Radio frequency exposure evaluation per surface

Abstract

Certain aspects of the present disclosure provide techniques and apparatus for radio frequency exposure assessment per surface. A method of wireless communication by a wireless device includes accessing radio frequency (RF) exposure information associated with different surfaces among a plurality of surfaces of the wireless device; and transmitting a signal at a transmit power determined based at least in part on the RF exposure information and the RF exposure limit.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 18 / 472,070, filed on September 21, 2023, which claims the benefit of and priority to U.S. application serial number 63 / 376,964, filed on September 23, 2022, and the entire contents of both applications are incorporated by reference for all purposes. Background Art Technical Field

[0003] Aspects of the present disclosure relate to wireless communications and, more particularly, to radio frequency (RF) exposure compliance.

[0004] Description of Related Technology

[0005] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, broadcasting, etc. Modern wireless devices, such as cellular phones, are often required to meet radio frequency (RF) exposure limits set by certain government and international standards and regulations. To ensure compliance with the standards, such devices currently must undergo an extensive certification process before they can be placed on the market. To ensure that wireless devices comply with RF exposure limits, technologies have been developed that enable wireless devices to assess RF exposure from the wireless device and adjust the transmit power of the wireless device accordingly to comply with the RF exposure limits. Summary of the invention

[0006] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desirable characteristics. Without limiting the scope of the present disclosure as expressed in the appended claims, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," one will understand how the features of the present disclosure provide advantages, including improved wireless communication performance.

[0007] 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 radio frequency (RF) exposure information associated with different surfaces among a plurality of surfaces of the wireless device. The method also includes transmitting a signal at a transmit power determined at least in part based on the RF exposure information and an RF exposure limit.

[0008] Certain aspects of the subject matter described in this disclosure may be implemented in a device for wireless communication. The device generally includes one or more memories that collectively store computer-executable instructions. The device also includes one or more processors that are coupled to the one or more memories. The one or more processors are collectively configured to execute these computer-executable instructions so that the device performs operations. The operations include accessing radio frequency (RF) exposure information associated with different surfaces among multiple surfaces of the device. The operations also include sending a signal at a transmit power determined at least in part based on the RF exposure information and an RF exposure limit.

[0009] Certain aspects of the subject matter described in this disclosure can be implemented in an apparatus for wireless communication. The apparatus generally includes components for accessing radio frequency (RF) exposure information associated with different surfaces among a plurality of surfaces of the apparatus. The apparatus also includes components for transmitting a signal at a transmit power determined at least in part based on the RF exposure information and an RF exposure limit.

[0010] Certain aspects of the subject matter described in this disclosure may be implemented in a non-transitory computer-readable medium having stored thereon instructions for: accessing radio frequency (RF) exposure information associated with different surfaces among a plurality of surfaces of a wireless device; and transmitting a signal at a transmit power determined at least in part based on the RF exposure information and an RF exposure limit.

[0011] Other aspects provide: an apparatus operable to, configured to, or otherwise adapted to perform any one or more of the foregoing methods and / or those 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 foregoing methods and those described elsewhere herein; a computer program product embodied on a computer-readable storage medium, the computer program product comprising code for performing the foregoing methods and those described elsewhere herein; and / or an apparatus comprising components for performing the foregoing methods and those described elsewhere herein. By way of example, an apparatus may include a processing system, a device having a processing system, or a processing system cooperating through one or more networks.

[0012] To achieve the aforementioned and related purposes, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain exemplary features of the one or more aspects. However, these features indicate only some of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order that the above-mentioned features of the present disclosure can be understood in detail, a more specific description briefly summarized above can be obtained by referring to some aspects illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only certain typical aspects of the present disclosure and are therefore not to be considered as limiting the scope thereof, as the specification may admit to other equally effective aspects.

[0014] Figure 1 is a block diagram conceptually illustrating an example wireless communication network.

[0015] Figure 2 is a block diagram conceptually illustrating a design of an example base station (BS) and user equipment (UE).

[0016] Figure 3 is a block diagram of an example radio frequency (RF) transceiver.

[0017] Figure 4A , Figure 4B and Figure 4C is a graph illustrating an example of transmit power over time complying with time-averaged RF exposure limits.

[0018] Figure 5 An isometric view of multiple antennas arranged in various locations of a wireless device is illustrated.

[0019] Figure 6 An example table of normalized specific absorbance ratios for specific surfaces and / or locations is illustrated.

[0020] Fig. 7A An example table illustrating normalized power density ratios for a particular surface for each antenna array is shown.

[0021] Figure 7B An example table illustrating normalized power density ratios per beam for a particular surface.

[0022] Figure 8 is a flow diagram illustrating example operations for wireless communications by a wireless device in accordance with certain aspects of the present disclosure.

[0023] Fig. 9 Illustrated is a communications device (eg, UE) that may include various components configured to perform operations for the techniques disclosed herein in accordance with certain aspects of the present disclosure.

[0024] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation. DETAILED DESCRIPTION

[0025] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for per-surface radio frequency (RF) exposure assessment of wireless devices.

[0026] In some cases, the wireless communication device may use a time averaging operation to assess RF exposure compliance. The wireless device may perform an RF exposure assessment of past RF exposures within a given time window to determine a maximum allowed transmit power for future time intervals within the time window. The time averaging operation may track the normalized RF exposure history (e.g., transmit power divided by the maximum time average transmit power limit) within the time window for each radio component, and the wireless device may sum the normalized RF exposures of all active radio components in a simultaneous transmit scenario.

[0027] In some cases, summing the normalized RF exposure associated with the radio components may use the worst-case exposure for a specific surface associated with each of the radio components. This time-averaging operation assumes that the radio components in the simultaneous transmission scenario have the worst-case exposure on the same surface, even when the worst-case exposure for one radio component may occur on a different surface than another radio component. For example, a radio component may exhibit its worst-case exposure (e.g., highest exposure) on the top surface of the wireless device (e.g., where the radio component is arranged), and another radio component may exhibit its worst-case exposure on the left surface of the wireless device (e.g., where the other radio component is arranged). The time-averaging operation may use the worst-case exposure for each of the radio components, regardless of the surface on which the exposure occurs. In a body-worn exposure scenario (e.g., when the mobile phone is stored in a shirt pocket or a trouser pocket), RF exposure may occur from the front surface, back surface, left surface, right surface, top surface, and / or bottom surface of the wireless device. Different radio access technologies, frequency bands, antennas (or antenna arrays), and exposure scenarios (eg, head, body, limb, or hotspot scenarios) may have worst case exposure on different surfaces.

[0028] Various aspects of the present disclosure provide an apparatus and method for evaluating the RF exposure of each surface of a wireless device. The total time-averaged RF exposure of multiple radio components can be evaluated for each exposed surface of the wireless device. For time-averaged RF exposure compliance, the wireless device can track the historical RF exposure of multiple radio components from each surface of the wireless device. The wireless device can determine the maximum allowable transmit power for future time intervals based on the RF exposure evaluated per surface. For example, the wireless device can select the minimum value of the transmit power among the values ​​determined for each surface.

[0029] The apparatus and methods described herein for assessing RF exposure per surface may be useful for improving wireless communication performance (e.g., improving signal quality at a receiver, reducing latency, increasing throughput, etc.). For example, the RF exposure assessment per surface may provide an accurate assessment of the RF exposure occurring at a particular surface on a wireless device, thereby allowing the wireless device to assign more exposure margin to certain transmissions.

[0030] As used herein, a radio may refer to one or more active frequency bands, transceivers, and / or radio access technologies (RATs) used for wireless communications (e.g., code division multiple access (CDMA), long term evolution (LTE), new radio (NR), IEEE 802.11, Bluetooth, satellite, near field communication (NFC), peer-to-peer (P2P), vehicle-to-everything (V2X), etc.). For example, for uplink carrier aggregation in LTE and / or NR, each of the active component carriers used for wireless communications may be considered a separate radio. Similarly, multi-band transmissions for IEEE 802.11 communications may be considered a separate radio for each frequency band (e.g., 2.4 GHz, 5 GHz, or 6 GHz).

[0031] The following description provides an example of RF exposure compliance in a communication system, without limiting the scope, applicability or examples set forth in the claims. Without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Various examples may omit, replace or add various procedures or components as appropriate. For example, the described method may be performed in a different order than described, and various steps may be added, omitted or combined. In addition, features equivalent to some example descriptions may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such devices or methods practiced using other structures, functionalities, or structures and functionalities that supplement or replace the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of the present claims. The word "exemplary" is used herein to mean "used as an example, instance, or illustration". Any aspect described herein as "exemplary" is not necessarily interpreted as being preferred or having advantages over other aspects.

[0032] Generally speaking, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. RAT may also be referred to as a radio technology, an air interface, etc. Frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs, or may support multiple RATs.

[0033] The techniques described herein can be used for various wireless networks and radio technologies. Although various aspects may be described herein using terms commonly associated with 3G, 4G, and / or new radio (e.g., 5G NR) wireless technologies, various aspects of the present disclosure may be applied to communication systems based on other generations and / or to wireless technologies such as 802.11, 802.15, etc.

[0034] NR access can support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or more), millimeter wave (mmWave) targeting high carrier frequency (e.g., 24 GHz to 53 GHz or more), massive machine type communication MTC (mMTC) targeting non-backward compatible machine type communication (MTC) technology, and / or mission critical services targeting ultra-reliable low latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmit time intervals (T TIs) to meet corresponding quality of service (QoS) requirements. In addition, these services can coexist in the same subframe. NR supports beamforming and can dynamically configure beam directions. Multiple input multiple output (MIMO) transmission using precoding can also be supported as multi-layer transmission. Aggregation of multiple cells can be supported.

[0035] Example Wireless Communications Networks and Devices

[0036] Figure 1 An example wireless communication network 100 is illustrated in which aspects of the present disclosure may be performed. For example, the wireless communication network 100 may be a 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 one or more of the IEEE standards such as the 802.11 standard. Figure 1 As shown, in accordance with aspects of the present disclosure, UE 120a includes an RF exposure manager 122 that ensures RF exposure compliance using RF exposure assessments for each of a plurality of surfaces of UE 120a.

[0037] like Figure 1As illustrated in , the wireless communication network 100 may include multiple BSs 110a-110z (each also individually referred to herein as BS 110, or collectively referred to as BS 110) and other network entities. BS 110 may provide communication coverage for a specific geographic area (sometimes referred to as a "cell"), which may be stationary or may move according to the location of the mobile BS 110. In some examples, BS 110 may be interconnected with each other and / or connected to one or more other BSs or network nodes (not shown) in the wireless communication network 100 through various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.) using any suitable transport network. Figure 1 In the example shown, BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more cells.

[0038] BS 110 communicates with UEs 120a-120y (each also individually referred to herein as UE 120 or collectively referred to as UE 120) in the wireless communication network 100. 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) (also referred to as a relay, etc.) that receives transmissions of data and / or other information from an upstream station (e.g., BS 110a or UE 120r) and transmits the transmissions of the data and / or other information to a downstream station (e.g., UE 120 or BS 110), or relays transmissions between UEs 120 to facilitate communication between devices.

[0039] The network controller 130 may communicate with a collection of BSs 110 and provide coordination and control (e.g., via backhaul) for these BSs 110. In some cases, such as in a 5G NR system, the network controller 130 may include a centralized unit (CU) and / or a distributed unit (DU). In various aspects, the network controller 130 may communicate 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, unified data management, application functions, network open functions, network repository functions, network slice selection functions, etc.

[0040] In the present disclosure, the term "beam" may be used in various contexts. A beam may be used to refer to a set of gains and / or phases (e.g., precoding weights or co-phasing weights) applied to antenna elements in a UE and / or BS for transmission or reception. The term "beam" may also refer to an antenna or radiation pattern of a signal transmitted when the gain and / or phase are applied to the antenna elements. Other references to a beam may include one or more characteristics or parameters associated with an antenna (radiation) pattern, such as angle of arrival (AoA), angle of departure (AoD), gain, phase, directivity, beamwidth, beam direction in azimuth and elevation (relative to a reference plane), peak-to-sidelobe ratio, or antenna ports associated with the antenna (radiation) pattern. The term "beam" may also refer to an associated number and / or configuration of antenna elements (e.g., a uniform linear array, a uniform rectangular array, or other uniform array).

[0041] Figure 2 1 and 120a (eg, Figure 1 Example components of a wireless communication network 100).

[0042] At BS 110a, a transmit processor 220 may receive data from a data source 212 and control information from a 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).

[0043] The processor 220 may process (e.g., encode and symbol map) 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., pre-decoding) on ​​data symbols, control symbols, and / or reference symbols (where applicable), and may provide an output symbol stream to a modulator (MOD) in a transceiver 232a-232t. Each modulator 232a-232t in the transceiver may process a respective output symbol stream (e.g., for orthogonal frequency division multiplexing (OFDM), etc.) to obtain an output sample stream. Each modulator in the transceiver 232a-232t may further process (e.g., transform to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. Downlink signals from transceivers 232a-232t may be transmitted via antennas 234a-234t, respectively.

[0044] At UE 120a, antennas 252a-252r may receive downlink signals from BS110a and may provide received signals to transceivers 254a-254r, respectively. Transceivers 254a-254r may condition (e.g., filter, amplify, downconvert, and digitize) the corresponding received signals to obtain input samples. Each demodulator (DEMOD) in transceivers 232a-232t may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. MIMO detector 256 may obtain received symbols from all demodulators in transceivers 254a-254r, perform MIMO detection on the received symbols (where applicable), and provide detected symbols. Receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120a to data sink 260, and provide decoded control information to controller / processor 280.

[0045] 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 reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 264 may be pre-decoded by a TX MIMO processor 266 (if applicable), further processed by a modulator (MOD) in the transceivers 254a-254r (e.g., for single carrier frequency division multiplexing (SC-FDM), etc.), and transmitted to the BS 110a. At BS 110a, the uplink signal from UE 120a may be received by antenna 234, processed by demodulators in transceivers 232a-232t, detected by MIMO detector 236 (if applicable), and further processed by receive processor 238 to obtain decoded data and control information transmitted 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.

[0046] Memories 242 and 282 may store data and program codes for BS 110a and UE 120a, respectively.A scheduler 244 may schedule UEs for data transmission on the downlink and / or uplink.

[0047] The antenna 252, processors 266, 258, 264 and / or controller / processor 280 of the UE 120a and / or the antenna 234, processors 220, 230, 238 and / or controller / processor 240 of the BS 110a may be used to perform the various techniques and methods described herein. Figure 2 As shown, the controller / processor 280 of the UE 120a has an RF exposure manager 281 that represents the RF exposure manager 122, in accordance with aspects described herein. Although shown at the controller / processor, other components of the UE 120a and BS 110a may be used to perform the operations described herein.

[0048] NR can use orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) on the uplink and downlink. NR can use time division duplex (TDD) to support half-duplex operation. OFDM and single carrier frequency division multiplexing (SC-FDM) divide the system bandwidth into multiple orthogonal subcarriers, which are also commonly referred to as tones, frequency bands, etc. Each subcarrier can be modulated with data. Modulation symbols can be transmitted in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers can depend on the system bandwidth. The system bandwidth can also be divided into multiple subbands. For example, one subband can cover multiple resource blocks (RBs).

[0049] Although the reference Figure 1 and Figure 2 UE 120a is described as communicating with a BS and / or within a network, but UE 120a may be configured to communicate / transmit directly to another UE 120 or directly to another wireless device without relaying the communication through a network. Figure 2 The BS 110 a illustrated in FIG. 4 and described above is an example of another UE 120 .

[0050] Example RF Transceiver

[0051] Figure 3 is a block diagram of an example RF transceiver circuit 300 according to certain aspects of the present disclosure. The RF transceiver circuit 300 includes at least one transmit (TX) path 302 (also referred to as a transmit chain) for transmitting signals via one or more antennas 306 and at least one receive (RX) path 304 (also referred to as a receive chain) for receiving signals via antenna 306. When TX path 302 and RX path 304 share antenna 306, these paths can be connected to the antenna via interface 308, which can include any of a variety of suitable RF devices, such as switches, duplexers, diplexers, multiplexers, etc.

[0052] Receiving an in-phase (I) or quadrature (Q) baseband analog signal from a digital-to-analog converter (DAC) 310, the TX path 302 may include a baseband filter (BBF) 312, a mixer 314, a driver amplifier (DA) 316, and a power amplifier (PA) 318. The BBF 312, the mixer 314, and the DA 316 may be included in one or more radio frequency integrated circuits (RFICs). For some implementations, the PA 318 may be external to the RFIC.

[0053] The BBF 312 filters the baseband signal received from the DAC 310, and the mixer 314 mixes the filtered baseband signal with a transmit local oscillator (LO) signal to convert the baseband signal of interest to a different frequency (e.g., upconvert from baseband to radio frequency). This frequency conversion process produces sum and difference frequencies between the LO frequency and the frequency of the baseband signal of interest. The sum and difference frequencies are referred to as beat frequencies. The beat frequencies are typically in the RF range, so that the signal output by the mixer 314 is typically an RF signal, which may be amplified by the DA 316 and / or by the PA 318 before being transmitted through the antenna 306. Although one mixer 314 is illustrated, several mixers may be used to upconvert the filtered baseband signal to one or more intermediate frequencies and thereafter upconvert the intermediate frequency signal to a frequency for transmission.

[0054] The RX path 304 may include a low noise amplifier (LNA) 324, a mixer 326, and a baseband filter (BBF) 328. The LNA 324, the mixer 326, and the BBF 328 may be included in one or more RFICs, which may be the same RFIC as the RFIC that includes the TX path components, or may be a different RFIC. The RF signal received via the antenna 306 may be amplified by the LNA 324, and the mixer 326 mixes the amplified RF signal with a receive local oscillator (LO) signal to convert the RF signal of interest to a different baseband frequency (e.g., down-convert). The baseband signal output by the mixer 326 may be filtered by the BBF 328 before being converted to a digital I or Q signal by an analog-to-digital converter (ADC) 330 for digital signal processing.

[0055] Some transceivers may use 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 a TX frequency synthesizer 320, which may be buffered or amplified by an amplifier 322 before being mixed with the baseband signal in mixer 314. Similarly, the receive LO may be generated by an RX frequency synthesizer 332, which may be buffered or amplified by an amplifier 334 before being mixed with the RF signal in mixer 326.

[0056] Controller 336 may direct the operation of RF transceiver circuit 300, such as transmitting signals via TX path 302 and / or receiving signals via RX path 304. 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 components, discrete hardware components, or any combination thereof. Memory 338 may store data and program code for operating RF transceiver circuit 300. Controller 336 and / or memory 338 may include control logic. In some cases, controller 336 may determine the transmit power applied to TX path 302 (e.g., certain gain levels applied at BBF 312, DA 316, and / or PA 318) in compliance with RF exposure limits set by country-specific regulations and / or international standards, as further described herein.

[0057] Example RF Exposure Compliance

[0058] RF exposure can be expressed in terms of the specific absorption rate (SAR), which measures the energy absorbed per unit mass of human tissue and may have units of watts per kilogram (W / kg). RF exposure can also be expressed in terms of power density (PD), which measures the energy absorbed per unit area and may have units of milliwatts per square centimeter (mW / cm 2 ) units. In some cases, maximum permissible exposure (MPE) limits (in the form of PD) may be imposed on wireless devices using transmit frequencies above 6 GHz. MPE limits are area-based exposure regulatory metrics, such as energy density limits, which are defined as the number X (watts per square meter (W / m2) averaged over a defined area and time-averaged over a frequency-dependent time window. 2 )) to prevent hazardous human exposure represented by changes in tissue temperature.

[0059] SAR may be used to assess RF exposure for transmission frequencies less than 6 GHz, which covers wireless communication technologies such as 2G / 3G (e.g., CDMA), 4G (e.g., LTE), 5G (e.g., NR in the 6 GHz band), IEEE 802.11ac, etc. PD may be used to assess RF exposure for transmission frequencies above 6 GHz, which covers wireless communication technologies such as IEEE 802.11ad, 802.11ay, 5G in the millimeter wave band, etc. Therefore, different metrics may be used to assess RF exposure for different wireless communication technologies.

[0060] A wireless device (e.g., UE 120) may use multiple wireless communication technologies to send signals simultaneously. For example, a wireless device may use a first wireless communication technology (e.g., 3G, 4G, 5G, etc.) operating at or below 6 GHz and a second wireless communication technology (e.g., millimeter wave 5G in the 24 GHz to 60 GHz band, IEEE 802.11ad or 802.11ay) operating above 6 GHz to send signals simultaneously. In some aspects, a wireless device may use a first wireless communication technology (e.g., 3G, 4G, 5G, IEEE 802.11ac, etc. in the sub-6 GHz band) (where RF exposure is measured in SAR) and a second wireless communication technology (e.g., 5G, IEEE 802.11ad, 802.11ay, etc. in the 24 GHz to 60 GHz band) (where RF exposure is measured in PD) to send signals simultaneously. As used herein, sub-6 GHz frequency bands may include frequency bands from 300 MHz to 6,000 MHz in some examples, and may include frequency bands within the range of 6,000 MHz and / or 7,000 MHz in some examples.

[0061] In some cases, compliance with RF exposure limits may be performed as a time-averaged RF exposure assessment over a specified time window (T) associated with the RF exposure limit (e.g., 2 seconds for mmWave or 60 GHz bands, 100 seconds or 360 seconds for ≤6 GHz bands, etc.).

[0062] Figure 4A 400A is a graph of transmit power (P(t)) over time as it varies within a time window (T) associated with RF exposure limits in accordance with certain aspects of the present disclosure. As an example, during certain transmit opportunities within the time window (T), the instantaneous transmit power may exceed the maximum time-averaged transmit power level P(t). limit That is, the transmission power can be greater than the maximum time average transmission power level P limit In some cases, the UE can P max Send, P max is the maximum transmit power supported by the UE. In some cases, at some transmission opportunities, the UE can be less than or equal to the maximum time-averaged transmit power level P limit The maximum time average transmit power level P limit represents the time-averaged threshold value in terms of transmit power for RF exposure limit within a time window (T), and in some cases, P limit This may be referred to as a maximum time average power level or limit, or in terms of exposure, a maximum time average RF exposure level or limit. Graph 400A also illustrates gaps between transmit bursts, where these gaps represent periods during which no transmission is being output from the device.

[0063] In some cases, the transmit power may be maintained at a maximum time-averaged transmit power level (e.g., P) allowed for RF exposure compliance that enables continuous transmission during the time window. limit ).For example, Figure 4B is a graph 400B of transmit power (P(t)) over time, illustrating a case where the transmit power is limited to P in accordance with certain aspects of the present disclosure. limit As shown in the figure, the UE can follow the RF exposure limit to P limit Send continuously.

[0064] Figure 4C 400C is a graph of transmit power (P(t)) over time illustrating a time-averaged mode that provides reserved power to enable continuous transmission within a time window (T) in accordance with certain aspects of the present disclosure. As shown, the transmit power may be increased from a maximum instantaneous power (P max ) falls back to the reserved power (P reserve ), so that the UE can continue to operate at a lower power (P reserve ) to maintain continuous transmission (e.g., maintain a radio connection with the receiving entity) during the time window. Figure 4C For the time window T, the area of ​​the transmitted power (P(t)) is equal to P limit The area below (such as Figure 4B 100% of the energy (transmitted power or exposure) may be used to account for such areas to maintain compliance with time-averaged RF exposure limits. reserve In the case of max The transmitter is turned off during the remainder of the time window to ensure compliance with time-averaged RF exposure limits. reserve Set to a fixed power used to serve a certain purpose (e.g., to reserve power for some communication). reserve yes Figure 4C P limit half of P max During the duration of P max With P reserve The area between can be equal to P in this time window limit With P reserve The area between. max The transmission duration under P may be referred to as the burst transmission time (or high power duration). When more margin is available in the future (after T seconds), the transmitter may be allowed to transmit again at a higher power (e.g., at P max (sent in short bursts below).

[0065] In some respects, Figure 4C In the time average mode illustrated in FIG, the UE can operate at a power level higher than the average power level but less than P max Although Figure 4C A single transmit burst is illustrated in FIG. 1 , but it should be understood that the UE may alternatively utilize multiple transmit bursts within the time window (T), such as described herein with respect to Figure 4A The transmit bursts may be maintained at a transmit power equal to or lower than P reserve In addition, it should be understood that the transmit power of each transmit burst may vary (within a burst and / or compared to other bursts), and at least a portion of the burst may be above a maximum average power level (e.g., P limit ) power to send.

[0066] Although FIG. 4A to FIG. 4C Continuous transmission within a window, opportunity, burst, etc. is illustrated, but it should be understood that a transmission duty cycle can be implemented. In such a specific implementation, the transmission power may be periodically zero and maintained at a higher level during other parts of the duty cycle (e.g., as FIG. 4A to FIG. 4C As used herein, a duty cycle of a transmission may refer to a portion (e.g., 5 ms) of a particular period (e.g., 500 ms) in 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 change over time, for example due to changes in radio conditions, mobility, and / or user behavior.

[0067] In some cases, the RF exposure of the wireless device may be certified by a regulatory agency (e.g., the Federal Communications Commission (FCC)). Spatial measurements may be made relative to a model (phantom) representing the human body, where the model may be filled with a liquid that simulates human tissue. As discussed above, UE 120 may simultaneously transmit signals using a first technology (e.g., 3G, 4G, IEEE 802.11ac, etc.) and a second technology (e.g., 5G, IEEE 802.11ad, etc.), wherein RF exposure is measured using different metrics for the first technology and the second technology (e.g., SAR for the first technology and PD for the second technology). RF exposure measurements may be performed differently for each transmission scenario and include, for example, electric field measurements using a human body model. Then, RF exposure distributions (simulations and / or measurements) may be generated for each transmit antenna / configuration (beam) on all (or some) evaluation surfaces / positionings of the wireless device at all (or some) positions of the human body model.

[0068] Certain regulations and / or standards for RF exposure compliance may allow for some exceptions to measuring RF exposure. For example, if one or more exclusion criteria are met, RF exposure may not be measured for some surfaces of a wireless device. The FCC allows that SAR measurements may be exempted if the transmit antenna inside the wireless device is located greater than 25 millimeters (mm) from the evaluation surface. For example, when the antenna is located at the bottom surface of the wireless device, SAR measurements at the top surface of the wireless device may not be obtained. For surfaces that meet the exclusion criteria, the wireless device may use default values ​​for RF exposure, such as assuming 0.4 W / kg averaged over one gram of mass on the surface.

[0069] In some cases, an RF exposure distribution associated with a wireless device may provide RF exposure (e.g., SAR) measurements on various surfaces of the wireless device. For example, for a particular transmission scenario (e.g., a particular radio access technology, frequency band, antenna, and / or exposure scenario), the measured 1gSAR values ​​for the front surface, back surface, left surface, right surface, top surface, and bottom surface may be equal to [0.51, 0.41, 1.05, 0.23, XX, 0.71], where XX represents a surface for which RF exposure measurements were not made, e.g., due to some exceptions in the certification process. For another transmission scenario (e.g., a different radio access technology, frequency band, antenna, and / or exposure scenario), the measured 1gSAR values ​​for the corresponding surfaces may be equal to [0.42, 0.63, 0.21, 1.09, XX, 0.67]. The maximum time-averaged transmit power level P for each transmission scenario is determined based on the highest 1gSAR value among all surfaces. limit In this example, the highest 1gSAR value may be 1.05 W / kg for the first transmission scenario and 1.09 W / kg for the second transmission scenario. The maximum time-averaged transmission power level P limit It can be determined as follows:

[0070]

[0071] where in this example, the highest 1 gSAR value may be 1.05 W / kg or 1.09 W / kg; the transmit power level is the measured transmit power obtained during the SAR measurement; and the SAR design goal may be to adjust P limit Factors that can be used to meet RF exposure limits. limit The transmit power level corresponds to the RF exposure level given by the SAR design target.The second SAR design target may be less than or equal to the RF exposure limit.

[0072] To evaluate the time-averaged RF exposure compliance when the wireless device transmits simultaneously in such a transmission scenario, the wireless device may use the maximum time-averaged transmission power level P for the corresponding transmission scenario, even though the normalized exposure is associated with different surfaces of the wireless device. limit Transmitting simultaneously may refer to the wireless device transmitting via multiple radio components and / or antennas (or antenna arrays) in the same time interval associated with the time window of the time average RF exposure limit. The wireless device may track past RF exposure for a given time interval (e.g., 0.5 seconds) according to the following expression:

[0073]

[0074] In this example, TotalNormExposure is the total normalized exposure exhibited by the two antennas; TxPower ant1 and is the past transmit power for a given time interval (e.g., 0.5 seconds) and the maximum time-averaged transmit power associated with the first antenna; and and is the past transmit power for that time interval and the maximum time-averaged transmit power associated with the second antenna. In this example, the wireless device uses the worst-case exposure associated with each of the transmit scenarios, even if these worst-case exposures are presented from different surfaces of the wireless device (e.g., the left surface for ant1 and the right surface for ant2). In some cases, the wireless device may not use normalized exposure values ​​for other surfaces, so that the wireless device only knows the worst-case exposure for evaluating time-averaged RF exposure compliance.

[0075] Example RF exposure assessment per surface

[0076] A multi-mode / multi-band UE has multiple transmit antennas that can transmit simultaneously in the sub-6 GHz band and the frequency band greater than 6 GHz band (such as the millimeter wave band). As described herein, RF exposure for the sub-6 GHz band can be evaluated in terms of SAR, and RF exposure for the frequency band greater than 6 GHz can be evaluated in terms of PD. Due to regulations regarding simultaneous exposure, wireless devices may limit the maximum transmit power for both the sub-6 GHz band and the frequency band greater than 6 GHz. With respect to PD evaluation, the equivalent term to the SAR design target term described above is the PD design target, which may generally be referred to as the RF exposure design target, where RF exposure may represent both SAR or PD or any other RF exposure metric required by regulations and / or standards. limitThe transmit power level may correspond to an RF exposure level given by an RF exposure design target. The RF exposure design target may be less than or equal to the RF exposure limit. The RF exposure design target is typically selected to be less than the RF exposure limit for one or more reasons, such as to account for device uncertainty, to meet the RF exposure limit in exposure scenarios involving simultaneous transmission with other radio components within the same device that have different RF exposure control schemes, to enable the device to have lower RF exposure, and so on.

[0077] Various aspects of the present disclosure provide apparatus and methods for evaluating RF exposure per surface of a wireless device. The total time-averaged RF exposure of multiple radio components can be evaluated for each exposed surface of the wireless device. For time-averaged RF exposure compliance, the wireless device can use an RF exposure manager (e.g., RF exposure manager 122, RF exposure manager 281, etc.) to track historical RF exposures of multiple radio components from each surface of the wireless device. The wireless device can use the RF exposure manager to determine the maximum allowable transmit power for future time intervals based on the RF exposure evaluated per surface. For example, the wireless device can select the minimum value of the transmit power among the values ​​determined for each surface.

[0078] The apparatus and methods described herein for assessing RF exposure per surface may be useful for improving wireless communication performance (e.g., improving signal quality at a receiver, reducing latency, increasing throughput, etc.). For example, the RF exposure assessment per surface may provide an accurate assessment of the RF exposure occurring at a particular surface on a wireless device, thereby allowing the wireless device to assign more exposure margin to certain transmissions.

[0079] Figure 5An isometric view of multiple antennas arranged in various positions of a wireless device 500 (e.g., UE 120) is illustrated. As shown, the wireless device 500 may have six surfaces 502a-502f, including a top surface 502a, a bottom surface 502b, a right surface 502c, a left surface 502d, a front surface 502e, and a rear surface 502f. The wireless device may have multiple antennas, including a first antenna 504a, a second antenna 504b, and a third antenna 504c. The wireless device may also have multiple antenna arrays, including a first antenna array 506a, a second antenna array 506b, and a third antenna array 506c. Each of the antennas and antenna arrays is located at different positions on the wireless device. Each antenna array in the antenna arrays 506a-506c may include one or more antenna arrays 508, which may include one or more antenna array elements 510. In some aspects, antennas 504a-504c can be used for sub-6 GHz communications, and antenna arrays 506a-506c can be used for millimeter wave communications. In some examples, one or more of antenna arrays 506 can be packaged into a module that includes the corresponding array and potentially other components, such as a transceiver chip.

[0080] In various aspects, each of the antenna arrays 506a-506c can enable beamformed signals to be transmitted and / or received by the wireless device 500. For example, the second antenna array 506b can transmit signals via beams 512, wherein each of the beams 512 can represent a particular azimuth and / or elevation angle associated with an angle of departure (AoD).

[0081] In certain aspects, RF exposure scenarios (e.g., head exposure, body-worn exposure, limb exposure, and / or hotspot exposure) may show exposure from certain surfaces of a wireless device in certain positions. A particular exposure scenario may correspond to a device state index (DSI). For example, a head exposure scenario may show exposure from the front surface of a wireless device in various positions, including a left cheek position (e.g., when the wireless device is held against the user's left cheek), a left tilt position (e.g., when the wireless device is held at a tilt position relative to the user's left cheek), a right cheek position, and a right tilt position. A body-worn exposure scenario (e.g., when the wireless device is in a pocket of a user's clothing) may show exposure from the front or back surface of the wireless device. A limb exposure scenario (e.g., when the wireless device is held in the user's hand or in an armband) may show exposure from the front, back, left, right, top, and / or bottom surfaces of the wireless device. Hot spot exposure scenarios (e.g., when the wireless device is not close to human tissue) may present exposure from the front, back, left, right, top, and / or bottom surfaces. SAR and / or PD may be evaluated from all or some surfaces (e.g., front, back, left, right, top, and / or bottom) of the wireless device.

[0082] For time average RF exposure compliance, the wireless device may determine the allowed transmit power for future time intervals based on the total normalized exposure in past time intervals of the time window. In certain aspects, the wireless device may use a normalized exposure ratio for each of its surfaces, such as a normalized SAR and / or PD ratio for each of the front surface, back surface, left surface, right surface, top surface, and / or bottom surface. The normalized exposure ratio may be determined as follows:

[0083] Normalized SAR ratio = [Front SAR, Back SAR, Left SAR, Right SAR, Top SAR, Bottom SAR

[0084] SAR] / (maximum surface SAR)(1)

[0085] Wherein the maximum surface SAR is the maximum SAR value among the values ​​of the surface for a given transmit scenario. Here, the RF exposure (SAR or PD) evaluated on each surface in expression (1) may correspond to the same transmit power for a given antenna or the same transmit power configuration for a given antenna array.

[0086] For example, for a first transmission scenario (e.g., a specific radio access technology, frequency band, antenna, and / or exposure scenario), the wireless device may have the following normalized exposure ratios for the front surface, back surface, left surface, right surface, top surface, and bottom surface, respectively:

[0087] [0.51, 0.41, 1.05, 0.23, 0.4, 0.71] / 1.05=[0.49, 0.39, 1.0, 0.22, 0.38, 0.68].

[0088] For a second transmission scenario (e.g., different radio access technology, frequency band, antenna, and / or exposure scenario), the wireless device may have the following normalized exposure ratios for the corresponding surface:

[0089] [0.42, 0.63, 0.21, 1.09, 0.4, 0.67] / 1.09=[0.36, 0.58, 0.19, 1.0, 0.37, 0.62].

[0090] The wireless device may determine the total normalized exposure per surface for a given time interval (e.g., 0.5s) as follows:

[0091]

[0092] The wireless device may perform a vector calculation on the array of normalized exposure ratios. A product of a normalized transmit power and a normalized exposure ratio may be calculated by applying the normalized transmit power to each of the normalized exposure ratios and generating a normalized exposure value for each of the surfaces. A sum of the normalized exposure values ​​for the transmit scenario may be calculated as a vector sum to generate a total normalized exposure value for each of the surfaces.

[0093] In certain aspects, a wireless device may use a time-averaged maximum transmit power limit per surface (P limit ) to assess time-averaged RF exposure compliance. For example, Plimit per surface can be determined as follows:

[0094] P limit_surface =Plimit / [front SAR ratio, rear SAR ratio, left SAR ratio, right SAR ratio, top SAR ratio, bottom SAR ratio].

[0095] For example, for a first transmission scenario (e.g., a specific radio access technology, frequency band, antenna, and / or exposure scenario), the wireless device may have the following P values ​​for the front surface, the back surface, the left surface, the right surface, the top surface, and the bottom surface, respectively: limit :

[0096] 79.4mW / ([0.49, 0.39, 1.0, 0.22, 0.38, 0.68])=[162, 204, 80, 361, 209, 117].

[0097] For a second transmission scenario (e.g., different radio access technology, frequency band, antenna, and / or exposure scenario), the wireless device may have the following Plimit for the corresponding surface:

[0098] 74.1mW / ([0.36, 0.58, 0.19, 1.0, 0.37, 0.62])=[206, 128, 390, 75, 201, 120].

[0099] The wireless device may determine the total normalized exposure per surface for a given time interval (e.g., 0.5s) as follows:

[0100]

[0101] The wireless device may perform a time averaging operation for each surface and evaluate the allowed transmit power for all active radio components for future time intervals for each surface. The wireless device may select the lowest value of the allowed transmit power among the values ​​for the surface and apply the value at the transceiver, such as the RF transceiver circuit 300.

[0102] In simultaneous transmit scenarios, the time-averaged RF exposure assessment per surface may allow the wireless device to assign more exposure margin, which may translate into greater transmit power and improved wireless performance if the worst surface in terms of exposure is different for the transmit radio. The time-averaged RF exposure assessment per surface may increase computational performance as the number of calculations increases in proportion to the number of surfaces being evaluated.

[0103] In certain aspects, the wireless device may evaluate the time-averaged RF exposure per surface for a subset of exposure scenarios. For example, the wireless device may use the worst-case exposure value for the head exposure scenario and evaluate the time-averaged RF exposure per surface for the hotspot exposure scenario.

[0104] For certain aspects, the wireless device may evaluate the time-averaged RF exposure per surface for a subset of surfaces associated with the wireless device. Using a subset of surfaces to evaluate the time-averaged RF exposure may reduce the number of calculations and improve the computational performance of the RF exposure evaluation. There may be certain aspects in which fewer than all surfaces associated with the wireless device may be evaluated to obtain the time-averaged RF exposure per surface. The number of evaluated surfaces may be reduced to a subset of surfaces. For example, for head exposure, the four positioning associated with the front surface may be reduced to the left positioning and the right positioning of the wireless device, where the left normalized SAR ratio may be equal to the maximum value among the left cheek positioning and the left tilt positioning (e.g., max(left cheek, left tilt)), and the right normalized SAR ratio may be equal to the maximum value among the left cheek positioning and the left tilt positioning (e.g., max(right cheek, right tilt)).

[0105] Surfaces may also be evaluated in subsets in other exposure scenarios. For example, in hotspot mode, instead of using six surfaces (front, back, left, right, top, bottom), the wireless device may evaluate three groups of surfaces, where the first group may include the front and left surfaces, the second group may include the back and bottom surfaces, and the third surface may include the right and top surfaces. The wireless device may evaluate the first group as the maximum value among the front and left surfaces (e.g., set1 = max{front exp.ratio, left exp.ratio}), the second group as the maximum value among the back and bottom surfaces (e.g., set2 = max{back exp.ratio, bottom exp.ratio}), and the third group as the maximum value among the right and top surfaces (e.g., set3 = max{right exp.ratio, top exp.ratio}). Subsets of surfaces may be formed by considering antenna placement between surfaces and corresponding exposure scenarios. For example, if a wireless device has some antennas clustered at a front-left location, a rear-bottom location, and a right-top location, then three subsets as discussed above may be used.

[0106] In the absence of exposure measurements for a particular surface, the normalized exposure ratio may be replaced with a default value, such as 1.0. For surfaces for which exposure information is not available (e.g., not measured due to exclusion criteria), the wireless device may use a default value corresponding to a particular maximum RF exposure limit (e.g., 0.4 W / kg 1 gSAR value). For example, for a body-worn exposure scenario, exposure measurements may be available for the front and back surfaces, but not for the left, right, top, and bottom surfaces due to the exclusion criteria described herein. In this case, the wireless device may use a default value for the normalized exposure for the left, right, top, and bottom surfaces, where the default value may correspond to the maximum RF exposure limit (e.g., 0.4 W / kg per 1 gSAR value).

[0107] In certain aspects, RF exposure information per surface (e.g., normalized exposure ratio and / or P) may be stored per beam (e.g., antenna configuration) and / or per antenna array (e.g., maximum exposure among all beams supported by the antenna array). limit ). The wireless device may assess the time-averaged RF exposure per surface based on the beam and / or antenna array used for a particular transmission.

[0108] Figure 6An example table of normalized SAR ratios for specific surfaces and / or positions is illustrated. In this example, the head exposure scenario may have two normalized SAR ratios for the left position and the right position of the front surface per transmit scenario (e.g., a combination of radio access technology, frequency band, and antenna). The body-worn exposure scenario may have normalized SAR ratios for the front surface, back surface, left surface, right surface, top surface, and bottom surface per transmit scenario (or certain transmit scenarios). It should be understood that the wireless device may have normalized exposure ratios per surface stored for other transmit scenarios (e.g., a combination of radio access technology, frequency band, DSI, surface, and / or antenna / antenna array). For example, for frequency bands below 6 GHz, the wireless device may have normalized SAR ratios per surface stored by antenna / DSI (e.g., the maximum normalized SAR ratio among all radio access technologies / frequency bands supported by the antenna), radio access technology / DSI (e.g., the maximum normalized SAR ratio among all antennas / frequency bands supported in the radio access technology), antenna group / DSI (e.g., the maximum normalized SAR ratio among all radio access technologies / frequency bands / antennas supported in the antenna group), or any combination of radio access technology, frequency band, antenna, antenna array, antenna group, DSI, and surface. That is, in general, storing normalized SAR ratios by radio access technology, frequency band, antenna, DSI and / or surface may include storing normalized SAR ratios by: (i) radio access technology, antenna, DSI and surface; (ii) antenna, DSI and surface; (iii) antenna group, DSI and surface; (iv) radio access technology, antenna group, DSI and surface group; or (v) any combination of radio access technology, frequency band, antenna, antenna array, DSI and surface.

[0109] For certain aspects, time-averaged RF exposure may be evaluated at the antenna array level so that a wireless device may have per-surface exposure information for certain antenna arrays. Fig. 7A An example table of normalized PD ratios for a particular surface for each antenna array (e.g., antenna arrays 506a-506c) is illustrated. In this example, there are normalized PD ratios for the front, back, left, right, top, and bottom surfaces for each of the four antenna arrays. Here, the normalized PD ratio of an antenna array on a given surface can be determined as the maximum ratio of the ratios of all beams supported by the antenna array on that surface (i.e., as Figure 7B Maximum values ​​along each column are illustrated).

[0110] In certain aspects, time-averaged RF exposure may be evaluated at a beam level so that a wireless device may have per-surface exposure information for certain beams. Figure 7BAn example table of normalized PD ratios for a particular surface for each beam (e.g., beam 512) associated with one or more antenna arrays (e.g., antenna arrays 506a-506c) is illustrated. In this example, there are normalized PD ratios for the front, back, left, right, top, and bottom surfaces for each of the three beams. The beams may be transmitted from the same antenna array or different antenna arrays. Here, the RF exposure on a given surface may be evaluated for different transmission and / or RF exposure scenarios as described above. Similar to the normalized SAR ratios, the normalized PD ratios may be stored for each supported beam or antenna array or mmW band or DSI or beam group or antenna array group or mmW band group or SSI group or any other combination.

[0111] Those skilled in the art will understand that Figures 5 to 7B The parameters and values ​​illustrated are exemplary only. Other parameters or parameter categories may be used in addition to or in place of those illustrated. For example, the wireless device may have RF exposure information (e.g., normalized exposure ratio and / or P values) per surface (and / or location) for other exposure scenarios (such as hot spot exposure scenarios and / or limb exposure scenarios). limit ). The wireless device may have exposure information per surface for exposure scenario categories, such as head exposure category (including head exposure scenarios) and non-head exposure category (including body, limb, and hotspot exposure scenarios).

[0112] Despite Figure 6 , Fig. 7A and Figure 7B Tables are illustrated in FIG, but such a structure is not required. The information in these diagrams may be generated, stored, and / or accessed in any number of different ways. In some examples, Figure 6 , Fig. 7A and Figure 7B The data structures corresponding to the tables in are stored in memory 282 and / or memory 338, or one or more memories associated with controller / processor 280 and / or controller 336.

[0113] Figure 8 8 is a flow diagram illustrating example operations 800 for wireless communications in accordance with certain aspects of the present disclosure. Operations 800 may be performed, for example, by a wireless device (e.g., UE 120a in wireless communication network 100). Operations 800 may be implemented as a processor (e.g., Figure 2800 or a subset thereof (e.g., block 802). In addition, the signal transmission and / or reception performed by the wireless device in operation 800 may be performed by one or more antennas (e.g., Figure 2 In some aspects, the transmission and / or reception of signals by the wireless device may be achieved by obtaining and / or outputting signals via a bus interface of one or more processors (eg, controller / processor 280).

[0114] Operations 800 may optionally begin at block 802, where a wireless device may access RF exposure information associated with different surfaces among a plurality of surfaces (eg, surfaces 502a-502f) of the wireless device (eg, Figure 6 , Fig. 7A and Figure 7B ). The wireless device may obtain the RF exposure information via a memory. For example, the RF exposure information may be stored in a memory (e.g., memory 282 and / or memory 338), and the wireless device may access the memory to obtain the RF exposure information.

[0115] The exposure information may include a plurality of exposure parameters associated with different surfaces. For example, each of these parameters may be associated with a different one of the surfaces. These parameters may include a normalized RF exposure ratio or a maximum time-averaged transmit power (e.g., P) associated with different surfaces as described herein. limit ). In some cases, at least one of the plurality of exposure parameters may indicate a normalized RF exposure ratio (e.g., a normalized SAR ratio or a normalized PD ratio) associated with a particular surface among the plurality of surfaces, such as Figure 6 , Fig. 7A and Figure 7B In some cases, at least one of the plurality of exposure parameters may indicate a maximum time-averaged transmit power (e.g., P) associated with a particular surface among the plurality of surfaces. limit ).

[0116] At box 804, the wireless device may transmit a signal based at least in part on the transmit power determined by the RF exposure information and the RF exposure limit. In some cases, the wireless device may transmit simultaneously via multiple antennas (and / or antenna arrays), wherein the simultaneous transmission may include transmissions in the same transmission opportunity or time interval associated with the RF exposure limit. In some cases, the wireless device may transmit simultaneously via multiple radio components. For example, the wireless device may simultaneously transmit via a wireless wide area network (WWAN) radio (e.g., CDMA, E-UTRA, NR, etc.), a wireless local area network (WLAN) radio (e.g., IEEE 802.11), and / or a Bluetooth radio, and / or any combination of satellite, P2P, V2X communications. The wireless device may perform a time-averaged RF exposure assessment per surface as described herein in response to the wireless device transmitting simultaneously via multiple antennas, antenna arrays, and / or radio components.

[0117] In certain aspects, the exposure parameter may use a default value for the exposure information of a particular surface. At least one of the plurality of exposure parameters may have a default value. The default value may be equal to a normalized maximum RF exposure limit (e.g., 1.0). The default value may correspond to a maximum RF exposure limit averaged by tissue mass (e.g., 0.4 W / kg per 1 g).

[0118] For certain aspects, the wireless device may use information associated with certain exposure scenarios (e.g., Figure 6 The exposure information may include multiple groups of one or more exposure parameters associated with different exposure scenarios. As an example, the exposure information may include a first group of one or more exposure parameters and a second group of one or more exposure parameters, wherein the first group of one or more exposure parameters corresponds to a first exposure scenario (e.g., a head exposure scenario), and the second group of one or more exposure parameters corresponds to a second exposure scenario different from the first exposure scenario (e.g., a body exposure scenario). In some aspects, the first group of one or more exposure parameters may include two exposure parameters corresponding to a single surface (e.g., a front surface) of the wireless device in two different positionings (left cheek positioning and right cheek positioning). The second group of one or more exposure parameters includes six exposure parameters corresponding to six surfaces (e.g., surfaces 502a-502f) of the wireless device. The first exposure scenario may correspond to a head exposure scenario. The second exposure scenario may correspond to a body exposure scenario, a limb exposure scenario, a hot spot exposure scenario, or a combination thereof.

[0119] In some aspects, the wireless device may use exposure information associated with a subset of surfaces or all surfaces. In some cases, exposure parameters may be associated with a subset of surfaces. For example, a head exposure scenario may have a normalized exposure ratio associated with a front surface of a wireless device in two different orientations. Exposure parameters may be associated with all surfaces. For example, a body-worn exposure scenario may have a normalized exposure ratio associated with a front surface, a back surface, a left surface, a right surface, a top surface, and a bottom surface.

[0120] In some aspects, a wireless device may have exposure information associated with certain transmission scenarios, such as one or more frequency bands, one or more antennas, and / or one or more antenna arrays, for example, as described herein with respect to Figure 6 , Fig. 7A and Figure 7B described. A transmission scenario may refer to a transmission event having one or more characteristics such as: radio access technology, frequency band, antenna, antenna array, beam, exposure scenario, etc. The exposure information may include multiple sets of one or more exposure parameters associated with different frequency bands, different antennas, different antenna arrays, different beams, or a combination thereof. The exposure information may include a first set of exposure parameters associated with a first frequency band of a radio access technology and a first antenna, and the exposure information may include a second set of exposure parameters associated with a second frequency band of a radio access technology and a first antenna. The first set of exposure parameters and the second set of exposure parameters may have values ​​for each surface of all surfaces or a subset of surfaces of the wireless device.

[0121] For certain aspects, a wireless device may have exposure information associated with one or more beams (e.g., beam 512), for example, as described herein with respect to Figure 7B The exposure information may include multiple sets of one or more exposure parameters (e.g., normalized exposure ratios) associated with different beams among multiple beams associated with one or more antenna arrays of the wireless device. For example, the exposure information may include a first set of exposure parameters associated with a first beam and a second set of exposure parameters associated with a second beam, wherein the first set of exposure parameters and the second set of exposure parameters may have values ​​for each surface of all surfaces or a subset of surfaces of the wireless device.

[0122] For certain aspects, the wireless device may use exposure information associated with the transmit scenario (in a past time interval or a future time interval) to determine the transmit power of the signal. The wireless device may use the exposure information to determine an allowed transmit power for each of two or more of the surfaces of the wireless device based at least in part on the RF exposure limit. The wireless device may determine a total normalized exposure for each of the multiple surfaces in a past time interval associated with a time window of the RF exposure limit, e.g., as described herein with respect to expression (2). The wireless device may determine an allowed transmit power for each of the multiple surfaces in a future time interval associated with the time window based on the total normalized exposure for each surface associated with the past time interval so that the time-averaged RF exposure limit is met, e.g., as described herein with respect to FIG. 4A to FIG. 4C As described. To determine the allowed transmit power, the wireless device may determine the allowed transmit power in the future time interval so that the time average of the allowed transmit power and the past exposure (e.g., the total normalized exposure per surface) within the time window satisfies the time average RF exposure limit. The wireless device may select a minimum value among the allowed transmit powers. The wireless device may transmit a signal at a transmit power less than or equal to the selected value.

[0123] although Figures 1 to 8 The examples depicted in the are described herein with respect to a UE that performs various methods for providing RF exposure compliance to facilitate understanding, but aspects of the present disclosure may also be applied to other wireless devices that perform the RF exposure compliance described herein, such as wireless stations, access points, base stations, and / or customer premises equipment (CPE). In addition, although these examples are described with respect to communications between a UE (or other wireless device) and a network entity, a UE or other wireless device may communicate with a device other than a network entity (e.g., another UE) or with another device in a user's home that is not a network entity.

[0124] It will be appreciated that assessing RF exposure per surface as described herein may enable desired wireless communication performance, such as reduced latency, increased uplink data rates, and / or uplink connectivity at the cell edge, for example, due to an increased exposure margin assignable to transmissions.

[0125] Example Communication Device

[0126] Fig. 9 Examples include operations that may be configured to perform the techniques disclosed herein (such as Figure 8The communication device 900 includes a processing system 902 that may be coupled to a transceiver 908 (e.g., a transmitter and / or a receiver). The transceiver 908 is configured to transmit and receive signals for the communication device 900, such as various signals described herein, via an antenna 910. The processing system 902 may be configured to perform processing functions for the communication device 900, including processing signals received by the communication device 900 and / or to be transmitted by it.

[0127] The processing system 902 includes a processor 904 coupled to a computer readable medium / memory 912 via a bus 906. In some aspects, the computer readable medium / memory 912 is configured to store instructions (e.g., computer executable code) that, when executed by the processor 904, cause the communication device 900 to perform Figure 8 The illustrated operations 800 or other operations for performing the various techniques discussed herein for providing RF exposure compliance. In some aspects, the computer-readable medium / memory 912 stores code 914 for accessing (or obtaining), code 916 for sending (or outputting), code 918 for determining, or any combination thereof.

[0128] In some aspects, the processing system 902 has circuitry 920 configured to implement code stored in the computer-readable medium / memory 912. In some aspects, the circuitry 920 is coupled to the processor 904 and / or the computer-readable medium / memory 912 via a bus 906. For example, the circuitry 920 includes circuitry 922 for accessing (or obtaining), circuitry 924 for sending (or outputting), circuitry 926 for determining, or any combination thereof.

[0129] In some examples, means for sending or transmitting (or means for outputting for sending) may include Figure 2 The transceiver 254 and / or antenna 252 and / or Fig. 9 The transceiver 908 and antenna 910 of the communication device 900 in FIG.

[0130] In some cases, a device may not actually send, for example, signals and / or data, but may have an interface (components for outputting) signals and / or data for transmission. For example, a processor may output signals and / or data to a radio frequency (RF) front end via a bus interface for transmission. Similarly, a device may not actually receive signals and / or data, but may have an interface (components for obtaining) for obtaining signals and / or data received from another device. For example, a processor may obtain (or receive) signals and / or data from an RF front end via a bus interface for reception. 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 Figure 2 as depicted in the example.

[0131] In some examples, means for accessing and / or means for determining may include various processing system components, such as: Fig. 9 or Figure 2 1 , including a receive processor 258, a transmit processor 264, a TX MIMO processor 266, and / or a controller / processor 280.

[0132] Example aspects

[0133] Specific implementation examples are described in the following numbered clauses:

[0134] Aspect 1: A method for wireless communication by a wireless device, the method comprising: accessing radio frequency (RF) exposure information associated with different surfaces among multiple surfaces of the wireless device; and transmitting a signal at a transmission power determined at least in part based on the RF exposure information and an RF exposure limit.

[0135] Aspect 2: The method according to aspect 1, wherein the exposure information includes a plurality of exposure parameters associated with the different surfaces.

[0136] Aspect 3: The method of aspect 2, wherein at least one exposure parameter of the plurality of exposure parameters indicates a normalized RF exposure ratio associated with a particular surface among the plurality of surfaces.

[0137] Aspect 4: The method according to aspect 2 or 3, wherein at least one exposure parameter of the plurality of exposure parameters indicates a maximum time-averaged transmit power associated with a specific surface among the plurality of surfaces.

[0138] Aspect 5: The method according to any one of aspects 2 to 4, wherein at least one exposure parameter of the plurality of exposure parameters has a default value.

[0139] Aspect 6: The method according to aspect 5, wherein the default value is equal to the normalized maximum RF exposure limit.

[0140] Aspect 7: The method according to aspect 5, wherein the default value is equal to the normalized maximum RF exposure design target.

[0141] Aspect 8: The method according to any one of aspects 5 to 7, wherein the default value corresponds to a maximum RF exposure limit averaged over tissue mass.

[0142] Aspect 9: The method according to any one of aspects 5 to 7, wherein the default value corresponds to a maximum RF exposure design target averaged over tissue mass.

[0143] Aspect 10: The method according to any one of aspects 1 to 9, wherein the exposure information comprises multiple sets of one or more exposure parameters associated with different exposure scenarios.

[0144] Aspect 11: A method according to any one of Aspects 1 to 10, wherein the exposure information includes multiple sets of one or more exposure parameters associated with different transmission scenarios, wherein each transmission scenario defines one or more transmission technologies, one or more frequency bands, one or more antennas, or one or more beams, or one or more antenna arrays, DSI, and / or exposure scenarios, or any combination thereof.

[0145] Aspect 12: A method according to any one of Aspects 1 to 11, wherein: the exposure information includes a first group of one or more exposure parameters and a second group of one or more exposure parameters; the first group of one or more exposure parameters corresponds to a first exposure scenario; and the second group of one or more exposure parameters corresponds to a second exposure scenario different from the first exposure scenario.

[0146] Aspect 1 3: A method according to Aspect 1 2, wherein: the first set of one or more exposure parameters includes two exposure parameters corresponding to a single surface of the wireless device in two different positions; and the second set of one or more exposure parameters includes six exposure parameters corresponding to six surfaces of the wireless device.

[0147] Aspect 14: The method according to aspect 13, wherein the first exposure scene corresponds to a head exposure scene.

[0148] Aspect 15: The method according to aspect 13 or 14, wherein the second exposure scenario corresponds to a hot spot exposure scenario or a limb exposure scenario.

[0149] Aspect 16: The method of any one of Aspects 2 to 15, wherein the plurality of exposure parameters are associated with a subset of the surfaces.

[0150] Aspect 17: The method according to any one of aspects 2 to 16, wherein the plurality of exposure parameters are associated with all of the surfaces.

[0151] Aspect 18: The method according to any one of aspects 1 to 17, wherein the exposure information comprises multiple sets of one or more exposure parameters associated with different beams among the plurality of beams.

[0152] Aspect 19: The method according to any one of aspects 1 to 18, wherein the exposure information includes multiple sets of one or more exposure parameters associated with different frequency bands, different antennas, or a combination thereof.

[0153] Aspect 20: The method according to any one of aspects 1 to 19, wherein the exposure information includes multiple sets of one or more exposure parameters associated with different frequency bands, different antenna arrays, or a combination thereof.

[0154] Aspect 21: A method according to any one of Aspects 1 to 20, wherein the RF exposure information includes multiple sets of one or more exposure parameters associated with different frequency bands, different antennas, different antenna arrays, different radio access technologies, different surfaces of the wireless device, different positioning of the wireless device, or a combination thereof.

[0155] Aspect 22: According to a method described in any one of Aspects 1 to 21, the method further includes: determining an allowed transmit power for each of two or more of the surfaces of the wireless device based at least in part on the RF exposure limit using the exposure information; selecting a minimum value from the allowed transmit powers; and transmitting the signal at the transmit power less than or equal to the selected value.

[0156] Aspect 23: The method according to Aspect 22, wherein determining the allowed transmit power comprises determining the allowed transmit power in a future time interval so that the allowed transmit power within a time window and a time average of past exposures satisfy the RF exposure limit.

[0157] Aspect 24: An apparatus for wireless communication, the apparatus comprising: one or more memories that collectively store computer-executable instructions; and one or more processors that are coupled to the one or more memories, the one or more processors being collectively configured to execute the computer-executable instructions so that the apparatus performs operations including: accessing radio frequency (RF) exposure information associated with different surfaces among multiple surfaces of the wireless device, and sending a signal at a transmit power determined at least in part based on the RF exposure information and an RF exposure limit.

[0158] Aspect 25: An apparatus for wireless communication, the apparatus comprising: a component for accessing radio frequency (RF) exposure information associated with different surfaces among multiple surfaces of a wireless device; and a component for transmitting a signal at a transmit power determined at least in part based on the RF exposure information and an RF exposure limit.

[0159] Aspect 26: A computer-readable medium having instructions stored thereon for: accessing radio frequency (RF) exposure information associated with different surfaces among multiple surfaces of a wireless device; and transmitting a signal at a transmit power determined at least in part based on the RF exposure information and an RF exposure limit.

[0160] Aspect 27: A device comprising: one or more memories, the one or more memories collectively storing computer-executable instructions; and one or more processors, the one or more processors coupled to the one or more memories and collectively configured to execute the computer-executable instructions so that the device performs a method according to any one of Aspects 1 to 23.

[0161] Aspect 28: An apparatus comprising means for performing the method according to any one of aspects 1 to 23.

[0162] Aspect 29: A non-transitory computer-readable medium comprising computer-executable instructions, which, 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 23.

[0163] Aspect 30: A computer program product embodied on a computer-readable storage medium, the computer program product comprising code for executing the method according to any one of aspects 1 to 23.

[0164] The techniques described herein may be used for various wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), Advanced LTE (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 IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks may implement radio technologies 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, and the like. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). NR is an emerging wireless communication technology under development.

[0165] In 3GPP, the term "cell" may refer to the coverage area of ​​a Node B (NB) and / or a NB subsystem serving the coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and BS, next generation NodeB (gNB or gNodeB), access point (AP), distributed unit (DU), carrier, or transmit receive point (TRP) may be used interchangeably. A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or other types of cells. A macro cell 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 pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs associated with a femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS.

[0166] UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a customer premises equipment (CPE), a cellular phone, a smart phone, 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 medical 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 transportation component or sensor, a smart meter / sensor, an industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium. Some UEs may be considered as 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 can communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node can provide, for example, a connection to or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0167] In some examples, access to the air interface can be scheduled. A scheduling entity (e.g., BS) allocates resources for communications between some or all devices and equipment within its service area or cell. A scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, subordinate entities use resources allocated by the scheduling entity. The base station is not the only entity that can act as a scheduling entity. In some examples, a UE may be used as a scheduling entity and may 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 communications. In some examples, a UE may be used as a scheduling entity in a peer-to-peer (P2P) network or in a mesh network. In a mesh network example, in addition to communicating with a scheduling entity, UEs may also communicate directly with each other.

[0168] The method disclosed herein includes one or more steps or actions for implementing the method. The steps and / or actions of the method can be interchangeable with each other without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions can be modified without departing from the scope of the claims.

[0169] 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 multiple processors configured to collectively perform one or more operations. In the case of multiple processors, the execution of one or more operations may be divided among different processors, but a 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 multiple memories configured to collectively store data and / or instructions.

[0170] 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). For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0171] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, generating, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, and the like. Furthermore, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Furthermore, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0172] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the various aspects shown herein, but should be given the full scope consistent with the language of the claims, wherein unless otherwise specified, reference to an element in the singular form is not intended to mean "one and only one", but "one or more". Unless otherwise specified, the term "some" refers to one or more. All structural and functional equivalents that are known or will be known to a person of ordinary skill in the art throughout the various aspects of the elements described in this disclosure are expressly incorporated herein by reference, and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly recorded in the claims. Any claim element should not be interpreted according to the provisions of 35 USC § 112 (f), unless the phrase "parts for ..." is used to expressly record the element, or in the case of a method claim, the phrase "step for ..." is used to record the element.

[0173] The various operations of the above methods may be performed by any suitable components capable of performing the corresponding functions. These components may include various hardware and / or software components and / or arrays, including but not limited to circuits, application specific integrated circuits (ASICs) or processors. Generally, where there are operations illustrated in the accompanying drawings, those operations may have corresponding corresponding components plus functional components with similar numbers.

[0174] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed with 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 components, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0175] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. Depending on the specific application of the processing system and the overall design constraints, the bus may include any number of interconnecting buses and bridges. 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, etc., to the processing system via the bus. The network adapter may be used to implement signal processing functions at the physical (PHY) layer. In the UE (see Figure 1 ), a user interface (e.g., a 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, and the like, 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 processors and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits that can execute software. Those skilled in the art will recognize how best to implement the described functionality of the processing system depending on the specific application and the overall design constraints imposed on the entire system.

[0176] If implemented in software, each function may be stored on or sent through a computer-readable medium as one or more instructions or codes. Software should be broadly interpreted as meaning instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or other. Computer-readable media include both computer storage media and communication media, including any media that facilitates the transfer of computer programs from one place to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. A computer-readable storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. In an alternative, the storage medium may be integral with the processor. For example, a machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon that is separated from a wireless node, all of which may be accessed by a processor through a bus interface. Alternatively or in addition, a machine-readable medium or any part thereof may be integrated into a processor, such as in the case of having a cache and / or a general register stack. By way of example, examples of machine-readable storage media may include 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 media, or any combination thereof. Machine-readable media may be implemented in a computer program product.

[0177] A software module may include a single instruction, perhaps multiple instructions, and may be distributed over several different code segments, between different programs, and across multiple storage media. A computer-readable medium may include multiple 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 sending module and a receiving module. Each software module may reside in a single storage device or may be distributed across multiple storage devices. By way of example, when a triggering event occurs, a software module may be loaded from a hard drive into a RAM. During the 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 register stack for execution by the processor. When the functionality of a software module is mentioned below, it will be understood that such functionality is implemented by a processor when executing instructions from the software module.

[0178] Moreover, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared (IR), radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology such as infrared, radio, and microwave are included in 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 Optical disks, where magnetic disks typically reproduce data magnetically, and optical disks use lasers to reproduce data optically. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0179] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include a computer-readable medium having instructions stored (and / or encoded) thereon, such instructions (e.g., for performing the operations described herein and Figure 8 The instructions (exemplifying the operations) can be executed by one or more processors to perform the operations described herein.

[0180] In addition, it should be understood that the modules and / or other appropriate components for performing the methods and techniques described herein can be downloaded and / or otherwise obtained by the user terminal and / or base station where applicable. For example, such a device can be coupled to a server to facilitate the transfer of components for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage component (e.g., RAM, ROM, or a physical storage medium such as a compact disc (CD) or a floppy disk) so that the user terminal and / or base station can obtain the various methods when the storage component is coupled to or provided to the device. In addition, any other appropriate technology for providing the methods and techniques described herein to the device can be used.

[0181] 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. A method for wireless communication by a wireless device, the method comprising: accessing radio frequency (RF) exposure information associated with a different surface among a plurality of surfaces of the wireless device; as well as A signal is transmitted at a transmit power determined based at least in part on the RF exposure information and the RF exposure limit. 2 . The method of claim 1 , wherein the RF exposure information comprises a plurality of exposure parameters associated with the different surfaces. 3 . The method of claim 2 , wherein at least one exposure parameter of the plurality of exposure parameters indicates a normalized RF exposure ratio associated with a particular surface among the plurality of surfaces. 4 . The method of claim 2 , wherein at least one exposure parameter of the plurality of exposure parameters indicates a maximum time-averaged transmit power associated with a particular surface among the plurality of surfaces. The method of claim 2 , wherein at least one exposure parameter of the plurality of exposure parameters has a default value. The method of claim 5 , wherein the default value is equal to a normalized maximum RF exposure design target. 7 . The method of claim 1 , wherein the RF exposure information comprises multiple sets of one or more exposure parameters associated with different exposure scenarios.

8. The method according to claim 1, wherein: The RF exposure information includes a first set of one or more exposure parameters and a second set of one or more exposure parameters; The first set of one or more exposure parameters corresponds to a first exposure scenario; and The second set of one or more exposure parameters corresponds to a second exposure scenario different from the first exposure scenario.

9. The method according to claim 8, wherein: The first set of one or more exposure parameters includes two exposure parameters corresponding to a single surface of the wireless device in two different orientations; and The second set of one or more exposure parameters includes six exposure parameters corresponding to six surfaces of the wireless device.

10. The method of claim 9, wherein the first exposure scenario corresponds to a head exposure scenario. The method of claim 9 , wherein the second exposure scenario corresponds to a hot spot exposure scenario or a limb exposure scenario.

12. The method of claim 2, wherein the plurality of exposure parameters are associated with a subset of the different surfaces.

13. The method of claim 2, wherein the plurality of exposure parameters are associated with all of the different surfaces.

14. The method of claim 1, wherein the RF exposure information comprises multiple sets of one or more exposure parameters associated with different beams among a plurality of beams.

15. The method of claim 1, wherein the RF exposure information comprises multiple sets of one or more exposure parameters associated with different frequency bands, different antennas, or a combination thereof.

16. The method of claim 1, wherein the RF exposure information comprises multiple sets of one or more exposure parameters associated with different frequency bands, different antenna arrays, or a combination thereof.

17. The method of claim 1, wherein the RF exposure information comprises multiple sets of one or more exposure parameters associated with different frequency bands, different antennas, different antenna arrays, different radio access technologies, different surfaces of the wireless device, different positioning of the wireless device, or a combination thereof.

18. The method according to claim 1, further comprising: determining an allowed transmit power for each of two or more of the different surfaces of the wireless device using the RF exposure information based at least in part on the RF exposure limit; Selecting a minimum value from among the allowed transmit powers; as well as The signal is transmitted at the transmit power that is less than or equal to the selected value.

19. The method of claim 18, wherein determining the allowed transmit power comprises determining the allowed transmit power in a future time interval such that a time average of the allowed transmit power within a time window and past exposures satisfies the RF exposure limit.

20. An apparatus for wireless communication, the apparatus comprising: one or more memories that collectively store computer-executable instructions; and One or more processors, the one or more processors coupled to the one or more memories, the one or more processors being collectively configured to execute the computer-executable instructions to cause the apparatus to perform operations including: accessing radio frequency (RF) exposure information associated with different surfaces among a plurality of surfaces of the device, and A signal is transmitted at a transmit power determined based at least in part on the RF exposure information and the RF exposure limit.

21. The apparatus of claim 20, wherein the RF exposure information comprises a plurality of exposure parameters associated with the different surfaces.

22. The apparatus of claim 21, wherein at least one exposure parameter of the plurality of exposure parameters indicates a normalized RF exposure ratio associated with a particular surface among the plurality of surfaces.

23. The apparatus of claim 21, wherein at least one exposure parameter of the plurality of exposure parameters indicates a maximum time-averaged transmit power associated with a particular surface among the plurality of surfaces.

24. The apparatus of claim 21, wherein at least one exposure parameter of the plurality of exposure parameters has a default value.

25. The apparatus of claim 24, wherein the default value is equal to a normalized maximum RF exposure design target.

26. The apparatus of claim 20, wherein the RF exposure information comprises multiple sets of one or more exposure parameters associated with different exposure scenarios.

27. The apparatus of claim 20, wherein: The RF exposure information includes a first set of one or more exposure parameters and a second set of one or more exposure parameters; The first set of one or more exposure parameters corresponds to a first exposure scenario; and The second set of one or more exposure parameters corresponds to a second exposure scenario different from the first exposure scenario.

28. The apparatus of claim 27, wherein: The first set of one or more exposure parameters includes two exposure parameters corresponding to a single surface of the device in two different orientations; and The second set of one or more exposure parameters includes six exposure parameters corresponding to six surfaces of the device.

29. An apparatus for wireless communication, the apparatus comprising: means for accessing radio frequency (RF) exposure information associated with different surfaces among a plurality of surfaces of the device; and Means for transmitting a signal at a transmit power determined based at least in part on the RF exposure information and the RF exposure limit.

30. A non-transitory computer readable medium having stored thereon instructions for: accessing radio frequency (RF) exposure information associated with different surfaces among a plurality of surfaces of the wireless device; and A signal is transmitted at a transmit power determined based at least in part on the RF exposure information and the RF exposure limit.

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