[Invention Title]

HIGH-RESOLUTION CSI REPORTING BASED ON UNEQUAL BIT ALLOCATION IN ADVANCED WIRELESS COMMUNICATION SYSTEMS

[Technical Field]

[0001] The present disclosure relates generally to CSI reporting schemes based on an unequal bit allocation in advanced wireless communication systems.

[Background Art]

[0002] 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 (MIM0) , Full Dimensional MIM0 (FD-MIM0) , 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. [0003] 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 informat ion wi thout 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 implementat ion, 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 1 ife by col lecting 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.

[0004] In 1 ine with this , var ious attempts have been made to apply 5G communi cat ion 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, MIM0, 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.

[0005] Understanding and correctly estimating the channel in an advance wireless communication system between a user equipment (UE) and an eNode B (eNB) is important for efficient and effective wireless communication. In order to correctly estimate the channel conditions, the UE may report (e.g., feedback) information about channel measurement, e.g., CSI, to the eNB. With this information about the channel, the eNB is able to select appropriate communication parameters to efficiently and effectively perform wireless data communication with the UE.

[Disclosure]

[Technical Problem]

[0006] However, with increase in the numbers of antennas and channel paths of wireless communication devices, so too has the amount of feedback increased that may be needed to ideal ly est imate the channel. This additionally-desired channel feedback may create additional overheads, thus reducing the efficiency of the wireless communication, for example, decrease the data rate.

[Technical Solution]

[0007] Embodiments of the present disclosure provide methods and apparatuses for CSI reporting schemes based on an unequal bit allocation in an advanced wireless communication system.

[0008] In one embodiment, a UE is provided. The UE includes a processor configured to generate a report for a precoding matrix indicator (PMI). The report includes (i) a wideband ampl itude coefficient indicator that is common for a plural ity of subbands configured for reporting and (ii) a subband amplitude coefficient indicator and a subband phase coefficient indicator for each of the subbands. The UE further includes a transceiver operably connected to the processor. The transceiver is configured to transmit the generated report for the PMI to a base stat ion.

[0009] In another embodiment, a base station (BS) is provided. The BS includes a transceiver configured to receive a report for a PMI. The report includes (i) a wideband amplitude coefficient indicator that is common for a plurality of subbands configured for reporting and (ii) a subband amplitude coefficient indicator and a subband phase coefficient indicator for each of the subbands. The BS also includes a processor operably connected to the transceiver.

[0010] In yet another embodiment, a method for report ing a PMI by a UE is provided

The method includes generating a report for a PMI. The report includes (i) a wideband amplitude coefficient indicator that is common for a plurality of subbands configured for reporting and (ii) a subband amplitude coefficient indicator and a subband phase coefficient indicator for each of the subbands. The method further includes transmitting the generated report for the PMI to a base station.

(0011] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

[Advantageous Effects!

[0012] According to embodiments of the invention, CSI report ing procedures can be efficiently performed and thereby signal ing overhead can be reduced and efficiency of data rate can be achieved.

[Description of Drawings]

[0013] 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 1 ike reference numerals represent 1 ike parts:

[0014] FIGURE 1 i 1 lustrates an example wireless network according to embodiments of the present disclosure;

[0015] FIGURE 2 illustrates an example eNB according to embodiments of the present disclosure;

[0016] FIGURE 3 i 1 lustrates an example UE according to embodiments of the present disclosure;

[0017] FIGURE 4A illustrates a high-level diagram of an orthogonal frequency division multiple access transmit path according to embodiments of the present disclosure; [0018] FIGURE 4B illustrates a high-level diagram of an orthogonal frequency division multiple access receive path according to embodiments of the present disclosure;

[0019] FIGURE 5 i 1 lustrates a transmi tter block diagram for a PDSCH in a subframe according to embodiments of the present disclosure!

[0020] FIGURE 6 illustrates a receiver block diagram for a PDSCH in a subframe according to embodiments of the present disclosure;

[0021] FIGURE 7 i 1 lustrates a transmitter block diagram for a PUSCH in a subframe according to embodiments of the present disclosure;

[0022] FIGURE 8 illustrates a receiver block diagram for a PUSCH in a subframe according to embodiments of the present disclosure;

[0023] FIGURE 9 illustrates an example multiplexing of two slices according to embodiments of the present disclosure!

[0024] FIGURE 10 illustrates an example antenna blocks according to embodiments of the present disclosure!

[0025] FIGURE 11 illustrates an example network configuration according to embodiments of the present disclosure!

[0026] FIGURE 12 illustrates an example 2D antenna port layout according to embodiments of the present disclosure! and

[0027] FIGURE 13 illustrates a flowchart of a method for PMI report ing according to embodiments of the present disclosure.

[Mode for Invention]

[0028] Before undertaking the DETAILED DESCRIPTION, 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 we 11 as derivat ives thereof , mean inclusion wi thout 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 operat ion. Such a control ler 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.

[0029] 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.

[0030] 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.

[0031] FIGURES 1 through FIGURE 13, 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 ski 1 led in the art wi 11 understand that the principles of the present disclosure may be implemented in any suitably arranged system or device. 10032] 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 vl4.2.0, "E-UTRA, Physical channels and modulation;" 3GPP TS 36.212 vU.2.0, "E-UTRA, Multiplexing and Channel coding;" 3GPP TS 36.213 vl4.2.0,

"E-UTRA, Physical Layer Procedures;" 3GPP TS 36.321 vl4.2.0, "E-UTRA, Medium Access Control (MAC) protocol specification;" 3GPP TS 36.331 vl4.2.0, "E-UTRA , Radio Resource Control (RRC) protocol specification" and 3GPP TR 22.891 vl.2.0,

"Feasibility Study on New Services and Markets Technology Enablers."

[0033] Aspects, features, and advantages of the disclosure are readily apparent from the fol lowing detai led descr ipt ion, simply by i 1 lustrat ing a number of part icular embodiments and implementations, including the best mode contemplated for carrying out the disclosure. The disclosure is also capable of other and di fferent 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.

[0034] In the following, for brevity, both FDD and TDD are considered as the duplex method for both DL and UL signaling.

[0035] Although exemplary descriptions and embodiments to follow assume orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (0FDMA), this disclosure can be extended to other OFDM-based transmission waveforms or multiple access schemes such as filtered OFDM (F-OFDM).

[0036] The present disclosure covers several components which can be used in conjunct ion or in combinat ion with one another , or can operate as standalone schemes .

[0037] 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."

[0038] 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 coverage, the beamforming, massive multiple-input multiple-output (MIM0) , full dimensional MIM0 (FD-MIM0), array antenna, an analog beam forming, large scale antenna techniques and the like are discussed in 5G communication systems.

[0039] In addition, in 5G communi cat ion 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 communication, moving network, cooperative communication, coordinated multi-points (CoMP) transmission and reception, interference mitigation and cancellation and the like.

[0040] In the 5G system, hybrid frequency shift keying and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) as an adaptive modulation and coding (AMC) technique, 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.

[0041] FIGURES 1-4B below describe various embodiments implemented in wireless communicat ions systems and with the use of orthogonal frequency division mult iplexing (OFDM) or orthogonal frequency division multiple access (0FDMA) 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.

[0042] FIGURE 1 i 1 lustrates 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.

[0043] As shown in FIGURE 1, the wireless network includes an eNB 101, an eNB

102, and an eNB 103. The eNB 101 communicates with the eNB 102 and the eNB 103. The eNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0044] The eNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipments (UEs) within a coverage area 120 of the eNB 102. The first plural i ty of UEs includes a UE 111, which may be located in a smal 1 business (SB); a UE 112, which may be located in an enterprise (E) ; a UE 113, which may be located in a WiFi hotspot (HS); a UE 114, which may be located in a first residence (R); a UE 115, which may be located in a second residence (R); and a UE 116, which may be a mobile device (M) , such as a cell phone, a wireless laptop, a wireless PDA, or the like. The eNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the eNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more of the eNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G, LTE, LTE-A, WiMAX, WiFi , or other wireless communication techniques.

[0045] 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. lla/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).

[0046] 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 eNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending upon the configuration of the eNBs and variations in the radio environment associated with natural and man-made obstructions.

[0047] As described in more detail below, one or more of the UEs 111-116 include circuitry, programing, or a combination thereof, for efficient CSI reporting in an advanced wireless communication system. In certain embodiments, and one or more of the eNBs 101-103 includes circuitry, programing, or a combination thereof, for receiving efficient CSI reporting for a PMI based on unequal bit allocation in an advanced wireless communication system.

[0048] 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 eNBs and any number of UEs in any suitable arrangement. Also, the eNB 101 could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network 130. Similarly, each eNB 102-103 could communicate directly with the network 130 and provide UEs with direct wireless broadband access to the network 130. Further, the eNBs 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.

[0049] FIGURE 2 illustrates an example eNB 102 according to embodiments of the present disclosure. The embodiment of the eNB 102 illustrated in FIGURE 2 is for illustration only, and the eNBs 101 and 103 of FIGURE 1 could have the same or similar configuration. However, eNBs come in a wide variety of configurations, and FIGURE 2 does not limit the scope of this disclosure to any particular implementation of an eNB.

[0050] As shown in FIGURE 2, the eNB 102 includes multiple antennas 205a-205n, multiple RF transceivers 210a-210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. The eNB 102 also includes a controller/processor 225, a memory 230, and a backhaul or network interface 235.

[0051] 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.

[0052] 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.

[0053] The controller/processor 225 can include one or more processors or other processing devices that control the overall operation of the eNB 102. For example, the controller/processor 225 could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 in accordance with well-known principles. The controller/processor 225 could support additional functions as well, such as more advanced wireless communication functions.

[0054] 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 eNB 102 by the controller/processor 225.

[0055] 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.

[0056] The controller/processor 225 is also coupled to the backhaul or network interface 235. The backhaul or network interface 235 allows the eNB 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 connect ion(s) . For example, when the eNB 102 is implemented as part of a cellular communication system (such as one supporting 5G, LTE, or LTE-A) , the interface 235 could al low the eNB 102 to communicate with other eNBs over a wired or wireless backhaul connection. When the eNB 102 is implemented as an access point, the interface 235 could allow the eNB 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.

[0057] 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.

[0058] Although FIGURE 2 illustrates one example of eNB 102, various changes may be made to FIGURE 2. For example, the eNB 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 eNB 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.

[0059] 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.

[0060] 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 (1/0) 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.

[0061] The RF transceiver 310 receives, from the antenna 305, an incoming RF signal transmitted by an eNB 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).

[0062] 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.

[0063] 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 overal 1 operation of the UE 116. For example, the processor 340 could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver 310, the RX processing circuitry 325, and the TX processing circuitry 315 in accordance wi th wel 1-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller. ^'

[0064] The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as processes for CSI reporting for a PMI based on unequal bit allocation. 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 eNBs or an operator. The processor 340 is also coupled to the 1/0 interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. The 1/0 interface 345 is the communication path between these accessories and the processor 340.

[0065] 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 1 iquid crystal display, 1 ight emitting diode display, or other display capable of rendering text and/or at least limited graphics, such as from web sites.

[0066] 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). [0067] 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.

[0068] 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 (0FDMA) 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 (0FDMA) communication. In FIGURES 4A and 4B, for downlink communication, the transmit path circuitry may be implemented in a base station (eNB) 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. eNB 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).

[0069] 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. [0070] 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 im lementation.

[0071] 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 Four ier 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.).

[0072] 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 (QPS ) 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 paral lei data to produce N paral lei 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 F frequency for transmission via a wireless channel. The signal may also be filtered at baseband before conversion to RF frequency.

[0073] The transmitted RF signal arrives at UE 116 after passing through the wireless channel, and reverse operations to those at eNB 102 are performed. Down-converter 455 down-converts the received signal to baseband frequency, and remove cyclic prefix block 460 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 demodulat ion block 480 demodulates and then decodes the modulated symbols to recover the original input data stream.

[0074] Each of eNBs 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 eNBs 101-103 and may implement a receive path corresponding to the architecture for receiving in the downlink from eNBs 101-103.

[0075] 5G communication system use cases have been identified and described.

Those use cases can be roughly categorized into three different groups. In one example, enhanced mobi le broadband (eMBB) is determined to do with high bits/sec requirement, with less stringent latency and reliability requirements. In another example, ultra reliable and low latency (URLL) is determined with less stringent bits/sec requirement . In yet another example, massive machine type communication (mMTC) is determined that a number of devices can be as many as 100,000 to 1 million per km2, but the reliability/throughput/latency requirement could be less stringent. This scenario may also involve power efficiency requirement as well ,in that the battery consumpt ion may be minimized as possible.

[0076] A communicat ion system includes a downlink (DL) that conveys signals from transmission points such as BSs or NodeBs to UEs and an Upl ink (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.

[0077] 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).

[0078] 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.

[0079] 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 Informat ion 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.

[0080] 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 _PDSCH RBs for a total of REs

for the PDSCH transmission BW.

[0081] 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 informat ion 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, indicat ing 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 aUE. HARQ-ACK information is also transmitted by a UE in response to a detection of a PDCCH/EPDCCH indicating a release of semi-persi stent ly scheduled PDSCH.

[0082] 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 mult iplex

SRS transmissions from one or moreUEs. A number of subframe symbols that are available for data/UCI/DMRS transmission is where N _SRS = 1 if a last

subframe symbol is used to transmit SRS and N _SRS = 0 otherwise.

[0083] 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 i 1 lustrated in FIGURE 5 is for i 1 lustrat ion only. FIGURE 5 does not limit the scope of this disclosure to any particular implementation of the transmitter block diagram 500.

[0084] 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 appl ies an Inverse fast Fourier transform (IFFT) , the output is then serial ized by a paral lei to serial (P/S) converter 570 to create a time domain signal , fi Iter ing is appl ied by f i Iter 580, and a signal transmitted 590. Addi t ional 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.

[0085] FIGURE 6 i 1 lustrates 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. FIGURE 6 does not limit the scope of this disclosure to any particular implementation of the diagram 600.

[0086] As shown in FIGURE 6, a received signal 610 is filtered by filter 620,

REs 630 for an assigned recept ion BW are selected by BW selector 635, unit 640 appl ies 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.

[0087] 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. FIGURE 7 does not limit the scope of this disclosure to any particular implementation of the block diagram 700.

[0088] 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. [0089] FIGURE 8 i 1 lustrates 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 i 1 lustrated in FIGURE 8 is for i 1 lustrat ion only. FIGURE 8 does not 1 imit the scope of this disclosure to any particular implementation of the block diagram 800.

[0090] 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.

[0091] 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, 745G use cases has been identified and described; those use cases can be roughly categorized into three different groups. A first group is termed 'enhanced mobi le 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 km with less stringent the reliability, data rate, and latency requirements.

[0092] In order for the 5G network to support such diverse services with different quality of services (QoS) , one method has been identified in LTE specification, called network slicing. To utilize PHY resources efficiently and multiplex various slices (with different resource allocation schemes, numerologies , and scheduling strategies) in DL-SCH, a flexible and self-contained frame or subframe design is ut i 1 ized.

[0093] FIGURE 9 illustrates an example multiplexing of two slices 900 according to embodiments of the present disclosure. The embodiment of the multiplexing of two slices 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 multiplexing of two slices 900.

[0094] Two exemplary instances of multiplexing two slices within a common subframe or frame are depicted in FIGURE 9. In these exemplary embodiments, a slice can be composed of one or two transmission instances where one transmission instance includes a control (CTRL) component (e.g., 920a, 960a, 960b, 920b, or 960c) and a data component (e.g., 930a, 970a, 970b, 930b, or 970c). In embodiment 910, the two slices are multiplexed in frequency domain whereas in embodiment 950, the two slices are multiplexed in time domain. These two slices can be transmitted with different sets of numerology.

[0095] LTE specification supports up to 32 CSI-RS antenna ports which enable an eNB to be equipped with a large number of antenna elements (such as 64 or 128). In this case, a plurality of antenna elements is mapped onto one CSI-RS port. For next generation cellular systems such as 5G, the maximum number of CSI-RS ports can either remain the same or increase.

[0096] FIGURE 10 illustrates an example antenna blocks 1000 according to embodiments of the present disclosure. The embodiment of the antenna blocks 1000 i 1 lustrated in FIGURE 10 is for i 1 lustrat ion only. FIGURE 10 does not 1 imi t the scope of this disclosure to any particular implementation of the antenna blocks 1000.

[0097] 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 10. 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. One CSI-RS port can then correspond to one sub-array which produces a narrow analog beam through analog beamforming. This analog beam can be configured to sweep across a wider range of angles 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 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.

[0098] FIGURE 11 illustrates an example network configuration 1100 according to embodiments of the present disclosure. The embodiment of the network configuration 1100 illustrated in FIGURE 11 is for i 1 lustrat ion only . FIGURE 11 does not limit the scope of this disclosure to any particular implementation of the block diagram 100.

[0099] In order for the 5G network to support such diverse services with different quality of services (QoS) , one scheme has been identified in LTE specification, called network slicing.

[0100] As shown in FIGURE 11, An operator' s network 1110 includes a number of radio access network(s) 1120 (RAN(s)) that are associated with network devices such as eNBs 1130a and 1130b, small cell base stations (femto/pico eNBs or Wi-Fi access points) 1135a and 1135b. The network 1110 can support various services, each represented as a slice.

[0101] In the example, an URLL slice 1140a serves UEs requiring URLL services such as cars 1145b, trucks 1145c, smart watches 1145a, and smart glasses 1145d. Two mMTC slices 1150a and 550b serve UEs requiring mMTC services such as power meters 555b, and temperature control box 1155b. One eMBB slice 1160a serves UEs requiring eMBB services such as cells phones 1165a, laptops 1165b, and tablets 1165c. A device configured with two slices can also be envisioned.

[0102] From LTE specification, MIMO has been identified as an essential feature in order to achieve high system throughput requirements and it will continue to be the same in NR. One of the key components of a MIMO transmission scheme is the accurate CSI acquisition at the eNB (or TRP) . For MU-MIM0, 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.

[0103] For FDD systems, on the other hand, it can be acquired using the CSI-RS transmission from eNB, and CSI acquisition and feedback from UE. In FDD systems, the CSI feedback framework is "implicit" in the form of CQI/PMI/RI derived from a codebook assuming SU transmission from eNB. 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 may be a bottleneck in achieving high MU performance gains. Another issue with implicit feedback is the scalabi lity with larger number of antenna ports at eNB.

[0104] For large number of antenna ports, the codebook design for implicit feedback is quite complicated (for example, in LTE specification, the total number of Class A codebooks = 44), and the designed codebook is not guaranteed to bring just if iable performance benef its in pract ical deployment scenarios (for example, only a small percentage gain can be shown at the most). Realizing aforementioned issues, it has agreed to provide specification support to advanced CSI reporting in LTE specification, which, at the very least, can serve as a good start ing point to design advanced CSI scheme in NR MIMO. Compared to LTE specification, the CSI acquisition for NR MIMO may consider the following additional differentiating factors. [0105] In one example of flexibility CSI reporting framework, CSI reporting in

NR may be flexible to support users with different CSI reporting capabilities. For example, some users may only be capable of reporting implicit CSI in the form of PMI/CQI/RI as in LTE and some other users may be capable of reporting both implicit as well as explicit channel reporting. In addition, UE motilities in NR can range from 0 kmph to 500 kmph. So, CSI report ing framework may be able, to support such diverse use cases and UE capabilities.

[0106] In one example of increased number of antenna ports, inNRMIMO, the number of antenna elements at the eNB can be up to 256, which means that the total number of antenna ports can be more than 32, which is the maximum number of antenna ports supported in LTE eFD-MIMO. Although this can be accommodated with part ial-port CSI-RS mapping where each subset consists of at most 32 ports, the total number of ports across time can be extended to a much larger number. As the number of ports increases, meaningful system gain can only be obtained in a MU-centric system.

[0107] In one example of increased throughput requirement , the system throughput requirements (e.g. for eMBB in NR) is several times more than that for LTE eFD-MIMO. Such high throughput requirements can only met with a mechanism to provide very accurate CSI to the eNB.

[0108] In one example of beamforming, following the trend est abl i shed inFD-MIMO,

NR MIMO system may be beam-formed either cell-specifically or UE-specifically, where the beams can either be of analog (RF) or digital or hybrid type. For such a beam-formed system, a mechanism is needed to obtain accurate beam-forming information at the eNB.

[0109] In one example of unified design, since NR includes both above and below

6 GHz frequency bands, a unified MIMO framework working for both frequency regimes may be preferable.

[0110] 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).

[0111] This disclosure of invention covers several components which can be used in conjunction or in combination with one another, or can operate as standalone schemes .

[0112] 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), transmi t-receive point (TRP), an enhanced base station (eNodeB or eNB) , 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 communicat ion 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. lla/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.

[0113] 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) . [0114] FIGURE 12 illustrates an example 2D antenna port layout 1200 according to embodiments of the present disclosure. The embodiment of the 2D antenna port layout 1200 illustrated in FIGURE 12 is for illustration only. FIGURE 12 does not limit the scope of this disclosure to any particular implementation.

[0115] In the following, it is assumed that N ₁ and N ₂ are the number of antenna ports with the same polarization in the first and second dimensions, respectively. For 2D antenna port layouts, it is determined that N ₁ > 1, N ₂ > 1, and for ID antenna port layouts, it could have N ₁ > 1 and N ₂ = 1 or N ₂ > 1 and ΛΊ = 1. In the rest of the disclosure, ID antenna port layouts with N ₁ > 1 and N ₂ - 1 is considered. The disclosure, however, is applicable to the other ID port layouts with N ₂ > 1 and N ₁ - 1. For a dual-polar ized antenna port layout, the total number of antenna ports is 2 N ₁ N ₂ .

[0116] In one embodiment , a dual-stage W = codebook for high-resolution CSI reporting is provided. In such embodiment , W ₁ codebook is used to select : an orthogonal basis set comprising of uniformly spaced (L ₁ , L ₂ ) DFT beams; L E {2,3,4,6,8} beams freely out of the L ₁ L ₂ DFT beams in a basis set; and/or per layer strongest beam out of L beams and two polarizations. In such instance, L is either (e.g. RRC) configurable or UE reports a preferred L value. This selection is WB or partial band (e.g. a set of SBs). Two examples of basis set sizes are restricted orthogonal basis set in whichL ₁ L ₂ = min(8, N ₁ N ₂ ) and full orthogonal basis set in which L ₁ L ₂ - N ₁ N ₂ , one of the two is either supported in the specification or configured via RRC signalling.

[0117] In such embodiment, W2 codebook is used to combine L beams independent ly per layer with a common Wi beam group, i.e. , the selected L beams are the same for all layers and two polarizations, but strongest beam selection is per layer. The ampl i tude and phase of the combining coef f icients are reported separately where phase is reported per subband (SB) and amplitude is reported wideband (WB) or SB or both WB and SB. The number of SBs can be configured, and a WB report implies a report that is common for all SBs. [0118] In one embodiment , a UE is configured with a high-resolution CSI codebook in which the rank R pre-coding matrix is given by W = where the pre-coding vector for layer / is given by

if the strongest beam corresponds to one polarization, e.g. polarization 0 (or +45); if the strongest beam

corresponds to other polarization, e.g. polarization 1 (or -45); and

[0119] The matrices and vector c, are defined as follows. In one example, basis matrix common to both

polarizations where is one of the L orthogonal DFT beams selected from the

selected basis set, and are corresponding indices

of L beams where is the strongest beam for layer /. Note that for rank R

> 1, the strongest beam can be different for different layers, hence the index of the strongest beam is indicated per layer and this indication is WB.

[0120] In one example, diagonal matrix with diagonal elements each belonging to [0, 1], to indicate WB component of the relative beam power levels across L beams and two polarizations.

[0121] In one example, diagonal matrix with diagonal elements each belonging to [0, 1], to indicate

SB component of the relative beam power levels across L beams and two polarizations.

[0122] In one example, c _t is a 2L x 1 vector w _here

to indicate SB relative phase of coefficients across L beams and two

polarizations. [0123] Note that one of the diagonal elements of and elements of is exactly one which corresponds to the strongest beam whose coefficient (both power and phase) can be assumed to be one in general . Also, i f only WB components of relat ive beam power levels are reported, then is an ident ity matrix (hence not reported).

Likewise, if only SB components of relative beam power levels are reported, then P _u is an identity matrix (hence not reported).

[0124] In the present disclosure, the bit allocation to report amplitudes or beam power levels, relative phase where are

considered. In particular, the focus is on the case in which unequal number of bits are allocated to report

[0125] In the rest of the present disclosure, referred to as

amplitudes of beam combining coefficients or weights. They can also be referred to as beam power levels. Also, can equivalent ly be referred to as

wideband amplitude coefficient, subband amplitude coefficient, and subband phase coefficient, respectively. Likewise, ^can equivalently be referred to

as a first amplitude coefficient and a second amplitude coefficient, respectively.

[0126] In some embodiment 0, a UE is configured with a high-resolution CSI codebook explained above in which at least one of are

quantized as follows. In one example of Sorting, the 2L coefficients per layer are sorted in decreasing order. Let denote amplitudes after

sorting, and denote phase after sorting. Note that since the coefficients can

be normalized with the strongest coefficient (which corresponds to the largest amplitude), the coefficients can be assumed that

1, hence the coefficients are not reported.

[0127] In one example of amp 1 itude quant izat ion, to report amplitude of the /-th sorted coefficient the rat io between sorted ampl itudes ,

is quantized, where where denotes the quantized ratio of sorted

amplitudes. To reconstruct the i-th sorted ampl itude, the mult ipl icat ion

considered, where The quantized ratio can be defined

similarly. Let N is the number of bits to quantize each amplitude. The amplitude quantization codebook is either C ₀ or 6\ which are defined as follows: if N = 0, then

[0128] In one example of phase quantization, to report phase of the i-th sorted coefficient alphabet is considered where K - 0, 1, 2, 3.

[0129] The coefficient sorting information is reported either WB or SB. The reporting can be fixed, for example to WB. Alternatively, the UE is configured with one of WB or SB reporting via 1-bit higher layer RRC or dynamic MAC CE or DCI based signal 1 ing.

[0130] When reported WB, the coeff icient sort ing informat ion is reported either joint ly with at least one WB CSI reports such as RI and WB beam select ion, or separately as an independent WB CSI report. Similarly, when reported SB, the coefficient sorting information is reported either jointly with at least one SB CSI reports such as SB amplitude and SB phase, or separately as an independent SB CSI report.

[0131] Also, the coefficient sorting information is reported either common for all layers or independent per layer. In one scheme, one of the two sorting alternatives is fixed, for example to per layer sorting. Alternatively, the UE is configured with one of the two sorting alternatives via 1-bit higher layer RRC or dynamic MAC CE or DCI based signaling.

[0132] In some embodiments 1, a UE is configured with a high-resolution CSI codebook in which amplitudes for layer / and coefficient / are

quantized according to the aforementioned embodiments 0. In addition, the amplitude sorting is WB according to at least one of the following alternatives. In one example of Alt 1-0, the ampl i tude sort ing is common across two polarizations and common across all layers. For example, for 2-layer CSI reporting, the number of bits to report WB sorting information is For L = 4, this

requires 5 bits. In another example of Alt 1-1, the amplitude sorting is common across two polarizations and independent across all layers. For example, for 2-layer CSI reporting, the number of bits to report WB sorting information is 2 x [log ₂ (L!)l. For L = 4, this requires 10 bits.

[0133] In yet another example of Alt 1-2, the amplitude sorting is independent across two polarizations and common across all layers. For example, for 2-layer CSI reporting, the number of bits to report WB sorting information is where For L = 4, this requires 16 bits.

[0134] In yet another example of Alt 1-3, the amplitude sorting is independent across two polarizations and independent across all layers. For example, for 2-layer CSI reporting, the number of bits to report WB sorting information is

For L = 4, this requires 32 bits.

[0135] The amplitude sorting information is reported either jointly with at least one WB CSI reports such as RI and WB beam selection, or separately as an independent WB CSI report.

[0136] For WB only amplitude reporting or SB only amplitude

reporting, at least the following amplitude sorting methods can be considered. In one method, only one of Alt 1-0 to Alt 1-3 is supported in the specification, e.g. Alt 1-0 or Alt 1-3. In another method, only two of Alt 1-0 to Alt 1-3 are supported in the specification, e.g. Alt 1-0 and Alt 1-3 or Alt 1-0 and Alt 1-2. In yet another method, all of Alt 1-0 to Alt 1-3 is supported in the specification. When multiple alternatives are supported, the UE is either configured with one of them or UE reports a preferred alternative as part the CSI report. [0137] When both WB and SB amplitude are reported, the amplitude

is either: common for both WB and SB amplitude components according to at least one of Alt 1-0 to Alt 1-3; or independent for WB and SB amplitude components according to at least one of Alt 1-0 to Alt 1-3. Note that the sorting information reporting payload is doubled in this case.

[0138] Note that there is no need to report the strongest beam as part of the

WB report since the strongest beam is already included in the amplitude sorting information which is reported WB.

[0139] In sub-embodiment 1-0, the phase sorting follows amplitude sorting.

[0140] Let respectively be the number of bits to quantize WB

(Γ _1Χ ;) and amplitude ratio or amplitude for layer / and

coefficient / as explained in the aforementioned embodiments 0. It is worth noting that the strongest amplitude, can be assumed be 1 and hence not reported,

i.e. 0 bit is assigned to report them.

[0141] In some embodiment 2, 2 layer CSI report ings for simpl icity may be assumed

The embodiment, however, is applicable to more than 2 layers. In such embodiments, the number of bits to quantize the remaining 2L-1 amplitude ratios (for each layer) is according to at least one of the following alternatives.

[0142] In one example of Alt 2-0, it is common for all amplitudes, regardless of the sorting alternative, i.e., a single value for is used for each

layer J and coefficient /. The single value is either fixed, e.g. to 3 bits, or configured via RRC signalling, or UE reports as part of the CSI report (WB report).

[0143] In another example of Alt 2-1, it is independent for all amplitudes, regardless of the sort ing alternat ive. In one instance of Alt 1-0 of ampl i tude sort ing, respectively are used for both amplitude

indices and indices and for all layers l. In one instance of Alt 1-1 of amplitude sorting, for Layer 0, L-l values respectively are used for both amplitude indices i

= 1, ··· , L-1 , and indices In one instance of Alt 1-1 of ampl i tude sort ing, for Layer 1, L-l values respectively are used for

both amplitude indices and indices

[0144] In one instance of Alt 1-2 of amplitude sorting, 2L-1 values respectively are used for amplitude indices and for all layers 1.

[0145] In one instance of Alt 1-3 of amplitude sorting, for Layer values respectively are used for amplitude indices In one instance of Alt 1-3 of amplitude sorting, for Layer values respectively are used for amplitude indices

[0146] The values for are either fixed, e.g. from bits,

or configured via RRC signal ling, or UE reports as part of the CSI report (WB report) .

[0147] In one example of Alt 2-2, amplitudes are partitioned into multiple disjoint sets and each set is assigned a single value for amplitude reporting bits independently. A few examples of two sets are as follows. In one instance of Ex 2-0, the number of sets is 2, where the first set has ampl itudes , and the second set has amplitudes, where M= L or 2L depending on the amplitude

sorting alternatives in the aforementioned embodiment 1.

[0148] In one instance of Ex 2-1, the number of sets is 2, where the first set has L ₁ = L amplitudes that correspond to the stronger L out of 2L coefficients, and the second set has the remaining L ₂ = L amplitudes that correspond to weaker L out of 2L coefficients, where amplitude sorting alternatives 1-2 and 1-3 in the aforementioned embodiments 1 have been assumed. [0149] In one instance of Ex 2-2, /the number of sets is 2, where the first set has all but the weakest amplitude (corresponds to the M-th amplitude), and the second set has the weakest amplitude (the M-th amplitude).

[0150] In one instance of Ex 2-3, the number of sets is 2, where the first set has all but the strongest amplitude (corresponds to the 1 ^st amplitude), and the second set has the strongest amplitude (the 1 ^st amplitude).

[0151] In one instance of Ex 2-4, the number of sets is L corresponding to each of L beams. In case of Alt 1-2 and 1-3, the number of bits for amplitude quantization is common for the two amplitudes corresponding to the same beam.

[0152] In sub-embodiment 2-0, the bit allocation to quantize phase of 2L-\ coefficients follows that to quantize amplitude according to at least one of Alt 2-0 to Alt 2-3.

[0153] Unless stated otherwise, the rest of the present disclosure is about bit allocation alternatives and are applicable to both amplitude and phase quantization. For brevity, only amplitude is mentioned in the following embodiments. Also, the bit allocation alternatives for is explained. The alternatives however

are also applicable for the bit allocation for

[0154] In some embodiments 3, amplitudes or/and phases are partitioned into two disjoint sets according to Alt 2-2 in the aforementioned embodiments 2, where each set has equal number (L) of coefficients, and the following bit allocation is used (for WB amplitude), (for SB amplitude), and

(for SB phase).

[0155] Note that the coefficient indices correspond to the

sorted coefficients. In one example, for the first leading beam or coefficient out of 21 beams or coefficients, i.e., the amplitude and

phase of the leading beam coefficient is not reported, and, e.g. the leading beam coefficient is set to 1, where " leading" can also refer to the coefficient with the largest amplitude (also referred to as the strongest coefficient later in the disclosure). In one example for wideband ampltitude + subband ampltitude reporting:

for the first L-l (out of 2L beams or coefficients)

stronger beams or coefficients, for

the remaining L (out of 2L beams or coefficients) weaker beams or coefficients, i.e.,

[0156] In one exmaple for subband only ampltitude reporting: for all

for the first

L-l (out of 2L beams or coefficients) stronger beams or coefficients, i.e., and/or

= (1,2) for the remaining L (out of 2L beams or coefficients) weaker beams or coefficients, i.e.,

[0157] In one exmaple for wideband only ampltitude reporting: for all

/; and/or (P, Q) , where P,Q = 2 or 3.

[0158] In sub-embodiment 3-0, the bit allocation in the aforementioned embodiments 3 is applicable for all L values.

[0159] In sub-embodiment 3-1, the bit allocation in the aforementioned embodiments 3 is applicable for all L > R, where R = 2 or 3 for example. In this case for L ≤ R, equal bit allocation is used for all coefficients

[0160] In some embodiments 3A, amplitudes or/and phases are partitioned into two disjoint sets according to Alt 2-2 in the aforementioned embodiments 2, where each set has ^number of coefficients, and the following bit allocation is used for

(for WB amplitude), (for SB amplitude), and

(for SB phase). Note that the coefficient indices

correspond to the sorted coefficients.

[0161] In one example for the first leading beam or coefficient out of 2L beams or coefficients,

[0162] In one example for wideband ampltitude + subband ampltitude reporting:

for the first (out of 2L beams or coefficients)

stronger beams or coefficients, i.e., for

the remaining 2L-K (out of 2L beams or coefficients) weaker beams or coefficients, i.e., and/or P= 2 or 3.

[0163] In one example for subband only ampltitude reporting: for all

for the first K ^~ \ (out of 2L beams or coefficients) stronger

beams or coefficients, and/or for the remaining 2L ^~ K (out of 2Z. beams or coefficients) weaker beams or coefficients, i .e. ,

[0164] In one example for wideband only ampltitude reporting: for all i; and/or (P, Q) , where P,Q = 2 or 3.

[0165] A few alternatives for J are as follows: Alt 3A-0: K = 2 for all L; Alt

4, for example 6 or 8; Alt 3A-5: K is configured via higher layer (RRC) signaling; Alt 3A-6: K is configured via MAC CE based signaling; Alt 3A-7: K is configured via DCI (DL-related or UL related) signaling; Alt 3A-8: K value for WB only amplitude reporting is the same as that for WB + SB amplitude reporting and is according to one of Alt 3A-0 to Alt 3A-7; Alt 3A-9: lvalue for WB only amplitude reporting is different from that for WB + SB amplitude reporting, and two different lvalues one each for WB only amplitude reporting and WB+SB amplitude reporting are used according to one of Alt 3A-0 to Alt 3A-7; and Alt 3A-10: K is according to a combination of at least two of Alt 3A-0 through Alt 3A-9.

[0166] In some embodiments 3B, a UE is configured to report wideband amplitude with or without subband amplitude via higher-layer RRC signaling, wherein the bit allocation for (wideband amplitude, subband amplitude, subband phase quantization) with bits is as follows. In one exmple for the leading (strongest)

coefficient (corresponds to /= 0) out of 2Z coef f icients ,

and the leading (strongest) coefficient = 1.

[0167] In one example for wideband + subband ampl i tude report ing:

(3,1) and for the first K-l leading (strongest) coefficients out of the

remaining 2L-1 coefficients (excluding the strongest coefficient), i.e.,

1, ... , K-1; where one of the two lvalues is configured via higher-layer RRC signaling! for the remaining 2L-K (out of 2L-1 coefficients) weaker

coefficients, i.e., and/or K = 2,3, ...2L.

[0168] In one example for wideband-only ampl i tude, i.e.

(3,0) and where one of the two lvalues is configured via higher-layer

RRC signaling; and/or the strongest coefficient out of 2L coefficients is reported per layer in a WB manner.

[0169] In some embodiments 3C, the supported values of L E{2,3,4} and the value of A ^' in the aforementioned embodiment 3B is according to at least one of the following alternatives. In one example of Alt 3C-0, only one fixed value for each value of L; one of the following examples is fixed in the specification: Example 3C-0: K = L for

respectively; and Example 3C-14:

[0170] In one example of Alt 3C-1, multiple lvalues for some or all values of

L and one K value is either configured via RRC signaling or the UE reports a preferred lvalue as a WB report.

[0171] In some embodiments 3D, for wideband + subband amplitude quantization, one of equal bit al locat ion or unequal bit al locat ion is used depending on the lvalue in the aforementioned embodiments 3B and embodiments 3C.

[0172] In one example, if K - 2L, then the equal bit allocaiton is used for both amplitude and phase, and in this case the following amplitude quantization method is used: the leading (strongest) coefficient (corresponds to / = 0) out of 2L coefficients is reported per layer in a WB manner (as a WB report). This requires bits per layer. For L = 4, it is 3 bits for rank 1 and 6 bits for rank 2

CSI reporting; and the amplitude quantization is independent for each of the remaining 2L-\ coefficients (i.e., dependent quantizaiton such as the differential across coefficients as propsoed in the aforementioned embodiments 0 is not used).

[0173] In one example, if K < 2L , one of following amplitude quantization alternatives is used. In one instance of Alt 3D-0, 2L coefficients are reported according to the descending order of the reported WB amplitudes independently for each layer, where the grouping information is reported implicitly with the WB amplitude report. This requires bits per layer. For L = A , it is 16 bits

for rank 1 and 32 bits for rank 2 CSI reporting.

[0174] In one instance of Alt 3D-1, 2L coefficients are grouped in two, where grouping information is reported in a WB manner independently for each layer. In addition, the leading (strongest) coefficient (corresponds to i= 0) is reported (WB report) implicitly or explicitly as the strongest coefficient belonging to the first coefficient group. In such instance, the first group corresponds to K leading (strongest) coefficients out of 2L coefficients. In such instance, the second group corresponds to the remaining coefficients.

[0175] For each layer, this requires bits to report the first group

and bits to report the leading (strongest) coefficient. Note there is no

reporting needed for the second group. For L - 4 and K= 5, it requires 6 bits to report the first group and 3 bits to report the leading coefficient per layer, which is 9 bits in total for rank 1 and 18 bits for rank 2 CSI reporting, respectively.

[0176] In one instance of Alt 3D-2, 2L coefficients are grouped in three, where grouping information is reported in a WB manner independently for each layer. In such instance, the first group corresponds to the leading (strongest) coefficient (corresponds to i = 0) out of 2L coefficients. In such instance, the second group corresponds to K-l leading (strongest) coefficients out of the remaining 2L-1 coefficients (excluding the strongest coefficient) . In such instance, the third group corresponds to the remaining coefficients.

[0177] For each layer, this requires bits to report the leading

(strongest) coefficient and bits to report the first group. Note there

is no reporting needed for the second group. For L = 4 and K = 5, it requires 3 bits to report the leading coefficient per layer and 6 bits to report the first group, which is 9 bits in total for rank 1 and 18 bits for rank 2 CSI reporting, respectively.

[0178] In one example of Alt 3D-3, the leading (strongest) coefficient

(corresponds to i = 0) out of 2L coefficients is reported per layer in a WB manner (as a WB report). The first group (K-l strongest coefficients per layer that use a larger bit allocation) is then determined directly from the reported WB amplitudes, without any explicit reporting, based on a fixed rule. A few examples of a fixed rule are as fol lows .

[0179] In one instance of Ex 3D-0, the reported WB amplitudes for the remaining

2L-1 coefficient are sorted in decreasing order, and the first K-l of the sorted amplitudes form the first group and the remaining sorted amplitudes form the second group. If the WB ampl itudes for two coefficients are identical , then the WB amp1 itudes are sorted in increasing order of coefficient index i, i.e., if are two WB

amplitudes for coefficient then are sorted as

and as otherwise.

[0180] In one instance of Ex 3D-1, the reported WB amplitudes for the remaining

2L-1 coefficient are sorted in decreasing order, and the first K-l of the sorted amplitudes form the first group and the remaining sorted amplitudes form the second group. If the WB ampl itudes for two coeff icients are ident ical , then the WB ampl i tudes are sorted in decreasing order of coefficient index /, i.e., if are two WB

amplitudes for coefficient then are sorted as

and as otherwise

[0181] The amplitude quantization in this case (K< 2L) is either dependent (i.e., differential as proposed in the aforementioned embodiments 0) or independent for each of the remaining 2L-1 coefficients. One of the two amplitude quantization methods may be used in the speci f icai ton.

[0182] In some embodiments 3E, for both wideband only and wideband + subband amplitude quantization (depending on RRC configuration, cf. the aforementioned embodiments 3B) , amplitude quantization is independent for each of the remaining 2L-1 coefficients and for each layer. The codebook for amplitude quantization is as foil ows .

[0183] In one example of WB amplitude codebook, which corresponds to

An example of WB amplitude codebook table is

shown in TABLE 1. Two alternatives are shown for indexing, one in increasing and the other in decreasing order of amplitudes, one of them may be fixed. [0184] In one example of SB amplitude codebook, for the first

group (for which which corresponds to for the

second group (for which SB amplitude is not reported). An example of SB

amplitude codebook table is shown in TABLE 2.

[0185] Two alternatives are shown for indexing, one in increasing and the other in decreasing order of amplitudes, one of them may be fixed In a variation, there is no separate codebook for SB amplitude. The SB amplitude codebook is corresponds to indices or 0,1 (Alt 1) in the WB amplitude codebook TABLE 1.

[0186] [Table 1]

[0187] [Table 2]

[0188] In some embodiments 3F, for both wideband only and wideband + subband amplitude quantization (depending on RRC configuration, cf. the aforementioned embodiments 3B) , amplitude quantization is independent for each of the remaining 27,-1 coefficients and for each layer. The codebook for amplitude quantization is as follows.

[0189] In one example of WB amplitude codebook, which corresponds to

An example of WB amplitude codebook table is shown

in TABLE 3. Two alternatives are shown for indexing, one in increasing and the other in decreasing order of amplitudes, one of them may be fixed.

[0190] In another example of SB ampl itude codebook, for

the first group (for which which corresponds to and

for the second group (for which SB amplitude is not reported).

An example of SB. amplitude codebook table is shown in TABLE 4. Two alternatives are shown for indexing, one in increasing and the other in decreasing order of amplitudes, one of them may fixed in a specif ication. In a variation, there is no separate codebook for SB amplitude. The SB amplitude codebook is corresponds to indices

0) or 0, 1 (Alt 1) in the WB amplitude codebook table TABLE 3.

[0191]

[0192]

[0193] In some embodiments 3G, the WB amplitude codebook is according to of Alt 0 and Alt 1 in TABLE 1 and the SB amplitude codebook is according to one Alt 0 and Alt 1 in TABLE 4. [0194] In some embodiments 3H, the WB amplitude codebook is according to one of Alt 0 and Alt 1 in TABLE 3 and the SB amplitude codebook is according to one of Alt 0 and Alt 1 in TABLE 2.

[0195] In some embodiments 31, the WB amplitude codebook is according to one of Alt 0 and Alt 1 in TABLE 1 and the SB amplitude codebook is according to one of Alt 0 and Alt 1 in TABLE 5.

[0196] [Table 5]

[0197] In some embodiments 3J , the WB amplitude codebook is according to one of Alt 0 and Alt 1 in TABLE 1 and the SB amplitude codebook is according to one of Alt 0 and Alt 1 in TABLE 6.

[0198] [Table 6]

[0199] In some embodiments 3K, the WB amplitude codebook is according to one of Alt 0 and Alt 1 in TABLE 1 and two SB amplitude codebooks are supported, {1,-JXi} and example, the two SB codebooks are {1, Vl.4125} and { and the corresponding SB codebook table is shown in TABLE 7. Another example is shown in TABLE 8. In both tables, two alternatives (Alt 0 and Alt 1) of index (TA.SB) of SB amplitude (p ₂ ,i,i) mapping is shown.

[0200] The reporting or configuration of SB Codebook Index (TSB CB) are according to at least one of the following alternatives. In one example of Alt 3K-0, one of the two SB codebooks is fixed in the specification., for example, {l,V0.7079). In another example of Alt 3K-1, one of the two SB codebooks is configured to the UE. For example this configuration can be via 1-bit RRC sign baling or more dynamic MAC CE based or DCI based signaling.

[0201] In yet another example of Alt 3K-2, the UE reports one of the two SB codebooks as part of the CSI report where this reporting is in a WB manner. Also, this reporting can either be joint with at least one of other WB CSI reports (for example WB PMI or RI) or separate as a new WB CSI report. The WB reporting of TSB CB is according to at least one of the following sub-alternatives.

[0202] In one instance of Alt 3K-2-0, ½ CB is reported layer-common and coefficient-common and a 1-bit WB CSI report is reported common for all layers and common for all coefficients (K-l), where K is defined as in the aforementioned embodiments 3B.

[0203] In another instance of Alt 3K-2-1, 7 _S B CB is reported layer-common and coef f icient-independent and a 1-bit WB CSI report is reported common for all layers and independently for all coefficients (K-l), where K is defined as in the aforementioned embodiments 3B. So, the total number of WB reporting bits is K-l.

[0204] In yet another instance of Alt 3K-2-2, YSB CB I S reported layer-independent and coeff icient-common and a 1-bit WB CSI report is reported independently for all layers and common for all coefficients (K-l), where K is defined as in the aforementioned embodiments 3B. So, the total number of WB reporting bits is R, where R is the number of layers, (1 and 2 for rank 1 and rank 2, respectively). [0205] In yet another instance of Alt 3K-2-3, /SBCB is reported layer- independent and coefficient-independent and a 1-bit WB CSI report is reported independently for all layers and independently for all coefficients (K-l) , where K is defined as in the aforementioned embodiments 3B. So, the total number of WB reporting bits is R(K-l) , where R is the number of layers, and hence for rankl and rank 2, the number of bits is respectively.

[0206]

[0208] The WB and SB amplitude quantization codebooks according to only one of the aforementioned embodiments 3E, 3F, 3G, 3H, 31, 3J, and 3K will be specified in the present disclosure.

[0209] In some embodiments 3L, for 4 antenna ports (e.g. {3000, 3001, 3002,

3003}), 8 antenna ports 12 antenna ports (e.g. {3000, 3001, ···, 3011}), 16 antenna ports (e.g. {3000, 3001, ···, 3015}), 24 antenna ports (e.g. {13000, 3001, ···, 3023}), and 32 antenna ports (e.g. {3000, 3001, ···, 3031}), when the UE is configured with higher layer parameters CodebookType set to Type2_Parameters, where Type2__Parameters contains parameters {CodebookConfig-Nl, CodebookConfig-N2, NumberOfBeams, PhaseAlphabetSize, SubbandAmplitude} .

[0210] In such embodiments, the values of N, and N ₂ are configured with the higher- layer parameters CodebookConfig-Nl and CodebookConfig-N2, respectively. The number of CSI-RS ports, In such embodiments, the value of L is

configured with the higher-layer parameter NumberOfBeams, where L = 2 when

and In suc ^h embodiments, the value of N _PSK is configured

with the higher-layer parameter PhaseAlphabetSize, where with

indicates QPSK phase codebook and N _PSK = 8 indicates 8PSK phase codebook. In such embodiments, the UE is configured with the higher- layer parameter SubbandAmplitude set to OFF or 0Ν.

[0211] When υ≤2 , where _υ is the associated RI value, each PMI value corresponds to the codebook indices i ₁ and i ₂ where

[0212] The L vectors combined by the codebook are identified by the indices

[0213] The strongest coefficient on layer is identified by

The amplitude coefficient indicators are

[0214] The indicators respectively indicate the WB and SB

components of the coefficient amplitudes as explained earlier in the disclosure. The mapping from to the WB amplitude coefficient is given in TABLE 9 and the mapping from to the SB amplitude coefficient is given in TABLE 10.

[0215] The ampl itude coefficients are represented by

for respectively one-to-one map to

used earlier (or later) in the disclosure for the WB and SB amplitude components.

[0216] [Table 9]

[0217] [Table 10]

[0218] The phase coefficient indicators are for

The amplitude and phase coefficient indicators are reported as follows. In one example, the indicators and

are not reported for

[0219] In another example, the remaining elements of are

reported, where be the number of elements of that satisfy

[0220] In yet another example, the remaining elements of

are reported as follows. In one instance, when SubbandAmpl itude - OFF:

for and is not reported for and for

the elements of corresponding to the coefficients that satisfy

as determined by the reported elements of are reported, where

and the remaining elements of are not reported and are

set to

[0221] In another instance, when SubbandAmpl i tude = the

elements of corresponding to the strongest coefficients,

as determined by the corresponding elements of are reported, where and

The values of are given in TABLE 11. The remaining

elements of are not reported and are set to The elements

of corresponding to the remaining coeff icients sat isfying

are reported, where The remaining elements of are not

reported and are set to and when two elements, of the reported

are identical , then the element min(x,y) is prioritized to be included

in the set of the strongest coefficients for

reporting. In another alternative, is prioritized to be included in the set

of the strongest coefficients for reporting. [0222] [Table 11]

[0223] The phase coefficient is determined by the quantity

[0224] In some embodiments 3M, for 4 antenna ports (e.g. {3000, 3001, 3002,

3003}), 8 antenna ports 12 antenna ports (e.g. {3000,

3001, ···, 3011}), 16 antenna ports (e.g. {3000, 3001, ···, 3015}), 24 antenna ports (e.g. {13000, 3001, ···, 3023}), and 32 antenna ports (e.g. {3000, 3001, ···, 3031}), when the UE is configured with higher layer parameters CodebookType set to Type2_Parameters, where Type2_Parameters contains parameters {CodebookConfig-Nl, CodebookConfig-N2, NumberOfBeams, PhaseAlphabetSize, SubbandAmplitude, PortSelectionSamplingSize} .

[0225] In such embodiments, the number of CSI-RS ports is given by such embodiments, the value of L is configured with the

higher-layer parameter NumberOfBeams, where L = 2 when when

embodiments, the value of d is configured with the higher layer

parameter PortSelectionSamplingSize, where and d≤ L

lternatively In such embodiments, the value of N _PSK is configured with the higher-layer parameter PhaseAlphabetSize, where

indicates QPS phase codebook and indicates 8PSK phase codebook. In such

embodiments, the UE is configured with the higher-layer parameter SubbandAmplitude set to OFF or ON.

[0226] When where υ is the associated RI value, each PMI value

corresponds to the codebook indices where

[0227] The L antenna ports per polarization are selected by the index where

The rest of the details are the same as in the aforementioned

embodiments (e.g., embodiment 3D.

[0228] In some embodiments 4, for Alt 1-0 or Alt 1-1 of amplitude sorting, the bit al location is common for each of L beams across two polarizations: for L - 2 beams and max 2 bits/amplitude, the bit al location is according to at least one alternative in TABLE 12; for L = 2 beams and max 3 bits/amplitude, the bit allocation is according to at least one alternative in TALE 13; for L = 3 beams and max 2 bits/amplitude, the bit allocation is according to at least one alternative in TABLE 14; for L = 3 beams and max 3 bits/amplitude, the bit allocation is according to at least one alternative in TABEL 15; for L = 4 beams and max 2 bits/amplitude, the bit allocation is according to at least one alternative in TABLE 16; and for L = 4 beams and max 3 bits/ampl itude, the bit al locat ion is according to at least one alternat ive in TABLE 17. [0229] Note that if the number of bit then the amplitude is equal to

1 (strongest beam) and if then the amplitude codebook is as in the

aforementioned embodiment 0. In these alternatives, the strongest beam is common for both of the two polarizations hence the corresponding amplitudes are

not reported (assumed to be 1).

[0230] The UE is configured with an L value belonging to {2, 3, 4} and a max number of bits/ampl itude value belonging to {2, 3}. This configuration is via higher layer RRC signalling. In another alternative, the UE reports a preferred lvalue (WB report) and a max number of bits/amplitude value belonging to {2, 3} is configured via RRC signaling.

[0231] In one embodiment, only one of the alternatives in TABLES 12-17 is supported in the present disclosure. In another embodiment , the UE is configured with one of the bit allocation alternatives in TABLES 12-17 via higher layer RRC or more dynamic MAC CE based or DCI based signal 1 ing. In yet another embodiment, the UE reports a preferred bit allocation as part of the CSI report where this reporting is WB either jointly with at least one of other WB CSI reports or separately as another WB CSI report .

[0232]

[0238] In some embodiments 5, for Alt 1-0 or Alt 1-1 of amplitude sorting, the bi t al locat ion is common for each of L beams across two polar izat ions : for L = 2 beams and max 2 bits/ampl itude, the bit al locat ion is according to at least one alternat ive in TABLE 18; for L - 2 beams and max 3 bits/amplitude, the bit al location is according to at least one alternative in TABLE 19; for L- 3 beams and max 2 bits/amplitude, the bit allocation is according to at least one alternative in TABLE 20; for L = 3 beams and max 3 bits/amplitude, the bit allocation is according to at least one alternative in TABLE 21; for L = 4 beams and max 2 bits/ampl itude, the bit allocation is according to at least one alternative in TABLE 22; and for L = 4 beams and max 3 bits/ampl i tude, the bi t al locat ion is according to at least one alternat ive in TABLE 23.

[0239] Note that if the number of bit then the amplitude is equal to

1 and if then the amplitude codebook is as in the aforementioned embodiment

0. In these alternatives, the strongest beam corresponds to one of the two polarizations hence the corresponding amplitude is not reported (assumed

to be 1) , and the amplitude corresponding to the other polarization is reported.

[0240] The UE is configured with an L value belonging to {2, 3, 4} and a max number of bits/amplitude value belonging to {2, 3}. This configuration is via higher layer RRC signalling. In another alternative, the UE reports a preferred lvalue (WB report) and a max number of bits/amplitude value belonging to {2, 3} is configured via RRC signaling.

[0241] In one embodiment, only one of the alternatives in TABLES 18-23 is supported in the specification. In another method, the UE is configured with one of the bit allocation alternatives in TABLES 18-23 via higher layer RRC or more dynamic MAC CE based or DCI based signalling. In yet another alternative, the UE reports a preferred bit allocation as part of the CSI report where this reporting is WB either jointly with at least one of other WB CSI reports or separately as another WB CSI report .

[0242]

[0248] In some embodiments 6, for Alt 1-2 or Alt 1-3 of amplitude sorting, the bit allocation is independent for each of L beams and two polarizations: for L = 2 beams and max 2 bits/amplitude, the bit allocation is according to at least one alternative in TABLE 24; for L = 2 beams and max 3 bits/ampl itude, the bit allocation is according to at least one alternative in TABLE 25; for L = 3 beams and max 2 bits/amplitude, the bit allocation is according to at least one alternat ive in TABLE 26; for L - 3 beams and max 3 bits/amplitude, the bit allocation is according to at least one alternative in TABLE 27; for L - 4 beams and max 2 bits/amplitude, the bit allocation is according to at least one alternative in TABLE 28; and for L = 4 beams and max 3 bits/amplitude, the bit allocation is according to at least one alternative in TABLE 29.

[0249] Note that if the number of bit then the amplitude is equal to

1 and if then the amplitude codebook is as in the aforementioned embodiments

0. In these alternatives, the strongest beam corresponds to one of the two polarizations (/ = 0), hence the corresponding amplitude is not reported (assumed to be 1) , and the ampl i tude corresponding to the other polar izat ion (/ = /,) is reported. The amplitudes for remaining 2L-2 coefficients are reported independently.

[0250] The UE is configured with an L value belonging to {2, 3, 4} and a max number of bits/ampl itude value belonging to {2, 3}. This configuration is via higher layer RRC signalling. In another alternative, the UE reports a preferred lvalue (WB report) and a max number of bits/amplitude value belonging to {2, 3} is configured via RRC signaling.

[0251] In one embodiment, only one of the alternatives in TABLES 24-29 is supported in the specification. In another embodiment, the UE is configured with one of the bit al location alternatives in TABLE 24-29 via higher layer RRC or more dynamic MAC CE based or DCI based signalling. In yet another alternative, the UE reports a preferred bit allocation as part of the CSI report where this reporting is WB either jointly with at least one of other WB CSI reports or separately as another WB CSI report .

[0258] In some embodiments 7, the bit-allocation for phase is according to at least one of the following. In one example of Alt 7-0, the bit-allocation for phase i s the same as that for ampl itude and is according to at least one of the bi t al locat ion alternatives in the aforementioned embodiments 4 - 6. In another example of Alt 7-1, the bit-allocation for phase is different from that for amplitude and is according to at least one of the bit allocation alternatives in the aforementioned embodiments 4 - 6. In yet another example of Alt 7-2, the bit allocation of phase is fixed, for example to equal bit allocation to 2 or 3 bits.

[0259] In some embodiments 8, a UE is configured (via RRC signalling) with an

L value belonging to {2, 3, 4}, a max number of bits/ampl itude value belonging to {2, 3}, and the total of ampl itude quant izat ion bi ts The

UE reports the quantized amplitudes according to one of the bit allocation alternatives in the aforementioned embodiments 4 - 6. If there are more than one bit allocation alternatives that satisfy the configured value of the total of amplitude quantization bits, then the UE reports a preferred bit allocation out of all such bit allocation alternatives where this reporting is WB either jointly with other WB CSI reports or separately as another WB CSI report.

[0260] In some embodiments 9, a UE is configured with bit allocation for amplitude or/and phase reporting according to at least one of the following alternatives. In one instance of Alt 9-0, the bit allocation is equal for all L. In one instance of Alt 9-1, the bi t al locat ion is unequal for all lvalues . In one instance of Alt 9-2, the bit allocation is equal or unequal for all L values depending on configuration. In one instance of Alt 9-3, the bit allocation is equal for L < M and is unequal for L > M. An example value for M is 2. Another example value for M is 3.

[0261] FIGURE 13 illustrates a flowchart of a method 1300 for PMI reporting according to embodiments of the present disclosure. The method 1300 may be performed by a UE, for example, UE 116, according to embodiments of the present disclosure. The embodiment of the method 1300 illustrated in FIGURE 13 is for illustration only. FIGURE 13 does not limit the scope of this disclosure to any par t icular implementation.

[0262] The method 1300 begins with the UE generating a report for a PMI (step

1305). In step 1305, the report includes, at least, (i) a wideband amplitude coefficient indicator that is common for a plurality of subbands configured for reporting and (ii) a subband amplitude coefficient indicator and a subband phase coefficient indicator for each of the subbands. In some embodiments, the report includes 2*L number of beam coefficients for each of the subbands and for each of a plurality of υ layers where L is a number of beams configured for reporting and υ is a RI value associated with the reported PMI. Each of one or more of the beam coefficients includes (i) the wideband ampl i tude coeff icient indicator that is common for the subbands and (ii) the subband ampl itudecoef f icient indicator and the subband phase coefficient indicator for each of the subbands. Additionally, at least one of the beam coefficients is reported using a number of bits that is unequal to number of bits used to report another of the beam coefficients.

[0263] In various embodiments, the UE includes in the report, for each of the υ layers, a strongest of the 2*L number of beam coefficients that is common for the subbands and groups the remaining number of beam coefficients into two groups.

In these embodiments, a fewer number of bits are used to report the beam coefficients in a second of the two groups; hence, an unequal number of bits to report the two groups. In at least some of these embodiments, a first of the two groups includes beam coefficients that are strongest coefficients of the remaining 2*L-1

number of beam coefficients and the second group includes 2L -min(M,K) beam coefficients where f is a number of beam coefficients whose wideband amplitude coefficient indicators indicate non-zero wideband ampl itude values and K i s a posit ive integer. In these embodiments, the report does not include subband amplitude coefficient indicators for the second group of beam coef f icients. In some embodiments, the strongest coefficients used to group the remaining 2*L-l beam coefficients into the two groups are determined based on the wideband amplitude coefficient indicator for each of the beam coefficients.

[0264] In various embodiments, for each beam coefficient in the first group,

3 bits are used to report the wideband amplitude coefficient indicator; 1 bit is used to report the subband amplitude coefficient indicator; and 2 or 3 bits are configured to report the subband phase coefficient indicator. For the second group, for each beam coefficient, 3 bits are used to report the wideband amplitude coefficient indicator; for each beam coefficient in the Μ-παη(Μ,Κ) beam coefficients whose wideband amplitude coefficient indicators indicate non-zero wideband amplitude values, 2 bits are used to report the subband phase coefficient indicator; and for the remaining 2L - M beam coefficients whose wideband amplitude coefficient indicators indicate a zero wideband amplitude value, subband phase coefficient indicators are not reported.

[0265] Thereafter, the UE transmits the generated report for the PMI to a BS

(step 1310). In step 1310, the UE reports the PMI to the BS, for example, BS 102.

[0266] 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.

[0267] 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 only by the claims. Moreover, none of the claims are intended to invoke 35 U.S.C. § 112(f) unless the exact words "means for" are followed by a participle.