the PT-RS mode.

[0222] In an implementation, when the RF impairment indication indicates a certain RF impairment category, the BS can define the PT-RS configuration such that the number of PT-RS symbols per CCE, per REG, or per block is greater than a number threshold.

[0223] In an implementation, when the RF impairment indication indicates a certain RF impairment category, each CCE can include 18 DMRS REs. Each CCE can be transmitted in two blocks. Each CCE can include 12 REGs.

[0224] In an implementation, when an RF impairment indication indicates a certain RF impairment, each PTRS pattern can be transmitted on multiple CCEs or multiple REGs. In this implementation, the UE can jointly optimize phase noise from the PTRS symbols on multiple CCEs or REGs.

[0225] Figure 14 Different PT-RS configurations based on the category associated with the UE are shown. Each row can represent one or more time-domain single-carrier symbols (e.g., DFT-s-OFDM symbols or KT-DFT-s-OFDM symbols), time-domain blocks, CCEs, or REGs. In this example figure, each row represents, for example, a CCE or REG in the upper half figure or multiple CCEs or REGs in the lower half figure, and a row can be referred to as a block in both figures. The block can transmit one or more CCEs including PT-RS symbols (shaded units). When the UE is associated with category 1, category 2, or category 3, the number of PT-RS symbols per CCE can be the same. That is, when the UE is associated with category 1, category 2, or category 3, the PT-RS overhead per CCE is the same. Alternatively, when the UE is associated with category 1, category 2, or category 3, the number of PT-RS symbols per CCE can be different. That is, when the UE is associated with category 1, category 2, or category 3, the PT-RS overhead per CCE is different.

[0226] When the UE is associated with category 1, the BS can define a PT-RS configuration having a first mode and a first number of PT-RS symbols. The first mode can include a discontinuous mode, where the PT-RS symbols can be transmitted on discontinuous blocks.

[0227] When the UE is associated with category 2, the BS can define a PT-RS configuration having a second mode and a second number of PT-RS symbols. The second mode can include a partially continuous / partially discontinuous mode, where some PT-RS symbols can be transmitted on continuous blocks and some PT-RS symbols can be transmitted on discontinuous blocks. The second number of PT-RS symbols can be the same as or lower than the first number of PT-RS symbols.

[0228] When the UE is associated with category 3, the BS can define a PT-RS configuration having a third mode and a third number of PT-RS symbols. The third mode can include a partially continuous / partially discontinuous mode, where some PT-RS symbols can be transmitted on continuous blocks and some PT-RS symbols can be transmitted on discontinuous blocks. The third number of PT-RS symbols can be the same as or lower than the second number of PT-RS symbols.

[0229] Figure 15Shows different PT-RS configurations based on the category associated with the UE. When the UE is associated with Category 1, Category 2, or Category 3, the number of PT-RS symbols per CCE can be different. That is, when the UE is associated with Category 1, Category 2, or Category 3, the PT-RS overhead per CCE is different.

[0230] When the UE is associated with Category 1 and the first code rate, the BS can define a PT-RS configuration with a first number of PT-RS symbols per CCE. When the UE is associated with Category 2, the BS can define a PT-RS configuration with a second number of PT-RS symbols per CCE and a second code rate. When the UE is associated with Category 3, the BS can define a PT-RS configuration with a third number of PT-RS symbols per CCE and a third code rate. The first number of PT-RS symbols per CCE can be greater than the second number of PT-RS symbols per CCE. The second number of PT-RS symbols per CCE can be greater than the third number of PT-RS symbols per CCE. The first code rate can be greater than the second code rate. The second code rate can be greater than the third code rate.

[0231] It should be understood that in Figure 15 the last column is the number of bits of data available for warp decoding. However, if the same amount of actual information is to be transmitted in different scenarios, then in the case of using more PT-RS symbols, the coding / decoding rate may have to be greater.

[0232] Figure 16 Shows an example PT-RS and DMRS configuration for a CCE that occupies two OFDM symbols. Each column can represent an OFDM symbol. Each cell can represent a RE. Each CCE can be conveyed on two consecutive blocks. Each CCE can include DMRS symbols transmitted on the first block. Each CCE can include coded / decoded control data (i.e., DCI) symbols transmitted on the second block. Each CCE can include PT-RS transmitted on the second block. The PT-RS configuration can depend on the RF impairment indication received from the UE. The PT-RS configuration can depend on the SCS used by the UE.

[0233] On the left-hand side, a first example CCE including a DMRS configuration according to a conventional system is illustrated, where the DM-RS symbols can be transmitted in a distributed manner in a single OFDM symbol. According to an embodiment, the DM-RS (or alternatively PT-RS) configuration can depend on the RF impairment and can enable efficient PN compensation for certain UEs.

[0234] A second example of a CCE defined over two OFDM symbols involving a PT-RS configuration with corresponding optimizations on the CCE is illustrated on the right hand side, where the DMRS symbol occupies the first OFDM symbol of the CCE and the PT-RS symbol can be transmitted in the second OFDM symbol of the CCE (e.g., in a block-by-block manner in this example). Similarly, these configurations can depend on RF impairments, and control data can also be included in the first block. In the example, the CCE can also be replaced by a REG, a certain number of REGs, or a certain number of CCEs.

[0235] In an implementation, when the RF impairment indication indicates a certain RF impairment category, the CCE configuration can be the same as in conventional 5GS, but the DMRS configuration and the coding rate configuration can be different. The number of DMRS symbols can be increased. The coding rate of the control data (i.e., DCI) for channel encoding and decoding can be increased or decreased.

[0236] In an implementation, when the RF impairment indication indicates a certain RF impairment category, each CCE can be transmitted by a single block. The number of PT-RS symbols can be increased. The coding rate of the control data (i.e., DCI) for channel encoding and decoding can be increased or decreased.

[0237] In an implementation, when the RF impairment indication indicates a certain RF impairment category, each CCE can be transmitted in a single block. The number of DMRS symbols can be increased. The coding rate of the control data (i.e., DCI) for channel encoding and decoding can be increased or decreased.

[0238] In an implementation, when the RF impairment indication indicates a certain RF impairment category, each CCE can be transmitted in two blocks. The DMRS symbol can be transmitted in the first block. The PT-RS symbol and the control data (i.e., DCI) symbol can be transmitted in the second block. The coding rate for the control data can remain unchanged.

[0239] In an implementation, when the RF impairment indication indicates a certain RF impairment category, each CCE can be transmitted in two or more blocks. The DMRS symbol can be transmitted in a block. The PT-RS symbol and the control data (i.e., DCI) symbol can be conveyed in the same block or another block. The coding rate for the control data can be increased or decreased.

[0240] One or more aspects of the present disclosure are advantageous because they allow a UE experiencing various RF impairments to reliably receive a PDCCH transmitted from a BS.

[0241] Figure 17 A block diagram of a method for receiving a PDCCH performed by a UE is shown.

[0242] In step 1700, the UE may send an RF impairment indication to a network node.

[0243] In step 1702, the UE may receive from the network node a PDCCH having (i.e., configured with) a PDCCH configuration determined based on the RF impairment indication.

[0244] The UE may monitor the PDCCH having a PDCCH configuration determined based on the RF impairment indication. Alternatively, the UE may blindly monitor a PDCCH having a different PDCCH configuration.

[0245] The network node may be a BS.

[0246] The RF impairment indication may explicitly indicate an RF impairment category.

[0247] The RF impairment indication may depend on the severity of the RF impairment. The severity of the RF impairment at the UE may include at least one of the following: high RF impairment; medium RF impairment; or low RF impairment.

[0248] The RF impairment indication may depend on the type of the RF impairment. The type of the RF impairment at the UE may include at least one of the following: phase noise impairment; quantization impairment; in-phase and quadrature imbalance impairment; power amplifier non-linearity, time jitter; or carrier frequency offset.

[0249] The RF impairment indication may depend on the subtype of the RF impairment at the UE.

[0250] The RF impairment indication may implicitly indicate the RF impairment category assigned to the UE. The RF impairment indication may include at least one of the following: the desired RS configuration of the UE; the quality of the local oscillator at the UE; the resolution of the analog-to-digital converter at the UE; or the PRACH preamble used by the UE in the initial access phase.

[0251] The RF impairment indication may be sent via at least one of the following: capability information signaling; physical random access channel signaling; or radio resource control signaling.

[0252] The desired reference signal configuration may include the desired PT-RS configuration.

[0253] The RF impairment indication may be specific to at least one of the bandwidth, SCS, or frequency carrier used by the UE.

[0254] The determination of the PDCCH configuration by the UE may include determining at least one of the following: RS configuration; SCS interval configuration; AL configuration; CCE configuration; REG configuration; REG bundle configuration; MCS configuration; or code rate configuration.

[0255] The RS configuration may include the number of RS symbols.

[0256] Determining the RS configuration may include determining at least one of the following: the pattern of RS symbols; or the transmission power of RS symbols.

[0257] Determining the pattern of RS symbols may include: determining a continuous pattern, where the RS symbols span multiple consecutive blocks; or determining a discontinuous pattern, where the RS symbols span multiple non - consecutive blocks.

[0258] Determining the RS configuration may include determining the RS configuration on at least one of the following: a CCE or multiple CCEs; a REG or multiple REGs; or a block or multiple blocks.

[0259] Determining the RS configuration may include determining at least one of the following: the PT - RS configuration; or the DMRS configuration.

[0260] Determining the RS configuration may be based on at least one of the following: the AL used by the UE; the coding and decoding rate used by the UE; or the waveform used by the UE for transmitting the PDCCH.

[0261] The lower the AL, the higher the overhead of RS symbols can be (if the coding and decoding rate increases as the AL decreases).

[0262] The lower the AL, the higher the transmission power of RS symbols can be.

[0263] The waveform for transmitting the PDCCH may include a single - carrier waveform or a multi - carrier waveform.

[0264] The single - carrier waveform may be provided by at least one of the following: a DFT - s - OFDM system; a (KT)DFT - S - OFDM system; an SC - FDE system or an SC - TDE system.

[0265] The multi - carrier waveform may be provided by a CP - OFDM system.

[0266] Determining the AL configuration may include determining the minimum AL.

[0267] The higher the coding and decoding rate (i.e., the lower the AL), the more harmful the RF impairments are. Therefore, the AL may be equal to or greater than the minimum AL to mitigate RF impairments.

[0268] The PDCCH configuration may be determined by the UE based on the RF impairment indication; or the PDCCH configuration may be determined by the network node based on the RF impairment indication and received by the UE from the network node.

[0269] Figure 18 A block diagram of a method for transmitting a PDCCH performed by a network node is shown.

[0270] In step 1800, the network node may receive an RF impairment indication from the UE.

[0271] In step 1802, the network node may determine the PDCCH configuration based on the RF impairment indication.

[0272] In step 1804, the network node may send a PDCCH with (i.e., configured with) the PDCCH configuration to the UE.

[0273] Figure 19 A schematic representation of a non - volatile memory medium 1900 storing instructions and / or parameters which, when executed by a processor, allow the processor to perform Figure 17 and 18 one or more steps of the method.

[0274] Note that although the above describes example embodiments, several variations and modifications can be made to the disclosed solutions without departing from the scope of the present invention.

[0275] It should be understood that although the above concepts have been discussed in the context of 5GS, one or more of these concepts may be applied to other cellular systems.

[0276] Thus, embodiments may vary within the scope of the appended claims. Generally, some embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. For example, some aspects may be implemented in hardware while other aspects may be implemented in firmware or software executable by a controller, microprocessor, or other computing device, but the embodiments are not limited thereto. Although various embodiments may be shown and described as block diagrams, flowcharts, or using some other graphical representation, it is well understood that, as a non - limiting example, the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or a controller or other computing device, or some combination thereof.

[0277] Embodiments may be implemented by computer software stored in a memory and executable by at least one data processor of the entities involved, or by hardware, or by a combination of software and hardware. Further, in this regard, it should be noted that any process (e.g., as Figure 17 and Figure 18 shown) may represent program steps, or interconnected logic circuits, blocks, and functions, or a combination of program steps and logic circuits, blocks, and functions. The software may be stored on physical media such as memory chips or memory blocks implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media such as DVDs and their data variants, CDs.

[0278] The memory can be of any type suitable for the local technical environment and can be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. As a non-limiting example, the data processor can be of any type suitable for the local technical environment and can include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), gate-level circuitry, and a processor based on a multi-core processor architecture.

[0279] Alternatively or additionally, some embodiments can be implemented using circuitry. The circuitry can be configured to perform one or more of the previously described functions and / or method steps. The circuitry can be provided in a base station and / or a communication device.

[0280] As used in this application, the term "circuitry" can refer to one or more or all of the following:

[0281] (a) Implementations using only hardware circuitry (such as implementations in only analog and / or digital circuitry) and

[0282] (b) Combinations of hardware circuitry and software, such as:

[0283] (i) Combinations of analog and / or digital hardware circuitry with software / firmware; and

[0284] (ii) Any portion of a hardware processor, software, and memory with software (including a digital signal processor) that work together to cause a device (such as a communication device or a base station) to perform the various functions previously described, and

[0285] (c) Hardware circuitry and / or a processor, such as a microprocessor or a portion of a microprocessor, that requires software (such as firmware) to operate but may not have the software present when not required to operate.

[0286] This definition of circuitry applies to all uses of the term in this application (including any claims). As another example, as used in this application, the term circuitry also covers implementations of only hardware circuitry or a processor (or processors) or a portion of hardware circuitry or a processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example, integrated devices.

[0287] However, various modifications and alterations will become apparent to those skilled in the relevant art upon reading the foregoing description in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings will still fall within the scope configured by the appended claims.

Claims

1. A device, comprising at least one processor and at least one memory, the at least one memory including computer code for one or more programs, the at least one memory and the computer code being configured to cause the device, using the at least one processor, to at least: Send a radio frequency impairment indication to a network node; and Receive, from the network node, a physical downlink control channel having a physical downlink control channel configuration that is determined based on the radio frequency impairment indication.

2. The device according to claim 1, wherein the radio frequency impairment indication explicitly indicates a radio frequency impairment class.

3. The device according to claim 2, wherein the radio frequency impairment indication depends on the severity of the radio frequency impairment.

4. The device according to claim 3, wherein the severity of the radio frequency impairment at the device includes at least one of the following: High radio frequency impairment; Medium radio frequency impairment; or Low radio frequency impairment.

5. The device according to any one of claims 2 to 4, wherein the radio frequency impairment indication depends on the type of the radio frequency impairment.

6. The device according to claim 5, wherein the type of the radio frequency impairment at the device includes at least one of the following: Phase noise impairment; Quantization impairment; In-phase and quadrature imbalance impairment; Power amplifier non-linearity, Time jitter; or Carrier frequency offset.

7. The device according to claim 5 or claim 6, wherein the radio frequency impairment indication depends on a subtype of the radio frequency impairment at the device.

8. The device according to claim 1, wherein the radio frequency impairment indication implicitly indicates a radio frequency impairment class assigned to the device.

9. The device according to claim 8, wherein the radio frequency impairment indication includes at least one of the following: The desired reference signal configuration of the device; The quality of the local oscillator at the device; The resolution of the analog-to-digital converter at the device; or The physical random access channel preamble used by the device in an initial access phase.

10. The device according to any one of claims 1 to 9, wherein the radio frequency impairment indication is specific to at least one of the bandwidth, subcarrier spacing, or frequency carrier used by the user equipment.

11. The device according to any one of claims 1 to 10, wherein determining the physical downlink control channel configuration by the device includes determining at least one of the following: Reference signal configuration; Subcarrier spacing configuration; Aggregation level configuration; Control channel element configuration; Resource element group configuration; Resource element group bundling configuration; Modulation scheme configuration; or Code rate configuration.

12. The device according to claim 11, wherein the reference signal configuration includes the number of reference signal symbols.

13. The device according to claim 11 or claim 12, wherein determining the reference signal configuration includes determining at least one of the following: The pattern of the reference signal symbols; or The transmission power of the reference signal symbols.

14. The device according to claim 13, wherein determining the pattern of the reference signal symbols includes: Determining a continuous pattern, wherein the reference signal symbols span multiple consecutive blocks; Or Determine a discontinuous pattern, wherein the reference signal symbols span multiple discontinuous blocks.

15. The apparatus according to any one of claims 11 to 14, wherein determining the reference signal configuration comprises determining the reference signal configuration on at least one of: A control channel element or a plurality of control channel elements; A resource element group or a plurality of resource element groups; or A block or a plurality of blocks.

16. The apparatus according to any one of claims 11 to 15, wherein determining the reference signal configuration comprises determining at least one of: A phase-tracking reference signal configuration; or A demodulation reference signal configuration.

17. The apparatus according to any one of claims 11 to 16, wherein determining the reference signal configuration is based on at least one of: The aggregation level used by the apparatus; The coding rate used by the apparatus; or The waveform used by the apparatus for transmitting the physical downlink control channel.

18. The apparatus according to any one of claims 11 to 17, wherein determining the aggregation level configuration comprises determining a minimum aggregation level.

19. The apparatus according to any one of claims 1 to 18, wherein the physical downlink control channel configuration is determined by the apparatus based on the radio frequency impairment indication; or wherein the physical downlink control channel configuration is determined by the network node based on the radio frequency impairment indication and received by the apparatus from the network node.

20. An apparatus comprising at least one processor and at least one memory, the at least one memory comprising computer code for one or more programs, the at least one memory and the computer code being configured to, using the at least one processor, cause the apparatus to at least: Receive a radio frequency impairment indication from a user equipment; Determine a physical downlink control channel configuration based on the radio frequency impairment indication; and Transmit a physical downlink control channel having the physical downlink control channel configuration to the user equipment.

21. A method, comprising: Transmitting a radio frequency impairment indication to a network node; and Receiving from the network node a physical downlink control channel having a physical downlink control channel configuration determined based on the radio frequency impairment indication.

22. A method, comprising: Receiving a radio frequency impairment indication from a user equipment; Determining a physical downlink control channel configuration based on the radio frequency impairment indication; and Transmitting to the user equipment the physical downlink control channel having the physical downlink control channel configuration.

23. A computer program comprising computer-executable instructions which, when run on one or more processors, perform the steps of the method according to claim 21 or claim 22.

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