Apparatus and method for per-channel state information reference signal power delay profile estimation

Abstract

According to one aspect of the present disclosure, a method of wireless communication of a user equipment (UE) is provided. The method may include identifying, by at least one processor, a channel state information (CSI)-reference signal (RS) (CSI-RS) resource for channel estimation. The method may include performing, by the at least one processor, a per-CSI-RS resource power delay profile (PDP) estimation. The method may include performing, by the at least one processor, a channel estimation procedure based on the per-CSI-RS resource PDP estimation.

Description

APPARATUS AND METHOD FOR PER-CHANNEL STATE INFORMATION REFERENCE SIGNAL POWER DELAY PROFILE ESTIMATIONBACKGROUND

[0001] Embodiments of the present disclosure relate to apparatus and method for wireless communication.

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. In cellular communication, such as the 4th-gen eration (4G) Long Term Evolution (LTE) and the 5th- generation (5G) New Radio (NR), the 3rd Generation Partnership Project (3GPP) defines various procedures for channel estimation.SUMMARY

[0003] According to one aspect of the present disclosure, a method of wireless communication of a user equipment (UE) is provided. The method may include identifying, by at least one processor, a channel state information (CSI)-reference signal (RS) (CSLRS) resource for channel estimation. The method may include performing, by the at least one processor, a per-CSL RS resource power delay profile (PDP) estimation. The method may include performing, by the at least one processor, a channel estimation procedure based on the per-CSLRS resource PDP estimation.

[0004] According to another aspect of the present disclosure, an apparatus for wireless communication of a UE is provided. The apparatus may include at least one processor. The apparatus may include memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying a CSLRS resource for channel estimation. The apparatus may include memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform performing a per- CSLRS resource PDP estimation. The apparatus may include memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform performing a channel estimation procedure based on the per-CSLRS resource PDP estimation.

[0005] According to a further aspect of the present disclosure, a non-transitory computer- readable medium storing instructions for a UE is provided. The instructions, which when executedAtty. Dkt. No. 10073-01-0171-PCTby at least one processor of the UE, cause the at least one processor to perform identifying a CSI- RS resource for channel estimation. The instructions, which when executed by at least one processor of the UE, cause the at least one processor to perform performing a per-CSI-RS resource PDP estimation. The instructions, which when executed by at least one processor of the UE, cause the at least one processor to perform performing a channel estimation procedure based on the per- CSI-RS resource PDP estimation.

[0006] These illustrative embodiments are mentioned not to limit or define the present disclosure, but to provide examples to aid understanding thereof. Additional embodiments are discussed in the Detailed Description, and further description is provided there.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable a person skilled in the pertinent art to make and use the present disclosure.

[0008] FIG. 1 illustrates an exemplary wireless network, according to some embodiments of the present disclosure.

[0009] FIG. 2 illustrates a block diagram of an exemplary node, according to some embodiments of the present disclosure.

[0010] FIG. 3 illustrates a detailed block diagram of an exemplary apparatus that includes a baseband chip, a radio frequency (RF) chip, and a host chip, according to some embodiments of the present disclosure.

[0011] FIG. 4 illustrates a physical resource block (PRB) that carries a 32-port CSI-RS resource, according to certain aspects of the present disclosure.

[0012] FIG. 5 illustrates a graphical representation of a mean squared error (MSE) versus signal -to-noise ratio (SNR) plot of channel estimation performance achieved using an exemplary per-CSI-RS PDP estimation technique, according to some aspects of the present disclosure.

[0013] FIG. 6 is a flowchart of an exemplary method of wireless communication, according to some aspects of the present disclosure.

[0014] Embodiments of the present disclosure will be described with reference to the accompanying drawings.Atty. Dkt. No. 10073-01-0171-PCTDETAILED DESCRIPTION

[0015] Although specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the pertinent art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the present disclosure. It will be apparent to a person skilled in the pertinent art that the present disclosure can also be employed in a variety of other applications.

[0016] It is noted that references in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” “some embodiments,” “certain embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it would be within the knowledge of a person skilled in the pertinent art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0017] In general, terminology may be understood at least in part from usage in context. For example, the term “one or more” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a,” “an,” or “the,” again, may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

[0018] Various aspects of wireless communication systems will now be described with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, units, components, circuits, steps, operations, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, firmware, computer software, or any combination thereof. Whether such elements are implemented as hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system.Atty. Dkt. No. 10073-01-0171-PCT

[0019] The techniques described herein may be used for various wireless communication networks, such as code division multiple access (CDMA) system, time division multiple access (TDMA) system, frequency division multiple access (FDMA) system, orthogonal frequency division multiple access (OFDMA) system, single-carrier frequency division multiple access (SC- FDMA) system, wireless local area network (WLAN) system, and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio access technology (RAT), such as Universal Terrestrial Radio Access (UTRA), evolved UTRA (E-UTRA), CDMA 1000, etc. A TDMA network may implement a RAT, such as the Global System for Mobile Communications (GSM). An OFDMA network may implement a RAT, such as LTE or NR. A WLAN system may implement a RAT, such as Wi-Fi. The techniques described herein may be used for the wireless networks and RATs mentioned above, as well as other wireless networks and RATs.

[0020] A power delay profile (PDP) represents the intensity of a signal received through a multipath channel as a function of time delay. The time delay is the difference in travel time between multipath arrivals. A signal’s PDP may be measured empirically and used to extract certain channel parameters, e.g., such as the delay spread. The PDP may be estimated by taking the spatial average of a channel’s baseband impulse response over a local area.

[0021] In wireless systems, such as 5G NR, PDP is a key factor in achieving a channel estimation with a high-degree of accuracy. In systems in which channel estimation is performed using a CSI-RS resource that includes a plurality of two-port CDM groups, PDP estimation is conducted per-CDM group and applied to the channel estimation for the corresponding CDM group, respectively. In a 32-port CSLRS resource with sixteen 2-port frequency-domain (FD)- CDM groups, the UE performs PDP estimation sixteen times, one for each of the 2-port FD-CDM groups in the 32-port CSLRS resource. These computations require a large number of clock cycles and consume an undesirable amount of power.

[0022] Thus, there exists an unmet need for a PDP estimation technique that may be applied to channel estimation using a reduced number of clock cycles and less power, while at the same time achieving a high-degree of accuracy in channel estimation.

[0023] To overcome these and other challenges, the present disclosure provides an exemplary per-CSLRS PDP estimation technique that uses fewer clock cycles and less power, as compared to per-CDM group PDP estimation technique of other systems. For example, a UE with 5G NR capabilities may assume that a CSI-RS resource configured for channel qualityAtty. Dkt. No. 10073-01-0171-PCTmeasurement is resource-wise quasi -located. To reduce the complexity of PDP estimation, the present disclosure provides a per-CSI-RS resource PDP estimation to limit the number of PDP computations performed for channel estimation. Additional details of the exemplary per-CSI-RS resource PDP estimation technique are provided below in connection with FIGs. 1-6.

[0024] FIG. 1 illustrates an exemplary wireless network 100, in which some aspects of the present disclosure may be implemented, according to some embodiments of the present disclosure. As shown in FIG. 1, wireless network 100 may include a network of nodes, such as user equipment 102, an access node 104, and a core network element 106. User equipment 102 may be any terminal device, such as a mobile phone, a desktop computer, a laptop computer, a tablet, a vehicle computer, a gaming console, a printer, a positioning device, a wearable electronic device, a smart sensor, or any other device capable of receiving, processing, and transmitting information, such as any member of a vehicle to everything (V2X) network, a cluster network, a smart grid node, or an Internet-of-Things (loT) node. It is understood that user equipment 102 is illustrated as a mobile phone simply by way of illustration and not by way of limitation.

[0025] Access node 104 may be a device that communicates with user equipment 102, such as a wireless access point, a base station (BS), a Node B, an enhanced Node B (eNodeB or eNB), a next-generation NodeB (gNodeB or gNB), a cluster master node, or the like. Access node 104 may have a wired connection to user equipment 102, a wireless connection to user equipment 102, or any combination thereof. Access node 104 may be connected to user equipment 102 by multiple connections, and user equipment 102 may be connected to other access nodes in addition to access node 104. Access node 104 may also be connected to other user equipments. When configured as a gNB, access node 104 may operate in millimeter wave (mmW) frequencies and / or near mmW frequencies in communication with the user equipment 102. When access node 104 operates in mmW or near mmW frequencies, the access node 104 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the radio frequency (RF) in the electromagnetic spectrum. EHF has a range of 30 GHz to 200 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW or near mmW radio frequency band have extremely high path loss and a short range. The mmW base station may utilize beamforming with user equipment 102 to compensate for the extremely high path loss and short range. It is understood that access nodeAtty. Dkt. No. 10073-01-0171-PCT104 is illustrated by a radio tower by way of illustration and not by way of limitation.

[0026] Access nodes 104, which are collectively referred to as E-UTRAN in the evolved packet core network (EPC) and as NG-RAN in the 5G core network (5GC), interface with the EPC and 5GC, respectively, through dedicated backhaul links (e.g., SI interface). In addition to other functions, access node 104 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. Access nodes 104 may communicate directly or indirectly (e.g., through the 5GC) with each other over backhaul links (e.g., X2 interface). The backhaul links may be wired or wireless.

[0027] Core network element 106 may serve access node 104 and user equipment 102 to provide core network services. Examples of core network element 106 may include a home subscriber server (HSS), a mobility management entity (MME), a serving gateway (SGW), or a packet data network gateway (PGW). These are examples of core network elements of an evolved packet core (EPC) system, which is a core network for the LTE system. Other core network elements may be used in LTE and in other communication systems. In some embodiments, core network element 106 includes an access and mobility management function (AMF), a session management function (SMF), or a user plane function (UPF) of the 5GC for the NR system. The AMF may be in communication with a Unified Data Management (UDM). The AMF is the control node that processes the signaling between the user equipment 102 and the 5GC. Generally, the AMF provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF. The UPF provides user equipment (UE) IP address allocation as well as other functions. The UPF is connected to the IP Services. The IP Services may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and / or other IP services. It is understood that core network element 106 is shown as a set of rack-mounted servers by way of illustration and not by way of limitation.

[0028] Core network element 106 may connect with a large network, such as the Internet 108, or another Internet Protocol (IP) network, to communicate packet data over any distance. In this way, data from user equipment 102 may be communicated to other user equipments connectedAtty. Dkt. No. 10073-01-0171-PCTto other access points, including, for example, a computer 110 connected to Internet 108, for example, using a wired connection or a wireless connection, or to a tablet 112 wirelessly connected to Internet 108 via a router 114. Thus, computer 110 and tablet 112 provide additional examples of possible user equipments, and router 114 provides an example of another possible access node.

[0029] A generic example of a rack-mounted server is provided as an illustration of core network element 106. However, there may be multiple elements in the core network including database servers, such as a database 116, and security and authentication servers, such as an authentication server 118. Database 116 may, for example, manage data related to user subscription to network services. A home location register (HLR) is an example of a standardized database of subscriber information for a cellular network. Likewise, authentication server 118 may handle authentication of users, sessions, and so on. In the NR system, an authentication server function (AUSF) device may be the entity to perform user equipment authentication. In some embodiments, a single server rack may handle multiple such functions, such that the connections between core network element 106, authentication server 118, and database 116, may be local connections within a single rack.

[0030] Each element in FIG. 1 may be considered a node of wireless network 100. More detail regarding the possible implementation of a node is provided by way of an example in the description of a node 200 in FIG. 2. Node 200 may be configured as user equipment 102, access node 104, or core network element 106 in FIG. 1. Similarly, node 200 may also be configured as computer 110, router 114, tablet 112, database 116, or authentication server 118 in FIG. 1. As shown in FIG. 2, node 200 may include a processor 202, a memory 204, and a transceiver 206. These components are shown as connected to one another by a bus, but other connection types are also permitted. When node 200 is user equipment 102, additional components may also be included, such as a user interface (UI), sensors, and the like. Similarly, node 200 may be implemented as a blade in a server system when node 200 is configured as core network element 106. Other implementations are also possible.

[0031] Transceiver 206 may include any suitable device for sending and / or receiving data. Node 200 may include one or more transceivers, although only one transceiver 206 is shown for simplicity of illustration. An antenna 208 is shown as a possible communication mechanism for node 200. Multiple antennas and / or arrays of antennas may be utilized for receiving multiple spatially multiplex data streams. Additionally, examples of node 200 may communicate using wired techniques rather than (or in addition to) wireless techniques. For example, access node 104Atty. Dkt. No. 10073-01-0171-PCTmay communicate wirelessly to user equipment 102 and may communicate by a wired connection (for example, by optical or coaxial cable) to core network element 106. Other communication hardware, such as a network interface card (NIC), may be included as well.

[0032] As shown in FIG. 2, node 200 may include processor 202. Although only one processor is shown, it is understood that multiple processors can be included. Processor 202 may include microprocessors, microcontroller units (MCUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout the present disclosure. Processor 202 may be a hardware device having one or more processing cores. Processor 202 may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software can include computer instructions written in an interpreted language, a compiled language, or machine code. Other techniques for instructing hardware are also permitted under the broad category of software.

[0033] As shown in FIG. 2, node 200 may also include memory 204. Although only one memory is shown, it is understood that multiple memories can be included. Memory 204 can broadly include both memory and storage. For example, memory 204 may include random-access memory (RAM), read-only memory (ROM), static RAM (SRAM), dynamic RAM (DRAM), ferroelectric RAM (FRAM), electrically erasable programmable ROM (EEPROM), compact disc readonly memory (CD-ROM) or other optical disk storage, hard disk drive (HDD), such as magnetic disk storage or other magnetic storage devices, Flash drive, solid-state drive (SSD), or any other medium that can be used to carry or store desired program code in the form of instructions that can be accessed and executed by processor 202. Broadly, memory 204 may be embodied by any computer-readable medium, such as a non-transitory computer-readable medium.

[0034] Processor 202, memory 204, and transceiver 206 may be implemented in various forms in node 200 for performing wireless communication functions. In some embodiments, at least two of processor 202, memory 204, and transceiver 206 are integrated into a single system- on-chip (SoC) or a single system-in-package (SiP). In some embodiments, processor 202, memory 204, and transceiver 206 of node 200 are implemented (e.g., integrated) on one or more SoCs. InAtty. Dkt. No. 10073-01-0171-PCTone example, processor 202 and memory 204 may be integrated on an application processor (AP) SoC (sometimes known as a “host,” referred to herein as a “host chip”) that handles application processing in an operating system (OS) environment, including generating raw data to be transmitted. In another example, processor 202 and memory 204 may be integrated on a baseband processor (BP) SoC (sometimes known as a “modem,” referred to herein as a “baseband chip”) that converts the raw data, e.g., from the host chip, to signals that can be used to modulate the carrier frequency for transmission, and vice versa, which can run a real-time operating system (RTOS). In still another example, processor 202 and transceiver 206 (and memory 204 in some cases) may be integrated on an RF SoC (sometimes known as a “transceiver,” referred to herein as an “RF chip”) that transmits and receives RF signals with antenna 208. It is understood that in some examples, some or all of the host chip, baseband chip, and RF chip may be integrated as a single SoC. For example, a baseband chip and an RF chip may be integrated into a single SoC that manages all the radio functions for cellular communication.

[0035] Referring back to FIG. 1, in some embodiments, user equipment 102 may perform an exemplary per-CSI-RS PDP estimation technique that uses fewer clock cycles and less power, as compared to per-CDM group PDP estimation, for channel estimation using a CSI-RS resource with a plurality of 2-port CDM groups. Additional details of the exemplary per-CSI-RS resource PDP estimation technique are provided below in connection with FIGs. 3-6.

[0036] FIG. 3 illustrates a block diagram of an exemplary apparatus 300 including a baseband chip 302, an RF chip 304, and a host chip 306, according to some embodiments of the present disclosure. FIG. 4 illustrates a PRB 400 that carries a 32-port CSI-RS resource, according to certain aspects of the present disclosure. FIGs. 3 and 4 will be described together.

[0037] Referring to FIG. 3, apparatus 300 may be implemented as user equipment 102 of wireless network 100 in FIG. 1. As shown in FIG. 3, apparatus 300 may include baseband chip 302, RF chip 304, host chip 306, and one or more antennas 310. In some embodiments, baseband chip 302 is implemented by a processor and a memory, and RF chip 304 is implemented by a processor, a memory, and a transceiver. Besides the on-chip memory 318 (also known as “internal memory,” e.g., registers, buffers, or caches) on each chip 302, 304, or 306, apparatus 300 may further include an external memory 308 (e.g., the system memory or main memory) that can be shared by each chip 302, 304, or 306 through the system / main bus. Although baseband chip 302 is illustrated as a standalone SoC in FIG. 3, it is understood that in one example, baseband chip 302 and RF chip 304 may be integrated as one SoC or one SiP; in another example, baseband chipAtty. Dkt. No. 10073-01-0171-PCT302 and host chip 306 may be integrated as one SoC or one SiP; in still another example, baseband chip 302, RF chip 304, and host chip 306 may be integrated as one SoC or one SiP, as described above.

[0038] In the uplink, host chip 306 may generate raw data and send it to baseband chip 302 for encoding, modulation, and mapping. Interface 314 of baseband chip 302 may receive the data from host chip 306. Baseband chip 302 may also access the raw data generated by host chip 306 and stored in external memory 308, for example, using the direct memory access (DMA). Baseband chip 302 may first encode (e.g., by source coding and / or channel coding) the raw data and modulate the coded data using any suitable modulation techniques, such as multi-phase shift keying (MPSK) modulation or quadrature amplitude modulation (QAM). Baseband chip 302 may perform any other functions, such as symbol or layer mapping, to convert the raw data into a signal that can be used to modulate the carrier frequency for transmission. In the uplink, baseband chip 302 may send the modulated signal to RF chip 304 via interface 314. RF chip 304, through the transmitter, may convert the modulated signal in the digital form into analog signals, i.e., RF signals, and perform any suitable front-end RF functions, such as filtering, digital pre-distortion, up-conversion, or sample-rate conversion. Antenna 310 (e.g., an antenna array) may transmit the RF signals provided by the transmitter of RF chip 304.

[0039] In the downlink, antenna 310 may receive RF signals from an access node or other wireless device. The RF signals may be passed to the receiver (Rx) of RF chip 304. RF chip 304 may perform any suitable front-end RF functions, such as filtering, IQ imbalance compensation, down-paging conversion, or sample-rate conversion, and convert the RF signals (e.g., transmission) into low-frequency digital signals (baseband signals) that can be processed by baseband chip 302.

[0040] Still referring to FIG. 3, baseband chip 302 may include a CSI-RS resource identification component 320, a PDP estimation component 322, and a channel estimation component 324. CSI-RS resource identification component 320 may be configured to identify the CSI-RS resource for use in channel estimation based on signaling received from a base station. FIG. 4 illustrates a PRB 400 may carry a CSI-RS resource, which includes a plurality of 2-port CDM groups 402. In the present example, a 32-port FD-CDM2 CSI-RS resource is illustrated, which includes sixteen pairs of 2-port CDM groups 402, each depicted with a different shading.

[0041] Rather than performing PDP estimation for each pair of the 2-port CDM groups, PDP estimation component 322 may select one of the sixteen pairs of 2-port CDM groups 402 forAtty. Dkt. No. 10073-01-0171-PCTPDP estimation. Then, PDP estimation component 322 may perform PDP estimation on the selected 2-port CDM group 402. This PDP estimation may be applied to each pair of the 2-port CDM groups 402. This may be referred to as a “per-CSI-RS resource PDP estimation.” In some embodiments, PDP estimation component 322 may perform PDP estimation on the first 2-port CDM group 402. Using the single PDP estimation, channel estimation component 324 may perform channel estimation by applying the PDP estimation to all of the 2-port CDM groups 402 in the CSI-RS resource.

[0042] FIG. 5 illustrates a graphical representation 500 of an MSE and SNR for channel estimation performance achieved using the exemplary per-CSI-RS PDP estimation technique, according to some aspects of the present disclosure.

[0043] From the clock-cycle perspective, given a 32-port FD-CDM2 CSI-RS resource, the PDP estimation for one of the 2-port FD-CDM groups uses N cycles to complete the computation. The conventional per-CDM group PDP estimation technique performed for Using a 32-port FD- CDM2 CSI-RS resource would requirel6*N cycles. Thus, the exemplary per-CSI RS PDP estimation technique provides a 90% reduction in clock cycles to complete the computation. In terms of channel estimation performance, graphical representation 500 illustrates that the exemplary per-CSI-RS PDP estimation achieves nearly the same channel estimation performance (in terms of MSE vs. SNR) as that of the computationally intensive conventional per-CDM group PDP estimation.

[0044] Thus, the present disclosure provides an exemplary per-CSI-RS PDP estimation technique that uses fewer clock cycles and less power, as compared to per-CDM group PDP estimation, while maintaining a high-degree of channel estimation accuracy.

[0045] FIG. 6 is a flowchart of an exemplary method 600 (referred to hereinafter as “method 600”) of wireless communication, according to some aspects of the present disclosure. Method 600 may be performed by an apparatus, e.g., such as user equipment 102, node 200, apparatus 300, baseband chip 302, CSI-RS resource identification component 320, PDP estimation component 322, and / or channel estimation component 324, just to name a few. Method 600 may include steps 602-606, as described below. It is to be appreciated that some of the steps may be optional, and some of the steps may be performed simultaneously, or in a different order than shown in FIG. 6.

[0046] Referring to FIG. 6, at 602, the apparatus may identify a CSI-RS resource for channel estimation. For example, referring to FIG. 3, CSI-RS resource identification componentAtty. Dkt. No. 10073-01-0171-PCT320 may be configured to identify the CSI-RS for use in channel estimation based on signaling received from a base station. As shown in FIG. 4, PRB 400 may carry a CSI-RS resource that includes a plurality of 2-port CDM groups 402. In the present example, a 32-port FD-CDM2 CSI- RS resource is illustrated, which includes sixteen 2-port CDM groups 402, each depicted with a different shading.

[0047] At 604, the apparatus may perform a per-CSI-RS resource PDP estimation. For example, referring to FIG. 3, PDP estimation component 322 may perform PDP estimation on the selected 2-port CDM group 402. This PDP estimation may be applied to each pair of the 2-port CDM groups 402. This is referred to as a per-CSI-RS resource PDP estimation. Using the example CSI-RS resource illustrated in FIG. 4, taking a 32-port FD-CDM2 CSI-RS resource as an example, the UE conducts the PDP estimation based on any of the 2-port FD-CDM groups. One option is that PDP estimation component 322 conducts PDP estimation on the first 2-port CDM group 402. In some embodiments, the per-CSI-RS resource PDP estimation may be performed by measuring one pair (e.g., 2 REs) rather than 16 pairs. However, in some other embodiments, based on the resource allocation, the apparatus may measure two or more 2-port FD-CDM groups (e.g., two or more RE pairs) for per-CSI-RS resource PDP estimation, e.g., if the single-pair per-CSI- RS estimation fails. However, if more than three pairs are used, the cycle count may increase without significant improvement in performance. Still further, CDM groups may be associated with a CDM type. These CDM types include, without limitation, no CDM, FD-CDM2, CDM4 (e.g., FD2, TD2), or any future CDM type not yet specified by 3GPP.

[0048] At 606, the apparatus may perform a channel estimation procedure based on the per-CSI-RS resource PDP estimation. For example, referring to FIG. 3, using the single PDP estimation, channel estimation component 324 may perform channel estimation by applying the single PDP estimation to all of the 2-port CDM groups 402 in the CSI-RS resource.

[0049] In various aspects of the present disclosure, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or encoded as instructions or code on a non-transitory computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computing device, such as node 200 in FIG. 2. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, HDD, such as magnetic disk storage or other magnetic storage devices, Flash drive, SSD, or any other medium that can be usedAtty. Dkt. No. 10073-01-0171-PCTto carry or store desired program code in the form of instructions or data structures and that can be accessed by a processing system, such as a mobile device or a computer. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital video disc (DVD), and floppy disk where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0050] According to one aspect of the present disclosure, a method of wireless communication of a UE is provided. The method may include identifying, by at least one processor, a CSI-RS resource for channel estimation. The method may include performing, by the at least one processor, a per-CSI-RS resource PDP estimation. The method may include performing, by the at least one processor, a channel estimation procedure based on the per-CSI-RS resource PDP estimation.

[0051] In some embodiments, the CSI-RS resource includes a plurality of two-port CDM groups.

[0052] In some embodiments, the performing, by the at least one processor, the per-CSI- RS resource PDP estimation may include estimating the PDP for a first two-port CDM group of the plurality of two-port CDM groups.

[0053] In some embodiments, the performing, by the at least one processor, the channel estimation procedure based on the per-CSI-RS resource PDP estimation may include applying the PDP estimated for the first two-port CDM group to each of the plurality of two-port CDM groups in the CSI-RS resource.

[0054] In some embodiments, the performing, by the at least one processor, the channel estimation procedure based on the per-CSI-RS resource PDP estimation may include performing the channel estimation procedure based on the PDP applied to each of the plurality of two-port CDM groups in the CSI-RS resource.

[0055] In some embodiments, the CSI-RS resource may include sixteen two-port FD-CDM groups.

[0056] In some embodiments, the CSI-RS resource may be resource- wise quasi -located.

[0057] According to another aspect of the present disclosure, an apparatus for wireless communication of a UE is provided. The apparatus may include at least one processor. The apparatus may include memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform identifying a CSI-RS resource for channel estimation. The apparatus may include memory storing instructions, which when executedAtty. Dkt. No. 10073-01-0171-PCTby the at least one processor, may cause the at least one processor to perform performing a per- CSI-RS resource PDP estimation. The apparatus may include memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform performing a channel estimation procedure based on the per-CSI-RS resource PDP estimation.

[0058] In some embodiments, the CSI-RS resource may include a plurality of two-port CDM groups.

[0059] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform the performing the per- CSI-RS resource PDP estimation by estimating the PDP for a first two-port CDM group of the plurality of two-port CDM groups.

[0060] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform the performing the channel estimation procedure based on the per-CSI-RS resource PDP estimation by applying the PDP estimated for the first two-port CDM group to each of the plurality of two-port CDM groups in the CSI-RS resource.

[0061] In some embodiments, the memory storing instructions, which when executed by the at least one processor, may cause the at least one processor to perform the performing, by the at least one processor, the channel estimation procedure based on the per-CSI-RS resource PDP estimation by performing the channel estimation procedure based on the PDP applied to each of the plurality of two-port CDM groups in the CSI-RS resource.

[0062] In some embodiments, the CSI-RS resource may include sixteen two-port FD-CDM groups.

[0063] In some embodiments, the CSI-RS resource may be resource- wise quasi -located.

[0064] According to a further aspect of the present disclosure, a non-transitory computer- readable medium storing instructions for a UE is provided. The instructions, which when executed by at least one processor of the UE, cause the at least one processor to perform identifying a CSI- RS resource for channel estimation. The instructions, which when executed by at least one processor of the UE, cause the at least one processor to perform performing a per-CSI-RS resource PDP estimation. The instructions, which when executed by at least one processor of the UE, cause the at least one processor to perform performing a channel estimation procedure based on the per- CSI-RS resource PDP estimation.

[0065] In some embodiments, the CSI-RS resource may include a plurality of two-portAtty. Dkt. No. 10073-01-0171-PCTCDM groups.

[0066] In some embodiments, the instructions, which when executed by the at least one processor of the UE, may cause the at least one processor to perform the performing the per-CSI- RS resource PDP estimation by estimating the PDP for a first two-port CDM group of the plurality of two-port CDM groups.

[0067] In some embodiments, the instructions, which when executed by the at least one processor of the UE, may cause the at least one processor to perform the performing the channel estimation procedure based on the per-CSI-RS resource PDP estimation by applying the PDP estimated for the first two-port CDM group to each of the plurality of two-port CDM groups in the CSI-RS resource.

[0068] In some embodiments, the instructions, which when executed by the at least one processor of the UE, may cause the at least one processor to perform the performing, by the at least one processor, the channel estimation procedure based on the per-CSI-RS resource PDP estimation by performing the channel estimation procedure based on the PDP applied to each of the plurality of two-port CDM groups in the CSI-RS resource.

[0069] In some embodiments, the CSI-RS resource may include sixteen two-port FD-CDM groups.

[0070] The foregoing description of the specific embodiments will so reveal the general nature of the present disclosure that others can, by applying knowledge within the skill of the art, readily modify and / or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.

[0071] Embodiments of the present disclosure have been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

[0072] The Summary and Abstract sections may set forth one or more but not all exemplaryAtty. Dkt. No. 10073-01-0171-PCTembodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way.

[0073] Various functional blocks, modules, and steps are disclosed above. The particular arrangements provided are illustrative and without limitation. Accordingly, the functional blocks, modules, and steps may be re-ordered or combined in different ways than in the examples provided above. Likewise, certain embodiments include only a subset of the functional blocks, modules, and steps, and any such subset is permitted. The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.Atty. Dkt. No. 10073-01-0171-PCT

Claims

WHAT IS CLAIMED IS:

1. A method of wireless communication of a user equipment (UE), comprising: identifying, by at least one processor, a channel state information (CSI)-reference signal (RS) (CSI-RS) resource for channel estimation; performing, by the at least one processor, a per-CSLRS resource power delay profile (PDP) estimation; and performing, by the at least one processor, a channel estimation procedure based on the per- CSLRS resource PDP estimation.

2. The method of claim 1, wherein the CSI-RS resource includes a plurality of two-port code division multiplexed (CDM) groups.

3. The method of claim 2, wherein the performing, by the at least one processor, the per-CSL RS resource PDP estimation comprises: estimating the PDP for a first two-port CDM group of the plurality of two-port CDM groups.

4. The method of claim 3, wherein the performing, by the at least one processor, the channel estimation procedure based on the per-CSLRS resource PDP estimation comprises: applying the PDP estimated for the first two-port CDM group to each of the plurality of two-port CDM groups in the CSI-RS resource.

5. The method of claim 4, wherein the performing, by the at least one processor, the channel estimation procedure based on the per-CSLRS resource PDP estimation comprises: performing the channel estimation procedure based on the PDP applied to each of the plurality of two-port CDM groups in the CSI-RS resource.

6. The method of claim 1, wherein the CSLRS resource includes sixteen two-port frequency domain (FD)-CDM groups.

7. The method of claim 1, wherein the CSLRS resource is resource-wise quasi -located.Atty. Dkt. No. 10073-01-0171-PCT8. An apparatus for wireless communication of a user equipment (UE), comprising: at least one processor; and memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform: identifying a channel state information (CSI)-reference signal (RS) (CSI-RS) resource for channel estimation; performing a per-CSI-RS resource power delay profile (PDP) estimation; and performing a channel estimation procedure based on the per-CSI-RS resource PDP estimation.

9. The apparatus of claim 8, wherein the CSI-RS resource includes a plurality of two-port code division multiplexed (CDM) groups.

10. The apparatus of claim 9, wherein the memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform the performing the per- CSI-RS resource PDP estimation by: estimating the PDP for a first two-port CDM group of the plurality of two-port CDM groups.

11. The apparatus of claim 10, wherein the memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform the performing the channel estimation procedure based on the per-CSI-RS resource PDP estimation by: applying the PDP estimated for the first two-port CDM group to each of the plurality of two-port CDM groups in the CSI-RS resource.

12. The apparatus of claim 11, wherein the memory storing instructions, which when executed by the at least one processor, cause the at least one processor to perform the performing, by the at least one processor, the channel estimation procedure based on the per-CSI-RS resource PDP estimation by: performing the channel estimation procedure based on the PDP applied to each of the plurality of two-port CDM groups in the CSI-RS resource.Atty. Dkt. No. 10073-01-0171-PCT13. The apparatus of claim 8, wherein the CSI-RS resource includes sixteen two-port frequency domain (FD)-CDM groups.

14. The apparatus of claim 8, wherein the CSI-RS resource is resource-wise quasi-located.

15. A non-transitory computer-readable medium storing instructions, which when executed by at least one processor of a user equipment (UE), cause the at least one processor to perform: identifying a channel state information (CSI)-reference signal (RS) (CSI-RS) resource for channel estimation; performing a per-CSI-RS resource power delay profile (PDP) estimation; and performing a channel estimation procedure based on the per-CSI-RS resource PDP estimation.

16. The non-transitory computer-readable medium of claim 15, wherein CSI-RS resource includes a plurality of two-port code division multiplexed (CDM) groups.

17. The non-transitory computer-readable medium of claim 16, wherein the instructions, which when executed by the at least one processor of the UE, cause the at least one processor to perform the performing the per-CSI-RS resource PDP estimation by: estimating the PDP for a first two-port CDM group of the plurality of two-port CDM groups.

18. The non-transitory computer-readable medium of claim 17, wherein the instructions, which when executed by the at least one processor of the UE, cause the at least one processor to perform the performing the channel estimation procedure based on the per-CSI-RS resource PDP estimation by: applying the PDP estimated for the first two-port CDM group to each of the plurality of two-port CDM groups in the CSI-RS resource.

19. The non-transitory computer-readable medium of claim 18, wherein the instructions, which when executed by the at least one processor of the UE, cause the at least one processor to perform the performing, by the at least one processor, the channel estimation procedure based on the per-Atty. Dkt. No. 10073-01-0171-PCTCSI-RS resource PDP estimation by: performing the channel estimation procedure based on the PDP applied to each of the plurality of two-port CDM groups in the CSI-RS resource.

20. The non-transitory computer-readable medium of claim 15, wherein the CSI-RS resource includes sixteen two-port frequency domain (FD)-CDM groups.Atty. Dkt. No. 10073-01-0171-PCT

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