Time-averaged radio frequency (RF) exposure by antenna group

Abstract

Some aspects of the present disclosure provide techniques for radio frequency (RF) exposure using antenna grouping. An exemplary method for grouping antennas for RF exposure matching by a processing system generally includes determining an RF exposure distribution for each transmit antenna configuration for a plurality of transmit antennas, and assigning the plurality of transmit antennas to a plurality of antenna groups based on the RF exposure distribution.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 070,268, filed August 26, 2020, U.S. Provisional Application No. 63 / 077,460, filed September 11, 2020, U.S. Provisional Application No. 63 / 170,414, filed April 2, 2021, and U.S. Provisional Application No. 63 / 173,086, filed April 9, 2021, each of which is expressly incorporated by reference in its entirety for all applicable purposes as if fully set forth below. [Background technology]

[0002] Field of Disclosure Aspects of the present disclosure relate to wireless communication, and more particularly, to radio frequency (RF) exposure using antenna groupings. 2. Description of Related Art

[0003] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephone, video, data, messaging, and broadcast. Modern wireless communication devices (such as cellular telephones) are generally required to meet radio frequency (RF) exposure limits set by national and international standards and regulations. To ensure compliance with the standards, such devices currently must undergo an extensive certification process before being released to the market. To ensure that wireless communication devices comply with RF exposure limits, techniques have been developed to enable wireless communication devices to assess RF exposure from the wireless communication device in real time and adjust the transmit power of the wireless communication device accordingly to comply with the RF exposure limits. Summary of the Invention

[0003]

[0004] The systems, methods, and devices of the present disclosure each have several aspects, no single aspect of which is solely responsible for the desirable attributes of the present disclosure. Without limiting the scope of the present disclosure as expressed by the claims that follow, several features will now be briefly described. Considering this description, and particularly reading the section entitled "Detailed Description of the Invention," one will understand how the features of the present disclosure provide advantages, including mutually exclusive antenna groupings and desirable transmit power using antenna groupings.

[0004]

[0005] Some aspects of the subject matter described in this disclosure may be implemented in a method of wireless communication by a user equipment. The method generally includes accessing a stored backoff factor associated with an antenna group of a plurality of antenna groups. The method also includes transmitting a signal from at least one transmit antenna in the antenna group at a transmission power level based on the backoff factor in accordance with RF exposure requirements.

[0005]

[0006] Some aspects of the subject matter described in this disclosure may be implemented by an apparatus. The apparatus generally includes a memory, a processor, and a transmitter. The processor is coupled to the memory, and the processor and the memory are configured to access a stored back-off factor associated with an antenna group of a plurality of antenna groups. The transmitter is configured to transmit a signal from at least one transmit antenna in the antenna group at a transmit power level based on the back-off factor in accordance with an RF exposure requirement.

[0006]

[0007] Certain aspects of the subject matter described in this disclosure may be implemented by an apparatus that generally includes: means for accessing a stored back-off factor associated with an antenna group of a plurality of antenna groups; and means for transmitting a signal from at least one transmit antenna in the antenna group at a transmit power level based on the back-off factor in accordance with an RF exposure requirement.

[0007]

[0008] Some aspects of the subject matter described in this disclosure may be implemented by a computer-readable medium having stored thereon instructions for accessing a stored back-off factor associated with an antenna group of a plurality of antenna groups, and transmitting a signal from at least one transmit antenna in the antenna group at a transmit power level based on the back-off factor in accordance with radio frequency (RF) exposure requirements.

[0008]

[0009] Some aspects of the subject matter described in this disclosure may be implemented in a method for grouping antennas for radio frequency (RF) exposure compliance by a processing system. The method generally includes determining RF exposure distributions for each transmit antenna configuration for a plurality of transmit antennas and assigning the plurality of transmit antennas to a plurality of antenna groups based on the RF exposure distributions.

[0009]

[0010] Certain aspects of the subject matter described in this disclosure may be implemented by an apparatus for grouping antennas of a wireless communication device. The apparatus generally includes a memory and a processor coupled to the memory. The processor and the memory are configured to determine an RF exposure distribution for each transmit antenna configuration for a plurality of transmit antennas of the wireless communication device and assign the plurality of transmit antennas to a plurality of antenna groups based on the RF exposure distribution.

[0010]

[0011] Certain aspects of the subject matter described in this disclosure may be implemented by an apparatus for grouping antennas of a wireless communication device. The apparatus generally includes: means for determining an RF exposure distribution for each transmit antenna configuration for a plurality of transmit antennas; and means for assigning the plurality of transmit antennas to a plurality of antenna groups based on the RF exposure distribution.

[0011]

[0012] Certain aspects of the subject matter described in this disclosure may be implemented by a computer-readable medium having stored thereon instructions for determining an RF exposure distribution for each transmit antenna configuration for multiple transmit antennas of a wireless communication device and assigning the multiple transmit antennas to multiple antenna groups based on the RF exposure distribution.

[0012]

[0013] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of the various aspects may be employed.

[0013]

[0014] So that the above-mentioned features of the present disclosure can be understood in detail, a more particular description briefly summarized above may be had by reference to embodiments, some of which are illustrated in the drawings. However, since the description may lead to other equally valid embodiments, it should be noted that the accompanying drawings illustrate only some typical embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure. [Brief explanation of the drawings]

[0014] [Figure 1]

[0015] FIG. 1 is a block diagram conceptually illustrating an example wireless communication network, in accordance with certain aspects of the present disclosure. [Figure 2]

[0016] 1 is a block diagram conceptually illustrating an example base station (BS) and user equipment (UE) design in accordance with certain aspects of the present disclosure. [Figure 3]

[0017] 1 is a block diagram of an example radio frequency (RF) transceiver in accordance with certain aspects of the present disclosure. [Figure 4]

[0018] 1 illustrates an example of a distribution of normalized specific absorption rate (SAR) combined with a distribution of normalized power density (PD), according to some embodiments of the present disclosure. [Figure 5]

[0019] FIG. 1 illustrates a system for measuring RF exposure distribution, according to some embodiments of the present disclosure. [Figure 6]

[0020] 1 is a flow diagram illustrating example operations for grouping antennas for RF exposure compliance by a UE, in accordance with certain aspects of the present disclosure. [Figure 7]

[0021] FIG. 1 is a block diagram illustrating an example grouping of multiple antennas of a wireless communication device, in accordance with certain aspects of the present disclosure. [Figure 8]

[0022] 10 is a flow diagram illustrating example operations for determining back-off factors for antenna groups in accordance with certain aspects of the present disclosure. [Figure 9]

[0023] 10 is a flow diagram illustrating example operations for assigning antennas to groups based on back-off factors in accordance with certain aspects of the present disclosure. [Figure 10]

[0024] 1 is a flow diagram illustrating example operations for wireless communication by a UE, in accordance with certain aspects of the present disclosure. [Figure 11]

[0025] FIG. 1 illustrates a communications device (e.g., a UE) that may include various components configured to perform operations for the techniques disclosed herein, in accordance with certain aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015]

[0026] For ease of understanding, where possible, the same reference numbers have been used to designate like elements that are common to each of the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

[0016]

[0027] Aspects of the present disclosure provide apparatuses, methods, processing systems, and computer-readable media for adapting radio frequency (RF) exposure based on antenna groups. In some cases, antennas may be grouped using, for example, a back-off factor to determine the antenna grouping. In aspects, antenna groups may be defined and / or operated to be mutually exclusive in terms of RF exposure. That is, RF exposure compliance and corresponding transmit power levels may be determined separately for each antenna group. Aspects of the present disclosure provide various techniques for determining time-averaged RF exposure compliance for each transmit antenna group. Because the antenna groupings described herein may provide mutually exclusive antenna groups, RF exposure compliance for each antenna group may be determined separately. In some cases, RF exposure compliance determinations for multiple antenna groups may be performed in parallel (e.g., simultaneously). The group-based RF exposure adaptation described herein may enable desirable transmit power for a particular antenna group due to, for example, different exposure scenarios encountered by each antenna group. The desired transmit power may provide desired uplink performance, such as a desired uplink data rate, uplink carrier aggregation, and / or uplink connectivity at the edge of the cell.

[0017]

[0028] The following description provides examples of RF exposure adaptation in a communication system and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of the elements discussed without departing from the scope of the present disclosure. Various examples may omit, substitute, or add various procedures or components, as appropriate. For example, described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of aspects described herein. Furthermore, the scope of the present disclosure is intended to cover such apparatuses or methods implemented using other structure, functions, or structure and functions in addition to or other than the various aspects of the disclosure described herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

[0018]

[0029] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (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, subcarrier, frequency channel, tone, subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs.

[0019]

[0030] The techniques described herein may be used for various wireless networks and radio technologies. Although aspects may be described herein using terminology commonly associated with 3G, 4G, and / or new radio (e.g., 5G NR) wireless technologies, aspects of the present disclosure may be applied in other generation-based communication systems.

[0020]

[0031] NR access may support various wireless communication services, such as enhanced mobile broadband (eMBB), which targets wide bandwidths (e.g., 80 MHz or greater); millimeter wave (mmWave), which targets high carrier frequencies (e.g., 24 GHz to 53 GHz or greater); massive machine-type communications (MTC), which targets non-backward compatible MTC techniques; and / or mission-critical, which targets ultra-reliable low-latency communications (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet their respective quality of service (QoS) requirements. Furthermore, these services may coexist in the same subframe. NR supports beamforming, and beam directions may be dynamically configured. Multiple-input multiple-output (MIMO) transmission with precoding is supported, and multi-layer transmission may also be supported. Aggregation of multiple cells may be supported.

[0021] Exemplary Wireless Communication Networks and Devices

[0032] 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be implemented. For example, the wireless communication network 100 may be an NR system (e.g., a 5G NR network), an Evolved Universal Terrestrial Radio Access (E-UTRA) system (e.g., a 4G network), a Universal Mobile Telecommunications System (UMTS) (e.g., a 2G / 3G network), or a Code Division Multiple Access (CDMA) system (e.g., a 2G / 3G network), or may be configured for communication according to an IEEE standard, such as one or more of the 802.11 standard, etc. As shown in FIG. 1, the UE 120a includes an RF exposure manager 122 that enforces RF composure compliance for each of the mutually exclusive antenna groups in accordance with aspects of the present disclosure.

[0022]

[0033] As shown in FIG. 1, wireless communication network 100 may include several BSs 110a-z (each also referred to herein individually as BS 110 or collectively as BS 110) and other network entities. BSs 110 may provide communication coverage for a particular geographic area, sometimes referred to as a “cell,” which may be fixed or may move according to the location of mobile BSs 110. In some examples, BSs 110 may be interconnected to one another and / or to one or more other BSs or network nodes (not shown) in wireless communication network 100 through various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.) using any suitable transport network. In the example shown in FIG. 1, BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more cells.

[0023]

[0034] The BS 110 communicates with UEs 120a-y (each referred to individually as a UE 120 or collectively as UEs 120 herein) in the wireless communication network 100. The UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE 120 may be stationary or mobile. The wireless communication network 100 may also include relay stations (e.g., relay station 110r), also referred to as relays, that receive transmissions of data and / or other information from upstream stations (e.g., the BS 110a or the UE 120r) and send transmissions of data and / or other information to downstream stations (e.g., the UE 120 or the BS 110) or relay transmissions between the UEs 120 to facilitate communication between the devices.

[0024]

[0035] The network controller 130 may be in communication with the set of BSs 110 and may provide coordination and control for these BSs 110 (e.g., via a backhaul). In some cases, the network controller 130 may include a centralized unit (CU) and / or a distributed unit (DU), for example, in a 5G NR system. In an aspect, the network controller 130 may be in communication with a core network 132 (e.g., a 5G core network (5GC)), which provides various network functions such as access and mobility management, session management, user plane functions, policy control functions, authentication server functions, integrated data management, application functions, network exposure functions, network repository functions, and network slice selection functions.

[0025]

[0036] FIG. 2 illustrates example components of a BS 110a and a UE 120a (eg, wireless communication network 100 of FIG. 1) that may be used to implement aspects of the present disclosure.

[0026]

[0037] At the BS 110a, the transmit processor 220 may receive data from the data source 212 and control information from the controller / processor 240. The control information may be for a Physical Broadcast Channel (PBCH), a Physical Control Format Indicator Channel (PCFICH), a Physical Hybrid ARQ Indicator Channel (PHICH), a Physical Downlink Control Channel (PDCCH), a Group Common PDCCH (GC PDCCH), etc. The data may be for a Physical Downlink Shared Channel (PDSCH), etc. A Medium Access Control (MAC)-Control Element (MAC-CE) is a MAC layer communication structure that may be used for control command exchange between wireless nodes. The MAC-CE may be carried in a shared channel such as the PDSCH, the Physical Uplink Shared Channel (PUSCH), or the Physical Sidelink Shared Channel (PSSCH).

[0027]

[0038] The processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH demodulation reference signal (DMRS), and a channel state information reference signal (CSI-RS). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​the data symbols, control symbols, and / or reference symbols, if applicable, and provide output symbol streams to modulators (MODs) 232a through 232t in the transceiver. Each modulator 232a through 232t in the transceiver may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 232a through 232t in the transceivers may be transmitted via antennas 234a through 234t, respectively.

[0028]

[0039] At UE 120a, antennas 252a through 252r may receive downlink signals from BS 110a and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively, in the transceiver. Each demodulator 254a through 254r in the transceiver may condition (e.g., filter, amplify, downconvert, and digitize) its respective received signal to obtain input samples. Each demodulator 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 demodulators 254a through 254r in the transceiver, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols and provide decoded data for UE 120a to a data sink 260 and decoded control information to controller / processor 280.

[0029]

[0040] On the uplink, at UE 120a, a transmit processor 264 may receive and process data from a data source 262 (e.g., for the Physical Uplink Shared Channel (PUSCH)) and control information from a controller / processor 280 (e.g., for the Physical Uplink Control Channel (PUCCH)). The transmit processor 264 may also generate reference symbols for a reference signal (e.g., for a Sounding Reference Signal (SRS)). The symbols from transmit processor 264 are transmitted to a TX The uplink signal from the UE 120a may be precoded by a MIMO processor 266, further processed by modulators (MODs) 254a-254r in the transceiver (e.g., for SC-FDM, etc.), and transmitted to the BS 110a. At the BS 110a, the uplink signal from the UE 120a may be received by the antennas 234, processed by modulators 232a-232t in the transceiver, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by the UE 120a. The receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to a controller / processor 240.

[0030]

[0041] Memories 242 and 282 may store data and program codes for BS 110a and UE 120a, respectively. Scheduler 244 may schedule UEs for data transmission on the downlink and / or uplink.

[0031]

[0042] The antennas 252, processors 266, 258, 264, and / or controller / processor 280 of the UE 120a and / or the antennas 234, processors 220, 230, 238, and / or controller / processor 240 of the BS 110a may be used to implement various techniques and methods described herein. As shown in FIG. 2, the controller / processor 280 of the UE 120a has an RF exposure manager 281 that enforces RF serenity adaptation for each antenna group of mutually exclusive antenna groups in accordance with aspects described herein. While shown as a controller / processor, other components of the UE 120a and the BS 110a may be used to implement the operations described herein.

[0032]

[0043] NR may utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and downlink. NR may support half-duplex operation using time division duplexing (TDD). OFDM and single-carrier frequency division multiplexing (SC-FDM) partition the system bandwidth into multiple orthogonal subcarriers, also commonly referred to as tones, bins, etc., where each subcarrier may be modulated with data. Modulation symbols may be sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers may depend on the system bandwidth. The system bandwidth may also be partitioned into subbands. For example, a subband may cover multiple resource blocks (RBs).

[0033]

[0044] 1 and 2 as communicating with a BS and / or within a network, the UE 120a may be configured to communicate / transmit directly to another UE 120 or another wireless device without relaying the communication through a network. In some embodiments, the BS 110a shown in FIG. 2 and described above is an example of another UE 120.

[0034] Exemplary RF Transceiver

[0045] 3 is a block diagram of an example RF transceiver circuit 300 according to some aspects of the present disclosure. The RF transceiver circuit 300 includes at least one transmit (TX) path 302 (also known as a transmit chain) for transmitting signals via one or more antennas 306 and at least one receive (RX) path 304 (also known as a receive chain) for receiving signals via the antenna 306. When the TX path 302 and the RX path 304 share the antenna 306, the paths may be connected to the antenna via an interface 308, which may include any of a variety of suitable RF devices, such as a switch, a duplexer, a diplexer, a multiplexer, etc.

[0035]

[0046] When receiving an in-phase (I) or quadrature (Q) baseband analog signal from a digital-to-analog converter (DAC) 310, the TX path 302 may include a baseband filter (BBF) 312, a mixer 314, a driver amplifier (DA) 316, and a power amplifier (PA) 318. The BBF 312, mixer 314, and DA 316 may be included in one or more radio frequency integrated circuits (RFICs). The PA 318 may be external to the RFIC in some implementations.

[0036]

[0047] The BBF 312 filters the baseband signal received from the DAC 310, and the mixer 314 mixes the filtered baseband signal with a transmit local oscillator (LO) signal to convert the baseband signal of interest to a different frequency (e.g., upconvert from baseband to radio frequency). This frequency conversion process generates sum and difference frequencies between the LO frequency and the frequency of the baseband signal of interest. The sum and difference frequencies are called beat frequencies. The beat frequencies are generally in the RF range; therefore, the signal output by the mixer 314 is generally an RF signal, which may be amplified by the DA 316 and / or the PA 318 before transmission by the antenna 306. Although one mixer 314 is shown, several mixers may be used to upconvert the filtered baseband signal to one or more intermediate frequencies and then upconvert the intermediate frequency signal to a frequency for transmission.

[0037]

[0048] The RX path 304 may include a low noise amplifier (LNA) 324, a mixer 326, and a baseband filter (BBF) 328. The LNA 324, mixer 326, and BBF 328 may be included in one or more RFICs, which may or may not be the same RFIC containing the TX path components. An RF signal received via the antenna 306 may be amplified by the LNA 324, and the mixer 326 mixes the amplified RF signal with a receive local oscillator (LO) signal to convert (e.g., downconvert) the RF signal of interest to a different baseband frequency. The baseband signal output by the mixer 326 may be filtered by the BBF 328 before being converted by an analog-to-digital converter (ADC) 330 to a digital I or Q signal for digital signal processing.

[0038]

[0049] Some transceivers may employ a frequency synthesizer with a voltage-controlled oscillator (VCO) to generate a stable, tunable LO with a specific tuning range. Thus, the transmit LO may be generated by the TX frequency synthesizer 320, which may be buffered or amplified by an amplifier 322 before being mixed with the baseband signal in the mixer 314. Similarly, the receive LO may be generated by the RX frequency synthesizer 332, which may be buffered or amplified by an amplifier 334 before being mixed with the RF signal in the mixer 326.

[0039]

[0050] The controller 336 may direct the operation of the RF transceiver circuit 300, such as transmitting signals via the TX path 302 and / or receiving signals via the RX path 304. The controller 336 may be a processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof. The memory 338 may store data and program code for operating the RF transceiver circuit 300. The controller 336 and / or the memory 338 may include control logic. In some cases, the controller 336 may determine a time-averaged RF exposure measurement based on a transmit power level applied to the TX path 302 (e.g., some level of gain in the PA 318) to set a transmit power level that complies with RF exposure limits set by national regulations and international standards, as further described herein.

[0040] Exemplary RF Exposure Distribution

[0051] RF exposure can be expressed in terms of the specific absorption rate (SAR), which measures the energy absorption by human tissue per unit mass and has units of watts per kilogram (W / kg). RF exposure can also be expressed in terms of power density (PD), which measures the energy absorption per unit area and has units of mW / cm.2 In some cases, maximum permissible exposure (MPE) limits for PDs may be imposed for wireless communication devices using transmission frequencies above 6 GHz. MPE limits are defined as a regulatory metric for area-based exposure to prevent incidents of human exposure represented by tissue temperature changes, e.g., a number, X, of watts per square meter (W / m ) averaged over a defined area and time-averaged over a frequency-dependent time window. 2 ) is the energy density limit defined as

[0041]

[0052] SAR may be used to assess RF exposure for transmission frequencies lower than 6 GHz, which covers wireless communication technologies such as 2G / 3G (e.g., CDMA), 4G (e.g., LTE), 5G (e.g., NR in the 6 GHz band), IEEE 802.11ac, etc. PD may be used to assess RF exposure for transmission frequencies higher than 6 GHz, which covers wireless communication technologies such as IEEE 802.11ad, 802.11ay, 5G in the mmWave band, etc. Therefore, different metrics may be used to assess RF exposure for different wireless communication technologies.

[0042]

[0053] A wireless communication device (e.g., UE 120) may simultaneously transmit signals using multiple wireless communication technologies. For example, a wireless communication device may simultaneously transmit signals using a first wireless communication technology operating at or below 6 GHz (e.g., 3G, 4G, 5G, etc.) and a second wireless communication technology operating above 6 GHz (e.g., mmWave 5G, IEEE 802.11ad, or 802.11ay in the 24 to 60 GHz band). In some aspects, a wireless communication device may simultaneously transmit signals using a first wireless communication technology (e.g., 3G, 4G, 5G in the sub-6 GHz band, IEEE 802.11ac, etc.) for which RF exposure is measured in terms of SAR and a second wireless communication technology (e.g., 5G, IEEE 802.11ad, 802.11ay, etc.) for which RF exposure is measured in terms of PD. As used herein, the sub-6 GHz band may include a frequency band from 300 MHz to 6,000 MHz.

[0043]

[0054] To assess RF exposure from transmissions using a first technology (e.g., 3G, 4G, 5G in sub-6 GHz bands, IEEE 802.11ac, etc.), a wireless communication device may include multiple SAR distributions for the first technology stored in memory (e.g., memory 282 of FIG. 2 or memory 338 of FIG. 3). Each of the SAR distributions may correspond to each of multiple transmission scenarios supported by the wireless communication device for the first technology. The transmission scenarios may correspond to various combinations of antennas (e.g., antennas 252a through 252r of FIG. 2 or antenna 306 of FIG. 3), frequency bands, channels, and / or body positions, as described further below.

[0044]

[0055] A SAR distribution (also referred to as a SAR map) for each transmit scenario may be generated based on measurements (e.g., electric field measurements) performed in a test laboratory using a human body model. After the SAR distribution is generated, it is stored in memory to enable a processor (e.g., processor 280 of FIG. 2 or controller 336 of FIG. 3) to assess RF exposure in real time, as described further below. Each SAR distribution includes a set of SAR values, where each SAR value may correspond to a different location (e.g., on the human body model). Each SAR value may comprise a SAR value averaged over a mass of 1 g or 10 g at the respective location.

[0045]

[0056] The SAR values ​​in each SAR distribution correspond to a particular transmit power level (e.g., the transmit power level at which the SAR values ​​were measured in a test laboratory). Because the SAR scales with the transmit power level, the processor may scale the SAR distribution for any transmit power level by multiplying each SAR value in the SAR distribution by a transmit power scaler:

[0046]

number

[0047] where Tx c is the current transmit power level for each transmission scenario, and Tx SAR is the transmit power level corresponding to the SAR value in the stored SAR distribution (for example, the transmit power level at which the SAR value is measured in a testing laboratory).

[0048]

[0057] As described above, a wireless communication device may support multiple transmission scenarios for a first technology. In some aspects, a transmission scenario may be specified by a set of parameters. The set of parameters may include one or more of: an antenna parameter indicating one or more antennas used for transmission (i.e., active antennas); a frequency band parameter indicating one or more frequency bands used for transmission (i.e., active frequency bands); a channel parameter indicating one or more channels used for transmission (i.e., active channels); a body posture parameter indicating the location of the wireless communication device relative to a user's body location (head, trunk, away from the body, etc.); and / or other parameters. When a wireless communication device supports a large number of transmission scenarios, performing measurements for each transmission scenario in a test setting (e.g., a test laboratory) may be very time-consuming and expensive. To reduce test time, measurements may be performed on a subset of the transmission scenarios to generate an SAR distribution for the subset of transmission scenarios. In this example, the SAR distribution for each of the remaining transmission scenarios may be generated by combining two or more of the SAR distributions for the subset of transmission scenarios, as described further below.

[0049]

[0058] For example, SAR measurements may be performed on each of the antennas to generate a SAR distribution for each of the antennas. In this example, a SAR distribution for a transmission scenario in which two or more of the antennas are active may be generated by combining the SAR distributions for the two or more active antennas.

[0050]

[0059] In another example, SAR measurements may be performed for each of a plurality of frequency bands to generate a SAR distribution for each of the plurality of frequency bands. In this example, a SAR distribution for a transmission scenario in which two or more frequency bands are active may be generated by combining the SAR distributions for the two or more active frequency bands.

[0051]

[0060] In some aspects, the SAR distribution may be normalized with respect to the SAR limit by dividing each SAR value in the SAR distribution by the SAR limit, where the normalized SAR value exceeds the SAR limit when the normalized SAR value is greater than 1 and is below the SAR limit when the normalized SAR value is less than 1. In these aspects, each of the SAR distributions stored in memory may be normalized with respect to the SAR limit.

[0052]

[0061] In some aspects, a normalized SAR distribution for a transmission scenario may be generated by combining two or more normalized SAR distributions. For example, a normalized SAR distribution for a transmission scenario in which two or more antennas are active may be generated by combining the normalized SAR distributions for two or more active antennas. If different transmit power levels are used for the active antennas, the normalized SAR distribution for each active antenna may be scaled by its respective transmit power level before combining the normalized SAR distributions for the active antennas. The normalized SAR distribution for simultaneous transmission from multiple active antennas may be given by:

[0053]

number

[0054] Here, SAR lim is the SAR limit, and SAR norm_combined is the combined normalized SAR distribution for simultaneous transmission from the active antennas, i is the index for the active antenna, and SAR i is the SAR distribution for the i-th active antenna, and Tx i is the transmit power level for the i-th active antenna, and Tx SARi is the transmit power level for the SAR distribution for the i-th active antenna, and K is the number of active antennas.

[0055]

[0062] Equation (2) can be rewritten as follows:

[0056]

number

[0057] Here, SAR norm_i is the normalized SAR distribution for the i-th active antenna. In the case of simultaneous transmission using multiple active antennas at the same transmission frequency (e.g., multiple-input multiple-output (MIMO)), the combined normalized SAR distribution may be obtained by adding the square roots of the individual normalized SAR distributions and calculating the square of the sum, as given by:

[0058]

number

[0059]

[0063] In another example, normalized SAR distributions for different frequency bands may be stored in memory. In this example, a normalized SAR distribution for a transmission scenario in which two or more frequency bands are active may be generated by combining the normalized SAR distributions for the two or more active frequency bands. If the transmit power levels for the active frequency bands are different, the normalized SAR distribution for each of the active frequency bands may be scaled by the respective transmit power levels before combining the normalized SAR distributions for the active frequency bands. In this example, the combined SAR distribution may also be calculated using Equation (3a), where i is an index for the active frequency band and SAR norm_i is the normalized SAR distribution for the i-th active frequency band, and Tx i is the transmit power level for the i-th active frequency band, and Tx SARi is the transmit power level for the normalized SAR distribution for the i-th active frequency band.

[0060]

[0064] To assess RF exposure from transmissions using a second technology (e.g., 5G in the 24 to 60 GHz band, IEEE 802.11ad, 802.11ay, etc.), the wireless communication device may include multiple PD distributions for the second technology stored in memory (e.g., memory 282 of FIG. 2 or memory 338 of FIG. 3). Each of the PD distributions may correspond to each of multiple transmission scenarios supported by the wireless communication device for the second technology. The transmission scenarios may correspond to various combinations of antennas (e.g., antennas 252a through 252r of FIG. 2 or antenna 306 of FIG. 3), frequency bands, channels, and / or body positions, as described further below.

[0061]

[0065] A PD distribution (also called a PD map) for each transmission scenario may be generated based on measurements (e.g., electric field measurements) performed in a test laboratory using a human body model. After the PD distribution is generated, it is stored in memory to enable a processor (e.g., processor 280 of FIG. 2 or controller 336 of FIG. 3) to assess RF exposure in real time, as described further below. Each PD distribution includes a set of PD values, where each PD value may correspond to a different location (e.g., on the human body model).

[0062]

[0066] The PD value in each PD distribution corresponds to a particular transmit power level (e.g., the transmit power level at which the PD value was measured in a test laboratory). Because PD scales with transmit power level, the processor may scale the PD distribution for any transmit power level by multiplying each PD value in the PD distribution by a transmit power scaler:

[0063]

number

[0064] where Tx c is the current transmit power level for each transmission scenario, and Tx PDis the transmission power level corresponding to the PD value in the PD distribution (for example, the transmission power level at which the SAR value is measured in a testing laboratory).

[0065]

[0067] As described above, a wireless communication device may support multiple transmission scenarios for the second technology. In some aspects, a transmission scenario may be specified by a set of parameters. The set of parameters may include one or more of: an antenna parameter indicating one or more antennas used for transmission (i.e., active antennas); a frequency band parameter indicating one or more frequency bands used for transmission (i.e., active frequency bands); a channel parameter indicating one or more channels used for transmission (i.e., active channels); a body posture parameter indicating the location of the wireless communication device relative to a user's body location (head, trunk, away from the body, etc.); and / or other parameters. When a wireless communication device supports a large number of transmission scenarios, performing measurements for each transmission scenario in a test setting (e.g., a test laboratory) may be very time-consuming and expensive. To reduce test time, measurements may be performed on a subset of the transmission scenarios to generate a PD distribution for the subset of transmission scenarios. In this example, the PD distribution for each of the remaining transmission scenarios may be generated by combining two or more of the PD distributions for the subset of transmission scenarios, as described further below.

[0066]

[0068] For example, PD measurements may be performed on each of the antennas to generate a PD distribution for each of the antennas. In this example, a PD distribution for a transmit scenario in which two or more of the antennas are active may be generated by combining the PD distributions for the two or more active antennas.

[0067]

[0069] In another example, PD measurements may be performed for each of a plurality of frequency bands to generate a PD distribution for each of the plurality of frequency bands. In this example, a PD distribution for a transmission scenario in which more than one frequency band is active may be generated by combining the PD distributions for the two or more active frequency bands.

[0068]

[0070] In some embodiments, the PD distribution may be normalized with respect to the PD limit by dividing each PD value in the PD distribution by the PD limit, where the normalized PD value exceeds the PD limit when the normalized PD value is greater than 1 and is below the PD limit when the normalized PD value is less than 1. In these embodiments, each of the PD distributions stored in memory may be normalized with respect to the PD limit.

[0069]

[0071] In some aspects, a normalized PD distribution for a transmission scenario may be generated by combining two or more normalized PD distributions. For example, a normalized PD distribution for a transmission scenario in which two or more antennas are active may be generated by combining the normalized PD distributions for two or more active antennas. If different transmit power levels are used for the active antennas, the normalized PD distribution for each active antenna may be scaled by its respective transmit power level before combining the normalized PD distributions for the active antennas. The normalized PD distribution for simultaneous transmission from multiple active antennas may be given by:

[0070]

number

[0071] Here, PD lim is the PD limit, and PD norm_combined is the combined normalized PD distribution for simultaneous transmission from the active antennas, i is the index for the active antenna, and PD i is the PD distribution for the i-th active antenna, and Txi is the transmit power level for the i-th active antenna, and Tx PDi is the transmit power level for the PD distribution for the i-th active antenna, and L is the number of active antennas.

[0072] Equation (5) can be rewritten as follows:

[0073]

number

[0074] Here, PD norm_i is the normalized PD distribution for the i-th active antenna. In the case of simultaneous transmission using multiple active antennas at the same transmission frequency (e.g., MIMO), the combined normalized PD distribution may be obtained by adding the square roots of the individual normalized PD distributions and calculating the square of the sum, as given by:

[0075]

number

[0076] In another example, normalized PD distributions for different frequency bands may be stored in memory. In this example, a normalized PD distribution for a transmission scenario in which two or more frequency bands are active may be generated by combining the normalized PD distributions for two or more active frequency bands. If the transmit power levels for the active frequency bands are different, the normalized PD distribution for each of the active frequency bands may be scaled by the respective transmit power levels before combining the normalized PD distributions for the active frequency bands. In this example, the combined PD distribution may also be calculated using Equation (6a), where i is an index for the active frequency band and PD norm_i is the normalized PD distribution for the i-th active frequency band, and Tx iis the transmit power level for the i-th active frequency band, and Tx PDi is the transmit power level for the normalized PD distribution for the i-th active frequency band.

[0077] Exemplary RF Exposure Combinations As described above, UE 120 may simultaneously transmit signals using a first technology (e.g., 3G, 4G, IEEE 802.11ac, etc.) and a second technology (e.g., 5G, IEEE 802.11ad, etc.), and RF exposure is measured using different metrics for the first and second technologies (e.g., SAR for the first technology and PD for the second technology). In this case, processor 280 may determine a first maximum allowable power level for the first technology and a second maximum allowable power level for the second technology for transmission in a future time slot that complies with the RF exposure limits. During the future time slot, the transmit power levels for the first and second technologies are constrained (i.e., limited) by the determined first and second maximum allowable power levels, respectively, to ensure compliance with the RF exposure limits, as further described below. In this disclosure, the term "maximum allowable power level" refers to the "maximum permissible power level" imposed by RF exposure limits, unless otherwise specified. It should be appreciated that the "maximum permissible power level" is not necessarily equal to the absolute maximum power level that complies with RF exposure limits, and may be less than the absolute maximum power level that complies with RF exposure limits (e.g., to provide a safety margin). The "maximum permissible power level" may be used to set a power level limit for transmissions at a transmitter, such that the power level of the transmission cannot exceed the "maximum permissible power level" to ensure RF exposure compliance.

[0078] The processor 280 may determine the first and second maximum allowable power levels as follows: The processor may determine a normalized SAR distribution for a first technology at a first transmit power level, a normalized PD distribution for a second technology at a second transmit power level, and combine the normalized SAR distribution and the normalized PD distribution to generate a combined normalized RF exposure distribution (hereinafter simply referred to as the combined normalized distribution). The value at each location in the combined normalized distribution may be determined by combining the normalized SAR value at the location with the normalized PD value at the location or by another technique.

[0079] Processor 280 may then determine whether the first and second transmit power levels comply with RF exposure limits by comparing the peak value in the combined normalized distribution with 1. If the peak value is less than or equal to 1 (i.e., the condition ≦1 is satisfied), processor 280 may determine that the first and second transmit power levels comply with RF exposure limits (e.g., SAR limit and PD limit) and use the first and second transmit power levels as the first and second maximum allowed power levels, respectively, during future time slots. If the peak value is greater than 1, processor 280 may determine that the first and second transmit power levels do not comply with RF exposure limits. The condition for RF exposure compliance for simultaneous transmission using the first and second technologies may be given by:

[0080]

number

[0081] 4 is a diagram illustrating a normalized SAR distribution 410 and a normalized PD distribution 420, which are combined to generate a combined normalized distribution 430. FIG. 4 also illustrates the condition under which the peak value in the combined normalized distribution 430 is less than or equal to 1 for RF exposure matching. While each of the distributions 410, 420, and 430 are shown as two-dimensional distributions in FIG. 4, it should be appreciated that the disclosure is not limited to this example.

[0082]

[0078] The normalized SAR distribution in equation (7) may be generated by combining two or more normalized SAR distributions (e.g., for a transmit scenario using multiple active antennas), as described above. Similarly, the normalized PD distribution in equation (7) may be generated by combining two or more normalized PD distributions (e.g., for a transmit scenario using multiple active antennas), as described above. In this case, the condition for RF exposure compliance in equation (7) may be rewritten using equations (3a) and (6a) as follows:

[0083]

number

[0084] For the MIMO case, Equation (3b) and Equation (6b) can be combined instead. As shown in Equation (8), the combined normalized distribution can be a function of the transmit power level for the first technology and the transmit power level for the second technology. All points in the combined normalized distribution must satisfy the normalization constraint of 1 in Equation (8). Furthermore, when combining the SAR and PD distributions, the SAR and PD distributions must be spatially aligned, or their peak locations must be aligned, so that the combined distribution given by Equation (8) represents the combined RF exposure of a given location on the human body.

[0085] Exemplary RF Exposure Measurements As described above, UE 120 may simultaneously transmit signals using a first technology (e.g., 3G, 4G, IEEE802.11ac, etc.) and a second technology (e.g., 5G, IEEE802.11ad, etc.), and RF exposure is measured using different metrics for the first and second technologies (e.g., SAR for the first technology and PD for the second technology). The RF exposure measurements are performed differently for each transmission scenario and may include, for example, electric field measurements using a human body model. RF exposure distributions (simulations and / or measurements) may then be generated for each transmit antenna / configuration (beam) (as described above) over all evaluation surfaces / positions at all locations.

[0086] 5 illustrates an example system 500 for measuring RF exposure distribution in accordance with some aspects of the present disclosure. As shown, the RF exposure measurement system 500 includes a processing system 502, a robotic RF probe 504, and a human body model 506. The RF exposure measurement system 500 may perform RF measurements under various transmission and / or exposure scenarios associated with the UE 120 to assess a suitable back-off factor for the transmit power of the antenna 252 in accordance with one or more RF exposure limits. In other words, the UE 120 may emit electromagnetic radiation via the antenna 252 at various transmit powers, and the RF exposure measurement system 500 may perform RF measurements via the robotic RF probe 504 to determine a back-off factor for the antenna 252.

[0087] The processing system 502 may include a processor 508 coupled to a memory 510 via a bus 512. The processing system 502 may be a computing device such as a computer. The processor 508 may be a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor 508 may be in communication with the robotic RF probe 504 via an interface 514 (such as a computer bus interface), so that the processor 508 can, for example, acquire RF measurements made by the robotic RF probe 504 and control the position of the robotic RF probe 504 relative to the human body model 506.

[0088] Memory 510 may be configured to store instructions (e.g., computer-executable code) that, when executed by processor 508, cause processor 508 to perform various operations. For example, memory 510 may store instructions for obtaining RF exposure distributions associated with various RF exposure / transmission scenarios and / or adjusting the position of robotic RF probe 504.

[0089] The robotic RF probe 504 may include an RF probe 516 coupled to a robotic arm 518. In an aspect, the RF probe 516 may be a dosimetry probe capable of measuring RF exposure at various frequencies, such as the sub-6 GHz band and / or the mmWave band. The RF probe 516 may be positioned by the robotic arm 518 at various locations (indicated by dashed arrows) to capture electromagnetic radiation emitted by the antenna 252 of the UE 120. The robotic arm 518 may be a six-axis robot capable of performing precise movements to position the RF probe 516 at a location (on the human body model 506) of the maximum electromagnetic field generated by the UE 120. In other words, the robotic arm 518 may provide six degrees of freedom in positioning the RF probe 516 relative to the antenna 252 of the UE 120 and / or the human body model 506.

[0090] The human body model 506 may be a particular anthropomorphic mannequin with simulated human tissue. For example, the human body model 506 may include one or more fluids simulating human tissue in the head, torso, and / or limbs. The human body model 506 may simulate human tissue to determine the maximum allowable transmit power of the antenna 252 according to various RF exposure limits.

[0091]

[0085] Although the example shown in Figure 5 is described herein with respect to obtaining an RF exposure distribution using a robotic RF probe for ease of understanding, aspects of the present disclosure may also be applied to other suitable RF probe architectures, such as using multiple fixed RF probes positioned at various locations along the human body model 506.

[0092] Exemplary Transmit Antenna Grouping A multimode / multiband UE has multiple transmit antennas that can simultaneously transmit in sub-6 GHz bands and bands greater than 6 GHz, such as mmWave bands. As described herein, RF exposure in sub-6 GHz bands may be evaluated in terms of SAR, and RF exposure in bands greater than 6 GHz may be evaluated in terms of PD. Due to regulations regarding simultaneous exposure, wireless communication devices may limit the maximum transmit power for both sub-6 GHz bands and bands greater than 6 GHz.

[0093]

[0087] In some cases, although antennas may be located at different locations across the UE, the time-averaging algorithm for RF exposure adaptation may assume that all transmit antennas are co-located in a central location on the UE. Under such an assumption, the total transmit power of all transmit antennas may be limited regardless of the actual exposure scenario of the individual antennas (e.g., head exposure, torso exposure, or limb exposure). For example, assume that a user's hand covers the location of the co-located model, but that certain antennas are not covered by the user's hand. That is, antennas may contribute differently to RF exposure depending on the location of the exposure. Forcing the co-located model may lead to limiting the transmit power of certain antennas that are not actually covered by the user's hand. That is, assuming that transmit antennas are co-located for RF exposure adaptation may provide unnecessarily low transmit power, which may affect uplink performance, such as uplink data rate, uplink carrier aggregation, and / or uplink connectivity, at the edge of the cell.

[0094] Aspects of the present disclosure provide various techniques for grouping antennas to determine RF exposure adaptation, for example, on a group basis. In aspects, antenna groups may be defined and / or operated to be mutually exclusive of one another in terms of RF exposure. RF exposure adaptation and corresponding transmit power levels may be determined separately for each antenna group. Antenna grouping as described herein may enable relatively higher transmit power for a particular antenna group. Antenna grouping may refer to a specific assignment (or grouping) of antennas to separate antenna groups. Higher transmit power may provide desirable uplink performance, such as desirable uplink data rates, uplink carrier aggregation, and / or uplink connectivity at the edge of a cell.

[0095] In some aspects, multiple antenna groups are defined. Each antenna group may include one or more antennas. For example, antenna 252a may be categorized into a first antenna group, and antenna 252t may be categorized into a second antenna group. In some aspects, each antenna array (e.g., each phased array) is arranged in a different group. The groups may be defined manually, for example, by a designer or test operator, or in an automated manner, for example, by an algorithm operating prior to, during, or during device operation. Groups may be established based on physical location, operating frequency, form factor, associated method of calculating RF exposure, etc. (as described in more detail below).

[0096] FIG. 6 is a flow diagram illustrating example operations 600 for grouping antennas for RF exposure adaptation according to some aspects of the present disclosure. The operations 600 may be performed by, for example, a processing system including a UE (e.g., UE 120a in wireless communications network 100), an RF exposure measurement system (e.g., RF exposure measurement system 500), and / or a computing device such as a computer. The operations 600 may be implemented as software components executing and operating on one or more processors (e.g., controller / processor 280 of FIG. 2 and / or processor 508 of FIG. 5). Furthermore, transmission and / or reception of signals by the UE or RF exposure test system in operations 600 may be enabled by, for example, one or more antennas (e.g., antenna 252 of FIG. 2 and / or RF probe 516 of FIG. 5). In some aspects, transmission and / or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller / processor 280) that acquire and / or output the signals.

[0097] The operations 600 may begin at block 602, where a processing system may determine (e.g., generate and / or receive) an RF exposure distribution for each transmit antenna configuration for multiple transmit antennas of a wireless communication device (such as UE 120 shown in FIG. 5). At block 604, the processing system may assign the multiple transmit antennas to multiple antenna groups based on the RF exposure distribution. Optionally, at block 606, the UE and / or the processing system may determine a back-off factor for at least one of the multiple antenna groups associated with a particular exposure / transmission scenario, for example. At block 608, the UE may transmit from at least one antenna in at least one of the multiple antenna groups using a transmit power level based on the back-off factor.

[0098] In some aspects, assigning the multiple transmit antennas to the multiple antenna groups in block 604 may involve a processing system determining a back-off factor for each of the antenna groups, e.g., as further described herein with respect to FIG. 8. A back-off factor, as used herein, may be a particular number that represents a fraction (or portion) of the maximum transmit power level supported by the UE, such as a number ranging from 0 to 1. For example, the processing system may generate normalized distributions of the RF exposure distribution, generate a normalized composite map of the normalized distributions for each of the antenna groups, and generate a total normalized composite map for all of the antenna groups based on the back-off factor associated with each of the antenna groups.

[0099] In aspects, the normalized distribution may be generated by dividing the RF exposure distribution by the maximum RF exposure value for the corresponding transmit antenna configuration, e.g., as described herein with respect to block 802. In aspects, the normalized composite map may be generated by selecting the maximum of the normalized distribution as the normalized composite map for each of the antenna groups, e.g., as described herein with respect to block 804.

[0100] In some aspects, generating the sum of the normalized composite maps may be generated by multiplying the normalized composite maps for each antenna group by an associated back-off factor and summing the weighted normalized composite maps together to generate a weighted normalized composite map for each antenna group, e.g., as described herein with respect to block 808. In some aspects, at least one of the back-off factors may be adjusted and applied to calculating the sum of the normalized composite maps until the sum of the normalized composite maps is less than or equal to a first threshold (e.g., 1.0). That is, the back-off factor associated with each antenna group may be updated and applied to calculating the normalized composite map until the sum of the normalized composite maps is less than or equal to the first threshold.

[0101] In some cases, the processing system may assign each of the multiple transmit antennas to one of the multiple antenna groups based on the RF exposure distribution, so that the transmit antenna is not in the multiple antenna groups. In some cases, the processing system may assign each of the multiple transmit antennas to one of the multiple antenna groups based on the RF exposure distribution, so that at least one transmit antenna is in the multiple antenna groups.

[0102] In an aspect, multiple transmit antennas may be assigned to multiple antenna groups at block 604 based on the determined back-off factor values, e.g., as further described herein with respect to FIG. 9. If one of the back-off factors is less than a second threshold (e.g., 0.5), the transmit antennas may be redistributed or regrouped. For example, the processing system may determine back-off factors for a first grouping of antenna groups, e.g., as described herein with respect to FIG. 8, and assign transmit antennas to a second grouping of antenna groups if at least one of the back-off factors for the first grouping is less than a second threshold (e.g., 0.5). In some cases, the first grouping may include a separate antenna group for each transmit antenna, and the second grouping may include at least one antenna group having multiple transmit antennas. That is, a first iteration of the antenna grouping procedure may involve determining a back-off factor for each antenna and determining which transmit antennas to group together based on the back-off factors, and subsequent iterations may refine or adjust the assignment of antennas to particular antenna groups, for example, based on the determined back-off factors.

[0103] The processing system may repeat determining back-off factors and assigning transmit antennas to antenna groups until all of the back-off factors are greater than a second threshold. For example, the processing system may determine back-off factors for a second grouping of antenna groups (e.g., repeating the operations described herein with respect to FIG. 8) and assign transmit antennas to a third grouping of antenna groups if at least one of the back-off factors for the second grouping is less than a threshold. In some cases, the third grouping may include at least two antenna groups with multiple transmit antennas in each of the at least two antenna groups. That is, the assignment of the third grouping may further refine antenna groups including multiple antennas in three or more antenna groups.

[0104] In some aspects, the antenna group may include a mixed-mode antenna (e.g., a sub-6 GHz antenna and an mmWave antenna). For example, at least one of the antenna groups may include a first antenna configured to transmit in a first mode and a second antenna configured to transmit in a second mode. The first mode may be a transmission mode in the sub-6 GHz band, and the second mode may be a transmission mode in the mmWave band. In other words, the first mode may be transmitting at one or more frequencies below 6 GHz (e.g., 300 MHz to 6 GHz), and the second mode may be transmitting at one or more frequencies above 6 GHz (e.g., 24 GHz to 53 GHz or higher). That is, the first mode may include a first antenna operable at one or more frequencies below 6 GHz, and the second mode may include a second antenna operable at one or more frequencies above 6 GHz.

[0105] In an aspect, the transmit antenna configuration may include a transmit beam configuration of a particular antenna or an antenna module having multiple antennas. In an aspect, at least one of the transmit antennas is part of an antenna module having multiple antennas. As an example, in block 602, an RF exposure distribution may be generated (and / or an indication thereof may be received) for each antenna among the multiple antennas and / or for each transmit beam configuration supported by an antenna module among the multiple antennas. In an aspect, the transmit beam configuration may refer to a transmit radiation pattern from an antenna or antenna module in a certain azimuth direction and / or elevation direction that may be achieved through beamforming. The transmit beam configuration may have a transmit power spread (e.g., a power angle spread related to the departure angle) in the azimuth direction and / or elevation direction.

[0106] In some cases, the grouping of antennas may be used to determine RF exposure conformance and corresponding transmit power levels. For example, the UE may transmit a signal at a certain transmit power level based on enforcing RF exposure conformance for at least one of the antenna groups. In some aspects, enforcing RF exposure conformance may involve the UE determining whether to transmit a signal at a certain RF exposure limit (e.g., a SAR limit of 1.6 watts per kilogram (1.6W / kg) and / or a SAR limit of 1.0 milliwatts per square centimeter (1.0mW / cm 2 ) the PD limit of the IEEE 802.11b / g / n transmission power limit.

[0107] In aspects, ensuring RF exposure compliance may include evaluating RF exposure compliance in terms of time-averaged RF exposure, such as time-averaged SAR or time-averaged PD, over a time window. In aspects, the time window may range from 1 second to 360 seconds. For example, the time window may be 100 seconds or 360 seconds. The range from 1 second to 360 seconds is an example, and other suitable values ​​for the time window may be used. In some cases, the time window may be shorter than 1 second, such as 500 milliseconds. In some cases, the time window may be longer than 360 seconds, such as 600 seconds.

[0108] In an aspect, a UE may be in communication with a base station, such as the BS 110. For example, in block 608, the UE may be transmitting user data on a physical uplink shared channel (PUSCH) or various uplink feedback (e.g., uplink control information or hybrid automatic repeat request (HARQ) feedback) on a physical uplink control channel (PUCCH) to the base station. In some cases, the UE may be in communication with another UE. For example, in block 608, the UE may be transmitting user data and / or various feedback on a sidelink channel to the other UE.

[0109] 7 is a block diagram illustrating an example grouping of multiple antennas of a wireless communication device 700, in accordance with certain aspects of the present disclosure. In this example, a wireless communication device 700 (e.g., a UE 120 such as a smartphone or any of the wireless communication devices described herein) includes a first antenna 702a, a second antenna 702b, a third antenna 702c, a fourth antenna 702d, a fifth antenna 702e, a sixth antenna 702f, and a seventh antenna 702g. In this example, the antennas 702a-702g are separated into three antenna groups 704, 706, 708 that correspond approximately to the top of the device 700, the bottom of the device 700, and the sides of the device 700 when the device 700 is held in an upright position. Those skilled in the art will appreciate that more or fewer than seven antennas may be implemented and / or more or fewer than three antenna groupings may be defined. Each of the illustrated antennas 702a-702g may represent a single antenna, an array of antennas (e.g., a phased array), or a module including one or more antennas. Antenna groups 704, 706, 708 may each include one or more antennas configured to transmit in a frequency band (e.g., very high (e.g., mmWave band), high (e.g., 6-7 GHz band), mid (e.g., 3-6 GHz band), or low (e.g., 400 MHz-3 GHz band)), or each antenna group may include one or more antennas configured to transmit in multiple frequency bands.

[0110] In aspects, the mutually exclusive antenna groupings described herein may be assigned to various antenna groupings (such as an mmWave grouping, a sub-6 GHz grouping, a low-band grouping (e.g., 400 MHz to 3 GHz band), a mixed-mode grouping (e.g., an mmWave and sub-6 GHz grouping)) for different transmission scenarios. As an example, under the mmWave grouping, each mmWave module (e.g., the first antenna 702a, the third antenna 702c, and the fifth antenna 702e) may be treated as a separate antenna group, where each mmWave module may have multiple antenna elements (e.g., 64 dual-polarized antenna elements) arranged in one or more arrays. The mmWave modules may be capable of transmitting various beams via predefined antenna configurations, where the beams may form a codebook. Under the sub-6 GHz grouping, the sub-6 GHz antennas may be grouped into separate groups. For example, the second and fourth antennas 702b, 702d may be assigned to one group, and the sixth and seventh antennas 702f, 702g may be assigned to another group. In some cases, the antennas 702a-702g may be assigned to mixed-mode groupings, such as three antenna groups 704, 706, 708.

[0111] Groups may be defined and / or operated to be mutually exclusive in terms of RF exposure. In some aspects, the transmit power of one or more of the groups (or one or more of the antennas in one or more groups) may be reduced so that the (normalized) sum of the exposures of all antenna groups or of overlapping RF exposure distributions is less than a certain value (e.g., 1.0). For example, a back-off factor may be determined for one or more groups or one or more antennas in one or more groups and applied to limit the transmit power for the antennas and / or groups.

[0112]

[0106] As an example, the back-off factor bf may be between [0,1] for each antenna group, and therefore the maximum allowed transmit power for each antenna group is equal to the respective back-off factor multiplied by the transmit power limit of the antenna group (e.g., bf*Tx_power_limit), where bf=1 represents no back-off, and where bf=0.3 means operating the antenna group at 30% of the transmit power limit, where the transmit power limit may be the maximum transmit power supported by that particular antenna and / or antenna group.

[0113] FIG. 8 is a flow diagram illustrating example operations 800 for determining back-off factors for antenna groups according to some aspects of the present disclosure. The operations 800 may be performed, for example, by a UE (e.g., UE 120a in wireless communication network 100), an RF exposure measurement system (e.g., RF exposure measurement system 500), and / or a processing system. To determine such back-off factors, at block 802, an RF exposure distribution (simulation and / or measurement) may be generated for each transmit antenna / configuration (beam) (as described above) over all evaluation surfaces / positions at all locations using, for example, the processing system and / or RF exposure measurement system 500. In some aspects, the RF exposure distribution may be generated via simulation, such as simulating various exposure / transmission scenarios using a model of a human body exposed to electromagnetic radiation from a wireless communication device. As previously described herein, the RF exposure distribution may include RF exposure associated with various transmission scenarios corresponding to particular frequency bands and / or human body positions relative to antennas. For example, an RF exposure distribution may be represented by the formula RFexp(s,x,y,z,i), where s represents a particular surface or position, (x,y,z) represents a given location, and i represents a particular transmit configuration, such as a particular antenna or transmit beam. In some cases, a transmit antenna may support multiple bands, so multiple RF exposure distributions for each band / channel (low / mid / high) may be available for a particular transmit antenna. In that case, the RF exposure distribution for a particular transmit antenna may represent the maximum exposure among all technologies / bands / channels supported by the transmit antenna at each location / exposure surface.

[0114] Then, in block 804, a normalized distribution (map) may be calculated by collecting the exposure on all surfaces / positions for each transmit antenna / beam and dividing by the corresponding maximum value. For example, the normalized distribution may be represented by the formula: normalized.map(s,x,y,z,i)={RFexp(1,x,y,z,i);RFexp(2,x,y,z,i);...;RFexp(s,x,y,z,i)} / maxRFexp(i).

[0115] Thereafter, in block 806, a normalized composite map for each antenna group may be calculated, for example, based on the maximum value of the normalized distributions in the group. That is, generating the normalized composite map may include selecting the maximum normalized distribution among the normalized distributions in a particular antenna group. For example, the normalized composite map may be calculated using the formula: normalized.composite.map.AG k (s,x,y,z)=maximum{normalized.map(s,x,y,z,i),∀ i =AG k 1 to n antennas / beams in {A, B, C, D, E ... k represents a particular antenna group (AG).

[0116] Further, at block 808, a summed normalized combining map may be calculated for all of the antenna groups, e.g., based on the sum of all of the normalized combining maps. As an example, the summed normalized combining map may be given by the following equation:

[0117]

number

[0118] where bf k represents the back-off factor for a particular antenna group.

[0119] In some aspects, in block 810, it may be determined whether the summed normalized composite map is less than a threshold value (e.g., 1.0). If this condition is not met, the expected or potential power for one or more antennas (or one or more antenna groups) may be reduced using updated back-off factors. Antenna groups may contribute to RF exposure at different levels depending, for example, on the location of the antennas within the group, the supported bands of the antennas within the group, the maximum transmit power of the antennas within the group, etc. The contribution of the antenna group to RF exposure (e.g., based on the summed normalized composite map, where overlapping maps are at peaks, etc.) may be adjusted using the back-off factor for the antenna group. In block 812, for example, the back-off factor may be adjusted (increased or decreased) for one or more of the antenna groups, and the summed normalized composite map may be recalculated using the updated back-off factors in block 808. The back-off factor for each antenna and / or group may be adjusted (or updated) until the condition at block 810 is met (e.g., the summed normalized composite map is less than or equal to a threshold), and the summed normalized composite map may be recalculated using the adjusted back-off factor. In some examples, the back-off factor for each transmitter (or antenna or group of antennas or transmitters) may be determined based on the ratio of the RF exposure due to each transmitter at a (e.g., peak) location to the desired amount of exposure reduction. In some examples, the back-off factor may be determined based on the priority of the transmitters coupled to the antenna. In some examples, the back-off factor for the antenna that contributes the most to the RF exposure at (e.g., peak) is the largest back-off factor compared to the back-off factors for other antennas or groups. In some examples, the back-off factors are determined such that the transmit power level for each of several antennas or groups contributes approximately equally to the RF exposure at a location.The back-off factors may be determined or applied uniformly to the antennas in the group, or may vary across the antennas in the group.

[0120] At block 814, if the summed normalized composite maps are less than a threshold value (e.g., 1.0), the antenna groups may be deemed mutually exclusive in terms of RF exposure, and a final back-off factor for each antenna group may be obtained at block 816. The back-off factors may be used to determine transmit power levels for particular antenna groups, as described further herein, or for other purposes, such as determining actual or potential interference.

[0121] 9 is a flow diagram illustrating example operations 900 for assigning antennas to groups based on back-off factors (e.g., determined in operation 800) in accordance with certain aspects of the present disclosure. The operations 900 may be performed, for example, by a processing system including a UE (e.g., UE 120a in wireless communications network 100) and / or an RF exposure measurement system (e.g., RF exposure measurement system 500).

[0122] For example, after completing operation 800 with several antenna groupings, back-off factors for each antenna group may be obtained in block 902. For example, operation 800 may first be performed using separate groups for each of the antennas / beams to obtain back-off factors for the individual antennas in block 902.

[0123] In block 904, it may be determined whether each of the back-off factors is greater than or equal to a threshold value (e.g., 0.5). If this condition is not met, in block 906, the antennas may be reassigned or redistributed among the antenna groups. In some cases, if an antenna / antenna group has a low back-off factor (e.g., a back-off factor < 0.5), some of the antennas may be grouped together in the same antenna group based on spatial distribution, resulting in a reduction in the number of antenna groups. For example, assume that in the first iteration, a separate group is used for each antenna, where antennas 1 to 7 are in antenna groups AG1 to AG7, respectively. The corresponding back-off factors are as follows: bf1 = bf2 ≒ 0.5, bf3 ≒ 1, bf4 = bf5 = bf6 = bf7 ≒ 0.25. The updated antenna groups may then be AG1 = {Ant4, Ant5, Ant6, Ant7}, AG2 = {Ant1, Ant2}, and AG3 = {Ant3}. In some cases, particular antennas may be grouped together such that the sum of the back-off factors for the particular antennas exceeds a threshold in block 904. In block 902, operation 800 or portions of operation 800 (e.g., blocks 806-816) may be repeated to determine updated back-off factors for the reallocated antenna groups. The antenna grouping / back-off factor generation may be repeated until all of the back-off factors satisfy the conditions in both blocks 810 and 904. If the conditions in these blocks are met, the antenna group assignment may be considered complete.

[0124] The antenna grouping operations described herein may be determined and / or applied for each device status index (DSI) indicating an exposure scenario (e.g., head exposure, torso exposure, or limb exposure) of the device. For example, a head exposure may have four exposure locations (right cheek, right tilt, left cheek, and left tilt), and these four locations may be collected together (e.g., in a normalization map at block 804). (In some cases, the value of s will be in the range of [1, 4] to account for the four exposure locations, where s represents a particular surface or location.) A torso exposure may have two exposure locations (from the front and back), and these two exposure locations may be collected together (e.g., at block 804). A limb exposure may have six exposure locations (front, back, left, right, top, and bottom of the device) with a separation distance of 0 mm, and these six locations may be collected together (e.g., at block 804).

[0125]

[0117] In some aspects, the antenna grouping operations described herein may be combined with existing techniques for some exposure configurations, for example, if the absolute sum of the maximum RF exposure values ​​of all antenna groups (e.g., the summed normalized composite map) is less than a regulatory limit, the above procedure of adjusting the power / backoff factors may be skipped.

[0126] Although the examples provided herein are described with respect to the UE performing various operations in determining antenna grouping, aspects of the present disclosure may also be applied to scenarios in which the antenna grouping and back-off factor derivation operations are performed in a laboratory setting (such as with RF exposure measurement system 500), with some calculations or simulations being performed outside the UE, for example, by a separate processing system (such as processing system 502). That is, the various functions for the antenna grouping and back-off factor derivation operations need not be performed in the UE itself, but that UE may be configured to store / access / utilize certain information derived from the antenna grouping operations, such as assignment of back-off factors and antenna groupings. For example, antenna grouping assignments and corresponding back-off factors may be developed using a wireless communication device (prototype) in a laboratory setting (e.g., RF exposure measurement system 500) to simulate various exposure / transmission scenarios during an RF exposure compliance certification process with a regulatory body, and the UE may be configured to store / access / utilize the back-off factors associated with particular antenna groupings derived from the antenna grouping operations performed in the laboratory setting.

[0127] As an example, a UE may store and access various back-off factors associated with particular antenna groups and / or transmit beam configurations according to various RF exposure limits associated with exposure / transmission scenarios (such as head exposure, torso exposure, and / or limb exposure in some frequency bands). The back-off factors associated with particular antenna groups and / or transit beam configurations may be developed, for example, in accordance with operations for assigning antenna groups as described herein using a prototype UE in an RF exposure test laboratory. The back-off factors associated with particular antenna groups may be arranged in a data structure, such as a table or database, of back-off factors associated with particular antenna groupings and / or particular exposure / transmission scenarios in particular frequency bands.

[0128] Although the examples provided herein are described with respect to a UE performing RF exposure matching with antenna groupings, aspects of the present disclosure are not limited to RF exposure use cases. For example, stored values ​​derived from antenna grouping operations (e.g., back-off factors and / or antenna grouping assignments) may be used for any number of applications. One application, described further below, is evaluating RF exposure matching using back-off factors and / or antenna groupings. Another application could be determining self-interference between antenna groupings based on transmit power levels. Other purposes are also possible.

[0129] In some cases, an antenna may not meet the exclusion criteria of another antenna group, in which case the antenna may be incorporated into another antenna group. In some cases, this may lead to all of the antennas being combined into a single antenna group, which implies that the RF exposure from all antennas is co-located and does not take advantage of the spatial diversity due to the antenna placement. One way to avoid this is to make the antenna meet the exclusion criteria by applying a higher permanent backoff to one or more antennas.

[0130] Aspects of the present disclosure relate to assigning antennas to multiple antenna groups within a particular antenna grouping. For example, an antenna may be assigned to multiple antenna groups if it does not meet the exclusion criteria of another antenna group, which may avoid applying a permanent backoff to all of the antennas. The antenna groupings described herein may enable flexibility to adapt desired transmit power for a particular antenna group and / or RF exposure limits per antenna group.

[0131] Aspects of the present disclosure relate to, for example, assigning one or more antennas to multiple sets of antenna groups (i.e., multiple antenna groupings) for distinct transmission scenarios. For example, a processing system may develop antenna groupings for a particular country or region (which may be identified, for example, by a Public Land Mobile Network (PLMN) code and / or a Mobile Country Code (MCC)) due to distinct RF exposure requirements for that country or region. In some cases, the processing system may develop antenna groupings for particular exposure scenarios such as head exposure, torso exposure, limb exposure, and / or hot spot exposure (e.g., when the wireless communication device is not in close proximity to human tissue) and / or antenna groupings based on one or more operating conditions (e.g., whether MIMO is utilized, when several high-priority applications or transmissions may be active for some bands, etc.). Antenna groupings per transmission scenario (e.g., particular region and / or exposure scenario) may provide the wireless communication device with the flexibility to switch between antenna groupings depending on the transmission scenario the wireless communication device encounters.

[0132] 6, operations 600 may further involve a processing system (e.g., a UE, an RF exposure measurement system, a computer separate from the UE, and / or any other device configured to perform the operations described herein) assigning at least one of the transmit antennas to two or more of the antenna groups in block 604. For example, the processing system may assign an antenna to multiple antenna groups by the antenna not meeting an exclusion criterion with other antenna groups. In block 604, the processing system may identify that at least one of the transmit antennas does not meet a mutually exclusive criterion with at least two of the antenna groups, and the processing system may assign at least one of the transmit antennas to at least two of the antenna groups in response to the identification.

[0133] In some cases, the antenna may have a maximum time-averaged power limit (P limit ) to multiple antenna groups. The maximum time-averaged power limit may refer to the maximum constant transmit power that an antenna may transmit continuously throughout the duration of a time window associated with an RF exposure limit in accordance with the RF exposure limit. For example, if one antenna has a relatively low P limit , the processing system may not iteratively assign that particular antenna among multiple antenna groups to avoid consuming RF exposure margin among those antenna groups. As an example, if a particular antenna has a relatively high P limit , the processing system may assign that particular antenna to a plurality of antenna groups, where low or high P for a particular antenna (and particular technology / frequency band) limit is the maximum transmit power (P max ) for P limitIn such a scenario, the peak-to-average-power ratio (PAPR) can be quantified by comparing P limit The PAPR in dB can be used as a metric to determine whether P is relatively low or high. max -P limit where P max and P limit may be in dBm. For example, if the PAPR is positive (e.g., a few dB, e.g., 2 dB, 3 dB, or 6 dB), then P limit can be considered low for that particular technology / band / antenna. Similarly, if the PAPR is less than or negative than one of these example values, P limit may be considered high. For operation 600, the processing system may identify a maximum time-averaged power limit associated with each of the transmit antennas, and the processing system may assign at least one of the transmit antennas to at least two of the antenna groups based at least in part on the maximum time-averaged power limit associated with at least one of the transmit antennas.

[0134] In some aspects, the processing system may generate multiple antenna groupings. Antenna groupings may be developed for distinct transmission scenarios, such as when the wireless communication device is located in a particular region and / or when the wireless communication device experiences a particular exposure scenario. For operation 600, the processing system may assign transmit antennas to a first grouping of antenna groups for a first transmission scenario (e.g., when the UE is located in the United States) and assign transmit antennas to a second grouping of antenna groups for a second transmission scenario (e.g., when the UE is located in the European Union).

[0135] In some aspects, the first grouping may have a different arrangement of transmit antennas in the antenna groups than the second grouping. At least one of the transmit antennas is in both the first grouping and the second grouping. For example, referring to FIG. 7, antennas 702a-702g may be assigned to a first grouping, where the first antenna 702a, the second antenna 702b, the third antenna 702c, the fourth antenna 702d, and the fifth antenna 702e are assigned to the first group, and the fifth antenna 702e, the sixth antenna 702f, and the seventh antenna 702g are assigned to the second group. The first group may be spatially separated from the second group to provide a mutually exclusive relationship in terms of RF exposure. In this first grouping, the fifth antenna 702e is assigned to two different antenna groups (i.e., the first group and the second group). Because the fifth antenna 702e is located between the set of upper and lower antennas (702a-d, 702f, and 702g), it may be difficult to separate the fifth antenna 702e into mutually exclusive groups. For example, the fifth antenna 702e may interact with the other antennas (702a-d, 702f, and 702g), and to avoid applying a limited and persistent backoff, the fifth antenna 702e may be assigned to both the first group and the second group.

[0136] The antennas 702a-702g may also be assigned to a second grouping, where the first antenna 702a, the second antenna 702b, the third antenna 702c, and the fourth antenna 702d are assigned to the third group, the sixth antenna 702f and the seventh antenna 702g are assigned to the fourth group, and the fourth antenna 702d, the fifth antenna 702e, and the seventh antenna 702g are assigned to the fifth group. In this second grouping, the fourth antenna 702d is assigned to two different antenna groups (i.e., the third group and the fifth group), and the sixth antenna 702g is assigned to two different antenna groups (i.e., the fourth group and the fifth group). In this second grouping, the fifth antenna 702e may again be difficult to assign to a separate group, and the fifth antenna 702e may be grouped with antennas spatially located on the same side of the wireless communication device 700, such as the fourth antenna 702d and the seventh antenna 702g.

[0137] In some cases, the first transmission scenario may be associated with a first country or region (e.g., the United States), and the second transmission scenario may be associated with a second country or region (e.g., China or the European Union). That is, the first and second transmission scenarios may depend on the particular region in which the UE is located to comply with particular RF exposure limits for that region. When the UE is located in that particular region (e.g., determined based on a PLMN code and / or MCC assigned to the UE), the UE may use a certain antenna grouping associated with that region.

[0138] In some cases, the first transmission scenario may be associated with a first exposure scenario (e.g., head exposure), and the second transmission scenario may be associated with a second exposure scenario (e.g., torso exposure). That is, the first and second transmission scenarios may depend on a particular exposure scenario, such as head exposure, torso exposure, limb exposure, and / or hot spot exposure. When the UE encounters a particular exposure scenario, the UE may use a certain antenna grouping associated with that exposure scenario.

[0139] In some cases, a transmission scenario may be associated when several antennas are used for simultaneous transmission. For example, assume that the fourth antenna 702d and the seventh antenna 702g are generally to be used for simultaneous transmission. The processing system may assign these antennas to different groups to facilitate efficient use of RF exposure margins for these antennas. As an example, the processing system may develop a first grouping for when the fourth antenna 702d and the seventh antenna 702g are used for simultaneous transmission to enable application of separate backoffs for these antennas, as described herein with respect to FIG. 7.

[0140] For operation 600, the UE may transmit from at least one transmit antenna in a first grouping during a first transmission scenario, and the UE may transmit from at least one transmit antenna in a second grouping during a second transmission scenario. In other words, the UE may select which antenna grouping to use for a particular transmission scenario, and the UE may switch between antenna groupings when there is a change in transmission scenario, such as when the UE moves from one region to another, as described further herein with respect to FIG.

[0141] Exemplary Time-Averaged RF Exposure by Transmit Antenna Group Aspects of the present disclosure provide various techniques for determining time-averaged RF exposure adaptation for each transmit antenna group. Because the antenna grouping described herein may provide mutually exclusive antenna groups in terms of RF exposure, RF exposure adaptation for each antenna group may be determined separately. In some cases, RF exposure adaptation for antenna groups may be performed in parallel (e.g., simultaneously). The group-based RF exposure adaptation described herein may enable a desired transmit power for a particular antenna group, for example, due to different exposure scenarios encountered by each antenna group. The desired transmit power may provide desired uplink performance, such as a desired uplink data rate, uplink carrier aggregation, and / or uplink connectivity at the edge of the cell.

[0142] 10 is a flow diagram illustrating example operations 1000 for wireless communication in accordance with certain aspects of the present disclosure. The operations 1000 may be performed, for example, by a UE (e.g., UE 120a in wireless communication network 100). The operations 1000 may be implemented as software components executing and operating on one or more processors (e.g., controller / processor 280 of FIG. 2). Furthermore, transmission of signals by the UE in operations 1000 may be enabled, for example, by one or more antennas (e.g., antenna 252 of FIG. 2). In some aspects, transmission and / or reception of signals by the UE may be implemented via a bus interface of one or more processors (e.g., controller / processor 280) that acquire and / or output the signals.

[0143] The operations 1000 begin at block 1002, where a UE may access a stored back-off factor associated with an antenna group (e.g., antenna group 704) among multiple antenna groups (e.g., antenna groups 704, 706, 708). In block 1004, the UE may transmit a signal from at least one transmit antenna (e.g., antenna 702a) in the antenna group at a transmission power level based on the back-off factor in accordance with RF exposure requirements.

[0144] In some cases, the grouping of transmit antennas may not be an explicit indication of which antennas are in a particular group. In an aspect, the grouping of transmit antennas may be implicitly indicated by various back-off factors assigned to the transmit antennas for a particular exposure / transmission scenario. That is, the grouping of antennas and the assignment of antenna groups associated with the grouping of antennas may be represented by back-off factors. For example, some antennas may share the same back-off factor, and therefore, these antennas are implicitly assigned to the same antenna group among multiple antenna groups. In an aspect, the transmit power level may be based at least in part on at least one of the back-off factors.

[0145] In some aspects, the transmit power level may be determined based on a sum of RF exposures being less than or equal to a threshold (e.g., 1.0). For example, the UE may transmit a signal at a transmit power level based on the sum of the RF exposures for each of the antenna groups being less than or equal to a threshold. In some such scenarios, this is achieved by applying the back-off factor described above to the transmit power level.

[0146] In some aspects, the transmit power level may be determined based on the time-averaged RF exposure being less than a threshold. For example, the UE may transmit a signal at a transmit power level based on the time-averaged sum of the RF exposure for each of the antenna groups being less than or equal to a threshold (e.g., 1.0). A back-off factor may be applied to the sum of the RF exposure or the RF exposure for each of the antenna groups in the case of the time-averaged sum of the RF exposure.

[0147] In an aspect, the UE may determine a time-averaged RF exposure for each of the antenna groups and use the group-based time-averaged RF exposure in determining RF exposure adaptation. For example, the UE may transmit a signal at a transmit power level based on each of the time-averaged RF exposures being equal to or less than a threshold. In some cases, because the antenna groups may be mutually exclusive of each other in terms of RF exposure, the UE may simultaneously determine the time-averaged RF exposure for each of the antenna groups. In other words, the mutual exclusivity of the antenna groups may enable the UE to determine the time-averaged RF exposure for each of the antenna groups in parallel (e.g., independently) with each other. Expressed another way, the UE may use parallel (or simultaneous) processing to determine the time-averaged RF exposure for each or a portion of the antenna groups. For example, the UE may determine a time-averaged RF exposure associated with a first antenna group (e.g., antenna group 704) while simultaneously determining a time-averaged RF exposure associated with a second antenna group (e.g., antenna group 706), and the UE may determine a transmit power according to an RF exposure requirement for each of the first and second antenna groups based on the respective time-averaged RF exposures and respective back-off factors. In some cases, the UE may transmit a signal at a transmit power level based on enforcing RF exposure conformance for one of the multiple antenna groups having a lower transmit power limit than another one of the multiple antenna groups. That is, the minimum of the multiple transmit power limits may be enforced by the transmitter to ensure overall time-averaged RF exposure conformance.

[0148] In aspects, the antennas may have various antenna groupings, for example, as described herein with respect to operation 600. As an example, the UE may have back-off factors associated with an antenna group for the mmWave band, an antenna group for the sub-6 GHz band, and / or an antenna group for the mixed-mode band (the sub-6 GHz band and the mmWave band). In some cases, the antenna groupings may be derived using operations 600, 800, or 900. For example, at least one of the antenna groups may include a first antenna configured to transmit in a first mode and a second antenna configured to transmit in a second mode. In some cases, the first mode may be sub-6 GHz and the second mode may be mmWave. That is, the first mode may be transmitting in the sub-6 GHz band and the second mode may be transmitting in the mmWave band. In an aspect, the first mode may include a first antenna operable in the sub-6 GHz band, and the second mode may include a second antenna operable in the mmWave band.

[0149] In some aspects, the transmit antennas may include one or more first antennas configured to transmit in a first mode and one or more second antennas configured to transmit in a second mode. The first antennas may be separately assigned to antenna groups. That is, the first antennas may be divided into groups, and thus some of the first antennas may be in the same group, but one of the first antennas may not be assigned to more than one group in a particular antenna grouping. The second antennas may be included in each or some of the antenna groups. In some cases, each of the antenna groups may have all of the second antennas. In some cases, the first mode may be transmitting at one or more frequencies below 6 GHz (e.g., in a sub-6 GHz band), and the second mode may be transmitting at one or more frequencies above 6 GHz (e.g., in an mmWave band). In other cases, the first mode may be transmitting at one or more frequencies above 6 GHz, and the second mode may be transmitting at one or more frequencies below 6 GHz.

[0150] In an aspect, the transmit antennas are grouped such that each antenna group is mutually exclusive from all other antenna groups in terms of RF exposure. The mutual exclusivity of the antenna groups can be achieved using various techniques or criteria. For example, in a system of N antennas grouped into k antenna groups, the normalized RF exposure distribution initially obtained for each of i=1 to N antennas on all exposed surfaces of interest is equal to normalized.map(s,x,y,z,i) represented in block 804, and therefore the maximum value of the RF exposure distribution among all surfaces is max{normalized.map(s,x,y,z)}=1.0. Then, obtain a composite map = normalized.composite.map of all n antennas in antenna group k. AG k(s,x,y,z) is equal to max{normalized.map(s,x,y,z,i=1 to n)}) represented in block 806, which is equal to normRFexposure(k,s,x,y,z). This normalized composite map is called the normalized RF exposure for antenna group k. For example, mutual exclusivity of antenna groups may be given if the sum of RF exposures of all antenna groups (k=1 to M)<1.0 satisfies the following equation:

[0151]

number

[0152] Here, predefined backoff(k) is a backoff factor applied to all antennas and / or antenna configurations of antenna group “k.” The backoff factor may be determined based on operations 600, 800, and / or 900, and / or the backoff factor may be stored by the UE (e.g., in memory 282 or 338) and retrieved for use in performing operation 1000. In some cases, existing regulatory techniques that meet predefined criteria, such as SAR Peak Location Separation Ratio (SPLSR), may be used to determine such mutual exclusivity (e.g., as described in Section 4.3.2c of FCC KDB 447498 D01 General RF Exposure Guidance v06). In some cases, the mutual exclusivity of antenna groups may be determined by the sum of overlapping RF exposure distributions at a particular backoff factor being less than or equal to a threshold value (e.g., 1.0). The predefined backoff factor is between [0, 1] and applies to all antennas belonging to that antenna group. This can be achieved by lowering the maximum time-averaged transmit power limit for each antenna belonging to antenna group k by a predefined backoff(k). Alternatively, the total RF exposure for all antennas in antenna group k at all spatial locations (s, x, y, z) can be expressed as RFexposurelimit *The predefined backoff(k) must not be exceeded.

[0153] Because antenna groups are mutually exclusive, (real-time) averaging of RF exposure may be performed for each antenna group (e.g., regardless of other antenna groups) using the methods described above or using one or more other methods. For example, the RF exposure of a given antenna at any time instant t may be directly proportional to the transmit power of the antenna at t. Thus, the RF exposure for antenna i belonging to antenna group k at time instant t may be given by:

[0154]

number

[0155]

[0144] The time-averaged RF exposure of all n antennas and / or antenna configurations in antenna group k over a time window T may be given by:

[0156]

number

[0157] The predefined backoff may be a backoff factor bf as described herein.

[0158]

[0145] When antennas and / or groups of antennas that use different mechanisms (e.g., SAR or PD) to calculate RF exposure are included in an antenna group, the exposures may be combined as described herein or using one or more other methods or calculations.

[0159]

[0146] Thus, transmissions (power) using antennas in an antenna group may be controlled (e.g., by processor 280) such that each group individually meets exposure requirements defined, for example, by a regulator in a domestic or foreign jurisdiction. In some aspects, this may result in the total power transmitted across all of the antenna groups being higher than if the antennas were not divided into mutually exclusive groups.

[0160] In some cases, multiple sets of antenna groups (e.g., multiple antenna groupings) may be defined and used to determine settings (e.g., transmit power and / or back-off factors) for multiple transmitters and / or antennas. That is, a UE may be configured with multiple antenna groupings, where each antenna grouping has antenna groups that may be defined differently from the other antenna groupings. For example, with reference to FIG. 7, the first antenna 702a, the third antenna 702c, and the fifth antenna 702e may be antenna modules having antenna arrays configured to transmit in one or more mmWave bands (e.g., from about 24 GHz to 53 GHz or higher). The other antennas 702b, 702d, 702f, and 702g may be configured to transmit in sub-6 GHz bands (e.g., below 6 GHz).

[0161] The first antenna grouping (M1) may include three antenna groups, and the second antenna grouping (M2) may include two antenna groups. The antenna groups of the first antenna grouping (M1) may include a first antenna group (AG1) having all of the sub-6 GHz antennas 702b, 702d, 702f, and 702g and the first antenna 702a, a second antenna group (AG2) having all of the sub-6 GHz antennas 702b, 702d, 702f, and 702g and the third antenna 702c, and a third antenna group (AG3) having all of the sub-6 GHz antennas 702b, 702d, 702f, and 702g and the fifth antenna 702e. In an aspect, the first antenna grouping (M1) may be expressed as follows: AG1: {All sub-6GHz antennas, first mmWave module} AG2: {All sub-6GHz antennas, second mmWave module} AG3: {All sub-6GHz antennas, third mmWave module} The antenna groups of the second antenna grouping (M2) may include a fourth antenna group (AG4) having the second antenna 702b, the fourth antenna 702d, and all of the mmWave antennas 702a, 702c, and 702e, and a fifth antenna group (AG5) having the sixth antenna 702f, the seventh antenna 702g, and all of the mmWave antennas 702a, 702c, and 702e. The second antenna grouping may be expressed as follows: AG4: {First subgroup of sub-6GHz antennas, all mmWave modules} AG5: {Second subgroup of sub-6GHz antennas, all mmWave modules} Here, the first subgroup may include sub-6 GHz antennas (such as the second antenna 702b and the fourth antenna 702d) located on the top of the UE, and the second sub-6 GHz subgroup may include sub-6 GHz antennas (such as the sixth antenna 702f and the seventh antenna 702g) located on the bottom of the UE.

[0162] In some aspects, sub-6 GHz (e.g., frequency range 1 (FR1)) RF exposure may be calculated via measurement, and mmWave (e.g., frequency range 2 (FR2)) RF exposure (for beams in the codebook) may be calculated via simulation (e.g., as described above). In such cases, sub-6 GHz antennas may be grouped into M2 groups (with all mmWave modules in each of the groups), and mmWave antennas are grouped into M1 groups (with all sub-6 GHz antennas in each of the groups), as described above.

[0163] Those skilled in the art will appreciate that groupings M1 and M2 are merely examples for arranging antennas into groups for ease of understanding. Aspects of the present disclosure may also be applied to arranging antennas into additional or alternative groups, such as the groupings described above with respect to assigning antennas to multiple groups. For example, all of either the FR1 radios or the FR2 radios may be assigned to all of the antenna groups, and the other of the FR1 radios or the FR2 radios may be non-uniquely spread among the antenna groups. In one such example, antenna grouping (M3) may include the fourth antenna group AG4 and the fifth antenna group AG5, plus an additional antenna group (AG6) having the second antenna 702b, the sixth antenna 702f, and all of the mmWave antennas 702a, 702c, and 702e. In another such example, the antenna grouping (M4) may include a fourth antenna group AG4, as well as a seventh antenna group (AG7) having the second antenna 702b, the sixth antenna 702f, the seventh antenna 702g, and all of the mmWave antennas 702a, 702c, and 702e.

[0164] In these examples, two or more determinations of time averaging (e.g., at least one for each set, according to one or more back-off values ​​defined for the set) may be performed. Processor 280 may determine to apply a transmit configuration to the antennas based on the results of the two or more determinations. In some embodiments, a minimum value of the transmit power limit across multiple groupings of antennas (e.g., M1 vs. M2, or M1 vs. M3 and / or M4) may be selected and achieved by processor 280 to ensure, for example, overall time-averaged RF exposure compliance.

[0165] In some cases, the UE may access a stored back-off factor and transmit a signal from at least one antenna using a transmit power level based on the back-off factor in accordance with radio frequency exposure requirements, as described herein. The back-off factor may correspond to at least one antenna group of a plurality of antenna groups, where the at least one antenna is in the at least one antenna group.

[0166] Exemplary Selection and Switching Between Sets of Antenna Groups Aspects of the present disclosure relate to selecting a set of antenna groups (also referred to herein as a “grouping”) for operation by a wireless communication device (e.g., UE 120). Operating with a particular set of antenna groups may be beneficial for certain radio transmission scenarios (e.g., by providing higher performance). For example, when operating with the antenna groups (AG1, AG2, and AG3) of the first antenna grouping (M1), each mmW module can obtain up to 100% RF exposure margin in this scenario (depending on how much margin the sub6 antenna consumes), allowing the mmW modules to obtain more combined total RF exposure margin. Therefore, when operating with LTE and Frequency Range 2 (FR2) in NR (e.g., LTE+FR2 link), it may be beneficial to operate according to the M1 grouping. In contrast, when operating only in sub-6 GHz bands (e.g., LTE and Frequency Range 1 (FR1) in NR, such as in an LTE+FR1 link), it may be beneficial to operate, for example, according to M2 grouping (with AG4 and AG5) or one of M3 and M4 groupings.

[0167] Aspects of the present disclosure also relate to switching between sets of antenna groups, such as when a wireless communication device (e.g., UE 120) changes its operating parameters. When switching from one antenna grouping to another (e.g., for performance benefits), RF exposure compliance should ideally be guaranteed because the grouping assumptions may have changed. For example, when switching from the M1 grouping to the M2 grouping (or from the M1 grouping to one of the M3 and M4 groupings), if each mmW module was previously operating with 100% RF exposure margin, the time history for all antenna groups in the M1 grouping may exceed the RF exposure compliance limit when switching to the M2 grouping (e.g., from an LTE+FR2 call to an LTE+FR1 call) or one of the M3 and M4 groupings. Accordingly, aspects of the present disclosure provide one or more criteria for switching between different groupings (referred to herein as "switch criteria") to maximize or at least increase the benefits of switching while simultaneously ensuring RF exposure compliance.

[0168] For example, assume there are a total of B mmW groups in the M1 grouping (with all sub-6 GHz groups added to each of the mmW groups) and A sub-6 GHz groups in the M2 grouping (with all mmW groups added to each of the sub6 groups). In this case, the total RF exposure margin available in the M1 grouping is equal to 100% - (sub6_1 + sub6_2 + ... + sub6_A) - max{mmW_1, mmW_2, ..., mmW_B}, and the total RF exposure margin available in the M2 grouping is equal to 100% - (mmW_1 + mmW_2 + ... + mmW_B) - max{sub6_1, sub6_2, ..., sub6_A}. The switching criteria for changing from M1 grouping to M2 grouping (e.g., handing over an LTE+FR2 call to an LTE+FR1 call) may include the total available margin (TAM) during the M2 grouping being greater than the total available margin during the M1 grouping (TAM, M2>TAM, M1). Similarly, the switching criteria for changing from M2 grouping to M1 grouping (e.g., handing over an LTE+FR1 call to an LTE+FR2 call) may include the total available margin during the M1 grouping being greater than the total available margin during the M2 grouping (TAM, M1>TAM, M2).

[0169] The above example has only two different sets of antenna groups (M1 and M2 groupings). However, this concept and the criteria for switching between antenna groups can be extended to more than two different groupings (e.g., to M3 and M4 as well, or to using M3 and M4 instead of M2 in the above example). In general, the switching criteria for changing from one radio configuration to another may include the total available margin in the new grouping being greater than the total available margin in the current (old) grouping.

[0170] Furthermore, the decision to switch between sets of antenna groups may be based on one or more criteria in addition to the total available margin. For example, in a combined transmission scenario of multiple sub-6 GHz radios and multiple mmW radios, the wireless communication device may use the radio priorities to select operation with a particular set of antenna groups that provides the highest priority radio with the greatest total available margin. In other words, the wireless communication device may select a grouping that divides the antennas associated with the highest priority radio into the largest number of antenna groups.

[0171] 10 , the operations 1000 may further involve the UE selecting a first grouping among the multiple antenna groups based on one or more criteria. In some aspects, the antenna group in block 1002 is in the first grouping, and the back-off factor in block 1002 is among a plurality of stored back-off factors for the first grouping and is associated with the antenna group in the first grouping. In this case, the one or more criteria may include a total RF exposure margin available for different groupings among the multiple antenna groups, including that for the first grouping. In some aspects, the one or more criteria may also include a priority of a radio type.

[0172] According to some aspects, the operations 1000 may further involve the UE selecting a second grouping among the multiple antenna groups based on one or more criteria, accessing another stored back-off factor associated with the antenna group in the second grouping, and transmitting another signal from at least one transmit antenna in the antenna group in the second grouping at another transmit power level based on the other back-off factor in accordance with the RF exposure requirement. In this case, the one or more criteria may include total RF exposure margins available for different groupings among the multiple antenna groups, including those for the first grouping and those for the second grouping. Furthermore, the total RF exposure margin available for the second grouping may be greater than the total RF exposure margin available for the first grouping when selecting the second grouping.

[0173] According to some aspects, the accessing in block 1002 may include accessing a first stored back-off factor associated with a first antenna group in a first grouping among the plurality of antenna groups. In this case, the operations 1000 may further involve the UE accessing a second stored back-off factor associated with a second antenna group in a second grouping among the plurality of antenna groups based on one or more switching criteria.

[0174] In some aspects, a wireless communication device (e.g., a UE) may select a specific antenna grouping, such as M1, M2, or one of several antenna groupings, where all FR2 antennas are assigned to every antenna group and the FR1 antennas are distributed among antenna groups such that at least one of the FR1 antennas is assigned to multiple antenna groups (e.g., selecting between M3 and M4). The wireless communication device may select an antenna grouping for a particular transmission scenario, for example, as described herein with respect to operations 600 for grouping antennas for RF exposure matching. As an example, the wireless communication device may select an antenna grouping for a particular area when the wireless communication device is located in the area. In some cases, the wireless communication device may select an antenna grouping for a particular exposure scenario, such as when the wireless communication device is in close proximity to a user's head, arm, or abdomen. In some cases, the wireless communication device may select an antenna grouping for when several antennas are being used for simultaneous transmission. Additionally, the wireless device may select an antenna grouping based on a combination of these factors, for example, based on a particular region and the total margin available in the groupings that correspond to or can be used within that particular region.

[0175] Exemplary Communication Devices 11 shows a communications device 1100 (e.g., UE 120) that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as those illustrated in FIG. 6 and / or FIG. 10. The communications device 1100 includes a processing system 1102 that may be coupled to a transceiver 1108 (e.g., a transmitter and / or a receiver). The transceiver 1108 is configured to transmit and receive signals for the communications device 1100 via an antenna 1110, such as various signals described herein. The processing system 1102 may be configured to perform processing functions for the communications device 1100, including processing signals received by and / or to be transmitted by the communications device 1100.

[0176] The processing system 1102 includes a processor 1104 coupled to a computer-readable medium / memory 1112 via a bus 1106. In some aspects, the computer-readable medium / memory 1112 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1104, cause the processor 1104 to perform the operations shown in FIG. 6 and / or FIG. 10 or other operations for implementing various techniques described herein for providing RF exposure adaptation. In some aspects, the computer-readable medium / memory 1112 stores code for generating 1114, code for allocating 1116, code for accessing 1118, code for transmitting 1120, code for receiving (or obtaining) 1122, and / or code for determining (e.g., code for generating and / or code for receiving) 1124. In some aspects, the processing system 1102 has circuitry 1126 configured to implement the code stored in the computer-readable medium / memory 1112. In some aspects, the circuit 1126 is coupled to the processor 1104 and / or the computer-readable medium / memory 1112 via the bus 1106. For example, the circuit 1126 includes a circuit for generating 1128, a circuit for allocating 1130, a circuit for accessing 1132, a circuit for transmitting 1134, a circuit for receiving (or obtaining) 1136, and / or a circuit for determining (e.g., a circuit for generating and / or a circuit for receiving) 1138.

[0177] Exemplary Embodiments

[0165] In addition to the various aspects described above, certain combinations of aspects are within the scope of the present disclosure, some of which are described in more detail below.

[0178]

[0166] Aspect 1: A method of wireless communication by a user equipment (UE), comprising accessing a stored back-off factor associated with an antenna group among a plurality of antenna groups, and transmitting a signal from at least one transmitting antenna in the antenna group at a transmit power level based on the back-off factor in accordance with radio frequency (RF) exposure requirements.

[0179]

[0167] Aspect 2: The method described in aspect 1, wherein transmitting a signal at a transmission power level comprises transmitting a signal at a transmission power level based on the sum of the RF exposures for each of the antenna groups being less than or equal to a threshold.

[0180]

[0168] Aspect 3: The method described in aspect 1, wherein transmitting a signal at a transmission power level comprises transmitting a signal at a transmission power level based on the time-averaged sum of RF exposure for each of the antenna groups being less than or equal to a threshold value.

[0181]

[0169] Aspect 4: A method as described in aspect 2 or 3, wherein the back-off factor comprises a plurality of back-off factors, each of which is associated with a distinct antenna group of the plurality of antenna groups such that a distinct back-off factor of the plurality of back-off factors is applied to the sum of the RF exposure for each of the antenna groups.

[0182]

[0170] Aspect 5: A method as described in any of aspects 1 to 4, further comprising determining a time-averaged RF exposure for each of the antenna groups, wherein transmitting a signal at a transmit power level comprises transmitting a signal at a transmit power level based on each of the time-averaged RF exposures being below a threshold.

[0183]

[0171] Aspect 6: The method of aspect 5, wherein determining the time-averaged RF exposure comprises simultaneously determining the time-averaged RF exposure for each of the antenna groups.

[0184]

[0172] Aspect 7: A method described in any of aspects 1 to 6, wherein transmitting a signal at a transmission power level comprises transmitting a signal at a transmission power level based on enforcing RF exposure compliance for one of a plurality of antenna groups having a lower transmission power limit than another of the plurality of antenna groups.

[0185]

[0173] Aspect 8: A method described in any of aspects 1 to 7, wherein at least one of the antenna groups comprises a first antenna configured to transmit in a first mode and a second antenna configured to transmit in a second mode.

[0186]

[0174] Aspect 9: The method of aspect 8, wherein the first mode is a sub-6 GHz band transmission mode and the second mode is a millimeter wave (mmWave) band transmission mode.

[0187]

[0175] Aspect 10: A method described in any of aspects 1 to 9, wherein the multiple antenna groups comprise multiple transmitting antennas, the transmitting antennas comprising one or more first antennas configured to transmit in a first mode and one or more second antennas configured to transmit in a second mode, the one or more first antennas being separately assigned to the antenna groups, and the one or more second antennas being included within each of the antenna groups.

[0188]

[0176] Aspect 11: The method described in aspect 10, wherein transmitting in the first mode involves transmitting at one or more frequencies below 6 GHz, and transmitting in the second mode involves transmitting at one or more frequencies above 6 GHz.

[0189]

[0177] Aspect 12: The method of any one of aspects 1 to 11, wherein the plurality of antenna groups are represented by one or more back-off factors including a back-off factor.

[0190]

[0178] Aspect 13: A method according to any of aspects 1 to 12, further comprising selecting a first grouping among a plurality of antenna groups based on one or more criteria, wherein the antenna group is in the first grouping, and wherein a back-off factor is among a plurality of stored back-off factors for the first grouping and is associated with the antenna group in the first grouping.

[0191]

[0179] Aspect 14: The method described in aspect 13, wherein the one or more criteria comprise a total RF exposure margin available for different groupings among the multiple antenna groups, including that for the first grouping.

[0192]

[0180] Aspect 15: The method described in aspect 13, wherein the one or more criteria comprise a total RF exposure margin available for different groupings among the multiple antenna groups and a priority of radio type.

[0193]

[0181] Aspect 16: The method described in aspect 13, further comprising selecting a second grouping among the multiple antenna groups based on one or more criteria, accessing another stored back-off factor associated with the antenna group in the second grouping, and transmitting another signal from at least one transmitting antenna in the antenna group in the second grouping at another transmit power level based on another back-off factor in accordance with RF exposure requirements.

[0194]

[0182] Aspect 17: The method described in aspect 16, wherein the one or more criteria include a total RF exposure margin available for different groupings among a plurality of antenna groups, including one for a first grouping and one for a second grouping, and the total RF exposure margin available for the second grouping is greater than the total RF exposure margin available for the first grouping when selecting the second grouping.

[0195]

[0183] Aspect 18: A method described in any of aspects 1 to 12, wherein the accessing comprises accessing a first stored back-off factor associated with a first antenna group in a first grouping among the plurality of antenna groups, the method further comprising accessing a second stored back-off factor associated with a second antenna group in a second grouping among the plurality of antenna groups based on one or more switching criteria.

[0196]

[0184] Aspect 19: An apparatus for wireless communication comprising: a memory; a processor coupled to the memory; and a transmitter configured to transmit a signal from at least one transmitting antenna in the antenna group at a transmit power level based on the back-off factor in accordance with radio frequency (RF) exposure requirements, wherein the processor and the memory are configured to access stored back-off factors associated with an antenna group among a plurality of antenna groups.

[0197]

[0185] Aspect 20: The apparatus of aspect 19, wherein the transmitter is configured to transmit a signal at a transmit power level based on the sum of the RF exposures for each of the antenna groups being less than or equal to a threshold.

[0198]

[0186] Aspect 21: The device described in aspect 19, wherein the transmitter is configured to transmit a signal at a transmit power level based on the time-averaged sum of RF exposure for each of the antenna groups being less than or equal to a threshold.

[0199]

[0187] Aspect 22: The apparatus described in aspect 20 or 21, wherein a back-off factor is applied to the RF exposure for each of the antenna groups.

[0200]

[0188] Aspect 23: An apparatus described in any of aspects 19 to 22, wherein the processor and memory are further configured to determine a time-averaged RF exposure for each of the antenna groups, and the transmitter is configured to transmit a signal at a transmit power level based on each of the time-averaged RF exposures being below a threshold.

[0201]

[0189] Aspect 24: The apparatus described in aspect 23, wherein the processor and memory are configured to simultaneously determine the time-averaged RF exposure for each of the antenna groups.

[0202]

[0190] Aspect 25: An apparatus described in any of aspects 19 to 24, wherein the transmitter is configured to transmit a signal at a transmission power level based on enforcing RF exposure compliance for one of a plurality of antenna groups having a lower transmission power limit than another of the plurality of antenna groups.

[0203]

[0191] Aspect 26: An apparatus described in any of aspects 19 to 25, wherein at least one of the antenna groups comprises a first antenna configured to transmit in a first mode and a second antenna configured to transmit in a second mode.

[0204] Aspect 27: The apparatus of aspect 26, wherein the first mode is a sub-6 GHz band transmission mode and the second mode is a millimeter wave (mmWave) band transmission mode.

[0205]

[0193] Aspect 28: An apparatus described in any of aspects 19 to 27, wherein the multiple antenna groups include multiple transmit antennas, the transmit antennas including one or more first antennas configured to transmit in a first mode and one or more second antennas configured to transmit in a second mode, the one or more first antennas being separately assigned to the antenna groups, and the one or more second antennas being included within each of the antenna groups.

[0206]

[0194] Aspect 29: The apparatus of aspect 28, wherein to support a first mode, one or more first antennas are capable of operating at one or more frequencies below 6 GHz, and to support a second mode, one or more second antennas are capable of operating at one or more frequencies above 6 GHz.

[0207]

[0195] Aspect 30: The apparatus of any of aspects 19 to 29, wherein the plurality of antenna groups are represented by one or more back-off factors including a back-off factor.

[0208]

[0196] Aspect 31: An apparatus for wireless communications, comprising: means for accessing a stored back-off factor associated with an antenna group among a plurality of antenna groups; and means for transmitting a signal from at least one transmitting antenna in the antenna group at a transmit power level based on the back-off factor in accordance with radio frequency (RF) exposure requirements.

[0209]

[0197] Aspect 32: An apparatus according to aspect 31, wherein the apparatus comprises means for carrying out any of aspects 1 to 18.

[0210] Aspect 33: A computer-readable medium having stored thereon instructions for carrying out any of aspects 1 to 18.

[0211]

[0199] Aspect 34: A method for grouping antennas, comprising determining a radio frequency (RF) exposure distribution for each transmit antenna configuration for a plurality of transmit antennas, and assigning the plurality of transmit antennas to a plurality of antenna groups based at least in part on the RF exposure distribution.

[0212]

[0200] Aspect 35: The method described in aspect 34, further comprising determining a back-off factor for at least one of a plurality of antenna groups, and transmitting from at least one antenna in at least one of the plurality of antenna groups using a transmission power level based on the back-off factor, wherein the transmitting is performed by a user equipment (UE).

[0213]

[0201] Aspect 36: A method as described in aspect 34 or 35, wherein allocating multiple transmit antennas to multiple antenna groups comprises generating a normalized distribution of the RF exposure distribution, generating a normalized composite map of the normalized distribution for each of the antenna groups, and generating a sum of the normalized composite maps for all of the antenna groups based on a back-off factor associated with each of the antenna groups.

[0214]

[0202] Aspect 37: The method of claim 36, wherein generating a normalized distribution comprises dividing the RF exposure distribution by the maximum RF exposure value for the corresponding transmit antenna configuration, generating a normalized composite map comprises selecting the maximum value of the normalized distribution as the normalized composite map for each of the antenna groups, and generating a sum of the normalized composite maps comprises multiplying the normalized composite map for each antenna group by an associated back-off factor to generate a weighted normalized composite map for each antenna group and adding the weighted normalized composite maps together.

[0215]

[0203] Aspect 38: A method described in aspect 36 or 37, wherein generating a sum of the normalized composite map comprises adjusting at least one of the back-off factors and applying the adjusted at least one of the back-off factors to generating the sum of the normalized composite map until the sum of the normalized composite map is less than or equal to a threshold.

[0216]

[0204] Aspect 39: A method described in any of aspects 36 to 38, wherein allocating multiple transmit antennas to multiple antenna groups comprises determining back-off factors for a first grouping of antenna groups, and if at least one of the back-off factors for the first grouping is less than a threshold, allocating transmit antennas to a second grouping of antenna groups.

[0217]

[0205] Aspect 40: The method described in aspect 39, wherein allocating multiple transmit antennas to multiple antenna groups further comprises determining back-off factors for a second grouping of antenna groups, and if at least one of the back-off factors for the second group is less than a threshold, allocating transmit antennas to a third grouping of antenna groups, wherein the third grouping includes at least two antenna groups having multiple transmit antennas in each of the at least two antenna groups.

[0218]

[0206] Aspect 41: A method according to any one of aspects 36 to 40, wherein the first grouping comprises a separate antenna group for each transmit antenna, and the second grouping comprises at least one antenna group having multiple transmit antennas.

[0219]

[0207] Aspect 42: A method described in any of aspects 34 to 41, wherein at least one of the antenna groups comprises a first antenna configured to transmit in a first mode and a second antenna configured to transmit in a second mode.

[0220] Aspect 43: The method of aspect 42, wherein the first mode is a sub-6 GHz band transmission mode and the second mode is a millimeter wave (mmWave) band transmission mode.

[0221]

[0209] Aspect 44: A method described in aspect 42 or 43, wherein the first antenna has multiple transmit antenna configurations, each of the multiple transmit antenna configurations is associated with one or more bands of the first mode, and the RF exposure distribution comprises a set of RF exposure distributions associated with the multiple transmit antenna configurations of the first antenna.

[0222]

[0210] Example 45: The method of any one of Examples 34 to 44, wherein at least one of the transmitting antennas is part of an antenna module having multiple antennas.

[0223]

[0211] Aspect 46: A method according to any one of aspects 34 to 45, further comprising transmitting a signal by the user equipment at a transmit power level based on forcing RF exposure conformance for at least one of the antenna groups.

[0224]

[0212] Aspect 47: A method described in any of aspects 34 to 46, wherein the allocating comprises assigning each of a plurality of transmitting antennas to one of a plurality of antenna groups based on the RF exposure distribution, such that the transmitting antenna is not in a plurality of antenna groups.

[0225]

[0213] Aspect 48: A method according to any of aspects 34 to 46, wherein the allocating comprises allocating at least one of the transmit antennas to two or more of the plurality of antenna groups based at least in part on the RF exposure distribution.

[0226]

[0214] Aspect 49: A method described in any of aspects 34 to 48, wherein the allocating comprises identifying that at least one of the transmitting antennas does not satisfy a mutually exclusive criterion with at least two of the antenna groups, and allocating at least one of the transmitting antennas to at least two of the antenna groups in response to the identification.

[0227]

[0215] Aspect 50: A method described in any of aspects 34 to 49, wherein the allocating comprises identifying a maximum time-average power limit associated with each of the transmit antennas, and allocating at least one of the transmit antennas to at least two of the antenna groups based at least in part on the maximum time-average power limit associated with at least one of the transmit antennas.

[0228]

[0216] Aspect 51: A method according to any of aspects 34 to 50, wherein the allocating comprises allocating transmitting antennas to a first grouping of antenna groups for a first transmission scenario, and allocating transmitting antennas to a second grouping of antenna groups for a second transmission scenario.

[0229]

[0217] Aspect 52: The method of aspect 51, wherein the first transmission scenario is associated with a first country or region, and the second transmission scenario is associated with a second country or region.

[0230]

[0218] Aspect 53: The method of any of aspects 51 or 52, wherein the first transmission scenario is associated with a first exposure scenario, and the second transmission scenario is associated with a second exposure scenario.

[0231]

[0219] Aspect 54: The method of any one of aspects 51 to 53, wherein the first grouping has a different arrangement of the transmit antennas in the multiple antenna groups than the second grouping.

[0232]

[0220] Aspect 55: The method of any one of aspects 51 to 54, wherein at least one of the transmit antennas is in both the first grouping and the second grouping.

[0233]

[0221] Aspect 56: A method according to any one of aspects 51 to 55, further comprising transmitting from at least one transmit antenna in a first grouping during a first transmission scenario, and transmitting from at least one transmit antenna in a second grouping during a second transmission scenario.

[0234]

[0222] Aspect 57: A method described in any of aspects 34 to 56, wherein allocating comprises allocating all FR2 antennas to all of the antenna groups and distributing the FR1 antennas across the antenna groups such that at least one of the FR1 antennas is in multiple antenna groups.

[0235]

[0223] Aspect 58: An apparatus for grouping antennas, comprising: a memory; and a processor coupled to the memory, wherein the processor and memory are configured to determine a radio frequency (RF) exposure distribution for each transmit antenna configuration for a plurality of transmit antennas; and assign the plurality of transmit antennas to a plurality of antenna groups based at least in part on the RF exposure distribution.

[0236]

[0224] Aspect 59: The apparatus described in aspect 58, wherein the processor and memory are further configured to determine a back-off factor for at least one of a plurality of antenna groups, and transmit from at least one antenna in at least one of the plurality of antenna groups using a transmit power level based on the back-off factor, wherein the transmitting is performed by a user equipment (UE).

[0237]

[0225] Aspect 60: The device described in aspect 58 or 59, wherein the processor and memory are further configured to assign at least one of the transmit antennas to two or more of the plurality of antenna groups based at least in part on the RF exposure distribution.

[0238]

[0226] Aspect 61: An apparatus described in any of aspects 58 to 60, wherein the processor and memory are further configured to identify that at least one of the transmitting antennas does not satisfy a mutually exclusive criterion with at least two of the antenna groups, and in response to the identification, assign at least one of the transmitting antennas to at least two of the antenna groups.

[0239]

[0227] Aspect 62: An apparatus described in any of aspects 58 to 61, wherein the processor and memory are further configured to identify a maximum time-average power limit associated with each of the transmit antennas and assign at least one of the transmit antennas to at least two of the antenna groups based at least in part on the maximum time-average power limit associated with at least one of the transmit antennas.

[0240]

[0228] Aspect 63: An apparatus described in any of aspects 58 to 62, wherein the processor and memory are further configured to assign transmitting antennas to a first grouping of antenna groups for a first transmission scenario, and to assign transmitting antennas to a second grouping of antenna groups for a second transmission scenario.

[0241]

[0229] Aspect 64: An apparatus comprising: a memory having executable instructions; and one or more processors configured to execute the executable instructions and cause the apparatus to perform a method according to any of aspects 1-18 or 34-57.

[0242]

[0230] Embodiment 65: An apparatus, comprising means for carrying out a method according to any of embodiments 1 to 18 or 34 to 57.

[0243]

[0231] Aspect 66: A computer-readable medium comprising executable instructions that, when executed by one or more processors of a device, cause the device to perform a method according to any of aspects 1-18 or 34-57.

[0244] Aspect 67: A computer program product, embodied on a computer-readable storage medium, comprising code for performing the method according to any of aspects 1-18 or 34-57.

[0245] The techniques described herein may be used for various wireless communication technologies, such as NR (e.g., 5G NR), 3GPP® Long Term Evolution (LTE), LTE Advanced (LTE-A), code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single-carrier frequency division multiple access (SC-FDMA), time division synchronous code division multiple access (TD-SCDMA), and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, and the like. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 encompasses the IS-2000, IS-95, and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdMA2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). NR is an emerging wireless communications technology under development.

[0246] In 3GPP, the term "cell" can refer to the coverage area of ​​a Node B (NB) and / or the NB subsystem serving this coverage area, depending on the context in which the term is used. In an NR system, the terms "cell" and BS, next-generation Node B (gNB or gNodeB), access point (AP), distributed unit (DU), carrier, or transmit / receive point (TRP) may be used interchangeably. A BS may provide communication coverage for macrocells, picocells, femtocells, and / or other types of cells. A macrocell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs with service subscriptions. A picocell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femtocell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femtocell (e.g., UEs in a closed subscriber group (CSG), UEs for users at home, etc.). A BS for a macro cell may be referred to as a macro BS, a BS for a pico cell may be referred to as a pico BS, and a BS for a femto cell may be referred to as a femto BS or a home BS.

[0247] A UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smartphone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or equipment, biometric sensor / device, wearable device such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or vehicle sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate over a wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. 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. that may communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be Narrowband IoT (NB-IoT) devices.

[0248] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its coverage area or cell. The scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entities utilize the resources allocated by the scheduling entity. A base station is not the only entity that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and schedule resources for one or more subordinate entities (e.g., one or more other UEs), and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In the example of a mesh network, UEs may communicate directly with each other in addition to communicating with the scheduling entity.

[0249]

[0237] The methods disclosed herein comprise one or more steps or actions for achieving the method. The steps and / or actions of the methods may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be changed without departing from the scope of the claims.

[0250] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to encompass a, b, c, ab, ac, bc, and abc, as well as any combination with multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c).

[0251]

[0239] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, generating, investigating, looking up (e.g., looking up in a table, database, or another data structure), ascertaining, etc. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. Also, "determining" may include resolving, selecting, choosing, establishing, etc.

[0252] The foregoing description is provided to enable any person skilled in the art to practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments. Accordingly, the claims are not limited to the embodiments set forth herein but are to be accorded the full scope consistent with the claim language, wherein reference to an element in the singular does not mean "one and only one," unless expressly stated otherwise, but rather "one or more." Unless expressly stated otherwise, the term "some" refers to one or more. All structural and functional equivalents of the elements of the various embodiments described throughout this disclosure that are known or later become known to those skilled in the art are expressly incorporated herein by reference and are encompassed by the claims. Moreover, nothing disclosed herein is made public, regardless of whether such disclosure is expressly recited in the claims. No claim element shall be construed under the provisions of 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase "means for," or, in the case of a method claim, unless the element is recited using the phrase "step for."

[0253] The various operations of the methods described above may be performed by any suitable means capable of performing the corresponding functions. These means may include various hardware and / or software components and / or modules, including, but not limited to, circuits, application specific integrated circuits (ASICs), or processors. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering.

[0254] The various example logic blocks, modules, and circuits described in connection with this disclosure may be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0255]

[0243] When implemented in hardware, an exemplary hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. The bus may include any number of interconnected buses and bridges, depending on the particular application and overall design constraints of the processing system. The bus may link various circuits together, including processors, machine-readable media, and bus interfaces. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement signal processing functions of the physical (PHY) layer. In the case of a UE (see FIG. 1), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, etc., which are well known in the art and therefore will not be described further. The processor may be implemented using one or more general-purpose and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits capable of executing software. Those skilled in the art will recognize how best to implement the described functionality for a processing system depending on the particular application and the overall design constraints imposed on the overall system.

[0256]

[0244] If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media, including any medium that enables transfer of a computer program from one place to another. A processor may be responsible for managing the bus and for overall processing, including the execution of software modules stored on the machine-readable storage medium. An exemplary computer-readable storage medium may be coupled to the processor such that the processor can read information from and write information to the storage medium. Alternatively, the storage medium may be integral to the processor. For example, the machine-readable medium may include a transmission line, a carrier wave modulated by data, and / or a computer-readable storage medium storing instructions separate from the wireless node, all of which may be accessed by the processor through a bus interface. Alternatively, or in addition, the machine-readable medium, or any portion thereof, may be integrated into the processor, such as may be a cache and / or general-purpose register file. Examples of machine-readable storage media may include, by way of example, RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable medium may be embodied in a computer program product.

[0257] A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. A computer-readable medium may comprise several software modules. A software module contains instructions that, when executed by a device such as a processor, cause a processing system to perform various functions. A software module may include a transmitting module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. As an example, a software module may be loaded into RAM from a hard drive when a trigger event occurs. During execution of a software module, a processor may load some of the instructions into a cache to increase access speed. One or more cache lines may then be loaded into a general-purpose register file for execution by the processor. When referring below to the functionality of a software module, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

[0258]

[0246] Also, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of medium. As used herein, disk and disc include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy discs, and Blu-ray discs, where disks typically reproduce data magnetically and discs reproduce data optically with lasers. Thus, in some aspects computer-readable medium may comprise non-transitory computer-readable medium (e.g., tangible media). Further, in other aspects computer-readable medium may comprise transitory computer-readable medium (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

[0259]

[0247] Accordingly, some aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having stored thereon (and / or encoded thereon) instructions executable by one or more processors to perform the operations described herein, e.g., instructions for performing the operations described herein and illustrated in Figures 6 and / or 10.

[0260]

[0248] Furthermore, it should be appreciated that modules and / or other suitable means for implementing the methods and techniques described herein may be downloaded and / or otherwise obtained by a user terminal and / or base station, where applicable. For example, such a device may be coupled to a server to facilitate the transfer of means for implementing the methods described herein. Alternatively, the various methods described herein may be provided via storage means (e.g., RAM, ROM, or a physical storage medium such as a compact disc (CD) or floppy disk, etc.), and thus the user terminal and / or base station may obtain the various methods upon coupling or providing storage means to the device. Furthermore, any other suitable technique for providing the methods and techniques described herein to a device may be utilized.

[0261]

[0249] It is to be understood that the claims are not limited to the precise configuration and components shown above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims. The inventions described in the claims of the present application as originally filed are set forth below. [C1] 1. A method for grouping antennas, comprising: determining a radio frequency (RF) exposure distribution for each transmit antenna configuration for a plurality of transmit antennas; assigning the plurality of transmit antennas to a plurality of antenna groups based at least in part on the RF exposure distribution; A method for providing [C2] determining a back-off factor for at least one of the plurality of antenna groups; transmitting from at least one antenna in the at least one of the plurality of antenna groups using a transmit power level based on the back-off factor, wherein the transmitting is performed by a user equipment (UE). The method of C1, further comprising: [C3] Allocating the plurality of transmit antennas to the plurality of antenna groups includes: generating a normalized distribution of said RF exposure distribution; generating a normalized composite map of the normalized distributions for each of the antenna groups; generating the normalized combining map sum for all of the antenna groups based on a back-off factor associated with each of the antenna groups; The method of C1, comprising: [C4] generating the normalized distribution comprises dividing the RF exposure distribution by a maximum RF exposure value for a corresponding transmit antenna configuration; generating the normalized composite map comprises selecting a maximum value of the normalized distribution as the normalized composite map for each of the antenna groups; Generating the sum of the normalized composite map comprises: multiplying the associated back-off factor by the normalized combining map for each antenna group to generate a weighted normalized combining map for each antenna group; adding said weighted normalized composite maps together; and The method of C3, comprising: [C5] The method of C3, wherein generating the sum of the normalized composite map comprises adjusting at least one of the back-off factors and applying the adjusted at least one of the back-off factors to generating the sum of the normalized composite map until the sum of the normalized composite map is less than or equal to a threshold. [C6] Allocating the plurality of transmit antennas to the plurality of antenna groups includes: determining the back-off factors for a first grouping of the antenna groups; assigning the transmit antennas to a second one of the antenna groups if at least one of the back-off factors for the first one is less than a threshold; The method of C3, comprising: [C7] Allocating the plurality of transmit antennas to the plurality of antenna groups includes: determining the back-off factors for the second grouping of antenna groups; assigning the transmit antennas to a third grouping of the antenna groups if at least one of the back-off factors for the second grouping is less than the threshold, wherein the third grouping includes the at least two antenna groups having multiple transmit antennas in each of the at least two antenna groups; The method of C6, further comprising: [C8] the first grouping comprises a separate antenna group for each transmit antenna; the second grouping comprises at least one antenna group having a plurality of transmit antennas; The method described in C6. [C9] The method of C1, wherein at least one of the antenna groups comprises a first antenna configured to transmit in a first mode and a second antenna configured to transmit in a second mode. [C10] The method of C9, wherein the first mode is a sub-6 GHz band transmission mode and the second mode is a millimeter wave (mmWave) band transmission mode. [C11] The method of C9, wherein the first antenna has a plurality of transmit antenna configurations, each of the plurality of transmit antenna configurations associated with one or more bands of the first mode, and the RF exposure distribution comprises a set of RF exposure distributions associated with the plurality of transmit antenna configurations of the first antenna. [C12] The method of C1, wherein at least one of the transmit antennas is part of an antenna module having multiple antennas. [C13] The method of C1, further comprising transmitting a signal by user equipment at a transmit power level based on enforcing RF exposure conformance for at least one of the antenna groups. [C14] The method of claim 1, wherein the assigning comprises assigning each of the plurality of transmit antennas to one of the plurality of antenna groups based on the RF exposure distribution, such that a transmit antenna is not in a plurality of antenna groups. [C15] The method of C1, wherein the allocating comprises allocating at least one of the transmit antennas to two or more of the plurality of antenna groups based at least in part on the RF exposure distribution. [C16] The assigning step comprises: identifying at least one of the transmit antennas not meeting a mutually exclusive criterion with at least two of the antenna groups; assigning the at least one of the transmit antennas to the at least two of the antenna groups in response to the identifying; The method of C1, comprising: [C17] The assigning step comprises: identifying a maximum time-averaged power limit associated with each of the transmit antennas; assigning at least one of the transmit antennas to at least two of the antenna groups based at least in part on the maximum time-averaged power limit associated with at least one of the transmit antennas; The method of C1, comprising: [C18] The assigning step comprises: assigning the transmit antennas to a first grouping of the antenna groups for a first transmission scenario; assigning the transmit antennas to a second grouping of the antenna groups for a second transmission scenario; The method of C1, comprising: [C19] The method of C18, wherein the first transmission scenario is associated with a first country or region and the second transmission scenario is associated with a second country or region. [C20] The method of C18, wherein the first transmission scenario is associated with a first exposure scenario and the second transmission scenario is associated with a second exposure scenario. [C21] The method of C18, wherein the first grouping has a different arrangement of transmit antennas in the plurality of antenna groups than the second grouping. [C22] The method of C18, wherein at least one of the transmit antennas is in both the first grouping and the second grouping. [C23] transmitting from at least one transmit antenna in the first grouping during the first transmission scenario; transmitting from at least one transmit antenna in the second grouping during the second transmission scenario; and The method of C18, further comprising: [C24] The method of C1, wherein the allocating comprises: allocating all FR2 antennas to all of the antenna groups; and distributing the FR1 antennas across the antenna groups such that at least one of the FR1 antennas is in more than one of the antenna groups. [C25] 1. An apparatus for grouping antennas, comprising: Memory and a processor coupled to the memory; wherein the processor and the memory determining a radio frequency (RF) exposure distribution for each transmit antenna configuration for a plurality of transmit antennas; assigning the plurality of transmit antennas to a plurality of antenna groups based at least in part on the RF exposure distribution; An apparatus configured to: [C26] The processor and the memory determining a back-off factor for at least one of the plurality of antenna groups; transmitting from at least one antenna in the at least one of the plurality of antenna groups using a transmit power level based on the back-off factor, wherein the transmitting is performed by a user equipment (UE). The apparatus of C25, further configured to: [C27] 26. The apparatus of claim 25, wherein the processor and the memory are further configured to assign at least one of the transmit antennas to two or more of the plurality of antenna groups based at least in part on the RF exposure distribution. [C28] The processor and the memory identifying at least one of the transmit antennas not meeting a mutually exclusive criterion with at least two of the antenna groups; assigning the at least one of the transmit antennas to the at least two of the antenna groups in response to the identifying; The apparatus of C25, further configured to: [C29] The processor and the memory identifying a maximum time-averaged power limit associated with each of the transmit antennas; assigning at least one of the transmit antennas to at least two of the antenna groups based at least in part on the maximum time-averaged power limit associated with at least one of the transmit antennas; The apparatus of C25, further configured to: [C30] The processor and the memory assigning the transmit antennas to a first grouping of the antenna groups for a first transmission scenario; assigning the transmit antennas to a second grouping of the antenna groups for a second transmission scenario; The apparatus of C25, further configured to:

Claims

1. 1. A method for grouping antennas, comprising: determining a radio frequency (RF) exposure value for each transmit antenna configuration for the plurality of transmit antennas; assigning the plurality of transmit antennas to a plurality of antenna groups based at least in part on the RF exposure, wherein the plurality of transmit antennas are assigned to the plurality of antenna groups such that the plurality of antenna groups are mutually exclusive with respect to the RF exposure; and said allocating comprises: identifying a maximum time-averaged power limit associated with each of the transmit antennas; assigning at least one of the transmit antennas to at least two of the antenna groups based at least in part on the maximum time-averaged power limit associated with at least one of the transmit antennas; A method for providing

2. determining a back-off factor for at least one of the plurality of antenna groups; transmitting from at least one antenna in the at least one of the plurality of antenna groups using a transmit power level based on the back-off factor, wherein the transmitting is performed by a user equipment (UE). The method of claim 1 further comprising:

3. Allocating the plurality of transmit antennas to the plurality of antenna groups includes: generating a normalized distribution of the RF exposure values; generating a normalized composite map of the normalized distributions for each of the antenna groups; generating the normalized combining map sum for all of the antenna groups based on a back-off factor associated with each of the antenna groups; The method of claim 1 , comprising:

4. generating the normalized distribution comprises dividing the RF exposure values ​​by a maximum RF exposure value for a corresponding transmit antenna configuration; generating the normalized composite map comprises selecting a maximum value of the normalized distribution as the normalized composite map for each of the antenna groups; Generating the sum of the normalized composite map comprises: multiplying the associated back-off factor by the normalized combining map for each antenna group to generate a weighted normalized combining map for each antenna group; adding said weighted normalized composite maps together; and or 4. The method of claim 3, wherein generating the sum of the normalized composite map comprises adjusting at least one of the back-off factors and applying the adjusted at least one of the back-off factors to generating the sum of the normalized composite map until the sum of the normalized composite map is less than or equal to a threshold.

5. Allocating the plurality of transmit antennas to the plurality of antenna groups includes: determining the back-off factors for a first grouping of the antenna groups; assigning the transmit antennas to a second one of the antenna groups if at least one of the back-off factors for the first grouping is less than a threshold; and The method of claim 3 comprising:

6. Allocating the plurality of transmit antennas to the plurality of antenna groups includes: determining the back-off factors for the second grouping of antenna groups; assigning the transmit antennas to a third grouping of the antenna groups if at least one of the back-off factors for the second grouping is less than the threshold, wherein the third grouping includes the at least two antenna groups having multiple transmit antennas in each of the at least two antenna groups; and / or wherein the first grouping comprises a separate antenna group for each transmit antenna, and the second grouping comprises at least one antenna group having multiple transmit antennas. The method of claim 5 further comprising:

7. 10. The method of claim 1, wherein at least one of the antenna groups comprises a first antenna configured to transmit in a first mode and a second antenna configured to transmit in a second mode.

8. 8. The method of claim 7, wherein the first mode is a sub-6 GHz band transmission mode and the second mode is a millimeter-wave (mmWave) band transmission mode, and / or the first antenna has multiple transmit antenna configurations, each of the multiple transmit antenna configurations associated with one or more bands of the first mode, and the RF exposure values ​​comprise a set of RF exposure values ​​associated with the multiple transmit antenna configurations of the first antenna.

9. The method of claim 1 , wherein the allocating comprises allocating at least one of the transmit antennas to two or more of the plurality of antenna groups based at least in part on the RF exposure value.

10. The assigning step comprises: identifying at least one of the transmit antennas not meeting a mutually exclusive criterion with at least two of the antenna groups; assigning the at least one of the transmit antennas to the at least two of the antenna groups in response to the identifying; and The method of claim 1 , comprising:

11. The assigning step comprises: assigning the transmit antennas to a first grouping of the antenna groups for a first transmission scenario; assigning the transmit antennas to a second grouping of the antenna groups for a second transmission scenario; and The method of claim 1 , comprising:

12. 12. The method of claim 11, wherein the first transmission scenario is associated with a first country or region and the second transmission scenario is associated with a second country or region, or the first transmission scenario is associated with a first exposure scenario and the second transmission scenario is associated with a second exposure scenario, or the first grouping has a different arrangement of transmit antennas in the plurality of antenna groups than the second grouping, or at least one of the transmit antennas is in both the first grouping and the second grouping.

13. transmitting from at least one transmit antenna in the first grouping during the first transmission scenario; transmitting from at least one transmit antenna in the second grouping during the second transmission scenario; and The method of claim 11 further comprising:

14. 2. The method of claim 1 , wherein the assigning comprises assigning all FR2 antennas to all of the antenna groups; and distributing the FR1 antennas across the antenna groups such that at least one of the FR1 antennas is in more than one of the antenna groups.

15. 1. An apparatus for grouping antennas, comprising: Memory and a processor coupled to the memory; 15. An apparatus comprising: a processor and a memory configured to perform a method according to any one of claims 1 to 14.

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