Enhanced apparatus and methods to support HST-SFN deployment scenarios

Abstract

A device, such as a UE and a transmit / receive point (TRP), for providing network-assisted frequency offset compensation in a high-speed train single-frequency network (HST-SFN) is disclosed. The device includes a receiver that receives a first reference signal and a second reference signal transmitted from a first TRP via a wireless network. The first reference signal corresponds to the QCL RS of the second reference signal. The device receiver determines delay spread and average delay information of the path between the first TRP and the device based on the first reference signal. The device receiver also receives a third reference signal from the second TRP, which includes Doppler frequency shift and Doppler spread information and corresponds to the QCL RS of a fourth reference signal transmitted from the second TRP, or corresponds to the second reference signal transmitted from the first TRP in an SFN manner.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 090,175, filed October 9, 2020; U.S. Provisional Patent Application No. 63 / 130,405, filed December 23, 2020; U.S. Provisional Patent Application No. 63 / 159,443, filed March 10, 2021; and U.S. Provisional Patent Application No. 63 / 164,807, filed March 23, 2021, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] The topics disclosed herein generally relate to wireless communication systems. More specifically, this topic relates to systems and methods for transmission in High-Speed ​​Trains Single-Frequency Network (HST-SFN). Background Technology

[0004] In current high-speed train (HST) scenarios utilizing single-frequency networks (SFN), dynamic handover between transmit and receive points (TRPs) requires additional tracking reference signals (TRS) and channel state information-reference signals (CSI-RS) dedicated to SFN transmission to derive quasi-co-located (QCL) characteristics, incurring significant resource allocation overhead. Furthermore, in current HST scenarios using SFN, the TRS and corresponding demodulation reference signal (DMRS) ports may traverse composite channels from the major path of each TRP, potentially leading to very high user equipment (UE) complexity. Additionally, in HST environments, high UE mobility can result in negative Doppler offsets moving away from one TRP and positive Doppler offsets moving towards another, and since each TRP uses an independent local oscillator, Doppler offsets may be based on different baseband frequencies. Therefore, in the HST-SFN scenario, the UE may need very high complexity in order to accurately estimate the significantly different Doppler frequency shifts based on the synthetic TRS, and as a result, a Wiener filter can be used on the estimated Doppler frequency shifts to improve the channel estimation performance. Summary of the Invention

[0005] Example embodiments provide an apparatus that can include a receiver configured to receive a first reference signal and a second reference signal transmitted from a first TRP over a wireless network, where the first reference signal corresponds to a Quasi-Co-Location Reference Signal (QCL RS) of the second reference signal, and the receiver can be further configured to determine delay spread and average delay information of a path between the first TRP and the apparatus based on the first reference signal. In one embodiment, the first reference signal can be a TRS and the second reference signal can be a Physical Downlink Shared Channel (PDSCH) DMRS. In another embodiment, the first reference signal can be one of a TRS and a Synchronization Signal Block (SSB), and the second reference signal can be a TRS. In yet another embodiment, the receiver can be further configured to receive a third reference signal from a second TRP, where the third reference signal can include Doppler shift and Doppler spread information, and can correspond to a QCL RS of a fourth reference signal transmitted from the second TRP or can correspond to the second reference signal transmitted from the first TRP in SFN manner. In yet another embodiment, the second TRP can be a reference TRP, the first TRP can be a non-reference TRP, and the first reference signal can pre-compensate for Doppler shift at the apparatus relative to the second TRP in a HST scenario. In one embodiment, the second reference signal can be associated with two Transmission Configuration Indicator (TCI) states corresponding to the first reference signal and the third reference signal. In another embodiment, the receiver can be further configured to receive a Physical Downlink Control Channel (PDCCH) DMRS associated with the two TCI states from the first TRP and the second TRP, and where the receiver can determine a TCI state of a PDSCH DMRS scheduled by the PDCCH to be one of the two TCI states. In one embodiment, the receiver can be further configured to receive a fifth reference signal transmitted from the first TRP and the second TRP over the wireless network, where the fifth reference signal can include a dual-port Phase Tracking Reference Signal (PTRS), where a first port of the dual-port PTRS can convey phase tracking information of the first TRP and a second port of the dual-port PTRS can convey phase tracking information of the second TRP. In yet another embodiment, the receiver can be further configured to receive a control message transmitted from the first TRP over the wireless network to dynamically update a configuration of one of the first reference signal and the second reference signal, and the receiver can determine at least periodicity information for the one of the first reference signal and the second reference signal based on the control message based on a change in movement of the apparatus relative to the first TRP.In yet another embodiment, the receiver can also be configured to receive a control message transmitted over the wireless network from the first TRP, wherein the control message can dynamically update the quasi co-location information of one of the first reference signal and the second reference signal, and the receiver can determine the information for at least one of the Doppler shift, the Doppler spread, the average delay, the delay spread, and the spatial receiver parameters based on the control message based on a change in the device's movement relative to the first TRP.

[0006] One example embodiment provides a wireless network that can include a first TRP that can include a first transmitter configured to transmit, over the wireless network, a first reference signal and a second reference signal to a device, the first reference signal corresponding to a QCL RS of the second reference signal and can be used by the device to determine delay spread and average delay information of a path between the first TRP and the device. In one embodiment, the first reference signal can be a TRS signal and the second reference signal can be a PDSCH DMRS. In another embodiment, the first reference signal can be a TRS and a SSB and the second reference signal can be a TRS. In yet another embodiment, the wireless network can further include a second TRP that can include a second transmitter configured to transmit a third reference signal and a fourth reference signal, where the third reference signal can include Doppler shift and Doppler spread information and can correspond to a QCL RS of the fourth reference signal transmitted from the second transmitter or can correspond to the second reference signal transmitted from the first TRP in SFN manner. In yet another embodiment, the second TRP can be a reference TRP and the first TRP can be a non-reference TRP and the first reference signal can pre-compensate for Doppler shift at the device relative to the second TRP in an HST scenario. In one embodiment, the second reference signal can be associated with two TCI states corresponding to the first reference signal and the third reference signal. In another embodiment, the first TRP and the second TRP can each transmit, to the device, a PDCCH DMRS associated with the two TCI states, from which the device can determine a TCI state of a PDSCH DMRS scheduled by the PDCCH to be one of the two TCI states. In one embodiment, the first TRP and the second TRP can be configured to transmit, over the wireless network, a fifth reference signal to the device, where the fifth reference signal can include a dual-port PTRS, where a first port of the dual-port PTRS can convey phase tracking information of the first TRP and a second port of the dual-port PTRS can convey phase tracking information of the second TRP. In yet another embodiment, the first TRP can be configured to transmit, to the device, a control message transmitted over the wireless network to dynamically update a configuration of one of the first reference signal and the second reference signal and the device can determine, from the control message, at least periodicity information for the one of the first reference signal and the second reference signal based on a change in movement of the device relative to the first TRP. In one embodiment, the first TRP can be further configured to transmit, to the device, a control message transmitted over the wireless network that can dynamically update quasi-co-location information of one of the first reference signal and the second reference signal and can include at least one of Doppler shift, Doppler spread, average delay, delay spread, and spatial receiver parameters based on a change in movement of the device relative to the first TRP. BRIEF DESCRIPTION OF DRAWINGS

[0007] Aspects of the subject disclosed herein will now be described with reference to the example embodiments illustrated in the drawings, in which:

[0008] Figure 1 An example embodiment of a wireless communication network according to the subject disclosed herein is depicted;

[0009] Figure 2 An example embodiment of a base station device according to the subject disclosed herein is depicted;

[0010] Figure 3 An example embodiment of a user equipment according to the subject disclosed herein is depicted;

[0011] Figure 4A An example embodiment of a downlink slot structure is depicted;

[0012] Figure 4B An example embodiment of an uplink slot structure for physical uplink shared channel transmission or physical uplink control channel transmission is depicted;

[0013] Figure 5A A block diagram of an example embodiment of a transmitter structure using OFDM according to the subject disclosed herein is depicted;

[0014] Figure 5B A block diagram of an example embodiment of an OFDM receiver structure according to the subject disclosed herein is depicted;

[0015] Figure 6 An example HST-SFN environment in which coherent joint transmission can occur is depicted;

[0016] Figure 7 An example RS overhead on an example bandwidth is shown for the configuration of QCL reference RS in SFN transmission of three TRPs;

[0017] Figure 8 A separate QCL RS of three TRPs sufficient for dynamic switching among the three TRPs is shown;

[0018] Figures 9A-9C Three dynamic switching scenarios in an example HST-SFN environment including a first TRP, a second TRP, and a UE are respectively depicted;

[0019] Figures 10A-10C A first aspect according to the first embodiment of the subject disclosed herein is depicted, in which for all dynamic switching transmission cases, the predetermined TRP known to the UE is always the frequency offset pre-compensated reference on the gNB side;

[0020] Figures 11A-11C(2)A second aspect is depicted in accordance with an embodiment of the subject matter disclosed herein, in which a predetermined TRP known to the UE is always the gNB side of the frequency offset pre-compensation for all dynamic switching transmission cases;

[0021] Figures 12A-12C Frequency offset compensation schemes are shown for three dynamic switching cases in accordance with the subject matter disclosed herein, in which each TRP is responsible for its own corresponding frequency offset pre-compensation;

[0022] Figure 13 A fourth aspect is depicted in accordance with a first embodiment of network frequency offset pre-compensation in accordance with the subject matter disclosed herein, in which the network frequency offset pre-compensation uses a three-step procedure with implicit UE indication;

[0023] Figure 14 A fifth aspect is depicted in accordance with a first embodiment of network frequency offset pre-compensation in accordance with the subject matter disclosed herein, in which the network frequency offset pre-compensation uses a two-step procedure starting with UL RS transmission;

[0024] Figure 15A and Figure 15B Example embodiments of a three-step procedure and a two-step procedure for network frequency offset pre-compensation in accordance with the subject matter disclosed herein are depicted, in which the network frequency offset pre-compensation provides TRP-specific frequency offset pre-compensation for each TRP independently;

[0025] Figure 16A and Figure 16B Second embodiments of a three-step procedure and a two-step procedure for network frequency offset pre-compensation in accordance with the subject matter disclosed herein are depicted, in which the network frequency offset pre-compensation uses SFN manner TRS transmission with implicit UE indication;

[0026] Figure 17A and Figure 17B Example embodiments of a three-step procedure and a two-step procedure in accordance with the subject matter disclosed herein are depicted, which use SFN manner TRS transmission in which network pre-compensation is provided for each TRP independently;

[0027] Figure 18 Another aspect is depicted in accordance with a second embodiment of the subject matter disclosed herein, in which the second embodiment combines SFN and TRP-specific TRS transmission for a three-step procedure;

[0028] Figure 19 Still another aspect is shown in accordance with a second embodiment of the subject matter disclosed herein, which combines SFN and TRP-specific TRS transmission with network pre-compensation of Doppler shift provided for each TRP independently;

[0029] Figure 20QCL relationships of TRS reference signals of semi-persistent resources that can be configured through a media access control (MAC) control element (CE) triggering procedure are shown in accordance with the subject matter disclosed herein;

[0030] Figure 21 Reuse of Rel-17 enhanced TCI state activation / deactivation MAC CE structure is shown;

[0031] Figure 22 A block diagram of an example embodiment of a UE receiver for demodulating and decoding received data is shown;

[0032] Figure 23 An example block diagram of a UE receiver in accordance with the subject matter disclosed herein is shown;

[0033] Figure 24 A block diagram of an example embodiment of a UE receiver with separate receiver chains in accordance with the subject matter disclosed herein is shown;

[0034] Figure 25 And Figure 26 Single DCI and multiple DCI M-TRP transmission schemes in accordance with the subject matter disclosed herein are depicted respectively;

[0035] Figure 27A Schemes in accordance with the subject matter disclosed herein are depicted in which one PDCCH candidate (in a given SS set) can be associated with two TCI states of a CORESET;

[0036] Figure 27B Schemes in accordance with the subject matter disclosed herein are depicted in which two sets of PDCCH candidates (in a given SS set) can be associated with two TCI states of a CORESET respectively;

[0037] Figure 27C Schemes in accordance with the subject matter disclosed herein are depicted in which two sets of PDCCH candidates can be associated with two corresponding SS sets, where the two SS sets can be associated with a CORESET and each SS set can be associated with only one TCI state of the CORESET;

[0038] Figures 28A-28D Examples of the repetition schemes disclosed herein are depicted;

[0039] Figure 29 Examples of PDSCH scheduling and UE behavior in accordance with method 10 disclosed herein are depicted;

[0040] Figure 30 Examples of method 11 in accordance with the subject matter disclosed herein are depicted;

[0041] Figure 31An example of method 12 according to the subject matter disclosed herein is depicted;

[0042] Figure 32 An example of method 13 according to the subject matter disclosed herein is depicted;

[0043] Figure 33 An example of intra-slot TDM according to the subject matter disclosed herein is depicted;

[0044] Figure 34 An example of multiple contiguous chunks with alternating TCI states (where L=2) according to the subject matter disclosed herein is depicted;

[0045] Figure 35 An example of multiple contiguous slots with alternating TCI states based on inter-slot TDM case 2 according to the subject matter disclosed herein is depicted; and

[0046] Figure 36 An example of FDM PDSCH scheme according to the subject matter disclosed herein is depicted. DETAILED DESCRIPTION

[0047] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the disclosure. However, it will be understood by those skilled in the art that the disclosed aspects can be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the subject matter disclosed herein.

[0048] References throughout this specification to “one embodiment” or “an embodiment” mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” or “in an embodiment” or “according to one embodiment” (or other similar phrases) in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In this regard, the word “exemplary” means “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. In addition, in one or more embodiments, the particular features, structures, or characteristics can be combined in any suitable manner. Moreover, depending on the context, singular terms can include pluralities or plural terms can include singularities. Similarly, hyphenated terms, such as “two- dimensional,” “pre-determined,” “pixel-specific,” etc., can occasionally be used in conjunction with corresponding non-hyphenated versions, such as “two dimensional,” “pre determined,” “pixel specific,” etc., and capitalized terms, such as “Counter Clock,” “Row Select,” “PIXOUT,” etc., can occasionally be used in conjunction with corresponding non-capitalized versions, such as “counter clock,” “row select,” “pixout,” etc. Such occasional use of the occasionally interchangeable versions is not to be taken as in any way inconsistent with each other.

[0049] Furthermore, depending on the context, singular terms can include pluralities or plural terms can include singularities. It will also be noted that various graphics (including component diagrams) shown and discussed herein are merely illustrative and are not drawn to scale. For example, the dimensions of some elements can be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and / or analogous elements.

[0050] The terminology used herein is for the purpose of describing some example embodiments only and is not intended to be limiting of the claimed subject matter. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0051] It will be understood that when an element or layer is referred to as being "on" or "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0052] As used herein, the terms "first," "second," and the like, are used as labels for nouns that they follow and do not necessarily describe a relationship between the referenced objects. Further, the terms "first," "second," and the like, are used interchangeably with the terms "one," "another," and "at least one," unless explicitly defined otherwise. Additionally, the use of the terms "top," "bottom," "front," "back," and the like, are used for illustration and discussion, and do not limit the scope of the disclosed embodiments. The terms "left," "right," "front," "back," "forward," "backward," "vertical," "horizontal," and the like, are used to illustrate relative positions on and / or between elements, components, blocks, circuits, units, or modules. However, such use is only made for simplicity, clarity and ease of discussion, and is not intended to limit the scope of the disclosed embodiments, nor is it intended to limit the position of the components or units to only positions as described. Further, the use of the terms "first," "second," and the like, can be used to describe a variety of elements, components, blocks, circuits, units, or modules, and does not necessarily limit the scope of the disclosed embodiments to only those with such elements, components, blocks, circuits, units, or modules.

[0053] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0054] As used herein, the term “module” refers to any combination of software, firmware, and / or hardware configured to provide the functionality described herein with respect to the module. For example, software can be embodied in software packages, code, and / or instructions sets or instruction sets, and the term “hardware” as used herein in any embodiment described herein can include, for example, individually or in any combination, assembly, hardwired circuitry, programmable circuitry, state machine circuitry, and / or firmware that stores instructions executed by the programmable circuitry. These modules can collectively or individually be embodied as circuitry forming a portion of a larger system, such as, but not limited to, an integrated circuit (IC), a system on a chip (SoC), an assembly, and / or the like.

[0055] The detailed description set forth below describes various embodiments of the subject matter disclosed herein, by way of example and not by way of limitation. Figures 1-36 The various embodiments described for the purpose of illustration only and should not be construed as limiting the scope of the subject matter disclosed herein in any way. It is to be understood that the subject matter disclosed herein can be implemented in any suitably arranged system or device.

[0056] At least the following documents are hereby incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 38.211 v15.6.0, “NR; Physical channels and modulation”; 3GPP TS 38.212 v15.6.0, “NR; Multiplexing and channel coding”; 3GPP TS 38.213 v15.6.0, “NR; Physical layer procedures for control”; 3GPP TS 38.214 v15.6.0, “NR; Physical layer procedures for data”; 3GPP TS 38.321 v15.6.0, “NR; Medium Access Control (MAC) protocol specification”; and 3GPP TS 38.331 v15.6.0, “NR; Radio Resource Control (RRC) protocol specification”.

[0057] Figure 1 FIG. 5 depicts various example embodiments implemented in wireless communication systems and the use of orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication techniques. Figure 1 The description of FIG. 5 is not meant to imply a physical or architectural limitation to the manner in which different embodiments can be implemented. The various embodiments of the subject matter disclosed herein can be implemented in any suitably-arranged communication system.

[0058] Figure 1 An example embodiment of a wireless communication network 100 in accordance with the subject matter disclosed herein is depicted. Figure 1The example embodiments of the wireless network depicted herein are for illustrative purposes only. Other embodiments of the wireless network 100 may be used without departing from the principles of the subject matter disclosed herein.

[0059] like Figure 1 As shown, the wireless network 100 includes gNB 101 (e.g., a base station), gNB 102, and gNB 103. gNB 101 can communicate with gNB 102 and gNB 103. gNB 101 can also communicate with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0060] gNB 102 can provide wireless broadband access to network 130 to a first plurality of UEs within its coverage area 120. The first plurality of UEs may include UE 111, which may be located in a small business (SB); UE 112, which may be located in an enterprise (S); UE 113, which may be located in a WiFi hotspot (HS); UE 114, which may be located in a first residence (R); UE 115, which may be located in a second residence (R); and UE 116, which may be a mobile device (M), such as, but not limited to, a cellular phone, a wireless laptop, a wireless PDA, etc. gNB 103 can provide wireless broadband access to network 130 to a second plurality of UEs within its coverage area 125. The second plurality of UEs may include UE 115 and UE 116. In some embodiments, one or more of gNBs 101-103 may communicate with each other and with UEs 111-116 using 5G / NR, LTE, LTE-A, WiMAX, WiFi, and / or other wireless communication technologies.

[0061] 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 a transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G / NR base station (gNB), a microcell, a femtocell, a WiFi access point (AP), or other wirelessly enabled devices. Base stations can provide wireless access to a PLMN, a 5G / NR access and mobility function (AMF), a 5G / NR core access and mobility function (Core-AMF), or other networks using one or more wireless communication protocols, such as 5G / NR 3GPP New Radio Interface / Access (NR), Long-Term Evolution (LTE), LTE-Advanced (LTE-A), High Speed Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac / etc. For the sake of convenience, the terms "BS" and "TRP" can be used interchangeably herein to refer to network infrastructure components that provide wireless access to remote terminals. Further, 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" can be used interchangeably herein to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as, but not limited to, a mobile phone or smart phone) or is normally considered a stationary device (such as, but not limited to, a desktop computer or a vending machine).

[0062] Dotted lines depict the approximate extents of the coverage areas 120 and 125, which are depicted as approximately circular for the purposes of illustration and explanation only. It is clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, can have other shapes, including irregular shapes, depending on the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.

[0063] As described in more detail below, one or more of the UEs 111-116 can include circuitry, programming or a combination thereof for efficient control signaling designed to improve resource utilization. In certain embodiments, one or more of the gNBs 101-103 can include circuitry, programming or a combination thereof for efficient control signaling designed to improve resource utilization.

[0064] Although Figure 1 One example of a wireless network is depicted, but Figure 1Various modifications can be made. For example, the wireless network 100 can include any number of gNBs and any number of UEs in any suitable arrangement. Furthermore, gNB 101 can communicate directly with any number of UEs and provide these UEs with wireless broadband access to network 130. Similarly, each gNB 102-103 can communicate directly with network 130 and provide the UEs with direct wireless broadband access to network 130. Additionally, gNBs 101, 102, and / or 103 can provide access to other or additional external networks, such as, but not limited to, external telephone networks or other types of data networks.

[0065] Figure 2 An example embodiment of gNB 102 based on the subject matter disclosed herein is depicted. Figure 2 The embodiments of gNB 102 depicted are for illustrative purposes only, and Figure 1 gNBs 101 and 103 can have the same or similar configurations. However, gNBs have a wide variety of configurations, and it should be understood that... Figure 2 The scope of the subject matter disclosed herein is not limited to any particular implementation of gNB.

[0066] like Figure 2 As shown, gNB 102 may include multiple antennas 201a-201n, multiple radio frequency (RF) transceivers 202a-202n, receive (RX) processing circuitry 203, and transmit (TX) processing circuitry 204. gNB 102 may also include a controller / processor 205, a memory 206, and / or a backhaul or network interface 207. TX processing circuitry 204 may include a controller / processor (not shown) that controls TX processing circuitry 204 to perform the transmit-related functions disclosed herein. Alternatively, controller / processor 205 may be configured to control TX processing circuitry 204 to perform the transmit-related functions disclosed herein.

[0067] RF transceivers 202a-202n can receive RF signals input from antennas 201a-201n. The received RF signals can be signals transmitted by a UE in network 100. RF transceivers 202a-202n can down-convert the input RF signals to generate IF or baseband signals. The IF or baseband signals can be sent to RX processing circuitry 203, which generates processed baseband signals by filtering, decoding, and / or digitizing the baseband or IF signals. RX processing circuitry 203 can then send the processed baseband signals to controller / processor 205 for further processing.

[0068] The TX processing circuitry 204 can receive analog or digital data (such as, but not limited to, voice data, web data, e-mail, or interactive video game data) from the controller / processor 205. The TX processing circuitry 204 can process the output baseband data (such as by encoding, multiplexing, and / or digitizing the data) to generate a processed baseband or IF signal. The RF transceivers 202a-202n can receive the output processed baseband or IF signal from the TX processing circuitry 204 and can up-convert the baseband or IF signal to an RF signal that is transmitted via the antennas 201a-201n. The TX processing circuitry 204 can be configured such that one or more beam(s) are transmitted via the antennas 201a-201n.

[0069] The controller / processor 205 can include one or more processors or other processing devices to manage the overall operation of the gNB 102. For example, the controller / processor 205 can control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 202a-202n, the RX processing circuitry 203, and the TX processing circuitry 204 in accordance with well-known principles. The controller / processor 205 can support additional functions as well, such as more advanced wireless communication functions. For instance, the controller / processor 205 can support beam forming or directional routing operations in which the incoming or outgoing signals from multiple antennas 201a-201n are weighted and combined. The controller / processor 205 can support any of a variety of other functions as well.

[0070] The controller / processor 205 is also capable of executing programs and other processes resident in the memory 206, such as an operating system (OS). The controller / processor 205 can move data into or out of the memory 206 as required by the processes executing on the controller / processor 205. Portions of the memory 206 can be used to store program codes, operating systems, application programs, and / or other information, which are loaded by the controller / processor 205 as necessary.

[0071] The controller / processor 205 can be used to direct the operation at the gNB 102 by providing, for example, instructions and receiving measurements. The controller / processor 205 can also be used to determine a reference signal received power (RSRP) and / or a reference signal received quality (RSRQ). The controller / processor 205 can also be used to perform or direct the execution of other processes for the techniques described herein. The controller / processor 205 can be replaced with a memory that stores program codes for the techniques described herein and that triggers processing of the memories’ contents by the controller / processor 205 or another processor.

[0072] Although Figure 2 various changes can be made to the gNB 102 depicted Figure 2 For example, the gNB 102 could include any number of each component shown in the example figure. As a particular example, an access point could include a number of interfaces 207, and the controller / processor 205 could support routing Figure 2 functionality to route data between different network addresses. As another particular example, while shown as including a single instance of the TX processing circuitry 204 and a single instance of the RX processing circuitry 203, the gNB 102 could include multiple instances of each (such as one per RF transceiver, one per antenna, etc.). Also, various components in Figure 2 may be combined, further subdivided, or omitted and additional components can be added according to particular needs. It should be understood that Figure 2 The example gNB 102 depicted in

[0073] Figure 3 An example embodiment of a UE 116 according to the subject matter disclosed herein is depicted. Figure 3 The embodiment of the UE 116 depicted in Figure 1 The UEs 111-115 can have the same or similar configuration. However, UEs can have a wide variety of configurations and Figure 3 without limiting the UE to any particular implementation of a UE.

[0074] As Figure 3As shown, the UE 116 can include one or more antennas 301, an RF transceiver 302, TX processing circuitry 303, a microphone 304, and RX processing circuitry 305. The UE 116 can also include a speaker 306, a processor 307, an input / output (I / O) interface 308, a touchscreen 309 (or other input device), a display 310, and a memory 311. The memory 311 can include an OS 312 and one or more applications 313. The TX processing circuitry 303 can include a controller / processor that is not shown, which can be configured to control the TX processing circuitry 303 to perform the transmission-related functions disclosed herein. Alternatively, the processor 307 can be configured to control the TX processing circuitry 303 to perform the transmission-related functions disclosed herein.

[0075] The RF transceiver 302 can receive, from the antennas 301, incoming RF signals transmitted by gNBs of the network 100. The RF transceiver 302 can down-convert the incoming RF signals to generate intermediate frequency (IF) or baseband signals. The IF or baseband signals can be sent to the RX processing circuitry 305, which generates processed baseband signals by filtering, decoding, and / or digitizing the baseband or IF signals. The RX processing circuitry 305 can transmit the processed baseband signals to the speaker 306, such as for voice data, or to the processor 307 for further processing, such as for web browsing data.

[0076] The TX processing circuitry 303 can receive analog or digital voice data from the microphone 304, or other outgoing baseband data (such as web browsing data, e-mail, or interactive video game data) from the processor 307. The TX processing circuitry 303 can encode, multiplex, and / or digitize the outgoing baseband data to generate processed baseband or IF signals. The RF transceiver 302 can receive the outgoing processed baseband or IF signals from the TX processing circuitry 303 and up-convert the baseband or IF signals to RF signals that are transmitted via the one or more antennas 301. The TX processing circuitry 303 can be configured to transmit one or more beams from the one or more antennas 301.

[0077] The processor 307 can include one or more processors or other processing devices and can execute the OS 312 stored in the memory 311 in order to control the overall operation of the UE 116. For example, the processor 307 can control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver 302, TX processing circuitry 303, and RX processing circuitry 305 in accordance with well-known principles. In some embodiments, the processor 307 can be at least one microprocessor or microcontroller.

[0078] The processor 307 is also capable of executing other processes and programs resident in the memory 311, such as processes for beam management. The processor 307 can move data into or out of memory 311 as required by an executing process. In some embodiments the processor 307 can be configured to execute the applications 313 based on the OS 312 or in response to signals received from gNBs or from an operator. The processor 307 can also be coupled to the I / O interface 308, which provides the UE 116 with the ability to connect to other devices such as, for example, laptop computers and handheld computers. The I / O interface 308 is the communication path between these accessories and the processor 307.

[0079] The processor 307 can also be coupled to the touchscreen 309 and the display 310. The touchscreen 309 can be used by the operator of the UE 116 to input data to the UE 116. The display 310 can be a liquid crystal display, light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as from web sites.

[0080] The memory 311 can be coupled to the processor 307. One portion of the memory 311 can include a RAM, and another portion of the memory 311 can include a Flash memory or other ROM.

[0081] Although Figure 3 one example embodiment of a UE 116 is depicted, various changes can be made Figure 3 to the depicted example without departing from the scope of the subject matter. For example, Figure 3 various components in the UE 116 can be combined, further subdivided, or omitted and additional components can be added according to particular needs. As a specific example, the processor 307 can be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, while the Figure 3 UE 116 is depicted as a mobile telephone or smartphone, the UE can be configured to operate as other types of mobile or stationary devices. It should be understood that Figure 3 the example UE 116 depicted in the figures can be configured to provide any and all of the functionality of a UE described herein.

[0082] 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 / NR or pre-5G / NR communication system. Therefore, the 5G / NR or pre-5G / NR communication system can also be referred to as a "beyond 4G network" or a "5G network." The 5G / NR communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60 GHz bands, so as to alleviate spectral scarcity and enable higher data rates. To decrease the propagation loss of the radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed for use in 5G / NR communication systems. In addition, in 5G / NR communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, a technology for coordination between cells, a coordinated multi-point (CoMP) technology, interference mitigation technology, network slicing, device-to-device (D2D) communication, wireless backhaul, a mobile network, a mobile core network, a technology for moving connection, a technology for reducing latency, a technology for improving reliability, and the like.

[0083] A communication system can include a downlink (DL) referring to transmission from a base station or one or more transmission points to a UE and an uplink (UL) referring to transmission from a UE to a base station or one or more reception points.

[0084] A unit for DL signaling or UL signaling on a cell can be referred to as a slot, and can include one or more symbols. A symbol can also serve as an additional time unit. A frequency (or bandwidth (BW)) unit can be referred to as a resource block (RB). One RB can include a plurality of subcarriers (SCs). For example, one slot can have a duration of 0.5 milliseconds or 1 millisecond, include 14 symbols, and one RB can include 12 SCs with an inter-SC spacing of 30 kHz or 15 kHz, respectively. A unit of one RB in frequency and one symbol in time can be referred to as a physical RB (PRB).

[0085] A DL signal can include a data signal conveying information content, a control signal conveying DL control information (DCI), and a reference signal (RS) that can also be referred to as a pilot signal. A gNB transmits data information or DCI through a corresponding physical DL shared channel (PDSCH) or a physical DL control channel (PDCCH). The PDSCH or the PDCCH can be transmitted over a variable number of slot symbols including one slot symbol. For brevity, a DCI format scheduling a PDSCH reception by a UE can be referred to as a DL DCI format, while a DCI format scheduling a physical UL shared channel (PUSCH) transmission from a UE is referred to as a UL DCI format.

[0086] A gNB can transmit one or more of multiple types of RS including channel state information RS (CSI-RS) and demodulation RS (DM-RS). The CSI-RS can be used primarily for a UE to perform measurements and provide channel state information (CSI) to the gNB. For channel measurements, non-zero-power CSI-RS (NZP CSI-RS) resources can be used. For interference measurement reporting (IMR), CSI interference measurement (CSI-IM) resources can be used. A CSI process can include NZP CSI-RS and CSI-IM resources.

[0087] A UE can determine CSI-RS transmission parameters through DL control signaling or higher layer signaling, such as radio resource control (RRC) signaling, from a gNB. Transmission instances of a CSI-RS can be indicated by DL control signaling or configured by higher layer signaling. Typically, a DM-RS can be transmitted only within a BW of a corresponding PDCCH or PDSCH, and a UE can use the DM-RS to demodulate data or control information.

[0088] Figure 4A An example embodiment of a DL slot structure 400 is depicted in accordance with the subject matter disclosed herein. Figure 4A The example embodiment of the DL slot structure 400 depicted in Figure 4A The scope of the subject matter disclosed herein is not limited to any particular implementation. It should be noted that in the DL slot structure 400 as described below, DCI information does not need to be positioned as depicted in Figure 4A but can be positioned elsewhere as appropriate.

[0089] As Figure 4A depicted, a DL slot 401 can include symbols 402 in which a gNB can transmit, for example, data information, DCI, or DM-RS. A DL system BW can include RBs. Each RB can include SCs. A UE can be allocated M PDSCH RBs for a total of SCs 403 for a PDSCH transmission BW. PDCCH signals conveying DCI can be transmitted through control channel elements (CCEs) that extend substantially across the DL system BW. A first slot symbol 404 can be used by a gNB to transmit PDCCH. A second slot symbol 405 can be used by a gNB to transmit PDCCH or PDSCH. The remaining slot symbols 406 can be used by a gNB to transmit PDSCH and CSI-RS. In some slots, a gNB can also transmit synchronization signals and channels conveying system information, such as synchronization signal and primary broadcast channel (SS / PBCH) blocks.

[0090] The UL signals can also include data signals conveying information content, control signals conveying UL control information (UCI), DM-RS associated with data or UCI demodulation, sounding RS (SRS) to enable gNB to perform UL channel measurement, and random access (RA) preamble to enable the UE to perform random access. The UE can transmit data information or UCI through a respective physical UL shared channel (PUSCH) or physical UL control channel (PUCCH). The PUSCH or PUCCH can be transmitted over a variable number of symbols in a slot including one symbol. When the UE transmits data information and UCI simultaneously, the UE can multiplex both in the PUSCH.

[0091] The UCI can include hybrid automatic repeat request acknowledgement (HARQ-ACK) information indicating correct or incorrect detection of data transport blocks (TBs) or code block groups (CBGs) in PDSCH, scheduling request (SR) indicating whether there is data to the UE in the UE's buffer, and CSI report to enable the gNB to select appropriate parameters for PDSCH or PDCCH transmission to the UE.

[0092] The CSI report from the UE can include a channel quality indicator (CQI) informing the gNB of a maximum modulation and coding scheme (MCS) for the UE to detect a TB at a predetermined block error rate (BLER), such as a BLER of 10%, a precoding matrix indicator (PMI) informing the gNB how to combine signals from multiple transmitter antennas according to multiple-input multiple-output (MIMO) transmission principles, a CSI-RS resource indicator (CRI) indicating a CSI-RS resource associated with the CSI report, and a rank indicator (RI) indicating a transmission rank for PDSCH.

[0093] The UL RS can include DM-RS and SRS. Typically, the DM-RS can be transmitted only within the BW of the respective PUSCH or PUCCH transmission. The gNB can use the DM-RS to demodulate information in the respective PUSCH or PUCCH. The UE can transmit the SRS to provide UL CSI to the gNB, and for TDD systems, the SRS transmission can also provide a PMI for DL transmission. In addition, to establish synchronization or initial higher layer connection with the gNB, the UE can transmit a physical random access channel (PRACH).

[0094] Figure 4B An example embodiment of an UL slot structure 410 for PUSCH transmission or PUSCH transmission is depicted in accordance with the subject matter disclosed herein. Figure 4B The embodiment of the UL slot structure 410 depicted in FIG. 4 is for illustration only. Figure 4BThe scope of the subject matter disclosed herein is not limited to any particular implementation. It should be noted that in the UL slot structure 410 as described below, UCI information does not need to be positioned as Figure 4B shown and can be positioned elsewhere as appropriate.

[0095] As Figure 4B shown, a slot 411 can include symbols 412 in which a UE transmits, for example, data information, UCI, or DM-RS. A UL system BW can include N RBs. Each RB can include symbols 412 in which a UE transmits, for example, data information, UCI, or DM-RS. A UL system BW can include N RBs. Each RB can include PUXCH M symbols 412 in which a UE transmits, for example, data information, UCI, or DM-RS. A UL system BW can include N RBs. Each RB can include

[0096] Figure 5A A block diagram depicting an example embodiment of a transmitter structure 501 using OFDM in accordance with the subject matter disclosed herein. Figure 5A The embodiment of the transmitter structure 501 depicted in FIG. 5 is for illustration only and other embodiments can have the same or similar configurations. Figure 5A The scope of the subject matter disclosed herein is not limited to any particular implementation.

[0097] As Figure 5A shown, information bits, such as DCI bits or data information bits 502, can be encoded by an encoder module 503, rate matched to allocated time / frequency resources by a rate matcher module 504, and modulated by a modulator module 505. Subsequently, a SC mapping module 507, controlled by a transmission bandwidth module 508, can map the modulated coded symbols and a DM-RS or CSI-RS module 506 to SCs. An inverse fast Fourier transform (IFFT) can be performed by a filter module 509. A cyclic prefix (CP) can be added to the output of the filter module 509. The resulting signal can be filtered by a common interface unit (CIU) filter module 510 and transmitted as a transmit signal 512 by an RF module 511.

[0098] Figure 5B A block diagram depicting an example embodiment of an OFDM receiver structure 531 in accordance with the subject matter disclosed herein. Figure 5B The embodiment of the receiver structure 531 depicted in FIG. 6 is for illustration only and other embodiments can have the same or similar configurations. Figure 5B The scope of the subject matter disclosed herein is not limited to any particular implementation. AsFigure 5B As shown, the received signal 532 can be filtered by filter module 533. A CP removal module 534 can remove the cyclic prefix. A filter module 535 can apply a fast Fourier transform (FFT). An SC demapping module 536 can demap the SC selected by BW selector module 537. The received symbols can be demodulated by channel estimator and demodulator module 538. A rate de-matcher module 539 can recover rate matching, and a decoder module 540 can decode the resulting bits to provide data information bits 541. DL transmissions and UL transmissions can be based on an orthogonal frequency division multiplexing (OFDM) waveform, including a variant using a DFT prefix known as DFT-spread-OFDM.

[0099] As previously mentioned, the goal of the 3GPP Rel-17 SID on RedCap NR devices is to support the same set of use cases in FR2 as in FR1. Beam optimization can be a key feature for FR2 operation in NR. One important issue involves enabling beam optimization procedures for RedCap UEs in RRC_INACTIVE state (also referred to herein as RRC inactive state or inactive mode). Accordingly, the subject matter disclosed herein provides a set of beam optimization procedures to enable RedCap in inactive mode transmissions in FR2.

[0100] HST-SFN transmission is a type of coherent joint transmission that uses only one physical downlink control channel (PDCCH) to allocate one set of physical downlink shared channel (PDSCH) resources. The same PDSCH is transmitted from multiple TRPs simultaneously. Figure 6 An example HST-SFN environment 600 is depicted in which coherent joint transmission can occur. In the example environment 600, a UE 601 can be traveling on a high-speed train 602. The UE 601 can be in communication with a first TRP 1 and a second TRP 2. Figure 6 In the example environment 600, the UE 601 can receive a first PDSCH1 from the first TRP 1 and a second PDSCH1 from the second TRP 2.

[0101] From the UE perspective, the additional downlink transmission from TRP 2 can be interpreted as an additional downlink delay spread component originating from a single TRP. Since in fact each TRP can use an independent local oscillator, and the UE mobility with respect to each TRP can be different from the mobility of another UE, there can be differences in the frequency offset at the UE. That is, a UE moving away from the first TRP 1 and towards the second TRP 2 can experience a negative Doppler shift moving away from the first TRP 1 and a positive Doppler shift moving towards the second TRP 2. In SFN manner of transmission, both TRPs transmit the same TRS and DMRS, and as a result, the UE can perform estimation on the composite propagation channel. In general, coherent joint transmission can be considered less practical since it involves ideal transmission connectivity and thorough synchronization, as well as precise channel state information, in order to ensure that the downlink transmissions add up favorably at the UE.

[0102] TRP-specific TRS transmission

[0103] In SFN transmission, one important factor to consider is the dynamic switching capability between TRPs. In SFN manner of transmission, this can involve additional SFN TRS / CSI-RS resources dedicated for SFN transmission to derive QCL properties. As used herein, quasi co-located means that two antenna ports are called quasi co-located if the properties of the channel over which a symbol on one antenna port is transmitted can be inferred from the channel over which a symbol on another antenna port is transmitted. Figure 7 An example RS overhead on an example bandwidth is shown for the configuration of QCL reference RS in SFN transmission of three TRPs. Figure 7 The horizontal axis in is time t, and the vertical axis is frequency band f. Figure 7 A total of seven TRSs are used in, with three TRSs for TRP A, TRP B, TRP C, and the other four TRSs for scenarios including TRP A+TRP B, TRP B+TRP C, TRP A+TRP C, and TRP A+TRP B+TRP C.

[0104] For multiple QCL reference RSs for the same DMRS port(s) (where each QCL reference RS corresponds to a specific TRP (TRP-specific)), there is no need to configure additional TRS / CSI-RS resources dedicated for SFN transmission for the UE. This can reduce the RS overhead for configuring QCL reference RSs.

[0105] Figure 8 An individual QCL RS for three TRPs (i.e., TRP A, TRP B, and TRP C) sufficient for dynamic switching among TRP A, TRP B, TRP C is shown. Figure 8The horizontal axis is time t and the vertical axis is frequency band f. Each TRP has an independent QCL reference RS, which is frequency division modulated (FDMed) to the RS of other TRPs. Based on this, Figure 8 The three TRSs shown can be used not only for the dynamic switching case of TRP A, TRP B, TRP C, but also for the cases of TRP A + TRP B, TRP B + TRP C, TRP A + TRP C, and TRP A + TRP B + TRP C, since each TRS has an independent QCL assumption. For example, if TRP A is used for PDSCH, the PDSCH DMRS can be dynamically indicated to be quasi co-located with the TRS from TRP A. If TRP A + TRP B is used for PDSCH, the PDSCH DMRS can be dynamically indicated to be quasi co-located with both the TRS from TRP A and the TRS from TRP B.

[0106] Furthermore, the TRS and the corresponding DMRS port(s) in SFN transmission can experience a composite channel representing the dominant path of each TRP. To perform DMRS channel estimation, the UE first estimates large scale profiles such as Doppler shift, Doppler spread, average delay, and delay spread. Using a single QCL reference RS, i.e., if the TRS and the DMRS are quasi co-located with a single transmission configuration indicator (TCI) state containing the composite channel of the TRPs, the UE can need very high complexity in order to be able to estimate significantly different Doppler shifts accurately based on the composite TRS. Such a complex UE can then use a Wiener filter on the estimated Doppler shifts to improve channel estimation performance. For multiple QCL reference RSs of the same DMRS port(s), where each QCL reference RS corresponds to a specific TRP (TRP-specific), the UE does not need to estimate and track multiple Doppler shifts from a single composite TRS. As a result, the complexity of the UE can be significantly reduced.

[0107] Figures 9A-9C Three dynamic switching scenarios in an example HST-SFN environment 900 including a first TRP 1, a second TRP 2, and a UE are depicted, respectively. Figure 9A A dynamic switching scenario when PDSCH is transmitted from TRP 1 is depicted. Figure 9B A dynamic switching scenario when PDSCH is transmitted from TRP 2 is depicted. Figure 9C A dynamic switching scenario when PDSCH is transmitted from both TRP 1 and TRP 2 is depicted. Using TRS transmission with TRP-specific (i.e., multiple QCL assumptions), a total of two TRS resources (each with a separate QCL assumption) is sufficient for Figures 9A-9C Dynamic switching of the three scenarios depicted in FIG. 9A.

[0108] With TRP-specific TRS transmission, a low-complexity UE can accurately estimate two different Doppler shifts based on two received TRSs with separate QCL assumptions. To improve the throughput, the UE can still perform per-tap Doppler shift channel estimation. That is, the estimated per-tap frequency offset can be used to compute the channel coefficients, and then tap-dependent time-domain channel interpolation can be performed.

[0109] In the following description, the functionality of the TRPs described in various HST-FSN scenarios and methods can be provided by the example base stations depicted in Figure 2 , and the functionality of the UEs described in various HST-FSN scenarios and methods can be provided by the example UEs depicted in Figure 3 .

[0110] Pre-compensation with TRP-specific TRS transmission

[0111] The first embodiment disclosed herein provides a coordination of network and UE for pre-compensation of frequency offset, which can be used to reduce the complexity of the UE. That is, the network can pre-compensate different frequency offsets for the UE for estimating different Doppler shifts. To this end, the UE can explicitly report the estimated Doppler shifts using the CSI framework. Alternatively, the UE can implicitly (implicit UE indication) allow each TRP to estimate the Doppler shift based on the UL signal transmitted by the UE.

[0112] The Doppler shift pre-compensation can be provided by the network using a reference TRP, where the reference TRP is used for pre-compensation of different Doppler shifts for both explicit reporting and implicit UE indication. The reference TRP can be pre-configured or semi-statically indicated to the UE. In a first aspect of the first embodiment, the specific (predetermined) TRP can be the TRP that transmits the PDSCH in the dynamic switching between TRPs, as shown in Figures 10A-10C for the three dynamic switching scenarios of Figures 9A-9C . Alternatively, a second aspect of the first embodiment can use a non-predetermined TRP for pre-compensation of different Doppler shifts. As shown in Figures 11A-11C(1) for the three dynamic switching scenarios of Figures 9A-9C , the non-predetermined TRP that transmits the PDSCH can become the reference TRP for the UE.

[0113] For the first aspect of the first embodiment shown in Figures 10A-10C , for all dynamic switching transmission cases, the predetermined TRP (e.g., TRP 1) known to the UE (e.g., can be indicated by a specific TCI state) is always the reference for the frequency offset pre-compensation on the gNB side.

[0114] In Figures 10A-10CIn each of these, TRP 1 is a predefined reference TRP. Figure 10A In this process, TRP 1 sends a TRS to the UE. Figure 10B In the process, TRP 2 sends a TRS to the UE. Figure 10C In this process, both TRP 1 and TRP 2 send TRS to the UE.

[0115] The UE experiences a Doppler frequency shift Δf1 relative to TRP 1 and a Doppler frequency shift Δf2 relative to TRP 2. Based on the TRS received from the reference TRP, the UE determines f. UE =f c +Δf, and send transmission f to both TRP 1 and TRP 2. UE UL RS(UL RS(f) c +Δf). In response, TRP 1 determines f. TRP1 =f UE +Δf1=f c +Δf+Δf1, and in f c Send DL. TRP 2 determines f TRP2 =f UE +Δf2=f c +Δf+Δf2 and Δf pre2 =f TRP1 -f TRP2 =Δf1-Δf2, and send the transmission f c +Δf pre2 The DL received from TRP 1. In response to the DL received from TRP 1, the UE's carrier frequency changes to f. UE =f c +Δf1.

[0116] for Figures 11A-11C(1) In a second aspect of the first embodiment depicted in 1C, the TRP for transmitting the PDSCH in each of the three dynamic handover scenarios can be a reference TRP for frequency offset compensation provided on the network side. Note that for Figure 11C(1) and 11C(2) In the case where both TRP 1 and TRP 2 send PDSCH, either TRP can be considered as the reference TRP. Figure 11C(1) depicts the case when TRP 1 is the reference TRP. Figure 11C(2) depicts the case when TRP 2 is the reference TRP.

[0117] When processing Figures 11A-11C(1) During the dynamic switching between the situations shown in 1C, the carrier frequency f of the received signal... cmay be considered for the same DMRS port and the UE can be activated with a TCI codepoint with up to two TCI states. Therefore, in the case that one TCI state is assigned per TRP, the UE can determine which transmission dynamic is being used accordingly and resolve the specific Doppler shift for channel estimation as long as the QCL source of the Doppler shift is indicated in the DCI appropriately. However, in the case of Figures 10A-10C The frequency offset pre-compensation shown in FIG. 1C, the carrier frequency f c The frequency offset pre-compensation shown in FIG. 1C, the carrier frequency f Figures 9A-9C remains the same in the dynamic switching cases. Moreover, because the network should pre-configure or semi-statically indicate the reference TRP to the UE, the signaling overhead for Figures 11A-11C(1) The signaling overhead for the frequency offset pre-compensation shown in FIG. 1C can be less than the signaling overhead for Figures 10A-10C 1C. Based on the lower signaling overhead, Figures 11A-11C(1) The embodiments depicted in FIG. 1C, where a predetermined TRP can be considered as the reference TRP for the frequency offset compensation at the gNB side, can tend to be superior to the method of Figures 12A-12C 1C.

[0118] In a third aspect of the first embodiment, the network can provide pre-compensation for different frequency offsets per TRP without assigning a reference TRP. Each TRP can be responsible for the pre-compensation of the frequency offset corresponding to the path between that TRP and the UE. Figures 13-11C(1) The frequency offset compensation schemes for the three dynamic switching cases are shown, respectively, where each TRP is responsible for its own corresponding frequency offset pre-compensation. It should be noted that similar to the embodiments of Figure 13 The carrier frequency f c remains the same in the dynamic switching.

[0119] In the current specification for NZP-CSI-RS-ResourceSet configured with the higher layer parameter trs-Info, the UE shall assume that the antenna port is the same as the same port index of the NZP CSI-RS resource configured in the NZP-CSI-RS-ResourceSet. Therefore, all different TRS resources in the set can be represented as one resource.

[0120] The subject matter disclosed herein provides for TRP-specific TRS reference signals that can be transmitted from two TRPs configured as one set, as this aspect applies to the combination of Figure 13 FIGS. 11A-11C, and Figure 13All the scenarios described, because the QCL information of NZP CSI-RS is configured at the resource level, this can reduce the overhead of TRS set configuration. It should be noted that only when the resources have the same TCI state, the antenna ports with the same port index of the TRS resources configured in the set can be the same.

[0121] As shown below, in the resource mapping in 3GPP specification 38.331, each NZP-CSI-Resource can be configured with a frequency domain allocation bit string. Among all the possible mappings, only row 1 can be used for TRS reference signals, because row 1 has a high density of three REs per RB, which provides the measurement accuracy of tracking time and frequency offset. The four-bit string of row 1 can have only a single bit set to "1", which can be used to indicate the first RE in the frequency domain allocation.

[0122] CSI-RS-ResourceMapping information element

[0123]

[0124] A TRS resource set can be configured such that the CSI-RS-ResourceMapping of the TRS reference signals (i.e., NZP CSI-RS resources) transmitted from two TRPs use different bit strings to have non-overlapping frequency domain RE allocations. The TRS transmissions from the two TRPs can be simultaneous (i.e., have the same firstOFDMSymbolInTimeDomain configuration) or have the same symbol offset (i.e., have different firstOFDMSymbolInTimeDomain configurations). It should be noted that for aperiodic TRS reference signals, the transmissions from the two TRPs are in the same slot, because the aperiodicTriggeringOffset parameter is configured per set, not each resource individually. The aperiodicTriggeringOffset parameter indicates the time offset between the slot in which the UE receives the aperiodic trigger and the slot during which the resource set is transmitted.

[0125] The performance in HST scenarios can be particularly sensitive to the Doppler measurement error based on high mobility and corresponding high Doppler shift. To accurately estimate the Doppler shift near the TRP, a frequent TRS transmission rate can be used. However, in areas relatively far from the TRP, a lower TRS rate can be sufficient. Therefore, the MAC CE can dynamically update the TRS transmission period for HST deployment scenarios to avoid the RRC reconfiguration overhead.

[0126] Similarly, the accuracy of the Doppler shift estimation at the gNB can be impacted by the UL RS transmission rate when the network pre-compensates for the frequency offset. Frequent sounding reference signal (SRS) transmission rate can be used near the TRP, while a lower SRS transmission rate can be sufficient in areas relatively far from the TRP. MAC CE can be used to dynamically update the UL RS transmission periodicity for HST deployment scenarios.

[0127] Network frequency offset pre-compensation with explicit UE reporting

[0128] One embodiment of network frequency offset pre-compensation provides explicit UE reporting. For this embodiment, the UE can explicitly report the different Doppler shifts measured for each TRP as part of the CSI reporting to the gNB. With TRS / CSI RS transmission in TPR fashion, large-scale profile measurements, including Doppler shift and Doppler spread, can be performed independently for each TRP. However, it should be noted that this additional reporting of Doppler shift can increase the reporting overhead and can also include UE estimation error and / or feedback latency.

[0129] The current specification framework for CSI reporting triggering and transmission can be used for explicit UE reporting. One approach can be to let the network calculate the Doppler shift with the channel measurement variables. Another solution can be to introduce a new reporting quantity for Doppler shift in CSI-ReportConfig. Note that TRS is a set of CSI-ReferenceSignal resources with specific configuration to maximize the tracking performance. The trs-info flag in the NZP-CSI-RS-ResourceSet parameter structure indicates that the CSI-RS resource set is being used as TRS. One example of specification modification to address explicit UE reporting of the Doppler shift(s) per TRP (trs-doppler-shift) can be as follows.

[0130] CSI-ReportConfig information element

[0131]

[0132] Since the current specification explicitly prohibits the inclusion of TRS in CSI reporting, the introduction of a new reporting quantity for Doppler shift in CSI-ReportConfig can involve removing such a restriction. That is, a UE can be configured with a CSI-ReportConfig linked to a CSI-ResourceConfig, where the CSI-ResourceConfig contains a NZP-CSI-RS-ResourceSet configured with trs-Info. In addition, the UE can be configured with a CSI-ReportConfig, where for a NZP CSI-RS resource set configured with trs-Info, the higher layer parameter reportQuantity is set to non-“none”.

[0133] Network frequency offset pre-compensation with implicit UE indication

[0134] Another embodiment of network frequency offset pre-compensation provides implicit UE indication. Note that the TRS transmission in these schemes is TRP-specific (i.e., as Figure 14 5 shows TRS TRP ).

[0135] Figure 13 A fourth aspect of a first embodiment of network frequency offset pre-compensation according to the subject matter disclosed herein is depicted, where the network frequency offset pre-compensation uses a three-step procedure with implicit UE indication. The procedure starts with TRS transmission at 1301. A set of TRSs, which are TRP-specific (i.e., with independent QCL assumptions), can be transmitted from two TRPs 1 and 2. The UE estimates the carrier frequency and two Doppler shifts based on the received set of TRSs. At 1302, the UE transmits uplink reference signals (e.g., SRS) to the two TRPs modulated with the carrier frequency estimated based on the received set of TRSs. At 1303, the network estimates the frequency offset difference of the UL RS (i.e., SRS) received at the two TRPs and pre-compensates the frequency offset difference Δf pre .

[0136] Figure 13The initial TRS transmission set at 1301 can be transmitted for the purpose of frequency offset estimation at the UE. At 1302, it can also be used for the purpose of QCL RS for UL RS (e.g., SRS) transmission. For this aspect of the first embodiment, the TRS transmission can occur only once as an aperiodic transmission and can not be used for every DMRS and PDSCH transmission. Moreover, in the current specification, the UE can not have the obligation to use TRS for carrier frequency estimation and the UE can use any other DL RS to maintain the frequency loop. That is, the main procedure of network pre-compensation for different Doppler shifts of downlink transmission can include Figure 14 periodic transmission of UL RS (at 1302) and TRS (at 1303).

[0137] Figure 13 depicts a fifth aspect of the first embodiment of network frequency offset pre-compensation according to the subject matter disclosed herein, where the network frequency offset pre-compensation uses a two-step procedure starting with UL RS transmission. The two-step procedure is similar to Figure 14 1302 and 1303 in

[0138] It should be noted that the frequency offset difference at the gNB for downlink transmission (i.e., Δf pre ) pre-compensation can be used for Figure 13 the fourth aspect of the first embodiment shown in Figure 14 the fifth aspect of the first embodiment shown in

[0139] In the fourth and fifth aspects of the first embodiment, the TRS overhead for dynamic switching transmission can be reduced. However, the conventional QCL rule for delay-related large-scale profile can not hold because TRS can be transmitted in a TRP-specific manner while DMRS and PDSCH can be transmitted in an SFN manner. To address this issue, it can be noted that a Rel-17 UE can be activated using a TCI codepoint with two TCI states. In the current specification, two activated TCI states correspond to different DMRS ports. In this context, the UE can associate the PDSCH DMRS port(s) with two TCIs simultaneously (i.e., one TCI state per TRP). That is, the same DMRS port(s) can consider multiple QCL assumptions. The DMRS antenna port(s) associated with each TRP can be configured to be quasi co-located with the TRS transmitted from that TRP.

[0140] For large-scale profiles related to Doppler shift, if the frequency offset is pre-compensated by TRS and DMRS and PDSCH (i.e., the fourth aspect), the QCL rule or UE-side frequency offset tracking based on the received TRS will not have any problem. The Doppler shift information does not violate the QCL rule because the QCL RS of DMRS and PDSCH is the TRS on the second TRS transmission. In addition, for the second TRS transmission after the pre-compensation of the frequency offset, it will not have any problem for the UE to estimate and compensate the frequency offset of DMRS and PDSCH according to the received TRS.

[0141] If the frequency offset is not pre-compensated for TRS but for DMRS and PDSCH (i.e., the fifth aspect), the DMRS and PDSCH transmission from the non-reference TRP violates the QCL rule of Doppler shift. The UE can estimate and pre-compensate the frequency offset based on the received TRS. Instead of pre-compensating the frequency offset of TRS, the UE can estimate the frequency offset based on TRS and can apply the estimation to the received DMRS and PDSCH that have been compensated by the network. To solve the QCL rule violation problem in the first embodiment, a new QCL type can be used for the TRS transmitted from the non-reference TRP that only includes delay-related large-scale profiles (i.e., delay spread and average delay). That is, the QCL RS for PDSCH DMRS can be the TRS transmitted from the reference TRP with QCL Type B, and the second TRS transmission from the non-reference TRP can only be used to extract the delay spread and average delay information of the path from the non-reference TRP to the UE. In addition, to solve the frequency offset tracking problem based on the UE-side TRS, if the TRS transmission is TRP-specific, the gNB can indicate to the UE to track the frequency offset based only on the TRS received from the reference TRP (e.g., pre-configured or indicated semi-statically with a specific TCI state). In the fourth and fifth aspects of the first embodiment depicted in Figure 15A and Figure 15B In the fourth and fifth aspects of the first embodiment depicted in Figure 15A and Figure 16A The methods and explanations of

[0142] Figure 16B and Figure 16AExample embodiments of a three-step procedure and a two-step procedure for network frequency offset pre-compensation according to the subject matter disclosed herein are depicted, respectively, where the network frequency offset pre-compensation provides TRP-specific frequency offset pre-compensation independently for each TRP. However, it should be noted that for the case of pre-compensating the frequency offset for all downlink transmissions (i.e., TRS, DMRS, and PDSCH), only the three-step procedure embodiment of Figure 16B may be considered. In the two-step procedure, the uncompensated TRS can not be considered as a QCL RS for the PDSCH DMRS due to the violation of the QCL rule, while the channel estimation still involves the QCL RS of the PDSCH DMRS to extract the Doppler shift related large-scale profile.

[0143] SFN manner TRS transmission

[0144] SFN manner TRS transmission can involve high complexity UE to accurately estimate significantly different Doppler shifts based on the combined TRS. If the network pre-compensates the different Doppler shifts from the two TRPs, the channel estimation and PDSCH demodulation can not require the high complexity UE.

[0145] In the embodiments disclosed herein that use the three-step or two-step procedure, with TRP-specific TRS transmission for network frequency offset pre-compensation, the value of the estimated carrier frequency at the UE can not need to be accurate since the estimated carrier frequency is only used for the uplink RS transmission to the two TRPs and the network can pre-compensate the Doppler shift difference of the two TRPs.

[0146] A second embodiment disclosed herein involves UE and network cooperation with SFN manner TRS transmission (i.e., TRS SFN ) with network frequency offset pre-compensation. It can be noted that using SFN manner TRS transmission with network frequency offset pre-compensation can reduce the complexity of the UE while being backward compatible to the legacy HST-SFN deployment scenario, however, it can still involve high TRS overhead.

[0147] Network frequency offset pre-compensation with implicit UE indication

[0148] Figure 16A and Figure 16A Second embodiments of a three-step procedure and a two-step procedure for network frequency offset pre-compensation according to the subject matter disclosed herein are depicted, respectively, where the network frequency offset pre-compensation uses SFN manner TRS transmission with implicit UE indication. In Figure 16BIn the illustrated embodiment, at 1601, a set of TRSs can be transmitted from two TRPs. At 1602, the UE transmits uplink reference signals to both TRPs. At 1603, the network estimates the frequency offset difference at both TRPs and pre-compensates the downlink transmission for the non-reference TRP for the Doppler shift difference. For this embodiment, the TRS transmissions at 1601 and 1603 can be based on SFN approach. Figure 16A The depicted embodiment in Figure 16A is similar to the embodiment of Figure 16B but starts at 1602 since the first step at 1601 is not used for the two-step procedure. It can be noted that only the embodiment of Figure 16A involves frequency offsets that can be pre-compensated for TRS as well as DMRS and PDSCH since the channel estimation involves a QCL source for PDSCH DMRS for the Doppler shift and in the embodiment of since the QCL rule violation, SFN approach TRS can not be a QCL RS unless additional resources are provided for this QCL rule violation, which can not be practical.

[0149] Figure 16B For SFN approach TRS transmission in , the UE estimates the UL carrier frequency for the SRS transmission based on the received composite TRS. A high-complexity UE can track multiple Doppler shifts from a single composite TRS and the UE at 1602 can likely estimate an incorrect frequency offset. However, the value of the estimated carrier frequency at the UE does not involve any significant operational error since the estimated carrier frequency is only used for the uplink RS transmission to both TRPs so that the network can estimate and compensate for the frequency offset difference of the two TRPs.

[0150] Figure 17A For delay-dependent large-scale profiles for the embodiments using Figure 17B and , considering that the QCL RS for DMRS and PDSCH is the second TRS transmission (where both the TRS and the corresponding DMRS port(s) experience a composite channel considering the dominant path for each TRP), there is no QCL rule violation. However, the SFN approach transmission can involve high TRS overhead in order to derive the QCL characteristics for dynamic switching between the TRPs.

[0151] Figure 16A In the embodiments of Figure 16B , for Doppler shift-dependent large-scale profiles, the frequency offset is always compensated for TRS as well as DMRS and PDSCH, so there will be no issues for the QCL rule regarding Doppler shift information and for UE-side frequency offset tracking and compensation based on the received TRS.

[0152] Figure 17A and Figure 17BExample embodiments of a three-step and two-step procedure according to the subject matter disclosed herein are depicted, respectively, that use SFN manner TRS transmissions, where network pre-compensation is provided independently for each TRP. For Figure 18 and Figure 9A provided explanations apply to embodiments of Figure 18 and Figure 19 .

[0153] As shown in Figure 18 , another aspect of the second embodiment combines SFN and TRP-specific TRS transmissions for a three-step procedure. At 1801, TRS transmissions are made in SFN manner. At 1802, the UE transmits UL RS. At 1803, a TRP-specific second TRS transmission is transmitted. The TRP-specific transmission provides independent delay spread information estimation and TRS overhead reduction for dynamic switching. Further, similar to the TRP-specific TRS transmission, the frequency offset difference pre-compensation at the gNB for downlink transmission can be used for all TRS, DMRS, and PDSCH, or only for DMRS and PDSCH without TRS transmission.

[0154] The second set of TRS can be considered as QCL RS for DMRS and PDSCH. For TRP-specific TRS, the conventional QCL rule for delay-related large-scale profile can not hold, as TRS is transmitted in TRP-specific manner while DMRS and PDSCH are transmitted in SFN manner. To address this, it is noted that a Rel-17 UE can activate with a TCI codepoint with two TCIs. In current specification, two activated TCI states correspond to different DMRS ports. Here, the approach is that the UE can associate the PDSCH DMRS port(s) with two TCIs simultaneously (i.e., one TCI state per TRP). That is, multiple QCL assumptions can be considered for the same DMRS port. The DMRS antenna port associated with each TRP can be configured to be quasi co-located with the TRS transmitted from that TRP.

[0155] In the dynamic switching scenario of Figure 19 , for using Figure 19The large-scale profile related to Doppler shift of the method of the first embodiment does not have any problem for the QCL rule on Doppler shift information and UE-side frequency offset tracking and compensation based on the received TRS. However, the QCL RS of the PDSCH DMRS is the second TRS transmitted from the reference TRP with QCL Type B, and a new QCL Type can be introduced for the TRS of the non-reference TRP, which only contains the delay-related large-scale profile. In addition, the gNB should indicate to the UE that only the TRS of the reference TRP can be considered as the QCL RS for the Doppler shift-related large-scale profile.

[0156] Figure 20 Another aspect is shown according to a second embodiment of the subject matter disclosed herein, which combines SFN and TRP-specific TRS transmission with network pre-compensation of Doppler shift independently provided for each TRP. Figure 20 The explanations of the aspects of the second embodiment depicted in Figure 20 The aspects of the second embodiment depicted in Figure 21 The aspects depicted in can only be considered for the case of pre-compensating frequency offset for all downlink transmissions (i.e., TRS, DMRS, and PDSCH) based on QCL rule violation issues.

[0157] Table 1 sets out a summary of some features and characteristics associated with the first and second embodiments.

[0158] Table 1.

[0159]

[0160]

[0161] QCL assumption of TRS as target RS

[0162] QCL relationship information can assist the UE in channel estimation, frequency offset estimation, and synchronization procedures. The QCL relationship of TRS reference signals can be configured per resource by NZP-CSI-RS-Resource for periodic resources, as shown below. For semi-persistent resources, the QCL relationship of TRS reference signals can be configured by a medium access control (MAC) control element (CE) triggering procedure, as shown below. For aperiodic resources, the QCL relationship of TRS reference signals can be configured by a DCI triggering procedure for aperiodic resources, as shown below. Figure 22

[0163] a) Periodic

[0164] NZP-CSI-RS-Resource information element

[0165] ​

[0166] b) Non-periodic

[0167] CSI-AperiodicTriggerStateList Information Element

[0168]

[0169] For semi-persistent CSI-RS resource sets activated / deactivated by MAC CE ( Figure 22 The MAC CE structure indicates that the index of the NZP-CSI-RS-ResourceSet contains semi-persistent NZP CSI-RS resources and TCI-StateIds that can be used as QCL sources for resources in the indicated resource set. For non-periodic CSI-RS, the CSI request field in DCI format 0_1 ​​can occupy up to 6 bits (determined by the high-level parameter reportTriggerSize in CSI-MeasConfig), selecting one from all trigger states. TCI state and QCL information can be configured for each nzp-CSI-RS in CSI-AssociatedReportConfigInfo.

[0170] Large-scale radio channel characteristics (such as Doppler shift, Doppler spread, average delay, and delay spread) can be shared across different antenna ports. QCL type relationships can be introduced to support channel estimation, frequency offset estimation, and synchronization processes when the UE receives the PDCCH and PDSCH. In the current specification, four different types of QCL relationships are defined to indicate the large-scale channel characteristics across a set of QCL antenna ports, as follows:

[0171] QCL Type A: {Doppler frequency shift, Doppler spread, average delay, delay spread}

[0172] QCL type B: {Doppler frequency shift, Doppler spread}

[0173] QCL type C: {Doppler frequency shift, average delay}, and

[0174] QCL type D: {space receiver parameters}.

[0175] For all embodiments disclosed herein, the QCL reference signal for the first step of TRS transmission (applicable for three-step procedure) can be a specific synchronization signal / physical broadcast channel (SS / PBCH) block or any other CSI reference signal with QCL Type A that covers large-scale profiles for delay and Doppler shift related. The QCL Type D reference signal for the first step of TRS transmission can be used as the corresponding TRP-specific SS / PBCH block.

[0176] However, the case of TCI state and QCL information configuration can be different for the second TRS transmission (in the third step of three-step procedure or in the second step of two-step procedure). Depending on the fact that the network pre-compensates frequency offset for all TRS, DMRS and PDSCH or the network pre-compensates frequency offset only for DMRS and PDSCH but not for TRS, the QCL reference signal for the second transmitted TRS can be defined differently. In both types of cases (three-step or two-step procedure), the QCL Type D reference signal for the second TRS transmission can be the corresponding TRP-specific SS / PBCH block or the first TRS transmitted from the corresponding TRP.

[0177] With three-step procedure, the QCL RS for the second TRS transmitted from the reference TRP can be the first TRS transmitted from the reference TRP. Alternatively, the QCL RS for the first TRS transmitted from the reference TRP with QCL Type A (i.e., all Doppler shift, Doppler spread, mean delay and delay spread information) can be the first TRS transmitted from the reference TRP. Moreover, for delay related large-scale profile, the QCL RS for the second TRS transmitted from the non-reference TRP can be the first TRS transmitted from this TRP or the QCL RS for the first TRS transmitted from this TRP with a new QCL Type definition that only includes mean delay and delay spread information. For Doppler shift related large-scale profile, the QCL RS for the second TRS transmitted from the non-reference TRP can be the first / second TRS transmitted from the reference TRP or the QCL RS for the first / second TRS transmitted from the reference TRP with QCL Type B.

[0178] Since there can be no TRS transmission in the first step of the two-step procedure, the QCL RS of the TRS transmitted from the reference TRP can be the specific SS / PBCH block or any other CSI reference signal with QCL Type A, while the QCL RS of the TRS transmitted from the non-reference TRP can be the specific SS / PBCH block or any other CSI reference signal with a new QCL Type for delay spread and average delay information as well as for Doppler shift and Doppler spread information. The QCL RS of the TRS can be the TRS transmitted from the reference TRP or the QCL RS of the TRS transmitted from the reference TRP with QCL Type B.

[0179] In the current specification, each TCI state contains the QCL relationship of one or two downlink reference signals with two different QCL Types. For the second TRS transmission from the non-reference TRP in the three-step procedure and the TRS transmission in the two-step procedure, two more different QCL Types can be used in addition to QCL Type D (i.e., a new QCL Type for delay-related large-scale profile and QCL Type B for Doppler shift-related large-scale profile). To address this issue, the specification can be modified so as to allow up to three different QCL Types as well as DL reference signal configurations in each TCI state.

[0180] With the three-step procedure, the QCL RS of the second TRS transmitted from each TRP can be the first TRS transmitted from that TRP or can be the QCL RS of the first TRS transmitted from that TRP with QCL Type A. With the two-step procedure, the QCL RS of the TRS transmitted from each TRP can be the specific SS / PBCH block or any other CSI reference signal with QCL Type A.

[0181] Furthermore, for the three-step network pre-compensation, two different cases can need to be considered. First, both TRS transmissions come from the same resource set, and second, two different TRS resource sets can be configured for the first and second TRS transmissions.

[0182] The first case involves the QCL information update for the second TRS transmission since the network pre-compensation of the frequency offset violates the previously configured QCL relationship information of the TRS resource. In this case, similar to the current MAC CE structure for activating / deactivating semi-persistent CSI-RS shown in Figure 23 The MAC CE can be used to update the QCL information of the TRS resources in the set. Alternatively, the network can only configure QCL Type D (a new QCL Type including only the delay-related large-scale profile information) as well as the corresponding reference signal in the TCI state of the TRS as the source RS. The QCL Type B RS of the TRS as the source RS can be the TRS itself.

[0183] Further, the first scenario assumption can be compatible with no further impact as the network does not pre-compensate the second TRS transmission. It can be noted that in this scenario, the QCL Type-D reference signal can be the corresponding TRP-specific SS / PBCH block.

[0184] For the second scenario assumption, the QCL RS of the second TRS transmitted from the reference TRP can be the QCL RS of the first TRS transmitted from this TRP or the first TRS transmitted from this TRP with QCL Type-A. The QCL RS of the second TRS transmitted from the non-reference TRP can be the QCL RS of the first TRS transmitted from this TRP or the first TRS transmitted from this TRP with QCL Type-A. However, for delay-related large-scale profiles, the QCL RS of the second TRS transmitted from the non-reference TRP can be the first TRS transmitted from this TRP. Alternatively, the QCL RS of the first TRS transmitted from this TRP can include a new QCL Type that includes only average delay and delay spread information. For Doppler shift-related large-scale profiles, the QCL RS of the second TRS transmitted from the non-reference TRP can be the first / second TRS transmitted from the reference TRP. Alternatively, the QCL RS of the first / second TRS can be transmitted from the reference TRP with QCL Type-B. Note that in the second scenario, the QCL Type-D reference signal can be the corresponding TRP-specific SS / PBCH block or can be the first TRS transmitted from the corresponding TRP.

[0185] With frequency offset pre-compensation TRS, the second TRS transmitted from the non-reference TRP should be configured with dynamic carrier frequency as the Doppler shift changes with time as the UE moves or changes speed. The frequency tracking mechanism at the UE can suffer from averaging / cumulative issues as different TRS transmission occasions will have different pre-compensation states. This issue can be addressed with dynamic QCL information update of the second TRS transmission. As mentioned earlier, the dynamic update can be used based on the fact that the network pre-compensation of the frequency offset violates the QCL relationship information of the previously configured TRS resources. With dynamic update of the QCL source RS, the TCI state change for pre-compensation TRS can provide an indication to the UE not to average / cumulate the TRS transmission occasions.

[0186] An alternative solution can be that the gNB can indicate to the UE to use only the transmitted TRS from the reference TRP for carrier frequency estimation to maintain the averaging / cumulative structure of the frequency loop. The reference TRP can be achieved by QCL indication in DCI scheduling PDSCH or pre-configuration / semi-static indication to the UE.

[0187] TRP-specific TRS and DMRS transmission

[0188] With TRP-specific TRS transmission, the UE can be able to estimate two significantly different large-scale profiles, especially based on the Doppler shifts of the two separate TRSs. However, for per-tap Doppler shift channel estimation, the UE can still include high complexity. That is, the estimated per-tap frequency offset can be used to compute the channel coefficients, and then tap-dependent time-domain channel interpolation can be performed to improve channel estimation performance and throughput. An alternative solution to improve DMRS channel estimation performance with less complex UEs can be that each TRP can use independent DMRS ports in PDSCH.

[0189] With TRP-specific TRS and DMRS transmission, the UE can estimate the propagation channel for each TRP orthogonally based on each DMRS antenna port mapped to each TRP. Then, the UE can reconstruct the composite SFN channel by combining the estimated channels from different TRPs. This can reduce the complexity of the UE channel estimation algorithm with improved performance. Therefore, network cooperation for frequency Doppler shift pre-compensation can no longer be used, and the UE can handle significantly different frequency offsets from two TRPs with low complexity.

[0190] Enhanced Rel-17 MAC-CE can activate two TCI states per TCI codepoint. This can enable the UE to associate DMRS with two TCIs simultaneously. To address this issue, one solution can be to use a comb-like TCI state allocation, where even comb REs can be allocated to a first TCI state and odd comb REs can be allocated to a second TCI state. For DMRS Type 1, this can mean that each TCI state can be allocated to one CDM group. Therefore, to summarize this solution, each CDM group can be allocated to one TCI state, at least for DMRS Type 1.

[0191] Another solution can be to allocate TCI states in a TD-OCC manner, where two orthogonal DMRS ports in one CDM group can be allocated to two different TCI states. All embodiments disclosed herein can allow the UE to use orthogonal channel estimation algorithms.

[0192] Rel-16 and Rel-17 scheme dynamic switching

[0193] For TRP-based pre-compensation, the same DMRS port(s) can be associated with up to two TCI states. This can be interpreted as an implicit indication / switching between the Rel-17 SFN-based frequency offset pre-compensation technique and single-TRP or Rel-15 SFN frequency offset pre-compensation technique. By reusing the Rel-17 enhanced TCI state activation / deactivation MAC CE structure, as shown in Figure 24 each codepoint of the TCI field in the DCI for UE-specific PDSCH can be mapped to up to two TCI states. With this structure, if Ci = 0 (i.e., the TCI codepoint in the DCI indicates a TCI state ID with only one mapped TCI state), the PDSCH transmission can be single-TRP, and if Ci = 1 (i.e., the TCI codepoint in the DCI indicates a TCI state ID with two mapped TCI states), the PDSCH transmission can be the Rel-17 SFN scheme.

[0194] Both the Rel-17 SFN scheme and the Rel-16 non-SFN scheme (i.e., SDM, FDM, and TDM schemes) can be beneficial for HST deployment scenarios. The Rel-17 SFN scheme can provide high reliability / coverage for cell edge or high-speed UEs, while the Rel-16 non-SFN scheme can provide high throughput for cell center or low-speed UEs. Therefore, the network should support dynamic switching / indication of scheduled PDSCH between the Rel-16 non-SFN and Rel-17 SFN schemes.

[0195] TRP-specific TRS transmission with pre-compensated frequency offset can involve two separate QCL types, one for delay-related large-scale profiles (i.e., new QCL type), and one for Doppler shift-related large-scale profiles other than QCL Type D (i.e., QCL Type B). This means that up to three different QCL types can be introduced in one TCI state to handle TRS transmission with pre-compensated frequency offset. This enhanced TCI state can be an indication of the Rel-17 SFN scheme. Based on the multiple different QCL types defined within the indicated TCI state, the UE can determine to transmit PDSCH in the Rel-17 SFN scheme or the Rel-16 non-SFN scheme.

[0196] PTRS enhancement and CPE compensation

[0197] In Rel-17, PDCCH and PDSCH in HST-SFN scenario can be transmitted in SFN manner with two TCI states. PDSCH transmission with two TCI states can involve two phase tracking reference signal (PTRS) ports (one for each TCI state) for accurate phase tracking at the UE, especially when different panels are used to receive PDSCH transmitted from different TRPs simultaneously.

[0198] The current specification supports two PTRS ports for SDM scheme in multi-TRP scenario, where two TCI states can be indicated by one TCI codepoint. The first PTRS port can be associated with the lowest indexed DMRS port among the DMRS ports corresponding to the first indicated TCI state, and the second PTRS port can be associated with the lowest indexed DMRS port among the DMRS ports corresponding to the second indicated TCI state. To extend the current specification for multi-TRP case in HST-SFN scenario, dual-port PTRS can be supported to provide accurate phase tracking at the UE, where each PTRS port corresponds to one TCI state.

[0199] In HST-SFN scenario, DMRS transmission can consider two scenarios, i.e., TRP-specific DMRS transmission (SFN TRP-specific) and SFN manner DMRS transmission (SFN manner). For both transmission types, support of dual-port PTRS can result in more accurate phase tracking at the UE.

[0200] In the current specification, the frequency density, time density, resource element offset, and Energy Per Resource Element (EPRE) ratio of PTRS are RRC configured by higher layer parameter PTRS-DownlinkConfig. With the dual-port PTRS method for HST-SFN downlink transmission, and following the current specification, these parameters can be RRC configured for each PTRS port. The number of PTRS ports can be RRC configured similarly to the PTRS configuration for uplink transmission in the current specification. With dynamic switching between the Rel-17 SFN scheme and single-TRP or Rel-15 SFN scheme, the maximum number of PTRS ports can be semi-statically configured, and the UE can ignore a specific PTRS port when handling uncorrelated PDSCHs. Alternatively, the number of PTRS ports can be dynamically updated / activated. This can be done by explicit RRC configuration for two PTRS ports for the Rel-17 SFN scheme, which can be activated by DCI. The TCI codepoint in the DCI can implicitly indicate the number of PTRS ports. With the enhanced TCI state activation / deactivation MAC CE structure, each codepoint of the TCI field in the DCI for UE-specific PDSCH can be mapped to up to two TCI states. With this structure, if Ci = 0 (i.e., the TCI codepoint in the DCI indicates a TCI state ID with only one mapped TCI state), the PDSCH transmission can be single-TRP with one port PTRS, and if Ci = 1 (i.e., the TCI codepoint in the DCI indicates a TCI state ID with two mapped TCI states), the PDSCH transmission can be the Rel-17 SFN scheme with two PTRS ports. Alternatively, the signaling of two PTRS ports can be done by MAC CE activation.

[0201] Dual-port PTRS in TRP-specific DMRS transmission

[0202] Channel estimation can be performed orthogonally for each TRP based on the corresponding DMRS antenna port of the TRP-specific DMRS transmission scheme, such that phase noise can be estimated and compensated orthogonally for each TRP with two PTRS port hypotheses (where each PTRS port corresponds to one TRP (i.e., TCI state)). The association of two TCI states and DMRS can be through comb allocation, where even comb REs can be allocated to the first TCI state (i.e., first TRP) and odd comb REs can be allocated to the second TCI state (i.e., second TRP). Alternatively, TD-OCC manner allocation can be used, where two orthogonal DMRS ports in one CDM group can be allocated to two different TCI states. In both scenarios, the first PTRS port can be associated with the lowest indexed DMRS port of the DMRS ports corresponding to the first TRP (i.e., first indicated TCI state), and the second PTRS port can be associated with the lowest indexed DMRS port of the DMRS ports corresponding to the second TRP (i.e., second indicated TCI state).

[0203] Two-port PTRS in SFN manner DMRS transmission

[0204] For SFN-mode DMRS transmission, the same RE can correspond to two different TCI states. That is, two TRPs can simultaneously use the same DMRS port, and the DMRS traverses a synthesized channel. In this case, considering two PTRS ports transmitted in SFN mode may not provide much benefit to the UE, as channel estimation may be based on the synthesized channel, and the same RE may be associated with two PTRS ports with two different indicated TCI states. To avoid two PTRS ports being associated with the same RE with two different TCI states, PTRS can be transmitted in a TRP-specific manner, while DMRS and PDSCH can be transmitted in SFN mode. In this case, the first PTRS port can be associated with the DMRS port with the lowest index among the DMRS ports corresponding to the first TRP (i.e., the first indicated TCI state), and the second PTRS port can be associated with the DMRS port with a predetermined / pre-configured index among the DMRS ports corresponding to the second TRP (i.e., the second indicated TCI state). The RE association information for the second PTRS port can be configured by RRC or dynamically indicated to the UE, or it can be the second lowest index DMRS port. The association between the two TCI states transmitted from the two TRSs and the PTRS can be comb-like or TD-OCC-like. This allows the UE to independently estimate the corresponding phase noise for each TRP. However, it should be noted that because the DMRS is transmitted in SFN mode and channel estimation can be based on a synthetic channel, individual phase tracking for each TRP can involve high complexity in the UE implementation. One possible UE implementation could be tap-based phase noise compensation, where the phase noise of each TRP can be estimated and compensated for for the corresponding channel taps. That is, due to the fact that channel modeling in an HST-SFN scenario may be based on the line-of-sight (LOS) propagation path of each TRP.

[0205] TRP from HST-SFN scene i The transmitted signal can be written in the time domain as:

[0206]

[0207] From TRP i The transmitted signal can be written in the frequency domain as:

[0208]

[0209] in It is TRP i The phase noise is denoted by S(k), and S(k) is the transmitted data on subcarrier k. Note that in the HST-SFN scenario, S(k) may be the same for two TRPs. Equation (2) can be summarized as follows:

[0210]

[0211] where is the common phase noise error (CPE) of the TRPs i and can be derived as:

[0212]

[0213] The second summation component in equations (2) and (3) is the ICI part due to channel variation within the OFDM symbol, which can be caused by the phase noise error. The received signal at the UE can be derived in the frequency domain as:

[0214]

[0215] where w(n) is the additive white Gaussian noise. If the ICI part is treated as additive noise and included within W(k), the received signal can be simplified and rewritten as:

[0216]

[0217] Figure 25 A block diagram illustrating an example embodiment of a UE receiver 2200 for demodulating and decoding received data is shown. The UE receiver 2200 can include a timing synchronization unit 2201, a CP-OFDM demodulation block 2202, a channel estimation block 2203, a phase noise estimation and compensation block 2204, a MIMO detection block 2205, and a decoding block 2206 connected as shown. The different functional blocks of the UE receiver 2200 can be provided by modules and / or circuits. The channel estimation block 2203 can estimate the channel based on the received DMRS, and since the DMRS can be transmitted in an SFN manner, the channel estimation can be based on the composite channel. That is, the estimated channel in the frequency domain is H est (k) = H1(k) + H2(k), where the received signal is equalized. However, as shown in equations (5) and (6), the phase noise compensation involves TRP-specific channel estimation. To address this issue, an implementation of the UE receiver can include a tap-based phase noise compensation technique.

[0218] The modeling of the propagation channel in the HST-SFN scenario can be based on the LOS propagation path of the TRPs. In the HST-SFN scenario with two TRPs, the channel can be represented by a two-tap model in the time domain, where each tap corresponds to the LOS path from one TRP. That is, the time-domain channel model is:

[0219]

[0220] where hi is the complex channel gain corresponding to the line-of-sight (LOS) propagation path from the TRP i is quantized to a tap delay in time-domain resolution, and T s is the symbol duration including CP. In other words, although the channel estimation block 2203 in Figure 26 estimates the composite channel, the channel structure in time-domain can be based on taps per TRP. The estimated channel per TRP (i.e., H i (k)) can be derived from the estimated composite channel (i.e., H est (k)).

[0221] This can be provided by an additional functional block to perform TRP-specific channel estimation by bringing the estimated channel H est (k) into time-domain, and then bringing back each tap of the time-domain channel (i.e., h i in equation (7)) into frequency-domain, respectively. This enables TRP-specific equalization for PTRS and TRP-specific CPE estimation at the UE. This more accurate phase tracking can achieve higher throughput at the cost of higher complexity.

[0222] Figure 27A An example block diagram of a UE receiver 2300 is shown in accordance with the subject matter disclosed herein. The UE receiver 2300 can include a timing synchronization unit 2301, a CP-OFDM demodulation block 2302, a channel estimation block 2303, a TRP-specific channel estimation block 2304, a phase noise estimation and compensation block 2305, a MIMO detection block 2306, and a decoding block 2307 connected as shown. The different functional blocks of the UE receiver 2300 can be provided by modules and / or circuits.

[0223] For FR2 applications (i.e., frequency bands from 24.25 GHz to 52.6 GHz), an example UE implementation can be that the UE will use two different panels to independently control the corresponding beams per TRP. That is, in an HST-SFN scenario, separate transmitter / receiver chains can be implemented for multi-TRP transmission.

[0224] Figure 27B ​​A block diagram illustrating an example embodiment of a UE receiver 2400 with separate receiver chains according to the subject matter disclosed herein is shown. The UE receiver 2400 can include a first receiver chain that can include a timing synchronization unit 2401, a CP-OFDM demodulation block 2402, a channel estimation block 2403, and a phase noise estimation and compensation block 2404 connected as shown, and a second receiver chain that can include a timing synchronization unit 2411, a CP-OFDM demodulation block 2212, a channel estimation block 2213, and a phase noise estimation and compensation block 2214 connected as shown. The outputs of the blocks 2404 and 2414 are coupled to a MIMO detection block 2405 and a decoding block 2406 connected as shown.

[0225] With the UE receiver 2400, although the DMRS can be transmitted in an SFN manner, the received signals from each TRP can be processed independently, which allows channel estimation and phase noise compensation to be performed separately for each TRP communication. The demodulated data corresponding to each TRP can then be combined, equalized, and decoded. Determination of default beam in multi-transmit latency transmission

[0226] Figure 27C and Figures 28A-28D Single DCI and multiple DCI M-TRP transmission schemes according to the subject matter disclosed herein are depicted respectively. Rel-15 introduced multiple transmission reception points (M-TRP) as a solution to improve cell edge performance. In M-TRP transmission schemes, different antenna ports of one or different channels can be within multiple TRPs that are typically non-co-located. M-TRP transmission can be divided into single DCI M-TRP category and multiple DCI M-TRP category. For single DCI M-TRP, a single PDCCH is transmitted to schedule one or multiple PDSCHs. The PDSCHs can be transmitted from different TRPs, such that different layers can be transmitted from different TRPs. Alternatively, all layers of a PDSCH can be transmitted from one TRP, while multiple PDSCHs can be multiplexed in time domain or frequency domain within the same transport block (TB). In multiple DCI M-TRP transmission, each TRS transmits its own PDCCH and DCI. Each DCI schedules one PDSCH with two layers of transmission. All layers of a given PDSCH can be transmitted from antenna ports within the same TRP.

[0227] Different multiplexing schemes can be applied for PDCCH transmission. With TDM multiplexing, the two sets of symbols of a transmitted PDCCH / two non-overlapping (in time) transmitted PDCCH repetitions / non-overlapping (in time) multi -opportunity transmitted PDCCH can be associated with different TCI states. With FDM multiplexing, the two sets of control channel element (CCE) / resource element group (REG) bundles of a transmitted PDCCH / two non-overlapping (in frequency) transmitted PDCCH repetitions / non-overlapping (in frequency) multi -opportunity transmitted PDCCH can be associated with different TCI states. For SDM (non-transparent SFN), two different DMRS ports are each associated with one different TCI state. Rel-17 does not support SDM PDCCH schemes. With SFN, the PDCCH DMRS can be associated with two TCI states in all REGs / CCEs of the PDCCH.

[0228] For non-SFN M-TRP PDCCH transmission, the following possibilities of no repetition, repetition, and multi -opportunity can be considered. For no repetition, one encoding / rate matching can be used for PDCCH with two TCI states. With this scheme, a single PDCCH candidate can be associated with two different TCI states. That is, some specific CCEs / REGs of the candidate can be associated with a first TCI state, while the rest of the CCEs / REGs are associated with a second TCI state. For repetition, the encoding / rate matching can be based on one repetition, and for other repetitions, the same encoded bits can be repeated. Each repetition has the same number of CCEs and encoded bits, and corresponds to the same DCI payload. For multi -opportunity, separate DCIs can schedule the same PDSCH / PUSCH / RS / TB / etc. or result in the same outcome.

[0229] For any of the above transmission schemes, to implement PDCCH transmission with two different TCI states, one approach can be to associate one control resource set (CORESET) with two different TCI states. Depending on the different multiplexing schemes of PDCCH transmission, the following schemes A-C can be used for one CORESET with two active TCI states:

[0230] Figure 29 Scheme A according to the subject matter disclosed herein is depicted, where one PDCCH candidate (in a given SS set) can be associated with two TCI states of a CORESET.

[0231] Figure 29 Scheme B according to the subject matter disclosed herein is depicted, where two sets of PDCCH candidates (in a given SS set) can be associated with two TCI states of a CORESET, respectively.

[0232] Figure 30 Scheme C is depicted in accordance with the subject matter disclosed herein, where two sets of PDCCH candidates can be associated with two corresponding sets of SS, where the two sets of SS can be associated with CORESETs, and each set of SS can be associated with only one TCI state of a CORESET.

[0233] For Scheme B and Scheme C, the following two cases can be considered for mapping between different PDCCH candidates with different TCI states.

[0234] Case 1: Two (or more) PDCCH candidates can be explicitly linked together (the UE knows the link before decoding).

[0235] Case 2: Two (or more) PDCCH candidates can not be explicitly linked together (the UE does not know the link before decoding).

[0236] As a different alternative to associating PDCCH candidates with two different TCI states, one SS set can be associated with two different CORESETs, where each CORESET is associated with a TCI state. Different SS and CORESET multiplexing schemes can also allow multiple TCI states for PDCCH candidates. With this scheme, two SS sets are associated with two CORESETs, where each CORESET can be configured with a different TCI state.

[0237] Default beam and RS specification

[0238] For single-DCI based NCJT in Rel-16, a UE can be configured with up to three CORESETs and ten search space sets on each of up to four bandwidth parts (BWPs) of a serving cell. A search space set can be associated with only one CORESET and one TCI state. Having PDCCHs with two TCI states in multi-TRP schemes impacts the default beam and RS specification, as they are specified in the current specification considering one TCI state of a CORESET. To illustrate, the default beam for PDSCH is derived based on the TCI state of the CORESET with the lowest ID. In addition, the default spatial relation and path loss RS (if not configured) can be derived based on the TCI state of the CORESET with the lowest ID or the TCI state with the lowest ID for PDSCH. In beam failure recovery, the beam failure detection RS (if not explicitly configured) is derived based on the TCI state of the responding CORESET for monitoring PDCCH.

[0239] The default TCI state for PDSCH can be determined as a single TCI state or a pair of TCI states. While a single TCI state can be applicable to PDSCH transmission schemes with single or multiple TCI states, a pair of TCI states can be applicable only to PDSCH transmission schemes with two different TCI states.

[0240] Single TCI state default beam

[0241] To determine the default beam for PDSCH reception, the following three methods are possible.

[0242] Method 1 (ignore CORESET with two TCI states): Generally, for multi-TRP scenarios, one solution to prevent any ambiguity on the default beam and RS determination at the UE can be that the default beam and RS specification can be determined based on CORESETs with single TCI state only. That is, the default beam, default spatial relation, and path loss RS for PDSCH can be derived based on the TCI state of the CORESET with the lowest ID among CORESETs with single TCI state. With Method 1, Rel-15 behavior can be reused, except that this method can consider only CORESETs associated with one TCI state.

[0243] Method 2 (lowest ID CORESET with two TCI states is an error case): An alternative solution can be that the specification does not allow the lowest CORESET index to be configured with two TCI states. With this solution, it can not be expected that a UE is configured with a CORESET and associated one or two TCI states such that the CORESET with the lowest ID in the latest slot in which the UE monitors PDCCH can be associated with two different TCI states. This can be a reuse of Rel-15 behavior.

[0244] Method 3 (reference TCI state / TRP): Yet another method can be that one of the TRPs and / or its corresponding TCI state can be configured as the reference TRP and / or reference TCI state, where the default beam and RS specification can be derived based on this particular TCI state. Method 3 can be described as follows.

[0245] Each TCI state can also be associated with a TRP by TRP index 1 or 2. Each CORESET can be associated with one or two TCI states. Specifically, a MAC-CE activates a single TCI state or a pair of TCI states (TCI state #1, TCI state #2). The gNB can configure a UE via RRC with a reference TRP index t ref ∈ {1, 2} for default beam determination. The UE derives the default beam and RS based on the TCI state of the CORESET with the lowest ID among CORESETs with the reference TRP index t refThe default TCI state is determined in the CORESET associated with the TCI state. Among the CORESETs including the TCI state associated with the reference TRP index, the CORESET with the lowest ID is selected. One example is shown in Table 2 below, where it can be assumed that the UE is configured with reference TRP index t ref = 2. The default TCI state can be TCI state 3 in CORESET ID #2.

[0246] Table 2. Example default TCI state determination for Method 3

[0247]

[0248] Method 4 (Reference TCI state entry index independent of CORESET): Method 4 can include the concept of reference TRP that is not defined. With this method, the UE can be configured with TCI states where there is no explicit association between TCI states and TRPs. A MAC CE can activate one or more TCI states for each CORESET. The activated TCI states can be in the form of a P-tuple of P entries (TCI-State #il, TCI-State #i2, …, TCI-State #i P P can be the same or different for different CORESETs, P = 1, 2, 3, …. The gNB can configure the UE with a reference TCI state index i ref Among the CORESETs with TCI state tuples including index i ref , the CORESET with the lowest ID is selected. Then, the default TCI state can be the i ref th entry of the tuple associated with the selected CORESET.

[0249] Alternatively, the reference TCI state entry index i ref may be predetermined by specifying that a predetermined TCI state (e.g., the first or second) in each CORESET is always considered as the reference TCI state.

[0250] As an example, the gNB can configure the UE with i ref = 2. The UE can determine the default TCI state from the CORESETs with at least two TCI states (i.e., the length of the activated tuple can be 2 or more). The second entry can be selected as the default TCI state among these CORESETs.

[0251] The default beam can always be determined from the CORESET with the lowest CORESET ID, regardless of the number of active TCI states of the CORESET, the configuration of the reference TRP, or the reference TCI state index, etc. When the gNB configures the reference TCI state index as i ref When = 1, this can be achieved through method 4. Method 4 can also be alternatively described as follows.

[0252] Method 4-0 (a special case of Method 4): The default TCI state can always be determined from the CORESET with the lowest CORESETID. If a CORESET has a single TCI state, that TCI state can be determined as the default TCI state. If a CORESET has multiple TCI states, the default TCI state can be determined as the i-th TCI state. ref Each TCI state. ref The reference TCI state index can be configured to the UE via RRC, or it can be predetermined. It can be specified that a predetermined TCI state (e.g., first or second state) in each CORESET is always considered the reference TCI state. Alternatively, the reference index can be configured individually for each CORESET.

[0253] Method 5 (Reference TCI State Entry Index Based on CORESET): Using this method, the UE can be configured with TCI states, where there may be no explicit association between the TCI states and TRPs. MAC-CE can activate one or more TCI states for each CORESET. Activated TCI states can have P entries (TCI-State#i1, TCI-State#i2, ..., TCI-State#i...). P The P tuple is used to represent the UE. For different CORESETs, P can be the same or different, P = 1, 2, 3… The gNB can configure the reference TCI state index i for each CORESET for the UE. ref Then, a default TCI state can be selected from the TCI states of the CORESET with the lowest CORESET ID. The default TCI state can be the i of the tuple associated with the selected CORESET. ref Entries, where i ref It can be the reference TCI status index of the selected CORESET.

[0254] HST-SFN transmission can be a coherent joint transmission that uses only one PDCCH to allocate one set of PDSCH resources. That is, the same PDCCH can be transmitted from multiple TRPs simultaneously. From the UE’s perspective, the additional downlink transmission can be interpreted as an additional downlink delay spread component originating from a single TRP. Having the PDCCH with two TCI states in HST scenarios can mean that a CORESET in Rel-17 can be configured with two TCI states. The default beam and RS specification in HST scenarios can follow the Rel-16 behavior, using the TCI state of the PDCCH transmitted from the reference TRP. In a TRP-based frequency offset pre-compensation scheme, the reference TRP can be the TRP used by the gNB as a reference for frequency offset compensation. This can make the reference TRP the primary TRP, especially in the case of a beam failure event. The reference TRP can be indicated semi-statically to the UE a specific TCI state, and the default TCI state can be selected from the CORESET with the lowest ID that has a TCI state associated with the reference TRP. Another approach can be that one of the TCI states in the CORESET can be indicated semi-statically to the UE as the reference TCI state, or a predetermined TCI state (i.e., first or second) in each CORESET can be designated as the reference TCI state. This reference TCI state can then be used as the default TCI state to determine the default beam and RS. Another solution is that the default beam and RS specification can be determined based only on the CORESET with a single TCI state, or the specification can make the lowest CORESET index in HST scenarios always have a single TCI state.

[0255] The TCI state format can include two pairs of different QCL information and reference signals, as shown in bold below:

[0256]

[0257] With this new enhanced Rel-17 TCI format, a PDCCH with two TCI states in HST scenario can be associated with a CORESET with one TCI state. Therefore, the default beam and RS specification can follow Rel-16 behavior and can be derived based on the TCI state of the CORESET with the lowest ID. However, the TCI state of the CORESET with the lowest ID can contain two pairs of QCL RS and can cause ambiguity in the default beam and RS determination at the UE. To solve this problem, one solution can be that the default beam and RS specification can be determined based on the CORESET with the TCI state containing only one pair of QCL information (i.e., legacy TCI) only. Alternatively, the specification can restrict the lowest CORESET index in HST scenario to always have a legacy TCI state instead of the enhanced Rel-17 format. Another approach can be that one of the QCL information pairs or one of the QCL RS in the TCI state of the CORESET with the lowest ID can be semi-statically indicated to the UE as the reference QCL information pair or reference QCL RS. It can also be specified that the predetermined (i.e., first or second) QCL information pair / QCL RS in each TCI state is always considered to be used as the reference for the default beam and RS. Another approach can be that the reference TRP can be semi-statically indicated to the UE with the QCL information pair and the default beam and RS can be selected from the CORESET with the lowest ID with the TCI state associated with the reference TRP.

[0258] To improve the reliability of PDCCH transmission in multi-TRP cells, especially in scenarios where TRPs can be blocked, different PDCCH schemes can be considered. Different PDCCH schemes have been presented and with these schemes, PDCCH can be repeated within or across different SS sets. It can also be transmitted with a scheme called multi- opportunity, where multiple PDCCH schedule the same PDSCH / PUSCH or uplink / downlink channels / signals. From different perspectives, the repeated PDCCH can be associated with one or two CORESETs. As an example, PDCCH can be repeated across or within a synchronization signal (SS) set. As a different example, PDCCH can be transmitted such that its first repetition is transmitted in a first SS associated with CORESET#1 and the second repetition can be transmitted in a second SS set associated with CORESET#2. Figure 31 Examples of the repetition schemes disclosed herein are depicted.

[0259] For one CORESET and two TCI states, the default PDCSH beam can be determined based on the TCI state of the CORESET that is associated with the latest repetition of PDCCH in the slot.

[0260] Method 6 (latest TCI state associated with repeated PDCCH in the same CORESET): With this method, each CORESET can be associated with one or two TCI states. Specifically, a MAC-CE activates a single TCI state for a CORESET, in which case it also indicates which TRP number the activated TCI state can be associated with, or a MAC-CE activates a pair of TCI states (TCI state #1, TCI state #2), where TCI state #1 and #2 correspond to the first and second TRP, respectively. The default TCI state is selected from the CORESET with the lowest ID that is associated with two different TCI states. Among the two TCI states of the CORESET with the lowest ID, the TCI state associated with the latest SS set is selected as the default TCI state.

[0261] Method 7 (latest TCI state associated with repeated PDCCH with different CORESET): With this method, each CORESET can be associated with one or two TCI states. Specifically, a MAC-CE activates a single TCI state for a CORESET, in which case the MAC-CE also activates the TRP number that the TCI state can be associated with, or a MAC-CE activates a pair of TCI states (TCI state #1, TCI state #2), where TCI state #1 and #2 correspond to the first and second TRP, respectively. The default TCI state can be selected from the CORESET with the lowest ID.

[0262] If a CORESET is associated with two different TCI states. The TCI state associated with the latest SS set is selected as the default TCI state from among the two TCI states of the CORESET with the lowest ID.

[0263] If a CORESET is associated with a single TCI state, and it is linked to a linked CORESET, the default TCI state can be selected as the TCI state of the CORESET or the linked CORESET, whichever ends later in the slot.

[0264] Alternatively, either of the methods 6 and 7 can be used with modifications (i.e., the earliest SS set is selected among the linked sets).

[0265] Two TCI state default beam

[0266] As mentioned before, the default beam can also be determined as a pair of TCI states.

[0267] The pair of default TCI states can be determined from the configured CORESETs with two different TCI states.

[0268] Method 8 (Default TCI state is a pair and depends on CORESET): If the UE is configured with one or more CORESETs, where at least one CORESET can be associated with two TCI states, the default TCI state for PDSCH can be determined as follows. The UE determines the CORESET with the lowest ID among the CORESETs associated with two TCI states. The default TCI state can then be determined as the pair of TCI states associated with the CORESET with the lowest CORESET ID.

[0269] Method 8 can be applicable when there is at least one CORESET with two different TCI states. If there is no CORESET with two TCI states, the default beam can be determined as the TCI state of the CORESET with the lowest CORESET ID.

[0270] Alternatively, the default TCI state can be determined as selected from a set of single or pair of TCI states activated by a MAC-CE for PDSCH reception.

[0271] Method 9 (Default TCI state is a pair and lowest PDSCH codepoint): When a MAC CE activates a set of TCI states for PDSCH reception, such that there can be at least one TCI codepoint with two different TCI states, the default TCI state for PDSCH can be determined as the TCI state corresponding to the lowest TCI codepoint among the TCI codepoints containing two different TCI states.

[0272] TCI state application for PDSCH

[0273] Once the UE determines the default TCI state pair (A, B), if the PDSCH follows the default TCI state, the UE should apply the TCI state (A, B) according to the mapping. However, before the DCI decoding, the UE can not know which resources are used for each TCI state in the PDSCH transmission. The following provides solutions to solve this problem.

[0274] SDM, SFN, and HST PDSCH

[0275] For SDM PDSCH scheme, a specific number of ports of PDSCH can be associated with a first TCI state and a specific other port can be associated with a second TCI state. Therefore, regardless of time / frequency resource allocation, a UE can be expected to receive OFDM symbols with two TCI states without DCI decoding. Similarly, for SFN and HST PDSCH, DMRS ports can be associated with two TCI states and a UE does not need resource allocation to apply TCI states.

[0276] TDM PDSCH

[0277] For TDM PDSCH, a UE can need to know resource allocation to apply default TCI states. With one solution, a DCI decoding delay time can be defined to confirm DCI decoding delay. A UE receives a symbol before the DCI decoding delay with a first TCI state and receives a next symbol according to resource allocation indicated in DCI. The following method can define UE behavior. In the following method, a “default TCI state threshold time” can be defined according to UE capability and can be measured from the end of PDCCH scheduling PDSCH.

[0278] Method 10 (one state until DCI decoding delay and two states until threshold): If a UE is configured with RRC parameters indicating reception of PDSCH with two default TCI states and at least one TCI codepoint indicates two TCI states and the UE is configured to receive single DCI M-TRP TDM PDSCH, the UE can be configured via RRC or can be given a predefined DCI decoding delay T DCI decoding . The UE can determine default TCI states as (A, B) and receive symbols as follows.

[0279] From the first symbol of a CORESET in which a UE monitors PDCCH until T DCI,decoding , after the end of the CORESET, the UE receives symbols assuming the first TCI state A. From T DCI,decoding , after the end of the CORESET, until the default TCI state threshold time, the UE receives symbols according to time domain resource allocation indicated by DCI with both TCI states A and B.

[0280] Figure 32 An example of PDSCH scheduling and UE behavior according to Method 10 is depicted. From the beginning of PDCCH to the second vertical dashed line 2901, the UE receives symbols 2902 with the first TCI state from the second vertical dashed line 2901, the UE receives symbols according to time domain resource indicated in DCI. The time domain resource can indicate the UE to receive as Figure 33The PDSCH occasion shown, the UE will thus know to receive the second PDSCH occasion 2903 with the second TCI state.

[0281] In method 10, the UE receives symbols with a single TCI state before the DCI decoding delay. This can prevent the gNB from scheduling two TCI states before the DCI decoding delay. This problem is solved in method 11.

[0282] Method 11 (two states until DCI decoding delay and two states until threshold): Figure 34 An example of method 11 according to the subject matter disclosed herein is depicted. If the UE is configured with an RRC parameter indicating reception of PDSCH with two default TCI states, at least one TCI codepoint indicates two TCI states, and the UE is configured to receive a single DCI M-TRP TDM PDSCH, the UE can be configured via RRC or can be given a predefined DCI decoding delay T DCI decoding . The UE can determine the default TCI states as (A, B) and receive symbols as follows.

[0283] From the first symbol of the CORESET in which the UE monitors PDCCH until T DCI,decoding , after the end of the CORESET, the UE can receive symbols assuming the first TCI state A and the second TCI state B according to the fixed time locations at which symbols are mapped to the first and second TCI states. From T DCI,decoding , after the end of the CORESET, until the default TCI state threshold time, the UE receives symbols according to the time domain resource allocation indicated by the DCI with both TCI states A and B.

[0284] Alternatively, the UE can receive only one TCI state before the threshold or two TCI states at the fixed time locations.

[0285] Method 12 (one state until threshold): If the UE is configured with an RRC parameter indicating reception of PDSCH with two default TCI states, at least one TCI codepoint indicates two TCI states, and the UE is configured to receive a single DCI M-TRP TDM PDSCH, the UE can determine the default TCI states as (A, B) and receive symbols with TCI states as follows.

[0286] Figure 35 An example of method 12 according to the subject matter disclosed herein is depicted. From the first symbol of the CORESET until the default TCI state threshold time, the UE receives symbols with TCI state A.

[0287] Method 13 (two states until threshold):Figure 36 An example of method 13 according to the subject matter disclosed herein is depicted. If the UE is configured with an RRC parameter indicating reception of PDSCH with two default TCI states, at least one TCI codepoint indicates two TCI states, and the UE is configured to receive single-DCI M-TRP TDM PDSCH, the UE can determine the default TCI states as (A, B) and receive the symbols with TCI states as follows.

[0288] From the first symbol of the CORESET until the default TCI state threshold time, the UE receives symbols with both TCI states A and B and according to the fixed time locations of the symbols mapped to the first and second TCI states.

[0289] How to determine the fixed time locations

[0290] The fixed time locations in methods 11 and 13 are the symbols that the UE receives with a particular TCI state among the two default states. To determine the time locations of each TCI state, first determine the “fixed window”. The symbols within the “fixed window” can be assigned to one of the two TCI states. The window starts from the first symbol of the CORESET and can end at the threshold time or the time indicated by the DCI decoding delay or the time indicated by the default TCI state threshold, i.e., the start of the next earliest CORESET in which the UE monitors PDCCH.

[0291] Case 1: Intra-slot TDM

[0292] In the case of intra-slot TDM, the “fixed window” starts from the start symbol of the CORESET and ends at the start of the earliest next CORESET or the time indicated by the DCI decoding delay, whichever is earlier. Once the fixed window is determined, the set of symbols in the window are mapped to the first and second TCI states as follows.

[0293] Two chunks in each slot: If a slot has N symbols in the fixed window, the first N1 symbols are mapped to the first TCI state and the second N-N1 symbols are mapped to the second TCI state, where N1 can be RRC configured, or fixed predetermined, or Typical selection of slots with N symbols in the window is

[0294] ​ An example of intra-slot TDM according to the subject matter disclosed herein is depicted.

[0295] Multiple contiguous chunks with alternating TCI states: As a different approach, if a slot has N symbols in a fixed window, the N symbols are grouped into L groups, where group 1 includes the first N1 symbols, group 2 includes the next N2 symbols, group 3 includes the next N3 symbols, and so on, where each group includes an even number of symbols except possibly the first group or the last group. For groups with an even number of symbols, the first half of the symbols can be mapped to the first TCI state and the second half can be mapped to the second TCI state. For groups with an odd number of 2K+1 symbols, the first K symbols can be mapped to the first TCI state and the next K+1 can be mapped to the second TCI state. ​ An example of multiple contiguous chunks with alternating TCI states (where L=2) is depicted in accordance with the subject matter disclosed herein.

[0296] Case 2: Inter-slot TDM

[0297] Similar to the intra-slot scheme can be considered for inter-slot TDM, with the modification that the TCI states alternate in two consecutive slots. In the case of inter-slot TDM, the “fixed window” starts from the start symbol of the CORESET and ends at the start of the earliest next CORESET or the time indicated by the DCI decoding delay, whichever is earlier. Once the fixed window is determined, the set of symbols in the window can be mapped to the first and second TCI states as follows.

[0298] Multiple contiguous slots with alternating TCI states: If N contiguous slots overlap with a fixed window, the symbols of the first, third, fifth, and so on slots can be mapped to the first TCI state and the symbols of the second, fourth, sixth, and so on slots can be mapped to the second TCI state. ​ An example of multiple contiguous slots with alternating TCI states based on the inter-slot TDM case 2 is depicted in accordance with the subject matter disclosed herein.

[0299] FDM PDSCH

[0300] With the FDM PDSCH scheme, the first half of the resource blocks can be associated with the first TCI state and the second half can be associated with the second TCI state. In principle, the default TCI state and UE behavior for the FDM PDSCH scheme can also be determined with any of the methods 10 to 11, where the fixed time position can be replaced by a fixed frequency position and the frequency positions (RBs) can be mapped to the first and second TCI state. A fixed window can be determined, which includes a starting RB and a length according to the number of RBs. The fixed window can also be defined by a set of bitmaps, which indicate which RBs are included in the window. Once the window is determined to include N RBs, the first N1 RBs can be mapped to the first TCI state and the second N-N1 RBs can be mapped to the second TCI state.

[0301] An example of such a scheme is as follows. The fixed window can be selected as the entire active BWP. The active BWP can be split into two sets of equal number of RBs. The UE receives the first set of RBs with the first TCI state and the second set with the second TCI state until the UE decodes the DCI. After the UE decodes the DCI, the UE receives the set of allocated PDSCH RBs according to the frequency domain allocation. To accommodate such behavior, it can be desirable for the gNB to transmit the FDM PDCSH such that the first half of the scheduled RBs are located in the first half of the BWP and the second half of the scheduled RBs are located in the second half of the BWP. ​ An example of a FDMPDSCH scheme is depicted in accordance with the subject matter disclosed herein.

[0302] Example TP of TS 38.214

[0303] Antenna port quasi co-location

[0304] <omitted unchanged>

[0305] Independent of the configuration of tci-PresentInDCI and tci-PresentDCI-1-2 in RRC connected mode, if the offset between the reception of the DL DCI and the corresponding PDSCH is less than the threshold timeDurationForQCL and at least one configured TCI state of the serving cell for the scheduled PDSCH contains qcl-Type set to 'typeD',

[0306] - The UE can assume that the DM-RS ports of PDSCH of the serving cell are quasi co-located with the RS(s) of the QCL parameter(s) indicated with respect to the PDCCH quasi co-location of the CORESET associated with the monitoring search space with the lowest controlResourceSetld among the one or more CORESETs within the active BWP of the serving cell in the latest slot in which the UE monitors the one or more CORESETs. In this case, if the qcl-Type is set to 'typeD' for the PDSCH DM-RS, which is different from the qcl-Type of the PDCCH DM-RS in which they overlap on at least one symbol, the UE is expected to receive the PDCCH associated with the CORESET first. This also applies to the case of intra-band CA (when PDSCH and CORESET are in different component carriers).

[0307] - If the UE is configured with enableDefaultTCIStatePerCoresetPoolIndex and the UE is configured by higher layer parameter PDCCH-Config containing two different values of coresetPoolIndex in different ControlResourceSets,

[0308] - The UE can assume that the DM-RS ports of PDSCH associated with the value of coresetPoolIndex of the serving cell are quasi co-located with the RS(s) of the QCL parameter(s) indicated with respect to the PDCCH quasi co-location of the CORESET associated with the monitoring search space with the lowest controlResourceSetld among the CORESETs configured with the same value of coresetPoolIndex as the PDCCH scheduling the PDSCH, located in the latest slot in which the one or more CORESETs associated with the same value of coresetPoolIndex as the PDCCH scheduling the PDSCH are monitored by the UE. In this case, if 'QCL-TypeD' of the PDSCH DM-RS is different from 'QCL-TypeD' of the PDCCH DM-RS in which they overlap on at least one symbol and they are associated with the same coresetPoolIndex, the UE is expected to receive the PDCCH associated with the CORESET first. This also applies to the case of intra-band CA (when PDSCH and CORESET are in different component carriers).

[0309] - If the UE is configured with enableTwoDefaultTCI-States and at least one TCI codepoint indicates two TCI states, the UE can assume that the DM-RS ports of PDSCH or PDSCH transmission occasion of the serving cell are quasi co-located with respect to the RS(s) associated with the TCI state corresponding to the lowest codepoint among the TCI codepoints containing two different TCI states. When the UE is configured by higher layer parameter repetitionScheme set to 'tdmSchemeA' or configured with higher layer parameter repetitionNumber, according to clause 5.1.2.1, the mapping of TCI states to PDSCH transmission occasions is determined based on the activated TCI states in the slot with the first PDSCH transmission occasion by replacing the indicated TCI states with the TCI state corresponding to the lowest codepoint among the TCI codepoints containing two different TCI states. The UE can also assume that the DM-RS ports of PDSCH or PDSCH transmission occasion on the symbol set starting from the first symbol of the CORESET where the scheduling PDCCH is transmitted are quasi co-located with respect to the RS associated with the QCL parameters of the first TCI state corresponding to the lowest codepoint among the TCI codepoints containing two different TCI states, where N3 is determined according to clause 9.2.3 of TS 38.213. In this case, if 'QCL-TypeD' of the two TCI states corresponding to the lowest codepoint among the TCI codepoints containing two different TCI states is different from 'QCL-TypeD' of PDCCH DM-RS where they overlap on at least one symbol, the UE is expected to receive PDCCH associated with this CORESET first. This also applies to the case of intra-band CA (when PDSCH and CORESET are in different component carriers).

[0310] - In all the above cases, if none of the configured TCI states of the serving cell of the scheduled PDSCH is configured with qcl-Type set to 'typeD', the UE will obtain the other QCL assumption from the TCI state indicated for the PDSCH for which it is scheduled, regardless of the time offset between the reception of the DL DCI and the corresponding PDSCH.

[0311] <omitted unchanged>

[0312] Beam failure

[0313] To address beam failure recovery in HST scenarios with TRP-based frequency offset pre-compensation, two different scenarios can be considered. First, the reference TRP experiences beam failure, and second, the non-reference TRP experiences beam failure. For both cases, each TRP can be explicitly configured by RRC or implicitly configured by TCI state up to two periodic 1-port CSI-RS per BWP for beam failure detection. The downlink RS for the new beam identification set can be based on SSB and CSI-RS and can be explicitly and separately configured for each TRP. Furthermore, since two TCIs are activated for PDCCH, each TCI state can implicitly correspond to the beam failure detection RS of the corresponding TRP if not configured. When one of the TRPs experiences beam failure, the reception at the UE can fall back to the single TRP scenario. That is, when the UE detects beam failure, the UE should switch the channel estimation and other signal processing algorithms to those used for single TRP transmission.

[0314] In HST-SFN scenarios with TRP-based frequency offset pre-compensation, if the reference TRP experiences beam failure, there will be some disruption of QCL information relations (i.e., Doppler shift related properties) on the non-reference TRP transmission due to the beam failure of the reference TRP. To illustrate, when the network pre-compensates the frequency offset for TRS and all other downlink transmissions (including PDCCH, DMRS, and PDSCH), the QCL RS of the TRS transmitted from the non-reference TRP can be the TRS transmitted from the reference TRP or the QCL RS of the TRS transmitted from the reference TRP with QCL Type B. Similarly, when the network pre-compensates the frequency offset for all downlink transmissions (but not for the TRS, QCL RS of PDCCH), the PDSCH DMRS of the non-reference TRP can be the TRS transmitted from the reference TRP with QCL Type B. This means that beam failure on the reference TRP transmission can also interrupt the PDCCH and PDSCH reception at the non-reference TRP. In this case, one solution can use the QCL information of the latest TRS received from the reference TRP before the beam failure is identified and can be used for continued DL transmission from the non-reference TRP. That is, the UE monitors the PDCCH using only the TCI states associated with the non-reference TRP and reuses the associated TCI states of the reference TRP in the last received CORESET of the latest slot before the UE identifies the beam failure. Thus, PDSCH reception can also reuse the associated TCI states of the reference TRP in the latest slot before the UE identifies the beam failure.

[0315] Embodiments of the subject matter and operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Embodiments of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or additionally, the program instructions can be encoded as propagated signals, e.g., machine-generated electrical, optical, or electromagnetic signals, that are generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. The computer storage medium can be, or include, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium can also be, or include, one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices). Additionally, the operations described in this specification can be implemented as operations performed by a data processing apparatus on data stored on one or more computer-readable storage devices or received from other sources.

[0316] While this specification can include many specific embodiments, these embodiments should not be construed as limiting the scope of any requirements claims, but as merely describing specific features, aspects and features of certain embodiments. The specific features described in this specification under separate headings of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described under a single embodiment can be implemented separately or in any suitable subcombination in multiple embodiments. Additionally, although features can be described above as functioning in a specific combination, one or more features from a claimed combination can be deleted in some instances, and the claimed combination can be directed to a subcombination or variation of a subcombination.

[0317] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring this particular order or sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing can be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated in a single software product or packaged into multiple software products.

[0318] Thus, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, acts recited in the claims can be performed in a different order and still achieve desirable results. Additionally, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous.

[0319] As will be recognized by those skilled in the art, the innovative concepts described in this document can be modified and varied widely. Accordingly, the scope of the claimed subject matter is not to be limited to any particular illustrative teachings discussed above, but is instead defined by the following claims.

Claims

1. A wireless communication device, comprising: a receiver configured to receive a first reference signal and a second reference signal transmitted from a first transmission reception point, TRP, over a wireless network, the first reference signal corresponding to a quasi co-location reference signal, QCL RS, of the second reference signal, the receiver further configured to determine delay spread and average delay information of a path between the first TRP and the device based on the first reference signal, wherein the receiver is further configured to receive a fifth reference signal transmitted from the first TRP and a second TRP over the wireless network, the fifth reference signal comprising a dual-port phase tracking reference signal, PTRS, wherein a first port of the dual-port PTRS conveys phase tracking information of the first TRP and a second port of the dual-port PTRS conveys phase tracking information of the second TRP.

2. The wireless communication device of claim 1, wherein, the first reference signal comprises a tracking reference signal, TRS, and the second reference signal comprises a physical downlink shared channel, PDSCH, demodulation reference signal, DMRS.

3. The wireless communication device of claim 1, wherein, the first reference signal comprises one of a tracking reference signal, TRS, and a synchronization signal block, SSB, and the second reference signal comprises a TRS.

4. The wireless communication device of claim 1, wherein, the receiver is further configured to receive a third reference signal from the second TRP, the third reference signal comprising Doppler shift and Doppler spread information and corresponding to a QCL RS of a fourth reference signal transmitted from the second TRP or corresponding to the second reference signal transmitted from the first TRP in a single frequency network, SFN, manner.

5. The wireless communication device of claim 4, wherein, the second TRP comprises a reference TRP, the first TRP comprises a non-reference TRP, and the first reference signal pre-compensates, in a high speed train, HST, scenario, a Doppler shift at the device relative to the second TRP.

6. The wireless communication device of claim 4, wherein, the second reference signal is associated with two transmission configuration indicator, TCI, states corresponding to the first reference signal and the third reference signal.

7. The wireless communication device of claim 4, wherein, the receiver is further configured to receive a physical downlink control channel, PDCCH, DMRS associated with two transmission configuration indicator, TCI, states from the first TRP and the second TRP, and wherein the receiver is further configured to determine a TCI state of a PDSCH DMRS scheduled by the PDCCH as one of the two TCI states.

8. The wireless communication device of claim 1, wherein, the receiver is further configured to receive a control message transmitted from the first TRP over the wireless network to dynamically update a configuration of one of the first reference signal and the second reference signal, and wherein the receiver is further configured to determine, based on the control message, information of at least periodicity for one of the first reference signal and the second reference signal based on a change in movement of the device relative to the first TRP.

9. The wireless communication device of claim 1, wherein, the receiver is further configured to receive a control message transmitted from the first TRP over the wireless network, the control message dynamically updating quasi co-location information of one of the first reference signal and the second reference signal, and the receiver is further configured to receive a control message transmitted from the first TRP over the wireless network, the control message dynamically updating quasi co-location information of one of the first reference signal and the second reference signal, and The receiver is further configured to determine, based on the control message, information for at least one of Doppler shift, Doppler spread, average delay, delay spread, and spatial receiver parameters based on a change in movement of the device relative to the first TRP.

10. A wireless network comprising: a first transmission reception point, TRP, and a second TRP, the first TRP comprising a first transmitter configured to transmit, over a wireless network, a first reference signal and a second reference signal to a device, the first reference signal corresponding to a Quasi Co-Location Reference Signal, QCL RS, of the second reference signal and being used by the device to determine delay spread and average delay information of a path between the first TRP and the device, the first TRP and the second TRP are configured to transmit, over a wireless network, a fifth reference signal to the device, the fifth reference signal comprising a dual-port Phase Tracking Reference Signal, PTRS, wherein a first port of the dual-port PTRS conveys phase tracking information of the first TRP and a second port of the dual-port PTRS conveys phase tracking information of the second TRP.

11. The wireless network of claim 10, wherein, the first reference signal comprises a Tracking Reference Signal, TRS, and the second reference signal comprises a Physical Downlink Shared Channel, PDSCH, Demodulation Reference Signal, DMRS.

12. The wireless network of claim 10, wherein, the first reference signal comprises one of a Tracking Reference Signal, TRS, and a Synchronization Signal Block, SSB, and the second reference signal comprises a TRS.

13. The wireless network of claim 10, wherein, the second TRP comprises a second transmitter configured to transmit a third reference signal and a fourth reference signal, the third reference signal comprising Doppler shift and Doppler spread information and corresponding to a QCL RS of the fourth reference signal transmitted from the second transmitter or to the second reference signal transmitted from the first TRP in a Single Frequency Network, SFN, manner.

14. The wireless network of claim 13, wherein, the second TRP comprises a reference TRP, the first TRP comprises a non-reference TRP, and the first reference signal pre-compensates, in a High-Speed Train, HST, scenario, Doppler shift at the device relative to the second TRP.

15. The wireless network of claim 13, wherein, the second reference signal is associated with two Transmission Configuration Indicator, TCI, states corresponding to the first reference signal and the third reference signal.

16. The wireless network of claim 13, wherein, the first TRP and the second TRP are each configured to transmit, to the device, a Physical Downlink Control Channel, PDCCH, DMRS associated with two Transmission Configuration Indicator, TCI, states, from which the device determines a TCI state of a PDSCH DMRS scheduled by the PDCCH to be one of the two TCI states.

17. The wireless network of claim 10, wherein, the first TRP is configured to transmit, over a wireless network, a control message to the device to dynamically update a configuration of one of the first reference signal and the second reference signal, and the device determines, from the control message, information for at least periodicity of the one of the first reference signal and the second reference signal based on a change in movement of the device relative to the first TRP.

18. The wireless network of claim 10, wherein, the first TRP is further configured to transmit, to the device, a control message transmitted over a wireless network, and the first TRP is further configured to transmit, to the device, a control message transmitted over a wireless network, and wherein the control message dynamically updates quasi co-location information of one of the first reference signal and the second reference signal and includes at least one of a changed Doppler shift, Doppler spread, average delay, delay spread, and spatial receiver parameters based on movement of the device relative to the first TRP.

Images