WO2022131713A1 - Codebook for distributed mimo transmission - Google Patents

Codebook for distributed mimo transmission Download PDF

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Publication number
WO2022131713A1
WO2022131713A1 PCT/KR2021/018843 KR2021018843W WO2022131713A1 WO 2022131713 A1 WO2022131713 A1 WO 2022131713A1 KR 2021018843 W KR2021018843 W KR 2021018843W WO 2022131713 A1 WO2022131713 A1 WO 2022131713A1
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WO
WIPO (PCT)
Prior art keywords
rrh
csi
information
strongest
rrhs
Prior art date
Application number
PCT/KR2021/018843
Other languages
French (fr)
Inventor
Md Saifur RAHMAN
Eko Nugroho Onggosanusi
Original Assignee
Samsung Electronics Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US17/542,298 external-priority patent/US20220190897A1/en
Application filed by Samsung Electronics Co., Ltd. filed Critical Samsung Electronics Co., Ltd.
Priority to KR1020237016796A priority Critical patent/KR20230117109A/en
Priority to CN202180083973.4A priority patent/CN116615870A/en
Publication of WO2022131713A1 publication Critical patent/WO2022131713A1/en

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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621Feedback content
    • H04B7/0626Channel coefficients, e.g. channel state information [CSI]
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0602Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using antenna switching
    • H04B7/0608Antenna selection according to transmission parameters
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022Site diversity; Macro-diversity
    • H04B7/024Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413MIMO systems
    • H04B7/0456Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H04B7/0478Special codebook structures directed to feedback optimisation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621Feedback content
    • H04B7/063Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0636Feedback format
    • H04B7/0639Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0686Hybrid systems, i.e. switching and simultaneous transmission
    • H04B7/0691Hybrid systems, i.e. switching and simultaneous transmission using subgroups of transmit antennas
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048Allocation of pilot signals, i.e. of signals known to the receiver
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management
    • H04W72/20Control channels or signalling for resource management
    • H04W72/21Control channels or signalling for resource management in the uplink direction of a wireless link, i.e. towards the network

Definitions

  • the present disclosure relates generally to wireless communication systems and more specifically to CSI reporting based on a codebook for distributed MIMO transmission.
  • the 5G or pre-5G communication system is also called a 'Beyond 4G Network' or a 'Post LTE System'.
  • the 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60GHz bands, so as to accomplish higher data rates.
  • mmWave e.g., 60GHz bands
  • MIMO massive multiple-input multiple-output
  • FD-MIMO Full Dimensional MIMO
  • array antenna an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
  • RANs Cloud Radio Access Networks
  • D2D device-to-device
  • CoMP Coordinated Multi-Points
  • FQAM Hybrid FSK and QAM Modulation
  • SWSC sliding window superposition coding
  • ACM advanced coding modulation
  • FBMC filter bank multi carrier
  • NOMA non-orthogonal multiple access
  • SCMA sparse code multiple access
  • the Internet which is a human centered connectivity network where humans generate and consume information
  • IoT Internet of Things
  • IoE Internet of Everything
  • sensing technology “wired/wireless communication and network infrastructure”, “service interface technology”, and “Security technology”
  • M2M Machine-to-Machine
  • MTC Machine Type Communication
  • IoT Internet technology services
  • IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing Information Technology (IT) and various industrial applications.
  • IT Information Technology
  • 5G communication systems to IoT networks.
  • technologies such as a sensor network, Machine Type Communication (MTC), and Machine-to-Machine (M2M) communication may be implemented by beamforming, MIMO, and array antennas.
  • MTC Machine Type Communication
  • M2M Machine-to-Machine
  • Application of a cloud Radio Access Network (RAN) as the above-described Big Data processing technology may also be considered to be as an example of convergence between the 5G technology and the IoT technology.
  • RAN Radio Access Network
  • the gNB may transmit a reference signal, e.g., CSI-RS, to the UE for DL channel measurement, and the UE may report (e.g., feedback) information about channel measurement, e.g., CSI, to the gNB.
  • CSI-RS reference signal
  • the gNB is able to select appropriate communication parameters to efficiently and effectively perform wireless data communication with the UE.
  • Embodiments of the present disclosure provide methods and apparatuses to enable channel state information (CSI) reporting based on a codebook for distributed MIMO transmission in a wireless communication system.
  • CSI channel state information
  • the UE further includes a processor operably connected to the transceiver. The processor, based on the information, is configured to: select a strongest RRH from the RRHs; and determine the CSI report including an indicator indicating the strongest RRH.
  • the transceiver is further configured to transmit the CSI report including the indicator indicating the strongest RRH.
  • the BS further includes a transceiver operably connected to the processor. The transceiver is configured to: transmit the information; and receive the CSI report, wherein the CSI report includes an indicator indicating a strongest RRH selected from the RRHs.
  • CSI channel state information
  • FIGURE 1 illustrates an example wireless network according to embodiments of the present disclosure
  • FIGURE 2 illustrates an example gNB according to embodiments of the present disclosure
  • FIGURE 3 illustrates an example UE according to embodiments of the present disclosure
  • FIGURE 4A illustrates a high-level diagram of an orthogonal frequency division multiple access transmit path according to embodiments of the present disclosure
  • FIGURE 4B illustrates a high-level diagram of an orthogonal frequency division multiple access receive path according to embodiments of the present disclosure
  • FIGURE 5 illustrates a transmitter block diagram for a PDSCH in a subframe according to embodiments of the present disclosure
  • FIGURE 6 illustrates a receiver block diagram for a PDSCH in a subframe according to embodiments of the present disclosure
  • FIGURE 7 illustrates a transmitter block diagram for a PUSCH in a subframe according to embodiments of the present disclosure
  • FIGURE 8 illustrates a receiver block diagram for a PUSCH in a subframe according to embodiments of the present disclosure
  • FIGURE 9 illustrates an example antenna blocks or arrays forming beams according to embodiments of the present disclosure
  • FIGURE 10 illustrates an example distributed MIMO (D-MIMO) system according to embodiments of the present disclosure
  • FIGURE 11 illustrates an example antenna port layout according to embodiments of the present disclosure
  • FIGURE 12 illustrates an example of Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission according to embodiments of the present disclosure
  • FIGURE 13 illustrates an example D-MIMO where each RRH has a single antenna panel according to embodiments of the present disclosure
  • FIGURE 14 illustrates an example D-MIMO where each RRH has multiple antenna panels according to embodiments of the present disclosure
  • FIGURE 15 illustrates an example D-MIMO where each RRH can have a single antenna panel or multiple antenna panels according to embodiments of the present disclosure
  • FIGURE 16 illustrates a flow chart of a method for operating a UE according to embodiments of the present disclosure.
  • FIGURE 17 illustrates a flow chart of a method for operating a BS according to embodiments of the present disclosure.
  • Couple and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another.
  • transmit and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication.
  • the term “or” is inclusive, meaning and/or.
  • controller means any 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 any particular controller may be centralized or distributed, whether locally or remotely.
  • phrases "at least one of,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed.
  • “at least one of: A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.
  • various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium.
  • application and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code.
  • computer readable program code includes any type of computer code, including source code, object code, and executable code.
  • computer readable medium includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory.
  • ROM read only memory
  • RAM random access memory
  • CD compact disc
  • DVD digital video disc
  • a "non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals.
  • a non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.
  • FIGURES 1 through FIGURE 17, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.
  • 3GPP TS 36.211 v16.6.0 “E-UTRA, Physical channels and modulation” (herein “REF 1”); 3GPP TS 36.212 v16.6.0, “E-UTRA, Multiplexing and Channel coding” (herein “REF 2”); 3GPP TS 36.213 v16.6.0, “E-UTRA, Physical Layer Procedures” (herein “REF 3”); 3GPP TS 36.321 v16.6.0, “E-UTRA, Medium Access Control (MAC) protocol specification” (herein “REF 4"); 3GPP TS 36.331 v16.6.0, “E-UTRA, Radio Resource Control (RRC) protocol specification” (herein “REF 5"); 3GPP TR 22.891 v14.2.0 (herein “REF 6”); 3GPP TS 38.212 v16.6.0, “E-UTRA, NR, Multiplex
  • both FDD and TDD are considered as the duplex method for both DL and UL signaling.
  • orthogonal frequency division multiplexing OFDM
  • orthogonal frequency division multiple access OFDMA
  • F-OFDM filtered OFDM
  • 5G/NR communication systems To meet the demand for wireless data traffic having increased since deployment of 4G communication systems and to enable various vertical applications, 5G/NR communication systems have been developed and are currently being deployed.
  • the 5G/NR communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60GHz bands, so as to accomplish higher data rates or in lower frequency bands, such as 6 GHz, to enable robust coverage and mobility support.
  • mmWave mmWave
  • 6 GHz lower frequency bands
  • the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G/NR communication systems.
  • RANs cloud radio access networks
  • D2D device-to-device
  • wireless backhaul moving network
  • CoMP coordinated multi-points
  • 5G systems and frequency bands associated therewith are for reference as certain embodiments of the present disclosure may be implemented in 5G systems.
  • the present disclosure is not limited to 5G systems or the frequency bands associated therewith, and embodiments of the present disclosure may be utilized in connection with any frequency band.
  • aspects of the present disclosure may also be applied to deployment of 5G communication systems, 6G or even later releases which may use terahertz (THz) bands.
  • THz terahertz
  • FIGURES 1-4B below describe various embodiments implemented in wireless communications systems and with the use of orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication techniques.
  • OFDM orthogonal frequency division multiplexing
  • OFDMA orthogonal frequency division multiple access
  • FIGURE 1 illustrates an example wireless network according to embodiments of the present disclosure.
  • the embodiment of the wireless network shown in FIGURE 1 is for illustration only. Other embodiments of the wireless network 100 could be used without departing from the scope of this disclosure.
  • the wireless network includes a gNB 101, a gNB 102, and a gNB 103.
  • the gNB 101 communicates with the gNB 102 and the gNB 103.
  • the gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.
  • IP Internet Protocol
  • the gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipments (UEs) within a coverage area 120 of the gNB 102.
  • the first plurality of UEs includes a UE 111, which may be located in a small business; a UE 112, which may be located in an enterprise (E); a UE 113, which may be located in a WiFi hotspot (HS); a UE 114, which may be located in a first residence (R); a UE 115, which may be located in a second residence (R); and a UE 116, which may be a mobile device (M), such as a cell phone, a wireless laptop, a wireless PDA, or the like.
  • M mobile device
  • the gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103.
  • the second plurality of UEs includes the UE 115 and the UE 116.
  • one or more of the gNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G, LTE, LTE-A, WiMAX, WiFi, or other wireless communication techniques.
  • the term “base station” or “BS” can refer to any component (or collection of components) configured to provide wireless access to a network, such as transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wirelessly enabled devices.
  • Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., 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.
  • 5G 3GPP new radio interface/access NR
  • LTE long term evolution
  • LTE-A LTE advanced
  • HSPA high speed packet access
  • Wi-Fi 802.11a/b/g/n/ac etc.
  • the terms “BS” and “TRP” are used interchangeably in this patent document to refer to network infrastructure components that provide wireless access to remote terminals.
  • the term “user equipment” or “UE” can refer to any component such as “mobile station,” “subscriber station,” “remote terminal,” “wireless terminal,” “receive point,” or “user device.”
  • the terms “user equipment” and “UE” are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).
  • Dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending upon the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.
  • CSI channel state information
  • CSI channel state information
  • FIGURE 1 illustrates one example of a wireless network
  • the wireless network could include any number of gNBs and any number of UEs in any suitable arrangement.
  • the gNB 101 could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network 130.
  • each gNB 102-103 could communicate directly with the network 130 and provide UEs with direct wireless broadband access to the network 130.
  • the gNBs 101, 102, and/or 103 could provide access to other or additional external networks, such as external telephone networks or other types of data networks.
  • FIGURE 2 illustrates an example gNB 102 according to embodiments of the present disclosure.
  • the embodiment of the gNB 102 illustrated in FIGURE 2 is for illustration only, and the gNBs 101 and 103 of FIGURE 1 could have the same or similar configuration.
  • gNBs come in a wide variety of configurations, and FIGURE 2 does not limit the scope of this disclosure to any particular implementation of a gNB.
  • the gNB 102 includes multiple antennas 205a-205n, multiple RF transceivers 210a-210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220.
  • the gNB 102 also includes a controller/processor 225, a memory 230, and a backhaul or network interface 235.
  • the RF transceivers 210a-210n receive, from the antennas 205a-205n, incoming RF signals, such as signals transmitted by UEs in 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 sent to the RX processing circuitry 220, which generates processed baseband signals by filtering, decoding, and/or digitizing the baseband or IF signals.
  • the RX processing circuitry 220 transmits the processed baseband signals to the controller/processor 225 for further processing.
  • the TX processing circuitry 215 receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor 225.
  • the TX processing circuitry 215 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals.
  • the RF transceivers 210a-210n receive the outgoing processed baseband or IF signals from the TX processing circuitry 215 and up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 205a-205n.
  • the controller/processor 225 can include one or more processors or other processing devices that control the overall operation of the gNB 102.
  • the controller/processor 225 could control the reception of UL channel signals and the transmission of DL channel signals by the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 in accordance with well-known principles.
  • the controller/processor 225 could support additional functions as well, such as more advanced wireless communication functions.
  • the controller/processor 225 could support beam forming or directional routing operations in which outgoing signals from multiple antennas 205a-205n are weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions could be supported in the gNB 102 by the controller/processor 225.
  • the controller/processor 225 is also capable of executing programs and other processes resident in the memory 230, such as an OS.
  • the controller/processor 225 can move data into or out of the memory 230 as required by an executing process.
  • the controller/processor 225 is also coupled to the backhaul or network interface 235.
  • the backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network.
  • the interface 235 could support communications over any suitable wired or wireless connection(s). For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G, LTE, or LTE-A), the interface 235 could allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection.
  • the interface 235 could allow the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet).
  • the interface 235 includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or RF transceiver.
  • the memory 230 is coupled to the controller/processor 225. Part of the memory 230 could include a RAM, and another part of the memory 230 could include a Flash memory or other ROM.
  • FIGURE 2 illustrates one example of gNB 102
  • the gNB 102 could include any number of each component shown in FIGURE 2.
  • an access point could include a number of interfaces 235, and the controller/processor 225 could support routing functions to route data between different network addresses.
  • the gNB 102 while shown as including a single instance of TX processing circuitry 215 and a single instance of RX processing circuitry 220, the gNB 102 could include multiple instances of each (such as one per RF transceiver).
  • various components in FIGURE 2 could be combined, further subdivided, or omitted and additional components could be added according to particular needs.
  • FIGURE 3 illustrates an example UE 116 according to embodiments of the present disclosure.
  • the embodiment of the UE 116 illustrated in FIGURE 3 is for illustration only, and the UEs 111-115 of FIGURE 1 could have the same or similar configuration.
  • UEs come in a wide variety of configurations, and FIGURE 3 does not limit the scope of this disclosure to any particular implementation of a UE.
  • the UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, TX processing circuitry 315, a microphone 320, and receive (RX) processing circuitry 325.
  • the UE 116 also 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 operating system (OS) 361 and one or more applications 362.
  • the RF transceiver 310 receives, from the antenna 305, an incoming RF signal transmitted by a gNB of the network 100.
  • the RF transceiver 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal.
  • the IF or baseband signal is sent 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 (such as for voice data) or to the processor 340 for further processing (such as for web browsing data).
  • the TX processing circuitry 315 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor 340.
  • the TX processing circuitry 315 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband or IF signal.
  • the RF transceiver 310 receives the outgoing processed baseband or IF signal from the TX processing circuitry 315 and up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna 305.
  • the processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116.
  • the processor 340 could control the reception of DL channel signals and the transmission of UL channel signals by the RF transceiver 310, the RX processing circuitry 325, and the TX processing circuitry 315 in accordance with well-known principles.
  • the processor 340 includes at least one microprocessor or microcontroller.
  • the processor 340 can move data into or out of the memory 360 as required by an executing process.
  • the processor 340 is configured to execute the applications 362 based on the OS 361 or in response to signals received from gNBs or an operator.
  • the processor 340 is also coupled to the I/O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers.
  • the I/O interface 345 is the communication path between these accessories and the processor 340.
  • the processor 340 is also coupled to the touchscreen 350 and the display 355.
  • the operator of the UE 116 can use the touchscreen 350 to enter data into the UE 116.
  • the display 355 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and/or at least limited graphics, such as from web sites.
  • the memory 360 is coupled to the processor 340.
  • Part of the memory 360 could include a random access memory (RAM), and another part of the memory 360 could include a Flash memory or other read-only memory (ROM).
  • RAM random access memory
  • ROM read-only memory
  • FIGURE 3 illustrates one example of UE 116
  • various changes may be made to FIGURE 3.
  • various components in FIGURE 3 could be combined, further subdivided, or omitted and additional components could be added according to particular needs.
  • the processor 340 could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs).
  • FIGURE 3 illustrates the UE 116 configured as a mobile telephone or smartphone, UEs could be configured to operate as other types of mobile or stationary devices.
  • FIGURE 4A is a high-level diagram of transmit path circuitry.
  • the transmit path circuitry may be used for an orthogonal frequency division multiple access (OFDMA) communication.
  • FIGURE 4B is a high-level diagram of receive path circuitry.
  • the receive path circuitry may be used for an orthogonal frequency division multiple access (OFDMA) communication.
  • the transmit path circuitry may be implemented in a base station (gNB) 102 or a relay station, and the receive path circuitry may be implemented in a user equipment (e.g., user equipment 116 of FIGURE 1).
  • gNB base station
  • the receive path circuitry may be implemented in a user equipment (e.g., user equipment 116 of FIGURE 1).
  • the receive path circuitry 450 may be implemented in a base station (e.g., gNB 102 of FIGURE 1) or a relay station, and the transmit path circuitry may be implemented in a user equipment (e.g., user equipment 116 of FIGURE 1).
  • a base station e.g., gNB 102 of FIGURE 1
  • the transmit path circuitry may be implemented in a user equipment (e.g., user equipment 116 of FIGURE 1).
  • Transmit path circuitry comprises channel coding and modulation block 405, serial-to-parallel (S-to-P) block 410, Size N Inverse Fast Fourier Transform (IFFT) block 415, parallel-to-serial (P-to-S) block 420, add cyclic prefix block 425, and up-converter (UC) 430.
  • Receive path circuitry 450 comprises down-converter (DC) 455, remove cyclic prefix block 460, serial-to-parallel (S-to-P) block 465, Size N Fast Fourier Transform (FFT) block 470, parallel-to-serial (P-to-S) block 475, and channel decoding and demodulation block 480.
  • DC down-converter
  • FFT Fast Fourier Transform
  • FIGURES 4A 400 and 4B 450 may be implemented in software, while other components may be implemented by configurable hardware or a mixture of software and configurable hardware.
  • the FFT blocks and the IFFT blocks described in this disclosure document may be implemented as configurable software algorithms, where the value of Size N may be modified according to the implementation.
  • the value of the N variable may be any integer number (i.e., 1, 4, 3, 4, etc.), while for FFT and IFFT functions, the value of the N variable may be any integer number that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).
  • channel coding and modulation block 405 receives a set of information bits, applies coding (e.g., LDPC coding) and modulates (e.g., quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)) the input bits to produce a sequence of frequency-domain modulation symbols.
  • Serial-to-parallel block 410 converts (i.e., de-multiplexes) the serial modulated symbols to parallel data to produce N parallel symbol streams where N is the IFFT/FFT size used in BS 102 and UE 116.
  • Size N IFFT block 415 then performs an IFFT operation on the N parallel symbol streams to produce time-domain output signals.
  • Parallel-to-serial block 420 converts (i.e., multiplexes) the parallel time-domain output symbols from Size N IFFT block 415 to produce a serial time-domain signal.
  • Add cyclic prefix block 425 then inserts a cyclic prefix to the time-domain signal.
  • up-converter 430 modulates (i.e., up-converts) the output of add cyclic prefix block 425 to RF frequency for transmission via a wireless channel.
  • the signal may also be filtered at baseband before conversion to RF frequency.
  • the transmitted RF signal arrives at the UE 116 after passing through the wireless channel, and reverse operations to those at gNB 102 are performed.
  • Down-converter 455 down-converts the received signal to baseband frequency and removes cyclic prefix block 460, and removes the cyclic prefix to produce the serial time-domain baseband signal.
  • Serial-to-parallel block 465 converts the time-domain baseband signal to parallel time-domain signals.
  • Size N FFT block 470 then performs an FFT algorithm to produce N parallel frequency-domain signals.
  • Parallel-to-serial block 475 converts the parallel frequency-domain signals to a sequence of modulated data symbols.
  • Channel decoding and demodulation block 480 demodulates and then decodes the modulated symbols to recover the original input data stream.
  • Each of gNBs 101-103 may implement a transmit path that is analogous to transmitting in the downlink to user equipment 111-116 and may implement a receive path that is analogous to receiving in the uplink from user equipment 111-116.
  • each one of user equipment 111-116 may implement a transmit path corresponding to the architecture for transmitting in the uplink to gNBs 101-103 and may implement a receive path corresponding to the architecture for receiving in the downlink from gNBs 101-103.
  • a communication system includes a downlink (DL) that conveys signals from transmission points such as base stations (BSs) or NodeBs to user equipments (UEs) and an Uplink (UL) that conveys signals from UEs to reception points such as NodeBs.
  • DL downlink
  • UE user equipment
  • UL Uplink
  • a UE also commonly referred to as a terminal or a mobile station, may be fixed or mobile and may be a cellular phone, a personal computer device, or an automated device.
  • An eNodeB which is generally a fixed station, may also be referred to as an access point or other equivalent terminology. For LTE systems, a NodeB is often referred as an eNodeB.
  • DL signals can include data signals conveying information content, control signals conveying DL control information (DCI), and reference signals (RS) that are also known as pilot signals.
  • DCI DL control information
  • RS reference signals
  • An eNodeB transmits data information through a physical DL shared channel (PDSCH).
  • An eNodeB transmits DCI through a physical DL control channel (PDCCH) or an Enhanced PDCCH (EPDCCH).
  • PDSCH physical DL shared channel
  • EPCCH Enhanced PDCCH
  • An eNodeB transmits acknowledgement information in response to data transport block (TB) transmission from a UE in a physical hybrid ARQ indicator channel (PHICH).
  • An eNodeB transmits one or more of multiple types of RS including a UE-common RS (CRS), a channel state information RS (CSI-RS), or a demodulation RS (DMRS).
  • CRS is transmitted over a DL system bandwidth (BW) and can be used by UEs to obtain a channel estimate to demodulate data or control information or to perform measurements.
  • BW DL system bandwidth
  • an eNodeB may transmit a CSI-RS with a smaller density in the time and/or frequency domain than a CRS.
  • DMRS can be transmitted only in the BW of a respective PDSCH or EPDCCH and a UE can use the DMRS to demodulate data or control information in a PDSCH or an EPDCCH, respectively.
  • a transmission time interval for DL channels is referred to as a subframe and can have, for example, duration of 1 millisecond.
  • DL signals also include transmission of a logical channel that carries system control information.
  • a BCCH is mapped to either a transport channel referred to as a broadcast channel (BCH) when the DL signals convey a master information block (MIB) or to a DL shared channel (DL-SCH) when the DL signals convey a System Information Block (SIB).
  • MIB master information block
  • DL-SCH DL shared channel
  • SIB System Information Block
  • Most system information is included in different SIBs that are transmitted using DL-SCH.
  • a presence of system information on a DL-SCH in a subframe can be indicated by a transmission of a corresponding PDCCH conveying a codeword with a cyclic redundancy check (CRC) scrambled with system information RNTI (SI-RNTI).
  • SI-RNTI system information RNTI
  • SIB-1 scheduling information for the first SIB (SIB-1) can be provided by the MIB.
  • a DL resource allocation is performed in a unit of subframe and a group of physical resource blocks (PRBs).
  • a transmission BW includes frequency resource units referred to as resource blocks (RBs).
  • Each RB includes sub-carriers, or resource elements (REs), such as 12 REs.
  • a unit of one RB over one subframe is referred to as a PRB.
  • a UE can be allocated RBs for a total of REs for the PDSCH transmission BW.
  • UL signals can include data signals conveying data information, control signals conveying UL control information (UCI), and UL RS.
  • UL RS includes DMRS and Sounding RS (SRS).
  • a UE transmits DMRS only in a BW of a respective PUSCH or PUCCH.
  • An eNodeB can use a DMRS to demodulate data signals or UCI signals.
  • a UE transmits SRS to provide an eNodeB with an UL CSI.
  • a UE transmits data information or UCI through a respective physical UL shared channel (PUSCH) or a Physical UL control channel (PUCCH). If a UE needs to transmit data information and UCI in a same UL subframe, the UE may multiplex both in a PUSCH.
  • PUSCH physical UL shared channel
  • PUCCH Physical UL control channel
  • UCI includes Hybrid Automatic Repeat request acknowledgement (HARQ-ACK) information, indicating correct (ACK) or incorrect (NACK) detection for a data TB in a PDSCH or absence of a PDCCH detection (DTX), scheduling request (SR) indicating whether a UE has data in the UE's buffer, rank indicator (RI), and channel state information (CSI) enabling an eNodeB to perform link adaptation for PDSCH transmissions to a UE.
  • HARQ-ACK information is also transmitted by a UE in response to a detection of a PDCCH/EPDCCH indicating a release of semi-persistently scheduled PDSCH.
  • An UL subframe includes two slots. Each slot includes symbols for transmitting data information, UCI, DMRS, or SRS.
  • a frequency resource unit of an UL system BW is a RB.
  • a UE is allocated RBs for a total of REs for a transmission BW.
  • For a PUCCH .
  • a last subframe symbol can be used to multiplex SRS transmissions from one or more UEs.
  • a number of subframe symbols that are available for data/UCI/DMRS transmission is , where if a last subframe symbol is used to transmit SRS and otherwise.
  • FIGURE 5 illustrates a transmitter block diagram 500 for a PDSCH in a subframe according to embodiments of the present disclosure.
  • the embodiment of the transmitter block diagram 500 illustrated in FIGURE 5 is for illustration only.
  • One or more of the components illustrated in FIGURE 5 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.
  • FIGURE 5 does not limit the scope of this disclosure to any particular implementation of the transmitter block diagram 500.
  • information bits 510 are encoded by encoder 520, such as a turbo encoder, and modulated by modulator 530, for example using quadrature phase shift keying (QPSK) modulation.
  • a serial to parallel (S/P) converter 540 generates M modulation symbols that are subsequently provided to a mapper 550 to be mapped to REs selected by a transmission BW selection unit 555 for an assigned PDSCH transmission BW, unit 560 applies an Inverse fast Fourier transform (IFFT), the output is then serialized by a parallel to serial (P/S) converter 570 to create a time domain signal, filtering is applied by filter 580, and a signal transmitted 590.
  • Additional functionalities such as data scrambling, cyclic prefix insertion, time windowing, interleaving, and others are well known in the art and are not shown for brevity.
  • FIGURE 6 illustrates a receiver block diagram 600 for a PDSCH in a subframe according to embodiments of the present disclosure.
  • the embodiment of the diagram 600 illustrated in FIGURE 6 is for illustration only.
  • One or more of the components illustrated in FIGURE 6 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.
  • FIGURE 6 does not limit the scope of this disclosure to any particular implementation of the diagram 600.
  • a received signal 610 is filtered by filter 620, REs 630 for an assigned reception BW are selected by BW selector 635, unit 640 applies a fast Fourier transform (FFT), and an output is serialized by a parallel-to-serial converter 650.
  • a demodulator 660 coherently demodulates data symbols by applying a channel estimate obtained from a DMRS or a CRS (not shown), and a decoder 670, such as a turbo decoder, decodes the demodulated data to provide an estimate of the information data bits 680. Additional functionalities such as time-windowing, cyclic prefix removal, de-scrambling, channel estimation, and de-interleaving are not shown for brevity.
  • FIGURE 7 illustrates a transmitter block diagram 700 for a PUSCH in a subframe according to embodiments of the present disclosure.
  • the embodiment of the block diagram 700 illustrated in FIGURE 7 is for illustration only.
  • One or more of the components illustrated in FIGURE 5 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.
  • FIGURE 7 does not limit the scope of this disclosure to any particular implementation of the block diagram 700.
  • information data bits 710 are encoded by encoder 720, such as a turbo encoder, and modulated by modulator 730.
  • a discrete Fourier transform (DFT) unit 740 applies a DFT on the modulated data bits, REs 750 corresponding to an assigned PUSCH transmission BW are selected by transmission BW selection unit 755, unit 760 applies an IFFT and, after a cyclic prefix insertion (not shown), filtering is applied by filter 770 and a signal transmitted 780.
  • DFT discrete Fourier transform
  • FIGURE 8 illustrates a receiver block diagram 800 for a PUSCH in a subframe according to embodiments of the present disclosure.
  • the embodiment of the block diagram 800 illustrated in FIGURE 8 is for illustration only.
  • One or more of the components illustrated in FIGURE 8 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.
  • FIGURE 8 does not limit the scope of this disclosure to any particular implementation of the block diagram 800.
  • a received signal 810 is filtered by filter 820. Subsequently, after a cyclic prefix is removed (not shown), unit 830 applies a FFT, REs 840 corresponding to an assigned PUSCH reception BW are selected by a reception BW selector 845, unit 850 applies an inverse DFT (IDFT), a demodulator 860 coherently demodulates data symbols by applying a channel estimate obtained from a DMRS (not shown), a decoder 870, such as a turbo decoder, decodes the demodulated data to provide an estimate of the information data bits 880.
  • a decoder 870 such as a turbo decoder
  • next generation cellular systems various use cases are envisioned beyond the capabilities of LTE system.
  • 5G or the fifth generation cellular system a system capable of operating at sub-6GHz and above-6 GHz (for example, in mmWave regime) becomes one of the requirements.
  • 3GPP TR 22.891 74 5G use cases have been identified and described; those use cases can be roughly categorized into three different groups.
  • a first group is termed “enhanced mobile broadband (eMBB),” targeted to high data rate services with less stringent latency and reliability requirements.
  • eMBB enhanced mobile broadband
  • URLL ultra-reliable and low latency
  • a third group is termed “massive MTC (mMTC)” targeted for large number of low-power device connections such as 1 million per km 2 with less stringent the reliability, data rate, and latency requirements.
  • mMTC massive MTC
  • FIGURE 9 illustrates an example antenna blocks or arrays 900 according to embodiments of the present disclosure.
  • the embodiment of the antenna blocks or arrays 900 illustrated in FIGURE 9 is for illustration only.
  • FIGURE 9 does not limit the scope of this disclosure to any particular implementation of the antenna blocks or arrays 900.
  • the number of CSI-RS ports - which can correspond to the number of digitally precoded ports - tends to be limited due to hardware constraints (such as the feasibility to install a large number of ADCs/DACs at mmWave frequencies) as illustrated in FIGURE 9.
  • one CSI-RS port is mapped onto a large number of antenna elements which can be controlled by a bank of analog phase shifters 901.
  • One CSI-RS port can then correspond to one sub-array which produces a narrow analog beam through analog beamforming 905.
  • This analog beam can be configured to sweep across a wider range of angles (920) by varying the phase shifter bank across symbols or subframes.
  • the number of sub-arrays (equal to the number of RF chains) is the same as the number of CSI-RS ports N CSI-PORT .
  • a digital beamforming unit 910 performs a linear combination across N CSI-PORT analog beams to further increase precoding gain. While analog beams are wideband (hence not frequency-selective), digital precoding can be varied across frequency sub-bands or resource blocks.
  • NP non-precoded
  • CSI-RS For non-precoded (NP) CSI-RS, a cell-specific one-to-one mapping between CSI-RS port and TXRU is utilized. Different CSI-RS ports have the same wide beam width and direction and hence generally cell wide coverage.
  • beamformed CSI-RS beamforming operation, either cell-specific or UE-specific, is applied on a non-zero-power (NZP) CSI-RS resource (e.g., comprising multiple ports). At least at a given time/frequency, CSI-RS ports have narrow beam widths and hence not cell wide coverage, and at least from the gNB perspective. At least some CSI-RS port-resource combinations have different beam directions.
  • NZP non-zero-power
  • UE-specific BF CSI-RS can be readily used. This is typically feasible when UL-DL duplex distance is sufficiently small. When this condition does not hold, however, some UE feedback is necessary for the eNodeB to obtain an estimate of DL long-term channel statistics (or any of representation thereof).
  • T1 periodicity
  • T2 periodicity
  • MIMO is often identified as an essential feature in order to achieve high system throughput requirements.
  • One of the key components of a MIMO transmission scheme is the accurate CSI acquisition at the eNB (or gNB) (or TRP).
  • the CSI can be acquired using the SRS transmission relying on the channel reciprocity.
  • the CSI-RS transmission from eNB (or gNB), and CSI acquisition and feedback from UE.
  • the CSI feedback framework is ' implicit ' in the form of CQI/PMI/RI (also CRI and LI) derived from a codebook assuming SU transmission from eNB (or gNB). Because of the inherent SU assumption while deriving CSI, this implicit CSI feedback is inadequate for MU transmission. Since future (e.g., NR) systems are likely to be more MU-centric, this SU-MU CSI mismatch will be a bottleneck in achieving high MU performance gains. Another issue with implicit feedback is the scalability with larger number of antenna ports at eNB (or gNB).
  • the codebook design for implicit feedback is quite complicated (for example, a total number of 44 Class A codebooks in the 3GPP LTE specification), and the designed codebook is not guaranteed to bring justifiable performance benefits in practical deployment scenarios (for example, only a small percentage gain can be shown at the most).
  • the 3GPP specification also supports advanced CSI reporting in LTE.
  • Type II CSI reporting In 5G or NR systems [REF7, REF8], the above-mentioned "implicit" CSI reporting paradigm from LTE is also supported and referred to as Type I CSI reporting.
  • a high-resolution CSI reporting referred to as Type II CSI reporting
  • Type II CSI reporting is also supported to provide more accurate CSI information to gNB for use cases such as high-order MU-MIMO.
  • the overhead of Type II CSI reporting can be an issue in practical UE implementations.
  • One approach to reduce Type II CSI overhead is based on frequency domain (FD) compression.
  • FD frequency domain
  • Rel. 16 NR DFT-based FD compression of the Type II CSI has been supported (referred to as Rel. 16 enhanced Type II codebook in REF8).
  • Some of the key components for this feature includes (a) spatial domain (SD) basis , (b) FD basis , and (c) coefficients that linearly combine SD and FD basis.
  • SD spatial domain
  • FD FD
  • coefficients that linearly combine SD and FD basis In a non-reciprocal FDD system, a complete CSI (comprising all components) needs to be reported by the UE. However, when reciprocity or partial reciprocity does exist between UL and DL, then some of the CSI components can be obtained based on the UL channel estimated using SRS transmission from the UE. In Rel. 16 NR, the DFT-based FD compression is extended to this partial reciprocity case (referred to as Rel.
  • the CSI-RS ports in this case are beamformed in SD (assuming UL-DL channel reciprocity in angular domain), and the beamforming information can be obtained at the gNB based on UL channel estimated using SRS measurements.
  • FIGURE 10 illustrates an example distributed MIMO (D-MIMO) system 1000 according to embodiments of the present disclosure.
  • the embodiment of the distributed MIMO (D-MIMO) system 1000 illustrated in FIGURE 10 is for illustration only.
  • FIGURE 10 does not limit the scope of this disclosure to any particular implementation of the distributed MIMO (D-MIMO) system 1000.
  • NR supports up to 32 CSI-RS antenna ports.
  • a cellular system operating in a sub-1GHz frequency range e.g., less than 1 GHz
  • supporting a large number of CSI-RS antenna ports e.g., 32
  • RRH remote radio head
  • the maximum number of CSI-RS antenna ports that can be co-located at a site (or RRH) can be limited, for example to 8. This limits the spectral efficiency of such systems.
  • the MU-MIMO spatial multiplexing gains offered due to large number of CSI-RS antenna ports can't be achieved.
  • One way to operate a sub-1GHz system with large number of CSI-RS antenna ports is based on distributing antenna ports at multiple sites (or RRHs).
  • the multiple sites or RRHs can still be connected to a single (common) baseband unit, hence the signal transmitted/received via multiple distributed RRHs can still be processed at a centralized location.
  • 32 CSI-RS ports can be distributed across 4 RRHs, each with 8 antenna ports.
  • Such a MIMO system can be referred to as a distributed MIMO (D-MIMO) system as illustrated in FIGURE 10.
  • D-MIMO distributed MIMO
  • All the following components and embodiments are applicable for UL transmission with CP-OFDM (cyclic prefix OFDM) waveform as well as DFT-SOFDM (DFT-spread OFDM) and SC-FDMA (single-carrier FDMA) waveforms. Furthermore, all the following components and embodiments are applicable for UL transmission when the scheduling unit in time is either one subframe (which can consist of one or multiple slots) or one slot.
  • CP-OFDM cyclic prefix OFDM
  • DFT-SOFDM DFT-spread OFDM
  • SC-FDMA single-carrier FDMA
  • the frequency resolution (reporting granularity) and span (reporting bandwidth) of CSI reporting can be defined in terms of frequency “subbands” and “CSI reporting band” (CRB), respectively.
  • a subband for CSI reporting is defined as a set of contiguous PRBs which represents the smallest frequency unit for CSI reporting.
  • the number of PRBs in a subband can be fixed for a given value of DL system bandwidth, configured either semi-statically via higher-layer/RRC signaling, or dynamically via L1 DL control signaling or MAC control element (MAC CE).
  • the number of PRBs in a subband can be included in CSI reporting setting.
  • CSI reporting band is defined as a set/collection of subbands, either contiguous or non-contiguous, wherein CSI reporting is performed.
  • CSI reporting band can include all the subbands within the DL system bandwidth. This can also be termed “full-band”.
  • CSI reporting band can include only a collection of subbands within the DL system bandwidth. This can also be termed “partial band”.
  • CSI reporting band is used only as an example for representing a function. Other terms such as “CSI reporting subband set” or “CSI reporting bandwidth” can also be used.
  • a UE can be configured with at least one CSI reporting band.
  • This configuration can be semi-static (via higher-layer signaling or RRC) or dynamic (via MAC CE or L1 DL control signaling).
  • RRC higher-layer signaling
  • a UE can report CSI associated with n ⁇ N CSI reporting bands. For instance, > 6GHz, large system bandwidth may require multiple CSI reporting bands.
  • the value of n can either be configured semi-statically (via higher-layer signaling or RRC) or dynamically (via MAC CE or L1 DL control signaling). Alternatively, the UE can report a recommended value of n via an UL channel.
  • CSI parameter frequency granularity can be defined per CSI reporting band as follows.
  • a CSI parameter is configured with "single" reporting for the CSI reporting band with M n subbands when one CSI parameter for all the M n subbands within the CSI reporting band.
  • a CSI parameter is configured with "subband” for the CSI reporting band with M n subbands when one CSI parameter is reported for each of the M n subbands within the CSI reporting band.
  • FIGURE 11 illustrates an example antenna port layout 1100 according to embodiments of the present disclosure.
  • the embodiment of the antenna port layout 1100 illustrated in FIGURE 11 is for illustration only.
  • FIGURE 11 does not limit the scope of this disclosure to any particular implementation of the antenna port layout 1100.
  • N 1 and N 2 are the number of antenna ports with the same polarization in the first and second dimensions, respectively.
  • N 1 > 1, N 2 > 1, and for 1D antenna port layouts N 1 > 1 and N 2 1. Therefore, for a dual-polarized antenna port layout, the total number of antenna ports is 2N 1 N 2 when each antenna maps to an antenna port.
  • An illustration is shown in FIGURE 11 where "X" represents two antenna polarizations. In this disclosure, the term “polarization" refers to a group of antenna ports.
  • antenna ports comprise a first antenna polarization
  • antenna ports comprise a second antenna polarization, where is a number of CSI-Rs antenna ports and is a starting antenna port number (e.g., , then antenna ports are 3000, 3001, 3002, ).
  • each panel is dual-polarized antenna ports with and ports in two dimensions. This is illustrated in FIGURE 11. Note that the antenna port layouts may or may not be the same in different antenna panels.
  • the Type I single-panel codebook has the following rank 1 (1-layer) pre-coder structure:
  • the supported values of is a two-dimensional DFT vector.
  • the supported values of is , which corresponds to QPSK co-phase .
  • the supported values of is given by Table 1.
  • FIGURE 12 An illustration of Rel. 15 Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission is shown in FIGURE 12. It will be understood by those skilled in the art that FIGURE 12 illustrates an example Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission 1200 according to embodiments of the present disclosure.
  • the embodiment of the Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission 1200 illustrated in FIGURE 12 is for illustration only. FIGURE 12 does not limit the scope of this disclosure to any particular implementation of the Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission 1200.
  • the antenna architecture of a D-MIMO system is structured.
  • the antenna structure at each RRH is dual-polarized (single or multi-panel as shown in FIGURE 11.
  • the antenna structure at each RRH can be the same.
  • the antenna structure at an RRH can be different from another RRH.
  • the number of ports at each RRH can be the same.
  • the number of ports of one RRH can be different from another RRH.
  • the antenna architecture of a D-MIMO system is unstructured.
  • the antenna structure at one RRH can be different from another RRH.
  • a UE is configured with a D-MIMO codebook (e.g., via higher layer signaling), wherein a value for the number of RRHs is parameterized by .
  • a value of is configured, e.g., as part of the codebook configuration or CSI reporting configuration via RRC signaling, or indicated via MAC CE or DCI or a combination of two or more of RRC, MAC CE and DCI.
  • the value of is configured from a set of supported values. In one example, the set of supported values is or or or .
  • a separate RRC parameter is used to configure a value for .
  • a joint RRC parameter is used to configure a value for and a value for at least one additional parameter.
  • the parameter in Rel. 15 Type I multi-panel codebook can be used as a joint parameter for both and .
  • a value of (whether fixed or configured) is subject to a constraint (or condition).
  • the total number of ports across all RRHs belongs to a set of values or or or .
  • the total number of ports across all RRHs is determined according to at least one of the following examples.
  • the antenna structure is the same at each RRH, i.e., for all . In one example, where is a parameter for -th RRH, assuming that the antenna structure can be different across RRHs, i.e., .
  • the parameter can be configured via RRC, e.g., based on Table 1 for Rel. 15 Type I single panel (or multi-panel) codebook.
  • the parameters for each can be configured via RRC, e.g., based on Table 1 for Rel. 15 Type I single panel (or multi-panel) codebook.
  • the antenna structure is the same at each RRH, i.e., for all .
  • a parameter for -th RRH assuming that the antenna structure can be different across RRHs.
  • the parameter can be configured via RRC, e.g., from ⁇ 2,4,8,12,16,24,32 ⁇ or ⁇ 4,8,12,16,24,32 ⁇ .
  • the parameter for each can be configured via RRC, e.g., from ⁇ 2,4,8,12,16,24,32 ⁇ or ⁇ 4,8,12,16,24,32 ⁇ .
  • values are such that belongs to ⁇ 4,8,12,16,24,32 ⁇ or ⁇ 4,8,12,16,24,32,48 ⁇ or ⁇ 4,8,12,16,24,32,48,64 ⁇ or ⁇ 8,12,16,24,32 ⁇ or ⁇ 8,12,16,24,32,48 ⁇ or ⁇ 8,12,16,24,32,48,64 ⁇ .
  • values for and different values of the total number of CSI-RS ports is according to at least one of the examples in Table 3.
  • the UE is configured with one CSI-RS resource with CSI-RS ports that are distributed across all RRHs. In one example, the UE is configured with CSI-RS resources, where the -th CSI-RS resource with CSI-RS ports is associated with the -th RRH.
  • the antenna structure is the same at each RRH, i.e., for all . In one example, where is a parameter for -th RRH, assuming that the antenna structure can be different across RRHs, i.e., .
  • the CSI-RS port numbering for D-MIMO is according to at least one of the following examples.
  • the CSI-RS ports are numbered in the following order: CSI-RS ports for RRH1, CSI-RS ports for RRH2 and so on.
  • the CSI-RS ports are numbered in the following order: CSI-RS ports with a first polarization for RRH1, CSI-RS ports with a second polarization for RRH1, CSI-RS ports with a first polarization for RRH2, CSI-RS ports with a second polarization for RRH2, and so on.
  • the CSI-RS ports are numbered in the following order: CSI-RS ports with a first polarization for RRH1, CSI-RS ports with a first polarization for RRH2, ..., CSI-RS ports with a second polarization for RRH1, CSI-RS ports with a second polarization for RRH2.
  • a first polarization refers to one first half (a first group) of the antenna ports with a first antenna polarization (e.g., +45), and a second polarization refers to one second half (a second group) of the antenna ports with a second antenna polarization (e.g., -45).
  • a UE is configured with a D-MIMO codebook (e.g., via higher layer signaling) which has a dual-stage pre-coder structure (for each layer), e.g., similar to (or based on) Rel. 15 NR Type II codebooks, or a triple-stage pre-coder structure (for each layer), e.g., similar to (or based on) Rel. 16 NR Type II codebooks.
  • the pre-coder for a layer can be represented as where the component is used to report/indicate a basis matrix comprising basis vectors, and the component is used to report/indicate one out of basis vector selection (for each layer), which is common for two polarizations, and a co-phase value for the two polarizations. Note that when , there is no need for any beam selection via .
  • the pre-coders for a layer can be represented as where the component is used to report/indicate a spatial domain (SD) basis matrix comprising SD basis vectors, the component is used to report/indicate a frequency domain (FD) basis matrix comprising FD basis vectors, and the component is used to report/indicate coefficients corresponding to SD and FD basis vector pairs.
  • SD spatial domain
  • FD frequency domain
  • FIGURE 13 illustrates an example D-MIMO 1300 where each RRH has a single antenna panel according to embodiments of the present disclosure.
  • the embodiment of the D-MIMO 1300 where each RRH has a single antenna panel illustrated in FIGURE 13 is for illustration only.
  • FIGURE 13 does not limit the scope of this disclosure to any particular implementation of the D-MIMO 1300 where each RRH has a single antenna panel.
  • each RRH has a single antenna panel.
  • the component has a block diagonal structure comprising diagonal blocks, where 1 (co-pol) or 2 (dual-pol) diagonal blocks are associated with each RRH.
  • RRH is a basis matrix for the 1 st RRH, and is a basis matrix for the 2 nd RRH.
  • RRH-common value for example, .
  • RRH-specific value for example, can take a value (fixed or configured) from ⁇ 1,4 ⁇ .
  • -th and -th diagonal blocks correspond to the two antenna polarizations for the -th RRH.
  • RRH-common value for example, .
  • RRH-specific value for example, can take a value (fixed or configured) from ⁇ 1,4 ⁇ .
  • -th and -th diagonal blocks correspond to the two antenna polarizations for the -th RRH.
  • RRH-common value for example, .
  • RRH-specific value for example, can take a value (fixed or configured) from ⁇ 1,4 ⁇ .
  • -th and -th diagonal blocks correspond to the two antenna polarizations for the -th RRH.
  • -th and -th diagonal blocks correspond to the two antenna polarizations for the -th RRH.
  • RRH-common and polarization-common value for example .
  • RRH-specific and polarization-common value for all values (RRH-common and polarization-common value).
  • RRH-common and polarization-specific value can be different across RRHs (RRH-specific and polarization-specific value).
  • -th and -th diagonal blocks correspond to the two antenna polarizations for the -th RRH.
  • -th and -th diagonal blocks correspond to the two antenna polarizations for the -th RRH.
  • RRH-common and polarization-common value for all and values (RRH-common and polarization-common value) , for example .
  • RRH-specific and polarization-common value for all values (RRH-common and polarization-common value).
  • RRH-common and polarization-specific value can be different across RRHs (RRH-specific and polarization-specific value).
  • FIGURE 14 illustrates an example D-MIMO 1400 where each RRH has multiple antenna panels according to embodiments of the present disclosure.
  • the embodiment of the D-MIMO 1400 where each RRH has multiple antenna panels illustrated in FIGURE 14 is for illustration only.
  • FIGURE 14 does not limit the scope of this disclosure to any particular implementation of the D-MIMO 1400 where each RRH has multiple antenna panels.
  • each RRH has multiple antenna panels.
  • the component has a block diagonal structure comprising diagonal blocks, where (co-pol) or (dual-pol) diagonal blocks are associated with -th RRH comprising panels and for all values of . Note for both RRHs in FIGURE 14.
  • FIGURE 15 illustrates an example D-MIMO 1500 where each RRH can have a single antenna panel or multiple antenna panels according to embodiments of the present disclosure.
  • the embodiment of the D-MIMO 1500 where each RRH can have a single antenna panel or multiple antenna panels illustrated in FIGURE 15 is for illustration only.
  • FIGURE 15 does not limit the scope of this disclosure to any particular implementation of the D-MIMO 1500 where each RRH can have a single antenna panel or multiple antenna panels.
  • each RRH can have a single antenna panel or multiple antenna panels.
  • the component has a block diagonal structure comprising diagonal blocks, where (co-pol) or (dual-pol) diagonal blocks are associated with -th RRH comprising panels, and when -th RRH has a single panel and when -th RRH has multiple panels.
  • the basis matrices comprising the diagonal blocks of the component have columns that are selected from a set of oversampled 2D DFT vectors.
  • a DFT vector can be expressed as follows.
  • a DFT vector can be expressed as follows.
  • the oversampling factor is RRH-common, hence remains the same across RRHs.
  • the oversampling factor is RRH-specific, hence is independent for each RRH.
  • RRH-common hence remains the same across RRHs.
  • the oversampling factor is RRH-specific, hence is independent for each RRH.
  • RRH-specific hence is independent for each RRH.
  • RRH and is chosen (fixed or configured) from ⁇ 2,4,8 ⁇ .
  • the oversampling factor is fixed, e.g., for low-resolution (Type I) codebook and for high-resolution (Type II) codebook.
  • the oversampling factor is configured, e.g., via RRC, where the configured value(s) is common for all RRHs, or independent for each RRH (i.e., one value is configured for each RRH).
  • each RRH can have a single antenna panel or multiple antenna panels (cf. FIGURE 15).
  • the component has a block diagonal structure comprising diagonal blocks, where (co-pol) or (dual-pol) diagonal blocks are associated with -th RRH comprising panels, and when -th RRH has a single panel and when -th RRH has multiple panels.
  • the codebook includes additional components due to RRHs.
  • the additional components include inter-RRH phase.
  • the inter-RRH phase values correspond to phase values.
  • the inter-RRH phase values can be quantized/reported as scalars using a scalar codebook (e.g., QPSK, 2 bits per phase or 8PSK, 3 bits per phase) or as a vector using a vector codebook (e.g., a DFT codebook).
  • the inter-RRH phase can be the same for two polarizations of the RRH. Alternatively, it can be independent for two polarizations for the RRH. At least one of the following example is used for the inter-RRH phase reporting.
  • the inter-RRH phase is reported in a wideband (WB) manner, i.e., one value is reported for all SBs in the configured CSI reporting band. Due to WB reporting, it can be included in the component of the codebook. Alternatively, it can be included in a new component, say of the codebook.
  • WB wideband
  • the inter-RRH phase is reported in a subband (SB) manner, i.e., one value is reported for each SB in the configured CSI reporting band. Due to SB reporting, it can be included in the component of the codebook. Alternatively, it can be included in a new component, say of the codebook.
  • SB subband
  • the inter-RRH phase is reported in a WB plus SB manner, i.e., one WB phase value is reported for all SBs in the configured CSI reporting band, and one SB value is reported for each SB in the configured CSI reporting band.
  • the WB part can be included in the component of the codebook and the SB part can be included in the component of the codebook.
  • both WB and SB parts can be included in a new component, say of the codebook.
  • the additional components include inter-RRH phase and inter-RRH amplitude, wherein the details about the inter-RRH phase are as explained in example III.1.1.
  • inter-RRH amplitude is needed due to unequal distance of the UE from RRHs.
  • the inter-RRH amplitude values correspond to amplitude values.
  • the inter-RRH amplitude values can be quantized/reported as scalars using a scalar codebook (e.g., 2 bits per amplitude or 3 bits per amplitude) or as a vector using a vector codebook.
  • a scalar codebook e.g., 2 bits per amplitude or 3 bits per amplitude
  • the inter-RRH amplitude can be the same for two polarizations of the RRH. Alternatively, it can be independent for two polarizations for the RRH. At least one of the following example is used for the inter-RRH amplitude and phase reporting.
  • the inter-RRH amplitude is reported in a wideband (WB) manner, i.e., one value is reported for all SBs in the configured CSI reporting band. Due to WB reporting, it can be included in the component of the codebook. Alternatively, it can be included in a new component, say of the codebook. At least one of the following example is used for the inter-RRH phase.
  • WB wideband
  • the inter-RRH amplitude is reported in a subband (SB) manner, i.e., one value is reported for each SB in the configured CSI reporting band. Due to SB reporting, it can be included in the component of the codebook. Alternatively, it can be included in a new component, say of the codebook. At least one of the following example is used for the inter-RRH phase.
  • SB subband
  • the inter-RRH amplitude is reported in a WB plus SB manner, i.e., one WB amplitude value is reported for all SBs in the configured CSI reporting band, and one SB value is reported for each SB in the configured CSI reporting band. Due to WB plus SB reporting, the WB part can be included in the component of the codebook and the SB part can be included in the component of the codebook. Alternatively, both WB and SB parts can be included in a new component, say of the codebook. At least one of the following example is used for the inter-RRH phase.
  • the additional components include inter-RRH amplitude, wherein the details about the inter-RRH amplitude are as explained in example III.1.2.
  • the additional components include inter-RRH power, wherein the details about the inter-RRH power are as explained in example III.1.2 by replacing amplitude with power.
  • a square of inter-RRH amplitude equals inter-RRH power.
  • the additional components include inter-RRH phase and inter-RRH power, wherein the details about the inter-RRH phase are as explained in example III.1.1, and the details about the inter-RRH power are as explained in example III.1.2 by replacing amplitude with power.
  • a square of inter-RRH amplitude equals inter-RRH power.
  • the additional components include an indicator indicating the strongest RRH (for reference). Due to distributed architecture, the strongest RRH can be reported in order to indicate the reference RRH with respect to which the inter-RRH components (such as amplitude or/and phase) are reported.
  • the inter-RRH amplitude and phase associated with the strongest RRH can be set to a fixed value, for example 1. At least one of the following example is used for the strongest RRH reporting.
  • the strongest RRH (indicator) is reported in a WB manner, i.e., one value (indicator) is reported for all SBs. Due to WB reporting, it can be included in the component of the codebook. Alternatively, it can be included in a new component, say of the codebook.
  • the strongest RRH (indicator) is reported in a SB manner, i.e., one value (indicator) is reported for each SB. Due to SB reporting, it can be included in the component of the codebook. Alternatively, it can be included in a new component, say of the codebook.
  • the strongest RRH is reported in a layer-common manner, i.e., one strongest RRH is reported common for all layers when number of layers > 1 (or rank > 1).
  • the strongest RRH is reported in a layer-specific manner, i.e., one strongest RRH is reported for each layer of the number of layers when number of layers > 1 (or rank > 1).
  • the amplitude/phase associated with the strongest RRH can be fixed, e.g., to 1.
  • the strongest RRH can be configured (e.g., via RRC signaling, or indicated via MAC CE or DCI or a combination of two or more of RRC, MAC CE and DCI), or can be fixed (e.g., RRH 1 is always strongest)
  • an RRH selection is performed wherein a subset of RRHs are selected from the RRHs and the CSI is reported for the selected RRHs.
  • the RRH selection is configured via RRC signaling, or indicated via MAC CE or DCI or a combination of two or more of RRC, MAC CE and DCI.
  • the RRH selection is performed in a layer-common manner, i.e., the RRH selection is performed common for all layers when number of layers > 1 (or rank > 1).
  • the RRH selection is performed in a layer-specific manner, i.e., the RRH selection is performed for each layer of the number of layers when number of layers > 1 (or rank > 1).
  • the codebook includes a component for RRH selection (ON/OFF).
  • this component is separate (dedicated for RRH selection).
  • a bit sequence comprising bits is used where each bit of the bit sequence is associated with an RRH, and the bit value '1' is used to indicate that the RRH is selected and the bit value '0' is used to indicate that the RRH is not selected.
  • a combinatorial index indicated via bits signaling, is used to indicate RRH selection hypotheses, W1 basis vector selection in Rel. 15 NR Type I codebook.
  • this component is combined (joint) with an amplitude component of the codebook, where the amplitude codebook includes a value 0 (in addition to other values greater than 0), and the value '0' is used to indicate/report that the RRH is not selected and the bit value greater than 0 is used to indicate/report that the RRH is selected and the indicated/reported value indicates the amplitude weighting in the precoder equation/calculation.
  • the codebook includes a component for RRH selection (ON/OFF).
  • this component is separate (dedicated for RRH selection).
  • a bit sequence comprising bits is used where each bit of the bit sequence is associated with an RRH, and the bit value '1' is used to indicate that the RRH is selected and the bit value '0' is used to indicate that the RRH is not selected.
  • a combinatorial index indicated via bits signaling, is used to indicate RRH selection hypotheses, W1 basis vector selection in Rel. 15 NR Type I codebook.
  • this component is combined (joint) with an amplitude component of the codebook, where the amplitude codebook includes a value 0 (in addition to other values greater than 0), and the value '0' is used to indicate/report that the RRH is not selected and the bit value greater than 0 is used to indicate/report that the RRH is selected and the indicated/reported value indicates the amplitude weighting in the precoder equation/calculation.
  • a UE is configured to report the CSI based on the D-MIMO codebook using a two-part UCI, UCI part 1 and UCI part 2, and the UCI part 1 is used indicate/report the RRH selection.
  • the two-part UCI is configured only when the UE is configured to report the SB CSI reporting based on the D-MIMO codebook.
  • the two-part UCI is configured only when the UE is configured with the Type II or Type II port selection codebook for D-MIMO.
  • a UE is configured to report the CSI based on the D-MIMO codebook using a two-part UCI, UCI part 1 and UCI part 2, and the UCI part 2 is used indicate/report the RRH selection.
  • the two-part UCI is configured only when the UE is configured to report the SB CSI reporting based on the D-MIMO codebook.
  • the two-part UCI is configured only when the UE is configured with the Type II or Type II port selection codebook for D-MIMO.
  • a UE is configured to report the CSI based on the D-MIMO codebook using one-part UCI, which is used indicate/report the RRH selection.
  • the one-part UCI is configured only when the UE is configured to report the WB CSI reporting based on the D-MIMO codebook.
  • the one-part UCI is configured only when the UE is configured with the Type I codebook for D-MIMO.
  • a UE is configured with a two-part UCI (part 1 and part 2) for CSI reporting based on D-MIMO codebook.
  • UCI part 1 includes the information about the RRH selection.
  • UCI part 1 includes the information the strongest RRH.
  • UCI part 1 includes both the information the strongest RRH and the information about the RRH selection.
  • UCI part 2 includes the information about the RRH selection.
  • UCI part 2 includes the information the strongest RRH.
  • UCI part 2 includes both the information the strongest RRH and the information about the RRH selection.
  • a UE is configured with a one-part UCI for RRH selection reporting.
  • this configuration is restricted to the case when WB CSI reporting is configured (i.e., for SB CSI reporting, two-part UCI is used to report RRH selection).
  • this configuration is restricted to the case when Type I codebook for D-MIMO is configured (i.e., for Type II codebook, two-part UCI is used to report RRH selection).
  • a UE is configured with a one-part UCI for the strongest RRH reporting.
  • this configuration is restricted to the case when WB CSI reporting is configured (i.e., for SB CSI reporting, two-part UCI is used to report RRH selection).
  • this configuration is restricted to the case when Type I codebook for D-MIMO is configured (i.e., for Type II codebook, two-part UCI is used to report RRH selection).
  • a UE is configured with a one-part UCI for both RRH selection and the strongest RRH reporting.
  • this configuration is restricted to the case when WB CSI reporting is configured (i.e., for SB CSI reporting, two-part UCI is used to report RRH selection).
  • this configuration is restricted to the case when Type I codebook for D-MIMO is configured (i.e., for Type II codebook, two-part UCI is used to report RRH selection).
  • the parameter is fixed, e.g., 2.
  • the parameter is configured, e.g., via RRC.
  • the parameter is reported by the UE, e.g., via UCI part 1 of two-part UCI comprising part 1 and part 2.
  • the reported value can be based on a minimum value , i.e., the UE can report any such that .
  • the reported value can be based on a maximum value , i.e., the UE can report any such that .
  • the reported value can be based on a minimum value and a maximum value , i.e., the UE can report any such that .
  • the value or/and can be fixed, or configured (e.g., RRC) or reported by the UE as part of UE capability reporting.
  • both and indicator indicating selected RRHs are reported via UCI part 1.
  • UCI part 1 is reported via UCI part 1
  • indicator indicating selected RRHs is reported via UCI part 2.
  • the codebook component refers to pre-coder (or pre-coding matrix) components that are indicated via the components of the first PMI indicator .
  • the codebook component refers to pre-coder (or pre-coding matrix) components that are indicated via the components of the second PMI indicator .
  • the new codebook component refers to pre-coder (or pre-coding matrix) components that are indicated via the components of the third PMI indicator .
  • the codebook for D-MIMO transmission has one of the fowling designs.
  • the codebook has a decoupled (separate) design for inter-RRH and intra-RRH components.
  • (Inter-RRH, Intra-RRH) (Type I, Type I) or (Type II, Type I) or (Type I, Type II), or (Type II, Type II), wherein the Type I implies that the corresponding codebook components has similarity with Rel. 15 NR Type I codebook, and likewise, Type II implies that the corresponding codebook components has similarity with Rel. 15 or 16 NR Type II codebook.
  • the codebook has a coupled (joint) design for inter-RRH and intra-RRH components.
  • (Inter-RRH, Intra-RRH) has a Type I or Type II like design.
  • the components have one of the following high-level design.
  • the components have Type I structure.
  • only or is used in i.e., only one beam or basis vector is used for each layer (or precoder for each layer).
  • or (e.g., 4) is used in , i.e., multiple beams or basis vectors are included in , but the UE selects one beam or basis vector out of beams for each layer (or precoder for each layer).
  • the UE is configured with either or in , and the UE selects/reports accordingly.
  • o Multi-panel at least two or all of cross-pol co-phase, inter-panel phase, inter-RRH phase are joint
  • the components has Type II structure.
  • the value of is configured (e.g., via RRC signaling) from a set of supported values.
  • the set of supported values belongs to .
  • the D-MIMO codebook includes both coherent and non-coherent pre-coders, wherein a coherent pre-coder corresponds to a precoder or pre-coding matrix whose all entries all non-zero, and a non-coherent pre-coder corresponds to a precoder or pre-coding matrix who's each row or each column has at least one zero entry.
  • FIGURE 16 illustrates a flow chart of a method 1600 for operating a user equipment (UE), as may be performed by a UE such as UE 116, according to embodiments of the present disclosure.
  • the embodiment of the method 1600 illustrated in FIGURE 16 is for illustration only.
  • FIGURE 18 does not limit the scope of this disclosure to any particular implementation.
  • the method 1600 begins at step 1602.
  • the UE e.g., 111-116 as illustrated in FIGURE 1
  • CSI channel state information
  • step 1604 the UE selects a strongest RRH from the RRHs.
  • step 1606 the UE determines the CSI report including an indicator indicating the strongest RRH.
  • step 1608 the UE transmits the CSI report including the indicator indicating the strongest RRH.
  • the information includes an information about .
  • the strongest RRH is reported as either wideband (WB) or subband (SB), where WB corresponds to a single value that is common for all subbands in a CSI reporting band and SB corresponds to multiple values, one value for each subband in the CSI reporting band.
  • WB wideband
  • SB subband
  • the strongest RRH is reported as either layer-common or layer-specific, where the layer-common corresponds to a single value that is common for all layers and the layer-specific corresponds to multiple values, one value for each layer.
  • an amplitude associated with the strongest RRH 1.
  • the UE determines the CSI report including an indicator indicating an RRH selection in which out of the RRHs are selected, wherein the CSI report is determined for the selected out of the RRHs, and .
  • the indicator indicating the RRH selection is a bit sequence of length , where indicates RRH not selected, and indicates RRH being selected.
  • the indicator indicating the RRH selection is a bit combinatorial indicator, wherein is a ceiling function.
  • the indicator indicating the RRH selection indicates an amplitude value ( ) for each RRH, where indicates that RRH is not selected, and indicates that RRH is selected.
  • the RRH selection is reported as either layer-common or layer-specific, where the layer-common corresponds to a single value that is common for all layers and the layer-specific corresponds to multiple values, one value for each layer.
  • the UE transmits the CSI report via a two-part uplink control information (UCI) comprising part 1 and part 2, and UCI part 1 includes information about the RRH selection.
  • UCI uplink control information
  • FIGURE 17 illustrates a flow chart of another method 1700, as may be performed by a base station (BS) such as BS 102, according to embodiments of the present disclosure.
  • BS base station
  • the embodiment of the method 1700 illustrated in FIGURE 17 is for illustration only.
  • FIGURE 17 does not limit the scope of this disclosure to any particular implementation.
  • the method 1700 begins at step 1702.
  • the BS e.g., 101-103 as illustrated in FIGURE 1
  • CSI channel state information
  • step 1704 the BS transmits the information.
  • the BS receives the CSI report, wherein the CSI report includes an indicator indicating a strongest RRH selected from the RRHs.
  • the information includes an information about .
  • the strongest RRH is reported as either wideband (WB) or subband (SB), where WB corresponds to a single value that is common for all subbands in a CSI reporting band and SB corresponds to multiple values, one value for each subband in the CSI reporting band.
  • WB wideband
  • SB subband

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Abstract

The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The present disclosure relates to channel state information (CSI) reporting based on a codebook for distributed MIMO transmission.

Description

CODEBOOK FOR DISTRIBUTED MIMO TRANSMISSION
The present disclosure relates generally to wireless communication systems and more specifically to CSI reporting based on a codebook for distributed MIMO transmission.
To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a 'Beyond 4G Network' or a 'Post LTE System'. The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems. In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like. In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access(NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of the IoT technology and the Big Data processing technology through connection with a cloud server, has emerged. As technology elements, such as "sensing technology", "wired/wireless communication and network infrastructure", "service interface technology", and "Security technology" have been demanded for IoT implementation, a sensor network, a Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and so forth have been recently researched. Such an IoT environment may provide intelligent Internet technology services that create a new value to human life by collecting and analyzing data generated among connected things. IoT may be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances and advanced medical services through convergence and combination between existing Information Technology (IT) and various industrial applications.
In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as a sensor network, Machine Type Communication (MTC), and Machine-to-Machine (M2M) communication may be implemented by beamforming, MIMO, and array antennas. Application of a cloud Radio Access Network (RAN) as the above-described Big Data processing technology may also be considered to be as an example of convergence between the 5G technology and the IoT technology.
Understanding and correctly estimating the channel between a user equipment (UE) and a base station (BS) (e.g., gNode B (gNB)) is important for efficient and effective wireless communication. In order to correctly estimate the DL channel conditions, the gNB may transmit a reference signal, e.g., CSI-RS, to the UE for DL channel measurement, and the UE may report (e.g., feedback) information about channel measurement, e.g., CSI, to the gNB. With this DL channel measurement, the gNB is able to select appropriate communication parameters to efficiently and effectively perform wireless data communication with the UE.
There is a need to design codebooks for distributed MIMO antenna structure for efficient and effective wireless communication.
Embodiments of the present disclosure provide methods and apparatuses to enable channel state information (CSI) reporting based on a codebook for distributed MIMO transmission in a wireless communication system.
In one embodiment, a UE for CSI reporting in a wireless communication system is provided. The UE includes a transceiver configured to receive information about a channel state information (CSI) report, the information including a number
Figure PCTKR2021018843-appb-I000001
> 1 and RRH
Figure PCTKR2021018843-appb-I000002
, wherein:
Figure PCTKR2021018843-appb-I000003
=number of remote radio heads (RRHs), RRH
Figure PCTKR2021018843-appb-I000004
comprises a group of
Figure PCTKR2021018843-appb-I000005
channel state information reference signal (CSIRS) antenna ports, and r = 1, . . . ,
Figure PCTKR2021018843-appb-I000006
. The UE further includes a processor operably connected to the transceiver. The processor, based on the information, is configured to: select a strongest RRH from the
Figure PCTKR2021018843-appb-I000007
RRHs; and determine the CSI report including an indicator indicating the strongest RRH. The transceiver is further configured to transmit the CSI report including the indicator indicating the strongest RRH.
In another embodiment, a BS in a wireless communication system is provided. The BS includes a processor configured to generate information about a channel state information (CSI) report, the information including a number
Figure PCTKR2021018843-appb-I000008
> 1 and RRH
Figure PCTKR2021018843-appb-I000009
, wherein:
Figure PCTKR2021018843-appb-I000010
= number of remote radio heads (RRHs), RRH
Figure PCTKR2021018843-appb-I000011
comprises a group of
Figure PCTKR2021018843-appb-I000012
channel state information reference signal (CSIRS) antenna ports, and r = 1, . . . ,
Figure PCTKR2021018843-appb-I000013
. The BS further includes a transceiver operably connected to the processor. The transceiver is configured to: transmit the information; and receive the CSI report, wherein the CSI report includes an indicator indicating a strongest RRH selected from the
Figure PCTKR2021018843-appb-I000014
RRHs.
In yet another embodiment, a method for operating a UE is provided. The method comprises: receiving information about a channel state information (CSI) report, the information including a number
Figure PCTKR2021018843-appb-I000015
> 1 and RRH
Figure PCTKR2021018843-appb-I000016
, wherein:
Figure PCTKR2021018843-appb-I000017
=number of remote radio heads (RRHs), RRH
Figure PCTKR2021018843-appb-I000018
comprises a group of
Figure PCTKR2021018843-appb-I000019
channel state information reference signal (CSIRS) antenna ports, and r = 1, . . . ,
Figure PCTKR2021018843-appb-I000020
; selecting a strongest RRH from the
Figure PCTKR2021018843-appb-I000021
RRHs; determining the CSI report including an indicator indicating the strongest RRH; and transmitting the CSI report including the indicator indicating the strongest RRH.
Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.
According to the present disclosure, several codebook design alternatives for D-MIMO antenna structure for efficient and effective wireless communication is provided.
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 represent like parts:
FIGURE 1 illustrates an example wireless network according to embodiments of the present disclosure;
FIGURE 2 illustrates an example gNB according to embodiments of the present disclosure;
FIGURE 3 illustrates an example UE according to embodiments of the present disclosure;
FIGURE 4A illustrates a high-level diagram of an orthogonal frequency division multiple access transmit path according to embodiments of the present disclosure;
FIGURE 4B illustrates a high-level diagram of an orthogonal frequency division multiple access receive path according to embodiments of the present disclosure;
FIGURE 5 illustrates a transmitter block diagram for a PDSCH in a subframe according to embodiments of the present disclosure;
FIGURE 6 illustrates a receiver block diagram for a PDSCH in a subframe according to embodiments of the present disclosure;
FIGURE 7 illustrates a transmitter block diagram for a PUSCH in a subframe according to embodiments of the present disclosure;
FIGURE 8 illustrates a receiver block diagram for a PUSCH in a subframe according to embodiments of the present disclosure;
FIGURE 9 illustrates an example antenna blocks or arrays forming beams according to embodiments of the present disclosure;
FIGURE 10 illustrates an example distributed MIMO (D-MIMO) system according to embodiments of the present disclosure;
FIGURE 11 illustrates an example antenna port layout according to embodiments of the present disclosure;
FIGURE 12 illustrates an example of Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission according to embodiments of the present disclosure;
FIGURE 13 illustrates an example D-MIMO where each RRH has a single antenna panel according to embodiments of the present disclosure;
FIGURE 14 illustrates an example D-MIMO where each RRH has multiple antenna panels according to embodiments of the present disclosure;
FIGURE 15 illustrates an example D-MIMO where each RRH can have a single antenna panel or multiple antenna panels according to embodiments of the present disclosure;
FIGURE 16 illustrates a flow chart of a method for operating a UE according to embodiments of the present disclosure; and
FIGURE 17 illustrates a flow chart of a method for operating a BS according to embodiments of the present disclosure.
Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term "couple" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms "transmit," "receive," and "communicate," as well as derivatives thereof, encompass both direct and indirect communication. The terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation. The term "or" is inclusive, meaning and/or. The phrase "associated with," as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term "controller" means any 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 any particular controller may be centralized or distributed, whether locally or remotely. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, "at least one of: A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.
Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from 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, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A "non-transitory" computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.
Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.
FIGURES 1 through FIGURE 17, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.
The following documents and standards descriptions are hereby incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 36.211 v16.6.0, "E-UTRA, Physical channels and modulation" (herein "REF 1"); 3GPP TS 36.212 v16.6.0, "E-UTRA, Multiplexing and Channel coding" (herein "REF 2"); 3GPP TS 36.213 v16.6.0, "E-UTRA, Physical Layer Procedures" (herein "REF 3"); 3GPP TS 36.321 v16.6.0, "E-UTRA, Medium Access Control (MAC) protocol specification" (herein "REF 4"); 3GPP TS 36.331 v16.6.0, "E-UTRA, Radio Resource Control (RRC) protocol specification" (herein "REF 5"); 3GPP TR 22.891 v14.2.0 (herein "REF 6"); 3GPP TS 38.212 v16.6.0, "E-UTRA, NR, Multiplexing and channel coding" (herein "REF 7"); and 3GPP TS 38.214 v16.6.0, "E-UTRA, NR, Physical layer procedures for data" (herein "REF 8").
Aspects, features, and advantages of the disclosure are readily apparent from the following detailed description, simply by illustrating a number of particular embodiments and implementations, including the best mode contemplated for carrying out the disclosure. The disclosure is also capable of other and different embodiments, and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. The disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.
In the following, for brevity, both FDD and TDD are considered as the duplex method for both DL and UL signaling.
Although exemplary descriptions and embodiments to follow assume orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA), the present disclosure can be extended to other OFDM-based transmission waveforms or multiple access schemes such as filtered OFDM (F-OFDM).
To meet the demand for wireless data traffic having increased since deployment of 4G communication systems and to enable various vertical applications, 5G/NR communication systems have been developed and are currently being deployed. The 5G/NR communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60GHz bands, so as to accomplish higher data rates or in lower frequency bands, such as 6 GHz, to enable robust coverage and mobility support. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G/NR communication systems.
In addition, in 5G/NR communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation and the like.
The discussion of 5G systems and frequency bands associated therewith is for reference as certain embodiments of the present disclosure may be implemented in 5G systems.  However, the present disclosure is not limited to 5G systems or the frequency bands associated therewith, and embodiments of the present disclosure may be utilized in connection with any frequency band. For example, aspects of the present disclosure may also be applied to deployment of 5G communication systems, 6G or even later releases which may use terahertz (THz) bands.
FIGURES 1-4B below describe various embodiments implemented in wireless communications systems and with the use of orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication techniques. The descriptions of FIGURES 1-3 are not meant to imply physical or architectural limitations to the manner in which different embodiments may be implemented. Different embodiments of the present disclosure may be implemented in any suitably-arranged communications system. The present disclosure covers several components which can be used in conjunction or in combination with one another, or can operate as standalone schemes.
FIGURE 1 illustrates an example wireless network according to embodiments of the present disclosure. The embodiment of the wireless network shown in FIGURE 1 is for illustration only. Other embodiments of the wireless network 100 could be used without departing from the scope of this disclosure.
As shown in FIGURE 1, the wireless network includes a gNB 101, a gNB 102, and a gNB 103. The gNB 101 communicates with the gNB 102 and the gNB 103. The gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.
The gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipments (UEs) within a coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111, which may be located in a small business; a UE 112, which may be located in an enterprise (E); a UE 113, which may be located in a WiFi hotspot (HS); a UE 114, which may be located in a first residence (R); a UE 115, which may be located in a second residence (R); and a UE 116, which may be a mobile device (M), such as a cell phone, a wireless laptop, a wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more of the gNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G, LTE, LTE-A, WiMAX, WiFi, or other wireless communication techniques.
Depending on the network type, the term "base station" or "BS" can refer to any component (or collection of components) configured to provide wireless access to a network, such as transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., 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 the sake of convenience, the terms "BS" and "TRP" are used interchangeably in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, the term "user equipment" or "UE" can refer to any component such as "mobile station," "subscriber station," "remote terminal," "wireless terminal," "receive point," or "user device." For the sake of convenience, the terms "user equipment" and "UE" are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).
Dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending upon the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.
As described in more detail below, one or more of the UEs 111-116 include circuitry, programing, or a combination thereof, for receiving information about a channel state information (CSI) report, the information including a number
Figure PCTKR2021018843-appb-I000022
> 1 and RRH
Figure PCTKR2021018843-appb-I000023
, wherein:
Figure PCTKR2021018843-appb-I000024
=number of remote radio heads (RRHs), RRH
Figure PCTKR2021018843-appb-I000025
comprises a group of
Figure PCTKR2021018843-appb-I000026
channel state information reference signal (CSIRS) antenna ports, and r = 1, . . . ,
Figure PCTKR2021018843-appb-I000027
; selecting a strongest RRH from the
Figure PCTKR2021018843-appb-I000028
RRHs; determining the CSI report including an indicator indicating the strongest RRH; and transmitting the CSI report including the indicator indicating the strongest RRH. One or more of the gNBs 101-103 includes circuitry, programing, or a combination thereof, for generating information about a channel state information (CSI) report, the information including a number
Figure PCTKR2021018843-appb-I000029
> 1 and RRH
Figure PCTKR2021018843-appb-I000030
, wherein:
Figure PCTKR2021018843-appb-I000031
= number of remote radio heads (RRHs), RRH
Figure PCTKR2021018843-appb-I000032
comprises a group of
Figure PCTKR2021018843-appb-I000033
channel state information reference signal (CSIRS) antenna ports, and r = 1, . . . ,
Figure PCTKR2021018843-appb-I000034
; transmitting the information; and receiving the CSI report, wherein the CSI report includes an indicator indicating a strongest RRH selected from the
Figure PCTKR2021018843-appb-I000035
RRHs.
Although FIGURE 1 illustrates one example of a wireless network, various changes may be made to FIGURE 1. For example, the wireless network could include any number of gNBs and any number of UEs in any suitable arrangement. Also, the gNB 101 could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network 130. Similarly, each gNB 102-103 could communicate directly with the network 130 and provide UEs with direct wireless broadband access to the network 130. Further, the gNBs 101, 102, and/or 103 could provide access to other or additional external networks, such as external telephone networks or other types of data networks.
FIGURE 2 illustrates an example gNB 102 according to embodiments of the present disclosure. The embodiment of the gNB 102 illustrated in FIGURE 2 is for illustration only, and the gNBs 101 and 103 of FIGURE 1 could have the same or similar configuration. However, gNBs come in a wide variety of configurations, and FIGURE 2 does not limit the scope of this disclosure to any particular implementation of a gNB.
As shown in FIGURE 2, the gNB 102 includes multiple antennas 205a-205n, multiple RF transceivers 210a-210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. The gNB 102 also includes a controller/processor 225, a memory 230, and a backhaul or network interface 235.
The RF transceivers 210a-210n receive, from the antennas 205a-205n, incoming RF signals, such as signals transmitted by UEs in 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 sent to the RX processing circuitry 220, which generates processed baseband signals by filtering, decoding, and/or digitizing the baseband or IF signals. The RX processing circuitry 220 transmits the processed baseband signals to the controller/processor 225 for further processing.
The TX processing circuitry 215 receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor 225. The TX processing circuitry 215 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals. The RF transceivers 210a-210n receive the outgoing processed baseband or IF signals from the TX processing circuitry 215 and up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 205a-205n.
The controller/processor 225 can include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller/processor 225 could control the reception of UL channel signals and the transmission of DL channel signals by the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 in accordance with well-known principles. The controller/processor 225 could support additional functions as well, such as more advanced wireless communication functions.
For instance, the controller/processor 225 could support beam forming or directional routing operations in which outgoing signals from multiple antennas 205a-205n are weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions could be supported in the gNB 102 by the controller/processor 225.
The controller/processor 225 is also capable of executing programs and other processes resident in the memory 230, such as an OS. The controller/processor 225 can move data into or out of the memory 230 as required by an executing process.
The controller/processor 225 is also coupled to the backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 235 could support communications over any suitable wired or wireless connection(s). For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G, LTE, or LTE-A), the interface 235 could allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 could allow the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface 235 includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or RF transceiver.
The memory 230 is coupled to the controller/processor 225. Part of the memory 230 could include a RAM, and another part of the memory 230 could include a Flash memory or other ROM.
Although FIGURE 2 illustrates one example of gNB 102, various changes may be made to FIGURE 2. For example, the gNB 102 could include any number of each component shown in FIGURE 2. As a particular example, an access point could include a number of interfaces 235, and the controller/processor 225 could support routing functions to route data between different network addresses. As another particular example, while shown as including a single instance of TX processing circuitry 215 and a single instance of RX processing circuitry 220, the gNB 102 could include multiple instances of each (such as one per RF transceiver). Also, various components in FIGURE 2 could be combined, further subdivided, or omitted and additional components could be added according to particular needs.
FIGURE 3 illustrates an example UE 116 according to embodiments of the present disclosure. The embodiment of the UE 116 illustrated in FIGURE 3 is for illustration only, and the UEs 111-115 of FIGURE 1 could have the same or similar configuration. However, UEs come in a wide variety of configurations, and FIGURE 3 does not limit the scope of this disclosure to any particular implementation of a UE.
As shown in FIGURE 3, the UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, TX processing circuitry 315, a microphone 320, and receive (RX) processing circuitry 325. The UE 116 also 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 operating system (OS) 361 and one or more applications 362.
The RF transceiver 310 receives, from the antenna 305, an incoming RF signal transmitted by a gNB of the network 100. The RF transceiver 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is sent 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 (such as for voice data) or to the processor 340 for further processing (such as for web browsing data).
The TX processing circuitry 315 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor 340. The TX processing circuitry 315 encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 310 receives the outgoing processed baseband or IF signal from the TX processing circuitry 315 and up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna 305.
The processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116. For example, the processor 340 could control the reception of DL channel signals and the transmission of UL channel signals by the RF transceiver 310, the RX processing circuitry 325, and the TX processing circuitry 315 in accordance with well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.
The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as processes for receiving information about a channel state information (CSI) report, the information including a number
Figure PCTKR2021018843-appb-I000036
> 1 and RRH
Figure PCTKR2021018843-appb-I000037
, wherein:
Figure PCTKR2021018843-appb-I000038
=number of remote radio heads (RRHs), RRH
Figure PCTKR2021018843-appb-I000039
comprises a group of
Figure PCTKR2021018843-appb-I000040
channel state information reference signal (CSIRS) antenna ports, and r = 1, . . . ,
Figure PCTKR2021018843-appb-I000041
; selecting a strongest RRH from the
Figure PCTKR2021018843-appb-I000042
RRHs; determining the CSI report including an indicator indicating the strongest RRH; and transmitting the CSI report including the indicator indicating the strongest RRH. The processor 340 can move data into or out of the memory 360 as required by an executing process. In some embodiments, the processor 340 is configured to execute the applications 362 based on the OS 361 or in response to signals received from gNBs or an operator. The processor 340 is also coupled to the I/O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. The I/O interface 345 is the communication path between these accessories and the processor 340.
The processor 340 is also coupled to the touchscreen 350 and the display 355. The operator of the UE 116 can use the touchscreen 350 to enter data into the UE 116. The display 355 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and/or at least limited graphics, such as from web sites.
The memory 360 is coupled to the processor 340. Part of the memory 360 could include a random access memory (RAM), and another part of the memory 360 could include a Flash memory or other read-only memory (ROM).
Although FIGURE 3 illustrates one example of UE 116, various changes may be made to FIGURE 3. For example, various components in FIGURE 3 could be combined, further subdivided, or omitted and additional components could be added according to particular needs. As a particular example, the processor 340 could 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 telephone or smartphone, UEs could be configured to operate as other types of mobile or stationary devices.
FIGURE 4A is a high-level diagram of transmit path circuitry. For example, the transmit path circuitry may be used for an orthogonal frequency division multiple access (OFDMA) communication. FIGURE 4B is a high-level diagram of receive path circuitry. For example, the receive path circuitry may be used for an orthogonal frequency division multiple access (OFDMA) communication. In FIGURES 4A and 4B, for downlink communication, the transmit path circuitry may be implemented in a base station (gNB) 102 or a relay station, and the receive path circuitry may be implemented in a user equipment (e.g., user equipment 116 of FIGURE 1). In other examples, for uplink communication, the receive path circuitry 450 may be implemented in a base station (e.g., gNB 102 of FIGURE 1) or a relay station, and the transmit path circuitry may be implemented in a user equipment (e.g., user equipment 116 of FIGURE 1).
Transmit path circuitry comprises channel coding and modulation block 405, serial-to-parallel (S-to-P) block 410, Size N Inverse Fast Fourier Transform (IFFT) block 415, parallel-to-serial (P-to-S) block 420, add cyclic prefix block 425, and up-converter (UC) 430. Receive path circuitry 450 comprises down-converter (DC) 455, remove cyclic prefix block 460, serial-to-parallel (S-to-P) block 465, Size N Fast Fourier Transform (FFT) block 470, parallel-to-serial (P-to-S) block 475, and channel decoding and demodulation block 480.
At least some of the components in FIGURES 4A 400 and 4B 450 may be implemented in software, while other components may be implemented by configurable hardware or a mixture of software and configurable hardware. In particular, it is noted that the FFT blocks and the IFFT blocks described in this disclosure document may be implemented as configurable software algorithms, where the value of Size N may be modified according to the implementation.
Furthermore, although this disclosure is directed to an embodiment that implements the Fast Fourier Transform and the Inverse Fast Fourier Transform, this is by way of illustration only and may not be construed to limit the scope of the disclosure. It may be appreciated that in an alternate embodiment of the present disclosure, the Fast Fourier Transform functions and the Inverse Fast Fourier Transform functions may easily be replaced by discrete Fourier transform (DFT) functions and inverse discrete Fourier transform (IDFT) functions, respectively. It may be appreciated that for DFT and IDFT functions, the value of the N variable may be any integer number (i.e., 1, 4, 3, 4, etc.), while for FFT and IFFT functions, the value of the N variable may be any integer number that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).
In transmit path circuitry 400, channel coding and modulation block 405 receives a set of information bits, applies coding (e.g., LDPC coding) and modulates (e.g., quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)) the input bits to produce a sequence of frequency-domain modulation symbols. Serial-to-parallel block 410 converts (i.e., de-multiplexes) the serial modulated symbols to parallel data to produce N parallel symbol streams where N is the IFFT/FFT size used in BS 102 and UE 116. Size N IFFT block 415 then performs an IFFT operation on the N parallel symbol streams to produce time-domain output signals. Parallel-to-serial block 420 converts (i.e., multiplexes) the parallel time-domain output symbols from Size N IFFT block 415 to produce a serial time-domain signal. Add cyclic prefix block 425 then inserts a cyclic prefix to the time-domain signal. Finally, up-converter 430 modulates (i.e., up-converts) the output of add cyclic prefix block 425 to RF frequency for transmission via a wireless channel. The signal may also be filtered at baseband before conversion to RF frequency.
The transmitted RF signal arrives at the UE 116 after passing through the wireless channel, and reverse operations to those at gNB 102 are performed. Down-converter 455 down-converts the received signal to baseband frequency and removes cyclic prefix block 460, and removes the cyclic prefix to produce the serial time-domain baseband signal. Serial-to-parallel block 465 converts the time-domain baseband signal to parallel time-domain signals. Size N FFT block 470 then performs an FFT algorithm to produce N parallel frequency-domain signals. Parallel-to-serial block 475 converts the parallel frequency-domain signals to a sequence of modulated data symbols. Channel decoding and demodulation block 480 demodulates and then decodes the modulated symbols to recover the original input data stream.
Each of gNBs 101-103 may implement a transmit path that is analogous to transmitting in the downlink to user equipment 111-116 and may implement a receive path that is analogous to receiving in the uplink from user equipment 111-116. Similarly, each one of user equipment 111-116 may implement a transmit path corresponding to the architecture for transmitting in the uplink to gNBs 101-103 and may implement a receive path corresponding to the architecture for receiving in the downlink from gNBs 101-103.
A communication system includes a downlink (DL) that conveys signals from transmission points such as base stations (BSs) or NodeBs to user equipments (UEs) and an Uplink (UL) that conveys signals from UEs to reception points such as NodeBs. A UE, also commonly referred to as a terminal or a mobile station, may be fixed or mobile and may be a cellular phone, a personal computer device, or an automated device. An eNodeB, which is generally a fixed station, may also be referred to as an access point or other equivalent terminology. For LTE systems, a NodeB is often referred as an eNodeB.
In a communication system, such as LTE system, DL signals can include data signals conveying information content, control signals conveying DL control information (DCI), and reference signals (RS) that are also known as pilot signals. An eNodeB transmits data information through a physical DL shared channel (PDSCH). An eNodeB transmits DCI through a physical DL control channel (PDCCH) or an Enhanced PDCCH (EPDCCH).
An eNodeB transmits acknowledgement information in response to data transport block (TB) transmission from a UE in a physical hybrid ARQ indicator channel (PHICH). An eNodeB transmits one or more of multiple types of RS including a UE-common RS (CRS), a channel state information RS (CSI-RS), or a demodulation RS (DMRS). A CRS is transmitted over a DL system bandwidth (BW) and can be used by UEs to obtain a channel estimate to demodulate data or control information or to perform measurements. To reduce CRS overhead, an eNodeB may transmit a CSI-RS with a smaller density in the time and/or frequency domain than a CRS. DMRS can be transmitted only in the BW of a respective PDSCH or EPDCCH and a UE can use the DMRS to demodulate data or control information in a PDSCH or an EPDCCH, respectively. A transmission time interval for DL channels is referred to as a subframe and can have, for example, duration of 1 millisecond.
DL signals also include transmission of a logical channel that carries system control information. A BCCH is mapped to either a transport channel referred to as a broadcast channel (BCH) when the DL signals convey a master information block (MIB) or to a DL shared channel (DL-SCH) when the DL signals convey a System Information Block (SIB). Most system information is included in different SIBs that are transmitted using DL-SCH. A presence of system information on a DL-SCH in a subframe can be indicated by a transmission of a corresponding PDCCH conveying a codeword with a cyclic redundancy check (CRC) scrambled with system information RNTI (SI-RNTI). Alternatively, scheduling information for a SIB transmission can be provided in an earlier SIB and scheduling information for the first SIB (SIB-1) can be provided by the MIB.
DL resource allocation is performed in a unit of subframe and a group of physical resource blocks (PRBs). A transmission BW includes frequency resource units referred to as resource blocks (RBs). Each RB includes
Figure PCTKR2021018843-appb-I000043
sub-carriers, or resource elements (REs), such as 12 REs. A unit of one RB over one subframe is referred to as a PRB. A UE can be allocated
Figure PCTKR2021018843-appb-I000044
RBs for a total of
Figure PCTKR2021018843-appb-I000045
REs for the PDSCH transmission BW.
UL signals can include data signals conveying data information, control signals conveying UL control information (UCI), and UL RS. UL RS includes DMRS and Sounding RS (SRS). A UE transmits DMRS only in a BW of a respective PUSCH or PUCCH. An eNodeB can use a DMRS to demodulate data signals or UCI signals. A UE transmits SRS to provide an eNodeB with an UL CSI. A UE transmits data information or UCI through a respective physical UL shared channel (PUSCH) or a Physical UL control channel (PUCCH). If a UE needs to transmit data information and UCI in a same UL subframe, the UE may multiplex both in a PUSCH. UCI includes Hybrid Automatic Repeat request acknowledgement (HARQ-ACK) information, indicating correct (ACK) or incorrect (NACK) detection for a data TB in a PDSCH or absence of a PDCCH detection (DTX), scheduling request (SR) indicating whether a UE has data in the UE's buffer, rank indicator (RI), and channel state information (CSI) enabling an eNodeB to perform link adaptation for PDSCH transmissions to a UE. HARQ-ACK information is also transmitted by a UE in response to a detection of a PDCCH/EPDCCH indicating a release of semi-persistently scheduled PDSCH.
An UL subframe (or slot) includes two slots. Each slot includes
Figure PCTKR2021018843-appb-I000046
symbols for transmitting data information, UCI, DMRS, or SRS. A frequency resource unit of an UL system BW is a RB. A UE is allocated
Figure PCTKR2021018843-appb-I000047
RBs for a total of
Figure PCTKR2021018843-appb-I000048
REs for a transmission BW. For a PUCCH,
Figure PCTKR2021018843-appb-I000049
. A last subframe symbol can be used to multiplex SRS transmissions from one or more UEs. A number of subframe symbols that are available for data/UCI/DMRS transmission is
Figure PCTKR2021018843-appb-I000050
, where
Figure PCTKR2021018843-appb-I000051
if a last subframe symbol is used to transmit SRS and
Figure PCTKR2021018843-appb-I000052
otherwise.
FIGURE 5 illustrates a transmitter block diagram 500 for a PDSCH in a subframe according to embodiments of the present disclosure. The embodiment of the transmitter block diagram 500 illustrated in FIGURE 5 is for illustration only. One or more of the components illustrated in FIGURE 5 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions. FIGURE 5 does not limit the scope of this disclosure to any particular implementation of the transmitter block diagram 500.
As shown in FIGURE 5, information bits 510 are encoded by encoder 520, such as a turbo encoder, and modulated by modulator 530, for example using quadrature phase shift keying (QPSK) modulation. A serial to parallel (S/P) converter 540 generates M modulation symbols that are subsequently provided to a mapper 550 to be mapped to REs selected by a transmission BW selection unit 555 for an assigned PDSCH transmission BW, unit 560 applies an Inverse fast Fourier transform (IFFT), the output is then serialized by a parallel to serial (P/S) converter 570 to create a time domain signal, filtering is applied by filter 580, and a signal transmitted 590. Additional functionalities, such as data scrambling, cyclic prefix insertion, time windowing, interleaving, and others are well known in the art and are not shown for brevity.
FIGURE 6 illustrates a receiver block diagram 600 for a PDSCH in a subframe according to embodiments of the present disclosure. The embodiment of the diagram 600 illustrated in FIGURE 6 is for illustration only. One or more of the components illustrated in FIGURE 6 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions. FIGURE 6 does not limit the scope of this disclosure to any particular implementation of the diagram 600.
As shown in FIGURE 6, a received signal 610 is filtered by filter 620, REs 630 for an assigned reception BW are selected by BW selector 635, unit 640 applies a fast Fourier transform (FFT), and an output is serialized by a parallel-to-serial converter 650. Subsequently, a demodulator 660 coherently demodulates data symbols by applying a channel estimate obtained from a DMRS or a CRS (not shown), and a decoder 670, such as a turbo decoder, decodes the demodulated data to provide an estimate of the information data bits 680. Additional functionalities such as time-windowing, cyclic prefix removal, de-scrambling, channel estimation, and de-interleaving are not shown for brevity.
FIGURE 7 illustrates a transmitter block diagram 700 for a PUSCH in a subframe according to embodiments of the present disclosure. The embodiment of the block diagram 700 illustrated in FIGURE 7 is for illustration only. One or more of the components illustrated in FIGURE 5 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions. FIGURE 7 does not limit the scope of this disclosure to any particular implementation of the block diagram 700.
As shown in FIGURE 7, information data bits 710 are encoded by encoder 720, such as a turbo encoder, and modulated by modulator 730. A discrete Fourier transform (DFT) unit 740 applies a DFT on the modulated data bits, REs 750 corresponding to an assigned PUSCH transmission BW are selected by transmission BW selection unit 755, unit 760 applies an IFFT and, after a cyclic prefix insertion (not shown), filtering is applied by filter 770 and a signal transmitted 780.
FIGURE 8 illustrates a receiver block diagram 800 for a PUSCH in a subframe according to embodiments of the present disclosure. The embodiment of the block diagram 800 illustrated in FIGURE 8 is for illustration only. One or more of the components illustrated in FIGURE 8 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions. FIGURE 8 does not limit the scope of this disclosure to any particular implementation of the block diagram 800.
As shown in FIGURE 8, a received signal 810 is filtered by filter 820. Subsequently, after a cyclic prefix is removed (not shown), unit 830 applies a FFT, REs 840 corresponding to an assigned PUSCH reception BW are selected by a reception BW selector 845, unit 850 applies an inverse DFT (IDFT), a demodulator 860 coherently demodulates data symbols by applying a channel estimate obtained from a DMRS (not shown), a decoder 870, such as a turbo decoder, decodes the demodulated data to provide an estimate of the information data bits 880.
In next generation cellular systems, various use cases are envisioned beyond the capabilities of LTE system. Termed 5G or the fifth generation cellular system, a system capable of operating at sub-6GHz and above-6 GHz (for example, in mmWave regime) becomes one of the requirements. In 3GPP TR 22.891, 74 5G use cases have been identified and described; those use cases can be roughly categorized into three different groups. A first group is termed "enhanced mobile broadband (eMBB)," targeted to high data rate services with less stringent latency and reliability requirements. A second group is termed "ultra-reliable and low latency (URLL)" targeted for applications with less stringent data rate requirements, but less tolerant to latency. A third group is termed "massive MTC (mMTC)" targeted for large number of low-power device connections such as 1 million per km2 with less stringent the reliability, data rate, and latency requirements.
FIGURE 9 illustrates an example antenna blocks or arrays 900 according to embodiments of the present disclosure. The embodiment of the antenna blocks or arrays 900 illustrated in FIGURE 9 is for illustration only. FIGURE 9 does not limit the scope of this disclosure to any particular implementation of the antenna blocks or arrays 900.
For mmWave bands, although the number of antenna elements can be larger for a given form factor, the number of CSI-RS ports -which can correspond to the number of digitally precoded ports - tends to be limited due to hardware constraints (such as the feasibility to install a large number of ADCs/DACs at mmWave frequencies) as illustrated in FIGURE 9. In this case, one CSI-RS port is mapped onto a large number of antenna elements which can be controlled by a bank of analog phase shifters 901. One CSI-RS port can then correspond to one sub-array which produces a narrow analog beam through analog beamforming 905. This analog beam can be configured to sweep across a wider range of angles (920) by varying the phase shifter bank across symbols or subframes. The number of sub-arrays (equal to the number of RF chains) is the same as the number of CSI-RS ports NCSI-PORT. A digital beamforming unit 910 performs a linear combination across NCSI-PORT analog beams to further increase precoding gain. While analog beams are wideband (hence not frequency-selective), digital precoding can be varied across frequency sub-bands or resource blocks.
To enable digital precoding, efficient design of CSI-RS is a crucial factor. For this reason, three types of CSI reporting mechanisms corresponding to three types of CSI-RS measurement behavior are supported, for example, "CLASS A" CSI reporting which corresponds to non-precoded CSI-RS, "CLASS B" reporting with K=1 CSI-RS resource which corresponds to UE-specific beamformed CSI-RS, and "CLASS B" reporting with K>1 CSI-RS resources which corresponds to cell-specific beamformed CSI-RS.
For non-precoded (NP) CSI-RS, a cell-specific one-to-one mapping between CSI-RS port and TXRU is utilized. Different CSI-RS ports have the same wide beam width and direction and hence generally cell wide coverage. For beamformed CSI-RS, beamforming operation, either cell-specific or UE-specific, is applied on a non-zero-power (NZP) CSI-RS resource (e.g., comprising multiple ports). At least at a given time/frequency, CSI-RS ports have narrow beam widths and hence not cell wide coverage, and at least from the gNB perspective. At least some CSI-RS port-resource combinations have different beam directions.
In scenarios where DL long-term channel statistics can be measured through UL signals at a serving eNodeB, UE-specific BF CSI-RS can be readily used. This is typically feasible when UL-DL duplex distance is sufficiently small. When this condition does not hold, however, some UE feedback is necessary for the eNodeB to obtain an estimate of DL long-term channel statistics (or any of representation thereof). To facilitate such a procedure, a first BF CSI-RS transmitted with periodicity T1 (ms) and a second NP CSI-RS transmitted with periodicity T2 (ms), where T1 ≤ T2. This approach is termed hybrid CSI-RS. The implementation of hybrid CSI-RS is largely dependent on the definition of CSI process and NZP CSI-RS resource.
In a wireless communication system, MIMO is often identified as an essential feature in order to achieve high system throughput requirements. One of the key components of a MIMO transmission scheme is the accurate CSI acquisition at the eNB (or gNB) (or TRP). For MU-MIMO, in particular, the availability of accurate CSI is necessary in order to guarantee high MU performance. For TDD systems, the CSI can be acquired using the SRS transmission relying on the channel reciprocity. For FDD systems, on the other hand, it can be acquired using the CSI-RS transmission from eNB (or gNB), and CSI acquisition and feedback from UE. In legacy FDD systems, the CSI feedback framework is 'implicit' in the form of CQI/PMI/RI (also CRI and LI) derived from a codebook assuming SU transmission from eNB (or gNB). Because of the inherent SU assumption while deriving CSI, this implicit CSI feedback is inadequate for MU transmission. Since future (e.g., NR) systems are likely to be more MU-centric, this SU-MU CSI mismatch will be a bottleneck in achieving high MU performance gains. Another issue with implicit feedback is the scalability with larger number of antenna ports at eNB (or gNB). For large number of antenna ports, the codebook design for implicit feedback is quite complicated (for example, a total number of 44 Class A codebooks in the 3GPP LTE specification), and the designed codebook is not guaranteed to bring justifiable performance benefits in practical deployment scenarios (for example, only a small percentage gain can be shown at the most). Realizing aforementioned issues, the 3GPP specification also supports advanced CSI reporting in LTE.
In 5G or NR systems [REF7, REF8], the above-mentioned "implicit" CSI reporting paradigm from LTE is also supported and referred to as Type I CSI reporting. In addition, a high-resolution CSI reporting, referred to as Type II CSI reporting, is also supported to provide more accurate CSI information to gNB for use cases such as high-order MU-MIMO. However, the overhead of Type II CSI reporting can be an issue in practical UE implementations. One approach to reduce Type II CSI overhead is based on frequency domain (FD) compression. In Rel. 16 NR, DFT-based FD compression of the Type II CSI has been supported (referred to as Rel. 16 enhanced Type II codebook in REF8). Some of the key components for this feature includes (a) spatial domain (SD) basis
Figure PCTKR2021018843-appb-I000053
, (b) FD basis
Figure PCTKR2021018843-appb-I000054
, and (c) coefficients  
Figure PCTKR2021018843-appb-I000055
that linearly combine SD and FD basis. In a non-reciprocal FDD system, a complete CSI (comprising all components) needs to be reported by the UE. However, when reciprocity or partial reciprocity does exist between UL and DL, then some of the CSI components can be obtained based on the UL channel estimated using SRS transmission from the UE. In Rel. 16 NR, the DFT-based FD compression is extended to this partial reciprocity case (referred to as Rel. 16 enhanced Type II port selection codebook in REF8), wherein the DFT-based SD basis in
Figure PCTKR2021018843-appb-I000056
is replaced with SD CSI-RS port selection, i.e.,
Figure PCTKR2021018843-appb-I000057
out of
Figure PCTKR2021018843-appb-I000058
CSI-RS ports are selected (the selection is common for the two antenna polarizations or two halves of the CSI-RS ports). The CSI-RS ports in this case are beamformed in SD (assuming UL-DL channel reciprocity in angular domain), and the beamforming information can be obtained at the gNB based on UL channel estimated using SRS measurements.
FIGURE 10 illustrates an example distributed MIMO (D-MIMO) system 1000 according to embodiments of the present disclosure. The embodiment of the distributed MIMO (D-MIMO) system 1000 illustrated in FIGURE 10 is for illustration only. FIGURE 10 does not limit the scope of this disclosure to any particular implementation of the distributed MIMO (D-MIMO) system 1000.
NR supports up to 32 CSI-RS antenna ports. For a cellular system operating in a sub-1GHz frequency range (e.g., less than 1 GHz), supporting a large number of CSI-RS antenna ports (e.g., 32) at one site or remote radio head (RRH) is challenging due to larger antenna form factors at these frequencies (when compared with a system operating at a higher frequency such as 2 GHz or 4 GHz). At such low frequencies, the maximum number of CSI-RS antenna ports that can be co-located at a site (or RRH) can be limited, for example to 8. This limits the spectral efficiency of such systems. In particular, the MU-MIMO spatial multiplexing gains offered due to large number of CSI-RS antenna ports (such as 32) can't be achieved. One way to operate a sub-1GHz system with large number of CSI-RS antenna ports is based on distributing antenna ports at multiple sites (or RRHs). The multiple sites or RRHs can still be connected to a single (common) baseband unit, hence the signal transmitted/received via multiple distributed RRHs can still be processed at a centralized location. For example, 32 CSI-RS ports can be distributed across 4 RRHs, each with 8 antenna ports. Such a MIMO system can be referred to as a distributed MIMO (D-MIMO) system as illustrated in FIGURE 10.
All the following components and embodiments are applicable for UL transmission with CP-OFDM (cyclic prefix OFDM) waveform as well as DFT-SOFDM (DFT-spread OFDM) and SC-FDMA (single-carrier FDMA) waveforms. Furthermore, all the following components and embodiments are applicable for UL transmission when the scheduling unit in time is either one subframe (which can consist of one or multiple slots) or one slot.
In the present disclosure, the frequency resolution (reporting granularity) and span (reporting bandwidth) of CSI reporting can be defined in terms of frequency "subbands" and "CSI reporting band" (CRB), respectively.
A subband for CSI reporting is defined as a set of contiguous PRBs which represents the smallest frequency unit for CSI reporting. The number of PRBs in a subband can be fixed for a given value of DL system bandwidth, configured either semi-statically via higher-layer/RRC signaling, or dynamically via L1 DL control signaling or MAC control element (MAC CE). The number of PRBs in a subband can be included in CSI reporting setting.
"CSI reporting band" is defined as a set/collection of subbands, either contiguous or non-contiguous, wherein CSI reporting is performed. For example, CSI reporting band can include all the subbands within the DL system bandwidth. This can also be termed "full-band". Alternatively, CSI reporting band can include only a collection of subbands within the DL system bandwidth. This can also be termed "partial band".
The term "CSI reporting band" is used only as an example for representing a function. Other terms such as "CSI reporting subband set" or "CSI reporting bandwidth" can also be used.
In terms of UE configuration, a UE can be configured with at least one CSI reporting band. This configuration can be semi-static (via higher-layer signaling or RRC) or dynamic (via MAC CE or L1 DL control signaling). When configured with multiple (N) CSI reporting bands (e.g., via RRC signaling), a UE can report CSI associated with nN CSI reporting bands. For instance, > 6GHz, large system bandwidth may require multiple CSI reporting bands. The value of n can either be configured semi-statically (via higher-layer signaling or RRC) or dynamically (via MAC CE or L1 DL control signaling). Alternatively, the UE can report a recommended value of n via an UL channel.
Therefore, CSI parameter frequency granularity can be defined per CSI reporting band as follows. A CSI parameter is configured with "single" reporting for the CSI reporting band with Mn subbands when one CSI parameter for all the Mn subbands within the CSI reporting band. A CSI parameter is configured with "subband" for the CSI reporting band with Mn subbands when one CSI parameter is reported for each of the Mn subbands within the CSI reporting band.
FIGURE 11 illustrates an example antenna port layout 1100 according to embodiments of the present disclosure. The embodiment of the antenna port layout 1100 illustrated in FIGURE 11 is for illustration only. FIGURE 11 does not limit the scope of this disclosure to any particular implementation of the antenna port layout 1100.
As illustrated in FIGURE 11, N1 and N2 are the number of antenna ports with the same polarization in the first and second dimensions, respectively. For 2D antenna port layouts, N1 > 1, N2 > 1, and for 1D antenna port layouts N1 > 1 and N2 = 1. Therefore, for a dual-polarized antenna port layout, the total number of antenna ports is 2N1N2 when each antenna maps to an antenna port. An illustration is shown in FIGURE 11 where "X" represents two antenna polarizations. In this disclosure, the term "polarization" refers to a group of antenna ports. For example, antenna ports
Figure PCTKR2021018843-appb-I000059
comprise a first antenna polarization, and antenna ports
Figure PCTKR2021018843-appb-I000060
comprise a second antenna polarization, where
Figure PCTKR2021018843-appb-I000061
is a number of CSI-Rs antenna ports and
Figure PCTKR2021018843-appb-I000062
is a starting antenna port number (e.g.,
Figure PCTKR2021018843-appb-I000063
, then antenna ports are 3000, 3001, 3002, ...).
Let
Figure PCTKR2021018843-appb-I000064
be a number of antenna panels at the gNB. When there are multiple antenna panels (
Figure PCTKR2021018843-appb-I000065
), we assume that each panel is dual-polarized antenna ports with
Figure PCTKR2021018843-appb-I000066
and
Figure PCTKR2021018843-appb-I000067
ports in two dimensions. This is illustrated in FIGURE 11. Note that the antenna port layouts may or may not be the same in different antenna panels.
As described in Section 5.2.2.2.1 of [REF 8], the Type I single-panel codebook has the following rank 1 (1-layer) pre-coder structure:
Figure PCTKR2021018843-appb-I000068
where
Figure PCTKR2021018843-appb-I000069
is a number of CSI-RS antenna ports,
Figure PCTKR2021018843-appb-I000070
is a co-phase value across two antenna polarizations, and
Figure PCTKR2021018843-appb-I000071
is a two-dimensional DFT vector. The supported values of
Figure PCTKR2021018843-appb-I000072
is
Figure PCTKR2021018843-appb-I000073
, which corresponds to QPSK co-phase
Figure PCTKR2021018843-appb-I000074
. The supported values of
Figure PCTKR2021018843-appb-I000075
is given by Table 1.
Table 1: Supported configurations of
Figure PCTKR2021018843-appb-I000076
and
Figure PCTKR2021018843-appb-I000077
Figure PCTKR2021018843-appb-I000078
As described in Section 5.2.2.2.2 of [REF 8], the Type I multi-panel codebook has the following rank 1 (1-layer) pre-coder structure for codebookMode = 1:
Figure PCTKR2021018843-appb-I000079
where
Figure PCTKR2021018843-appb-I000080
with
Figure PCTKR2021018843-appb-I000081
and the following rank 1 (1-layer) pre-coder structure for codebookMode = 2:
Figure PCTKR2021018843-appb-I000082
where
Figure PCTKR2021018843-appb-I000083
with
Figure PCTKR2021018843-appb-I000084
where
Figure PCTKR2021018843-appb-I000085
is a number of CSI-RS antenna ports. For codebookMode = 1, the supported values for each of
Figure PCTKR2021018843-appb-I000086
,
Figure PCTKR2021018843-appb-I000087
,
Figure PCTKR2021018843-appb-I000088
,
Figure PCTKR2021018843-appb-I000089
is
Figure PCTKR2021018843-appb-I000090
, which corresponds to QPSK co-phase
Figure PCTKR2021018843-appb-I000091
. For codebookMode = 2, the supported values of
Figure PCTKR2021018843-appb-I000092
is
Figure PCTKR2021018843-appb-I000093
, which indicates QPSK co-phase
Figure PCTKR2021018843-appb-I000094
, the supported values for each of
Figure PCTKR2021018843-appb-I000095
,
Figure PCTKR2021018843-appb-I000096
is
Figure PCTKR2021018843-appb-I000097
, which indicates co-phase
Figure PCTKR2021018843-appb-I000098
, and the supported values for each of
Figure PCTKR2021018843-appb-I000099
,
Figure PCTKR2021018843-appb-I000100
is
Figure PCTKR2021018843-appb-I000101
, which indicates co-phase
Figure PCTKR2021018843-appb-I000102
. That is,
Figure PCTKR2021018843-appb-I000103
The supported values of
Figure PCTKR2021018843-appb-I000104
is given by Table 2.
Table 2: Supported configurations of
Figure PCTKR2021018843-appb-I000105
and
Figure PCTKR2021018843-appb-I000106
Figure PCTKR2021018843-appb-I000107
An illustration of Rel. 15 Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission is shown in FIGURE 12. It will be understood by those skilled in the art that FIGURE 12 illustrates an example Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission 1200 according to embodiments of the present disclosure. The embodiment of the Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission 1200 illustrated in FIGURE 12 is for illustration only. FIGURE 12 does not limit the scope of this disclosure to any particular implementation of the Type I single panel (SP) and Type I multi-panel (MP) codebook based MIMO transmission 1200.
In this disclosure, several codebook design alternatives for D-MIMO antenna structure are proposed.
In one example, the antenna architecture of a D-MIMO system is structured. For example, the antenna structure at each RRH is dual-polarized (single or multi-panel as shown in FIGURE 11. The antenna structure at each RRH can be the same. Alternatively, the antenna structure at an RRH can be different from another RRH. Likewise, the number of ports at each RRH can be the same. Alternatively, the number of ports of one RRH can be different from another RRH.
In another example, the antenna architecture of a D-MIMO system is unstructured. For example, the antenna structure at one RRH can be different from another RRH.
We assume a structured antenna architecture in this disclosure.
In one embodiment I.1, a UE is configured with a D-MIMO codebook (e.g., via higher layer signaling), wherein a value for the number of RRHs is parameterized by
Figure PCTKR2021018843-appb-I000108
.
In one example I.1.1, a value of
Figure PCTKR2021018843-appb-I000109
is fixed. For example,
Figure PCTKR2021018843-appb-I000110
= 2 or 3 or 4 or 8.
In one example I.1.2, a value of
Figure PCTKR2021018843-appb-I000111
is configured, e.g., as part of the codebook configuration or CSI reporting configuration via RRC signaling, or indicated via MAC CE or DCI or a combination of two or more of RRC, MAC CE and DCI. The value of
Figure PCTKR2021018843-appb-I000112
is configured from a set of supported values. In one example, the set of supported values is
Figure PCTKR2021018843-appb-I000113
or
Figure PCTKR2021018843-appb-I000114
or
Figure PCTKR2021018843-appb-I000115
or
Figure PCTKR2021018843-appb-I000116
.
In one example, a separate RRC parameter is used to configure a value for
Figure PCTKR2021018843-appb-I000117
.
In one example, a joint RRC parameter is used to configure a value for
Figure PCTKR2021018843-appb-I000118
and a value for at least one additional parameter. For example, the parameter
Figure PCTKR2021018843-appb-I000119
in Rel. 15 Type I multi-panel codebook can be used as a joint parameter for both
Figure PCTKR2021018843-appb-I000120
and
Figure PCTKR2021018843-appb-I000121
.
In one example I.1.3, a value of
Figure PCTKR2021018843-appb-I000122
(whether fixed or configured) is subject to a constraint (or condition). In one example of the constraint, the total number of ports across all RRHs belongs to a set of values
Figure PCTKR2021018843-appb-I000123
or
Figure PCTKR2021018843-appb-I000124
or
Figure PCTKR2021018843-appb-I000125
or
Figure PCTKR2021018843-appb-I000126
.
In one embodiment I.2, the total number of ports across all RRHs, denoted as
Figure PCTKR2021018843-appb-I000127
, is determined according to at least one of the following examples.
In one example I.2.1,
Figure PCTKR2021018843-appb-I000128
wherein it is assumed that the antenna structure is the same at each RRH, i.e.,
Figure PCTKR2021018843-appb-I000129
for all
Figure PCTKR2021018843-appb-I000130
. In one example,
Figure PCTKR2021018843-appb-I000131
where
Figure PCTKR2021018843-appb-I000132
is a parameter for
Figure PCTKR2021018843-appb-I000133
-th RRH, assuming that the antenna structure can be different across RRHs, i.e.,
Figure PCTKR2021018843-appb-I000134
.
The parameter
Figure PCTKR2021018843-appb-I000135
can be configured via RRC, e.g., based on Table 1 for Rel. 15 Type I single panel (or multi-panel) codebook. Likewise, the parameters
Figure PCTKR2021018843-appb-I000136
for each
Figure PCTKR2021018843-appb-I000137
can be configured via RRC, e.g., based on Table 1 for Rel. 15 Type I single panel (or multi-panel) codebook. In one example,
Figure PCTKR2021018843-appb-I000138
is configured (via RRC) similar to Rel. 15 Type I multi-panel codebook, Table 2, by mapping them to
Figure PCTKR2021018843-appb-I000139
. In one example, when
Figure PCTKR2021018843-appb-I000140
, the value
Figure PCTKR2021018843-appb-I000141
or
Figure PCTKR2021018843-appb-I000142
.
In one example I.2.1A,
Figure PCTKR2021018843-appb-I000143
wherein it is assumed that the antenna structure is the same at each RRH, i.e.,
Figure PCTKR2021018843-appb-I000144
for all
Figure PCTKR2021018843-appb-I000145
. In one example,
Figure PCTKR2021018843-appb-I000146
where
Figure PCTKR2021018843-appb-I000147
is a parameter for
Figure PCTKR2021018843-appb-I000148
-th RRH, assuming that the antenna structure can be different across RRHs. The parameter
Figure PCTKR2021018843-appb-I000149
can be configured via RRC, e.g., from {2,4,8,12,16,24,32} or {4,8,12,16,24,32}. Likewise, the parameter
Figure PCTKR2021018843-appb-I000150
for each
Figure PCTKR2021018843-appb-I000151
can be configured via RRC, e.g., from {2,4,8,12,16,24,32} or {4,8,12,16,24,32}.
In one example,
Figure PCTKR2021018843-appb-I000152
and
Figure PCTKR2021018843-appb-I000153
values are such that
Figure PCTKR2021018843-appb-I000154
belongs to {4,8,12,16,24,32} or {4,8,12,16,24,32,48} or {4,8,12,16,24,32,48,64} or {8,12,16,24,32} or {8,12,16,24,32,48} or {8,12,16,24,32,48,64}.
Figure PCTKR2021018843-appb-I000155
In one example, when
Figure PCTKR2021018843-appb-I000156
,
Figure PCTKR2021018843-appb-I000157
belongs to {2,4,8,12,16} or {2,4,8,12,16,24} or {2,4,8,12,16,24,32} or {4,8,12,16} or {4,8,12,16,24} or {4,8,12,16,24,32}.
Figure PCTKR2021018843-appb-I000158
In one example, when
Figure PCTKR2021018843-appb-I000159
,
Figure PCTKR2021018843-appb-I000160
belongs to {2,4,8} or {2,4,8,12} or {2,4,8,12,16} or {4,8} or {4,8,12} or {4,8,12,16}.
Figure PCTKR2021018843-appb-I000161
In one example, when
Figure PCTKR2021018843-appb-I000162
,
Figure PCTKR2021018843-appb-I000163
belongs to {2,4} or {2,4,8} or {4} or {4,8}.
In one example,
Figure PCTKR2021018843-appb-I000164
values for
Figure PCTKR2021018843-appb-I000165
and different values of the total number of CSI-RS ports is according to at least one of the examples in Table 3.
Table 3
Figure PCTKR2021018843-appb-I000166
In one example, the UE is configured with one CSI-RS resource with
Figure PCTKR2021018843-appb-I000167
CSI-RS ports that are distributed across all RRHs. In one example, the UE is configured with
Figure PCTKR2021018843-appb-I000168
CSI-RS resources, where the
Figure PCTKR2021018843-appb-I000169
-th CSI-RS resource with
Figure PCTKR2021018843-appb-I000170
CSI-RS ports is associated with the
Figure PCTKR2021018843-appb-I000171
-th RRH.
In one example I.2.2,
Figure PCTKR2021018843-appb-I000172
wherein it is assumed that the antenna structure is the same at each RRH, i.e.,
Figure PCTKR2021018843-appb-I000173
for all
Figure PCTKR2021018843-appb-I000174
. In one example,
Figure PCTKR2021018843-appb-I000175
where
Figure PCTKR2021018843-appb-I000176
is a parameter for
Figure PCTKR2021018843-appb-I000177
-th RRH, assuming that the antenna structure can be different across RRHs, i.e.,
Figure PCTKR2021018843-appb-I000178
.
In one example I.2.3,
Figure PCTKR2021018843-appb-I000179
wherein
Figure PCTKR2021018843-appb-I000180
(e.g., co-polarized antenna) or 2 (e.g., dual-polarized antenna) and it is assumed that the antenna structure is the same at each RRH, i.e.,
Figure PCTKR2021018843-appb-I000181
for all
Figure PCTKR2021018843-appb-I000182
. In one example,
Figure PCTKR2021018843-appb-I000183
where
Figure PCTKR2021018843-appb-I000184
=1 or 2 and
Figure PCTKR2021018843-appb-I000185
is a parameter for
Figure PCTKR2021018843-appb-I000186
-th RRH, assuming that the antenna structure can be different across RRHs, i.e.,
Figure PCTKR2021018843-appb-I000187
. The value of
Figure PCTKR2021018843-appb-I000188
can be the same across RRHs. Alternatively, it can be different, hence can vary across RRHs.
In one embodiment I.3, the CSI-RS port numbering for D-MIMO is according to at least one of the following examples.
In one example I.3.1, the CSI-RS ports are numbered in the following order: CSI-RS ports for RRH1, CSI-RS ports for RRH2 and so on.
Figure PCTKR2021018843-appb-I000189
In one example I.3.2, the CSI-RS ports are numbered in the following order: CSI-RS ports with a first polarization for RRH1, CSI-RS ports with a second polarization for RRH1, CSI-RS ports with a first polarization for RRH2, CSI-RS ports with a second polarization for RRH2, and so on.
Figure PCTKR2021018843-appb-I000190
In one example I.3.3, the CSI-RS ports are numbered in the following order: CSI-RS ports with a first polarization for RRH1, CSI-RS ports with a first polarization for RRH2, ..., CSI-RS ports with a second polarization for RRH1, CSI-RS ports with a second polarization for RRH2.
In one example, a first polarization refers to one first half (a first group) of the antenna ports with a first antenna polarization (e.g., +45), and a second polarization refers to one second half (a second group) of the antenna ports with a second antenna polarization (e.g., -45).
In one embodiment II.1, a UE is configured with a D-MIMO codebook (e.g., via higher layer signaling) which has a dual-stage pre-coder structure (for each layer), e.g., similar to (or based on) Rel. 15 NR Type II codebooks, or a triple-stage pre-coder structure (for each layer), e.g., similar to (or based on) Rel. 16 NR Type II codebooks. For the two-stage, the pre-coder for a layer can be represented as
Figure PCTKR2021018843-appb-I000191
where the component
Figure PCTKR2021018843-appb-I000192
is used to report/indicate a basis matrix comprising
Figure PCTKR2021018843-appb-I000193
basis vectors, and the component
Figure PCTKR2021018843-appb-I000194
is used to report/indicate one out of
Figure PCTKR2021018843-appb-I000195
basis vector selection (for each layer), which is common for two polarizations, and a co-phase value for the two polarizations. Note that when
Figure PCTKR2021018843-appb-I000196
, there is no need for any beam selection via
Figure PCTKR2021018843-appb-I000197
. For the three stage, the
Figure PCTKR2021018843-appb-I000198
pre-coders for a layer can be represented as
Figure PCTKR2021018843-appb-I000199
where the component
Figure PCTKR2021018843-appb-I000200
is used to report/indicate a spatial domain (SD) basis matrix comprising SD basis vectors, the component
Figure PCTKR2021018843-appb-I000201
is used to report/indicate a frequency domain (FD) basis matrix comprising FD basis vectors, and the component
Figure PCTKR2021018843-appb-I000202
is used to report/indicate coefficients corresponding to SD and FD basis vector pairs.
FIGURE 13 illustrates an example D-MIMO 1300 where each RRH has a single antenna panel according to embodiments of the present disclosure. The embodiment of the D-MIMO 1300 where each RRH has a single antenna panel illustrated in FIGURE 13 is for illustration only. FIGURE 13 does not limit the scope of this disclosure to any particular implementation of the D-MIMO 1300 where each RRH has a single antenna panel.
As illustrated in FIGURE 13, in one embodiment II.2, each RRH has a single antenna panel. The component
Figure PCTKR2021018843-appb-I000203
has a block diagonal structure comprising
Figure PCTKR2021018843-appb-I000204
diagonal blocks, where 1 (co-pol) or 2 (dual-pol) diagonal blocks are associated with each RRH.
In one example II.2.1,
Figure PCTKR2021018843-appb-I000205
assuming co-polarized (single polarized) antenna structure at each RRH. In one example, when
Figure PCTKR2021018843-appb-I000206
, the components
Figure PCTKR2021018843-appb-I000207
is given by
Figure PCTKR2021018843-appb-I000208
where
Figure PCTKR2021018843-appb-I000209
is a basis matrix for the 1st RRH, and
Figure PCTKR2021018843-appb-I000210
is a basis matrix for the 2nd RRH. In one example,
Figure PCTKR2021018843-appb-I000211
comprises
Figure PCTKR2021018843-appb-I000212
columns or beams (or basis vectors) for
Figure PCTKR2021018843-appb-I000213
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000214
for all
Figure PCTKR2021018843-appb-I000215
values (RRH-common
Figure PCTKR2021018843-appb-I000216
value), for example,
Figure PCTKR2021018843-appb-I000217
. In one example,
Figure PCTKR2021018843-appb-I000218
can be different across RRHs (RRH-specific
Figure PCTKR2021018843-appb-I000219
value), for example,
Figure PCTKR2021018843-appb-I000220
can take a value (fixed or configured) from {1,4}.
In one example II.2.2,
Figure PCTKR2021018843-appb-I000221
assuming dual-polarized (cross-polarized) antenna structure at each RRH.
In one example, when
Figure PCTKR2021018843-appb-I000222
, the components
Figure PCTKR2021018843-appb-I000223
is given by
Figure PCTKR2021018843-appb-I000224
where
Figure PCTKR2021018843-appb-I000225
is a basis matrix for the 1st RRH and is common (the same) for the two polarizations, which correspond to the first and second diagonal blocks, and
Figure PCTKR2021018843-appb-I000226
is a basis matrix for the 2nd RRH and is common (the same) for the two polarizations, which correspond to the third and fourth diagonal blocks. In general,
Figure PCTKR2021018843-appb-I000227
-th and
Figure PCTKR2021018843-appb-I000228
-th diagonal blocks correspond to the two antenna polarizations for the
Figure PCTKR2021018843-appb-I000229
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000230
comprises
Figure PCTKR2021018843-appb-I000231
columns or beams (or basis vectors) for
Figure PCTKR2021018843-appb-I000232
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000233
for all
Figure PCTKR2021018843-appb-I000234
values (RRH-common
Figure PCTKR2021018843-appb-I000235
value), for example,
Figure PCTKR2021018843-appb-I000236
. In one example,
Figure PCTKR2021018843-appb-I000237
can be different across RRHs (RRH-specific
Figure PCTKR2021018843-appb-I000238
value), for example,
Figure PCTKR2021018843-appb-I000239
can take a value (fixed or configured) from {1,4}.
In one example, when
Figure PCTKR2021018843-appb-I000240
, the components
Figure PCTKR2021018843-appb-I000241
is given by
Figure PCTKR2021018843-appb-I000242
where
Figure PCTKR2021018843-appb-I000243
is a basis matrix for the 1st RRH and is common (the same) for the two polarizations, which correspond to the first and third diagonal blocks, and
Figure PCTKR2021018843-appb-I000244
is a basis matrix for the 2nd RRH and is common (the same) for the two polarizations, which correspond to the second and fourth diagonal blocks. In general,
Figure PCTKR2021018843-appb-I000245
-th and
Figure PCTKR2021018843-appb-I000246
-th diagonal blocks correspond to the two antenna polarizations for the
Figure PCTKR2021018843-appb-I000247
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000248
comprises
Figure PCTKR2021018843-appb-I000249
columns or beams (or basis vectors) for
Figure PCTKR2021018843-appb-I000250
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000251
for all
Figure PCTKR2021018843-appb-I000252
values (RRH-common
Figure PCTKR2021018843-appb-I000253
value), for example,
Figure PCTKR2021018843-appb-I000254
. In one example,
Figure PCTKR2021018843-appb-I000255
can be different across RRHs (RRH-specific
Figure PCTKR2021018843-appb-I000256
value), for example,
Figure PCTKR2021018843-appb-I000257
can take a value (fixed or configured) from {1,4}.
In one example, when
Figure PCTKR2021018843-appb-I000258
, the components
Figure PCTKR2021018843-appb-I000259
is given by
Figure PCTKR2021018843-appb-I000260
where
Figure PCTKR2021018843-appb-I000261
and
Figure PCTKR2021018843-appb-I000262
are basis matrices for the first and second antenna polarizations of the 1st RRH, which correspond to the first and second diagonal blocks, and
Figure PCTKR2021018843-appb-I000263
and
Figure PCTKR2021018843-appb-I000264
are basis matrices for the first and second antenna polarizations of the 2nd RRH, which correspond to the third and fourth diagonal blocks. In general,
Figure PCTKR2021018843-appb-I000265
-th and
Figure PCTKR2021018843-appb-I000266
-th diagonal blocks correspond to the two antenna polarizations for the
Figure PCTKR2021018843-appb-I000267
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000268
comprises
Figure PCTKR2021018843-appb-I000269
columns or beams (or basis vectors) for
Figure PCTKR2021018843-appb-I000270
-th polarization of
Figure PCTKR2021018843-appb-I000271
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000272
for all
Figure PCTKR2021018843-appb-I000273
and
Figure PCTKR2021018843-appb-I000274
values (RRH-common and polarization-common
Figure PCTKR2021018843-appb-I000275
value), for example
Figure PCTKR2021018843-appb-I000276
. In one example,
Figure PCTKR2021018843-appb-I000277
for all
Figure PCTKR2021018843-appb-I000278
values (RRH-specific and polarization-common
Figure PCTKR2021018843-appb-I000279
value). In one example,
Figure PCTKR2021018843-appb-I000280
for all
Figure PCTKR2021018843-appb-I000281
values (RRH-common and polarization-specific
Figure PCTKR2021018843-appb-I000282
value). In one example,
Figure PCTKR2021018843-appb-I000283
can be different across RRHs (RRH-specific and polarization-specific
Figure PCTKR2021018843-appb-I000284
value).
In one example, when
Figure PCTKR2021018843-appb-I000285
, the components
Figure PCTKR2021018843-appb-I000286
is given by
Figure PCTKR2021018843-appb-I000287
where
Figure PCTKR2021018843-appb-I000288
and
Figure PCTKR2021018843-appb-I000289
are basis matrices for the first and second antenna polarizations of the 1st RRH, which correspond to the first and third diagonal blocks, and
Figure PCTKR2021018843-appb-I000290
and
Figure PCTKR2021018843-appb-I000291
are basis matrices for the first and second antenna polarizations of the 2nd RRH, which correspond to the second and fourth diagonal blocks. In general,
Figure PCTKR2021018843-appb-I000292
-th and
Figure PCTKR2021018843-appb-I000293
-th diagonal blocks correspond to the two antenna polarizations for the
Figure PCTKR2021018843-appb-I000294
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000295
comprises
Figure PCTKR2021018843-appb-I000296
columns or beams (or basis vectors) for
Figure PCTKR2021018843-appb-I000297
-th polarization of
Figure PCTKR2021018843-appb-I000298
-th RRH. In one example,
Figure PCTKR2021018843-appb-I000299
for all
Figure PCTKR2021018843-appb-I000300
and
Figure PCTKR2021018843-appb-I000301
values (RRH-common and polarization-common
Figure PCTKR2021018843-appb-I000302
value) , for example
Figure PCTKR2021018843-appb-I000303
. In one example,
Figure PCTKR2021018843-appb-I000304
for all
Figure PCTKR2021018843-appb-I000305
values (RRH-specific and polarization-common
Figure PCTKR2021018843-appb-I000306
value). In one example,
Figure PCTKR2021018843-appb-I000307
for all
Figure PCTKR2021018843-appb-I000308
values (RRH-common and polarization-specific
Figure PCTKR2021018843-appb-I000309
value). In one example,
Figure PCTKR2021018843-appb-I000310
can be different across RRHs (RRH-specific and polarization-specific
Figure PCTKR2021018843-appb-I000311
value).
In one example II.2.3,
Figure PCTKR2021018843-appb-I000312
, where
Figure PCTKR2021018843-appb-I000313
for co-polarized (single polarized) antenna structure at
Figure PCTKR2021018843-appb-I000314
-th RRH, and
Figure PCTKR2021018843-appb-I000315
for dual-polarized (cross-polarized) antenna structure at
Figure PCTKR2021018843-appb-I000316
-th RRH.
In one example, when
Figure PCTKR2021018843-appb-I000317
, the components
Figure PCTKR2021018843-appb-I000318
is given by
Figure PCTKR2021018843-appb-I000319
where
Figure PCTKR2021018843-appb-I000320
is a basis matrix for the 1st RRH, and
Figure PCTKR2021018843-appb-I000321
is a basis matrix for the 2nd RRH and is common (the same) for the two polarizations, which correspond to the second and third diagonal blocks.
In one example, when
Figure PCTKR2021018843-appb-I000322
, the components
Figure PCTKR2021018843-appb-I000323
is given by
Figure PCTKR2021018843-appb-I000324
where
Figure PCTKR2021018843-appb-I000325
is a basis matrix for the 1st RRH, and
Figure PCTKR2021018843-appb-I000326
and
Figure PCTKR2021018843-appb-I000327
are basis matrices for the first and second antenna polarizations of the 2nd RRH, which correspond to the second and third diagonal blocks.
FIGURE 14 illustrates an example D-MIMO 1400 where each RRH has multiple antenna panels according to embodiments of the present disclosure. The embodiment of the D-MIMO 1400 where each RRH has multiple antenna panels illustrated in FIGURE 14 is for illustration only. FIGURE 14 does not limit the scope of this disclosure to any particular implementation of the D-MIMO 1400 where each RRH has multiple antenna panels.
As illustrated in FIGURE 14, in one embodiment II.3, each RRH has multiple antenna panels. The component
Figure PCTKR2021018843-appb-I000328
has a block diagonal structure comprising
Figure PCTKR2021018843-appb-I000329
diagonal blocks, where
Figure PCTKR2021018843-appb-I000330
(co-pol) or
Figure PCTKR2021018843-appb-I000331
(dual-pol) diagonal blocks are associated with
Figure PCTKR2021018843-appb-I000332
-th RRH comprising
Figure PCTKR2021018843-appb-I000333
panels and
Figure PCTKR2021018843-appb-I000334
for all values of
Figure PCTKR2021018843-appb-I000335
. Note
Figure PCTKR2021018843-appb-I000336
for both RRHs in FIGURE 14.
The examples in embodiment II.2 can be extended in a straightforward manner in this case (of multiple panels at RRHs) by adding the diagonal blocks corresponding to multiple panels in
Figure PCTKR2021018843-appb-I000337
.
FIGURE 15 illustrates an example D-MIMO 1500 where each RRH can have a single antenna panel or multiple antenna panels according to embodiments of the present disclosure. The embodiment of the D-MIMO 1500 where each RRH can have a single antenna panel or multiple antenna panels illustrated in FIGURE 15 is for illustration only. FIGURE 15 does not limit the scope of this disclosure to any particular implementation of the D-MIMO 1500 where each RRH can have a single antenna panel or multiple antenna panels.
As illustrated in FIGURE 15, in one embodiment II.4, each RRH can have a single antenna panel or multiple antenna panels. The component
Figure PCTKR2021018843-appb-I000338
has a block diagonal structure comprising
Figure PCTKR2021018843-appb-I000339
diagonal blocks, where
Figure PCTKR2021018843-appb-I000340
(co-pol) or
Figure PCTKR2021018843-appb-I000341
(dual-pol) diagonal blocks are associated with
Figure PCTKR2021018843-appb-I000342
-th RRH comprising
Figure PCTKR2021018843-appb-I000343
panels, and
Figure PCTKR2021018843-appb-I000344
when
Figure PCTKR2021018843-appb-I000345
-th RRH has a single panel and
Figure PCTKR2021018843-appb-I000346
when
Figure PCTKR2021018843-appb-I000347
-th RRH has multiple panels.
The examples in embodiment II.2 can be extended in a straightforward manner in this case (of multiple panels at RRHs) by adding the diagonal blocks corresponding to multiple panels in
Figure PCTKR2021018843-appb-I000348
.
In one embodiment II.5, the basis matrices comprising the diagonal blocks of the component
Figure PCTKR2021018843-appb-I000349
have columns that are selected from a set of oversampled 2D DFT vectors. When the antenna port layout is the same across RRHs, for a given antenna port layout
Figure PCTKR2021018843-appb-I000350
and oversampling factors
Figure PCTKR2021018843-appb-I000351
for two dimensions, a DFT vector
Figure PCTKR2021018843-appb-I000352
can be expressed as follows.
Figure PCTKR2021018843-appb-I000353
where
Figure PCTKR2021018843-appb-I000354
and
Figure PCTKR2021018843-appb-I000355
.
When the antenna port layout can be different across RRHs, for a given antenna port layout
Figure PCTKR2021018843-appb-I000356
and oversampling factors
Figure PCTKR2021018843-appb-I000357
associated with
Figure PCTKR2021018843-appb-I000358
-th RRH, a DFT vector
Figure PCTKR2021018843-appb-I000359
can be expressed as follows.
Figure PCTKR2021018843-appb-I000360
where
Figure PCTKR2021018843-appb-I000361
and
Figure PCTKR2021018843-appb-I000362
.
In one example, the oversampling factor is RRH-common, hence remains the same across RRHs. For example, e.g.,
Figure PCTKR2021018843-appb-I000363
. In one example, the oversampling factor is RRH-specific, hence is independent for each RRH. For example,
Figure PCTKR2021018843-appb-I000364
and
Figure PCTKR2021018843-appb-I000365
is chosen (fixed or configured) from {2,4,8}.
In one example, the oversampling factor is fixed, e.g.,
Figure PCTKR2021018843-appb-I000366
for low-resolution (Type I) codebook and
Figure PCTKR2021018843-appb-I000367
for high-resolution (Type II) codebook. In one example, the oversampling factor is configured, e.g., via RRC, where the configured value(s) is common for all RRHs, or independent for each RRH (i.e., one value is configured for each RRH).
In one embodiment II.6, each RRH can have a single antenna panel or multiple antenna panels (cf. FIGURE 15). The component
Figure PCTKR2021018843-appb-I000368
has a block diagonal structure comprising
Figure PCTKR2021018843-appb-I000369
diagonal blocks, where
Figure PCTKR2021018843-appb-I000370
(co-pol) or
Figure PCTKR2021018843-appb-I000371
(dual-pol) diagonal blocks are associated with
Figure PCTKR2021018843-appb-I000372
-th RRH comprising
Figure PCTKR2021018843-appb-I000373
panels, and
Figure PCTKR2021018843-appb-I000374
when
Figure PCTKR2021018843-appb-I000375
-th RRH has a single panel and
Figure PCTKR2021018843-appb-I000376
when
Figure PCTKR2021018843-appb-I000377
-th RRH has multiple panels.
In one embodiment III.1, the codebook includes additional components due to
Figure PCTKR2021018843-appb-I000378
RRHs.
In one example III.1.1, the additional components include inter-RRH phase. In one example, the inter-RRH phase values correspond to
Figure PCTKR2021018843-appb-I000379
phase values (e.g., assuming one of the RRHs is a reference and has a fixed phase value = 1). In another example, the inter-RRH phase values correspond to
Figure PCTKR2021018843-appb-I000380
phase values. The inter-RRH phase values can be quantized/reported as scalars using a scalar codebook (e.g., QPSK, 2 bits per phase or 8PSK, 3 bits per phase) or as a vector using a vector codebook (e.g., a DFT codebook). Also, for a dual-polarized antenna at an RRH, the inter-RRH phase can be the same for two polarizations of the RRH. Alternatively, it can be independent for two polarizations for the RRH. At least one of the following example is used for the inter-RRH phase reporting.
Figure PCTKR2021018843-appb-I000381
In one example III.1.1.1, the inter-RRH phase is reported in a wideband (WB) manner, i.e., one value is reported for all SBs in the configured CSI reporting band. Due to WB reporting, it can be included in the
Figure PCTKR2021018843-appb-I000382
component of the codebook. Alternatively, it can be included in a new component, say
Figure PCTKR2021018843-appb-I000383
of the codebook.
Figure PCTKR2021018843-appb-I000384
In one example III.1.1.2, the inter-RRH phase is reported in a subband (SB) manner, i.e., one value is reported for each SB in the configured CSI reporting band. Due to SB reporting, it can be included in the
Figure PCTKR2021018843-appb-I000385
component of the codebook. Alternatively, it can be included in a new component, say
Figure PCTKR2021018843-appb-I000386
of the codebook.
Figure PCTKR2021018843-appb-I000387
In one example III.1.1.3, the inter-RRH phase is reported in a WB plus SB manner, i.e., one WB phase value is reported for all SBs in the configured CSI reporting band, and one SB value is reported for each SB in the configured CSI reporting band. Due to WB plus SB reporting, the WB part can be included in the
Figure PCTKR2021018843-appb-I000388
component of the codebook and the SB part can be included in the
Figure PCTKR2021018843-appb-I000389
component of the codebook. Alternatively, both WB and SB parts can be included in a new component, say
Figure PCTKR2021018843-appb-I000390
of the codebook.
In one example III.1.2, the additional components include inter-RRH phase and inter-RRH amplitude, wherein the details about the inter-RRH phase are as explained in example III.1.1. Note that inter-RRH amplitude is needed due to unequal distance of the UE from RRHs. In one example, the inter-RRH amplitude values correspond to
Figure PCTKR2021018843-appb-I000391
amplitude values (e.g., assuming one of the RRHs is a reference and has a fixed amplitude value = 1). In another example, the inter-RRH amplitude values correspond to
Figure PCTKR2021018843-appb-I000392
amplitude values. The inter-RRH amplitude values can be quantized/reported as scalars using a scalar codebook (e.g., 2 bits per amplitude or 3 bits per amplitude) or as a vector using a vector codebook. Also, for a dual-polarized antenna at an RRH, the inter-RRH amplitude can be the same for two polarizations of the RRH. Alternatively, it can be independent for two polarizations for the RRH. At least one of the following example is used for the inter-RRH amplitude and phase reporting.
Figure PCTKR2021018843-appb-I000393
In one example III.1.2.1, the inter-RRH amplitude is reported in a wideband (WB) manner, i.e., one value is reported for all SBs in the configured CSI reporting band. Due to WB reporting, it can be included in the
Figure PCTKR2021018843-appb-I000394
component of the codebook. Alternatively, it can be included in a new component, say
Figure PCTKR2021018843-appb-I000395
of the codebook. At least one of the following example is used for the inter-RRH phase.
Figure PCTKR2021018843-appb-I000396
o In one example III.1.2.1.1, the inter-RRH phase is reported is reported according to example III.1.1.1.
Figure PCTKR2021018843-appb-I000397
o In one example III.1.2.1.2, the inter-RRH phase is reported is reported according to example III.1.1.2.
Figure PCTKR2021018843-appb-I000398
o In one example III.1.2.1.3, the inter-RRH phase is reported is reported according to example III.1.1.3.
Figure PCTKR2021018843-appb-I000399
In one example III.1.2.2, the inter-RRH amplitude is reported in a subband (SB) manner, i.e., one value is reported for each SB in the configured CSI reporting band. Due to SB reporting, it can be included in the
Figure PCTKR2021018843-appb-I000400
component of the codebook. Alternatively, it can be included in a new component, say
Figure PCTKR2021018843-appb-I000401
of the codebook. At least one of the following example is used for the inter-RRH phase.
Figure PCTKR2021018843-appb-I000402
o In one example III.1.2.2.1, the inter-RRH phase is reported is reported according to example III.1.1.1.
Figure PCTKR2021018843-appb-I000403
o In one example III.1.2.2.2, the inter-RRH phase is reported is reported according to example III.1.1.2.
Figure PCTKR2021018843-appb-I000404
o In one example III.1.2.2.3, the inter-RRH phase is reported is reported according to example III.1.1.3.
Figure PCTKR2021018843-appb-I000405
In one example III.1.2.3, the inter-RRH amplitude is reported in a WB plus SB manner, i.e., one WB amplitude value is reported for all SBs in the configured CSI reporting band, and one SB value is reported for each SB in the configured CSI reporting band. Due to WB plus SB reporting, the WB part can be included in the
Figure PCTKR2021018843-appb-I000406
component of the codebook and the SB part can be included in the
Figure PCTKR2021018843-appb-I000407
component of the codebook. Alternatively, both WB and SB parts can be included in a new component, say
Figure PCTKR2021018843-appb-I000408
of the codebook. At least one of the following example is used for the inter-RRH phase.
Figure PCTKR2021018843-appb-I000409
o In one example III.1.2.3.1, the inter-RRH phase is reported is reported according to example III.1.1.1.
Figure PCTKR2021018843-appb-I000410
o In one example III.1.2.3.2, the inter-RRH phase is reported is reported according to example III.1.1.2.
Figure PCTKR2021018843-appb-I000411
o In one example III.1.2.3.3, the inter-RRH phase is reported is reported according to example III.1.1.3.
In one example III.1.3, the additional components include inter-RRH amplitude, wherein the details about the inter-RRH amplitude are as explained in example III.1.2.
In one example III.1.4, the additional components include inter-RRH power, wherein the details about the inter-RRH power are as explained in example III.1.2 by replacing amplitude with power. In one example, a square of inter-RRH amplitude equals inter-RRH power.
In one example III.1.5, the additional components include inter-RRH phase and inter-RRH power, wherein the details about the inter-RRH phase are as explained in example III.1.1, and the details about the inter-RRH power are as explained in example III.1.2 by replacing amplitude with power. In one example, a square of inter-RRH amplitude equals inter-RRH power.
In one example III.1.6, the additional components include an indicator indicating the strongest RRH (for reference). Due to distributed architecture, the strongest RRH can be reported in order to indicate the reference RRH with respect to which the inter-RRH components (such as amplitude or/and phase) are reported. The inter-RRH amplitude and phase associated with the strongest RRH can be set to a fixed value, for example 1. At least one of the following example is used for the strongest RRH reporting.
Figure PCTKR2021018843-appb-I000412
In one example III.1.6.1, the strongest RRH (indicator) is reported in a WB manner, i.e., one value (indicator) is reported for all SBs. Due to WB reporting, it can be included in the
Figure PCTKR2021018843-appb-I000413
component of the codebook. Alternatively, it can be included in a new component, say
Figure PCTKR2021018843-appb-I000414
of the codebook.
Figure PCTKR2021018843-appb-I000415
In one example III.1.6.2, the strongest RRH (indicator) is reported in a SB manner, i.e., one value (indicator) is reported for each SB. Due to SB reporting, it can be included in the
Figure PCTKR2021018843-appb-I000416
component of the codebook. Alternatively, it can be included in a new component, say
Figure PCTKR2021018843-appb-I000417
of the codebook.
In one example, the strongest RRH is reported in a layer-common manner, i.e., one strongest RRH is reported common for all layers when number of layers > 1 (or rank > 1).
In one example, the strongest RRH is reported in a layer-specific manner, i.e., one strongest RRH is reported for each layer of the number of layers when number of layers > 1 (or rank > 1).
The amplitude/phase associated with the strongest RRH can be fixed, e.g., to 1. In an alternate design, the strongest RRH can be configured (e.g., via RRC signaling, or indicated via MAC CE or DCI or a combination of two or more of RRC, MAC CE and DCI), or can be fixed (e.g., RRH 1 is always strongest)
In one embodiment III.1.4, an RRH selection is performed wherein a subset of
Figure PCTKR2021018843-appb-I000418
RRHs are selected from the
Figure PCTKR2021018843-appb-I000419
RRHs and the CSI is reported for the selected
Figure PCTKR2021018843-appb-I000420
RRHs. In one example, the RRH selection is configured via RRC signaling, or indicated via MAC CE or DCI or a combination of two or more of RRC, MAC CE and DCI. In another example, the RRH selection is performed by the UE, for example, the UE reports an indicator for this selection or reports inter-RRH amplitude (or power) = 0 indicating that an RRH is not selected.
In one example, the RRH selection is performed in a layer-common manner, i.e., the RRH selection is performed common for all layers when number of layers > 1 (or rank > 1).
In one example, the RRH selection is performed in a layer-specific manner, i.e., the RRH selection is performed for each layer of the number of layers when number of layers > 1 (or rank > 1).
In one example III.1.4.1, the UE is configured with a Type I codebook for D-MIMO (e.g., by setting RRC parameter codebookType = TypeI-D-MIMO), wherein the codebook includes a component for RRH selection (ON/OFF).
In one example, this component is separate (dedicated for RRH selection). For example, a bit sequence comprising
Figure PCTKR2021018843-appb-I000421
bits is used where each bit of the bit sequence is associated with an RRH, and the bit value '1' is used to indicate that the RRH is selected and the bit value '0' is used to indicate that the RRH is not selected. For example, a combinatorial index, indicated via
Figure PCTKR2021018843-appb-I000422
bits signaling, is used to indicate
Figure PCTKR2021018843-appb-I000423
RRH selection hypotheses, W1 basis vector selection in Rel. 15 NR Type I codebook.
In another example, this component is combined (joint) with an amplitude component of the codebook, where the amplitude codebook includes a value 0 (in addition to other values greater than 0), and the value '0' is used to indicate/report that the RRH is not selected and the bit value greater than 0 is used to indicate/report that the RRH is selected and the indicated/reported value indicates the amplitude weighting in the precoder equation/calculation.
In one example III.1.4.2, the UE is configured with a Type II codebook (or Type II port selection) for D-MIMO (e.g., by setting RRC parameter codebookType = TypeII-D-MIMO or TypeII-PortSelection-D-MIMO), wherein the codebook includes a component for RRH selection (ON/OFF).
In one example, this component is separate (dedicated for RRH selection). For example, a bit sequence comprising
Figure PCTKR2021018843-appb-I000424
bits is used where each bit of the bit sequence is associated with an RRH, and the bit value '1' is used to indicate that the RRH is selected and the bit value '0' is used to indicate that the RRH is not selected. For example, a combinatorial index, indicated via
Figure PCTKR2021018843-appb-I000425
bits signaling, is used to indicate
Figure PCTKR2021018843-appb-I000426
RRH selection hypotheses, W1 basis vector selection in Rel. 15 NR Type I codebook.
In another example, this component is combined (joint) with an amplitude component of the codebook, where the amplitude codebook includes a value 0 (in addition to other values greater than 0), and the value '0' is used to indicate/report that the RRH is not selected and the bit value greater than 0 is used to indicate/report that the RRH is selected and the indicated/reported value indicates the amplitude weighting in the precoder equation/calculation.
In one example III.1.4.3, a UE is configured to report the CSI based on the D-MIMO codebook using a two-part UCI, UCI part 1 and UCI part 2, and the UCI part 1 is used indicate/report the RRH selection. In one example, the two-part UCI is configured only when the UE is configured to report the SB CSI reporting based on the D-MIMO codebook. In one example, the two-part UCI is configured only when the UE is configured with the Type II or Type II port selection codebook for D-MIMO.
In one example III.1.4.4, a UE is configured to report the CSI based on the D-MIMO codebook using a two-part UCI, UCI part 1 and UCI part 2, and the UCI part 2 is used indicate/report the RRH selection. In one example, the two-part UCI is configured only when the UE is configured to report the SB CSI reporting based on the D-MIMO codebook. In one example, the two-part UCI is configured only when the UE is configured with the Type II or Type II port selection codebook for D-MIMO.
In one example III.1.4.5, a UE is configured to report the CSI based on the D-MIMO codebook using one-part UCI, which is used indicate/report the RRH selection. In one example, the one-part UCI is configured only when the UE is configured to report the WB CSI reporting based on the D-MIMO codebook. In one example, the one-part UCI is configured only when the UE is configured with the Type I codebook for D-MIMO.
In one example, a UE is configured with a two-part UCI (part 1 and part 2) for CSI reporting based on D-MIMO codebook.
Figure PCTKR2021018843-appb-I000427
In one example, UCI part 1 includes the information about the RRH selection.
Figure PCTKR2021018843-appb-I000428
In one example, UCI part 1 includes the information the strongest RRH.
Figure PCTKR2021018843-appb-I000429
In one example, UCI part 1 includes both the information the strongest RRH and the information about the RRH selection.
Figure PCTKR2021018843-appb-I000430
In one example, UCI part 2 includes the information about the RRH selection.
Figure PCTKR2021018843-appb-I000431
In one example, UCI part 2 includes the information the strongest RRH.
Figure PCTKR2021018843-appb-I000432
In one example, UCI part 2 includes both the information the strongest RRH and the information about the RRH selection.
In one example, a UE is configured with a one-part UCI for RRH selection reporting.
Figure PCTKR2021018843-appb-I000433
In one example, this configuration is restricted to the case when WB CSI reporting is configured (i.e., for SB CSI reporting, two-part UCI is used to report RRH selection).
Figure PCTKR2021018843-appb-I000434
In one example, this configuration is restricted to the case when Type I codebook for D-MIMO is configured (i.e., for Type II codebook, two-part UCI is used to report RRH selection).
In one example, a UE is configured with a one-part UCI for the strongest RRH reporting.
Figure PCTKR2021018843-appb-I000435
In one example, this configuration is restricted to the case when WB CSI reporting is configured (i.e., for SB CSI reporting, two-part UCI is used to report RRH selection).
In one example, this configuration is restricted to the case when Type I codebook for D-MIMO is configured (i.e., for Type II codebook, two-part UCI is used to report RRH selection).
In one example, a UE is configured with a one-part UCI for both RRH selection and the strongest RRH reporting.
Figure PCTKR2021018843-appb-I000436
In one example, this configuration is restricted to the case when WB CSI reporting is configured (i.e., for SB CSI reporting, two-part UCI is used to report RRH selection).
In one example, this configuration is restricted to the case when Type I codebook for D-MIMO is configured (i.e., for Type II codebook, two-part UCI is used to report RRH selection).
In one example, the parameter
Figure PCTKR2021018843-appb-I000437
is fixed, e.g., 2. In one example, the parameter
Figure PCTKR2021018843-appb-I000438
is configured, e.g., via RRC. In one example, the parameter
Figure PCTKR2021018843-appb-I000439
is reported by the UE, e.g., via UCI part 1 of two-part UCI comprising part 1 and part 2. The reported
Figure PCTKR2021018843-appb-I000440
value can be based on a minimum value
Figure PCTKR2021018843-appb-I000441
, i.e., the UE can report any
Figure PCTKR2021018843-appb-I000442
such that
Figure PCTKR2021018843-appb-I000443
. Alternatively, the reported
Figure PCTKR2021018843-appb-I000444
value can be based on a maximum value
Figure PCTKR2021018843-appb-I000445
, i.e., the UE can report any
Figure PCTKR2021018843-appb-I000446
such that
Figure PCTKR2021018843-appb-I000447
. Alternatively, the reported
Figure PCTKR2021018843-appb-I000448
value can be based on a minimum value
Figure PCTKR2021018843-appb-I000449
and a maximum value
Figure PCTKR2021018843-appb-I000450
, i.e., the UE can report any
Figure PCTKR2021018843-appb-I000451
such that
Figure PCTKR2021018843-appb-I000452
. The value
Figure PCTKR2021018843-appb-I000453
or/and
Figure PCTKR2021018843-appb-I000454
can be fixed, or configured (e.g., RRC) or reported by the UE as part of UE capability reporting.
Figure PCTKR2021018843-appb-I000455
In one example, both
Figure PCTKR2021018843-appb-I000456
and indicator indicating selected RRHs are reported via UCI part 1.
Figure PCTKR2021018843-appb-I000457
In one example,
Figure PCTKR2021018843-appb-I000458
is reported via UCI part 1, and indicator indicating selected RRHs is reported via UCI part 2.
In this disclosure, the codebook component
Figure PCTKR2021018843-appb-I000459
refers to pre-coder (or pre-coding matrix) components that are indicated via the components of the first PMI indicator
Figure PCTKR2021018843-appb-I000460
. Likewise, the codebook component
Figure PCTKR2021018843-appb-I000461
refers to pre-coder (or pre-coding matrix) components that are indicated via the components of the second PMI indicator
Figure PCTKR2021018843-appb-I000462
. Likewise, the new codebook component
Figure PCTKR2021018843-appb-I000463
refers to pre-coder (or pre-coding matrix) components that are indicated via the components of the third PMI indicator
Figure PCTKR2021018843-appb-I000464
.
In one embodiment IV.1, the codebook for D-MIMO transmission has one of the fowling designs.
In one example IV.1.1, the codebook has a decoupled (separate) design for inter-RRH and intra-RRH components. For example, (Inter-RRH, Intra-RRH) = (Type I, Type I) or (Type II, Type I) or (Type I, Type II), or (Type II, Type II), wherein the Type I implies that the corresponding codebook components has similarity with Rel. 15 NR Type I codebook, and likewise, Type II implies that the corresponding codebook components has similarity with Rel. 15 or 16 NR Type II codebook.
In one example IV.1.2, the codebook has a coupled (joint) design for inter-RRH and intra-RRH components. For example, (Inter-RRH, Intra-RRH) has a Type I or Type II like design.
In one embodiment IV.2, the
Figure PCTKR2021018843-appb-I000465
components have one of the following high-level design.
In one example IV.2.1, the
Figure PCTKR2021018843-appb-I000466
components have Type I structure. In one example, only
Figure PCTKR2021018843-appb-I000467
or
Figure PCTKR2021018843-appb-I000468
is used in
Figure PCTKR2021018843-appb-I000469
, i.e., only one beam or basis vector is used for each layer (or precoder for each layer). In one example,
Figure PCTKR2021018843-appb-I000470
or
Figure PCTKR2021018843-appb-I000471
(e.g., 4) is used in
Figure PCTKR2021018843-appb-I000472
, i.e., multiple beams or basis vectors are included in
Figure PCTKR2021018843-appb-I000473
, but the UE selects one beam or basis vector out of
Figure PCTKR2021018843-appb-I000474
beams for each layer (or precoder for each layer). In one example, the UE is configured with either
Figure PCTKR2021018843-appb-I000475
or
Figure PCTKR2021018843-appb-I000476
in
Figure PCTKR2021018843-appb-I000477
, and the UE selects/reports
Figure PCTKR2021018843-appb-I000478
accordingly.
Figure PCTKR2021018843-appb-I000479
Design 1:
o Single panel: cross-pol co-phase, inter-RRH phase
o Multi-panel: cross-pol co-phase, inter-panel phase, inter-RRH phase
Figure PCTKR2021018843-appb-I000480
Design 2:
o Single panel: a joint co-phase
o Multi-panel: at least two or all of cross-pol co-phase, inter-panel phase, inter-RRH phase are joint
In one example IV.2.2, the
Figure PCTKR2021018843-appb-I000481
components has Type II structure. In one example,
Figure PCTKR2021018843-appb-I000482
, and the value of
Figure PCTKR2021018843-appb-I000483
is configured (e.g., via RRC signaling) from a set of supported values. In one example, the set of supported values belongs to
Figure PCTKR2021018843-appb-I000484
.
Figure PCTKR2021018843-appb-I000485
Design 1:
o separate amplitude components for polarizations or/and panels or/and RRHs
Figure PCTKR2021018843-appb-I000486
Design 2:
o joint amplitude
In one embodiment IV.3, the D-MIMO codebook includes both coherent and non-coherent pre-coders, wherein a coherent pre-coder corresponds to a precoder or pre-coding matrix whose all entries all non-zero, and a non-coherent pre-coder corresponds to a precoder or pre-coding matrix who's each row or each column has at least one zero entry.
Any of the above variation embodiments can be utilized independently or in combination with at least one other variation embodiment.
FIGURE 16 illustrates a flow chart of a method 1600 for operating a user equipment (UE), as may be performed by a UE such as UE 116, according to embodiments of the present disclosure. The embodiment of the method 1600 illustrated in FIGURE 16 is for illustration only. FIGURE 18 does not limit the scope of this disclosure to any particular implementation.
As illustrated in FIGURE 16, the method 1600 begins at step 1602. In step 1602, the UE (e.g., 111-116 as illustrated in FIGURE 1) receives information about a channel state information (CSI) report, the information including a number
Figure PCTKR2021018843-appb-I000487
> 1 and RRH
Figure PCTKR2021018843-appb-I000488
, wherein:
Figure PCTKR2021018843-appb-I000489
= number of remote radio heads (RRHs), RRH
Figure PCTKR2021018843-appb-I000490
comprises a group of
Figure PCTKR2021018843-appb-I000491
channel state information reference signal (CSIRS) antenna ports, and r = 1, . . . ,
Figure PCTKR2021018843-appb-I000492
.
In step 1604, the UE selects a strongest RRH from the
Figure PCTKR2021018843-appb-I000493
RRHs.
In step 1606, the UE determines the CSI report including an indicator indicating the strongest RRH.
In step 1608, the UE transmits the CSI report including the indicator indicating the strongest RRH.
In one embodiment, for each RRH
Figure PCTKR2021018843-appb-I000494
, the information includes an information about
Figure PCTKR2021018843-appb-I000495
.
In one embodiment,
Figure PCTKR2021018843-appb-I000496
and the information about
Figure PCTKR2021018843-appb-I000497
corresponds to a value of
Figure PCTKR2021018843-appb-I000498
.
In one embodiment, the strongest RRH is reported as either wideband (WB) or subband (SB), where WB corresponds to a single value that is common for all subbands in a CSI reporting band and SB corresponds to multiple values, one value for each subband in the CSI reporting band.
In one embodiment, the strongest RRH is reported as either layer-common or layer-specific, where the layer-common corresponds to a single value that is common for all layers and the layer-specific corresponds to multiple values, one value for each layer.
In one embodiment, an amplitude associated with the strongest RRH = 1.
In one embodiment, the UE determines the CSI report including an indicator indicating an RRH selection in which
Figure PCTKR2021018843-appb-I000499
out of the
Figure PCTKR2021018843-appb-I000500
RRHs are selected, wherein the CSI report is determined for the selected
Figure PCTKR2021018843-appb-I000501
out of the
Figure PCTKR2021018843-appb-I000502
RRHs, and
Figure PCTKR2021018843-appb-I000503
.
In one embodiment, the indicator indicating the RRH selection is a bit sequence
Figure PCTKR2021018843-appb-I000504
of length
Figure PCTKR2021018843-appb-I000505
, where
Figure PCTKR2021018843-appb-I000506
indicates RRH
Figure PCTKR2021018843-appb-I000507
not selected, and
Figure PCTKR2021018843-appb-I000508
indicates RRH
Figure PCTKR2021018843-appb-I000509
being selected.
In one embodiment, the indicator indicating the RRH selection is a
Figure PCTKR2021018843-appb-I000510
bit combinatorial indicator, wherein
Figure PCTKR2021018843-appb-I000511
is a ceiling function.
In one embodiment, the indicator indicating the RRH selection indicates an amplitude value (
Figure PCTKR2021018843-appb-I000512
) for each RRH, where
Figure PCTKR2021018843-appb-I000513
indicates that RRH
Figure PCTKR2021018843-appb-I000514
is not selected, and
Figure PCTKR2021018843-appb-I000515
indicates that RRH
Figure PCTKR2021018843-appb-I000516
is selected.
In one embodiment, the RRH selection is reported as either layer-common or layer-specific, where the layer-common corresponds to a single value that is common for all layers and the layer-specific corresponds to multiple values, one value for each layer.
In one embodiment, the UE transmits the CSI report via a two-part uplink control information (UCI) comprising part 1 and part 2, and UCI part 1 includes information about the RRH selection.
FIGURE 17 illustrates a flow chart of another method 1700, as may be performed by a base station (BS) such as BS 102, according to embodiments of the present disclosure. The embodiment of the method 1700 illustrated in FIGURE 17 is for illustration only. FIGURE 17 does not limit the scope of this disclosure to any particular implementation.
As illustrated in FIGURE 17, the method 1700 begins at step 1702. In step 1702, the BS (e.g., 101-103 as illustrated in FIGURE 1), generates information about a channel state information (CSI) report, the information including a number
Figure PCTKR2021018843-appb-I000517
> 1 and RRH
Figure PCTKR2021018843-appb-I000518
, wherein:
Figure PCTKR2021018843-appb-I000519
=number of remote radio heads (RRHs), RRH
Figure PCTKR2021018843-appb-I000520
comprises a group of
Figure PCTKR2021018843-appb-I000521
channel state information reference signal (CSIRS) antenna ports, and r = 1, . . . ,
Figure PCTKR2021018843-appb-I000522
.
In step 1704, the BS transmits the information.
In step 1706, the BS receives the CSI report, wherein the CSI report includes an indicator indicating a strongest RRH selected from the
Figure PCTKR2021018843-appb-I000523
RRHs.
In one embodiment, for each RRH
Figure PCTKR2021018843-appb-I000524
, the information includes an information about
Figure PCTKR2021018843-appb-I000525
.
In one embodiment,
Figure PCTKR2021018843-appb-I000526
and the information about
Figure PCTKR2021018843-appb-I000527
corresponds to a value of
Figure PCTKR2021018843-appb-I000528
.
In one embodiment, the strongest RRH is reported as either wideband (WB) or subband (SB), where WB corresponds to a single value that is common for all subbands in a CSI reporting band and SB corresponds to multiple values, one value for each subband in the CSI reporting band.
The above flowcharts illustrate example methods that can be implemented in accordance with the principles of the present disclosure and various changes could be made to the methods illustrated in the flowcharts herein.  For example, while shown as a series of steps, various steps in each figure could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps may be omitted or replaced by other steps.
Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims. None of the description in this application should be read as implying that any particular element, step, or function is an essential element that must be included in the claims scope. The scope of patented subject matter is defined by the claims.

Claims (15)

  1. A user equipment (UE) comprising:
    a transceiver configured to receive information about a channel state information (CSI) report, the information including a number
    Figure PCTKR2021018843-appb-I000529
    > 1 and RRH
    Figure PCTKR2021018843-appb-I000530
    , wherein:
    Figure PCTKR2021018843-appb-I000531
    =number of remote radio heads (RRHs),
    RRH
    Figure PCTKR2021018843-appb-I000532
    comprises a group of
    Figure PCTKR2021018843-appb-I000533
    channel state information reference signal (CSIRS) antenna ports, and
    r = 1, . . . ,
    Figure PCTKR2021018843-appb-I000534
    ; and
    a processor operably coupled to the transceiver, the processor, based on the information, configured to:
    select a strongest RRH from the
    Figure PCTKR2021018843-appb-I000535
    RRHs; and
    determine the CSI report including an indicator indicating the strongest RRH;
    wherein the transceiver is configured to transmit the CSI report including the indicator indicating the strongest RRH.
  2. The UE of Claim 1, wherein for each RRH
    Figure PCTKR2021018843-appb-I000536
    , the information includes an information about
    Figure PCTKR2021018843-appb-I000537
    , andwherein
    Figure PCTKR2021018843-appb-I000538
    and the information about
    Figure PCTKR2021018843-appb-I000539
    corresponds to a value of
    Figure PCTKR2021018843-appb-I000540
    .
  3. The UE of Claim 1, wherein the strongest RRH is reported as either wideband (WB) or subband (SB), where WB corresponds to a single value that is common for all subbands in a CSI reporting band and SB corresponds to multiple values, one value for each subband in the CSI reporting band.
  4. The UE of Claim 1, wherein the strongest RRH is reported as either layer-common or layer-specific, where the layer-common corresponds to a single value that is common for all layers and the layer-specific corresponds to multiple values, one value for each layer.
  5. The UE of Claim 1, wherein an amplitude associated with the strongest RRH = 1.
  6. The UE of Claim 1, wherein the processor is further configured to determine the CSI report including an indicator indicating an RRH selection in which
    Figure PCTKR2021018843-appb-I000541
    out of the
    Figure PCTKR2021018843-appb-I000542
    RRHs are selected, wherein the CSI report is determined for the selected
    Figure PCTKR2021018843-appb-I000543
    out of the
    Figure PCTKR2021018843-appb-I000544
    RRHs, and
    Figure PCTKR2021018843-appb-I000545
    .
  7. The UE of Claim 6, wherein the indicator indicating the RRH selection is a bit sequence
    Figure PCTKR2021018843-appb-I000546
    of length
    Figure PCTKR2021018843-appb-I000547
    , where
    Figure PCTKR2021018843-appb-I000548
    indicates RRH
    Figure PCTKR2021018843-appb-I000549
    not selected, and
    Figure PCTKR2021018843-appb-I000550
    indicates RRH
    Figure PCTKR2021018843-appb-I000551
    being selected.
  8. The UE of Claim 6, wherein the indicator indicating the RRH selection is a
    Figure PCTKR2021018843-appb-I000552
    bit combinatorial indicator, wherein
    Figure PCTKR2021018843-appb-I000553
    is a ceiling function.
  9. The UE of Claim 6, wherein the indicator indicating the RRH selection indicates an amplitude value (
    Figure PCTKR2021018843-appb-I000554
    ) for each RRH, where
    Figure PCTKR2021018843-appb-I000555
    indicates that RRH
    Figure PCTKR2021018843-appb-I000556
    is not selected, and
    Figure PCTKR2021018843-appb-I000557
    indicates that RRH
    Figure PCTKR2021018843-appb-I000558
    is selected.
  10. The UE of Claim 6, wherein the RRH selection is reported as either layer-common or layer-specific, where the layer-common corresponds to a single value that is common for all layers and the layer-specific corresponds to multiple values, one value for each layer.
  11. The UE of Claim 6, wherein the transceiver is configured to transmit the CSI report via a two-part uplink control information (UCI) comprising part 1 and part 2, and UCI part 1 includes information about the RRH selection.
  12. A base station (BS) comprising:
    a processor configured to generate information about a channel state information (CSI) report, the information including a number
    Figure PCTKR2021018843-appb-I000559
    > 1 and RRH
    Figure PCTKR2021018843-appb-I000560
    , wherein:
    Figure PCTKR2021018843-appb-I000561
    =number of remote radio heads (RRHs),
    RRH
    Figure PCTKR2021018843-appb-I000562
    comprises a group of
    Figure PCTKR2021018843-appb-I000563
    channel state information reference signal (CSIRS) antenna ports, and
    r = 1, . . . ,
    Figure PCTKR2021018843-appb-I000564
    ; and
    a transceiver operably coupled to the processor, the transceiver configured to:
    transmit the information; and
    receive the CSI report,
    wherein the CSI report includes an indicator indicating a strongest RRH selected from the
    Figure PCTKR2021018843-appb-I000565
    RRHs.
  13. The BS of Claim 12, wherein for each RRH
    Figure PCTKR2021018843-appb-I000566
    , the information includes an information about
    Figure PCTKR2021018843-appb-I000567
    , and
    wherein
    Figure PCTKR2021018843-appb-I000568
    and the information about
    Figure PCTKR2021018843-appb-I000569
    corresponds to a value of
    Figure PCTKR2021018843-appb-I000570
    .
    wherein the strongest RRH is reported as either wideband (WB) or subband (SB), where WB corresponds to a single value that is common for all subbands in a CSI reporting band and SB corresponds to multiple values, one value for each subband in the CSI reporting band.
  14. A method for operating a user equipment (UE), the method comprising:
    receiving information about a channel state information (CSI) report, the information including a number
    Figure PCTKR2021018843-appb-I000571
    > 1 and RRH
    Figure PCTKR2021018843-appb-I000572
    , wherein:
    Figure PCTKR2021018843-appb-I000573
    =number of remote radio heads (RRHs),
    RRH
    Figure PCTKR2021018843-appb-I000574
    comprises a group of
    Figure PCTKR2021018843-appb-I000575
    channel state information reference signal (CSIRS) antenna ports, and
    r = 1, . . . ,
    Figure PCTKR2021018843-appb-I000576
    ;
    selecting a strongest RRH from the
    Figure PCTKR2021018843-appb-I000577
    RRHs;
    determining the CSI report including an indicator indicating the strongest RRH; and
    transmitting the CSI report including the indicator indicating the strongest RRH.
  15. A method for operating a base station (BS), the method comprising:
    generating information about a channel state information (CSI) report, the information including a number
    Figure PCTKR2021018843-appb-I000578
    > 1 and RRH
    Figure PCTKR2021018843-appb-I000579
    , wherein:
    Figure PCTKR2021018843-appb-I000580
    =number of remote radio heads (RRHs),
    RRH
    Figure PCTKR2021018843-appb-I000581
    comprises a group of
    Figure PCTKR2021018843-appb-I000582
    channel state information reference signal (CSIRS) antenna ports, and
    r = 1, . . . ,
    Figure PCTKR2021018843-appb-I000583
    ; and
    transmitting the information; and
    receiving the CSI report,
    wherein the CSI report includes an indicator indicating a strongest RRH selected from the
    Figure PCTKR2021018843-appb-I000584
    RRHs.
PCT/KR2021/018843 2020-12-14 2021-12-13 Codebook for distributed mimo transmission WO2022131713A1 (en)

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