Transmission structure and format of downlink control channel

Abstract

A method for receiving a physical downlink control channel (PDCCH) by a user equipment (UE) is provided. The UE receives configuration information for a first control resource set including a certain number of symbols in a time domain and a certain number of resource blocks (RBs) in a frequency domain, the configuration information indicating a first number N bundle,1 The frequency of continuous RBs, and N bundle,1 The UE assumes that the demodulation reference signal associated with the reception of the PDCCH is in the first control resource set in a certain number of frequency distribution blocks of N RBs. bundle,1 The invention also provides a method for constructing a search space to reduce the number of channel estimations performed by a UE for decoding a PDCCH relative to a conventional search space.

Description

[0001] This application is a divisional application of the invention patent application with application date of February 6, 2018 and application number 201880010486.3. Technical Field

[0002] The present application relates generally to control channel operation in wireless communication systems. More specifically, the present disclosure relates to transmission structures and formats in wireless communication systems. Background Art

[0003] The development of the fifth generation (5G) mobile communications (initial commercialization is expected around 2020) has been gaining momentum recently with worldwide technical activities on various candidate technologies from industry and academia. Candidate enablers for 5G mobile communications include massive antenna technology (from traditional cellular bands to high frequencies) to provide beamforming gain and support increased capacity, new waveforms (e.g., new radio access technology (RAT)) to flexibly adapt to various services / applications with different requirements, new multiple access schemes to support large-scale connections, etc. The International Telecommunication Union (ITU) has classified the use scenarios of international mobile telecommunication (IMT) in 2020 and beyond into three categories, such as enhanced mobile broadband, massive machine type communication (MTC), and ultra-reliable and low-latency communication. In addition, the ITC has set target requirements such as a peak data rate of 20 Gigabits per second (Gb / s), a user-experienced data rate of 100 Megabits per second (Mb / s), a 3x improvement in spectral efficiency, support for mobility up to 500 kilometers per hour (km / h), 1 millisecond (ms) latency, a connection density of 106 devices / square kilometer, a 100x improvement in network energy efficiency, and an area traffic capacity of 10Mb / s / m 2 . Summary of the invention

[0004] Technical issues

[0005] While not all requirements need to be met simultaneously, 5G network design can provide use-case-based flexibility to support a variety of applications that meet some of the above requirements.

[0006] Technical Solution

[0007] In one embodiment, a method for receiving a physical downlink control channel (PDCCH) by a user equipment (UE) is provided. The method includes receiving configuration information for a first set of control resources including a certain number of symbols in the time domain and a certain number of resource blocks (RBs) in the frequency domain. The method also includes receiving a first number N indicating bundle,1 The method further includes receiving at N bundle,1 The UE assumes that the demodulation reference signal associated with the reception of the first PDCCH is in the control resource set of a certain number of frequency distribution blocks of N RBs. bundle,1 The same precoding is used on each RB.

[0008] In another embodiment, a user equipment (UE) includes a receiver configured to receive configuration information for a first set of control resources including a certain number of symbols in the time domain and a certain number of resource blocks (RBs) in the frequency domain. The receiver is also configured to receive an indication of the first number N bundle,1 The receiver is further configured to receive the configuration information of the frequency-contiguous RBs in N bundle,1 The receiver assumes that the demodulation reference signal associated with the PDCCH reception is in the range of N bundle,1 The same precoding is used on each RB.

[0009] In yet another embodiment, the base station includes a transmitter configured to transmit configuration information for a first set of control resources including a certain number of symbols in the time domain and a certain number of resource blocks (RBs) in the frequency domain. The transmitter is further configured to transmit an indication of the first number N bundle,1 The transmitter is additionally configured to bundle,1 The physical downlink control channel (PDCCH) is transmitted in a control resource set in a certain number of frequency distribution blocks of RBs. The demodulation reference signal associated with the transmission of the PDCCH is in N bundle,1 The same precoding is used on each RB.

[0010] Other technical features may be apparent to one skilled in the art from the following drawings, description and claims.

[0011] Before the following detailed description, it may be advantageous to set forth the definitions of certain words and phrases used throughout this patent document. The term "coupling" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not these elements are in physical contact with each other. The terms "send", "receive" and "communication" and their derivatives cover both direct and indirect communication. The terms "include" and "comprise" and their derivatives refer to including but not limited to. The term "or" is inclusive, referring to and / or. The phrase "associated with..." and its derivatives refer to including, including, interconnected with, including, included, connected to or with... connected, coupled to or with... coupled, with... communicable, with... cooperation, interweaving, parallel, close to, coupled to or with... combined, having, having the nature of..., with... related to or with... having a relationship, etc. The term "controller" refers to any device, system or part thereof that controls at least one operation. Such a controller can be implemented with hardware or a combination of hardware and software and / or firmware. The functions associated with any particular controller can be centralized or distributed, whether local or remote. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one of the items in the list may be needed. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0012] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data, or a part thereof suitable for implementation in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. "Non-transitory" computer-readable media does not include wired, wireless, optical, or other communication links that transmit temporary electrical signals or other signals. Non-transitory computer-readable media include media in which data can be permanently stored and media in which data can be stored and subsequently rewritten, such as rewritable optical discs or erasable memory devices.

[0013] Definitions for certain other words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior and future uses of such defined words and phrases.

[0014] Advantageous Effects of the Invention

[0015] The present disclosure relates to pre-fifth generation (5G) or 5G communication systems that will be provided to support higher data rates beyond fourth generation (4th-Generation, 4G) communication systems such as long term evolution (LTE). Embodiments of the present disclosure provide transmission structures and formats in advanced communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like parts:

[0017] Figure 1 An example wireless network according to an embodiment of the present disclosure is shown;

[0018] Figure 2 An example eNB according to an embodiment of the present disclosure is shown;

[0019] Figure 3 An example UE according to an embodiment of the present disclosure is shown;

[0020] Figure 4 An example DL slot structure for PDSCH transmission or PDCCH transmission according to an embodiment of the present disclosure is shown;

[0021] Figure 5 An example UL slot structure for PUSCH transmission or PUCCH transmission according to an embodiment of the present disclosure is shown;

[0022] Figure 6 An example hybrid slot structure for DL ​​transmission and UL transmission according to an embodiment of the present disclosure is shown;

[0023] Figure 7 An example transmitter structure using OFDM according to an embodiment of the present disclosure is shown;

[0024] Figure 8 An example receiver structure using OFDM according to an embodiment of the present disclosure is shown;

[0025] Fig. 9 An example encoding process of a DCI format according to an embodiment of the present disclosure is shown;

[0026] Fig.10An example decoding process of a DCI format for use by a UE according to an embodiment of the present disclosure is shown;

[0027] Fig.11 An example distributed PDCCH transmission structure depending on various CCE aggregation levels according to an embodiment of the present disclosure is shown;

[0028] Fig.12 An example centralized PDCCH transmission structure depending on various CCE aggregation levels according to an embodiment of the present disclosure is shown;

[0029] Fig.13 shows an example PDCCH transmission and PDSCH transmission demodulated using the same DMRS according to an embodiment of the present disclosure;

[0030] Fig.14 An example operation of a UE assuming the same DMRS precoding in a predetermined time slot and a predetermined RB of a DL control resource set according to an embodiment of the present disclosure is shown;

[0031] Fig.15 An example operation of a DCI format including a binary flag to indicate a transmission scheme among multiple transmission schemes for PDSCH transmission or PUSCH transmission according to an embodiment of the present disclosure is shown;

[0032] Fig.16 An example nested structure of PDCCH candidates according to an embodiment of the present disclosure is shown;

[0033] Fig.17 An example process of determining CCEs for PDCCH candidates based on a first implementation of a nested PDCCH search space structure according to an embodiment of the present disclosure is shown;

[0034] Fig.18 An example determination of CCEs for PDCCH candidates based on a first method of a first implementation of a nested PDCCH search space structure according to an embodiment of the present disclosure is shown;

[0035] Fig.19 An example determination of CCEs for PDCCH candidates based on a second implementation according to an embodiment of the present disclosure is shown;

[0036] Fig. 20 An example CCE index of a PDCCH candidate based on a second implementation manner according to an embodiment of the present disclosure is shown;

[0037] Fig.21 An example control resource subset in a control resource set according to an embodiment of the present disclosure is shown;

[0038] Fig. 22shows example CCE indices for PDCCH candidates spanning one or two OFDM symbols in a nested structure according to an embodiment of the present disclosure;

[0039] Fig.23 An example nested allocation of CCE indices to PDCCH candidates based on an ascending order of PDCCH candidates according to an embodiment of the present disclosure is shown;

[0040] Fig.24 An example nested allocation of CCE indices to PDCCH candidates based on a restriction on CCE indices of a certain number of PDCCH candidates according to an embodiment of the present disclosure is shown;

[0041] Fig.25 shows example CSI-RS transmissions in a number of NBs according to an embodiment of the present disclosure, wherein the UE re-tunes to the NB for which the UE is configured for PDCCH reception after receiving the CSI-RS transmission;

[0042] Fig.26 An example CSI-RS transmission in a number of NBs according to an embodiment of the present disclosure is shown, wherein the UE re-tunes to each NB configured to receive CSI-RS transmission before re-tuning to a NB configured for PDCCH reception;

[0043] Fig. 27 An example content of a DCI format with a CRC scrambled by a CSI-RS-RNTI is shown, which triggers CSI-RS transmission in a subset of NBs in a set of NBs for one or more UEs according to an embodiment of the present disclosure;

[0044] Fig.28 An example content of a DCI format with a CRC scrambled by a CSI-RS-RNTI is shown, which triggers CSI-RS transmission in a subset of NBs in a set of NBs for one or more UEs, and provides PUCCH resources and TPC commands for transmission of CSI reports according to an embodiment of the present disclosure;

[0045] Fig.29 An example PUCCH resource determination for a UE to send a PUCCH conveying a CSI report based on the PUCCH resources indicated in a DCI format triggering CSI-RS transmission according to an embodiment of the present disclosure is shown; and

[0046] Fig.30 It shows a frequency hopping pattern of a NB in ​​which a UE is configured to receive a PDCCH according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0047] Discussed below Figures 1 to 30, and the various embodiments used in this patent document to describe the principles of the present disclosure are merely exemplary and should not be interpreted in any way to limit the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0048] The following documents are incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 36.211 v14.1.0, "E-UTRA, Physical Channels and Modulation"; 3GPP TS 36.212 v14.1.0, "E-UTRA, Multiplexing and Channel Coding"; 3GPP TS 36.213 v14.1.0, "E-UTRA, Physical Layer Procedures"; 3GPP TS 36.321 v14.1.0, "E-UTRA, Medium Access Control (MAC) Protocol Specification", and 3GPP TS 36.331 v14.1.0, "E-UTRA, Radio Resource Control (RRC) Protocol Specification".

[0049] The following Figure 1-Figure 3 Various embodiments are described for implementation in wireless communication systems using orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication techniques. Figure 1-Figure 3 The description is not meant to imply physical or architectural limitations to the manner in which different embodiments may be implemented. Different embodiments of the present disclosure may be implemented in any suitably arranged communications system.

[0050] Figure 1 An exemplary wireless network according to an embodiment of the present disclosure is shown. Figure 1 The embodiment of the wireless network shown is for illustration only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present disclosure.

[0051] like Figure 1 As shown, the wireless network includes eNB 101, eNB 102, and eNB 103. eNB 101 communicates with eNB 102 and eNB 103. eNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0052] The eNB 102 provides wireless broadband access to a network 130 for a first plurality of user equipments (UEs) within a coverage area 120 of the eNB 102. The first plurality of UEs includes a UE 111, which may be located in a small business (SB); a UE 112, which may be located in an enterprise (E); a UE 113, which may be located in a WiFi hotspot (HS); a UE 114, which may be located in a first residence (R); a UE 115, which may be located in a second residence (R); and a UE 116, which may be a mobile device (M), such as a cellular phone, a wireless laptop, a wireless PDA, etc. The eNB 103 provides wireless broadband access to a network 130 for a second plurality of UEs within a coverage area 125 of the eNB 103. The second plurality of UEs includes UE 115 and UE 116. In some embodiments, one or more of the eNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G, LTE, LTE-A, WiMAX, WiFi, or other wireless communication technologies.

[0053] Depending on the type of network, the term "base station" or "BS" may refer to any component (or set of components) configured to provide wireless access to a network, such as a transmit point (TP), a transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wirelessly enabled devices. A base station may provide wireless access according to one or more wireless communication protocols, for example, 5G 3GPP New Radio Interface / Access (NR), Long Term Evolution (LTE), Advanced LTE (LTEadvanced, LTE-A), High Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For convenience, the terms "BS" and "TRP" are used interchangeably in this patent document to refer to a network infrastructure component that provides wireless access to a remote terminal. Also, depending on the network type, the term "user equipment" or "UE" may refer to any component, such as a "mobile station," "subscriber station," "remote terminal," "wireless terminal," "reception point," or "user device." For convenience, the terms "user equipment" and "UE" are used in this patent document to refer to a remote wireless device that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile phone or smartphone) or is generally considered a fixed device (such as a desktop computer or a vending machine).

[0054] The dashed lines show the approximate extents of coverage areas 120 and 125, which are shown as approximately circular for purposes of illustration and explanation only. It should be clearly understood that coverage areas associated with eNBs, such as coverage areas 120 and 125, may have other shapes, including irregular shapes, depending on the configuration of the eNB and variations in the radio environment associated with natural and man-made obstacles.

[0055] As described in more detail below, one or more of the UEs 111-116 include circuits, programs, or a combination thereof for efficient transmission structure and format of DL control channels in advanced wireless communication systems. In certain embodiments, one or more of the eNBs 101-103 include circuits, programs, or a combination thereof for efficient transmission structure and format of DL control channels in advanced wireless communication systems.

[0056] although Figure 1 An example of a wireless network is shown, but Figure 1 Various changes may be made. For example, the wireless network may include any number of eNBs and any number of UEs in any suitable arrangement. Furthermore, eNB 101 may communicate directly with any number of UEs and provide these UEs with wireless broadband access to network 130. Similarly, each eNB 102-103 may communicate directly with network 130 and provide UEs with direct wireless broadband access to network 130. In addition, eNB 101, 102, and / or 103 may provide access to other or additional external networks, such as an external telephone network or other types of data networks.

[0057] Figure 2 An example eNB 102 is shown according to an embodiment of the disclosure. Figure 2 The embodiment of the eNB 102 shown is for illustration only, and Figure 1 The eNBs 101 and 103 may have the same or similar configurations. However, eNBs come in a variety of configurations, and Figure 2 The scope of the present disclosure is not limited to any particular implementation of the eNB.

[0058] like Figure 2 As shown, the eNB 102 includes multiple antennas 205a-205n, multiple RF transceivers 210a-210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. The eNB 102 also includes a controller / processor 225, memory 230, and a backhaul or network interface 235.

[0059] RF transceivers 210a-210n receive incoming RF signals from antennas 205a-205n, such as signals transmitted by UEs in network 100. RF transceivers 210a-210n downconvert incoming RF signals to generate IF or baseband signals. The IF or baseband signals are transmitted to RX processing circuitry 220, which generates processed baseband signals by filtering, decoding and / or digitizing the baseband or IF signals. RX processing circuitry 220 transmits the processed baseband signals to controller / processor 225 for further processing.

[0060] The TX processing circuit 215 receives analog or digital data (such as voice data, network data, email, or interactive video game data) from the controller / processor 225. The TX processing circuit 215 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceivers 210a-210n receive the outgoing processed baseband or IF signals from the TX processing circuit 215 and up-convert the baseband or IF signals into RF signals that are transmitted via the antennas 205a-205n.

[0061] The controller / processor 225 may include one or more processors or other processing devices that control the overall operation of the eNB 102. For example, the controller / processor 225 may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 in accordance with well-known principles. The controller / processor 225 may also support additional functionality, such as more advanced wireless communication functionality. For example, the controller / processor 225 may support beamforming or directional routing operations, in which signals outgoing from multiple antennas 205a-205n are weighted differently to effectively direct the outgoing signals in a desired direction. The controller / processor 225 may support any of a variety of other functions in the eNB 102.

[0062] Controller / processor 225 is also capable of running programs and other processes, such as an OS, that reside in memory 230. Controller / processor 225 may move data into or out of memory 230 as required by the running processes.

[0063] The controller / processor 225 is also coupled to a backhaul or network interface 235. The backhaul or network interface 235 allows the eNB 102 to communicate with other devices or systems via a backhaul connection or via a network. The interface 235 may support communication via (multiple) any suitable wired or wireless connection. For example, when the eNB 102 is implemented as part of a cellular communication system (such as a system supporting 5G, LTE, or LTE-A), the interface 235 may allow the eNB 102 to communicate with other eNBs via a wired or wireless backhaul connection. When the eNB 102 is implemented as an access point, the interface 235 may allow the eNB 102 to communicate with a larger network (such as the Internet) via a wired or wireless local area network or via a wired or wireless connection. The interface 235 includes any suitable structure that supports communication via a wired or wireless connection, such as an Ethernet or RF transceiver.

[0064] Memory 230 is coupled to controller / processor 225. A portion of memory 230 may include RAM, and another portion of memory 230 may include flash memory or other ROM.

[0065] although Figure 2 An example of an eNB 102 is shown, but the Figure 2 For example, eNB 102 may include Figure 2 As a specific example, an access point may include any number of interfaces 235, and controller / processor 225 may support routing functions for routing data between different network addresses. As another specific example, although shown as including a single instance of TX processing circuitry 215 and a single instance of RX processing circuitry 220, eNB 102 may include multiple instances of each (such as one for each RF transceiver). And, as specifically desired, Figure 2 Various components in may be combined, further subdivided, or omitted, and additional components may be added.

[0066] Figure 3 An example UE 116 is shown according to an embodiment of the disclosure. Figure 3 The embodiment of UE 116 shown is for illustration only, and Figure 1 UEs 111-115 may have the same or similar configurations. However, UEs appear in a variety of configurations, and Figure 3 The scope of the present disclosure is not limited to any particular implementation of the UE.

[0067] like Figure 3As shown, UE 116 includes antenna 305, radio frequency (RF) transceiver 310, TX processing circuit 315, microphone 320 and receive (RX) processing circuit 325. UE 116 also includes speaker 330, processor 340, input / output (I / O) interface 345, touch screen 350, display 355 and memory 360. Memory 360 includes operating system (OS) 361 and one or more applications 362.

[0068] RF transceiver 310 receives incoming RF signals from antenna 305 transmitted by an eNB of network 100. RF transceiver 310 downconverts the incoming RF signals to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is transmitted to RX processing circuit 325, which generates a processed baseband signal by filtering, decoding and / or digitizing the baseband or IF signal. RX processing circuit 325 transmits the processed baseband signal to speaker 330 (such as for voice data) or to processor 340 for further processing (such as for web browsing data).

[0069] The TX processing circuit 315 receives analog or digital voice data from the microphone 320, or receives other outgoing baseband data (such as network data, email, or interactive video game data) from the processor 340. The TX processing circuit 315 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 310 receives the outgoing processed baseband or IF signal from the TX processing circuit 315, and up-converts the baseband or IF signal into an RF signal transmitted via the antenna 305.

[0070] The processor 340 may include one or more processors or other processing devices and runs an OS 361 stored in the memory 360 to control the overall operation of the UE 116. For example, the processor 340 may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver 310, the RX processing circuit 325, and the TX processing circuit 315 according to well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[0071] The processor 340 is also capable of running other processes and programs resident in the memory 360, such as processes for beam management. The processor 340 can move data into or out of the memory 360 as needed by the running process. In some embodiments, the processor 340 is configured to run applications 362 based on the OS 361 or in response to signals received from the eNB or operator. The processor 340 is also coupled to the I / O interface 345, which provides the UE 116 with the ability to connect to other devices such as laptops and handheld computers. The I / O interface 345 is the communication path between these accessories and the processor 340.

[0072] Processor 340 is also coupled to touch screen 350 and display 355. An operator of UE 116 may input data into UE 116 using touch screen 350. Display 355 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as from a website.

[0073] Memory 360 is coupled to processor 340. A portion of memory 360 may include random access memory (RAM), and another portion of memory 360 may include flash memory or other read-only memory (ROM).

[0074] although Figure 3 An example of UE 116 is shown, but the Figure 3 For example, according to specific needs, Figure 3 The various components in may be combined, further subdivided, or omitted, and additional components may be added. As a specific example, processor 340 may be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Figure 3 The UE 116 is shown configured as a mobile phone or smartphone, but the UE may be configured to operate as other types of mobile or stationary devices.

[0075] The present disclosure relates generally to wireless communication systems, and more particularly to improving PDCCH reception reliability and reducing associated signaling overhead. The communication system includes a downlink (DL) referring to transmissions from a base station or one or more transmission points to a UE, and an uplink (UL) referring to transmissions from a UE to a base station or one or more reception points.

[0076] In order to meet the demand for wireless data traffic that has increased since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also called "super 4G networks" or "post-LTE systems". 5G communication systems are considered to be implemented in higher frequency (millimeter wave) bands, for example, 60GHz bands, in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed in 5G communication systems. In addition, in 5G communication systems, system network improvements are being developed based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, collaborative communications, coordinated multi-points (CoMP), and receiving-end interference elimination. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM) have been developed, and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies have been developed.

[0077] The time unit used for DL ​​signaling or UL signaling on a cell is called a time slot and may include one or more time slot symbols. A time slot symbol may also serve as an additional time unit. A frequency (or bandwidth (BW)) unit is called a resource block (RB). An RB includes multiple sub-carriers (SC). For example, a time slot may have a duration of 0.5 milliseconds or 1 millisecond, including 7 symbols or 14 symbols, respectively, and an RB may have a BW of 180 KHz and include 12 SCs with an inter-SC spacing of 15 KHz or 60 KHz.

[0078] DL signals include data signals that convey information content, control signals that convey DL control information (DCI), and reference signals (RS) also known as pilot signals. The gNB can send data information or DCI through their respective physical DL shared channels (PDSCH) or physical DL control channels (PDCCH). The gNB can send one or more of multiple types of RS, including channel state information RS (CSI-RS) and demodulation RS (DMRS). CSI-RS is intended for UEs to measure channel state information (CSI). DMRS is sent only in the BW of the corresponding PDCCH or PDSCH, and the UE can demodulate data or control information using DMRS.

[0079] Figure 4 An example DL slot structure 400 for PDSCH transmission or PDCCH transmission according to an embodiment of the disclosure is shown. Figure 4 The illustrated embodiment of DL slot structure 400 is for illustration only. Figure 4 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0080] like Figure 4 As shown, time slot 410 includes Symbols 420, in which the gNB sends data information, DCI or DMRS. The DL system BW includes RBs. Each RB includes SC. For example, UE is assigned M PDSCH RBs, for PDSCH transmission BW total SC 430. The PDCCH conveying the DCI is sent through control channel elements (CCE) that are basically distributed over the DL system BW. For example, the first time slot symbol 440 can be used by the gNB to send DCI and DMRS. The second time slot symbol 450 can be used by the gNB to send DCI or data or DMRS. The remaining time slot symbols 460 can be used by the gNB to send PDSCH, DMRS associated with each PDSCH, and CSI-RS. In some time slots, the gNB can also send synchronization signals and system information.

[0081] The UL signal also includes a data signal conveying information content, a control signal conveying UL control information (UCI), and an RS. The UE sends data information or UCI through its respective physical UL shared channel (PUSCH) or physical UL control channel (PUCCH). When the UE sends data information and UCI at the same time, the UE can multiplex both in the PUSCH or send them separately in the corresponding PUSCH and PUCCH. The UCI includes hybrid automatic repeat request acknowledgement (HARQ-ACK) information indicating the UE's correct or incorrect detection of a data transmission block (TB), a scheduling request (SR) indicating whether the UE has data in the UE's buffer, and a CSI report that enables the gNB to select appropriate parameters for PDSCH or PDCCH transmission to the UE.

[0082] The CSI report from the UE may include: a channel quality indicator (CQI), which informs the gNB of the maximum modulation and coding scheme (MCS) for the UE to detect a data TB with a predetermined block error rate (BLER) (such as 10% BLER); a precoding matrix indicator (PMI), which informs the gNB how to precode the signaling to the UE; and a rank indicator (RI), which indicates the transmission rank of the PDSCH. The UL RS includes DMRS and sounding RS (SRS). DMRS is only transmitted in the BW of the respective PUSCH or PUCCH transmission. The gNB can use DMRS to demodulate the information in the respective PUSCH or PUCCH. The UE sends SRS to provide the gNB with UL CSI and, for TDD or flexible duplex systems, also PMI for DL ​​transmissions. UL DMRS or SRS transmissions can be based on the transmission of Zadoff-Chu (ZC) sequences or (in general) CAZAC sequences.

[0083] Figure 5 An example UL slot structure 500 for PUSCH transmission or PUCCH transmission according to an embodiment of the present disclosure is shown. Figure 5 The illustrated embodiment of UL timeslot structure 500 is for illustration only. Figure 5One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0084] like Figure 5 As shown, time slot 510 includes A symbol 520 in which the UE transmits data information, UCI, or an RS including one symbol in which the UE transmits DMRS 530. The UL system BW includes RBs. Each RB includes SCs. The UE is assigned M PUXCH RBs, for PUSCH transmission BW ("X" = S) or for PUCCH transmission BW ("X" = C) SCs 540. The last one or more time slot symbols may be used to multiplex PUCCH transmissions or SRS transmissions from one or more UEs.

[0085] A mixed slot includes symbols for DL ​​transmission, one or more symbols for a guard period (GP), and symbols for UL transmission, similar to a special SF. For example, symbols for DL ​​transmission may convey PDCCH and PDSCH transmissions, while symbols for UL transmission may convey PUCCH transmissions. For example, symbols for DL ​​transmission may convey PDCCH transmissions, while symbols for UL transmission may convey PUSCH and PUCCH transmissions.

[0086] Figure 6 An example hybrid slot structure 600 for DL ​​transmission and UL transmission according to an embodiment of the disclosure is shown. Figure 6 The illustrated embodiment of hybrid time slot structure 600 is for illustration only. Figure 6 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0087] like Figure 6As shown, a slot 610 consists of a number of symbols 620, which include a symbol 630 for DCI transmission and DMRS in the corresponding PDCCH, four symbols 640 for data transmission in the corresponding PDSCH, a GP symbol 650 that provides a guard time for the UE to switch from DL reception to UL transmission, and a UL symbol 660 for sending UCI on the PUCCH. In general, any division between DL symbols and UL symbols of a mixed slot is possible by sliding the position of the GP symbol from the second symbol of the slot to the second to last symbol of the slot. The GP can also be shorter than one slot symbol, and in the case of a shorter symbol duration, the additional duration can be used for DL ​​transmission or for UL transmission. The GP symbols do not need to be explicitly included in the slot structure and can actually be provided from the gNB scheduler by not scheduling transmissions to or from the UE in these symbols.

[0088] DL and UL transmissions may be based on an Orthogonal Frequency Division Multiplexing (OFDM) waveform including a variation using DFT precoding, referred to as DFT-spread OFDM.

[0089] Figure 7 An example transmitter structure 700 using OFDM according to an embodiment of the disclosure is shown. Figure 7 The illustrated embodiment of transmitter structure 700 is for illustration only. Figure 7 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0090] like Figure 7 As shown, information bits 710 such as DCI bits or data bits are encoded by an encoder 720, rate matched to assigned time / frequency resources by a rate matcher 730, and modulated by a modulator 740. Subsequently, the modulated coded symbols and DMRS or CSI-RS 750 are mapped to SC 760 by an SC mapping unit 765, an inverse fast Fourier transform (IFFT) is performed by a filter 770, a cyclic prefix (CP) is added by a CP insertion unit 780, and the resulting signal is filtered by a filter 790 and transmitted by a radio frequency (RF) unit 795.

[0091] Figure 8 An example receiver structure 800 using OFDM is shown according to an embodiment of the disclosure. Figure 8 The illustrated embodiment of receiver structure 800 is for illustration only. Figure 8One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0092] like Figure 8 As shown, the received signal 810 is filtered by a filter 820, a CP removal unit removes the CP 830, a filter 840 applies a fast Fourier transform (FFT), an SC demapping unit 850 demaps the SC selected by a BW selector unit 855, received symbols are demodulated by a channel estimator and demodulator unit 860, a rate dematcher 870 restores rate matching, and a decoder 880 decodes the resulting bits to provide information bits 890.

[0093] The UE typically monitors multiple candidate locations for corresponding potential PDCCH transmissions to decode multiple DCI formats in a time slot. The DCI format includes cyclic redundancy check (CRC) bits so that the UE can confirm the correct detection of the DCI format. The DCI format type is identified by a radio network temporary identifier (RNTI) that scrambles the CRC bits. For DCI formats that schedule PDSCH or PUSCH to a single UE, the RNTI can be a cell RNTI (C-RNTI) and acts as a UE identifier.

[0094] For DCI formats that schedule PDSCH that conveys system information (SI), the RNTI may be an SI-RNTI. For DCI formats that schedule PDSCH that provides random access responses (RARs), the RNTI may be an RA-RNTI. For DCI formats that provide TPC commands to a group of UEs, the RNTI may be a TPC-PUSCH-RNTI or a TPC-PUCCH-RNTI. Each RNTI type may be configured to the UE via higher layer signaling, such as RRC signaling. The DCI format that schedules PDSCH transmissions to the UE is also referred to as a DL DCI format or DL ​​assignment, while the DCI format that schedules PUSCH transmissions from the UE is also referred to as a UL DCI format or UL grant.

[0095] Fig. 9 An example encoding process 900 of a DCI format according to an embodiment of the present disclosure is shown. Fig. 9 The illustrated embodiment of encoding process 900 is for illustration only. Fig. 9 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0096] like Fig. 9 As shown, the gNB encodes and transmits each DCI format separately in the corresponding PDCCH. When applicable, the RNTI of the UE for which the DCI format is intended masks the CRC of the DCI format codeword to enable the UE to identify the DCI format. For example, the CRC and RNTI may include 16 bits. Alternatively, when the RNTI is not included in the DCI format, a DCI format type indicator field may be included in the DCI format. A CRC calculation unit 920 is used to determine the CRC of the (uncoded) DCI format bits 910, and an exclusive OR (XOR) operation unit 930 between the CRC bits and the RNTI bits 940 is used to mask the CRC. The XOR operation is defined as XOR(0,0)=0, XOR(0,1)=1, XOR(1,0)=1, XOR(1,1)=0. A CRC append unit 950 is used to append the masked CRC bits to the DCI format information bits. The encoder 960 performs channel coding, such as tail-biting convolutional coding or polar coding, followed by rate matching to the allocated resources by the rate matcher 970. The interleaving and modulation unit 980 applies interleaving and modulation, such as QPSK, and the output control signal 990 is transmitted.

[0097] Fig.10 An example decoding process 1000 of a DCI format for use by a UE according to an embodiment of the present disclosure is shown. Fig.10 The illustrated embodiment of decoding process 1000 is for illustration only. Fig.10 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0098] like Fig.10 As shown, the received control signal 1010 is demodulated and deinterleaved by a demodulator and deinterleaver 1020. A rate matcher 1030 recovers the rate matching applied at the gNB transmitter, and a decoder 1040 decodes the resulting bits. After decoding, a CRC extractor 1050 extracts the CRC bits and provides DCI format information bits 1060. The DCI format information bits are demasked 1070 by an XOR operation with the RNTI 1080 (when applicable), and a CRC check is performed by unit 1090. When the CRC check succeeds (checksum is zero), the DCI format information bits are considered valid. When the CRC check is unsuccessful, the DCI format information bits are considered invalid.

[0099] PDCCH transmissions are in RBs and symbols of control resource sets. A UE may be configured with RBs and symbols of one or more control resource sets. PDCCH is transmitted using an aggregation of one or several control channel elements (CCEs). Blocks of coded and modulated symbols of the DCI format are sequentially mapped to resource elements (k, l) across SC index k and slot symbol l on the associated antenna port as part of the CCE assigned to the PDCCH transmission. PDCCH transmissions may be distributed in frequency, then also referred to as interleaved PDCCH transmissions, or concentrated in frequency, then also referred to as non-interleaved PDCCH transmissions.

[0100] For example, l∈{0,1}. The PDCCH search space can be common to UEs, or when the UE is configured with n RNTI The C-RNTI can be UE-specific. For example, for the common search space Y k is set to 0 for both CCE aggregation levels L=4 and L=8, while for the UE-specific search space at CCE aggregation level L Variable Y k By Y k =(A·Y k-1 )mod D definition, where Y -1 =n RNTI ≠0, A=39827, D=65537, and k is the time slot number. For example, for an aggregation level of L CCEs, the CCE of PDCCH candidate m is in the N CCE,k The position of a CCE in subframe k can be determined as When a UE is not configured with a C-RNTI, the search space is common to all UEs.

[0101] An important goal of the design of PDCCH transmissions is to improve their respective reliability. This can be achieved through several mechanisms, including supporting frequency diversity or beamforming, enabling accurate channel estimation, improved coverage, and minimization of the size of the DCI format. Improving the reliability of PDCCH transmissions can provide increased throughput because the decoding of the PDCCH of the DCI format that conveys the scheduling of data transmission to or from one or more UEs is less likely to be incorrect, and provides reduced overhead for PDCCH transmissions because fewer resources need to be used, allowing more resources to be used for data transmission. In addition, the DCI format can enable dynamic switching of transmission modes while minimizing the associated payload.

[0102] PDCCH transmissions also need to be able to schedule PDSCH transmissions with reduced latency and improved reception reliability. This typically means that PDCCH and PDSCH transmissions are on a small number of symbols, PDSCH transmissions convey small transport block sizes, and PDCCH can represent significant (material) overhead. In this case, it is important to minimize the overhead associated with PDCCH transmissions by enabling reuse of PDSCH demodulation for DMRS used for PDCCH demodulation.

[0103] UEs communicating with a gNB need to be able to perform time tracking and frequency tracking in order to be able to maintain reliable communication with the gNB. Typically, this is achieved by the gNB sending RS that the UE can use for time tracking and frequency tracking. In order to minimize the overhead associated with the transmission of such RS, it is desirable that the RS is not sent continuously, or even periodically, and that the RS can be an RS that is also used for other functions, such as DMRS for PDCCH demodulation.

[0104] Therefore, there is a need to design a PDCCH transmission with frequency diversity enabled with enhanced channel estimation. There is a need to design a PDCCH transmission with beamforming and enhanced channel estimation enabled. There is a need to enable DMRS reuse for demodulation of PDCCH transmissions and PDSCH transmissions. There is also a need to enable configurable CCE aggregation levels for PDCCH transmissions in the common search space. Finally, there is another need to enable DMRS reuse for time tracking and frequency tracking and for demodulation of PDCCH transmissions.

[0105] In some embodiments, a CCE structure for distributed PDCCH transmissions that depends on the corresponding aggregation level is considered to enable frequency diversity and enhanced channel estimation. The use of small CCE aggregation levels is generally associated with UEs that experience relatively high SINRs, while the use of large CCE aggregation levels is generally associated with UEs that experience relatively low SINRs. Channel estimation accuracy is strongly dependent on SINR. The lower the SINR, the worse the channel estimation accuracy, and the greater the decrease in PDCCH reception reliability due to inaccurate channel estimation. In contrast, frequency diversity is a property of the PDCCH transmission structure and does not depend on SINR. Therefore, the design goal is to enable sufficient frequency diversity while also enabling the accuracy of channel estimation to increase with the increase of the CCE aggregation level of the associated PDCCH transmission. Typically, frequency diversity of about two or four orders of magnitude is sufficient to capture almost all of the frequency diversity gain provided by the channel medium.

[0106] The following description assumes that one CCE includes four RBs, but any other number of RBs (such as six RBs) may also be applicable. For frequency-distributed PDCCH transmissions including one CCE or four RBs, the RBs may be distributed in frequency and not adjacent in frequency. This enables PDCCH transmissions to capture almost all of the frequency diversity gain that the channel medium can provide, but the DMRS used for channel estimation needs to be confined within each RB, and it is generally not advantageous for the UE to filter the channel estimates obtained on the frequency-distributed RBs. An RB is equivalent to a resource element group (REG).

[0107] For frequency-distributed PDCCH transmissions including two CCEs or eight RBs, channel estimation can be improved by distributing four pairs of RBs in frequency. Then, to demodulate the PDCCH candidate including two CCEs, the UE can filter the DMRS in the RB pair, assuming the same DMRS precoding is adopted in each pair of RBs to improve the corresponding reliability of the channel estimation. Similarly, for frequency-distributed PDCCH transmissions including four or eight CCEs (corresponding to 16 or 32 RBs, respectively), the transmission can be in blocks of four RBs or blocks of eight RBs distributed in frequency (assuming that the transmission bandwidth is greater than 32 RBs, at four corresponding frequency positions).

[0108] The UE can then filter the DMRS within the corresponding RB block and improve the corresponding reliability of the channel estimate, while the associated PDCCH transmission can obtain all frequency diversity gains from the channel medium. It is also possible for frequency distributed PDCCH transmission to start with an aggregation level of one CCE in units of RB blocks. For example, when the CCE includes six RBs, a PDCCH transmission to the UE with an aggregation level of one CCE can be in units of blocks of two RBs over three frequency non-contiguous blocks of two RBs in the DL system bandwidth configured for PDCCH transmission to the UE.

[0109] Generally speaking, for CCE, the number of blocks of frequency-contiguous RBs that a UE can configure by a higher layer is N. bundle RBs, and for N bundle Total RBs frequency distribution blocks, the distributed CCE to RB mapping can be N bundle For example, for a control resource set including one symbol, and N bundle =2, exists frequency distribution blocks, and for and N bundle =6, Only N existsbundle = a block of 6 frequency-contiguous RBs. For a given DMRS antenna port is an RB, the UE can assume that the same precoder applies to all RBs in the RB bundle. The RB bundle may also be larger than

[0110] This may be useful for transmission of UE-common PDCCH, for example, in a common search space (CSS), where the DMRS may be UE-common. total The UE can be configured to transmit PDCCH in a control resource set with a BW of RBs, and the number can be equal to N total 、N total / 2 or N total The same DMRS precoding is used on RBs of / 4. This can allow the UE to filter the DMRS over a larger number of RBs and improve channel estimation.

[0111] For CSS, N bundle It may be predefined in system operation or signaled through broadcast system information such as a master information block (MIB) or a secondary system information block (SIB). For example, a PDCCH scheduling transmission of a first SIB may have a bundle size predetermined in system operation, while a PDCCH scheduling transmission of a second SIB or RAR may have a bundle size signaled in the first SIB.

[0112] A CCE can be transmitted in one OFDM symbol. If necessary, coverage enhancement can be obtained by using a larger CCE aggregation level for PDCCH transmission and using the corresponding CCEs distributed over multiple OFDM symbols. For example, for a PDCCH including OFDM symbols, and a PDCCH candidate corresponding to the aggregation level of L CCEs. In the case of frequency-first REG to CCE mapping, CCE i, i = 0, ..., L-1 can be located in a region with In the OFDM symbol of the determined index.

[0113] For including DL control resource set of RBs, the first RB block can be selected from the Starting from the RB of Starting from RB, the third RB block can be started from the one with index RB, and the fourth RB block can start from the one with index where O is a UE-specific offset or a cell-specific offset, which may be determined, for example, from the C-RNTI about the UE, or explicitly configured by the gNB using higher layer signaling, or determined by the identity of the cell sending the PDCCH.

[0114] Fig.11 An example distributed PDCCH transmission structure 1100 depending on corresponding CCE aggregation levels according to an embodiment of the present disclosure is shown. Fig.11 The illustrated embodiment of the distributed PDCCH transmission structure 1100 is for illustration only. Fig.11 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0115] For PDCCH transmission with an aggregation level of one CCE including four RBs, the RBs are distributed per single RB in frequency 1110. For PDCCH transmission with an aggregation level of two CCEs and with time-first mapping of the CCEs, the corresponding eight RBs are distributed in frequency in blocks of two adjacent RBs, where the first RB from the RB block is on the first OFDM symbol of the first CCE, and the second RB from the RB block is on the second OFDM symbol of the second CCE 1120.

[0116] For PDCCH transmissions with an aggregation level of two CCEs and frequency-first mapping of CCEs, the corresponding eight RBs are distributed in blocks of two adjacent RBs in frequency, where each RB block is on the same OFDM symbol 1130. A similar structure may apply to PDCCH transmissions with CCE aggregation levels greater than two CCEs. For time-first mapping, when there are fewer OFDM symbols than CCEs in the CCE aggregation level, for example, when there are two OFDM symbols for mapping an aggregation level of four CCEs, wrap around may be applied to the mapping of CCEs 1140.

[0117] Fig.11 The mapping of CCE to RB in takes into account the interleaving of RBs of each OFDM symbol to obtain the distributed (non-contiguous) RB index in the physical domain from the continuous (contiguous) RB index in the logical domain forming the CCE. Otherwise, if the interleaving is not performed on each OFDM symbol but on two OFDM symbols, it is impossible for the RB of a given CCE to be located in only one OFDM symbol.

[0118] Different CCE to OFDM symbol mappings may be configured for different PDCCH transmission types. For example, time-first mapping may be applied to beamformed, localized PDCCH transmissions to a UE in order to maximize the centralization of the beamformed PDCCH transmissions and maximize the associated precoding gain, while frequency-first mapping may be applied to frequency-distributed PDCCH transmissions using transmitter antenna diversity in order to maximize frequency diversity gain.

[0119] For PDCCH transmission with aggregation level of one CCE (including four RBs) and time-first CCE-to-REG mapping, the RBs of the REG bundle are first distributed in time per OFDM symbol. (The number of RBs at an aggregation level less than L CCEs ) OFDM symbols, the foldback is applied in the time domain to N bundle RBs, and the The first RB is continuous with the first RB in the first OFDM symbol. The first RB is continuous with the first RB in the second OFDM symbol. The first RB is continuous with the second RB in the first OFDM symbol. Continuous with the first RB in the second OFDM symbol, and so on. RBs are continuous with p-1 RBs in q OFDM symbols.

[0120] Fig.12 An example localized PDCCH transmission structure 1200 depending on corresponding CCE aggregation levels according to an embodiment of the present disclosure is shown. Fig.12 The illustrated embodiment of the localized PDCCH transmission structure 1200 is for illustration only. Fig.12 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0121] like Fig.12 As shown, the DL control resource set includes Symbols 1210 and aggregation level of one CCE (including four RBs) for PDCCH transmission, for each PDCCH candidate, the first RB and the third RB are frequency-continuously mapped to the first OFDM symbol, and the second RB and the fourth RB are frequency-continuously mapped to the second OFDM symbol. For the DL control resource set including Symbols 1220 and an aggregation level of one CCE (including four RBs) are transmitted, the first RB, the second RB, the third RB and the fourth RB are mapped to the same RB index on the first OFDM symbol, the second OFDM symbol, the third OFDM symbol and the fourth OFDM symbol, respectively, and the PDCCH candidates are distributed in frequency.

[0122] like Fig.11 or Fig.12 The CCE mapping shown may allow UEs with different bandwidth reception capabilities to coexist in the same bandwidth, and allow common search spaces and UE-specific search spaces to coexist in the same DL control resource set.

[0123] The UE may be configured to monitor different DL control resource sets associated with different search spaces in different symbols of a time slot or in different time slots. The configuration may be performed by UE group common higher layer signaling or by UE specific higher layer signaling. For example, the UE may be configured to monitor a first DL control resource set associated with a common search space in the first one or more symbols of a time slot, and may be configured to monitor a second DL control resource set associated with a UE specific search space in the second one or more symbols of the time slot (e.g., immediately after the first one or more symbols of the time slot).

[0124] For example, the UE may be configured to monitor a first set of DL control resources associated with a first common search space in a first one or more symbols of a time slot, and separately configured to monitor a second set of DL control resources associated with a second common search space in a second one or more symbols of the time slot (e.g., immediately after the first one or more symbols of the time slot). For example, the UE may be configured to monitor a first set of DL control resources associated with a first UE-specific search space, e.g., for transmissions from a first beam, in a first one or more symbols of a time slot, and configured to monitor a second set of DL control resources associated with a second UE-specific search space, e.g., for transmissions from a second beam, in a second one or more symbols of a time slot (e.g., immediately after the first one or more symbols of the time slot).

[0125] For example, the UE may be configured to monitor a first set of DL control resources in a first number of slots in a slot cycle according to parameters associated with a common search space, such as PDCCH candidates or a transmission scheme (such as distributed or centralized PDCCH transmission), and monitor a first set of DL control resources in a second number of slots in a slot cycle according to parameters associated with a UE-specific search space. The slot cycle may be determined in system operation, such as 10 slots or 20 slots, or configured to the UE by UE group common or UE-specific higher layer signaling. The UE's monitoring of the search space refers to the UE performing a decoding operation on the PDCCH candidate using the corresponding CCE in the search space.

[0126] The UE may monitor UE-specific DCI formats in both a common search space and a UE-specific search space. To enable this functionality, the UE may adjust parameters for controlling the reception of UE-specific DCI formats in a resource set based on the associated search space type (common or UE-specific). For example, the sequence for scrambling the transmission of a DMRS associated with a UE-specific DCI format transmission in a PDCCH may be a first scrambling sequence when the transmission is in a common search space and a second scrambling sequence when the transmission is in a UE-specific search space. For example, the number of subcarriers used for DMRS transmission in an RB may have a first value in a common search space and a second value in a UE-specific search space. For example, a first transmission scheme, such as transmit antenna diversity for distributed PDCCH transmission, may be associated with DCI format reception in a common search space, while a second transmission scheme, such as precoding / beamforming for centralized PDCCH transmission, may be associated with DCI format reception in a UE-specific search space.

[0127] The UE may also be configured to monitor a first search space having a first periodicity and a second search space having a second periodicity. For example, the first search space may be a common search space and the periodicity may be five time slots, while the second search space may be a UE-specific search space and the periodicity may be one time slot. For example, the first search space may be a first UE-specific search space and the periodicity may be one time slot, while the second search space may be a second UE-specific search space and the periodicity may be one-fifth or one-half time slot. Thus, the number of decoding operations that the UE may perform during a time period may depend on the number of search spaces that the UE monitors during the time period.

[0128] For example, during a time period when the UE does not monitor a common search space, an associated PDCCH decoding operation may be used to monitor a UE-specific search space. At least for some CCE aggregation levels of the UE-specific search space, during a time period when the UE does not monitor a common search space, the number of PDCCH candidates may be larger. For example, during a time period when the UE does not monitor a UE-specific search space associated with a longer periodicity, a corresponding PDCCH decoding operation may be allocated to monitor a UE-specific search space associated with a shorter periodicity. During a time period when the UE does not monitor a UE-specific search space with a longer monitoring periodicity, at least for some CCE aggregation levels of the UE-specific search space with a shorter monitoring periodicity, the number of PDCCH candidates may be larger.

[0129] For each serving cell, higher layer signaling configures P control resource sets for the UE. For a control resource set p, 0≤p<P, the configuration may include: subcarrier spacing and CP length; first symbol index provided by the higher layer parameter CORESET-start-symb; number of consecutive symbols provided by the higher layer parameter [CORESET-time-duration]; set of resource blocks provided by the higher layer parameter CORESET-freq-dom; CCE to REG mapping provided by the higher layer parameter CORESET-trans-type; and / or REG bundle size in case of interleaved CCE to REG mapping provided by the higher layer parameter CORESET-REG-bundle-size; whether PDCCH transmission is distributed or centralized provided by the higher layer parameter CORESET-CCE-REG-mapping-type, or quasi-collocation of antenna ports provided by the higher layer parameter [CORESET-QCL-ConfigId].

[0130] For each serving cell and for each DCI format that the UE is configured to monitor PDCCH, the UE is configured with the following associations with control resource sets: the set of control resource sets via the higher layer parameter DCI-to-CORESET-map; the number of PDCCH candidates per CCE aggregation level L per control resource set in the set of control resource sets via the higher layer parameter CORESET-candidates-DCI; and / or in non-DRX mode operation, the number of PDCCH candidates per control resource set in the set of control resource sets via the higher layer parameter CORESET-monitor-period-DCI. p The monitoring periodicity of each symbol.

[0131] Each control resource set consists of resources numbered from 0 to The set of CCEs, where is the monitoring period k p The monitoring period may be indexed (modulo) within a predetermined time period, such as a number of system frame numbers, a system frame number cycle, or a predetermined duration (such as 40 milliseconds).

[0132] The set of PDCCH candidates monitored by the UE is defined according to the PDCCH UE-specific search space. PDCCH UE-specific search space at CCE aggregation level L (such as L∈{1,2,4,8,16}) Defined by the set of PDCCH candidates regarding CCE aggregation level L.

[0133] If the UE is configured with the higher layer parameter cif-InSchedulingCell, the carrier indicator field value corresponds to cif-InSchedulingCell.

[0134] For a serving cell where the UE monitors PDCCH candidates in a UE-specific search space, if the UE is not configured with a carrier indicator field, the UE monitors PDCCH candidates without a carrier indicator field. For a serving cell where the UE monitors PDCCH candidates in a UE-specific search space, if the UE is configured with a carrier indicator field, the UE monitors PDCCH candidates with a carrier indicator field.

[0135] For control resource set p and for DCI format A, for example, for P=2 control resource sets, the value corresponding to the carrier indicator field value n CI PDCCH candidates in the search space of the serving cell The corresponding CCE is given by:

[0136]

[0137] in, Y p，-1 =n RNTI ≠0, A 0 =39827, A 1 =39829, and D=65537; i=0,...,L-1; if the UE is configured with a carrier indication field for the serving cell on which to monitor the PDCCH, then n CI is the carrier indication field value; otherwise, n CI =0; is the number of all configurations of CCE aggregation level L in control resource set p CI The maximum number of PDCCH candidates in the value, which may be among all configured DCI formats or only for DCI format A; in is with n CI The corresponding number of PDCCH candidates that the UE is configured to monitor for the serving cell for aggregation level L; n RNTI is the RNTI value used for the corresponding DCI format.

[0138] because The PDCCH monitoring period k can be different p Different, so The value of may depend on the PDCCH monitoring period, and therefore, Can be Instead. Therefore, It can be the number of all configurations of CCE aggregation level L in control resource set p. CI value and is in PDCCH monitoring period k p The maximum number of PDCCH candidates for all configured DCI formats or only for DCI format A. Otherwise, It can be the number of all configurations of CCE aggregation level L in control resource set p. CI The maximum number of PDCCH candidates among all configured DCI formats over the value and over all overlapping PDCCH monitoring periods.

[0139] A UE configured to monitor PDCCH candidates of a given DCI format size with a carrier indicator field and a CRC scrambled by a C-RNTI in a given serving cell (where the PDCCH candidate may have one or more possible values ​​of the carrier indicator field of the given DCI format size) may assume that the PDCCH candidate with the given DCI format size may be sent in the given serving cell in any PDCCH UE-specific search space corresponding to any possible value of the carrier indicator field of the given DCI format size.

[0140] It is generally not possible to use the same DMRS for PDCCH and PDSCH demodulation because the PDCCH transmission scheme may be different from the PDSCH transmission scheme, and the PDCCH transmission bandwidth may be different from the PDSCH transmission bandwidth. For example, a PDCCH transmission to a UE may not have spatial multiplexing of layers and be in a first bandwidth, while a PDSCH transmission to a UE may have spatial multiplexing of layers and be in a second bandwidth.

[0141] To reduce the overhead associated with the first DMRS transmission for PDCCH demodulation and the second DMRS transmission for PDSCH demodulation, especially for transmissions of small data transport block sizes that typically do not benefit from spatial multiplexing of layers, the UE may assume the same transmission scheme for PDCCH transmission and PDSCH transmission. In addition, the PDCCH transmission bandwidth may be included in the PDSCH transmission bandwidth.

[0142] Fig.13 An example PDCCH transmission and PDSCH transmission 1300 using the same DMRS for demodulation is shown according to an embodiment of the disclosure. Fig.13 The illustrated embodiment of a PDCCH transmission and a PDSCH transmission 1300 is for illustration only. Fig.13 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0143] like Fig.13 As shown, PDCCH transmission is on the first OFDM symbol, while PDSCH transmission is on the first OFDM symbol and the second OFDM symbol 1310. PDCCH transmission is on many RBs, which are subsets of many RBs used for PDSCH transmission. For example, the RB used for PDCCH transmission can be the center C RBs of D≥C RBs used for PDSCH transmission. In addition to the subcarriers used to send control information and data information, respectively, the PDCCH RB 1320 and PDSCH RB in the first OFDM symbol also include subcarriers for DMRS transmission. For example, one subcarrier in every three subcarriers can be used for DMRS transmission. The PDSCH RB 1340 in the second OFDM symbol does not include any subcarriers for DMRS transmission. For demodulation of PDCCH transmission or PDSCH transmission, the UE can filter the DMRS subcarriers in both the RB used for PDSCH transmission and the RB used for PDCCH transmission in the first symbol.

[0144] This also reduces the computational complexity and power consumption of the UE, since the UE only needs to obtain one channel estimate to demodulate the PDCCH transmission and the PDSCH transmission. In order for the DMRS filtering on the RBs in the first OFDM symbol to produce a valid channel estimate, the DMRS needs to use the same precoding on all RBs in the first OFDM symbol, and the same precoding is also required for PDCCH transmission and PDSCH transmission. For example, both the PDCCH transmission and the PDSCH transmission can be based on the same transmitter diversity scheme. For example, both the PDCCH transmission and the PDSCH transmission can be based on the same precoding used for beamforming transmission.

[0145] Since DMRS can be power boosted to improve channel estimation, it may be beneficial to avoid placing DMRS transmissions in adjacent cells on the same subcarriers in the same slot symbols, otherwise the usefulness gained from the increased DMRS transmission power may be largely negated due to mutual interference between the power boosted DMRS. Therefore, the location (subcarrier) used for DMRS transmission in an RB may be pseudo-random or indicated by the gNB (e.g., by association with a synchronization signal sequence used by the gNB). The pseudo-random determination may be based on the identity of the cell transmitting the DMRS.

[0146] For example, for DMRS transmission on 4 equally spaced subcarriers in a RB of 12 subcarriers from an antenna port, the subcarrier with DMRS transmission in the RB may be determined as k DMRS =3k+δ shift mod3, where k = 0, 1, 2, 3, and in is the cell ID obtained by the UE from the initial synchronization process with the cell. For example, for DMRS transmission on 2 equidistant subcarriers in an RB of 12 subcarriers from an antenna port, the subcarrier with DMRS transmission in the RB can be determined as k DMRS =6k+δ shift mod 6, where k = 0, 1, and The indication by the gNB may be based on a sequence used to send a synchronization signal, such as a primary synchronization signal or a secondary synchronization signal.

[0147] When distributed PDCCH transmission and localized PDCCH transmission can be multiplexed in the same DL control resource set, the distributed PDCCH transmission can be based on a transmit diversity scheme using precoder cycling, where, in some RBs, the precoder can also be associated with the localized PDCCH transmission. In this case, the UE cannot assume that the DMRS in the PRB uses the same precoder in different time slots or frequency-contiguous RBs, and cannot utilize the DMRS for time tracking or frequency tracking.

[0148] In order to bypass the above-mentioned limitation on the UE using DMRS associated with demodulation of PDCCH transmission for time tracking and frequency tracking, the UE can be informed in advance that the DMRS uses the same precoding in the predetermined time slots or predetermined RBs (with DMRS transmission). The predetermined time slots or predetermined RBs can be defined in the system operation, such as one time slot every 5 milliseconds, or all RBs of the DL control resource set, or can be signaled by system information. For example, the predetermined time slot or predetermined RB can be determined as the time slot or RB in which the gNB sends the PDCCH scheduling the first system information block. Based on the assumption that the DMRS transmission in the predetermined RBs of the DL control resource set and in the predetermined time slot uses the same precoding, the UE can use the DMRS to perform time tracking or frequency tracking in addition to channel estimation.

[0149] For the PDCCH transmit diversity scheme using precoder cycling, it is possible to bundle For example, for N consecutive RBs, total =4·N bundle and two transmitter antennas, the first N bundle The precoder in the first N RBs can be {1; 1}, the second N bundle The precoder in the Nth RB can be {1; -1}, and the third N bundle The precoder in the first RB can be {1; j}, and the fourth N bundle The precoders in each RB can be {1; -j}. By knowing the precoder applied to each RB, the UE can remove the precoder and obtain N total Unprecoded DMRS is received on RBs. Unprecoded DMRS can be used for other purposes, such as wideband channel estimation or time tracking when received at different time instances.

[0150] Fig.14 Example operations 1400 are shown for a UE to assume the same DMRS precoding in a predetermined time slot and a predetermined RB of a DL control resource set according to an embodiment of the present disclosure. Fig.14 The illustrated embodiment of operation 1400 is for illustration only. Fig.14 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0151] like Fig.14As shown, the gNB transmits DMRS in the DL control resource set 1410. The UE receives the DMRS 1420 and determines whether it can assume fixed DMRS precoding in the slot 1430. This determination can be based on a predetermined slot periodicity, or in a slot pattern signaled by system information from the gNB, for example, using a bitmap that repeats periodically in time. The RBs may include all RBs in the DL control resource set with DMRS transmission, or may be signaled by the gNB using higher layer signaling.

[0152] For example, when the RBs associated with the common search space are not all RBs in the DL control resource set, the RBs may be those RBs in the common search space used for PDCCH transmission. And, when the UE is configured with multiple DL control resource sets, the RBs may be those RBs in the first DL control resource set that may also include those RBs that send UE group common DL control signaling in the time slot. When the UE cannot assume fixed DMRS precoding in the time slot, the UE may not use the DMRS received in the time slot for time tracking or frequency tracking 1440. When the UE can assume fixed DMRS precoding in the time slot, the UE may use the DMRS received in the time slot for time tracking or frequency tracking 1450.

[0153] For PDSCH transmission or for PUSCH transmission, there may be several transmission schemes. When the transmission scheme is configured by higher layer signaling, the UE may monitor a DCI format including only necessary fields for the transmission scheme, and different DCI formats may be associated with different transmission schemes.

[0154] While providing operational simplicity, semi-static configuration of the transmission scheme for PDSCH or PUSCH is disadvantageous because it does not enable the gNB to quickly adapt the transmission scheme for the UE, for example, based on changes in the channel medium experienced by the UE, but instead requires reliance on reconfiguration by higher layer signaling. When the dynamic change between multiple sets of transmission schemes is based on the use of corresponding multiple sets of DCI formats having respective multiple sizes, the UE needs to decode each of the multiple DCI formats in each slot to determine the transmission scheme for the corresponding PDSCH transmission or PUSCH transmission, and this increases the number of decoding operations that the UE needs to perform in each slot, for example, by a factor equal to the number of multiple DCI formats having different sizes. Instead, a single DCI format including a flag indicating the corresponding transmission scheme may be used so that the UE decodes a single DCI format in each slot.

[0155] The tradeoff for reducing the number of decoding operations is occasional unnecessary overhead when scheduling a PDSCH transmission or a PUSCH transmission with a transmission scheme that does not require all fields of a DCI format or requires fields with a reduced number of bits. A transmission scheme that may be associated with a single DCI format may be a transmission scheme that requires a similar number of bits, such as a transmission scheme that is at most 20% more than the transmission scheme that requires the largest number of bits and that determines the size of the DCI format.

[0156] In order to reduce the overhead associated with introducing a flag in the DCI format (which can indicate multiple transmission schemes, such as more than two transmission schemes), the flag can have a nested structure and include only one additional bit relative to the number of bits required to schedule PDSCH transmission or PUSCH transmission using the transmission scheme that requires the maximum number of bits in the DCI format (referred to as the first transmission scheme).

[0157] The flag is located at the beginning of the DCI format. The UE may first check the value of the binary flag. When the flag value is a first value, the UE may determine that the transmission scheme for the associated PDSCH or PUSCH transmission is the first transmission scheme. When the flag value is a second value, the UE may determine the number of additional bits in the DCI format that are not used for scheduling associated with the first transmission scheme and that may act as an extended flag. For example, the position of the additional bits when the flag value is a second value may be after the flag or may be at the end of the DCI format (the last bit of the DCI format) relative to the first transmission scheme. For example, when the second transmission scheme having the second largest number of required bits in the DCI format requires two fewer bits, the values ​​of the two bits may be used to indicate whether the DCI format schedules the corresponding PDSCH or PUSCH transmission with the second, third, fourth, or fifth (if any) transmission scheme.

[0158] Fig.15 An example operation of a DCI format according to an embodiment of the present disclosure is shown, the DCI format including a binary flag to indicate a transmission scheme for PDSCH transmission or PUSCH transmission among multiple transmission schemes. Fig.15 The illustrated embodiment of operation 1500 is for illustration only. Fig.15 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0159] like Fig.15As shown, the gNB transmits a DCI format including a "flag" field to the UE via the PDCCH 1510. The UE detects the DCI format 1520 and determines whether the value of the "flag" field is equal to "1" 1530. When not equal, the UE receives an associated PDSCH transmission or PUSCH transmission with the first corresponding transmission scheme 1540. When equal, the UE determines whether the value of an additional bit is equal to "1" 1550, which is included in the DCI format for scheduling with the first transmission scheme but not for scheduling with any other transmission scheme. When not equal, the UE receives an associated PDSCH transmission or PUSCH transmission with the second corresponding transmission scheme 1560; otherwise, the UE receives an associated PDSCH transmission or PUSCH transmission with the third corresponding transmission scheme 1570.

[0160] A predetermined DCI format transmitted in a UE-specific search space, such as a first DCI format (fallback DCI format) monitored by the UE, which has a smaller size than a second DCI format (non-fallback DCI format) monitored by the UE, may be used to provide fallback operation during a period of time when the parameters of transmissions to or from the UE are reconfigured by the gNB. For example, a DCI format scheduling a PDSCH transmission to the UE may include a field indicating a slot offset (including a symbol within a slot), or a field indicating resources for a PUCCH transmission by the UE in response to reception of data conveyed by the PDCCH.

[0161] The UE may be configured by a higher layer with a set of time slot offsets or a set of PUCCH resources, and the corresponding field may indicate a value from the corresponding set. During a time period associated with reconfiguration of values ​​in one or more sets of these values, or before values ​​in the set of these values ​​are configured by UE-specific higher layer signaling, the UE may use the value indicated by the UE group common system information. The UE may determine whether to use the value signaled by UE group common high-layer signaling (system information) or the value signaled by UE-specific higher layer signaling based on the associated DCI format, and the UE may use the former value when the UE detects a first DCI format (such as a fallback DCI format), and use the latter value when the UE detects a second DCI format (such as a non-fallback DCI format).

[0162] The DCI formats can also be the same and distinguished by a flag value, such as Fig.15As shown. For example, the flag value may correspond to the use of parameter values, such as HARQ-ACK transmission timing offset or PUCCH resources for HARQ-ACK transmission, or a slot timing offset for PDSCH or PUSCH transmission relative to the time slot of the transmission of the associated DCI format, which parameter values ​​are signaled to the UE via UE-common higher layer signaling. Therefore, the flag field in the DCI format, in addition to providing a distinction in the transmission scheme for the associated PDSCH transmission or PUSCH transmission, may also provide a distinction in the interpretation of the values ​​of other fields in the DCI format according to the values ​​configured by UE-common higher layer signaling or UE-specific higher layer signaling.

[0163] In order to improve the flexibility of system operation and the reliability of PDCCH transmission, the number of CCE aggregation levels and the number of candidates for each CCE aggregation level for UE monitoring in the common search space can be configured through system information from the gNB. For example, the first system information block can indicate the number of CCE aggregation levels and the number of candidates for each CCE aggregation level in the CSS for PDCCH transmission (e.g., PDCCH transmission scheduling random access response, paging, or PDCCH transmission for transmitting UE group common information such as sending power control commands). The first system information block can schedule a CCE aggregation level from a set of one or more predetermined CCE aggregation levels, or the aggregation level used to schedule the transmission of the first information block can be implicitly or explicitly indicated in the master information block.

[0164] An important goal in the design of the PDCCH search space is to reduce the number of channel estimates that the UE needs to perform in order to decode a PDCCH candidate, as this can directly reduce the required power consumption of the UE modem for decoding the PDCCH candidates in each time slot. This power consumption can correspond to a significant percentage (such as about 50%) of the total UE modem power consumption when the UE is not in a discontinuous reception (DRX) state, since the UE needs to decode the PDCCH in each DL time slot even when the UE is not scheduled for DL ​​reception or UL transmission. The nested structure of the PDCCH search space is one method for reducing the number of channel estimates, where channel estimates obtained for decoding a PDCCH candidate with a first CCE aggregation level can be used to decode a PDCCH candidate with a second CCE aggregation level that is smaller than the first CCE aggregation level, which typically corresponds to the maximum CCE aggregation level.

[0165] Fig.16 An example nested structure of PDCCH candidates 1600 according to an embodiment of the present disclosure is shown. Fig.16 The illustrated embodiment of the nested structure of the PDCCH candidates 1600 is for illustration only. Fig.16One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0166] like Fig.16 As shown, in the PRB set, or in the entire system BW, the UE is configured with M for aggregation level L = 8 CCEs. (8) = 2 candidates 1610, 1615, for M with aggregation level L = 4 CCEs (4) =2 candidates 1620, for M with aggregation level L=2 CCE (2) = 6 candidates 1630, 1635, and for M with aggregation level L = 1 CCE (1) = 6 candidates 1640. For M with L = 8 CCEs (8) = 2 candidate CCE indices can be continuous as in Equation 1 or discontinuous with an offset as defined in Equation 2. The CCE index for the lower CCE aggregation level is M with L = 8 CCEs. (8) = 2 candidate CCE indices. The CCE indices for the lower CCE aggregation level may have a CCE index from M with L = 8 CCEs. (8) = continuous index starting from the index of the first CCE of the first candidate among the two candidates, such as Fig.16 As shown, or can be equally divided to occupy M with L = 8 CCEs (8) = CCE index of each of the 2 candidates, and so on.

[0167] For example Fig.16 A disadvantage of using a nested structure for CCE indices in is that there is an increased probability that a PDCCH cannot be sent to a UE because the associated CCE has an index that at least partially overlaps with a CCE used for a PDCCH transmission to another UE. For example, when CCEs used for a PDCCH transmission to a first UE and CCEs used for a PDCCH transmission to a second UE overlap for candidates using a maximum CCE aggregation level, such an overlap may exist for PDCCH candidates using a smaller CCE aggregation level, and when the PDCCH transmission to the first UE has the maximum CCE aggregation level, there may be only a few candidates and only a small CCE aggregation level available for the PDCCH transmission to the second UE.

[0168] For example, refer to Fig.16 , when the first PDCCH transmission to the first UE needs to use M with L=4 CCEs (4)= 2 candidates, and when the CCE for the first PDCCH candidate with L = 8 CCEs completely overlaps with the CCE for the first PDCCH candidate with L = 8 CCEs for the second UE, the PDCCH transmission to the second UE cannot use most of the remaining candidates for any CCE aggregation level. The increase in blocking probability will basically offset the potential benefits of the nested search space structure on UE power consumption, because the UE needs to stay active for a longer period of time to complete the transmission or reception of data.

[0169] A CCE for PDCCH transmission can be formed by many REGs, where one REG is the same as one RB on one OFDM symbol. Assuming that CCE is the minimum resource unit for DCI format transmission with a given code rate and QPSK modulation, the number of REGs required for CCE depends on the reference DCI format size and the number of SCs in the RB that can be used for DCI format transmission (except for SCs for DMRS transmission). For example, for a DCI format size of 60 bits (or 76 bits including a 16-bit CRC) and a code rate of 2 / 3, 57 SCs are required for DCI format transmission. For 2 DMRS SCs per RB for PDCCH transmission and 12 SCs per RB, a number of approximately 6 REGs (or 6 RBs) is required for CCE. For 4 DMRS SCs per RB for PDCCH transmission and 12 SCs per RB, a number of approximately 7 REGs (or 7 RBs) is required for CCE. PDCCH transmission can be on a variable number of OFDM symbols, such as 1, 2 or 3 OFDM symbols.

[0170] The number of symbols may be configured by signaling from the physical layer or higher layers. To improve spectral efficiency and simplify the design of PDCCH transmissions, design goals in mapping CCEs to REGs or mapping PDCCHs to CCEs may include enabling multiplexing of distributed PDCCH transmissions and centralized PDCCH transmissions in the same PRB set (or control resource set), or making all CCEs equivalent in terms of the SC available for PDCCH transmissions, regardless of whether the PDCCH transmission spans one OFDM symbol or multiple OFDM symbols.

[0171] Therefore, a nested PDCCH search space structure needs to be designed for distributed PDCCH transmission and centralized PDCCH transmission.

[0172] Yet another need is to design a nested PDCCH search space structure with reduced PDCCH blocking probability.

[0173] Yet another need is to define the mapping of CCE to REG and PDCCH to CCE for a nested PDCCH search space over multiple slot symbols.

[0174] In one embodiment, a design of a nested PDCCH search space and a design capable of reducing blocking probabilities of PDCCH candidates at various CCE aggregation levels in the nested PDCCH search space are considered.

[0175] For PDCCH transmission, the associated blocking probability benefits from the PDCCH candidates for different CCE aggregation levels, which typically use different CCE indices. For example, for the PDCCH search space defined in Equation 1, the CCE index of the PDCCH candidate depends not only on the corresponding CCE aggregation level L, but also on the number of candidates per CCE aggregation level L.

[0176] For nested search spaces, the flexibility of the CCE index of the PDCCH candidate according to Equation 1 is greatly reduced because the CCE index needs to be shared among multiple PDCCH candidates with different CCE aggregation levels. In addition, based on Equation 1, the CCE index of different PDCCH candidates with the same CCE aggregation level is deterministic. For example, for the PDCCH search space according to Equation 1, the CCE index of the PDCCH candidate with the same CCE aggregation level is determined by the deterministic factor offset.

[0177] Therefore, when the CCE indices of PDCCH candidates overlap for different UEs and a nested search space structure is used, the probability of a large number of PDCCH candidates overlapping for any CCE aggregation level is greatly increased, and the blocking probability of PDCCH transmission to the UE is thus increased. In the following, it is generally assumed that the CCE aggregation level may also depend on the PRB set, also called control resource set, that the UE is configured for PDCCH reception, and that the symbol L is used. p (instead of L). In addition, assuming that the CCE aggregation level L p is a power of 2, such as L p =2 n , n=0,1,2,...。

[0178] The first implementation manner considers that the CCE index of the PDCCH candidate with a CCE aggregation level smaller than the maximum CCE aggregation level in the control resource set is determined relative to the CCE index of the PDCCH candidate with the maximum CCE aggregation level in the control resource set.

[0179] The first mechanism for reducing the blocking probability of PDCCH transmissions to different UEs is to make the parameter Y in Equation 1 p,kThe determination of randomizes the CCE index of the PDCCH candidate with the maximum CCE aggregation level by relying on the index of the PDCCH candidate in addition to the UE RNTI. Then, for example, when the CCE indexes of the PDCCH candidates with the maximum CCE aggregation level overlap for two UEs, the probability of such overlap of the additional PDCCH candidates with the maximum CCE aggregation level is reduced because the corresponding CCE indexes are randomized according to the UE RNTI.

[0180] For example, for the CCE index determined according to Equation 1 and for the CCE with the maximum CCE aggregation level PDCCH candidates, candidates The CCE index can be determined according to Equation 2:

[0181]

[0182] where the same notations as in Equation 1 apply, and Y p，k，m =(A p，m ·Y p，k-1，m ) mod D provides randomization for different candidates with maximum CCE aggregation levels. p，-1，m =n RNRI ≠0, and for A p，0 =39827 and A p，1 =39831.

[0183] The second mechanism to reduce the blocking probability of PDCCH transmissions to different UEs is to randomize the CCE index of the PDCCH candidates by having a random offset between the last (or first) CCE index of successive PDCCH candidates. The random offset can be a function of the UE RNTI or a function of both the UE RNTI and the PDCCH candidate index.

[0184] For example, for the CCE index determined according to Equation 1 and for the CCE with the maximum CCE aggregation level PDCCH candidates, candidates The CCE index of can be determined according to Equation 3A or Equation 3B:

[0185]

[0186] as well as

[0187]

[0188] where the same notation as in Equation 1 applies, and f(m) is a pseudorandom function with PDCCH candidate m and UERNTIn RNTI≠0 as an independent variable, for example, f(m) = m·n RNRI .

[0189] The first mechanism (different hash functions for different PDCCH candidates) and the second mechanism (UE-specific offset between consecutive PDCCH candidates) may also be combined.

[0190] In Equation 2 or Equation 3A / 3B, since the CCE indices of different PDCCH candidates with the same CCE aggregation level are random and not separated by a predetermined offset as in Equation 1, overlap may occur. p,k,m When the values ​​of at least partially overlap, for example, when they are determined based on Equation 2, an adjustment may be applied to avoid such overlap.

[0191] For example, when the CCE indices of different PDCCH candidates overlap, the UE may reuse the CCE indices determined in the last slot when the CCE indices of different PDCCH candidates do not overlap. For example, when the CCE indices of different PDCCH candidates overlap, the CCE indices of each applicable PDCCH candidate after the first PDCCH candidate may be shifted by a corresponding minimum value to avoid overlapping with previous PDCCH candidates of the same CCE aggregation level. It is also possible to allow overlapping of CCE indices.

[0192] After determining the CCE index in control resource set p for the PDCCH candidate with the maximum CCE aggregation level, the next step is to determine the CCE index for the PDCCH candidate with a CCE aggregation level less than the maximum CCE aggregation level in control resource set p.

[0193] In for In some embodiments of case 1, when the condition Applicable to any CCE aggregation level L p <L p，max When the CCE aggregation level is L p The CCE indices of all PDCCH candidates may be those with CCE aggregation level L p,max A subset of the CCE indices of all PDCCH candidates.

[0194] Determine the CCE aggregation level L p <L p，max The first method of determining the CCE index of the PDCCH candidate is to consider the case with CCE aggregation level L. p,max of Each of the CCE indices of the PDCCH candidates has a CCE aggregation level L p <Lp，max Total PDCCH candidates are distributed equally. p First The candidate CCE index is a CCE aggregation level L p,max A subset of the CCE indices of the first PDCCH candidate. When the CCE aggregation level is L p Second The CCE index of the PDCCH candidate is the CCE aggregation level L p,max A subset of the CCE indices of the second PDCCH candidates. When the CCE aggregation level is L p The third The CCE index of the PDCCH candidate is the CCE aggregation level L p,max A subset of the CCE index of the third PDCCH candidate, and so on. In general, when When the CCE aggregation level is L p The mth The CCE index of the PDCCH candidate is the CCE aggregation level L p,max A subset of CCE indices of PDCCH candidates.

[0195] In determining the CCE aggregation level L p of After PDCCH candidates, the CCE index of the corresponding PDCCH candidate can be determined as shown in Equation 1, where N ECCE,p,k L p,max Then, The CCE index of a PDCCH candidate can be determined according to Equation 4:

[0196]

[0197] In equation 4, it is also possible to use Y p,k,m Instead of Y p,k .

[0198] With CCE aggregation level L p,max The randomization of the CCE indices of the PDCCH candidates can also be extended to PDCCHs with CCE aggregation level L. p <L p，max The CCE index of the PDCCH candidate, as in Equation 2 or Equation 3A / 3B, where instead of considering all CCE indices N in the PDCCH resource set ECCE,p,k , only consider the CCE aggregation level L p,max The CCE index of the corresponding PDCCH candidate.

[0199] Fig.17 An example process 1700 of determining CCEs for PDCCH candidates based on a first implementation of a nested PDCCH search space structure according to an embodiment of the present disclosure is shown. Fig.17 The illustrated embodiment of process 1700 for determining CCE is for illustration only. Fig.17 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0200] like Fig.17 As shown, the UE is configured with a control resource set p by the gNB, and the control resource set p has a number of N ECCE,p,k CCEs, and the CCE aggregation level L in the control resource set p p The number of PDCCH candidates. ECCE,p,k The possible value of and L p The value of may also be determined in the system operation specification or derived by the UE according to some specific formula. p,max PDCCH candidates The CCE index is

[0201]

[0202] Where f(m) is a function of PDCCH candidate m and can also be set to 0 1710. The UE determines that the CCE index is a PDCCH candidate A subset of the CCE index PDCCH candidates 1720. p,max In the CCE set of PDCCH candidate m, the UE determines the CCE set with L p <L p，max PDCCH candidates The CCE index is

[0203]

[0204] Fig.18 An example determination 1800 of CCEs for PDCCH candidates based on a first method of a first implementation of a nested PDCCH search space structure according to an embodiment of the present disclosure is shown. Fig.18 The illustrated embodiment 1800 of determination of CCE is for illustration only. Fig.18One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0205] like Fig.18 As shown, the UE is configured to decode PDCCH candidates corresponding to four CCE aggregation levels of 1, 2, 4, and 8 CCEs. as well as UE determines The first set and the second set of CCE indices of the first PDCCH candidate 1810 and the second PDCCH candidate 1815 in the PDCCH candidate (eg, Equations 2 to 4 may be used as exemplary references). are equally distributed (when is an even number) to use the CCE aggregation level L p,max The CCE index of the first PDCCH candidate (1820, 1830 and 1840) or the CCE index with CCE aggregation level L p,max The CCE indices (1825, 1835 and 1845) of the CCE indices of the second PDCCH candidates.

[0206] Determine the CCE aggregation level L p <L p，max The second method of CCE indexing of PDCCH candidates considers the case with CCE aggregation level L p,max of Each of the CCE indices of the PDCCH candidates has a CCE aggregation level L p <L p，max Total The configuration of the distribution of PDCCH candidates. This configuration can be provided by the gNB through higher layer signaling. For example, for as well as The configuration may indicate a CCE aggregation level L p of The CCE indices of 2 / 3 of the PDCCH candidates are those with CCE aggregation level L. p,max A subset of the CCE index of the first PDCCH candidate with CCE aggregation level L p of The CCE indices of 1 / 3 of the PDCCH candidates are those with CCE aggregation level L. p,max A subset of CCE indices of the second PDCCH candidates.

[0207] The second method enables the gNB to have additional control over the blocking probability of a UE with RNTI, which would otherwise result in an increased blocking probability, especially when controlling the total number of CCEs N in resource set p. ECCE,p,k is not large enough and will result in a CCE aggregation level of L p,max When the CCEs of different PDCCH candidates overlap.

[0208] According to the first implementation, the determination of the CCE indexes of the PDCCH candidates with different CCE aggregation levels takes into account the following for all L p <L p，max , In order to simplify the determination of the CCE index of the nested structure of the PDCCH candidate, it can be assumed that when the nested PDCCH structure is used according to the first implementation mode And the UE may ignore the configuration of the number of PDCCH candidates for the corresponding CCE aggregation level that does not meet the condition, or assume that for L p,max The minimum number of additional virtual candidates such that The UE may also be individually configured by higher layers whether to assume a nested structure of CCEs for PDCCH candidates for different aggregation levels and determine the search space equations for the CCE indices of PDCCH candidates accordingly. The CCE structure of the UE common search space may be defined as having a conventional structure (search space) or a nested structure in the specification of system operation.

[0209] In for (At least one L p <L p，max ) In some embodiments of case 2, when the system operation allows (At least one CCE aggregation level L p <L p，max , such as L p，max =8 and L p，max1 =4), with CCE aggregation level L p，max1 Many PDCCH candidates The CCE index can be independent of the CCE aggregation level L p,max The PDCCH candidate is determined by the CCE index of the PDCCH candidate, and is not a subset of the latter CCE index, but has a CCE aggregation level L p，max1 of The CCE index of a PDCCH candidate can be as follows Determined when.

[0210] In one example, by p，max Replace with L p，max1 , and Replace with right The determination of the CCE index of the PDCCH candidate can be performed as for determining The CCE index of the PDCCH candidates is in one of equations 2, 3A or 3B.

[0211] In one example, to avoid The potential overlap of CCE indices among PDCCH candidates is due to The CCE index of the PDCCH candidate is The CCE indexes of the PDCCH candidates are determined differently, so The determination of the CCEs of the PDCCH candidates can be performed, for example, by considering all PDCCH candidates are as in one of equations 1, and the first one is selected PDCCH candidates are not related to other The CCE indices of the PDCCH candidates overlap with the CCE indices.

[0212] when Also for at least one CCE aggregation level L p，max2 , where L p，max2 <L p，max1 ,(and ), such as L p，max1 =4 and L p，max2 =2, two cases can be considered. The first case is considered In one example, the quantity is The CCE index of a PDCCH candidate can be determined, for example, in Equation 4, and The number can be expressed as L in Equation 4. p，max1 Replaced L p，max And consider the corresponding The set of CCEs for PDCCH candidates is then determined again. p，max2 The determination of the CCE index of the PDCCH candidate takes into account that the maximum CCE aggregation level is L p，max 1(not L max，p ), and Equation 4 can be obtained by using L p，max1 Replace L p，max Applies to all PDCCH candidates.

[0213] This leads to a nested structure for determining CCE indices, where the CCE index of the PDCCH candidate with the maximum CCE aggregation level in control resource set p is first determined from the set of all CCE indices in control resource set p, when When , the CCE index of the PDCCH candidate with the second largest CCE aggregation level in the control resource set p is determined only from the CCE index set of the PDCCH candidate with the largest CCE aggregation level, or otherwise from the CCE index set for The CCE index set of the PDCCH candidates with the maximum CCE aggregation level and the CCE index set of the PDCCH candidates with the maximum CCE aggregation level The CCE index of the PDCCH candidate with the second largest CCE aggregation level in the control resource set p is determined from the two sets of all CCE indices in the control resource set p (as previously described, with possible adjustments to avoid overlapping CCE indices of PDCCH candidates with the same CCE aggregation level), when When , the CCE index of the PDCCH candidate with the third largest CCE aggregation level in the control resource set p is determined only from the CCE index set of the PDCCH candidate with the first largest CCE aggregation level, or otherwise from the CCE index set for The CCE index set of the PDCCH candidates with the second largest CCE aggregation level and the The CCE index of the PDCCH candidate with the third largest CCE aggregation level in the control resource set p is determined from the set of all CCE indices in the control resource set p, and so on.

[0214] In the second case, when (and ), with CCE aggregation level L p，max2 The number of The CCE indices of the PDCCH candidates can be obtained, for example, by using L p，max1 Replace L p，max is determined in Equation 4. This can be done by using L p，max2 Replace L p,max1 If targeted PDCCH candidates determine the number of remaining PDCCH candidates CCE index.

[0215] The second implementation manner considers that the CCE index of the PDCCH candidate is determined relative to the CCE index of the PDCCH candidate requiring the largest number of CCEs.

[0216] The UE first determines the number of PDCCH candidates to be configured in the control resource set p. With CCE aggregation level L p The product value of The maximum value of . The maximum value corresponding to and L p Respectively expressed as and L p，nest . and L p，nest The value of can be different for different control resource sets. p Value exists The same maximum value of L is selected p The value can be multiple L p Any of the values, such as a maximum or minimum value.

[0217] The UE then determines, for example, according to Equation 1 or according to Equation 2 The number of CCEs obtained is For example, referring to Equation 1, the PDCCH candidate The CCE can be determined according to Equation 5:

[0218]

[0219] The UE then uses N CCE，p，k，nest Replace N CCE，p，k And for example, using equation 1 or using equation 2 to determine PDCCH candidate CCE. For example, referring to equation 1, (L p ≠L p，nest ) The CCEs of the PDCCH candidates may be determined as given in Equation 6:

[0220]

[0221] Fig.19 An example determination 1900 of CCEs for PDCCH candidates based on a second implementation according to an embodiment of the disclosure is shown. Fig.19 The illustrated embodiment 1900 of the determination of CCE is for illustration only. Fig.19 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0222] like Fig.19 As shown, the UE is configured by the gNB with a control resource set p, which has a number of N CCE,p,k CCEs and control resource set p have CCE aggregation level L p The number of PDCCH candidates. CCE,p,k The predetermined value and L p The value of may also be determined in the system operating specification, or derived by the UE according to some specific formula. and L p The UE determines the CCE aggregation level for For each of the PDCCH candidates, consider all N CCE，p，k For a set of CCEs, the UE determines a corresponding CCE index 1920 according to a formula (such as, for example, one of Equation 1 or Equation 2).

[0223] for Each of the PDCCH candidates is considered The set of CCE indices of PDCCH candidates is used as the set of available CCE indices, that is, by using Replace N CCE，p，k , the UE determines the corresponding CCE index 1930 according to a formula (such as, for example, one of Equation 1 or Equation 2).

[0224] Fig. 20 An example CCE index 2000 of a PDCCH candidate based on a second implementation manner according to an embodiment of the present disclosure is shown. Fig. 20 The illustrated embodiment of CCE index 2000 is for illustration only. Fig. 20 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0225] like Fig. 20 As shown, the UE has a CCE aggregation level of L p =1 There are 1910 PDCCH candidates, and the CCE aggregation level is L p =2 There are 1920 PDCCH candidates, and the CCE aggregation level is L p =4 There are 1930 PDCCH candidates and the CCE aggregation level is L p =8 There are 1940 PDCCH candidates. Considering all N in control resource set p in time slot k CCE，p，k 1950 CCEs, UE determines that the CCE aggregation level is L p =4 The CCE index forms N CCE，p，k，nest The UE controls resource set p and N in time slot k. CCE，p，k，nest The CCE aggregation level L is determined by the CCE index in the set of CCEs.p =1, L p =2 and L p =8 and The CCE index of the PDCCH candidate.

[0226] As described in relation to the first implementation, the parameter Y in equation 1 can also be p,k The determination of depends not only on the UE RNTI but also on the index of the PDCCH candidate to randomize the CCE index of the PDCCH candidate. Then, for example, for the CCE index corresponding to L p ≠L p，nest The CCE index can be calculated according to Equation 2 or according to Equation 3A / 3B (usually by using L p,nest or L p Replace L p,max ) and use N CCE，p，k，nest Instead of N CCE，p，k To determine the CCE index.

[0227] Furthermore, an additional condition that can be applied to both the first implementation and the second implementation is to use different CCE indices not only for PDCCH candidates with the same CCE aggregation level, but also, where possible, for PDCCH candidates with different CCE aggregation levels. This can be achieved by removing the CCE indices that have been allocated to the PDCCH candidates from the set of available CCE indices and continuing in an iterative manner. For example, from the complete set {S CCE，p，k}, the PDCCH candidates for the CCE aggregation level can be obtained. CCE，p，k，nest For example, according to the first implementation, the CCE aggregation level may be L p,max , or according to the second implementation, the CCE aggregation level can be

[0228] From {S CCE，p，k，nest} In the set CCE index, the CCE aggregation level L can be first determined p,max (When different from L p,nest The CCE index of the PDCCH candidate of time) and from {S CCE，p，k，nest} is removed from the second set of CCE indices to determine {S CCE，p，k，nest，1}. From {S CCE，p，k，nest，1} set CCE, the CCE with the second largest aggregation level L can then be determined p,max1 (When different from L p,nest The CCE index of the PDCCH candidate of time) and from {S CCE，p，k，nest，1} is removed from the second set of CCE indices to determine {S CCE，p，k，nest，2}, and so on. This process may continue until the CCE indices of all PDCCH candidates of all CCE aggregation levels are allocated, or until the set of available CCE indices does not include enough CCE indices to allocate to PDCCH candidates of CCE aggregation levels without overlap. In the latter case, the first set of CCE indices {S CCE，p，k，nest} to reinitialize the process.

[0229] The second embodiment of the present disclosure considers mapping of CCE to REG and mapping of PDCCH to CCE considering nested PDCCH search space.

[0230] When the UE is configured with PDCCH candidates that are mapped to a variable number of OFDM symbols (such as the first OFDM symbol or all OFDM symbols of a DL control resource set in a slot), or mapped to different OFDM symbols (such as the first OFDM symbol or the second OFDM symbol), the number of CCEs available for mapping the PDCCH candidates may depend on the number of respective OFDM symbols used for mapping. For example, the number of CCEs available for mapping PDCCH candidates on two OFDM symbols may be twice as large as the number of CCEs available for mapping PDCCH candidates on one OFDM symbol.

[0231] This effectively creates multiple control resource subsets within one control resource set, where the control resource subsets can be identified by the number or index of associated OFDM symbols, and all control resource subsets span the same BW as the control resource set. When all PDCCH candidates are mapped to all OFDM symbols of the control resource set (which is usually the case when the control resource set includes only one OFDM symbol), a nested search space can be obtained, as described in the aforementioned embodiments of the present disclosure.

[0232] Fig.21 An example control resource subset 2100 of a set of control resources is shown according to an embodiment of the present disclosure. Fig.21 The illustrated embodiment of control resource subset 2100 is for illustration only. Fig.21 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0233] like Fig.21As shown, the UE is configured with PRB sets 2110A and 2110B of control resource sets spanning two OFDM symbols. The set of PRBs may include PRBs that are contiguous or discontinuous in frequency. The first control resource subset includes all PRBs 2120 in the first OFDM symbol, the second control resource subset includes all PRBs 2130 in the second OFDM symbol, and the third control resource subset is the same as the control resource set and includes all PRBs in both the first OFDM symbol and the second OFDM symbol.

[0234] for Fig.21 In an exemplary implementation of a control resource subset in the first control resource subset, the number of CCEs in the first control resource subset is represented by N CCE，p，k，1 , the number of CCEs in the second control resource subset is denoted as N CCE，p，k，2 , and the number of CCEs in the control resource set is denoted as N CCE，p，k For example, N CCE，p，k，1 =N CCE，p，k，2 =N CCE，p，k / 2.

[0235] The nested search space structure when different PDCCH candidates are mapped to different OFDM symbol indices (including different numbers of OFDM symbols) can be determined as follows. p The DL control resource set p of OFDM symbols, the CCE aggregation level L when CCE is mapped on j OFDM symbols p Indicated as L p，j , and the CCE aggregation level mapped to j OFDM symbols is L p The number of PDCCH candidates is expressed as For the purpose of defining the nested search space structure, it is assumed that the CCEs of the PDCCH candidates are equally distributed over j OFDM symbols and For example, when L p，1 =4, L p，2 =2, L p，3 =2, and L p，4 = 1. Alternatively, only j·L p，j / (j+1), 1≤j≤N p Integer values ​​of can be considered, then when L p =2 l L is not defined p，3 , l is a non-negative integer.

[0236] The UE first determines that for 1≤j≤N p of The maximum value of the product value and set When there is When there are multiple values ​​for or the smallest j nest A value of . Usually, it can be expected that j nest Equal to 1≤j≤N p The minimum value of Right now

[0237] Then, the UE determines, for example, according to Equation 1 or Equation 2: The CCE index of each PDCCH candidate. When each OFDM symbol has the same number of CCEs, The CCE index of the PDCCH candidate may be relative to the CCE index N in the first OFDM symbol of the DL control resource set p in time slot k. CCE，p，k，1 to determine, and the remaining j nest The CCEs in the first OFDM symbol may have the same index as in the first OFDM symbol. In addition, CCE indexing may be per symbol, rather than across all symbols.

[0238] The obtained set of CCE indexes includes the number For example, referring to Equation 1, the PDCCH candidate in the first OFDM symbol of DL control resource set p in time slot k is The set of CCE indices can be determined according to Equation 7:

[0239]

[0240] The UE then uses The set of CCE indices replaces N in the first OFDM symbol of DL control resource set p in time slot k CCE，p，k，1 The set of CCE indices and use Equation 1 or Equation 2 to determine The CCE index of the PDCCH candidate. For example, referring to Equation 1, PDCCH candidates The CCE index can be determined according to Equation 8:

[0241]

[0242] Fig. 22 Example CCE indices 2200 of PDCCH candidates spanning one or two OFDM symbols in a nested structure according to an embodiment of the present disclosure are shown. Fig. 22 The illustrated embodiment of the CCE index 2200 is for illustration only. Fig. 22One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0243] like Fig. 22 As shown, the UE is configured with a DL control resource set p spanning two symbols. p =1 and L p = 2 all PDCCH candidates span one OFDM symbol and for L p =4 and L p =4 PDCCH candidates span two OFDM symbols. The UE is configured with the following PDCCH candidates: and the second OFDM symbol The first OFDM symbol and the second OFDM symbol and because Therefore, the UE determines the first OFDM symbol 2210 according to equation 7, for example. For example, the CCE aggregation level in the first OFDM symbol is L p The first, second, third, fourth, fifth, and sixth PDCCH candidates with PDCCH=2 may use CCEs (1,7), (2,8), (3,9), (4,10), (5,11), and (6,12), respectively.

[0244] Notice that Fig. 22 The actual indices of CCEs 1 to 12 in the DL control resource set may be different, but they are N CCE，p，k，1 =Index in a set of 12 CCEs. For the remaining PDCCH candidates, the CCE index can be obtained from N using, for example, Equation 8. CCE，p，k，1 =12, and CCE 1, 4, 7, and 10 can be used for the corresponding PDCCH candidates, CCE 2 and 8 can be used for the corresponding PDCCH candidates, CCE (2, 8) and (5, 11) can be used for the corresponding PDCCH candidates, CCE (3,9) and (6,12) on two OFDM symbols can be used for the corresponding PDCCH candidates, and CCEs (1,7), (3,9), (4,10) and (6,12) on two OFDM symbols can be used PDCCH candidates.

[0245] The nested PDCCH search space structure may be primarily applicable to distributed PDCCH transmissions, where blocks of one or more REGs of CCEs may be distributed in frequency, and PDCCH candidates may share a set of CCE indices. For localized PDCCH transmissions, where REGs (and CCEs) of PDCCH candidates are contiguous in frequency, the nested search space structure is more difficult to implement when the CCEs of PDCCH candidates are distributed in frequency in order to increase the likelihood of selecting a CCE where the UE experiences favorable channel conditions. For example, for a DL control resource set spanning one OFDM symbol, and for a UE with CCE aggregation level L p =1 PDCCH candidates and for a PDCCH with CCE aggregation level L p =2 PDCCH candidates, even if All PDCCH candidates The CCE index can be PDCCH candidates A subset of CCE indices, which would also require L p =1 and the CCEs of the two PDCCH candidates with L p = 1, and this reduces the possibility of selecting a CCE where the UE experiences favorable channel conditions for PDCCH transmission.

[0246] The limitation of the nested search space design for localized PDCCH transmissions can be addressed by limiting the use of the nested search space to distributed PDCCH transmissions only and using an unconstrained search space design for localized PDCCH transmissions, e.g., as in Equation 1. However, in order for the UE to also benefit from the reduction in the number of channel estimates that the UE needs to calculate per slot, it is possible to apply the nested search space design for localized PDCCH transmissions as well.

[0247] In the first method, for centralized PDCCH transmission, the nested search space design can have a nested allocation of CCEs for PDCCH candidates, where the CCE indices for the CCE aggregation level with the smallest number of candidates overlap with the CCE indices for the CCE aggregation level with the second smallest number of candidates, the CCE indices for the CCE aggregation level with the second smallest number of candidates overlap with the CCE indices for the CCE aggregation level with the third smallest number of candidates, and so on.

[0248] In the second method, for distributed transmission, the CCE index can be determined, and it is possible for some PDCCH candidates to have consecutive CCEs in the frequency domain.

[0249] When the DL control resource set includes multiple OFDM symbols, it is possible to limit the PDCCH candidates for a larger CCE aggregation level (such as 4 CCEs or 8 CCEs) to multiple OFDM symbols in order to limit the frequency span of the PDCCH candidates and reduce the number of RBs that the UE needs to obtain channel estimates. A PDCCH candidate for a smaller CCE aggregation level (such as one CCE) may have corresponding REGs on only one OFDM symbol or on multiple OFDM symbols.

[0250] Furthermore, transmission of localized PDCCH candidates may be configured to span all OFDM symbols regardless of the CCE aggregation level, whereas transmission of distributed PDCCH candidates may span all OFDM symbols of one OFDM (especially for smaller CCE aggregation levels) or DL ​​control resource set (especially for larger CCE aggregation levels).

[0251] Fig.23 An example nested allocation 2300 of allocating CCE indices to PDCCH candidates based on an ascending order of the PDCCH candidates according to an embodiment of the present disclosure is shown. Fig.23 The illustrated embodiment of the nested allocation 2300 of CCE indices is for illustration only. Fig.23 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0252] like Fig.23 As shown, the UE is configured with a DL control resource set p spanning one symbol. p =1 PDCCH candidates with CCE aggregation level L p =2 PDCCH candidates with CCE aggregation level L p =4 PDCCH candidates, and with CCE aggregation level L p =8 PDCCH candidates. The UE may first determine the PDCCH candidate with the largest number according to Equation 1, for example. The CCE index of the CCE aggregation level is 2310. The UE uses The set of CCEs of PDCCH candidates can be calculated by using, for example, Equation 1 (where L p =1) Get One CCE index for each of the PDCCH candidates, and The other CCE index of each of the PDCCH candidates is determined as the corresponding subsequent (or previous) CCE index to determine the The CCE index 2320 of the PDCCH candidate.

[0253] UE uses The set of CCEs of PDCCH candidates can be calculated using, for example, Equation 1 (where L p =1) Get A CCE index of a PDCCH candidate, and The other three CCE indices of each of the PDCCH candidates are determined as the corresponding previous three (or next three) CCE indices to determine the CCE index for The UE uses the CCE indices 2330 and 2335 for the PDCCH candidates. The set of CCEs of PDCCH candidates can be calculated by using, for example, Equation 1 (where L p =1) Get The CCE index of the PDCCH candidate is determined, and the other 7 CCE indexes are determined as the following 7 (or previous 7) CCE indexes to determine the CCE index for the PDCCH candidate. CCE indices of PDCCH candidates 2340. When there are not enough number of subsequent (or previous) CCE indices, previous (or subsequent, respectively) CCE indices may be used.

[0254] Fig.24 An example nested allocation 2400 of assigning CCE indices to PDCCH candidates based on a restriction of CCE indices for a number of PDCCH candidates according to an embodiment of the present disclosure is shown. Fig.24 The illustrated embodiment of the nested allocation 2400 of CCE indices is for illustration only. Fig.24 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0255] like Fig.24 As shown, the UE is configured with a DL control resource set p spanning one symbol. p =1 PDCCH candidates with CCE aggregation level L p =2 PDCCH candidates with CCE aggregation level L p =4 PDCCH candidates, and with CCE aggregation level L p=8 PDCCH candidates. The UE may first determine, for example, according to Equation 1, that the CCE aggregation level is The UE uses the CCE indexes 2410 and 2415 for The set of CCEs of PDCCH candidates can be calculated by using, for example, Equation 1 (where L p =1) Get A CCE index for each of the PDCCH candidates is determined The CCE indices 2420 of the PDCCH candidates.

[0256] UE is used for The set of CCEs of PDCCH candidates can be calculated by using, for example, Equation 1 (where L p =2) Get The two CCE indices of the PDCCH candidates are The other two CCE indices of each of the PDCCH candidates are determined as the corresponding previous two (or next two) CCE indices to determine the The UE uses the CCE index 2430 for the PDCCH candidate. The CCE set of PDCCH candidates can be calculated by using, for example, Equation 1 (where L p =2) Obtain The two CCE indices of the PDCCH candidates are determined, and the other six CCE indices are determined as the following six (or the previous six) CCE indices to determine the CCE indices of PDCCH candidates 2440. When there are not enough number of subsequent (or previous) CCE indices, previous (or subsequent, respectively) CCE indices may be used.

[0257] UL DMRS or SRS transmission may be based on the transmission of a Zadoff-Chu (ZC) sequence, a CAZAC sequence, or a pseudo noise (PN) sequence. UL system BW of RBs, ZC sequence Can be based on base sequence is defined by the cyclic shift (CS) α of is the sequence length, as well as The qth root ZC sequence is given by where q is defined by Given, and Depend on Given. The length of the ZC sequence By making The largest prime number of is given.

[0258] Multiple RS sequences can be defined from a single base sequence using different α values. UL DMRS or SRS transmissions can have a comb spectrum where non-contiguous SCs are used for transmission in a slot symbol. SRS transmissions are identified by a set of corresponding parameters, such as a transmission comb, cyclic shift, BW, starting position in the system BW, number of transmit antenna ports, timing offset of the first transmission, or number of transmission symbols.

[0259] CSI-RS can be transmitted on a certain number of antenna ports, such as one, two, four, eight, twelve, or sixteen antenna ports. For CSI-RS using more than eight antenna ports, CSI-RS configurations are aggregated to obtain a total antenna ports. Each CSI-RS configuration in this aggregation corresponds to The LTE specification describes the mapping of CSI-RS to REs in a time slot.

[0260] Multiple CSI-RS configurations may be used in a cell. A UE may be configured with multiple CSI-RS sets, including configurations of up to three NZP CSI-RS that the UE may use for CSI reporting, and configurations of zero or more ZP CSI-RS. The NZP CSI-RS configuration is provided by higher layers. The ZP CSI-RS configuration in a slot may be given by a derived bitmap.

[0261] The UE may be configured with one or more CSI-RS resource configurations that may include the following parameters. In one example, the one or more CSI-RS resource configurations include a CSI-RS resource configuration identity. In another example, the one or more CSI-RS resource configurations include the number of CSI-RS ports. For example, the allowed values ​​and antenna port mapping may be as described in the LTE specification. In yet another example, the one or more CSI-RS resource configurations include a CSI-RS configuration described in the LTE specification. In yet another example, the one or more CSI-RS resource configurations include a CSI feedback P of the UE for each CSI process. c The reference PDSCH transmit power assumption. When the CSI time slot set C CSI,0 and C CSI,1 When configured by higher layers for CSI processes, P c Each CSI time slot set configured for a CSI process. In yet another example, one or more CSI-RS resource configurations include a pseudo-random sequence generator parameter n IDIn yet another example, if the UE is configured with a higher layer parameter eMIMO-Type, and the eMIMO-Type is set to "CLASS A" for the CSI process as described in the LTE specification, then one or more CSI-RS resource configurations include a CDM type parameter.

[0262] A UE may be configured with one or more CSI resource configurations for interference measurement (CSI-IM). It is generally not desirable for a UE to receive a CSI-IM resource configuration that does not completely overlap with one of the ZP CSI-RS resource configurations.

[0263] Based on the calculation of the CQI, the UE may derive a CQI index between 1 and 15 corresponding to a transport block size and a modulation scheme that the UE can receive with a BLER not exceeding a predetermined value (such as 10%). If this is not possible, the UE reports a CQI index of 0. Table 1 gives an explanation of the CQI index, and there may also be different mapping tables.

[0264] Table 1. 4-bit CQI table for conventional UEs

[0265]

[0266]

[0267] The network may support UEs with different transmit or receive BW capabilities. For example, the network may have an available system DL BW or UL BW of 200 MHz, while a certain class of UEs may be capable of or configured to receive or transmit only in a BW smaller than the system DL BW or UL BW, such as in 20 MHz. Although the UE's transmit BW or receive BW is smaller than the system's DL BW or UL BW, respectively, the gNB may schedule reception or transmission from the UE in any portion of the respective system BW.

[0268] The gNB can configure the UE narrowband (NB) of the DL system BW or UL system BW (where the BW of each NB does not exceed the UE's receive BW or transmit BW capability) and schedule transmissions to or from the UE in each NB. The NBs can have the same or different sizes. For example, all NBs can have the same size except that the last NB can have the same or smaller size than the other NBs.

[0269] The term narrowband is used as a reference, and any other term such as subband or BW portion may be used instead to represent the partitioning unit of the system BW into smaller BWs. Furthermore, the NBs may be non-overlapping, or may partially overlap.

[0270] The DL DCI format or UL DCI format for scheduling transmissions to or from the UE, respectively, may include a first field indicating the NB and a second field indicating resources within the NB. It is also possible that the NB and the PRB allocation within the NB are indicated by a single field. In order for the gNB to select a NB from a set of NBs for scheduling reception or transmission from the UE while improving the system spectrum efficiency, the gNB needs to provide CSI for NBs from the set of NBs from the UE. The UE may provide the gNB with CSI reports for NBs from the set of NBs by sending CSI reports for the NBs or by sending SRS in the NB to the gNB. The UE may send CSI reports in the PUCCH or PUSCH in resources configured by the gNB through higher layer signaling or through the physical layer (L1).

[0271] The UE can obtain a CSI report for a NB by measuring the CSI-RS transmitted in the NB. This requires the UE to re-tune the UE's radio frequency (RF) receiver to the NB in ​​order to receive the CSI-RS. Since the NB used for CSI-RS reception may be different from the NB in ​​which the UE is configured to receive the PDCCH, this requires two re-tuning operations; one from the NB configured for PDCCH reception to the NB for CSI-RS transmission, and the other from the NB for CSI-RS transmission to the NB for PDCCH transmission. Since the RF re-tuning operation of the UE receiver requires a period of time in which the UE cannot receive signaling, this may limit the UE's scheduling opportunities and limit the data rate achievable by the UE. Therefore, it is beneficial to reduce the time that the UE is unable to receive DL control channels due to the re-tuning operation.

[0272] For SRS transmission from a UE at a BW greater than the maximum SRS transmission BW that the UE can support, the UE may transmit SRS in different NBs of the BW during respective different opportunities. In addition, the UE capability for receiving from many antennas simultaneously may be greater than the UE capability for transmitting from many antennas simultaneously. For TDD systems, due to the mutual DL BW and UL BW, the SRS transmission from the UE may provide CSI for DL ​​transmission to the UE, so it is beneficial to enable SRS transmission from all UE antennas.

[0273] Therefore, the gNB is required to trigger CSI-RS transmission in different narrowbands at different times.

[0274] The UE is also required to measure the CSI-RS in different narrowbands at different times.

[0275] The UE is also required to provide CSI reports for different narrowbands.

[0276] Yet another need is to configure the UE with resources for transmission of CSI reports.

[0277] There is also a need to reduce the impact of RF re-tuning on UE scheduling.

[0278] Finally, it is also necessary to enable the UE to send SRS in different narrowbands.

[0279] In one embodiment, a design for triggering CSI-RS transmission on multiple NBs is considered. The CSI-RS transmission in the NB can be precoded or not precoded. In the former case, the precoding can also be configured to the UE and can be the same for all NBs (single configuration for all NBs) or different for different NBs (separate configuration for each NB). The CSI-RS transmission can include zero power CSI-RS and non-zero power CSI-RS.

[0280] In order for the UE to receive CSI-RS from NBs in the configured NB set, the UE needs to re-tune the UE's RF receiver component to each NB from the NB set. Depending on whether the NBs in the NB set are in the same frequency band or in different frequency bands, and depending on the slot duration and the UE re-tuning capabilities, the associated RF re-tuning delay may vary from one or a few symbols of a slot to one or more slots. While the UE is re-tuning the UE's receiver RF, the UE cannot receive other signaling from the gNB. Therefore, the CSI-RS transmission in the slot needs to take into account the re-tuning delay while enabling the UE to be scheduled for DL ​​or UL transmission via PDCCH reception in the NBs that the UE is configured to receive PDCCH.

[0281] When the retuning delay is less than the time interval between the last time slot symbol in which the UE is configured to receive PDCCH in the first NB and the first time slot symbol of CSI-RS transmission in the second NB, after receiving PDCCH in the first NB, the UE can receive CSI-RS in the second NB when the UE does not receive other signaling (such as PDSCH in the first NB and in the first time slot or the second time slot).

[0282] When the retuning delay is less than the time interval between the last time slot symbol for receiving CSI-RS in the second NB and the first time slot symbol for receiving PDCCH in the first NB, after receiving CSI-RS in the second NB, the UE may re-tune to the first NB to receive PDCCH. When the UE detects a PDCCH that schedules the UE to receive PDSCH in the first NB, and the UE is also configured to receive CSI-RS in the second NB, and the time between the end of PDSCH reception and the start of CSI-RS reception is less than the retuning delay from the first NB to the second NB, the UE may abandon reception of CSI-RS.

[0283] For a TDD system and a UE with a single duplexer, when the UE is configured to send a random access channel, or PUSCH, or PUCCH (such as a PUCCH conveying HARQ-ACK) in a first NB, and the UE is also configured to receive CSI-RS in a second NB, and the retuning delay is greater than the time between the end of UL signaling and the start of CSI-RS reception, the UE may abandon reception of CSI-RS. For a TDD system and a UE with a single duplexer, when the UE is configured to send SRS in a NB, and the UE is also configured to receive CSI-RS in a different NB, and the retuning delay prevents the UE from sending SRS or receiving CSI-RS, the UE may prioritize reception of CSI-RS and abandon transmission of SRS. The UE may report the last valid CSI-RS measurement for the NB for which the UE abandoned CSI-RS reception.

[0284] In one example, CSI-RS transmissions in a set of one or more NBs may be semi-continuous or periodic. The UE is configured by a higher layer with the set of NBs and parameters for CSI-RS transmissions in each NB in ​​the set of NBs. Each NB in ​​the set of NBs has a respective index determined, for example, according to an ascending order in the system BW. CSI-RS transmissions may also occur according to an ascending order of the NB indexes, except for CSI-RS transmissions in NBs in which the UE may be configured to receive PDCCH, as discussed further below, where CSI-RS transmissions may occur first. The CSI-RS transmission parameters may be the same for all NBs and may be configured jointly for all NBs, except for the position of the time slot symbol for the CSI-RS transmission, as discussed further below, or may be configured separately for each NB.

[0285] As mentioned above, the CSI-RS transmission parameters may include the CSI-RS resource configuration identity, the number of CSI-RS ports, the CSI-RS configuration, the reference P for each CSI process, and the CSI-RS resource configuration identity. c power, pseudo-random sequence generator parameters, n ID and one or more of the CDM type parameters. The CSI-RS transmission parameters may also include the reference slot and periodicity of CSI-RS transmission in each NB, the number of symbols of CSI-RS transmission in a slot, or a CSI process identity.

[0286] Fig.25 An example CSI-RS transmission 2500 among a number of NBs is shown, wherein the UE re-tunes to the NB for which the UE is configured for PDCCH reception after receiving the CSI-RS transmission, according to an embodiment of the disclosure. Fig.25 The illustrated embodiment of CSI-RS transmission 2500 is for illustration only. Fig.25One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0287] like Fig.25 As shown, the UE is configured with a NB set including four NBs, and resources in a first NB from the four NBs are used for PDCCH reception. In a first time slot, the UE receives PDCCH 2510 in the first NB and receives CSI-RS transmission 2515 in the first NB. In a second time slot, the UE receives PDCCH 2520 in the first NB, re-tunes to the second NB to receive CSI-RS transmission 2525, and re-tunes back to the first NB in ​​a third time slot to receive PDCCH. In a third time slot, the UE receives PDCCH 2530 in the first NB, re-tunes to the third NB to receive CSI-RS transmission 2535, and re-tunes back to the first NB in ​​a fourth time slot to receive PDCCH.

[0288] In the fourth time slot, the UE receives PDCCH 2540 in the first NB, re-tunes to the fourth NB to receive CSI-RS transmission 2545, and re-tunes back to the first NB to receive PDCCH in the fifth time slot. Re-tuning to a NB other than the currently active NB at which the UE receives PDCCH in a time slot may be conditioned on the UE not having reception in the currently active NB in ​​that time slot. Fig.25 It is considered that CSI-RS transmission for UE in each NB occurs with the same periodicity, but different periodicities are also possible, for example, the periodicity of CSI-RS transmission in the first NB is smaller than the periodicity of CSI-RS transmission in other NBs in the NB set.

[0289] Instead of the UE re-tuning to the NB that the UE is configured for PDCCH reception, the UE may be configured to re-tune to the NB of the next CSI-RS transmission. For example, when the slot includes fourteen symbols, the re-tuning delay is one symbol, and the last symbol for PDCCH reception in the slot is the third symbol, the UE may receive CSI-RS in all NBs before re-tuning to the NB that the UE is configured to receive PDCCH.

[0290] Whether the UE retunes to a new NB to receive a CSI-RS transmission, or to a configured NB to receive a PDCCH, may depend on the time required for the UE to retune between NBs (the retuning delay), the number of NBs in the set of NBs with CSI-RS transmissions, or the timeslot duration, or the maximum duration of the PDCCH transmission.

[0291] When the UE retuning time, slot duration, and maximum duration of transmission of DL control channels are such that the UE can receive CSI-RS transmissions in a subset of the set of NBs before retuning to a NB configured for PDCCH reception, and then retuning to a different subset of the set of NBs for reception of their respective CSI-RS transmissions, relative to Fig.25 and Fig.26 Intermediate behaviors are also possible.

[0292] Fig.26 An example CSI-RS transmission 2600 among a number of NBs is shown, wherein the UE re-tunes to each NB configured for reception of CSI-RS transmissions before re-tuning to the NB configured for PDCCH reception, in accordance with an embodiment of the present disclosure. Fig.26 The illustrated embodiment of CSI-RS transmission 2600 is for illustration only. Fig.26 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0293] like Fig.26 As shown, the UE is configured with a NB set including three NBs, and resources in a first NB from the three NBs are used for PDCCH reception. In a first time slot, the UE receives a PDCCH 2610 and a first CSI-RS transmission 2620 in the first NB. The UE then re-tunes to the second NB to receive a CSI-RS transmission 2630, and then re-tunes to the third NB to receive a third CSI-RS transmission 2640. After receiving the CSI-RS transmissions in the three NBs, the UE re-tunes to the first NB in ​​a second time slot to receive a PDCCH 2650.

[0294] In another example, CSI-RS transmissions in NBs of the NB set may be aperiodic and triggered by a DCI format conveyed by PDCCH.The DCI format may be a DL DCI format that schedules PDSCH transmissions to the UE, or may be a separate DCI format with content for one or more UEs.

[0295] When the DCI format that triggers CSI-RS transmission in one or more NBs in the NB set is a DL DCI format that schedules PDSCH transmission to the UE in one or more time slots, the DL DCI format may include a field indicating one or more NBs in the NB set for CSI-RS transmission. Because the DL DCI format schedules PDSCH transmission to the UE, when the NB of the PDSCH transmission is also the NB with the triggered CSI-RS transmission, in order to be able to receive the PDSCH, the first CSI-RS transmission may occur in the NB in ​​which the UE is configured to receive the PDSCH, and subsequent CSI-RS transmissions occur in the remaining NBs according to the ascending (or descending) order of the NB index.

[0296] When the NB at which the UE is configured to receive the PDCCH is not the NB with the triggered CSI-RS transmission, the UE may receive the PDCCH in one or more time slots and then re-tune to the NB with the triggered CSI-RS transmission after the one or more time slots. It is also possible that the CSI-RS transmissions in the NBs are according to the NB index in ascending order, including the NB for the scheduled DL data channel transmission when the CSI-RS transmission is triggered. Depending on the re-tuning delay, the UE may also receive the PDCCH in the NB in ​​the next time slot before re-tuning, and when the UE detects another DL DCI format in the next time slot that schedules the PDCCH transmission to the UE in the first NB in ​​one or more next time slots, the UE may ignore the triggered CSI-RS transmissions in NBs other than the first NB in ​​one or more next time slots.

[0297] The field of the DL DCI format that triggers CSI-RS transmission in one or more NBs in the NB set configured by the UE may include an indication of the NB. For example, a field with two binary elements (bits) may use a "00" value to indicate no CSI-RS transmission, and use "01", "10" and "11" values ​​to indicate CSI-RS transmission in the first, second or third configured NB subsets in the NB set, respectively. The parameters of the CSI-RS transmission in each NB may be the same or different. As previously mentioned, it is also possible to use a separate field to indicate the NB used for CSI-RS reception, and use the field that triggers CSI-RS reception to indicate the CSI-RS configuration.

[0298] For example, CSI-RS resource configuration identity, number of CSI-RS ports, CSI-RS configuration, reference P for each CSI process c power, pseudo-random sequence generator parameters, n ID, CDM type parameters, the number of symbols in a slot, or the CSI process identity may be the same for all NBs. The position of the slot symbols used for CSI-RS transmission in each NB may be the same or different. For example, when the CSI-RS transmissions are in different slots in respective different NBs, the respective slot symbols may be the same. For example, when the CSI-RS transmissions in at least some NBs are in the same slot, the respective slot symbols are different, and the corresponding offsets of multiple symbols for consecutive CSI-RS transmissions may be determined from the retuning delay of the UE with the associated triggered CSI-RS transmission, or may be signaled by the gNB through UE-common higher layer signaling such as system information or through UE-specific higher layer signaling.

[0299] A DL DCI format that schedules DL data channel transmissions to a UE and triggers the UE to receive corresponding CSI-RS transmissions in one or more NBs in a set of NBs may also trigger a PUCCH transmission from the UE conveying a CSI report for one or more NBs. The resources used for the PUCCH transmission may be explicitly indicated in the DL DCI format or may be configured to the UE via higher layer signaling.

[0300] In a first example, the DL DCI format may include a PUCCH resource allocation field for CSI reporting.The UE may be configured with four PUCCH resources by higher layers, and the PUCCH resource allocation field for CSI reporting may include two bits to indicate one of the four configured resources.

[0301] In a second example, the DL DCI format may include a PUCCH resource allocation field for a HARQ-ACK report associated with the UE's reception result of a DL data channel. For example, the UE may be configured with four PUCCH resources by a higher layer, and the PUCCH resource allocation field for the HARQ-ACK report may include two bits to indicate one of the four configured resources. The PUCCH resources for CSI reporting may then be derived from the PUCCH resources for HARQ-ACK reporting. The UE may also be configured with four PUCCH resources for CSI reporting by a higher layer, and, for example, when the third PUCCH resource is indicated for HARQ-ACK reporting, the UE also uses the third PUCCH resource for CSI reporting. Therefore, the PUCCH resources for HARQ-ACK reporting and CSI reporting are different, but are jointly indicated.

[0302] The same method can be applied to the transmission timing of HARQ-ACK reports and CSI reports. For example, in order to avoid sending a first PUCCH conveying a HARQ-ACK report and a second PUCCH conveying a CSI report from the UE at the same time, the UE can send the CSI report in the next time slot or a predetermined time slot after the time slot in which the UE sends the CSI report. The UE can also be configured to send consecutive PUCCHs in different symbols of the same time slot. The DL DCI format may also include a TPC command for the UE to adjust the PUCCH transmission power for the HARQ-ACK report, and assuming that the closed-loop power control process for the PUCCH transmission is the same, the UE also applies the TPC command to adjust the PUCCH transmission power for the CSI report.

[0303] When the DCI format that triggers CSI-RS transmission for a UE in a NB in ​​the NB set is not a DL DCI format, the DCI format may have the same size as the DL DCI format decoded by the UE, or the same size as the DCI format decoded by the UE for other purposes (such as for obtaining TPC commands). The CRC of the DCI format may be scrambled with an RNTI (such as CSI-RS-RNTI) specific to triggering CSI-RS transmission. The DCI format with CSI-RS-RNTI is referred to as DCI format T for brevity. Using DCI format T, for each UE in the group of UEs configured with the same CSI-RS-RNTI, the gNB may trigger CSI-RS transmission in a different NB in ​​the configured NB set, and possibly also in a different cell.

[0304] The UE may be configured with a position in DCI format T via the parameter Index-CSI-RS, at which the UE may obtain a CSI-RS triggering field indicating CSI-RS transmission in a subset of NBs in the configured NB set. For example, as described for the DL DCI format, the CSI-RS triggering field may have two bits, or, to increase granularity, a larger number of bits than in the DL DCI format, where a value of "00" may indicate no CSI-RS transmission, and the remaining values ​​may indicate CSI-RS transmission in each configured NB subset (including all NBs in the NB set).

[0305] The increased granularity is useful, for example, when there are a large number of NBs in the NB set, or when a UE may be triggered for CSI-RS transmission in multiple NBs and multiple cells or in multiple time slot sets. Alternatively, DCI format T may include separate CSI-RS triggering fields for NB sets on different cells for the same UE. It is also possible that when the CSI-RS triggering field triggers CSI-RS transmission, it does so for all NBs in the NB set. The CSI-RS triggering field may then include a single bit for each UE in each cell, where a value of "0" indicates no CSI-RS triggering, and a value of "1" indicates CSI-RS triggering in all NBs in the NB set.

[0306] DCI format T may also include a field indicating a PUCCH resource for a PUCCH transmission from a UE conveying a CSI report in response to measurements associated with a triggered CSI-RS transmission in a NB in ​​the configured set of NBs, and a field conveying a TPC command for the PUCCH transmission. The PUCCH resource field may be an index to a PUCCH resource in the configured set of PUCCH resources.

[0307] For example, when the PUCCH resource field includes two bits, the PUCCH resource field may indicate one of four configured PUCCH resources. The position of the PUCCH resource field or the position of the TPC command field may be linked to the configured position of the CSI-RS trigger field, for example, the PUCCH resource field may be at the next position, and the TPC command field may be at a position after the next position (or vice versa or at a previous position).

[0308] DCI format T may also indicate a single PUCCH resource for conveying a PUCCH transmission of a CSI report associated with a first position, where the CSI-RS trigger field in DCI format T in the first position does not have a "00" value, and the PUCCH resources for conveying PUCCH transmissions of other CSI reports may be determined relative to the indicated PUCCH resource.

[0309] For example, a UE having a first position for a CSI-RS transmission trigger field with a value other than "00" in DCI format T can use the indicated first PUCCH resource to send a PUCCH conveying a CSI report, a UE having a second position for a CSI-RS transmission trigger field with a value other than "00" in DCI format T can use a second PUCCH resource after the first PUCCH resource, a UE having a third position for a CSI-RS transmission trigger field with a value other than "00" in DCI format T can use a third PUCCH resource after the second PUCCH resource, and so on.

[0310] Therefore, when PUCCH resource n is indicated in DCI format T PUCCH When the nth CSI-RS UEs with CSI-RS transmission trigger values ​​can use PUCCH resource n PUCCH +n CSI-RS -1 to send a CSI-RS report, or by assigning index "0" (instead of index "1") to the first CSI-RS transmission trigger value different from "00", with an nth CSI-RS UEs with CSI-RS transmission trigger values ​​can use PUCCH resource n PUCCH +n CSI-RS The CSI report from the UE may be a combined CSI report for each NB with triggered CSI-RS transmission, or the UE may select a predetermined number of NBs from among the NBs with triggered CSI-RS transmission to provide respective CSI reports.

[0311] The DL DCI format or DCI format T may also include a TPC command field for the UE to adjust the power of the PUCCH transmission that conveys the CSI report. The TPC command field may be adjacent to the CSI-RS transmission trigger field (before or after), or may be located in a different configuration position for each UE. The UE may be configured with more than one CSI-RS-RNTI, where the content of DCI format T is interpreted based on the CSI-RS-RNTI. For example, a first CSI-RS-RNTI may correspond to a first set of NBs or a first cell group, and a second CSI-RS-RNTI may correspond to a second set of NBs or a second cell group.

[0312] Fig. 27 Example content of a DCI format 2700 with a CRC scrambled by a CSI-RS-RNTI for triggering CSI-RS transmission in a subset of NBs in a set of NBs for one or more UEs according to an embodiment of the present disclosure is shown. Fig. 27 The illustrated embodiment of the contents of DCI format 2700 is for illustration only. Fig. 27 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0313] like Fig. 27As shown, the gNB configures a UE with a set of NBs, a CSI-RS-RNTI for scrambling the CRC of a DCI format, and a location in the DCI format for a CSI-RS triggering field that triggers CSI-RS transmission in a subset of NBs in the set of NBs 2710. For different UEs with the same configured CSI-RS-RNTI, the set of NBs may be configured separately for each UE. The gNB determines UEs from a group of one or more UEs that are configured with the same CSI-RS-RNTI and respective NB subsets for triggered CSI-RS transmission 2720. The gNB sets the value of the CSI-RS triggering field 2730 based on whether the gNB triggers CSI-RS transmission for the UE, and when CSI-RS transmission is triggered, based on the NB subset with triggered CSI-RS transmission.

[0314] The CSI-RS triggering field may include two bits, where a value of "00" does not trigger any CSI-RS transmission for the UE, and a value of "01", "10", or "11" triggers CSI-RS transmission in a first, second, and third NB subset, respectively, which may include all NBs in the NB set, or triggers CSI-RS transmission with a first, second, or third configuration in NBs indicated by a corresponding field in the DCI format. The gNB sends a DCI format with a CRC scrambled by the CSI-RS-RNTI 2740. The UE receives from the gNB the configuration of the NB set, the configuration of the CSI-RS-RNTI to scramble the CRC of the DCI format, and the configuration 2750 of the position of the CSI-RS triggering field in the DCI format that may trigger CSI-RS transmission in the NB subset.

[0315] The UE detects a DCI format with a CRC scrambled by a CSI-RS-RNTI 2760. The UE obtains a value of a CSI-RS triggering field 2770. When the value of the CSI-RS triggering field is "00", the UE does not receive CSI-RS, and when the value of the CSI-RS triggering field is "01", "10", or "11", the UE receives CSI-RS transmission in the first, second, and third NB subsets, respectively, or receives CSI-RS 2780 according to the first, second, or third configuration.

[0316] Fig.28 Example content of a DCI format 2800 with a CRC scrambled by a CSI-RS-RNTI is shown according to an embodiment of the present disclosure, wherein the format triggers CSI-RS transmission in a subset of NBs in a set of NBs for one or more UEs, and provides PUCCH resources and TPC commands for transmission of CSI reports. Fig.28 The illustrated embodiment of the contents of DCI format 2800 is for illustration only. Fig.28One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0317] like Fig.28 As shown, the gNB configures the UE with a set of NBs, a CSI-RS-RNTI for scrambling the CRC of the DCI format, and a location in the DCI format for a CSI-RS triggering field and a TPC command for adjusting the power of a PUCCH transmission including a CSI report 2810, wherein the CSI-RS triggering field triggers CSI-RS transmission in a subset of NBs in the set of NBs, and the TPC command is used to adjust the power of a PUCCH transmission including a CSI report. The set of NBs may be different for different UEs. The gNB determines UEs 2820 configured with the same CSI-RS-RNTI and respective subsets of NBs for triggering CSI-RS transmission from a group of one or more UEs.

[0318] Depending on whether the gNB triggers CSI-RS transmission for the UE, the gNB sets the value of the CSI-RS triggering field, and when CSI-RS transmission is triggered, according to the NB subset with triggered CSI-RS transmission, and even when the UE is not triggered to transmit CSI-RS transmission and does not send PUCCH conveying CSI reports, the UE can process the TPC command 2830 in the DCI format.

[0319] The CSI-RS trigger field may include two bits, where a value of "00" does not trigger any CSI-RS transmission for the UE, and a value of "01", "10", or "11" triggers CSI-RS transmission in a first, second, and third NB subset, respectively, which may include all NBs in the NB set. Additionally or alternatively, the CSI-RS trigger field may indicate a CSI-RS configuration. The TPC command may also include two bits having a value of "00", "01", "10", or "11" that maps, for example, to power adjustments of -3dB, -1dB, 1dB, and 3dB, respectively. The gNB sends a DCI format 2840 with a CRC scrambled by the CSI-RS-RNTI.

[0320] The UE receives from the gNB a configuration of a set of NBs, a configuration of a CSI-RS-RNTI to scramble a CRC of a DCI format, and a configuration of the location of a CSI-RS triggering field and a TPC field in the DCI format, where the CSI-RS triggering field can trigger CSI-RS transmission in a subset of NBs and the TPC field is used to adjust the power of the PUCCH conveying the CSI report 2850. The UE detects the DCI format with the CRC scrambled by the CSI-RS-RNTI 2860. The UE obtains values ​​for the CSI-RS triggering field and for the TPC command field 2870.

[0321] When the value of the CSI-RS triggering field is "00", the UE does not receive CSI-RS, and when the value of the CSI-RS triggering field is "01", "10" or "11", the UE receives CSI-RS transmission 2880 in the first, second and third NB subsets or according to the first, second or third CSI-RS configuration. The DCI format also includes an indication of the PUCCH resource n PUCCH The PUCCH resource field of the DCI format is used by the UE triggered by the first CSI-RS having a value different from "00" in the DCI format to send a PUCCH conveying a CSI report, and the UE having the nth CSI-RS having a value different from "00" in the DCI format CSI-RS +1CSI-RS triggered UE to use PUCCH resource n PUCCH +n CSI-RS The PUCCH 2890 conveying the CSI report is sent with a power adjusted based on the TPC command field value.

[0322] Fig.29 An example PUCCH resource determination 2900 is shown showing that a UE sends a PUCCH conveying a CSI report based on the PUCCH resources indicated in the DCI format triggering CSI-RS transmission according to an embodiment of the present disclosure. Fig.29 The illustrated embodiment of PUCCH resource determination 2900 is for illustration only. Fig.29 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0323] use Fig.29 For reference, a fourth UE, UE#3 2910 (having a CSI-RS triggering field and a reference PUCCH resource n for the UE in response to detecting a CRC having a CRC scrambled with a CSI-RS-RNTI and including a CSI-RS triggering field and a reference PUCCH resource n for the UE whose value is not "00" PUCCHBased on determining that the CSI-RS triggering field has a value other than "00" in a position before the position of the CSI-RS triggering field for UE#3 in the DCI format, UE#3 determines a PUCCH transmission conveying a CSI report in response to a measurement from a CSI-RS transmission associated with the CSI-RS triggering value for UE#3. PUCCH +2.

[0324] The gNB may configure the UE to report information about the configured N NB ≥M NB M in the NB set NB CSI of NBs, or M NB The value of can be defined in system operation. UE can NB Select M from the set of NBs NB For example, from the corresponding N NB N of NBs NB Among the measured CQI values, the UE can select M NB ≤N NB The maximum CQI value is indicated in the CSI report. NB A nice note.

[0325] The UE may also be configured by the gNB to include CSI reports for NBs that the UE is configured to receive PDCCH, or the inclusion of such CSI reports may be specified in system operation. It is also possible that the configured set of NBs does not include the NB that the UE is configured to receive PDCCH, and the UE may provide a separate CSI report for that NB. For example, the UE may provide CSI reports for NBs that the UE is configured to receive PDCCH with greater periodicity than other NBs.

[0326] When UE reports about M NB When the CSI of >1 NB, the UE can report the maximum CQI value CQI max (j 0 ) and the corresponding NB index j 0 , and report the differential CQI offset value DCQI(j) (0≤j≤M NB -1 and j≠j 0 ), where DCQI(j) = CQI max (j 0)-CQI(j). For example, for a DCQI(j) value represented by 2 bits, the mapping from the 2-bit differential CQI value to the offset value may be as shown in Table 2. NB NBs and M with CSI reporting NB NB, M NB The index of each NB can be obtained using, for example, a combined index in the LTE specification.

[0327] Used to represent M NB The number of bits for the position of each NB is The index of the NB may be arranged first in the CSI report, followed by the corresponding CSI value or NB index pair, and the CSI report may be arranged, for example, starting from the NB with the largest CQI value and continuing with other NBs in ascending index order.

[0328] Table 2. Mapping of differential CQI values ​​to offset values

[0329]

[0330]

[0331] The NB that the UE is configured to receive the PDCCH may hop between time slots within the configured NB set. For example, the NB that the UE is configured to receive the PDCCH may cycle through the NBs in the configured NB set between time slots according to the ascending order of the NB index, or may have a hopping pattern that maximizes frequency diversity, such as the SRS transmission BW hopping pattern described in the LTE specification.

[0332] The UE can then receive the PDCCH and CSI-RS transmissions in the same NB while reducing the impact of the delay associated with retuning from a first NB where the UE is configured to receive the PDCCH to a second NB to receive the CSI-RS transmission and then back to the first NB to receive the PDCCH. This is particularly useful when the retuning time between different NBs is relatively large and the UE cannot receive CSI-RS transmissions for all corresponding NBs in a single time slot.

[0333] When the UE is not configured to receive PDSCH or other DL signaling in a timeslot, the UE may determine potential scheduling of the PDSCH for the remaining duration in the timeslot after the UE decodes a symbol of the PDSCH and one or more additional symbols associated with a processing delay for retuning to a different NB to receive the PDSCH and possibly receive the CSI-RS.

[0334] When a UE is configured to receive PDSCH or other DL signaling in a timeslot according to a NB hopping pattern, and the UE does not have sufficient time to re-tune to the next NB, then before the start of the next timeslot, as discussed subsequently, the UE may skip re-tuning to the next NB and re-establish the NB hopping pattern in a later timeslot, or the UE may re-tune to the next NB but miss reception of the PDCCH due to the re-tuning. To mitigate the impact of not being able to receive the PDCCH in a timeslot, the gNB may schedule a multi-slot transmission of the PDCCH to the UE, where the PDSCH is transmitted in different NBs in different timeslots according to the NB hopping pattern. The UE may then receive the PDSCH after re-tuning to the different NBs in different timeslots, when the UE may re-tune within a time period no greater than the configured duration of the transmission of the PDCCH in the timeslot.

[0335] Fig.30 A frequency hopping pattern 3000 of a NB in ​​which a UE is configured to receive a PDCCH according to an embodiment of the present disclosure is shown. Fig.30 The illustrated embodiment of frequency hopping pattern 3000 is for illustration only. Fig.30 One or more of the components shown may be implemented in dedicated circuits configured to perform the functions described, or one or more components may be implemented by one or more processors executing instructions to perform the functions described.Other embodiments may be used without departing from the scope of the present disclosure.

[0336] like Fig.30 As shown, the UE is configured with a NB set including four NBs (NB0, NB1, NB2, and NB3), and resources in the first symbol of the NB are used to receive PDCCH 3005. In the first time slot, the UE receives PDCCH 3010 in NB1, and may also receive CSI-RS transmission in a time slot symbol having a first time distance from the end of the first time slot that is greater than the UE re-tuning period. The UE is not configured to receive any DL signaling during a time period equal to the re-tuning period relative to the end of the first time slot.

[0337] During the first time distance, the UE may re-tune to NB3 for receiving PDCCH in the second time slot. In the second time slot, the UE receives PDCCH 3020 in NB3 and may also receive CSI-RS transmissions in time slot symbols having a second time distance from the end of the second time slot greater than the UE re-tune period. The UE is not configured to receive other DL signaling during a time period equal to the re-tune period relative to the end of the second time slot. During the second time distance, the UE may re-tune to NB0 for receiving PDCCH in the third time slot. In the third time slot, the UE receives PDCCH 3030 in NB0 and may also receive CSI-RS transmissions in time slot symbols having a third time distance from the end of the third time slot greater than the UE re-tune period.

[0338] The UE is not configured to receive any DL signaling during a time period equal to the retuning period relative to the end of the third time slot. During the third time distance, the UE may retuned to NB2 for receiving the PDCCH in the fourth time slot. In the fourth time slot, the UE receives PDCCH 3040 in NB2 and may also receive CSI-RS transmissions in time slot symbols having a fourth time distance from the end of the fourth time slot greater than the UE retuning period.

[0339] The UE is not configured to receive any DL signaling during a time period equal to the re-tuning period relative to the end of the fourth time slot. During the fourth time distance, the UE may re-tune to NB1 for receiving the PDCCH in the fifth time slot. In the fifth time slot, the UE receives PDCCH 3050 in NB1 and may also receive CSI-RS transmissions in the time slot symbols, and is configured to receive DL signaling (such as PDCCH) at a fifth time distance from the end of the fifth time slot that is no greater than the UE re-tune period. While receiving DL signaling in the fifth time slot, the UE does not have sufficient time to re-tune to NB3 for receiving the PDCCH in the sixth time slot. There are two methods for UE behavior.

[0340] The first method is that the UE re-tunes to NB3 in the sixth time slot for reception of possible CSI-RS transmission, but the UE is unable to receive PDCCH 3060. The second method is that the UE remains tuned to NB1 in the sixth time slot to receive PDCCH 3065 in the sixth time slot. The first method avoids error conditions that may occur, for example, when the UE fails to detect a DL DCI format in the fifth time slot that schedules DL data channel reception in the fifth time slot and tunes to NB3 in the sixth time slot.

[0341] The second method relies on the gNB to account for potential error conditions. Both methods enable continuous scheduling for the UE; the first method is by applying multi-slot scheduling and relying on the UE to re-tune during the time period in the slot used for DL ​​control channel transmission, and the second method is by applying single-slot or multi-slot scheduling for the UE. The UE resumes the NB frequency hopping pattern in the seventh slot 3070. The UE behavior can be specified in the system operation or configured by the gNB to the UE according to one of the two methods.

[0342] SRS transmissions on multiple NBs may follow similar principles to CSI-RS transmissions on multiple NBs, and the following description is summarized for completeness. SRS transmissions in NBs may be precoded or non-precoded. In the former case, the precoding may also be configured to the UE and may be the same for all NBs (single configuration) or different for different NBs (separate configurations). SRS transmissions may include zero power SRS and non-zero power SRS.

[0343] In order for the UE to transmit SRS in a NB in ​​the NB set, the UE needs to re-tune the RF transmitter component of the UE to each NB in ​​the NB set. When the UE is configured to transmit UL signaling in a NB, such as a random access channel, or PUSCH, or PUCCH (such as a PUCCH conveying HARQ-ACK), and the UE is also configured to transmit SRS in a different NB, and the RF re-tuning delay makes it impossible for the UE to transmit UL signaling and SRS, the UE may abandon SRS transmission.

[0344] For a TDD system and a UE with a single duplexer, the UE may transmit an SRS in the second NB after receiving the PDCCH in the first NB when the retuning delay is less than the time interval between the last slot symbol for transmitting the PDCCH in the first NB and the first slot symbol for transmitting the SRS in the second NB that the UE is configured to receive. The UE may re-tune to the first NB to receive the PDCCH after transmitting the SRS in the second NB when the retuning delay is less than the time interval between the last slot symbol for transmitting the SRS in the second NB and the first slot symbol for transmitting the PDCCH in the first NB.

[0345] When the UE detects in the PDCCH that the UE is scheduled to receive PDSCH or a DCI format of PDSCH in a NB, and the UE is also configured to send SRS in a different NB, the UE may abandon the transmission of SRS. For TDD systems and UEs with a single duplexer, the UE may abandon SRS transmission when the retuning delay is greater than the time between the last symbol of PDSCH reception or PUSCH transmission and the first symbol of SRS transmission (or vice versa).

[0346] In one example, SRS transmission in a set of one or more NBs may be semi-continuous or periodic. The UE is configured by a higher layer with the set of NBs and the parameters for SRS transmission in each NB in ​​the set of NBs. The SRS transmission parameters may be the same for all NBs, but may exclude the position of the time slot symbols used for SRS transmission, as discussed further below, and may be configured jointly for all NBs, or some parameters may be different for each NB and configured separately for each NB. The SRS transmission parameters may include one or more of the number of combs, the number of time slot symbols used for SRS transmission in each NB (duration), the transmission comb, the starting PRB, periodicity, BW, cyclic shift, precoding, or the number of antenna ports.

[0347] In another example, SRS transmissions in NBs of the NB set may be aperiodic and triggered by a DCI format conveyed by PDCCH. The DCI format may be a DL DCI format that schedules PDSCH transmissions to UEs, or may be a separate DCI format with content that triggers SRS transmissions from one or more UEs.

[0348] When the DCI format that triggers SRS transmission in one or more NBs in the NB set is a UL DCI format or a DL DCI format, the DCI format may include a field indicating the NB in ​​the NB set used for SRS transmission from the UE, or may include a field indicating the SRS transmission configuration, in a manner similar to that described with respect to the triggering of CSI-RS transmission. For the UL DCI format that schedules the transmission of PUSCH from the UE and triggers SRS transmission from the UE in NBs in the NB set, when the NB of the PUSCH transmission is also the NB with the triggered SRS transmission, in order to be able to send the PUSCH, the UE may expect the first SRS transmission to occur in the NB of the PUSCH transmission, and subsequent SRS transmissions in the remaining NBs according to the ascending (or descending) order of the NB index.

[0349] When the NB of the PUSCH transmission is not the NB with the triggered SRS transmission, the UE may send the PUSCH in one or more time slots, and then, after one or more time slots, re-tune to the NB with the triggered SRS transmission. It is also possible that the SRS transmissions in the NBs are based on the ascending NB index, including the NB of the PUSCH transmission when the SRS transmission is triggered.

[0350] A field in the UL DCI format that triggers SRS transmission in one or more NBs in the NB set configured by the UE may include an indication of the NB. For example, a field with two bits may use a value of "00" to indicate no SRS transmission, and use values ​​of "01", "10" and "11" to indicate SRS transmission in a first, second or third configured subset of NBs in the NB set, or indicate a first, second or third configuration for SRS transmission. The parameters of the SRS transmission in each NB may be the same or different.

[0351] The position of the timeslot symbols used for SRS transmission in each NB may be the same or different. For example, when the SRS transmissions in different NBs are in different timeslots, the respective timeslot symbols may be the same. For example, when the SRS transmissions in at least some NBs are in the same timeslot, the respective timeslot symbols are different, and the corresponding offset of the number of symbols used for consecutive SRS transmissions may be determined from the retuning delay of the UE with the associated triggered SRS transmission, or may be signaled by the gNB through UE-common higher layer signaling such as system information or through UE-specific higher layer signaling.

[0352] SRS transmissions in the gNB may also be performed over multiple slot symbols, where, for example, the SRS transmissions are from different antenna ports in different symbols (such as from a first antenna port in a first symbol and from a second antenna port in a second symbol), or from the same antenna port, to enable the gNB to obtain a more accurate estimate of the channel medium from the SRS transmissions.

[0353] When the DCI format triggering the SRS transmission in the NB in ​​the NB set for the UE is not a UL DCI format or a DL DCI format, the DCI format may have the same size as the UL DCI format or the DL DCI format decoded by the UE, or may have the same size as the size of the DCI format decoded by the UE for other purposes (such as for obtaining TPC commands). The CRC of the DCI format may be scrambled with an RNTI (such as an SRS-RNTI) specific to the triggering of the SRS transmission. The DCI format with the SRS-RNTI is referred to as DCI format X for brevity.

[0354] Using DCI format X, for each UE in a group of UEs configured with the same SRS-RNTI, the gNB may trigger SRS transmission in a different NB in ​​the configured set of NBs and possibly in a different cell. The UE may be configured via the index parameter Index-SRS the position in DCI format X where it may obtain the SRS triggering field indicating SRS transmission in a subset of NBs in the configured set of NBs or indicating an SRS transmission configuration. The SRS triggering field may operate as described for the UL DCI format or DL ​​DCI format, or may have an increased granularity similar to the CSI-RS triggering.

[0355] It is also possible that when the SRS trigger field triggers SRS transmission, it does so for all NBs in the NB set. The SRS trigger field may then include a single bit for each UE in each cell, where a value of "0" indicates no SRS triggering, and a value of "1" indicates SRS triggering in all NBs in the NB set. The DL DCI format or DCI format X may also include a TPC field for the UE to adjust the SRS transmission power. The TPC command field may be adjacent to the SRS transmission trigger field (before or after), or may be located in a different configured position for each UE. The UE may be configured with more than one SRS-RNTI, where the content of DCI format X is interpreted based on the SRS-RNTI. For example, a first SRS-RNTI may correspond to a first NB set or a first cell group, and a second SRS-RNTI may correspond to a second NB set or a second cell group.

[0356] The functionality of DCI format T and DCI format X may be combined using DCI format Y, which may have the same size as a UL DCI format or DL ​​DCI format decoded by the UE, or the same size as a DCI format decoded by the UE for other purposes (such as for obtaining a TPC command). The UE may be configured with an RS-RNTI for triggering both CSI-RS transmission and SRS transmission, and with one or more corresponding positions for a CSI-RS trigger field for corresponding one or more cells, followed by an SRS trigger field, and followed by a TPC command field (or in any other order for these three fields), wherein the cell for CSI-RS reception may be different from the cell for SRS transmission, and the link between the cell index and the trigger position is configured separately. In response to a CSI-RS trigger value other than "00", such as Fig.29 As shown, DCI format Y may also include reference PUCCH resources for PUCCH transmission.

[0357] Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

[0358] Nothing in this application should be read as implying that any particular element, step, or function is an essential element that must be included in the scope of the claims. The scope of the patented subject matter is limited only by the claims. In addition, no claim is intended to invoke 35 U.S.C. § 112(f) unless the exact words "means for" are followed by a participle.

Claims

1. A method performed by a user equipment (UE) in a communication system, the method comprising: receiving information about a common search space from a base station; receiving information about a UE-specific search space from a base station; determining a first number of physical downlink control channel (PDCCH) candidates for a common search space in a time slot based on the information about the common search space; determining a second number of PDCCH candidates for a UE-specific search space in a time slot based on the information about the UE-specific search space and the first number of PDCCH candidates for a common search space in a time slot; and Monitor the PDCCH candidates of the common search space in the time slot and the PDCCH candidates of the UE-specific search space in the time slot, The information about the public search space includes periodic information of the public search space, and The information about the UE-specific search space includes periodicity information of the UE-specific search space.

2. The method according to claim 1, wherein: The second number of PDCCH candidates of the UE-specific search space in the slot is reduced with the first number of PDCCH candidates of the common search space in the slot.

3. The method according to claim 1, wherein: A control channel element (CCE) to resource element group (REG) mapping type of a control resource set and a REG bundle size associated with the interleaved CCE to REG mapping of the control resource set are received from a base station.

4. A method performed by a base station in a communication system, the method comprising: sending information about a common search space to a user equipment (UE); Sending information about a UE-specific search space to a user equipment (UE); determining a first number of physical downlink control channel (PDCCH) candidates for a common search space in a time slot based on the information about the common search space; determining a second number of PDCCH candidates for a UE-specific search space in a time slot based on the information about the UE-specific search space and the first number of PDCCH candidates for a common search space in a time slot; as well as Send control information to the UE based on the PDCCH candidates of the common search space in the time slot and the PDCCH candidates of the UE-specific search space in the time slot, The information about the public search space includes periodic information of the public search space, and The information about the UE-specific search space includes periodicity information of the UE-specific search space.

5. The method according to claim 4, wherein: The second number of PDCCH candidates of the UE-specific search space in the slot is reduced with the first number of PDCCH candidates of the common search space in the slot.

6. The method according to claim 4, wherein: The control channel element (CCE) to resource element group (REG) mapping type of a control resource set and the REG bundle size associated with the interleaved CCE to REG mapping of the control resource set are signaled by the base station.

7. A user equipment (UE) in a communication system, the UE comprising: Transceiver; as well as A controller is coupled to the transceiver and is configured to: receiving information about a common search space from a base station, receiving information about a UE-specific search space from a base station, determining a first number of physical downlink control channel (PDCCH) candidates for a common search space in a time slot based on the information about the common search space, determining a second number of PDCCH candidates for a UE-specific search space in a time slot based on the information about the UE-specific search space and the first number of PDCCH candidates for a common search space in a time slot, and Monitor the PDCCH candidates of the common search space in the time slot and the PDCCH candidates of the UE-specific search space in the time slot, The information about the public search space includes periodic information of the public search space, and The information about the UE-specific search space includes periodicity information of the UE-specific search space.

8. The UE according to claim 7, wherein: The second number of PDCCH candidates of the UE-specific search space in the slot is reduced with the first number of PDCCH candidates of the common search space in the slot.

9. The UE according to claim 7, wherein: A control channel element (CCE) to resource element group (REG) mapping type of a control resource set and a REG bundle size associated with the interleaved CCE to REG mapping of the control resource set are received from a base station.

10. A base station in a communication system, the base station comprising: Transceiver; as well as A controller is coupled to the transceiver and is configured to: Sending information about a common search space to a user equipment (UE), Sending information about UE-specific search spaces to a user equipment (UE), determining a first number of physical downlink control channel (PDCCH) candidates for a common search space in a time slot based on information about the common search space, determining a second number of PDCCH candidates for a UE-specific search space in a time slot based on the information about the UE-specific search space and the first number of PDCCH candidates for a common search space in a time slot, and Send control information to the UE based on the PDCCH candidates of the common search space in the time slot and the PDCCH candidates of the UE-specific search space in the time slot, The information about the public search space includes periodic information of the public search space, and The information about the UE-specific search space includes periodicity information of the UE-specific search space.

11. The base station according to claim 10, wherein: The second number of PDCCH candidates of the UE-specific search space in the slot is reduced with the first number of PDCCH candidates of the common search space in the slot.

12. The base station according to claim 10, wherein: The control channel element (CCE) to resource element group (REG) mapping type of a control resource set and the REG bundle size associated with the interleaved CCE to REG mapping of the control resource set are signaled by the base station.

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