Methods for controlling the availability of an ambient IoT device communication

Abstract

In accordance with implementations, a communication device receives a first message from a reader device. After receiving the first message, the communication device selects a response message from an expected response message and a negative acknowledgement message in accordance with a comparison of an energy threshold and an amount of energy stored at the communication device. The expected response message is selected in accordance with the comparison indicating that the amount of energy stored at the communication device is sufficient to transmit the expected response message. The negative acknowledgement message is selected in accordance with the comparison indicating that the amount of energy stored at the communication device is insufficient to transmit the expected response message. The communication device transmits to the reader device a device-to-reader (D2R) transmission that comprises the response message and at least one indicator of one or more energy-related conditions of the communication device.

Description

METHODS FOR CONTROLLING THE AVAILABILITY OF AN AMBIENT IOT DEVICE COMMUNICATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This patent application claims priority to U.S. Provisional Application No. 63 / 703,055, filed on October 3, 2024, and entitled “Methods for Controlling the Availability of an Ambient IOT Device Communication,” which is hereby incorporated by reference herein as if reproduced in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates generally to wireless communications, and, in particular embodiments, to methods and apparatus for controlling the availability of an ambient Internet of things (A-IoT) device for communication.BACKGROUND

[0003] loT devices are communication devices that operate on energy harvested from an ambient energy source such as electromagnetic waves (e.g., radio waves, RF waves), light, thermal differential, kinetic energy, v ibration, etc., depending on the device capability. A-IoT devices may also be referred to as tags, batten -less devices, zero-power devices, etc. For these types of devices, when the energy harvested and stored at the device becomes insufficient to sustain its operations for communicating with a reader device, the device becomes unavailable to communicate with the reader device and enters a mode of operation where the device may harvest energy as it can until its energy becomes sufficient for resuming its normal operations. Herein and hereafter, the word “reader” refers to the reader device and the word “device” generally refers to the A-IoT device unless specified otherwise.

[0004] A device’s availability for communications with the reader may be limited by how the device harvests its energy. For example, the availability of a solar-powered device for communications may be limited to the duration of daylight, and in addition, the rate of energy harvesting may be slower on cloudy days. Even for a device that harvests energy from radio waves, the duration of its unavailability for communications due to energy harvesting can be up to several tens of seconds. When its stored energy is above a turn-on threshold, a device can start performing various tasks such as monitoring for reader-to-device (R2D) signals for a trigger message / event and making device-to-reader (D2R) transmission(s) after being triggered. Performing these tasks depletes energy storage (e.g., capacitor) until a turn-off threshold is reached, forcing the device to stop performing some of the various tasks and allowing energy storage to be recharged by energy harv esting. When a device has too little energy, it may risk losing theFW 6000735PCT02 -1-context of its access-stratum (AS) configuration and non-access-stratum (NAS) configuration if the device does not have non-volatile memory (NVM), such as electrically erasable programmable read-only memory (EEPROM), or losing at least the context of its AS configuration if the device has NVM while the context of its NAS configuration, such as security keys and assigned NAS layer temporary identifier (ID), maybe stored in the NVM. However, operations using (e.g., writing information into and reading information from) NVM can be energy intensive, and NVM may have a limited life cycle. On the other hand, w ithout NVM, restoring network configuration after the device regains sufficient energy, especially restoring the NAS configurations and performing authentication and authorization procedure as a prerequisite, requires many transmissions, time, and energy.

[0005] Therefore, minimizing energy consumption at the device and controlling its availability to communicate w ith the reader is important. However, due to the low-power and low-cost nature of such devices, a clock running within the device is generally inaccurate and has severe drifting issues, especially if reference clock signals are not frequently transmitted to correct clock timing at the device. Conventional power-saving techniques, such as discontinuous reception (DRX), which may be based on (pre- )configured patterns of ON and OFF periods derived from a running clock may be inadequate in an A-IoT communication system.SUMMARY

[0006] Technical advantages are generally achieved, by implementations of this disclosure which describe methods, apparatus, and system.

[0007] In accordance with implementations, a communication device receives a first message from a reader device. After receiving the first message, the communication device selects a response message from an expected response message and a negative acknowledgement message in accordance with a comparison of an energy threshold and an amount of energy stored at the communication device. The expected response message is selected in accordance with the comparison indicating that the amount of energy stored at the communication device is sufficient to transmit the expected response message. The negative acknowledgement message is selected in accordance with the comparison indicating that the amount of energy7stored at the communication device is insufficient to transmit the expected response message. The communication device transmits to the reader device a device-to-reader (D2R) transmission that comprises the response message and at least one indicator of one or more energy-related conditions of the communication device.FW 6000735PCT02 -2-

[0008] In some implementations, the at least one indicator of the one or more energy-related conditions may comprise a first indicator indicating an energy trend of the communication device. The first indicator may be set to a first value in accordance with an increase in the amount of energy stored at the communication device. The first value indicates the increase in the amount of energy stored at the communication device. The first indicator may be set to a second value in accordance w ith a decrease in the amount of energy stored at the communication device. The second value indicating the decrease in the amount of energy stored at the communication device.

[0009] In some implementations, the at least one indicator may comprise a second indicator indicating an energy-harvesting condition of the communication device. The second indicator may be set to a third value in accordance with the communication device being able to harvest sufficient energy. The third value indicates that the communication device is able to harvest sufficient energy. The second indicator may be set to a fourth value in accordance with the communication device being unable to harvest sufficient energy. The fourth value indicates that the communication device is unable to harvest sufficient energy.

[0010] In some implementations, the at least one indicator may comprise a third indicator indicating an availability of the communication device for communications with the reader device after the D2R transmission is sent. The availability may be set to be available in accordance with the amount of energy stored at the communication device being greater than or equal to a second energy threshold. The availability may be set to be unavailable in accordance with the amount of energy stored at the communication device being less than the second energy threshold.

[0011] In some implementations, the third indicator may be set to a fifth value indicating that the communication device remains in an ON state after the D2R transmission is sent. In some implementations, the third indicator may be set to a sixth value indicating that the communication device is in an OFF state or a SLEEP state after the D2R transmission is sent.

[0012] In some implementations, the communication device may be configured with time windows for monitoring for the first message. A configuration for the time windows may comprise a duration for the monitoring within each of the time windows and a periodicity of the time windows. The at least one indicator of the one or more energy- related conditions may comprise a fourth indicator indicating a number of time windows that the communication device will be unavailable for communications with the reader device.FW 6000735PCT02 -3-

[0013] In some implementations, the duration and the periodicity may be measured as respective numbers of a specific R2D signal received.

[0014] In some implementations, the at least one indicator of the one or more energy-related conditions may comprise a fifth indicator indicating an estimate of a remaining energy of the communication device.

[0015] In some implementations, the first message may comprise a paging message.

[0016] In some implementations, the energy threshold may be a second amount of energy for the transmission of the expected response message.

[0017] In accordance with implementations, a reader device transmits a first message to a communication device. In response to transmitting the first message, the reader device receives a device-to-reader (D2R) transmission that comprises a response message and at least one indicator of one or more energy-related conditions of the communication device after the communication device sends the D2R transmission. A length of the response message is a first length of an expected response message or a second length of a negative acknowledgement message. The first length of the expected response message is greater than the second length of the negative acknowledgement message. The first length of the expected response message is indicated in the first message. The expected response message is received in accordance with the communication device having energy to transmit the response message of the first length. The negative acknowledgement message is received in accordance with the communication device having insufficient energy to transmit the response message of the first length. The reader device schedules a reader-to-device (R2D) transmission in accordance with an availability of the communication device to receive the reader-to- device (R2D) transmission based on the at least one indicator of the one or more energy- related conditions and the response message.

[0018] In some implementations, the at least one indicator of the one or more energy-related conditions may indicate an energy trend of the communication device or an energy-harvesting condition of the communication device.

[0019] In some implementations, the at least one indicator of the one or more energy-related conditions of the communication device may indicate that the communication device is available for communications with the reader device. The at least one indicator may be set to a first value to indicate that the communication device has sufficient energy for another D2R transmission.FW 6000735PCT02 -4-

[0020] In some implementations, the at least one indicator of the one or more energy-related conditions of the communication device may indicate that the communication device is unavailable for communications w ith the reader device. The at least one indicator may be set to a second value to indicate that the communication device has insufficient energy for another D2R transmission.

[0021] In some implementations, the reader device may schedule the R2D transmission by determining an estimated remaining energy of the communication device based on the at least one indicator of the one or more energy- related conditions and one or more other attributes associated with the communication device.

[0022] In some implementations, the reader device may transmit the R2D transmission to the communication device.

[0023] In some implementations, the reader device may anticipate another D2R transmission from the communication device within a time window. The another D2R transmission may comprise another expected message or another negative acknowledgement. The another D2R transmission may further comprise a second indicator of a second one or more energy-related conditions of the communication device. The reader device may adjust the estimated remaining energy of the communication device in accordance with receiving the another D2R transmission or an absence of receiving the another D2R transmission in the time window.

[0024] In some implementations, the one or more other attributes associated wdth the communication device may comprise one or more of a duration of the D2R transmission of the communication device, one or more respective durations of one or more past D2R transmissions of the communication device, an operational state of the communication device, a task being performed by the communication device, a location of the communication device, a distance between the communication device and the reader device, energy harvested by the communication device over a past time period, or a time of day.

[0025] In some implementations, the reader device may send the R2D transmission to the communication device. The reader device may determine whether the R2D transmission w as successful. The reader device may adjust one or more parameters of a machine learning model, based on whether the R2D transmission was successful.

[0026] In some implementations, the first message may comprise a paging message.FW 6000735PCT02 -5-BRIEF DESCRIPTION OF THE DRAWINGS

[0027] For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:[00281 FIG. 1 illustrates an example of a communication system involving a network and communication devices that access the network via a reader device, in accordance with some implementations;

[0029] FIGs. 2A-2E illustrate examples of different network topologies that can be used to implement communications network that includes a reader device and a communication device of the present disclosure, in accordance with some implementations;

[0030] FIG. 3 illustrates an example of a flowchart of operations performed, by a reader device, to schedule transmission of a reader-to-device (R2D) message to a communication device, in accordance with some implementations;

[0031] FIG. 4 illustrates a block diagram of an example of a system 400 for using a reader device to estimate the remaining energy of a communication device or its operational state, in accordance with some implementations;

[0032] FIG. 5 illustrates an example of a flowchart of operations performed, by a communication device, to indicate one or more energy-related conditions and / or availability to a reader, in accordance with some implementations;

[0033] FIG. 6 illustrates an example of a process performed, by a communication device, to determine whether the communication device has sufficient energy to complete a messaging sequence, in accordance with some implementations;

[0034] FIG. 7 illustrates an example state machine and associated state transitions of a communication device, in accordance with some implementations;

[0035] FIG. 8 illustrates an example of a flowchart of a process performed, by a communication device, as the communication devices changes its operational state, in accordance w ith some implementations;

[0036] FIG. 9A illustrates an example flow diagram of an example of communications between a reader device and a communication device, in accordance with some implementations;

[0037] FIG. 9B illustrates an example flow diagram of another example of communications between a reader device and a communication device, in accordance with some implementations;FW 6000735PCT02 -6-

[0038] FIG. 10 A illustrates an example flow diagram of another example of communication between a reader device and a communication device that includes sending of a device-to-reader (D2R) transmission sent via PDRCH that includes an energy status indicator (ESI), in accordance with some implementations;

[0039] FIG. 10B illustrates an example of a D2R transmission that includes an ESI, in accordance with some implementations;

[0040] FIG. 11 illustrates an example of another flowchart of operations performed, by a communication device, to indicate one or more energy-related conditions or availability to a reader, in accordance with some implementations;

[0041] FIG. 12 illustrates an example of another flowchart of operations performed, by a reader device, to schedule transmission of a reader-to-device (R2D) message, in accordance with some implementations;

[0042] FIG. 13 illustrates an example of a communications system, in accordance with some implementations;

[0043] FIG. 14 illustrates another example of a communications system, in accordance with some implementations;

[0044] FIGs. 15A and 15B illustrate example devices that may implement the methods and teachings according to this disclosure, in accordance with some implementations; and

[0045] FIG. 16 illustrates an example of a computing system that may be used for implementing the devices and methods described herein, in accordance with some implementations.

[0046] Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.DETAILED DESCRIPTIONS

[0047] The present disclosure relates to providing methods and systems for a communication device to determine and communicate one or more energy-related conditions of the communication device to a reader device in a device-to-reader (D2R) transmission. Energy-related conditions of the communication device can include, for example, one or more of an operational state of a communication device, an energyharvesting condition of a communication device, an energy status indicator (ESI) indicating whether a communication device will remain available for communicationFW 6000735PCT02 -7-wit h a reader device or not after a current D2R transmission, an energy trend of a communication device, a number of time windows pre-configured for the communication device to communicate with a reader device but later determined by the communication device that it will be unable to communicate with the reader device, or a quantized energy’ level of the energy stored at the communication device. The one or more energy-related conditions of the communication device that are communicated to the reader enable the reader to schedule reader-to-device (R2D) transmissions during periods when the communication device is expected to be available. Other advantages of the present disclosure include, for example, a communication device being available for longer periods of time while minimizing frequency of memory’ is erased.

[0048] The one or more energy- related conditions communicated by7the communication device to the reader device may assist the reader in tracking device availability^ such as, for example, a state of the communication device, whether the communication device is available for communication with the reader device, estimating an energy" status of the communication device, and in scheduling R2D transmissions or continuous wave (CW) transmissions, which may provide energy that is harvestable to the device if the device is capable of harvesting energy" from radio waves. Then, based on the availability’ of the communication device determined by the reader device, the reader device can predict (anticipate) which state that the communication device will be in at a specific time in the future when a need for communicating with the communication device arises.

[0049] FIG. 1 illustrates an example of a communication system too involving a network 140 and communication devices 110a, nob that access the network 140 via respective reader devices 120a, 120b. A reader device 120a, 120b is any device within the communication system too that performs the operations or functions of a reader, as described herein. By way of example, and as shown in FIG. 1, the reader function may be implemented in a next generation Node B (gNB), as show n by reader device 120b, or in an intermediate user equipment (UE), as shown by reader device 120a, which is served by a gNB 130 that supports A-IoT. The reader device 120a may be referred to, herein, as an intermediate UE, a reader UE, an A-IoT relay UE, or a reader device. Messages sent from a reader device 120a, 120b to a communication device 110a, 110b are sent via a physical reader to device channel (PRDCH). Responses sent from the communication device 110a, 110b to a reader device 120a, 120b use a physical device to reader channel (PDRCH). The CW, on which the device backscatters its information bits, may be provisioned by the reader device 120a, 120b or by a CW node outside the topology of the network too. Some communication devices 110a, 110b, such as active devices, may notFW 6000735PCT02 -8-use backscattering or may not need a CW node. An active device may generate its own carrier for transmission.

[0050] A communication device noa, nob is any device within the communication system too that performs the operations of a communication device, as described herein. By way of example, and as shown in FIG. 1, a communication device lioa, 110b can include an A-IoT device such as a radio-frequency identification (RFID) tag. Such A-IoT devices may also be known as tags, battery-less devices, zero-power device, etc. For these types of communication devices lioa, nob, when the energy harvested and stored at the communication device noa, nob becomes insufficient to sustain its operations for communicating with a reader device 120a, 120b, the communication device noa, nob becomes unavailable to communicate with the reader device 120a, 120b and enters a mode of operation where the communication device noa, nob may harvest energy until its energy level becomes sufficient for resuming its normal operations. The communication device noa, nob may be referred to herein as an A-IoT device, communication device, or simply a “device.”

[0051] Each communication device noa, nob is capable of harvesting energy in a number of different ways. In some implementations, for example, the communication device noa, 110b may be capable of harvesting energy from electromagnetic waves such as, for example, radio waves. However, the communication device noa, nob is not limited to harvesting energy from such sources. For example, in some implementations, the communication device noa, nob can have the capability of harvesting energy from one or more ambient energy sources such as, for example, light, heat, or vibration. In some implementations, the communication device noa, nob can be configured to convey to the reader device 120a, mob a need for more (or for less) energy such as, for example, light, heat, or vibration, generated by a specific energy source. In some implementations, the communication device noa, nob can unilaterally determine to transition from a first state (e.g., ON or OFF) to a second state (e.g., OFF or ON), which may be referred to as device-driven state transitioning. In other implementations, the reader device 120a, 120b can provide information in a communication, to the communication device noa, nob, that causes the communication device noa, nob to transition from a first state to a second state, which may be referred to as reader-driven state transitioning. In yet other implementations, a combination of the reader-driven state transitioning and the device-driven state transition can be supported.

[0052] The communication device noa, nob can, at any particular time, be in one of three different operating states that include, for example, an ON state, an OFF state, and a SLEEP state. The reader device 120a, 120b may consider the communication deviceFW 6000735PCT02 -9-noa, nob as being available for communications when the communication device 110a, nob is in (or is estimated by the reader as being in) the ON state. Likewise, the reader device 120a, 120b may consider the communication device noa, nob as being unavailable for communications when the communication device noa, nob is in (or is estimated by the reader as being in) the SLEEP state or the OFF state.

[0053] The reader device 120a, 120b can estimate the availability of a communication device noa, nob for communications based on one or more energy-related conditions received from the device. Then, the reader device 120a, 120b can schedule, based on the one or more received energy-related conditions, one or more R2D transmission (s) to be sent to the device, solicit one or more D2R transmission(s) from the device, or both. In some implementations, the reader device 120a, 120b may change filtering criteria in one or more subsequent A-IoT paging messages based on the availabilities of a communication device 110a, 110b as one or more energy-related conditions are received from a communication device 110a, 110b or as one or more energy-related conditions of communication devices 110a, 110b are estimated by the reader device 120a, 120b.

[0054] In some implementations, a reader device 120b may communicate with a core network 140 of the communication system too directly such as, for example, when the operations of a reader function are implemented in a gNB such as in, for example, reader device 120b. In other implementations, a reader device 120a may communicate indirectly with the core network 140 of the communication system too such as, for example, when the operations of a reader function are implemented in a UE such as in, for example, reader device 120a. A core network 140 of the communication system too can include, for example, an access and mobility management function (AMF) 142, a network exposure function (NEF) 144, a user plane function (UPF) 146, and a data network (DN) 148.

[0055] FIG. 2A-2E illustrate examples of different network topologies 200A, 200B, 200C, 200D, 200E that can be used to implement communications network that includes a reader device 120 and a communication device 110 of the present disclosure. In some implementations, a reader device 120 can be implemented in a base station 230 and communicate with a communication device such as ambient loT device 210 using ambient loT data / signaling 250, as illustrated by the network topology 200A of FI G. 2A. In other implementations, a reader device 120 can be implemented in an intermediate node 220 such as a UE that that is configured to communicate with the base station 230 using a cellular link 260 and a communication device such as ambient loT device 210 using ambient loT data / signaling 250, as illustrated by the network topology 200B of FIG. 2B.FW 6000735PCT02 -10-

[0056] In other implementations, the reader 210 can be implemented in an assisting node 270 that provides downlink assistance as shown in the network topology 200C of FIG. 2C or in an assisting node 270 that provides uplink assistances as shown in the network topology of 200D of FIG. 2D. For example, as illustrated by the network topology 200C of FIG. 2C, the reader 120 can be implemented in assisting node 270 that provides downlink assistance via a cellular link 260. In this implementation, a communication device such as ambient loT device 210 is configured to send uplink communications to the base station 230 and receive downlink communications from the base station 230 that are communicated using the cellular link 260 and routed through the assisting node 270 to the ambient loT device 210 using ambient loT data / signaling 250. In another implementation, as illustrated by the network topology 200D of FIG. 2D, the reader 120 can be implemented in assisting node 270 that provides uplink assistance via a cellular link 260. In this implementation, a communication device such as ambient loT device 210 is configured to receive downlink communications from the base station 230. In addition, the ambient loT device 210 can send uplink communications to the base station 230 that are routed to the assisting node 270 using ambient loT data / signaling 250 and then communicated, by the assisting node 270, to the base station 230 using a cellular link 260.

[0057] In yet another implementation, a reader device 120 can be implemented in a UE 220 and communicate with a communication device such as ambient loT device 210 using ambient loT data / signaling 250, as illustrated by the network topology 200E of FIG. 2E.

[0058] FIG. 3 illustrates an example of a flowchart of a process 300 performed, by a reader device to schedule transmission of a reader-to-device (R2D) message to a communication device. An example of the process 300 will be described below as being performed by a reader device such as the reader device 120a, 120b of the communication network too to communicate with a communication device such as the communication device 110a, 110b of FIG. 1.

[0059] Execution of the process 300, by a reader device, begins with the reader device sending a first R2D transmission to solicit a first response from a communication device (operation 310). In some implementations, the first R2D transmission may be sent, by the reader device, in response to a first A-IoT service request from an A-IoT core network (CN). The first A-IoT service request from the A-IoT CN may, for example, include a request that solicits the first response from the communication device.FW 6000735PCT02 -11-

[0060] Execution of the process 300, by the reader, continues with the reader device receiving a first D2R transmission, from the communication device, that includes information indicating one or more energy-related conditions at the communication device (operation 320). In some implementations, the D2R transmission may also include the first response requested by the A-IoT service.

[0061] The information received in operation 320 may include, for example, an energy status indication (ESI) indicating whether the communication device will have sufficient energy left for making another D2R transmission, in operation 320. In some implementations, the ESI can include, for example, a first value (e.g., value 0) indicating that the communication device will have insufficient energy left or a second value (e.g., value 1) indicating that the communication device will have sufficient energy left. Alternatively, the ESI may (explicitly or implicitly) indicate whether the communication device will stay in the ON state or will make a state transition from the ON state to the SLEEP state (or the OFF state) after making the D2R transmission that was received, by the reader device, in operation 320. In such an implementation, the ESI can include a first value (e.g., value 0) indicating that the communication device wall make the state transition from the ON state to the SLEEP state (or the OFF state) after making the D2R transmission that was received in operation 320 or a second value (e.g., value 1) of the ESI indicating that the communication device will stay in the ON state after making the D2R transmission received in operation 320.

[0062] In yet another alternative, the ESI may (explicitly or implicitly) indicate whether the communication device will still be available for communication with the reader after making the D2R transmission that is received in operation 320. In such implementations, the ESI can include a first value (e.g., value o) indicating that the communication dev ice will not be available (e.g., will be unavailable) or a second value (e.g., value 1) of the ESI indicating that the communication dev ice will still be available. As previously described, being in the ON state, being available for communication, and having sufficient energy left for making another D2R transmission generally have the same meaning and these phrases may be used interchangeably. Likewise, the communication device being in the SLEEP state or the OFF state, being unavailable for communication, and having insufficient energy left for making another D2R transmission generally have the same meaning and these phrases may be used interchangeably.

[0063] In some implementations, the information indicating the one or more energy- related conditions received in operation 320 may include an energy-harvesting condition indication. In some implementations, the energy-harvesting condition indication mayFW 6000735PCT02 -12-indicate whether the communication device is able to harvest energy at a sufficient rate. For example, the energy-harvesting condition indication can include a first value (e.g., value o) indicating that the energy-harvesting condition is bad (or that the communication device is unable to harvest energy at a sufficient rate) or a second value (e.g., value 1) indicating that the energy-harvesting condition is good (or that the communication device is able to harvest energy at a sufficient rate). In some implementations, a measurement taken at an output of an energy- harvesting unit of the communication device may be used for comparing with a specific threshold to determine the energy-harvesting condition indication.

[0064] In some implementations, the information indicating the one or more energy- related conditions may include an energy trend indication indicating. In some implementations, the energy trend indication may indicate whether the energy stored at the communication device is increasing or decreasing. For example, in some implementations, the energy trend indication can include a first value (e.g., value o) indicating that the energy is increasing or a second value (e.g., value 1) indicating that the energy is decreasing. In some implementations, after the D2R transmission, the energy trend may be negative. In some implementations, at least two measurements taken at an energy storage unit of the communication device, one taken at the present time and the other taken at a past time, may be used for comparing with each other to determine the energy trend condition indication.

[0065] In some implementations, the communication device may be pre-configured to operate in a duty-cycle manner, wherein the communication device is configured with a periodicity of the duty cycle and a duration of a time window within each duty cycle for monitoring one or more types of R2D messages, such as the A-IoT paging message, and for sending a response when needed. The communication device is normally expected to be available for communications with the reader device within the time windows. The device may use time outside the time windows for energy-harvesting to sustain its availability for communications with the reader during the pre-configured time windows over a longer time period. However, a situation may arise w here the communication device has drained its energy storage so fast or so deep during a time window that it may be unable to rebuild its energy storage sufficiently to be available for communications with the reader device during one or more subsequent time windows. In this situation, the information indicating the one or more energy-related conditions may include an indication of a number of time windows that the communication device will skip, during which time windows the device is not expected to monitor R2D messages nor respond to the R2D messages. In some implementations, the duration and the periodicity of theFW 6000735PCT02 -13-time windows may be measured in a fixed time unit. In this situation, the communication device may synchronize its clock w ith a clock of the reader device to correct drifting. In some implementations, the duration and periodicity of the time w indow s may be measured as a respective number of specific R2D messages (such as Access Trigger messages) that the communication device receives. In this situation, the communication device and the reader device can operate in an asynchronous manner.

[0066] In some implementations, the information indicating the one or more energy- related conditions may include a quantized energy level of the energy stored at the communication device.

[0067] With these and various other inputs, as described herein w ith respect, for example, FIG. 4 described below, the reader device may keep tracking or estimating the energy level, operational state, and / or availability for communication until a need for communicating w ith the communication device arises.

[0068] Execution of the process 300, by the reader, continues with the reader device determining that there is a need to solicit a second response from the communication device (operation 330). In some implementations, the first A-IoT service request, which had triggered the first R2D transmission sent in operation 310, may also solicit a second response from the communication device. In such implementations, the reader device may determine that there is a need to solicit a second response from the communication device based on first A-IoT service request also soliciting a second response from the communication device. Alternatively, in some implementations, a second A-IoT service request soliciting the second request from the communication device may be received by the reader device. In such alternative implementations, the reader device may determine that there is a need to solicit a second response from the communication device based on the second A-IoT service request.

[0069] Execution of the process 300, by the reader, continues with the reader device estimating which operational state that the communication device is currently in (operation 340). For example, the reader device can estimate, using the operations described with reference to at least FIG. 4 described below, whether the communication device that sent the first D2R transmission received in operation 320 is in an ON state, an OFF state, or a SLEEP state. In response to a determination, by the reader device, that the communication device that sent the first D2R transmission received in operation 320 is estimated to be in an OFF state or a SLEEP state, execution of the process 300, by the reader device, continues at operation 340 by the reader device continues to performFW 6000735PCT02 -14-operations 340 and 350 until the reader determines that the estimated state of the communication device is the ON state in operation 350.

[0070] In response to a determination, by the reader device, at operation 350 that the communication device is estimated to be in an ON state, execution of the process 300, by the reader device, continues at operation 360 with the reader sending a second R2D transmission to solicit the second response from the communication device (operation 360).

[0071] Execution of the process 300, by the reader device, continues with the reader device receiving a second D2R transmission that includes the second response requested by the A-IoT service (operation 370). In some implementations, the second D2R transmission may also include information indicating one or more energy-related conditions at the communication device, e.g., as determined at the time of the second D2R transmission.

[0072] In some implementations, the reader device may track a predetermined amount of time that elapsed from when the second R2D transmission is sent at operation 360. In such implementations, if the reader device does not receive the second response within a specific time limit after sending the second R2D transmission, the reader device may determine that its previous estimation on the operational state of the communication device was incorrect, make an adjustment to one or more models used to estimate an operation state of the communication device, and return to perform operation 340 and continue execution of process 300 until the second response to the second R2D transmission is received with the specific time limit.

[0073] FIG. 4 illustrates a block diagram of an example of a system 400 using a reader device 120a, 120b to estimate the remaining energy of a communication device or its operational state. The system 400 can include an energy estimation model 410 and a scheduler 420. In some implementations, the system 400 can also include a duty cycle configuration engine (not shown in FIG. 4) for configuring the duty cycle configuration 430.

[0074] The energy estimation model 410 is used, by a reader device such as reader device 120a, 120b of FIG. 1, to estimate the remaining energy of a communication device such as communication device 110a, 110b after the communication device sends a D2R transmission. Alternatively, or in addition, the energy estimation model 410 may also determine the operational state of the communication device after the communication device sends the D2R transmission. In some implementations, the energy estimate model 410 may include one or more algorithms, one or more heuristics, one or moreFW 6000735PCT02 -15-probability models, one or more artificial intelligence models, or a combination thereof, that the reader device can apply to information included in a D2R transmission from a communication device, one or more attributes associated w ith the communication device, or a combination thereof, to estimate the remaining energy of a communication device or the operational state of the communication device after the communication device sends the D2R transmission, e.g., periodically or at a time when a need for communicating with the communication device arises.

[0075] As described with reference to the process of FIG. 3 described above, the reader device can receive a D2R transmission that includes information indicating one or more energy-related conditions at the communication device. This information can include, for example, an indication as to whether the communication device has sufficient energy to complete another D2R transmission, an indication of an operational state of the communication device, an indication of an energy trend of the communication device, an indication of the energy-harvesting condition of the communication device, an indication of a number of time windows (or duty cycles) that the device will skip, i.e., be unavailable for communication with the reader device during the number of time windows, w hich were configured for the communication device to monitor, e.g., the A-IoT paging message, an indication of a quantized energy level of the communication device, or a combination thereof.

[0076] The reader device can also access one or more attributes associated with the communication device that sent the received D2R transmission. The one or more attributes associated with the communication device that sent the received D2R transmission include one or more of a duration of the D2R transmission of the communication device, one or more respective durations of one or more past D2R transmissions of the communication device, an operational state of the communication device, a task being performed by the communication device, a location of the communication device, a distance between the communication device and the reader device, energy harvested by the communication device over a past time period, a time of day, or a device type (e.g., transmit power of the device).

[0077] The reader device may provide the information indicating the one or more energy-related conditions at the communication device, the one or more attributes associated with the communication device, or a combination of both, as inputs to the energy estimation model 410. The reader device can use one or more processors to process the provided inputs through the one or more algorithms, the one or more probability models, the one or more artificial intelligence models, or a combination thereof to generate output data corresponding to an estimated remaining energy for theFW 6000735PCT02 -16-communication device, an estimated operational state of the energy device, or a combination of both. Then, the reader device can provide the generated output data as an input to the scheduler 420, and to the duty-cycle configuration unit 430 if the communication device has been pre-configured to operate in the duty-cycle manner, as described above. The duty-cycle configuration unit 430 may, based on the output data, determine whether the communication device needs to be re-configured with a different periodicity and / or a different duration of the time windows to minimize the skipping of time windows, as indicated by the communication device.

[0078] The reader device may use the scheduler 420 to schedule a subsequent R2D transmission to the communication device. In some implementations, the scheduler 420 can receive the output generated by the energy estimation model 410 corresponding to an estimated remaining energy for the communication device, an estimated operational state of the energy device, or both, and then determine an estimated time when the communication device will be in an ON state and able to receive a subsequent R2D transmission. Then, upon a determining, by the reader device, that the estimated time has come, the reader device can send the subsequent R2D transmission to the communication device based on the schedule of one or more R2D transmissions determined by the scheduler 420.

[0079] The reader device may be configured to provide feedback that is used to adjust the energy estimation model 410. The feedback can include an indication that a scheduled R2D transmission was successfully received from the communication device, an indication that a scheduled R2D transmission was not successfully received by the communication device, an indication that a D2R transmission was received in response to a scheduled R2D transmission within a specific time limit, an indication that a D2R transmission was not received in response to a scheduled R2D transmission within a specific time limit, a duration of time between the scheduled R2D transmission to a communication device and a next D2R transmission that was received from the communication device, or a combination thereof.

[0080] Based on this feedback, the reader device can make one or more adjustments to improve its estimations on communication device availability in subsequent estimations. Adjustments can include, for example, storing one or more types of feedback data as an indication of a successful past transmission, storing one or more types of feedback data as an indication of an unsuccessful past transmission, generating a training data item based on the feedback and training a machine learning model using the generated training data item, adjusting a weight or score of one or more parameters of the model based on the feedback data, or any combination thereof.FW 6000735PCT02 -17-

[0081] FIG. 5 illustrates an example of a flowchart of process 500 performed, by a communication device, to indicate one or more energy-related conditions or availability to a reader. An example of the process 500 is described below as being performed by a communication device such as the communication device 110a, 110b of the communication network too to communicate with a reader device such as the reader device 120a, 120b of FIG. 1.

[0082] Execution of the process 500, by a communication device, begins w ith communication device determining one or more energy-related conditions at the communication device (operation 505). For example, the one or more energy-related conditions may include at least one of an operational state, an energy-harvesting condition, or an energy trend of the device. Determining, by the communication device, one or more energy-related conditions at the communication device can include, for example, accessing a most recently determined operational state, energy-harvesting condition, energy related trend, a number of time windows (or duty cycles) to be skipped, or a quantized energy level. In other implementations, the communication device can determine an energy-harvesting condition indicative of how much energy the communication device is currently harvesting, a current energy trend of the device, a number of time windows (or duty cycles) to be skipped, a quantized energy level, or a combination thereof, and determine a to-be-transitioned to operational state. In such instances, the to-be-transitioned to state, the determined energy-harvesting condition, the determined energy trend, the determined number of time windows to be skipped, the quantized energy’ level, or a combination thereof, can be determined during operations 505-

[0083] Execution of the process 500, by the communication device, continues with the communication device determining whether the communication device is being requested to send a response to the reader device (operation 510). In some implementations, the communication device can determine, e.g., based on filtering criteria indicated in a received A-IoT paging message,, that the communication device meets the filtering criteria. In other implementations, a received R2D may include an identifier of a target communication device. That identifier can be used as a filtering criterion by the communication device receiving the message. Then, based on a determination, by the communication device, that the communication device satisfies the filtering criteria, the communication device may determine that it is being requested to send a response to the reader device. In such instances, execution of the process 500, by the communication device, can continue at operations 515. Alternatively, if the communication device determines that the communication device does not satisfy theFW 6000735PCT02 -18-filtering criteria, execution of the process 500, by the communication device, continues to perform operations 505 and 510 until the communication device determines that the communication device is being requested to send a response. In some implementations, the received A-IoT paging message may also include information indicating a type of response is being requested from the communication device.

[0084] In response to determining that it is being requested to send a response, the device further determines whether it has sufficient energy to send the response being requested (operation 515). In some implementations, the communication device can make this determination during operation 515 by comparing the current energy level of the communication device to a first predetermined threshold. In some implementations, the first predetermined threshold can be indicative of a minimum energy level to send a D2R transmission, a minimum energy level for the communication device to stay in an ON state after sending the D2R transmission, or a minimum energy level to send another D2R transmission after sending the D2R transmission with the responses that is being requested.

[0085] In response to determining that the communication device does not have sufficient energy to send the response that is being requested at operation 515, execution of the process 500, by the communication deuce, continues at operation 520 by the communication device sending a first D2R transmission, to the reader device, that includes a first indication indicating that the communication device has insufficient energy to send the response being requested and does not include the response being requested. For example, the length of the D2R transmission including the first indication may be much shorter than (e.g., may be a small fraction of) the length of the D2R transmission containing the requested response. In some implementations, the first indication also indicate (explicitly or implicitly) that the communication device will have insufficient energy left for another D2R transmission after the current (the first) D2R transmission, that the device will transit from the ON state to the SLEEP state (or the OFF state) (or be unavailable) after the current D2R transmission, or a combination of both (operation 520). Then, execution of the process 500, by the communication device, may end.

[0086] Alternatively, in response to determining that the communication device has sufficient energy to send the response that is being requested at operation 515, execution of the process 500, by the communication device, continues at operation 525 with the communication device determining whether, after sending the response being requested, the communication device will have sufficient energy left to stay in the ON state and to make another D2R transmission (e.g., to send another response if being requested)FW 6000735PCT02 -19-(operation 525). In some implementations, the communication device can make this determination during operation 525 by comparing the current energy level of the communication device to a second predetermined threshold. In some implementations, the second predetermined threshold can be indicative of a minimum energy level for the communication device to stay in an ON state after sending the D2R transmission.

[0087] In response to a determination, by the communication device during operation 525, that the communication device does not have sufficient energy left to stay in the ON state and to make a subsequent D2R transmission after sending the response that is being requested, execution of the process 500, by the communication device, can continue w ith the communication device sending a complete D2R transmission to the reader device that includes the full response being requested. In some implementations, this complete D2R transmission includes the response being requested and the first indication indicating (explicitly or implicitly) the communication device will have insufficient energy left for a subsequent D2R transmission after the current complete D2R transmission (operation 530). Alternatively, or in addition, the first indication may indicate (explicitly or implicitly) that the communication device vvi 11 transition from the ON state to the SLEEP state (or the OFF state) after the current complete D2R transmission. Yet alternatively, the first indication may indicate a number of time windows (or duty cycles) that the communication device, which operates in a duty-cycle manner with pre-configured time windows for communications with the reader device, will skip (i.e., be unavailable for communications with the reader device). Then, execution of the process 500, by the communication device, may end.

[0088] In response to a determination, by the communication device during operation 525, that the communication device has sufficient energy left to stay in the ON state and to make another D2R transmission after sending the response that is being requested, execution of the process 500, by the communication device, can continue with the communication device sending a third D2R transmission to the reader device. In some implementations, the third D2R transmission includes the response being requested and a second indication indicating (explicitly or implicitly) that the communication device will have sufficient energy left for another D2R transmission after the current (third) D2R transmission (operation 535). Alternatively, or in addition, the second indication may indicate (explicitly or implicitly) that the communication device will stay in the ON state after the third D2R transmission. Yet alternatively, the second indication may indicate zero number of time window (or duty cycle) that the communication device, which operates in a duty-cycle manner wdth pre-configured time windows for communications wdth the reader device, will skip (i.e., the communicationFW 6000735PCT02 -20-device will not skip the next time w indow). Then, execution of the process 500, by the communication device, may end.

[0089] FIG.6 illustrates an example of a flowchart of a process 600 performed, by a communication device, to determine whether the communication device has sufficient energy to complete a messaging sequence. An example of the process 600 will be described below as being performed by a communication device such as the communication device 110a, 110b of the communication netw ork too to communicate with a reader device such as the reader device 120a, 120b of FIG. 1.

[0090] Execution of the process 600, by a communication device, can begin with the communication device receiving an R2D transmission for operation from a reader device (operation 610). In some implementations, for example, the received R2D transmission may have been sent, by a reader device, in response to a first A-IoT service request from an A-IoT core network (CN).

[0091] Execution of the process 600, by the communication device, continues with the communication device determining whether the communication device has enough energy to complete a messaging sequence associated with the received R2D transmission (operation 611). Determining whether the communication device has enough energy to complete the messaging sequence may include, for example, comparing, by the communication device, an energy status of the communication device to a threshold based on message type or message sequence. In some implementations, a messaging sequence can include only a single reception and transmission. Such messaging sequences comprising only a single reception and transmission may include, for example, a messaging sequence for a certain command. However, in other implementations, a messaging sequence can include multiple receptions and transmissions. Such messaging sequences comprising multiple receptions and transmissions can include, for example, a messaging sequence for inventory.

[0092] In response to a determination, by the communication device in operation 611, that the communication device does not have enough energy to complete the messaging sequence associated with the received R2D transmission, execution of the process 600 can continue with the communication device determining whether the communication device is to inform the reader of the condition of the communication device (i.e., that the communication device does not have enough energy to complete the message sequence associated with the received R2D transmission) (operation 612).

[0093] In response to a determination, by the communication device, that the communication device is not to inform the reader of the communication device inFW 6000735PCT02 -21-operation 612, the communication device may become unavailable (operation 614). In some implementations, becoming unavailable may include, for example, the communication device transitioning to a SLEEP state or an OFF state. In such a scenario, the communication device will not respond to the reader device and the reader device will interpret the lack of response of the communication device as an indication that the communication device failed to receive the R2D transmission, that the communication device was unable to receive the R2D transmission due to being unavailable, that the communication device was unable to initiate a response due to limited energy to complete the sequence, or that a D2R transmission was received in error (or failed due to insufficient energy).

[0094] Alternatively, in response to a determination, by the communication device during operation 612, that the communication device is to inform the reader of the communication device, the communication device may transmit a negative acknowledgement with information that indicates one or more energy conditions associated with the communication device (operation 613). In some implementations, the information can include one or more codes such as a one-byte code or a two-byte code that is configured to communicate one or more energy specific conditions described herein.

[0095] In some implementations, execution of the process 600 can continue during operation 611 with the communication device determining that the communication device has enough energy to complete a messaging sequence associated with the received R2D transmission (operation 611). In such implementations, execution of the process 600 can continue with the communication device determining to complete the messaging sequence operation (operation 615). In such instances, the communication device can continue communication of the message sequence(s) and then, in the last part of the D2R transmission, the communication device can include with information that indicates one or more energy conditions associated with the communication device in the last part of the D2R transmission (operation 613). In some implementations, the information can include one or more codes such as a one-byte code or a two-byte code that is configured to communicate one or more energy specific conditions described herein.

[0096] After the communication device sends the last part of the D2R transmission during operation 615, execution of process 600 can continue with the communication device determining whether the communication device has sufficient energy to remain in an ON state. The communication device may make this determination by, for example, comparing an energy status of the communication device to a threshold. If the comparison of the energy status of the communication device to the threshold satisfiesFW 6000735PCT02 -22-the threshold and the communication device determines that the communication device has sufficient energy to remain in an ON state, then execution of the process 600 can continue with the communication device receiving an R2D transmission for operation in operation 610. Alternatively, if the comparison of the energy status of the communication device to the threshold does not satisfy the threshold, then the communication device may determine to transition to a SLEEP state or an OFF state (operation 614). In such a scenario, the communication device will not respond to the reader device and the reader device will interpret the lack of response of the communication device as an indication that the communication device failed to receive the R2D transmission, that the communication device was unable to receive the R2D transmission due to being unavailable, that the communication device was unable to initiate a response due to limited energy to complete the sequence, or that a D2R transmission was received in error (or failed due to insufficient energy).

[0097] FIG. 7 illustrates an example state machine 700 and associated state transitions of a communication device. In some implementations, the state machine 700 describes state transitions of communication devices such as, e.g., the communication devices 110a, 110b of the communication system too in FIG. 1.

[0098] The state machine 700 describes the state transitions of a communication device between an ON state, a SLEEP state, and an OFF state. In example of state machine 700, the communication device can transition from the ON state 710 to the OFF state 730 w hen the communication device has insufficient power to retain its memory content or, in some implementations, when the communication device determines that the energy of the communication device is below a second threshold and informs a reader that the energy of the communication device is below the second threshold. This state transition is identified in FIG. 7 using the label eON-OFF. The state transition identified by the label eOFF-SLEEP indicates that a communication device 700 can transition from the OFF state 730 to the SLEEP state 720 when the energy status of the communication device satisfies another energy threshold. Due to a possible loss of memory contents, such a transition may not occur in practice.

[0099] In the example of state machine 700, the communication device 700 can transition from the SLEEP state 720 to the ON state 710 when the communication device is sufficiently charged to perform ON state operations. Alternatively, or in addition, this eSLEEP-ON state transition can occur when scheduling information from the last ON state indicates that the device can return to the ON state. This state transition is identified in FIG. 7 using the label eSLEEP-ON. Then, the communication device 700 can transition from the ON state 710 to the SLEEP state 720 when schedulingFW 6000735PCT02 -23-information indicates that the next opportunity for ON state operations is at some future time or the when the communication device informs the reader that its energy is below a first threshold. This state transition is identified in FIG. 7 using the label eON-SLEEP.

[0100] In the example of state machine 700, the communication device 700 can transition from the SLEEP state 720 to the OFF state 730 when communication device has insufficient energy to retain its memory content. This state transition is identified in FIG. 7 using the label eSLEEP-OFF. Then, the communication device 700 can transition from the OFF state 730 to the ON state 710 when the communication device is fully charged. Alternatively, in some implementations, the communication device 700 can transition from the OFF state 730 to the ON state 710 when the energy of the communication device is greater than the first threshold. This state transition is identified in FIG. 7 using the label eOFF-ON.[01011 FIG. 8 illustrates an example of a flowchart of a process 800 performed, by a communication device, as the communication device changes its operational state. An example of the process 800 will be described below as being performed by a communication device such as the communication device 110a, 110b of the communication network too to change its operational state to conserve energy and to improve its energy harvesting.

[0102] Execution of the process 800, by a communication device, can begin with the communication device receiving a message, from a reader device such as the reader device 120a, 120b of the communication network too, initiating a procedure and including filtering criteria that the communication device does not satisfy for participating in the procedure (operation 810). In some implementations, the received message may be based on an A-IoT paging message received from the reader device, which message is sent by the reader device to one or more communication devices to notify the communication devices other than the communication device that received the message in operation 810 to participate in the procedure. In some implementations, for example, the criteria indicated in the received message do not include any service(s) that the communication device supports and / or do not include any ID of the communication device or a group ID of any group to which the communication device belongs.

[0103] Execution of the process 800 can continue w ith the communication device estimating a duration for the procedure to complete based on information included in the message (operation 820). For example, the message received in operation 810 may include information indicating how many access slots that the reader provisions for the communication devices to send their responses in the current procedure. Then, theFW 6000735PCT02 -24-communication device may use the number of access slots provisioned to estimate the duration for the procedure to complete (e.g., for setting a timer of the device) or to estimate the number of triggering signals (such as Access Trigger messages) or other specific R2D signals expected (e.g., for setting a counter in the device). Alternatively, the reader may specifically include a first indication indicating the (expected) duration of the procedure or include a second indication indicating the number of a specific R2D signals expected during the procedure for devices, which are unable to participate in the procedure, to determine when the duration is expected to end.

[0104] Execution of the process 800 continues with the communication device transitioning its operational state from a first state (e.g., the ON state) to a second state (e.g., the SLEEP state) (operation 830). In some implementations, the communication device transitions from the first state to the second state because the communication device consumes less energy in the second state relative to the first state and may have a longer time to harvest energy when it is in the second state than when it is in the first state.

[0105] Execution of the process 800 continues with the communication device remaining in the second state until the communication device determines that the energy storage of the communication device has become full (or nearly full or above a threshold) or that the duration of time estimated in operation 820 has ended (operation 840). Then, in response to a determination that the energy storage of the communication device has become full (or nearly full) or that the duration of time estimated in operation 820 has ended, execution of the process 800 continues with the communication device transitioning its operational state from the second state back to the first state (operation 850). Once the communication device has transitioned back to the first state (e.g., the ON state), the communication device is able to resume its communication with the reader device. After the communication device has transitioned from the second state back to the first state and resumed communication with the reader device, execution of the process 800 is complete. In this way, the device may be able to conserve energy, spend more time harvesting energy by being in the second state, or both, without causing undue risks of missing opportunities to communicate with the reader device.

[0106] FIG. 9A illustrates an example flow diagram 900A of an example of communications between a reader device 920A and a communication device 910A. In some implementations, the reader device 920A is the same as the reader device 120a, 120b of the communication network too of FIG. 1 and the communication device 910A is the same as a communication device 110a, 110b of the communication network too of FIG. 1.FW 6000735PCT02 -25-

[0107] The process flow of flow diagram 900A begins with the reader device 920A broadcasting or multicasting an A-IoT paging message 950A. In some implementations, the A-IoT paging message that was broadcast or multicast in communication 950A includes information of filtering criteria for devices that can be used to indicate whether a communication device 910A is to participate in the procedure initiated by the A-IoT paging message broadcast or multicast in communication 950 A. In some implementations, the filtering criteria may include information indicating one or more communication device types, one or more service types that a communication device must support in order to be able to participate in the procedure, or a combination of both. In some implementations, the filtering criteria may include an ID of the device or a group ID of a group to which the communication device belongs.

[0108] In some implementations, the A-IoT paging message broadcast or multicast in communication 950A may further include information indicating an expected duration. The expected duration may include a time span, an expected number of triggering signals, other specific R2D signals during the time span, which start from the end of the A-IoT paging message for the entire procedure initiated by the A-IoT paging message to be finished. For example, the A-IoT paging message may include information indicating how many access slots that the reader provisions for the devices to provide their responses to the current A-IoT paging message.

[0109] Then, a communication device such as communication device 910A, which satisfies the criteria to participate in the procedure, generates a random number to select an access slot from the access slots provisioned by reader device 920A, and then transmits a D2R message referred to as the message 1 (Msgi), which carries a random ID of communication device 910A and hence is also be referred to as the Random ID message. Communication device 910A may monitor and count a specific type of R2D signals (such as the Access Trigger messages) received from reader device 920A to determine which access slot it should select to transmit its Msgi, based on its counting and the random number it has generated.

[0110] Then, once the communication device 910A determines that its selected access slot has arrived (e.g., the number of Access Trigger messages that it has received since receiving the paging message, multiplied by the number of access slots triggered by each Access Trigger message, have become greater than or equal to the random number it has generated, wherein the last received Access Trigger message causing the becoming is the trigger signal that immediately precedes the selected access slot for sending Msgi), the communication device 910A may begin communications with the reader device 920A. In the example of the flow diagram 900A, this includes the communication deviceFW 6000735PCT02 -26-9ioA sending a D2R transmission 954A, e.g., carrying its Msgt, to the reader device 920A after the reception of the trigger signal that immediately precedes its selected access slot, the reader device 920A sending an R2D transmission 956A, e.g., carrying an R2D message referred to as message 2 (Msg2), which is also referred to as the Random ID Response message, to the communication device 910A after receipt of the D2R transmission 954A, and then the communication device 910A transmitting a subsequent D2R transmission 958A, e.g., carrying a D2R message referred to as message 3 (Msg3), to the reader device after receipt of the R2D transmission 956A.

[0111] FIG. 9B illustrates an example flow diagram 900B of another example of communications between a reader device 920B and a communication device 910B. In some implementations, the reader device 920B is the same as the reader device 120a, 120b of the communication network too of FIG. 1 and the communication device 910B is the same as a communication device 110a, 110b of the communication network too of FIG. 1.

[0112] The process flow of flow diagram 900B begins the reader device 920B broadcasting or multicasting an A-IoT paging message 950B. In some implementations, the A-IoT paging message that was broadcast or multicast in communication 950B includes information of filtering criteria for devices that can be used to indicate whether a communication device 910B is to participate in the procedure initiated by the A-IoT paging message broadcast or multicast in communication 950B. In some implementations, the filtering criteria may include information indicating one or more communication device types, one or more service ty pes that a communication device must support in order to be able to participate in the procedure, or a combination of both. In some implementations, the filtering criteria may include an ID of the device or a group ID of a group to which the communication device belongs.

[0113] In some implementations, the A-IoT paging message broadcast or multicast in communication 950B may further include information indicating an expected duration. The expected duration may include a time span, an expected number of triggering signals, other specific R2D signals during the time span, which start from the end of the A-IoT paging message for the entire procedure initiated by the A-IoT paging message to be finished. For example, the A-IoT paging message may include information indicating how many access slots that the reader provisions for the devices to provide their responses to the current A-IoT paging message.

[0114] Then, a communication device such as communication device 910B, which does not satisfy the criteria to participate in the procedure, can use the informationFW 6000735PCT02 -27-indicating the expected duration such as, e.g., an indicated number of access slots to estimate the duration (in a time unit) for the procedure to complete (e.g., for starting a timer of the device w ith a value of the duration) or to estimate the number of triggering signals 952B communicated by the reader device 920B or other specific R2D signals expected (e.g., for starting a counter of the device to count the number of the specific R2D signals). Alternatively, the reader device 920B may specifically include a duration indication indicating the (expected) duration (which may be expressed either in a time unit or as a number of specific R2D signals) in the A-IoT paging message 950B.

[0115] After receipt of the A-IoT paging message 950B and after determining an estimated duration of the procedure that does not involve the communication device 910B, the communication device 910B may transition to a SLEEP state for the estimated duration. In some implementations, the communication dev ice 910B may monitor for the triggering signal 952B or other specific R2D signals and may use a counter to count the number of such signals transmitted to determine w hen the duration (e.g., as estimated by the communication device 910B or as indicated to the communication device 910B by the reader device 920A) ends.

[0116] If the communication device 910B is capable of running a clock during theSLEEP state, the communication device 910B may use a timer to determine when the duration ends. In either case, when the communication device 910B determines that the duration ends or it becomes fully charged (e.g., its energy storage becomes full) or near fully charged, the communication device 910B can transition to the ON state and resume normal operations. The reader device 920B may be unaware of when a communication device 910B performs a state transition. It is possible w hen a communication device 910B resumes normal operations, the communication device 910B may determine that it can transition back to the SLEEP state. For example, in some instances, a communication device 910B may have a fast clock due to the inaccuracy of the clock. In such instances, the communication device 910B may transition from the SLEEP state to the ON state earlier than the expected duration. If such an early transition occurs, the communication device 910B may decide to transition back to the SLEEP state for another duration.

[0117] If the communication device 910B is also capable of receiving subsequentR2D transmission(s) and decoding subsequent A-IoT paging message(s) carried in the subsequent R2D transmission(s) while it is in the SLEEP state, the communication device may further extend the duration for it to remain in the SLEEP state if it does not satisfy the criteria to participate in the procedure(s) initiated by the subsequent A-IoTFW 6000735PCT02 -28-paging message(s), until the extended duration expires or until the device becomes fully charged / almost fully charged, whichever comes first.

[0118] Then, after the communication device 910B determines that the estimated duration has expired, the communication device 910B can transition from the SLEEP state to the ON state and detect a subsequent A-IoT paging message 954B and determine whether the communication device 910B satisfies the filtering criteria in the A-IoT paging message 954B for involvement in the procedure specified by the paging message 954B.

[0119] In the above implementations described with reference to the flow diagrams 900A and 900B, the reader device 910A, 910B may estimate the operational state the communication device 910A, 910B, even without an explicit signaling from the communication device 910A, 910B indicating a current operation state of the communication device 910A, 910B or indicating that the communication device 910A has made a state transition. Based on the estimated operation state of the communication device 910A, 910B, the reader device 920A, 920B may change filtering criteria based on the availability of communication device 910A, 910B.

[0120] In the above implementations and various other implementations described below, the A-IoT paging message is used as an example of a message sent from the reader device 920A, 920B, wherein if a communication device 910A, 910B does not satisfy the criteria in (or associated with) the A-IoT paging message to participate in the subsequent communications initiated or triggered by the message and if the duration for the subsequent communications to complete is communicated to the communication device 910A, 910B or otherwise estimated by the communication device 910A, 910B, then the communication device 910A, 910B can transition its operational state from a first state (e.g., the ON state) to a second state (e.g., the SLEEP state) for the duration and the communication device 910A, 910B can return to the first state after the duration ends. This state transition enables the communication device 910A, 910B to generally consume less energy, spend more time to harvest energy when it is in the first state than when it is in the second state, or both.

[0121] However, messages other than the A-IoT paging message can also be used. For example, FIG. 10A illustrates an example flow diagram 1000A of another example of communications between a reader device 1020A and a first communication device 1015A and between the reader device 1020A and a second communication device 1010A that includes the second communication device 1010A sending of a device-to-reader (D2R) transmission sent via PDRCH that includes an energy status indicator (ESI).FW 6000735PCT02 -29-

[0122] With reference to the flow diagram 1000A, the reader device 1020A sends a triggering message 1050A via the physical reader to device channel (PRDCH) to initiate a dedicated (signaling and / or data) exchange with a first communication device 1015A and a second communication device 1010A, where the second communication device 1010A does not satisfy the criteria of the triggering message 1050A.

[0123] The second communication device 1010A may determine, based on an indication of a duration of a procedure indicated by the triggering message 1050A, an estimated duration of the procedure indicated by the triggering message 1050A. Then, with the duration for the dedicated exchange between the reader device 1020A to complete is known to a second communication device 1010A (e.g., being indicated in the triggering message) or can be estimated by the second communication device 1010A, or the end of the duration can be detected by the second communication device 1010A, then the second communication device 1010A can transition its operational state from the first state (e.g., ON state) to the second state (e.g., SLEEP state) for the duration and return to the first state after the duration ends, without causing undue risks of the second communication device 1010A missing opportunities to communicate with the reader device 1020A.

[0124] However, prior to transitioning from the first state to the second state, the second communication device 1010A may send a D2R transmission to the reader device 1020A via the PDRCH 1052A that includes one or more energy conditions. In some implementations, the one or more energy conditions can include an ESI of the second communication device 1010A, an operational state of the second communication dev ice 1010A, an energy-harvesting condition of the second communication device 1010A, an energy trend of the second communication device 1010A, a number of time windows (or duty cycles) that the second communication device 1010A will skip, a quantized energy level of the second communication device 1010A, or a combination thereof. The second communication device 1010A can send the D2R transmission that includes the one or more energy conditions and then transition from the first state to the second state, and remain in the second state until the estimated duration for the exchange between the reader device 1020A and the first communication device 1015A to expire. Then, upon expiration of the estimated duration of the exchange between the reader device 1020A and the first communication device 1015A, which can include PRDCH transmissions 1054A and 1056A from the reader 1020A and PDRCH transmissions 1052A from the second communication device 1010A, the second communication device 1010A can transition its operational state from the second state (e.g., SLEEP state) to the first stateFW 6000735PCT02 -30-(e.g., ON state) in order to continue communications with the reader device 1020A and receive a subsequent R2D transmission 1058A via the PRDCH.

[0125] FIG. 10B illustrates an example of a D2R transmission 1000B that includes an ESI 1050B.

[0126] In some implementations, a communication device such as 1010A may send a D2R transmission to a reader device such as reader device 1020A via the PDRCH that includes one or more energy conditions. In some implementations, the one or more energy conditions can include an ESI 1050 B of the second communication device 1010A, as shown in FIG. 10B.

[0127] Though an example of a PDRCH that includes an ESI is described, the present disclosure is not so limited. Instead, in other implementations, the one or more energy conditions indicated via the PDRCH can include an operational state of the second communication device 1010A, an energy-harvesting condition of the second communication device 1010A, an energy trend of the second communication device 1010A, a number of time windows (or duty cycles) that the second communication device 1010A will skip, a quantized energy level of the second communication device 1010A, or a combination thereof.

[0128] FIG. 11 illustrates an example of another flowchart of a method 1100 performed, by a communication device (e.g., an AIoT device), to indicate one or more energy-related conditions or availability to a reader device, in accordance with some implementations. The communication device may include computer-readable code or instructions executing on one or more processors of the communication device. Coding of the software for carrying out or performing the method 1100 is well within the scope of a person of ordinary’ skill in the art having regard to the present disclosure. The method 1100 may include additional or fewer operations than those shown and described and may be carried out or performed in a different order. Computer-readable code or instructions of the software executable by the one or more processors may be stored on at least one non-transitory computer-readable medium, such as for example, at least one memory’ of the communication device. In some embodiments, the method 1100 may be performed by one or more of units or modules (e.g., an integrated circuit) of the communication device, such as field programmable gate arrays (FPGAs) or applicationspecific integrated circuits (ASICs).

[0129] The method 1100 starts at the operation 1102, where the communication device receives a first message from a reader device. After receiving the first message, at the operation 1104, the communication device selects a response message from anFW 6000735PCT02 -31-expected response message and a negative acknowledgement message in accordance w ith a comparison of an energy threshold and an amount of energy stored at the communication device. The expected response message is selected in accordance w ith the comparison indicating that the amount of energy stored at the communication device is sufficient to transmit the expected response message. The negative acknowledgement message is selected in accordance with the comparison indicating that the amount of energy stored at the communication device is insufficient to transmit the expected response message. At the operation 1106, the communication device transmits to the reader device a device-to-reader (D2R) transmission that comprises the response message and at least one indicator of one or more energy-related conditions of the communication device.

[0130] In some implementations, the at least one indicator of the one or more energy-related conditions may comprise a first indicator indicating an energy trend of the communication device. The first indicator may be set to a first value in accordance with an increase in the amount of energy stored at the communication device. The first value indicates the increase in the amount of energy stored at the communication device. The first indicator may be set to a second value in accordance w ith a decrease in the amount of energy stored at the communication device. The second value indicating the decrease in the amount of energy stored at the communication device.

[0131] In some implementations, the at least one indicator may comprise a second indicator indicating an energy-harvesting condition of the communication device. The second indicator may be set to a third value in accordance with the communication device being able to harvest sufficient energy. The third value indicates that the communication device is able to harvest sufficient energy. The second indicator may be set to a fourth value in accordance with the communication device being unable to harvest sufficient energy. The fourth value indicates that the communication device is unable to harvest sufficient energy.

[0132] In some implementations, the at least one indicator may comprise a third indicator indicating an availability of the communication device for communications with the reader device after the D2R transmission is sent. The availability may be set to be available in accordance with the amount of energy stored at the communication device being greater than or equal to a second energy threshold. The availability may be set to be unavailable in accordance with the amount of energy stored at the communication device being less than the second energy threshold.FW 6000735PCT02 -32-

[0133] In some implementations, the third indicator may be set to a fifth value indicating that the communication device remains in an ON state after the D2R transmission is sent. In some implementations, the third indicator may be set to a sixth value indicating that the communication device is in an OFF state or a SLEEP state after the D2R transmission is sent.

[0134] In some implementations, the communication device may be configured with time windows for monitoring for the first message. A configuration for the time windows may comprise a duration for the monitoring within each of the time windows and a periodicity of the time windows. The at least one indicator of the one or more energy- related conditions may comprise a fourth indicator indicating a number of time windows that the communication device will be unavailable for communications with the reader device.

[0135] In some implementations, the duration and the periodicity may be measured as respective numbers of a specific R2D signal received.

[0136] In some implementations, the at least one indicator of the one or more energy-related conditions may comprise a fifth indicator indicating an estimate of a remaining energy of the communication device.

[0137] In some implementations, the first message may comprise a paging message.

[0138] In some implementations, the energy threshold may be a second amount of energy for the transmission of the expected response message.

[0139] FIG. 12 illustrates an example of another flowchart of a method 1200 performed, by a reader device, to schedule transmission of a reader-to-device (R2D) message, in accordance with some implementations. The reader device may include computer-readable code or instructions executing on one or more processors of the reader device. Coding of the software for carrying out or performing the method 1200 is well within the scope of a person of ordinary7skill in the art having regard to the present disclosure. The method 1200 may include additional or fewer operations than those shown and described and may be carried out or performed in a different order. Computer-readable code or instructions of the software executable by the one or more processors may be stored on at least one non-transitory computer- readable medium, such as for example, at least one memory of the reader device. In some embodiments, the method 1200 may be performed by one or more of units or modules (e.g., an integrated circuit) of the reader device, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).FW 6000735PCT02 -33-

[0140] The method 1200 starts at the operation 1202, where the reader device transmits a first message to a communication device. In response to transmitting the first message, at the operation 1204, the reader device receives a device-to-reader (D2R) transmission that comprises a response message and at least one indicator of one or more energy-related conditions of the communication device after the communication device sends the D2R transmission. A length of the response message is a first length of an expected response message or a second length of a negative acknowledgement message. The first length of the expected response message is greater than the second length of the negative acknowledgement message. The first length of the expected response message is indicated in the first message. The expected response message is received in accordance with the communication device having energy to transmit the response message of the first length. The negative acknowledgement message is received in accordance with the communication device having insufficient energy to transmit the response message of the first length. At the operation 1206, the reader device schedules a reader-to-device (R2D) transmission in accordance with an availability of the communication device to receive the reader-to-device (R2D) transmission based on the at least one indicator of the one or more energy- related conditions and the response message.

[0141] In some implementations, the at least one indicator of the one or more energy-related conditions may indicate an energy trend of the communication device or an energy-harvesting condition of the communication device.

[0142] In some implementations, the at least one indicator of the one or more energy-related conditions of the communication device may indicate that the communication device is available for communications with the reader device. The at least one indicator may be set to a first value to indicate that the communication device has sufficient energy for another D2R transmission.

[0143] In some implementations, the at least one indicator of the one or more energy-related conditions of the communication device may indicate that the communication device is unavailable for communications with the reader device. The at least one indicator may be set to a second value to indicate that the communication device has insufficient energy for another D2R transmission.

[0144] In some implementations, the reader device may schedule the R2D transmission by determining an estimated remaining energy of the communication device based on the at least one indicator of the one or more energy- related conditions and one or more other attributes associated with the communication device.FW 6000735PCT02 -34-

[0145] In some implementations, the reader device may transmit the R2D transmission to the communication device.

[0146] In some implementations, the reader device may anticipate another D2R transmission from the communication device within a time window. The another D2R transmission may comprise another expected message or another negative acknowledgement. The another D2R transmission may further comprise a second indicator of a second one or more energy-related conditions of the communication device. The reader device may adjust the estimated remaining energy of the communication device in accordance with receiving the another D2R transmission or an absence of receiving the another D2R transmission in the time window-.

[0147] In some implementations, the one or more other attributes associated with the communication device may comprise one or more of a duration of the D2R transmission of the communication device, one or more respective durations of one or more past D2R transmissions of the communication device, an operational state of the communication device, a task being performed by the communication device, a location of the communication device, a distance between the communication device and the reader device, energy harvested by the communication device over a past time period, or a time of day.

[0148] In some implementations, the reader device may send the R2D transmission to the communication device. The reader device may determine whether the R2D transmission was successful. The reader device may adjust one or more parameters of a machine learning model, based on w-hether the R2D transmission was successful.

[0149] In some implementations, the first message may comprise a paging message.

[0150] FIG. 13 illustrates an example of a communications system. Communication system 1300 includes a base station 1310 with coverage area 1301. The base station 1310 serves a plurality of user equipments (UEs), including UEs 1320. Transmissions from the base station 1310 to a UE is referred to as a downlink (DL) transmission and occurs over a downlink channel (shown in FIG. 13A as a solid arrow-ed line 1335), while transmissions from a UE to the base station 1310 is referred to as an uplink (UL) transmission and occurs over an uplink channel (shown in FIG. 13A as a dashed arrow-ed line 1330). Data carried over the uplink / downlink connections may include data communicated between the UEs 1320, as well as data communicated to / from a remoteend (not shown) by way of a backhaul network 1315. Example downlink channels and signals include synchronization signal (SS) blocks, also called SS / physical broadcast channel (PBCH) block SS / PBCH block (SSB), physical dow nlink shared channelFW 6000735PCT02 -35-(PDSCH), physical dow nlink control channel (PDCCH), channel state information reference signal (CSI-RS) which includes tracking RS (TRS, aka CSI-RS for tracking), etc. Example uplink channels and signals include physical uplink shared channel (PUSCH), physical uplink control channel (PUCCH), an uplink sounding reference signal (SRS), or physical random access channel (PRACH). The transmissions may be periodic, semi- persistent, or aperiodic. For example, P TRS stands for periodic TRS, AP TRS stands for aperiodic TRS, SP CSI-RS stands for semi-persistent CSI-RS, P SSB / SP SSB / AP SSB stand for periodic- / -semi-persistent / aperiodic SSB, and so on. Sendees may be provided to the plurality of UEs by service providers connected to the base station 1310 through the backhaul network 1315, such as the Internet. The wireless communication system 1300 may include multiple distributed access nodes 1310.

[0151] In a typical communication system, there are several operating modes. In a cellular operating mode, communications to and from the plurality of UEs go through the base station 1310, while in device to device communications mode, such as proximity services (ProSe) operating mode, for example, direct communication between UEs is possible. As used herein, the term “base station” refers to any component (or collection of components) configured to provide wireless access to a network. Base stations may also be commonly referred to as Node Bs, evolved Node Bs (eNBs), next generation (NG) Node Bs (gNBs), master eNBs (MeNBs), secondary eNBs (SeNBs), master gNBs (MgNBs), secondary’ gNBs (SgNBs), network controllers, control nodes, access nodes, access points (APs), transmission points (TPs), transmission-reception points (TRPs), cells, carriers, macro cells, femtocells, pico cells, relays, customer premises equipment (CPE), the network side, the network, and so on. In the present disclosure, the terms “base station” and “TRP” are used interchangeably unless otherwise specified. As used herein, the term “UE” refers to any component (or collection of components) capable of establishing a wireless connection with a base station. UEs may also be commonly referred to as mobile stations, mobile devices, mobiles, terminals, user terminals, users, subscribers, stations, communication devices, CPEs, relays, Integrated Access and Backhaul (IAB) relays, and the like. It is noted that when relaying is used (based on relays, picos, CPEs, and so on), especially multi-hop relaying, the boundary’ between a controller and a node controlled by the controller may become blurry , and a dual node (e.g., either the controller or the node controlled by the controller) deployment w here a first node that provides configuration or control information to a second node is considered to be the controller. Likewise, the concept of UL and DL transmissions can be extended as well.FW 6000735PCT02 -36-

[0152] A cell may include one or more bandwidth parts (BWPs) for UL or DL allocated for a UE. Each BWP may have its own BWP-specific numerology and configuration, such as the BWP’s bandwidth. It is noted that not all BWPs need to be active at the same time for the UE. A cell may correspond to one carrier, and in some cases, multiple carriers. Typically, one cell (a primary cell (PCell) or a secondary cell (SCell), for example) is a component carrier (a primary component carrier (PCC) or a secondary’ CC (SCC), for example). For some cells, each cell may include multiple carriers in UL, one carrier may be referred to as an UL carrier or non-supplementary UL (non- SUL, or simply UL) carrier which has an associated DL, and other carriers are called supplementary UL (SUL) carriers which do not have an associated DL. A cell, or a carrier, may be configured with slot or subframe formats comprising DL and UL sy mbols, and that cell or carrier may be seen as operating in a time division duplexed (TDD) mode. In general, for unpaired spectrum, the cells or carriers are in TDD mode, and for paired spectrum, the cells or carrier are in a frequency division duplexed (FDD) mode. For TDD mode, the same spectrum resources can be used for UL or DL at different time durations, where the time durations allocated for UL or DL are configured statically or indicated dynamically, and the center frequencies for TDD UL (as in TDD UL BWP or generally UL resources used in a certain process) and TDD DL (as in TDD DL BWP or generally DL resources used in a certain process) are aligned. For FDD mode, one part of the paired spectrum is used for UL all the times and the other part is used for DL all the times. A transmission time interval (TTI) generally corresponds to a subframe (in LTE) or a slot (in NR). Access nodes may provide wireless access in accordance with one or more wireless communication protocols, e.g., long term evolution (LTE), LTE advanced (LTE- A), 5G, 5G LTE, 5G NR, future 5G NR releases, 6G, High Speed Packet Access (HSPA), Wi-Fi 802.na / b / g / n / ac, etc. While it is understood that communication systems may employ multiple access nodes (or base stations) capable of communicating with a number of UEs, only one access node, and two UEs are illustrated in FIG. 13 for simplicity.

[0153] A way to increase the network resources is to utilize more usable spectrum resources, which include not only the licensed spectrum resources of the same type as the macro, but also the licensed spectrum resources of a different type as the macro (e.g., the macro is a FDD cell but a small cell may use both FDD and TDD carriers), as well as unlicensed spectrum resources and shared-licensed spectrums. Some of the spectrum resources lie in high-frequency’ bands, such as 6GHz to 60GHz, 70GHz, and even up to 300GHz (sub-TeraHz). The unlicensed spectrums may be used by generally any user, subject to regulatory requirements. The shared-licensed spectrums are also not exclusiveFW 6000735PCT02 -37-for an operator to use. Traditionally, the unlicensed spectrums are not used by cellular networks because it is generally difficult to ensure quality of service (QoS) requirements. Operating on the unlicensed spectrums mainly includes wireless local area networks (WLAN), e.g., the Wi-Fi networks. Due to the fact that the licensed spectrum is generally scarce and expensive, utilizing the unlicensed spectrum by the cellular operator may be considered. Note that on high-frequency bands and unlicensed / shared-licensed bands, typically TDD is used and hence the channel reciprocity can be exploited for the communications.

[0154] In a realistic deployment, a gNB may control one or more cells. Multiple remote radio units may be connected to the same baseband unit of the gNB by fiber cable, and the latency between baseband unit and remote radio unit is quite small. Therefore, the same baseband unit can process the coordinated transmission / reception of multiple cells. For example, the gNB may coordinate the transmissions of multiple cells to a UE, w hich is called coordinated multiple point (CoMP) or multi-TRP (mTRP, M-TRP) transmission. The gNB may also coordinate the reception of multiple cells from a UE, which is called CoMP / M-TRP reception. In this case, the backhaul link between these cells with the same gNB is a fast backhaul, and the scheduling of data transmitted in different cells for the UE can be easily coordinated in the same gNB. The backhaul connections may also be ones with longer latency and lower transmission rates.

[0155] FIG. 14 illustrates another example of a communications system 1400. In general, the system 1400 enables multiple wireless or wired users to transmit and receive data and other content. The system 1400 may implement one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), or non-orthogonal multiple access (NOMA).

[0156] In this example, the communication system 1400 includes electronic devices (ED) 14103-14100, radio access networks (RANs) I42oa-i42ob, a core network 1430, a public switched telephone network (PSTN) 1440, the Internet 1450, and other networks 1460. While certain numbers of these components or elements are shown in FIG. 14, any number of these components or elements may be included in the system 1400.

[0157] The EDs 14103-14100 are configured to operate or communicate in the system 1400. For example, the EDs 14103-14100 are configured to transmit or receive via wireless or wired communication channels. Each ED 14103-14100 represents any suitable end user device and may include such devices (or may be referred to) as a user equipment or device (UE), wireless transmit or receive unit (WTRU), mobile station,FW 6000735PCT02 -38-fixed or mobile subscriber unit, cellular telephone, personal digital assistant (PDA), smartphone, laptop, computer, touchpad, w ireless sensor, A-IoT device (e.g., for asset management), or consumer electronics device.

[0158] The RANs I42oa-i42ob here include base stations i470a-t470b, respectively. Each base station i470a-t470b is configured to wirelessly interface w ith one or more of the EDs I4ioa-t4toc to enable access to the core network 1430, the PSTN 1440, the Internet 1450, or the other networks 1460. For example, the base stations 14703-1470b may include (or be) one or more of several well-known devices, such as a base transceiver station (BTS), a Node-B (NodeB), an evolved NodeB (eNB), a Next Generation (NG) NodeB (gNB), a gNB centralized unit (gNB-CU), a gNB distributed unit (gNB-DU), a Home NodeB, a Home eNodeB, a site controller, an access point (AP), or a wireless router. The EDs 14103-14100 are configured to interface and communicate w ith the Internet 1450 and may access the core network 1430, the PSTN 1440, or the other networks 1460.

[0159] In the embodiment shown in FIG. 14, the base station 1470a forms part of the RAN 1420a, which may include other base stations, elements, or devices. Also, the base station 1470b forms part of the RAN 1420b, which may include other base stations, elements, or devices. Each base station 14703-1470b operates to transmit or receive wireless signals within a particular geographic region or area, sometimes referred to as a “cell.” In some embodiments, multiple-input multiple-output (MIMO) technology may be employed having multiple transceivers for each cell.

[0160] The base stations i470a-i470b communicate with one or more of the EDs 14103-14100 over one or more air interfaces 1490 using wireless communication links. The air interfaces 1490 may utilize any suitable radio access technology.

[0161] It is contemplated that the system 1400 may use multiple channel access functionality, including such schemes as described above. In particular embodiments, the base stations and EDs implement 5G New Radio (NR), LTE, LTE-A, or LTE-B. Of course, other multiple access schemes and wireless protocols may be utilized.

[0162] The RANs I42oa-t42ob are in communication with the core netw-ork 1430 to provide the EDs 14103-14100 with voice, data, application, Voice over Internet Protocol (VoIP), or other sendees. Understandably, the RANs I42oa-i42ob or the core network 1430 may be in direct or indirect communication with one or more other RANs (not sho Ti). The core network 1430 may also sene as a gateway access for other networks (such as the PSTN 1440, the Internet 1450, and the other networks 1460). In addition, some or all of the EDs 14103-14100 may include functionality for communicating withFW 6000735PCT02 -39-different wireless networks over different wireless links using different wireless technologies or protocols. Instead of wireless communication (or in addition thereto), the EDs may communicate via wired communication channels to a service provider or switch (not shown), and to the Internet 1450.

[0163] Although FIG. 14 illustrates one example of a communication system, various changes may be made to FIG. 14. For example, the communication system 1400 could include any number of EDs, base stations, networks, or other components in any suitable configuration.

[0164] FIGs. 15A and 15B illustrate example devices that may implement the methods and teachings according to this disclosure. In particular, FIG. 15A illustrates an example ED 1510, and FIG. 15B illustrates an example base station 1570. The ED 1510 and the base station 1570 may communicate over the air interface 1590. These components could be used in the system 1400 or in any other suitable system.

[0165] As shown in FIG. 15A, the ED 1510 includes at least one processing unit 1500. The processing unit 1500 implements various processing operations of the ED 1510. For example, the processing unit 1500 could perform signal coding, data processing, power control, input / output processing, or any other functionality enabling the ED 1510 to operate in the system 1700. The processing unit 1500 also supports the methods and teachings described in more detail above. Each processing unit 1500 includes any suitable processing or computing device configured to perform one or more operations. Each processing unit 1500 could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit. The ED 1510 may also be referred to as user equipment or UE herein.

[0166] The ED 1510 also includes at least one transceiver 1502. The transceiver 1502 is configured to modulate data or other content for transmission by at least one antenna or NIC (Network Interface Controller) 1504. The transceiver 1502 is also configured to demodulate data or other content received by the at least one antenna 1504. Each transceiver 1502 includes any suitable structure for generating signals for wireless or wired transmission or processing signals received wirelessly or by wire. Each antenna 1504 includes any suitable structure for transmitting or receiving wireless or wired signals. One or multiple transceivers 1502 could be used in the ED 1510, and one or multiple antennas 1504 could be used in the ED 1510. Although shown as a single functional unit, a transceiver 1502 could also be implemented using at least one transmitter and at least one separate receiver.FW 6000735PCT02 -40-

[0167] The ED 1510 further includes one or more input / output devices 1506 or interfaces (such as a wired interface to the Internet 1450). The input / output devices 1506 facilitate interaction with a user or other devices (network communications) in the network. Each input / output device 1506 includes any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen, including network interface communications.

[0168] In addition, the ED 1510 includes at least one memory 1508. The memory' 1508 stores instructions and data used, generated, or collected by the ED 1510. For example, the memory 1508 could store software or fi rm ware instructions executed by the processing unit(s) tsoo and data used to reduce or eliminate interference in incoming signals. Each memory tso8 includes any suitable volatile or non-volatile storage and retrieval device(s). Any suitable type of memory may be used, such as random access memory' (RAM), read only memory' (ROM), hard disk, optical disc, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory' card, and the like.

[0169] As shown in FIG. 15B, the base station 1570 includes at least one processing unit 1550, at least one transceiver 1552, which includes functionality for a transmitter and a receiver, one or more antennas 1556, at least one memory 1558, and one or more input / output deuces or interfaces 1566. A scheduler, which would be understood by one skilled in the art, is coupled to the processing unit 1550. The scheduler could be included within or operated separately from the base station 1570. The processing unit 1550 implements various processing operations of the base station 1570, such as signal coding, data processing, power control, input / output processing, or any other functionality. The processing unit t55O can also support the methods and teachings described in more detail above. Each processing unit 1550 includes any suitable processing or computing device configured to perform one or more operations. Each processing unit 1550 could, for example, include a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application specific integrated circuit.

[0170] Each transceiver 1552 includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each transceiver 1552 further includes any suitable structure for processing signals received wirelessly or by wire from one or more EDs or other devices. Although shown combined as a transceiver 1552, a transmitter and a receiver could be separate components. Each antenna 1556 includes any suitable structure for transmitting or receiving wireless or wired signals. While a common antenna 1556 is shown here as being coupled to the transceiver 1552, one or more antennas 1556 could be coupled to the transceiver(s) 1552, allowing separate antennas 1556 to be coupled to the transmitter and the receiver ifFW 6000735PCT02 -41-equipped as separate components. Each memory 1558 includes any suitable volatile or non-volatile storage and retrieval device(s). Each input / output device 1566 facilitates interaction w ith a user or other devices (network communications) in the network. Each input / output device 1566 includes any suitable structure for providing information to or receiving / providing information from a user, including network interface communications.

[0171] FIG. 16 illustrates an example of a computing system that may be used for implementing the devices and methods described herein. For example, the computing system can be any entity of UE, access network (AN), mobility management (MM), session management (SM), user plane gateway (UPGW), or access stratum (AS). Specific devices may utilize all of the components shown or only a subset of the components, and levels of integration may vary from device to device. Furthermore, a device may contain multiple instances of a component, such as multiple processing units, processors, memories, transmitters, receivers, etc. The computing system 1600 includes a processing unit 1602. The processing unit includes a central processing unit (CPU) 1614, memory’ 1608, and may further include a mass storage device 1604, a video adapter 1610, and an I / O interface 1612 connected to a bus 1620.

[0172] The bus 1620 may be one or more of any type of several bus architectures including a memory bus or memory controller, a peripheral bus, or a video bus. The CPU 1614 may comprise any type of electronic data processor. The memory 1608 may comprise any type of non-transitory system memory such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), or a combination thereof. In an embodiment, the memory 1608 may include ROM for use at boot-up, and DRAM for program and data storage for use while executing programs.

[0173] The mass storage 1604 may comprise any type of non-transitory storage device configured to store data, programs, and other information and to make the data, programs, and other information accessible via the bus 1620. The mass storage 1604 may comprise, for example, one or more of a solid state drive, hard disk drive, a magnetic disk drive, or an optical disk drive.

[0174] The video adapter 1610 and the I / O interface 1612 provide interfaces to couple external input and output devices to the processing unit 1602. As illustrated, examples of input and output devices include a display 1618 coupled to the video adapter 1610 and a mouse, keyboard, or printer 1616 coupled to the I / O interface 1612. Other devices maybe coupled to the processing unit 1602, and additional or fewer interface cards may beFW 6000735PCT02 -42-utilized. For example, a serial interface such as Universal Serial Bus (USB) (not shown) may be used to provide an interface for an external device.

[0175] The processing unit 1602 also includes one or more network interfaces 1606, which may comprise wired links, such as an Ethernet cable, or wireless links to access nodes or different networks. The network interfaces 1606 allow- the processing unit 1602 to communicate with remote units via the networks. For example, the network interfaces 1606 may provide wireless communication via one or moretransmitters / transmit antennas and one or more receivers / receive antennas. In an embodiment, the processing unit 1602 is coupled to a local-area network 1622 or a wide-area network for data processing and communications with remote devices, such as other processing units, the Internet, or remote storage facilities.[01761 It should be appreciated that not all components in the devices described in FIGs. 15-16 are required. In a non-limiting example, the ED 1510 maybe implemented as an A-IoT device 1510. But, the A-IoT device 1510 may not include an input / output devices 1506 for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen. The transceiver 1502 of the A-IoT device 1510 may be capable of transmitting by backscattering a radio wave received, instead of by generating the radio wave, for wireless communication purpose. In another non-limiting example, the system 1600 may be implemented as an A-IoT device 1600 that does not include or use the mass storage device 1604, the video adapter 1610, the mouse, keyboard, or printer 1616, or the display 1618.

[0177] It should be appreciated that one or more steps of the embodiment methods provided herein may be performed by corresponding units or modules. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by a performing unit or module, a generating unit or module, an obtaining unit or module, a setting unit or module, an adjusting unit or module, an increasing unit or module, a decreasing unit or module, a determining unit or module, a modifying unit or module, a reducing unit or module, a removing unit or module, or a selecting unit or module. The respective units or modules may be hardware, software, or a combination thereof. For instance, one or more of the units or modules may be an integrated circuit, such as field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs).

[0178] Although the description has been described in detail, it should be understood that various changes, substitutions and alterations can be made without departing from the spirit and scope of this disclosure as defined by the appended claims. Moreover, theFW 6000735PCT02 -43-scope of the disclosure is not intended to be limited to the particular embodiments described herein, as one of ordinary skill in the art w ill readily appreciate from this disclosure that processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, may perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include w ithin their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.FW 6000735PCT02 -44-

Claims

WHAT IS CLAIMED IS:

1. A method, comprising: receiving, by a communication device from a reader device, a first message; after the receiving the first message, selecting, by the communication device, a response message from an expected response message and a negative acknowledgement message, wherein the selecting the response message is in accordance with a comparison of an energy threshold and an amount of energy stored at the communication device, wherein the expected response message is selected in accordance with the comparison indicating that the amount of energy stored at the communication device is sufficient to transmit the expected response message, and wherein the negative acknowledgement message is selected in accordance with the comparison indicating that the amount of energy stored at the communication device is insufficient to transmit the expected response message; and transmitting, by the communication device to the reader device, a device-to- reader (D2R) transmission that comprises the response message and at least one indicator of one or more energy-related conditions of the communication device.

2. The method of claim 1, wherein the at least one indicator of the one or more energy-related conditions comprises a first indicator indicating an energy trend of the communication device, and wherein: the first indicator is set to a first value in accordance with an increase in the amount of energy stored at the communication device, the first value indicating the increase in the amount of energy stored at the communication device, or the first indicator is set to a second value in accordance with a decrease in the amount of energy stored at the communication device, the second value indicating the decrease in the amount of energy stored at the communication device.

3. The method of claim 1, wherein the at least one indicator comprises a second indicator indicating an energy-harvesting condition of the communication device, and wherein: the second indicator is set to a third value in accordance with the communication device being able to harvest sufficient energy, the third value indicating that the communication device is able to harvest sufficient energy, or the second indicator is set to a fourth value in accordance with theFW 6000735PCT02 -45-communication device being unable to harvest sufficient energy, the fourth value indicating that the communication device is unable to harvest sufficient energy.

4. The method of claim 1, wherein the at least one indicator comprises a third indicator indicating an availability of the communication device for communications with the reader device after the D2R transmission is sent, and wherein: the availability is set to be available in accordance with the amount of energy stored at the communication device being greater than or equal to a second energy threshold, or the availability is set to be unavailable in accordance with the amount of energy stored at the communication device being less than the second energy threshold.

5. The method of claim 4, wherein the third indicator is set to a fifth value indicating that the communication device remains in an ON state after the D2R transmission is sent, or wherein the third indicator is set to a sixth value indicating that the communication device is in an OFF state or a SLEEP state after the D2R transmission is sent.

6. The method of claim 1, wherein the communication device is configured with time windows for monitoring for the first message, wherein a configuration for the time windows comprises a duration for the monitoring within each of the time windows and a periodicity of the time windows, and wherein the at least one indicator of the one or more energy-related conditions comprises a fourth indicator indicating a number of time windows that the communication device will be unavailable for communications with the reader device.

7. The method of claim 6, wherein the duration and the periodicity are measured as respective numbers of a specific reader-to-device (R2D) signal received.

8. The method of claim 1, wherein the at least one indicator of the one or more energy-related conditions comprises a fifth indicator indicating an estimate of a remaining energy of the communication device.

9. The method of any of claims 1-8, the first message comprising a paging message.FW 6000735PCT02 -46-10. The method of any of claims 1-8, wherein the energy threshold is a second amount of energy for the transmission of the expected response message.

11. A method, comprising: transmitting, by a reader device to a communication device, a first message; receiving, by the reader device in response to the transmitting the first message, a device-to-reader (D2R) transmission that comprises a response message and at least one indicator of one or more energy-related conditions of the communication device after the communication device sends the D2R transmission, wherein a length of the response message is a first length of an expected response message or a second length of a negative acknowledgement message, wherein the first length of the expected response message is greater than the second length of the negative acknowledgement message, wherein the first length of the expected response message is indicated in the first message, wherein the expected response message is received in accordance w ith the communication device having energy to transmit the response message of the first length, and wherein the negative acknowledgement message is received in accordance with the communication device having insufficient energy to transmit the response message of the first length; and scheduling, by the reader device, a reader-to-device (R2D) transmission in accordance with an availability of the communication device to receive the reader-to- device (R2D) transmission based on the at least one indicator of the one or more energy- related conditions and the response message.

12. The method of claim 11, wherein the at least one indicator of the one or more energy-related conditions indicates an energy trend of the communication device or an energy-harvesting condition of the communication device.

13. The method of claim 11, wherein the at least one indicator of the one or more energy-related conditions of the communication device indicates that the communication device is available for communications with the reader device, and the at least one indicator is set to a first value to indicate that the communication device has sufficient energy for another D2R transmission.FW 6000735PCT02 -47-14- The method of claim 11, wherein the at least one indicator of the one or more energy-related conditions of the communication device indicates that the communication device is unavailable for communications with the reader device, and the at least one indicator is set to a second value to indicate that the communication device has insufficient energy for another D2R transmission.

15. The method of any of claims 11-14, wherein the scheduling the R2D transmission comprises: determining, by the reader device, an estimated remaining energy of the communication device based on the at least one indicator of the one or more energy- related conditions and one or more other attributes associated with the communication device.

16. The method of claim 15, further comprising: transmitting, by the reader device, the R2D transmission to the communication device; anticipating, by the reader device, another D2R transmission from the communication device within a time window, wherein the another D2R transmission comprises another expected message or another negative acknowledgement, the another D2R transmission further comprises a second indicator of a second one or more energy- related conditions of the communication device; and adjusting, by the reader device, the estimated remaining energy of the communication device in accordance with receiving the another D2R transmission or an absence of receiving the another D2R transmission in the time window.

17. The method of claim 15, wherein the one or more other attributes associated with the communication device comprise one or more of a duration of the D2R transmission of the communication device, one or more respective durations of one or more past D2R transmissions of the communication device, an operational state of the communication device, a task being performed by the communication device, a location of the communication device, a distance between the communication device and the reader device, energy harvested by the communication device over a past time period, or a time of day.

18. The method of claim 15, further comprising: sending, by the reader device, the R2D transmission to the communication device;FW 6000735PCT02 -48-determining, by the reader device, whether the R2D transmission was successful; and adjusting, by the reader device, one or more parameters of a machine learning model, based on whether the R2D transmission was successful.

19. The method of any of claims 11-14, the first message comprising a paging message.

20. A communication device comprising: at least one processor; and a non-transitory computer readable storage medium storing programming, the programming including instructions that, when executed by the at least one processor, cause the communication device to perform a method according to any of claims 1-10.

21. A reader device comprising: at least one processor; and a non-transitory computer readable storage medium storing programming, the programming including instructions that, when executed by the at least one processor, cause the reader device to perform a method according to any of claims 11-19.

22. A non-transitory computer-readable storage medium having instructions stored thereon that, when executed by a communication device, cause the communication device to perform a method according to any of claims 1-10.

23. A non-transitory computer-readable storage medium having instructions stored thereon that, when executed by a reader device, cause the reader device to perform a method according to any of claims 11-19.FW 6000735PCT02 -49-

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