阅读说明：本技术 功率密度暴露控制 (Power density exposure control ) 是由 R·马利克 R·N·沙拉 J·H·朴 于 2020-04-30 设计创作，主要内容包括：本公开内容的各个方面通常涉及无线通信。在一些方面中,用户设备(UE)可以从UE能够使用UE的包括多个天线元件的天线阵列形成的多个波束中选择两个发送波束,其中,两个发送波束是要被用于发送对应的两个层的信息的；在选择两个发送波束之后,至少部分地基于两个发送波束来确定要被应用于两个发送波束的相位差；以及使用相位差,经由两个发送波束,在对应的两个层上同时地发送信息。提供了许多其它方面。(Various aspects of the present disclosure generally relate to wireless communications. In some aspects, a User Equipment (UE) may select two transmit beams from a plurality of beams that the UE is capable of forming using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used to transmit information of corresponding two layers; after selecting the two transmit beams, determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams; and transmitting information simultaneously on the corresponding two layers via the two transmission beams using the phase difference. Numerous other aspects are provided.)

1. A method of wireless communication performed by a User Equipment (UE), comprising:

selecting two transmit beams from among a plurality of beams that the UE can form using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers;

after selecting the two transmit beams, determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams; and

transmitting the information simultaneously on the corresponding two layers via the two transmit beams using the phase difference.

2. The method of claim 1, wherein the information on the corresponding two layers is transmitted via the two transmit beams using different polarizations on each of the two transmit beams.

3. The method of claim 1, wherein the phase difference is further determined based at least in part on respective transmit power levels to be used for the two transmit beams.

4. The method of claim 3, wherein the phase difference is a static value for the transmit power level.

5. The method of claim 1, wherein the phase difference is further determined based at least in part on a detection of a sensor of the UE, wherein the detection indicates whether a portion of a user of the UE is within a threshold proximity of an antenna element used to generate the two transmit beams.

6. The method of claim 1, wherein the phase difference is such that a power density exposure associated with the UE satisfies a threshold.

7. The method of claim 1, wherein the determined phase difference is such that a power density transmission of the UE conforms to a range of power density levels.

8. The method of claim 1, wherein the phase difference is a static value for the two transmit beams.

9. The method of claim 1, further comprising: storing, in a memory resource of the UE, information identifying the phase difference, wherein the phase difference is indexed in the memory resource in association with the information identifying the two transmit beams.

10. The method of claim 1, wherein determining the phase difference comprises randomly configuring the phase difference over time.

11. The method of claim 1, further comprising: applying the phase difference to the two transmit beams by adjusting phases of signals corresponding to the two transmit beams prior to transmitting the information on the corresponding two layers.

12. The method of claim 1, further comprising: applying the phase difference to the two transmit beams on time domain signal paths corresponding to the two transmit beams prior to transmitting the information on the corresponding two layers.

13. The method of claim 1, further comprising: applying the phase difference to the two transmit beams by configuring one or more Radio Frequency (RF) components associated with a transceiver of the UE prior to transmitting the information on the corresponding two layers.

14. The method of claim 13, wherein configuring the one or more RF components comprises: configuring the one or more RF components based at least in part on codebook entries for the two transmit beams.

15. The method of claim 14, wherein the phase difference is based at least in part on a relative phase between codewords corresponding to the two transmit beams from the codebook entry.

16. The method of claim 13, wherein configuring the one or more RF components comprises: configuring the one or more RF components based at least in part on adding the phase difference to phase shifters corresponding to the two transmit beams.

17. The method of claim 1, wherein the phase difference is across a plurality of ports corresponding to the two transmit beams.

18. The method of claim 1, wherein the phase difference is based at least in part on transmit antenna types of transmit antennas corresponding to the two transmit beams.

19. A User Equipment (UE) for wireless communication, comprising:

a memory; and

one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:

selecting two transmit beams from among a plurality of beams that the UE can form using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers;

after selecting the two transmit beams, determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams; and

transmitting the information simultaneously on the corresponding two layers via the two transmit beams using the phase difference.

20. The UE of claim 19, wherein the information on the corresponding two layers is transmitted via the two transmit beams using different polarizations on each of the two transmit beams.

21. The UE of claim 19, wherein the phase difference is further determined based at least in part on a detection of a sensor of the UE, wherein the detection indicates whether a portion of a user of the UE is within a threshold proximity of an antenna element used to generate the two transmit beams.

22. The UE of claim 19, wherein the phase difference is such that a power density exposure associated with the UE satisfies a threshold.

23. The UE of claim 19, wherein the phase difference is a static value for the two transmit beams.

24. The UE of claim 19, wherein the UE is configured to apply the phase difference to the two transmit beams by adjusting phases of signals corresponding to the two transmit beams prior to transmitting the information on the corresponding two layers.

25. The UE of claim 19, wherein the UE is configured to apply the phase difference to the two transmit beams on time domain signal paths corresponding to the two transmit beams prior to transmitting the information on the corresponding two layers.

26. The UE of claim 19, wherein the phase difference is across a plurality of ports corresponding to the two transmit beams.

27. A non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising:

one or more instructions that, when executed by one or more processors of a User Equipment (UE), cause the one or more processors to:

selecting two transmit beams from among a plurality of beams that the UE can form using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers;

after selecting the two transmit beams, determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams; and

transmitting the information simultaneously on the corresponding two layers via the two transmit beams using the phase difference.

28. The non-transitory computer-readable medium of claim 27, wherein the corresponding two layers are transmitted via the two transmit beams using different polarizations on each of the two transmit beams.

29. The non-transitory computer-readable medium of claim 27, wherein the phase difference is further determined based at least in part on a detection result of a sensor of the UE, wherein the detection result indicates whether a portion of a user of the UE is within a threshold proximity of an antenna element used to generate the two transmit beams.

30. An apparatus for wireless communication, comprising:

means for selecting two transmit beams from among a plurality of beams that the apparatus can form using an antenna array of the apparatus that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers;

means for determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams after selecting the two transmit beams; and

means for transmitting the information simultaneously on the corresponding two layers via the two transmit beams using the phase difference.

Technical Field

Aspects of the technology described below generally relate to wireless communications and techniques and apparatus for power density exposure control. Some techniques and apparatuses described herein implement and provide wireless communication devices and systems configured to contextually reduce user exposure to power density associated with use of a UE.

Background

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple-access techniques capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access techniques include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE) systems. LTE/LTE-Advanced (LTE-Advanced) is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the third generation partnership project (3 GPP).

A wireless communication network may include multiple Base Stations (BSs) that may support communication for multiple User Equipments (UEs). A User Equipment (UE) may communicate with a Base Station (BS) via a downlink and an uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. The BSs may be referred to as nodes B, gNB, Access Points (APs), radio heads, Transmit Receive Points (TRPs), New Radio (NR) BSs, 5G node BS, and so on.

Multiple access techniques have been adopted in various telecommunications standards. Wireless communication standards provide a common protocol to enable different devices (e.g., user equipment) to communicate on a municipal, national, regional, or even global level. A New Radio (NR), which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the third generation partnership project (3 GPP). As the demand for mobile broadband access continues to increase, further improvements in LTE and NR technologies are needed. These improvements may be applied to other multiple access techniques and telecommunications standards employing these techniques.

Disclosure of Invention

The following presents a simplified summary of some aspects of the disclosure in order to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended to neither identify key or critical elements of all aspects of the disclosure, nor delineate the scope of any or all aspects of the disclosure. The purpose of the summary is to present some concepts of one or more aspects of the disclosure in a simplified form as a prelude to the more detailed description that is presented later.

The 3GPP specifies the use of millimeter waves (mmW) as a carrier for fifth generation (5G) -New Radio (NR) systems. The 5G-NR mmW is a time division duplex system (TDD) and uses mmW for both uplink and downlink. The 5G-NR communication system is designed to maintain coverage with low power consumption. In the context of 5G-NR mmW, far-field radiation characteristics of the antenna module and placement of the antenna module in the UE are considered in the context of maintaining coverage with low power consumption. Some regulatory agencies set limits on millimeter wave Power Density (PD) exposure to human safety. Of interest are many: radio Frequency (RF) devices are configured with managed radiation emission, sometimes referred to as maximum allowable radio frequency exposure or specific adsorption rate. It is generally desirable for a device to prevent PD exposure beyond government-set limits when performing RF transmissions, such as mmW-related communications that may use a communication beam (e.g., a transmit beam and/or a receive beam).

NR frequency range 2(FR-2) supports multi-layer transmission (e.g., multi-beam transmission from a UE). Different layers are mapped to different transmit ports corresponding to different antennas. The antennas may be dual polarized (e.g., supporting polarized multiple-input multiple-output (MIMO)) or independent (e.g., supporting spatial MIMO). Various factors, including relative phase shifts between different ports, antennas, layers, etc., may affect the PD associated with the UE. In 3GPP, there is no specific requirement for the absolute value of the relative phase shift between different antenna ports, and the UE may not know the relative phase shift. Furthermore, in case the UE does not know the relative phase shift, the UE has to assume a worst case scenario for PD exposure. This limits the uplink transmit power of the UE to an uplink transmit power compatible with the worst case scenario.

Some techniques and apparatus described herein provide a UE capable of determining a relative phase difference between two transmit beams (e.g., a first beam and a second beam) to be transmitted from the UE based at least in part on a particular transmit beam included in the two transmit beams, a transmit power level to be used for the two transmit beams, and/or one or more other factors described herein. For example, the UE may determine the relative phase difference such that the PD exposure associated with the transmission of the two beams satisfies a threshold. In this way, the UE may reduce or eliminate excessive PD exposure to a user of the UE without having to assume a worst case scenario for PD exposure. This reduces or eliminates limitations on uplink transmit power that would otherwise occur due to having to assume a worst case scenario for PD exposure, thereby improving operation of the UE, improving communication between the UE and the wireless communication device, and so forth.

In some aspects, a method of wireless communication performed by a UE may comprise: selecting two transmit beams from a plurality of beams that the UE is capable of forming using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers. The method may include: after selecting the two transmit beams, determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams. The method may include: transmitting the information simultaneously on the corresponding two layers via the two transmit beams using the phase difference.

In some aspects, a UE for wireless communication may comprise: a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: selecting two transmit beams from a plurality of beams that the UE is capable of forming using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers. The memory and the one or more processors may be configured to: after selecting the two transmit beams, determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams. The memory and the one or more processors may be configured to: transmitting the information simultaneously on the corresponding two layers via the two transmit beams using the phase difference.

In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the UE and/or the one or more processors to: selecting two transmit beams from a plurality of beams that the UE is capable of forming using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers. The one or more instructions, when executed by the one or more processors of the UE, may cause the UE and/or the one or more processors to: after selecting the two transmit beams, determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams. The one or more instructions, when executed by the one or more processors of the UE, may cause the UE and/or the one or more processors to: transmitting the information simultaneously on the corresponding two layers via the two transmit beams using the phase difference.

In some aspects, an apparatus for wireless communication may include means for selecting two transmit beams from among a plurality of beams that the apparatus can form using an antenna array of the apparatus that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers. The apparatus may include means for determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams after selecting the two transmit beams. The apparatus may include means for simultaneously transmitting the information on the corresponding two layers via the two transmit beams using the phase difference.

As substantially described herein with reference to and as illustrated by the accompanying figures and description, aspects generally include methods, apparatuses, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and processing systems.

The foregoing has outlined rather broadly the features and technical advantages of examples according to the present disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The features of the concepts disclosed herein (both as to their organization and method of operation), together with the associated advantages, will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purpose of illustration and description and is not intended as a definition of the limits of the claims.

Drawings

In order that the above-recited features of the present disclosure can be understood in detail, a more particular description is provided herein, wherein certain aspects of the present disclosure are illustrated in the accompanying drawings. The drawings, however, illustrate only some aspects of the disclosure and are therefore not to be considered limiting of scope. The same reference numbers in different drawings may identify the same or similar elements.

Fig. 1 is a block diagram conceptually illustrating an example of a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 2 is a block diagram conceptually illustrating an example of a base station communicating with a UE in a wireless communication network, in accordance with various aspects of the present disclosure.

Fig. 3 is an example illustrating an architecture 300 that supports beamforming for millimeter wave (mmW) communication in accordance with various aspects of the present disclosure

Fig. 4-7 are diagrams illustrating one or more examples relating to power density exposure control in accordance with various aspects of the present disclosure.

Fig. 8 is a diagram illustrating an example process performed, for example, by a User Equipment (UE), in accordance with various aspects of the present disclosure.

Fig. 9 is a diagram illustrating another example process performed, for example, by a UE, in accordance with various aspects of the present disclosure.

Detailed Description

Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the present disclosure is intended to cover any aspect of the present disclosure disclosed herein, whether implemented independently or combined with any other aspect of the present disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the present disclosure is intended to cover such an apparatus or method practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

Several aspects of telecommunications systems will now be presented with reference to various devices and techniques. These apparatus and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements" or "features"). These elements may be implemented using hardware, software, or a combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

Although some aspects may be described herein using terms commonly associated with 3G and/or 4G wireless technologies, aspects of the disclosure may be applied in other generation-based communication systems (e.g., 5G and beyond (including NR technologies)).

While aspects and embodiments are described herein with the illustration of some examples, those of ordinary skill in the art will appreciate that additional implementations and use cases may occur in many different arrangements and scenarios. The innovations described herein may be implemented across many different platform types, devices, systems, shapes, sizes, packaging arrangements. For example, embodiments and/or uses may be implemented via integrated chip embodiments and/or other non-modular component-based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial devices, retail/procurement devices, medical devices, AI-enabled devices, etc.). While some examples may or may not be specific to use cases or applications, the innovations described may find wide applicability. Implementations may range from chip-level or modular components to non-modular, non-chip-level implementations, and further to aggregate, distributed, or Original Equipment Manufacturer (OEM) devices or systems that incorporate one or more aspects of the described innovations. In some practical arrangements, a device incorporating the described aspects and features must also include additional components and features for implementing and practicing the claimed and described embodiments. For example, the transmission and reception of wireless signals must include a number of components for analog and digital purposes (e.g., hardware components including one or more antennas, Radio Frequency (RF) chains, power amplifiers, modulators, buffers, processors, interleavers, summers/summers, etc.). It is intended that the innovations described herein may be implemented in a wide variety of devices, chip-scale components, systems, distributed arrangements, end-user devices, and the like, having different sizes, shapes, and configurations.

Fig. 1 is a diagram illustrating a wireless network 100 in which aspects of the present disclosure may be implemented. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. Wireless network 100 may include a plurality of BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A BS is an entity that communicates with User Equipment (UE) and may also be referred to as a base station, NR BS, node B, gNB, 5G node b (nb), access point, Transmission Reception Point (TRP), etc. Each BS may provide communication coverage for a particular area (e.g., a fixed or varying geographic area). In some scenarios, BS 110 may be stationary or non-stationary. In some non-stationary scenarios, the mobile BS 110 may move at varying speeds, directions, and/or altitudes. In 3GPP, the term "cell" can refer to a coverage area of BS 110 and/or a BS subsystem serving that coverage area, depending on the context in which the term is used.

The BS may provide communication coverage for a macrocell, a picocell, a femtocell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions. Additionally or alternatively, the BS may support access to unlicensed RF bands (e.g., Wi-Fi bands and/or the like). A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG)). The BS for the macro cell may be referred to as a macro BS. The BS for the pico cell may be referred to as a pico BS. The BS for the femto cell may be referred to as a femto BS or a home BS. In the example shown in fig. 1, BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102 c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "node B", "5G NB" and "cell" may be used interchangeably herein.

In some aspects, the cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of the mobile BS. In some aspects, BSs may be interconnected to each other and/or to one or more other BSs or network nodes (not shown) in wireless network 100 by various types of backhaul interfaces (e.g., direct physical connections, virtual networks, and/or the like using any suitable transport network). In other scenarios, the BS may be implemented in a Software Defined Network (SDN) manner or via Network Function Virtualization (NFV) manner.

Wireless network 100 may also include relay stations. A relay station is an entity that can receive a data transmission from an upstream station (e.g., a BS or a UE) and send the data transmission to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that is capable of relaying transmissions for other UEs. In the example shown in fig. 1, relay station 110d may communicate with macro BS 110a and UE120 d to facilitate communication between BS 110a and UE120 d. The relay station may also be referred to as a relay BS, a relay base station, a relay, etc.

The wireless network 100 may be a heterogeneous network including different types of BSs (e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.). These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in wireless network 100. For example, the macro BS may have a high transmit power level (e.g., 5 to 40 watts), while the pico BS, femto BS, and relay BS may have a lower transmit power level (e.g., 0.1 to 2 watts).

Network controller 130 may be coupled to a set of BSs and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via a backhaul. BSs may also communicate with one another, directly or indirectly, e.g., via a wireless or wired backhaul.

UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, mobile station, subscriber unit, station, etc. The UE may be a cellular telephone (e.g., a smartphone), a Personal Digital Assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop, a cordless phone, a Wireless Local Loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, ultrabooks, medical devices or apparatuses, biometric sensors/devices, wearable devices (smartwatches, smartclothing, smartglasses, smartwristbands, smartjewelry (e.g., smartrings, smartbracelets, etc.)), entertainment devices (e.g., music or video devices, or satellite radio units, etc.), vehicle components or sensors, smartmeters/sensors, industrial manufacturing devices, robots, drones, implantable devices, augmented reality devices, global positioning system devices, or any other suitable device configured to communicate via a wireless or wired medium.

Some UEs may be considered Machine Type Communication (MTC) UEs or evolved or enhanced machine type communication (eMTC) UEs. MTC UEs and eMTC UEs include, for example, a robot, a drone, a remote device, a sensor, a meter, a monitor, a location tag, etc., which may communicate with a base station, another device (e.g., a remote device), or some other entity. The wireless node may provide a connection to or to a network (e.g., a wide area network such as the internet or a cellular network), for example, via a wired or wireless communication link. Some UEs may be considered internet of things (IoT) devices and/or may be implemented as NB-IoT (narrowband internet of things) devices. Some UEs may be considered Customer Premises Equipment (CPE). UE120 may be included inside a housing that houses components of UE120, such as a processor component, a memory component, and the like. These components may be integrated in various combinations and/or may be separate distributed components, taking into account design constraints and/or operational preferences.

In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular RAT and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, a frequency channel, etc. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

In some aspects, two or more UEs 120 (e.g., shown as UE120 a and UE120 e) may communicate directly using one or more sidelink channels (e.g., without using base station 110 as an intermediary to communicate with each other). For example, the UE120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, vehicle-to-anything (V2X) protocols (e.g., which may include vehicle-to-vehicle (V2V) protocols, vehicle-to-infrastructure (V2I), etc.), mesh networks, and/or the like. In this case, UE120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by base station 110. In these deployment scenarios, the UE performing the scheduling operation may include or perform base station-like functionality.

As noted above, fig. 1 is provided by way of example only. Other examples may differ from the example described with respect to fig. 1.

Fig. 2 shows a block diagram of a design 200 of base station 110 and UE120 (which may be one of the base stations and one of the UEs in fig. 1). The base station 110 may be equipped with T antennas 234a through 234T and the UE120 may be equipped with R antennas 252a through 252R, where T ≧ 1 and R ≧ 1 in general. The T and R antennas may be configured with multiple antenna elements formed in an array for MIMO or massive MIMO deployment, which may occur in millimeter wave (mmWave or mmW) communication systems.

At base station 110, transmit processor 220 may perform many functions associated with communication. For example, transmit processor 220 may receive data for one or more UEs from data source 212, select one or more Modulation and Coding Schemes (MCSs) for each UE based at least in part on a Channel Quality Indicator (CQI) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-Static Resource Partitioning Information (SRPI), etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), as well as provide overhead symbols and control symbols. Transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS)) and synchronization signals (e.g., Primary Synchronization Signals (PSS) and Secondary Synchronization Signals (SSS)). A Transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T Modulators (MODs) 232a through 232T. Each modulator 232 may process a respective output symbol stream (e.g., for Orthogonal Frequency Division Multiplexing (OFDM), etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232a through 232T may be transmitted via T antennas 234a through 234T, respectively. According to certain aspects described in more detail below, a synchronization signal may be generated using position coding to convey additional information.

At UE120, antennas 252a through 252r may receive the downlink RF signals. The downlink RF signals may be received from one or more base stations 110 and/or transmitted by one or more base stations 110. The signals may be provided to demodulators (DEMODs) 254a through 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a through 254R, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE120 to a data sink 260, and provide decoded control information and system information to a controller/processor 280. The channel processor may determine Reference Signal Received Power (RSRP), Received Signal Strength Indicator (RSSI), Reference Signal Received Quality (RSRQ), Channel Quality Indicator (CQI), and the like. In some aspects, one or more components of UE120 may be included in a housing.

For uplink communications, UE120 may transmit control information and/or data to another device, such as one or more base stations 110. For example, at UE120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller/processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.). Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to base station 110. At base station 110, the uplink signals from UE120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by a MIMO detector 236 (if applicable), and further processed by a receive processor 238 to obtain the decoded data and control information sent by UE 120. Receive processor 238 may provide decoded data to a data sink 239 and decoded control information to controller/processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. Network controller 130 may include a communication unit 294, a controller/processor 290, and a memory 292.

Controller/processor 240 of base station 110, controller/processor 280 of UE120, and/or any other component of fig. 2 may perform one or more techniques associated with power density exposure control, as described in more detail elsewhere herein. For example, controller/processor 240 of base station 110, controller/processor 280 of UE120, and/or any other component of fig. 2 may perform or direct, for example, operations of process 800 of fig. 8, process 900 of fig. 9, and/or other processes described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE120, respectively. A scheduler 246 may schedule UEs for data transmission on the downlink and/or uplink.

In some aspects, UE120 may include various units or components for implementing communication functions. For example, the various units may include: means for determining a relative phase difference to be applied to two transmit beams of a UE based at least in part on a particular transmit beam included in the two transmit beams or a transmit power level to be used for the two transmit beams; means for transmitting two transmit beams to the wireless communication device after determining a relative phase difference, wherein the relative phase difference is applied to the two transmit beams; and so on. Additionally or alternatively, the various units may include: means for selecting two transmit beams from among a plurality of beams that the UE can form using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers; means for determining a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams after selecting the two transmit beams; means for simultaneously transmitting information on the corresponding two layers via the two transmission beams using the phase difference; and so on.

In some aspects, UE120 may include various structural components for performing the functions of various units. For example, structural components that perform the functions of such means may include one or more components of UE120 described in connection with fig. 2, e.g., antennas 252, DEMOD 254, MOD 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, controller/processor 280, and/or the like. Additionally or alternatively, the structural components that perform the functions of such units may include one or more components of UE120 described below in connection with fig. 3.

In some aspects, base station 110 may include various structural components for performing the functions of various units. For example, structural components that perform the functions of such means may include one or more components of base station 110 described in connection with fig. 2, e.g., transmit processor 220, TX MIMO processor 230, DEMOD 232, MOD 232, antenna 234, MIMO detector 236, receive processor 238, controller/processor 240, and/or the like.

As noted above, fig. 2 is provided by way of example only. Other examples may differ from the example described with respect to fig. 2.

Fig. 3 illustrates an example of an architecture 300 that supports beamforming for millimeter wave (mmW) communication in accordance with various aspects of the present disclosure. In some examples, the architecture 300 may implement aspects of a wireless communication system described herein. In some aspects, fig. 3 may illustrate an example of a transmitting device (e.g., a first wireless device, UE, or BS) and/or a receiving device (e.g., a second wireless device, UE, or BS) as described herein.

In general, fig. 3 is a diagram illustrating example hardware components of a wireless device in accordance with certain aspects of the present disclosure. The illustrated components may include components that may be used for antenna element selection and/or for beamforming for wireless signal transmission. There are many architectures for antenna element selection and phase shifting implementation, only one of which is illustrated here. Architecture 300 includes a modem (modulator/demodulator) 302, a digital-to-analog converter (DAC)304, a first mixer 306, a second mixer 308, and a splitter 310. The architecture 300 also includes a plurality of first amplifiers 312, a plurality of phase shifters 314, a plurality of second amplifiers 316, and an antenna array 318 including a plurality of antenna elements 320. Transmission lines or other waveguides, wires, traces, etc. connecting the various components are shown to illustrate how signals to be transmitted propagate between the components. Blocks 322, 324, 326 and 328 represent regions in the architecture 300 where different types of signals are propagated or processed. In particular, block 322 represents a region in which a digital baseband signal propagates or is processed, block 324 represents a region in which an analog baseband signal propagates or is processed, block 326 represents a region in which an analog Intermediate Frequency (IF) signal propagates or is processed, and block 328 indicates a region in which an analog Radio Frequency (RF) signal propagates or is processed. The architecture also includes a local oscillator a330, a local oscillator B332, and a beam management component 334.

Each antenna element 320 may include one or more sub-elements (not shown) for radiating or receiving RF signals. For example, a single antenna element 320 may include a first subelement that is cross-polarized with a second subelement that may be used to independently transmit cross-polarized signals. The antenna elements 320 may include patch antennas or other types of antennas arranged in a linear pattern, a two-dimensional pattern, or another pattern. The spacing between the antenna elements 320 may be such that signals of desired wavelengths separately transmitted by the antenna elements 320 may interact or interfere (e.g., to form a desired beam). For example, given a desired wavelength or frequency range, the spacing may provide a quarter wavelength, half wavelength, or other portion of the spacing between adjacent antenna elements 320 to allow for interaction or interference of signals transmitted by the separate antenna elements 320 within the desired range.

The modem 302 processes and generates digital baseband signals and may also control the operation of the DAC 304, the first and second mixers 306, 308, the splitter 310, the first amplifier 312, the phase shifter 314, and/or the second amplifier 316 to transmit signals via one or more or all of the antenna elements 320. Modem 302 may process signals and control operations in accordance with a communication standard, such as the wireless standard discussed herein. DAC 304 may convert digital baseband signals received from (and to be transmitted by) modem 302 to analog baseband signals. The first mixer 306 up-converts the analog baseband signal to an analog IF signal within the IF using local oscillator a 330. For example, the first mixer 306 may mix the signal with an oscillating signal generated by local oscillator a330 to "move" the baseband analog signal to IF. In some cases, some processing or filtering (not shown) may be performed at the IF. The second mixer 308 upconverts the analog IF signal to an analog RF signal using a local oscillator B332. Similar to the first mixer, the second mixer 308 may mix the signal with an oscillating signal generated by the local oscillator B332 to "shift" the IF analog signal to RF, or a frequency at which the signal is to be transmitted or received. Modem 302 and/or beam management component 334 may adjust the frequency of local oscillator a330 and/or local oscillator B332 such that the desired IF and/or RF frequencies are generated and used to facilitate processing and transmitting signals within the desired bandwidth.

In the illustrated architecture 300, the signal upconverted by the second mixer 308 is split or replicated into multiple signals by a splitter 310. Splitter 310 in architecture 300 splits the RF signal into a plurality of identical or nearly identical RF signals, as indicated by the presence in its block 328. In other examples, any type of signal including a baseband digital signal, a baseband analog signal, or an IF analog signal may be split. Each of these signals may correspond to an antenna element 320, and the signals propagate through amplifiers 312, 316, phase shifters 314, and/or other elements corresponding to the respective antenna element 320 and are processed to be provided to and transmitted by the corresponding antenna element 320 of the antenna array 318. In one example, the splitter 310 may be an active splitter that is connected to a power supply and provides a gain such that the RF signal exiting the splitter 310 is at a power level equal to or greater than the signal entering the splitter 310. In another example, the splitter 310 is a passive splitter that is not connected to a power source, and the RF signal exiting the splitter 310 may be at a lower power level than the RF signal entering the splitter 310.

After being split by the splitter 310, the resulting RF signal may enter an amplifier (such as the first amplifier 312) or a phase shifter 314 corresponding to the antenna element 320. The first and second amplifiers 312, 316 are illustrated with dashed lines, as one or both of them may not be needed in some implementations. In one implementation, both the first amplifier 312 and the second amplifier 316 are present. In another implementation, neither the first amplifier 312 nor the second amplifier 316 is present. In other implementations, one of the two amplifiers 312, 316 is present, but the other is not. For example, if the splitter 310 is an active splitter, the first amplifier 312 may not be used. As a further example, if phase shifter 314 is an active phase shifter capable of providing gain, second amplifier 316 may not be used. The amplifiers 312, 316 may provide a desired level of positive or negative gain. Positive gain (positive dB) may be used to increase the amplitude of the signal radiated by a particular antenna element 320. Negative gain (negative dB) may be used to reduce the amplitude and/or suppress the radiation of signals by a particular antenna element. Each of the amplifiers 312, 316 may be independently controlled (e.g., by the modem 302 or beam management component 334) to provide independent control of the gain for each antenna element 320. For example, modem 302 and/or beam management component 334 may have at least one control line connected to each of splitter 310, first amplifier 312, phase shifter 314, and/or second amplifier 316, which may be used to configure the gain to provide a desired amount of gain for each component and thus for each antenna element 320.

The phase shifter 314 may provide a configurable phase shift or phase offset to the corresponding RF signal to be transmitted. Phase shifter 314 may be a passive phase shifter that is not directly connected to a power source. Passive phase shifters may introduce some insertion loss. The second amplifier 316 may boost the signal to compensate for insertion loss. Phase shifter 314 may be an active phase shifter connected to a power supply such that the active phase shifter provides a certain amount of gain or prevents insertion loss. The settings of each phase shifter 314 are independent, meaning that each phase shifter may be independently set to provide a desired amount of phase shift or the same amount of phase shift or some other configuration. The modem 302 and/or the beam management component 334 may have at least one control line connected to each phase shifter 314 that may be used to configure the phase shifters 314 to provide a desired amount of phase shift or phase offset between the antenna elements 320.

In the illustrated architecture 300, RF signals received by the antenna elements 320 are provided to one or more first amplifiers 356 to enhance signal strength. The first amplifier 356 may be connected to the same antenna array 318, e.g., for TDD operation. The first amplifier 356 may be connected to a different antenna array 318. The enhanced RF signals are input into one or more phase shifters 354 to provide a configurable phase shift or phase offset for the corresponding received RF signals to enable reception via one or more Rx beams. Phase shifter 354 may be an active phase shifter or a passive phase shifter. The settings of phase shifters 354 are independent, meaning that each phase shifter may be independently set to provide a desired amount of phase shift or the same amount of phase shift or some other configuration. The modem 302 and/or the beam management component 334 may have at least one control line connected to each phase shifter 354 that may be used to configure the phase shifters 354 to provide a desired amount of phase shift or phase offset between the antenna elements 320 to allow reception via one or more Rx beams.

The output of the phase shifter 354 may be input to one or more second amplifiers 352 for signal amplification of the phase shifted received RF signal. The second amplifier 352 may be configured separately to provide a configured amount of gain. The second amplifier 352 may be configured separately to provide a certain amount of gain to ensure that the signals input to the combiner 350 have the same amplitude. Amplifiers 352 and/or 356 are shown in dashed lines because they may not be necessary in some implementations. In one implementation, both amplifier 352 and amplifier 356 are present. In another implementation, neither amplifier 352 nor amplifier 356 is present. In other implementations, one of amplifiers 352, 356 is present, but the other is not.

In the illustrated architecture 300, the signals output by the phase shifters 354 (via amplifiers 352 when present) are combined in the combiner 350. The combiner 350 in architecture 300 combines the RF signals into a signal, as indicated by its presence in block 328. The combiner 350 may be a passive combiner, e.g. not connected to a power supply, which may result in some insertion loss. The combiner 350 may be an active combiner, e.g., connected to a power supply, which may result in a certain signal gain. When combiner 350 is an active combiner, it may provide a different (e.g., configurable) amount of gain for each input signal so that the input signals have the same amplitude when the input signals are combined. When combiner 350 is an active combiner, it may not require second amplifier 352 because the active combiner may provide signal amplification.

The output of the combiner 350 is input to mixers 348 and 346. Mixers 348 and 346 typically down-convert the received RF signal using inputs from local oscillators 372 and 370, respectively, to create an intermediate or baseband signal that carries the encoded and modulated information. The outputs of the mixers 348 and 346 are input into an analog-to-digital converter (ADC)344 for conversion to an analog signal. The analog signal output from ADC 344 is input to modem 302 for baseband processing (e.g., decoding, deinterleaving, etc.).

Architecture 300 is presented merely to illustrate an architecture for transmitting and/or receiving signals. It should be understood that the architecture 300 and/or each portion of the architecture 300 may be repeated multiple times within the architecture to accommodate or provide any number of RF chains, antenna elements, and/or antenna panels. Further, many alternative architectures are possible and contemplated. For example, although only a single antenna array 318 is shown, two, three, or more antenna arrays may be included, each antenna array having one or more of its own corresponding amplifiers, phase shifters, splitters, mixers, DACs, ADCs, and/or modems. For example, a single UE may include two, four, or more antenna arrays for transmitting or receiving signals at different physical locations or in different directions on the UE. Further, mixers, splitters, amplifiers, phase shifters, and other components may be located in different signal type regions (e.g., different regions in blocks 322, 324, 326, 328) in different architectures implemented. For example, in different examples, a signal to be transmitted may be split into multiple signals at analog RF, analog IF, analog baseband, or digital baseband frequencies. Similarly, amplification and/or phase shifting may also be performed at different frequencies. For example, in some contemplated implementations, one or more of the splitter 310, amplifiers 312, 316, or phase shifter 314 may be located between the DAC 304 and the first mixer 306 or between the first mixer 306 and the second mixer 308. In one example, the functionality of one or more components may be combined into one component. For example, the phase shifter 314 may perform amplification to include or replace the first and/or second amplifiers 312, 316. As another example, phase shifting may be implemented by the second mixer 308 to avoid the need for a separate phase shifter 314. This technique is sometimes referred to as Local Oscillator (LO) phase shifting. In one implementation of this configuration, there may be multiple IF-to-RF mixers (e.g., for each antenna element chain) within second mixer 308, and local oscillator B332 will provide a different local oscillator signal (with a different phase offset) to each IF-to-RF mixer.

Modem 302 and/or beam management component 334 may control 472 one or more other components 304 to select one or more antenna elements 320 and/or to form a beam for transmitting one or more signals. For example, the antenna elements 320 may be individually selected or deselected to transmit a signal (or signals) by controlling the amplitude of one or more corresponding amplifiers, such as the first amplifier 312 and/or the second amplifier 316. Beamforming includes generating a beam using multiple signals on different antenna elements, where one or more or all of the multiple signals are phase shifted from each other. The formed beams may carry physical layer or higher layer reference signals or information. As each of the plurality of signals is radiated from a respective antenna element 320, the radiated signals interact, interfere (constructive and destructive interference) and amplify to form a resulting beam. The shape (e.g., amplitude, width, and/or presence of side lobes) and direction (e.g., angle of the beam relative to the surface of the antenna array 318) may be dynamically controlled by modifying the phase shift or phase offset applied by the phase shifter 314 and the amplitude applied by the amplifiers 312, 316 relative to each other for the multiple signals. Beam management component 334 may reside partially or completely within one or more other components of architecture 300. For example, in at least one implementation, beam management component 334 may be located within modem 302.

As described above, fig. 3 is provided as an example. Other examples may differ from the example described with respect to fig. 3.

The 3GPP specifies the use of millimeter waves (mmW) as a carrier for fifth generation (5G) -New Radio (NR) systems. 5G-NR mmW is a time divisionDuplex system (TDD) and uses mmW for both uplink and downlink. The 5G-NR communication system is designed to maintain coverage with low power consumption. In the context of 5G-NR mmW, far-field radiation characteristics of the antenna module and placement of the antenna module in the UE are considered in the context of maintaining coverage with low power consumption. Some regulatory agencies set limits on millimeter wave Power Density (PD) exposure to human safety. It is desirable for the device to prevent PD exposure from exceeding limits when performing mmW related operations. PD exposure may be in milliwatts per square centimeter (mW/cm)²) And (4) showing. For maximum allowed exposure (MPE) limits, PD exposure may be defined for a frequency range and/or an electric field strength. In some cases, guidelines for MPE are based on power density (unit: mW/cm)²) Electric field intensity (unit: volts/meter or V/m) and magnetic field strength (unit: ampere/meter or a/m).

The NR frequency range 2(FR-2), sometimes referred to as mmwave, supports multi-layer transmission (e.g., multi-beam transmission from the UE). Different layers are mapped to different transmit ports corresponding to different antennas. The antennas may be dual polarized (e.g., supporting polarized multiple-input multiple-output (MIMO)) or independent (e.g., supporting spatial MIMO). As used herein, the term layer may refer to a MIMO layer. Different layers may be precoded differently. Different layers (e.g., before precoding) may correspond to different data streams (e.g., after precoding). In some aspects, different layers are used to transmit different codewords. In some other aspects, additionally and/or alternatively, different layers are used to transmit the same codeword.

Various factors, including relative phase shifts between different ports, antennas, layers, etc., may affect the PD associated with the UE. For example, the relative phase and amplitude of the transmissions affect the radiation from the source, which affects the power density of the transmissions. In 3GPP, there is no specific requirement for the absolute value of the relative phase shift between different antenna ports, and the UE may not know the relative phase shift. Furthermore, in case the UE does not know the relative phase shift, the UE has to assume a worst case scenario for PD exposure. The worst case assumption scenario limits the uplink transmit power of the UE to an uplink transmit power compatible with the worst case scenario.

The techniques discussed herein support and provide for communication that handles PD management methods differently than worst case scenario scenarios. Some techniques and apparatus described herein provide a UE that is capable of determining a relative phase difference between multiple beams (e.g., two beams) to be transmitted from the UE. The phase difference determination may be based, for example, at least in part on the particular transmit beam included in the transmit beams, the transmit power level to be used for the transmit beams, and/or one or more other factors described herein. In a particular example, two beams may be used. For example, the UE may determine a relative phase difference between the two beams such that a PD exposure associated with the transmission of the two beams satisfies a threshold. In this way, the UE may reduce or eliminate excessive PD exposure to a user of the UE without having to assume a worst case scenario for PD exposure. This reduces or eliminates limitations on uplink transmit power that would otherwise occur due to having to assume a worst case scenario for PD exposure, thereby improving operation of the UE, improving communication between the UE and the wireless communication device, and so forth.

For sub-6GHz communications (sometimes referred to as frequency range 1 or FR1), single layer communications, or non-orthogonally polarized communications, "digital" beamforming may be performed with a single antenna port. In this approach, the UE may reduce the electromagnetic exposure to the user by modifying the information to be transmitted (e.g., by applying a codeword to the information transmitted using multiple antennas, where the codeword reduces the effective code rate, and where the codeword may be determined experimentally and the resulting electromagnetic exposure may be measured), or modifying the direction of the transmit beam (which may reduce the electromagnetic exposure directed toward the user). When using codewords to modify information, depending on the effective code rate of the codebook from which the codeword is selected, this may result in a loss of information capacity (e.g., a lower code rate) (e.g., only some modulation symbols may be used depending on the electromagnetic exposure resulting from different modulation symbols). This may result in a sub-optimal transmit beam when changing the direction of the transmit beam (e.g., having less favorable beam parameters, e.g., RSRP, RSSI, etc., than the transmit beam used when not changing direction).

For millimeter wave communications (sometimes referred to as frequency range 2 or FR2), multi-layer communications, or orthogonally polarized communications, beamforming may be applied independently to each antenna port and each data stream, unlike the digital beamforming scenarios described above. As described in more detail herein, by modifying the phase difference between two independent beams, electromagnetic exposure (e.g., PD exposure) may be reduced in a near-field region near and/or around the UE (e.g., by reducing near-field combining between transmissions at the user). This approach is transparent to the receiver because applying and/or modifying the phase difference to the two independent beams appears to the receiver as the channel phase. Applying phase differences between beams enables the use of phase differences as an indication of signal characterization. The channel phase may be compensated by the receiver (e.g., without information about the phase applied at the transmitter), unlike the method for non-orthogonally polarized communication described above. This approach does not require signaling between the transmitter and the receiver, since the receiver does not require any display information of the phase applied at the transmitter. Because the receiver and transmitter do not need to signal phase information to each other, each device can save power, and reduced signaling can save network resources and improve throughput. This approach may also save memory resources of the receiver that would otherwise be used to store information about the phase applied at the transmitter.

Further, in some millimeter wave communications, information on different layers may be transmitted on different beams using different (e.g., orthogonal) polarizations. By adjusting the phase difference between the two layers or data streams on the two transmit beams, there is no effect on the beam direction, since each layer or data stream is orthogonally polarized and associated with independent beamforming. Thus, and unlike the method for a non-orthogonally polarized communication system as described above, an optimal beam can be selected and the modification of the phase difference does not affect the beam direction, which may result in transmission on a sub-optimal beam.

Fig. 4 is a diagram illustrating an example 400 relating to power density exposure control in accordance with various aspects of the present disclosure. As shown in fig. 4, example 400 includes a UE (e.g., UE 120) and a wireless communication device (e.g., BS 110, another UE120, etc.).

As indicated by reference numeral 410, the UE may determine a phase difference (e.g., a relative phase difference) to be applied to two transmit beams (e.g., a first transmit beam and a second transmit beam) of the UE based at least in part on a particular transmit beam (e.g., a transmit beam pair) included in the two transmit beams, or a transmit power level to be used for the two transmit beams. For example, the UE may determine a relative phase difference based at least in part on determining to transmit using two beams (e.g., a first beam and a second beam). The two transmit beams may be associated with different transmit ports, different antennas, etc. of the UE. In some aspects, the relative phase difference may be based at least in part on a transmit antenna type (e.g., patch or dipole) of the transmit antenna corresponding to the independently transmitted beams (e.g., the two polarized beams described in this example). For example, different types of antennas may have different patterns, orientations, polarizations, and the like. In some aspects, two transmit beams may be directed to the same receiving device, e.g., a base station, another UE, etc. Although some techniques are described herein in connection with two beams, in some aspects, the techniques may be applied to more than two beams.

In some aspects, the UE may select two beams based at least in part on an indication from the base station. For example, the UE may transmit uplink reference signals, e.g., Sounding Reference Signals (SRS), for multiple beams. The base station may measure the uplink reference signals and may indicate two beams to use (e.g., the two beams with the best measurement results relative to the other beams) based at least in part on the measurements. Alternatively, the base station may indicate more than two beams based at least in part on the measurement results, and the UE may select two of the indicated beams. Alternatively, the UE may select two beams based on measuring downlink reference signals from the base station. For example, the UE may measure downlink reference signals, e.g., Synchronization Signal Blocks (SSBs) and/or channel state information reference signals (CSI-RSs), transmitted via multiple beams. The UE may measure the reference signals to determine signal characteristics (e.g., RSRP, RSRQ, RSSI, CQI, etc.), and may identify two receive beams with the best signal characteristics (e.g., relative to the other beams). The UE may select two transmit beams as part of a corresponding beam pair having two receive beams. Alternatively and/or additionally, the base station may indicate two receive beams for use by the UE (e.g., based at least in part on a report sent by the UE to the base station), and the UE may select the two receive beams as part of a corresponding beam pair having the two receive beams.

The relative phase difference may be such that a power density exposure associated with the UE satisfies a threshold. For example, the relative phase difference may minimize a power density exposure associated with the UE during the time period, be below a threshold, and/or the like. The relative phase difference may be a static value (e.g., a value pre-configured, stored, or hard-coded in a memory of the UE) for a particular transmit beam, for a transmit power level, and so on. For example, the relative phase difference may be a static value for a beam pair combination or a combination of a beam pair and a transmit power level corresponding to the beam pair. Using the static value may reduce complexity and processing of the UE, thereby saving UE resources (e.g., memory resources, processing resources, etc.).

The UE may store information identifying the relative phase difference in a memory resource of the UE. For example, the UE may store the information in a data structure in a memory resource of the UE. The relative phase difference may be indexed in memory resources by a particular transmit beam, transmit power level, etc. For example, the relative phase difference may be indexed such that the UE may perform a lookup for the relative phase difference by identifying information of the two transmit beams, the transmit power levels, and so on.

The UE may configure the relative phase difference. For example, the UE may randomly configure the relative phase difference over time. Continuing with the previous example, the UE may randomly configure the relative phase difference over time to achieve gain on the worst case power density exposure. This reduces or eliminates negative effects on UE operation and/or communication that would otherwise occur due to the UE having to assume a worst-case power density exposure.

The relative phase difference may be further based at least in part on detection results of sensors (e.g., thermal sensors, proximity sensors, thermal proximity sensors, etc.) of the UE. For example, the detection result may indicate whether a portion of the user of the UE is within a threshold proximity of the antennas corresponding to the two transmit beams. As such, the relative phase difference may be based at least in part on the exposure area on the UE for the two transmit beams (e.g., the relative phase difference may be based at least in part on the manner in which the UE is held). This optimizes the relative phase difference for use by the UE, thereby improving the determination of the relative phase difference and minimizing excessive power density exposure control.

The UE may apply a relative phase difference to the two transmit beams before transmitting the two transmit beams. For example, the UE may adjust the phases of the signals corresponding to the two transmit beams (e.g., in a baseband modem) to apply a relative phase difference. In this case, the UE may apply the phase difference to information to be transmitted on one or more layers (e.g., information of the first layer and/or information of the second layer) or to data streams mapped to antenna ports before transmission. By adjusting the phase difference between layers (where information on each layer is transmitted using a different transmit beam and information on each layer may be different) or between data streams, there is no effect on the beam direction because each layer or data stream is orthogonally polarized and is associated with independent beamforming. Thus, the UE may select an optimal transmit beam (e.g., based at least in part on reference signal measurements), and may maintain this selection while reducing electromagnetic exposure by applying phase differences to the layers after selecting the transmit beam.

Additionally or alternatively, as another example, the UE may apply a relative phase difference to the two transmit beams on time domain signal paths corresponding to the two transmit beams (e.g., in a transceiver of the UE). In some aspects, applying a phase difference to two independent transmit beams appears to the receiver as a channel phase, which can be compensated by the receiver without information about the phase applied at the transmitter. This approach does not require signaling since the receiver does not need any explicit information with the phase applied at the transmitter, which saves network resources. This also saves memory resources of the receiver that would otherwise be used to store information about the phase applied at the transmitter.

The UE may configure one or more Radio Frequency (RF) components associated with the transceiver of the UE to apply a relative phase difference to the two transmit beams. For example, the UE may configure one or more RF components based at least in part on codebook entries for two transmit beams (e.g., the relative phase difference may be based at least in part on a relative phase difference between codewords from the codebook entries corresponding to the two transmit beams). Additionally or alternatively, as another example, the UE may configure one or more RF components based at least in part on adding a relative phase difference to phase shifters corresponding to two transmit beams. This facilitates the use of static codebook entries with dynamic relative phase differences based at least in part on dynamic parameters such as detection results, transmit power levels, etc.

As indicated by reference numeral 420, after determining the relative phase difference, the UE may transmit to the wireless communication device simultaneously using two transmit beams. For example, before the UE transmits two transmission beams, a relative phase difference may be applied to the two transmission beams in the manner described above.

As indicated above, fig. 4 is provided as an example. Other examples may differ from the example described with respect to fig. 4.

Fig. 5 is a diagram illustrating an example 500 relating to power density exposure control in accordance with various aspects of the present disclosure. As shown in fig. 5, example 500 includes a UE (e.g., UE 120). As indicated by reference numeral 510, the UE may include a dual-polarized patch array (e.g., a transmit antenna array). For example, the UE may use a dual-polarized patch array to transmit two transmit beams, where the two transmit beams are configured with relative phase differences in a manner similar to that described elsewhere herein. Reference numerals 520-1 and 520-2 show example transmit beams that the UE may transmit.

As indicated above, fig. 5 is provided as an example. Other examples may differ from the example described with respect to fig. 5.

Fig. 6 is a diagram illustrating an example 600 relating to power density exposure control in accordance with various aspects of the present disclosure. As shown in fig. 6, example 600 includes a UE (e.g., UE 120).

As indicated by reference numeral 610, a beam management component of the UE (e.g., beam management component 334) may configure a beam pair (e.g., two transmit beams) for transmitting from the UE. As indicated by reference numeral 620, the configuration of the beam pairs may include selecting a particular transmit beam from a plurality of possible transmit beams. For example, for a selected beam pair corresponding to a pair of beam indices, the UE may apply phase shifter settings to a set of phase shifters 630 (e.g., the set of Tx phase shifters 314 described above in connection with fig. 3) to configure transmission using the selected beam pair. In some aspects, the UE may determine the phase shifter settings for the beam index (corresponding to the beam) using a table stored in the memory of the UE, as shown. In some aspects, the phase shifter settings may include settings for a plurality of phase shifters (e.g., phase shifter 314), shown as P11, P12, P13, and P14, as an example of four phase shifter settings for four phase shifters P11, P12, P13, and P14 for a first antenna port and/or a first beam, and shown as P21, P22, P23, and P24, as an example of four phase shifter settings for four phase shifters P21, P22, P35 23, and P24 (e.g., shown as phase shifter group 630) for a second antenna port and/or a second beam. As described above in connection with fig. 3, the settings of each phase shifter may be independent and separately configurable to provide a desired amount of phase shift and/or phase offset between antenna elements used for transmission via a beam, depending on the phase shifter settings.

As indicated by reference numeral 640, based at least in part on the beam pairs, the UE may determine relative phase differences for the beam pairs in a manner similar to that described elsewhere herein. For example, for a selected beam pair, the UE may apply relative phase differences to configure transmissions via the selected beam pair. In some aspects, the UE may use a table stored in the memory of the UE to determine the relative phase difference for the beam pairs, as shown. As indicated by reference numeral 650, the relative phase difference may additionally be based at least in part on one or more other factors, such as the power level to be used for the beam pair, the detector output (e.g., detection result), and so forth, in a manner similar to that described elsewhere herein. In some aspects, the UE may look up the relative phase difference in a table based at least in part on the selected beam pair, power level, detector output, and/or the like.

As indicated by reference numeral 660, the beam management component or another component of the UE may apply relative phase differences to one or more transmit beams of a beam pair in a manner similar to that described elsewhere herein (e.g., in a manner such that a Power Density (PD) satisfies a threshold). For example, the relative phase difference may be added to the codebook entry for the beam pair. The UE may configure and/or apply additional phase shifter settings to one or more phase shifters in the phase shifter group 630 to achieve a desired phase difference between the beam pairs. In example 600, the UE applies additional phase shifter settings to the set of phase shifters 630 that beamform transmissions for the second antenna port and/or the second beam. In some aspects, the UE may apply additional phase shifter settings to one or more phase shifters used to transmit only one of the beam pairs. Alternatively, the UE may apply additional phase shifter settings to one or more phase shifters used for a first beam of the transmit beam pair and to one or more phase shifters used for a second beam of the transmit beam pair. As indicated by reference numeral 670, the UE may transmit the beam pair via a transmission port corresponding to a transmission beam in the beam pair after applying the relative phase difference.

As indicated above, fig. 6 is provided as an example. Other examples may differ from the example described with respect to fig. 6.

Fig. 7 is a diagram illustrating an example 700 relating to power density exposure control in accordance with various aspects of the present disclosure. As shown in fig. 7, example 700 includes a UE (e.g., UE 120).

Reference numeral 710 shows a dual-polarized patch array similar to that described elsewhere herein. For example, the UE may transmit two transmit beams similar to those described elsewhere herein using a dual-polarized patch array. Reference numeral 720 shows a phaser array associated with the UE. The phase shifter array may apply a relative phase difference to the two transmit beams in a manner similar to that described elsewhere herein. For example, four phase shifters P11, P12, P13, and P14 may receive phase shifter settings to control the relative phase difference between two transmit beams, as described above in connection with fig. 6. The phase shifter array may apply a relative phase difference to a pair of ports (indicated by reference numeral 730) of the UE, for example, by applying a phase shifter setting to the transmission of one or both of the ports. Although fig. 7 shows the Transmit (TX) port and the Receive (RX) port of a shared phase shifter, other configurations are also contemplated in which the phase shifter is not shared between the transmit port and the receive port.

As indicated above, fig. 7 is provided as an example. Other examples may differ from the example described with respect to fig. 7.

Fig. 8 is a diagram illustrating an example process 800 performed, for example, by a UE in accordance with various aspects of the disclosure. The example process 800 is an example in which a UE (e.g., UE120, etc.) performs operations associated with power density exposure control.

As shown in fig. 8, in some aspects, process 800 may include: a relative phase difference to be applied to two transmit beams is determined based at least in part on a particular transmit beam included in the two transmit beams of the UE, or a transmit power level to be used for the two transmit beams (block 810). For example, the UE (e.g., using controller/processor 280, etc.) may determine the relative phase difference to be applied to the two transmit beams based at least in part on the particular transmit beam included in the UE's two transmit beams, or the transmit power levels to be used for the two transmit beams, as described above.

As further shown in fig. 8, in some aspects, process 800 may include: after determining the relative phase difference, the two transmit beams are transmitted to the wireless communication device, where the relative phase difference is applied to the two transmit beams (block 820). For example, as described above, the UE (e.g., using controller/processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, etc.) may transmit the two transmit beams to the wireless communication device after determining the relative phase difference. In some aspects, a relative phase difference is applied to the two transmit beams.

Process 800 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in relation to one or more other processes described elsewhere herein.

In a first aspect, the relative phase difference is such that a power density exposure associated with the UE satisfies a threshold.

In a second aspect, alone or in combination with the first aspect, the relative phase difference is a static value for the particular transmit beam.

In a third aspect, the relative phase difference is a static value for the transmit power level, alone or in combination with one or more of the first and second aspects.

In a fourth aspect, the UE may store information identifying the relative phase difference in a memory resource of the UE, alone or in combination with one or more of the first to third aspects.

In a fifth aspect, alone or in combination with the fourth aspect, the relative phase difference is indexed in memory resources by a particular transmit beam or transmit power level.

In a sixth aspect, the UE may randomly configure the relative phase difference over time, alone or in combination with one or more of the first to fifth aspects.

In a seventh aspect, the relative phase difference is further based at least in part on a detection result of a sensor of the UE, wherein the detection result indicates whether a portion of a user of the UE is within a threshold proximity of antennas corresponding to the two transmit beams, alone or in combination with one or more of the first through sixth aspects. In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, the UE may apply a relative phase difference to the two transmit beams by adjusting the phases of the signals corresponding to the two transmit beams prior to transmitting the two transmit beams.

In a ninth aspect, the UE may apply a relative phase difference to the two transmit beams on time domain signal paths corresponding to the two transmit beams prior to transmitting the two transmit beams, alone or in combination with one or more of the first to eighth aspects.

In a tenth aspect, alone or in combination with one or more of the first to ninth aspects, the UE may apply a relative phase difference to the two transmit beams by configuring one or more RF components associated with a transceiver of the UE prior to transmitting the two transmit beams.

In an eleventh aspect, alone or in combination with the tenth aspect, the UE may configure one or more RF components based at least in part on codebook entries for two transmit beams.

In a twelfth aspect, alone or in combination with the eleventh aspect, the relative phase difference is based at least in part on a relative phase between codewords from the codebook entry corresponding to the two transmit beams.

In a thirteenth aspect, alone or in combination with the tenth aspect, the UE may configure one or more RF components based at least in part on adding a relative phase difference to phase shifters corresponding to two transmit beams.

In a fourteenth aspect, the relative phase difference is across a plurality of ports corresponding to the two transmit beams, alone or in combination with one or more of the first to thirteenth aspects.

In a fifteenth aspect, the relative phase difference is based at least in part on a transmit antenna type of the transmit antennas corresponding to the two transmit beams, alone or in combination with one or more of the first to fourteenth aspects.

Although fig. 8 shows example blocks of the process 800, in some aspects the process 800 may include additional blocks, fewer blocks, different blocks, or a different arrangement of blocks than those shown in fig. 8. Additionally or alternatively, two or more blocks of process 800 may be performed in parallel.

Fig. 9 is a diagram illustrating an example process 900 performed, for example, by a UE in accordance with various aspects of the disclosure. The example process 900 is an example in which a UE (e.g., UE120, etc.) performs operations associated with power density exposure control.

As shown in fig. 9, in some aspects, process 900 may include: two transmit beams are selected from among a plurality of beams that the UE is capable of forming using an antenna array of the UE that includes a plurality of antenna elements, wherein the two transmit beams are to be used for transmitting information of corresponding two layers (block 910). For example, as described above, the UE (e.g., using transmit processor 264, controller/processor 280, memory 282, modem 302, beam management component 324, etc.) may select two transmit beams from among multiple beams that the UE is capable of forming using an antenna array of the UE that includes multiple antenna elements. In some aspects, two transmit beams are to be used for transmitting information of the corresponding two layers.

As further shown in fig. 9, in some aspects, process 900 may include: after selecting the two transmit beams, a phase difference to be applied to the two transmit beams is determined based at least in part on the two transmit beams (block 920). For example, as described above, the UE (e.g., using transmit processor 264, controller/processor 280, memory 282, modem 302, beam management component 324, etc.) may determine a phase difference to be applied to the two transmit beams based at least in part on the two transmit beams after selecting the two transmit beams.

As further shown in fig. 9, in some aspects, process 900 may include: information is simultaneously transmitted on the corresponding two layers via the two transmit beams using the phase difference (block 930). For example, as described above, the UE (e.g., using transmit processor 264, controller/processor 280, memory 282, modem 302, beam management component 324, splitter 310, amplifier 312, Tx phase shifter 314, amplifier 316, antenna array 318, one or more antenna elements 320, etc.) may transmit information simultaneously on the corresponding two layers via the two transmit beams using phase differences.

Process 900 may include additional aspects, such as any single aspect or any combination of aspects described below and/or related to one or more other processes described elsewhere herein.

In the first aspect, the corresponding two layers are transmitted via the two transmit beams using different polarizations on each of the two transmit beams.

In a second aspect, alone or in combination with the first aspect, the phase difference is further determined based at least in part on respective transmit power levels to be used for the two transmit beams.

In a third aspect, the phase difference is a static value for the transmit power level, alone or in combination with one or more of the first and second aspects.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, the phase difference is further determined based at least in part on a detection result of a sensor of the UE, the detection result indicating whether a portion of a user of the UE is within a threshold proximity of an antenna element used to generate the two transmit beams.

In a fifth aspect, the phase difference is such that a power density exposure associated with the UE satisfies a threshold, alone or in combination with one or more of the first to fourth aspects.

In a sixth aspect, the phase difference is a static value for the two transmit beams, alone or in combination with one or more of the first to fifth aspects.

In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, the process 900 includes storing information identifying a phase difference in a memory resource of the UE, and the phase difference is indexed in the memory resource in association with the information identifying the two transmit beams.

In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, determining the phase difference comprises randomly configuring the phase difference over time.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, the process 900 comprises: a phase difference is applied to the two transmit beams by adjusting the phase of the signals corresponding to the two transmit beams before transmitting information on the corresponding two layers.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, the process 900 comprises: a phase difference is applied to the two transmit beams on the time domain signal paths corresponding to the two transmit beams before transmitting information on the corresponding two layers.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, the process 900 comprises: a phase difference is applied to the two transmit beams by configuring one or more Radio Frequency (RF) components associated with a transceiver of the UE prior to transmitting information on the corresponding two layers.

In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, configuring one or more RF components comprises: configuring one or more RF components based at least in part on the codebook entries for the two transmit beams.

In a thirteenth aspect, the phase difference is based at least in part on a relative phase between codewords from the codebook entry corresponding to the two transmit beams, alone or in combination with one or more of the first through twelfth aspects.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, configuring one or more RF components comprises: configuring one or more RF components based at least in part on adding a phase difference to phase shifters corresponding to two transmit beams.

In a fifteenth aspect, the phase difference is across a plurality of ports corresponding to the two transmit beams, alone or in combination with one or more of the first to fourteenth aspects.

In a sixteenth aspect, the phase difference is based at least in part on a transmit antenna type of the transmit antennas corresponding to the two transmit beams, alone or in combination with one or more of the first to fifteenth aspects.

Although fig. 9 shows example blocks of the process 900, in some aspects the process 900 may include additional blocks, fewer blocks, different blocks, or a different arrangement of blocks than those shown in fig. 9. Additionally or alternatively, two or more blocks of process 900 may be performed in parallel.

In addition to the aspects and examples described above, additional embodiments and features are also contemplated. As one example, a method of wireless communication performed by a User Equipment (UE) may generally include applying a phase difference between a first communication beam and a second communication beam. The communication beam may include a transmit beam and a receive beam. The method may also include transmitting information on the first communication beam and the second communication beam. The information transmission may occur simultaneously on the first communication beam and the second communication beam. Additionally and/or alternatively, the communication may occur continuously or in other timing arrangements (e.g., spaced apart timing). The method may also include selecting a first communication beam and a second communication beam. This selection may be accomplished by selecting two transmit beams from a plurality of beams in some approaches. The selection method may be different and may include random selection, desired beams corresponding to the layer of interest, and/or based on performance characteristics/metrics. Beam selection may be performed for beams that the UE is capable of forming using the antenna array. The antenna array may include one or more antenna elements. The selected communication beam may include two transmission beams used to transmit information of the corresponding two layers.

As another example, a user equipment may be configured for beam communication with a phase difference application between communication beams. Such user equipment may include various components including memory, processors, and communication interfaces (e.g., transmitters, receivers, transceivers, modems, Radio Frequency (RF) front end chains, etc.). These components may be configured to cooperatively interact with each other (e.g., the processor may send instructions to one or more other components). The communication interface may apply a phase difference between the first communication beam and the second communication beam. The phase difference may be set to indicate information to the receiver without the UE having to use dedicated signaling. As discussed herein, applying a phase difference to the communication may help limit and/or manage RF radiation/exposure.

The communication beam may be used in various ways in mmWave communication. For example, the communication interface of the UE may also transmit information about the first communication beam and the second communication beam. Additionally and/or alternatively, the communication beam may be used for a receive beam to receive transmitted information. The information transmission may occur simultaneously on the first communication beam and the second communication beam. Additionally and/or alternatively, the communication may occur continuously or in other timing arrangements (e.g., spaced apart timing).

The communication interface of the UE may also include selecting a first communication beam and a second communication beam. Selection may be achieved by selecting two transmit beams from a plurality of beams in some deployments. The selection of beams may vary and include various methods (e.g., round robin, sequential, random, opportunistic considering channel conditions, performance based considering historical operations, etc.). Beam selection may be performed for beams that the UE is capable of forming using the antenna array. The antenna array may include one or more antenna elements. The selected communication beam may include two transmission beams used to transmit information of the corresponding two layers.

As a further example, the user equipment may include the means described herein to perform the functions and actions described in the preceding two paragraphs. The unit may include various structural components, physical arrangements, and details of operation, as illustrated in the several figures and described in the associated text.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit aspects to the precise form disclosed. Modifications and variations are possible in light of the above disclosure or may be acquired from practice of the aspects.

As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software.

Some aspects are described herein in connection with a threshold. As used herein, meeting a threshold may refer to a value that is greater than the threshold, greater than or equal to the threshold, less than or equal to the threshold, not equal to the threshold, and the like.

It will be apparent that the systems and/or methods described herein may be implemented in various forms of hardware, firmware, or combinations of hardware and software. The actual specialized control hardware or software code used to implement the systems and/or methods is not limiting of these aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to the specific software code-it being understood that software and hardware may be designed to implement the systems and/or methods based, at least in part, on the description herein.

Although particular combinations of features are set forth in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of the various aspects. Indeed, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of the various aspects includes each dependent claim in combination with every other claim in the set of claims. A phrase referring to "at least one of" a list of items refers to any combination of those items, including a single member. By way of example, "at least one of a, b, or c" is intended to encompass a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination of multiple identical elements (e.g., a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b-b, b-b-c, c-c, and c-c-c, or any other ordering of a, b, and c).

No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. In addition, as used herein, the articles "a" and "an" are intended to include one or more items, and may be used interchangeably with "one or more". Further, as used herein, the terms "group" and "grouping" are intended to include one or more items (e.g., related items, unrelated items, combinations of related and unrelated items, etc.) and may be used interchangeably with "one or more". Where only one item is desired, the term "only one" or similar language is used. Furthermore, as used herein, the terms "having," "containing," and the like are intended to be open-ended terms. Further, the phrase "based on" is intended to mean "based, at least in part, on" unless explicitly stated otherwise.