METHOD FOR CALIBRATING RADIO CHANNEL PROBE ANTENNAS

Abstract

A computer-implemented method, when executed by data processing hardware, causes the data processing hardware to perform operations that include acquiring radio channel soundings between a first low-energy communication device and a second low-energy communication device, determining a number of antenna paths between two or more antennas, each coupled to the first low-energy communication device and the second low-energy communication device, and designing a link layer layout and interface protocol for the first low-energy communication device and the second low-energy communication device such that each antenna path is assigned at least one mode-0 step if the number of antenna paths is greater than three.and include performing an antenna calibration for a radio channel sounding procedure on the first low-energy communication device and the second low-energy communication device according to the link layer design and the interface protocol.

Description

INITIATIONThe present invention relates generally to a method of calibrating radio channel probing antennas.In this regard, for general background information, reference is first made in advance to CN 1 17 529 671 A. Further prior art is evident from the document entitled "High Accuracy, Low Cost Secure Ranging with Bluetooth Channel Sound" by NISARGA, B. (Application Note. Texas Instruments, February 2024; https: / / www.ti.com / lit / an / swra791 / swra791.pdf?ts=17223149066046&ref_url=https% 253A%252F%252Fwww.google.com%252F ) and from the article entitled "Bluetooth Channel Sounding - A Step Towards 10-cm Ranging Accuracy for Secure Access, Digital Key, and Proximity Services" by HILLYARD, J.; BACH-MANN, C.; HUANG, L. (Bluetooth Blog, November 30, 2023; https: / / www.bluetooth.com / blog / bluetooth-channel-sounding-a-step-towards-10-cm-ranging-accuracy-for-secure-access-digital-key-and-proximity-services / ).Generally, radio channel probing is a function of low energy communication devices (e.g., Bluetooth® Low Energy (BLE) devices) to measure and distribute information that can be used to estimate distances between two or more devices. In addition, radio channel probing may allow localization and / or positioning with three or more range measurements (i.e., a range measurement session for four or more devices). Therefore, radio channel probing may be desirable to identify a propagation path between the two or more devices. The current radio channel probing protocol does not allow more than three antenna paths to be properly calibrated, which may result in unreliable and inaccurate communication between devices. The deficiencies of the existing calibration protocol are addressed by one or more aspects of the present invention.SUMMARYAccording to the invention, a computer-implemented method is presented which is distinguished by the features of claim 1.When executed by data processing hardware, the method causes the data processing hardware to perform operations. The operations include detecting radio channel probe connections between a first low-energy communication device and a second low-energy communication device, detecting a number of antenna paths between two or more antennas respectively coupled to the first low-energy communication device and the second low-energy communication device, configuring a link layer configuration and an interface protocol of the first low-energy communication device and the second low-energy communication device in such a manner that each antenna path is assigned at least one mode 0 step when the number of antenna paths is greater than three, and performing antenna calibration for a radio channel probe method on the first low-energy communication device and the second low-energy communication device according to the link layer configuration and the interface protocol.The method may include one or more of the following optional features. For example, the at least one mode 0 step may further comprise adjusting the frequency and timing of each of the antenna paths to improve the reliability and accuracy of communication between the first and second low energy communication devices.According to at least one aspect, performing the antenna calibration may further include calibrating transmission and reception chains of the first low-energy communication device and the second low-energy communication device. Performing the antenna calibration for the radio channel probing method may further include calibrating the frequency of each antenna path. Performing the antenna calibration for the radio channel probing method may further include automatically calibrating a first amplifier of the first low-energy communication device and a second amplifier of the second low-energy communication device. Calibrating the first and second amplifiers of the first and second low energy communication devices may further comprise adjusting automatic gain control of the first and second amplifiers. Performing the antenna calibration for the radio channel probing method may further include calibrating the round trip timing of each antenna path.Further described is a system comprising a vehicle having a first low-energy communication device with data processing hardware and memory hardware associated with a transceiver coupled to two or more antennas, a mobile device having a second low-energy communication device with data processing hardware and memory hardware associated with a transceiver coupled to two or more antennas, wherein the memory hardware of the first and second low-energy communication devices stores instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations. The operations include detecting radio channel probe connections between the first low-energy communication device and the second low-energy communication device, detecting a number of antenna paths between two or more antennas respectively coupled to the first low-energy communication device and the second low-energy communication device, configuring a link layer configuration and an interface protocol of the first low-energy communication device and the second low-energy communication device in such a manner that each antenna path is assigned at least one mode 0 step when the number of antenna paths is greater than three, and performing antenna calibration for a radio channel probe method on the first low-energy communication device and the second low-energy communication device according to the link layer configuration and the interface protocol.The system may include one or more of the following optional features. For example, the at least one mode 0 step may further comprise adjusting the frequency and timing of each of the antenna paths to improve the reliability and accuracy of communication between the first and second low energy communication devices.According to at least one aspect, performing the antenna calibration may further include calibrating transmission and reception chains of the first low-energy communication device and the second low-energy communication device. Performing the antenna calibration for the radio channel probing method may further include calibrating the frequency of each antenna path. Performing the antenna calibration for the radio channel probing method may further include calibrating a first amplifier of the first low-energy communication device and a second amplifier of the second low-energy communication device. Calibrating the first and second amplifiers of the first and second low energy communication devices may further comprise adjusting automatic gain control of the first and second amplifiers. Performing the antenna calibration for the radio channel probing method may further include calibrating the round trip timing of each antenna path.Also provided is a communication system comprising a first low-energy communication device having a first amplifier, data processing hardware and memory hardware associated with a transmitter / receiver coupled to two or more antennas, and a second low-energy communication device having a second amplifier, data processing hardware and memory hardware associated with a transmitter / receiver coupled to two or more antennas. The memory hardware of the first and second low-energy communication devices stores instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations including detecting radio channel probe connections between the first low-energy communication device and the second low-energy communication device, detecting a number of radio frequency antenna paths between two or more antennas respectively coupled to the first low-energy communication device and the second low-energy communication device, configuring a link layer configuration and an interface protocol of the first low-energy communication device and the second low-energy communication device such that each antenna path is assigned at least one mode 0 step if the number of antenna paths is greater than three, and performing a radio frequency antenna calibration for a radio channel probing method on the first low-energy communication device and the second low-energy communication device according to the link layer configuration and the interface protocol.The system may include one or more of the following optional features. For example, the at least one mode 0 step further comprises adjusting the frequency and timing of each of the antenna paths to improve the reliability and accuracy of communication between the first and second low energy communication devices.In one aspect, performing the radio frequency antenna calibration may further include calibrating the transmit and receive chains of the first low energy communication device and the second low energy communication device. Performing the radio frequency antenna calibration for the radio channel probing method may further include calibrating the frequency of each antenna path.In another aspect, performing the radio frequency antenna calibration for the radio channel probing method may further include calibrating the first amplifier and the second amplifier of the second low energy communication device. Calibrating the first and second amplifiers of the first and second low energy communication devices may further comprise adjusting automatic gain control of the first and second amplifiers.BRIEF DESCRIPTION OF THE DRAWINGThe drawings described herein are for illustrative purposes only of selected configurations. FIG. 1 shows an operating environment with a vehicle, a mobile device and a communication system in a schematic illustration. FIG. 2 shows a radio channel probing method of the communication system of FIG. 1 in a schematic illustration. FIG. 3 is a flow chart showing the operations of the communication system of FIG. 1.Corresponding reference numerals designate corresponding parts throughout the drawings.DETAILED DESCRIPTIONExemplary configurations will now be described in more detail with reference to the accompanying drawings. Example configurations are provided so that this disclosure will be thorough. Specific details are set forth, such as examples of specific components, devices, and methods, in order to provide a thorough understanding of the configurations of the present disclosure.The terminology used herein is for describing particular exemplary configurations only. As used herein, the singular articles "a," "an," and "the" may also include the plural forms unless the context clearly indicates otherwise. The terms "comprise," "comprising," "include," and "have" are inclusive and therefore specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring execution in the particular order discussed or illustrated, unless expressly characterized as the order of execution. Additional or alternative steps may be employed.When an element or layer is referred to as being "on" or "engaged to" another element or layer or being "connected" or "coupled" or "attached" to the or same layer, it may be directly on or engaged to the other element or layer or connected or coupled or attached to the or same, or intervening elements or layers may be present. On the other hand, when an element is referred to as being "directly on" or "directly engaged to" another element or layer, or as being "directly connected" or "directly coupled" to or "attached to" the or same layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent," or "adjacent" versus "directly adjacent" or "directly adjacent," etc.). As used herein, the term "and / or" includes any combination of one or more of the associated listed items.The terms "first," "second," "third," etc., may be used herein to describe various elements, components, regions, layers, and / or portions. These terms may be used only to distinguish one element, component, region, layer, or portion from another region, layer, or portion. Terms such as "first," "second," and other numerical terms do not imply a sequence or order unless the context clearly indicates. Thus, a first element, component, region, layer, or portion discussed below could be referred to as a second element, component, region, layer, or portion without departing from the teachings of the example configurations.In this application, which includes the definitions below, the term "module" may be replaced by the term "circuit", the term "module" may refer to, be part of, or include an application specific integrated circuit (ASIC), a digital, analog, or mixed analog / digital discrete circuit, a digital, analog, or mixed analog / digital integrated circuit, a combinational logic circuit, a field programmable gate array (FPGA), a processor (common, dedicated, or group) that executes code, a memory (common, dedicated, or group) that stores code executed by a processor, other suitable hardware components that provide the described functionality, or a combination of some or all of the above components, e.g., in a system on a chip.The term "code" as used above may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, and / or objects. The term "common processor" includes a single processor that executes code from multiple modules in part or in whole. The term "group processor" includes a processor that, in combination with additional processors, executes code from one or more modules in part or in whole. The term "shared memory" includes a single memory that stores code from multiple modules in part or in whole. The term "group memory" includes a memory that, in combination with additional memories, stores code from one or more modules in part or in whole. The term "memory" may be a subset of the term "computer readable medium.". The term "computer-readable medium" does not include transitory electrical and electromagnetic signals propagating through a medium and may therefore be considered tangible and non-transitory memory. Examples of non-transitory memory include a tangible computer readable medium including a non-transitory memory, a magnetic memory, and an optical memory.The apparatuses and methods described in this application may be partially or fully implemented by one or more computer programs executed by one or more processors. The computer programs include processor-executable instructions stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include and / or be based on stored data.A software application (i.e., a software resource) may refer to computer software that causes a computing device to perform a task. In some examples, a software application may be referred to as an "application," "app," or "program.". Example applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social network applications, and gaming applications.The non-transitory memory may be physical devices that are for temporarily or permanently storing programs (e.g., command sequences) or data (e.g., program status information) for use by a computing device. The non-transitory memory may be a volatile and / or non-volatile addressable semiconductor memory. Examples of non-volatile memory include, but are not limited to, flash memory and read only memory (ROM) / programmable read only memory (PROM) / erasable programmable read only memory (EPROM) / electronically erasable programmable read only memory (EEPROM) (e.g., typically used for firmware such as boot programs). Examples of volatile memories include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase change memory (PCM), as well as floppy disks or tapes.These computer programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and may be implemented in a sequence-oriented and / or object-oriented programming language and / or in assembly / machine language. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, non-transitory computer-readable medium, apparatus, and / or device (e.g., magnetic disks, optical disks, memories, programmable logic devices (PLDs)) that is operable to provide machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal that serves to provide machine instructions and / or data to a programmable processor.Various implementations of the systems and techniques described herein may be implemented in digital electronic and / or optical circuits, integrated circuits, specially developed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations may include implementation in one or more computer programs executable and / or interpretable on a programmable system including at least one programmable processor that may be used for special or general purposes and is coupled to receive data and instructions from a storage system and to transmit data and instructions to a storage system, and at least one input device and at least one output device.The processes and logic flows described in this specification may be executed by one or more programmable processors, also referred to as data processing hardware, that execute one or more computer programs to perform functions by responding to input data and generating output. The processes and logic sequences can also be carried out by special logic circuits, for example an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). Processors suitable for executing a computer program include, for example, both general and special purpose microprocessors and one or more processors of all types of digital computers. Generally, a processor receives instructions and data from a read-only memory or a random-access memory, or both. The essential elements of a computer are a processor for executing instructions and one or more storage devices for storing instructions and data. Generally, a computer also includes or is operatively coupled to one or more mass storage devices for storing data, e.g., magnetic, magneto-optical, or optical disks, for receiving or transmitting data therefrom, or both. However, it is not necessary for a computer to have such devices. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and storage devices including, for example, semiconductor storage devices, e.g., EPROM, EEPROM, and flash memory devices, magnetic disks, e.g., internal hard or removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by special logic circuits or integrated into these.To enable interaction with a user, one or more aspects of the disclosure may be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) monitor, LCD (liquid crystal display) monitor, or touch screen for displaying information to the user, and optionally a keyboard and a pointing device, e.g., a mouse or trackball, by which the user may make input to the computer. Other types of devices may also be used to enable interaction with the user; for example, the user may receive any form of sensory feedback, e.g., visual feedback, audio feedback, or tactile feedback, and user inputs may be received in any form, including acoustic, speech, or tactile inputs. Moreover, a computer can interact with a user by sending and receiving documents to and from a device used by the user, e.g., by sending web pages to a web browser on a user's client device in response to requests received from the web browser.Referring to FIG. 1, an example operating environment 10 is provided to illustrate the principles of the present disclosure. The operating environment 10 includes a first device or vehicle 100 and a second or mobile device 102. The first and second devices 100, 102 may be any devices equipped with or otherwise capable of low energy communication (e.g., Bluetooth® Low Energy (BLE)). Thus, in another example, the first device 100 may be a wireless earphone and the second device 102 may be a mobile device.With continued reference to FIG. 1, the first device 100 includes a first or a first low-energy communication device (e.g., a Fahrzeug-Bluetooth® module) 104. The first low-energy communication device 104 includes data processing hardware 106 aand storage hardware 106 bin conjunction with a transmitting / receiving device 107 coupled to a first antenna 108 and a second antenna 109. A first amplifier 110 may also be coupled to or otherwise in communication with the transceiver 107. Likewise, the second device 102 comprises a second or a second low-energy communication device (e.g. a Bluetooth® module) 111. The second low-energy communication device 111 comprises data processing hardware 112 aand storage hardware 112 bin conjunction with a transmitting / receiving device 113 which is coupled to a third antenna 114 and a fourth antenna 115. A second amplifier 116 may also be coupled to or otherwise in communication with the transceiver 113. One or more parameters of the first and second amplifiers 110, 116, such as automatic gain control (AGC), may be controlled to prevent saturation of a transmit and receive chain between the first and second low energy communication devices 104, 111. The network or communication between the low energy communication devices 104, 111 may be referred to as a 2x2 multiple input multiple output (MIMO) system or communication system 117. In other examples, communication system 117 may include more or fewer antennas, such that communication is referred to as a 3x3 MIMO system, 4x4 MIMO system, or nxn MIMO system. In the present exemplary configuration, there are four (4) antenna paths (i.e., propagation paths, radio frequency paths, etc.) between the first and second devices 100, 102. With respect to the first antenna 108, a first antenna path 118 exists between the first antenna 108 and the third antenna 114 and a second antenna path 120 exists between the first antenna 108 and the fourth antenna 115. With respect to the second antenna 109, a third antenna path 122 exists between the second antenna 109 and the third antenna 114, and a fourth antenna path 124 exists between the second antenna 109 and the fourth antenna 115. It should be noted that adding additional antennas to the first low-energy communication device 104 and / or the second low-energy communication device 111 may increase the number of antenna paths.Referring to FIG. 2, the communication system 117 (i.e., the low energy communication devices 104, 111) may be configured with a link layer configuration 126 and an interface protocol 128. The link layer design 126 and the interface protocol 128 may further define a radio channel probing method 130 such that the antenna paths 118, 120, 122, 124 between the low energy communication devices 104, 111 may be characterized. The data obtained from the radio channel probing method 130 may allow one of the low-energy communication devices 104, 111 to determine the distance to the other of the low-energy communication devices 104, 111. Using the radio channel probing method 130, additional data may be collected, e.g., regarding round trip timing and phase-based ranging. In general, the radio channel probing method 130 consists of events 132, sub-events 134, and steps 136, which may be desirable to define a series of time and frequency slots in order for the low energy communication devices 104, 111 to communicate with each other and exchange radio frequency (RF) signals. In particular, the radio channel probing method 130 is divided into events 132. Events 132 consist of one or more sub-events 134. The sub-events 134 consist of the steps 136 and in particular of two or more steps 136 a, 136 bwhich each begin with a frequency change period 138. Within sub-events 134, first radio channel probing steps 136 aare used to provide calibration information for the remaining steps within that sub-event 134.There are four types of radio channel probing steps, including mode 0, mode 1, mode 2 and mode 3. In general, mode 0 can be used to calibrate the low energy communication devices 104, 111. In particular, according to one aspect, mode 0 may be used to calibrate antennas 108, 109, 114, 115 with respect to frequency and timing. Mode 1 may be used for round trip timing (RTT) packet exchange. Mode 2 may be used for exchanging radio channel probing tones with phase-based ranging to measure phase and amplitude of the communication channel. Mode 3 may be used to exchange both RTT and phase / amplitude measurements. Upon completion of the radio channel probing process 130, the low energy communication devices 104, 111 store the data collected by each radio channel probing step specifically for a given communication channel. Mode 0 steps may reflect local frequency adjustments. Mode 1 and mode 3 steps may measure the arrival and start times. Mode 2 and mode 3 steps may measure phase and magnitude information in the form of I&Q (in-phase and quadrature) measurements.Calibration of the antenna paths 118, 120, 122, 124 may be desirable to ensure that radio channel probing is reliable and accurate, but may present challenge with the previous protocol. The previous protocol provides up to three mode 0 steps, which serve only for repetition of interference and not for calibration of the individual antenna paths. In other words, the previous protocol is designed for redundancy and not for calibrating additional antenna paths of the communication system 117. Thus, in accordance with an aspect of the present disclosure, it may be desirable to configure the link layer configuration 126 to have at least one mode 0 step for each antenna path of the communication system 117 to improve the reliability and accuracy of the radio channel probing method 130. In particular, the addition of one or more additional mode 0 steps for each antenna path beyond three paths may allow proper frequency calibration, automatic gain control (AGC) calibration, and round trip timing calibration. Without proper calibration of the antennas, there is the possibility that after completion of the radio channel probing procedure 126, incorrect data may be provided to at least one of the four antennas. To improve accuracy, fewer radio channel probing measurements may be required between the first and second devices, thereby reducing latency and / or power consumption.Referring to FIG. 3, a method 200 for calibrating radio channel probing antennas is provided. At 202, method 200 is initiated. In practice, the method 200 is initiated whenever the communication system 117 (i.e., the first and / or second low energy communication devices 104, 111) uses the link layer configuration 126 and / or the interface protocol 128.At 204, the first and second devices 100, 102 may be configured to detect or otherwise determine when the other device (e.g., the first or second devices 100, 102) is attempting to perform a radio channel probing. Thus, for example, if the second low energy communication device 111 determines that the first low energy communication device 104 is attempting to perform a radio channel probing with the second low energy communication device 111, then the method 200 may proceed to 206.At 206, the first and second low-energy communication devices 104, 111 may determine the number of antennas coupled to or otherwise associated with the first and second low-energy communication devices 104, 111. The number of antenna paths may be determined or otherwise calculated based on the number of antennas coupled to the first and second low energy communication devices 104, 111. As indicated above with respect to FIG. 1, the communication system 117 includes four antenna paths between the first low-energy communication device 104 and the second low-energy communication device 111.At 208, the link layer layout 126 and / or the interface protocol 128 of the first low-energy communication device 104 and the second low-energy communication device 111 are designed in such a way that if the number of antenna paths is greater than three, at least one mode 0 step is assigned to each of the antenna paths 118, 120, 122, 124. According to at least one aspect of the present disclosure, the at least one mode 0 step may further include adjusting the frequency and timing of each of the antenna paths 118, 120, 122, 124 to improve the reliability and accuracy of communication between the antennas 108, 109, 114, 115. Additionally or alternatively, performing the calibration of the radio channel probing antennas may further include calibrating the transmit / receive chains of the first low energy communication device 104 and the second low energy communication device 111. Performing the calibration of the radio channel probing antennas may include calibrating the frequency, calibrating the automatic gain control, and / or calibrating the round trip timing for each of the antenna paths 118, 120, 122, 124. According to at least one aspect, performing antenna calibration for the radio channel probing method may further include automatically calibrating the first amplifier 110 of the first low-energy communication device 104 and the second amplifier 116 of the second low-energy communication device 111. Adjusting the automatic gain control of the amplifiers 110, 116 may be desirable to improve (i.e., reduce saturation) the performance of the transmit and receive chain between the first low energy communication device 104 and the second low energy communication device 111.The link layer configuration 126 and the interface protocol 128 may be stored in the memory hardware 106 bof the first and second low-energy communication devices 104, 111 as instructions that, when executed on the data processing hardware 106 a, cause the data processing hardware 106 ato perform operations according to the radio channel probing method 130.At 210, the radio frequency antenna paths 118, 120, 122, 124 of the antennas 108, 109, 114, 115 are calibrated according to the radio channel probing method 130. In other words, at 210, the antenna calibration for the radio channel probing method 130 is performed at the first low-energy communication device 104 and the second low-energy communication device 111 according to the link layer configuration 126 and the interface protocol 128.At 212, method 200 ends.A number of implementations have been described. It should be understood, however, that various changes may be made.

Claims

A computer-implemented method that, when executed by computing hardware, causes the computing hardware to perform operations comprising: detecting channel noise between a first low-energy communication device (104) and a second low-energy communication device (111); determining a number of antenna paths (118, 120, 122, 124) between two or more antennas (108, 109, 114, 115) respectively coupled to the first low-energy communication device (104) and the second low-energy communication device (111); configuring a link layer configuration (126) and an interface protocol (128) of the first low-energy communication device (104) and the second low-energy communication device (111) such that each antenna path (118, 120, 122, 124) is assigned at least one mode 0 step, when the number of antenna paths (118, 120, 122, 124) is larger than three, and performing antenna calibration for a radio channel probing method on the first low-energy communication device (104) and the second low-energy communication device (111) according to the link layer configuration (126) and the interface protocol.The method of claim 1, wherein the at least one mode 0 step further comprises adjusting the frequency and timing of each of the antenna paths (118, 120, 122, 124) to improve the reliability and accuracy of communication between the first and second low energy communication devices (104, 111).The method of claim 1, wherein performing the antenna calibration further comprises calibrating the transmit and receive chains of the first low energy communication device (104) and the second low energy communication device (111).The method of claim 3, wherein performing the antenna calibration for the radio channel probing method further comprises calibrating the frequency of each antenna path (118, 120, 122, 124).The method of claim 4, wherein calibrating the frequency of each antenna path (118, 120, 122, 124) further comprises calibrating the frequency at a first transceiver or a second transceiver.The method of claim 3, wherein performing the antenna calibration for the radio channel probing method further comprises automatically calibrating a first amplifier (110) of the first low energy communication device (104) and a second amplifier (116) of the second low energy communication device (111).The method of claim 6, wherein calibrating the first and second amplifiers (110, 116) of the first and second low energy communication devices (104, 111) further comprises adjusting automatic gain control of the first and second amplifiers (110, 116).The method of claim 3, wherein performing the antenna calibration for the radio channel probing method further comprises calibrating the round trip timing for each antenna path (118, 120, 122, 124).The method of claim 1, wherein the antenna paths are radio frequency antenna paths.The method of claim 1, wherein the first low energy communication device (104) comprises a first amplifier (110), data processing hardware (106a), and storage hardware (106b) in communication with a first transceiver coupled to the two or more antennas of the first low energy communication device (104), and wherein the second low energy communication device (111) comprises a second amplifier (116), data processing hardware (112a), and storage hardware (112b) in communication with a second transceiver coupled to the two or more antennas (114, 115) of the second low energy communication device (111).

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