Antenna aware energy reservation for radio frequency exposure compliance

Abstract

Certain aspects of the present disclosure provide techniques and apparatus for antenna aware energy reservation for radio frequency (RF) exposure compliance. An example method of wireless communication includes obtaining information associated with a plurality of antenna ports. The method also includes determining one or more reserves based at least in part on the information. The method also includes transmitting a first signal via the first antenna port at a first transmit power determined based at least in part on the one or more reserves while maintaining at least a portion of the one or more reserves for future transmission via the second antenna port.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims the benefit of and priority to U.S. Patent Application No. 18 / 189,838, filed March 24, 2023, which is incorporated by reference herein in its entirety. TECHNICAL FIELD

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

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. Modern wireless communication devices, such as cellular telephones, 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 can undergo extensive certification processes before being shipped to market. To ensure that wireless communication devices comply with the RF exposure limits, techniques have been developed to enable wireless communication devices to assess RF exposure from the wireless communication devices and adjust transmit power of the wireless communication devices accordingly to comply with the RF exposure limits. SUMMARY

[0005] Some aspects provide a method of wireless communication by a wireless device. The method includes obtaining information associated with a plurality of antenna ports. The method further includes determining one or more reservations based at least in part on the information. The method further includes transmitting a first signal via a first antenna port with a first transmit power determined based at least in part on the one or more reservations while maintaining at least a portion of the one or more reservations for future transmissions via a second antenna port.

[0006] Some aspects provide an apparatus for wireless communication. The apparatus includes a memory and a processor coupled with the memory. The processor is configured to obtain information associated with a plurality of antenna ports, determine one or more reservations based at least in part on the information, and control transmission of a first signal via a first antenna port with a first transmit power determined based at least in part on the one or more reservations while maintaining at least a portion of the one or more reservations for future transmissions via a second antenna port.

[0007] Some aspects provide an apparatus for wireless communication. The apparatus includes means for obtaining information associated with a plurality of antenna ports. The apparatus further includes means for determining one or more reservations based at least in part on the information. The apparatus further includes means for transmitting a first signal via a first antenna port with a first transmit power determined based at least in part on the one or more reservations while maintaining at least a portion of the one or more reservations for future transmissions via a second antenna port.

[0008] Some aspects provide a computer-readable medium. The computer-readable medium includes instructions stored thereon to: obtain information associated with a plurality of antenna ports; determine one or more reservations based at least in part on the information; and transmit a first signal via a first antenna port at a first transmit power determined based at least in part on the one or more reservations while maintaining at least a portion of the one or more reservations for future transmissions via a second antenna port.

[0009] Other aspects provide an apparatus that is operable, configured, or otherwise adapted to perform the methods previously described and those described elsewhere herein; a non-transitory computer readable medium comprising instructions to cause a processor of an apparatus to perform the methods previously described and those described elsewhere herein; a computer program product embodied on a computer readable storage medium comprising code to perform the methods previously described and those described elsewhere herein; and / or a apparatus comprising means to perform the methods previously described and those described elsewhere herein. For example, the apparatus can comprise a processing system, a device having a processing system, or a processing system in cooperation with one or more networks.

[0010] To the accomplishment of the foregoing and related aspects, one or more aspects comprise the features as fully described herein below and particularly pointed out in the claims. The following description and the appended drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects can be employed. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order that the foregoing and other aspects can be understood in detail, a brief description of the aspects can be found immediately below, which aspects are described in greater detail in the detailed description section below. It is to be noted that the appended drawings illustrate only certain typical aspects in accordance with the disclosure and therefore are not to be considered limiting of its scope, for the disclosure can admit to other equally effective aspects.

[0012] Figure 1 FIG. 1 is a block diagram conceptually illustrating an example wireless communication system that demonstrates radio frequency (RF) exposure to a person.

[0013] Figure 2 FIG. 2 is a block diagram conceptually illustrating a design of an example wireless communication device that communicates with another device.

[0014] Figure 3 FIG. 3 is a graph that shows an example of transmit power variation over time that complies with RF exposure limits.

[0015] Figure 4 FIG. 1 is a diagram illustrating an example history buffer for antenna-aware energy reservation.

[0016] Figure 5 FIG. 2 is a timing diagram illustrating an example energy reservation applied when switching from one antenna port to another.

[0017] Figure 6 FIG. 3 is a flow diagram illustrating example operations for wireless communication by a wireless device.

[0018] Figure 7 A communication device is shown that can include various components configured to perform operations for the techniques disclosed herein.

[0019] To facilitate understanding, identical reference numbers have been used, where possible, to designate identical elements that are common between the figures. It is intended that elements disclosed in one aspect can be utilized in other aspects as appropriate, without specific recitation. DETAILED DESCRIPTION

[0020] Aspects of the disclosure provide apparatus, methods, processing systems, and computer readable media for complying with radio frequency (RF) exposure limits using antenna-aware energy reservation.

[0021] In some cases, a wireless communication device can communicate by switching between multiple antenna ports, which can have varying RF exposure limits and / or maximum allowed transmit power. For example, a wireless device can communicate via a first antenna port in a first transmission occasion, and in a second transmission occasion, the wireless device can communicate via a second antenna port. The first antenna port can have a particular RF exposure limit, and the second antenna port can have a lower RF exposure limit relative to the limit associated with the first antenna port. As used herein, an antenna port can refer to one or more (logical or physical) output ports and / or transmission paths (e.g., transmit / transmit chains) configured to transmit RF signals via any one of one or more frequency bands for wireless communication, one or more transceivers, and / or one or more radio access technologies (RATs) (e.g., wireless wide area network (WW AN), wireless local area network (WLAN), short-range communication (e.g., Bluetooth), non-terrestrial communication, vehicle-to-everything (V2X) communication, etc.). For example, for uplink carrier aggregation (or multi-connectivity) in WW AN communication, each active component carrier for wireless communication can be treated as a separate antenna port. Similarly, multi-band transmission of IEEE 802.11 can be treated as a separate antenna port for each frequency band (e.g., 2.4 GHz, 5 GHz, or 6 GHz). For beamforming, one or more antenna elements, one or more antenna arrays, and / or one or more antenna modules used to transmit a particular beam can be treated as a separate antenna port, such that each of multiple antenna ports can correspond to one or more different beams.

[0022] A wireless device can transmit signals at a transmit power that complies with RF exposure limits. The wireless device can evaluate the transmit power over a rolling (e.g., moving or running) time window in order to comply with time-averaged RF exposure limits. In some cases, the wireless device can reserve energy in the time window for certain communications (e.g., priority communications and / or services). When determining the amount of energy to reserve for such communications, the wireless device can take into account properties associated with an active antenna port (e.g., a first antenna port). When switching to a different antenna port, the energy reserved by the device for the previous antenna port (e.g., the first antenna port) can not be sufficient to meet the energy specifications of the new antenna port (e.g., a second antenna port), for example, due to different RF exposure limits associated with the new antenna port. In such cases, the wireless device can not allocate sufficient energy to transmit certain lower-priority communications or to maintain a target power level or to maintain high-priority communications. As a result, communications that rely on the reserved energy can degrade in performance (e.g., reduced transmit power can result in reduced throughput, increased latency, and / or reduced range) and / or temporarily pause transmissions to comply with RF exposure limits.

[0023] Aspects of the disclosure provide apparatuses and methods for antenna-aware energy reservation. When determining energy reservations for certain communications (e.g., high-priority communications and / or high-power buffers), a wireless device can consider transmit power properties associated with multiple antenna ports. As an example, a wireless device can maintain a history buffer of information associated with multiple antenna ports, such as all antenna ports available to the wireless device or a subset of such antenna ports, as further described herein. The history buffer can include any of various information for each antenna port, such as a maximum transmit power (e.g., P CMAX ), a maximum time-averaged transmit power (e.g., P limit ), a target power, etc. The wireless device can determine a reservation energy for certain communications based on the history buffer. For example, the wireless device can set the reservation energy to an amount that would take effect on an antenna port with the most stringent transmit power properties (e.g., the lowest maximum transmit power and / or the lowest maximum time-averaged transmit power). In such a case, the wireless device can switch to the antenna port that requires the highest in terms of transmit power characteristics, and maintain an expected performance level for certain communications (e.g., communications that rely on the reservation energy).

[0024] The apparatuses and methods for antenna-aware energy reservation described herein can provide any of various advantages. The apparatuses and methods described herein can allow a wireless device to reserve sufficient energy for certain communications regardless of an antenna port used for the communications, allowing the wireless device to switch between antenna ports without impacting performance of certain communications associated with the reservation energy. In such a case, due to the antenna-aware reservation described herein, the wireless device can experience increased throughput, reduced latency, and / or increased communication range.

[0025] Example RF exposure compliance

[0026] Figure 1 An example wireless communication system 100 in which aspects of the disclosure can be performed is shown. For example, the wireless communication system 100 can include a wireless wide area network (WW AN) and / or a wireless local area network (WLAN). For example, the WW AN can include a New Radio 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), a Code Division Multiple Access (CDMA) system (e.g., a 2G / 3G network), any future WW AN system, or any combination thereof. The WLAN can include a wireless network configured for communication according to an IEEE standard, such as one or more of the 802.11 standards, etc.

[0027] In some cases, the wireless communication system 100 may include a device-to-device (D2D) communication network or a short-range communication system, such as Bluetooth communication.

[0028] like Figure 1 As shown, the wireless communication system 100 may include a first wireless device 102 that communicates with any of a variety of second wireless devices 104a-f (second wireless devices 104) via any of a variety of radio access technologies (RATs), wherein a wireless device may refer to a wireless communication device. RATs may include, for example, WWAN communication (e.g., E-UTRA and / or 5G NR), WLAN communication (e.g., IEEE 802.11), vehicle-to-everything (V2X) communication, non-terrestrial network (NTN) communication, short-range communication (e.g., Bluetooth), etc.

[0029] The first wireless device 102 may transmit RF signals in the vicinity of a person 108, who may be a user and / or bystander of the first wireless device 102. As an example, the first wireless device 102 may be held in the hand of the person 108 and / or positioned against or near the head of the person 108. In some cases, the first wireless device 102 may be located in the pocket or bag of the person 108. In some cases, the first wireless device 102 may be positioned near the person 108 as a mobile hotspot. To ensure that the person 108 is not excessively exposed to RF emissions from the first wireless device 102, the first wireless device 102 may control the transmission power associated with the RF signal according to RF exposure limits, as further described herein, wherein the RF exposure limits may depend on the corresponding exposure scenario (e.g., head exposure, hand (limb) exposure, body (body-worn) exposure, hotspot exposure, etc.).

[0030] The first wireless device 102 may include any wireless communication device from a variety of wireless communication devices, including user equipment (UE), wireless station, access point, customer premises equipment (CPE), etc. In some aspects, according to various aspects of this disclosure, the first wireless device 102 includes an RF exposure manager 106 that performs antenna-sensing power reservation.

[0031] The second wireless devices 104a-f may include, for example, base station 104a, aircraft 104b, satellite 104c, vehicle 104d, access point 104e, and / or UE 104f. Furthermore, the wireless communication system 100 may include a terrestrial aspect, such as terrestrial network entities (e.g., base station 104a and / or access point 104e), and / or a non-terrestrial aspect, such as aircraft 104b and satellite 104c, which may include airborne network entities (e.g., one or more base stations) capable of communicating with other network elements (e.g., terrestrial base stations) and / or user equipment.

[0032] Base station 104a typically includes: NodeB, enhanced NodeB (eNB), next-generation enhanced NodeB (ng-eNB), next-generation NodeB (gNB or gNodeB), access point, basic transceiver station, radio base station, radio transceiver, transceiver function, transmit / receive point, etc. Base station 104a can provide communication coverage for a corresponding geographic coverage area, which may sometimes be referred to as a cell, and in some cases may overlap (e.g., a small cell may have a coverage area that overlaps with the coverage area of ​​a macro cell). For example, the base station can provide communication coverage for macro cells (covering a relatively large geographic area), pico cells (covering a relatively small geographic area, such as a stadium), femtocells (covering a relatively small geographic area (e.g., a home)), and / or other types of cells.

[0033] The first wireless device 102 and / or UE 104f may more generally include: cellular phones, smartphones, Session Initiation Protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players, cameras, game consoles, tablets, smart devices, wearable devices, vehicles, electricity meters, air pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, Internet of Things (IoT) devices, always-on (AON) devices, edge processing devices, or other similar devices. The UE may also be more generally referred to as a mobile device, wireless device, wireless communication device, station, mobile station, user station, mobile user station, mobile unit, user unit, wireless unit, remote unit, remote device, access terminal, mobile terminal, wireless terminal, remote terminal, handheld device, etc.

[0034] In some cases, the first wireless device 102 may comply with RF exposure limits to control the transmit power used to transmit RF signals. RF exposure can be expressed as a specific absorption rate (SAR), which measures the energy absorption per unit mass of human tissue and can be measured in units of watts per kilogram (W / kg). RF exposure can also be expressed as power density (PD), which measures the energy absorption per unit area and can be measured in units of mW / cm². In some cases, a maximum permissible exposure (MPE) limit regarding PD can be imposed on wireless communication devices using transmission frequencies above 6 GHz. The frequency band from 24 GHz to 71 GHz is sometimes referred to as “millimeter wave” (“mmW” or “mmWave”). MPE limits are a measure of regulation for area-based exposure, such as a number (X) watts (W / m²) per square meter, averaged over a defined area and time-averaged over a frequency-dependent time window. 2) to prevent human exposure hazards represented by tissue temperature changes. Certain RF exposure limits can be specified based on a maximum RF exposure metric (e.g., SAR or PD) averaged over a specified time window (e.g., 100 or 360 seconds for sub-6 GHz bands or 2 seconds for 60 GHz bands).

[0035] SAR can be used to evaluate RF exposure for transmission frequencies less than 6 GHz, which covers wireless communication technologies such as 2G / 3G (e.g., CDMA), 4G (e.g., E-UTRA), 5G (e.g., New Radio (NR) in sub-6 GHz bands), IEEE 802.11 (e.g., a / b / g / n / ac), etc. PD can be used to evaluate RF exposure for transmission frequencies higher than 6 GHz, which covers wireless communication technologies such as IEEE 802.11 ad, 802.11 ay, 5G millimeter wave bands, etc. Thus, different metrics can be used to evaluate RF exposure for different wireless communication technologies.

[0036] A wireless device (e.g., the first wireless device 102) can be capable of transmitting signals using multiple wireless communication technologies and / or frequency bands, and in some cases, can be capable of transmitting such signals simultaneously. For example, a wireless device can transmit signals using a first wireless communication technology operating at 6 GHz or below (e.g., 3G, 4G, 5G, 802.11a / b / g / n / ac, etc.) and a second wireless communication technology operating above 6 GHz (e.g., millimeter wave 5G in the 24-60 GHz band, IEEE 802.11 ad, or 802.11 ay). In certain aspects, a wireless device can transmit signals using a first wireless communication technology (e.g., 3G, 4G, 5G, IEEE 802.11 ac in sub-6 GHz bands, etc.) in which RF exposure can be measured according to SAR and a second wireless communication technology (e.g., 5G in the 24-71 GHz band, IEEE 802.11 ad, 802.11 ay, etc.) in which RF exposure can be measured according to PD.

[0037] Figure 2Example components of the first wireless device 102 are shown, which can be used to communicate with any of the second wireless devices 104a-f in the proximity of the human tissue represented by the person 108 in some cases. At the first wireless device 102, a processor 210 can obtain data and / or control information. In certain aspects, the processor 210 can process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. If applicable, the processor 210 can perform spatial processing on the data symbols, control symbols, and / or reference symbols and can provide output symbol streams to a modulator 212. In some cases, aspects of the processor 210 can be integrated (incorporated and / or shared) with the modulator 212, such as an RF exposure manager 106, microcontroller, microprocessor, baseband processor, medium access control (MAC) processor, digital signal processor, etc.

[0038] The modulator 212 can be coupled to a transmit (TX) path 214 (also referred to as a transmit chain) for transmitting signals via one or more antennas 218 and a receive (RX) path 216 (also referred to as a receive chain) for receiving signals via the antennas 218. When the TX path 214 and the RX path 216 share an antenna 218, the paths can interface with the antenna via an interface 220, which can include any of a variety of suitable RF devices, such as switches, duplexers, antenna shares, multiplexers, etc. As an example, the modulator 212 can output digital in-phase (I) and / or quadrature (Q) baseband signals representing respective symbols to a digital-to-analog converter (DAC) 222.

[0039] From the DAC 222, which receives the I or Q baseband analog signals, the TX path 214 can include a baseband filter (BBF) 224, a mixer 226 (which can include one or more mixers), and a power amplifier (PA) 228. The BBF 224 filters the baseband signals received from the DAC 222, and the mixer 226 mixes the filtered baseband signals with a transmit local oscillator (LO) signal to convert the baseband signals to different frequencies (e.g., upconvert from baseband to radio frequency). In some aspects, the frequency conversion process produces sum and difference frequencies between the LO frequency and the frequency of the baseband signals. The sum and difference frequencies are referred to as the beat frequencies. Some of the beat frequencies are in the RF range, such that the signals output by the mixer 314 are typically RF signals, which can be amplified by the PA 228 before transmission by the antenna 218. The antenna 218 can transmit the RF signals, which can be received at the second wireless device 104. While one mixer 226 is shown, several mixers can be used to upconvert the filtered baseband signals to one or more intermediate frequencies, and thereafter upconvert the intermediate frequency signals to the frequencies used for transmission.

[0040] The RX path 216 can include a low noise amplifier (LNA) 230, a mixer 232 (which can include one or several mixers), and a baseband filter (BBF) 234. RF signals received via the antenna 218 (e.g., from the second wireless device 104) can be amplified by the LNA 230, and the mixer 232 mixes the amplified RF signals with a receive local oscillator (LO) signal to convert the RF signals to baseband frequencies (e.g., downconvert). The baseband signals output by the mixer 232 can be filtered by the BBF 234 before being converted to digital I or Q signals by an analog-to-digital converter (ADC) 236 for digital signal processing. The modem 212 can receive the digital I or Q signals and further process the digital signals, e.g., demodulate the digital signals.

[0041] Certain transceivers can employ a frequency synthesizer with a voltage controlled oscillator (VCO) to generate a stable tunable LO frequency with a particular tuning range. Thus, a transmit LO frequency can be generated by a frequency synthesizer 238, which can be buffered or amplified by an amplifier (not shown) before being mixed with a baseband signal in the mixer 226. Similarly, a receive LO frequency can be generated by the frequency synthesizer 238, which can be buffered or amplified by an amplifier (not shown) before being mixed with an RF signal in the mixer 232. Separate frequency synthesizers can be used for the TX path 214 and the RX path 216.

[0042] The processor 210 and / or modem 212 can control transmission of signals via the TX path 214 and / or reception of signals via the RX path 216. In some aspects, the processor 210 and / or modem 212 can be configured to perform various operations, such as those associated with the methods described herein. The processor 210 and / or modem 212 can include a microcontroller, microprocessor, application processor, baseband processor, MAC processor, neural network processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof. The memory 240 can store data and program codes (e.g., computer-readable instructions) for performing wireless communication as described herein. The memory 240 can be external (as shown) and / or incorporated with the processor 210 and / or modem 212. In certain instances, the RF exposure manager 106 (as implemented via the processor 210 and / or modem 212) can determine a transmit power (e.g., corresponding to certain gain levels applied to the TX path 214 including the BBF 224, the mixer 226, and / or the PA 228) that complies with RF exposure limits set by national-specific regulations and / or international guidelines (e.g., International Commission on Non-Ionizing Radiation Protection (ICNRP) guidelines), as described herein.

[0043] The first wireless device 102 can be capable of communicating via multiple antenna ports (e.g., antenna ports 244a, 244b), for example, as multi-band communications, beamformed (or spatially diverse) communications, and / or multi-radio access technology (RAT) communications. For example, in a multi-band context, the antennas can be capable of communicating across any of a variety of frequency bands. In some cases, the antennas can be tuned to a particular frequency range or one or more frequency bands. In beamforming, an antenna array (e.g., an array of antenna elements) can emit a radiation pattern in a particular direction and / or with a particular beam shape, where different antennas can be used to emit different beams. In some cases, the first wireless device 102 can be capable of communicating via multiple RATs, such as wireless wide area network (WW AN) RATs (e.g., 5G New Radio, Evolved Universal Terrestrial Radio Access (E-UTRA), Universal Mobile Telecommunications System (UMTS), and / or Code Division Multiple Access (CDMA)), wireless local area network (WLAN) RATs (e.g., IEEE 802.11), short-range communications (e.g., Bluetooth), non-terrestrial communications, device-to-device (D2D) communications, Internet of Things (IoT) communications, ANT+ communications, near-field communications (NFC), ultra-wideband (UWB) communications, vehicle-to-everything (V2X) communications, and / or other communications (e.g., future RATs). The RATs can use different antennas, antenna elements, and / or antenna modules for wireless communications.

[0044] As an example of multi-antenna communications, the first wireless device 102 can communicate with the second wireless device 104 using beamforming. The first wireless device 102 can include multiple antennas (e.g., antenna 218a-218b), such as antenna elements, antenna panels, and / or antenna arrays to facilitate beamforming. In some cases, the first wireless device 102 can transmit and / or receive beamformed signals via one or more beams 242, each of which can correspond to a different transmit and / or receive direction and / or a different beam shape (e.g., narrow or wide beam shape). For example, the first wireless device 102 can switch from communicating via a first beam 242a using a first antenna port 244a associated with a first antenna 218a to communicating via a second beam 242b using a second antenna port 244b associated with a second antenna 218b. As described further herein, the first wireless device 102 can perform antenna-aware energy-aware reservation, which can enable improved performance when switching between antenna ports involved in a transmission.

[0045] The term“beam” can be used in various contexts in this disclosure. A beam can be used to represent a set of gains and / or phases (e.g., precoding weights or co-phasing weights) applied to antenna elements in (or associated with) a wireless device for transmission or reception. The term“beam” can also refer to an antenna or radiation pattern of a signal transmitted when gains and / or phases are applied to the antenna elements. Other references to a beam can include one or more properties or parameters associated with an antenna (radiation) pattern, such as angle of arrival (AoA), angle of departure (AoD), gain, phase, directivity, beam width, beam direction (relative to a reference plane) in terms of azimuth and elevation angles, peak-to-sidelobe ratio, or an antenna port associated with an antenna (radiation) pattern. The term“beam” can also refer to the associated number and / or configuration of antenna elements (e.g., uniform linear array, uniform rectangular array, or other uniform array).

[0046] Figure 2 An example transceiver design is shown. It will be appreciated that other transceiver designs or architectures can be applied in conjunction with aspects of the present disclosure.

[0047] In certain cases, compliance with RF exposure limits can be performed as a time-averaged RF exposure evaluation over a specified operating (mobile) time window associated with the RF exposure limits. The RF exposure limits can specify a time-averaged RF exposure metric (e.g., SAR and / or PD) over an operating time window. As an example, the Federal Communications Commission (FCC) specifies certain SAR limits (general public exposure) to be 0.08 W / kg, averaged over the whole body, and a peak spatially-averaged SAR to be 1.6 W / kg, averaged over any 1-gram tissue (defined as a tissue volume in the shape of a cube), for sub-6 GHz bands, while certain PD limits are 1 mW / cm2averaged over any 1 cm2area, averaged over the whole body, and a peak spatially-averaged PD is 4 mW / cm2averaged over any 1 cm2area, averaged over the whole body, for mmWave bands (e.g., 60 GHz bands). 2 As an example, the FCC specifies certain SAR limits (general public exposure) to be 0.08 W / kg, averaged over the whole body, and a peak spatially-averaged SAR to be 1.6 W / kg, averaged over any 1-gram tissue (defined as a tissue volume in the shape of a cube), for sub-6 GHz bands, while certain PD limits are 1 mW / cm2averaged over any 1 cm2area, averaged over the whole body, and a peak spatially-averaged PD is 4 mW / cm2averaged over any 1 cm2area, averaged over the whole body, for mmWave bands (e.g., 60 GHz bands). 2 As an example, the FCC specifies certain SAR limits (general public exposure) to be 0.08 W / kg, averaged over the whole body, and a peak spatially-averaged SAR to be 1.6 W / kg, averaged over any 1-gram tissue (defined as a tissue volume in the shape of a cube), for sub-6 GHz bands, while certain PD limits are 1 mW / cm2averaged over any 1 cm2area, averaged over the whole body, and a peak spatially-averaged PD is 4 mW / cm2averaged over any 1 cm2area, averaged over the whole body, for mmWave bands (e.g., 60 GHz bands). 2 As an example, the FCC specifies certain SAR limits (general public exposure) to be 0.08 W / kg, averaged over the whole body, and a peak spatially-averaged SAR to be 1.6 W / kg, averaged over any 1-gram tissue (defined as a tissue volume in the shape of a cube), for sub-6 GHz bands, while certain PD limits are 1 mW / cm2averaged over any 1 cm2area, averaged over the whole body, and a peak spatially-averaged PD is 4 mW / cm2averaged over any 1 cm2area, averaged over the whole body, for mmWave bands (e.g., 60 GHz bands).

[0048] The RF exposure limits and / or corresponding averaging time windows can vary based on the frequency band. In certain aspects, the RF exposure limits and / or corresponding averaging time windows can be specific to a particular geographic region or country, such as the United States, Canada, China, or the European Union. In some cases, the RF exposure limits can specify a maximum allowed RF exposure that can be encountered without time averaging. In such scenarios, the maximum allowed RF exposure can correspond to a maximum allowed transmit power that can be used by a wireless device.

[0049] Figure 3This is a graph 300 showing transmit power versus time (P(t)) as it changes with an operating (e.g., rolling or moving) time window (T) associated with RF exposure limits. A wireless device (e.g., first wireless device 102) can assess RF exposure compliance over the operating time window 302(T) based on past RF exposures (e.g., transmit power reports) in past time intervals 304 of the time window 302 and future time intervals 306. The wireless device can determine the maximum permissible transmit power for the future time interval 306 that meets the time-averaged RF exposure limits based on past RF exposures used in past time intervals 304. The wireless device can perform such a time-averaged assessment as the time window 302 moves over time (e.g., in the next future time interval 308), where past time intervals 304 now include the previous future time interval 306.

[0050] Maximum time average transmit power limit (P limit This represents the maximum transmit power that the wireless device can continuously transmit within the duration of the operating time window 302(T) that complies with RF exposure limits. For example, the wireless device transmits at P during the third time window 302c. limit Transmissions are made continuously such that the time-averaged transmit power over the time window (e.g., the third time window 302c) is equal to P, which meets the time-averaged RF exposure limit. limit .

[0051] In some cases, instantaneous transmit power can exceed P at certain transmission moments. limit For example, as shown in the first time window 302a and the second time window 302b. In some cases, the wireless device can use P max Send, P max This could be the maximum instantaneous transmit power supported by the wireless device, the maximum instantaneous transmit power that the wireless device can output, or the maximum instantaneous transmit power permitted by standards or regulatory agencies (e.g., maximum output power P). CMAX In some cases, wireless devices may transmit at a rate less than or equal to P during certain transmission opportunities. limit Transmit at the transmit power, for example, as shown in the first time window 302a.

[0052] In some cases, when sending data above P within the time window limit At this time, reserved power can be used to achieve continuous transmission within a time window (T). As shown in the second time window 302b, the transmit power can be adjusted from P. max Back to reserved power (P) reserve), such that the wireless device can maintain continuous transmissions (e.g., maintain a radio connection with a receiving entity) during the time window in compliance with the time-averaged RF exposure limit. In the third time window 302c, the wireless device can increase the transmit power to P limit In some cases, P reserve may be allowed for certain transmissions (e.g., control signaling and / or high priority communications, low latency communications, highly reliable communications, etc.). P reserve may be used to reserve transmit power for certain transmissions (e.g., control signaling) for at least a portion of the time window 302. P reserve may also be referred to as a “control power level” or a “control level.”

[0053] In the second time window 302b, the wireless device can transmit at P max for a duration of time, P max may be transmitted at P reserve for a duration of time, P limit may be transmitted at P reserve for a duration of time, P limit such that the area of the transmit power (P(t)) in the second time window 302b is equal to the area of P reserve over the time window T. Such an area can be considered using 100% of the energy (transmit power or exposure) to remain in compliance with the time-averaged RF exposure limit. Without reserving power P max , the transmitter can transmit at P max for a portion of the time window, where the transmitter is off for the remainder of the time window to ensure compliance with the time-averaged RF exposure limit.

[0054] In some aspects, the wireless device can transmit at a power higher than P limit but less than P max in the time-averaged pattern shown in the second time window 302b. While a single transmission burst is shown in the second time window 302b, it should be understood that the wireless device can instead utilize multiple transmission bursts within the time window (T), where the transmission bursts are separated by periods during which the transmit power remains at or below P reserve . Further, it should be understood that the transmit power of each transmission burst can vary (within the burst and / or compared to other bursts) and that at least a portion of the transmission burst can be transmitted at a power higher than P limit .

[0055] In certain aspects, the wireless device can transmit at a power less than or equal to a fixed power limit (e.g., P limittransmit at a power less than or equal to P limit without regard to past exposure and / or past transmit power in terms of time-averaged RF exposure. For example, the wireless device can use a lookup table to transmit at a power less than or equal to P limit including one or more values of P limit depending on the transmit frequency, transmit antenna, radio configuration (single radio or multiple radios), and / or RF exposure scenario (e.g., a device state index corresponding to head exposure, body or torso exposure, limb or hand exposure, and / or hotspot exposure) encountered by the wireless device. Examples of RF exposure scenarios include a case where the wireless device is transmitting RF signals in close proximity to human tissue, such as a user’s head, hand, or body (e.g., torso), or a case where the wireless device is being used as a hotspot away from human tissue. Thus, RF exposure can be managed as a time-averaged RF exposure evaluation (e.g., as shown in FIG. 2), using a lookup table or a flat or maximum value, or using another strategy or algorithm, where the particular process of managing RF exposure can be referred to herein as an RF exposure control scheme. Figure 3

[0056] ​For certain aspects, a wireless device can exhibit or be configured with a transmission duty cycle. The wireless device can determine a transmit power level and / or a reservation power level that complies with a time-averaged RF exposure limit based on the duty cycle. The transmission duty cycle can indicate a fraction (e.g., 5 ms) of a particular time period (e.g., 500 ms) in which the wireless device transmits RF signals. The duty cycle can be a ratio of the fraction to the particular time period (e.g., 5 ms / 500 ms), where the duty cycle can be expressed as a number from 0 to 1. For example, in a first time window 302a, the duty cycle can be greater than 50% of the duration of the time window (T), while in a second time window 302b, the duty cycle can be equal to 100% of the duration of the time window (T). In certain cases, the duty cycle can be standardized (e.g., predetermined) with a particular RAT and / or vary over time, e.g., due to changes in radio conditions, mobility, and / or user behavior. As an example, certain RATs can specify an uplink duty cycle in the form of a time division duplex (TDD) configuration, such as a TDD uplink-downlink (UL-DL) slot pattern in 5G NR or a similar TDD pattern in E-UTRA or UMTS. In 5G NR, a TDD UL-DL slot pattern can specify a number of uplink slots and a corresponding location in time associated with the uplink slots in a sequence of slots, such that the total number of uplink slots indicates a duty cycle relative to the total number of slots in the sequence. In certain aspects, the duty cycle can correspond to an actual duration of past transmissions, e.g., scheduled or used within the TDD UL-DL slot pattern. For example, although a wireless device can be configured with a TDD UL-DL slot pattern, the wireless device can transmit RF signals using a portion or subset of the UL slots. Thus, the duty cycle of the wireless device can be less than a maximum available duty cycle corresponding to the TDD UL-DL slot pattern.

[0057] In certain wireless communication systems (e.g., E-UTRA and / or 5G NR), there are RF emission limits for the output power of a wireless device, e.g., to mitigate inter-device interference, and these RF emission limits can be applied in addition to or instead of the RF exposure limits described herein. As an example, under the 5G NR standard, a wireless device is allowed to set its configured maximum output power P CMAX,f,c for a carrier f of a serving cell c in each slot for certain communications CMAX,f,c is set within the following limits:

[0058] P CMAX_L,f,c ≤ P CMAX,f,c ≤ P CMAX_H,f,c

[0059] where P CMAX_L,f,c and P CMAX_H,f,cThe maximum output power (MPR) can be determined based on various parameters, including, for example, power level, frequency band, maximum power reduction (MPR), and / or additional MPR (A-MPR). In some cases, the MPR associated with different transmission paths (e.g., TX path 214) can vary across the wireless device, and therefore, the maximum output power associated with different transmission paths can vary. The maximum output power of the active carrier (e.g., component carrier) can depend on the antenna port selection, power level, carrier frequency band and frequency, power back-off (e.g., MPR) to account for hardware path characteristics, etc. The wireless device can apply parameters to determine the maximum output power (P). CMAX Any of the various functions of a wireless device, where these functions can be specific to a particular communication scenario, such as carrier aggregation, multiple connectivity (e.g., NR-Dual Connectivity (NR-DC)), V2X, uplink (UL) multiple-input multiple-output (MIMO), etc. In some respects, the wireless device can select the maximum output power as P. CMAX The minimum value (e.g., lowest value) and another output power value (e.g., P) PUSCH P PUCCH P SRS and / or P PRACH It can be determined based on various parameters, such as the target received power, path loss, and bandwidth at the receiving entity (e.g., base station), and in some cases, power control adjustment parameters.

[0060] The antenna ports of wireless devices can have varying RF exposure limits (e.g., different P...). limit ) and / or output power parameters (e.g., P CMAX Wireless devices can switch from transmitting using one antenna (or antenna array, e.g., for beamforming or MIMO communication) to transmitting using another antenna (or antenna array), e.g., as referred to herein. Figure 2 As described. Wireless devices can frequently switch between antenna ports for any reason, such as RF exposure budget (e.g., SAR), path loss, traffic activity, wireless device mobility, etc. In some cases, a wireless device may switch to using a different antenna port for transmission in response to detecting that the corresponding antenna port provides better communication performance (due to channel conditions and / or RF exposure budget). For example, a wireless device may monitor the channel conditions (and / or other factors including RF exposure budget) associated with an antenna port and select the antenna port exhibiting the best channel conditions (as an example) for an upcoming transmission. For example, an antenna port may be selected to maximize throughput, minimize power usage, and / or reduce RF exposure. Some factors that may influence antenna port selection include path loss, maximum output power (e.g., P), etc. CMAXTransmit power backoff parameters (e.g., power headroom report (PHR)), duty cycle, and / or RF exposure budget (e.g., SAR and / or PD budget). A power management algorithm (e.g., RF exposure manager 106) can determine the maximum allowable transmit power for a future time interval (e.g., future time interval 306) based on the RF exposure budget and / or RF exposure limit associated with the antenna port.

[0061] As described herein, wireless devices can be evaluated (e.g., as a time-averaged evaluation of past transmit power or as a maximum permissible transmit power (P)). limit Transmit power within the operating time window (e.g., time window 302) is adjusted to comply with time-averaged RF exposure limits. In some cases, wireless devices may reserve power within the time window for certain communications (e.g., high-priority communications and / or services or certain high-power transmissions). Figure 3 The P described in reserve When determining the amount of energy reserved for this type of communication, the wireless device may consider the attributes associated with the active antenna port (e.g., the first antenna port). When switching to a different antenna port, for example due to different RF exposure limitations associated with the new antenna port (e.g., P...), limit The energy reserved by the device for a previous antenna port may be insufficient to meet the energy specifications of a new active antenna port (e.g., a second antenna port). In such cases, the wireless device may not allocate enough energy to transmit certain lower-priority communications or maintain a target power level or maintain high-priority communications.

[0062] In this scenario, in response to switching to a different antenna port, the wireless device can allocate only a portion of the energy requested for certain communications. Consequently, communications relying on reserved energy may experience performance degradation (e.g., reduced transmit power may result in reduced throughput, increased latency, and / or reduced range) and / or temporary suspension of transmission to comply with RF exposure limits. If the wireless device uses a lower-requirement antenna port (e.g., higher P...),... limit and / or P CMAX If insufficient power is reserved for communications associated with reserved energy (e.g., high-priority services and high-power buffers) during the activity interval, the wireless device may not have enough power for antenna ports that require higher power (e.g., lower P). limit and / or P CMAXsubsequent intervals of activity. The wireless device can spend the SAR budget on low priority data. This can result in the wireless device not having enough energy to achieve the target power level. In some cases, for example, performance of high priority services that rely on reserved energy, such as Voice over LTE (VoLTE) and / or Voice over NR (VoNR), can degrade, or calls can drop.

[0063] As an example, during a period in which the wireless device uses a lower normalized reserved energy for a high priority service and / or a high power buffer, the wireless device can not have enough energy set aside for a subsequent period in which the wireless device uses a higher normalized reserved energy for the high priority service and / or the high power buffer. For example, assume the wireless device is transmitting via a first antenna port, where P CMAX is 26 dBm for the first antenna port, P limit is 23 dBm for the first antenna port, and the duty cycle is 0.1. When using the first antenna port, the wireless device can reserve energy using these power attributes associated with the first antenna port in each future time interval associated with the rolling time window for the high priority service. When the wireless device switches to transmitting using a second antenna port, for example due to different transmit power attributes associated with the second antenna port, the energy reserved using the power attributes associated with the first antenna port can not be sufficient for the high priority service, where P CMAX is 23 dBm for the second antenna port, and P limit is 14 dBm. Effectively, the reserved energy occupies a greater portion of the energy available on the second antenna port relative to the first antenna port. For example, when the second antenna port is active, the wireless device can reserve more than four times as much energy for the high priority service and / or the high power buffer (e.g., the target power level). Thus, the lower reserved energy can result in reduced performance and / or temporary suspension in communications, for example, in order to focus on transmitting the high priority service and / or RF exposure budget to replenish as the running time window moves over time.

[0064] Example antenna-aware energy reservation for radio frequency exposure compliance

[0065] Aspects of the disclosure provide apparatuses and methods for antenna-aware energy reservation. When determining energy reservations for certain communications (e.g., high priority communications and / or high power buffers), a wireless device can consider transmit power attributes associated with multiple antenna ports. As an example, the wireless device can maintain a history buffer of information associated with multiple antenna ports, such as all antenna ports available to the wireless device or a subset of such antenna ports, as further described herein. The history buffer can include any of various information for each antenna port, such as a maximum transmit power (e.g., PCMAX ), maximum time-averaged transmit power (e.g., P limit ), target power, etc. The wireless device can determine a reserve energy for certain communications based on the history buffer. For example, the wireless device can set the reserve energy to an amount that would be used to act on an antenna port with the most stringent transmit power properties (e.g., lowest maximum transmit power and / or lowest maximum time-averaged transmit power). In this case, the wireless device can switch to the most demanding antenna port in terms of transmit power characteristics and maintain an expected performance level for certain communications (e.g., communications that rely on the reserve energy).

[0066] The apparatuses and methods for antenna-aware energy reservation described herein can provide various advantages. The apparatuses and methods described herein can allow a wireless device to reserve sufficient energy for certain communications (e.g., high-priority services and / or high-power transmission bursts) regardless of the antenna port being used for the communications, thereby allowing the wireless device to switch between antenna ports without impacting the performance of certain communications associated with the reserve energy. For example, the wireless device can reserve a sufficient amount of energy for high-priority services, which can ensure that the performance and / or quality of such services is maintained even when the wireless device switches between antenna ports. In such cases, the wireless device can experience increased throughput, reduced latency, and / or increased communication range due to the antenna-aware reservation described herein.

[0067] In certain aspects, the wireless device can maintain a history buffer associated with certain antenna ports (e.g., antenna ports 244a, 244b) in order to determine one or more energy reservations for certain communications. The list of antenna ports can include any of various sets of antenna ports, such as recently used antenna ports, currently active antenna ports, antenna ports that have been encountered as active, or all antenna ports that the wireless device is equipped with or is capable of using.

[0068] The recently used antenna ports can include antenna ports that have participated in transmissions in a particular time period, such as a recent past time period (e.g., past time interval 304 or any other suitable time period), and / or the most recent N antenna ports to be used, where N is a positive integer. The time period can correspond to an inactivity time threshold as described further herein.

[0069] The currently active antenna ports can include antenna ports that will participate in transmissions in a particular time interval (e.g., future time interval 306). As an example, the wireless device can obtain a list of currently active antenna ports and determine the most demanding antenna port of these antenna ports. The wireless device can base the reserve energy on P CMAX and P limitThe wireless device can determine an energy reservation for the most demanding antenna port.

[0070] It has been encountered that the active antenna port can include an antenna port that has been active during a time that the wireless device has been operating, such as when the wireless device has been operating and / or when the wireless device transitions from a sleep state, idle state, or low power state. For example, the history buffer can be empty or set with certain antenna ports. Each time the wireless device encounters a new antenna port, the wireless device can check whether the new antenna port is more demanding than other antenna ports. The wireless device stores the characteristics of the most demanding antenna port (e.g., semi-static P CMAX and / or P limit ) and uses its characteristics to reserve energy.

[0071] In certain aspects, the wireless device can obtain a list of all configured antenna ports (e.g., in a static configuration) and use the most demanding antenna port to determine an energy reservation.

[0072] The history buffer can include information associated with the antenna ports in the list. The information can include a maximum time average transmit power - e.g., a P limit , a target power, a maximum output power (e.g., P CMAX ), a last time the antenna port was used, a duration of a time average time window (e.g., time window 302) associated with the antenna port, or any combination thereof. The information can be used to determine an energy reservation for certain communications regardless of which antenna port is used for transmissions between the antenna ports in the list.

[0073] For example, the wireless device can identify the antenna port in the list that has the highest RF exposure limit (e.g., lowest P limit ) and / or maximum output power (e.g., lowest P CMAX ). The most demanding antenna port can be determined based on a relationship between the maximum output power (P CMAX ) and the maximum time average transmit power (P limit ). For example, the most demanding antenna port can be determined by identifying the antenna port that has the largest difference between the maximum output power (P CMAX ) and the maximum time average transmit power (P limit ), where each difference (e.g., ratio ap ) associated with the antenna port can be determined by the following expression:

[0074] ratio ap = P CMAX_dB,ap - Plimit_dB,ap

[0075] where ratio ap is the power difference associated with a particular antenna port, P CMAX_dB，ap is the maximum output power associated with a particular antenna port in decibel-milliwatts (dBm), and P limit_dB，ap is the maximum time-averaged transmit power associated with a particular antenna port in dBm.

[0076] It will be appreciated that the wireless device can identify the antenna port in the history buffer to determine the appropriate energy reservation based on any of a variety of criteria, including the highest demanding antenna port and / or other criteria. For example, the wireless device can identify the antenna port with the greatest propensity (or likelihood) of being involved in transmissions, e.g., based on past traffic history. In some cases, the wireless device can identify the antenna port with the best channel conditions among the antenna ports in the history buffer for determining the energy reservation. In certain cases, the wireless device can identify the antenna port with the greatest RF exposure budget for determining the energy reservation.

[0077] The wireless device can determine the reservation energy that would be appropriate for the selected antenna port (e.g., the highest demanding antenna port) based on the transmission attributes associated with that antenna port, such as the duty cycle, P limit , the duration of the time window, etc. The wireless device can set aside sufficient SAR / MPE energy for each future time interval (e.g., future time interval 306) of the highest demanding antenna port so that the wireless device is able to communicate via the highest demanding antenna port in the event that the wireless device switches to using that antenna port.

[0078] Since the wireless device has set aside sufficient energy for the highest demanding antenna port, the transmit power can be maintained at the reservation level when the wireless device switches to an antenna port with a higher normalized energy standard to reach the target transmit power. The wireless device can maintain the expected transmission quality regardless of the antenna port used and avoid performance degradation or dropped calls when switching to a more demanding antenna port.

[0079] Figure 4is a diagram illustrating an example history buffer 400. In this example, the history buffer 400 can be a list of antenna ports for which antenna-aware energy reservation and information 402 associated with those antenna ports were evaluated. The history buffer 400 can include information 402 associated with each of antenna ports 404a-N (collectively, “antenna ports 404”), where N is the total number of antenna ports in the history buffer 400. The wireless device can occasionally add antenna ports to the history buffer 400 and / or remove antenna ports from the history buffer 400. As an example, the antenna ports 404 can include recently used antenna ports as described herein, where the wireless device can only keep active antenna ports in the history buffer 400.

[0080] As shown, the information 402 can include an antenna port identifier (AP ID), a maximum time-averaged transmit power (e.g., P limit or P lim ), a target transmit power (which can be equal to P CMAX ), a maximum output power (P CMAX ), an indication of the last time the antenna port was used, (optionally) a duration of a time-averaging time window (e.g., time window 302) associated with the antenna port. The AP ID can be a unique identifier associated with a particular antenna, which can be used to maintain antenna ports in the history buffer (e.g., add or remove antenna ports).

[0081] The target transmit power can be a requested transmit power associated with the antenna port. For example, a modem (e.g., modem 212) that controls transmissions via the antenna port or an exposure control solution (e.g., an inner loop or a separate control solution) can request a target transmit power for a future time interval (e.g., future time interval 306) to a centralized controller, such as RF exposure manager 106 (which is sometimes referred to as an outer loop). In some cases, the target transmit power can be less than or equal to P CMAX or P max , as described herein with reference to Figure 3 .

[0082] The time-averaging time window can vary based on the frequency band used for the transmission. Since certain antenna ports can be capable of transmitting in particular frequency bands (e.g., sub-6 GHz frequency bands and / or millimeter wave frequency bands), the time window can vary based on the antenna ports involved in the transmission. For example, assuming that the antenna ports are only capable of transmitting in sub-6 GHz frequency bands, the time window can correspond to the RF exposure limit for sub-6 GHz frequency bands.

[0083] The indication of the last time the antenna port was used, which can be referred to as an inactivity time, can include a timestamp associated with the last time the antenna port was engaged in a transmission. In some cases, the inactivity time associated with an antenna port can include a time counter that tracks a duration in which the particular antenna port was not engaged in a transmission or refrained from being used for a transmission. The inactivity time associated with an antenna port can be used to determine whether to remove the antenna port from the history buffer. For example, if the inactivity time is greater than or equal to a threshold, the wireless device can remove the antenna port (and its corresponding information) from the history buffer.

[0084] The wireless device can add or remove an antenna port from the history buffer based on any of a variety of criteria. As an example, the wireless device can add an antenna port to the history buffer in response to the antenna port being or expected to be engaged in a transmission. When an antenna port is expected to be engaged in a transmission, e.g., in a future time interval, the wireless device can add (in some cases, re-add) the antenna port to the history buffer and adjust the reserved energy accordingly. The wireless device can add or remove an antenna port from the history buffer in response to a change in any of a variety of criteria, such as traffic activity (e.g., greater or lesser traffic), traffic type (e.g., voice, gaming traffic, streaming content, etc.), expected latency (e.g., greater or reduced latency), user behavior, mobility, time of day, etc. In some cases, the history buffer can be configured to permanently (or semi-statically) include (or exclude) particular antenna ports and their corresponding information.

[0085] As an example of maintaining the history buffer, assume that the wireless device is transmitting via one or more first antenna ports (e.g., first antenna ports 244a) and, when the wireless device switches (or expects to switch) to using one or more second antenna ports (e.g., second antenna ports 244b), the wireless device can update the history buffer with the inactivity time associated with the first antenna ports. In some cases, in response to switching to the second antenna ports or expecting to switch to the second antenna ports (e.g., in a future time interval), the wireless device can identify any outdated antenna ports in the history buffer and remove such antenna ports from the history buffer. If the second antenna ports are already in the history buffer, the wireless device can update the information associated with the antenna ports in the history buffer (if there are any updates to such information) in response to switching to the second antenna ports. For example, the wireless device can update the P limit , P CMAX, inactivity time, and / or time average time window. If the second antenna port is not in the history buffer, the wireless device can add the second antenna port to the history buffer and corresponding information if there is enough space in the history buffer. If there is not enough space in the history buffer, the wireless device can remove the oldest (or stale) antenna port (e.g., based on the corresponding inactivity time and / or time in the history buffer) until there is enough space to add the second antenna port to the history buffer.

[0086] A stale antenna port can mean an antenna port that has not been used for transmission for a particular time period (e.g., an inactivity time threshold T inactivity ), where the inactivity time threshold can be a fixed or dynamic duration of time. In some cases, the inactivity time threshold can correspond to a time average time window (e.g., time window 302) associated with that particular antenna port or any other antenna port (in the history buffer). As an example, the inactivity time threshold can be determined according to the following expression:

[0087] T inactivity = T RFexposureWindow · F

[0088] where T RFexpsireWomdpw is the time average time window associated with the RF exposure limit, and F is a scaling factor used to adjust the inactivity time threshold. As an example, F can be 20% more than the time average time window, equal to 1.2.

[0089] Figure 5 A first plot 500A showing example transmit powers over time and a second plot 500B showing corresponding requested normalized exposure, with energy reserved as described herein, is depicted. In this example, the wireless device can have a first antenna port (e.g., first antenna port 244a) and a second antenna port (e.g., second antenna port 244b). For the first antenna port, P CMAX is 26 dBm, P limit is 23 dBm, and the duty cycle is 0.1, while for the second antenna port, P CMAX is 23 dBm, P limit is 14 dBm, and the duty cycle can (assume to be) the same.

[0090] In a first transmission occasion 502, when the first antenna port is active (e.g., participating in transmission), the wireless device can leave enough energy (e.g., P CMAX is 23 dBm, and P limit is 14) for the second antenna port based on the transmission characteristics associated with the second antenna port. In certain aspects, the reserved energy (which can be normalized to an RF exposure limit, such as Plimit ) can include a first reserved energy (e.g., NE_DynRsv = A) for certain communications (e.g., high priority communications) and / or a second reserved energy (e.g., NE_HpBuf = B) for high power transmissions (e.g., up to P Figure 3 max of up to P max Figure 5 As shown, the total reserved energy can equal X as a sum of A and B associated with the respective reservations. For example, the second antenna port can be the most demanding antenna port (or any other suitable criteria) selected among the antenna ports in the history buffer (e.g., history buffer 400). The wireless device can treat the energy left for the second antenna port as extra energy (e.g., NE_DynRsv_Shadow = C - A and / or NE_HpBuf_Shadow = D - B) added to the respective base reservations (e.g., NE_DynRsv and / or NE_HpBuf). The reservation for the second antenna port can equal C for NE_DynRsv and D for NE_HpBuf, where the total reserved energy can equal Y as a sum of C and D associated with the respective reservations, as shown. Figure 5 As shown, the total reserved energy can equal X as a sum of A and B associated with the respective reservations. For example, the second antenna port can be the most demanding antenna port (or any other suitable criteria) selected among the antenna ports in the history buffer (e.g., history buffer 400). The wireless device can treat the energy left for the second antenna port as extra energy (e.g., NE_DynRsv_Shadow = C - A and / or NE_HpBuf_Shadow = D - B) added to the respective base reservations (e.g., NE_DynRsv and / or NE_HpBuf). The reservation for the second antenna port can equal C for NE_DynRsv and D for NE_HpBuf, where the total reserved energy can equal Y as a sum of C and D associated with the respective reservations, as shown.

[0091] In certain aspects, the wireless device can update the allocation of reservations, update the history buffer, and / or update how the history buffer is maintained, e.g., in response to satisfying one or more particular criteria. For example, if the wireless device detects that a reservation is not fully used (e.g., partially used and / or not used for future transmissions), the wireless device can temporarily eliminate the reservation or adjust the amount of reservation allocated to a particular antenna port identified based on the history buffer. In some cases, the wireless device can select a different approach to maintaining the history buffer in response to detecting that a reservation is not fully used. For example, the wireless device can transition from maintaining a history for all antenna ports to a subset of antenna ports, such as the various subsets described herein.

[0092] Figure 6 This is a flowchart illustrating an example operation 600 for wireless communication. Operation 600 can be performed, for example, by a wireless device (e.g., the first wireless device 102 in wireless communication system 100). Operation 600 can be implemented in one or more processors (e.g., Figure 2 Software components executed and running on the processor 210 and / or modulator 212. Furthermore, the transmission and / or reception of signals by the wireless device in operation 600 may be achieved, for example, by one or more antennas (e.g., Figure 2 This can be achieved via antenna 218. In some aspects, the wireless device can transmit and / or receive signals via a bus interface of one or more processors (e.g., processor 210 and / or modem 212), which acquire and / or output signals for receiving or transmitting.

[0093] Operation 600 may optionally begin at block 602, where the wireless device can obtain information (e.g., information 402) associated with multiple antenna ports (e.g., antenna port 404). To obtain the information, the wireless device can track the information as a historical buffer (e.g., historical buffer 400) associated with the multiple antenna ports. The wireless device can maintain the historical buffer associated with the antenna ports, as referenced herein. Figure 4 As described. For example, a wireless device may occasionally add an antenna port to the history buffer and / or remove an antenna port from the history buffer in response to any of the various standards (such as when the wireless device switches to a new antenna port or when an antenna port becomes obsolete).

[0094] At box 604, the wireless device can determine one or more reservations (e.g., such as...) based at least in part on this information. Figure 5 The standardized energy P described in reserve(or reservation). For example, a wireless device can identify the most requested antenna port (and / or any other suitable criterion associated with the antenna port) in a history buffer, and the wireless device can determine the reservation of the most requested antenna port regardless of whether the most requested antenna port is currently active. One or more reservations may include a first reservation allocated to certain communications (e.g., high-priority communications) and / or a second reservation allocated to high-power transmission bursts (or any other suitable transmissions). In some cases, a wireless device may allocate reservations per cell group (e.g., carrier group), per cell (e.g., carrier), and / or per subcarrier (e.g., bandwidth portion or subchannel). The wireless device may be able to communicate with one or more wireless networks via multiple cell groups, cells, and / or subcarriers via one or more subscriptions (e.g., via multiple subscriber identity modules (SIMs) or universal SIMs (USIMs)). The reservation may correspond to the area under transmit power over time (e.g., P over a specific duration). reserve ), where the region may include power constraints (e.g., P) over a time-averaging window. limit A portion (or all) of that area.

[0095] In block 606, the wireless device may transmit a first signal via a first antenna port (e.g., first antenna port 244a) at a first transmit power determined at least in part based on the one or more reservations, while maintaining at least a portion of the one or more reservations for future transmission via a second antenna port (e.g., second transmission timing 504). For example, the wireless device may transmit to a second wireless communication device (e.g., Figure 1 (any of the second wireless devices 104 depicted) transmits a first signal. The first signal may indicate (or carry) any of various types of information, such as data or control information. A transmit power area associated with a reservation may be allocated to the transmission (e.g., for a specific duration with P). reserve All or part of the associated area. The wireless device may maintain (e.g., retain or preserve) a reserved portion for future transmissions via the second antenna port. As described herein, the reservation maintained for future transmissions can be determined based on certain information associated with the second antenna port.

[0096] In some respects, this information may include any of the various parameters associated with the transmission characteristics of the antenna port, such as those referenced herein. Figure 4 As described. For example, for each of a plurality of antenna ports, this information includes the maximum transmit (output) power (e.g., P). CMAX ) and maximum time-averaged transmit power (e.g., P limitan indication of a difference between a maximum transmit (output) power and a maximum time-averaged transmit power. In certain aspects, for each of the plurality of antenna ports, the information includes an indication of a relationship between the maximum transmit (output) power and the maximum time-averaged transmit power (e.g., ratio ap = P CMAX_dB,ap – P limit_dB,ap ). In some cases, for each of the plurality of antenna ports, the information includes an indication of a reservation to be used for the respective antenna port. For each of the plurality of antenna ports, the information can include an identifier associated with the respective antenna port (e.g., AP ID), a maximum time-averaged transmit power associated with the respective antenna port (e.g., P limit ), a target transmit power (e.g., which can be less than or equal to P CMAX ), an indication of when the respective antenna port was last used for transmission (e.g., inactivity time), a duration of a time-averaging time window associated with the respective antenna port (e.g., time window 302), or a combination thereof.

[0097] For certain aspects, to determine a reservation, the wireless device can identify a particular one of the antenna ports in the history buffer based on any of a variety of criteria (e.g., a highest demanding antenna port), and the wireless device can determine a reservation for the particular antenna port regardless of whether the antenna port is actively transmitting or expected to actively transmit. As an example, the wireless device can determine a maximum (e.g., a largest) value of a power difference (e.g., ratio ap = P CMAX_dB,ap – P limit_dB,ap ) associated with the plurality of antenna ports. The wireless device can determine a reservation based on the maximum value associated with the respective antenna port. For example, the wireless device can determine a reservation that would allow compliance with an RF exposure limit (e.g., P limit ) associated with the respective antenna port.

[0098] In certain aspects, the wireless device can track a history buffer associated with antenna ports. The wireless device can update the history buffer periodically and / or in response to certain criteria, such as encountering a new antenna port, expecting a new antenna port, switching to a different antenna port, and the like. For example, the wireless device can maintain certain antenna ports in the history, such as recently used antenna ports. The plurality of antenna ports can be a set of antenna ports that have participated in transmissions over a period of time. The period of time can be based on a time-averaging time window associated with an RF exposure limit (e.g., time window 302 and / or T inactivity = T RFexposureWindow•F). The multiple antenna ports can be a set of antenna ports that are active when the reservation is determined (or expected to be active, for example, in a future time interval). In some cases, an antenna port is considered active if it will be involved in transmissions during a specific time interval (e.g., future time interval 306). The multiple antenna ports can also be a set of antenna ports that have been active during the time the wireless device has been operating. The time the wireless device has been operating corresponds to the time when the wireless device has been powered on or resumed from a specific state (e.g., sleep mode, idle mode, or flight mode). The multiple antenna ports can include all antenna ports of the wireless device.

[0099] The wireless device can determine a first transmit power to comply with RF exposure limits while maintaining reservations for future transmissions (e.g., transmissions in future time interval 306 or a second transmission timing 504). For example, the wireless device can determine the first transmit power for a future time interval (e.g., future time interval 306) based at least in part on transmit power history (e.g., transmit power associated with past time interval 304) and the reservations determined at box 604.

[0100] In some respects, wireless devices can switch to transmitting via different antenna ports, for example, as referenced herein. Figure 5 As described herein, a wireless device may transmit a second signal via a second antenna port (e.g., second antenna port 244b) using at least a reserved portion of the second transmit power, for example, as described herein. Figure 5 As described. In some cases, a wireless device can transmit a second signal at a different time than the first signal, such as... Figure 5 As shown. For example, a wireless device may transmit a first signal via a first antenna port in a first transmission time 502, and a wireless device may transmit a second signal via a second antenna port in a second transmission time 504. In some cases, reservation can facilitate transmission via multiple antenna ports (e.g., the first antenna port and the second antenna port) in the same time interval (e.g., future time intervals 306, 308).

[0101] In some respects, reservations may include a first reservation allocated to certain communications (e.g., high-priority communications) and / or a second reservation allocated to high-power transmission bursts (or any other suitable transmissions), such as Figure 3 The bursts described in the text, where high-power transmission bursts can correspond to bursts with power greater than P limittransmissions of a transmit power or any other threshold power. The reservation can be associated with any of various types of (or certain) communications and / or transmissions. For example, a wireless device can reserve for certain communications and / or transmissions, such as high priority communications and / or high power transmission bursts. The reservation can be associated with a particular type of transmission, where the particular type of transmission includes transmissions associated with a high priority service relative to a plurality of priorities, where the priority can correspond to a quality of service parameter and / or a particular configuration that identifies various priorities. For example, the particular type of transmission (and / or corresponding high priority service) can include voice traffic (e.g., LTE voice or NR voice), video traffic, gaming traffic, video conference traffic, over-the-top communication (OTTC) traffic, control signaling (e.g., uplink control information, radio resource control signaling, medium access control signaling, etc.), hybrid automatic repeat request (HARQ) feedback, or any combination thereof.

[0102] In certain aspects, the wireless device can update the reservation, update the history buffer (e.g., remove or add an antenna port from the history buffer), and / or update how the history buffer is maintained (e.g., how to add or remove an antenna port from the history buffer) in response to one or more criteria being satisfied. As an example, the wireless device can update one or more reservations (e.g., increase or decrease the reservation) in response to one or more criteria being satisfied. In some cases, the one or more criteria can be satisfied when more of the reservation is not fully utilized for the second antenna port (e.g., if the reservation usage is less than or equal to a particular threshold). In this case, the wireless device can decrease the reservation allocation for the second antenna port. Additionally or alternatively, the wireless device can update the history buffer or select a different approach to maintaining the history buffer (e.g., a different subset of antenna ports). In certain cases, the one or more criteria can be satisfied when the reservation usage for the second antenna port is greater than or equal to a threshold. In this case, the wireless device can increase the reservation allocation for the second antenna port. Additionally or alternatively, the wireless device can ensure that the second antenna port remains in the history buffer. In certain aspects, the one or more criteria can be satisfied to trigger a re-determination of the antenna ports associated with the reservation and corresponding reservation level when a change is made to the history buffer (e.g., when an antenna port is added to or removed from the history buffer).

[0103] While the examples provided herein are described with respect to a wireless device determining a reservation applicable to a plurality of antenna ports to facilitate understanding, aspects of the disclosure can also apply to any other antenna classification, such as an antenna group. For example, a wireless device can determine a reservation associated with an antenna group, where the reservation can satisfy transmission attributes (e.g., P limit and P CMAXAn antenna group can include one or more sets of antenna ports, antennas, antenna modules, and / or antenna arrays.

[0104] Aspects of the present disclosure can be applied to any of a variety of wireless communication devices (wireless devices) that can transmit RF signals that result in exposure to human tissue, such as base stations and / or CPEs, to perform RF exposure compliance as described herein.

[0105] Example communication device

[0106] Figure 7 Aspects of an example communication device 700 are illustrated. In some aspects, the communication device 700 is a wireless communication device, such as the first wireless device 102 described above with reference to Figure 1 and 2 the first wireless device 102 described above with reference to

[0107] The communication device 700 includes a processing system 702 coupled to a transceiver 708 (e.g., a transmitter and / or a receiver). The transceiver 708 is configured to transmit and receive signals for the communication device 700 via an antenna 710, such as the various signals as described herein. The processing system 702 can be configured to perform processing functions for the communication device 700, including processing signals received by and / or to be transmitted by the communication device 700.

[0108] The processing system 702 can include one or more processors 720. In aspects, the one or more processors 720 can represent any of the processors 210 and / or modems 212 as described with reference to Figure 2 the first wireless device 102 described above with reference to Figure 6 the first wireless device 102 described above with reference to

[0109] In the depicted example, the computer-readable medium / memory 730 stores code 731 (e.g., executable instructions) for obtaining, code 732 for determining, code 733 for transmitting, code 734 for tracking, or any combination thereof. Processing of the code 731-734 can cause the communication device 700 to perform the operations 600 described with reference to Figure 6 the first wireless device 102 described above with reference to

[0110] One or more processors 720 include circuitry configured to implement (e.g., execute) code stored in computer-readable medium / memory 730, including circuitry 721 for acquisition, circuitry 722 for determination, circuitry 723 for transmission, circuitry 724 for tracking, or any combination thereof. Processing using circuitry 721-724 can enable communication device 700 to perform actions related to… Figure 6 The operation described is 600 or any aspect related to the operation described herein.

[0111] The various components of the communication device 700 can provide for performing tasks related to... Figure 6 The described operation 600 or any aspect of the operation described herein. For example, a unit for sending, transmitting, or outputting for transmission may include... Figure 2 The TX path 214 and / or antenna 218 of the first wireless device 102 shown are illustrated. Figure 7 The communication device 700 includes a transceiver 708 and an antenna 710. The unit for receiving or acquiring data may include... Figure 2 The first wireless device shown has an RX path 216 and / or antenna 218 and / or Figure 7 The communication device 700 includes a transceiver 708 and an antenna 710. Units for acquisition, determination, and / or tracking may include processors, such as... Figure 2 The processor 210 and / or modem 212 and / or described in the text Figure 7 The processor is 720.

[0112] Example

[0113] Examples of implementation methods are described in the following numbered clauses:

[0114] Aspect 1: A method for wireless communication by a wireless device, comprising: obtaining information associated with a plurality of antenna ports; determining one or more reservations based at least in part on the information; and transmitting a first signal via a first antenna port at a first transmit power determined at least in part on the one or more reservations, while maintaining at least a portion of the one or more reservations for future transmission via a second antenna port.

[0115] Aspect 2: According to the method of aspect 1, wherein, for each of the plurality of antenna ports, the information includes an indication of the difference between the maximum transmit power and the maximum time-averaged transmit power.

[0116] Aspect 3: The method according to aspect 1 or 2, wherein, for each of the plurality of antenna ports, the information includes an indication of the relationship between the maximum transmit power and the maximum time-averaged transmit power.

[0117] Aspect 4: The method of any of aspects 1-3, wherein, for each of the plurality of antenna ports, the information comprises an indication of the one or more reservations to be used for the respective antenna port.

[0118] Aspect 5: The method of any of aspects 1-4, wherein, for each of the plurality of antenna ports, the information comprises: an identifier associated with the respective antenna port; a maximum time-averaged transmit power associated with the respective antenna port; a target transmit power; an indication of when the respective antenna port was last used for transmission; a duration of a time-averaging time window associated with the respective antenna port; or a combination thereof.

[0119] Aspect 6: The method of any of aspects 1-5, wherein determining the one or more reservations comprises: determining a maximum value of power differences associated with the plurality of antenna ports; and determining the one or more reservations based on the maximum value associated with the respective antenna port.

[0120] Aspect 7: The method of any of aspects 1-6, wherein obtaining the information comprises: tracking the information as a history buffer associated with the plurality of antenna ports.

[0121] Aspect 8: The method of any of aspects 1-7, wherein the plurality of antenna ports is a set of antenna ports that have participated in transmission over a time period.

[0122] Aspect 9: The method of aspect 8, wherein the time period is based on a time-averaging time window associated with a radio frequency (RF) exposure limit.

[0123] Aspect 10: The method of any of aspects 1-9, wherein the plurality of antenna ports is a set of antenna ports that are active at a time of determining the one or more reservations.

[0124] Aspect 11: The method of aspect 10, wherein an antenna port is considered active if the antenna port will participate in transmission in a particular time interval.

[0125] Aspect 12: The method of any of aspects 1-11, wherein the plurality of antenna ports is a set of antenna ports that have been active during a time the wireless device has been operable.

[0126] Aspect 13: The method of aspect 12, wherein the time the wireless device has been operable corresponds to a time the wireless device has been powered on.

[0127] Aspect 14: The method of any of aspects 1-13, wherein the plurality of antenna ports comprises all antenna ports of the wireless device.

[0128] Aspect 15: The method of any of aspects 1-14, further comprising: determining the first transmit power that would comply with an RF exposure limit while maintaining the one or more reservations for the future transmission; and updating the one or more reservations in response to one or more criteria being met.

[0129] Aspect 16: The method of any of aspects 1-15, further comprising: transmitting a second signal via the second antenna port at a second transmit power that uses the at least a portion of the one or more reservations.

[0130] Aspect 17: The method of any of aspects 1-16, wherein the one or more reservations are associated with a particular type of transmission.

[0131] Aspect 18: The method of aspect 17, wherein the particular type of transmission comprises a transmission associated with a high priority service relative to a plurality of priorities.

[0132] Aspect 19: The method of aspect 17 or 18, wherein the particular type of transmission comprises: voice traffic; video traffic; gaming traffic; video conferencing traffic; over-the-top communication (OTTC) traffic; control signaling; hybrid automatic repeat request (HARQ) feedback; or any combination thereof.

[0133] Aspect 20: An apparatus for wireless communication, comprising: a memory; and a processor coupled to the memory, the processor configured to: obtain information associated with a plurality of antenna ports; determine one or more reservations based at least in part on the information; and control transmission of a first signal via a first antenna port at a first transmit power determined based at least in part on the one or more reservations while maintaining at least a portion of the one or more reservations for a future transmission via a second antenna port.

[0134] Aspect 21: The apparatus of aspect 20, further comprising: a transmitter configured to transmit the first signal via the first antenna port, wherein the information comprises, for each antenna port of the plurality of antenna ports, an indication of a difference between a maximum transmit power and a maximum time-averaged transmit power.

[0135] Aspect 22: The apparatus of aspect 20 or 21, wherein, for each antenna port of the plurality of antenna ports, the information comprises an indication of a relationship between a maximum transmit power and a maximum time-averaged transmit power.

[0136] Aspect 23: The apparatus of any of aspects 20-22, wherein, for each of the plurality of antenna ports, the information comprises an indication of the one or more reservations to be used for the respective antenna port.

[0137] Aspect 24: The apparatus of any of aspects 20-23, wherein, for each of the plurality of antenna ports, the information comprises: an identifier associated with the respective antenna port; a maximum time-averaged transmit power associated with the respective antenna port; a target transmit power; an indication of when the respective antenna port was last used for transmission; a duration of a time-averaging time window associated with the respective antenna port; or a combination thereof.

[0138] Aspect 25: The apparatus of any of aspects 20-24, wherein, to determine the one or more reservations, the processor is further configured to: determine a maximum value of power differences associated with the plurality of antenna ports; and determine the one or more reservations based on the maximum value associated with the respective antenna port.

[0139] Aspect 26: The apparatus of any of aspects 20-25, wherein, to obtain the information, the processor is further configured to track the information as a history buffer associated with the plurality of antenna ports.

[0140] Aspect 27: The apparatus of any of aspects 20-26, wherein the processor is further configured to: control transmission of a second signal via the second antenna port using a second transmit power of the at least a portion of the one or more reservations, and update the one or more reservations in response to one or more criteria being satisfied.

[0141] Aspect 28: The apparatus of any of aspects 20-27, wherein the one or more reservations are associated with a particular type of transmission.

[0142] Aspect 29: The apparatus of aspect 28, wherein the particular type of transmission comprises a transmission associated with a high priority service relative to a plurality of priorities.

[0143] Aspect 30: An apparatus for wireless communication, comprising: means for obtaining information associated with a plurality of antenna ports; means for determining one or more reservations based at least in part on the information; and means for transmitting a first signal via a first antenna port with a first transmit power determined based at least in part on the one or more reservations, while maintaining at least a portion of the one or more reservations for future transmissions via a second antenna port.

[0144] Aspect 31 : An apparatus comprising: a memory including computer-executable instructions; and one or more processors configured to execute the computer-executable instructions and cause the apparatus to perform the method of any of aspects 1-19.

[0145] Aspect 32: An apparatus comprising means for performing the method of any of aspects 1-19.

[0146] Aspect 33 : A non-transitory computer-readable medium comprising: executable instructions that, when executed by one or more processors of an apparatus, cause the apparatus to perform the method of any of aspects 1-19.

[0147] Aspect 34: A computer program product, embodied on a computer-readable storage medium, comprising code for performing the method of any of aspects 1-19.

[0148] Additional Notes

[0149] The preceding description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limiting in terms of the scope, applicability, or configurations set forth in the claims. Various modifications can occur to those skilled in the art upon reading the description herein, and such modifications are intended to be within the scope of the claims. For example, changes can be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples can omit, substitute, or add various procedures or components as appropriate. For instance, the methods described can be performed in an order different from that described, and various steps can be added, omitted, or combined. Also, features described with respect to some examples can be combined in some other examples. For example, an apparatus can be implemented or a method can be practiced using any number of the aspects described herein. In addition, the scope of the disclosure is intended to cover devices, apparatus, methods and articles of manufacture that fall within the generic scope of the various aspects described herein. It will be understood by those within the art that, in general, terms used herein, and especially

[0150] The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein can be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an ASIC, a Field Programmable Gate Array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor can be a microprocessor, but in the alternative, the processor can be any commercially available processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a

[0151] As used herein, a phrase referring to "at least one of a list of items means "any single one of these items or combination of items, including single members. For example, "at least one of: a, b, or c" is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination of multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

[0152] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, "determining" can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, "determining" can include resolving, selecting, choosing, establishing, and the like.

[0153] The methods disclosed herein comprise one or more actions for implementing the methods. The actions of the methods can be interchanged with one another without departing from the scope of the claims. That is, unless a specific order of actions is specified, the order and / or use of specific actions can be modified without departing from the scope of the claims. Further, various operations of the methods described above can be performed by any suitable means capable of performing the corresponding functions. The means can include various hardware and / or software component(s) and / or module(s), including, but not limited to a circuit, an application specific integrated circuit (ASIC), or processor. For example, a processor can execute a program to effect the functions of the means.

[0154] The following claims are not intended to be limited to the aspects shown herein but are to be accorded the full scope consistent with the language claims. In the claims, means-plus-function clauses, if any, are intended to cover the elements as set forth in the specification, including any future equivalents of such elements as specified in 35 U.S.C. § 112(f). Other implementations are within the scope of the following claims. Nothing in the specification is to be construed as indicating any element as essential or indispensable to the practice. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to mean including, but not limited to. The word "comprising" is used herein to

Claims

1. A method of wireless communication by a wireless device, comprising: obtaining information associated with a plurality of antenna ports; determining one or more reservations based at least in part on the information; and transmitting a first signal via a first antenna port at a first transmit power determined based at least in part on the one or more reservations while maintaining at least a portion of the one or more reservations for a future transmission via a second antenna port. the information comprises, for each antenna port of the plurality of antenna ports, an indication of a difference between a maximum transmit power and a maximum time-averaged transmit power.

2. The method of claim 1, wherein, the information comprises, for each antenna port of the plurality of antenna ports, an indication of a relationship between a maximum transmit power and a maximum time-averaged transmit power.

3. The method of claim 1, wherein, the information comprises, for each antenna port of the plurality of antenna ports, an indication of the one or more reservations to be used for the respective antenna port.

4. The method of claim 1, wherein, the information comprises, for each antenna port of the plurality of antenna ports:

5. The method of claim 1, wherein, an identifier associated with the respective antenna port; a maximum time-averaged transmit power associated with the respective antenna port; a target transmit power; an indication of when the respective antenna port was last used for transmission; a duration of a time-averaging time window associated with the respective antenna port; or a combination thereof. determining the one or more reservations comprises:

6. The method of claim 1, wherein, determining a maximum value of power differences associated with the plurality of antenna ports; and determining the one or more reservations based on the maximum value associated with the respective antenna port. obtaining the information comprises tracking the information as a history buffer associated with the plurality of antenna ports.

7. The method of claim 1, wherein, the plurality of antenna ports is a set of antenna ports that have participated in transmission in a time period.

8. The method of claim 1, wherein, the time period is based on a time-averaging time window associated with a radio frequency (RF) exposure limit.

9. The method of claim 8, wherein, the plurality of antenna ports is a set of antenna ports that are active at a time of determining the one or more reservations.

10. The method of claim 1, wherein, an antenna port is considered active if the antenna port will participate in transmission in a particular time interval.

11. The method of claim 10, wherein, the plurality of antenna ports is a set of antenna ports that have been active during a time the wireless device has been operable.

12. The method of claim 1, wherein, the time the wireless device has been operable corresponds to a time the wireless device has been powered on.

13. The method of claim 12, wherein, the plurality of antenna ports comprises all antenna ports of the wireless device.

14. The method of claim 1, wherein, 15. The method of claim 1, further comprising: determining that the first transmit power will comply with an RF exposure limit while maintaining the one or more reservations for the future transmission.

16. The method of claim 1, further comprising: transmitting a second signal via the second antenna port at a second transmit power that uses the at least a portion of the one or more reservations; and updating the one or more reservations in response to one or more criteria being satisfied. the one or more reservations are associated with a particular type of transmission. the particular type of transmission comprises a transmission associated with a high priority service relative to a plurality of priorities.

17. The method of claim 1, wherein, the particular type of transmission comprises:

18. The method of claim 17, wherein, voice traffic; 19. The method of claim 17, wherein, video traffic; game traffic; video conference traffic; ​ ​ Over-the-top communication (OTTC) traffic; Control signaling; Hybrid automatic repeat request (HARQ) feedback; or Any combination thereof.

20. An apparatus for wireless communication, comprising: a memory; and a processor coupled with the memory, the processor configured to: obtain information associated with a plurality of antenna ports; determine one or more reservations based at least in part on the information; and control transmission of a first signal via a first antenna port at a first transmit power determined based at least in part on the one or more reservations while maintaining at least a portion of the one or more reservations for future transmission via a second antenna port.

21. The apparatus of claim 20, further comprising: a transmitter configured to transmit the first signal via the first antenna port, wherein the information comprises, for each antenna port of the plurality of antenna ports, an indication of a difference between a maximum transmit power and a maximum time-averaged transmit power.

22. The apparatus of claim 20, wherein, for each antenna port of the plurality of antenna ports, the information comprises an indication of a relationship between a maximum transmit power and a maximum time-averaged transmit power.

23. The apparatus of claim 20, wherein, for each antenna port of the plurality of antenna ports, the information comprises an indication of the one or more reservations to be used for the respective antenna port.

24. The apparatus of claim 20, wherein, for each antenna port of the plurality of antenna ports, the information comprises: an identifier associated with the respective antenna port; a maximum time-averaged transmit power associated with the respective antenna port; a target transmit power; an indication of when the respective antenna port was last used for transmission; a duration of a time-averaging time window associated with the respective antenna port; or a combination thereof.

25. The apparatus of claim 20, wherein, to determine the one or more reservations, the processor is further configured to: determine a maximum value of power differences associated with the plurality of antenna ports; and determine the one or more reservations based on the maximum value associated with the respective antenna port.

26. The apparatus of claim 20, wherein, to obtain the information, the processor is further configured to track the information as a history buffer associated with the plurality of antenna ports.

27. The apparatus of claim 20, wherein, the processor is further configured to: control transmission of a second signal via the second antenna port at a second transmit power using the at least a portion of the one or more reservations, and update the one or more reservations in response to one or more criteria being satisfied.

28. The apparatus of claim 20, wherein, the one or more reservations are associated with a particular type of transmission.

29. The apparatus of claim 28, wherein, the particular type of transmission comprises transmission associated with a high priority service relative to a plurality of priorities.

30. An apparatus for wireless communication, comprising: means for obtaining information associated with a plurality of antenna ports; means for determining one or more reservations based at least in part on the information; and means for transmitting a first signal via a first antenna port at a first transmit power determined based at least in part on the one or more reservations while maintaining at least a portion of the one or more reservations for future transmission via a second antenna port.

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