Single layer mimo coverage enhancement using enhanced precoder codebook

Abstract

Various aspects of the disclosure relate to a user equipment (UE) for wireless communication, comprising at least one memory and at least one processor coupled with the at least one memory and configured to cause the UE to: transmit, to a network entity, an indication indicating a capability of the UE comprising an enhanced codebook for single layer uplink multiple-input multiple-output (MIMO) transmissions; and receive, from the network entity, a transmission precoding matrix indicator (TPMI) indicating a value of an enhanced precoder codebook, wherein the enhanced precoder codebook comprises a precoder for each combination in which a phase rotation of a first antenna port relative to each of one or more remaining antenna ports of the UE relative to the first antenna port is a multiple of 90 degrees and the value is associated with a precoder of the enhanced precoder codebook to be used by the UE for an uplink transmission.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 553,863, filed February 15, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to wireless communications, and more specifically, to enhanced precoder codebooks. Background Technology

[0003] A wireless communication system may include one or more network communication devices (such as base stations), and others that may support wireless communication with one or more user communication devices, which may also be referred to as user equipment (UE) or another suitable term. The wireless communication system can support wireless communication with one or more user communication devices by utilizing the resources of the wireless communication system (e.g., time resources (e.g., symbols, time slots, subframes, frames, etc.) or frequency resources (e.g., subcarriers, carriers, etc.)). Additionally, the wireless communication system may support wireless communication across a variety of radio access technologies, including third-generation (3G) radio access technology, fourth-generation (4G) radio access technology, fifth-generation (5G) radio access technology, and other suitable radio access technologies beyond 5G (e.g., sixth-generation (6G)). Summary of the Invention

[0004] The article “a” preceding an element is unrestricted and is understood to refer to “at least one” or “one or more” of these elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” are interchangeable. As used herein, including in claims, the word “or” in a list of items (e.g., a list of items beginning with phrases such as “at least one of…” or “one or more of…” or “one or both of…”) indicates an inclusive list, such that a list of at least one of, for example, A, B, or C represents A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Furthermore, as used herein, the phrase “based on” should not be construed as a reference to a closed set of conditions. For example, an example step described as “based on condition A” may be based on conditions A and B without departing from the scope of this disclosure. In other words, as used herein, the phrase “based on” should be interpreted in the same manner as the phrase “at least partially based on.” Further, as used herein, including in claims, “set” may include one or more elements.

[0005] Some implementations of the methods and apparatus described herein may also include a UE for wireless communication, comprising: at least one memory; and at least one processor coupled to the at least one memory and configured to cause the UE to: send to a network entity an indication of UE capabilities including an enhanced codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission; and receive from the network entity a transmit precoding matrix indicator (TPMI) indicating a value of an enhanced precoder codebook, wherein the enhanced precoder codebook includes a precoder for each combination, wherein the phase rotation of a first antenna port relative to each of one or more of the remaining antenna ports of the UE is a multiple of 90 degrees, and the value is associated with a precoder of the enhanced precoder codebook to be used by the UE for uplink transmission.

[0006] In some implementations of the methods and devices described in this paper, the enhanced precoder codebook comprises a set of 64 vectors of length 4, as given below: , : ,and The first of the precoded vectors i The complex value in the row multiplied by the first i Input to each antenna port.

[0007] In some implementations of the methods and devices described herein, the UE also includes four antenna ports, and a set of 64 vectors of length 4 represents the corresponding allowed precoding vectors for the four antenna ports.

[0008] In some implementations of the methods and devices described herein, the TPMI received from the network entity is a seven-bit indicator.

[0009] In some implementations of the methods and devices described in this paper, 64 vectors of length 4 are used for coherent uplink transmission.

[0010] In some implementations of the methods and apparatus described herein, at least one processor is configured to cause the UE to receive from a network entity an indication that the uplink transmission from the UE is configured as a coherent single-layer transmission, and the TPMI received from the network entity is a six-bit indicator.

[0011] In some implementations of the methods and devices described in this paper, an enhanced codebook is configured for range extension of uplink communication. Attached Figure Description

[0012] Figure 1 Examples of wireless communication systems according to various aspects of this disclosure are shown.

[0013] Figure 2An example of a precoding matrix W for single-layer transmission using two antenna ports is shown.

[0014] Figure 3 An example of a precoding matrix W with enabled transform precoding is shown for single-layer transmission using four antenna ports.

[0015] Figure 4 It shows from Figure 3 An example of the sequence set obtained from the precoding matrix W.

[0016] Figure 5 An example of loss due to phase alignment error is shown using a four-antenna port codebook with a 16-phase interference encoder.

[0017] Figure 6 An example of the cumulative distribution of beamforming gain relative to the maximum achievable gain according to various aspects of this disclosure is shown.

[0018] Figure 7 An example of MIMO transmission between a UE and a NE according to various aspects of this disclosure is shown.

[0019] Figure 8 Examples of signals exchanged between the UE and NE according to various aspects of this disclosure are shown.

[0020] Figure 9 An example of a user equipment (UE) 900 according to various aspects of this disclosure is shown.

[0021] Figure 10 An example of a processor 1000 according to various aspects of this disclosure is shown.

[0022] Figure 11 An example of a network device (NE) 1100 according to various aspects of this disclosure is shown.

[0023] Figure 12 A flowchart of a method performed by a UE according to various aspects of this disclosure is shown.

[0024] Figure 13 A flowchart of a method performed by an NE according to various aspects of this disclosure is shown. Detailed Implementation

[0025] Recently, uplink coverage enhancement, or equivalent uplink range extension, has received considerable attention. This is emphasized to reduce the number of base stations required for coverage, thereby reducing the associated capital expenditures for network operators.

[0026] One approach to improving uplink coverage is to use coherent uplink multiple-input multiple-output (MIMO) with a single-layer precoder and feedback from the base station. To support this disclosure, a novel technique is used to evaluate the optimal, average, and minimum maximum beamforming gain of existing two-port and four-port phase-intervention encoders by utilizing random phase offsets between antenna ports. Random phase offsets between antenna ports are considered because there is no phase offset requirement and because phase offsets can vary over time. In the evaluation results, the relative phase between the two antennas and the relative gain between the two antennas can vary by up to 40 degrees and 4 dB, respectively, within a 20-millisecond interval from the last Sound Reference Signal (SRS) transmission.

[0027] In coherent uplink MIMO, the relative gain difference between the two antennas is usually unspecified and unknown; however, for the purpose of measuring the total radiated power (TRP), it can be assumed that both antennas are transmitting at full power. For this reason, it can also be assumed that the variation in transmit power on the two antennas is minimal.

[0028] Coherent transmission can be defined as a transmission in which the maximum difference in relative phase and power errors in a given time slot, compared to the difference measured at the time of the last SRS transmitted, is within a 20-millisecond time period, with the difference in relative phase error not exceeding 40 degrees and the difference in relative power error not exceeding 4dB.

[0029] The relative phase between the two transmitting antennas can be modeled as a gap [0, 2]. π The uniform random variable within ) . For a UE with two antenna ports, there exists only one random phase offset. For a UE with N antenna ports, there are N-1 random phase offsets to consider. For two antenna ports with a single random phase offset, Figure 2 The precoders with indices 2 to 5 in the precoding matrix W are as follows: , , , [Equation 1]

[0030] To evaluate the performance of the pre-encoder, phase can be used. The radiated power is averaged over the distribution. Alternatively, the worst-case phase can be considered. Evaluating the performance of the pre-encoder. None of these methods can be achieved through measurement because there is no method for measuring or controlling the phase between antennas in radiation testing. However, the pre-encoder is in phase... The average and worst-case performance can be analytically evaluated using power measurements for each antenna.

[0031] Below, optimal performance Optimal pre-encoder for optimal phase offset. Minimum and maximum performance. It is the best pre-encoder for worst-case phase shift. Average performance The optimal precoder is used for each phase offset, which is averaged over all possible phase offsets.

[0032] For dual-port precoders, Figure 2 Since there are only four precoders (indices 2 to 5) in the precoding matrix, the result can be obtained analytically using the following expression: , , and .

[0033] exist In this case, it becomes: optimal: average: (0.2 dB loss) Minimum maximum: (0.7 dB loss)

[0034] If passed Performance and For a comparison of performance, see [reference needed], where the relative phase offset between antenna ports has a small impact on the achievable beamforming gain.

[0035] The situation is quite different for four antenna ports. For four antenna ports, the situation is... Figure 3 The precoding matrix contains a total of 16 fully interfering encoders for single-layer transmission (indices 12 to 27). For the four antenna ports, three random phases (θ1, θ2, θ3) are used to represent the random phase offset between any two precoders. In the case of random phase offset, Figure 3 The precoder with indices 12 to 15 becomes: , , , .

[0036] Figure 3The remaining precoders at indices 16 to 27 in the precoder matrix can be represented in a similar manner. The average performance of the optimal precoder is given by averaging over the assumed random phase offset between the antenna ports as follows: [Equation 2] Where the sequence From Figure 3 The matrix is ​​used to determine, such as Figure 4 The matrix shown in the image.

[0037] The minimum maximum power on the pre-encoder set is given by the following: [Equation 3] Furthermore, the maximum power on the pre-encoder set is given by the following: [Equation 4]

[0038] The expressions in equations 2 through 4 can be numerically evaluated. In special cases, the resulting loss value is (1 dB loss) and (3 dB loss).

[0039] For the four antenna ports, the optimal precoder has an average beamforming gain 1 dB lower in phase than the optimal precoder with the best-case phase. More importantly, the optimal precoder with the worst-case phase has a beamforming gain 3 dB lower than the optimal precoder with the best-case phase. The cumulative distribution of beamforming gain relative to the maximum achievable gain is as follows: Figure 5 As shown in the image.

[0040] In embodiments of this disclosure, the UE is configured with an enhanced coherent single-layer MIMO precoder that includes all precoders, wherein the phase rotation of each antenna port relative to the first antenna port is a multiple of 90 degrees. The enhanced precoder may comprise a set of 64 vectors of length 4, given by the following equation, where the complex value in the i-th row of the precoder vector is multiplied by the input to the i-th antenna port: , :

[0041] When a UE is configured with an enhanced precoder according to embodiments of this disclosure, the power of uplink single-layer MIMO transmissions from the UE is significantly higher at the receiver. Therefore, these embodiments can be used to extend the range of UE transmissions, thereby effectively increasing cell coverage in a wireless network. The increased range can be used to facilitate uplink transmissions in low-coverage areas and to reduce the need to install additional base stations to provide sufficient coverage for a geographical area.

[0042] The various aspects of this disclosure are described in the context of wireless communication systems.

[0043] Figure 1 Examples of wireless communication systems 100 according to various aspects of this disclosure are shown. Wireless communication system 100 may include one or more NEs 102, one or more UEs 104, and a core network (CN) 106. Wireless communication system 100 may support various radio access technologies. In some implementations, wireless communication system 100 may be a 4G network, such as an LTE network or an advanced LTE (LTE-A) network. In some other implementations, wireless communication system 100 may be an NR network, such as a 5G network, an advanced 5G (5G-A) network, or a 5G ultra-wideband (5G-UWB) network. In other implementations, wireless communication system 100 may be a combination of 4G and 5G networks or other suitable radio access technologies, including IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), and IEEE 802.20. Wireless communication system 100 may support radio access technologies other than 5G, such as 6G. Additionally, the wireless communication system 100 may support technologies such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), or Code Division Multiple Access (CDMA).

[0044] One or more NEs 102 may be distributed throughout a geographic area to form a wireless communication system 100. The one or more NEs 102 described herein may be, include, or may be referred to as network nodes, base stations, network elements, network functions, network entities, radio access networks (RAN), NodeBs, eNodeBs (eNBs), next-generation NodeBs (gNBs), or other suitable terms. NEs 102 and UEs 104 may communicate via a communication link, which may be a wireless or wired connection. For example, NEs 102 and UEs 104 may perform wireless communication (e.g., receiving signaling, sending signaling) via a Uu interface.

[0045] NE 102 can provide a geographic coverage area, and NE 102 can support services for one or more UEs 104 within that geographic coverage area. For example, NE 102 and UE 104 can support wireless communication of signals associated with services (such as voice, video, packet data, messaging, broadcasting, etc.) based on one or more radio access technologies. In some implementations, NE 102 can be mobile, such as a satellite associated with a non-terrestrial network (NTN). In some implementations, different geographic coverage areas 112 associated with the same or different radio access technologies can overlap, but different geographic coverage areas can be associated with different NEs 102.

[0046] One or more UEs 104 may be distributed throughout the geographic area of ​​the wireless communication system 100. UE 104 may include or be referred to as a remote unit, mobile device, wireless device, remote device, subscriber device, transmitter device, receiver device, or some other suitable term. In some implementations, UE 104 may be referred to as a unit, station, terminal, or client, etc. Additionally or alternatively, UE 104 may be referred to as an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a Machine Type Communication (MTC) device, etc.

[0047] UE 104 may be able to support direct wireless communication with other UE 104s via a communication link. For example, UE 104 may support direct wireless communication with another UE 104 via a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular V2X deployments, this communication link 114 may be referred to as a sidelink. For example, UE 104 may support direct wireless communication with another UE 104 via a PC5 interface.

[0048] NE 102 can support communication with CN 106 or with another NE 102, or both. For example, NE 102 can interface with another NE 102 or CN 106 via one or more backhaul links (e.g., S1, N2, N2, or network interfaces). In some implementations, NE 102 can communicate directly with each other. In some other implementations, NE 102 can communicate with each other or indirectly (e.g., via CN 106). In some implementations, one or more NE 102 may include sub-components, such as access network entities, which may be examples of access node controllers (ANCs). The ANC can communicate with one or more UEs 104 via one or more other access network transport entities, which may be referred to as radio heads, smart radio heads, or transmit-receive points (TRPs).

[0049] CN 106 can support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. CN 106 can be an evolved packet core (EPC) or a 5G core (5GC), which may include control plane entities that manage access and mobility (e.g., Mobility Management Entity (MME), Access and Mobility Management Functions (AMF)) and user plane entities that route packets or interconnects to external networks (e.g., Serving Gateway (S-GW), Packet Data Network (PDN) Gateway (P-GW), or User Plane Function (UPF)). In some implementations, the control plane entities may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signaling bearers, etc.) for one or more UEs 104 served by one or more NEs 102 associated with CN 106.

[0050] CN 106 can communicate with the packet data network via one or more backhaul links 116 (e.g., via S1, N2, N2, or another network interface). The packet data network may include an application server. In some implementations, one or more UEs 104 can communicate with the application server. UE 104 can establish a session with CN 106 (e.g., a Protocol Data Unit (PDU) session, etc.) via NE 102. CN 106 can use the established session (e.g., an established PDU session) to route services (e.g., control information, data, etc.) between UE 104 and the application server. The PDU session may be an example of a logical connection between UE 104 and CN 106 (e.g., one or more network functions of CN 106).

[0051] In the wireless communication system 100, NE 102 and UE 104 can use the resources of the wireless communication system 100 (such as time resources (e.g., symbols, time slots, subframes, frames, etc.) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communication). In some implementations, NE 102 and UE 104 can support different resource structures. For example, NE 102 and UE 104 can support different frame structures. In some implementations, such as in 4G, NE 102 and UE 104 can support a single frame structure. In some other implementations, such as in 5G and other suitable radio access technologies, NE 102 and UE 104 can support various frame structures (i.e., multiple frame structures). NE 102 and UE 104 can support various frame structures based on one or more digital technologies.

[0052] One or more digital technologies may be supported in the wireless communication system 100, and the digital technologies may include subcarrier spacing and cyclic prefix. A first digital technology (e.g., =0) can be associated with the first subcarrier spacing (e.g., 15 kHz) and the normal cyclic prefix. In some implementations, the first digital technique (e.g., ...) associated with the first subcarrier spacing (e.g., 15 kHz) is... =0) can utilize one time slot per subframe. Second digital technologies (e.g., =1) can be associated with the second subcarrier spacing (e.g., 30 kHz) and the normal cyclic prefix. The third digital technology (e.g., =2) can be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth digital technology (e.g., =3) can be associated with the fourth subcarrier spacing (e.g., 120 kHz) and the ordinary cyclic prefix. The fifth digital technology (e.g., =4) can be associated with the fifth subcarrier spacing (e.g., 240 kHz) and the normal cyclic prefix.

[0053] Time intervals for resources (such as communication resources) can be organized according to frames (also called radio frames). Each frame can have a duration, such as 10 milliseconds (ms). In some implementations, each frame can include multiple subframes. For example, each frame can include 10 subframes, and each subframe can have a duration, such as 1 ms. In some implementations, each frame can have the same duration. In some implementations, each subframe of a frame can have the same duration.

[0054] Alternatively or concurrently, time intervals of resources (e.g., communication resources) can be organized according to time slots. For example, a subframe may include multiple (e.g., a large number) time slots. The number of time slots in each subframe may also depend on one or more digital technologies supported in the wireless communication system 100. For example, a first digital technology, a second digital technology, a third digital technology, a fourth digital technology, and a fifth digital technology (i.e., ...) associated with corresponding subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz. =0、 =1、 =2、 =3、 =4) A single time slot per subframe, two time slots per subframe, four time slots per subframe, eight time slots per subframe, and 16 time slots per subframe can be utilized, respectively. Each time slot can include multiple (e.g., a large number) symbols (e.g., OFDM symbols). In some implementations, the number of time slots (e.g., quantity) for a subframe can depend on the digital technique. For a normal cyclic prefix, a time slot can include 14 symbols. For an extended cyclic prefix (e.g., for a subcarrier spacing of 60 kHz), a time slot can include 12 symbols. The relationship between the number of symbols per time slot, the number of time slots per subframe, and the number of time slots per frame for both normal and extended cyclic prefixes can depend on the digital technique. It should be understood that the first digital technique (e.g., quantity) associated with the first subcarrier spacing (e.g., 15 kHz) is different. The reference of (=0) can be used interchangeably between subframes and time slots.

[0055] In the wireless communication system 100, the electromagnetic (EM) spectrum can be divided into various categories, frequency bands, frequency channels, etc., based on frequency or wavelength. By way of example, the wireless communication system 100 can support one or more operating frequency bands, such as frequency ranges specified as FR1 (410 MHz to 7.125 GHz), FR2 (24.25 GHz to 52.6 GHz), FR3 (7.125 GHz to 24.25 GHz), FR4 (52.6 GHz to 114.25 GHz), FR4a or FR4-1 (52.6 GHz to 71 GHz), and FR5 (114.25 GHz to 300 GHz). In some implementations, NE 102 and UE 104 can perform wireless communication on one or more operating frequency bands. In some implementations, FR1 can be used by NE 102 and UE 104, along with other devices or apparatuses, for cellular communication services (e.g., control information, data). In some implementations, FR2 can be used by NE 102 and UE 104, as well as other devices or apparatuses, for short-range, high data rate capabilities.

[0056] FR1 can be associated with one or more digital technologies (e.g., at least three digital technologies). For example, FR1 can be associated with the following: a first digital technology (e.g., =0), which includes a 15 kHz subcarrier spacing; second digital technology (e.g., =1), which includes a 30 kHz subcarrier spacing; and a third digital technology (e.g., =2), which includes a subcarrier spacing of 60 kHz. FR2 can be associated with one or more digital technologies (e.g., at least two digital technologies). For example, FR2 can be associated with a third digital technology (e.g., =2), which includes a 60 kHz subcarrier spacing; and a fourth digital technology (e.g., =3), which includes a subcarrier spacing of 120 kHz.

[0057] Figure 7 An example of MIMO transmission between UE 102 and NE 104 is shown, and Figure 8 Examples of signals exchanged between the UE and NE according to various aspects of this disclosure are shown. Figure 7 In the example, UE 102 implements a precoder for RF signals transmitted from four transmit antennas P1 to P4. UE 102 implementing the enhanced precoder codebook of embodiments of this disclosure may have two transmit antennas, four transmit antennas, or more than four transmit antennas. RF signals are transmitted to NE 104, which receives signals from antennas P1 to PN at one or more receive antennas.

[0058] The precoded transmission 814 from the UE can be a single-layer or rank-one transmission, where each resource element (RE) transmits one symbol. In an embodiment, the UE is configured for beamforming and transmits the same information by multiple antennas of the UE. The transmitted beams interact with each other to cause constructive or destructive interference. The beams constructively interfere with each other at the receiver when optimally aligned. Boosting the signal effectively increases the UE's transmission range, which also increases the effective size of the cell (e.g., when the cell area is defined by a 3dB drop in signal strength).

[0059] Due to the physical characteristics of the circuitry, the UE is unaware of the phase of the transmitted RF signal. Therefore, in step 812, the UE precodes the antenna application based on feedback from the reference signal 806 sent to the receiver. The precoded values ​​are typically applied relative to the reference antenna. For example, the reference antenna may have static phase orientation, and precoding may be applied to the remaining antennas to produce the highest signal power at the receiver.

[0060] A drawback of a conventional codebook design for four antenna ports is that, depending on the relative phase of the signal received at the base station and the random phase offset between the antenna ports, there may not be any precoder that can effectively align the phase at the receiver.

[0061] In embodiments of this disclosure, the precoder takes the form of: , : It is included in the set of precoders defined for two-port transmission. Using this set, it is possible to align the phase of the second antenna observed at the receiver with the phase of the first antenna within 45 degrees.

[0062] To align the phases of the second, third, and fourth antennas observed at the receiver within 45 degrees of the phase of the first antenna, embodiments may use 64 pre-encoders. In some embodiments, the set may be expressed as: , : [Equation 5] in Indicates less than or equal to The largest integer, where j represents the square root of -1 ( ), and is a complex number as known in the art for rotating phase. In this embodiment, the 64 precoders can each represent a combination of phases spaced 90 degrees apart for the three antenna ports relative to the first antenna port.

[0063] Alternatively, the precoder set can be expressed as: , , , : , , [Equation 6]

[0064] For the precoder sets in Equations 5 and 6, the expressions in Equations 2 to 4 above can be numerically evaluated. In special cases, the loss value is (0.4dB loss) and (0.8 dB loss).

[0065] For the four antenna ports with the precoder set in equations (5) and (6), the optimal precoder has an average beamforming gain 0.4 dB lower in phase than the optimal precoder with the best-case phase. Importantly, in this embodiment, the beamforming gain of the optimal precoder with the worst-case phase is only 0.8 dB worse than that of the optimal precoder with the best-case phase. Figure 6 An example of the cumulative distribution of beamforming gain relative to the maximum achievable gain according to an embodiment of the present disclosure is shown.

[0066] Therefore, for the enhanced precoder codebook according to the embodiment, the loss due to worst-case phase alignment error is reduced from 3 dB to 0.8 dB, and the average loss is reduced from 1 dB to 0.4 dB. For cases where coverage and range are critical, the benefits of implementing the enhanced precoder codebook at the UE for four antenna ports are substantial.

[0067] To accommodate additional phase configurations, and Figure 3 Compared to the 28 precoders shown, the enhanced precoder codebook can include at least 75 precoders. In some embodiments, seven bits can be used to represent all values ​​in the codebook to indicate the values ​​of the enhanced precoder codebook.

[0068] By limiting the precoder selection to fully coherent single-layer precoders in the codebook, the number of bits used to indicate codebook values ​​can be reduced, which can be represented by a six-bit indication. Therefore, in some embodiments, indication 804 is sent to the UE to limit the precoders available for selection to fully coherent single-layer precoders, thereby reducing the signaling overhead used to indicate the value of the enhanced precoder.

[0069] Enhanced precoder codebooks can be used to extend the range of uplink communications. In some embodiments, the UE may include both a traditional codebook and an enhanced precoder codebook, with the enhanced precoder codebook used for communications requiring enhanced range. For example, the network may determine that the UE's coverage is limited and configure range extension, which includes using an enhanced precoder codebook and single-layer transport at the UE. Therefore, the network can selectively implement the enhanced precoder codebook to extend the range of uplink communications.

[0070] Figure 9 An example of a UE 900 according to various aspects of this disclosure is shown. The UE 900 may include a processor 902, a memory 904, a controller 906, and a transceiver 908. The processor 902, memory 904, controller 906, or transceiver 908, or various combinations thereof, or various components thereof, may be examples of parts for performing the various aspects of this disclosure as described herein. These components may be coupled via one or more interfaces (e.g., operatively, communicatively, functionally, electronically, electrically).

[0071] Processor 902, memory 904, controller 906, or transceiver 908, or various combinations or components thereof, may be implemented in hardware (e.g., circuitry). Hardware may include a processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured or otherwise supporting components for performing the functions described in this disclosure.

[0072] Processor 902 may include intelligent hardware devices (e.g., a general-purpose processor, DSP, CPU, ASIC, FPGA, or any combination thereof). In some implementations, processor 902 may be configured to operate memory 904. In some other implementations, memory 904 may be integrated into processor 902. Processor 902 may be configured to execute computer-readable instructions stored in memory 904 to cause UE 900 to perform various functions of this disclosure.

[0073] Memory 904 may include volatile or non-volatile memory. Memory 904 may store computer-readable, computer-executable code, including instructions that, when executed by processor 902, cause UE 900 to perform the various functions described herein. The code may be stored in a non-transient computer-readable medium (e.g., memory 904 or another type of memory). Computer-readable media include non-transient computer storage media and communication media, including any medium that facilitates the transfer of computer programs from one place to another. Non-transient storage media may be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0074] In some implementations, processor 902 and memory 904 coupled to processor 902 may be configured to cause UE 900 to perform one or more of the functions described herein (e.g., instructions stored in memory 904 are executed by processor 902). For example, according to the examples disclosed herein, processor 902 may support wireless communication at UE 900. UE 900 may be configured to support components for transmitting to a network entity an indication of UE capabilities including an enhanced precoder codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission and receiving from the network entity a transmit precoder matrix indicator (TPMI) indicating the value of the enhanced precoder codebook.

[0075] Controller 906 can manage input and output signals for UE 900. Controller 906 can also manage peripheral devices not integrated into UE 900. In some implementations, controller 906 can utilize an operating system such as iOS®, Android®, Windows®, or other operating systems. In some implementations, controller 906 can be implemented as part of processor 902.

[0076] In some implementations, UE 900 may include at least one transceiver 908. In some other implementations, UE 900 may have more than one transceiver 908. Transceiver 908 may represent a wireless transceiver. Transceiver 908 may include one or more receiver chains 910, one or more transmitter chains 912, or a combination thereof.

[0077] Receiver chain 910 can be configured to receive signals (e.g., control information, data, packets) via a wireless medium. For example, receiver chain 910 may include one or more antennas to receive signals over the air or via a wireless medium. Receiver chain 910 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. Receiver chain 910 may include at least one demodulator configured to demodulate the received signal and obtain transmitted data by reversing the modulation technique applied during signal transmission. Receiver chain 910 may include at least one decoder for decoding the processed demodulated signal to receive the transmitted data.

[0078] Transmitter chain 912 can be configured to generate and transmit signals (e.g., control information, data, packets). Transmitter chain 912 may include at least one modulator for modulating data onto a carrier signal, thereby preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes such as phase shift keying (PSK) or quadrature amplitude modulation (QAM). Transmitter chain 912 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. Transmitter chain 912 may also include one or more antennas for transmitting the amplified signal over the air or wireless medium.

[0079] Figure 10 An example of a processor 1000 according to various aspects of this disclosure is shown. The processor 1000 may be an example of a processor configured to perform various operations according to the examples described herein. The processor 1000 may include a controller 1002 configured to perform various operations according to the examples described herein. The processor 1000 may optionally include at least one memory 1004, such as an L1 / L2 / L3 cache. Additionally or alternatively, the processor 1000 may optionally include one or more arithmetic logic units (ALUs) 1006. One or more of these components may be electronically communicated or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0080] Processor 1000 may be a processor chipset and includes a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receive, acquire, retrieve, send, output, forward, store, determine, identify, access, write, read) according to examples described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory native to the processor chipset (e.g., processor 1000) or included in the processor chipset), or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), etc.).

[0081] Controller 1002 can be configured to manage and coordinate various operations of processor 1000 (e.g., signaling, receiving, acquiring, retrieving, sending, outputting, forwarding, storing, determining, identifying, accessing, writing, and reading) to enable processor 1000 to support various operations according to examples described herein. For example, controller 1002 can operate as a control unit of processor 1000, thereby generating control signals that manage the operation of various components of processor 1000. These control signals include enabling or disabling functional units, selecting data paths, initiating memory accesses, and coordinating the timing of operations.

[0082] Controller 1002 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from memory 1004 and determine subsequent instructions(s) to be executed to enable processor 1000 to support various operations according to examples described herein. Controller 1002 may be configured to track the memory addresses of instructions associated with memory 1004. Controller 1002 may be configured to decode instructions to determine the operations to be performed and the operands involved. For example, controller 1002 may be configured to interpret instructions and determine control signals to be output to other components of processor 1000 to enable processor 1000 to support various operations according to examples described herein. Additionally or alternatively, controller 1002 may be configured to manage data flow within processor 1000. Controller 1002 may be configured to control data transfers between registers, arithmetic logic unit (ALU), and other functional units of processor 1000.

[0083] Memory 1004 may include one or more caches (e.g., memory local to processor 1000 or included in processor 1000, or other memory such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc.). In some implementations, memory 1004 may reside within or on the processor chipset (e.g., locally to processor 1000). In some other implementations, memory 1004 may reside outside the processor chipset (e.g., remotely from processor 1000).

[0084] Memory 1004 may store computer-readable, computer-executable code, including instructions that, when executed by processor 1000, cause processor 1000 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as system memory or another type of memory. Controller 1002 and / or processor 1000 may be configured to execute the computer-readable instructions stored in memory 1004 to cause processor 1000 to perform various functions. For example, processor 1000 and / or controller 1002 may be coupled to or connected to memory 1004, processor 1000, and controller 1002, and memory 1004 may be configured to perform the various functions described herein. In some examples, processor 1000 may include multiple processors, and memory 1004 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may be configured individually or collectively to perform the various functions described herein.

[0085] One or more ALUs 1006 can be configured to support various operations according to the examples described herein. In some implementations, one or more ALUs 1006 may reside within or on a processor chipset (e.g., processor 1000). In some other implementations, one or more ALUs 1006 may reside outside the processor chipset (e.g., processor 1000). One or more ALUs 1006 can perform one or more computations on data, such as addition, subtraction, multiplication, and division. For example, one or more ALUs 1006 can receive input operands and an opcode that determines the operation to be performed. One or more ALUs 1006 are configured to have various logic and arithmetic circuitry, including adders, subtractors, shifters, and logic gates, to process and manipulate data according to the operations. Additionally or alternatively, one or more ALU 1006 may support logical operations such as AND, OR, XOR, NOR, and NAND, enabling one or more ALU 1006 to handle conditional operations, comparisons, and bitwise operations.

[0086] Based on the examples disclosed herein, processor 1000 may support wireless communication. Processor 1000 may be configured or operable to support: components for transmitting to a network entity an indication of UE capabilities including an enhanced precoder codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission, and receiving from the network entity a transmit precoder matrix indicator (TPMI) indicating the value of the enhanced precoder codebook.

[0087] Figure 11 An example of an NE 1000 according to various aspects of this disclosure is shown. The NE 1100 may include a processor 1102, a memory 1104, a controller 1106, and a transceiver 1108. The processor 1102, memory 1104, controller 1106, or transceiver 1108, or various combinations thereof, or various components thereof, may be examples of parts for performing the various aspects of this disclosure as described herein. These components may be coupled via one or more interfaces (e.g., operatively, communicatively, functionally, electronically, electrically).

[0088] Processor 1102, memory 1104, controller 1106, or transceiver 1108, or various combinations or components thereof, may be implemented in hardware (e.g., circuitry). Hardware may include a processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), or other programmable logic device, or any combination of components configured or otherwise supporting the performance of the functions described in this disclosure.

[0089] Processor 1102 may include intelligent hardware devices (e.g., a general-purpose processor, DSP, CPU, ASIC, FPGA, or any combination thereof). In some implementations, processor 1102 may be configured to operate memory 1104. In some other implementations, memory 1104 may be integrated into processor 1102. Processor 1102 may be configured to execute computer-readable instructions stored in memory 1104 to cause NE 1100 to perform various functions of this disclosure.

[0090] Memory 1104 may include volatile or non-volatile memory. Memory 1104 may store computer-readable, computer-executable code, including instructions that, when executed by processor 1102, cause NE 1100 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as memory 1104 or another type of memory. Computer-readable media include non-transitory computer storage media and communication media, including any medium that facilitates the transfer of computer programs from one place to another. Non-transitory storage media may be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0091] In some implementations, processor 1102 and memory 1104 coupled to processor 1102 may be configured to cause NE 1100 to perform one or more of the functions described herein (e.g., instructions stored in memory 1104 are executed by processor 1102). For example, according to the examples disclosed herein, processor 1102 may support wireless communication at NE 1100. NE 1100 may be configured to support components for receiving from the UE an indication of UE capabilities including an enhanced precoder codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission and for sending to the UE a transmit precoding matrix indicator (TPMI) indicating the value of the enhanced precoder codebook.

[0092] Controller 1106 can manage the input and output signals of NE 1100. Controller 1106 can also manage peripheral devices not integrated into NE 1100. In some implementations, controller 1106 can utilize an operating system such as iOS®, Android®, Windows®, or other operating systems. In some implementations, controller 1106 can be implemented as part of processor 1102.

[0093] In some implementations, NE 1100 may include at least one transceiver 1108. In other implementations, NE 1100 may have more than one transceiver 1108. Transceiver 1108 may represent a wireless transceiver. Transceiver 1108 may include one or more receiver chains 1110, one or more transmitter chains 1112, or a combination thereof.

[0094] Receiver chain 1110 can be configured to receive signals (e.g., control information, data, packets) via a wireless medium. For example, receiver chain 1110 may include one or more antennas for receiving signals over the air or via a wireless medium. Receiver chain 1110 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. Receiver chain 1110 may include at least one demodulator configured to demodulate the received signal and obtain the transmitted data by reversing the modulation technique applied during signal transmission. Receiver chain 1110 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

[0095] Transmitter chain 1112 can be configured to generate and transmit signals (e.g., control information, data, packets). Transmitter chain 1112 may include at least one modulator for modulating data onto a carrier signal, thereby preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes such as phase shift keying (PSK) or quadrature amplitude modulation (QAM). Transmitter chain 1112 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. Transmitter chain 1112 may also include one or more antennas for transmitting the amplified signal over the air or wireless medium.

[0096] Figure 8 Examples of the operation of the UE and NE according to various aspects of this disclosure are shown. Figure 8 The operation is shown as a signal diagram, which shows the signals exchanged between the UE and NE and some operations performed by these entities.

[0097] Figure 12 A flowchart of a method according to various aspects of this disclosure is shown. The operation of this method can be implemented by a UE, as described herein. In some implementations, the UE can execute a set of instructions to control the functional elements of the UE to perform the described functions.

[0098] At 1202, the method may include sending an indication 802 to the NE that the UE's capabilities include an enhanced codebook. The operation of 1202 can be performed according to the examples described herein. In some implementations, aspects of the operation of 1202 may be determined by reference to [reference needed]. Figure 9 The described UE is used to execute.

[0099] In an embodiment, the UE informs the NE that the UE capability includes an enhanced codebook with a pre-encoder for each combination, wherein the phase rotation of each antenna port of the UE relative to the first antenna port is a multiple of 90 degrees. The pre-encoder may include a set of 64 vectors of length 4 given below: , : ,and The first of the precoded vectors i The complex value in the row multiplied by the first i The input to each antenna port. Using MAC layer signaling, such as by sending a Radio Resource Control (RRC) message, the UE can notify the NE of this capability. In some embodiments, the UE may send an indication to the NE in response to a query from the NE in 1202, but in other embodiments, the UE may simply signal the capability without prompting from the NE.

[0100] At 1204, the method may include an indication 804 that the MIMO uplink transmission received from the NE is limited to single-layer transmission. The operation of 1204 can be performed according to the examples described herein. In some implementations, aspects of the operation of 1204 may be determined by reference to... Figure 9 The described UE is used to execute.

[0101] In some embodiments, considering all entries in the enhanced codebook, the number of bits used to indicate the value in the enhanced codebook is seven bits. However, when the entries are limited to those used for coherent single-layer transmission, the number of entries is lower, and a six-bit indication can be used for encoding. Therefore, when the UE receives an indication 804 at 1204 from the NE that the associated uplink MIMO transmission will be a coherent single-layer transmission, the number of bits used to indicate the enhanced codebook value can be reduced.

[0102] At 1206, the method may include sending a reference signal 806 to the NE. The operation of 1206 can be performed according to examples as described herein. In some implementations, aspects of the operation of 1206 may be determined by reference... Figure 9 The described UE is used to execute.

[0103] The reference signal 806 sent to the NE can be a sounding reference signal (SRS). The UE can send the SRS from each active antenna port, and this SRS will be used for subsequent MIMO uplink transmissions. In some embodiments, the reference signal can be sent simultaneously on different frequency resources to avoid interference between signals, for example, by using different subcarriers. In another embodiment, the signals are interleaved. The specific mode of reference signal transmission can be configured by the base station via RRC messages (e.g., RRCSetup, RRCReconfiguration), as is known in the art.

[0104] At 1208, the method may include receiving a Transmit Precoding Matrix Indicator (TPMI) 810 from a network entity. The operation of 1208 can be performed according to examples as described herein. In some implementations, aspects of the operation of 1208 may be determined by reference to [reference needed]. Figure 9 The described UE is used to execute.

[0105] The TPMI received at 1208 can indicate a value in the enhanced codebook. As mentioned above, in various embodiments, the TPMI can be a six-bit or seven-bit indication corresponding to a specific value in the enhanced precoder codebook.

[0106] At 1210, the method may include applying a precoding vector associated with the TPMI value 810 received from the NE. The operation at 1210 can be performed according to examples as described herein. In some implementations, aspects of the operation at 1210 may be derived from, as referenced... Figure 9 The UE described is used for execution. Specifically, the UE can apply precoding vectors from the enhanced precoding codebook to... Figure 7 The four antenna ports P1 to P4. An example of applying precoding associated with TPMI values ​​is as follows: Figure 8 The element 812 is shown.

[0107] At 1212, the method may include transmitting an uplink MIMO signal 814 using a precoding vector associated with a precoding index of an enhanced precoding codebook indicated by TPMI received from the NE. The operation of 1212 can be performed according to examples as described herein. In some implementations, aspects of the operation of 1212 may be defined by reference to... Figure 9 The UE described is used to perform this. By using precoder values ​​in the enhanced precoder codebook, MIMO transmission 814 can be a four-port single-layer transmission with a substantially extended range.

[0108] It should be noted that the methods described in this paper describe possible implementations, and the operations and steps can be rearranged or otherwise modified, and other implementations are possible.

[0109] Figure 13 A flowchart of a method according to various aspects of this disclosure is shown. The operation of this method can be implemented by a NE, as described herein. In some implementations, the NE can execute a set of instructions to control the functional elements of the NE to perform the described functions.

[0110] At 1302, the method may include receiving from the UE an indication 802 that the UE's capabilities include an enhanced precoder codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission. The operation of 1302 can be performed according to examples as described herein. In some implementations, aspects of the operation of 1302 may be determined by reference to... Figure 10 The NE described is used to execute.

[0111] In an embodiment, the UE informs the NE that the UE capability includes an enhanced codebook with a pre-encoder for each combination, wherein the phase rotation of each antenna port of the UE relative to the first antenna port is a multiple of 90 degrees. The pre-encoder may include a set of 64 vectors of length 4 given below: , : ,and The first of the precoded vectorsi The complex value in the row multiplied by the first i The input to each antenna port. The UE can notify the NE of this capability using MAC layer signaling, and there are no particular restrictions on the specific MAC signal. In some embodiments, the NE can receive an indication from the UE in response to a query from the NE at 1202, but in other embodiments, the UE can signal the capability without prompting from the NE.

[0112] At 1304, the method may include sending an indication 804 to the UE that the MIMO uplink transmission is limited to single-layer transmission. The operation of 1304 can be performed according to the examples described herein. In some implementations, aspects of the operation of 1304 may be determined by reference to... Figure 10 The NE described is used to execute.

[0113] In some embodiments, the number of bits used to indicate values ​​in the enhanced codebook is seven, taking into account all entries in the enhanced codebook. However, when entries are limited to those used for coherent single-layer transmission, the number of entries is lower, and a six-bit indication can be used for encoding. Therefore, when the NE provides the UE at 1304 with an indication that the associated uplink MIMO transmission will be a coherent single-layer transmission, the number of bits used to indicate the enhanced codebook values ​​can be reduced.

[0114] At 1306, the method may include receiving a reference signal 806 from the UE. The operation of 1306 can be performed according to examples as described herein. In some implementations, aspects of the operation of 1306 may be determined by reference... Figure 10 The NE described is used to execute.

[0115] The reference signal 806 received by the NE can be a sounding reference signal (SRS). The NE can receive the SRS from each active antenna port of the UE, and this SRS will be used for subsequent MIMO uplink transmissions. In some embodiments, the reference signal can be transmitted simultaneously on different frequency resources to avoid interference between signals, for example, by using different subcarriers. In another embodiment, the signals are interleaved. The specific mode of reference signal transmission can be configured by the base station via RRC messages (e.g., RRCSetup, RRCReconfiguration), as is known in the art.

[0116] At 1308, the method may include measuring the reference signal received by the UE in 1306. The operation of 1308 can be performed according to examples as described herein. In some implementations, aspects of the operation of 1308 may be determined by reference... Figure 10 The NE described is used for execution. An example of measuring the reference signal is as follows: Figure 8 The element 808 is displayed.

[0117] After receiving the reference signal from the UE, the NE measures and analyzes the received signal. The NE can estimate the channel state information (CSI) by comparing the received SRS with the known reference signal. The NE can evaluate various parameters, such as path loss, propagation delay (phase delay), and received signal strength, to understand the current radio environment and channel conditions between the NE and the UE.

[0118] In an embodiment, the NE measures the phase of at least one reference signal from each antenna port of the UE, determines the optimal combination of phase offsets to be applied to the respective antenna ports, and identifies the value of the enhancement precoder codebook that best matches the optimal combination of phase offsets. The optimal combination of phase offsets may be a combination of phase offsets that maximizes the signal strength transmitted from the associated antenna port of the UE.

[0119] At 1310, the method may include sending a Transmit Precoding Matrix Indicator (TPMI) 810 from a network entity. The operation of 1310 can be performed according to examples as described herein. In some implementations, aspects of the operation of 1310 may be determined by reference to [reference needed]. Figure 10 The NE described is used to execute.

[0120] The TPMI 810 transmitted at 1310 can indicate a value in the enhanced codebook. As mentioned above, in various embodiments, the TPMI can be a six-bit or seven-bit indication corresponding to a specific antenna configuration in the enhanced precoder codebook.

[0121] At 1312, the method may include receiving uplink MIMO signal 814 using a precoding vector associated with a precoding value of an enhanced precoding codebook indicated by TPMI from the UE. The operation of 1312 can be performed according to examples as described herein. In some implementations, aspects of the operation of 1312 may be derived from references... Figure 10 The NE described is used to execute.

[0122] It should be noted that the methods described in this paper describe possible implementations, and the operations and steps can be rearranged or otherwise modified, and other implementations are possible.

[0123] The description provided herein is intended to enable those skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and other variations may be applied to the general principles defined herein without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A user equipment (UE) for wireless communication, comprising: At least one memory; as well as At least one processor, coupled to the at least one memory and configured to cause the UE to: Sending an indication to a network entity indicating UE capabilities, said UE capabilities including an enhanced precoder codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission; and Receive from the network entity a Transmit Precoding Matrix Indicator (TPMI) indicating the value of the enhanced precoder codebook. The enhanced precoder codebook includes a precoder for each combination, wherein the phase rotation of the first antenna port of the UE relative to each of the one or more remaining antenna ports is a multiple of 90 degrees, and the value is associated with the precoder of the enhanced precoder codebook to be used by the UE for uplink transmission.

2. The UE of claim 1, wherein the enhanced precoder codebook comprises a set of 64 vectors of length 4 given below: , : , and wherein the complex value in the m-th row of the precoding vector is multiplied with the input to the m-th antenna port. i wherein the complex value in the m-th row of the precoding vector is multiplied with the input to the m-th antenna port. i wherein the complex value in the m-th row of the precoding vector is multiplied with 3. The UE of claim 2, wherein the UE further comprises four antenna ports, and the set of 64 vectors of length 4 represents the corresponding allowed precoding vectors for the four antenna ports.

4. The UE of claim 2, wherein the TPMI received from the network entity is a seven-bit indicator.

5. The UE according to claim 2, wherein the 64 vectors of length 4 are used for coherent uplink transmission.

6. The UE of claim 1, wherein the at least one processor is configured to cause the UE to: Receive an instruction from the network entity to configure uplink transmissions from the UE as coherent single-layer transmissions. The TPMI received from the network entity is a six-bit indicator.

7. The UE of claim 1, wherein the enhanced precoder codebook is configured for range extension of uplink communication.

8. A processor for user equipment (UE) for wireless communication with a network entity, the processor comprising: At least one controller, coupled to at least one memory, and configured to cause the processor to: Send an indication to the network entity indicating UE capabilities, including an enhanced precoder codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission; and Receive from the network entity a Transmit Precoding Matrix Indicator (TPMI) indicating the value of the enhanced precoder codebook. The enhanced precoder codebook includes a precoder for each combination, wherein the phase rotation of the first antenna port relative to each of one or more remaining antenna ports of the UE is a multiple of 90 degrees, and the value is associated with the precoder of the enhanced precoder codebook to be used by the UE for uplink transmission.

9. The processor of claim 8, wherein the enhanced precoder codebook comprises a set of 64 vectors of length 4 given below: , : and The first of the precoded vectors i The complex value in the row is multiplied by the first... i Input to each antenna port.

10. The processor of claim 9, wherein the UE further comprises four antenna ports, and the set of 64 vectors of length 4 represents a corresponding allowed precoding vector for the four antenna ports.

11. The processor of claim 9, wherein the TPMI received from the network entity is a seven-bit indicator.

12. The processor of claim 9, wherein the 64 vectors of length 4 are used for coherent uplink transmission.

13. The processor of claim 8, wherein the at least one controller is configured to cause the processor to: Receive an instruction from the network entity to configure uplink transmissions from the UE as coherent single-layer transmissions. The TPMI received from the network entity is a six-bit indicator.

14. The processor of claim 8, wherein the enhanced precoder codebook is configured for range extension of uplink communication.

15. A method performed by a user equipment (UE), the method comprising: Send an indication to a network entity indicating UE capabilities, including an enhanced precoder codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission; as well as Receive from the network entity a Transmit Precoding Matrix Indicator (TPMI) indicating the value of the enhanced precoder codebook. The enhanced precoder codebook includes a precoder for each combination, wherein the phase rotation of the first antenna port relative to each of one or more remaining antenna ports of the UE is a multiple of 90 degrees, and the value is associated with the precoder of the enhanced precoder codebook to be used by the UE for uplink transmission.

16. The method of claim 15, wherein the enhanced precoder codebook comprises a set of 64 vectors of length 4 given below: , : ,and The first of the precoded vectors i The complex value in the row is multiplied by the first... i Input to each antenna port.

17. The method of claim 16, wherein the UE further comprises four antenna ports, and the set of 64 vectors of length 4 represents a corresponding permitted precoding vector for the four antenna ports.

18. A base station for wireless communication, comprising: At least one memory; as well as At least one processor, coupled to the at least one memory, and configured to cause the base station to: Receive an indication from the user equipment (UE) indicating UE capabilities, including an enhanced precoder codebook for single-layer uplink multiple-input multiple-output (MIMO) transmission; as well as Send a Transmit Precoding Matrix Indicator (TPMI) to the UE, indicating the value of the enhanced precoder codebook. The enhanced precoder codebook includes a precoder for each combination, wherein the phase rotation of the first antenna port relative to each of one or more remaining antenna ports of the UE is a multiple of 90 degrees, and the value is associated with the precoder of the enhanced precoder codebook to be used by the UE for uplink transmission.

19. The base station of claim 18, wherein the enhanced precoder codebook comprises a set of 64 vectors of length 4 given below: , : ,and The first of the precoded vectors i The complex value in the row is multiplied by the first... i Input to each antenna port.

20. The base station of claim 18, wherein the at least one processor is configured to cause the base station to: Send an instruction to the UE to configure the uplink transmission from the UE as single-layer transmission. The TPMI sent to the UE is a six-bit indicator.

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