Secure communications initiated by an ambient power device using wireless refractory technology

Abstract

One method involves backscattering, by means of an ambient power device (AMP device) that absorbs ambient energy, radio frequency (RF) energy received in a wireless signal by at least one powered wireless device or wireless helper device. The method involves causing the AMP device to transmit an initialization request frame within a backscattered signal to the powered wireless device using a first spreading code. The first spreading code may encode a predetermined bit pattern detectable by the powered wireless device and an identifier (ID) of the AMP device.The procedure involves the AMP receiving an ID request frame from the powered wireless device in response to the powered wireless device detecting the initialization request frame and recognizing the AMP device's ID. The ID request frame can then initiate an attempt to establish an encrypted wireless communication session with the powered wireless device.

Description

AREA OF TECHNOLOGY

[0001] This disclosure relates to wireless devices and, more specifically, secure communications initiated by an Ambient Power Device (AMP device) using wireless backscattering. GENERAL STATE OF THE ART

[0002] Wireless radio frequency (RF) devices have evolved in their nature and capabilities. In some wireless local area networks (WLANs), ambient power devices (AMP devices), which draw energy from the environment, can be effectively used as cost-effective wireless data collection sensors. Some use cases include tagging containers of retail products moving in and out of warehouses, and tagging baggage being transferred between aircraft and transported within airports. Other use cases include tracking or transmitting environmental data such as temperature, proximity, pressure, or light levels collected by a sensor.Due to the limited power available for processing incoming requests, AMP devices could use a backscatter bit transfer layer (PHY) to initiate communications, but ensuring security in doing so is a difficult design problem. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1A is a block diagram of an exemplary wireless network configured with RF band arrangements for downlink and uplink transmissions between a powered wireless device and an AMP device according to various embodiments. Fig. Figure 1B is a block diagram of an exemplary wireless network configured for an AMP device to generate a backscattered signal using a spreading code to initiate secure communications with a powered wireless device, according to some embodiments. Fig. Figure 2 is a flowchart of an exemplary procedure for initiating secure communication through an AMP device using wireless backscattering according to some embodiments. Fig. 3A and Fig. Figure 3B shows flowcharts of an exemplary procedure for securing a transaction initiated by an AMP device using wireless backscattering, according to some embodiments. Fig. Figure 4 is a flowchart of an exemplary method for initiating secure communication through an AMP device using wireless backscattering according to at least one embodiment. Fig. 5 is a flowchart of a procedure that illustrates the exemplary procedure of Fig. 4 explained from the perspective of a powered wireless device according to at least one embodiment. Fig.Figure 6 is a simplified block diagram of an exemplary wireless device, which may represent any of the powered wireless device or wireless client devices discussed herein according to aspects of the disclosure. DETAILED DESCRIPTION

[0003] The following description details numerous specific aspects, such as exemplary systems, devices, components, methods, and so on, to provide a sufficient understanding of various embodiments for initiating secure communications through an ambient power device (AMP device) using wireless backscattering. Some wireless AMP devices, such as wireless AMP clients, are simple wireless devices that require little processing power and memory and can therefore operate with low power consumption. These AMP devices harvest energy from the environment through energy harvesting (or energy scavenging), which is sufficient for short-term, reduced processing. For example, AMP devices might transmit an identifier (ID) and / or other data collected by or coupled to a sensor on the AMP device.Powered wireless devices, such as routers, access points, powered client devices, etc., can be referenced within mesh networks in this way, since, unlike AMP devices which do not receive continuous external power, these devices receive continuous external power.

[0004] Due to the limited power available for receiving and processing incoming requests and processing and transmitting outgoing responses, communication sessions with wireless AMP devices can be initiated and conducted using wireless backscattering, for example, when the AMP devices are operating in a responder mode as soon as sufficient radio frequency (RF) energy reaches them. Such wireless communication sessions with AMP devices are often unsecured and / or involve technical difficulties, such as ensuring that the AMP devices have sufficient power to both initiate secure communications and transmit enough data to provide necessary information (e.g., from a coupled sensor or similar device).Furthermore, establishing and maintaining an encrypted communication session may require each device participating in the encrypted communication session to maintain constant communication. This type of constant communication is not always possible or feasible for an AMP device.

[0005] Furthermore, typical communication in a WLAN between wireless clients and powered wireless devices requires, in addition to encrypting data exchanged between the wireless AMP clients and powered wireless devices (e.g., once the secure wireless communication session is established), comprehensive handshake protocols to ensure the authentication and verification of connected devices (e.g., to establish a secure network or a secure wireless communication session). For example, many encryption methods may require two devices to exchange multiple data frames to authorize each device, then multiple frames to establish encryption (e.g., to determine respective encryption keys), and then one or more frames to transmit and receive encrypted data.These more comprehensive, protocol-based authentication methods are incompatible with the low-power AMP devices due to the performance requirements. Without encryption, AMP devices are often impractical because of the risk of unencrypted data being transmitted and received, risks that are increasingly relevant in the context of Internet of Things (IoT) devices.

[0006] Aspects of the present disclosure address these and other shortcomings with known approaches for deploying AMP devices in WLAN-based systems by providing methods for AMP devices configured to initiate a secure wireless communication session using wireless backscattering, according to various embodiments. For example, in some embodiments, an AMP device transmits an initialization request frame in a backscattered signal with a predetermined bit pattern using a specific spreading code. Since many AMP devices may attempt to initiate such communication with a powered wireless device, the spreading code can be a gold or other code suitable for correlating energy to distinguish spreading spectra from one another, e.g.,to distinguish between AMP device transmissions over the same frequency band. In embodiments, the present disclosure provides various methods and systems in which an AMP device can initiate a wireless communication session with a powered wireless device via a minimal exchange of data exchange frames such that the wireless communication session, which may hereinafter be referred to as a secure wireless communication session, is also secured, e.g., by authentication and / or encryption.

[0007] In some embodiments, a method comprises an ambient power device (AMP device) that absorbs ambient energy and backscatters radio frequency (RF) energy in a wireless signal received by at least one powered wireless device or wireless helper device, the latter being an access point device (AP device), a beacon device, or the like. The method comprises the AMP device causing an initialization request frame to be transmitted within a backscattered signal to the powered wireless device using a first spreading code. The first spreading code may encode a predetermined bit pattern detectable by the powered wireless device and an identifier (ID) of the AMP device.The method involves the AMP device receiving an ID request frame from the powered wireless device in response to the powered wireless device detecting the initialization request frame and recognizing the AMP device's ID. The ID request frame can then trigger the AMP device to attempt to initiate an encrypted wireless communication session with the powered wireless device.

[0008] In corresponding embodiments from the perspective of a powered wireless device, a method may include the at least periodic computation of channel state information (CSI) data within wireless signals received within a local environment by a powered wireless device, although received signal strength indicator (RSSI) data may also be used together with CSI data. The method may include the powered wireless device spreading the CSI data at a predetermined chip rate to detect a bit pattern. The method may include determining that the bit pattern includes an initial pattern of an initialization request frame received by an ambient power device (AMP device).The method may include the powered wireless device detecting an identifier (ID) of the AMP device that follows the initial pattern. The method may also include transmitting an ID request framework to the AMP device in response to the detection of the AMP device's ID, in order to initiate an attempt to establish an encrypted wireless communication session with the AMP device.

[0009] In some embodiments, once the ID request frame is received and responded to, the AMP device can retrieve a spread start value from the ID request frame and use this spread start value to generate a second spread code specific to the AMP device. This allows the powered wireless device and the AMP device to communicate more securely using a device-specific spread code and to communicate more efficiently by focusing communication using this device-specific spread code, as opposed to using the original spread code that AMP devices can generally use in initialization request frames.Furthermore, the powered wireless device is able to concentrate additional wireless RF power on the specific AMP with which it communicates, to ensure that the AMP device has sufficient power to complete the initiation and execution of the secure wireless communication session, as will be discussed later.

[0010] Among the advantages of the present disclosure is the ability of an AMP device to initiate (and maintain) secure communication with a powered wireless device using wireless backscattering, even though the AMP devices tend to operate infrequently, at low power, and with minimal stored data. Initiating and maintaining such a secure wireless communication session can also occur when the AMP device is located in the same location as many other AMP devices also attempting to communicate with the single powered wireless device. Further advantages for the person skilled in the art in the art in WLAN-related systems for collecting and tracking data that employ AMP devices are discussed in more detail below.

[0011] Fig.Figure 1A is a block diagram of an exemplary wireless network 100A configured with RF band arrangements for downlink (DL) and uplink (UL) transmissions between a powered wireless device 110 and an AMP device 120, such as a wireless AMP client device, according to various embodiments. In some embodiments, the powered wireless device 110 is an access point, router, wireless hub, mobile hotspot device, wireless base station (or cellular base station), client device, or other externally powered device. In some embodiments, the powered wireless device 110 can be externally powered by DC voltage sources and / or AC voltage sources.For example, the powered wireless device 110 can be powered externally by a DC power source, such as a battery (e.g., a laptop or mobile phone battery). In another example, the powered wireless device 110 can be powered externally by an AC power source, such as a wall outlet or building electrical supply. In various embodiments, the AMP device 120 is a radio identification transponder, a low-power wireless client device, or an AMP station (STA). As illustrated, the wireless network 100A can include a second powered wireless device 115, a data storage device 125, and a non-RF-related power source 140.

[0012] In some embodiments, the powered wireless device 110 communicates with a network server 130 to upload data to a cloud. In some embodiments, the network server 130 may be a WLAN server. In these embodiments, the network server 130 includes or is coupled to a data storage device 125 of volatile and / or non-volatile memory, e.g., within a cloud-based storage system located in a local cloud, edge cloud, or the like. In this way, data / information collected by the powered wireless device 110 can be stored by the network server 130 in the data storage device 125, with the data optionally being indexed against respective AMP devices 120, e.g., in a database or the like.In various embodiments, the collected and stored data or information includes an identifier and / or location of the AMP device 120, temperature data, humidity data, pressure data, fill level data (e.g., the fill level of a fluid or gas within a container), and / or other data associated with the environment of the AMP device 120. In some embodiments, the data or information is a log or array of information comprising a data history of the AMP device 120, which includes environmental data or information collected over time. The sensor-related data can be acquired by a sensor 122 (or multiple sensors) that is (or are) contained in or coupled to the AMP device 120.

[0013] In some embodiments, the network server 130 can perform one or more authentication operations on behalf of the powered wireless device 110. The network server 130 can determine whether the powered wireless device 110 is authorized to communicate with the AMP device 120. If the powered wireless device 110 is authorized to communicate with the AMP device 120, the network server 130 can provide the powered wireless device 110 with communication parameters for communication between the powered wireless device 110 and the AMP device 120.In some embodiments, the communication parameters may include one or more authentication and key management parameters (AKM parameters), an encryption key, temporary secrets, or other indicators that cause the powered wireless device 110 to initiate an encrypted wireless communication session with the AMP device 120.

[0014] In some embodiments, the network server 130 determines whether the powered wireless device 110 is authorized to communicate with the AMP device 120 based on an ID of the AMP device 120 (e.g., an AMP ID) and an ID assigned to the powered wireless device 110 (e.g., a user ID). For example, the powered wireless device 110 may be forwarded by the AMP device 120 to the network server 130 (e.g., using a network address such as a URL) when the powered wireless device 110 initiates a procedure to establish an encrypted wireless communication session with the AMP device 120. The powered wireless device 110 may request authorization to communicate with the AMP device 120 from the network server 130.When the network server 130 determines that the powered wireless device 110 is authorized to communicate with the AMP device 120, the network server 130 can provide the powered wireless device 110 with one or more AKM parameters, an encryption key, and / or a temporary secret. The temporary secret can be used by the powered wireless device 110 to generate the one or more AKM parameters and / or an encryption key, although in some embodiments the encryption key is transmitted directly to the powered wireless device in a secure internet session.

[0015] In many embodiments, one or more powered wireless devices 110 and many wireless client devices, which are AMP devices 120, are present, as disclosed herein. AMP devices are powered by absorbing energy from RF signals (e.g., RF-related power sources) and / or from non-RF-related power sources 140 (e.g., by the AMP device 120 absorbing ambient energy). In various embodiments, the absorbed energy originates from RF-related power sources, either in-band RF power sources (e.g., within the RF band that is also used for downlink / uplink (DL / UL) transmissions) or out-of-band RF power sources (e.g., downlink (DL) transmissions and uplink (UL) transmissions take place in RF bands other than the RF band used for energy absorption).In additional embodiments, non-RF-related power sources include solar or photovoltaic cells (converting sunlight from the environment into electrical current), thermoelectric generators (converting temperature gradients into electrical current), vibration energy capture using piezoelectric, electrostatic, and electromagnetic transducers (converting mechanical vibrations from the environment into electrical current), miniature wind turbines (converting wind energy from the environment into electrical current), differential pressure energy capture, dynamos or portable harvesters (converting the movements of people or animals into electrical energy), and other such energy capture mechanisms. In some embodiments, the AMP device 120 can capture ambient energy using one or more collector circuits (e.g., AMP collector circuits).The collective circuits can include circuit components that can absorb any of the above-mentioned types of energy (e.g., the collective circuit can be configured to absorb ambient energy from one or more of the above-mentioned sources).

[0016] With further reference to Fig. In at least one embodiment, the powered wireless device 110 transmits a first wireless signal (101), which is a DL transmission, over a first RF band to the AMP device 120. In some embodiments, the first wireless signal comprises a data packet (or frame) requesting information from the AMP device 120. The AMP device 120 can receive the first wireless signal and analyze the data packet to determine the requested information.

[0017] In some embodiments, the powered wireless device 110 does not transmit the power-providing RF signal. For example, in other embodiments, the wireless network 100A further comprises a second powered wireless device 115 and / or non-RF-related power sources 140 that provide RF power or non-RF power, respectively, and from which the AMP device 120 draws ambient power (e.g., from power sources other than the powered wireless device 110, which is associated with the DL / UL transmissions). In at least some embodiments, the second powered wireless device 115 transmits a power-providing RF signal (104) to the wireless client device, from which the wireless client device draws power. In further embodiments, the power-providing signals (101) or (103) are combined with the power-providing RF signal (104).Furthermore, either only the non-HF-related energy intake or the non-HF-related energy intake in combination with the HF-related energy intake can be used.

[0018] In embodiments, the AMP device 120 transmits a second wireless signal (102), which is a UL transmission, over a second RF band to the powered wireless device 110 with a data packet (or data frame) containing the requested information. In this way, the requested information or data (discussed previously) can be requested from and received by the AMP device 120 through the exchange of data packets (or data frames). In various embodiments, the powered wireless device 110 (and / or the second powered wireless device 115) generates the first wireless signal (or the powered RF signal (4)) using technologies such as Wi-Fi®, Bluetooth®, Bluetooth® Low Energy, Ultra-Wideband (UWB), Z-wave™, Zigbee®, LoRa™, Wi-SUN®, or another radio protocol.In various embodiments, the AMP device 120 generates the second wireless signal using technologies such as Wi-Fi®, Bluetooth®, Bluetooth® Low Energy, Ultra-Wideband (UWB), Z-wave™, Zigbee®, LoRa™, Wi-SUN® or another radio protocol.

[0019] In some embodiments, the first RF band for DL ​​transmission differs from the second RF band used for UL transmission. In some embodiments, the second RF band is in a lower frequency range than the first RF band, for example, because less power is consumed at lower frequencies. Lower frequencies also result in lower path losses compared to higher frequencies, and at the same power, wireless signals can be adequately received and decoded at greater distances and propagate better through or around obstacles compared to higher frequencies. Furthermore, the RF and circuit design can be far less complex at lower frequencies compared to those designed for higher-frequency operation, thus keeping the cost of the AMP 120 devices low.

[0020] In some embodiments, the second RF band is in a higher frequency range than the first RF band. For example, wider channel bandwidths are used when operating at higher frequencies, which in turn allows for the transmission of the same number of user bytes and earlier termination. The AMP device 120 can then receive and / or transmit in a shorter time, thus saving power and providing a separate power consumption advantage. Accordingly, the use of a higher or lower frequency range for UL transmission (compared to DL transmission) may involve a cost-benefit analysis, weighing the advantages of each frequency range.

[0021] In other embodiments, the first RF band is the same as the second RF band, but the DL and UL transmissions occur over different frequencies with a considerable separation (e.g., several hundred megahertz (MHz) within the same RF band). In this way, both the technology and the RF bands (or RF frequencies) can differ between the DL / UL transmissions, allowing the AMP 120 devices to operate at lower power while avoiding frequency conflicts between the DL and UL transmissions.

[0022] In various embodiments, the first wireless signal (101), transmitted, for example, in the first RF band, is also a powered RF signal, represented by thick directional arrows, from which the AMP device 120 draws ambient power. In similar embodiments, the powered wireless device 110 instead transmits a separate powered RF signal (103) to the AMP device 120; however, this separate powered RF signal (103) is also located within the first RF band and is not necessarily the same as the first wireless signal (101), although they may be close in frequency. In alternative embodiments, the separate powered RF signal (103) is transmitted over the second RF band, e.g., the UL transmission band, or is transmitted over a completely different, third RF band.Accordingly, in different embodiments, the power-supplying RF signal (103) is transmitted via the first RF band, the second RF band, or the third RF band. For example, in some embodiments, the first RF band is, for instance, 5.0 gigahertz (GHz), the second RF band may be 2.4 GHz, and the third RF band 5.0 or 6.0 GHz, the third RF band also being available for use by the powered wireless device 110 to communicate with other mobile stations (STA).

[0023] Data can be transmitted between the powered wireless device 110 and the AMP device 120 as frames in a request-response protocol. The request-response protocol can also be based on a secret shared between the network server 130 and the AMP device 120, as described above. The secret can be stored in the data storage 125 (or at another secure location) and programmed into the AMP device 120 during manufacturing or prior to deployment within an operational network.

[0024] In some embodiments, the request and response protocol between the powered wireless device 110 and the AMP device 120 is compatible with the Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) network protocol. In some embodiments, the request and response protocol between the powered wireless device 110 and the AMP device 120 is compatible with the Request-to-Send / Clear-to-Send (RTS / CTS) network protocol. In some embodiments, the request and response protocol between the powered wireless device 110 and the AMP device 120 is compatible with backscattering, which is discussed in more detail herein. Table 1 First field Second field Third field Fourth field Fifth field Recipient ID Sender ID Frame type Usage data Frame test data

[0025] Frames (or packets) may contain information divided into at least five fields, as shown in Table 1, although not every frame needs to contain every field, and these fields may be in a different order in some frames depending on the implementation and application. Furthermore, in some of the latter embodiments discussed herein, the AMP ID is encrypted or subject to a hash algorithm within the payload to maintain privacy. In various embodiments, the first field of the frame contains the receiver ID (e.g., the ID of the powered wireless device 110 or the ID of the AMP device 120). In some embodiments, the receiver ID is the media access control (MAC) address of the receiver device, also referred to herein as a MAC destination address. In alternative embodiments, the receiver ID is a unique, pre-assigned ID (e.g.,(assigned during manufacturing or prior to use within an operational network). For example, in some embodiments, the power received by the AMP device 120 is insufficient to perform program operations in non-volatile memory, and the AMP device 120 may have a unique ID (e.g., AMP ID) that is programmed in non-volatile memory of the AMP device 120 during an initial factory setting with external power. Some request frames received at the AMP device 120 may contain the ID of the AMP device 120 in the first field. Some responses received at the powered wireless device 110 may contain the ID of the powered wireless device 110 in the first field.

[0026] In some embodiments, the receiver ID identifies a specific subset of receiver devices (e.g., multiple AMP devices 120). For example, the receiver ID may be a subset of MAC addresses (e.g., a group address such as a MAC multicast address) corresponding to the specific subset of AMP devices 120. In some embodiments, the receiver ID identifies any receiver device (e.g., any AMP device 120) within a radio link range of a transmitter device (e.g., the powered wireless device 110). For example, the receiver ID may be a MAC broadcast address such as FF:FF:FF:FF:FF:FF.

[0027] In various embodiments, the second field of the frame contains the transmitter ID (e.g., the ID of the powered wireless device 110 or the ID of the AMP device 120, commonly referred to as a transmitting device). In various embodiments, the third field of the frame contains the frame type, which can identify the frame type, e.g., initialization request frame, ID response frame, data request frame, data response frame. In some embodiments, the frame type identified in the third field is based on or defines information contained in the payload of the fourth field.

[0028] In various embodiments, the fourth field of the frame contains the payload, which may include frame exchange parameters, data, commands, AKM parameters (e.g., Simultaneous Authentication of Equals (SAE)), encryption suites (e.g., Advanced Encryption Standard (AES), such as AES 128-bit (AES128)), physical layer parameters (PHY parameters) to control frame transmission and reduce conflicts, a random value, a nonce value, and session information (e.g., a session number). The random and / or nonce values ​​can be used to prevent man-in-the-middle and / or replay attacks. In some embodiments, parts of the payload may be secured, for example, by encryption or hashing, as will be discussed in more detail depending on the embodiment.

[0029] In some embodiments, the AKM parameters may contain one or more cryptographic parameters. In some embodiments, the AKM parameters include a scalar value, which may be an input to an encryption algorithm, and an element value, which may be an output of the encryption algorithm. In some embodiments, the encryption algorithm is associated with an elliptic curve, where the scalar value denotes a position on the elliptic curve and the element value represents the position on the elliptic curve selected by the scalar value.

[0030] In various embodiments, the fifth field of the frame contains frame verification data, although not every frame or packet needs to contain frame verification data. The frame verification data can be data that can be used by the receiving device (e.g., the powered wireless device 110 or the AMP device 120) to verify that the frame (or packet) was received without errors or modifications. In some embodiments, the frame verification data can include unsecured error checking data, such as checksum data or cyclic redundancy check (CRC) data, or secured (e.g., encrypted or hashed) error checking data, such as message integrity code (MIC) data, depending on the application and the network link status.

[0031] Fig. Figure 1B is a block diagram of an example wireless network 100B, designed for an AMP device such as the AMP device 120. Fig.1A, is configured to generate a backscattered signal using a spreading code to initiate secure communications with a powered wireless device, according to some embodiments. For example, in some embodiments of the AMP device 120, the powered wireless device 110 can provide power in a powered RF signal, such as the powered RF signal 101 and / or 103. Furthermore, a wireless helper device 150 (such as the second powered wireless device 115 in Fig.1A) also provide power in a powered RF signal, such as the powered RF signal 104. In some embodiments, the one or more powered RF signals can be directed at the AMP device 120 and provide RF energy or power to the AMP device 120, which can then reflect and / or absorb the powered RF signal in a so-called backscattered signal 160. In this way, the AMP device 120 can function as a transponder. The one or more powered RF signals can also provide the AMP device 120 with at least partial power sufficient to process data in order to establish a secure wireless communication session with the powered wireless device 110, as explained above and discussed in more detail below.

[0032] In some embodiments, the AMP device 120 can encode a series of bits within the backscattered signal 160, e.g., digital ones and zeros. For example, the AMP device 120 can determine the impedance of an antenna (see Fig.6) at a known rate (e.g., 100 Hz, 200 Hz, or the like), also known as the chip rate, to transmit a binary sequence by reflecting and absorbing wireless signals. For example, the AMP device 120 can maximize the reflection of RF energy, thereby displaying a one, or maximize the absorption of RF energy (and thus minimize reflection), thereby displaying, for example, a zero. In some embodiments, the AMP device 120 uses a spreading code, both of which are known to the powered wireless device 110, to communicate with the powered wireless device 110 using a spreading spectrum within the backscattered signal 160.Furthermore, the spreading code can also be used by other AMP devices at the chip rate in the area of ​​the initialization contact with the powered wireless device. In various embodiments, the spreading code includes, for example, M-sequences, Kasami sequences, Barker codes, Walsh codes, pseudonoise sequences, Zadoff-Chu sequences, or Gold codes.

[0033] In some implementations, the chip rate can be viewed as the number of chips transmitted per second in a spread-spectrum communication system, measured, for example, in chips per second (CPS). Thus, in spread-spectrum systems like CDMA (Code Division Multiple Access), the data signal (i.e., the backscattered signal 160) is spread over a wider bandwidth using a spreading code. Each bit of the original data can be replaced by a sequence of smaller units called chips. Chips are the elements of the spreading code, and their duration is shorter than that of the original data bits. The chip rate can therefore be higher than the data bit rate. For example, the chip rate can be the data rate multiplied by a spreading factor of the spreading code.

[0034] Fig.Figure 2 is a flowchart of an exemplary method 200 for initiating secure communication through an AMP device using wireless backscattering according to some embodiments. The method 200 can be performed by processing logic that may include hardware (e.g., a processing device, circuit components, dedicated logic, programmable logic, microcode, the hardware of a device, an integrated circuit, etc.), software (e.g., instructions run or executed in a processing device), or a combination thereof. In some embodiments, the method 200 is performed by processing logic of the powered wireless device 110 and / or by a representative AMP device 120 ( Fig.1A-1B) are carried out depending on the process. A specific sequence or order is shown, but the order of the processes can be modified unless otherwise specified. Therefore, the illustrated embodiments should be considered examples only, and the illustrated processes can also be carried out in a different order, and some processes can also be carried out in parallel. In addition, one or more processes may be omitted in different embodiments. Thus, not all processes are required in every embodiment. Other process sequences are possible.

[0035] In process 205, the AMP device 120 transmits an initialization request frame 201 in a backscattered signal with a predetermined bit pattern using an initial spreading code. The predetermined bit pattern can be 0xAC53, which is merely an example. In some embodiments, the predetermined bit pattern is a known initial pattern and thus detectable by the powered wireless device 110. In some embodiments, the initial pattern is followed by an identifier (ID) of the AMP device 120 within the initialization request frame 201. Regardless of which spreading code is used (see Fig.1B), the length of the spreading code should be sufficiently long so that the powered wireless device 110 can reliably detect the initialization request frame 201 and detect multiple AMP devices transmitting initialization request frames at approximately the same time. Thus, the length of the spreading code that generates the initial pattern can depend on the application and on how many AMP devices are expected to be near the powered wireless device 110.

[0036] In process 210, the powered wireless device 110 spreads CSI data at a predetermined chip rate to detect the predetermined bit pattern within the initialization requirement frame 201. In some embodiments, the spreading includes analyzing RSSI data to aid in bit pattern detection. Thus, for example, the CSI data may also include received signal strength indicator (RSSI) data, and process 200 further includes using the RSSI data to spread the CSI data to detect the bit pattern.

[0037] In process 215, the powered wireless device 110 determines whether the predetermined bit pattern contains a known initial pattern of the initialization request frame 201. For example, the powered wireless device 110 may store an initial pattern to be used to detect incoming initialization request frames. If the initial pattern is not detected, process 200 returns to process 210 and continues the unspreading of CSI data (and optionally analyzes RSSI data) to determine whether bit patterns are detected that may be arriving in any number of initialization request frames from multiple AMP devices.

[0038] In process 220, the powered wireless device 110, in response to the detection of the initial pattern, determines whether it recognizes the identifier (ID) of the AMP device 120 following the initial pattern. If not, process 200 returns to process 210 and continues the CSI data decongestion.

[0039] In process 222, the powered wireless device 110 can optionally transmit a request to the wireless helper device 150 in response to the recognition of the ID of the AMP device 120 in process 220, causing the wireless helper device 150 to increase its transmit power directed to the AMP device 120.

[0040] In process 224, in response to the recognition of the ID of the AMP device 120 in process 220, the powered wireless device 100 can additionally or instead of process 222 adjust the direction of an antenna of the powered wireless device 110 so that it is aligned with the AMP device 120. Such beamforming allows the RF energy of one or more powered RF signals to be better directed at the AMP device 120, thereby improving the subsequent processes for establishing and terminating the secure wireless communication session.

[0041] In process 225, the powered wireless device 110 generates and transmits an ID request frame 202 to the AMP device 120 to initiate an attempt to initiate an encrypted wireless communication session with the AMP device.

[0042] In process 230, the AMP device 120 determines whether it has received an ID request frame 202. Thus, the AMP device 120 monitors, for example, the wirelessly received RF signals for such an ID request frame 202.

[0043] In process 235, the AMP device 120 waits for a random delay time in response to the ID request frame 202 not being received. In some embodiments, the random delay time is a pseudorandom delay time, such as that generated by the AMP device 120. Furthermore, in process 200, the process returns to process 205, in which the AMP device 120, after waiting for the random delay time, causes the initialization request frame 201 to be retransmitted to the powered wireless device 110. Since it is necessary to attempt to be recognized again by the powered wireless device 110, the AMP device 120 may thus attempt to avoid an overlap with other communication signals (e.g.,to avoid (from other AMP devices and / or powered wireless devices) by retransmitting the Initialization Request Framework 201 at a random time.

[0044] In operation 240, upon receiving the ID Request Frame 202, the AMP device 120 determines whether a checksum value contained within the ID Request Frame 202 is correct (see, for example, frame check data in Table 1). If it is incorrect, operation 200 returns to operation 205 to retransmit the Initialization Request Frame 201. Other checks (e.g., authentication) are also possible here, such as decrypting or hashing data contained in the ID Request Frame payload to compare it against known values ​​(e.g., plaintext values ​​or previously hashed values).

[0045] In operation 245, the AMP device, in response to receiving a correct checksum value in operation 240, retrieves a spread start value from the ID request frame 202. For example, the ID request frame 202 can contain the spread start value from which the AMP device determines a device-specific spread code. A spread start value can be, for example, an initial value or a set of values ​​used to generate a pseudorandom sequence, which in turn is used as the spread code in spread spectrum communication.

[0046] For example, the spread start value can be used in deterministic algorithms that generate the spread codes. In various embodiments, spread codes are derived from pseudorandom sequences that appear random but are generated by deterministic processes. The spread start serves as the starting point for these processes. One method for generating pseudorandom sequences is the use of linear feedback shift registers (LFSRs), although other processes are also possible. The spread start initializes the LFSR, which then cycles through a sequence of states to generate the spread code. The use of a spread start ensures that the pseudorandom sequence (spread code) can be accurately reproduced by both the sender and the receiver (e.g., the AMP device 120 and the powered wireless device 110, respectively), provided that both use the same start and generation algorithm.

[0047] In some embodiments, the device-specific spreading code is shorter than the original spreading code. In other embodiments, the device-specific spreading code is transmitted at the predetermined chip rate or eliminates the spreading spectrum transmission entirely. For example, by shortening the spreading code or eliminating the spreading spectrum transmission, the AMP device 120 can completely reduce power consumption while still enabling direct communication with the powered wireless device 110, which has recognized the AMP ID of the AMP device 120.

[0048] During operation 250, the AMP device 120 generates a second spreading code specific to the AMP device 120 using the spreading start value, e.g., a device-specific spreading code for use in further communication with the powered wireless device 110 during the secure wireless communication session.

[0049] In process 255, the AMP device 120 uses the second spreading code (e.g., the device-specific spreading code) to generate bitstreams that are contained in future frames, which are transmitted to the powered wireless device, with reference to the Fig. 3A-3B will be discussed in more detail. Such future frames may include the ID of the AMP device 120 at the beginning of the frame, so that it can be detected by the powered wireless device 110 and correlated with the correct AMP device.

[0050] In process 260, the powered wireless device spreads 110 CSI data at a second or updated predetermined chip rate to detect the AMP ID in the bit pattern and decode these future frames, which, with reference to the Fig. 3A-3B will be discussed in more detail.

[0051] Fig. 3A and Fig.Figure 3B shows flowcharts of an exemplary method 300 for securing a transaction initiated by an AMP device using wireless backscattering, according to some embodiments. The method 300 can be performed by processing logic that may include hardware (e.g., a processing device, circuit components, dedicated logic, programmable logic, microcode, the hardware of a device, an integrated circuit, etc.), software (e.g., instructions run or executed in a processing device), or a combination thereof. In some embodiments, the method 300 is performed by processing logic of the AMP device 110, which absorbs ambient energy, and one or more powered wireless devices ( Fig. 1A and Fig.1C). A specific sequence or order is shown; however, the order of the processes can be modified unless otherwise specified. Therefore, the illustrated embodiments should be considered examples only, and the illustrated processes can also be carried out in a different order, and some processes can also be carried out in parallel. In addition, one or more processes may be omitted in different embodiments. Thus, not all processes are required in every embodiment. Other process sequences are possible.

[0052] In process 305, the AMP device determines a secret that is shared with the powered wireless device 110.

[0053] In operation 307, the AMP device 120 determines one or more initial authentication and key management parameters (AKM parameters), e.g., using the shared secret.

[0054] In operation 310, the AMP device 120 generates and transmits an ID response frame 301 using the (in operation 250 of Fig.2 generated) second spreading codes to the powered wireless device 110. In some embodiments, the ID response frame 301 includes the ID of the AMP device, the session ID, and one or more first AKM parameters used to mutually authenticate the powered wireless device 110 and the AMP device 120 and to generate an encryption key to initiate an encrypted wireless communication session. In some embodiments, the AMP device 120 causes its ID to be listed first in the ID response frame 301 to signal to the powered wireless device 110 that the ID response frame 301 originates from the AMP device 120. The ID response frame 301 may also include one or more frame exchange parameters and a checksum value.

[0055] In an alternative embodiment, the AMP device 120 in operation 310 in the ID response frame 301 comprises a first set of plaintext fields and a first hash value generated from a combination of content from the first set of plaintext fields and an identifier of the AMP device (e.g., the AMP ID). In embodiments, the first set of plaintext fields includes, for example, a session identifier, one or more frame exchange parameters, and optionally a random value and / or a nonce value. A combination of other values ​​instead of these is also possible, and therefore the specific values ​​listed here for different frames are only examples.

[0056] In operation 315, the powered wireless device 110 receives the ID response frame 301 from the AMP device 120, e.g. by performing operation 260 of Fig.2. For example, the powered wireless device 110 can spread the CSI data at an updated chip rate corresponding to the device-specific spreading code to detect a second bit pattern encoded with the ID response frame 301 received by the AMP device 120. In embodiments, the ID response frame 301 includes an ID of the AMP device 120, positioned first, the session ID, and one or more initial AKM parameters. Furthermore, in response to the detection of the ID of the AMP device 120, the powered wireless device 100 can decode a remainder of the ID response frame received by the AMP device 120 to obtain the initial AKM parameters used to initiate the encrypted wireless communication session with the AMP device 120.

[0057] In operation 320, the powered wireless device 110 verifies whether the checksum value of the received ID response frame 301 is correct. If the error check value is incorrect, operation 300 terminates; for example, the powered wireless device 110 returns to operation 315 and continues monitoring for an ID response frame. If the error check value is correct, the powered wireless device 110 proceeds to operation 325.

[0058] In the alternative embodiment, during operation 320, the powered wireless device 110 generates a second hash value from a combination of the contents of the plaintext fields and the ID of the AMP device, which is retrieved from a memory of the powered wireless device 110. Furthermore, during operation 320, the powered wireless device 110 determines whether the first hash value matches the second hash value. Upon determining that the first hash value does not match the second hash value, the powered wireless device 110 returns to operation 315 and continues listening for an ID response frame. Upon determining that the first hash value matches the second hash value, the powered wireless device 110 proceeds to operation 325.This alternative embodiment of using hash values ​​may be most practical when there are only a few AMP devices (and thus the powered wireless device 110 is subject to limitations regarding the number of hash operations that must be performed to verify the authorization of access to these AMP devices).

[0059] In operation 325, the powered wireless device 110 generates second AKM parameters in response to the determination in operation 320 that the checksum value is correct or that the first hash value matches the second hash value (in the alternative embodiment). For example, the powered wireless device 120 can retrieve a secret shared with the AMP device 120 from memory, select an AKM procedure to apply, and, using the secret and the AKM procedure, generate one or more first AKM parameters. For example, the secret can be stored in memory (e.g., in a data structure, as an entry in a lookup table, matrix, linked list, data file, or the like) based on the identifier of the AMP device 120.In another example, a first secret can be stored (and used) with respect to a first AMP device or multiple first AMP devices 120, and a second secret can be stored (and used) with respect to a second AMP device or multiple second AMP devices 120.

[0060] In various embodiments, AKM methods include one or more of a password-based challenge-response method, a simultaneous authentication of equals (SAE) method, a public-private key trust method (using, for example, security certificates), or the like. In some embodiments, the AKM method is based on an encryption block, where data is encrypted in blocks of a fixed size (e.g., 64 bits, 128 bits, etc.). Plaintext can be divided into blocks, and each block is encrypted independently using the same encryption key, with the encryption of each block potentially dependent on the encryption of a previous block. In alternative embodiments, the AKM method is based on an encryption stream, where data is encrypted bitwise. Plaintext can be encrypted with a pseudorandom data stream of bits (e.g.,encrypted text) can be combined using a bitwise exclusive-OR (XOR) function.

[0061] In Operation 330, the powered wireless device 110 determines a session key from the first AKM parameters and the second AKM parameters. The session key can, for example, be a Ksae derived during a SAE authentication process, where, for instance, both the powered wireless device 110 and the AMP device 120 prove to each other that they both know the shared secret without actually exchanging the shared secret. Other key generation procedures are also possible. Furthermore, in Operation 330, the powered wireless device 110 can generate an encryption key and an integrity key using the session key.

[0062] In Operation 335, the powered wireless device 110 generates and transmits a data request frame 302 to the AMP device 120 to obtain data requested by the AMP device 120, such as sensor or environmental data, as previously discussed. Additionally, as part of Operation 335, in some embodiments, the powered wireless device 110 encrypts an instruction (e.g., a data request instruction) using the encryption key and determines a first message integrity code (MIC) using the integrity key. In some embodiments, the data request frame 302 includes one or more frame exchange parameters, one or more second AKM parameters, the first MIC, and the encrypted instruction. The data request frame 302 may optionally also include the session ID and a nonce value.In some embodiments, the frame exchange parameters include an encryption type (e.g., an encryption suite). The encryption type may be associated with an AKM method. In some embodiments, the encryption type is associated with an encryption algorithm (as described above). As described above, the AMP device 120 selects the AKM method. In some embodiments, the powered wireless device 110 may select the AKM method.

[0063] In operation 340, the AMP device 120 receives the data request frame 302, which is transmitted by the powered wireless device 110. In some embodiments, the data request frame 302 includes one or more second AKM parameters generated by the network server, a first message integrity code (MIC) determined using an integrity key generated from a session key received from the network server, and an encrypted command determined using an encryption key generated from the session key.

[0064] With further reference to Fig.In Operation 3B, the AMP device 120 determines an encryption key and an integrity key using one or more of the first AKM parameters and one or more of the second AKM parameters. Just as, for example, the powered wireless device 110 does in Operation 330, the AMP device 120, now having the second AKM parameters from the data request framework 302, can determine the session key (or Ksae). Furthermore, the powered wireless device 110 can generate the encryption key and the integrity key in Operation 360 using the session key.

[0065] During process 365, the AMP device 120 determines whether the first MIC is verified with the integrity key. In response to the first MIC not being verified, the AMP device 120 terminates a procedure to establish an encrypted wireless communication session with the powered wireless device 110.

[0066] In process 370, in response to the verification of the first MIC, the AMP device 120 uses the encryption key to decrypt the encrypted command in order to generate a decrypted command.

[0067] In operation 375, the AMP device 120 executes the decrypted command to, for example, determine which data is desired and retrieve the desired data or information. In some embodiments, executing the decrypted command includes generating a second MIC using the integrity key and generating encrypted data using the encryption key to encrypt data that includes status and / or environmental data retrieved from a coupled sensor.

[0068] In process 380, the AMP device 120 generates and transmits a data response frame 306 using the second spreading code, which includes the second MIC and the encrypted data. In some embodiments, the data response frame 306 also includes a session ID and optionally a nonce value.

[0069] In operation 385, the powered wireless device 110 receives the data response frame 306 from the AMP device 120, e.g. by performing operation 260 of Fig. 2. For example, the powered wireless device 110 can spread the CSI data at an updated chip rate corresponding to the device-specific spreading code to detect a second bit pattern encoded in the data response frame 306 received by the AMP device 120. In embodiments, the data response frame 306 includes an ID of the AMP device 120, which is positioned first, the session ID, encrypted data, and a second MIC. The powered wireless device 100 can further decode a portion of the data response frame 306 received by the AMP device 120 in response to the detection of its ID, in order to obtain the remainder of the data response frame 306.

[0070] During process 390, the powered wireless device 110 determines whether the second MIC is verified. In response to the second MIC not being verified, the powered wireless device 110 terminates a procedure to establish an encrypted wireless communication session with the AMP device 120.

[0071] In process 395, the powered wireless device decrypts and processes the decrypted data received from the AMP device 120 in response to the verification of the second MIC.

[0072] Fig.Figure 4 is a flowchart of an exemplary method 400 for initiating secure communication through an AMP device using wireless backscattering according to at least one embodiment. The method 400 can be performed by processing logic that may include hardware (e.g., a processing device, circuit components, dedicated logic, programmable logic, microcode, the hardware of a device, an integrated circuit, etc.), software (e.g., instructions run or executed in a processing device), or a combination thereof. In some embodiments, the method 400 is performed by processing logic of the AMP device 120, which absorbs ambient energy ( Fig. 1A and Fig. 1B), carried out. The AMP device 120 can include at least one antenna, which may be coupled to the processing logic, as described in relation to Fig.Section 6 discusses this. A specific sequence or order is shown; however, the order of the processes can be modified unless otherwise specified. Therefore, the illustrated embodiments should be considered examples only, and the illustrated processes can also be carried out in a different order, and some processes can also be carried out in parallel. Furthermore, one or more processes may be omitted in different embodiments. Thus, not all processes are required in every embodiment. Other process sequences are possible.

[0073] In process 410, the processing logic is to cause the at least one antenna to backscatter, e.g., reflect as a backscattered signal, radio frequency (RF) energy received in a wireless signal from at least one powered wireless device or wireless helper device.

[0074] In process 420, the processing logic causes the at least one antenna to transmit an initialization request frame within a backscattered signal to the powered wireless device using a first spreading code. In embodiments, the first spreading code encodes a predetermined bit pattern, recognizable by the powered wireless device, and an identifier (ID) of the wireless device.

[0075] In process 430, the processing logic causes the at least one antenna to receive an ID request frame from the powered wireless device in response to the powered wireless device detecting the initialization request frame and recognizing the ID of the wireless device. In embodiments, the ID request frame triggers an attempt to initiate an encrypted wireless communication session with the powered wireless device.

[0076] Fig. Figure 5 is a flowchart of a procedure 500, which is the exemplary procedure 400 of Fig.4 is explained from the perspective of a powered wireless device according to at least one embodiment. The method 500 can be performed by processing logic that may include hardware (e.g., a processing device, circuit components, dedicated logic, programmable logic, microcode, the hardware of a device, an integrated circuit, etc.), software (e.g., instructions that are run or executed in a processing device), or a combination thereof. In some embodiments, the method 500 is performed by processing logic of the powered wireless device 110 ( Fig. 1A and Fig.1C). A specific sequence or order is shown; however, the order of the processes can be modified unless otherwise specified. Therefore, the illustrated embodiments should be considered examples only, and the illustrated processes can also be carried out in a different order, and some processes can also be carried out in parallel. In addition, one or more processes may be omitted in different embodiments. Thus, not all processes are required in every embodiment. Other process sequences are possible.

[0077] In process 510, the processing logic calculates channel state information data (CSI data) at least periodically within wireless signals received within a local environment.

[0078] In process 520, the processing logic spreads the CSI data at a predetermined chip rate to detect a bit pattern.

[0079] In Operation 530, the processing logic determines that the bit pattern includes an initialization request frame received by an ambient power (AMP) device. In embodiments, the initialization request frame is encoded using a known spreading code at the predetermined chip rate, and Operation 500 further includes using the known spreading code when unspreading the CSI data in Operation 520.

[0080] During process 540, the processing logic detects an identifier (ID) of the AMP device that follows the initial pattern.

[0081] In process 550, the processing logic transmits an ID request framework to the AMP device in response to the detection of the AMP device's ID, in order to initiate an attempt to establish an encrypted wireless communication session with the AMP device.

[0082] Fig.Figure 6 is a simplified block diagram of an exemplary wireless device 600, which may represent any powered wireless device 110 or wireless client devices discussed herein according to aspects of the disclosure. For example, the wireless client devices may include the AMP device 120. In at least some embodiments, the wireless device 600 includes, but is not limited to, a transmitter 602 or TX (e.g., a WLAN transmitter), a receiver 604 or RX (e.g., a receiver 604), and a receiver 604 or RX (e.g., a receiver 604).a WLAN receiver), a communication interface 606, at least one TX antenna 610A coupled to the transmitter 602, at least one RX antenna 610B coupled to the receiver 604, a memory 614, one or more input / output devices (I / O devices) 618 (such as a display screen, a touchscreen, a keyboard, and the like), a processor 620, an AMP assembly 625, and power cells 628. In embodiments, the wireless device 600 comprises two antennas for multiple-input multiple-output (MIMO) operation of a transceiver (which includes, for example, the TX and the RX), which may include circuit components to switch between dual bands, including, for example, the 2.4 GHz and the 5 GHz bands.

[0083] These components can all be coupled to one or more communication buses 630. In some embodiments, at least some of the components of the wireless device 600 are directly connected and are therefore not coupled via the communication bus 630. Thus, the representation of the communication bus 630 is not to be considered necessary or restrictive for at least some of the components of the wireless device 600, which can communicate directly with each other.

[0084] In some embodiments, aspects of the communication interface 606 interact with the processor 620 to perform operations or function as a processing unit of the wireless device 600. In some embodiments, only one antenna and multiplex logic for switching the antenna between TX and RX are present. In some embodiments, the powered wireless device 110 does not have an energy harvester but uses a battery and / or is powered by alternating current (AC).

[0085] In at least some embodiments, the memory 614 includes a data storage for storing instructions executable by the processor 620 and / or data generated by the communication interface 606. In various embodiments, front-end components such as the transmitter 602, the receiver 604, the communication interface 606, and one or more antennas are designed or configured for WLAN and WLAN-based frequency bands, e.g., Wi-Fi®, Bluetooth® (BT), Bluetooth® Low Energy (LBE), Ultra-Wideband (UWB), Z-wave™, Zigbee®, LoRa™, Wireless Smart Utility Network® (Wi-SUN®), or other radio protocols. While some of the protocols may be referred to as Personal Area Network (PAN) technology for simplicity, they are all generally referred to as WLAN technology. Future protocols are also considered.

[0086] In various embodiments, the communication interface 606, e.g., as a front end of the wireless device 600, is integrated into the transmitter 602 and the receiver 604. Depending on instructions from the processor 620, the communication interface 606 may coordinate the requesting / receiving of packets from other wireless devices or packets reflected from objects. The communication interface 606 can also process data symbols received by the receiver 604 in such a way that the processor 620 can further process them, including identifying and analyzing data packets received within the wireless signals. In some embodiments, the transmitter 602, the receiver 604, the communication interface 606, and the antennas 610A and 610B may be referred to herein as a "wireless communication circuit".

[0087] In various embodiments, the AMP collection circuit 625 performs processes disclosed herein to detect electromagnetic or RF signals and non-RF energy of other kinds, e.g., light, temperature gradients, pressure differences, mechanical vibrations, wind energy, and the like, as described with reference to Fig. 1A discussed. As discussed, the AMP harvesting circuit 625, with reference to the harvesting of energy from wireless RF signals, is possibly a multi-band harvester configured to harvest energy from several frequency ranges that define different RF bands. In these embodiments, the AMP harvesting circuit 625 is also configured to store the harvested energy within the energy cells 628, which are then operated as a power source for the wireless device 600.

[0088] It is obvious to those skilled in the art that at least some embodiments can be practically implemented without these specific details. In other cases, well-known components, elements, or methods are not described in detail or are represented by a simple block diagram in order to avoid unnecessarily complicating the understanding of the subject matter described herein. Therefore, the specific details set forth below are purely exemplary. Individual implementations may deviate from these exemplary details and still be considered compatible with the concept of the present embodiments and within their scope of protection.

[0089] References in the description to “an embodiment,” “an exemplary embodiment,” “an exemplary embodiment,” “some embodiments,” or “different embodiments” mean that a particular feature, structure, step, process, or property described in connection with the one or more embodiments is included in at least one embodiment. Furthermore, the terms “an embodiment,” “an exemplary embodiment,” “an exemplary embodiment,” “some embodiments,” and “different embodiments,” when used at different points in the description herein, do not necessarily all refer to the same embodiment (or embodiments).

[0090] The description includes references to the accompanying drawings, which form part of the detailed description. The drawings show representations according to exemplary embodiments. These embodiments, which may also be referred to herein as "examples," are described in such detail that a person skilled in the art is enabled to practically implement the embodiments of the claimed subject matter described herein. The embodiments can be combined, other embodiments can be used, or structural, logical, and electrical modifications can be made without departing from the scope of protection and the concept of the claimed subject matter.It is understood that the embodiments described herein are not intended to restrict the scope of protection of the object, but rather to enable the person skilled in the art to practically implement, manufacture and / or use the object.

[0091] The description includes references to the accompanying drawings, which form part of the detailed description. The drawings show representations according to exemplary embodiments. These embodiments, which may also be referred to herein as "examples," are described in such detail that a person skilled in the art is enabled to practically implement the embodiments of the claimed subject matter described herein. The embodiments can be combined, other embodiments can be used, or structural, logical, and electrical modifications can be made without departing from the scope of protection and the concept of the claimed subject matter.It is understood that the embodiments described herein are not intended to restrict the scope of protection of the object, but rather to enable the person skilled in the art to practically implement, manufacture and / or use the object.

[0092] Certain embodiments can be implemented by firmware instructions stored in a non-volatile, computer-readable medium, such as volatile memory and / or non-volatile storage. These instructions can be used to program and / or configure one or more devices containing processors (e.g., CPUs) or equivalents thereof (e.g., processing cores, processing engines, microcontrollers, and the like) such that, when executed by the one or more processors or their equivalents, the instructions cause the one or more devices to perform the operations described herein. The non-volatile, computer-readable storage medium can be an electromagnetic storage medium, a read-only memory (ROM), random-access memory (RAM), or erasable programmable memory (e.g.,a wipeable and programmable read-only memory (EPROM) and an electrically erasable and programmable read-only memory (EEPROM)), a flash memory or other non-volatile media currently known or developed in the future suitable for storing information, including but not limited to the following.

[0093] The operations of the one or more circuits and the one or more blocks herein are shown and described in a specific order; however, in some embodiments, the order of operations of each circuit / block may be changed so that certain operations may be performed in reverse order, or some operations may be performed at least partially simultaneously and / or in parallel with other operations. In other embodiments, instructions or sub-operations of different operations may be performed intermittently and / or alternately.

[0094] The patent description above describes the disclosure with reference to specific embodiments. However, it is obvious that various modifications and changes can be made to it without deviating from the concept and scope of protection of the disclosure, as set out in the accompanying claims. The patent description and the drawings are therefore to be regarded as exemplary and not as limiting.

Claims

[1] A procedure that includes the following: Backscattering, through an ambient power device (AMP device) that absorbs ambient energy, of radio frequency (RF) energy received in a wireless signal from at least one powered wireless device or wireless helper device; Causing the AMP device to transmit an initialization request frame within a backscattered signal to the powered wireless device using a first spreading code, wherein the first spreading code encodes a predetermined bit pattern detectable by the powered wireless device and an identifier (ID) of the AMP device; and Receiving, by the AMP device, from the powered wireless device, an ID request frame in response to the powered wireless device detecting the initialization request frame and recognizing the ID of the AMP device, the ID request frame initiating an attempt to initiate an encrypted wireless communication session with the powered wireless device. [2] Method according to claim 1, wherein the first spreading code is available at a known chip rate of the powered wireless device and comprises one of M sequences, Kasami sequences, Barker codes, Walsh codes, pseudonoise sequences, Zadoff-Chu sequences or Gold codes. [3] The method according to claim 1, further comprising: Wait for a random delay in response to the ID request framework not being received; and After waiting for the random delay time, cause the initialization request framework to be retransmitted to the powered wireless device. [4] Method according to claim 1, wherein the ID requirement framework includes a spread start value, wherein the method further includes: Determine, from the initial spreading value, a second spreading code that is specific to the AMP device; and Using the second spreading code to generate bitstreams that are contained in future frames, which are transmitted to the powered wireless device. [5] Method according to claim 4, wherein the second spreading code is shorter than the first spreading code or completely eliminates the spreading spectrum transmission. [6] Method according to claim 4, wherein the ID requirement framework includes a session ID, and wherein the method further includes: Retrieving, from a memory, a secret shared with the powered wireless device; Determine, using the secret, one or more initial authentication and key management parameters (AKM parameters); and Transmitted to the powered wireless device, using the second spreading code, an ID response frame containing the AMP device ID, the session ID, and one or more first AKM parameters to authenticate the powered wireless device and the AMP device to each other, and to generate an encryption key to initiate an encrypted wireless communication session. [7] Method according to claim 6, further comprising causing the ID of the AMP device to be listed first in the ID response frame in order to signal to the powered wireless device that the ID response frame originates from the AMP device. [8] A procedure that includes the following: at least periodic calculation, by a powered wireless device, of channel state information data (CSI data) within wireless signals received within a local environment; Spreading, through the powered wireless device, the CSI data at a predetermined chip rate to detect a bit pattern; Determine that the bit pattern contains an initialization request frame received by an ambient power (AMP) device; Detect, by means of the powered wireless device, an identifier (ID) of the AMP device that follows the initial pattern; and Transmitted to the AMP device in response to the detection of the AMP device's ID, an ID request framework, to initiate an attempt to establish an encrypted wireless communication session with the AMP device. [9] Method according to claim 8, wherein the initialization requirement framework is encoded using a known spreading code at the predetermined chip rate, the method further comprising the use of the known spreading code when unspreading the CSI data. [10] Method according to claim 8, wherein the CSI data also includes receive signal strength indicator data (RSSI data), wherein the method further includes using the RSSI data to spread the CSI data in order to detect the bit pattern. [11] The method of claim 8, further comprising at least one of the following: Transmitting a request to a wireless helper device that causes the wireless helper device to increase a transmit power directed to the AMP device; or Adjusting the direction of an antenna of the powered wireless device so that it is aligned with the AMP device. [12] Method according to claim 8, wherein the ID requirement framework includes a spreading start value from which the AMP device determines a device-specific spreading code. [13] Method according to claim 12, wherein the device-specific spreading code is shorter than an original spreading code that is transmitted at the predetermined chip rate, or that completely eliminates the spreading spectrum transmission. [14] Method according to claim 12, wherein the ID requirement framework further includes a session ID, wherein the method further includes: Unspreading the CSI data at an updated chip rate corresponding to the device-specific spreading code to detect a second bit pattern encoded with an ID response frame received from the AMP device, wherein the ID response frame includes an ID of the AMP device that is positioned first, the session ID, and one or more initial authentication and key management parameters (AKM parameters); and In response to the detection of the AMP device's ID, decode a remainder of the ID response frame received from the AMP device to obtain the initial AKM parameters with which to initiate the encrypted wireless communication session with the AMP device. [15] A wireless device comprising the following: an ambient power harvesting circuit (AMP harvesting circuit) configured to absorb ambient energy; at least one antenna; and a processing device coupled to the AMP collection circuit and the at least one antenna, wherein the processing device serves to cause the at least one antenna to perform the following: Backscattering of radio frequency (RF) energy received in a wireless signal from at least one powered wireless device or wireless helper device; Transmitting an initialization request framework to the powered wireless device within a backscattered signal using a first spreading code, wherein the first spreading code encodes a predetermined bit pattern detectable by the powered wireless device and an identifier (ID) of the wireless device; and Receiving, from the powered wireless device, an ID request frame in response to the powered wireless device detecting the initialization request frame and recognizing the ID of the wireless device, wherein the ID request frame triggers an attempt to initiate an encrypted wireless communication session with the powered wireless device. [16] Wireless device according to claim 15, wherein the processing device further serves to: Wait for a random delay in response to the ID request framework not being received; and After waiting for a random delay time, cause at least one antenna to retransmit the initialization request framework to the powered wireless device. [17] Wireless device according to claim 15, wherein the ID request framework includes a spread start value and wherein the processing device further serves to: Determine, from the spreading start value, a second spreading code that is specific to the wireless device; and Using the second spreading code to generate bitstreams that are contained in future frames, which are transmitted to the powered wireless device. [18] Wireless device according to claim 17, wherein the second spreading code is shorter than the first spreading code or which completely eliminates the spreading spectrum transmission. [19] Wireless device according to claim 17, wherein the ID requirement framework includes a session ID and wherein the processing device further serves to: Retrieving, from a memory, a secret shared with the powered wireless device; Determine, using the secret, one or more initial authentication and key management parameters (AKM parameters); and Causing the at least one antenna to transmit an ID response frame to the powered wireless device using the second spreading code, which includes the AMP device ID, the session ID, and one or more first AKM parameters used to authenticate the powered wireless device and the AMP device to each other, and generating an encryption key to initiate an encrypted wireless communication session. [20] Wireless device according to claim 19, wherein the processing device further serves to cause the ID of the AMP device to be listed first in the ID response frame in order to signal to the powered wireless device that the ID response frame originates from the AMP device.

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