Nonlinear Precoding for Multi-User Multiple-Input Multiple-Output

Abstract

Methods, systems, and devices for wireless communication are described. A base station may associate a first port and a second port with respective sets of antenna elements based on a first linear precoding vector and a second linear precoding vector, where the phases of the ports are coherent. The base station may generate coefficients indicating first and second combinations of a first data set for a first user equipment (UE) and a second data set for a second UE. In some cases, the base station may apply the first linear precoding vector to the first combination, apply the second linear precoding vector to the second combination, and transmit the first combination to the first UE using a first transmission beam corresponding to the first port and transmit the second combination to the second UE using a second transmission beam corresponding to the second port.

Description

[0001] Cross-reference

[0002] This patent application claims the benefit of U.S. Patent Application No. 17 / 537,327, titled "NON-LINEAR PRECODING FOR MULTI-USER MULTIPLE-INPUT MULTIPLE-OUTPUT," filed on November 29, 2021, by NAMGOONG et al., which is assigned to the assignee of the present application. Technical Field

[0003] The following relates to wireless communication, including non-linear precoding for multi-user (MU) multiple-input multiple-output (MIMO) communication. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, and so on. These systems may be able to support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multi-access systems include fourth-generation (4G) systems (such as Long-Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems) and fifth-generation (5G) systems (which may be referred to as New Radio (NR) systems). These systems may employ techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multi-access communication system may include one or more base stations or one or more network access nodes, each of which simultaneously supports communication for multiple communication devices, which may also be referred to as user equipment (UE). Summary of the Invention

[0005] The described techniques relate to improved methods, systems, devices, and apparatus for supporting non-linear precoding for multi-user (MU) multiple-input multiple-output (MIMO) communication. Generally, the described techniques provide a base station with an enhanced precoding scheme for shared channel data transmission to two user equipment (UEs). In some cases, the described techniques can increase the received signal power for transmission to a second UE as the base station can transmit data to a first UE under low signal-to-noise ratio (SNR) conditions. The base station can associate a first port for shared channel transmission with a set of antenna elements of an antenna array and associate a second port for shared channel transmission with the set of antenna elements of the antenna array. The first port can have a first phase and can be based on a first linear precoding vector, and the second port can be based on a second linear precoding vector and a phase shift such that the second port can have a second phase coherent with the first phase. That is, the base station can apply linear precoding to generate constructive interference transmissions via the first port and the second port.

[0006] In some examples, the base station can use the first port and the second port to transmit data associated with a first UE and a second UE. For example, the base station can use the first port to transmit a linear combination of a first data set for the first UE and a second data set for the second UE to the first UE and the second UE. The base station can use the second port to transmit a different linear combination of the first data set and the second data set to the second UE. In some examples, the linear combinations of the first data set and the second data set can be calculated by a neural network and based on channel conditions. Additionally or alternatively, the constellation (e.g., component constellation) associated with the second data set transmitted to the second UE can depend on the values of the data in the first data set transmitted to the first UE. That is, the base station can adjust the constellation of the data for the second UE based on the values of the data for the first UE to achieve constructive interference between the transmissions from the first port and the second port when the transmissions from the first port and the second port are received by the second UE, which can improve the reliability of data reception for the data transmitted to the second UE.

[0007] A method is described. The method may include: associating a first port with a set of multiple antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase; associating a second port with the set of multiple antenna elements of the antenna array, the second port being based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; applying the first linear precoding vector to a first input that includes a first combination of a first data set for a first UE and a second data set for a second UE; applying the second linear precoding vector to a second input that includes a second combination of the first data set for the first UE and the second data set for the second UE; and transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0008] A device is described. The device may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the device to: associate a first port with a set of multiple antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase; associate a second port with the set of multiple antenna elements of the antenna array, the second port being based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; apply the first linear precoding vector to a first input that includes a first combination of a first data set for a first UE and a second data set for a second UE; apply the second linear precoding vector to a second input that includes a second combination of the first data set for the first UE and the second data set for the second UE; and transmit the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0009] Another apparatus is described. The apparatus can include: means for associating a first port with a set of a plurality of antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase; means for associating a second port with the set of a plurality of antenna elements of the antenna array, the second port being based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; means for applying the first linear precoding vector to a first input, the first input including a first combination of a first data set for a first UE and a second data set for a second UE; means for applying the second linear precoding vector to a second input, the second input including a second combination of the first data set for the first UE and the second data set for the second UE; and means for transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0010] A non-transitory computer-readable medium storing code is described. The code can include instructions executable by a processor to: associate a first port with a set of a plurality of antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase; associate a second port with the set of a plurality of antenna elements of the antenna array, the second port being based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; apply the first linear precoding vector to a first input, the first input including a first combination of a first data set for a first UE and a second data set for a second UE; apply the second linear precoding vector to a second input, the second input including a second combination of the first data set for the first UE and the second data set for the second UE; and transmit the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0011] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, based on the second phase of the second port being coherent with the first phase of the first port, the first transmission beam and the second transmission beam interfere constructively.

[0012] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein can further include operations, features, means, or instructions for adjusting the constellation of the second data set based on the first data set.

[0013] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the adjustment can include operations, features, means, or instructions for adjusting the constellation of each symbol of the second data set based on a corresponding value indicated by each respective symbol of the first data set.

[0014] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the first constellation of the first data set includes a first quadrature phase shift keying (QPSK) constellation, and the constellation of the second data set can be a second constellation and includes a second QPSK constellation, wherein adjusting the second constellation of the second data set includes marking the second QPSK constellation based on the first data set.

[0015] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: generating a first set of coefficients indicative of the first combination of the first data set and the second data set based on one or more channel metrics, wherein applying the first linear precoding vector may be based on generating the first set of coefficients, and generating a second set of coefficients indicative of the second combination of the first data set and the second data set based on the one or more channel metrics, wherein applying the second linear precoding vector may be based on generating the second set of coefficients.

[0016] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, generating the first set of coefficients and generating the second set of coefficients may be based on the application of a neural network, the input of which includes one or more channel metrics.

[0017] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the one or more channel metrics include an estimate of a downlink precoding channel, a downlink SNR, an expected noise covariance at the downlink precoding channel, or a combination thereof.

[0018] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, transmission may include operations, features, components, or instructions for: transmitting on a first portion of a precoding channel generated by applying the first linear precoding vector to a propagation channel using the first transmission beam corresponding to the first port, and transmitting on a second portion of the precoding channel generated by applying the second linear precoding vector to the propagation channel using a second transmission beam corresponding to the second port.

[0019] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the precoding channel may be based on a two-by-two spatial causal channel of the second port having a second phase that can be coherent with the first phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Examples of wireless communication systems that illustrate support for non-linear precoding for multi-user (MU) multiple-input multiple-output (MIMO) communication in accordance with aspects of the present disclosure are shown.

[0021] Figure 2 Illustrates an example of a precoding scheme that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure.

[0022] Figure 3 Illustrates an example of a component constellation that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure.

[0023] Figure 4 Illustrates an example of a received constellation that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure.

[0024] Figure 5 Illustrates an example of a process flow that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure.

[0025] Figure 6 and Figure 7 Shows a block diagram of a device that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure.

[0026] Figure 8 Shows a block diagram of a communication manager that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure.

[0027] Figure 9 Shows a diagram of a system that includes a device that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure.

[0028] Figures 10 to 13 Shows a flowchart that illustrates a method that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure. Detailed Description

[0029] In some wireless communication systems (e.g., multiple-input multiple-output (MIMO) systems, multi-user (MU) MIMO (MU-MIMO) systems), a base station may use non-linear precoding, such as Tomlinson-Harashima precoding (THP). In some examples of non-linear precoding, the base station may create two ports for a shared channel transmission that may include data for two user equipment (UEs). The base station may transmit data to a first UE using a first port and may apply non-linear precoding (e.g., THP) before transmitting data to a second UE using a second port. By applying non-linear precoding to the data before transmitting it to the second UE, the base station may reduce the amount of interference between the transmission to the first UE via the first port and the transmission to the second UE via the second port. However, in the case where the shared channel is associated with a relatively low signal-to-noise ratio (SNR), applying THP before transmitting data via the second port may effectively result in destructive interference to the transmission to the first UE via the first port, thereby reducing the power of the transmission to the first UE via the first port and increasing the interference between the transmissions. Additionally, any un-cancelled interference (or interference not cancelled by the destructive summation of the transmissions) may still remain as noise in the transmission to the second UE via the second port.

[0030] The techniques described herein enable a base station to utilize an enhanced precoding scheme for shared channel data transmission to two UEs. In some cases, the described techniques may increase the received signal power for the transmission to the second UE, as the base station may transmit data to the first UE in low SNR conditions. The base station may associate a first port for shared channel transmission with a set of antenna elements of an antenna array and may associate a second port for shared channel transmission with the set of antenna elements of the antenna array. The first port may have a first phase and may be based on a first linear precoding vector, and the second port may be based on a second linear precoding vector and a phase shift such that the second port may have a second phase coherent with the first phase. That is, the base station may apply linear precoding to generate transmissions with constructive interference via the first port and the second port.

[0031] In some examples, a base station may use a first port and a second port to transmit data associated with both a first UE and a second UE. For example, the base station may use the first port to transmit a linear combination of a first data set for the first UE and a second data set for the second UE to the first UE, and the base station may use the second port to transmit a different linear combination of the first data set and the second data set to the second UE. In some examples, the linear combination of the first data set and the second data set may be calculated by a neural network and based on channel conditions. Additionally or alternatively, a constellation (e.g., a component constellation) associated with the second data set transmitted to the second UE may depend on values of data in the first data set transmitted to the first UE. That is, the base station may adjust the constellation of the data for the second UE based on the values of the data for the first UE to achieve constructive interference between transmissions from the first port and the second port when the transmissions from the first port and the second port are received by the second UE, which may improve the reliability of data reception for the data transmitted to the second UE.

[0032] Aspects of the present disclosure are first described in the context of a wireless communication system. Aspects of the present disclosure are then described in the context of a precoding scheme, component constellations, and process flows. Aspects of the present disclosure are also illustrated and described by and with reference to apparatus diagrams, system diagrams, and flowcharts associated with non-linear precoding for MU-MIMO communication.

[0033] Figure 1 An example of a wireless communication system 100 that supports non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure is illustrated. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communication, ultra-reliable communication, low-latency communication, or communication with low-cost and low-complexity devices, or any combination thereof.

[0034] The base stations 105 may be dispersed over a geographic area to form the wireless communication system 100, and may be devices of different forms or having different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base stations 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support signal communication in accordance with one or more radio access technologies.

[0035] UE 115 can be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 can be stationary or mobile, or stationary and mobile at different times. UE 115 can be a device in different forms or with different capabilities. Figure 1 Some example UEs 115 are illustrated in Figure 1 As shown, the UE 115 described herein can be capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment).

[0036] Base stations 105 can communicate with the core network 130, or with each other, or both. For example, base stations 105 can interface with the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). Base stations 105 can communicate with each other directly (e.g., directly between base stations 105) or indirectly (e.g., via the core network 130) or both via backhaul links 120 (e.g., via X2, Xn, or other interfaces). In some examples, the backhaul link 120 can be or include one or more wireless links.

[0037] One or more of the base stations 105 described herein can include or can be referred to by those of ordinary skill in the art as transceiver base stations, radio base stations, access points, radio transceivers, NodeB, eNodeB (eNB), next-generation NodeB, or giga NodeB (any of which can be referred to as gNB), home NodeB, home eNodeB, or other suitable terms.

[0038] UE 115 can include or can be referred to as a mobile device, wireless device, remote device, handheld device, or subscriber device, or some other suitable term, where "device" can also be referred to as a unit, station, terminal, or client, etc. UE 115 can also include or can be referred to as a personal electronic device, such as a cellular phone, personal digital assistant (PDA), tablet computer, laptop computer, or personal computer. In some examples, UE 115 can include or can be referred to as a wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, or machine type communication (MTC) device, etc., which can be implemented in various objects such as appliances, vehicles, meters, etc.

[0039] As Figure 1As shown, the UE 115 described herein may be capable of communicating with various types of devices, such as other UEs 115 that may sometimes act as relays, as well as base stations 105 and network equipment, including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, etc.

[0040] The UE 115 and the base station 105 may wirelessly communicate with each other via one or more communication links 125 on one or more carriers. The term "carrier" may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, a carrier for the communication link 125 may include a portion (e.g., a bandwidth part (BWP)) of a radio frequency spectrum band operating according to one or more physical layer channels of a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operation, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. According to a carrier aggregation configuration, the UE 115 may be configured to have multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used for both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0041] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling for coordinating the operation of other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)) and may be located according to a channel raster for discovery by the UE 115. A carrier may operate in an independent mode, in which initial acquisition and connection may be made by the UE 115 via the carrier, or a carrier may operate in a non-independent mode, in which a connection is anchored using different carriers (e.g., of the same or different radio access technologies).

[0042] The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. A carrier may carry downlink communication or uplink communication (e.g., in FDD mode), or may be configured to carry both downlink communication and uplink communication (e.g., in TDD mode).

[0043] A carrier can be associated with a specific bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth can refer to the "system bandwidth" of the carrier or the wireless communication system 100. For example, the carrier bandwidth can be one of multiple determined bandwidths of a carrier for a specific radio access technology (e.g., 1.4 megahertz (MHz), 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, 40 MHz, or 80 MHz). Devices of the wireless communication system 100 (e.g., the base station 105, the UE 115, or both) can have a hardware configuration that supports communication on a specific carrier bandwidth or can be configurable to support communication on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 can include a base station 105 or a UE 115 that supports simultaneous communication via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 can be configured to operate on a portion (e.g., a subband, a BWP) or all of the carrier bandwidth.

[0044] The signal waveform transmitted on a carrier can include multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system that employs MCM techniques, a resource element can include one symbol period (e.g., the duration of one modulated symbol) and one subcarrier, where the symbol period and the subcarrier spacing are inversely related. The number of bits carried by each resource element can depend on the modulation scheme (e.g., the order of the modulation scheme, the decoding rate of the modulation scheme, or both). Thus, the more resource elements the UE 115 receives and the higher the order of the modulation scheme, the higher the data rate can be for the UE 115. Wireless communication resources can refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers can also increase the data rate or data integrity for communicating with the UE 115.

[0045] The time intervals of the base station 105 or the UE 115 can be expressed as multiples of a basic time unit, which can refer to, for example, the sampling period T s = 1 / (Δf max ·N f ) seconds, where Δf max can represent the maximum supported subcarrier spacing, and N f can represent the maximum supported discrete Fourier transform (DFT) size. The time intervals of the communication resources can be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame can be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0046] Each frame may include a plurality of consecutively numbered sub - frames or time slots, and each sub - frame or time slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into sub - frames, and each sub - frame may also be divided into a number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the sub - carrier spacing. Each time slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, a time slot may also be divided into multiple mini - time slots each containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N f f

[0047] sub - frames, time slots, mini - time slots, or symbols may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in the TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of short TTIs (sTTIs)).

[0048] Physical channels may be multiplexed on a carrier according to various techniques. For example, one or more of time - division multiplexing (TDM) techniques, frequency - division multiplexing (FDM) techniques, or hybrid TDM - FDM techniques may be used to multiplex physical control channels and physical data channels on a downlink carrier. The control region of a physical control channel (e.g., a control resource set (CORESET)) may be defined by a number of symbol periods and may extend across the system bandwidth of the carrier or a subset of the system bandwidth. One or more control regions (e.g., CORESETs) may be configured for a group of UEs 115. For example, one or more of the UEs 115 may monitor or search a control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level of a control channel candidate may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with the coded information for a control information format with a given payload size. The search space set may include: a common search space set configured to send control information to multiple UEs 115, and a UE - specific search space set for sending control information to a specific UE 115.

[0049] Each base station 105 can provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" can refer to a logical communication entity used for communication with a base station 105 (e.g., on a carrier), and can be associated with an identifier (e.g., physical cell identifier (PCID), virtual cell identifier (VCID), or others) for differentiating adjacent cells. In some examples, a cell can also refer to a geographical coverage area 110 or a portion of the geographical coverage area 110 (e.g., a sector) on which the logical communication entity operates. Depending on various factors such as the capabilities of the base station 105, the range of the cell can vary from a relatively small area (e.g., a structure, a subset of a structure) to a relatively large area. For example, a cell can be or can include a building, a subset of a building, or an external space between or overlapping with the geographical coverage area 110, and so on.

[0050] Macro cells generally cover a relatively large geographical area (e.g., with a radius of several kilometers) and can allow UEs 115 with a service subscription to the network provider supporting the macro cell to access without restriction. Compared with macro cells, small cells can be associated with base stations 105 with lower power, and small cells can operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells can provide unrestricted access to UEs 115 with a service subscription to the network provider, or can provide restricted access to UEs 115 associated with the small cell (e.g., UEs 115 in a closed user group (CSG), UEs 115 associated with users in a home or office). A base station 105 can support one or more cells and can also use one or more component carriers to support communication on one or more cells.

[0051] In some examples, the base station 105 can be movable and thus provide communication coverage for a moving geographical coverage area 110. In some examples, different geographical coverage areas 110 associated with different technologies can overlap, but different geographical coverage areas 110 can be supported by the same base station 105. In other examples, overlapping geographical coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 can include, for example, a heterogeneous network in which different types of base stations 105 provide coverage for various geographical coverage areas 110 using the same or different radio access technologies.

[0052] Some UEs 115 (such as MTC or IoT devices) can be low-cost or low-complexity devices and can provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC can refer to data communication technologies that allow devices to communicate with each other or with the base station 105 without human intervention. In some examples, M2M communication or MTC can include communication from devices integrated with sensors or meters to measure or capture information and relay such information to a central server or application that utilizes the information or presents the information to a person interacting with the application. Some UEs 115 can be designed to collect information or implement automated behavior of machines or other devices. Examples of applications for MTC devices include: smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wilderness survival monitoring, weather and geographical event monitoring, formation management and tracking, remote security sensing, physical access control, and transaction-based commercial charging.

[0053] Some UEs 115 can be configured to operate in power-saving modes, such as half-duplex communication (e.g., a mode that supports one-way communication via transmission or reception but does not support simultaneous transmission and reception). In some examples, half-duplex communication can be performed at a reduced peak rate. Other energy-saving techniques for UEs 115 include: entering an energy-saving deep sleep mode when not participating in active communication, operating on limited bandwidth (e.g., according to narrowband communication), or a combination of these techniques. For example, some UEs 115 can be configured to operate using a narrowband protocol type associated with a defined portion or range (e.g., a set of subcarriers or resource blocks (RBs)) within a carrier, within a guard band of the carrier, or outside the carrier.

[0054] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC). UEs 115 can be designed to support ultra-reliable or low-latency or critical functions. Ultra-reliable communication can include private communication or group communication and can be supported by one or more services (such as push-to-talk, video, or data). Support for ultra-reliable, low-latency functions can include prioritization of services, and such services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency can be used interchangeably herein.

[0055] In some examples, UE 115 may also be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (e.g., using peer-to-peer (P2P) or D2D protocols). One or more UEs 115 utilizing D2D communication may be located within the geographic coverage area 110 of base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of base station 105 or may be unable to receive transmissions from base station 105 for other reasons. In some examples, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system where each UE 115 transmits to every other UE 115 in the group. In some examples, base station 105 facilitates scheduling of resources for D2D communication. In other cases, D2D communication is performed between these UEs 115 without the participation of base station 105.

[0056] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for UEs 115 served by base station 105 associated with the core network 130. User IP packets may be transmitted through the user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to IP services 150 for one or more network operators. The IP services 150 may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or packet-switched streaming services.

[0057] Some network devices (such as base station 105) may include sub-components, such as access network entity 140, which can be an example of an access node controller (ANC). Each access network entity 140 can communicate with UE 115 through one or more other access network transmission entities 145, which can be referred to as radio heads, intelligent radio heads, or transmission / reception points (TRPs). Each access network transmission entity 145 can include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 can be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., base station 105).

[0058] Wireless communication system 100 can operate using one or more frequency bands, for example, in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or the decimeter band because the wavelength range is approximately one decimeter to one meter. UHF waves may be blocked or redirected by buildings and environmental features, but these waves can be sufficient to penetrate structures so that macrocells can serve UEs 115 located indoors. Compared with transmissions at smaller frequencies and longer wavelengths using the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz, UHF wave transmissions can be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers).

[0059] Wireless communication system 100 can also operate in the super-high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz (also referred to as the centimeter band) or in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) (also referred to as the millimeter band). In some examples, wireless communication system 100 can support millimeter wave (mmW) communication between UE 115 and base station 105, and the EHF antennas of the corresponding devices can be smaller and closer spaced than UHF antennas. In some examples, this can help with the use of antenna arrays within the device. However, the propagation of EHF transmissions may be affected by greater atmospheric attenuation and shorter ranges than SHF or UHF transmissions. The techniques disclosed herein can be employed across transmissions using one or more different frequency regions, and the use of frequency bands specified across these frequency regions can vary by country or regulatory body.

[0060] The wireless communication system 100 can utilize both licensed and unlicensed radio frequency bands. For example, the wireless communication system 100 can use licensed-assisted access (LAA), LTE-unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in an unlicensed radio frequency band, devices (such as base station 105 and UE 115) can employ carrier sensing for collision detection and collision avoidance. In some examples, operation in an unlicensed band can be based on a carrier aggregation configuration (e.g., LAA) in combination with a component carrier operating in a licensed band. Operations in the unlicensed spectrum can include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, etc.

[0061] Base station 105 or UE 115 can be equipped with multiple antennas, which can be used to employ techniques such as transmit diversity, receive diversity, MIMO, or beamforming. The antennas of base station 105 or UE 115 can be located within one or more antenna arrays or antenna panels, which can support MIMO operation or transmit beamforming or receive beamforming. For example, one or more base station antennas or antenna arrays can be co-located at an antenna assembly, such as an antenna tower. In some examples, the antennas or antenna arrays associated with base station 105 can be located at different geographical locations. Base station 105 can have an antenna array with multiple rows and columns of antenna ports, and base station 105 can use these antenna ports to support beamforming for communication with UE 115. Similarly, UE 115 can have one or more antenna arrays, which can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel can support radio frequency beamforming for signals transmitted via the antenna ports.

[0062] Base station 105 or UE 115 can use MIMO communication to utilize multipath signal propagation and improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques can be referred to as spatial multiplexing. For example, multiple signals can be transmitted by a transmitting device via different antennas or different combinations of antennas. Similarly, multiple signals can be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals can be referred to as a separate spatial stream and can carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers can be associated with different antenna ports for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) and multi-user MIMO (MU-MIMO), where in SU-MIMO, multiple spatial layers are transmitted to the same receiving device, and in MU-MIMO, multiple spatial layers are transmitted to multiple devices.

[0063] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., base station 105, UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals transmitted via the antenna elements of an antenna array such that some signals propagating in a particular direction relative to the antenna array experience constructive interference while other signals experience destructive interference. The adjustment of the signals transmitted via the antenna elements can include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to the signals carried via the antenna elements associated with the device. The adjustment associated with each of these antenna elements can be defined by a set of beamforming weights associated with a particular direction (e.g., relative to the antenna array of the transmitting device or receiving device or relative to some other direction).

[0064] The base station 105 or the UE 115 can use beam scanning techniques as part of the beamforming operation. For example, the base station 105 can use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) can be transmitted by the base station 105 multiple times in different directions. For example, the base station 105 can transmit signals according to different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions can be used to identify (e.g., by the transmitting device such as the base station 105, or by the receiving device such as the UE 115)) the beam direction for later transmission or reception by the base station 105.

[0065] Some signals (such as data signals associated with a particular receiving device) can be transmitted by the base station 105 in a single beam direction (e.g., the direction associated with the receiving device such as the UE 115). In some examples, the beam direction associated with the transmission along a single beam direction can be determined based on signals transmitted in one or more beam directions. For example, the UE 115 can receive one or more of the signals transmitted by the base station 105 in different directions and can report to the base station 105 an indication of the signal that the UE 115 receives with the highest signal quality or other acceptable signal quality.

[0066] In some examples, transmissions made by a device (e.g., by base station 105 or UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from base station 105 to UE 115). UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. Base station 105 may transmit reference signals (e.g., cell-specific reference signal (CRS), channel state information reference signal (CSI-RS)), which may or may not be precoded. UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., polyhedron codebook, linear combination codebook, port selection codebook). Although these techniques are described with reference to signals transmitted by base station 105 in one or more directions, UE 115 may employ similar techniques to transmit signals multiple times in different directions (e.g., for identifying beam directions for subsequent transmission or reception by UE 115), or to transmit signals in a single direction (e.g., for transmitting data to a receiving device).

[0067] A receiving device (e.g., UE 115) may attempt multiple receive configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from base station 105. For example, the receiving device may attempt multiple receive directions by: receiving via different antenna subarrays, processing the received signals according to different antenna subarrays, receiving according to different sets of receive beamforming weights (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or processing the received signals according to different sets of receive beamforming weights applied to signals received at multiple antenna elements of an antenna array, where any of these may be referred to as "listening" according to different receive configurations or receive directions. In some examples, the receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration may be aligned with a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest SNR, or other acceptable signal quality based on listening according to multiple beam directions).

[0068] The wireless communication system 100 can be a packet-based network that operates according to a hierarchical protocol stack. In the user plane, the communication at the bearer or Packet Data Convergence Protocol (PDCP) layer can be IP-based. The Radio Link Control (RLC) layer can perform packet segmentation and reassembly for communication over logical channels. The Medium Access Control (MAC) layer can perform priority handling and multiplexing of logical channels into transport channels. The MAC layer can also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer can provide the establishment, configuration, and maintenance of an RRC connection that supports the radio bearers for user plane data between the UE 115 and the base station 105 or the core network 130. At the physical layer, the transport channels can be mapped to physical channels.

[0069] In some wireless communication systems 100 (e.g., MIMO systems, MU-MIMO systems), due to the small spatial separation between channels, one or more channels of one or more UEs 115 may be highly correlated. For example, two UEs 115 can be positioned close to each other, which may increase the interference between the corresponding channels of the UEs 115 for MU-MIMO transmission. To reduce the impact of high correlation, the base station 105 can apply a non-linear precoding technique such as THP to the MU-MIMO transmission.

[0070] In some examples, using THP, base station 105 can create two ports (e.g., beams) for shared channel transmission (e.g., Physical Downlink Shared Channel (PDSCH) transmission), and the shared channel transmission can include data for two UEs 115 each having one layer. For example, base station 105 can apply linear precoding, which can convert the MU-MIMO channel (e.g., propagation channel) into a two-by-two spatial causal precoding channel, thus effectively creating two ports (e.g., Demodulation Reference Signal (DMRS) ports) for shared channel transmission. In some examples, base station 105 can use the first port to transmit modulated symbols intended for the first UE 115, and base station 105 can use the second port to transmit symbols precoded by THP to the second UE 115. That is, base station 105 can use the first port to transmit data to the first UE 115 and can apply THP before using the second port to transmit data to the second UE 115. Since the precoding channel is spatial causal, the first UE 115 can receive a small to zero amount of data transmitted from the second port that is intended for the second UE 115, while the second UE 115 can receive both data transmitted from the first port that is intended for the first UE 115 and data transmitted from the second port that is intended for the second UE 115. However, base station 105 can apply interference precancellation in the form of THP precoded symbols to the second UE 115, such that the second UE 115 can receive a reduced amount of interference from the data intended for the first UE 115.

[0071] The precoding channel (e.g., HP) can be based on applying some linear precoding to the propagation channel (e.g., H). In some examples, the product of the propagation channel H and the linear precoding can result in a precoding channel matrix where H can represent a 2×Nt channel, where Nt can represent the number of physical antennas in the antenna array, where l i,i >0 and P can represent some linear precoding matrix, e.g., P = [p1 p2]. In some cases, p1 and p2 can be calculated by the LQ decomposition of [H βI] (e.g., decomposing the matrix into the product of a lower triangular matrix (L) and a unitary matrix (Q)), where β can represent a regularization factor, and I is the identity matrix. In HP, the first column can correspond to transmission via the first port, and the second column can correspond to transmission via the second port. Additionally, the first row in HP can correspond to the channel seen by the first UE 115, and the second row can correspond to the channel seen by the second UE 115. That is, the first UE 115 may see data transmitted from the first port (e.g., l 1,1, the channel coefficient of the data transmitted from the first port) and may fail to see the data transmitted from the second port, while the second UE 115 may see the data transmitted from the first port (e.g., l 2,1 , the channel coefficient of the data transmitted from the first port) and the data transmitted from the second port (e.g., l 2,2 , the channel coefficient of the data transmitted from the second port).

[0072] In some examples, the base station 105 may apply interference precancellation in the form of THP to the second port. For example, the base station 105 may apply the input value u2 - αu1 where u1 and u2 may represent regular quadrature amplitude modulation (QAM) constellations (e.g., quadrature phase shift keying (QPSK), 16QAM), and α may represent a precancellation factor calculated from an assumed channel for the interference signal from the first port received by the second UE 115 (e.g., l 2,1 ) and the SNR associated with the assumed channel of the second UE (e.g., or noise covariance matrix). In some examples, u2 may include modulation symbols carrying a message for the second UE 115. Thus, the input value u2 - αu1 can indicate interference precancellation by canceling a portion of u1 from u2 before applying u2 to the second port and linear precoding. In some cases, u1 may include modulation symbols for the first UE 115. In some examples, the base station 105 may apply a modulo operation (e.g., Mod) to the I and Q phases of the input value u2 - αu1, which may result in the input to the second port. In some cases with limited SNR, partial precancellation may be used, and in cases with low SNR, the base station 105 may select α such that the base station 105 can refrain from applying the modulo operation to the input value.

[0073] In some examples, the first port may have an input value u1, which may be a direct input value to the first port (e.g., DMRS port 1, for the propagation channel of the first UE 115). The base station 105 may apply a linear precoding matrix P = [p1 p2] to form the first port and the second port (e.g., DMRS port 2, for the propagation channel of the second UE 115), and the base station 105 may use the first port to transmit modulated symbols to the first UE 115 and use the second port to transmit THP precoded symbols to the second UE 115. THP precoding may introduce shaping loss (e.g., 1.53 dB) in high SNR scenarios, modulus loss in low SNR scenarios, and power loss in low-order modulation (e.g., QPSK). That is, for cases with high SNR, the main source of loss of THP precoding may be shaping loss, while for cases with low SNR, the main sources of loss of THP precoding may be power loss and modulus loss in addition to shaping loss. In some examples, the loss may be mitigated by scaling α at the base station 105 (e.g., by using partial interference precancellation), by deactivating the modulus operation at the UE 115, by using maximum likelihood decoding, or any combination thereof. However, any interference that the base station 105 fails to cancel may still remain as noise for the UE 115 (e.g., the second UE 115) applying THP. Therefore, in cases with low SNR, applying THP before transmitting data via the second port may lack performance benefits over optimized linear precoding such as regularized zero-forcing precoding.

[0074] In some cases, the base station 105 may use an enhanced precoding scheme to perform shared channel data transmission to two UEs 115. In some cases, the described techniques may increase the received signal power for transmission to the second UE 115, since the base station 105 may transmit data to the first UE 115 in low SNR conditions. The base station 105 may associate the first port for shared channel transmission with a set of antenna elements of the antenna array, and associate the second port for shared channel transmission with the set of antenna elements of the antenna array. The first port may have a first phase and may be based on a first linear precoding vector, and the second port may be based on a second linear precoding vector and a phase shift such that the second port may have a second phase coherent with the first phase. That is, the base station 105 may apply linear precoding to generate a transmission with constructive interference via the first port and the second port.

[0075] In some examples, the base station 105 may use a first port and a second port to transmit data associated with both the first UE 115 and the second UE 115. For example, the base station 105 may use the first port to transmit a linear combination of a first data set for the first UE 115 and a second data set for the second UE 115 to the first UE 115 and the second UE 115, and the base station 105 may use the second port to transmit a different linear combination of the first data set and the second data set to the second UE 115. In some examples, the linear combination of the first data set and the second data set may be calculated by a neural network and based on the channel conditions. Additionally or alternatively, the constellation (e.g., component constellation) associated with the second data set transmitted to the second UE 115 may depend on the values of the data in the first data set transmitted to the first UE 115. That is, the base station 105 may adjust the constellation of the data for the second UE 115 based on the values of the data for the first UE 115 to achieve constructive interference between the transmissions from the first port and the second port when the transmissions from the first port and the second port are received by the second UE 115, which may improve the reliability of data reception for the data transmitted to the second UE 115.

[0076] Figure 2 An example of a precoding scheme 200 that illustrates support for non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure is shown. In some examples, the precoding scheme 200 may implement aspects of the wireless communication system 100, or may be implemented by aspects of the wireless communication system 100. The precoding scheme 200 may include a component constellation u1 and a component constellation u2, which may correspond to data that the base station 105-a may transmit to the UE 115-a and the UE 115-b, respectively. Additionally or alternatively, the precoding scheme 200 may include a linear transformation matrix 205 and a linear precoding matrix 210.

[0077] The pre-coding scheme 200 may support enhanced pre-coding for shared channel data transmission to the UE 115. In some examples, the base station 105-a may associate port 1 (e.g., the first port) with a set of antenna elements of the antenna array, where port 1 may have a first phase based on a first linear pre-coding vector. Port 1 may be associated with the propagation channel, and the base station 105-a may apply the first linear pre-coding vector to the propagation channel such that the propagation channel becomes a pre-coded channel. Additionally or alternatively, port 1 may be associated with the component constellation u1 for transmitting data to the UE 115-a. In some examples, the base station 105-a may associate port 2 (e.g., the second port) with the set of antenna elements of the antenna array, where port 2 may be based on a second linear pre-coding vector. Port 2 may be associated with the propagation channel, and the base station 105-a may apply the second linear pre-coding vector to the propagation channel such that the propagation channel becomes a pre-coded channel (e.g., HP). Additionally or alternatively, port 2 may be associated with the component constellation u2 for transmitting data to the UE 115-b. In some cases, port 2 may have a phase shift such that port 2 has a second phase that is coherent (e.g., constructive interference) with the first phase. Thus, the pre-coded channel may be a two-by-two spatial causal channel based on port 2 having a second phase that is coherent with the first phase.

[0078] In some cases, the base station 105-a may use the component constellation u1 and the component constellation u2 to transmit messages to the UE 115-a and the UE 115-b respectively, where u1 may be from a conventional QPSK constellation and u2 may be from a QPSK constellation that depends on u1. In some examples, the component constellation u1 may be associated with a first data set for the UE 115-a, and the component constellation u2 may be associated with a second data set for the UE 115-b. As referred to Figure 3 above, the base station 105-a may transmit different constellation points of the constellation component u1 to the UE 115-a, and the base station 105-a may transmit different constellation points of the component constellation u2 to the UE 115-b based on the constellation points transmitted to the UE 115-a.

[0079] In some examples, the base station 105-a may generate a first set of coefficients indicating a first combination of the first data set and the second data set, and a second set of coefficients indicating a second combination of the first data set and the second data set, based on one or more channel metrics. For example, the base station 105-a may apply a linear transformation matrix 205 to the component constellation u1 and the component constellation u2. The linear transformation matrix 205 may be given as where α i,j >0 may represent a linear combination coefficient for the first data set for the UE 115-a and the second data set for the UE 115-b, and where αi,j It can be determined according to the propagation channel H (for example, the assumed downlink channel) and the SNR corresponding to the propagation channel H, or determined by a neural network. Applying the linear transformation matrix 205 can result in a linear combination of the contributions (e.g., data) from the component constellations u1 and u2 corresponding to ports 1 and 2. For example, the output of the linear transformation matrix 205 for port 1 can be α 11 u1 + α 12 u2, and for port 2 can be α 22 u2 + α 21 u1, where each coefficient in the linear combination can be a positive real number. For example, the linear combination α 11 u1 + α 12 u2 corresponding to port 1 can include a first data set for UE 115-a (e.g., α 11 u1) and a first combination of a second data set for UE 115-b (e.g., α 12 u2), and the linear combination α 22 u2 + α 21 u1 corresponding to port 2 can include a first data set for UE 115-a (e.g., α 21 u1) and a second combination of a second data set for UE 115-b (e.g., α 22 u2).

[0080] In some cases, base station 105-a can use a neural network to calculate the linear combination coefficient α i,j , where the input to the neural network can include one or more channel metrics. For example, the channel state information (CSIT) at the transmitter (e.g., at base station 105) can be input into the neural network (e.g., a multi-layer perceptron (MLP)) to calculate α i,j , which is used to calculate the inputs for ports 1 and 2 (e.g., the linear combination of the contributions from component constellations u1 and u2). Additionally or alternatively, CSIT can be used for training data generation, and the generated training data can be input into a backpropagation-based solver to calculate α i,j . In some examples, the channel metrics (e.g., CSIT) can include an estimate of the precoded channel HP, the downlink SNR, the expected noise covariance at the downlink precoded channel, or any combination thereof.

[0081] In some cases, base station 105-a can apply the linear precoding matrix 210 to the linear combination of the contributions from component constellations u1 and u2. For example, base station 105-a can apply (e.g., α corresponding to port 1 11 u1 + α 12u2) The first linear precoding vector of the linear precoding matrix 210 is applied to the first input (e.g., p1), and (e.g., α corresponding to port 2) 22 u2 + α 21 u1) The second linear precoding vector of the linear precoding matrix 210 is applied to the second input (e.g., ). In other words, p1(α 11 u1 + α 12 u2) and can be input into the same set of antenna elements. The linear precoding matrix 210 can be given as where p1 and p2 can be calculated according to the LQ decomposition of the downlink channel H such that H is a spatially causal channel, where l i,i > 0 (e.g., l 1,1 and l 2,2 are positive real values). In some examples, can represent a phase rotation for matching the phase of the contribution from port 2 with the phase of the interference channel (e.g., for the channel coefficient of port 1, l 2,1 ), such that the contributions from the two ports add coherently (e.g., constructive interference) at UE 115 - b. The first phase of the first port can be given by the phase of l 2,1 , and the second phase of the second port can be given by the phase of . For example, base station 105 - a can apply linear precoding in the form of p1 to port 1, and apply linear precoding in the form of to port 2, which can convert the propagation channel H (e.g., the downlink MU - MIMO channel) into a two - by - two spatially causal channel, thus effectively creating two ports for PDSCH transmission.

[0082] In some examples, base station 105 - a can transmit the first combination and the second combination of the first data set and the second data set (e.g., the first input and the second input) to both UE 115 - a and UE 115 - b after applying the linear precoding matrix 210. For example, base station 105 - a can use the first transmission beam corresponding to port 1 to transmit the first input (e.g., α 11 u1 + α 12 u2) to UE 115 - a and UE 115 - b, and use the second transmission beam corresponding to port 2 to transmit the second input (e.g., α 21 u1 + α 22u2). Additionally or alternatively, base station 105-a may transmit on a first portion of a precoded channel (e.g., HP) generated by applying a first linear precoding vector (e.g., p1) to a propagation channel (e.g., H) using a first transmission beam corresponding to port 1. The first portion of the precoded channel may correspond to the first column of HP given by the vector Transmissions from port 1 may reach both UE 115-a and UE 115-b. Base station 105-a may transmit on a second portion of a precoded channel (e.g., HP) generated by applying a second linear precoding vector (e.g., ) to the propagation channel (e.g., H) using a second transmission beam corresponding to port 2. The second portion of the precoded channel may correspond to the second column of HP given by the vector Transmissions from port 2 may reach UE115-b. In some examples, the precoded channel HP may be a two-by-two spatial causal channel with a second phase (e.g., the phase of channel coefficient 2,1 ) that is coherent with a first phase (e.g., the phase of channel coefficient ) based on port 2.

[0083] Figure 3 Illustrates an example of a component constellation 300 that supports non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure. In some examples, component constellation 300 may implement aspects of wireless communication system 100 or may be implemented by aspects of wireless communication system 100.

[0084] As described herein, a base station may use an enhanced precoding scheme to transmit shared channel data to two UEs. In some examples, base station 105-a may use different component constellations u1 and u2 to convey messages to two UEs. For example, the base station may use component constellation 305 (e.g., component constellation u1) to communicate with a first UE, where u1 may be from a conventional QPSK constellation, and the base station may use component constellation 310 (e.g., component constellation u2) to communicate with a second UE, where u2 may be from a QPSK constellation that depends on u1. That is, what the base station transmits to the second UE may depend on what the base station transmits to the first UE. In some examples, component constellation 305 may be associated with a first data set (e.g., including modulation symbols) of a first UE, and component constellation 310 may be associated with a second data set (e.g., including modulation symbols) of a second UE.

[0085] The component constellation 305 may include four constellation points (e.g., 0, 1, 2, 3), and the base station may use each of these constellation points to transmit a message to the first UE. For example, the base station may use constellation point 0 to send message 0 to the first UE, constellation point 1 to send message 1, constellation point 2 to send message 2, and constellation point 3 to send message 3. That is, the base station may send one of the four constellation points to the first UE based on the message that the base station may choose to send. In some cases, the component constellation 305 may be a conventional QPSK constellation, where the base station may transmit one of the four constellation points in the component constellation 305 according to the message intended for the first UE.

[0086] In some cases, the base station may use the component constellation 310 to transmit a message to the second UE, and this component constellation may be based on the constellation points of the component constellation 305 used by the base station to transmit a message to the first UE. For example, the base station may adjust the component constellation 310 based on a first data set (e.g., component constellation u1).

[0087] In some examples, the base station may use the component constellation 310-a (which may represent the component constellation u2 depending on u1 = "1"), the component constellation 310-b (which may represent the component constellation u2 depending on u1 = "0"), the component constellation 310-c (which may represent the component constellation u2 depending on u1 = "2"), and the component constellation 310-d (which may represent the component constellation u2 depending on u1 = "3"). The base station may adjust (e.g., use) each modulation symbol of a second data set (e.g., u2) based on the corresponding value indicated by each respective symbol of the first data set (e.g., u1). For example, if the base station uses constellation point 1 from the component constellation 305 (e.g., u1 = "1") to transmit message 1 to the first UE, the base station may use one of the four constellation points in the component constellation 310-a (which depends on u1 = "1") to transmit a message to the second UE. If the base station uses constellation point 0 from the component constellation 305 (e.g., u1 = "0") to transmit message 0 to the first UE, the base station may use one of the four constellation points in the component constellation 310-b (which depends on u1 = "0") to transmit a message to the second UE, and so on.

[0088] In some examples, the four component constellations 310 can each be a regular QPSK component constellation with different message tags, and the different message tags can correspond to different messages transmitted to the first UE. For example, the base station can use a specific component constellation 310 based on which component constellation 310 corresponds to the message transmitted to the UE. In some examples, in the case where the component constellation 305 (e.g., corresponding to the first data set) includes a QPSK constellation and the component constellation 310 (e.g., corresponding to the second data set) includes a second QPSK constellation, the base station can adjust the component constellation 310 by adjusting the tag of the component constellation 310 based on the first data set.

[0089] In some examples, the input to port 1 can be a linear combination of a first modulation symbol (e.g., a first constellation point) from the component constellation 305 and a second modulation symbol (e.g., a second constellation point depending on the first constellation point) from the component constellation 310 that depends on the first modulation symbol. That is, the input to port 1 can be a combination of a first data set corresponding to the first UE and a second data set corresponding to the second UE. Additionally or alternatively, the input to port 2 can be a different linear combination of a first modulation symbol (e.g., a first constellation point) from the component constellation 305 and a second modulation symbol (e.g., a second constellation point depending on the first constellation point) from the component constellation 310 that depends on the first modulation symbol. That is, the input to port 1 can be a different combination of a first data set corresponding to the first UE and a second data set corresponding to the second UE.

[0090] As referenced Figure 2 As described, the base station can use the component constellation 305 and the component constellation 310 to transmit messages to the first UE and the second UE, respectively. The component constellation 305 (e.g., u1) and the component constellation 310 (e.g., u2) can correspond to the first UE and the second UE, respectively, and can be input into a linear transformation matrix and then a linear precoding matrix before being transmitted to the UE.

[0091] Figure 4 An example of a received constellation 400 that supports non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure is illustrated. The received constellation 400 can include a received constellation 405-a received by a first UE (e.g., UE1) and a received constellation 405-b received by a second UE (e.g., UE2).

[0092] As described herein, the base station can use an enhanced precoding scheme to perform shared channel data transmission to two UEs. For example, the base station can use the component constellation u1 and the component constellation u2 to transmit messages to the first UE and the second UE. The first UE can receive the received constellation 405-a and the second UE can receive the received constellation 405-b.

[0093] In some examples, the channel corresponding to the first UE (e.g., UE1 channel) and the channel corresponding to the second UE (e.g., UE2 channel) can be spatially close to each other such that the angle between the two channels can be small. In some cases, port 1 and port 2 (e.g., corresponding to the channels for transmission to the UE) can be formed by the LQ decomposition of the downlink channel (e.g., H, as referenced Figure 2 and Figure 3 as described). In some examples, port 1 can be directly aligned with the channel for the first UE. However, port 2 can be orthogonal to port 1, and thus, port 2 can be misaligned with the channel for the second UE (e.g., because the channels for the first UE and the second UE are separated by a small angle).

[0094] In some cases, when the channels for the first UE and the second UE are close together and when port 1 and port 2 are orthogonal, in addition to the signal intended for (e.g., transmitted to) the second UE using port 2, the second UE can also see the contribution from the signal intended for (e.g., transmitted to) the first UE using port 1. That is, the signal transmitted to the first UE using port 1 can have a large contribution to the second UE. In some cases, to prevent the second UE from treating the signal intended for the first UE as noise, the base station can use a hierarchical modulation scheme to use the signal intended for the first UE constructively when delivering a message to the second UE using port 2. In some examples, the second UE can receive both the u1 component and the u2 component with high power from port 1 and port 2 to maximize the distance between the hypotheses of each of the two bits (e.g., bit = 0 and bit = 1). For example, each UE can receive two bits. For highly correlated channels corresponding to the first UE and the second UE, port 2 may be less efficient than port 1 in delivering power. Thus, in addition to the component constellation u1, the base station can transmit the component constellation u2 corresponding to the second UE on port 1 to the extent that the overall mutual information delivered to the two UEs is maximized. That is, to maximize the amount of information transmitted to the second UE, the base station can maximize the distance between the hypotheses of each of the two bits, which can be determined by the received power in the component constellation u1 and the component constellation u2.

[0095] The received constellation 405-a for the first UE (e.g., UE1) and the received constellation 405-b for the second UE (e.g., UE2) can each include tags x and tags y (e.g., in Figure 4Multiple received constellation points represented as composite tags x-y). The received constellation points can correspond to messages that the base station can transmit to the first UE and the second UE. For example, the received constellation 405-a can illustrate the composite constellation points that the first UE can receive, and the received constellation 405-b can illustrate the composite constellation points that the second UE can receive. As referenced Figure 3 As described, the tag x can correspond to a message transmitted to the first UE via a given constellation point (e.g., x = {0, 1, 2, 3}), and the tag y can correspond to a message transmitted to the second UE via a given constellation point based on the message transmitted to the first UE (e.g., y = {0, 1, 2, 3}). Since each UE can receive two bits, each UE can receive four possible messages (e.g., 0, 1, 2, 3). For the two received constellations 405-a and received constellation 405-b, the constellation points in the decision region 410 can correspond to message 1, the constellation points in the decision region 415 can correspond to message 0, the constellation points in the decision region 420 can correspond to message 2, and the constellation points in the decision region 425 can correspond to message 3.

[0096] Additionally or alternatively, the markings x-y in the received constellation 405-a and the received constellation 405-b can indicate which messages the first UE and the second UE can receive. For example, the received constellation points with the label 1-3 in the received constellation 405-a and the received constellation 405-b can indicate that the first UE can receive message 1 corresponding to bit 01 and the second UE can receive message 3 corresponding to bit 11 via the indicated constellation points with the marking 1-3. In some cases, the received constellation points with the marking 2-1 in the received constellation 405-a and the received constellation 405-b can indicate that the first UE can receive message 2 and the second UE can receive message 1 via the indicated constellation points with the label 2-1.

[0097] As shown in the received constellation 405-b for the second UE, the base station can transmit message 0 to the second UE, which can correspond to one of the received constellation points with the labels 0-0, 1-0, 2-0, or 3-0 in the decision region 415 based on which constellation point (e.g., 0, 1, 2, or 3) is transmitted to the first UE, or the base station can transmit message 3 to the second UE, which can correspond to one of the received constellation points with the labels 0-3, 1-3, 2-3, or 3-3 in the decision region 425 based on which constellation point (e.g., 0, 1, 2, 3) is transmitted to the first UE.

[0098] In some examples, interference from port 1 (e.g., a message intended for a first UE), e.g., by means of phase alignment, can be added constructively to the content received from port 2 to construct a received constellation 405-b intended for a second UE. That is, the contribution from port 1 as seen by the second UE can be added constructively to the contribution from port 2 as seen by the second UE, rather than being ignored as noise. In this way, the received constellation 405-b can achieve a performance gain at low SNR (e.g., ≤8 dB) and with a high enough channel correlation.

[0099] Figure 5 Illustrates an example of a process flow 500 that supports non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure. The process flow 500 may implement aspects of the wireless communication system 100 or may be implemented by aspects of the wireless communication system 100. For example, the process flow 500 may illustrate communication between the base station 105-b, the UE 115-c, and the UE 115-d, which may be examples of the corresponding devices described herein. In the following description of the process flow 500, operations between the base station 105-b, the UE 115-c, and the UE 115-d may be transmitted in an order different from the illustrated examples, or the operations performed by the base station 105-b, the UE 115-c, and the UE 115-d may be performed in a different order or at different times. Some operations may also be omitted from the process flow 500 and other operations may be added to the process flow 500.

[0100] At 505, the base station 105-b may associate a first port with a set of antenna elements of the antenna array and may associate a second port with the set of antenna elements of the antenna array. In some examples, the first port may be based on a first linear precoding vector and may have a first phase, and the second port may be based on a second linear precoding vector and a phase shift such that the second port may have a second phase that is coherent (e.g., constructive interference) with the first phase. The linear precoding vectors may be calculated based on the LQ decomposition of the propagation channel (e.g., the MU-MIMO channel) to create a precoded channel.

[0101] In some examples, the base station 105-b may use the component constellations of a first data set (e.g., u1) and the component constellations of a second data set (e.g., u2) to transmit data to the UE 115-c and the UE 115-d, respectively. At 510, the base station 105-b may generate a first set of coefficients indicative of a first combination of the first data set and the second data set and a second set of coefficients indicative of a second combination of the first data set and the second data set based on one or more channel metrics. For example, the first set of coefficients and the second set of coefficients (e.g., α ij) In the linear transformation matrix, base station 105-b can apply the first set of coefficients and the second set of coefficients to the component constellations of the first data set and the second data set (e.g., u1 and u2), which can result in a linear combination of the contributions from each component constellation to each UE 115. In some cases, base station 105-b can generate the coefficients by applying a neural network, and the input of the neural network can be one or more channel metrics.

[0102] At 515, base station 105-b can adjust the component constellation of the second data set based on the first data set. For example, base station 105-b can use a specific constellation point of the component constellation from the first data set to transmit a specific message to UE 115-c. Based on using the specific constellation point for the transmission to UE 115-c, base station 105-b can use (e.g., adjust) a specific constellation point of a specific component constellation of the second data set to transmit a specific message to UE 115-d.

[0103] At 520, base station 105-b can apply a first linear precoding vector to a first input, which includes a first combination of the first data set for UE 115-c and the second data set for UE 115-d, and base station 105-b can apply a second linear precoding vector to a second input, which includes a second combination of the first data set and the second data set. The first input and the second input can be linear combinations of the contributions obtained by applying coefficients to the component constellations of the first data set and the second data set. In some examples, base station 105-b can apply linear precoding to the first input and the second input to form a precoded channel (e.g., a two-by-two spatial causal channel) for the transmission to UE 115-c and UE 115-d.

[0104] At 525, base station 105-b can use a first transmission beam corresponding to the first port to transmit a first combination of the first data set for UE 115-c and the second data set for UE 115-d. In some examples, base station 105-b can transmit on a first part of the precoded channel generated by applying the first linear precoding vector to the propagation channel, where the propagation channel can be a two-by-Nt propagation channel matrix (e.g., where Nt can represent the number of physical antennas associated with the channel).

[0105] At 530, UE 115-c can decode the first data set based on the component constellation of the first data set (e.g., u1). For example, UE 115-c can decode a specific message (e.g., message 0, message 1, message 2, message 3) based on the constellation points (e.g., 0, 1, 2, 3) of the component constellation of the first data set that base station 105-b uses to transmit the first combination.

[0106] At 535, base station 105-b may transmit a second combination of a first data set for UE 115-c and a second data set for UE 115-d using a second transmission beam corresponding to the second port. In some examples, base station 105-b may transmit on a second portion of a precoded channel generated by applying a second linear precoding vector to a propagation channel, where the propagation channel may be a two-by-Nt propagation channel matrix.

[0107] At 540, UE 115-d may decode the second data set based on the component constellations of the first data set (e.g., u1) and the second data set (e.g., u2). For example, UE 115-d may decode a particular message (e.g., message 0, message 1, message 2, message 3) based on the constellation points (e.g., 0, 1, 2, 3) of the component constellation of the second data set that base station 105-b uses to transmit the second combination. Additionally or alternatively, UE 115-d may decode a particular message based on the messages and corresponding constellation points that base station 105-b transmits to UE 115-c.

[0108] Figure 6 FIG. 600 is a block diagram illustrating a device 605 that supports non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure. Device 605 may be an example of aspects of base station 105 as described herein. Device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. Device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0109] Receiver 610 may provide components for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to non-linear precoding for MU-MIMO communication). The information may be passed to other components of device 605. Receiver 610 may utilize a single antenna or a set of multiple antennas.

[0110] Transmitter 615 may provide components for transmitting signals generated by other components of device 605. For example, transmitter 615 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to non-linear precoding for MU-MIMO communication). In some examples, transmitter 615 may be co-located with receiver 610 in a transceiver module. Transmitter 615 may utilize a single antenna or a set of multiple antennas.

[0111] The communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof, or various components thereof, can be examples of components for performing aspects of non-linear precoding for MU-MIMO communication as described herein. For example, the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof can support methods for performing one or more functions described herein.

[0112] In some examples, the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof can be implemented in hardware (e.g., in communication management circuitry). The hardware can include a processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof, which are configured to or otherwise support components for performing the functions described in this disclosure. In some examples, a processor and a memory coupled to the processor can be configured to perform one or more functions described herein (e.g., by the processor executing instructions stored in the memory).

[0113] Additionally or alternatively, in some examples, the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof can be implemented in code executed by a processor (e.g., as communication management software or firmware). If implemented in code executed by a processor, the functions of the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof can be performed by a general purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination of these or other programmable logic devices (e.g., configured to or otherwise support components for performing the functions described in this disclosure).

[0114] In some examples, the communication manager 620 can be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise in cooperation with the receiver 610, the transmitter 615, or both. For example, the communication manager 620 can receive information from the receiver 610, send information to the transmitter 615, or be integrated in combination with the receiver 610, the transmitter 615, or both to receive information, transmit information, or perform various other operations as described herein.

[0115] For example, the communication manager 620 may be configured to or otherwise support components for associating a first port with multiple antenna elements of an antenna array, where the first port is based on a first linear precoding vector and has a first phase. The communication manager 620 may be configured to or otherwise support components for associating a second port with multiple antenna elements of an antenna array, where the second port is based on a second linear precoding vector and a phase shift such that the second port has a second phase that is coherent with the first phase. The communication manager 620 may be configured to or otherwise support components for applying the first linear precoding vector to a first input that includes a first combination of a first data set for a first UE and a second data set for a second UE. The communication manager 620 may be configured to or otherwise support components for applying the second linear precoding vector to a second input that includes a second combination of a first data set for a first UE and a second data set for a second UE. The communication manager 620 may be configured to or otherwise support components for transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0116] By including or configuring a communication manager 620 according to examples as described herein, a device 605 (e.g., a processor that controls or is otherwise coupled to a receiver 610, a transmitter 615, the communication manager 620, or a combination thereof) may support techniques for non-linear precoding for MU-MIMO communication, which may improve the reliability of data reception for transmissions to two UEs.

[0117] Figure 7 Block diagram 700 illustrates a device 705 that supports non-linear precoding for MU-MIMO communication, in accordance with aspects of the present disclosure. The device 705 may be an example of aspects of the device 605 or the base station 105 as described herein. The device 705 may include a receiver 710, a transmitter 715, and a communication manager 720. The device 705 may also include a processor. Each of these components may be in communication with each other (e.g., via one or more buses).

[0118] The receiver 710 may provide components for receiving information (such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to non-linear precoding for MU-MIMO communication)). The information may be passed to other components of the device 705. The receiver 710 may utilize a single antenna or a set of multiple antennas.

[0119] The transmitter 715 can provide components for transmitting signals generated by other components of the device 705. For example, the transmitter 715 can transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to non-linear precoding for MU-MIMO communication). In some examples, the transmitter 715 can be co-located with the receiver 710 in a transceiver module. The transmitter 715 can utilize a single antenna or a set of multiple antennas.

[0120] The device 705 or its various components can be examples of components for performing various aspects of non-linear precoding for MU-MIMO communication as described herein. For example, the communication manager 720 can include a first port component 725, a second port component 730, a first linear precoding component 735, a second linear precoding component 740, a data set transmission component 745, or any combination thereof. The communication manager 720 can be an example of aspects of the communication manager 620 as described herein. In some examples, the communication manager 720 or its various components can be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise in cooperation with the receiver 710, the transmitter 715, or both. For example, the communication manager 720 can receive information from the receiver 710, send information to the transmitter 715, or be integrated in combination with the receiver 710, the transmitter 715, or both to receive information, transmit information, or perform various other operations as described herein.

[0121] The first port component 725 can be configured to or otherwise support components for associating a first port with a plurality of antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase. The second port component 730 can be configured to or otherwise support components for associating a second port with a plurality of antenna elements of an antenna array, the second port being based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase. The first linear precoding component 735 can be configured to or otherwise support components for applying a first linear precoding vector to a first input that includes a first combination of a first data set for a first UE and a second data set for a second UE. The second linear precoding component 740 can be configured to or otherwise support components for applying a second linear precoding vector to a second input that includes a second combination of a first data set for a first UE and a second data set for a second UE. The data set transmission component 745 can be configured to or otherwise support components for transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0122] Figure 8FIG. 800 is a block diagram illustrating a communication manager 820 that supports non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure. The communication manager 820 may be an example of aspects of the communication manager 620, the communication manager 720, or both as described herein. The communication manager 820 or its various components may be examples of components for performing various aspects of non-linear precoding for MU-MIMO communication as described herein. For example, the communication manager 820 may include a first port component 825, a second port component 830, a first linear precoding component 835, a second linear precoding component 840, a data set transmission component 845, a constellation adjustment component 850, a coefficient generation component 855, a precoding channel component 860, a neural network component 865, or any combination thereof. Each of these components may communicate directly or indirectly with each other (e.g., via one or more buses).

[0123] The first port component 825 may be configured to or otherwise support components for associating a first port with a plurality of antenna elements of an antenna array, the first port based on a first linear precoding vector and having a first phase. The second port component 830 may be configured to or otherwise support components for associating a second port with a plurality of antenna elements of an antenna array, the second port based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase. The first linear precoding component 835 may be configured to or otherwise support components for applying a first linear precoding vector to a first input that includes a first combination of a first data set for a first UE and a second data set for a second UE. The second linear precoding component 840 may be configured to or otherwise support components for applying a second linear precoding vector to a second input that includes a second combination of a first data set for a first UE and a second data set for a second UE. The data set transmission component 845 may be configured to or otherwise support components for transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0124] In some examples, based on the second phase of the second port being coherent with the first phase of the first port, the first transmission beam and the second transmission beam interfere constructively. In some examples, the constellation adjustment component 850 may be configured to or otherwise support components for adjusting the constellation of a second data set based on a first data set.

[0125] In some examples, to support the adjustment, the constellation adjustment component 850 may be configured to or otherwise support components for adjusting the constellation of each symbol of a second data set based on a corresponding value indicated by each respective symbol of a first data set.

[0126] In some examples, the first constellation of the first data set includes a first QPSK constellation. In some examples, the constellation of the second data set is a second constellation and includes a second QPSK constellation, where adjusting the second constellation of the second data set includes marking the second QPSK constellation based on the first data set.

[0127] In some examples, the coefficient generation component 855 may be configured to or otherwise support components for generating a first set of coefficients indicative of a first combination of the first data set and the second data set based on one or more channel metrics, where applying the first linear precoding vector is based on generating the first set of coefficient sets. In some examples, the coefficient generation component 855 may be configured to or otherwise support components for generating a second set of coefficients indicative of a second combination of the first data set and the second data set based on one or more channel metrics, where applying the second linear precoding vector is based on generating the second set of coefficient sets.

[0128] In some examples, generating the first set of coefficients and generating the second set of coefficients are based on applying a neural network, the input of which includes one or more channel metrics.

[0129] In some examples, the one or more channel metrics include an estimate of the downlink precoding channel, the downlink SNR, the expected noise covariance at the downlink precoding channel, or a combination thereof.

[0130] In some examples, for supporting transmission, the precoding channel component 860 may be configured to or otherwise support components for transmitting on a first portion of a precoding channel generated by applying the first linear precoding vector to the propagation channel using a first transmission beam corresponding to a first port. In some examples, for supporting transmission, the precoding channel component 860 may be configured to or otherwise support components for transmitting on a second portion of a precoding channel generated by applying the second linear precoding vector to the propagation channel using a second transmission beam corresponding to a second port. In some examples, the precoding channel is a two-by-two spatial causal channel based on the second port having a second phase that is coherent with the first phase.

[0131] Figure 9FIG. showing a system 900 including a device 905 that supports non-linear precoding for MU-MIMO communication according to aspects of the present disclosure. The device 905 may be an example of the device 605, the device 705, or the base station 105 as described herein or include components of these devices. The device 905 may communicate wirelessly with one or more base stations 105, UEs 115, or any combination thereof. The device 905 may include components for two-way voice and data communication, which include components for transmitting and receiving communication, such as a communication manager 920, a network communication manager 910, a transceiver 915, an antenna 925, a memory 930, code 935, a processor 940, and an inter-station communication manager 945. These components may communicate electronically via one or more buses (e.g., bus 950) or otherwise be coupled (e.g., operatively, communicatively, functionally, electronically, electrically).

[0132] The network communication manager 910 may manage communication with the core network 130 (e.g., via one or more wired backhaul links). For example, the network communication manager 910 may manage the transmission of data communication for client devices, such as one or more UEs 115.

[0133] In some cases, the device 905 may include a single antenna 925. However, in some other cases, the device 905 may have more than one antenna 925, which are capable of simultaneously transmitting or receiving multiple wireless transmissions. As described herein, the transceiver 915 may communicate bidirectionally via one or more antennas 925, a wired link, or a wireless link. For example, the transceiver 915 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 915 may also include a modem for modulating packets to provide the modulated packets to one or more antennas 925 for transmission; and demodulating packets received from one or more antennas 925. The transceiver 915, or the transceiver 915 and one or more antennas 925, may be examples of the transmitter 615, the transmitter 715, the receiver 610, the receiver 710, or any combination thereof or components of these.

[0134] The memory 930 may include a random access memory (RAM) and a read-only memory (ROM). The memory 930 may store computer-readable, computer-executable code 935 including instructions that, when executed by the processor 940, cause the device 905 to perform the various functions described herein. The code 935 may be stored in a non-transitory computer-readable medium such as a system memory or another type of memory. In some cases, the code 935 may not be directly executable by the processor 940 but may cause a computer (e.g., when compiled and executed) to perform the functions described herein. In some cases, in addition, the memory 930 may further contain a basic input / output system (BIOS) that may control basic hardware or software operations, such as interactions with peripheral components or devices.

[0135] The processor 940 may include intelligent hardware devices (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks supporting non-linear precoding for MU-MIMO communication). For example, the device 905 or components of the device 905 may include the processor 940 and the memory 930 coupled to the processor 940, and the processor 940 and the memory 930 are configured to perform the various functions described herein.

[0136] The inter-station communication manager 945 may manage communication with other base stations 105 and may include a controller or a scheduler for cooperatively controlling communication with the UE 115 with other base stations 105. For example, the inter-station communication manager 945 may coordinate the scheduling of transmissions to the UE 115 for various interference suppression techniques such as beamforming or joint transmission. In some examples, the inter-station communication manager 945 may provide an X2 interface within the LTE / LTE-A radio communication network technology to provide communication between the base stations 105.

[0137] For example, the communication manager 920 may be configured to or otherwise support components for associating a first port with a plurality of antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase. The communication manager 920 may be configured to or otherwise support components for associating a second port with a plurality of antenna elements of the antenna array, the second port being based on a second linear precoding vector and a phase shift such that the second port has a second phase that is coherent with the first phase. The communication manager 920 may be configured to or otherwise support components for applying the first linear precoding vector to a first input that includes a first combination of a first data set for a first UE and a second data set for a second UE. The communication manager 920 may be configured to or otherwise support components for applying the second linear precoding vector to a second input that includes a second combination of a first data set for a first UE and a second data set for a second UE. The communication manager 920 may be configured to or otherwise support components for transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0138] By including or configuring the communication manager 920 according to the examples described herein, the device 905 may support techniques for non-linear precoding for MU-MIMO communication, which may improve the reliability of data reception for transmissions to two UEs.

[0139] In some examples, the communication manager 920 may be configured to use or otherwise cooperate with the transceiver 915, one or more antennas 925, or any combination thereof to perform various operations (e.g., receive, monitor, transmit). Although the communication manager 920 is shown as a separate component, in some examples, one or more functions described with reference to the communication manager 920 may be supported or performed by the processor 940, the memory 930, the code 935, or any combination thereof. For example, the code 935 may include instructions that may be executed by the processor 940 to cause the device 905 to perform various aspects of non-linear precoding for MU-MIMO communication as described herein, or the processor 940 and the memory 930 may be otherwise configured to execute or support such operations.

[0140] Figure 10 A flowchart illustrating a method 1000 for supporting non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure is shown. The operations of method 1000 may be implemented by a base station or components thereof as described herein. For example, the operations of method 1000 may be performed by a base station as described with reference to Figures 1 to 9The described base station 105 performs it. In some examples, the base station may execute a set of instructions to control the functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the described functions.

[0141] At 1005, the method may include associating a first port with a plurality of antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase. The operation of 1005 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1005 may be performed by a first port component 825 as described with reference to Figure 8 the first port component 825.

[0142] At 1010, the method may include associating a second port with a plurality of antenna elements of an antenna array, the second port being based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase. The operation of 1010 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1010 may be performed by a second port component 830 as described with reference to Figure 8 the second port component 830.

[0143] At 1015, the method may include applying a first linear precoding vector to a first input, the first input including a first combination of a first data set for a first UE and a second data set for a second UE. The operation of 1015 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1015 may be performed by a first linear precoding component 835 as described with reference to Figure 8 the first linear precoding component 835.

[0144] At 1020, the method may include applying a second linear precoding vector to a second input, the second input including a second combination of a first data set for a first UE and a second data set for a second UE. The operation of 1020 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1020 may be performed by a second linear precoding component 840 as described with reference to Figure 8 the second linear precoding component 840.

[0145] At 1025, the method may include transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port. The operation of 1025 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1025 may be performed by a data set transmission component 845 as described with reference to Figure 8 the data set transmission component 845.

[0146] Figure 11FIG. 1100 is a flow diagram illustrating a method 1100 that supports non-linear precoding for MU-MIMO communication in accordance with aspects of the present disclosure. Operations of method 1100 may be implemented by a base station or components thereof as described herein. For example, operations of method 1100 may be performed by base station 105 as described with reference to Figures 1 to 9 In some examples, the base station may execute a set of instructions to control functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the described functions.

[0147] At 1105, the method may include associating a first port with a plurality of antenna elements of an antenna array, the first port based on a first linear precoding vector and having a first phase. The operation of 1105 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operation of 1105 may be performed by a first port component 825 as described with reference to Figure 8 In some examples, aspects of the operation of 1105 may be performed by a first port component 825 as described with reference to

[0148] At 1110, the method may include associating a second port with a plurality of antenna elements of the antenna array, the second port based on a second linear precoding vector and a phase shift such that the second port has a second phase that is coherent with the first phase. The operation of 1110 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operation of 1110 may be performed by a second port component 830 as described with reference to Figure 8 In some examples, aspects of the operation of 1110 may be performed by a second port component 830 as described with reference to

[0149] At 1115, the method may include adjusting a constellation of a second data set based on a first data set. The operation of 1115 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operation of 1115 may be performed by a constellation adjustment component 850 as referenced in Figure 8 In some examples, aspects of the operation of 1115 may be performed by a constellation adjustment component 850 as referenced in

[0150] At 1120, the method may include applying the first linear precoding vector to a first input based on the adjusted constellation, the first input including a first combination of a first data set for a first UE and a second data set for a second UE. The operation of 1120 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operation of 1120 may be performed by a first linear precoding component 835 as described with reference to Figure 8 In some examples, aspects of the operation of 1120 may be performed by a first linear precoding component 835 as described with reference to

[0151] At 1125, the method may include applying the second linear precoding vector to a second input based on the adjusted constellation, the second input including a second combination of a first data set for a first UE and a second data set for a second UE. The operation of 1125 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operation of 1125 may be performed by a second linear precoding component 840 as described with reference to Figure 8performed by the second linear precoding component 840 described above.

[0152] At 1130, the method may include transmitting a first combination and a second combination using a first transmission beam corresponding to a first port and a second transmission beam corresponding to a second port. The operation of 1130 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1130 may be performed by the data set transmission component 845 described with reference to Figure 8 the data set transmission component 845 described above.

[0153] Figure 12 A flowchart illustrating a method 1200 that supports non - linear precoding for MU - MIMO communication in accordance with aspects of the present disclosure is shown. The operations of method 1200 may be implemented by a base station or its components as described herein. For example, the operations of method 1200 may be performed by the base station 105 described with reference to Figures 1 to 9 the base station 105 described above. In some examples, the base station may execute a set of instructions to control the functional elements of the base station to perform the described functions. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the described functions.

[0154] At 1205, the method may include associating a first port with a plurality of antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase. The operation of 1205 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1205 may be performed by the first port component 825 described with reference to Figure 8 the first port component 825 described above.

[0155] At 1210, the method may include associating a second port with a plurality of antenna elements of an antenna array, the second port being based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase. The operation of 1210 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1210 may be performed by the second port component 830 described with reference to Figure 8 the second port component 830 described above.

[0156] At 1215, the method may include generating a first set of coefficients indicating a first combination of a first data set and a second data set and a second set of coefficients indicating a second combination of the first data set and the second data set based on one or more channel metrics. The operation of 1215 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1215 may be performed by the coefficient generation component 855 referred to in Figure 8 the coefficient generation component 855 described above.

[0157] At 1220, the method can include applying a first linear precoding vector to a first input based on generating a first set of coefficients, the first input including a first combination of a first data set for a first UE and a second data set for a second UE. The operation at 1220 can be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1220 can be performed by a first linear precoding component 835 as described with reference to Figure 8 the first linear precoding component 835 described above.

[0158] At 1225, the method can include applying a second linear precoding vector to a second input based on generating a second set of coefficients, the second input including a second combination of a first data set for a first UE and a second data set for a second UE. The operation at 1225 can be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1225 can be performed by a second linear precoding component 840 as described with reference to Figure 8 the second linear precoding component 840 described above.

[0159] At 1230, the method can include transmitting the first combination and the second combination using a first transmission beam corresponding to a first port and a second transmission beam corresponding to a second port. The operation at 1230 can be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1230 can be performed by a data set transmission component 845 as described with reference to Figure 8 the data set transmission component 845 described above.

[0160] Figure 13 A flowchart illustrating a method 1300 that supports non - linear precoding for MU - MIMO communication in accordance with aspects of the present disclosure is shown. The operations of method 1300 can be implemented by a base station or its components as described herein. For example, the operations of method 1300 can be performed by a base station 105 as described with reference to Figures 1 to 9 the base station 105 described above. In some examples, the base station can execute a set of instructions to control functional elements of the base station to perform the described functions. Additionally or alternatively, the base station can use dedicated hardware to perform aspects of the described functions.

[0161] At 1305, the method can include associating a first port with a plurality of antenna elements of an antenna array, the first port being based on a first linear precoding vector and having a first phase. The operation at 1305 can be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1305 can be performed by a first port component 825 as described with reference to Figure 8 the first port component 825 described above.

[0162] At 1310, the method can include associating a second port with a plurality of antenna elements of an antenna array, the second port based on a second linear precoding vector and a phase shift such that the second port has a second phase that is coherent with a first phase. The operation of 1310 can be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation of 1310 can be performed by a second port assembly 830 as described with reference to Figure 8 the second port assembly 830 described above.

[0163] At 1315, the method can include applying a first linear precoding vector to a first input that includes a first combination of a first data set for a first UE and a second data set for a second UE. The operation of 1315 can be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation of 1315 can be performed by a first linear precoding assembly 835 as described with reference to Figure 8 the first linear precoding assembly 835 described above.

[0164] At 1320, the method can include applying a second linear precoding vector to a second input that includes a second combination of a first data set for a first UE and a second data set for a second UE. The operation of 1320 can be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation of 1320 can be performed by a second linear precoding assembly 840 as described with reference to Figure 8 the second linear precoding assembly 840 described above.

[0165] At 1325, the method can include transmitting on a first portion of a precoded channel generated by applying the first linear precoding vector to a propagation channel using a first transmission beam corresponding to a first port. The operation of 1325 can be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation of 1325 can be performed by a precoded channel assembly 860 as described with reference to Figure 8 the precoded channel assembly 860 described above.

[0166] At 1330, the method can include transmitting on a second portion of a precoded channel generated by applying the second linear precoding vector to a propagation channel using a second transmission beam corresponding to a second port. The operation of 1330 can be performed in accordance with the examples disclosed herein. In some examples, aspects of the operation of 1330 can be performed by a precoded channel assembly 860 as described with reference to Figure 8 the precoded channel assembly 860 described above.

[0167] An overview of aspects of the present disclosure is provided below:

[0168] Aspect 1: A method for wireless communication at a base station, the method comprising: associating a first port with a plurality of antenna elements of an antenna array, the first port being at least partially based on a first linear precoding vector and having a first phase; associating a second port with the plurality of antenna elements of the antenna array, the second port being at least partially based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; applying the first linear precoding vector to a first input, the first input comprising a first combination of a first data set for a first UE and a second data set for a second UE; applying the second linear precoding vector to a second input, the second input comprising a second combination of the first data set for the first UE and the second data set for the second UE; and transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

[0169] Aspect 2: The method according to aspect 1, wherein at least partially based on the second phase of the second port being coherent with the first phase of the first port, the first transmission beam and the second transmission beam interfere constructively.

[0170] Aspect 3: The method according to any one of aspects 1 to 2, the method further comprising: adjusting the constellation of the second data set at least partially based on the first data set.

[0171] Aspect 4: The method according to aspect 3, wherein the adjustment comprises: adjusting the constellation of each symbol of the second data set at least partially based on a corresponding value indicated by each respective symbol of the first data set.

[0172] Aspect 5: The method according to any one of aspects 3 to 4, wherein the first constellation of the first data set comprises a first QPSK constellation; and the constellation of the second data set is a second constellation and comprises a second QPSK constellation, wherein adjusting the second constellation of the second data set comprises at least partially adjusting the labeling of the second QPSK constellation based on the first data set.

[0173] Aspect 6: The method according to any one of Aspects 1 to 5, the method further comprising: generating a first set of coefficients indicative of the first combination of the first data set and the second data set at least partially based on one or more channel metrics, wherein applying the first linear precoding vector is at least partially based on generating the first set of coefficients; and generating a second set of coefficients indicative of the second combination of the first data set and the second data set at least partially based on the one or more channel metrics, wherein applying the second linear precoding vector is at least partially based on generating the second set of coefficients.

[0174] Aspect 7: The method according to Aspect 6, wherein generating the first set of coefficients and generating the second set of coefficients are at least partially based on the application of a neural network, the input of the neural network including the one or more channel metrics.

[0175] Aspect 8: The method according to any one of Aspects 6 to 7, wherein the one or more channel metrics include an estimate of a downlink precoding channel, a downlink SNR, a noise covariance expected at the downlink precoding channel, or a combination thereof.

[0176] Aspect 9: The method according to any one of Aspects 1 to 8, wherein the transmission further comprises: transmitting on a first portion of a precoding channel generated by applying the first linear precoding vector to a propagation channel using the first transmission beam corresponding to the first port; and transmitting on a second portion of the precoding channel generated by applying the second linear precoding vector to the propagation channel using the second transmission beam corresponding to the second port.

[0177] Aspect 10: The method according to Aspect 9, wherein the precoding channel is a two-by-two spatial causal channel in which the second port has a second phase coherent with the first phase at least partially.

[0178] Aspect 11: An apparatus, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method according to any one of Aspects 1 to 10.

[0179] Aspect 12: An apparatus, the apparatus comprising at least one component for performing the method according to any one of Aspects 1 to 10.

[0180] Aspect 13: A non-transitory computer-readable medium, the non-transitory computer-readable medium storing code, the code including instructions executable by a processor to perform the method according to any one of Aspects 1 to 10.

[0181] It should be noted that the methods described herein describe possible specific implementations, and the operations and steps can be rearranged or otherwise modified and other specific implementations are also possible. In addition, aspects from two or more methods can be combined.

[0182] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes and the LTE, LTE-A, LTE-A Pro, or NR terms may be used in most of the description, the techniques described herein can also be applied to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques can be applicable to various other wireless communication systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0183] The information and signals described herein can be represented using any of a variety of different technologies and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the specification can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0184] The various illustrative blocks and components described in connection with the disclosure herein can be implemented or executed with a general-purpose processor, DSP, ASIC, CPU, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor can be a microprocessor, but in an alternative, the processor can be any processor, controller, microcontroller, or state machine. The processor can also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0185] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions can be stored as one or more instructions or code on a computer-readable medium or transmitted through a computer-readable medium. Other examples and specific implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these items. The features implementing the functions can also be physically located at different positions, including being distributed such that individual parts of the functions are implemented at different physical locations.

[0186] Computer-readable media includes both non-transitory computer storage media and communication media, which includes any medium that facilitates the transfer of a computer program from one place to another. Non-transitory storage media can be any available media that can be accessed by a general or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disc read-only memory (CD-ROM) or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store the desired program code components in the form of instructions or data structures and that can be accessed by a general or special purpose computer, or a general or special purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically, while discs reproduce data optically using a laser. Combinations of the above are also included within the scope of computer-readable media.

[0187] As used herein (including in the claims), the "or" used in a list of items (e.g., a list of items accompanied by phrases such as "at least one of" or "one or more of") indicates an inclusive listing such that, for example, the listing of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Additionally, 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" can be based on condition A and condition B without departing from the scope of the present 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".

[0188] The term "determine" encompasses a variety of actions, and thus, "determine" can include operations, calculations, processing, derivation, research, lookup (such as by looking up in a table, database, or other data structure), ascertainment, and similar actions. Additionally, "determine" can include receiving (such as receiving information), accessing (such as accessing data in a memory), and similar actions. Additionally, "determine" can include parsing, selecting, choosing, establishing, and other such similar actions.

[0189] In the figures, similar components or features may have the same reference numeral. Additionally, various components of the same type can be distinguished by adding a dash and a second numeral used to differentiate between similar components after the reference numeral. If only the first reference numeral is used in the specification, the description can apply to any one of the similar components having the same first reference numeral regardless of the second reference numeral, or any other subsequent reference numerals.

[0190] The description set forth herein in connection with the figures describes example configurations and does not represent all examples that can be implemented or are within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration" and not "preferred" or "advantageous over other examples". The detailed description includes specific details for providing an understanding of the described technology. However, the technology can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0191] The present description is provided to enable a person of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to a person of ordinary skill in the art, and the general principles defined herein can be applied to other variations without departing from the scope of the present disclosure. Thus, the present 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 method for wireless communication at a base station, the method comprising: Associating a first port with a plurality of antenna elements of an antenna array, the first port being at least partially based on a first linear precoding vector and having a first phase; Associating a second port with the plurality of antenna elements of the antenna array, the second port being at least partially based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; Applying the first linear precoding vector to a first input, the first input comprising a first combination of a first data set for a first user equipment (UE) and a second data set for a second UE; Applying the second linear precoding vector to a second input, the second input comprising a second combination of the first data set for the first UE and the second data set for the second UE; And Transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

2. The method according to claim 1, wherein the first transmission beam and the second transmission beam interfere constructively at least partially based on the second phase of the second port being coherent with the first phase of the first port.

3. The method according to claim 1, the method further comprising: Adjusting the constellation of the second data set at least partially based on the first data set.

4. The method according to claim 3, wherein the adjustment comprises: Adjusting the constellation of each symbol of the second data set at least partially based on a corresponding value indicated by each respective symbol of the first data set.

5. The method according to claim 3, wherein: The first constellation of the first data set comprises a first quadrature phase shift keying (QPSK) constellation; and the constellation of the second data set is a second constellation and comprises a second QPSK constellation, wherein adjusting the second constellation of the second data set comprises at least partially adjusting the labeling of the second QPSK constellation based on the first data set.

6. The method according to claim 1, the method further comprising: Generating a first set of coefficients indicative of the first combination of the first data set and the second data set at least partially based on one or more channel metrics, wherein applying the first linear precoding vector is at least partially based on generating the first set of coefficients; And Generating a second set of coefficients indicative of the second combination of the first data set and the second data set at least partially based on the one or more channel metrics, wherein applying the second linear precoding vector is at least partially based on generating the second set of coefficients.

7. The method according to claim 6, wherein generating the first set of coefficients and generating the second set of coefficients are at least partially based on the application of a neural network, the input of the neural network comprising the one or more channel metrics.

8. The method according to claim 6, wherein the one or more channel metrics include an estimate of a downlink precoded channel, a downlink signal-to-noise ratio, a noise covariance expected at the downlink precoded channel, or a combination thereof.

9. The method according to claim 1, wherein the transmission further comprises: transmitting, using the first transmission beam corresponding to the first port, on a first portion of a precoded channel generated by applying the first linear precoding vector to a propagation channel; and transmitting, using the second transmission beam corresponding to the second port, on a second portion of the precoded channel generated by applying the second linear precoding vector to the propagation channel.

10. The method according to claim 9, wherein the precoded channel is a two-by-two spatial causal channel in which the second port has a second phase coherent with the first phase at least in part.

11. An apparatus for wireless communication, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and operative, when executed by the processor, to cause the apparatus to: associate a first port with a plurality of antenna elements of an antenna array, the first port being at least in part based on a first linear precoding vector and having a first phase; associate a second port with the plurality of antenna elements of the antenna array, the second port being at least in part based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; apply the first linear precoding vector to a first input, the first input comprising a first combination of a first data set for a first user equipment (UE) and a second data set for a second UE; apply the second linear precoding vector to a second input, the second input comprising a second combination of the first data set for the first UE and the second data set for the second UE; and transmit the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

12. The apparatus according to claim 11, wherein the first transmission beam and the second transmission beam interfere constructively, at least in part based on the second phase of the second port being coherent with the first phase of the first port.

13. The apparatus according to claim 11, wherein the instructions, when executed by the processor, are further operative to cause the apparatus to: adjust the constellation of the second data set at least in part based on the first data set.

14. The apparatus according to claim 13, wherein the instructions for adjustment are executable by the processor to cause the apparatus to: adjust the constellation of each symbol of the second data set at least in part based on a corresponding value indicated by each respective symbol of the first data set.

15. The apparatus according to claim 13, wherein: The first constellation of the first data set includes a first quadrature phase shift keying (QPSK) constellation; and the constellation of the second data set is a second constellation and includes a second QPSK constellation, wherein adjusting the second constellation of the second data set includes at least partially adjusting the symbols of the second QPSK constellation based on the first data set.

16. The apparatus according to claim 11, wherein the instructions are further executable by the processor to cause the apparatus to: generate a first set of coefficients indicative of the first combination of the first data set and the second data set at least partially based on one or more channel metrics, wherein applying the first linear precoding vector is at least partially based on generating the first set of coefficients; and generate a second set of coefficients indicative of the second combination of the first data set and the second data set at least partially based on the one or more channel metrics, wherein applying the second linear precoding vector is at least partially based on generating the second set of coefficients.

17. The apparatus according to claim 16, wherein generating the first set of coefficients and generating the second set of coefficients are at least partially based on the application of a neural network, the input of the neural network including the one or more channel metrics.

18. The apparatus according to claim 16, wherein the one or more channel metrics include an estimate of a downlink precoding channel, a downlink signal-to-noise ratio, an expected noise covariance at the downlink precoding channel, or a combination thereof.

19. The apparatus according to claim 11, wherein the instructions for transmission are further executable by the processor to cause the apparatus to: transmit on a first portion of a precoding channel generated by applying the first linear precoding vector to a propagation channel using the first transmission beam corresponding to the first port; and transmit on a second portion of the precoding channel generated by applying the second linear precoding vector to the propagation channel using the second transmission beam corresponding to the second port.

20. The apparatus according to claim 19, wherein the precoding channel is a two-by-two spatial causal channel in which the second port has a second phase coherent with the first phase.

21. An apparatus for wireless communication, the apparatus comprising: means for associating a first port with a plurality of antenna elements of an antenna array, the first port being at least partially based on a first linear precoding vector and having a first phase; means for associating a second port with the plurality of antenna elements of the antenna array, the second port being at least partially based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; means for applying the first linear precoding vector to a first input, the first input including a first combination of a first data set for a first user equipment (UE) and a second data set for a second UE; A component for applying the second linear precoding vector to a second input, the second input including a second combination of the first data set for the first UE and the second data set for the second UE; and A component for transmitting the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

22. The apparatus according to claim 21, wherein the first transmission beam and the second transmission beam interfere constructively at least in part based on the second phase of the second port being coherent with the first phase of the first port.

23. The apparatus according to claim 21, the apparatus further comprising: A component for adjusting the constellation of the second data set at least in part based on the first data set.

24. The apparatus according to claim 23, wherein the component for the adjustment comprises: A component for adjusting the constellation of each symbol of the second data set at least in part based on a corresponding value indicated by each corresponding symbol of the first data set.

25. The apparatus according to claim 23, wherein: The first constellation of the first data set includes a first quadrature phase shift keying constellation; and the constellation of the second data set is a second constellation and includes a second quadrature phase shift keying constellation, wherein adjusting the second constellation of the second data set includes adjusting the label of the second quadrature phase shift keying constellation at least in part based on the first data set.

26. The apparatus according to claim 21, the apparatus further comprising: A component for generating a first set of coefficients indicating the first combination of the first data set and the second data set at least in part based on one or more channel metrics, wherein applying the first linear precoding vector is at least in part based on generating the first set of coefficients; and A component for generating a second set of coefficients indicating the second combination of the first data set and the second data set at least in part based on the one or more channel metrics, wherein applying the second linear precoding vector is at least in part based on generating the second set of coefficients.

27. The apparatus according to claim 26, wherein generating the first set of coefficients and generating the second set of coefficients are at least in part based on the application of a neural network, the input of the neural network including the one or more channel metrics.

28. The apparatus according to claim 26, wherein the one or more channel metrics include an estimate of a downlink precoding channel, a downlink signal-to-noise ratio, an expected noise covariance at the downlink precoding channel, or a combination thereof.

29. The apparatus according to claim 21, wherein the component for the transmission further comprises: A component for transmitting on a first portion of a precoding channel generated by applying the first linear precoding vector to a propagation channel using the first transmission beam corresponding to the first port; and A component for transmitting on a second portion of a precoded channel generated by applying the second linear precoding vector corresponding to the second port to the propagation channel, using the second transmission beam corresponding to the second port.

30. A non-transitory computer-readable medium storing code including instructions executable by a processor to: associate a first port with a plurality of antenna elements of an antenna array, the first port being at least partially based on a first linear precoding vector and having a first phase; associate a second port with the plurality of antenna elements of the antenna array, the second port being at least partially based on a second linear precoding vector and a phase shift such that the second port has a second phase coherent with the first phase; apply the first linear precoding vector to a first input, the first input including a first combination of a first data set for a first user equipment (UE) and a second data set for a second UE; apply the second linear precoding vector to a second input, the second input including a second combination of the first data set for the first UE and the second data set for the second UE; and transmit the first combination and the second combination using a first transmission beam corresponding to the first port and a second transmission beam corresponding to the second port.

31. A computer program product including computer instructions that, when executed by a processor, cause the processor to perform the method according to any one of claims 1-10.

Images