WO2025170805A1 - Data transmission with polarization for massive mimo systems - Google Patents

Abstract

A network node transmits a first set of CSI-RSs to multiple terminals through a at least some antenna elements of a first set of antenna elements at a first polarization and a second set of CSI-RSs to the multiple terminals through at least some of a second set of antenna elements at a second polarization. The network node evaluates the CSI reports received from the multiple terminals to identify a first terminal reporting a sufficient channel quality at the first polarization and a second terminal reporting a sufficient channel quality at the second polarization. The network node transmits a multiplexed data signal having first data for the first terminal and second data for the second terminal using the same time-frequency resources where the first data is transmitted at the first polarization and the second data is transmitted at the second polarization.

Description

DATA TRANSMISSION WITH POLARIZATION FOR MASSIVE MIMO SYSTEMS

CLAIM OF PRIORITY

[0001] The present application claims priority to Provisional Application No. 63/549,849, entitled “Method to Transmit Data in Extremely Large Massive MIMO Systems”, filed February 5, 2024, assigned to the assignee hereof and hereby expressly incorporated by reference in their entirety.

FIELD

[0002] This invention generally relates to wireless communications and more particularly to data transmission with polarization for Massive MIMO systems

BACKGROUND

[0003] Many conventional wireless communication systems employ network nodes such as, base stations or gNBs, to transmit and receive wireless signal to and from terminals, such as user equipment (UE) devices. A network node may include an antenna array with multiple antenna elements. The antenna array is often part of an antenna system having a plurality of logical antenna ports that are mapped to the multiple antenna elements of the antenna array. Communication through the antenna array is often managed by precoding signals and adjusting parameters to manipulate the antenna pattern of the antenna array. In order to select the appropriate precoder and antenna parameters to maximize efficient communication with a terminal, a terminal measures reference signals transmitted by a network node and transmits a report to the network node. A technique employed in conventional systems includes sending Channel State Information Reference Signals (CSI-RSs) that are received and measured by the terminal where the network node sends a CSI-RS configuration message to the terminal. The CSI-RS configuration message includes Radio Resource Control (RRC) parameters that are applied to a standard-defined CSI-RS resource mapping scheme to determine the resources elements where the reference signals to be measured will be transmitted. For conventional systems, the standard-defined CSI- RS resource mapping scheme is defined by the 3GPP communication specification where the CSI-RS resource mapping scheme defines 18 different reference signal transmission schemes and where the standard-defined CSI-RS resource mapping scheme can be represented by a table having 18 rows and that supports transmission modes for transmitting reference signals for up to 32 logical antenna ports.

SUMMARY

[0004] A network node transmits a first set of CSI-RSs to multiple terminals through at least some antenna elements of a first set of antenna elements at a first polarization and a second set of CSI-RSs to the multiple terminals through at least some of a second set of antenna elements at a second polarization. The network node evaluates the CSI reports received from the multiple terminals to identify a first terminal reporting a sufficient channel quality at the first polarization and a second terminal reporting a sufficient channel quality at the second polarization. The network node transmits a multiplexed data signal having first data for the first terminal and second data for the second terminal using the same time-frequency resources where the first data is transmitted at the first polarization and the second data is transmitted at the second polarization.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1A is a block diagram of a system for an example of CSI-RS transmission to multiple terminals where a first CSI-RS has a first polarization and a second CSI-RS has a second polarization.

[0006] FIG. 1 B is a block diagram of the system for an example of CSI reporting from multiple terminals for the two CSI-RS transmissions.

[0007] FIG. 1 C is a block diagram of the system for an example of simultaneous data transmission to two terminals over a single set of time-frequency resources using two polarizations. [0008] FIG. 2 is a block diagram of an example of a base station suitable for use as a network node.

[0009] FIG. 3 is a block diagram of an example of a UE device suitable for use as a terminal device.

[0010] FIG. 4 is a block diagram of an example of an antenna system suitable for use as the antenna system.

[0011] FIG. 5 is a flow chart of an example of CSI-RS management and data multiplexing using multiple antenna polarizations.

[0012] FIG. 6 is a flow chart of an example of CSI reporting and data reception using two transmission polarizations.

DETAILED DESCRIPTION

[0013] In order to manage multiple-element antenna arrays, conventional systems use a standard-defined Channel State Information Reference Signal (CSI-RS) resource mapping scheme defined for up to 32 logical ports by at least one revision of the 3GPP communication specification to configure terminals to measure and provide CSI reports. As discussed above, the 3GPP communication specification defines a CSI-RS resource mapping scheme for up to 32 logical antenna ports that can be represented by a table having 18 rows. Such a CSI-RS resource mapping scheme is defined and discussed with reference to “Table 7. .2.5.3-1 : CSI-RS locations within a slot” in Release 18. The relationships and calculations of the standard-defined CSI-RS resource mapping scheme is known to each terminal. In order for the terminal to identify the resource elements used for a particular RS transmission, however, the terminal requires additional information. The additional information is provided by a network node in a Radio Resource Control (RRC) message that includes specific parameters to be applied by the terminal to the CSI-RS mapping scheme to determine the resource elements where the reference signals will be transmitted by the network node. These parameters are typically referred to as “RRC parameters”. Therefore, after a network node, such as a gNB, determines the reference signal transmission scheme to transmit to a terminal, the network node transmits, to the terminal, an RRC message including the RRC parameters for the CSI-RS resource mapping. The terminal, such as user equipment device (UE device), evaluates the parameters to identify which of the 18 possible RS transmission modes of the standard-defined CSI-RS resource mapping scheme is being used. The terminal then applies the RRC parameters to the identified transmission mode to determine the RS resource elements where the reference signals will be transmitted by the network node. The terminal receives and measures the reference signals transmitted via the resource elements and generates a CSI report for transmission to the network node.

[0014] Multiple-input multiple-output (MIMO) systems can significantly increase the throughput of wireless systems. As a result, MIMO is an integral part of 4th and 5th generation wireless systems. Some 5G systems employ MIMO systems with a large number of antennas which are often referred to as massive MIMO systems. Typically, a massive MIMO system is set up with Nt transmit and Nr receive antennas, also called Nt Transmit and Nr Receive (TR) antennas. A conventional 32 TR system consists of 32 baseband ports and 32 radio branches. In some situations, the number, Nt, of Transmit antennas may be different from the number, Nr, of receive antennas.

[0015] Some conventional massive MIMO systems, referred to as active antenna systems (AAS), can support 192 antenna elements (AE) deployed in a frequency range of 3-4 GHz, regardless of the number of TRs. An antenna panel with 192 antenna elements, for example, may include 8 columns and 2 rows with cross-polarization (i.e. (8x2x2x6=192 AE). Often, a 32 TR massive MIMO system includes a radio branch connected to 6 elements, referred to as subarrays. Beamforming may be performed at both the baseband and the antenna panel.

[0016] Massive MIMO systems are likely to be deployed at higher frequencies where a larger number of smaller antenna elements in an array may be deployed due to the shorter wavelength of the signals. Frequencies in the range of 7-20 GHz are being considered for allocation to terrestrial communication systems, for example.

[0017] In order to support the larger antenna arrays of extremely massive MIMO systems, the subarray size may be increased while maintaining the conventional number of radio branches to 32. For example, the subarray may be increased to 12 or 24 such that a 32 TR system could use a 1X12 subarray to support a 384 AE antenna array or use a 1X24 subarray to support a 768 AE antenna array. With an increased subarray size, however, antenna beams are narrow and produce many sidelobes that can cause interference to other terminals.

[0018] Unfortunately, these types of structures present limitations since the current 3GPP specification supports UEs with up to 32 CSI-RS ports. As a result, the terminal can only provide feedback for precoding/beamforming for up to 32 antenna ports. When extremely large, massive MIMO systems having more than 32 antenna ports (e.g., 64 TR or 128 TR), the performance improves in reciprocity-based massive MIMO systems. In codebook-based massive MIMO systems, however, the achievable gains are lower compared to the reciprocity-based systems because the terminal can only provide feedback for 32 antenna ports.

[0019] For the examples herein, however, large antenna array systems having more than 32 logical antenna ports achieve greater gains while utilizing the basic format of the conventional 32 port standard-defined CSI-RS resource mapping scheme at the terminal. The large antenna array is strategically divided into two distinct polarization domains, such as horizontal and vertical polarizations. By leveraging the unique properties of each polarization, it becomes possible to effectively double the feedback capacity without altering the existing hardware structure of the antenna array or the terminal. In addition, the techniques described herein provide advantages to antenna systems of any size. The polarization diversity provides another degree of freedom regardless of how many logical ports are used. For example, the techniques can be applied to Release 18 of 3GPP communication and earlier releases where the number of logical ports is less than 32 as well as providing advantages to Release 19 and later releases where the number or supported logical ports may be greater than 128.

[0020] A network node is any apparatus, equipment, device, or combination of devices, on the network side of the communication system that is connected to the communication network or is part of communication network. Some examples of a network node include a base station, a node B, an E-UTRA Node B, Evolved Node B, eNodeB, eNB, a New Generation eNB (ng-eNB), a gNodeB (also known as a gNB) in new radio (NR) technology, a macro station, pico station, and a femto station. The network node may form, or be a part of, the radio access network (RAN) that provides a connection between the core network and terminal communication devices. A RAN may be organized into three functional blocks including a Radio Unit (RU), a Distributed Unit (DU) and a Centralized Unit (CU). The RU transmits, receives, amplifies, and digitizes radio frequency signals and typically located near, or integrated into, the antenna. The DU and CU perform computations and/or processing to send and receive digitalized radio signals to and from the core network. The DU is typically located at or near the RU and the CU may be closer to the core network. The infrastructure or connection between the RU and the DU is often referred to as fronthaul and the infrastructure or connection between the DU and the CU is often referred to as a midhaul. The communication node, therefore, may perform the functions of one or more of the RU, DU and/or CU depending on the particular implementation.

[0021] A terminal communication device (terminal), such as a remote terminal and a relay terminal, is a communication device on the terminal side of the communication system and is sometimes referred to as user equipment (UE), a UE device, a terminal device, wireless mobile device, wireless communication device and other terms. Some examples of a terminal communication device include a mobile phone, a smart phone, a personal digital assistant (PDA), tablet, and laptop computer. In some situations, the terminal communication device is a machine type communication (MTC) communication device or Internet-of-Things (IOT) device. In addition, the terminal communication device may be, or may be a part of, a wearable device or a vehicle where the vehicle may be terrestrial vehicle, watercraft, or aircraft (including unmanned aerial vehicles). The terminal communication device, therefore, is any fixed, mobile, or portable equipment that performs the functions of the terminal device described herein.

[0022] FIG. 1A is a block diagram of a system 100 for an example of CSI-RS transmission to multiple terminals 101-105 where a first CSI-RS 126 has a first polarization and a second CSI-RS 128 has a second polarization. For the examples herein, one of the polarizations is a vertical polarization and the other polarization is a horizontal polarization. In some situations, other types of orthogonal polarizations may be used. [0023] A network node 112 includes an antenna system 114 with an antenna array 116 and an antenna processor 118, as well as other components (not shown). The antenna array 116 includes a plurality of physical antenna elements (AEs) 120 where a first set of AEs 122 have a first polarization and second set of AEs 124 have a second polarization that is orthogonal to the first polarization. Using two sets of AEs 122, 124 allows the use of a standard-defined CSI-RS resource mapping scheme maintained and used by the terminals for each set of AEs. As a result, larger antenna arrays can be efficiently utilized using the conventional, standard-defined CSI-RS resource mapping scheme. Therefore, the number (NLP) of logical antenna ports supported by the antenna system is greater than a number of logical antenna ports (MSLP) defined by a standard- defined CSI-RS resource mapping scheme maintained and used by the terminals. As discussed below with reference to FIG. 1 C, such an arrangement also increases spectral efficiency since two sets of data for two terminals can be transmitted over the same time-frequency resources with little or no interference.

[0024] The antenna system 114 at the network node 112 includes the antenna array 116 having multiple antenna elements 120 where the antenna array 116 is accessible to other communication components at the network node through the logical antenna ports. Generally, the number of antenna elements (NAE) of the antenna array 116 at the network node 112 may be greater than 32 and the number (NLP) of logical antenna ports is greater than 32 although the techniques discussed herein may be applied to any number of antenna ports and any number of antenna elements. The antenna array 116, therefore, may include any number of AEs that may be divided between the two sets of polarization in any ratio. The plurality of logical antenna ports is mapped to the multiple antenna elements 120 of the antenna array 116 by an antenna processor 118. The antenna processor 118 manages communication through the antenna array 116 by precoding signals and adjusting parameters to manipulate the antenna pattern of the antenna array 116. For the examples herein, the antenna array includes 384 AEs and each set of AEs includes 192 AEs. For the example, a maximum of 32 logical ports can be mapped to each set of AEs. Accordingly, each radio branch of a 32 TR is connected to six AEs such that 32 logical ports are mapped to each of the 32 1X6 subarrays in the first set of AEs and each radio branch of the other 32 TRs is connected to six AEs such that 32 logical ports are mapped to each of the 32 1X6 subarrays in the second set of AEs.

[0025] In order to select the appropriate precoder and antenna parameters to maximize efficient communication with the terminals 101 -105, the terminals 101 -105 measure reference signals transmitted by the network node 112 and transmit CSI reports to the network node which can be used by the network node 112 to adjust antenna parameters, signals and precoders. The network node 112 configures each terminal to receive and measure the reference signals and to report the results of the measurements in the CSI report. The reference signals are transmitted over selected resource elements within a time-frequency resource set arranged in resource blocks (RBs).

[0026] For the examples herein, the network node 112 configures each terminal 101- 105 to receive a first CSI-RS before transmitting the first CSI-RS through the first set of antenna elements 122. Pilot signals or reference signals are processed by the antenna processor 118 to generate the first set of CSI-RSs that are transmitted through the first set of AEs 122. The antenna processor 118 may perform several functions such as precoding, resource element mapping, inverse fast Fourier transform (IFFT) processing Digital to Analog (DAC) conversion, mixing, and amplification. The antenna processor 118 maps a first set of logical ports to the AEs and applies precoding to the reference signal to generate each first CSI-RS that is transmitted over a first set of time-frequency resources. For the example, a maximum of 32 logical ports are mapped to the AEs. As discussed with reference to FIG. 1 B, the terminals 101 -105 receive and measure the first CSI-RS, generate CSI report based on the measurements, and transmit the CSI report to the network node. As mentioned above, however, any number logical ports may be supported.

[0027] The network node 112 configures each terminal 101 -105 to receive a second CSI-RS before transmitting the second CSI-RS through the second set of antenna elements. A pilot signal or reference signal is processed by the antenna processor to generate the second CSI-RS that is transmitted through the second set of AEs to each terminal. The antenna processor 118 maps a second set of logical ports to the AEs and applies precoding to the reference signal to generate the second CSI-RS that is transmitted over a second set of time-frequency resources. For the examples herein, the first set of time-frequency resources are different from the second set of timefrequency resources. In some situations, however, the resources can be the same. Also, the CSI-RS resource mapping scheme used for the first CSI-RS may be different from the CSI-RS resource mapping scheme used for the second CSI-RS.

[0028] FIG. 1 B is a block diagram of the system 100 for an example of CSI reporting from multiple terminals for the two CSI-RS transmissions. Each terminal 101 -105 receives a first CSI-RS 126 transmitted from the network node 112 as discussed with reference to FIG. 1A. In accordance with the CSI configuration established by the network node 112, each terminal measures or otherwise evaluates the first CSI-RS 126 and generates a CSI report based on the measurements. Therefore, the first terminal 101 measures the first CSI-RS 126 in accordance with the configuration received in a configuration message from the network node 112 and generates a first terminal first CSI report 131. Since the first CSI-RS 126 is transmitted at the first polarization, the first terminal first CSI report 131 provides CSI information for the communication channel at the first polarization. Similarly, the second terminal 102 measures the first CSI-RS 126 in accordance with the configuration received in a configuration message from the network node 112 and generates a second terminal first CSI report 132. Since the first CSI-RS 126 is transmitted at the first polarization, the second terminal first CSI report 132 provides CSI information for the communication channel to the second terminal 102 at the first polarization. The other terminals 103-105 also provide CSI reports 133-135 based on the first CSI-RS 126. For the example, the CSI reports 131-135 include a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a Rank Indicator (Rl), a CSI-RS Resource Indicator (CRI) (i.e. , beam indicator). The CSI reports may include and combination of parameters and information. A CSI report may include additional information in some situations and/or the CQI, PMI, Rl, or CRI may be omitted.

[0029] In accordance with the CSI configuration established by the network node 112, each terminal 101-105 also measures or otherwise evaluates the second CSI-RS 128 and generates a CSI report based on the measurements. Therefore, the first terminal 101 measures the second CSI-RS 128 in accordance with the configuration received in a configuration message from the network node 112 and generates a first terminal second CSI report 141. Since the second CSI-RS 128 is transmitted at the second polarization, the first terminal second CSI report 141 provides CSI information for the communication channel at the second polarization. Similarly, the second terminal 102 measures the second CSI-RS 128 in accordance with the configuration received in a configuration message from the network node 112 and generates a second terminal second CSI report 142. Since the second CSI-RS 128 is transmitted at the second polarization, the second terminal second CSI report 142 provides CSI information for the communication channel to the second terminal 102 at the second polarization. The other terminals 103-105 also provide CSI reports 143-145 based on the second CSI-RS 128.

[0030] The CSI reports 131-135, 141 -145 are received at the network node 112 by a receiver 148 through at least some of the AEs 120 of the antenna array 114. In some situations, a separate receive antenna can be used instead of the antenna array 116. CSI report data for all of the CSI reports is forwarded to a controller 150 that at least evaluates and processes the reports to select terminal pairs for simultaneous data transmission and to select antenna configurations including precoding and communication resources for data transmissions. As discussed below, the controller 150 controls the antenna processor 118 to establish the antenna parameters of data transmissions including selection of the appropriate set of AEs for each data stream. The controller 150 may be implemented with any combination of hardware, software, and/or firmware for communicating with and controlling other transmitter, receiver and antenna components to execute the functions described herein. An example of suitable controller 150 includes code running on a microprocessor or processor arrangement connected to memory. The controller 150 may be at least a part of the antenna processor 118 or may share some components with the antenna processor 118.

Accordingly, some of the functions described as performed by the controller 150 may be performed by the antenna processor and vice versa. In addition, the antenna processor 118 and/or the controller 150 may be part of the electronics or controller facilitating the overall operation of the network node 112. [0031] FIG. 1 C is a block diagram of the system 100 for an example of simultaneous data transmission to two terminals over a single set of time-frequency resources 152 using two polarizations. The example of FIG. 1 C is continuation of the example of FIG. 1A and FIG. 1 B. Accordingly, the network node 112 transmits two CSI-RS signals using two different polarizations to multiple terminals 101-105 and receives CSI reports 131- 135, 141 -145 from the multiple terminals 101-105 based on the two CSI-RSs 126, 128. The controller (CSI report evaluator) 150 evaluates the CSI information to identify at least one terminal pair 154. For the example, the controller 150 identifies the first terminal 101 and the second terminal 102 as a terminal pair 154. The terminal pair is selected at least partially based on the CSI reports indicating a sufficient channel quality for each terminal 101 , 102 for different polarizations. In other words, the first terminal 101 provides a CSI report indicating a sufficient channel quality at one of the polarizations and the second terminal 102 provides a CSI report indicating a sufficient channel quality at the other polarization. For the example, the first terminal 101 indicates a preference for the first polarization and the second terminal 102 indicates a preference for the second polarization. In some situations, the network node 112 selects the terminal pair based on the best CQI values received in the CSI reports. In another situations, the network node selects the terminal pair 154 based on the best capacity by multiplying the Rl and the CQI.

[0032] The controller 150 in conjunction with the antenna processor 118 selects the time frequency resources and antenna configuration for a data transmission to the terminal pair 154 based on the CSI reports and other factors. Therefore, the controller 150 selects transmission parameters for the data transmission to both terminals 101 , 102, such as the time-frequency resources, precoder values, and CDM. A first data stream for the first terminal and a second data stream for the second terminal are processes by the antenna processor before each precoded, IFFT processed, analog converted, and amplified data stream is directed to the set of AEs providing the preferred polarization for the terminal receiving the data stream. The resulting two data signals 156, 158 are transmitted over the same set time-frequency resources 152 to the terminal pair 154 such that the first terminal receives the first data at the first polarization and the second terminal receives the second data at the second polarization. In some situations, only the time-frequency resources for both data streams are the same and other parameters are different. For example, a different CDM may be applied to each data stream to further increase isolation between the two data streams in addition to the isolation provided by the orthogonal polarizations.

[0033] For the example of FIG. 1 C, therefore, the first data stream is processed and transmitted as the first data signal 156 through the first set of AEs 122 with a first polarization and the second data stream is processed and transmitted as the second data signal 158 through the second set of AEs 124 at the second polarization.

[0034] By analyzing the CSI feedback, therefore, the network node 112 identifies which terminals exhibit a better channel response to a particular polarization. For example, if the first terminal 101 demonstrates a preference for horizontal polarization and second terminal 102 for demonstrates a preference for vertical polarization, the network node 112 can multiplex data for these two terminals 101 , 102 on the same frequency resources but on different polarizations. The network node 112 can determine the two terminals will experience no interference or minimal cross- polarization interference by projecting the PMI feedback of the terminals. This approach not only enhances spectral efficiency but also mitigates interference since the two polarizations inherently provide a level of isolation. As a result, such a dual-polarization strategy provides a substantial improvement in data throughput. By effectively multiplexing data for two terminals within the same spectral resources but under different polarizations, the system capitalizes on the underutilized potential of the existing antenna array. This not only maximizes the capacity of each frequency resource but also aligns with the evolving demands of high-data-rate communication networks.

[0035] The techniques discussed herein, therefore, may be applied to systems where the number (NLP) of logical antenna ports supported by the antenna system is greater than a number of logical antenna ports (MSLP) defined by the standard-defined CSI-RS resource mapping scheme maintained and used by the terminals. For the examples, the number of antenna elements (NAE) of the antenna array 116 at the network node 112 is greater than 32 and the number (NLP) of logical antenna ports is greater than 32. The antenna system 114 at the network node 112 includes the antenna array 116 having multiple antenna elements where the antenna array 116 is accessible to other communication components at the network node 112 through the logical antenna ports. The plurality of logical antenna ports is mapped to the multiple antenna elements of the antenna array 116. Communication through the antenna array 116 is managed by precoding signals and adjusting parameters to manipulate the antenna pattern of the antenna array 116. In order to select the appropriate precoder and antenna parameters to maximize efficient communication with a terminal, the terminal measures one or more reference signals transmitted by the network node 112 and transmits the CSI report to the network node 112 which can be used by the network node 112 to adjust antenna parameters, signals and precoders. The network node 112 configures the terminal to receive and measure the reference signals and to report the results of the measurements in the CSI report. The reference signals are transmitted over selected resource elements within a time-frequency resource set arranged in resource blocks (RBs). The network node 112 transmits CSI configuration messages that include Radio Resource Control (RRC) parameters that the terminal applies to the standard-defined CSI-RS resource mapping scheme maintained at the terminal. The terminal is preconfigured or otherwise configured with information defining the standard- defined CSI-RS resource mapping scheme before receiving a CSI-RS configuration message with RRC parameters. The terminal applies the RRC parameters to the standard-defined CSI-RS resource mapping scheme to at least determine the resource elements that will be used by the network node 112 to transmit the reference signals and that are to be measured by the terminal. The standard-defined CSI-RS resource mapping scheme maintained at the terminal is defined by at least one revision of the 3GPP communication specification where the standard-defined CSI-RS resource mapping scheme defines 18 different reference signal transmission modes and supports 32 logical antenna ports. As discussed above, the network node 112 is limited to receiving CSI reports from a terminal for 32 logical antenna ports in conventional systems. Accordingly, antenna systems with more than 32 logical antenna ports that utilize conventional techniques are unable to fully take advantage of the additional performance offered by antenna arrays including more than 32 antenna elements. For the examples herein, however, the network node 112 receives CSI reports providing feedback from more than 32 logical antenna ports even though the terminal is configured with the standard-defined CSI-RS resource mapping scheme for 32 logical ports. For the examples, 32 logical ports are mapped to each set of AEs 122, 124. Since signals form the first set of AEs 122 are transmitted at a different polarization form the polarization of the signals transmitted from the second set of AES 124, each terminal can provide a CSI report for each set of AEs separately. As a result, each terminal can provide feedback for 64 logical ports in the examples using a standard- defined CSI-RS resource mapping scheme for 32 logical ports. Such techniques can be expanded to larger antenna arrays and to a different number of logical ports.

[0036] FIG. 2 is a message diagram for an example of CSI reporting and data multiplexing using multiple antenna polarizations. One or more of the events or and transmissions may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 2. For example, in many situations, the CSI-RS configuration messages to the multiple terminals are transmitted at the same time. Similarly, the CSI-RSs may be transmitted at the same time to the multiple terminals using different time-frequency resources. In still further examples, additional transmissions and events may be added that are not explicitly described in connection with the example discussed with reference to FIG. 2.

[0037] At transmission 202, the network node sends a first terminal first CSI-RS configuration message to the first terminal 101 . For the example, the CSI-RS configuration message includes Radio Resource Control (RRC) parameters that are applied by a terminal to a standard-defined CSI-RS resource mapping scheme to determine the resources elements where the reference signals to be measured will be transmitted. A standard-defined CSI-RS resource mapping scheme is defined by the 3GPP communication specification where the CSI-RS resource mapping scheme defines 18 different reference signal transmission schemes and where the standard- defined CSI-RS resource mapping scheme can be represented by a table having 18 rows and that supports transmission modes for transmitting reference signals for up to 32 logical antenna ports. [0038] At transmission 204, the network node transmits a first terminal first CSI-RS. As discussed above, the first terminal first CSI-RS is transmitted through the first set of AEs 122 at the first polarization.

[0039] At event 206, the first terminal 101 receives and measures the first terminal first CSI-RS. The first terminal 101 applies the RRC parameters received in the first terminal first CSI-RS configuration message to the standard-defined CSI-RS resource mapping scheme to determine the time-frequency resources and other transmission characteristics of the first terminal first CSI-RS. The first terminal 101 receives and measures the first CSI-RS in accordance with the received configuration.

[0040] At transmission 208, the first terminal 101 generates and transmits a first terminal first CSI report to the network node 112. In accordance with the first terminal first CSI-RS configuration message, the first terminal 101 measures the parameters and performs any required calculations to generate the first terminal first CSI report. The first terminal first CSI report indicates the quality of the communication channel for the first polarization between the network node 112 and the first terminal 101 and includes CQI, PMI, Rl, and CRI for the first terminal first CSI-RS.

[0041] At transmission 210, the network node 112 sends a second terminal first CSI- RS configuration message to the second terminal 102. For the example, the CSI-RS configuration message includes RRC parameters that are applied by the second terminal to the standard-defined CSI-RS resource mapping scheme to determine the resources elements where the reference signals to be measured will be transmitted.

[0042] At transmission 212, the network node 112 transmits a second terminal first CSI-RS. As discussed above, the second terminal first CSI-RS is transmitted through the first set of AEs 122 at the first polarization. For the example, the second terminal first CSI-RS is transmitted at the same time as the first terminal first CSI-RS. For the example, therefore, the second terminal first CSI-RS is transmitted over time-frequency resources that are different from the time-frequency resources of the first terminal first CSI-RS. In some situations, however, at least some of the time-frequency resources may be the same for both transmissions. Such a situations may occur, for example, where a different CDM is applied to the same time-frequency resource for the two transmissions.

[0043] At event 214, the second terminal 102 receives and measures the second terminal first CSI-RS. The second terminal 102 applies the RRC parameters received in the second terminal first CSI-RS configuration message to the standard-defined CSI-RS resource mapping scheme to determine the time-frequency resources and other transmission characteristics of the first CSI-RS. The second terminal 102 receives and measures the second terminal first CSI-RS in accordance with the received configuration.

[0044] At transmission 216, the second terminal 102 generates and transmits a second terminal first CSI report to the network node 112. In accordance with the second terminal first CSI-RS configuration message, the second terminal measures the parameters and performs any required calculations to generate the second terminal first CSI report. The CSI report indicates the quality of the communication channel for the first polarization between the network node and the second terminal and includes CQI, PMI, Rl, and CRI.

[0045] At transmission 218, the network node 112 sends a first terminal second CSI- RS configuration message to the first terminal 101 . For the example, the fist terminal second CSI-RS configuration message includes RRC parameters that are applied by the terminal to the standard-defined CSI-RS resource mapping scheme to determine the resources elements where the reference signals to be measured will be transmitted.

[0046] At transmission 220, the network node 112 transmits a first terminal second CSI-RS. The first terminal second CSI-RS is transmitted through the second set of AEs 124 at the second polarization.

[0047] At event 222, the first terminal 101 receives and measures the first terminal second CSI-RS. The first terminal 101 applies the RRC parameters received in the first terminal second CSI-RS configuration message to the standard-defined CSI-RS resource mapping scheme to determine the time-frequency resources and other transmission characteristics of the first terminal second CSI-RS. The first terminal 101 receives and measures the first terminal second CSI-RS in accordance with the received configuration.

[0048] At transmission 224, the first terminal 101 generates and transmits a first terminal second CSI report to the network node 112. In accordance with the first terminal second CSI-RS configuration message, the first terminal 101 measures the parameters and performs any required calculations to generate the first terminal second CSI report. The first terminal second CSI report indicates the quality of the communication channel for the second polarization between the network node 112 and the first terminal 101 and includes CQI, PMI, Rl, and CRI for the first terminal second CSI-RS.

[0049] At transmission 226, the network node 112 sends a second terminal second CSI-RS configuration message to the second terminal 102. For the example, the CSI- RS configuration message includes RRC parameters that are applied by the second terminal to the standard-defined CSI-RS resource mapping scheme to determine the resources elements where the reference signals to be measured will be transmitted.

[0050] At transmission 228, the network node 112 transmits a second terminal second CSI-RS. The second terminal second CSI-RS is transmitted through the second set of AEs 124 at the second polarization.

[0051] At event 230, the second terminal 102 receives and measures the second terminal second CSI-RS. The second terminal 102 applies the RRC parameters received in the second terminal second CSI-RS configuration message to the standard- defined CSI-RS resource mapping scheme to determine the time-frequency resources and other transmission characteristics of the second CSI-RS. The second terminal 102 receives and measures the second terminal second CSI-RS in accordance with the received configuration.

[0052] At transmission 232, the second terminal 102 generates and transmits a second terminal second CSI report to the network node 112. In accordance with the second terminal second CSI-RS configuration message, the second terminal measures the parameters and performs any required calculations to generate the second terminal second CSI report. The CSI report indicates the quality of the communication channel for the second polarization between the network node and the second terminal 102 and includes CQI, PMI, Rl, and CRI.

[0053] In some situations, as discussed above, the network node transmits CSI configuration messages and CSI-RS to other terminals and received CSI reports from the other terminals in addition to the CSI reports from the first terminal 101 and second terminal 102.

[0054] At event 234, the network node 112 evaluates all the CSI reports from all of the terminals and identifies a terminal pair. The network node 112, therefore, evaluates the first terminal first CSI report, the first terminal second CSI report, the second terminal first CSI report, the second terminal second CSI report, and CSI reports from any additional terminals in the area. Based on at least the quality indicators for each CSI-RS determined for the different polarizations, the network node identifies two terminals that report sufficient channel quality at the two different polarizations. For the example, the network node identifies the first terminal 101 and the second terminal 102 as a terminal pair.

[0055] At transmission 236, first data for the first terminal and second data for the second terminal is transmitted over the same time-frequency resources. As discussed above, a first processed data stream 238 based on the first data is transmitted through the first set of AEs 122 and a second processed data stream 240 based on the second data is transmitted through the second set of AEs 122, where both data streams are transmitted over the same time-frequency resources. As result, the first data stream 238 is transmitted with the first polarization and the second data stream 240 is transmitted with the second polarization. The first terminal receives the first data stream with the first data and the second terminal recovered the second data stream with the second data.

[0056] For the example, some of the signals discussed above are transmitted simultaneously. For example, transmission 202 and transmission 208 may be transmitted at the same time. Transmission 204 and transmission 210 are transmitted simultaneously using different resources. In some situations where there is a high number of terminals and where time-frequency resources are limited, it may be advantageous to transmit a first set of CSI-RSs at the first polarization to a first group of terminals simultaneously with transmitting a first set of CSI-RSs at the second polarization to a second group of terminals. Subsequently, a second set of CSI-RSs are transmitted to the first group of terminals at the second polarization simultaneously with transmitting second set of CSI-RSs at the first polarization to the second group of terminals.

[0057] FIG. 3 is a block diagram of an example of a base station 300 suitable for use as a network node 102. The base station 300 includes electronics 304, a transmitter 306, a receiver 308, and the antenna system 114, as well as other electronics, hardware, and code. The base station 300 is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to the base station 300 and network node 102 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a single device, and the functions described as performed in any single device may be implemented over several devices. The base station 300 may be a fixed device or apparatus that is installed at a particular location at the time of system deployment. Examples of such equipment include fixed base stations or fixed transceiver stations. Although the base station may be referred to by different terms, the base station is typically referred to as a gNodeB or gNB when operating in accordance with one or more revisions of the 3GPP communication specification. In some situations, the base station 300 may be mobile equipment that is temporarily installed at a particular location. Some examples of such equipment include mobile transceiver stations that may include power generating equipment such as electric generators, solar panels, and/or batteries. Larger and heavier versions of such equipment may be transported by trailer. In still other situations, the base station 300 may be a portable device that is not fixed to any particular location.

[0058] The electronics 304 include any combination of hardware, software, and/or firmware for communicating with and controlling other base station components to execute the functions described herein as well as facilitating the overall functionality of the base station 300. The electronics 304, therefore, cooperatively operate with other base station 300 components to initiate tasks and perform the operations and functions of the base station 300. An example of suitable electronics 304 includes code running on a microprocessor or processor arrangement connected to memory 314. The electronics 304 may also be referred to as a controller. The transmitter 306 includes electronics configured to transmit wireless signals. In some situations, the transmitter 306 may include multiple transmitters. The receiver 308 includes electronics configured to receive wireless signals. In some situations, the receiver 308 may include multiple receivers. The receiver 308 may receive signals through multiple antennas or through a selected antenna of the antenna system 114. The antenna system 114 may include separate transmit and receive antennas in some situations.

[0059] The transmitter 306 and receiver 308 in the example of FIG. 3 perform radio frequency (RF) processing including modulation and demodulation. The receiver 308, therefore, may include components such as low noise amplifiers (LNAs) and filters. The transmitter 306 may include filters and amplifiers. Other components may include isolators, matching circuits, and other RF components. These components in combination or cooperation with other components perform the base station functions. The required components may depend on the particular functionality required by the base station 300.

[0060] The transmitter 306 includes a modulator (not shown), and the receiver 308 includes a demodulator (not shown). The modulator modulates the signals to be transmitted as part of the downlink signals and can apply any one of a plurality of modulation orders. The demodulator demodulates any uplink signals received at the base station 300 in accordance with one of a plurality of modulation orders. The electronics 304 in conjunction with the transmitter 306 apply a precoder matrix and a time domain beamforming matrix to signals transmitted through the multiple antennas 310.

[0061] The base station 300 includes a communication interface 312 for communicating with other base stations and other network components, and other entities, such as servers and databases. The communication interface 312 may be connected to a backhaul or network enabling communication with other base stations. In some situations, the link between base stations may include at least some wireless portions. The communication interface 312, therefore, may include wireless communication functionality and may utilize some of the components of the transmitter

306 and/or receiver 308.

[0062] The electronics 304, in conjunction with the receiver 308, measure and evaluate signals transmitted by UE devices (terminals). The electronics 304 and the receiver 308, therefore, can receive, measure, and evaluate uplink signals including reference signals transmitted by UE devices. Signal measurements and evaluations can be stored in a memory 314 and are used to determine the location of UE devices in some circumstances.

[0063] The electronics 304, in conjunction with the transmitter 306 and antenna system 114, process outgoing signals to precode signals transmitted to terminals (UE devices). Accordingly, the electronics 304, components of the antenna system 114, and transmitter 306 apply the appropriate precoder and beamforming to signals transmitted to specific UE devices. As discussed herein, the base station 300 may transmit reference signals and receive feedback from the terminals in order to determine the appropriate precoders, antenna system settings, and other transmission parameters. In some situations, the electronics 304 include one or more processors or other functional electronics sets. The electronics 304, therefore, may include (or otherwise perform the functions of) the controller 150 and the antenna processor 118 discussed above.

[0064] FIG. 4 is a block diagram of an example of a UE device 400 suitable for use as the terminal devices 108, 110. In some examples, the UE device 400 is any wireless communication device such as a mobile phone, a transceiver modem, a personal digital assistant (PDA), a tablet, or a smartphone. In other examples, the UE device 400 is a machine type communication (MTC) communication device or Internet-of-Things (IOT) device. The UE device 400, therefore is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to UE device 400 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a single device, and the functions described as performed in any single device may be implemented over several devices. [0065] The UE device 400 includes at least electronics 402, a transmitter 404 and a receiver 406. The electronics 402 include any combination of hardware, software, and/or firmware for communicating with and controlling other UE device components to execute the functions described herein as well as facilitating the overall functionality of a communication device. The electronics 402, therefore, cooperatively operate with other UE device components to initiate tasks and perform the operations and functions of the UE device 400. An example of suitable electronics 402 includes code running on a microprocessor or processor arrangement connected to memory 410. The electronics 402 may be referred to as a controller. The transmitter 404 includes electronics configured to transmit wireless signals. In some situations, the transmitter 404 may include multiple transmitters. The receiver 406 includes electronics configured to receive wireless signals. In some situations, the receiver 406 may include multiple receivers. The receiver 406 and transmitter 404 receive and transmit signals, respectively, through antenna 408. The antenna 408 may include separate transmit and receive antennas. In some circumstances, the antenna 408 may include multiple transmit and receive antennas.

[0066] The transmitter 404 and receiver 406 in the example of FIG. 3 perform radio frequency (RF) processing including modulation and demodulation. The receiver 406, therefore, may include components such as low noise amplifiers (LNAs) and filters. The transmitter 404 may include filters and amplifiers. Other components may include isolators, matching circuits, and other RF components. These components in combination or cooperation with other components perform the communication device functions. The required components may depend on the particular functionality required by the communication device.

[0067] The transmitter 404 includes a modulator (not shown), and the receiver 406 includes a demodulator (not shown). The modulator can apply any one of a plurality of modulation orders to modulate the signals to be transmitted as part of the uplink signals. The demodulator demodulates the downlink signals in accordance with one of a plurality of modulation orders.

[0068] The UE device 400 is capable of transmitting and receiving sidelink signals to and from other UE devices as well as communicating with base stations. The electron ics 402, in conjunction with the receiver 406, measure an evaluate signals transmitted by other devices, such as base stations and UE devices. The electronics 402 and the receiver 406, therefore, can receive, measure, and evaluate downlink reference signals transmitted by a base station. Signal measurements and evaluations can be stored in the memory 410.

[0069] FIG. 5 is a flow chart of an example of CSI-RS management and data multiplexing using multiple antenna polarizations. The method may be performed in a system such as the system 100 discussed herein. For the example, the method is performed by a network node, such as the network node 112. The method may be performed using any of several techniques involving any combination of software, hardware, and firmware. For example, software code running on electronics including a processor, computer or other processor arrangement within the network node may facilitate the generation, formatting, reception, and transmission of signals and messages as well as facilitating measurements, evaluations and determinations. One or more of the steps may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 5. In still further examples, additional steps may be added that are not explicitly described in connection with the example discussed with reference to FIG. 5.

[0070] At step 502, a first set of CSI configuration messages are transmitted to a plurality of terminals 101-105. The network node 112 configures each of the terminals 101-105 to receive and measure CSI-RSs with a CSI configuration message. For the example, each CSI configuration message of the first set of CSI configuration messages identifies the RRC parameters for reception of a CSI-RS transmitted with the first polarization.

[0071] At step 504, a first set of CSI-RSs are transmitted to the plurality of terminals 101-105 where each CSI-RS is transmitted at the first polarization. Each CSI-RS of the first set is transmitted through at least some of the AEs of the first set of AEs 122 at the first polarization. Each CSI-RS is transmitted to one of the terminals 101-105 in accordance with the CSI-RS configuration message transmitted to the particular terminal. For the example, the CSI-RSs of the first set are transmitted simultaneously and at least some of the time-frequency resources of each CSI-RS are different from the time-frequency resources of the other CSI-RSs of the first set.

[0072] At step 506, a first set of CSI reports are received from the plurality of terminals 101 -105. Each of the CSI reports provides the CSI based on the measurements of a CSI-RS by a terminal receiving the CSI-RS. The terminals 101-105 apply the RRC parameters received in the first set of CSI-RS configuration messages to the standard-defined CSI-RS resource mapping scheme to determine the timefrequency resources and other transmission characteristics of the CSI-RS received at each terminal. The terminals 101-105 receive and measure the first set of CSI-RSs in accordance with their respective configuration. For the example, each CSI report includes at least CQI, PMI, Rl, and CRI. The first set of CSI reports, therefore, provide feedback regarding the CSI-RSs received at the first polarization.

[0073] At step 508, a second set of CSI configuration messages are transmitted to the plurality of terminals 101-105. The network node 112 configures each of the terminals 101 -105 to receive and measure CSI-RSs with a CSI configuration message. For the example, each CSI configuration message of the second set of CSI configuration messages identifies the RRC parameters for reception of a CSI-RS transmitted with the second polarization.

[0074] At step 510, a second set of CSI-RSs are transmitted to the plurality of terminals 101 -105 where each CSI-RS is transmitted at the second polarization. Each CSI-RS of the second set is transmitted through at least some of the AEs of the second set of AEs 122 at the second polarization. Each CSI-RS is transmitted to one of the terminals 101 -105 in accordance with the CSI-RS configuration message transmitted to the particular terminal. For the example, the CSI-RSs of the second set are transmitted simultaneously and at least some of the time-frequency resources of each CSI-RS are different from the time-frequency resources of the other CSI-RSs of the second set.

[0075] At step 512, a second set of CSI reports are received from the plurality of terminals 101 -105. Each of the CSI reports provides the CSI based on the measurements of a CSI-RS by a terminal receiving the CSI-RS. The terminals 101-105 apply the RRC parameters received in the second set of CSI-RS configuration messages to the standard-defined CSI-RS resource mapping scheme to determine the time-frequency resources and other transmission characteristics of the CSI-RS received at each terminal. The terminals 101 -105 receive and measure the second set of CSI- RSs in accordance with their respective configuration. For the example, each CSI report includes at least CQI, PMI, Rl, and CRI. The second set of CSI reports, therefore, provide feedback regarding the CSI-RSs received at the second polarization.

[0076] At step 514, the network node 112 evaluates the first set of CSI reports and the second set of CSI reports and identifies one or more terminal pairs. Based on at least the quality indicators for each CSI-RS determined for the different polarizations, the network node 112 identifies two terminals that report sufficient channel quality at the two different polarizations.

[0077] At step 516, data for each terminal of an identified terminal pair is transmitted over the same time-frequency resources. As discussed above, for example, a first processed data stream 238 based on the first data is transmitted through the first set of AEs 122 and a second processed data stream 240 based on the second data is transmitted through the second set of AEs 122, where both data streams are transmitted over the same time-frequency resources. As result, the first data stream 238 is transmitted with the first polarization and the second data stream 240 is transmitted with the second polarization.

[0078] FIG. 6 is a flow chart of an example of CSI reporting and data reception using two transmission polarizations. The method may be performed in a system such as the system 100 discussed herein. For the example, the method is performed by a terminal, such as the first terminal 101 or the UE device 400. The method may be performed using any of several techniques involving any combination of software, hardware, and firmware. For example, software code running on electronics including a processor, computer or other processor arrangement within the terminal may facilitate the generation, formatting, reception, and transmission of signals and messages as well as facilitating measurements, evaluations and determinations. One or more of the steps may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 6. In still further examples, additional steps may be added that are not explicitly described in connection with the example discussed with reference to FIG. 6.

[0079] At step 602, a first CSI-RS configuration message is received. The terminal receives the first CSI-RS configuration message providing the RRC parameters for a first CSI-RS.

[0080] Ats step 604, the first CSI-RS at the first polarization is received and measured. The terminal applies the RRC parameters to the standard-defined CSI-RS resource mapping scheme to receive and measure the first CSI-RS transmitted at the first polarization from the network node 112.

[0081] At step 606, a CSI report is generated and transmitted to the network node 112. The terminal generates and transmits a CSI report based on the first CSI-RS. The CSI report includes at least CQI, PMI, Rl, and CRI. The first CSI report, therefore, provides feedback regarding the first CSI-RS received at the first polarization.

[0082] At step 608, a second CSI-RS configuration message is received. The terminal receives the second CSI-RS configuration message providing the RRC parameters for a second CSI-RS.

[0083] Ats step 610, the second CSI-RS at the second polarization is received and measured. The terminal applies the RRC parameters to the standard-defined CSI-RS resource mapping scheme to receive and measure the second CSI-RS transmitted at the second polarization from the network node 112.

[0084] At step 612, a CSI report is generated and transmitted to the network node 112. The terminal generates and transmits a second CSI report based on the second CSI-RS. The second CSI report includes at least CQI, PMI, Rl, and CRI. The second CSI report, therefore, provides feedback regarding the second CSI-RS received at the second polarization.

[0085] At step 614, data is received over time-frequency resources at a first polarization used for transmitting other data to another terminal. A first processed data stream based on the data for the terminal is transmitted through the first set of AEs 122 and another processed data stream based on the other data is transmitted through the second set of AEs 122, where both data streams are transmitted over the same timefrequency resources. As result, the first data stream is transmitted with the first polarization and the second data stream is transmitted with the second polarization.

Due to the isolation provided by the polarization, the terminal is able to receive the data without (or with minimal) interference.

[0086] To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. The described functionality may be implemented in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure. In accordance with various embodiments, a processor, device, component, circuit, structure, machine, module, etc. can be configured to perform one or more of the functions described herein. The term "configured to" or "configured for" as used herein with respect to a specified operation or function refers to processors, devices, components, circuits, electronics, and equipment that are physically constructed, programmed, instructed and/or arranged to perform the specified operation or function. Furthermore, the various illustrative logical blocks, modules, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), other electronics or combinations thereof, a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, electronics, and circuits can further include antennas and/or transceivers to communicate with various components within the network or within the device. A general-purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein. [0087] When implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer- readable medium. Computer readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0088] Therefore, the methods and apparatus of this invention may take the form, at least partially, of program logic or program code (i.e. , instructions) embodied in tangible media, such as a machine-readable storage medium. When the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. The methods and apparatus of the present invention may also be embodied in the form of program code that is transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via any other form of transmission. When the program code is received and loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates analogously to specific logic circuits.

[0089] Additionally, memory or other storage, as well as communication components, may be employed in embodiments of the present disclosure. It will be appreciated that, for clarity purposes, the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without detracting from the present disclosure. For example, functionality illustrated to be performed by separate processing logic elements, or controllers, may be performed by the same processing logic element, or controller. Therefore, references to specific functional units are only references to a suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization. [0090] Clearly, other embodiments and modifications of this invention will occur readily to those of ordinary skill in the art in view of these teachings. The above description is illustrative and not restrictive. This invention is to be limited only by the following claims, which include all such embodiments and modifications when viewed in conjunction with the above specification and accompanying drawings. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.

Claims

1 . A method comprising: transmitting, to each terminal of a plurality of terminals, a first Channel State Information Reference Signal (CSI-RS) at a first polarization; transmitting, to each terminal of the plurality of terminals, a second CSI-RS with a second polarization; receiving, from each of the plurality of terminals, a first CSI report providing CSI for the first CSI-RS and a second CSI report providing CSI for the second CSI-RS; identifying, based on the first CSI report and second CSI report from each terminal, a first terminal and a second terminal of the plurality of terminals; and transmitting, to the first terminal and to the second terminal, a multiplexed data signal comprising first data for the first terminal and second data for a second terminal, the multiplexed data signal transmitted over a single set of time-frequency resources, the first data transmitted at the first polarization and the second data transmitted at the second polarization.

2. The method of claim 1 , wherein the identifying the two terminals comprises: determining that CSI reports received from the first terminal and the second terminal indicate sufficient isolation due to polarization between a first channel to the first terminal and a second channel to the second terminal.

3. The method of claim 2, wherein the identifying the two terminals further comprises: determining a first terminal first CSI report received from the first terminal indicates a first channel quality of the first channel is above a threshold; and determining a second terminal second CSI report received from the second terminal indicates a second channel quality of the second channel is above a threshold.

4. The method of claim 1 , wherein transmitting the multiplexed data signal comprises: transmitting a first data stream including the first data through a first set of antenna elements at the first polarization; and transmitting a second data stream including the second data through a second set of antenna elements at the second polarization.

5. The method of claim 4, wherein each first CSI-RS is transmitted through at least some of the first set of antenna elements and each second CSI-RS is transmitted through at least some of the second set of antenna elements.

6. The method of claim 5, further comprising: mapping a first set of logical antenna ports to the first set of antenna elements, where the number of logical antenna ports of the first set of logical antenna ports is less than or equal to 32; and mapping a second set of a plurality of logical antenna ports to the second set of antenna elements, where the number of logical antenna ports of the second set of logical antenna ports is less than or equal to 32, wherein an antenna array comprises the first set of antenna elements and the second set of antenna elements.

7. The method of claim 5, further comprising: mapping a first set of logical antenna ports to the first set of antenna elements, where the number of logical antenna ports of the first set of logical antenna ports greater than 32; and mapping a second set of a plurality of logical antenna ports to the second set of antenna elements, where the number of logical antenna ports of the second set of logical antenna ports is greater than 32, wherein an antenna array comprises the first set of antenna elements and the second set of antenna elements.

8. The method of claim 7, wherein the number of logical antenna ports of the first set of logical antenna ports is greater than 128 and the number of logical antenna ports of the second set of logical antenna ports is greater than 128.

9. The method of claim 1 , wherein: transmitting each first CSI-RS comprises transmitting each first CSI-RS over time-frequency resources different from time-frequency resources of other first CSI- RSs; and transmitting each second CSI-RS comprises transmitting each second CSI-RS over time-frequency resources different from time-frequency resources of other second CSI-RSs.

10. The method of claim 9, wherein transmitting each first CSI-RS comprises transmitting each first CSI-RS over time-frequency resources different from timefrequency resources of the second CSI-RSs.

11. A method comprising: receiving, from a network node, a first Channel State Information Reference Signal (CSI-RS) at a first polarization; receiving, from the network node, a second CSI-RS at a second polarization; transmitting, to the network node, a first CSI report providing CSI for the first CSI- RS and a second CSI report providing CSI for the second CSI-RS; receiving a data signal with the first polarization, the data signal transmitted over time-frequency resources used for sending another data signal with the second polarization.

12. The method of claim 11 , further comprising: receiving a first CSI-RS configuration message comprising first Radio Resource Control (RRC) parameters; applying the first RRC parameters to a standard-defined CSI-RS resource mapping scheme to determine at least time-frequency resources of the first CSI-RS; receiving a second CSI-RS configuration message comprising second RRC parameters; applying the second RRC parameters to the standard-defined CSI-RS resource mapping scheme to determine at least time-frequency resources of the second CSI-RS.

13. The method of claim 12, wherein the standard-defined CSI-RS resource mapping scheme supports reference signals transmission schemes for up to 32 logical ports.

14. The method of claim 12, wherein the time-frequency resources of the second CSI-RS are different from the time-frequency resources of the first CSI-RS.

15. A terminal comprising: a receiver configured to receive, from a network node, a first Channel State Information Reference Signal (CSI-RS) at a first polarization and a second CSI-RS at a second polarization; a transmitter configured to transmit, to the network node, a first CSI report providing CSI for the first CSI-RS and a second CSI report providing CSI for the second CSI-RS, the receiver further configured to receive a data signal with the first polarization, the data signal transmitted over time-frequency resources used for sending another data signal with the second polarization.

16. The terminal of claim 15, further comprising a controller configured to apply first Radio Resource Control (RRC) parameters to a standard-defined CSI-RS resource mapping scheme to determine at least time-frequency resources of the first CSI-RS and to apply second RRC parameters to the standard-defined CSI-RS resource mapping scheme to determine at least time-frequency resources of the second CSI-RS, the receiver further configured to receive a first CSI-RS configuration message comprising the first RRC parameters and a second CSI-RS configuration message comprising the second RRC parameters.

17. The terminal of claim 16, wherein the standard-defined CSI-RS resource mapping scheme supports reference signals transmission schemes for up to 32 logical ports.

18. The terminal of claim 16, wherein the standard-defined CSI-RS resource mapping scheme supports reference signals transmission schemes for greater than 32 logical ports.

19. The terminal of claim 16, wherein the standard-defined CSI-RS resource mapping scheme supports reference signals transmission schemes for greater than 128 logical ports.

20. The terminal of claim 15, wherein the time-frequency resources of the second CSI-RS are different from the time-frequency resources of the first CSI-RS.