Transmission structure and format for DL ​​control channel

Abstract

A method for a user equipment (UE) to receive a physical downlink control channel (PDCCH) is provided. The UE receives configuration information for a first control resource set, the configuration information including the number of symbols in the time domain and the number of resource blocks (RBs) in the frequency domain, and determines the number N of first frequency-consecutive RBs. bundle Receives setting information indicating N bundle,1 The UE receives a PDCCH in a first control resource set in a frequency distribution block of a RB. bundle,1 It is assumed that the RBs have the same precoding. A method for configuring a search space to reduce the number of channel estimates that a UE performs to decode a PDCCH compared to a conventional search space is further provided.

Description

[Technical Field]

[0001] The present disclosure 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 technology]

[0002] 5G mobile communications, which is expected to be first commercialized around 2020, has recently been gaining momentum with all the technological activity around the world regarding various candidate technologies in industry and academia. Available candidate technologies for 5G mobile communications include massive antenna technologies to provide beamforming gains and support increased capacity across frequencies from existing cellular frequency bands to higher frequencies, new waveforms (e.g., new radio access technologies (RATs)) to flexibly accommodate diverse services / applications with different requirements, and new multiple access schemes to support massive connectivity. The International Telecommunication Union (ITU) classifies post-2020 international mobile telecommunications (IMT) usage scenarios into three main groups: enhanced mobile broadband, machine-type communications (MTC), and ultra-reliable and low latency communications. Furthermore, the ITC defines maximum data rates of 20 gigabits per second (Gb / s), user-experienced data rates of 100 megabits per second (Mb / s), and spectrum efficiency. Three times better efficiency, 500 kilometers per hour (km / h) mobility, 1ms latency, 106 devices / km 2 connection density, 100x network energy efficiency and 10Mb / s / m 2 Specify target requirements such as up to area traffic capacity to be supported. Summary of the Invention [Problem to be solved by the invention]

[0003] While it is not necessary to meet all requirements simultaneously, 5G network designs can provide the flexibility to support a variety of applications that meet some of the above requirements on a use case basis. [Means for solving the problem]

[0004] In one embodiment, a method for receiving a physical downlink control channel (PDCCH) in a user equipment (UE) is provided, the method including receiving configuration information for a first control resource set including a number of symbols in the time domain and a number of resource blocks (RBs) in the frequency domain. The method further includes receiving a first frequency-consecutive RB number N bundle,1 The method further includes receiving configuration information indicative of N bundle,1 The UE receives a first PDCCH on a control resource set within a frequency distribution block of a RB. bundle,1 It is assumed that the RBs have the same precoding.

[0005] In another embodiment, a user equipment (UE) includes a receiver configured to receive configuration information for a first control resource set, the configuration information including a number of symbols in the time domain and a number of resource blocks (RBs) in the frequency domain, the receiver further including a number N of first frequency-consecutive RBs. bundle The receiver is further configured to receive configuration information indicating N bundle,1 The receiver is configured to receive a physical downlink control channel (PDCCH) on a control resource set within a frequency distribution block of RBs. ... bundle,1 It is assumed that the RBs have the same precoding.

[0006] In yet another embodiment, the base station includes a transmitter configured to transmit configuration information for a first control resource set, the configuration information including the number of symbols in the time domain and the number of resource blocks (RBs) in the frequency domain. The transmitter further transmits the number N of first frequency-consecutive RBs. bundle The transmitter is further configured to transmit setting information indicating N bundle The PDCCH is configured to transmit a physical downlink control channel (PDCCH) in a control resource set within a frequency distribution block of RB. A demodulation reference signal for transmitting the PDCCH is bundle,1 The RBs have the same precoding.

[0007] Other technical features may become readily apparent to those skilled in the art from the following drawings, descriptions and claims.

[0008] Before proceeding to the detailed description below, it may be advantageous to define certain words and phrases used throughout this patent document. The term "couple" and its derivatives indicate some indirect or direct communication between two or more elements, whether or not those elements are in physical contact with one another. The terms "transmit," "receive," and "communicate" and their derivatives include both direct and indirect communication. The terms "include" and "comprise" and their derivatives mean including without limitation. The term "or" is used as an inclusive term to mean and / or. The phrase "associated with" and its derivatives means include, included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave with, juxtapose with, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, and the like. The term "controller" means a device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with a particular controller may be processed in a centralized manner, either locally or remotely, or in a distributed manner. The phrase "at least one of," when used in conjunction with a list of items, means that different combinations of one or more of the listed items may be used.For example, "at least one of A, B, and C" includes any one of the following combinations: A, B, C, A and B, A and C, B and C, and A, B, and C.

[0009] Furthermore, various functions described below may be implemented or supported by one or more computer programs, each formed of one or more 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, command sets, procedures, functions, objects, classes, instances, associated data, or portions thereof, configured for implementation in suitable computer-readable program code. The term "computer-readable program code" includes types of computer code, including source code, object code, and executable code. The term "computer-readable medium" includes any type of medium that can be accessed by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, compact disc (CD), digital video disc (DVD), or any other type of memory. "Non-transitory" computer-readable medium excludes communications links that convey wired, wireless, optical, transient, electrical, or other signals. Non-transitory computer-readable media include media on which data can be permanently stored, and media on which data can be stored and later overwritten, such as re-recordable optical disks or erasable memory devices.

[0010] Definitions for other specific words and phrases are provided throughout this patent specification. Those skilled in the art should understand that in many, if not most, instances such definitions may apply not only to prior art but also to future uses of such defined words and phrases. [Effects of the Invention]

[0011] The present invention relates to a pre-5G or 5G communication system that is provided to support higher data rates than fourth generation (4G) communication systems such as Long Term Evolution (LTE). Embodiments of the present invention provide a transmission structure and format in the advanced communication system.

[0012] 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, in which like reference numerals designate like parts throughout. [Brief explanation of the drawings]

[0013] [Figure 1] 1 illustrates an exemplary wireless network in accordance with an embodiment of the present invention. [Figure 2] 1 illustrates an exemplary eNB according to an embodiment of the present invention. [Figure 3] 1 illustrates an exemplary UE according to an embodiment of the present invention. [Figure 4] 1 is a diagram illustrating an exemplary DL slot structure for PDSCH or PDCCH transmission according to an embodiment of the present invention. [Figure 5] 1 is a diagram illustrating an exemplary UL slot structure for PUSCH or PUCCH transmission according to an embodiment of the present invention. [Figure 6] 1 is a diagram illustrating an exemplary hybrid slot structure for DL ​​and UL transmissions according to an embodiment of the present invention. [Figure 7] 1 is a diagram illustrating an exemplary transmitter structure using OFDM according to an embodiment of the present invention. [Figure 8] 1 is a diagram illustrating an exemplary receiver structure using OFDM according to an embodiment of the present invention. [Figure 9] 1 is a diagram illustrating an exemplary encoding process for a DCI format according to an embodiment of the present invention. [Figure 10] 1 is a diagram illustrating an example decoding process for a DCI format for use with a UE according to an embodiment of the present invention. [Figure 11] 10 is a diagram illustrating an exemplary distributed PDCCH transmission structure according to each CCE aggregation level according to an embodiment of the present invention. [Figure 12] 10 is a diagram illustrating an exemplary localization PDCCH transmission structure according to each CCE aggregation level according to an embodiment of the present invention. [Figure 13] 1 is a diagram illustrating exemplary PDCCH and PDSCH transmissions using the same DMRS for demodulation according to an embodiment of the present invention. [Figure 14] 10 is a diagram illustrating an example operation in which a UE assumes the same DMRS precoding in a given slot and predetermined RBs of a DL control resource set according to an embodiment of the present invention. [Figure 15] 10 is a diagram illustrating an exemplary operation of a DCI format including a binary flag for indicating one of multiple transmission schemes for PDSCH transmission or PUSCH transmission according to an embodiment of the present invention. [Figure 16] 1 is a diagram illustrating an exemplary nested structure of PDCCH candidates according to an embodiment of the present invention. [Figure 17] 10 is a diagram illustrating an example process for determining CCEs for PDCCH candidates based on a first implementation example for a nested PDCCH search space structure according to an embodiment of the present invention. [Figure 18] 10 is a diagram illustrating an exemplary determination of CCEs for PDCCH candidates based on a first approach of a first embodiment for a nested PDCCH search space structure according to an embodiment of the present invention. [Figure 19] 10 is a diagram illustrating an exemplary determination of CCEs for PDCCH candidates based on a second embodiment according to an embodiment of the present invention. [Figure 20] 10 is a diagram illustrating exemplary CCE indexes of PDCCH candidates according to a second embodiment of the present invention. [Figure 21] 1 is a diagram illustrating an example control resource subset within a control resource set according to an embodiment of the present invention. [Figure 22]10 is a diagram illustrating exemplary CCE indexes of PDCCH candidates overlapping one or two OFDM symbols in a nested structure according to an embodiment of the present invention. [Figure 23] 10 is a diagram illustrating nested allocation of CCE indices among PDCCH candidates based on an ascending order of PDCCH candidates according to an embodiment of the present invention. [Figure 24] 10 is a diagram illustrating nested allocation of CCE indices among PDCCH candidates based on CCE index restrictions for multiple PDCCH candidates according to an embodiment of the present invention. [Figure 25] 10 is a diagram illustrating an example of CSI-RS transmission at multiple NBs where a UE retunes to an NB after receiving a CSI-RS transmission that the UE is configured for PDCCH reception, according to an embodiment of the present invention. [Figure 26] 10 is a diagram illustrating exemplary CSI-RS transmissions at multiple NBs, with a UE retuning at each NB configured to receive CSI-RS transmissions before retuning to an NB configured for PDCCH reception according to an embodiment of the present invention. [Figure 27] 10 is a diagram illustrating exemplary content of a DCI format in which the CRC is scrambled by a CSI-RS-RNTI that triggers CSI-RS transmission at a subset of NBs from a set of NBs for the UE according to an embodiment of the present invention. [Figure 28] 10 is a diagram illustrating exemplary content of a DCI format having a CRC scrambled by a CSI-RS-RNTI that triggers CSI-RS transmission at a subset of NBs from a set of NBs for one or more UEs and provides PUCCH resources and TPC commands for transmission of a CSI report according to an embodiment of the present invention. [Figure 29] 10 is a diagram illustrating an example PUCCH resource determination for a UE to transmit a PUCCH carrying a CSI report based on a PUCCH resource indicated in a DCI format that triggers CSI-RS transmission according to an embodiment of the present invention. [Figure 30]1 is a diagram illustrating a hopping pattern of an NB configured so that a UE receives a PDCCH according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] 1 through 30 described below, and various embodiments used to explain the principles of the present disclosure in this patent specification, are by way of example only and should not be construed as limiting the scope of the present disclosure in any manner. Those skilled in the art will understand that the principles of the present disclosure may be embodied in any suitably configured wireless communication system or device.

[0015] The following documents and standard descriptions are incorporated by reference into this 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."

[0016] 1 to 4b below illustrate various embodiments implemented in a wireless communication system using orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication technology. The descriptions in FIGS. 1 to 3 do not imply physical or structural limitations on how different embodiments may be implemented. Different embodiments of the present disclosure may be implemented in any appropriately configured communication system.

[0017] 1 is a diagram illustrating an exemplary wireless network according to an embodiment of the present disclosure. The wireless network embodiment shown in FIG. 1 is for illustrative purposes only. Other embodiments for wireless network 100 may be used within the scope of the present disclosure.

[0018] 1, wireless network 100 includes eNB 101, eNB 102, and eNB 103. eNB 101 communicates with eNB 102 and eNB 103. In addition, eNB 101 communicates with at least one network 130, such as the Internet, a dedicated Internet Protocol (IP) network, or other data network.

[0019] eNB 102 provides wireless broadband access to network 130 for a first plurality of user equipment (UE) within eNB 102's coverage area 120. The first plurality of UEs includes UE 111, which may be located at a small or medium-sized business (SB); UE 112, which may be located at a large enterprise (E); UE 113, which may be located at a Wi-Fi hotspot (HS); UE 114, which may be located at a first residential area (R); UE 115, which may be located at a second residential area (R); and UE 116, which may be a mobile device (M) such as a mobile phone, wireless laptop, wireless PDA, etc. eNB 103 provides wireless broadband access to network 130 for a second plurality of UEs within eNB 103's coverage area 125. 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.

[0020] Depending on the network type, the terms "base station" or "BS" can refer to a component (or collection of components) configured to provide wireless access to a network, such as a transmission point (TP), a transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G base station (gNB), a macrocell, a femtocell, a Wi-Fi access point (AP), or other wireless-enabled device. A base station can provide wireless access via one or more wireless communication protocols, such as 5G 3GPP New Radio Interface / Access (NR), long term evolution (LTE), LTE-advanced (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 specification to refer to the network infrastructure that provides wireless access to remote terminals. Furthermore, depending on the network type, the term "user equipment" or "UE" can refer to any component such as a "mobile station," "subscriber station," "remote terminal," "wireless terminal," "terminal," "receiving point," or "user device." For convenience, the terms "user equipment" and "UE" are used in this patent specification to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (e.g., a mobile phone or smartphone) or a commonly considered fixed device (e.g., a desktop computer or vending machine).

[0021] The dotted lines indicate the approximate extent of the coverage areas (120 and 125), which are shown as approximately circular for purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with eNBs, e.g., 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 due to natural and man-made obstacles.

[0022] As described in detail below, one or more of the UEs (111-116) include circuitry, programming, or a combination thereof for efficient CSI reporting for a PUCCH in an advanced wireless communication system. In certain embodiments, one or more of the eNBs (101-103) include circuitry, programming, or a combination thereof for receiving efficient CSI reporting for a PUCCH in an advanced wireless communication system.

[0023] While Figure 1 illustrates one embodiment of a wireless network, various variations can be made to Figure 1. For example, a wireless network can include any number of eNBs and any number of UEs in any suitable arrangement. Furthermore, eNB 101 can directly communicate with any number of UEs and provide the UEs with wireless broadband access to network 130. Similarly, each eNB (102-103) can directly communicate with network 130 and provide the UEs with direct wireless broadband access to network 130. Additionally, eNBs 101, 102, and / or 103 can provide access to other or additional external networks, such as an external telephone network or other type of data network.

[0024] 2 is a diagram illustrating an exemplary eNB 102 according to an embodiment of the present invention. The embodiment of the eNB 102 illustrated in FIG. 2 is for illustrative purposes only, and the eNBs (101 and 103) of FIG. 1 may have the same or similar configuration. However, eNBs may have a variety of different configurations, and FIG. 2 does not limit the scope of the present invention to any particular implementation of an eNB.

[0025] 2, the eNB 102 includes multiple antennas (205a-205n), multiple RF transceivers (210a-210n), transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. Additionally, the eNB 102 includes a controller / processor 225, memory 230, and a backhaul or network interface 235.

[0026] The RF transceivers 210a-210n receive incoming RF signals from the antennas 205a-205n, such as signals transmitted by UEs within the network 100. The RF transceivers 210a-210n down-convert the 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.

[0027] The TX processing circuitry 215 receives analog or digital data (e.g., voice data, web data, email, or interactive video game data) from the controller / processor 225. The TX processing circuitry 215 encodes, multiplexes, and / or digitizes the outgoing baseband data and generates a processed baseband or IF signal. The RF transceivers (210a-210n) receive the outgoing processed baseband or IF signal from the TX processing circuitry 215 and upconvert the baseband or IF signal to an RF signal that is transmitted via the antennas (205a-205n).

[0028] 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 via the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 according to well-known principles. The controller / processor 225 may also support additional functionality, such as more advanced wireless communication functions. For example, the controller / processor 225 may support beamforming or directional routing operations, in which outgoing signals from multiple antennas 205a-205n are differentially weighted to effectively steer in a desired direction. Any of a variety of other functions may be supported in the eNB 102 by the controller / processor 225.

[0029] Controller / processor 225 can also execute programs and other processes, such as the operating system, that reside in memory 230. Controller / processor 225 can move data in and out of memory 230 as required by the executing processes.

[0030] The controller / processor 225 is also coupled to a backhaul or network interface 235. The backhaul or network interface 235 enables the eNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 235 may support communication over any suitable wired or wireless connection. For example, if the eNB 102 is embodied as part of a cellular communication system (e.g., supporting 5G, LTE, or LTE-A), the interface 235 may enable the eNB 102 to communicate with other eNBs over a wired or wireless backhaul connection. If the eNB 102 is embodied as an access point, the interface 235 may enable the eNB 102 to transmit over a wired or wireless local area network or over a larger network (e.g., the Internet) over a wired or wireless connection. The interface 235 includes any suitable structure supporting communication over a wired or wireless link, e.g., an Ethernet or RF transceiver.

[0031] The memory 230 is coupled to the controller / processor 225. A portion of the memory 230 may include RAM, and another portion of the memory 230 may include flash memory or other ROM.

[0032] While FIG. 2 illustrates one example of an eNB 102, various variations can be made to FIG. 2. For example, the eNB 102 can include any number of each component shown in FIG. 2. As one particular example, an access point can include multiple interfaces 235, and the controller / processor 225 can support a routing function for routing data between different network addresses. As another particular example, although illustrated as including a single instance of TX processing circuitry 215 and a single instance of RX processing circuitry 220, the eNB 102 can include multiple instances of each (e.g., one per RF transceiver). Furthermore, various components of FIG. 2 can be combined, subdivided, or omitted, and additional components can be added as needed.

[0033] 3 is a diagram illustrating an exemplary UE 116 according to an embodiment of the present invention. The embodiment of the UE 116 illustrated in FIG. 3 is for illustrative purposes only, and the UEs (111-115) in FIG. 1 may have the same or similar configurations. However, UEs may have a variety of different configurations, and FIG. 3 does not limit the scope of the present disclosure to any particular implementation of a UE.

[0034] 3, the UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, a TX processing circuit 315, a microphone 320, and a receive (RX) processing circuit 325. Additionally, the UE 116 includes a speaker 330, a processor 340, an input / output (I / O) interface (IF) 345, a touchscreen 350, a display 355, and a memory 360. The memory 360 includes an OS 361 and one or more applications 362.

[0035] The RF transceiver 310 receives from the antenna 305 an inbound RF signal transmitted by an eNB of the network 100. The RF transceiver 310 down-converts the inbound RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is transmitted to the RX processing circuitry 325, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuitry 325 transmits the processed baseband signal to the speaker 330 (e.g., voice data) or to the processor 340 for further processing (e.g., web browsing data).

[0036] TX processing circuitry 315 receives analog or digital voice data from microphone 320 or other outbound baseband data (e.g., web data, email, or interactive video game data) from processor 340. TX processing circuitry 315 encodes, multiplexes, and / or digitizes the outbound baseband data and generates a processed baseband or IF signal. RF transceiver 310 receives the outbound processed baseband or IF signal from TX processing circuitry 315 and upconverts the baseband or IF signal into an RF signal that is transmitted via antenna 305.

[0037] Processor 340 may include one or more processors or other processing devices and may control the overall operation of UE 116 by executing OS 361 stored in memory 360. For example, processor 340 may control the reception of forward channel signals and the transmission of reverse channel signals by RF transceiver 310, RX processing circuitry 325, and TX processing circuitry 315 according to well-known principles. In some embodiments, processor 340 includes at least one microprocessor or microcontroller.

[0038] Processor 340 may also execute other processes and programs resident in memory 360, such as processes for beam management. Processor 340 may move data in and out of memory 360 as required by executing processes. In some embodiments, processor 340 is configured to execute application 362 based on OS 361 or via signals received from an eNB or operator. Processor 340 is further coupled to I / O interface 345, which provides UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. I / O interface 345 is a communication path between this peripheral and processor 340.

[0039] Processor 340 is also coupled to a touchscreen 350 and a display 355. An operator of UE 116 can use touchscreen 350 to input data into UE 116. Display 355 may be, for example, a liquid crystal display, light emitting diode display, or other display capable of rendering text and / or at least limited graphics from a website.

[0040] 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).

[0041] While Figure 3 illustrates one embodiment of the UE 116, various changes may be made to Figure 3. For example, various components of Figure 3 may be combined, further subdivided, or omitted, and additional components may be added as needed. As a specific example of one embodiment, the 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). Also, while Figure 3 illustrates the UE 116 configured as a mobile phone or smartphone, the UE may be configured to operate as other types of mobile or fixed devices.

[0042] The present invention 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) representing transmissions from a base station or one or more transmission points to a UE, and an uplink (UL) representing transmissions from the UE to a base station or one or more reception points.

[0043] 4G(4 thEfforts are underway to develop improved 5G (or pre-5G) communication systems to meet the increasing demand for wireless data traffic since the commercialization of the 4G (first generation) communication system. For this reason, 5G (or pre-5G) communication systems are referred to as "Beyond 4G networks" or "Post-LTE systems." To achieve higher data transmission rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., the 28 GHz or 60 GHz bands). To reduce radio wave loss and increase transmission distances, technologies being discussed for 5G communication systems include beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large-scale antennas. Furthermore, to improve the system network, the 5G communication system includes technological developments such as advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, cooperative communications, CoMP (Coordinated Multi-Points), and receiver-end interference cancellation.For 5G systems, advanced coding modulation (ACM) technologies such as hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) are being developed, as well as advanced access technologies such as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA).

[0044] The time unit for DL ​​signaling or UL signaling on a cell is called a slot, which can contain one or more slot symbols. A slot symbol can also be used as an additional time unit. A frequency (or bandwidth (BW)) unit is referred to as a resource block (RB). One RB contains multiple sub-carriers (SCs). For example, a slot can have a duration of 0.5 ms or 1 ms and can contain 7 symbols or 14 symbols, respectively, and an RB can contain 12 SCs with an interval between SCs of 15 kHz or 60 kHz, which can have a BW of 180 kHz.

[0045] DL signals include data signals carrying information content, control signals carrying DL control information (DCI), and reference signals (RS), also known as pilot signals. A gNB can transmit data information or DCI over a respective physical DL shared channel (PDSCH) or physical DL control channel (PDCCH). A gNB can transmit one or more of several RS types, including a channel state information RS (CSI-RS) and a demodulation RS (DMRS). The CSI-RS is intended for UEs to measure channel state information (CSI). The DMRS is transmitted only within the bandwidth of the respective PDCCH or PDSCH, and a UE can demodulate data or control information using the DMRS.

[0046] 4 is a diagram illustrating an exemplary DL slot structure 400 for PDSCH or PDCCH transmission according to an embodiment of the present invention. The embodiment of DL slot structure 400 illustrated in FIG. 4 is for illustrative purposes only. One or more of the components illustrated in FIG. 4 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention. As shown in FIG. 4, slot 410

[0047]

number

[0048] The DL system BW includes symbols 420, where the gNB transmits data information, DCI or DMRS.

[0049]

number

[0050] Each RB contains

[0051]

number

[0052] Contains SCs. For example,

[0053]

number

[0054] The UE transmits a total of

[0055]

number

[0056] M for SC430 PDSCH RBs are allocated. The PDCCH carrying DCI is transmitted via control channel elements (CCEs) that are spread over the DL system BW. For example, the first slot symbol 440 can be used by the gNB to transmit DCI and DMRS. The second slot symbol 450 can be used by the gNB to transmit DCI, data, or DMRS. The remaining slot symbols 460 can be used by the gNB to transmit PDSCH, DMRS, and CSI-RS associated with each PDSCH. In some slots, the gNB can also transmit synchronization signals and system information.

[0057] The UL signal further includes a data signal conveying information content, a control signal conveying UL control information (UCI), and an RS. The UE transmits data information or UCI via a respective PUSCH (physical UL shared channel) or PUCCH (physical UL control channel). When the UE transmits data information and UCI simultaneously, the UE can multiplex both on the PUSCH or transmit them separately on the respective PUSCH and PUCCH. The UCI includes hybrid automatic repeat request acknowledgment (HARQ-ACK) information indicating the UE's accurate or inaccurate detection of a data transport block (TB), a scheduling request (SR) indicating whether the UE has data in its buffer, and a CSI report that enables the gNB to select appropriate parameters for PDSCH or PDCCH transmission for the UE.

[0058] The CSI report from the UE may include a channel quality indicator (CQI) that informs the gNB of the maximum modulation and coding scheme (MCS) so that the UE can detect a data TB with a predetermined block error rate (BLER) (e.g., 10% BLER), a precoding matrix indicator (PMI) that informs the gNB how to precode signaling at the UE, and a rank indicator (RI) that indicates the transmission rank for the PDSCH. UL RSs include DMRS and sounding RS (SRS). DMRSs are transmitted only in the BW of each PUSCH or PUCCH transmission. The gNB can use the DMRS to demodulate information in each PUSCH or PUCCH. SRSs are transmitted by the UE to provide UL CSI to the gNB and to further provide PMI for DL ​​transmission in a TDD or flexible duplex system. UL DMRS or SRS transmissions can be based on transmission of Zadoff-Chu (ZC) sequences, or more generally, CAZAC sequences.

[0059] 5 is a diagram illustrating an exemplary UL slot structure 500 for PUSCH or PUCCH transmission according to an embodiment of the present invention. The embodiment of the UL slot structure 500 illustrated in FIG. 5 is for illustrative purposes only. One or more of the components illustrated in FIG. 5 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention. As shown in FIG. 5, slot 510

[0060]

number

[0061] The UL system BW includes symbols 520, where the UE transmits data information, UCI or RS, including one symbol transmitting DMRS 530.

[0062]

number

[0063] Each RB contains

[0064]

number

[0065] The UE includes a total of 10 SCs in the PUSCH transmission BW ("X" = "S") or PUCCH transmission BW ("X" = "C")

[0066]

number

[0067] M for SC540 PUXCH RBs are allocated. The last one or more slot symbols can be used to multiplex PUCCH or SRS transmissions from one or more UEs.

[0068] A hybrid slot, similar to a special SF, includes symbols for DL ​​transmission, one or more symbols for a guard period (GP), and symbols for UL transmission. For example, symbols for DL ​​transmission can carry PDCCH and PDSCH transmission, and symbols for UL transmission can carry PUCCH transmission. For example, symbols for DL ​​transmission can carry PDCCH transmission, and symbols for UL transmission can carry PUSCH and PUCCH transmission.

[0069] Figure 6 is a diagram illustrating an exemplary hybrid slot structure 600 for DL ​​and UL transmissions in accordance with an embodiment of the present invention. The embodiment of hybrid slot structure 600 illustrated in Figure 6 is for illustrative purposes only. One or more of the components illustrated in Figure 6 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0070] As shown in FIG. 6, a slot 610 is composed of a number of symbols 620, including symbols for DCI transmission and DMRS on each PDCCH 630, four symbols for data transmission on each PDSCH 640, a GP symbol 650 that provides a guard time for the UE to switch from DL reception to UL transmission, and a UL symbol for transmitting UCI on the PUCCH 660. In general, any division between DL and UL symbols of a hybrid slot is possible by sliding the position of the GP symbol from the second symbol of the slot to the last symbol of the slot. The GP may be shorter than one slot symbol, and additional time durations can be used for DL ​​transmission or UL transmission with shorter symbol durations. The GP symbol does not need to be explicitly included in the slot structure and, in practice, can be provided by the gNB scheduler by not scheduling transmissions to or from the UE on such symbols.

[0071] DL and UL transmissions can be based on orthogonal frequency division multiplexing (OFDM) waveforms, including a variant that uses DFT precoding known as DFT-spread-OFDM.

[0072] 7 is a diagram illustrating an exemplary transmitter structure 700 using OFDM according to an embodiment of the present invention. The embodiment of the transmitter structure 700 shown in FIG. 7 is for illustrative purposes only. One or more of the components shown in FIG. 7 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0073] 7, information bits such as DCI bits or data bits 710 are encoded by an encoder 720, rate-matched to the allocated time / frequency resources by a rate matcher 730, and modulated by a modulator 740. Then, the modulated encoding symbols and DMRS or CSI-RS 750 are mapped to SCs 760 by an SC mapping unit 765, subjected to an inverse fast Fourier transform (IFFT) 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 before being transmitted by a radio frequency (RF) unit 795.

[0074] 8 is a diagram illustrating an exemplary receiver structure 800 using OFDM according to an embodiment of the present invention. The embodiment of the receiver structure 800 shown in FIG. 8 is for illustrative purposes only. One or more of the components shown in FIG. 8 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0075] As shown in FIG. 8, a received signal 810 is filtered by a filter 820, a CP removal unit removes CPs 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, the received symbols are demodulated by a channel estimator and demodulator unit, a rate de-matcher 870 restores rate matching, and a decoder 880 decodes the resulting bits to provide information bits 890.

[0076] A UE typically monitors multiple candidate positions for each potential PDCCH transmission to decode multiple DCI formats within a slot. DCI formats include cyclic redundancy check (CRC) bits to ensure that the UE correctly detects the DCI format. DCI format types are identified by a radio network temporary identifier (RNTI) that scrambles the CRC bits. In the case of a DCI format that schedules a PDSCH or PUSCH for a single UE, the RNTI may be the cell RNTI (C-RNTI) and can act as a UE identifier.

[0077] In the case of a DCI format for scheduling a PDSCH carrying system information (SI), the RNTI may be SI-RNTI. In the case of a DCI format for scheduling a PDSCH providing a random access response (RAR), the RNTI may be RA-RNTI. In the case of a DCI format for providing a TPC command to a group of UEs, the RNTI may be TPC-PUSCH-RNTI or TPC-PUCCH-RNTI. Each RNTI type can be configured in the UE via higher layer signaling such as RRC signaling. A DCI format for scheduling PDSCH transmission for a UE is also referred to as a DL DCI format or DL ​​allocation, and a DCI format for scheduling PUSCH transmission from a UE is also referred to as a UL DCI format or UL grant.

[0078] 9 is a diagram illustrating an exemplary encoding process 900 for a DCI format according to an embodiment of the present invention. The embodiment of the encoding process 900 illustrated in FIG. 9 is for illustrative purposes only. One or more of the components illustrated in FIG. 9 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0079] As shown in FIG. 9, the gNB encodes and transmits each DCI format separately on each PDCCH. If applicable, the CRC of the DCI format codeword is masked to allow the UE to identify the DCI format using the RNTI for the UE for which the DCI format is intended. For example, the CRC and RNTI may include 16 bits. Alternatively, if the RNTI is not included in the DCI format, a DCI format type indicator field may be included in the DCI format. The CRC of the (uncoded) DCI format bits 910 is determined using a CRC calculation unit 920, and the CRC is masked using an XOR (exclusive OR) calculation unit 930 between the CRC bits and the RNTI bits 940. The XOR operation is defined as XOR(0,0) = 0, XOR(0,1) = 1, XOR(1,0) = 1, XOR(1,1) = 0. The masked CRC bits are added to the DCI format information bits using a CRC addition unit 950. After the encoder 960 performs channel coding (e.g., tail-biting convolutional coding or polar coding), the rate matcher 970 performs rate matching for the allocated resources. The interleaving and modulation unit 980 applies interleaving and modulation, such as QPSK, and the output control signal 990 is transmitted.

[0080] 10 is a diagram illustrating an exemplary decoding process 1000 for a DCI format for use with a UE according to an embodiment of the present invention. The embodiment of the decoding process 1000 illustrated in FIG. 10 is for illustrative purposes only. One or more of the components illustrated in FIG. 10 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0081] As shown in FIG. 10, the received control signal 1010 is demodulated and deinterleaved by the demodulator and deinterleaver 1020. The rate matching applied by the gNB transmitter is restored by the rate matcher 1030, and the resulting bits are decoded by the decoder 1040. After decoding, the CRC extractor 1050 extracts the CRC bits to provide the DCI format information bits 1060. The DCI format information is demasked 1070 by an XOR operation with the RNTI (1080, if applicable), and a CRC check is performed by unit 1090. If the CRC check is successful (checksum is 0), the DCI format information bits are considered valid. If the CRC check is not successful, the DCI format information bits are considered invalid.

[0082] A PDCCH transmission consists of RBs and symbols of a control resource set. A UE can be configured with RBs and symbols for one or multiple control resource sets. The PDCCH is transmitted using an aggregation of one or multiple control channel elements (CCEs). A block of encoded and modulated symbols in the DCI format is sequentially mapped to resource elements (k, l) via SC index k and slot symbol l on the associated antenna port that is part of the CCE allocated for PDCCH transmission. PDCCH transmission can be distributed in frequency, which is then referred to as an interleaved PDCCH transmission, or it can be localized in frequency, which is then referred to as a non-interleaved PDCCH transmission.

[0083] For example, l∈{0,1}. The PDCCH search space may be common to all UEs, or may be unique to all UEs. RNTIFor example, in the case of a common search space, Yk is set to 0 for two CCE aggregation levels L=4 and L=8, while the UE-specific search space at CCE aggregation level L is set to 0 for two CCE aggregation levels L=4 and L=8.

[0084]

number

[0085] If , the variable Y k teeth

[0086]

number

[0087] is defined by

[0088]

number

[0089] A=39827, D=65537, and k is the slot number. For example, for a set level of L CCEs, N CCE,k The position of the CCE relative to PDCCH candidate m in subframe k containing the CCE is

[0090]

number

[0091] If a UE is not configured with a C-RNTI, the search space is common to all UEs.

[0092] A key objective in the design of PDCCH transmissions is to improve their reliability. This can be achieved through a number of mechanisms, including frequency diversity or beamforming support, enabling accurate channel estimation, improved coverage, and minimizing the size of the DCI format. The reliability of PDCCH transmissions is improved because there is a lower likelihood of inaccurate decoding of the PDCCH, which conveys a DCI format that schedules data transmissions to or from one or more UEs. Since fewer resources need to be used, the overhead for PDCCH transmissions is reduced, allowing more resources to be used for data transmission. Furthermore, DCI formats can enable dynamic switching of transmission modes while minimizing the associated payload.

[0093] PDCCH transmission needs to be scheduled with reduced latency and improved reception reliability. This means that PDSCH transmission typically involves a small number of symbols, and therefore PDCCH transmission carries a small transmission block size, and PDCCH may exhibit material overhead. In this case, it is important to minimize the overhead associated with PDCCH transmission by making the DMRS used for PDCCH demodulation reusable for PDSCH demodulation.

[0094] A UE communicating with a gNB must perform time tracking and frequency tracking to maintain reliable communication with the gNB. Typically, this is achieved by the gNB transmitting an RS that the UE can use for time tracking and frequency tracking. To minimize the overhead associated with transmitting such an RS, it is preferable that the RS is not transmitted continuously (or even periodically), and that the RS is also used for other functions, such as a DMRS used for PDCCH demodulation.

[0095] Therefore, there is a need to design a PDCCH transmission that allows frequency diversity with enhanced channel estimation. There is a need to design a PDCCH transmission that allows beamforming and enhanced channel estimation. There is a need to enable DMRS reuse for demodulation of PDCCH and PDSCH transmissions. Furthermore, there is a need to enable configurable CCE aggregation levels for PDCCH transmissions in a common search space. Finally, there is another need to enable DMRS reuse for time tracking and frequency tracking and demodulation of PDCCH transmissions.

[0096] In some embodiments, a CCE structure for distributed PDCCH transmission that depends on the respective aggregation levels is considered to enable frequency diversity and enhanced channel estimation. Using a small CCE aggregation level typically relates to UEs experiencing a relatively high SINR, while using a large CCE aggregation level typically relates to UEs experiencing a relatively low SINR. Channel estimation accuracy is highly dependent on SINR; the lower the SINR, the poorer the channel estimation accuracy, and the greater the degradation in PDCCH reception reliability due to inaccurate channel estimation. Conversely, frequency diversity is a characteristic of the PDCCH transmission structure that is independent of SINR. Therefore, the design objective is to enable sufficient frequency diversity while simultaneously increasing the accuracy of channel estimation as the CCE aggregation level for the associated PDCCH transmission increases. Typically, frequency diversity of approximately two or four orders of magnitude is sufficient to capture almost all of the frequency diversity gain provided by the channel medium.

[0097] In the following description, it is assumed that one CCE includes four RBs, but other numbers of RBs, such as six RBs, can also be used. For frequency-distributed PDCCH transmission including one CCE or four RBs, the RBs can be distributed in frequency and not adjacent in frequency. This allows PDCCH transmission to capture almost all the frequency diversity gain that the channel medium can provide, but the DMRS used for channel estimation must be limited to each RB, and it is generally not advantageous for the UE to filter the channel estimate obtained across the frequency-distributed RBs. RBs correspond to resource element groups (REGs).

[0098] In the case of frequency-distributed PDCCH transmission including two CCEs or eight RBs, channel estimation can be improved by distributing four pairs of RBs in frequency. Then, when demodulating a PDCCH candidate including two CCEs, the UE can filter the DMRS in the RB pairs, assuming the same DMRS precoding in each pair of RBs, to improve the reliability of each channel estimation. Similarly, in the case of frequency-distributed PDCCH transmission including four CCEs or eight CCEs, corresponding to 16 or 32 RBs, respectively, transmission can be performed in four RB blocks or eight RB blocks (four individual frequency positions assuming a transmission bandwidth greater than 32 RBs).

[0099] The UE can then filter the DMRS within each block of RBs, improving the reliability of each channel estimation and allowing the associated PDCCH transmission to obtain all frequency diversity gains from the channel medium. Furthermore, frequency-distributed PDCCH transmissions can consist of blocks of RBs starting from an aggregation level of one CCE. For example, if a CCE includes six RBs, a PDCCH transmission for a UE with an aggregation level of one CCE can consist of two RB blocks across three frequency-discontinuous blocks of two RBs in the DL system bandwidth configured for PDCCH transmission for the UE. Generally,

[0100]

number

[0101] For a CCE containing N RBs, the UE uses N RBs to form a block of frequency-contiguous RBs. bundle RBs, and the distributed CCE-to-RB mapping is

[0102]

number

[0103] N frequency distribution blocks bundleRB N bundle A control resource set may consist of an RB block, e.g., a control resource set containing one symbol,

[0104]

number

[0105] and N bundle If =2,

[0106]

number

[0107] There is a frequency dispersion block,

[0108]

number

[0109] and N bundle =6,

[0110]

number

[0111] In the case of N bundle There is only one block of =6 frequency-contiguous RBs. If a given DMRS antenna port is an RB, the UE can assume that the same precoder is applied to all RBs in the RB bundle. Furthermore, the RB bundle is

[0112]

number

[0113] It can be bigger. This can be useful, for example, for transmitting UE common PDCCH in a common search space (CSS), where the DMRS may be common to the UE. total For PDCCH transmission on a control resource set spanning a BW of N RBs, the UE total , or N tota l / 2 or N total 1 / 4, which allows the UE to filter the DMRS for a larger number of RBs to improve channel estimation.

[0114] For CSS, Nbundle may be predefined in system operation or signaled by broadcast system information such as a master information block (MIB) or a secondary system information block (SIB). For example, a PDCCH scheduling transmission of the first SIB may have a bundle size predefined in system operation, while a PDCCH scheduling transmission of the second SIB or RAR may have a bundle size signaled in the first SIB.

[0115] CCEs can be transmitted over one OFDM symbol. By using a larger CCE aggregation level for PDCCH transmission and distributing each CCE over the OFDM symbols, coverage enhancement can be obtained if needed. For example,

[0116]

number

[0117] For a DL control resource set containing OFDM symbols and PDCCH candidates corresponding to an aggregation level of L CEs, CCEi, i=0,...,L-1 is the frequency-first REG-to-CCE mapping.

[0118]

number

[0119] The vectors can be located in OFDM symbols having indices determined by:

[0120]

number

[0121] For a DL control resource set containing RBs, the block of the first RB is index

[0122]

number

[0123] and the block of the second RB can start with the RB having index

[0124]

number

[0125] and the block of the third RB can start with the RB having index

[0126]

number

[0127] The block of the fourth RB can start with the RB having index

[0128]

number

[0129] where O is a UE-specific offset or a cell-specific offset, which can be determined, for example, from the C-RNTI for the UE, or explicitly configured using higher layer signaling by the gNB, or determined by the identity of the cell from which the PDCCH is transmitted.

[0130] 11 is a diagram illustrating an exemplary distributed PDCCH transmission structure 1100 depending on each CCE aggregation level according to an embodiment of the present invention. The embodiment of the distributed PDCCH transmission structure 1100 shown in FIG. 11 is for illustrative purposes only. One or more of the components shown in FIG. 11 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied by one or more processors that execute instructions to perform the functions described. Other embodiments may be used without departing from the scope of the present invention.

[0131] In the case of PDCCH transmission with an aggregation level of one CCE including four RBs, the RBs are distributed in frequency by a single RB (1110). In the case of PDCCH transmission with an aggregation level of two CCEs and time-prioritized mapping of the CCEs, each of the eight RBs is distributed in frequency by two adjacent RB blocks, where the first RB in the block of RBs is located on the first OFDM symbol for the first CCE and the second RB in the block of RBs is located on the second OFDM symbol for the second CCE (1120).

[0132] In the case of PDCCH transmission with an aggregation level of two CCEs and frequency-first mapping of CCEs, each of the eight RBs is frequency-distributed among two adjacent RB blocks, each of which is located on the same OFDM symbol (1130). A similar structure can be applied to PDCCH transmission with a CCE aggregation level greater than two CCEs. In time-first mapping, if there are fewer OFDM symbols than CCEs for the CCE aggregation level, for example, if there are two OFDM symbols for mapping an aggregation level of four CCEs, wraparound can be applied to CCE mapping (1140).

[0133] The mapping of CCEs to RBs in Figure 11 considers interleaving of RBs on an OFDM symbol-by-OFDM symbol basis to obtain dispersed (non-contiguous) RB indices in the physical domain from adjacent (contiguous) RB indices in the logical domain that form the CCE. If interleaving were not on an OFDM symbol-by-OFDM symbol basis but instead over two OFDM symbols, it would not be possible to place the RBs for a given CCE within a single OFDM symbol.

[0134] Different CCE mappings to OFDM symbols can be configured for different PDCCH transmission types. For example, time-first mapping can be applied to beamforming localized PDCCH transmission for a UE to maximize the localization of the beamforming PDCCH transmission and maximize the associated precoding gain, while time-first mapping can be applied to frequency-distributed PDCCH transmission using transmitter antenna diversity to maximize the frequency diversity gain.

[0135] In the case of a PDCCH transmission with an aggregation level of one CCE including four RBs and time-prioritized CCE-to-REG mapping, the RBs of the REG bundle are time-distributed for each prioritized OFDM symbol.

[0136]

number

[0137] Less than

[0138]

number

[0139] If we have OFDM symbols, N bundleWrap-around is applied to the RBs in the time domain,

[0140]

number

[0141] The RB is adjacent to the first RB in the first OFDM symbol,

[0142]

number

[0143] The RB is adjacent to the second RB in the first OFDM symbol,

[0144]

number

[0145] The RB is the second OFDM adjacent to the first RB, and so on.

[0146]

number

[0147] An RB is adjacent to p-1 RBs in q OFDM symbols. 12 is a diagram illustrating an exemplary localization PDCCH transmission structure 1200 depending on each CCE aggregation level according to an embodiment of the present invention. The embodiment of the localization PDCCH transmission structure 1200 illustrated in FIG. 12 is for illustrative purposes only. One or more components illustrated in FIG. 12 may be embodied in specialized circuitry configured to perform the noted functions, or one or more components may be embodied by one or more processors that execute instructions to perform the noted functions. Other embodiments may be used without departing from the scope of the present invention. As shown in Figure 12, the DL control resource set is

[0148]

number

[0149] If the DL control resource set includes 1210 symbols and the PDCCH transmission has an aggregation level of one CCE including four RBs, the first and third RBs are mapped contiguously in frequency from the first OFDM symbol, and the second and fourth RBs are mapped contiguously in frequency from the second OFDM symbol for each PDCCH candidate.

[0150]

number

[0151] If the PDCCH transmission has an aggregation level of one CCE including four RBs (1220), the first, second, third, and fourth RBs are mapped to the same RB index on the first, second, third, and fourth OFDM symbols, respectively. The PDCCH candidates are frequency-distributed.

[0152] CCE mapping such as that shown in Figure 11 or Figure 12 can allow coexistence of UEs with different bandwidth reception capabilities in the same bandwidth and coexistence of a common search space and a UE-specific search space in the same DL control resource set.

[0153] A UE may be configured to monitor different DL control resource sets associated with different search spaces in different symbols of a slot or in different slots. This configuration may be achieved by UE group common upper layer signaling or by UE-specific upper layer signaling. For example, a 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 slot and to monitor a second DL control resource set associated with a UE-specific search space in the second one or more symbols of the slot (e.g., after the first one or more symbols of the slot).

[0154] For example, a UE may be configured to monitor a first DL control resource set associated with a first common search space in a first one or more symbols of a slot, and may be individually configured to monitor a second DL control resource set associated with a second common search space in a second one or more symbols of the slot (e.g., immediately after the first one or more symbols of the slot). For example, a UE may be configured to monitor a first DL control resource set associated with a first UE-specific search space in a first one or more symbols of a slot, e.g., for transmission from a first beam, and may be configured to monitor a second DL control resource set associated with a second UE-specific search space in a second one or more symbols of the slot (e.g., immediately after the first one or more symbols of the slot).

[0155] For example, a UE may be configured to monitor a first DL control resource set according to parameters such as PDCCH candidates or a transmission scheme such as distributed or localized PDCCH transmission related to a common search space in a first number of slots within a slot period, and further monitor a first DL control resource set according to parameters related to a UE-specific search space in a second number of slots within the slot period. The slot period may be determined by system operation, such as 10 or 20 slots, or may be configured for the UE by UE group-wide or UE-specific higher layer signaling. Monitoring the search space by the UE means that the UE performs a decoding operation on the PDCCH candidates using each CCE in the search space.

[0156] A UE can monitor UE-specific DCI formats in the common search space and the UE-specific search space. To enable this function, the UE can adjust parameters for receiving UE-specific DCI formats in a control resource set according to the associated search space type (common or UE-specific). For example, a sequence for scrambling a DMRS transmission associated with a UE-specific DCI format transmission in a PDCCH can be a first scrambling sequence if the transmission is in the common search space, and a second scrambling sequence if the transmission is in the UE-specific search space. For example, the number of subcarriers used for MRS transmission in an RB can have a first value in the common search space and a second value in the UE-specific search space. For example, a first transmission scheme, such as transmit antenna diversity for distributed PDCCH transmission, can be associated with receiving a DCI format in the common search space, and a second transmission scheme, such as precoding / beamforming for localized PDCCH transmission, can be associated with receiving a DCI format in the UE-specific search space.

[0157] The UE may further be configured to monitor a first search space having a first period and a second search space having a second period. For example, the first search space may be a common search space and the period may be five slots, and the second search space may be a UE-specific search space and the period may be one slot. For example, the first search space may be a first UE-specific search space and the period may be one slot, and the second search space may be a second UE-specific search space and the period may be 1 / 5 or 1 / 2 of a slot. Therefore, the number of decoding operations that the UE can perform during a certain time period may depend on the number of search spaces that the UE monitors during that period.

[0158] For example, in a time period in which the UE does not monitor the common search space, the associated PDCCH decoding operation may be used to monitor the UE-specific search space. The number of PDCCH candidates for at least some CCE aggregation levels for the UE-specific search space may be larger in a time period in which the UE does not monitor the common search space. For example, in a time period in which the UE does not monitor a UE-specific search space with a longer period, the corresponding PDCCH decoding operation may be assigned to monitoring the UE-specific search space with a shorter period. The number of PDCCH candidates for at least some CCE aggregation levels for a UE-specific search space with a shorter monitoring period may be larger in a time period in which the UE does not monitor a UE-specific search space with a longer monitoring period.

[0159] In each serving cell, the higher layer signaling configures the UE with P control resource sets. For a control resource set p (0 ≤ p < P), this configuration can include: subcarrier spacing and CP length; the first symbol index provided by the higher layer parameter CORESET-start-symb; the number of consecutive symbols provided by the higher layer parameter [CORESET-time-duration]; the set of resource blocks provided by the higher layer parameter CORESET-freq-dom; the CCE-to-REG mapping provided by the higher layer parameter CORESET-trans-type; and / or, in the case of an interleaved CCE-to-REG mapping, the REG bundle size provided by the higher layer parameter CORESET-REG-bundle-size; whether the PDCCH transmission provided by the higher layer parameter CORESET-CCE-REG-mapping-type is distributed or localized, or the antenna port QCL (quasi-collocation) provided by the higher layer parameter [CORESET-QCL-ConfigId].

[0160] For each serving cell and each DCI format for which the UE is configured to monitor the PDCCH, the UE is configured with the following associations for the control resource set: the set of control resource sets by the higher layer parameter DCI-to-CORESET-map; the number of PDCCH candidates per CCE aggregation level L for each control resource set within the set of control resource sets by the higher layer parameter CORESET-candidates-DCI; and / or, in non-DRX mode operation, the k p symbol monitoring period for each control resource set within the set of control resource sets by the higher layer parameter CORESET-monitor-period-DCI. Each control resource set is

[0161]

number

[0162] Monitoring period k p The tolerance of CCE in the control resource set p is

[0163]

number

[0164] The monitoring period includes a set of CCEs numbered up to . The monitoring period can be indexed (modularly) 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. The set of PDCCH candidates that a UE monitors is defined in terms of a PDCCH UE-specific search space. PDCCH UE-specific search space at CCE aggregation level L

[0165]

number

[0166] (eg, L∈{1,2,4,8,16}) is defined by the set of PDCCH candidates for CCE aggregation level L. If the UE is configured with the higher layer parameter cif-InSchedulingCell, the carrier indicator field value corresponds to cif-InSchedulingCell.

[0167] For a serving cell for which 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 the carrier indicator field. For a serving cell for which 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 the carrier indicator field.

[0168] For control resource set p and DCI format A (e.g., for P=2 control resource sets), PDCCH candidates in the search space for the serving cell corresponding to carrier indicator field value nCI

[0169]

number

[0170] The corresponding CCE is given by:

[0171]

number

[0172] A0=39827, A1=39829, D=65537; i=0,...,L-1; n CI is the carrier indicator field value if the UE is configured with a carrier indicator field for the serving cell on which the PDCCH is monitored; otherwise,

[0173]

number

[0174] is the total number of all n configured for CCE aggregation level L in control resource set p. CIvalue, the maximum number of PDCCH candidates that can be any of all configured DCI formats or a match for DCI format A

[0175]

number

[0176] and

[0177]

number

[0178] is n CI the number of PDCCH candidates that the UE is configured to monitor for aggregation level L for the serving cell corresponding to n RNTI are the RNTI values ​​used for each DCI format.

[0179]

number

[0180] is the different PDCCH monitoring period k p Because they can be different from each other,

[0181]

number

[0182] The value can vary depending on the PDCCH monitoring period, and therefore

[0183]

number

[0184] teeth

[0185]

number

[0186] can be replaced by:

[0187]

number

[0188] is the PDCCH monitoring period k p All n configured for CCE aggregation level LDP in control resource set p CI value, be the maximum number of PDCCH candidates for any of all configured DCI formats or only for DCI format A; otherwise,

[0189]

number

[0190] is the total number of all n configured for CCE aggregation level L in control resource set p. CI It may be the maximum number of PDCCH candidates among all configured DCI formats for the value and for all nested PDCCH monitoring periods.

[0191] A UE configured to monitor PDCCH candidates in a given serving cell with a given DCI format size, carrier indicator field, and CRC scrambled by the C-RNTI (PDCCH candidates can have one or more possible values ​​of the carrier indicator field for the given DCI format size) can assume that a PDCCH candidate with a given DCI format size can be transmitted in the given serving cell within any PDCCH UE-specific search space corresponding to any of the possible carrier indicator field values ​​for the given DCI format size.

[0192] Because the PDCCH transmission scheme may differ from the PDSCH transmission scheme and the PDCCH transmission bandwidth may differ from the PDSCH transmission bandwidth, it is generally not possible to use the same DMRS for PDCCH and PDSCH demodulation. For example, PDCCH transmission to a UE may be performed in a first bandwidth without hierarchical spatial multiplexing, while PDSCH transmission to a UE may be performed in a second bandwidth with hierarchical spatial multiplexing.

[0193] To reduce the overhead associated with the first DMRS transmission for PDCCH demodulation and the second DMRS transmission for PDSCH demodulation, especially in transmissions of small data transmission 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. Furthermore, the PDCCH transmission bandwidth may be included within the PDSCH transmission bandwidth.

[0194] Figure 13 is a diagram illustrating an example PDCCH transmission and PDSCH transmission 1300 using the same DMRS for demodulation according to an embodiment of the present invention. The embodiment of PDCCH transmission and PDSCH transmission 1300 shown in Figure 13 is for illustrative purposes only. One or more of the components shown in Figure 13 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied by one or more processors that execute instructions to perform the functions described. Other embodiments may be used without departing from the scope of the present invention.

[0195] As shown in FIG. 13, PDCCH transmission is performed over a first OFDM symbol, and PDSCH transmission is performed over first and second OFDM symbols (1310). PDCCH transmission is performed over multiple RBs that are a subset of multiple RBs for PDSCH transmission. For example, the RBs for PDCCH transmission may be the center C RBs of D≧C RBs for PDSCH transmission. PDCCH RB 1320 and PDSCH RB in the first OFDM symbol each include subcarriers used for DMRS transmission in addition to subcarriers used for transmitting control information and data information. For example, one subcarrier out of every three subcarriers can be used for DMRS transmission. PDSCH RB 1340 in the second OFDM symbol does not include subcarriers used for DMRS transmission. To demodulate PDCCH or PDSCH transmission, the UE can filter DMRS subcarriers in both the RBs used for PDSCH transmission and the RBs used for PDCCH transmission in the first symbol.

[0196] This further reduces UE computational complexity and power consumption because the UE only needs to obtain a single channel estimate to demodulate the PDCCH transmission and PDSCH transmission. For DMRS filtering through RBs in the first OFDM symbol to provide an effective channel estimate, the DMRS must use the same precoding across all RBs in the first OFDM symbol, and the same precoding must also be used for the PDCCH transmission and the PDSCH transmission. For example, both the PDCCH transmission and the PDSCH transmission may be based on the same transmitter diversity scheme. For example, both the PDCCH transmission and the PDSCH transmission may be based on the use of the same precoding for beamforming transmission.

[0197] Because DMRS can be power-boosted to improve channel estimation, it can be advantageous not to place DMRS transmissions on the same subcarrier in the same slot symbol in adjacent cells, since mutual interference between power-boosted DMRSs can generally negate the benefit of increased DMRS transmission power. Therefore, the location (subcarrier) used for DMRS transmission in an RB can be pseudo-random or can be indicated by the gNB, for example, via association with a synchronization signal sequence used by the gNB. The pseudo-random determination can be based on the identity of the cell in which the DMRS is transmitted.

[0198] For example, in a DMRS transmission from an antenna port on four equally spaced subcarriers in a RB consisting of 12 subcarriers, the subcarriers with DMRS transmission in the RB are

[0199]

number

[0200] where k=0,1,2,3.

[0201]

number

[0202] (

[0203]

number

[0204] (where Λ is the cell ID that the UE acquires from the initial synchronization process with the cell.) For example, for DMRS transmission from an antenna port on two equally spaced subcarriers in an RB consisting of 12 subcarriers, the subcarriers with DMRS transmission in the RB are

[0205]

number

[0206] where k=0,1.

[0207]

number

[0208] The indication by the gNB may be based on the sequence used to transmit a synchronization signal, such as a primary synchronization signal or a secondary synchronization signal. When distributed PDCCH transmission and localized PDCCH transmission can be multiplexed on the same DL control resource set, the distributed PDCCH transmission can be based on a transmit diversity scheme using precoder cycling, where the precoder can be associated with the localized PDCCH transmission in some RBs. In this case, the UE cannot assume that the DMRS of the PRB uses the same precoder in adjacent RBs in different slots or frequencies, and cannot use the DMRS for time tracking or frequency tracking.

[0209] To avoid this limitation by allowing the UE to use the DMRS associated with demodulation of PDCCH transmission for time tracking and frequency tracking, the UE can be notified in advance (by DMRS transmission) that the DMRS uses the same precoding in a predetermined slot or predetermined RB. The predetermined slot or predetermined RB may be defined in system operation, such as all slots or all RBs of a DL control resource set every 5 ms, or may be signaled by system information. For example, the predetermined slot or predetermined RB may be determined by the gNB transmitting a PDCCH that schedules the first system information block. Based on the assumption that the RBs of the predetermined DL control resource set and the DMRS transmission in the predetermined slot use the same precoding, the UE can perform time tracking or frequency tracking in addition to channel estimation using the DMRS.

[0210] For PDCCH transmit diversity schemes using precoder cycling, N bundle A precoder weight can be specified for each bundle of adjacent RBs. For example,

[0211]

number

[0212] and for two transmitter antennas, N of the first RB bundle The precoder in can be {1;1}, and N in the second RB bundle The precoder in can be {1;-1}, and N in the third RB bundle The precoder in can be {1;j}, and N in the 4th RB bundle The precoder in can be {1;-j}. Once the precoder applied to each RB bundle is known, the UE can remove the precoding and totalNon-precoded DMRS reception can be obtained via RBs, which can be used for other purposes such as wideband channel estimation or time tracking when received at different time instances.

[0213] 14 is a diagram illustrating an example operation 1400 in which a UE assumes identical DMRS precoding in a predetermined slot and in RBs of a predetermined DL control resource set according to an embodiment of the present invention. The embodiment of the operation 1400 shown in FIG. 14 is for illustrative purposes only. One or more of the components shown in FIG. 14 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied by one or more processors that execute instructions to perform the functions described. Other embodiments may be used without departing from the scope of the present invention.

[0214] As shown in Figure 14, the gNB transmits a DMRS on a DL control resource set (1410). The UE receives the DMRS (1420) and determines whether fixed DMRS precoding can be assumed for that slot (1430). This determination can be based on a predetermined slot period or on a slot pattern signaled by system information from the gNB (e.g., using a time-periodically repeated bitmap). The RBs can include all RBs with DMRS transmission on the DL control resource set, or can be signaled by the gNB using higher layer signaling.

[0215] For example, if the RBs related to the common search space are not all RBs in the DL control resource set, the RBs may be those used for PDCCH transmission in the common search space. Furthermore, if the UE is configured with multiple DL control resource sets, the RBs may be those in a first DL control resource set that can further include transmission of UE group-common DL control signaling in the slot. If the UE cannot assume fixed DMRS precoding in the slot, the UE cannot use the DMRS received in the slot for time tracking or frequency tracking (1440). If the UE can assume fixed DMRS precoding in the slot, the UE can use the DMRS received in the slot for time tracking or frequency tracking (1450).

[0216] There may be many transmission schemes for PDSCH transmission relative to PUSCH transmission. If the transmission scheme is configured by higher layer signaling, the UE may monitor a DCI format including only fields required for the transmission scheme, and different DCI formats may be associated with different transmission schemes.

[0217] While offering operational simplicity, semi-static configuration of the transmission scheme for the PDSCH or PUSCH is disadvantageous because the gNB cannot quickly adapt the transmission scheme for the UE based on, for example, channel medium changes experienced by the UE; instead, the UE must rely on reconfiguration via higher layer signaling. If dynamic adaptation between a set of multiple transmission schemes is based on the use of a set of multiple DCI formats each having multiple sizes, the UE must decode each of the multiple DCI formats in each slot to determine the transmission scheme to be used for each PDSCH transmission or PUSCH transmission. This increases the number of decoding operations the UE must perform per slot, for example, by the same factor as the number of multiple DCI formats with different sizes. Alternatively, a single DCI format including a flag indicating each transmission scheme can be used so that the UE can decode a single DCI format per slot.

[0218] If scheduling of PDSCH or PUSCH transmissions using one transmission scheme does not require all fields of the DCI format or requires fields with a reduced number of bits, the trade-off for the reduced number of decoding operations is intermittent unnecessary overhead. The transmission schemes that can be associated with a single DCI format can be transmission schemes requiring a similar number of bits, such as up to 20% fewer bits than the transmission scheme requiring the largest number of bits, and the size of the DCI format is determined.

[0219] In order to reduce the overhead associated with introducing a flag in a DCI format that can indicate multiple transmission schemes, such as more than two transmission schemes, the flag may have a nested structure and may contain only one additional bit compared to the number of bits required to schedule a PDSCH transmission or a PUSCH transmission in one transmission scheme, designated as the first transmission scheme, which requires the largest number of bits in the DCI format.

[0220] This flag is located at the beginning of the DCI format. The UE may first check the value of the binary flag. If the flag value is a first value, the UE may determine that the transmission scheme of the associated PDSCH or PUSCH transmission is the first transmission scheme. If the flag value is a second value, the UE may determine the number of additional bits of the DCI format that are not used for scheduling according to the first transmission scheme, and the flag may function as an extended flag. For example, if the flag value is a second value, the additional bits may be located after the flag and at the end of the DCI format (the last bit of the DCI format). For example, if there are two fewer bits than in a second transmission scheme that requires more bits in the second than in a first transmission scheme, the value of the two bits may be used to indicate whether the DCI format schedules the respective PDSCH or PUSCH transmission in any of the second, third, fourth, or fifth transmission schemes.

[0221] 15 is a diagram illustrating exemplary operations 1500 for a DCI format including a binary flag for indicating one of multiple transmission schemes for PDSCH or PUSCH transmission according to an embodiment of the present invention. The embodiment of operations 1500 illustrated in FIG. 15 is for illustrative purposes only. One or more of the components illustrated in FIG. 15 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied by one or more processors that execute instructions to perform the functions described. Other embodiments may be used without departing from the scope of the present invention.

[0222] As shown in FIG. 15, 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 (1530) whether the value of the “Flag” field is “1.” If not, the UE receives (1540) an associated PDSCH or PUSCH transmission for the first respective transmission scheme. If yes, the UE determines (1550) whether a value for an additional bit included in the DCI format for scheduling for the first transmission scheme but not used for scheduling with any other transmission scheme is “1.” If no, the UE receives (1560) a PDSCH or PUSCH transmission for the respective second transmission scheme; otherwise, the UE receives (1570) a PDSCH or PUSCH transmission for the respective third transmission scheme.

[0223] A predetermined DCI format transmitted in a UE-specific search space, such as a first DCI format (fallback DCI format) monitored by the UE having a smaller magnitude than a second DCI format (non-fallback DCI format) monitored by the UE, can be used to provide fallback operation during a time period in which parameters for transmission to or from the UE are reconfigured by the gNB. For example, a DCI format scheduling a PDSCH transmission for a UE may include a field indicating a slot offset including a symbol within the slot, or a field indicating a resource for PUCCH transmission by the UE in response to receiving data conveyed by the PDCCH.

[0224] A UE may be configured with a slot offset set or a PUCCH source set by higher layers, and each field may indicate one value from each set. During a time period related to value reconfiguration in one or more such value sets, or before a value in such a value set is configured by UE-specific higher layer signaling, the UE may use a value indicated by UE group common system information. The UE may determine whether to use a value signaled by UE group common higher layer signaling (system information) or a usage value signaled by UE-specific higher layer signaling based on the associated DCI format. The UE detects a first DCI format, such as a fallback DCI format, and uses the latter value if it detects a second DCI format, such as a non-fallback DCI format.

[0225] Furthermore, the DCI formats may be identical and may be distinguished by the flag values ​​described in Figure 15. For example, the flag values ​​may correspond to the use of parameter values ​​such as a HARQ-ACK transmission timing offset or a PUCCH resource for HARQ-ACK transmission, or a slot timing offset for PDSCH or PUSCH transmission relative to a transmission slot for the associated DCI format signaled by the UE via UE common upper layer signaling. Thus, in addition to providing differentiation of the transmission scheme for the associated PDSCH or PUSCH transmission, the flag field of the DCI format may be configured by UE common upper layer signaling or may provide differentiation for the interpretation of values ​​relative to other fields of the DCI format depending on the value configured by UE common upper layer signaling.

[0226] To improve the flexibility of system operation and the reliability of PDCCH transmission, multiple CCE aggregation levels that a UE monitors in a common search space and multiple candidates for each CCE aggregation level can be configured by system information from a gNB. For example, the first system information block can indicate the number of CCE aggregation levels for PDCCH transmission and the number of candidates for each CCE aggregation level, which are used for UE group common information transmission, such as a random access response, scheduling paging, or a transmit power control command in a CSS. The first system information block can be scheduled to one CCE aggregation level of one or more predetermined CCE aggregation level sets, or the aggregation level for transmission scheduling for the first information block can be implicitly or explicitly indicated in the master information block.

[0227] An important objective in designing the PDCCH search space is to reduce the number of channel estimates that a UE must perform to decode PDCCH candidates, because this directly reduces the UE modem power consumption required to decode PDCCH candidates in each slot. This power consumption can account for a significant proportion (e.g., approximately 50%) of the overall UE modem power consumption when the UE is not in a discontinuous reception (DRX) state, since the UE must decode the PDCCH in all DL slots even when not scheduled for DL ​​reception or UL transmission. A nested S-type structure for the PDCCH search space is one approach to reducing the number of channel estimates that can be used to decode PDCCH candidates with a second CCE aggregation level that is smaller than the first CCE aggregation level, which may generally correspond to the maximum CCE aggregation level, when a channel estimate obtained to decode a PDCCH candidate with a first CCE aggregation level is used to decode a PDCCH candidate with a second CCE aggregation level that is smaller than the first CCE aggregation level.

[0228] 16 is a diagram illustrating an exemplary nested structure of PDCCH candidates 1600 according to an embodiment of the present invention. The nested structure embodiment of PDCCH candidates 1600 shown in FIG. 16 is for illustrative purposes only. One or more of the components shown in FIG. 16 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0229] As shown in FIG. 16, the UE can receive M packets for an aggregation level of L=8 CCEs in a PRB set or over the entire system BW. (8) = 2 candidates (1610, 1615), M for aggregation level of L = 4 CCEs (4) = 2 candidates 1620, M for aggregation level of L = 2 CCEs (2) = 6 candidates (1630, 1635), and M for aggregation level of L = 1 CCE (1) = 6 candidates 1640. M with L = 8 CCEs (8) The CCE indexes for the L=2 candidates may be consecutive as in Equation 1 or non-consecutive with an offset defined in Equation 2. The CCE indexes for the lower CCE aggregation level are M with L=8 CCEs. (8) The CCE index for the lower CCE aggregation level is a subset of M with L=8 CCEs as shown in FIG. (8) , or M with L=8 CCEs. (8) = 2 candidates each.

[0230] For example, as shown in Figure 16, a disadvantage of using a nested structure for CCE indexes is that the probability that a PDCCH cannot be transmitted to a UE increases because the associated CCEs have at least partially nested indices with CCEs used for PDCCH transmission to other UEs. For example, if the CCEs for PDCCH transmission to a first UE and the CCEs for PDCCH transmission to a second UE are nested with respect to candidates using the largest CCE aggregation level, such nesting may exist for PDCCH candidates using smaller CCE aggregation levels, and if PDCCH transmission to the first UE is performed using the largest CCE aggregation level, there may be few candidates with smaller CCE aggregation levels available for PDCCH transmission to the second UE.

[0231] For example, referring to FIG. 16, the first PDCCH transmission to the first UE is M with L=4 CCEs. (4) Since the CCEs for the first PDCCH candidate with L=8 CCEs for the second UE are fully nested with the CCEs for the first PDCCH candidate with L=8 CCEs for the second UE, PDCCH transmission to the second UE cannot use most of the remaining candidates for any CCE aggregation level. The increased blocking probability can essentially negate the potential benefit of the nested search space structure on UE power consumption because the UE must remain awake for a longer time to complete data transmission or reception.

[0232] A CCE for PDCCH transmission can be formed by multiple REGs, where one REG is equivalent to one RB for one OFDM symbol. Assuming that a CCE is the smallest resource unit for transmitting a DCI format at a given code rate and QPSK modulation, the number of REGs required for a CCE depends on the base DCI format size and the number of SCs in the RBs that can be used to transmit the DCI format (excluding SCs used for DMRS transmission). For example, if the DCI format size is 60 bits (or 76 bits including a 16-bit CRC) and the code rate is 2 / 3, 57 SCs are required for DCI format transmission. For two DMRS SCs per RB and 12 SCs per RB used for PDCCH transmission, approximately six REGs (or six RBs) are required in the CCE. For four DMRS SCs per RB and 12 SCs per RB used for PDCCH transmission, approximately seven REGs (or seven RBs) are required in the CCE. PDCCH transmission can be performed over a variable number of OFDM symbols, such as one, two, or three OFDM symbols.

[0233] The number of symbols can be configured by signaling from the physical layer or a higher layer. To improve spectrum efficiency and simplify the design for PDCCH transmission, design targets for mapping CCEs to REGs or PDCCHs to CCEs can include enabling multiplexing of distributed PDCCH transmission and localized PDCCH transmission on the same PRB set (or control resource set), or enabling all CCEs to be equivalent in terms of SCs available for PDCCH transmission, regardless of whether the PDCCH transmission spans one OFDM symbol or multiple OFDM symbols.

[0234] Therefore, there is a need to design a nested PDCCH search space structure for distributed and localized PDCCH transmissions.

[0235] There is a need to design a nested PDCCH search space structure with reduced PDCCH blocking probability.

[0236] Yet another need exists to define CCE to REG and PDCCH to CCE mappings for nested PDCCH search spaces across multiple slot symbols.

[0237] In one embodiment, a design for a nested PDCCH search space and a design that can reduce the blocking probability for PDCCH candidates of various CCE aggregation levels in the nested PDCCH search space are considered.

[0238] For PDCCH transmission, the associated blocking probability is typically benefited from PDCCH candidates for different CCE aggregation levels using different CCE indices. For example, for a PDCCH search space defined as in Equation 1, the CCE indices for PDCCH candidates are determined not only for each CCE aggregation level L but also for the number of candidates for each CCE aggregation level L.

[0239]

number

[0240] It also depends on. For a nested search space, the flexibility of the CCE index for the PDCCH candidate according to Equation 1 is substantially reduced because the CCE index must be common among multiple PDCCH candidates having different CCE aggregation levels. Furthermore, the CCE index for different PDCCH candidates having the same CCE aggregation level according to Equation 1 is deterministic. For example, in the case of the PDCCH search space according to Equation 1, the CCE index for PDCCH candidates having the same CCE aggregation level is a deterministic factor.

[0241]

number

[0242] is offset by Therefore, when a nested search space structure is used in which CCE indices for PDCCH candidates for different UEs are nested, the probability that multiple PDCCH candidates for a given CCE aggregation level are superimposed is substantially increased, and the blocking probability for PDCCH transmission to such a UE is consequently increased. Hereinafter, the CCE aggregation level is further defined as the UE configured for PDCCH reception, and is denoted as L. p (instead of L) is used, it is assumed that it can depend on the PRB set, also referred to as the control resource set. Also, the CCE aggregation level L p is L p =2 n , we assume that n=0,1,2,... is a power of 2.

[0243] In the first embodiment, the CCE index for the PDCCH candidate having a smaller CCE aggregation level than the maximum in the control resource set is determined with respect to the CCE index for the PDCCH candidate having the maximum CCE aggregation level in the control resource set.

[0244] The control mechanism for reducing the blocking probability of PDCCH transmissions to different UEs is the parameter Y in Equation 1. p,k The determination of the maximum CCE aggregation level is made by randomizing the CCE index for the PDCCH candidate having the maximum CCE aggregation level by depending on the index of the PDCCH candidate as well as the UE RNTI. Then, for example, if the CCE indices for PDCCH candidates having the maximum CCE aggregation levels for two UEs are nested, the probability of nesting for additional PDCCH candidates each having such a maximum CCE aggregation level due to the randomization of the CCE index according to the UE RNTI is reduced. For example, the CCE index and the maximum CCE aggregation level determined by Equation 1 are

[0245]

number

[0246] PDCCH candidate, candidate

[0247]

number

[0248] The CCE index for can be determined as follows:

[0249]

number

[0250] The same notation as in Equation 1 is applied.

[0251]

number

[0252] provides randomization for different candidates with the highest CCE aggregation level. For example,

[0253]

number

[0254] and

[0255]

number

[0256] A p,0=39827 and A p,1 =39831. A second mechanism for reducing the blocking probability of PDCCH transmissions to different UEs is to randomize the CCE indices for the PDCCH candidates by having a random offset between the last (or first) CCE index of consecutive 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. For example, the CCE index and maximum CCE aggregation level are determined by Equation 1.

[0257]

number

[0258] In the PDCCH candidates,

[0259]

number

[0260] The CCE index for can be determined as in Equation 3A or Equation 3B:

[0261]

number

[0262] Here, the same notation as in Equation 1 is applied, and f(m) is the PDCCH candidate m and the UE RNTI n RNTI It is a pseudorandom function with factors ≠ 0 (e.g., f(m) = m n RNRI ).

[0263] The first mechanism (different routing functions for different PDCCH candidates) and the second mechanism (UE-specific offset between consecutive PDCCH candidates) can also be combined.

[0264] In Equation 2 or Equation 3A / 3B, nesting may occur because the CCE indices for different PDCCH candidates having the same CCE aggregation level are random and not separated by a predetermined offset as in Equation 1. If the CCE indices for different PDCCH candidates having the same CCE aggregation level are separated by a predetermined offset as in Equation 1, nesting may occur. p,k,m When values ​​are determined to be at least partially nested, for example, based on Equation 2, adjustments can be applied to avoid such nesting.

[0265] For example, if CCE indices for different PDCCH candidates are nested, the UE may reuse the CCE indices determined in the last slot when the CCE indices for different PDCCH candidates are not nested. For example, if CCE indices for different PDCCH candidates are nested, the CCE indices for each applicable PDCCH candidate may be shifted by their respective minimum values ​​after the first time to prevent nesting with previous PDCCH candidates for the same CCE aggregation level. Furthermore, nesting of CCE indices may occur.

[0266] 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.

[0267]

number

[0268] In some embodiments of Case 1, where

[0269]

number

[0270] is CCE aggregation level L p <L p,max If valid for CCE aggregation level L p The CCE index for all PDCCH candidates with CCE aggregation level L p,max It is sufficient if the CCE indexes are a subset of all PDCCH candidates having the same CCE index.

[0271] CCE Aggregation Level L p <L p,max A limited approach to determining CCE indices for PDCCH candidates with CCE aggregation level L p,max Each of

[0272]

number

[0273] CCE aggregation level L among CCE indices of PDCCH candidates p <L p,max Total with

[0274]

number

[0275] Considering a substantially identical distribution for PDCCH candidates, CCE aggregation level L p The first one

[0276]

number

[0277] The CCE index for the candidate is CCE aggregation level L p,maxis a subset of CCE indices for the first PDCCH candidate having

[0278]

number

[0279] If

[0280]

number

[0281] The CCE index for the PDCCH candidate is the CCE aggregation level L p,max is a subset of CCE indices for the second PDCCH candidates having

[0282]

number

[0283] If , the CCE aggregation level L p Third

[0284]

number

[0285] The CCE index for the PDCCH candidate is the CCE aggregation level L p,max is a subset of CCE indices for the third PDCCH candidate having

[0286]

number

[0287] If the m-th CCE with aggregation level Lp is

[0288]

number

[0289] The CCE index for the PDCCH candidate is the CCE aggregation level L p,max is a subset of CCE indices for PDCCH candidates having CCE Aggregation Level L p against

[0290]

number

[0291] After determining the PDCCH candidates, the CCE index for each PDCCH candidate can be determined as shown in Equation 1, where N ECCE,p,k is L p,max can be replaced by

[0292]

number

[0293] The CCE index for the PDCCH candidate may be determined as in Equation 4:

[0294]

number

[0295] In Equation 4, Y p,k Y instead of p,k,m can also be used. CCE Aggregation Level L p,max The randomization of CCE indices for PDCCH candidates having a CCE aggregation level L is performed as shown in Equation 2 or Equation 3A / 3B. p <L p,max, where N is the CCE index for all CCE indices of the PDCCH source set. ECCE,p,k Instead of considering p,max Only the CCE index for each PDCCH candidate with .times. ...

[0296] 17 is a diagram illustrating an example process 1700 for determining CCEs for PDCCH candidates based on a first implementation example for a nested PDCCH search space structure according to an embodiment of the present invention. The embodiment of process 1700 for determining CCEs shown in FIG. 17 is for illustrative purposes only. One or more of the components shown in FIG. 17 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0297] As shown in Figure 17, the UE CCE,p,k A control resource set p having CCEs, and a CCE aggregation level L in the control resource set p p have

[0298]

number

[0299] PDCCH candidates are configured by the gNB. CCE,p,k for possible values ​​of

[0300]

number

[0301] and L p The value of can be determined by the system operation specification or can be derived by the UE by a predetermined formula.

[0302]

number

[0303] CCE aggregation level L p,max PDCCH candidates having

[0304]

number

[0305] , where f(m) is a function of PDCCH candidate m and may be set to 0 (1710).

[0306]

number

[0307] PDCCH candidates with CCE indices that are a subset of the CCE indices for

[0308]

number

[0309] Determine (1720). Lp ,max From the set of CCEs for PDCCH candidate m with

[0310]

number

[0311] As, L p <L p,max PDCCH candidates having

[0312]

number

[0313] Determine the CCE index for (1730). 18 is a diagram illustrating an exemplary CCE determination 1800 for PDCCH candidates based on a first approach of a first embodiment for a nested PDCCH search space structure according to an embodiment of the present invention. The embodiment of CCE determination 1800 shown in FIG. 18 is for illustrative purposes only. One or more of the components shown in FIG. 18 may be embodied in specialized circuitry configured to perform the referenced functions, or one or more of the components may be embodied by one or more processors executing instructions to perform the referenced functions. Other embodiments may be used without departing from the scope of the present invention.

[0314] As shown in Figure 18, the UE is configured to decode PDCCH candidates for four CCE aggregation levels corresponding to 1, 2, 4, and 8 CCEs.

[0315]

number

[0316] UE is

[0317]

number

[0318] Determine first and second sets of CCE indices for the candidate first PDCCH candidate 1810 and second PDCCH candidate 1815, respectively (eg, Equations 2 through 4 may be applied on an exemplary basis).

[0319]

number

[0320] is CCE aggregation level L p,maxThe first PDCCH candidate or CCE aggregation level L has 1820, 1830, and 1840. p,max The CCE indexes of the second PDCCH candidates are equally distributed among the CCE indexes of 1825, 1835, and 1845 (

[0321]

number

[0322] is even). CCE Aggregation Level L p <L p,max A second approach to determining CCE indices for PDCCH candidates with CCE aggregation level L p,max have

[0323]

number

[0324] CCE aggregation level L among CCE indices for each PDCCH candidate p <L p,max Total with

[0325]

number

[0326] Consider the configuration for the distribution of PDCCH candidates. This configuration can be provided by the gNB via higher layer signaling. For example,

[0327]

number

[0328] whereas CCE aggregation level Lp

[0329]

number

[0330] CCE indices for 2 / 3 of the PDCCH candidates with CCE aggregation level L p,max a subset of CCE indices for the first PDCCH candidate having a CCE aggregation level L p have

[0331]

number

[0332] The index for 1 / 3 of the PDCCH candidates is CCE aggregation level L p,max One configuration may indicate that the CCE indexes for the second PDCCH candidates are a subset of the CCE indexes for the second PDCCH candidates having the following characteristics:

[0333] The second approach is to determine the total number of CCEs in the control resource set p, N ECCE,p,k If is not large enough, it can cause an increased blocking probability, and furthermore, the CCE aggregation level L p,max This allows for additional control over blocking probability for UEs with RNTIs that can cause nesting of CCEs for different PDCCH candidates with RNTIs. The determination of CCE indexes for PDCCH candidates having different CCE aggregation levels according to the first embodiment is all L. p <L p,max against

[0334]

number

[0335] In order to simplify the determination of CCE indexes for the nested structure of PDCCH candidates, when the nested PDCCH structure is used in the first embodiment,

[0336]

number

[0337] and the UE ignores the configuration for the number of PDCCH candidates for each CCE aggregation level that does not satisfy that condition.

[0338]

number

[0339] So that L p,max A minimum number of additional virtual candidates for each PDCCH candidate can be assumed. The UE can be individually configured by a higher layer as to whether to assume a nested structure for the CCEs of PDCCH candidates for different aggregation levels, and can thereby determine a search space formula for the CCE indexes of the PDCCH candidates. The CCE structure for the UE common search space can be defined to have a conventional structure (search space) or a nested structure in the system operation specifications. At least one L p <L p,max against

[0340]

number

[0341] In one embodiment of Case 2, where the system operation is at least one CCE aggregation level L p,max1 <L p,max (For example, L p,max =8 and L p,max1 =4)

[0342]

number

[0343] If the CCE aggregation level L p,max1 the number of PDCCH candidates with

[0344]

number

[0345] The CCE index for the CCE aggregation level L p,max and the CCE aggregation level L p,max1 have

[0346]

number

[0347] CCE index for PDCCH candidate

[0348]

number

[0349] If the latter is not a subset of the CCE index, it can be determined as follows. In one embodiment,

[0350]

number

[0351] The CCE index for the PDCCH candidate is determined by L p,max L p,max1 Replace it with

[0352]

number

[0353] of

[0354]

number

[0355] By replacing it with

[0356]

number

[0357] It is sufficient if it is the same as one of Equations 2, 3A, or 3B for determining the CCE index for the PDCCH candidate. In one embodiment,

[0358]

number

[0359] To prevent potential nesting of CCE indices in PDCCH candidates,

[0360]

number

[0361] CCE index for PDCCH candidate

[0362]

number

[0363] Since it is determined to be different from the CCE index for the PDCCH candidate,

[0364]

number

[0365] The CCE index for the PDCCH candidate is determined by, for example, all the

[0366]

number

[0367] Considering PDCCH candidates, other

[0368]

number

[0369] CCE index and non-nested first CCE for PDCCH candidates

[0370]

number

[0371] This can be accomplished by selecting CCE indices for the PDCCH candidates. L p,max1 = 4 and L p,max2 = 2 such that L p,max2 <L p,max1 (and

[0372]

number

[0373] ) at least one CCE aggregation level L p,max2 Also for

[0374]

number

[0375]

number

[0376] In one embodiment, consider that:

[0377]

number

[0378] The CCE indexes for the PDCCH candidates can be determined as shown in Equation 4, for example.

[0379]

number

[0380] is L p,max L p,max1 Replace it with

[0381]

number

[0382] It can be further determined as shown in Equation 4 after considering the set of CCEs corresponding to the PDCCH candidates. In one embodiment, the CCE aggregation level L p,max2 The determination of the CCE index for the PDCCH candidate with the maximum CCE aggregation level is p,max1 and (L max,p Not)L p,max L p,max1 By replacing all

[0383]

number

[0384] It is considered that Equation 4 can be applied to PDCCH candidates. This results in a nested structure for determining the CCE index, where the CCE index for the PDCCH candidate with the largest CCE aggregation level in control resource set p is first determined from the set of all CCE indices in control resource set p, and the CCE index for the PDCCH candidate with the second largest CCE aggregation level in control resource set p is

[0385]

number

[0386] If so, it is determined only from the set of CCE indices for the PDCCH candidate with the highest CCE aggregation level; otherwise,

[0387]

number

[0388] from the set of CCE indices for the PDCCH candidate having the highest CCE aggregation level for the PDCCH candidate;

[0389]

number

[0390] is determined from the set of all CCE indices in control resource set p for PDCCH candidates with the same CCE aggregation level as described above (with possible adjustments to avoid nesting of CCE indices for PDCCH candidates with the same CCE aggregation level as described above), and the CCE index for the PDCCH candidate with the third and highest CCE aggregation level in control resource set p is

[0391]

number

[0392] if so, then it is determined only from the set of CCE indices for the PDCCH candidate with the first and largest CCE aggregation level; otherwise,

[0393]

number

[0394] from the set of CCE indices for the PDCCH candidate having the second largest CCE aggregation level for the PDCCH candidate;

[0395]

number

[0396] is determined from the set of all CCE indices in the control resource set p for that CCE, and so on. In the second case,

[0397]

number

[0398] In this case, the CCE aggregation level L p,max2 have

[0399]

number

[0400] The CCE indexes for the PDCCH candidates are, for example, L as shown in Equation 4. p,max1 L p,max1 The remaining PDCCH candidates can be determined by replacing

[0401]

number

[0402] The CCE index for p,max1 Instead of L p,max2 By using

[0403]

number

[0404] It can be determined for PDCCH candidates. In the second embodiment, the CCE index for the PDCCH candidate is determined based on the CCE index for the PDCCH candidate requiring the largest number of CCEs. The UE first counts the number of configured PDCCH candidates with CCE aggregation level Lp in the control resource set p.

[0405]

number

[0406] against

[0407]

number

[0408] Determine the maximum value for the product value of .

[0409]

number

[0410] The maximum value for

[0411]

number

[0412] and L p The values ​​are

[0413]

number

[0414] It is displayed as:

[0415]

number

[0416] The value of can be different for different control resource sets. p The maximum value is the same for all values.

[0417]

number

[0418] If there is a selected L p Values ​​like minimum or maximum L p It can be one of the following values: Then, the UE calculates, for example,

[0419]

number

[0420] Determine the CCE index for the PDCCH candidate. As a result, the number of CCEs is

[0421]

number

[0422] For example, referring to Equation 1, the PDCCH candidate

[0423]

number

[0424] The CCE for can be determined as in Equation 5:

[0425]

number

[0426] Then, the UE calculates N using, for example, Equation 1 or Equation 2. CCE,p,k N CCE,p,k,nest By replacing

[0427]

number

[0428] For example, referring to Equation 1, the CCEs for the PDCCH candidates may be determined as given in Equation 6:

[0429]

number

[0430] 19 is a diagram illustrating an example determination 1900 of CCEs for PDCCH candidates based on a second embodiment according to an embodiment of the present invention. The embodiment of CCE determination 1900 shown in FIG. 19 is for illustrative purposes only. One or more of the components shown in FIG. 19 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention. As shown in Figure 19, the UE CCE,p,k A control resource set p having CCEs and a CCE aggregation level L within the control resource set p p have

[0431]

number

[0432] The gNB configures N PDCCH candidates. CCE,p,k for the value

[0433]

number

[0434] and L p The value of can be determined in the system operation specification or can be derived by the UE by a predetermined formula.

[0435]

number

[0436] and L p Based on the value of

[0437]

number

[0438] (1910)

[0439]

number

[0440] For PDCCH candidates, the UE CCE,p,k Given a set of CCEs, determine 1920 the index of each CCE by a formula such as one of Equation 1 or Equation 2. Each

[0441]

number

[0442] For PDCCH candidates, the UE uses the set of available CCE indices

[0443]

number

[0444] By considering a set of CCE indices for PDCCH candidates, i.e., N CCE,p,k of

[0445]

number

[0446] , and determine each CCE index by a formula such as one of Equation 1 or Equation 2 (1930). 20 is a diagram illustrating exemplary CCE indexes 2000 of PDCCH candidates based on a second embodiment according to an embodiment of the present invention. The embodiment of CCE indexes 2000 illustrated in FIG. 20 is for illustrative purposes only. One or more of the components illustrated in FIG. 20 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied by one or more processors that execute instructions to perform the functions described. Other embodiments may be utilized without departing from the scope of the present invention. As shown in FIG. 20, the UE is configured with a CCE aggregation level of L p =1

[0447]

number

[0448] PDCCH candidate 1910, CCE aggregation level L p =2

[0449]

number

[0450] PDCCH candidate 1920, for CCE aggregation level Lp=4

[0451]

number

[0452] PDCCH candidate 1930 and CCE aggregation level L p =8

[0453]

number

[0454] There are 1940 PDCCH candidates.

[0455]

number

[0456] In slot k, the UE transmits all N packets in the control resource set p. CCE,p,k Considering CCE, CCE aggregation level L p =4

[0457]

number

[0458] Determine the CCE index for the PDCCH candidate (1950). The CCE index is N CCE,p,k,nest The UE forms a set of CCEs in control resource set p and slot k (1960). CCE,p,k,nest For CCE aggregation levels Lp=1, Lp=2, and Lp=8, respectively, from the CCE index in the CCE set

[0459]

number

[0460] and determining the CCE index for the PDCCH candidate. The parameter Y in Equation 1 p,k By adding the determination of L to the UE RNTI and making it dependent on the index of the PDCCH candidate, the CCE index for the PDCCH candidate can be further randomized as described for the first embodiment. For example, the CCE index is L p ≠L p,nest For the CCE index corresponding to N CCE,p,k Instead of N CCE,p,k,nest By using Equation 2 or Equation 3A / 3B (generally, L p,max L p,nest or DL p can be determined by

[0461] Furthermore, an additional condition that can be applied to both the first and second embodiments is not only to use different CCE indices for PDCCH candidates having the same CCE aggregation level, but also to use different CCE indices for PDCCH candidates having different CCE aggregation levels, if possible. This can be achieved by removing the CCE indices assigned to the PDCCH candidates from the available CCE index set and continuing in an iterative manner. For example, if the maximum CCE aggregation level and the total set of available CCE indices {S CCE,p,k}, and the set {S CCE,p,k,nest For example, the CCE aggregation level is L according to the first embodiment. p,max Or, according to the second embodiment,

[0462]

number

[0463] That's good. {S CCE,p,k,nest}In the set of CCE indices, L p,nest If different from the CCE aggregation level L p,max The index of the CCE for the PDCCH candidate having {S CCE,p,k,nest} to create a second CCE index set {S CCE,p,k,nest,1} can be determined. CCE,p,k,nest,1}In the set of CCEs, L p,nest If different, the second largest CCE aggregation level L p,max1 The index of the CCE for the PDCCH candidate having {S CCE,p,k,nest,1} to create a second CCE index set {S CCE,p,k,nest,2}, and so on. This process can continue until CCE indices for all PDCCH candidates at all CCE aggregation levels have been assigned, or until the available CCE index set does not contain enough CCE indices to assign to PDCCH candidates at the CCE aggregation levels without nesting. In the latter case, the first set of CCE indices {S CCE,p,k,nest}.

[0464] The second embodiment of the present invention considers mapping CCEs to REGs and mapping PDCCHs to CCEs by considering a nested PDCCH search space.

[0465] When a UE is configured with PDCCH candidates that map 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 to different OFDM symbols, such as the first OFDM symbol or the second OFDM symbol, the number of CCEs that can be used to map 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 across two OFDM symbols may be twice as large as the number of CCEs available for mapping PDCCH candidates to one OFDM symbol.

[0466] 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 the associated OFDM symbol, and all control resource subsets span the same BW as the control resource set. If all PDCCH candidates are mapped to all OFDM symbols in the control resource set (which may be the case when the control resource set contains only one OFDM symbol), a nested search space can be obtained as described in previous embodiments herein.

[0467] Figure 21 is a diagram illustrating an example control resource subset 2100 within a control resource set, according to an embodiment of the present invention. The embodiment of the control resource subset 2100 illustrated in Figure 21 is for illustrative purposes only. One or more of the components illustrated in Figure 21 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0468] As shown in Figure 21, a UE is configured with a set of PRBs (2110A and 2110B) for a control resource set spanning two OFDM symbols. The set of PRBs may include PRBs that are adjacent or non-adjacent in frequency. The first control resource subset includes all PRBs within the first OFDM symbol 2120, the second control resource subset includes all PRBs within the second OFDM symbol 2130, and the third control resource subset is identical to the control resource set and includes the first and second OFDM symbols.

[0469] For the exemplary implementation of the control resource subsets of FIG. 21, the number of CCEs in the first control resource subset is N CCE,p,k,1 and the number of CCEs in the second control resource subset is N CCE,p,k,2 and the number of CCEs in the control resource set is N CCE,p,k For example, N CCE,p,k,1 =N CCE,p,k,2 =N CCE,p,k / 2.

[0470] If different PDCCH candidates are mapped to different OFDM symbol indices including different numbers of OFDM symbols, the nested search space structure can be determined as follows: N P For a DL control resource set p containing j OFDM symbols, if CCEs are mapped to j OFDM symbols, the CCE aggregation level L p L p,j and j OFDM symbols (1≦j≦N p ) CCE aggregation level L p The number of PDCCH candidates for

[0471]

number

[0472] To define the nested search space structure, we consider the uniform distribution of CCEs for PDCCH candidates over j OFDM symbols and

[0473]

number

[0474] For example, L p,1 =4, L p,2 =2, L p,3 = 2 and L p,4 = 1. Alternatively, the integer value

[0475]

number

[0476] Only L can be considered. p =2 l , if l is a non-negative integer, L p,3 is not defined. UE first sets 1≦j≦N p is

[0477]

number

[0478] Determine the maximum value for the product value of

[0479]

number

[0480] Set.

[0481]

number

[0482] If there are multiple values ​​for

[0483]

number

[0484] or the smallest value j nest Generally, it is acceptable to have j nest teeth

[0485]

number

[0486] with 1≦j≦N p can be predicted to be the smallest value of

[0487]

number

[0488] is. For example, the UE calculates the following using Equation 1 or Equation 2:

[0489]

number

[0490] Determine the CCE index for the PDCCH candidate. If there are the same number of CCEs for each OFDM symbol,

[0491]

number

[0492] CCE indices for PDCCH candidates may be determined for CCE indices in the first OFDM symbol of DL control resource set p in slot k, and N CCE,p,k,1 , the remaining j nest CCEs within an OFDM symbol may have the same index as the first OFDM symbol. Furthermore, CCE indexing may be enabled on a symbol-by-symbol basis rather than across all symbols. As a result of the CCE index, the set

[0493]

number

[0494] For example, referring to Equation 1, in the first OFDM symbol of DL control resource set p in slot k, PDCCH candidates

[0495]

number

[0496] The CCE index set for can be determined as in Equation 7:

[0497]

number

[0498] Then, the UE calculates N OFDM symbols in the first OFDM symbol of the DL control resource set p in slot k using Equation 1 or Equation 2. CCE,p,k,1 CCE index set

[0499]

number

[0500] By replacing it with the CCE index set,

[0501]

number

[0502] Determine the CCE index for the PDCCH candidate. For example, referring to Equation 1,

[0503]

number

[0504] CCE index for PDCCH candidate,

[0505]

number

[0506] can be determined as in Equation 8:

[0507]

number

[0508] 22 is a diagram illustrating exemplary CCE indexes 2200 of PDCCH candidates over one or two OFDM symbols in a nested structure according to an embodiment of the present invention. The embodiment of CCE index 2200 shown in FIG. 22 is for illustrative purposes only. One or more of the components shown in FIG. 22 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0509] As shown in Figure 22, the UE is configured with a DL control resource set p spanning two symbols. p = 1 and L p All PDCCH candidates for L = 2 span one OFDM symbol, p = 4 and L p The PDCCH candidate for =8 spans two OFDM symbols. The UE selects the next PDCCH candidate, i.e., the first PDCCH candidate on the first OFDM symbol.

[0510]

number

[0511] On the second OFDM symbol

[0512]

number

[0513] On the first OFDM symbol

[0514]

number

[0515] and on the second OFDM symbol,

[0516]

number

[0517] It consists of:

[0518]

number

[0519] Therefore, the UE can calculate, for example, the first OFDM symbol 2210 using Equation 7.

[0520]

number

[0521] Determine the CCE set. For example, determine the CCE aggregation level L in the first OFDM symbol. p The first, second, third, fourth, fifth and sixth PDCCH candidates with .DELTA..times ...

[0522] The actual indexes of CCEs 1 to 12 in FIG. 22 may differ in the DL control resource set, but they are N CCE,p,k,1 Note that the CCE index is the index in the CCE set of N = 12. For the remaining PDCCH candidates, the CCE index is calculated using, for example, Equation 8. CCE,p,k,1 = 12, and CCEs 1, 4, 7 and 10 are the respective CCEs on the first OFDM symbol.

[0523]

number

[0524] CCEs 2 and 8 can be used for PDCCH candidates, respectively, on the second OFDM symbol.

[0525]

number

[0526] CCEs (2, 8) and (5, 11) can be used as PDCCH candidates, and CCEs (2, 8) and (5, 11) can be used as PDCCH candidates, respectively, on the second symbol.

[0527]

number

[0528] CCEs (3, 9) and (6, 12) on both symbols can be used for PDCCH candidates.

[0529]

number

[0530] can be used for PDCCH candidates, and furthermore, CCEs (1, 7), (3, 9), (4, 10) and (6, 12) on both symbols

[0531]

number

[0532] It can be used as a PDCCH candidate. The nested PDCCH search space structure is mainly applicable to distributed PDCCH transmission in which one or more REG blocks for a CCE can be distributed in frequency and PDCCH candidates can share a set of CCE indices. In localized PDCCH transmission in which REGs (and CCEs) for PDCCH candidates are contiguous in frequency, the nested search space structure increases the likelihood that a UE will select a CCE that experiences good channel conditions, but is more difficult to achieve when the CCEs for PDCCH candidates are distributed in frequency. For example, when the DL control resource set and CCE aggregation level L are allocated to one OFDM symbol, p = 1

[0533]

number

[0534] PDCCH candidates and CCE aggregation level L p = 2

[0535]

number

[0536] For PDCCH candidates,

[0537]

number

[0538] All PDCCH candidates

[0539]

number

[0540] CCE index

[0541]

number

[0542] For PDCCH candidates

[0543]

number

[0544] It can be a subset of the CCE index, but L p CCE for two PDCCH candidates with p = 1, which reduces the likelihood that the UE will select a CCE for PDCCH transmission that will experience good channel conditions.

[0545] The limitations of nested search space design for localization PDCCH transmission can be overcome by restricting the use of nested search space to distributed PDCCH transmission only and using an open search space design for localization PDCCH transmission, such as Equation 1. Nevertheless, to benefit from a reduction in channel estimation that the UE needs to calculate per slot, nested search space design can also be applied to localization PDCCH transmission.

[0546] In a first approach, in localized PDCCH transmission, the nested search space design can have a nested allocation of CCEs to PDCCH candidates, where the CCE index for the CCE aggregation level with the fewest number of candidates is nested with the CCE index for the CCE aggregation level with the second fewest number of candidates, the CCE index for the CCE aggregation level with the second fewest number of candidates is nested with the CCE index for the CCE aggregation level with the third fewest number of candidates, and so on.

[0547] In the second approach, CCE indices can be determined for distributed transmission, and some PDCCH candidates can have continuous CCEs in the frequency domain.

[0548] When the DL control resource set includes multiple OFDM symbols, PDCCH candidates for a larger CCE aggregation level, such as 4 or 8 CCEs, can be limited to span multiple OFDM symbols in order to limit the frequency span for the PDCCH candidates and reduce the number of RBs for which the UE needs to acquire channel estimates. PDCCH candidates for a smaller CCE aggregation level, such as one CCE, can have their REGs over only one OFDM symbol or over multiple OFDM symbols.

[0549] Also, although the transmission of distributed PDCCH candidates can be across one OFDM symbol (especially for smaller CCE aggregation levels) or across all OFDM symbols of the DL control resource set (especially for larger CCE aggregation levels), it is possible to configure the transmission of localized PDCCH candidates to be across all OFDM symbols regardless of the CCE aggregation level.

[0550] 23 is a diagram illustrating nested allocation of CCE indices 2300 for PDCCH candidates based on ascending PDCCH candidate order according to an embodiment of the present invention. The embodiment of nested allocation of CCE indices 2300 shown in FIG. 23 is for illustrative purposes only. One or more of the components shown in FIG. 23 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied by one or more processors that execute instructions to perform the functions described. Other embodiments may be used without departing from the scope of the present invention. As shown in Figure 23, the UE is configured with a DL control resource set p that spans one symbol. p = 1

[0551]

number

[0552] PDCCH candidate, CCE aggregation level L p = 2

[0553]

number

[0554] PDCCH candidate, CCE aggregation level L p = 4

[0555]

number

[0556] PDCCH candidates and CCE aggregation level L p = 8

[0557]

number

[0558] There are PDCCH candidates. For example, the UE may select the largest number of PDCCH candidates according to Equation 1.

[0559]

number

[0560] The UE may first determine 2310 the CCE index for the CCE aggregation level having

[0561]

number

[0562] Using a set of CCEs for PDCCH candidates, for example, L p = 1 using Equation 1

[0563]

number

[0564] The CCE index for the PDCCH candidate can be determined, which

[0565]

number

[0566] One CCE index for the PDCCH candidate may be obtained, and another CCE index for each PDCCH candidate may be determined as a respective next (previous) CCE index (2320). UE is

[0567]

number

[0568] Using a set of CCEs for PDCCH candidates, for example, L p = 1 using Equation 1

[0569]

number

[0570] The CCE index for the PDCCH candidate can be determined, whereby

[0571]

number

[0572] One CCE index for each PDCCH candidate can be obtained.

[0573]

number

[0574] The other three CCE indices for the PDCCH candidate may be determined from the previous three (or next three) CCE indices, respectively (2330 and 2335).

[0575]

number

[0576] Using a set of CCEs for PDCCH candidates, for example, L p = 1 using Equation 1

[0577]

number

[0578] The CCE index for the PDCCH candidate can be determined, whereby

[0579]

number

[0580] One CCE index for the PDCCH candidate can be obtained, and the other seven CCE indexes can be determined from the next seven (or previous seven) CCE indexes 2340. If there are not enough next (or previous) CCE indexes, the previous (or next) CCE index can be used.

[0581] 24 is a diagram illustrating nested allocation 2400 of CCE indices for PDCCH candidates based on a restriction on CCE indices for multiple PDCCH candidates according to an embodiment of the present invention. The embodiment of nested allocation 2400 of CCE indices shown in FIG. 24 is for illustrative purposes only. One or more of the components shown in FIG. 24 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied by one or more processors that execute instructions to perform the functions described. Other embodiments may be used without departing from the scope of the present invention. As shown in Figure 24, the UE is configured with a DL control resource set p that spans one symbol. p = 1

[0582]

number

[0583] PDCCH candidate, CCE aggregation level L p = 2

[0584]

number

[0585] PDCCH candidate, CCE aggregation level L p= 4

[0586]

number

[0587] PDCCH candidates and CCE aggregation level L p = 8

[0588]

number

[0589] The UE first calculates the CCE index for the CCE aggregation level determined by Equation 1.

[0590]

number

[0591] The UE can be determined as follows (2410, 2415).

[0592]

number

[0593] By using a set of CCEs for PDCCH candidates, for example, L p = 1 using Equation 1

[0594]

number

[0595] The CCE index for the PDCCH candidate can be determined, whereby

[0596]

number

[0597] One CCE index for each PDCCH candidate can be obtained (2420). UE is

[0598]

number

[0599] By using a set of CCEs for PDCCH candidates, for example, L p Using Equation 1, where =2

[0600]

number

[0601] The CCE index for the PDCCH candidate can be determined, whereby

[0602]

number

[0603] Two CCE indices for the PDCCH candidates can be obtained, and

[0604]

number

[0605] The UE may determine the other two CCE indices for the PDCCH candidate based on the previous two (or next two) CCE indices, respectively (2430).

[0606]

number

[0607] By using a set of CCEs for PDCCH candidates, for example, Lp Using Equation 1, where =2

[0608]

number

[0609] The CCE index for the PDCCH candidate can be determined, whereby

[0610]

number

[0611] Two CCE indices for the candidate can be obtained, and the other six CCE indices can be determined from the next six (or previous six) CCE indices 2440. If there are not enough next (or previous) CCE indices, the previous (or each) CCE index can be used. UL DMRS or SRS transmission can be based on the transmission of ZC sequences, CAZAC sequences, or pseudo-noise (PN) sequences. For example,

[0612]

number

[0613] For UL system BW of RB, ZC sequence

[0614]

number

[0615] teeth

[0616]

number

[0617] By the basic sequence

[0618]

number

[0619] can be defined by the cyclic shift (CS) of

[0620]

number

[0621] is the sequence length,

[0622]

number

[0623] and

[0624]

number

[0625] and the qth root ZC sequence is

[0626]

number

[0627] With q given by

[0628]

number

[0629] Given by

[0630]

number

[0631] have

[0632]

number

[0633] The length of the ZC sequence is defined by

[0634]

number

[0635] teeth

[0636]

number

[0637] is given by the largest decimal that satisfies Multiple RS sequences can be defined from a single base sequence using different values ​​of α. UL DMRS or SRS transmissions can have a comb spectrum in which non-contiguous SCs are used for transmission in slot symbols. SRS transmissions are identified by their respective sets of parameters, such as the transmit comb, cyclic shift, BW, starting position in the system BW, number of transmit antenna ports, timing offset for the first transmission, or number of transmit symbols.

[0638] The CSI-RS can be transmitted via multiple antenna ports, such as 1, 2, 4, 8, 12, or 16 antenna ports. In the case of CSI-RS using more than 8 antenna ports,

[0639]

number

[0640] The CSI-RS configuration is aggregated to

[0641]

number

[0642] Each CSI-RS configuration in such an aggregation can be obtained as

[0643]

number

[0644] This corresponds to an antenna port. The mapping of CSI-RS to REs in slots is described in the LTE specification. Multiple CSI-RS configurations can be used in one cell. A UE can be configured with multiple sets of CSI-RS, including up to three configurations for NZP CSI-RS that the UE can use for CSI reporting and zero or more configurations for ZP CSI-RS. The NZP CSI-RS configuration is provided by a higher layer. The ZP CSI-RS configuration for a slot can be provided by a derived bitmap.

[0645] The UE may be configured with one or more CSI-RS resource configurations, which may include the following parameters: In one embodiment, the one or more CSI-RS resource configurations include a CSI-RS resource configuration identity; in another embodiment, the one or more CSI-RS resource configurations include multiple CSI-RS processes. For example, the allowable values ​​and antenna port mappings may be similar to those described in the LTE specification; in yet another embodiment, the one or more CSI-RS resource configurations include a CSI-RS configuration as described in the LTE specification; and in yet another embodiment, the one or more CSI-RS resource configurations include the UE's assumption for the reference PDSCH transmit power for the CSI feedback Pc for each CSI process. C CSI,0 and C CSI,1When the CSI is configured by a higher layer for a CSI process, Pc is configured for each CSI slot set of the CSI process. In another example, one or more CSI-RS resource configurations may be configured using pseudo-random sequence generator parameters, n IDを In another example, if the UE is configured with the upper layer parameter eMIMO-Type and the eMIMO-Type is set to "CLASS A" for the CSI process as described in LTE specification, one or more CSI-RS resource configurations include a CDM type parameter.

[0646] A UE can be configured with one or more CSI resource configurations for interference measurement (CSI-IM). A UE is typically not expected to receive a CSI-IM resource configuration that does not completely overlap with one of the ZP CSI-RS resource configurations.

[0647] Based on the CQI calculation, the UE can derive a CQI index between 1 and 15 corresponding to a modulation scheme and transmission block size that the UE can receive with a predetermined value, e.g., a BLER not exceeding 10%. If this is not possible, the UE reports a CQI index of 0. The interpretation of the CQI index is shown in Table 1, although other mapping tables may also exist.

[0648] [Table 1]

[0649] A network can support UEs with different transmit or receive bandwidth capabilities. For example, a network may have an available system DL or UL BW of 200 MHz, while a particular category of UEs can be configured or configured to receive or transmit only in a bandwidth smaller than the system DL or UL BW, such as 20 MHz. Despite the UE's transmit or receive bandwidth being smaller than the system DL or UL BW, respectively, the gNB can schedule reception or transmission from the UE in any portion of the respective system bandwidth.

[0650] The gNB can configure UE narrowbands (NBs) for the DL system BW or UL system BW, where the BW of each NB does not exceed the UE's capability for reception or transmission, and each NB schedules transmissions to or from the UE. The NBs can have the same size or different sizes. For example, all NBs can have the same size except for the last NB, which can have the same or smaller size than the other NBs.

[0651] The term narrowband is used for reference purposes, and any other term such as sub-band or BW fraction can be used instead to indicate a division unit of the system BW with a smaller BW. Furthermore, NBs can be non-nested or partially nested.

[0652] In DL DCI format or UL DCI format scheduling, each transmission to or from a UE can include a first field indicating an NB and two fields indicating resources within the NB. Also, all of the NBs and PRB allocations within the NB can be indicated by a single field. In order for the gNB to select an NB from the set of NBs to schedule reception or transmission from the UE while improving system spectrum efficiency, the gNB needs to be provided with CSI from the set of NBs to the NB along with CSI from the UE. The UE can provide a CSI report to the NB from the set of NBs by transmitting a CSI report to the NB or by transmitting an SRS to the gNB. The UE can transmit the CSI report on the PUCCH or PUSCH of resources configured by the gNB via higher layer signaling or physical layer (L1) signaling.

[0653] A UE can obtain a CSI report for an NB by measuring the CSI-RS transmitted by the NB. This requires the UE to retune its radio frequency (RF) receiver to the NB to receive the CSI-RS. Because the NB for CSI-RS reception can be different from the NB configured for PDCCH reception, a UE configured to receive a PDCCH requires two retuning operations: one from the NB configured for PDCCH reception to the NB transmitting CSI-RS, and one from the NB transmitting CSI-RS to the NB transmitting PDCCH. RF retuning for the UE receiver requires a period of time during which the UE cannot receive signaling, which can limit the UE's scheduling opportunities and restrict the achievable data rate for the UE. Therefore, it is advantageous to reduce the time during which the UE cannot receive the DL control channel due to retuning operations.

[0654] For SRS transmission from the UE over a BW greater than the maximum SRS transmission BW the UE can support, the UE can transmit the SRS at different NBs with BWs during different time instances. Furthermore, the UE's ability to simultaneously receive from multiple antennas can be greater than the UE's ability to simultaneously transmit from multiple antennas. For TDD systems, it is advantageous to enable SRS transmission from all UE antennas, since the reverse DL BW and UL BW allow SRS transmission from the UE to provide CSI for DL ​​transmission to the UE.

[0655] Therefore, there is a need for a gNB to trigger CSI-RS transmissions at different time instances in different narrowbands.

[0656] There is also another need for the UE to measure CSI-RS at different time instances in different narrowbands.

[0657] There is also another need for a UE to provide CSI reporting for different narrowbands.

[0658] There is yet another need to configure a UE with resources for transmission of a CSI report.There is yet another need to reduce the impact of RF retuning on UE scheduling.

[0659] Finally, there is yet another need to allow a UE to transmit SRS in different narrowbands.

[0660] In one embodiment, a design for triggering CSI-RS transmissions on multiple NBs is considered. CSI-RS transmissions at an NB may be precoded or non-precoded. In the former case, the precoding can be further configured in the UE and can be the same for all NBs (single configuration for all NBs) or different for different NBs (separate configuration per NB). CSI-RS transmissions can include zero-power CSI-RS and non-zero power CSI-RS.

[0661] For a UE to receive CSI-RS at a NB from a configured set of NBs, the UE must retune its RF receiver component to each NB from the set of NBs. Depending on whether the NBs in the set of NBs are in the same or different frequency bands, and depending on the slot duration and the UE retuning capability, the associated RF retuning delay can vary from one or a few symbols to one or more slots. While the UE retunes its receiver RF, the UE cannot receive other signaling from the gNB. Therefore, CSI-RS transmission in a slot must account for the retuning delay while allowing the UE to schedule DL or UL transmission via PDCCH reception at the NB, where the UE is configured to receive the PDCCH.

[0662] If the retuning delay is smaller than the time interval between the last slot symbol in which the UE is configured to receive a PDCCH at the first NB and the first slot symbol of CSI-RS transmission at the second NB, the UE can receive CSI-RS at the second NB after receiving a PDCCH at the first NB when the UE does not receive other signaling such as a PDSCH at the first NB and the first or second slot.

[0663] If the retuning delay is less than the time interval between the last slot symbol for receiving CSI-RS at the second NB and the last slot symbol for receiving PDCCH at the first NB, the UE can retune to the first NB to receive PDCCH after receiving CSI-RS at the second NB. If the UE detects a PDCCH that schedules the UE to receive PDSCH at the first NB and the UE is configured to receive CSI-RS at 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 can drop reception of CSI-RS.

[0664] For a TDD system and a UE with a single duplexer, if the UE is configured to transmit a random access channel, or PUSCH, or a PUCCH similar to carrying a HARQ-ACK at a first NB and the UE is further configured to receive CSI-RS at 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 drop reception of the CSI-RS. For a TDD system and a UE with a single duplexer, if the UE is configured to transmit SRS at a NB and the UE is further configured to receive CSI-RS at a different NB, and the retuning delay is such that the UE is unable to transmit SRS or receive CSI-RS, the UE may prioritize reception of the CSI-RS and drop the SRS transmission. The UE may report the last valid CSI measurement for the NB where the UE dropped CSI-RS reception.

[0665] In one embodiment, CSI-RS transmission at a set of one or more NBs may be semi-permanent or periodic. A UE is configured by a higher layer with a set of NBs and a set of parameters for CSI-RS transmission at each NB from the set of NBs. Each NB in ​​the set of NBs has a respective index determined, for example, in ascending order by system bandwidth. CSI-RS transmission may occur in ascending order of NB index, except for CSI-RS transmission at a NB where the UE is configured to receive a PDCCH, as discussed further below, where CSI-RS transmission may occur first. CSI-RS transmission parameters may be the same for all NBs and may be configured jointly for all NBs, or individually for each NB, except for the slot symbol position for CSI-RS transmission, as discussed further below.

[0666] The CSI-RS transmission parameters are as previously described: CSI-RS resource configuration identity, number of CSI-RS ports, CSI-RS configuration, reference Pc power for each CSI process, pseudo-random sequence generator parameters, n ID The CSI-RS transmission parameters may further include a reference slot and period for CSI-RS transmission at each NB, a number of symbols for CSI-RS transmission in a slot, or a CSI process identity.

[0667] Figure 25 is a diagram illustrating an example CSI-RS transmission 2500 at multiple NBs, where a UE retunes to an NB that the UE has configured for PDCCH reception after receiving a CSI-RS transmission, according to an embodiment of the present invention. The embodiment of CSI-RS transmission 2500 shown in Figure 25 is for illustrative purposes only. One or more of the components shown in Figure 25 may be embodied in specialized circuitry configured to perform the referenced functions, or one or more of the components may be embodied by one or more processors that execute instructions to perform the referenced functions. Other embodiments may be used without departing from the scope of the present invention.

[0668] As shown in Figure 25, the UE is configured with four NBs and a set of NBs including resources for the first NB from the four NBs for PDCCH reception. In the first slot, the UE receives the PDCCH at the first NB 2510 and receives a CSI-RS transmission from the first NB 2515. In the second slot, the UE receives the PDCCH at the first NB 2520, retunes to the second NB to receive a CSI-RS transmission 2525, and then retunes to the first NB to receive the PDCCH in the third slot. In the third slot, the UE receives the PDCCH at the first NB 2530, retunes to the third NB to receive a CSI-RS transmission 2535, and then retunes to the first NB to receive the PDCCH in the fourth slot.

[0669] In the fourth slot, the UE receives the PDCCH at the first NB 2540, retunes to the fourth NB to receive a CSI-RS transmission 2545, and then retunes again to the first NB to receive the PDCCH in the fifth slot. The retuning in slots to NBs that are not the currently active NB at which the UE receives the PDCCH is conditioned on the UE not having a scheduled reception at the currently active NB in ​​the slot. While Figure 25 assumes that CSI-RS transmissions for a UE occur at the same frequency at each NB, different periodicities are also possible, where, for example, the periodicity of CSI-RS transmissions at the first NB is less than other NBs from the set of NBs.

[0670] Instead of the UE retuning to the NB, the UE can be configured for PDCCH reception and the UE can be configured to retune to the NB for the next CSI-RS transmission. For example, if a slot contains 14 symbols, the retuning delay is one symbol, and the last symbol for PDCCH reception in the slot is the third symbol, the UE can receive CSI-RS at all NBs before retuning to the NB where the UE is configured to receive the PDCCH.

[0671] Whether the UE retunes to a new NB to receive CSI-RS transmissions or to an NB configured to receive PDCCH may depend on the time required for the UE to retune between NBs (retuning delay), the number of NBs in the set of NBs using CSI-RS transmissions, or the slot duration, or the maximum duration for PDCCH transmissions.

[0672] Intermediate operations relative to the operations of Figures 25 and 26 are also possible when the UE receives CSI-RS transmissions on a subset of the set of NBs before retuning to the NB configured for PDCCH reception and then retunes to different subsets of the set of NBs for reception of the respective CSI-RS transmissions by retuning the time, slot duration, and maximum duration for transmission of the DL control channel.

[0673] Figure 26 is a diagram illustrating an example CSI-RS transmission 2600 at multiple NBs, with a UE retuning to each NB configured to receive CSI-RS transmission before retuning to an NB configured for PDCCH reception, in accordance with an embodiment of the present invention. The embodiment of CSI-RS transmission 2600 shown in Figure 26 is for illustrative purposes only. One or more of the components shown in Figure 26 may be embodied in specialized circuitry configured to perform the referenced functions, or one or more of the components may be embodied by one or more processors that execute instructions to perform the referenced functions. Other embodiments may be used without departing from the scope of the present invention.

[0674] As shown in Figure 26, a UE is configured with three NBs and a set of NBs including resources in the first NB from the three NBs for PDCCH reception. In the first slot, the UE receives the PDCCH 2610 and the first CSI-RS transmission 2620 at the first NB. The UE then retunes to the second NB to receive the CSI-RS transmission 2630, and then retunes to the third NB to receive the third CSI-RS transmission 2640. After receiving the CSI-RS transmissions at the three NBs, the UE retunes to the first NB to receive the PDCCH in the second slot 2650.

[0675] In another example, CSI-RS transmission at a NB from a set of NBs may be aperiodic and triggered by a DCI format carried on the PDCCH, which may be a DL DCI format that schedules PDSCH transmission to a UE or a separate DCI format with content for one or more UEs.

[0676] When the DCI format for triggering CSI-RS transmission at one or more NBs from a set of NBs is a DL DCI format for scheduling PDSCH transmission to a UE in one or more slots, the DL DCI format may include a field indicating one or more NBs from the set of NBs for CSI-RS transmission. When the NB for PDSCH transmission is also an NB with triggered CSI-RS transmission due to the DL DCI format scheduling PDSCH transmission to a UE, in order to be able to receive the PDSCH, the first CSI-RS transmission may occur at the NB at which the UE is configured to receive the PDCCH, and subsequent CSI-RS transmissions are at the remaining NBs in ascending (or descending) order of NB index.

[0677] When the NB from which the UE is configured to receive the PDCCH is not the NB with the triggered CSI-RS transmission, the UE may receive the PDSCH in one or more slots and then retune to an NB with a triggered CSI-RS transmission one or more slots later. The CSI-RS transmission at the NB may be by ascending NB index, including the NB with the scheduled DL data channel transmission when the CSI-RS transmission is triggered. The retuning delay allows the UE to receive the PDCCH at the NB in ​​the next slot before retuning, and when the UE detects another DL DCI format in one or more next slots that schedules a PDSCH transmission to the UE at the first NB, the UE can ignore triggered CSI-RS transmissions at NBs other than the first NB in ​​one or more next slots.

[0678] A field in the DL DCI format for triggering CSI-RS transmission at one or more NBs among a set of NBs for which the UE is configured may include an indication of the NB. For example, a field having two binary elements (bits) may use a value of "00" to indicate no CSI-RS transmission, or may use values ​​of "01," "10," and "11" to indicate CSI-RS transmission at the first, second, or third configured subset of the set of NBs, respectively. The parameters for CSI-RS transmission at each NB may be the same or different. As described above, separate fields may be used to indicate the NBs for CSI-RS reception and to trigger CSI-RS reception and to indicate the CSI-RS configuration.

[0679] For example, the CSI-RS resource configuration identity, the number of CSI-RS parameters, the CSI-RS configuration, the reference Pc power for each CSI processor, the pseudo-random sequence generator parameters, the nID, the CDM type parameters, the number of symbols in a slot, or the CSI process identity may be the same for all NBs. The location of the slot symbols for CSI-RS transmission in each NB may be the same or different. For example, when CSI-RS transmissions are in different slots in different NBs, the respective slot symbols may be the same. For example, when CSI-RS transmissions are in the same slot in at least some NBs, the respective slot symbols may be different, and the respective offsets in the number of symbols for consecutive CSI-RS transmissions may be determined from the retuning delay for the UE having the associated triggering CSI-RS transmission, or may be signaled by the gNB via UE-common upper layer signaling such as system information or UE-specific upper layer signaling.

[0680] A DL DCI format that schedules DL data channel transmission to the UE and triggers reception by the UE of CSI-RS transmissions at one or more NBs from a set of NBs may also trigger PUCCH transmissions from the UE carrying CSI reports for one or more NBs. Resources for PUCCH transmissions may be explicitly indicated in the DL DCI format or may be configured in the UE by higher layer signaling.

[0681] In a first example, the DL DCI format may include a PUCCH resource allocation field for CSI reporting. A UE may be configured with four PUCCH resources by a higher layer, and the PUCCH resource allocation field for CSI reporting may include two bits indicating one of the four configured resources.

[0682] In a second example, the DL DCI format may include a PUCCH resource allocation field for HARQ-ACK reporting related to the UE's reception result for the 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 HARQ-ACK reporting may include two bits indicating one of the four configured resources. Then, the PUCCH resource for CSI reporting may be derived from the PUCCH resource for HARQ-ACK reporting. The UE may further be configured with four PUCCH resources for CSI reporting by a higher layer. For example, if a third PUCCH resource is indicated for HARQ-ACK reporting, the UE may further use the third PUCCH resource for CSI reporting. Therefore, the PUCCH resources for HARQ-ACK reporting and CSI reporting are different but jointly indicated.

[0683] The same approach can be applied to the transmission timing of the HARQ-ACK report and the CSI report. For example, to avoid simultaneous transmission from the UE of a first PUCCH carrying an HARQ-ACK report and a second PUCCH carrying a CSI report, after the slot in which the UE transmits the CSI report, the UE may transmit the CSI report in the next slot or a predetermined slot. The UE may also be configured to transmit consecutive PUCCHs in different symbols of the same slot. The DL DCI format may further include a TPC command for the UE to adjust the PUCCH transmit power for the HARQ-ACK report. Assuming the same closed-loop power control process for PUCCH transmission, the UE also applies the TPC command to adjust the PUCCH transmit power for the CSI report.

[0684] When the DCI format that triggers CSI-RS transmission within an NB from the set of NBs for a UE 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 size of the DCI format decoded by the UE for other purposes, such as obtaining TPC commands. The CRC of the DCI format may be scrambled with an RNTI specific to triggering CSI-RS transmission, such as CSI-RS-RNTI. For simplicity, a DCI format with CSI-RS-RNTI is referred to as DCI format T. Using DCI format T, a gNB can trigger CSI-RS transmission for each UE in a group of UEs configured with the same CSI-RS-RNTI at a different NB from the set of configured NBs, and possibly at a different cell.

[0685] The UE may configure the location within DCI format T at which the UE can obtain the CSI-RS trigger field, which indicates CSI-RS transmission at a subset of NBs from the configured set of NBs via the parameter Index-CSI-RS. For example, as described for the DL DCI format, the CSI-RS trigger field may have two bits, or may have more bits than the DL DCI format for increased granularity, where a value of "00" may indicate no CSI-RS transmission and the remaining values ​​may each indicate CSI-RS transmission from the configured subset (including all NBs in the set of NBs).

[0686] For example, increased granularity can be used when there are multiple NBs in the set of NBs or when a UE can trigger CSI-RS transmission from multiple NBs and multiple cells or multiple slot sets. Alternatively, DCI format T can include separate CSI-RS trigger fields for sets of NBs on different cells for the same UE. Also, when the CSI-RS trigger field triggers CSI-RS transmission, it can do so for all NBs in the set of NBs. Then, the CSI-RS trigger field can include a single bit for each UE in a cell, where a value of "0" indicates no CSI-RS triggering and a value of "1" indicates CSI-RS triggering at all NBs in the set of NBs.

[0687] DCI format T may further include a field indicating a PUCCH resource for transmission of a PUCCH carrying a CSI report from a UE in response to a field carrying a TPC command for PUCCH transmission and measurements related to NB-triggered CSI-RS transmission from a set of configured NBs. The PUCCH resource field may be an index to a PUCCH resource from a set of configured PUCCH resources.

[0688] For example, when the PUCCH resource field includes 2 bits, the PUCCH resource field can indicate one of four configured PUCCH resources. The position of the PUCCH resource field or the position of the TPC command field can be linked to the configured position of the CSI-RS trigger field, for example, the PUCCH resource field can be in the next position and the TPC command field can be in the next position or later (or vice versa or in the previous position).

[0689] DCI format T may further indicate a single PUCCH resource for transmitting a PUCCH carrying a CSI report related to the first position, where the CSI-RS trigger field of DCI format T does not have a “00” value, and PUCCH resources for PUCCH transmissions carrying other CSI reports may be determined for the indicated PUCCH resource.

[0690] For example, a UE having a first position in DCI format T for a CSI-RS transmission trigger field with a value different from "00" can use the indicated first PUCCH resource to transmit a PUCCH carrying a CSI report, a UE having a second position in DCI format T for a CSI-RS transmission trigger field with a value different from "00" can use the second PUCCH resource after the first PUCCH resource, a UE having a third position in DCI format T for a CSI-RS transmission trigger field with a value different from "00" can use the second PUCCH resource and then the third PUCCH resource, and so on.

[0691] Therefore, PUCCH resource n PUCCH If displayed in DCI format T, n is not "00" CSI-RS The UE with the nth CSI-RS transmission trigger value transmits PUCCH resource n PUCCH +n CSI-RS-1 or by assigning index "0" (instead of index "1") to the first CSI-RS transmission trigger value that is not "00". CSI-RS The UE with the th CSI-RS transmission trigger value is PUCCH resource n PUCCH +n CSI-RS The CSI report from the UE can be a CSI report for each NB combined with the triggered CSI-RS transmission, or the UE can select a predetermined number of NBs from the NBs with triggered CSI-RS transmission to provide the respective CSI reports.

[0692] The DL DCI format or DCI format T may further include a TPC command field for the UE to adjust the power for transmitting the PUCCH carrying the CSI report. The TPC command field may be located next to the CSI-RS transmission trigger field (before or after) or may be located in a different configuration position for each UE. A UE may be configured with one or more CSI-RS-RNTIs, where the content of DCI format T is interpreted by the CSI-RS-RNTIs. For example, a first CSI-RS-RNTI may correspond to a first set of NBs or a first group of cells, while a second CSI-RS-RNTI may correspond to a second set of NBs or a second group of cells.

[0693] Figure 27 is a drawing illustrating example content 2700 of a DCI format having a CRC scrambled by a CSI-RS-RNTI to trigger CSI-RS transmission at a subset of NBs from a set of NBs for one or more UEs, according to an embodiment of the present invention. The embodiment of DCI format content 2700 shown in Figure 27 is for illustrative purposes only. One or more of the components shown in Figure 27 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied 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 invention.

[0694] As shown in Figure 27, the gNB configures the UE with a set of NBs, a CSI-RS-RNTI for scrambling the CRC of the DCI format, and the position of the DCI format for the CSI-RS trigger field for triggering CSI-RS transmission at a subset of NBs from the set of NBs 2710. The set of NBs is configured individually for each UE for different UEs with the same configured CSI-RS-RNTI. The gNB determines each subset of NBs for triggering CSI-RS transmission 2720 and the UEs with the same CSI-RS-RNTI from the above group of UEs. The gNB configures the value of the CSI-RS trigger field depending on whether the gNB triggers CSI-RS transmission for the UE 2730 and the subset of NBs with triggered CSI-RS transmission when CSI-RS transmission is triggered.

[0695] The CSI-RS trigger field can contain two bits where a value of "00" does not trigger any CSI-RS transmission for the UE, values ​​of "01," "10," or "11" trigger CSI-RS transmission in a first, second, or third subset, where the set of NBs can include all NBs, or CSI-RS transmission with a first, second, or third configuration at the NBs indicated by the respective fields in the DCI format. The gNB transmits a DCI format with a CRC scrambled by the CSI-RS-RNTI (2740). The UE receives from the gNB a configuration for the set of NBs, a configuration for the CSI-RS-RNTI that scrambles the CRC of the DCI format, and a configuration for the location within the DCI format of the CSI-RS trigger field that can trigger CSI-RS transmission in the subset of NBs (2750).

[0696] The UE detects 2760 a DCI format having a CRC scrambled by the CSI-RS-RNTI. The UE acquires 2770 a value for the CSI-RS trigger field. If the value of the CSI-RS trigger field is "00," the UE does not receive CSI-RS. If the value of the CSI-RS trigger field is "01," "10," or "11," the UE receives CSI-RS transmissions on the first, second, or third subset of NBs, respectively, or receives CSI-RS according to the first, second, or third configuration (2780).

[0697] 28 is a diagram illustrating example content 2800 of a DCI format having a CRC scrambled by a CSI-RS-RNTI that triggers CSI-RS transmission at a subset of NBs among a set of NBs for one or more UEs and provides PUCCH resources and TPC commands for CSI report transmission, according to an embodiment of the present invention. The embodiment of DCI format content 2800 shown in FIG. 28 is for illustrative purposes only. One or more of the components shown in FIG. 28 may be embodied in specialized circuitry configured to perform the referenced functions, or one or more of the components may be embodied by one or more processors that execute instructions to perform the referenced functions. Other embodiments may be used without departing from the scope of the present invention.

[0698] As shown in Figure 28, the gNB configures the UE with a set of NBs, a CSI-RS-RNTI for scrambling the CRC of the DCI format, the position of the DCI format relative to the CSI-RS trigger field for triggering CSI-RS transmission at a subset of NBs from the set of NBs, and a TPC command for adjusting the power of the PUCCH transmission containing the CSI report 2810. The set of NBs can be different for different UEs. The gNB determines a group of one or more UEs configured with the same CSI-RS-RNTI and UEs from each subset of NBs for triggering CSI-RS transmission 2820.

[0699] Depending on whether the gNB triggers CSI-RS transmission to the UE and the subset of NBs that have triggered CSI-RS transmission when CSI-RS transmission is triggered, the gNB sets the value of the CSI-RS trigger field so that the UE can process TPC commands in DCI format even when the UE does not trigger CSI-RS transmission and does not transmit a PUCCH carrying a CSI report 2830.

[0700] The CSI-RS trigger field may include two bits where a "00" value does not trigger any CSI-RS transmission to the UE, and "01," "10," or "11" values ​​trigger CSI-RS transmission in a subset of the first, second, and third NBs, respectively, which may include all NBs in the set of NRs. Additionally or alternatively, the CSI-RS trigger field may indicate a CSI-RS configuration. The TPC command may include two bits with mapping values ​​of "00," "01," "10," or "11" for power adjustments of, for example, -3 dB, -1 dB, 1 dB, and 3 dB. The gNB transmits (2840) a DCI format with a CRC scrambled by the CSI-RS-RNTI.

[0701] The UE receives from the gNB a set of NBs, a CSI-RS-RNTI that scrambles the CRC of the DCI format, and a configuration for the location of the DCI format in the CSI-RS trigger field that can trigger CSI-RS transmission at a subset of NBs, and a TPC field for adjusting the power of the PUCCH that carries the CSI report (2850). The UE detects the DCI format in the CRC scrambled by the CSI-RS-RNTI (2860). The UE obtains values ​​for the CSI-RS trigger field and the TPC command field (2870).

[0702] If the value of the CSI-RS trigger field is "00", the UE does not receive CSI-RS. If the value of the CSI-RS trigger field is "01", "10", or "11", the UE receives CSI-RS transmissions on a subset of the first, second, and third NBs, or receives CSI-RS transmissions according to the first, second, or third CSI-RS configuration. The DCI format further specifies the number of PUCCH resources n used by a UE with a first CSI-RS trigger value other than "00" in the DCI format to transmit a PUCCH carrying a CSI report. PUCCH , and n used by UEs with a CSI-RS trigger other than "00" in the DCI format CSI-RS+1, PUCCH resource n used to transmit the PUCCH carrying the CSI report with power adjusted based on the TPC command field value PUCCH +n CSI-RS It includes a PUCCH resource field indicating:

[0703] 29 is a diagram illustrating an example PUCCH resource determination 2900 in which a UE transmits a PUCCH carrying a CSI report based on a PUCCH resource indicated in a DCI format that triggers CSI-RS transmission, according to an embodiment of the present invention. The embodiment of PUCCH resource determination 2900 illustrated in FIG. 29 is for illustrative purposes only. One or more of the components illustrated in FIG. 29 may be embodied in specialized circuitry configured to perform the referenced functions, or one or more of the components may be embodied by one or more processors that execute instructions to perform the referenced functions. Other embodiments may be used without departing from the scope of the present invention.

[0704] Referring to FIG. 29, a fourth UE, UE#3 (2910), having a PUCCH transmission carrying a CSI report in response to detecting a DCI format having a CRC scrambled with the CSI-RS-RNTI includes an RS trigger field for the UE having a value other than “00”, and a reference PUCCH resource n PUCCH is determined based on the presence of two CSI-RS trigger fields having values ​​other than "00" in positions before the UE's position (2920 and 2930). Based on the determination of the CSI-RS trigger fields having values ​​other than "00" in positions before the CSI-RS trigger field for UE #3 in the DCI format, UE #3 selects PUCCH resource n for PUCCH transmission carrying a CSI report in response to measurements from CSI-RS transmissions having CSI RS trigger values ​​for UE #3. PUCCH Decide +2.

[0705] gNB is composed of N NB ≧M NB NB set to M NBThe UE can be configured to report CSI to the NB or NB The value of can be defined in the system operation. NB From the NB set NB NB can be selected. For example, each N NB N within NB NB From the measured CQI values ​​of M NB ≦N NB Select the maximum CQI value and report the respective M NB NB can be shown.

[0706] The UE may be further configured with a gNB that includes a CSI report for the NB, where the UE is configured to receive a PDCCH, or the inclusion of the CSI report may be specified in system operation. The set of configured NBs may also exclude NBs for which the UE is configured to receive a PDCCH and for which the UE can provide individual CSI reports. For example, the UE may provide CSI reports with a larger periodicity for an NB, where the UE is configured to receive a PDCCH than other NBs.

[0707] UE is M NB >1 When reporting CSI to the NB, the UE shall report the maximum CQI value CQI max (j0) and the respective NB index J0 can be reported,

[0708]

number

[0709] (where:

[0710]

number

[0711] ) differential CQI offset value DCQI(j) can be reported. For example, for a DCQI(j) value expressed in 2 bits, the mapping from the 2-bit differential CQI value to the offset value may be the same as in Table 2. N NB M with configured NB and CSI reports NB In the case of NB, for example, M is used with the same combination index as in the LTE specification. NB An index for NB can be obtained. M NB The number of bits indicating the position of NB is

[0712]

number

[0713] The index of the NB may be preferentially arranged in the CSI report, and each CSI value or pair of NB index and CSI report may be arranged, for example, starting from the NB with the largest CQI value and subsequently to other NBs in an ascending index order.

[0714] [Table 2]

[0715] The NBs at which the UE is configured to receive the PDCCH may hop across slots within the set of configured NBs. For example, the NBs at which the UE is configured to receive the PDCCH may cycle through the NBs in the set of configured NBs across slots in ascending order of NB index, or may have a hopping pattern that maximizes frequency diversity, such as the SRS transmission BW hopping pattern as described in the LTE specification.

[0716] This allows the UE to receive PDCCH and CSI-RS transmissions from the same NB while reducing the impact of delays associated with retuning from the first NB, and the UE is configured to receive PDCCH and CSI-RS transmissions from the second NB, and then receive PDCCH from the first NB, which can be particularly useful when the retuning time between different NBs is relatively long and the UE is unable to receive CSI-RS transmissions for all individual NBs in a single slot.

[0717] If the UE is not configured to receive PDSCH or other DL signaling in the slot, the UE may use the remaining long duration in the slot after one or more additional symbols for processing delay to determine the symbols for decoding the PDSCH and potential scheduling of the PDSCH and retune to a different NB for reception of the PDCCH and possibly CSI-RS.

[0718] If a UE is configured to receive a PDSCH or other DL signaling in a slot and the UE does not have enough time to retune to the next NB according to the NB hopping pattern before the beginning of the next slot, as discussed below, the UE can skip retuning to the next NB and later reconfigure the NB hopping pattern in the slot, or the UE can retune to the next NB but miss reception of the PDCCH due to the retuning. To mitigate the impact of not being able to receive the PDCCH in a slot, the gNB can schedule multi-slot transmission of the PDSCH for the UE, where the PDSCH is transmitted in different NBs in different slots according to the NB hopping pattern. Thereafter, if the UE is able to retune within a time not greater than the configured duration for PDCCH transmission in the slot, the UE can receive the PDSCH after retuning to a different NB in ​​a different slot.

[0719] Figure 30 is a diagram illustrating a hopping pattern 3000 of a NB configured for a UE to receive a PDCCH according to an embodiment of the present invention. The embodiment of the hopping pattern 3000 illustrated in Figure 30 is for illustrative purposes only. One or more of the components illustrated in Figure 30 may be embodied in specialized circuitry configured to perform the functions described, or one or more of the components may be embodied by one or more processors that execute instructions to perform the functions described. Other embodiments may be used without departing from the scope of the present invention.

[0720] As shown in Figure 30, the UE is configured with a set of NBs including four NBs, i.e., NB0, NB1, NB2, and NB3, and a resource for the first symbol of the NB for receiving the PDCCH (3005). In the first slot, the UE receives the PDCCH in NB1 (3010) and can also receive CSI-RS transmissions in slot symbols having a first time distance to the edge of the first slot that is greater than the UE retuning period. The UE is configured not to receive any DL signaling for a time period equal to the retuning period relative to the edge of the first slot.

[0721] During the first time distance, the UE may retune to NB3 for reception of the PDCCH in the second slot. In the second slot, the UE may receive the PDCCH at NB3 3020 and may also receive CSI-RS transmissions in slot symbols having a second time distance to the end of the second slot that is greater than the UE retuning period. The UE is configured not to receive other DL signaling during a time period identical to the retuning period relative to the end of the second slot. During the second time distance, the UE may retune to NB0 for reception of the PDCCH in the third slot. In the third slot, the UE may receive the PDCCH at NB0 3030 and may also receive CSI-RS transmissions in slot symbols having a third time distance to the end of the third slot that is greater than the UE retuning period.

[0722] The UE is configured not to receive any DL signaling for a time period equal to the retuning period relative to the edge of the third slot. During the third time distance, the UE may retune to NB2 to receive a PDCCH in the fourth slot. During the fourth slot, the UE may receive a PDCCH at NB2 3040 and also receive a CSI-RS transmission in a slot symbol having a fourth time distance to the end of the fourth slot that is greater than the UE retuning period. The UE is configured not to receive any DL signaling for a time period equal to the retuning period relative to the edge of the fourth slot. During the fourth time distance, the UE may retune to NB1 to receive a PDCCH in the fifth slot. During the fifth slot, the UE may receive a PDCCH at NB1 3050 and also receive a CSI-RS transmission in a slot symbol that is a fifth time distance to the end of the fifth slot that is not greater than the UE retuning period. While the UE is receiving DL signaling in slot 5, it does not have enough time to retune to NB3 for reception of the PDCCH in slot 6. There are two approaches to UE operation.

[0723] In the first approach, the UE retunes to NB3 in slot 6 for possible reception of CSI-RS transmission, and the UE cannot receive PDCCH 3060. In the second approach, the UE remains tuned to NB1 in slot 6 to receive PDCCH in slot 6. The first approach avoids an error case that can occur, for example, when the UE cannot detect the DL DCI format in slot 5 that schedules DL data channel reception in slot 5 and retunes to NB3 in slot 6.

[0724] The second approach relies on the gNB to handle potential error cases. Both approaches allow for persistent scheduling of the UE. The first approach relies on the UE retuning within the time period for transmission of the DL control channel in a slot by applying multi-slot scheduling, while the second approach relies on the UE applying single-slot or multi-slot scheduling. The UE resumes the NB hopping pattern in the seventh slot 3070. UE behavior can be specified by system operation or configured by the UE or the gNB using one of the two approaches.

[0725] SRS transmission through multiple NBs can follow similar principles to CSI-RS transmission through multiple NBs, and the following description is summarized for completeness. SRS transmission at an NB can be precoded or not. In the former case, precoding can be further configured for the UE and can be the same for all NBs (single configuration) or different for different NBs (different configuration). SRS transmission can include zero-power SRS and non-zero-power SRS.

[0726] For a UE to transmit an SRS on an NB from a set of NBs, the UE must retune its RF transmission components to each NB in ​​the set of NBs. If the UE is configured to transmit UL signaling, such as a random access channel or PUSCH or PUCCH, on an NB and the UE is configured to transmit an SRS on a different NB, the UE may drop the SRS transmission because the UE cannot transmit the UL signaling and SRS due to the RF retuning delay.

[0727] For a TDD system and a UE with a single duplexer, if the retuning delay is less than the time interval between the last slot symbol in which the UE is configured to receive a PDCCH at a first NB and the first slot symbol in which the UE transmits an SRS at a second NB, the UE can transmit an SRS at a second NB after receiving a PDCCH at a first NB. If the retuning delay is less than the time interval between the last slot symbol in which the UE is configured to transmit an SRS at a second NB and the first slot symbol in which the UE is configured to receive a PDCCH at a first NB, the UE can receive a PDCCH after transmitting an SRS at a second NB by retuning to the first NB.

[0728] If the UE detects a DCI format in the PDCCH that schedules the UE to receive a PDSCH or PUSCH at an NB, and the UE is configured to transmit an SRS at a different NB, the UE may drop the SRS transmission. For a TDD system and a UE with a single duplexer, the UE may drop the SRS transmission if the retuning delay is greater than the time between the last symbol of the PDSCH reception or PUSCH transmission and the first symbol of the SRS transmission (or vice versa).

[0729] In one embodiment, SRS transmission in a set of one or more NBs may be semi-permanent or periodic. The UE is configured by a higher layer of the NB and parameters for SRS transmission at each NB of the set NB. The SRS transmission parameters may be identical for all NBs except for the slot symbol position for SRS transmission, as discussed further below, and may be configured jointly for all NBs, or may differ in part for each NB and be configured individually for each NB. The SRS transmission parameters may include one or more of the number of combs, the number of slot symbols (duration) for SRS transmission at each NB, the transmit comb, the starting PRB, the period, the BW, a cyclic shift, precoding, or the number of antenna ports.

[0730] In another example, SRS transmissions within a set of NBs may be aperiodic and triggered by a DCI format carried on a PDCCH, which may be a DL DCI format for scheduling PDSCH transmissions to a UE, a UL DCI format for scheduling PUSCH transmissions from a UE, or a separate DCI format having content for triggering SRS transmissions from one or more UEs.

[0731] When the DCI format for triggering SRS transmission at one or more NBs of a set of NBs is a UL DCI format or a DL DCI format, the DCI format may include a field indicating an NB from the set of NBs configured for each SRS transmission from the UE, or may include a field indicating an SRS transmission configuration in a manner similar to that described for triggering CSI-RS transmission. In a UL DCI format for scheduling a PUSCH transmission from a UE to trigger SRS transmission at NBs from the UE, if the NB for PUSCH transmission is also a NB that has a triggered SRS transmission, the UE can transmit a PUSCH by predicting that the first SRS transmission occurs at the NB for PUSCH transmission and that subsequent SRS transmissions will be from the remaining NBs in ascending (or descending) order of NB index.

[0732] If the NB transmitting the PUSCH is not the NB with the triggered SRS transmission, the UE may transmit the PUSCH in one or more slots and subsequently retune to the NB with the triggered SRS transmission one or more slots later. Furthermore, the SRS transmission at the NB may be according to an ascending NB index that includes the NB with the PUSCH transmission when the SRS transmission is triggered.

[0733] A field in the UL DCI format that triggers SRS transmission at one or more NBs of the set of NBs to which the UE is configured can include an indication of the NBs. For example, a field with 2 bits can indicate no SRS transmission using a value of "00" and indicate SRS transmission at a subset of the first, second, or third NBs configured from the set of NBs using values ​​of "01," "1," and "11," or indicate a first, second, or third configuration for SRS transmission. The parameters for SRS transmission at each NB can be the same or different.

[0734] The slot symbol locations for SRS transmissions in each NB can be the same or different. For example, if SRS transmissions are in different slots in different NBs, the respective slot symbols can be the same. For example, if SRS transmissions in at least some NBs are in the same slot, the respective slot symbols are different, and the respective offsets in the multiple symbols for consecutive SRS transmissions can be determined from the retuning delay for the UE having the associated triggered SRS transmission, or can be based on UE-common upper layer signaling or UE-specific upper layer signaling, such as system information signaled by the gNB.

[0735] The SRS transmission at the NB can also be via multiple slot symbols, where, for example, the SRS transmission is from a first antenna port in a first symbol and a second antenna port in a second symbol, or from different antenna ports in different symbols, such as from the same antenna port, thereby allowing the gNB to obtain a more accurate estimate of the channel medium from the SRS transmission.

[0736] If the DCI format that triggers SRS transmission at an NB among the set of NBs for the UE is not the UL DCI format or the 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 DCI format decoded for other purposes such as obtaining a TPC command. The CRC of the DCI format may be scrambled with an RNTI specific to the trigger of SRS transmission, such as SRS-RNTI. For simplicity, the DCI format with SRS-RNTI is referred to as DCI format X.

[0737] Using DCI format X, a gNB can trigger SRS transmission for each UE in a group of UEs configured with the same SRS-RNTI at different NBs among the set of configured NBs, and possibly in different cells. The UE can be configured at a location within DCI format X via an index parameter, Index-SRS, from which it can obtain an SRS trigger field indicating SRS transmission at a subset of NBs among the set of configured NBs, or indicating an SRS transmission configuration. The SRS trigger field can operate as described for the UL DCI format or DL ​​DCI format, or can have increased granularity similar to the CSI-RS trigger.

[0738] Furthermore, if the SRS trigger field triggers SRS transmission, it may do so for all NBs in the NB set. The SRS trigger field may also include a single bit for each UE per cell, where a value of "0" indicates no SRS trigger and a value of "1" indicates SRS trigger at all NBs in the set of NBs. The DL DCI format or DCI format X may also include a TPC field for the UE to adjust SRS transmit power. The TPC command field may follow the SRS transmission trigger field or may be in a different location configured for each UE. The UE may be configured with more than one SRS-RNTI so that the contents of DCI format X are interpreted by the SRS-RNTI. For example, a first SRS-RNTI may correspond to a first set of NBs or a first group of cells, and a second SRS-RNTI may correspond to a second set of NBs or a second group of cells.

[0739] The functions of DCI format T and DCI format X can be combined using DCI format Y, which may have the same size as the UL DCI format or the DL DCI format decoded by the UE, or may be the same size as the DCI format decoded by the UE for purposes other than obtaining TPC commands. The UE can be configured with one or more respective positions for one or more cells for the RS-RNTI and CSI-RS trigger fields for triggering both CSI-RS transmission and SRS transmission, followed by the SRS trigger field, and the subsequent TPC command field (or any other sequence for these three fields), where the cell for CSI-RS reception can be different from the cell for SRS transmission, and the link between the cell index and the trigger position can be configured individually. DCI format Y can also include a reference PUCCH resource for PUCCH transmission in response to a CSI-RS trigger value other than "00," as described in FIG. 29.

[0740] Although the present disclosure has been described in exemplary embodiments, various changes and modifications may be suggested to those skilled in the art, and the present disclosure is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0741] Nothing in this application should be read as indicating any particular element, step, or function as essential, which must be included in the claims. The scope of the invention is defined solely by the claims. Also, no claim herein is intended to invoke 35 U.S.C. § 112(f) unless the precise words "means for" are followed by a participial construction. [Explanation of symbols]

[0742] 100 Wireless Networks 101-103 eNB 111-116 UE 120, 125 coverage area 130 Network 205a-205n antenna 210a-210n RF transceiver 215 Transmit (TX) processing circuit 220 Receive (RX) processing circuit 225 Controller / Processor 230 Memory 235 Backhaul or Network Interface 305 Antenna 310 Radio Frequency (RF) Transceiver 315 TX processing circuit 320 microphone 325 Receive (RX) processing circuit 330 speakers 340 processor 345 I / O interface 350 Touchscreen 355 Display 360 Memory 361 OS 362 Applications

Claims

1. 1. A method performed by a user equipment (UE) in a communication system, comprising: receiving information about a common search space from a base station; receiving information about a UE-specific search space from the base station; determining a first number of physical downlink control channel (PDCCH) candidates for the common search space within a slot based on the information about the common search space; determining a second number of PDCCH candidates for the UE-specific search space within the slot; monitoring the PDCCH candidates for the common search space in the slot and the PDCCH candidates for the UE-specific search space in the slot; The method of claim 1, wherein the second number is greater in slots in which the UE does not monitor the common search space than in slots in which the UE monitors the common search space.

2. the information about the common search space includes periodicity information about the common search space; The method of claim 1 , wherein the information about the UE-specific search space includes periodicity information about the UE-specific search space.

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

4. 1. A method performed by a base station in a communications system, comprising: transmitting information about a common search space to a user equipment (UE); transmitting information about a UE-specific search space to the UE; determining a first number of physical downlink control channel (PDCCH) candidates for the common search space within a slot based on the information about the common search space; determining a second number of PDCCH candidates for the UE-specific search space within the slot; transmitting downlink control information (DCI) to the UE based on the PDCCH candidates for the UE-specific search space in the slot and the PDCCH candidates for the common search space in the slot; The method of claim 1, wherein the second number is greater in slots in which the UE does not monitor the common search space than in slots in which the UE monitors the common search space.

5. the information about the common search space includes periodicity information about the common search space; The method of claim 4 , wherein the information about the UE-specific search space includes periodicity information about the UE-specific search space.

6. 5. The method of claim 4, wherein a control channel element (CCE)-to-resource element group (REG) mapping for a control resource set and a size of a REG bundle associated with the interleaved CCE-to-REG mapping for the control resource set are transmitted to a terminal.

7. In a UE (user equipment) in a communication system, a transmitter / receiver; a control unit connected to the transceiver unit, The control unit receiving information about a common search space from a base station; receiving information about a UE-specific search space from the base station; determining a first number of physical downlink control channel (PDCCH) candidates for the common search space within a slot based on the information about the common search space; determining a second number of PDCCH candidates for the UE-specific search space within the slot; monitoring the PDCCH candidates for the common search space within the slot and the PDCCH candidates for the UE-specific search space within the slot; The UE, wherein the second number is greater in slots in which the UE does not monitor the common search space than in slots in which the UE monitors the common search space.

8. the information about the common search space includes periodicity information about the common search space; The UE of claim 7 , wherein the information about the UE-specific search space includes periodicity information about the UE-specific search space.

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

10. In a base station in a communication system, a transmitter / receiver; a control unit connected to the transceiver unit, The control unit transmitting information about the common search space to a user equipment (UE); transmitting information about a UE-specific search space to the UE; determining a first number of physical downlink control channel (PDCCH) candidates for the common search space within a slot based on the information about the common search space; determining a second number of PDCCH candidates for the UE-specific search space within the slot; transmitting downlink control information (DCI) to the UE based on the PDCCH candidates for the UE-specific search space in the slot and the PDCCH candidates for the common search space in the slot; The base station, wherein the second number is greater in slots in which the UE does not monitor the common search space than in slots in which the UE monitors the common search space.

11. the information about the common search space includes periodicity information about the common search space; The base station of claim 10, wherein the information about the UE-specific search space includes periodicity information about the UE-specific search space.

12. 11. The base station of claim 10, wherein a control channel element (CCE)-to-resource element group (REG) mapping for a control resource set and a size of a REG bundle associated with the interleaved CCE-to-REG mapping for the control resource set are transmitted to a terminal.

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