Compressed Radio Frequency Exposure Map

Abstract

Techniques and apparatus are described for generating a compressed radio frequency (RF) exposure map and using such compressed RF exposure map to determine a transmit power that meets RF exposure compliance limits. An exemplary method generally includes obtaining a first RF exposure map associated with at least one antenna of a wireless device and converting the first RF exposure map to a second RF exposure map. The second RF exposure map is compressed relative to the first RF exposure map. Another exemplary method includes accessing an RF exposure map associated with at least one antenna of the wireless device. The RF exposure map includes a representation of maximum RF exposure for a region of the RF exposure map. The method also includes transmitting a signal from the antenna at a transmit power that complies with the RF exposure limits, determined based on the RF exposure map.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS)

[0001] This application claims priority to U.S. Provisional Patent Application No. 18 / 544,768, filed December 19, 2023, which claims the benefit of U.S. Patent Application No. 63 / 476,615, filed December 21, 2022, the entire contents of both applications being incorporated herein by reference for all applicable purposes.

[0002] introduction Field of Disclosure Aspects of the present disclosure relate to wireless communications, and more particularly, to radio frequency (RF) exposure compliance. [Background technology]

[0003] 2. Description of Related Art

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

[0004]

[0004] The systems, methods, and devices of the present disclosure each have several aspects, no one aspect of which is solely responsible for its desirable attributes. Without limiting the scope of the present disclosure as expressed by the claims that follow, several features will now be briefly described. After considering this description, and particularly after reading the section entitled "Detailed Description of the Invention," one will understand how the features of the present disclosure provide advantages, including improved wireless communication performance.

[0005] Certain aspects of the subject matter described in this disclosure may be implemented in a method for generating a radio frequency (RF) exposure map. The method generally includes obtaining a first RF exposure map associated with at least one antenna of a wireless device. The method also includes converting the first RF exposure map to a second RF exposure map. The second RF exposure map is compressed compared to the first RF exposure map.

[0006] Certain aspects of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication. The apparatus generally includes one or more memories that collectively store executable instructions and one or more processors coupled to the one or more memories. The one or more processors are collectively configured to execute the executable instructions, which cause the apparatus to obtain a first RF exposure map associated with at least one antenna of a wireless device and convert the first RF exposure map into a second RF exposure map. The second RF exposure map is compressed compared to the first RF exposure map.

[0007]

[0007] Certain aspects of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication. The apparatus generally includes means for acquiring a first RF exposure map associated with at least one antenna of a wireless device. The apparatus also includes means for converting the first RF exposure map into a second RF exposure map. The second RF exposure map is compressed compared to the first RF exposure map.

[0008]

[0008] Certain aspects of the subject matter described in this disclosure may be implemented in a computer-readable medium. The computer-readable medium has instructions stored thereon that, when executed by an apparatus, cause the apparatus to perform operations. The operations generally include obtaining a first RF exposure map associated with at least one antenna of a wireless device. The operations also include converting the first RF exposure map to a second RF exposure map. The second RF exposure map is compressed compared to the first RF exposure map.

[0009] Certain aspects of the subject matter described in this disclosure may be implemented in a method for wireless communication by a wireless device. The method generally includes accessing a radio frequency (RF) exposure map associated with at least one antenna of the wireless device. The RF exposure map includes a representation of maximum RF exposure for a region of the RF exposure map. The method also includes transmitting a signal from the at least one antenna at a transmit power that complies with RF exposure limits, determined at least in part based on the RF exposure map.

[0010] Certain aspects of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication. The apparatus generally includes one or more memories that collectively store executable instructions and one or more processors coupled to the one or more memories. The one or more processors are collectively configured to execute the executable instructions, which cause the apparatus to access a radio frequency (RF) exposure map associated with at least one antenna of the apparatus. The RF exposure map includes a representation of maximum RF exposure for a region of the RF exposure map. The one or more processors are also collectively configured to execute the executable instructions, which cause the apparatus to transmit a signal from the at least one antenna at a transmit power that complies with RF exposure limits determined at least in part based on the RF exposure map.

[0011] Certain aspects of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication. The apparatus generally includes means for accessing a radio frequency (RF) exposure map associated with at least one antenna of the apparatus. The RF exposure map includes a representation of maximum RF exposure for a region of the RF exposure map. The apparatus also includes means for transmitting a signal from the at least one antenna at a transmit power that complies with RF exposure limits, determined at least in part based on the RF exposure map.

[0012] Certain aspects of the subject matter described in this disclosure may be implemented in a computer-readable medium. The computer-readable medium has instructions stored thereon that, when executed by a device, cause the device to perform operations. The operations generally include accessing a radio frequency (RF) exposure map associated with at least one antenna of the device. The RF exposure map includes a representation of maximum RF exposure for a region of the RF exposure map. The operations also include transmitting a signal from the at least one antenna at a transmit power that complies with RF exposure limits, determined at least in part based on the RF exposure map.

[0013]

[0013] Other aspects provide an apparatus operable, configured, or otherwise adapted to perform any one or more of the aforementioned methods and / or methods described elsewhere herein; a non-transitory computer-readable medium comprising instructions that, when executed by a processor of the apparatus, cause the apparatus to perform the aforementioned methods and methods described elsewhere herein; a computer program product embodied on a computer-readable storage medium comprising code for performing the aforementioned methods and methods described elsewhere herein; and / or means for performing the aforementioned methods and methods described elsewhere herein. By way of example, the apparatus may include a processing system, a device having a processing system, or processing systems cooperating over one or more networks.

[0014] 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. [Brief explanation of the drawings]

[0015]

[0015] So that the above-mentioned features of the present disclosure may 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. It should be noted, however, that the accompanying drawings illustrate only certain exemplary embodiments of the present disclosure, and therefore should not be considered as limiting the scope of the present disclosure, since the description may admit of other equally effective embodiments. [Figure 1]

[0016] FIG. 1 is a block diagram conceptually illustrating an example wireless communication network. [Figure 2]

[0017] FIG. 1 is a block diagram conceptually illustrating an exemplary base station (BS) and user equipment (UE) design. [Figure 3]

[0018] 1 is a block diagram of an exemplary radio frequency (RF) transceiver. [Figure 4]

[0019] 4A-4C are graphs illustrating examples of transmit power over time in compliance with time-averaged RF exposure limits. [Figure 5]

[0020] FIG. 1 illustrates an exemplary system for measuring RF exposure values ​​or distributions. [Figure 6]

[0021] FIG. 10 is a flow diagram illustrating example operations for generating an RF exposure map according to an aspect of the present disclosure. [Figure 7]

[0022] 10A-10C illustrate a progression of generating an RF exposure map from one or more RF distributions, according to an aspect of the present disclosure. [Figure 8]

[0023] FIG. 10 illustrates eight normalized composite maps per antenna being added together to obtain a total exposure map, according to an aspect of the present disclosure. [Figure 9]

[0024] 1 illustrates an example total exposure map and an updated version of the total exposure map with compliance locations set to specific values, according to an aspect of the present disclosure. [Figure 10]

[0025] 10 illustrates an example of identifying non-compliant regions until all of the non-compliant areas are covered with identified regions, according to an aspect of the present disclosure. [Figure 11]

[0026] 10 illustrates an example of a subset of non-compliant regions selected for a compressed RF exposure map, according to an aspect of the present disclosure. [Figure 12]

[0027] 1 illustrates an example of a composite map and corresponding subset of non-compliant regions, according to certain aspects of the present disclosure. [Figure 13]

[0028] 10 illustrates an example table of maximum RF exposure values ​​per region associated with a particular map, according to an aspect of the present disclosure. [Figure 14]

[0029] FIG. 10 is a flow diagram illustrating in further detail an example operation for generating an RF exposure map according to an aspect of the present disclosure. [Figure 15]

[0030] 10 is an exemplary plot illustrating the average back-off difference in decibels for different ON / OFF combinations of antennas across different test cases, in accordance with certain aspects of the present disclosure. [Figure 16]

[0031] FIG. 10 illustrates an RF exposure map segmented into multiple regions, according to an aspect of the present disclosure. [Figure 17]

[0032] FIG. 10 is a flow diagram illustrating example operations for generating an RF exposure map according to an aspect of the present disclosure. [Figure 18]

[0033] FIG. 10 is a flow diagram illustrating example operations for wireless communication by a wireless device according to an aspect of the present disclosure. [Figure 19]

[0034] 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.

[0016]

[0035] For ease of understanding, the same reference numbers have been used, where possible, to designate identical elements common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. DETAILED DESCRIPTION OF THE INVENTION

[0017]

[0036] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for generating and / or using compressed radio frequency (RF) exposure maps associated with wireless devices.

[0018]

[0037] In some cases, a wireless communication device may evaluate RF exposure compliance using a two-dimensional RF exposure distribution (e.g., a specific absorption rate (SAR) distribution and / or a power density (PD) distribution). The wireless device may perform SAR and PD assessments over a given time window using the RF exposure distribution to determine the maximum allowable transmit power. The RF exposure distribution may represent the maximum RF exposure exhibited by one or more antennas of the wireless device. In some cases, the RF exposure distribution may be a look-up table of maximum RF exposure exhibited by antennas transmitting in various frequency bands. Each of the maximum RF exposures may correspond to a peak RF exposure across all of the surface of the wireless device, with no distinction as to where the RF exposure is emitting from the wireless device. While aspects described herein refer to two-dimensional (2D) distributions, it will be understood that the described operations and configurations may also apply to three-dimensional maps or distributions.

[0019]

[0038] Aspects of the present disclosure provide apparatus and methods for generating and / or using a compressed RF exposure map, which may represent the maximum RF exposure exhibited in a particular region of a wireless device for a certain radio combination. The RF exposure map may be reduced to the maximum RF exposure in a region across the wireless device, thereby allowing the wireless device to assess RF exposure compliance across the region identified for the RF exposure map. In some aspects, the compressed RF exposure map may represent RF exposure in terms of SAR and / or PD.

[0020]

[0039] The apparatus and methods for generating and using compressed RF exposure maps described herein may facilitate improved wireless communication performance (e.g., improved signal quality at the receiver, lower latency, higher throughput, etc.) The apparatus and methods for generating and using compressed RF exposure maps described herein may also enable improved processing performance, for example, by reducing the memory size used by the compressed RF exposure map and / or reducing the number of calculations used to perform RF exposure assessments to meet time-averaged RF exposure compliance during simultaneous transmission scenarios.

[0021]

[0040] As used herein, radio may refer to one or more active bands, transceivers, and / or radio access technologies (RATs) used for wireless communications (e.g., 2G or 3G such as code division multiple access (CDMA), 4G such as Long Term Evolution (LTE), 5G New Radio (NR), IEEE 802.11, Bluetooth, non-terrestrial network (NTN) communications, etc.). For example, in the case of uplink carrier aggregation in LTE and / or NR, each active component carrier used for wireless communications may be treated as a separate radio. Similarly, multi-band transmissions for IEEE 802.11 communications may be treated as separate radios for each band (e.g., 2.4 gigahertz (GHz), 5 GHz, or 6 GHz).

[0022]

[0041] The following description provides examples of RF exposure compliance in communication systems 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 described elements without departing from the scope of the present disclosure. Various embodiments may omit, substitute, or add various procedures or components as appropriate. For example, the 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 embodiments may be combined in some other embodiments. For example, an apparatus may be implemented or a method may be practiced using any number of aspects described herein. Additionally, the scope of the present disclosure is intended to encompass apparatuses or methods practiced using other structure, functions, or structure and functions in addition to or other than the various aspects of the present disclosure described herein. It should be understood that any aspect of the present 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.

[0023]

[0042] Generally, 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 or multiple RATs in a given geographic area to avoid interference between wireless networks of different RATs.

[0024]

[0043] 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 and / or to wireless technologies such as 802.11, 802.15, NTN communications, etc.

[0025]

[0044] NR access may support various wireless communication services, such as enhanced mobile broadband (eMBB), which targets wide bandwidths (e.g., 80 megahertz (MHz) or greater); millimeter wave (mmWave), which targets high carrier frequencies (e.g., 24 GHz to 53 GHz or greater); massive machine type communications (mMTC), 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. In addition, these services may coexist in the same subframe. NR supports beamforming, and beam directions may be dynamically configured. Multiple-input, multiple-output (MIMO) transmission using precoding is supported, and multi-layer transmission may also be supported. Aggregation of multiple cells may be supported.

[0026] Exemplary Wireless Communication Networks and Devices

[0045] 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. As shown in FIG. 1, a UE 120a includes an RF exposure manager 122 that ensures RF exposure compliance using a compressed RF exposure map according to aspects of the present disclosure.

[0027]

[0046] As shown in FIG. 1, wireless communication network 100 may include several BSs 110a-110z (each also referred to herein individually as BS 110 or collectively as BSs 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 stationary or may move according to the location of a mobile BS. In some examples, BSs 110 may be interconnected via various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.) using any suitable transport network and / or to one or more other BSs or network nodes (not shown) in wireless communication network 100. In the example shown in FIG. 1, BSs 110a, 110b, and 110c may be macro BSs of macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS of pico cell 102x. BS 110y and BS 110z may be femto BSs in femto cells 102y and 102z, respectively. A BS may support one or multiple cells.

[0028]

[0047] The BS 110 communicates with UEs 120a through 120y (each also referred to herein individually as a UE 120 or collectively as a UE 120) within 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 a relay station (e.g., relay station 110r), which may also be referred to as a relay, receive transmissions of data and / or other information from an upstream station (e.g., the BS 110a or the UE 120r), forward transmissions of data and / or other information to a downstream station (e.g., the UE 120 or the BS 110), or relay transmissions between the UEs 120 to facilitate communication between the devices.

[0029]

[0048] A network controller 130 may communicate with the set of BSs 110 and provide coordination and control for these BSs 110 (e.g., via a backhaul). In some cases, the network controller 130 may include, for example, a centralized unit (CU) and / or a distributed unit (DU) in a 5G NR system. In some aspects, 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.

[0030]

[0049] 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.

[0031]

[0050] At the BS 110a, the transmit processor 220 may receive data from a 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 automatic repeat request (HARQ) 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 a PDSCH, a physical uplink shared channel (PUSCH), or a physical sidelink shared channel (PSSCH).

[0032]

[0051] 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 may provide output symbol streams to modulators (MODs) within the transceivers 232a through 232t. Each modulator within transceiver 232a through 232t may process a respective output symbol stream (e.g., for orthogonal frequency division multiplexing (OFDM), etc.) to obtain an output sample stream. Each transceiver 232a through 232t may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. The downlink signals from transceivers 232a through 232t may be transmitted via antennas 234a through 234t, respectively.

[0033]

[0052] At UE 120a, antennas 252a through 252r may receive downlink signals from BS 110a and may provide received signals to transceivers 254a through 254r, respectively. Transceivers 254a through 254r may condition (e.g., filter, amplify, downconvert, and digitize) their respective received signals to obtain input samples. Each demodulator (DEMOD) in transceivers 232a through 232t 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 in transceivers 254a through 254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120a to a data sink 260, and provide decoded control information to a controller / processor 280.

[0034]

[0053] On the uplink, at the UE 120a, a transmit processor 264 may receive and process data from a data source 262 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 280 (e.g., for a 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 the transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators (MODs) in transceivers 254a through 254r (e.g., for single-carrier frequency division multiplexing (SC-FDM)), and transmitted to the BS 110a. At BS 110a, the uplink signal from UE 120a may be received by antenna 234, processed by a demodulator within transceiver 232a-232t, 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 UE 120a. Receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to controller / processor 240.

[0035]

[0054] 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.

[0036]

[0055] Antenna 252, processors 266, 258, 264, and / or controller / processor 280 of UE 120a and / or antenna 234, processors 220, 230, 238, and / or controller / processor 240 of BS 110a may be used to implement various techniques and methods described herein. As shown in FIG. 2, controller / processor 280 of UE 120a includes RF exposure manager 281, which represents RF exposure manager 122, in accordance with aspects described herein. While shown in a controller / processor, other components of UE 120a and BS 110a may be used to implement operations described herein.

[0037]

[0056] NR may utilize OFDM with a cyclic prefix (CP) on the uplink and downlink. NR may support half-duplex operation using time division duplexing (TDD). OFDM and SC-FDM partition the system bandwidth into multiple orthogonal subcarriers, which are commonly referred to as tones, bins, etc. 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).

[0038]

[0057] 1 and 2 as communicating with a BS and / or within a network, the UE 120a may be configured to communicate / transmit directly with another UE 120 or another wireless device without relaying the communication through a network. In some aspects, the BS 110a shown in FIG. 2 and described above is an example of another UE 120.

[0039] Exemplary RF Transceiver

[0058] 3 is a block diagram of an example RF transceiver circuit 300 according to an aspect 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, these 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.

[0040]

[0059] The TX path 302, which receives an in-phase (I) or quadrature (Q) baseband analog signal from a digital-to-analog converter (DAC) 310, 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 within one or more radio frequency integrated circuits (RFICs). The PA 318 may be external to the RFIC in some implementations.

[0041]

[0060] 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 translate the baseband signal of interest to a different frequency (e.g., upconvert from baseband to radio frequency). This frequency translation 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. Because the beat frequency is generally in the RF range, the signal output by the mixer 314 is generally an RF signal and can be amplified by the DA 316 and / or the PA 318 before being transmitted by the antenna 306. Although one mixer 314 is shown, several mixers can 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.

[0042]

[0061] 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 RFICs that include the TX path components. RF signals received via the antenna 306 are amplified by the LNA 324, and the mixer 326 may mix the amplified RF signal with a receive local oscillator (LO) signal to translate (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 to digital I or Q signals by an analog-to-digital converter (ADC) 330 for digital signal processing.

[0043]

[0062] 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 and 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 and may be buffered or amplified by an amplifier 334 before being mixed with the RF signal in the mixer 326.

[0044]

[0063] A controller 336 may direct operation of the RF transceiver circuitry 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 circuitry 300. The controller 336 and / or the memory 338 may include control logic. In some cases, the controller 336 may determine the transmit power applied to the TX path 302 (e.g., a level of gain applied to the BBF 312, the DA 316, and / or the PA 318) that complies with RF exposure limits defined by country-specific regulations and / or international standards, as further described herein.

[0045] Exemplary RF Exposure Compliance

[0064] RF exposure can be expressed in units of Specific Absorption Rate (SAR), which measures energy absorption per unit mass by human tissue and can have units of watts per kilogram (W / kg). RF exposure also measures energy absorption per unit area and can be expressed in units of milliwatts per square centimeter (mW / cm). 2 The power density (PD) may have units of 1 / 2 GHz. In some cases, maximum permissible exposure (MPE) limits may be imposed in PD units for wireless devices using transmission frequencies above 6 GHz. MPE limits are based on regulatory standards for area-based exposure, e.g., watts per square meter (W / m), averaged over a defined area and time-averaged over a frequency-dependent time window to prevent human exposure hazards represented by tissue temperature changes. 2 ) is the energy density limit, defined as the number X of

[0046]

[0065] SAR can be used to assess RF exposure for transmission frequencies below 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, NTN, etc. PD can be used to assess RF exposure for transmission frequencies above 6 GHz, which covers wireless communication technologies such as IEEE 802.11ad, 802.11ay, and 5G in the millimeter wave band. Thus, different metrics can be used to assess RF exposure for different wireless communication technologies.

[0047]

[0066] A wireless device (e.g., UE 120) may simultaneously transmit signals using multiple wireless communication technologies. For example, the wireless 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 24-60 GHz band). In some embodiments, the wireless device may simultaneously transmit signals using a first wireless communication technology in which RF exposure is measured in SAR units (e.g., 3G, 4G, 5G in the sub-6 GHz band, IEEE 802.11ac, etc.) and a second wireless communication technology in which RF exposure is measured in PD units (e.g., 5G in the 24-60 GHz band, IEEE 802.11ad, 802.11ay, etc.). As used herein, the sub-6 GHz band may, in some examples, include frequency bands between 300 MHz and 6000 MHz, and in some examples, may include bands in the range of 6000 MHz and / or 7000 MHz.

[0048]

[0067] To assess RF exposure from transmissions using a first technology (e.g., 3G, 4G, 5G in the sub-6 GHz band, IEEE 802.11ac, NTN, etc.), the wireless communication device may include multiple SAR values ​​and / or SAR distributions for the first technology stored in memory (e.g., memory 282 of FIG. 2 or memory 338 of FIG. 3). The SAR values ​​and / or SAR distributions may each correspond to a respective one 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-252r of FIG. 2 or antenna 306 of FIG. 3), frequency bands, channels, and / or body positions, as described further below. In some examples, the stored SAR value includes a single value (e.g., a peak value or a sum of peak values ​​determined based on the description below).

[0049]

[0068] SAR values ​​and / or SAR distributions (also referred to as SAR maps) for each transmit scenario may be generated based on measurements (e.g., E-field measurements) performed in a test laboratory using a human body model. After the SAR values ​​and / or SAR distributions are generated, they may be stored in a memory to enable a processor (e.g., processor 280 of FIG. 2 and / or controller 336 of FIG. 3) to assess RF exposure in real time, as described further below. Each SAR distribution may include a set of SAR values, each of which may correspond to a different location (e.g., on the human body model). Each SAR value may include a SAR value averaged over a 1 g or 10 g mass at the respective location.

[0050]

[0069] 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 SAR scales with transmit power level, the processor may scale the SAR values ​​or SAR distribution for any transmit power level by multiplying each SAR value (e.g., in the SAR distribution) by a transmit power scaler:

[0051]

number

[0052] In the formula, 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 (e.g., the transmit power level at which the SAR value was measured in a test laboratory).

[0053]

[0070] 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 the following: antenna parameters indicating one or more antennas used for transmission (i.e., active antennas); frequency band parameters indicating one or more frequency bands used for transmission (i.e., active frequency bands); channel parameters indicating one or more channels used for transmission (i.e., active channels); body position parameters (e.g., device state index (DSI)) indicating the location of the wireless communication device relative to a user's body location (head, trunk, away from the body, etc.); exposure category; 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 setup (e.g., a test laboratory) can be very time-consuming and expensive. To reduce testing time, measurements may be performed for a subset of the transmission scenarios to generate SAR values ​​and / or SAR distributions for the subset of transmission scenarios. In this example, the SAR values ​​and / or SAR distributions for each of the remaining transmission scenarios may be generated by combining two or more of the SAR values ​​and / or SAR distributions for the subset of transmission scenarios, as described further below.

[0054]

[0071] For example, SAR measurements may be performed for each of the antennas to generate a SAR value or distribution for each of the antennas. In this example, a SAR value or distribution for a transmission scenario in which two or more of the antennas are active may be generated by combining the SAR values ​​or distributions for the two or more active antennas.

[0055]

[0072] In another example, SAR measurements may be performed for each of a plurality of frequency bands to generate a SAR value or distribution for each of the plurality of frequency bands. In this example, a SAR value or distribution for a transmission scenario in which two or more frequency bands are active may be generated by combining the SAR values ​​or distributions for the two or more active frequency bands.

[0056]

[0073] In some embodiments, the SAR distribution may be normalized to a SAR limit by dividing each SAR value in the SAR distribution by the SAR limit. In this case, a 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 embodiments, each SAR distribution stored in memory may be normalized to a SAR limit. Similarly, single or individual SAR values ​​may be normalized to a SAR limit. In some cases, the SAR limit may correspond to a regulatory or standardized limit, or may correspond to a level lower than a regulatory or standardized limit to provide sufficient exposure margin to account for device uncertainties and / or other margins (e.g., for other radios).

[0057]

[0074] In some embodiments, a normalized SAR value or normalized SAR distribution for a transmission scenario may be generated by combining two or more normalized SAR values ​​or normalized SAR distributions. For example, a normalized SAR value or normalized SAR distribution for a transmission scenario in which two or more antennas are active may be generated by combining the normalized SAR values ​​or normalized SAR distributions for two or more active antennas. If different transmit power levels are used for the active antennas, the normalized SAR value or normalized SAR distribution for each active antenna may be scaled by the respective transmit power level before combining the normalized SAR values ​​or normalized SAR distributions for the active antennas. A normalized SAR value or normalized SAR distribution for simultaneous transmission from multiple active antennas may be given by the following equation:

[0058]

number

[0059] In the formula, SAR lim is the SAR limit, and SAR norm_combined is the combined normalized SAR value or 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 value or 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.

[0060]

[0075] Equation (2) can be rewritten as follows:

[0061]

number

[0062] In the formula, SARnorm_i is the normalized SAR value or normalized SAR distribution for the i-th active antenna. In the case of simultaneous transmission at the same transmission frequency using multiple active antennas (e.g., multiple-input multiple-output (MIMO)), the combined normalized SAR value or combined normalized SAR distribution may be obtained by adding the square roots of the individual normalized SAR values ​​or normalized SAR distributions and calculating the square of the sum, as given by the following equation:

[0063]

number

[0064]

[0076] In another example, normalized SAR values ​​or 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 value or normalized SAR distribution for each of the active frequency bands may be scaled by the respective transmit power levels before combining the normalized SAR values ​​or normalized SAR distributions for the active frequency bands. In this example, the combined SAR value or 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 value or 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 normalized SAR value or transmit power level for the normalized SAR distribution for the i-th active frequency band.

[0065]

[0077] To assess RF exposure from transmissions using a second technology (e.g., 5G in the 24-60 GHz band, IEEE 802.11ad, 802.11ay, etc.), the wireless communication device may include multiple PD values ​​and / or PD distributions for the second technology stored in memory (e.g., memory 282 of FIG. 2 or memory 338 of FIG. 3). The PD values ​​or PD distributions may each correspond to a respective one 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-252r of FIG. 2 or antenna 306 of FIG. 3), frequency bands, channels, and / or body positions, as further described below. In some examples, the stored PD includes a single value (e.g., a peak value or a sum of peak values ​​determined based on the description below).

[0066]

[0078] A PD value and / or a PD distribution (also called a PD map) for each transmit scenario may be generated based on measurements (e.g., E-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 may include a set of PD values, and each PD value may correspond to a different location (e.g., on the human body model).

[0067]

[0079] The PD values ​​in each PD distribution correspond to a particular transmit power level (e.g., the transmit power level at which the PD values ​​were measured in a test laboratory). Because PD scales with transmit power level, the processor may scale the PD values ​​or PD distributions for any transmit power level by multiplying each PD value (e.g., in the PD distribution) by a transmit power scaler as follows:

[0068]

number

[0069] In the formula, Tx c is the current transmit power level for each transmission scenario, and Tx PD is the transmit power level corresponding to the PD value (eg, the transmit power level at which the PD value was measured in a test laboratory).

[0070]

[0080] 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 the following: antenna parameters indicating one or more antennas used for transmission (i.e., active antennas); frequency band parameters indicating one or more frequency bands used for transmission (i.e., active frequency bands); channel parameters indicating one or more channels used for transmission (i.e., active channels); body position parameters (e.g., DSI) indicating the location of the wireless communication device relative to a user's body location (head, trunk, away from the body, etc.); exposure category; 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 setup (e.g., a test lab) can be very time-consuming and expensive. To reduce test time, measurements may be performed for a subset of the transmission scenarios to generate PD values ​​and / or PD distributions for the subset of transmission scenarios. In this example, PD values ​​and / or PD distributions for each of the remaining transmission scenarios may be generated by combining two or more of the PD values ​​and / or PD distributions for the subset of transmission scenarios, as described further below. In some cases, the subset of PD distributions generated via measurements may be used to validate a PD distribution obtained from an electromagnetic simulation of a wireless communication device, whereby a PD distribution may be obtained from a simulation for all transmission scenarios supported by the wireless communication device.

[0071]

[0081] For example, PD measurements may be performed for each of the antennas to generate a PD value or PD distribution for each of the antennas. In this example, a PD value or PD distribution for a transmission scenario in which two or more of the antennas are active may be generated by combining the PD values ​​or PD distributions for the two or more active antennas.

[0072]

[0082] In another example, PD measurements may be performed for each of multiple frequency bands to generate a PD value or PD distribution for each of the multiple frequency bands. In this example, a PD value or PD distribution for a transmission scenario in which two or more frequency bands are active may be generated by combining the PD values ​​or PD distributions for the two or more active frequency bands.

[0073]

[0083] In some embodiments, a PD distribution may be normalized to a PD limit by dividing each PD value in the PD distribution by the PD limit, where a 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 PD distribution stored in memory may be normalized to a PD limit. Similarly, single or individual PD values ​​may be normalized to a PD limit.

[0074]

[0084] In some embodiments, a normalized PD value or normalized PD distribution for a transmission scenario may be generated by combining two or more normalized PD values ​​or normalized PD distributions. For example, a normalized PD value or normalized PD distribution for a transmission scenario in which two or more antennas are active may be generated by combining the normalized PD values ​​or normalized PD distributions for two or more active antennas. If different transmit power levels are used for the active antennas, the normalized PD value or normalized PD distribution for each active antenna may be scaled by the respective transmit power level before combining the normalized PD values ​​or normalized PD distributions for the active antennas. A normalized PD value or normalized PD distribution for simultaneous transmission from multiple active antennas may be given by the following equation:

[0075]

number

[0076] During the ceremony, P.D. lim is the PD limit, and PD norm_combined is the combined normalized PD value or combined normalized PD distribution for simultaneous transmissions from the active antennas, i is the index for the active antenna, and PD i is the PD value or PD distribution for the i-th active antenna, and Tx i 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.

[0077]

[0085] Equation (5) can be rewritten as follows:

[0078]

number

[0079] During the ceremony, P.D. norm_iis the normalized PD value or 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 value or combined normalized PD distribution may be obtained by adding the square roots of the individual normalized PD values ​​or individual normalized PD distributions and calculating the square of the sum, as given by the following equation:

[0080]

number

[0081] In some embodiments, a composite normalized PD distribution in a given transmission band may be obtained by taking the maximum value at a given location (x, y, z) from all normalized PD distributions for all antenna configurations of the mmWave module. The composite normalized PD distribution may be used to represent the PD distributions for all antenna configurations of the mmWave antenna module.

[0082]

number

[0083] This PD norm_composite is the PD in Eq. (6a) norm_i where a represents all N beams (or antenna configurations) supported by the i-th mmWave module for a given frequency band. In such a case, Equation (6a) represents combining PD distributions when multiple frequency bands or mmWave antenna modules are active.

[0084]

[0086] In another example, normalized PD values ​​or normalized PD distributions for different frequency bands may be stored in memory. In this example, a normalized PD value or 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 the two or more active frequency bands. If the transmit power levels for the active frequency bands are different, the normalized PD value or normalized PD distribution for each of the active frequency bands may be scaled by the respective transmit power levels before combining the normalized PD values ​​or normalized PD distributions for the active frequency bands. In this example, the combined PD value or 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 value or normalized PD 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 PDi is the normalized PD value or transmit power level for the normalized PD distribution for the i-th active frequency band.

[0085]

[0087] In some cases, compliance with RF exposure limits may be performed as a time-averaged RF exposure assessment within a specified time window (T) associated with the RF exposure limit (e.g., 2 seconds for the 60 GHz band, 100 seconds or 360 seconds for bands ≦6 GHz, etc.).

[0086]

[0088] 4A is a graph 400A of transmit power (P(t)) over time (T) that varies over a time window (T) associated with an RF exposure limit, in accordance with certain aspects of the present disclosure. As an example, the instantaneous transmit power may be a maximum time-averaged transmit power level P(t) at any one transmission occasion within the time window (T). limit That is, the transmit power may exceed a maximum time-averaged transmit power level P limit In some cases, the UE may be configured to transmit at a power of P maxIn some cases, the UE may transmit at a maximum time-averaged transmit power level P limit The maximum time-averaged transmit power level P limit represents the time-averaged threshold for the transmitted power of the RF exposure limit over a time window (T), and in some cases, P limit may be referred to as a maximum time-averaged power level or limit, or in terms of exposure, a maximum time-averaged RF exposure level or limit. Graph 400A also illustrates gaps between transmission bursts, which represent periods of time during which no transmissions were output from the device.

[0087]

[0089] In some cases, the transmit power may be set to a maximum time-averaged transmit power level (e.g., P ) allowed for RF exposure compliance that allows for continuous transmission during the time window. limit ) For example, FIG. 4B illustrates a case where the transmit power is P limit 4B is a graph 400B of transmit power over time (P(t)) illustrating an example where the UE is limited to P(t) to comply with RF exposure limits. limit It can be transmitted continuously.

[0088]

[0090] 4C is a graph 400C of transmit power (P(t)) over time illustrating a time-averaged mode that provides reserve power to allow for continuous transmission within a time window (T) in accordance with certain aspects of the present disclosure. As shown, the transmit power is calculated based on the maximum instantaneous power (P max ) to reserve power (P reserve ), so that the UE can maintain continuous transmission (e.g., maintain a radio connection with the receiving entity) during the time window. reserve ) can continue to transmit. In Figure 4C, max P for the duration of max and P reserve The area between P and T is limit and P reserve , so that the area of ​​the transmit power (P(t)) in FIG. 4C is equal to the area between P(t) and P(t) in the time window T.limit Such an area may be considered to be using 100% of the energy (transmit power or exposure) to remain compliant with the time-averaged RF exposure limits. reserve In the absence of P, the transmitter must use P for a portion of the time window to ensure compliance with the time-averaged RF exposure limits. max In some aspects, P reserve is set to a fixed power used to serve a purpose (e.g., to reserve power for some communications). max The duration of transmission at P is sometimes called the burst transmission time (or high power duration). When more margin becomes available in the future (T seconds later), the transmitter can transmit again at a higher power (e.g., P max It may be possible to transmit (in short bursts at 10 MHz).

[0089]

[0091] In some aspects, the UE may operate at a higher than average power level in the time-averaged mode illustrated in FIG. max Although a single transmission burst is illustrated in FIG. 4C, the UE may instead utilize multiple transmission bursts within a time window (T), e.g., as described herein with respect to FIG. 4A, where the transmission bursts have a transmit power of P reserve It will be appreciated that the transmit power of each transmission burst may be separated by a period maintained at: Further, the transmit power of each transmission burst may vary (within the burst and / or relative to other bursts), with at least a portion of the burst being at a maximum average power level (e.g., P limit ) can be transmitted at a power greater than 100 .mu.m.

[0090]

[0092] 4A-4C illustrate continuous transmission over a window, occasion, burst, etc., it will be understood that a duty cycle for transmission may be implemented. In such implementations, the transmit power may be zero periodically and maintained at a higher level (e.g., the level illustrated in FIGS. 4A-4C) during other portions of the duty cycle. As used herein, a duty cycle of transmission may refer to a portion (e.g., 5 ms) of a particular period (e.g., 500 ms) during which one or more signals are transmitted. In some cases, the duty cycle may be standardized (e.g., predetermined) with a particular RAT and / or may vary over time due to, for example, changes in radio conditions, mobility, and / or user behavior.

[0091] Exemplary RF Exposure Measurements

[0093] In some cases, the RF exposure of a wireless device may be certified by a regulatory agency (e.g., the Federal Communications Commission (FCC)). Spatial measurements may be performed on a model (phantom) representing a human body, and the model may be filled with a fluid simulating human tissue. As described above, the 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 for the first and second technologies using various metrics (e.g., SAR for the first technology and PD for the second technology). 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 (simulated and / or measured) may then be generated for each transmit antenna / configuration (beam) (as described above) over all evaluation surfaces / positions at all locations.

[0092]

[0094] 5 illustrates an example system 500 for measuring RF exposure values ​​or distributions in accordance with certain aspects of the present disclosure. As shown, RF exposure measurement system 500 includes a processing system 502, a robotic RF probe 504, and a human body model 506. RF exposure measurement system 500 may perform RF measurements in various transmission and / or exposure scenarios associated with UE 120. In some examples, these measurements may be used to generate an RF exposure map and assess suitable back-off factors for the transmit power of antenna 252 that comply with one or more RF exposure limits, as described further herein. UE 120 may emit electromagnetic radiation via antenna 252 at various transmit powers, and RF exposure measurement system 500 may perform RF measurements via robotic RF probe 504 (e.g., to determine an RF exposure map and / or back-off factors for antenna 252).

[0093]

[0095] 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 include 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 communicate with the robotic RF probe 504 via an interface 514 (such as a computer bus interface) so that the processor 508 can, for example, obtain RF measurements taken by the robotic RF probe 504 and control the position of the robotic RF probe 504 relative to the human body model 506.

[0094]

[0096] The memory 510 may be configured to store instructions (e.g., computer-executable code) that, when executed by the processor 508, cause the processor 508 to perform various operations. For example, the memory 510 may store instructions for obtaining RF exposure distributions associated with various RF exposure / transmission scenarios and / or for adjusting the position of the robotic RF probe 504.

[0095]

[0097] The robotic RF probe 504 may include an RF probe 516 coupled to a robotic arm 518. In some aspects, 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 millimeter wave 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.

[0096]

[0098] The human body model 506 may be a custom-made anthropomorphic mannequin with simulated human tissue. For example, the human body model 506 may include one or more fluids that simulate 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 that complies with various RF exposure limits.

[0097]

[0099] In some embodiments, the RF exposure values ​​or distributions associated with the UE 120 may be measured without the use of the human body model 506. For example, the RF probe 516 may be an electric or magnetic field probe capable of estimating the SAR and / or PD in free space surrounding the UE 120.

[0098]

[0100] Although the example depicted in FIG. 5 is described herein with respect to obtaining RF exposure values ​​or distributions 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 a human body model 506 or in free space.

[0099] Exemplary Compressed Radio Frequency Exposure Map

[0101] A multi-mode / multi-band UE has multiple transmit antennas that can simultaneously transmit in sub-6 GHz bands and bands above 6 GHz, such as millimeter wave bands. As described herein, RF exposure in sub-6 GHz bands may be evaluated in SAR units, and RF exposure in above 6 GHz bands may be evaluated in PD units. Due to regulations on simultaneous exposure, wireless devices may limit their maximum transmit power for both sub-6 GHz bands and above 6 GHz bands.

[0100]

[0102] In some cases, the complete SAR and PD distributions may be used to determine the maximum allowable transmit power for a future time interval in accordance with the time-averaged RF exposure limits, as described herein. Assuming n sub-6 GHz antennas for SAR exposure and n mmWave antennas for mmWave exposure, with the sub-6 GHz radios averaged over a T time window and the mmWave radios averaged over a T time window, these time windows may be divided into p and q "Δt" time intervals, respectively (e.g., p = T / Δt, q = T / Δt), and the total RF exposure may be determined according to the following equation:

[0101]

number

[0102] During the ceremony,

[0103]

number

[0104]

[0103] In the jth Δt time interval, the SAR and PD exposures are limit The SAR and PD exposure maps may be calculated by summing the transmit powers of each radio normalized to √{square root over (x,y,z)} and scaling the sum of the transmit powers by the normalized exposure map (e.g., norm.SAR.exp.map(x,y,z) and norm.PD.exp.map(x,y,z)). Note that the pth and qth time intervals represent future transmissions. The wireless device calculates the allocated margin for all sub-6 GHz radios in the pth time interval and for all mmWave radios in the qth time interval. Such a process ensures compliance with the time-averaged RF exposure limits. If the entire SAR and PD exposure map were used for all or any of the six surfaces of the wireless device, the calculations to predict future transmit powers for RF exposure compliance may be computationally intensive and impractical for some wireless devices, such as portable wireless devices.

[0105] Aspects of the present disclosure provide apparatus and methods for generating and / or using a compressed RF exposure map, where the RF exposure map may represent the maximum RF exposure indicated for certain individual radios and / or combinations of radios in a particular region associated with a wireless device. The RF exposure map is reduced to the maximum RF exposure in a region, whereby the wireless device may assess RF exposure compliance over the region identified for the RF exposure map. In some aspects, the RF exposure map may represent RF exposure in terms of SAR and / or PD.

[0106] It should be noted that, as used herein, a region of an RF exposure map may or may not represent an actual point or area of ​​a wireless device. In some cases, for example, a region of an RF exposure map may represent one or more points on a wireless device. For example, a region may represent a single point on a wireless device or a set of points on a wireless device. When a region represents a set of points on a wireless device, the set of points may be a set of contiguous points or a set of non-contiguous points (or scattered points). In some cases, a region of an RF exposure map may represent a collection of sets of points on a wireless device, where each respective set of points corresponds to a different area (within the region) of the wireless device. Each respective set of points in the collection may include contiguous points or non-contiguous points. In some cases, a region of an RF exposure map may include one or more contribution values. A contribution value may not represent an actual point on a wireless device or an RF exposure map. For example, the contribution values ​​may be based on the overlap of exposure distributions between different technologies / antennas of interest (e.g., radios, antennas (or antenna modules), beams, bands, or combinations thereof). In some cases, the contribution values ​​may be determined from simulations of various exposure / transmission scenarios. For example, assuming a user, manufacturer, and / or service provider decides to reduce the map of multiple antennas, the interactions between the antennas may be evaluated during simulation to determine a contribution matrix having contribution values ​​that ensure RF exposure compliance.

[0107] The apparatus and methods for generating and using RF exposure maps described herein may facilitate improved wireless communication performance (e.g., improved signal quality at the receiver, lower latency, higher throughput, etc.). The apparatus and methods for generating and using RF exposure maps described herein may also enable improved processing performance, for example, by reducing the memory size used by the RF exposure map and / or reducing the number of calculations used to perform RF exposure assessments to meet time-averaged RF exposure compliance during simultaneous transmission scenarios.

[0108]

[0107] Exposure maps associated with a wireless device may be generated for various combinations of transmission and / or exposure scenarios, such as an exposure map for each antenna (and / or antenna module) of the wireless device. Assuming there are m regions identified for the RF exposure map, instead of performing calculations for the complete exposure distribution for all of the exposure maps associated with the antennas, m regions may be considered for each exposure distribution, for example, according to the following equation:

[0109]

number

[0110] In the above equations, the initial SAR / PD matrix size is significantly reduced through the process described herein (e.g., in most cases, a reduction of less than about 0.5 decibels (dB) compared to using the full exposure distribution approach) with minimal sacrifice in achievable transmit power levels. For example, a full exposure distribution associated with a device measuring 21 centimeters by 16 centimeters with eight antennas and 1 mm resolution may have over 200,000 points to perform the calculation on a single surface. In some cases, the compressed RF exposure map described herein may have fewer than 100 regions (e.g., ≦88) to achieve results similar to the full exposure distribution approach, with a small sacrifice in transmit power (e.g., about 0.5 dB).

[0111] 6 is a flow diagram illustrating example operations 600 for generating a compressed RF exposure map. Operation 600 may be performed using a processing system (e.g., processing system 502) or another computing device. As described herein with respect to operation 600, FIG. 7 is a diagram illustrating the progression of generating a compressed RF exposure map from one or more RF distributions.

[0112] The operations 600 may optionally begin at block 602, where a processing system may obtain an exposure map (e.g., total normalized exposure map 702) covering exposure exhibited by all (or at least some) of the radios, antennas (or antenna modules), beams, and / or bands supported by the wireless device, for example. The processing system may obtain multiple composite normalized exposure maps associated with the multiple exposure maps, for example, by adding the individual normalized maps. The obtained exposure map may be a total exposure map derived from a set of normalized composite exposure maps (e.g., normalized RF exposure distributions). The composite exposure maps may be normalized with respect to respective RF exposure limits (e.g., SAR limits and / or PD limits). In some cases, the processing system may obtain the RF exposure distribution using, for example, the 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 device. The set of normalized exposure maps may represent, for example, the exposures presented by sub-6 GHz and / or mmWave antennas and supported by the wireless device.

[0113] In block 604, the processing system may divide (e.g., segment) the total exposure map into smaller regions, such as regions 704. For example, the processing system may identify a region for each of the largest contributions of each radio, antenna (or antenna module), beam, and / or band in the region, allowing the RF distribution to be reduced to a region that sums the number of largest contributions of each radio, antenna (or antenna module), beam, and / or band in the region.

[0114] At block 606, the processing system may select a subset of regions (e.g., a subset of regions 706). The processing system may perform an iterative process to determine whether a maximum RF exposure associated with the subset of regions provides RF exposure compliance. If RF exposure compliance is not met for the selected subset of regions, the processing system may reselect the regions to be included in the subset, for example, by adding one or more regions to the subset. The regions selected for the subset may be based on certain constraints, such as wireless performance constraints (e.g., tolerances) and / or memory constraints (e.g., size of an RF exposure map).

[0115] In block 608, the processing system may identify the maximum RF exposure in each of the regions in the subset. In some cases, the processing system may store the maximum RF exposure associated with the subset of regions as a table (e.g., table 708). After identifying the subset of regions (e.g., m regions), the processing system may obtain reduced normalized exposure maps within the selected subset of regions (m regions) for the composite map (e.g., n normalized exposure maps obtained in block 602) used to create the total exposure map. For example, the maximum RF exposure (e.g., m×n value) in each subset of regions of the composite map may be determined according to the following formula: normalized exposure map(exposure map i,region j)= max(exposure_mapi (x,y,z),(x,y,z)∈region j) (8) where i is a sequence from 1 to n and j is a sequence from 1 to m.

[0116] In some embodiments, the exposure distribution obtained in block 602 may be determined (e.g., measured or simulated) for all antennas in the low, medium, and high channels for all supported bands. As described above, the RF exposure distribution may include RF exposure associated with various transmit scenarios corresponding to a particular frequency band and / or human body position relative to the antenna or antenna module. For example, the RF exposure distribution may be expressed 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 / medium / 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 at each location / exposure surface from all technologies / bands / channels supported by the transmit antenna. In some cases, a transmit antenna module may support multiple antenna configurations (or beams), and therefore the RF exposure distribution for a particular transmit antenna module may represent the maximum exposure at each location / exposure surface among all beams supported by the transmit antenna module.

[0117]

[0115] A composite map may be determined for each antenna per band (e.g., maximum exposure of low, medium, and high channels at each location (x, y, z) across the surface). A composite map may be determined for each antenna (e.g., maximum exposure of all bands for a given antenna). Assuming a given antenna can support 40 bands, those bands may be divided into subsets of bands. For example, a first band b1 may include bands 1, 5, and 8 (e.g., b1 = {band 1, band 5, and band 8}), a second band b2 may include bands 3 and 9 (e.g., b2 = {band 3, band 9}), a third band b3 may include bands 2 and 32 (b3 = {band 2, band 32}), and so on, with the superset being b1 + b2 + b3 + ... = 40 bands. A composite map may be determined for each antenna per subset of bands. The set of composite maps covering all (or at least some) antennas and all (or at least some) bands may include (1) a composite map per antenna (or antenna module), (2) a composite map per antenna per band, or (3) a composite map per antenna per subset of bands, or a combination thereof.

[0118] 8 is a diagram illustrating eight normalized composite maps 802 per antenna being added together to obtain a total exposure map 804. In this example, each of the composite maps 802 may be normalized to 1.0 using a respective RF exposure limit (e.g., a SAR limit or a PD limit), and the total exposure map 804 may have points greater than 1.0 due to finite overlap between the distributions of the composite maps.

[0119]

[0117] At block 604, the processing system may perform various activities to divide (e.g., segment) the total exposure map into regions. The processing system may remove compliant locations from the total exposure map. For example, to remove compliant locations, the processing system may set values ​​associated with locations having normalized values ​​less than or equal to a threshold value (e.g., 1.0) to a default value, such as zero. FIG. 9 illustrates an example total exposure map 902 and an updated version of the total exposure map 904 with compliant locations set to a particular value (e.g., zero). Note that in other aspects, instead of dividing the total exposure map into regions at block 604, the processing system may consider certain regions of individual exposure maps (e.g., composite map 802) as regions, such as region 704. Additionally, the processing system may evaluate contributions from different technologies / antennas of interest when determining regions, such as region 704.

[0120] The processing system may identify one or more non-compliant regions in the updated total exposure map (e.g., regions having an exposure value of 1.0 or greater). FIG. 10 illustrates an example of identifying non-compliant regions until all of the non-compliant areas are covered by identified regions 1010. For example, the processing system may identify a non-compliant region (e.g., non-compliant region 1002) as a region having a peak exposure value among the exposure values ​​in the updated total exposure map. The processing system may temporarily remove the identified region from the total exposure map for subsequent division of the total exposure map. The processing system may iteratively identify the next non-compliant region having a peak exposure value (e.g., non-compliant regions 1006, 1008) until all of the non-compliant regions are covered by at least one region. For example, the processing system may remove the region selected in the previous iteration (e.g., boundary 1004 of region 1002) from the non-compliant map. The processing system may repeat identifying and removing non-compliant regions until all non-compliant regions (e.g., non-compliant region 1010) are identified. Once all non-compliant regions are covered, the processing system may save the identified regions. The processing system may obtain the maximum contribution of the exposure map in each of the regions and save the corresponding contribution.

[0121] In some embodiments, the processing system may apply a threshold contour, such as a 95% contour, to identify non-compliant regions (e.g., non-compliant region 1002). The contour level may be any non-zero value less than 100%. The 95% contour may provide efficient processing time for executing the algorithm. The contour represents a boundary within which all points have a value higher (greater) than the contour threshold (e.g., the product of the contour and the maximum value of the total exposure map).

[0122] The processing system may approximate the contour boundary as a rectangle or any other suitable polygon. For example, the processing system may determine a rectangular boundary (e.g., boundary 1004) that encompasses the contour boundary of the non-compliant region. Any polygonal shape or the contour shape itself may be used for the boundary of the non-compliant region. A rectangular boundary may use two starting coordinates, a length, and a width value, while other shapes may use more memory to store the region boundary. Strategically selecting or fine-tuning the region (e.g., the size and shape of the exposure contour) may provide improved performance with respect to back-off factors, as further described herein.

[0123] The processing system may identify the maximum contribution of each antenna in the non-compliant region, the worst interaction between antennas in the non-compliant region (e.g., the maximum contribution between a set of antennas), or a combination thereof. The processing may determine whether the sum of the maximum contributions from all antennas is less than or equal to the maximum value of the total exposure map plus a tolerance value, where the tolerance value may vary based on a criterion for the number of reduced regions. The tolerance value may be used to adjust the amount of power reduction obtained using the compressed RF exposure map. A higher tolerance value used to generate the compressed RF exposure map results in fewer regions being identified in the subset, as described further herein, which uses fewer processing resources (e.g., instructions per second and / or memory) and provides a higher backoff. A lower tolerance value used to generate the compressed RF exposure map results in more regions being identified in the subset, which uses more processing resources and provides a lower backoff. The number of regions in the subset may be controlled by specifying an acceptable tolerance value, which may correspond to expected performance compared to the full resolution map.

[0124] If the condition is not met (e.g., maximum contribution > maximum + tolerance), the contour level is increased to a value greater than the starting contour (e.g., 96%), and the boundary of the non-compliant region is re-determined using the updated contour level. Note that while embodiments herein describe increasing the contour level, in general, embodiments may vary the size of the area of ​​the target exposure map until the condition is met. If the condition is met (e.g., maximum contribution < maximum + tolerance), the identified non-compliant region is stored in memory along with the maximum contribution of each exposure map within the region, and this identified region is removed for subsequent division of the total exposure map. If two or more non-compliant regions are iteratively identified, it may be verified that all of the non-compliant regions meet the condition. In some cases, non-compliant regions that meet the condition may be considered valid and removed without discarding all identified rectangles.

[0125] To determine the subset of non-compliant regions in block 606, the processing system may perform an iterative process to select a subset of non-compliant regions sufficient to demonstrate RF exposure compliance for the full resolution map. Multiple points in each normalized map are represented by points in the subset of regions. The number of subset regions selected may vary based on various criteria, such as constraints imposed on device performance (e.g., tolerances in algorithms) and memory usage. This selection may be performed during a calibration process, for example, at a factory or manufacturing facility, or during a testing or compliance process. The selection may alternatively be performed on the wireless device, for example, due to configuration input by a manufacturer or software developer, or based on user input. During the iterative process, back-off information (e.g., a back-off factor) may be calculated using m1 points of the i exposure maps for all p ON / OFF scenarios associated with the antenna, where p is 2 i-1 For a given qth ON / OFF scenario, if the map is either ON=1 or OFF=0, denoted by on_off(q), the compressed total normalized exposure can be verified as follows:

[0126]

number

[0127] where bf(q,k) is a back-off factor associated with an antenna, antenna module, or antenna group, j is a sequence from 1 to m1, and norm.reduced.map(k,j) is the exposure map reduced to a subset of regions. The back-off factor can be adjusted until the total normalized exposure meets a threshold (e.g., ≦1).

[0128] As used herein, a back-off factor may be a specific 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 a normalized distribution of the RF exposure distribution, generate a normalized composite map of the normalized distribution for each of the antennas (or antenna modules or antenna groups), and generate a sum of the normalized composite maps for all of the antennas based on the back-off factor associated with each of the antennas (or antenna modules or antenna groups). As an example, the back-off factor bf may be between [0, 1] for each antenna group, such that the maximum allowed transmit power for each antenna is the respective back-off factor multiplied by the transmit power limit for the antenna (e.g., bf * Tx_power_limit), where bf=1 represents no backoff and bf=0.3 means operating the antenna group at 30% of the transmit power limit, which may be the maximum transmit power supported by that particular antenna and / or antenna group.

[0129]

[0125] For each ON scenario (eg, q=1) among the p ON / OFF scenarios, the back-off factor bf(q,k) can be verified to be valid for the full resolution map using the following equation:

[0130]

number

[0131] To confirm that the selected regions represent the full resolution map, the processing system may determine that m points of the selected subset of regions meet the above criteria for all p ON / OFF combinations. The subset of regions may be selected such that a back-off determined using the subset of regions provides RF exposure compliance for the full resolution map. The number of regions in the subset may be determined by performance limitations such as processing power. Various approaches may be used to reduce the full resolution map to a subset of regions, such that a back-off obtained using the subset demonstrates RF exposure compliance when applied to the full resolution map.

[0132] In some embodiments, the subset of non-compliant regions may be adjusted based on the back-off information. For example, the processing system may start with an initial non-compliant region (e.g., the rectangle determined in block 604) and check whether the back-off value obtained for the region is sufficient to handle all (or at least some) of the antenna ON / OFF situations when back-off is applied to the full resolution map. If the back-off value fails for a particular test case, the processing system may adjust the region to include the maximum exposure point for the test case. For example, the processing system may find the region to which the maximum exposure point belongs and include that region in the back-off calculation. The processing system may repeat such adjustments until the calculated back-off values ​​are valid for all (or at least some) of the antenna ON / OFF situations. Following this adjustment, all of the regions in the subset may meet RF exposure compliance. The processing system may store the maximum contribution from each antenna in the identified region in a matrix (or table) format.

[0133] 11 illustrates an example of a subset of non-compliant regions 1102 selected for a compressed RF exposure map, such as selected in block 606. For example, the subset of non-compliant regions 1102 may be determined using back-off verification as described herein.

[0134] 12 illustrates an example of a subset of composite maps 1202a-h and non-compliant regions, where each of the composite maps 1202a-h is associated with a contribution from a different antenna (or antenna module). As described herein, the maximum value within the identified region 1102 may be stored for each of the different composite maps 1202a-h to perform time-averaged RF exposure compliance, for example, as described herein with respect to FIGS.

[0135] 13 illustrates an example table 1300 of maximum RF exposure values ​​per region (e.g., a subset of regions) associated with a particular map. In this example, the table may have a size of M×N, where the maximum contribution within each identified region from the N composite maps is stored for the M identified regions.

[0136] 14 is a flow diagram illustrating example operations 1400 for generating an RF exposure map. The operations 1400 may be performed using a processing system (e.g., processing system 502) or any other computing device. The operations 1400 may optionally begin at block 1402, where the processing system may obtain a normalized composite exposure (e.g., SAR and / or PD) map for each radio, antenna (or antenna module), beam, and / or band supported by the wireless device.

[0137] At block 1404, the processing system may combine the composite exposure maps to generate a total exposure map (e.g., total exposure map 804). To combine the composite exposure maps, the processing system may add the composite exposure maps together to form a total exposure map (e.g., a sum of the composite exposure maps).

[0138]

[0133] At block 1406, the processing system may divide the total exposure map into smaller regions. For example, the processing system may use the contour and removal approach described herein with respect to Figures 9 and 10 to identify non-compliant regions in the total exposure map.

[0139]

[0134] In block 1408, the processing system may add the regions containing the highest exposure values ​​for each of the composite exposure maps to a reduction matrix (e.g., a compressed RF exposure map represented as a table or matrix), for example, as described herein with respect to Figures 12 and 13.

[0140] At block 1410, the processing system may perform a power back-off calculation for an ON / OFF status associated with the antenna using the reduction matrix. The processing system may use the reduction matrix to determine back-off information (e.g., back-off coefficient values) associated with the antenna.

[0141]

[0136] In block 1412, the processing system may apply the power back-off value to the full resolution exposure map (eg, total exposure map 902).

[0142]

[0137] In block 1414, the processing system may determine whether there are any non-compliant regions in the full resolution exposure map with the back-off value applied.

[0143] At block 1416, if a non-compliant region is identified in the full resolution exposure map, the processing system may add the region to the reduction matrix. If no non-compliant region is identified in the full resolution exposure map, the processing system may consider the reduction matrix complete.

[0144] The operations described herein for generating a compressed RF exposure map can be performed for any set of SAR and / or PD distributions. A compressed RF exposure map can be generated for any number of composite maps, distributions of exposure in those composite maps, and overlaps in the distributions. The operations described herein can be used to reduce any combination of normalized SAR or normalized PD maps.

[0145] FIG. 15 is an example plot 1500 illustrating the average back-off difference in decibels for different ON / OFF combinations of antennas across different test cases. The back-off difference is between the back-off calculated using a reduced exposure map (e.g., table 1300 depicted in FIG. 13) and the back-off calculated using the full exposure map. In this example, the back-off is evaluated from a compressed exposure map and a full resolution exposure map derived from a composite exposure map associated with eight antennas, with a total of 255 (e.g., 2 8The backoff is equal to -1), the tolerance is equal to 0.4 (y=0.4), and the contour is equal to 0.95 (x=0.95). The compressed exposure map may have m regions, and in this example, m is equal to 11. The difference between the above two approaches for determining the backoff shows that the compressed RF exposure map incurs minimal performance impact. The performance loss may be inversely proportional to the number of regions m included in the compressed RF exposure map. For example, when m is equal to 1, all distributions are represented by the highest exposure value, which is equivalent to all antennas being co-located. As m approaches the number of points in the full resolution map, the performance loss decreases and processing resources (e.g., number of calculations and / or memory size) increase. As demonstrated in the graph, there is no performance loss for a single transmission scenario (e.g., only one composite map is active) because there is no overlap with other composite maps, and the performance loss is minimal for other transmission scenarios. For simultaneous scenarios with five or fewer antennas active, the average additional backoff is less than 1 dB. A compressed RF exposure map can significantly reduce the number of calculations (eg, by a factor of 3,000).

[0146] In some embodiments, the RF exposure map may be divided into multiple regions, and the RF exposure map may be compressed by obtaining the maximum RF exposure in each of the regions. For example, FIG. 16 is a diagram illustrating an RF exposure map 1602 segmented into multiple regions 1604. In this example, the RF exposure map 1602 may be compressed by identifying the maximum RF exposure value for each of the regions 1604, and the maximum RF exposure value in the region 1604 may represent the compressed RF exposure map. The regions 1604 may be arranged in a grid or matrix (e.g., an M×N grid) across the RF exposure map 1602. In some embodiments, each of the regions 1604 may have the same size or dimensions.

[0147] 17 is a flow diagram illustrating example operations 1700 for generating an RF exposure map. Operations 1700 may be performed using a processing system (e.g., processing system 502) or any other computing device.

[0148] The operations 1700 may optionally begin at block 1702, where a processing system may obtain a first RF exposure map (e.g., total exposure map 804) associated with at least one antenna of a wireless device. In some aspects, the first RF exposure map may be obtained by measuring RF exposure using measurement system 500. In some cases, the first RF exposure map may be simulated using a model of a radiation pattern emitted from the wireless device.

[0149] At block 1704, the processing system may convert the first RF exposure map into a second RF exposure map, where the second RF exposure map is compressed compared to the first RF exposure map. For example, the second RF exposure map may represent maximum normalized exposure levels for a subset of regions in the first RF exposure map. To convert the first RF exposure map into the second RF exposure map, the processing system may use the first RF exposure map to generate a look-up table (e.g., table 1300 depicted in FIG. 13) of exposure contributions across different regions. In some embodiments, the compressed RF exposure map may correspond to maximum RF exposure values ​​associated with different regions, for example, as described herein with respect to FIG. 16.

[0150] In some aspects, the first RF exposure map may be derived from a composite RF exposure map. For example, to obtain the first RF exposure map, the processing system may obtain multiple RF exposure maps (e.g., normalized composite map 802), each representing an RF distribution for a different antenna of the wireless device. The processing system may combine the multiple RF exposure maps to form the first RF exposure map, for example, as described herein with respect to FIG. 8. The first RF exposure map may include normalized RF exposure contributions (e.g., normalized composite map) from multiple antennas of the wireless device. The first RF exposure map shows RF exposure contributions across one or more surfaces of the wireless device (e.g., top, bottom, front, back, left, and / or right surfaces) from the multiple antennas of the wireless device. The first RF exposure map may represent RF exposure contributions across one surface or multiple surfaces of the wireless device, and the distributions for multiple surfaces of the wireless device may be represented in a single RF exposure map. The first RF exposure map may include a representation of RF exposure contributions arranged in at least two dimensions (eg, an x-axis and a y-axis).

[0151] In aspects, the processing system may segment the first RF exposure map into multiple regions (e.g., a subset of the non-compliant region 1102), e.g., as described herein with respect to FIGS. 10 and 11. For each of the regions, the processing system may select a maximum RF exposure value from among multiple values ​​in the respective region. For example, the processing system may select, for each region, a maximum RF exposure value from each of the composite exposure maps associated with the total exposure map. The processing system may generate the second RF exposure map as the selected maximum RF exposure values ​​in the regions, e.g., as described herein with respect to FIGS. 13 and / or 16. In some cases, the compressed RF exposure may be the selected maximum RF exposure value in the region.

[0152] In some aspects, the processing system may perform an iterative process to transform the first RF exposure map, e.g., as described herein with respect to FIGS. 8-14. The processing system may determine a total normalized composite RF exposure map for multiple antennas based on a back-off factor and the first RF exposure map at a reduced resolution (e.g., using a subset of region 1102), e.g., according to Equation (9). For example, the processing system may adjust the back-off factor until the total normalized composite RF exposure meets a threshold (e.g., ≦1). The processing system may re-segment the first RF exposure map into multiple regions, e.g., according to Equation (10), until the back-off factor meets a threshold for calculating a total normalized composite RF exposure map at the full resolution of the first RF exposure map.

[0153] 18 , a wireless device may use the compressed RF exposure map to determine a transmit power that complies with time-averaged RF exposure limits. For example, the wireless device may access a second RF exposure map associated with at least one antenna of the wireless device, the second RF exposure map including a representation of maximum RF exposure for an area. The wireless device may transmit signals from the at least one antenna at a transmit power that complies with RF exposure limits (e.g., time-averaged SAR limits) determined at least in part based on the second RF exposure map.

[0154] FIG. 18 is a flow diagram illustrating example operations 1800 for wireless communication according to certain aspects of the present disclosure. The operations 1800 may be performed, for example, by a wireless device (e.g., UE 120a in wireless communication network 100). The operations 1800 may be implemented as software components executing and running on one or more processors (e.g., controller / processor 280 of FIG. 2). Furthermore, transmission and / or reception of signals by the wireless device in operations 1800 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 wireless device may be implemented via a bus interface of one or more processors (e.g., controller / processor 280) that acquires and / or outputs signals.

[0155] The operations 1800 may optionally begin at block 1802, where a wireless device may access an RF exposure map (e.g., a compressed RF exposure map represented by table 1300 depicted in FIG. 13) associated with at least one antenna of the wireless device (e.g., antenna 252 in FIG. 2), the RF exposure map including a representation of maximum RF exposure for a region of the RF exposure map, such as at least one of regions 1102 in FIG. 11. The wireless device may access the RF exposure map as a table or other data structure via a memory. For example, the RF exposure may be stored in memory (e.g., memory 282 and / or memory 338), and the wireless device may access the memory to obtain the RF exposure map. The antenna may include multiple antenna elements operable in a range of frequency bands (e.g., sub-6 GHz and / or millimeter wave frequency bands).

[0156] At block 1804, the wireless device may transmit a signal from at least one antenna at a transmit power that complies with RF exposure limits, determined at least in part based on the RF exposure map. In some cases, the wireless device may transmit simultaneously via a single antenna or multiple antennas, where simultaneous transmission may include transmission on the same transmission occasion, the same time interval, or the same time window associated with an RF exposure limit. In some cases, the wireless device may transmit simultaneously via a single radio or multiple radios. For example, the wireless device may transmit simultaneously via any combination of an LTE / NR radio, a WiFi radio (e.g., an IEEE 802.11 channel), and / or a Bluetooth radio. In some cases, the wireless device may have transmitted via multiple radios within the same time window defined by a regulatory agency or standard to average RF exposure. For example, a wireless device may transmit over any (2G / 3G / 4G / 5G) wireless wide area network (WWAN) radio in a first time interval and then transmit over a WiFi radio in a second time interval, both time intervals being within a time averaging window specified by a regulatory agency or standard.

[0157] The RF exposure map may represent RF exposure contributions from multiple antennas of a wireless device. For example, the RF exposure map may include maximum RF exposure values ​​associated with multiple composite exposure maps (e.g., composite maps 1202a-h) within a subset of a region (e.g., region 1102). The RF exposure map may represent RF exposure contributions arranged in at least two dimensions (e.g., an x-axis and y-axis coordinate system, or an x-axis, y-axis, and z-axis coordinate system). The RF exposure map may represent RF exposure contributions across one or more surfaces of a wireless device. In some aspects, the RF exposure map may be represented as a look-up table of maximum RF exposures associated with multiple regions, for each antenna among multiple antennas of a wireless device, as depicted in FIG. 13, for example. In some aspects, the RF exposure map may represent RF exposure contributions from at least one antenna of a wireless device to one or more RF exposure scenarios (e.g., head exposure, hand or limb exposure, trunk or torso exposure, and / or hot spot exposure scenario). The representation of the maximum RF exposure for the area may enable determination of the transmit power of at least one antenna to ensure compliance with RF exposure limits.

[0158] In some embodiments, the RF exposure contribution from the antenna spans a range of frequencies. The range of frequencies may include a sub-6 GHz band, a millimeter-wave band, or a combination thereof. The RF exposure contribution may be derived from multiple bands, such as a sub-6 GHz band and a millimeter-wave band. The RF exposure contribution includes a first RF exposure contribution from the sub-6 GHz band and a second RF exposure contribution from the millimeter-wave band.

[0159] The region corresponding to the maximum RF exposure in the RF exposure map may include an area of ​​multiple points in the RF exposure map. The region may be a subregion (or subarea) of a larger exposure region associated with at least one antenna. The region may be a collection of one or more points belonging to the larger exposure region associated with at least one antenna. For example, in some cases, the region may be a single point or a sparse collection of points (which may not include an area or contiguous points). The RF exposure map includes a representation of the maximum RF exposure for each of the multiple regions (e.g., region 1102) that comprise the region.

[0160] In some aspects, a wireless device may use back-off information (e.g., one or more back-off factors) applied to an RF exposure map to determine transmit power. For example, the wireless device may adjust the RF exposure map by the back-off factors to determine RF exposure compliance.

[0161] In some aspects, a wireless device may use multiple RF exposure maps to determine RF exposure compliance, with each RF exposure map associated with a different exposure scenario or transmission scenario for the wireless device. For example, to access an RF exposure map, the wireless device may access an RF exposure map from multiple RF exposure maps, with each RF exposure map representing a different exposure or transmission scenario (e.g., combinations of antennas ON / OFF across the wireless device) or a different set of exposure scenarios for the wireless device. The different exposure or transmission scenarios may include various combinations of active or inactive radios, beams, bands, antennas, and / or antenna groups. For example, each RF exposure map may be associated with a different combination of one or more active antennas among multiple antennas of the wireless device. In some cases, the different exposure or transmission scenarios may correspond to different positions and / or proximity to the human body (e.g., head exposure, hand or limb exposure, torso or torso exposure, and / or hotspot exposure scenario). The set of exposure scenarios may correspond to any combination of head exposure, hand or extremity exposure, trunk or torso exposure, and / or hot spot exposure scenarios.

[0162] In some aspects, a wireless device may determine a transmit power for a future time interval within a time window associated with a time-averaged RF exposure limit. For example, the wireless device may obtain a total transmit power for past time intervals within the time window associated with the RF exposure limit. The wireless device may have transmitted with a different exposure or transmission scenario during any of the past time intervals within the time window associated with the RF exposure limit. The wireless device may determine an interim transmit power for a future time interval within the time window. The wireless device may convert the sum of the interim transmit power and the total transmit power into a time-averaged RF exposure value for the time window based on the RF exposure map. The wireless device may adjust the interim transmit power such that the time-averaged RF exposure value satisfies the RF exposure limit. The wireless device may transmit a signal at a transmit power that is less than or equal to the adjusted interim transmit power that satisfies the RF exposure limit. In some aspects, the RF exposure limit may include a time-averaged SAR limit, a time-averaged PD limit, or any combination thereof.

[0163] 1-18 are described herein with respect to a UE that implements various methods for providing RF exposure compliance for ease of understanding, however, aspects of the present disclosure may also apply to other wireless devices, such as wireless stations, access points, base stations, and / or customer premises equipment (CPE), that implement RF exposure compliance as described herein. Furthermore, while the examples are described with respect to communications between a UE (or other wireless device) and a network entity, the UE or other wireless device may communicate with devices other than a network entity, e.g., another UE, or another device in a user's home that is not a network entity.

[0164] It will be appreciated that the compressed RF exposure maps described herein may enable desirable wireless communication performance, such as reduced latency, increased uplink data rates, and / or uplink connectivity at the edge of a cell. The compressed RF exposure maps described herein may provide efficient RF exposure compliance with region-specific RF exposure values ​​for the RF exposure map.

[0165] Exemplary Communication Devices 19 illustrates a communications device 1900 (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 the operations illustrated in FIG. 17, the operations illustrated in FIG. 18, or other operations described herein for providing RF exposure compliance. The communications device 1900 includes a processing system 1902 that may be coupled to a transceiver 1908 (e.g., a transmitter and / or a receiver). The transceiver 1908 is configured to transmit and receive signals for the communications device 1900 via an antenna 1910, such as various signals as described herein. The processing system 1902 may be configured to perform processing functions for the communications device 1900, including processing signals received by the communications device 1900 and / or to be transmitted.

[0166] The processing system 1902 includes a processor 1904 coupled to a computer-readable medium / memory 1912 via a bus 1906. In some aspects, the computer-readable medium / memory 1912 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1904, cause the communications device 1900 to perform operations 1700 illustrated in FIG. 17 , operations 1800 illustrated in FIG. 18 , or other operations for implementing various techniques described herein for providing RF exposure compliance. In some aspects, the computer-readable medium / memory 1912 stores code 1914 for accessing (or obtaining), code 1916 for transmitting (or outputting), code 1918 for converting, or any combination thereof.

[0167] In some aspects, the processing system 1902 includes circuitry 1920 configured to implement code stored in the computer-readable medium / memory 1912. In some aspects, the circuitry 1920 is coupled to the processor 1904 and / or the computer-readable medium / memory 1912 via the bus 1906. For example, the circuitry 1920 includes circuitry 1922 for accessing (or obtaining), circuitry 1924 for transmitting (or outputting), circuitry 1926 for converting, or any combination thereof.

[0168]

[0163] In some examples, the means for transmitting or sending (or the means for outputting to transmit) may include the transceiver 254 and / or the antenna 252 of the UE 120 illustrated in FIG. 2, and / or the transceiver 1908 and the antenna 1910 of the communication device 1900 of FIG. 19.

[0169] In some cases, a device may have an interface (means for outputting) for outputting signals and / or data for transmission, for example, without actually transmitting the signals and / or data. For example, a processor may output signals and / or data to a radio frequency (RF) front end for transmission via a bus interface. Similarly, a device may have an interface (means for acquiring) for acquiring signals and / or data received from another device, without actually receiving the signals and / or data. For example, a processor may acquire (or receive) signals and / or data from an RF front end for reception via a bus interface. In various aspects, the RF front end may include various components, including transmit and receive processors, transmit and receive MIMO processors, modulators, demodulators, etc., such as those depicted in the example of FIG. 2.

[0170]

[0165] In some examples, the means for accessing and / or the means for converting may include various processing system components such as, for example, processor 1904 of FIG. 19 or aspects of UE 120 depicted in FIG. 2, including receive processor 258, transmit processor 264, TX MIMO processor 266, and / or controller / processor 280.

[0171] Exemplary Embodiments

[0166] Implementation examples are described in the numbered clauses below.

[0172]

[0167] Aspect 1: A method of wireless communication by a wireless device, the method comprising: accessing a radio frequency (RF) exposure map associated with at least one antenna of the wireless device, the RF exposure map including a representation of maximum RF exposure for a region of the RF exposure map; and transmitting a signal from the at least one antenna at a transmit power that complies with RF exposure limits determined at least in part based on the RF exposure map.

[0173]

[0168] Aspect 2: The method of aspect 1, wherein the RF exposure map represents RF exposure contributions from multiple antennas of a wireless device.

[0174]

[0169] Aspect 3: The method described in aspect 2, wherein the RF exposure map represents RF exposure contributions arranged in at least two dimensions.

[0175]

[0170] Aspect 4: The method of aspect 2 or 3, wherein the RF exposure contribution spans a range of frequencies.

[0176]

[0171] Aspect 5: The method of aspect 4, wherein the frequency range includes a sub-6 GHz band, a millimeter wave band, or a combination thereof.

[0177]

[0172] Aspect 6: The method of aspect 4 or 5, wherein the RF exposure contribution includes a first RF exposure contribution from a sub-6 GHz band and a second RF exposure contribution from a millimeter wave band.

[0178]

[0173] Aspect 7: The method of any one of aspects 1 to 6, wherein the RF exposure map represents RF exposure contributions across multiple surfaces of the wireless device.

[0179]

[0174] Aspect 8: The method of any one of aspects 1 to 7, wherein the RF exposure map represents RF exposure contributions from at least one antenna of the wireless device to one or more RF exposure scenarios.

[0180]

[0175] Aspect 9: A method according to any one of aspects 1 to 8, wherein the region is a sub-region of a larger exposure region associated with at least one antenna, the region represents one or more points of the larger exposure region associated with at least one antenna, or the region represents one or more values ​​of RF exposure contribution associated with at least one antenna.

[0181]

[0176] Aspect 10: A method according to any one of aspects 1 to 9, wherein the representation of maximum RF exposure for the area enables determination of the transmit power of at least one antenna to ensure compliance with RF exposure limits.

[0182]

[0177] Embodiment 11: A method according to any one of embodiments 1 to 10, wherein the RF exposure map comprises a representation of maximum RF exposure for each of a plurality of regions comprising the region.

[0183]

[0178] Aspect 12: The method of any one of aspects 1 to 11, further comprising determining transmit power using back-off information applied to the RF exposure map.

[0184]

[0179] Aspect 13: A method according to any one of aspects 1 to 12, wherein accessing an RF exposure map includes accessing an RF exposure map from among a plurality of RF exposure maps, each of the RF exposure maps representing a different exposure scenario or a different set of exposure scenarios for the wireless device.

[0185]

[0180] Aspect 14: The method of aspect 13, wherein each of the RF exposure maps has a different combination of one or more active antennas among the plurality of antennas of the wireless device.

[0186]

[0181] Aspect 15: A method according to any one of aspects 1 to 15, further comprising: obtaining a total transmit power for a past time interval within a time window associated with an RF exposure limit; determining an interim transmit power for a future time interval within the time window; converting the sum of the interim transmit power and the total transmit power into a time-averaged RF exposure value for the time window based on an RF exposure map; and adjusting the interim transmit power so that the time-averaged RF exposure value meets the RF exposure limit; and transmitting the signal includes transmitting the signal at a transmit power that is less than or equal to the adjusted interim transmit power that meets the RF exposure limit.

[0187]

[0182] Aspect 16: The method of any one of aspects 1 to 15, wherein the RF exposure limit comprises a time-averaged specific absorption rate (SAR) limit, a time-averaged power density (PD) limit, or any combination thereof.

[0188]

[0183] Aspect 17: A method for generating a radio frequency (RF) exposure map, comprising: obtaining a first RF exposure map associated with at least one antenna of a wireless device; and converting the first RF exposure map into a second RF exposure map that is compressed compared to the first RF exposure map.

[0189]

[0184] Aspect 18: The method of aspect 17, wherein converting the first RF exposure map includes using the first RF exposure map to generate a lookup table of exposure contributions across different regions.

[0190]

[0185] Aspect 19: A method described in aspect 17 or 18, further comprising: accessing a second RF exposure map associated with at least one antenna of the wireless device, the second RF exposure map including a representation of maximum RF exposure for the region; and transmitting a signal from the at least one antenna at a transmit power that complies with an RF exposure limit determined at least in part based on the second RF exposure map.

[0191]

[0186] Aspect 20: The method of aspect 19, wherein a representation of maximum RF exposure for an area enables determination of the transmit power of at least one antenna to ensure compliance with RF exposure limits.

[0192]

[0187] Aspect 21: A method described in any one of aspects 17 to 20, wherein obtaining the first RF exposure map includes obtaining a plurality of RF exposure maps, each RF exposure map representing an RF distribution for a different antenna, and combining the plurality of RF exposure maps to form the first RF exposure map.

[0193]

[0188] Aspect 22: A method described in any one of aspects 17 to 21, wherein the first RF exposure map includes normalized RF exposure contributions from multiple antennas of the wireless device.

[0194]

[0189] Aspect 23: A method described in any one of aspects 17 to 22, wherein the first RF exposure map indicates RF exposure contributions across one or more surfaces of the wireless device from multiple antennas of the wireless device.

[0195]

[0190] Aspect 24: The method described in aspect 23, wherein the first RF exposure map includes a representation of RF exposure contributions arranged in at least two dimensions.

[0196]

[0191] Aspect 25: A method described in any one of aspects 17 to 24, wherein converting the first RF exposure map into a second RF exposure map includes segmenting the first RF exposure map into a plurality of regions, selecting for each region a maximum RF exposure value from a plurality of values ​​in the respective region, and generating the second RF exposure map as the selected maximum RF exposure value in the region.

[0197]

[0192] Aspect 26: The method described in aspect 25, wherein converting the first RF exposure map into a second RF exposure map further includes determining a total normalized composite RF exposure map for multiple antennas based on a backoff factor and the first RF exposure map at a reduced resolution, and re-segmenting the first RF exposure map into multiple regions until the backoff factor meets a threshold for calculating the total normalized composite RF exposure map at the full resolution of the first RF exposure map.

[0198]

[0193] Aspect 27: A method according to any one of aspects 17 to 26, wherein obtaining a first RF exposure map includes combining multiple RF exposure maps to form a first RF exposure map and converting the first RF exposure map into a second RF exposure map, wherein the converting includes segmenting the first RF exposure map into multiple regions and, for each of the regions, selecting a maximum RF exposure value from among multiple values ​​in the respective region and determining a total normalized composite RF exposure map for the multiple antennas based on a backoff factor and the selected maximum RF exposure value in the region and re-segmenting the first RF exposure map into multiple regions until the backoff factor meets a threshold for calculating the total normalized composite RF exposure map at the full resolution of the first RF exposure map.

[0199]

[0194] Aspect 28: An apparatus comprising one or more memories that collectively store executable instructions and one or more processors coupled to the one or more memories, wherein the one or more processors are collectively configured to execute the executable instructions, and the executable instructions cause the apparatus to perform a method according to any one of aspects 1 to 27.

[0200]

[0195] Embodiment 29: An apparatus comprising means for carrying out the method according to any one of embodiments 1 to 27.

[0201]

[0196] Aspect 30: A non-transitory computer-readable medium comprising computer-executable instructions that, when executed by one or more processors of a processing system, cause the processing system to perform a method according to any one of aspects 1 to 27.

[0202] Aspect 31: A computer program product embodied on a computer-readable storage medium comprising code for performing the method according to any one of aspects 1 to 27.

[0203] 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 covers 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 a new wireless communications technology under development.

[0204] In 3GPP, the term "cell" can refer to a coverage area of ​​a Node B (NB) and / or an 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 transmission reception 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 that have an association with the femtocell (e.g., UEs in a Closed Subscriber Group (CSG), UEs of users in the home, etc.). A BS for a macrocell may be referred to as a macro BS. A BS for a picocell may be referred to as a pico BS. A BS for a femtocell may be referred to as a femto BS or a home BS.

[0205] A UE may be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a customer premises equipment (CPE), a mobile phone, a smartphone, a personal digital assistant (PDA), a wireless modem, a wireless device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or equipment, a biometric sensor / device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicle component or sensor, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate over a wireless medium or a wired medium. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, 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 to a network (e.g., a wide area network such as the Internet or a cellular network) or connectivity to a 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.

[0206] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication between some or all devices and equipment within the entity's service 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 use the resources allocated by the scheduling entity. A base station is not the only entity that can 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 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.

[0207]

[0202] The methods disclosed herein include one or more steps or actions for achieving the method. The steps and / or actions of those 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 of specific steps and / or actions and / or the use of those steps and / or actions may be modified without departing from the scope of the claims.

[0208] As used herein, "processor," "at least one processor," or "one or more processors" generally refers to a single processor configured to perform one or more operations, or to multiple processors configured to collectively perform one or more operations. In the case of multiple processors, performance of one or more operations may be divided among different processors, but one processor may perform multiple operations and multiple processors may collectively perform a single operation. Similarly, "memory," "at least one memory," or "one or more memories" generally refers to a single memory configured to store data and / or instructions, or to multiple memories configured collectively to store data and / or instructions.

[0209] 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. By way of 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 having multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other arrangement of a, b, and c).

[0210] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" can include calculating, computing, processing, deriving, generating, investigating, looking up (e.g., looking up in a table, database, or another data structure), ascertaining, and the like. "Determining" can also include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. "Determining" can also include resolving, selecting, choosing, establishing, and the like.

[0211] 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 language of the claims. Reference to an element in the singular does not mean "one and only one," unless expressly stated otherwise, but rather "one or more." Unless otherwise specified, 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 intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be made public, regardless of whether such disclosure is expressly recited in the claims. No element of a claim 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."

[0212] 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, when operations are illustrated in figures, the operations may have corresponding equivalent means-plus-function components that are similarly numbered.

[0213] 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, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0214]

[0209] When implemented in hardware, an exemplary hardware configuration may comprise a processing system within 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 of the processing system and overall design constraints. The bus may link various circuits together, including a processor, a machine-readable medium, and a bus interface. 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 circuit configurations capable of executing software. Those skilled in the art will recognize how to best implement the described functionality for a processing system depending on the particular application and the overall design constraints imposed on the overall system.

[0215]

[0210] 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 shall be broadly construed to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media includes both computer storage media and communication media, including any medium that facilitates transfer of a computer program from one place to another. A processor may be responsible for general processing, including managing a bus and executing software modules stored on the machine-readable storage medium. A 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. By way of example, machine-readable media may include a transmission line, a carrier wave modulated by data, and / or a computer-readable storage medium with stored 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 is the case with 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.

[0216] A software module may include a single instruction or multiple instructions and may be distributed across several different code segments, among different programs, and across multiple storage media. A computer-readable medium may include several software modules. A software module includes 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 may 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 to the functionality of a software module below, it will be understood that such functionality is implemented by the processor upon executing instructions from that software module.

[0217]

[0212] 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 disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically and discs reproduce data optically using lasers. Thus, in some aspects a computer-readable medium may comprise a non-transitory computer-readable medium (e.g., tangible media). Additionally, in other aspects a computer-readable medium may comprise a transitory computer-readable medium (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

[0218]

[0213] Accordingly, certain aspects may include computer program products for performing the operations presented herein. For example, such computer program products may include a computer-readable medium having stored (and / or encoded) instructions, e.g., for performing the operations described herein and illustrated in Figures 6, 14, 17, and / or 18, executable by one or more processors to perform the operations described herein.

[0219] Furthermore, it should be understood 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 devices 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.) such that a user terminal and / or base station may acquire the various methods by coupling or providing the storage means to the device. Furthermore, any other suitable technique for providing the methods and techniques described herein to a device may be utilized.

[0220]

[0215] It is to be understood that the claims are not limited to the precise configuration and components illustrated 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.

Claims

1. 1. A method of wireless communication by a wireless device, comprising: accessing a radio frequency (RF) exposure map associated with at least one antenna of the wireless device, the RF exposure map including a representation of a maximum RF exposure for a region of the RF exposure map; transmitting a signal from the at least one antenna at a transmit power that complies with RF exposure limits, the transmit power being determined based at least in part on the RF exposure map; A method comprising:

2. The method of claim 1 , wherein the RF exposure map represents RF exposure contributions from multiple antennas of the wireless device.

3. The method of claim 2 , wherein the RF exposure map represents the RF exposure contributions arranged in at least two dimensions.

4. The method of claim 2 , wherein the RF exposure contribution spans a range of frequencies.

5. The method of claim 4 , wherein the range of frequencies includes a sub-6 gigahertz (GHz) band, a millimeter wave (mmWave) band, or a combination thereof.

6. 5. The method of claim 4, wherein the RF exposure contributions include a first RF exposure contribution from a sub-6 gigahertz (GHz) band and a second RF exposure contribution from a millimeter-wave (mm-wave) band.

7. The method of claim 1 , wherein the RF exposure map represents RF exposure contributions across multiple surfaces of the wireless device.

8. The method of claim 1 , wherein the RF exposure map represents RF exposure contributions from at least one antenna of the wireless device to one or more RF exposure scenarios.

9. 2. The method of claim 1, wherein the region represents (i) one or more points of a larger exposure region associated with the at least one antenna, or (ii) one or more values ​​of an RF exposure contribution associated with the at least one antenna.

10. 2. The method of claim 1, wherein the representation of the maximum RF exposure for the area enables determination of the transmit power of the at least one antenna to ensure compliance with the RF exposure limits.

11. The method of claim 1 , wherein the RF exposure map includes the representation of the maximum RF exposure for each of a plurality of regions that include the region.

12. The method of claim 1 , further comprising determining the transmit power using back-off information applied to the RF exposure map.

13. 10. The method of claim 1, wherein accessing the RF exposure map comprises accessing the RF exposure map from among a plurality of RF exposure maps, each of the RF exposure maps representing a different exposure scenario or a different set of exposure scenarios for the wireless device.

14. The method of claim 13 , wherein each of the RF exposure maps has a different combination of one or more active antennas among a plurality of antennas of the wireless device.

15. obtaining a total transmit power for a past time interval within a time window associated with the RF exposure limit; determining a tentative transmit power for a future time interval within the time window; converting the sum of the interim transmit power and the total transmit power into a time-averaged RF exposure value for the time window based on the RF exposure map; adjusting the interim transmit power such that the time-averaged RF exposure value meets the RF exposure limit; 10. The method of claim 1, further comprising: transmitting the signal at the transmit power that is less than or equal to the adjusted interim transmit power that meets the RF exposure limit.

16. 10. The method of claim 1, wherein the RF exposure limit comprises a time-averaged specific absorption rate (SAR) limit, a time-averaged power density (PD) limit, or any combination thereof.

17. 1. A method for generating a radio frequency (RF) exposure map, comprising: obtaining a first RF exposure map associated with at least one antenna of the wireless device; converting the first RF exposure map into a second RF exposure map that is compressed relative to the first RF exposure map; A method comprising:

18. 20. The method of claim 17, wherein transforming the first RF exposure map comprises using the first RF exposure map to generate a lookup table of exposure contributions across different regions.

19. accessing the second RF exposure map associated with the at least one antenna of the wireless device, the second RF exposure map including a representation of a maximum RF exposure for a region; transmitting a signal from the at least one antenna at a transmit power that complies with RF exposure limits, determined based at least in part on the second RF exposure map; 20. The method of claim 17, further comprising:

20. 20. The method of claim 19, wherein the representation of the maximum RF exposure for the region enables determination of the transmit power of the at least one antenna to ensure compliance with the RF exposure limits.

21. obtaining the first RF exposure map; obtaining a plurality of RF exposure maps, each of the RF exposure maps representing an RF distribution for a different antenna; combining the plurality of RF exposure maps to form the first RF exposure map; 18. The method of claim 17, comprising:

22. 20. The method of claim 17, wherein the first RF exposure map comprises normalized RF exposure contributions from multiple antennas of the wireless device.

23. 20. The method of claim 17, wherein the first RF exposure map indicates RF exposure contributions across one or more surfaces of the wireless device from multiple antennas of the wireless device.

24. 24. The method of claim 23, wherein the first RF exposure map comprises a representation of the RF exposure contributions arranged in at least two dimensions.

25. converting the first RF exposure map to the second RF exposure map; Segmenting the first RF exposure map into a plurality of regions; selecting, for each of the regions, a maximum RF exposure value from among a plurality of values ​​in the respective region; generating the second RF exposure map as the selected maximum RF exposure value in the region; 18. The method of claim 17, comprising:

26. converting the first RF exposure map to the second RF exposure map; determining a total normalized composite RF exposure map for a plurality of antennas based on back-off factors and the first RF exposure map at a reduced resolution; re-segmenting the first RF exposure map into the plurality of regions until the back-off factor meets a threshold for calculating the total normalized composite RF exposure map at the full resolution of the first RF exposure map; 26. The method of claim 25, further comprising:

27. obtaining the first RF exposure map; combining a plurality of RF exposure maps to form the first RF exposure map; converting the first RF exposure map to the second RF exposure map; wherein said converting comprises: Segmenting the first RF exposure map into a plurality of regions; selecting, for each of the regions, a maximum RF exposure value from among a plurality of values ​​in the respective region; determining a total normalized composite RF exposure map for a plurality of antennas based on a back-off factor and the selected maximum RF exposure value in the region; re-segmenting the first RF exposure map into the plurality of regions until the back-off factor meets a threshold for calculating the total normalized composite RF exposure map at the full resolution of the first RF exposure map; 18. The method of claim 17, comprising:

28. 1. An apparatus for wireless communication, comprising: one or more memories that collectively store executable instructions; one or more processors coupled to the one or more memories; wherein the one or more processors are collectively configured to execute the executable instructions, the executable instructions causing the device to: accessing a radio frequency (RF) exposure map associated with at least one antenna of the device, the RF exposure map including a representation of maximum RF exposure for a region of the RF exposure map; controlling transmission of signals from the at least one antenna at a transmit power that complies with RF exposure limits, determined at least in part based on the RF exposure map. Device.

29. 1. An apparatus for generating a radio frequency (RF) exposure map, comprising: one or more memories that collectively store executable instructions; one or more processors coupled to the one or more memories; wherein the one or more processors are collectively configured to execute the executable instructions, the executable instructions causing the device to: obtaining a first RF exposure map associated with at least one antenna of the wireless device; converting the first RF exposure map into a second RF exposure map that is compressed relative to the first RF exposure map; Device.

30. the one or more processors are further collectively configured to execute the executable instructions, the executable instructions causing the device to: accessing the second RF exposure map associated with the at least one antenna of the wireless device, the second RF exposure map including a representation of maximum RF exposure for a region; causing the at least one antenna to transmit a signal at a transmit power that complies with RF exposure limits determined based at least in part on the second RF exposure map.

30. The apparatus of claim 29.

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