Methods, apparatus, systems, and procedures for uplink (UL) channel reciprocity

Abstract

To provide methods, apparatuses, systems and procedures using UL channel reciprocity.SOLUTION: Methods, apparatuses and systems are disclosed. One representative method implemented by a wireless transmit / receive unit includes determining a first beamforming matrix; transmitting, to a network entity, an indication of the first beamforming matrix; and receiving, from the network entity, an indication of a second beamforming matrix determined by the network entity from at least the first beamforming matrix, for beamforming data for transmission.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to the field of wireless communication, and more particularly to methods, apparatus, systems, and procedures for using UL channel reciprocity (channel interdependence). [Background technology]

[0002] This application claims priority under U.S. Provisional Patent Application No. 62 / 445941 filed on 13 January 2017, U.S. Provisional Patent Application No. 62 / 416476 filed on 2 November 2016, U.S. Provisional Patent Application No. 62 / 400969 filed on 28 September 2016, and U.S. Provisional Patent Application No. 62 / 373203 filed on 10 August 2016, the contents of which each of these is incorporated herein by reference as if fully described.

[0003] Generally, conventional bidirectional communication systems have channel feedback. [Overview of the project] [Problems that the invention aims to solve]

[0004] The use of channel reciprocity can enable (for example, be key to the success of) wireless communication systems (e.g., future wireless communication systems). [Means for solving the problem]

[0005] In one typical embodiment, the message may include, as first precoding constraint information, information indicating any of the following: (1) a set of broadband antenna weights, (2) one or more sets of subband antenna weights, (3) a range of broadband antenna weights, and / or (4) one or more ranges of subband antenna weights.

[0006] In one representative embodiment, the WTRU 102 can select one or more specific antenna weights from the antenna weights indicated within a message as the second precoding constraint information.

[0007] In one representative embodiment, the message can indicate or include, as the first precoding constraint information, a codeword associated with a codebook or a specific set of codewords from which the WTRU 102 should select for UL MIMO communication.

[0008] A more detailed understanding can be obtained from the following detailed description, given by way of example, in conjunction with the drawings attached hereto. The figures within such drawings are, like the detailed description, examples. Therefore, the figures and the detailed description should not be regarded as limiting, and other equally effective examples are possible and may exist. Further, like reference numerals within the figures indicate like elements.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a system diagram showing an exemplary communication system capable of implementing one or more of the disclosed embodiments. [Figure 2] FIG. is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) that can be used within the communication system shown in FIG. 1. [Figure 3] FIG. is a system diagram showing an exemplary radio access network and another exemplary core network that can be used within the communication system shown in FIG. 1. [Figure 4] FIG. is a system diagram showing another exemplary radio access network and another exemplary core network that can be used within the communication system shown in FIG. 1. [Figure 5] FIG. is a system diagram showing a further exemplary radio access network and a further exemplary core network that can be used within the communication system shown in FIG. 1. [Figure 6] This figure shows a typical procedure for asymmetric interference (AI) avoidance for uplink (UL) multiple input multiple output (MIMO) systems. [Figure 7] This diagram shows a typical procedure using single-space stream transmission and a single codebook. [Figure 8] This diagram shows a typical procedure using multi-space stream transmission and a single codebook. [Figure 9] This diagram shows a typical procedure using WTRU-assisted interference adjustment. [Figure 10A] This diagram shows the procedure for using beamformed transmit diversity. [Figure 10B] This diagram shows the procedure for using beamformed transmit diversity. [Figure 11] This is a diagram showing the interference source. [Figure 12] This figure shows typical methods implemented by WTRU. [Figure 13] This figure shows another typical method implemented by WTRU. [Figure 14] This figure shows further representative methods implemented by WTRU. [Figure 15] This figure shows additional representative methods implemented by WTRU. [Figure 16] This figure shows another representative method implemented by WTRU. [Figure 17] This figure shows additional representative methods implemented by WTRU. [Figure 18] This figure shows another typical method implemented by WTRU. [Figure 19] This figure shows typical methods implemented by NE. [Figure 20] This figure shows another typical method implemented by NE. [Figure 21] This figure shows further representative methods implemented by NE. [Figure 22]This figure shows additional typical methods implemented by NE. [Figure 23] This figure shows further typical methods implemented by WTRU for transmit diversity mode. [Figure 24] This diagram illustrates typical methods implemented by WTRUs for UL MIMO communication management. [Figure 25] This diagram illustrates typical methods implemented by network engineers (NEs) for UL MIMO communication management. [Modes for carrying out the invention]

[0010] Methods, apparatus, and systems are disclosed. One typical method implemented by a wireless transceiver unit includes the steps of: determining a first beamforming matrix; transmitting a representation of the first beamforming matrix to a network entity; and receiving from the network entity a representation of a second beamforming matrix determined by the network entity from at least the first beamforming matrix, for beamforming data to be transmitted.

[0011] A detailed description of explanatory embodiments can now be given with reference to the figures. However, it should be understood that while the present invention can be described in relation to representative embodiments, it is not limited thereto, and other embodiments can be used, or modifications and additions can be made to the described embodiments without departure in order to perform the same functions as the present invention.

[0012] Typical embodiments will generally be shown using wireless network architectures from this point forward, but any number of different network architectures can be used, including, for example, networks having wired and / or wireless components.

[0013] Figure 1 shows an exemplary communication system 100 that can implement one or more disclosed embodiments. The communication system 100 can be a multiple access system that provides content such as voice, data, video, messaging, and broadcast to multiple wireless users. The communication system 100 can enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 can utilize one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), quadrature FDMA (OFDMA), and single-carrier FDMA (SC-FDMA).

[0014] As shown in Figure 1, the communication system 100 may include radio transceiver units (WTRUs) 102a, 102b, 102c, 102d, radio access networks (RANs) 103 / 104 / 105, core networks 106 / 107 / 109, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, but it will be understood that the disclosed embodiments intend any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d can be any type of device configured to operate and / or communicate in a radio environment. For example, WTRU102a, 102b, 102c, and 102d can be configured to transmit and / or receive radio signals and may include user equipment (UEs), mobile stations, fixed or mobile subscriber units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, radio sensors, and consumer electronics. WTRU102a, 102b, 102c, and 102d are interchangeable and also referred to as UEs.

[0015] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of the base stations 114a and 114b can be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks such as the core networks 106 / 107 / 109, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be base transceiver stations (BTS), node B, enode B (or eNB), gnode B (gNB), home node B, home enode B, site controller, access point (AP), and wireless router. Although each of the base stations 114a and 114b is shown as a single element, it will be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0016] Base station 114a can be part of RAN 103 / 104 / 105, which may also include other base stations and / or network elements (not shown) such as base station controllers (BSCs), radio network controllers (RNCs), and relay nodes. Base station 114a and / or base station 114b can be configured to transmit and / or receive radio signals within a specific geographic area, sometimes referred to as a cell (not shown). A cell can be further divided into cell sectors. For example, a cell associated with base station 114a can be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, for example, one per sector of the cell. In another embodiment, base station 114a may utilize multiple input multiple output (MIMO) technology, and may utilize multiple transceivers per sector of the cell.

[0017] Base stations 114a and 114b can communicate with one or more WTRUs 102a, 102b, 102c, and 102d over air interfaces 115 / 116 / 117, where air interfaces 115 / 116 / 117 can be any suitable radio communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interfaces 115 / 116 / 117 can be established using any suitable radio access technology (RAT).

[0018] More specifically, as mentioned above, the communication system 100 can be a multiple access system and can utilize one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, base stations 114a and WTRU 102a, 102b, 102c in RAN 103 / 104 / 105 can implement radio technologies such as Universal Mobile Communications System (UMTS) Terrestrial Radio Access (UTRA), which can establish air interfaces 115 / 116 / 117 using broadband CDMA (WCDMA). WCDMA can include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0019] In another embodiment, base stations 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as Advanced UMTS Terrestrial Radio Access (E-UTRA), which can establish air interfaces 115 / 116 / 117 using Long-Term Evolution (LTE) and / or LTE Advanced (LTE-A).

[0020] In other embodiments, base stations 114a and WTRUs 102a, 102b, and 102c can implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity: WiFi), IEEE 802.16 (i.e., Global Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), High-Speed ​​Data Rate for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0021] The base station 114b in Figure 1 can be, for example, a wireless router, home node B, home e-node B, or access point, and can utilize any suitable RAT to facilitate wireless connectivity in localized areas such as workplaces, homes, vehicles, and campuses. In one embodiment, the base station 114b and WTRU 102c, 102d can establish a wireless local area network (WLAN) by implementing wireless technologies such as IEEE 802.11. In another embodiment, the base station 114b and WTRU 102c, 102d can establish a wireless personal area network (WPAN) by implementing wireless technologies such as IEEE 802.15. In yet another embodiment, the base station 114b and WTRU 102c, 102d can establish a picocell or femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.). As shown in Figure 1, the base station 114b may have a direct connection to the internet 110. Therefore, base station 114b may not need to access the internet 110 via the core network 106 / 107 / 109.

[0022] RAN103 / 104 / 105 can communicate with core networks 106 / 107 / 109, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRU102a, 102b, 102c, and 102d. For example, core networks 106 / 107 / 109 can provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in Figure 1, it will be understood that RAN103 / 104 / 105 and / or core networks 106 / 107 / 109 can communicate directly or indirectly with other RANs that utilize the same RAT or a different RAT as RAN103 / 104 / 105. For example, in addition to connecting to RANs 103 / 104 / 105 which can utilize E-UTRA radio technology, core networks 106 / 107 / 109 can also communicate with other RANs (not shown) that utilize GSM, UMTS, CDMA 2000, WiMAX, or WiFi radio technology. Core networks 106 / 107 / 109 can be used as any one or any combination of, for example, (1) a 5G-enabled core network, (2) a 4G-enabled core network, (3) a 3G-enabled core network, (4) a 2G-enabled core network, (5) an LTE-A-enabled core network, (6) an LTE-enabled core network, (7) a GERAN-enabled core network, (8) a UTRAN-enabled core network, and / or (9) a UMTS-enabled core network.

[0023] Core networks 106 / 107 / 109 can also serve as gateways for WTRUs 102a, 102b, 102c, and 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing basic telephone services (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) within the TCP / IP Internet Protocol Suite. Networks 112 may include wired and / or wireless networks owned and / or operated by other service providers. For example, network 112 may include another core network connected to one or more RANs that can utilize the same or different RATs as RAN 103 / 104 / 105.

[0024] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 can include multimode functionality (for example, WTRUs 102a, 102b, 102c, and 102d can include multiple transceivers for communicating with different radio networks on different radio links). For example, WTRU 102c shown in Figure 1 can be configured to communicate with base station 114a which can utilize cellular-based radio technology, and also with base station 114b which can utilize IEEE 802 radio technology. Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 can communicate with other devices using Bluetooth technology.

[0025] Figure 2 is a system diagram showing an exemplary WTRU 102. As shown in Figure 2, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and other peripherals 138. It will be understood that the WTRU 102 may include any subcombinations of the above elements while maintaining consistency with the embodiment.

[0026] The processor 118 can be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors working with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), and a state machine, etc. The processor 118 can perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to the transceiver 120, and the transceiver 120 can be coupled to the transmit / receive element 122. Although Figure 2 shows the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0027] The transmit / receive element 122 can be configured to transmit signals to and / or receive signals from a base station (e.g., base station 114a) over the air interface 115 / 116 / 117. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In another embodiment, the transmit / receive element 122 may be a radiator / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 can be configured to transmit and / or receive any combination of radio signals.

[0028] In Figure 2, the transmit / receive element 122 is shown as a single element, but the WTRU 102 can include any number of transmit / receive elements 122. More specifically, the WTRU 102 can utilize MIMO technology. Therefore, in one embodiment, the WTRU 102 can include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and / or receiving radio signals over the air interfaces 115 / 116 / 117.

[0029] The transceiver 120 can be configured to modulate the signal to be transmitted by the transmit / receive element 122 and / or demodulate the signal received by the transmit / receive element 122. As mentioned above, the WTRU 102 can have multimode capabilities. Therefore, the transceiver 120 can include multiple transceivers to enable the WTRU 102 to communicate through multiple RATs, such as UTRA and IEEE 802.11.

[0030] The processor 118 of the WTRU102 can be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and can receive user input data from them. The processor 118 can also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 can retrieve information from any type of suitable memory, such as non-removable memory 130 and / or removable memory 132, and store data in them. Non-removable memory 130 can include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 can include subscriber identification module (SIM) cards, memory sticks, and secure digital (SD) memory cards, etc. In other embodiments, the processor 118 can obtain information from memory located on a server or home computer (not shown), which is not physically located on the WTRU 102, and can store data in it.

[0031] The processor 118 can receive power from the power supply 134 and can be configured to distribute and / or control power to other components within the WTRU 102. The power supply 134 can be any suitable device for supplying power to the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), a solar cell, and a fuel cell.

[0032] The processor 118 can be coupled to a GPS chipset 136, which can be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, the information from the GPS chipset 136, the WTRU 102 can receive location information from base stations (e.g., base stations 114a, 114b) over air interfaces 115 / 116 / 117 and / or determine its own location based on the timing of signals received from two or more nearby base stations. It will be understood that the WTRU 102 can acquire location information using any suitable location determination method while maintaining consistency with the embodiments.

[0033] The processor 118 can be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos and / or videos), a Universal Serial Bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, and an internet browser.

[0034] WTRU102 may include a full-duplex radio in which some or all of the transmission and reception of signals (e.g., associated with specific subframes for both uplink UL (e.g., for transmission) and downlink DL (e.g., for reception) can be in parallel and / or simultaneously, for example, partially or completely. The radio (e.g., a full-duplex radio) may include an interference management unit 139 to reduce and / or substantially eliminate SINFT, either through hardware (e.g., chokes) or through signal processing via a processor (e.g., a separate processor (not shown) or processor 118).

[0035] Figure 3 is a system diagram showing RAN103 and core network 106 according to another embodiment. As mentioned above, RAN103 can communicate with WTRU102a, 102b, and 102c over air interface 115 using UTRA radio technology. RAN103 can also communicate with core network 106. As shown in Figure 3, RAN103 may include nodes B140a, 140b, and 140c, each of which may include one or more transceivers for communicating with WTRU102a, 102b, and 102c over air interface 115. Each of nodes B140a, 140b, and 140c may be associated with a specific cell (not shown) within RAN103. RAN103 may also include RNC142a and 142b. It will be understood that RAN103 can include any number of nodes B and RNC while maintaining consistency with the embodiment.

[0036] As shown in Figure 3, nodes B140a and B140b can communicate with RNC142a. In addition, node B140c can communicate with RNC142b. Nodes B140a, B140b, and B140c can communicate with each other via the Iub interface. RNC142a and B142b can communicate with each other via the Iur interface. Each of RNC142a and B142b can be configured to control each of the nodes B140a, B140b, and B140c to which it is connected. In addition, each of RNC142a and B142b can be configured to implement or support other functionalities such as outer loop power control, load control, admission control, packet scheduling, handover control, macro diversity, security functions, and data encryption.

[0037] The core network 106 shown in Figure 3 may include a media gateway (MGW) 144, a mobile switching center (MSC) 146, a serving GPRS support node (SGSN) 148, and / or a gateway GPRS support node (GGSN) 150. Although each of the above elements is shown as part of the core network 106, it will be understood that any one of these elements may be owned and / or operated by an entity different from the core network operator.

[0038] The RNC142a in RAN103 can connect to the MSC146 in the core network 106 via the IuCS interface. The MSC146 can connect to the MGW144. The MSC146 and MGW144 provide access to circuit-switched networks such as PSTN108 to WTRU102a, 102b, and 102c, facilitating communication between WTRU102a, 102b, and 102c and conventional fixed telephone line communication devices.

[0039] RNC142a in RAN103 can also connect to SGSN148 in core network 106 via the IuPS interface. SGSN148 can connect to GGSN150. SGSN148 and GGSN150 provide WTRU102a, 102b, and 102c with access to packet-switched networks such as the Internet 110, facilitating communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0040] As mentioned above, the core network 106 may also connect to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0041] Figure 4 is a system diagram showing RAN 104 and core network 107 according to an embodiment. As mentioned above, RAN 104 can utilize E-UTRA radio technology to communicate with WTRU 102a, 102b, and 102c over air interface 116. RAN 104 can also communicate with core network 107.

[0042] RAN104 may include e-nodes B160a, 160b, and 160c, but it will be understood that RAN104 may include any number of e-nodes B while maintaining consistency with the embodiment. Each of the e-nodes B160a, 160b, and 160c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c over the air interface 116. In one embodiment, e-nodes B160a, 160b, and 160c can implement MIMO technology. Thus, e-node B160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU102a.

[0043] Each of the e-nodes B160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, and user scheduling in UL and / or DL. As shown in Figure 4, the e-nodes B160a, 160b, and 160c can communicate with each other over the X2 interface. The e-nodes B may include full-duplex radios similar to those of the WTRU (e.g., with interference management units). The core network 107 shown in Figure 4 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the above elements is shown as part of the core network 107, it will be understood that any of these elements may be owned and / or operated by an entity different from the core network operator.

[0044] The MME162 can connect to each of the e-nodes B160a, 160b, and 160c within RAN104 via the S1 interface and can act as a control node. For example, the MME162 can be responsible for user authentication of WTRU102a, 102b, and 102c, bearer activation / deactivation, and selection of a specific serving gateway during the initial connection of WTRU102a, 102b, and 102c. The MME162 can provide control plane functionality for exchanges between RAN104 and other RANs (not shown) utilizing other radio technologies such as GSM and / or WCDMA.

[0045] The serving gateway 164 can connect to each of the e-nodes B160a, 160b, and 160c in RAN104 via the S1 interface. The serving gateway 164 can generally route and forward user data packets to and from WTRU102a, 102b, and 102c. The serving gateway 164 can perform other functions such as anchoring the user plane during e-node B handover, triggering paging when DL data is available to WTRU102a, 102b, and 102c, and managing and remembering the context of WTRU102a, 102b, and 102c.

[0046] The serving gateway 164 can connect to the PDN gateway 166, which provides WTRUs 102a, 102b, and 102c with access to a packet-switched network such as the Internet 110, thereby facilitating communication between WTRUs 102a, 102b, and 102c and IP-enabled devices.

[0047] The core network 107 can facilitate communication with other networks. For example, the core network 107 can provide WTRU 102a, 102b, and 102c with access to a circuit-switched network such as PSTN 108, thereby facilitating communication between WTRU 102a, 102b, and 102c and conventional fixed-line communication devices. For example, the core network 107 may include, or communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the core network 107 and PSTN 108. In addition, the core network 107 can provide WTRU 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0048] Figure 5 is a system diagram showing RAN105 and core network 109 according to an embodiment. RAN105 can be an access service network (ASN) that communicates with WTRU102a, 102b, and 102c over air interface 117 using IEEE 802.16 wireless technology. As will be further described below, communication links between different functional entities of WTRU102a, 102b, 102c, RAN105, and core network 109 can be defined as reference points.

[0049] As shown in Figure 5, RAN105 may include base stations 180a, 180b, 180c and an ASN gateway 182, but it will be understood that RAN105 may include any number of base stations and ASN gateways while maintaining consistency with the embodiment. Each of the base stations 180a, 180b, 180c may be associated with a specific cell (not shown) within RAN105, and each may include one or more transceivers for communicating with WTRU102a, 102b, 102c over the air interface 117. In one embodiment, the base stations 180a, 180b, 180c may implement MIMO technology. Base station 180a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU102a. Base stations 180a, 180b, and 180c can also provide mobility management functions such as handoff triggering, tunnel establishment, radio resource management, traffic classification, and quality of service (QoS) policy enforcement. The ASN gateway 182 can act as a traffic aggregation point and is responsible for paging, subscriber profile caching, and routing to the core network 109.

[0050] The air interface 117 between WTRU102a, 102b, 102c and RAN105 can be defined as the R1 reference point, implementing the IEEE 802.16 specification. In addition, each of WTRU102a, 102b, and 102c can establish a logical interface (not shown) with the core network 109. The logical interface between WTRU102a, 102b, 102c and the core network 109 can be defined as the R2 reference point, which can be used for authentication, authorization, IP host configuration management, and / or mobility management.

[0051] The communication links between base stations 180a, 180b, and 180c can be defined as R8 reference points, which include protocols to facilitate WTRU handover and data transfer between base stations. The communication links between base stations 180a, 180b, and 180c and the ASN gateway 182 can be defined as R6 reference points. The R6 reference points may include protocols to facilitate mobility management based on mobility events associated with each of WTRU 102a, 102b, and 102c.

[0052] As shown in Figure 5, RAN 105 can connect to core network 109. The communication link between RAN 105 and core network 109 can be defined as an R3 reference point, which includes, for example, protocols to facilitate data transfer and mobility management functions. Core network 109 may include a Mobile IP Home Agent (MIP-HA) 184, an Authentication Authorization and Billing (AAA) server 186, and a gateway 188. Although each of the above elements is shown as part of core network 109, it will be understood that any of these elements may be owned and / or operated by an entity different from the core network operator.

[0053] The MIP-HA184 can handle IP address management and enable WTRU102a, 102b, and 102c to roam between different ASNs and / or different core networks. The MIP-HA184 can provide WTRU102a, 102b, and 102c with access to packet-switched networks such as the Internet 110, facilitating communication between WTRU102a, 102b, and 102c and IP-enabled devices. The AAA server 186 can handle user authentication and support user services. The gateway 188 can facilitate interworking with other networks. For example, the gateway 188 can provide WTRU102a, 102b, and 102c with access to circuit-switched networks such as the PSTN 108, facilitating communication between WTRU102a, 102b, and 102c and traditional fixed-line communication devices. Gateway 188 can provide access to other networks 112 to WTRU 102a, 102b, and 102c, and network 112 may include other wired and / or wireless networks owned and / or operated by other service providers.

[0054] Although not shown in Figure 5, it will be understood that RAN105 can connect to other ASNs, and other RANs (e.g., RAN103 and / or 104) and / or core network 109 can connect to other core networks (e.g., core networks 106 and / or 107). The communication link between RAN105 and other ASNs can be defined as an R4 reference point, and the R4 reference point may include protocols for coordinating the mobility of WTRU102a, 102b, and / or 102c between RAN105 and other ASNs. The communication link between core network 109 and other core networks can be defined as an R5 reference point, and the R5 reference may include protocols for facilitating interworking between the home core network and the area core network.

[0055] In Figures 1 to 5, the WTRU was described as a wireless terminal, but in a typical embodiment, such a terminal is intended to be able to use a wired communication interface with a communication network (e.g., temporarily or permanently).

[0056] In a typical embodiment, methods, apparatus, and / or systems for New Radio (NR) can be implemented, which may utilize channel reciprocity. Processes and / or procedures enabling channel reciprocity-based UL MIMO (e.g., for time-division duplexing (TDD)) may include partial reciprocity and / or full reciprocity.

[0057] For example, certain typical operations, procedures, and / or methods may, among others, use (1) UL angular reciprocity, (2) AI avoidance for MIMO (e.g., UL MIMO and / or DL ​​MIMO), (3) UL multi-user (MU)-MIMO based on interference feedback (e.g., (i) single spatial stream transmission and single codebook, (ii) multi-spatial stream transmission with a single codebook, and / or (iii) multi-spatial stream transmission with a double codebook), (4) UL MU-MIMO based on a precoded sounding reference signal (SRS), (5) UL beamformed reciprocity, (6) DL channel measurement using asymmetric interference in WTRU, (7) UL channel reciprocity beamforming via or using a codebook, (8) an access point (AP) (e.g., eNB, gNB, or other AP) to disable WTRU autonomous UL precoding decisions, (9) WTRU calibration display, and / or (10) beamformed transmit diversity.

[0058] While most embodiments relate to UL MIMO, those skilled in the art will understand that some embodiments may also relate to large-scale MIMO, which may include beamforming operations.

[0059] In LTE systems, DL channel reciprocity is used. For example, a base station (BS) can acquire channel information through UL sounding reference signal transmission and apply this channel information to precode DL data and / or control transmissions (e.g., beamforming). In the case of large antenna array systems, a channel reciprocity-based scheme can result in a reduction of feedback overhead (e.g., a significant reduction) and can be used in practical deployments (e.g., can be appropriate). For next-generation mobile communication systems, it is intended that TDD can be the primary operating mode and that large antenna array systems can be used for high-frequency bands. The use of channel reciprocity can enable (e.g., can be key to the success of) wireless communication systems (e.g., future wireless communication systems).

[0060] In a typical embodiment, a large number of antenna elements (e.g., sets and / or arrays) (e.g., more than a threshold) can be implemented on the WTRU side for certain frequency bands (e.g., intermediate and / or higher frequency bands (e.g., above a threshold)). For example, at higher frequencies, the size and / or complexity of the antenna can be reduced. For next-generation mobile communication systems, the WTRU is intended to be able to operate in higher frequency bands, and for example, a large antenna array can be used on the WTRU side to enable beamforming in UL. In a typical embodiment, channel reciprocity can be implemented, for example, to estimate UL channel state information (CSI).

[0061] New Radio (NR) networks can implement WTRU-based multiple transmissions. For example, WTRU-based multiple transmissions can include gNB-assisted WTRU MIMO, gNB-driven WTRU MIMO, and / or gNB-directed WTRU MIMO.

[0062] For example, in gNB-driven WTRU MIMO, the gNB can control the WTRU MIMO scheme / operation / procedure. The gNB can identify a number of antenna schemes and antenna weights that the WTRU should use for MIMO transmission. For example, typical schemes / operations / procedures may include any of the following: (26) The WTRU can transmit multidimensional SRS to the gNB (for example, in the case of analog beam-based design / operation for higher frequency transmission and / or digital beamformed design / operation, the dimensions may be based on the WTRU's transmitting antenna and / or the WTRU's effective transmitting beam). (27) gNB can estimate the effective uplink MIMO channel and / or the best precoder based on SRS. (28) gNB may indicate and / or include in messages sent to the WTRU (e.g., signaling) (e.g., on a downlink control channel, in a UL grant, and / or in other control signaling) a precoder used by the WTRU (e.g., a precoder may be indicated by sending the WTRU a codeword and / or precoding / beamforming matrix index (PMI) belonging to a codebook (e.g., a well-designed codebook); a precoder may be included by explicitly sending the precoder used by the WTRU). and / or (29) The WTRU may transmit information to the gNB using the indicated or included precoder.

[0063] gNB-driven WTRU MIMO can be adapted to generalized UL MU MIMO and may or may not restrict WTRUs to single-stream transmission. For example, in one typical embodiment, the gNB may select a WTRU MIMO precoder to limit and / or reduce interference among multiple UL WTRUs.

[0064] In autonomous WTRU MIMO and / or WTRU-directed MIMO, the WTRU can autonomously determine and / or decide on a number of antenna schemes and antenna weights that the WTRU can use for MIMO (e.g., UL MIMO) transmission. For example, in this case, the WTRU may need to know the channel and / or be able to determine the channel (e.g., channel estimation). The WTRU may have a channel (e.g., channel estimation) that is supplied to it (e.g., forwarded to it as feedback) by the gNB (and / or another network entity) based on the UL multidimensional SRS transmitted by the WTRU. The WTRU can derive a precoder using the estimated channel and / or transmit information to the gNB (e.g., using the estimated channel information / derivated precoder information).

[0065] The use of UL beamforming for next-generation mobile communication systems can enhance system performance and have minimal impact on control and feedback signaling. A typical embodiment may include devices, operations, procedures, and / or methods that can be used to enhance the reciprocity characteristics of a channel (e.g., a communication channel) to improve performance in the user plane and / or control plane. Support mechanisms may be used with certain channel reciprocity operations, procedures, and / or methods to mitigate secondary problems associated with channel reciprocity, such as asymmetric interference and / or measurement inaccuracies.

[0066] The effectiveness of channel reciprocity may depend on any of the following: (1) channel time coherence, (2) channel frequency coherence, (3) interference at the transmitter, and / or (4) interference at the receiver. The source of interference in the DL at a WTRU receiver (e.g., the primary source) may be a neighboring base station, and the source of interference in the UL at a base station (e.g., the primary source) may be inter-cell and intra-cell WTRUs. DL channel information may not be used by the WTRU as an estimate of the channel for the UL (e.g., not directly), and vice versa (e.g., UL channel information may not be used by the base station as an estimate of the channel for the DL (e.g., not directly)).

[0067] In conventional systems using MU-MIMO operating modes within a UL, the base station can transmit precoding vectors to the WTRU, for example, to maintain good orthogonality between transmissions from the WTRU. In a typical embodiment, in the case of UL channel reciprocity, the WTRU can determine its UL beamforming / precoding vector / matrix (e.g., autonomously, without network control). In the case of MU-MIMO, suitable equipment, operation, and / or procedures can be used (e.g., to ensure that a number of simultaneously scheduled WTRUs do not interfere with each other at the base station receiver).

[0068] Typical procedure for UL complete channel reciprocity For example, beamforming in the mmW band in the range between approximately 30 GHz and 300 GHz can, among other things, use (1) a feedback (e.g., precise feedback) procedure and / or (2) a codebook (e.g., an efficiently designed codebook). A mobile unit, e.g., a WTRU, can be equipped with a number of antennas, e.g., for smaller (e.g., very small) sizes of antennas, e.g., using mm waves (e.g., higher frequency bands) or operating in mm waves. Typical implementations include cross-polarized or correlated N H ×N VIt can be based on an antenna array system (H and V represent horizontal and vertical polarization). Implementations based on other types of polarization (such as circular polarization) can also be used. As the number of antennas increases, a codebook with more elements can be used (for example, a codebook with more elements may be appropriate to facilitate channel-based, for example, precise beamforming). In a typical embodiment, for example, a large codebook implementation (e.g., the need for a larger codebook and / or a codebook with a threshold number of elements), as well as to eliminate or substantially reduce large feedback overhead (e.g., associated with the transmission of codebook values ​​between the transmitter and receiver), the UL channel can be estimated using channel reciprocity. The UL channel is derived from the observed DL channel.

[0069]

number

[0070] This can be estimated (for example, directly) and used for UL beamformer design.

[0071] In real-world systems, the accuracy of DL measurements can be reduced and / or limited by a number of factors, including (1) noise, (2) UL / DL asymmetric interference, and / or (3) hardware malfunctions. In one typical embodiment, beamforming is estimated.

[0072]

number

[0073] The covariance matrix

[0074]

number

[0075] This can be based on statistical measures such as those mentioned above.

[0076] In FDD-based systems, for example, the DL covariance matrix is ​​intended to be used for UL beamforming, provided that the frequency difference between UL and DL is within a threshold (e.g., not significant enough to cause a large difference in channel characteristics), or as long as this condition is met. In cases where some difference may exist, a linear or nonlinear transformation of the DL channel can be used to estimate the UL channel.

[0077] The advantages of UL channel reciprocity may include any of the following: (1) reduced control signaling overhead in DL; (2) the ability of the base station not to transmit (e.g., not to transmit) a precoding matrix for UL to the WTRU; (3) reduced sounding reference symbol overhead in UL, for example, used by the base station for UL channel estimation; or (4) reduced channel aging (e.g., channel aging problem), for example, due to reduced latency of UL CSI from the base station.

[0078] Representative procedure for UL partial channel reciprocity In a typical embodiment, a typical precoder can be implemented based on, for example, a precoder design scheme for UL MIMO (to enable UL reciprocity in a scenario where partial channel information is available in the WTRU). In a typical embodiment, feedback on partial channel information, which may otherwise be transmitted by the eNB, is eliminated and / or substantially reduced. The precoder scheme can be based on a multiple codebook precoder structure, for example, as a method for supporting the implementation of beamforming using multiple antennas or (e.g., a large number of) antenna arrays for UL transmission. In a typical embodiment, other codebook precoding structures can be used, including higher-order structures, e.g., (1) a double codebook precoding structure and / or (2) a triple codebook precoding structure, among others. Those skilled in the art will understand that precoding using and / or including three or more codebooks can be implemented similarly. A beamformed signal transmitted from one WTRU to a network access point (e.g., e-node B (eNB) or other access point) can be expressed by Equation 1 as follows: y = W1W2x (1) Here, W1 is the first beamforming matrix, W2 is the second beamforming matrix, and x is the transmitted data symbol vector from the WTRU. To reduce control overhead (e.g., appropriate and / or required control overhead), the derivation mechanism and selection process for W1 and W2 are divided into two parts, the WTRU command part and the eNB command part, respectively. W1: WTRU drive W2: eNB drive It can be divided into, where (1) the WTRU-driven beamformer W1 can track (1) low-rate channel fluctuations in either time and / or frequency, and (2) the eNB-driven beamformer W2 can enable short-term correction. The eNB (e.g., a network access point or network entity) can instruct the WTRU in the selection of W2, and W1 can be determined and / or decided by the WTRU itself (e.g., the decision of W1 may not be under the control of the eNB).

[0079] In one typical embodiment, the role of the beamformer is interchangeable, and W1 is intended to be determined and / or set by the eNB, and W2 is intended to be determined and / or set by the WTRU.

[0080] When using rank information, the WTRU procedure for UL beamforming may include one of the following actions: (1) WTRU can estimate the UL channel based on one or more DL measurements (e.g.,

[0081]

number

[0082] ). For example, DL channel information can be derived, among other things, from DL reference symbols (e.g., specifically used for channel estimation) and / or from demodulation reference symbols embedded within DL data / control transmissions. The function F above shows that DL channels can be transformed by the function to improve UL channel estimation. In a typical embodiment, this function can be a linear transformation (or the identity matrix if no transformation is appropriate and / or required) or a nonlinear transformation of any order. (2) WTRU can determine the precoding / beamforming matrix / vector W1 based on channel-related measurements. For example, the precoding matrix W1 is estimated

[0083]

number

[0084] The precoding matrix W1 can be derived from, or the precoding matrix W1 can be determined based on all or a subset of the eigenvectors of its covariance matrix R. The WTRU can transmit the precoding matrix / vector W1 to the eNB to enable the eNB to estimate the precoding / beamforming matrix / vector W2. As an example, in one procedure (e.g., an implicit procedure), the WTRU can send a precoded reference signal to the eNB, and the eNB can estimate the precoding matrix / vector W2 based on the precoded reference signal. As a second example, in a second procedure (e.g., an explicit procedure), the WTRU can feed back or provide a representation of the precoding matrix / vector W1 to the eNB. The representation can be one or more of the following: (i) PMI values ​​representing W1, (ii) a compressed explicit set of values ​​for the precoding matrix / vector W1, or (iii) differential PMI / vectors showing the difference between vectors previously sent to the eNB by the WTRU (e.g., over time and / or frequency). The eNB can infer the precoding matrix / vector W1 based on rules agreed upon between the WTRU and the eNB. The rules can take long-term channel statistics as input and generate the precoding / beamforming matrix / vector. The WTRU can determine the precoding / beamforming matrix / vector W1 based on the rules and estimations of the UL channel (e.g., using channel reciprocity), and the eNB can infer the precoding / beamforming matrix / vector W1 based on the same rules and actual measurements of the UL channel. (3) The WTRU can monitor the DL control channel, decode the associated payload, and / or determine the precoding / beamforming matrix index (PMI) with respect to the precoding matrix / vector W2. For example, the decoded PMI can provide further updates on the channel direction to improve beamforming accuracy.

[0085]

number

[0086] Since the precoding matrix / vector W2 can become outdated, it can be used as a correction to improve the overall precoder match for the current channel. The WTRU can identify the precoding matrix / vector W2 beamforming matrix explicitly or implicitly from the decoded PMI. (4) The WTRU can beamform the transmitted data vector as y = W1W2x.

[0087] Typical Procedure for UL Angle Reciprocity In one typical embodiment, the reciprocity between the DL arrival angle (AOA) and the UL emission angle (AOD) can be used for a WTRU that utilizes or uses a certain type of beamforming (e.g., hybrid beamforming, where the WTRU can use a combination of analog and digital beamforming). For example, the WTRU can measure the AOA of the signal at DL and use the measured AOA to determine the beamforming vector for UL transmission. The UL and DL antenna responses for a uniform linear array ULA can be given by Equation 2 below.

[0088]

number

[0089] Here, f0 is the carrier frequency for which the ULA was designed, Δ is the antenna spacing (in wavelengths) at that frequency (e.g., at the f0 carrier frequency), and θ is AOA / AOD.

[0090] The UL and DL antenna responses can be related as given by Equation 3, a UL (θ)=T(θ)a DL (θ) (3) where the transformation matrix T(θ) is given by the following Equation 4.

[0091]

Number

[0092] f DL =f UL In the case of the TDD operation mode, where is, the transformation matrix T(θ) can be simplified to the identity matrix, as given by, for example, Equation 5. a UL (θ)=a DL (θ) (b) (5)

[0093] In one representative embodiment, the WTRU can use the array response vector a UL (θ) as W1 in a representative procedure for partial channel reciprocity described herein. For example, W2 can be transmitted by the base station. In one representative embodiment, a UL (θ) can be utilized in the analog domain to maximize the beamforming gain in the direction of the base station and W2 can be utilized in the digital domain (e.g., to maximize the signal-to-noise ratio (SNR) and / or minimize interference from other WTRUs), and according to one embodiment, the AOA can be the elevation and azimuth (EA) AOA and / or the AOD can be the EA AOD.

[0094] Representative Procedures for Asymmetric Interference (AI) Avoidance for UL MIMO FIG. 6 is a diagram illustrating a representative procedure for AI avoidance for UL MIMO.

[0095] Referring to Figure 6, network 600 may include a first cell 610-1 having coverage area 615-1 and a second cell 610-2 having coverage area 615-2. AP620-1 (e.g., an eNB, gNB, and / or other radio access network (RAN) entity, sometimes referred to hereafter as AP / eNB) may service the first cell 610-1, and AP620-2 may service the second cell 610-2. A first WTRU102-1 may be within coverage area 615-1 of the first cell 610-1. A second WTRU102-2 may be within coverage area 615-2 of the second cell 610-2. WTRU102-2 may transmit and / or send interference signals (e.g., interference channel v). AP / eNB620-1 can determine precoding matrix (PM) information (e.g., PM index) based on the interference channel v, and / or transmit a signal (e.g., a desired DL signal) to WTRU102-1. For example, the desired signal can be precoded based on the interference channel v.

[0096] In one typical embodiment, the AI ​​phenomenon can arise from inter-cell interference and can cause problems (e.g., concerns regarding the use of channel reciprocity). If AP / eNB620-1 experiences interference in a particular spatial direction and / or within a particular spatial direction, WTRU102-1 may not be able to determine or know about the interference in that spatial direction based on the DL transmission of AP / eNB620-1. If WTRU102-1 can acquire UL interference information, WTRU102-1 can adapt to the UL interference to avoid transmission on and / or within the same channel direction. A beamforming matrix W, as shown in Equation 6, can be used to divert the direction of UL transmission away from interference (e.g., interfering channel v). y = Wx (6) Here, W is the beamforming matrix, x is the transmitted data symbol vector, and y is the beamformed transmitted vector.

[0097] In one typical embodiment, WTRU102 (1) estimates the UL channel based on DL measurement (e.g.,

[0098]

number

[0099] (1) (2) monitoring the DL control channel; (3) decoding the associated payload; (4) determining the PMI regarding the direction of the interference channel v (sometimes shown as v); (5) estimating the precoding / beamforming matrix / vector W based on the estimated channel and interference channel v, such that the interference channel v lies in the null space of the precoding / beamforming matrix / vector W, or that the precoding / beamforming matrix / vector W and the interference channel v are (e.g., W⊥v); and / or (6) beamforming the transmitted data vector as y=Wx.

[0100] In one typical embodiment, WTRU102 can estimate the precoding / beamforming matrix / vector W (e.g., based on the estimated channel) and the interfering channel v such that the precoding / beamforming matrix / vector W minimizes a metric associated with the mean squared error (MSE). For example, the MSE criterion may be: (i) the sum of the MSE of the serving AP / eNB620 and the interference in channel v, e.g., MSE + α Interference, where α is a well-chosen parameter; and / or (ii) the larger of the minimized MSE and the interference in channel v, e.g., to minimize the larger of (MSE, Interference). In one typical embodiment, the MSE criterion can be used with (e.g., with only) statistical knowledge about the interfering channel v.

[0101] Typical Procedures for UL MU-MIMO Based on Interference Feedback Typical procedures can be implemented to reduce inter-user interference using the minimum requirements for AP / eNB feedback for UL MU-MIMO communications. In certain communications (e.g., LTE, LTE-A, nuRadio, and other communications beyond or different from LTE, LTE-A, and nuRadio), a number of WTRU102s (e.g., multiple WTRU102s or clusters of WTRU102s) can be paired (e.g., transparently) to transmit on the same frequency-time resource. The AP / eNB620 can assign a PMI to each of the WTRU102s, several WTRU102s, or multiple WTRU102s to orthogonalize their UL transmissions. Due to the limited granularity of the PMI, performance may be reduced and / or limited.

[0102] To improve UL MIMO performance, the WTRU102 can derive an estimate of the direction of UL beamforming / precoding depending on channel reciprocity and can receive assistance from the AP / eNB620 to attempt to orthogonalize its transmission with respect to other WTRU102s in the cluster. The WTRU102 can use, for example, (1) single spatial stream transmission and single codebook, (2) multi-spatial stream transmission with a single codebook, and / or (3) multi-spatial stream transmission with a higher-order codebook (e.g., double codebook, triple codebook, or even higher-order codebook). For example, in one typical embodiment, each WTRU102 can transmit a single spatial stream (e.g., just one spatial stream) such that consecutive transmissions are in the same or substantially the same direction (e.g., on the same channel or substantially within the same channel), and the precoding codebook can be a single codebook. In other typical embodiments, the WTRU102 can transmit multiple spatial streams, and the pre-coding codebook can be a single codebook or a higher-order codebook (e.g., a double or triple codebook, among others).

[0103] Typical procedure using single spatial stream transmission and single codebook Figure 7 shows a typical procedure using single spatial stream transmission and a single codebook. Referring to Figure 7, a typical procedure 700 can include two or more WTRU102s (e.g., two user devices, or WTRU102-1, 102-2) and an AP / eNB620. One or each of WTRU102-1 and / or WTRU102-2 can receive advice on interference directions v1 and v2 by different PMIs that reflect and / or indicate interference directions v1 and v2.

[0104] A typical procedure (e.g., the overall procedure) may include any of the following: (1) WTRU102-1 can estimate the UL channel based on DL measurements (e.g.,

[0105]

number

[0106] (2) WTRU102-1 can monitor the DL control channel. (3) WTRU102-1 can decode the associated payload. (4) WTRU102-1 can determine the PMI with respect to interference direction v (e.g., interference direction v2). For example, interference direction can be the direction of transmission by other users within the MU-MIMO cluster. (e.g., vector v can represent the interference direction of one WTRU102-2 (e.g., just one interference WTRU102-2) or the aggregated interference direction.) (5) WTRU102-1 can estimate the precoding / beamforming matrix / vector W based on the estimated channel and interference channel / direction v, such that the interference channel / direction v can be in the null space of the precoding / beamforming matrix / vector W, or such that the precoding / beamforming matrix / vector W and interference channel v are (e.g., W⊥v). Furthermore / or (6)WTRU102-1 can beamform the transmitted data vector as y=Wx.

[0107] In one typical embodiment, WTRU102 can estimate the precoding / beamforming matrix / vector W (e.g., based on the estimated channel) and the interference channel / direction v such that the precoding / beamforming matrix / vector W can minimize a metric associated with the mean squared error (MSE). For example, the MSE criterion may be: (i) MSE and channel v of the serving AP / eNB620. iThe sum with interference in, for example, MSE + Σα i Interference i And here, α i (ii) is a well-selected parameter, and / or (ii) for example, to minimize the larger of (MSE, Interference), the minimized MSE and channel v i The larger of the interferences in the given region. In one typical embodiment, the MSE criterion can be used in conjunction with (for example, with) statistical knowledge about the interference channel / direction v.

[0108] Typical procedure for using multi-space stream transmission with a single codebook Figure 8 shows a typical procedure using multi-spatial stream transmission and a single codebook. Referring to Figure 8, a typical procedure 800 can use any number of AP / eNB620s (e.g., gNB, eNB, and / or RAN entities) and any number of WTRU102s (e.g., WTRU102-1, 102-2, 102-3...102-K). UL MU-MIMO can have multi-spatial stream transmission based on interference feedback. The AP / eNB620 can adjust the precoding / beamforming matrix selection in the WTRU102 for UL MU-MIMO transmission so that mutual interference can be reduced, for example. In one typical embodiment, when K WTRUs 102-1, 102-2, 102-3...102-K (where K is a positive integer) are simultaneously transmitting to a single AP / eNB620, a procedure can be implemented to enable the first WTRU 102-1 among the K WTRUs 102-1, 102-2, 102-3...102-K to autonomously determine its own precoding / beamforming matrix that minimizes interference from the other K-1 WTRUs 102-2, 102-3...102-K. From the perspective of the first WTRU 102-1, the other WTRUs (e.g., WTRU 102-2, 102-3...WTRU 102-K) can be considered as a single equivalent WTRU 102-2' for the sake of simplification of notation.

[0109] The received signal in AP / eNB620 can be as given by Equation 7 below.

[0110]

number

[0111] Singular value decomposition (SVD) of a channel matrix is,

[0112]

number

[0113] i can be set to 1 or 2. For example, given a precoding / beamforming matrix / vector W2, (e.g., known and / or determined), WTRU102-1 can determine its precoding matrix with the help of AP / eNB620.

[0114] As a first typical procedure, when AP / eNB620 transmits a quantized or unquantized version of H2W2 to WTRU102-1, WTRU102-1 can select and / or determine its precoding / beamforming matrix W1 such that the column space H1W1 is orthogonal to the column space of H2W2, and AP / eNB620 can separate the two signals by projecting the received signal vectors separately into the two orthogonal column spaces (e.g., they can be easily separated). The precoding / beamforming matrix W1 thus selected and V1 in SVD are intended to be identical, but may not be identical, in conventional LTE / LTE-A systems. WTRU102-1 can know or determine the channel matrix H1 through explicit (and / or implicit) feedback from AP / eNB620 or by using channel reciprocity.

[0115] As a second typical procedure, AP / eNB620 can select and / or determine column i in the column space H2W2 having the largest norm and send i to WTRU102-1. WTRU102-1 can attempt and / or attempt to avoid using the direction represented by i. For example, WTRU102-1 can communicate a vector instead of a matrix, for example, (1) (2) In order to significantly reduce signaling overhead and to avoid parts of mutual interference (e.g., significant parts), the precoding / beamforming matrix W1 can be selected and / or determined such that the column space of H1W1 does not contain i.

[0116] As a third typical procedure, AP / eNB620 can select and / or determine column i of the column space H2W2 having the smallest norm and send i to WTRU102-1. WTRU102-1 can attempt and / or attempt to use the direction represented by i. For example, WTRU102-1 can select and / or determine a precoding / beamforming matrix W1 such that the column space H1W1 can contain i.

[0117] Typical procedure for using multi-space stream transmission with a double codebook The precoding / beamforming matrix may consist of, for example, two parts, or may include two parts. The first part may capture (e.g., indicate and / or track) the long-term and / or broadband behavior of the channel, and the second part may capture (e.g., indicate and / or track) the short-term and / or narrowband behavior of the channel. The signal received in AP / eNB620 can be given by the following equation 8:

[0118]

number

[0119] Here, LT represents long-term and ST represents short-term. The precoding / beamforming matrix can contain two parts, but any number of parts is possible. This issue, associated with dual codebooks for interference management / reduction, is related to new channels.

[0120]

number

[0121] If defined, it can be simplified to a single codebook problem. For example, a new channel is G i This allows us to have a new precoding matrix,

[0122]

number

[0123] This can be done. To solve this problem, the solution for the single codebook case can be used. The network operation may include any of the following: (1) AP / eNB620 is

[0124]

number

[0125] The following is sent to WTRU102-1, which then receives the ST precoding / beamforming matrix.

[0126]

number

[0127] (For example, the best or optimal)

[0128]

number

[0129] ) determines (e.g., ST precoding / beamforming matrix)

[0130]

number

[0131] (2) AP / eNB620 is,

[0132]

number

[0133] This can be sent to WTRU102-1, which then receives the LT precoding / beamforming matrix.

[0134]

number

[0135] (For example, the best or optimal)

[0136]

number

[0137] ) can be determined. ST precoding / beamforming matrix

[0138]

number

[0139] This can be obtained through feedback from AP / eNB620, and / or (3) AP / eNB620 has a specific norm (e.g., the maximum norm).

[0140]

number

[0141] The column can be sent to WTRU102-1, which will then receive the ST precoding / beamforming matrix.

[0142]

number

[0143] (For example, the best or optimal)

[0144]

number

[0145] ) can be determined. LT precoding / beamforming matrix

[0146]

number

[0147] This can be obtained through feedback from AP / eNB620 and / or by local measurements based on channel reciprocity.

[0148] Typical WTRU support and eNB-centric procedures Figure 9 shows a typical WTRU-assisted interference adjustment procedure.

[0149] Referring to Figure 9, in a multi-user environment, WTRUs (e.g., WTRU102-1 and / or WTRU102-2) can provide interference-related information to manage interference within the WTRU. A typical procedure may include one of the following: (1) WTRU102 (e.g., one or more WTRUs, or each WTRU) can estimate the UL channel using (e.g., depending on) channel reciprocity. For example, WTRU102-1 can perform DL channel measurement, which may be available from, for example, a DL reference signal (RS). In TDD, it is intended that the transpose of the estimated DL channel may be the estimate of the UL channel. For FDD, depending on the frequency difference between UL and DL or between UL and DL, the estimated DL channel may be the estimate of the UL channel with or without additional correction (e.g., in a typical embodiment, one or more additional correction factors may be appropriate and / or required). (2) Given an estimated UL channel, WTRU102-1 can select a set of precoders (e.g., one or more precoders) and communicate (e.g., provide or indicate) the set of precoders to AP / eNB620. In one typical embodiment, the set of precoders can be selected from predetermined precoders, and WTRU102 can provide one or more indices (e.g., one or more codebook values) to one or more selected predetermined precoders. The selection mechanism and / or procedure can be based on one or more performance measures, such as signal-to-noise ratio (SNR), signal-to-interference ratio (SNI), other noise measurements, and / or capacitance measurements, among other things. The selected and / or reported set of precoders can be, or include, the best and / or worst precoders for achieving one or more intended criteria. (3) AP / eNB620 may receive, store, and / or collect a reported set of precoders (and / or the display or codebook values ​​associated with the reported precoders) from one or more WTRU102s (e.g., all of WTRU102-1 and WTRU102-2 with which AP / eNB620 communicates) to analyze the interference and scheduling requirements of the WTRU102s. AP / eNB620 may include information about UL channels observed by AP / eNB620 from UL SRS signals (e.g., if available). (4) AP / eNB620 may select precoders for WTRU102 (e.g., WTRU102-1 and WTRU102-2, respectively) based on the reported set of precoders. One or more criteria (e.g., basic criteria) may be to reduce and / or minimize mutual interference for UL transmissions from a large number of WTRU102s. Provided that the reported set of precoders is the best set of precoders (e.g., based on one or more rules and / or criteria), the recommended set of precoders from WTRU102-1 is {W 1i It is sometimes called}, and the recommended precoder set from WTRU102-2 is {W 2j It is sometimes called}. AP / eNB620 is ||(H1W 1i ) † (H2W 2j i and j can be selected such that || can be minimized, substantially minimized, and / or reduced, where || can represent the Frobenius norm.

[0150] Typical procedure for UL MU-MIMO based on a precoded sounding reference signal In one typical embodiment, WTRU102 can use a sounding reference signal (SRS) that can be precoded using a precoding matrix calculated (e.g., determined) and / or acquired by WTRU102. The precoding / beamforming matrix may consist of (e.g., include) a multiplication of submatrices, including, among other things, a precoding matrix used for digital beamforming and / or a precoding matrix used for analog beamforming.

[0151] WTRU102 can use signals transmitted within the DL to calculate and / or determine a precoding / beamforming matrix for UL transmission. For example, if the precoding / beamforming matrix calculated by WTRU102 is W, the precoded SRS can be given as y=Wt, where t can be the SRS. AP / eNB620 can receive precoded SRS from multiple WTRU102s, including WTRU102s in its own cell and WTRU102s in neighboring cells, and can make scheduling decisions based on the precoded SRS. The matrix used to precode the SRS can be determined by WTRU102 (e.g., completely determined) based on the DL signal (e.g., DL reference signal), and / or can be determined by WTRU102 in part and by AP / eNB620 in part. For example, W=W1W2, or W=W1, and the precoding matrix follows the definition disclosed herein. In one typical embodiment, the WTRU102 can, among other things, (1) determine a first precoding matrix for the SRS by using a DL signal, (2) precode the SRS using the determined matrix, (3) transmit the precoded SRS, and / or (4) receive a second precoding matrix determined by the AP / eNB620. The second precoding matrix can be transmitted within the DL control channel by the AP / eNB620, or by using a pilot precoded with this second precoding matrix. The WTRU102 can form a composite precoding matrix used in data transmission such that the composite matrix is ​​a function of the first and second precoding / beamforming matrices.For example, the first precoding matrix determined by WTRU102 can be based on analog beamforming and can generate a wide beam, while the second precoding matrix determined by WTRU102 can be based on digital beamforming and can cancel out inter-user interference.

[0152] A typical WTRU procedure for UL beamforming operation may consist of or include any of the following: (1) WTRU102 can estimate the UL channel based on DL measurements (e.g.,

[0153]

number

[0154] (2) WTRU102 can estimate the precoding / beamforming matrix / vector W1 based on channel-related measurements. (3) WTRU102 can transmit SRS that can be precoded using the precoding / beamforming matrix / vector W1. (4) WTRU102 can monitor the DL control channel. (5) WTRU102 can decode the relevant payload. (6) WTRU102 can determine the precoding matrix index (PMI) for the precoding / beamforming matrix W2 (for example, (i) the decoded PMI can provide further updates on the channel direction to improve beamforming accuracy, for example, the precoding / beamforming matrix W2 can be used and / or required to cancel multi-user interference, and / or (ii) WTRU102 can explicitly or implicitly identify the precoding matrix / vector W2 (e.g., beamforming matrix) from the decoded PMI). Furthermore / or (7)WTRU102 can beamform the transmitted data vector as y=Wx, where W can be, among other things, a function of the precoding matrices / vectors W1 and W2.

[0155] In one typical embodiment, the precoding / beamforming matrix / vector W2 can be used for data transmission (e.g., y=W2x), and it can be a case where, for example, the precoding / beamforming matrix / vector W1 generates a wide beam, and the precoding / beamforming matrix / vector W2 can be determined from the precoding / beamforming matrix / vector W1 to generate a narrow beam.

[0156] Typical Procedures for UL Beamformed Reciprocity Channel reciprocity can be used to determine a beamforming matrix for UL data transmission based on a beamforming matrix used for DL ​​data reception. For example, (1) data transmitted in the UL direction can be precoded using or with a beamforming matrix that can be used in the receiver to receive DL transmissions. (2) Data transmitted in the UL direction can be precoded using a beamforming matrix that can generate a beam in the same direction as the beamforming matrix used in the receiver to receive DL transmissions. (3) UL SRS can be precoded using the same beamforming matrix used in the receiver to receive DL transmissions. (4) Methods and / or operations disclosed herein can be used to determine a precoding beamforming matrix used for UL data transmissions. And / or (5) the beam widths generated in the WTRU for receiving (e.g., using receive beamforming) and / or for transmitting (e.g., using transmit beamforming) may differ due to differences between the transmitting and receiving hardware. For example, the transmitting beam may be wider than the receiving beam. In this case, the beam used for UL data and / or SRS transmission can be derived based on the DL beam used for data reception. For example, a UL beam can be a beam that is in the same direction as a DL beam and has a wider beam width than a DL beam.

[0157] Those skilled in the art will understand that channel reciprocity exists for both uplink and downlink so that typical procedures / functions / methods / operations can be performed for uplink or downlink communication by reversing the roles / behavior / operations of the uplink entity (e.g., AP / eNB620) and the downlink entity (e.g., WTRU102).

[0158] The representative procedures / functions / methods / operations described herein are intended to be usable within an ad-hoc network and / or a direct peer-to-peer network, so that the representative procedures / functions / methods / operations function between different WTRU102s or between different AP / eNB620s.

[0159] Typical Procedures for Beamformed Transmit Diversity Figure 10A shows the beamformed transmit diversity procedure and operation for a single beam. Figure 10B shows the beamformed transmit diversity procedure and operation for multiple beams of the WTRU and / or AP / eNB. Referring to Figure 10A, WTRU102-1 and / or AP / eNB620-1 can communicate wirelessly using UL and / or DL ​​beams. Referring to Figure 10B, one or more WTRU102-1 (and / or WTRU102-2 not shown), and / or one or more AP / eNB620-1, 620-2 can communicate wirelessly using beams (e.g., UL and / or DL ​​beams). In conjunction with UL beamforming, the antennas (e.g., multiple antennas) of WTRU102-1 (e.g., WTRU transmitters) can be used (e.g., utilized, included, and / or configured, etc.) for rank 1 transmit diversity transmission. In one typical embodiment, the performance of UL transmit diversity can be improved by generating a beammanifold for transmit diversity transmission (e.g., a properly directed beammanifold). For example, a beammanifold can be used to generate any number of beams associated with another beam (e.g., the input beam, the first beam, and / or the original beam) by copying (e.g., duplicating and / or multiplying) that other beam. It is intended that any number of transmit diversity modes may be possible. Transmit diversity modes may include the absence of any channel dimension and / or direction information (e.g., WTRU102-1 may have no channel dimension and / or direction information for performing the transmit diversity procedure). In such cases, the base beammanifold can be derived based on channel reciprocity. A beamformed signal transmitted from one WTRU102-1 to an AP / eNB620-1 (e.g., a transmit / receive point (TRP), eNB, gNB, or AP) can be represented by the following equation 9: y = HW1W2x (9) The precoding / beamforming matrices / vectors W1 and W2 can be based on (for example, respectively) a directed beam manifold and a transmit diversity precoder.

[0160] In a typical embodiment, the precoding / beamforming matrix / vector (e.g., precoder) W1 can be based on channel reciprocity (e.g., derived therefrom). For example, in a TDD system, the precoder can be based on channel estimation (e.g., direct channel estimation and / or statistical channel estimation, among other things) (e.g., using or based on a correlation matrix). In an FDD system, the precoder can be based on statistical channel estimation (e.g., statistical channel estimation only). In a typical embodiment, a typical solution for the precoder W1 can be based on any number of eigendirections of the estimated UL channels. In a typical embodiment, the precoder can be based on DL channel estimation of one or more transmit and receive points (TRPs). In this specification, AP / eNB can be used interchangeably with TRPs and / or APs. For example, WTRU102-1 can generate a single UL beam or multiple UL beams pointing to and / or directed to a single TRP620-1 and / or multiple TRPs620-1, 620-2. In such cases, the WTRU102-1 can generate any number of UL beams simultaneously, opportunistically, and / or based on one or more prior adjustments.

[0161] In one typical embodiment, WTRU102-1 can generate a single or multiple UL beam pointing to and / or directed to another WTRU102-2 and / or multiple WTRU102-2, 102-3. In such a case, WTRU102-1 can generate any number of UL beams simultaneously, opportunistically, and / or based on one or more prior adjustments.

[0162] In one typical embodiment, the TRP620-1 can generate a single or multiple UL beam pointing to and / or directed to WTRU102-1 and / or multiple WTRU102-2, 102-3. In such a case, the TRP620-1 can generate any number of UL beams simultaneously, opportunistically, and / or based on one or more prior adjustments.

[0163] In one typical embodiment, TRP620-1 can generate a single or multiple UL beam pointing to and / or directed to another TRP620 and / or multiple TRP620s. In such cases, TRP620-1 can generate any number of UL beams simultaneously, opportunistically, and / or based on one or more prior adjustments.

[0164] Those skilled in the art will understand that transmit diversity can be provided by a mixture of TRP620 and WTRU102 sharing beams (for example, in an ad hoc network).

[0165] In one typical embodiment, WTRU102 is a precoder W p (For example, an additional precoder W p ) can be used. Precoder W pIt can be used to mitigate faults (e.g., channel estimation errors and / or interference). For example, WTRU102 can be used as a controlled beam perturbation mechanism to reduce the impact of damaged channels (e.g., damaged channel tracking) by adding an additional precoder W p This can be used. The beamformed signal transmitted from one WTRU102 to a network AP / eNB / TRP620 can be represented by the following equation 10. y=HW p W1W2x (10)

[0166] In one typical embodiment, the precoder W p The solution to this can be expressed by the following equation 11, W p =UεV * (11) Here, U and V are,

[0167]

number

[0168] A unitary matrix obtained from the SVD decomposition of the statistical and / or direct estimation of ε, where ε is a diagonal matrix that contains and / or includes the perturbation elements. The perturbation elements are ε i < <d i It can be selected as such, and here, d i For example,

[0169]

number

[0170] These can be eigenvalues ​​associated with (e.g., derived from) the SVD decomposition of the statistical and / or direct estimations of the eigenvalue.

[0171] In one typical embodiment, the precoder W2 can be selected based on the transmit diversity scheme (e.g., a selection of precoder W2 can be provided). For example, the precoder W2 can be selected based on the transmit diversity scheme (e.g., one or more rank 1 transmit diversity schemes), such as space-frequency block coding (SFBC) and / or cyclic delay diversity (CDD). In one typical embodiment, the transmit diversity transmit dimensions (e.g., actual dimensions, e.g., time, frequency, and / or space) may be smaller than the number of transmitter antennas (e.g., total number).

[0172] Typical procedure for DL ​​channel measurement using asymmetric interferometry in WTRU Figure 11 shows an interference source. Referring to Figure 11, the network 600 may include a first cell 610-1 having coverage area 615-1 and a second cell 610-2 having coverage area 615-2. AP / eNB620-1 (for example, An eNB, gNB, and / or other RAN entity may service the first cell 610-1, and AP / eNB620-2 may service the second cell 610-2. The first WTRU102-1 may be within the coverage area 615-1 of the first cell 610-1. The second WTRU102-2 may be within the coverage area 615-2 of the second cell 610-2. WTRU102-2 may transmit and / or send an interference signal (e.g., interference channel v). The effectiveness of channel reciprocity may depend on channel time / frequency coherence, as well as interference in the transmitter and / or receiver. In the case of an asynchronous system (e.g., a TDD system), the sources of interference in the receiver (e.g., WTRU102-1) may be from neighboring base stations (e.g., AP / eNB620-2) and / or inter-cell WTRUs (e.g., 102-2). This can yield DL such that Equation 12 is as follows:

[0173]

number

[0174] Here,

[0175]

number

[0176] This is the measured channel,

[0177]

number

[0178] This is an interference-free DL channel,

[0179]

number

[0180] This is inter-cell interference. Transforming the measured DL channel (e.g., a simple transformation) may result in poor (e.g., very poor) UL performance. Actions, procedures, and / or methods to mitigate the effects of inter-cell interference may include (1) adjustments to orthogonalize the measurement area (e.g., limit the effects of interference). For example, an adjacent base station (e.g., AP / eNB620-2) identified as having an effect on a particular base station (e.g., AP / eNB620-1) may be silenced in an adjusted manner to enable the generation of interference measurement resources to allow for DL ​​channel measurements for a large number of WTRU102-1 within a particular cell 610-1, and / or (2) interference measurements. For example,

[0181]

number

[0182] The immediate or secondary statistics of can be measured.

[0183] Interferometry can be used in one of the following ways: (1) In the case of matrix interferometry (MIM), the effective DL channel used to estimate the UL channel is the intercellular interference

[0184]

number

[0185] A subspace orthogonal to it, or

[0186]

number

[0187] In the subspace spanned by the eigenvectors of,

[0188]

number

[0189] It can be derived from and / or (2) in the case of scalar interferometry (SIM), the interference energy can be obtained as a scalar. For example,

[0190]

number

[0191] It can include...

[0192] For example, if the measured interference falls below a certain threshold (e.g., only in that case), a valid DL channel can be used. The UL channel used is intended to be derivable from a number of DL measurements.

[0193] Typical procedure for UL partial channel reciprocity using a codebook (e.g., using a codebook) A set of precoding vectors for the transmission layer (e.g., each transmission layer and / or each transmission stream) can be used, configured, pre - defined, and / or pre - determined as a codebook. The precoding vectors (e.g., each precoding vector) within the codebook can be associated with an index. Precoding vectors, precoding matrices, precoding weights, precoders, codewords, beamforming vectors, and beam indices can be used interchangeably while still being consistent with the present disclosure. For example, the transmitted signal y at a WTRU transmitter can be y = W c can be represented as y = W c x, where W

[0194]

Number

[0195] can be defined as, where N can be the number of precoding vectors in the codebook.

[0196] In one representative embodiment, the precoding vector W cThe WTRU102 can determine and / or select from, within, the codebook. For example, the WTRU102 can determine a precoding vector associated with an index in the codebook (e.g., within the codebook) based on DL channels that can be estimated, observed, derived, and / or measured from one or more DL signals. The DL signals may include, among other things, (1) a measurement reference signal (RS), (2) demodulated RS (DRS), and / or (3) channel status information (CSI) transmitted from the AP / eNB620. In this specification, the AP / eNB can be used interchangeably with an eNB, gNB, TRP, and / or AP.

[0197] WTRU102 associates and / or includes a pre-coding vector W in the codebook with the codebook based on one or more performance metrics, which may include, in particular, (1) throughput performance, (2) SNR, and / or (3) signal strength. c You can decide and / or choose.

[0198] WTRU102 is a pre-coding vector W associated with the codebook and / or within the codebook, based on the decision for DL ​​signal reception and / or the receiver beam used. c It is possible to determine and / or select the precoding vector W. For example, WTRU102 can receive a DL signal using a determined receiver beam (and / or receiver beam index) within a set of receiver beams, and the precoding vector W c This can be determined based on the receiver beam used and / or the decision.

[0199] WTRU102 is a precoding vector W associated with the codebook and / or within the codebook, based on the CSI provided by the AP / eNB620 and / or DL ​​channel. cIt is possible to determine and / or select the CSI. For example, the CSI can be provided by AP / eNB620 and can be used to determine a subset of associated precoding vectors in the codebook. The WTRU102 determines the precoding vector W within the determined subset of precoding vectors based on the DL channel estimated from the DL signal. c It is possible to select. In one typical embodiment, WTRU102 can determine a subset of precoding vectors associated with and / or within the codebook based on the DL channel estimated from the DL signal. Based on the CSI provided by AP / eNB620, WTRU102 selects the precoding vector W within the subset of precoding vectors. c The CSI can determine the following: The CSI may include, among other things, (1) interference-related information including one or more precoding vectors (e.g., WTRU102 may not use, select, and / or determine precoding vectors that may be shown in the interference-related information), (2) beam-related information including one or more beam directions (e.g., WTRU102 may not use, select, and / or determine beam indices (and / or beam directions) that may be shown in the beam-related information), and / or (3) UL channels measured from the UL signal.

[0200] Pre-coded vector W c This can be determined, used, and / or constructed by one or more component precoding vectors. For example, W cIf =W1W2, then precoders W1 and W2 can be component precoders. In particular, one or more of the following can be applied: (1) Component precoders (e.g., each component precoder) can be selected and / or determined from an associated codebook. (2) The first component precoder (e.g., W1) can be determined by a network entity (e.g., AP / eNB620, core network entity, or another network entity), and / or the second component precoder (e.g., W2) can be determined by WTRU102. (3) The first component precoder W1 can be determined based on a first type of information (e.g., CSI, and / or information associated with channel status), and / or the second component precoder W2 can be determined based on a second type of information (e.g., information associated with DL channel). (4) The first component precoder W1 may be used, indicated, and / or determined in a long-term manner, and the second component precoder W2 may be used, indicated, and / or determined in a short-term manner (for example, the first component precoder W1 may be based on a longer-term criterion than the second component precoder W2). (5) The first component precoder W1 may be used, indicated, and / or determined in a broadband manner, and the second component precoder W2 may be used, indicated, or determined in a subband manner (for example, the first component precoder W1 may be based on a wider bandwidth criterion than the second component precoder W2). And / or (6) The first component precoder may be W1, and the second component precoder may be W2, or vice versa.

[0201] The precoding vector W associated with and / or determined within the codebook. cThis can be implicitly or explicitly indicated to the network 600 and / or AP / eNB620. The determined precoding vector index can be explicitly communicated in the associated UL control signal. For example, the associated UL control signal may be a physical UL control channel (e.g., PUCCH).

[0202] The determined precoding vector index can be implicitly represented based on one or more parameters of the UL DM-RS. For example, one or more orthogonal DM-RSs (e.g., cyclic shifts) can be used, and one of these orthogonal DM-RSs (e.g., cyclic shifts) can be determined based on the determined precoding vector.

[0203] For example, pre-coding vector W c This can be determined by the network entity (e.g., AP / eNB620) and can be shown in WTRU102. WTRU102 is the precoding vector W c Supporting information for decision-making can be reported, shown, and / or provided. For example, pre-coding structure W c =W1W2 can be used as the precoded vector W c Partial information (e.g., precoder W1 and / or precoder W2) may be reported, shown, or provided by WTRU102. One or more of the following may apply: (1) Precoder vector W cTo determine the first and second component precoders can be used. (2) The first component precoder can be determined based on the report of WTRU102 (for example, the index of the precoding vector for the first component precoder can be transmitted or reported from WTRU102). And / or (3) The second component precoder can be determined based on the UL channel estimated, measured, and / or derived from the UL reference signal (e.g., the sounding reference signal (SRS)).

[0204] Pre-coded vector W c Although it is shown as a function of two component precoders (e.g., the first and second component precoders), the precoding vector W c It is intended that this can be a function of any number of component precoders. For example, the precoding vector can be based on three component vectors that can be determined by three or more networks and / or end-user devices.

[0205] Typical AP and / or eNB procedures for disabling WTRU autonomous UL precoding decisions The WTRU102 can determine one or more UL precoding vectors for UL signal transmission. For example, in a WTRU transmitter, one or more transmitting antennas (and / or antenna ports) can be used for UL transmission. One or more precoding vectors for UL transmission can be determined by the WTRU102 based on channels estimated, measured, and / or derived from the DL signal. The WTRU autonomous determination of one or more precoding vectors for UL transmission may result in same-channel interference that is not controlled by the AP / eNB620. The AP / eNB scheduler may, and / or may disable the WTRU determination of one or more precoders if necessary and / or appropriate.

[0206] In one example, an indication may be used to show whether and / or whether WTRU102 may need to use a precoding vector indicated and / or commanded by AP / eNB620 or another network entity. WTRU102 can then determine a precoding vector for UL signal transmission. For example, in a first operating mode, WTRU102 may use a precoding vector indicated by AP / eNB620 for UL signal transmission, and in a second operating mode, WTRU102 may determine a precoding vector for UL signal transmission.

[0207] The first operating mode is sometimes referred to as the fallback UL transmission mode. For example, in the first operating mode, (1) the precoding vector for UL signal transmission can be dynamically indicated in the associated DCI, and in one typical embodiment, the precoding vector can be pre-configured via higher-level layer signaling and can be indicated and / or instructed by AP / eNB620 to use the pre-configured precoding vector (e.g., as used by WTRU102), and / or (2) the precoding vector for UL signal transmission can be randomly determined based on a time / frequency resource index (e.g., precoder cycling can be used in this operating mode).

[0208] The second operating mode is sometimes called the standard UL transmission mode or normal UL transmission mode. For example, in the second operating mode, the precoding vector for UL signal transmission can be determined by the WTRU102 based on the DL channel estimated from the measurement reference signal and / or the CSI provided by the AP / eNB620.

[0209] The operating mode can be indicated, determined, and / or selected based, in particular, on any of the following: (1) DL control information (DCI) (e.g., one or more DCI entries) can be used to indicate the operating mode (e.g., a first DCI format can be used for a first operating mode, and a second DCI format can be used for a second operating mode); (2) A single DCI format with different RNTIs can be used to indicate the operating mode (e.g., a first RNTI for a DCI format can be used for a first operating mode (e.g., to indicate it), and a second RNTI for a DCI format can be used for a second operating mode (e.g., to indicate it) (e.g., (i) the DCI contents for the first RNTI and the second RNTI can be different)). As another example, a precoding matrix representation (PMI) field may exist for a first RNTI, a PMI field may not exist for a second RNTI, and / or (ii) certain fields may be interpreted differently as functions of the RNTI (for example, when, or under the condition that, a first RNTI is used for the DCI format, the PMI field may be used to indicate the precoding vector for UL signal transmission, and / or when, or under the condition that, a second RNTI is used for the DCI format, the PMI field may be used to indicate supporting information for precoding vector determination). And / or (3) bit fields in the associated DCI for UL signal transmission may be used to indicate the operating mode.

[0210] DL control channel search space partitioning can be used to indicate operating modes. For example, the DL control channel search space can be divided into two or more partitions. The first partition of the search space can be used to indicate a first operating mode, and / or the second partition of the search space can be used to indicate a second operating mode.

[0211] In another typical embodiment, the precoding vector can be indicated by AP / eNB620 for frequency-nonselective precoding, and one or more precoding vectors can be determined by WTRU102 for frequency-selective precoding. Frequency-nonselective precoding can use a single precoding vector for UL signal transmission within a given time and frequency window (e.g., one or more TTIs). Frequency-selective precoding can use one or more precoding vectors for UL signal transmission. The precoding vectors for a first time / frequency resource and a second time / frequency resource scheduled for WTRU102 can be different. For example, the first subband and the second subband for UL data transmission within a TTI can have different precoding vectors. Frequency-nonselective precoding can be used interchangeably with the fallback UL transmission mode, and frequency-selective precoding can be used interchangeably with the standard or normal UL transmission mode, or vice versa.

[0212] Typical Hybrid WTRU MIMO Procedure In a hybrid WTRU MIMO procedure, multiple antenna schemes / operations / procedures and corresponding antenna weights can be jointly determined and / or determined by the AP / eNB620 (e.g., gNB) and WTRU102 (e.g., both gNB620 and WTRU).

[0213] In one example, gNB620 can determine and / or decide on a particular set of antenna schemes / operations, and WTRU102 can determine and / or decide on a particular set of antenna weights to be used based on the determined schemes / operations. For example, gNB620 can provide generalized constraints, among which WTRU102 can select a particular and / or special scheme. WTRU102 can select a particular scheme and indicate the scheme to be used during transmission. As an example, gNB620 can specify / indicate that WTRU102 should, can, or will transmit using an antenna diversity scheme (e.g., CDD or STBC) with a specified number of streams.

[0214] As another example, gNB620 may specify / indicate that WTRU102 should, may, or will use a particular rank to specify what should, may, or will be transmitted, and WTRU102 may select a particular scheme within that constraint (e.g., associated with the specified and / or indicated particular rank). For example, gNB620 may set up a UL multi-user MIMO transmission and require WTRU102 to keep its transmission within a predefined subspace and / or restrict WTRU102 to keep it within that subspace.

[0215] In one example, the gNB 620 may determine and / or decide on a wideband or sub-band based weight that can be used by the WTRU 102, and the WTRU 102 may select the particular weight to use. As an example, the gNB 620 may indicate and / or communicate a sub-codebook, or a particular set of codebooks, that can be used by the WTRU 102 for transmission (e.g., UL transmission). The WTRU 102 may select one of the codewords within the codebook for transmission. The WTRU 102 may select (e.g., optimally select) the codeword based on a particular criterion, repeat the codeword in a predetermined manner, and / or randomly select one of the codewords from the codebook.

[0216] For example, the gNB 620 may determine and / or decide on a wideband antenna weight (and / or set of antenna weights) that can be used by the WTRU 102. The WTRU 102 may determine and / or decide on one or more sub-bands (e.g., additional sub-bands) and / or resource element weights that can optimize the performance of the WTRU 102 when given one or more of the gNB 620 commands of antenna weights.

[0217] In some cases, it is intended that one or more broadband (e.g., common) precoders and / or one or more subband / RE-specific precoders may be implemented. RS can be precoded using a broadband (e.g., common) precoder, for example, enabling smoothed channel estimation in or by gNB620. One or more broadband (e.g., common) precoders can be selected, repeated, or randomly selected by gNB620, while one or more subband / RE-based precoders can be selected by WTRU102. WTRU102 can use unprecoded RS, or, in addition to precoders on the data resource, a common RS precoder across one or more frequency bands may be used.

[0218] In a typical autonomous WTRU-MIMO procedure, WTRU102 can estimate the channel based on the DL reference signal transmission from gNB620, for example, by assuming and / or based on channel reciprocity. The DL reference signal should not be precoded, or may need not be precoded (or is precoded using the same beam that gNB620 uses for reception).

[0219] In typical hybrid WTRU MIMO procedures, WTRU102 should and / or may need to have a certain level (e.g., some level) of channel knowledge, and similarly, channel reciprocity can be used.

[0220] Typical Procedures for Displaying WTRU Calibration Capability The WTRU102 can use reciprocity-based measurements based on its calibration status. If the WTRU102 is not properly calibrated, it can fall back to CSI-based operation, and / or may need to fall back to CSI-based operation, or may want to fall back. The calibration status of the WTRU102 can be communicated to the AP / eNB620 in a number of different procedures, operations, and / or methods.

[0221] In one example, the WTRU102 can declare its calibration status through RRC signaling. For instance, the information can be carried as a separate field within the RRC ueCapabilityInformation message. This can take the form of a single-bit flag indicating the calibration status.

[0222] In another example, the WTRU calibration status can be implied by a field, for example, a WTRU category field or ue category field transmitted through or via the RRC ueCapabilityInformation message. A certain WTRU class can be considered calibrated (for example, always considered calibrated).

[0223] In further examples, the WTRU102 can dynamically indicate its calibration status by transmitting a specific signal. Calibration status information can be carried by specific parameters, attributes, and / or resources of the UL signal (e.g., using specific parameters, attributes, and / or resources of the UL signal, such as phase, seed, and / or root sequence, among others). For example, when using the ZC sequence for UL DMRS signaling, SRS signaling, and / or PRACH signaling, information can be indicated by the selection of an appropriate cyclic shift. In another example, information can be derived from the subcarrier location of the UL signal, such as odd / even. In one typical embodiment, calibration status information can be carried directly by a field in the UCI message.

[0224] Figure 12 shows a typical method implemented by WTRU.

[0225] Referring to Figure 12, a typical method 1200 may include, in block 1210, the WTRU 102 determining a first beamforming matrix. In block 1220, the WTRU 102 may transmit a representation of the first beamforming matrix to the network entity 620. In block 1230, the WTRU 102 may receive from the network entity 620 a representation of a second beamforming matrix determined by the network entity 620 from at least the first beamforming matrix, in order to beamform the data to be transmitted. For example, the WTRU may beamform the data to be transmitted using the first and second beamforming matrices.

[0226] Figure 13 shows another typical method implemented by WTRU.

[0227] Referring to Figure 13, a typical method 1300 may include, in block 1310, WTRU 102 determining the UL channel estimation based on DL measurements of the DL channel corresponding to the UL channel. In block 1320, WTRU 102 may determine first beamforming information based on the determined UL channel. In block 1330, WTRU 102 may receive second beamforming information from network entity 620 to beamform data for transmission, the second beamforming information being estimated by the network entity either (1) based on the first beamforming information transmitted to network entity 620 by WTRU 102, or (2) using UL channel-related information.

[0228] In one typical embodiment, the WTRU 102 can transmit the determined first beamforming information to the network entity 620.

[0229] In one typical embodiment, the WTRU102 can beamform the data to be transmitted using first and second beamforming matrices.

[0230] In one typical embodiment, the first beamforming information can be inferred by the network entity 620, which eliminates the need to transmit the first beamforming information to the network entity 620.

[0231] In one typical embodiment, the first beamforming information can be inferred in the network entity 620 based on UL channel statistics.

[0232] In one typical embodiment, the WTRU102 can (1) derive DL channel estimation from DL reference signals or demodulated reference signals embedded in DL data and / or control information, (2) determine linear or nonlinear transformations used to determine UL channel estimation from DL channel estimation, and / or (3) generate UL channel estimation from DL channel estimation and the determined transformations.

[0233] In one representative embodiment, the WTRU102 can derive the first beamforming information from the UL channel estimation, or based on all or a subset of the eigenvectors of the covariance matrix of the UL channel estimation.

[0234] In one typical embodiment, the WTRU102 can transmit one or more precoded reference signals or a representation of a beamforming matrix and / or beamforming vector.

[0235] In one typical embodiment, the representation of the beamforming matrix or beamforming vector may include (1) matrix indices (MIs), (2) a compressed set of values ​​for the beamforming matrix or beamforming vector, and / or (3) a differential MI or vector indicating the difference between vectors previously transmitted to network entity 620 by WTRU102 over frequency and / or time.

[0236] In one typical embodiment, the WTRU102 can receive the second beamforming information periodically or irregularly so that it can update the second beamforming information.

[0237] In one typical embodiment, the first beamforming information can track either (1) channel fluctuations at times and / or frequencies below a threshold, or (2) channel fluctuations at times and / or frequencies above a threshold, and the second beamforming information can track either (1) channel fluctuations at times and / or frequencies below a threshold, or (2) channel fluctuations at times and / or frequencies above a threshold.

[0238] In one typical embodiment, the WTRU102 can measure the angle of arrival (AOA) of the signal at the DL, and first beamforming information can be determined using the measured AOA.

[0239] In one typical embodiment, the WTRU102 can determine the precoding vector based on either (1) a receiver beam or receiver beam index for receiving DL signals, and / or (2) channel state information (CSI) provided, for example, by a network entity 620 and / or via the DL channel.

[0240] In one typical embodiment, the CSI may include any of the following: (1) interference-related information, (2) beam-related information, and / or (3) UL channel-related information measured from the UL signal.

[0241] In one typical embodiment, WTRU102 can combine a first component precoder associated with information obtained from network entity 620 with a second component precoder determined by WTRU102.

[0242] In one representative embodiment, the first component precoder can be selected based on either (1) a criterion associated with a time frame longer than the criterion of the second component precoder, and / or (2) a corresponding bandwidth wider than the corresponding bandwidth of the second component precoder.

[0243] Figure 14 shows further representative methods implemented by WTRU.

[0244] Referring to Figure 14, a typical method 1400 may include, in block 1410, WTRU 102 determining the UL channel estimation based on DL measurements of the DL channel corresponding to the UL channel. In block 1420, WTRU 102 can receive and decode a payload relating to the interference channel associated with the interference direction. In block 1430, WTRU 102 can determine the beamforming matrix index from the decoded payload. In block 1440, WTRU 102 can determine the beamforming matrix and / or beamforming vectors based on the estimated UL channel and interference channel, such that the interference channel lies in the null space of the beamforming matrix or beamforming vector. In block 1450, WTRU 102 can beamform the data for transmission using the determined beamforming matrix and / or beamforming vectors.

[0245] In one typical embodiment, the WTRU 102 can receive a payload containing beamforming information associated with interference channels via the network entity 620. For example, the interference channels can be a single interference channel or a combination of multiple interference channels.

[0246] In one typical embodiment, the WTRU102 can determine the beamforming matrix and / or beamforming vectors such that the column space of the beamforming matrix and / or beamforming vectors is orthogonal to the column space of the matrix or vectors indicated by the included beamforming information.

[0247] In one typical embodiment, the WTRU 102 can receive information indicating the direction of the interference channel via the network entity 620, and can determine a beamforming matrix and / or beamforming vector to avoid or substantially avoid using the indicated direction.

[0248] In one typical embodiment, the WTRU 102 can receive directional information via the network entity 620 and determine a beamforming matrix and / or beamforming vector to use the indicated direction.

[0249] Figure 15 shows a diagram illustrating additional typical methods implemented by WTRU.

[0250] Referring to Figure 15, a typical method 1500 may include, in block 1510, WTRU 102 determining the UL channel estimation based on DL measurements of the DL channel corresponding to the UL channel. In block 1520, WTRU 102 can transmit the SRS precoded using the first beamforming information to the network entity 620. In block 1530, WTRU 102 can receive the payload from the network entity 620. In block 1540, WTRU 102 can determine the matrix index for the second beamforming information from the payload. In block 1550, WTRU 102 can identify the second beamforming information from the determined matrix index. In block 1560, WTRU 102 can beamform the data for transmission using the first and second beamforming information.

[0251] In one typical embodiment, WTRU102 can monitor and decode matrix indices.

[0252] In one typical embodiment, the reception of the second beamforming information may occur periodically or irregularly so that the second beamforming information is updated.

[0253] Figure 16 shows another representative method implemented by WTRU.

[0254] Referring to Figure 16, a typical method 1600 may include, in block 1610, WTRU 102 determining the UL channel estimation based on DL measurements of the DL channel corresponding to the UL channel. In block 1620, WTRU 102 may transmit to access point (AP) 620 a set of recommended precoders, or one or more codebook values ​​representing a set of recommended precoders. In block 1630, WTRU 102 may receive from the AP any of the following: (1) an indication that the recommended precoders determined by the WTRU should be used for UL communication with the AP; (2) one or more codebook values ​​indicating one or more selected precoders for UL communication with the AP; and / or (3) a set of selected precoders for UL communication with the AP.

[0255] Figure 17 shows additional typical methods implemented by WTRU.

[0256] Referring to Figure 17, a typical method 1700 may include, in block 1710, WTRU 102 determining the UL channel estimation based on DL measurements of the DL channel corresponding to the UL channel. In block 1720, WTRU 102 may select one or more precoders based on the determined estimation of the UL channel. In block 1730, WTRU 102 may receive a disabling indicator from AP to disable one or more selected precoders. For example, the disabling indicator may indicate whether WTRU 102 can or should use a precoding vector indicated by AP, associated with a first operating mode, for UL signal transmission, or whether WTRU 102 can or should use a precoding vector set by WTRU, associated with a second operating mode, for UL signal transmission. In the first operating mode, the precoding vector for UL signal transmission can be any of the following: (1) dynamically indicated within downlink control information, (2) pre-configured via higher-layer signaling, or (3) randomly determined based on a time / frequency resource index. In the second operating mode, the precoding vector for UL signal transmission can be determined by WTRU102 based on the DL channel estimated from the measurement reference signal and / or channel state information provided by AP620.

[0257] In one representative embodiment, the operating mode can be indicated by any of the following: (1) a DCI such that a first downlink control channel (DCI) format can indicate a first operating mode and a second DCI format can indicate a second operating mode; (2) different RNTIs such that a first RNTI for a single DCI format can indicate a first operating mode and a second RNTI for a single DCI format can indicate a second operating mode; and / or (3) a bit field in a DCI for UL signal transmission that can indicate an operating mode.

[0258] In one typical embodiment, a precoding vector for frequency-nonselective precoding can be represented by AP620, and one or more precoding vectors for frequency-selective precoding can be determined by WTRU102.

[0259] Figure 18 shows another typical method implemented by WTRU.

[0260] Referring to Figure 18, a typical method 1800 may include, in block 1810, the WTRU 102 determining, based on the calibration state of the WTRU, whether to estimate the UL channel using channel reciprocity. In block 1820, given that the calibration state is sufficient to use channel reciprocity, the WTRU 102 may determine the UL channel estimation based on DL measurements of the DL channel corresponding to the UL channel. In block 1830, given that the calibration state is insufficient to use channel reciprocity, the WTRU 102 may determine the UL channel estimation using channel state information. In block 1840, the WTRU 102 may determine one or more precoding vectors for UL communication with AP620 based on the determined UL channel estimation. For example, the calibration state may be a single-bit flag carried in the RRC message.

[0261] Figure 19 shows a typical method implemented by the NE. Referring to Figure 19, the typical method 1900 may include, in block 1910, for each of the multiple WTRU102s, the NE620 receiving or inferring first beamforming information from each WTRU102, determining second beamforming information associated with each WTRU102 based on the received or inferred first beamforming information, and transmitting the second beamforming information to each WTRU102.

[0262] Figure 20 shows another typical method implemented by the NE. Referring to Figure 20, typical method 2000 may include, in block 2010, for each WTRU102-1 of a plurality of WTRU102-1, 102-2...102-K, the NE620 receiving beamforming information, determining combined interference channel information associated with WTRU102-2...102-K other than the respective WTRU102-1 based on the received beamforming information, and transmitting the combined interference channel information to each WTRU102-1. For example, the combined interference channel information may indicate or include (1) a first direction included for beamforming of each WTRU102-1, (2) a second direction to be avoided for beamforming of each WTRU102-1, and / or (3) any of the matrices or vectors for orthogonalizing the column space of a second beamforming matrix or second beamforming vector to the column space of matrices or vectors shown or included.

[0263] Figure 21 shows further representative methods implemented by NE.

[0264] Referring to Figure 21, a typical method 2100 may include, in block 2110, for each WTRU102-1 of a plurality of WTRU102-1, 102-2...102-K, the NE620 receiving a precoded SRS from each WTRU102-1 using first beamforming information, determining second beamforming information using at least the received precoded SRS, and transmitting a payload to each WTRU102 containing a matrix index relating to the second beamforming information.

[0265] Figure 22 shows an additional typical method implemented by the NE. Referring to Figure 22, a typical method 2200 may include, in block 2210, the NE620 determining the UL channel estimation based on UL measurements for a plurality of WTRU102s. In block 2220, the NE620 may receive a set of recommended precoders, or one or more codebook values ​​representing a set of recommended precoders, from each of the plurality of WTRU102s, WTRU102-1, 102-2...102-K. In block 2230, the NE620 may select, for example, at least one precoder for each of the plurality of WTRU102s, WTRU102-1, based on the received set of recommended precoders, in order to reduce or minimize mutual interference for UL communications from the plurality of WTRU102s. In block 2240, NE620 may transmit any of the following: (1) an indication that a recommended precoder determined by WTRU102 can or should be used for UL communication with NE620; (2) one or more codebook values ​​indicating one or more selected precoders for UL communication with NE620; and / or (3) a set of selected precoders for UL communication with NE620.

[0266] In one typical embodiment, the NE620 can analyze any of the interference and / or scheduling requirements of multiple WTRU102s.

[0267] Figure 23 shows further typical methods implemented by WTRU for transmit diversity mode.

[0268] Referring to Figure 23, a typical method 2300 may include, in block 2310, WTRU 102 pre-configuring first pre-coding information for data communication with NE 620 in transmit diversity mode. In block 2320, WTRU 102 may determine the UL channel estimation based on DL measurements of the DL channel corresponding to the UL channel. In block 2330, WTRU 102 may determine second pre-coding information based on the UL channel estimation. In block 2340, WTRU 102 may communicate data with NE 620 using the pre-configured first and second pre-coding information. For example, the first pre-coding information may be either static or semi-static information (1) pre-configured in WTRU 102 and / or (2) transmitted by NE 620 as information for open-loop pre-coding of data for communication by WTRU 102.

[0269] In one typical embodiment, the first precoding information can be associated with one or more transmit diversity modes of the WTRU102.

[0270] In one typical embodiment, the WTRU102 can transmit UL transmissions over multiple antennas 122. For example, the number of antennas 122 can be greater than the dimension associated with the UL transmission.

[0271] In one representative embodiment, the second precoding information may include information associated with beamforming, and (1) for TDD systems, it may be based on either direct channel estimation and / or statistical channel estimation, and / or (2) for FDD systems, it may be based on statistical channel estimation.

[0272] In one representative embodiment, the second precoding information can be based on the eigendirection of the UL channel estimation.

[0273] In one typical embodiment, the first precoding information can be used by WTRU102 for one or more durations while WTRU102 is operating in transmit diversity mode.

[0274] In one typical embodiment, the WTRU102 can generate UL transmissions using a beam manifold so that the beam manifold can be used to transmit UL transmissions in two or more directions.

[0275] In one representative embodiment, the WTRU102 can determine the third precoding information based on perturbation elements. For example, the third beamforming information can be based on a diagonal matrix ε containing perturbation elements. The perturbation elements contained in the diagonal matrix ε are ε i < <d i It can be selected as such, and here, d i These are eigenvalues ​​obtained from singular value decomposition (SVD) of either statistical channel estimation or / or direct channel estimation.

[0276] In one representative embodiment, WTRU102 can determine two or more estimations associated with two or more UL channels. The determined UL channels can be transmitted simultaneously, opportunistically, and / or based on prior coordination.

[0277] Figure 24 shows typical methods implemented by WTRUs to manage UL MIMO communications.

[0278] Referring to Figure 24, a typical method 2400 may include, in block 2410, WTRU 102 transmitting one or more reference signals (RS) to NE 620. In block 2420, WTRU 102 may receive a message from NE 620 containing or indicating first precoding constraint information. In block 2430, WTRU 102 may determine second precoding constraint information according to the first precoding constraint information received or indicated in the message. In block 2440, WTRU 102 may select a precoder for UL communication using at least the determined second precoding constraint information. In block 2450, WTRU 102 may transmit UL MIMO communication to NE 620 using the selected precoder.

[0279] In one typical embodiment, the message may include, as first precoding constraint information, information indicating any of the following: (1) a set of broadband antenna weights, (2) one or more sets of subband antenna weights, (3) a range of broadband antenna weights, and / or (4) one or more ranges of subband antenna weights.

[0280] In one typical embodiment, WTRU102 can select one or more specific antenna weights from among the antenna weights indicated in the message as second precoding constraint information.

[0281] In one typical embodiment, the message may indicate, or include, as first precoding constraint information, a codeword associated with a codebook, or a specific set of codewords from which WTRU102 should select for UL MIMO communication.

[0282] In one representative embodiment, WTRU102 can determine the second precoding constraint information in accordance with the first precoding constraint information by any of the following: (1) selecting one of the indicated or included codewords based on a specific criterion; (2) selecting one of the indicated or included codewords by repeating the indicated or included codewords in a predetermined manner; and / or (3) randomly selecting one of the indicated or included codewords.

[0283] In one representative embodiment, WTRU102 can determine the second precoding constraint information in accordance with the first precoding constraint information by any of the following: (1) selecting one of the indicated or included codewords based on a specific criterion; (2) selecting one of the indicated or included codewords by repeating the indicated or included codewords in a predetermined manner; and / or (3) randomly selecting one of the indicated or included codewords.

[0284] In one typical embodiment, the message may include information indicating broadband antenna weights, and WTRU102 may determine one or more subband and / or resource element weights according to the indicated broadband antenna weights.

[0285] In one typical embodiment, WTRU102 can select one or more specific antenna weights as second precoding constraint information from among the antenna weights indicated in the message.

[0286] In one typical embodiment, the WTRU102 can determine antenna weights for UL MIMO communication based on first precoding constraint information, and can select a precoder using second precoding constraint information and the determined antenna weights.

[0287] In one typical embodiment, the first precoding constraint information may include information indicating any of the following: (1) a specific multiple antenna scheme, (2) a transmission scheme, (3) a specified number of streams, (4) a subspace constraint indicating a subspace within which transmission from WTRU102 is constrained, and / or (5) a rank. For example, a specific multiple antenna scheme may include any of the following: (1) a time diversity scheme, (2) a spatial diversity scheme, and / or (3) a frequency diversity scheme, (4) a polarization diversity scheme, (5) a multi-user diversity scheme, (6) a cooperative diversity scheme, (7) a space-time block coding (STBC) scheme, and / or (8) a cyclic delay diversity (CDD) scheme.

[0288] In one typical embodiment, the message may be received (1) on a downlink control channel, (2) within an uplink grant, and / or (3) as control signaling.

[0289] In one typical embodiment, the representation may be (1) a codeword and / or (2) a precoding or beamforming matrix index (PMI).

[0290] In one typical embodiment, one or more reference signals (RS) can be multidimensional sounding RS. For example, the multidimensional sounding RS may have dimensions based on any of the following: (1) the number of transmitting antennas of the WTRU, (2) the characteristics of the transmitting antennas of the WTRU102, and / or (3) the number of effective transmitting beams of the WTRU102.

[0291] In one typical embodiment, WTRU102 can receive one or more RSs from NE620 as one or more feedback RSs, and the channel can be estimated using one or more feedback RSs.

[0292] In one typical embodiment, one or more RSs may or may not precode using the same beam that the NE620 uses for reception.

[0293] Figure 25 shows typical methods implemented by NEs to manage UL MIMO communications.

[0294] Referring to Figure 25, a typical method 2500 may include, in block 2510, NE620 receiving one or more reference signals (RS) from WTRU102. In block 2520, NE620 may estimate the channel based on the received one or more RSs. In block 2530, NE620 may determine first precoding constraint information. In block 2540, NE620 may transmit the first precoding constraint information, or a representation of the first precoding constraint information, to WTRU102. In block 2550, NE620 may decode the UL MIMO communication based on the estimated channel.

[0295] In one typical embodiment, the NE620 can transmit the indication in any of the following ways: (1) over the downlink control channel, (2) within the uplink grant, and / or (3) as control signaling.

[0296] In one typical embodiment, the NE620 can transmit the display either (1) within a codeword and / or (2) within a precode or beamforming matrix index (PMI).

[0297] In one typical embodiment, one or more reference signals (RS) can be multidimensional sounding RS. For example, the multidimensional sounding RS may have dimensions based on any of the following: (1) the number of transmitting antennas of WTRU102, (2) the characteristics of the transmitting antennas of WTRU102, and / or (3) the number of effective transmitting beams of WTRU102.

[0298] In one typical embodiment, the first precoding constraint information may include information indicating any of the following: (1) a specific multiple antenna scheme, (2) a transmission scheme and a specified number of streams, (3) a subspace constraint indicating a subspace in which transmission from WTRU102 is constrained, and / or (4) a rank.

[0299] In one typical embodiment, the first precoding constraint information may include a set of broadband or subband-based antenna weights and / or information indicating a range of antenna weights.

[0300] While features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. In addition, the methods described herein can be implemented in computer programs, software, or firmware contained within a computer-readable medium for execution by a computer or processor. Examples of non-temporary computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital multi-purpose disks (DVDs). A processor in conjunction with software can be used to implement a radio frequency transceiver for use in a UE, WTRU, terminal, base station, RNC, or any host computer.

[0301] Furthermore, in the embodiments described above, other devices including processing platforms, computing systems, controllers, and processors have been mentioned. These devices may include at least one central processing unit ("CPU") and memory. In accordance with the conventions of those skilled in the field of computer programming, references to acts and symbolic representations of actions or instructions may be performed by various CPUs and memories. Such acts and actions or instructions may be said to be "executed," "computer-executed," or "CPU-executed."

[0302] Those skilled in the art will understand that actions, and symbolically represented actions or instructions, involve the manipulation of electrical signals by the CPU. An electrical system can cause the resulting transformation or modification of electrical signals and the preservation of data bits in memory locations within a memory system, thereby reconfiguring or otherwise modifying the CPU's actions and other processing of signals. The memory locations where data bits are preserved are physical locations having specific electrical, magnetic, optical, or organic properties corresponding to or representing the data bits. It should be understood that exemplary embodiments are not limited to the platforms or CPUs described above, and other platforms and CPUs may support the methods provided.

[0303] Data bits may also be maintained on computer-readable media, including magnetic disks, optical disks, and any other volatile (e.g., Random Access Memory “RAM”) or non-volatile (e.g., Read-Only Memory “ROM”) large-scale storage systems that are readable by the CPU. Computer-readable media may include cooperative or interconnected computer-readable media that are distributed among a number of interconnected processing systems that may reside exclusively on a processing system or be local or remote to a processing system. Typical embodiments are not limited to the memories described above, and it is understood that other platforms and memories may support the methods described.

[0304] In descriptive embodiments, any of the operations, processes, etc., described herein can be implemented as computer-readable instructions stored on a computer-readable medium. These computer-readable instructions can be executed by a processor in a mobile unit, network element, and / or any other computing device.

[0305] There are only minor differences between hardware and software implementations of a system configuration. The choice between using hardware or software is generally (though not always) a design choice representing a cost-efficiency trade-off, as in some situations the choice between hardware and software can be critical. Various means (e.g., hardware, software, and / or firmware) can be used to achieve the processes and / or systems and / or other technologies described herein, and the preferred means can vary depending on the context in which the processes and / or systems and / or other technologies are deployed. For example, if the implementer determines that speed and accuracy are paramount, they may primarily choose hardware and / or firmware means. If flexibility is paramount, they may primarily choose software implementation. Alternatively, they may choose any combination of hardware, software, and / or firmware.

[0306] The detailed descriptions above illustrate various embodiments of devices and / or processes through the use of block diagrams, flowcharts, and / or examples. To the extent that such block diagrams, flowcharts, and / or examples include one or more functions and / or operations, it will be understood by those skilled in the art that each function and / or operation in such block diagrams, flowcharts, or examples can be implemented individually and / or collectively by a wide range of hardware, software, firmware, or substantially any combination thereof. Suitable processors include, by example, general-purpose processors, dedicated processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors working with a DSP core, controllers, microcontrollers, application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), field-programmable gate array (FPGA) circuits, any other type of integrated circuit (IC), and / or state machines.

[0307] While features and elements are described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. This disclosure should not be limited to the specific embodiments described herein, intended as a description of various aspects. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from its spirit and scope. Elements, actions, or commands used in the description of this application should not be construed as essential or indispensable to the invention unless expressly provided as such. In addition to those enumerated herein, functionally equivalent methods and apparatus within the scope of this disclosure will be apparent to those skilled in the art from the above description. Such modifications and variations are intended to be covered within the appended claims. This disclosure should be limited only by the language of such claims, together with the entire scope of equivalents to which the appended claims are entitled. It should be understood that this disclosure should not be limited to any particular method or system.

[0308] The terms used herein are intended solely to describe specific embodiments and are not intended to be limiting. Where used herein, the term “User Equipment” and its abbreviation “UE” can mean (i) any of the various embodiments of a wireless transmit and / or receive unit (WTRU) as described below, (ii) any of the various embodiments of a WTRU as described below, (iii) a wireless and / or wired (e.g., connectable) device configured using some or all of the structures and functionalities of a WTRU, as described below, (iv) a wireless and / or wired device configured using fewer structures and functionalities than all of a WTRU, as described below, or (v) similar. Details of exemplary WTRUs that can represent any of the WTRUs listed herein are provided below with respect to Figures 1 to 5.

[0309] In some representative embodiments, some parts of the subject matter described herein can be implemented via application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other integrated forms. However, some aspects of the embodiments disclosed herein can be equivalently implemented in an integrated circuit, in whole or in part, as one or more computer programs running on one or more computers (e.g., one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., one or more programs running on one or more microprocessors), as firmware, or substantially any combination thereof. Those skilled in the art will recognize that designing the circuits and / or writing the code for the software and / or firmware is well within the skill of those skilled in the art, given this disclosure. In addition, those skilled in the art will understand that the mechanisms of the subject matter described herein can be distributed in various forms as program products, and that the descriptive embodiments of the subject matter described herein are applicable regardless of the specific type of signal carrier used to actually carry out the distribution. Examples of signal carriers include, but are not limited to, recordable media such as floppy disks, hard disk drives, CDs, DVDs, digital tapes, and computer memory, as well as transmission media such as digital and / or analog communication media (e.g., fiber optic cables, waveguides, wired communication links, wireless communication links, etc.).

[0310] The subject matter described herein sometimes describes different components that are contained within or connected to other different components. It should be understood that such shown architectures are merely examples, and that in practice, many other architectures can be implemented to achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” in such a way that the desired functionality can be achieved. Thus, any two components in this specification that are combined to achieve a particular functionality can be seen as “associated” with each other, regardless of whether they are architectures or intermediary components, in such a way that the desired functionality can be achieved. Similarly, any two components that are thus associated can also be seen as “operably connected” or “operably coupled” with each other in order to achieve the desired functionality, and any two components that can be associated in such a way can also be seen as “operably coupled” with each other in order to achieve the desired functionality. Specific examples of components that can be operationally coupled include, but are not limited to, physically connectable and / or physically interacting components, as well as / or wirelessly interactable and / or wirelessly interacting components, as well as logically interactable and / or logically interacting components.

[0311] In substantially any use of plural and / or singular terms herein, a person skilled in the art can convert from plural to singular and / or singular to plural as appropriate to the context and / or use. Various singular / plural substitutions may be explicitly described herein for clarity.

[0312] In general, it will be understood by those skilled in the art that the terms used herein, and in particular in the appended claims (e.g., the text of the appended claims), are generally intended as “open” terms (for example, the term “including” should be interpreted as “including, without limitation, “having” should be interpreted as “having at least one” and the term “includes” should be interpreted as “including, without limitation, “including”). It will also be understood by those skilled in the art that if a specific number of claimed items is intended, such intention is explicitly stated in the claim, and if such statement is not made, such intention does not exist. For example, if only one item is intended, the term “single” or similar wording may be used. For the sake of understanding, the following appended claims and / or descriptions herein may include the use of the introductory phrases “at least one” and “one or more” to introduce claimed items. However, the use of such phrases should not be interpreted as implying that the introduction of a claimed item with the indefinite article "a" or "an" limits any particular claim containing such introduced claimed item to embodiments containing only one such item, even when the same claim contains the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (for example, "a" and / or "an" should be interpreted as meaning "at least one" or "one or more"). The same is true of the use of the definite article used to introduce a claimed item. In addition, a person skilled in the art will recognize that even when a specific number is explicitly stated with respect to the claimed items being introduced, such statement should be interpreted as meaning at least the stated number (for example, the minimal statement "two items" without other modifying phrases means at least two items, or two or more items).Furthermore, when expressions similar to "at least one of A, B, and C" are used, such constructions are generally intended to be understood by those skilled in the art (for example, "a system having at least one of A, B, and C" includes, without limitation, a system having only A, a system having only B, a system having only C, a system having both A and B, a system having both A and C, a system having both B and C, and / or a system having both A, B and C). It will be further understood by those skilled in the art that substantially any separate word and / or phrase presenting two or more alternative words, whether in the description, claims, or drawings, should be understood as construing the possibility of including one of the words, either of the words, or both of the words. For example, the phrase “A or B” is understood to include the possibilities of “A” or “B” or “A and B.” Furthermore, the word “any of ~” followed by an enumeration of multiple words and / or categories of multiple words, when used herein, is intended to include “any of” words and / or categories of words, “any combination of” words and / or categories of words, “any multiple” words and / or categories of words, and / or “any combination of multiple” words and / or categories of words, individually or in combination with other words and / or categories of other words. Furthermore, when used herein, the words “set” or “group” are intended to include any number of items, including zero.In addition, as used herein, the term “number” is intended to include any number, including zero.

[0313] In addition, if any feature or aspect of the present disclosure is described by a group of Markush members, a person skilled in the art will recognize that the present disclosure is also described by any individual member or subgroup of a member of the group of Markush members.

[0314] For any and all purposes relating to providing a written description, as can be understood by those skilled in the art, all scopes disclosed herein also encompass any and all possible subscopes and combinations of subscopes. Any listed scope can be readily recognized as fully describing and enabling the same scope to be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each scope described herein can be readily divided into a lower third, a middle third, an upper third, etc. Again, as can be understood by those skilled in the art, all words such as “at most,” “at least,” “greater than,” and “less than,” include the stated number and refer to a scope that can later be broken down into subscopes as described above. Finally, as can be understood by those skilled in the art, a scope includes each individual member. Thus, for example, a group having one to three cells refers to a group having one, two, or three cells. Similarly, a group having one to five cells refers to a group having one, two, three, four, or five cells, and so on.

[0315] Furthermore, unless otherwise stated, the claims should not be interpreted as being limited to the order or elements provided. In addition, the use of the phrase “means for” in any claim is intended to invoke § 112, paragraph 6 of the U.S. Patent Act, or the means-plus-function claim format, and no claim that does not use the phrase “means for” is intended to do so.

[0316] A processor in conjunction with software may be used to implement a radio frequency transceiver for use in a Wireless Transceiver Unit (WTRU), User Equipment (UE), Terminal, Base Station, Mobility Management Entity (MME) or Evolutionary Packet Core (EPC), or any host computer. The WTRU may be used in conjunction with other components such as modules implemented in hardware and / or software, including software-defined radio (SDR), as well as cameras, video camera modules, videophones, speakerphones, vibration devices, speakers, microphones, television transceivers, hands-free headsets, keyboards, Bluetooth® modules, frequency modulation (FM) radio units, near-field communication (NFC) modules, liquid crystal display (LCD) units, organic light-emitting diode (OLED) display units, digital music players, media players, video game player modules, internet browsers, and / or any wireless local area network (WLAN) or ultra-wideband (UWB) modules.

[0317] Although the present invention has been described in relation to a communication system, the system is intended to be implemented in software on a microprocessor / general-purpose computer (not shown). In some embodiments, one or more functions of various components can be implemented by software that controls the general-purpose computer.

[0318] In addition, although the present invention has been shown and described herein with reference to specific embodiments, the present invention is not intended to be limited to the details shown. Rather, various modifications can be made to the details within the scope of the claims and their equivalents without departing from the present invention. [Explanation of symbols]

[0319] 102a~102d WTRU 103, 104, 105 RAN 106, 107, 109 Core Network 108 PSTN 110 Internet 112 Other networks 114a, 124b base station 118 processors 120 Transceivers (Transmitters and Receivers) 122 Antenna

Claims

1. In a method of uplink (UL) transmission performed by a wireless transceiver unit (WTRU) using multiple sounding reference signals (multiple SRS), The steps include measuring one or more downlink (DL) reference signals (RS) using the WTRU, The steps include: using the WTRU to precode at least one of the plurality of SRSs using a first set of precoding information based on one or more measured DLRSs; The steps include: transmitting to a network entity, via the WTRU, at least one of the precoded SRS, which includes displaying the set of first precoding information recommended by the WTRU; The steps include receiving a UL grant from the WTRU that includes an indicator showing second precoding information based on at least one of the precoded SRS, The WTRU performs the step of precoding the UL data using the second precoding information shown above, The WTRU transmits the UL data precoded using the second precoding information indicated above. A method for providing this.

2. The method according to claim 1, further comprising the step of using the WTRU to identify a subset of the set of first precoding information as second precoding information based on the indicators included in the UL grant.

3. The method according to claim 2, wherein the second precoding information is used to generate any of the following: (1) a beam in a particular direction; (2) a beam that avoids or substantially avoids an interference direction; (3) a beam that cancels or reduces interference between the WTRU and one or more further WTRUs; or (4) a beam having null space corresponding to an interference direction associated with at least one other WTRU.

4. The method according to claim 1, wherein at least one of the plurality of SRSs and the UL data are precoded differently.

5. The method according to claim 1, wherein the set of first precoding information used to precode at least one of the plurality of SRS is determined by the WTRU based on the measured DLRS.

6. The method according to claim 5, wherein the measured DL RS is one or more channel state information (CSI) RS.

7. The method according to claim 1, wherein the indicator is an index for identifying the second precoding information.

8. In a wireless transceiver unit (WTRU) configured to transmit uplink (UL) data using multiple sounding reference signals (multiple SRS), Measure one or more downlink (DL) reference signals (RS), and, Using the first set of precoding information based on one or more measured DL RSs, precode at least one of the plurality of SRSs. A processor configured as follows, Transmit to the network entity at least one of the precoded SRS, which includes a display of the set of first precoding information recommended by the WTRU, Receives a UL grant including an indicator showing second precoding information based on at least one of the precoded SRS. A transceiver configured as follows Equipped with, The processor is configured to precode UL data using the second precoding information described above. The transceiver is configured to transmit the UL data that has been precoded using the second precoding information indicated above. WTRU.

9. The WTRU according to claim 8, wherein the processor is configured to identify a subset of the set of first precoding information based on the indicators included in the UL grant.

10. The WTRU according to claim 9, which is used to generate any of the following: (1) a beam in a particular direction; (2) a beam that avoids or substantially avoids an interference direction; (3) a beam that cancels or reduces interference between the WTRU and one or more further WTRUs; or (4) a beam having null space corresponding to an interference direction associated with at least one other WTRU.

11. The WTRU according to claim 8, wherein at least one of the plurality of SRSs and the UL data are precoded differently.

12. The WTRU according to claim 8, wherein the indicator is an index for identifying the second precoding information.

13. The WTRU according to claim 8, wherein the processor is configured to determine the set of first precoding information used to precode at least one of the plurality of SRSs based on the measured DLRS.

14. The WTRU according to claim 13, wherein the measured DL RS is one or more channel state information (CSI) RS.

15. A network access point (NAP) configured to provide precoding assistance to a wireless transceiver unit (WTRU) using multiple sounding reference signals (multiple SRS), A transceiver configured to receive from the WTRU at least one of the precoded SRSs, including a display of a first set of precoding information recommended by the WTRU, Determine the set of displayed first precoding information associated with at least one of the precoded SRS, A subset of the set of the first precoding information is selected, and A processor configured to send a UL grant to the WTRU, which includes an indicator showing the selected subset of the set of first precoding information. Equipped with, The transceiver is configured to receive UL data from the WTRU, The processor is configured to decode the UL data using the subset of the set of first precoding information. NAP.

16. The NAP according to claim 15, wherein at least one of the plurality of SRSs and the UL data are precoded differently.

17. The NAP according to claim 15, wherein the indicator is an index for identifying the subset of the set of first precoding information.

18. The NAP according to claim 15, wherein the processor is configured to select the subset of the first precoding information based on the generation of any of the following: (1) a beam in a particular direction; (2) a beam that avoids or substantially avoids the interference direction; (3) a beam that cancels or reduces interference between the WTRU and one or more further WTRUs; or (4) a beam having null space corresponding to the interference direction associated with at least one other WTRU.

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